Therapeutic patents for the treatment of pre-eclampsia

Review

10.1517/13543776.14.11.1579 © 2004 Ashley Publications Ltd ISSN 1354-3776 1579

Ashley Publicationswww.ashley-pub.com

1. Introduction

2. Antihypertensive agents

3. Nitric oxide

4. Magnesium therapeutics

5. Anti-inflammatory drugs

6. Modulators of trophoblast

invasion

7. Conclusions

8. Expert opinion

Monthly Focus: Cardiovascular, Renal, Endocrine & Metabolic

Therapeutic patents for the treatment of pre-eclampsiaNigel M PageSchool of Animal and Microbial Sciences, University of Reading, Reading, RG6 6AJ, UK

Pre-eclampsia (PE) is a pregnancy-specific syndrome that is a principal causeof maternal morbidity and mortality, accounting for almost 15% ofpregnancy-associated deaths. In its mild form, PE most commonly presentswith the features of maternal hypertension and proteinuria but can swiftlyand unpredictably become severe with many extensive and life-threateningcomplications. The diverse symptoms of PE have made it a difficult diseasenot only to define, but also to identify a causative agent for the symptoms. Ithas therefore proved difficult to develop specific drugs that can be used tomanage the condition. This review examines the patent literature to revealcurrent findings that exhibit the potential to target the effects of PE with theaim of either preventing or altering the course of this life-threateningdisease of pregnancy.

Keywords: angiotensin, anti-inflammatory, calcitonin gene-related peptide, digoxin, endothelin (ET), hypertension, magnesium, neurokinin B, nitric oxide, pre-eclampsia (PE), pregnancy, prostaglandins, trophoblast, vascular endothelial growth factor

Expert Opin. Ther. Patents (2004) 14(11):1579-1591

1. Introduction

The UK has a maternal mortality rate from conditions directly related to pregnancyof 6.1 per 100,000 maternal pregnancies [1]. Pre-eclampsia (PE) has been identifiedas the second leading cause of these deaths, following thromboembolism [1].However, these figures represent only the tip of the iceberg and data published bythe World Health Organisation (WHO) [2] show that for the > 500,000 maternaldeaths that occur every year, > 99% are in developing countries and < 1% in theindustrialised world. Worldwide, it is estimated that PE occurs in 3 – 10% of allpregnancies and contributes significantly to preterm birth, fetal growth retardationand stillbirth. Expectant mothers with the condition are also predisposed to thedevelopment of a range of potentially lethal complications, including acute renalfailure, hepatic failure and cerebral haemorrhage. It is estimated that 10 women and1000 babies will die each year in the UK as a direct result of the condition. Despitethis high incidence of PE, its aetiology remains unknown and this has led toconfusion and controversy in the criteria not only used for its classification anddiagnosis, but also in the development of therapeutic targets for its treatment.

The criteria for the classification of PE is currently defined by the NationalInstitutes of Health (NIH) [3] as: the development of hypertension normallyoccurring after the 20th week of gestation (represented by a rise of 30 mmHgsystolic or 15 mmHg diastolic blood pressure) that is accompanied by proteinuria(at least 0.3 g of protein in a 24 h specimen). In the absence of proteinuria, thecondition is suspected if hypertension is accompanied by headache, visualdisturbances, abdominal pain and rapid weight gain, or with abnormal laboratorytests. Also, seizures (eclampsia) may occur in a woman with PE, which cannot beattributed to any other cause. Hypertension and other symptoms of PE are foundto ultimately resolve by 12 weeks postpartum.

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Therapeutic patents for the treatment of pre-eclampsia

1580 Expert Opin. Ther. Patents (2004) 14(11)

Further, PE is differentiated from other forms of hyperten-sion observed during pregnancy. First, chronic hypertension isdefined as hypertension that is present before pregnancy ordiagnosed before the 20th week of gestation and that does notresolve by 12 weeks postpartum; and second, gestationalhypertension can be defined as hypertension that is detectedfor the first time after mid-pregnancy without proteinuria.The symptoms of PE may not develop and normally thediagnosis of gestational hypertension is only made 12 weekspostpartum when blood pressure has returned to normal.

Moreover, hypertension associated with PE is more omi-nous than the latter two forms as it can develop suddenly,with mild PE developing directly into severe PE over a matterof hours, days or weeks. This advancement can be bothunpredictable in its onset and its progression. It is importantto note that PE is more than just hypertension unique topregnancy as the disease is much more extensive and symp-toms can also occur in the absence of hypertension. These caninclude cerebral oedema [4], neurological manifestations(including headache, confusion, paralysis, coma, visual lossand seizures) [5], liver capsule distension [6], renal failure [7],pulmonary oedema [8], thrombocytopaenia [9], coagulopathy[10], HELLP (haemolysis, elevated liver enzymes, and lowplatelet count) syndrome [11] and nausea [12]. PE is thereforeregarded as a multi-system disorder/syndrome.

Current dogma proposes a two-stage model in the aetiologyof PE. The first stage appears to involve the defective tropho-blastic invasion of the placental bed, resulting in hypoper-fusion and an ischaemic placenta. The second stage appears toinvolve the release of an unknown factor(s) into the maternalcirculation from the placenta, which then causes the multi-system complications. Several steps in the development of thesecond stage have been proposed, including placental andendothelial dysfunction, that lead to oxidative stress and ageneral maternal inflammatory state. Maternal risk factorshave been identified that are believed not only to make themother’s uterus and the fetal placenta more prone to the ini-tial defective trophoblastic invasion, but also to sustain themother’s reaction to the release of the placental factors. Exam-ples of the risk factors involved are primigravidity, diet, raceand a previous history of PE. Many of the risk factors believedto be responsible for sustaining the maternal reaction in PEare also found to be related to those predicting the late onsetof adult atherosclerosis and cardiovascular disease [13-15].

There is little evidence to suggest that any of the currenttherapies alter the underlying pathophysiology of PE or atten-uate perinatal morbidity or mortality. This is particularly trueof the mainstay drugs, the antihypertensives, where hyperten-sion would appear secondary to the cause of the disease. Trialson pharmacological prevention have been disappointing, andgood pregnancy management, providing continual maternaland fetal monitoring as well as non-pharmacological regimes,such as early delivery, remains at the basis of PE treatments.

Many different targets have been identified to treat thedifferent symptoms of PE (reviewed in [16]). This present review

aims to provide a general prognosis of the most recent patent lit-erature pertaining to the emerging targets being developed for theprevention and treatment of PE. It is not intended to provide anoverview and update of the primary literature sources, or providea comprehensive review of all compounds patented with PElisted as only a potential indication with little or no justification.

2. Antihypertensive agents

A casual link between the increased use of antihypertensivedrugs during pregnancy and the coincidental fall in the fre-quency of cerebral and hepatic lesions occurring during PE hasbeen made [1]. While there are positive benefits to receivingtherapy for severe hypertension, the role of antihypertensivetherapy in mild-to-moderate PE is less clear [17] and needs fur-ther investigation. There are few trials to guide the choice ofantihypertensive drugs during pregnancy and most data hasbeen collected from limited trials. To date, most data fromclinical trials using drugs normally used to treat essentialhypertension show the centrally-acting α-adrenergic agent,methyldopa (Aldomet, Merck) to be the best choice of drugfor the first-line treatment of PE. A range of other patenteddrugs has also been used in the clinic, including αβ-blockers,β-blockers, calcium channel blockers, direct vasodilators, diu-retics and angiotensin-converting enzyme (ACE) inhibitors.However, these agents have side effects in pregnancy; β-block-ers have been associated with fetal growth retardation [18]; diu-retics may reduce the already low plasma volume of a PEpatient [19], and ACE inhibitors are absolutely contraindicatedin pregnancy and are associated with fetal growth retardation,oligohydramnios, neonatal renal failure and neonatal death[20]. Consequently, the development of antihypertensive thera-pies during pregnancies presents considerable challenges. All ofthe drugs developed to treat essential hypertension have beenderived from the non-pregnant population and for ethical rea-sons this is likely to remain the case. This review will give con-sideration only to the recently emerging drug targetsreferenced in the patent literature.

2.1 Endothelin-1It has been postulated that the vasoconstricting potential ofpressor substances (e.g., angiotensin II and endothelin [ET])are magnified in PE as a consequence of a decreased activityof nitric oxide (NO) synthetase and subsequent NO reduc-tion [21]. The vascular endothelium releases a variety of thesevasoactive substances, including ET-1, ET-2 and ET-3, themost potent vasoconstrictors identified [22]. They bind toET-A and ET-B receptors causing marked and sustainedrises in blood pressure. The predominant ET, ET-1, is syn-thesised from a 203 amino acid precursor, which first yieldsbig ET by proteolytic cleavage, a 38 amino acid peptide.Further cleavage to ET-1, performed by ET convertingenzyme (ECE), is essential for the induction of full vasocon-strictor activity [23]. A process that is blocked by non-specificmetalloproteinase inhibitors such as phosphoramidon [24].

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Expert Opin. Ther. Patents (2004) 14(11) 1581

In PE, elevated levels of ET-1 are found in the maternalblood when compared with normal pregnant women.Whereas a negative correlation between ET-1 concentrationsin the umbilical vein and birth weight suggests that ET-1plays a pathophysiological role in PE [25]. Also, circulating ETlevels in women with PE correlate closely with serum uric acidlevels and measures of renal dysfunction [26]. Likewise, ECEactivity is found to be higher in women with PE [27]. An ani-mal model of PE has been used to determine the therapeuticrole of ET by studying the effect of a specific ET antagonist,BQ-123 (Banyu Pharmaceutical Co.), on blood pressure [28].Infusing pregnant rats with the NO synthase inhibitor,N(G)-nitro-L-arginine methyl ester, induced a PE-like condi-tion. BQ-123 was successful at attenuating the effects of ele-vated blood pressure, proteinuria and fetal growth retardationsupporting a role for ET in this conditioned PE-like response.This has provided the basis by which Schering AG haveclaimed a method for the prevention and treatment of PEwith an ET antagonist and/or an ET synthase inhibitor incombination [201]. The use of a progestin in combination hasalso been recommended, as progesterone withdrawal in thethird trimester of rat pregnancy has been associated with a risein blood pressure [29,201].

Several ET receptor antagonists are under consideration aswell as compounds that can influence the activity of the ECE.Only one compound, bosentan (Tracleer, Actelion Pharma-ceuticals, Inc.), has entered Phase III clinical trials but atpresent has been shown to be less potent then the ACE inhib-itor, enalapril (Vasotec, Biovail). ECE inhibitors may thus beuseful. In general terms, several new ET antagonists have beendescribed for potential use in the treatment of PE, these repre-sent the largest group of patented antihypertensives aimed atcombating PE. Several compounds have been devised byWarner-Lambert Co., including novel nonpeptide ketoacidbased derivatives [202] and those with modified ether-linkedgroups [203], acylated peptides [204] and novel linear andmonocyclic antagonists [205]. However, there is no evidence tosuggest that any of these particular modifications have beentailored specifically to combat PE. Multi-binding compoundshave also been described by Theravance, Inc., comprising aplurality of ligands, each of which can bind to ET receptors,thereby modulating their biological processes/functions. Eachof the ligands, which may be the same or different, are cova-lently attached to a linker or linkers in a construction toincrease the modulation of the biological response [206].Theravance, Inc. has also applied a similar approach to thedevelopment of α2-adrenergic receptor agonists for thepotential treatment of PE [206].

The importance of ECE inhibitors is supported in the sup-pression of the pressor activity of ET. Certain known andnovel quinazoline derivatives have now been shown to beinhibitors of ECE. The quinazoline compounds of a patentfrom Warner-Lambert Co. [207], present novel non-peptidicECE inhibitors are thus useful in treating diseases associatedwith elevated levels of ET, including PE. The tri-substituted

quinazoline PD-069185 (Warner-Lambert Co.) is shown tobe effective at attenuating the increase in perfusion pressureinduced by big ET-1 in isolated rat mesentery [30]. Quinazo-line compounds may also help counter other symptoms ofPE, including inflammation, hypertension and thrombosis byinhibiting thromboxane A2 (TXA2) synthetase. A patentfrom Ono pharmaceutical Co, EP-579496 [208], describes4-aminoquinazolines with inhibitory effects on TXA2 syn-thetase; PE is associated with excessive production of theplatelet-derived vasoconstrictor thromboxane. Furthermore, aseries of bi-aryl pyridine carboxylic acids (Warner-LambertCo.) [31,209] and peptides that relate to novel hydroxamateinhibitors (Warner-Lambert Co.) are also shown to beinhibitors of ECE [210,211].

Although a significant number of innovations relating to theuse of ET antagonists and ECE inhibitors for PE exist in thepatent literature, there is no definite reason why ET antagonistswould be more beneficial than other antihypertensives cur-rently available. However, it is clear that serum ET-1 levels aresignificantly elevated in women with PE, with a prompt declinein levels 48 h after birth [32]. Also, injections of ET-1 into preg-nant rabbits produce eclamptic-like seizures [33], and ET-1induces neutrophil activation in PE patients [34]. ET therapycould therefore directly abrogate ET-induced hypertension andany associated PE symptoms. Indeed, administration ofTracleer into rats at gestation day 19 significantly increased pla-cental and myometrial blood flow [35]. However, contradictionsin ET antagonist use during pregnancy have recently come tolight. In the rat, the pharmacological knockout of ET-A recep-tors leads to undesirable phenotypes, including craniofacialabnormalities and major vessel anomalies [36]. Correspondingly,ET-B receptor antagonism is also shown to inhibit fetal growth,and increases maternal mean arterial pressure in a dose-depend-ent manner [37]. It is important to note that ET-1 is alsobelieved to act as a mitogenic stimulus for first trimestertrophoblastic cells in vitro [38].

2.2 Angiotensin IIAngiotensin II (AII) is another potent vasoconstrictor associ-ated with PE. It is generated from AI, an inactive peptide thatis released after cleavage of angiotensinogen by renin. At leasttwo distinct subtypes of AII receptors have been identified,designated AT1 and AT2. In women with PE, it was firstshown that AII concentrations in maternal, as well as umbili-cal plasma, were significantly higher than concentrations inuncomplicated pregnancies [39]. However, some researchershave since found reduced maternal plasma AII levels in PEcompared with those in normal pregnancy [40]. Neither isthere any significant difference in maternal ACE activity inwomen with or without PE [41]. Whether the feto-placentalrenin-angiotensin system in PE is accelerated is still controver-sial, although in the feto-placental unit the placenta is themost likely site for conversion of AI to AII by ACE. Distinctfrom ET-1, most studies now find plasma AII concentrationsare reduced in PE, whereas there is heightened pressor

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sensitivity to infused AII – the mechanism(s) for this beingunknown [42]. Interestingly, Wallukat et al. (1999) [43] investi-gated 25 PE patients and compared them with 12 normoten-sive pregnant women and 10 pregnant patients with essentialhypertension. Antibodies were detected from all PE patientsthat stimulated the AT1 receptor, whereas immunoglobulinfrom controls had no effect. The increased autoimmune activ-ity decreased after delivery. Peptides corresponding to sites onthe second extracellular loop of the AT1 receptor abolished thestimulatory effect suggesting that PE patients develop stimu-latory auto-antibodies against the second extracellular AT1

receptor loop. It may be that these novel auto-antibodies mayparticipate in the AII-induced vascular lesions during PE.Peptides to the AT1 receptor with the sequence AFHYESQ,AVHYQSN, SHFYQTR, GYYFDTN or ENTNIT are pro-posed by Max Delbrueck Centrum for their use in eliminat-ing the specific binding of the pathological antibodies foundin PE [212].

Therefore, AII antagonists may have potential for the treat-ment of PE, but their safety is questioned regarding their asso-ciation with the effects of the ACE inhibitors duringpregnancy. It is suggested that the use of AII receptor antago-nists, such as losartan (Cozaar, Merck) and valsartan (Diovan,Novartis), could have similar adverse effects to the ACEinhibitors. However, there is no real human data on the use ofAII receptor antagonists in pregnancy, and it has beenreported that in mice the inactivation of angiotensin receptorsdoes not result in the same developmental abnormalities asthe inactivation of ACE [44]. This suggests a possible redun-dancy in the renin–angiotensin system that prevents thedevelopment of renal pathology. As a result the categorisationof the AII receptor antagonists with ACE inhibitors may per-haps be unfounded. Further AT1 receptor antagonists appearto be as effective as the ACE inhibitors in treating hyperten-sion, without the dry-cough side effect [213]. Because the AT1

receptor possesses a multiple proximal binding domain thatincludes N-terminal and extracellular loops involved in pep-tide binding, multimeric ligand compounds possessing multi-binding properties for the AT receptors are proposed byAdvanced Medicine, Inc. in the treatment of PE [213]. Thecombination of 2 – 10 functionalised ligands (e.g., losartanand valsartan) with complementary functionalised linkerswould allow either the presentation of a single type of ligandor a mixture of ligands [213]. This enables a range of ligandorientations that possess enhanced biological and/ortherapeutic effect arising from their ability to bind in amultivalent manner.

2.3 Calcitonin gene-related peptide.Calcitonin gene-related peptide (CGRP) is a 37 amino acidneuropeptide, which is the most potent naturally-occurringvasodilator peptide in the human body. During pregnancy theCGRP effects on blood pressure and uterine relaxation appearto be progesterone-dependent as CGRP appears especiallyeffective during pregnancy when progesterone levels are

elevated. These effects are abolished after delivery of the fetus[45]. Thus, combinations of CGRP with progesterone are indi-cated to be particularly efficacious for the treatment and pre-vention of PE. The actions of CGRP treatment withprogesterone and nitric oxide are augmented in the presenceof a cyclooxygenase inhibitor and angiotensin receptor antag-onists (such as Cozaar). Wimalawansa et al. [45] examined theeffect of CGRP to ameliorate N(G)-nitro-L-arginine methylester (L-NAME)-induced hypertension during rat pregnancyand the efficacy of CGRP and progesterone in combinationto inhibit L-NAME-induced hypertension during the post-partum period. CGRP infusion inhibited L-NAME-inducedhypertension to normotensive levels during pregnancy (up today 22 of gestation), but not during the postpartum period.During the postpartum period, neither progesterone orCGRP by itself was effective in lowering L-NAME-inducedhypertension, but the combination of CGRP with progester-one decreased BP to control levels in the postpartum period,and also significantly improved fetal mortality and growth.Therefore, University of Texas claims that the combination ofCGRP plus progesterone for treatment may be a promisingtherapy in the management of PE [45,214].

2.4 Neurokinin BNeurokinin B (NKB) belongs to a family of peptides calledtachykinins. NKB has been found to be the most potentneurokinin to cause vasoconstriction of both the mesentericvascular bed [46] and the contraction of the hepatic portal vein[47]. NKB is also the most potent member of the family to actat the NK3 receptor and, whereas substance P andneurokinin A slow down the heart rate, NK3 receptoragonists have the opposite effect in that they increase heartrate when perfused in the canine coronary arterial bloodsupply [48]. In an animal model, intravenous injections ofNKB into guinea-pigs have been shown to produce a dose-related hypertension, and very high levels of NKB agonistwere shown to lead to animal discomfort [49]. Similar experi-ments show an increase in blood pressure upon intravenousinfusion of NKB in rats [50]. Page et al. [50] found NKB con-centrations to be remarkably high (1 – 7 nmol/l) in theplasma of eight women with PE in the third trimester. A com-parison with 30 normotensive pregnant women revealed lowor undetectable levels throughout pregnancy, although a pro-portion exhibited a slight rise at term (< 1 nmol/l). Elevatedlevels in PE are proposed to lead to a reduction in blood flowto the liver causing an accumulation of toxic metabolic prod-ucts, such as lipid peroxides, that may contribute to endothe-lial cell damage and dysfunction. In the more severe cases, theconcentrations of NKB may be sufficient to stimulate periph-eral NK1 and NK2 receptors on platelets, neutrophils and thecerebral vasculature. The University of Reading therefore sug-gests that NK3 receptor antagonists could lower hypertensionin women with high circulating levels of NKB, whilst NK1and NK2 receptor antagonists could be used to tacklepotential coagulation and inflammation problems [215]. In

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such circumstances a combination of NK3 and NK1 receptorantagonists, or a broad spectrum NK receptor antagonist,may be the drug of choice. However, care may need to betaken in the administration of NK1 antagonists, as NKBappears to be responsible for inducing placental vasculaturevasodilatation via the NK1 receptor [51,52]. Furthermore, theinfusion of the NK3 antagonist SR-142801 (Osanetant,Sanofi Recherche) during rat pregnancy has been shown tocause a reduction in litter size [53].

2.5 Digoxin-like immune factorsOne theory proposes that elevated serum digoxin-likeimmune factors, which have sodium/potassium ATPaseenzyme inhibitor activities, may play a central role in theincreased peripheral vasoconstriction of PE [54]. This isbelieved to occur by mediation of an ion exchange pumpthat results in increased intracellular calcium that promotesvasoconstriction and the resultant hypertension. Based onthis theory, it has been suggested that the use of digoxinimmune Fab (ovine) antibodies may be productive in con-trolling PE and eclampsia and extending pregnancy. Suchdigoxin-like immunoreactive substances are found to be sig-nificantly higher in PE than that in healthy control subjects[54]. One case report by Adair CD has outlined a second tri-mester multifetal pregnancy associated with PE that was suc-cessfully treated by infusion of a digoxin-bindingimmunoglobulin with no untoward maternal side effects[55,216]. In accordance with this observation, a method forregulating the sodium/potassium ATPase activity of a PEpatient by the administration of digoxin immune Fab(ovine) was proposed. The ultimate aim was to allow thepatient’s intracellular sodium and calcium to return to amore normal level [217]. Although the use of digoxinimmune Fab (ovine) in the treatment of PE and eclampsiahas shown promise, a truly efficacious method of calculatingsuitable dosages of and administering the drug have so fareluded researchers in this field.

Numerous investigators have reported the existence of otherendogenous digoxin-like factors isolated from various biologi-cal fluids. These agents include ouabain-like agents isolatedfrom bovine hypothalamus [56], human urine and bovineplasma [56]. Moreover, US5028438 [218] and US5122371 [219],respectively, describe some of these biologically-active agents ashaving hypotensive activities in mammals, although somereports suggest that too high concentrations may play a crucialrole in the development of essential hypertension [57]. Thesecompounds could offer therapeutic potential to compensatefor the drawbacks (impotence, weakness and depression) asso-ciated with the use of digoxin to treat hypertension and heartfailure [220]. Kerix LLC have found some of these digoxin-likefactors to be phosphocholinate cardenolides that also haveantihypertensive activity in mammals [220]. Kerix LLC believedthat such compounds could have a better therapeutic indexthan digoxin or digitalis because they are endogenous, and asdegradation is expected to occur by a natural metabolic

pathway. In this case, the selection and use of naturally-occur-ring antihypertensive agents during pregnancy has been specif-ically claimed as advantageous in the treatment of PE [220].However, it should be noted that contrary reports indicate thatin PE, high levels of circulating bufodienolides and cardeno-lides are present [58]. Such plasma concentrations are believedto be enough to substantially inhibit the sodium pump in car-diovascular tissues, and may attribute to a pathogenic role inthe PE hypertension [58]. In this context perhaps it is antago-nists of these endogenous digoxin-like factors that should besought in future patent claims.

2.6 ProstaglandinsIt has been suggested that the increase in vascular tone in PE iscaused by a relative or absolute deficiency in the production ofthe vasodilating prostaglandin, PG12 (prostacyclin). It has alsobeen suggested that abnormalities in eicosanoid metabolismmay play a role in the pathogenesis of PE, reflecting an imbal-ance between production of vasodilating prostacyclin and thevasoconstrictor effects of thromboxane. The first treatmentwith the TXA2 inhibitor, Xanbon (Ozagrel, Daiichi) resultedin a significant decrease in maternal blood pressure andnormalised umbilical artery waveforms [59]. A recent trial ofozagrel hydrochloride, a TXA2 synthetase inhibitor, producedsimilar promising results and has been suggested for preven-tion in high-risk PE groups [60]. However, Sullivan et al. [61]

suggested that the use of thromboxane synthetase inhibitorsmay result in preterm labour or abortion, by increasing theproduction of prostaglandins E2 and F2α, and should not beused in pregnancy. A study into the effects of prostacyclin ago-nists on blood pressure in a rat model of PE has demonstratedthat hypertension can be partially reversed with prostacyclinanalogues [62]. Several new prostaglandin modulators havebeen described by Applied Research Systems, includingpyrrolidine derivatives [221], pyrazolidinone compounds asligands of the prostaglandin EP2 and/or EP4 receptors [222],and thiophene and furan derivatives [223]. Prostaglandin modu-lators may also be used to determine the outcome of cervicalripening. One study has shown that PE patients showed alower rate of successful ripening and vaginal delivery whencompared with non-PE or non-hypertensive patients. Theysuggest the use of intracervical prostaglandin E2 [63].

3. Nitric oxide

NO is synthesised from the non-essential amino acidL-arginine by nitric oxide synthase (NOS). In normal preg-nancy, haemodynamic adaptation is accompanied by anincrease in NO production [64] and responsiveness [65]. NOproduced in endothelial cells activates a cyclic guanidinemonophosphate pathway to produce vascular smooth musclerelaxation [66], whilst in the vascular system it has the capabil-ity to inhibit vasoconstrictors such as TXA2 [67] and stimulatevasodilators such as prostacyclin [68]. In the perfused placentathe effect of inhibitors on the release of NO was found to

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cause increases in perfusion pressure during vascular constric-tion with submaximal concentrations of TXA2. This impliedthat NO could attenuate the vasoconstrictor response andthat the impairment of NO release or function could lead tothe observed decrease in blood flow to the placenta during PE[69]. This led to the conclusion that in PE, dysfunction of theNO system leads to a deficiency of NO. Furthermore, theinfusion of an inhibitor of NO synthesis into rats duringpregnancy caused hypertension, fetal growth retardation andsymptoms similar to PE [70] and this raised the possibility oftreating an experimental animal model for PE using eitherNO, NO precursors or NO donors.

The unstable nature of NO has complicated the viability ofits use directly as a therapeutic agent. However, NO has beenfound to be soluble and stable in deoxygenated perfluorocompound emulsions [224]. When dissolved in such perfluorocompound emulsions, NO is stable for periods of at least 14days and is suitable for injection into the human blood systemwith the solvent allowing slow release to the affected tissues[224]. Nevertheless, the preferred treatment options for PE arethe NO precursors and donors. L-Arginine treatment of ratswas found to reverse a PE-like syndrome with lowering ofsystolic blood pressure, increased pup weight, decrease in pro-teinuria and a decrease in injured glomeruli [71,225]. Also,L-arginine infusion into women with normal pregnancies andthose complicated by PE, both benefited from a significantreduction in blood pressure [225]. Another study examined theeffects of the NO donor, molsidomine, in similarly inhibitedrats and also observed a lowering of blood pressure, howevermolsidomine actually worsened the fetal outcome [72]. NOdonors such as glyceryl trinitrate and sodium nitroprusside areshown to be potent venous vasodilators on the vessels of thehuman placenta and are suggested as options for possible earlytreatment [73]. Sublingual administration of glyceryl trinitratehas been used to treat mild PE [74] and treatment resulted in agreater reduction of the resistance to blood flow in the feto-placental circulation in women with PE. Infusion of the plate-let-specific NO donor S-nitrosoglutathione reduced maternalmean arterial pressure, platelet activation and uterine arteryresistance without further compromising fetal Doppler indi-ces [75,226]. Furthermore, the therapeutic value of NO donorscan been enhanced by the synergistic effect of a progestationalagent administered concurrently [227,228]. The progesteroneagonist, promegestone (R-5020) was shown to reduce bloodpressure and increase fetal weights in L-NAME-treated preg-nant rats [29,227,228]. High levels of steroid hormones, particu-larly progesterone, during pregnancy are understood tomodulate either the production or action of NO [76]. Besidesthese examples, any agent that can mimic the effects of NO atits endogenous receptor is beneficial. Indeed, in the vascula-ture, the binding of NO to soluble guanylate cyclase (sGC) isresponsible for vascular and non-vascular smooth musclerelaxation and platelet reactivity [77]. Therefore, activators ofsGC can be expected to have valuable therapeutic properties.1-benzyl-3-(3-dimethylaminopropyloxy)indazole has been

identified as one such potent activator of sGC demonstratingnot only potent activation of sGC, but potent inhibition ofplatelet aggregation [78,229].

There is also interest in enhancing endogenous NO synthe-sis by providing citrulline or a citrulline analogue in the treat-ment of PE. Citrulline is produced together with NO fromL-arginine by the action of NO synthase. Nevertheless, rela-tively little is known about the pathway(s) by which cells syn-thesise or metabolise L-arginine. However, cells are known toconvert/recycle L-citrulline to L-arginine in an arginine–citrulline cycle by the intermediate formation of arginosucci-nate. [79]. US2001056068 [230] recognises the therapeuticpotential of citrulline, demonstrating that NO deficiencysymptoms can be attenuated by raising the endogenous NOlevels with citrulline treatment. Additionally, US5874471 [231]

claims administration of sizeable amounts of L-citrulline as aprecursor substance for bioconversion to L-arginine in orderto maintain greater blood plasma concentrations ofL-arginine. The inventor claims its use in orthomolecularmedicine in that it uses a substance normally present in thehuman body to increase the availability of another substancethat is normally also present in the human body.

4. Magnesium therapeutics

Magnesium is nutritionally important for maintenance of vas-cular integrity. Deleterious vascular effects of magnesium defi-ciency include cardiac arrhythmias and hypertension [80],whereas magnesium supplements have been shown to reducesuch hypertension [81]. Many women, especially those fromdisadvantaged backgrounds, have intakes of magnesiumbelow recommended levels. It has been proposed that magne-sium supplementation during pregnancy may be able to helpreduce fetal growth retardation, the incidence of PE andincrease birth weight. A recent analysis, of seven trials involv-ing 2689 women, compared oral magnesium treatment andplacebo given from before the 25th week of gestation. A lowerfrequency of preterm birth, (relative risk [RR] = 0.73, 95%,confidence interval [CI] = 0.57 – 0.94), low birth weight(RR = 0.67, 95%, CI = 0.46 – 0.96) and fewer infants, smallfor their gestational age (RR = 0.70, 95%, CI = 0.53 – 0.93)was associated with the magnesium supplement [82]. Moreover,early reports suggested that a daily magnesium supplementcould completely prevent PE [83], but this has not been con-firmed using recent randomised trials [84]. However, magne-sium sulfate has been used extensively in the management andprevention of eclamptic seizures. The Magpie Trial: a ran-domised placebo-controlled trial partaken by 10,141 womenin 33 countries has demonstrated that magnesium sulfatereduces the risk of eclampsia by 58%, and also reduces the riskof maternal death. No substantive harmful effects to mother orbaby in the short-term were reported [85]. Nutrition 21, hasproposed magnesium taurate as a more effective parenteraltherapeutic/prophylactic for PE than magnesium sulfate[86,232]. Taurine has antihypertensive, antivasopressor,

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platelet-stabilising, hypoxia-protective and anticonvulsantproperties that would complement the vascular-protective andanti-eclamptic actions of magnesium, whereas the sulfate ionitself has no antihypertensive effects [232]. Additionally, tauratein the form of a salt or a complex could also be complexedwith calcium or zinc. Serum calcium levels are found to besignificantly lower in PE patients [87], where extracellular cal-cium ions have been shown to be crucial for synthesis ofvasoactive substances in the endothelium such as prostacyclinand NO [88]. A meta-analysis study comprising 1218 pregnantwomen taking a daily calcium supplement of 1.5 – 2.0 gobserved a significant drop in systolic and diastolic bloodpressure in the women with PE [89]. Nevertheless, the mostrecent study from the ‘Calcium for PE Prevention study’ hasshown that body mass index, race and smoking are far moreimportant factors than nutritional factors [90].

Some essential hypertensive patients and genetic hyperten-sive rat strains have a magnesium binding defect. This bind-ing defect appears to cause increased passive permeability ofthe membrane to sodium ions and thereby increases its intra-cellular concentration, increasing smooth muscle cell tonethat in turn leads to hypertension [91]. A lack or decreasedconcentration of the decapeptide tachykinin substance P inthe blood plasma is proposed as the cause of this magnesiumbinding defect. The addition of substance P, or its C-terminalregion pentapeptide or tetrapeptide corrects this magnesiumbinding by an unknown mechanism. In vivo, the intravenousadministration of the tetrapeptide corrects hypertension [91].The use of substance P peptides or non-peptide derivatives istherefore proposed by Magnesium Diagnostics, Inc. in thetreatment of PE [233].

5. Anti-inflammatory drugs

To maintain the patency of blood vessels and the fluidity ofblood, endothelial cells synthesise many active substances,including molecules such as fibronectin, heparin sulfate, tissueplasminogen activator and prostacyclin. In doing so, endothe-lial cells modulate the reactivity of underlying vascular smoothmuscle in response to these vasoactive stimuli.

One such factor, heparin, serves several functions inendothelial membranes, including antiproliferative functions.A biological extract, sulodexide, comprising of ∼ 80% heparinor heparinsulfate and 20% dermatan sulfate has been shownby Lakaro Biopharmaceutical, Inc. to have anticoagulant andantithrombotic actions in experimental animals [234]. Sulodex-ide essentially catalyses the inhibition of thrombin generationin situ similar to that of low molecular weight heparin. How-ever, it has the advantage over heparin of causing much lessbleeding, which is undesirable in a pregnant subject. Further,it has been shown that endogenous heparin levels and anti-thrombin III activity decrease by nearly 50% within 15 daysof the development of PE and are particularly low 1 – 7 daysbefore the onset of clinical signs of PE [92]. Hence,compounds aimed at reversing the effects of low heparin levels

may be beneficial in treating PE. The use of heparin, heparinsulfate and dermatan sulfate, such as sulodexide, forms thebasis of patent EP-1016410 [234].

Endothelial cell injury and dysfunction is a common fea-ture of PE [93], and the prevention or repair of injury toblood vessels may help to protect from further damage. Ang-iogenic factors are capable of promoting the growth of newblood capillary vessels from existing endothelium andincreasing vascular permeability. They include substanceslike the vascular endothelial growth factors (VEGFs), plate-let-derived growth factors (PDGFs) and the fibroblastgrowth factors (FGFs). Subsequently, the embodiments ofpatent US2003220262 are designed to protect a whole hostof angiogenic factors including polypeptides, peptides andsmall molecules without reference to each of their therapeu-tic values [235]. Tap Pharmaceuticals, Inc. have foundstraight-chain alkanoic acids to be effective therapy in thelipid peroxide injury of the vascular endothelium occurringin PE. These alkanoic acids have been specifically substi-tuted at the OMEGA-carbon atom by a substituted phenyl,naphthyl, furyl, or thienyl group and by a substituted1,4-benzoquinon-2-yl group [236]. They are believed to actby inhibiting the formation of lipid peroxides, as TXA2antagonists, and as inhibitors of 5-lipoxygenase [236].

Recently, placental VEGF was proposed to be involved inPE. Originally Baker et al. [94] found elevated serum levels inpatients with PE and suggested a role for VEGF in endothe-lial cell activation. It was later confirmed that the elevatedlevels of VEGF correlated with the severity of hypertension[95] and possibly the extravasation of plasma proteins and thesubsequent development of proteinuria [96]. Conversely, ithas also been reported that PE is associated with lower levelsof VEGF than normal [97]. VEGF expression is normallyupregulated during hypoxia but found to be reduced in theplacenta of women with PE shown by using either immu-nolocalisation [98] or mRNA expression levels [99]. These lowlevels have lead to the suggestion that impaired vasculardevelopment may occur in the placenta [97]. VEGF interactsthrough three different receptors: VEGFR-1 (flt-1),VEGFR-2 (KDR/flk-1) and VEGFR-3 (flt-4) and thesereceptors may mediate different functions within endothe-lial cells. The sVEGFR-1 (sflt-1), a soluble receptor, hasbeen located to the placental trophoblast by in situ hybridi-sation. Serum from pregnant women was found to containsflt-1, which was not present in serum from non-pregnantfemales or males. The secretion of sflt-1 from the placentaappears to be a novel mechanism for regulating the levels ofVEGF in the circulation [99]. The endothelium-dependentrelaxation of blood vessels incubated in the presence ofplasma from women with PE was curtailed in the presenceof serum treated with the sflt-1 antibody, indicating thatVEGF may play a role in PE pathogenesis. PE has been asso-ciated with increased levels of sflt-1, possibly acting toreduce ligand binding to transmembrane receptors andinterfering with downstream signalling pathways [237].

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Therefore, sflt-1 may be depleting the placenta of necessaryamounts of essential angiogenic and mitogenic factors. Inthe invention in WO2004008946 [237] compounds adminis-tered that increase the levels of VEGF and placental growthfactor (PIGF) and counter the effects of elevated sflt-1 areproposed. In addition antibodies directed to sflt-1 could beused to competitively inhibit binding of VEGF or PIGF tosflt-1, thereby increasing the levels of free VEGF and PIGF.Furthermore RNA interference could also be used todecrease levels of sflt-1 [237].

Cytokines provide an important communication system incoordinating immune and inflammatory responses. Amongthe cytokines are a number of colony-stimulating factors(CSFs) including macrophage-CSF (M-CSF). Other cytokinesinclude the interleukins, which are known to possess varyingactivities, including being involved in hematopoiesis, and pro-viding defences against pathogenic infections. Cytokines areproduced in the uterus and placenta during normal pregnancy[100]. In rats, it has been observed that uterine gland cellssecrete M-CSF and the levels increased ∼ 1000-fold in the firstfew days of pregnancy [101]. In humans, the expression andlocalisation of mRNA for M-CSF have been demonstrated inmesenchymal cells of the chorionic villous stroma, particularlyin cytotrophoblasts lining the villous core and in the cytotro-phoblastic core in the first trimester, in villous mesenchymalcells in the second trimester, and in cells lining the villous ves-sels in the third trimester [102]. Circulating levels of macro-phage M-CSF during pregnancy are also higher compared tothose of non-pregnant women [103]. In apparently normalpregnancies with good outcomes, M-CSF levels rise through-out pregnancy with no cases of PE occurring if maternal serumM-CSF levels increase more than 100% throughout pregnancy[104]. Accordingly, an invention providing methods of increas-ing levels of circulating cytokines, particularly CSFs such asM-CSF, interleukins such as IL-11, and growth factors such asTNF-α, has been presented [238].

6. Modulators of trophoblast invasion

Page [105] first noted that placenta from women with PEappeared to be poorly perfused. Today it is known that aconsistent feature associated with this poor perfusion is thedefective trophoblast invasion of the myometrial portion ofthe spiral arteries. In normal pregnancy, trophoblast invasionof the spiral arteries renders them dilated, flaccid andunresponsive to vasoconstrictive agents, but if a defectiveinvasion occurs the spiral arteries retain their musculo-elasticproperties and responsiveness to vasoactive substances leadingto placental ischaemia.

A number of inventors have defined components thatendogenously regulate trophoblast invasion. PatentUS6376199 [239] describes antisense disruption of theexpression of the TGF-β3 receptor, endoglin, that triggersinvasion of cytotrophoblasts from first trimester villousexplants. This indicates that the TGF-β3 receptor system,

and in particular endoglin, plays a critical role in regulatingthis process. In particular, the presence of TGF-β3 and itsreceptors at 5 – 8 weeks at a time when there is no spontane-ous trophoblast invasion, and the absence of these moleculesat 12 – 13 weeks when spontaneous invasion occurs, estab-lishes a major role for TGF-β3 as an endogenous inhibitorof trophoblast invasion. The effects of antisense treatment toTGF-β3 are specific, as they are prevented by addition ofexogenous TGF-β3 but not TGF-β1 or TGF-β2. The clini-cal importance of TGF-β3 in regulating trophoblast inva-sion has been highlighted by the finding that TGF-β3 ishighly expressed in trophoblast tissue of PE patients whencompared to that in age-matched control placenta, whereasthere was no change in the expression of either the TGF-β1or -β2 isoforms. Furthermore, oxygen tension is also foundto play a role in regulating trophoblast invasion. The expres-sion of the hypoxia-inducible factor, (HIF)-1α, parallels that ofTGF-β3 in first trimester trophoblast by peaking at 6 – 8 weeksand decreasing after 9 – 10 weeks when oxygen tensionincreases. Again, expression of HIF-1α was dramaticallyincreased in placentae of PE patients when compared to age-matched control tissue. Induction of HIF-1α is found toupregulate TGF-β3 transcription and block trophoblast inva-sion. If this system fails to be downregulated at 9 – 11 weeks,shallow invasion is predicted, causing predisposition to PE.Therefore, methods of regulating trophoblast invasion byinhibiting or stimulating TGF-β3 receptors, HIF-1α and O2

tensions have been claimed [239].A striking feature of PE pregnancies is that expression of the

human leukocyte antigen (HLA)-G is reduced in term placen-tae compared with normal pregnancy. HLA-G modulatesinnate immunity by binding to several natural killer and/ordecidual receptors, inducing particular cytokine secretion,whilst soluble HLA-G downregulates endothelial cell prolifera-tion and migration. It is possible that defective HLA-G func-tion may contribute to the low trophoblast invasion andvascular abnormalities observed in PE placentae [106,240].Patent WO9943851 [240] therefore suggests treatment of PEwith a pharmaceutically-effective amount of HLA-G proteinor peptides that mimic or regulate the levels of HLA-G. Thisalso includes the exposure to fetal antigens including HLA-Gin the first pregnancy. This is because primigravid women havebeen estimated to be as much as six to eight times moresusceptible to developing PE [107] and represent up to 75% ofall cases of PE. A popular hypothesis to the cause of PE isimmune maladaption. It may be that HLA-G is capable ofprotecting susceptible target cells from natural killer-cell-medi-ated lysis. Thus, PE is likely to arise through a mechanism inwhich interaction between the T cells of the female matingpartner and fetal antigens is compromised in comparison tonormal pregnancy. A compromised interaction could lead to alack of stimulation of cells expressing HLA-G [240].

Syncytin, a protein encoded by the envelope gene of arecently identified human endogenous defective retrovirus,HERV-W, is highly expressed in placental tissue. Here, the

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major site of syncytin expression is the placental syncytio-trophoblast, a fused multinuclear syncytium originating fromcytotrophoblast cells. In PE, syncytin gene expression levelsare dramatically reduced [108]. Additionally, immunohisto-chemical examination of normal placentae and placentae fromwomen with PE reveals that the syncytin protein in placentaltissue from women with PE is localised improperly to the api-cal syncytiotrophoblast microvillous membrane as opposed toits normal location on the basal syncytiotrophoblast cytoplas-mic membrane. Lee et al. (2002) [108] have suggested that syn-cytin may mediate placental cytotrophoblast fusion in vivoand may play an important role in human placental morpho-genesis. Consequently, altered expression of the syncytin gene,and altered cellular location of its protein product, may con-tribute to the aetiology of PE [108]. Modulators of syncytincould provide a method for treating PE. Optionally, M-CSFand/or a TNF-α inhibitor could also be given to enhance thisresponse, or a therapy could be given that increases theexpression of syncytin [241]. By modulating the concentrationsof the various cytokines this may help to rectify the shallowplacentation described in PE.

7. Conclusions

The aetiology of PE is unknown and this has lead to confusionand controversy in both its diagnosis and therapy options. Adiverse range of symptoms and variability in different popula-tions further complicates this, set against a host of general andspecific risk factors. Much has been learned of the conditionrecently; the important role of correct trophoblast invasion ofthe placental bed, the ensuing placental and endothelial dys-function, and the resultant oxidative stress and general mater-nal inflammatory state. Many of the current leads for futuredrug development are illustrated in this review. However, cur-rent research needs to focus on the primary causes of the dis-ease, whilst bearing in mind the need to tackle the manysecondary features. It may be that one line of therapy alonewill emerge as a panacea for PE, however, it is increasinglyapparent that a diverse range of options is needed.

8. Expert opinion

Up to the present time, no drug therapy has addressed eitherthe targeting or lowering of the risk factors responsible for thedevelopment of the initial stages of PE. It is interesting to findproposals to redress this issue in the patent literature, as theimplantation of the placenta remains at the crux of PE pathol-ogy. Nevertheless, there may be dangers in unwittingly attempt-ing to control this finely-tuned and complex mechanism – aninvasive process compared to a controlled cancer growth.Therefore, most current therapy proposals are designed to tar-get the secondary features of the disease, mainly the clinicalsymptoms particularly those associated with hypertension andeclamptic seizures. Therefore, most emphasis has been placedon the development of the antihypertensive and the

anticonvulsant drugs. Their development as novel therapeuticsin PE stems mainly from their pre-existing use in treating eitheressential hypertension or epileptic seizures in the non-pregnantpopulation. Hence, there are many proposed modifications toalready established compounds, such as the ET antagonists, toincrease their bio-availability and reduce potential side effects.However, it is expected to be unlikely that the development ofnew antihypertensive drugs for PE will be able to target the pri-mary cause of the disease, as hypertension is only viewed as asecondary response. Indeed, antihypertensive therapy may evenaggravate the disease, by modulating the changes in blood pres-sure, giving the impression that the disease is being controlled.It is anticipated that broader spectrum drugs that not onlytarget hypertension but also the inflammation, eclampsia andendothelial dysfunction may be more favourable.

It is encouraging to find the discovery of new placental fac-tors, such as NKB, and to learn of autoimmune antibodiesthat may be responsible for activating vasoactive receptors.This provides an opportunity for the exploration of new ave-nues. Other interesting developments are the identificationand proposed use of naturally-occurring bio-metabolites.These include the use of the antihypertensive phosphocholi-nate cardenolides and the NO precursor L-citrulline. Both arecited as preferred for use in pregnancy, as degradation isexpected to occur by a natural metabolic pathway with lesspotential to form toxic metabolites. Ultimately, the therapeu-tic goal of each target will be to reduce the maternal risk inPE, with all agents selected being both efficacious and safe forthe fetus, especially in their acute and long-ranging neurologi-cal effects. Therefore, a careful balance of drugs needs to beprescribed so as not to compromise either the mother or fetus,and to maintain the pregnancy for as long as is safely possible.

It is notable that all of the patents quoted in this reviewproposing promising future directions for the treatment of PEhave not yet been explored, to the authors knowledge, in clin-ical trials. Therefore, no specific examples of their overalleffectiveness in PE can be gauged at the present time. Theclaims from many of the patents still remain only the basis ofprimary research papers. They are often founded on the pat-enting of the discovery of changing pathological levels of anendogenous compound, whereby the invention proposes abroad spectrum of modulating agents to correct this change.Frequently, no specific pharmacology or specific compoundsare identified with most preliminary drug testing being per-formed in an induced animal model. It is perhaps not difficultto judge the reasons for this, firstly the complex nature of PEand secondly the reluctance of pharmaceutical companies toindulge in clinical trails of new drugs during pregnancy. It canonly be hoped that by a careful balance of ethics and drugevaluation that some of these targets will be given anopportunity to reach the clinic in the future.

Acknowledgements

The Medical Research Council (UK) supported this work.

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BibliographyPapers of special note have been highlighted as either of interest (•) or of considerable interest (••) to readers.

1. DEPARTMENT OF HEALTH: Why mothers die: Report on confidential inquiries into maternal deaths in the United Kingdom 1994 – 1996. London: Stationary Office (1998).

2. VAUGHAN JP & ABOUZAHR C: Reproductive health: widening horizons. Int. J. Public Health (2000) 78:569.

3. NATIONAL INSTITUTES OF HEALTH: Working group report on high blood pressure in pregnancy. NIH publication. (2000) No. 00-3029 July, Bethsada.

4. CUNNINGHAM FG, TWICKLER D: Cerebral edema complicating eclampsia. Am. J. Obstet. Gynecol. (2000) 182:94-100.

5. THOMAS SV: Neurological aspects of eclampsia. J. Neurol. Sci. (1998) 1565:37-43.

6. SHEEHAN HL, LYNCH JB: Pathology of toxaemia of pregnancy. Churchill, Livingstone, London (1973).

7. LINDHEIMER MB, KATZ AI: Renal physiology and disease in pregnancy. In: The Kidney: Physiology and Pathophysiology, 2nd edition. Seldin DW & Giebisch G (Eds) Raven Press, New York (1992).

8. DAVISON JM: Edema in pregnancy. Kidney Int. Suppl. (1997) 59:S90-S96.

9. PRITCHARD JA, CUNNINGHAM FG, PRITCHARD SA, MASON RA: How often does maternal preeclampsia-eclampsia incite thrombocytopenia in the fetus? Obstet. Gynecol. (1987) 69:292-295.

10. BARRON WM, HECKERLING P, HIBBARD JU, FISHER S: Reducing unnecessary coagulation testing in hypertensive disorders of pregnancy. Obstet. Gynecol. (1999) 94:364-370.

11. WEINSTEIN L: Syndrome of hemolysis, elevated liver enzymes, and low platelet count: a severe consequence of hypertension in pregnancy. Am. J. Obstet. Gynecol. (1982) 142:159-167.

12. MARTIN JN, RINEHART BK, MAY WL, MAGANN EF, TERRONE DA, BLAKE PG: The spectrum of severe preeclampsia: comparative analysis by HELLP (hemolysis, elevated liver enzyme levels, and low platelet count) syndrome classification. Am. J. Obstet. Gynecol. (1999) 180:1373-1384.

13. ESKENAZI B, FENSTER L, SIDNEY S: A multivariate analysis of risk factors for preeclampsia. JAMA. (1991) 266:237-241.

14. DEKKER GA, DE VRIES JI, DOELITZSCH PM et al.: Underlying disorders associated with severe early-onset preeclampsia. Am. J. Obstet. Gynecol. (1995) 173:1042-1048.

15. SIBAI BM, GORDON T, THOM E et al.: Risk factors for preeclampsia in healthy nulliparous women: a prospective multicenter study. Am. J. Obstet. Gynecol. (1995) 172:642-648.

16. PAGE NM, KEMP CF, LOWRY PJ: Emerging molecular targets for the treatment of pre-eclampsia. Expert Opin Ther Targets. (2001)5(3):395-413.

17. WALKER JJ: Pre-eclampsia. Lancet. (2000) 356(9237):1260-1265.

• Highlights the current situation of antihypertensive drugs used to treat PE.

18. LYDAKIS C, LIP GY, BEEVERS M, BEEVERS DG: Atenolol and fetal growth in pregnancies complicated by hypertension. Am. J. Hypertens. (1999) 12(6):541-547.

19. SIBAI, BM, GROSSMAN RA, GROSSMAN HE: Effects of diuretics on plasma volume in pregnancies with long term hypertension. Am J. Obstet. Gynecol. (1984) 150(7):31-835.

20. HANSSENS M, KEIRSE MJ, VANKELECOM F, VAN ASSCHE FA: Fetal and neonatal effects of treatment with angiotensin-converting enzyme inhibitors in pregnancy. Obstet. Gynecol. (1991) 78(1):128-135.

21. SELIGMAN SP, BUYON JP, CLANCY RM, YOUNG BK, ABRAMSON SB: The role of nitric oxide in the pathogenesis of preeclampsia. Am. J. Obstet. Gynecol. (1994) 171(4):944-948.

22. VANHOUTTE PM, RUBANYI GM, MILLER VM, HOUSTON DS: Modulation of vascular smooth muscle contraction by the endothelium. Ann. Rev. Physiol. (1986)48:307-20.

23. KIMURA S, KASUYA Y, SAWAMURA T et al.: Conversion of big endothelin-1 to 21-residue endothelin-1 is essential for expression of full vasoconstrictor activity: structure–activity relationships of big endothelin-1. J. Cardiovasc. Pharmacol. (1989) 13(Suppl.5):S5-S57.

24. SAWAMURA T, KASUYA Y, MATSUSHITA Y et al.: Phosphoramidon inhibits the intracellular conversion of big endothelin-1 to endothelin-1 in cultured endothelial cells. Biochem. Biophys. Res. Commun. (1991) 174(2):779-784.

25. WOLFF K, NISELL H, CARLSTROM K et al.: Endothelin-1 and big endothelin-1 levels in normal term pregnancy and in preeclampsia. Regul. Pept. (1996) 67(3):211H216.

26. CLARK BA, HALVORSON L, SACHS B, EPSTEIN FH: Plasma endothelin levels in preeclampsia: elevation and correlation with uric acid levels and renal impairment. Am. J. Obstet. Gynecol. (1992) 166(3):962-968.

27. AJNE G: WOLFF K, FYHRQUIST F, CARLSTROM K, NISELL H, HEMSENHMORTBERG A: Endothelin converting enzyme (ECE) activity in normal pregnancy and preeclampsia. Hypertens. Pregnancy (2003) 22(3):215H224.

28. OLSON GL, SAADE GR, BUHIMSCHI I, CHWALISZ K, GARFIELD RE: The effect of an endothelin antagonist on blood pressure in a rat model of preeclampsia. Am. J. Obstet. Gynecol. (1999) 181(3):638-641.

29. LIAO QP, BUHIMSCHI IA, SAADE G, CHWALISZ K, GARFIELD RE: Regulation of vascular adaptation during pregnancy and post-partum: effects of nitric oxide inhibition and steroid hormones. Hum. Reprod. (1996) 11(12):2777-2784.

30. AHN K, SISNEROS AM, HERMAN SB et al.: Novel selective quinazoline inhibitors of endothelin converting enzyme-1. Biochem. Biophys. Res. Commun. (1998) 243(1):184-190.

31. PATT WC, CHENG XM, REPINE JT et al.: Butenolide endothelin antagonists with improved aqueous solubility. J. Med. Chem. (1999) 42(12):2162-2168.

32. TAYLOR RN, VARMA M, TENG NN, ROBERTS JM: Women with preeclampsia have higher plasma endothelin levels than women with normal pregnancies. J. Clin. Endocrinol Metab. (1990) 71(6):1675-1677.

33. HALIM A, KANAYAMA N, EL MARADNY E et al.: Eclampsia-like seizures and electroencephalographic changes in pregnant rabbits with endothelin-1 injections. Gynecol. Obstet. Invest. (1995) 39(1):1-7.

Exp

ert O

pin.

The

r. P

aten

ts D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y C

olor

ado

Stat

e U

nive

rsity

on

08/2

4/14

For

pers

onal

use

onl

y.

Page


34. HALIM A, KANAYAMA N, EL MARADNY E, MAEHARA K, BHUIYAN AB, TERAO T: Correlated plasma elastase and sera cytotoxicity in eclampsia. A possible role of endothelin-1 induced neutrophil activation in preeclampsia-eclampsia. Am. J. Hypertens. (1996) 9(1):33-38.

35. AJNE G, NISELL H: WOLFF K, JANSSON T: The role of endogenous endothelin in the regulation of uteroplacental and renal blood flow during pregnancy in conscious rats. Placenta (2003) 8-9:813-818.

36. TANIGUCHI T, MURAMATSU I: Pharmacological knockout of endothelin ET(A) receptors. Life Sci. (2003) 74(2-3):405-409.

37. MADSEN KM, NEERHOF MG, WESSALE JL, THAETE LG: Influence of ET(B) receptor antagonism on pregnancy outcome in rats. J. Soc. Gynecol. Investig. (2001) 8(4):239-244.

38. CERVAR M, PUERSTNER P, KAINER F, DESOYE G: Endothelin-1 stimulates the proliferation and invasion of first trimester trophoblastic cells in vitro-a possible role in the etiology of pre-eclampsia? J. Investig. Med. (1996) 44(8):447-453.

39. BROUGHTON PIPKIN F, SYMONDS EM: Factors affecting factor angiotensin II concentrations in the human infant at birth. Clin. Sci. Mol. Med. (1977) 52:449-456.

40. HANSSENS M, KEIRSE MJ, SPITZ B, VAN ASSCHE FA: Angiotensin II levels in hypertensive and normotensive pregnancies. Br. J. Obstet. Gynaecol. (1991) 98:155-161.

41. ITO M, ITAKURA A, OHNO Y et al.: Possible activation of the renin-angiotensin system in the feto-placental unit in preeclampsia. J. Clin. Endocrinol. Metab. (2002) 87(4):1871-1878.

42. BROWN MA, WANG J, WHITWORTH JA: The renin-angiotensin-aldosterone system in pre-eclampsia. Clin. Exp. Hypertens. (1997) 19(5-6):713-726.

43. WALLUKAT G, HOMUTH V, FISCHER T et al.:. Patients with preeclampsia develop agonistic autoantibodies against the angiotensin AT1 receptor. J. Clin. Invest. (1999) 103(7):945-952.

44. HANSSENS M, KEIRSE MJ, VANKELECOM F, VAN ASSCHE FA: Fetal and neonatal effects of treatment with angiotensin-converting enzyme inhibitors in pregnancy. Obstet. Gynecol. (1991) 78(1):128-135.

45. WIMALAWANSA SJ, YALLAMPALLI C: Pre-eclamptic toxemia: potential new therapy based on animal studies. Ceylon Med. J. (1998) 43(3):138-146.

46. D’ORLEANS-JUSTE P, CLAING A, TELEMAQUE S, WARNER TD, REGOLI D: Neurokinins produce selective venoconstriction via NK-3 receptors in the rat mesenteric vascular bed. Eur. J. Pharmacol. (1991) 204:329-334.

47. MASTRANGELO D, MATHISON R, HUGGEL HJ et al.: The rat isolated portal vein: a preparation sensitive to neurokinins, particularly neurokinin B. Eur. J. Pharmacol. (1987) 134:321-326.

48. THOMPSON GW, HOOVER DB, ARDELL JL, ARMOUR JA: Canine intrinsic cardiac neurons involved in cardiac regulation possess NK1, NK2 and NK3 receptors. Amer. J. Physiol. Regul. Integrat. Comp. Physiol. (1998) 44:1683-1689.

49. ROCCON A, MARCHIONNI D, NISATO D: Study of SR 142801, a new potent non-peptide NK3 receptor antagonist on cardiovascular responses in conscious guinea-pig. Br. J. Pharmacol. (1996) 118(5):1095-1102.

50. PAGE NM: WOODS RJ, GARDINER SM et al.: Excessive placental secretion of neurokinin B during the third trimester causes pre-eclampsia. Nature. (2000) 405(6788):797-800.

51. BROWNBILL P, BELL NJ: WOODS RJ, LOWRY PJ, PAGE NM, SIBLEY CP: Neurokinin B is a paracrine vasodilator in the human fetal placental circulation. J. Clin. Endocrinol. Metab. (2003) 88(5):2164-2170.

52. LALIBERTE C, DIMARZO L, MORRISH DW, KAUFMAN S: Neurokinin B causes concentration-dependent relaxation of isolated human placental resistance vessels. Regul. Pept. (2004) 117(2):123-126.

53. PINTADO CO, PINTO FM, PENNEFATHER JN et al.: A role for tachykinins in female mouse and rat reproductive function. Biol. Reprod. (2003) 69(3):940-946.

54. KAMINSKI K, RECHBERGER T: Concentration of digoxin-like immunoreactive substance in patients with preeclampsia and its relation to severity of pregnancy-induced hypertension. Am. J. Obstet. Gynecol. (1991) 165(3):733-736.

55. ADAIR CD, BUCKALEW V, TAYLOR K et al.: Elevated endoxin-like factor complicating a multifetal second trimester pregnancy: treatment with digoxin-binding immunoglobulin. Am. J. Nephrol. (1996) 16(6):529-531.

56. TYMIAK AA, NORMAN JA, BOLGAR M et al.: Physicochemical characterization of a ouabain isomer isolated from bovine hypothalamus. Proc. Natl. Acad. Sci. USA (1993) 90(17):8189-8193.

57. SOMOGYI J, SZALAY J, PANDICS T, ROSTA K, CSERMELY P, VER A: New steroid hormone family: endogenous cardiac glycosides and their role in physiologic and pathologic conditions. Orv. Hetil. (2004) 145(6):259-266.

58. LOPATIN DA, AILAMAZIAN EK, DMITRIEVA RI et al.: Circulating bufodienolide and cardenolide sodium pump inhibitors in preeclampsia. J. Hypertens. (1999) 17(8):1179-1187.

59. FURUHASHI N, TSUJIEI M, KIMURA H, OKAMURA K, YAJIMA A: Antithromboxane drug in the treatment of preeclampsia. Gynecol. Obstet. Invest. (1991) 32(3):164-166.

60. SEKI H, KUROMAKI K, TAKEDA S, KINOSHITA K, SATOH K: Trial of prophylactic administration of TXA2 synthetase inhibitor, ozagrel hydrochloride, for preeclampsia. Hypertens. Pregnancy (1999) 18(2):157-164.

61. SULLIVAN MH, AHMED Y, ELDER MG: Effects of a thromboxane synthetase inhibitor on platelet function; possible risks of use in pregnancy. Prostaglandins (1993) 46(1):21-26.

62. ZLATNIK MG, BUHIMSCHI I, CHWALISZ K, LIAO QP, SAADE GR, GARFIELD RE: The effect of indomethacin and prostacyclin agonists on blood pressure in a rat model of preeclampsia. Am. J. Obstet. Gynecol. (1999) 180(5):1191-1195.

63. FERRAZZANI S, DE SANTIS L, CARDUCCI B et al.: Prostaglandin: cervical ripening in hypertensive pregnancies. Acta. Obstet. Gynecol. Scand. (2003) 82(6):510-515.

64. SHAAMASH AH, ELSNOSY ED, MAKHLOUF AM, ZAKHARI MM, IBRAHIM OA, EL-DIEN HM: Maternal and fetal serum nitric oxide (NO) concentrations in normal pregnancy, pre-eclampsia and eclampsia. Int. J. Gynaecol. Obstet. (2000) 68(3):207-214.

Exp

ert O

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The

r. P

aten

ts D

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08/2

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65. BUHIMSCHI IA, SAADE GR, CHWALISZ K, GARFIELD RE: The nitric oxide pathway in pre-eclampsia: pathophysiological implications. Hum. Reprod. Update (1998) 4(1):25-42.

66. MURAD F: Regulation of cytosolic guanylyl cyclase by nitric oxide: the NO-cyclic GMP signal transduction system. Adv. Pharmacol. (1994) 26:19-33.

67. BENYO Z, GORLACH C, WAHL M: Involvement of thromboxane A2 in the mediation of the contractile effect induced by inhibition of nitric oxide synthesis in isolated rat middle cerebral arteries. J. Cereb. Blood Flow Metab. (1998) 18(6):616-618.

68. WANG W, DIAMOND SL: Does elevated nitric oxide production enhance the release of prostacyclin from shear stressed aortic endothelial cells? Biochem. Biophys. Res. Commun. (1997) 28;233(3):748-751.

69. GUDE NM, BOURA AL, KING RG et al: Evidence for inhibition by endothelium-derived relaxing factor of thromboxane A2 receptor-mediated vasoconstriction in the fetal vessels of the human perfused placenta. Placenta (1992) 13(6):597-605.

70. YALLAMPALLI C, GARFIELD RE: Inhibition of nitric oxide synthesis in rats during pregnancy produces signs similar to those of preeclampsia. Am. J. Obstet. Gynecol. (1993) 169(5):1316-1320.

• Inhibition of nitric oxide synthesis in rats provides an animal model for the study of PE.

71. HELMBRECHT GD, FARHAT MY, LOCHBAUM L et al.: L-arginine reverses the adverse pregnancy changes induced by nitric oxide synthase inhibition in the rat. Am. J. Obstet. Gynecol. (1996) 175(4 Pt.1):800-805.

72. RICHER C, BOULANGER H, ES-SLAMI S, GIUDICELLI JF: Lack of beneficial effects on the NO-donor, molsidomine, in the L-NAME-induced pre-eclamptic syndrome in pregnant rats. Br. J. Pharmacol. (1996) 119(8):1642-1648.

73. GONZALEZ C, CRUZ MA, GALLARDO V, MIGUEL P, CARRASCO G: Relative potency of nitrovasodilators on human placental vessels from normal and preeclamptic pregnancies. Gynecol Obstet Invest. (1997) 43(4):219-224.

74. LUZI G, CASERTA G, IAMMARINO G, CLERICI G, DI RENZO GC: Nitric oxide donors in pregnancy: fetomaternal hemodynamic effects induced in mild pre-eclampsia and threatened preterm labor. Ultrasound Obstet. Gynecol. (1999) 14(2):101-109.

75. LEES C, LANGFORD E, BROWN AS et al.: The effects of S-nitrosoglutathione on platelet activation, hypertension, and uterine and fetal Doppler in severe preeclampsia. Obstet. Gynecol. (1996) 88(1):14-19.

76. AHOKAS RA, MERCER BM, SIBAI BM: Enhanced endothelium-derived relaxing factor activity in pregnant, spontaneously hypertensive rats. Am. J. Obstet. Gynecol. (1991) 165:801-807.

77. HOBBS AJ: Soluble guanylate cyclase: the forgotten sibling. Trends Pharmacol. Sci. (1997) 18(12):484-491.

78. SELWOOD DL, BRUMMELL DG, BUDWORTH J et al.: Synthesis and biological evaluation of novel pyrazoles and indazoles as activators of the nitric oxide receptor, soluble guanylate cyclase. J. Med. Chem. (2001) 44(1):78-93.

79. HECKER M, SESSA WC, HARRIS HJ, ANGGARD EE, VANE JR: The metabolism of L-arginine and its significance for the biosynthesis of endothelium-derived relaxing factor: cultured endothelial cells recycle L-citrulline to L-arginine. Proc. Natl. Acad. Sci.: USA (1990) 87(21):8612-8616.

80. ANDERSON TW, NERI LC, SCHREIBER GB, TALBOT FD, ZDROJEWSKI A: Letter: ischemic heart disease, water hardness and myocardial magnesium. Can. Med. Assoc. J. (1975) 113(3):199-203.

81. MOTOYAMA T, SANO H, FUKUZAKI H: Oral magnesium supplementation in patients with essential hypertension. Hypertension (1989) 13(3):227-232.

82. MAKRIDES M, CROWTHER CA: Magnesium supplementation in pregnancy. Cochrane Database Syst. Rev. (2001) 4:CD000937.

83. CONRADT A, WEIDINGER H, ALGAYER H: Reduced frequency of gestoses in β-mimetic treated risk pregnancies with added magnesium therapy. Geburtshilfe Frauenheilkd (1984) 44(2):118-123.

84. SIBAI BM, VILLAR MA, BRAY E: Magnesium supplementation during pregnancy: a double-blind randomized controlled clinical trial. Am. J. Obstet. Gynecol. (1989) 161(1):115-119.

85. MAGPIE TRIAL COLLABORATION GROUP: Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial: a randomised placebo-controlled trial. Lancet. (2002) 359(9321):1877-1890.

86. MCCARTY MF: Magnesium taurate for the prevention and treatment of pre-eclampsia/eclampsia. Med. Hypotheses (1996) 47(4):269-272.

87. MOODLEY J, RAMPERSADH S, BECKER P, NORMAN RJ, O’DONELL D: Serum calcium ion concentrations in eclampsia. S. Afr. Med. J. (1987) 19;72(6):382-385.

88. LOPEZ-JARAMILLO P: Calcium, nitric oxide, and preeclampsia. Semin. Perinatol. (2000) 24(1):33-36.

89. BUCHER HC, GUYATT GH, COOK RJ et al.: Effect of calcium supplementation on pregnancy-induced hypertension and preeclampsia: a meta-analysis of randomized controlled trials. JAMA. (1996) 10;275(14):1113-1117.

90. MORRIS CD, JACOBSON SL, ANAND R et al.: Nutrient intake and hypertensive disorders of pregnancy: evidence from a large prospective cohort. Am. J. Obstet. Gynecol. (2001) 184(4):643-651.

91. WELLS IC, AGRAWAL DK, ANDERSON RJ: Abnormal magnesium metabolism in etiology of salt-sensitive hypertension and Type 2 diabetes mellitus. Biol. Trace Elem. Res. (2004) 98(2):97-108.

92. SAVELIEVA GM, EFIMOV VS, GRISHIN VL, SHALINA RI, KASHEZHEVA AZ: Blood coagulation changes in pregnant women at risk of developing preeclampsia. Int. J. Gynaecol. Obstet. (1995) 48(1):3-8.

93. ROBERTS JM, TAYLOR RN, MUSCI TJ, RODGERS GM, HUBEL CA, MCLAUGHIN MK: Preeclampsia: an endothelial cell disorder. Am. J. Obstet. Gynecol. (1989)161:1200-1204.

• Landmark paper describing the important role of endothelial cell dysfunction in PE.

94. BAKER PN, KRASNOW J, ROBERTS JM, YEO KT: Elevated serum levels of vascular endothelial growth factor in patients with preeclampsia. Obstet. Gynecol. (1995) 86(5):815-821.

• First report of elevated levels of vascular endothelial growth factor in PE.

95. KUPFERMINC MJ, DANIEL Y, ENGLENDER T et al.: Vascular endothelial growth factor is increased in patients with preeclampsia. Am. J. Reprod. Immunol. (1997) 38(4):302-306.

Exp

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96. SHARKEY AM, COOPER JC, BALMFORTH JR et al.: Maternal plasma levels of vascular endothelial growth factor in normotensive pregnancies and in pregnancies complicated by pre-eclampsia. Eur. J. Clin. Invest. (1996) 26(12):1182-1185.

97. LYALL F, GREER IA, BOSWELL F, FLEMING R: Suppression of serum vascular endothelial growth factor immunoreactivity in normal pregnancy and in pre-eclampsia. Br. J. Obstet. Gynaecol. (1997) 104(2):223-228.

98. LYALL F, YOUNG A, BOSWELL F, KINGDOM JC, GREER IA.: Placental expression of vascular endothelial growth factor in placentae from pregnancies complicated by pre-eclampsia and intrauterine growth restriction does not support placental hypoxia at delivery. Placenta (1997) 18(4):269-276.

99. COOPER JC, SHARKEY AM, CHARNOCK-JONES DS, PALMER CR, SMITH SK: VEGF mRNA levels in placentae from pregnancies complicated by pre-eclampsia. Br. J. Obstet. Gynaecol. (1996) 103(12):1191-1196.

100. TABIBZADEH S: Human endometrium: an active site of cytokine production and action. Endocr. Rev. (1991) 12(3):272-290.

101. POLLARD JW, BARTOCCI A, ARCECI R, ORLOFSKY A, LADNER MB, STANLEY ER: Apparent role of the macrophage growth factor, CSF-1, in placental development. Nature (1987) 330(6147):484-486.

102. DAITER E, PAMPFER S, YEUNG YG, BARAD D, STANLEY ER, POLLARD JW: Expression of colony-stimulating factor-1 in the human uterus and placenta. J. Clin. Endocrinol. Metab. (1992) 74(4):850-858.

103. YONG K, SALOOJA N, DONAHUE RE, HEGDE U, LINCH DC: Human macrophage colony-stimulating factor levels are elevated in pregnancy and in immune thrombocytopenia. Blood (1992) 80(11):2897-2902.

104. KEITH JC JR, PIJNENBORG R, LUYTEN C, SPITZ B, SCHAUB R, VAN ASSCHE FA: Maternal serum levels of macrophage colony-stimulating factor are associated with adverse pregnancy outcome. Eur. J. Obstet. Gynecol. Reprod. Biol. (2000) 89(1):19-25.

105. PAGE EW: The relation between hydatid moles, relative ischemia of the gravid uterus, and the placental origin of eclampsia. Am. J. Obstet. Gynecol. (1939) 37:291-293.

106. LE BOUTEILLER P, PIZZATO N, BARAKONYI A, SOLIER C: HLA-G, pre-eclampsia, immunity and vascular events. J. Reprod. Immunol. (2003) 59(2):219-234.

107. SURRATT N: Severe preeclampsia: implications for critical-care obstetric nursing. J. Obstet. Gynecol. Neonatal. Nurs. (1993) 22(6):500-507.

108. LEE X, KEITH JC JR, STUMM N et al.: Downregulation of placental syncytin expression and abnormal protein localization in pre-eclampsia. Placenta. (2001) 22(10):808-812.

Patents201. SCHERING AG; UNIV. TEXAS:

US5811416 (1998).

202. WARNER-LAMBERT CO.: WO9737987 (1997).

203. WARNER-LAMBERT CO.: US6133263 (2000).



206. THERAVANCE, INC.: NZ505887 (2003).


208. ONO PHARM. CO.: EP-579496 (1994).


210. WARNER-LAMBERT CO.: WO9428012 (1994).


212. MAX DELBRUECK CENTRUM: DE19954305 (2000).

213. ADVANCED MEDICINE, INC.; GRIFFIN JH, MARQUESS D, THOMAS GR: WO9963930 (1999).

214. UNIV. TEXAS: US5910482 (1999).

215. UNIV. READING: WO0136979 (2001).

216. ADAIR CD: US2004018201 (2004).

217. ADAIR CD: US2004018202 (2004).

218. LONG ISLAND JEWISH MEDICAL CT: US5028438 (1991).

219. CHASLOW FI; BRADLOW H LEON: US5122371 (1992).

220. KERIX LLC: US6177461 (2001).

221. APPLIED RES. SYSTEMS: WO03053923 (2003).



224. TEXAS A&M UNIV. SYST.; UNIV. TEXAS: US5869539 (1999).

225. ABRAHAM NG, MARTASEK P, LEVERE RD, SCHWARTZMAN ML: EP-0441119 (1991).

226. KING S COLLEGE LONDON; WELLCOME FOUND.: WO9617604 (1996).

227. SCHERING AG; UNIV. TEXAS: US5965529 (1999).

228. GARFIELD RE, YALLAMPALLI C; SCHERING AG: AU768406 (2003).

229. UNIV. LONDON; LIU Q: WO0027394 (2000).

230. CHWALISZ K, GARFIELD RE, SHI S-Q: US2001056068 (2001).

231. WAUGH WH: US5874471 (1999).

232. NUTRITION 21: US5776504 (1998).

233. MAGNESIUM DIAGNOSTICS, INC.: US6455734 (2002).

234. LAKARO BIOPHARM., INC.: EP-1016410 (2000).

235. JOHNSON RJ (US), SCHREINER GF: US2003220262 (2003).

236. TAP PHARM., INC.: US5534548 (1996).

237. BETH ISRAEL HOSP.: WO2004008946 (2004).

238. GENETICS INST.; VIRGINIA POLYTECHNIC INST.: US5580554 (1996).

239. MOUNT SINAI HOSP. CORP.;HOSP. FOR SICK CHILDREN HSC: US6376199 (2002).

240. UNIV. IRELAND CORK: WO9943851 (1999).

241. GENETICS INST.: WO0204678 (2002).

AffiliationDr Nigel M PageSchool of Animal and Microbial Sciences, University of Reading, Reading, RG6 6AJ, UKTel: +44 118 9875123; Fax: +44 118 9310180; E-mail: [email protected]

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Therapeutic patents for the treatment of pre-eclampsia