RESPIRATORY SYSTEM MALIGNANCY

Adipokines and Systemic Inflammation in Weight-Losing LungCancer Patients

Sule T. Gulen • Fisun Karadag • Aslihan B. Karul •

Naciye Kilicarslan • Emel Ceylan • Nilgun K. Kuman •

Orhan Cildag

Received: 3 October 2011 / Accepted: 22 December 2011 / Published online: 14 January 2012

� Springer Science+Business Media, LLC 2012

Abstract

Background Cancer cachexia is a devastating condition

leading to loss of function and independence, decreased per-

formance status, decreased quality of life, and poor prognosis.

Adipokines play a role in a wide variety of physiological or

pathological processes, including immunity and inflamma-

tion, in addition to having significant effects on metabolism

and lipogenesis. The objective of the present study was to

investigate the relationship of adipokines and systemic

inflammation in weight-losing advanced-stage non-small-cell

lung cancer (NSCLC) patients.

Methods Sixty-three male NSCLC patients (stages III and

IV) and 25 age- and sex-matched controls were included.

NSCLC patients were further divided into subgroups as those

with a [ 5% weight loss in last 6 months and those who did

not. Serum leptin, adiponectin, and TNF-a concentrations

were measured by ELISA using commercially available kits.

Results The positive acute-phase reactants (APR) CRP,

leukocyte, ferritin, thrombocyte, and fibrinogen were higher in

the NSCLC group. Serum albumin level (which is a negative

APR) was lower in the cancer group, whereas there was no

difference in transferrin level between the groups. TNF-a and

leptin concentrations were similar in the cancer group and the

control group, whereas adiponectin was lower in the cancer

group. There was a difference in thrombocyte and transferrin

levels between patients with and without weight loss, whereas

CRP, TNF-a, and adiponectin levels were similar. Leptin was

lower in weight-losing cancer patients. However, there was no

correlation between adipokines and markers of systemic

inflammation.

Conclusion These results revealed a lack of association

between adipokine levels and systemic inflammation with

cancer cachexia.

Keywords Adipokines � Lung cancer � Systemic

inflammation � Weight loss

Introduction

Cancer cachexia is a devastating condition leading to loss

of function and independence, decreased performance

status, decreased quality of life, and poor prognosis and

may account for up to 20% of cancer deaths [1, 2]. The

exact mechanisms of cancer cachexia remain unclear but

are almost certainly multifactorial. To a large degree

development of cancer cachexia is related to a chronic,

low-grade, tumor-induced activation of the host’s immune

system. The systemic inflammatory response, as evidenced

by elevated circulating concentrations of APP, including

C-reactive protein (CRP), and cytokines, including tumor

necrosis factor alpha (TNF-a), is shown to be an important

factor in the progressive nutritional decline of these

patients and is a poor prognostic factor independent of

stage, performance status, and treatment [2, 3].

White adipose tissue (WAT) is currently considered an

endocrine organ that is an active contributor to body

homeostasis rather than just being a fat depot, producing

S. T. Gulen � F. Karadag (&) � E. Ceylan � O. Cildag

Department of Chest Diseases, School of Medicine,

Adnan Menderes University, 09100 Aydin, Turkey

e-mail: fisunkaradag@yahoo.com

A. B. Karul � N. Kilicarslan

Department of Biochemistry, School of Medicine,

Adnan Menderes University, Aydin, Turkey

N. K. Kuman

Department of Thoracic Surgery, School of Medicine,

Adnan Menderes University, Aydin, Turkey

123

Lung (2012) 190:327–332

DOI 10.1007/s00408-011-9364-6

more than 50 cytokines and other molecules [4]. These

adipokines play a role in a wide variety of physiological or

pathological processes, including immunity and inflam-

mation, in addition to having significant effects on

metabolism and lipogenesis [5].

Leptin, the product of the ob gene, is a protein syn-

thesized and secreted mainly by WAT in proportion to fat

stores, and it is considered an adipokine that belongs to

the class I cytokine superfamily [4, 6]. It decreases food

intake and increases energy consumption by inducing

anorexigenic factors and suppressing orexigenic neuro-

peptides [4]. Leptin production is regulated mainly by

food intake; fasting reduces leptin levels while food

consumption is associated with a transient increase in ob

gene expression [6]. However, leptin levels can be influ-

enced by other factors as well. Leptin expression is

upregulated by various proinflammatory cytokines,

including TNF-a, IL-1, and IL-6 [7]. However, in contrast

to acute stimulation of the inflammatory system, chronic

inflammation causes a reduction in leptin levels [8].

Leptin has emerged in the literature as a multifunctional

hormone with versatile activities and complex counter-

actions with other cytokines and adipokines [6]. A

remarkable aspect of the effects of leptin on the immune

system is its action as a proinflammatory cytokine itself.

Leptin can therefore be described as a cytokine-like

hormone with pleiotropic actions [4].

Adiponectin, a protein produced largely by WAT,

increases fatty acid oxidation and reduces the synthesis of

glucose in the liver and its serum level is associated with

body mass index (BMI) and insulin resistance [4]. In

addition to its role in protection against obesity and

obesity-related disorders, adiponectin has a wide range of

effects in pathologies with inflammatory components.

Adiponectin exerts relevant actions on innate and adaptive

immunity and its secretion is inhibited by proinflamma-

tory cytokines such as IL-6 and TNF-a [9]. The objective

of the present study was to investigate the relationship of

adipokines and systemic inflammation in weight-losing

advanced-stage non-small-cell lung cancer patients.

Methods

Subjects

Sixty-three male lung cancer patients (age range = 52–84

years) were admitted to the study consecutively. All patients

were histopathologically confirmed to have NSCLC. None of

the patients had undergone surgical resection or had received

chemotherapy or radiotherapy at the time of sampling.

NSCLC patients were further divided into subgroups as those

with a [ 5% weight loss in preceding 6 months (n = 33) and

those who had not (n = 30). Twenty-five male volunteers,

participants at the Chest Diseases Outpatients Clinic, in the

same age range were admitted as the control group. Both

patients and controls with comorbidities that affect weight

maintenance (diabetes, thyroid dysfunction, alcoholism,

malabsorption, renal, and hepatic diseases) or that lead to

systemic inflammation (infection, heart failure, collagen

vascular diseases) and those who did not have precise infor-

mation on his body weight status in the preceding 6 months

were excluded from the study.

Staging of the NSCLC patients was established by

clinical findings, chest X-ray, bronchoscopy, thorax CT,

brain MR, and PET-CT on the basis of the latest TNM

staging system [10]. BMI was calculated as weight/height2

(kg/m2). The study was approved by the institutional ethics

committee and all subjects gave written consent to

participate.

Measurement of Acute-Phase Reactants, Cytokine,

and Adipokines

Fasting blood samples were collected for routine laboratory

analysis of acute-phase reactants (APR) between 8 and 10 a.m.

Another blood sample was taken and centrifuged at

4,0009g for 7 min at room temperature. The samples were

stored in aliquots at -80�C until analysis. Serum leptin

(pg/ml) and adiponectin (ng/ml) concentrations were mea-

sured by solid-phase sandwich enzyme-linked immunosor-

bent assay (ELISA) using Bender MedSystems Human Leptin

kit (No. BMS2039INST; Vienna, Austria) and BioVendor

Human Adiponectin kit (No. RD191023100, Candler, NC,

USA) according to the manufacturers’ instructions. Serum

TNF-a concentration (pg/ml) was also measured by ELISA

using a Bender MedSystems Human TNF-a kit (No.

BMS223INSTCE). Serum CRP concentration (mg/L) was

measured by a commercially available kit using the turbidi-

metric method (Prestige 24i, kit No. 81067HWOO, Tokyo

Boeiki, Tokyo, Japan).

Statistical Analysis

Statistical tests were done with the SPSS software program

(SPSS, Inc., Chicago, IL, USA). Results are given as

mean ± SD. Correlations between parameters were evalu-

ated using Pearson’s rank correlation analysis. Nonparametric

data of the study groups were compared by Mann–Whitney

U test. A significance level of P = 0.05 was used.

Results

Demographic data of the study groups and tumor charac-

teristics of NSCLC patients admitted to the study are given

328 Lung (2012) 190:327–332

123

in Table 1. The study groups were age- and sex-matched;

they were all male and the mean age was 65.63 ±

9.87 years for the NSCLC group and 63.52 ± 11.54 for the

control group. Thirty-three (52.4%) NSCLC patients had

weight loss in preceding 6 months. BMI of the NSCLC

group was lower than that of the controls (P = 0.026). The

smoking history of the groups was similar (P = 0.079).

Forty-three percent of NSCLC patients were classified as

stage III and 57% as stage IV.

The positive APR CRP, leukocyte, ferritin, thrombo-

cyte, and fibrinogen were higher in the NSCLC group.

Serum albumin (which is a negative APR) was lower in the

cancer group, whereas there was no difference in trans-

ferrin level between the groups. There were differences in

thrombocyte and transferrin levels between patients with

and without weight loss (Tables 2, 3).

Serum leptin, adiponectin, CRP, and TNF-a concentra-

tions of the study groups are given in Table 2. Adiponectin

concentrations were significantly lower in lung cancer

patients compared to controls (P = 0.020), whereas leptin

(P = 0.528) and TNF-a concentrations were similar in the

cancer group and the control group (P = 0.063).

There were 33 NSCLC patients (52.4%) who had lost

weight in the 6 months before entry into the study. The

comparison of leptin, adiponectin, CRP, and TNF-a concen-

trations in patients with and without weight loss are given in

Table 3. Serum leptin concentration was found to be lower in

the weight-losing group (P = 0.006). Adiponectin and CRP

concentrations were higher in weight-losing group but the

difference was not statistically significant (P = 0.700 and

P = 0.242, respectively). TNF-a concentrations were similar

in both subgroups (P = 0.094).

In correlation tests, CRP was correlated with transferrin

(r = -0.499, P \0.001), ferritin (r = 0.390, P = 0.004),

thrombocyte (r = 0.295, P = 0.019), and fibrinogen (r =

0.523, P\ 0.001) in NCSLC patients. There was a positive

correlation between leptin and BMI in NSCLC patients

(r = 0.473, P = 0.001). However, there was no correlation

between adipokines and markers of systemic inflammation

(APR and TNF-a) (P[ 0.05 for all).

Discussion

Cancer is a systemic inflammation where multiple cyto-

kines are involved. Systemic inflammation is driven by

proinflammatory cytokines, which exert their role on

catabolism, gluconeogenesis, and acute-phase protein pro-

duction [1]. Although these cytokines have a protective

role in the first steps of inflammation, the unlimited con-

tinuation of inflammation has deleterious effects resulting

in poor outcome in advanced cancer [1, 11].

Table 1 Demographic data of study groups and tumor characteristics

of NSCLC patients

NSCLC

(n = 63)

Controls

(n = 25)

P

Age (years) 65.63 ± 9.87 63.52 ± 11.54 0.063

Gender M/F (%) 100 100 –

Smoking

(pack-years)

63.84 ± 30.29 60.72 ± 27.34 0.079

Weight loss, n (%) 33 (52.4) 0 –

BMI (kg/m2) 23.51 ± 4.58 27.76 ± 3.90 0.026

Stage, n (%)

IIIa–IIIb 27 (43%) – –

IVa–IVb 36 (57%)

Data are mean ± SD

NSCLC non-small-cell lung carcinoma, BMI body mass index

Table 2 Acute-phase reactants,

cytokine, and adipokines in

NSCLC patients and controls

Values are mean ± SD

NSCLC non-small-cell lung

carcinoma, CRP C-reactive

protein, TNF-a tumor necrosis

factor a

NSCLC patients (n = 63) Controls (n = 25) P

Acute phase reactants

CRP (mg/l) 44.57 ± 36.09 6.10 ± 14.94 \0.001

Leucocyte (mkrL) 9815.87 ± 3166.67 8442.86 ± 1923.95 0.042

Thrombocyte (mkrL) 368936.51 ± 134528.43 243952.38 ± 104813.39 \0.001

Ferritin (ng/ml) 252.59 ± 212.40 110.31 ± 86.22 0.009

Fibrinogen (mg/dl) 436.13 ± 158.64 240.00 ± 93.26 \0.001

Albumin (g/dl) 4.26 ± 0.49 4.68 ± 0.41 \0.001

Transferrin (lg/dl) 178.71 ± 51.06 190.00 ± 38.21 0.339

Cytokine and adipokines

TNF-a (pg/ml) 5.50 ± 2.19 5.63 ± 1.54 0.063

Leptin (pg/ml) 187.46 ± 98.14 186.97 ± 66.95 0.528

Adiponectin (ng/ml) 51.70 ± 24.43 68.20 ± 29.82 0.020

Lung (2012) 190:327–332 329

123

Adipokines exert significant effects on metabolism and

lipogenesis as well as in regulation of human inflammatory

responses. Leptin suppresses food intake and stimulates

energy expenditure, while serum levels of adiponectin and

resistin are associated with BMI and insulin resistance [4,

5]. Moreover, they participate in the systemic inflammatory

response with strong reciprocal influences on other cyto-

kines like TNF-a, IL-10, and IL-6, regulating in this way

systemic inflammatory response and cell proliferation,

differentiation, and migration [4–9].

Besides systemic inflammation, advanced cancer is

associated with weight loss [12]. Cancer cachexia is a

complex metabolic status not very well elucidated.

Decreased food intake, hypermetabolism, and acute-phase

response with metabolic disturbances partly due to host and

tumor-derived substances, including various cytokines, and

are considered important wasting factors leading to loss of

skeletal mass and adipose tissue [11, 13]. Although adi-

pokines are strongly associated with BMI, their role in this

complicated situation is not clear.

Whether leptin acts as an acute-phase reactant leading to

anorexia and malnutrition, or if it is only a simple marker of fat

mass in cancer-associated malnutrition is not clear. Leptin

concentrations are increased during cytokine-induced

inflammatory response in sepsis patients, suggesting that

raised leptin levels may be related to anorexia [14]. However,

in many chronic diseases leading to cachexia, in which there is

also an inflammatory status caused by raised proinflammatory

cytokines, serum leptin levels are decreased. This is the case of

wasting associated with chronic obstructive pulmonary dis-

ease and chronic heart failure cachexia in which, despite an

increase in TNF-a and IL-1 levels, there are low leptin levels

that have a relationship with decreased fat mass [15, 16]. The

reasons for this are still unclear, but probably the effects of

acute inflammation differ from those of chronic inflammation.

In the present study we investigated the relationship of

adipokines and systemic inflammation in advanced-stage

NSCLC patients. Most studies have reported lower leptin

and adiponectin levels in cancer patients than in healthy

controls [17–19]. We also found lower serum adiponectin

levels in our NSCLC patients, whereas leptin levels were

similar in lung cancer cases and healthy volunteers.

We also examined the role of adipokines in cancer-asso-

ciated weight loss. Serum leptin concentration was decreased

in weight-losing cancer patients and had no correlation with

inflammatory markers. Our results do not support the

hypothesis that high serum leptin levels, produced by an

intense acute-phase reaction, were involved in anorexia and

cachexia associated with cancer. In response to weight loss,

adiponectin levels are expected to increase. Serum adipo-

nectin concentration of our weight-losing patients was

increased but the difference with that of the controls did not

reach statistical significance. Adipokines are regulated mainly

by changes in adipose tissue. Unlike starvation and other

cachectic states, cancer cachexia is often characterized by

preferential loss of skeletal mass rather than adipose tissue

[20]. Thus, the lack of association between adipokine levels

and weight loss may simply reflect the preservation of adipose

tissue. Another explanation may be their neutralization or

inhibition of secretion due to unknown interactions with other

proinflammatory cytokines. As a matter of fact, some studies

describe the inhibition of adiponectin production due to ele-

vated levels of other cytokines, including TNF-a [9, 21].

Similar to our results, lower serum leptin levels were

reported in cachectic lung cancer patients [19, 22, 23].

Published data suggested that leptin does not play an

important role in cancer cachexia development and chan-

ges of serum leptin concentration should rather be regarded

as a result of cachexia rather than being the cause of it

because its concentration depends on the total body fat

Table 3 Acute-phase reactants,

cytokine, and adipokines in

NSCLC patients with or without

weight loss

Values are mean ± SD

NSCLC non-small-cell lung

carcinoma, CRP C-reactive

protein, TNF-a tumor necrosis

factor a

NSCLC patients with

weight loss (n = 33)

NSCLC patients without

weight loss (n = 30)

P

Acute-phase reactants

CRP (mg/l) 48.60 ± 36.35 40.13 ± 35.89 0.242

Leucocyte (mkrL) 10136.36 ± 3611.6 9463.33 ± 2607.74 0.685

Thrombocyte (mkrL) 405515.15 ± 144739.66 328700.00 ± 111256.20 0.027

Ferritin (ng/ml) 280.69 ± 243.55 214.27 ± 158.05 0.379

Fibrinogen (mg/dl) 430.13 ± 136.43 443.65 ± 184.53 0.829

Albumin (g/dl) 4.25 ± 0.45 4.28 ± 0.54 0.060

Transferrin (lg/dl) 162.33 ± 53.02 197.13 ± 42.71 0.015

Cytokine and adipokines

TNF-a (pg/ml) 5.08 ± 1.27 5.95 ± 2.84 0.094

Leptin (pg/ml) 146.60 ± 84.36 217.73 ± 97.99 0.006

Adiponectin (ng/ml) 53.25 ± 28.56 50.00 ± 19.24 0.700

330 Lung (2012) 190:327–332

123

mass [18]. We also found a positive correlation between

leptin and BMI in NSCLC patients, as reported in previous

studies, which is compatible with normal functioning of the

afferent loop of the leptin feedback mechanism. In fact, a

decrease in leptin concentration should increase the appe-

tite and decrease energy utilization, resulting in increased

fat stores. However, this is not the case in cancer patients,

which may suggest a block in the hypothalamic response to

low circulating leptin concentrations.

Jamieson et al. [23] examined the relationship between

adiponectin and the systemic inflammatory response in

weight-losing patients with non-small-cell lung cancer.

Compared with the controls, the cancer group had a lower

BMI and circulating concentrations of albumin, free and total

leptin, and adiponectin. In contrast, the cancer group had

elevated circulating concentrations of IL-6 and CRP con-

centrations. However, weight loss, IL-6, or CRP concentra-

tions were not correlated with either adiponectin or free and

total leptin concentrations in the cancer group. They con-

cluded that adipokine production is normal and is unlikely to

play a major role in the abnormal fat metabolism in weight-

losing cancer patients. Likewise, in the present study, the

cancer group had lower BMI and circulating concentrations of

albumin and adiponectin. However, the systemic inflamma-

tory response, as evidenced by an increase in circulating

concentrations of acute-phase proteins (CRP, leucocyte, fer-

ritin, thrombocyte, and fibrinogen) was not accompanied by

an increase in leptin or adiponectin concentrations. Besides,

we could not find any correlation between adipokines and

markers of systemic inflammation, indicating the lack of

adipose tissue participation in generalized inflammation and

weight loss of NSCLC patients.

Conclusion

Our study revealed that leptin and adiponectin are neither

major contributors to weight loss nor related to cancer-

related systemic inflammatory response in patients with

advanced lung cancer. Whether leptin remains low in

weight-losing cancer patients as a compensatory mecha-

nism to preserve body fat content should be assessed in

further studies.

Acknowledgment The study was funded by the Adnan Menderes

University Research Foundation.

Conflict of interest None.

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