The Inflammatory Process and Autism- Implications for Treatment?

Peter Della Bella, MDClinical Assistant Professor of Child and Adolescent PsychiatryNYU School of Medicine

October 6, 2013 17th Annual Advances in Autism ConferenceIcahn School of Medicine at Mount SinaiSeaver Autism Center for Research and Treatment

Our Protection from Pathogens

Barrier strategies• Skin, mucus, tears, coughing, sneezing, cell walls, “good” intestinal flora

Ready-to-Go strategies (Innate Immunity) • INFLAMMATION

– CIRCULATING PROTEINS (*COMPLEMENT and CYTOKINES) to *coat invaders & present them for destruction, and **signalling/amplification of the response)

– LEUKOCYTES/MACROPHAGES/…

Learned strategies (Adaptive Immunity)• use B- and T-lymphocytes, result in immune memory (e.g. antibodies)

Inflammation

• As part of innate immunity, damaged cells leak chemical factors into the surrounding tissue and blood: these widen the blood vessel, make it more permeable, and recruit white blood cells to the site to “fight” the problem

• “rubor, calor, tumor, dolor”

Inflammation is a form of protection that results from the immune process.

- Trauma, burns, radiation, chemicals, incl alcohol- Infection with bacteria, viruses- Auto-immunity- Obesity – fat cells release cytokines- Stress

Inflammation can be acute or chronic (eg Crohn’s disease, rheumatoid arthritis, asthma).

Leukocytes release destructive chemicals (ROS) to kill the invaders and do away with dying cells, but also damage healthy cells and DNA, even more so when chronic.

Chronic inflammation is now known to play a role in many disease states (heart disease, cancer, depression). And possibly autism.

Cytokines

• Small proteins (peptides) which signal immune cells and amplify the host response

• Increase up to 1000 fold during infection and activate other cytokines

• Causes sickness behavior (curled up, quiet, self-protective, conservation)

• Eg interferons, interleukins• (Cytokine storms as an overreaction)

Some Proteins are involved both in Immune Process and the Neurological Development!

• Cytokines regulate the production of cell surface molecules in both immune cells and the brain during embryogenesis. Helping with Immunologic memory and neurological memory.– Problems with MHC function can result in immune dysfunction and the

miswiring of brain synapses

• Complement is used by the immune system to punch holes in cell membranes and kill bacteria, but also by the brain to prune synapses– Improper activation can result in improper destruction of cell

connections (eg memory and cognitive loss in depression and PTSD)

In people with autism, a number of studies have also shown that inflammatory cytokines (tumor necrosis factor, interferon, interleukins) are elevated in blood and cerebrospinal fluid.

J Neuroinflammation. 2012; 9: 265.

Study at Johns Hopkins

• Regressive type of autism is associated with increased inflammatory cytokines and inflammatory processes in neuroglial and astroglial in several brain regions

• Glial cells (non-neurons, the most common brain cell)– Direct neuronal migration in embryos– Scaffolding– Part of the blood brain barrier– Transport glutamate, GABA

Vargas, Zimmerman, et al:• Ann neuro 2005 Feb; 57(2); 304 • Inter rev psychiatry 2005 Dec; 17(6), 485-95

An integrative model…

Inflammatory processes in mother and fetus -> leads to more cytokine and complement -> miswiring, neurotransmitter effects, more porous blood brain barrier, an enhanced “aging” process in the brain -> altered development

These processes may be provoked in a variety ways, or may be over-provoked in those with genetic predisposition.

Frontiers in Neurosci. 2013; 7: 123.

Does maternal inflammation lead to fetal inflammation?

“In 2010, Atladottir et al. reported an association between maternal bacterial infection during the second trimester and the diagnosis of ASD in the child… They suggested that the observed association could be due to (transplacental passage of maternally produced cytokines or antibodies in response to the infection). ”

Front Neurosci. 2013; 7: 123.Arch. Pediatr. Adolesc. Med. 164, 470–477.

But if the model focuses on altered fetal development, isn’t

it too late to treat later on?

Treatment Implications?

• Minocycline• Steroids and common anti-inflammatories?• Hygiene Hypothesis• Flavonoids

Do NOT try this at home!

• The researchers at Hopkins made it clear: Associations don’t = causation• Inflammation can be a cause, or it can be a result• Altering the inflammatory process can cause a lot worse problems• Johns Hopkins FAQs:

THERE IS CURRENTLY NO indication for using anti-inflammatory medications in patients with autism- steroids (e.g. prednisone or methylprednisolone), - immunosupressants (e.g. Azathioprine, methotrexate, cyclophosphamide)- intravenous immunoglobulins, IVIGs

THESE WORK ON ADAPTIVE IMMUNITY (effector T cells, immunoglobulin production)

THEY WOULD NOT SIGNIFICANTLY EFFECT INNATE IMMUNITY (neuroglial activation)

THERE ARE STUDIES in this area (aspirin, pioglitzone ACTOS), but have a long way to go.

Minocycline

• Minocycline is an antibiotic which crosses the blood-brain barrier and limits neuroinflammation and glial activation

• Used in Fragile X, Huntingdon’s Disease to stabilize and protect neurons• Reduces inflammatory response and cell death after stroke, seizures, and

with amyloid plaques in Alzheimers• Recent open-label n=10 study at Johns Hopkins and the NIMH with

1.4mg/kg dose showed no significant clinical or behavioral effects !

J Neurodev Disord. 2013; 5(1): 9

The Hygiene Hypothesis• Central now to theories about the rise of allergenic and autoimmune

diseases (asthma, hayfever, eczema, IBD, autism?) • Lack of exposure to infectious stimuli both internally (intestinal flora) and

externally (parasites) lead to an underdeveloped adaptive immune system (particularly suppressor T cells, which shut down the immune system after the invader is gone)

• Immunologic abnormalities and family history of auto-immune disorders. • Trichuris suis ova (TSO) – porcine whipworm eggs - extensively studied in

Crohn’s, UC, MS, asthma. Benefits for autism?

• Hygiene hypothesis support (Prugnolle et al., 2005): populations with high pathogen diversity (eg less developed countries) have increased HLA diversity relative to their average genomic diversity

Flavonoids

• Plant pigments . Group: polyphenols, renowned antioxidants.• Renowned anti-oxidants and anti-inflammatory agents, inhibiting the release of

inflammatory mediators from human mast cells, and reduce maternal interleukin 6-induced autism-like features in mice. A case series of parental reports on 37 children with ASD who took a supplement containing luteolin and quercetin reported gains in eye contact, attention and social interaction according to parental reports.

• A new open-label, prospective study completed in May ‘13 in Greece, looked at 50 children age 4-10 with ASD given flavonoids. Measures: global effects (CGI), behavioral problems (ABC), functioning (Vineland). No results yet. (clinicaltrials.gov)

Resource: (USDA) Sources of Flavonoids in the US Diet…

Blueberries, black tea, dark chocolate, parsley, wine

So, no great evidence for treatment effects at this time.

Maybe we should be focusing on maternal-fetal inflammation

and then prevention?