Could a silent virus trigger celiac disease? Scientists say...maybe...

The gluten-free lifestyle has moved from relative obscurity to mainstream use.  For most individuals, a gluten-free diet will be a passing obsession (although one which may result in increased attention to what is in food - which is a very good result) but for those with celiac disease it is a welcome societal movement.  Celiac disease is an autoimmune condition which presents with gastrointestinal distress (pain, bloating, cramping), steatorrhea/diarrhea and malabsorption.  Sounds a bit like IBS, right?  Many of the clinical symptoms of celiac disease and IBS are identical, making a true celiac disease diagnosis challenging for both patient and practitioner.  A person with true celiac disease has a specific and measurable autoimmune response to the ingestion of dietary gluten.  IBS symptoms are often non-specific (i.e. varying severity, length, location, etc.) and worsen with a virety of triggers (gluten may be a trigger for IBS symptoms, but other dietary (lactose, soy, fructose) and lifestyle factors (chronic stress) influence this condition).  Fortunately, diagnostic tests for celiac disease are becoming more common and often begin with a simple blood analysis - unfortunately, however, IBS has not lent itself to reliable diagnostic measures.  Several specific criteria are used to confirm a diagnosis of celiac disease, although every body and everybody is different: 

1) HLA-DQA1 or HLA-DQB1 gene variants (this is very important - if you do not have the 'celiac gene mutation' you do not have celiac disease; non-celiac gluten sensitivity is a related condition which does not invoke a true autoimmune response but has been described as a gluten-related inflammatory response)
2) Elevated antibody levels (tTG, IgA, IgG - these are the 'gluten antibodies' which can be quantified in the blood and used as a diagnostic marker for the autoimmune condition)
4) Vitamin A, D, E and K deficiencies (fat-soluble vitamins are less readily absorbed due to intestinal damage)
5) Damaged (atrophied) intestinal lining confirmed by small bowel biopsy
6) Environmental trigger resulting in decetable immune response

Common factors 1-5 are easily tested for and confirmed by a gastrointestinal specialist - most of them are quantifiable and/or visually informative.  The 'environmental trigger' aspect of celiac disease (6 listed above) has remained the most elusive requirement for disease onset.  How do we even know that an environmental trigger is important?   Scientists agree that environmental risk factors are likely to be a cause of consideration based (so far...) purely on statistics.  Celiac disease occurs globally in 1 out of 100 people.  However, only 3-4% of individuals who carry the HLA-DQA1 or HLA-DQB1 gene variants ever develop celiac disease - what happens or does not happen to the other 96-97% who never progress?  These values are reported in a recent study published in Science which reports the first experimental observation of celiac disease onset after exposure to a known environmental trigger.  Their study, titled 'Reovirus infection triggers inflammatory responses to dietary antigens and development of celiac disease' describes a controlled experiment in which genetically susceptible mice, living on a gluten-containing diet but showing no clinically diagnostic celiac disease symptoms, are exposed to a known reovirus.  Onset of celiac disease after viral exposure was confirmed by a measurable increase in immune response pathways, specifically those which promote the production of T-cells (immune cells) which specifically respond to the gluten antigen.  This particular immune response pathway is triggered by HLA-DQ2 and HLA-DQ8 molecules, which are coded for by the HLA-DQA1 or HLA-DQB1 gene variants.  

So, the mice had these genes and consumed a gluten-containing diet but did not show signs of celiac disease prior to viral exposure.  What this study shows is that the externally applied environmental factor (the reovirus - which is avirulent and causes no 'viral symptoms') has 'turned on' the mutated gene (just like a ligh switch).  When the gene variant is 'turned off,' it is still there but it is not physiologically active, whereas when the gene is 'turned on' downstream physiological changes have been shown induce disease progression.  Now, would the mice have eventually developed celiac disease if they had not been exposed to the reovirus?  Maybe.  Would they have developed celiac disease from some other environmental trigger?  Maybe.  What this study provides is only one piece of the enormous jigsaw puzzle describing celiac disease - and most of the pieces are still scrambled in the box!  There are likely thousands of additional environmental triggers which influence disease progression, and not every genetically susceptible individual who encounters a reovirus will go on to develop celiac disease.  However, direct demonstration and observation of environmentally triggered change in gene expression promoting the development of celiac disease is a HUGE step towards understanding the complicated relationship between food and the immune system.  I'll raise a glass of (gluten-free) beer to that!

Spotlight on Anthera and AzurRx for next-generation PERT

The impact of FDA-approved pancreatic enzyme replacements cannot be overstated.  In fact, the World Health Organization (WHO) includes pancreatic enzymes on the 'Model List of Essential Medicines' for both adults and children.  These 'living' lists are assessed and updated every two years to identify the 'minimum medicine needs for a basic health care system, listing the most efficacious, safe and cost effective medicines for priority conditions.'  For many, especially those with cystic fibrosis or living without a pancreas, replacement enzymes are lifesaving and life-sustaining.

Research into next-generation replacement enzymes seeks to improve upon current challenges for those who use PERTs in whatever capacity - from supportive care, such as in mild to moderate pancreatic insufficiency, to life-long dependency.  Amongst the concerns of those either making (R&D sector) or taking (patients) replacement enzymes are:

• Dosing consistency/individualized dosing - there is no one size fits all method for prescribing enzymes (especially when there are three types of enzyme in each pill!), most individuals on pancreatic enzymes benefit most from the lipase
• Enzyme source - due to personal or religious reasons, enzymes derived from pigs is not an available dietary addition
• Side effects - bloating, gas, stomach pain, diarrhea, constipation and nausea are all listed as side effects for replacement enzymes at normal dosing regimes; although rare, long-standing enzyme overdose can lead to a condition called fibrosing colonopathy
• Additional required medication - it is very common to co-prescribe a proton pump inhibitor alongside replacement enzymes to regulate gastric pH (and these come with their own list of side effects!)

Two up-and-coming biotech companies are slowly gaining attention in the PERT community and market.  Their research is addressing several of the challenges listed above and is made possible by the smallest of creatures - bacteria and yeast!

Anthera Pharmaceuticals is a small biotech company in California focusing on a next-generation  pancreatic enzyme replacement therapy which aims to reduce patient pill burden.  The most common ways for PERTs to fail is patient non-compliance, fundamentally forgetting to take enzymes prior to every meal and snack.  This often means taking up to 6 pills 4-5 times per day, every day, to ensure therapeutic benefit.  One way to reduce the quantity of daily pills is to improve the quality of the enzymes in each pill.  The proprietary enzyme blend in Anthera's Sollpura drug candidate is biologically engineered (this means made from a biological organism such as a bacteria - no pigs involved!) and features crystalline and cross-linked enzymes.  Crystallization and cross-linking bring stability to the enzyme molecules, ensuring that low gastric pH and the presence/absence of bile salts do no effect their availability.  In addition, Sollpura has been formulated into both a tablet and sachet (water-soluble!) form, the later being particularly attractive for pediatric cystic fibrosis patients with pancreatic insufficiency.   The Sollpura formulations are currently in two clinical trials.   

AzurRx BioPharma is a publically traded biopharmaceutical company working in the areas of gastrointestinal and microbiome-related disorders and diseases.  Their drug candidate, MS1819 lipase is currently in phase IIa clinical trials (to profile the safety and efficacy in comparison with currently available PERTs).  As the name suggests, this produce is either a lipase-only enzyme capsule or one which features a significant percentage of lipase with respect to amylase and protease.  As described on their website, although amylases and proteases are produced alongside lipases in the pancreas, only supplementation of the lipase is thought to be necessary for treatment of EPI.  In fact, proteases in currently approved PERTs have been implicated in the cause of fibrosing colonopathy, a rare but very serious side effect of taking replacement enzymes.  Looking to the microscopic world for answers, MS1819 lipase has also been biologically engineered - but this time from yeast rather than bacteria!  Yes, the same microorganisms which serve us by fermenting wheat to make bread, grapes to make wine and hops to make beer have been engineered to produce highly potent and stable lipases for treating EPI.    

Anthera and AzurRx are just two of a growing number of biopharmaceutical companies approaching pancreatic enzyme improvements using non-traditional (biological) methods.  The use of microorganisms such as bacteria, yeast and algae for the production of valuable materials including antibiotics (many of which are also on the WHO's Model List of Essential Medicines), food and even crude oil demonstrates the viability and influence of biologically-derived products.  A biological approach to enzyme production may provide not only a renewable and reliable method for enzyme production (with the potential to tailor enzymes on an individual basis) but may help alleviate the burden we place on animal-derived healthcare products.