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Showing posts with label Eosinophilic esophagitis. Show all posts
Showing posts with label Eosinophilic esophagitis. Show all posts

Tuesday, 13 June 2017

Eosinophilic Esophagitis – another Granulocyte Disorder Associated with Autism  


There are many comorbidities associated with autism.  I have long held the view that these comorbidities hold the key to understanding each particular case of autism.  In many cases this may be far more useful than genetic testing, which only seems to help in a minority of cases.

“Ringed esophagus” aka “Corrugated esophagus”


This then allows you to put people into sub-groups that may well respond to the same therapy.  This may all sound like common sense, but apparently is not.

Eosinophilic esophagitis (EoE) is a relatively new diagnosis and it is applies to a certain type of reflux/GERD/GORD that might be associated with a difficulty in swallowing and may not respond well to the standard stomach acid lowering therapies.

It is likely that most people with Eosinophilic esophagitis have never been correctly diagnosed. Many people have taken several years to get the correct diagnosis.

It is known that Eosinophilic esophagitis is much more common in autism than the general population. One study showed that EoE is four time more likely to be diagnosed in someone with autism. I suspect many people with autism never have their GI problems fully diagnosed.

We now have to add some new science to this blog


Granulocytes

There is a great deal already in this blog about mast cells.  Many readers have children who have allergies, mast cell activation, or even mastocytosis.  Mast cells are the ones (but not the only ones) that release histamine.

Mast cells are just one type of a class of cells called Granulocytes, that are produced in your bone marrow.

Granulocytes are a category of white blood cells characterized by the presence of granules, which release their contents when they degranulate.

The four types of granulocytes are:- 


·        mast cells

These have been well covered in the past. These are what cause problems for people with pollen allergy.


·        eosinophils

Eosinophils play a crucial part in the killing of parasites because their granules contain a unique, toxic basic protein and cationic protein. Eosinophils regulate other immune cell functions (e.g., CD4+ T cells, dendritic cells, B cells, mast cells, neutrophils, and basophils), they are involved in the destruction of tumor cells, and they promote the repair of damaged tissue. Interleukin-5 interacts with eosinophils and causes them to grow and differentiate; IL-5 is produced by basophils.

Note that some people with autism find that the TSO helminth parasites modify their immune system and improve their autism. This may relate to what is contained in the granules of eosinophils.  


·        basophils 

Basophils are similar to mast cells, in that they contain prestored histamine within their granules. Unlike mast cells they circulate in your blood . Basophils are the least common of the granulocytes, representing about 0.5 to 1% of circulating white blood cells. However, they are the largest type of granulocyte. They are responsible for inflammatory reactions during immune response, as well as in the formation of acute and chronic allergic diseases, including anaphylaxis, asthma, atopic dermatitis and hay fever. They can produce histamine and serotonin that induce inflammation, and heparin that prevents blood clotting.

There is research underway to try to develop basophil stabilizers.


·        neutrophils

Neutrophils are normally found in the bloodstream. During the beginning phase of inflammation, particularly as a result of bacterial infection, environmental exposure, and some cancers, neutrophils are one of the first-responders of inflammatory cells to migrate towards the site of inflammation.

Neutrophils are recruited to the site of injury within minutes following trauma, and are the hallmark of acute inflammation; however, due to some pathogens being indigestible, they can be unable to resolve certain infections without the assistance of other types of immune cells.

Neutrophils also release an assortment of proteins in three types of granules by a process called degranulation. The contents of these granules have antimicrobial properties, and help combat infection.


An obvious question would be, if you know you have a problem with mast cells are you likely to have an issue with the other types of granulocytes?

One role of eosinophils is to regulate other immune cell functions (e.g., CD4+ T cells, dendritic cells, B cells, mast cells, neutrophils, and basophils).

The subject is highly complex and again not fully understood, but it is clear that granulocytes are all interrelated and so a problem with one may well be associated with a problem with others.

In the case of Eosinophilic esophagitis (EoE), both eosinophils and mast cell are directly involved.

Basophils, like mast cells, release histamine among other things when they degranulate.

Mast cells usually do not circulate in the blood stream, but instead are located in connective tissue.  Circulating granulocytes, like basophils can be recruited out of the blood into a tissue when needed.

So in addition to mast cell stabilizers perhaps, we might benefit from basophil and eosinophil stabilizers.

Surprisingly, the antihistamine cetirizine has Eosinophil-stabilizing properties, as does the asthma drug Montelukast. Both drugs are widely used in children.

Another substance, curine, also inhibits eosinophil influx and activation and is seen as a potential new treatment for asthma.  Interestingly the drug curine, is an alkaloid, that blocks L-type Ca²⁺ channels.

Regular readers may recall that I proposed the L-type calcium channel blocker Verapamil to control my son’s mast cell degranulation. Mast cells degranulate in a very complex fashion that involves the flow of Ca²⁺.

This may or may not be a coincidence. 

Fullerene nanomaterials are being developed as both mast cell and peripheral blood basophil stabilizers.



L-type calcium channels and GI disorders in Autism

There are many types of GI disorder in autism, however I suggest that a large group can be categorized as being broadly Granulocyte Disorders, which may well all respond to L-type calcium channel blockers, to some extent.

Indeed this may be a better solution than the widely used cromolyn sodium.

Perhaps people with autism, and their family members have certain calcium channels that are either overexpressed, or do not close fast enough, leading to a higher level of intracellular calcium.  This of course ties back in with Professor Gargus and his theories about IP3R and the calcium store inside the endoplasmic reticulum”.

This all gets extremely complex.

My rather simple suggestion would be that if you have autism and any GI problem from the esophagus downwards, a three day trial of verapamil just might change your life.  As is almost always the case, there are some people who do not tolerate verapamil.



Interleukin 5

Interleukin 5 (IL-5) is an inflammatory cytokine produced by type-2 T helper cells  (Th2), mast cells, basophils and eosinophils.

IL-5 interacts with eosinophils and causes them to grow and differentiate.

IL-5 has long been associated with the cause of several allergic diseases including allergic rhinitis and asthma, where a large increase in the number of circulating, airway tissue, and induced sputum eosinophils have been observed.

You might expect high levels of IL-5 in people with Eosinophilic esophagitis (EoE)



Anti–IL-5 therapy is associated with marked decreases in peripheral blood and esophageal eosinophilia (including the number of CCR3+ blood cells) in patients with EE and improved clinical outcomes.


Not surprisingly the same anti-IL-5 therapy has been approved to treat severe asthma.


Patients are given mepolizumab by injection every four weeks. It costs £840 per dose.



Mepolizumab for autism?

It is very expensive, so I doubt many people will think of Mepolizumab for autism.  If you have EoE, or severe asthma, you may be able to access this IL-5 therapy, my guess is that it would also reduce the severity of any comorbid autism.


Back to Eosinophilic Esophagitis

I was writing a while ago about food allergy in my book and came across the opinion that food allergy is no more common in autism than in typical people, but what is more common is Eosinophilic Esophagitis.

Eosinophilic esophagitis is a chronic immune system disease. It has been identified only in the past two decades, but is now considered a major cause of digestive system (gastrointestinal) illness.  In many cases it likely remains undiagnosed. If it continues, after a few years swallowing becomes difficult, in part because a “ringed esophagus” develops that impedes the passage of food.

As seems to be often the case there are plenty of contradictions in the diagnosis and treatment, as you will find as you read on.

The symptoms are broadly what would normally be diagnosed as reflux/GERD/GORD. This is very often found in people with autism and I expect in their relatives.

It is relevant to autism because it will be yet another comorbidity that when treated should improve autism, but it is also another marker of a particular sub-group of autism.

There are numerous other GI conditions comorbid with autism - colitis, IBD, IBS etc.  In the end I imagine that the molecular basis of some of these diagnoses is actually the same, so you will find the same therapies may be effective.

It looks like that one common factor is the mast cell and, just as in pollen allergy and asthma, stabilizing mast cells yields great benefit. Stabilizing mast cells is complex but involves the flow of calcium ions, Ca2+.  By modifying the flow of Ca2+ you can prevent mast cells degranulating.  This was one of my earlier discoveries, but there is now research showing the L type calcium channels “open” mast cells.  Keeping these channels closed is actually quite simple.

It would seem logical that the same approach could be therapeutic to other conditions that are, at least in part, mediated by mast cells.

According to the Mayo Clinic these are symptoms of eosinophilic-esophagitis


Adults:

·         Difficulty swallowing (dysphagia)

·         Food impaction

·         Chest pain that is often centrally located and does not respond to antacids

·         Persistent heartburn

·         Upper abdominal pain

·         No response to gastroesophageal reflux disease (GERD) medication

·         Backflow of undigested food (regurgitation)


Children:

·         Difficulty feeding

·         Vomiting

·         Abdominal pain

·         Difficulty swallowing (dysphagia)

·         Food impaction

·         No response to GERD medication

·         Failure to thrive (poor growth, malnutrition and weight loss)


The diagnosis of EoE is typically made on the combination of symptoms and findings of diagnostic testing.


Prior to the development of the EE Diagnostic Panel, EoE could only be diagnosed if gastroesophageal reflux did not respond to a six-week trial of twice-a-day high-dose proton-pump inhibitors (PPIs) or if a negative ambulatory pH study ruled out gastroesophageal reflux disease (GERD).

Treatment strategies include dietary modification to exclude food allergens, medical therapy, and mechanical dilatation of the esophagus.

The current recommendation for first line treatment is PPI in lieu of diet as a significant portion of EOE cases respond to this, and it is a low risk, low cost treatment.

The second and third line therapies are an elimination diet of either the 6 or 4 most common triggers, or topical corticosteroids, including both fluticasone, and topical viscous budesonide.

Elimination diets would be followed by re-introduction of foods under supervision if the first diet is successful. Allergy evaluation has not been found to be an effective means to determine what foods to eliminate.

  


MAST CELL STABILIZERS

In a small case series, Cromolyn sodium failed to show any clinical or histologic improvement in EoE patients

LEUKOTRIENE INHIBITORS

Montelukast is an eosinophil stabilizing agent. It improved clinical symptoms in EoE but there was no histological improvement

PROGNOSIS

As mentioned earlier, EoE is a chronic inflammatory disease of the esophagus. The inflammation leads to remodeling, fibrosis and stricture. Fortunately, no case of esophageal malignancy has been reported in EoE. Patients are generally diagnosed after several years of their symptoms. Although symptomatic improvement occurs after treatment, recurrence is common after discontinuation of treatment. So maintenance therapy is needed to prevent recurrences. At the present time there is no head to head study to suggest the best maintenance treatment. Continuation of swallowed corticosteroid and/or dietary therapy should be done in all EoE patients particularly in those with history of food impaction, dysphagia, esophageal stricture, and in those with rapid symptomatic and histologic relapse following initial treatment



Eosinophilic esophagitis and Mast Cells

Eosinophilic esophagitis is called Eosinophilic because it is mediated by Eosinophils, however it has been established that mast cells also play a role. 



Whereas prior studies have primarily focused on the role of eosinophils in disease diagnosis and pathogenesis, this study investigates the involvement of mast cells.

Herein we have identified local mastocytosis and mast cell degranulation in the esophagus of EE patients; identified an esophageal mast cell associated transcriptome that is significantly divergent from the eosinophil-associated transcriptome with CPA3 mRNA levels serving as the best mast cell surrogate marker; and provide evidence for the involvement of KIT ligand in the pathogenesis of EE.


One possible explanation for eosinophilic esophagitis:















A potential immunological mechanism involved in the pathogenesis of EoE. An uncontrolled TH2 immune response initiated by an allergic insult results in the transition of the esophagus from a normal (NL) to EoE phenotype through enhanced IL-13 production that induces highly elevated CCL26 (eotaxin-3) expression by esophageal epithelium. Dysregulated TH2 immune response and enhanced CCL26 secretion together promote the infiltration of CD4+TH2 cells, eosinophils, and mast cells, and potentially, type-2 innate lymphoid cells (ILC2) and CD4+TH9 cells; into the esophagus. TGF-β and IL-4 produced by the activated mast cells and CD4+TH2 cells may induce eosinophils, ILC2, and/or CD4+TH9 cells to produce IL-9, which in turn, promotes esophageal mastocytosis that contributes to the development of EoE pathophysiology.



Possible Eosinophil stabilizers


CONCLUSIONS Eosinophil-stabilizing properties and favorable safety profile make cetirizine an attractive add-on therapy for NMO. Thus far it has been well-tolerated in our patient population, with incoming data about efficacy expected over the coming months




·        Curine is a bisbenzylisoquinoline alkaloid from Chondrodendron platyphyllum.

·        Curine inhibits eosinophil influx and activation and airway hyper-responsiveness.

·        Curine mechanisms involve inhibition of Ca2+ influx, and IL-13 and eotaxin secretion.

·        No significant toxicity was observed in mice orally treated with curine for 7 days.

·         Curine has the potential for the development of anti-asthmatic drugs.

  

Conclusion

Non conventional therapies for eosinophilic esophagitis might include:-


·        Cetirizine

·        Verapamil

·        Montelukast

·        Curine

The very expensive therapy is Mepolizumab.

If you have one type granulocyte causing a disorder, is seems almost inevitable that the other types of granulocyte are also involved.

Treating granulocyte disorders should improve autism and left untreated they may mask the effect of otherwise useful autism therapies. 

One reader did previously suggest a bone marrow transplant for autism. A rather radical solution, but if someone with autism was given donor bone marrow as part of another therapy, you might well see their autism improve.