Bone involvement in ISM, SSM, SM-AHNMD and ASM: More literature review (part 3)

A 2009 paper looked at prognosis of 157 ISM patients (Escribano 2009). 27% had bone involvement, with 18% patients having osteoporosis, 6% having diffuse bone sclerosis, 4% having patchy bone sclerosis 2% having small osteolysis and 3% having pathological fracture.

A 2012 paper (van der Veer 2012) assessed the frequency of osteoporosis and osteoporotic fractures in a group of 157 ISM patients. They found 28% had osteoporosis, with 27% having osteoporosis of the lumbar spine and 1% having osteoporosis of the hip. 4% had evidence of osteosclerosis.

43% of patients under 50 years old had had at least one fracture (osteoporotic or not) and 61% of patients over 50 years old had had at least one fracture. 27% of patients had one or more vertebral fractures and 21% had non-vertebral, osteoporotic fractures. 23% of male patients under 50 had osteoporosis as well as 38% over 50. 12% of women under 50 had osteoporosis as well as 33% over 50. In total, 37% had osteoporotic fractures. In the group with comorbidities that might cause osteoporosis or fractures, 49% had osteoporotic fractures and 37% had osteoporosis. 59% ISM patients without UP had osteoporotic fractures compared to 28% with UP.

A 2013 paper (Matito 2013) looked at the association of baseline serum tryptase with disease features, including progression to SSM or ASM. 74 patients with ISM were included in the study and were followed for at least 48 months. None of them received cytoreductive therapy. Patients with an increased serum baseline tryptase slope and those without significant tryptase increase had similar prevalence of osteoporosis, patchy bone sclerosis and diffuse bone sclerosis at both presentation and end of study. However, the group with increased serum baseline tryptase was more likely to develop diffuse bone sclerosis in the time span between the beginning of the study and the end of the study (13% vs 2% without significant tryptase increase).

Among the group with low serum baseline tryptase increase, 9% had osteoporosis at the start, and 14% at the end; 5% had patchy osteosclerosis at the end; 2% had diffuse bone sclerosis at the end. None in this group progressed to SSM or ASM.

Among the group with high serum baseline tryptase increase, 10% had osteoporosis at the start, and 16% at the end; 6% had patchy osteosclerosis at the end; 13% had diffuse bone sclerosis at the end. 13% progressed to SSM and 6% to ASM.

Four patients in this study progressed to SSM after the start of the study, in a time ranging from 8-85 months. All had serum baseline tryptase of at least 200 ng/ml and had increased serum baseline tryptase slope. They also had D816V CKIT mutation in cells other than mast cells. Two of these patients progressed to ASM. Both of these patients had diffuse bone sclerosis and swelling of both the liver and spleen. The authors of this paper recommend special attention to the development of hepatomegaly and splenomegaly and diffuse bone sclerosis.

 

References:

Maurizio Rossini, et al. Bone mineral density, bone turnover markers and fractures in patients with indolent systemic mastocytosis. Bone 49 (2011) 880–885.

Theoharides TC, Boucher W, Spear K. Serum interleukin-6 reflects disease severity and osteoporosis in mastocytosis patients. Int Arch Allergy Immunol 2002;128: 344–50.

Dobigny C, Saffar JL. H1 and H2 histamine receptors modulate osteoclastic resorption by different pathways: evidence obtained by using receptor antagonists in a rat synchronized resorption model. J Cell Physiol. 1997 Oct;173(1):10-8.

Barete S, Assous N, de Gennes C, Granpeix C, Feger F, Palmerini F, et al. Systemic mastocytosis and bone involvement in a cohort of 75 patients. Ann Rheum Dis 2010;69:1838–41.

Nicolas Guillaume, et al. Bone Complications of Mastocytosis: A Link between Clinical and Biological Characteristics. The American Journal of Medicine (2013) 126, 75.e1-75.e7

van der Veer, W. van der Goot, J. G. R. de Monchy, H. C. Kluin-Nelemans & J. J. van Doormaal. High prevalence of fractures and osteoporosis in patients with indolent systemic mastocytosis. Allergy 67 (2012) 431–438.

Kushnir-Sukhov NM, Brittain E, Reynolds JC, Akin C, Metcalfe DD. Elevated tryptase levels are associated with greater bone density in a cohort of patients with mastocytosis. Int Arch Allergy Immunol. 2006;139(3):265-70. Epub 2006 Jan 30.

Matito A, Morgado JM, Álvarez-Twose I, Laura Sánchez-Muñoz, Pedreira CE, et al. (2013) Serum Tryptase Monitoring in Indolent Systemic Mastocytosis: Association with Disease Features and Patient Outcome. PLoS ONE 8(10): e76116. doi:10.1371/journal.pone.0076116

Escribano L, A lvarez-Twose I, Sanchez-Munoz L, Garcia-Montero A, Nunez R, Almeida J et al. Prognosis in adult indolent systemic mastocytosis: a long-term study of the Spanish network on mastocytosis in a series of 145 patients. J Allergy Clin Immunol 2009;124:514–521.

Heritable mutations in mastocytosis

While the most well-known mutation associated with SM is the CKIT D816V, there are numerous other mutations that can contribute to mast cell disease and presentation. The CKIT gene produces a tyrosine kinase receptor on the outside of the mast cell. Tyrosine kinases function as switches that turn certain cell functions on and off. When stem cell factor binds to the CKIT receptor, it turns on the signal for the mast cell to live longer than usual and to make more mast cells.

The D816V mutation is located in a specific part of the CKIT gene called exon 17. As many as 44% of SM patients have CKIT mutations outside of exon 17, either alone or in addition to the D816V mutation. (Please note that for the purposes of this post, SM is used to refer to SM, ASM and SM-AHNMD in keeping with the source literature.) Still, most doctors and researchers believe the D816V mutation is not heritable. This has important implications because it means many doctors also believe mast cell disease is sporadic and not heritable.

Almost 75% of MCAD (SM, MCAS, MCL) patients had at least one first degree relative with MCAD. This study, published in 2013, demonstrated that despite the non-heritable nature of the D816V mutation, mast cell disease is indeed heritable. Currently, four heritable mutations present in mast cell patients have been identified.

CKIT is often called KIT. In one family in which the mother, daughter and granddaughter have all have indolent SM, they were all found to have a deletion at position 409 in KIT (called KITdel409.) The KIT F522C mutation has been associated with ISM.   Another heritable mutation, KIT K509I, has been identified multiple times by different researchers. The first publication to identify this mutation was published in 2006. It has been found in a mother/daughter set who have ISM, and in another mother/daughter set in which the mother has ASM and the daughter has CM. This mutation was noted in a 2014 paper to be associated with well differentiated SM.

There have been reports of families in which multiple members with ISM or SM-AHNMD had the D816V mutation. Importantly, in these patients, the mutation was readily found in numerous cell types, including mast cells, CD34+ hematopoietic precursor cells, blood leukocytes, oral epithelial cells, blast cells and erythroid precursors. Despite this finding, the majority of literature continues to report the D816V mutation as not heritable.

 

References:

G.J. Molderings. The genetic basis of mast cell activation disease – looking through a glass darkly. Critical Reviews in Oncology/Hematology 2014.

G.J. Molderings, B. Haenisch, M. Bogdanow, R. Fimmers, M.M. Nöthen. Familial occurrence of systemic mast cell activation disease. PLoS One, 8 (2013), p. e76241

Hartmann, E. Wardelmann, Y. Ma, S. Merkelbach-Bruse, L.M. Preussenr, C. Woolery, et al. Novel germline mutation of KIT associated with familial gastrointestinal stromal tumors and mastocytosis. Gastroenterology, 129 (2005), pp. 1042–1046

R.A. Speight, A. Nicolle, S.J. Needham, M.W. Verrill, J. Bryon, S. Panter. Rare germline mutation of KIT with imatinib-resistant multiple GI stromal tumors and mastocytosis. J Clin Oncol, 31 (2013), pp. e245–e247

de Melo Campos, J.A. Machado-Neto, A.S.S. Duarte, R. Scopim-Ribeiro, F.F. de Carvalho Barra, J.Vassallo, et al.Familial mastocytosis: identification of KIT K509I mutation and its in vitro sensitivity to imatinib, dasatinib and PK412. Blood, 122 (2013), p. 5267

L.Y. Zhang, M.L. Smith, B. Schultheis, J. Fitzgibbon, T.A. Lister, J.V. Melo, et al. A novel K5091 mutation of KIT identified in familial mastocytosis – in vitro and in vivo responsiveness to imatinib therapy. Leukemia Res, 30 (2006), pp. 373–378

E.C. Chan, Y. Bai, A.S. Kirshenbaum, E.R. Fischer, O. Simakova, G. Bandara, et al. Mastocytosis associated with a rare germline KIT K509I mutation displays a well-differentiated mast cell phenotype. J Allergy Clin Immunol, 134 (2014), pp. 178–187

Akin, G. Fumo, A.S. Yavuz, P.E. Lipsky, L. Neckers, D.D. Metcalfe. A novel form of mastocytosis associated with a transmembrane c- Kit mutation and response to imatinib. Blood, 103 (2004), pp. 3222–3225

Escribano, R. Nunez-Lopez, M. Jara, A. Garcia-Montero, A. Prados, C. Teodosio, et al. Indolent systemic mastocytosis with germline D816 V somatic c-kit mutation evolving to an acute myeloid leukemia. J Allery Clin Immunol, 117 (Suppl.) (2006), p. S125

Food allergy series: Mast cell food reactions and the low histamine diet

When I started my posts on food allergies, I listed out the causes of food hypersensitivity. Notably absent from this list was mast cell disease. Even among detailed publications on mast cell disease, food reactions are often unmentioned (though potentially subsequent anaphylaxis is usually included.) Unfortunately, food reactions in mast cell disease are still not well understood. Even among experts, the nature and importance of food reactions in overall disease is the subject of much disagreement. Some contend that food reactions are a manifestation of general mast cell reactivity, while some think the foods specifically are sources of reactions. Following this logic, some experts believe in the validity of observing a low histamine diet while others do not.

So please keep in mind that the science behind the low histamine diet is not well accepted or even well defined. I’m going to give you my general comments on the low histamine diet, how I eat and how it has worked for me. It is my personal opinion.

A low histamine diet is one which eliminates or minimizes histamine in the food consumed. I have talked at great length about histamine so I’m not going to reiterate that here. What I will say is that exogenous histamine has been shown to induce mast cell degranulation, which means that histamine from an outside source can cause degranulation. It makes sense to me as a scientist that eating histamine rich foods will cause mast cell degranulation. It especially makes sense because the most commonly problematic food substances for mast cell patients, like alcohol, vinegar and aged cheeses, are major degranulators. I have never been able to tolerate alcohol, so it made sense to me that it was because of degranulation. Again, I prefer to lean on good studies, but in the absence of that, I will accept my own experience living in this body.

Last winter, I was in a lot of pain and generally having a sucky time of life. One of the changes I discussed with my doctors was the low histamine diet. It was in the “this can’t hurt” category. I had put off elimination dieting for a long time due to time and financial constraints, but it seemed like the appropriate time to do it had arrived.

One of the first things that became aware to me was that there is no universally agreed upon low histamine diet. There are lots of websites that discuss it and lay out diet guidelines and none of them are in complete agreement. So I just picked the one that seemed the most reasonable to me and went from there. As a mast cell patient, any diet you pick will require customization.

The diet I picked was the Histamine and Tyramine Restricted Diet by Janice Joneja. It can be found on the Mastocytosis Society Canada page.   I like this diet a lot. I do not know Dr. Joneja personally, but when I read diet/nutrition articles by her, I find them to be based in science. They meet my common sense rule. I’m going to summarize the general guidelines of the diet below along with my comments.

Key guidelines for a low histamine diet:

  • Anything fermented should be avoided. Fermentation produces histamine as a side product. Some are only sensitive to yeast fermented products while some find that fermentation from any organism is triggering.
  • No preservatives and no dyes.
  • No leftovers and nothing overly ripe. This is one of the harder parts of this diet, but I find it very important. Fresh or frozen products seem okay. I have mixed success with thawing frozen meat, but lots of people do it successfully. The key is to not cook something, put it in the fridge and eat it three days later.
  • No canned products.
  • No pickled products.

Milk and milk products: Avoid fermented products, like cheeses of all kinds, kefir, yogurt, sour cream, cottage cheese and cream cheese. A fair amount of milk products are allowed. Milk (cow, goat, coconut) is allowed, as are cheese type products that are made without fermentation (mascarpone, ricotta, panir.) Some versions of this diet allow mozzarella cheese and I find that it is safe for me. Ice cream is allowed if it doesn’t contain other disallowed ingredients. Cream products are okay, too.

Grains, breads: Yeast is the component most likely to be triggering in these products. Many people choose to restrict gluten due to their individual biologic reactions to it. Gluten is not specifically restricted on this diet, but I can tell you that it basically ends up being excluded anyway because gluten containing products usually also contain yeast. Pure, unbleached flour or grain of any kind is allowed. Products that use baking powder for leavening are allowed, like biscuits, soda bread, scones and muffins. Crackers without yeast are allowed, as are cereals if they don’t contain excluded ingredients, including artificial dyes or preservatives. I have a very difficult time finding low histamine baked products that are premade, so I generally make my own. It is surprisingly easy to make good tasting baked products with safe ingredients at home.

Vegetables: The list of vegetables that aren’t allowed feels really disjointed and counterintuitive. There is not much to do beyond committing it to memory. Not allowed: potato, avocado, green beans, eggplant, pumpkin, sauerkraut, spinach, sweet potato, tomato, any overly ripe vegetable. I personally can eat potato and sweet potato without any problem and do pretty much every day. Removing tomato was a revelation for me. It’s hard to live around because we use it for so much, but I really feel so much better. I will sometimes have a little for immediately get a stuffy nose and headache. All other vegetables are allowed. Any green that is NOT spinach is allowed. I eat a huge amount of squash, which is a really versatile ingredient. I get lots of different types from supermarkets or farmers’ markets and I make soups, purees, baked squash, squash lasagna, squash steaks, and a million other things. I can always tolerate it. This diet has also pushed me to get familiar with less common ingredients, like taro root, breadfruit and lotus root.

Fruits: Again, the list of fruits that aren’t allowed doesn’t provide any obvious unifying factor to quickly identify something as safe or not. Not allowed: citrus fruits, including lemon and lime; berries, including cranberries, blueberries, blackberries, gooseberries, loganberries, raspberries, strawberries; stone fruits, including apricots, cherries, nectarines, peaches, plums, prunes; bananas, grapes, currants, dates, papayas, pineapples, raisins. Allowed fruits: melons (keep in mind that some people may have an oral allergy syndrome reaction to melons), apple, pear, fig, kiwi, mango, passion fruit, rhubarb, starfruit (not safe for those with impaired kidney function), longans, lychees. I eat a lot of fruit, especially apples and mangoes.

Meat, fish and eggs: All shellfish are prohibited. They naturally have a huge amount of histamine. No processed meats (cold cuts.) Eggs are allowed if they are allowed. Raw egg white is a HUGE histamine liberator. Fish is allowed ONLY IF IT IS FRESHLY CAUGHT, GUTTED AND COOKED. There are differing opinions on what this means but several sources estimate it must be cooked in less than 30 minutes from catching. So unless you are or are married to a fisherman/woman, I think this is unlikely to happen. Any meat should be fresh or thawed from frozen. Leftover meat should not be consumed.

Legumes: Soy is the big culprit here because it’s in everything and is not allowed. Also not allowed: green peas, sugar or sweet peas, red beans and tofu. Everything else is allowed, including lima beans, chickpeas (I eat a ton of chickpeas), pinto beans, white beans, navy beans, black eyed peas, black beans, lentils (I also eat a ton of lentils), split peas, peanuts, and real peanut butter.

Nuts and seeds: All okay except for walnuts and pecans.

Oils: All okay except for oils that contain preservatives like BHA or BHT.

Spices: No anise, cinnamon, clove, curry, cayenne, nutmeg. Everything else is okay.

Sweeteners: No unpasteurized honey, chocolate, cocoa beans, cocoa. Most others are fine, including pasteurized honey, sugar (of really any kind), maple syrup, pure jams and jellies. This diet says plain, artificial sweeteners are okay. They are definitely not for me. One of the very first things I was told by mast cell specialist was not to use artificial sweeteners. So you can judge for yourself.

Drinks: A lot of drinks are restricted, including all teas. Most fruit juices and drinks have some type of unapproved ingredient. Milk, pure juices, water, mineral water and coffee are the allowed drinks. I also sometimes make “muddled” drinks where I crush some safe fruit with a mortar and pestle, make a simple syrup, and then put the muddled fruit in some soda water with some simple syrup.

Miscellaneous: Not allowed: Yeasts, yeast extract, all vinegars, flavored gelatin. Allowed: plain gelatin, cream of tartar, baking soda and baking powder.

The diet recommends a strict four week adherence to determine if it works. I think this is pretty accurate. I did it with no cheating for five weeks. It helped a lot. I slept better, I wasn’t swollen all the time and I was less nauseous. But there were some downsides. The first is that it is a royal pain in the ass if you work because you really have to cook every day. The restrictions on meat meant that I had meat about once every 2-3 weeks. Not everything freezes well so making a lot ahead of time isn’t always a good idea.

Finding recipes can be hard because the fact that they are labelled low histamine does not mean that they ARE low histamine. Please be very careful with that. I also find that some sources for low histamine recipes seem to assume a high level of economic freedom in food purchasing, as well as access to expensive and difficult to find ingredients. I can shop at Whole Foods, which has a knowledgeable staff and a good stock of ingredients for diets like these. There were several components I still cannot find. I also spent literally $1000 at Whole Foods for the five weeks when I initially did this diet.

One unexpected result of this diet was that it resensitized me to foods that I had become desensitized to. So foods that used to bother me a little now cause a severe reaction (sometimes anaphylactic, requiring epinephrine.) I understand that the reason for this is because these foods always caused reactions but I was effectively “used” to them so I didn’t notice. Regardless of the reason, my life is a lot more difficult foodwise than it used to be. I can “cheat” with some foods with medications but the reactions are still bad. I don’t always know how I feel about my choice to do the low histamine diet in my particular situation, but the fact is that since I did, I now am forced to observe a version of it, probably for life.

So that’s my run down on the low histamine diet.

 

 

Lesser known mast cell mediators (Part 3)

Substance P is a neurotransmitter and modulates neurologic responses. It is found in many sensory nerves as well as the brain and spinal cord. It participates in inflammatory responses and is important in pain perception. It is involved in mood disorders, anxiety, stress, nerve growth, respiration, neurotoxicity, nausea, vomiting and pain perception. Its release from nerve fibers into the skin, muscle and joints is thought to cause neurogenic inflammation.

Urocortin is related to corticotropin releasing factor (CRF.) It strongly suppresses blood pressure and increases coronary blood flow. It is thought to have a role in increasing appetite during times of stress.

VEGF-A (vascular endothelial growth factor A) is a member of the platelet derived growth factor (PDGF)/VEGF family. It is important in nerve biology and is the substance mainly involved in inducing growth of blood vessels. It is heavily involved in diseases that involve blood vessels, like diabetic retinopathy and macular degeneration. It is a vasodilator and increases permeability of the smaller vessels.

VIP (vasoactive intestinal peptide) is a small protein like molecule used by nerve cells for communication. It stimulates heart contraction, vasodilation, lowers blood pressure, and relaxes the smooth muscles of the trachea, stomach and gall bladder. It also inhibits gastric acid secretion and absorption in the intestine.

Mast cell kininogenase removes a portion of a compound to release active bradykinin. This is important in the kinin system.

Phospholipase A2 promotes inflammation by initiating formation of arachidonic acid, the precursor needed to form many inflammatory molecules, including prostaglandins. Excessive levels of phospholipase A2 can lead to increased vascular inflammation, such as a seen in coronary artery disease and acute coronary syndrome. Elevated PLA2 is found in the cerebrospinal fluid of people with Alzheimer’s disease and multiple sclerosis.

Corticotropin releasing hormone (CRH) is a hormone and neurotransmitter. High CRH levels have been associated with Alzheimer’s disease and severe depression. CRH is produced in the hypothalamus and is carried to the pituitary gland, where it stimulates secretion of adrenocorticotropic hormone (ACTH.) ACTH drives synthesis of cortisol and other steroids. Imbalance of these hormones can have dire consequences.

Endothelin is the most potent vasoconstrictor currently described. It raises blood pressure and if uncontrolled, hypertension may result. It is involved in many disease processes, including cardiac hypertrophy, type II diabetes and Hirschsprung disease.

Chondroitin is found largely in connective tissues and is a principal component of cartilage. It is typically bound to other components when released from mast cells and interacts with a variety of molecules.

Hyaluronic acid is widely found in epithelial, neural and connective tissues. It participates in a variety of reactions and sees significant turnover daily. When hyaluronic acid is degraded as part of the turnover, its degradation products can cause inflammatory responses.

Lesser known mast cell mediators (Part 2)

Arylsulfatase A, also called cerebroside sulfatase, breaks down compounds to yield cerebrosides and sulfates. Cerebrosides can be either galactocerebrosides, which are found in all tissues of the nervous system; or glucocerebrosides, which are found in the skin, spleen, red blood cells and, to a lesser extent, tissues of the nervous system.

Arylsulfatase B, which has several other names, breaks down large sugar compounds, especially dermatan sulfate and chondroitin sulfate. Arylsulfatase B is mostly found in the liver, pancreas and kidneys.

Mutations in the gene for either arylsulfatase can lead to a variety of heritable disorders, including mucopolysaccharidosis VI and metachromatic leukodystrophy.

Chymases include mast cell protease 1, mast cell serine proteinase, skeletal muscle protease and so on. They are found almost exclusively in mast cells, but are present in small amounts in the granules of basophils. They have several functions, including generating an inflammatory response to parasites. They convert angiotension I to angiotensin II and therefore impact hypertension and atherosclerosis.

Bradykinin causes dilation of blood vessels, which induces a corresponding drop in blood pressure. It achieves its action by triggering release of prostacyclin, nitric oxide and endothelium derived hyperpolarizing factor. It also causes contraction of non-vascular smooth muscles in the respiratory and GI tracts, and is involved in the way the body senses pain. Bradykinin is important in angioedema.

Angiogenin, also called ribonuclease 5, stimulates the formation of new blood vessels. It drives the degradation of the basement membrane and local matrix so that endothelial cells can move toward the vascular spaces.

Leptin is the hormone that regulates hunger. It is mostly produced by fat cells, but is released by mast cells as well. When a specific amount of fat is stored in the body, leptin is secreted and tells the brain that it is full. It opposes the action of ghrelin, the hormone that tells your body it is hungry.

Renin, also called angiotensinogenase, is a critical component of the renin-angiotension system (RAS) that controls the volume of fluids not in cells, including blood plasma, lymph and interstitial fluid. It regulates the body’s mean arterial blood pressure. It converts angiotensinogen to angiotensin I.

Somatostatin, also growth hormone inhibiting hormone (GHIH), regulates the endocrine system, transmission of neurologic signals and cell growth by acting on somatostatin receptors and inhibiting the release of various secondary hormones. It inhibits secretion of glucagon and insulin. It is secreted throughout the GI system and decreases stomach acid production by downregulating the release of gastrin, secretin and histamine.

Lesser known mast cell mediators (Part 1)

I have posted at length about the roles of histamine and serotonin. Here are some less well known mast cell mediators. I will be doing in depth posts on the more relevant substances in the near future.

Monocyte chemotactic protein 1 (MCP-1), also known as chemokine ligand 2 (CCL2), draws other white blood cells, including memory T cells, monocytes and dendritic cells, to the site of injury or infection. It has important functions in neuroinflammation as seen in experimental autoimmune encephalitis, traumatic brain injuries, epilepsy and Alzheimer’s disease; and in diseases with pathologic infiltration of monocytes, like rheumatoid arthritis.

Chemokine ligand 3 (CCP7) recruits monocytes and regulates macrophage activity. It is known to interact with MMP2.

MMP2 (matrix metalloproteinase 2) is involved in tissue remodeling, reproduction and fetal development. It degrades type IV collagen. It has regulatory effects on the menstrual cycle and has been tied to growth of new blood vessels.

Interleukin 8 (IL-8), also known as neutrophil chemotactic factor (NCF), draws other white cells, mostly neutrophils, to a site of infection. It can activate multiple cells types, including mast cells, and promotes degranulation. It has been linked to bronchiolitis, psoriasis and inflammation.

MCP-4 (CCL13) attracts T lymphocytes, eosinophils, monocytes and basophils to an area of inflammation. Improper regulation can exacerbate asthma symptoms. Mast cells can release MCP-1 when stimulated by TNF-a and IL-1.

CCL5 (RANTES) attracts T cells, eosinophils and basophils. When IL-2 and interferon-γ are present, CCL5 activates natural killer cells and causes proliferation of the same. It is also important in bone metabolism.

CCL11 (eotaxin-1) specifically recruits eosinophils and is heavily involved in allergic inflammatory responses.

CPA3 (carboxypeptidase A3) digests proteins. It is released complexed with heparin proteoglycan along with chymase and tryptase.

Both interferon α (IFN- α) and interferon β (IFN-β) are made in response to viral infections. Their activities are regulated by IFN- γ. IFN- γ also draws white cells to the site of inflammation. Failure to properly regulate interferon levels can cause autoimmune disease. Interferons are so called because of their ability to “interfere” with viral infection. They are responsible for “flu type symptoms,” such as fever, muscle aches and lethargy.

All mediators listed here are produced by mast cells and stored in granules until degranulation.

 

MCAS: GI Symptoms and Liver Abnormalities

MCAS patients suffer a variety of GI ailments, which are largely in common with SM.

Aerophagia, excessive swallowing of air, is very common. It is not entirely obvious why this occurs. In other patient populations, aerophagia is usually due to poor coordination between swallowing and respiration. Severe cases can lead to abdominal distention, aspiration of stomach contents into the lungs and esophageal rupture.

Chest discomfort is common in MCAS. Cardiac issues should be ruled out, but in most people, it is due to esophagitis. Some patients have a previous diagnosis of reflux but it is refractory to all relevant treatments.

Diarrhea and constipation, sometimes alternative, are very common. In one study, 89% of MCAS patients studied had frequent nausea, 100% had abdominal pain of some nature, and 69% had noncardiac chest pain. Partial bowel obstructions are uncommon, but do occur in MCAS. They are thought to be due to focal dysmotility or focal edema.

IBS is a frequent previous diagnosis in MCAS. The GI tract often looks normal by eye and typical H&E staining shows mild inflammation. Staining for mast cells often shows they are increased. Of note, there is not a universal consensus on what is considered “increased mast cells” in GI samples. Generally, above 20 cells per hpf is marked as high by pathologists. Presence of the D816V CKIT mutation is rare in GI biopsies of MCAS patients.

Selective malabsorption of certain nutrients is often seen in MCAS. Iron malabsorption is by far the most common. Copper and B vitamins are often poorly absorbed as well. Protein calorie malabsorption is rare, but leads to weight loss and wasting.

Pancreatic enzyme supplementation can be helpful in treatment of diarrhea, weight loss and malabsorption. The fact that this often works suggests that MCAS driven inflammation or fibrosis causes pancreatic exocrine deficiency, a condition in which the pancreas does not make enough digestive enzymes. Mast cells have a known link to painful chronic pancreatitis. In patients with painful vs painless chronic pancreatitis, mast cell density is 3.5X higher in pancreas biopsy.

About half of MCAS patients have some kind of liver abnormality. Fibrosis (obliterative portal venopathy) is the most common. However, fatty metamorphosis, sinusoidal dilatation, venoocclusive dilatation, nodular regenerative hyperplasia and cirrhosis have also been seen. Sterile (non-infectious) inflammation of the liver and portal trial infiltration by lymphocytes and eosinophils has also been identified in a number of patients. In particular, these patients often have a 2-3X elevation in transaminases and/or alkaline phosphatase, determinants of liver function. Impeded flow of bile from the liver is usually absent. Portal hypertension is unusual but has occurred, causing swelling of the spleen and varices in the esophagus. Rarely, free fluid in the abdomen (ascites) has occurred in MCAS patients.

One study found that 75% of MCAS patients tested had high cholesterol levels. Importantly, 79% of patients had “normal” BMI or were underweight, so the high cholesterol was not correlated to weight. 44% had a twofold or greater elevation of liver enzymes. 36% had increased bilirubin in the blood. 15% had fatty liver; 13% had swelling of the liver; 4% had cysts; 4% had adenomas; 2% had hemangiomas. 14% of patients had pancreatic involvement with elevated lipase or amylase.

 

References:

Kirsten Alfter, Ivar von Ku gelgen, Britta Haenisch, Thomas Frieling, Alexandra Hu lsdonk, Ulrike Haars, Arndt Rolfs, Gerhard Noe, Ulrich W. Kolck, Jurgen Homann and Gerhard J. Molderings. New aspects of liver abnormalities as part of the systemic mast cell activation syndrome. 2009 Liver International 29(2): 181-186.

Afrin, Lawrence B. Presentation, diagnosis and management of mast cell activation syndrome. 2011. Mast Cells.

Histamine effects on neurotransmitters (serotonin, dopamine and norepinephrine)

Some of the most important actions of histamine involve regulation of neurotransmitters.  Release of acetylcholine, norepinephrine and serotonin are all controlled in part by histamine levels.  Injection of histamine into the hypothalamus increased metabolism of norepinephrine and serotonin, while dopamine metabolism increased in some places and not in others.  Medications that block the H1 receptor increase dopamine release.  Histamine stimulates prolactin release via the H2 receptor, which in turn inhibits dopamine production.  Histamine can locally increase the concentration of norepinephrine.

Serotonin is a neurotransmitter.  This means that cells nerve cells use this to communicate.  Most of the serotonin in the body is found in the GI tract, where it controls the way the intestine moves food through it.  However, one study indicated that as much as 40% of serotonin in the human body could originate in mast cells.  Serotonin is metabolized to 5-HIAA, which can be tested for as a sign of mast cell activation.
Serotonin released in the GI tract eventually enters the blood stream. On its way to the blood stream, it is taken up by platelets and later used in clotting.   Serotonin is released when eating, which decreases dopamine release and decreases appetite.  If the food consumed is irritating to the GI tract, more serotonin is secreted to move it through the gut faster.  In these situations, the serotonin cannot be fully taken up by platelets and enters the blood stream as free serotonin.  When this happens, it stimulates vomiting.  Some foods contain serotonin, but it does not cross the blood brain barrier and thus does not affect brain chemistry. 
Mast cells contain dopamine, a hormone and neurotransmitter.  This chemical is most often associated with reward seeking behavior, including addiction behaviors.  It also has other important roles, including motor functions.  Mast cell activation causes depletion of dopamine as frequent degranulation causes a decrease in dopamine production by these cells.   Dopamine can be converted to norepinephrine.
In blood vessels, dopamine inhibits norepinephrine release and acts as vasodilator.  Dopamine also increases sodium excretion and urine output, reduces insulin production, reduces GI motility, protects intestinal mucosa and reduces activity of lymphocytes.  It is responsible for cognitive alertness.  If you consider that high histamine levels can decrease dopamine levels, this means that in a mast cell patient, low dopamine levels might cause decreased urine output, increased GI motility and overactivation of white blood cells.  Additionally, low dopamine can translate into higher than normal norepinephrine levels, which could be the link between mast cell disease and POTS.  Brain fog and decreased alertness are effects of low dopamine.
Defective transmission of dopamine is also found in painful conditions like fibromyalgia and restless legs syndrome, associated with mast cell disease.  Activation of D2 dopamine receptors causes nausea and vomiting.  Metoclopramide is a D2 inhibitor and achieves its anti-nausea effects through this mechanism. (Note: metoclopramide can inhibit histamine metabolism and for this reason is not recommended for mast cell patients.)  Some dopaminergic drugs like clozapine, bromocriptine and haloperidol inhibit mast cell degranulation.
Norepinephrine is responsible for concentration and vigilance.  It also increases vascular tone by action on alpha adrenergic receptors.  Norepinephrine is important in the fight or flight response, directly increasing heart rate, triggering release of glucose, increasing blood flow to skeletal muscle and increasing brain oxygen supply.  Interestingly, fasting increases norepinephrine for days.  Glucose intake, but not carbohydrate or protein intake, also increases norepinephrine.  Increased histamine can cause increases in norepinephrine production and secretion.

On prognosis and dying from mast cell disease


There isn’t a lot of data on death from mast cell disease.  Not real data, with statistics and numbers.  People with SM and MCAS are frequently reassured that they will live a normal life span.  People with SM-AHNMD are quoted an average survival of about 8.5 years; ASM, 3.5 years; MCL, under a year. 
Of those groups, only the survival time for mast cell leukemia is convincing to me.  This is because mast cell leukemia has a pretty homogenous presentation, meaning that it affects most people in the same way.  When a disease is as rare as MCL, it is important that you remove as many variables as possible in order for the data to be sound.  And that’s the problem with the rest of the survival data, to my eyes – there’s just too much variability.  Throw in a patient population as small as ours and you’ve got a lot of uncertainty.
The effects of mast cell disease are highly individualized.  There are several B and C findings, meaning that combinations of symptoms and manifestations are very variable.  The SM-AHNMD group is a good example of this.  This category lumps together many different combinations of diseases, not to mention the stages of those diseases.  Someone with ASM-AML is going to have a very different prognosis than someone with SM-CEL.  Simply averaging the lifespans of these people and quoting this as a life expectancy does the mast cell community a disservice.  It is important to remember this when you are typing “mast cell disease death” in the middle of the night. 
Even though we know that most people with SM die from something else, or that for many people, it is a very manageable disease, there is always the possibility that it will be different for you.  It’s hard not to imagine that you will be in the unlucky percentage of people that have progressive disease, that develop ASM, that have leukemic transformation.  Admonishing people who bring up this concern as “negative” or “paranoid” doesn’t make it less terrifying.  It just makes people more afraid to talk about the fact that sometimes people die from mast cell disease and often they aren’t sure how best to minimize their chances of becoming one of them.
Due to the differences in presentation, it has been difficult to identify markers that definitively indicate prognosis.  A lot of effort was put into looking at various CKIT mutations, not just D816V, to see if this could be predictive.  There has not been statistically significant data that this is the case.
The closest things we have to prognostic markers don’t get a lot of play in the general mast cell consciousness.  We talk a lot about CKIT because it affects treatment, and symptoms because it affects diagnosis.  But beyond the initial workup, we don’t often hear much about the CD2 and CD25 markers.  However, a paper published in 2009, established a link between “immunophenotype,” in this case which markers the cells present, and prognosis. 
This study looked at bone marrow samples from 123 patients with different types of SM, including MCL.  Importantly, they also had a large control group of people who did not have SM.  A solid control group is key to determining that a finding is real.  They defined the patients as either good-prognosis (SM, well differentiated SM, and cMAD, clonal mast cell activation disorder (what we now call monoclonal mast cell activation syndrome, MMAS)), or poor-prognosis (ASM and MCL.) 
They determined that for patients whose mast cells expressed BOTH CD25 and CD2 (ISM/MMAS) or NEITHER CD25 and CD2 (WDSM), prognosis was good.  However, mixed expression (typically CD25+ and CD2-) indicated a poorer prognosis.  They compared it to current markers, like the D816V mutation and serum tryptase, as well as clinical findings, like swollen spleen, swollen liver, skin lesions and white blood cell count.  The expression of markers was found to be a sounder method for estimating life expectancy than any of these.
It’s okay to be scared.  We all know people who have died from mast cell disease.  It is scary to think that we could be next.  It is scary to live under the looming threat of anaphylaxis.  But the good news is that science is trying to catch up.  More people are being diagnosed with mast cell disease, and science is getting better at identifying the ways that we are alike and different.  There is every reason to think we will have comforting data in the future.  We just have to get there. 


Reference:
Teodosio, Cristina, et al.  2009.  Mast cells from different molecular and prognostic subtypes of systemic mastocytosis display distinct immunophenotypes.  Journal of Allergy and Clinical Immunology, 125: (3), 719-726.

Effect of anemia on mast cells

A paper released in September 2012 addressed the effect of iron availability on mast cell degranulation.
Inside the bodies of mice, it was observed that mice with decreased iron stores had more severe inflammatory reactions.  Importantly, iron supplementation decreased the severity of the inflammation, particularly in the context of allergic asthma.  Increased iron inhibited the production of inflammatory molecules in pulmonary tissues, including various interleukins and interferons. 
Outside of the body, mast cells were incubated with and without iron for 30 minutes.  IgE was then added to activate the mast cells.  The mast cells that were incubated with iron degranulated 30% less than those without iron present.  Spontaneous degranulation, without IgE crosslinking, was not affected.  The presence of iron also dramatically affected the production of inflammatory molecules by mast cells.  Production of TNF, MCP-1 and IL-6 decreased by 94%, 29% and 27%, respectively.  MCP-1 attracts macrophages. 
Iron supplementation decreased the severity of allergic asthma, and decreased mast cell degranulation by IgE crosslinking 30%, as well as decreasing production of inflammatory molecules by mast cells.

Reference:
Hale LP, Kant EP, Greer PK, Foster WM (2012) Iron Supplementation Decreases Severity of Allergic Inflammation in Murine Lung. PLoS ONE 7(9): e45667. doi:10.1371/journal.pone.0045667