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Month: February 2021

COVID Vaccine in Older Adults

COVID Vaccine in Older Adults

Development of safe and effective vaccines for Covid-19 have been a global priority for thousands of scientists.  Most of the participants in the varied trials are young and middle-aged adults.  This has led to a concern that the good results in younger adults might not apply to older adults.  Older age is a major risk factor for individuals having more severe disease and fatal outcome.  It is also known that in general older adults do not have as robust an immune response to vaccination as do younger adults. 

Emory University just completed a study of the m-RNA-1273 vaccine in older adults with their results being published in the New England Journal of Medicine.  They looked at two age groups:  56-70 years, and greater than 71 years.  Both groups received the recommended initial dose followed by the booster dose 28 days later.

The laboratory markers that were analyzed were assessment of T-cell response, and assessment of neutralizing antibody production.  Both T-cells and antibodies are critical in providing protection against Covid-19.  As it turns out, both age groups had excellent responses in their T-cells and antibodies. 

The other parameter that was studied was adverse events, including: arthralgia, fatigue, fever, chills, headache, muscle ache, nausea, local reaction at injection site, and pain at injection site.  First of all, there were no serious adverse events.  Secondly, the side effects were similar in both groups with two exceptions: the 71 and older group were more likely to experience fatigue and fever than the 56-70 age group. 

These results should be a source of reassurance and comfort to all those baby-boomers out there.

When Bitter is Sweet

When Bitter is Sweet

Asthma affects millions of people worldwide.  The pathophysiology is complex but involves exaggerated smooth muscle contraction in the airways along with inflammation that in a chronic state causes airway remodeling (narrowing).  The majority of current therapies for asthma address these two issues.  Bronchodilators relax the smooth muscles and anti-inflammatories treat the inflammation.  Despite the panoply of these medications there are still many asthmatics who either don’t respond as well as desired or have untoward side effects from the medications. 

Recent research at our local USF has uncovered a new potentially unique mechanism via bitter taste receptors (TAS2R).  Bitter taste receptors are found in many animals, including humans, and are thought to have evolved as a survival mechanism to both sense and avoid potentially harmful food sources.   As it turns out, stimulating these receptors causes airway smooth muscles to relax by a mechanism completely different from currently available bronchodilators. 

It also seems that stimulating TAS2R receptors in the nose and lungs can promote an innate immune response against inhaled irritants and microbes, and can also improve clinical function.  Remember that cilia are the microscopic hairs whose motion helps remove allergens, irritants and microbes from our respiratory system.  So, having the cilia beat more quickly is a good thing.

Of course, this research is very preliminary but the exciting aspect is it may prove to be an extremely safe new approach to treating asthma.  Perhaps Mary Poppins was wrong about “the spoonful of sugar”. 

PPI’s and Mast Cells

PPI’s and Mast Cells

PPI’s aka protein pump inhibitors have been a true God-send for millions of patients with upper gastrointestinal problems: from reflux to gastritis to ulcers.  In large part they have supplanted the previously developed H-2 blockers:  Zantac, Axid, Pepcid and Tagamet. 

Both groups of medicines work by reducing production of the stomach acid, hydrochloric acid.  The chemical formula for this acid is HCI because it is made up of a hydrogen ion (also known as a proton) and a chloride ion.

Now, based on research at Harvard University, PPI’s may have a novel role in treating allergy.  It has been known for quite some time that PPI’s are very helpful in treating a severe form of esophagitis caused by allergy known as eosinophilic esophagitis (EOE).  Until the Harvard studies the reigning theory for the PPI’s benefit was that they controlled excess acid from further injuring the already allergy-inflamed esophagus.  And though this pathophysiology is probably still part of the benefit of the PPI’s it turns out they also exert an effect on the allergic MAST cells.

MAST cells cause allergic inflammation by releasing their cellular contents (contained in granules) including proteases, cytokines, and histamine.  As it turns out PPI’s block some non-gastric proton pumps including the one found inside MAST cells.  Blocking this intracellular proton pump changes the internal pH (acidity) of the MAST cells which interferes with their release of inflammatory molecules.  However, not all PPI’s exert this effect.  To date the only two known to do so are omeprazole and esomeprazole. 

The Harvard researchers hope to extend these findings to find even better ways to “deflate” the MAST cells and their inflammatory granules. 

Dear Dr. K; Can food allergy cause migraines?

Dear Dr. K; Can food allergy cause migraines?

Migraines are caused by genetic makeup but can be precipitated by many factors including food allergy.  The genetic science of migraine is very complex and still evolving.  Suffice it to say that it can be monogenetic or polygenetic.  Monogenetic means a single gene causes the individual to be prone to migraines whereas polygenetic means a whole variety of genes can play a role. 

Migraine headache has a complex physiology that involves vascular (blood vessel) changes, electrical changes, and chemical changes (especially involving neurotransmitters) in the brain.  If an individual inherits genes that impact two or more of these mechanisms then they tend to have greater difficulties with the headaches. 

It has been known for a long time that certain foods can trigger migraines separate from the issue of food allergy.  These foods exert their effect via one of the three mechanisms:  vascular, electrical, or chemical.  And the list includes:  chocolate, cheese, liver, beer, wine, vinegar, nuts, mushrooms, smoked and pickled meat/fish, beef concentrates (bouillon), eggs, yoghurt, soy sauce, MSG and foods containing nitrites (bacon, hot dogs, etc.).

These foods have potential to affect any individual with migraines.  It is probably best to add caffeine to the list in that either withdrawal from caffeine or variations in intake of caffeine can cause migraines. 

With respect to food allergy this would only apply to individuals who are atopic.  And any given food has a potential to precipitate migraine.  The basis for food allergy and migraine is a function of the release of histamines and inflammatory molecules from ingesting the allergic food.

One good way to ferret food-headache issues is to keep a diet/headache diary.  Sometimes its combinations of foods that create a problem, not single exposures.  A diet diary is very helpful in gaining this type of insight.