When “Zombie Cells” Cause Chronic Inflammation

There is a tendency for us to have progressive inflammatory activity as we age.  This inflammation is a part of virtually every chronic disease from heart disease to cancer to autoimmune disease.  As would be expected all of these diseases become progressively more common with age in parallel to what is happening with inflammation.  This process of progressive inflammation with age has been termed inflammaging.

There is a tendency to think that the common “with age” means no need to be concerned about this until age 60 or 70.  The reality is that all of these processes associated with aging begin between the 3rd and 4th decades.  This is also the best time to take measures to limit these processes such as inflammation before significant damage is done.

Intensive research is going on concerning this process of inflammaging which is involved in so many diseases.  Searching this topic on PubMed, the search engine for the National Library of Medicine shows over 1300 studies on this topic.  Highlighting how this is a new understanding, the majority of these studies were published after 2010 and no studies predated 2000.

One of the important mechanisms of this progressive inflammation are old immune cells which no longer function fully but have not been eliminated as should happen to old, non-functioning cells.  Components in cells such as mitochondria, the bodies that produce cell energy, burn out and no longer function properly. 

These non-functioning internal bodies ideally are eliminated from the cell by degrading enzymes, a process called autophagy which means “self-eating”.  Removal of these non-functioning internal bodies often restores function of the cell as a whole.  With inflammaging this process does not occur, and these dysfunctioning pieces within the immune cells pump out inflammatory activating cytokines creating a chronic, low-grade inflammation.

These dysfunctioning immune cells have been affectionately called “zombie cells” by immunology researchers.  They literally are the walking dead of the cells in an otherwise live human.  Two areas of treatment of this chronic, low-grade inflammation have arisen.  The first is stimulating the cell to clean out these non-functional internal bodies by autophagy.  The second is to stimulate the removal of these inflammation generating cells if autophagy does not restore their normal function.  This is a process of apoptosis or “program cell death”.

Drug development in this area to stimulate both autophagy to remove the older, non-functioning mitochondria and apoptosis to remove zombie cells whose function cannot be restored, is a keen area in research.  This approach is being used to treat many conditions involving inflammation and immune dysfunction such as cancer, pulmonary fibrosis and Alzheimer’s disease.  These drugs are called senolytics referring to targeting the “zombie or senile” cells. Dasatinib is one drug that has shown promise.

In a somewhat more practical approach, two dietary flavonoids have shown equal promise, quercetin and fisetin.  Quercetin is broadly available in many plant foods such as onions, apples, grapes, berries, broccoli, citrus fruits, cherries, green tea, coffee, red wine, capers and tea.  Fisetin is present in strawberries, persimmon and grapes as well as several other plants.  Although these two phytonutrients have been the most studied, large numbers of the 18,000 identified phytonutrients have similar properties.

The natural plan seems to be that the factors we would need to control the build-up of inflammation and disease-causing zombie cells are spread across a variety of healthy plants foods.  To get this protection we need to eat a broad spectrum of healthy plant foods, something that has declined in the U.S. diet as the diseases of aging have increased.

For most of our time on the planet seasonal eating was necessary.  In the northeast where I grew up, we ate strawberries for the 4 weeks they were in season and then moved on to the summer melons and fall apples.  The same change and variety of vegetables was part of life.  Now many eat only a limited variety of plants all year as plants are grown in other areas of the world and shipped to us.  Doing so misses the important diversity of plants and phytonutrients that are important for health with aging.

A great way to reconnect with diverse plant eating is to join a CSA or community supported agriculture group.  These typically supply a weekly box of fresh vegetables and fruits.  The content changes as different plants are in season ensuring a spectrum of phytonutrients.