Sepsis is one of the key things that interferes with the pyruvate dehydrogenase enzyme
That's very interesting dannybex, I did not know that.
It says
here that sepsis promotes an increase in
pyruvate dehydrogenase kinase, which in turn reduces inhibits
pyruvate dehydrogenase, a crucial enzyme in aerobic glycolysis (pyruvate dehydrogenase kinase acts as an inhibitor of pyruvate dehydrogenase).
Fluge and Mella of course found an increased expression of pyruvate dehydrogenase kinases in ME/CFS patients, which they think might explain the low energy state of ME/CFS.
That makes me wonder whether the mechanism which down-regulates pyruvate dehydrogenase kinase in sepsis might be the same fundamental mechanism causing ME/CFS.
Dr Bell posited that
ME/CFS may be a sort of "slow sepsis":
Dr. David Bell proposed that patients with ME/CFS have what he called "slow sepsis." In his monograph,
Cellular Hypoxia and Neuro-Immune Fatigue, he suggests that ME/CFS is a slow, chronic form of septic shock.
The sequence of events in septic shock is: 1) a serious infection, 2) production of cytokines, 3) increased nitric oxide, and 4) interference with the production of cellular energy. In severe cases of septic shock, the loss of cellular energy is so profound that it can be fatal.
Source:
here
We know of course that ME/CFS is associated with chronic low-level "smoldering" enterovirus infections in the tissues, thus the idea of ME/CFS being a slow sepsis is not unreasonable.
So if ME/CFS is a slow sepsis, and since sepsis increases pyruvate dehydrogenase kinase and inhibits pyruvate dehydrogenase, this slow sepsis theory could explain Fluge and Mella's findings, and could be the core pathophysiology of ME/CFS.
I can't seem to find at the moment the mechanism by which sepsis down-regulates pyruvate dehydrogenase, and the cytokines or other messenger molecules that might be involved in this down-regulation; but that mechanism could conceivably be the key to understanding ME/CFS.
However,
this paper says that the cytokine IL-6 is a marker of the severity of sepsis, so IL-6 might be an important player in sepsis. And interestingly enough,
this paper finds that in mice, IL-6 inhibits pyruvate dehydrogenase in skeletal muscle. So possibly IL-6 might be involved in the pyruvate dehydrogenase inhibition Fluge and Mella found in ME/CFS (some studies have found IL-6 raised in ME/CFS, and
huge quantities of IL-6 are released by the muscles during exercise, since IL-6 is also a myokine, which might perhaps explain PEM).
Some Notes on Terminology
Bacteremia = the presence of bacteria in the bloodstream (which can temporarily occur in a non-dangerous way when you brush your teeth).
Septicemia = the presence
and multiplication of bacteria in the blood (which is more dangerous than bacteremia). Septicemia is also known as blood poisoning.
Systemic inflammatory response syndrome (SIRS) = a dysregulated inflammatory state affecting the whole body, usually (but not always) in response to infection. SIRS is a type of cytokine storm, in which there is abnormal regulation of cytokines.
Sepsis = SIRS caused by septicemia or by another infection in the body, resulting in injury to body tissues and organs. Usually the infection is bacterial, but it may also be fungal, viral or parasitic.
Septic shock = the dangerously low blood pressure that can occur during sepsis.