Not a great way to end 2017
2017 ended with a rejection of the following letter to PNAS.
As a clinical neurologist with a long standing interest in muscular dystrophy(1), I was referred many patients who turned out to have chronic fatigue syndrome (CFS) . Medicine, then and now, has no effective treatment for CFS.
A paper (2) cited In an excellent review of cellular senescence (3) was able to correlate an intracellular marker of senescence (p16^INK4a) with the degree of fatigue experienced by patients undergoing chemotherapy for breast cancer. Chemotherapy induces cellular senescence, and the fatigue was thought to come from the various cytokines secreted by senescent cells (Senescence Associated Secretory Phenotype—SASP) It seems logical to me to test CFS patients for p16^INK4a (4).
I suggested this to the senior author; however, he was nominated as head of the National Cancer Institute just 9 days later. There the matter rested until the paper of Montoya et al. (5) appeared in July. I looked up the 74 individual elements of the SASP and found that 9 were among the 17 cytokines whose levels correlated with the degree of fatigue in CFS. However, this is not statistically significant as Montoya looked at 51 cytokines altogether.
In October, an article(6) on the possibility of killing senescent cells to prevent aging contained a statement that Judith Campisi’s group (which has done much of the work on SASP) had identified “hundreds of proteins involved in SASPs”. (These results have not yet been published.) It is certainly possible that many more of Montoya’s 17 cytokines are among them.
If this is the case, a rational therapy for CFS is immediately apparent; namely, the senolytics, a class of drugs which kills senescent cells. A few senolytics are currently available clinically and many more are under development as a way to attack the aging process (6).
If Montoya still has cells from the patients in the study, measuring p16^INK4a could prove or disprove the idea. However, any oncology service could do the test. If the idea proves correct, then there would be a way to treat the debilitating fatigue of both chemotherapy and CFS—not to mention the many more medical conditions in which severe fatigue is found.
Chemotherapy is a systemic process, producing senescent cells everywhere, which is why DeMaria (2) was able to use circulating blood cells to measure p16^INK4a. It is possible that the senescent cells producing SASP in CFS are confined to one tissue; in which case testing blood for p16^INK4a would fail. (That would be similar to pheochromocytoma cells, in which a few localized cells produce major systemic effects.)
Although senolytics might provide symptomatic treatment (something worthwhile having since medicine presently has nothing for the CFS patient), we’d still be in the dark about what initially caused the cells to become senescent. But this would be research well worth pursuing.
Anyone intrigued by the idea should feel free to go ahead and test it. I am a retired neurologist with no academic affiliation, lacking the means to test it.
References
1 Robinson, L (1979) Split genes and musclar dystrophy. Muscle Nerve 2: 458 – 464
2. He S, Sharpless N (2017) Senescence in Health and Disease. Cell 170: 1000 – 1011
3. Demaria M, et al. (2014) Cellular senescence promotes adverse effects of chemotherapy and cancer relapse. Cancer Discov. 7: 165 – 176
5. Montoya JG, et al., (2017) Cytokine signature associated with disease severity in chronic fatigue syndrome patients, Proc Natl Acad Sci USA 114: E7150-E7158
6. Scudellari M, (2017) To stay young, kill zombie cells Nature 551: 448 – 450
Chemiotics II 