A definitive mouse study shows that several forms of stress increase multiplication rates of brain immune cells, leading to early senescence in those cell populations, and that leads to damage of neurons and cognitive decline, potentially including Parkinson’s, Alzheimer’s and likely ALS and the other general forms of dementia. This picture will no doubt be clarified by ongoing studies, but I think this looks to be the primary cause of a basket of mental ills know by familiar names that lead to sad outcomes in late life. If this proves to be the mechanism underlying many such ills, a cure (or at least a life-altering delay) is at hand! The researchers used early senolytic drugs Dasatinib + Quercetin to reverse the cognitive decline and to show that it was caused by senescent immune cells and reversed by killing off these cells and eliminating the inflammatory secretions (SASP) by those cells.

You will find informative comments and study excerpts  at FightAging.org (well worth the time to read), and the link to the study paper (PDF). I am posting the Conclusions of the study for your reading below:

“In conclusion, our study revealed that (1) CUS [Chronic Unpredictable Stress] could induce depression-like behaviors and memory impairments in mice, (2) cellular senescence was increased by CUS and had positively correlated with the severity of the memory deficit, (3) the clearance of senescent cells could rescue CUS-induced memory impairment, and (4) CUS could affect the SASP levels. Our proof-of-principle experiments help improve the present understanding of the impact of cellular senescence and demonstrate that therapeutic interventions to clear senescent cells or block their effects may open a new avenue to treat or delay chronic stress-related dysfunctions and improve human health.”

One long-term suggestion within this study is that the Beta-Amyloid and Tau tangles seen in Alzheimer’s and the Alpha-Synuclein in Parkinson’s are merely the stressors that promote rapid multiplication of the brain’s immune cells leading to a progressive rise in senescent cells, and their SASP is what ultimately destroys neurons and prevents their regeneration. If so, we have a new paradigm for healing many mental ills.

To Your Greater Health and Fitness,

Frank