Polyamines Control eIF5A Hypusination, TFEB Translation, and Autophagy to Reverse B Cell Senescence

Failure to make adaptive immune responses is a hallmark of aging. Reduced B cell function leads to poor vaccination efficacy and a high prevalence of infections in the elderly. Here we show that reduced autophagy is a central molecular mechanism underlying immune senescence. Autophagy levels are specifically reduced in mature lymphocytes, leading to compromised memory B cell responses in old individuals. Spermidine, an endogenous polyamine metabolite, induces autophagy in vivo and rejuvenates memory B cell responses. Mechanistically, spermidine post-translationally modifies the translation factor eIF5A, which is essential for the synthesis of the autophagy transcription factor TFEB. Spermidine is depleted in the elderly, leading to reduced TFEB expression and autophagy. Spermidine supplementation restored this pathway and improved the responses of old human B cells. Taken together, our results reveal an unexpected autophagy regulatory mechanism mediated by eIF5A at the translational level, which can be harnessed to reverse immune senescence in humans.

[Percutaneous cervical cordotomy in the therapy of incidence pain]

BACKGROUND

Incident pain does not respond to opioid treatment and it is not easily relieved with other therapeutic strategies (local intrapleural or spinal analgesia, phenol blocks etc.). For this reason cervical percutaneous cordotomy at C(1)-C(2) interspace is the only effective antalgic therapy in patients whose life expectancy is more than three to six months.

METHODS

This study is a rectrospective review of 22 patients with cancer and incident pain from brachial, lumbar-sacral plexus injury and gluteal ulcer.

RESULTS

Cordotomy provided excellent contralateral side pain relief in 21 patients; pain relief was maintained up to death and to the moment of last observation in living patients. In one deaf patient it was impossible to carry out the procedure due to incomplete co-operation and pain returned after 48 hours. Ventilatory depression caused death in one patient. Other complications recorded included ataxia, headache, motor deficit, dysesthesia and orthostatic hypotension.

CONCLUSIONS

The conclusion is drawn that percutaneous cordotomy should, in carefully selected cases, be considered the only technique to relieve incident pain.