Exercised blood plasma promotes hippocampal neurogenesis in the Alzheimer's disease rat brain

Background:Exercise training promotes brain plasticity and is associated with protection against cognitive impairment and Alzheimer’s disease(AD).These beneficial effects may be partly mediated by blood-borne factors.Here we used an in vitro model of AD to investigate effects of blood plasma from exercise-trained donors on neuronal viability,and an in vivo rat model of AD to test whether such plasma impacts cognitive function,amyloid pathology,and neurogenesis.Methods:Mouse hippocampal neuronal cells were exposed to AD-like stress using amyloid-βand treated with plasma collected from human male donors 3 h after a single bout of high-intensity exercise.For in vivo studies,blood was collected from exercise-trained young male Wistar rats(high-intensity intervals 5 days/week for 6 weeks).Transgenic AD rats(McGill-R-Thyl-APP)were inj ected 5 times/fortnight for 6 weeks at2 months or 5 months of age with either(a)plasma from the exercise-trained rats,(b)plasma from sedentary rats,or(c)saline.Cognitive function,amyloid plaque pathology,and neurogenesis were assessed.The plasma used for the treatment was analyzed for 23 cytokines.Results:Plasma from exercised donors enhanced cell viability by 44.1%(p=0.032)and reduced atrophy by 50.0%(p<0.001)in amyloid-β-treated cells.In vivo exercised plasma treatment did not alter cognitive function or amyloid plaque pathology but did increase hippocampal neurogenesis by~3 fold,regardless of pathological stage,when compared to saline-treated rats.Concentrations of 7 cytokines were significantly reduced in exercised plasma compared to sedentary plasma.Conclusion:Our proof-of-concept study demonstrates that plasma from exercise-trained donors can protect neuronal cells in culture and promote adult hippocampal neurogenesis in the AD rat brain.This effect may be partly due to reduced pro-inflammatory signaling molecules in exercised plasma.

Convalescent plasma: A potential therapeutic option for COVID-19 patients

The new coronavirus disease(COVID-19)outbreak has challenged us to take unprecedented steps to bring this pandemic under control.In view of the urgency of this situation,convalescent plasma which was used in previous coronavirus outbreaks has emerged as one of the treatment options in this current pandemic.This is mainly due to the fact that convalescent plasma has been studied in a few case series with promising outcomes.In addition,on-going large clinical trials aimed to further evaluate the effectiveness,safety,and optimal dosage,duration and timing of administration of convalescent plasma are indeed revealing a certain level of promising results.Therefore,this article aims to provide an overview of possible mechanisms of actions of convalescent plasma,its benefits and its level of usage safeness by summarizing the existing evidence on the use of convalescent plasma in COVID-19 patients.

Young blood products:emerging treatment for Alzheimer's disease?

Alzheimer＇s disease is the most common neurodegenerative disorder and no disease-modifying treatment is currently available.Research has shown that while brain neurogenesis continues in adult life,it declines with age.Using parabiosis,plasma transfusions and direct administration of neural growth factors,animal studies have demonstrated the positive impact of exposure to young blood products on neurogenesis and synaptic plasticity in an aging brain.The hippocampus and the sub-ventricular zones were identified as the main regions affected.Promising findings have prompted researchers to experiment their effects in subjects with an established neurocognitive disorder,such as Alzheimer＇s disease.They argued that modification of brain vasculature,reactivation of adult neural stem cells,and remodeling of their synaptic activity/plasticity may lead to cognitive enhancement and increased neurogenesis.One pilot human study found that young donor plasma infusion protocols for adults with Alzheimer＇s disease were safe and feasible;however,no statistically significant improvements in cognition were detected.There is a need to conduct additional placebo-controlled human studies in larger samples.Future studies should focus on identifying an “optimal age” at which an intervention in humans may yield significant cognitive enhancement,as well as determining the types of transfusions with the best efficacy and tolerability profiles.