Microglial P2Y12 receptor regulates ventral hippocampal CA1 neuronal excitability and innate fear in mice

The P2Y12 receptor (P2Y12R) is a purinoceptor that is selectively expressed in microglia in the central nervous system. As a signature receptor, microglial P2Y12R mediates process chemotaxis towards ADP/ATP gradients and is engaged in several neurological diseases including chronic pain, stroke and seizures. However, the role of microglial P2Y12R in regulating neuronal excitability and innate behaviors is not fully understood. Here, we generated P2Y12-floxed mice to delete microglial P2Y12R beginning in development (CX3CR1Cre/+:P2Y12f/f; “constitutive knockout”), or after normal development in adult mice (CX3CR1CreER/+:P2Y12f/f; “induced knockout”). Using a battery of behavioral tests, we found that both constitutive and induced P2Y12R knockout mice exhibited innate fear but not learned fear behaviors. After mice were exposed to the elevated plus maze, the c-fos expression in ventral hippocampus CA1 neurons was robustly increased in P2Y12R knockout mice compared with wild-type mice. Consistently, using whole cell patch clamp recording, we found the excitability of ventral hippocampus CA1 neurons was increased in the P2Y12R knockout mice. The results suggest that microglial P2Y12R regulates neuronal excitability and innate fear behaviors in developing and adult mice

Microglial P2Y12 receptor regulates ventral hippocampal CA1 neuronal excitability and innate fear in mice

The P2Y12 receptor (P2Y12R) is a purinoceptor that is selectively expressed in microglia in the central nervous system. As a signature receptor, microglial P2Y12R mediates process chemotaxis towards ADP/ATP gradients and is engaged in several neurological diseases including chronic pain, stroke and seizures. However, the role of microglial P2Y12R in regulating neuronal excitability and innate behaviors is not fully understood. Here, we generated P2Y12-floxed mice to delete microglial P2Y12R beginning in development (CX3CR1Cre/+:P2Y12f/f; “constitutive knockout”), or after normal development in adult mice (CX3CR1CreER/+:P2Y12f/f; “induced knockout”). Using a battery of behavioral tests, we found that both constitutive and induced P2Y12R knockout mice exhibited innate fear but not learned fear behaviors. After mice were exposed to the elevated plus maze, the c-fos expression in ventral hippocampus CA1 neurons was robustly increased in P2Y12R knockout mice compared with wild-type mice. Consistently, using whole cell patch clamp recording, we found the excitability of ventral hippocampus CA1 neurons was increased in the P2Y12R knockout mice. The results suggest that microglial P2Y12R regulates neuronal excitability and innate fear behaviors in developing and adult mice

The “Hypertension Approaches in the Elderly: a Lifestyle study” multicenter, randomized trial (HAEL Study): rationale and methodological protocol

Background: Hypertension is a clinical condition highly prevalent in the elderly, imposing great risks to cardiovascular diseases and loss of quality of life. Current guidelines emphasize the importance of nonpharmacological strategies as a first-line approach to lower blood pressure. Exercise is an efficient lifestyle tool that can benefit a myriad of health-related outcomes, including blood pressure control, in older adults. We herein report the protocol of the HAEL Study, which aims to evaluate the efficacy of a pragmatic combined exercise training compared with a health education program on ambulatory blood pressure and other health-related outcomes in older individuals. Methods: Randomized, single-blinded, multicenter, two-arm, parallel, superiority trial. A total of 184 subjects (92/center), ≥60 years of age, with no recent history of cardiovascular events, will be randomized on a 1:1 ratio to 12-week interventions consisting either of a combined exercise (aerobic and strength) training, three times per week, or an active-control group receiving health education intervention, once a week. Ambulatory (primary outcome) and office blood pressures, cardiorespiratory fitness and endothelial function, together with quality of life, functional fitness and autonomic control will be measured in before and after intervention. Discussion: Our conceptual hypothesis is that combined training intervention will reduce ambulatory blood pressure in comparison with health education group. Using a superiority framework, analysis plan prespecifies an intention-to-treat approach, per protocol criteria, subgroups analysis, and handling of missing data. The trial is recruiting since September 2017. Finally, this study was designed to adhere to data sharing practices. Trial registration: NCT03264443. Registered on 29 August, 2017

Exercise in type 2 diabetes: to resist or to endure?

There is now evidence that a single bout of endurance (aerobic) or resistance exercise reduces 24 h post-exercise subcutaneous glucose profiles to the same extent in insulin-resistant humans with or without type 2 diabetes. However, it remains to be determined which group would benefit most from specific exercise protocols, particularly with regard to long-term glycaemic control. Acute aerobic exercise first accelerates translocation of myocellular glucose transporters via AMP-activated protein kinase, calcium release and mitogen-activated protein kinase, but also improves insulin-dependent glucose transport/phosphorylation via distal components of insulin signalling (phosphoinositide-dependent kinase 1, TBC1 domain family, members 1 and 4, Rac1, protein kinase C). Post-exercise effects involve peroxisome-proliferator activated receptor-γ coactivator 1α and lead to ATP synthesis, which may be modulated by variants in genes such as NDUFB6. While mechanisms of acute resistance-type exercise are less clear, chronic resistance training activates the mammalian target of rapamycin/serine kinase 6 pathway, ultimately increasing protein synthesis and muscle mass. Over the long term, adherence to rather than differences in metabolic variables between specific modes of regular exercise might ultimately determine their efficacy. Taken together, studies are now needed to address the variability of individual responses to long-term resistance and endurance training in real life

Microglia Are Indispensable for Synaptic Plasticity in the Spinal Dorsal Horn and Chronic Pain

Spinal long-term potentiation (LTP) at C-fiber synapses is hypothesized to underlie chronic pain. However, a causal link between spinal LTP and chronic pain is still lacking. Here, we report that high-frequency stimulation (HFS; 100 Hz, 10 V) of the mouse sciatic nerve reliably induces spinal LTP without causing nerve injury. LTP-inducible stimulation triggers chronic pain lasting for more than 35 days and increases the number of calcitonin gene-related peptide (CGRP) terminals in the spinal dorsal horn. The behavioral and morphological changes can be prevented by blocking NMDA receptors, ablating spinal microglia, or conditionally deleting microglial brain-derived neurotrophic factor (BDNF). HFS-induced spinal LTP, microglial activation, and upregulation of BDNF are inhibited by antibodies against colony-stimulating factor 1 (CSF-1). Together, our results show that microglial CSF1 and BDNF signaling are indispensable for spinal LTP and chronic pain. The microglia-dependent transition of synaptic potentiation to structural alterations in pain pathways may underlie pain chronicity

Therapeutic Validity and Effectiveness of Preoperative Exercise on Functional Recovery after Joint Replacement: A Systematic Review and Meta-Analysis

Background: Our aim was to develop a rating scale to assess the therapeutic validity of therapeutic exercise programmes. By use of this rating scale we investigated the therapeutic validity of therapeutic exercise in patients awaiting primary total joint replacement (TJR). Finally, we studied the association between therapeutic validity of preoperative therapeutic exercise and its effectiveness in terms of postoperative functional recovery. Methods: (Quasi) randomised clinical trials on preoperative therapeutic exercise in adults awaiting TJR on postoperative recovery of functioning within three months after surgery were identified through database and reference screening. Two reviewers extracted data and assessed the risk of bias and therapeutic validity. Therapeutic validity of the interventions was assessed with a nine-itemed, expert-based rating scale (scores range from 0 to 9; score ≥6 reflecting therapeutic validity), developed in a four-round Delphi study. Effects were pooled using a random-effects model and meta-regression was used to study the influence of therapeutic validity. Results: Of the 7,492 articles retrieved, 12 studies (737 patients) were included. None of the included studies demonstrated therapeutic validity and two demonstrated low risk of bias. Therapeutic exercise was not associated with 1) observed functional recovery during the hospital stay (Standardised Mean Difference [SMD]: −1.19; 95%-confidence interval [CI], −2.46 to 0.08); 2) observed recovery within three months of surgery (SMD: −0.15; 95%-CI, −0.42 to 0.12); and 3) self-reported recovery within three months of surgery (SMD −0.07; 95%-CI, −0.35 to 0.21) compared with control participants. Meta-regression showed no statistically significant relationship between therapeutic validity and pooled-effects. Conclusion: Preoperative therapeutic exercise for TJR did not demonstrate beneficial effects on postoperative functional recovery. However, poor therapeutic validity of the therapeutic exercise programmes may have hampered potentially beneficial effects, since none of the studies met the predetermined quality criteria. Future review studies on therapeutic exercise should address therapeutic validity. (aut.ref.