Microglia control glutamatergic synapses in the adult mouse hippocampus

Microglia cells are active players in regulating synaptic development and plasticity in the brain. However, how they influence the normal functioning of synapses is largely unknown. In this study, we characterized the effects of pharmacological microglia depletion, achieved by administration of PLX5622, on hippocampal CA3-CA1 synapses of adult wild type mice. Following microglial depletion, we observed a reduction of spontaneous and evoked glutamatergic activity associated with a decrease of dendritic spine density. We also observed the appearance of immature synaptic features and higher levels of plasticity. Microglia depleted mice showed a deficit in the acquisition of the Novel Object Recognition task. These events were accompanied by hippocampal astrogliosis, although in the absence ofneuroinflammatory condition. PLX-induced synaptic changes were absent in Cx3cr1−/− mice, highlighting the role of CX3CL1/CX3CR1 axis in microglia control of synaptic functioning. Remarkably, microglia repopulation after PLX5622 withdrawal was associated with the recovery of hippocampal synapses and learning functions. Altogether, these data demonstrate that microglia contribute to normal synaptic functioning in the adult brain and that their removal induces reversible changes in organization and activity of glutamatergic synapses

Contemporary antithrombotic strategies in patients with acute coronary syndromes managed without revascularization: Insights fromthe EYESHOT study

Aims Patients with acute coronary syndromes (ACSs) whoare managed without coronary revascularization represent a mixed and understudied population that seems to receive suboptimal pharmacological treatment. Methods and results We assessed patterns of antithrombotic therapies employed during the hospitalization and in-hospital clinical events of medically managed patients withACS enrolled in the prospective, multicentre, nationwideEYESHOT(EmploYEd antithrombotic therapies in patients with acute coronary Syndromes HOspitalized in Italian cardiac care units) registry.Among the 2585 consecutive ACS patients enrolled in EYESHOT, 783 (30.3%) did not receive any revascularization during hospital admission. Of these, 478 (61.0%) underwent coronary angiography (CA), whereas 305 (39.0%) did not. The median GRACE and CRUSADE risk scores were significantly higher among patients who did not undergo CA compared with those who did (180 vs. 145, P, 0.0001 and 50 vs. 33, P, 0.0001, respectively). Antithrombotic therapies employed during hospitalization significantly differ between patients who received CA and those who did not with unfractioned heparin and novel P2Y12 inhibitors more frequently used in the first group, and low-molecular-weight heparins and clopidogrel in the latter group. During the index hospitalization, patients who did not receive CA presented a higher incidence of ischaemic cerebrovascular events and of mortality compared with those who underwent CA (1.6 vs. 0.2%, P = 0.04 and 7.9 vs. 2.7%, P = 0.0009, respectively). Conclusion Almost one-third of ACS patients are managed without revascularization during the index hospitalization. In this population, a lower use of recommended antiplatelet therapy and worse clinical outcome were observed in those who did not undergo CA when compared with those who did