MIM-Deficient Mice Exhibit Anatomical Changes in Dendritic Spines, Cortex Volume and Brain Ventricles, and Functional Changes in Motor Coordination and Learning

In this study, we performed a comprehensive behavioral and anatomical analysis of the Missing in Metastasis (Mtss1/MIM) knockout (KO) mouse brain. We also analyzed the expression of MIM in different brain regions at different ages. MIM is an I-BAR containing membrane curving protein, shown to be involved in dendritic spine initiation and dendritic branching in Purkinje cells in the cerebellum. Behavioral analysis of MIM KO mice revealed defects in both learning and reverse-learning, alterations in anxiety levels and reduced dominant behavior, and confirmed the previously described deficiency in motor coordination and pre-pulse inhibition. Anatomically, we observed enlarged brain ventricles and decreased cortical volume. Although MIM expression was relatively low in hippocampus after early development, hippocampal pyramidal neurons exhibited reduced density of thin and stubby dendritic spines. Learning deficiencies can be connected to all detected anatomical changes. Both behavioral and anatomical findings are typical for schizophrenia mouse models.Peer reviewe

Age-dependent vascular changes induced by status epilepticus in rat forebrain: Implications for epileptogenesis

International audienceBrain inflammation, angiogenesis and increased blood-brain barrier (BBB) permeability occur in adult rodent and human epileptogenic brain tissue. We addressed the role of these events in epileptogenesis using a developmental approach since the propensity to develop spontaneous seizures, therefore the induction of epileptogenesis, is age-dependent and increases with brain maturation. Inflammation, angiogenesis and BBB permeability were studied in postnatal day (PN)9 and PN21 rats, 1 week and 4 months after pilocarpineinduced status epilepticus. Brain inflammation was evaluated by interleukin(IL)-1β immunohistochemistry; angiogenesis was quantified by measuring the density of microvessels identified by an anti-laminin antibody or by the intraluminal signal of FITC-albumin; BBB integrity was assessed by extravascular IgG immunostaining or detection of parenchymal extravasation of FITC-albumin. Neither inflammation nor angiogenesis or changes in BBB permeability were detected in PN9 rats after status epilepticus, and these rats did not develop spontaneous seizures in adulthood as assessed by video-EEG monitoring. Differently, status epilepticus in PN21 rats induced chronic inflammation, angiogenesis and BBB leakage in the hippocampus in 62% of rats, while in the remaining rats only transient inflammation in forebrain was observed. Epilepsy developed in about 62% of PN21 rats exposed to SE and these epileptic rats showed the three phenomena concomitantly in the hippocampus. PN21 rats that did not develop epilepsy 4 months after status epilepticus, as assessed by video-EEG monitoring, they did not show inflammation, angiogenesis or BBB damage in forebrain at this time. Our data show that age-dependent vascular changes and brain inflammation induced by status epilepticus are associated with epileptogenesis, suggesting that these phenomena are implicated in the mechanisms underlying the occurrence of spontaneous seizures

Conservative, surgical, and percutaneous treatment for mitral regurgitation shortly after acute myocardial infarction.

AIMS  Severe mitral regurgitation (MR) following acute myocardial infarction (MI) is associated with high mortality rates and has inconclusive recommendations in clinical guidelines. We aimed to report the international experience of patients with secondary MR following acute MI and compare the outcomes of those treated conservatively, surgically, and percutaneously. METHODS AND RESULTS  Retrospective international registry of consecutive patients with at least moderate-to-severe MR following MI treated in 21 centres in North America, Europe, and the Middle East. The registry included patients treated conservatively and those having surgical mitral valve repair or replacement (SMVR) or percutaneous mitral valve repair (PMVR) using edge-to-edge repair. The primary endpoint was in-hospital mortality. A total of 471 patients were included (43% female, age 73 ± 11 years): 205 underwent interventions, of whom 106 were SMVR and 99 PMVR. Patients who underwent mitral valve intervention were in a worse clinical state (Killip class ≥3 in 60% vs. 43%, P < 0.01), but yet had lower in-hospital and 1-year mortality compared with those treated conservatively [11% vs. 27%, P < 0.01 and 16% vs. 35%, P < 0.01; adjusted hazard ratio (HR) 0.28, 95% confidence interval (CI) 0.18-0.46, P < 0.01]. Surgical mitral valve repair or replacement was performed earlier than PMVR [median of 12 days from MI date (interquartile range 5-19) vs. 19 days (10-40), P < 0.01]. The immediate procedural success did not differ between SMVR and PMVR (92% vs. 93%, P = 0.53). However, in-hospital and 1-year mortality rates were significantly higher in SMVR than in PMVR (16% vs. 6%, P = 0.03 and 31% vs. 17%, P = 0.04; adjusted HR 3.75, 95% CI 1.55-9.07, P < 0.01). CONCLUSIONS  Early intervention may mitigate the poor prognosis associated with conservative therapy in patients with post-MI MR. Percutaneous mitral valve repair can serve as an alternative for surgery in reducing MR for high-risk patients