RESUMEN
Coxsackie B virus is primarily associated with fever, pharyngitis, and gastrointestinal symptoms, while myocarditis is rarely reported. We present a rare case of a 47-year-old male with a history of hypertension and obesity, who developed Coxsackie B virus-induced myositis, myocarditis, and polyarthralgia. The patient presented with worsening back pain radiating to his chest, migratory arthralgia, exertional dyspnea, and bilateral shoulder pain with arm weakness. Initial investigations revealed elevated creatinine kinase (CK) levels and troponin I, alongside a high white blood cell (WBC) count and C-reactive protein (CRP) levels. Given the patient's symptoms and uptrending troponin without EKG changes, there was a high concern for non-ST-elevation myocardial infarction (NSTEMI), leading to initial treatment with aspirin and IV heparin. However, further questioning revealed a recent sore throat and contact with an ill family member, prompting investigations for an infectious etiology. A viral panel confirmed Coxsackie B virus infection. The patient made a full recovery with supportive care. This case highlights the importance of considering viral causes, particularly the Coxsackie B virus, in patients presenting with muscle pain, cardiac symptoms, and joint pain. Comprehensive viral testing is crucial for early identification and appropriate management to prevent long-term complications. Understanding the mechanisms of Coxsackie B virus infection is essential for developing effective treatment strategies addressing both the viral infection and the inflammatory response.
RESUMEN
Human genetic studies established MET gene as a risk factor for autism spectrum disorders. We have previously shown that signaling mediated by MET receptor tyrosine kinase, expressed in early postnatal developing forebrain circuits, controls glutamatergic neuron morphological development, synapse maturation, and cortical critical period plasticity. Here we investigated how MET signaling affects synaptic plasticity, learning and memory behavior, and whether these effects are age-dependent. We found that in young adult (postnatal 2-3 months) Met conditional knockout (Metfx/fx:emx1cre, cKO) mice, the hippocampus exhibits elevated plasticity, measured by increased magnitude of long-term potentiation (LTP) and depression (LTD) in hippocampal slices. Surprisingly, in older adult cKO mice (10-12 months), LTP and LTD magnitudes were diminished. We further conducted a battery of behavioral tests to assess learning and memory function in cKO mice and littermate controls. Consistent with age-dependent LTP/LTD findings, we observed enhanced spatial memory learning in 2-3 months old young adult mice, assessed by hippocampus-dependent Morris water maze test, but impaired spatial learning in 10-12 months mice. Contextual and cued learning were further assessed using a Pavlovian fear conditioning test, which also revealed enhanced associative fear acquisition and extinction in young adult mice, but impaired fear learning in older adult mice. Lastly, young cKO mice also exhibited enhanced motor learning. Our results suggest that a shift in the window of synaptic plasticity and an age-dependent early cognitive decline may be novel circuit pathophysiology for a well-established autism genetic risk factor.
Asunto(s)
Envejecimiento/genética , Disfunción Cognitiva/genética , Memoria/fisiología , Plasticidad Neuronal/genética , Neuronas/metabolismo , Proteínas Proto-Oncogénicas c-met/genética , Factores de Edad , Animales , Conducta Animal , Corteza Cerebral , Condicionamiento Clásico/fisiología , Extinción Psicológica , Miedo , Hipocampo/metabolismo , Aprendizaje/fisiología , Potenciación a Largo Plazo/genética , Depresión Sináptica a Largo Plazo/genética , Ratones , Ratones Noqueados , Prueba del Laberinto Acuático de Morris , Aprendizaje Espacial/fisiologíaRESUMEN
Microglia populate the early developing brain and mediate pruning of the central synapses. Yet, little is known on their functional significance in shaping the developing cortical circuits. We hypothesize that the developing cortical circuits require microglia for proper circuit maturation and connectivity, and as such, ablation of microglia during the cortical critical period may result in a long-lasting circuit abnormality. We administered PLX3397, a colony-stimulating factor 1 receptor inhibitor, to mice starting at postnatal day 14 and through P28, which depletes >75% of microglia in the visual cortex (VC). This treatment largely covers the critical period (P19-32) of VC maturation and plasticity. Patch clamp recording in VC layer 2/3 (L2/3) and L5 neurons revealed increased mEPSC frequency and reduced amplitude, and decreased AMPA/NMDA current ratio, indicative of altered synapse maturation. Increased spine density was observed in these neurons, potentially reflecting impaired synapse pruning. In addition, VC intracortical circuit functional connectivity, assessed by laser scanning photostimulation combined with glutamate uncaging, was dramatically altered. Using two photon longitudinal dendritic spine imaging, we confirmed that spine elimination/pruning was diminished during VC critical period when microglia were depleted. Reduced spine pruning thus may account for increased spine density and disrupted connectivity of VC circuits. Lastly, using single-unit recording combined with monocular deprivation, we found that ocular dominance plasticity in the VC was obliterated during the critical period as a result of microglia depletion. These data establish a critical role of microglia in developmental cortical synapse pruning, maturation, functional connectivity, and critical period plasticity.