Molecular changes underlying decay of sensory responses and enhanced seizure propensity in peritumoral neurons

Background: Glioblastoma growth impacts on the structure and physiology of peritumoral neuronal networks, altering the activity of pyramidal neurons which drives further tumor progression. It is therefore of paramount importance to identify glioma-induced changes in pyramidal neurons, since they represent a key therapeutic target. Methods: We longitudinal monitored visual evoked potentials after the orthotopic implant of murine glioma cells into the mouse occipital cortex. With laser microdissection we analysed layer II-III pyramidal neurons molecular profile and with Local Field Potentials (LFP) recordings we evaluated the propensity to seizures in glioma-bearing animals with respect to control mice. Results: We determine the time course of neuronal dysfunction of glioma-bearing mice and we identify a symptomatic stage, based on the decay of visual response. At that time point, we microdissect layer II-III pyramidal neurons and evaluate the expression of a panel of genes involved in synaptic transmission and neuronal excitability. Compared to the control group, peritumoral neurons show a decrease in the expression of the SNARE complex gene SNAP-25 and the alpha1 subunit of the GABA-A receptor. No significant changes are detected in glutamatergic (i.e., AMPA or NMDA receptor subunit) markers. Further reduction of GABA-A signalling by delivery of a benzodiazepine inverse agonist, DMCM (methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate) precipitates seizures in two mouse models of tumor-bearing mice. Conclusions: These studies reveal novel molecular changes that occur in the principal cells of the tumor-adjacent zone. These modifications may be therapeutically targeted to ameliorate patients' quality of life

MicroRNAs distribution in different phenotypes of Aortic Stenosis

Aortic valve stenosis (AVS) represents a cluster of different phenotypes, considering gradient and flow pattern. Circulating micro RNAs may reflect specific pathophysiological processes and could be useful biomarkers to identify disease. We assessed 80 patients (81, 76.7-84 years; 46, 57.5%females) with severe AVS. We performed bio-humoral evaluation (including circulating miRNA-1, 21, 29, 133) and 2D-echocardiography. Patients were classified according to ACC/AHA groups (D1-D3) and flow-gradient classification, considering normal/low flow, (NF/LF) and normal/high gradient, (NG/HG). Patients with reduced ejection fractionwere characterized by higher levels of miRNA1 (p = 0.003) and miRNA 133 (p = 0.03). LF condition was associated with higher levels of miRNA1 (p = 0.02) and miRNA21 (p = 0.02). Levels of miRNA21 were increased in patients with reduced Global longitudinal strain (p = 0.03). LF-HG and LF-LG showed higher levels of miRNA1 expression (p = 0.005). At one-year follow-up miRNA21 and miRNA29 levels resulted significant independent predictors of reverse remodeling and systolic function increase, respectively. Different phenotypes of AVS may express differential levels and types of miRNAs, which may retain a pathophysiological role in pro-hypertrophic and pro-fibrotic processes