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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, METHODS, RESULTS. Meshes: Animals, Dog Diseases, Dogs, Down-Regulation, Female, Heart Valve Diseases, Immunoblotting, Male, Mitral Valve, Serotonin, Serotonin Plasma Membrane Transport Proteins.
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Is serotonin transmembrane transporter down-regulated in late-stage canine degenerative mitral valve disease? Context: To compare expression of the serotonin transmembrane transporter (SERT) in normal, early-stage degenerative, and late-stage degenerative canine mitral valve disease. 24 post-mortem canine mitral valves. SERT expression was determined in canine normal (n = 8), early-stage degenerative (n = 8), and late-stage degenerative (n = 8) mitral valves by immunohistochemistry (IHC) and immunoblot (IB) analyses. SERT was expressed in valve interstitial cells of all layers of normal and early-stage degenerative mitral valves based on IHC. SERT was markedly down-regulated in valve interstitial cells, but not valve endothelial cells, of late-stage degenerative mitral valves. SERT expression was significantly decreased in late-stage compared to normal and early-stage degenerative mitral valves based on IB analysis (P < 0.05).
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Down-regulation of SERT expression occurs in valve interstitial cells of late-stage, but not early-stage, canine degenerative mitral valves. Down-regulation of SERT could enhance the recently speculated role of serotonin in canine DMVD by decreasing serotonin metabolism and increasing interaction with its receptor. Down-regulation of SERT likely does not play an initiating role in canine DMVD since it does not occur in early-stage disease. Final Decision: yes