OSMR and cardiac hypertrophy: Although no notable differences were observed at the basal level, the aggravation of hypertrophy in OSMR-KO hearts was confirmed by ventricular enlargement and cardiac hypertrophy in gross heart morphology, larger individual cardiomyocyte cross-sectional areas and increased ratios of heart weight to body weight or tibia length at 2, 4, and 8 weeks after AB surgery (Fig. 1A–C).