Katsuhiko Ohori

Ser9 phosphorylation of mitochondrial GSK-3β is a primary mechanism of cardiomyocyte protection by erythropoietin against oxidant-induced apoptosis

The aim of this study was to determine the role of GSK-3beta in cardiomyocyte protection afforded by erythropoietin (EPO) against oxidant stress-induced apoptosis. Treatment with EPO (10 units/ml) induced Ser473 phosphorylation of Akt and Ser9 phosphorylation of GSK-3beta and significantly reduced the proportion of apoptotic H9c2 cardiomyocytes after exposure to H2O2 from 38.3 +/- 2.7% to 26.0 +/- 2.9%. This protection was not detected in cells transfected with constitutively active GSK-3beta (S9A), which lacks Ser9 for inhibitory phosphorylation. The antiapoptotic effect of EPO was mimicked completely by GSK-3beta knockdown using small interfering RNA and partly by the transfection with kinase-deficient GSK-3beta (K85R). The level of colocalization of intracellular GSK-3beta with mitochondria assessed by enhanced green fluorescent protein-tagged GSK-3beta or immunocytochemistry was not altered by EPO treatment. However, EPO increased the level of Ser9-phospho-GSK-3beta colocalized with mitochondria by 50% in a phosphatidylinositol 3-kinase-dependent manner. Mitochondrial translocation of Bcl-2-associated X protein (BAX) after exposure to H2O2 was inhibited by EPO pretreatment and by GSK-3beta knockdown. These results suggest that the suppression of GSK-3beta activity by Akt-mediated Ser9 phosphorylation in the mitochondria affords cardiomyocytes tolerance against oxidant-induced apoptosis, possibly by inhibiting the access of BAX to the mitochondria.

Nutritional Status and Energy Intake as Predictors of Functional Status After Cardiac Rehabilitation in Elderly Inpatients With Heart Failure ― A Retrospective Cohort Study ―

BACKGROUND Whether the short-term effect of cardiac rehabilitation (CR) in elderly patients with heart failure (HF) is influenced by nutritional status is uncertain, so the present study investigated the effect of nutritional status on functional recovery after CR in elderly HF inpatients.Methods and Results:We enrolled 145 patients admitted for treatment of HF who were aged ≥65 years and had a low functional status defined as a Barthel index (BI) score ≤85 points at the commencement of CR. Nutritional status was assessed by the Mini Nutritional Assessment Short Form (MNA-SF) and total energy intake per day. The primary endpoint was functional status determined by the BI score at discharge. The median CR period was 20 days (interquartile range: 14-34 days), and 87 patients (60%) were functionally dependent (BI score ≤85) at discharge. Multivariate logistic regression analysis showed that MNA-SF score (odds ratio [OR]: 0.76, P=0.02) and total energy intake at the commencement of CR (OR: 0.91, P=0.02) were independent predictors of functional dependence after CR. MNA-SF score ≤7 and total energy intake ≤24.5 kcal/kg/day predicted functional dependence at discharge with moderate sensitivity and specificity. CONCLUSIONS MNA-SF score and total energy intake at the commencement of CR are novel predictors of the extent of functional recovery of elderly HF inpatients after in-hospital CR.