Reduced bone mineral density is associated to post-TIPS survival of female patients with decompensated cirrhosis.

BACKGROUND: Malnutrition is common in patients with cirrhosis, eventually leading to sarcopenia and loss of bone mass. AIMS: The aims of this study was the assessment of body composition (BC) and bone mineral density (BMD) in patients with decompensated cirrhosis and the prognostic impact on survival after transjugular intrahepatic portosystemic shunt (TIPS) implantation. METHODS: BMD and BC of 107 patients with cirrhosis undergoing TIPS implantation were prospectively analyzed by dual-energy X-ray absorptiometry. The prevalence and predisposing risk factors for reduced BMD and sarcopenia were assessed. Impact on 12-month survival after TIPS implantation was evaluated. RESULTS: Sarcopenia was diagnosed in 48.6 % of the patients with a predominance of male patients (58.7% vs. 25.0 %, p = 0.001). 67.2 % had reduced BMD. Low BMI was independently associated with sarcopenia (OR 0.751 (95 % CI: 0.662;0.852), p < 0.001) and reduced BMD (OR 0.851 (0.773;0.937), p = 0.001). Patients with reduced BMD, but not sarcopenia, had impaired 12-month survival after TIPS-implantation (61.2% vs. 82.9 %, p = 0.030). Subgroup analysis showed that this was especially valid for female patients. CONCLUSIONS: Sarcopenia and reduced BMD are frequently observed in patients with decompensated cirrhosis. Reduced BMD negatively affects post-TIPS survival. Since malnutrition is a leading cause, assessment of nutritional status and specific treatment should be included in clinical practice.

Preserved recovery of cardiac function following ischemia-reperfusion in mice lacking SIRT3.

Lack of the mitochondrial deacetylase sirtuin 3 (SIRT3) impairs mitochondrial function and increases the susceptibility to induction of the mitochondrial permeability transition pore. Because these alterations contribute to myocardial ischemia-reperfusion (IR) injury, we hypothesized that SIRT3 deficiency may increase cardiac injury following myocardial IR. Hearts of 10-week-old mice were perfused in the isolated working mode and subjected to 17.5 min of global no-flow ischemia, followed by 30 min of reperfusion. Measurements before ischemia revealed a decrease in cardiac power (-20%) and rate pressure product (-15%) in SIRT3(-/-) mice. Mitochondrial state 3 respiration (-15%), ATP synthesis (-39%), and ATP/O ratios (-29%) were decreased in hearts of SIRT3(-/-) mice. However, percent recovery of cardiac power (WT 94% ± 9%; SIRT3(-/-) 89% ± 9%) and rate pressure product (WT 89% ± 16%; SIRT3(-/-) 96% ± 3%) following IR was similar in both groups. Myocardial infarct size was not increased in SIRT3(-/-) mice following permanent ligation of the left anterior descending coronary artery (LAD). Left ventricular pressure and dP/dtmax, and mitochondrial respiration and ATP synthesis were not different between groups following LAD ligation. Thus, despite pre-existing defects in cardiac function and mitochondrial respiratory capacity in SIRT3(-/-) mice, SIRT3 deficiency does not additionally impair cardiac function following IR or following myocardial infarction.

SIRT3 deficiency impairs mitochondrial and contractile function in the heart.

Sirtuin 3 (SIRT3) is a mitochondrial NAD(+)-dependent deacetylase that regulates energy metabolic enzymes by reversible protein lysine acetylation in various extracardiac tissues. The role of SIRT3 in myocardial energetics and in the development of mitochondrial dysfunction in cardiac pathologies, such as the failing heart, remains to be elucidated. To investigate the role of SIRT3 in the regulation of myocardial energetics and function SIRT3(-/-) mice developed progressive age-related deterioration of cardiac function, as evidenced by a decrease in ejection fraction and an increase in enddiastolic volume at 24 but not 8 weeks of age using echocardiography. Four weeks following transverse aortic constriction, ejection fraction was further decreased in SIRT3(-/-) mice compared to WT mice, accompanied by a greater degree of cardiac hypertrophy and fibrosis. In isolated working hearts, a decrease in cardiac function in SIRT3(-/-) mice was accompanied by a decrease in palmitate oxidation, glucose oxidation, and oxygen consumption, whereas rates of glycolysis were increased. Respiratory capacity and ATP synthesis were decreased in cardiac mitochondria of SIRT3(-/-) mice. HPLC measurements revealed a decrease of the myocardial ATP/AMP ratio and of myocardial energy charge. Using LC-MS/MS, we identified increased acetylation of 84 mitochondrial proteins, including 6 enzymes of fatty acid import and oxidation, 50 subunits of the electron transport chain, and 3 enzymes of the tricarboxylic acid cycle. Lack of SIRT3 impairs mitochondrial and contractile function in the heart, likely due to increased acetylation of various energy metabolic proteins and subsequent myocardial energy depletion.