The effects of caloric restriction and a high-fat diet on ovarian lifespan and the expression of SIRT1 and SIRT6 proteins in rats.

BACKGROUND AND AIMS: Caloric restriction (CR) extends mammals' lifespans and suppresses ovary development. Sirtuins are involved in these mechanisms. If, and to what extent CR affects ovarian lifespan and follicle development is largely unknown. We investigated the effects of moderate and severe caloric restriction compared with a high-fat dietary regimen on ovarian follicle reserves in rats. METHODS: Female Sprague-Dawley rats (n=48) randomly divided into four groups including normal control (NC), 25% caloric restriction (MCR), 45% CR (SCR) and high-fat diet (HF) were maintained on these regimens for 2 months. RESULTS: Histological analysis showed that both the 25 and 45% CR rats had a significantly higher percentage of primordial follicles and a larger number of healthy follicles than the NC rats, whereas the HF rats did not differ significantly from the NC rats. Immunohistochemical analysis revealed that SIRT1 and SIRT6 proteins were present in the nucleus and cytoplasm of the oocytes. The 25% CR diet increased the expression of both SIRT1 and SIRT6 in the ovary, whereas the 45% CR and HF diets caused a decrease in SIRT1 expression. The level of SIRT6 protein did not change with the 45% CR diet, and it appeared slightly lower in the HF than in the NC groups. CONCLUSIONS: Caloric restriction may inhibit the transition from primordial to developing follicles and extend the entire growth phase of a follicle to preserve the reserve of germ cells. SIRT1 and SIRT6 are both associated with these effects.

[Reduced cardiopulmonary exercise capacity in patients with essential hypertension: impact of left ventricular hypertrophy].

OBJECTIVE: To evaluate the cardiopulmonary exercise capacity in patients with essential hypertension (EH) complicating with or without left ventricular hypertrophy (LVH). METHODS: Graded maximal exercise test on the bicycle ergometer with respiratory gas analysis were performed in 30 gender and age matched normotensive controls, 40 EH patients without LVH and 30 EH patients with LVH (LVMI>125 g/m2 in males and > 120 g/m2 in females). Metabolic equivalents (METs), oxygen uptake (VO2), oxygen uptake to body mass ratio (VO2/kg) and oxygen uptake to heart beat ratio (VO2/HR) at time of reaching anaerobic threshold (AT) and at maximal oxygen uptake (VO2max) were measured and compared. RESULTS: METs and VO2/kg were significantly reduced in EH patients with or without LVH compared with controls [at AT, METs: 3.57 +/- 0.8 and 4.34 +/- 1.47 vs. 5.21 +/- 1.45; VO2/kg: 12.38 +/- 2.85 and 14.42 +/- 4.33 vs. 18.48 +/- 4.52, all P < 0.01; at VO2max, METs: 4.94 +/- 1.24 and 5.90 +/- 1.51 vs. 6.96 +/- 1.85; VO(2)/kg: (17.20 +/- 4.34) mlxmin(-1)xkg(-1) and (20.41 +/- 4.59) mlxmin(-1)xkg(-1) vs. (24.04 +/- 5.21) mlxmin(-1)xkg(-1), all P < 0.01]. METs and VO2/kg at both time points were also significantly reduced in EH patients with LVH compared EH patients without LVH (all P < 0.05). The lower VO2/kg in hypertensive patients was significantly correlated to higher LVMI (P < 0.05). CONCLUSIONS: Cardiopulmonary exercise capacity was reduced in hypertensive patients, especially in hypertensive patients with LVH.