No negative impact of reduced leptin secretion on bone metabolism in male decathletes

Abstract

This study investigated the effect of intense physical activities that generate high mechanical constraints on bone metabolism and serum leptin concentrations and the potential relationships among bone mineral density (BMD), bone biochemical markers and leptin variation. Thirteen male decathletes (mean age 22.4 +/- 2.9 years), nationally or internationally ranked (15.5 h/week of training), were compared with 13 healthy sedentary subjects (mean age 25.9 +/- 3.3 years). BMD was measured by DEXA and bone turnover was evaluated by specific markers. Leptin and calciotropic hormones levels were analysed in parallel. BMDs were higher in athletes than in controls at total body (13.9%), lumbar spine (17%), femoral neck (25%) and radius (9%), but not at the head. Athletes presented higher concentrations of osteocalcin (59.8%), cross-linked C-telopeptide of type-I collagen (41.1%) and 1,25-dihydroxyvitamin-D (37.1%). Basal leptin concentration was lower in athletes (0.94 +/- 0.54 vs. 5.07 +/- 1.1 ng ml(-1)), and this difference persisted when leptin levels were adjusted for whole body fat mass (WBFM). No difference was observed for bone-specific alkaline phosphatase or intact parathyroid hormone. Serum leptin levels were negatively correlated with various BMD values only when both the groups were pooled (n = 26). This relationship did not persist when leptin levels were adjusted for WBFM. Male athletes, who practise sports generating high mechanical constraints on the body, present a specific bone metabolism that includes high BMD, as well as high bone turnover. The blunted leptin secretion did not seem to have deleterious effect on the process of bone adaptation to high mechanical constraints.

In peripubertal girls, artistic gymnastics improves areal bone mineral density and femoral bone geometry without affecting serum OPG/RANKL levels

“…Nevertheless, the investigation of different age groups of GYM and CON suggested the course of bone variation throughout the peripubertal period. Moreover, the similar aBMD at the skull, a bone site not affected by mechanical strain [39], adds considerable support to the hypothesis that physical activity is responsible for the bone accretion rather than genetic predisposition [40]. In addition, the higher rate of aBMD gain in young gymnasts compared with non-gymnasts in earlier studies [4,28,41] reinforces the strong effect of physical activity on bone mass acquisition.…”

Hypothalamic leptin gene therapy prevents weight gain without long-term detrimental effects on bone in growing and skeletally mature female rats

“…Species differences in the skeletal response to leptin have been reported. In contrast to mice, reduced leptin signaling is not associated with high bone mass in rats (85,94) or in humans (86,95,96). However, similar effects on weight are observed in mice and rats whether the gene for leptin or the leptin peptide is delivered into the hypothalamus.…”

“…In contrast to mice, reduced leptin signaling is not associated with high bone mass in rats (85,94) or in humans. (86,95,96) However, similar effects on weight are observed in mice and rats whether the gene for leptin or the leptin peptide is delivered into the hypothalamus. Additionally, we reported profound effects of hypothalamic leptin gene therapy on cancellous bone mass in lumbar vertebrae as well as total bone mass and femoral length of growing leptin-deficient ob/ob mice.…”

Seasonal variation of bone turnover markers in top-level female skiers

“…The effects of physical activity on bone density can be evaluated by direct measurement of BMD by means of radiological methods at different sites (Morel et al 2001;McClanahan et al 2002;Bemben et al 2004;Maïmoun et al 2008;Rector et al 2008); however, this kind of response takes several months or years before even the most precise method can detect it. Acute responses can be assessed by measuring the serum level of biochemical markers of bone turnover which reflect the cellular events involved in bone metabolism (Brahm et al 1996;Seibel 2005).…”