The bone-adipose axis in obesity and weight loss

Effects of diet-induced obesity and voluntary wheel running on the microstructure of the murine distal femur

Background

Obesity and osteoporosis, two possibly related conditions, are rapidly expanding health concerns in modern society. Both of them are associated with sedentary life style and nutrition. To investigate the effects of diet-induced obesity and voluntary physical activity we used high resolution micro-computed tomography (μCT) together with peripheral quantitative computed tomography (pQCT) to examine the microstructure of the distal femoral metaphysis in mice.

Methods

Forty 7-week-old male C57BL/6J mice were assigned to 4 groups: control (C), control + running (CR), high-fat diet (HF), and high-fat diet + running (HFR). After a 21-week intervention, all the mice were sacrificed and the left femur dissected for pQCT and μCT measurements.

Results

The mice fed the high-fat diet showed a significant weight gain (over 70% for HF and 60% for HFR), with increased epididymal fat pad mass and impaired insulin sensitivity. These obese mice had significantly higher trabecular connectivity density, volume, number, thickness, area and mass, and smaller trabecular separation. At the whole bone level, they had larger bone circumference and cross-sectional area and higher density-weighted maximal, minimal, and polar moments of inertia. Voluntary wheel running decreased all the cortical bone parameters, but increased the trabecular mineral density, and decreased the pattern factor and structure model index towards a more plate-like structure.

Conclusions

The results suggest that in mice the femur adapts to obesity by improving bone strength both at the whole bone and micro-structural level. Adaptation to running exercise manifests itself in increased trabecular density and improved 3D structure, but in a limited overall bone growth

Circulating osteocalcin concentrations are associated with parameters of liver fat infiltration and increase in parallel to decreased liver enzymes after weight loss

SUMMARY

The expression of liver genes was associated with insulin action in osteocalcin knockout mice. Our findings suggest that osteocalcin may play a role in the development of insulin resistance-associated fatty liver disease.

INTRODUCTION

The expression of insulin target genes was decreased in the liver of mice lacking osteocalcin. We aimed to explore the association of liver enzymes with osteocalcin.

METHODS

The associations were evaluated in a cross-sectional study (266 men) and following weight loss in 28 obese subjects (nine male, 19 females).

RESULTS

In the cross-sectional study, circulating osteocalcin concentration was negatively associated with alanine transaminase (ALT) (p = 0.002) and aspartate transaminase (AST) levels (p = 0.008). These associations were especially significant in non-obese subjects (n = 191). In a multiple linear regression analysis, age (p = 0.008), insulin sensitivity (p = 0.001), and osteocalcin (p = 0.04) independently contributed to 22% of ALT variance in these latter subjects. In the weight loss study, the increase in circulating osteocalcin concentration (+70.6 ± 29.3 vs. +32 ± 13.5%, p = 0.021) was significantly greater in subjects with the highest decrease in ALT levels, despite similar baseline BMI, insulin resistance and degree of weight loss than remaining subjects. In fact, the change in ALT levels were linearly associated with those of osteocalcin (r = -0.55, p = 0.003).

CONCLUSIONS

In summary, our findings suggest a bone-liver axis in which osteocalcin might be the active regulator.

Vitamin D status and supplementation in morbid obesity before and after bariatric surgery

Interest in vitamin D has increased recently because of its role on multiple biologic mechanisms and the high prevalence of deficits, particularly in obese individuals. The epidemic of morbid obesity has led to a growing number of bariatric surgical procedures, the only therapeutic modality with a reasonable chance of success on a long-term basis. Vitamin D status following bariatric surgery depends on several interacting factors and should be monitored carefully. We review vitamin D, calcium and parathyroid hormone dynamics following the main types of bariatric surgery and the guidelines for the postoperative periodic assessment and therapy.

Bone metabolism markers in sports medicine

Bone mass can be viewed as the net product of two counteracting metabolic processes, bone formation and bone resorption, which allow the skeleton to carry out its principal functions: mechanical support of the body, calcium dynamic deposition and haemopoiesis. Besides radiological methods, several blood and urinary molecules have been identified as markers of bone metabolic activity for estimating the rates and direction of the biological activities governing bone turnover. The advantages for the use of bone metabolism markers are that they are potentially less dangerous than radiological determinations, are more sensitive to changes in bone metabolism than radiological methods and are easily collected and analysed. The disadvantages are that they have high biological variability. Physical exercise is a known source of bone turnover and is recommended for preventing osteoporosis and bone metabolism problems. There are numerous experiments on bone metabolism markers after acute exercise, but not after long-term training and during or after a whole competition season. Moreover, few studies on bone metabolism markers have evaluated their performance in elite and top-level athletes, who have a higher bone turnover than sedentary individuals. Despite discrepant results among studies, most have shown that short exercise is insufficient for modifying serum concentrations of bone metabolism markers. Marker variations are more evident after several hours or days after exercise, bone formation markers are more sensitive than bone resorption markers, and stimulation of osteoblast and/or osteoclast functions is exercise dependent but the response is not immediate. The response depends on the type of exercise; the markers seem to be less sensitive to resistance exercise and the intensity of exercise is not discriminate. Comparisons between trained subjects and untrained controls have demonstrated the influence of exercise on bone turnover. During training, carboxy-terminal collagen cross-links (CTx), a bone resorption marker, was shown to be less sensitive than amino-terminal cross-linking telopeptide of type I collagen (NTx) and urinary pyridinolines, which were sensitive to anaerobic exercise. Whereas, the bone formation markers, bone alkaline phosphatase (BAP) and osteocalcin (OC) changed after 1 month and 2 months of an exercise programme, respectively. After 2 months, while BAP normalized, it was found to be sensitive to aerobic exercise and OC was found to be sensitive to anaerobic exercise. After prolonged training and competition, bone formation markers are found to change in sedentary subjects enrolled in a physical activity programme. Professional athletes show changes in bone formation markers depending on programme intensity, whereas bone resorption appears to stabilize. Crucial for long-term training, are the characteristics of exercise (e.g. weight-bearing, impact).

Bone metabolism markers in sports medicine

Bone mass can be viewed as the net product of two counteracting metabolic processes, bone formation and bone resorption, which allow the skeleton to carry out its principal functions: mechanical support of the body, calcium dynamic deposition and haemopoiesis. Besides radiological methods, several blood and urinary molecules have been identified as markers of bone metabolic activity for estimating the rates and direction of the biological activities governing bone turnover. The advantages for the use of bone metabolism markers are that they are potentially less dangerous than radiological determinations, are more sensitive to changes in bone metabolism than radiological methods and are easily collected and analysed. The disadvantages are that they have high biological variability. Physical exercise is a known source of bone turnover and is recommended for preventing osteoporosis and bone metabolism problems. There are numerous experiments on bone metabolism markers after acute exercise, but not after long-term training and during or after a whole competition season. Moreover, few studies on bone metabolism markers have evaluated their performance in elite and top-level athletes, who have a higher bone turnover than sedentary individuals. Despite discrepant results among studies, most have shown that short exercise is insufficient for modifying serum concentrations of bone metabolism markers. Marker variations are more evident after several hours or days after exercise, bone formation markers are more sensitive than bone resorption markers, and stimulation of osteoblast and/or osteoclast functions is exercise dependent but the response is not immediate. The response depends on the type of exercise; the markers seem to be less sensitive to resistance exercise and the intensity of exercise is not discriminate. Comparisons between trained subjects and untrained controls have demonstrated the influence of exercise on bone turnover. During training, carboxy-terminal collagen cross-links (CTx), a bone resorption marker, was shown to be less sensitive than amino-terminal cross-linking telopeptide of type I collagen (NTx) and urinary pyridinolines, which were sensitive to anaerobic exercise. Whereas, the bone formation markers, bone alkaline phosphatase (BAP) and osteocalcin (OC) changed after 1 month and 2 months of an exercise programme, respectively. After 2 months, while BAP normalized, it was found to be sensitive to aerobic exercise and OC was found to be sensitive to anaerobic exercise. After prolonged training and competition, bone formation markers are found to change in sedentary subjects enrolled in a physical activity programme. Professional athletes show changes in bone formation markers depending on programme intensity, whereas bone resorption appears to stabilize. Crucial for long-term training, are the characteristics of exercise (e.g. weight-bearing, impact).

Interpretation and application of bone turnover markers in children and adolescents

PURPOSE OF REVIEW

To assess recent research findings on various biochemical bone turnover markers and to assess their use in monitoring bone growth in children and adolescents.

RECENT FINDINGS

There are very few recent studies that investigate various serum and urine analytes that reflect bone formation and resorption to monitor bone health during longitudinal growth. In infants and young children, the measurement of bone markers in serum is suggested because of the practical difficulties associated with urine collection and by the circadian and intraindividual variation in urinary markers. During the prepubertal growth, bone turnover values are similar in age-matched boys and girls. The increase in different bone turnover markers coincides with the pubertal growth spurt. This starts later in boys and the increase in bone turnover markers also occurs later, is greater and lasts longer when compared with girls. Recent studies demonstrated that bone size increases and bone turnover decreases until mid-twenties.

SUMMARY

More than one bone formation and resorption marker should be measured to monitor longitudinal growth and bone mineral accrual, because sensitivities and predictive values of single markers are still poor. It is important to find new and more sensitive markers that could better characterize linear growth.

Is obesity protective for osteoporosis? Evaluation of bone mineral density in individuals with high body mass index

BACKGROUND

Obese individuals often present comorbidities while they appear protected against the development of osteoporosis. However, few and contradictory data are now available on skeletal modifications in obese patients. The aim of this study was to characterise bone mineral density (BMD) in overweight (BMI > 25 < 29.9) and obese (BMI > 30) patients.

METHODS

We selected 398 patients (291 women, 107 men, age 44.1 + 14.2 years, BMI 35.8 + 5.9 kg/m(2)) who underwent clinical examination, blood tests and examination of body composition. Subjects with chronic conditions or taking medications interfering with bone metabolism, hormonal and nutritional status and recent weight loss were excluded.

RESULTS

Interestingly, 37% (n = 146) of this population showed a significantly lower than expected lumbar BMD: 33% (n = 98) of women showed a T-score -1.84 +/- 0.71, and 45% (n = 48) of men showed a T-score -1.88 +/- 0.64. When the population was divided into subgroups based on different BMI, it was noted that overweight (BMI > 25 < 29.9) was neutral or protective for BMD, whereas obesity (BMI > 30) was associated with a low bone mass, compatible with a diagnosis of osteoporosis. No differences were observed in hormones and lipid profiles among subgroups.

CONCLUSIONS

Our results indicate that a subpopulation of obese patients has a significant low lumbar BMD than expected for age. Thus, a careful characterisation of skeletal metabolism might be useful in all obese individuals to avoid fragility fractures later in life.

Effects of diet-induced obesity and voluntary wheel running on bone properties in young male C57BL/6J mice

Both physical activity and body mass affect bone properties. In this study we examined how diet-induced obesity combined with voluntary physical activity affects bone properties. Forty 7-week-old male C57BL/6J mice were assigned to four groups evenly: control diet (C), control diet + running (CR), high-fat diet (HF, 60% energy from fat), and high-fat diet + running (HFR). After 21-week intervention, all mice were killed and the left femur was dissected for pQCT and mechanical measurements. Body mass increased 80% in HF and 62% in HFR, with increased epididymal fat pad weight and impaired insulin sensitivity. Except for total and trabecular volumetric bone mineral density (BMD), bone traits correlated positively with body mass, fat pad, leptin, and osteoprotegerin. Obesity induced by a high-fat diet resulted in increased femoral bone cross-sectional area, mineral content (BMC), polar moment of inertia, and mechanical parameters. Of the mice accessing the running wheel, those fed the control diet had thinner cortex and less total metaphyseal BMC and BMD, with enlarged metaphyseal marrow cavity, whereas mice fed the high-fat diet had significantly higher trabecular BMD and smaller marrow cavity. However, the runners had a weaker femoral neck as indicated by decreased maximum flexure load. These results suggest that voluntary running exercise affects bone properties in a site-specific manner and that there is a complex interaction between physical activity and obesity. Thus, both diet and exercise should be considered when optimizing the effects on body composition and bone, even though the underlying mechanisms remain partly unknown.

Comparison of glucose and lipid metabolism and bone mineralization in patients with growth hormone deficiency with and without long-term growth hormone replacement

The effects of long-term growth hormone (GH) substitution in pituitary-insufficient patients with GH deficiency (GHD-pats) on glucose and lipid metabolism and bone mineral density (BMD) have yet to be ascertained. We performed this cross-sectional study comparing GHD-pats with and without long-term GH substitution. We measured lipid parameters at baseline and glucose and insulin concentrations for 3 hours during oral glucose tolerance test in 52 GHD-pats (21 female and 31 male; median age, 51.5 years [27-82]). Twenty-two GHD-pats were on constant GH substitution (GH-Subs) for a median of 10 years (2-42 years). Thirty GHD-pats had not been substituted for at least 2 years (non-Subs). For analyses of beta-cell function, insulin resistance (IR), and sensitivity, homeostatic model assessment (HOMA)-beta , HOMA-IR, and insulin sensitivity index were used, respectively. Body composition and BMD were measured by dual-energy x-ray absorptiometry. Age and body mass index did not differ significantly between groups. Fasting glucose was significantly lower for GH-Subs than non-Subs (87 mg/dL [71-103] vs non-Subs 89 mg/dL [71-113], P < .05), whereas basal insulin did not differ significantly (10 muU/mL (4-42) vs non-Subs 10 microU/mL [4-63]). Glucose and insulin levels at 120 minutes as well as patients' area under the curve, C-peptide, hemoglobin A(1c), waist-hip ratio, HOMA-beta, HOMA-IR, insulin sensitivity index, lipid parameters, and BMD did not differ significantly; but total fat mass was significantly higher in non-Subs (37% [20%-52%] vs GH-sub 31% [13%-54%], P < .01). More non-Subs had abnormal glucose tolerance (19 [63%] vs GH-Subs 9 [41%]). Long-term GH substitution trends to beneficially influence fasting glucose and glucose tolerance, although differences are sparse. Growth hormone substitution alone does not seem to significantly impact on insulin sensitivity, lipid metabolism, and BMD in patients with pituitary insufficiency.

Role of chemerin/CMKLR1 signaling in adipogenesis and osteoblastogenesis of bone marrow stem cells

Maintenance of healthy bone mass requires a well-coordinated balance between the ongoing processes of bone formation and bone resorption. Bone-forming osteoblasts derive from resident adult stem cells within bone marrow called bone marrow stromal cells (BMSCs). These BMSCs are multipotent and also can give rise to adipocytes, which do not contribute directly to bone formation but may influence bone remodeling through the release of bioactive signaling molecules. Chemerin is a novel adipocyte-derived signaling molecule that promotes adipocyte differentiation. In this study we examined the role of chemerin and the cognate receptors CMKLR1 and CCRL2 as determinants of osteoblast and adipocyte differentiation of the preosteoblast 7F2 cell line and of primary BMSCs. Expression and secretion of chemerin increased dramatically with adipocyte differentiation of these cells. Functionally, knockdown of chemerin or CMKLR1 expression using RNA interference abrogated adipocyte differentiation, clonal expansion, and basal proliferation of BMSCs. In contrast, knockdown of either gene was associated with increased osteoblast marker gene expression and mineralization in response to osteoblastogenic stimuli. Forced expression of the adipogenic transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma) induced chemerin expression and partially rescued the loss of adipogenesis associated with chemerin or CMKLR1 knockdown in BMSCs. Taken together, these data support a novel role for chemerin/CMKLR1 signaling in regulating adipogenesis and osteoblastogenesis of bone marrow-derived precursor cells. These data reveal a potential role for this signaling pathway as a modulator of bone mass.

High bone mineral density is associated with high body mass index

SUMMARY

High BMD is an infrequent finding. In this retrospective cohort study of women 50 years and older, we documented a strong association between high BMD and high BMI.

INTRODUCTION

High bone mineral density (BMD) has been associated with genetic disorders and a variety of dietary, endocrine, metabolic, infectious and neoplastic diseases that in many cases warrant medical attention. Since body mass index (BMI) is closely correlated with BMD, we sought to explore the relationship between these two parameters in older women.

METHODS

We conducted a retrospective clinical cohort study of 16,500 women 50 years and older who underwent baseline BMD testing between May 1998 and October 2002. Mean T-scores and Z-scores, and the proportions of women with high BMD (T-score +2.5 or greater, Z-score +2.0 or greater), were assessed according to BMI category.

RESULTS

Higher BMI category was associated with higher mean T-scores and Z-scores at all sites (P < 0.001). The proportion of women with high BMD increased with each BMI category (P for trend <0.05). In women with a lumbar spine T-score of +2.5 or more, 43.5% were obese with BMI > 30 kg/m(2) (55.6% for the femoral neck and 73.1% for the total hip). For women with a lumbar spine Z-score of +2.0 or more, 37.2% were obese (42.0% for the femoral neck and 50.9% for the total hip). There was no evidence of a paradoxical increase in fracture rates in women with high BMD.

CONCLUSIONS

High BMD is closely associated with elevated BMI in women. This should be taken into consideration prior to initiating extensive investigations for rare pathologies.

The relation of femoral osteon geometry to age, sex, height and weight

As computational modeling becomes an increasingly common tool for probing the regulation of bone remodeling, the need for experimental data to refine and validate such models also grows. For example, van Oers et al. (R.F. van Oers, R. Ruimerman, B. van Rietbergen, P.A. Hilbers, R. Huiskes, Relating osteon diameter to strain. Bone 2008;43: 476-482.) recently described a mechanism by which osteon size may be regulated (inversely) by strain. Empirical data supporting this relation, particularly in humans, are sparse. Therefore, we sought to determine if there is a link between body weight (the only measure related to loading available for a cadaveric population) and osteon geometry in human bone. We hypothesized that after controlling for age, sex and height, weight would be inversely related to femoral osteon size (area, On.Ar; diameter, On.Dm). Secondarily we sought to describe the relation between osteon circularity (On.Cr) and these parameters. Osteons (n=12,690) were mapped within microradiographs of femoral mid-diaphyseal specimens (n=88; 45 male, 43 female; 17-97 yrs). Univariate analysis of covariance was conducted (n=87; 1 outlier) with sex as a fixed factor and height, weight and log-transformed age as covariates. Weight was negatively related to On.Ar and On.Dm (p=0.006 and p=0.004, respectively). Age was significantly related to osteon and, it was also significantly related to circularity (all p<0.001). This relation was negative for On.Ar and On.Dm and positive for On.Cr (increasing circularity with age). On.Ar and On.Dm were found to be significantly different between the sexes (p=0.021 and p=0.019, respectively), with females having smaller osteons. No relation between sex and On.Cr was detected (p=0.449). Height was not significantly related to any of the geometric parameters. Partial eta-squared values revealed that age accounted for the largest proportion (On.Ar: 28%, On.Dm: 18%, On.Cr: 30%), weight accounted for the second largest (On.Ar: 9%, On.Dm: 10%) and sex accounted for the smallest proportion (On.Ar: 6%, On.Dm: 7%) of the variance in geometry. While previous studies have reported relations between osteon size and sex/age, we believe that our findings are the first to demonstrate a link with weight. We believe that this negative relation with weight is most probably mechanical in nature; however, alternative (endocrine) links between bone and adipose tissue cannot be ruled out by our design.

Adipose tissue of control and ex-obese patients exhibit differences in blood vessel content and resident mesenchymal stem cell population

BACKGROUND

The normal function of white adipose tissue is disturbed in obesity. After weight loss that follows bariatric surgery, ex-obese patients undergo plastic surgery to remove residual tissues and it is not known whether their adipose tissue returns to its original state. The aim of this study was to compare the white adipose tissue composition of ex-obese with control patients with regard to blood vessels and resident mesenchymal stem cells (MSC).

METHODS

Quantification of blood vessels was performed on histological sections of adipose tissue stained with hematoxylin and eosin and for von Willebrand antigen. MSC were induced to the adipogenic and osteogenic lineages by specific inductive culture media. Expression of PPARgamma2 was analyzed by reverse transcription polymerase chain reaction.

RESULTS

Ex-obese adipose tissue showed a higher number (p = 0.0286) of small (107.3 +/- 22.0) and large (22.5 +/- 6.4) blood vessels, when compared to control patients (42.0 +/- 24.4 and 7.2 +/- 2.2, respectively) and they also occupied a larger area (control versus ex-obese, p = 0.0286). Adipose tissue MSC from both groups of patients expressed PPARgamma2 and were equally able to differentiate to the osteogenic lineage, but ex-obese MSC showed a higher adipogenic potential when induced in vitro (p < 0.05).

CONCLUSIONS

The higher number of adipose tissue blood vessels in ex-obese patients explains the excessive bleeding observed during their plastic surgery. The presence of more committed cells to the adipogenic lineage may favor the easy weight regain that occurs in ex-obese patients. These results show that, after extensive weight loss, adipose tissue cell composition was not totally restored.

Adipokines in the treatment of diabetes mellitus and obesity

BACKGROUND

The physiology of adipose tissue plays a main role in the pathogenesis of type 2 diabetes mellitus. The secretion of adipocyte-derived hormones, in either an autocrine or a paracrine manner, has been proposed as a relevant mechanism in this process. In this sense, the administration and regulation of hormones derived from adipose tissue arises as an attractive option for treating metabolic disorders.

OBJECTIVE

To review the current understanding of the implication of adipokines in the development of obesity and insulin resistance, as well as their potential use as therapeutic agents.

METHODOLOGY

Review of scientific literature.

CONCLUSIONS

This review describes the role of adipokines in generating insulin resistance and the chronic low-grade inflammatory profile accompanying visceral obesity.

Evaluation of bone disease in morbidly obese women after gastric bypass and risk factors implicated in bone loss

BACKGROUND

In patients undergoing gastric bypass, massive weight loss and impairment of calcium intake and absorption in the duodenum and proximal jejunum may increase the risk of bone mass loss and fractures. However, few data are available regarding the impact of this surgery on the skeleton. The aim of our study was to examine the skeletal changes in a cohort of morbidly obese Caucasian women during the first year after gastric bypass and to analyse the factors implicated in the development of bone loss.

METHODS

Sixty-two morbidly obese white women aged 45.3 +/- 8.9 years were studied. Anthropometric measurements, bone mineral density (BMD) screening using dual-energy X- ray absorptiometry and plasma determinations of calcium, phosphorus, parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH) D(3)] and insulin-like growth factor-I (IGF-I) were made prior to and 12 months after surgery.

RESULTS

A year after surgery, BMD significantly decreased at the femoral neck (10.2 +/- 5.7%) and at the lumbar spine (3.2 +/- 4.4%). In the follow-up, 16.1% of women had osteopenia at the femoral neck and 19.3% at the lumbar spine, and 1.6% developed osteoporosis at the lumbar spine. Patients with bone disease were significantly older; the percentage of women with menopause was greater in this group and had lower initial and final values of lean mass. However, no differences in body mass index, weight loss, fat mass, calcium, PTH, 25(OH) D(3) or IGF-I values were found between groups. In the logistic regression analysis, lean mass 12 months after surgery and menopause were found to be the main determinants of osteopenia after adjusting for age with odds ratios of 0.82 and 9.13, respectively.

CONCLUSIONS

There is a significant BMD loss at the femoral neck and lumbar spine a year after gastric bypass. Menopausal patients and those with greater lean mass loss are at greater risk and, consequently, should be closely followed up with periodic densitometries.

Strength training combined with plyometric jumps in adults: sex differences in fat-bone axis adaptations

Leptin and osteocalcin play a role in the regulation of the fat-bone axis and may be altered by exercise. To determine whether osteocalcin reduces fat mass in humans fed ad libitum and if there is a sex dimorphism in the serum osteocalcin and leptin responses to strength training, we studied 43 male (age 23.9 2.4 yr, mean +/- SD) and 23 female physical education students (age 23.2 +/- 2.7 yr). Subjects were randomly assigned to two groups: training (TG) and control (CG). TG followed a strength combined with plyometric jumps training program during 9 wk, whereas the CG did not train. Physical fitness, body composition (dual-energy X-ray absorptiometry), and serum concentrations of hormones were determined pre- and posttraining. In the whole group of subjects (pretraining), the serum concentration of osteocalcin was positively correlated (r = 0.29-0.42, P < 0.05) with whole body and regional bone mineral content, lean mass, dynamic strength, and serum-free testosterone concentration (r = 0.32). However, osteocalcin was negatively correlated with leptin concentration (r = -0.37), fat mass (r = -0.31), and the percent body fat (r = -0.44). Both sexes experienced similar relative improvements in performance, lean mass (+4-5%), and whole body (+0.78%) and lumbar spine bone mineral content (+1.2-2%) with training. Serum osteocalcin concentration was increased after training by 45 and 27% in men and women, respectively (P < 0.05). Fat mass was not altered by training. Vastus lateralis type II MHC composition at the start of the training program predicted 25% of the osteocalcin increase after training. Serum leptin concentration was reduced with training in women. In summary, while the relative effects of strength training plus plyometric jumps in performance, muscle hypertrophy, and osteogenesis are similar in men and women, serum leptin concentration is reduced only in women. The osteocalcin response to strength training is, in part, modulated by the muscle phenotype (MHC isoform composition). Despite the increase in osteocalcin, fat mass was not reduced.