Bone Mineral Mass Research Articles

Children and Adolescents with Severe Mental Illness Need Vitamin D Supplementation Regardless of Disease or Treatment

To protect against osteoporosis, keeping the vitamin D blood level (25[OH]D; VDBL) above 30 ng/mL is recommended. It is established that regular intake of vitamin D, calcium intake, and physical exercise contribute to maximizing bone mineral mass during childhood and adolescence. Recent articles suggest that patients with schizophrenia treated with antipsychotics have low VDBL and may have a higher risk of hip fractures in their later years than the general population. To evaluate whether adolescent psychiatric inpatient VDBL is lower than the 30-ng/mL optimal threshold and to document low-VDBL risk factors. We determined the VDBL of all consecutive inpatients from three adolescents units in 2009 (N = 136). Univariate analyses explored the influence on VDBL of (1) well-documented risk factors (e.g., age, gender, ethnic origin, body mass index, or season) and (2) suspected risk factors (e.g., disease type or antipsychotic treatment). All but six patients had a VDBL <30 ng/mL (mean [ ± SD]: 15.9 [ ± 8.4] ng/mL). VDBL was significantly lower for all patients during the first quarter of the year compared to the other three (all p < 0.01). VDBL was also lower for blacks/North Africans 12.8 (±7.0) than for Caucasians/Europeans 17.2 (±8.5): t = 2.62, p = 0.009. We found no differences between patients regarding disease category (K = 3.75, p = 0.154) or antipsychotic treatment (t = 0.127, df = 124, p = 0.89). VDBL in an adolescent population with severe mental illness is lower than current recommendations of optimal level for bone health regardless of treatment or disease type. Because adolescence is a period of bone construction and could represent a critical window of opportunity for maximizing bone mass, especially among patients with severe mental illness, we recommend vitamin D supplementation.

Pérdida de masa ósea en pacientes con cáncer de próstata sometidos a deprivación androgénica

Context treatment based on androgenic deprivation is one of the standard treatments that many prostate cancer patients receive. Moreover, its use is increasing due to a clear expansion of the indications of this therapy in patients with localized cancer. Summary of evidence in spite of being classically considered that it is well tolerated, androgenic deprivation has adverse effects. Of these, it is worth mentioning the loss of mineral bone mass, which can lead to osteoporosis and increase the risk of bone fracture. Some fractures may have serious consequences, as occurs with hip fractures. To make a diagnosis in this situation, there are useful procedures such as bone densitometry. Once diagnosed, the decrease in mineral bone mass can be managed with dietary recommendations, general changes in lifestyle, or with drugs such as denosumab. Conclusions following applicable recommendations, urologists must carefully monitor the bone health of patients with prostate cancer subjected to androgenic deprivation, in order to obtain an early diagnosis and to apply the appropriate general and/or therapeutic measures, if necessary.

Role of RANKL-RANK/osteoprotegerin molecular complex in bone remodeling and its immunopathologic implications

Bone remodeling is a cyclic and continuous physiological process, which ensures the conservation and renewal of the bone matrix. Osteosynthesis of the bone matrix is achieved by osteoblasts and coordinated within this complex machinery of bone remodeling with resorption of extracellular bone matrix performed by osteoclasts. The mismatch between the activities of osteoblasts and osteoclasts has immunopathologic implications associated with either a decrease or increase of bone mass mineral density. The balance of the trimolecular control factor complex composed of osteoprotegerin (OPG), RANKL (osteoprotegerin ligand) and RANK maintains physiologic bone remodeling. This trimolecular complex functions as receptors and ligands and belongs to the superfamily of tumor necrosis factor (TNF). This mini review highlights the complex interplay of the RANKL–RANK/OPG axis and their immunopathologic implications in clinical medicine.

Effect of a general school-based physical activity intervention on bone mineral content and density: A cluster-randomized controlled trial

BackgroundSpecific physical loading leads to enhanced bone development during childhood. A general physical activity program mimicking a real-life situation was successful at increasing general physical health in children. Yet, it is not clear whether it can equally increase bone mineral mass. We performed a cluster-randomized controlled trial in children of both gender and different pubertal stages to determine whether a school-based physical activity (PA) program during one school-year influences bone mineral content (BMC) and density (BMD), irrespective of gender. MethodsTwenty-eight 1st and 5th grade (6–7 and 11–12year-old) classes were cluster randomized to an intervention (INT, 16 classes, n=297) and control (CON; 12 classes, n=205) group. The intervention consisted of a multi-component PA intervention including daily physical education with at least 10min of jumping or strength training exercises of various intensities. Measurements included anthropometry, and BMC and BMD of total body, femoral neck, total hip and lumbar spine using dual-energy X-ray absorptiometry (DXA). PA was assessed by accelerometers and Tanner stages by questionnaires. Analyses were performed by a regression model adjusted for gender, baseline height and weight, baseline PA, post-intervention pubertal stage, baseline BMC, and cluster. Results275 (72%) of 380 children who initially agreed to have DXA measurements had also post-intervention DXA and PA data. Mean age of prepubertal and pubertal children at baseline was 8.7±2.1 and 11.1±0.6years, respectively. Compared to CON, children in INT showed statistically significant increases in BMC of total body, femoral neck, and lumbar spine by 5.5%, 5.4% and 4.7% (all p<0.05), respectively, and BMD of total body and lumbar spine by 8.4% and 7.3% (both p<0.01), respectively. There was no gender⁎group, but a pubertal stage⁎group interaction consistently favoring prepubertal children. ConclusionA general school-based PA intervention can increase bone health in elementary school children of both genders, particularly before puberty.

Recovery of bone strength in young pigs from an induced short-term dietary calcium deficit followed by a calcium replete diet

This study investigated whether the deficits in bone strength of pre-pubertal pigs, induced by short-term deficits in dietary calcium can be recovered if followed by a calcium-fortified diet. Young pigs were divided into two groups based on diet: a marginal Ca diet (70% of established Ca requirements) or an excess Ca diet (150% of established Ca requirements) for 4 weeks. Each group was then randomly sub-divided into two groups and fed diets with either marginal or excess dietary Ca for 6 weeks in a cross-over design, resulting in four treatment groups: H150–H150, H150–L70, L70–H150, and L70–L70. Animals were DXA scanned at 2-week intervals during the 10-week period to obtain whole body bone mineral content (BMC) and density (BMD). After animals were euthanized, right femurs were collected for this study. Traits such as bone mineral density, mass, volume, area moment of inertia (MI) and the section modulus (SM) were computed from computed tomography (CT) data and failure load was measured from four-point bending tests. DXA results showed significant reduction in BMC (61.6%) and BMD (37.5%) in the (L70–L70) group compared to the (H150–H150) group. DXA results additionally showed that deficiencies induced by the 4-week marginal Ca diet in the (L70–H150) group were not recovered with a subsequent excess Ca diet. While mechanical test results also showed significant reduction (75%) in strength in the L70–L70 group, compared to the H150–H150 group, they revealed no differences between the failure loads of the (L70–H150) group and the (H150–H150) group. Similar results were also found for bone mineral mass and volume, indicating that recovery from a short-term dietary Ca deficiency is possible at the pre-pubertal stage. Furthermore, bone mineral content and bone volume calculated from CT data correlated highly with failure load ( R 2 = 0.78 and 0.84, respectively), while density, MI and SM only showed weak-to-moderate correlations ( R 2 = 0.40–0.56), implying that bone mineral mass and volume calculated from CT data are good non-invasive surrogates for strength of growing bones.

Influence of long-term postmenopausal hormone-replacement therapy on estimated structural bone strength: A study in discordant monozygotic twins

Although postmenopausal hormone-replacement therapy (HRT) is known to prevent fractures, knowledge on the influence of long-term HRT on bone strength and its determinants other than areal bone mineral density is scarce. This study used a genetically controlled design with 24 monozygotic female twin pairs aged 54 to 72 years in which one cotwin was using HRT (mean duration 8 years) and the other had never used HRT. Estimated bone strength, cross-sectional area, volumetric bone mineral density, bone mineral mass, and cross-sectional density and mass distributions were assessed in the tibial shaft, distal tibia, and distal radius with peripheral computed tomography (pQCT). In the tibial shaft, HRT users had 9% [95% confidence interval (CI) 3%-15%] higher estimated bending strength than their nonusing cotwins. Larger cortical area and higher cortical bone mineral density accounted for this difference. The cortex was larger in the HRT users in the endocortical region. In the distal tibia, estimated compressive strength was 24% (95% CI 9%-40%) higher and in the distal radius 26% (95% CI 11%-41%) higher in the HRT users than in their nonusing cotwins owing to higher volumetric bone mineral density. No difference between users and nonusers was observed in total bone cross-sectional area in any measured bone site. The added mineral mass in the HRT users was distributed evenly within and between bone sites. In postmenopausal women, long-term HRT preserves estimated bone strength systemically by preventing bone mineral loss similarly in body weight-loaded and non-weight-loaded bone.

Primary antiphospholipid syndrome in premenopausal women: low vitamin D, high fat mass and maintained bone mineral mass

The aim of this study was to analyze vitamin D levels and their association with bone mineral density and body composition in primary antiphospholipid syndrome. For this cross-sectional study 23 premenopausal women with primary antiphospholipid syndrome (Sapporo criteria) and 23 age- and race-matched healthy controls were enrolled. Demographic, anthropometric, clinical and laboratorial data were collected using clinical interview and chart review. Serum 25-hydroxyvitamin D levels, parathormone, calcium and 24-hour urinary calcium were evaluated in all subjects. Bone mineral density and body composition were studied by dual X-ray absorptiometry. The mean age of patients and controls was 33 years. Weight (75.61 [20.73] vs. 63.14 [7.34] kg, p = 0.009), body mass index (29.57 [7.17] vs. 25.35 [3.37] kg, p = 0.014) and caloric ingestion (2493 [1005.6] vs. 1990 [384.1] kcal/day, p = 0.03) were higher in PAPS than controls. All PAPS were under oral anticoagulant with INR within therapeutic range. Interestingly, biochemical bone parameters revealed lower levels of 25-hydroxyvitamin D [21.64 (11.26) vs. 28.59 (10.67) mg/dl, p = 0.039], serum calcium [9.04 (0.46) vs. 9.3 (0.46) mg/dl, p = 0.013] and 24-hour urinary calcium [106.55 (83.71) vs. 172.92 (119.05) mg/d, p = 0.027] in patients than in controls. Supporting these findings, parathormone levels were higher in primary antiphospholipid syndrome than in controls [64.82 (37.83) vs. 44.53 (19.62) pg/ml, p = 0.028]. The analysis of osteoporosis risk factors revealed that the two groups were comparable (p > 0.05). Lumbar spine, femoral neck, total femur and whole body bone mineral density were similar in both groups (p > 0.05). Higher fat mass [28.51 (12.93) vs. 20.01 (4.68) kg, p = 0.005] and higher percentage of fat [36.08 (7.37) vs. 31.23 (4.64)%, p = 0.010] were observed in PAPS in comparison with controls; although no difference was seen regarding lean mass. In summary, low vitamin D in primary antiphospholipid syndrome could be secondary to higher weight and fat mass herein observed most likely due to adipocyte sequestration. This weight gain may also justify the maintenance of bone mineral density even with altered biochemical bone parameters.

Impact of protein intake and physical activity on bone mineral mass and size of weight bearing sites before puberty and 7.8 Yrs later: a longitudinal study in healthy boys

Impact of protein intake and physical activity on bone mineral mass and size of weight bearing sites before puberty and 7.8 Yrs later: a longitudinal study in healthy boys

Bone mineral density and body composition in adolescents with failure to thrive.

ObjectiveTo evaluate bone mineral mass in adolescents with failure to thrive in relation to body composition.MethodsA case control study involving 126 adolescents (15 to 19 years), in final puberty maturation being 76 eutrophic and 50 with failure to thrive (genetic or constitutional delay of growth), of matching ages, gender and pubertal maturation. The weight, height and calculated Z score for height/age and body mass index; bone mineral content, bone mineral density and adjusted bone mineral density were established for total body, lower back and femur; total fat-free mass and height-adjusted fat-free mass index, total fat mass and height-adjusted. The statistical analyses were performed using the Student's t-test (weight, height and body composition); Mann-Whitney test (bone mass) and multiple linear regression (bone mass determinants).Resultsweight, height and height/age Z-score were significantly higher among eutrophic subjects. Both groups did not show statistically significant differences for fat mass, percentage of fat mass, total fat mass height adjusted and fat-free mass index height sadjusted. However, total free fat maass was smaller for the failure to thrive group.ConclusionsThere was no statistically significant difference for bone mass measurements among adolescents with failure to thrive; however, the factors that determine bone mass formation should be better studied due to the positive correlation with free fat mass detected in these individuals.

Comparing and contrasting the effects of strontium ranelate and other osteoporosis drugs on microarchitecture

Altered bone microstructure is a major component of osteoporosis and bone fragility. Whilst an important standard by which to diagnose and make treatment decisions for osteoporosis, the evaluation of bone mineral mass by dual-energy X-ray absorptiometry (DXA) at spine or hip is not sufficient for understanding the complex nature of bone microstructure nor to evaluate specific treatment effects on cancellous and cortical bone. Various alternatives to DXA have been developed, enabling the measurement of bone geometry and/or microarchitecture and/or bone strength including hip strength analysis, peripheral and central QCT, 3D analyses of iliac crest bone biopsies, and more recently HR-pQCT, which allows longitudinal assessment of bone microstructure at the distal radius and tibia. The efficacy of treatments for osteoporosis can be evaluated using these techniques. A true improvement of bone microstructure above baseline has not been demonstrated with anti-resorptive treatments; however, they may prevent the decay of cancellous bone and, potentially, cortical thinning. Anabolic agents such as parathyroid hormone (PTH) increase cancellous bone volume and cortical thickness; however, the improvement of cortical bone strength by PTH may be limited by an increase in cortical porosity. Strontium ranelate has been shown to improve not only the trabecular network but also cortical thickness, contributing to its anti-fracture efficacy at vertebral, non-vertebral, and hip sites.

The Co-effect of Cordyceps sinensis and Strontium on Osteoporosis in Ovariectomized Osteopenic Rats

The co-effect of Cordyceps sinensi (CS; caterpillar fungus) and strontium on ovariectomized osteopenic rats was studied in this paper. After the rats were treated orally with CS, strontium (SR), and CS rich in strontium (CSS), respectively, the urine calcium, plasma calcium, plasma phosphorus, bone mineral content, mechanical testing, and the mass of uterus, thymus, and body were examined. Both CSS and SR have a positive effect on mechanical strength and mineral content of ovariectomized osteopenic rats. However, femoral neck strength in the CSS-treated group was higher than those in the SR-treated groups. CSS and SR significantly decreased urinary calcium excretion and plasma total calcium and inorganic phosphate concentrations. On the contrary, CS and CSS significantly increased weights of atrophic uteri and weights of body and also decreased the thymus mass in animals, whereas SR did not exhibit any such effects. Our experiments have demonstrated that CSS possess a preferable effect against the decrease of bone strength and bone mineral mass caused by osteoporosis. It was caused by the co-effect of CS and strontium. The mechanism of it includes decreases bone resorption, increases bone formation, increases in body weight, and enhances 17β-estradiol-producing as well as enhancing the immune functions in animals. The data provide an important proof of concept that CSS might be a new potential therapy for the management of postmenopausal osteoporosis in humans.

The effects of loading and estrogen on rat bone growth

This study evaluated the contributions of locomotive loading and estrogen to the development of diaphysis of rat femur. A randomized 2x2 study design was used. Altogether, 70 female Sprague-Dawley rats were used, of which 10 were euthanized at entry. Of the remaining rats, 16 served as controls, and the rest, 44, underwent a unilateral sciatic neurectomy. The effect of estrogen was removed by ovariectomizing one-half of the neurectomized rats. After 27 wk, the animals were euthanized, and the femora were excised. Irrespective of loading or estrogen, the femur length and mineral mass increased by 142 and 687%, respectively. Axial growth was not modulated either by locomotive loading or estrogen, but the loading resulted in direction-specific changes in the cross-sectional geometry. The estrogen-related gains were evident on the endocortical surface, while the loading-related gains occurred on the periosteal surface. The loading and estrogen were significantly associated with increased bone strength (21 and 15%, respectively) in the mediolateral direction, but not in the anteroposterior direction. Axial growth and accrual of bone mineral mass of the rat femur are largely independent of locomotive loading or estrogen, whereas these factors specifically account for the femur function, as either a mechanical lever or a mineral reservoir for reproduction, respectively.

Obese canine skeletal muscle transcriptome exhibits altered inflammatory signaling

Obesity induces changes in skeletal muscle that lead to insulin resistance and metabolic dysfunction. The purpose of this study was to characterize the skeletal muscle transcriptome of lean and obese dogs after 24 wk of diet‐induced obesity. Intact female beagles were fed a commercially available high‐fat diet and randomized to either ad libitum feeding (n=5) or weight maintenance (n=4). Latissimus dorsi muscle and blood samples were collected and body composition was measured at baseline and at 24 wk. The skeletal muscle transcriptome of lean and obese dogs, at 24 wk, were assessed using Affymetrix Canine 2.0 microarrays and analyzed using the Limma package. Obese dogs had increased (P≤0.05) BW, body fat mass, bone mineral mass, and blood leptin and insulin concentrations, but lean mass and blood NEFA, triglycerides, glucose, and adiponectin concentrations were unchanged. 77 gene transcripts were differentially expressed in obese dogs. Functional classification of 55 annotated gene transcripts revealed differential regulation of cell signaling, transport, growth, and transcription. The obese state had decreased expression of anti‐inflammatory gene transcripts (SOCS2, CISH) and increased expression of pro‐inflammatory gene transcripts (STAT2, FLT1, TPST1). These results indicate that skeletal muscle of obese dogs has increased inflammation.Funding: Illinois CFAR # CF071‐003‐SEN

Effects of Intravenous Pamidronate on Renal Function, Bone Mineral Metabolism and Bone Mass in Patients With Severe Osteoporosis

IntroductionTo analyze the effects of intravenous pamidronate (APD) on bone remodelling, bone mineral density (BMD), fractures and bone mineral metabolism parameters, and the rate of adverse events, with special attention to renal function, in patients with osteoporosis with intolerance and/or any contraindication to oral bisphosphonates. MethodsWe analyzed prospectively 17 osteoporotic patients (age, 66.8±9.4years): 65% women, 82% with prevalent vertebral fractures. All patients received APD therapy (30mg intravenously every 3months) and were followed up for 1year. We analyzed serum amino-terminal propeptide of type I procollagen and urinary N-terminal cross-linked telopeptide of type I collagen (as markers of bone turnover), serum calcium, phosphate, parathormone, 25OH-vitamin D, creatinine, and the creatinine clearance: at baseline, 1week after starting APD treatment, and thereafter for every 3months (before infusion) during 1year. We also analyzed lumbar and femoral BMD at baseline and after 1year, the incidence of new fractures, and the treatment-related adverse events. ResultsOne week after starting APD treatment, a significant decrease of N-terminal cross-linked telopeptide of type I collagen (32%) (P<0.05) and an increase of parathormone values (72%) (P<0.01) were observed, without significant differences found thereafter. No significant differences were observed in BMD evolution and in the other parameters analyzed throughout the study, nor in impairment of renal function. Sixty-four percent of patients suffered new skeletal fractures, 41% of patients showed flu-like syndrome after APD infusion, and 1 patient was withdrawn from treatment because of adverse events. ConclusionsPatients with severe osteoporosis receiving APD infusions had a high rate of fractures without significant changes in bone mass or in bone markers; nevertheless, such a therapeutic regimen showed a good renal safety profile, suggesting that APD at this dosage is safe but ineffective for treating severe osteoporosis.

Avaliação de centrifugado osteogênico de medula óssea na consolidação de fratura em coelhos

OBJETIVO: Avaliar a eficácia de um centrifugado osteogênico de medula óssea em estimular a consolidação de osteotomias da fíbula em coelhos. MÉTODOS: Foram utilizados dez coelhos machos adultos da raça Nova Zelândia albino. Realizou-se uma osteotomia transversa médio-diafisária da fíbula direita, seguida da adição local de uma esponja de colágeno absorvível embebida em um centrifugado osteogênico, obtido pela centrifugação de aspirado de medula óssea do osso ilíaco ipsilateral. A fíbula esquerda foi utilizada como controle, sendo feita a mesma osteotomia, porém neste caso adicionando-se somente a esponja de colágeno absorvível. Após quatro semanas os animais foram sacrificados para estudo dos calos ósseos formados. Os critérios de avaliação foram a mensuração da densidade mineral utilizando-se a densitometria óssea com DEXA, do volume do calo com tomografia computadorizada multi-slice e dos tecidos formados por meio de histomorfometria. RESULTADOS: A utilização do centrifugado osteogênico resultou em um aumento médio na densidade mineral óssea dos calos de 40,3% e da quantidade relativa de tecido ósseo de 9,4%, sem aumento significativo nas quantidades relativas de cartilagem ou fibrose nem no volume do calo ósseo. CONCLUSÃO: A administração do centrifugado osteogênico de medula óssea utilizado neste estudo favoreceu a consolidação óssea de osteotomias experimentais em coelhos.

Body composition at high altitude: a randomized placebo-controlled trial of dietary carbohydrate supplementation

BackgroundBody mass loss is inevitable with chronic hypoxic exposure. However, the exact body-composition changes, their causes, and possible treatments remain unknown. ObjectiveThe objective was to investigate body composition during a high-altitude expedition by using non–empirically derived methods, experimentally manipulating energy intake, and investigating the influence of initial body composition. DesignForty-one participants completed a 21-d expedition in the Himalayas. Energy intake was manipulated with a double-blind, placebo-controlled, randomized trial of carbohydrate energy supplementation. Body composition was assessed before and after the expedition by using a 4-component model including fat mass, total body water, bone mineral mass, and residual mass (principally protein and glycogen). Data were analyzed by repeated-measures analysis of variance. ResultsParticipants allocated to receive carbohydrate were given an additional 15,058 ± 6211 kcal over the 21-d expedition (>6 kcal · kg−1 · d−1). Nevertheless, the functionally important residual mass decreased in both groups by 6% (main effect of time: P = 0.021), with no effect of allocation (interaction effect: P = 0.116). Similar decreases were observed for fat mass (11%) and total body water (3%), which were also unabated by allocation. Furthermore, high initial fat mass (by median split) did not preserve residual mass (high-fat compared with low-fat participants: residual loss = 5% compared with 8%; P = 0.990). ConclusionsHigh-altitude exposure decreased body mass, including the functionally important residual component. These losses were not abated by increasing energy intake or an initially high fat mass. Factors other than negative energy balance must contribute to body-composition changes with chronic hypoxia. This trial was registered at clinicaltrials.gov as NCT00731510.

Localization of Phosphorylated Serine, Osteopontin, and Bone Sialoprotein on Bone Fracture Surfaces

Bone mineral density or bone mass alone cannot reliably predict fracture risk in patients. It is generally accepted that bone quality, including the properties of the organic matrix of bone, should also be considered. Collagen type I accounts for about 90% of this organic matrix. The other 10% are accounted for by various proteins and proteoglycans usually summarized by the term noncollagenous proteins (NCPs). These NCPs have a large influence on the nanoscale organization of bone. In addition, some NCPs have intriguing properties that could strongly influence bone matrix material properties; they can form self-healing networks based on ion-mediated bonds. Such behavior was also reported for trabecular bone fracture surfaces, rejoined after cleavage. To obtain proof that this behavior of bone is due to NCPs, an immunohistochemical approach was chosen for the work presented in this communication. Antibodies for phosphoserine, which is abundant in many NCPs but not in collagen type I, as well as antibodies for osteopontin and bone sialoprotein, were used on human trabecular bone fracture surfaces and microfractured trabeculae. Signals were detected using secondary gold-labeled antibodies and backscattered scanning electron microscopy. We found homogenous NCP coverage of fracture surfaces and elevated signals on bridging ligaments. Osteopontin and bone sialoprotein were detected in localized patches. Overall, this work suggests that the self-healing effect of trabecluar bone fracture surfaces, rejoined after cleavage, can be explained by the presence of NCPs. In addition, we conclude that NCPs also constitute the interface that is disrupted when bone fails, attributing them high importance for bone matrix material properties and fracture risk.

Dietary Protein, Weight Loss, and Weight Maintenance

The role of dietary protein in weight loss and weight maintenance encompasses influences on crucial targets for body weight regulation, namely satiety, thermogenesis, energy efficiency, and body composition. Protein-induced satiety may be mainly due to oxidation of amino acids fed in excess, especially in diets with "incomplete" proteins. Protein-induced energy expenditure may be due to protein and urea synthesis and to gluconeogenesis; "complete" proteins having all essential amino acids show larger increases in energy expenditure than do lower-quality proteins. With respect to adverse effects, no protein-induced effects are observed on net bone balance or on calcium balance in young adults and elderly persons. Dietary protein even increases bone mineral mass and reduces incidence of osteoporotic fracture. During weight loss, nitrogen intake positively affects calcium balance and consequent preservation of bone mineral content. Sulphur-containing amino acids cause a blood pressure-raising effect by loss of nephron mass. Subjects with obesity, metabolic syndrome, and type 2 diabetes are particularly susceptible groups. This review provides an overview of how sustaining absolute protein intake affects metabolic targets for weight loss and weight maintenance during negative energy balance, i.e., sustaining satiety and energy expenditure and sparing fat-free mass, resulting in energy inefficiency. However, the long-term relationship between net protein synthesis and sparing fat-free mass remains to be elucidated.

Reduced muscle mass and bone size in pediatric patients with inflammatory bowel disease

Decreased bone mineral density has been reported in children with inflammatory bowel disease (IBD). We used peripheral quantitative computed tomography (pQCT) to assess bone mineralization, geometry, and muscle cross-sectional area (CSA) in pediatric IBD. In a cross-sectional study, pQCT of the forearm was applied in 143 IBD patients (mean age 13.9 +/- 3.5 years); 29% were newly diagnosed, 98 had Crohn's disease, and 45 had ulcerative colitis. Auxological data, cumulative glucocorticoid dose, disease activity indices, laboratory markers for inflammation, and bone metabolism were related to the results of pQCT. Patients were compromised in height (-0.82 +/- 1.1 SD), weight (-0.77 +/- 1.0 SD), muscle mass (-1.12 +/- 1.0 SD), and total bone cross-sectional area (-0.79 +/- 1.0 SD) compared to age- and sex-matched healthy controls (z-scores). In newly diagnosed patients, the ratio of bone mineral mass per muscle CSA was higher than in those with longer disease duration (1.00 versus 0.30, P = 0.007). Serum albumin level and disease activity correlated with muscle mass, accounting for 41.0% of variability in muscle mass (P < 0.01). The trabecular bone mineral density z-score was on average at the lower normal level (-0.40 +/- 1.3 SD, P < 0.05). Reduced bone geometry was explained only in part by reduced height. Bone disease in children with IBD seems to be secondary to muscle wasting, which is already present at diagnosis. With longer disease duration, bone adapts to the lower muscle CSA. Serum albumin concentration is a good marker for muscle wasting and abnormal bone development.

Effects of Natural Phenolic Acids on the Skeletal System of Ovariectomized Rats

Recent reports indicate the possibility of antiresorptive and/or bone formation increasing activity of natural phenolic acids, commonly present in plants which are normally consumed in the diet. The effects of 4 natural phenolic acids (ferulic, caffeic, P-coumaric or chlorogenic, 10 mg/kg P. O. daily for 4 weeks) on the skeletal system of ovariectomized (estrogen-deficient) rats were investigated. Bone mass, mineral and calcium content, macrometric and histomorphometric parameters, and mechanical properties were examined. Phenolic acids differentially affected the skeletal system of rats with osteoporotic changes induced by the ovariectomy. Caffeic acid decreased bone mass, whereas P-coumaric acid increased the bone mass/body mass ratio and bone mineral mass/body mass ratio in the long bones, in comparison with the ovariectomized control rats. The phenolic acids improved some bone histomorphometric parameters, impaired by estrogen deficiency. However, they did not increase the ratio of bone mineral mass to bone mass, decreased by estrogen deficiency, and did not significantly affect bone mechanical properties. In conclusion, different natural phenolic acids exert differential effects on the skeletal system of ovariectomized rats, both favourable and deleterious.