Vitamin D and its role in skeletal muscle

Obesity attenuates serum 25-hydroxyvitamin D response to cholecalciferol therapy in critically ill patients

OBJECTIVES

The presence of obesity may confound cholecalciferol dosing in vitamin D-deficient patients owing to potentially decreased bioavailability. The aim of this retrospective study was to evaluate cholecalciferol therapy in vitamin D-deficient, critically ill trauma patients with and without obesity.

METHODS

Adult patients with severe traumatic injuries who had a serum 25-hydroxyvitamin D (25-OH vit D) <50nmol/L were prescribed 10 000 IU of liquid cholecalciferol daily. Efficacy was defined as achievement of a 25-OH vit D of 75 to 200nmol/L. Safety was evaluated by the presence of hypercalcemia (serum ionized calcium >1.32 mmol/L). Fifty-three patients (18 obese, 35 non-obese) were identified for study.

RESULTS

Despite similar baseline concentrations (36 ± 7 versus 37 ± 7 nmol/L; P = NS), 25-OH vit D response was attenuated for those with obesity after 1 and 2 wk of cholecalciferol therapy (51 ± 18 versus 66 ± 27nmol/L, P < 0.01; 68 ± 19 versus 92 ± 25nmol/L, P < 0.01, respectively). Patients with obesity also tended to experience less hypercalcemia (22% versus 49% of patients, respectively) post-cholecalciferol therapy.

CONCLUSION

Obesity alters the response to cholecalciferol therapy in critically ill patients with severe traumatic injuries.

Potential Cellular and Biochemical Mechanisms of Exercise and Physical Activity on the Ageing Process

Exercise in young adults has been consistently shown to improve various aspects of physiological and psychological health but we are now realising the potential benefits of exercise with advancing age. Specifically, exercise improves cardiovascular, musculoskeletal, and metabolic health through reductions in oxidative stress, chronic low-grade inflammation and modulating cellular processes within a variety of tissues. In this this chapter we will discuss the effects of acute and chronic exercise on these processes and conditions in an ageing population, and how physical activity affects our vasculature, skeletal muscle function, our immune system, and cardiometabolic risk in older adults.

Cholecalciferol in ethanol-preferring rats muscle fibers increases the number and area of type II fibers

The chronic use of ethanol causes neuropathy and atrophy of type II fibers and promotes vitamin D decrease. This study evaluated cholecalciferol effects on the deep fibular nerve and extensor digitorum longus (EDL) muscle using an UChB ethanol-preferring rats model. Blood analyses were carried out to measure levels of 25-hydroxycholecalciferol (25(OH)D), calcium (Ca²⁺), Phosphorus (P), and parathyroid hormone (PTH). It was used EDL muscle to evaluate oxidative stress. The deep fibular nerve and EDL muscle were used for morphologic and morphometric assessment. 25(OH)D plasma levels were higher in the supplemented group and no alterations were observed in other parameters including the oxidative stress evaluation. The G ratio remained constant which indicates nervous conduction normality. Cholecalciferol supplementation promoted an increase in the number and area of type II fibers and a decrease in the area of type I fibers. In the studied model, there was neither alcoholic myopathy nor neuropathy. The EDL muscle glycolytic patterns in the high-drinker UChB rats may be associated with the differential effects of cholecalciferol on metabolism and protein synthesis in skeletal muscle.

Serum 25-Hydroxyvitamin D and Intact Parathyroid Hormone Influence Muscle Outcomes in Children and Adolescents

Increases in 25-hydroxyvitamin D concentrations are shown to improve strength in adults; however, data in pediatric populations are scant and equivocal. In this ancillary study of a larger-scale, multi-sited, double-blind, randomized, placebo-controlled vitamin D intervention in US children and adolescents, we examined the associations between changes in vitamin D metabolites and changes in muscle mass, strength, and composition after 12 weeks of vitamin D3 supplementation. Healthy male and female, black and white children and adolescents between the ages of 9 and 13 years from two US states (Georgia 34°N and Indiana 40°N) were enrolled in the study and randomly assigned to receive an oral vitamin D3 dose of 0, 400, 1000, 2000, or 4000 IU/d for 12 weeks between the winter months of 2009 to 2011 (N = 324). Analyses of covariance, partial correlations, and regression analyses of baseline and 12-week changes (post-baseline) in vitamin D metabolites (serum 25(OH)D, 1,25(OH)2 D, intact parathyroid hormone [iPTH]), and outcomes of muscle mass, strength, and composition (total body fat-free soft tissue [FFST], handgrip strength, forearm and calf muscle cross-sectional area [MCSA], muscle density, and intermuscular adipose tissue [IMAT]) were assessed. Serum 25(OH)D and 1,25(OH)2 D, but not iPTH, increased over time, as did fat mass, FFST, forearm and calf MCSA, forearm IMAT, and handgrip strength (p < 0.05). Vitamin D metabolites were not associated with muscle strength at baseline nor after the 12-week intervention. Changes in serum 25(OH)D correlated with decreases in forearm IMAT, whereas changes in serum iPTH predicted increases in forearm and calf MCSA and IMAT (p < 0.05). Overall, increases in 25(OH)D did not influence muscle mass or strength in vitamin D-sufficient children and adolescents; however, the role of iPTH on muscle composition in this population is unknown and warrants further investigation. © 2018 American Society for Bone and Mineral Research.

Vitamin D Attenuates FOXO1-Target Atrophy Gene Expression in C2C12 Muscle Cells

Vitamin D is known to be effective for the prevention of muscle atrophy, such as age-related sarcopenia. However, vitamin D action in skeletal muscle tissue and muscle cells is largely unknown. We previously found that a transcription factor, FOXO1 gene expression, was induced in various muscle atrophy conditions causing muscle atrophy by upregulating atrophy-related genes, including atrogin 1 (ubiquitin ligase) and cathepsin L (lysosomal proteinase). In this study, we found that vitamin D inhibited FOXO1-mediated transcriptional activity in a reporter gene assay. Moreover, vitamin D suppressed the glucocorticoid-induced gene expression of atrogin 1 and cathepsin L in C2C12 myoblasts. Thus, vitamin D may prevent muscle atrophy via the FOXO1-mediated pathway in muscle cells.

Influence of serum 25-hydroxyvitamin D levels, fat-free mass, and fat mass on bone density, geometry and strength, in healthy young and elderly adults

PURPOSE

The association between serum 25-hydroxyvitamin D (25-OHD) levels and cortical/trabecular bone parameters has been explored in the elderly, but less so in younger adults; body composition may also influence bone parameters across the life span. We aimed to investigate, with peripheral quantitative computerized tomography (pQCT), the relationship between serum 25-OHD levels and bone geometry and strength and, at the same time, to explore the influence of fat mass and fat-free mass on bone parameters, for the tibia and radius, in healthy young and elderly adults.

METHODS

The study involved 149 healthy adults grouped by age: 65 were under 65 years old, and 84 were older. All participants were assessed in terms of: clinical history; serum 25-OHD levels; fat-free mass (FFM) and fat mass (FM), measured with DXA; total and cortical bone cross-sectional area (CSA, CSAc), and trabecular and cortical bone mineral density (BMDt, BMDc); and fracture load x and y for the tibia and radius, measured with pQCT.

RESULTS

In the younger group, the association between 25-OHD levels and bone parameters did not remain as significant for any parameters after multivariate adjustment. In the elderly, 25-OHD correlated with CSAc (partial R² = 0.33), fracture load x (partial R² = 0.54), and fracture load y (partial R² = 0.46) for the radius, and marginally with BMDt (partial R² = 0.09; B-H adjusted p < 0.05 for all) for the tibia. FFM correlated with all bone parameters in both age groups. In the elderly group alone, FM correlated with BMDt at the tibia (r = 0.25, p < 0.05), with CSA at both sites (radius r = -0.25, p < 0.05; tibia r = -0.32, p < 0.001), and with fracture load y on the radius (r = -0.22, p < 0.05).

CONCLUSION

While serum 25-OHD levels correlated only weakly with bone parameters in younger adults, a significant relationship was observed for elderly people. Fat-free mass showed positive simple correlation with pQCT-derived bone parameters in both age groups except with BMDc in the younger group. Further longitudinal studies are needed to clarify these relationships.

Can vitamin D deficiency influence muscle performance in postmenopausal women? A multicenter retrospective study

BACKGROUND

The presence of the vitamin D receptor (VDR) has been recently demonstrated in human muscle supporting the theory of a role of vitamin D in the proliferation and differentiation of muscle cells. So far only few studies investigated the association between vitamin D and muscle performance in postmenopausal women.

AIM

To define the functional impact of vitamin D deficiency.

DESIGN

Multicenter retrospective study.

SETTING

Five Italian outpatient services of Physical and Rehabilitation Medicine (PRM).

POPULATION

Postmenopausal women.

METHODS

We divided the population in two groups based on the threshold of 30 ng/mL as cut-off to define sufficient and insufficient serum levels of 25-hydroxyvitamin D3 [25(OH)D3]. Outcome measures were: appendicular lean mass (ALM); ALM-to-BMI ratio (ALMBMI); total fat mass (FM); visceral adipose tissue (VAT); Hand Grip Strength (HGS); Knee Isometric Extension Strength (KES); Short Physical Performance Battery (SPPB); 4-meter gait speed (4MGS).

RESULTS

We analyzed the data records of 401 postmenopausal women (mean age 66.93±8.47 years): 203 with hypovitaminosis D (mean age 66.81±8.11 years) and 198 with normal levels of 25(OH)D3 (mean age 67.04±8.84 years). The analysis showed a significant difference between the two groups in terms of: ALMBMI (0.002), FM (P<0.001), VAT mass (0.010), VAT volume (P=0.006), HGS (P<0.001), KES (P<0.001), SPPB score (P<0.001), percentage of people with a 4MGS≤0.8 m/s (P<0.001). Furthermore, there were significant correlations (P<0.001) between serum levels of 25(OH)D3 and HGS (r=0.323), KES (r=0.510), and SPPB sit to stand (r=-0.362) and walking sub-scores (r=-0.312).

CONCLUSIONS

This multicenter study demonstrated that postmenopausal women with vitamin D deficiency had a significant reduction of appendicular muscle strength and physical performance.

CLINICAL REHABILITATION IMPACT

This study reported the frequency of hypovitaminosis D in postmenopausal women and its influence on the reduction of muscle mass, strength, and physical performance in a typical population referring to the physiatrist for musculoskeletal disorders.

Association Between Preoperative Vitamin D Status and Short-Term Physical Performance after Total Hip Arthroplasty: A Prospective Study

BACKGROUND

Insufficient serum vitamin D concentrations (50-75 nmol/L) are prevalent in 40-65% of patients who require total hip arthroplasty (THA). This could impair physical recovery after surgery. This study investigated the association between preoperative vitamin D status and physical performance after THA. Additionally, postoperative changes in vitamin D concentrations were measured.

METHODS

We included 87 patients scheduled for elective THA and aged ≥65 years. Three groups were recruited: patients classified as vitamin D deficient (< 50 nmol/L, n = 23), insufficient (50-75 nmol/L, n = 32), or sufficient (> 75 nmol/L, n = 32). Serum 25-hydroxyvitamin D3 (25[OH]D3) concentration and physical performance were measured perioperatively. Linear mixed models were used to examine differences between groups.

RESULTS

Change in physical performance over time was not affected by preoperative vitamin D status. In contrast, for physical activity, both vitamin D (p = 0.021) and time (p < 0.001) effect was seen: from 80.2 ± 25.8 to 58.1 ± 17.8 min/day in the deficient group, 143.7 ± 19.8 to 92.9 ± 11.5 min/day in the insufficient group, and 108.1 ± 20.9 to 62.3 ± 12.9 min/day in the sufficient group. The Chair Stand Test, Timed Up and Go test, and 10-Meter Walking Test also improved significantly over time, but independent of vitamin D status. An increase in 25(OH)D3 concentration 6 weeks postoperatively was correlated with improved hip function (Pearson's r = -0.471, p = 0.018). Overall, serum 25(OH)D3 declined with 32% one day after surgery (p < 0.001), to nearly return to baseline values 6 weeks later in all groups.

CONCLUSION

Vitamin D status did not appear to affect physical recovery after THA. The drop in vitamin D after surgery deserves further investigation, but could possibly be explained by hemodilution.

Clinical nutrition and physical rehabilitation in a long-term care setting: preliminary observations in sarcopenic older patients

BACKGROUND

Sarcopenia could have a negative prognostic impact in long-term care residents, which are characterized by multiple comorbidities and a high level of dependence. However, there is limited evidence on its prevalence and management in this healthcare setting.

METHODS

All residents living in a long-term care institution were screened for the presence of sarcopenia. Sarcopenic patients in whom functional status could be assessed were included, based on the Tinetti scale (TS) score, in two parallel single-arm trials and received a specific nutritional supplement for muscle mass recovery in combination (TS ≥ 10) or not (TS < 10) with a supervised physical exercise rehabilitation program for 12 months. The nutritional supplement was administered twice daily for the first 6 months; none for 3 months and again twice daily for the last 3 months.

RESULTS

We screened 95 residents and 81 had low skeletal muscle mass (SMM) according to bioimpedance. Thirty-nine residents were included in the intervention phase due to sarcopenia. At 6 months, patients receiving nutritional support alone (n = 17) showed a significant improvement in body weight (P = 0.009) and composition with an increase in SMM (from 15.3 ± 4.1 to 17.0 ± 5.1 kg, P = 0.013) and SMM index (SMI; from 6.24 ± 1.07 to 6.91 ± 1.54 kg/m², P = 0.013), but not in handgrip strength (HS). Patients assigned to the multidisciplinary program (n = 22) showed an improvement in both muscle mass [SMM (from 16.6 ± 6.0 to 17.3 ± 5.7 Kg, P = 0.050) and SMI (from 6.63 ± 1.65 to 6.91 ± 1.52 kg/m², P = 0.038)] and functional status [HS (from 13.5 ± 5.0 to 15.6 ± 6.7; P = 0.028), gait speed (from 0.44 ± 0.18 to 0.51 ± 0.20, P = 0.047) and Short Physical Performance Battery (from 4.6 ± 3.1 to 5.5 ± 3.2, P = 0.047)] at 6 months. The effect was no longer present after discontinuation of the intervention and was restored after its re-introduction at 12 months.

CONCLUSIONS

Nutritional and multidisciplinary interventions tailored on patient's functional status could be considered as strategies for the management of sarcopenia, a high prevalent condition in old adults living in long-term care institutions.

Creatine or vitamin D supplementation in individuals with a spinal cord injury undergoing resistance training: A double-blinded, randomized pilot trial

PURPOSE

Determine whether creatine or vitamin D supplementation improves muscle strength in individuals with spinal cord injury undergoing resistance training.

METHODS

Thirteen male and one female with spinal cord injury, from two Portuguese rehabilitation centers, were randomized to creatine (3g daily), vitamin D (25000 IU each two weeks) or placebo group in a double-blind design. All participants performed progressive resistance training during eight weeks. The outcome measures, obtained at baseline and after intervention, included: Sum of four skinfolds; Corrected arm muscle area; Seated medicine ball throw; Handgrip strength with dynamometer; Manual wheelchair slalom test and one repetition maximum for Chest press, Triceps, Pec deck and Lat pulldown. Vitamin D levels were obtained in all participants before and after intervention.

RESULTS

71.4% of participants had deficit values of vitamin D. The corrected arm muscle area improved significantly (p<0.05) in creatine group relatively to the control group. There was a significant correlation (p<0.05) between the one repetition maximum Pec deck and levels of vitamin D.

CONCLUSIONS

Supplementation with creatine may improve muscle strength parameters in individuals with spinal cord injury. Vitamin D deficiency is highly prevalent in this population. It is recommended an initial screening of vitamin D levels at the beginning of the physical rehabilitation process.

The association between 25-hydroxyvitamin D concentration, physical performance and frailty status in older adults

Purpose

Sufficient 25-hydroxyvitamin D (25(OH)D) concentrations might prevent a decline in physical performance, and are considered important for the prevention of frailty. This study investigates the association of serum 25(OH)D concentration with physical performance and frailty status in Dutch older adults.

Methods

This cross-sectional study included 756 men and women, aged ≥ 65 years. Serum 25(OH)D concentration and frailty status (Fried criteria) were assessed in the total population. Screening for frailty status included functional tests of gait speed and hand grip strength. In a subgroup (n = 494), the Timed Up and Go test (TUG) and knee-extension strength were measured. Associations of serum 25(OH)D status with physical performance were examined by multiple linear regression. Prevalence ratios (PR) were used to quantify associations between serum 25(OH)D deficiency (< 50 nmol/L) and frailty.

Results

In total, 45% of the participants were vitamin D deficient. Participants with vitamin D status < 50 and 50–75 nmol/L had significantly lower scores on the TUG and gait speed test, compared to participants with vitamin D status > 75 nmol/L. No significant associations with serum 25(OH)D concentrations were observed for handgrip strength or knee-extension strength. Participants with serum 25(OH)D status < 50 nmol/L were about two times more likely to be frail compared to participants with serum 25(OH)D status ≥ 50 nmol/L. No significant associations were observed between the pre-frail state and serum 25(OH)D status.

Conclusion

In this study, serum 25(OH)D concentrations were significantly associated with frailty status and measures of physical performance, including gait speed and TUG, but not with strength-related outcomes.

The Association of Vitamin D Status in Lower Extremity Muscle Strains and Core Muscle Injuries at the National Football League Combine

PURPOSE

To evaluate the association between serum vitamin D level and the prevalence of lower extremity muscle strains and core muscle injuries in elite level athletes at the National Football League (NFL) combine.

METHODS

During the 2015 NFL combine, all athletes with available serum vitamin D levels were included for study. Baseline data were collected, including age, race, body mass index, position, injury history specific to lower extremity muscle strain or core muscle injury, and Functional Movement Screen scores. Serum 25-hydroxyvitamin D was collected and defined as normal (≥32 ng/mL), insufficient (20-31 ng/mL), and deficient (<20 ng/mL). Univariate regression analysis was used to examine the association of vitamin D level and injury history. Subsequent multivariate regression analysis was used to examine this relation with adjustment for collected baseline data variables.

RESULTS

The study population included 214 athletes, including 78% African American athletes and 51% skilled position players. Inadequate vitamin D was present in 59%, including 10% with deficient levels. Lower extremity muscle strain or core muscle injury was present in 50% of athletes, which was associated with lower vitamin D levels (P = .03). Athletes with a positive injury history also showed significantly lower vitamin D levels as compared with uninjured athletes (P = .03). African American/black race (P < .001) and injury history (P < .001) was associated with lower vitamin D. Vitamin D groups showed no differences in age (P = .9), body mass index (P = .9), or Functional Movement Screen testing (P = .2). Univariate analysis of inadequate vitamin D levels showed a 1.86 higher odds of lower extremity strain or core muscle injury (P = .03), and 3.61 higher odds of hamstring injury (P < .001). Multivariate analysis did not reach an independent association of low vitamin D with injury history (P = .07).

CONCLUSIONS

Inadequate vitamin D levels are a widespread finding in athletes at the NFL combine. Players with a history of lower extremity muscle strain and core muscle injury had a higher prevalence of inadequate vitamin D.

LEVEL OF EVIDENCE

Level IV, retrospective study-case series.

The vitamin D receptor expression in skeletal muscle of women with distal radius fracture

We evaluated the vitamin D receptor (VDR) expression in the forearm flexor muscle of women with distal radius fracture. High VDR expression was associated with low appendicular lean mass index.

INTRODUCTION

We aimed to evaluate the relationship between the VDR expression in the muscle cell and the muscle mass in women with a distal radius fracture (DRF).

METHODS

We prospectively recruited 45 women over 50 years of age (mean age, 66 years) with DRF and acquired biopsy of the forearm flexor muscle. The muscle cross-sectional area (CSA) and VDR expression were measured using immunohistochemistry staining. The clinical parameters including grip strength, gait speed, body mass index (BMI), bone mineral density (BMD), and serum vitamin D levels were compared between patients grouped by appendicular lean mass index and were correlated with the VDR expression.

RESULTS

Twelve patients (27%) showed a decreased appendicular lean mass index, less than the cut-off value of 5.4 kg/m2 which was suggested by the Asian Working Group for Sarcopenia. Patients with a low appendicular lean mass index had significantly lower muscle CSA (p = 0.037), but a higher VDR expression (p = 0.045) than those with higher indices. VDR expression was negatively correlated with BMI (r = - 0.417, p = 0.004) and appendicular lean mass index (r = - 0.316, p = 0.044).

CONCLUSIONS

DRF patients with low appendicular lean mass index presented high VDR expression and low CSA in forearm muscle cells. This suggests that the VDR expression might be upregulated in the attempt to compensate for the decreasing muscle mass. Further studies are necessary to explore the role of VDR in the progression of sarcopenia.

A role for nutritional intervention in addressing the aging neuromuscular junction

The purpose of this review is to discuss the structural and physiological changes that underlie age-related neuromuscular dysfunction and to summarize current evidence on the potential role of nutritional interventions on neuromuscular dysfunction-associated pathways. Age-related neuromuscular deficits are known to coincide with distinct changes in the central and peripheral nervous system, in the neuromuscular system, and systemically. Although many features contribute to the age-related decline in neuromuscular function, a comprehensive understanding of their integration and temporal relationship is needed. Nonetheless, many nutrients and ingredients show promise in modulating neuromuscular output by counteracting the age-related changes that coincide with neuromuscular dysfunction. In particular, dietary supplements, such as vitamin D, omega-3 fatty acids, β-hydroxy-β-methylbutyrate, creatine, and dietary phospholipids, demonstrate potential in ameliorating age-related neuromuscular dysfunction. However, current evidence seldom directly assesses neuromuscular outcomes and is not always in the context of aging. Additional clinical research studies are needed to confirm the benefits of dietary supplements on neuromuscular function, as well as to define the appropriate population, dosage, and duration for intervention.

Impact of Western and Mediterranean Diets and Vitamin D on Muscle Fibers of Sedentary Rats

Background: The metabolic syndrome is associated with sarcopenia. Decreased serum levels of Vitamin D (VitD) and insulin-like growth factor (IGF)-1 and their mutual relationship were also reported. We aimed to evaluate whether different dietary profiles, containing or not VitD, may exert different effects on muscle molecular morphology. Methods: Twenty-eight male rats were fed for 10 weeks in order to detect early defects induced by different dietary regimens: regular diet (R); regular diet with vitamin D supplementation (R-DS) and regular diet with vitamin D restriction (R-DR); high-fat butter-based diets (HFB-DS and HFB-DR) with 41% energy from fat; high-fat extra-virgin olive oil-based diets (HFEVO-DS and HFEVO-DR) with 41% energy from fat. IL-1β, insulin-like growth factor (IGF)1, Dickkopf-1 (DKK-1), and VitD-receptor (VDR) expressions were evaluated by immunohistochemistry. Muscle fiber perimeter was measured by histology and morphometric analysis. Results: The muscle fibers of the HEVO-DS rats were hypertrophic, comparable to those of the R-DS rats. An inverse correlation existed between the dietary fat content and the perimeter of the muscle fibers (p < 0.01). In the HFB-DR rats, the muscle fibers appeared hypotrophic with an increase of IL-1β and a dramatic decrease of IGF-1 expression. Conclusions: High-fat western diet could impair muscle metabolism and lay the ground for subsequent muscle damage. VitD associated with a Mediterranean diet showed trophic action on the muscle fibers.

Vitamin D and Ageing

One hundred years has passed since the discovery of vitamin D as the active component of cod-liver oil which cured the bone disease rickets. Since then our knowledge of vitamin D has expanded tremendously and has included recognition of the importance of UV radiation as a source of the vitamin as well as the discovery of the vitamin as a nutrient, a pro-hormone and a potent steroid hormone with a major role in calcium and bone metabolism. In the last 25 years or so, the discovery of the vitamin D receptor in over 30 different body tissues together with the existence of the alpha-1-hydroxylase enzyme in these tissues provided evidence of a pleiotropic role of vitamin D outside its classical role in the skeleton. These important discoveries have provided the basis for the increasing interest in vitamin D in the context of nutritional requirements for health including the prevention of chronic diseases of ageing. The recent publication of the Dietary Reference Intake report on vitamin D and calcium by the North American Institute of Medicine (IOM) is the most comprehensive report to date on the basis for setting nutritional requirements for vitamin D. This chapter will summarize the nutritional aspects of vitamin D and discuss the changes in vitamin D metabolism and requirements with ageing. It will summarize key evidence on the relationship between vitamin D status and some of the main ageing related health outcomes including bone, muscle and cognitive health as well as survival focusing on the published literature in very-old adults (those >= 85 years of age).

Clodronate as a Therapeutic Strategy against Osteoarthritis

Osteoarthritis (OA), the most prevalent musculoskeletal pathology, is mainly characterized by the progressive degradation of articular cartilage due to an imbalance between anabolic and catabolic processes. Consequently, OA has been associated with defects in the chondrocitic differentiation of progenitor stem cells (PSCs). In addition, SOX9 is the transcription factor responsible for PSCs chondrogenic commitment. To evaluate the effects of the non-amino bisphosphonate clodronate in OA patients we investigated SOX9 gene expression in circulating progenitor cells (CPCs) and in an in vitro OA model. We evaluated pain intensity, mental and physical performance in OA patients, as well as serum biomarkers related to bone metabolism. In addition, in order to improve therapeutic strategies, we assayed nanoparticle-embedded clodronate (NPs-clo) in an in vitro model of chondrogenic differentiation. Our data showed upregulation of SOX9 gene expression upon treatment, suggesting an increase in chondrocytic commitment. Clodronate also reduced osteoarticular pain and improved mental and physical performance in patients. Furthermore, NPs-clo stimulated SOX9 expression more efficaciously than clodronate alone. Clodronate may therefore be considered a good therapeutic tool against OA; its formulation in nanoparticles may represent a promising challenge to counteract cartilage degeneration.

The Role of Inflammation in Age-Related Sarcopenia

Many physiological changes occur with aging. These changes often, directly or indirectly, result in a deterioration of the quality of life and even in a shortening of life expectancy. Besides increased levels of reactive oxygen species, DNA damage and cell apoptosis, another important factor affecting the aging process involves a systemic chronic low-grade inflammation. This condition has already been shown to be interrelated with several (sub)clinical conditions, such as insulin resistance, atherosclerosis and Alzheimer's disease. Recent evidence, however, shows that chronic low-grade inflammation also contributes to the loss of muscle mass, strength and functionality, referred to as sarcopenia, as it affects both muscle protein breakdown and synthesis through several signaling pathways. Classic interventions to counteract age-related muscle wasting mainly focus on resistance training and/or protein supplementation to overcome the anabolic inflexibility from which elderly suffer. Although the elderly benefit from these classic interventions, the therapeutic potential of anti-inflammatory strategies is of great interest, as these might add up to/support the anabolic effect of resistance exercise and/or protein supplementation. In this review, the molecular interaction between inflammation, anabolic sensitivity and muscle protein metabolism in sarcopenic elderly will be addressed.

The relationship of Physical performance and Osteoporosis prevention with vitamin D in older African Americans (PODA)

RATIONALE

Vitamin D deficiency is associated with bone loss, poor muscle strength, falls and fracture. This information in older African Americans (AAs) is sparse.

OBJECTIVE

The study of the relationship of Physical performance, Osteoporosis prevention with vitamin D in older African Americans (PODA) is a randomized, double-blind, placebo-controlled 3-year trial examining the effect of vitamin D on bone loss and physical performance in older AA women.

METHODS

260 healthy AA women aged >60years were assigned to receive placebo or vitamin D₃. Initial vitamin D₃ dose was determined by the baseline serum 25OHD level, and adjusted further to maintain serum 25OHD between 30 and 69ng/ml. Subjects with baseline 25OHD levels ≤8ng/ml or ≥26ng/ml were excluded. Objective measures of neuromuscular strength [Short Physical Performance Battery (SPPB), grip strength and 6-minute walking distance (6MWD)] and bone mineral density (BMD) were obtained.

RESULTS

SPPB gait speed, grip strength and 6MWD showed a significant positive correlation with free 25OHD. 1pg/ml increase in free 25OHD predicted a 32% increase in the odds of having higher gait speed and a 1.42lb. increase in grip strength. No significant differences in BMI, BMD, muscle mass, grip strength, serum total 25OHD and free 25OHD were observed between groups. None of the measures of physical performance showed an association with baseline serum 25OHD.

CONCLUSIONS

This is the first study to show an association between free 25OHD and physical performance. These findings indicate a positive relationship of free 25OHD with gait speed and grip strength in older AA women. Further studies are needed to understand the role of free 25OHD.

Effect of Vitamin D on Falls and Physical Performance

Recent understanding has highlighted the importance of extraskeletal role of vitamin D. Despite numerous observational and interventional studies over the last two decades, the apparent divergent clinical findings have intensified the controversy regarding this role of vitamin D in older adults. This article reviews the existing literature and summarizes the current knowledge of vitamin D status and vitamin D supplementation on falls and physical performance, describes the putative mechanisms underlying this association, and reflects on the controversy surrounding vitamin D recommendations in older adults.

Supplementing Breakfast with a Vitamin D and Leucine-Enriched Whey Protein Medical Nutrition Drink Enhances Postprandial Muscle Protein Synthesis and Muscle Mass in Healthy Older Men

Background: A promising strategy to help older adults preserve or build muscle mass is to optimize muscle anabolism through providing an adequate amount of high-quality protein at each meal.Objective: This "proof of principle" study investigated the acute effect of supplementing breakfast with a vitamin D and leucine-enriched whey protein medical nutrition drink on postprandial muscle protein synthesis and longer-term effect on muscle mass in healthy older adults.Methods: A randomized, placebo-controlled, double-blind study was conducted in 24 healthy older men [mean ± SD: age 71 ± 4 y; body mass index (in kg/m²) 24.7 ± 2.8] between September 2012 and October 2013 at the Unit of Human Nutrition, University of Auvergne, Clermont-Ferrand, France. Participants received a medical nutrition drink [test group; 21 g leucine-enriched whey protein, 9 g carbohydrates, 3 g fat, 800 IU cholecalciferol (vitamin D₃), and 628 kJ] or a noncaloric placebo (control group) before breakfast for 6 wk. Mixed muscle protein fractional synthesis rate (FSR) was measured at week 0 in the basal and postprandial state, after study product intake with a standardized breakfast with the use of l-[²H₅]-phenylalanine tracer methodology. The longer-term effect of the medical nutrition drink was evaluated by measurement of appendicular lean mass, representing skeletal muscle mass at weeks 0 and 6, by dual-energy X-ray absorptiometry.Results: Postprandial FSR (0-240 min) was higher in the test group than in the control group [estimate of difference (ED): 0.022%/h; 95% CI: 0.010%/h, 0.035%/h; ANCOVA, P = 0.001]. The test group gained more appendicular lean mass than the control group after 6 wk (ED: 0.37 kg; 95% CI: 0.03, 0.72 kg; ANCOVA, P = 0.035), predominantly as leg lean mass (ED: 0.30 kg; 95% CI: 0.03, 0.57 kg; ANCOVA, P = 0.034).Conclusions: Supplementing breakfast with a vitamin D and leucine-enriched whey protein medical nutrition drink stimulated postprandial muscle protein synthesis and increased muscle mass after 6 wk of intervention in healthy older adults and may therefore be a way to support muscle preservation in older people. This trial was registered at www.trialregister.nl as NTR3471.

The Effect of a 12-Week Health Training Program on Selected Anthropometric and Biochemical Variables in Middle-Aged Women

Regular moderate physical activity positively affects health, fitness, and body composition; it regulates the pro- and anti-inflammatory cytokines levels. Vitamin D plays an important regulatory role; its adequate levels correlate with low values of inflammation markers and an increase in muscle strength and fitness in exercising people. The study's aim was to evaluate changes in somatic variables, oxidative stress, and inflammation markers, as well as blood calcidiol concentration in middle-aged healthy women after 12 weeks of aerobics classes—endurance exercises, including choreographic sequences, aiming to improve fitness and motor coordination. The training led to a significant reduction of body mass and fat tissue; it induced an increase in lean body mass. After the 12-week training program, plasma antioxidant status increased (0.65 ± 0.21, p < 0.01) and the concentration of lipid peroxidation products decreased (0.07 ± 0.02, p < 0.001). A significant increase in plasma antioxidant status associated with training could have reduced the level of proinflammatory interleukin as indicated by a positive correlation between these variables (r_s = 0.64, p < 0.05). The study proved that a 12-week health training program in physically inactive middle-aged women might provide improvements in their anthropometric parameters and selected biochemical indicators.

Rhabdomyolysis and AKI with Atorvastatin and Sitagliptin Use in the Setting of Low 25-Hydroxyvitamin D Levels

We report a case of an 86-year-old woman admitted to the hospital with rhabdomyolysis and acute kidney injury 3 weeks after starting sitagliptin while on long-term atorvastatin therapy. She also had low levels of 25-hydroxyvitamin D and mild chronic kidney disease, which may have contributed to the development of rhabdomyolysis. A review of the literature reveals four previous reports of this drug interaction in elderly patients, some with underlying kidney disease.

Vitamin D, a modulator of musculoskeletal health in chronic kidney disease

The spectrum of activity of vitamin D goes beyond calcium and bone homeostasis, and growing evidence suggests that vitamin D contributes to maintain musculoskeletal health in healthy subjects as well as in patients with chronic kidney disease (CKD), who display the combination of bone metabolism disorder, muscle wasting, and weakness. Here, we review how vitamin D represents a pathway in which bone and muscle may interact. In vitro studies have confirmed that the vitamin D receptor is present on muscle, describing the mechanisms whereby vitamin D directly affects skeletal muscle. These include genomic and non-genomic (rapid) effects, regulating cellular differentiation and proliferation. Observational studies have shown that circulating 25-hydroxyvitamin D levels correlate with the clinical symptoms and muscle morphological changes observed in CKD patients. Vitamin D deficiency has been linked to low bone formation rate and bone mineral density, with an increased risk of skeletal fractures. The impact of low vitamin D status on skeletal muscle may also affect muscle metabolic pathways, including its sensitivity to insulin. Although some interventional studies have shown that vitamin D may improve physical performance and protect against the development of histological and radiological signs of hyperparathyroidism, evidence is still insufficient to draw definitive conclusions.

Cachexia at diagnosis is associated with poor survival in head and neck cancer patients

CONCLUSIONS

One third of the patients had cachexia with an association of significantly shorter survival. These results suggest that combining HGS and MAMA seems to be a practical method to screen cachexia in patients with head and neck cancer and may also be used when assessing their prognosis.

OBJECTIVES

The aim of this study was to analyze the hypothesis that cachexia defined as both low mid-arm muscle area (MAMA) and handgrip strength (HGS) is associated with decreased survival in patients with head and neck squamous cell carcinoma (HNSCC).

METHODS

Sixty-five consecutive patients with primary HNSCC were enrolled prior to cancer therapy. Cachexia was defined as low handgrip strength (HGS) and low mid-arm muscle area (MAMA). Nutritional status was assessed by patient-generated subjective global assessment (PG-SGA) and sarcopenia by low MAMA. Biochemical parameters reflecting nutritional status and S-25-OHD were measured.

RESULTS

Cachexia was seen in 31% and sarcopenia in 46% of patients. Altogether, 34% of patients were malnourished. Disease-free survival was 13 months (3-62) in cachectic patients, compared with 66 months (31-78) in non-cachectic patients (p = 0.009). S-25-OHD was 28 nmol/l in cachectic patients, compared with 46 nmol/l in non-cachectic patients (p = 0.009) and prealbumin 187 mg/l and 269 mg/l, respectively (p < 0.001).

[Common therapeutic approaches of sarcopenia in the elderly and uremic myopathy]

The gradual loss of weight and function of muscle in patients with chronic kidney disease as in the elderly impacts the quality of life. Early management should help slow the functional limitation. Physical activity is the first therapy to propose that ensures stability of muscle mass and improved function. Resistance training programs have proven effective but are not yet widely available in nephrology units. The nutritional management should not be forgotten because there is a resistance to anabolism and protein intake should be involved in physical activity program. Associated treatments should not be neglected: vitamin D, anti-inflammatory, androgens. Some are still under evaluation. Therapeutic option, tomorrow, could be anti-myostatin antibodies and glitazones.

Vitamin D supplementation in the prevention and management of major chronic diseases not related to mineral homeostasis in adults: research for evidence and a scientific statement from the European society for clinical and economic aspects of osteoporosis and osteoarthritis (ESCEO)

INTRODUCTION

Optimal vitamin D status promotes skeletal health and is recommended with specific treatment in individuals at high risk for fragility fractures. A growing body of literature has provided indirect and some direct evidence for possible extraskeletal vitamin D-related effects.

PURPOSE AND METHODS

Members of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis have reviewed the main evidence for possible proven benefits of vitamin D supplementation in adults at risk of or with overt chronic extra-skeletal diseases, providing recommendations and guidelines for future studies in this field.

RESULTS AND CONCLUSIONS

Robust mechanistic evidence is available from in vitro studies and in vivo animal studies, usually employing cholecalciferol, calcidiol or calcitriol in pharmacologic rather than physiologic doses. Although many cross-sectional and prospective association studies in humans have shown that low 25-hydroxyvitamin D levels (i.e., <50 nmol/L) are consistently associated with chronic diseases, further strengthened by a dose-response relationship, several meta-analyses of clinical trials have shown contradictory results. Overall, large randomized controlled trials with sufficient doses of vitamin D are missing, and available small to moderate-size trials often included people with baseline levels of serum 25-hydroxyvitamin D levels >50 nmol/L, did not simultaneously assess multiple outcomes, and did not report overall safety (e.g., falls). Thus, no recommendations can be made to date for the use of vitamin D supplementation in general, parental compounds, or non-hypercalcemic vitamin D analogs in the prevention and treatment of extra-skeletal chronic diseases. Moreover, attainment of serum 25-hydroxyvitamin D levels well above the threshold desired for bone health cannot be recommended based on current evidence, since safety has yet to be confirmed. Finally, the promising findings from mechanistic studies, large cohort studies, and small clinical trials obtained for autoimmune diseases (including type 1 diabetes, multiple sclerosis, and systemic lupus erythematosus), cardiovascular disorders, and overall reduction in mortality require further confirmation.

Association of serum vitamin D with osteosarcopenic obesity: Korea National Health and Nutrition Examination Survey 2008-2010

BACKGROUND

Serum vitamin D levels have been reported to be associated with individual components of body composition. However, the relationship between serum vitamin D and combined indices of adverse body composition is largely unknown. This cross-sectional study examined the association between serum vitamin D and osteosarcopenic obesity in a nationally representative sample of middle-aged and older adults.

METHODS

We analysed the Korea National Health and Nutrition Examination Surveys (IV and V) conducted in 2008-2010, consisting of 5908 (2485 men, 3423 women) aged ≥ 50 years. Serum vitamin D levels were determined by radioimmunoassay, and body composition was evaluated by dual-energy x-ray absorptiometry. The association between serum vitamin D levels and the number of abnormalities in body composition, including osteosarcopenic obesity, a low bone and muscle mass with concurrent high fat mass, was analysed by multinomial logistic regression adjusting for covariates.

RESULTS

In men, after controlling for covariates, higher vitamin D levels were associated with a significantly reduced likelihood of the number of phenotypes of adverse body composition (P for trend < 0.05). Those in the highest tertile group of serum vitamin D levels, compared with those in the lowest tertile, were less likely to have adverse body composition, numbering one (odds ratio [OR] = 0.67, 95% confidence interval [CI]: 0.49, 0.92), two (OR = 0.49, 95% CI: 0.33, 0.73), and three (osteosarcopenic obesity; OR = 0.42, 95% CI: 0.26, 0.67). In women, those in the highest tertile group of serum vitamin D levels, compared with those in the lowest tertile, were less likely to have osteosarcopenic obesity (OR = 0.55, 95% CI: 0.33, 0.93). Vitamin D deficiency (<20 ng/mL) in men was significantly associated with an increased likelihood of a higher number of adverse body composition, especially for osteosarcopenic obesity (OR = 2.08, 95% CI: 1.42, 3.03). Vitamin D deficient women, compared with those having normal levels of serum vitamin D, were also more likely to demonstrate osteosarcopenic obesity (OR = 1.99, 95% CI: 1.30, 3.05).

CONCLUSIONS

A high serum vitamin D level in mid- and late-life was associated with reduced odds of multiple adverse body composition, especially osteosarcopenic obesity, suggesting potential health benefits of maintaining adequate levels of vitamin D.

Reduced fetal vitamin D status by maternal undernutrition during discrete gestational windows in sheep

Placental transport of vitamin D and other nutrients (e.g. amino acids, fats and glucose) to the fetus is sensitive to maternal and fetal nutritional cues. We studied the effect of maternal calorific restriction on fetal vitamin D status and the placental expression of genes for nutrient transport [aromatic T-type amino acid transporter-1 (TAT-1); triglyceride hydrolase/lipoprotein uptake facilitator lipoprotein lipase (LPL)] and vitamin D homeostasis [CYP27B1; vitamin D receptor (VDR)], and their association with markers of fetal cardiovascular function and skeletal muscle growth. Pregnant sheep received 100% total metabolizable energy (ME) requirements (control), 40% total ME requirements peri-implantation [PI40, 1-31 days of gestation (dGA)] or 50% total ME requirements in late gestation (L, 104-127 dGA). Fetal, but not maternal, plasma 25-hydroxy-vitamin D (25OHD) concentration was lower in PI40 and L maternal undernutrition groups (P<0.01) compared with the control group at 0.86 gestation. PI40 group placental CYP27B1 messenger RNA (mRNA) levels were increased (P<0.05) compared with the control group. Across all groups, higher fetal plasma 25OHD concentration was associated with higher skeletal muscle myofibre and capillary density (P<0.05). In the placenta, higher VDR mRNA levels were associated with higher TAT-1 (P<0.05) and LPL (P<0.01) mRNA levels. In the PI40 maternal undernutrition group only, reduced fetal plasma 25OHD concentration may be mediated in part by altered placental CYP27B1. The association between placental mRNA levels of VDR and nutrient transport genes suggests a way in which the placenta may integrate nutritional cues in the face of maternal dietary challenges and alter fetal physiology.

No mediating effects of glycemic control and inflammation on the association between vitamin D and lung function in the general population

BACKGROUND

Vitamin D deficiency is discussed to be associated with lung health. While former studies focused on subjects suffering from pulmonary diseases, we aimed to investigate the association of 25-hydroxy vitamin D [25(OH)D] with lung function in the general population and examined whether mediating effects of inflammation, glycemic control or renal function exist.

METHODS

1404 participants from the Study of Health in Pomerania with pulmonary function testing assessed by expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), total lung capacity and Krogh index were used. Adjusted analysis of variance, linear regression models and mediation analyses were performed.

RESULTS

Significant positive associations between 25(OH)D levels and FEV₁, FVC and Krogh index were found. Mediator analyses revealed no mediating effect of inflammation (fibrinogen), glycemic control (HbA1c) or renal function (eGFR) on associations with FEV₁ or FVC. With respect to Krogh-Index, the association to 25(OH)D was slightly mediated by fibrinogen with a proportion mediated of 9.7%.

CONCLUSION

Significant positive associations of 25(OH)D with lung function were revealed in a general population. The proposed mediating effects of inflammation, glycemic control and renal function on these relations were not confirmed. Further studies examining the causality of the association between 25(OH)D and lung function are necessary.

Omega-3 Fatty Acids and Vitamin D in Immobilisation: Part B- Modulation of Muscle Functional, Vascular and Activation Profiles

OBJECTIVES

This study set out to determine whether two potential protein-sparing modulators (eicosapentaenoic acid and vitamin D) would modulate the anticipated muscle functional and related blood vessels function deleterious effects of immobilisation.

DESIGN

The study used a randomised, double-blind, placebo-controlled design.

SETTING

The study took part in a laboratory setting.

PARTICIPANTS

Twenty-four male and female healthy participants, aged 23.0±5.8 years.

INTERVENTION

The non-dominant arm was immobilised in a sling for a period of nine waking hours a day over two continuous weeks. Participants were randomly assigned to one of three groups: placebo (n=8, Lecithin, 2400 mg daily), omega-3 (ω-3) fatty acids (n=8, eicosapentaenoic acid (EPA); 1770 mg, and docosahexaenoic acid (DHA); 390 mg, daily) or vitamin D (n=8, 1,000 IU daily).

MEASUREMENTS

Isometric and isokinetic torque, antagonist muscle co-contraction (activation profile), muscle fatigability indices, and arterial resting blood flow were measured before, at the end of the immobilisation period, and two weeks after re-mobilisation.

RESULTS

Muscle elbow flexion and extension isometric and isokinetic torque decreased significantly with limb immobilisation in the placebo group (P<0.05). Despite no significant effect of supplementation, ω-3 and vitamin D supplementation showed trends (P>0.05) towards attenuating the decreases observed in the placebo group. There was no significant change in muscle fatigue parameters or co-contraction values with immobilisation and no effect of supplementation group (P>0.05). Similarly, this immobilisation model had no impact on the assessed blood flow characteristics. All parameters had returned to baseline values at the re-mobilisation phase of the study.

CONCLUSION

Overall, at the current doses, neither ω-3 nor vitamin D supplementation significantly attenuated declines in torque associated with immobilisation. It would appear that muscle function (described here in Part B) might not be as useful a marker of the effectiveness of a supplement against the impact of immobilisation compared to tissue composition changes (described in Part A).

Omega-3 Fatty Acids and Vitamin D in Immobilisation: Part A- Modulation of Appendicular Mass Content, Composition and Structure

OBJECTIVES

Muscle size decreases in response to short-term limb immobilisation. This study set out to determine whether two potential protein-sparing modulators (eicosapentaenoic acid and vitamin D) would attenuate immobilisation-induced changes in muscle characteristics.

DESIGN

The study used a randomised, double-blind, placebo-controlled design.

SETTING

The study took part in a laboratory setting.

PARTICIPANTS

Twenty-four male and female healthy participants, aged 23.0±5.8 years.

INTERVENTION

The non-dominant arm was immobilised in a sling for a period of nine waking hours a day over two continuous weeks. Participants were randomly assigned to one of three groups: placebo (n=8, Lecithin, 2400 mg daily), omega-3 (ω-3) fatty acids (n=8, eicosapentaenoic acid (EPA); 1770 mg, and docosahexaenoic acid (DHA); 390 mg, daily) or vitamin D (n=8, 1,000 IU daily).

MEASUREMENTS

Muscle and sub-cutaneous adipose thickness (B-mode ultrasonography), body composition (DXA) and arm girth (anthropometry) were measured before immobilisation, immediately on removal of the sling and two weeks after re-mobilisation.

RESULTS

Muscle thickness (-5.4±4.3%), upper and lower arm girth (-1.3±0.4 and -0.8±0.8%, respectively), lean mass (-3.6±3.7%) and bone mineral content (BMC) (-2.3±1.5%) decreased significantly with limb immobilisation in the placebo group (P<0.05). Despite no significant effect of group, ω-3 and vitamin D supplementation showed trends (p>0.05) towards attenuating the decreases in muscle thickness, upper/lower arm girths and BMC observed in the placebo group. The ω-3 supplementation group demonstrated a non-significant attenuation of the decrease in DXA quantified lean mass observed in the placebo group. Sub-cutaneous adipose thickness increased in the placebo group (P<0.05). ω-3 and vitamin D both blunted this response, with ω-3 having a greater effect (P<0.05). All parameters had returned to baseline values at the re-mobilisation phase of the study.

CONCLUSION

Overall, at the current doses, ω-3 and vitamin D supplementation only attenuated one of the changes associated with non-injurious limb immobilisation. These findings would necessitate further research into either a) supplementation linked to injury-induced immobilisation, or b) larger doses of these supplements to confirm/refute the physiological reserve potential of the two supplements.

The Vitamin D Assessment (ViDA) Study: design of a randomized controlled trial of vitamin D supplementation for the prevention of cardiovascular disease, acute respiratory infection, falls and non-vertebral fractures

Observational studies have shown that low vitamin D status is associated with an increased risk of cardiovascular disease, acute respiratory infection, falls and non-vertebral fractures. We recruited 5110 Auckland adults, aged 50-84 years, into a randomized, double-blind, placebo-controlled trial to test whether vitamin D supplementation protects against these four major outcomes. The intervention is a monthly cholecalciferol dose of 100,000IU (2.5mg) for an estimated median 3.3 years (range 2.5-4.2) during 2011-2015. Participants were recruited primarily from family practices, plus community groups with a high proportion of Maori, Pacific, or South Asian individuals. The baseline evaluation included medical history, lifestyle, physical measurements (e.g. blood pressure, arterial waveform, lung function, muscle function), and a blood sample (stored at -80°C for later testing). Capsules are being mailed to home addresses with a questionnaire to collect data on non-hospitalized outcomes and to monitor adherence and potential adverse effects. Other data sources include New Zealand Ministry of Health data on mortality, hospitalization, cancer registrations and dispensed pharmaceuticals. A random sample of 438 participants returned for annual collection of blood samples to monitor adherence and safety (hypercalcemia), including repeat physical measurements at 12 months follow-up. The trial will allow testing of a priori hypotheses on several other endpoints including: weight, blood pressure, arterial waveform parameters, heart rate variability, lung function, muscle strength, gait and balance, mood, psoriasis, bone density, and chronic pain.

Sarcopenia in critically ill patients

Sarcopenia occurring as a primary consequence of aging and secondary due to certain medical problems including chronic disease, malnutrition and inactivity is a progressive generalized loss of skeletal muscle mass, strength and function. The prevalence of sarcopenia increases with aging (approximately 5-13 % in the sixth and seventh decades). However, data showing the prevalence and clinical outcomes of sarcopenia in intensive care units (ICUs) are limited. A similar condition to sarcopenia in the ICU, called ICU-acquired weakness (ICU-AW), has been reported more frequently. Here, we aim to examine the importance of sarcopenia, especially ICU-AW, in ICU patients via related articles in Medline.

Vitamin D and/or calcium deficient diets may differentially affect muscle fiber neuromuscular junction innervation

INTRODUCTION

There is evidence that supports a role for Vitamin D (Vit. D) in muscle. The exact mechanism by which Vit. D deficiency impairs muscle strength and function is not clear.

METHODS

Three-week-old mice were fed diets with varied combinations of Vit. D and Ca²⁺ deficiency. Behavioral testing, genomic and protein analysis, and muscle histology were performed with a focus on neuromuscular junction (NMJ) -related genes.

RESULTS

Vit. D and Ca²⁺ deficient mice performed more poorly on given behavioral tasks than animals with Vit. D deficiency alone. Genomic and protein analysis of the soleus and tibialis anterior muscles revealed changes in several Vit. D metabolic, NMJ-related, and protein chaperoning and refolding genes.

CONCLUSIONS

These data suggest that detrimental effects of a Vit. D deficient or a Vit. D and Ca²⁺ deficient diet may be a result of differential alterations in the structure and function of the NMJ and a lack of a sustained stress response in muscles. Muscle Nerve 54: 1120-1132, 2016.

Effect of 12-Week Vitamin D Supplementation on 25[OH]D Status and Performance in Athletes with a Spinal Cord Injury

(1) BACKGROUND: studies with able-bodied athletes showed that performance might possibly be influenced by vitamin D status. Vitamin D seems to have a direct impact on neuromuscular function by docking on vitamin D receptors in the muscle tissue. Additionally, a high prevalence of vitamin D deficiency was shown not only in infants and in the elderly but also in healthy adults and spinal cord injured individuals. Therefore, the aim of our study was to investigate whether a vitamin D dose of 6000 IU daily over 12 weeks would be sufficient to increase vitamin D status in indoor wheelchair athletes to a normal or optimal vitamin D level and whether vitamin D deficiency is associated with an impairment in muscle performance in these individuals; (2) METHODS: vitamin D status was assessed in indoor elite wheelchair athletes in order to have a baseline measurement. If vitamin D status was below 75 nmol/L, athletes were supplemented with 6000 IU of vitamin D daily over 12 weeks. A vitamin D status over 75 nmol/L was supplemented with a placebo supplement. Vitamin D status, as well as a Wingate test and an isokinetic dynamometer test, were performed at baseline and after six and 12 weeks; (3) RESULTS: 20 indoor elite wheelchair athletes participated in this double-blind study. All of these athletes showed an insufficient vitamin D status at baseline and were, therefore, supplemented with vitamin D. All athletes increased vitamin D status significantly over 12 weeks and reached an optimal level. Wingate performance was not significantly increased. Isokinetic dynamometer strength was significantly increased but only in the non-dominant arm in isometric and concentric elbow flexion; (4) CONCLUSION: a dose of 6000 IU of vitamin D daily over a duration of 12 weeks seems to be sufficient to increase vitamin D status to an optimal level in indoor wheelchair athletes. It remains unclear, whether upper body performance or muscle strength and vitamin D status are associated with each other.

Impact of Vitamin D Supplementation on Gross Motor Development of Healthy Term Infants: A Randomized Dose-Response Trial

In addition to benefits for bone health, vitamin D is implicated in muscle function in children and adults.

AIMS

To determine if vitamin D dosage positively correlated with gross motor development at 3 and 6 months of age. We hypothesized that higher doses would be associated with higher scores for gross motor skills.

METHODS

A consecutive sample of 55 healthy, term, and breastfed infants from Montreal, Canada were recruited from a randomized trial of vitamin D supplementation between 2009 and 2012. Infants were randomized to 400 International Units (IU) (n = 19), 800 IU (n = 18) or 1,200 IU (n = 18) vitamin D3/day. Motor performance at 3 and 6 months was quantified by the Alberta Infant Motor Scale (AIMS). Plasma vitamin D3 metabolites were measured by tandem mass spectrometry.

RESULTS

AIMS scores did not differ at 3 months. However, total AIMS scores and sitting subscores were significantly higher at 6 months in infants receiving 400 IU/day compared to 800 IU/day and 1,200 IU/day groups (p < .05). There were weak negative correlations with length and C-3 epimer of 25(OH)D.

CONCLUSIONS

In contrast to our hypothesis, gross motor achievements were significantly higher in infants receiving 400 IU/day vitamin D. Our findings also support longer infants being slightly delayed.

25(OH)D Status of Elite Athletes with Spinal Cord Injury Relative to Lifestyle Factors

Background: Due to the potential negative impact of low Vitamin D status on performance-related factors and the higher risk of low Vitamin D status in Spinal Cord Injury (SCI) population, research is warranted to determine whether elite athletes with SCI have sufficient 25(OH)D levels. The purposes of this study were to examine: (1) the seasonal proportion of vitamin D insufficiency among elite athletes with SCI; and (2) to determine whether lifestyle factors, SCI lesion level, and muscle performance/function are related to vitamin D status in athletes with SCI. Methods: Thirty-nine members of the Canadian Wheelchair Sports Association, and the US Olympic Committee Paralympic program from outdoor and indoor sports were recruited for this study. Dietary and lifestyle factors, and serum 25(OH)D concentrations were assessed during the autumn (October) and winter (February/March). An independent t-test was used to assess differences in 25(OH)D status among seasons, and indoor and outdoor sports in the autumn and winter, respectively. Results: Mean ± SD serum 25(OH)D concentration was 69.6 ± 19.7 nmol/L (range from 30 to 107.3 nmol/L) and 67.4 ± 25.5 nmol/L (range from 20 to 117.3 nmol/L)in the autumn and winter, respectively. In the autumn, 15.4% of participants were considered vitamin D deficient (25(OH)D < 50 nmol/L) whereas 51.3% had 25(OH)D concentrations that would be considered insufficient (<80 nmol/L). In the winter, 15.4% were deficient while 41% of all participants were considered vitamin D insufficient. Conclusion: A substantial proportion of elite athletes with SCI have insufficient (41%–51%) and deficient (15.4%) 25(OH)D status in the autumn and winter. Furthermore, a seasonal decline in vitamin D status was not observed in the current study.

Correlation between vitamin D levels and muscle fatigue risk factors based on physical activity in healthy older adults

PURPOSE

The purpose of this study was to investigate the relationship of serum vitamin D levels with physical activity, obesity, muscle fatigue biomarkers, and total antioxidant capacity (TAC) in healthy older adults.

METHODS

A total of 85 healthy older subjects aged 64-96 years were recruited in this study. Based on estimated energy expenditure scores, the participants were classified into three groups: inactive (n=25), moderate (n=20), and physically active (n=35). Serum 25(OH)D (25-hydroxy vitamin D) levels, metabolic syndrome parameters, TAC activity, muscle fatigue biomarkers (Ca, creatine kinase, lactic acid dehydrogenase, troponin I, hydroxyproline), physical activity, body fatness, and fatigue score (visual analog scale) were estimated using immunoassay techniques and prevalidated questionnaires, respectively.

RESULTS

Physical activity was estimated in 64.6% of the participants. Males showed higher physical activity (42.5%) compared to females (26.25%). Compared to participants with lower activity, significant reduction in body mass index, waist circumference, hips, fasting blood sugar, triglycerides, total cholesterol, HDL-cholesterol, and LDL-cholesterol were observed in moderate and physically active participants. Also, significant increase in the levels of serum 25(OH)D concentrations, calcium, and TAC activity along with reduction in the levels of muscle fatigue biomarkers: creatine kinase, lactic acid dehydrogenase, troponin I, hydroxyproline, and fatigue scores (visual analog scale) were reported in physically active participants compared to those of lower physical activity. In all participants, serum 25(OH)D concentrations correlated positively with Ca, TAC, physical activity scores, and negatively with body mass index, lipid profile, fatigue scores (visual analog scale), and muscle fatigue biomarkers. Stepwise regression analysis showed that serum 25(OH)D concentrations, physical activity, Ca, TAC, and demographic parameters explained approximately 61.4%-85.8% of reduction in both fatigue scores and muscle fatigue biomarkers with substantial improvement in muscle performance in healthy older adults.

CONCLUSION

The data showed that considerable levels of 25(OH)D concentrations, calcium intake, and lower obesity positively correlated with the improvement in the muscle relief and performance of physically active participants. These results demonstrate that 25(OH)D concentrations and calcium might prevent muscle fatigue by regulation of the biosynthesis of creatine kinase, lactic acid dehydrogenase, troponin I, and hydroxyproline via a proposed antifree radical mechanism reported by higher TAC activity. It was suggested that vitamin D status could be reported as a marker of the improvement of muscle performance, especially in healthy older adults with lower physical activity.

Vitamin D deficiency impairs skeletal muscle function in a smoking mouse model

Chronic obstructive pulmonary disease (COPD) is associated with skeletal muscle dysfunction. Vitamin D plays an important role in muscle strength and performance in healthy individuals. Vitamin D deficiency is highly prevalent in COPD, but its role in skeletal muscle dysfunction remains unclear. We examined the time-course effect of vitamin D deficiency on limb muscle function in mice with normal or deficient vitamin D serum levels exposed to air or cigarette smoke for 6, 12 or 18 weeks. The synergy of smoking and vitamin D deficiency increased lung inflammation and lung compliance from 6 weeks on with highest emphysema scores observed at 18 weeks. Smoking reduced body and muscle mass of the soleus and extensor digitorum longus (EDL), but did not affect contractility, despite type II atrophy. Vitamin D deficiency did not alter muscle mass but reduced muscle force over time, downregulated vitamin D receptor expression, and increased muscle lipid peroxidation but did not alter actin and myosin expression, fiber dimensions or twitch relaxation time. The combined effect of smoking and vitamin D deficiency did not further deteriorate muscle function but worsened soleus mass loss and EDL fiber atrophy at 18 weeks. We conclude that the synergy of smoking and vitamin D deficiency in contrast to its effect on lung disease, had different, independent but important noxious effects on skeletal muscles in a mouse model of mild COPD.