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

Sarcopenia in Distal Radius Fractures: A Scoping Review

BACKGROUND

Sarcopenia is an emerging disease that adversely impacts outcomes of older adults across the spectrum of fragility fractures. Few studies have examined sarcopenia in upstream fragility fractures such as the distal radius. Understanding the state of current evidence is essential in defining a research agenda in this critical area of sentinel distal radius fractures and sarcopenia.

OBJECTIVES

The aim of this scoping review was to summarize existing literature on sarcopenia in distal radius fracture in older adults, and to identify research areas and gaps to guide future studies.

METHODS

We utilized the 5-stage framework of Arksey and O'Malley. We searched studies from 2010 to 2020 relating to «Sarcopenia» and «Distal radius fractures» in major databases. Two reviewers independently screened articles for inclusion and conducted full text reviews of shortlisted articles. We extracted data on research areas, key findings, and study limitations.

RESULTS

Thirteen studies met the inclusion and exclusion criteria. They covered the areas of epidemiology (N=9), risk factors (N=4), basic science (N=2), outcomes (N=1), and diagnostic modalities (N=1). There were no studies on screening/case finding, prognostic scoring, intervention, or health economics. Identified limitations included the lack of clear definition and diagnostic criteria for sarcopenia, and lack of, or inappropriate, control group. Majority of studies were retrospective or cross-sectional in study design.

CONCLUSIONS

This scoping review on sarcopenia in distal radius fractures highlighted gaps in research areas and in the rigor of studies conducted, and the need for more prospective cohort and interventional studies. Building upon current consensus criteria, we propose setting a research agenda along the timeline of sarcopenia management, from screening through to intervention and follow-up, which will inform future research in this early disease cohort of fragility fractures.

Serum Vitamin D Levels in Patients With Distal Radius Fractures Presenting to a Tertiary Care Hospital

Objective To compare the frequency of serum vitamin D levels in patients with and without distal radius fracture. Introduction Hypovitaminosis D is a common problem worldwide. Deficiency of vitamin D is not only associated with musculoskeletal problems, but also with chronic diseases like diabetes mellitus, cardiovascular disease and cancer. Vitamin D deficiency results in bone pain, aggravating osteoporosis and fragility fractures. Distal radius fractures are common upper limb fractures, mostly in the elderly population. Low serum levels of vitamin D have been reported to result in increased risk of distal radius fracture. Methodology This study was conducted at The Indus Hospital Karachi, from 1st March 2020 to 31st August 2020. Consecutive non-probability sampling was done. Patients aged between 20 to 80 years with and without distal radius fractures were enrolled and serum vitamin D levels were compared. Results A total of 130 patients were enrolled in this study, out of which 70 (53.8%) were males. The median (IQR) vitamin D, calcium, alkaline phosphate level, and albumin was 14.8 (9.5-23) ng/ml, 9.2 (8.9-9.5) ng/ml, 91 (77.3-111) U/L, and 4.2 (4-4.5) g/dl, respectively. No significant association between distal radius fracture and vitamin D levels was found in males, whereas a significantly higher proportion of females with no fracture had a mild-moderate deficiency in comparison to females with fracture. Conclusion No significant association was noted between patients with and without distal radius fracture and vitamin D levels, however, we recommend more studies on this topic so that more comprehensive results can be obtained.

A longitudinal histologic evaluation of vitamin D receptor expression in the skeletal muscles of patients with a distal radius fracture

We investigated the effect of vitamin D supplementation on the expression of muscle vitamin D receptor (VDR) and cross-sectional area (CSA) in patients with a distal radius fracture (DRF). Significant increases in VDR expression and CSA were observed, especially in vitamin D-deficient patients.

PURPOSE

Vitamin D supplementation is known to enhance muscle mass and function, but whether the VDR is essential in this process remains unknown. We evaluated the change in VDR expression and CSA in the forearm muscles following vitamin D supplementation in patients with a DRF.

METHODS

We prospectively recruited 18 women with a median age of 63.5 years who have a DRF. We obtained two biopsies of the forearm muscle, first at the time of fracture repair and then during hardware removal. We supplemented 1000 IU of vitamin D per day during a median interval of 8 months. We examined the changes in VDR expression and CSA by immunohistochemistry.

RESULTS

The median serum 25-hydroxyvitamin D [25(OH)D] increased from 14.3 to 32.1 ng/mL (P = 0.001). The median VDR expression increased from 0.72 to 0.78 (P = 0.002), and the median CSA increased from 1290.0 to 1685.8 μm² (P = 0.022). Significant increases in VDR expression and CSA were observed in vitamin D-deficient patients [25(OH)D] < 20 ng/mL, but not in vitamin D-non-deficient patients. The changes in VDR expression and CSA were in the same direction in 13 patients, but in the opposite direction in 5 patients.

CONCLUSION

Vitamin D supplementation may increase muscle VDR expression and CSA in patients with a DRF, especially in vitamin D-deficient patients. The increase in CSA without an increase in VDR expression in some patients indicates that the effect of vitamin D supplementation on muscle mass could be mediated by indirect effect of serum vitamin D restoration and by VDR.

Asian Working Group for Sarcopenia: 2019 Consensus Update on Sarcopenia Diagnosis and Treatment

Clinical and research interest in sarcopenia has burgeoned internationally, Asia included. The Asian Working Group for Sarcopenia (AWGS) 2014 consensus defined sarcopenia as "age-related loss of muscle mass, plus low muscle strength, and/or low physical performance" and specified cutoffs for each diagnostic component; research in Asia consequently flourished, prompting this update. AWGS 2019 retains the previous definition of sarcopenia but revises the diagnostic algorithm, protocols, and some criteria: low muscle strength is defined as handgrip strength <28 kg for men and <18 kg for women; criteria for low physical performance are 6-m walk <1.0 m/s, Short Physical Performance Battery score ≤9, or 5-time chair stand test ≥12 seconds. AWGS 2019 retains the original cutoffs for height-adjusted muscle mass: dual-energy X-ray absorptiometry, <7.0 kg/m2 in men and <5.4 kg/m2 in women; and bioimpedance, <7.0 kg/m2 in men and <5.7 kg/m2 in women. In addition, the AWGS 2019 update proposes separate algorithms for community vs hospital settings, which both begin by screening either calf circumference (<34 cm in men, <33 cm in women), SARC-F (≥4), or SARC-CalF (≥11), to facilitate earlier identification of people at risk for sarcopenia. Although skeletal muscle strength and mass are both still considered fundamental to a definitive clinical diagnosis, AWGS 2019 also introduces "possible sarcopenia," defined by either low muscle strength or low physical performance only, specifically for use in primary health care or community-based health promotion, to enable earlier lifestyle interventions. Although defining sarcopenia by body mass index-adjusted muscle mass instead of height-adjusted muscle mass may predict adverse outcomes better, more evidence is needed before changing current recommendations. Lifestyle interventions, especially exercise and nutritional supplementation, prevail as mainstays of treatment. Further research is needed to investigate potential long-term benefits of lifestyle interventions, nutritional supplements, or pharmacotherapy for sarcopenia in Asians.

Evaluation and Management of Osteoporosis and Sarcopenia in Patients with Distal Radius Fractures

Distal radius fractures (DRFs) are one of the most common fractures seen in elderly people. Patients with DRFs have a high incidence of osteoporosis and an increased risk of subsequent fractures, subtle early physical performance changes, and a high prevalence of sarcopenia. Since DRFs typically occur earlier than vertebral or hip fractures, they reflect early changes of the bone and muscle frailty and provide physicians with an opportunity to prevent progression of frailty and secondary fractures. In this review, we will discuss the concept of DRFs as a medical condition that is at the start of the fragility fracture cascade, recent advances in the diagnosis of bone fragility including emerging importance of cortical porosity, fracture healing with osteoporosis medications, and recent progress in research on sarcopenia in patients with DRFs.

Altered gene and protein expressions of vitamin D receptor in skeletal muscle in sarcopenic patients who sustained distal radius fractures

Despite the presence of vitamin D receptor (VDR) in skeletal muscle cells, the relationship between VDR expressions and muscle mass or function has not been well studied. The purpose of this study was to compare VDR gene and protein expression in the forearm muscle between sarcopenic and non-sarcopenic individuals who have sustained distal radius fractures. Twenty samples of muscle tissue from sarcopenic patients (mean age 63.4 ± 8.1 years) and 20 age- and sex-matched control tissues (62.1 ± 7.9 years) were acquired from the edge of dissected pronator quadratus muscle during surgery for distal radius fractures. The mRNA expression levels of VDR as well as the myokines of interest that may be associated with muscle mass change (myogenin and myostatin) were analyzed with real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). In addition, Western blot assay and immunohistochemistry for VDR were performed. Sarcopenic patients showed a significantly lower level of gene expression for VDR and myogenin, but a greater level of gene expression for myostatin than the controls according to qRT-PCR analysis. The density of VDR protein expressions was 2.1 times greater, while that of myostatin was 2.6 times lower, in the control group than in the sarcopenic group according to Western blot analysis. On immunohistochemical analysis, the density of the cells expressing VDR was significantly decreased in the sarcopenic patients. Sarcopenic patients who sustained distal radius fractures presented lower vitamin D receptor gene and protein expression in skeletal muscles compared to non-sarcopenic individuals.