[Allopurinol and its role in the treatment of sarcopenia]

The association of allopurinol with persistent physical disability and frailty in a large community based older cohort

BACKGROUND

The protective effects of allopurinol on physical function in older adults are not well understood, despite its potential to improve functional gains and reduce sarcopenia. This study aims to determine the association between allopurinol, persistent physical disability, and frailty in older gout patients.

METHODS

This analysis used data from a randomized trial in an older cohort, ASPirin in Reducing Events in the Elderly (ASPREE). ASPREE recruited 19,114 participants aged ≥65 years without prior cardiovascular events, dementia, or independence-limiting physical disability at trial enrolment. This analysis examined the association of baseline and time-varying allopurinol use with persistent physical disability and new-onset frailty in participants with gout at baseline (self-report or use of any anti-gout medications). Frailty was measured using the Fried frailty phenotype (score ≥3/5) and a deficit accumulation frailty index (FI) (score >0.21/1.0). Multivariable Cox proportional-hazards models were used for main analyses.

RESULTS

This analysis included 1155 gout participants, with 630 taking allopurinol at baseline and 525 not. During a median follow-up of 5.7 years, 113 new allopurinol users were identified. Compared with nonusers, baseline allopurinol use was associated with a significant risk reduction of persistent physical disability (Adjusted HR 0.46, 95% CI 0.23-0.92, p = 0.03). The strength of the association was modestly attenuated in the time-varying analysis (Adjusted HR 0.56, 0.29-1.08, p = 0.08). No significant associations with frailty measures were observed for either baseline allopurinol use (Fried frailty: Adjusted HR 0.83, 0.62-1.12; FI: Adjusted HR 0.96, 0.74-1.24) or time-varying allopurinol use (Fried frailty: Adjusted HR 0.92, 0.69-1.24; FI: Adjusted HR 1.02, 0.78-1.33).

CONCLUSIONS

Allopurinol use in older adults with gout is associated with a reduced risk of persistent physical disability but not associated with risk of frailty.

Association between body fat and sarcopenia in older adults with type 2 diabetes mellitus: A cross-sectional study

OBJECTIVES

To investigate the association between body fat (BF%) and sarcopenia in older adults with type 2 diabetes mellitus (T2DM) and potential link with increased levels of inflammatory indicators and insulin resistance.

METHODS

A total of 543 older adults with T2DM were included in this cross-sectional study. Appendicular skeletal muscle (ASM), handgrip strength and gait speed were measured to diagnose sarcopenia according to the updated Asian Working Group for Sarcopenia (AWGS) 2019 criteria. Body composition data were tested using dual-energy X-ray absorptiometry (DEXA). Levels of serum high-sensitive C-reactive protein (hs-CRP), interleukin-6, fasting blood insulin (FINS), hemoglobin A1c (HbA1c), 25-hydroxyvitamin D₃ [25(OH) D₃] were also determined.

RESULTS

The prevalence of sarcopenia in all participants was 8.84%, of which 11.90% were male and 5.84% females. The Pearson's correlation analysis revealed that BF% was negatively correlated with gait speed in men and women (R =-0.195, P=0.001; R = -0.136, P =0.025, respectively). After adjusting for all potential confounders, sarcopenia was positive associated with BF% (male, OR: 1.38, 95% CI: 1.15-1.65, P< 0.001; female, OR: 1.30, 95% CI: 1.07-1.56, P=0.007), and negatively associated with body mass index (BMI) (male, OR: 0.57, 95% CI: 0.44-0.73, P<0.001; female, OR: 0.48, 95% CI: 0.33-0.70, P<0.001). No significant differences were found in hs-CRP, interleukin-6, and insulin resistance between older T2DM adults with and without sarcopenia.

CONCLUSION

Higher BF% was linked to an increased risk of sarcopenia in older adults with T2DM, suggesting the importance of assessing BF% rather than BMI alone to manage sarcopenia.

Musculoskeletal Ultrasound Shows Muscle Mass Changes during Post-Acute Care Hospitalization in Older Men: A Prospective Cohort Study

This study aimed to prospectively assess changes in muscle thickness (MT) and the cross-sectional area (CSA) of the rectus femoris (RF) muscle in a cohort of older adults, using musculoskeletal ultrasound at admission and at a 2-week follow-up during hospitalization in a post-acute care unit. Differences in frailty status and correlations of MT-RF and CSA-RF with current sarcopenia diagnostic criteria were also studied. Forty adults aged 79.5 (SD 9.5) years (57.5% women) participated, including 14 with frailty and 26 with pre-frailty. In the first week follow-up, men had a significant increase in MT (0.9 mm [95%CI 0.3 to 1.4], p = 0.003) and CSA (0.4 cm² [95%CI 0.1 to 0.6], p = 0.007). During the second week, men continued to have a significant increase in MT (0.7 mm [95%CI 0.0 to 1.4], p = 0.036) and CSA (0.6 cm² [95%CI 0.01 to 1.2], p = 0.048). Patients with frailty had lower values of MT-RF and CSA-RF at admission and during the hospitalization period. A moderate-to-good correlation of MT-RF and CSA with handgrip strength, fat-free mass and gait speed was observed. Musculoskeletal ultrasound was able to detect MT-RF and CSA-RF changes in older adults admitted to a post-acute care unit.

Higher uric acid serum levels are associated with sarcopenia in west China: a cross-sectional study

Background

Sarcopenia is the decline in muscle strength and mass attributed to aging. The pathogenesis of sarcopenia may be triggered by oxidative stress and uric acid (UA) has strong antioxidant properties. The aim of this study was to investigate the relationship between UA and sarcopenia in community-dwelling adults of West China using the baseline data of West China Health and Aging Trend (WCHAT) study.

Design

A cross-sectional study.

Methods

4236 adults aged 50 years or older in communities of west China were enrolled in this study. We applied Asian Working Group for Sarcopenia (AWGS) 2019 criteria to define sarcopenia. Muscle mass was measured using skeletal muscle index (SMI) based on bioimpedance analysis (BIA). Handgrip strength (HGS) and gait speed (GS) were recorded, respectively. Different variables like anthropometry measures, life styles, chronic disease and blood test were collected. General linear model was done to investigate the relationship between UA and HGS/GS/SMI, adjusting age, ethnic groups, sleeping quality, education level, cognitive function, smoking history, drinking history, ADL score, and chronic disease.

Results

Participants were grouped according to UA quartiles by gender. After adjusting for potential confounders, a negative association between serum UA levels and sarcopenia was shown both in men and women. And a significant association between serum UA levels and HGS in women was shown as an inverted J shape. Besides, a positive association between the UA quartiles and SMI was observed, irrespective of gender.

Conclusions

Our results showed that higher uric acid levels were significantly correlated with higher muscle mass and grip strength among Chinese adults aged over 50. Higher UA serum levels might slow down the progression of sarcopenia.

Skeletal muscle atrophy: From mechanisms to treatments

Skeletal muscle is a crucial tissue for movement, gestural assistance, metabolic homeostasis, and thermogenesis. It makes up approximately 40% of the total body weight and 50% of total protein. However, several pathological abnormalities (e.g., chronic diseases, cancer, long-term infection, aging) can induce an imbalance in skeletal muscle protein synthesis and degradation, which triggers muscle wasting and even leads to atrophy. Skeletal muscle atrophy is characterized by weakening, shrinking, and decreasing muscle mass and fiber cross-sectional area at the histological level. It manifests as a reduction in force production, easy fatigue and decreased exercise capability, along with a lower quality of life. Mechanistically, there are several pathophysiological processes involved in skeletal muscle atrophy, including oxidative stress and inflammation, which then activate signal transduction, such as the ubiquitin proteasome system, autophagy lysosome system, and mTOR. Considering the great economic and social burden that muscle atrophy can inflict, effective prevention and treatment strategies are essential but still limited. Exercise is widely acknowledged as the most effective therapy for skeletal muscle atrophy; unfortunately, it is not applicable for all patients. Several active substances for skeletal muscle atrophy have been discovered and evaluated in clinical trials, however, they have not been marketed to date. Knowledge is being gained on the underlying mechanisms, highlighting more promising treatment strategies in the future. In this paper, the mechanisms and treatment strategies for skeletal muscle atrophy are briefly reviewed.

Emerging molecular mediators and targets for age-related skeletal muscle atrophy

The age-associated decline in muscle mass has become synonymous with physical frailty among the elderly due to its major contribution in reduced muscle function. Alterations in protein and redox homeostasis along with chronic inflammation, denervation, and hormonal dysregulation are all hallmarks of muscle wasting and lead to clinical sarcopenia in older adults. Reduction in skeletal muscle mass has been observed and reported in the scientific literature for nearly 2 centuries; however, identification and careful examination of molecular mediators of age-related muscle atrophy have only been possible for roughly 3 decades. Here we review molecular targets of recent interest in age-related muscle atrophy and briefly discuss emerging small molecule therapeutic treatments for muscle wasting in sarcopenic susceptible populations.

Redox modulation of muscle mass and function

Muscle mass and strength are very important for exercise performance. Training-induced musculoskeletal injuries usually require periods of complete immobilization to prevent any muscle contraction of the affected muscle groups. Disuse muscle wasting will likely affect every sport practitioner in his or her lifetime. Even short periods of disuse results in significant declines in muscle size, fiber cross sectional area, and strength. To understand the molecular signaling pathways involved in disuse muscle atrophy is of the utmost importance to develop more effective countermeasures in sport science research.

We have divided our review in four different sections. In the first one we discuss the molecular mechanisms involved in muscle atrophy including the main protein synthesis and protein breakdown signaling pathways. In the second section of the review we deal with the main cellular, animal, and human atrophy models. The sources of reactive oxygen species in disuse muscle atrophy and the mechanism through which they regulate protein synthesis and proteolysis are reviewed in the third section of this review. The last section is devoted to the potential interventions to prevent muscle disuse atrophy with especial consideration to studies on which the levels of endogenous antioxidants enzymes or dietary antioxidants have been tested.

Association between sarcopenia and rheumatological diseases

Sarcopenia (“sarx” for muscle, “penia” for loss) is an important problem in the elderly. Although muscle loss is a part of natural aging, excessive loss that limits physical activity is considered pathological. Sarcopenia is associated with age, malnutrition, physical inactivity, inflammatory stress and hormonal changes. Although relationships between sarcopenia and various chronic inflammatory diseases have been shown, the role of rheumatologic disease in sarcopenia development is currently unknown. Our aim in this mini-review was to increase the awareness of clinicians to sarcopenia, and to evaluate studies in which the relationship between sarcopenia and rheumatologic diseases was investigated. We also aimed to determine whether the available literature was sufficient to confirm a strong relationship between these conditions. Although our findings showed that diseases such as rheumatoid arthritis, osteoarthritis and systemic sclerosis may have a role in sarcopenia development and progress, the methodologies and results of the majority of studies were insufficient in determining direct causal relationships. We believe future studies would benefit from focusing on the factors and causes of sarcopenia, with a goal of determining the factors associated with rheumatologic disease that are most effective in sarcopenia development.

Evaluation of Oxidative Stress Parameters and Antioxidant Status in Plasma and Erythrocytes of Elderly Diabetic Patients with Sarcopenia

OBJECTIVES

Oxidative stress may play a role in the pathogenesis of both sarcopenia and diabetes. Although the risk of sarcopenia is increased in people with type 2 diabetes, the relationship between sarcopenia oxidative stress and antioxidant status among the older diabetes population is not well studied. The aim of this present study was to evaluate the relationship between oxidative stress and antioxidant status and sarcopenia in elderly diabetic patients.

DESIGN

This was a cross-sectional designed study with a control group. A total of 60 type 2 diabetic elderly patients were enrolled in the study (30 sarcopenic and 30 controls).

MEASUREMENTS

Comprehensive geriatric assessments and anthropometric measurements were performed. Sarcopenia was diagnosed according to the European Working Group on Sarcopenia in Older People. Skeletal muscle mass was measured using bioelectrical impedance analysis. A handheld dynamometer was used for skeletal muscle strength measurements. Gait speed was measured using a 4 meter walking test. Plasma malondialdehyde (MDA), glutathione peroxidase (GSH-Px) and erythrocyte MDA, GSH-Px, superoxide dismutase (SOD), catalase and xanthine oxidase (XO) measurements were performed.

RESULTS

While plasma XO was significantly higher in sarcopenic individuals (0.406(0.225-0.775)) compared to controls (0.312(0.112-0.712)) (p=0.006), plasma GSH-Px was significantly lower in sarcopenic individuals (0.154(0.101-0.274)) compared to controls (0.204(0.12-.0312)) (p=0.003). Plasma XO (OR: 2.69 (CI 95% 0.13-52.76, p=0.041) and BMI (OR: 0.6 (CI 95% 0.41-0.89, p=0.009) were independently associated with sarcopenia of diabetes in multivariate analysis.

CONCLUSIONS

Only plasma XO was found to be independently associated with sarcopenia. XO can be important in the pathogenesis of sarcopenia in diabetes. Oxidative stress and antioxidant status might be associated with sarcopenia in diabetic older individuals but this association seems to be mediated by other factors. Further studies are needed on this subject.