Relationship between human aging muscle and oxidative system pathway

Low dietary vitamin C intake is associated with low muscle strength among elderly Korean women

Although vitamin C is one of the most important antioxidants, its effect on muscle quality is not fully understood. Therefore, we hypothesized that low dietary vitamin C intake is associated with low muscle strength. To test the hypothesis, a single 24-h dietary recall and handgrip strength test of 10,883 younger adults 19-64 y and 3,961 older adults ≥65 y from the seventh Korea National Health and Examination Survey (KNHANES VII 2016-2018) was analyzed by multivariable linear and logistic regression models, and low muscle strength was defined as handgrip strength <28 kg for men and <18 kg for women. Approximately 15.5% of Korean adults met the recommended intake of dietary vitamin C, and those with higher dietary vitamin C intake had higher total energy and protein intake. After adjusting for confounding variables, including age, body mass index, total energy intake, household income, alcohol consumption, smoking, resistance exercise, medical condition, and dietary intake of protein, vitamin E, and β-carotene, dietary vitamin C was correlated with maximal handgrip strength in younger women 19-64 y (β = 0.002; SE = 0.001; P-value = .026) and older women ≥65 y (β = 0.005; SE = 0.002; P-value = .013). Among older women ≥65 y, those in the lowest quartile of dietary vitamin C intake had a higher risk of low muscle strength compared to those in the highest quartile after adjustment of confounding factors (odds ratio, 2.16; 95% confidence interval, 1.49-3.15). These results imply that adequate dietary vitamin C intake may reduce the risk of sarcopenia in older Korean women.

Relationship between serum uric acid and sarcopenia in geriatric heart failure patients with preserved ejection fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) presents a serious risk to human health. The increased prevalence of sarcopenia in the HFpEF population has a negative impact on patient prognosis. Uric acid (UA) is the byproduct of purine metabolism and is harmful to the cardiovascular system. This study aims to establish the potential relationship between sarcopenia and serum UA in HFpEF patients.

METHODS

Data were obtained from 180 individuals (aged ≥60 years) with HFpEF admitted to the Geriatric Department of Jiangsu Province Hospital between January 2021 and December 2022. The UA values were grouped into 4 quartiles (Q1-Q4). Logistic generalized linear models and restricted cubic spline (RCS) regression were used to analyze the relationship between sarcopenia and UA. Subgroups based on gender were utilised for further analysis.

RESULTS

After adjusting for covariates, odds ratios (ORs) and 95 % confidence intervals (CIs) for sarcopenia prevalence in the 2nd, 3rd, and 4th quartiles were 2.56 (0.57-12.65), 4.94 (1.10-24.49), and 6.95 (1.30-44.25), respectively, unlike the 1st quartile (P for trend = 0.022). The RCS plot demonstrated a positive linear relationship between serum UA levels and sarcopenia (P for non-linearity = 0.190). A sex-based subgroup analysis revealed a statistically significant relationship between UA and sarcopenia in males (P < 0.05).

CONCLUSIONS

In summary, the prevalence of sarcopenia is positively related to serum UA levels among the elderly diagnosed with HFpEF. Due to the cross-sectional nature of the study design, additional investigations are necessary to validate our findings and identify the optimal range for UA reduction.

Mitochondrial involvement in sarcopenia

Sarcopenia lowers the quality-of-life for millions of people across the world, as accelerated loss of skeletal muscle mass and function contributes to both age- and disease-related frailty. Physical activity remains the only proven therapy for sarcopenia to date, but alternatives are much sought after to manage this progressive muscle disorder in individuals who are unable to exercise. Mitochondria have been widely implicated in the etiology of sarcopenia and are increasingly suggested as attractive therapeutic targets to help restore the perturbed balance between protein synthesis and breakdown that underpins skeletal muscle atrophy. Reviewing current literature, we note that mitochondrial bioenergetic changes in sarcopenia are generally interpreted as intrinsic dysfunction that renders muscle cells incapable of making sufficient ATP to fuel protein synthesis. Based on the reported mitochondrial effects of therapeutic interventions, however, we argue that the observed bioenergetic changes may instead reflect an adaptation to pathologically decreased energy expenditure in sarcopenic muscle. Discrimination between these mechanistic possibilities will be crucial for improving the management of sarcopenia.

The contribution of mitochondria to age-related skeletal muscle wasting: A sex-specific perspective

As people age, their skeletal muscle (SkM) experiences a decline in mitochondrial functionality and density, which leads to decreased energy production and increased generation of reactive oxygen species. This cascade of events, in turn, might determine the loss of SkM mass, strength and quality. Even though the mitochondrial processes dysregulated by aging, such as oxidative phosphorylation, mitophagy, antioxidant defenses and mtDNA transcription, are the same in both sexes, mitochondria age differently in the SkM of men and women. Indeed, the onset and magnitude of the impairment of these processes seem to be influenced by sex-specific factors. Sexual hormones play a pivotal role in the regulation of SkM mass through both genomic and non-genomic mechanisms. However, the precise mechanisms by which these hormones regulate mitochondrial plasticity in SkM are not fully understood. Although the presence of estrogen receptors in mitochondria is recognized, it remains unclear whether androgen receptors affect mitochondrial function. This comprehensive review critically dissects the current knowledge on the interplay of sex in the aging of SkM, focusing on the role of sex hormones and the corresponding signaling pathways in shaping mitochondrial plasticity. Improved knowledge on the sex dimorphism of mitochondrial aging may lead to sex-tailored interventions that target mitochondrial health, which could be effective in slowing or preventing age-related muscle loss.

Effect of non-pharmacological interventions on the prevention of sarcopenia in menopausal women: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Sarcopenia is a chronic disease marked by gradual muscle system and functional decline. Prior research indicates its prevalence in those under 60 varies from 8 to 36%. There is limited evidence on the effectiveness of non-pharmacological interventions for sarcopenia prevention in menopausal women aged 40-60. This study examines the influence of such interventions for sarcopenia prevention on these women.

METHODS

PubMed, EMBASE, Medline, Cochrane Library, CINAHL, PEDro, and Airiti Library were searched from inception until May 5, 2023. Randomized controlled trials that examined exercise, vitamin D and protein supplementation effects on muscle mass, strength, and physical function. Quality assessment used the Cochrane risk of bias tool, and analysis employed Comprehensive Meta-Analysis version 2.0.

RESULTS

A total of 27 randomized controlled trials, involving 1,989 participants were identified. Meta-analysis results showed exercise improved lean body mass (SMD = 0.232, 95% CI: 0.097, 0.366), handgrip strength (SMD = 0.901, 95% CI: 0.362, 1.441), knee extension strength (SMD = 0.698, 95% CI: 0.384, 1.013). Resistance training had a small effect on lean body mass, longer exercise duration (> 12 weeks) and higher frequency (60-90 min, 3 sessions/week) showed small to moderate effects on lean body mass. Vitamin D supplementation improved handgrip strength (SMD = 0.303, 95% CI: 0.130, 0.476), but not knee extension strength. There was insufficient data to assess the impact of protein supplementation on muscle strength.

CONCLUSIONS

Exercise effectively improves muscle mass, and strength in menopausal women. Resistance training with 3 sessions per week, lasting 20-90 min for at least 6 weeks, is most effective. Vitamin D supplementation enhances small muscle group strength. Further trials are needed to assess the effects of vitamin D and protein supplementation on sarcopenia prevention.

REGISTRATION NUMBER

This review was registered on PROSPERO CRD42022329273.

The Implication of Nutrition on the Prevention and Improvement of Age-Related Sarcopenic Obesity: A Systematic Review

OBJECTIVES

Nutrition plays a pivotal role in the initiation and progression of sarcopenic obesity, making it a critical focus for preventing and treating this condition. However, the specific dietary components that effectively combat sarcopenic obesity remain poorly understood. The objective of this systematic review was to examine the potential nutritional and dietary factors that may play a role in the development of sarcopenic obesity in the elderly population.

METHODS

To identify relevant studies investigating the association/effects of dietary pattern/single foods/nutrients or supplements with sarcopenic obesity-related outcomes, a comprehensive literature search was conducted until April 2023. The search encompassed multiple databases including PubMed, Scopus, EMBASE, and Google Scholar. Two researchers performed rigorous assessments that included screening titles and abstracts, reviewing full-text studies, extracting data, and evaluating the quality of the studies. The Newcastle-Ottawa Scale was used for observational studies, while the Jadad-Oxford Scale was employed for clinical trials.

RESULTS

Twenty-three studies (14 observational studies and 9 trials) with 37078 participants, published between 2012 and 2022, were eligible for the systematic review. Of the 14 observational articles, two focused on dietary patterns and 12 on food/calorie/macro- and micronutrient intake. The nutritional interventions included the intake of supplements (i.e., protein, amino acids, tea catechin, and vitamin D) and dietary management (calorie restriction, very low-calorie ketogenic diet, and high-protein diet). Appropriate dietary factors, such as appropriate intake of calories, macronutrients, micronutrients, antioxidant nutrients, vegetables, fruits, and overall dietary quality, have been shown to be effective in preventing and treating sarcopenic obesity-related parameters. A combined approach of hypocaloric diet and high protein intake may be necessary for managing both obesity and sarcopenia in older individuals.

CONCLUSION

Studies suggest that dietary factors, such as overall dietary quality, appropriate intake of calories and protein, consumption of antioxidant nutrients, vegetables, fruits, and protein, may be linked to sarcopenic obesity.

The Association of Circulating Amino Acids and Dietary Inflammatory Potential with Muscle Health in Chinese Community-Dwelling Older People

Amino acids (AAs) and dietary inflammatory potential play essential roles in muscle health. We examined the associations of dietary inflammatory index (DII) of habitual diet with serum AA profile, and ascertained if the associations between DII and muscle outcomes were mediated by serum AAs, in 2994 older Chinese community-dwelling men and women (mean age 72 years) in Hong Kong. Higher serum branched chain AAs (BCAAs), aromatic AAs and total glutathione (tGSH) were generally associated with better muscle status at baseline. A more pro-inflammatory diet, correlating with higher serum total homocysteine and cystathionine, was directly (90.2%) and indirectly (9.8%) through lower tGSH associated with 4-year decline in hand grip strength in men. Higher tGSH was associated with favorable 4-year changes in hand grip strength, gait speed and time needed for 5-time chair stands in men and 4-year change in muscle mass in women. Higher leucine and isoleucine were associated with decreased risk of sarcopenia in men; the associations were abolished after adjustment for BMI. In older men, perturbations in serum sulfur AAs metabolism may be biomarkers of DII related adverse muscle status, while the lower risk of sarcopenia with higher BCAAs may partly be due to preserved BMI.

Sarcopenia, a major clinical problem in old age, potential causes, clinical consequences and therapeutic possibilities

Sarcopenia or degeneration of skeletal muscle tissue with aging, is responsible for functional de-cline and loss of independence in older adults. The purpose of this article is to review the current definitions of sarcopenia, its potential causes, clinical consequences and the potential for prop-hylactic and curative intervention. Sarcopenia is recognized as a major clinical problem for the elderly, and the research in this area is growing exponentially. One of the most important recent developments has been convergence in the operational definition of sarcopenia that combines muscle mass, strength and muscle function. In 2010, the European Working Group on Sarcopenia in Oder People (EWGSOP) published a definition of sarcopenia aimed at promoting progress in the identification and care of the elderly. In early 2018 (EWGSOP2) he met again to update the original definition to reflect the scientific and clinical evidence that has been built over the past decade. The cause of sarcopenia is considered to be multifactorial: hormonal changes, neurologi-cal decline, sedentary / immobilization for a long period, chronic diseases, obesity, all these fac-tors contribute to the onset of sarcopenia. Prophylactic or curative interventions are essentially aimed at nutrition and exercise. Although pharmaceutical agents are developed that target seve-ral biological pathways, proper nutrition and specific physical exercises remain the gold stan-dard for therapy. Through this review, we want to draw attention to the need to implement complex analyzes of the elderly patient, regardless of the acute problem with which he presents himself at the consultation. These analyses should contain tests, measurements, questionnaires that identify in time a possible musculoskeletal degeneration. The results did not show any sig-nificant difference between the perception of sarcopenia, the way of approaching it and the prophylactic or therapeutic treatment. We focused on this pathology because sarcopenia is rela-tively newly observed, defined, it is not fully investigated and a clinical skill has not been for-med for the evaluation of the elderly patient. Keywords: Skeletal muscle, elderly, sarcopenia, degeneration, exercises

Mitochondrial ion channels in aging and related diseases

Transport of materials and information across cellular boundaries, such as plasma, mitochondrial and nuclear membranes, happens mainly through varieties of ion channels and pumps. Various biophysical and biochemical processes play vital roles. The underlying mechanisms and associated phenomenological lipid membrane transports are linked directly or indirectly to the cell health condition. Mitochondrial membranes (mitochondrial outer membrane (MOM) and mitochondrial inner membrane (MIM)) host crucial cellular processes. Their malfunction is often found responsible for the rise of cell-originated diseases, including cancer, Alzheimer's, neurodegenerative disease, etc. A large number of ion channels active across MOM and MIM are known to belong to vital cell-based structures found to be linked directly to cellular signaling. Hence their malfunctions are often found to contribute to abnormalities in intracellular communication, which may even be associated with the rise of various diseases. In this article, the aim is to pinpoint ion channels that are directly or indirectly linked to especially aging and related abnormalities in health conditions. An attempt has been made to address the natural structures of these channels, their mutated conditions, and the ways we may cause interventions in their malfunctioning. The malfunction of ion channel subunits, including especially various proteins, involved directly in channel formation and/or indirectly in channel stabilization, leads to the rise of various channel-specific diseases, which are known as channelopathies. Channelopathies in aging will be discussed briefly. This mini-review may be found as an important reference for drug discovery scientists dealing with aging-related diseases.

Major dietary patterns in relation to muscle strength status among middle-aged people: A cross-sectional study within the RaNCD cohort

Grip strength in midlife can predict physical disability in senior years. Recent evidence shows the critical role of nutritional status on muscle function. We aimed to elucidate whether adherence to a particular dietary pattern would be associated with abnormal muscle strength among middle-aged people. In this cross-sectional study, a semiquantitative Food Frequency Questionnaire was used to assess the dietary intake of 2781 participants in the Ravansar Non-Communicable Chronic Disease (RaNCD) cohort. Major dietary patterns from 28 main food groups were extracted using principal component analysis. Binary logistic regression was used to determine the association between the tertiles of the major dietary patterns and muscle strength status. Two major dietary patterns were identified: the "mixed dietary pattern" that heavily loaded with fruits, vegetables, nuts, dairies, sweets, legumes, dried fruits, fish, red meat, butter, whole grains, natural juices, poultry, pickles, olive, industrial juice, egg, processed meat, and snacks and "unhealthy dietary pattern" that heavily loaded by fats, sugar, refined grains, soft drink, salt, organ meat, tea, and coffee. Adherence to the mixed dietary pattern (OR = 1.03, 95% CI = 0.8-1.33, P for trend = 0.77) and the unhealthy dietary pattern (OR = 1.01, 95% CI = 0.79-0.13, P for trend = 0.89) did not associate with abnormal muscle strength. This study suggests that the dietary pattern involving the consumption of healthy and unhealthy food does not have an effect on muscle strength in middle-aged adults.

Redox Responsive Copolyoxalate Smart Polymers for Inflammation and Other Aging-Associated Diseases

Polyoxalate (POx) and copolyoxalate (CPOx) smart polymers are topics of interest the field of inflammation. This is due to their drug delivery ability and their potential to target reactive oxygen species (ROS) and to accommodate small molecules such as curcumin, vanilline, and p-Hydroxybenzyl alcohol. Their biocompatibility, ultra-size tunable characteristics and bioimaging features are remarkable. In this review we discuss the genesis and concept of oxylate smart polymer-based particles and a few innovative systemic delivery methods that is designed to counteract the inflammation and other aging-associated diseases (AADs). First, we introduce the ROS and its role in human physiology. Second, we discuss the polymers and methods of incorporating small molecule in oxalate backbone and its drug delivery application. Finally, we revealed some novel proof of concepts which were proven effective in disease models and discussed the challenges of oxylate polymers.

Identification of a Sesquiterpene Lactone from Arctium lappa Leaves with Antioxidant Activity in Primary Human Muscle Cells

Many pathologies affecting muscles (muscular dystrophies, sarcopenia, cachexia, renal insufficiency, obesity, diabetes type 2, etc.) are now clearly linked to mechanisms involving oxidative stress. In this context, there is a growing interest in exploring plants to find new natural antioxidants to prevent the appearance and the development of these muscle disorders. In this study, we investigated the antioxidant properties of Arctium lappa leaves in a model of primary human muscle cells exposed to H₂O₂ oxidative stress. We identified using bioassay-guided purification, onopordopicrin, a sesquiterpene lactone as the main molecule responsible for the antioxidant activity of A. lappa leaf extract. According to our findings, onopordopicrin inhibited the H₂O₂-mediated loss of muscle cell viability, by limiting the production of free radicals and abolishing DNA cellular damages. Moreover, we showed that onopordopicrin promoted the expression of the nuclear factor-erythroid-2-related factor 2 (Nrf2) downstream target protein heme oxygenase-1 (HO-1) in muscle cells. By using siRNA, we demonstrated that the inhibition of the expression of Nrf2 reduced the protective effect of onopordopicrin, indicating that the activation of the Nrf2/HO-1 signaling pathway mediates the antioxidant effect of onopordopicrin in primary human muscle cells. Therefore, our results suggest that onopordopicrin may be a potential therapeutic molecule to fight against oxidative stress in pathological specific muscle disorders.

Flow-mediated outward arterial remodeling in aging

The present review focuses on the effect of aging on flow-mediated outward remodeling (FMR) via alterations in estrogen metabolism, oxidative stress and inflammation. In ischemic disorders, the ability of the vasculature to adapt or remodel determines the quality of the recovery. FMR, which has a key role in revascularization, is a complex phenomenon that recruits endothelial and smooth muscle cells as well as the immune system. FMR becomes progressively less with age as a result of an increase in inflammation and oxidative stress, in part of mitochondrial origin. The alteration in FMR is greater in older individuals with risk factors and thus the therapy cannot merely amount to exercise with or without a mild vasodilating drug. Interestingly, the reduction in FMR occurs later in females. Estrogen and its alpha receptor (ERα) play a key role in FMR through the control of dilatory pathways including the angiotensin II type 2 receptor, thus providing possible tools to activate FMR in older subjects although only experimental data is available. Indeed, the main issue is the reversibility of the vascular damage induced over time, and to date promoting prevention and limiting exposure to the risk factors remain the best options in this regard.

Fruit and vegetable intake and risk of frailty in women 60 years old or older

BACKGROUND

Prior research has suggested that the antioxidative and anti-inflammatory potential of fruits and vegetables may ameliorate aging-related frailty.

OBJECTIVE

We sought to prospectively examine the association between fruit and vegetable intake and incident frailty in older women.

DESIGN

We followed 78,366 nonfrail women aged ≥60 y from the Nurses' Health Study from 1990 to 2014. In this analysis, the primary exposure was the intake of total fruits and vegetables, assessed with an FFQ administered 6 times during follow-up. Frailty was defined as having ≥3 of the following 5 criteria from the FRAIL scale: fatigue, poor strength, low aerobic capacity, having ≥5 illnesses, and ≥5% weight loss. Cox models adjusted for potential confounders were used to estimate HRs and 95% CIs for the association between fruit and vegetable intake and incident frailty.

RESULTS

In total, 12,434 (15.9%) incident frailty cases were accrued during follow-up. Total fruit and vegetable intakes were associated with a lower risk of frailty (adjusted HR comparing 7+ servings/d compared with <3 servings/d: 0.92; 95% CI: 0.85, 0.99). The inverse association appeared to be stronger for those with physical activity above the median (P-interaction < 0.05). Among physically active women, compared with those who consumed <3 servings/d, the HR for 7+ servings/d was 0.68 (95% CI: 0.57, 0.81).

CONCLUSION

Higher fruit and vegetable intake was associated with a lower risk of frailty in this cohort of US women aged ≥60 y. Because of limited evidence on intakes of fruits and vegetables and the development of frailty, more data are needed to confirm our results.

Prospective Associations Between Dietary Antioxidant Intake and Frailty in Older Australian Men: The Concord Health and Ageing in Men Project

BACKGROUND

The objective of the study is to evaluate the prospective associations between antioxidant intake and incident frailty among older Australian men aged ≥75 years.

METHODS

Seven hundred and ninety-four men participated in a detailed diet history interview at the Concord Health and Ageing in Men Project (CHAMP) study third wave (considered baseline nutrition here) and 781 men participated at the fourth wave (considered 3-year follow-up here). The main outcome measurement was incident frailty at 3-year follow-up, using the Cardiovascular Health Study definition. Dietary adequacy of antioxidant intake was assessed by comparing participants' median intakes of four dietary antioxidants (vitamin A, E, C, and zinc) to the nutrient reference values (NRVs). Attainment of the NRVs was incorporated into a dichotomized variable "poor" (meeting ≤2 antioxidants) or "good" (meeting ≥3 antioxidants) as the independent variable using the cut-point method. Also, intakes of each individual dietary antioxidant at baseline nutrition were categorized into quartiles. Analyses were performed using multinomial logistic regression.

RESULTS

Incidence of pre-frailty was 53.0% and frailty was 6.4% at 3-year follow-up. Poor dietary antioxidant intake (meeting ≤2) at baseline nutrition was associated with incident frailty at 3-year follow-up in unadjusted (OR: 2.59 [95% CI: 1.47, 4.59, p = .001]) and adjusted (OR: 2.46 [95% CI: 1.10, 5.51, p = .03]) analyses. The lowest quartile of vitamin E intake (<7.08 mg/d) was significantly associated with incident frailty (OR: 2.46 [95% CI: 1.01, 6.00, p = .05]).

CONCLUSIONS

Poor antioxidant intake, particularly vitamin E, is a plausible factor associated with incident frailty among older men. This supports the need for clinical trials of diets rich in antioxidants or possibly low-dose antioxidant supplements, for prevention of frailty.

Total Dietary Antioxidant Capacity and Longitudinal Trajectories of Body Composition

Although there is some evidence that total dietary antioxidant capacity (TDAC) is inversely associated with the presence of obesity, no longitudinal studies have been performed investigating the effect of TDAC on comprehensive measures of body composition over time. In this study, we included 4595 middle-aged and elderly participants from the Rotterdam Study, a population-based cohort. We estimated TDAC among these individuals by calculating a ferric reducing ability of plasma (FRAP) score based on data from food-frequency questionnaires. Body composition was assessed by means of dual X-ray absorptiometry at baseline and every subsequent 3–5 years. From these data, we calculated fat mass index (FMI), fat-free mass index (FFMI), android-to-gynoid fat ratio (AGR), body fat percentage (BF%) and body mass index (BMI). We also assessed hand grip strength at two time points and prevalence of sarcopenia at one time point in a subset of participants. Data were analyzed using linear mixed models or multinomial logistic regression models with multivariable adjustment. We found that higher FRAP score was associated with higher FFMI (0.091 kg/m² per standard deviation (SD) higher FRAP score, 95% CI 0.031; 0.150), lower AGR (−0.028, 95% CI −0.053; −0.003), higher BMI (0.115, 95% CI 0.020; 0.209) and lower BF% (−0.223, 95% CI −0.383; −0.064) across follow-up after multivariable adjustment. FRAP score was not associated with hand grip strength or sarcopenia. Additional adjustment for adherence to dietary guidelines and exclusion of individuals with comorbid disease at baseline did not change our results. In conclusion, dietary intake of antioxidants may positively affect the amount of lean mass and overall body composition among the middle-aged and elderly.

Robustness during Aging-Molecular Biological and Physiological Aspects

Understanding the process of aging is still an important challenge to enable healthy aging and to prevent age-related diseases. Most studies in age research investigate the decline in organ functionality and gene activity with age. The focus on decline can even be considered a paradigm in that field. However, there are certain aspects that remain surprisingly stable and keep the organism robust. Here, we present and discuss various properties of robust behavior during human and animal aging, including physiological and molecular biological features, such as the hematocrit, body temperature, immunity against infectious diseases and others. We examine, in the context of robustness, the different theories of how aging occurs. We regard the role of aging in the light of evolution.

Aging Fits the Disease Criteria of the International Classification of Diseases

The disease criteria used by the World Health Organization (WHO) were applied to human biological aging in order to assess whether aging can be classified as a disease. These criteria were developed for the 11th revision of the International Classification of Diseases (ICD) and included disease diagnostics, mechanisms, course and outcomes, known interventions, and linkage to genetic and environmental factors. RESULTS: Biological aging can be diagnosed with frailty indices, functional, blood-based biomarkers. A number of major causal mechanisms of human aging involved in various organs have been described, such as inflammation, replicative cellular senescence, immune senescence, proteostasis failures, mitochondrial dysfunctions, fibrotic propensity, hormonal aging, body composition changes, etc. We identified a number of clinically proven interventions, as well as genetic and environmental factors of aging. Therefore, aging fits the ICD-11 criteria and can be considered a disease. Our proposal was submitted to the ICD-11 Joint Task force, and this led to the inclusion of the extension code for "Ageing-related" (XT9T) into the "Causality" section of the ICD-11. This might lead to greater focus on biological aging in global health policy and might provide for more opportunities for the new therapy developers.

Tannase-Converted Green Tea Extract with High (-)-Epicatechin Inhibits Skeletal Muscle Mass in Aged Mice

The objective of this study was to investigate the effects of tannase-converted green tea extract on body composition, muscle oxidative stress-related factors, and differentiation-related factors. The mean bone-related parameters and body composition were determined by the live dual-energy X-ray absorptiometry (DEXA). Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used to determine mRNA expression and protein levels, respectively. The results of total mass testing in the epicatechin control (EC) and middle concentration tannase-converted green tea extract (T₁) intake groups were not significantly different compared with those in the control group; however, the high-concentration tannase-converted green tea extract (T₂) group showed a significantly higher effect to the lean than that of all other groups (p < 0.05). The results of the assay of muscle differentiation-related genes indicated that the expression levels in the EC and T₁ groups (p < 0.05) and the expression levels in the T₂ group (p < 0.01) were significantly different in the bicep femoris compared with that in the control group. The results of the SOD gene assay indicate that the expression levels in the EC and T₁ groups (p < 0.05) and the expression level in the T₂ group (p < 0.01) were significantly different in the bicep femoris compared with that in the control group. Additionally, SOD gene expression in the T₂ group was significantly increased (p < 0.05) in the soleus compared with that in the control, EC and T₁ groups. Our results suggest that tannase-converted green tea extract prevents muscle loss and regulates the quantity and quality of muscle by the levels of antioxidant stress-related enzymes and muscle differentiation factors to a greater extent than the administration of epicatechin and middle dose green tea extract.

Sarcopenia in relation to nutrition and lifestyle factors among middle-aged and older Korean adults with obesity

PURPOSE

To examine the prevalence of sarcopenic obesity (SO) and its association with nutrition and lifestyle factors.

METHODS

Data from the 2008-2011 Korea National Health and Nutrition Examination Survey for 3937 Korean individuals aged 40 years or older with obesity defined by the modified Asia-Pacific criteria (BMI ≥ 25 kg/m²) were used. Sarcopenia was defined as an appendicular skeletal muscle mass divided by weight (%) of < 1 SD below the sex-specific mean for young adults. Logistic regression models were used for the associations controlling covariates.

RESULTS

The prevalence of SO was 52.5%. The SO group had insufficient energy intake, protein, and antioxidant micronutrients, a lower overall dietary quality, a lower physical activity, and higher rates of negative psychological factors than the non-sarcopenic obesity group (p < 0.05). After controlling for covariates, having high mean adequacy ratio scores which was calculated by averaging the sum of the nutrient adequacy ratios had a 94% lower prevalence of SO in the older individuals. Low participation in aerobic exercises had a 74% higher prevalence of SO in the older aged group, and high participation in flexibility exercises had a 11% lower prevalence of SO in the middle-aged group. Interestingly, negative psychological factors were found only in the middle-aged adults with SO (p < 0.05).

CONCLUSION

Sarcopenia was present in over half of the middle-aged and older Korean adults with obesity. Having high dietary quality, increased physical activity, and positive psychological health were associated with a low prevalence of SO.

The Role of Nutrition in Attenuating Age-Related Skeletal Muscle Atrophy

The elderly population is increasing rapidly worldwide, and we are faced with the significant challenge for maintaining or improving physical activity, independence, and quality of life. Sarcopenia, the age-related decline of skeletal muscle mass, is characterized by loss of muscle quantity and quality resulting to a gradual slowing of movement, a decrease in strength and power, elevated risk of fall-related injury, and often frailty. Supplemental, hormonal, and pharmacological approaches have been attempted to attenuate sarcopenia but these have not achieved outstanding results. In this review, we summarize the current knowledge of nutrition-based therapies for counteracting sarcopenia.

Changes and Risk Factors of Skeletal Muscle Mass and Strength in Patients with Type 2 Diabetes over 60 Years Old: A Cross-Sectional Study from China

OBJECTIVE

The accelerate loss of skeletal muscle mass, strength, and function, named sarcopenia, is a progressive and generalised skeletal muscle disorder, and it is always associated with increased outcomes including falls, frailty, and disability. Diabetes mellitus is associated with significant muscle and physical complications. We aimed at clarifying the changes and risk factors of skeletal muscle mass and strength in elderly with type 2 diabetes.

METHODS

The study consisted of patients with type 2 diabetes (n = 120) and an older general population (n = 126). The skeletal muscle mass and muscle strength, as well as the serum levels of chronic inflammation, oxidative stress, homocysteine, and insulin-like factor-1 were assessed, and the correlation and regression analysis were conducted to evaluate outcomes.

RESULTS

T2DM patients exhibited lower muscle strength compared with the non-T2DM subjects (P < 0.01). Among T2DM patients, serum IGF-1 levels were positively correlated with muscle strength (r = 0.255, P < 0.01) and muscle mass (r = 0.209, P < 0.05), levels of 8-OHdG were inversely correlated with muscle strength (r = -0.252, P < 0.01), and there was a negative association between HCY and muscle mass (r = -0.185, P < 0.05). Muscle mass and strength of patients with higher education level were significantly higher than those with lower education level (P < 0.05), in male patients, muscle mass and muscle strength were significantly lower in smokers (P < 0.01), and muscle mass was lower in chronic drinkers (P < 0.05).

CONCLUSIONS

These findings suggest that diabetic patients may be more susceptible to sarcopenia at an older age. And it also provides evidences that among elderly with diabetes mellitus, oxidative damage and HCY as well as IGF-1 are important predictors of age-dependent sarcopenia.

Neuromuscular Electrical Stimulation Induces Skeletal Muscle Fiber Remodeling and Specific Gene Expression Profile in Healthy Elderly

Skeletal muscle aging is a multifactorial process strictly related to progressive weakness. One of the results that were focused on was the fiber phenotype modification and their loss. The physiological muscle recruitment to contraction, basically prosecuted under volitional control, can also be engaged by means of Neuromuscular Electrical Stimulation (NMES). Knowing that the NMES is effective in improving muscle strength in active healthy elderly, the aim was to investigate which physiological modifications were able to produce in the Vastus lateralis muscle and the pathways involved. It was found that NMES increased the cross sectional area and the isometric strength of type II myofibers together with the activated myogenic pathway in order to shift glycolytic toward the oxidative phenotype II myofibers, at a molecular level and with an increase of maximal voluntary contraction (MVC) at a functional level. Using the TaqMan low density array on 48 different genes, we found that NMES specific gene regulation highlighted: (i) increased protein synthesis with respect to protein degradation; (ii) the activation of an apoptotic pathway involved in the differentiation process; (iii) increased regeneration signals; (iv) oxidative enzyme regulation. These pathways were validated via confirmatory RT-PCR for genes involved in the regeneration process as well as Myosin isoforms. We also investigated the oxidative stress status analyzing superoxide anion levels, the protein expression of two different superoxide dismutase and the activity of both catalase and superoxide anion dismutase, being two main antioxidant enzymes. In conclusion, data demonstrates that NMES is effective in producing physiological adaptation on Vastus Lateralis of active healthy elderly as well as providing new insights for further research on elderly who experienced muscle detriment for periodic or permanent immobility.

Furanocoumarins from the Roots of Angelica dahurica with Inhibitory Activity against Intracellular Reactive Oxygen Species Accumulation

Five new furanocoumarins, dahuribirin H (1), dahuribirin I (2), (2'S)-(+)-5-(2'-hydroxy-3'-methylbut-3'-enyloxy)-8-(3''-methylbut-2″-enyloxy)psoralen (3), (2'R)-(+)-5-(2',3'-epoxy-3'-methylbutoxy)-8-(3″-methylbut-2″-enyloxy)psoralen (4), and 5-methoxy-8-((Z)-4'-(3″-methylbutanoate)-3'-methylbut-2'-enyloxy)psoralen (5), along with 15 known compounds (6-20), were isolated from the roots of Angelica dahurica. The structures of the new compounds were elucidated by spectroscopic analysis, along with electronic circular dichroism calculations and Mosher ester analysis. Compounds 3, 4, 11, 13, and 16 reduced H₂O₂-induced cell death in HepG2 cells and attenuated reactive oxygen species (ROS) formation without showing cytotoxicity, suggesting that these compounds might have cytoprotective effects against H₂O₂-induced oxidative damage via ROS scavenging activities.

Skeletal Muscle Cell Oxidative Stress as a Possible Therapeutic Target in a Denervation-Induced Experimental Sarcopenic Model

STUDY DESIGN

A basic study using a rodent model of sarcopenia.

OBJECTIVE

To elucidate the contribution of oxidative stress to muscle degeneration and the efficacy of antioxidant treatment for sarcopenia using an animal model of neurogenic sarcopenia.

SUMMARY OF BACKGROUND DATA

Oxidative stress has been reported to be involved in a number of pathologies, including musculoskeletal disorders. Its relationship with sarcopenia, one of the potential origins of lower back pain, however, is not yet fully understood.

METHODS

Myoblast cell lines (C2C12) were treated with H2O2, an oxidative stress inducer, and N-acetyl-L-cysteine (NAC), an antioxidant. Apoptotic effects induced by oxidative stress and the antioxidant effects of NAC were assessed by western blotting, immunocytochemistry, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assays. An animal model of sarcopenia was produced via axotomy of the sciatic nerves to induce muscle atrophy. Twenty-four male Sprague-Dawley rats were divided into sham, sham+NAC, axotomy, and axotomy+NAC groups. Rats were provided water only or water containing NAC (1 g/L) for 4 weeks. The gastrocnemius muscle was isolated and stained with hematoxylin and eosin (H&E) 2 weeks after axotomy, from which muscle cells were harvested and protein extracted for evaluation.

RESULTS

Mitogen-activated protein kinases (MAPKs) were significantly activated by H2O2 treatment in C2C12 cells, which was ameliorated by NAC pretreatment. Furthermore, H2O2 induced apoptosis and death of C2C12 cells, which was prevented by NAC pretreatment. The weight of the gastrocnemius muscle was reduced in the axotomy group, which was prevented by NAC administration. Lastly, although muscle specimens from the axotomy group showed greater reductions in muscle fiber, the oral administration of NAC significantly inhibited amyotrophy via antioxidant effects.

CONCLUSION

The current in vitro and in vivo study demonstrated the possible involvement of oxidative stress in sarcopenic pathology. NAC represents a potential anti-sarcopenic drug candidate, preventing amyotrophy and fatty degeneration.

LEVEL OF EVIDENCE

4.

The effects of inflammation, aging and oxidative stress on the pathogenesis of diabetes mellitus (type 2 diabetes)

Diabetes mellitus is seen to be prevalent among the different epidemics. The prevalence rate of the diabetes mellitus is seen to be increasing in different regions of the world. Type 2 diabetes mellitus is the most common form of the disease that causes the defect in the production of insulin. It is associated with the disruption in the metabolism of fat, proteins and carbohydrates. Different complications that are associated with T2DM includes the retinopathy, neuropathy, nephropathy and weakness and other issues. Due to the loss of the function of the insulin, the metabolism is disturbed. . It is needed to consider the effects of inflammation aging and the oxidative stress on the diabetes mellitus. Therefore this review has dealt with this particular issue in great detail. The predominant aim of this review was to evaluate the effects of inflammation aging and oxidative stress on the T2DM. It was achieved through correlating and comparing the studies of different researchers. This review article has reviewed this topic in great detail considering the different researches related to the inflammation aging, oxidative stress and their impact on the diabetes mellitus.

Relationships Between Ion Channels, Mitochondrial Functions and Inflammation in Human Aging

Aging is often associated with a loss of function. We believe aging to be more an adaptation to the various, and often continuous, stressors encountered during life in order to maintain overall functionality of the systems. The maladaptation of a system during aging may increase the susceptibility to diseases. There are basic cellular functions that may influence and/or are influenced by aging. Mitochondrial function is amongst these. Their presence in almost all cell types makes of these valuable targets for interventions to slow down or even reserve signs of aging. In this review, the role of mitochondria and essential physiological regulators of mitochondria and cellular functions, ion channels, will be discussed in the context of human aging. The origins of inflamm-aging, associated with poor clinical outcomes, will be linked to mitochondria and ion channel biology.

Markers of Accelerated Skeletal Muscle Regenerative Response in Murphy Roths Large Mice: Characteristics of Muscle Progenitor Cells and Circulating Factors

The "super-healing" Murphy Roths Large (MRL/MpJ) mouse possesses a superior regenerative capacity for repair of many tissues, which makes it an excellent animal model for studying molecular and cellular mechanisms during tissue regeneration. As the role of muscle progenitor cells (MPCs) in muscle-healing capacity of MRL/MpJ mice has not been previously studied, we investigated the muscle regenerative capacity of MRL/MpJ mice following muscle injury, and the results were compared to results from C57BL/6J (B6) age-matched control mice. Our results show that muscle healing upon cardiotoxin injury was accelerated in MRL/MpJ mice and characterized by reduced necrotic muscle area, reduced macrophage infiltration, and more regenerated myofibers (embryonic myosin heavy chain+/centronucleated fibers) at 3, 5, and 12 days postinjury, when compared to B6 age-matched control mice. These observations were associated with enhanced function of MPCs, including improved cell proliferation, differentiation, and resistance to stress, as well as increased muscle regenerative potential when compared to B6 MPCs. Mass spectrometry of serum proteins revealed higher levels of circulating antioxidants in MRL/MpJ mice when compared to B6 mice. Indeed, we found relatively higher gene expression of superoxide dismutase 1 (Sod1) and catalase (Cat) in MRL/MpJ MPCs. Depletion of Sod1 or Cat by small interfering RNA impaired myogenic potential of MRL/MpJ MPCs, indicating a role for these antioxidants in muscle repair. Taken together, these findings provide evidence that improved function of MPCs and higher levels of circulating antioxidants play important roles in accelerating muscle-healing capacity of MRL/MpJ mice. Stem Cells 2019;37:357-367.

Higher Serum Uric Acid is a Risk Factor of Reduced Muscle Mass in Men with Type 2 Diabetes Mellitus

OBJECTIVE

Sarcopenia has been recognized as a diabetic complication, and hyperuricemia is often accompanied by type 2 diabetes mellitus (T2DM). However, it is unknown whether serum uric acid (UA) levels are associated with reduced muscle mass in T2DM.

METHODS

We conducted a cross-sectional study to investigate the association of serum UA with muscle mass in 401 subjects with T2DM (209 men and 192 postmenopausal women). The relative skeletal muscle mass index (RSMI) was evaluated using whole-body dual-energy x-ray absorptiometry.

RESULTS

Multiple regression analyses adjusted for body weight, age, serum creatinine, hemoglobin A1c (HbA1c), and duration of T2DM showed that serum UA was negatively associated with RSMI in all subjects and men with T2DM (β=-0.13, p=0.001 and β=-0.17, p=0.003, respectively). Moreover, logistic regression analyses adjusted for these confounding factors showed that a higher serum UA level was significantly associated with low RSMI in men with T2DM [odds ratio (OR)=1.94, 95% confidence interval (CI)=1.10-3.45 per SD increase, p=0.023]. In addition, higher serum UA levels were significantly associated with low RSMI after additional adjustment for age, duration of T2DM, HbA1c level, serum creatinine level, and sex in all subjects with T2DM [OR=1.80, 95% CI=1.20-2.72 per SD increase, p=0.005].

CONCLUSIONS

The present study showed for the first time that higher serum UA is an independent risk factor of reduced muscle mass in men with T2DM.

Association of hemoglobin concentration with handgrip strength in relation to hepatocyte growth factor levels among elderly Japanese men aged 60-69 years: a cross-sectional study

Background

Hemoglobin concentration reportedly is positively associated with muscle strength, for example, handgrip strength. However, hemoglobin cannot repair muscle directly, but is beneficial only in a supportive role. Since hepatocyte growth factor (HGF) regulates muscle satellite cell production and differentiation, which is stimulated by organ injury, the supportive effect of hemoglobin should thus be stronger for participants with high HGF than for those with low HGF. However, the association between hemoglobin concentration and handgrip strength in relation to HGF levels remains unknown.

Methods

We conducted a cross-sectional study of 255 Japanese elderly men aged 60–69 years who participated in annual health check-ups in 2014–2015. The study population was categorized on the basis of a median value of HGF of 300.6 pg/mL.

Results

Among present study population, 128 participants showed low HGF. For participants with low HGF, hemoglobin concentration showed no significant association with handgrip strength (standardized parameter estimate (β) = 0.03, p = 0.767), but for those with high HGF, hemoglobin concentration was significantly positively associated with handgrip strength (β = 0.23, p = 0.014).

Conclusions

A significant positive association between hemoglobin level and handgrip strength was established for elderly Japanese men aged 60–69 years with high HGF but not for participants with low HGF. Our finding indicates that HGF levels could determine the relationship of hemoglobin concentration with handgrip strength in elderly Japanese men aged 60–69 years. This result can be expected to serve as an effective tool for the clarification of the roles played by HGF and hemoglobin concentration in maintenance of muscle strength.

Angiogenesis: focusing on the effects of exercise in aging and cancer

[Purpose]

Although it is known that exercise induces angiogenesis, a clear mechanism has remained elusive due to various experimental limitations. This review presents the current status of angiogenesis-related experiments and future directions of experimentation in relation to exercise, aging, and cancer.

[Methods]

We conducted a PubMed search of the available literature to identify reported exercise related changes of angiogenic factors obtained in vitro using C2C12 cells and endothelial cells, and in vivo using animal experiments and in clinical studies.

[Results]

Exercise induced angiogenesis under normal conditions. Aging decreased angiogenic factors and increased during exercise. On the other hand, in cancer, the results indicate that angiogenic factors tend to increase in general, and that the effects of exercise need to be studied more. The exact mechanism remains unclear.

[Conclusion]

The effect of exercise on angiogenesis appears positive. Both resistance and aerobic exercise have positive effects, but many evidences suggest that the effects are more pronounced with aerobic exercise. Further research on the precise mechanism(s) is necessary. It is expected that these studies will include models of aging and cancer.

Coenzyme Q10 Prevents Senescence and Dysfunction Caused by Oxidative Stress in Vascular Endothelial Cells

Oxidative damage in endothelial cells is proposed to play an important role in endothelial dysfunction and atherogenesis. We previously reported that the reduced form of coenzyme Q10 (CoQ₁₀H₂) effectively inhibits oxidative stress and decelerates senescence in senescence-accelerated mice. Here, we treated human umbilical vein endothelial cells (HUVECs) with H₂O₂ and investigated the protective effect of CoQ₁₀H₂ against senescence, oxidative damage, and reduction in cellular functions. We found that CoQ₁₀H₂ markedly reduced the number of senescence-associated β-galactosidase-positive cells and suppressed the expression of senescence-associated secretory phenotype-associated genes in H₂O₂-treated HUVECs. Furthermore, CoQ₁₀H₂ suppressed the generation of intracellular reactive oxygen species (ROS) but promoted NO production that was accompanied by increased eNOS expression. CoQ₁₀H₂ prevented apoptosis and reductions in mitochondrial function and reduced migration and tube formation activity of H₂O₂-treated cells. The present study indicated that CoQ₁₀H₂ protects endothelial cells against senescence by promoting mitochondrial function and thus could delay vascular aging.

Relationship between oxidative stress and muscle mass loss in early postmenopause: an exploratory study

BACKGROUND

Endocrine changes due to menopause have been associated to oxidative stress and muscle mass loss. The study objective was to determine the relationship between both variables in early postmenopause.

MATERIAL AND METHODS

An exploratory, cross-sectional study was conducted in 107 pre- and postmenopausal women (aged 40-57 years). Levels of serum lipid peroxides and uric acid and enzymes superoxide dismutase and glutathione peroxidase, as well as total plasma antioxidant capacity were measured as oxidative stress markers. Muscle mass using bioelectrical impedance and muscle strength using dynamometry were also measured. Muscle mass, skeletal muscle index, fat-free mass, and body mass index were calculated.

RESULTS

More than 90% of participants were diagnosed with overweight or obesity. Postmenopausal women had lower values of muscle mass and strength markers, with a negative correlation between lipid peroxide level and skeletal muscle index (r= -0.326, p<.05), and a positive correlation between uric acid and skeletal muscle index (r=0.295, p<.05). A multivariate model including oxidative stress markers, age, and waist circumference showed lipid peroxide level to be the main contributor to explain the decrease in skeletal muscle mass in postmenopause, since for every 0.1μmol/l increase in lipid peroxide level, skeletal muscle index decreases by 3.03 units.

CONCLUSION

Our findings suggest an association between increased oxidative stress and muscle mass loss in early postmenopause.

Effects of Resistance Training on Matrix Metalloproteinase Activity in Skeletal Muscles and Blood Circulation During Aging

Aging is a complex, multifactorial process characterized by the accumulation of deleterious effects, including biochemical adaptations of the extracellular matrix (ECM). The purpose of this study was to investigate the effects of 12 weeks of resistance training (RT) on metalloproteinase 2 (MMP-2) activity in skeletal muscles and, MMP-2 and MMP-9 activity in the blood circulation of young and old rats. Twenty-eight Wistar rats were randomly divided into four groups (n = 7 per group): young sedentary (YS); young trained (YT), old sedentary (OS), and old trained (OT). The stair climbing RT consisted of one training session every 2 other day, with 8–12 dynamic movements per climb. The animals were euthanized 48 h after the end of the experimental period. MMP-2 and MMP-9 activity was measured by zymography. There was higher active MMP-2 activity in the lateral gastrocnemius and flexor digitorum profundus muscles in the OT group when compared to the OS, YS, and YT groups (p ≤ 0.001). Moreover, there was higher active MMP-2 activity in the medial gastrocnemius muscle in the OT group when compared to the YS and YT groups (p ≤ 0.001). The YS group presented lower active MMP-2 activity in the soleus muscle than the YT, OS, OT groups (p ≤ 0.001). With respect to active MMP-2/9 activity in the bloodstream, the OT group displayed significantly reduced activity (p ≤ 0.001) when compared to YS and YT groups. In conclusion, RT up-regulates MMP-2 activity in aging muscles, while down-regulating MMP-2 and MMP-9 in the blood circulation, suggesting that it may be a useful tool for the maintenance of ECM remodeling.

Role of Dietary Protein and Muscular Fitness on Longevity and Aging

Muscle atrophy is an unfortunate effect of aging and many diseases and can compromise physical function and impair vital metabolic processes. Low levels of muscular fitness together with insufficient dietary intake are major risk factors for illness and mortality from all causes. Ultimately, muscle wasting contributes significantly to weakness, disability, increased hospitalization, immobility, and loss of independence. However, the extent of muscle wasting differs greatly between individuals due to differences in the aging process per se as well as physical activity levels. Interventions for sarcopenia include exercise and nutrition because both have a positive impact on protein anabolism but also enhance other aspects that contribute to well-being in sarcopenic older adults, such as physical function, quality of life, and anti-inflammatory state. The process of aging is accompanied by chronic immune activation, and sarcopenia may represent a consequence of a counter-regulatory strategy of the immune system. Thereby, the kynurenine pathway is induced, and elevation in the ratio of kynurenine to tryptophan concentrations, which estimates the tryptophan breakdown rate, is often linked with inflammatory conditions and neuropsychiatric symptoms. A combined exercise program consisting of both resistance-type and endurance-type exercise may best help to ameliorate the loss of skeletal muscle mass and function, to prevent muscle aging comorbidities, and to improve physical performance and quality of life. In addition, the use of dietary protein supplementation can further augment protein anabolism but can also contribute to a more active lifestyle, thereby supporting well-being and active aging in the older population.

Sialic acid deficiency is associated with oxidative stress leading to muscle atrophy and weakness in GNE myopathy

Sialic acids are monosaccharides found in terminal sugar chains of cell surfaces and proteins; they have various biological functions and have been implicated in health and disease. Genetic defects of the GNE gene which encodes a critical bifunctional enzyme for sialic acid biosynthesis, lead to GNE myopathy, a disease manifesting with progressive muscle atrophy and weakness. The likely mechanism of disease is a lack of sialic acids. There remains, however, an unexplained link between hyposialylation and the muscle atrophy and weakness. In this study, we found that muscle proteins were highly modified by S-nitrosylation, and that oxidative stress-responsive genes were significantly upregulated, in hyposialylated muscles from human GNE myopathy patients and model mice. In both in vitro and in vivo models, the production of reactive oxygen species (ROS) was elevated with cellular hyposialylation, and increasing overall sialylation by extrinsic sialic acid intake reduced ROS and protein S-nitrosylation. More importantly, the antioxidant, oral N-acetylcysteine led to amelioration of the muscle atrophy and weakness in Gne mutant mice. Our data provide evidence of additional important function of sialic acids as a ROS scavenger in skeletal muscles, expanding our understanding on how sialic acid deficiency contributes to disease pathology, and identify oxidative stress as a therapeutic target in GNE myopathy.

Altered S-nitrosylation of p53 is responsible for impaired antioxidant response in skeletal muscle during aging

p53 transcriptional activity has been proposed to regulate both homeostasis and sarcopenia of skeletal muscle during aging. However, the exact molecular function of p53 remains to be clearly defined. We demonstrated a requirement of nuclear p53 S-nitrosylation in inducing a nitric oxide/PGC-1α-mediated antioxidant pathway in skeletal muscle. Importantly, mutant form of p53-DNA binding domain (C124S) did not undergo nuclear S-nitrosylation and failed in inducing the expression of antioxidant genes (i.e. SOD2 and GCLC). Moreover, we found that during aging the nuclear S-nitrosylation of p53 significantly declines in gastrocnemius/soleus leading to an impairment of redox homeostasis of skeletal muscle. We suggested that decreased level of nuclear neuronal nitric oxide synthase (nNOS)/Syntrophin complex, which we observed during aging, could be responsible for impaired nuclear S-nitrosylation. Taken together, our data indicate that altered S-nitrosylation of p53 during aging could be a contributing factor of sarcopenia condition and of other skeletal muscle pathologies associated with oxidative/nitrosative stress.

Associations of dietary patterns with bone mass, muscle strength and balance in a cohort of Australian middle-aged women

Influences of dietary patterns on musculoskeletal health are poorly understood in middle-aged women. This cross-sectional analysis from a cohort of 347 women (aged 36-57 years) aimed to examine associations between dietary patterns and musculoskeletal health outcomes in middle-aged women. Diet was measured by the Cancer Council of Victoria FFQ. Total body bone mineral content (TB BMC), femoral neck and lumbar spine bone density (dual-energy X-ray absorptiometry), lower limbs muscle strength (LMS) and balance tests (timed up and go test, step test, functional reach test (FRT) and lateral reach test) were also measured. Exploratory factor analysis was used to identify dietary patterns and scores for each pattern generated using factor loadings with absolute values ≥0·20. Associations between food pattern scores and musculoskeletal outcomes were assessed using multivariable linear regression. Three dietary patterns were identified: 'Healthy' (high consumption of a plant-based diet - vegetables, legumes, fruit, tomatoes, nuts, snacks, garlic, whole grains and low intake of high-fat dairy products), 'high protein, high fat' (red meats, poultry, processed meats, potatoes, cruciferous and dark-yellow vegetables, fish, chips, spirits and high-fat dairy products) and 'Processed foods' (high intakes of meat pies, hamburgers, beer, sweets, fruit juice, processed meats, snacks, spirits, pizza and low intake of cruciferous vegetables). After adjustment for confounders, Healthy pattern was positively associated with LMS, whereas Processed foods pattern was inversely associated with TB BMC and FRT. The associations were not significant after accounting for multiple comparisons. There were no associations with any other outcomes. These results suggest that maintaining a healthy diet could contribute to bone acquisition, muscle strength and balance in adult life. However, while they provide some support for further investigating dietary strategies for prevention of age-related loss of muscle and deterioration in balance, the exploratory nature of the analyses means that confirmation in longitudinal studies and/or trials with pre-specified hypotheses is needed.

Mitochondrial-Targeted Antioxidant Maintains Blood Flow, Mitochondrial Function, and Redox Balance in Old Mice Following Prolonged Limb Ischemia

Aging is a major factor in the decline of limb blood flow with ischemia. However, the underlying mechanism remains unclear. We investigated the role of mitochondrial reactive oxygen species (ROS) with regard to limb perfusion recovery in aging during ischemia. We performed femoral artery ligation in young and old mice with or without treatment with a scavenger of mitochondrial superoxide, MitoTEMPO (180 μg/kg/day, from pre-operative day 7 to post-operative day (POD) 21) infusion using an implanted mini-pump. The recoveries of cutaneous blood flow in the ischemic hind limb were lower in old mice than in young mice but were improved in MitoTEMPO-treated old mice. Mitochondrial DNA damage appeared in ischemic aged muscles but was eliminated by MitoTEMPO treatment. For POD 2, MitoTEMPO treatment suppressed the expression of p53 and the ratio of Bax/Bcl2 and upregulated the expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in ischemic aged skeletal muscles. For POD 21, MitoTEMPO treatment preserved the expression of PGC-1α in ischemic aged skeletal muscle. The ischemic soleus of old mice showed a lower mitochondrial respiratory control ratio in POD 21 compared to young mice, which was recovered in MitoTEMPO-treated old mice. Scavenging of mitochondrial superoxide attenuated mitochondrial DNA damage and preserved the mitochondrial respiration, in addition to suppression of the expression of p53 and preservation of the expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) in ischemic skeletal muscles with aging. Resolution of excessive mitochondrial superoxide could be an effective therapy to recover blood flow of skeletal muscle during ischemia in senescence.

The clinical characteristics of patients with mitochondrial tRNA Leu(UUR)m.3243A > G mutation: Compared with type 1 diabetes and early onset type 2 diabetes

OBJECTIVE

This study presents nine patients with mitochondrial tRNA Leu (UUR) m.3243A>G mutation and compares the clinical characteristics and diabetes complications with type 1 diabetes (T1DM) or early onset type 2 diabetes (T2DM).

METHODS

The study covers 9 patients with MIDD, 33 patients with T1DM and 86 patients (age of onset ≤35years) with early onset T2DM, matched for sex, age at onset of diabetes, duration of diabetes. All patients with MIDD were confirmed as carrying the m.3243A>G mitochondrial DNA mutation. Serum HbA1c, beta-cell function, retinal and renal complications of diabetes, bone metabolic markers, lumbar spine and femoral neck BMD bone mineral density were compared to characterize the clinical features of all patients.

RESULTS

Nine patients were from five unrelated families, and the mean (SD) onset age of those patients was 31.2±7.2year. Two patients required insulin at presentation, and six patients progressed to insulin requirement after a mean of 7.2years. β-Cell function in the MIDD group was intermediate between T1DM and early-onset T2DM. In MIDD, four patients were diagnosed as diabetic retinopathy (4/9) and five patients (5/9) had macroalbuminuria. The number of patients with diabetic retinopathy and macroalbuminuria in the MIDD group was comparable to T1DM or early-onset T2DM. The rate of osteoporosis (BMD T-score<-2.5 SD) in the patient with MIDD was higher than the T1DM or early-onset T2DM group.

CONCLUSION

Our study indicates that of the nine subjects with MIDD, three patients (1-II-1, 1-II-3, 1-II-4) who came from the same family had a history of acute pancreatitis. Compared with T1DM or early-onset T2DM matched for sex, age, duration of diabetes, MIDD patients had the highest rate of osteoporosis.

Relationships among Disability, Quality of Life, and Physical Fitness in Lumbar Spinal Stenosis: An Investigation of Elderly Korean Women

STUDY DESIGN

A cross-sectional, case-control study.

PURPOSE

To investigate associations between physical fitness measures and disabilities related to back pain and quality of life (QOL) by the presence of symptomatic lumbar spinal stenosis (LSS) in elderly Korean women.

OVERVIEW OF LITERATURE

LSS leads to decreased functioning and reduced QOL. However, correlations among physical fitness, disability, and QOL have not been investigated in elderly women with LSS.

METHODS

Participants included women aged 65 years and older (n=192), divided into a study group (n=38) and a control group (n=154) based on the presence/absence of LSS. All participants underwent physical function and fitness tests. Oswestry disability index (ODI) scores and EuroQol five-dimensional questionnaire (EQ-5D-5L) scores were used to assess disability and health-related QOL.

RESULTS

The results for the handgrip strength, sit-and-reach, functional reach, and timed up and go (TUG) tests were significantly higher in the control group than the LSS group. ODI scores were significantly higher and EQ-5D-5L scores significantly lower in the LSS group. TUG and functional reach test scores were significantly correlated with ODI scores, and handgrip strength was strongly interrelated with ODI and EQ-5D-5L scores in the LSS group. No other physical fitness measures showed statistically significant relationships with ODI or EQ-5D-5L scores.

CONCLUSIONS

In elderly Korean women with LSS, back pain-related disability and QOL are significantly associated with some physical fitness parameters such as handgrip strength. Handgrip strength reflects general muscle strength, which is significantly interrelated with the level of disability and QOL. Our results suggest that enhancing generalized muscle strength helps to reduce disability due to back pain and improve QOL in patients with LSS.

Tocotrienol-Rich Fraction Ameliorates Antioxidant Defense Mechanisms and Improves Replicative Senescence-Associated Oxidative Stress in Human Myoblasts

During aging, oxidative stress affects the normal function of satellite cells, with consequent regeneration defects that lead to sarcopenia. This study aimed to evaluate tocotrienol-rich fraction (TRF) modulation in reestablishing the oxidative status of myoblasts during replicative senescence and to compare the effects of TRF with other antioxidants (α-tocopherol (ATF) and N-acetyl-cysteine (NAC)). Primary human myoblasts were cultured to young, presenescent, and senescent phases. The cells were treated with antioxidants for 24 h, followed by the assessment of free radical generation, lipid peroxidation, antioxidant enzyme mRNA expression and activities, and the ratio of reduced to oxidized glutathione. Our data showed that replicative senescence increased reactive oxygen species (ROS) generation and lipid peroxidation in myoblasts. Treatment with TRF significantly diminished ROS production and decreased lipid peroxidation in senescent myoblasts. Moreover, the gene expression of superoxide dismutase (SOD2), catalase (CAT), and glutathione peroxidase (GPX1) was modulated by TRF treatment, with increased activity of superoxide dismutase and catalase and reduced glutathione peroxidase in senescent myoblasts. In comparison to ATF and NAC, TRF was more efficient in heightening the antioxidant capacity and reducing free radical insults. These results suggested that TRF is able to ameliorate antioxidant defense mechanisms and improves replicative senescence-associated oxidative stress in myoblasts.

Association between serum uric acid concentrations and grip strength: Is there effect modification by age?

BACKGROUND

Given that some of the deleterious effects of uric acid (UA) on health are greater in younger than in older subjects, and that age is strongly associated with skeletal muscle composition and function, this study tested the hypothesis that the association between UA and muscle strength differs by age.

METHODS

Cross-sectional analysis with 3595 individuals who participated in NHANES 2011-2012. Serum uric acid was determined by the uricase-peroxidase technique. Grip strength was calculated as the average of the best measure obtained in each hand with a Takei digital grip strength dynamometer. Linear regression models were adjusted for the main confounders.

RESULTS

In individuals aged 20-40 years, the beta coefficients (95% CI) of muscle strength as dependent variable and UA as independent variable comparing the second and third to the lowest tertile of UA were -0.45 kg (-1.46; 0.57) and -2.36 kg (-3.27; -1.44), respectively, p-linear trend ≤0.01. By contrast, in subjects aged 40-60 years the corresponding beta coefficients were 0.21 kg (-1.00; 1.42) and -0.45 kg (-2.10; 1.20), p-linear trend: 0.60; and for subjects ≥60 years they were 0.58 kg (-3.27; 1.65) and 1.57 kg (0.63; 2.50), p-linear trend <0.01. These results held after numerous sensitivity analyses.

CONCLUSION

The association between UA and muscle strength differed depending on age: while a negative link was observed in adults aged 20-40 years, this relationship disappeared later in life, and was reversed after the age of 60. Future research should evaluate if uric acid targets for individuals with hyperuricemia should consider patients age and muscle strength.

Mitochondrial reactive oxygen species: Do they extend or shorten animal lifespan?

Testing the predictions of the Mitochondrial Free Radical Theory of Ageing (MFRTA) has provided a deep understanding of the role of reactive oxygen species (ROS) and mitochondria in the aging process. However those data, which support MFRTA are in the majority correlative (e.g. increasing oxidative damage with age). In contrast the majority of direct experimental data contradict MFRTA (e.g. changes in ROS levels do not alter longevity as expected). Unfortunately, in the past, ROS measurements have mainly been performed using isolated mitochondria, a method which is prone to experimental artifacts and does not reflect the complexity of the in vivo process. New technology to study different ROS (e.g. superoxide or hydrogen peroxide) in vivo is now available; these new methods combined with state-of-the-art genetic engineering technology will allow a deeper interrogation of, where, when and how free radicals affect aging and pathological processes. In fact data that combine these new approaches, indicate that boosting mitochondrial ROS in lower animals is a way to extend both healthy and maximum lifespan. In this review, I discuss the latest literature focused on the role of mitochondrial ROS in aging, and how these new discoveries are helping to better understand the role of mitochondria in health and disease. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.

Oxidative stress response and Nrf2 signaling in aging

Increasing oxidative stress, a major characteristic of aging, has been implicated in a variety of age-related pathologies. In aging, oxidant production from several sources is increased, whereas antioxidant enzymes, the primary lines of defense, are decreased. Repair systems, including the proteasomal degradation of damaged proteins, also decline. Importantly, the adaptive response to oxidative stress declines with aging. Nrf2/EpRE signaling regulates the basal and inducible expression of many antioxidant enzymes and the proteasome. Nrf2/EpRE activity is regulated at several levels, including transcription, posttranslation, and interactions with other proteins. This review summarizes current studies on age-related impairment of Nrf2/EpRE function and discusses the changes in Nrf2 regulatory mechanisms with aging.