Biomarkers in sarcopenia: A multifactorial approach

A Randomized-Controlled Trial Pilot Study Examining the Effect of Pelvic Floor Muscle Training on the Irisin Concentration in Overweight or Obese Elderly Women with Stress Urinary Incontinence

Objective

This study aimed to examine the effect of pelvic floor muscle training on the irisin (Ir) concentration in overweight or obese elderly women with stress urinary incontinence.

Methods

The number of participants included in analysis was 49: 28 women in the experimental group and 21 women in the control group. The experimental group (EG) underwent pelvic floor muscle training, whereas no therapeutic intervention was applied to the control group (CG). Irisin concentration, severity of urinary incontinence (RUIS), and body mass index (BMI) were measured in all women at the initial and final assessments.

Results

By comparing the initial and final assessment results we have been able to demonstrate statistically significant differences in the measured variables in the experimental group. No statistically significant differences in the measured variables were reported for the control group at the initial and final assessments. Moderate negative correlation was observed between the BMI results with the irisin concentration results in the EG at the initial assessment and no correlation at the final assessment. Weak positive correlation was observed between the BMI results with the irisin concentration in the CG at the initial and final assessment.

Conclusion

Further studies are necessary to observe the regulation of irisin concentration and explain mechanisms underlying these effects.

POSSIBLE ROLE OF NUTRITION IN PREVENTION OF SARCOPENIA AND FALLS

Objective: In this review, we analyze the foundation of sarcopenia as a potentially modifiable risk factor for falls, and we try to formulate practical strategies for nutritional interventions aimed at reducing the risk for sarcopenia and falls in our elderly patients. Methods: An extensive literature search was performed using the PubMed and the Google Scholar databases. Results: Falls are a common and costly source of injury and death in elderly adults. A large proportion of injurious falls are due to a trip or slip, suggesting that muscular factors are major determinants of both fall risk and the risk for fall-related injury. Conclusion: An increasing body of evidence links sarcopenia, the loss of muscle strength and mass that occurs with advancing age, with an increased risk for falls. Nutritional factors, as well as exercise, can help with both prevention and treatment of sarcopenia and may reduce the risk of falls in the elderly. Abbreviations: 25-OHD = 25-hydroxyvitamin D; EAA = essential amino acid; IGF-1 = insulin-like growth factor 1; IU = international units; MPS = muscle protein synthesis; PUFA = polyunsaturated fatty acid.

The metabolomics side of frailty: Toward personalized medicine for the aged

Frailty encompasses several domains (i.e., metabolic, physical, cognitive). The multisystem derangements underlying frailty pathophysiology, its phenotypic heterogeneity, and the fluctuations of individuals across severity states have hampered a comprehensive appraisal of the condition. Circulating biomarkers emerged as an alleged tool for capturing this complexity and, as proxies for organismal metabolic changes, may hold the advantages of: 1) supporting diagnosis, 2) tracking the progression, 3) assisting healthcare professionals in clinical and therapeutic decision-making, and 4) verifying the efficacy of an intervention before measurable clinical manifestations occur. Among available analytical tools, metabolomics are able to identify and quantify the (ideally) whole repertoire of small molecules in biological matrices (i.e., cells, tissues, and biological fluids). Results of metabolomics analysis may define the final output of genome-environment interactions at the individual level. This entire collection of metabolites is called "metabolome" and is highly dynamic. Here, we discuss how monitoring the dynamics of metabolic profiles may provide a read-out of the environmental and clinical disturbances affecting cell homeostasis in frailty-associated conditions.

The Biological Foundations of Sarcopenia: Established and Promising Markers

Sarcopenia, the progressive loss of muscle mass and strength, is one of the major health issues in older adults, given its high prevalence accompanied by huge clinical and socioeconomic implications. Age-related changes in skeletal muscle can be attributed to mechanisms both directly and indirectly related to muscle homeostasis. Indeed, a wide spectrum of age-related modifications in the organism was shown to play a key role in the pathogenesis of sarcopenia. Not surprisingly, sarcopenia has sometimes been indicated as a syndrome stemming from the aging process, and not as univocal standalone disease. Due to the multidimensionality of sarcopenia, a single biomarker approach is not enough to explain the biology of this condition. The aim of this review is to suggest innovative and promising sarcopenia markers investigating the link between skeletal muscle and brain. Indeed, as a neurological origin of sarcopenia has been hypothesized, a new perspective on sarcopenia biomarkers may focus on the dysfunction of the neuromuscular junctions (NMJs). The core SNARE synaptosomal-associated protein of 25 kDa (SNAP25) accumulates in the plasma membrane of nerve terminals at NMJs and regulates exocytosis at peripheral and central synapses. Interestingly, mice studies have shown that SNAP25 affects the neuromuscular function. SNARE complex and, in particular, SNAP25 may represent a promising pathway to explore the molecular and cellular mechanisms regulating muscular homeostasis and concur at profiling the sarcopenia biological background.

Age-Related DNA Methylation Changes: Potential Impact on Skeletal Muscle Aging in Humans

Human aging is accompanied by a decline in muscle mass and muscle function, which is commonly referred to as sarcopenia. Sarcopenia is associated with detrimental clinical outcomes, such as a reduced quality of life, frailty, an increased risk of falls, fractures, hospitalization, and mortality. The exact underlying mechanisms of sarcopenia are poorly delineated and the molecular mechanisms driving the development and progression of this disorder remain to be uncovered. Previous studies have described age-related differences in gene expression, with one study identifying an age-specific expression signature of sarcopenia, but little is known about the influence of epigenetics, and specially of DNA methylation, in its pathogenesis. In this review, we will focus on the available knowledge in literature on the characterization of DNA methylation profiles during skeletal muscle aging and the possible impact of physical activity and nutrition. We will consider the possible use of the recently developed DNA methylation-based biomarkers of aging called epigenetic clocks in the assessment of physical performance in older individuals. Finally, we will discuss limitations and future directions of this field.

Improvements in Phase Angle Are Related With Muscle Quality Index After Resistance Training in Older Women

The aim of this study was to analyze the association between muscle quality index (MQI) and phase angle (PhA) after a program of progressive resistance training (RT) in older women. Sixty-six older women with previous RT experience (68.8 ± 4.6 years, 156.6 ± 5.3 cm, 66.0 ± 13.0 kg, and 26.7 ± 4.6 kg/m2) underwent 12 weeks of RT (3 ×/week, eight exercises, and 10-15 repetition maximum). Anthropometry, muscular strength (one-repetition maximum tests), and body composition (dual-energy X-ray absorptiometry and spectral bioimpedance) were measured pre- and posttraining. There were observed significant increases for PhA, MQI, muscular strength, muscle mass, and reactance, whereas no significant changes in body fat and resistance were found. A significant correlation was observed between the RT-induced relative changes in PhA and MQI (r = .620). We conclude that improvements in MQI induced by RT are associated with increases in PhA. Therefore, PhA may be a valid tool to track changes in MQI after 12 weeks of RT in older women.

Nutritional status and body fat mass: Determinants of sarcopenia in community-dwelling older adults

BACKGROUND

Sarcopenia is defined as the old age syndrome characterized by profound decline in muscle mass and function. This study aimed to investigate the prevalence of sarcopenia and its risk factors in older adults.

METHODS

Totally, 501 older people aged 65 years and older were recruited. Sarcopenia was defined according to the criteria of the Asian Working Group for Sarcopenia (AWGS). For obtaining Skeletal Muscle mass Index (SMI), body composition was evaluated using Bioelectrical Impedance Analysis (BIA). Muscle strength and physical performance were measured by Handgrip Strength (HGS) and Gait Speed (GS), respectively. Nutritional status, physical activity level, and biochemical indicators were assessed, as well.

RESULTS

The prevalence of sarcopenia was 20.8%. Multiple logistic regression models of the predictors of decline in the components of sarcopenia showed that older age, low Body Mass Index (BMI), and serum albumin level were associated with a higher risk of low SMI. Low serum albumin level and older age were also predictive of low HGS. Besides, old age, high body fat mass, and low BMI were the risk factors of low GS. Conversely, increased Calf Circumference (CC) was protective against low SMI and GS. Finally, older age, male gender, low BMI, decreased mini-nutritional assessment score, low serum albumin level, and high body fat were associated with a higher risk of sarcopenia, whereas higher CC reduced its risk.

CONCLUSION

The prevalence of sarcopenia is high among elderly individuals. This study underlined that sarcopenia might develop in older adults with impaired nutritional status and high body fat mass. Further studies could evaluate the effects of appropriate nutritional interventions on sarcopenia management and prevention.

Effects of linear versus nonperiodized resistance training on isometric force and skeletal muscle mass adaptations in sarcopenic older adults

The aim of this study was to compare the effects of linear periodization (LP) versus nonperiodized (NP) resistance training on upper-body isometric force and skeletal muscle mass (SMM) in sarcopenic older adults. Twenty sarcopenic older adults were randomly assigned into the LP and NP groups and performed 16 weeks of resistance training. The SMM was measured by octopolar bioelectrical impedance. The isometric force for handgrip and trunk were assessed by dynamometer. Evaluations were performed at baseline, after 4, 8, 12, and 16 weeks of resistance training. For total weight lifted, there was a main effect for time (F=126.986, P<0.001), statistically significant difference between condition (F=13.867, P=0.001) and interaction (F=8.778, P<0.001), whereby total weight lifted was greater for NP after 4 months of training. Isometric force for handgrip and trunk increased across time (P<0.001) but no significant differences between groups or interaction were observed (P>0.05). The SMM increased across time (P<0.05), however no significant difference between groups or interaction were observed (P>0.05). There were strong and significant correlations between handgrip maximum force and SMM (LP: rho=0.79, P=0.004 vs. NP: rho=−0.43, P=0.244) and handgrip mean force and SMM (LP: rho=0.68, P=0.021 vs. NP: rho=−0.37, P=0.332) only for the LP group. In conclusion, LP and NP resistance training induced similar benefits on upper-body isometric force and SMM in sarcopenic older adults. However, LP presented lower total weight lifted, suggesting that it is possible to obtain similar gains in isometric force and SMM with less total work.

Sarcopenia: revised European consensus on definition and diagnosis

Background

in 2010, the European Working Group on Sarcopenia in Older People (EWGSOP) published a sarcopenia definition that aimed to foster advances in identifying and caring for people with sarcopenia. In early 2018, the Working Group met again (EWGSOP2) to update the original definition in order to reflect scientific and clinical evidence that has built over the last decade. This paper presents our updated findings.

Objectives

to increase consistency of research design, clinical diagnoses and ultimately, care for people with sarcopenia.

Recommendations

sarcopenia is a muscle disease (muscle failure) rooted in adverse muscle changes that accrue across a lifetime; sarcopenia is common among adults of older age but can also occur earlier in life. In this updated consensus paper on sarcopenia, EWGSOP2: (1) focuses on low muscle strength as a key characteristic of sarcopenia, uses detection of low muscle quantity and quality to confirm the sarcopenia diagnosis, and identifies poor physical performance as indicative of severe sarcopenia; (2) updates the clinical algorithm that can be used for sarcopenia case-finding, diagnosis and confirmation, and severity determination and (3) provides clear cut-off points for measurements of variables that identify and characterise sarcopenia.

Conclusions

EWGSOP2's updated recommendations aim to increase awareness of sarcopenia and its risk. With these new recommendations, EWGSOP2 calls for healthcare professionals who treat patients at risk for sarcopenia to take actions that will promote early detection and treatment. We also encourage more research in the field of sarcopenia in order to prevent or delay adverse health outcomes that incur a heavy burden for patients and healthcare systems.

Tracking disease progression non-invasively in Duchenne and Becker muscular dystrophies

BACKGROUND

Analysis of muscle biopsies allowed to characterize the pathophysiological changes of Duchenne and Becker muscular dystrophies (D/BMD) leading to the clinical phenotype. Muscle tissue is often investigated during interventional dose finding studies to show in situ proof of concept and pharmacodynamics effect of the tested drug. Less invasive readouts are needed to objectively monitor patients' health status, muscle quality, and response to treatment. The identification of serum biomarkers correlating with clinical function and able to anticipate functional scales is particularly needed for personalized patient management and to support drug development programs.

METHODS

A large-scale proteomic approach was used to identify serum biomarkers describing pathophysiological changes (e.g. loss of muscle mass), association with clinical function, prediction of disease milestones, association with in vivo ³¹ P magnetic resonance spectroscopy data and dystrophin levels in muscles. Cross-sectional comparisons were performed to compare DMD patients, BMD patients, and healthy controls. A group of DMD patients was followed up for a median of 4.4 years to allow monitoring of individual disease trajectories based on yearly visits.

RESULTS

Cross-sectional comparison enabled to identify 10 proteins discriminating between healthy controls, DMD and BMD patients. Several proteins (285) were able to separate DMD from healthy, while 121 proteins differentiated between BMD and DMD; only 13 proteins separated BMD and healthy individuals. The concentration of specific proteins in serum was significantly associated with patients' performance (e.g. BMP6 serum levels and elbow flexion) or dystrophin levels (e.g. TIMP2) in BMD patients. Analysis of longitudinal trajectories allowed to identify 427 proteins affected over time indicating loss of muscle mass, replacement of muscle by adipose tissue, and cardiac involvement. Over-representation analysis of longitudinal data allowed to highlight proteins that could be used as pharmacodynamic biomarkers for drugs currently in clinical development.

CONCLUSIONS

Serum proteomic analysis allowed to not only discriminate among DMD, BMD, and healthy subjects, but it enabled to detect significant associations with clinical function, dystrophin levels, and disease progression.

Improving the comprehension of sarcopenic state determinants: An multivariate approach involving hormonal, nutritional, lifestyle and genetic variables

It is known that sarcopenia is a multifaceted phenomenon, which involves genetic, nutritional, hormonal and living habits aspects. Then, an integrated analysis, as a multivariate approach, could improve the comprehension about the determinants of sarcopenic state in old adults. The present study aimed to investigate the interaction among serum vitamin D, daily caloric and protein intake, lifestyle habits, ACE I/D gene polymorphism and sarcopenic state in community-dwelling old adults. One hundred one community-dwelling old adults were clinically stratified as sarcopenic or non-sarcopenic. Serum vitamin D, daily caloric and protein intake, lifestyle habits (smoking, physical activity level and sedentary behavior) and ACE I/D gene polymorphism were recorded. A multivariate logistic regression technique was applied to investigate the interaction among the selected independent variables and the sarcopenic state. The independent variables age, smoking, serum Vitamin D and ACE I/D polymorphism achieved the statistical criteria to be inserted in the multivariate analysis. After a stepwise procedure from the multivariate logistic regression, the variables age, serum Vitamin D and ACE I/D polymorphism remained, together, in the final model. Sarcopenic state was significantly associated to older age, II-genotype and low serum Vitamin D in old adults from 60 years old.

Sarcopenia: assessment of disease burden and strategies to improve outcomes

Life expectancy is increasing worldwide, with a resultant increase in the elderly population. Aging is characterized by the progressive loss of skeletal muscle mass and strength - a phenomenon called sarcopenia. Sarcopenia has a complex multifactorial pathogenesis, which involves not only age-related changes in neuromuscular function, muscle protein turnover, and hormone levels and sensitivity, but also a chronic pro-inflammatory state, oxidative stress, and behavioral factors - in particular, nutritional status and degree of physical activity. According to the operational definition by the European Working Group on Sarcopenia in Older People (EWGSOP), the diagnosis of sarcopenia requires the presence of both low muscle mass and low muscle function, which can be defined by low muscle strength or low physical performance. Moreover, biomarkers of sarcopenia have been identified for its early detection and for a detailed identification of the main pathophysiological mechanisms involved in its development. Because sarcopenia is associated with important adverse health outcomes, such as frailty, hospitalization, and mortality, several therapeutic strategies have been identified that involve exercise training, nutritional supplementation, hormonal therapies, and novel strategies and are still under investigation. At the present time, only physical exercise has showed a positive effect in managing and preventing sarcopenia and its adverse health outcomes. Thus, further well-designed and well-conducted studies on sarcopenia are needed.

Identifying Frail-Related Biomarkers among Community-Dwelling Older Adults in Japan: A Research Example from the Japanese Gerontological Evaluation Study

We examined correlating clinical biomarkers for the physical aspect of frailty among community-dwelling older adults in Japan, using Japanese Gerontological Evaluation Study (JAGES). We used information from the JAGES participants (N = 3,128) who also participated in the community health screening in 2010. We grouped participants' response to the Study of Osteoporotic Fracture (SOF) Frailty Index into robust (=0), intermediate frail (=1), and frail (=2+) ones to indicate physical aspect of frailty. Independent of sex and age, results from multinomial logistic regression showed above normal albumin and below normal HDL and haemoglobin levels were positively associated with intermediate frail (RRR = 1.99, 95% CI = 1.22–3.23; RRR = 1.36, 95% CI = 1.33–1.39; RRR = 1.36, 95% CI = 1.23–1.51, resp.) and frail cases (RRR = 2.27, 95% CI = 1.91–2.70; RRR = 1.59, 95% CI = 1.51–1.68; RRR = 1.40, 95% CI = 1.28–1.52, resp.). Limited to women, above normal Hb1Ac level was similarly associated with intermediate frail and frail cases (RRR = 1.18, 95% CI = 1.02, 1.38; RRR = 2.56, 95% CI = 2.23–2.95, resp.). Use of relevant clinical biomarkers can help in assessment of older adults' physical aspect of frailty.

Role of Inactivity in Chronic Diseases: Evolutionary Insight and Pathophysiological Mechanisms

This review proposes that physical inactivity could be considered a behavior selected by evolution for resting, and also selected to be reinforcing in life-threatening situations in which exercise would be dangerous. Underlying the notion are human twin studies and animal selective breeding studies, both of which provide indirect evidence for the existence of genes for physical inactivity. Approximately 86% of the 325 million in the United States (U.S.) population achieve less than the U.S. Government and World Health Organization guidelines for daily physical activity for health. Although underappreciated, physical inactivity is an actual contributing cause to at least 35 unhealthy conditions, including the majority of the 10 leading causes of death in the U.S. First, we introduce nine physical inactivity-related themes. Next, characteristics and models of physical inactivity are presented. Following next are individual examples of phenotypes, organ systems, and diseases that are impacted by physical inactivity, including behavior, central nervous system, cardiorespiratory fitness, metabolism, adipose tissue, skeletal muscle, bone, immunity, digestion, and cancer. Importantly, physical inactivity, itself, often plays an independent role as a direct cause of speeding the losses of cardiovascular and strength fitness, shortening of healthspan, and lowering of the age for the onset of the first chronic disease, which in turn decreases quality of life, increases health care costs, and accelerates mortality risk.

The impact of nutrition on quality of life of patients with hepatitis C

PURPOSE OF REVIEW

The aim of this study was to review the most recent aspects of nutrition and its impact on health-related quality of life (HRQOL) in patients with chronic hepatitis C (CHC).

RECENT FINDINGS

Low HRQOL scores have been found in all stages of hepatitis C virus (HCV) infection. Of the factors linked to HRQOL, three aspects should be emphasized, nutritional status, physical activity and mental health status. Regarding the nutrition and metabolic conditions, a broad spectrum of nutritional disorders may impact on HRQOL of patients with CHC.

SUMMARY

Malnutrition, which is a significant comorbidity in end-stage of all chronic liver diseases, has been recognized as a significant factor related to poor HRQOL. Of note, in individuals chronically infected with HCV, low muscle skeletal mass, an early indicator of undernourishment, precedes the development of cirrhosis. Because of the strict linkage between HRQOL, nutrition and physical activity, the assessment of the musculoskeletal system abnormalities in every patient with CHC, independently of the stage of the liver disease, is of utmost relevance. Maintenance of healthy skeletal muscle is essential to reduce the negative effects of sarcopenia on HRQOL. Otherwise, overweight/obesity and chronic HCV infection can cause insulin resistance, which has been associated with HRQOL impairment.

The increased risk of sarcopenia in patients with cardiovascular risk factors in Suburb-Dwelling older Chinese using the AWGS definition

The aim of the present study is to investigate the relationship between sarcopenia and cardiovascular risk factors (CVRF) in the Chinese elderly. A total of 1611 elderly individuals aged ≥60 years were enrolled in this study. The well-established CVRF of diabetes, hypertensions, and dyslipidemia were assessed. Sarcopenia was defined according to the recommended algorithm of the Asian Working Group for Sarcopenia (AWGS). Multiple logistic regression analyses and the linear regressions were used to evaluate the components of CVRF and the number of CVRF of elderly patients with sarcopenia. After adjusting for potential confounders, CVRF was associated with a high prevalence of sarcopenia in elderly Chinese populations. Furthermore, diabetes and hypertension, but not dyslipidemia, were found to be significantly associated with sarcopenia. The OR and 95% CI for sarcopenia of the participants with 1, 2, and 3 features of CVRF were 2.27(1.14-4.48), 4.13(1.80-9.46), and 4.90(1.01-23.81), respectively. A linear increase in the prevalence of sarcopenia was found to be associated with the number of CVRF components in the elderly population (P values for the trends < 0.001). Knowledge of known CVRF, particularly diabetes and hypertension, may help predict the risk for sarcopenia in the elderly.

Targeted quantification of lipid mediators in skeletal muscles using restricted access media-based trap-and-elute liquid chromatography-mass spectrometry

Lipid mediators (LMs) are a class of bioactive metabolites of the essential polyunsaturated fatty acids (PUFA), which are involved in many physiological processes. Their quantification in biological samples is critical for understanding their functions in lifestyle and chronic diseases, such as diabetes, as well allergies, cancers, and in aging processes. We developed a rapid, and sensitive LC-MS/MS method to quantify the concentrations of 14 lipid mediators of interest in mouse skeletal muscle tissue without time-consuming liquid-liquid or solid-phase extractions. A restricted-access media (RAM) based trap was used prior to LC-MS as cleanup process to prevent the analytical column from clogging and deterioration. The system enabled automatic removal of residual proteins and other biological interferences presented in the tissue extracts; the target analytes were retained in the trap and then eluted to an analytical column for separation. Matrix evaluation tests demonstrated that the use of the combined RAM trap and chromatographic separation efficiently eliminated the biological or chemical matrix interferences typically encountered in bioanalytical analysis. Using 14 LM standards and 12 corresponding deuterated compounds as internal standards, the five-point calibration curves, established over the concentration range of 0.031-320 ng mL^-1, demonstrated good linearity of r² > 0.9903 (0.9903-0.9983). The lower detection limits obtained were 0.016, 0.031, 0.062, and 0.31 ng mL^-1 (0.5, 1, 2, and 10 pg on column), respectively, depending on the specific compounds. Good accuracy (87.1-114.5%) and precision (<13.4%) of the method were observed for low, medium, and high concentration quality control samples. The method was applied to measure the amount of 14 target LMs in mouse skeletal muscle tissues. All 14 analytes in this study were successfully detected and quantified in the gastrocnemius muscle samples, which provided crucial information for both age and gender-related aspects of LMs signaling in skeletal muscles previously unknown. This method could be applied to advance the understanding of skeletal muscle pathophysiology to study the role of LMs in health and disease. Furthermore, we will expand the application of this methodology to humans and other tissues/matrices in the near future.

Low serum concentrations of Irisin are associated with increased risk of hip fracture in Chinese older women

OBJECTIVE

Irisin derived from muscle in response to exercise may be the molecular entity responsible for muscle wasting-osteoporosis connectivity in the elderly. The objective of the study was to determine whether serum Irisin (sIrisin) provides information on hip fracture prediction which were independent of bone mineral density (BMD) and the fracture risk assessment tool (FRAX) algorithm.

METHODS

This study enrolled 160 older women (ages, 70-90y) with minimal trauma hip fractures (MTHFs) and 160 age-matched women without fracture serving as controls. Clinical features, BMD and bone turnover markers including sIrisin levels were measured after fracture within 2 days as baseline.

RESULTS

sIrisin levels were significantly lower (361.5±140.0ng/mL vs 478.5±159.6ng/mL, P<0.001) in cases than controls. After multivariate analysis, sIrisin remained as an independent variable of BMD, which explained 17.8% of femoral neck BMD and 22.5% of lumbar spine BMD, respectively. The odds ratio (OR) of MTHFs comparing the lowest (<320.1ng/mL) to highest (>524.5ng/mL) quartiles was 1.95 (95% CI 1.23-3.79, P<0.05) for sIrisin. Adjustment for age, body mass index, time since menopause and exercise ≥30min/day yielded similar results, and BMD of femoral neck also did not change these associations. Taking FRAX score into account attenuated the association somewhat: OR of hip fracture was 1.81 (95% CI 1.26-3.49, P<0.05) in first versus fourth quartile of sIrisin. There was a negative gradient of risk by decreasing quartile in sIrisin.

CONCLUSIONS

Low concentrations of sIrisin in older women were independently associated with increased risk of hip fractures when adjusted for BMD or FRAX score.

Changes in pro-inflammatory markers and leucine concentrations in response to Nordic Walking training combined with vitamin D supplementation in elderly women

Mechanisms underpinning age-related decreases in muscle strength and muscle mass relate to chronic inflammation. Physical activity induces an anti-inflammatory effect, but it is modulated by additional factors. We hypothesized that vitamin D, which has also anti-inflammatory activity will modify adaptation to exercise and reduce inflammation in elderly women. Twenty-seven women aged 67 ± 8 years were included and divided into groups with baseline vitamin D concentration more than 20 ng mL⁻¹ (MVD) and less than 20 ng mL⁻¹ (LVD). Both groups performed 1 h Nordic Walking (NW) training combined with vitamin D supplementation for 12 weeks. Serum concentrations of inflammation markers, branched amino acids, vitamin D, muscle strength and balance were assessed at the baseline and three days after intervention. The training caused the significant decrease in concentration of pro-inflammatory proteins HMGB1 (30 ± 156%; 90% CI) and IL-6 (−10 ± 66%; 90% CI) in MVD group. This effects in group MVD were moderate, indicating vitamin D as one of the modifiers of these exercise-induced changes. Rise of myokine irisin induced by exercise correlated inversely with HMGB1 and the correlation was more pronounced at the baseline as well as after training among MVD participants. Although the intervention caused the leucine level to rise, a comparison of the recorded response between groups and the adjusted effect indicated that the effect was 20% lower in the LVD group. Overall the applied training program was effective in reducing HMGB1 concentration. This drop was accompanied by the rise of myokine irisin and better uptake of leucine among women with higher baseline vitamin D.