Decline In Skeletal Muscle Mass Research Articles

Receptor-Mediated Muscle Homeostasis as a Target for Sarcopenia Therapeutics.

Sarcopenia is a disease characterized by age-related decline of skeletal muscle mass and function. The molecular mechanisms of the pathophysiology of sarcopenia form a complex network due to the involvement of multiple interconnected signaling pathways. Therefore, signaling receptors are major targets in pharmacological strategies in general. To provide a rationale for pharmacological interventions for sarcopenia, we herein describe several druggable signaling receptors based on their role in skeletal muscle homeostasis and changes in their activity with aging. A brief overview is presented of the efficacy of corresponding drug candidates under clinical trials. Strategies targeting the androgen receptor, vitamin D receptor, Insulin-like growth factor-1 receptor, and ghrelin receptor primarily focus on promoting anabolic action using natural ligands or mimetics. Strategies involving activin receptors and angiotensin receptors focus on inhibiting catabolic action. This review may help to select specific targets or combinations of targets in the future.

Longitudinal Changes in Body Composition Following Hematopoietic Cell Transplantation

Sarcopenia, the loss of skeletal muscle tissue, has been identified as a potential risk factor for adverse outcomes in hematopoietic cell transplantation (HCT) recipients. However, much remains unknown about longitudinal changes in body composition following HCT. We retrospectively evaluated computed tomography (CT) imaging from 315 lymphoma patients undergoing HCT at our institution between 2000 and 2014. Two HCT cohorts were established: auto-HCT (did not receive allo-HCT, n=218) and allo-HCT (may have received previous auto-HCT, n=97). Cross-sectional area of lean muscle, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) were measured at the level of the third lumbar vertebral body (L3) on an axial CT image prior to HCT, 1 year post-HCT, and 2.5 years post-HCT. Lean muscle was normalized for height and reported as L3 skeletal muscle index (L3SMI). Sarcopenia was defined as L3SMI ≤39 cm2/m2 for women and ≤55 cm2/m2for men.Sarcopenia prior to HCT was observed in 50% of HCT recipients, 47% in the auto-HCT cohort and 57% in the allo-HCT cohort. The number of lines of therapy prior to HCT was predictive of sarcopenia prior to HCT (OR=1.29, p=.01). There was a significant decline in skeletal muscle mass over time for patients in the allo-HCT cohort when compared to the trend in the auto-HCT cohort (-6.52 cm2/imaging interval, p=<0.01) (Figure 1). In the allo-HCT cohort, the association between the change in muscle mass (per cm2) from prior to HCT to 2.5 years post-HCT and moderate-severe chronic GVHD did meet statistical significance (OR 1.04, p=0.03). The incidence of sarcopenia increased over time in all patients receiving HCT (OR=1.55; p=0.02), particularly driven by patients undergoing allo-HCT who experienced an increased rate of sarcopenia over time compared to auto-HCT (OR=1.66, p=0.02). The incidence of sarcopenia reached 66% at 2.5 years post-HCT in the allo-HCT cohort (Figure 2). In the allo-HCT cohort, the association between sarcopenia at 2.5 years post-HCT and moderate-severe chronic GVHD did not meet statistical significance (OR 3.32, p=0.07). Adipose tissue analysis showed allo-HCT recipients had lower measurements of SAT at all time point when compared to patients in the auto-HCT cohort. There was a significant increase in both VAT and SAT experienced by recipients of auto-HCT and allo-HCT when comparing CT images from 1 year post-HCT and 2.5 years post-HCT (p<0.05). However, there was no significant difference in change in SAT or VAT over time when comparing auto-HCT and allo-HCT cohorts.In conclusion, retrospective analysis of CT imaging revealed significant loss of muscle mass and an increased incidence of sarcopenia following HCT, especially in patients undergoing allo-HCT. Future studies are needed to further characterize changes in body composition in HCT recipients and investigate its impact on HCT outcomes. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Sarcopenic Characteristics of Active Older Adults: a Cross-Sectional Exploration

BackgroundAgeing is associated with a decline in skeletal muscle mass and function (strength and power), known as sarcopenia. Inadequate dietary protein and inactivity have been shown to accelerate sarcopenia outcomes, occurring at different rates in males and females. Regardless, active older adults who often exceed the exercise guidelines still show signs of sarcopenia. This study aimed to explore the link between age, physical activity, protein intake, and biological sex with skeletal muscle mass, strength, power, and physical capacity/performance in active older adults. Fifty-four active older adults were recruited from this trial and grouped according to age (middle aged: 50–59 years, and older age: ≥ 60 years), exercise volume (low: ≥ 90–149 min/week, moderate: ≥ 150–299 min/week, and high: ≥ 300 min/week), protein intake (low: < 0.8 g/kg body mass (BM), moderate: ≥ 0.8–1.19g /kg BM, and high: ≥ 1.2 g/kg BM), and biological sex (males and females). Skeletal muscle and fat mass (dual X-ray absorptiometry), strength (1-repetition maximum using leg press, chest press, lateral pull down, and hand grip), power (counter movement jump), and general fitness (cardiorespiratory capacity and gait speed) were assessed. Data were grouped based on variables, and a general linear model (ANCOVA) or an independent t test was used to determine between group differences.ResultsFifty three of the total participants’ data were analysed. The middle-aged group had 18%, 11%, and 10% higher leg press, chest press, and lateral pull down, respectively, compared to the older-aged group (p < .05). There were no significant differences between different levels of training volume and any of the outcomes. Higher protein intakes were associated with significantly less body fat mass (p = .005) and a trend towards a higher leg press (p = .053) and higher relative power (W/kg) (p = .056) compared with the moderate and low protein intake groups. Significant differences based on biological sex were observed for all outcomes except for gait speed (p = .611) and cardiorespiratory fitness (p = .147).ConclusionsContributions of age, physical activity, daily protein intake, and biological sex can explain the individual variation in outcomes related to changes in body composition, strength, power, and/or cardiorespiratory fitness in a cohort of active older adults.The preprint version of this work is available on Research Square: https://www.researchsquare.com/article/rs-51873/v1.Trial RegistrationThis trial is registered in the ANZCTR.org.au, no. ACTRN12618001088235 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375286).

Evaluation of sarcopenia in long-lived elderly patients: comparison between the Muscle Mass Index and the Calf Circumference

The increase in life expectancy, observed in several countries, including Brazil, is due to improvements in living and health conditions and the epidemiological transition from the causes of morbidity and mortality, from infectious and parasitic diseases to chronic diseases. Furthermore, an increase in longevity, in addition to advances in science, with the improvement of diagnoses and the search for new treatments contributed to the increase in years lived1,2.&#x0D; However, the aging process is associated with a decrease in organic functions over the years. Sarcopenia is considered a complex geriatric syndrome and is defined as an age-related decline in skeletal muscle mass and function2. It is a major public health concern because it can result in functional decline, disability, falls, increased hospitalization costs, poor quality of life, and even deaths3. Although Dual-energy X-ray Absorptiometry (DXA) is the most used method to estimate the loss of muscle mass4 the high cost and low viability hinder its use in Primary Health Care (PHC). Methods such as Muscle Mass Index (MMI) and Calf Circumference (CC) can be used replacing DXA due to ease of access and application as well as low cost5.&#x0D; The Academic League of Geriatrics and Gerontology, Três Lagoas Campus, Federal Univeristy of Mato Grosso do Sul designed and executed a research intending to evaluate several aspects in elderly people with extreme longevity. One of the variables analyzed was sarcopenia, which was evaluated and compared using MMI and CC. For this purpose, a cross-sectional and quantitative study was performed in 2019/2020, with n = 69 individuals aged ≥ 90 years, of both genders, users of the Unified Health System in the town of Três Lagoas – MS. A sociodemographic questionnaire containing gender, age, and years of schooling was applied. Anthropometric data (CC and MMI) were collected in triplicate. The skeletal muscle mass was determined using the formula of Lee and collaborators which considers age, body mass, gender, ethnicity and height5. The values of MMI ​​of Janssen and collaborators were used as a reference to classify whether the nonagenarian or centenarians were sarcopenic or not6. For CC, a cutoff score ≤ 31 centimeters was adopted as a sign of sarcopenia7.&#x0D; The interviewed elderly had an average age of 93.5 years old, 1.3 years of schooling and 52.2% of the participants were women. The average CC was 31.2 centimeters, with 46.1% being considered sarcopenic patients according to this parameter. The average MMI was 5.1 kg/m2, with 100% of the elderly patients being considered sarcopenic through this method. There was no relationship between CC and MMI (p = 0.213).&#x0D; The high rates of sarcopenia found, especially using MMI and the absence of a relationship between the CC and MMI highlights the need to use more reliable methods to evaluate sarcopenia in long-lived elderly people, since the identification from CC, despite being easy and fast, may not be sensitive in this age group. These findings also lead to considering the use of more specific methods or those associated with other variables, such as Timed up and Go (TUG), for the evaluation of sarcopenia in the elderly aged 90 years or over.&#x0D; Future investigations should consider the importance of validating specific instruments for elderly people in extreme longevity, as they constitute a group that has unique characteristics. The screening, monitoring, and health promotion carried out by PHC teams can promote the improvement in the quality of life of elderly people in extreme longevity.

The ketogenic diet preserves skeletal muscle with aging in mice.

The causes of the decline in skeletal muscle mass and function with age, known as sarcopenia, are poorly understood. Nutrition (calorie restriction) interventions impact many cellular processes and increase lifespan and preserve muscle mass and function with age. As we previously observed an increase in life span and muscle function in aging mice on a ketogenic diet (KD), we aimed to investigate the effect of a KD on the maintenance of skeletal muscle mass with age and the potential molecular mechanisms of this action. Twelve‐month‐old mice were assigned to an isocaloric control or KD until 16 or 26 months of age, at which time skeletal muscle was collected for evaluating mass, morphology, and biochemical properties. Skeletal muscle mass was significantly greater at 26 months in the gastrocnemius of mice on the KD. This result in KD mice was associated with a shift in fiber type from type IIb to IIa fibers and a range of molecular parameters including increased markers of NMJ remodeling, mitochondrial biogenesis, oxidative metabolism, and antioxidant capacity, while decreasing endoplasmic reticulum (ER) stress, protein synthesis, and proteasome activity. Overall, this study shows the effectiveness of a long‐term KD in mitigating sarcopenia. The diet preferentially preserved oxidative muscle fibers and improved mitochondrial and antioxidant capacity. These adaptations may result in a healthier cellular environment, decreasing oxidative and ER stress resulting in less protein turnover. These shifts allow mice to better maintain muscle mass and function with age.

Practical applications of whey protein in supporting skeletal muscle maintenance, recovery, and reconditioning.

Like humans, many companion animals experience a gradual decline in skeletal muscle mass and function during later years of life. This process, analogous to sarcopenia in humans, increases risk for morbidity and mortality. Periods of reduced activity due to injury or illness, followed by an incomplete recovery, can accelerate the loss of muscle mass and function. Emerging research from human studies suggests that moderate amounts of high-quality protein may attenuate the loss of muscle, while preventing accumulation of fat during periods of disuse. Whey protein is a consumer-friendly and readily available source of high-quality protein. It supports skeletal muscle maintenance during normal aging and may also provide anabolic support during periods of illness, injury, and recovery. Ongoing research efforts continue to refine our understanding of how protein quality, quantity, and meal timing can be optimized to support retention of muscle mass and function during aging. Priority research areas include supplementation with high-quality protein during illness/injury to stimulate anabolism by targeting molecular mechanisms that regulate skeletal muscle metabolism.

Relationship Between Bioelectrical Impedance Parameters and Appendicular Muscle Functional Quality in Older Adults from South-Western Poland.

PurposeThe aim of this research was to assess the correlations between the impedance components and the appendicular skeletal muscle strength and functional quality indices in older adults. The use of the impedance parameters as potential identifiers characterizing the functional state of muscles could improve methods of monitoring “healthy ageing”.Patients and MethodsA total of 346 subjectively healthy adults aged 50–83 years were subjected to tests. Body mass and height, hand grip strength and knee extensor strength were measured. Resistance, reactance and phase angle were measured using the bioelectrical impedance method. The relationship between the impedance parameters and the appendicular skeletal muscle strength and quality indices was evaluated using stepwise multiple regression.ResultsParticipants aged ≥65 years were found to be characterized by lower values of the impedance parameters and the appendicular skeletal muscle strength and functional quality indices than participants 10 years younger. In both groups of sexes, the relative percentage differences in limb strength between the age groups were 3–6 times greater than the differences in appendicular skeletal muscle mass. Significant regression models for muscle strength and quality, with strong age, sex and reactance prediction and a weaker phase angle effect, were obtained.ConclusionThe impedance components explain the part of changes in muscle strength which is independent of the decline in skeletal muscle mass. Phase angle and reactance can be suitable for diagnosing and preventing dangers connected with the decline in muscle quality, but it is necessary to establish their normalized reference values for older adults.

Recent advances and future avenues in understanding the role of adipose tissue cross talk in mediating skeletal muscle mass and function with ageing

Sarcopenia, broadly defined as the age-related decline in skeletal muscle mass, quality, and function, is associated with chronic low-grade inflammation and an increased likelihood of adverse health outcomes. The regulation of skeletal muscle mass with ageing is complex and necessitates a delicate balance between muscle protein synthesis and degradation. The secretion and transfer of cytokines, long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), both discretely and within extracellular vesicles, have emerged as important communication channels between tissues. Some of these factors have been implicated in regulating skeletal muscle mass, function, and pathologies and may be perturbed by excessive adiposity. Indeed, adipose tissue participates in a broad spectrum of inter-organ communication and obesity promotes the accumulation of macrophages, cellular senescence, and the production and secretion of pro-inflammatory factors. Pertinently, age-related sarcopenia has been reported to be more prevalent in obesity; however, such effects are confounded by comorbidities and physical activity level. In this review, we provide evidence that adiposity may exacerbate age-related sarcopenia and outline some emerging concepts of adipose-skeletal muscle communication including the secretion and processing of novel myokines and adipokines and the role of extracellular vesicles in mediating inter-tissue cross talk via lncRNAs and miRNAs in the context of sarcopenia, ageing, and obesity. Further research using advances in proteomics, transcriptomics, and techniques to investigate extracellular vesicles, with an emphasis on translational, longitudinal human studies, is required to better understand the physiological significance of these factors, the impact of obesity upon them, and their potential as therapeutic targets in combating muscle wasting.

Beneficial Effects of a Mixture of Algae and Extra Virgin Olive Oils on the Age-Induced Alterations of Rodent Skeletal Muscle: Role of HDAC-4.

Aging is associated with a progressive decline in skeletal muscle mass, strength and function (sarcopenia). We have investigated whether a mixture of algae oil (25%) and extra virgin olive oil (75%) could exert beneficial effects on sarcopenia. Young (3 months) and old (24 months) male Wistar rats were treated with vehicle or with the oil mixture (OM) (2.5 mL/kg) for 21 days. Aging decreased gastrocnemius weight, total protein, and myosin heavy chain mRNA. Treatment with the OM prevented these effects. Concomitantly, OM administration decreased the inflammatory state in muscle; it prevented the increase of pro-inflammatory interleukin-6 (IL-6) and the decrease in anti-inflammatory interleukin-10 (IL-10) in aged rats. The OM was not able to prevent aging-induced alterations in either the insulin-like growth factor I/protein kinase B (IGF-I/Akt) pathway or in the increased expression of atrogenes in the gastrocnemius. However, the OM prevented decreased autophagy activity (ratio protein 1A/1B-light chain 3 (LC3b) II/I) induced by aging and increased expression of factors related with muscle senescence such as histone deacetylase 4 (HDAC-4), myogenin, and IGF-I binding protein 5 (IGFBP-5). These data suggest that the beneficial effects of the OM on muscle can be secondary to its anti-inflammatory effect and to the normalization of HDAC-4 and myogenin levels, making this treatment an alternative therapeutic tool for sarcopenia.

Dietary protein interventions to improve nutritional status in end-stage renal disease patients undergoing hemodialysis.

Poor nutritional status is prevalent among end-stage renal disease patients undergoing hemodialysis. Chronic hemodialysis patients show an accelerated decline in skeletal muscle mass and strength, which is associated with higher mortality rates and a reduced quality of life. The current review aims to summarize recent advances regarding underlying causes of muscle loss and interventions that support muscle mass maintenance in patients with chronic hemodialysis. Muscle maintenance in chronic hemodialysis patients is compromised by low dietary protein intake levels, anabolic resistance of skeletal muscle tissue, sedentary behavior, and amino acid removal during hemodialysis. Studies assessing the effect of increased protein intake on nutritional status generally show beneficial results, especially in hypoalbuminemic chronic hemodialysis patients. The muscle protein synthetic response following protein ingestion in chronic hemodialysis patients may be enhanced through incorporation of structured physical activity and/or concurrent ketoacid ingestion. A coordinated program that combines nutritional and physical activity interventions is likely required to attenuate the decline in muscle mass and strength of chronic hemodialysis patients. Nephrologists, dieticians, and exercise specialists should collaborate closely to establish guidelines regarding the appropriate quantity and timing of protein ingestion. In addition, they should provide tailored nutritional and physical activity interventions for chronic hemodialysis patients (see video, Supplemental Digital Content 1, Video abstract, http://links.lww.com/COCN/A14).

Vitamin D and Sarcopenia: Potential of Vitamin D Supplementation in Sarcopenia Prevention and Treatment.

Skeletal muscle, the largest organ in the human body, accounting for approximately 40% of body weight, plays important roles in exercise and energy expenditure. In the elderly, there is often a progressive decline in skeletal muscle mass and function, a condition known as sarcopenia, which can lead to bedridden conditions, wheelchair confinement as well as reducing the quality of life (QOL). In developed countries with aging populations, the prevention and management of sarcopenia are important for the improvement of health and life expectancy in these populations. Recently, vitamin D, a fat-soluble vitamin, has been attracting attention due to its importance in sarcopenia. This review will focus on the effects of vitamin D deficiency and supplementation on sarcopenia.

Molecular mechanisms of cancer cachexia‑induced muscle atrophy (Review).

Muscle atrophy is a severe clinical problem involving the loss of muscle mass and strength that frequently accompanies the development of numerous types of cancer, including pancreatic, lung and gastric cancers. Cancer cachexia is a multifactorial syndrome characterized by a continuous decline in skeletal muscle mass that cannot be reversed by conventional nutritional therapy. The pathophysiological characteristic of cancer cachexia is a negative protein and energy balance caused by a combination of factors, including reduced food intake and metabolic abnormalities. Numerous necessary cellular processes are disrupted by the presence of abnormal metabolites, which mediate several intracellular signaling pathways and result in the net loss of cytoplasm and organelles in atrophic skeletal muscle during various states of cancer cachexia. Currently, the clinical morbidity and mortality rates of patients with cancer cachexia are high. Once a patient enters the cachexia phase, the consequences are difficult to reverse and the treatment methods for cancer cachexia are very limited. The present review aimed to summarize the recent discoveries regarding the pathogenesis of cancer cachexia-induced muscle atrophy and provided novel ideas for the comprehensive treatment to improve the prognosis of affected patients.

Daily Oral Administration of Protease-Treated Royal Jelly Protects Against Denervation-Induced Skeletal Muscle Atrophy.

Honeybees produce royal jelly (RJ) from their cephalic glands. Royal jelly is a source of nutrition for the queen honey bee throughout its lifespan and is also involved in fertility and longevity. Royal jelly has long been considered beneficial to human health. We recently observed that RJ delayed impairment of motor function during aging, affecting muscle fiber size. However, how RJ affects skeletal muscle metabolism and the functional component of RJ is as of yet unidentified. We demonstrate that feeding mice with RJ daily prevents a decrease in myofiber size following denervation without affecting total muscle weight. RJ did not affect atrophy-related genes but stimulated the expression of myogenesis-related genes, including IGF-1 and IGF receptor. Trans-10-hydroxy-2-decenoic acid (10H2DA) and 10-hydroxydecanoic acid (10HDAA), two major fatty acids contained in RJ. After ingestion, 10H2DA and 10HDAA are metabolized into 2-decenedioic acid (2DA) and sebacic acid (SA) respectively. We found that 10H2DA, 10HDAA, 2DA, and SA all regulated myogenesis of C2C12 cells, murine myoblast cells. These novel findings may be useful for potential preventative and therapeutic applications for muscle atrophy disease included in Sarcopenia, an age-related decline in skeletal muscle mass and strength.

Antioxidants in Sport Sarcopenia.

The decline of skeletal muscle mass and strength that leads to sarcopenia is a pathology that might represent an emergency healthcare issue in future years. Decreased muscle mass is also a condition that mainly affects master athletes involved in endurance physical activities. Skeletal muscles respond to exercise by reshaping the biochemical, morphological, and physiological state of myofibrils. Adaptive responses involve the activation of intracellular signaling pathways and genetic reprogramming, causing alterations in contractile properties, metabolic status, and muscle mass. One of the mechanisms leading to sarcopenia is an increase in reactive oxygen and nitrogen species levels and a reduction in enzymatic antioxidant protection. The present review shows the recent experimental models of sarcopenia that explore molecular mechanisms. Furthermore, the clinical aspect of sport sarcopenia will be highlighted, and new strategies based on nutritional supplements, which may contribute to reducing indices of oxidative stress by reinforcing natural endogenous protection, will be suggested.

Dietary acid-base load and its association with risk of osteoporotic fractures and low estimated skeletal muscle mass.

Age-related decline in skeletal muscle mass and strength, loss of bone density, and increased risk of osteoporotic fractures are important public health issues. Systemic acid-base balance is affected by dietary intake and may be relevant to these conditions. We therefore investigated associations of dietary acid-base load with skeletal muscle mass, bone density status, and fracture risk. We analysed the European Prospective Investigation into Cancer and Nutrition-Norfolk cohort of >25,000 individuals, 39-79 years at baseline. Potential renal acid load (PRAL) was calculated from 7-day food diary data. As a proxy for skeletal muscle mass, we estimated fat-free mass from bioelectrical impedance analysis and scaled this for BMI (FFMBMI). Bone density status was assessed by heel-bone broadband ultrasound attenuation (BUA), and fracture rates were obtained from health-care records. Multivariable regression was used to test musculoskeletal outcomes across sex-specific quintiles of PRAL. PRAL in quintiles was negatively associated with FFMBMI in men (n = 6350, p < 0.001) and women (n = 7989, p < 0.001), with quintile 5 vs 1 differences of -1.5% and -3.2% (both p < 0.001). PRAL was also negatively associated with BUA in women (n = 8312, p = 0.016; quintile 5 vs 1 difference -1.5%, p = 0.024). The combined hazard of hip, wrist and spine fractures (mean ± SD follow-up 17.9 ± 4.9 years) was higher with increasing quintiles of PRAL in men (610 fractures; n = 11,511; p = 0.013) and women (1583 fractures; n = 13,927; p = 0.009), with quintile 5 vs 1 hazard ratios of 1.33 (95% CI: 1.03-1.72, p = 0.029) and 1.21 (95% CI: 1.03-1.42, p = 0.022), but associations were not consistent for all fractures sites and age groups tested. This study provides strong evidence, albeit observational, for a negative association between PRAL and musculoskeletal health in middle to older age men and women, and thus supports the rationale for a less acidic dietary load.

Sarcopenia in women with hip fracture: A comparison of hormonal biomarkers and their relationship to skeletal muscle mass and function

ObjectivesSarcopenia is a decline in skeletal muscle mass and function. It is associated with adverse outcomes and increased mortality. Sarcopenia is also reported to be prevalent in the hip fracture population. Our aims in this study are to compare the hormonal profile in women with hip fracture to controls, and to assess the relationship between hormonal biomarkers to skeletal muscle mass and function in these women. MethodsA cross sectional study was performed enrolling women above age 60 years old with hip fracture as a study group. For comparison healthy women from the community were recruited. Peripheral blood samples were obtained for analysis of hormonal profiles. Measures of skeletal muscle mass and function by muscle area on computed tomography, dual energy X-ray absorptiometry, bioelectrical impedance analysis, and grip strength was performed. ResultsA high proportion of sarcopenic individuals were detected in the hip fracture group (60%). Women with hip fracture compared to controls were older (P = 0.073), had lower serum albumin levels (P < 0.001), serum insulin-like growth factor-1 (IGF-1) (P < 0.001), insulin-like growth factor binding protein −3 (IGFBP-3) (P < 0.001), free testosterone levels (P = 0.001), and impaired beta cell function by homeostasis model assessment (HOMA beta) (P = 0.038). ConclusionsThere is a high proportion of sarcopenic individuals in the hip fracture group. Lowered serum levels of IGF-1 and IGFBP-3, HOMA beta cell function, and free testosterone levels were detected in this group and may serve as potential biomarkers of sarcopenia.

Assessment of muscle mass in critically ill patients: role of the sarcopenia index and images studies.

Sarcopenia is a progressive generalized decline in skeletal muscle mass, strength, and function. This condition is highly prevalent in critically ill patients and is associated with poor outcomes in the ICU. In this review, we describe the use, evidence, and limitations of the most common validated imaging studies used to assess muscle mass in ICU, and we provide an overview of the benefits of using the sarcopenia index [(serum creatinine/serum cystatin C) × 100]) in the ICU. Currently, the determination of muscle mass using anthropometric measurements and serum biomarkers is unreliable. Several new techniques, including a dual-energy X-ray absorptiometry, computed tomography scan, ultrasonography, and bioimpedance analysis, have been studied and validated for the diagnosis and prognosis of sarcopenia in the ICU. However, these techniques are often not accessible for the majority of critically ill patients. The sarcopenia index constitutes an accurate method to diagnose sarcopenia, predict ICU outcomes, and nutritional status in critically ill patients. Diagnosis of sarcopenia has substantial implications in ICU patients. Choosing the correct test to identify patients who may need preventive or therapeutic support for this condition will favorably impact ICU outcomes.

The Impact of Antidiabetic Agents on Sarcopenia in Type 2 Diabetes: A Literature Review.

Sarcopenia is a geriatric syndrome characterized by decline of skeletal muscle mass and function. Contributing factors include nutritional, genetic, inflammatory, and endocrinal factors. The reported prevalence of sarcopenia in type 2 diabetes mellitus is high, especially in patients with poor glycemic control. Additionally, antidiabetic agents may alter the balance between protein synthesis and degradation through various mechanisms of skeletal muscle mass regulation. This study reviewed the literature on the pathogenesis of sarcopenia in diabetes mellitus and the current understanding of whether antidiabetic agents contribute positively or negatively to sarcopenia and muscle wasting.

Serum sestrins: potential predictive molecule in human sarcopenia.

The aging trajectory from a state of robustness and good health proceeds from sarcopenia to frailty followed by disability and death due to decline in skeletal muscle mass and function. Sarcopenia is now formally recognized as a muscle disease with an ICD-10-MC diagnosis code. The autophagic response seems to be affected in the skeletal muscle during aging contributing to sarcopenia. Sestrins (Sesns) proteins play a critical role in autophagy induction under cellular stress conditions. The study aims to identify sarcopenia in older adults using Asian Working group guidelines (AWGS) to determine clinically relevant cut-off levels for diagnosis and their association with antioxidant protein Sesns. The study recruited 102 older adults attending Geriatric medicine OPD AIIMS, New Delhi, India. The level of serum Sesns were evaluated by Surface Plasmon Resonance (SPR) and validated by immunoblotting. Fifty older adults were diagnosed as sarcopenics according to AWGS. Sesn 1 (p = 0.0448) and Sesn 2 (p < 0.0001) levels were significantly reduced in sarcopenic compared to non-sarcopenic. ROC analysis showed a better cut-off of Sesn 2; 10.104ng/µL with 92% sensitivity and 84% specificity. Even after adjusting the values with respect to confounding factors, Sesn levels remained significantly reduced in sarcopenics (p < 0.030). The level of Sesn 2 showed positive co-relation with the characteristics of sarcopenia. This study first time reported the concentration of serum sestrin in sarcopenic older adults. It can be concluded that sarcopenia can be diagnosed at the early stage by using the serum sestrin scale as one of the potential biomarker.

Experimental Models of Sarcopenia: Bridging Molecular Mechanism and Therapeutic Strategy.

Sarcopenia has been defined as a progressive decline of skeletal muscle mass, strength, and functions in elderly people. It is accompanied by physical frailty, functional disability, falls, hospitalization, and mortality, and is becoming a major geriatric disorder owing to the increasing life expectancy and growing older population worldwide. Experimental models are critical to understand the pathophysiology of sarcopenia and develop therapeutic strategies. Although its etiologies remain to be further elucidated, several mechanisms of sarcopenia have been identified, including cellular senescence, proteostasis imbalance, oxidative stress, and “inflammaging.” In this article, we address three main aspects. First, we describe the fundamental aging mechanisms. Next, we discuss both in vitro and in vivo experimental models based on molecular mechanisms that have the potential to elucidate the biochemical processes integral to sarcopenia. The use of appropriate models to reflect sarcopenia and/or its underlying pathways will enable researchers to understand sarcopenia and develop novel therapeutic strategies for sarcopenia. Lastly, we discuss the possible molecular targets and the current status of drug candidates for sarcopenia treatment. In conclusion, the development of experimental models for sarcopenia is essential to discover molecular targets that are valuable as biochemical biomarkers and/or therapeutic targets for sarcopenia.