Cellular and molecular mechanisms underlying age-related skeletal muscle wasting and weakness

Effects of soy protein-rich meals on muscle health of older adults in long-term care: A randomized clinical trial

OBJECTIVE

This study investigated the effects of a soy protein-rich meal intervention on the muscle health of older adults in long-term care facilities.

METHODS

A 12-week single-center randomized controlled trial with a control-group and open-label design was conducted. Eighty-four older adults from a long-term care facility participated in the study. The chefs at the facility cooked three meals using soy protein-rich recipes designed by dieticians. For 12 weeks, the intervention group participants consumed three meals with 30 g of soy protein (10 g/meal) per day, and the control group participants maintained their habitual diets.

RESULTS

The 84 participants (mean age, 84.9 ± 7.0 years; 61.9% female) were randomly assigned to an intervention group (43 participants) and a control group (41 participants). The intervention group exhibited significant increases in several lean mass indicators, namely soft lean mass (mean, 1.43 kg; 95% confidence interval [CI]: 0.20-1.65 kg), skeletal muscle mass (mean, 1.20 kg; 95% CI: 0.43-1.96 kg), appendicular skeletal muscle mass (mean, 0.79 kg; 95% CI: 0.07-1.52 kg), and skeletal muscle index (mean, 0.37 kg/m2; 95% CI: 0.05-0.68 kg/m2) (all P < 0.05). These changes were not observed in the control group (all P > 0.05). Notably, calf circumference decreased significantly in the control group (mean, -0.98 cm; 95% CI: -1.61 to -0.36 cm) but was maintained in the intervention group. The differences in the calf circumference and 6-m walk performance of the two groups were significant (P < 0.05).

CONCLUSIONS

The 12-week soy protein-rich meal intervention improved the muscle mass and 6-m walk performance of older adults in a long-term care facility.

Mass Spectrometry-Based Multiomics Identifies Metabolic Signatures of Sarcopenia in Rhesus Monkey Skeletal Muscle

Sarcopenia is a progressive disorder characterized by age-related loss of skeletal muscle mass and function. Although significant progress has been made over the years to identify the molecular determinants of sarcopenia, the precise mechanisms underlying the age-related loss of contractile function remains unclear. Advances in "omics" technologies, including mass spectrometry-based proteomic and metabolomic analyses, offer great opportunities to better understand sarcopenia. Herein, we performed mass spectrometry-based analyses of the vastus lateralis from young, middle-aged, and older rhesus monkeys to identify molecular signatures of sarcopenia. In our proteomic analysis, we identified proteins that change with age, including those involved in adenosine triphosphate and adenosine monophosphate metabolism as well as fatty acid beta oxidation. In our untargeted metabolomic analysis, we identified metabolites that changed with age largely related to energy metabolism including fatty acid beta oxidation. Pathway analysis of age-responsive proteins and metabolites revealed changes in muscle structure and contraction as well as lipid, carbohydrate, and purine metabolism. Together, this study discovers new metabolic signatures and offers new insights into the molecular mechanisms underlying sarcopenia for the evaluation and monitoring of a therapeutic treatment of sarcopenia.

Association of phase angle with sarcopenia in patients undergoing maintenance hemodialysis: A case-control study

Background

Sarcopenia, characterized by reduced muscle strength and mass, is commonly observed in patients with kidney disease. This study aimed to investigate the factors that influence sarcopenia in patients undergoing maintenance hemodialysis (HD patients).

Materials and Methods

A case-control study was conducted from 2022 to 2023, involving a total of 137 HD patients receiving regular dialysis. Relevant data were collected, and based on diagnostic criteria, patients were classified into sarcopenia and nonsarcopenia groups. All patients received polysulfone membrane HD at a flow rate of 500 mL/min. Bioelectrical impedance analysis was used to evaluate phase angle (PhA), muscle volume, and body composition.

Results

The prevalence of sarcopenia among maintenance HD patients was found to be 40.14%. There was a higher proportion of women (76.36%) with sarcopenia compared to men (P < 0.001). Furthermore, a significant difference was observed in PhA (P < 0.006) between patients undergoing maintenance HD with and without sarcopenia. PhA was positively associated with body mass index, body cell mass, basal metabolic rate, fat-free mass, soft lean mass, and minerals, whereas age and skeletal muscle index showed an inverse significant correlation.

Conclusion

Sarcopenia, a condition associated with increased mortality risk, affects a considerable proportion of dialysis patients. It is imperative to urgently identify and develop preventive and therapeutic strategies to counteract the detrimental effects of sarcopenia on the health outcomes of kidney patients.

Biological basis and treatment of frailty and sarcopenia

In an ageing society, the importance of maintaining healthy life expectancy has been emphasized. As a result of age-related decline in functional reserve, frailty is a state of increased vulnerability and susceptibility to adverse health outcomes with a serious impact on healthy life expectancy. The decline in skeletal muscle mass and function, also known as sarcopenia, is key in the development of physical frailty. Both frailty and sarcopenia are highly prevalent in patients not only with advanced age but also in patients with illnesses that exacerbate their progression like heart failure (HF), cancer, or dementia, with the prevalence of frailty and sarcopenia in HF patients reaching up to 50-75% and 19.5-47.3%, respectively, resulting in 1.5-3 times higher 1-year mortality. The biological mechanisms of frailty and sarcopenia are multifactorial, complex, and not yet fully elucidated, ranging from DNA damage, proteostasis impairment, and epigenetic changes to mitochondrial dysfunction, cellular senescence, and environmental factors, many of which are further linked to cardiac disease. Currently, there is no gold standard for the treatment of frailty and sarcopenia, however, growing evidence supports that a combination of exercise training and nutritional supplement improves skeletal muscle function and frailty, with a variety of other therapies being devised based on the underlying pathophysiology. In this review, we address the involvement of frailty and sarcopenia in cardiac disease and describe the latest insights into their biological mechanisms as well as the potential for intervention through exercise, diet, and specific therapies.

In the land of not-unhappiness: On the state-of-the-art of targeting aging and age-related diseases by biomedical research

The concept of the Land of Not-Unhappiness refers to the potential achievement of eliminating the pathologies of the aging process. To inform of how close we are to settling in the land, we summarize and review the achievements of research on anti-aging interventions over the last hundred years with a specific focus on strategies that slow down metabolism, compensate for aging-related losses, and target a broad range of age-related diseases. We critically evaluate the existing interventions labeled as "anti-aging," such as calorie restriction, exercise, stem cell administration, and senolytics, to provide a down-to-earth evaluation of their current applicability in counteracting aging. Throughout the text, we have maintained a light tone to make it accessible to non-experts in biogerontology, and provide a broad overview for those considering conducting studies, research, or seeking to understand the scientific basis of anti-aging medicine.

The SGLT2 inhibitor empagliflozin inhibits skeletal muscle fibrosis in naturally aging male mice through the AMPKα/MMP9/TGF-β1/Smad pathway

ABSTACT

With advancing age, the incidence of sarcopenia increases, eventually leading to a cascade of adverse events. However, there is currently a lack of effective pharmacological treatment for sarcopenia. Sodium-glucose co-transporter 2 inhibitor (SGLT2i) empagliflozin demonstrates anti-fibrotic capabilities in various organs. This study aims to determine whether empagliflozin can improve skeletal muscle fibrosis induced by sarcopenia in naturally aging mice. A natural aging model was established by feeding male mice from 13 months of age to 19 months of age. A fibrosis model was created by stimulating skeletal muscle fibroblasts with TGF-β1. The Forelimb grip strength test assessed skeletal muscle function, and expression levels of COL1A1, COL3A1, and α-SMA were analyzed by western blot, qPCR, and immunohistochemistry. Additionally, levels of AMPKα/MMP9/TGFβ1/Smad signaling pathways were examined. In naturally aging mice, skeletal muscle function declines, expression of muscle fibrosis markers increases, AMPKα expression is downregulated, and MMP9/TGFβ1/Smad signaling pathways are upregulated. However, treatment with empagliflozin reverses this phenomenon. At the cellular level, empagliflozin exhibits similar anti-fibrotic effects, and these effects are attenuated by Compound C and siAMPKα. Empagliflozin exhibits anti-fibrotic effects, possibly associated with the AMPK/MMP9/TGFβ1/Smad signaling pathways.

Aster glehni Extract, Including Caffeoylquinic Acids as the Main Constituents, Induces PPAR β/δ-Dependent Muscle-Type Change and Myogenesis in Apolipoprotein E Knockout Mice

To probe the functions of Aster glehni (AG) extract containing various caffeoylquinic acids on dyslipidemia, obesity, and skeletal muscle-related diseases focused on the roles of skeletal muscle, we measured the levels of biomarkers involved in oxidative phosphorylation and type change of skeletal muscle in C2C12 cells and skeletal muscle tissues from apolipoprotein E knockout (ApoE KO) mice. After AG extract treatment in cell and animal experiments, western blotting, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) were used to estimate the levels of proteins that participated in skeletal muscle type change and oxidative phosphorylation. AG extract elevated protein expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), phosphorylated 5'-AMP-activated protein kinase (p-AMPK), peroxisome proliferator-activated receptor beta/delta (PPARβ/δ), myoblast determination protein 1 (MyoD), and myoglobin in skeletal muscle tissues. Furthermore, it elevated the ATP concentration. However, protein expression of myostatin was decreased by AG treatment. In C2C12 cells, increments of MyoD, myoglobin, myosin, ATP-producing pathway, and differentiation degree by AG were dependent on PPARβ/δ and caffeoylquinic acids. AG extract can contribute to the amelioration of skeletal muscle inactivity and sarcopenia through myogenesis in skeletal muscle tissues from ApoE KO mice, and function of AG extract may be dependent on PPARβ/δ, and the main functional constituents of AG are trans-5-O-caffeoylquinic acid and 3,5-O-dicaffeoylquinic acid. In addition, in skeletal muscle, AG has potent efficacies against dyslipidemia and obesity through the increase of the type 1 muscle fiber content to produce more ATP by oxidative phosphorylation in skeletal muscle tissues from ApoE KO mice.

Small extracellular vesicles from young plasma reverse age-related functional declines by improving mitochondrial energy metabolism

Recent investigations into heterochronic parabiosis have unveiled robust rejuvenating effects of young blood on aged tissues. However, the specific rejuvenating mechanisms remain incompletely elucidated. Here we demonstrate that small extracellular vesicles (sEVs) from the plasma of young mice counteract pre-existing aging at molecular, mitochondrial, cellular and physiological levels. Intravenous injection of young sEVs into aged mice extends their lifespan, mitigates senescent phenotypes and ameliorates age-associated functional declines in multiple tissues. Quantitative proteomic analyses identified substantial alterations in the proteomes of aged tissues after young sEV treatment, and these changes are closely associated with metabolic processes. Mechanistic investigations reveal that young sEVs stimulate PGC-1α expression in vitro and in vivo through their miRNA cargoes, thereby improving mitochondrial functions and mitigating mitochondrial deficits in aged tissues. Overall, this study demonstrates that young sEVs reverse degenerative changes and age-related dysfunction, at least in part, by stimulating PGC-1α expression and enhancing mitochondrial energy metabolism.

Sarcopenia in gynaecological cancers

Gynaecological cancers (GCs) comprise a group of cancers that originate in the female reproductive organs. Each GC is unique, with different signs and symptoms, risk factors and therapeutic strategies. Worldwide, the majority of GCs are still associated with high mortality rates, especially ovarian, due to difficulty in early detection. Despite numerous studies on the underlying pathophysiology, research in the field of GCs poses unique scientific and technological challenges. These challenges require a concerted multi- and inter-disciplinary effort by the clinical, scientific and research communities to accelerate the advancement of prognostic, diagnostic, and therapeutic approaches. Sarcopenia is a multifactorial disease which leads to the systemic loss of skeletal muscle mass and function. It can be caused by malignancies, as well as due to malnutrition, physical inactivity, ageing and neuromuscular, inflammatory, and/or endocrine diseases. Anorexia and systemic inflammation can shift the metabolic balance of patients with cancer cachexia towards catabolism of skeletal muscle, and hence sarcopenia. Therefore, sarcopenia is considered as an indicator of poor general health status, as well as the possible indicator of advanced cancer. There is a growing body of evidence showing the prognostic significance of sarcopenia in various cancers, including GCs. This review will outline the clinical importance of sarcopenia in patients with GCs.

Effects of Paraspinal Intramuscular Injection of Atelocollagen in Patients with Chronic Low Back Pain: A Retrospective Observational Study

Background/Objectives: Atelocollagen is used for soft tissue repair and reconstruction by replacing defective or damaged muscles, membranes, ligaments, and tendons. This study aimed to evaluate the clinical efficacy and safety of additional paraspinal intramuscular injection of atelocollagen on lumbar epidural steroid injection for reducing pain and improving functional capacity of patients with chronic low back pain (CLBP). Methods: We retrospectively enrolled 608 consecutive patients with CLBP who received lumbar epidural steroid injection with or without additional paraspinal intramuscular injection of atelocollagen. The Numerical Rating Scale and the Oswestry Disability Index were used to assess pain and functional capacity, respectively, before the procedure, and three months after the injection. Also, we analyzed the relationship between the additional paraspinal intramuscular injection of atelocollagen and the success rate. Results: Both Numerical Rating Scale and the Oswestry Disability Index scores were significantly reduced in both groups at three months after injection. However, there was a significant difference between the two groups. Furthermore, the success rate was significantly higher in the additional paraspinal intramuscular injection of atelocollagen group. Conclusions: This study's results showed that additional paraspinal intramuscular injection of atelocollagen on lumbar epidural steroid injection reduced pain and improved functional capacity for patients with CLBP. Therefore, the paraspinal intramuscular injection of atelocollagen may be a promising option for the treatment of patients with CLBP.

The Association between the Level of Ankle-Brachial Index and the Risk of Poor Physical Function in Patients with Cardiovascular Disease

AIMS

The progression of atherosclerosis and decline in physical function are poor prognostic factors in patients with cardiovascular disease (CVD). The ankle-brachial index (ABI) is a widely used indicator of the degree of progression of atherosclerosis, which may be used to identify patients with CVD who are at risk of poor physical function. This study examined the association between ABI and poor physical function in patients with CVD.

METHODS

We reviewed the data of patients with CVD who completed the ABI assessment and physical function tests (6-min walking distance, gait speed, quadriceps isometric strength, and short physical performance battery). Patients were divided into five categories according to the level of ABI, and the association between ABI and poor physical function was examined using multiple logistic regression analysis. Additionally, restricted cubic splines were used to examine the nonlinear association between ABI and physical function.

RESULTS

A total of 2982 patients (median [interquartile range] age: 71[62-78] years, 65.8% males) were included in this study. Using an ABI range of 1.11-1.20 as a reference, logistic regression analysis showed that ABI ≤ 1.10 was associated with poor physical function. The restricted cubic spline analysis showed that all physical functions increased with an increase in ABI level. The increase in physical function plateaued at an ABI level of approximately 1.1.

CONCLUSIONS

ABI may be used to identify patients with poor physical function. ABI levels below 1.1 are potentially associated with poor physical function in patients with CVD.

Navigating the nexus among thigh volume, myokine, and immunocytes in older adults with sarcopenia: A retrospective analysis in a male cohort

BACKGROUND

This study investigated the association among thigh volume features, interleukin (IL)-6, and immunocytes in the context of the older people with sarcopenia.

MATERIALS AND METHODS

This study comprised a cohort of 437 older males diagnosed with sarcopenia, and their average age of 70.41 ± 4.86 years. This study involved conducting correlation and multiple linear regression analyses to investigate the connections between thigh volume, IL-6, and immunocytes.

RESULTS

Total thigh volume (TTV) showed positive connections with thigh muscle volume (TMV), natural killer (NK) cells, and CD8 + T cells. TMV had negative associations with thigh fat volume (TFV) and IL6 but displayed positive connections with other factors. IL-6 had adverse associations with all the other variables except for TFV. NK cells showed significant positive relations with all adaptive immune cells, though showing not TFV and IL-6. The CD3+ T cells, CD4+ T cells, CD8+ T cells, and CD19+ B cells exhibited positive correlations with each other including NK cells, though showing not TFV and IL-6. In the regression analysis, TMV exhibited significant positive effects on NK cells (β = 0.304), CD3+ T cells (β = 0.182), CD4+ T cells (β = 0.109), CD8+ T cells (β = 0.226), and CD19+ B cells (β = 0.197). On the other hand, IL-6 had significant negative effects on NK cells (β = -0.292), CD3+ T cells (β = -0.352), CD4+ T cells (β = -0.184), CD8+ T cells (β = -0.387), and CD19+ B cells (β = -0.366).

CONCLUSIONS

This study found that there existed a direct association among thigh muscle with sarcopenia, myokine, and immunocytes.

SIMPLE SUMMARY

The aging process involves the immune system playing a vital role in sarcopenia development, and it is thought that myokines released by skeletal myocytes. However, the exact relationship between TMV, myokines, and immunocytes in older male adults affected by sarcopenia remains unclear. This study found that myokines observed in sarcopenia showed a negative correlation with immunocytes, while muscle mass had a positive correlation with immunocytes. In the meantime, this research delved into the use of a regression model to examine how TMV and myokines individually contribute to explaining the presence of innate and adaptive immunocytes in older individuals with sarcopenia.

Is Immune Thrombocytopenia and its Treatment Associated with Sarcopenia?

BACKGROUND

Immune thrombocytopenia (ITP) is defined as an isolated platelet count less than 100 × 109/L in the absence of other causes of thrombocytopenia. Sarcopenia is a body-wide muscular disorder with a progressive nature that leads to reduced mobility, physical disability, falls, and poor quality of life. We aimed to evaluate the frequency of objectively diagnosed sarcopenia in patients with ITP and to determine whether ITP therapies have sarcopenic effects.

METHODS

This prospective study included patients who were followed up with ITP in the hematology outpatient clinic. Patients who had received corticosteroids within 3 months were excluded. The handgrip strength test, appendicular skeletal muscle mass (ASMM), ASMM/height2 value, soft lean mass (SLM), trunk soft lean mass (SLMT), and the 6-min walking speed test were applied for muscular evaluations and physical performance assessment.

RESULTS

We included 53 patients (female/male: 73.58%/26.42%). While sarcopenia was not observed in 77.36% of ITP patients, possible sarcopenia was diagnosed in 9.43% and confirmed sarcopenia in 13.21%. Severe sarcopenia was not seen in any of the patients. Loss of muscle strength was observed in 22.64% of patients. SLM was found to be low in 92.45%.

CONCLUSION

Sarcopenia may be more frequent among patients with ITP compared to the population, and it is important to note that 92.45% of patients had low SLM and 54.72% had low SLMT. Eltrombopag therapy might be beneficial as demonstrated by higher SLM, ASMM, and ASMM/height2 values.

The impact of Helicobacter pylori infection on low skeletal muscle mass risk in Chinese women over 40: a cross-sectional analysis

Background

Sarcopenia can lead to significant personal, social, and economic burdens. The diagnosis of sarcopenia heavily relies on the identification of Low Skeletal Muscle Mass (LSMM), which is an independent predictor of frailty, disability, and increased risk of death among seniors. Women have physiologically lower levels of skeletal muscle mass than men, and female sarcopenia appears to be more influenced by menopause. They also tend to have higher body fat levels than man, which increases the risk of sarcopenia obesity. On another front, it's also recognized that humans are largely prone to Helicobacter pylori (H. pylori) infection, with global prevalence rates often surpassing 50%. Nevertheless, the interconnection between H. pylori infection and LSMM remains relatively unexplored. Hence, our study specifically targeted women as the research population and sought to explore several risk factors for LSMM. Additionally, we delved into the potential correlation between LSMM and H. pylori infection in women, hoping to gain insights into potential preventative measures or treatment options that may enhance the quality of life for women affected by sarcopenia.

Methods

We conducted a cross-sectional study among women aged over 18 years undergoing physical examination. We performed 13C-urea breath test (UBT) for diagnosis of H. pylori infection and Bioelectrical impedance analysis (BIA) for the assessment of LSMM. Logistic regression models were used to analyze the associations of H. pylori infection with LSMM.

Results

This study enrolled 1984 Chinese women who were undergoing health check-ups. A univariate logistic regression analysis did not reveal a direct correlation between H. pylori infection and LSMM among this female population (OR=1.149, 95% CI 0.904-1.459, p=0.257). Yet, upon dividing the participants into age-based subgroups, an evident link was observed between H. pylori infection and LSMM in women aged 40 or above (OR=1.381, 95%CI 1.032-1.848, p= 0.030). After adjusting for variables including Age, BMI, TP, ALK, Cre, this relationship remained statistically relevant (OR=1.514, 95%CI 1.085-2.113, p= 0.015).

Conclusions

Women who are over 40 years old and currently infected with H. pylori have an increased risk of developing LSMM. Therefore, timely treatment for H. pylori eradication is recommended for this group of women to reduce the occurrence of LSMM.

Environmental Enrichment Improves Motor Function and Muscle Transcriptome of Aged Mice

Aging results in the progressive decline of muscle strength. Interventions to maintain muscle strength may mitigate the age-related loss of physical function, thus maximizing health span. The work on environmental enrichment (EE), an experimental paradigm recapitulating aspects of an active lifestyle, has revealed EE-induced metabolic benefits mediated by a brain-fat axis across the lifespan of mice. EE initiated at 18-month of age shows a trend toward an increased mean lifespan. While previous work described EE's influences on the aging dynamics of several central-peripheral processes, its influence on muscle remained understudied. Here, the impact of EE is investigated on motor function, neuromuscular physiology, and the skeletal muscle transcriptome. EE is initiated in 20-month-old mice for a five-month period. EE mice exhibit greater relative lean mass that is associated with improved mobility and hindlimb grip strength. Transcriptomic profiling of muscle tissue reveals an EE-associated enrichment of gene expression within several metabolic pathways related to oxidative phosphorylation and the TCA cycle. Many mitochondrial-related genes-several of which participate in the electron transport chain-are upregulated. Stress-responsive signaling pathways are downregulated because of EE. The results suggest that EE improves motor function-possibly through preservation of mitochondrial function-even late in life.

The impact of diabetic polyneuropathy on toe grip strength in patients with type 2 diabetes mellitus: a cross-sectional study

Purpose

Type 2 diabetes mellitus (T2DM) and concomitant diabetic polyneuropathy (DPN) induce muscle weakness. Muscle weakness in the foot is associated with foot deformities and falls. However, factors affecting toe grip strength (TGS) are not well known. Therefore, the present study investigated factors related to TGS in patients with T2DM.

Methods

This was a cross-sectional study involving 100 patients with T2DM who were hospitalized for the treatment of T2DM and 50 healthy adults. The subjects were divided into three groups: a group of healthy subjects, a group of T2DM patients without DPN, and a group of T2DM patients with DPN. Hierarchical multiple regression analysis was performed with TGS and the TGS-to-weight ratio (TGS/Wt%) as dependent variables and with age, the presence of T2DM, and DPN as independent variables, and sex and BMI as confounders.

Results

There were no significant differences in age or sex among the three groups. In the final regression analysis, age and presence of T2DM and DPN were associated in both models with TGS and TGS/Wt% as dependent variables.

Conclusion

DPN, T2DM, and age were found to be related to TGS. The findings of this study could contribute to healthcare providers developing foot care and rehabilitation programs for diabetic patients.

Trial registration

This study was registered with UMIN-CTR (UMIN000034320) on 1 November 2018.

Age Is Just a Number: Progress and Obstacles in the Discovery of New Candidate Drugs for Sarcopenia

Sarcopenia is a disease characterized by the progressive loss of skeletal muscle mass and function that occurs with aging. The progression of sarcopenia is correlated with the onset of physical disability, the inability to live independently, and increased mortality. Due to global increases in lifespan and demographic aging in developed countries, sarcopenia has become a major socioeconomic burden. Clinical therapies for sarcopenia are based on physical therapy and nutritional support, although these may suffer from low adherence and variable outcomes. There are currently no clinically approved drugs for sarcopenia. Consequently, there is a large amount of pre-clinical research focusing on discovering new candidate drugs and novel targets. In this review, recent progress in this research will be discussed, along with the challenges that may preclude successful translational research in the clinic. The types of drugs examined include mitochondria-targeting compounds, anti-diabetes agents, small molecules that target non-coding RNAs, protein therapeutics, natural products, and repositioning candidates. In light of the large number of drugs and targets being reported, it can be envisioned that clinically approved pharmaceuticals to prevent the progression or even mitigate sarcopenia may be within reach.

A bidirectional Mendelian randomization study of sarcopenia-related traits and inflammatory bowel diseases

Background

There is increasing evidence pointing to a close relationship between sarcopenia and inflammatory bowel disease. However, it remains unclear whether or in which direction causal relationships exist, because these associations could be confounded.

Methods

We conducted a two-sample bidirectional mendelian randomization analysis using data from European genome-wide association studies of the appendicular lean mass(n = 450,243), walking pace(n = 459,915), grip strength (left hand, n = 461,026; right hand, n = 461,089), inflammatory bowel disease (25,042 patients and 34,915 controls), ulcerative colitis (12,366 patients and 33,609 controls), and Crohn's disease (12,194 patients and 28,072 controls) to investigate the causal relationship between sarcopenia-related traits and inflammatory bowel disease and its subtypes on each other. The inverse-variance weighted method was used as the primary analysis method to assess the causality, and a comprehensive sensitivity test was conducted.

Results

Genetically predicted appendicular lean mass was significantly associated with inflammatory bowel disease (OR = 0.916, 95%CI: 0.853-0.984, P = 0.017), ulcerative colitis (OR =0.888, 95%CI: 0.813-0.971, P = 0.009), and Crohn's disease (OR = 0.905, 95%CI: 0.820-0.999, P = 0.049). Similar results also revealed that the usual walking pace was causally associated with Crohn's disease (OR = 0.467, 95%CI: 0.239-0.914, P = 0.026). Reverse mendelian randomization analysis results found that genetic susceptibility to inflammatory bowel disease, and Crohn's disease were associated with lower appendicular lean mass. A series of sensitivity analyses ensured the reliability of the present research results.

Conclusion

The mendelian randomization study supports a bidirectional causality between inflammatory bowel disease, Crohn's disease and appendicular lean mass, but no such bidirectional causal relationship was found in ulcerative colitis. In addition, genetically predicted usual walking pace may reduce the risk of Crohn's disease. These findings have clinical implications for sarcopenia and inflammatory bowel disease management.

Evaluation of sex-based differences in resistance exercise training-induced changes in muscle mass, strength, and physical performance in healthy older (≥60 y) adults: A systematic review and meta-analysis

The objective of this systematic review and meta-analysis was to determine if there are sex-based differences in adaptations to resistance exercise training in healthy older adults. Following the screening process, data from 36 studies comparing older males and females (602 males; 703 females; ≥60 years of age) for changes in skeletal muscle size, muscle strength, and/or physical performance following the same resistance exercise training intervention were extracted. Mean study quality was 16/29 (modified Downs and Black checklist), considered moderate quality. Changes in absolute upper-body (Effect Size [ES] = 0.81 [95% CI 0.54, 1.09], P < 0.001), and lower-body (ES = 0.40 [95% CI 0.24, 0.56], P < 0.001) strength were greater in older males than females. Alternatively, changes in relative upper-body (ES = -0.46 [95% CI -0.77, -0.14], P < 0.01), and lower-body (ES = -0.24 [95% CI -0.42, -0.06], P < 0.01) strength were greater in older females than males. Changes in absolute, but not relative, whole-body fat-free mass (ES = 0.18 [95% CI 0.04, 0.33], P < 0.05) were greater in older males than females. There were no sex-based differences for absolute or relative changes in limb muscle size, muscle fiber size, or physical performance.

Methods and research progress in the construction of animal models of osteosarcopenia: a scoping review

Background

Osteosarcopenia(OS) is a significant health concern resulting from the ageing process. Currently, as the population grows older, the prevalence of OS, a disease that entails the synchronous degeneration of muscles and bones, is mounting. This poses a serious threat to the health of the elderly while placing an enormous burden on social care. In order to comprehend the pathological mechanism of OS and develop clinical drugs, it is pertinent to construct an efficient animal model of OS. To investigate the modeling techniques of diverse experimental models of OS and elucidate their respective benefits and drawbacks, with the purpose of furnishing a theoretical foundation to advance experimental research on OS.

Methods

We searched PubMed, Embase database, China Knowledge Network, Wanfang data platform and Vipshop journal platform databases from 2000 through to September 1, 2023. We included animal studies on sarcopenia or osteoporosis or osteosarcopenia or sarcopenia-osteoporosis, modeling methods for osteosarcopenia. Two independently screened study abstracts and full reports and complete data extraction.

Results

Eventually, Of 112, 106 citations screened. 4938 underwent full-text review and 38 met the inclusion criteria. we reviewed and analyzed the literature and categorized the animal models of OS into the following five categories: Aging OS models; Hormonal deficiency model of OS;Chemical injection to induce OS;Disuse OS models and Genetic engineering OS models.

Conclusion

This review outlines animal modeling approaches for OS, providing a comprehensive summary of their advantages and disadvantages. The different models were evaluated and selected based on their respective strengths and weaknesses to enable higher quality research outcomes in various research directions. The most widely used and established approach is considered to be the ageing and chemical injection OS model, which has the advantages of excellent reproducibility and low cost.

The translational potential of this article

To gain a profound comprehension of the pathological mechanism of OS and to devise efficacious clinical treatments, it is imperative to establish a viable laboratory animal model of OS. This article surveys various modeling techniques assessing their benefits, drawbacks and areas of applicability while predominantly employing mice as the primary model animal. Additionally, the evaluation indicators of OS models are briefly described.

Multidisciplinary approach to sarcopenia: a narrative review

Sarcopenia is a condition in which muscle mass and strength are decreased and muscle function is impaired. It is an indicator of frailty and loss of independence in older adults. It is also associated with increased physical disability, which increases the risk of falls. As a multifactorial disease, sarcopenia is caused by a combination of factors including aging, hormonal changes, nutritional deficiencies, and physical inactivity. Understanding the underlying pathophysiology of sarcopenia and identifying its different causes is critical to developing effective prevention and treatment strategies. This review summarizes the pathophysiology, consequences, diagnostic methods, and multidisciplinary approaches to sarcopenia.

Sarcopenia in patients with rheumatic musculoskeletal diseases

AIM

To investigate the impact of high-dose glucocorticoid therapy on sarcopenia in hospitalized patients with rheumatic musculoskeletal diseases (RMDs).

METHODS

We included patients with RMDs who were hospitalized between 2020 and 2022 for remission induction treatment and collected information on skeletal mass index (SMI) before high-dose glucocorticoid therapy and 1 month later. We divided the patients into 2 groups according to the progression of sarcopenia, defined as a >10% decrease in SMI, and compared their clinical characteristics.

RESULTS

Forty-nine patients were included in this analysis. The mean age was 53.3 years, 73.5% were female, and the mean SMI was 5.3 kg/m2 . Before treatment, 83.7% had already met the definition of sarcopenia, and 57.1% experienced further sarcopenia progression after 1 month of high-dose glucocorticoid treatment. Patients with sarcopenia progression were predominantly male (P = 0.025), had a higher body weight (P = 0.048), and showed a higher SMI than those without sarcopenia at baseline (P = 0.008). Multivariable analysis revealed that body weight increase from 0 to week 1 of high-dose glucocorticoid treatment was associated with sarcopenia progression (odds ratio: 0.22, 95% CI: 0.04-0.61, P = 0.007) with a cut-off of -1.8 kg. During a mean observation period of 30.2 days, the incidence of infection was significantly higher in patients with progressive sarcopenia (P = 0.042).

CONCLUSIONS

One-month hospitalization with high-dose glucocorticoid therapy is associated with sarcopenia progression in patients with RMDs. An early decrease in body weight can be used to predict muscle volume loss.

Relationships between anthropometric and body composition characteristics and age in Polish women over 60 as affected by their socioeconomic and health status and physical activity levels

Background: Little is known about changes in anthropometric and body composition (A&BC) characteristics during the aging process. Research indicates that body composition can be linked with socioeconomic status (SES), health status (HS), and physical activity (PA) levels. Aim: The aim of this study was to evaluate age-related changes in A&BC characteristics in female seniors aged 60+ in view of their SES, HS, and PA levels. Methods: The survey was conducted in November and December 2022 on a total of 661 female seniors. A questionnaire survey was conducted to obtain information about the participants' socioeconomic status (chronic diseases, health status, marital status, membership in social organizations, financial status, place of residence, education). The respondents' PA levels were assessed with the International Physical Activity Questionnaire (IPAQ), and their A&BC characteristics were determined in a bioelectrical impedance analysis with the InBody 270 body composition analyzer. The relationships between A&BC characteristics and age were evaluated based on the values of the Pearson correlation coefficient (r). Results: The mean values of Percent Body Fat (PBF), Body Mass Index (BMI), and the waist-hip ratio (WHR) were relatively high (37.2%, 28.5 kg/m², and 0.8, respectively) and indicative of overweight and gynoid obesity. A higher number of significant negative correlations between A&BC characteristics and age were observed in seniors with lower values of SES, HS, and PA, which points to more rapid involutional changes in this group of respondents. A segmental analysis also revealed significantly lower values of fat-free mass (FFM) and body fat mass (BFM) (both indicators were calculated in percentage and kg), in particular in the upper limbs, in women with lower SES, HS, and PA levels. Conclusion: Environmental factors, including biological, physiological, environmental, psychological, behavioral, and social factors, are significantly associated with aging in women. Age-related changes in A&BC characteristics tend to proceed more rapidly in female seniors with low values of SES and HE and insufficient PA levels.

Pathogenesis, Intervention, and Current Status of Drug Development for Sarcopenia: A Review

Sarcopenia refers to the loss of muscle strength and mass in older individuals and is a major determinant of fall risk and impaired ability to perform activities of daily living, often leading to disability, loss of independence, and death. Owing to its impact on morbidity, mortality, and healthcare expenditure, sarcopenia in the elderly has become a major focus of research and public policy debates worldwide. Despite its clinical importance, sarcopenia remains under-recognized and poorly managed in routine clinical practice, partly owing to the lack of available diagnostic testing and uniform diagnostic criteria. Since the World Health Organization and the United States assigned a disease code for sarcopenia in 2016, countries worldwide have assigned their own disease codes for sarcopenia. However, there are currently no approved pharmacological agents for the treatment of sarcopenia; therefore, interventions for sarcopenia primarily focus on physical therapy for muscle strengthening and gait training as well as adequate protein intake. In this review, we aimed to examine the latest information on the epidemiology, molecular mechanisms, interventions, and possible treatments with new drugs for sarcopenia.

Longitudinal transcriptomic analysis of mouse sciatic nerve reveals pathways associated with age-related muscle pathology

BACKGROUND

Sarcopenia, the age-associated decline in skeletal muscle mass and strength, has long been considered a disease of muscle only, but accumulating evidence suggests that sarcopenia could originate from the neural components controlling muscles. To identify early molecular changes in nerves that may drive sarcopenia initiation, we performed a longitudinal transcriptomic analysis of the sciatic nerve, which governs lower limb muscles, in aging mice.

METHODS

Sciatic nerve and gastrocnemius muscle were obtained from female C57BL/6JN mice aged 5, 18, 21 and 24 months old (n = 6 per age group). Sciatic nerve RNA was extracted and underwent RNA sequencing (RNA-seq). Differentially expressed genes (DEGs) were validated using quantitative reverse transcription PCR (qRT-PCR). Functional enrichment analysis of clusters of genes associated with patterns of gene expression across age groups (adjusted P-value < 0.05, likelihood ratio test [LRT]) was performed. Pathological skeletal muscle aging was confirmed between 21 and 24 months by a combination of molecular and pathological biomarkers. Myofiber denervation was confirmed with qRT-PCR of Chrnd, Chrng, Myog, Runx1 and Gadd45ɑ in gastrocnemius muscle. Changes in muscle mass, cross-sectional myofiber size and percentage of fibres with centralized nuclei were analysed in a separate cohort of mice from the same colony (n = 4-6 per age group).

RESULTS

We detected 51 significant DEGs in sciatic nerve of 18-month-old mice compared with 5-month-old mice (absolute value of fold change > 2; false discovery rate [FDR] < 0.05). Up-regulated DEGs included Dbp (log2 fold change [LFC] = 2.63, FDR < 0.001) and Lmod2 (LFC = 7.52, FDR = 0.001). Down-regulated DEGs included Cdh6 (LFC = -21.38, FDR < 0.001) and Gbp1 (LFC = -21.78, FDR < 0.001). We validated RNA-seq findings with qRT-PCR of various up- and down-regulated genes including Dbp and Cdh6. Up-regulated genes (FDR < 0.1) were associated with the AMP-activated protein kinase signalling pathway (FDR = 0.02) and circadian rhythm (FDR = 0.02), whereas down-regulated DEGs were associated with biosynthesis and metabolic pathways (FDR < 0.05). We identified seven significant clusters of genes (FDR < 0.05, LRT) with similar expression patterns across groups. Functional enrichment analysis of these clusters revealed biological processes that may be implicated in age-related changes in skeletal muscles and/or sarcopenia initiation including extracellular matrix organization and an immune response (FDR < 0.05).

CONCLUSIONS

Gene expression changes in mouse peripheral nerve were detected prior to disturbances in myofiber innervation and sarcopenia onset. These early molecular changes we report shed a new light on biological processes that may be implicated in sarcopenia initiation and pathogenesis. Future studies are warranted to confirm the disease modifying and/or biomarker potential of the key changes we report here.

Protein posttranslational modifications in health and diseases: Functions, regulatory mechanisms, and therapeutic implications

Protein posttranslational modifications (PTMs) refer to the breaking or generation of covalent bonds on the backbones or amino acid side chains of proteins and expand the diversity of proteins, which provides the basis for the emergence of organismal complexity. To date, more than 650 types of protein modifications, such as the most well-known phosphorylation, ubiquitination, glycosylation, methylation, SUMOylation, short-chain and long-chain acylation modifications, redox modifications, and irreversible modifications, have been described, and the inventory is still increasing. By changing the protein conformation, localization, activity, stability, charges, and interactions with other biomolecules, PTMs ultimately alter the phenotypes and biological processes of cells. The homeostasis of protein modifications is important to human health. Abnormal PTMs may cause changes in protein properties and loss of protein functions, which are closely related to the occurrence and development of various diseases. In this review, we systematically introduce the characteristics, regulatory mechanisms, and functions of various PTMs in health and diseases. In addition, the therapeutic prospects in various diseases by targeting PTMs and associated regulatory enzymes are also summarized. This work will deepen the understanding of protein modifications in health and diseases and promote the discovery of diagnostic and prognostic markers and drug targets for diseases.

Multiscale network analysis identifies potential receptors for SARS-CoV-2 and reveals their tissue-specific and age-dependent expression

The coronavirus disease 2019 (COVID-19) pandemic has affected tens of millions of individuals and caused hundreds of thousands of deaths worldwide. Here, we present a comprehensive, multiscale network analysis of the transcriptional response to the virus. In particular, we focused on key regulators, cell receptors, and host processes that were hijacked by the virus for its advantage. ACE2-controlled processes involved CD300e (a TYROBP receptor) as a key regulator and the activation of IL-2 pro-inflammatory cytokine signaling. We further investigated the age dependency of such receptors in different tissues. In summary, this study provides novel insights into the gene regulatory organization during the SARS-CoV-2 infection and the tissue-specific, age-dependent expression of the cell receptors involved in COVID-19.

Review article: Putting some muscle into sarcopenia-the pathogenesis, assessment and clinical impact of muscle loss in patients with inflammatory bowel disease

BACKGROUND

Sarcopenia, a loss of skeletal muscle mass or function, affects up to 50% of patients with inflammatory bowel disease (IBD) and is associated with poor clinical outcomes including increased hospitalizations, need for surgery and post-operative complications. Despite the high prevalence and clinical significance of sarcopenia in patients with IBD, few patients undergo routine muscle evaluation.

AIM

The goal of this study was to review the mechanisms of sarcopenia in patients with IBD and understand novel modalities to assess and treat impaired muscle mass or function.

METHODS

Pubmed and Cochrane databases were searched including articles published up to February 2023 utilizing the following keywords: "inflammatory bowel disease", "IBD", "Crohn's disease", "ulcerative colitis", "sarcopenia", "myosteatosis", "muscle health", and "frailty".

RESULTS

The pathogenesis of sarcopenia in IBD is not well defined, however, there is evidence supporting the role of malabsorption, reduced protein intake, chronic inflammation, dysbiosis, decreased physical activity, medication effects and hormone signaling from visceral adiposity. Traditional sarcopenia assessment techniques include direct measurements on cross sectional imaging. However, given the time, cost and radiation exposure associated with cross sectional imaging, new bedside tools are now available to estimate muscle mass, including assessment of grip strength, mid upper arm circumference and body composition utilizing bioelectrical impedance analysis. In addition, novel biomarkers for assessing muscle mass and techniques utilizing point of care ultrasound have been proposed to make sarcopenia evaluation more streamlined in the IBD clinic.

CONCLUSION

Sarcopenia is associated with poor clinical outcomes independent of IBD activity and therefore muscle health should be assessed in all IBD patients at routine intervals. Future studies to better our understanding of the pathophysiology as well as most effective management of sarcopenia in IBD will help guide clinical care and reduce disease related complications.

The Potential Modulatory Effects of Exercise on Skeletal Muscle Redox Status in Chronic Kidney Disease

Chronic Kidney Disease (CKD) is a global health burden with high mortality and health costs. CKD patients exhibit lower cardiorespiratory and muscular fitness, strongly associated with morbidity/mortality, which is exacerbated when they reach the need for renal replacement therapies (RRT). Muscle wasting in CKD has been associated with an inflammatory/oxidative status affecting the resident cells' microenvironment, decreasing repair capacity and leading to atrophy. Exercise may help counteracting such effects; however, the molecular mechanisms remain uncertain. Thus, trying to pinpoint and understand these mechanisms is of particular interest. This review will start with a general background about myogenesis, followed by an overview of the impact of redox imbalance as a mechanism of muscle wasting in CKD, with focus on the modulatory effect of exercise on the skeletal muscle microenvironment.

The syndromic triad of COVID-19, type 2 diabetes, and malnutrition

The coronavirus disease 2019 (COVID-19) pandemic challenges our collective understanding of transmission, prevention, complications, and clinical management of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Risk factors for severe infection, morbidity, and mortality are associated with age, environment, socioeconomic status, comorbidities, and interventional timing. Clinical investigations report an intriguing association of COVID-19 with diabetes mellitus and malnutrition but incompletely describe the triphasic relationship, its mechanistic pathways, and potential therapeutic approaches to address each malady and their underlying metabolic disorders. This narrative review highlights common chronic disease states that interact epidemiologically and mechanistically with the COVID-19 to create a syndromic phenotype-the COVID-Related Cardiometabolic Syndrome-linking cardiometabolic-based chronic disease drivers with pre-, acute, and chronic/post-COVID-19 disease stages. Since the association of nutritional disorders with COVID-19 and cardiometabolic risk factors is well established, a syndromic triad of COVID-19, type 2 diabetes, and malnutrition is hypothesized that can direct, inform, and optimize care. In this review, each of the three edges of this network is uniquely summarized, nutritional therapies discussed, and a structure for early preventive care proposed. Concerted efforts to identify malnutrition in patients with COVID-19 and elevated metabolic risks are needed and can be followed by improved dietary management while simultaneously addressing dysglycemia-based chronic disease and malnutrition-based chronic disease.

Sarcopenia as a risk factor of progression-free survival in patients with metastases: a systematic review and meta-analysis

BACKGROUND

Metastasis of cancer causes more than 90% of cancer deaths and is severely damaging to human health. In recent years, several studies have linked sarcopenia to shorter survival in patients with metastatic cancer. Several predictive models exist to predict mortality in patients with metastatic cancer, but have reported limited accuracy.

METHODS

We systematically searched Medline, EMBASE, and the Cochrane Library for articles published on or before October 14, 2022. Pooled Hazard Ratio (HR) estimates with 95% confidence intervals (CIs) were calculated using a random effects model. The primary outcome was an increased risk of death or tumor progression in patients with metastatic cancer, which is expressed as progression-free survival (PFS). In addition, we performed subgroup analyses and leave-one-out sensitivity analyses to explore the main sources of heterogeneity and the stability of the results.

RESULTS

Sixteen retrospective cohort studies with 1,675 patients were included in the 888 papers screened. The results showed that sarcopenia was associated with lower progression-free survival (HR = 1.56, 95% CI = 1.19-2.03, I2 = 76.3%, P < 0.001). This result was further confirmed by trim-and-fill procedures and leave-one-out sensitivity analysis.

CONCLUSIONS

This study suggests that sarcopenia may be a risk factor for reduced progression-free survival in patients with metastatic cancer. Further studies are still needed to explain the reason for this high heterogeneity in outcome.

TRIAL REGISTRATION

CRD42022325910.

Interaction between sarcopenia and nonalcoholic fatty liver disease

Sarcopenia and nonalcoholic fatty liver disease (NAFLD) are common health problems related to aging. Despite the differences in their diagnostic methods, several cross-sectional and longitudinal studies have revealed the close link between sarcopenia and NAFLD. Sarcopenia and NAFLD are linked by several shared pathogenetic mechanisms, including insulin resistance, hormonal imbalance, systemic inflammation, myostatin and adiponectin dysregulation, nutritional deficiencies, and physical inactivity, thus implicating a bidirectional relationship between sarcopenia and NAFLD. However, there is not sufficient data to support a direct causal relationship between sarcopenia and NAFLD. Moreover, it is currently difficult to conclude whether sarcopenia is a risk factor for nonalcoholic steatohepatitis (NASH) or is a consequence of NASH. Therefore, this review intends to touch on the shared common mechanisms and the bidirectional relationship between sarcopenia and NAFLD.

Prediabetes is associated with loss of appendicular skeletal muscle mass and sarcopenia

Background

Decreasing mass and metabolism in skeletal muscle are associated with increasing insulin resistance (IR) and type 2 diabetes mellitus (T2DM). The causal relation between sarcopenia and abnormal glucose metabolism may be bidirectional. This investigation is aimed to explore the detailed correlation between pre-diabetes and sarcopenia in United States (US) adults.

Methods

A total of 22,482 adults aged ≥20 years in the National Health and Nutrition Examination Survey (NHANES) were included. Generalized linear models were conducted to examine associations between diabetes status, serum glucose, glycohemoglobin (HbA1c), and sarcopenia. Generalized additive models and smooth fitting curves were used to examine the non-linear relationship between HbA1c and ASM_BMI. Sarcopenia was defined as ASM_BMI (appendicular skeletal muscle mass/body mass index) < 0.789 for males, and <0.512 for females based on the cut-off values of the Foundation for the National Institutes of Health (FNIH) Sarcopenia Project.

Results

After fully adjusting for multiple covariates, sarcopenia was directly correlated with pre-diabetes [OR (95%CI) = 1.230 (1.057, 1.431), p = 0.008] and T2DM [OR (95%CI) = 2.106 (1.625, 2.729), p < 0.001]. In non-T2DM population, HbA1c was negatively correlated with ASM_BMI [β (95%CI) = -0.009 (-0.013, -0.005), p < 0.001]. The correlations only persisted in males. Furthermore, in male non-T2DM population, the association of HbA1c and ASM_BMI presents an inverted U-shape curve with an inflection point of HbA1c 5.2%.

Conclusion

Pre-diabetes is associated with increased risk of sarcopenia. HbA1c is an independent risk factor for loss of appendicular skeletal muscle mass and sarcopenia when HbA1c greater than 5.2% in the male non-T2DM population.

Vitamin D Deficiency in Both Oral and Systemic Manifestations in SARS-CoV-2 Infection: Updated Review

The specialized literature emphasizes the fact that vitamin D has a potentially beneficial effect in the context of the current COVID-19 pandemic. The purpose of this article is to highlight the role of vitamin D, both prophylactic and curative, in the treatment of patients diagnosed with COVID-19. Even though its relevance is still unknown and causes various controversies, there is currently no specific treatment for patients diagnosed with COVID-19. There are various prevention strategies with new vaccination schedules, but additional randomized and clinical trials are still needed to combat this pandemic. In addition to the systemic manifestations of SARS-CoV-2 infection, oral manifestations of this disease have also been described in the literature. The etiology of oral manifestations associated with COVID-19 infection and vitamin D deficiency remains controversial. In the present studies, oral manifestations such as salivary gland infections, aphthae, erythema, gingivitis, ulcers, etc. have been reported. This is a new topic, and the prevalence of manifestations is described in only a few studies, which is inconsistent with the number of COVID-19 cases reported since the beginning of the pandemic. The clinical symptomatology in patients with current COVID-19 infection is polymorphic. Whether the oral manifestation is directly caused by SARS-CoV-2 or a secondary manifestation remains an important topic to analyze and discuss.

Organotypic cultures as aging associated disease models

Aging remains a primary risk factor for a host of diseases, including leading causes of death. Aging and associated diseases are inherently multifactorial, with numerous contributing factors and phenotypes at the molecular, cellular, tissue, and organismal scales. Despite the complexity of aging phenomena, models currently used in aging research possess limitations. Frequently used in vivo models often have important physiological differences, age at different rates, or are genetically engineered to match late disease phenotypes rather than early causes. Conversely, routinely used in vitro models lack the complex tissue-scale and systemic cues that are disrupted in aging. To fill in gaps between in vivo and traditional in vitro models, researchers have increasingly been turning to organotypic models, which provide increased physiological relevance with the accessibility and control of in vitro context. While powerful tools, the development of these models is a field of its own, and many aging researchers may be unaware of recent progress in organotypic models, or hesitant to include these models in their own work. In this review, we describe recent progress in tissue engineering applied to organotypic models, highlighting examples explicitly linked to aging and associated disease, as well as examples of models that are relevant to aging. We specifically highlight progress made in skin, gut, and skeletal muscle, and describe how recently demonstrated models have been used for aging studies or similar phenotypes. Throughout, this review emphasizes the accessibility of these models and aims to provide a resource for researchers seeking to leverage these powerful tools.

Sarcopenia in urologic oncology: Identification and strategies to improve patient outcomes

Sarcopenia is the loss of muscle mass and function related to aging, undereating, disease conditions, or inactivity. Pre-existing sarcopenia diminishes the functional reserve of patients with cancer which increases their risk for frailty, cancer cachexia, and worse outcomes from treatments. The pathogenesis of sarcopenia is multi-factorial: opening opportunities for clinicians to work across disciplines to improve patient outcomes and quality of life. The purpose of this essay is to describe sarcopenia, discuss clinical screening and assessment for sarcopenia, and highlight potential interventions to manage sarcopenia in the urologic oncology population.

Sarcopenia and Frailty in Heart Failure: Is There a Biomarker Signature?

PURPOSE OF REVIEW

Sarcopenia and frailty are common in patients with heart failure (HF) and are strongly associated with prognosis. This review aims to examine promising biomarkers that can guide physicians in identifying sarcopenia and frailty in HF.

RECENT FINDINGS

Traditional biomarkers including C-reactive protein, aminotransaminase, myostatin, and urinary creatinine as well as novel biomarkers including microRNAs, suppression of tumorigenicity 2 (ST2), galectin-3, and procollagen type III N-terminal peptide may help in predicting the development of sarcopenia and frailty in HF patients. Among those biomarkers, aminotransferase, urinary creatinine, and ST2 predicted the prognosis in HF patients with sarcopenia and frailty. This review outlines the current knowledge of biomarkers that are considered promising for diagnosing sarcopenia and frailty in HF. The listed biomarkers might support the diagnosis, prognosis, and therapeutic decisions for sarcopenia and frailty in HF patients.

Frailty and Sarcopenia: Impact on Outcomes Following Elective Degenerative Lumbar Spine Surgery

STUDY DESIGN

This is a retrospective review of prospectively collected data.

OBJECTIVE

The aim was to evaluate the impact of frailty and sarcopenia on outcomes after lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

Elderly patients are commonly diagnosed with degenerative spine disease requiring surgical intervention. Frailty and sarcopenia result from age-related decline in physiological reserve and can be associated with complications after elective spine surgery. Little is known about the impact of these factors on patient-reported outcomes (PROs).

METHODS

Patients older than 70 years of age undergoing elective lumbar spine surgery were included. The modified 5-item frailty index (mFI-5) was calculated. Sarcopenia was defined using total psoas index, which is obtained by dividing the mid L3 total psoas area by VB area (L3-TPA/VB). PROs included Oswestry disability index (ODI), EuroQual-5D (EQ-5D), numeric rating scale (NRS)-back pain, NRS leg pain (LP), and North American Spine Society (NASS) at postoperative 12 months. Clinical outcomes included length of stay (LOS), 90-day readmission and complications. Univariate and multivariable regression analyses were performed.

RESULTS

Total 448 patients were included. The mean mFI-5 index was 1.6±1.0 and mean total psoas index was 1.7±0.5. There was a significant improvement in all PROs from baseline to 12 months ( P <0.0001). After adjusting for age, body mass index, smoking status, levels fused, and baseline PROs, higher mFI-5 index was associated with higher 12-month ODI ( P <0.001), lower 12-month EQ-5D ( P =0.001), higher NRS-L P ( P =0.039), and longer LOS ( P =0.007). Sarcopenia was not associated with 12-month PROs or LOS. Neither sarcopenia or mFI-5 were associated with 90-day complication and readmission.

CONCLUSIONS

Elderly patients demonstrate significant improvement in PROs after elective lumbar spine surgery. Frailty was associated with worse 12 months postoperative ODI, EQ-5D, NRS-LP scores, and longer hospital stay. While patients with sarcopenia can expect similar outcomes compared with those without, the mFI-5 should be considered preoperatively in counseling patients regarding expectations for disability, health-related quality of life, and leg pain outcomes after elective lumbar spine surgery.

LEVEL OF EVIDENCE

3.

Body composition and level of physical activity of elderly people living in north-eastern Poland associated with socioeconomic factors

Introduction: Studies conducted in various regions of the world have indicated that physical activity level, body composition and socioeconomic variables can be associated. Therefore, the objective of this study was to determine whether socioeconomic factors are associated with level of physical activity and differences in the body composition of elderly people living in north-eastern Poland. Materials and Methods: The study involved 774 older residents (60 years or more). Physical activity levels were measured with the International Physical Activity Questionnaire. The respondents’ body composition was determined with an InBody 270 analyser. Pairs of means were compared with Student’s t-test; more than two means were compared with one-way ANOVA; and proportions were compared with the chi-square test. Statistical significance was defined as p≤0.05. Results: The marital status of men and women was significantly associated with differences in physical activity level and body composition. The place of residence and level of education of women (but not of men), were also significantly associated with differences in body composition. Age and material situation were not significantly associated with differences in body composition and physical activity level. Conclusion: The mean values of parameters of body composition in the surveyed group exceeded the norms. The level of physical activity of the subjects is at a sufficient level, but in the case of women it depends on socio-economic characteristics. Therefore, there is a need to find effective ways to support older adults in maintaining (or increase) their physical activity with a particular focus on women.

Gestational and childhood phthalate exposures and adolescent body composition: The HOME study

BACKGROUND

Early life phthalate exposures may disrupt metabolism but results from human studies are inconsistent and few have examined body composition during adolescence. We investigated associations of gestational and childhood urinary phthalate biomarker concentrations with body composition at age 12 years.

METHODS

We used data from 206 mother-child pairs in a prospective pregnancy and birth cohort enrolled in Cincinnati, OH from 2003 to 2006. We measured nine phthalate metabolites in spot urine samples collected twice from mothers during pregnancy and up to seven times from children at 1, 2, 3, 4, 5, 8, and 12 years. At age 12 years, we assessed fat and lean mass of the whole body and android and gynoid subregions, and visceral fat area with dual x-ray absorptiometry, and calculated android to gynoid %fat ratio and age- and sex-standardized fat and lean mass index z-scores. Using a multiple informant model, we estimated covariate-adjusted associations between urinary phthalate biomarker concentrations at each time period and outcomes at age 12 years. We assessed effect measure modification by child sex using stratified models.

RESULTS

Generally, urinary mono-benzyl phthalate (MBzP) concentrations were modestly associated with lower fat and lean mass. Each 10-fold increase in urinary MBzP concentrations during gestation and at ages 5 and 8 years was associated with a -0.34 (95%CI: -0.72, 0.05), -0.44 (95% CI: -0.83, -0.05), and -0.35 (95% CI: -0.71, 0.00) z-score difference in lean body mass index, respectively. Urinary monoethyl phthalate, mono-(3-carboxypropyl) phthalate, and summed di(2-ethylhexyl) phthalate metabolites were associated with greater lean mass at some exposure periods. Slightly weaker but similar patterns of association were found with other body composition measures; associations did not differ by child sex.

CONCLUSION

While most associations were weak, exposure to certain phthalates during gestation and childhood may be associated with adolescent body composition, particularly lean mass.

A Review of Sarcopenia Pathophysiology, Diagnosis, Treatment and Future Direction

Sarcopenia is a progressive and generalized loss of skeletal muscle mass and function. The prevalence of sarcopenia was reported to be up to 29% in older persons in the community healthcare setting. Sarcopenia diagnosis is confirmed by the presence of low muscle mass plus low muscle strength or low physical performance. Sarcopenia management options include non-pharmacological and pharmacological approaches. Non-pharmacological approaches include resistance exercise and adequate nutrition. Of the two, resistance exercise is the standard non-pharmacological treatment approach for sarcopenia with significant positive evidence. Some dietary approaches such as adequate intake of protein, vitamin D, antioxidant nutrients, and long-chain polyunsaturated fatty acid have been shown to have positive effects against sarcopenia. Currently, no specific drugs have been approved by the Food and Drug Administration for the treatment of sarcopenia. However, several agents, including growth hormone, anabolic or androgenic steroids, selective androgenic receptor modulators, protein anabolic agents, appetite stimulants, myostatin inhibitors, activating II receptor drugs, β-receptor blockers, angiotensin-converting enzyme inhibitors, and troponin activators, are recommended and have been shown to have variable efficacy. Future research should focus on sarcopenia biological pathway and improved diagnostic approaches such as biomarkers for early detection, development of consistently pre-eminent treatment methods for severe sarcopenia patients, and establishing sensitive measures for predicting sarcopenia treatment response.

High Intensity Interval Training: A Potential Method for Treating Sarcopenia

Sarcopenia, an age-related disease characterized by loss of muscle strength and muscle mass, has attracted the attention of medical experts due to its severe morbidity, low living quality, high expenditure of health care, and mortality. Traditionally, persistent aerobic exercise (PAE) is considered as a valid way to attenuate muscular atrophy. However, nowadays, high intensity interval training (HIIT) has emerged as a more effective and time-efficient method to replace traditional exercise modes. HIIT displays comprehensive effects on exercise capacity and skeletal muscle metabolism, and it provides a time-out for the recovery of cardiopulmonary and muscular functions without causing severe adverse effects. Studies demonstrated that compared with PAE, HIIT showed similar or even higher effects in improving muscle strength, enhancing physical performances and increasing muscle mass of elder people. Therefore, HIIT might become a promising way to cope with the age-related loss of muscle mass and muscle function. However, it is worth mentioning that no study of HIIT was conducted directly on sarcopenia patients, which is attributed to the suspicious of safety and validity. In this review, we will assess the effects of different training parameters on muscle and sarcopenia, summarize previous papers which compared the effects of HIIT and PAE in improving muscle quality and function, and evaluate the potential of HIIT to replace the status of PAE in treating old people with muscle atrophy and low modality; and point out drawbacks of temporary experiments. Our aim is to discuss the feasibility of HIIT to treat sarcopenia and provide a reference for clinical scientists who want to utilize HIIT as a new way to cope with sarcopenia.

Gastric Mobility and Gastrointestinal Hormones in Older Patients with Sarcopenia

Sarcopenia has serious clinical consequences and poses a major threat to older people. Gastrointestinal environmental factors are believed to be the main cause. The aim of this study was to describe the relationship between sarcopenia and gastric mobility and to investigate the relationship between sarcopenia and the concentration of gastrointestinal hormones in older patients. Patients aged ≥ 75 years were recruited for this prospective study from August 2018 to February 2019 at the emergency department. The enrolled patients were tested for sarcopenia. Gastric emptying scintigraphy was conducted, and laboratory tests for cholecystokinin(CCK), glucagon-like peptide-1 (GLP-1), peptide YY (PYY), nesfatin, and ghrelin were performed during the fasting period. We enrolled 52 patients with mean age of 86.9 years, including 17 (32.7%) patients in the non-sarcopenia group, 17 (32.7%) patients in the pre-sarcopenia group, and 18 (34.6%) in the sarcopenia group. The mean gastric emptying half-time had no significant difference among three groups. The sarcopenia group had significantly higher fasting plasma concentrations of CCK, GLP-1, and PYY. We concluded that the older people with sarcopenia had significantly higher plasma concentrations of CCK, GLP-1, and PYY. In the elderly population, anorexigenic gastrointestinal hormones might have more important relationships with sarcopenia than orexigenic gastrointestinal hormones.

The Role of Oxidative Stress in Skeletal Muscle Myogenesis and Muscle Disease

The contractile activity, high oxygen consumption and metabolic rate of skeletal muscle cause it to continuously produce moderate levels of oxidant species, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS). Under normal physiological conditions, there is a dynamic balance between the production and elimination of ROS/RNS. However, when the oxidation products exceed the antioxidant defense capacity, the body enters a state of oxidative stress. Myogenesis is an important process to maintain muscle homeostasis and the physiological function of skeletal muscle. Accumulating evidence suggests that oxidative stress plays a key role in myogenesis and skeletal muscle physiology and pathology. In this review, we summarize the sources of reactive oxygen species in skeletal muscle and the causes of oxidative stress and analyze the key role of oxidative stress in myogenesis. Then, we discuss the relationship between oxidative stress and muscle homeostasis and physiopathology. This work systematically summarizes the role of oxidative stress in myogenesis and muscle diseases and provides targets for subsequent antioxidant therapy and repair of inflammatory damage in noninflammatory muscle diseases.

Significance of a decrease in the proportion of detrusor muscle to bladder wall for non-invasive diagnosis of detrusor underactivity in men with lower urinary tract symptoms

To investigate the significance of detrusor muscle thickness (DMT) to bladder wall thickness (BWT) ratio as a detrusor-sarcopenia and a consistently applicable factor for noninvasive diagnosis of detrusor underactivity (DU). We prospectively performed a urodynamic study of 100 male with medical refractory lower-urinary-tract-symptoms during 2017–2019. The DMT, BWT and DMT/BWT ratio were measured by ultrasonography every 50 mL during bladder filling, and were analyzed for non-invasive diagnosis of DU and prediction of prostate surgery outcome with questionnaire and the maximum-flow-rate. Of the 94 patients, DU was urodynamically diagnosed in 24 (25.5%). The DMT/BWT ratio was maintained in all patients until the 50% of the maximum cystometric capacity (MCC), and then rapidly decreased. At 20% of the MCC, the DMT/BWT ratio was significantly lower in the DU group (44.0 ± 4.9% vs. 49.4 ± 6.7%, p = 0.008). The DMT/BWT ratio of less than 47.5% at 20% of the MCC showed the ideal accuracy for diagnosing DU (AUC = 0.763), and was a predictor of failure at 12 months after prostate surgery (OR 8.78, p = 0.024). A DMT/BWT ratio of less than 47.5% at 20% of the MCC is a consistently applicable factor for non-invasive diagnosis of DU and could also be considered detrusor-sarcopenia.

Fourier-transform ion cyclotron resonance mass spectrometry for characterizing proteoforms

Proteoforms contribute functional diversity to the proteome and aberrant proteoforms levels have been implicated in biological dysfunction and disease. Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), with its ultrahigh mass-resolving power, mass accuracy, and versatile tandem MS capabilities, has empowered top-down, middle-down, and native MS-based approaches for characterizing proteoforms and their complexes in biological systems. Herein, we review the features which make FT-ICR MS uniquely suited for measuring proteoform mass with ultrahigh resolution and mass accuracy; obtaining in-depth proteoform sequence coverage with expansive tandem MS capabilities; and unambiguously identifying and localizing post-translational and noncovalent modifications. We highlight examples from our body of work in which we have quantified and comprehensively characterized proteoforms from cardiac and skeletal muscle to better understand conditions such as chronic heart failure, acute myocardial infarction, and sarcopenia. Structural characterization of monoclonal antibodies and their proteoforms by FT-ICR MS and emerging applications, such as native top-down FT-ICR MS and high-throughput top-down FT-ICR MS-based proteomics at 21 T, are also covered. Historically, the information gleaned from FT-ICR MS analyses have helped provide biological insights. We predict FT-ICR MS will continue to enable the study of proteoforms of increasing size from increasingly complex endogenous mixtures and facilitate the benchmarking of sensitive and specific assays for clinical diagnostics. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.

Cellular Senescence in Sarcopenia: Possible Mechanisms and Therapeutic Potential

Aging promotes most degenerative pathologies in mammals, which are characterized by progressive decline of function at molecular, cellular, tissue, and organismal levels and account for a host of health care expenditures in both developing and developed nations. Sarcopenia is a prominent age-related disorder in musculoskeletal system. Defined as gradual and generalized chronic skeletal muscle disorder, sarcopenia involves accelerated loss of muscle mass, strength and function, which is associated with increased adverse functional outcomes and evolutionally refers to muscle wasting accompanied by other geriatric syndromes. More efforts have been made to clarify mechanisms underlying sarcopenia and new findings suggest that it may be feasible to delay age-related sarcopenia by modulating fundamental mechanisms such as cellular senescence. Cellular senescence refers to the essentially irreversible growth arrest mainly regulated by p53/p21^CIP1 and p16^INK4a/pRB pathways as organism ages, possibly detrimentally contributing to sarcopenia via muscle stem cells (MuSCs) dysfunction and the senescence-associated secretory phenotype (SASP) while cellular senescence may have beneficial functions in counteracting cancer progression, tissue regeneration and wound healing. By now diverse studies in mice and humans have established that targeting cellular senescence is a powerful strategy to alleviating sarcopenia. However, the mechanisms through which senescent cells contribute to sarcopenia progression need to be further researched. We review the possible mechanisms involved in muscle stem cells (MuSCs) dysfunction and the SASP resulting from cellular senescence, their associations with sarcopenia, current emerging therapeutic opportunities based on targeting cellular senescence relevant to sarcopenia, and potential paths to developing clinical interventions genetically or pharmacologically.