Sarcopenic obesity: emerging mechanisms and therapeutic potential

Mitochondrial quality control in human health and disease

Mitochondria, the most crucial energy-generating organelles in eukaryotic cells, play a pivotal role in regulating energy metabolism. However, their significance extends beyond this, as they are also indispensable in vital life processes such as cell proliferation, differentiation, immune responses, and redox balance. In response to various physiological signals or external stimuli, a sophisticated mitochondrial quality control (MQC) mechanism has evolved, encompassing key processes like mitochondrial biogenesis, mitochondrial dynamics, and mitophagy, which have garnered increasing attention from researchers to unveil their specific molecular mechanisms. In this review, we present a comprehensive summary of the primary mechanisms and functions of key regulators involved in major components of MQC. Furthermore, the critical physiological functions regulated by MQC and its diverse roles in the progression of various systemic diseases have been described in detail. We also discuss agonists or antagonists targeting MQC, aiming to explore potential therapeutic and research prospects by enhancing MQC to stabilize mitochondrial function.

Sarcopenia Prevalence among Hospitalized Patients with Severe Obesity: An Observational Study

Background: Sarcopenic obesity (SO) is the combination of excess fat, skeletal muscle and muscular strength/function deficit. The ESPEN/EASO have proposed new diagnostic criteria, but the SO prevalence in patients with severe obesity remains to be established. The aim of this study was to establish the SO prevalence in a large cohort of inpatients with obesity, considering sex, age, BMI, type, and number of concomitant diseases. Methods: Patient data of both genders aged between 18 and 90 years with a body mass index (BMI) of ≥30 kg/m2 underwent hospital evaluation including bioelectrical impedance analysis (BIA) and handgrip strength (HS). QoL scores were obtained by the Psychological General Well-Being Index questionnaire. The study was approved by the institutional Ethic Committee. Results: Among the 3858 patients, 444 (11.51%) exhibited a strength deficit, while 3847 (99.71%) had skeletal muscle mass deficit. The prevalence of SO was then 11.48%, with higher rates in women (12.39%), in individuals aged >70 years (27%), and in those reporting a 'poor' QoL (12.6%). No significant difference in SO prevalence was found when stratifying by BMI (30-40 kg/m2 vs. >40 kg/m2, p = 0.1710). In SO patients, osteoarticular diseases (57%), hypertension/heart failure (38%), type 2 diabetes mellitus (34%), and obstructive sleep apnea (32%) were the more frequent comorbidities. Conclusions: The application of ESPEN/EASO-SO criteria in a cohort of inpatients with severe obesity revealed 11.48% SO prevalence, which was associated with age (particularly > 70 years), gender (women), but not BMI, as determinants. Disease staging and QoL screening may improve the identification of SO high-risk patients.

Steatotic Liver Disease: Pathophysiology and Emerging Pharmacotherapies

Steatotic liver disease (SLD) displays a dynamic and complex disease phenotype. Consequently, the metabolic dysfunction-associated steatotic liver disease (MASLD)/metabolic dysfunction-associated steatohepatitis (MASH) therapeutic pipeline is expanding rapidly and in multiple directions. In parallel, noninvasive tools for diagnosing and monitoring responses to therapeutic interventions are being studied, and clinically feasible findings are being explored as primary outcomes in interventional trials. The realization that distinct subgroups exist under the umbrella of SLD should guide more precise and personalized treatment recommendations and facilitate advancements in pharmacotherapeutics. This review summarizes recent updates of pathophysiology-based nomenclature and outlines both effective pharmacotherapeutics and those in the pipeline for MASLD/MASH, detailing their mode of action and the current status of phase 2 and 3 clinical trials. Of the extensive arsenal of pharmacotherapeutics in the MASLD/MASH pipeline, several have been rejected, whereas other, mainly monotherapy options, have shown only marginal benefits and are now being tested as part of combination therapies, yet others are still in development as monotherapies. Although the Food and Drug Administration (FDA) has recently approved resmetirom, additional therapeutic approaches in development will ideally target MASH and fibrosis while improving cardiometabolic risk factors. Due to the urgent need for the development of novel therapeutic strategies and the potential availability of safety and tolerability data, repurposing existing and approved drugs is an appealing option. Finally, it is essential to highlight that SLD and, by extension, MASLD should be recognized and approached as a systemic disease affecting multiple organs, with the vigorous implementation of interdisciplinary and coordinated action plans. SIGNIFICANCE STATEMENT: Steatotic liver disease (SLD), including metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis, is the most prevalent chronic liver condition, affecting more than one-fourth of the global population. This review aims to provide the most recent information regarding SLD pathophysiology, diagnosis, and management according to the latest advancements in the guidelines and clinical trials. Collectively, it is hoped that the information provided furthers the understanding of the current state of SLD with direct clinical implications and stimulates research initiatives.

Sarcopenic obesity in older adults: a clinical overview

Sarcopenic obesity is characterized by a concurrent decline in muscle mass and function, along with increased adipose tissue. Sarcopenic obesity is a growing concern in older adults owing to significant health consequences, including implications for mortality, comorbidities and risk of developing geriatric syndromes. A 2022 consensus statement established a new definition and diagnostic criteria for sarcopenic obesity. The pathophysiology of this condition involves a complex interplay between muscle, adipose tissue, hormonal changes, inflammation, oxidative stress and lifestyle factors, among others. Sarcopenic obesity is treated with a range of management approaches, such as lifestyle interventions, exercise, nutrition and medical therapies. Emerging therapies that were developed for treating other conditions may be relevant to sarcopenic obesity, including novel pharmacological agents and personalized approaches such as precision medicine. In this Review, we synthesize the current knowledge of the clinical importance of sarcopenic obesity, its assessment and diagnosis, along with current and emerging management strategies.

Sex-Specific Effects of Dietary Factors on Sarcopenic Obesity in Korean Elderly: A Nationwide Cross-Sectional Study

This study aimed to compare the dietary factors related to sarcopenia and obesity status in 5458 elderly individuals (2391 men and 3076 women) aged ≥65 years from the Korean National Health and Nutrition Examination Survey (2016-2019). Participants were categorized into normal, sarcopenia, obesity, and sarcopenic obesity groups. Sarcopenic obesity showed a higher prevalence of diabetes and lower HDL cholesterol levels compared to obesity. Sarcopenic obesity exhibited a lower total KHEI score and lower adequacy, including meat/fish/eggs/beans, than normal or obesity. In women, sarcopenic obesity scored lower than obesity on the total KHEI, adequacy for most foods, and balance of energy intake, and lower than sarcopenia on the adequacy of breakfast and milk/milk products. Sarcopenic obesity showed no significant difference in energy intake compared to sarcopenia, and less physical activity compared to sarcopenia and obesity, with a BMI/waist circumference comparable to that of obesity. Low total KHEI scores and scores for meat/fish/eggs/beans were most closely associated with sarcopenia in men and with sarcopenic obesity in women. In conclusion, low dietary quality and inadequate protein-rich foods are possibly associated with the prevalence of sarcopenic obesity in elderly Koreans, especially in women. Adequate energy intake and dietary diversity may be effective in managing sarcopenic obesity.

Effects of low-volume functional and running high-intensity interval training on physical fitness in young adults with overweight/obesity

Objectives: This study examined and compared the effects of functional and running high-intensity interval training (HIIT) on body composition, cardiorespiratory fitness, and muscular fitness of young adults with overweight or obesity. Methods: Forty-five participants (22.1 ± 2.1 years, BMI = 25.2 ± 1.0 kg/m2) were assigned to functional HIIT (HIIT-F; n = 15), running HIIT (HIIT-R; n = 15), or non-training control group (CON; n = 15). Participants in HIIT-F and HIIT-R performed functional exercise based-HIIT (four sets of all-out whole-body exercises including jumping jacks, squats, twist jumps and mountain climbers, et al.) and running HIIT (four sets of running on a treadmill) for 12 weeks, respectively. Body composition, muscular fitness, and cardiorespiratory fitness were assessed pre and post intervention. Results: Both HIIT-F and HIIT-R significantly improved the body composition and cardiorespiratory fitness, with HIIT-F induced greater improvements in lean mass (+1.623 vs. -1.034 kg, p < 0.001), back strength (+6.007 vs. +3.333 kg, p < 0.01), and push-ups (+5.692 vs. 1.923 reps, p < 0.001) than that in HIIT-R. HIIT-R reduced more visceral fat area (VFA) (-11.416 vs. -4.338 cm2, p = 0.052) and induced similar improvement in cardiorespiratory fitness (VO2max, +2.192 vs. +2.885 mL/kg/min, p = 0.792) with HIIT-F. Conclusion: Twelve weeks of HIIT-R or HIIT-F improved physical fitness among young adults with overweight or obesity. Despite the similar impact on cardiorespiratory fitness, HIIT-F generates a better positive effect on muscular fitness relative to HIIT-R, which could be partly explained by the greater increase in lean mass after HIIT-F intervention.

The Safety and Efficacy of Sodium-Glucose Cotransporter-2 Inhibitors for Patients with Sarcopenia or Frailty: Double Edged Sword?

Sodium-glucose cotransporter-2 inhibitors (SGLT-2is) show cardiovascular protective effects, regardless of the patient's history of diabetes mellitus (DM). SGLT2is suppressed cardiovascular adverse events in patients with type 2 DM, and furthermore, SGLT-2is reduced the risk of worsening heart failure (HF) events or cardiovascular death in patients with HF. Along with these research findings, SGLT-2is are recommended for patients with HF in the latest guidelines. Despite these benefits, the concern surrounding the increasing risk of body weight loss and other adverse events has not yet been resolved, especially for patients with sarcopenia or frailty. The DAPA-HF and DELIVER trials consistently showed the efficacy and safety of SGLT-2i for HF patients with frailty. However, the Rockwood frailty index that derived from a cumulative deficit model was employed for frailty assessment in these trials, which might not be suitable for the evaluation of physical frailty or sarcopenia alone. There is no fixed consensus on which evaluation tool to use or its cutoff value for the diagnosis and assessment of frailty in HF patients, or which patients can receive SGLT-2i safely. In this review, we summarize the methodology of frailty assessment and discuss the efficacy and safety of SGLT-2i for HF patients with sarcopenia or frailty.

Effects of Fermented Polygonum cuspidatum on the Skeletal Muscle Functions

Plant extract fermentation is widely employed to enhance the nutritional and pharmaceutical value of functional foods. Polygonum cuspidatum (Pc) contains flavonoids, anthraquinones, and stilbenes, imparting protective effects against inflammatory diseases, cancer, diabetes, and cardiovascular diseases. However, the effects of fermented Pc on skeletal muscle strength remain unexplored. In this study, we generated fermented Pc using a complex of microorganisms containing Lactobacillus spp. (McPc) and assessed its effects on muscle strength and motor function in mice. Compared to unfermented Pc water extract, elevated levels of emodin and resveratrol were noted in McPc. This was identified and quantified using UPLC-QTOF/MS and HPLC techniques. Gene expression profiling through RNA-seq and quantitative RT-PCR revealed that McPc administration upregulated the expression of genes associated with antioxidants, glycolysis, oxidative phosphorylation, fatty acid oxidation, and mitochondrial biogenesis in cultured C2C12 myotubes and the gastrocnemius muscle in mice. McPc significantly improved skeletal muscle strength, motor coordination, and traction force in mice subjected to sciatic neurectomy and high-fat diet (HFD). McPc administration exhibited more pronounced improvement of obesity, hyperglycemia, fatty liver, and hyperlipidemia in HFD mice compared to control group. These findings support the notion that emodin and resveratrol-enriched McPc may offer health benefits for addressing skeletal muscle weakness.

Clinical impact of sarcopenia for overweight or obese patients with colorectal cancer

BACKGROUND

Sarcopenia, overweight and obesity are all dynamic changes in body composition, which may have a negative effect on the prognosis for patients with colorectal cancer. The aim of this study was to investigate the predictive role of sarcopenia on overweight or obese patients with colorectal cancer.

METHODS

We conducted an observative study on the population of overweight or obese patients with colorectal cancer who underwent curative surgeries in two centers between 2015 and 2021. They were grouped by the presence of sarcopenia. Propensity score match analysis was used to balance the baseline of clinicopathologic characteristics of the two groups. Then, the postoperative outcomes between the two groups were compared. Independent risk factors were evaluated for complications using univariate and multivariate analysis.

RESULTS

Of 827 patients enrolled, 126 patients were matched for analysis. Patients with sarcopenia had a higher incidence of total complication and medical complications, a higher rate of laparoscopic surgery performed and higher hospitalization costs. Old age (≥65 years, P = 0.012), ASA grade (III, P = 0.008) and sarcopenia (P = 0.036) were independent risk factors for total complications. ASA grade (III, P = 0.002) and sarcopenia (P = 0.017) were independent risk factors for medical complications.

CONCLUSIONS

Sarcopenia was prevalent among overweight or obese patients with colorectal cancer and was associated with negative postoperative outcomes. Early recognition of changes in body composition could help surgeons be well prepared for surgical treatment for overweight or obese patients.

Lean mass and associated factors in women with PCOS with different phenotypes

Although current evidence suggests increased risk of obesity, insulin resistance, and metabolic alterations in patients with polycystic ovary syndrome (PCOS), especially of a hyperandrogenic phenotype, the impact of each one of these variables on muscle mass remains uncertain. In this case-control study, we evaluated clinical and hormonal characteristics related to lean body mass according to the different PCOS phenotypes. We performed clinical, metabolic, and hormonal assessments and evaluated body compartments by dual-energy X-ray absorptiometry in 133 women of reproductive age. Creatinine served as an indirect marker of lean mass. Median age was 28 (range, 17-37) years. Women with phenotypes A and B (n = 59) had higher body mass index (BMI) and metabolic syndrome prevalence than those with phenotype C (n = 23) and controls (n = 51) (p<0.005). Women with phenotypes A and B also had higher Ferriman-Gallwey score (p<0.001), insulin levels (p = 0.006), HOMA-IR (p = 0.008), testosterone (p = 0.008), free androgen index (FAI) (p<0.001), fat mass index (FMI) (p = 0.015), android-to-gynoid fat ratio (p = 0.036), and bone mineral density (BMD) at lumbar spine (p = 0.027) and total femur (p = 0.013) than controls. Median appendicular lean mass index (ALMI) was higher in phenotypes A and B than in controls (7.01 [IQR, 6.33-8.02] vs. 6.69 [IQR, 5.94-7.09], p = 0.024), but it did not differ significantly from that in phenotype C (6.60 [IQR, 6.16-7.22], p = 0.222). Even after adjusting for BMI, ALMI correlated positively with creatinine in women with phenotypes A and B (rho = 0.319, p = 0.023) but not in those with phenotype C (p = 0.238) or controls (p = 0.097). In multivariate linear regression analyses, ALMI was positively associated with insulin, FAI, FMI, and total femur BMD. The present results suggest that fasting insulin, FAI, fat mass, and total femur BMD were positively associated with increased lean mass in women with PCOS phenotypes A and B.

Prognostic significance of nutritional indices in patients with head and neck squamous cell carcinoma treated with immune checkpoint inhibitors

BACKGROUND

Although patients with head and neck squamous cell cancer (HNSCC) often show malnutrition, its effects on immune checkpoint inhibitor (ICI) treatment outcomes in these patients are unclear.

OBJECTIVES

To investigate the prognostic influence of nutritional indices in patients with HNSCC treated with ICIs and determine the optimal indices.

METHODS

This retrospective study included 106 patients with HNSCC treated with ICIs between 2017 and 2022. The prognostic influences of body mass index (BMI), geriatric nutritional risk index (GNRI), and prognostic nutritional index (PNI) on overall survival (OS) and progression-free survival (PFS) were analysed using the Kaplan-Meier method and Cox-regression models.

RESULTS

The 1-year PFS rates in the groups with high and low BMI, GNRI, and PNI were, respectively, 24.2% and 28.4% (p = .731), 29.7% and 14.4% (p = .024), and 30.3% and 13.9% (p = .015). PNI was an independent prognostic factor for both PFS (hazard ratio (HR) = 1.89; 95% confidence interval (CI), 1.08-3.29) and OS (HR = 3.26; 95% CI, 1.66-6.40).

CONCLUSIONS

PNI can predict ICI outcomes and should be assessed when ICI treatment is considered.

Sarcopenia, sarcopenic obesity and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), sarcopenia and sarcopenic obesity (SO) are highly prevalent conditions that may coexist, especially in the aging population, without any approved pharmacologic treatment for all of them. There are multiple pathophysiologic mechanisms suggested to explain an association between NAFLD and sarcopenia or SO, including alterations in the adipokines, cytokines, hepatokines and myokines, which may interplay with other factors, such as aging, diet and physical inactivity. In clinical terms, most observational studies support an association between NAFLD and sarcopenia or SO; importantly, there are few cohort studies indicating higher mortality in patients with NAFLD and sarcopenia. Their association also bears some treatment considerations: for example, pioglitazone or vitamin E, suggested as off label treatment for selected patients with nonalcoholic steatohepatitis, may be recommended in the coexistence of sarcopenia or SO, since limited evidence did not show adverse effects of them on sarcopenia and abdominal obesity. In this review, evidence linking sarcopenia and SO with NAFLD is summarized, with a special focus on clinical data. A synopsis of the major pathophysiological links between NAFLD and sarcopenia/SO is initially presented, followed by selected clinical studies and, finally, treatment considerations in patients with NAFLD and sarcopenia or SO are discussed.