Repurposing Drugs for Diabetes Mellitus as Potential Pharmacological Treatments for Sarcopenia - A Narrative Review

Nutrition of aging people with diabetes mellitus: Focus on sarcopenia

As populations age, chronic diseases accumulate, and new health conditions emerge. One noteworthy pair that warrants further evaluation is diabetes mellitus and sarcopenia, given that the latter occurs in 28 % of the population aged over 50 who have diabetes mellitus. The management of both entails nutritional interventions, making the development of unified dietary recommendations an alluring strategy. This review aims to elucidate the current recommendations for the combined management of sarcopenia and diabetes, while featuring elements that require further research. The goal of nutritional management is to improve muscle mass and strength while regulating metabolic risk and glucose levels. To ensure muscle synthesis in the elderly, recommendations align at daily calorie intake that exceeds 30 kcal/kg, with adjustments based on comorbidities. Additionally, a protein intake of at least 1-1.2 g/kg/d is essential, emphasizing both daily and per-meal intake, and can be achieved through diet or branched-amino-acids supplements. Specific considerations for diabetes include restricted protein intake in diabetic nephropathy and exploring the potential link between branched amino acids and insulin resistance. Further recommendations that both promote metabolic health and have demonstrated at least a potential to increase muscle strength include prioritizing polyunsaturated fatty acids as a fat source and maintaining adequate levels of vitamin D. Clinicians should consult their patients on dietary optimization, but evidence is insufficient to recommend additional supplementation. Lastly, an emerging challenge of diabetes and sarcopenia is sarcopenic obesity, which requires the combination of a hypocaloric diet with increased protein intake.

Emerging Therapeutic Strategies in Sarcopenia: An Updated Review on Pathogenesis and Treatment Advances

Sarcopenia is a prevalent degenerative skeletal muscle condition in the elderly population, posing a tremendous burden on diseased individuals and healthcare systems worldwide. Conventionally, sarcopenia is currently managed through nutritional interventions, physical therapy, and lifestyle modification, with no pharmaceutical agents being approved for specific use in this disease. As the pathogenesis of sarcopenia is still poorly understood and there is no treatment recognized as universally effective, recent research efforts have been directed at better comprehending this illness and diversifying treatment strategies. In this respect, this paper overviews the new advances in sarcopenia treatment in correlation with its underlying mechanisms. Specifically, this review creates an updated framework for sarcopenia, describing its etiology, pathogenesis, risk factors, and conventional treatments, further discussing emerging therapeutic approaches like new drug formulations, drug delivery systems, stem cell therapies, and tissue-engineered scaffolds in more detail.

The Current Landscape of Pharmacotherapies for Sarcopenia

Sarcopenia is a skeletal muscle disorder characterized by progressive and generalized decline in muscle mass and function. Although it is mostly known as an age-related disorder, it can also occur secondary to systemic diseases such as malignancy or organ failure. It has demonstrated a significant relationship with adverse outcomes, e.g., falls, disabilities, and even mortality. Several breakthroughs have been made to find a pharmaceutical therapy for sarcopenia over the years, and some have come up with promising findings. Yet still no drug has been approved for its treatment. The key factor that makes finding an effective pharmacotherapy so challenging is the general paradigm of standalone/single diseases, traditionally adopted in medicine. Today, it is well known that sarcopenia is a complex disorder caused by multiple factors, e.g., imbalance in protein turnover, satellite cell and mitochondrial dysfunction, hormonal changes, low-grade inflammation, senescence, anorexia of aging, and behavioral factors such as low physical activity. Therefore, pharmaceuticals, either alone or combined, that exhibit multiple actions on these factors simultaneously will likely be the drug of choice to manage sarcopenia. Among various drug options explored throughout the years, testosterone still has the most cumulated evidence regarding its effects on muscle health and its safety. A mas receptor agonist, BIO101, stands out as a recent promising pharmaceutical. In addition to the conventional strategies (i.e., nutritional support and physical exercise), therapeutics with multiple targets of action or combination of multiple therapeutics with different targets/modes of action appear to promise greater benefit for the prevention and treatment of sarcopenia.

Drug-related sarcopenia as a secondary sarcopenia

Sarcopenia has a significant impact on falls, physical function, activities of daily living, and quality of life in older adults, and its prevention and treatment are becoming increasingly important as the global population ages. In addition to primary age-related sarcopenia, activity-related sarcopenia, disease-related sarcopenia, and nutrition-related sarcopenia have been proposed as secondary sarcopenia. Polypharmacy and potentially inappropriate medication based on multiple diseases cause health problems in older patients. In some cases, drugs used for therapeutic or preventive purposes act on skeletal muscle as adverse drug reactions and induce sarcopenia. Although sarcopenia caused by these adverse drug reactions may be more common in older patients, in particular those taking many medications, drug-related sarcopenia has not yet received much attention. This review summarizes drugs that may induce sarcopenia and emphasizes the importance of drug-related sarcopenia as a secondary sarcopenia. Geriatr Gerontol Int 2024; 24: 195-203.

Diabetes Pharmacotherapy and its effects on the Skeletal Muscle Energy Metabolism

The disorders of skeletal muscle metabolism in patients with Type 2 diabetes mellitus (T2DM), such as mitochondrial defection and glucose transporters (GLUTs) translocation dysfunctions, are not uncommon. Therefore, when anti-diabetic drugs were used in various chronic diseases associated with hyperglycemia, the impact on skeletal muscle should not be ignored. However, current studies mainly focus on muscle mass rather than metabolism or functions. Anti-diabetic drugs might have a harmful or beneficial impact on skeletal muscle. In this review, we summarize the upto- date studies on the effects of anti-diabetic drugs and some natural compounds on skeletal muscle metabolism, focusing primarily on emerging data from pre-clinical to clinical studies. Given the extensive use of anti-diabetic drugs and the common sarcopenia, a better understanding of energy metabolism in skeletal muscle deserves attention in future studies.

Sarcopenia and Diabetes: A Detrimental Liaison of Advancing Age

Sarcopenia is an age-related clinical complaint characterized by the progressive deterioration of skeletal muscle mass and strength over time. Type 2 diabetes (T2D) is associated with faster and more relevant skeletal muscle impairment. Both conditions influence each other, leading to negative consequences on glycemic control, cardiovascular risk, general health status, risk of falls, frailty, overall quality of life, and mortality. PubMed/Medline, Scopus, Web of Science, and Google Scholar were searched for research articles, scientific reports, observational studies, clinical trials, narrative and systematic reviews, and meta-analyses to review the evidence on the pathophysiology of di-abetes-induced sarcopenia, its relevance in terms of glucose control and diabetes-related outcomes, and diagnostic and therapeutic challenges. The review comprehensively addresses key elements for the clinical definition and diagnostic criteria of sarcopenia, the pathophysiological correlation be-tween T2D, sarcopenia, and related outcomes, a critical review of the role of antihyperglycemic treatment on skeletal muscle health, and perspectives on the role of specific treatment targeting myokine signaling pathways involved in glucose control and the regulation of skeletal muscle metabolism and trophism. Prompt diagnosis and adequate management, including lifestyle inter-vention, health diet programs, micronutrient supplementation, physical exercise, and pharmaco-logical treatment, are needed to prevent or delay skeletal muscle deterioration in T2D.

Sodium-glucose co-transporter 2 inhibitors and Sarcopenia: A controversy that must be solved

Diabetes mellitus is a risk factor for muscle loss and sarcopenia. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) or "gliflozins" are one of the newest anti-hyperglycemic drugs. They reduce blood glucose levels by inhibiting renal glucose reabsorption in the early proximal convoluted tubule. Various randomized trials showed that SGLT2i have cardio-protective and reno-protective action. SGLT2i also affect body composition. They usually decrease body fat percentage, visceral and subcutaneous adipose tissue. However, regarding the muscle mass, there are conflicting findings some studies showing detrimental effects and others showed neutral or beneficial effects. This issue is extremely important not only because of the wide use of SGLT2i around globe; but also skeletal muscle mass consumes large amounts of calories during exercise and is an important determinant of resting metabolic rate and skeletal muscle loss hinders energy consumption leading to obesity. In this systematic review, we extensively reviewed the experimental and clinical studies regarding the impact of SGLT2i on muscle mass and related metabolic alterations. Importantly, studies are heterogeneous and there is unmet need to highlight the alterations in muscle during SGLT2i use.

Pathophysiology of sarcopenia: Genetic factors and their interplay with environmental factors

Sarcopenia is a geriatric disorder characterized by a progressive decline in muscle mass and function. This disorder has been associated with a range of adverse health outcomes, including fractures, functional deterioration, and increased mortality. The pathophysiology of sarcopenia is highly complex and multifactorial, involving both genetic and environmental factors as key contributors. This review consolidates current knowledge on the genetic factors influencing the pathogenesis of sarcopenia, particularly focusing on the altered gene expression of structural and metabolic proteins, growth factors, hormones, and inflammatory cytokines. While the influence of environmental factors such as physical inactivity, chronic diseases, smoking, alcohol consumption, and sleep disturbances on sarcopenia is relatively well understood, there is a dearth of studies examining their mechanistic roles. Therefore, this review emphasizes the interplay between genetic and environmental factors, elucidating their cumulative role in exacerbating the progression of sarcopenia beyond their individual effects. The unique contribution of this review lies in synthesizing the latest evidence on the genetic factors and their interaction with environmental factors, aiming to inform the development of novel therapeutic or preventive interventions for sarcopenia.