Sarcopenia associates with SNAP-25 SNPs and a miRNAs profile which is modulated by structured rehabilitation treatment

MiR-495 reverses in the mechanical unloading, random rotating and aging induced muscle atrophy via targeting MyoD and inactivating the Myostatin/TGF-β/Smad3 axis

Mechanical unloading can lead to homeostasis imbalance and severe muscle disease, in which muscle atrophy was one of the disused diseases. However, there were limited therapeutic targets for such diseases. In this study, miR-495 was found dramatically reduced in atrophic skeletal muscle induced by mechanical unloading models both in vitro and in vivo, including the random positioning model (RPM), tail-suspension (TS) model, and aged mice model. Enforced miR-495 expression by its mimic could enormously facilitate the differentiation and regeneration of both mouse myoblast C2C12 cells and muscle satellite cells. Furthermore, MyoD was proved as the directly interacted gene of miR-495, and their interaction was crucial for myotube formation. Enforced miR-495 expression could intensively strengthen the muscle mass, in situ muscular electrophysiological indexes, including peak tetanic tension (Po) and peak twitch tension (Pt), and the cross-sectional areas (CSA) of muscle fibers via targeting MyoD and inactivating the Myostatin/TGF-β/Smad3 signaling pathway, indicating that miR-495 can be proposed as an effective target for muscle atrophy treatment induced by in the mechanical unloading, random rotating and aging.

Sarcopenia and the biological determinants of aging: A narrative review from a geroscience perspective

BACKGROUND

The physiopathology of sarcopenia shares common biological cascades with the aging process, as does any other age-related condition. However, our understanding of the interconnected pathways between diagnosed sarcopenia and aging remains limited, lacking sufficient scientific evidence.

METHODS

This narrative review aims to gather and describe the current evidence on the relationship between biological aging determinants, commonly referred to as the hallmarks of aging, and diagnosed sarcopenia in humans.

RESULTS

Among the twelve hallmarks of aging studied, there appears to be a substantial association between sarcopenia and mitochondrial dysfunction, epigenetic alterations, deregulated nutrient sensing, and altered intercellular communication. Although limited, preliminary evidence suggests a promising association between sarcopenia and genomic instability or stem cell exhaustion.

DISCUSSION

Overall, an imbalance in energy regulation, characterized by impaired mitochondrial energy production and alterations in circulatory markers, is commonly associated with sarcopenia and may reflect the interplay between aging physiology and sarcopenia biology.

Impact of ageing and disuse on neuromuscular junction and mitochondrial function and morphology: Current evidence and controversies

Inactivity and ageing can have a detrimental impact on skeletal muscle and the neuromuscular junction (NMJ). Decreased physical activity results in muscle atrophy, impaired mitochondrial function, and NMJ instability. Ageing is associated with a progressive decrease in muscle mass, deterioration of mitochondrial function in the motor axon terminals and in myofibres, NMJ instability and loss of motor units. Focusing on the impact of inactivity and ageing, this review examines the consequences on NMJ stability and the role of mitochondrial dysfunction, delving into their complex relationship with ageing and disuse. Evidence suggests that mitochondrial dysfunction can be a pathogenic driver for NMJ alterations, with studies revealing the role of mitochondrial defects in motor neuron degeneration and NMJ instability. Two perspectives behind NMJ instability are discussed: one is that mitochondrial dysfunction in skeletal muscle triggers NMJ deterioration, the other envisages dysfunction of motor terminal mitochondria as a primary contributor to NMJ instability. While evidence from these studies supports both perspectives on the relationship between NMJ dysfunction and mitochondrial impairment, gaps persist in the understanding of how mitochondrial dysfunction can cause NMJ deterioration. Further research, both in humans and in animal models, is essential for unravelling the mechanisms and potential interventions for age- and inactivity-related neuromuscular and mitochondrial alterations.

Age-Related sncRNAs in Human Hippocampal Tissue Samples: Focusing on Deregulated miRNAs

Small non-coding RNAs (sncRNAs), particularly microRNAs (miRNAs), play an important role in transcriptome regulation by binding to mRNAs and post-transcriptionally inhibiting protein production. This regulation occurs in both physiological and pathological conditions, where the expression of many miRNAs is altered. Previous reports by our group and others have demonstrated that miRNA expression is also altered during aging. However, most studies have analyzed human peripheral blood samples or brain samples from animal models, leaving a gap in knowledge regarding miRNA expression in the human brain. In this work, we analyzed the expression of sncRNAs from coronal sections of human hippocampal samples, a tissue with a high vulnerability to deleterious conditions such as aging. Samples from young (n = 5, 27-49 years old), old (n = 8, 58-88 years old), and centenarian (n = 3, 97, 99, and 100 years old) individuals were included. Our results reveal that sncRNAs, particularly miRNAs, are differentially expressed (DE) in the human hippocampus with aging. Besides, miRNA-mediated regulatory networks revealed significant interactions with mRNAs deregulated in the same hippocampal samples. Surprisingly, 80% of DE mRNA in the centenarian vs. old comparison are regulated by hsa-miR-192-5p and hsa-miR-3135b. Additionally, validated hsa-miR-6826-5p, hsa-let-7b-3p, hsa-miR-7846, and hsa-miR-451a emerged as promising miRNAs that are deregulated with aging and should be further investigated.

MicroRNAs as commonly expressed biomarkers for sarcopenia and frailty: A systematic review

BACKGROUND

Coexistent sarcopenia and frailty is more strongly associated with adverse health outcomes than each condition alone. As the importance of coexistent sarcopenia and frailty increases, exploring their underlying mechanisms is warranted. Recently, noncoding ribonucleic acids (RNAs) have been suggested as potential biomarkers of sarcopenia and frailty. This systematic review aimed to summarize noncoding RNAs commonly expressed in sarcopenia and frailty, and to search the predicted target genes and biological pathways of them.

METHODS

We systematically searched the literatures on PubMed, Embase, Cochrane Library, Web of Science, and Scopus for literature published till November 15, 2023. A total of 7,202 literatures were initially retrieved. After de-duplication, 34 studies (26 sarcopenia-related and 8 frailty-related) were full-text reviewed, and 15 studies (11 sarcopenia-related and 4 frailty-related) were finally included.

RESULTS

miR-29a-3p, miR-29b-3p, and miR-328 were identified as commonly expressed in same direction in sarcopenia and frailty. These microRNAs (miRNAs), identified in the literature search using PubMed, modulate transforming growth factor-β signaling via extracellular matrix components and calcineurin/nuclear factor of activated T cells 3 signaling via sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a, which are involved in regulating skeletal muscle fibrosis and the growth of slow-twitch muscle fibers, respectively. miR-155-5p, miR-486, and miR-23a-3p were also commonly expressed in two conditions, although in different or conflicting directions.

CONCLUSION

In this systematic review, we highlight the potential of shared miRNAs that exhibit consistent expression patterns as biomarkers for the early diagnosis and progression assessment of both sarcopenia and frailty.

Non-coding RNAs in exercise immunology: A systematic review

Regular physical exercise has been recognized as a potent modulator of immune function, with its effects including enhanced immune surveillance, reduced inflammation, and improved overall health. While strong evidence exists that physical exercise affects the specific expression and activity of non-coding RNAs (ncRNAs) also involved in immune system regulation, heterogeneity in individual study designs and analyzed exercise protocols exists, and a condensed list of functional, exercise-dependent ncRNAs with known targets in the immune system is missing from the literature. A systematic review and qualitative analysis was used to identify and categorize ncRNAs participating in immune modulation by physical exercise. Two combined approaches were used: (a) a systematic literature search for "ncRNA and exercise immunology", (b) and a database search for microRNAs (miRNAs) (miRTarBase and DIANA-Tarbase v8) aligned with known target genes in the immune system based on the Reactome database, combined with a systematic literature search for "ncRNA and exercise". Literature searches were based on PubMed, Web of Science, and SPORTDiscus; and miRNA databases were filtered for targets validated by in vitro experimental data. Studies were eligible if they reported on exercise-based interventions in healthy humans. After duplicate removal, 95 studies were included reporting on 164 miRNAs, which were used for the qualitative synthesis. Six studies reporting on long-noncoding RNAs (lncRNAs) or circular RNAs were also identified. Results were analyzed using ordering tables that included exercise modality (endurance/resistance exercise), acute or chronic interventions, as well as the consistency in reported change between studies. Evaluation criteria were defined as "validated" with 100% of ≥3 independent studies showing identical direction of regulation, "plausible" (≥80%), or "suggestive" (≥70%). For resistance exercise, upregulation of miR-206 was validated while downregulation of miR-133a appeared plausible. For endurance exercise, 15 miRNAs were categorized as validated, with 12 miRNAs being consistently elevated and 3 miRNAs being downregulated, most of them after acute exercise training. In conclusion, our approach provides evidence that miRNAs play a major role in exercise-induced effects on the innate and adaptive immune system by targeting different pathways affecting immune cell distribution, function, and trafficking as well as production of (anti-)inflammatory cytokines. miRNAs miR-15, miR-29c, miR-30a, miR-142/3, miR-181a, and miR-338 emerged as key players in mediating the immunomodulatory effects of exercise predominantly after acute bouts of endurance exercise.

Sarcopenia as a Risk Factor for Alzheimer's Disease: Genetic and Epigenetic Perspectives

Sarcopenia, defined as the age-associated loss of muscle mass and increased fragility with age, is increasing worldwide. The condition often precedes the development of Alzheimer's disease, thereby decreasing the levels of mobility and physical activity in those affected. Indeed, the loss of muscle mass has, in some studies, been associated with an increased risk of Alzheimer's disease and other dementias. However, a detailed understanding of the interplay between both conditions is not available and needs to be thoroughly addressed. In the following review, we focus on several genes, specifically APOE, BDNF, ACE, FTO, and FNDC5, that have been associated with both conditions. We also discuss the epigenetic regulation of each of these genes along with non-coding RNAs (ncRNAs) that may have a role in the development of both the sarcopenic and Alzheimer's disease phenotypes. Finally, we assert that the application of systems biology will unravel the relationship between sarcopenia and Alzheimer's disease and believe that the prevention of muscle loss in older age will reduce the incidence of debilitating cognitive decline.

Restoration of epigenetic impairment in the skeletal muscle and chronic inflammation resolution as a therapeutic approach in sarcopenia

Sarcopenia is an age-associated loss of skeletal muscle mass, strength, and function, accompanied by severe adverse health outcomes, such as falls and fractures, functional decline, high health costs, and mortality. Hence, its prevention and treatment have become increasingly urgent. However, despite the wide prevalence and extensive research on sarcopenia, no FDA-approved disease-modifying drugs exist. This is probably due to a poor understanding of the mechanisms underlying its pathophysiology. Recent evidence demonstrate that sarcopenia development is characterized by two key elements: (i) epigenetic dysregulation of multiple molecular pathways associated with sarcopenia pathogenesis, such as protein remodeling, insulin resistance, mitochondria impairments, and (ii) the creation of a systemic, chronic, low-grade inflammation (SCLGI). In this review, we focus on the epigenetic regulators that have been implicated in skeletal muscle deterioration, their individual roles, and possible crosstalk. We also discuss epidrugs, which are the pharmaceuticals with the potential to restore the epigenetic mechanisms deregulated in sarcopenia. In addition, we discuss the mechanisms underlying failed SCLGI resolution in sarcopenia and the potential application of pro-resolving molecules, comprising specialized pro-resolving mediators (SPMs) and their stable mimetics and receptor agonists. These compounds, as well as epidrugs, reveal beneficial effects in preclinical studies related to sarcopenia. Based on these encouraging observations, we propose the combination of epidrugs with SCLI-resolving agents as a new therapeutic approach for sarcopenia that can effectively attenuate of its manifestations.

Plasma microRNA signature associated with skeletal muscle wasting in post-menopausal osteoporotic women

BACKGROUND

Skeletal muscle mass wasting almost invariably accompanies bone loss in elderly, and the coexistence of these two conditions depends on the tight endocrine crosstalk existing between the two organs, other than the biomechanical coupling. Since the current diagnostics limitation in this field, and given the progressive population aging, more effective tools are needed. The aim of this study was to identify circulating microRNAs (miRNAs) as potential biomarkers for muscle mass wasting in post-menopausal osteoporotic women.

METHODS

One hundred seventy-nine miRNAs were assayed by quantitative real-time polymerase chain reaction in plasma samples from 28 otherwise healthy post-menopausal osteoporotic women (73.4 ± 6.6 years old). The cohort was divided in tertiles based on appendicular skeletal muscle mass index (ASMMI) to better highlight the differences on skeletal muscle mass (first tertile: n = 9, ASMMI = 4.88 ± 0.40 kg·m-2; second tertile: n = 10, ASMMI = 5.73 ± 0.23 kg·m-2; third tertile: n = 9, ASMMI = 6.40 ± 0.22 kg·m-2). Receiver operating characteristic (ROC) curves were calculated to estimate the diagnostic potential of miRNAs. miRNAs displaying a statistically significant fold change ≥ ±1.5 and area under the curve (AUC) > 0.800 (P < 0.05) between the first and third tertiles were considered. A linear regression model was applied to estimate the association between miRNA expression and ASMMI in the whole population, adjusting for body mass index, age, total fat (measured by total-body dual-energy X-ray absorptiometry [DXA]) and bone mineral density (measured by femur DXA). Circulating levels of adipo-myokines were evaluated by bead-based immunofluorescent assays and enzyme-linked immunosorbent assays.

RESULTS

Five miRNAs (hsa-miR-221-3p, hsa-miR-374b-5p, hsa-miR-146a-5p, hsa-miR-126-5p and hsa-miR-425-5p) resulted down-regulated and two miRNAs (hsa-miR-145-5p and hsa-miR-25-3p) were up-regulated in the first tertile (relative-low ASMMI) compared with the third tertile (relative-high ASMMI) (fold change ≥ ±1.5; P-value < 0.05). All the corresponding ROC curves had AUC > 0.8 (P < 0.05). Two signatures hsa-miR-126-5p, hsa-miR-146a-5p and hsa-miR-425-5p; and hsa-miR-126-5p, hsa-miR-146a-5p, hsa-miR-145-5p and hsa-miR-25-3p showed the highest AUC, 0.914 (sensitivity = 77.78%; specificity = 100.00%) and 0.901 (sensitivity = 88.89%; specificity = 100.00%), respectively.

CONCLUSIONS

In this study, we identified, for the first time, two miRNA signatures, hsa-miR-126-5p, hsa-miR-146a-5p and hsa-miR-425-5p; and hsa-miR-126-5p, hsa-miR-146a-5p, hsa-miR-145-5p and hsa-miR-25-3p, specifically associated with muscle mass wasting in post-menopausal osteoporotic women.

The epigenetics of frailty

The conceptual change of frailty, from a physical to a biopsychosocial phenotype, expanded the field of frailty, including social and behavioral domains with critical interaction between different frailty models. Environmental exposures - including physical exercise, psychosocial factors and diet - may play a role in the frailty pathophysiology. Complex underlying mechanisms involve the progressive interactions of genetics with epigenetics and of multimorbidity with environmental factors. Here we review the literature on possible mechanisms explaining the association between epigenetic hallmarks (i.e., global DNA methylation, DNA methylation age acceleration and microRNAs) and frailty, considered as biomarkers of aging. Frailty could be considered the result of environmental epigenetic factors on biological aging, caused by conflicting DNA methylation age and chronological age.

Thyroarytenoid Oxidative Metabolism and Synaptic Signaling Dysregulation in the Female Pink1-/- Rat

OBJECTIVES AND HYPOTHESIS

Vocal dysfunction, including hypophonia, in Parkinson disease (PD) manifests in the prodromal period and significantly impacts an individual's quality of life. Data from human studies suggest that pathology leading to vocal deficits may be structurally related to the larynx and its function. The Pink1-/- rat is a translational model used to study pathogenesis in the context of early-stage mitochondrial dysfunction. The primary objective of this work was to identify differentially expressed genes in the thyroarytenoid muscle and examine the dysregulated biological pathways in the female rat.

METHODS

RNA sequencing was used to determine thyroarytenoid (TA) muscle gene expression in adult female Pink1-/- rats compared with controls. A bioinformatic approach and the ENRICHR gene analysis tool were used to compare the sequencing dataset with biological pathways and processes, disease relationships, and drug-repurposing compounds. Weighted Gene Co-expression Network Analysis was used to construct biological network modules. The data were compared with a previously published dataset in male rats.

RESULTS

Significant upregulated pathways in female Pink1-/- rats included fatty acid oxidation and muscle contraction, synaptic transmission, and neuromuscular processes. Downregulated pathways included anterograde transsynaptic signaling, chemical synaptic transmission, and ion release. Several drug treatment options including cetuximab, fluoxetine, and resveratrol are hypothesized to reverse observed genetic dysregulation.

CONCLUSIONS

Data presented here are useful for identifying biological pathways that may underlie the mechanisms of peripheral dysfunction including neuromuscular synaptic transmission to the TA muscle. These experimental biomarkers have the potential to be targeted as sites for improving the treatment for hypophonia in early-stage PD.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:3412-3421, 2023.

The Role of SNAP-25 in Autism Spectrum Disorders Onset Patterns

Autism spectrum disorders (ASD) can present with different onset and timing of symptom development; children may manifest symptoms early in their first year of life, i.e., early onset (EO-ASD), or may lose already achieved skills during their second year of life, thus showing a regressive-type onset (RO-ASD). It is still controversial whether regression represents a neurobiological subtype of ASD, resulting from distinct genetic and environmental causes. We focused this study on the 25 kD synaptosomal-associated protein (SNAP-25) gene involved in both post-synaptic formation and adhesion and considered a key player in the pathogenesis of ASD. To this end, four single nucleotide polymorphisms (SNPs) of the SNAP-25 gene, rs363050, rs363039, rs363043, and rs1051312, already known to be involved in neurodevelopmental and psychiatric disorders, were analyzed in a cohort of 69 children with EO-ASD and 58 children with RO-ASD. Both the rs363039 G allele and GG genotype were significantly more frequently carried by patients with EO-ASD than those with RO-ASD and healthy controls (HC). On the contrary, the rs1051312 T allele and TT genotype were more frequent in individuals with RO-ASD than those with EO-ASD and HC. Thus, two different SNAP-25 alleles/genotypes seem to discriminate between EO-ASD and RO-ASD. Notably, rs1051312 is located in the 3' untranslated region (UTR) of the gene and is the target of microRNA (miRNA) regulation, suggesting a possible epigenetic role in the onset of regressive autism. These SNPs, by discriminating two different onset patterns, may represent diagnostic biomarkers of ASD and may provide insight into the different biological mechanisms towards the development of better tailored therapeutic and rehabilitative approaches.

Sarcopenia and noncoding RNAs: A comprehensive review

Sarcopenia is an elderly disease and is related to frailty and loss of muscle mass (atrophy) of older adults. The exact molecular mechanisms contributing to the pathogenesis of disease are yet to be discovered. In recent years, the role of noncoding RNAs in the pathogenesis of almost every kind of malignant and nonmalignant conditions is pinpointed. Regarding their regulatory function, there have been an increased number of studies on the role of noncoding RNAs in the progress of sarcopenia. In this manuscript, we review the role of microRNAs and long noncoding RNAs in development and progression of disease. We also discuss their potential as therapeutic targets in this condition.

Evaluation of serum miRNAs expression in frail and robust subjects undergoing multicomponent exercise protocol (VIVIFRAIL)

BACKGROUND

Frailty, defined as physical performance impairment, is a common condition in older adults and can anticipate the development of sarcopenia, a geriatric syndrome characterized by loss of muscle strength and mass. microRNAs (miRNAs) are short molecules of RNA endowed with the ability to modulate gene expression; miRNAs are present in serum and are considered potential biomarkers for several diseases. Serum concentration of miR-451a, miR-93-5p, miR-155-5p, miR-421-3p, miR-425-5p, miR-495-3p and miR-744-5p was recently shown to be altered in sarcopenic patients.

METHODS

We verified if a particular miRNAs pattern could be detected in frailty as well by analyzing these molecules in 50 frail and 136 robust subjects. Additionally, a subgroup of these subjects (15 frail and 30 robust) underwent a 12-week program based on a multicomponent exercise protocol (VIVIFRAIL) consisting of resistance training, gait retraining, and balance training. After the program, serum miRNAs concentration was measured again, to verify whether the physical activity had an effect on their concentration. Moreover, clinical characteristics and indicators of physical performance of all subjects were compared before and after intervention to verify the effect of the VIVIFRAIL program.

RESULTS

At the end of the multicomponent exercise program, Short Physical Performance Battery (SPPB) score as well right and left handgrip (p < 0.05) were significantly increased in frail subjects; right and left handgrip significantly were increased also in robust subjects (p < 0.05). Interestingly, the variation of SPPB was significantly higher in frail compared to robust subjects (p < 0.0001). Moreover, at the end of the program, in frail compared to robust subjects: miR-451a serum concentration was significantly increased (frail: 6.59 × 10⁴; 1.12 × 10⁴-2.5 × 10⁵ c/ng; robust: 2.31 × 10⁴; 1.94 × 10³-2.01 × 10⁵ c/ng) (p < 0.05); and 2) miR-93-5p and miR-495-3p serum concentration was reduced, whereas that of miR-155-5p was significantly increased (p < 0.05 in both cases). Serum concentration of miR-93-5p and miR-495-3p was decreased, and that of miR-155-5p was increased at the end of the program in robust subjects alone, statistical significance being reached for miR-93-5p alone (p = 0.02).

CONCLUSION

These results suggest that serum miR-451a should be investigated as a potential biomarker for frailty and show that the VIVIFRAIL multicomponent program modulates circulatory miRNAs expression, at least in older adults.

miR-23a-3p and miR-181a-5p modulate SNAP-25 expression

SNAP-25 protein is a key protein of the SNARE complex that is involved in synaptic vesicles fusion with plasma membranes and neurotransmitter release, playing a fundamental role in neural plasticity. Recently the concentration of three specific miRNAs-miR-27b-3p, miR-181a-5p and miR-23a-3p -was found to be associated with a specific SNAP-25 polymorphism (rs363050). in silico analysis showed that all the three miRNAs target SNAP-25, but the effect of the interaction between these miRNAs and the 3'UTR of SNAP-25 mRNA is currently unknown. For this reason, we verified in vitro whether miR-27b-3p, miR-181a-5p and miR-23a-3p modulate SNAP-25 gene and protein expression. Initial experiments using miRNAs-co-transfected Vero cells and SNAP-25 3'UTR luciferase reporter plasmids showed that miR-181a-5p (p≤0.01) and miR-23a-3p (p<0.05), but not miR-27b-3p, modulate the luciferase signal, indicating that these two miRNAs bind the SNAP-25 3'UTR. Results obtained using human oligodendroglial cell line (MO3.13) transfected with miR-181a-5p or miR-27b-3p confirmed that miR-181a-5p and miR-23a-3p regulate SNAP-25 gene and protein expression. Interestingly, the two miRNAs modulate in an opposite way SNAP-25, as miR-181a-5p significantly increases (p<0.0005), whereas miR-23a-3p decreases (p<0.0005) its expression. These results for the first time describe the ability of miR-181a-5p and miR-23a-3p to modulate SNAP-25 expression, suggesting their possible use as biomarkers or as therapeutical targets for diseases in which SNAP-25 expression is altered.

Shared and Divergent Epigenetic Mechanisms in Cachexia and Sarcopenia

Significant loss of muscle mass may occur in cachexia and sarcopenia, which are major causes of mortality and disability. Cachexia represents a complex multi-organ syndrome associated with cancer and chronic diseases. It is often characterized by body weight loss, inflammation, and muscle and adipose wasting. Progressive muscle loss is also a hallmark of healthy aging, which is emerging worldwide as a main demographic trend. A great challenge for the health care systems is the age-related decline in functionality which threatens the independence and quality of life of elderly people. This biological decline can also be associated with functional muscle loss, known as sarcopenia. Previous studies have shown that microRNAs (miRNAs) play pivotal roles in the development and progression of muscle wasting in both cachexia and sarcopenia. These small non-coding RNAs, often carried in extracellular vesicles, inhibit translation by targeting messenger RNAs, therefore representing potent epigenetic modulators. The molecular mechanisms behind cachexia and sarcopenia, including the expression of specific miRNAs, share common and distinctive trends. The aim of the present review is to compile recent evidence about shared and divergent epigenetic mechanisms, particularly focusing on miRNAs, between cachexia and sarcopenia to understand a facet in the underlying muscle wasting associated with these morbidities and disclose potential therapeutic interventions.

A Genome-Wide Association Study Identifies Novel Risk Loci for Sarcopenia in a Taiwanese Population

Purpose

A genome-wide association study (GWAS) of sarcopenia unraveled the importance of genetic contribution to decline in muscle. The current study investigated sarcopenia-related single nucleotide polymorphisms (SNPs) in Asian older adults, and further constructed a genotype score that tests the combined effect of these SNPs on risk of sarcopenia.

Patients and Methods

Ninety-six subjects aged 60 or above were recruited from the database of annual geriatric health examination at Tri-Service General Hospital during 2020. Eligible criteria included: 1) not having severe comorbidities; 2) agreed to join the Taiwan Precision Medicine Initiative project; and 3) having sufficient information of required sarcopenic measurements. Genotype–phenotype association analysis was performed to find SNPs that were significantly associated with each of three sarcopenic indices (low muscle mass, muscle strength, and physical performance). Subsequently, these SNPs comprised a sarcopenia-related genotype score that summed up the number of SNPs carrying unfavorable allele(s).

Results

Twelve SNPs revealed suggestive genome-wide significance with the three sarcopenic indices, and eight of them revealed a relationship with more than one index. Low muscle strength was the item that had the most (eight) related SNPs. Among them, rs10282247 affects cholesterol binding and rs7022373 participates in cellular apoptosis. In addition, higher genotype score demonstrated higher risk of sarcopenia (≥4 points: OR=630.6; 2–3 points: OR=408, p-value<0.001).

Conclusion

Several newly discovered SNPs suggest that genetic contribution plays a part in the pathogenesis of sarcopenia. Further studies are warranted to verify the underlying mechanisms. Moreover, a genotype score provides an estimate of the combined effect of genetic association with sarcopenia, which may modestly improve clinical risk classification.