Inflammation balance in skeletal muscle damage and repair

Maternal exposure to polystyrene nanoplastics during gestation and lactation impaired skeletal growth in progeny mice by inhibiting neutrophil extracellular trap formation

Microplastics and nanoplastics are widely distributed in the natural environment and shown to accumulate in living organisms. While their potential impact on human health has been investigated, significant uncertainties remain regarding their toxic effects and mechanisms of interaction with the human skeletal system. We examined the potential effects of polystyrene nanoplastics (PS-NPs, 100 nm) on skeletal health and the underlying molecular mechanisms using the human RAW264.7 and MC3T3-E1 cell lines as in-vitro models, along with a murine model. Maternal exposure to PS-NPs (10 mg/L) through drinking water during the prenatal and lactational periods led to an increase in osteoblasts, as well as a significant rise in bone mineral density (BMD) and bone content in offspring mice. Exposure to 100 mg/L PS-NPs resulted in a significant reduction in the thickness of the femoral growth plates. Multi-omics analysis revealed that both high (100 mg/L) and low (10 mg/L) maternal PS-NP exposure concentrations disrupted gene expression and metabolic regulation in the skeletal system of offspring mice. Regulatory analysis showed PS-NPs probably induced inflammation and abnormal immune infiltration levels by inhibiting the formation of neutrophil extracellular traps (NETs), especially in 100 mg/L exposure. In in-vitro tests, the PS-NPs dose-relatedly reduced the relative viability of RAW264.7 cells and promoted osteoclast differentiation, but did not affect MC3T3-E1 cells up to 500 mg/L. Our findings demonstrate that maternal exposure to PS-NPs has detrimental effects on skeletal development and function in progeny mice, providing new insights into their toxicological effects on the skeletal system.

Exploration of Pathogenesis and Cutting-Edge Treatment Strategies of Sarcopenia: A Narrative Review

Sarcopenia a progressive and multifactorial musculoskeletal syndrome characterized by loss of muscle mass and function, poses a significant global health challenge, particularly in aging populations. Epidemiological studies reveal that sarcopenia affects approximately 5-10% of the general population, with prevalence rates escalating dramatically after age 60 to reach 10-27% in older adults. This age-associated increase contributes significantly to healthcare burdens by elevating risks of disability, frailty, and mortality. Despite its profound impact, current clinical approaches to sarcopenia remain limited. While resistance exercise and protein supplementation form the cornerstone of management, their efficacy is often constrained by poor long-term adherence and variable individual responses, highlighting the urgent need for more comprehensive and personalized treatment strategies. The pathogenesis of sarcopenia is complex and influenced by various factors, including aging, inflammation, nutritional deficits, physical inactivity, and mitochondrial dysfunction. However, the precise molecular mechanisms underlying this condition are still not fully understood. Recent research has made significant strides in elucidating the intricate mechanisms contributing to sarcopenia, revealing novel insights into its molecular and cellular underpinnings. Notably, emerging evidence points to the pivotal role of mitochondrial dysfunction, altered myokine profiles, and neuromuscular junction degeneration in sarcopenia progression. Additionally, breakthroughs in stem cell therapy, exosome-based treatments, and precision nutrition offer promising avenues for clinical intervention. This review aims to synthesize the latest advancements in sarcopenia research, focusing on the novel contributions to its pathogenesis and treatment strategies. We explore emerging trends such as the role of cellular senescence, epigenetic regulation, and targeted therapeutic interventions that could reshape future approaches to managing sarcopenia. By highlighting recent breakthroughs and cutting-edge research, we hope to advance the understanding of sarcopenia and foster the translation of these findings into effective clinical therapies.

Systemic Inflammation and Disruption of the Local Microenvironment Compromise Muscle Regeneration: Critical Pathogenesis of Autoimmune-Associated Sarcopenia

Unlabelled

Sarcopenia is defined by age-related reductions in muscle mass, strength, and physiological function, and it is especially prevalent among individuals with autoimmune diseases. Autoimmune disorders, characterized by immune dysregulation, cause systemic inflammation and damage to multiple tissues through unregulated immune activity. Research indicates that autoimmune diseases negatively impact skeletal muscle functions and may worsen the progression of sarcopenia. This viewpoint comprehensively discusses the pathogenesis and potential mechanism of sarcopenia in 3 autoimmune diseases: inflammatory bowel disease, rheumatoid arthritis, and type 1 diabetes mellitus. Mechanistically, chronic immune microenvironment alterations induce compartment-specific redistribution of leukocyte subsets and cytokine networks. These perturbations disrupt critical signaling pathways governing muscle protein synthesis, satellite cell activation, and mitochondrial bioenergetics, leading to impaired regeneration and accelerated sarcopenia progression. By delineating shared and distinct pathomechanisms across these models, this analysis reframes our understanding of immune-mediated muscle wasting. Beyond mechanistic insights, it establishes a translational framework for targeted therapies and highlights emerging research directions bridging immunology and age-related musculoskeletal decline.

Advanced Biomimetic Materials in the Prevention of Tendon Adhesions: Design, Preparation, and Application of Hydrogel and Electrospun fiber Membranes

Tendon adhesion formation results from a fibrotic process between the tendon and surrounding tissues, typically occurring after tendon injury or surgery. This condition significantly impacts the quality of life and motor function. Currently, treating adhesions following the repair of injured tendons remains challenging and is a prominent clinical issue that needs to be addressed. This review compiles the existing pathophysiological mechanisms underlying tendon adhesion formation, with a particular focus on the critical roles of inflammation and inflammatory pathways, growth factors and their associated pathways, as well as peritendinous cellular behaviors in promoting adhesion formation. Furthermore, this paper is dedicated to summarizing the evaluation of hydrogels and electrospun fiber membranes as anti-adhesion materials, emphasizing their design, preparation, and application. Additionally, the success of composite patches created by combining these two materials in preventing tendon adhesions is reviewed, which demonstrates the broad applicability of the hydrogel and electrospun film combination. Finally, the review provides insights into future directions for preventing tendon adhesion formation, focusing on material structure and functional design.

Targeting Muscle Regeneration with Small Extracellular Vesicles from Adipose Tissue-Derived Stem Cells-A Review

Extracellular vesicles (EVs) are membrane-bound structures released by cells carrying diverse biomolecules involved in intercellular communication. Small EVs are abundant in body fluids, playing a key role in cell signaling. Their natural occurrence and therapeutic potential, especially in the context of muscular disorders, make them a significant area of research. Sarcopenia, characterized by progressive muscle fiber loss, represents a pathological state in which EVs could offer therapeutic benefits, reducing morbidity and mortality. Recent studies have proposed an interplay between adipose tissue (AT) and skeletal muscle regarding sarcopenia pathology. AT dysregulation, as seen in obesity, contributes to skeletal muscle loss in a multifactorial way. While AT-derived stem cell (ATDSC) small EVs have been implicated in musculoskeletal homeostasis, their precise action in muscle regeneration remains incompletely understood. In this context, ATDSC-derived small EVs can stimulate skeletal muscle regeneration through improved proliferation and migration of muscle cells, enhancement of muscular perfusion, improvement of tendon and nerve regeneration, stimulation of angiogenesis, and promotion of myogenic differentiation. However, they can also increase skeletal muscle loss. Notably, this is the first comprehensive review to systematically examine the role of ATDSC-derived small EVs in sarcopenia.

Artificial Intelligence-Assisted Muscular Ultrasonography for Assessing Inflammation and Muscle Mass in Patients at Risk of Malnutrition

BACKGROUND

Malnutrition, influenced by inflammation, is associated with muscle depletion and body composition changes. This study aimed to evaluate muscle mass and quality using Artificial Intelligence (AI)-enhanced ultrasonography in patients with inflammation.

METHODS

This observational, cross-sectional study included 502 malnourished patients, assessed through anthropometry, electrical bioimpedanciometry, and ultrasonography of the quadriceps rectus femoris (QRF). AI-assisted ultrasonography was used to segment regions of interest (ROI) from transversal QRF images to measure muscle thickness (RFMT) and area (RFMA), while a Multi-Otsu algorithm was used to extract biomarkers for muscle mass (MiT) and fat mass (FatiT). Inflammation was defined as C-reactive protein (CRP) levels above 3 mg/L.

RESULTS

The results showed a mean patient age of 63.72 (15.95) years, with malnutrition present in 82.3% and inflammation in 44.8%. Oncological diseases were prevalent (46.8%). The 44.8% of patients with inflammation (CRP > 3) exhibited reduced RFMA (2.91 (1.11) vs. 3.20 (1.19) cm2, p < 0.01) and RFMT (0.94 (0.28) vs. 1.01 (0.30) cm, p < 0.01). Muscle quality was reduced, with lower MiT (45.32 (9.98%) vs. 49.10 (1.22%), p < 0.01) and higher FatiT (40.03 (6.72%) vs. 37.58 (5.63%), p < 0.01). Adjusted for age and sex, inflammation increased the risks of low muscle area (OR = 1.59, CI: 1.10-2.31), low MiT (OR = 1.49, CI: 1.04-2.15), and high FatiT (OR = 1.44, CI: 1.00-2.06).

CONCLUSIONS

AI-assisted ultrasonography revealed that malnourished patients with inflammation had reduced muscle area, thickness, and quality (higher fat content and lower muscle percentage). Elevated inflammation levels were associated with increased risks of poor muscle metrics. Future research should focus on exploring the impact of inflammation on muscles across various patient groups and developing AI-driven biomarkers to enhance the diagnosis, monitoring, and treatment of malnutrition and sarcopenia.

Physiological and Metabolic Responses of Mongolian Horses to a 20 km Endurance Exercise and Screening for New Oxidative-Imbalance Biomarkers

The traditional horse industry has undergone a remarkable evolution, with horse racing emerging as a prominent and pivotal economic driver within the sector. Among the various breeds, Mongolian horses, renowned for their exceptional endurance and speed, occupy a significant position in the horse industry. To investigate their homeostasis mechanisms during and after a 20 km endurance exercise and identify novel oxidative-imbalance markers, we selected 12 two-year-old horses and collected blood samples at various time points before, during (at 5, 10, 15, and 20 km), and after the exercise (at 1, 2, 4, and 6 h post-exercise). These samples were analyzed for haematology, blood biochemistry, antioxidant enzyme activities, and liquid chromatography-mass spectrometry (LC-MS) metabolomics. Our results revealed significant changes in heart rate, speed, blood cells, and biochemical markers throughout the exercise. Antioxidant indicators decreased, while malondialdehyde increased, indicating oxidative imbalance post-exercise. Metabolomics analysis identified 122 differential metabolites, including uric acid and L-tyrosine, which were enriched in pathways related to energy metabolism. Uric acid and tyrosine correlated positively with serum creatine kinase, suggesting their potential as markers of oxidative-imbalance injury. These findings elucidate the mechanisms of endurance adaptability in Mongolian horses and provide a theoretical basis for mitigating oxidative imbalance, enhancing horse performance, and promoting the sustainable development of the equine industry.

Chondroitin sulfate and Cys-Ala-Gly peptides coated ZE21B magnesium alloy for enhanced corrosion resistance and vascular compatibility

Coronary stents are widely used in the interventional treatment of cardiovascular disease. Biodegradable magnesium alloy stents are ideal candidates to replace traditional non-biodegradable stents due to their excellent mechanical properties and biodegradation. However, too fast degradation and poor biocompatibility limit the further clinical application of magnesium alloy stents. Herein, a composite coating consisting of an MgF2 layer, PDA layer, ChS, and CAG peptide was constructed on the Mg-Zn-Y-Nd (ZE21B) alloy to enhance its corrosion resistance, hemocompatibility, and cytocompatibility. The MgF2 and PDA layers in the composite coating could collectively enhance the corrosion resistance of ZE21B alloy, and the ChS and CAG peptides in the composite coating could improve the anticoagulant and pro-endothelialization capacity of ZE21B alloy. The corrosion current density of the modified ZE21B alloy was much lower than that of bare ZE21B alloy, proving the better corrosion resistance. Moreover, the excellent hemocompatibility of modified ZE21B alloy was verified by the lower levels of hemolysis rate, fibrinogen adsorption and denaturation, and platelet adhesion and activation. Furthermore, the composite coating could selectively promote the adhesion, proliferation, migration, and competitive growth of endothelial cells rather than smooth muscle cells on the ZE21B alloy owing to the synergistic biological effects of ChS and CAG peptides. The ChS/CAG modified samples also exhibited excellent biosafety and histocompatibility in vivo implantation experiments. The composite coating significantly improved the corrosion resistance and biocompatibility of ZE21B alloy, and provided a simple and effective strategy for developing degradable vascular stents.

Glycations on Decellularized Muscle Matrix Reduce Muscle Regeneration and Increase Inflammation

Volumetric muscle loss (VML) due to traumatic injury results in the abrupt loss of contractile units, stem cells, and connective tissue, leading to long-term muscle dysfunction and reduced regenerative potential. Muscle connective tissue contains a proregenerative extracellular matrix (ECM), and our lab harnesses the regenerative capacity of decellularized muscle matrix (DMM) to treat VML, a condition with limited treatment options. However, a major limitation is that muscle often comes from aged donors. Previous work from our lab showed that aged donor muscle contains higher levels of advanced glycation end-product (AGE) cross-links compared to muscle from younger donors. This study aimed to determine whether increased AGE cross-links reduce the regenerative capacity of DMM. To test this, we first generated AGEs in DMM with direct D-ribose incubation. We then removed ∼35% of the gastrocnemius muscle in a model and treated it with either AGE-DMM or standard DMM (no AGEs), comparing results to controls. Although muscle force results remained unchanged between AGE-DMM and DMM, AGEs led to reduced muscle mass in histological sections, fewer fibers, and smaller fiber diameters. AGEs also increased collagen levels in histology, but protein assays showed reduced collagen production. We investigated the canonical receptor for AGEs, the receptor for AGEs (RAGE), and found elevated levels in AGE-treated VML compared to DMM alone, along with increased levels of the noncanonical receptor galectin-3. Both RAGE and galectin-3 are associated with inflammation, and proteomics revealed higher inflammatory markers in AGE-treated muscle than in DMM alone. In conclusion, our data suggest that AGEs impair the regenerative potential of DMM, highlighting the importance of considering donor age when sourcing muscle for DMM therapies. Impact Statement This study investigates advanced glycation end-product cross-links in skeletal muscle extracellular matrix (ECM) as a way to model its deleterious effects on muscle regeneration in vivo. We demonstrate here that ECM glycations reduce muscle regeneration, enhance inflammatory markers, reduce ECM protein production, and proteomic analysis identified unique targets that could be explored in future research endeavors.

Pulsed Radiofrequency Alleviates Acute Soft Tissue Injury in Rats by Regulating the TNF/mTOR Signaling Pathway

Objective: Acute traumatic muscle injuries are common and result in substantial loss of time and risk of recurrence. Pulsed radiofrequency (PR) is a strategy that has been gradually adopted for treating muscle injuries in clinical practice. However, the molecular mechanism underlying its therapeutic effects is currently unclear. Materials and Methods: In this study, we screened the gene expression profiles of rats with muscle contusion obtained from the online dataset GSE162565. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of the differentially expressed genes were conducted. Further, we established an acute soft tissue injury (ASTI) rat model and applied PR treatment. Muscle swelling rate analysis, malondialdehyde (MAD) and superoxide dismutase (SOD) content, inflammatory cytokine release, and hematoxylin and eosin staining of the gastrocnemius muscles of ASTI and ASTI + PR rats were performed, and the results were compared with those of control rats. Further, we evaluated the gene expression of Ccl1, interleukin-6 (IL-6), nuclear factor-kappa-B-inhibitor alpha (Nfkbia), Akt1, Jun, Fos, and Caps3 in the model and PR-treated groups, all of which are key genes in the tumor necrosis factor (TNF)/mechanistic target of rapamycin (mTOR) signaling pathway according to the KEGG analysis. Results: The results revealed that 52 genes involved in the TNF/mTOR signaling pathway were closely associated with ASTI progression in rats. PR treatment significantly reduced the malondialdehyde content but increased the SOD content in ASTI model rat muscles, efficiently alleviated muscle contusions and reduced TNF-α and IL-1β production. Moreover, PR treatment significantly decreased Ccl1, IL-6, and Nfkbia expression but increased Akt1, Jun, Fos, and Caps3 levels in ASTI models. These data indicate that PR alleviated ASTI in rats by mediating redox homeostasis and the inflammatory response, which might be modulated by the TNF/mTOR signaling pathway. Conclusions: Thus, this study contributes to the understanding of ASTI progression and provides more substantial information about the genetic mechanism underlying the therapeutic effects of PR on ASTI.

Effectiveness of Microwave Therapy Combined with Berberine /GelMA via COX-2/IL-1β Pathway to Treat Skeletal Muscle Injury: An in vivo Study in Rats

Introduction

Skeletal muscle injuries are short-term, that occur in people who play sports and train. Regular exercise and sports populations undergo repetitive tearing and regeneration of skeletal muscle, in which muscle damage is a necessary component to produce an oxidative inflammatory response and tissue reconstruction. The primary goals of treating this illness are to reduce the disease process cycle and get rid of symptoms like swelling and inflammation at the site of localized injury. Berberine (BBR) has several pharmacological effects, including anti-inflammatory, anti-tumor, and anti-arrhythmic properties.

Methods

In order to treat skeletal muscle injuries, a safe and non-toxic nanogel (BBR/GelMA) was developed for efficient berberine delivery. It also investigated whether BBR/GelMA had anti-inflammatory properties via the NF-κB pathway. Microwave irradiation was added to promote the uptake of BBR in BBR/GelMA by injured skeletal muscle and to accelerate the process of injury recovery.

Results

It turns out that the survival rates of NIH313 and L929 cells decreased to varying degrees in GelMA loaded with different concentrations of BBR, but the survival rates of the two cell lines were the highest at a concentration of 0.125 mg/mL.

Conclusion

In this experiment, the inhibitory effect of BBR/GelMA on inflammation was studied. After NIH-313 and L929 cells were treated with GelMA loaded with different doses of BBR, it was found that the concentration of BBR/0.5 mg/mL had the best inhibitory effect on these two inflammation-inducing cell lines, and this inhibitory effect was related to the drug loading concentration. On the other hand, BBR/GelMA and microwave therapy can play an anti-inflammatory and repairing role in skeletal muscle through NF-κB pathway. In addition, microwave can accelerate the diffusion of BBR in BBR/GelMA within injured skeletal muscle, speeding up the healing process after skeletal muscle injury and shortening the disease cycle.

Identification of Hub Genes for Dexmedetomidine Alleviation of Limb Ischemia-Reperfusion-Induced Lung Injury in Rats by Transcriptomic

Background

Limb ischemia-reperfusion (LIR), a prevalent clinical condition, frequently precipitates acute lung injury (ALI). Dexmedetomidine (DEX), a selective alpha2-adrenergic receptor agonist, mitigates LIR-induced ALI. However, its underlying mechanisms remain incompletely elucidated. This study aimed to identify hub genes implicated in DEX-mediated protection against LIR-ALI in rats.

Methods

Sprague-Dawley rats were allocated into five groups (n = 3 per group): Sham (femoral artery exposure without occlusion), LIR, LIR + DEX, LIR + Inhibitor, and LIR + DEX + Inhibitor. LIR was induced by clamping the femoral arteries for 3 hours, followed by reperfusion. DEX (50 μg/kg) or Atipamezole (alpha2-receptor inhibitor, 250 μg/kg) was administered prior to ischemia. Lung injury was evaluated via hematoxylin-eosin staining, wet/dry ratio assessment, and quantification of IL-1beta, TNF-alpha, malondialdehyde (MDA), and superoxide dismutase (SOD) levels. RNA sequencing was performed to identify differentially expressed genes (DEGs), followed by functional enrichment analysis, protein-protein interaction (PPI) network construction, and hub gene identification. Gene-gene interaction (GGI) networks were established. Polymerase chain reaction (PCR) and enzyme linked immunosorbent assay (ELISA) validation was conducted.

Results

LIR induced severe lung injury and inflammation, both of which were attenuated by DEX pretreatment. RNA sequencing identified 2,302 DEGs1, 471 DEGs2, 340 DEGs3, and 1,407 DEGs4. After intersection and subtraction analyses, 255 DEX-associated DEGs (DEGs-Dex) and 290 inhibitor-associated DEGs (DEGs-In) were identified, with enrichment in Wnt/PI3K-Akt signaling (DEX) and glycerolipid/butanoate metabolism (In). Nine Hub-Dex genes and four Hub-In genes were identified, among which Selp and Tars1 exhibited a strong positive correlation (correlation = 0.55, P < 0.05). Six hub genes (Tars1, Atf4, Ep300, Sphk1, AABR07051376.1, and Mmp9) were validated.

Conclusion

Six hub genes associated with DEX-mediated protection against LIR-ALI were identified, providing mechanistic insights and potential therapeutic targets for intervention.

Immune Dysregulation in Depression and Anxiety: A Review of the Immune Response in Disease and Treatment

Rates of depression and anxiety have increased significantly in recent decades, with many patients experiencing treatment-resistant symptoms. Beyond psychiatric manifestations, these conditions are associated with heightened risks of suicide, cardiovascular disease, chronic pain, and fatigue. Emerging research suggests that neuroinflammation, immune dysregulation, and hypothalamic-pituitary-adrenal axis dysfunction contribute to their pathophysiology, often interacting bidirectionally with stress. While current first-line treatments primarily target neurotransmitter imbalances, many patients do not achieve symptom resolution, highlighting the need for novel approaches. This review explores the role of immune dysfunction, cytokine activity, and neurotransmitter interactions in depression and anxiety. Additionally, we examine how existing pharmacological and non-pharmacological interventions influence inflammation and immune responses. Understanding these mechanisms may pave the way for more integrative treatment strategies that combine immune modulation with traditional psychiatric therapies.

Gut microbes-muscle axis in muscle function and meat quality

The concept of the gut microbes-muscle axis underscores the impact of intestinal microbiota on the muscular system, an area that is increasingly coming to light. However, current interpretations and applications of this concept remain underdeveloped. In this review, we concluded and discussed factors, such as short-chain fatty acids, amino acids, vitamins, bile acids, antibiotics, cytokines, hormones, and extracellular vesicles that mediate gut microbes-muscle crosstalk and influence the gut microbes-muscle axis. Additionally, we examined how the gut microbes-muscle axis affects muscle mass, muscle strength, muscle metabolism, as well as muscle oxidative and immune status. Furthermore, we reviewed the influence of the microbes-muscle axis on muscle fiber type transition, muscle fat deposition, and meat quality. These insights illuminate the potential mechanisms by which the gut microbes-muscle axis operates in humans and animals. Thus, this review provides a theoretical foundation for future research and offers practical guidance for its application in biomedical and livestock industries.

Effect of clove flower extract ( ) administration timing on skeletal muscle damage induced by eccentric exercise: An in vivo study

Eccentric exercise often leads to oxidative stress, inflammation, and muscle damage that impair athletic performance. To counter these adverse effects, clove flower extract (Syzygium aromaticum) offers promising potential as a natural remedy to promote muscle repair with its potent antioxidant and anti-inflammatory properties. The aim of this study was to assess the effects of clove flower extract administration timing on oxidative stress and inflammatory responses in skeletal muscle damage induced by acute eccentric exercise in mice. This study used a post-test-only control group design, involving 35 male mice (Mus musculus, Balb/c) randomly divided into five groups: a healthy control group (HG) with no exercise and no treatment, a negative control group (NG) with exercise but no treatment, T1 group (receiving clove flower extract 24 hours before exercise), T2 group (receiving clove flower extract immediately after exercise), and T3 group (receiving clove flower extract 24 hours after exercise). The treatment groups received a single dose of clove flower extract (500 mg/kg body weight (BW)). The skeletal muscle damage in mice was collected by measuring NADPH oxidase (NOX) and superoxide dismutase (SOD) activities using spectrophotometry, as well as toll-like receptor 4 (TLR4) and interleukin-8 (IL-8) levels using an enzyme-linked immunosorbent assay (ELISA). Moreover, the skeletal muscle damage was analyzed through the histopathological method. Data were analyzed using one-way analysis of variance (ANOVA) followed by Fisher's least significant difference (LSD) tests as a post hoc test. The result showed that clove flower extract significantly reduced NOX (p=0.049) and IL-8 (p=0.032) levels, increased SOD activity (p=0.001), and did not significantly affect TLR4 levels (p=0.532). Moreover, the results showed a significant reduction in muscle damage (p=0.001). The study highlights that the administration of clove flower extract (500 mg/kg BW) 24 hours before exercise, immediately after exercise, or 24 hours after exercise can help prevent muscle damage.

[Cellular models used to study the pathogenesis associated with ocular inflammation in the anterior part of the eye]

Several multifactorial pathologies in ophthalmology that affect the anterior segment of the eye are partly inflammatory. To better understand the role and impact of inflammation in dry eye and corneal healing, many research teams have used in vitro models to mimic different aspects of these diseases. Several in vitro models have been developed to elucidate the signaling cascades involved in pathogenesis. They also offer the experimental flexibility to adjust environmental parameters, facilitating the validation of innovative therapies and the identification of new pharmacological targets. This review focuses on two-dimensional in vitro models, but also highlights the progress made in 3D models obtained by tissue engineering, which mimic inflammation in these ocular pathologies. The origin of the cells (human or animal), their tissue source, the type of cells (epithelial, endothelial, vascular, conjunctival), as well as the various experimental conditions used to mimic an inflammatory aspect according to the stages of progression of these pathologies, are thoroughly reported in this review of the literature.

Dynamic proteome and phosphoproteome profiling reveals regulatory mechanisms in LPS-stimulated macrophage inflammatory responses

Macrophage-mediated acute inflammation is crucial for pathogen clearance and tissue repair, yet the underlying molecular mechanisms remain inadequately understood. The present study focused on the dynamic profiles of the proteome and phosphoproteome of macrophages exposed to lipopolysaccharide within 1 h. Gene Set Enrichment Analysis (GSEA) identified significantly enriched pathways in fatty acid metabolism and translation during the early inflammatory phase. Further trend analysis of the differentially expressed proteins revealed patterns associated with translation regulation such as translation initiation. Importantly, the nascent chain experiment demonstrated no significant changes in overall gene translation levels during this phase. These data indicate that macrophages maintain intracellular protein homeostasis through translational regulation, with post-translational modifications (PTMs) playing a crucial role in the rapid cellular response to pathogen invasion. Phosphorylation is a key PTM that regulates protein functions in almost all cellular processes. Time-resolved phosphoproteome analysis identified 367 differentially expressed phosphopeptides involved in immune-related pathways that resist infection. Additionally, weighted gene co-expression network analysis (WGCNA) discovered core modules that regulate translation-related processes such as RNA export from nucleus. Moreover, conjoint analysis of the proteome and phosphoproteome identified the hub protein EF1B that exhibited the largest fold change and is also involved in translation. Our data not only provide a more comprehensive understanding of the dynamic molecular networks of acute macrophage inflammation but also provide a systematic proteomic resource for further studies.

Virulence expression difference to intestinal cells of different pathogenic Listeria monocytogenes contaminating sausages after simulated digestive tract

This study investigated the difference in survival among Listeria monocytogenes (LM) 10403S (highly pathogenic strain) and M7 (low pathogenic strain) in sausage under a simulated digestive environment, and established intestinal organoids and macrophages co-culture model to further explore the virulence expression difference to intestinal cells between LM 10403S and M7 after in vitro gastrointestinal digestion. Results showed that, compared with LM M7, LM 10403S exhibited a high survival rate during in vitro digestion, which may be due to the increased expression of stress response-related genes. In addition, the expression of virulence genes in LM 10403S was significantly higher than in LM M7 under the gastrointestinal environment. Furthermore, in the intestinal organoids and macrophages co-culture model infected by LM 10403S and M7 after in vitro gastrointestinal digestion, results showed that, compared with the LM M7 group, the LM 10403S group had significantly lower budding rate and significantly higher mortality of organoids. Also, the significantly increased LDH release and inflammatory factors (TNF-α and IL-1β) in the LM 10403S group were observed, and the main virulence genes (iap, inlA, inlB, actA, hly, plcA, and plcB) of 10403S were significantly highly expressed than LM M7 during the cell infection. These results reflected that the reason for the different pathogenicity between LM 10403S and M7 may be due to the high tolerance and the expression of virulence genes than LM M7 during gastrointestinal digestion and cell infection, which would be expected to provide a better understanding of the infection mechanisms among different pathogenic strains of L. monocytogenes in food.

Role of Perinatal Stem Cell Secretome as Potential Therapy for Muscular Dystrophies

Inflammation mechanisms play a critical role in muscle homeostasis, and in Muscular Dystrophies (MDs), the myofiber damage triggers chronic inflammation which significantly controls the disease progression. Immunomodulatory strategies able to target inflammatory pathways and mitigate the immune-mediated damage in MDs may provide new therapeutic options. Owing to its capacity of influencing the immune response and enhancing tissue repair, stem cells' secretome has been proposed as an adjunct or standalone treatment for MDs. In this review study, we discuss the challenging points related to the inflammation condition characterizing MD pathology and provide a concise summary of the literature supporting the potential of perinatal stem cells in targeting and modulating the MD inflammation.

Early detection of muscle wasting assessed by ultrasound and analysis of growth factor and systemic inflammation mediators in critically ill trauma patients: an observational study

PURPOSE

The present study aims to describe initial changes in muscle thickness and composition, muscle growth signaling mediators, and systemic inflammation in critically ill patients after major trauma.

METHODS

This observational study was carried out in a Level-I nonprofit trauma center. Thirty adults requiring mechanical ventilation were assessed within 24 h post-admission. Skeletal muscle wasting was evaluated using ultrasound for muscle thickness and echogenicity along with circulating insulin-like growth factor 1 (IGF-1) and inflammatory cytokines over five consecutive days. Changes over time were assessed using ANOVA repeated-measures analysis with a Bonferroni post-hoc test. Bivariate correlations were evaluated using Pearson or Spearman coefficients.

RESULTS

Over five days, a significant decrease (11%) in rectus femoris thickness (3.91 ± 0.86 to 3.47 ± 0.64, cm, p = 0.01) and an increase (29%) in echogenicity (62.1 ± 13.1 to 80.4 ± 17.3, AU, p < 0.01) were observed among the 30 patients included in this study. Circulating levels of IGF-1 exhibited a 38% reduction (68.8 ± 43.6 to 42.4 ± 29.4, ng/mL, p = 0.01). Furthermore, pro-inflammatory cytokine (IFN-y) increased by 17% (4.83 ± 1.39 to 5.66 ± 1.61, pg./mL, p = 0.02) from day 1 to day 5.

CONCLUSIONS

These findings reveal substantial thickness and muscle composition alterations within 48 h post-admission, worsening over five days. Despite standard rehabilitation care, changes in IGF-1 and IFN-y levels suggest early declines in muscle growth stimulus and increased inflammation.

Plant-Derived Treatments for Different Types of Muscle Atrophy

With the development of medicine and chemistry, an increasing number of plant-derived medicines have been shown to exert beneficial therapeutic on the treatment of various physical and psychological diseases. In particular, by using physical chemistry methods, we are able to examine the chemical components of plants and the effects of these substances on the human body. Muscle atrophy (MA) is characterized by decreased muscle mass and function, is caused by multiple factors and severely affects the quality of life of patients. The multifactorial and complex pathogenesis of MA hinders drug research and disease treatment. However, phytotherapy has achieved significant results in the treatment of MA. We searched PubMed and the Web of Science for articles related to plant-derived substances and muscle atrophy. After applying exclusion and inclusion criteria, 166 and 79 articles met the inclusion criteria, respectively. A total of 173 articles were included in the study after excluding duplicates. The important role of phytoactives such as curcumin, resveratrol, and ginsenosides in the treatment of MA (e.g., maintaining a positive nitrogen balance in muscles and exerting anti-inflammatory and antioxidant effects) has been extensively studied. Unfortunately, MA dose not have to a single cause, and each cause has its own unique mechanism of injury. This review focuses on the therapeutic mechanisms of active plant components in MA and provides insights into the personalized treatment of MA.

Unraveling the transcriptomic effects of leucine supplementation on muscle growth and performance in basketball athletes

Leucine has gained recognition as an athletic dietary supplement in recent years due to its various benefits; however, the underlying molecular mechanisms remain unclear. In this study, 20 basketball players were recruited and randomly assigned to two groups. Baseline exercise performance-assessed through a 282-foot sprint, free throws, three-point field goals, and self-rated practice assessments-was measured prior to leucine supplementation. Participants were then given a functional drink containing either leucine (50 mg/kg body weight) or a placebo for 28 days. After supplementation, the same exercise performance metrics were reassessed. Following leucine supplementation, biceps brachii muscle tissue from both groups was collected for transcriptome sequencing and qPCR verification. Our results suggested that leucine supplementation significantly improved 282-foot sprint performance, reducing times from 17.4 ± 0.9 to 16.2 ± 0.9 seconds in the leucine group, compared to minimal changes in the control group (from 17.3 ± 0.9 to 17.1 ± 0.8 seconds; P = 0.034). For other exercise performance metrics, no significant differences were observed (P > 0.05); however, trends toward improvement were noted. Transcriptomic analysis revealed 3,658 differentially expressed genes (DEGs) between the two groups. These DEGs were enriched in pathways related to immune response (P < 0.0001), positive regulation of cytokine production (P < 0.0001), and neutrophil extracellular trap formation (P < 0.0001), among others. Weighted Gene Co-expression Network Analysis (WGCNA) identified a module (turquoise) strongly associated with muscle growth, with DEGs in this module enriched in cytoskeletal pathways in muscle cells. Gene expression changes (α-tubulin, β-tubulin, CK18, CK8, vimentin, cofilin, gelsolin, profilin, MAP1, MAP2, MAP4, E-cadherin, and N-cadherin) were verified by qPCR. In summary, leucine supplementation improved exercise performance, particularly by significantly reducing sprint times and showing trends of improvement in other performance metrics, including three-point field goals, free throws, and self-rated well-being. Identified DEGs enriched in pathways related to immune response, cytokine production, and cell adhesion. WGCNA highlighted a key module associated with muscle growth, enriched in cytoskeletal pathways. qPCR validation confirmed the upregulation of cytoskeleton-related genes, supporting the transcriptomic findings. These results suggest that leucine enhances muscle adaptation by regulating cytoskeletal dynamics, providing molecular insights into its role in improving athletic performance.

The role of the cyclooxygenase-2 pathway in tissue ischemia and revascularization following skeletal muscle injury induced by bothropic snake venom

Bothrops asper venom (Bav) contains metalloproteinases that disrupt the microvascular system, impairing muscle tissue regeneration after injury. This study investigated the impact of the cyclooxygenase-2 (COX-2) pathway on vascular injury and revascularization in muscle injuries induced by Bav. Mice were injected with Bav into the gastrocnemius muscle and treated with lumiracoxib, a selective COX-2 inhibitor, 30 min, 2 days, and 6 days post-Bav injection. Muscle tissue was analyzed at 24 h, 7 days, and 21 days post-injection. A decrease in COX-2 expression at 24 h post-Bav injection indicated significant necrosis and tissue loss. Both Bav injection and lumiracoxib treatment influenced the decrease of prostaglandin (PG)D2 and PGE2 production. Seven and 21 days post-Bav injections, COX-2 expression increased, along with PGDs levels unaffected by lumiracoxib, indicating that the other isoform COX-1 pathway could contribute to the release of PGs. Bav/lumiracoxib treated animals presented exacerbated limb ischemia, implying that COX-2-derived prostaglandins preserve vessel integrity. CD31, an angiogenesis marker, initially (24 h) decreased post-Bav injection but increased at 7 and 21 days in Bav/lumiracoxib mice, suggesting a down-modulatory role for COX-2-derived prostaglandins in early angiogenesis and tissue regeneration. Vascular endothelial growth factor (VEGF) production rose 7 days post-Bav injection, supporting its role in angiogenesis. Previous treatment with lumiracoxib promoted release of VEGF levels 21 days post-Bav injury showing that the inhibition of COX-2 pathway in the early stage of revascularization stimulates the neovascularization regulated by elevated release of VEGF. Similarly, metalloproteinases (MMPs), such as MMP-9, MMP-10, and MMP-13, crucial for vascular remodeling, were elevated 21 days after Bav/lumiracoxib treatment. In conclusion, the COX-2 pathway is essential to decrease the high grade of ischemia caused by acute injury induced by Bav. However, the decrease of activity in the COX-2 pathway in the first stages of revascularization contributes to the elevated production of key pro-angiogenic mediators that up-regulate the restoration of microvasculature and blood flow in muscle tissue injured by botropic venoms.

Different trend of muscle wasting extracted from computed tomography in patients with severe acute pancreatitis

PURPOSE

The trend of muscle wasting in patients with acute severe and moderately severe pancreatitis (AP) remains unclear. This retrospective study aimed to investigate the trend of skeletal muscle area (SMA) changes and its impact on patients with severe and moderately severe AP.

METHODS

Patients diagnosed with AP who had repeated CT scans after intensive care unit (ICU) admission were included. The patients were categorized into moderately severe AP or severe AP groups. The generalized additive mixed model (GAMM) was used to analyze the SMA trajectories.

RESULTS

A total of 126 patients were included. The patients in the severe AP group had more rapid muscle wasting during the first 3 weeks following ICU admission. The SMA decreased by 1.1 cm2 (95% CI: 1.3 to 0.8) per day in the severe AP group, while the SMA decreased by 0.5 cm2 (95% CI: 0.6 to 0.4) in the moderately severe AP group in the GAMM model. A larger change in the SMA during the first 10 days after admission was significantly associated with prolonged length of hospital stay (LOS) (β = - 0.205, P = 0.036).

CONCLUSIONS

Patients with severe AP experienced more muscle wasting during the first 3 weeks after ICU admission. A larger reduction in the SMA was associated with prolonged LOS.

CLINICAL IMPLICATIONS

Different patterns of muscle wasting were present during the first 3 weeks after ICU admission in moderately severe and severe AP patients. Accordingly, different nutrition and rehabilitation strategies might be employed depending upon the severity of AP.

Assessment of body composition and prediction of infectious pancreatic necrosis via non-contrast CT radiomics and deep learning

Aim

The current study aims to delineate subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), the sacrospinalis muscle, and all abdominal musculature at the L3-L5 vertebral level from non-contrast computed tomography (CT) imagery using deep learning algorithms. Subsequently, radiomic features are collected from these segmented images and subjected to medical interpretation.

Materials and methods

This retrospective analysis includes a cohort of 315 patients diagnosed with acute necrotizing pancreatitis (ANP) who had undergone comprehensive whole-abdomen CT scans. The no new net (nnU-Net) architecture was adopted for the imagery segmentation, while Python scripts were employed to derive radiomic features from the segmented non-contrast CT images. In light of the intrinsic medical relevance of specific features, two categories were selected for analysis: first-order statistics and morphological characteristics. A correlation analysis was conducted, and statistically significant features were subjected to medical scrutiny.

Results

With respect to VAT, skewness (p = 0.004) and uniformity (p = 0.036) emerged as statistically significant; for SAT, significant features included skewness (p = 0.023), maximum two-dimensional (2D) diameter slice (p = 0.020), and maximum three-dimensional (3D) diameter (p = 0.044); for the abdominal muscles, statistically significant metrics were the interquartile range (IQR; p = 0.023), mean absolute deviation (p = 0.039), robust mean absolute deviation (p = 0.015), elongation (p = 0.025), sphericity (p = 0.010), and surface volume ratio (p = 0.014); and for the sacrospinalis muscle, significant indices comprised the IQR (p = 0.018), mean absolute deviation (p = 0.049), robust mean absolute deviation (p = 0.025), skewness (p = 0.008), maximum 2D diameter slice (p = 0.008), maximum 3D diameter (p = 0.005), sphericity (p = 0.011), and surface volume ratio (p = 0.005).

Conclusion

Diminished localized deposition of VAT and SAT, homogeneity in the VAT and SAT density, augmented SAT volume, and a dispersed and heterogeneous distribution of abdominal muscle density are identified as risk factors for infectious pancreatic necrosis (IPN).

Plant-Based Diet and Sports Performance

Recently, interest in plant-based diets has grown significantly, driven by health and environmental concerns. Plant-based diets offer potential health benefits, including decreased risk of cardiovascular disease, weight management, and blood glucose regulation. This diet profile is rich in complex carbohydrates, antioxidants, dietary fiber, and phytochemicals. However, antinutrients in some plant foods can make nutrient absorption difficult, necessitating careful dietary planning. Plant-based diets can also improve sports performance; in addition, they can positively influence the intestinal microbial community, which can promote health and performance. The present study covered a review from 1986 to 2024 and involved an experimental design with human participants. The main objective was to evaluate the impact of plant-based diets on sports performance. Recent research suggests that plant-based diets do not harm athletic performance and may positively impact sports performance by improving blood flow and reducing oxidative stress. These findings have potential clinical significance, particularly for athletes seeking to optimize their physical capabilities through dietary interventions.

Targeting CD36 With EP 80317 Reduces Remote Inflammatory Response to Hind Limb Ischemia-Reperfusion in Mice

Reperfusion of ischemic skeletal muscle triggers oxidative stress and an immediate inflammatory reaction, leading to damage of distant organs such as the lungs. The inflammatory process implicates numerous mediators, including cytokines, chemokines, and arachidonic acid metabolites. In the orchestration of the inflammatory cascade, a critical role is played by the cluster of differentiation-36 receptor (CD36), a scavenger receptor class B protein (SR-B2) which is expressed on macrophages and functions as a Toll-like receptor coreceptor. A mouse model of hind limb ischemia-reperfusion has been used to investigate the interplay between CD36 signaling and remote inflammation: leukocyte recruitment, regulation of the nucleotide-binding domain leucin-rich repeat and pyrin-containing receptor 3 (NLRP3) inflammasome, and release of nuclear factor-kappa B (NF-ĸB) and arachidonic acid metabolites. Levels of reactive oxygen species, inflammatory mediators, and gene expression were measured in blood and lung tissue samples collected from anesthetized mice on which unilateral hind limb ischemia was induced by rubber band constriction for 30 min followed by reperfusion for 3 h. The CD36 modulator EP 80317, a member of the growth hormone releasing peptide 6 family, was employed as a pharmacological agent to mitigate distant lung injury following skeletal limb ischemia-reperfusion. Targeting CD36 on monocytes/macrophages, EP 80317 abated pro-inflammatory signaling and transcriptional activity encompassing lipid and cytokine mediators. Targeting CD36 was shown to offer promise for curtailing tissue injury following hind limb ischemia-reperfusion.

HMGB1, an evolving pleiotropic protein critical for cellular and tissue homeostasis: Role in aging and age-related diseases

Aging is a universal biological process characterized by a progressive, cumulative decline in homeostatic capabilities and physiological functions, which inevitably increases vulnerability to diseases. A number of molecular pathomechanisms and hallmarks of aging have been recognized, yet we miss a thorough understanding of their complex interconnectedness. This review explores the molecular and cellular mechanisms underlying human aging, with a focus on the multiple roles of high mobility group Box 1 protein (HMGB1), the archetypal damage-associated molecular pattern (DAMP) molecule. In the nucleus, this non-histone chromatin-associated protein functions as a DNA chaperone and regulator of gene transcription, influencing DNA structure and gene expression. Moreover, this versatile protein can translocate to the cytoplasm to orchestrate other processes, such as autophagy, or be unconventionally secreted into the extracellular environment, where it acts as a DAMP, combining inflammatory and regenerative properties. Notably, lower expression of HMGB1 within the cell and its heightened extracellular release have been associated with diverse age-associated traits, making it a suitable candidate as a universal biomarker of aging. In this review, we outline the evidence implicating HMGB1 in aging, also in light of an evolutionary perspective on its functional pleiotropy, and propose critical issues that need to be addressed to gauge the value of HMGB1 as a potential biomarker across age-related diseases and therapeutic target to promote healthy longevity.

Effects and mechanisms of APP and its cleavage product Aβ in the comorbidity of sarcopenia and Alzheimer's disease

Sarcopenia and AD are both classic degenerative diseases, and there is growing epidemiological evidence of their comorbidity with aging; however, the mechanisms underlying the biology of their commonality have not yet been thoroughly investigated. APP is a membrane protein that is expressed in tissues and is expressed not only in the nervous system but also in the NMJ and muscle. Deposition of its proteolytic cleavage product, Aβ, has been described as a central component of AD pathogenesis. Recent studies have shown that excessive accumulation and aberrant expression of APP in muscle lead to pathological muscle lesions, but the pathogenic mechanism by which APP and its proteolytic cleavage products act in skeletal muscle is less well understood. By summarizing and analyzing the literature concerning the role, pathogenicity and pathological mechanisms of APP and its cleavage products in the nervous system and muscles, we aimed to explore the intrinsic pathological mechanisms of myocerebral comorbidities and to provide new perspectives and theoretical foundations for the prevention and treatment of AD and sarcopenia comorbidities.

Impact of Alpha-Ketoglutarate on Skeletal Muscle Health and Exercise Performance: A Narrative Review

AKG, a central metabolite in the Krebs cycle, plays a vital role in cellular energy production and nitrogen metabolism. This review explores AKG's potential therapeutic applications in skeletal muscle health and exercise performance, focusing on its mechanisms for promoting muscle regeneration and counteracting muscle atrophy. A literature search was conducted using the PubMed, Web of Science, and Scopus databases, yielding 945 articles published up to 31 October 2024. Of these, 112 peer-reviewed articles met the inclusion criteria and formed the basis of this review. AKG supports muscle recovery by stimulating muscle satellite cells (MuSCs) and macrophage polarization, aiding muscle repair and reducing fibrosis. Additionally, AKG shows promise in preventing muscle atrophy by enhancing protein synthesis, inhibiting degradation pathways, and modulating inflammatory responses, making it relevant in conditions like sarcopenia, cachexia, and injury recovery. For athletes and active individuals, AKG supplementation has enhanced endurance, reduced fatigue, and supported faster post-exercise recovery. Despite promising preliminary findings, research gaps remain in understanding AKG's long-term effects, optimal dosage, and specific pathways, particularly across diverse populations. Further research, including large-scale clinical trials, is essential to clarify AKG's role in muscle health and to optimize its application as a therapeutic agent for skeletal muscle diseases and an enhancer of physical performance. This review aims to provide a comprehensive overview of AKG's benefits and identify future directions for research in both clinical and sports settings.

The Complement System as a Part of Immunometabolic Post-Exercise Response in Adipose and Muscle Tissue

The precise molecular processes underlying the complement's activation, which follows exposure to physical stress still remain to be fully elucidated. However, some possible mechanisms could play a role in initiating changes in the complement's activity, which are observed post-exposure to physical stress stimuli. These are mainly based on metabolic shifts that occur in the microenvironment of muscle tissue while performing its function with increased intensity, as well as the adipose tissue's role in sterile inflammation and adipokine secretion. This review aims to discuss the current opinions on the possible link between the complement activation and diet, age, sex, and health disorders with a particular emphasis on endocrinopathies and, furthermore, the type of physical activity and overall physical fitness. It has been indicated that regular physical activity incorporated into therapeutic strategies potentially improves the management of particular diseases, such as, e.g., autoimmune conditions. Moreover, it represents a favorable influence on immunoaging processes. A better understanding of the complement system's interaction with physical activity will support established clinical therapies targeting complement components.

Mitigative Effect and Mechanism of Caffeic Acid Combined with Umbilical Cord-Mesenchymal Stem Cells on LPS-Induced Mastitis

Mastitis is an inflammation of the mammary gland tissue that can lead to decreased milk production and altered milk composition, carrying serious implications for the safety of dairy products. Although both caffeic acid (CA) and umbilical cord-mesenchymal stem cells (UC-MSCs) showed potential anti-inflammatory and immunomodulatory properties, little is known about their combined roles in treating mastitis. Here, we report the combined effects and mechanisms of CA and UC-MSCs on lipopolysaccharide (LPS)-induced mastitis. Based on the network pharmacological analysis, the potential relevant genes involved in the alleviating effects of CA on LPS-induced mastitis were inferred. In LPS-treated mammary epithelial cells, CA or/and UC-MSC conditioned medium (UC-MSC-CM) inhibited the phosphorylation of p65, p50, p38, IκB, and MKK3/6 proteins and the expression of downstream inflammatory factors TNF-α, IL-1β, IL-6, IL-8, and COX-2. Additionally, CA or/and hydrogel-loaded UC-MSCs also suppressed the activation of the above inflammatory pathway, leading to the alleviation of pathological damages in the LPS-induced mouse mastitis model. UC-MSCs exhibited more significant effects than CA, and the combined treatment of both was more effective. Our study sheds light on the synergistic and complementary effects of CA and UC-MSCs in alleviating mastitis, offering clues for understanding the regulation of the p38-MAPK/NF-κB↔TNF-α signal transduction loop in the tumor necrosis factor (TNF) pathway as a potential mechanism. This study provides a theoretical basis for developing a novel antibiotic alternative treatment of mastitis that may contribute to reducing economic losses in animal husbandry and protecting public health safety.

Regenerative Inflammation: The Mechanism Explained from the Perspective of Buffy-Coat Protagonism and Macrophage Polarization

The buffy-coat, a layer of leukocytes and platelets obtained from peripheral blood centrifugation, plays a crucial role in tissue regeneration and the modulation of inflammatory responses. This article explores the mechanisms of regenerative inflammation, highlighting the critical role of the buffy-coat in influencing macrophage polarization and its therapeutic potential. Macrophage polarization into M1 and M2 subtypes is pivotal in balancing inflammation and tissue repair, with M1 macrophages driving pro-inflammatory responses and M2 macrophages promoting tissue healing and regeneration. The buffy-coat's rich composition of progenitor cells, cytokines, and growth factors-such as interleukin-10, transforming growth factor-β, and monocyte colony-stimulating factor-supports the transition from M1 to M2 macrophages, enhancing tissue repair and the resolution of inflammation. This dynamic interaction between buffy-coat components and macrophages opens new avenues for therapeutic strategies aimed at improving tissue regeneration and managing inflammatory conditions, particularly in musculoskeletal diseases such as osteoarthritis. Furthermore, the use of buffy-coat-derived therapies in conjunction with other regenerative modalities, such as platelet-rich plasma, holds promise for more effective clinical outcomes.

The Effect of Exercise on Immune Response in Population with Increased Risk Factors for Cardiovascular Disease: A Systematic Review

This systematic review aimed to provide information on existing interventional studies that evaluate the efficacy of exercise in populations with increased cardiovascular disease (CVD) risk factors through immune functional perspectives. A literature search was conducted in four databases: PubMed, Scopus, Taylor & Francis and ScienceDirect from January 2012 to February 2023. The articles were screened and evaluated for quality before data were extracted. The review protocol was registered at PROSPERO (CRD42022321704). In total, 18 studies were included for quality appraisal and synthesised evidence indicated that exercise contributes to enhancing the functioning of both innate and adaptive immune responses, potentially serving as an anti-immunosenescent response to exercise in individuals with elevated CVD risk factors. Furthermore, the review emphasised that exercise, irrespective of its type, intensity or mode, was well tolerated by individuals at increased risk for CVD and may have significant implications in generating anti-inflammatory effects.

Emerging Targets and Treatments for Sarcopenia: A Narrative Review

BACKGROUND

Sarcopenia is characterized by the progressive loss of skeletal muscle mass, strength, and function, significantly impacting overall health and quality of life in older adults. This narrative review explores emerging targets and potential treatments for sarcopenia, aiming to provide a comprehensive overview of current and prospective interventions.

METHODS

The review synthesizes current literature on sarcopenia treatment, focusing on recent advancements in muscle regeneration, mitochondrial function, nutritional strategies, and the muscle-microbiome axis. Additionally, pharmacological and lifestyle interventions targeting anabolic resistance and neuromuscular junction integrity are discussed.

RESULTS

Resistance training and adequate protein intake remain the cornerstone of sarcopenia management. Emerging strategies include targeting muscle regeneration through myosatellite cell activation, signaling pathways, and chronic inflammation control. Gene editing, stem cell therapy, and microRNA modulation show promise in enhancing muscle repair. Addressing mitochondrial dysfunction through interventions aimed at improving biogenesis, ATP production, and reducing oxidative stress is also highlighted. Nutritional strategies such as leucine supplementation and anti-inflammatory nutrients, along with dietary modifications and probiotics targeting the muscle-microbiome interplay, are discussed as potential treatment options. Hydration and muscle-water balance are emphasized as critical in maintaining muscle health in older adults.

CONCLUSIONS

A combination of resistance training, nutrition, and emerging therapeutic interventions holds potential to significantly improve muscle function and overall health in the aging population. This review provides a detailed exploration of both established and novel approaches for the prevention and management of sarcopenia, highlighting the need for further research to optimize these strategies.

Population Analysis of Masseter Muscle Tension Using Shear Wave Ultrasonography across Different Disease States

Objective: This study aimed to evaluate the distribution and trends of masseter muscle tension in patients with temporomandibular joint (TMJ) pain, examining gender-specific differences and the impact of various TMJ disorders. Methods: From January 2020 to June 2024, a total of 734 patients presenting with facial pain radiating to the head and neck, localized around and extending from the TMJ, were referred for ultrasonographic examination. After applying exclusion criteria, 535 patients (72.9%) were included in the study. The patient cohort consisted of 343 females (64.1%) and 192 males (35.9%), with muscle tension measured using the Aixplorer ultrasound system equipped with a shear wave device. Data were collected and analyzed across different age groups and TMJ conditions, including "no changes", "exudate", "arthrosis", and "disc displacement". Results: The study found that males exhibited higher muscle tension across all conditions, particularly in the "no changes" (40.4 kPa vs. 32.1 kPa, 25.9% higher) and "exudate" (38.5 kPa vs. 29.7 kPa, 29.6% higher) categories, indicating increased muscle strain and inflammation during middle age. In females, a trend of decreasing muscle tension with age was observed, with a significant reduction from 36.2 kPa in the 20-30 age group to 24.3 kPa in the 60-70 age group (32.9% reduction), suggesting a reduction in muscle mass or strength due to aging. Both genders showed high muscle tension in the presence of exudate, with females peaking in the 40-50 age group at 37.1 kPa and males peaking earlier in the 20-30 age group at 41.2 kPa (10.9% higher in males), highlighting potential gender differences in inflammatory response. In the arthrosis group, males displayed a consistent increase in muscle tension with age, peaking at 37.5 kPa in the 50-60 age group (50.7% increase from the 20-30 age group), while females showed high tension, particularly in the 40-50 age group at 31.0 kPa (82.4% higher compared to the 20-30 age group), indicating the need for targeted joint health interventions in middle-aged women. Conclusions: This study reveals significant gender-specific differences in masseter muscle tension among patients with TMJ pain. Males were found to be more affected by muscle strain and inflammation during middle age, whereas females showed a significant decrease in muscle tension with age. The presence of exudate significantly impacted muscle tension across all age groups for both genders. These findings underscore the importance of tailored clinical interventions and preventive strategies to manage TMJ disorders effectively.

IL-17 signaling pathway: A potential therapeutic target for reducing skeletal muscle inflammation

BACKGROUND

The interleukin-17 (IL-17) signaling pathway is intricately linked with immunity and inflammation; however, the association between the IL-17 signaling pathway and skeletal muscle inflammation remains poorly understood. The study aims to investigate the role of the IL-17 signaling pathway in skeletal muscle inflammation and to evaluate the therapeutic potential of anti-IL-17 antibodies in reducing muscle inflammation.

METHODS

A skeletal muscle inflammation model was induced by cardiotoxin (CTX) injection in C57BL6/J mice. Following treatment with an anti-IL-17 antibody, we conducted a comprehensive analysis integrating single-cell RNA sequencing (scRNA-seq), bioinformatics, enzyme-linked immunosorbent assay (ELISA), immunofluorescence, and Western blot techniques to elucidate underlying mechanisms.

RESULTS

scRNA-seq analysis revealed a significant increase in neutrophil numbers and activity in inflamed skeletal muscle compared to other cell types, including macrophages, T cells, B cells, endothelial cells, fast muscle cells, fibroblasts, and skeletal muscle satellite cells. The top 30 differentially expressed genes within neutrophils, along with 55 chemokines, were predominantly enriched in the IL-17 signaling pathway. Moreover, the IL-17 signaling pathway exhibited heightened expression in inflamed skeletal muscle, particularly within neutrophils. Treatment with anti-IL-17 antibody resulted in the suppression of IL-17 signaling pathway expression, accompanied by reduced levels of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α, as well as decreased numbers and activity of Ly6g+/Mpo+ neutrophils compared to CTX-induced skeletal muscle inflammation.

CONCLUSION

Our findings suggest that the IL-17 signaling pathway plays a crucial role in promoting inflammation within skeletal muscle. Targeting this pathway may hold promise as a therapeutic strategy for ameliorating the inflammatory micro-environment and reducing cytokine production.

Multiple site inflammation and acute kidney injury in crush syndrome

Crush syndrome, which frequently occurs in earthquake disasters, often leads to rhabdomyolysis induced acute kidney injury (RIAKI). Recent findings indicate that systemic inflammatory response syndrome (SIRS) exacerbates muscle collapse, contributing to RIAKI. The purpose of this study is to investigate the involvement of multiple site inflammation, including intraperitoneal, in crush syndrome. In a mouse model of RIAKI, elevated levels of inflammatory mediators such as TNFα, IL-6, myoglobin, and dsDNA were observed in serum and the peritoneal cavity, peaking earlier in the intraperitoneal cavity than in serum or urine. Our previously developed novel peptide inhibiting leukocyte extracellular traps was administered intraperitoneally and blocked all of these mediators in the intraperitoneal cavity and serum, ameliorating muscle damage and consequent RIAKI. Although further studies are needed to determine whether intraperitoneal inflammation associated with muscle collapse can lead to systemic inflammation, resulting in more severe and prolonged muscle damage and renal injury, early suppression of multiple site inflammation, including intraperitoneal, might be an effective therapeutic target.

Chikungunya and Mayaro Viruses Induce Chronic Skeletal Muscle Atrophy Triggered by Pro-Inflammatory and Oxidative Response

Chikungunya (CHIKV) and Mayaro (MAYV) viruses are arthritogenic alphaviruses that promote an incapacitating and long-lasting inflammatory muscle-articular disease. Despite studies pointing out the importance of skeletal muscle (SkM) in viral pathogenesis, the long-term consequences on its physiology and the mechanism of persistence of symptoms are still poorly understood. Combining molecular, morphological, nuclear magnetic resonance imaging, and histological analysis, we conduct a temporal investigation of CHIKV and MAYV replication in a wild-type mice model, focusing on the impact on SkM composition, structure, and repair in the acute and late phases of infection. We found that viral replication and induced inflammation promote a rapid loss of muscle mass and reduction in fiber cross-sectional area by upregulation of muscle-specific E3 ubiquitin ligases MuRF1 and Atrogin-1 expression, both key regulators of SkM fibers atrophy. Despite a reduction in inflammation and clearance of infectious viral particles, SkM atrophy persists until 30 days post-infection. The genomic CHIKV and MAYV RNAs were still detected in SkM in the late phase, along with the upregulation of chemokines and anti-inflammatory cytokine expression. In agreement with the involvement of inflammatory mediators on induced atrophy, the neutralization of TNF and a reduction in oxidative stress using monomethyl fumarate, an agonist of Nrf2, decreases atrogen expression and atrophic fibers while increasing weight gain in treated mice. These data indicate that arthritogenic alphavirus infection could chronically impact body SkM composition and also harm repair machinery, contributing to a better understanding of mechanisms of arthritogenic alphavirus pathogenesis and with a description of potentially new targets of therapeutic intervention.

A Fluorescent Lateral Flow Immunoassay for the Detection of Skeletal Muscle Troponin I in Serum for Muscle Injury Monitoring at the Point of Care

Exercise-induced muscle injury is one of the most common types of sports injuries. Skeletal muscle troponin I (skTnI) serves as an ideal biomarker in assessing such injuries, facilitating timely detection and evaluation. In this study, we develop a fluorescent sandwich lateral flow immunoassay (LFIA) combined with a desktop analyzer for rapid detection of skTnI. Through optimizing the reaction system, the assay achieves a satisfying detection performance, reaching a limit of detection (LOD) of 0.5 ng/mL with a turnaround time of 15 min. The proposed detection platform offers portability, ease of use, and high sensitivity, which facilitates the monitoring of exercise-induced muscle injuries at the point of care. This feature is particularly advantageous for end users, enabling timely detection of sports-related injuries and ultimately enhancing prognosis and sports life.

Low concentrations of TNF-α in vitro transform the phenotype of vascular smooth muscle cells and enhance their survival in a three-dimensional culture system

BACKGROUND

Vascular smooth muscle cells (VSMCs) are commonly used as seed cells in tissue-engineered vascular constructions. However, their variable phenotypes and difficult to control functions pose challenges. This study aimed to overcome these obstacles using a three-dimensional culture system.

METHODS

Calf VSMCs were administered tumor necrosis factor-alpha (TNF-α) before culturing in two- and three-dimensional well plates and polyglycolic acid (PGA) scaffolds, respectively. The phenotypic markers of VSMCs were detected by immunofluorescence staining and western blotting, and the proliferation and migration abilities of VSMCs were detected by CCK-8, EDU, cell counting, scratch, and Transwell assays.

RESULTS

TNF-α rapidly decreased the contractile phenotypic markers and elevated the synthetic phenotypic markers of VSMCs, as well as markedly increasing the proliferation and migration ability of VSMCs under two- and three-dimensional culture conditions.

CONCLUSIONS

TNF-α can rapidly induce a phenotypic shift in VSMCs and change their viability on PGA scaffolds.

Low skeletal muscle mass is associated with inferior preoperative and postoperative shoulder function in elderly rotator cuff tear patients

BACKGROUND

The age-related loss of skeletal muscle mass is an important characteristic of sarcopenia, an increasingly recognized condition with systemic implications. However, its association with shoulder function in elderly patients with rotator cuff tears (RCT) remains unknown. This study aimed to investigate the relationship between low skeletal muscle mass and shoulder function in elderly RCT patients.

METHODS

A retrospective analysis was conducted on RCT patients who underwent chest computed tomography (CT) scans for clinical evaluation. Preoperative CT scan images of the chest were used to calculate the cross-sectional area (CSA) of thoracic muscle at the T4 level. The medical records were reviewed. Shoulder function was assessed using the ASES score and CMS score both preoperatively and at the final follow-up. Data on the preoperative range of motion (ROM) for the affected shoulder, were collected for analysis. Subgroup analyses by sex were also performed.

RESULTS

A total of 283 RCT patients, consisting of 95 males and 188 females, with a mean age of 66.22 ± 4.89(range, 60-95 years) years were included in this retrospective study. The low muscle mass group showed significantly higher level of c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) compared to the normal group(3.75 ± 6.64 mg/L vs. 2.17 ± 2.30 mg/L, p = 0.021; 19.08 ± 12.86 mm/H vs.15.95 ± 10.76 mm/H, p = 0.038; respectively). In the normal group, pre-operative passive ROM, including forward elevation, abduction, lateral rotation, and abductive external rotation, was significantly better than that in the low muscle mass group (127.18 ± 34.87° vs. 89.76 ± 50.61°; 119.83 ± 45.76° vs. 87.16 ± 53.32°; 37.96 ± 28.33° vs. 25.82 ± 27.82°; 47.71 ± 23.56° vs. 30.87 ± 27.76°, all p < 0.01, respectively). Similar results were found in the active ROM of the shoulder. The female low muscle mass group exhibited significantly poorer passive and active ROM (p < 0.05). The post-operative ASES scores and CMS scores of the female low muscle mass group were also statistically worse than those of the female normal group (p < 0.05).

CONCLUSIONS

The results of present study revealed that the low skeletal muscle mass is associated with inferior ROM of the shoulder and per- and post-operative shoulder function, especially for elderly female patients.

Resveratrol and Vitamin D: Eclectic Molecules Promoting Mitochondrial Health in Sarcopenia

Sarcopenia refers to the progressive loss and atrophy of skeletal muscle function, often associated with aging or secondary to conditions involving systemic inflammation, oxidative stress, and mitochondrial dysfunction. Recent evidence indicates that skeletal muscle function is not only influenced by physical, environmental, and genetic factors but is also significantly impacted by nutritional deficiencies. Natural compounds with antioxidant properties, such as resveratrol and vitamin D, have shown promise in preventing mitochondrial dysfunction in skeletal muscle cells. These antioxidants can slow down muscle atrophy by regulating mitochondrial functions and neuromuscular junctions. This review provides an overview of the molecular mechanisms leading to skeletal muscle atrophy and summarizes recent advances in using resveratrol and vitamin D supplementation for its prevention and treatment. Understanding these molecular mechanisms and implementing combined interventions can optimize treatment outcomes, ensure muscle function recovery, and improve the quality of life for patients.

Acute Hormonal and Inflammatory Responses following Lower and Upper Body Resistance Exercises Performed to Volitional Failure

This study aimed to investigate the effects of a single bench press (BP) vs. leg press (LP) resistance training sessions on testosterone, cortisol, C-reactive protein (CRP) interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) concentrations, and creatine kinase (CK) activity in strength-trained males. Eleven strength-trained males participated in a cross-over randomized trial, undergoing two experimental sessions each consisting of five sets of the BP or the LP exercise to volitional failure with a load corresponding to 50% of one-repetition maximum. Blood samples were taken at baseline (BA), immediately post (POST), and 1 h after the cessation of exercise (POST-1). A significant increase in IL-6 concentration from BA to POST-1 was observed during the LP condition (p = 0.004; effect size [ES] = 0.64). Additionally, a significant main effect of time was found for increasing testosterone concentrations from BA to POST exercise (p = 0.014; ES = 0.25). A significantly lower cortisol concentration at POST-1 compared to POST (p = 0.001; ES = 1.02) was noted in the BP condition. Furthermore, a significantly lower cortisol concentration was found at POST-1 in the BP compared to the LP condition (p = 0.022; ES = 1.3). A significant increase in CK activity was reported from BA to POST (p = 0.024; ES = 0.69) and POST-1 (p = 0.045; ES = 0.55) during the LP condition, and from BA to POST-1 (p = 0.014; ES = 0.96) during the BP condition. No significant differences were found in the CRP (p = 0.659) and TNF-α concentrations (p = 0.487). These results suggest that the amount of muscle mass engaged during the resistance exercise may influence the changes in IL-6 and cortisol concentrations. Larger muscle groups, as engaged in the LP, more likely lead to elevated concentrations of IL-6 myokine.

Genome-wide transcriptome analysis reveals that Bisphenol A activates immune responses in skeletal muscle

Cumulative human exposure to the environmental toxin, bisphenol A (BPA), has raised important health concerns in recent decades. However, the direct genomic regulation of BPA in skeletal muscles and its clinical significance are poorly understood. Therefore, we conducted a genome-wide transcriptome analysis after daily oral administration of BPA at the lowest observed adverse-effect level (LOAEL, 50 mg/kg) in male mice for six weeks to explore the gene-expression regulations in skeletal muscle induced by BPA. The primary Gene Ontology terms linked to BPA-dependent, differentially expressed genes at LOAEL comprised adaptive-immune response, positive regulation of T cell activation, and immune system process. The gene-set enrichment analysis disclosed increased complement-associated genes [complement components 3 (C3) and 4B, complement factor D, complement receptor 2, and immunoglobulin lambda constant 2] in the group administered with BPA, with a false-discovery rate of <0.05. Subsequent validation analysis conducted in BPA-fed animal skeletal muscle tissue and in vitro experiments confirmed that BPA induced immune activation, as evidenced by increased levels of C3 and C4α proteins in mice, C2C12 myoblasts, and mouse skeletal muscle cells. In addition, BPA markedly upregulated the transcription of tumor necrosis factor-α (Tnfα) in C2C12 myoblasts and mouse skeletal muscle cells, which was substantially inhibited by 5z-7-oxozeanol and parthenolide, providing further evidence of BPA-induced inflammation in muscle cells. Our bioinformatics and subsequent animal and in vitro validations demonstrate that BPA can activate inflammation in skeletal muscle, which could be a risk factor underlying chronic muscle weakness and wastage.

Association of added sugar intake and its forms and sources with handgrip strength decline among middle-aged and older adults: A prospective cohort study

PURPOSE

The consumption of added sugar has increased rapidly in recent years. Limited knowledge exists regarding the association between added sugar intake and muscle strength, although the latter is a predictor of physical disability in older adults. This study aimed to investigate the association between added sugar intake and longitudinal changes in handgrip strength among middle-aged and elderly Chinese adults.

METHODS

This prospective cohort study included 5298 adults aged 40 years and older (62.6% men) from the TCLSIH (Tianjin Chronic Low-grade Systemic Inflammation and Health) cohort study. Added sugar intake was obtained through a frequency questionnaire containing 100 items of food. Handgrip strength is measured annually using a handheld digital dynamometer. Multivariate linear regression models were used to examine the association between added sugars intake and the annual changes in handgrip strength and weight-adjusted handgrip strength.

RESULTS

In the fully adjusted model, the annual change in handgrip strength for one unit increase in total added sugar, solid added sugar, and liquid added sugar intake was -0.0353 kg, (95% confidence intervals (CI) -0.000148, -0.0000164; P = 0.01), -0.0348 kg (95% CI: -0.000227, -0.0000269; P = 0.01) and -0.0189 kg (95% CI -0.000187, 0.0000338; P = 0.17), respectively. Added sugar from bread and biscuits sources were remarkably associated with a decline in handgrip strength (β = -0.0498; 95%CI -0.00281, -0.000787) and (β = -0.0459; 95%CI 0.00158, 0.00733) (P < 0.01).

CONCLUSIONS

Our data suggest that the higher the intake of solid added sugars, but not liquid sugars, were associated with the declined handgrip strength in the Chinese middle-aged and elderly population. In addition, the consumption of added sugars from bread and biscuits sources was also associated with a decline in grip strength.

Impaired arginine/ornithine metabolism drives severe HFMD by promoting cytokine storm

Introduction

The Hand, Foot and Mouth Disease (HFMD), caused by enterovirus 71 infection, is a global public health emergency. Severe HFMD poses a significant threat to the life and well-being of children. Numerous studies have indicated that the occurrence of severe HFMD is associated with cytokine storm. However, the precise molecular mechanism underlying cytokine storm development remains elusive, and there are currently no safe and effective treatments available for severe HFMD in children.

Methods

In this study, we established a mouse model of severe HFMD to investigate the molecular mechanisms driving cytokine storm. We specifically analyzed metabolic disturbances, focusing on arginine/ornithine metabolism, and assessed the potential therapeutic effects of spermine, an ornithine metabolite.

Results

Our results identified disturbances in arginine/ornithine metabolism as a pivotal factor driving cytokine storm onset in severe HFMD cases. Additionally, we discovered that spermine effectively mitigated the inflammatory injury phenotype observed in mice with severe HFMD.

Discussion

In conclusion, our findings provide novel insights into the molecular mechanisms underlying severe HFMD from a metabolic perspective while offering a promising new strategy for its safe and effective treatment.

Impaired skeletal muscle regeneration in diabetes: From cellular and molecular mechanisms to novel treatments

Diabetes represents a major public health concern with a considerable impact on human life and healthcare expenditures. It is now well established that diabetes is characterized by a severe skeletal muscle pathology that limits functional capacity and quality of life. Increasing evidence indicates that diabetes is also one of the most prevalent disorders characterized by impaired skeletal muscle regeneration, yet underlying mechanisms and therapeutic treatments remain poorly established. In this review, we describe the cellular and molecular alterations currently known to occur during skeletal muscle regeneration in people with diabetes and animal models of diabetes, including its associated comorbidities, e.g., obesity, hyperinsulinemia, and insulin resistance. We describe the role of myogenic and non-myogenic cell types on muscle regeneration in conditions with or without diabetes. Therapies for skeletal muscle regeneration and gaps in our knowledge are also discussed, while proposing future directions for the field.

miR-27b-3p reduces muscle fibrosis during chronic skeletal muscle injury by targeting TGF-βR1/Smad pathway

BACKGROUND

Fibrosis is a significant pathological feature of chronic skeletal muscle injury, profoundly affecting muscle regeneration. Fibro-adipogenic progenitors (FAPs) have the ability to differentiate into myofibroblasts, acting as a primary source of extracellular matrix (ECM). the process by which FAPs differentiate into myofibroblasts during chronic skeletal muscle injury remains inadequately explored.

METHOD

mouse model with sciatic nerve denervated was constructed and miRNA expression profiles between the mouse model and uninjured mouse were analyzed. qRT/PCR and immunofluorescence elucidated the effect of miR-27b-3p on fibrosis in vivo and in vitro. Dual-luciferase reporter identified the target gene of miR-27b-3p, and finally knocked down or overexpressed the target gene and phosphorylation inhibition of Smad verified the influence of downstream molecules on the abundance of miR-27b-3p and fibrogenic differentiation of FAPs.

RESULT

FAPs derived from a mouse model with sciatic nerves denervated exhibited a progressively worsening fibrotic phenotype over time. Introducing agomiR-27b-3p effectively suppressed fibrosis both in vitro and in vivo. MiR-27b-3p targeted Transforming Growth Factor Beta Receptor 1 (TGF-βR1) and the abundance of miR-27b-3p was negatively regulated by TGF-βR1/Smad.

CONCLUSION

miR-27b-3p targeting the TGF-βR1/Smad pathway is a novel mechanism for regulating fibrogenic differentiation of FAPs. Increasing abundance of miR-27b-3p, suppressing expression of TGF-βR1 and inhibiting phosphorylation of smad3 presented potential strategies for treating fibrosis in chronic skeletal muscle injury.

Association between the systemic immune-inflammation index and sarcopenia: a systematic review and meta-analysis

BACKGROUND

Sarcopenia is associated with increased morbidity and mortality. The systemic immune-inflammation index (SII) has been correlated to a variety of disorders. The present study conducted a systematic review and meta-analysis to investigate the relationship between SII and sarcopenia.

METHODS

A literature search was performed in Web of Science, PubMed, Embase, Cochrane Library, CINAHL, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, Wanfang Database, and VIP Chinese Science and Technology Database, from inception to March 2024. Then, the literature quality was assessed. After the heterogeneity test, a random effects or fixed effects model was applied to establish the forest plot, and investigate the relationship between SII and sarcopenia. Then, the sensitivity analysis and publication bias were examined.

RESULTS

Nine articles, which included 18,634 adults, were analyzed. Sarcopenic adults had higher SII levels, when compared to non-sarcopenic adults (standardized mean difference [SMD] = 0.66, 95% confidence interval [CI] = 0.22 - 0.19, p = 0.003). The high SII level was associated to the increased risk of sarcopenia (odds ratio = 1.52, 95% CI = 1.09-2.13, p = 0.01). In addition, the subgroup analysis revealed that the SII levels were higher in the sarcopenic group, when compared to the non-sarcopenic group, in elderly adults, as well as in adults with or without gastrointestinal disorders. The analysis was robust with a low risk of publication bias.

CONCLUSIONS

SII is closely associated to sarcopenia. Sarcopenic adults had elevated SII levels. The high SII level increased the risk of sarcopenia. Large scale multi-center prospective studies are required to validate these study findings.