| Part One A bibliometric analysis-based study of trends in biomarkers of sarcopeniaObjective: This study intends to conduct a bibliometric analysis of the current status and trend analysis of sarcopenia biomarkers to provide a reference for researchers in China to conduct research in this field.Methods: The Web of Science(WOS)database was searched for literature related to sarcopenia biomarkers from January 1,1985 to December31,2022,and the literature was imported into Note Express for de-weighting and screening.The core authors were identified according to Price’s law,and VOSviewer 1.6.18 was used to map the core authors’ collaboration network and high-frequency keyword ranking,and Cite Space 6.1.R6 was used to display keyword clustering and keyword emergence.A total of 360 publications were included.Results: The number of articles published on biomarkers of sarcopenia has been increasing year by year,with the US leading the world in terms of the number of articles published and Italian authors playing a central role in the field.The core author collaboration network showed more intra-team collaboration and less inter-team collaboration in China.The keywords formed nine meaningful clusters,respectively,showing that sarcopenia biomarkers were mainly focused on skeletal muscle,neuromuscular junction,grip strength and cachexia.Conclusions: Subsequent scholars are needed to expand the study of sarcopenia biomarkers,to explore in depth their mechanisms of action and diagnostic value in sarcopenia,and to provide new ideas and experimental basis for the discovery and diagnosis of sarcopenia in China.Part Two Bioinformatics-based biomarker study of sarcopeniaObjective: To explore the role of inflammation in sarcopenia using a bioinformatics approach and to further attempt to identify immune-related genes as diagnostic biomarkers in patients with sarcopenia.Methods: The sarcopenia expression profile datasets GSE111006,GSE111010 and GSE111016 were downloaded from the GEO database using the R package.Immune-related gene data were downloaded from the Imm Port database.Screening and validation of diagnostic markers for sarcopenia using LASSO logistic regression and SVM-RFE algorithms.Results: A total of 400 differential genes were obtained in the combined GSE111006 and GSE111016 datasets,of which 316 were up-regulated and 84 were down-regulated,at a criterion of P < 0.05.The DEGs and 2483 IRGs were further intersected to obtain 25 DIRGs,mainly involved in cytokine-cytokine receptor interactions,viral protein interactions with cytokines and cytokine receptors,and Rap1 signaling pathway.A total of 12 genes were identified as diagnostic markers for sarcopenia after lasso regression screening,and then 6 diagnostically relevant genes(S100A14,TNFSF11,CDH1,IGLV5-45,ANGPT4,DCD6)were obtained after taking the intersection with the SVM-RFE algorithm,which reached high levels in the validation set(AUC = 0.74),indicating that the six diagnostic genes have high diagnostic value.Conclusions: In this study,through bioinformatics analysis of 80 samples from the GEO database,six key genes,S100A14,TNFSF11,CDH1,IGLV5-45,ANGPT4 and DCD,were identified as immune-related biomarkers for the diagnosis of sarcopenia,providing some basis for exploring the relationship between sarcopenia and immune genes.Part Three Amino acid profile study in a community-based elderly sarcopenic populationObjective: To compare the differences in serum amino acid concentrations between elderly people with possible sarcopenia and normal controls in our community,and to explore the significance of serum amino acid levels as biomarkers in the community elderly sarcopenic population.Methods: A total of 231 community-dwelling older adults were recruited for cross-sectional analysis in this study.Study subjects were diagnosed with possible sarcopenia according to the Asian Working Group on Sarcopenia2019(AWGS2019)criteria diagnosis.A comprehensive investigative assessment was conducted in this study,including assessment of grip strength,sit-up tests,body composition analysis and serum amino acid concentrations,including concentrations of 19 amino acids.Hematological indicators including hemoglobin,blood glucose and C-reactive protein were also measured.The relationship between sarcopenia and amino acid profile was analysed using methods such as multiple linear regression analysis.Results: Seventy-eight of the 231 study participants were likely to have sarcopenia,158 women and 73 men.Seventy-eight of the study subjects were in the possible sarcopenia group.Analysis of variance showed that those with probable sarcopenia were significantly older,had a higher risk of malnutrition in the non-muscular reduction group and had lower cognitive status scores than the non-muscular reduction group.In addition,blood glucose(P = 0.007),total cholesterol(P = 0.011)and low-density lipoprotein(P = 0.015)were found to be higher in the probable sarcopenic group than in the non-sarcopenic group.Physical examination and body composition analysis of the study subjects revealed that grip strength was lower in the sarcopenic group than in the non-sarcopenic group,and 6m step speed and 5 sit-up test times were higher in the sarcopenic group than in the control group,with statistically significant differences(P < 0.001).Meanwhile,the results of body composition analysis of the study subjects showed that the phase angle and skeletal muscle mass index of the probable sarcopenia group were significantly lower than those of the non-sarcopenia group(P < 0.001).However,there were no significant differences between the two groups in terms of BMI,body fat percentage and fat-free mass.Multiple linear regression analysis revealed a possible association between sarcopenia and lower serum leucine and isoleucine concentrations.Conclusion: Sarcopenia is associated with leucine and isoleucine concentrations,suggesting that leucine and isoleucine may be biomarkers for the development of sarcopenia.Part Four Association Between Sarcopenia and Cognitive Function in older AdultsObjective: The first three parts of the study revealed a strong correlation between sarcopenia biomarkers and cognitive impairment,and a common biomarker between sarcopenia and cognitive impairment.This study proposes to conduct a cross-sectional analysis using data from the 2015 China Health and Aging Tracking Survey(CHARLS)to assess the association between sarcopenic status and cognitive function in Chinese older adults.Methods: We included 2391 participants(35.63% female)who were at least 60 years of age in 2015 from the China Health and Retirement Longitudinal Study(CHARLS).Muscle strength,and physical performance measurements,were measured to diagnose possible sarcopenia according to the Asian Working Group 2019(AWGS2019).Cognitive function was assessed by 10 items in the Telephone Interview for Cognitive Status(TICS-10),delayed word recall,and graph drawing.Based on cognitive score tertiles,data were divided into three groups.Multiple linear and multi-classification logistic regression models were used to assess the relationship between sarcopenia and cognition.Results: The prevalence of possible sarcopenia was 27.16% for men and27.46% for women.Cognitive decline was significantly associated with sarcopenia status(β =-0.88,P < 0.001)and negatively associated with components of sarcopenia in male group.The results remained consistent in male after further adjusting for creatinine,uric acid,blood sugar,etc.In women only low muscle strength is associated with cognitive decline(β=-0.85,P = 0.02).In addition,participants with possible sarcopenia had greater risk of cognitive decline than those without sarcopenia(OR = 1.41;95%CI:1.06-1.87).However,the same association was not significant in female group.Conclusions: In Chinese population,sarcopenia may be significantly associated with risk of cognitive decline. |
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