摘要Objective:The aim of this study was to investigate the prevalence of sarcopenia(SP)and its relationship with gut microbiota alterations in patients with hematological diseases before and after hematopoietic stem cell transplantation(HSCT).Methods:A total of 108 patients with various hematological disorders were selected from Peking University People's Hospital.SP was screened and diagnosed based on the 2019 Asian Sarcopenia Diagnosis Strategy.Physical measurements and fecal samples were collected,and 16S rRNA gene sequencing was conducted.Alpha and beta diversity analyses were performed to evaluate gut microbiota composition and diversity.Results:After HSCT,significant decreases in calf circumference and body mass index(BMI)were observed,accompanied by a decline in physical function.Gut microbiota analyses revealed significant differences in the relative abundance of Enterococcus,Bacteroides,Blautia and Dorea species before and after HSCT(P＜0.05).Before HSCT,sarcopenic patients had lower Dorea levels and higher Phascolarctobacterium levels than non-sarcopenia patients(P＜0.01).After HSCT,no significant differences in species abundance were observed.Alpha diversity analysis showed significant differences in species diversity among the groups,with the highest diversity in the post-HSCT 90-day group and the lowest in the post-HSCT 30-day group.Beta diversity analysis revealed significant differences in species composition between pre-and post-HSCT time points but not between SP groups.Linear discriminant analysis effect size(LEfSe)identified Alistipes,Rikenellaceae,Alistipes putredinis,Prevotellaceae defectiva and Blautia coccoides as biomarkers for the pre-HSCT sarcopenia group.Functional predictions showed significant differences in anaerobic,biofilm-forming and oxidative stress-tolerant functions among the groups(P＜0.05).Conclusions:This study demonstrated a significant decline in physical function after HSCT and identified potential gut microbiota biomarkers and functional alterations associated with SP in patients with hematological disorders.Further research is needed to explore the underlying mechanisms and potential therapeutic targets.