Identification of a novel immune-related transcriptional regulatory network in sarcopenia.

BACKGROUND: Sarcopenia is highly prevalent in elderly individuals and has a significant adverse effect on their physical health and quality of life, but the mechanisms remain unclear. Studies have indicated that transcription factors (TFs) and the immune microenvironment play a vital role in skeletal muscle atrophy. METHODS: RNA-seq data of 40 muscle samples were downloaded from the GEO database. Then, differentially expressed genes (DEGs), TFs(DETFs), pathways(DEPs), and the expression of immune gene sets were identified with limma, edgeR, GO, KEGG, ORA, GSVA, and ssGSEA. Furthermore, the results above were integrated into coexpression analysis by Pearson correlation analysis (PCA). Significant coexpression patterns were used to construct the immune-related transcriptional regulatory network by Cytoscape and potential medicine targeting the network was screened by Connectivity Map. Finally, the regulatory mechanisms and RNA expression of DEGs and DETFs were identified by multiple online databases and RT‒qPCR. RESULTS: We screened 808 DEGs (log2 fold change (FC) > 1 or < - 1, p < 0.05), 4 DETFs (log2FC > 0.7 or < - 0.7, p < 0.05), 304 DEPs (enrichment scores (ES) > 1 or < - 1, p < 0.05), and 1208 differentially expressed immune genes sets (DEIGSs) (p < 0.01). Based on the results of PCA (correlation coefficient (CC) > 0.4 or < - 0.4, p < 0.01), we then structured an immune-related network with 4 DETFs, 9 final DEGs, 11 final DEPs, and 6 final DEIGSs. Combining the results of online databases and in vitro experiments, we found that PAX5-SERPINA5-PI3K/Akt (CC ≤ 0.444, p ≤ 0.004) was a potential transcriptional regulation axis, and B cells (R = 0.437, p = 0.005) may play a vital role in this signal transduction. Finally, the compound of trichostatin A (enrichment = -0.365, specificity = 0.4257, p < 0.0001) might be a potential medicine for sarcopenia based on the PubChem database and the result of the literature review. CONCLUSIONS: We first identified immune-related transcriptional regulatory network with high-throughput RNA-seq data in sarcopenia. We hypothesized that PAX5-SERPIAN5-PI3K/Akt axis is a potential mechanism in sarcopenia and that B cells may play a vital role in this signal transduction. In addition, trichostatin A might be a potential medicine for sarcopenia.

Impact of sarcopenia on clinical outcomes of patients with stage I gastric cancer after radical gastrectomy: A prospective cohort study.

BACKGROUND: The relationships between sarcopenia and postoperative outcomes in patients with early-stage gastric cancer who undergo radical gastrectomy is unclear. We aimed to investigate the predictive value of sarcopenia on adverse outcomes for stage I gastric cancer. METHODS: The clinical data of patients who underwent radical gastrectomy for stage I gastric cancer between July 2013 and May 2019 were prospectively collected. Basic sarcopenia components were measured preoperatively. Univariate and multivariate analyses were conducted to evaluate the risk factors for short- and long-term outcomes. RESULTS: A total of 507 patients with early-stage gastric cancer were included in the study, and 73 (14.4%) patients were diagnosed as sarcopenia. Patients with sarcopenia had significantly higher incidence of postoperative complications (32.9% vs. 17.5%, P = 0.002), longer postoperative hospital stays (13 days vs. 12 days, P < 0.001), higher hospitalization costs (65210 yuan vs. 55197 yuan, P < 0.001) and one-year mortality (8.2% vs. 1.8%, P = 0.002). During the median follow-up time of 38.8 months, 12 (16.4%) patients dead in the sarcopenic group and 25 (5.8%) patients dead in the non-sarcopenic group. Sarcopenia was an independent risk factor for both short- and long-term clinical outcomes. Moreover, we found that low muscle quantity and low handgrip strength mediated the adverse impacts of sarcopenia on postoperative complications while low muscle quality mediated the adverse impacts of sarcopenia on overall survival. CONCLUSION: Sarcopenia was strongly associated with worse short- and long-term clinical outcomes in patients with stage I gastric cancer who undergo radical gastrectomy.