Sex Differences In The Skeletal Muscle Transcriptome And Proteome Of Chronic Limb Threatening Ischemia Patients

Treatment options for chronic limb threatening ischemia (CLTI), the most severe clinical presentation of peripheral artery disease, are limited. Innovation in therapeutic design for these patients is hindered by two critical issues: 1) limited information on the mechanisms underlying tissue pathology specifically in this population, and 2) complications in understanding this information in the presence of other significant co-morbidities and individual patient characteristics. In this study, we sought the effects of patient sex on the transcriptomic and proteomic profiles of ischemic muscle in patients with CLTI. We hypothesized that biological sex would alter expression patterns in the CLTI limb muscle. Comparing the tissue transcriptomes of CLTI patients ( p <0.05 and > 1.5FC) revealed 456 differences (342 up- and 114 down-regulated genes). Interestingly, general decreases in gene ontology (GO) categories for extracellular matrix (ADAMTS4, ALPL, MMP9), response to hypoxia (SOCS3, STC1, THBS1), and regulation of angiogenesis (CHI3L1, SERPINE1) occurred in female CLTI patients. Sex-based comparisons of the limb tissue proteome ( p <0.05 and > 0.5Log 2 FC) identified 50 protein targets (38 increased and 12 decreased female/male), including: NDUFA3, PYGB, SOD3, SLC25A6, PLIN3, CAMK2B, MYH3, and SERPIND1. Segregation of tissue proteomes to the mitochondria (MitoCarta) identified 11 mitochondrial protein targets (9 increased and 2 decreased F/M), including: NDUFA12, NDUFA3, SLC25A6, ARF5, ECI2, PTGES2, and RTN4IP1. Despite an overall rightward shift in mitochondrial protein in female limb muscle, no differences were observed in mitochondrial content via citrate synthase or after proteome mitochondrial enrichment factor analysis. Additionally, no sex-based differences were observed in mitochondrial oxygen consumption across multiple substrates and platforms. In conclusion, general transcriptome and proteomic profiles of CLTI patients follow similar bioenergetic/mitochondrial profiles which are mirrored by similar functional changes that support the mitochondria as a sex-independent organelle for therapeutic design.