BACKGROUND: Chronic kidney disease (CKD) has emerged as a significant risk factor that accelerates atherosclerosis, decreases muscle function, and increases the risk of amputation or death in patients with peripheral artery disease (PAD). However, the modulators underlying this exacerbated pathobiology are ill-defined. Recent work has demonstrated that uremic toxins are associated with limb amputation in PAD and have pathological effects in both the limb muscle and vasculature. Herein, we utilize multiomics to identify novel modulators of disease pathobiology in patients with PAD and CKD. METHODS: A cross-sectional study enrolled four groups of participants: controls without PAD or CKD (n=28), patients with PAD only (n=46), patients with CKD only (n=31), and patients with both PAD and CKD (n=18). Both targeted (uremic toxins) and non-targeted metabolomics in plasma were performed using mass spectrometry. Calf muscle biopsies were used to measure histopathology, perform bulk and single-nucleus RNA sequencing (snRNAseq), and assess mitochondrial function. Differential gene and metabolite analyses, as well as pathway and gene set enrichment analyses were performed. RESULTS: Patients with both PAD and CKD exhibited significantly lower calf muscle strength and smaller muscle fiber areas compared to controls and those with only PAD. Compared to controls, mitochondrial function was impaired in CKD patients, with or without PAD, but not in PAD patients without CKD. Plasma metabolomics revealed substantial alterations in the metabolome of patients with CKD, with significant correlations observed between uremic toxins (e.g., kynurenine, indoxyl sulfate) and both muscle strength and mitochondrial function. RNA sequencing analyses identified downregulation of mitochondrial genes and pathways associated with protein translation in patients with both PAD and CKD. Single nucleus RNA sequencing further highlighted a mitochondrial deficiency in muscle fibers along with unique remodeling of fibro-adipogenic progenitor cells in patients with both PAD and CKD, with an increase in adipogenic cell populations. CONCLUSIONS: CKD significantly exacerbates ischemic muscle pathology in PAD, as evidenced by diminished muscle strength, reduced mitochondrial function, and altered transcriptome profiles. The correlation between uremic toxins and muscle dysfunction suggests that targeting these metabolites may offer therapeutic potential for improving muscle health in PAD patients with CKD.

The authors have declared no competing interest.

This was not a clinical trial.

This study was supported by National Institutes of Health (NIH) grants R01-HL149704 and HL171050 (T.E.R.). S.T.S. was supported by NIH grant R01HL148597. S.A.B. was supported by NIH grant R01DK119274. K.K. was supported by the American Heart Association grant POST903198. T.T. was supported by NIH grant F31-DK128920. V.R.P. was supported by the American Heart Association grant 24PRE1193999. C.P. was supported by the American Heart Association grant 24PRE1196311.

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This study was approved by the institutional review boards at the University of Florida and the Malcom Randall VA Medical Center (Protocol IRB201801553).

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