Differential Myopathic and Transcriptomic Changes in Soleus and Gastrocnemius Muscles in a Novel Chronic Hindlimb...

Peripheral artery disease (PAD) is a progressive atherothrombotic disorder affecting more than 230 million people worldwide. Conventional animal models of chronic hindlimb ischemia (HLI) are highly invasive, technically challenging, fail to account for anatomical variation, and may not accurately recapitulate progressive PAD pathophysiology. To address these limitations, we developed a novel chronic HLI model using an ilio-femoral endovascular catheter occlusion (IFCO) approach. We hypothesized that IFCO would chronically reduce hindlimb blood flow, induce PAD-associated myopathy, and overcome limitations of conventional techniques. Laser Doppler perfusion imaging demonstrated that IFCO reduced resting hindlimb perfusion by 70%, with significant reductions persisting for up to 28 days. Histological analysis of the soleus revealed significantly increased fibrosis (4.99% in sham vs. 13.19% in IFCO) and reduced myofiber cross-sectional area (3072.21 μm² in sham vs. 1556.27 μm² in IFCO), whereas no significant differences were observed in the gastrocnemius. In contrast, IFCO increased the proportion of centralized nuclei from near 0% in sham muscles to 21.55% in the gastrocnemius and 32.65% in the soleus. RNA sequencing corroborated these findings and demonstrated that the ischemic soleus transcriptome exhibited enhanced fibrotic, pro-angiogenic, and myoblast fusion-associated signaling consistent with histological evidence of myopathy. These findings demonstrate that IFCO produces sustained hindlimb ischemia and PAD-associated skeletal muscle remodeling, with distinct responses between muscle types. This model may facilitate studies of PAD-associated myopathy and support the development of targeted therapeutic interventions.