Improving angiogenesis ameliorates the efficacy of ASO-based exon skipping for the treatment of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a severe X-linked disease caused by pathogenic variants in the <i>DMD</i> gene, resulting in the absence of functional dystrophin. Antisense oligonucleotide (ASO)-based therapies aim to restore the open reading frame and produce a truncated but functional dystrophin protein. Although several ASOs are approved in the United States and Japan via accelerated approval procedures, dystrophin restoration in patient biopsies remains low, underlining the need to improve ASO potency. One major limitation is poor ASO biodistribution to skeletal muscle, influenced by both ASO chemistry and pathological features of dystrophic tissue. In DMD patients and <i>mdx</i> mice, microvascular abnormalities and impaired angiogenesis likely restrict ASO delivery. Here, we hypothesized that enhancing muscle vascularization could improve ASO biodistribution and therapeutic outcomes. <i>Mdx</i> mice were treated with a pro-angiogenic treatment prior to ASO administration targeting exon 23 of dystrophin pre-mRNA. Angiogenic stimulation increased capillary density and improved ASO delivery to muscles (3.8-fold), exon skipping (1.8-fold), and dystrophin expression (1.5-fold) compared to ASO alone. These molecular improvements were associated with increased myofiber size, larger mean cross-sectional area, and decreased serum myomesin levels, without signs of toxicity. This study provides proof of concept that promoting angiogenesis can enhance the potency of ASO-based treatments, offering a complementary strategy to improve therapeutic outcomes in DMD.