Myoblast-seeded alginate tubes exacerbate dystrophic features in a mouse model of dysferlinopathy

Introduction: Physical therapy (PT) alone is insufficient to restore lost skeletal muscle tissue in individuals with genetic muscle diseases, such as limb-girdle muscular dystrophy type 2B (LGMD2B). However, PT delivered within a regenerative rehabilitation framework -- one that combines cellular therapies with movement-based interventions has the potential to change the status quo in the field. Therefore, we developed a novel muscle regeneration strategy, which could be augmented by targeted, dosage-adjusted progressive resistance training. This study examined if alginate tubes containing myogenic cells could support in vivo muscle regeneration in a mouse model of LGMD2B. Methods: The technology to generate and implant myogenic alginate tubes was first developed and validated through in vitro experimentation. Using this workflow, we produced 21-gauge alginate tubes composed of 10% sodium alginate and healthy donor myogenic cells. Our laboratory has previously developed a technique known as minimally-invasive muscle embedding (MIME), which is effective in generating donor-cell-derived myogenesis in the mouse tibialis anterior (TA) muscle. In this study, we implanted cellularized alginate tubes into the left TA muscle of four female mice from a mouse model of LGMD2B (dysferlin-deficient) using MIME. Histological evaluation was performed 28 days post-implantation. No statistical analyses were performed due to the exploratory nature and small sample size. Results: Cellularized alginate tubes did not dissolve within host muscle even 28 days post-implantation – we had predicted that the alginate tubes would dissolve within a few days. Furthermore, there was no evidence of donor-cell-derived myogenesis. Unexpectedly, we found that MIME-treated muscles exhibited aggravated dystrophic features, including increased fibrosis, lipid deposition, and muscle fiber size heterogeneity, relative to contralateral control limbs. Discussion: The persistence of alginate constructs and absence of donor myogenesis suggest that delivery systems requiring faster degradation or better host-cell integration may be needed. Despite the unexpected outcome, the model revealed a more severe phenotype than typical LGMD2B mice, offering potential utility in future preclinical testing. Conclusions: Engineered myogenic constructs using alginate tubes failed to promote donor-cell-derived regeneration but may enhance modeling of LGMD2B for basic and preclinical studies. Improvements in construct design and additional testing in healthy and dystrophic mice are warranted. Acknowledgments: Supported by NIH R03HD091648, NIH P2CHD086843 (AR3T Pitch Award), NIH R01AR079884 (subcontract), Wayne State Warrior Funder, and the Jain Foundation. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.