Association between triglycerides and remnant cholesterol levels and spine bone mineral density in Duchenne muscular dystrophy.

Background: Duchenne muscular dystrophy (DMD) is a serious, progressive neuromuscular condition that predominantly impacts male individuals, marked by progressive muscle weakness resulting from mutations in the dystrophin gene (DMD) encoding dystrophin. DMD is a primary muscle disorder that often presents with secondary abnormalities in lipid metabolism and decreased bone mineral density. Although disturbances in circulating lipid profiles and skeletal health have been observed in individuals with DMD, their relationship remains underexplored.This study aimed to investigate the potential association between lipid metabolic disturbances and spinal bone mineral density in patients with DMD by combining clinical lipid levels and bone density with transcriptomic pathway analysis of DMD muscle tissue.

Methods: Retrospective analysis was performed on 219 genetically confirmed DMD patients and 99 age-matched healthy controls. Healthy controls with a family history of genetic disorders were excluded. Clinical data included lipid profiles (triglycerides [TGs], remnant cholesterol [RC]); bone mineral density of the lumbar spine was evaluated using Dual-energy X-ray absorptiometry (DXA); and corticosteroid use, including treatment status, dose, and duration. Patients were stratified by corticosteroid exposure. Restricted cubic splines and multivariable regression models were applied to explore potential relationships between lipid parameters and bone mineral density. Bioinformatic analyses were performed on RNA sequencing data from muscle biopsy samples from patients with DMD (GSE38417 dataset) and an independent validation cohort (GSE6011 dataset), focusing on pathways related to lipid metabolism and osteoclast differentiation.

Results: Patients with DMD had higher TG, RC, and apolipoprotein B (ApoB) levels and lower high-density lipoprotein cholesterol (HDL-C) levels than healthy controls (P < 0.05). Elevated TG and RC levels were associated with reduced spine bone mineral density, independent of corticosteroid use. The bioinformatic analyses identified key pathways, including sphingolipid metabolism and osteoclast differentiation, as well as hub genes such as FCGR2B, C1QA, which are involved in lipid regulation and bone remodeling.

Conclusions: Lipid abnormalities, particularly elevated TG and RC levels, were significantly associated with lower bone mineral density in patients with DMD. These findings suggest that lipid abnormalities are involved in bone health impairment in DMD, warranting further studies to confirm the association.