title: Mitochondrial disorder, diabetes mellitus, and findings in three muscles, including the heart.
abstract: The authors describe the case of a 50-year-old man with chronic progressive external ophthalmoplegia (CPEO), diabetes mellitus (DM), and coronary artery disease. The patient had no cardiac conduction abnormalities. During coronary artery bypass surgery, his heart and two skeletal muscles were biopsied. All three muscles showed ragged red fibers. The heart muscle showed significant glycogen accumulation. Analysis of mitochondrial DNA (mtDNA) showed a 5019-base-pair deletion, with no duplications. There were morphologically abnormal mitochondria in all 3 muscles, with clinically apparent difference in preservation of function. The combination of diabetes mellitus and mtDNA deletion is fortuitous, as they can be causally linked. The cardiac pathology allows speculation about the possible adaptive processes that may occur in the heart in DM. There are few reported cases with CPEO and excess glycogen in the heart. Most show deposition of fat and poorer clinical outcomes as compared to those with glycogen deposition. This observation may lend support to the hypothesis that in the myocardium, adaptive responses are mediated via changes in glucose handling, whereas alterations in fat metabolism likely represent maladaptation.
authors.affiliation: National Heart Institute, Kuala Lumpur, Malaysia. Modushudan.Bhattacharjee@uth.tmc.edu
authors.forename: M
authors.initials: M
authors.lastname: Bhattacharjee
authors.forename: B
authors.initials: B
authors.lastname: Venugopal
authors.forename: K T
authors.initials: KT
authors.lastname: Wong
authors.forename: Y-I
authors.initials: YI
authors.lastname: Goto
authors.forename: M B
authors.initials: MB
authors.lastname: Bhattacharjee
mesh_terms: D001706:Biopsy; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000150:complications* / Q000601:surgery; D004272:DNA, Mitochondrial / Q000235:genetics; D048909:Diabetes Complications / Q000473:pathology; D003924:Diabetes Mellitus, Type 2 / Q000473:pathology*; D017353:Gene Deletion; D006003:Glycogen / Q000648:ultrastructure; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D008929:Mitochondria, Heart / Q000648:ultrastructure; D008931:Mitochondria, Muscle / Q000648:ultrastructure; D017237:Mitochondrial Encephalomyopathies / Q000150:complications*; D018482:Muscle, Skeletal / Q000648:ultrastructure*; D009206:Myocardium / Q000648:ultrastructure*; D017246:Ophthalmoplegia, Chronic Progressive External / Q000150:complications* / Q000473:pathology
chemical_list: D004272:DNA, Mitochondrial; D006003:Glycogen