THE EFFECTS OF COENZYME Q(10) TREATMENT ON MATERNALLY INHERITED DIABETES-MELLITUS AND DEAFNESS, AND MITOCHONDRIAL-DNA 3243 (A TO G) MUTATION

The characteristic clinical features of diabetes mellitus with mitocho ndrial DNA (mtDNA) 3243(A-G) mutation are progressive insulin secretor y defect, neurosensory deafness and maternal inheritance, referred to as maternally inherited diabetes mellitus and deafness (MIDD). A treat ment for MIDD to improve insulin secretory defects and reduce deafness has not been established. The effects of coenzyme Q(10) (CoQ(10)) tre atment on insulin secretory response, hearing capacity and clinical sy mptoms of MIDD were investigated. 28 MIDD patients (CoQ(10)-DM), 7 mut ant subjects with impaired glucose tolerance (IGT), and 15 mutant subj ects with normal glucose tolerance (NGT) were treated daily with oral administration of 150 mg of CoQ(10) for 3 years. Insulin secretory res ponse, blood lactate after exercise, hearing capacity and other labora tory examinations were investigated every year, In the same way we eva luated 16 MIDD patients (control-DM). 5 mutant IGT and 5 mutant NGT su bjects in yearly examinations. The insulin secretory response assessed by glucagon-induced C-peptide secretion and 24 h urinary C-peptide ex cretion after 3 years in the CoQ(10)-DM group was significantly higher than that in the control-DM group. CoQ(10) therapy prevented progress ive hearing loss and improved blood lactate after exercise in the MIDD patients. CoQ(10) treatment did not affect the diabetic complications or other clinical symptoms of MIDD patients. CoQ(10) treatment did no t affect the insulin secretory capacity of the mutant IGT and NGT subj ects. There were no side effects during therapy This is the first repo rt demonstrating the therapeutic usefulness of CoQ(10) on MIDD.