Peripheral Blood Mitochondrial DNA Content Is Related to Insulin Sensitivity in Offspring of Type 2 Diabetic Patients
- Jihyun Song, PhD1,
- Jee Young Oh, MD2,
- Yeon-Ah Sung, MD3,
- Youngmi Kim Pak, PhD1,
- Kyong Soo Park, MD2 and
- Hong Kyu Lee, MD2
- 1Department of Biomedical Sciences, Korean National Institute Health
- 2Department of Internal Medicine and Institute of Endocrinology, Nutrition and Metabolism, Medical Research Center, Seoul National University
- 3Department of Internal Medicine, Ewha Womans University College of Medicine, Seoul, Korea
Abstract
OBJECTIVE—To investigate whether the peripheral blood mtDNA (pb-mtDNA) content is decreased and linked to insulin resistance in the offspring of type 2 diabetic patients.
RESEARCH DESIGN AND METHODS—A total of 82 offspring of type 2 diabetic patients and 52 age-, sex-, and BMI-matched normal subjects from the Mokdong, Korea, population were selected for this study by stratified, randomized sampling. Of the offspring of diabetic patients, 52 had normal glucose tolerance (NGT), 21 had impaired glucose tolerance (IGT), and 9 had newly diagnosed type 2 diabetes. The pb-mtDNA content was measured by real-time polymerase chain reaction with a mitochondria-specific fluorescent probe, normalized by a nuclear DNA, 28S rRNA gene. The associations between pb-mtDNA content and several parameters of insulin resistance were studied.
RESULTS—The pb-mtDNA contents tended to be lower in the 82 offspring of type 2 diabetic patients (1,084.7 ± 62.6 vs. 1,304.0 ± 99.2 in the offspring and control subjects, respectively, P = 0.051) and was significantly lower in the combined NGT and IGT offspring group (NGT+IGT, 1,068.0 ± 67.8, P < 0.05) than in the control subjects. In NGT+IGT offspring, the pb-mtDNA content was significantly correlated with logarithmically transformed insulin sensitivity (r = 0.253, P < 0.05) and was the main predictor of insulin sensitivity.
CONCLUSIONS—Quantitative mtDNA status might be a hereditary factor associated with type 2 diabetes and could serve as an indicator for insulin sensitivity.
- AIR, acute insulin response to glucose
- FAM, 5-carboxyfluorescein
- FSIGT, frequently sampled intravenous glucose tolerance test
- IGT, impaired glucose tolerance
- NGT, normal glucose tolerance
- pb-mtDNA, peripheral blood mtDNA
- PCR, polymerase chain reaction
- SG, glucose effectiveness
- SI, insulin sensitivity index
- TAMRA, 6-carboxy-tetramethyl-rhodamine
- Tfam, mitochondrial transcriptional factor A
Footnotes
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Address correspondence and reprint requests to Dr. Hong Kyu Lee, Department of Biomedical Sciences, Korean National Institute of Health, Eunpyung-Ku, Nokbun-Dong, #5, Seoul 122-701, Korea. E-mail: hkleemd{at}plaza.snu.ac.kr.
Received for publication 29 August 2000 and accepted in revised form 18 January 2001.
J.S. and J.Y.O. contributed equally to this work.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
