著者

Yukio IKEDA Tadashi SUEHIRO Shigeo YAMANAKA Yoshitaka KUMON Hiroshi TAKATA Shojiro INADA Naoko OGAMI Fumiaki OSAKI Mari INOUE Kaoru ARII Kozo HASHIMOTO

出版者

The Japan Endocrine Society

雑誌

Endocrine Journal (ISSN:09188959)

巻号頁・発行日

vol.53, no.5, pp.665-670, 2006 (Released:2006-10-31)

参考文献数

23

被引用文献数

6 10

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The oxidative modification of low-density lipoproteins (LDL) plays a central role in the initiation and acceleration of atherosclerosis. Iron plays a part in the formation of highly toxic free radicals such as hydroxide and superoxide anions, which can induce lipid peroxidation. We investigated whether serum iron status was associated with circulating oxidized LDL (oxLDL) levels in type 2 diabetic patients, in whom oxidative stress and susceptibility to lipid oxidation were supposedly increased. Serum ferritin levels were significantly correlated with plasma oxLDL concentrations in both male and female patients (p<0.02 and p<0.05, respectively). No correlation was detected between ferritin and LDL-cholesterol (LDL-C) concentrations despite the close correlation between LDL-C and oxLDL concentrations (p<0.0001). Stepwise regression analysis showed that ferritin concentration was an independent positive determinant of oxLDL level, in addition to triglyceride concentration, body mass index and sex. This is the first report to show that serum ferritin is associated with circulating oxLDL levels in patients with type 2 diabetes. Further work is required to establish a causative link between iron excess and the development of diabetic vascular complications.

著者

YUKIO IKEDA TADASHI SUEHIRO TOSHIHIRO NAKAMURA YOSHITAKA KUMON KOZO HASHIMOTO

出版者

The Japan Endocrine Society

雑誌

Endocrine Journal (ISSN:09188959)

巻号頁・発行日

vol.48, no.1, pp.81-86, 2001 (Released:2006-11-25)

参考文献数

12

被引用文献数

91 94

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To examine the clinical significance of the insulin resistance index as determined by homeostasis model assessment (HOMA-IR), we investigated the relationship between HOMA-IR and the insulin resistance estimated by the euglycemic-hyperinsulinemic clamp method in various subgroups and compared the significance of HOMA-IR with that of fasting plasma insulin levels (FIRI). HOMA-IR was significantly correlated to the inverse of the glucose infusion rate (1/GIR) in both diabetic and non-diabetic subjects (r=0.747, P<0.0001 and r=0.419, P<0.002, respectively). In the diabetic patients, treatment with sulfonylureas did not weaken this correlation (r=0.833, P<0.0001). HOMA-IR was found to be closely related to FIRI (r=0.932, P<0.0001), but HOMA-IR was more closely associated with 1/GIR than FIRI was. HOMA-IR as well as 1/GIR was correlated with the visceral fat area (VFA) more closely than with the subcutaneous fat area (SFA), while FIRI was correlated almost equally with both of them. In conclusion, HOMA-IR is a convenient and beneficial method for evaluating insulin resistance, especially in subjects with visceral fat accumulation, and reflects insulin resistance obtained by euglycemic clamp more accurately than FIRI alone.