Hepatic iron stores are increased as assessed by magnetic resonance imaging in a Chinese population with altered glucose homeostasis

Abstract

Background: Emerging scientific evidence has disclosed a correlation between iron metabolism and type 2 diabetes (T2D). Objective: The objective of this study was to test the hypothesis that body iron stores are higher in a Chinese population with altered glucose homeostasis. Design: Serum iron, ferritin, and soluble transferrin receptor concentrations were measured in 298 subjects, including 70 subjects with normal glucose tolerance (NGT group), 60 subjects with prediabetes (prediabetes group), and 168 subjects with T2D (T2D group). Hepatic iron stores in 88 subjects were assessed by using a magnetic resonance imaging (MRI) T2* gradient-recalled-echo technique. A general linear model ANOVA was performed for comparisons between groups after adjustment for age and BMI.Stepwise multiple linear regression analysis was used to identify factors associated with the MRI-estimated hepatic iron concentration (M-HIC). Results: Mean (6SD) M-HIC and R2* values in the prediabetes and T2D groups were significantly higher than in the NGT group (M-HIC: 40.6 6 8.6 and 39.3 6 10.7 lmol/g compared with 27.8 6 9.1 lmol/g; R2* values: 47.9 6 11.9 and 47.3 6 11.5 s 21 compared with 34.9 6 7.0 s 21; all P , 0.01). No significant difference was shown in M-HIC and R2* values between prediabetes and T2D groups. The M-HIC independently contributed to 43.3% of the glycated hemoglobin variance after adjustment for main clinical indexes (P , 0.001). The proportions of subjects with mild hepatic iron overload in the NGT, prediabetes, and T2D groups were 12.5%, 70.6%, and 63.6%, respectively. Conclusions: To our knowledge, our findings provide novel evidence to support the hypothesis of a mild iron overload in patients with prediabetes and T2D. A cohort study concerned with the effect of the attenuation of excess iron on glucose metabolism in a prediabetic population is warranted.Am J Clin Nutr 2011;94:1012-9.

Hepcidin Is Directly Regulated by Insulin and Plays an Important Role in Iron Overload in Streptozotocin-Induced Diabetic Rats

“…However, no significant change in Hb was observed in the current study. Clinical studies (2,17) also reported that Hb remained unchanged in DM2 or IGT patients. In addition, hyperglycemia may be also involved in hepcidin regulation.…”

“…In conclusion, the current study suggests that hepcidin can be directly regulated by insulin, and the suppressed liver hepcidin synthesis may be an important reason for the iron overload in DM2. Body iron overload is frequently observed in patients with type 2 diabetes mellitus (DM2) (1,2) or impaired glucose tolerance (IGT) (3,4). Iron overload has been confirmed as an independent factor contributing to the development of DM2 by causing oxidative stress injury in hepatocytes and pancreatic b-cells (5), which may finally lead to insulin resistance (IR) and reduction in insulin extraction and secretion (6).…”

Insulin Resistance Modulates Iron-Related Proteins in Adipose Tissue

“…Until now, only tissue iron in the liver has been identified to be associated with systemic insulin action (43,44). AT iron should be evaluated in association with the expression of the different genes involved in iron metabolism.…”

Iron Overload Effect on Serum Levels of Glucose, Insulin and HOMA-IR was Ifluenced by the Type of Fat in Female Sprague-Dawley Rats Fed High-Fat-Diets

“…Iron overload in liver can disrupt insulin inhibition of hepatic glucose production, which together in conjunction with reduced hepatic extraction of insulin, leads to peripheral hyper-insulinemia [17]. Zheng and his colleagues [13] noticed that liver iron content was increased in people with T2DM and insulin resistance [14], similarly, Bao and colleagues concluded that increased body iron stores were significantly associated with the risk of T2DM [15].…”

“…Epidemiological studies showed an association between iron stores and the development of metabolic syndrome [13]. Zheng and colleagues [13] noted that liver iron is increased in people with T2DM and insulin resistance [14]. Moreover, increased body iron stores were significantly associated with risk of T2DM [15].…”