TY - JOUR
T1 - Successful versus failed adaptation to high-fat diet-induced insulin resistance
T2 - The role of IAPP-induced β-cell endoplasmic reticulum stress
AU - Matveyenko, Aleksey V.
AU - Gurlo, Tatyana
AU - Daval, Marie
AU - Butler, Alexandra E.
AU - Butler, Peter C.
PY - 2009/4
Y1 - 2009/4
N2 - OBJECTIVE-Obesity is a known risk factor for type 2 diabetes. However, most obese individuals do not develop diabetes because they adapt to insulin resistance by increasing β-cell mass and insulin secretion. Islet pathology in type 2 diabetes is characterized by β-cell loss, islet amyloid derived from islet amyloid polypeptide (IAPP), and increased β-cell apoptosis characterized by endoplasmic reticulum (ER) stress. We hypothesized that IAPP-induced ER stress distinguishes successful versus unsuccessful islet adaptation to insulin resistance. RESEARCH DESIGN AND METHODS-To address this, we fed wild-type (WT) and human IAPP transgenic (HIP) rats either 10 weeks of regular chow or a high-fat diet and prospectively examined the relations among β-cell mass and turnover, β-cell ER stress, insulin secretion, and insulin sensitivity. RESULTS-A high-fat diet led to comparable insulin resistance in WT and HIP rats. WT rats compensated with increased insulin secretion and β-cell mass. In HIP rats, in contrast, neither β-cell function nor mass compensated for the increased insulin demand, leading to diabetes. The failure to increase β-cell mass in HIP rats was the result of ER stress-induced β-cell apoptosis that increased in proportion to diet-induced insulin resistance. CONCLUSIONS-IAPP-induced ER stress distinguishes the successful versus unsuccessful islet adaptation to a high-fat diet in rats. These studies are consistent with the hypothesis that IAPP oligomers contribute to increased β-cell apoptosis and β-cell failure in humans with type 2 diabetes.
AB - OBJECTIVE-Obesity is a known risk factor for type 2 diabetes. However, most obese individuals do not develop diabetes because they adapt to insulin resistance by increasing β-cell mass and insulin secretion. Islet pathology in type 2 diabetes is characterized by β-cell loss, islet amyloid derived from islet amyloid polypeptide (IAPP), and increased β-cell apoptosis characterized by endoplasmic reticulum (ER) stress. We hypothesized that IAPP-induced ER stress distinguishes successful versus unsuccessful islet adaptation to insulin resistance. RESEARCH DESIGN AND METHODS-To address this, we fed wild-type (WT) and human IAPP transgenic (HIP) rats either 10 weeks of regular chow or a high-fat diet and prospectively examined the relations among β-cell mass and turnover, β-cell ER stress, insulin secretion, and insulin sensitivity. RESULTS-A high-fat diet led to comparable insulin resistance in WT and HIP rats. WT rats compensated with increased insulin secretion and β-cell mass. In HIP rats, in contrast, neither β-cell function nor mass compensated for the increased insulin demand, leading to diabetes. The failure to increase β-cell mass in HIP rats was the result of ER stress-induced β-cell apoptosis that increased in proportion to diet-induced insulin resistance. CONCLUSIONS-IAPP-induced ER stress distinguishes the successful versus unsuccessful islet adaptation to a high-fat diet in rats. These studies are consistent with the hypothesis that IAPP oligomers contribute to increased β-cell apoptosis and β-cell failure in humans with type 2 diabetes.
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U2 - 10.2337/db08-1464
DO - 10.2337/db08-1464
M3 - Article
C2 - 19151199
AN - SCOPUS:64649101777
SN - 0012-1797
VL - 58
SP - 906
EP - 916
JO - Diabetes
JF - Diabetes
IS - 4
ER -