Adipose tissue insulin resistance linked to reduced free fatty acid suppression
During oral glucose tolerance testing, adipose tissue insulin resistance is associated with reduced suppression of free fatty acids in people with an altered adipocytokine profile.
Ram Weiss, MD, PhD, associate professor of human nutrition in the department of human metabolism and nutrition at Hebrew University in Jerusalem, and colleagues evaluated data from the Yale Pathophysiology of Type 2 Diabetes in Youth study on 962 children and adolescents with obesity to assess adipose tissue insulin resistance across glucose tolerance and to evaluate its relation with free fatty acid suppression during OGTT.
Participants were divided into groups based on glucose tolerance: normal glucose tolerance (n = 770), prediabetes (n = 170) and diabetes (n = 22).
Across the glucose tolerance categories, adipose insulin resistance increased significantly (P < .001 for trend). Compared with pubertal participants, prepubertal children had higher fasting free fatty acids (P = .001) and lower fasting insulin (P = .004) and adipose insulin resistance index (P = .03).
A subsample of 115 participants underwent abdominal MRI for determination of lipid partitioning, and researchers found a tight relation of visceral fat (P < .001) and visceral/total abdominal fat ratio (P < .001) with adipose insulin resistance index. However, the relation with abdominal subcutaneous fat was not significant.
Across glucose tolerance categories, the area under the curve (AUC) for free fatty acids was significantly lower (P < .001 for trend); the normal glucose tolerance group had greater free fatty acid suppression. A significant relationship was found between AUC free fatty acids and adipose insulin resistance index (P < .001). Predictors of adipose insulin resistance were identified as glucose tolerance category, BMI z score, interleukin-6 and low adiponectin.
“In this analysis, we show that the adipose [insulin resistance] index is greater in those with altered glucose metabolism, even within the normal glucose tolerance range,” the researchers wrote. “This index is associated with overall obesity as reflected by BMI z score, yet is also tightly linked to abdominal lipid partitioning. Moreover, this index is a strong determinant of [free fatty acid] suppression during the OGTT indicating its major involvement in glucose metabolism.” – by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.