Fatty Liver Linked to Insulin Resistance in Obese Teens
Adolescents in study had similar visceral and muscle fat, either high or low hepatic fat fraction
WEDNESDAY, Sept. 1 (HealthDay News) -- In obese adolescents, fatty liver -- independent of visceral fat and intramyocellular lipid content (IMCL) -- is associated with impaired insulin activity in the muscles and liver; along with other findings, this suggests the liver plays a key role in insulin resistance in these individuals, according to research published in the August issue of Diabetes Care.
Ebe D'Adamo, M.D., of the Yale University School of Medicine in New Haven, Conn., and colleagues analyzed data from 43 obese adolescents. The participants, who had similar distribution of visceral and muscle fat, were divided into a group with a high hepatic fat fraction (HFF; above 5.5 percent) and a group with low HFF (below 5.5 percent). The adolescents underwent oral glucose tolerance testing and a two-step hyperinsulinemic-euglycemic clamp.
The researchers found that the high HFF group had lower whole-body insulin sensitivity index and estimates of insulin secretion. During low-dose insulin, the high HFF group had lower suppression of endogenous glucose production, with no difference seen during the second step. During the second step, this group also had lower glucose disposal rate. The researchers concluded that fatty liver plays an important role in obese adolescents' insulin-resistant state, regardless of visceral fat and IMCL.
"In summary, by accounting for visceral fat and IMCL, intrahepatic fat accumulation is more than a simple marker of insulin resistance in obese adolescents, being associated with impaired insulin sensitivity at the level of the liver, muscle, and adipose tissue," the authors write.