Hyperleptinaemia and its Association with Postprandial Hypertriglyceridemia and Glucose Intolerance

Leptin resistance is believed to cause insulin resistance though the exact mechanism is not fully understood. The present study aims to investigate the temporal profile of postprandial triglyceride (PPTG) and leptin levels, and their association with each other as well as with markers of metabolic syndrome.

Serum leptin and PPTG levels were measured longitudinally till 26 weeks in Wistar rats fed on controlled diet (group 1) and high sucrose diet (HSD) (group 2). Two additional groups fed on HSD were taken and treated with pioglitazone (group 3) and atorvastatin (group 4). Body weight, homeostasis model assessment of insulin resistance (HOMA-IR), and glucose intolerance were also measured during this period. Comparison of the groups were done and Pearson's correlation coefficient was used to ascertain the association.

Leptin levels were significantly higher in all three groups receiving HSD compared to controlled diet group from week 2 to week 26 (P < 0.01). The postprandial triglyceride area under the curve (PPTG AUCs) were significantly higher in group 2 than controls during this period (P < 0.001). Body weight, HOMA-IR and glucose AUC were found to be significantly higher in group 2 rats than controls only from week 6, 8, and 12 respectively. In HSD-fed rats, but not in control, mean serum leptin levels from 2-26 weeks as well as peak (10^th week) and 26^th week were strongly associated with corresponding as well as preceding PPTG levels. Leptin levels significantly predicted HOMA-IR and prediabetes in group 2.

This study found significant hyperleptinemia associated with postprandial hypertriglyceridemia that predicted insulin resistance and prediabetes in high sucrose diet-fed rats.