laura Konings1
(1) Department of Internal Medicine, Center for Diabetes and Vascular Medicine, Franciscus Gasthuis and Vlietland, Rotterdam, Nederland.
Background:
The Fibroblast Growth Factor (FGF) system is a novel endocrinological system with an important role in multiple metabolic pathways, among others insulin and lipid metabolism. Most data of this system have been collected in the fasting situation. The non-fasting changes have been less well studied. We aimed to evaluate the postprandial changes in FGF-19 and FGF-21 in patients with type 2 diabetes mellitus (T2DM) in relation to cardiometabolic parameters.
Methods:
In this single centre study fourteen males with T2DM underwent an 8 hrs standardized oral fat loading test. Every 2 hrs FGF-19 and FGF-21 among other parameters in blood were collected. Low and high responders were identified using the area-under-the curve (AUC).
Results:
Fourteen males with a mean age of 64.6 ± 8.6 (x ± SD) years and BMI of 29.4 ± 3.9 kg/m² were included. Compared with fasting, the mean concentration of FGF-19 (109.2 ±126.3 pg/mL) increased gradually and was maximal at six hours. In contrast, FGF-21 showed the opposite effect and decreased by 32% compared to fasting (423.2±395.5 pg/mL), almost returning to baseline at later timepoints. Fasting FGF-21 was positively correlated with waist (r: 0.77; P=0.001) and BMI (r: 0.62; P=0.02) and was negatively correlated with fasting free fatty acids (FFAs). Postprandial FGF-19 and FGF-21 were not associated with glucagon or insulin levels. Patients with a low FGF-19 AUC had significantly lower plasma cholesterol (P=0.016), LDL-C (P=0.002), apoB (P=0.03). Patients with a low FGF-21 AUC had higher FFAs (P= 0.004).
Conclusion:
This study suggests that FGF-19 and FGF-21 tend to change postprandially, therefore assessment of these hormones should be done in fasting conditions. Interindividual postprandial responses are high, and determinants are now partly elucidated. FGF-19 may have detrimental effects on cardiovascular risk due to its associations with plasma cholesterol levels. This can be explained by FGF-19 effects on bile acid metabolism. Higher FGF-21 levels may be due to resistance to the hormone closely linked to obesity.