The Study On Abnormal Postprandial Triglyceride Metabolism In Essential Hypertension

Objective To explore whether patients with essential hypertension (EH) are companied with insulin resistance and postprandial abnormal metabolism of serum triglyceride-rich lipoprotein (TGRL) and to investigate the relationship between the abnormality of postprandial triglyceride metabolism and insulin resistance, the variance at codon 54 of fatty acid-binding protein 2 gene (FABP2). Methods In 50 patients with essential hypertension and 30 healthy control subjects(NS), triglyceride, high-density lipoprotein cholesterol, total cholesterol, apolipoprotein AI, apolipoprotein B, glucose before and 2, 4, 6, 8 hours after a standardized fat loading. Triglyceride peak response (TGPR) and the area under triglyceride curve (TG-AUC) over 8 hours were regarded as the index of the TG response level of the fat loading. Standardized 75g oral glocuse tolerance test was carried , the area under insulin curve(IS-AUC) over 3 hours and insulin sensitivity index (ISI) were taken as the index of insulin sensitivity. Using polymerase chain reaction (PCR), the variants of IFBP2 gene were screened with the restrict fragment length polymorphism (RFLP) analysis.Results (1) TGPR and TG-AUC were higher in EH than those in NS(TG-AUC: 19.98 6.48 vs 9.95 3.67mmol/L, TGRP: 4.14 2.96 vs 2.06 1.32 mmol/L, P<0.01). 65.9% of EH had abnormal postprandial serum triglyceride metabolism. (2) IS-AUC was higher in EH than that in NS, and ISI was lower in EH than that in NS. The incidence of IR in EH was 62%. (3) 50 EH were categorized into 2 subgroups according to insulin sensitivity: EH with IR(n=31) and EH with normal insulin sensitivity(NIS,n=19). TGPR and TG-AUC in EH with IR were significantly higher than those in EH with NIS(TGPR: 5.25 3.03 vs 3.16 1.46 mmol/L,P<0.05; TG-AUC: 25.23 12.59 vs 12.98 7.12 mmol/L, P<0.01),but no significant difference was found between EH with NIS and NS (P>0.05). (4) Multivariateanalysis showed TG-AUC and TRPG was positively related to IS-AUC, fasting TG, DBP, body mass index(BMI), waist circumference and negatively related to ISI. ISI was the strongest impact factor on TG-AUC and TGPR. (5) The frequencies of threonine-encoding allele (Thr54) had no difference between EH and NS (0.28 vs 0.25, P>0.05). Thr54 homozygotes and Thr54 heterozygotes had higher TG-AUC and TGPR than wild-type (Ala54 homozygotes) in EH (TG-AUC: 28.2 6. 11, 21.9 6. 16 vs 13.9 6. 07 mmol/L, P<0. 05; TGPR: 7.56 2. 67, 4. 20 1. 62 vs 2. 34 1. 47 mmol/L, P<0. 05). Thr54 homozygotes had significantly higher TG-AUC and TGPR than Thr54 heterozygotes(P<0. 05).Conclusion 1. patients with EH had postprandial abnormal triglyceride metabolism, insulin resistance may aggravate postprandial triglyceride metabolism in EH. 2. FABP2 threonine-encoding allele was associated with abnormal postprandial triglyceride metabolism.