The Relationship Between Lipid Metabolism Following A Mixed Meal And Macrovascular Complication In Type 2 Diabetic Patients

Objective: Diabetes mellitus (DM) is a common diseaseand its macrovascular complication whose pathology isatherogenesis (AS) becomes one of the reasons causing death.In recent years, many studies have showed abnormal lipidmetabolism related to insulin resistance (IR) may play aimportant role in macrovascular complication of type 2 DM.Fasting serum lipid was usually measured, but the most time ofmen is postprandial state, so the fasting serum lipid may notreflect exactly physiological condition. Some fastingnormalipemic type 2 diabetic patients have been found sufferingfrom micravascular complication. In our study, we measurepostprandial serum lipid following a mixed meal and activity ofthe key enzyme in the during of lipid metabolism, namedlipoprotein lipase (LPL), so that can futherly know therelationship between postprandial lipid metabolism and diabeticmacrovascular complication exactly. And we can give theroicalbasis for earlier diagnose and therapy of diabetic abnormal lipidmetabolism, and reduce diabetic complication.Method: Forty-five type 2 diabetic patients (1999 WHOdianostic standards) were selected for this study, whose durationwere within ten years, HbA1c>7%, without present acute andchronic inflammatory disease, indigestion. Subjects wereassigned to three groups: the observed group (A group) ofthirty-five fasing normalipemic type 2 diabetic patients(TG≤1.7mmol/L), 55.9±7.9 years old, twenty male and fifteenfemale, who were divided into two subgroups based onpostprandial four hours TG (TG4h), TG4h≤2.0mmol/L as A1group, and TG4h>2.0mmol/L as A2 group; the hyperlipemicgroup (B group) of ten fasing hyperlipemic type 2 diabeticpatients (TG>1.7mmol/L), 56.7±8.6 years old, five male andfive female. Sixteen healthy individuals were used as controlgroup, 52.3±7.8 years old, nine male and seven female, withoutacute and chronic inflammatory disease, history of DM, vasculsr,liver, kidney, hypertention and indigestion disease, with normalfasting and postprandial BG and serum lipid. The main clinicalfeatures such as TG, TC, HDL, LDL, activity of LPL, BG, INS,HbA1c, BP, BMI and WHR were measured in all subjects. Theserum lipid was measured by chemical method. The activity ofserum LPL was measured by colorimetric method.All the data were expressed as mean±SE. Statisticalcomparisons were done using independent-sample T test orone-way ANOVA. Relations of variables were described usinglinear correlation and multiple stepwise logistic regressiveanalyses. All the statistical analysis were dealt with SPSS 12.0software.Result: 1. 2-8h after a mixed meal, a postprandial increaseof serum TG was observed in control and A group. A group hadhigher levels of postprandial TG than control group, and therewas significant difference only at postprandial 4h (P<0.05). Agroup had higher levels of TG-AUC, TGPR and TGPT thancontrol group, which suggests the former had elevation anddelayed clearance of TG. 2. 2-8h after a mixed meal,postprandial increase of serum TG and activity of LPL wereobserved in control, A1, A2, B group. There was significantdifference of TG only between A1 and A2 group at postprandial4h (P<0.05). And following the above order (the level of TGgradually higher) the activity of LPL became gradually lower,and there was significant difference only between A1 and A2group at postprandial 4h (P<0.05). 3. In all type 2 diabeticpatients, there were negative correlation between activity ofserum LPL and TG (r=-0.463, P<0.01), between activity of LPLand ISI at 4h after a mixed meal (r=-0.429, P<0.01). There werepositive correlation between TG-AUC and ISI (r=0.332,P<0.05), between BMI and ISI (r=0.382, P<0.05). 4. Accordingto the order of A1, A2,B group (the level of TG gradually higher),the prevalence of diabetic macrovascular complication were21.6%,65.8%,72.1%, and there was significant differencebetween A1 and A2 group (P<0.05), but no significant differencebetween A2 and B group (P>0.05). 5. To define the independentvariables related to diabetic macrovascular complication, fifteenvariables were taken into the multiple stepwise logisticregressive analyses. The fifteen variables were age, during, BMI,WHR, HbA1c, INS, fasting and postprandial BG, ISI, fasting TG,TC, HDL, LDL, TG4h and activity of LPL4h. Both TG4h and BMIwere selected, TG4h: β=1.421, P=0.032, OR=4.143; BMI:β=0.533, P=0.012, OR=1.705. 6. Following the order of control,D₁ (macrovascular complication), D2 group (no macrovascularcomplication), fasting and postprandial serum TG of everygroup became gradually higher, and there was significantdifference between D₁ and D2 group at postprandial 2-8h(P<0.05).Conclusion: 1. In some of fasing normalipidemic type 2diabetic patients, 2-8h after a mixed meal, a significantpostprandial increase of serum TG was observed, and up to 8hthe level of TG was still higher than fasting. There weresignificant increase of TG-AUC, TGPR and TGPT betweensome of fasing normalipidemic type 2 diabetic patients andcontrol group. These suggest they had postprandial abnormallipid metabolism, which included elevation of TG, delayedclearance of TG. 2. Following the order of A1, A2, B group (thelevel of TG gradually higher), the prevalence of diabeticmacrovascular complication became gradually higher, and therewas significant difference between A1 and A2 group (P<0.05).Multiple stepwise logistic regressive analyses showed TG_4hindependently related with diabetic macrovascular complication.Following the order of control, D1 (macrovascular complication),D2 group (no macrovascular complication), fasting andpostprandial serum TG of every group became gradually higher,...