| Objective: The'lipotoxicity'theory has been recognized as an important factor of type 2 diabetes mellitus (T2DM). FFA prevalently increased in the patients of T2DM. FFA is came from TG (triglyceride), which is located in CM (chylomicyonscm) and VLDL (very low density lipoprotein) that decomposed by LPL (lipoprotein lipase). Someone has demonstrated that FA (fatty acid) is disordered in the patients of T2DM and high risk group people. Meanwhile, linoleic acid and arachidonic acid are more increased than the control group. Maybe they play an important role in DM. It is not clear that whether the free fatty acid composition and lipoprotein lipase is changed or not when plasma glucose fluctuate. My experiment studied the transmutation of the composition of free fatty acid and lipoprotein lipase in fasting and oral glucose after 2 hours by OGTT. It offered proof for the prevention and cure in lipid disorders of DM.Methods: Selected 65 patients with T2DM from department of endocrinology in the second hospital of Hebei medical univerity, of which 34 male and 31 female, 51.1±11.9 years old, and the average duration of diabetes 6.87±5.9 years. I recorded the basic message of patients, including name, sex, age, height, weight, blood pressure, duration, past history, diagnosis and some laboratory examination. All subjects were taken the oral glucose tolerance test (OGTT). According to the 1999 WHO diagnostic criteria for diabetes mellitus, they were diagnosed with T2DM. According to the difference of oral glucose after 2 hours and fasting plasma glucose, we divided all subjects into three groups: A group (difference <6mmol/l), B group (difference 6-10mmol/l), C group (difference >10mmol/l). We divided all subjects intoâ… group (HbA1c<7%),â…¡group (HbA1c 7-10%),â…¢group (HbA1c>10%) by HbA1c. We analyzed all the data in SPSS 13.0 software. Continuous variables with normal distributions are expressed as mean and standard deviation (X±S). The comparisons between groups used Student's t-test for independent samples and one-way analysis variance (ANOVA). The correlation analysis of each variable applied linear correlation.Results:1 Explore the impact of plasma glucose fluctuate immediately1.1 Comparison of OGTT fasting and after 2 hours'plasma glucose, blood lipid, TFA, FFA composition and LPL activityThe plasma glucose of OGTT after 2 hours was significantly higher than fasting (P<0.01). The TG concentration of OGTT after 2 hours was higher than fasting, and the HDL concentration was lower than fasting (P <0.05).The TC and LDL concentration did not change significantly (P>0.05). The TFA concentration of OGTT after 2 hours was lower than fasting (P<0.05). The C16: 0, C16: 1, C18: 1, C18: 2, C18: 3 concentration of OGTT after 2 hours were lower than fasting (P<0.05), and the others did not change obviously (P>0.05). The LPL activity of OGTT after 2 hours decreased significantly compared with fasting (P<0.01).1.2 Comparison of lipid, TFA, Homa-IR, FFA composition and LPL activity of fasting among the A, B, C groupsAmong the three groups, the lipid, TFA, all fatty acids and LPL activity of fasting were not changed obviously (P>0.05). With the increase of plasma glucose fluctuation, Homa-IR gradually increased, A group B group> C group, and the comparison between A group and C group was statistically significant (P <0.05).1.4 Comparison of FFA composition and LPL activity of OGTT after 2hours among the A, B, C groupsWith the increase of plasma glucose fluctuation, the comparison of C16: 0 between A and B group was statistically significant (P<0.05), A group> C group> B group. With the increase of plasma glucose fluctuation, the C16: 1, C18: 1, C18: 2, C18: 3 gradually reduced, A group> B group> C group, and the comparison between A and C group was statistically significant (P<0.05). With the increase of plasma glucose fluctuation, LPL activity decreased gradually, A group> B group> C group, and the comparison among the three groups was statistically significant (P<0.05).2 Explore the impact of long-term hyperglycemia2.1 Effect of long-term hyperglycemia on fasting lipid, fasting TFA and Homa-IRThe TG and LDL concentration increased gradually with the increase of HbA1c,â… group <â…¡group <â…¢group, and the comparison betweenâ… group andâ…¢group was statistically significant (P<0.05). The HDL concentration decreased gradually with the increase of HbA1c,â… group >â…¡group >â…¢group, and the comparison betweenâ… group andâ…¢group was statistically significant (P<0.05). The fasting TFA increased gradually with the increase of HbA1c,â… group <â…¡group <â…¢group, and the comparison among the three groups was statistically significant (P<0.05). The Homa-IR increased gradually with the increase of HbA1c,â… group <â…¡group <â…¢group, and the comparison among the three groups was statistically significant (P<0.05).2.2 Effect of long-term hyperglycemia on fasting FFA composition and LPL activityThe C16: 0, C18: 0, C22: 0 concentration increased gradually with the increase of HbA1c,â… group <â…¡group <â…¢group, and the comparison betweenâ… group andâ…¢group was statistically significant (P<0.05). The fasting LPL activity decreased gradually with the increase of HbA1c,â… group >â…¡group >â…¢group, and the comparison among the three groups was statistically significant (P<0.05).3 Correlation analyses3.1 Correlation analysis between blood lipid, TFA, FFA composition, LPL activity of fasting and Homa-IRThe TG, LDL and TFA of fasting were positively correlated with Homa-IR (P<0.05). The C16: 0, C18: 0, C22: 0 of fasting were positively correlated with Homa-IR (P<0.05). The fasting LPL activity was negatively correlated with Homa-IR (P<0.05).3.2 Correlation analysis between blood lipid, TFA, FFA composition, LPL activity of OGTT after 2 hours and Homa-IRThe TG, LDL and TFA of OGTT after 2 hours were positively correlated with Homa-IR (P<0.05). There were no significant correlation between FFA composition of OGTT after 2 hours and Homa-IR (P>0.05). The LPL activity of OGTT after 2 hours was negatively correlated with Homa-IR (P<0.05).Conclusion:1 The TFA and LPL activity of OGTT after 2 hours were lower than fasting with T2DM. Among fatty acids, the C16: 0, C16: 1, C18: 1, C18: 2, C18: 3 concentration were lower than fasting. With the increase of plasma glucose fluctuation, the TFA, FFA composition and LPL activity of fasting were not changed obviously, the TFA, C16: 0, C16: 1, C18: 1, C18: 2, C18: 3 of OGTT after 2 hours gradually decreased, and the LPL activity gradually decreased, too.2 With HbA1c increased, the TFA, C16: 0, C18: 0, C22: 0 increased and LPL activity decreased.3 The TFA was positively correlated with insulin resistance, LPL activity was negatively correlated with insulin resistance, and the C16: 0, C18: 0, C22: 0 of fasting were positively correlated with insulin resistance. |
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