Correlation Of Free Fatty Acids And Lipid-metabolism-related Cytokines With Metabolic Syndrome

Objective To investigate the changes of serum free fatty acids (FFAs) composition in the patients with metabolic syndrome (MS) and the relationship between FFAs with serum glucose disorder.Methods The serum free fatty acids profile was measured by the gas chromatograph and mass spectrometer(GC/MS) in 53 patients with metabolic syndrome,43 patients with type 2 diabetes(T2DM) and 31 control subjects.Results①The patients with T2DM had higher parameters of unsaturated fatty acids UFA (C18:2,C18:1,C20:4,C22:6,C20:3), among them,C18:2,C18:1,C20:3 were significantly increased in the patients with T2DM than those in the normal control (all P<0.05),saturated fatty acids SFA(C16:0,C18:0)and ratio of SFA/TFA(total fatty acids)were remarkably decreased in patients with T2DM(P＜0.01, compared with normal control), the ratio of UFA/TFA,PUFA(polyunsaturated fatty acids)/TFA, PUFA/SFA and n6 PUFA/n3 PUFA were significantly increased in the patient with T2DM compared with normal subjects (P<0.01).②The patients with MS had higher parameters of unsaturated fatty acids UFA (C18:2,C18:1,C20:4,C22:6,C20:3), among them, C18:2,C18:1,C22:6,C20:3 were significantly increased in the patients with MS than those in the normal control (P＜0.01), the ratio of UFA/TFA, PUFA/TFA, PUFA/SFA, n6 PUFA/n3 PUFA were significantly increased in the patient with MS compared with normal subjects (P<0.01), C16:0,C18:0 and SFA/TFA were remarkably decreased in patients with MS (all P<0.05, compared with normal control).③The patients with MS had lower C18:2,UFA/TFA,PUFA/TFA,n6/n3 than those with T2DM (all P＜0.05), but C22:6,C18:3 SFA/TFA were remarkably increased in patients with MS (all P<0.05, compared with T2DM).④Fasting blood glucose had remarkably positive correlation with UFA/TFA,PUFA/TFA,PUFA/SFA,n6/n3 (r=0.193,0.174,0.193,0.182, all P<0.05), and a negative correlation with SFA/TFA (r=-0.193,P<0.01). After BMI calibration, Fasting blood glucose was still positively correlated with UFA/TFA,PUFA/TFA,PUFA/SFA,n6/n3(r=0.185,0.168,0.194,0.183,allP<0.05), and negatively correlated with SFA/TFA (r=-0.189, P＜0.01).Conclusion The UFA, UFA/TFA and PUFA/SFA are higher in the patients with MS and T2DM than normal subjects, it demonstrated there is the FFAs metabolic abnormality in those patients. The patients with T2DM is easier to get injured by lipid peroxidation than the patient with MS. Fasting blood glucose positively correlated with UFA/TFA,PUFA/TFA,PUFA/SFA,n6/n3 and a negatively correlated with SFA/TFA, increased levels of n6 PUFA may play a role in the pathogenesis of MS and T2DM. Objective To investigate the effects of free fatty acids(FFAs) on secretory function and the gene expression profiling of pancreaticβ-cell line MIN6, and to evaluate the potential protective effects of N-acetyl--L-cysteine(NAC).Methods The MIN6 cells are treated for 72 h with either①BSA,②OA (Oleic acid) in BSA,③OA in BSA plus NAC,or④NAC in BSA respectively, then The concentration of insulin in the supernatant and total cellular insulin content are determined by radioimmunoassay. Total RNA was isolated from MIN6 cells and converted to cDNA, oligonucleotide microarrays are used to define gene expression, using software analysis Expression profiling of genes and further classified according to biological function. Genes that were deemed significantly altered by OA treatment are further detected and characterized by Real-time PCR.Results①OA increased basal insulin, but decreased insulin secretion induced by glucose. Coincubation with NAC did not improve the insulin secretion in response to glucose or normalize increased basal insulin secretion in OA-exposed MIN6 cells.②OA decreased insulin content in MIN6 cells by about 50% compared with BSA control, coincubation with NAC restored insulin content in OA-treated MIN6 cells.③Of the 12,000 genes or ESTs, OA decreased expression of 667 and upregulated genes of 265. Coincubation with NAC markedly reduced the number of OA-down regulated genes or ESTs from 667±66 to 192±29 (P< 0.05 for OA vs. OA+NAC). The number of upregulated genes and ESTs was not significantly reduced (265±88 to 212±14, P= 0.77 for OA vs.OA +NAC).④A total of 45 genes deemed significantly changed by the microarray analysis were further confirmed by real-time PCR, PCR confirmed all 16 genes changed by> 1.8-fold,28 genes shown to be changed by> 1.2-1.3 fold. according to known function, OA signifi-cantly upregulated genes involved inβ-oxidation of lipids comprised the largest functional cluster with 32%,Genes clustered into cell growth/ differentiation and signal transduction groups represent 13% and 16% of the clustered genes, respectively. OA also regulated several genes involved in transcription, protein trafficking and secretion, nucleosome assembly, and cellular defense response, comprising 2-9% of the clustered genes. Genes involved in cell growth and differentiation were normalized by coincubation with NAC, but all genes in the metabolism cluster differentially regulated by OA were not normalized by NAC treatment.Conclusion①Long-term exposure of MIN6 cells to OA leads to increase in basal insulin secretion with an inhibition of GSIS, it is thought to contribute to the deterioration of islet function in theβ-cell. and antiox- idants NAC failed to restore GSIS following OA suggests that the increase in ROS production associated with chronic OA treatment of P-cells may not be directly implicated in the effects of OA on GSIS.②Prolonged exposure to FFAs inhibits insulin biosynthesis results in decreased insulin content and insulin maturation, and that this could be restored by NAC.③OA significantly changed genes involved in P-oxida-tion of lipid metabolism, but the expression of genes involved in glyco-lysis and glucose oxidation was generally unchanged.④By analyzing the gene expression profiling, many candidate genes associated with lipotoxicity to (3-cells are offered and it put a foundation for future research. Objective To evaluate new cytokines associated with dyslipidemia including adiponectin, angiopoietin-like protein 3(Angptl3) and retinol-binding protein 4(RBP4) in metabolic syndrome(MS).Methods Serum adiponectin,Angptl3 and RBP4 levels were measured by sandwich ELISA in a group of 111 patients with metabolic syndrome(MS) and 152 normal controls to analysis the relationships between those new cytokines and dyslipidemia in MS.Results①Serum adiponectin levels in men were significantly lower than those in women (P＜0.001), Serum RBP4 levels in men were significantly higher than those in women (P＜0.001), After BMI calib-ration, those difference still exist, but After BMI and fat content percen-tage calibration, those difference disappeared. No gender- associated difference in serum Angpt13 levels was observed (P=0.384).②Serum adiponectin levels were positively correlated with high density lipopro-teinemia-C (HDL-C) and Angpt13 after adjusted for age and sex(P<0.05), negatively correlated with BMI, WC, WHR, fat percentage, FPG, TG, FINS, HOMA-IR and hsCRP (P<0.05), after adjusted for age, sex and BMI, adiponectin levels were positively correlated with HDL-C and Angpt13 and negatively correlated with FPG, TG, FINS and HOMA-IR and (P＜0.05), but the correlation with WC, WHR, fat percentage and hsCRP disappeared. Serum Angpt13 concentrations were positively correlated with adiponectin (P＜0.001) after calibration of age and sex, negatively correlated with FINS and HOMA-IR (P=0.026, P=0.015), after calibration of age, sex and BMI, Angpt13 till positively correlated with adiponectin(P＜0.001),but negative correlation with FINS and HOMA-IR disappeared (P=0.118, P=0.086). Serum RBP4 concentrations were positively correlated with BMI, WC, WHR, fat percentage, PBG,TG,TC,LDL-C,SBP,DBP,FINS,HOMA-IR after adjusted for sex and age(P<0.05),negatively correlated with HDL-C (P=0.012). after cali-bration of age, sex and BMI, Serum RBP4 concentrations were positively correlated with PBG,TG,TC,LDL-C,SBP,DBP (P<0.05),negatively correlated with HDL-C(P=0.055), but correlation with FINS,HOMA-IR and fat percentage disappeared.③By multiple regression, TG, Angpt13, sex, and HOMA-IR were found to be independent determinants for serum adiponectin concentrations. The adiponectin was the independent deter-miner influencing angpt13 level. TG, sex, DBP were independent deter-minants for serum RBP4.④Serum adiponectin levels were significantly lower in the hypertriglyceridemia than in the control group [4.40(0.97-23.29)vs.6.67 (1.12-22.27) ug/ml, P=0.001] and significantly lower in the hypo-high density lipoproteinemia group than in the control group [4.96(0.97-14.88) vs.5.18(1.12-23.29) ug/ml, P=0.005)] after calibration of age, sex and BMI. Serum RBP4 concentrations were significantly higher in the hypertriglyceridemia group than in the control group) after calibration of age and sex (55.22±17.72 vs.45.21±17.72ug/ml, PO.001). After calibration of age, sex and BMI, RBP4 concentrations was still higher in hypertriglyceridemia group than in the control group (F=9.549, P=0.002). No difference in serum Angpt13 levels was observed between hypertriglyceridemia group and control group, between hypo-high density lipoproteinemia group and the control group[(424.69±154.06 vs.421.92±138.16 ng/ml,P=0.878),(428.46±134.06 vs.416.94±158.81 ng/ml, P= 0.531) respectively].⑤Serum adiponectin concentrations were signifi-cantly lower in the Non-alcoholic fatty liver disease (NAFLD) group than in the control group(P<0.001). Serum RBP4 were significantly higher in the NAFLD group than in the control group(P<0.001). No difference in serum Angpt13 levels was observed between the NAFLD group and the control group (P=0.256).Conclusion①Serum adiponectin is negatively correlated with all components of MS, NAFLD sufferers show significantly lower adiponectin, prompting that the decrease of adiponectin content may be a reason of MS progress.②Angpt13 is independent positively correlated with adiponectin, and has no obvious relationship with dyslipidemia and other components of MS. Because the mechanism of lipid metabolism is different, the effects of Angpt13 in human being should be further studied.③Serum RBP4 has closely relationship with blood fat, central obesity, HOAM-IR, NAFLD and etc of MS components, it may be one of main adipocyte factors associated with lipid metabolism, prompting that Serum RBP4 may be a new serum marker of metabolic syndrome.