| Background and PurposeAccording to the role of cytokine in the immune response and inflammation, itcan be classified as proinflammatory cytokine and anti-inflammatory cytokine.Interleukin-1β(IL-1β) is a major inductor of immune response, and it's binding withIL-1 -receptor may activate the immune response and inflammation reaction, whichmake IL-iβinvolved in the pathophysiologic mechanisms of atherosclerosis andcerebral infarction. Tumor necrosis factor-β(TNF-β) is classified as aproinflammatory cytokines. Lymphocytes may secrete TNF-βwhen they wereinduced by antigen or mitogen. TNF-βhas complex biological activities, which makeit extensive involved in inflammatory response and the development and regulation ofimmune system. TNF-βcan be self-induced and induce the secretion of othercytokines, such as IL-1, Interleukin-6 (IL-6) etc. Interleukin-10 (IL-10), ananti-inflammatory cytokine, is secreted by the Th2 cells. The function of IL-10 is toinhibit the cellullar immunologic response and inflammation. Proinflammatoryfactors and anti-inflammatory factors interaction each other. They play a crucial rolein the pathological mechanisms of progress and prognosis of atherosclerosis,autoimmune diseases, infection and so on.An increasing body of evidence demonstrates a close interplay betweeninflammatory factors and lipoprotein metabolism, and the two reinforce each other toparticipate in the pathophysiology of diseases. Inflammatory factors can regulate thelipid metabolism, resulting in hyperlipidemia. This function of inflammatory factors was fully proved by their effect on the formation of atherosclerosis and infection. Inaddition, inflammatory factors can destroy the homeostasis of lipid metabolism byregulating LDL receptor or the activity of related hepatic enzymes. In contrast,dyslipidemia can affect the synthesis, secretion and function of cytokines. Lipoproteincan act as promoting inflammatory mediators to induce the releasing of inflammatoryfactors, such as IL-6, TNF, IL-1 and so on. Researches show that hyperlipidemiaalways accompanied with the increased serum concentrations of inflammatory factors,especially in the level of C-reactive protein (CRP). This is another related evidence ofthe association between inflammatory factors and lipid metabolism disorder.On the relationship between inflammatory factors and dyslipidemia, althoughmany basis, but the hub and mechanism between them is not clear.Researches on thegene polymorphisms of inflammatory factors and related diseases provide us with abasis and ideas. From the perspective of the genetics variation to study the associationbetween inflammatory factors and dyslipidemia may be a good way. Our preliminaryexperiments, a normal crowd of China was involved, found firstly in domestic andinternational that carriers of GA genotype in interleukin-10-1082 site hadsignificantly higher serum concentration of high-density lipoprotein (HDL) than thatof AA genotype carriers, and proved that there were significant differences ininterleukin-10-1082 G/A genotype distribution between patients with cerebralinfarction and the control group.Based on the above, we speculate the gene polymorphisms of IL-1β, TNF-p andIL-10 may be closely related to dyslipidemia, and the polymorphisms may be the baseof relationship between inflammatory factors and dyslipidemia. To investigate thepolymorphisms of IL-1β+3953,TNF-β+252 and IL-10 -592 in Chinese HanPopulation and the association among gene polymorphisms in three positions, serumconcentrations of lipoprotein and cerebral infarction, we conducted a cross-sectionalstudy. Materials428 healthy Chinese Han subjects (Nor. group) and 126 patients with cerebralinfarction (CI. group) were recuited, who were in medical examination center or Neurology wards of Nan Fang Hospital. Physical examination, BP, blood routine andbiochemical examination had been done with every subject. Delete the samples withdyslipidmia, liver function failure, renal failure, heart failure, serious infection,malignant tumour, rheumatic disease of the heart, or physical sign and symptom ofinfection, surgery and injury, and lipid micmodulating drug taking in 4 weeks. Allpatients of CI meets with diagnostic standard mended in the Fourth CerebrovascularDisease Meeting, and were confirmed in clinical and scanned by CT or MR. The 102samples of the control group (Con. group) were derived randomly from the subjectsin the Nor. group, who are older than 35 years old.Methods1. Genomic DNA were extracted by Blood Genome DNA Extraction Kit, andwere stored in-20℃.2. We detected, using the PCR restriction length fragment polymorphisms assay(PCR-RFLP) and agarose gel electrophoresis method, the distribution of genotypes inIL-1β+3953,TNF-β+252 and IL-10-592 sites of samples with RsaI, TagI, Ncolenzyme respectively.3. Serum concentrations of total cholesterol (TC), TG, low density lipoprotein(LDL), HDL, Very low density lipoprotein (VLDL) were determined by OLYMPUSAU5421 automatic biochemistry analyzer.Results1. In Nor. group, eliminating the samples with poor DNA or PCR production,336 samples in IL-1β+3953 site ,and 376 samples in TNF-β+252 site and 356samples in IL-10-592 site were available in totally 428 blood samples. Result showsthat there are nine genotypes we got, as IL-1β+3953 (CC, CT, TT), TNF-β+252 (GG,GA,AA) ,IL-10-592(CC, CA, AA). The frequencies of CC, CA, AA genotypes atIL-10 gene promoter -592 position was 10.96% ,41.57% and 47.47%; those of CC,CT, TT genotypes at IL-1β+3953 position was 75.30%, 23.51% and 1.19%; andthose of GG, GA, AA genotypes at TNF-β+252 position was 22.34% , 44.68% and32.98%. No significant difference was found in distributions of gender and age in different genotypes in three sites (P>0.05).2. In Nor. group, the frequencies of alleles IL-10 -592C/A were 31.74% and68.26 %; and those of alleles IL-lβ+3953 C/T and TNF-P +252 G/A were 87.05%,12,95%, 44.68% and 55.32%. The frequencies of three sites in Chinese Hanpopulation are significantly different from those of other populations.3. In Nor. group, the concentrations of TC and LDL in sample with TNF-P+252GA genotype was significantly higher than those in sample with TNF-P +252AAgenotype (t=-2.406, P= 0.017; t=-2.516, P=0.0\2). And the concentrationofLDLinsample with 1L- 1β+3953CT genotype was significantly higher than that in samplewith IL-ip +3953CC genotype(2.743±0.723mmol/L vs. 2.502±0.699 mmol/L, t=-2.639, P=0.009). But, there were no significant difference of TG, TC, HDL, LDL andVLDL among the IL-10 -592CC genotype, IL-10 -592CA genotype and IL-10-592AA genotype (P>0.05) .4. Reference to the diagnostic criteria: LDL-C>3.64 mmol/L as abnormal, thesubjects of Nor. group were divided into groups of high - LDL group, and normal-LDL. The significant difference of gene polymorphism in IL-1β+3953 C/T sitebetween High-LDL and Normal-LDL group was found (x2=3.884, P=QM6), and thefrequency of T allele in IL-10+3953 site in High-LDL group is higher than that inNormal-LDL group (22.00% vs.12.25%). Reference to the diagnostic criteria:TC>5.72 mmol/L as abnormal, the subjects of Nor group were divided into groups ofHigh-TC group, and Normal-TC. The significant difference of gene polymorphismin IL-10 -592 C/A site and TNF-β+252 G/A site between the two groups was found(X2=3.529,P>=0.036; x2=7.002, P=0.005) .5. hi Cl.group, eliminating the samples with poor DNA or PCR production,84samples in IL-10 -592 site were available in totally 126 blood samples. Thefrequencies of CC, CA, AA genotypes at IL-10 gene promoter -592 position was9.52% ,40.487% and 50.00%.The difference of genotypic distribution and allelefrequencies in IL-10 -592 site between CI. group and Con. group is significant(X2=7.774, P=0.024; X2=.063, P=0.005). Conclusion1. For Chinese Han population, there are three genotypes both in IL-lβ+3953position (CC, CT, TT), and TNF-β+252 position (GG, GA, AA), as well as threegenotypes in IL-10 -592 site (CC, CA, AA).2. We first reported that the concentrations of TC and LDL in samples with GAgenotype in TNF-β+252 position was significantly higher than that in samples withAA genotype. And the concentration of LDL in samples with IL-10+3953 CTgenotype was significantly higher than that in samples with IL-10+3953CC genotype.3. There is significant difference of allele frequencies between control andpatients with dyslipidemia in three gene sites of IL-1β+3953 C/T> TNF-β+252 G/Aand IL-10 -592 C/A. Patients with high LDL may have higher frequency of the IL-10-592 A allele and TNF-β+252 G allele. Similarly, patients with high TC may havehigher frequency of T allele in IL-1β+3953 site. This may be one of the reasons forgenetic susceptibility in hyperlipidemia.4. There was correlation between gene polymorphism of IL-10 -592C/A andcerebral infarction, and IL-10 -592 A allelic gene frequency had positive correlationwith the liability of cerebral infarction.
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