| Backgroud:Periodontitis is a common infectious disease caused by microbial biofilms, con-sisting of inflammation of the gingiva, formation of periodontal pocket, progressive loss of periodontal attachment and destruction of alveolar bone. Although periodontitis is initiated by microbial biofilms, plaque microorganisms is not sufficient to explant the differences in disease severity. Recently, more and more evidences show that certain risk factors,such as diabetes and other systemic diseases and genetic factors,do not directly cause the periodontitis, they just affect the development and severity. Some results show that:the risk of periodontal disease in diabetic patients was significantly higher than healthy people.Diabetes mellitus is a metabolic disease of multiple causes.Type 2 diabetes mellitus is the most common form (90%-95%) of diabetes, which usually occurs in patiens between the age of 35 to 40 years.For a long time,insulin secretory dysfunction and insulin resistance has been considerde as main pathogenesis of type 2 diabetes mellitus.Recently,studies suggest that type 2 diabetes mellitus is a congennital autoimmune disease,which may be induced by inflammatory cytokine.Inflammation plays a role of media in the pathogenesis of type 2diabetes mellitus.The role of inflammatory factors played in progress of periodontitis has been fully Affirmed,and inflammation in insulin resistance and P cell injury during the process play a critical role has also been confirmed by the researches. C-reactive protein is widely used as a clinical marker of inflammation, many studies have found that the relationship between CRP and the development of periodontitis and diabetes. The results show that:there was a positive association between periodontitis severity and serum CRP level, and CRP in type 2 diabetes is an important predictor. Elwvated serum CRP levels is a common reation of periodontitis and diabetes.It opeaned a new field to explore the internal relations between them.So is CRP the massger of periodontitis and systerm diseases,or just a clinical marker of inflammation?C-reactive protein is an acute phase protein, synthesized mainly by the liver under the stimulation of cytokines such as IL-1β, IL-6, TNF-α, interferon, and TGF-β. A small amount of CRP can be generated by peripheral blood lymphocytes.The rise in blood CRP after tisuss insult or injury is rapid and robust, and then gradually decreased when the lesions get improved. It can enhance leukocyte reactivity,complement fixation and cleanup cell debris of the site of infection.CRP has the function of immune recognition and immune regulation.It is a sub-clinical infection sensitive indicator.Studies have found that the CRP level was regulated by the combined effects of genetic and environmental factors, the 35% to 40% of the individual's differences on CRP level could be attributed to the genetic factors. Currently, it has been found that nearly 40 kinds of single nucleotide polymorphisms within CRP gene. Now,some of the SNPs or haplotypes have been asscciated with serum CRP level.So far, most researches on CRP gene polymorphisms focused mainly on their association with cardiovascular disease. Invesstigtions on the relationship between C-reactive protein gene polymorphisms and diabetes or periodontal disease are relatively scarce.In our study, we detectde the serum CRP and HbA1c level, and the distribution of C-reactive protein gene polymorphisms, then respectively analyzed the relationship between C-reactive protein gene polymorphisms and CRP,HbA1c level;we detectde the change of CRP and HbA1c level after periodontal treatment, then respectively analyzed the relationship between C-reactive protein gene polymorphisms and the change of CRP,HbAlc level.Chapter OneObjective:To analyze the relationship between C-reactive protein gene polymorphisms and serum CRP level in type 2 diabetes with chronic periodontitis.Methods:Subjects had been collected from three hospitals of Guangzhou City from September 2008 to September 2009. Inclusion criteria:①diagnosed as diabetes for more than 1 year in stable condition, no changes of medication within the past 2 months, no serious complications;②chronic periodontitis and> 16 teeth left, without systemic periodontal treatment and no scaling within the past 1 year. Exclusion criteria:①with other systemic diseases such as coronary heart disease;②in addition to periodontitis, other active inflammation existed;③administration of antibiotics within past 4 weeks;④pregnancy, or lactation;⑤refused to participate in this study. Blood samples of each subject were collected at 8-10 AM.,which were used to detect hight-sensitivity C-reactive protein (hsCRP).Direct sequencing and PCR-RFLP methods were used to test CRP -286,-409,-757,-717,+1059 and +1444 single nucleotide polymorphism.The Kruskal Wallis test and Mann-Whitney test were used to detect the difference between various CRP SNPs and CRP levels. If there were significantly difference, using the x2 test to analyze the genotype and gene frequency distribution between the two groups.Results:1. Hardy-Weinberg equilibrium test.The 5 CRP SNPswere found meet Hardy-Weinberg equilibrium (P> 0.05)2. The distribution of CRP genotypes and alleles in type 2 diabetic patients with chronic periodontitis.The main genotype of CRP:TT homozygote of -757 T> C, AA homozygote of -717 A>G, CC homozygote of-286 C>A> T, GG homozygotes of+1059 G> C and CC homozygote of+1444 C>T.For -409 G> A site, all were GG homozygote. For +1059 G> C site, CC genotype was not found.3. CRP gene linkage disequilibriumIn this study, there existed a strong linkage disequilibrium for CRP-286 C> A> T and -757 T> C (r2=0.648).4. CRP gene between loci haplotype analysisIn this study,5 haplotypes (CAAGC, TACCC, TACGC, TATGT and TGCGC), were found, and TACGC (51.0%)was the major haplotype.5. The relationship between CRP gene polymorphisms and the serum CRP levelsFor CRP-757 T>C,-717 A>G, and -286 C>A>T, there were significant differ-ences between CRP levels with different genotypes, for+1059 G>C and+1444 C> T there was no significant difference (P> 0.05) between CRP levels with different genotypes.Chapter TwoObjective:To explor the correlation between C-reactive protein gene polymorphisms and HbA1c levels in type 2 diabetes patients with chronic periodontitis.Methods:The details of subjects and CRP genotypes analyze can find in Chapter ONE. Blood samples were analyzed for HbA1c.The association between CRP gene polymorphisms and the baseline HbA1c levels were analyzed with Kruskal Wallis test and Mann-Whitney test.Results:There was no significant differences between the HbAlc levels and CRP SNPs (P> 0.05).Chapter ThreeObjective:To study the relationship between CRP gene polymorphisms and the changes of CRP levels after periodontal treatment for type 2 diabetes patients with chronic periodontitis.Methods:90 subjects received periodontal treatments at the first time and supportive periodontal therapy (SPT) at 3-month follow-up visit. The treatment include OHI, supragingival scaling, subragingival currettage, root planning, occlusal adjustment, and extraction of hopeless tooth. CRP gene polymorphisms were ananlyzed as in Chapter one. Serum hs-CRP levels were measured at 6 months of treatment for each subjects.The association between CRP gene polymorphisms and the change of HbA1c levels after the periodontal treatments were analyzed with Kruskal Wallis test and Mann-Whitney test.Results:There was no significant differences between the change of CRP levels and various genotypes (P> 0.05).Chapter FourObjective:To study the relationship between CRP gene polymorphisms and the changes of CRP levels after periodontal treatment for type 2 diabetes patients with chronic periodontitis.Methods:CRP gene polymorphisms were ananlyzed as in Chapter one.The periodontal treatments were done in Chapter three. HbA1c levels before and after treatment were measured for each subjects.The association between CRP gene polymorphisms and the change of HbA1c levels after the periodontal treatments were analyzed with Kruskal Wallis test and Mann-Whitney test.Results:In this study, for CRP+1444 C> T, there was significant differences of HbAlc levels between subjets with different genotypes.Patients who carring the TC+TT genotypes were susceptible to the periodontal treatments.For-757 T> C,-717 A> G,-286 C> A> T and +1059 G> C site, there was no significant difference of the change of HbA1c levels between subjects with various genotypes (P> 0.05).Conclusion:1. In diabetic patients with periodontitis CRP -757 T>C,-757 T>C,-286 C>A>T were associated with hsCRP level;-757 C allele,-757 G allele,-286 A allele were relevant to hsCRP level.2. CRP+1444 C> T locus was associated with changes of HbAlc levels;Patients who carring CT+TT genotypes were susceptible to the periodontal treatments.3. Evidence were not enough to support CRP+1059 G> C and +1444 C> T were relevant to hsCRP level.4. Evidence were not enough to support CRP gene polymorphisms were relevant to HbA1c level.5. Evidence were not enough to support CRP gene polymorphisms were relevant to the changes of CRP levels after periodontal treatment.6. Evidence were not enough to support CRP CRP-757 T> C,-717 A> G and -286 C> A> T and +1444 C> T were relevant to the changes of HbA1c levels after periodontal treatment.7.For the genotype distributions of CRP-286 C> A> T and +1444 C> T, Chinese subjects have the similar genetic background with Japanese,but different with US subjectsand the European. |
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