Association Study On The CD33 Rs3865444 Polymorphism With Cognition And Lipid Levels In Longevity Of Hongshuihe River Basin

Background:CD33 is a type I transmembrane glycoprotein which is widely distributed in blood, bone marrow and lymphocyte surface, belonging to the immunoglobulin superfamily and Sialic acid-binding immunoglobulin-like lectins(Siglecs) Family. It is involved in the regulation of cell growth, differentiation, apoptosis and secretion of related factors, playing an important role in cellular immune responses. In addition, CD33 has a relationship with processing of cognition decline, its associated research is not much. The influence of CD33 rs3865444 on cognitive function and human life is inconclusive.Objectives:To look at the possible relationship between CD33 rs3865444 polymorphism and cognition and serum lipid levels and its putative role in human longevity in the long-lived families inhabiting along Hongshuihe River Basin in Guangxi Province.Methods:1981 people were divided into three groups:the long-lived families inhabiting along Hongshuihe River Basin in Guangxi Province(aged≥ 90 years) is the longevity group (645 person), non-longevity families in Hongshuihe River Basin (aged 60-77 years old) is the local control group (674 person), non-longevity families in Hezhou (aged 60-77 years old) is Hezhou control group(662 person). Measure the height, weight, measurements, blood pressure, lipids, and genotyping CD33 rs3865444 by improved multiplex ligase detection reaction (iMLDR) technology, find the relevance of the polymorphism and cognition.Results:1. Comparison of clinical data among families:The level of TG in the longevity group and the local group were significantly higher than Hezhou group, there was the opposite trend of HDL-C; the level of ApoA in the longevity group were significantly lower than the other two groups (P<0.01), but there was no significant difference in other indexes.2. The genotypic and allelic distribution of CD33 rs3865444:In overall population, the major genotype were CC, whose frequency were 73.1%; the frequency of genotype(CA) and genotype(AA) were 23.8% and 3.1%, the major allele were C, whose frequency were 85.0%. There was no significant difference about the frequency of genotype and allele. When stratificated by gender, the frequency of genotype CC and allele C of the males in longevity group are higher than remales; genotype CC of males in Hezhou control group was significantly lower than females.3. MMSE situation of three groups:There was no significant difference among MMSE score, but the time orientation and memory of Hezhou control group were significantly better than the longevity group, the time orientation of remales in the control group was better than Hezhou control group. The percentage of cognitive impairment in the longevity group was higher than the control group and Hezhou group, but the percentage in the control group was significantly lower than Hezhou group.4. The impact of CD33 rs3865444 polymorphism on MMSE:In males, the expression and memory of the allele A was lower than non- allele A.5. The impact of CD33 rs3865444 polymorphism on lipids:TG lipid levels of the longevity group and the local group were lower when he was allele A carriers. When stratificated by gender, the TC, LDL-C, ApoB levels of the longevity group males allele A carriers were higher than non- allele A carriers.6. Correlation analyses:In overall population, cognitive function was negatively correlated with age, positively correlated with education acquirement.Conclusion:The decrease of the allele C mutation rate in longevity group males may be a protective factors of keeping good expression and memory functions, which maybe related with low TC, LDL-C, ApoB levels.