| BackgroundsAlzheimer disease(AD)is an age-dependent neurodegenerative disorder.It is characterized by the progressive loss of cognitive ability is the mainly clinical characteristic of AD,with the appearance in the cerebrospinal fluid(CSF)showing the accumulation of the amyloid-?(A?)peptide into amyloid plaques in the extracellular brain parenchyma,as well as by intrcellular neurofibrillary tangles primarily comprised of hyperphosphorylated tau.By contrast,Parkinson disease(PD)is also an age-dependent neurodegenerative disorder.However,the clinical characteristics include tremor,rigidity and slowness of movements,which are related to the progressive loss of neurons in substantia nigra(SN)and the changes of cerebral structure as the progression of disease.Clinically,some characteristics of AD overlap the PD.PD patients are possible with cognitive impairment,even developing into dementia,as Parkinson disease with dementia(PDD).In the meantime,AD patients are with extrapyramidal disease,which is characterized as torsion spasm,trembling palsy and behavioral disorders.Adenosine triphosphate(ATP)-binding cassette transporter A1(ABCA1),translated by ABCA1 gene,participates in the cholesterol transport,as well as cleaning excess lipids,contributing to the balance of intracellular phospholipids.According to Wahrle et al.and Jasmin et al.,in the early stage of the repair of cerebral injury,ABCA1 played a part in the regulations of apolipoprotein E(ApoE)and cholesterol in glial cells.Sundar et al.found that ABCA1 accelerated the cleaning of A?,contributing to the repair of cerebral injury by regulating ApoA1,which was related to the pathogenesis of AD.Single nucleotide polymorphisms(SNPs)are variation in a single nucleotide that occurs at a specific position in the genome,where each variation is present to some appreciable degree with a population.However,fewer researches are focused on the relationship between ABCA1 SNPs and AD or PD.In the past few years,the regulation on lipid metastasis of ABCA1 was drawn lots of attentions,especially on regulating high-density lipoprotein(HDL).In Tangier disease(TD),ABCA1 promoted the decrease of HDL and influencing the macrophage foam cell formation.Chung et al.found that low-density lipoprotein(LDL)was down-regulated by silencing ABCA1 in mice,while triglyceride(TG)level was up-regulated,indicating the importance of ABCA1 in regulating total cholesterol(TC).However,previous studies were fewer focused on the relationship of ABCA1 SNPs with lipid metabolisms,especially the biomarkers as AD and PD.Additionally,though there were differences on clinical and pathological characteristics between AD and PD,many evidences showed the chronic neuroinflammations during the pathogenesis of AD and PD.Nagatsu et al.found that some levels of inflammatory factors increased in CSF and basal ganglia in PD patients,such as interleukin-1?(IL-1?),interleukin-6(IL-6),tumor necorsis factor-?(TNF-?)and so on,which also promoted the accumulation of A? in AD patients.When with injury or neuroinflammation in central nervous system(CNS),the permeability of blood brain barrier(BBB)increased,leading to the inflammatory factors entering CNS through BBB with high permeability or without permeability,contributing to the increase of inflammatory factors in CNS.Although previous researches proved the correlation between inflammatory factors in peripheral circulation or CNS and AD or PD.there was no evidence confirming whether these inflammatory factors could be the biomarkers and whether the changes of inflammatory factors related to ABCA1 SNPs.Therefore,we analyzed the ABCA1 R219K SNPs in AD and PD patients comparing to healthy people,in order to compare the difference among AD,PD and healthy people.By detecting the apolipoproteins(ApoA1,ApoA2 and ApoB),lipid metabolism related protein(HDL,LDL,TC and TG),and common inflammatory factors(IL-1?,IL-6 and TNF-?)in peripheral circulation,as well as analyzing the correlation between that mentioned above and the progression of AD and PD,in order to provide clinical diagnosis and prevention with molecular evidences.Part ? Correlation of ABCA1 R219K SNPs with Alzheimer disease and Parkinson disease1.1 ObjectivesTo investigate the correlation of ABCA1 R219K SNPs with the pathogenesis and progression by analyzing the different distribution of ABCA1 R219K SNPs in patients of Alzheimer disease(AD)and Parkinson disease(PD).1.2 Methods1.2.1 ObjectsAll the patients and healthy volunteers were the Han people living in Inner Mongolia(China)for more than 20 years.All the objects received homogeneity detection on age and sex,and were excluded the effects of neuronal active substance and other diseases.1)AD patients:105 AD patients received mini-mental state examination(MMSE),activity of daily living scale(ADL)and clock drawing test(CDT)as the evaluation on cognitive ability and activity of daily living.Hachinski ischemic scale(HIS)was for distinguishing AD from vascular dementia(VD).2)PD patients:116 PD patients received Hoehn-Yahr(H-Y)evaluation to estimate the progression,and then received MMSE,ADL and CDT to estimate the cognitive ability and activity of daily living.3)Healthy volunteers:100 healthy volunteers were taken as negative control(NC)and received MMSE,ADL and CDT for evaluating the cognitive ability and activity of daily living.1.2.2 Blood samples collectionFasting blood were collected from all the participants and kept at-28?.1.2.3 Genomic analysisDNA was extracted from each sample and the purity was detected.Polymerase chain reaction(PCR)was for amplifying ABCA1 R219K.Matrix-assisted laser desorption ionization time of flight time mass spectrometry(MALDI-TOF-MS)was for detecting ABCA1 R219K SNPs.1.3 Results1.3.1 Demographic dataSex(X2=0.895,P=0.410)and age(X2=4.979,P=0.053)were with homogeneity among AD,PD and NC groups(P>0.05).1.3.2 Comparisons of varied scores1)MMSE:Comparing the MMSE,there was significantly difference among the 3 groups(F=1728.886,P<0.001).Average MMSE in AD(16.59±1.52)was lower than that in PD(25.60±1.61)and NC(27.89±1.21),significantly(P<0.05).Average MMSE in PD was lower than that in NC,significantly(P<0.05).2)ADL:Comparing the ADL,there was significantly difference among the 3 groups(X2=1242.562,P=0.004).Average ADL in AD(39.41± 2.51)and PD(42.58± 3.33)were both higher than that in NC(25.43± 1.72),significantly(P<0.05).Average ADL in AD was lower than that in PD,significantly(P<0.05).3)CDT:Comparing the CDT,there was significantly difference among the 3 groups(X2=310.670,P<0.001).Average CDT in AD(1.90± 0.72)and PD(2.71±0.75)were both lower than that in NC(4.00±0.00),significantly(P<0.05).Average CDT in AD was lower than that in PD,significantly(P<0.05).4)HIS:Average HIS in AD was(2.56±0.14),lower than 4,identifying as AD.5)H-Y:Average H-Y in PD was(3.50± 0.81),considering as serious.1.3.3 Distribution of ABCA1 R219K1)Hardy-Weinberg equilibrium(HWE):Distribution of ABCA1 R219K in AD(X2=0.086,P=0.769)and NC(X2=0.0482,P=0.826)were accorded with HWE,while that in PD(X2=17.312,P<0.05)was not accorded.2)ABCA1 R219K genotypes:There was significant difference on the distribution of ABCA1 R219K genotypes among the 3 groups(F=6.372,P<0.05).The distribution of ABCA1 R219K genotypes between AD and PD,and between PD and NC were significantly different(P<0.05),while no significant difference between AD and NC.3)ABCA1 R219K alleles:The distribution of ABCA1 R219K alleles between AD and PD was significantly different(P<0.05),while no significant difference between AD and NC,or between PD and NC.4)R219K RR+RK v.s.ABCA1 R219K KK:There was significant difference on distribution of ABCA1 R219K RR+RK v.s.ABCA1 R219K KK genotypes among the 3 groups(F=6.372,P=0.002).The frequency of ABCA1 R219K RR genotype in AD(45.71%)was lower than that in PD(69.83%),while the frequency of ABCA1 R219K RK+KK genotype in AD(54.29%)was higher than that in PD(30.17%),significantly(P=0.012).The frequency of ABCA1 R219K RR genotype in PD was higher than that in NC(53.00%),while the frequency of ABCA1 R219K RK+KK genotype in in PD was lower than that in NC(47.00%),significantly(P=0.001).No significant difference on the frequency of ABCA1 R219K RR and ABCA1 R219K RK+KK between AD and NC.1.3.4 Association of genotypes with illness progressionThe ABCA1 R219K genotypes distribution was negatively correlated to the MMSE in AD(r=-0.222,95%CI=-0.386?-0.033,P<0.05).The average MMSE of AD patients carrying ABCA1 R219K RR genotype was higher,showing as slower progression,while that of those carry ABCA1 R219K RK or ABCA1 R219K KK was lower,showing as faster progression.The ABCA1 R219K genotypes distribution was negatively correlated to the H-Y in PD(r=-0.489,95%CI=-0.624--0.330,P<0.05).The average H-Y of PD patients carrying ABCA1 R219K RR or ABCA1 R219K KK genotypes was higher,showing as faster progression,while that of those carry ABCA1 R219K KK genotype was lower,showing as slower progression.1.4 ConclusionsABCAl R219K R was the protective allele in AD pathogenesis and progression.ABCA1 R219K K was the protective allele in PD pathogenesis and progression.The frequency of ABCA1 R219K RR+RK genotypes in AD and PD patients was lower than that in healthy volunteers.The frequency of ABCAl R219K RK+KK genotypes in AD patients was higher than that in PD patients.The frequency of ABCA1 R219K RK+KK genotypes in PD patients was lower than that in healthy volunteers.Part ? Correlation of ABCA1 R219K SNPs with serology in patients with AD and PD2.1 ObjectiveBy detecting serum ABCA1 and the related factor levels in AD,PD and healthy volunteers,as well as analyzing the correlation of ABCA1 R219K SNPs with the progression of AD and PD,we investigated the effect of ABCA1 R219K SNPs on the serum factors in AD and PD patients.2.2 Methods2.2.1 Detections on serum factorsSerum was separated with high-speed freezing centrifuge.Enzyme-linked immunosorbent assay(ELISA)was for detecting serum ABCA1,ApoA1,ApoA2,ApoB,HDL,LDL,TC,TG,IL-1?,IL-6 and TNF-? in AD,PD and healthy volunteers.2.3 Results2.3.1 Serum factors in AD,PD and healthy volunteersAverage levels of serum ABCA1,ApoA1,ApoA2,LDL,TC and TG in AD patients were both lower than that in NC,while serum ApoB,HDL,IL-1?,IL-6 and TNF-? were higher,significantly(P<0.05).Serum ABCA1,TC and IL-1? in AD patients were both lower than that in PD patients,while ApoA1,ApoA2,ApoB,HDL,IL-6 and TNF-? were higher,significantly(P<0.05).Serum ApoA1,ApoA2,ApoB and HDL in PD patients were higher than that in NC,significantly(P<0.05),while no significance on serum LDL,TC or TG between PD and NC.2.3.2 Association of ABCA1 R219K genotypes with serum factorsIn those carrying ABCA1 R219K RR+RK genotypes,there were significant differences of serum ABCA1,ApoA1,ApoA2,ApoB,HDL,LDL,TC,TG;IL-1p,IL-6 and TNF-? between in AD and in NC(P<0.05).In those carrying ABCA1 R219K KK genotype,there were significant differences of serum ABCA1,ApoAl,ApoB,HDL,TC,IL-1?,IL-6 and TNF-? between in AD and in NC(P<0.05),while serum ApoA2,LDL and TG were without significances.In those carry ABCA1 R219K RR or ABCA1 R219K RK+KK genotypes,there were significant differences of serum ABCA1,ApoA1,ApoA2,ApoB,HDL,TC,IL-1?,IL-6 and TNF-? between in AD and NC(P<0.05),while serum LDL and TG were without significances.In those carrying ABCA1 R219K RR+RK or ABCA1 R219K RR genotypes,there were significant differences of serum ABCA1,ApoA1,ApoA2,ApoB,HDL,IL-1?,IL-6 and TNF-? between in PD and NC(P<0.05),while serum LDL,TC and TG were without significances.In those carrying ABCA1 R219K KK or ABCA1 R219K RK+KK genotypes,there were significant differences of serum ApoA1,ApoA2,ApoB,HDL,IL-1?,IL-6 and TNF-? between in PD and NC(P<0.05),while serum ABCA1,LDL,TC and TG were without significances.2.3.3 Correlation of ABCA1 R219K genotypes with serum factorsSerum ABCA1 in AD patients was negative correlated to ABCA1 R219K(r=-0.596,95%CI=-0.705?-0.475,P<0.05).Serum ABCA1 of AD patients carrying ABCA1 R219K RR or ABCA1 R219 RK genotypes was higher,while that of those carrying ABCA1 R219K KK genotype was lower.Serum HDL in PD patients was positively correlated to ABCA1 R219K(r=0.692,95%CI=0.608-0.769,P<0.05).Serum HDL of PD patients carrying ABCA1 R219K RR or ABCA1 R219K RK genotypes was lower,while that of those carrying ABCA1 R219K KK genotype was higher.Serum IL-1?(r=-0.394,95%CI=-0.558?-0.223,P<0.05),IL-6(r=-0.448,95%CI=-0.595?0.290,P<0.05)and TNF-?(r=-0.516,95%CI=-0.633?-0.391,P<0.05)in PD patients were both negatively to ABCA1 R219K.Serum IL-1?,IL-6 and TNF-? in PD patients carry ABCA1 R219K RR or ABCA1 R219K RK genotypes were higher,while that of those carry ABCA1 R219K KK genotype was lower.2.3.4 Correlation of serum ABCA1 and other factors in AD and PD patientsNot matter in AD or in PD,serum ABCA1 was without correlation with serum ApoA1,ApoA2,ApoB,HDL,LDL,TC,TG,IL-1?,IL-6 or TNF-?.2.3.5 Correlation of serum factors with progression of AD and PDSerum IL-1?(r=-0.731,95%CI=-0.801?-0.650,P<0.05),IL-6(r=-0.752,95%CI=-0.819?-0.670,P<0.05)and TNF-?(r=-0.691,95%CI=-0.770?-0.600,P<0.05)were negatively correlated to MMSE in AD patients.Average MMSE in AD patients decreased accompanying with serum levels of IL-1?,IL-6 and TNF-?increasing,as the development of AD.Serum HDL(r=-0.439,95%CI=-0.576?-0.297,P<0.05)was negative correlated to H-Y in PD patients,while serum IL-1?(r=0.849,95%CI=0.799?0.886,P<0.05),IL-6(r=0.768,95%CI=0.696?0.828,P<0.05)and TNF-?(r=0.851,95%CI=0.802-0.893,P<0.05)were both positively correlated to H-Y in PD patients.Average H-Y in PD patients increased accompanying with serum HDL decreasing but serum IL-1?,IL-6 and TNF-? increasing,as the development of PD.2.4 ConclusionsThere were significant differences on lipid related factors and inflammatory factors in serum between in AD and healthy people,as well as between in PD and healthy people.Serum ABCA1,ApoA1,ApoA2,ApoB,HDL,TC,IL-1?,IL-6 and TNF-? were with significances between in AD and in PD.ABCA1 R219K R allele might be factor inducing abnormal levels of serum ApoA2,LDL and TG in AD patients,as well as abnormal serum ABCA1 in PD patients.ABCA1 R219K K allele might be the risk factor inducing lower serum ABCA1 in AD patients.ABCA1 R219K R allele might be the risk factor inducing lower HDL but higher IL-1?,IL-6 and TNF-?.Seurm IL-1?,IL-6 and TNF-? would increase as the development of AD and PD,while serum HDL would decrease as the development of PD. |
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