Alterations Of Intestinal Flora And Its Relationship With Intestinal Features In Parkinson’s Disease Patients

Background:Parkinson’s disease(PD)is a neurodegenaration disease characteristiced by bradykinesia,tremor,muscle rigidity and postural balance disorder.Accumulation of pathologic α-synuclein(α-syn)in neurons and loss of dopaminergic neurons in substantia nigra are main neuropathological changes.The diagnosis of PD has been always dependent on motor symptoms occurred later in the course of disease.Recently,non-motor symptoms including gastrointestinal symptoms,sleep disturbances,mood abnormalities,loss of smell gradually have captured the attention of people,which appears before motor symptoms.There are lots of studies indicate almost all of the patients with PD have various non-motor symptoms that bring much more serious impact on the quality of life than motor symptoms.Furthermore,non-motor symptoms are the first clinical manifestations in more than 20%of individuals.As the most primary non-motor symptom of PD,gastrointestinal dysfunction occurs in patients with various forms of dysphagia,weight loss,tooth degeneration,excessive salivation,gastroparesis,constipation,anorectal dysfunction and so on.The incidence of constipation is as high as 80%in one study about PD patientss and often precedes the onset of motor symptoms decades.Accumulative evidence has demonstrated the PD may originate from gut.A research stated men who had fewer than 3 bowel movements per week were nearly 5 times more likely to develop PD within 6 years than normal people.Another study on patients with colonoscopy due only to intestinal lesions found partial patients had prodromal symptoms of PD and the incidence was positively correlated with the accumulation of α-syn in the colon.The intestinal tract may be one of first sites affected by pathogenic α-syn,and it may act as a conduit for the spread of α-syn,triggering the characteristic spread of pathological α-syn in the central nervous system.The gut microbiota may act as an environmental trigger,activating microglia in mice overexpressing α-syn to promote neuronal degeneration and motor dysfunction,which is consistent with observed intestinal flora disorders in patients with PD.ObjectiveIntestinal flora diversity and structural composition were analyzed by 16S rRNA gene sequencing technology for high-throughput sequencing of 16S rRNA variable region V3-V4 from all fecal samples.The colon permeability was assessed by immunofluorescence technology.The colonic mucosa pα-syn was detected by immunohistochemistry technology and the correlation between intestinal flora changes and intestinal features was explored via spearman correlation analysis.Methods1.30 patients with PD were recruited from March 2021 to August 2021 of the First Affiliated Hospital of Zhengzhou University,and 30 normal control(NC)were recruited in the Physical Examination Center of the First Affiliated Hospital of Zhengzhou University.The disease course of all subjects,gender,age,body mass index,smoking rate,a daily dose of levodopa dosage,modified Hoehn-Yahr(H&Y)grading,Unified Parkinson Disease Rating Scale Ⅱ(UPDRS Ⅲ)scores,constipation duration and Wexner scores of PD patients,MMSE scores,time up and go test scores of all participants were collected.2.Stool samples were collected from all subjects and total DNA was extracted.Specific primers were selected to amplify V3-V4 region of 16S rRNA,and high-throughput sequencing technology was used for sequencing.Analysis of theα-diversity,β-diversity and the difference of composition and structure in intestinal flora of two groups.3.The intestinal permeability and pα-syn in colon of subjects were accessed by immunofluorescence assay and immunohistochemistry.4.The correlations of gut microbiota with intestinal features such as Wexner score,intestinal permeability and pα-syn were analysed.Results1.The incidence of constipation in patients with PD was 73%(22/30),the average duration of constipation was(12.4±6.7)years,and the average Wexner score was(13.24±3.95).2.The α-diversity in PD patients was higher than that of NC.There were some differences in the composition of the intestinal flora between the two sample groups.3.At the phylun level,the abundance of Bacteroidetes was higher in stool samples from patients with PD(P<0.05).However,the abundance of Firmicutes and Actinobacterium was higher in the control group(P<0.05).At the genus level,the relative abundance of Escherichia-Shigella,Bacteroides,Bifidobacteria,Megamonas and Ruminococcus_torques_group in PD group was higher than those in NC group(P<0.05),while the abundance of Prevotella,Faecalibacterium and Roseburia was lower than those in NC group(P<0.05).4.The expression level of Ecadherin and ZO-1 decreased and the deposit of pα-syn increased in colon mucosa of PD patients compared to NC.In PD patients,the relative abundance of Bacteroides and Roseburia were positively correlated with the Wexner score but Megamonas was inversely correlated with the Wexner score.The relative abundance of Prevotella was positively correlated with the level of Ecadherin and ZO-1.The relative abundance of Faecalibacterium was positively correlated with Ecadherin,while the relative abundance of Escherichia-Shigella was negatively correlated with the ZO-1 and positively correlated with the expression of pα-syn in colon mucosa.Conclusions1.As the common non-motor symptom,constipation had a high incidence in PD patients.The composition and diversity of intestinal flora in fecal samples of PD patients changed compared with NC.2.The permeability of the colonic wall and the level of pα-syn expression of the colon mucosa increased in PD.3.The alterations of intestinal flora in PD are associated with degree of constipation,intestinal permeability,and expression of pα-syn in the colonic mucosa.