Oral Microbiome Stamp in Alzheimer's Disease.

Recent studies have suggested that periodontal disease and alterations in the oral microbiome may be associated with cognitive decline and Alzheimer's disease (AD) development. Here, we report a case-control study of oral microbiota diversity in AD patients compared to healthy seniors from Central Asia. We have characterized the bacterial taxonomic composition of the oral microbiome from AD patients (n = 64) compared to the healthy group (n = 71) using 16S ribosomal RNA sequencing. According to our results, the oral microbiome of AD has a higher microbial diversity, with an increase in Firmicutes and a decrease in Bacteroidetes in the AD group. LEfSe analysis showed specific differences at the genus level in both study groups. A region-based analysis of the oral microbiome compartment in AD was also performed, and specific differences were identified, along with the absence of differences in bacterial richness and on the functional side. Noteworthy findings demonstrated the decrease in periodontitis-associated bacteria in the AD group. Distinct differences were revealed in the distribution of metabolic pathways between the two study groups. Our study confirms that the oral microbiome is altered in AD. However, a comprehensive picture of the complete composition of the oral microbiome in patients with AD requires further investigation.

Oral Microbial Signature of Rheumatoid Arthritis in Female Patients.

This study aimed to identify the oral microbial signature of Kazakh female rheumatoid arthritis (RA) patients. A total of 75 female patients who met the American College of Rheumatology 2010 classification criteria for RA and 114 healthy volunteers were included in the study. Amplicons of the 16S rRNA gene were sequenced to analyze the microbial composition. We identified significant differences in bacterial diversity and abundance between the RA and control groups, as measured by Shannon (p value = 0.0205) and Simpson (p value = 0.00152) indices. The oral samples from RA patients had higher bacterial diversity than those from non-RA volunteers. The RA samples had a higher relative abundance of Prevotellaceae and Leptotrichiaceae, but a lower content of butyrate and propionate-producing bacteria compared to the control group. The samples from patients in remission had a higher abundance of Treponema sp. and Absconditabacteriales (SR1), whereas those with low disease activity had higher levels of Porphyromonas and those with high RA activity had higher levels of Staphylococcus. A positive correlation was found between the taxa Prevotella_9 and serum levels of antibodies to cyclic citrullinated peptide (ACPA) and rheumatoid factor (RF). The predicted functional pattern of the ACPA+/RF- and ACPA+/RF+ seropositive groups was characterized by increased ascorbate metabolism, degradation of glycosaminoglycans, and reduced biodegradation of xenobiotics. These findings suggest that the functional pattern of the microflora should be considered when selecting a therapeutic strategy for RA in order to provide a personalized approach.

Association Study of Anticitrullinated Peptide Antibody Status with Clinical Manifestations and SNPs in Patients Affected with Rheumatoid Arthritis: A Pilot Study.

Introduction: Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology that leads to disability due to articular and extra-articular damage. RA prevalence is variable. The disease is most common among females with a 3 : 1 ratio. The interaction of environmental and host factors contributes to RA development. Currently, the genome-wide association studies (GWAS) give the opportunity to uncover the RA genetic background. Anticitrullinated peptide antibody (ACPA) is a highly specific RA antibody, associated with poor prognosis and severe course of RA, and regulated by numerous genes. Our study is aimed at investigating whether there are any clinical and genetic aspects correlate with ACPA presence in Kazakhstani patients with RA. Indeed, the available studies on this subject are focused on Caucasian and East Asian populations (mainly Japanese and Chinese), and there are scarce data from Central Asia. Methods: Our study included 70 RA patients. Patients' blood samples were collected and genotyped for 14 SNPs by real-time polymerase chain reaction (RT-PCR). General examination, anamnestic, and clinical and laboratory data collection were carried out. Statistical analysis was performed using R statistics. Results and Conclusion. Our study revealed a significant association of ACPA positivity with Fc receptor-like 3 (FCRL3) and ACPA negativity with signal transducer and activator of transcription 4 (STAT4) genes, but not with T cell activation Rho GTPase activating protein (TAGAP). In addition, ACPA positivity was associated with radiographic progression, rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), age of RA onset, the patient global assessment, body mass index (BMI), and Gamma globulin. Conclusion: Remained 11 earlier identified significantly associated in Caucasian and Asian population SNPs were not replicated in our cohort. Further studies on larger cohorts are needed to confirm our findings with higher confidence levels and stronger statistical power.