Human pharyngeal microbiota in age-related macular degeneration

Abstract

BackgroundWhile the aetiology of age-related macular degeneration (AMD)—a major blinding disease—remains unknown, the disease is strongly associated with variants in the complement factor H (CFH) gene. CFH variants also confer susceptibility to invasive infection with several bacterial colonizers of the nasopharyngeal mucosa. This shared susceptibility locus implicates complement deregulation as a common disease mechanism, and suggests the possibility that microbial interactions with host complement may trigger AMD. In this study, we address this possibility by testing the hypothesis that AMD is associated with specific microbial colonization of the human nasopharynx.ResultsHigh-throughput Illumina sequencing of the V3-V6 region of the microbial 16S ribosomal RNA gene was used to comprehensively and accurately describe the human pharyngeal microbiome, at genus level, in 245 AMD patients and 386 controls. Based on mean and differential microbial abundance analyses, we determined an overview of the pharyngeal microbiota, as well as candidate genera (Prevotella and Gemella) suggesting an association towards AMD health and disease conditions.ConclusionsUtilizing an extensive study population from Singapore, our results provided an accurate description of the pharyngeal microbiota profiles in AMD health and disease conditions. Through identification of candidate genera that are different between conditions, we provide preliminary evidence for the existence of microbial triggers for AMD.Ethical approval for this study was obtained through the Singapore Health Clinical Institutional Review Board, reference numbers R799/63/2010 and 2010/585/A.

Microbiome in the hair follicle of androgenetic alopecia patients

“…Follicular unit sample were subjected to bead beating (MP Biomedicals) and gDNA extraction using AllPrep RNA/DNA extraction kit following the manufacturer’s instructions (Qiagen). 16S rRNA PCR was performed on samples and duplicate template-free controls using primers spanning V3-V6 regions with PCR conditions described previously [36, 63]. DNA sequencing libraries were constructed with QIAseq FX DNA library kit (96) (Qiagen).…”

A pilot study to examine the association between human gut microbiota and the host's central obesity

“…A region on the 16S rRNA spanning the V3–V6 domains was amplified from total DNA as previously described . Amplicons were sheared using the Covaris LE220 sonicator (Covaris, Inc., USA) and built into sequencing libraries using GeneRead DNA Library I Core Kit (Qiagen) according to the manufacturer's protocol.…”

Local oral and nasal microbiome diversity in age-related macular degeneration

“…Considering the finding of characteristic pathogenic oral microbes in patients with newly diagnosed neovascular AMD, these bacteria may represent pathogenic species linked to promoting inflammation. Further, 16S rRNA of Gemella and Streptococcus are part of the pharyngeal microbiome recently described in late AMD patients as opposed to early AMD or controls 10 . Our report confirms the finding of Gemella and Streptococus as part of the nasal microbiome in newly diagnosed cases of neovascular AMD.…”

“…Ho, E. X. P. et al examined the pharyngeal microbiome in 245 AMD cases and 368 controls. Gemella was present in a higher abundance of AMD cases while Prevotella was reduced 10 .…”

“…Patients with the CFH gene risk variant also exposed to Chlamydia pneumonia (as measured by titres of antibodies against C. pneumonia) have been found to be at increased risk of AMD disease progression 8 . The role of microbes in AMD is in its infancy, but recent studies have shed light on particular gut and pharyngeal microbes present in patients with AMD, suggesting the diversity in microbial composition as a potential contributor to AMD pathophysiology 9,10 . To our knowledge, two studies have sought to characterize the microbiome in clinical cases of AMD.…”