Human blood vessel microbiota in healthy adults based on common femoral arteries of brain-dead multi-organ donors

Abstract

Discovery of human microbiota is fundamentally changing our perceptions of certain diseases and their treatments. However little is known about the human blood vessel microbiota, it may have important effects on vascular pathological lesions and vascular homograft failure. In our prospective survey study fourteen femoral arteries, harvested from donors in multi-organ donations, were examined using the V3-V4 region 16S rRNA sequencing method. The most abundant phyla in the human vascular microbiota were Proteobacteria, Firmicutes and Actinobacteria. At the genus level, the most abundant taxa were Staphylococcus, Corynebacterium, Pseudomonas, Bacillus, Acinetobacter and Propionibacterium. Of the bacterial taxa that have an indirect effect on the development of atherosclerosis, we found Porphyromonas gingivalis, Prevotella nigrescens and Enterobacteriaceae spp. with different abundances in our samples. Of the bacteria that are more common in the intestinal flora of healthy than of atherosclerosis patients, Roseburia and Ruminococcus occurred in the majority of samples. The human arterial wall has a unique microbiota that is significantly different in composition from that of other areas of the body. Our present study provides a basis for ensuing research that investigates the direct role of the microbiota in vascular wall abnormalities and the success of vascular allograft transplantations.

Characterizing the blood microbiota in healthy and febrile domestic cats via 16s rRNA sequencing

“…In accordance with research in dogs 28 , the healthy blood microbiota of cats in this study was dominated at the phylum level by Actinobacteria (median relative abundance 39.33%) and Firmicutes (32.02%), as opposed to previous research in cats where it was dominated by Bacteroidetes (67.60%) and Proteobacteria (22.26%). In humans, the most abundant phyla were Proteobacteria , Firmicutes , Actinobacteria , and Bacteroidetes 7 , 29 . One of the many possible explanations for this discrepancy is that previous research analyzed samples from just six healthy, lab raised kittens (< 8 months old) originating from just two litters on the same diet 15 .…”

The Diagnostic Potential of the Human Blood Microbiome: Are We Dreaming or Awake?

“…detected in human femoral arteries [9] (Table 2). Moreover, many indirect clues to bacterial presence in red blood cells of healthy donors' EVs suggest the presence of lipopolysaccharides (LPS) and outer membrane protein A (OmpA) [66].…”

“…Knowledge on the healthy blood microbiome is still an under-evaluated topic, even though many research groups focus on this issue. Results from these analyses converge on a microbiome dominated by Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes phyla ( Table 1 ) [ 9 , 25 ], with less abundant Fusobacteriota [ 26 , 27 ]. Some genera belonging to the phylum Firmicutes were identified in blood: Bacillus , obliged aerobic bacteria widespread in nature; [ 9 , 26 , 28 , 29 ] Lactobacillus, facultative anaerobic able to convert lactose and other sugars in lactic acid by lactic fermentation; Streptococcus , facultative anaerobic able to produce hemolytic exotoxins such as streptolysin; and Romboutsia [ 30 ], a gut species isolated in humans [ 31 ].…”

“…Results from these analyses converge on a microbiome dominated by Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes phyla ( Table 1 ) [ 9 , 25 ], with less abundant Fusobacteriota [ 26 , 27 ]. Some genera belonging to the phylum Firmicutes were identified in blood: Bacillus , obliged aerobic bacteria widespread in nature; [ 9 , 26 , 28 , 29 ] Lactobacillus, facultative anaerobic able to convert lactose and other sugars in lactic acid by lactic fermentation; Streptococcus , facultative anaerobic able to produce hemolytic exotoxins such as streptolysin; and Romboutsia [ 30 ], a gut species isolated in humans [ 31 ]. Moreover, the Actinobacteria genus Corynebacterium , commensal human bacteria usually not pathogenic in healthy state; Proteobacteria genus Pseudomonas , bacteria with great metabolic diversity able to colonize a wide range of niches [ 9 ]; and Bacteroides , a Bacteroidota genus associated with the gut microbiome, able to process complex polysaccharides into simpler ones were detected in healthy blood [ 30 , 32 ].…”

“…Moreover, the analysis of blood microbiome morphology in peripheral blood mononuclear cells (PBMCs) using light and electron microscopy highlighted how the blood microbiome displays a complex life cycle, undergoing different morphological transformations, such as vesiculation, tabulation, budding, irregular binary fission, and protrusion–extrusion of progeny cells from large electron-dense bodies [ 8 ]. Recently, several studies have managed to increase the “power” of analysis due to a lower abundance of bacterial DNA, investigating healthy blood microbial taxonomy, identifying the most abundant phyla, and sometimes also bacterial genera [ 9 ] using 16 s rRNA gene sequencing technology [ 10 , 11 ]. In some blood compartments (red/white blood cells, extracellular vesicles) specific bacteria were detected.…”