Presence and Variability of the Microbiome in Perivascular Adipose Tissue: A Whole-Genome Sequencing Study in Dahl SS Rats

Background. Perivascular adipose tissue (PVAT) contains adipocytes and a stromal-vascular fraction with immune cells that modulate the adjacent vasculature. The presence of immune cells in PVAT of vascular beds is poorly understood—are they resident or recruited? We propose a novel resident microbiome is present in PVAT, given the immune-rich stromal environment. Hypothesis. We hypothesized the existence of distinct bacterial and viral communities in healthy PVAT compared to non-PVAT adipose tissues. Methods. PVAT samples from thoracic and abdominal aorta, mesenteric resistance arteries, non-PVAT tissues (subscapular brown adipose tissue, retroperitoneal white adipose tissue), and fecal samples were collected one year apart from male Dahl SS rats, split into two cohorts (2023 and 2024, n=3 each). Whole-genome shotgun sequencing (CosmosID) and 16S rRNA gene analysis assessed microbial relative abundance. Results. PVAT harbored bacterial and viral sequences, and species composition varied significantly between cohorts. Bacterial and viral fecal samples showed lower variability. Conclusions. This confirms a microbiome in PVAT that differed dramatically from the fecal microbiome, with temporal influences on bacterial and viral diversity, marking the first such report. These findings establish the potential of PVAT microbiota in vascular biology and immune modulation, paving the development of microbiome-targeted drugs to address vascular dysfunctions.