Renal perivascular adipose tissue: Form and function

Abstract

Renal sympathetic activity affects blood pressure in part by increasing renovascular resistance via release of norepinephrine (NE) from sympathetic nerves onto renal arteries. Here we test the idea that adipose tissue adjacent to renal blood vessels, i.e. renal perivascular adipose tissue (RPVAT), contains a pool of NE which can be released to alter renal vascular function. RPVAT was obtained from around the main renal artery/vein of the male Sprague Dawley rats. Thoracic aortic PVAT and mesenteric PVAT also were studied as brown-like and white fat comparators respectively. RPVAT was identified as a mix of white and brown adipocytes, because of expression of both brown-like (e.g. uncoupling protein 1) and white adipogenic genes. All PVATs contained NE (ng/g tissue, RPVAT:524 ± 68, TAPVAT:740 ± 16, MPVAT:96 ± 24). NE was visualized specifically in RPVAT adipocytes by immunohistochemistry. The presence of RPVAT (+RPVAT) did not alter the response of isolated renal arteries to NE compared to responses of arteries without RPVAT (-RPVAT). By contrast, the maximum contraction to the sympathomimetic tyramine was ~2× greater in the renal artery +PVAT versus -PVAT. Tyramine-induced contraction in +RPVAT renal arteries was reduced by the α-adrenoceptor antagonist prazosin and the NE transporter inhibitor nisoxetine. These results suggest that tyramine caused release of NE from RPVAT. Renal denervation significantly (>50%) reduced NE content of RPVAT but did not modify tyramine-induced contraction of +RPVAT renal arteries. Collectively, these data support the existence of a releasable pool of NE in RPVAT that is independent of renal sympathetic innervation and has the potential to change renal arterial function.

Renal sinus fat and renal hemodynamics: a cross-sectional analysis

“…Second, by compressing various renal 1 3 structures, reduced tissue perfusion and tubular flow may occur [8]. Third, in analogy to adipocytes from perivascular adipose tissue (PVAT), RSF adipocytes may secrete proinflammatory adipokines leading to renal inflammation, fibrosis and dysfunction [7,14,15]. Fourth, RSF could modulate renal hemodynamics by secreting vasoconstrictive factors, as several studies have demonstrated PVAT to modulate vascular tone and skeletal muscle perfusion [16].…”

Uterine perivascular adipose tissue is a novel mediator of uterine artery blood flow and reactivity in rat pregnancy

“…; Restini et al . ), although they become pro‐contractile in obesity (Owen et al . ; Fernandez‐Alfonso et al .…”

Perivascular adipose tissue in cardiovascular diseases – an update

“…However, electron microscopy reveals numerous lipid inclusions and mitochondria in tPVAT, resembling brown adipocytes. The molecular phenotype of tPVAT involves the Ucp-1, CIDE-A, and PRDM16 positivity, along with the TCF-1 negativity, in a similar manner to that of BAT (5,11). In contrast, aPVAT adipocytes have a phenotype similar to WAT cells (5,12), expressing a spectrum of genes codifying characteristic markers such as adiponectin, resistin, lipoprotein lipase (LPL), and glyceraldehyde 3-phosphate dehydrogenase (G3PDH) (7,11,12).…”

“…They produce NO, adiponectin, semicarbazide-sensitive amine oxidase (SSAO), or H 2 S, resulting in a protective role of the entire mesenteric bed (14). In murine models, they intensely express white adipocytes genes, such as TCF-1, Adipoq, and C/EBPα (11).…”