Shen L, Dashwood MR, Casale C, Orie NN, Evans IM, Sufi P, Gray R, Mohamed-Ali V. Depot- and diabetes-specific differences in norepinephrine-mediated adipose tissue angiogenesis, vascular tone, collagen deposition and morphology in obesity.
Life Sci 2022;
305:120756. [PMID:
35780713 DOI:
10.1016/j.lfs.2022.120756]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/18/2022] [Accepted: 06/27/2022] [Indexed: 11/17/2022]
Abstract
AIMS
Norepinephrine (NE) is a known regulator of adipose tissue (AT) metabolism, angiogenesis, vasoconstriction and fibrosis. This may be through autocrine/paracrine effects on local resistance vessel function and morphology. The aims of this study were to investigate, in human subcutaneous and omental adipose tissue (SAT and OAT): NE synthesis, angiogenesis, NE-mediated arteriolar vasoconstriction, the induction of collagen gene expression and its deposition in non-diabetic versus diabetic obese subjects.
MATERIALS AND METHODS
SAT and OAT from obese patients were used to investigate tissue NE content, tyrosine hydroxylase (TH) density, angiogenesis including capillary density, angiogenic capacity and angiogenic gene expression, NE-mediated arteriolar vasoconstriction and collagen deposition.
KEY FINDINGS
In the non-diabetic group, NE concentration, TH immunoreactivity, angiogenesis and maximal vasoconstriction were significantly higher in OAT compared to SAT (p < 0.05). However, arterioles from OAT showed lower NE sensitivity compared to SAT (10-8 M to 10-7.5 M, p < 0.05). A depot-specific difference in collagen deposition was also observed, being greater in OAT than SAT. In the diabetic group, no significant depot-specific differences were seen in NE synthesis, angiogenesis, vasoconstriction or collagen deposition. SAT arterioles showed significantly lower sensitivity to NE (10-8 M to 10-7.5 M, p < 0.05) compared to the non-diabetic group.
SIGNIFICANCE
SAT depot in non-diabetic obese patients exhibited relatively low NE synthesis, angiogenesis, tissue fibrosis and high vasoreactivity, due to preserved NE sensitivity. The local NE synthesis in OAT and diabetes desensitizes NE-induced vasoconstriction, and may also explain the greater tissue angiogenesis and fibrosis in these depots.
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