Macrophage-associated pro-inflammatory state in human islets from obese individuals.
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ABSTRACT: Obesity is associated with inflammatory macrophages in insulin responsive tissues and the resulting inflammatory response is a major contributor to insulin resistance. In insulin-producing pancreatic islets, the intra-islet accumulation of macrophages is observed in patients of type 2 diabetes (T2D), but such has not been investigated in obese individuals. Here, we show that pro-inflammatory cytokines (IL-1?, IL-6, and TNF), anti-inflammatory cytokines (IL-10 and TGF-?) and macrophage polarization markers (CD11c, CD163, and NOS2) were expressed in isolated human islets from non-diabetic donors. Clodronate-mediated depletion of resident macrophages revealed expression of IL1B and IL10 mostly from macrophages, while IL6, TNF, and TGFB1 came largely from a non-macrophage origin in human islets. NOS2 expression came exclusively from non-macrophage cells in non-obese individuals, while it originated also from macrophages in obese donors. Macrophage marker expression of CD68, CD163, and ITGAX was unchanged in islets of non-obese control and obese cohorts. In contrast, IL1B and NOS2 were significantly increased in islets from obese, compared to non-obese individuals, implying a more inflammatory macrophage phenotype in islets in obesity. Our study shows elevated macrophage-associated inflammation in human islets in obesity, which could be an initiating factor to the pro-inflammatory intra-islet milieu and contribute to the higher susceptibility to T2D in obese individuals.
SUBMITTER: He W
PROVIDER: S-EPMC6885511 | biostudies-literature | 2019 Dec
REPOSITORIES: biostudies-literature
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