Session: 717 APS Wiggers Award: Sex and Aging in the Microcirculation Poster Session
(717.5) Macrophages Contribute to Sex Differences in Obesity-dependent Microvascular Dysfunction
Monday, April 4, 2022
10:15 AM – 12:15 PM
Location: Exhibit/Poster Hall A-B - Pennsylvania Convention Center
Poster Board Number: E122
Gean Domingos-Souza (Chicago Medical School, Rosalind Franklin University of Medicine and Science), James Hogan (Chicago Medical School, Rosalind Franklin University of Medicine and Science), Carl White (Chicago Medical School, Rosalind Franklin University of Medicine and Science)
Presenting Author Chicago Medical School, Rosalind Franklin University of Medicine and Science
Sex differences in obesity-induced microvascular dysfunction have been reported, however, the mechanisms are poorly understood. We previously identified macrophages as key cells that mediate microvascular dysfunction in obesity. Interestingly, sex differences in the inflammatory response to obesity have also been described. The current aim was to define the interaction between biological sex and macrophages on obesity-dependent microvascular dysfunction. We placed male and female mice (C57BL/6) on either a high-fat diet to induce obesity or a low-fat control diet. After twelve weeks mice were treated with either clodronate-containing liposomes to deplete macrophages or PBS-containing control liposomes. Macrophage depletion had no effect on body weight, glycemia, or mean arterial pressure, which were all increased by obesity in both male and female. Obesity also caused an expansion of the macrophage population in both male and female mesenteric perivascular adipose tissue, as quantified by flow cytometry, which was similarly attenuated by clodronate treatment. We then assessed microvascular function in third order mesenteric arterioles using pressure myography. The sensitivity of vasoconstriction to norepinephrine was increased by obesity in both male and female. Macrophage depletion dramatically attenuated vasoconstriction in male but only minimally affected vessels from females. In contrast, macrophage depletion had no effect on acetylcholine-dependent vasodilation in either male or female. Taken together, these data show that macrophages contribute to obesity-dependent microvascular hypercontractility in males but not females.