Early life stress (ELS) induces aortic stiffening and increased cytokine production in mice

Abstract

ELS exposure (childhood adversity such as household dysfunction, abuse, or neglect) is an independent risk factor for adult-onset cardiovascular disease (CVD). ELS exposure is associated with increased circulating inflammatory markers in humans, as well as elevated aortic inflammatory monocytes in mice. The cellular sources and mechanisms of excessive cytokine production behind these findings are still poorly understood. We hypothesized that mice exposed to ELS, maternal separation with early weaning (MSEW), will have greater arterial stiffening and greater reactive aortic macrophages leading to a larger cytokine response when activated with LPS than normally reared (NR) mice. The MSEW model includes pups separated from the dam 4h/day (postnatal day (PD) 2 to PD5), 8h/day (PD6 to 16), and weaned at PD17. NR pups remain with the dams until weaning at PD21. Pulse wave velocity (PWV), a measure of aortic stiffness, determined at 6 wks of age found that MSEW mice had elevated PWV as compared to NR (NR: 1.2±0.08 mm/sec, MSEW: 2.1±0.04 mm/sec, p<0.0001, n=4,6). In the aorta, total F4/80+ macrophages as well as cells expressing activation markers CD86 and MHCII were elevated in 14 wk old MSEW mice (%F4/80+: NR:2.73±0.34, MSEW 5.04±0.56, p=0.004, n=7,5; %CD86: NR: 0.12±0.03, MSEW: 0.52±0.09, p=0.004, n=7,5; %MHCII: NR: 1.14±0.09, MSEW: 1.92±0.22, p=0.001, n=7,5). MSEW mice showed significantly elevated levels of macrophages (%CD11c-CD11b+F4/80+ of CD45+) in the spleen red pulp (NR: 1.09±0.04, MSEW: 1.28±0.07, P=0.03, n=14,10). However, expression of activation markers CD86 and MHCII as well as TNFα, IL-1b and IL6 in splenic macrophages from 14 wk old MSEW mice did not significantly differ between the MSEW and NR cohorts. Finally, we isolated splenic macrophages, stimulated with LPS (100 ng/mL) for 24 hrs and cytokine secretion measured by cytokine array. The qualitative array showed that the total supernatant of macrophage cultures from MSEW sample had greater IL1-ra, IL-16, G-CSF, CXCL10, macrophage inflammatory protein 1B and 2, and TNFα compared to cultures from NR samples. These results suggest that macrophages of MSEW mice are primed for inflammatory responses and may secrete intracellular cytokines compared to macrophages from NR mice. Elevated PWV is an early indicator for the development of CVD, seen as early as 6 wks in MSEW mice. Taken together these findings suggest a greater propensity for those who have experienced ELS to develop CVD. Future studies will aim to elucidate the role of the elevated macrophage derived cytokines in arterial stiffening. NIH R25 DK 112731, NIH R25 DK 115353, NIH T32 DK 116672 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.