Abstract 57: Histone Deacetylase Inhibition Attenuates Early Life Stress-Induced Endothelial Dysfunction

Abstract

Epidemiological studies show that early life stress (ELS) is linked to cardiovascular disease in adulthood. We used a model of maternal separation with early weaning (MSEW) to study the mechanisms of ELS-mediated adult vascular dysfunction in male C57BL/6J mice. MSEW litters were subjected to maternal separation 4h/day (postnatal day (PD) 2 to 5) and 8h/day (PD6 to 16), and weaned at PD17. Control (CON) litters were undisturbed until weaning at PD21. All subsequent experiments were performed in adult mice (12 weeks old). We hypothesized that MSEW increases vascular inflammation and endothelial dysfunction in male mice. Systolic blood pressure (tail-cuff) of MSEW mice was not different from CON mice (109.3 + 10.9 vs 116.7 + 20.8 mmHg, respectively). Circulating soluble intercellular adhesion molecule (CON: 333.5 + 19.4 vs MSEW: 406.2 + 23.1 ng/ml; p = 0.03) and macrophage colony stimulating factor (CON: 737.4 + 19.6 vs MSEW: 945.3 + 65.4 pg/ml; p = 0.01) were elevated by MSEW. Also, aortic adventitial macrophage infiltration was increased in mice exposed to MSEW (F4/80 immunostaining; CON: 2.8 + 2.3 vs MSEW: 7.0 + 2.2 cells/mm 2 ; p = 0.05). We performed wire myography on thoracic aortae to determine vasorelaxation with cumulative concentration-response curve to acetylcholine (ACh; 1 X 10 -9 M to 3 X 10 -5 M) and sodium nitroprusside (SNP; 1 X 10 -10 M to 3 X 10 -5 M). MSEW induced blunted ACh-mediated vasorelaxation (MSEW: 67.6 + 5.8 vs CON: 89.9 + 2.7 % of phenylephrine constriction (% of PE), p = 0.01), while SNP-induced vasorelaxation was similar in CON and MSEW mice. We further hypothesized that MSEW-induced endothelial dysfunction is mediated via increased histone deacetylase (HDAC) expression. Real-time quantitative PCR revealed upregulation of HDAC 1, 6 and 9 in aortae of MSEW mice (1.28 + 0.12, 1.28 + 0.18 and 1.65 + 0.05 fold change from CON, respectively, p < 0.05). Pretreatment with trichostatin A (TSA), an HDAC inhibitor, normalized ACh-induced vasorelaxation in aortae of MSEW mice (MSEW: 67.6 + 5.8 vs MSEW + TSA: 88.44 + 3.2 % of PE, p = 0.02), while not affecting ACh-induced vasorelaxation in aortae from CON mice (CON: 89.9 + 2.7 vs CON + TSA: 90.3 + 4.5 % of PE). We conclude that ELS induces blood pressure-independent endothelial dysfunction through an HDAC-mediated pathway.