Small Vessels-Big Problems : Novel Insights into Microvascular Mechanisms of Diseases PGE 2-EP 3 signaling exacerbates intracerebral hemorrhage outcomes in 24-mo-old mice

Leclerc JL, Lampert AS, Diller MA, Doré S. PGE2-EP3 signaling exacerbates intracerebral hemorrhage outcomes in 24-mo-old mice. Am J Physiol Heart Circ Physiol 310: H1725–H1734, 2016. First published April 15, 2016; doi:10.1152/ajpheart.00638.2015.— With the population aging at an accelerated rate, the prevalence of stroke and financial burden of stroke-related health care costs are expected to continue to increase. Intracerebral hemorrhage (ICH) is a devastating stroke subtype more commonly affecting the elderly population, who display increased mortality and worse functional outcomes compared with younger patients. This study aimed to investigate the contribution of the prostaglandin E2 (PGE2) E prostanoid (EP) receptor subtype 3 in modulating anatomical outcomes and functional recovery following ICH in 24-mo-old mice. EP3 is the most abundant EP receptor in the brain and we have previously shown that signaling through the PGE2-EP3 axis exacerbates ICH outcomes in young mice. Here, we show that EP3 receptor deletion results in 17.9 6.1% less ICH-induced brain injury (P 0.05) and improves neurological functional recovery (P 0.01), as identified by lower neurological deficit scores, decreased resting time, and more gross and fine motor movements. Immunohistological staining was performed to investigate possible mechanisms of EP3-mediated neurotoxicity. Identified mechanisms include reduced blood accumulation and modulation of angiogenic and astroglial responses. Using this aged cohort of mice, we have confirmed and extended our previous results in young mice demonstrating the deleterious role of the PGE2-EP3 signaling axis in modulating brain injury and functional recovery after ICH, further supporting the notion of the EP3 receptor as a putative therapeutic avenue for the treatment of ICH.