Summary
Spinal cord injury (SCI) is characterized by secondary degeneration, which leads to tissue loss at the epicenter and subsequent functional deficits. This review provides insight into the pathophysiology of microvascular dysfunction and endothelial cell loss, which are among the earliest responses during the first postinjury day. The enigmatic role of the angiogenic response in the penumbra around the lost tissue, which occurs during the first 2 weeks, is also discussed. The importance of stabilizing and rescuing the injured vasculature is now well-recognized, and several pharmacological and genetic treatments have emerged in the past few years. We conclude with suggestions for future experimental research, including development of vascular-selective treatments and exploitation of genetic models. In summary, vascular dysfunction following SCI is an important contributor to neurological deficits, as proposed long ago. However, there now appears to be new and potentially powerful opportunities for treating acute SCI by targeting the vascular responses.
Treatment with tPA improves the functional and anatomical outcomes in patients with thick subfoveal hemorrhage due to subfoveal choroidal neovascular membrane secondary to exudative age-related macular degeneration and was superior to PD without tPA. Vitrectomy with subretinal tPA injection reduced the final disciform scar compared with PD with or without intravitreal tPA.
Trauma introduces damaging stressors that compromise protein, lipid, and nucleic acid integrity. Aggregates of unfolded and misfolded proteins in the endoplasmic reticulum (ER) triggers the ER stress response (ERSR)/unfolded protein response (UPR) leading to activation of three signaling pathways mediated by PERK, ATF6, and IRE1. Initially, the ERSR/UPR is pro-homeostatic as it globally slows translation while increasing translation of chaperone proteins and inducing ER-associated degradation. If the cellular stress is not controlled, apoptosis is subsequently induced through several mechanisms, of which the most well-described is CHOP. Following spinal cord injury (SCI), mice deficient in CHOP signaling show increased spared white matter and enhanced locomotor recovery by 6 weeks. At 24 hours after SCI, ATF4 and CHOP are upregulated in under perfused microvessels. We observed vascular protection 3 days post-SCI and a significant decrease in macrophage infiltration by the end of the first week. These results suggest that modulating ER-stress signaling in endothelial cells and macrophages may protect against vascular injury and attenuate inflammation post-SCI.
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