Neuroprotection with an erythropoietin mimetic peptide (pHBSP) in a model of mild traumatic brain injury complicated by hemorrhagic shock

摘要

Pyroglutamate helix B surface peptide (pHBSP) is an 11 amino acid peptide, designed to interact with a novel cell surface receptor, composed of the classical erythropoietin (EPO) receptor disulfide linked to the beta common receptor. pHBSP has the cytoprotective effects of EPO without stimulating erythropoiesis. Effects on early cerebral hemodynamics and neurological outcome at 2 weeks post-injury were compared in a rat model of mild cortical impact injury (3m/sec, 2.5mm deformation) followed by 50min of hemorrhagic hypotension (MAP 40mm Hg for 50min). Rats were randomly assigned to receive 5000U/kg of EPO, 30μg/kg of pHBSP, or an inactive substance every 12h for 3 days, starting at the end of resuscitation from the hemorrhagic hypotension, which was 110min post-injury. Both treatments reduced contusion volume at 2 weeks post-injury, from 20.8±2.8mm 3 in the control groups to 7.7±2. 0mm 3 in the EPO-treated group and 5.9±1.5mm 3 in the pHBSP-treated group (p=0.001). Both agents improved recovery of cerebral blood flow in the injured brain following resuscitation, and resulted in more rapid recovery of performance on beam balancing and beam walking tests. These studies suggest that pHBSP has neuroprotective effects similar to EPO in this model of combined brain injury and hypotension. pHBSP may be more useful in the clinical situation because there is less risk of thrombotic adverse effects.