The discovery of the expression of erythropoietin receptor (EPOR) in the central nervous system (CNS) has led to a surge in research related to neuroprotection by erythropoietin (EPO), in addition to its well-known hematopoietic properties. EPO induces neuroprotective effects in the CNS through, for example, inhibition of apoptosis in neurons and cerebrovasculature, and it also improves tissue oxygenation through the promotion of angiogenesis and induction of erythroid cell differentiation. Treatment with recombinant human (rh) EPO was also associated with an improvement in follow-up and outcome scales and a strong trend for reduction in infarct size in patients with ischemic stroke. However, rhEPO has only limited ability to cross the blood-brain barrier (BBB), and therefore, the concentrations of rhEPO in the central nervous system are far lower than in circulation. Low molecular weight EPO mimetics were recently described with in vitro neuroprotective and in vivo hematopoietic activities, but improvements in potency, pharmacokinetics, and drug properties for CNS activity are required for optimal in vivo efficacy for neuroprotection. The objective of this research program is to identify additional small molecule EPO mimetic compounds and to perform initial analysis of structure-activity relationships. Moreover, this program aims to analyze these compounds for their neuroprotective activities and pharmacokinetics for CNS penetrance. The overall goal is to one day develop these compounds for ischemic stroke, because rhEPO has demonstrated clinical proof-of-concept in this indication, and the improved physical and functional properties of the proposed low molecular weight EPO mimetics would provide significant benefits for these patients when compared to treatment with rhEPO. Novel EPO mimetics from this approach are expected to demonstrate improved BBB permeability, while at the same time providing the convenience and safety of once-daily oral dosing and a lack of immunogenicity, a risk associated with rhEPO. Stroke represents a major unmet medical need and the economic burden of stroke in the United States alone has been estimated in the trillions of dollars.
The objective of the proposed studies is to identify and characterize drug-like low molecular weight erythropoietin mimetics to provide candidate new therapies for ischemic stroke. The compounds derived from the proposed studies have the potential to improve the therapeutic approaches in stroke patients, as well as in other diseases of the central nervous system when neuroprotective effects are desired. ? ? ?
