Neuroprotective effect of flavanol (-)-epicatechin after intracerebral hemorrhage Dietary polyphenols such as flavanols have been reported to help prevent diseases of the cardiovascular and central nervous systems. Cocoa and green tea are rich in flavanols, including (-)-epicatechin. A recent study from colleagues in our stroke group demonstrated that the flavanol (-)-epicatechin given orally reduces ischemic stroke damage through activation of Nrf2, a transcription factor that regulates the expression of endogenous antioxidant enzymes in the brain. We have demonstrated that mice lacking Nrf2 are more susceptible than wild-type control mice to brain damage from intracerebral hemorrhage (ICH). Additionally we showed that the exacerbation of brain injury in Nrf2 knockout mice was associated with increases in production of reactive oxygen species. The overall objective of this R01 is to address whether the flavanol (-)-epicatechin can be used as neuroprotective therapy in ICH, and if so, to generate preclinical efficacy data for its use and elucidate the underlying mechanisms. Our working hypothesis is that (-)-epicatechin reduces ICH injury through the Nrf2 pathway. We have designed three specific aims that utilize the collagenase-induced and autologous blood models of ICH. This research will be carried out in young and aged mice to enhance the clinical relevance.
Aim 1 will determine whether daily (-)-epicatechin treatment after ICH improves outcomes in young male mice.
Aim 2 will determine whether post-treatment with the optimal dose of (-)-epicatechin is effective in young female and aged mice.
Aim 3 will determine whether the Nrf2 pathway contributes to the neuroprotective effect of (-)- epicatechin in ICH models and in in vitro models of hemoglobin-induced toxicity. Through pharmacologic, genetic, imaging, histologic, molecular, and cellular biologic approaches, we will provide novel information about the efficacy of (-)-epicatechin in the two mouse ICH models and about the underlying mechanisms. Such information is required to plan more detailed preclinical trials and could influence clinical practices regarding flavanol use. Ultimately, the data may help the general public and healthcare providers make informed decisions on whether (-)-epicatechin could be accepted as an adjunct treatment in patients with ICH.
Dietary supplements such as flavanols are commonly used by the general public because they are thought to reduce the risk of certain diseases. The major goal of this proposal is to determine whether the flavanol (-)- epicatechin can reduce brain injury from intracerebral hemorrhage in two mouse models and to elucidate the underlying mechanisms. This work will provide the rationale for future clinical trials.
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