Acute or Delayed Systemic Administration of Human Amnion Epithelial Cells Improves Outcomes in Experimental Stroke.

BACKGROUND AND PURPOSE: Human amnion epithelial cells (hAECs) are nonimmunogenic, nontumorigenic, anti-inflammatory cells normally discarded with placental tissue. We reasoned that their profile of biological features, wide availability, and the lack of ethical barriers to their use could make these cells useful as a therapy in ischemic stroke. METHODS: We tested the efficacy of acute (1.5 hours) or delayed (1-3 days) poststroke intravenous injection of hAECs in 4 established animal models of cerebral ischemia. Animals included young (7-14 weeks) and aged mice (20-22 months) of both sexes, as well as adult marmosets of either sex. RESULTS: We found that hAECs administered 1.5 hours after stroke in mice migrated to the ischemic brain via a CXC chemokine receptor type 4-dependent mechanism and reduced brain inflammation, infarct development, and functional deficits. Furthermore, if hAECs administration was delayed until 1 or 3 days poststroke, long-term functional recovery was still augmented in young and aged mice of both sexes. We also showed proof-of-principle evidence in marmosets that acute intravenous injection of hAECs prevented infarct development from day 1 to day 10 after stroke. CONCLUSIONS: Systemic poststroke administration of hAECs elicits marked neuroprotection and facilitates mechanisms of repair and recovery.

Sex-dependent effects of G protein-coupled estrogen receptor activity on outcome after ischemic stroke.

BACKGROUND AND PURPOSE: Experimental studies indicate that estrogen typically, but not universally, has a neuroprotective effect in stroke. Ischemic stroke increases membrane-bound G protein-coupled estrogen receptor (GPER) distribution and expression in the brain of male but not female mice. We hypothesized that GPER activation may have a greater neuroprotective effect in males than in females after stroke. METHODS: Vehicle (dimethyl sulfoxide), a GPER agonist (G-1, 30 µg/kg), or a GPER antagonist (G-15, 300 µg/kg) were administered alone or in combination to young or aged male mice, or young intact or ovariectomized female mice, 1 hour before or 3 hours after cerebral ischemia-reperfusion. Some mice were treated with a combination of G-1 and the pan-caspase inhibitor, quinoline-Val-Asp(Ome)-CH2-O-phenoxy (Q-VD-OPh), 1 hour before stroke. We evaluated functional and histological end points of stroke outcome up to 72 hours after ischemia-reperfusion. In addition, apoptosis was examined using cleaved caspase-3 immunohistochemistry. RESULTS: Surprisingly, G-1 worsened functional outcomes and increased infarct volume in males poststroke, in association with an increased expression of cleaved caspase-3 in peri-infarct neurons. These effects were blocked by G-15 or Q-VD-OPh. Conversely, G-15 improved functional outcomes and reduced infarct volume after stroke in males, whether given before or after stroke. In contrast to findings in males, G-1 reduced neurological deficit, apoptosis, and infarct volume in ovariectomized females, but had no significant effect in intact females. CONCLUSIONS: Future therapies for acute stroke could exploit the modulation of GPER activity in a sex-specific manner.

Stroke increases g protein-coupled estrogen receptor expression in the brain of male but not female mice.

The novel estrogen receptor, G protein-coupled estrogen receptor (GPER, previously named GPR30), is widely distributed throughout the male and female brain and, thus, could potentially play a role in estrogen-mediated neuroprotective effects in diseases such as stroke. We hypothesized that GPER distribution and expression in the brain of male, intact female, and ovariectomized (OVX) mice is increased after 0.5 h middle cerebral artery occlusion. Using immunohistochemistry, we found that ischemia reperfusion increased GPER distribution in the peri-infarct brain regions of male mice, but surprisingly not in intact females or OVX mice. Similar differences were observed in the male and female human brain after stroke. In contrast, GPER distribution was decreased in the infarct core of all mice examined. Furthermore, GPER immunofluorescence was co-localized with the endothelial cell marker, von Willebrand factor, and the neuronal marker, NeuN. Consistent with the immunohistochemical findings, Western blot analysis showed GPER expression is only elevated in the ischemic hemisphere of male mice. Moreover, GPER mRNA expression in males was elevated at 4 h but had returned to baseline by 24 h. In conclusion, these findings indicate that GPER may be a potential therapeutic target after stroke, especially in males, in whom estrogen therapy is not feasible.