Human placental mesenchymal stem cells improve stroke outcomes via extracellular vesicles-mediated preservation of cerebral blood flow.

BACKGROUND: Besides long-term trans-differentiation into neural cells, benefits of stem cell therapy (SCT) in ischemic stroke may include secretion of protective factors, which partly reflects extracellular vesicle (EVs) released by stem cell. However, the mechanism(s) by which stem cells/EVs limit stroke injury have yet to be fully defined. METHODS: We evaluated the protection effect of human placenta mesenchymal stem cells (hPMSC) as a potential form of SCT in experimental ischemic stroke 'transient middle cerebral artery occusion (MCAO)/reperfusion' mice model. FINDINGS: We found for the first time that intraperitoneal administration of hPMSCs or intravenous hPMSC-derived EVs, given at the time of reperfusion, significantly protected the ipsilateral hemisphere from ischemic injury. This protection was associated with significant restoration of normal blood flow to the post-MCAO brain. More importantly, EVs derived from hPMSC promote paracrine-based protection of SCT in the MCAO model in a cholesterol/lipid-dependent manner. INTERPRETATION: Together, our results demonstrated beneficial effects of hPMSC/EVs in experimental stroke models which could permit the rapid "translation" of these cells into clinical trials in the near-term.

In Utero Exposure to Alcohol Impairs Reactivity of Cerebral Arterioles and Increases Susceptibility of the Brain to Damage Following Ischemia/Reperfusion in Adulthood.

BACKGROUND: Maternal consumption of alcohol produces abnormalities in the developing fetus and can contribute to an increased incidence of many cardiovascular-related diseases. The first goal of this study was to determine whether in utero exposure to alcohol influences reactivity of cerebral arterioles in adult (12 to 15 weeks old) rats. The second goal of this study was to examine whether in utero exposure to alcohol increased the susceptibility of the brain to damage following an ischemic event in adult rats. METHODS: We fed Sprague Dawley dams a liquid diet with or without alcohol (3% ethanol) for the duration of their pregnancy (21 to 23 days). In the first series of studies, we examined reactivity of cerebral arterioles to endothelial nitric oxide synthase (eNOS)- (adenosine diphosphate [ADP]) and neuronal nitric oxide synthase (nNOS)-dependent N-methyl-D-aspartate (NMDA, and NOS-independent agonists in adult rats before and during application of l-NMMA. In another series of studies, we examined infarct volume following middle cerebral artery occlusion in adult offspring exposed to alcohol in utero. In both series of studies, we also determined the role for an increase in oxidative stress by feeding dams apocynin for the duration of their pregnancy. RESULTS: We found that in utero exposure to alcohol reduced responses of cerebral arterioles to ADP and NMDA, but not to nitroglycerin in adult rats. In addition, treatment of the dams with apocynin prevented this impairment in cerebral vascular function. We also found that in utero exposure to alcohol worsened brain damage following ischemia/reperfusion in adult rats and that treatment of dams with apocynin prevented this increase in brain damage following ischemia/reperfusion. CONCLUSIONS: We suggest that our findings may have important implications for the pathogenesis of brain abnormalities associated with fetal alcohol exposure.

In utero exposure to alcohol alters reactivity of cerebral arterioles.

Our goal was to examine whether in utero exposure to alcohol impaired reactivity of cerebral arterioles during development. We fed Sprague-Dawley dams a liquid diet with or without alcohol (3% ethanol) for the duration of pregnancy (21-23 days). Around 4-6 weeks after birth, we examined reactivity of cerebral arterioles to eNOS- (ADP) and nNOS-dependent (NMDA) agonists in the offspring. We found that in utero exposure to alcohol attenuated responses of cerebral arterioles to ADP and NMDA, but not to nitroglycerin in rats exposed to alcohol in utero. L-NMMA reduced responses to agonists in control rats, but not in rats exposed to alcohol in utero. Treatment of dams with apocynin for the duration of pregnancy rescued the impairment in reactivity to ADP and NMDA in the offspring. Protein expression of NOX-2 and NOX-4 was increased in alcohol rats compared to control rats. We also found an increase in superoxide levels in the cortex of rats exposed to alcohol in utero. Our findings suggest that in utero exposure to alcohol impairs eNOS and nNOS reactivity of cerebral arterioles via a chronic increase in oxidative stress.

Severe respiratory changes at end stage in a FUS-induced disease state in adult rats.

BACKGROUND: Fused in sarcoma (FUS) is an RNA-binding protein associated with the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration. ALS manifests in patients as a progressive paralysis which leads to respiratory dysfunction and failure, the primary cause of death in ALS. We expressed human FUS in rats to determine if FUS would induce ALS relevant respiratory changes to serve as an early stage disease indicator. The FUS expression was initiated in adult rats by way of an intravenously administered adeno-associated virus vector serotype 9 (AAV9) providing an adult onset model. RESULTS: The rats developed progressive motor impairments observed as early as 2-3 weeks post gene transfer. Respiratory abnormalities manifested 4-7 weeks post gene transfer including increased respiratory frequency and decreased tidal volume. Rats with breathing abnormalities also had arterial blood acidosis. Similar detailed plethysmographic changes were found in adult rats injected with AAV9 TDP-43. FUS gene transfer to adult rats yielded a consistent pre-clinical model with relevant motor paralysis in the early to middle stages and respiratory dysfunction at the end stage. Both FUS and TDP-43 yielded a similar consistent disease state. CONCLUSIONS: This modeling method yields disease relevant motor and respiratory changes in adult rats. The reproducibility of the data supports the use of this method to study other disease related genes and their combinations as well as a platform for disease modifying interventional strategies.