A Biomarker for Predicting Responsiveness to Stem Cell Therapy Based on Mechanism-of-Action: Evidence from Cerebral Injury

Protocol to optimize the Rice-Vannucci rat pup model of perinatal asphyxia to ensure predictable hypoxic-ischemic cerebral lesions

“…Remark: Although the original RVM was developed in P7 rat pups, there has been variability in the field as to whether, in order to model perinatal asphyxia, the rats should be P7 or P10. We and others 2 have determined that P10, as used in this protocol and the accompanying Hartman paper, 1 more closely approximates the stage of brain development one sees in full-term human newborns, the target group for our translational project, for which this method was optimized. Place the anesthetized animal in supine position on the platform of a surgical stereo microscope and fix with adhesive tape across its belly and legs.…”

“… 3 , 4 As discussed below, this duration of hypoxia ensures an HII lesion with a significant penumbra that can respond to neuroprotective interventions. As described in Hartman et al., 1 the publication associated with this optimized protocol, a necrotic core is characterized by cells that start dying nearly immediately postinfarct from necrosis and, hence, are not amenable to neuroprotection. In other words, an animal model so severely injured that it contains only necrotic core with no salvageable penumbra is poorly suited for testing the efficacy of a neuroprotective therapy, whether it be pharmacological, genetic, cellular, or metabolic (e.g., hypothermia).…”

“…Note that here the volume of the penumbra is no smaller than that of the core, representing a significant expanse of brain that is amenable to neuroprotective interventions if instituted quickly (within 3–4 days post-HII, as per Hartman et al. 1 ). In comparison, an MRI scan from the same brain level in a sham-operated control animal (gray panel, c) is void of any signal indicating brain lesions.…”

“…HRS, which is based on the degree of restriction of water molecule diffusion in the brain, was used in Hartman et al. 1 to subdivide the HII lesion into, and calculate the volumes of, an irreversibly necrotic core (all cells already dead) vs. a penumbra which is characterized by damaged tissue that still contains surviving cells that typically progress to a delayed apoptotic cell death. HRS is described in greater detail in Ghosh et al.…”

Neonatal hyperoxia in mice triggers long-term cognitive deficits via impairments in cerebrovascular function and neurogenesis

“…Furthermore, NPC fate relies heavily on the surrounding cerebrovasculature ( 42 ). The effects of hypoxia on disrupting brain development in cases of apnea ( 43 ), hypoxia-ischemic injury ( 44 ), IVH ( 45 ), and PVL ( 46 ) are well established. However, little is known about the effects of hyperoxia on (a) the developing brain vasculature, (b) NPC function, and (c) cognitive performance.…”