Perinatal asphyxia or hypoxia, where the infant brain does not receive enough oxygen or blood flow, commonly occurs in premature newborns and is one of the leading causes of neonatal mortality worldwide. Survivors often have altered white matter with cognitive impairments, motor deficits, and increased rates of cerebral palsy. There is currently no standard treatment for preterm brain injury, so there is a critical need to research neuroprotective strategies as well as ways to assess their impact. The ferret is a promising model species for studying preterm brain injury due to its gyrified brain and white-to-gray matter ratio, which are similar to that of the human brain. The gyrification index (GI) can be used to assess cortical development and is calculated using magnetic resonance imaging (MRI) images. These are analyzed using ImageJ software to perform hemispheric tracing by dividing an internal trace, including the gyri and sulci, by an external trace that excludes them. A higher GI is indicative of a larger cortical surface area. This project seeks to evaluate the effects of postnatal (P) age on post-hypoxic-ischemic (HI) gyrification in two ferret models. In both models, HI ferrets underwent bilateral carotid artery ligation and exposure to hypoxia, differing by date of surgery, with randomly assigned control animals not undergoing surgery. Model One ferrets underwent surgery at P10 (extremely preterm equivalent) and tissue collection at P70, and Model Two ferrets underwent surgery at P17 (late preterm equivalent) and tissue collection at P42. I hypothesize that GI will be affected by HI injury, with both age of injury and age of assessment altering GI relative to control animals. Contextualizing age differences in GI could help inform future therapy regimens to treat infants with premature brain injury.

Traumatic brain injury (TBI) is caused by an external force to the head, resulting in brain injury and is a major cause of death, particularly in adults 75 years and older who are at increased risk of falls which can lead to disability. Humans have a natural response to impact and strain called the Valsalva maneuver, which leads to an increased pressure in the chest and abdomen, which can result in a neuroprotective increase in intracranial pressure (ICP). However, most people are unable to anticipate TBIs and cannot perform their own Valsalva maneuver. Using a ferret model of TBI, the neuroprotective effects of externally-stimulated Valsalva-like response will be assessed. Ferrets are used to model human TBIs because the cortical thickness and layer distribution of their brains are more akin to humans in the ferret compared to rodents. The ferrets will be randomized to one of the three groups: control, TBI+sham valsalva, and TBI+valsalva. To show that the intracranial pressure of ferrets can be transiently increased, an inflatable cuff will be utilized to exert pressure on the abdomen, resulting in a partial Valsalva maneuver. TBI will be induced in the ferrets using a closed-head impact, and the neuroprotective effects of increased ICP from the inflatable abdominal cuff will be assessed using a battery of motor and cognitive tests before and after the TBI event, additionally, brain injury and neuroprotection will be evaluated using histopathology. I hypothesize that the Valsalva maneuver induced by the inflatable abdominal cuff will reduce behavioral deficits resulting from impact. If the behavioral deficits are reduced, this study can work to inform future interventions for TBI, such as environment-sensing wearable devices for high risk populations.

Preterm birth is one of the leading causes of infant morbidity and mortality worldwide, with a strong association between the degree of prematurity and the likelihood of death or neurodevelopmental impairment. Intracranial hemorrhage (ICH) is one of the most common neurological injuries for extremely preterm infants (born less than 28 weeks’ gestation). During the last trimester of pregnancy, neurons and glial cells develop in the germinal matrix requiring vast amounts of vascular support. In preterm infants, disturbances to blood and hydrostatic pressure are thought to rupture the immature vessels of the germinal matrix, leading to the bleeding in and around the ventricles. ICH is rated on a scale of I to IV, with severe ICH being grade III-IV. Mortality associated with ICH ranges from 30-60 percent, increasing with ICH severity, and survivors have an increased risk of cerebral palsy, seizures, and neurodevelopmental delay. From 2018-2020 the University of Washington (UW) neonatal intensive care unit (NICU) implemented an ICH Prevention Bundle, which focused on minimizing blood pressure disturbances during the first 72 hours after birth in infants born extremely premature, and appeared to result in a decrease in severe ICH. This study will evaluate the incidence rate of ICH at the UW NICU over a ten-year period. In a retrospective analysis of the UW NICU’s admissions, we will investigate extremely preterm infants born during the time periods of December 2013-September 2016 versus January 2017-December 2023 and record the incidence of ICH. Our primary outcomes will be ICH, by grades I-IV, as well as ICH complications such as posthemorrhagic ventricular dilatation with and without need for intervention, and death before discharge. We hypothesize that with improved prevention methods, such as the implementation of the ICH Prevention Bundle, we will see an associated long-term decrease in the incidence rate of ICH.