Direct Hyperbilirubinemia in Infants with Trisomy 13 and 18

Background: Survival in trisomy 13 (T13) and 18 (T18) has increased in recent years, but little is known about the prevalence and management of the non-lethal complications in these populations. Significance of Problem: A subjectively high rate of direct hyperbilirubinemia (DH) was noted at Children’s Hospital & Medical Center compared to the general population. Defining the prevalence, timing, and risk factors for DH will allow for the development of screening and management guidelines. Hypothesis, Problem or Question: We hypothesized that infants with T13 and T18 would have high rates of DH, with no significant difference in prevalence between the two populations. Experimental Design: Retrospective cohort study of infants born between Jan 1, 2012 and March 1, 2020 and admitted to the NICU at Children’s or the Nebraska Medical Center within the first month of life. Data collected included bilirubin, ALT, AST, and GGT levels, liver imaging, and any treatment administered. DH is defined as conjugated bilirubin \u3e1 mg/dL, but the cutoff of \u3e2 mg/dL has a higher association with underlying pathology. Fisher’s exact test and Mann-Whitney U test were used for categorical and continuous variables in DH for both cutoffs. Results/Data: Thirty-five patients met inclusion criteria: 13 with T13 and 22 with T18. When using the \u3e1 mg/dL cutoff, DH was seen in 7/13 (53.8%) patients with T13 and 9/22 (40.9%) with T18, which was not significantly different between the two diagnoses. Twelve of the 16 infants with DH developed DH in the first two weeks of life and, although it did not reach significance, patients with T13 tended to present with DH earlier than those with T18 (median 5 vs. 12 days of life). DH occurred more often in infants who received TPN (81.3 vs. 36.8%, p=0.016). DH was associated with higher peak AST (p=0.004), ALT (p=0.002), but not GGT (p=0.176) levels. The presence of an abnormal ultrasound was not associated with DH. Six infants were treated with phenobarbital or ursodiol, and 5/6 normalized their conjugated bilirubin levels within one week of starting therapy. Conclusions: DH was common in infants with T13 and T18, and at a qualitatively higher prevalence than what has previously been reported in the general population, even if excluding those infants who received TPN. Clinicians should consider screening for DH starting within the first week of life in both trisomy 13 and 18, continuing weekly if \u3c1 mg/dL until discharge from hospital.https://digitalcommons.unmc.edu/chri_forum/1011/thumbnail.jp

Identifying Risk Factors for Significant Hyponatremia during Vasopressin Administration in Neonates

https://digitalcommons.unmc.edu/surp2023/1011/thumbnail.jp

Relationship between miR-335 and sterol levels after in vitro hypoxia-ischemia of primary brain cells

Background/Purpose: Cholesterol homeostasis is vital for synaptogenesis and myelination during fetal and neonatal brain development. Both brain and plasma sterol levels have been shown to be associated with outcomes in adult stroke, and animal studies have suggested brain and plasma sterol changes in neonatal hypoxic-ischemic brain injury. MicroRNA-335 (miR-335) has been associated with brain sterol metabolism and our preliminary data showed that sterol metabolism is dysregulated in the brain after hypoxic-ischemic injury in a mouse model. This study sought to describe the effect of oxygen-glucose deprivation in vitro on individual brain cell populations and to validate the associations between sterol levels and miR-335 levels. Lastly, we assessed the feasibility of transfecting miR-335 mimics or miRNA antagonists (antagomiRs) in these brain cell cultures to set up future experiments to alter miR-335 levels for neuroprotection. Methods: Primary cells were isolated from embryonic day 18 CD1 mouse brains. Cells were maintained in DMEM for mixed glial culture and Neurobasal media with B27 for neurons. Once astrocytes were confluent, microglia were separated from the mixed glial culture by shaking to provide pure cell populations. Each of the three cell types underwent oxygen and glucose deprivation (OGD: glucose/pyruvate/B27-free media, 1% O2, 5% CO2) for 4 hours followed by replacement of glucose/pyruvate/B27 and resumption of normoxia. At 24 hours after OGD, cells (n=12 wells OGD and 12 normoxia) were washed, counted, and sterols analyzed by LC-MS/MS, normalized to the number of cells/well. Additional cells underwent measurement of miR-335 expression using quantitative PCR and/or transfection with miR-335 mimic or antagomiR. Results: Although lanosterol is increased after OGD in neurons, desmosterol and cholesterol levels were decreased. In microglia and astrocytes, cholesterol levels were lower than in neurons but increased after OGD. MiR-335 expression in neurons and astrocytes were inverse to cholesterol level changes, though this association was not seen in microglia. Lastly, red fluorescent protein-labelled miR-335 mimic was visualized in both neurons and astrocytes after transfection and miR-335 expression changes were seen after transfection in astrocytes. Conclusions: Sterol levels are altered after OGD and may be associated with OGD changes. Transfection of miR-335 mimic and antagomiR is feasible and future studies using these tools will allow for better understanding of the effects of neonatal HIBI on sterol levels. This approach could allow for identification of targets to aid in developing therapeutics.https://digitalcommons.unmc.edu/chri_forum/1017/thumbnail.jp

Evaluation of brain cholesterol metabolism after neonatal hypoxic-ischemic brain injury

Introduction Neonatal hypoxic-ischemic brain injury (HIBI), resulting from impaired cerebral blood flow and oxygen delivery to the brain, affects at least 1.5 per 1,000 live births each year in the United States. Altered levels of cholesterol and cholesterol metabolites have been identified in brain tissue and in serum after adult brain injury such as traumatic brain injury and stroke. We hypothesized that there would be temporal and brain region-specific alterations in cholesterol and sterol precursors after neonatal HIBI. Methods Postnatal day 9 CD1 mouse pups were anesthetized with isoflurane and randomized to HIBI induced by carotid artery ligation or controls receiving sham surgery consisting of dissection without ligation (n=24/group). Pups were allowed to recover after surgery and then placed in a hypoxia chamber at 8% oxygen for HIBI or 21% for controls for 30 minutes. Each group was further divided into three sub-groups (n=8/group) for blood and brain tissue collection at 30 minutes, 24 hours, or 72 hours after injury. Brain tissue was dissected into four regions: cortex, cerebellum, striatum/thalamus, and hippocampus. For each region, protein was quantified by BCA assay, interleukin-6 (IL-6) levels were measured by ELISA as a marker of injury severity, and liquid chromatography mass spectrometry was performed to evaluate for the following sterols: cholesterol, desmosterol, 7-dehydrocholesterol, 8-dehydrocholesterol, and lanosterol. Levels were compared between HIBI and control groups at each time point and neuroanatomical region. Additionally, the four samples in each group demonstrating the most severe injury, as defined by IL-6 levels, were stratified as “severe injury”. Differences were analyzed with a two-sided Mann-Whitney test. Results When assessing the entire cohort, no statistically significant differences were seen between HIBI and controls with respect to temporal or regional differences for any of the sterols measured. In animals with severe HIBI, however, cholesterol, 7-dehydrocholesterol, 8-dehydrocholesterol, and desmosterol were higher in the cortex at 24 hours after injury compared to controls. Additionally, desmosterol was also elevated in the cerebellum but decreased in the striatum 24 hours after injury in the severely injured animals. Conclusion Severe neonatal encephalopathy appears to be associated with alterations in cortical brain sterol levels, peaking around 24 hours after injury. Further defining the aberrations in brain metabolism in infants with HIBI could provide opportunities for not only diagnostic biomarkers but also the development of targeted therapies.https://digitalcommons.unmc.edu/chri_forum/1003/thumbnail.jp

Neuroprotective therapies in the NICU in preterm infants: present and future (Neonatal Neurocritical Care Series)

Abstract: The survival of preterm infants has steadily improved thanks to advances in perinatal and neonatal intensive clinical care. The focus is now on finding ways to improve morbidities, especially neurological outcomes. Although antenatal steroids and magnesium for preterm infants have become routine therapies, studies have mainly demonstrated short-term benefits for antenatal steroid therapy but limited evidence for impact on long-term neurodevelopmental outcomes. Further advances in neuroprotective and neurorestorative therapies, improved neuromonitoring modalities to optimize recruitment in trials, and improved biomarkers to assess the response to treatment are essential. Among the most promising agents, multipotential stem cells, immunomodulation, and anti-inflammatory therapies can improve neural outcomes in preclinical studies and are the subject of considerable ongoing research. In the meantime, bundles of care protecting and nurturing the brain in the neonatal intensive care unit and beyond should be widely implemented in an effort to limit injury and promote neuroplasticity. Impact: With improved survival of preterm infants due to improved antenatal and neonatal care, our focus must now be to improve long-term neurological and neurodevelopmental outcomes. This review details the multifactorial pathogenesis of preterm brain injury and neuroprotective strategies in use at present, including antenatal care, seizure management and non-pharmacological NICU care. We discuss treatment strategies that are being evaluated as potential interventions to improve the neurodevelopmental outcomes of infants born prematurely

The Role of Micrornas in the Pathophysiology of Neonatal Hypoxic-ischemic Brain Injury

Neonatal hypoxic-ischemic brain injury (HIBI) is a devastating injury resulting from impaired blood flow and oxygen delivery to the brain at or around the time of birth. The subsequent metabolic failure and cellular injury in the brain can be partially attenuated by rapid initiation of therapeutic hypothermia, but even with prompt induction of hypothermia, more than one in four survivors suffer from major developmental disabilities – an indication of the critical need for more effective therapies. MicroRNAs (miRNA) may be able to act as therapeutic targets in neonatal HIBI; however, very little is known about the endogenous expression of miRNAs after neonatal HIBI nor the role that extracellular vesicle (EV)-delivered miRNAs may play in the neuroprotective effects of EV administration. Using temporal and regional sampling of brain tissue in a mouse model of neonatal HIBI followed by next-generation miRNA sequencing (miRNA-Seq), miRNA profiles of the different brain regions at 30 minutes and the whole brain at 24 and 72 hours after injury were obtained. EVs were then modified to optimize neuroprotection by hypoxia preconditioning, administered intranasally to the mouse model, and the EV miRNA content was analyzed by miRNA-Seq. The studies identified several promising miRNAs for future investigations into miRNA-based therapeutic interventions. Given the multifactorial nature of neonatal HIBI, it is likely that a combination of miRNAs would need to be targeted to achieve maximal benefit. Because of this, the list of promising miRNAs was grouped by targeted pathways, and future investigations should consider assessing the effects of altering one or more miRNA from each of the miRNA clusters. Additional mechanistic studies will be necessary to demonstrate whether the differentially expressed miRNAs may be beneficial or pathologic and whether the miRNAs detected in the EVs play a significant role in the neuroprotection seen after hypoxia preconditioned EV administration. Ultimately, given their broad effect profile, ease of administration, and small size allowing for effective blood-brain barrier crossing, miRNAs represent promising targets for improving brain injury and reducing developmental impairments in neonates suffering from HIBI

The impact of hypoxic-ischemic brain injury on stem cell mobilization, migration, adhesion, and proliferation

Neonatal hypoxic-ischemic encephalopathy continues to be a significant cause of death or neurodevelopmental delays despite standard use of therapeutic hypothermia. The use of stem cell transplantation has recently emerged as a promising supplemental therapy to further improve the outcomes of infants with hypoxic-ischemic encephalopathy. After the injury, the brain releases several chemical mediators, many of which communicate directly with stem cells to encourage mobilization, migration, cell adhesion and differentiation. This manuscript reviews the biomarkers that are released from the injured brain and their interactions with stem cells, providing insight regarding how their upregulation could improve stem cell therapy by maximizing cell delivery to the injured tissue

Ferroptosis: A Promising Therapeutic Target for Neonatal Hypoxic-Ischemic Brain Injury

Ferroptosis is a type of programmed cell death caused by phospholipid peroxidation that has been implicated as a mechanism in several diseases resulting from ischemic-reperfusion injury. Most recently, ferroptosis has been identified as a possible key injury mechanism in neonatal hypoxic-ischemic brain injury (HIBI). This review summarizes the current literature regarding the different ferroptotic pathways, how they may be activated after neonatal HIBI, and which current or investigative interventions may attenuate ferroptotic cell death associated with neonatal HIBI