Math1 Is Essential for the Development of Hindbrain Neurons Critical for Perinatal Breathing

SummaryMice lacking the proneural transcription factor Math1 (Atoh1) lack multiple neurons of the proprioceptive and arousal systems and die shortly after birth from an apparent inability to initiate respiration. We sought to determine whether Math1 was necessary for the development of hindbrain nuclei involved in respiratory rhythm generation, such as the parafacial respiratory group/retrotrapezoid nucleus (pFRG/RTN), defects in which are associated with congenital central hypoventilation syndrome (CCHS). We generated a Math1-GFP fusion allele to trace the development of Math1-expressing pFRG/RTN and paratrigeminal neurons and found that loss of Math1 did indeed disrupt their migration and differentiation. We also identified Math1-dependent neurons and their projections near the pre-Bötzinger complex, a structure critical for respiratory rhythmogenesis, and found that glutamatergic modulation reestablished a rhythm in the absence of Math1. This study identifies Math1-dependent neurons that are critical for perinatal breathing that may link proprioception and arousal with respiration

Mild hypoxic-ischemic encephalopathy (HIE): Timing and pattern of MRI brain injury

BACKGROUND: Mild hypoxic-ischemic encephalopathy (HIE) is increasingly recognized as a risk factor for neonatal brain injury. We examined the timing and pattern of brain injury in mild HIE. METHODS: This retrospective cohort study includes infants with mild HIE treated at 9 hospitals. Neonatal brain MRIs were scored by 2 reviewers using a validated classification system, with discrepancies resolved by consensus. Severity and timing of MRI brain injury (i.e., acute, subacute, chronic) was scored on the subset of MRIs that were performed at or before 8 days of age. RESULTS: Of 142 infants with mild HIE, 87 (61%) had injury on MRI at median age 5 (IQR 4-6) days. Watershed (23%), deep gray (20%) and punctate white matter (18%) injury were most common. Among the 125 (88%) infants who received a brain MRI at ≤8 days, mild (44%) injury was more common than moderate (11%) or severe (4%) injury. Subacute (37%) lesions were more commonly observed than acute (32%) or chronic lesions (1%). CONCLUSION: Subacute brain injury is common in newborn infants with mild HIE. Novel neuroprotective treatments for mild HIE will ideally target both subacute and acute injury mechanisms. IMPACT: Almost two-thirds of infants with mild HIE have evidence of brain injury on MRI obtained in the early neonatal period. Subacute brain injury was seen in 37% of infants with mild HIE. Neuroprotective treatments for mild HIE will ideally target both acute and subacute injury mechanisms

Parental Factors Associated With the Decision to Participate in a Neonatal Clinical Trial

Importance: It remains poorly understood how parents decide whether to enroll a child in a neonatal clinical trial. This is particularly true for parents from racial or ethnic minority populations. Understanding factors associated with enrollment decisions may improve recruitment processes for families, increase enrollment rates, and decrease disparities in research participation. Objective: To assess differences in parental factors between parents who enrolled their infant and those who declined enrollment for a neonatal randomized clinical trial. Design, setting, and participants: This survey study conducted from July 2017 to October 2019 in 12 US level 3 and 4 neonatal intensive care units included parents of infants who enrolled in the High-dose Erythropoietin for Asphyxia and Encephalopathy (HEAL) trial or who were eligible but declined enrollment. Data were analyzed October 2019 through July 2020. Exposure: Parental choice of enrollment in neonatal clinical trial. Main outcomes and measures: Percentages and odds ratios (ORs) of parent participation as categorized by demographic characteristics, self-assessment of child's medical condition, study comprehension, and trust in medical researchers. Survey questions were based on the hypothesis that parents who enrolled their infant in HEAL differ from those who declined enrollment across 4 categories: (1) infant characteristics and parental demographic characteristics, (2) perception of infant's illness, (3) study comprehension, and (4) trust in clinicians and researchers. Results: Of a total 387 eligible parents, 269 (69.5%) completed the survey and were included in analysis. This included 183 of 242 (75.6%) of HEAL-enrolled and 86 of 145 (59.3%) of HEAL-declined parents. Parents who enrolled their infant had lower rates of Medicaid participation (74 [41.1%] vs 47 [55.3%]; P = .04) and higher rates of annual income greater than $55 000 (94 [52.8%] vs 30 [37.5%]; P = .03) compared with those who declined. Black parents had lower enrollment rates compared with White parents (OR, 0.35; 95% CI, 0.17-0.73). Parents who reported their infant's medical condition as more serious had higher enrollment rates (OR, 5.7; 95% CI, 2.0-16.3). Parents who enrolled their infant reported higher trust in medical researchers compared with parents who declined (mean [SD] difference, 5.3 [0.3-10.3]). There was no association between study comprehension and enrollment. Conclusions and relevance: In this study, the following factors were associated with neonatal clinical trial enrollment: demographic characteristics (ie, race/ethnicity, Medicaid status, and reported income), perception of illness, and trust in medical researchers. Future work to confirm these findings and explore the reasons behind them may lead to strategies for better engaging underrepresented groups in neonatal clinical research to reduce enrollment disparities

Blalock-Taussig shunt: experience from the developing world

Background: Palliative procedures have a role in congenital cardiac malformations that do not permit a complete early repair, and in centres where facilities for complete early repair do not exist. The lack of data on modified Blalock-Taussig shunt from developing countries prompted this analysis. Methods: We report a retrospective study of 70 Blalock-Taussig shunt procedures in 63 patients over an 8-year period. Most of the procedures (54.0%) were done on children less than 4 months of age. Thirty-nine (58%) patients had Tetralogy of Fallot; the remaining patients had a wide spectrum of lesions. Results: In the first year of the review period, the classical Blalock-Taussig shunt was done in six patients (9.5%) and the modified Blalock-Taussig shunt was used thereafter. In 49 patients who were followed up long term, clinical congestive cardiac failure developed in three (6%) and shunt failure was reported in 10 (14%). Of the 16 (33%) total deaths, six had serious comorbid conditions preoperatively. CONCLUSIONS: The Blalock-Taussig shunt is a relatively safe palliative procedure, requiring fewer resources and less expertise than corrective surgery, making it a suitable option in developing countries

Two-Year Outcomes of Infants with Stage 2 or Higher Retinopathy of Prematurity: Results from a Large Multicenter Registry.

OBJECTIVE:  To define the incidence of ophthalmologic morbidities in the first 2 years of life among infants diagnosed with stage 2 or higher retinopathy of prematurity (ROP). STUDY DESIGN:  We prospectively enrolled premature infants with stage 2 or higher ROP. The infants were followed up for 2 years, and we report on data collected from outpatient ophthalmology and primary care visits. RESULTS:  We enrolled 323 infants who met inclusion criteria, of which 112 (35%) received treatment with laser surgery (90) or bevacizumab (22). Two-year follow-up was available for 292 (90%) of the cohort. The most common ophthalmologic conditions at follow-up were hyperopia (35%), astigmatism (30%), strabismus (21.9%), myopia (19.2%), anisometropia (12%), and amblyopia (12%). Severe ophthalmologic morbidities such as retinal detachment and cataracts were rare, but occurred in both treated and untreated infants. Overall, 22.6% of the infants were wearing glasses at 2 years, including 8.5% of the untreated infants. CONCLUSION:  Patients with stage 2 or higher ROP remain at significant risk for ophthalmological morbidity through 2 years of age. Infants with regression of subthreshold ROP who do not require treatment represent an underrecognized population at long-term ophthalmological risk. CLINICALTRIALS. GOV IDENTIFIER:  NCT01559571

Excitatory neurons of the proprioceptive, interoceptive, and arousal hindbrain networks share a developmental requirement for Math1

Hindbrain networks important for sensation and arousal contain diverse neuronal populations with distinct projections, yet share specific characteristics such as neurotransmitter expression. The relationship between the function of these neurons, their developmental origin, and the timing of their migration remains unclear. Mice lacking the proneural transcription factor Math1 (Atoh1) lose neurons essential for hearing, balance, and unconscious proprioception. By using a new, inducible Math1Cre*PR allele, we found that Math1 is also required for the conscious proprioceptive system, including excitatory projection neurons of the dorsal column nuclei and for vital components of the interoceptive system, such as Barrington's nucleus, that is closely associated with arousal. In addition to specific networks, Math1 lineages shared specific neurotransmitter expression, including glutamate, acetylcholine, somatostatin, corticotropin releasing hormone, and nitric oxide. These findings identify twenty novel Math1 lineages and indicate that the Math1 network functions partly as an interface for conscious (early-born) and unconscious (late-born) proprioceptive inputs to the cortex and cerebellum, respectively. In addition, these data provide previously unsuspected genetic and developmental links between proprioception, interoception, hearing, and arousal