Mutations in genes related to myocyte contraction and ventricular septum development in non-syndromic tetralogy of Fallot.

Objective: Eighty percent of patients with a diagnosis of tetralogy of Fallot (TOF) do not have a known genetic etiology or syndrome. We sought to identify key molecular pathways and biological processes that are enriched in non-syndromic TOF, the most common form of cyanotic congenital heart disease, rather than single driver genes to elucidate the pathogenesis of this disease. Methods: We undertook exome sequencing of 362 probands with non-syndromic TOF and their parents within the Pediatric Cardiac Genomics Consortium (PCGC). We identified rare (minor allele frequency <1 × 10-4), de novo variants to ascertain pathways and processes affected in this population to better understand TOF pathogenesis. Pathways and biological processes enriched in the PCGC TOF cohort were compared to 317 controls without heart defects (and their parents) from the Simons Foundation Autism Research Initiative (SFARI). Results: A total of 120 variants in 117 genes were identified as most likely to be deleterious, with CHD7, CLUH, UNC13C, and WASHC5 identified in two probands each. Gene ontology analyses of these variants using multiple bioinformatic tools demonstrated significant enrichment in processes including cell cycle progression, chromatin remodeling, myocyte contraction and calcium transport, and development of the ventricular septum and ventricle. There was also a significant enrichment of target genes of SOX9, which is critical in second heart field development and whose loss results in membranous ventricular septal defects related to disruption of the proximal outlet septum. None of these processes was significantly enriched in the SFARI control cohort. Conclusion: Innate molecular defects in cardiac progenitor cells and genes related to their viability and contractile function appear central to non-syndromic TOF pathogenesis. Future research utilizing our results is likely to have significant implications in stratification of TOF patients and delivery of personalized clinical care.

Delta-like ligand-4 regulates Notch-mediated maturation of second heart field progenitor-derived pharyngeal arterial endothelial cells.

Mesodermal progenitors in the second heart field (SHF) express Delta-like-ligand 4 (Dll4) that regulates Notch-mediated proliferation. As cells of SHF lineage mature to assume endocardial and myocardial cell fates, we have shown that Dll4 expression is lost, and the subsequent expression of another Notch ligand Jagged1 regulates Notch-mediated maturation events in the developing heart. A subset of SHF progenitors also matures to form the pharyngeal arch artery (PAA) endothelium. Dll4 was originally identified as an arterial endothelial-specific Notch ligand that plays an important role in blood vessel maturation, but its role in aortic arch maturation has not been studied to date secondary to the early lethality observed in Dll4 knockout mice. We show that, unlike in SHF-derived endocardium and myocardium, Dll4 expression persists in SHF-derived arterial endothelial cells. Using SHF-specific conditional deletion of Dll4, we demonstrate that as SHF cells transition from their progenitor state to an endothelial fate, Dll4-mediated Notch signalling switches from providing proliferative to maturation cues. Dll4 expression maintains arterial identity in the PAAs and plays a critical role in the maturation and re-organization of the 4th pharyngeal arch artery, in particular. Haploinsufficiency of Dll4 in SHF leads to highly penetrant aortic arch artery abnormalities, similar to those observed in the clinic, primarily resulting from aberrant reorganization of bilateral 4th pharyngeal arch arteries. Hence, we show that cells of SHF lineage that assume an arterial endothelial fate continue to express Dll4 and the resulting Dll4-mediated Notch signalling transitions from an early proliferative to a later maturation role during aortic arch development.

Educational, psychosocial, and clinical impact of SARS-CoV-2 (COVID-19) pandemic on medical students in the United States.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic altered education, exams, and residency applications for United States medical students. AIM: To determine the specific impact of the pandemic on US medical students and its correlation to their anxiety levels. METHODS: An 81-question survey was distributed via email, Facebook and social media groups using REDCapTM. To investigate risk factors associated with elevated anxiety level, we dichotomized the 1-10 anxiety score into low (≤ 5) and high (≥ 6). This cut point represents the 25th percentile. There were 90 (29%) shown as low anxiety and 219 (71%) as high anxiety. For descriptive analyses, we used contingency tables by anxiety categories for categorical measurements with chi square test, or mean ± STD for continuous measurements followed by t-test or Wilcoxson rank sum test depending on data normality. Least Absolute Shrinkage and Selection Operator was used to select important predictors for the final multivariate model. Hierarchical Poisson regression model was used to fit the final multivariate model by considering the nested data structure of students clustered within State. RESULTS: 397 medical students from 29 states were analyzed. Approximately half of respondents reported feeling depressed since the pandemic onset. 62% of participants rated 7 or higher out of 10 when asked about anxiety levels. Stressors correlated with higher anxiety scores included "concern about being unable to complete exams or rotations if contracting COVID-19" (RR 1.34; 95%CI: 1.05-1.72, P = 0.02) and the use of mental health services such as a "psychiatrist" (RR 1.18; 95%CI: 1.01-1.3, P = 0.04). However, those students living in cities that limited restaurant operations to exclusively takeout or delivery as the only measure of implementing social distancing (RR 0.64; 95%CI: 0.49-0.82, P < 0.01) and those who selected "does not apply" for financial assistance available if needed (RR 0.83; 95%CI: 0.66-0.98, P = 0.03) were less likely to have a high anxiety. CONCLUSION: COVID-19 significantly impacted medical students in numerous ways. Medical student education and clinical readiness were reduced, and anxiety levels increased. It is vital that medical students receive support as they become physicians. Further research should be conducted on training medical students in telemedicine to better prepare students in the future for pandemic planning and virtual healthcare.

Association of Alcohol Use Diagnostic Codes in Pregnancy and Offspring Conotruncal and Endocardial Cushion Heart Defects.

Background The pathogenesis of congenital heart disease (CHD) remains largely unknown, with only a small percentage explained solely by genetic causes. Modifiable environmental risk factors, such as alcohol, are suggested to play an important role in CHD pathogenesis. We sought to evaluate the association between prenatal alcohol exposure and CHD to gain insight into which components of cardiac development may be most vulnerable to the teratogenic effects of alcohol. Methods and Results This was a retrospective analysis of hospital discharge records from the California Office of Statewide Health Planning and Development and linked birth certificate records restricted to singleton, live-born infants from 2005 to 2017. Of the 5 820 961 births included, 16 953 had an alcohol-related International Classification of Diseases, Ninth and Tenth Revisions (ICD-9; ICD-10) code during pregnancy. Log linear regression was used to calculate risk ratios (RR) for CHD among individuals with an alcohol-related ICD-9 and ICD10 code during pregnancy versus those without. Three models were created: (1) unadjusted, (2) adjusted for maternal demographic factors, and (3) adjusted for maternal demographic factors and comorbidities. Maternal alcohol-related code was associated with an increased risk for CHD in all models (RR, 1.33 to 1.84); conotruncal (RR, 1.62 to 2.11) and endocardial cushion (RR, 2.71 to 3.59) defects were individually associated with elevated risk in all models. Conclusions Alcohol-related diagnostic codes in pregnancy were associated with an increased risk of an offspring with a CHD, with a particular risk for endocardial cushion and conotruncal defects. The mechanistic basis for this phenotypic enrichment requires further investigation.

Concomitant genetic defects potentiate the adverse impact of prenatal alcohol exposure on cardiac outflow tract maturation.

BACKGROUND: Prenatal alcohol exposure (PAE) is associated with an increased incidence of congenital heart defects (CHD), in particular outflow tract (OFT) defects. However, the variability in the incidence of CHD following PAE has not been fully explored. We hypothesize that a concomitant, relevant genetic defect would potentiate the adverse effect of PAE and partially explain the variability of PAE-induced CHD incidence. METHODS: The OFT is formed by the second heart field (SHF). Our PAE model consisted of two intraperitoneal injections (3 g/kg, separated by 6 hr) of 30% ethanol on E6.5 during SHF specification. The impact of genetic defects was studied by SHF-specific loss of Delta-like ligand 4 (Dll4), fibroblast growth factor 8 (Fgf8) and Islet1. RESULTS: Acute PAE alone significantly increased CHD incidence (4% vs. 26%, p = .015) with a particular increase in OFT alignment defects, viz., double outlet right ventricle (0 vs. 9%, p = .02). In embryos with a SHF genetic defect, acute PAE significantly increased CHD incidence (14 vs. 63%, p < .001), including double outlet right ventricle (6 vs. 50%, p < .001) compared to controls. PAE (p = .01) and heterozygous loss of Dll4 (p = .04) were found to independently contribute to CHD incidence, while neither Islet1 nor Fgf8 defects were found to be significant. CONCLUSIONS: Our model recapitulates the increased incidence of OFT alignment defects seen in the clinic due to PAE. The presence of a concomitant SHF genetic mutation increases the incidence of PAE-related OFT defects. An apparent synergistic interaction between PAE and the loss of DLL4-mediated Notch signaling in OFT alignment requires further analysis.

Using Technology to Improve Adherence to HIV Medications in Transitional Age Youth: Research Reviewed, Methods Tried, Lessons Learned.

In transitional age youth living with HIV or AIDS, non-adherence (<80%) to anti-retroviral medication is associated with viral resistance, disease progression, and an increased risk of death. This feasibility study investigated the Maya MedMinder electronic pillbox and cell phone texting with personalized motivational interviewing strategies to improve medication adherence in non-adherent youth. Twenty patients out of 30 identified as non-adherent by the Pediatric HIV team at the Medical University of South Carolina were approached, and 15 were recruited (Ages 12 to 20; 13.3% male, 86.7% female; 100% African-American). Following baseline MedMinder monitoring, subjects were randomized to intervention groups with reminder signals on or off. The time medications were taken was collected by the MedMinder, resulting in adherence scores. All were interviewed for readiness to change utilizing the Motivational Interviewing (MI) Stages of Change scores. Viral load and CD4 labs were scheduled every 6 weeks. Despite monetary incentives and personalized support, recruitment and adherence to the protocol was a challenge. Only 6/15 subjects completed the entire study scheduled for 6-months .Stages of change scores revealed that those that transitioned to making changes had higher CD4 percentages midway through the study. Challenges included missed appointments and labs despite efforts by text and phone to schedule convenient appointment times with participants. Device challenges included the large size of the MedMinder and faulty electronic signaling, especially from rural areas. The methodology was feasible with these patients. This small feasibility study highlights that technological tools to promote adherence and motivational enhancement strategies in teens and young adults who are non-adherent to HIV medication regimens can enhance biomarker outcomes associated with medication adherence.