Evolution, genetics, and the etiology of congenital cardiovascular malformations

Pcsk5 is required in the early cranio-cardiac mesoderm for heart development

Background

Loss of proprotein convertase subtilisin/kexin type 5 (Pcsk5) results in multiple developmental anomalies including cardiac malformations, caudal regression, pre-sacral mass, renal agenesis, anteroposterior patterning defects, and tracheo-oesophageal and anorectal malformations, and is a model for VACTERL/caudal regression/Currarino syndromes (VACTERL association - Vertebral anomalies, Anal atresia, Cardiac defects, Tracheoesophageal fistula and/or Esophageal atresia, Renal & Radial anomalies and Limb defects).

Results

Using magnetic resonance imaging (MRI), we examined heart development in mouse embryos with zygotic and cardiac specific deletion of Pcsk5. We show that conditional deletion of Pcsk5 in all epiblastic lineages recapitulates all developmental malformations except for tracheo-esophageal malformations. Using a conditional deletion strategy, we find that there is an essential and specific requirement for Pcsk5 in the cranio-cardiac mesoderm for cardiogenesis, but not for conotruncal septation or any other aspect of embryonic development. Surprisingly, deletion of Pcsk5 in cardiogenic or pharyngeal mesodermal progenitors that form later from the cranio-cardiac mesoderm does not affect heart development. Neither is Pcsk5 essential in the neural crest, which drives conotruncal septation.

Conclusions

Our results suggest that Pcsk5 may have an essential and early role in the cranio-cardiac mesoderm for heart development. Alternatively, it is possible that Pcsk5 may still play a critical role in Nkx2.5-expressing cardiac progenitors, with persistence of mRNA or protein accounting for the lack of effect of deletion on heart development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12861-017-0148-y) contains supplementary material, which is available to authorized users.

Gestational and family risk factors for carriers of congenital heart defects in southern Brazil

BACKGROUND

Congenital heart disease (CHD) is a serious threat to public health. Despite this, its etiology is poorly understood and few cardiac teratogens have been defined. The aim of the present study was to identify gestational and family risk factors for CHD in a sample of patients from a pediatric hospital in southern Brazil.

METHODS

A prospective and consecutive sample from subjects with or without CHD, hospitalized at a pediatric intensive care unit, was enrolled. All patients with CHD underwent a GTG-banding karyotype. Chromosomal abnormalities were observed in 47 subjects (15.8%), and these were excluded from the study. The final sample consisted of 250 CHD subjects and 303 controls.

RESULTS

After statistical analysis, using logistic regression, the variables age, rural location, gestational loss, use of anti-hypertensive medication, antibiotics and alcohol in the first trimester of pregnancy were all independently associated with CHD. These results were similar to those of some studies and different from others. It should be noted, however, that, for several variables, the data in the literature as well as the present study were insufficient to determine risk.

CONCLUSIONS

Some differences found may be explained by genetic factors and sociocultural diversity. In contrast, because CHD consists of a heterogeneous group of lesions, the etiology may vary. The standardization of research data and classification of methods for future studies are essential.

Is there an association between bicuspid aortic valve and neuroblastoma?

An association has been reported between neuroblastoma and congenital heart disease, frequently bicuspid aortic valve [Holzer and Franklin. Arch Dis Child 2002;87:61-64; George et al. J Pediatr 2004;144:444-448; Friedman et al. Pediatr Cardiol 1998;19:480-481; Monte et al. Am J Pediatr Hematol Oncol 1985;7:109-116]. To evaluate this in a large patient group with neuroblastoma, we examined echocardiograms of patients with neuroblastoma from 1987 to January 2007 to determine if there was a higher incidence of bicuspid aortic valves compared to the general population without neuroblastoma. We found that only 0.7% of neuroblastoma patients had the congenital heart defect of bicuspid aortic valves compared with 1-2% in the general population [Braverman et al. Curr Prob Cardiol 2005;30:470-522]. Our data show that neuroblastoma is not associated with bicuspid aortic valves.