Selective perfusion of coronary vasculature in preterm sheep: a methodological innovation undermined by unfavourable operation of the foramen ovale.

Antenatal cardiac intervention affords new prospects for hypoplastic left heart syndrome. Its success, however, may come not only from absence of impediments to blood flow but also from a sufficiently developed cardiac wall. Here, we examined the feasibility to perfuse selectively the fetal coronary circulation for treatment with growth promoting agents. Pregnant sheep (94-114 days gestation, term 145 days) were used. An aortic stop-flow procedure was developed for intracoronary access in the nonexposed fetus and human mesenchymal stem cells and their exosomes served as test agents. We found that aortic stop-flow ensures preferential distribution of fluorescent microspheres to the heart. However, intracoronary administration of stem cells or exosomes was detrimental, with fetal demise occurring around surgery or at variable intervals afterwards. Coincidentally, stop-flow caused by itself a marked rise of intraluminal pressure within the occluded aorta along with histological signs of coronary obstruction. We conclude that it is feasible to perfuse selectively the coronary circulation of the preterm fetus, but treatments are not compatible with survival of the animals. The cause for failure is found in the absence of hemodynamic compensation to stop-flow via a left-to-right shunt. This unexpected event is attributed to a largely membranous foramen ovale, characteristic of sheep, that collapses under pressure.

Metatropic dysplasia in third trimester of pregnancy and a novel causative variant in the TRPV4 gene.

Prenatal diagnosis of skeletal dysplasias is particularly difficult for many reasons and differentiating these disorders in the prenatal period can be challenging because they are rare and many of the ultrasound findings are not necessarily pathognomonic for a specific disorder. The diagnosis is often made just after birth or exitus. The prenatal diagnosis of osteochondrodysplasias is based predominantly upon fetal ultrasound findings and it focuses substantially on the possible lethality of the disorder, without always being able to find a specific name for the disorder. Metatropic dysplasia is a rare osteochondrodysplasia due to mutations in the TRPV4 gene: TRPV4 is a cation channel, non-selectively permeable to calcium, encoded by a gene on chromosome 12q24.11; it is widely expressed and involved in many different physiological processes through responses to several different stimuli (physical, chemical, and hormonal) in ciliated epithelial cells. The exact incidence of this disorder is not known, however less than a hundred cases have been reported at present, with only two prenatal reports but without any reference to the molecular test. We describe the first report of molecular diagnosis of metatropic dysplasia carried out in prenatal diagnosis: the molecular testing of the TRPV4 (transient receptor potential cation channel, subfamily V, member 4, MIM *605427) gene in our case, in fact, detected a causative variant, confirming the diagnostic suspicion, which was made possible thanks also to the utilization of MRI and CT scan. In our case different imaging methods together with the close cooperation of a multidisciplinary team and test availability, allowed an accurate diagnosis.