Paradoxical relationship between N-terminal proatrial natriuretic peptide and filling pressure in adults with cyanotic congenital heart disease

A multi-omics approach reveals molecular mechanisms by which phthalates induce cardiac defects in zebrafish (Danio rerio)

The potential risks of phthalates affecting human and animal health as well as the environment are emerging as serious concerns worldwide. However, the mechanism by which phthalates induce developmental effects is under debate. Herein, we found that embryonic exposure of zebrafish to di-(2-ethylhexyl) phthalate (DEHP) and di-butyl phthalate (DBP) increased the rate of heart defects including abnormal heart rate and pericardial edema. Changes in the transcriptional profile demonstrated that genes involved in the development of the heart, such as tbx5b, nppa, ctnt, my17, cmlc1, were significantly altered by DEHP and DBP at 50 μg/L, which agreed with the abnormal cardiac outcomes. Methylated DNA immunoprecipitation sequencing (MeDIP-Seq) further showed that significant hypomethylation of nppa and ctnt was identified after DEHP and DBP exposure, which was consistent with the up-regulation of these genes. Notably, hypermethylation on the promoter region (<1 kb) of tbx5b was found after DEHP and DBP exposure, which might be responsible for its decrease in transcription. In conclusion, phthalates have the potential to induce cardiac birth defects, which might be associated with the transcriptional regulation of the involved developmental factors such as tbx5b. These findings would contribute to understand the molecular pathways that mediated the cardiac defects caused by phthalates.

Long-term results after palliative intra-cardiac repair for tetralogy of Fallot and diminutive pulmonary arteries

BACKGROUND

In patients with tetralogy of Fallot with the diminutive pulmonary arteries, we sometimes have to give up the complete intra-cardiac repair due to insufficient growth of the pulmonary arteries. We have carried out palliative intra-cardiac repair using a fenestrated patch.

METHODS

Of all 202 patients with tetralogy of Fallot in our centre since 1996, five patients (2.5%) with the diminutive pulmonary arteries underwent palliative intra-cardiac repair using a fenestrated patch. Mean operative age was 1.8 years. Previous operation was Blalock-Taussig shunt in 4. At operation, the ventricular septal defect was closed using a fenestrated patch and the right ventricular outflow tract was enlarged. Follow-up period was 9.8 ± 2.6 years.

RESULTS

There were no operative and late deaths. Fenestration closed spontaneously on its own in four patients 2.7 ± 2.1 years after the intra-cardiac repair with a stable haemodynamics; however, the last patient with the smallest pulmonary artery index had supra-systemic pressure of the right ventricle post-operatively. The fenestration was emergently enlarged. Systemic arterial oxygen saturation was significantly and dramatically increased from 83.5 to 94% after the palliative intra-cardiac repair, and to 98% at the long term. A ratio of systolic pressure of the right ventricle to the left was significantly decreased to 0.76 ± 0.12 at the long term. Now all five patients were Ross classification class I.

CONCLUSION

Although frequent catheter and surgical interventions were needed after the palliative intra-cardiac repair, this repair might be a choice improving quality of life with good results in patients with tetralogy of Fallot associated with the diminutive pulmonary arteries.

Biomarkers in congenital heart disease: do natriuretic peptides hold the key?

Congenital heart disease is the most common congenital abnormality. The long-term prognosis of these patients has changed significantly over the last half century, thanks to improvements in cardiovascular diagnosis, surgery and postoperative care. However, residual lesions are not uncommon and many of the interventions performed remain palliative rather than reparative, leading to the development of ventricular dysfunction and heart failure. Natriuretic peptides are well-established markers of disease severity and prognosis in patients with heart failure due to noncongenital (acquired) heart disease. However, the role of biomarkers in congenital heart disease is unclear. This review highlights the impact of neurohormonal activation in patients with congenital heart disease, as well as the usefulness of assessing natriuretic peptide levels in specific clinical situations.

Heart transplantation in adults with end-stage congenital heart disease

Residual abnormalities in cardiac structure and function predispose adults with congenital heart disease to late-onset heart failure and its complications. Evaluation of this population requires collaboration between adult congenital and heart failure specialists. In addition to assessing heart transplant eligibility, clinicians must balance the risks of premature listing against progressive heart failure and increased waiting list mortality. Following heart transplantation, adults with congenital heart disease have higher mortality due to an increased risk of bleeding, infection and donor right heart failure secondary to pulmonary hypertension. Concerns relating to increased early mortality should be balanced against superior long-term survival in adult congenital heart disease patients surviving beyond the first year after heart transplantation.

Natriuretic peptides in hormonal regulation of hypoxia responses

The possibility that natriuretic peptides' effects are important in hypoxia responses of vertebrates is reviewed. Both the transcription and release of natriuretic peptides are affected by oxygen tension. Furthermore, many of the effects observed in hypoxia, such as diuresis and a reduction of plasma volume, are also caused by treatment of the animal with natriuretic peptides. Also, several clinical observations about changes in natriuretic peptide levels in, e.g., sleep apnea and cyanotic congenital heart disease, are consistent with the idea that hypoxia is involved in the etiology of conditions, in which natriuretic peptide levels increase. Virtually all published information on the relationship between oxygen and natriuretic peptides is based on human studies. Because hypoxic conditions are more common in aquatic than terrestrial environments, future studies about the possible role of natriuretic peptides in hypoxia, as well as the role of hypoxia in the evolution of natriuretic peptides, including the different subtypes, should increasingly involve also aquatic organisms.

Change in plasma volume during peak exercise in patients with cyanotic congenital heart disease after definitive operation

OBJECTIVES

To evaluate changes in plasma volume (deltaPV) during exercise in patients with single ventricular physiology with cyanosis; post-Fontan patients; and in patients after right ventricular outflow tract reconstruction (RVOTR).

BACKGROUND

Compensatory mechanisms which regulate body fluid volumes operate in heart failure patients to maintain blood pressure. A better understanding of this pathophysiological process, especially during exercise, should help manage and follow such patients.

METHODS

Twenty-six CHD patients (14+/-4 years), including 5 cyanotic patients, 12 after the Fontan operation, 9 after RVOTR, and 13 controls (14+/-5 years), performed a treadmill exercise test. DeltaPV from rest to peak was calculated and compared with changes in cardiovascular responses, plasma total protein (TP), norepinephrine (NE), osmolality (Osm), and blood lactate concentration (La).

RESULTS

DeltaPV was smaller in CHD patients than in controls (Cyanotic: -5.9%, Fontan: -10.0%, RVOTR: -11.4%,

CONTROLS

-14.5%, p<0.001). In all subjects, peak heart rate, systolic blood pressure and oxygen uptake correlated inversely with deltaPV (p<0.05 to 0.005). DeltaPV correlated inversely with changes in TP, NE, and La (p<0.005 for all), but not with the change in Osm. In CHD patients, the deltaPV correlated only with the NE increase (p<0.01).

CONCLUSIONS

DeltaPV is smaller in CHD patients than in controls, especially in cyanotic patients. The smaller increases in cardiovascular responses during exercise and La are associated with the small deltaPV. These mechanisms may help to maintain cardiac output and increased sympathetic nervous activity may be beneficial to ensure sufficient perfusion pressure against deltaPV during exercise.