Free Amino Acids in Hearts of Pediatric Patients With Congenital Heart Disease: The Effects of Cyanosis, Age, and Pathology

Integrated untargeted/targeted metabolomics identifies a putative oxylipin signature in patients with atrial fibrillation and coronary heart disease

Background and Objective

Atrial fibrillation (AF) and coronary heart disease (CHD) are closely related to metabolic dysregulation. However, the metabolic characteristics of AF patients with concomitant CHD remain unclear. The aims of this study were to elucidate the metabolic profiles of patients with AF and CHD to seek new therapeutic targets and related factors of AF combined with CHD.

Methods

Untargeted metabolomics and targeted oxylipins profiling were performed to characterize the serum metabolome landscape of patients with AF, CHD, and AF comorbid CHD.

Results

The serum metabolic fingerprints of patients with AF comorbid CHD were significantly differentiated from normal controls (NC) and individuals with AF or CHD alone, and the differentiated metabolites dominated by a variety of lipid alterations in the phospholipid and fatty acid metabolism. Furthermore, the targeted profiles of oxylipins demonstrated that the levels of arachidonic acid derivatives including prostaglandins, leukotrienes, hydroxy-docosahexaenoic acids, hydroxy-eicostetraenoic acids and hydroxy-eicosatrienoic acids in patients with AF and CHD were significantly different from those in the NC, AF, and CHD groups. Several prostaglandins were positively associated with echocardiographic indicators of myocardial remodeling.

Conclusions

This study updates metabolic insights of AF and CHD and provides potential therapeutic targets for preventing or treating AF comorbid CHD.

Early postnatal metabolic profile in neonates with critical CHDs

BACKGROUND

Cyanotic CHD is a life-threatening condition that presents with low oxygen saturation in the newborn period. Hypoxemia might cause alterations in the metabolic pathways. In the present study, we aimed to evaluate the early postnatal amino acid and carnitine/acylcarnitine profiles of newborn infants with cyanotic CHD.

METHODS

A single centre case-control study was conducted. Twenty-seven patients with cyanotic CHD and 54 healthy newborn controls were enrolled. As part of the neonatal screening programme, results of amino acid and carnitine/acylcarnitine were recorded and compared between groups.

RESULTS

Twenty-seven neonates with cyanotic CHD and 54 healthy newborns as controls were enrolled in the study. Cyanotic CHD neonates had higher levels of alanine, phenylalanine, leucine/isoleucine, citrulline, ornithine, C5, C5-OH; but lower levels of C3, C10, C12, C14, C14:1, C16, C16.1, C18, C5-DC, C6-DC, C16-OH, C16:1-OH when compared with the healthy controls.

CONCLUSION

This study showed that there are differences between patients with cyanotic CHD and healthy controls in terms of postnatal amino acid and carnitine/acylcarnitine profiles.

Differences in the serum metabolic profile to identify potential biomarkers for cyanotic versus acyanotic heart disease

BACKGROUND

Growth retardation, malnutrition, and failure to thrive are some of the consequences associated with congenital heart diseases. Several metabolic factors such as hypoxia, anoxia, and several genetic factors are believed to alter the energetics of the heart. Timely diagnosis and patient management is one of the major challenges faced by the clinicians in understanding the disease and provide better treatment options. Metabolic profiling has shown to be potential diagnostic tool to understand the disease.

OBJECTIVE

The present experiment was designed as a single center observational pilot study to classify and create diagnostic metabolic signatures associated with the energetics of congenital heart disease in cyanotic and acyanotic groups.

METHODS

Metabolic sera profiles were obtained from 35 patients with cyanotic congenital heart disease (TOF) and 23 patients with acyanotic congenital heart disease (ASD and VSD) using high resolution 1D 1H NMR spectra. Univariate and multivariate statistical analysis were performed to classify particular metabolic disorders associated with cyanotic and acyanotic heart disease.

RESULTS

The results show dysregulations in several metabolites in cyanotic CHD patients versus acyanotic CHD patients. The discriminatory metabolites were further analyzed with area under receiver operating characteristic (AUROC) curve and identified four metabolic entities (i.e. mannose, hydroxyacetone, myoinositol, and creatinine) which could differentiate cyanotic CHDs from acyanotic CHDs with higher specificity.

CONCLUSION

An untargeted metabolic approach proved to be helpful for the detection and distinction of disease-causing metabolites in cyanotic patients from acyanotic ones and can be useful for designing better and personalized treatment protocol.

TonEBP modulates the protective effect of taurine in ischemia-induced cytotoxicity in cardiomyocytes

Taurine, which is found at high concentration in the heart, exerts several protective actions on myocardium. Physically, the high level of taurine in heart is maintained by a taurine transporter (TauT), the expression of which is suppressed under ischemic insult. Although taurine supplementation upregulates TauT expression, elevates the intracellular taurine content and ameliorates the ischemic injury of cardiomyocytes (CMs), little is known about the regulatory mechanisms of taurine governing TauT expression under ischemia. In this study, we describe the TonE (tonicity-responsive element)/TonEBP (TonE-binding protein) pathway involved in the taurine-regulated TauT expression in ischemic CMs. Taurine inhibited the ubiquitin-dependent proteasomal degradation of TonEBP, promoted the translocation of TonEBP into the nucleus, enhanced TauT promoter activity and finally upregulated TauT expression in CMs. In addition, we observed that TonEBP had an anti-apoptotic and anti-oxidative role in CMs under ischemia. Moreover, the protective effects of taurine on myocardial ischemia were TonEBP dependent. Collectively, our findings suggest that TonEBP is a core molecule in the protective mechanism of taurine in CMs under ischemic insult.

Which is the better option during neonatal cardiopulmonary bypass: HTK solution or cold blood cardioplegia?

The optimal myocardial protection strategy for newborns/infants undergoing congenital heart surgery remains controversial. The purpose of this study was to compare myocardial protection using histidine-tryptophan-ketoglutarate (HTK) and cold blood cardioplegia in a neonatal piglet model. Twenty-one piglets were randomized to three groups: the control group (C group, n = 7), a single dose of HTK group (H group, n = 7), and multidose cold blood cardioplegia group (B group, n = 7). Animals in the two experimental groups were placed on hypothermic cardiopulmonary bypass, after which the ascending aorta was clamped for 2 hours. Immediately after declamping, both the difference between arterial and coronary sinus blood lactate concentrations and the oxygen extraction did not differ between the H group and the B group. At 3 hours after declamping, rise in serum troponin-T and creatine kinase isoenzyme MB levels showed no significant differences between the H group and the B group (p = 0.735 and p = 0.103, respectively). No significant differences were noted in the myocardial lactate content, ATP content, and histopathological score between the H group and the B group (p = 0.810, p = 0.158, and p = 0.399, respectively). Transfusion requirement in the B group was significantly more than that in the H group (p = 0.003). HTK solution provides equivalent myocardial protection to multidose cold blood cardioplegia for the neonatal heart with less transfusion requirement.

Porcine model of congenital heart defect with decreased pulmonary blood flow

A porcine model was produced to study the pathophysiology of congenital heart defect (CHD) with decreased pulmonary blood flow. Twenty piglets (1-2 months) were randomly divided as mild to moderate stenosis/T(1) group (n = 7) in which artificial atrial septal defect (ASD) with pulmonary artery banding generated a systolic pressure gradient of 20-30 mmHg; severe stenosis/T group (n = 7) group with a systolic pressure gradient of ≥30-50 mmHg; and controls/C group (n = 6) underwent sham surgery. At 1 month postoperatively, 64-slice computed tomography (CT) was performed. At 2 months, left-chest surgery was performed to measure ASD diameter, arterial blood gas, hemoglobin, and Trans-PABP. Our data show successful establishment of porcine CHD model. ASDs in T(1)/T(2) groups were 8.0 ± 0.5/8.9 ± 1.4 mm, respectively. Trans-PABP showed that the pressure increase in T(2) was higher (P < 0.01) than in T(1) group. Arterial blood PaO(2) and SaO(2) of T(1/)T(2) groups were significantly lower than controls. AoD was significantly lower in T(1) than in C group. Balloon dilation was significantly lower than AoD in T(1)/T(2) groups. Besides, one animal in T(1), two animals in T(2) ,and one animal in C group died. We conclude that ASD with pulmonary artery banding is a successful intervention to establish such a model, and our findings may influence the treatment of patients with similar heart disease.