Familial aggregation of "apple peel" intestinal atresia and cardiac left-sided obstructive lesions: A possible causal relationship with NOTCH1 gene mutations.

"Apple peel" intestinal atresia is a rare form of small bowel atresia, in which the duodenum or proximal jejunum ends in a blind pouch and the distal small bowel wraps around its vascular supply, in a spiral resembling an apple peel. The etiology of "apple peel" intestinal atresia is presently unknown, although a congenital or acquired intestinal vascular accident can have a role in the pathogenesis. We report a family in which the proband affected by "apple peel" intestinal atresia, had a sibling (an interrupted pregnancy), and a paternal cousin with cardiac left-sided obstructive lesions. Molecular testing for NOTCH1 gene was carried out in the proband, because pathogenic mutations in this gene have been associated with familial and sporadic cardiac left-sided obstructive lesions and vascular anomalies, both isolated or within the spectrum of the Adams-Oliver syndrome (AOS). The heterozygous c.2734C>T (p.Arg912Trp) NOTCH1 variant was found in the proband with "apple peel" intestinal atresia and in his father. This result argues for a possible causal relationship between NOTCH1 gene mutations and some forms of intestinal defects, through a vascular mechanism. The spectrum of NOTCH1-associated malformations is widened. Genetic counseling should take into account intrafamilial variable clinical expression and incomplete penetrance.

Mannose-binding lectin (MBL) insufficiency protects against the development of systemic inflammatory response after pediatric cardiac surgery.

We investigated MBL2 and MASP2 genotypes, serum MBL (mannose-binding lectin) levels and activities of its complexes with associated serine proteases (MASP-1, MASP -2), in relation to complications following cardiac surgery in 195 children. The incidence of SIRS was lower in patients carrying MBL2 A/O and O/O genotypes (p=0.024). Children with MBL levels <500ng/ml had a lower risk of SIRS (p=0.014) and fever (p=0.044). Median MBL concentration was higher in patients who developed SIRS (p=0.048) but lower in those with post-operative infections (p=0.046). MBL-MASP-2 activities <100mU/ml protected from SIRS (p=0.007), low cardiac output syndrome (p=0.03) and multiorgan failure (p=0.012). In contrast, MBL2 YA/YA genotypes were associated with SIRS (p=0.018), low cardiac output syndrome (p=0.018), fever (p=0.018) and high inotropic score (VIS>30) (p=0.021). Thus, low MBL concentrations and associated genotypes may protect patients from systemic inflammation while high MBL serum levels and corresponding genotypes are risk factors of postoperative complications.

Meox2/Tcf15 heterodimers program the heart capillary endothelium for cardiac fatty acid uptake.

BACKGROUND: Microvascular endothelium in different organs is specialized to fulfill the particular needs of parenchymal cells. However, specific information about heart capillary endothelial cells (ECs) is lacking. METHODS AND RESULTS: Using microarray profiling on freshly isolated ECs from heart, brain, and liver, we revealed a genetic signature for microvascular heart ECs and identified Meox2/Tcf15 heterodimers as novel transcriptional determinants. This signature was largely shared with skeletal muscle and adipose tissue endothelium and was enriched in genes encoding fatty acid (FA) transport-related proteins. Using gain- and loss-of-function approaches, we showed that Meox2/Tcf15 mediate FA uptake in heart ECs, in part, by driving endothelial CD36 and lipoprotein lipase expression and facilitate FA transport across heart ECs. Combined Meox2 and Tcf15 haplodeficiency impaired FA uptake in heart ECs and reduced FA transfer to cardiomyocytes. In the long term, this combined haplodeficiency resulted in impaired cardiac contractility. CONCLUSIONS: Our findings highlight a regulatory role for ECs in FA transfer to the heart parenchyma and unveil 2 of its intrinsic regulators. Our insights could be used to develop new strategies based on endothelial Meox2/Tcf15 targeting to modulate FA transfer to the heart and remedy cardiac dysfunction resulting from altered energy substrate usage.

Gene polymorphisms and cytokine plasma levels as predictive factors of complications after cardiopulmonary bypass.

OBJECTIVE: Cardiopulmonary bypass remains associated with significant morbidity and mortality, in part caused by a systemic inflammatory response that is unpredictable and variable among patients. Several limited studies have suggested associations of cytokine plasma levels or gene polymorphisms with outcome after cardiopulmonary bypass. The present study was to determine the relationships between several circulating cytokines and their polymorphisms (single nucleotide polymorphisms), and the occurrence of postoperative clinical events in patients who underwent coronary artery bypass grafting under cardiopulmonary bypass. METHODS: Patients were genotyped for single nucleotide polymorphisms of LTA (Cys13Arg, +252A>G), TNF (-308G>A), IL6 (-597G>A, -572G>C, -174G>C), IL10 (-592C>A, c.∗117C>T), and APOE (Cys112Arg, Arg158Cys). Serum samples were collected preoperatively, immediately after cardiopulmonary bypass, and at different postoperative time points to measure cytokine serum levels by enzyme-linked immunosorbent assay. The clinical end point was the composite of postoperative death, low cardiac output syndrome, myocardial infarction, sepsis, and acute renal insufficiency. RESULTS: Single nucleotide polymorphisms IL6-572GC+CC/IL10-592CC were associated with the clinical end point (P=.032 and P=.009, respectively). In addition to preoperative clinical conditions, the other factor associated with the clinical end point was interleukin-10 plasma levels 24 hours after surgery (P=.017). On the basis of these results, a predictive model of postoperative complications after coronary artery bypass grafting was created. CONCLUSIONS: Our data suggest that focused genetic testing of the IL6-572G>C and IL10-592C>A single nucleotide polymorphisms might be a tool for identifying patients at the highest risk of poor tolerance to the inflammatory response to cardiopulmonary bypass and for implementing strategies to mitigate it, provided the generalization of these tests makes them reasonably affordable and thus favorably shifts their cost-to-benefit ratio.

Prognostic role of pro- and anti-inflammatory cytokines and their polymorphisms in acute decompensated heart failure.

BACKGROUND: Cytokines play an important role in chronic heart failure (HF), but little is known about their involvement in acute decompensated heart failure (ADHF). AIM: To evaluate the prognostic role of inflammatory cytokines in patients with ADHF. METHODS: Levels of interleukin (IL)-6, tumour necrosis factor alpha (TNF-alpha), IL-10 and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured in 423 patients with ADHF. In addition, appropriate cytokine gene polymorphisms were determined. Survival was followed up to 12 months, and prognostic factors were evaluated. RESULTS: Elevated levels of IL-6 and TNF-alpha were strongly associated with increased 12-month mortality (P<0.001 for both), whereas the level of IL-10 was predictive only of 6-month mortality (P<0.01). In multivariate analysis IL-6, chronic renal insufficiency, NT-proBNP, age/10 years' increase and TNF-alpha were identified as the most powerful predictors of 12-month mortality. Furthermore, high levels of both IL-6 and NT-proBNP were associated with >7-fold mortality. Cytokine gene polymorphisms were not associated with outcome. CONCLUSIONS: Circulating levels of pro-inflammatory cytokines IL-6 and TNF-alpha, and the level of an anti-inflammatory cytokine IL-10, but not their gene polymorphisms, provide novel and important prognostic information in patients with ADHF. Combining measurements of pro-inflammatory cytokines and NT-proBNP seems a promising tool in the prognostic assessment of these patients.

A cardiac myosin light chain kinase regulates sarcomere assembly in the vertebrate heart.

Marked sarcomere disorganization is a well-documented characteristic of cardiomyocytes in the failing human myocardium. Myosin regulatory light chain 2, ventricular/cardiac muscle isoform (MLC2v), which is involved in the development of human cardiomyopathy, is an important structural protein that affects physiologic cardiac sarcomere formation and heart development. Integrated cDNA expression analysis of failing human myocardia uncovered a novel protein kinase, cardiac-specific myosin light chain kinase (cardiac-MLCK), which acts on MLC2v. Expression levels of cardiac-MLCK were well correlated with the pulmonary arterial pressure of patients with heart failure. In cultured cardiomyocytes, knockdown of cardiac-MLCK by specific siRNAs decreased MLC2v phosphorylation and impaired epinephrine-induced activation of sarcomere reassembly. To further clarify the physiologic roles of cardiac-MLCK in vivo, we cloned the zebrafish ortholog z-cardiac-MLCK. Knockdown of z-cardiac-MLCK expression using morpholino antisense oligonucleotides resulted in dilated cardiac ventricles and immature sarcomere structures. These results suggest a significant role for cardiac-MLCK in cardiogenesis.

Progressive troponin I loss impairs cardiac relaxation and causes heart failure in mice.

Cardiac troponin I (TnI) knockout mice exhibit a phenotype of sudden death at 17-18 days after birth due to a progressive loss of TnI. The objective of this study was to gain insight into the physiological consequences of TnI depletion and the cause of death in these mice. Cardiac function was monitored serially between 12 and 17 days of age by using high-resolution ultrasonic imaging and Doppler echocardiography. Two-dimensional B-mode and anatomical M-mode imaging and Doppler echocardiography were performed using a high-frequency ( approximately 20-45 MHz) ultrasound imaging system on homozygous cardiac TnI mutant mice (cTnI(-/-)) and wild-type littermates. On day 12, cTnI(-/-) mice were indistinguishable from wild-type mice in terms of heart rate, atrial and LV (LV) chamber dimensions, LV posterior wall thickness, and body weight. By days 16 through 17, wild-type mice showed up to a 40% increase in chamber dimensions due to normal growth, whereas cTnI(-/-) mice showed increases in atrial dimensions of up to 97% but decreases in ventricular dimensions of up to 70%. Mitral Doppler analysis revealed prolonged isovolumic relaxation time and pronounced inversion of the mitral E/A ratio (early ventricular filling wave-to-late atrial contraction filling wave) only in cTnI(-/-) mice indicative of impaired LV relaxation. cTnI(-/-) mouse hearts showed clear signs of failure on day 17, characterized by >50% declines in cardiac output, ejection fraction, and fractional shortening. B-mode echocardiography showed a profoundly narrowed tube-like LV and enlarged atria at this time. Our data are consistent with TnI deficiency causing impaired LV relaxation, which leads to diastolic heart failure in this model.

Gene therapy in the treatment of heart failure.

Heart failure is a major cause of morbidity and mortality in contemporary societies. Although progress in conventional treatment modalities is making steady and incremental gains to reduce this disease burden, there remains a need to explore new and potentially therapeutic approaches. Gene therapy, for example, was initially envisioned as a treatment strategy for inherited monogenic disorders. It is now apparent that gene therapy has broader potential that also includes acquired polygenic diseases, such as heart failure. Advances in the understanding of the molecular basis of conditions such as these, together with the evolution of increasingly efficient gene transfer technology, has placed congestive heart failure within reach of gene-based therapy.

Upregulation of KCNE1 induces QT interval prolongation in patients with chronic heart failure.

BACKGROUND: Prolongation of the action potential duration (APD) is observed in ventricular myocytes isolated from the failing heart. The rapid component (I(Kr)) and the slow component (I(Ks)) of the delayed-rectifier potassium current (I(K)) are major determinants of the APD, but less information is available on the genomic modulation of I(K) in the remodeled human heart. The aim of the current study was to examine the relationship between I(K) transcripts and QT interval in surface electrocardiogram in patients with chronic heart failure (CHF). METHODS AND RESULTS: Total RNA was extracted from right ventricle endomyocardial biopsy samples in 21 CHF patients (age: 53+/-4 years, mean +/- SEM). The KCNH2 and KCNQ1 levels did not differ significantly between controls (New York Heart Association (NYHA) I, n=10) and CHF patients (NYHA II or III, n=11), whereas the KCNE1 level was significantly higher in CHF patients than in controls (relative mRNA levels normalized to GAPDH expression: 6.16+/-0.31 vs 7.70+/-0.46, p<0.05). The KCNE1/KCNQ1 ratio was higher in CHF patients than in controls (0.92+/-0.02 vs 1.06+/-0.05, p<0.05) and the KCNE1-KCNQ1 ratio was positively correlated with QT interval (r=0.70, p<0.05). Increasing the KCNE1 concentration caused a shift in activation voltage and slowed the activation kinetics of the KCNE1-KCNQ1 currents expressed in Xenopus oocytes. Prolongation of the APD and decrease in I(Ks) with increasing the amount of KCNE1 concentration were well predicted in a computer simulation. CONCLUSIONS: In mild-to-moderate CHF patients, the relative abundance of KCNE1 compared to KCNQ1 genes, at least in part, might contribute to the preferential prolongation of QT interval through reducing the net outward current during the plateau of the action potential.

Cardiac dysfunction in the R6/2 mouse model of Huntington's disease.

Recent evidence suggests that mutant huntingtin protein-induced energetic perturbations contribute to neuronal dysfunction in Huntington's disease (HD). Given the ubiquitous expression of huntingtin, other cell types with high energetic burden may be at risk for HD-related dysfunction. Early-onset cardiovascular disease is the second leading cause of death in HD patients; a direct role for mutant huntingtin in this phenomenon remains unevaluated. Here we tested the hypothesis that expression of mutant huntingtin is sufficient to induce cardiac dysfunction, using a well-described transgenic model of HD (line R6/2). R6/2 mice developed cardiac dysfunction by 8 weeks of age, progressing to severe failure at 12 weeks, assessed by echocardiography. Limited evidence of cardiac remodeling (e.g. hypertrophy, fibrosis, apoptosis, beta(1) adrenergic receptor downregulation) was observed. Immunogold electron microscopy demonstrated significant elevations in nuclear and mitochondrial polyglutamine presence in the R6/2 myocyte. Significant alterations in mitochondrial ultrastructure were seen, consistent with metabolic stress. Increased cardiac lysine acetylation and protein nitration were observed and were each significantly associated with impairments in cardiac performance. These data demonstrate that mutant huntingtin expression has potent cardiotoxic effects; cardiac failure may be a significant complication of this important experimental model of HD. Investigation of the potential cardiotropic effects of mutant huntingtin in humans may be warranted.

A quantitative gene expression profile of matrix metalloproteinases (MMPS) and their inhibitors (TIMPS) in the myocardium of patients with deteriorating heart failure requiring left ventricular assist device support.

BACKGROUND: Mechanisms underlying the rapid deterioration of heart failure patients who subsequently require left ventricular assist device (LVAD) support are poorly understood. Matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) play a key role in myocardial remodelling and heart failure. We hypothesized that MMP and TIMP expression would be altered in these patients. METHODS: Quantitative polymerase chain reaction was used to measure myocardial messenger RNA levels of MMP1 to MMP14, TIMP1 to TIMP4, collagen I and collagen III in 24 dilated cardiomyopathy (DCM) patients with deteriorating clinical status who required LVAD support (LVAD Group) and in 7 stable DCM patients undergoing transplantation without need for LVAD support (Tx Group). RESULTS: Levels of MMP1, MMP8 and TIMP4 were higher in the LVAD Group compared with the Tx Group (188% +/- 141%, 646% +/- 432%, and 66% +/- 33% higher, respectively, p < 0.05) whereas MMP2, MMP9, MMP10, MMP11, and MMP14 levels were similar. MMP3, MMP7, MMP12, and MMP13 were undetectable. All TIMPs were generally higher in the LVAD group, but only TIMP4 reached significance. Collagen I and III were not altered. We tested for correlations between MMP and TIMP expression with myocardial cytokine levels. MMP8 correlated positively with interleukin-6 and interleukin-1beta, suggesting a link between cytokines and MMPs in these patients. CONCLUSIONS: The data show that high myocardial collagenase (MMP1 and MMP8) expression without compensatory changes in collagen or TIMP expression is a feature of patients requiring LVAD support. This may be linked in part to elevated cytokine expression and suggests collagenase activity may be an important therapeutic target in deteriorating heart failure.

Beta2-adrenergic receptor genotype and pulmonary function in patients with heart failure.

OBJECTIVE: Chronic heart failure (CHF) is associated with neurohumoral activation and decrements in pulmonary function (PF). The beta2-adrenergic receptor (ADRB2) modulates airway smooth muscle tone and influences lung fluid clearance. Common polymorphisms of the ADRB2 are associated with differences in ADRB2 function and therefore could differentially influence PF in patients with CHF. METHODS: We studied baseline PF according to genetic variations of the ADRB2 at amino acid 16 (ie, arginine [Arg] or glycine [Gly]) in 126 CHF patients (mean [+/- SEM] age, 56 +/- 1 years; left ventricular ejection fraction [LVEF], 29 +/- 1%; body mass index [BMI], 28 +/- 0.4 kg/m2) and in 100 healthy control subjects (mean age, 50 +/- 2 years; LVEF, 63 +/- 0.7%; BMI, 25 +/- 0.3 kg/m2). RESULTS: Venous epinephrine levels did not differ between CHF patients and control subjects or across genotype groups; however, norepinephrine levels were higher in CHF patients and was greater in ArgArg patients compared to GlyGly patients (p < 0.05). PF did not differ according to genotype in control subjects; however, CHF patients who were homozygous for Arg had reduced PF relative to heterozygotes or those subjects who were homozygous for Gly (vital capacity: ArgArg group, 82 +/- 3% predicted; ArgGly group, 92 +/- 2% predicted; GlyGly group, 93 +/- 2% predicted; FVC: ArgArg group, 77 +/- 3% predicted; ArgGly group, 89 +/- 2% predicted; GlyGly group, 90 +/- 2% predicted; FEV1: ArgArg group, 75 +/- 4% predicted; ArgGly group, 86 +/- 3% predicted; GlyGly group, 87 +/- 2% predicted; diffusing capacity of the lung for carbon monoxide: ArgArg group, 76 +/- 4% predicted; ArgGly group, 83 +/- 2% predicted; GlyGly group, 85 +/- 2% predicted; p < 0.05). In addition, there was a modest correlation between mitral valve inflow deceleration time and PF in CHF patients (r = 0.42; p < 0.01), but not in control subjects. CONCLUSIONS: These data suggest that genetic variation of the ADRB2 is associated with differences in PF in CHF patients but not in healthy subjects, which may be related to an increased susceptibility of the homozygous Arg subjects to agonist-mediated desensitization of ADRB2s in the lungs, or related to an influence of this polymorphism on cardiac diastolic properties.

Redefining heart failure: the utility of genomics.

In this era of genomics, new technologies and the information that they generate have a wide range of potential applications to heart failure. Though there has not been widespread practical use of genomic information in everyday practice, there are many examples of how this information is beginning to transform the way we look at disease states in terms of diagnosis, prognosis, and treatment. The experience of oncology and other fields helps inform the heart failure field of not only the use of this information in investigating diagnosis, prognosis, and treatment response, but the reciprocal nature of this information. This information can be clinically useful (for instance, predicting treatment response) as well as further drive laboratory investigation (teasing out the biological pathways in non-responders to treatment can be a focus of new drug discovery); this is the essence of translational medicine. We believe that this is a good time to review where new technologies and information they generate can be placed into our classic understanding of heart failure: that is how we might redefine cardiomyopathy given our new information. Here we will review genomic evidence to date and how it can and may be considered in the evaluation and management of cardiomyopathies.

The role of adrenergic receptor polymorphisms in heart failure.

The main function of the cardiac adrenergic system is to regulate cardiac work both in physiologic and pathologic states. A better understanding of this system has permitted the elucidation of its role in the development and progression of heart failure. Regardless of the initial insult, depressed cardiac output results in sympathetic activation. Adrenergic receptors provide a limiting step to this activation and their sustained recruitment in chronic heart failure has proven to be deleterious to the failing heart. This concept has been confirmed by examining the effect of beta-blockers on the progression of heart failure. Studies of adrenergic receptor polymorphisms have recently focused on their impact on the adrenergic system regarding its adaptive mechanisms, susceptibilities and pharmacological responses. In this article, we review the function of the adrenergic system and its maladaptive responses in heart failure. Next, we discuss major adrenergic receptor polymorphisms and their consequences for heart failure risk, progression and prognosis. Finally, we discuss possible therapeutic implications resulting from the understanding of polymorphisms and the identification of individual genetic characteristics.

The role of adrenergic receptor polymorphisms in heart failure

The main function of the cardiac adrenergic system is to regulate cardiac work both in physiologic and pathologic states. A better understanding of this system has permitted the elucidation of its role in the development and progression of heart failure. Regardless of the initial insult, depressed cardiac output results in sympathetic activation. Adrenergic receptors provide a limiting step to this activation and their sustained recruitment in chronic heart failure has proven to be deleterious to the failing heart. This concept has been confirmed by examining the effect of ß-blockers on the progression of heart failure. Studies of adrenergic receptor polymorphisms have recently focused on their impact on the adrenergic system regarding its adaptive mechanisms, susceptibilities and pharmacological responses. In this article, we review the function of the adrenergic system and its maladaptive responses in heart failure. Next, we discuss major adrenergic receptor polymorphisms and their consequences for heart failure risk, progression and prognosis. Finally, we discuss possible therapeutic implications resulting from the understanding of polymorphisms and the identification of individual genetic characteristics.