Elevated serum brain natriuretic peptide and matrix metalloproteinases 2 and 9 in Wilson's disease

Cardiac copper content and its relationship with heart physiology: Insights based on quantitative genetic and functional analyses using BXD family mice

Background

Copper (Cu) is essential for the functioning of various enzymes involved in important cellular and physiological processes. Although critical for normal cardiac function, excessive accumulation, or deficiency of Cu in the myocardium is detrimental to the heart. Fluctuations in cardiac Cu content have been shown to cause cardiac pathologies and imbalance in systemic Cu metabolism. However, the genetic basis underlying cardiac Cu levels and their effects on heart traits remain to be understood. Representing the largest murine genetic reference population, BXD strains have been widely used to explore genotype-phenotype associations and identify quantitative trait loci (QTL) and candidate genes.

Methods

Cardiac Cu concentration and heart function in BXD strains were measured, followed by QTL mapping. The candidate genes modulating Cu homeostasis in mice hearts were identified using a multi-criteria scoring/filtering approach.

Results

Significant correlations were identified between cardiac Cu concentration and left ventricular (LV) internal diameter and volumes at end-diastole and end-systole, demonstrating that the BXDs with higher cardiac Cu levels have larger LV chamber. Conversely, cardiac Cu levels negatively correlated with LV posterior wall thickness, suggesting that lower Cu concentration in the heart is associated with LV hypertrophy. Genetic mapping identified six QTLs containing a total of 217 genes, which were further narrowed down to 21 genes that showed a significant association with cardiac Cu content in mice. Among those, Prex1 and Irx3 are the strongest candidates involved in cardiac Cu modulation.

Conclusion

Cardiac Cu level is significantly correlated with heart chamber size and hypertrophy phenotypes in BXD mice, while being regulated by multiple genes in several QTLs. Prex1 and Irx3 may be involved in modulating Cu metabolism and its downstream effects and warrant further experimental and functional validations.

Cardiac involvement in Wilson disease: Review of the literature and description of three cases of sudden death

Wilson disease (WD) is a rare genetic condition that results from a build-up of copper in the body. It requires life-long treatment and is mainly characterized by hepatic and neurological features. Copper accumulation has been reported to be related to the occurrence of heart disease, although little is known regarding this association. We have conducted a systematic review of the literature to document the association between WD and cardiac involvement. Thirty-two articles were retained. We also described three cases of sudden death. Cardiac manifestations in WD include cardiomyopathy (mainly left ventricular (LV) remodeling, hypertrophy, and LV diastolic dysfunction, and less frequently LV systolic dysfunction), increased levels of troponin, and/or brain natriuretic peptide, electrocardiogram (ECG) abnormalities, and rhythm or conduction abnormalities, which can be life-threatening. Dysautonomia has also been reported. The mechanism of cardiac damage in WD has not been elucidated. It may be the result of copper accumulation in the heart, and/or it could be due to a toxic effect of copper, resulting in the release of free oxygen radicals. Patients with signs and/or symptoms of cardiac involvement or who have cardiovascular risk factors should be examined by a cardiologist in addition to being assessed by their interdisciplinary treating team. Furthermore, ECG, cardiac biomarkers, echocardiography, and 24-hours or more of Holter monitoring at the diagnosis and/or during the follow-up of patients with WD need to be evaluated. Cardiac magnetic resonance imaging, although not always available, could also be a useful diagnostic tool, allowing assessment of the risk of ventricular arrhythmias and further guidance of the cardiac workup.

Cardiac assessment in Wilson's disease patients based on electrocardiography and echocardiography examination

INTRODUCTION

Wilson's disease (WD) is a rare genetic disorder that leads to impairments in copper metabolism. Patients principally exhibit liver and neuropsychiatric symptoms, but because copper also accumulates in all body organs, other (typically milder) clinical symptoms can occur. To date, cardiac involvement has not been thoroughly investigated in patients with WD. This study aimed to evaluate heart structure and function in patients with WD with commonly available diagnostic methods.

MATERIAL AND METHODS

We compared 125 WD patients with an age- and sex-matched control group. Patients with WD were grouped according to their dominant symptoms - neurologic or hepatic. All subjects underwent clinical, electrocardiographic (ECG), and echocardiographic examinations.

RESULTS

All subjects had sinus rhythm on electrocardiography. The only ECG parameter that differed between patients with WD and the control group was the QRS prolongation (92.0 vs. 86.4 ms; p < 0.05). On echocardiography patients with WD exhibited more hypertrophy in the left ventricle than controls (posterior wall in diastole: 1.0 vs. 0.93; p < 0.01) and the left ventricle hypertrophy was more pronounced in the neurologic than in the hepatic subgroup (1.05 vs. 0.96 cm; p < 0.01). Left ventricular systolic function was similar in the WD and the control group (ejection fraction: 67.5% vs. 67.7%). On tissue Doppler echocardiography patients with WD demonstrated slowing of myocardial relaxation, which was more evident in the neurologic group.

CONCLUSIONS

Heart involvement in WD was manifested mainly by mild left ventricular hypertrophy and subclinical changes in diastolic function, particularly in the patients with the neurologic form of disease.