Copper deficiency alters collagen types and covalent cross-linking in swine myocardium and cardiac valves

The utility of electrocardiography and echocardiography in copper deficiency-induced cardiac damage in goats

Copper deficiency (CuD) is a common mineral disorder in ruminants, which causes histomorphological changes in the heart due to disturbances in copper-dependent metalloenzymes. However, alterations in the measurable cardiac parameters during CuD have not been studied in ruminants, especially in goats. Therefore, the current study aimed to investigate longitudinally the potential role of electrocardiography (ECG) and echocardiography to detect the CuD-induced cardiac damage at different time intervals and concomitantly highlighting the impact of CuD on specific hemato-biochemical parameters and histological cardiac disruption in goats. Eight Shiba goats were included and divided into two equal groups; copper adequate (CuA) as a control and copper-deficient (CuD) that supplemented with copper-chelating agents (sulfur 3 g/kg DM and molybdenum 40 mg/kg DM). The hemato-biochemical analysis, ECG assessment at the base apex lead, and right-side echocardiography were performed just before the experimental onset (T0), and later on at two-time intervals after existing of CuD, at the fifth (T5) and seventh (T7) months. Necropsy and histopathological examination of the heart were performed at the end of the experiment. In the CuD group, the heart dimensions at T5 and T7 showed significant increase in QRS duration, ST-segment duration, the left atrial area in systole, left ventricular diameter and volume in diastole, stroke volume, and cardiac output compared with CuA (P < 0.05). Also, myocardial degeneration, necrosis, and fibrosis were evidenced with a concurrent increase of plasma creatine kinase, lactate dehydrogenase, aspartate aminotransferase, and cardiac troponin I (P < 0.05). In conclusion, CuD disturbs hemato-biochemical parameters and results in myocardial damage and cardiac dilatation that increases some ECG and echocardiographic parameters without development of systolic dysfunction. The ECG and echocardiography can potentially detect cardiac changes in long-lasting CuD in goats.

Proline-dependent regulation of collagen metabolism

This review is focused on recent data on the role of proline (Pro) in collagen biosynthesis and cellular metabolism. It seems obvious that one of the main substrates for collagen biosynthesis Pro is required to form collagen molecule. The question raised in this review is whether the Pro for collagen biosynthesis is synthesized “de novo”, comes directly from degraded proteins or it is converted from other amino acids. Recent data provided evidence that extracellular Pro (added to culture medium) had significant, but relatively little impact on collagen biosynthesis in fibroblasts (the main collagen synthesized cells) cultured in the presence of glutamine (Gln). However, extracellular Pro drastically increased collagen biosynthesis in the cells cultured in Gln-free medium. It suggests that Pro availability determines the rate of collagen biosynthesis and demand for Pro in fibroblasts is predominantly met by conversion from Gln. The potential mechanism of this process as well as possible implication of this knowledge in pharmacotherapy of connective tissue diseases is discussed in this review.

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.

In spontaneously hypertensive rats alterations in aortic wall properties precede development of hypertension

In hypertension arterial wall properties do not necessarily depend on increased blood pressure alone. The present study investigates the relationship between the development of hypertension and thoracic aortic wall properties in 1.5-, 3-, and 6-mo-old spontaneously hypertensive rats (SHR); Wistar-Kyoto rats (WKY) served as controls. During ketamine-xylazine anesthesia, compliance and distensibility were assessed by means of a noninvasive ultrasound technique combined with invasive blood pressure measurements. Morphometric measurements provided in vivo media cross-sectional area and thickness, allowing the calculation of the incremental elastic modulus. Extracellular matrix protein contents were determined as well. Blood pressure was not significantly different in 1.5-mo-old SHR and WKY, but compliance and distensibility were significantly lower in SHR. Incremental elastic modulus was not significantly different between SHR and WKY at this age. Media thickness and media cross-sectional area were significantly larger in SHR than in WKY, but there was no consistent difference in collagen density and content between the strains. Blood pressure was significantly higher in 3- and 6-mo-old SHR than in WKY, and compliance was significantly lower in SHR. The findings in this study show that in SHR, in which hypertension develops over weeks, alterations in functional aortic wall properties precede the development of hypertension. The decrease in compliance and distensibility at a young age most likely results from media hypertrophy rather than a change in intrinsic elastic properties.

Marginal copper and high fat diet produce alterations in electrocardiograms and cardiac ultrastructure in male rats

This study investigated whether a high fat diet in tandem with a marginal copper (Cu) diet exerts deleterious effects on copper status, cardiac morphology, and electrophysiology compared to a low-fat marginal copper diet. Male weanling Long-Evans rats were fed diets containing either marginal copper (42.5 mumol/kg) or adequate copper (97.6 mumol/kg), and low fat (50.0 g/kg) or high fat (150.0 g/kg) diet for 12 wk in a 2 x 2 factorial design. To simulate the western diet, fat was composed of a 1:2 polyunsaturated:saturated fatty acids using a coconut and corn oil mixture. High dietary fat increased liver Cu concentration. Marginal copper diets decreased liver Cu,Zn-superoxide dismutase activity. Dietary copper and fat level had no effect on volume densities of mitochondria and myofibril. However, lower mitochondrial pathologic scores were observed in the rats consuming the high fat diets. Marginal copper high fat diet prolonged atrial electric depolarization (PR) and ventricular electric depolarization and repolarization (QT) intervals. This study provided direct evidence that a high fat diet can exert detrimental effects on cardiac ultrastructure and lead to alterations in electrocardiograms. The combination of marginal copper-high fat diet appears to alter cardiac electric conductivity. Longer term studies should provide information more relevant to clinical situations and morphologic changes.

Influence of nicotine on myocardial stiffness and fibrosis during chronic ethanol use

Cardiomyopathy related to ethanol abuse is often accompanied by cigarette use. To examine if the major cardioactive component may intensify the abnormal function and composition induced by chronic ethanol, nicotine was administered orally, 2.5 mg bid, to a canine model receiving 36% of calories as ethanol for 6 months (group III). These animals were compared with group II receiving ethanol alone, group IV on nicotine alone, and controls (group I). In the intact, ventilated, anesthetized dog, left ventricular pressures and volumes were measured before and after dextran infusion and related to left ventricular collagen alterations. Basal heart rate, aortic pressure, and ejection fraction were comparable with controls. End-diastolic pressure and diastolic chamber stiffness (KPV) were significantly higher in the basal state and during dextran infusion in the three experimental groups, compared with group I. The increment was largest in the ethanol-nicotine group. Analysis of left ventricular myocardium revealed a rise of collagen concentrations in all three experimental groups, with an interstitial distribution on histochemical examination. Moreover, determination of advanced glycosylation endproducts, as a measure of alterations in collagen cross-links, revealed higher concentrations versus controls. The greater increase of diastolic stiffness in the nicotine-ethanol group occurred despite a similar concentration of fluorescent products as group II. Because the former had a larger increase of collage concentration, total cross-linked collagen content was presumably greater after the combined use of nicotine-ethanol. Thus, nicotine in relatively high dose when combined with ethanol, elicited a modest further increase in the left ventricular chamber stiffness and collagen concentration.