Correlation among water content, left ventricular function, coronary blood flow, and myocardial metabolism after hypothermic ischemic cardiac arrest

Xinshuitong Capsule extract attenuates doxorubicin-induced myocardial edema via regulation of cardiac aquaporins in the chronic heart failure rats

Doxorubicin (Dox), an effective antineoplastic drug, was limited use for cardiotoxicity. Xinshuitong Capsule (XST), a patented herbal formula, showed desirable beneficial effects in the treatment of chronic heart failure (CHF) patients. However, the drug on Dox-induced cardiotoxicity remains unclear. Ninety male Sprague-Dawley rats were randomized into two groups: 15 rats were selected as the normal group and 75 rats were injected intraperitoneally with Dox to establish CHF rat models, the success ones were randomly divided into five groups: low XST (LXST), medium XST (MXST) or high XST (HXST) (4.9, 9.8, or 19.6 g/kg d) administrated intragastrically twice a day for 4 weeks, with the captopril-treated group and the model group as comparison. The model group showed the cardiac functions generally impaired, and CHF mortality rate higher (47%) than those in the XST-treated groups (averaged 24%, P < 0.05). Compared with XST-treated groups, myocardial remodeling, inflammation and desarcomerization, and higher water content more severe in the cardiac tissue in the model group (P < 0.05), which was associated with higher expressions of mRNA or protein levels of AQP1, 4 and 7. Dox-impaired cardiac functions, cardiac remodeling and myocardial edema could be dose-dependently reverted by XST treatment. XST could inhibit AQP1, 4 and 7 at mRNA levels or at protein levels, which was associated with the attenuation of myocardial edema and cardiac remodeling, decreasing the ventricular stiffness and improving the cardiac functions and rats' survival. AQPs is involved in cardiac edema composed one of the mechanisms of Dox-induced cardiotoxicity, XSTvia inhibition of AQPs relieved the Dox-induced side effects.

Left ventricular myocardial edema. Lymph flow, interstitial fibrosis, and cardiac function

We hypothesized that both acute and chronic accumulation of myocardial interstitial edema (extravascular fluid [EVF]) would compromise cardiac function. We also postulated that excess fluid within the myocardial interstitial space would potentiate interstitial fibrosis, thus further compromising function. Dogs were divided into three groups: 1) control, 2) chronic pulmonary hypertensive with right heart failure, and 3) chronic arterial hypertensive. The quantity of EVF, expressed as the unitless blood-free (wet weight-dry weight)/dry weight ratio, and interstitial fibrosis (collagen content) were determined and correlated with cardiac function at baseline and after acute elevation of coronary venous pressure and reduction of cardiac lymph flow. Control EVF was 2.90 +/- 0.20 (mean +/- SD), which increased to 3.45 +/- 0.16 after acute (3-hour) elevation of coronary sinus pressure. This EVF significantly compromised cardiac function. The EVF in chronically hypertensive dogs and in dogs with chronic right heart pressure elevations was 3.50 +/- 0.30 and 3.50 +/- 0.08, respectively. End-diastolic left ventricular interstitial fluid pressure increased from a control value of 14.9 +/- 3.1 (at EVF = 2.9) to 24.8 +/- 3.7 (at EVF = 3.5). An EVF of 3.5 produced approximately 30% reduction of the heart's ability to maintain cardiac output at a left atrial pressure of 15 mm Hg. The compromised function in these chronic models is exacerbated after acute elevation of coronary venous pressure and reduction of cardiac lymph flow. Collagen levels were elevated by at least 20% in the chronic hypertensive dogs and in the nonhypertrophied left ventricles of dogs with chronic right heart pressure elevation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of intracoronary infusion of histamine or compound 48/80 on coronary vascular permeability and myocardial fluid balance

This study was undertaken to determine if coronary vascular permeability (CVP) increases and if myocardial edema develops in the canine heart after local exposure to histamine. Histamine (50 or 15 micrograms/min) or compound 48/80 (0.1-0.2 mg/kg) was infused into the left anterior descending coronary artery (LAD) of open-chest dogs, and changes in CVP were determined by comparing prenodal cardiac lymph flow (Q1) and lymph-to-plasma protein concentration ratio (C1/Cp) before and during histamine or compound 48/80 treatment. CVP increased in most, but not all, experiments with both doses of histamine as indicated by simultaneous increases in both Q1 and C1/Cp. The injection of compound 48/80 into the LAD of four dogs caused unequivocal increases in CVP in only one experiment. Compared with the effect of histamine on the forelimb, the average increases in Q1 and C1/Cp were not large with either histamine or compound 48/80, which suggests that the increases in CVP were relatively small. Moreover, edema did not develop. These results indicate that the coronary microvasculature of the intact dog heart is relatively insensitive to increases in permeability produced by histamine. Furthermore, the release of histamine from myocardial mast cells would not be expected to play a major role in the myocardial edema that develops under various pathological conditions.

Effects of catecholamines on myocardial viability in early reperfusion following hypothermic global ischemia in dogs--comparison between epinephrine and dobutamine

Attempts were made to define the effects of epinephrine and dobutamine on the myocardium during early reperfusion for 60 minutes following hypothermic global ischemia at a myocardial temperature of 28 degrees C for 60 minutes under cardiopulmonary bypass. Ischemia was induced by cross-clamping the dog aorta. Epinephrine (0.1 microgram/kg/min) and dobutamine (5 micrograms/kg/min) were given throughout the reperfusion period by intravenous drip infusion, a control group was treated with saline infusion. Comparison of hemodynamic parameters was made before cardiopulmonary bypass, and at 30 and 60 minutes of reperfusion. Epinephrine and dobutamine significantly increased stroke volume index, left ventricular stroke work index and tissue calcium content compared with saline, however, myocardial water content was only slightly higher in the group given saline, compared with the other two groups. Myocardial mitochondrial membranes and cristae were slightly damaged and creatine phosphate content was reduced. Ultrastructural integrity was related to myocardial tissue calcium content, with a significant negative correlation. These results suggest that epinephrine (0.1 microgram/kg/min) will improve stroke volume index and left ventricular stroke work index, as does dobutamine (5 micrograms/kg/min), however, both agents had a minimal effect on reducing myocardial morphological and biochemical integrity, although catecholamines have detrimental effects on the myocardium in early reperfusion following ischemia.

Alterations in cardiac composition with weight reduction in the obese rat

Alterations in myocardial composition associated with obesity and weight reduction have been examined in the spontaneously obese rat. When compared to values obtained from obese animals, body weight reduction was associated with a significant decrease in body fat, heart weight, and absolute left ventricular mass. Compositional analysis indicated that protein, lipid, and water together accounted for approximately 98% of total heart weight, and that while each component decreased with weight reduction, decreased myocardial water content represented the largest contribution to the reduced total heart weight. These data therefore suggest that the cardiomegaly of obesity is contributed to by specific changes in myocardial composition which can be altered through body weight reduction.