Effect of Bone Marrow-Derived Mesenchymal Stem Cells on Ischaemic-Reperfused Hearts in Adult Rats with Established Chronic Kidney Disease

BACKGROUND AND OBJECTIVES: Bone marrow-derived mesenchymal stem cells (BM-MSCs) are adult multipotent non-haematopoietic stem cells that have regeneration potential. The current study aimed to detect the ability of BM-MSCs to improve kidney and cardiac functions in adult rats with established chronic kidney disease. METHODS: Rats were divided into sham-operated control, untreated sub totally nephrectomised and treated sub totally nephrectomised groups. Body weight, kidney and cardiac tissue weights, plasma creatinine and urea levels and arterial blood pressure were measured. ECG was recorded, and an in vitro isolated heart study was performed. Results: Stem cell treatment decreased the elevated plasma creatinine and urea levels and decreased systolic, diastolic and mean arterial blood pressure values. These changes were accompanied by a decrease in glomerular hypertrophy with apparent normal renal parenchyma. Additionally, BM-MSCs shortened Q-To and Q-Tc intervals, all time to peak tension values, the half relaxation value at 30 min of reperfusion and the contraction time at 15 and 30 min of reperfusion. Moreover, stem cell treatment significantly increased the heart rate, QRS voltage, the peak tension at the 15- and 30-min reperfusion time points and the peak tension per left ventricle at the 30-min reperfusion time point compared to the pre-ischaemia baseline. BM-MSCs resolve inter muscular oedema and lead to the re-appearance of normal cardiomyocytes. This improvement occurs with the observations of BM-MSCs in renal and heart tissues. CONCLUSIONS: BM-MSCs can attenuate chronic kidney disease progression and the associated cardiac electrophysiological and inotropic dysfunction.

Development and Evaluation of a New Apparatus for Continuous Perfusion of Isolated Perfused Pig Heart

To develop a better model of isolated perfused heart, a new apparatus of "coronary artery cannula- fixed-in-aortic tube" was developed for continuous normothermic perfusion and compared to the Casalis apparatus with cold ischemia. Eight mongrel pigs with the body weight of 18 to 24 kg were divided half into two groups.All the continuous perfusion experimental hearts resumed a spontaneous heart beat and stabilized earlier than the control hearts without the need of defibrillator or pacemaker, indicating no reperfusion injury on the heart. All the experimental hearts did not show fibrillation nor stopped beating during the entire experiment, whereas the control hearts fibrillated. Two control hearts stopped beating, and only one of the two survived with the help of pacemaker.The coronary systolic, diastolic, and mean pressures were more stable with low variation in the experimental hearts than the cold ischemic control hearts. The experimental hearts consumed more oxygen than the control hearts, indicating more cardiac output.According to these results, the continuous normothermic perfusion method by the new cannula, even though with a short-period of hypothermic perfusion, provided better myocardial protection than the cold ischemia.

Effect of Hypoxia on Antegrade and Retrograde Atrioventricular Conduction in Isolated Perfused Heart

PURPOSE: Cyanotic congenital heart diseases patients are in a state of hypoxia since birth. In general, hypoxia delays atrioventricular conduction. The atrioventricular node in such a hypoxic condition would have a different function, and some possibility for arrhythmia. The authors studied atrioventricular nodal function during hypoxia to elucidate the relationship between hypoxia and arrhythmia, including atrioventricular node in terms of cardiac tissue level. METHODS: After extraction of an adult rabbit heart under pentobarbital anesthesia, the heart was retrogradely perfused through the aorta with graded hypoxic Krebs' solution(100, 70, and 50% oxygen). The intracardiac electrocardiograms were obtained by a custom-made programmed stimulation at basic cyde length 40ms antegradely and retrogradely. All the data was analysed at His-electrogram and conduction time. Refractory periods and Wenckebach cycling length were determined. RESULTS: During antegrade conduction, the fast AV nodal conduction was prolonged and the slow conduction shortened, resulting in decreased compliance of the AV nodal conduction with graded hypoxia. The His-Purkinje system also showed a similar result. Among the refractory periods, only the AV nodal effective refractory period was prolonged with hypoxia. Wenckebach cycle length was sensitive to hypoxia, especially for retrograde conduction. CONCLUSION: Because the AV conduction during hypoxia was characterized by decreased AV conduction compliance, prolonged AV nodal effective refractory period, and sensitive Wenckebach cyding length, hypoxia would not seem to be a special risk for arrhythmia, including AV node.

Effects of rhomotoxin on electrophysiologic parameters in rabbit heart / 中国临床药理学与治疗学

Aim To study effects of rhomotoxin (Rh) on electrophysiologic parameters in rabbit heart. Methods The rabbit hearts in vivo were injected with Rh 12.5 ?g?kg-1 , 25 ?g?kg-1 or saline iv respectively and the isolated rabbit hearts were perfused by Krebs-Henseleit(K-H) perfusion liquid containing Rh 0.34 ?mol?L-1 or 0.68 ?mol?L-1. The electrophysiologic parameters were observed before and after drug adminitration.Results At 20,40,60 and 80 min after injection of Rh 12.5 ?g?kg-1 iv,the VDT,ERP and RRP had no significant changes; but at 20,40,60 and 80 min after injection of Rh 25 ?g?kg-1 iv a significant prolongation of ERP and (or) RRP was found (P