Date Published: March 18, 2018
Publisher: Tabriz University of Medical Sciences
Author(s): Jila Haghi, Tahereh Eteraf-Oskouei, Moslem Najafi.
Purpose: In the present study, postconditioning effect of fructose against ischemia/reperfusion (I/R)-induced arrhythmias and infarct size were investigated in isolated rat heart.
Despite the major advances in the identification and treatment of cardiovascular diseases, myocardial infarction (MI) continues to be a major health problem.1 Other important disorders such as arrhythmias, are also created by MI.2 In this regard, size of the heart infarction area is an important determinant for mortality after MI.3 Restoring blood flow to ischemic myocardium leads to ischemia/reperfusion (I/R) injury.4 Improvement of cardiac function in reperfusion mainly depends on the duration of ischemia. On the other hand, reperfusion itself causes disorders that include myocardial stunning, re-flow phenomenon, cardiac arrhythmias, necrosis and apoptosis of cardiomyocytes.5,6
Effects of post-ischemic administration of fructose on reperfusion-induced cardiac arrhythmias after 30 min zero flow global ischemia are summarized in Table 1. Perfusion of glucose-free K/H solution in which glucose was replaced with 12, 24 and 48 mM of fructose, had no statistically significant inhibitory effect on the total number of VEBs compared to the control group. Similarly, administration of normal K/H solution containing glucose plus 12, 24 and 48 mM of fructose did not produce significant reduction in the number of VEBs (Figure 1). In addition, statistical comparison did not show any significant difference between the control and all treatment groups on Rev VF duration in both sets of experiments (Figure 2).
Coronary heart disease is estimated to be the leading cause of death worldwide by 2030.32 In spite of advances in treating ischemic heart diseases in the past three decades, acute MI is a major cause of death in developed countries.33 Reperfusion (restoration of blood flow to ischemic tissue) after an ischemic period can be more fatal than ischemia itself due to production of destructive free radicals and calcium overloading, etc.34
In general, findings of this study showed that administration of high concentrations of fructose alone or together with normal glucose, reduces the volume and percentage of infarct size in isolated hearts after global ischemia. However, it does not have a significant inhibitory effect against reperfusion-induced dangerous cardiac arrhythmias such as VF and VT. Probably, fructose prevents necrosis and death of cardiomyocytes by supplying adequate ATP for cardiac functions during I/R, and then reduces infarct size.
The present work was supported by the Research Affairs of Tabriz University of Medical Sciences, Tabriz, Iran. This article is based on a thesis submitted for Pharm D degree (No.3671) in Faculty of Pharmacy, Tabriz University of Medical Sciences.
All the experiments were carried out under ethical guidelines of Tabriz University of Medical Sciences, for the care and use of laboratory animals (National Institutes of Health Publication No 85-23, revised 1985).
The authors report no conflicts of interest.