Impact of summer heat waves on key parameters of oxidative stress in patients with coronary artery disease

Abstract

To assess the impact of summer heat waves on key parameters of oxidative stress in patients with coronary heart disease. We included 30 male patients aged 5213 years with stable angina pectoris of IIIII functional class with at least one coronary artery stenosis proved by angiography (ischemic group) in comparison with 10 male patients aged 487 years with no angiographic sings of significant coronary stenosis and without angina manifestation (non-ischemic group). The following parameters were studied: activity of superoxide dismutase (Cu,Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), the level of malondialdehyde (MDA) and MDA-modified low-density lipoproteins (MDA-LDL). The analysis of indicators was performed at normal average daily temperature (daytime temperature not higher than 20С) and after a heat wave (daytime temperature above 27C for more than 2 consecutive days). Our study revealed the decrease of CAT and GSH-Px activities with increased activity of Cu,Zn-SOD in both groups after the heat wave. At the same time we observed accumulation of MDA and increased MDA-LDL level in both groups. Initially ischemic patients showed significantly increased level of CAT and GSH-Px activity compared to the non-ischemic group, while it was no difference in activity of Cu,Zn-SOD and MDA and MDA-LDL level. We observed significant reduce of Cu,Zn-SOD activity in ischemic patients compared to non-ischemic group with no significant differences in all other studied parameters of oxidative stress after heat wave. Changes in the key parameters of oxidative stress in patients with ischemic heart disease during summer heat waves are comparable to those in patients without ischemia, however significantly greater inhibition of GSH-Px activity and significantly lower increase in Cu,Zn-SOD activity was noted. These results may indicate misregulation of free radical processes in patients with ischemic heart decease.