MORPHOLOGICAL AND FUNCTIONAL MYOCARDIAL ABNORMALITIES IN THE CHORNOBYL NPP ACCIDENT CLEAN-UP WORKERS OF «IODINE» PERIOD HAVING GOT TYPE 2 DIABETES MELLITUS.

OBJECTIVE

Evaluation of morphological and functional myocardial abnormalities in the Chornobyl NPP (ChNPP)accident clean-up workers (ACUW) of the «iodine» period exposed to ionizing radiation at a young age and havinggot the type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

The ChNPP ACUW of «iodine» period (n=111) exposed to ionizing radiation (IR) at a young age(18-35 years) were involved in the study. Subjects having got the T2DM were included in study Group I (n = 66), per-sons with normal glucose challenge test were selected as a comparison Group II (n = 45). External radiation doses (ERD)ranged from 10 to 860 mSv. The Group III (clinical control) included persons having got the T2DM with no radiationexposure in a history (n=20). Group IV was the normative one. There was no statistical difference between the groups inage, sociodemographic characteristics and level of education. Echocardiography and cardiac Doppler sonography wereperformed in one- and two-dimensional regimens according to the recommendations of the European Association ofEchocardiography. Total adiponectin and proinflammatory cytokine (TNF-α and IL-6) concentrations were assayed by theimmunoenzyme method. Statistical processing of data was carried out using the Microsoft® Exel 2002 software.

RESULTS

Myocardial remodeling in the ChNPP ACUW of a «iodine» period having the T2DM occurred through a sig-nificant increase of its linear parameters. Volumetric parameters (EDV, ESV and their indexes) were within maximumpermissible limits significantly exceeding however the values in the Group IV. There was aт increase in myocardialmass of the left ventricle and its indices with the formation of structural-geometric abnormalities, mainly in theform of concentric hypertrophy with a decrease in the myocardial contractile capacity. There was no differences ofthe vast majority of key morphometric parameters of myocardium in the dose subgroups, while in persons with ERD> 500 mSv the incidence of serious left ventricular hypertrophy (LVMMI > 149 g/m2) significantly exceeded thisvalue in individuals with lower ERD. At a maximum ERD the more intense fibroplastic processes were observed inmyocardium [a significant increase in the interstitial collagen volumetric fraction (ICVF)] as compared to the caseswith ERD up to 50 mSv. Intensification of myocardial fibroblastic processes occurred in the comparizin group andgroup off clinical control. In combination with concentric myocardial hypertrophy this may lead to an increased riskof cardiovascular complications. Strong negative correlation was revealed between the parameters of left ventricu-lar structure in diastole and adiponectin level in the ChNPP ACUW of a «iodine» period with diagnosed T2DM, high-lighting its cardioprotective effect. At the same time, the content of FNP-α and IL-6 proinflammatory cytokines hada positive correlation with the main parameters of abnormal myocardial remodeling, indicating the possibility oftheir role in unfavorable cardiovascular modifications.

CONCLUSIONS

The decreased adiponectin level and elevated levels of TNF-α and IL-6 in the ChNPP ACUW of a«iodine» period having got the T2DM are the meaningful factors in progression of LV geometric remodeling. Togetherwith fibroplastic processes (a significant increase in ICVF) this may be a basis for the development of myocardialremodeling processes, namely a concentric hypertrophy, which is a prerequisite for the development of complica-tions in cardiovascular system.