Remodeling of rat cardiomyocytes after neonatal cryptosporidiosis. II. Deformation, excessive polyploidization, and HIF-1α overexpression

Epidemiological studies indicate that diseases of childhood increase the probability of the appearance in the remote future of pathologies of the cardiovascular system. Based on data indicating that the most common cause of poor health in children is infectious gastroenteritites, we studied the effect of cryptosporidiosis upon remodeling of cardiomyocytes and the heart in 18 age groups of rats in the first month of life. The disease induced by the widespread protozoan enteropathogen of human beings and animals Cryptosporidium parvum was manifested in growth retardation and moderate diarrhea. By methods of real-time polymerase chain reaction, cytophotometry, and image analysis, we established that cryptosporidiosis was associated with heart atrophy, as well as with a decrease of the total protein amount in cardiomyocytes and their thinning, excessive polyploidization, and hyperexpression of the hypoxia-induced factor (HIF-1α). Remodeling of cardiomyocytes and heart atrophy was revealed in all 18 age groups. However, the intensities of these changes differed, decreasing from the younger to the older groups. Excessive polyploidization and hyperexpression of HIF-1α were recorded predominantly in animals of 6- to 13-day age, whereas in the older animals they were weaker and statistically insignificant. The period of rat development from 6 to 13 days coincides with enhanced polyploidization of cardiomyocytes and with their transition from proliferative to the hypertrophic growth. Thus, our data have shown that cryptosporidial gastroenteritis can be a potential risk factor of cardiovascular diseases and that the period of polyploidization cardiomyocytes is one of the critical periods in the heart's postnatal development. © 2012 Pleiades Publishing, Ltd.