RAT CARDIOMYOCYE REMODELING AFTER NEONATAL CRYPTOSPORIDOSIS. II. ELONGATION, EXCESSIVE POLYPLODIZATION AND
HIF-lα OVEREXPRESSION
Anatskaya O.V.,* Sidorenko N.V., Matveev I.V., Kropotov A.V., Vinogradov A.E.
Institute of Cytology RAS, St Petersburg;
* e-mail: anatskaya@mail.cytspb.rssi.ru
Retrospective epidemyological studies evidence that infant diseases leave survivors with an increased susceptibility to cardiovascular diseases in later life. At the same time,
the mechanisms of this link remain poorly understood. Based on medical statistics reporting that infectious gastroenteritis is the most common cause of maladies in babies, infants
and children, we analysed the effects of moderate cryptosporidial gastroenteritis on the heart and ventricular cardiomyocyte remodelling in rats of the first month of life. The disease
was challenged by a worldwide human protozoic pathogen Cryptosporidium parvum (Apicomplexa, Sporozoa). The main symptoms manifested in the growth retardation moderate
diarrhea. Using real-time PCR, cytophotometry, confocal microscopy and image analysis, we indicated that cryptosporidiosis was associated, with the atrophy heart and the elongation,
narrowing, protein content decrease and hyperpolyploidization of cardiomyocytes and the moderate overexpression of hypoxia inducible factor 1a (HIF-lα) mRNA.
Cardiomyocyte shape remodeling and heart atrophy presented in all age groups. The severity of these changes, hovewer, declined gradually from younger to older groups. In contrast,
hyperpolyploidization and HIF-lα mRNA overexpression were registered mainly among animals aged between 6 and 13 days, and were barely detected and non-significant
in older age groups. In the rat the time period covering 6-13 days after birth is known to coincide with the intensive cardiomyocyte polyploidization and the switch from proliferation to
hypertrophy. Thus, our data indicate that neonatal cryptosporidiosis may be potential cardiovascular diseases risk factor and that one of the critical time windows for the growing heart
covers the time period when cardiomyocyte undergo polyploidization.
Key words: HIF-lα, neonatal cardiomyocytes, polyploidy, atrophy, elongation, cryptosporidial gastroenteritis, criticlal period in heart formation
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