P18 | NESTIN EXPRESSION IN THE MYOCARDIUM OF SPONTANEOUSLY HYPERTENSIVE RATS AND CONPLASTIC SHR-MTBN STRAIN, AND CO-EXPRESSION WITH CONNEXIN 43

D. Cizkova¹, J. M. Zurmanova², T. Artykov¹, F. Galatik², B. Elsnicova², J. Silhavy³, M. Pravenec³, J. Mokry¹ | ¹Department of Histology and Embryology, Faculty of Medicine in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic; ²Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic; ³Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic

A unique intermediate filament protein nestin is present in some stem, progenitor and developing cells and re-expressed in the adult tissues during processes recapitulating the developmental phases such as regeneration, e.g. of the skeletal muscle. In the myocardium nestin is shortly identified early prenatally in rodents and for as yet unexplained reasons it occurs in the adult diseased heart in humans as well. Previously we detected nestin in rare desmin+ cardiomyocytes, some vimentin+ interstitial cells and endothelia in the hypertrophic heart of the aging spontaneously hypertensive rats (SHR). In this work we immunohistochemically detected nestin in the hearts of the SHR-mtBN conplastic rat strain to reveal the impact of the mitochondrial genome of the normotensive BN rats on nestin expression in SHR myocardium. Then, we performed double immunofluorescence of nestin and connexin 43 to unveil any differences in the intercalated discs gap junction pattern between nestin+ and nestin- cardiomyocytes in the SHR myocardium. Nestin expression was only mildly more abundant in the SHR than in the SHR-mtBN 5-month-old rats. In the 15-month-old SHR rats, nestin was detected in higher number of cardiac cells evenly located in wall of the left ventricle and the interventricular septum, but in the SHR-mtBN rats of the same age this protein was expressed more in groups of cells in certain regions. The distribution of connexin 43 did not substantially differ between nestin+ and nestin- cardiomyocytes in the 5- and 15month-old SHR rats. In the aged hypertrophic myocardium gap junction arrangement was more irregular and connexin 43 expression was also situated at lateral plasmalemma. In conclusion, nestin occurrence in the heart of SHR rats depends on age and mitochondrial genome. Less frequent nestin re-expression reflects a lower intensity of cytoskeletal remodelling of myocardial cells more resistant to hypoxia in the SHR-mtBN rats. In the SHR cardiomyocytes nestin expression seems to be unrelated to impulse propagation by connexin 43. Nestin re-expression is apparently involved in structural remodelling in myocardial hypertrophy in SHR rats during aging.