Altered calcium handling is an early sign of streptozotocin-induced diabetic cardiomyopathy.

@article{citeulike:1645727, abstract = {The main objective of the present study was to determine alterations of calcium handling in the diabetic rat heart during the transition from adaptive to maladaptive phase of cardiomyopathy. By inhibiting the nuclear enzyme poly(ADP-ribose) polymerase (PARP), we also investigated the possible role of this enzyme in the sequence of pathological events. Six weeks after induction of type I diabetes by injection of streptozotocin in rats, the hearts were perfused according to Langendorff. Intracellular-free calcium (Ca(2+)(i)) levels were measured by surface fluorometry using Indo-1 AM. Cyclic changes in Ca(2+)(i) concentrations and hemodynamic parameters were measured simultaneously. The hearts were challenged by infusion of isoproterenol. Six weeks of diabetes resulted in reduced inotropy and lusitropy. The diabetic hearts (DM) expressed a significantly elevated end-diastolic Ca(2+)(i) level (control, 111-/+20 vs DM, 221-/+35 nM). The maximal transport capacity of SERCA2a and conductance of RyR2 were reduced. These changes were not accompanied by major alterations in the tissue content of SERCA2a, RyR2, phospholamban and Na(+)/Ca(2+) exchanger. In response to beta-adrenergic activation, SERCA2a transport capacity and RyR2 conductance were stunted in the DM hearts. Inhibition of PARP induced minor changes in the mechanical function and calcium handling of the DM hearts. In conclusion, the observed changes in contractility and in Ca(2+)(i) handling are most likely attributable to functional disturbances of SERCA2a and RyR2 in this transitional phase of diabetes. At this stage of diabetes, PARP does not appear to play a significant pathogenetic role in the alterations in contractile function and calcium handling.}, address = {Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary.}, author = {Ligeti, L. and Szenczi, O. and Prestia, C. M. and Szab\'{o}, C. and Horv\'{a}th, K. and Marcsek, Z. L. and van Stiphout, R. G. and van Riel, N. A. and Op den Buijs, J. and Van der Vusse, G. J. and Ivanics, T. }, citeulike-article-id = {1645727}, issn = {1107-3756}, journal = {Int J Mol Med}, keywords = {calcium, diabetes, heart, isoproterenol, modeling, streptozotocin}, month = {June}, number = {6}, pages = {1035--1043}, posted-at = {2007-09-11 22:46:37}, priority = {0}, title = {Altered calcium handling is an early sign of streptozotocin-induced diabetic cardiomyopathy.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/16685413}, volume = {17}, year = {2006} }

TY - JOUR ID - citeulike:1645727 L3 - citeulike-article-id:1645727 TI - Altered calcium handling is an early sign of streptozotocin-induced diabetic cardiomyopathy. JF - Int J Mol Med VL - 17 IS - 6 SP - 1035 EP - 1043 AD - Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary. SN - 1107-3756 N2 - The main objective of the present study was to determine alterations of calcium handling in the diabetic rat heart during the transition from adaptive to maladaptive phase of cardiomyopathy. By inhibiting the nuclear enzyme poly(ADP-ribose) polymerase (PARP), we also investigated the possible role of this enzyme in the sequence of pathological events. Six weeks after induction of type I diabetes by injection of streptozotocin in rats, the hearts were perfused according to Langendorff. Intracellular-free calcium (Ca(2+)(i)) levels were measured by surface fluorometry using Indo-1 AM. Cyclic changes in Ca(2+)(i) concentrations and hemodynamic parameters were measured simultaneously. The hearts were challenged by infusion of isoproterenol. Six weeks of diabetes resulted in reduced inotropy and lusitropy. The diabetic hearts (DM) expressed a significantly elevated end-diastolic Ca(2+)(i) level (control, 111-/+20 vs DM, 221-/+35 nM). The maximal transport capacity of SERCA2a and conductance of RyR2 were reduced. These changes were not accompanied by major alterations in the tissue content of SERCA2a, RyR2, phospholamban and Na(+)/Ca(2+) exchanger. In response to beta-adrenergic activation, SERCA2a transport capacity and RyR2 conductance were stunted in the DM hearts. Inhibition of PARP induced minor changes in the mechanical function and calcium handling of the DM hearts. In conclusion, the observed changes in contractility and in Ca(2+)(i) handling are most likely attributable to functional disturbances of SERCA2a and RyR2 in this transitional phase of diabetes. At this stage of diabetes, PARP does not appear to play a significant pathogenetic role in the alterations in contractile function and calcium handling. KW - calcium KW - diabetes KW - heart KW - isoproterenol KW - modeling KW - streptozotocin AU - Ligeti, L AU - Szenczi, O AU - Prestia, CM AU - Szabó, C AU - Horváth, K AU - Marcsek, ZL AU - van Stiphout, RG AU - van Riel, NA AU - Op den Buijs, J AU - Van der Vusse, GJ AU - Ivanics, T PY - 2006/06// UR - http://view.ncbi.nlm.nih.gov/pubmed/16685413 ER -