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Fatty acid metabolism in isolated working hearts from spontaneously diabetic “BB”wistar rats
j Mol Cell Cardiol 19 (Supplement Ill) (1987)
160
CORRELATION BETWEEN IRON UPTAKE. LIPID PEROXIDATION AND ACTION POTENTIAL DURATION IN ~ULTURED HEART CELLS. G.Link 1"2, P. Ath~as 3, A. Grynberg 4, C. Hershko ~, A. Pinson I. ~Laboratory for Myocardial Research and ~Department of ~utrition, The Hebrew University-Hadassah Medical S c h o o l ~ Jerusalem, Israel. Jiaboratoire de Physiologie, 9 9 9 , France. 4 INRA, Dijon, 99 Faculte9 de Medecln, Dijon France. D Department of Internal Medicine, Shaare Zedek Medical Center. Cardiac iron (Ir) overload is a life-limiting complication in conditions requiring repeated transfusional therapy. Cultured heart c e l l s exposed for 24 h to 20 ~g/ml Ir, 39% uptake of Ir occurred with a concomitant i0- to 12-fold increase in MDA. Hypoxia (1% oxygen) increased Ir uptake by more than two-fold and was accompanied by only minor changes in c e l l u l a r MDA levels. Ascorbic acid and etocopherol led to a 73% decrease, and a 19% increase in Ir uptake, respectively. By contrast, c e l l u l a r MDA increased (from 2.339• to 4.352• nmol/mg), and was reduced (to 0.583• nmol/mg), in the presence of these two agents. Deferoxamine (DF) decreased both the c e l l u l a r Ir content, and MDA levels. Simultaneous treatment with DF and ascorbate or DF and e-tocopherol led to significant changes in MDA production patterns occurred. Ascorbic acid completely inhibited the beneficial effect of DF on MDA production in Ir-loaded cells, whereas ~-tocopherol potentiated the effects of DF. Ir-loading impaired membrane potential with significant reduction in overshoot and this effect was reversed by the addition of DF to the medium.
161
FATTY ACID METABOLISMIN ISQLATED WORKING HEARTS FROM SPONTANEOUSLY DIABETIC "BB" WISTAR RATS. G.D. Lopaschuk, H. Tsang. Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada. Myocardial fatty acid metabolism was studied in spontaneously-diabetic "BB" Wistar rats. The study involved 4 groups; control Wistar rats, non-diabetic littermates of "BB" Wistar rats, insulin-treated diabetic "BB" rats, and diabetic "BB" rats in which insulin treatment was removed 24 hours prior to study (uncontrolled diabetes). Hearts were perfused for 30 minutes as isolated working hearts in perfusate containing 1.2 mM (l-14C)-palmitate bound to 3% albumin, and Ii mM glucose. Palmitate oxidative rates were similar in all groups if the noted decrease in heart function of the diabetic animals was accounted for. In the uncontrolled diabetic rats an increased rate of palmitate incorporation into myocardial triglycerides was seen compared to treated diabetic, non-diabetic littermates, and control rats (8.5 + 0.3 umol/g dry/30 min. versus 4.8 + 0.3, 5.9 + 0.7 and 5.7 + 0.3 respectively). Myocardial levels of CoA were elevated in--the uncontr--olled diabeti~ rats compared to all other groups (647 _+ 25 nmol/g dry weight vs 484 ~ 27, 508 ~ 56, and 534 ~ 9, in treated diabetic, non-diabetic, and control rats respectively). Combined with earlier studies, the data suggest that high levels of myocardial coenzyme A contribute to the accumulation of myocardial triglyeerides seen in poorly controlled diabetes. Supported by the Juvenile Diabetes Foundation and Medical Research Council.
162
LECTINS AS CYTOCHEMICAL MARKERS OF MYOCARDIUM AND BLOOD VESSELS. N. L~the, Jutta Schaper, Max-Planck-Institute, Bad Nauheim, Federal Republic of Germany During the development of collaterals in the heart, cells of unknown origin appear in the vessel wall which do not precisely fit morphologically into one of the known cell types. Lectins have been used for cell typing on cryostat sections of swine (S) (experimental model of collateral growth) and human (H) myocardium. Cell type Lectins CONA DBA PNA RCAII UEAI WGA endothelium S + + + + + (capillaries) H + n.d. + + + endothelium S + + + + + (large vessels) H + n.d. + + + connective tissue S + + + H + n.d. + + myocytes S + + + H i + n.d. + + PNA and DBA selectively stained the endothelial cells of S-myocardium, UEAI reacted with H-myocardium. These results open the possibility to detect cells of endothelial origin in the vessel wall and to determine changes of the glycosylation pattern of cells during development of collaterals.
I
S.54
160
CORRELATION BETWEEN IRON UPTAKE. LIPID PEROXIDATION AND ACTION POTENTIAL DURATION IN ~ULTURED HEART CELLS. G.Link 1"2, P. Ath~as 3, A. Grynberg 4, C. Hershko ~, A. Pinson I. ~Laboratory for Myocardial Research and ~Department of ~utrition, The Hebrew University-Hadassah Medical S c h o o l ~ Jerusalem, Israel. Jiaboratoire de Physiologie, 9 9 9 , France. 4 INRA, Dijon, 99 Faculte9 de Medecln, Dijon France. D Department of Internal Medicine, Shaare Zedek Medical Center. Cardiac iron (Ir) overload is a life-limiting complication in conditions requiring repeated transfusional therapy. Cultured heart c e l l s exposed for 24 h to 20 ~g/ml Ir, 39% uptake of Ir occurred with a concomitant i0- to 12-fold increase in MDA. Hypoxia (1% oxygen) increased Ir uptake by more than two-fold and was accompanied by only minor changes in c e l l u l a r MDA levels. Ascorbic acid and etocopherol led to a 73% decrease, and a 19% increase in Ir uptake, respectively. By contrast, c e l l u l a r MDA increased (from 2.339• to 4.352• nmol/mg), and was reduced (to 0.583• nmol/mg), in the presence of these two agents. Deferoxamine (DF) decreased both the c e l l u l a r Ir content, and MDA levels. Simultaneous treatment with DF and ascorbate or DF and e-tocopherol led to significant changes in MDA production patterns occurred. Ascorbic acid completely inhibited the beneficial effect of DF on MDA production in Ir-loaded cells, whereas ~-tocopherol potentiated the effects of DF. Ir-loading impaired membrane potential with significant reduction in overshoot and this effect was reversed by the addition of DF to the medium.
161
FATTY ACID METABOLISMIN ISQLATED WORKING HEARTS FROM SPONTANEOUSLY DIABETIC "BB" WISTAR RATS. G.D. Lopaschuk, H. Tsang. Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada. Myocardial fatty acid metabolism was studied in spontaneously-diabetic "BB" Wistar rats. The study involved 4 groups; control Wistar rats, non-diabetic littermates of "BB" Wistar rats, insulin-treated diabetic "BB" rats, and diabetic "BB" rats in which insulin treatment was removed 24 hours prior to study (uncontrolled diabetes). Hearts were perfused for 30 minutes as isolated working hearts in perfusate containing 1.2 mM (l-14C)-palmitate bound to 3% albumin, and Ii mM glucose. Palmitate oxidative rates were similar in all groups if the noted decrease in heart function of the diabetic animals was accounted for. In the uncontrolled diabetic rats an increased rate of palmitate incorporation into myocardial triglycerides was seen compared to treated diabetic, non-diabetic littermates, and control rats (8.5 + 0.3 umol/g dry/30 min. versus 4.8 + 0.3, 5.9 + 0.7 and 5.7 + 0.3 respectively). Myocardial levels of CoA were elevated in--the uncontr--olled diabeti~ rats compared to all other groups (647 _+ 25 nmol/g dry weight vs 484 ~ 27, 508 ~ 56, and 534 ~ 9, in treated diabetic, non-diabetic, and control rats respectively). Combined with earlier studies, the data suggest that high levels of myocardial coenzyme A contribute to the accumulation of myocardial triglyeerides seen in poorly controlled diabetes. Supported by the Juvenile Diabetes Foundation and Medical Research Council.
162
LECTINS AS CYTOCHEMICAL MARKERS OF MYOCARDIUM AND BLOOD VESSELS. N. L~the, Jutta Schaper, Max-Planck-Institute, Bad Nauheim, Federal Republic of Germany During the development of collaterals in the heart, cells of unknown origin appear in the vessel wall which do not precisely fit morphologically into one of the known cell types. Lectins have been used for cell typing on cryostat sections of swine (S) (experimental model of collateral growth) and human (H) myocardium. Cell type Lectins CONA DBA PNA RCAII UEAI WGA endothelium S + + + + + (capillaries) H + n.d. + + + endothelium S + + + + + (large vessels) H + n.d. + + + connective tissue S + + + H + n.d. + + myocytes S + + + H i + n.d. + + PNA and DBA selectively stained the endothelial cells of S-myocardium, UEAI reacted with H-myocardium. These results open the possibility to detect cells of endothelial origin in the vessel wall and to determine changes of the glycosylation pattern of cells during development of collaterals.
I
S.54