Oxidized LDL (OxLDL), a causal factor in atherosclerosis, induces the expression of heat shock proteins (Hsp) in a variety of cells. In this study, we investigated the role of CD36, an OxLDL receptor, and peroxisome proliferator-activated receptor gamma (PPAR gamma) in OxLDL-induced Hsp70 expression. Overexpression of dominant-negative forms of CD36 or knockdown of CD36 by siRNA transfection increased OxLDL-induced Hsp70 protein expression in human monocytic U937 cells, suggesting that CD36 signaling inhibits Hsp70 expression. Similar results were obtained by the inhibition of PPAR gamma activity or knockdown of PPAR gamma expression. In contrast, overexpression of CD36, which is induced by treatment of MCF-7 cells with troglitazone, decreased Hsp70 protein expression induced by OxLDL. Interestingly, activation of PPAR gamma through a synthetic ligand, ciglitazone or troglitazone, decreased the expression levels of Hsp70 protein in OxLDL-treated U937 cells. However, major changes in Hsp70 mRNA levels were not observed. Cycloheximide studies demonstrate that troglitazone attenuates Hsp70 translation but not Hsp70 protein stability. PPAR gamma siRNA transfection reversed the inhibitory effects of troglitazone on Hsp70 translation. These results suggest that CD36 signaling may inhibit stress- induced gene expression by suppressing translation via activation of PPAR gamma in monocytes. These findings reveal a new molecular basis for the anti-inflammatory effects of PPAR gamma.
Antigens, CD36/*physiology ; Cell Line, Tumor ; Chromans/pharmacology ; Cycloheximide/pharmacology ; HSP70 Heat-Shock Proteins/*biosynthesis ; Humans ; Lipoproteins, LDL/pharmacology/*physiology ; Monocytes/drug effects/metabolism ; PPAR gamma/agonists/antagonists & inhibitors/*physiology ; Protein Synthesis Inhibitors/pharmacology ; Signal Transduction ; Thiazolidinediones/pharmacology

To assess the regional difference and influence of the biological variables on atherosclerosis in female, we analyzed 7 segments of aorta (2 ascending, 3 thoracic, and 2 abdominal) from 90 superficially healthy Korean women (39+/-14 yr of age) who died from external causes. Tissue specimens were macroscopically examined and histopathologically divided into 7 grades for scoring (ATHERO, from 0=intact, to 6=thrombi formation). Lumen diameter (LD), wall thickness (WT), intima thickness (INT), and media thickness (MED) were obtained by computed morphometry. Atherosclerosis was common in the distal infrarenal (C2), proximal thoracic (B1), and proximal ascending (A1) segments. Total 95.6% of all subjects had atherosclerosis of variable degree in one or more segments, but an aneurysmal change was not found. The number of atherosclerotic segments and atherosclerosis score in the 7 segments increased with aging. However, the body size did not affect the aortic size and ATHERO. With aging, LD and INT of the A1, B1 and C2 increased (p<.00001); WT of the B1 and C2 increased (p<.01); and MED of C2 decreased (p<.01). LD and WT of the B1 and C2 (p<.05), INT of the A1, B1 and C2 (p<.00001) increased, and MED of C2 decreased (p<.01) with ATHERO. These data suggest that age is simple but a reliable parameter for estimating the progression of atherosclerosis.
Adolescent ; Adult ; Age Factors ; Aged ; Aged, 80 and over ; Aorta/*anatomy & histology/pathology ; Aortic Diseases/*diagnosis/*pathology ; Atherosclerosis/*diagnosis/*pathology ; Autopsy ; Cadaver ; Disease Progression ; Female ; Humans ; Korea ; Middle Aged

Recent studies demonstrated that brief period of Ca2+ depletion and repletion (Ca2+ preconditioning, CPC) has strong protective effects against ischemia in a rat heart. CPC and classic preconditioning (IPC) were compared in relation with infarct size and protein kinase C (PKC) isozymes. Isolated Langendorff-perfused rabbit hearts were subjected to 45-min ischemia (Isc) followed by 120-min reperfusion (R) with or without IPC, induced by 5-min Isc and 10-min R. In the CPC hearts, 5-min Ca2+ depletion and 10-min repletion (CPC) were given before 45-min Isc, with or without concurrent PKC inhibition (calphostin C, 200 nmol/L). IPC enhanced recovery of LV function, while CPC did not. Infarct size was significantly reduced by both CPC and IPC (p < 0.05 vs. ischemic control). Membrane PKC was significantly increased from 2.53 +/- 0.07 (baseline, nmol/g tissue) to 3.11+/-0.07, 3.34 +/- 0.11, 3.15 +/- 0.09, and 3.06 +/- 0.08 by IPC, IPC and 45-min Isc, CPC and 45-min Isc, respectively (p < 0.01). Immunoblots of membrane PKC were increased by IPC, IPC and 45-min Isc, and CPC. These effects were abolished by PKC inhibition. Thus, activation of PKC may have trigger role in the mechanism of cardioprotective effect by CPC.
Animals ; Calcium/*pharmacology ; Cardiotonic Agents/*pharmacology ; In Vitro ; *Ischemic Preconditioning, Myocardial ; Isoenzymes/metabolism ; L-Lactate Dehydrogenase/metabolism ; Male ; Myocardial Infarction/*pathology ; Myocardium/enzymology/pathology ; Protein Kinase C/metabolism ; Rabbits

BACKGROUND AND OBJECTIVES: Recent reports suggest that brief periods of low-flow ischemia (lf Isc) and reperfusion (R) before prolonged Isc mimic ischemic preconditioning (IPC) in murine hearts, probably by a preservation of high energy phosphates. MATERIALS AND METHODS: In order to test this hypothesis, Langendorff-perfused isolated rabbit hearts were subjected to 45 min lf Isc (5% of baseline perfusion flow) with lf IPC or not, followed by 120 min R. lf IPC was induced by a single episode of 5 min lf Isc and 10 min R. These were compared with IPC hearts by 5 min no-flow Isc and 10 min R. RESULTS: lf IPC as well as IPC enhanced post-ischemic functional recovery although IPC did not reduce infarct size (Isc control, 37.5+/-3.1, IPC, 16.2+/-1.5, lf Isc, 43.0+/-0.7, and lf IPC, 40.4+/-1.0% of the left ventricle). Myocardial ATP hydrolysis and lactate production during the preischemic, ischemic, and reperfusion periods were not differ between the experimental groups. CONCLUSION: These results suggest that a brief period of lf Isc could not precondition the rabbit heart and the energy metabolism hypothesis may not be a universal mechanism for the cardioprotective effect of IPC.
Adenosine Triphosphate ; Energy Metabolism ; Heart ; Hydrolysis ; Ischemia ; Ischemic Preconditioning ; Lactic Acid ; Myocardial Infarction ; Perfusion* ; Phosphates ; Reperfusion

BACKGROUND AND OBJECTIVES: We investigated the ability of a brief heat shock on day one to provide delayed protection against lethal heat stress on day two in a rat-derived H9c2 cardiomyoblast cell line with reference to the role of heat shock protein 25/27, 70i and the p38MAPK signalling pathway. MATERIALS, METHODS AND RESULTS: Heat preconditioning(Heat P; 20min at 42+/-0.1degrees C) and adenosine(ADO) administered on day 1 protected against cell death under lethal heat challenge (75min at 42+/-0.1degrees C) on day 2 as measured by MTT test: ( % cell viability: Heat P: 79.9+/-3.23%, ADO: 71.9+/-4.10% vs. control: 52.7+/-1.65% respectively ). This protection was abolished by treatment with SB203580 or cytochalasine D prior to the protective stimulus on day 1( SB203580: 64.1+/-4.37%, cytochalasine D: 73.1+/-4.33% vs. Heat P ). Western blotting analysis indicated a significant accumulation of hsp70i in Heat P and SB203580-treated Heat P cells compared to control and adenosine-, SB203580-treated cells. Phosphorylation of hsp25 was significantly increased in Heat P cells compared to control cells. We also observed fragmentation of F-actin and formation of F-actin aggregates in cells exposed to lethal heat challenge. In contrast, the delayed cytoprotection preserved the F-actin bundles under lethal heat challenge. Hsp27-overexpressed, stable clones were more resistant to lethal heat shock when compared to control cells transfected with the vector alone. CONCLUSION: These data suggest an important role for p38MAPK/hsp25/27 pathway as a potential distal effector of heat-induced delayed protection.
Actins ; Blotting, Western ; Cell Death ; Cell Line ; Cell Survival ; Clone Cells ; Cytoprotection ; Cytoskeleton* ; Heat-Shock Proteins* ; Hot Temperature* ; Phosphorylation ; Shock

BACKGROUND: Recent studies suggest that the cardioprotective effect of ischemic preconditioning (IPC) is related to intracellular glycogen content in rat hearts, however, controversies still remain. METHODS: To test this hypothesis, isolated Langendorff-perfused rabbit hearts were subjected to 45 min global ischemia followed by 120 min reperfusion with IPC (n=0) or without IPC (ischemic control, n=). IPC was induced by one cycle of 5 min global ischemia and 10 min reperfusion. In the glucose (G)-free preconditioned group (n=0), G depletion-repletion was induced by perfusion with G-free Tyrode solution for 5 min and then G-containing Tyrode solution for 10 min followed by 45 min ischemia and 120 min reperfusion. For glycogen depletion or loading, hearts were treated with sodium acetate (NA, 5 mM, n=) or insulin (Ins, 1 unit/L, n=) for 15 min before 45 min ischemia. Left ventricular function and coronary flow (CF) were continuously recorded during experiments. Myocardial cytosolic and membrane protein kinase C (PKC) activities were measured by 32P-gamma-ATP incorporation into PKC-specific pepetide; glycogen content in the cardiac myocytes was determined by spectrophotometry with amyloglucosidase; expression of PKC isozymes was determined by Western blot with monoclonal antibodies. Infarct size was determined by staining with tetrazolium salt and planimetry. Data were analyzed by ANOVA and Tukey's post-hoc test. RESULTS: IPC or G-free preconditioning enhanced LV functional recovery; NA did not influence on functional recovery but Ins depressed it. Infarct size was significantly reduced by IPC, G-free preconditioning, and NA treatment (35.3+/-2.1% in the ischemic control, 18.7+/-1.2% in the IPC, 22.1+/-1.2% in the G-free preconditioned, 16.3+/-1.2% in the NA-treated group, and 32.8+/-1.6% in the Ins-treated group, p<0.05). Membrane PKC activities significantly increased by IPC, IPC and 45 min ischemia, G-free preconditioning, and G-free preconditioning and 45 min ischemia; especially, expression of membrane PKC-epsilon increased by IPC and G-free preconditioning. Glycogen content decreased by 45 min ischemia, IPC, G-free preconditioning, and by NA treatment, but increased by Ins treatment. CONCLUSION: These results suggest that in rabbit heart, intracellular glycogen may not significantly be related with the cardioprotective effect of IPC; G-free preconditioning could not improve post-ischemic contractile dysfunction but it has an infarct size-limiting effect; this cardioprotective effect may be related in part to activation of PKC, especially epsilon isozyme.
Animals ; Antibodies, Monoclonal ; Blotting, Western ; Cytosol ; Glucan 1,4-alpha-Glucosidase ; Glucose ; Glycogen* ; Heart ; Insulin ; Ischemia ; Ischemic Preconditioning* ; Isoenzymes ; Membrane Proteins ; Membranes ; Myocytes, Cardiac ; Perfusion ; Phosphotransferases ; Protein Kinase C* ; Protein Kinases* ; Rats ; Reperfusion ; Sodium Acetate ; Spectrophotometry ; Ventricular Function, Left

We provided a curve-fit equation to predict the normal heart weight (g) in Koreans by examining 422 autopsies (215 males and 207 females, from newborn to age 77 yr) who were relatively in good general condition. Heart weight was well correlated with body surface area (m2), body weight (kg), and body height (cm) but poorly with age in both sex. Heart weight progressively increased from birth to the earlier 3rd and 4th decades in male and female, respectively, and then gradually decreased; mean heart weight of all age group was greater in male than in female and significantly different from birth to 4th decade. In both sex, heart weight exponentially increased in accordance with the increase of body height, body weight, and body surface (in male, heart weight=0.00312 x body height(2.239), r2=0.750, p<0.0001; in female, heart weight=0.00443 x body height(2170), r2=0.781, p<0.0001; in male, heart weight=9.22 x body weight(0.853), r2=0.770, p<0.0001; in female, heart weight=9.00 x body weight0.855, r2=0.820, p<0.0001; in male, heart weight=155.18 x body surface area1.290, r=0.808, p<0.0001; in female, heart weight=124.13 x body surface area1.242, r=0.834, p<0.0001). These results indicate that heart weight is better correlated with body surface area than with body weight; however, body weight should be a better determinant of a predicted heart weight, since body surface area is entirely dependent on body height and body weight.
Adolescence ; Adult ; Age Factors ; Aged ; Body Height ; Body Weight ; Child ; Child, Preschool ; Female ; Heart/anatomy & histology* ; Human ; Infant ; Infant, Newborn ; Korea ; Male ; Middle Age ; Organ Weight

BACKGROUND: Recent studies have suggested that the cardioprotective effect of ischemic preconditioning (IP) is closely related to glycogen depletion and attenuation of intracellular acidosis. In the present study, the authors tested this hypothesis by perfusion isolated rabbit hearts with glucose(G) is closely related to glycogen depletion and attenuation of intracellular acidosis. In the present study, the authors tested this hypothesis by perfusion isolated rabbit hearts with glucose(G)-free perfusate. MATERIAL AND METHOD: Hearts isolated from New Zealand white rabbits (1.5~2.0 kg body weight) were perfused with Tyrode solution by Langendorff technique. After stabilization of baseline hemodynamics, the hearts were subjected to 45 min global ischemia followed by 120 min reperfusion with IP(IP group, n=13) or without IP(ischemic control group, n=10). IP was induced by single episode of 5 min global ischemia and 10 min reperfusion. In the G-free preconditioned group(n=12), G depletion was induced by perfusionwith G-free Tyrode solution for 5 min and then perfused with G-containing Tyrode solution for 10 min; and 45 min ischemia and 120 min reperfusion. Left ventricular functionincluding developed pressure(LVDP), dP/dt, heart rate, left ventricular end-distolic pressure (LVEDP) and coronary flow (CF) were measured. Myocardial cytosolic and membrane PKC activities were measured by 32P-gamma-ATP incorporation into PKC-specific peptide and PKC isozymes were analyzed by Western blot with monoclonal antibodies. Infarct size was determined by staining with TTC (tetrazolium salt) and planimetry. Data were analyzed by one-way analysis of variance (ANOVA) and Turkey's post-hoc test. RESULT: In comparison with the ischemic control group, IP significantly enhanced functional recovery of the left ventricle; in contrast, functional significantly enhanced functional recovery of the left ventricle; in contrast, functional recovery were not significantly different between the G-free preconditioned and the ischemic control groups. However, the infarct size was significantly reduced by IP or G-free preconditioning (39+/-2.7% in the ischemic control, 19+/-1.2% in the IP, and 15+/-3.9% in the G-free preconditioned, p<0.05). Membrane PKC activities were increased significantly after IP (119%), IP and 45 min ischemia(145%), G-free [recpmdotopmomg (150%), and G-free preconditioning and 45 min ischemia(127%); expression of membrane PKC isozymes, alpha and beta, tended to be increased after IP or G-free preconditioning. CONCLUSION: These results suggest that in isolated Langendorff-perfused rabbit heart model, G-free preconditioning (induced by single episode of 5 min G depletion and 10 min repletion) colud not improve post-ischemic contractile dysfunction(after 45-minute global ischemia); however, it has an infarct size-limiting effect.
Acidosis ; Antibodies, Monoclonal ; Blotting, Western ; Cytosol ; Glucose ; Glycogen* ; Heart ; Heart Rate ; Heart Ventricles ; Hemodynamics ; Ischemia ; Ischemic Preconditioning* ; Isoenzymes ; Membranes ; Perfusion ; Rabbits ; Reperfusion

This study was designed to provide a evidence that adenosine-mediated activation of protein kinase C and K(ATP) channel was a important step on the cardioprotection mechanism of ischemic preconditioning (IP). Isolated Langendorff-perfused New Zealand White rabbit hearts were subjected to 45 min of global ischemia (I) and 120 min reperfusion (R) with or without IP. IP was induced by a single dose of 5 min I and 10 min R. Part of the IP hearts was treated with non-specific adenosine receptor blocker 8-sulfophenyltheophylline (SPT; 100 micromol) and K(ATP) channel blocker glibenclamide (10 micromol) 5min before IP, respectively. To determine the effect of IP, we measured the left ventricular function, infarct size, adenosine concentration in the coronary flow and total protein kinase C activity. PKC activity was determined by (32)P-gamma-ATP incorporation into PKC specific peptide. IP enhanced improvement of functional recovery and caused a decrease in the infarct size from 19.9+/-0.05% in the ischemic-control group to 5.5+/-1.39% in the IP group (p<0.05). In the SPT- and glibenclamid-treated hearts, however, these anti-ischemic effect was disappeared. Adenosine release from the cardiac tissue was abruptly increased to 10~20 folds baseline just after IP. Cytosolic PKC activity decreased significantly in the IP hearts, while in the membrane fraction, activity was increased (45 min I, p<0.05; 120 min R, p<0.01). In the SPT-treated hearts, IP did not make those activity changes of PKC. These data suggest that adenosine induced the anti-ischemic effect via PKC activation. And it also show that K(ATP) channel may work on the protection as a final effector.
Adenosine* ; Cytosol ; Glyburide ; Heart* ; Ischemia ; Ischemic Preconditioning* ; Membranes ; New Zealand ; Protein Kinase C ; Receptors, Purinergic P1 ; Reperfusion ; Ventricular Function, Left

BACKGROUND: We tested recent evidences that IP triggers selective activation of protein kinase C (PKC) isozymes using isolated Langendorff-perfused rabbit heart with PKC activator, phorbol ester (PMA, 0.01 nM) or inhibitor (calphostin C, 200 nM). METHODS: After stabilization of baseline hemodynamics, the hearts were subjected to 45 min global ischemia (I) followed by 120 min reperfusion (R) with IP (IP group, n=18) or without IP (ischemic control group, n=16). IP was induced by single episode of 5 min I and 10 min R. In the PMA-treated group (n=19) and calphostin C-treated preconditioned group (n=15), PMA and calphostin C was given for 5 and 15 min before 45 min I, respectively. Myocardial cytosolic and membrane PKC activities were measured by 32P- -ATP incorporation into PKC-specific pepetide: PKC isozymes were analyzed by Western blot with monoclonal antibodies. RESULTS: IP significantly increased the recovery of the LV function including LVDP and coronary flow (p <0.05):however, enhancement of the functional recovery disappeared by calphostin C or PMA treatment. Cytosolic PKC activity decreased to 82-76% in the IP and PMA-treated group (p <0.05): membrane PKC activity increased to 218-272% (p <0.01). However, both fraction of PKC activity was not changed in the calphostin C-treated preconditioned group. In addition, Western blot revealed that PKC- alpha and epsilon, especially epsilon, were selectively translocated during subsequent sustained ischemia after IP or PMA administration. IP and PMA also reduced infarct size (frim 38 to 10-20%, p <0.05). However, calphostin C blocked infarct reduction effect of IP. CONCLUSION: These results indicate that in isolated rabbit heart model, cardioprotective effect of IP may be related, at least in part, to trigger selective translocation of PKC, especially epsilon isotype.
Antibodies, Monoclonal ; Blotting, Western ; Cytosol ; Heart ; Hemodynamics ; Ischemia ; Ischemic Preconditioning* ; Isoenzymes ; Membranes ; Protein Kinase C* ; Protein Kinases* ; Reperfusion