scholarly journals Dynamics of myocardial adaptation to low-flow ischemia and hypoxemia

1996 ◽  
Vol 271 (6) ◽  
pp. H2300-H2305
Author(s):  
G. Merati ◽  
S. Allibardi ◽  
L. D. Monti ◽  
J. W. de Jong ◽  
M. Samaja
Keyword(s):  
Low Flow ◽  
Control Performance ◽  
Perfusion Medium ◽  
Atp Production ◽  
Lactate Release ◽  
Rat Hearts ◽  
O2 Supply ◽  
Developed Pressure ◽  
Myocardial Adaptation ◽  
Isolated Rat

We investigated whether one or more factors control performance in O2-limited hearts. For this purpose, we measured the dynamics of myocardial adaptation to reduced O2 supply with a specially designed setup, analyzing early changes after reduction in either flow of the perfusion medium or its PO2. For 10 min, 38 isolated rat hearts underwent low-flow ischemia or hypoxemia, matched for O2 supply. Early during ischemia, developed pressure declined at a rate of 311 +/- 25 mmHg/s; lactate release increased and then leveled off to 3.4 +/- 0.7 mumol/min within 2 min. During hypoxemia, pressure dropped initially, as observed during ischemia. However, it then increased before slowly decreasing. Lactate release during hypoxemia peaked at 13.0 +/- 2.3 mumol/min after 2 min, leveling off to 3.5 +/- 1.3 mumol/min. Glycogen decreased by 52 and 81% in ischemic and hypoxemic hearts, respectively (P < 0.05). Reexposure to ischemia or hypoxemia induced comparable changes in both groups. We conclude that, at the beginning of ischemia, a single factor does limit myocardial performance. This variable, which remains undisturbed for 10 min, is presumably O2 availability. In contrast, approximately 20 s after induction of hypoxemia, glycolytic ATP production can partially override low O2 availability by providing most of the energy needed. During repeated restriction of O2 supply, O2 availability alone limits performance during both ischemia and hypoxemia.

Independent dual perfusion of left and right coronary arteries in isolated rat hearts

1991 ◽  
Vol 261 (6) ◽  
pp. H2082-H2090 ◽  
Author(s):  
M. Avkiran ◽  
M. J. Curtis
Keyword(s):  
High Energy ◽  
Low Flow ◽  
Blue Dye ◽  
Ischemia And Reperfusion ◽  
Langendorff Preparation ◽  
Rat Hearts ◽  
Left And Right ◽  
Conventional Models ◽  
Aortic Cannula ◽  
Isolated Rat

A novel dual lumen aortic cannula was designed and constructed to permit independent perfusion of left and right coronary beds in isolated rat hearts without necessitating the cannulation of individual arteries. Stability of the dual-perfusion preparation was shown to be similar to that of the conventional Langendorff preparation, in terms of coronary flow, heart rate, and high-energy phosphate content. The independence of left and right perfusion beds was confirmed by unilateral infusion of disulfine blue dye and spectrophotometric detection of the dye in ventricular homogenates. Transient cessation of flow to the left coronary bed resulted in severe ventricular arrhythmias upon reperfusion, as in conventional models of regional ischemia and reperfusion. The dual-perfusion model is technically undemanding, reproducible, inexpensive, and can be used in several species. It enables studies with 1) regional low flow ischemia, 2) regional zero-flow ischemia without coronary ligation (with attendant damage to vasculature), 3) selective application of drugs or interventions to the ischemic-reperfused zone, and 4) selective application of components of ischemia and reperfusion to a site anatomically relevant to ischemic heart disease.

The Effects of Low-Flow Ischemia on K+Fluxes in Isolated Rat Hearts Assessed by87Rb NMR

1999 ◽  
Vol 31 (4) ◽  
pp. 817-826 ◽  
Author(s):  
V.V. Kupriyanov ◽  
B. Xiang ◽  
B. Kuzio ◽  
R. Deslauriers
Keyword(s):  
Low Flow ◽  
Rat Hearts ◽  
Isolated Rat

Abstract 1712: The P2Y 12 Antagonist Cangrelor and the GP IIb/IIIa Blocker Abciximab Reduce Platelet-Mediated Myocardial Injury After Ischemia and Reperfusion

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Jose A Barrabes ◽  
Javier Inserte ◽  
Maribel Mirabet ◽  
Adoracion Quiroga ◽  
Victor Hernando ◽  
...  
Keyword(s):  
Myocardial Injury ◽  
Myocardial Damage ◽  
Left Ventricular ◽  
Myocardial Salvage ◽  
Ischemia And Reperfusion ◽  
Activated Platelets ◽  
Rat Hearts ◽  
Developed Pressure ◽  
Enddiastolic Pressure ◽  
Isolated Rat

Objective: Platelets activated during experimental acute myocardial infarction (AMI) contribute to myocardial injury. We aimed to investigate whether platelets from patients with AMI increase myocardial damage after transient ischemia in isolated rat hearts and the modification of this effect by the P2Y 12 receptor antagonist cangrelor and the GPIIb/IIIa receptor blocker abciximab. Methods: Platelets were obtained from 9 AMI patients (7 thrombolyzed, all on aspirin) within 24 h after symptom onset. Incubation with 100 μM cangrelor or 50 μg/ml abciximab resulted, respectively, in 78 ± 4 and 90 ± 2% inhibition of aggregation (optical aggregometry). Isolated rat hearts (four simultaneous experiments per patient) were subjected to 40 min of global ischemia and 60 min of reperfusion. Hearts received no additional intervention (Control) or were infused during the 5 min prior to ischemia with platelets (22.5x10 6 /min), either untreated or treated with cangrelor or abciximab. Results: P-selectin expression (flow cytometry) in isolated platelets before infusion was 31 ± 3% (P = NS between groups). Platelets augmented myocardial injury, as demonstrated by worse left ventricular developed pressure (LVDevP), higher left ventricular enddiastolic pressure (LVEDP) and coronary resistance, and greater LDH release and infarct size (TTC staining), and both cangrelor and abciximab greatly attenuated these effects (Table ). Conclusions: Activated platelets from patients with AMI increase myocardial injury after ischemia and reperfusion, and cangrelor and abciximab attenuate this effect. The results support the notion that very early antiplatelet treatment may increase myocardial salvage by direct effects on the microcirculation in these patients.

Adenosine antagonism decreases metabolic but not functional recovery from ischemia

1991 ◽  
Vol 260 (1) ◽  
pp. H193-H200 ◽  
Author(s):  
D. A. Angello ◽  
J. P. Headrick ◽  
N. M. Coddington ◽  
R. M. Berne
Keyword(s):  
Functional Recovery ◽  
Left Ventricular ◽  
Low Flow ◽  
Ischemia And Reperfusion ◽  
Constant Flow ◽  
Hemodynamic Parameters ◽  
Isolated Hearts ◽  
Rat Hearts ◽  
Adenosine Antagonism ◽  
Developed Pressure

The effect of adenosine receptor antagonism on function and metabolism was examined in isolated hearts during low flow ischemia and reperfusion. Isovolumic rat hearts perfused at constant flow were subjected to 30 min of ischemia followed by 30 min of reperfusion. Infusion of vehicle or 10 microM 8-phenyltheophylline (8-PT) was initiated 10 min before ischemia and maintained throughout reperfusion. 8-PT infusion had no significant effects on hemodynamic parameters or metabolism preischemia. During ischemia, left ventricular developed pressure declined to approximately 15% of preischemic values in control and 8-PT hearts, and ATP and PCr decreased to approximately 73 and 60% of preischemic values. Inorganic phosphate (Pi) increased to 353 = 41 and 424 +/- 53% of preischemic values in control and 8-PT hearts, respectively. After reperfusion, function recovered to greater than 95% of preischemic levels in control and 8-PT hearts. Unlike control hearts, recovery of metabolites was significantly different during reperfusion in 8-PT hearts (P less than 0.05); ATP, phosphocreatine, and Pi recovered to 82 +/- 8, 71 +/- 8, and 281 +/- 27% of preischemic values, respectively. Venous purine washout was significantly greater (P less than 0.05) during reperfusion in 8-PT hearts (327 +/- 113 nmol) than in control hearts (127 +/- 28 nmol). Blockade of adenosine receptors appears to adversely affect metabolic but not functional recovery in the ischemic-reperfused myocardium.

Metabolic fate of glucose in reversible low-flow ischemia of the isolated working rat heart

1996 ◽  
Vol 270 (3) ◽  
pp. H817-H826 ◽  
Author(s):  
H. Bolukoglu ◽  
G. W. Goodwin ◽  
P. H. Guthrie ◽  
S. G. Carmical ◽  
T. M. Chen ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Glucose Oxidation ◽  
Glycogen Synthesis ◽  
Coronary Perfusion Pressure ◽  
Low Flow ◽  
Coronary Perfusion ◽  
Myocardial Glucose Metabolism ◽  
Lactate Release ◽  
Exogenous Substrate ◽  
Rat Hearts

The acute adaptation of myocardial glucose metabolism in response to low-flow ischemia and reperfusion was investigated in isolated working rat hearts perfused with bicarbonate saline containing glucose (10 mM) and insulin (40 microU/ml). Reversible low-flow ischemia was induced by reducing coronary perfusion pressure from 100 to 35 cmH2O. Tritiated glucose was used to assess rates of glucose transport and phosphorylation, flux from glucose to pyruvate, and oxidation of exogenous glucose. Rates of glycogen synthesis and glycolysis were also assessed. With ischemia, cardiac power decreased by more than two-thirds. Rates of glucose uptake and flux from glucose to pyruvate remained unchanged, while glucose oxidation declined by 61%. Rates of lactate release more than doubled, and fractional enrichment of glycogen remained the same. During reperfusion, glucose oxidation returned to the preischemic values. When isoproterenol was added during ischemia, glucose uptake increased, glycogen decreased, and lactate release increased. No effect was seen with pacing. We conclude that during low-flow ischemia and with glucose as the only exogenous substrate, net glucose uptake remains unchanged. There is a reversible redirection between glycolysis and glucose oxidation, while glycogen synthesis continues during ischemia and is enhanced with reperfusion.

Effect of Salidroside on Cardiac Functional Recovery

2013 ◽  
Vol 798-799 ◽  
pp. 1030-1032
Author(s):  
Yan Zhang ◽  
Zhong Hua Zheng ◽  
Yue Peng Wang ◽  
Guo Liang Peng ◽  
Liu Hang Wang
Keyword(s):  
Flow Rate ◽  
Functional Recovery ◽  
Rat Heart ◽  
Coronary Flow ◽  
Left Ventricular ◽  
Cardioprotective Effect ◽  
Decrease Rate ◽  
Rat Hearts ◽  
Developed Pressure ◽  
Isolated Rat

To investigate the cardioprotective effect of salidroside to rat heart subjected to 8-hour hypothermic storage and 2-hour normothermic reperfusion. Isolated rat hearts were perfused with Langendorff model; after 30 minutes of baseline, the hearts were arrested and stored by St. Thomas solution (STS) without (STS group) or with different concentration salidroside at 4 °C for 8 hours, then reperfused for 2 hours. Compared with STS group, both middle and high dosage in STS greatly improved the recovery of left ventricular developed pressure (LVDP), maximum LVDP increase and decrease rate (±dp/dt), coronary flow rate (CF). Our study demonstrated that the salidroside was beneficial to improving cardiac functional recovery.

NMR measurements of Na+ and cellular energy in ischemic rat heart: role of Na(+)-H+ exchange

1993 ◽  
Vol 265 (6) ◽  
pp. H2017-H2026 ◽  
Author(s):  
M. M. Pike ◽  
C. S. Luo ◽  
M. D. Clark ◽  
K. A. Kirk ◽  
M. Kitakaze ◽  
...  
Keyword(s):  
Ph Regulation ◽  
Left Ventricular ◽  
Atp Depletion ◽  
Low Flow ◽  
Cellular Energy ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Ischemic Period ◽  
Developed Pressure ◽  
Zero Flow

Interleaved 23Na- and 31P-nuclear magnetic resonance (NMR) spectra were continuously collected on perfused rat hearts subjected to low-flow ischemia (30 min, 10% flow) or zero-flow ischemia (21 min) followed by reperfusion. During untreated low-flow and zero-flow ischemia, intracellular Na+ (Nai+) increased by 53 +/- 11 (+/- SE) and 78 +/- 8%, respectively, and remained elevated for zero-flow hearts. However, during both low- and zero-flow ischemia, Nai+ did not increase in hearts treated with the Na(+)-H+ exchange inhibitor, 5-(N-ethyl-N-isopropyl)amiloride (EIPA). The pH decreases during ischemia were unchanged. EIPA treatment reduced ATP depletion during ischemia. During reperfusion from zero-flow ischemia, EIPA-treated hearts displayed more rapid and extensive recoveries of phosphocreatine and ATP. Recovery of left ventricular developed pressure was improved for zero-flow hearts treated with EIPA during the ischemic period exclusively (104 +/- 13%) compared with untreated hearts (36 +/- 21%). These data indicate that Na(+)-H+ exchange is an important mechanism for Nai+ accumulation, but not for pH regulation, during myocardial ischemia. Additionally, Nai+ homeostasis plays an important role in the postischemic recovery of cellular energy and ventricular function.

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