RESUMEN

The role of opioid kappa1 and kappa2 receptors in reperfusion cardiac injury was studied. Male Wistar rats were subjected to a 45-min coronary artery occlusion followed by a 120-min reperfusion. Opioid kappa receptor agonists were administered intravenously 5 min before the onset of reperfusion, while opioid receptor antagonists were given 10 min before reperfusion. The average value of the infarct size/area at risk (IS/AAR) ratio was 43 - 48% in untreated rats. Administration of the opioid kappa1 receptor agonist (-)-U-50,488 (1 mg/kg) limited the IS/AAR ratio by 42%. Administration of the opioid kappa receptor agonist ICI 199,441 (0.1 mg/kg) limited the IS/AAR ratio by 41%. The non-selective opioid kappa receptor agonist (+)-U-50,488 (1 mg/kg) with low affinity for opioid kappa receptor, the peripherally acting opioid kappa2 receptor agonist ICI 204,448 (4 mg/kg) and the selective opioid ?2 receptor agonist GR89696 (0.1 mg/kg) had no effect on the IS/AAR ratio. Pretreatment with naltrexone, the peripherally acting opioid receptor antagonist naloxone methiodide, or the selective opioid kappa2 receptor antagonist nor-binaltorphimine completely abolished the infarct-reducing effect of (-)-U-50,488 and ICI 199,441. Pretreatment with the selective opioid ? receptor antagonist TIPP[psi] and the selective opioid µ receptor antagonist CTAP did not alter the infarct reducing effect of (-)-U-50,488 and ICI 199,441. Our study is the first to demonstrate the following: (a) the activation of opioid kappa2 receptor has no effect on cardiac tolerance to reperfusion; (b) peripheral opioid kappa1 receptor stimulation prevents reperfusion cardiac injury; (c) ICI 199,441 administration resulted in an infarct-reducing effect at reperfusion; (e) bradycardia induced by opioid kappa receptor antagonists is not dependent on the occupancy of opioid kappa receptor.

Asunto(s)

3,4-Dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclohexil)-bencenacetamida, (trans)-Isómero/administración & dosificación , Analgésicos Opioides/administración & dosificación , Infarto del Miocardio/prevención & control , Daño por Reperfusión Miocárdica/prevención & control , Miocitos Cardíacos/efectos de los fármacos , Pirrolidinas/administración & dosificación , Receptores Opioides kappa/agonistas , 3,4-Dicloro-N-metil-N-(2-(1-pirrolidinil)-ciclohexil)-bencenacetamida, (trans)-Isómero/toxicidad , Administración Intravenosa , Analgésicos Opioides/toxicidad , Animales , Arritmias Cardíacas/inducido químicamente , Arritmias Cardíacas/fisiopatología , Modelos Animales de Enfermedad , Frecuencia Cardíaca/efectos de los fármacos , Masculino , Infarto del Miocardio/metabolismo , Infarto del Miocardio/patología , Daño por Reperfusión Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/patología , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Antagonistas de Narcóticos/administración & dosificación , Piperazinas/administración & dosificación , Pirrolidinas/toxicidad , Ratas Wistar , Receptores Opioides kappa/metabolismo , Transducción de Señal

RESUMEN

Chronic continuous normobaric hypoxia (CNH) increases cardiac tolerance to ischemia/reperfusion injury in vivo and this effect is mediated via µ and delta2 opioid receptors (ORs) activation. CNH has also been shown to be cardioprotective in isolated rat heart. In this study, we hypothesize that this cardioprotective effect of CNH is mediated by activation of µ and delta2 ORs and preservation of mitochondrial function. Hearts from rats adapted to CNH (12 % oxygen) for 3 weeks were extracted, perfused in the Langendorff mode and subjected to 45 min of global ischemia and 30 min of reperfusion. Intervention groups were pretreated for 10 min with antagonists for different OR types: naloxone (300 nmol/l), the selective delta OR antagonist TIPP(psi) (30 nmol/l), the selective delta1 OR antagonist BNTX (1 nmol/l), the selective delta2 OR antagonist naltriben (1 nmol/l), the selective peptide µ OR antagonist CTAP (100 nmol/l) and the selective delta OR antagonist nor-binaltorphimine (3 nmol/l). Creatine kinase activity in coronary effluent and cardiac contractile function were monitored to assess cardiac injury and functional impairment. Additionally, cardiac tissue was collected to measure ATP and to isolate mitochondria to measure respiration rate and calcium retention capacity. Adaptation to CNH decreased myocardial creatine kinase release during reperfusion and improved the postischemic recovery of contractile function. Additionally, CNH improved mitochondrial state 3 and uncoupled respiration rates, ADP/O, mitochondrial transmembrane potential and calcium retention capacity and myocardial ATP level during reperfusion compared to the normoxic group. These protective effects were completely abolished by naloxone, TIPP(psi), naltriben, CTAP but not BNTX or nor-binaltorphimine. These results suggest that cardioprotection associated with adaptation to CNH is mediated by µ and delta2 opioid receptors activation and preservation of mitochondrial function.

Asunto(s)

Hipoxia/fisiopatología , Mitocondrias Cardíacas/fisiología , Daño por Reperfusión Miocárdica/fisiopatología , Receptores Opioides delta/fisiología , Receptores Opioides mu/fisiología , Animales , Masculino , Mitocondrias Cardíacas/efectos de los fármacos , Daño por Reperfusión Miocárdica/prevención & control , Antagonistas de Narcóticos/farmacología , Técnicas de Cultivo de Órganos , Ratas , Ratas Wistar , Receptores Opioides delta/antagonistas & inhibidores , Receptores Opioides mu/antagonistas & inhibidores

RESUMEN

The objectives of this study were to investigate the role of endogenous opioids in the mediation of stress-induced cardiomyopathy (SIC), and to evaluate which opioid receptors regulate heart resistance to immobilization stress. Wistar rats were subjected to 24 h immobilization stress. Stress-induced heart injury was assessed by 99mTc-pyrophosphate accumulation in the heart. The opioid receptor (OR) antagonists (naltrexone, NxMB - naltrexone methyl bromide, MR 2266, ICI 174.864) and agonists (DALDA, DAMGO, DSLET, U-50,488) were administered intraperitoneally prior to immobilization and 12 h after the start of stress. In addition, the selective micro OR agonists PL017 and DAMGO were administered intracerebroventricularly prior to stress. Finally pretreatment with guanethidine was used. Naltrexone did not alter the cardiac 99mTc-PP accumulation in stressed rats. NxMB aggravated stress-induced cardiomyopathy (P=0.005) (SIC). The selective micro OR agonist DALDA, which does not cross the blood-brain barrier, completely prevented (P=0.006) SIC. The micro OR agonist DAMGO exhibited weaker effect than DALDA. The selective delta ligand (DSLET) and kappa OR ligand (U-50,488) did not alter stress-induced 99mTc-pyrophosphate accumulation in the heart. Intracerebroventricular administration of the micro OR agonists aggravated SIC. Pretreatment with guanethidine abolished this effect (P=0.01). Guanethidine alone exhibited cardioprotective properties. A stimulation of central micro OR promotes an appearance of SIC. In contrast, stimulation of peripheral micro OR contributes to an increase in cardiac tolerance to stress.

Asunto(s)

Analgésicos Opioides/uso terapéutico , Cardiotónicos/uso terapéutico , Cardiopatías/metabolismo , Cardiopatías/prevención & control , Miocardio/metabolismo , Estrés Psicológico/metabolismo , Analgésicos Opioides/farmacología , Animales , Cardiotónicos/farmacología , Encefalina Ala(2)-MeFe(4)-Gli(5)/farmacología , Encefalina Ala(2)-MeFe(4)-Gli(5)/uso terapéutico , Cardiopatías/inducido químicamente , Inmovilización/efectos adversos , Inmovilización/psicología , Masculino , Naltrexona/farmacología , Antagonistas de Narcóticos/farmacología , Ratas , Ratas Wistar , Receptores Opioides mu/agonistas , Receptores Opioides mu/metabolismo , Estrés Psicológico/psicología

RESUMEN

The study aimed at investigation of the role of opioid receptor (OR) in regulation of cardiac tolerance to ischemia-reperfusion. Opioid receptor ligands and inhibitors were administered in vivo prior to coronary artery occlusion (45 min) and reperfusion (2 hrs). Occurring infraction size/area at risk (IS/AAR) ratio was determined. Pretreatment with the micro-OR agonists DAMGO and dermorphin H exerted no effect on the IS/AAR ratio. Activation of delta 1-OR by DPDPE did not alter cardiac tolerance in ischemia-reperfusion either. Pretreatment with the delta 2-OR agonists deltorphin D and deltorphin E or ORL1 receptor agonist nociceptin exerted no effect on the IS/AAR ratio. Stimulation of K-OR by selective agonists did not modify cardiac tolerance to ischemia-reperfusion. The delta 2-OR agonist deltorphin II significantly reduced the IS/AAR index. This effect was prevented by treatment with naltrexone, naloxone methiodide and the delta 2-OR antagonist naltriben but not by the delta 1-OR antagonist BNTX. The infarction-limiting effect of deltorphin II was also abolished by inhibition of protein kinase C (PKC) and mitochondrial Katp channels. Thus, the agonists of micro, delta 1, kappa, and ORL1 receptors in used doses did not affect cardiac tolerance in ischemia-reperfusion injury in vivo. The peripheral delta 2-OR activation induces infarction size reduction. Its infarction-reducing effect of deltorphin II is mediated via PKC activation and mitochondrial Katp, channel opening.

Asunto(s)

Infarto del Miocardio/metabolismo , Daño por Reperfusión Miocárdica/metabolismo , Miocardio/metabolismo , Receptores Opioides/metabolismo , Analgésicos Opioides/farmacología , Animales , Cardiotónicos/farmacología , Modelos Animales de Enfermedad , Hemodinámica/efectos de los fármacos , Canales KATP/metabolismo , Masculino , Infarto del Miocardio/etiología , Infarto del Miocardio/fisiopatología , Infarto del Miocardio/prevención & control , Daño por Reperfusión Miocárdica/complicaciones , Daño por Reperfusión Miocárdica/fisiopatología , Antagonistas de Narcóticos/farmacología , Ratas , Ratas Wistar , Receptores Opioides/agonistas

RESUMEN

Ten-minute perfusion of intact isolated rat heart with Krebs-Henseleit solution containing delta-opioid receptor agonists (DPDPE, (-)-TAN-67) or delta-opioid receptor antagonists (naltrindole, TIPP[psi], ICI 174,864) at a final concentration of 0.1 mg/liter decreased HR, blood pressure in the left ventricle, and the rates of myocardial contraction and relaxation. Intravenous injection of delta-agonists (DPDPE, (-)-TAN-67, deltorphin II) or delta-antagonists (naltrindole, TIPP[psi], ICI 174,864) decreased HR in narcotized rats. Naloxone and naltrexone produced no effect on contractility and HR both in vivo and in vitro. Preliminary injection of naloxone and naltrexone did not prevent the negative chronotropic effect of ICI 174,864 in vitro. The negative inotropic and chronotropic effects of delta-opioid receptor antagonists are mediated by unknown non-opioid receptors in the heart.

Asunto(s)

Cardiotónicos/farmacología , Miocardio/metabolismo , Miocardio/patología , Receptores Opioides delta/antagonistas & inhibidores , Receptores Opioides/metabolismo , Animales , Presión Sanguínea , Ligandos , Contracción Miocárdica , Naloxona/farmacología , Naltrexona/farmacología , Perfusión , Ratas , Ratas Wistar , Disfunción Ventricular Izquierda

RESUMEN

Preliminary selective blockade of micro, delta1, delta2, kappa1, and kappa2 opioid receptors proved to have no effect on the incidence of ventricular arrhythmias during a 10-min coronary occlusion and subsequent reperfusion in ketamine-anesthetized rats. We propose that the endogenous opioid system has no considerable role in regulation of heart resistance to the arrhythmogenic effect of short-term local ischemia and subsequent reperfusion.

Asunto(s)

Cardiopatías/metabolismo , Miocardio/metabolismo , Péptidos Opioides/metabolismo , Receptores Opioides/metabolismo , Animales , Antagonistas de Narcóticos/administración & dosificación , Ratas , Ratas Wistar

RESUMEN

Preliminary selective block of mu-, delta1-, delta2-, and kappa-opioid receptors had no effect on the incidence of ventricular arrhythmias during 10-min coronary occlusion-reperfusion in ketamine-narcotized rats. Repetitive short-term immobilization of rats for 2 weeks improved heart resistance to the arrhythmogenic action of coronary occlusion and reperfusion. Selective mu-opioid receptor antagonist CTAP completely abolished, while selective delta- and kappa-opioid receptor antagonists did not modulate the antiarrhythmic effect of adaptation. Probably, endogenous agonists of mu-opioid receptors play an important role in the adaptive improvement of heart resistance to arrhythmogenic factors, but are insignificant for the modulation of heart resistance to the arrhythmogenic action of short-term local ischemia-reperfusion in non-adapted animals.

Asunto(s)

Arritmias Cardíacas/etiología , Corazón/fisiopatología , Daño por Reperfusión Miocárdica/fisiopatología , Péptidos Opioides/fisiología , Receptores Opioides/agonistas , Adaptación Fisiológica , Animales , Arritmias Cardíacas/fisiopatología , Corazón/efectos de los fármacos , Daño por Reperfusión Miocárdica/complicaciones , Antagonistas de Narcóticos/farmacología , Ratas

RESUMEN

OBJECTIVE: delta-Opioid receptors are involved in the cardioprotective effect of ischemic preconditioning. This study was designed (1) to assess the protective capacities of ischemic preconditioning and the synthetic delta-opioid receptor agonist D-Ala(2)-D-Leu(5) enkephalin (DADLE) in a functionally oriented experimental model of ischemia and reperfusion and (2) to assess whether the effects of both protective measures are similarly blocked by naloxone, a nonspecific delta-opioid receptor antagonist. METHODS: Sixty-four isolated working rat hearts were subjected to 45 minutes of hypothermic ischemia at 30 degrees C followed by 25 minutes of normothermic reperfusion. Rats were pretreated with DADLE (1 mg/kg body weight intravenously), naloxone (3 mg/kg body weight intravenously), or a combination thereof within 60 minutes before onset of isolated heart perfusion. During the preischemic perfusion period, 8 hearts per group were preconditioned by one cycle of 5 minutes of normothermic global ischemia and subsequent reperfusion whereas another 8 served as nonpreconditioned controls. The postischemic functional recovery of hearts and their creatine kinase leakage were determined. RESULTS: Pretreatment with DADLE and ischemic preconditioning improved the postischemic recovery of aortic flow when compared with nonpreconditioning (57.7% +/- 4.0% and 60.8% +/- 4.3% vs 40.0% +/- 4.2% of preischemic baseline value, P <.001). Combined pretreatment with DADLE before ischemic preconditioning afforded additional aortic flow recovery compared with pretreatment with DADLE alone (68.6% +/- 3.3% vs 57.7% +/- 4.0% of preischemic baseline value; P =.038). With combined pretreatment, early postischemic creatine kinase release was lower than control in hearts without pretreatment (0.48 +/- 0.11 vs 0.80 +/- 0.12 IU/5 minutes per heart; P =.001). Naloxone abolished the beneficial functional effects of pretreatment with DADLE and ischemic preconditioning. CONCLUSIONS: Pharmacologic activation of delta-opioid receptors affords improvement of functional protection in isolated working rat hearts similar to that conferred by classic ischemic preconditioning. The combination of both pretreatments reduces ischemic cellular damage and further adds to postischemic functional recovery. These changes are reversed by naloxone, an observation providing evidence that ischemic preconditioning involves signaling through opioid receptors.

Asunto(s)

Leucina Encefalina-2-Alanina/farmacología , Precondicionamiento Isquémico Miocárdico , Daño por Reperfusión Miocárdica/prevención & control , Receptores Opioides delta/efectos de los fármacos , Animales , Masculino , Naloxona/farmacología , Antagonistas de Narcóticos/farmacología , Ratas , Ratas Wistar , Receptores Opioides delta/antagonistas & inhibidores , Receptores Opioides delta/fisiología

RESUMEN

BACKGROUND: Opioid receptor agonists are involved in ischemic preconditioning and natural hibernation. The aim of this study was to determine whether pretreatment with D-Ala2-Leu5-enkephalin or morphine confers cardioprotection in large mammalian hearts. We assessed myocardial functional recovery and global energy metabolism after ischemic cold storage. METHODS: After pretreatment with D-Ala2-Leu5-enkephalin, morphine sulfate, or saline (n = 6 each), swine hearts were excised and stored for 75 minutes at 4 degrees C, then reperfused in a four-chamber isolated working heart apparatus. Serial myocardial biopsies were performed to assess cellular energy metabolism. RESULTS: Improved systolic (cardiac output, contractility) and diastolic (tau) left ventricular functions were observed in hearts pretreated with D-Ala2-Leu5-enkephalin or morphine. These benefits were not correlated with changes in high-energy phosphate levels. Cardiac enzyme leakage (creatine kinase, troponin-I) was similar among treated and control groups. Lactate efflux increased significantly in controls, but not in opioid-pretreated hearts (p < 0.01) at 75 minutes of reperfusion. CONCLUSIONS: D-Ala2-Leu5-enkephalin and morphine pretreatments improve postischemic function after cold storage of swine hearts. Postischemic lactate reduction, but not high-energy phosphate levels, may account for the observed cardioprotective effects.

Asunto(s)

Metabolismo Energético , Leucina Encefalina-2-Alanina/farmacología , Precondicionamiento Isquémico Miocárdico , Morfina/farmacología , Miocardio/metabolismo , Animales , Porcinos

RESUMEN

BACKGROUND: Mammalian hibernation biology is now known to be mediated by delta opioids. The altered myocellular physiology of hibernation closely parallels that of hypothermic ischemia used to protect the heart for cardiac surgery. METHODS AND RESULTS: The present study examined the interaction of delta opioid agonists and antagonists on myocardial tolerance to ischemia. By means of a nonhibernating isolated rabbit heart model, functional and metabolic myocardial parameters were assessed during nonischemic baseline and postischemic recovery periods. Control hearts with standard cardioplegic protection alone were compared with those with cardioplegia plus preperfusion with a delta opioid agonist, a delta opioid antagonist, or both. All hearts were then subjected to 2 hours of global ischemia. Compared with cardioplegia alone, postischemic left ventricular developed pressure, coronary flows, and myocardial oxygen consumption were all increased with administration of delta opioid agonists and decreased below baseline with delta opioid antagonists. Functional recovery of left ventricular developed pressure was improved with opioids (control hearts: 36 +/- 3 mm Hg vs hearts with cardioplegia plus delta opioid agonist: 65 +/- 5 mm Hg, P <.01) and inhibited with antagonists (control hearts: 36 +/- 3 mm Hg vs hearts with cardioplegia plus delta opioid antagonist: 17 +/- 5 mm Hg, P <.05), and true to form, the protective opioid effect was negated when combined with an antagonist (control hearts: 36 +/- 3 mm Hg vs hearts with cardioplegia plus delta opioid agonist and delta opioid antagonist: 42 +/- 4 mm Hg, P = not significant). CONCLUSIONS: This study demonstrates that cardiac tolerance to ischemia may be mediated by delta opioids.

Asunto(s)

Analgésicos Opioides/uso terapéutico , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Modelos Animales de Enfermedad , Isquemia Miocárdica/etiología , Isquemia Miocárdica/prevención & control , Naltrexona/análogos & derivados , Antagonistas de Narcóticos/uso terapéutico , Receptores Opioides delta/agonistas , Receptores Opioides delta/antagonistas & inhibidores , Analgésicos Opioides/farmacología , Animales , Compuestos de Bencilideno/farmacología , Compuestos de Bencilideno/uso terapéutico , Circulación Coronaria/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Encefalina D-Penicilamina (2,5)/farmacología , Encefalina D-Penicilamina (2,5)/uso terapéutico , Paro Cardíaco Inducido/métodos , Hipotermia Inducida/métodos , Precondicionamiento Isquémico Miocárdico , Isquemia Miocárdica/diagnóstico , Isquemia Miocárdica/metabolismo , Isquemia Miocárdica/fisiopatología , Naltrexona/farmacología , Naltrexona/uso terapéutico , Antagonistas de Narcóticos/farmacología , Tamaño de los Órganos , Consumo de Oxígeno/efectos de los fármacos , Conejos , Receptores Opioides delta/fisiología , Recuperación de la Función/efectos de los fármacos , Volumen Sistólico/efectos de los fármacos , Presión Ventricular/efectos de los fármacos

RESUMEN

OBJECTIVE: This study compared susceptibility to oxidation of low-density lipoproteins (LDL) of non-diabetic and diabetic (Type 2) men and examined the response of diabetic men to antioxidant supplementation (alpha-tocopherol, beta-carotene and ascorbate). RESEARCH DESIGN AND METHODS: Twenty adult non-diabetic and 20 diabetic men were recruited. Oxidation of LDL was assessed by four different assay systems, and the extent of oxidation was assessed by four different measurements. Diabetic men received eight weeks of placebo ("baseline"), twelve weeks of antioxidant supplements ("treated") and eight weeks of placebo ("post-treatment"). Supplements provided 24 mg of beta-carotene, 1000 mg of ascorbate and 800 IU of alpha-tocopherol daily. RESULTS: With Cu oxidation at 37 degrees C, thiobarbituric reactive substances (TBARS) formation was significantly higher (p=0.032) and loss of free amine groups was significantly greater (p=0.013) in the LDL from diabetic subjects than controls. Antioxidant supplementation of diabetic subjects significantly decreased all parameters of LDL oxidation with Cu at 30 degrees C and 37 degrees C. At 30 degrees C the lag phase increased from 55 to 129 minutes (p<0.0001); conjugated diene formation decreased from 1.23 to 0.62 OD units (p<0.0001); TBARS formation decreased from 78 to 33 nmoles MDA/mg LDL protein (p<0.0001); and free amine loss decreased from 41 to 12% (p<0.0001). With Cu oxidation at 37 degrees C, similar changes occurred. CONCLUSIONS: These studies indicate that the LDL from diabetic subjects are more susceptible to oxidation than LDL from non-diabetic subjects. Supplementation of diabetic subjects with antioxidant vitamins significantly decreases susceptibility of LDL to oxidation by Cu. These studies are consistent with epidemiological and intervention studies suggesting that antioxidant vitamin use significantly decreases risk for coronary heart disease.

Asunto(s)

Antioxidantes/administración & dosificación , Diabetes Mellitus Tipo 2/sangre , Suplementos Dietéticos , Peroxidación de Lípido , Lipoproteínas LDL/sangre , Adulto , Anciano , Animales , Ácido Ascórbico/administración & dosificación , Células Cultivadas , Cobre , Humanos , Lipoproteínas LDL/metabolismo , Macrófagos Peritoneales/metabolismo , Masculino , Ratones , Persona de Mediana Edad , Oxidación-Reducción , Método Simple Ciego , Vitamina E/administración & dosificación , beta Caroteno/administración & dosificación

RESUMEN

BACKGROUND: Water-soluble dietary fibers decrease postprandial glucose concentrations and decrease serum cholesterol concentrations. This study examined the effects of administering psyllium to men with type 2 diabetes. OBJECTIVE: The objective was to evaluate the safety and effectiveness of psyllium husk fiber used adjunctively to a traditional diet for diabetes in the treatment of men with type 2 diabetes and mild-to-moderate hypercholesterolemia. DESIGN: After a 2-wk dietary stabilization phase, 34 men with type 2 diabetes and mild-to-moderate hypercholesterolemia were randomly assigned to receive 5.1 g psyllium or cellulose placebo twice daily for 8 wk. Serum lipid and glycemic indexes were evaluated biweekly on an outpatient basis and at weeks 0 and 8 in a metabolic ward. RESULTS: In the metabolic ward, the psyllium group showed significant improvements in glucose and lipid values compared with the placebo group. Serum total and LDL-cholesterol concentrations were 8.9% (P < 0.05) and 13.0% (P = 0.07) lower, respectively, in the psyllium than in the placebo group. All-day and postlunch postprandial glucose concentrations were 11.0% (P < 0.05) and 19.2% (P < 0.01) lower in the psyllium than in the placebo group. Both products were well tolerated, with no serious adverse events related to treatment reported in either group. CONCLUSION: The addition of psyllium to a traditional diet for persons with diabetes is safe, is well tolerated, and improves glycemic and lipid control in men with type 2 diabetes and hypercholesterolemia.

Asunto(s)

Glucemia/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Hipercolesterolemia/metabolismo , Lípidos/sangre , Psyllium/uso terapéutico , Adulto , Anciano , Apolipoproteína A-I/sangre , Apolipoproteína B-100 , Apolipoproteínas B/sangre , Glucemia/análisis , Colesterol/sangre , HDL-Colesterol/sangre , LDL-Colesterol/sangre , VLDL-Colesterol/sangre , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Dieta para Diabéticos , Método Doble Ciego , Humanos , Hipercolesterolemia/complicaciones , Hipercolesterolemia/tratamiento farmacológico , Insulina/sangre , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Psyllium/normas , Radioinmunoensayo , Triglicéridos/sangre

RESUMEN

BACKGROUND: Hypothermic cardioplegia provides myocellular protection, yet postischemic dysfunction remains a significant problem. Interestingly, the subcellular changes in hibernation parallel the altered biology of induced cardiac ischemia but are well tolerated by hibernated mammalian myocardium. An uncharacterized factor derived from hibernating animals, hibernation induction trigger (HIT), has been shown to induce hibernation in active animals and afford myocardial protection after ischemia-reperfusion injury. Therefore, it was of interest to further characterize the cardioprotective effects of HIT in the setting of ischemia-reperfusion injury. METHODS AND RESULTS: To determine whether HIT could improve myocardial recovery after global ischemia, isolated rabbit hearts received either standard cardioplegia or HIT in the cardioplegia or underwent preperfusion with HIT before cardioplegia. Alternatively, to determine whether HIT requires metabolic alteration, additional rabbits had in vivo pretreatment with HIT from 15 minutes to 5 days before ischemia. All hearts underwent 2 hours of global ischemia at 34 degrees C. Recovery of postischemic isovolumic developed pressure, coronary flows, and MVO2 were compared. Compared with vehicle pretreatment, HIT pretreatment (1 hour) significantly enhanced indexes of functional recovery, including developed pressure (38 +/- 3 versus 69 +/- 7 mm Hg) and coronary flow (46 +/- 2 versus 82 +/- 11 mL/min). In addition, ultrastructural morphology was preserved but only with in vivo pretreatment. Liver protein content was not increased in rabbits treated from 12 hours to 5 days with HIT versus controls, belying a protein neosynthesis mechanism. However, the temporal sequences suggested conversion of an inactive HIT profactor to an active form. CONCLUSIONS: Administration of serum derived from hibernating black bears to rabbits affords protection against ischemia-reperfusion injury compared with vehicle (saline)-treated animals in a rabbit isolated heart preparation. It is apparent that HIT deserves further identification and mechanistic study in the setting of ischemia-reperfusion injury.

Asunto(s)

Corazón/fisiopatología , Hibernación/fisiología , Ursidae/fisiología , Animales , Femenino , Masculino , Isquemia Miocárdica/fisiopatología , Daño por Reperfusión Miocárdica/fisiopatología , Conejos , Factores de Tiempo , Ursidae/sangre

RESUMEN

Previous studies show that infusion of hibernating woodchuck albumin (HWA) induces hibernation in summer-active ground squirrels and results in profound behavioral and physiological depression in primates. These effects are reversed by the administration of opiate antagonists, suggesting that the putative hibernation induction trigger (HIT) may act through opioid receptors. We have demonstrated that both HIT-containing plasma and the synthetic alpha opioid D-Ala2-D-Leu5-enkephalin (DADLE), which mimics the activity of HIT in hibernators, extend tissue survival time of a multi-organ autoperfusion system by 3-fold. In this study we present the first data showing biological activity with a much more highly purified plasma fraction from hibernating woodchucks, identified as the hibernation-related factor (HRF). Both the HRF and DADLE show opiate-like contractile inhibition in the mouse vas deferens (Mvd) bioassay. We also have preliminary evidence in an isolated rabbit heart preparation indicating that the HRF and DADLE act similarly to restore left ventricular function following global myocardial ischemia. Furthermore, we have partially sequenced an alpha 1-glycoprotein-like 88 kDa hibernation-related protein (p88 HRP) present in this fraction, which may prove to be the blood-borne HIT molecule.

Asunto(s)

Proteínas Sanguíneas/química , Glicoproteínas/química , Hibernación/fisiología , Marmota/fisiología , Narcóticos/sangre , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Electroforesis en Gel de Poliacrilamida , Leucina Encefalina-2-Alanina/farmacología , Hígado/metabolismo , Masculino , Datos de Secuencia Molecular , Unión Proteica/fisiología , ARN Mensajero/metabolismo , Receptores Opioides delta/metabolismo , Alineación de Secuencia , Análisis de Secuencia , Conducto Deferente/efectos de los fármacos

RESUMEN

Studies have shown that plasma albumin fractions (PAFs) from hibernating mammals can inhibit induced contractility of the guinea pig ileum similarly to morphine. This study examined PAFs from two species of prairie dogs, one that undergoes natural seasonal hibernation (white-tailed, WT) and one that does not but can be induced to hibernate (black-tailed, BT). Dose-response curves of lyophilized PAF yielded IC50 values (mg) of 20.23 for summer WT, 15.53 for hibernating WT, 15.45 for summer BT, and 13.16 for winter-active BT. Winter samples from both species have IC50s lower than samples from summer animals, indicating greater potency of winter PAFs in suppressing guinea pig ileum contractility and therefore the presence of more opioid ligands in winter prairie dog plasma. Studies to elucidate receptor selectivity of PAF continue.

Asunto(s)

Hibernación/fisiología , Íleon/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Receptores Opioides/efectos de los fármacos , Sciuridae/fisiología , Albúmina Sérica/farmacología , Animales , Relación Dosis-Respuesta a Droga , Cobayas , Técnicas In Vitro , Masculino , Contracción Muscular/efectos de los fármacos , Plexo Mientérico/efectos de los fármacos , Plexo Mientérico/fisiología , Especificidad de la Especie

RESUMEN

Involvement of opioid molecules in hibernation is well established, with the delta opioid receptor implicated in hibernation induction. Previous studies have shown that plasma albumin fractions (PAFs) from hibernating mammals contain an uncharacterized ligand called "hibernation-induction trigger" (HIT), which causes inhibition of induced contractility in the guinea pig ileum (GPI). In part I of this study, we described effects of PAF from two species of prairie dogs on induced contractility of the GPI. In the present study (part II), we examine the response of the mouse vas deferens (MVD), which is populated with the delta receptor subtype, to increasing concentrations of PAF from the white-tailed prairie dog (WT) and the black-tailed prairie dog (BT). Dose-response curves of lyophilized PAF yielded IC50 values (mg) (mean dose that inhibits contractility to 50% of control) of 11.0 for summer WT, 10.6 for hibernating WT, 9.4 for summer BT, 12.2 for winter active BT, and 4.7 for winter hibernating BT. These results suggest that delta opioid (HIT) is present in both species throughout the calendar year and that the induction of hibernation may involve not only levels of opioid but also dynamic interactions between endogenous opioid and its receptors.

Asunto(s)

Hibernación/fisiología , Músculo Liso/efectos de los fármacos , Receptores Opioides delta/efectos de los fármacos , Sciuridae/fisiología , Albúmina Sérica/farmacología , Conducto Deferente/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Íleon/efectos de los fármacos , Técnicas In Vitro , Masculino , Ratones , Contracción Muscular/efectos de los fármacos , Plexo Mientérico/efectos de los fármacos , Plexo Mientérico/fisiología , Especificidad de la Especie

RESUMEN

BACKGROUND: Hypothermic cardioplegia provides adequate myocellular protection, yet stunning and dysfunction remain significant problems. Interestingly, the subcellular changes of hibernation parallel the altered biology of induced cardiac ischemia, but are well tolerated by hibernating mammalian myocardium. Hibernation induction trigger (HIT) from winter-hibernating animal serum induces hibernation in active animals. Hibernation induction trigger is opiate in nature and is similar to the delta 2 opioids. METHODS: To determine whether HIT could improve myocardial recovery following global ischemia, we gave 37 isolated rabbit hearts either standard cardioplegia or cardioplegia containing summer-active woodchuck, hibernating woodchuck, or black bear HIT serum or a delta 2 opioid, D-Ala2-Leu5-enkephalin, before 2 hours of global ischemia. RESULTS: Hibernation induction trigger appeared not to have an active mechanism during ischemia, as all hearts had equal recovery. In contrast, when examining for a preischemia mechanism, 23 additional rabbits received 3 days pretreatment with summer-active woodchuck or HIT hibernating woodchuck or black bear serum, or were preperfused with D-Ala2-Leu5-enkephalin or D-pen2,5-enkephalin, a-delta 1 opioid, again before 2 hours of global ischemia. Postischemic ventricular function, coronary flows, myocardial oxygen consumption, and ultrastructural preservation were all significantly improved with HIT and D-Ala2-Leu5-enkephalin pretreatment. CONCLUSION: "Natural" HIT protection is superior to standard cardioplegia alone and may have clinical application.

Asunto(s)

Corazón/efectos de los fármacos , Hibernación/fisiología , Proteínas/farmacología , Análisis de Varianza , Animales , Circulación Coronaria/efectos de los fármacos , Modelos Animales de Enfermedad , Encefalina D-Penicilamina (2,5) , Leucina Encefalina-2-Alanina/administración & dosificación , Leucina Encefalina-2-Alanina/clasificación , Leucina Encefalina-2-Alanina/farmacología , Encefalinas/administración & dosificación , Encefalinas/farmacología , Femenino , Paro Cardíaco Inducido , Hipotermia Inducida , Masculino , Marmota , Isquemia Miocárdica/fisiopatología , Aturdimiento Miocárdico/etiología , Aturdimiento Miocárdico/fisiopatología , Miocardio/metabolismo , Miocardio/ultraestructura , Consumo de Oxígeno/efectos de los fármacos , Péptidos , Premedicación , Proteínas/administración & dosificación , Proteínas/clasificación , Conejos , Receptores Opioides delta/agonistas , Ursidae , Función Ventricular/efectos de los fármacos , Función Ventricular Izquierda/efectos de los fármacos , Presión Ventricular/efectos de los fármacos

RESUMEN

BACKGROUND: Consistent clinical results have not been achieved when lung preservation times exceed 6 hours. The aim of this study was to use an alternative normothermic autoperfusion technique for lung preservation and transplantation. METHODS: In six paired dogs, donor lungs were removed, along with the heart, liver, pancreas, duodenum, and both kidneys, and were preserved for 24 to 33 hours in a normothermic autoperfused multiple organ block. Orthotopic left lung transplantation was performed at the end of the preservation period. RESULTS: Lung function was good during the preservation period. With a gas mixture of 50% O2 + 3% CO2 + 47% N2 delivered to the multiorgan block, arterial oxygen tension ranged from 331 +/- 19 to 383 +/- 8 mm Hg; carbon dioxide tension ranged from 18 +/- 5 to 32 +/- 5 mm Hg; and pH ranged from 7.36 +/- 0.02 to 7.45 +/- 0.08. After transplantation, the dogs were kept anesthetized and ventilated for 24 hours with the same gas mixture. The opposite pulmonary artery was occluded 0 to 6 hours after transplantation. Arterial blood pressures were stable after surgery. Arterial oxygen tension was maintained between 205 +/- 39 and 320 +/- 57 mm Hg, and arterial carbon dioxide tension was maintained between 23 +/- 2 and 34 +/- 2 mm Hg. Lung tissue wet/dry weight ratio was 4.94 +/- 0.17 after preservation; this ratio did not differ from that found in normal controls (4.91 +/- 0.10). CONCLUSIONS: This study shows that the lungs were well preserved for more than 24 hours of preservation when the normothermic multiorgan block preparation was used. The transplanted left lung was able to support the anesthetized dog after the opposite pulmonary artery was occluded.

Asunto(s)

Trasplante de Pulmón/fisiología , Preservación de Órganos/métodos , Oxígeno/sangre , Intercambio Gaseoso Pulmonar/fisiología , Pruebas de Función Respiratoria , Animales , Dióxido de Carbono/sangre , Perros , Complicaciones Posoperatorias/fisiopatología , Temperatura , Factores de Tiempo , Función Ventricular Izquierda/fisiología

RESUMEN

Cardiac transplant is hindered by donor shortage and preservation time. Extended extracorporeal preservation could increase the number and distribution of hearts for transplantation. Interestingly, mammalian hibernation biology closely parallels the altered cardiac cellular physiology noted with hypothermic organ storage. The present study undertook to test whether treatment with hibernation induction triggers could improve myocardial functional recovery following prolonged ischemic storage in a nonhibernating mammalian model. To study this hypothesis, isolated rabbit hearts had baseline functional and metabolic parameters recorded and then received either hypothermic storage only or standard cardioplegia, or cardioplegia containing 1 mg/kg D-Ala2-Leu5-enkaphalin (DADLE), which mimics natural hibernation, or preperfusion with DADLE, administered for 15 min at 2 mmol, 25 min prior to cardioplegic ischemia. Hearts were then subjected to 18 hr of global ischemic storage at 4 degrees C. Isovolumic developed pressure, coronary flows, and myocardial oxygen consumption were significantly improved with DADLE pretreatment vs. all groups after storage and reflow. Furthermore, DADLE hearts demonstrated better histological ultrastructure preservation following prolonged storage ischemia. This study demonstrates that hibernation protection with DADLE is beneficial for prolonged cardiac storage. The use of hibernation induction triggers is promising for organ preservation and deserve further mechanistic study.

Asunto(s)

Leucina Encefalina-2-Alanina/farmacología , Trasplante de Corazón/fisiología , Corazón , Hibernación , Isquemia Miocárdica , Reperfusión Miocárdica , Preservación de Órganos/métodos , Análisis de Varianza , Animales , Soluciones Cardiopléjicas , Femenino , Corazón/efectos de los fármacos , Corazón/fisiología , Masculino , Conejos , Factores de Tiempo

RESUMEN

BACKGROUND: The complications of preserving lungs for transplantation are well known, with successful transplantation only being assured by preservation times of 5 to 6 hours or less. If a new method of consistent lung preservation could be identified, lung transplantation could be extended to many patients. We have previously reported lung preservation times averaging 14.8 hours using a multiorgan autoperfusion block infused with physiologic saline solution as a model. When plasma from deeply hibernating woodchucks (Marmota monax) or the delta opioid DADLE was infused into the multi-organ block, lung preservation times increased threefold to 45 hours. METHODS: In this study, we examined the effect of infusing plasma containing the hibernation induction trigger molecule on lung preservation for transplantation using a multiorgan autoperfusion block. RESULTS: This study demonstrated that successful orthotopic transplantation of single canine lungs is possible after 24 to 33 hours of preservation when the lung has been maintained with plasma containing the hibernation induction trigger molecule. CONCLUSIONS: Theoretically, hibernation induction trigger could be administered to donors before lung harvest in an effort to extend lung preservation times.

Asunto(s)

Hibernación , Trasplante de Pulmón/métodos , Pulmón , Preservación de Órganos/métodos , Proteínas/uso terapéutico , Animales , Perros , Femenino , Hemodinámica , Trasplante de Pulmón/fisiología , Masculino , Péptidos , Pruebas de Función Respiratoria