RESUMO
BACKGROUND: Obesity is thought to increase renal hyperfiltration, thereby increasing albuminuria and the progression of renal disease. The effect of pharmacologically mediated weight loss on renal outcomes is not well-described. Lorcaserin, a selective serotonin 2C receptor agonist that promotes appetite suppression, led to sustained weight loss without any increased risk for major adverse cardiovascular (CV) events in the CAMELLIA-TIMI 61 trial (Cardiovascular and Metabolic Effects of Lorcaserin in Overweight and Obese Patients-Thrombolysis in Myocardial Infarction 61). METHODS: CAMELLIA-TIMI 61 randomly assigned 12 000 overweight or obese patients with or at high risk for atherosclerotic CV disease to lorcaserin or placebo on a background of lifestyle modification. The primary renal outcome was a composite of new or worsening persistent micro- or macroalbuminuria, new or worsening chronic kidney disease, doubling of serum creatinine, end-stage renal disease, renal transplant, or renal death. RESULTS: At baseline, 23.8% of patients had an estimated glomerular filtration rate (eGFR) <60 mL·min-1·1.73 m-2 and 19.0% had albuminuria (urinary albumin:creatinine ratio ≥30 mg/g). Lorcaserin reduced the risk of the primary renal composite outcome (4.2% per year versus 4.9% per year; hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.79-0.96; P=0.0064). The benefit was consistent across subpopulations at increased baseline CV and renal risk. Lorcaserin improved both eGFR and urinary albumin:creatinune ratio within the first year after randomization. The effect of lorcaserin on weight, hemoglobin A1c, and systolic blood pressure was consistent regardless of baseline renal function. Likewise, there was no excess in cardiovascular events in patients assigned to lorcaserin in comparison with placebo, regardless of renal function. After adjustment for baseline characteristics, those with evidence of kidney disease were at increased risk of major CV events. Compared with patients with an eGFR ≥90 mL·min-1·1.73 m-2, those with an eGFR 60-90 and those <60 mL·min-1·1.73 m-2 had HRs of 1.25 (95% CI, 1.01, 1.56) and 1.51 (95% CI, 1.17, 1.95), respectively ( P for trend 0.0015). Likewise, compared with patients with no albuminuria (<30 mg/g), those microalbuminuria and those with macroalbuminuria had HRs of 1.46 (95% CI, 1.22, 1.74) and 2.10 (95% CI, 1.58, 2.80), respectively ( P for trend <0.0001). CONCLUSIONS: Renal dysfunction was associated with increased CV risk in overweight and obese patients. When added to diet and lifestyle, lorcaserin reduced the rate of new-onset or progressive renal impairment in comparison with placebo. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02019264.
Assuntos
Depressores do Apetite/uso terapêutico , Regulação do Apetite/efeitos dos fármacos , Benzazepinas/uso terapêutico , Taxa de Filtração Glomerular/efeitos dos fármacos , Nefropatias/epidemiologia , Rim/efeitos dos fármacos , Obesidade/tratamento farmacológico , Agonistas do Receptor 5-HT2 de Serotonina/uso terapêutico , Depressores do Apetite/efeitos adversos , Benzazepinas/efeitos adversos , Biomarcadores/sangue , Pressão Sanguínea/efeitos dos fármacos , Dieta Redutora , Progressão da Doença , Método Duplo-Cego , Feminino , Hemoglobinas Glicadas/metabolismo , Humanos , Rim/metabolismo , Rim/fisiopatologia , Nefropatias/mortalidade , Nefropatias/fisiopatologia , Masculino , Pessoa de Meia-Idade , Obesidade/mortalidade , Obesidade/fisiopatologia , Obesidade/psicologia , Medição de Risco , Fatores de Risco , Comportamento de Redução do Risco , Agonistas do Receptor 5-HT2 de Serotonina/efeitos adversos , Fatores de Tempo , Resultado do Tratamento , Redução de Peso/efeitos dos fármacosRESUMO
BACKGROUND: There is a direct relationship between bodyweight and risk of diabetes. Lorcaserin, a selective serotonin 2C receptor agonist that suppresses appetite, has been shown to facilitate sustained weight loss in obese or overweight patients. We aimed to evaluate the long-term effects of lorcaserin on diabetes prevention and remission. METHODS: In this randomised, double-blind, placebo-controlled trial done in eight countries, we recruited overweight or obese patients (body-mass index ≥27 kg/m2) with or at high risk for atherosclerotic vascular disease. Eligible patients were aged 40 years or older; patients at high risk for atherosclerotic vascular disease had to be aged 50 years or older with diabetes and at least one other risk factor. Patients were randomly assigned to receive either lorcaserin (10 mg twice daily) or matching placebo. Additionally, all patients had access to a standardised weight management programme based on lifestyle modification. The prespecified primary metabolic efficacy endpoint of time to incident diabetes was assessed in patients with prediabetes at baseline. The prespecified secondary outcomes for efficacy were incident diabetes in all patients without diabetes, achievement of normoglycaemia in patients with prediabetes, and change in glycated haemoglobin (HbA1c) in patients with diabetes. Hypoglycaemia was a prespecified safety outcome. Analysis was by intention to treat, using Cox proportional hazard models for time-to-event analyses. This trial is registered with ClinicalTrials.gov, number NCT02019264. FINDINGS: Between Feb 7, 2014, and Nov 20, 2015, 12â000 patients were randomly assigned to lorcaserin or placebo (6000 patients in each group) and followed up for a median of 3·3 years (IQR 3·0-3·5). At baseline, 6816 patients (56·8%) had diabetes, 3991 (33·3%) prediabetes, and 1193 (9·9%) normoglycaemia. At 1 year, patients treated with lorcaserin had a net weight loss beyond placebo of 2·6 kg (95% CI 2·3-2·9) for those with diabetes, 2·8 kg (2·5-3·2) for those with prediabetes, and 3·3 kg (2·6-4·0) for those with normoglycaemia (p<0·0001 for all analyses). Lorcaserin reduced the risk of incident diabetes by 19% in patients with prediabetes (172 [8·5%] of 2015 vs 204 [10·3%] of 1976; hazard ratio 0·81, 95% CI 0·66-0·99; p=0·038) and by 23% in patients without diabetes (174 [6·7%] of 2615 vs 215 [8·4%] of 2569; 0·77, 0·63-0·94; p=0·012). Lorcaserin resulted in a non-significant increase in the rate of achievement of normoglycaemia in patients with prediabetes (185 [9·2%] vs 151 [7·6%]; 1·20, 0·97-1·49; p=0·093). In patients with diabetes, lorcaserin resulted in a reduction of 0·33% (95% CI 0·29-0·38; p<0·0001) in HbA1c compared with placebo at 1 year from a mean baseline of 53 mmol/mol (7·0%). In patients with diabetes at baseline, severe hypoglycaemia with serious complications was rare, but more common with lorcaserin (12 [0·4%] vs four [0·1%] events; p=0·054). INTERPRETATION: Lorcaserin decreases risk for incident diabetes, induces remission of hyperglycaemia, and reduces the risk of microvascular complications in obese and overweight patients, supporting the role of lorcaserin as an adjunct to lifestyle modification for chronic management of weight and metabolic health. FUNDING: Eisai.
Assuntos
Depressores do Apetite/uso terapêutico , Benzazepinas/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Obesidade/complicações , Idoso , Aterosclerose/complicações , Aterosclerose/tratamento farmacológico , Peso Corporal/efeitos dos fármacos , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/prevenção & controle , Método Duplo-Cego , Feminino , Hemoglobinas Glicadas/análise , Humanos , Masculino , Pessoa de Meia-Idade , Sobrepeso/complicações , Estado Pré-Diabético/complicações , Estado Pré-Diabético/tratamento farmacológico , Estado Pré-Diabético/prevenção & controle , Indução de Remissão , Redução de Peso/efeitos dos fármacosRESUMO
BACKGROUND: Lorcaserin, a selective serotonin 2C receptor agonist that modulates appetite, has proven efficacy for weight management in overweight or obese patients. The cardiovascular safety and efficacy of lorcaserin are undefined. METHODS: We randomly assigned 12,000 overweight or obese patients with atherosclerotic cardiovascular disease or multiple cardiovascular risk factors to receive either lorcaserin (10 mg twice daily) or placebo. The primary safety outcome of major cardiovascular events (a composite of cardiovascular death, myocardial infarction, or stroke) was assessed at an interim analysis to exclude a noninferiority boundary of 1.4. If noninferiority was met, the primary cardiovascular efficacy outcome (a composite of major cardiovascular events, heart failure, hospitalization for unstable angina, or coronary revascularization [extended major cardiovascular events]) was assessed for superiority at the end of the trial. RESULTS: At 1 year, weight loss of at least 5% had occurred in 1986 of 5135 patients (38.7%) in the lorcaserin group and in 883 of 5083 (17.4%) in the placebo group (odds ratio, 3.01; 95% confidence interval [CI], 2.74 to 3.30; P<0.001). Patients in the lorcaserin group had slightly better values with respect to cardiac risk factors (including blood pressure, heart rate, glycemic control, and lipids) than those in the placebo group. During a median follow-up of 3.3 years, the rate of the primary safety outcome was 2.0% per year in the lorcaserin group and 2.1% per year in the placebo group (hazard ratio, 0.99; 95% CI, 0.85 to 1.14; P<0.001 for noninferiority); the rate of extended major cardiovascular events was 4.1% per year and 4.2% per year, respectively (hazard ratio, 0.97; 95% CI, 0.87 to 1.07; P=0.55). Adverse events of special interest were uncommon, and the rates were generally similar in the two groups, except for a higher number of patients with serious hypoglycemia in the lorcaserin group (13 vs. 4, P=0.04). CONCLUSIONS: In a high-risk population of overweight or obese patients, lorcaserin facilitated sustained weight loss without a higher rate of major cardiovascular events than that with placebo. (Funded by Eisai; CAMELLIA-TIMI 61 ClinicalTrials.gov number, NCT02019264 .).
Assuntos
Fármacos Antiobesidade/uso terapêutico , Benzazepinas/uso terapêutico , Doenças Cardiovasculares/complicações , Hipoglicemia/induzido quimicamente , Obesidade/tratamento farmacológico , Sobrepeso/tratamento farmacológico , Redução de Peso/efeitos dos fármacos , Idoso , Fármacos Antiobesidade/efeitos adversos , Insuficiência da Valva Aórtica/induzido quimicamente , Benzazepinas/efeitos adversos , Doenças Cardiovasculares/induzido quimicamente , Doenças Cardiovasculares/epidemiologia , Diabetes Mellitus Tipo 2/complicações , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Hipertensão Pulmonar/induzido quimicamente , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Sobrepeso/complicações , Fatores de RiscoRESUMO
OBJECTIVES: Lorcaserin, a selective serotonin 2C receptor agonist, is an effective pharmacologic weight-loss therapy that improves several cardiovascular risk factors. The long-term clinical cardiovascular and metabolic safety and efficacy in patients with elevated cardiovascular risk are unknown. RESEARCH DESIGN AND METHODS: CAMELLIA-TIMI 61 (NCT02019264) is a randomized, double-blind, placebo-controlled, multinational clinical trial designed to evaluate the safety and efficacy of lorcaserin with regard to major adverse cardiovascular events and progression to diabetes in overweight or obese patients at high cardiovascular risk. Overweight or obese patients either with established cardiovascular disease or with diabetes and at least 1 other cardiovascular risk factor were randomized in a 1:1 ratio to lorcaserin 10 mg twice daily or matching placebo. The primary safety objective is to assess for noninferiority of lorcaserin for the composite end point of cardiovascular death, myocardial infarction, or stroke (major adverse cardiovascular event [MACE]) (with noninferiority defined as the upper bound of a 1-sided 97.5% CI excluding a hazard ratio of 1.4) compared with placebo assessed at an interim analysis with 460 adjudicated events. The efficacy objectives, assessed at study completion, will evaluate the superiority of lorcaserin for the primary composite end point of cardiovascular death, myocardial infarction, stroke, hospitalization for unstable angina, heart failure, or any coronary revascularization (MACE+) and the key secondary end point of conversion to diabetes. Recruitment began in January 2014 and was completed in November 2015 resulting in a total population of 12,000 patients. The trial is planned to continue until at least 1,401 adjudicated MACE+ events are accrued and the median treatment duration exceeds 2.5â¯years. CONCLUSION: CAMELLIA-TIMI 61 is investigating the safety and efficacy of lorcaserin for MACEs and conversion to diabetes in overweight or obese patients with established cardiovascular disease or multiple cardiovascular risk factors.
Assuntos
Fármacos Antiobesidade/uso terapêutico , Benzazepinas/uso terapêutico , Doenças Cardiovasculares/prevenção & controle , Obesidade/tratamento farmacológico , Sobrepeso/tratamento farmacológico , Agonistas do Receptor 5-HT2 de Serotonina/uso terapêutico , Idoso , Fármacos Antiobesidade/efeitos adversos , Fármacos Antiobesidade/farmacologia , Benzazepinas/efeitos adversos , Benzazepinas/farmacologia , Biomarcadores/análise , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/mortalidade , Diabetes Mellitus Tipo 2/complicações , Progressão da Doença , Método Duplo-Cego , Ecocardiografia , Humanos , Pessoa de Meia-Idade , Obesidade/complicações , Sobrepeso/complicações , Projetos de Pesquisa , Fatores de Risco , Agonistas do Receptor 5-HT2 de Serotonina/efeitos adversos , Agonistas do Receptor 5-HT2 de Serotonina/farmacologia , Redução de PesoRESUMO
Efficient induction of apoptosis requires not only the activation of death-promoting proteins but also the inactivation of inhibitors of cell death. ARC (apoptosis repressor with caspase recruitment domain) is an endogenous inhibitor of apoptosis that antagonizes both central apoptosis pathways. Despite its potent inhibition of cell death, cells that express abundant ARC eventually succumb. A possible explanation is that ARC protein levels decrease dramatically in response to death stimuli. The mechanisms that mediate decreases in ARC protein levels during apoptosis and whether these decreases initiate the subsequent cell death are not known. Here we show that endogenous ARC protein levels decrease in response to death stimuli in a variety of cell contexts as well as in a model of myocardial ischemia-reperfusion in intact mice. Decreases in ARC protein levels are not explained by alterations in the abundance of ARC transcripts. Rather, pulse-chase experiments show that decreases in steady state ARC protein levels during apoptosis result from marked destabilization of ARC protein. ARC protein destabilization, in turn, is mediated by the ubiquitin-proteasomal pathway, as mutation of ARC ubiquitin acceptor residues stabilizes ARC protein and preserves its steady state levels during apoptosis. In addition, this degradation-resistant ARC mutant exhibits improved cytoprotection. We conclude that decreases in ARC protein levels in response to death stimuli are mediated by increased ARC protein degradation via the ubiquitin-proteasomal pathway. Moreover, these data demonstrate that decreases in ARC protein levels are a trigger, and not merely a consequence, of the ensuing cell death.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Apoptose , Proteínas Musculares/metabolismo , Traumatismo por Reperfusão Miocárdica/enzimologia , Miocárdio/enzimologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitina/metabolismo , Animais , Apoptose/genética , Proteínas Reguladoras de Apoptose/genética , Células HeLa , Humanos , Masculino , Camundongos , Proteínas Musculares/genética , Mutação , Traumatismo por Reperfusão Miocárdica/genética , Miocárdio/patologiaRESUMO
BACKGROUND: Although the occurrence of cardiac myocyte apoptosis during heart failure has been documented, its importance in pathogenesis is unknown. Transgenic mice with cardiac-restricted overexpression of Galpha(q) exhibit a lethal, peripartum cardiomyopathy accompanied by apoptosis. To test whether apoptosis is causally linked to heart failure, we assessed whether inhibiting this cell death would improve left ventricular function and survival in the Galpha(q) peripartum cardiomyopathy model. METHODS AND RESULTS: The potent polycaspase inhibitor IDN-1965 or vehicle was administered subcutaneously to Galpha(q) mice by osmotic minipump beginning on day 12 of pregnancy and continuing through euthanasia at day 14 postpartum. As expected, IDN-1965 markedly suppressed cardiac caspase-3-like activity (86.5%; P<0.01), accompanied by reduction in the frequency of cardiac myocyte apoptosis from 1.9+/-0.3% to 0.2+/-0.1% (P<0.01). Animals receiving IDN-1965 exhibited significant improvements in left ventricular end-diastolic dimension (vehicle, 4.7+/-0.1 mm; IDN-1965, 4.2+/-0.1 mm; P<0.01), fractional shortening (vehicle, 30.7+/-1.2%; IDN-1965, 38.9+/-1.0%; P<0.01), positive (vehicle, 3972+/-412; IDN-1965, 5870+/-295; P<0.01) and negative (vehicle, 2365+/-213; IDN-1965, 3413+/-201; P<0.01) dP/dt, and complete suppression of mortality (vehicle, 6 of 20 died; IDN-1965, 0 of 14 died; P<0.05). CONCLUSIONS: Reduction in cardiac myocyte apoptosis by caspase inhibition improved left ventricular function and survival in pregnant Galpha(q) mice. These data indicate that cardiac myocyte apoptosis plays a causal role in the pathogenesis of cardiomyopathy in this model. Caspase inhibition may provide a novel therapeutic target for heart failure.
Assuntos
Apoptose , Cardiomiopatia Dilatada/etiologia , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/genética , Miócitos Cardíacos/patologia , Animais , Cardiomiopatia Dilatada/patologia , Cardiomiopatia Dilatada/fisiopatologia , Caspase 3 , Inibidores de Caspase , Caspases/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , Feminino , Ventrículos do Coração/diagnóstico por imagem , Indóis/farmacologia , Camundongos , Camundongos Transgênicos , Oligopeptídeos/farmacologia , Período Pós-Parto , Gravidez , Análise de Sobrevida , Ultrassonografia , Função Ventricular EsquerdaRESUMO
BACKGROUND: The timely reperfusion of ischemic myocardium limits infarction, but components of reperfusion, such as inflammation, may be injurious. The chemokine receptor CXCR2 mediates neutrophil chemotaxis. CXCR2 activation also inhibits hypoxia-induced death of isolated cardiac myocytes. This study assesses whether CXCR2 mediates protection in the intact heart and, if so, the magnitude of this protection relative to CXCR2-mediated chemotaxis of potentially damaging inflammatory cells. METHODS AND RESULTS: After ischemia-reperfusion in vivo, CXCR2-/- mice exhibited infarcts that were 50.5% smaller (P<0.05) with 44.3% fewer inflammatory cells (P<0.05) than wild type mice. These data suggest that in this model, CXCR2-mediated chemotaxis may be important in myocardial cell death. To isolate the role of CXCR2 specifically on blood cells, adoptive transfer experiments were performed. After ischemia-reperfusion, infarcts were 53.4% smaller (P<0.05) and contained 65.0% fewer inflammatory cells (P<0.05) in lethally irradiated wild type mice reconstituted with CXCR2-/- compared with wild type bone marrow. Thus, CXCR2 on blood cells is important in myocardial damage, most likely because of CXCR2-mediated chemotaxis. To unmask whether CXCR2 mediates direct myocardial protection in the intact heart, wild type and CXCR2-/- hearts were studied in the absence of blood using Langendorff preparations. In this case, infarcts were 19.7% larger in CXCR2-/- than wild type hearts (P<0.05), revealing a novel CXCR2-mediated cardioprotective effect. CONCLUSIONS: CXCR2 exerts opposing effects on myocardial viability during ischemia-reperfusion with recruitment of damaging inflammatory cells predominant over direct tissue protection.
Assuntos
Quimiotaxia de Leucócito/fisiologia , Isquemia Miocárdica/patologia , Traumatismo por Reperfusão Miocárdica/patologia , Receptores de Interleucina-8B/fisiologia , Transferência Adotiva , Animais , Células da Medula Óssea/metabolismo , Transplante de Medula Óssea , Morte Celular , Hipóxia Celular , Inflamação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Infarto do Miocárdio/imunologia , Infarto do Miocárdio/patologia , Isquemia Miocárdica/imunologia , Traumatismo por Reperfusão Miocárdica/imunologia , Neutrófilos/efeitos dos fármacos , Neutrófilos/fisiologia , Especificidade de Órgãos , Quimera por RadiaçãoRESUMO
Heart failure is a common, lethal condition whose pathogenesis is poorly understood. Recent studies have identified low levels of myocyte apoptosis (80-250 myocytes per 10(5) nuclei) in failing human hearts. It remains unclear, however, whether this cell death is a coincidental finding, a protective process, or a causal component in pathogenesis. Using transgenic mice that express a conditionally active caspase exclusively in the myocardium, we demonstrate that very low levels of myocyte apoptosis (23 myocytes per 10(5) nuclei, compared with 1.5 myocytes per 10(5) nuclei in controls) are sufficient to cause a lethal, dilated cardiomyopathy. Interestingly, these levels are four- to tenfold lower than those observed in failing human hearts. Conversely, inhibition of cardiac myocyte death in this murine model largely prevents the development of cardiac dilation and contractile dysfunction, the hallmarks of heart failure. To our knowledge, these data provide the first direct evidence that myocyte apoptosis may be a causal mechanism of heart failure, and they suggest that inhibition of this cell death process may constitute the basis for novel therapies.
Assuntos
Apoptose , Modelos Animais de Doenças , Insuficiência Cardíaca/etiologia , Miócitos Cardíacos/metabolismo , Tacrolimo/análogos & derivados , Animais , Caspase 8 , Caspase 9 , Caspases/genética , Dimerização , Progressão da Doença , Ativação Enzimática/efeitos dos fármacos , Ativadores de Enzimas/farmacologia , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/patologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/patologia , Especificidade de Órgãos/genética , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/efeitos dos fármacos , Proteínas Recombinantes de Fusão/genética , Tacrolimo/farmacologia , Proteínas de Ligação a Tacrolimo/genética , TransgenesRESUMO
Chemokines are small molecular weight proteins that play important roles in inflammation. Originally described as chemotactic cytokines, chemokines stimulate the influx of leukocytes into specific tissue compartments. These molecules also modulate gene expression in both infiltrating and resident cells to mediate a vast array of cellular functions, and their importance in disease processes has been well documented. This study examined the expression of chemokines during myocardial ischemia and established a pathway by which two, MIP-2 and JE/MCP-1, modulate cardiac myocyte viability during this process. To focus on the direct effects of chemokines on these cells, a mouse model of ischemia without reperfusion was used. The expression of chemokines and chemokine receptors was induced in the left ventricular free wall as early as 1 h post-ischemia, with the most significant increases in MIP-2 (CXCL2) and JE/MCP-1 (CCL2). Expression of their respective receptors, CXCR2 and CCR2, was also induced. Similar changes in gene expression occurred at the mRNA and protein levels in isolated neonatal mouse cardiac myocytes stimulated by hypoxia. Antibody to MIP-2 inhibited hypoxia-induced JE/MCP-1 expression, demonstrating that MIP-2 is critical for this event. Moreover, in vivo intramyocardial injection of either an adenovirus expressing MIP-2 or the recombinant protein itself was sufficient to upregulate JE/MCP-1 production even in the absence of ischemia. Thus, MIP-2 regulates JE/MCP-1 expression both in cell culture and in vivo. Furthermore, JE/MCP-1 markedly decreased hypoxia-induced cell death in cultured cardiac myocytes. Thus, JE/MCP-1 appears to mediate an unanticipated survival pathway in target cardiac myocytes themselves. These findings indicate an important role for MIP-2 and JE/MCP-1 in regulating the response of cardiac myocytes to myocardial ischemia.