Cardioprotective actions of thromboxane receptor antagonism in ischemic atherosclerotic rabbits

1988 ◽  
Vol 255 (2) ◽  
pp. H318-H324 ◽  
Author(s):  
J. A. Osborne ◽  
A. M. Lefer
Keyword(s):  
Myocardial Ischemia ◽  
Plasma Cholesterol ◽  
Amino Nitrogen ◽  
Oxygen Demand ◽  
Myocardial Oxygen Demand ◽  
Sham Operation ◽  
Protective Effects ◽  
Beneficial Effects ◽  
Antiatherogenic Effect ◽  
Nitrogen Containing Compounds

Atherosclerosis was induced in New Zealand White rabbits by feeding them a 0.5% cholesterol-enriched rabbit chow for 10–12 wk. Half of the cholesterol-fed rabbits were given BM 13505, a specific thromboxane A2/endoperoxide (TxA2/PGH2) receptor antagonist, and the other half were given its vehicle (i.e., 2% Na2CO3). At the end of 10–12 wk, the rabbits underwent experimental myocardial ischemia or an identical sham operation, except that the coronary artery was not occluded. BM 13505 was shown to protect the ischemic rabbit myocardium by three different methods: 1) maintenance of myocardial tissue creatine kinase (CK) activity in the ischemic myocardium; 2) reduced loss of free amino nitrogen-containing compounds from the myocardium; and 3) blunting the rise of plasma CK activity. Part of the mechanism for these effects may be due to inhibition of platelet aggregation and blockade of the vasoconstrictor effect of TxA2. However, these protective effects were not due to differences in myocardial oxygen demand among the groups. Finally, BM 13505 exhibited an antiatherogenic effect by reducing the deposition of cholesterol in the aortic wall and by retarding plaque formation in coronary arteries. However, it does not achieve this antiatherogenic effect by lowering plasma cholesterol concentrations or by scavenging superoxide free radicals. Thus blockade of TxA2 receptors exerts a variety of beneficial effects that reduce the severity of ischemic damage resulting from myocardial ischemia.

Beneficial effects of SPM-5185, a cysteine-containing NO donor in myocardial ischemia-reperfusion

1992 ◽  
Vol 263 (3) ◽  
pp. H771-H777 ◽  
Author(s):  
M. R. Siegfried ◽  
C. Carey ◽  
X. L. Ma ◽  
A. M. Lefer
Keyword(s):  
At Risk ◽  
Endothelial Dysfunction ◽  
Myocardial Ischemia ◽  
Ethyl Ester ◽  
Ischemia Reperfusion ◽  
Myocardial Oxygen Demand ◽  
Area At Risk ◽  
No Donor ◽  
Beneficial Effects ◽  
Myocardial Ischemia Reperfusion

Intravenous administration of SPM-5185 [N-nitratopivaloyl-S-(N–-acetylalanyl)-cysteine ethyl ester], a cysteine-containing nitric oxide (NO) donor, or SPM-5267 [pivaloyl-S-(N–-acetylalanyl)-cysteine ethyl ester], an analogue of SPM-5185 that lacks the NO moiety, was studied in a feline myocardial ischemia-reperfusion model. Administration of SPM-5185 (1 mg/kg), followed by a 2-mg.kg-1.h-1 infusion starting 10 min before reperfusion, resulted in significant protection 4.5 h postreperfusion. In the myocardial ischemia (MI)+SPM-5267 group, 38 +/- 4% of the area at risk was necrotic, whereas the necrotic area/area at risk was only 7 +/- 2% in the MI+SPM-5185 group (P less than 0.01). Moreover, SPM-5185 treatment markedly attenuated the endothelial dysfunction observed in the left anterior descending coronary artery after reperfusion by 50%. These beneficial effects occurred despite the absence of a significant change in myocardial oxygen demand, as measured by the pressure-rate index. In vitro experiments demonstrated that SMP-5185, but not SPM-5267, decreased adherence of neutrophils to the coronary vascular endothelium and decreased production of superoxide radicals. Therefore, a likely mechanism of the observed cardioprotection by SPM-5185 involves attenuation of polymorphonuclear leukocyte-induced endothelial dysfunction.

scholarly journals Repetitive Myocardial Infarctions Secondary to Delirium Tremens

2014 ◽  
Vol 2014 ◽  
pp. 1-3
Author(s):  
David Schwartzberg ◽  
Adam Shiroff
Keyword(s):  
Myocardial Infarction ◽  
Myocardial Ischemia ◽  
Alcohol Withdrawal ◽  
Delirium Tremens ◽  
Oxygen Demand ◽  
Myocardial Infarctions ◽  
Myocardial Oxygen Demand ◽  
Significant Morbidity ◽  
St Segment ◽  
Patients Experience

Delirium tremens develops in a minority of patients undergoing acute alcohol withdrawal; however, that minority is vulnerable to significant morbidity and mortality. Historically, benzodiazepines are given intravenously to control withdrawal symptoms, although occasionally a more substantial medication is needed to prevent the devastating effects of delirium tremens, that is, propofol. We report a trauma patient who required propofol sedation for delirium tremens that was refractory to benzodiazepine treatment. Extubed prematurely, he suffered a non-ST segment myocardial infarction followed by an ST segment myocardial infarction requiring multiple interventions by cardiology. We hypothesize that his myocardial ischemia was secondary to an increased myocardial oxygen demand that occurred during his stress-induced catecholamine surge during the time he was undertreated for delirium tremens. This advocates for the use of propofol for refractory benzodiazepine treatment of delirium tremens and adds to the literature on the instability patients experience during withdrawal.

Effects of atrial pacing on regional myocardial gas tensions with critical coronary stenosis

1977 ◽  
Vol 232 (1) ◽  
pp. H49-H53 ◽  
Author(s):  
J. B. O'Riordan ◽  
J. T. Flaherty ◽  
S. F. Khuri ◽  
R. K. Brawley ◽  
B. Pitt ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Blood Flow ◽  
Myocardial Ischemia ◽  
Coronary Stenosis ◽  
Oxygen Demand ◽  
Myocardial Oxygen Demand ◽  
Atrial Pacing ◽  
Myocardial Layers ◽  
Regional Myocardial Ischemia ◽  
Stenosed Vessel

Changes in myocardial carbon dioxide (PmCO2) and oxygen tension (PmO2) measured by mass spectrometry have been shown to reflect quantitatively progressive degrees of regional myocardial ischemia associated with stepwise reduction in coronary blood flow. The present study utilized mass spectrometry to assess the severity of regional myocardial ischemia developing during atrial pacing in the presence of a flow-limiting proximal critical coronary artend subendocardial layers was measured by the radioactive microsphere technique. Application of a “critical stenosis” resulted in a 6-mmHg decrease in PmO2 and a 17-mmHg increase in PmCO2 in the region of the myocardium supplied by the stenosed vessel. The addition of atrial pacing resulted in a 3-mmHg further decrease in Pmo2 and a 40-mmHg further increase in PmCO2. In the region of myocardium supplied by the critically stenosed vessel MBF increased in the subepicardial layer, but decreased or remained unchanged in the subendocardial layer. The failure of myocardial blood flow to increase in deeper myocardial layers in response to the increased myocardial oxygen demand of atrial pacing would provide a mechanism for the development of subendocardial ischemia in the presence of a critical coronary stenosis.

scholarly journals Myocardial ischemia during daily activities: The importance of increased myocardial oxygen demand

1991 ◽  
Vol 18 (2) ◽  
pp. 405-412 ◽  
Author(s):  
Alan Hinderliter ◽  
Paula Miller ◽  
Edith Bragdon ◽  
Martha Ballenger ◽  
David Sheps
Keyword(s):  
Myocardial Ischemia ◽  
Oxygen Demand ◽  
Daily Activities ◽  
Myocardial Oxygen Demand

Protective effects of miR-34b and miR-337 against myocardial ischemia/reperfusion injury in rats by liposomal nano-delivery system

2021 ◽  
Vol 11 (7) ◽  
pp. 1147-1153
Author(s):  
Junyan Liu ◽  
Jingxian Xing ◽  
Ya Li ◽  
Juan Liu ◽  
Miao Tian ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Reperfusion Injury ◽  
Rat Model ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Sham Operation ◽  
Protective Effects ◽  
Expression Levels ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Although a few microRNAs (miRNAs) are involved in the regulation of myocardial ischemia/reperfusion injury (MI/RI), their exact roles in this process, and the mechanisms involved have not been fully elucidated. This study was carried out to investigate the protective effects of miR-34b and miR-337 against MI/RI. For this purpose, 56 Sprague-Dawley (SD) rats were randomly divided into two groups: sham operation group and myocardial MI/RI group, with 28 rats in each group. Then, a rat model of MI/RI was established. Changes in myocardial tissues of the two groups were determined using hematoxylin-Eosin (H&E) staining. Serum level of myocardial troponin c(TnT) was assayed with ELISA method, while myocardial tissue mRNA expressions of miR in the two groups was determined with qRT-PCR. Results showed that the rat model of MI/RI was successfully established, as was evident in myocardial cell necrosis, disorganized myocardial fibers, interstitial edema, and neutrophil infiltration. There were significant increases in serum troponin content and mRNA expression levels of miR-337 and miR-34b in tissues. In conclusion, the expression levels of miR-337 and miR-34b are increased in myocardial tissues of rats with MI/RI. Thus, miR-337 and miR-34b may be involved in the pathogenesis of MI/RI via regulation of NOX4 and Samd7, respectively. Finally, by using liposomal nanocarrier, the therapeutic effect of miR-337 and miR-34b on MI/RI was investigated.

Role of Heart Rate Reduction in the Management of Myocarditis

2018 ◽  
Vol 24 (3) ◽  
pp. 365-378 ◽  
Author(s):  
Chen Guang-Yi ◽  
Ge Li-Sha ◽  
Li Yue-Chun
Keyword(s):  
Heart Rate ◽  
Nitrosative Stress ◽  
Ventricular Remodeling ◽  
Animal Experiments ◽  
Viral Myocarditis ◽  
Protective Effects ◽  
Heart Rate Reduction ◽  
Rate Reduction ◽  
Beneficial Effects ◽  
Biological Technique

The morbidity of myocarditis demonstrates an upward tendency by years, is commonly defined as the inflammation of myocytes and is caused by multiple factors. With the development of the molecular biological technique, great breakthroughs in the diagnosis and understanding of pathophysiological mechanisms of myocarditis have recently been achieved. Several questions remain unresolved, however, including standard treatment approaches to myocarditis, which remain controversial and ambiguous. Heart rate, as an independent risk factor, has been shown to be related to cardiac disease. Recent studies also show that the autonomic nervous system is involved in immunomodulatory myocarditis processes. Heart rate reduction treatment is recommended in myocarditis based on a number of animal experiments and clinical trials. It is possible that heart rate-lowering treatments can help to attenuate the inflammatory response and myocyte injury and reverse ventricular remodeling. However, how to execute the protective effects of heart rate reduction on myocarditis is still not clear. In this review, we discuss the pathogenesis and pathophysiological process of viral myocarditis and propose heart rate lowering as a therapeutic target for myocarditis, especially in light of the third-generation β-blockade carvedilol and funny channel blocker ivabradine. We also highlight some additional beneficial effects of such heart rate reduction agents, including anti-inflammatory, antioxidation, anti-nitrosative stress, anti-fibrosis and antiapoptosis properties.

scholarly journals Strawberry and Achenes Hydroalcoholic Extracts and Their Digested Fractions Efficiently Counteract the AAPH-Induced Oxidative Damage in HepG2 Cells

2018 ◽  
Vol 19 (8) ◽  
pp. 2180 ◽  
Author(s):  
María Ariza ◽  
Tamara Forbes-Hernández ◽  
Patricia Reboredo-Rodríguez ◽  
Sadia Afrin ◽  
Massimiliano Gasparrini ◽  
...  
Keyword(s):  
Biological Activity ◽  
Oxidative Damage ◽  
Hepg2 Cells ◽  
In Vitro Digestion ◽  
Protective Effects ◽  
Beneficial Effects ◽  
Positive Effects ◽  
Digestion Process ◽  
Phytochemical Compounds

Strawberry fruits are highly appreciated by consumers worldwide due to their bright red color, typical aroma, and juicy texture. While the biological activity of the complete fruit has been widely studied, the potential beneficial effects of the achenes (commonly named seeds) remain unknown. In addition, when raw fruit and achenes are consumed, the digestion process could alter the release and absorption of their phytochemical compounds, compromising their bioactivity. In the present work, we evaluated the protective effects against oxidative damage of nondigested and digested extracts from strawberry fruit and achenes in human hepatocellular carcinoma (HepG2) cells. For that purpose, cells were treated with different concentration of the extracts prior to incubation with the stressor agent, AAPH (2,2′-azobis(2-amidinopropane) dihydrochloride). Subsequently, intracellular accumulation of reactive oxygen species (ROS) and the percentage of live, dead, and apoptotic cells were determined. Our results demonstrated that all the evaluated fractions were able to counteract the AAPH-induced damage, suggesting that the achenes also present biological activity. The positive effects of both the raw fruit and achenes were maintained after the in vitro digestion process.

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