Prostaglandin inhibition and myocardial infarct size

Systemic investigation of di-isobutyl phthalate (DIBP) exposure in the risk of cardiovascular via influencing the gut microbiota arachidonic acid metabolism in obese mice model

Phthalate esters (PE), a significant class of organic compounds used in industry, can contaminate humans and animals by entering water and food chains. Recent studies demonstrate the influence of PE on the development and progression of heart diseases, particularly in obese people. Di-isobutyl phthalate (DIBP) was administered orally to normal and diet-induced obese mice in this research to assess cardiovascular risk. The modifications in the microbial composition and metabolites were examined using RNA sequencing and mass spectrometry analysis. Based on the findings, lean group rodents were less susceptible to DIBP exposure than fat mice because of their cardiovascular systems. Histopathology examinations of mice fed a high-fat diet revealed lesions and plagues that suggested a cardiovascular risk. In the chronic DIBP microbial remodeling metagenomics Faecalibaculum rodentium was the predominant genera in obese mice. According to metabolomics data, arachidonic acid (AA) metabolism changes caused by DIBP were linked to unfavorable cardiovascular events. Our research offers new understandings of the cardiovascular damage caused by DIBP exposure in obese people and raises the possibility that arachidonic acid metabolism could be used as a regulator of the gut microbiota to avert related diseases.

NSAIDs and Cardiovascular Diseases: Role of Reactive Oxygen Species

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most commonly used drugs worldwide. NSAIDs are used for a variety of conditions including pain, rheumatoid arthritis, and musculoskeletal disorders. The beneficial effects of NSAIDs in reducing or relieving pain are well established, and other benefits such as reducing inflammation and anticancer effects are also documented. The undesirable side effects of NSAIDs include ulcers, internal bleeding, kidney failure, and increased risk of heart attack and stroke. Some of these side effects may be due to the oxidative stress induced by NSAIDs in different tissues. NSAIDs have been shown to induce reactive oxygen species (ROS) in different cell types including cardiac and cardiovascular related cells. Increases in ROS result in increased levels of oxidized proteins which alters key intracellular signaling pathways. One of these key pathways is apoptosis which causes cell death when significantly activated. This review discusses the relationship between NSAIDs and cardiovascular diseases (CVD) and the role of NSAID-induced ROS in CVD.

Nonsteroidal antiinflammatory drugs after acute myocardial infarction

BACKGROUND

Many older patients undergo therapy with nonsteroidal antiinflammatory drugs (NSAIDs), medications that produce effects on platelets and inflammation similar to those produced with aspirin. The impact of these agents on mortality after acute myocardial infarction is not known. We sought to determine whether the use of NSAIDs alone, or in addition to aspirin, is associated with a lower 1-year mortality rate in elderly patients after acute myocardial infarction.

METHODS

We performed an analysis of the Cooperative Cardiovascular Project, a retrospective medical record review that included demographic and clinical information for Medicare beneficiaries hospitalized with a diagnosis of acute myocardial infarction during 1994 and 1995. The cohort included 48,584 elderly patients with acute myocardial infarction without contraindications to NSAID or aspirin therapy. There were 736 patients (1.5%) who were prescribed NSAIDs alone, 36,211 (74.5%) prescribed aspirin alone, 2096 (4.3%) prescribed both NSAIDs and aspirin, and 9541 (19.6%) prescribed neither medication at discharge.

RESULTS

Compared with patients discharged with neither medication, prescriptions of NSAID therapy alone (hazard ratio [HR], 0.77; 95% CI, 0.65-0.90), aspirin alone (HR, 0.81; 95% CI, 0.77-0.86), and both medications (HR, 0.78; 95% CI, 0.69-0.88) were associated with lower adjusted 1-year mortality rates. Compared with patients prescribed NSAID therapy at discharge, there was no significant benefit associated with the addition of aspirin, and the benefit of NSAID therapy was not significantly different from that of aspirin alone.

CONCLUSION

The prescription of NSAID therapy at hospital discharge for elderly Medicare beneficiaries who survived acute myocardial infarction was associated with similarly lower 1-year mortality rates as compared with aspirin therapy. The addition of aspirin to NSAID therapy was not associated with an additional survival benefit.

Mechanisms of protection afforded by cyclooxygenase inhibitors to endothelial function against ischemic injury in rat isolated hearts

The aim of this study was to assess whether cyclooxygenase (COX) inhibitors protect the endothelial function against the deleterious effect of ischemia and reperfusion. Isolated rat hearts perfused under constant-flow conditions were exposed to 30 min of partial ischemia (flow, 1 ml/min) followed by 20 min of reperfusion, after which coronaries were precontracted with U-46619, and the response to the endothelium-dependent vasodilator, serotonin (5-HT), was compared with that of the endothelium-independent vasodilator, sodium nitroprusside (SNP). In untreated hearts, ischemia diminished selectively 5-HT-induced vasodilation, compared with sham hearts (without ischemia). The vasodilation to SNP was unaffected in all groups. Pretreatment with 6-MNA, 30 microM, a COX-2 inhibitor with some activity on COX 1, diclofenac, 1 microM (COX-1 and -2), or 1-(7-carboxyheptyl) imidazole, 10 microM [thromboxane (TX) synthase inhibitor] but not indomethacin, 10 microM (COX-1 inhibitor) preserved the vasodilation induced by 5-HT after ischemia. Enzyme immunoassays indicated that all COX inhibitors decreased the concentration of TXB2 and 6-keto-PGF1alpha [stable metabolites of TXA2 and prostacyclin (PGI2), respectively] in coronary effluent during ischemia. Furthermore, indomethacin was the only one to abolish the concentration of PGE2 during ischemia and early reperfusion. No clear trend on ventricular postischemic recovery could be observed between treated and untreated groups under our experimental protocols. These data suggest that, under our conditions, 6-MNA, diclofenac, and 1-7-CHI, but not indomethacin, protect the endothelial function via a reduction in TX concentration. Disparities between COX inhibitors may be due to the complete abolition of PGE2 concentration during ischemia and reperfusion in the indomethacin group.

Delayed effects of early infarct-limiting therapies on healing after myocardial infarction

The effect of early infarct-limiting therapy on the hydroxypyroline (OHP, a marker of collagen) content and topography of 7-day-old infarcts was studied in 76 conscious dogs (69 ligated; seven sham operated). Two hours after their left anterior descending coronary arteries were occluded, 69 dogs were randomly assigned to receive 6 hr intravenous infusions of saline (controls; n = 29), low-dose nitroglycerin (NG; n = 13), prostacyclin (PGI2; n = 14), or ibuprofen (IBU; n = 13). Regional OHP (mg/g dry weight) was measured by spectrophotometry, and size of infarction and topography were determined by computerized planimetry. Infarct size was less in the NG, PGI2, and IBU groups compared with that in the saline group, both when measured as a percent of the arteriographic occluded bed (p less than .001) and as a percent of the left ventricle (p less than .005). For each treatment group (1) the level of OHP was higher (p less than .001) in the region of infarction (saline group, 9.9 +/- 0.7 mg/g; NG group, 14.9 +/- 1.9 mg/g; PGI2 group, 12.9 +/- 0.9 mg/g; IBU group, 10.6 +/- 1.4 mg/g) than in normal zones (4.4 +/- 0.2 mg/g), with more (p less than .05) OHP in border than center regions, and (2) the total OHP in the infarct zone was linearly related to size of infarction as a percent of the left ventricle (r = .89 to .94). However, the slopes of regressions for the NG, PGI2, and IBU groups were greater (p less than .001) than the slope for the saline group.(ABSTRACT TRUNCATED AT 250 WORDS)

Failure of percutaneous transluminal coronary angioplasty to stimulate platelet and prostaglandin activity

Platelet function and prostaglandin activity were evaluated in nine patients with coronary artery disease undergoing percutaneous left anterior descending coronary artery angioplasty (PTCA) and compared to nine normal controls. Transcoronary measurements (arterial-coronary sinus) of platelet counts, mean platelet volume, platelet factor 4 (PF4), beta thromboglobulin, thromboxane (B2), and 6-keto-PGF 1 alpha were made. When compared to normal controls, the patients with coronary artery disease had higher circulating baseline levels of PF4 in the coronary sinus. There was no transcardiac production of any factor at baseline or immediately after infusion of nitroglycerin or performance of PTCA. These results suggest that PTCA does not grossly alter arachidonic acid metabolism or platelet activity.

Effect of prostacyclin infusion during low-flow ischaemia in the isolated perfused rat heart

Although prostacyclin (PGI2) has been shown to exert a protective effect on ischaemic hearts its precise mode of action remains obscure. Possible explanations include protection of the high energy phosphate stores (ATP and CP), maintenance of homeostasis with respect to Ca2+, and an antiaggregatory effect. The following experiments were undertaken to investigate these possibilities, using isolated, spontaneously beating rat hearts perfused with Krebs-Henseleit solution. Ischaemia was induced at 37 degrees C for 30 min by reducing the flow rate from 10.0 to 0.1 ml/min, and was followed by reperfusion. PGI2 was given as a constant infusion (20 ng/ml). The hearts were frozen and assayed for ATP and CP, or digested in HNO3 and assayed for Ca2+. Peak developed tension was recorded throughout. The results show that PGI2 slowed the rate of decline of developed tension during low flow perfusion, and hastened the recovery of contractions on reperfusion. These effects could not be accounted for in terms of an improved supply of ATP or CP, or an altered tissue Ca2+. The protective effect of PGI2 on isolated, buffer-perfused hearts may be a reflection of a generalized, but undefined, mechanism of cell preservation which has also been observed in other systems.

Prostaglandins in myocardial: with emphasis on myocardial preservation

Various therapies during early hours of acute myocardial infarction (AMI) have been suggested to protect ischemic myocardium and reduce infarct size. Despite reports that prostaglandins (PGs) are released during myocardial ischemia, and that prostacyclin (PGI2) and thromboxane A2 (TXA2) have opposing effects on vasomotion and platelet aggregation, the physiologic roles of PGs, PGI2 and TXA2 in AMI have not been clearly defined. However, in pharmacologic doses, experimental evidence suggests that vasodilator PGs might be beneficial, and vasoconstrictor PGs might be deleterious, in AMI. Recent recognition that coronary spasm is frequent in AMI has led to the notion that an increased PGI2/TXA2 ratio might be desirable. Thus, exogenous PGE1, exogenous PGI2 or tis more stable analogs, drugs that stimulate PGI2 release, and inhibitors of TXA2 and harmful PGs are potential agents for protective therapy in AMI.