Interaction between cyclooxygenase and the renin-angiotensin-aldosterone system: rationale and clinical relevance

Impaired immune response mediated by prostaglandin E2 promotes severe COVID-19 disease

The SARS-CoV-2 coronavirus has led to a pandemic with millions of people affected. The present study finds that risk-factors for severe COVID-19 disease courses, i.e. male sex, older age and sedentary life style are associated with higher prostaglandin E2 (PGE2) serum levels in blood samples from unaffected subjects. In COVID-19 patients, PGE2 blood levels are markedly elevated and correlate positively with disease severity. SARS-CoV-2 induces PGE2 generation and secretion in infected lung epithelial cells by upregulating cyclo-oxygenase (COX)-2 and reducing the PG-degrading enzyme 15-hydroxyprostaglandin-dehydrogenase. Also living human precision cut lung slices (PCLS) infected with SARS-CoV-2 display upregulated COX-2. Regular exercise in aged individuals lowers PGE2 serum levels, which leads to increased Paired-Box-Protein-Pax-5 (PAX5) expression, a master regulator of B-cell survival, proliferation and differentiation also towards long lived memory B-cells, in human pre-B-cell lines. Moreover, PGE2 levels in serum of COVID-19 patients lowers the expression of PAX5 in human pre-B-cell lines. The PGE2 inhibitor Taxifolin reduces SARS-CoV-2-induced PGE2 production. In conclusion, SARS-CoV-2, male sex, old age, and sedentary life style increase PGE2 levels, which may reduce the early anti-viral defense as well as the development of immunity promoting severe disease courses and multiple infections. Regular exercise and Taxifolin treatment may reduce these risks and prevent severe disease courses.

The effect of diclofenac sodium intoxication on the cardiovascular system in rats

OBJECTIVES

Diclofenac sodium (DS) is a widely used nonsteroidal anti-inflammatory drug. Although its high doses are known to cause toxic effects in many tissues including liver and kidney, the effects on the cardiovascular system (CVS) have not been fully elucidated yet. Therefore, this study aimed to investigate the effect of DS on CVS.

METHODS

The Control group did not receive medication; however, a single dose of 240 mg/kg DS was administered orally to the DS group. Electrocardiography (ECG) measurements were performed in all animals before (0thhour) and after (1st,6th,12th,24thhour) intoxication. After 24 h, All animals were sacrificed. Biochemical (malondialdehyde [MDA], and glutathione (GSH), Apelin, Elabela, Meteorin, Endoglin, Keap1, and Nrf2) and histopathological analyzes were performed on heart tissue samples.

RESULTS

ECG results showed that there was a statistically significant increase in QTc, QRS, and heart rate at the 12th and 24th hours in the DS group. The biochemical analysis showed that GSH, Apelin, Keap1, and NRF2 values decreased significantly while Meteorin and Endoglin levels increased in the DS group. When histopathological results were evaluated, distinct lesions were observed in the DS group.

CONCLUSION

In conclusion, high doses of DS intake can cause adverse effects on and damage to CVS.

Repurposing existing drugs for COVID-19: an endocrinology perspective

BACKGROUND

Coronavirus Disease 2019 (COVID-19) is a multi-systemic infection caused by the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), that has become a pandemic. Although its prevailing symptoms include anosmia, ageusia, dry couch, fever, shortness of brief, arthralgia, myalgia, and fatigue, regional and methodological assessments vary, leading to heterogeneous clinical descriptions of COVID-19. Aging, uncontrolled diabetes, hypertension, obesity, and exposure to androgens have been correlated with worse prognosis in COVID-19. Abnormalities in the renin-angiotensin-aldosterone system (RAAS), angiotensin-converting enzyme-2 (ACE2) and the androgen-driven transmembrane serine protease 2 (TMPRSS2) have been elicited as key modulators of SARS-CoV-2.

MAIN TEXT

While safe and effective therapies for COVID-19 lack, the current moment of pandemic urges for therapeutic options. Existing drugs should be preferred over novel ones for clinical testing due to four inherent characteristics: 1. Well-established long-term safety profile, known risks and contraindications; 2. More accurate predictions of clinical effects; 3. Familiarity of clinical management; and 4. Affordable costs for public health systems. In the context of the key modulators of SARS-CoV-2 infectivity, endocrine targets have become central as candidates for COVID-19. The only endocrine or endocrine-related drug class with already existing emerging evidence for COVID-19 is the glucocorticoids, particularly for the use of dexamethasone for severely affected patients. Other drugs that are more likely to present clinical effects despite the lack of specific evidence for COVID-19 include anti-androgens (spironolactone, eplerenone, finasteride and dutasteride), statins, N-acetyl cysteine (NAC), ACE inhibitors (ACEi), angiotensin receptor blockers (ARB), and direct TMPRSS-2 inhibitors (nafamostat and camostat). Several other candidates show less consistent plausibility. In common, except for dexamethasone, all candidates have no evidence for COVID-19, and clinical trials are needed.

CONCLUSION

While dexamethasone may reduce mortality in severely ill patients with COVID-19, in the absence of evidence of any specific drug for mild-to-moderate COVID-19, researchers should consider testing existing drugs due to their favorable safety, familiarity, and cost profile. However, except for dexamethasone in severe COVID-19, drug treatments for COVID-19 patients must be restricted to clinical research studies until efficacy has been extensively proven, with favorable outcomes in terms of reduction in hospitalization, mechanical ventilation, and death.

Non-steroidal anti-inflammatory drug (NSAID) therapy in patients with hypertension, cardiovascular, renal or gastrointestinal comorbidities: joint APAGE/APLAR/APSDE/APSH/APSN/PoA recommendations

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly prescribed medications, but they are associated with a number of serious adverse effects, including hypertension, cardiovascular disease, kidney injury and GI complications.

OBJECTIVE

To develop a set of multidisciplinary recommendations for the safe prescription of NSAIDs.

METHODS

Randomised control trials and observational studies published before January 2018 were reviewed, with 329 papers included for the synthesis of evidence-based recommendations.

RESULTS

Whenever possible, a NSAID should be avoided in patients with treatment-resistant hypertension, high risk of cardiovascular disease and severe chronic kidney disease (CKD). Before treatment with a NSAID is started, blood pressure should be measured, unrecognised CKD should be screened in high risk cases, and unexplained iron-deficiency anaemia should be investigated. For patients with high cardiovascular risk, and if NSAID treatment cannot be avoided, naproxen or celecoxib are preferred. For patients with a moderate risk of peptic ulcer disease, monotherapy with a non-selective NSAID plus a proton pump inhibitor (PPI), or a selective cyclo-oxygenase-2 (COX-2) inhibitor should be used; for those with a high risk of peptic ulcer disease, a selective COX-2 inhibitor plus PPI are needed. For patients with pre-existing hypertension receiving renin-angiotensin system blockers, empirical addition (or increase in the dose) of an antihypertensive agent of a different class should be considered. Blood pressure and renal function should be monitored in most cases.

CONCLUSION

NSAIDs are a valuable armamentarium in clinical medicine, but appropriate recognition of high-risk cases, selection of a specific agent, choice of ulcer prophylaxis and monitoring after therapy are necessary to minimise the risk of adverse events.

Angiotensin II induces cyclooxygenase 2 expression in rat astrocytes via the angiotensin type 1 receptor

We previously showed that Angiotensin (Ang) II stimulated pro-inflammatory and mitogenic actions in astrocytes suggesting that astrocytes are emerging as key players in neuroinflammation. Evidence suggests that neuroinflammation may contribute to central sympathetic overactivity and elevated blood pressure. Further, cyclooxygenase (Cox)-derived prostanoids were implicated in Ang II-dependent hypertension. Cox2 is one of two Cox isoenzymes that is responsible for the formation of prostanoids from arachidonic acid. Constitutively expressed Cox2 has a protective and homeostatic role in the cardiovascular and renal systems. Inducible Cox2 has been associated with pathogenic stimuli resulting in inflammatory conditions and cancers. In this study, we investigated the effect of Ang II on Cox2 protein and mRNA expression in brainstem and cerebellum astrocytes, and determined whether any differences in Cox2 expression exist in spontaneously hypertensive rat (SHR) astrocytes compared to their normotensive control Wistar rats. We demonstrated that Ang II increased Cox2 protein and mRNA levels relative to untreated controls in a time-dependent manner, in Wistar and SHR brainstem and cerebellum astrocytes. Increases in Cox2 protein expression were evident within 4 h, with subsequent sustained elevation for several hours followed by a decline at 48 h. Ang II-induced Cox2 protein levels were higher in Wistar compared to SHRs in both brainstem and cerebellum astrocytes for the majority of time points examined. The Ang II-induced Cox2 mRNA levels increased within 8 h followed by a rapid decline to almost basal levels at later time points. At the earlier time points, Cox2 mRNA elevation were higher in SHR compared to Wistar rat astrocytes. These Ang II actions were mediated by the Ang type I receptor. Our results corroborate previous reports of Ang II's ability to stimulate neuroinflammatory mediators in astrocytes. Cox2-derived prostaglandins might play a role in brain-renin angiotensin system associated hypertension, and astrocytes could be significant players.

Definition of hidden drug cardiotoxicity: paradigm change in cardiac safety testing and its clinical implications

Unexpected cardiac adverse effects are the leading causes of discontinuation of clinical trials and withdrawal of drugs from the market. Since the original observations in the mid-90s, it has been well established that cardiovascular risk factors and comorbidities (such as ageing, hyperlipidaemia, and diabetes) and their medications (e.g. nitrate tolerance, adenosine triphosphate-dependent potassium inhibitor antidiabetic drugs, statins, etc.) may interfere with cardiac ischaemic tolerance and endogenous cardioprotective signalling pathways. Indeed drugs may exert unwanted effects on the diseased and treated heart that is hidden in the healthy myocardium. Hidden cardiotoxic effects may be due to (i) drug-induced enhancement of deleterious signalling due to ischaemia/reperfusion injury and/or the presence of risk factors and/or (ii) inhibition of cardioprotective survival signalling pathways, both of which may lead to ischaemia-related cell death and/or pro-arrhythmic effects. This led to a novel concept of ‘hidden cardiotoxicity’, defined as cardiotoxity of a drug that manifests only in the diseased heart with e.g. ischaemia/reperfusion injury and/or in the presence of its major comorbidities. Little is known on the mechanism of hidden cardiotoxocity, moreover, hidden cardiotoxicity cannot be revealed by the routinely used non-clinical cardiac safety testing methods on healthy animals or tissues. Therefore, here, we emphasize the need for development of novel cardiac safety testing platform involving combined experimental models of cardiac diseases (especially myocardial ischaemia/reperfusion and ischaemic conditioning) in the presence and absence of major cardiovascular comorbidities and/or cotreatments.

A Review of Prognostic Tools in Heart Failure

A minority of patients with end-stage disease are referred to palliative medicine for consultation in advanced heart failure. Educating stakeholders, including primary care, cardiology, and critical care of the benefits of hospice and palliative medicine for patients with poor prognosis, may increase appropriately timed referrals and improve quality of life for these patients. This article reviews multiple tools useful in prognostication in the setting of advanced heart failure.

Effect of benazepril, robenacoxib and their combination on glomerular filtration rate in cats

Background

Combined use of angiotensin-converting enzyme inhibitors and nonsteroidal anti-inflammatory drugs may induce acute kidney injury in humans, especially when combined with diuretics. The objective of this investigation was to evaluate the effects of benazepril, robenacoxib and their combination in healthy cats.

In each of two studies (study 1 followed by study 2), 32 healthy cats were randomised to one of four groups (n = 4 male and 4 female cats per group) in a parallel-group design. The groups received orally once daily for 7 days either placebo (control group), benazepril, robenacoxib or benazepril plus robenacoxib. In study 2, all groups received in addition 0.5 mg/kg furosemide twice daily by subcutaneous injection for 7 days.

Results

Benazepril, robenacoxib and their combination were well tolerated as evidenced from lack of clinical signs and no negative effects on body weight, feed consumption and clinical chemistry, haematology and urinalysis variables.

The primary endpoint of the study was the glomerular filtration rate (GFR), which was estimated from the plasma clearance of iohexol. In the absence of furosemide, GFR was significantly higher in cats receiving the combination of benazepril plus robenacoxib compared to the other three groups, and was also significantly higher in females receiving only benazepril compared to the control.

Administration of furosemide induced diuresis, reduced GFR and activated the renin-aldosterone-angiotensin system, evidenced from increased plasma renin activity and plasma aldosterone concentrations. Compared to the control group in cats treated with furosemide, GFR was increased by benazepril (females only) but decreased by robenacoxib (males only). Benazepril, robenacoxib and their combination significantly inhibited the increase in plasma aldosterone induced by furosemide.

Conclusions

The combination of benazepril and robenacoxib was well tolerated and either increased or had a neutral effect on GFR in healthy cats without or with concomitant furosemide. The combination of benazepril and robenacoxib reduced plasma aldosterone concentrations increased by furosemide. It is recommended to test the efficacy and safety of the combined use of benazepril and robenacoxib in cats with clinical disease, notably proteinuric chronic kidney disease.

Effect of benazepril and robenacoxib and their combination on glomerular filtration rate in dogs

Combined use of angiotensin-converting enzyme inhibitors and nonsteroidal anti-inflammatory drugs may induce acute kidney injury, especially when combined with diuretics. The objective of this investigation was to evaluate the effect of benazepril, robenacoxib and their combination in healthy dogs. In each of two studies (studies 1 and 2), 32 beagle dogs were randomized into one of four groups in a parallel-group design. Groups received once-daily oral treatment for 7 days with placebo, benazepril, robenacoxib or benazepril plus robenacoxib. In study 2, all dogs received additionally 2 mg/kg furosemide orally twice daily. The primary endpoint was the glomerular filtration rate (GFR) estimated from the plasma clearance of iohexol. Secondary endpoints included standard clinical monitoring and, in study 2, plasma renin activity, urine volume, specific gravity and aldosterone concentration and water intake. Administration of furosemide induced diuresis, reduced GFR and activated the renin-aldosterone-angiotensin system. Benazepril and robenacoxib, administered alone or in combination, were tolerated well, did not decrease GFR with or without co-administration of furosemide and significantly reduced urinary aldosterone concentrations. No increased risk of acute kidney injury was identified with the combination of benazepril and robenacoxib in healthy dogs. Different effects might occur in dogs with heart or renal disease.

Does aspirin use adversely influence intermediate-term postdischarge outcomes for hospitalized patients who are treated with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers? Findings from Organized Program to Facilitate Life-Saving Treatment in Hospitalized Patients with Heart Failure (OPTIMIZE-HF)

BACKGROUND

Conflicting data exist regarding a potential deleterious association between aspirin (ASA) and angiotensin-converting enzyme inhibitors (ACEIs) when used concurrently in patients with heart failure (HF). How such an interaction may be influenced by underlying etiology of HF and whether it extends to patients treated with angiotensin receptor blockers (ARBs), however, are not known.

METHODS

Eligible patients from the OPTIMIZE-HF registry were dichotomized into those with ischemic or nonischemic HF. Potential associations between ASA and ACEI or ARB use and 60- to 90-day postdischarge outcomes were assessed using Cox proportional and logistic regression modeling. Models were adjusted for factors known to influence the outcome of interest and by propensity score for ACEI or ARB prescription after an index HF admission.

RESULTS

Mortality was not increased (hazard ratio [95% CI]) when ASA was used in conjunction with ACEI (0.51 [0.29-0.87]) or ARB (0.29 [0.09-0.96]) in patients with ischemic or nonischemic (ACEI 0.71 [0.42-1.21], ARB 1.42 [0.74-2.74]) HF. Regression model parameter estimates trended toward harm reduction, but interaction terms for mortality and a composite of mortality or rehospitalization were nonsignificant (P for all >.05).

CONCLUSIONS

When combined with ACEI or ARB, ASA had no demonstrable adverse effect on intermediate-term postdischarge outcomes for patients with ischemic or nonischemic HF.

High-density lipoprotein cholesterol levels and prognosis in advanced heart failure

BACKGROUND

High-density lipoproteins (HDLs) influence the generation of prostacyclin via cyclooxygenase stimulation. Prostaglandins represent an important compensatory pathway in advanced heart failure (HF). Whether HDL levels discriminate prognosis in HF remains unknown.

METHODS

We prospectively evaluated the prognostic relationship of HDL levels in severe HF by examining 132 consecutive patients listed for heart transplantation (52 +/- 11 years of age, 80% men, 79% white, mean follow-up 18 months). Using population mean HDL levels (HDL <33 mg/dl [n = 47] vs > or =33 mg/dl [n = 85]), patients were grouped and followed for the primary composite end-points of HF hospitalizations or death, stratified by underlying etiology (non-ischemic, n = 52; ischemic, n = 80).

RESULTS

Patients with HDL <33 mg/dl had lower serum sodium (135 vs 137 mEq/liter, p = 0.008), higher total bilirubin (1.3 vs 0.7 mg/dl, p < 0.001) and higher uric acid (7.6 vs 6.7 mg/dl, p = 0.048) levels, but similar serum creatinine compared with the > or =33 mg/dl HDL group. Survival analysis, using a Cox proportional hazards model, revealed reduced HDL (<33 mg/dl) as the most significant independent predictor of HF hospitalizations or death, independent of underlying etiology. Low-cholesterol and low-density lipoprotein (LDL)-cholesterol alone were not found to be independently predictive of outcome.

CONCLUSIONS

Lower HDL levels correlate with adverse prognosis independent of etiology and predict clinical worsening or death in advanced HF. Further study is warranted as to whether these findings represent a clinical marker or suggest a potential therapeutic target.

Osteoarthritis: An Update on Data Currently Reshaping Practice

Osteoarthritis is common, has considerable health consequences, and will affect increasing numbers of persons in coming years. Nonpharmacological interventions are of paramount importance in achieving adequate symptom control. Acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) play a pivotal role in osteoarthritis pharmacotherapy. Acetaminophen, due to its safety profile, should be adequately trialed before resorting to NSAIDs. NSAIDs and celecoxib, a selective inhibitor of cyclooxygenase-2, should be selected thoughtfully so as to balance the likelihood of treatment success with gastrointestinal bleeding and cardiovascular events. Celecoxib may be used when the risk for gastrointestinal bleeding is high and the risk of cardiovascular events low. Otherwise, NSAIDs, usually naproxen, should be paired with a gastroprotective agent. Topical NSAIDs, including a recently approved diclofenac patch and gel, may also be useful when systemic exposure is undesirable. The role of glucosamine and chondroitin is controversial and the data conflicting. Other modalities, such as tramadol, opioids, and viscosupplementation should be tailored to the patient and clinical situation. Appropriate deployment of agents in the osteoarthritis armamentarium can maximize efficacy and safety thereby improving the disease burden for patients.

Role of the renin-angiotensin system in vascular inflammation

Angiotensin (Ang) II, the main effector of the renin-angiotensin system (RAS), is one of the major mediators of vascular remodeling in hypertension. Besides being a potent vasoactive peptide, Ang II exerts proinflammatory effects on the vasculature by inducing integrins, adhesion molecules, cytokines and growth and profibrotic mediators through activation of redox-sensitive pathways and transcription factors. Clinical findings suggest that inflammation participates in the mechanisms involved in the pathophysiology of hypertension and its complications. Antagonists of the RAS have been shown to exert cardiovascular protection, in part through their vascular anti-inflammatory effects. However, further studies are needed to better understand whether inflammatory biomarkers might be clinically useful for cardiovascular risk stratification and whether targeting inflammation pharmacologically will improve cardiovascular outcomes beyond blood pressure reduction. The present review addresses recent findings regarding the pathophysiology of vascular inflammation in hypertension, focusing specifically on the role of Ang II.

Effects of aspirin and clopidogrel on plasma brain natriuretic peptide in patients with heart failure receiving ACE inhibitors

BACKGROUND

By inhibiting prostaglandins, aspirin may be deleterious in heart failure (HF) and/or may counteract angiotensin-converting enzyme (ACE) inhibitor efficacy. Conversely, clopidogrel has no effect on prostaglandin metabolism.

AIM

To investigate the effect of aspirin and clopidogrel on brain natriuretic peptide (BNP) levels in HF patients treated with ACE inhibitors.

METHODS

36 patients with stable HF (65+/-13 years, 24 males/12 females, NYHA class II to IV, ejection fraction <40%, 13 with coronary disease, all treated with ACE inhibitors) were enrolled in this prospective, double-blind study and randomised to aspirin 325 mg/day or clopidogrel 75 mg/day for 14 days. BNP was determined at day 0 and day 14.

RESULTS

19 patients were randomised to aspirin and 17 to clopidogrel. Baseline characteristics were similar in both groups. BNP levels increased in the aspirin group from day 0 to day 14 (107+/-103 to 144+/-149 pg/ml, p=0.04) whereas clopidogrel had no effect (104+/-107 and 97+/-99 pg/ml respectively, p=0.61).

CONCLUSION

This study demonstrates an adverse effect of aspirin 325 mg/day on BNP plasma levels in HF patients treated with ACE inhibitors. In contrast clopidogrel 75 mg/day had no effect.

Comparative effect of aspirin and clopidogrel on arterial function in CHF

BACKGROUND

By inhibiting prostaglandins, aspirin may be deleterious in congestive heart failure (CHF) and/or partially counteract the efficacy of angiotensin-converting enzyme inhibitors (ACEI). Conversely, clopidogrel has no effect on prostaglandin metabolism. The aim of this study was to prospectively investigate the effect of aspirin and clopidogrel on arterial functional properties in CHF patients treated with ACEI.

METHODS

Forty-five patients with stable NYHA class II-IV CHF (64.0+/-15.5 years), ejection fraction <40%, were included in this prospective double-blind study and randomized to receive aspirin 325 mg/day or clopidogrel 75 mg/day for 14 days. Reflected wave assessed by radial applanation tonometry and pulse wave velocity (PWV) were measured at day 0 and day 14.

RESULTS

Aspirin resulted in an increase in the augmentation index of the reflected wave (Delta=+3.5+/-5.2%, p=0.005) and the height above the shoulder of the reflected wave (Delta=+1.7+/-3.1 mm Hg, p=0.023), without statistically variation in PWV. Conversely, clopidogrel had no effect on the same parameters (p=0.512, p=0.677 and 0.801, respectively). Overall, variations in the augmentation index of reflected wave significantly differed when compared aspirin with clopidogrel (p=0.0261).

CONCLUSION

This study demonstrates the existence of a negative effect of aspirin 325 mg/day when compared to clopidogrel 75 mg/day on arterial functional properties in CHF patients treated with ACEI.

Aspirin Inhibits the Acute Arterial and Venous Vasodilator Response to Captopril in Patients with Chronic Heart Failure

PURPOSE

The potentially beneficial hemodynamic effects of angiotensin-converting enzyme (ACE) inhibitors in heart failure may relate, in part, to their ability to increase the production of vasodilator prostanoids. Low dose aspirin is commonly prescribed in CHF and may attenuate the vasodilator effects of ACE inhibitors. We sought to determine the effects of low dose aspirin on the peripheral hemodynamic effects of captopril in patients with chronic heart failure (CHF).

METHODS

Nine patients with chronic heart failure were randomized in a placebo controlled, cross over study, to 75 mg of aspirin daily or placebo. After 7 days treatment the response to 25 mg of captopril was evaluated over 180 min using venous occlusion plethysmography. Forearm blood flow (FBF) and forearm venous capacitance (FVC) were measured.

RESULTS

Mean arterial pressure and heart rate did not change. After placebo, FBF increased in response to captopril (+18%, 95%CI 24.2, 11.8), a response inhibited by aspirin (-1.4%, 2.9, -5.7), p < 0.005. After placebo, FVC increased in response to captopril (+7.6%, 9.8, 5.4), which was also inhibited by aspirin (+2.0%, 4.6, -0.6), aspirin vs. placebo, p = 0.02).

CONCLUSION

In patients with chronic heart failure even low dose aspirin inhibits both the acute arterial and venous dilator responses to captopril. This action of aspirin may reduce the long-term clinical benefits of ACE inhibitors.