Unraveling the Pivotal Role of Bradykinin in ACE Inhibitor Activity

ACE Inhibitors and Angiotensin Receptor Blockers for the Primary and Secondary Prevention of Cardiovascular Outcomes: Recommendations from the 2024 Egyptian Cardiology Expert Consensus in Collaboration with the CVREP Foundation

INTRODUCTION

The renin-angiotensin-aldosterone system (RAAS) plays a pivotal role in regulating blood pressure (BP), with dysregulation of RAAS resulting in hypertension and potentially heart failure (HF), myocardial infarction (MI), cardio-renal syndrome, and stroke. RAAS inhibitors, such as angiotensin-converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs), have advantages beyond BP control. However, differences between these two drug classes need to be considered when choosing a therapy for preventing cardiovascular events.

METHODS

A panel of 36 Egyptian cardiologists developed consensus statements on RAAS inhibitors for primary and secondary prevention of cardiovascular outcomes and stroke, using a modified three-step Delphi process.

RESULTS

The consensus statements highlight the importance of effective BP control and the role of RAAS blockade for prevention and management of various cardiovascular diseases. ACEis and ARBs differ in their mode of action and, thus, clinical effects. On the basis of available evidence, the consensus group recommended the following: ACEis should be considered as first choice (in preference to ARBs) to reduce the risk of MI, for primary prevention of HF, and for secondary prevention of stroke. ACEis and ARBs show equivalent efficacy for the primary prevention of stroke. Evidence also favors the preferential use of ACEis in patients with type 2 diabetes, for BP control, for the primary prevention of diabetic kidney disease, and to reduce the risk of major cardiovascular and renal outcomes. Treatment with an ACEi should be started within 24 h of ST segment elevation MI (and continued long term) in patients with HF, left ventricular systolic dysfunction, and/or diabetes. Angiotensin receptor/neprilysin inhibitors (ARNIs) are the first choice for patients with HF and reduced ejection fraction, with ACEis being the second choice in this group. ARBs are indicated as alternatives in patients who cannot tolerate ACEis. ACEis may be associated with cough development, but the incidence tends to be overestimated, and the risk can be reduced by use of a lipophilic ACEi or combining the ACEi with a calcium channel blocker.

CONCLUSION

RAAS blockade is an essential component of hypertension therapy; however, the protective effects provided by ACEis are superior to those of ARBs. Therefore, an ACEi is indicated in almost all cases, unless not tolerated.

Non-invasive in vivo imaging of changes in Collagen III turnover in myocardial fibrosis

Heart failure (HF) affects 64 million people globally with enormous societal and healthcare costs. Myocardial fibrosis, characterised by changes in collagen content drives HF. Despite evidence that collagen type III (COL3) content changes during myocardial fibrosis, in vivo imaging of COL3 has not been achieved. Here, we discovered the first imaging probe that binds to COL3 with high affinity and specificity, by screening candidate peptide-based probes. Characterisation of the probe showed favourable magnetic and biodistribution properties. The probe's potential for in vivo molecular cardiac magnetic resonance imaging was evaluated in a murine model of myocardial infarction. Using the new probe, we were able to map and quantify, previously undetectable, spatiotemporal changes in COL3 after myocardial infarction and monitor response to treatment. This innovative probe provides a promising tool to non-invasively study the unexplored roles of COL3 in cardiac fibrosis and other cardiovascular conditions marked by changes in COL3.

Angiotensin II-mediated hippocampal hypoperfusion and vascular dysfunction contribute to vascular cognitive impairment in aged hypertensive rats

INTRODUCTION

Chronic hypertension increases the risk of vascular cognitive impairment (VCI) by ∼60%; however, how hypertension affects the vasculature of the hippocampus remains unclear but could contribute to VCI.

METHODS

Memory, hippocampal perfusion, and hippocampal arteriole (HA) function were investigated in male Wistar rats or spontaneously hypertensive rats (SHR) in early (4 to 5 months old), mid (8 to 9 months old), or late adulthood (14 to 15 months old). SHR in late adulthood were chronically treated with captopril (angiotensin converting enzyme inhibitor) or apocynin (antioxidant) to investigate the mechanisms by which hypertension contributes to VCI.

RESULTS

Impaired memory in SHR in late adulthood was associated with HA endothelial dysfunction, hyperconstriction, and ∼50% reduction in hippocampal blood flow. Captopril, but not apocynin, improved HA function, restored perfusion, and rescued memory function in aged SHR.

DISCUSSION

Hippocampal vascular dysfunction contributes to hypertension-induced memory decline through angiotensin II signaling, highlighting the therapeutic potential of HAs in protecting neurocognitive health later in life.

HIGHLIGHTS

Vascular dysfunction in the hippocampus contributes to vascular cognitive impairment. Memory declines with age during chronic hypertension. Angiotensin II causes endothelial dysfunction in the hippocampus in hypertension. Angiotensin II-mediated hippocampal arteriole dysfunction reduces blood flow. Vascular dysfunction in the hippocampus impairs perfusion and memory function.

A novel metalloproteinase-derived cryptide from Bothrops cotiara venom inhibits angiotensin-converting enzyme activity

Snake venoms are primarily composed of proteins and peptides, which selectively interact with specific molecular targets, disrupting prey homeostasis. Identifying toxins and the mechanisms involved in envenoming can lead to the discovery of new drugs based on natural peptide scaffolds. In this study, we used mass spectrometry-based peptidomics to sequence 197 peptides in the venom of Bothrops cotiara, including a novel 7-residue peptide derived from a snake venom metalloproteinase. This peptide, named Bc-7a, features a pyroglutamic acid at the N-terminal and a PFR motif at the C-terminal, homologous to bradykinin. Using FRET (fluorescence resonance energy transfer) substrate assays, we demonstrated that Bc-7a strongly inhibits the two domains of angiotensin converting enzyme (Ki < 1 μM). Our findings contribute to the repertoire of biologically active peptides from snake venoms capable of inhibiting angiotensin-converting enzyme (ACE), beyond current known structural motifs and precursors. In summary, we report a novel snake venom peptide with ACE inhibitory activity, suggesting its potential contribution to the hypotensive effect observed in envenomation.

The association between ACE inhibitors and psoriasis based on the drug-targeted Mendelian randomization and real-world pharmacovigilance analyses

BACKGROUND

Although a growing number of observational studies suggest that angiotensin-converting enzyme inhibitors (ACEIs) intake may be a risk factor for psoriasis, evidence is still insufficient to draw definitive conclusions.

RESEARCH DESIGN AND METHODS

Drug-targeted Mendelian randomization (DTMR) was used to analyze the causality between genetic proxied ACEIs and psoriasis. Furthermore, we performed a disproportionality analysis based on the FDA adverse event reporting system (FAERS) database to identify more suspicious subclasses of ACEIs.

RESULTS

Using two kinds of genetic proxy instruments, the present DTMR research identified genetic proxied ACEIs as risk factors for psoriasis. Furthermore, our disproportionality analysis revealed that ramipril, trandolapril, perindopril, lisinopril, and enalapril were associated with the risk of psoriasis, which validates and refines the findings of the DTMR.

CONCLUSIONS

Our integrative study verified that ACEIs, especially ramipril, trandolapril, perindopril, lisinopril, and enalapril, tended to increase the risk of psoriasis statistically.

Protein supplementation: the double-edged sword

Protein supplements are widely consumed by athletes as well as young adults and teenagers going to the gym and are an excellent source to increase protein intake, build muscle mass, and enhance recovery. They are available in the form of powders, gummies, protein bars, and ready-to-drink shakes and have been shown to have effects on almost every system in the body. Subjects consuming whey protein-based supplements regularly show significantly lower systolic blood pressure, while subjects who consume soy-based protein supplements have been reported to show a significant decrease in their systolic and diastolic blood pressures. Favorable effects of soy protein consumption have been observed on the serum lipid profile, with significant decreases in serum low-density lipoprotein and triglyceride levels. Lower postprandial glucose levels have been observed in diabetic subjects as well, which can be attributed to the lower glycemic index of these supplements. This can lead to an indirect decrease in diabetes-related complications. While these supplements affect the body positively, caution has to be exercised while consuming them in excess, as they have been shown to cause hyperfiltration and increased urinary calcium excretion which can, in turn, lead to chronic kidney disease development. This article focuses on the effects of protein supplementation on the human body, with emphasis on the cardiovascular, endocrine, and renal systems.

Ocular posterior segment microstructural and microvascular morphological changes in protein supplement-consuming bodybuilders

BACKGROUND

To determine the effects of protein supplement (whey protein powder (PP)) on retinal, choroidal and optic nerve head (ONH) microstructure and microvascular morphology in healthy bodybuilders.

METHODS

This cross-sectional study included 23 male adults (consumers, 23 right eyes) who had been routinely consuming whey PP for bodybuilding purposes for ≥ 3 months, and 21 age- and gender-matched healthy volunteers (non-consumers, 21 right eyes) who also attended the gym but did not consume any nutritional supplements. Participants underwent standard ocular exams, enhanced depth imaging optical coherence tomography (EDI OCT), and optical coherence tomography angiography (OCTA) after ≥ 8 h of rest and fasting.

RESULTS

Whey PP was consumed for a median of 9.5 (6-12) months. Whey PP consumers had a median age of 22 (21-22) years, while non-consumers had 21 (20-22) years (p = 0.067). Whey PP consumers had greater microstructural thickness than non-consumers, with subfoveal choroidal thickness (301.40 ± 38.91 versus 278.12 ± 33.58 µm; p = 0.035) being significantly different but not central macular thickness (270.55 ± 24.60 versus 265.85 ± 12.44 µm; p = 0.402). Despite a non-significant difference in superficial and deep capillary plexus vascular densities (VDs), whey PP consumers had relatively lower VDs than non-consumers in all macular regions (p > 0.05). Despite this, whey PP consumers displayed greater ONH VDs, as well as higher global RNFL thickness (116.75 ± 10.41 versus 114.50 ± 11.70 µm) than non-consumers (p > 0.05).

CONCLUSION

Protein supplements, particularly whey PPs, appear to be associated with different changes in the retina and choroid, as well as ONH microstructural and microvascular morphology, implying that paying attention to these clinical aspects when performing ocular tests in bodybuilders who consume nutritional supplements could be critical.

The effects of whey protein on blood pressure: A systematic review and dose-response meta-analysis of randomized controlled trials

AIMS

This systematic review and dose-response meta-analysis was conducted to summarize data from available clinical trials on the effects of whey protein (WP) supplementation on blood pressure (BP) in adults.

DATA SYNTHESIS

A comprehensive literature search was conducted in the electronic databases PubMed, Web of Science, ProQuest, Embase, and SCOPUS from inception to October 2022. Weighted mean differences (WMD) and 95% confidence intervals (CI) were calculated to assess pooled effect sizes. Heterogeneity between studies was assessed using the Cochran's Q test and I2. Subgroup analysis was performed to assess potential sources of heterogeneity. The dose-response relationship was assessed using fractional polynomial modeling. Of the 2,840 records, 18 studies with 1,177 subjects were included. Pooled analysis showed that whey protein supplementation resulted in a significant reduction in systolic blood pressure (WMD: -1.54 mmHg; 95% CI: -2.85 to -0.23, p = 0.021), with significant heterogeneity between studies (I2 = 64.2%, p < 0.001), but not for diastolic blood pressure (DBP) (WMD: -0.27 mmHg; 95% CI: -1.14, 0.59, p = 0.534) with high heterogeneity between studies (I2 = 64.8%, p < 0.001). However, WP supplementation significantly reduced DBP at a dose of ˃30 g/day, in RCTs that used WP isolate powder for their intervention, in sample sizes ≤100, in studies with an intervention duration of ≤10 weeks, and in those studies that were conducted in patients with hypertension and had participants with a BMI of 25-30 kg/m2.

CONCLUSION

This meta-analysis demonstrated that WP intake significantly reduced SBP levels. Further large-scale studies are needed to specify the exact mechanism, and optimal dosage of WP supplementation to obtain a beneficial effect on BP.

Roadmap for the Management of Type 2 Diabetes and Hypertension in the Middle East: Review of the 2022 EVIDENT Summit

Type 2 diabetes mellitus (T2DM) and hypertension are leading risk factors for death and disability in the Middle East. Both conditions are highly prevalent, underdiagnosed and poorly controlled, highlighting an urgent need for a roadmap to overcome the barriers to optimal glycaemic and blood pressure management in this region. This review provides a summary of the Evidence in Diabetes and Hypertension Summit (EVIDENT) held in September 2022, which discussed current treatment guidelines, unmet clinical needs and strategies to improve treatment outcomes for patients with T2DM and hypertension in the Middle East. Current clinical guidelines recommend strict glycaemic and blood pressure targets, presenting several treatment options to achieve and maintain these targets and prevent complications. However, treatment targets are infrequently met in the Middle East, largely due to high clinical inertia among physicians and low medication adherence among patients. To address these challenges, clinical guidelines now provide individualised therapy recommendations based on drug profiles, patient preferences and management priorities. Efforts to improve the early detection of prediabetes, T2DM screening and intensive, early glucose control will minimise long-term complications. Physicians can use the T2DM Oral Agents Fact Checking programme to help navigate the wide range of treatment options and guide clinical decision-making. Sulfonylurea agents have been used successfully to manage T2DM; a newer agent, gliclazide MR (modified release formulation), has the advantages of a lower incidence of hypoglycaemia with no risk of cardiovascular events, weight neutrality and proven renal benefits. For patients with hypertension, single-pill combinations have been developed to improve efficacy and reduce treatment burden. In conjunction with pragmatic treatment algorithms and personalised therapies, greater investments in disease prevention, public awareness, training of healthcare providers, patient education, government policies and research are needed to improve the quality of care of patients with T2DM and/or hypertension in the Middle East.

Cardiovascular diseases or type 2 diabetes mellitus and chronic airway diseases: mutual pharmacological interferences

Chronic airway diseases (CAD), mainly asthma and chronic obstructive pulmonary disease (COPD), are frequently associated with different comorbidities. Among them, cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) pose problems for the simultaneous treatment of CAD and comorbidity. Indeed, there is evidence that some drugs used to treat CAD negatively affect comorbidity, and, conversely, some drugs used to treat comorbidity may aggravate CAD. However, there is also growing evidence of some beneficial effects of CAD drugs on comorbidities and, conversely, of the ability of some of those used to treat comorbidity to reduce the severity of lung disease. In this narrative review, we first describe the potential cardiovascular risks and benefits for patients using drugs to treat CAD and the potential lung risks and benefits for patients using drugs to treat CVD. Then, we illustrate the possible negative and positive effects on T2DM of drugs used to treat CAD and the potential negative and positive impact on CAD of drugs used to treat T2DM. The frequency with which CAD and CVD or T2DM are associated requires not only considering the effect that drugs used for one disease condition may have on the other but also providing an opportunity to develop therapies that simultaneously favorably impact both diseases.

Vanillin and pentoxifylline ameliorate isoproterenol-induced myocardial injury in rats via the Akt/HIF-1α/VEGF signaling pathway

Myocardial infarction (MI) is a major health problem associated with high morbidity and mortality. Recently, angiogenesis has emerged as a novel therapeutic approach against ischemic diseases including MI. Therefore, we aimed to investigate the potential angiogenic effects of vanillin (Van) both alone and in combination with pentoxifylline (PTX), and to examine the molecular mechanisms through which Van and PTX may ameliorate cardiac injury induced in rats including their effects on oxidative stress, inflammation and apoptosis which play a key role in MI pathogenesis. MI was induced in rats using isoproterenol (ISO) (150 mg kg^-1, SC, twice at a 24 h interval). Then, rats were treated orally with Van (150 mg kg^-1 day^-1), PTX (50 mg kg^-1 day^-1) or Van + PTX combination. ISO-induced cardiac injury was characterized by cardiac hypertrophy, ST-segment elevation and elevated serum levels of troponin-I, creatine kinase-MB and lactate dehydrogenase. Cardiac levels of the antioxidant markers GSH and SOD and the antiapoptotic protein Bcl-2 were decreased. On the other hand, cardiac levels of the oxidative stress marker malonaldehyde, the inflammatory cytokines TNF-α, IL-6 and IL-1β, the proapoptotic protein Bax, and caspase-3 were increased. Moreover, the cardiac levels of p-Akt and HIF-1α and the mRNA expression levels of the angiogenic genes VEGF, FGF-2 and ANGPT-1 were increased. Treatment with either Van or PTX ameliorated ISO-induced changes and further upregulated Akt/HIF-1α/VEGF signaling. Furthermore, Van + PTX combination was more effective than monotherapy. These findings suggest a novel therapeutic potential of Van and PTX in ameliorating MI through enhancing cardiac angiogenesis and modulating oxidative stress, inflammation and apoptosis.

Effect of the Renin-Angiotensin System Inhibitors on Inflammatory Markers: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To synthesize more conclusive evidence on the anti-inflammatory effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs).

METHODS

PubMed, Scopus, and Embase were searched from inception until March 1, 2021. We included randomized controlled trials (RCTs) that assessed the effect of ACEIs or ARBs, compared with placebo, on any of the following markers: C-reactive protein (CRP), interleukin 6 (IL-6), or tumor necrosis factor α (TNF-α). Mean changes in the levels of these markers were pooled as a weighted mean difference (WMD) with a 95% CI.

RESULTS

Thirty-two RCTs (n=3489 patients) were included in the final analysis. Overall pooled analysis suggested that ACEIs significantly reduced plasma levels of CRP (WMD, -0.54 [95% CI, -0.88 to -0.21]; P=.002; I²=96%), IL-6 (WMD, -0.84 [95% CI, -1.03 to -0.64]; P<.001; I²=0%), and TNF-α (WMD, -12.75 [95% CI, -17.20 to -8.29]; P<.001; I²=99%). Moreover, ARBs showed a significant reduction only in IL-6 (WMD, -1.34 [95% CI, -2.65 to -0.04]; P=.04; I²=85%) and did not significantly affect CRP (P=.15) or TNF-α (P=.97) levels. The lowering effect of ACEIs on CRP levels remained significant with enalapril (P=.006) and perindopril (P=.01) as well as with a treatment duration of less than 24 weeks (WMD, -0.67 [95% CI, -1.07 to -0.27]; P=.001; I²=94%) and in patients with coronary artery disease (WMD, -0.75 [95% CI, -1.17 to -0.33]; P<.001; I²=96%).

CONCLUSION

Based on this meta-analysis, ACEIs showed a beneficial lowering effect on CRP, IL-6, and TNF-α, whereas ARBs were effective as a class in reduction of IL-6 only.

Angiotensin Receptor Blockers in the Management of Hypertension: A Real-World Perspective and Current Recommendations

Hypertension represents a major common cardiovascular risk factor. Optimal control of high blood pressure levels is recommended to reduce the global burden of hypertensive-mediated organ damage and cardiovascular (CV) events. Among the first-line drugs recommended in international guidelines, renin-angiotensin-aldosterone system antagonists [angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs)] have long represented a rational, effective, and safe anti-hypertensive pharmacological strategy. In fact, current US and European guidelines recommend ACEi and ARBs as a suitable first choice for hypertension treatment together with calcium channel blockers (CCBs) and thiazide diuretics. Different studies have demonstrated that ARBs and ACEi exert a comparable effect in lowering blood pressure levels. However, ARBs are characterized by better pharmacological tolerability. Most importantly, the clinical evidence supports a relevant protective role of ARBs toward the CV and renal damage development, as well as the occurrence of major adverse CV events, in hypertensive patients. Moreover, a neutral metabolic effect has been reported upon ARBs administration, in contrast to other antihypertensive agents, such as beta-blockers and diuretics. These properties highlight the use of ARBs as an excellent pharmacological strategy to manage hypertension and its dangerous consequences. The present review article summarizes the available evidence regarding the beneficial effects and current recommendations of ARBs in hypertension. The specific properties performed by these agents in various clinical subsets are discussed, also including an overview of their implications for the current COVID-19 pandemic.

Does wearing a mask while exercising amid COVID-19 pandemic affect hemodynamic and hematologic function among healthy individuals? Implications of mask modality, sex, and exercise intensity

OBJECTIVES

We investigated how wearing a mask - and its modality (surgical vs. N95) - affect hemodynamic and hematologic function in males and females across two exercise intensities (submaximal (SUB) and maximal (MAX)).

METHODS

144 individuals participated in the present study and were randomly allocated to three mask groups of 48 (N95, SURGICAL, and NO MASK) with two exercise subgroups for each mask group (MAX, n = 24; SUB, n = 24) for both sexes. Participants in each experimental group (N95SUB, N95MAX; SURSUB, SURMAX; SUB, MAX) were assessed for their hemodynamic and hematologic function at baseline and during recovery after exercise.

RESULTS

No significant differences were noted for either hemodynamic or hematologic function at post-exercise as compared to baseline with regard to mask modality (P > 0.05). Heart rate (HR) for maximal intensity were significantly greater at 1 min post-exercise in N95 as compared to SURGICAL (P < 0.05). No differences were noted for hemodynamic and hematologic function with N95 and SURGICAL compared to NOMASK for either intensity (P > 0.05). Females showed significantly greater HR values at 1 min post-exercise in N95 as compared to NO MASK, but no significant differences were noted for hematological function between sexes (P > 0.05).

CONCLUSION

Our findings show that wearing a face mask (N95/surgical) while exercising has no detrimental effects on hemodynamic/hematologic function in both males and females, and suggest that wearing a mask, particularly a surgical mask, while exercising during the ongoing pandemic is safe and poses no risk to individual's health. Future studies examining physiological responses to chronic exercise with masks are warranted.

SARS-CoV-2 Infections, Impaired Tissue, and Metabolic Health: Pathophysiology and Potential Therapeutics

The SARS-CoV-2 enters the human airways and comes into contact with the mucous membranes lining the mouth, nose, and eyes. The virus enters the healthy cells and uses cell machinery to make several copies of the virus. Critically ill patients infected with SARS-CoV-2 may have damaged lungs, air sacs, lining, and walls. Since COVID-19 causes cytokine storm, it damages the alveolar cells of the lungs and fills them with fluid, making it harder to exchange oxygen and carbon dioxide. The SARS-CoV-2 infection causes a range of complications, including mild to critical breathing difficulties. It has been observed that older people suffering from health conditions like cardiomyopathies, nephropathies, metabolic syndrome, and diabetes instigate severe symptoms. Many people who died due to COVID-19 had impaired metabolic health [IMH], characterized by hypertension, dyslipidemia, and hyperglycemia, i.e., diabetes, cardiovascular system, and renal diseases making their retrieval challenging. Jeopardy stresses for increased mortality from COVID-19 include older age, COPD, ischemic heart disease, diabetes mellitus, and immunosuppression. However, no targeted therapies are available as of now. Almost two-thirds of diagnosed coronavirus patients had cardiovascular diseases and diabetes, out of which 37% were under 60. The NHS audit revealed that with a higher expression of ACE-2 receptors, viral particles could easily bind their protein spikes and get inside the cells, finally causing COVID-19 infection. Hence, people with IMH are more prone to COVID-19 and, ultimately, comorbidities. This review provides enormous information about tissue [lungs, heart and kidneys] damage, pathophysiological changes, and impaired metabolic health of SARS-CoV-2 infected patients. Moreover, it also designates the possible therapeutic targets of COVID-19 and drugs which can be used against these targets.

Mechanical activation of the angiotensin II type 1 receptor contributes to abdominal aortic aneurysm formation

Objective

The angiotensin II type 1 receptor (AT1R) can be activated under conditions of mechanical stretch in some cellular systems. Whether this activity influences signaling within the abdominal aorta to promote to abdominal aortic aneurysm (AAA) development remains unknown. We evaluated the hypothesis that mechanical AT1R activation can occur under conditions of hypertension (HTN) and contribute to AAA formation.

Methods

BPH/2 mice, which demonstrate spontaneous neurogenic, low-renin HTN, and normotensive BPN/3 mice underwent AAA induction via the calcium chloride model, with or without an osmotic minipump delivering 30 mg/kg/d of the AT1R blocker Losartan. Systolic blood pressure (SBP) was measured at baseline and weekly via a tail cuff. The aortic diameter (AoD) was measured at baseline and terminal surgery at 21 days by digital microscopy. Aortic tissue was harvested for immunoblotting (phosphorylated extracellular signal-regulated kinase-1 and -2 [pERK1/2] to ERK1/2 ratio) and expressed as the fold-change from the BPN/3 control mice. Aortic vascular smooth muscle cells (VSMCs) underwent stretch with or without Losartan (1 μM) treatment to assess the mechanical stimulation of ERK1/2 activity. Statistical analysis of the blood pressure, AoD, and VSMC ERK1/2 activity was performed using analysis of variance. However, the data distribution was determined to be log-normal (Shapiro-Wilk test) for ERK1/2 activity. Therefore, it was logarithmically transformed before analysis of variance.

Results

At baseline, the SBP was elevated in the BPH/2 mice relative to the BPN/3 mice (P < .05). Losartan treatment significantly reduced the SBP in both mouse strains (P < .05). AAA induction did not affect the SBP. At 21 days after induction, the percentage of increase in the AoD from baseline was significantly greater in the BPH/2 mice than in the BPN/3 mice (101.28% ± 4.19% vs 75.59% ± 1.67% above baseline; P < .05). Losartan treatment significantly attenuated AAA growth in both BPH/2 and BPN/3 mice (33.88% ± 2.97% and 43.96% ± 3.05% above baseline, respectively; P < .05). ERK1/2 activity was increased approximately fivefold in the BPH/2 control mice relative to the BPN/3 control mice (P < .05). In the BPH/2 and BPN/3 mice with AAA, ERK1/2 activity was significantly increased relative to the respective baseline control (P < .05) and effectively reduced by concomitant Losartan therapy (P < .05). Biaxial stretch of the VSMCs in the absence of angiotensin II demonstrated increased ERK1/2 activation (P < .05 vs static control), which was significantly inhibited by Losartan.

Conclusions

In BPH/2 mice with spontaneous neurogenic, low-renin HTN, AAA growth was amplified compared with the normotensive control and was effectively attenuated using Losartan. ERK1/2 activity was significantly elevated in the BPH/2 mice and after AAA induction in the normotensive and hypertensive mice but was attenuated by Losartan treatment. These data suggest that AT1R activation contributes to AAA development. Therefore, further investigation into this signaling pathway could establish targets for pharmacotherapeutic engineering to slow AAA growth. (JVS-Vascular Science 2021;2:194-206.).

Clinical Relevance

Hypertension (HTN) and abdominal aortic aneurysm (AAA) have been epidemiologically linked for decades; however, a biomechanical link has not yet been identified. Using a murine model of spontaneous neurogenic HTN experimentally demonstrated to have low circulating renin, mechanical activation of the angiotensin II type 1 receptor (AT1R) was identified with elevated blood pressure and AAA induction. HTN amplified AAA growth. However, more importantly, blocking the activation of AT1R with the angiotensin receptor blocker Losartan effectively abrogated AAA development. Although inhibiting the production of angiotensin II has previously been unsuccessful in altering AAA growth, the results from the present study suggest that blocking the activation of AT1R through direct ligand binding or mechanical stimulation might alter aortic wall signaling and warrants further investigation.

Angiotensin-converting enzyme inhibitors versus angiotensin receptor blockers: New-onset diabetes mellitus stratified by statin use

WHAT IS KNOWN AND OBJECTIVES

Regardless of statin use, which is known to induce hyperglycaemia, comparative studies on the risk of new-onset diabetes mellitus (NODM) with angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are needed. This study evaluated the effects of ACEIs and ARBs on NODM in the clinical setting.

METHODS

This retrospective cohort study utilized electronic medical record data from Seoul St. Mary's Hospital and Seoul National University Hospital from 2009 to 2012. Patients who were prescribed ACEIs or ARBs for the first time (irrespective of concomitant statin use) were followed up for 5 years.

RESULTS AND DISCUSSIONS

A total of 11,703 patients were included, 24.9% (n = 2916) were taking ACEIs and 75.1% (n = 9189) were taking ARBs. Patients on ACEIs had a significantly lower incidence of NODM both with statin use (HR = 0.13, p < 0.001) and without (HR = 0.15, p = 0.009) than patients on ARBs. Age ≥60 years (HR = 1.49, p = 0.010), BMI ≥25 (HR = 1.96, p < 0.010), use of calcium channel blockers (HR = 1.47, p = 0.010), and diuretics (HR = 1.48, p = 0.010) were risk factors for NODM with statin use.

WHAT IS NEW AND CONCLUSION

Patients taking ACEIs are less likely to develop NODM than patients taking ARBs, irrespective of statin use. Patients' conditions, including the risk of NODM, should be considered before prescribing ACEIs or ARBs. Future randomized clinical trials are needed to clarify further the relationship between ACEIs and ARBs and their effect on NODM.

Angiotensin-converting enzyme inhibitors from plants: A review of their diversity, modes of action, prospects, and concerns in the management of diabetes-centric complications

Angiotensin-converting enzyme (ACE) inhibitors are antihypertensive medications often used in the treatment of diabetes-related complications. Synthetic ACE inhibitors are known to cause serious side effects like hypotension, renal insufficiency, and hyperkalaemia. Therefore, there has been an intensifying search for natural ACE inhibitors. Many plants or plant-based extracts are known to possess ACE-inhibitory activity. In this review, articles focusing on the natural ACE inhibitors extracted from plants were retrieved from databases like Google Scholar, PubMed, Scopus, and Web of Science. We have found more than 50 plant species with ACE-inhibitory activity. Among them, Angelica keiskei, Momordica charantia, Muntingia calabura, Prunus domestica, and Peperomia pellucida were the most potent, showing comparatively lower half-maximal inhibitory concentration values. Among the bioactive metabolites, peptides (e.g., Tyr-Glu-Pro, Met-Arg-Trp, and Gln-Phe-Tyr-Ala-Val), phenolics (e.g., cyanidin-3-O-sambubioside and delphinidin-3-O-sambubioside), flavonoids ([-]-epicatechin, astilbin, and eupatorin), terpenoids (ursolic acid and oleanolic acid) and alkaloids (berberine and harmaline) isolated from several plant and fungus species were found to possess significant ACE-inhibitory activity. These were also known to possess promising antioxidant, antidiabetic, antihyperlipidemic and anti-inflammatory activities. Considering the minimal side effects and lower toxicity of herbal compounds, development of antihypertensive drugs from these plant extracts or phytocompounds for the treatment of diabetes-associated complications is an important endeavour. This review, therefore, focuses on the ACE inhibitors extracted from different plant sources, their possible mechanisms of action, present status, and any safety concerns.

Implications of Endothelial Cell-Mediated Dysfunctions in Vasomotor Tone Regulation

Cardiovascular diseases (CVD) constitute the major cause of death worldwide and show a higher prevalence in the adult population. The human umbilical cord consistsof two arteries and one vein, both composed of three tunics. The tunica intima, lined with endothelial cells, regulates vascular tone through the production/release of vasoregulatory substances. These substances can be vasoactive factors released by endothelial cells (ECs) that cause vasodilation (NO, PGI2, EDHF, and Bradykinin) or vasoconstriction (ET1, TXA2, and Ang II) depending on the cell type (ECs or SMC) that reacts to the stimulus. Vascular studies using ECs are important for the analysis of cardiovascular diseases since endothelial dysfunction is an important CVD risk factor. In this paper, we will address the morphological characteristics of the human umbilical cord and its component vessels. the constitution of the vascular endothelium, and the evolution of human umbilical cord-derived endothelial cells when isolated. Moreover, the role played by the endothelium in the vasomotor tone regulation, and how it may be associated with the existence of CVD, were discussed.

Sex differences in solute and water handling in the human kidney: Modeling and functional implications

The kidneys maintain homeostasis by controlling the amount of water and electrolytes in the blood. That function is accomplished by the nephrons, which transform glomerular filtrate into urine by a transport process mediated by membrane transporters. We postulate that the distribution of renal transporters along the nephron is markedly different between men and women, as recently shown in rodents. We hypothesize that the larger abundance of a renal Na+ transport in the proximal tubules in females may also better prepare them for the fluid retention adaptations required during pregnancy and lactation. Also, kidneys play a key role in blood pressure regulation, and a popular class of anti-hypertensive medications and angiotensin converting enzymes (ACE) inhibitors have been reported to be less effective in women. Model simulations suggest that the blunted natriuretic and diuretic effects of ACE inhibition in women can be attributed, in part, to their higher distal baseline transport capacity.

Novel roles of the renal angiotensin-converting enzyme

The observation that all components of the renin angiotensin system (RAS) are expressed in the kidney and the fact that intratubular angiotensin (Ang) II levels greatly exceed the plasma concentration suggest that the synthesis of renal Ang II occurs independently of the circulating RAS. One of the main components of this so-called intrarenal RAS is angiotensin-converting enzyme (ACE). Although the role of ACE in renal disease is demonstrated by the therapeutic effectiveness of ACE inhibitors in treating several conditions, the exact contribution of intrarenal versus systemic ACE in renal disease remains unknown. Using genetically modified mouse models, our group demonstrated that renal ACE plays a key role in the development of several forms of hypertension. Specifically, although ACE is expressed in different cell types within the kidney, its expression in renal proximal tubular cells is essential for the development of high blood pressure. Besides hypertension, ACE is involved in several other renal diseases such as diabetic kidney disease, or acute kidney injury even when blood pressure is normal. In addition, studies suggest that ACE might mediate at least part of its effect through mechanisms that are independent of the Ang I conversion into Ang II and involve other substrates such as N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP), Ang-(1-7), and bradykinin, among others. In this review, we summarize the recent advances in understanding the contribution of intrarenal ACE to different pathological conditions and provide insight into the many roles of ACE besides the well-known synthesis of Ang II.

A systematic review and meta-analysis of angiotensin-converting enzyme inhibitor use and psoriasis incidence

Although a considerable volume of data supporting induction or aggravation of psoriasis because of angiotensin-converting enzyme (ACE) inhibitor use exists, it remains insufficient for definitive conclusions. Therefore, we aimed to evaluate the association between ACE inhibitor use and psoriasis incidence through a systematic literature review and meta-analysis. We searched for qualifying studies across PubMed, Web of Science, and Embase. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the association between ACE inhibitor use and psoriasis incidence. Eight studies with a total of 54,509 patients with a psoriasis diagnosis were included in this meta-analysis. The pooled OR for psoriasis incidence among ACE inhibitor users was 1.52 (95% CI, 1.16–2.00) compared to that among non-users. From subgroup analysis by continent, the OR for ACE inhibitor users versus non-users was 2.37 (95% CI 1.28–4.37) in Asia. Per the subgroup analysis by climate, the OR for ACE inhibitor users vs non-users in dry climate was 3.45 (95% CI: 2.05–5.79) vs 1.32 (95% CI 1.01–1.73) in temperate climate. Our results reveal a significant association between ACE inhibitor use and psoriasis incidence.

Angiotensin-converting enzyme 2: a double-edged sword in COVID-19 patients with an increased risk of heart failure

The coronavirus disease (COVID-19) pandemic is a global health priority. Given that cardiovascular diseases (CVD) are the leading cause of morbidity around the world and that several trials have reported severe cardiovascular damage in patients infected with SARS-CoV-2, a substantial number of COVID-19 patients with underlying cardiovascular diseases need to continue their medications in order to improve myocardial contractility and to prevent the onset of major adverse cardiovascular events (MACEs), including heart failure. Some of the current life-saving medications may actually simultaneously expose patients to a higher risk of severe COVID-19. Angiotensin-converting enzyme 2 (ACE2), a key counter regulator of the renin-angiotensin system (RAS), is the main entry gate of SARS-CoV-2 into human host cells and an established drug target to prevent heart failure. In fact, ACE inhibitors, angiotensin II receptor blockers, and mineralocorticoid antagonists may augment ACE2 levels to protect organs from angiotensin II overload. Elevated ACE2 expression on the host cell surface might facilitate viral entrance, at the same time sudden nonadherence to these medications triggers MACEs. Hence, safety issues in the use of RAS inhibitors in COVID-19 patients with cardiac dysfunction remain an unsolved dilemma and need paramount attention. Although ACE2 generally plays an adaptive role in both healthy subjects and patients with systolic and/or diastolic dysfunction, we conducted a literature appraisal on its maladaptive role. Understanding the exact role of ACE2 in COVID-19 patients at risk of heart failure is needed to safely manage RAS inhibitors in frail and non-frail critically ill patients.

Establishing low-density lipoprotein apheresis tolerability in patients with prior anaphylactoid reactions to lipoprotein apheresis using magnesium sulfate

BACKGROUND

Lipoprotein apheresis (LA) tolerability is a key factor for the utilization of this therapy. Common reactions to LA are hypotension and nausea. Serious reactions include severe hypotension and anaphylactoid reactions (0.13%-1.3% and 0.2%-0.4%, respectively). The bradykinin response drives these reactions and can worsen with the use of angiotensin-converting-enzyme inhibitors. Efforts to mitigate these reactions are necessary for the tolerability of LA with a dextran sulfate-adsorption (DSA) system.

MATERIALS AND METHODS

In an effort to increase apheresis tolerability, seven patients at The University of Kansas, Department of Clinical Pharmacology, who had prior anaphylactoid reactions (defined as general cutaneous flushing, nausea/vomiting, tongue swelling, lightheadedness, and hypotension) to the DSA despite pharmacologic intervention, were treated with pre-LA intravenous magnesium adapted from a protocol developed by co-author Eliaz. This protocol consists of 1.5 g of magnesium sulfate administered over 45 minutes. All seven patients were treated with intravenous magnesium sulfate immediately before LA.

RESULTS

No episodes of anaphylactoid reactions during LA have been reported to date.

CONCLUSIONS

Magnesium infusion before DSA can be utilized to establish tolerability in patients with prior anaphylactoid reactions to LA. Proposed mechanisms include temporary stabilization of the negative-positive interactions of the dextran sulfate filter leading to a reduction of circulating bradykinin, reduction of nitric oxide, and reduction of the sympathetic response to LA.

Mitochondria as a therapeutic target for cardiac ischemia‑reperfusion injury (Review)

Acute myocardial infarction is the leading cause of cardiovascular-related mortality and chronic heart failure worldwide. As regards treatment, the reperfusion of ischemic tissue generates irreversible damage to the myocardium, which is termed 'cardiac ischemia-reperfusion (IR) injury'. Due to the large number of mitochondria in cardiomyocytes, an increasing number of studies have focused on the roles of mitochondria in IR injury. The primary causes of IR injury are reduced oxidative phosphorylation during hypoxia and the increased production of reactive oxygen species (ROS), together with the insufficient elimination of these oxidative species following reperfusion. IR injury includes the oxidation of DNA, incorrect modifications of proteins, the disruption of the mitochondrial membrane and respiratory chain, the loss of mitochondrial membrane potential (∆Ψm), Ca²⁺ over-load, mitochondrial permeability transition pore formation, swelling of the mitochondria, and ultimately, cardiomyocyte necrosis. The present review article discusses the molecular mechanisms of IR injury, and summarizes the metabolic and dynamic changes occurring in the mitochondria in response to IR stress. The mitochondria are strongly recommended as a target for the development of therapeutic agents; however, the appropriate use of agents remains a challenge.

Antihypertensive agents: a long way to safe drug prescribing in children

Recently updated clinical guidelines have highlighted the gaps in our understanding and management of pediatric hypertension. With increased recognition and diagnosis of pediatric hypertension, the use of antihypertensive agents is also likely to increase. Drug selection to treat hypertension in the pediatric patient population remains challenging. This is primarily due to a lack of large, well-designed pediatric safety and efficacy trials, limited understanding of pharmacokinetics in children, and unknown risk of prolonged exposure to antihypertensive therapies. With newer legislation providing financial incentives for conducting clinical trials in children, along with publication of pediatric-focused guidelines, literature available for antihypertensive agents in pediatrics has increased over the last 20 years. The objective of this article is to review the literature for safety and efficacy of commonly prescribed antihypertensive agents in pediatrics. Thus far, the most data to support use in children was found for angiotensin-converting enzyme inhibitors (ACE-I), angiotensin receptor blockers (ARB), and calcium channel blockers (CCB). Several gaps were noted in the literature, particularly for beta blockers, vasodilators, and the long-term safety profile of antihypertensive agents in children. Further clinical trials are needed to guide safe and effective prescribing in the pediatric population.

Centrally Acting Angiotensin-Converting Enzyme Inhibitor Suppresses Type I Interferon Responses and Decreases Inflammation in the Periphery and the CNS in Lupus-Prone Mice

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multi-organ damage. Neuropsychiatric lupus (NPSLE) is one of the most common manifestations of human SLE, often causing depression. Interferon-α (IFNα) is a central mediator in disease pathogenesis. Administration of IFNα to patients with chronic viral infections or cancers causes depressive symptoms. Angiotensin-converting enzyme (ACE) is part of the kallikrein-kinin/renin-angiotensin (KKS/RAS) system that regulates many physiological processes, including inflammation, and brain functions. It is known that ACE degrades bradykinin (BK) into inactive peptides. We have previously shown in an in vitro model of mouse bone-marrow-derived dendritic cells (BMDC) and human peripheral blood mononuclear cells that captopril (a centrally acting ACE inhibitor-ACEi) suppressed Type I IFN responsive gene (IRG) expression. In this report, we used the MRL/lpr lupus-prone mouse model, an established model to study NPSLE, to determine the in vivo effects of captopril on Type I IFN and associated immune responses in the periphery and brain and effects on behavior. Administering captopril to MRL/lpr mice decreased expression of IRGs in brain, spleen and kidney, decreased circulating and tissue IFNα levels, decreased microglial activation (IBA-1 expression) and reduced depressive-like behavior. Serotonin levels that are decreased in depression were increased by captopril treatment. Captopril also reduced autoantibody levels in plasma and immune complex deposition in kidney and brain. Thus, ACEi's may have potential for therapeutic use for systemic and NPSLE.

Understanding the Pathophysiology of COVID-19: Could the Contact System Be the Key?

To date the pathophysiology of COVID-19 remains unclear: this represents a factor determining the current lack of effective treatments. In this paper, we hypothesized a complex host response to SARS-CoV-2, with the Contact System (CS) playing a pivotal role in innate immune response. CS is linked with different proteolytic defense systems operating in human vasculature: the Kallikrein–Kinin (KKS), the Coagulation/Fibrinolysis and the Renin–Angiotensin (RAS) Systems. We investigated the role of the mediators involved. CS consists of Factor XII (FXII) and plasma prekallikrein (complexed to high-molecular-weight kininogen-HK). Autoactivation of FXII by contact with SARS-CoV-2 could lead to activation of intrinsic coagulation, with fibrin formation (microthrombosis), and fibrinolysis, resulting in increased D-dimer levels. Activation of kallikrein by activated FXII leads to production of bradykinin (BK) from HK. BK binds to B2-receptors, mediating vascular permeability, vasodilation and edema. B1-receptors, binding the metabolite [des-Arg⁹]-BK (DABK), are up-regulated during infections and mediate lung inflammatory responses. BK could play a relevant role in COVID-19 as already described for other viral models. Angiotensin-Converting-Enzyme (ACE) 2 displays lung protective effects: it inactivates DABK and converts Angiotensin II (Ang II) into Angiotensin-(1-7) and Angiotensin I into Angiotensin-(1-9). SARS-CoV-2 binds to ACE2 for cell entry, downregulating it: an impaired DABK inactivation could lead to an enhanced activity of B1-receptors, and the accumulation of Ang II, through a negative feedback loop, may result in decreased ACE activity, with consequent increase of BK. Therapies targeting the CS, the KKS and action of BK could be effective for the treatment of COVID-19.

Snake venom-derived bradykinin-potentiating peptides: A promising therapy for COVID-19?

The severe acute respiratory syndrome coronavirus‐2 (SARS‐COV‐2), a novel coronavirus responsible for the recent infectious pandemic, is known to downregulate angiotensin‐converting enzyme‐2 (ACE2). Most current investigations focused on SARS‐COV‐2‐related effects on the renin–angiotensin system and especially the resultant increase in angiotensin II, neglecting its effects on the kinin–kallikrein system. SARS‐COV‐2‐induced ACE2 inhibition leads to the augmentation of bradykinin 1‐receptor effects, as ACE2 inactivates des‐Arg9‐bradykinin, a bradykinin metabolite. SARS‐COV‐2 also decreases bradykinin 2‐receptor effects as it affects bradykinin synthesis by inhibiting cathepsin L, a kininogenase present at the site of infection and involved in bradykinin production. The physiologies of both the renin–angiotensin and kinin–kallikrein system are functionally related suggesting that any intervention aiming to treat SARS‐COV‐2‐infected patients by triggering one system but ignoring the other may not be adequately effective. Interestingly, the snake‐derived bradykinin‐potentiating peptide (BPP‐10c) acts on both systems. BPP‐10c strongly decreases angiotensin II by inhibiting ACE, increasing bradykinin‐related effects on the bradykinin 2‐receptor and increasing nitric oxide‐mediated effects. Based on a narrative review of the literature, we suggest that BPP‐10c could be an optimally effective option to consider when aiming at developing an anti‐SARS‐COV‐2 drug.

Renin-Angiotensin System in Lung Tumor and Microenvironment Interactions

The mechanistic involvement of the renin-angiotensin system (RAS) reaches beyond cardiovascular physiopathology. Recent knowledge pinpoints a pleiotropic role for this system, particularly in the lung, and mainly through locally regulated alternative molecules and secondary pathways. Angiotensin peptides play a role in cell proliferation, immunoinflammatory response, hypoxia and angiogenesis, which are critical biological processes in lung cancer. This manuscript reviews the literature supporting a role for the renin-angiotensin system in the lung tumor microenvironment and discusses whether blockade of this pathway in clinical settings may serve as an adjuvant therapy in lung cancer.

Improving sensitivity for the targeted LC-MS/MS analysis of the peptide bradykinin using a design of experiments approach

The nonapeptide bradykinin is endogenously present only in low picomolar plasma concentrations, subsequently making reliable detection using liquid chromatography coupled to mass spectrometry (LC-MS/MS) challenging. Furthermore, non-specific adsorption during sample preparation and storage can lead to unpredictable peptide losses. To overcome these issues, a design of experiments (DoE) approach was applied, which consisted of a screening to identify impacting factors, optimisation and confirmation runs. On the one hand, different injection solvent compositions and sample collection materials were investigated in order to decrease non-specific adsorption. On the other hand, the addition of modifiers, which are known to enhance the signal intensity in LC-MS/MS, to the chromatographic mobile phase was examined. Polypropylene was the most suitable material among those investigated and resulted in a factor increase of 12.0 compared to LC-MS glass. The advantages of protein low-binding polypropylene versus standard polypropylene were fully compensated by the optimisation of the injection solvent. The latter substantially contributed to a decrease of non-specific adsorption of bradykinin. In this regard, bradykinin further benefitted from an organic fraction and a high amount of formic acid. Based on the DoE results, the final optimised injection solvent-consisting of 8.7% formic acid in 49.4/5.3/36.6 water/methanol/dimethyl sulfoxide (v/v/v)-was established. Furthermore, optimisation of the mobile phase composition yielded a signal intensity increase by a factor of 7.7. The transferability of the optimisation results conducted in neat solutions were successfully confirmed in human plasma. The applicability of this approach was further supported by the successful determination of low-abundance endogenous bradykinin levels in human plasma using LC-MS/MS.

How ACE inhibitors transformed the renin-angiotensin system

The renin-angiotensin system (RAS) now underlies the successful treatment of almost 50% of the patients in cardiovascular medicine, with serious possibilities of extension to diabetes, Alzheimer's disease and cancer. This clinical transformation started just over 50 years ago, with the unexpected identification of a bradykinin-potentiating peptide from snake venom, as a potent inhibitor of ACE which led to the development of the first synthetic inhibitor, captopril, followed by the angiotensin receptor blockers. This article analyses the transformation of the RAS into its different stages, from academic experiments to clinical use and back to the laboratory, identifying the critical events involved, both clinical and scientific. The analysis also assesses the contributions of chance, coincidence, and conviction that were crucial in this transformation. Although questions remain, the transformation of the RAS over the past five decades provides a success story for medicine, for pharmacology, and, most significantly, for patients.

Hemodynamic Collapse Following Therapeutic Plasma Exchange in a Patient Receiving an Angiotensin Receptor Blocker

Therapeutic plasma exchange (TPE) is a procedure for removal of plasma and its components while leaving behind cellular elements via an apheresis device. It is used in multiple conditions one among which is systemic lupus erythematosus (SLE). Adverse reactions from TPE range from mild hypotension and fever to life-threatening cardiovascular compromise. We report the case of sudden hemodynamic collapse following TPE for a neuropsychiatric lupus flare in a patient on losartan. A 62-year-old Caucasian female with a history of drug-induced lupus presented to the hospital with symptoms of a neuropsychiatric lupus flare. She was initiated on TPE with 5% albumin based on recommendations by her rheumatologist. Shortly after TPE, she became hypotensive with poor response to fluid boluses, requiring pressor support and intubation. These symptoms resolved within 24 hours on supportive measures. This was believed to be due to losartan use on the day of TPE. The medication was discontinued and she had further sessions of TPE with no complications. Angiotensin-converting enzyme (ACE) inhibitors have previously been associated with flushing and hypotension in patients undergoing TPE. Patients undergoing TPE have an activation of the prekallikrein and bradykinin system on contact with the extracorporeal membranes. ACE inhibitors potentiate this reaction by inhibiting bradykinin catabolism. Angiotensin receptor blockers (ARBs) have also been postulated to cause elevated bradykinin levels although data pertaining to the use of ARBs in TPE is limited. We hope to highlight this rare interaction in our case and emphasize the need for further data with regard to the same.

Effects of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use on cancer therapy-related cardiac dysfunction: a meta-analysis of randomized controlled trials

Angiotensin-converting enzyme inhibitor (ACEI) and angiotensin receptor blocker (ARB) may attenuate cancer therapy-related cardiac dysfunction (CTRCD). However, results of the previous studies were not consistent. We performed a meta-analysis to evaluate the influence of ACEI/ARB on CTRCD. Randomized controlled trials (RCTs) were obtained by searching of PubMed, Embase, and Cochrane's Library databases. A random-effect model was used to pool the results. Nine RCTs with 1095 cancer patients that underwent chemotherapy with anthracycline and/or trastuzumab were included. Using of ACEI/ARB significantly preserved left ventricular ejection fraction (LVEF, weighed mean difference = 4.24%, p = 0.002) compared with controls. Subgroup analyses showed that the benefits of ACEI/ARB on LVEF following chemotherapy were consistent and independent of study characteristics including study design, sample size, cancer type, chemotherapy protocols, preventative medications of ACEI or ARB, methods for LVEF measurement, and follow-up durations. The benefits on LVEF following chemotherapy were more remarkable in studies using ACEI and followed ≤ 12 months (p for subgroup difference = 0.04 and 0.02). Use of ACEI/ARB did not significantly reduce the risk of cardiotoxicity events (risk ratio [RR] = 0.63, p = 0.22) but increased the risk of hypotension in these patients (RR = 3.94, p = 0.008). These results indicated that using of ACEI/ARB may moderately attenuate CTRCD following chemotherapy with anthracycline and/or trastuzumab. Large-scale RCTs are needed to evaluate whether the benefits of ACEI/ARB on LVEF are clinically relevant.

ACE-Triggered Hypertension Incites Stroke: Genetic, Molecular, and Therapeutic Aspects

Stroke is the second largest cause of death worldwide. Angiotensin converting enzyme (ACE) gene has emerged as an important player in the pathogenesis of hypertension and consequently stroke. It encodes ACE enzyme that converts the inactive decapeptide angiotensin I to active octapeptide, angiotensin II (Ang II). Dysregulation in the expression of ACE gene, on account of genetic variants or regulation by miRNAs, alters the levels of ACE in the circulation. Variable expression of ACE affects the levels of Ang II. Ang II acts through different signal transduction pathways via various tyrosine kinases (receptor/non-receptor) and protein serine/threonine kinases, initiating a downstream cascade of molecular events. In turn these activated molecular pathways might lead to hypertension and inflammation thereby resulting in cardiovascular and cerebrovascular diseases including stroke. In order to regulate the overexpression of ACE, many ACE inhibitors and blockers have been developed, some of which are still under clinical trials.

A Review of the Role of Bradykinin and Nitric Oxide in the Cardioprotective Action of Angiotensin-Converting Enzyme Inhibitors: Focus on Perindopril

The functional integrity of the endothelium is essential for vascular health. In addition to maintaining a delicate balance between vasodilation and vasoconstriction, the endothelium has numerous other complex roles involved in the maintenance of vascular homeostasis. Chronic exposure to cardiovascular risk factors and oxidative stress results in an imbalance in these functions, creating an environment that favors reduced vasodilation and a proinflammatory and prothrombic state. The involvement of endothelial dysfunction in all stages of the cardiovascular continuum makes it an important target for treatment. One of the major endothelial-derived factors involved in the maintenance of endothelial function is nitric oxide (NO). Angiotensin-converting enzyme (ACE) inhibitors increase NO production both directly and indirectly by preventing production of angiotensin II (which diminishes NO production) and inhibiting the degradation of bradykinin (which stimulates local release of NO). Among the ACE inhibitors, perindopril appears to have the greatest effects on bradykinin and has demonstrated efficacy in a number of markers of endothelial dysfunction including arterial stiffness and progression of atherosclerosis. There is also strong evidence supporting the use of perindopril-based therapy for the treatment of hypertension and for reducing the risk of cardiovascular morbidity and mortality in a wide range of patients across the cardiovascular continuum.Funding: The journal's Rapid Service Fee was funded by Servier.

Role of cardioprotective agents on chemotherapy-induced heart failure: A systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Although previous clinical randomized controlled trials (RCTs) have tested the effect of a variety of cardioprotective agents on cancer therapy-induced cardiotoxicity, the number of included patients was limited, and the results remained controversial. In this study, we aimed to evaluate the preventive or therapeutic effects of cardioprotective agents on heart failure (HF) caused by cardiotoxicity induced by cancer therapy.

METHODS

We included trials of the following cardioprotective drugs: Angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, beta-blockers, aldosterone antagonists and stains. We extracted the relevant information with predefined data extraction forms, and assessed the risk of bias in randomized controlled trials with the Cochrane risk of bias tool. The primary outcome was the left ventricular ejection fraction of patients after chemotherapy. We used the random-effects model to carry out pair-wise meta-analysis, and then carry out the random-effects network meta-analysis within the Bayesian framework.

RESULTS

Twenty-two relevant RCTs, including 1 916 patients (79.6 % women) with a mean age of 48.4 years, were included. Based on the evaluation of all drug species from 20 studies (26 comparisons), the analysis found that 4 therapies, aldosterone antagonists (MD, 12.78 [95 % CI, 2.87-22.69] and MD, 13.75 [95 % CI, 2.21-25.30]), ACEIs (MD, 6.79 [95 % CI, 2.11-11.48] and MD, 7.76 [95 % CI, 2.64-12.88]), statin (MD, 8.35 [95 % CI, 1.11-15.59]), and beta-blockers (MD, 4.00 [95 % CI, 0.87-7.14]), had a higher efficacy than placebo and/or control, suggesting an LVEF protective effect of cardioprotective therapy. In the analysis classified by single drug or drug combination, based on 22 studies (31 comparisons), spironolactone (MD, 12.77 [95 % CI, 1.76-23.79] and MD, 14.62 [95 % CI, 1.70-27.55]), a combination of candesartan and carvedilol (MD, 12.40 [95 % CI, 0.99-23.81]), enalapril (MD, 7.35 [95 % CI, 1.16-13.54] and MD, 9.20 [95 % CI, 2.61-15.79]), and statin (MD, 8.36 [95 % CI, 0.36-16.36]) showed significant benefits in protecting left ventricular (LV) systolic function compared with the placebo and/or control.

CONCLUSION

When classified according to drug type, aldosterone antagonists, ACEIs, statins, and beta-blockers could substantially improve the LV systolic function. In the analysis classified by single drug or drug combination, spironolactone, enalapril, and statin have a significant cardioprotective effect. However, ARBs have no cardioprotective effect and fail to improve the LVEF.

Hypotensive Snake Venom Components-A Mini-Review

Hypertension is considered a major public health issue due to its high prevalence and subsequent risk of cardiovascular and kidney diseases. Thus, the search for new antihypertensive compounds remains of great interest. Snake venoms provide an abundant source of lead molecules that affect the cardiovascular system, which makes them prominent from a pharmaceutical perspective. Such snake venom components include bradykinin potentiating peptides (proline-rich oligopeptides), natriuretic peptides, phospholipases A2, serine-proteases and vascular endothelial growth factors. Some heparin binding hypotensive factors, three-finger toxins and 5' nucleotidases can also exert blood pressure lowering activity. Great advances have been made during the last decade regarding the understanding of the mechanism of action of these hypotensive proteins. Bradykinin potentiating peptides exert their action primarily by inhibiting the angiotensin-converting enzyme and increasing the effect of endogenous bradykinin. Snake venom phospholipases A2 are capable of reducing blood pressure through the production of arachidonic acid, a precursor of cyclooxygenase metabolites (prostaglandins or prostacyclin). Other snake venom proteins mimic the effects of endogenous kallikrein, natriuretic peptides or vascular endothelial growth factors. The aim of this work was to review the current state of knowledge regarding snake venom components with potential antihypertensive activity and their mechanisms of action.

Sex-specific long-term blood pressure regulation: Modeling and analysis

Hypertension is a global health challenge: it affects one billion people worldwide and is estimated to account for >60% of all cases or types of cardiovascular disease. In part because sex differences in blood pressure regulation mechanisms are not sufficiently well understood, fewer hypertensive women achieve blood pressure control compared to men, even though compliance and treatment rates are generally higher in women. Thus, the objective of this study is to identify which factors contribute to the sexual dimorphism in response to anti-hypertensive therapies targeting the renin angiotensin system (RAS). To accomplish that goal, we develop sex-specific blood pressure regulation models. Sex differences in the RAS, baseline adosterone level, and the reactivity of renal sympathetic nervous activity (RSNA) are represented. A novel aspect of the model is the representation of sex-specific vasodilatory effect of the bound angiotensin II type two receptor (AT2R-bound Ang II) on renal vascular resistance. Model simulations suggest that sex differences in RSNA are the largest cause of female resistance to developing hypertension due to the direct influence of RSNA on afferent arteriole resistance. Furthermore, the model predicts that the sex-specific vasodilatory effects of AT2R-bound Ang II on renal vascular resistance may explain the higher effectiveness of angiotensin receptor blockers in treating hypertensive women (but not men), compared to angiotensin converting enzyme inhibitors.

Vascular legacy beyond blood pressure control: benefits of perindopril/indapamide combination in hypertensive patients with diabetes

OBJECTIVES

Much of the chronic care of patients with type 2 diabetes mellitus and hypertension involves the prevention of diabetic complications. Renin-angiotensin system inhibitors are recommended as first-line therapies because of their nephroprotective properties. Their combination with metabolically neutral diuretics is recommended to reduce blood pressure, morbidity and mortality. Our objective was to review the mechanisms by which the combination of the angiotensin-converting enzyme inhibitor, perindopril, and metabolically neutral thiazide-like diuretic, indapamide, targets the pathways involved in microvascular and macrovascular diabetic complications.

METHODS

For this narrative review, extensive literature searches were performed using PubMed/Medline. Articles published in English describing clinical trials and mechanism of action studies that were relevant to the treatment of patients with perindopril and/or indapamide were included.

RESULTS

Perindopril/indapamide treatment has been shown to reduce blood pressure and to have significant beneficial effects on arterial distensibility, kidney structure and function, and endothelial function. Recent data also suggests that perindopril may reduce the deleterious accumulation of advanced glycation end products in diabetic tissue. In the Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation diabetes trial, perindopril/indapamide treatment significantly reduced the relative risk of microvascular and macrovascular events by 9%, cardiovascular mortality by 18%, and all-cause mortality by 14%. Interestingly, 6 years after the end of the double-blind period, follow-up data showed that the beneficial effects on mortality continued to be significant even though differences in blood pressure and glycated hemoglobin levels had not been significant for several years. Together this data suggests that treatment with perindopril/indapamide has microvascular and macrovascular effects that extend beyond blood pressure lowering and that this treatment might confer a long-lasting beneficial vascular legacy.

CONCLUSION

Moving forward, understanding the pathophysiological bases of the effects that extend beyond those of blood pressure control will help us differentiate between anti-hypertensive choices.

An exploration of bioactive peptides: My collaboration with Ervin G. Erdös

This paper provides a brief historical sketch of the science of biologically active peptides. It also offers the story of how Ervin G. Erdös, a pioneer in the study of metabolism of various peptides, influenced me through collaborations that span many years. I worked in Dr. Erdös's research laboratories in Oklahoma City, Dallas, and Chicago, and we shared research interests through visits across the Atlantic between the former Yugoslavia and the United States. Among other findings, we discovered angiotensin-converting enzyme in the retina, which opened up a new research direction for many scientists interested in serious ocular diseases. This tribute to my mentor paints a portrait of a man who, in addition to his dedication to science and his seminal discoveries about the metabolism of peptides, took the time to invest in training many young scientists. His fine personal qualities explain why all of those who worked with him hold him in such high regard.

B2-kinin receptors in the dorsal periaqueductal gray are implicated in the panicolytic-like effect of opiorphin

Reported results have shown that the pentapeptide opiorphin inhibits oligopeptidases that degrade brain neuropeptides, and has analgesic and antidepressant effects in experimental animals, without either tolerance or dependency after chronic administration. In a previous study we showed that opiorphin has a panicolytic-like effect in the dorsal periaqueductal gray (dPAG) electrical stimulation test (EST), mediated by the μ-opioid receptor (MOR). This study further analyzes the mechanism of opiorphin panicolytic action, using the EST and drug injection inside the dPAG. The obtained results showed that blockade of the 5-HT_1A receptors with WAY-100635 did not change the escape-impairing effect of opiorphin, and combined injection of sub-effective doses of opiorphin and the 5-HT_1A-agonist 8-OH-DPAT did not have a significant anti-escape effect. In contrast, the anti-escape effect of opiorphin was antagonized by pretreatment with the kinin B2 receptor blocker HOE-140, and association of sub-effective doses of opiorphin and bradykinin caused a significant anti-escape effect. The anti-escape effect of bradykinin was not affected by previous administration of WAY-100635. Therefore, the anti-escape effect of opiorphin in the dPAG seems to be mediated by endogenous bradykinin, acting on kinin B2 receptors, which previous results have shown to interact synergistically with MOR in the dPAG to restrain escape in two animal models of panic. Chemical compounds: Opiorphin (PubChem CID: 25195667); WAY100635 maleate salt (PubChem CID: 11957721); 8-OH-DPAT hydrobromide (PubChem CID: 6917794); Bradykinin (PubChem CID: 439201); HOE-140 (Icatibant) (PubChem CID: 6918173).

Panicolytic-like action of bradykinin in the dorsal periaqueductal gray through μ-opioid and B2-kinin receptors

A wealth of evidence has shown that opioid and kinin systems may control proximal defense in the dorsal periaqueductal gray matter (dPAG), a critical panic-associated area. Studies with drugs that interfere with serotonin-mediated neurotransmission suggest that the μ-opioid receptor (MOR) synergistically interacts with the 5-HT_1A receptor in the dPAG to inhibit escape, a panic-related behavior. A similar inhibitory effect has also been reported after local administration of bradykinin (BK), which is blocked by the non-selective opioid receptor antagonist naloxone. The latter evidence, points to an interaction between BK and opioids in the dPAG. We further explored the existence of this interaction through the dPAG electrical stimulation model of panic. We also investigated whether intra-dPAG injection of captopril, an inhibitor of the angiotensin-converting enzyme (ACE) that also degrades BK, causes a panicolytic-like effect. Our results showed that intra-dPAG injection of BK inhibited escape performance in a dose-dependent way, and this panicolytic-like effect was blocked by the BK type 2 receptor (B2R) antagonist HOE-140, and by the selective MOR antagonist CTOP. Conversely, the panicolytic-like effect caused by local administration of the selective MOR agonist DAMGO was antagonized by pre-treatment with either CTOP or HOE-140, indicating cross-antagonism between MOR and B2R. Finally, intra-dPAG injection of captopril also impaired escape in a dose-dependent way, and this panicolytic-like effect was blocked by pretreatment with HOE-140, suggesting mediation by endogenous BK. The panicolytic-like effect of captopril indicates that the use of ACE inhibitors in the clinical management of panic disorder may be worth exploring.

Kallikrein-kinin system as the dominant mechanism to counteract hyperactive renin-angiotensin system

The renin-angiotensin system (RAS) generates, maintains, and makes worse hypertension and cardiovascular diseases (CVDs) through its biologically active component angiotensin II (Ang II), that causes vasoconstriction, sodium retention, and structural alterations of the heart and the arteries. A few endogenous vasodilators, kinins, natriuretic peptides, and possibly angiotensin (1-7), exert opposite actions and may provide useful therapeutic agents. As endothelial autacoids, the kinins are potent vasodilators, active natriuretics, and protectors of the endothelium. Indeed, the kallikrein-kinin system (KKS) is considered the dominant mechanism for counteracting the detrimental effects of the hyperactive RAS. The 2 systems, RAS and KKS, are controlled by the angiotensin-converting enzyme (ACE) that generates Ang II and inactivates the kinins. Inhibitors of ACE can reduce the impact of Ang II and potentiate the kinins, thus contributing to restore the cardiovascular homeostasis. In the last 20 years, ACE-inhibitors (ACE-Is) have become the drugs of first choice for the treatments of the major CVDs. ACE-Is not only reduce blood pressure, as sartans also do, but by protecting and potentiating the kinins, they can reduce morbidity and mortality and improve the quality of life for patients with CVDs. This paper provides a brief review of the literature on this topic.

Support for involvement of the renin-angiotensin system in dysplastic Barrett's esophagus

BACKGROUND AND AIM

Patients with dysplasia in Barrett's esophagus (BE) have a considerable risk of developing esophageal adenocarcinoma (EAC). The mucosal expression of the pro-inflammatory angiotensin II receptor type 1 (AT1R) is elevated in these patients, suggesting a role in carcinogenesis. The purpose of this study was to determine whether interference with the renin-angiotensin system (RAS) would influence downstream markers of carcinogenesis.

METHODS

Endoscopic mucosal biopsies from BE patients with low-grade dysplasia (LGD) were sampled before and after a three-week period of RAS-interfering treatment. Thirty patients were randomly allocated to enalapril (ACE inhibitor, 5 mg od), candesartan (AT1R antagonist, 8 mg od), or no drug. The expression of 12 proteins known to be associated with RAS and carcinogenesis was assessed using western blot.

RESULTS

We found altered expression of several proteins after enalapril treatment (decreased: NFκB, p = .043; NLRP3, p = .050; AMACR, p = .017; and caspase 3, p = .025; increased: p53, p = .050). Candesartan treatment was associated with increased iNOS expression (p = .033). No significant changes were seen in the no-drug group.

CONCLUSION

Interference with angiotensin II formation was associated with altered expression of inflammation- and carcinogenesis-related proteins. The present results speak in favor of involvement of angiotensin II in BE dysplasia, but the role of AT1R should be investigated further.

Effects of Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers on Prothrombotic Processes and Myocardial Infarction Risk

Acute ischemic events occur most frequently at dawn and in the early hours of the morning. The development of these severe clinical events exhibits a temporal relationship with changes in various hemodynamic, prothrombotic, and hormonal processes. The authors highlight not only these relationships but also the potential protective effect of increased bradykinin levels and the inhibition of different angiotensin II (AT-II) receptors (AT2, AT4) against unfavorable prothrombotic influences, which—based on studies to date—decreases the risk of acute cardiovascular events. Comparisons are presented between the different effects of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on factors that influence thrombus formation and myocardial infarction risk.