RAS blockade with ARB and ACE inhibitors: current perspective on rationale and patient selection

Discontinuation of afterload-reducing drugs decreases left ventricular outflow tract obstruction in hypertrophic obstructive cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM), the most common genetic heart disease, is classified into hypertrophic non-obstructive and hypertrophic obstructive cardiomyopathy (HOCM). Patients with HOCM and coexisting heart failure or arterial hypertension are often prescribed afterload-reducing drugs. Although recommended in current guidelines, data on the direct effect of discontinuing afterload-reducing medication are scarce. This study aims to demonstrate the benefit of discontinuing afterload-reducing medication in HOCM patients.

Methods

This monocentric retrospective analysis included 24 patients with HOCM with afterload-reducing medication, including angiotensin-converting enzyme inhibitors, angiotensin-1 receptor blocker and dihydropyridine-calcium channel blocker, at their first outpatient visit. Effects of discontinuing this medication on LVOTO were examined compared to patients with persistent use despite medical advice.

Results

16 patients discontinued their afterload-reducing drugs, resulting in a significant decrease in median LVOT gradient from 86.5 [60.5-109.3] mmHg to 61.5 [28.3-97.50] mmHg (p = 0.0004). In 6 patients, beta-blocker therapy was initiated simultaneously, or the dose was increased. Regardless, LVOT gradient reduction was also significant in the remaining 10 patients (p = 0.001). The gradient was not changed significantly in the 8 patients continuing their afterload-reducing medication.

Conclusions

Discontinuation of afterload-reducing drugs significantly decreases LVOTO. Our study underscores the significance of abstaining from afterload-reducing drugs in HOCM patients, particularly in patients with concomitant hypertension or heart failure. According to recently published European guidelines, HOCM patients should preferably be treated with beta-blockers or non-dihydropyridine-calcium channel blockers.

The Renoprotective Mechanisms of Sodium-Glucose Cotransporter-2 Inhibitors (SGLT2i)-A Narrative Review

Chronic kidney disease (CKD) is a noncommunicable condition that has become a major healthcare burden across the globe, often underdiagnosed and associated with low awareness. The main cause that leads to the development of renal impairment is diabetes mellitus and, in contrast to other chronic complications such as retinopathy or neuropathy, it has been suggested that intensive glycemic control is not sufficient in preventing the development of diabetic kidney disease. Nevertheless, a novel class of antidiabetic agents, the sodium-glucose cotransporter-2 inhibitors (SGLT2i), have shown multiple renoprotective properties that range from metabolic and hemodynamic to direct renal effects, with a major impact on reducing the risk of occurrence and progression of CKD. Thus, this review aims to summarize current knowledge regarding the renoprotective mechanisms of SGLT2i and to offer a new perspective on this innovative class of antihyperglycemic drugs with proven pleiotropic beneficial effects that, after decades of no significant progress in the prevention and in delaying the decline of renal function, start a new era in the management of patients with CKD.

Potentials of Natural Antioxidants in Reducing Inflammation and Oxidative Stress in Chronic Kidney Disease

Chronic kidney disease (CKD) presents a substantial global public health challenge, with high morbidity and mortality. CKD patients often experience dyslipidaemia and poor glycaemic control, further exacerbating inflammation and oxidative stress in the kidney. If left untreated, these metabolic symptoms can progress to end-stage renal disease, necessitating long-term dialysis or kidney transplantation. Alleviating inflammation responses has become the standard approach in CKD management. Medications such as statins, metformin, and GLP-1 agonists, initially developed for treating metabolic dysregulation, demonstrate promising renal therapeutic benefits. The rising popularity of herbal remedies and supplements, perceived as natural antioxidants, has spurred investigations into their potential efficacy. Notably, lactoferrin, Boerhaavia diffusa, Amauroderma rugosum, and Ganoderma lucidum are known for their anti-inflammatory and antioxidant properties and may support kidney function preservation. However, the mechanisms underlying the effectiveness of Western medications and herbal remedies in alleviating inflammation and oxidative stress occurring in renal dysfunction are not completely known. This review aims to provide a comprehensive overview of CKD treatment strategies and renal function preservation and critically discusses the existing literature's limitations whilst offering insight into the potential antioxidant effects of these interventions. This could provide a useful guide for future clinical trials and facilitate the development of effective treatment strategies for kidney functions.

A Comprehensive Retrospective Study on the Mechanisms of Cyclic Mechanical Stretch-Induced Vascular Smooth Muscle Cell Death Underlying Aortic Dissection and Potential Therapeutics for Preventing Acute Aortic Aneurysm and Associated Ruptures

Acute aortic dissection (AAD) and associated ruptures are the leading causes of death in cardiovascular diseases (CVDs). Hypertension is a prime risk factor for AAD. However, the molecular mechanisms underlying AAD remain poorly understood. We previously reported that cyclic mechanical stretch (CMS) leads to the death of rat aortic smooth muscle cells (RASMCs). This review focuses on the mechanisms of CMS-induced vascular smooth muscle cell (VSMC) death. Moreover, we have also discussed the potential therapeutics for preventing AAD and aneurysm ruptures.

Nephrotoxic drug burden and predictors of exposure among patients with renal impairment in Ethiopia: A multi-center study

Background

Nephrotoxic drugs may hasten the decline in kidney function and worsen the progression of renal impairment as a result; these drugs should be avoided or used with caution in patients with pre-existing renal insufficiency. The purpose of this study was to assess the burden of nephrotoxic medication use and its predictors among patients with underlying renal impairment.

Methods

A multicenter, institution-based, cross-sectional study was conducted from May 30, 2021 to July 30, 2021, at medical wards. Renal impaired patients admitted during the data collection period who took at least one medication were enrolled in the study. A simple random sampling technique was used to select the study participants. Data was collected through an interview and a medical card review. Both bivariable and multivariable binary logistic regression analyses were fitted to identify factors associated with nephrotoxic drug use.

Results

Among the 422 participants, more than half of them (53.6 %) were male. The mean patient's age was 47.5 (±16.7) years. A total of 1310 drugs were prescribed for 422 patients with renal impairment, of which 80.15 % were nephrotoxic. Nephrotoxic drugs were prescribed for 66.4 % of patients. The burden of nephrotoxic medication prescription was significantly associated with variables like the presence of comorbidity (AOR = 6.31, 95 % CI: 2.01-19.79), the number of medications prescribed (AOR = 1.43, 95 % CI: 1.05-1.93), and the age of participants (AOR = 1.12, 95 % CI: 1.07-1.17).

Conclusion

The present study demonstrated that two-third of the patients with renal impairment were exposed to nephrotoxic medications. Furosemide, Enalapril, and vancomycin were the most frequently prescribed nephrotoxic medications. The study suggests that prescribers need to give special attention to older patients who have underlying renal insufficiency, a comorbid condition, and polypharmacy regarding exposure to contraindicated nephrotoxic medication.

Decoding Angiotensin Receptors: TOMAHAQ-Based Detection and Quantification of Angiotensin Type-1 and Type-2 Receptors

Background The renin-angiotensin system plays a crucial role in human physiology, and its main hormone, angiotensin, activates 2 G-protein-coupled receptors, the angiotensin type-1 and type-2 receptors, in almost every organ. However, controversy exists about the location, distribution, and expression levels of these receptors. Concerns have been raised over the low sensitivity, low specificity, and large variability between lots of commercially available antibodies for angiotensin type-1 and type-2 receptors, which makes it difficult to reconciliate results of different studies. Here, we describe the first non-antibody-based sensitive and specific targeted quantitative mass spectrometry assay for angiotensin receptors. Methods and Results Using a technique that allows targeted analysis of multiple peptides across multiple samples in a single mass spectrometry analysis, known as TOMAHAQ (triggered by offset, multiplexed, accurate mass, high resolution, and absolute quantification), we have identified and validated specific human tryptic peptides that permit identification and quantification of angiotensin type-1 and type-2 receptors in biological samples. Several peptide sequences are conserved in rodents, making these mass spectrometry assays amenable to both preclinical and clinical studies. We have used this method to quantify angiotensin type-1 and type-2 receptors in postmortem frontal cortex samples of older adults (n=28) with Alzheimer dementia. We correlated levels of angiotensin receptors to biomarkers classically linked to renin-angiotensin system activation, including oxidative stress, inflammation, amyloid-β load, and paired helical filament-tau tangle burden. Conclusions These robust high-throughput assays will not only catalyze novel mechanistic studies in the angiotensin research field but may also help to identify patients with an unbalanced angiotensin receptor distribution who would benefit from angiotensin receptor blocker treatment.

Evaluation of Endothelial Progenitor Cell Characteristics as Clinical Biomarkers for Elderly Patients with Ischaemic Stroke

Ageing impairs endothelial function and predisposes the person to ischaemic stroke (IS). Endothelial progenitor cells (EPCs) repair endothelial damage and induce post-ischaemic neovascularisation. Given the prevalence of IS in older population, this study explored whether changes in EPC number and function may reliably predict the type or outcome of stroke in patients ≥ 65 years of age. For this, blood samples were collected once from healthy volunteers (HVs, n = 40) and four times (admission and days 7, 30 and 90 post-stroke) from participants with lacunar (n = 38) or cortical (n = 43) stroke. EPCs were counted with flow cytometry and defined as non-haematopoietic cells (CD45-) expressing markers for stemness (CD34 +), immaturity (CD133 +) and endothelial maturity (KDR +). Clonogenesis, tubulogenesis, migration and proliferation assays were performed as measures of EPC functionality. Biochemical profile of plasma inflammatory and angiogenic agents were studied using specific ELISAs. Primary outcome was disability or dependence on day 90 post-stroke, assessed by the modified Rankin Scale (mRS). Compared to HVs, EPC numbers were higher in stroke patients at all time points studied, reaching significance at baseline and day 30. No differences in EPC counts and functionality were observed between lacunar and cortical stroke groups at any time. Plasma endostatin, PDGF-BB, TNF-α and VEGF levels were higher in stroke patients vs HVs. Patient outcome, evaluated by mRS on day 90 post-stroke, did not correlate with EPC count or functionality. Baseline EPC counts may serve as a diagnostic marker for stroke but fail to distinguish between different stroke subtypes and predict post-stroke outcome.

Molecular Mechanisms and Therapeutic Implications of Endothelial Dysfunction in Patients with Heart Failure

Heart failure is a complex medical syndrome that is attributed to a number of risk factors; nevertheless, its clinical presentation is quite similar among the different etiologies. Heart failure displays a rapidly increasing prevalence due to the aging of the population and the success of medical treatment and devices. The pathophysiology of heart failure comprises several mechanisms, such as activation of neurohormonal systems, oxidative stress, dysfunctional calcium handling, impaired energy utilization, mitochondrial dysfunction, and inflammation, which are also implicated in the development of endothelial dysfunction. Heart failure with reduced ejection fraction is usually the result of myocardial loss, which progressively ends in myocardial remodeling. On the other hand, heart failure with preserved ejection fraction is common in patients with comorbidities such as diabetes mellitus, obesity, and hypertension, which trigger the creation of a micro-environment of chronic, ongoing inflammation. Interestingly, endothelial dysfunction of both peripheral vessels and coronary epicardial vessels and microcirculation is a common characteristic of both categories of heart failure and has been associated with worse cardiovascular outcomes. Indeed, exercise training and several heart failure drug categories display favorable effects against endothelial dysfunction apart from their established direct myocardial benefit.

Clinical impact of suboptimal RAASi therapy following an episode of hyperkalemia

BACKGROUND

Hyperkalemia (HK) is a barrier to optimization of renin-angiotensin-aldosterone system inhibitor (RAASi) therapy in heart failure (HF) and chronic kidney disease (CKD). We investigated cardiorenal risk associated with changes in RAASi regimen after an episode of HK in patients with HF and/or CKD.

METHODS

This observational study utilized data from hospital records, claims, and health registers from the US (Optum's de-identified Market Clarity Data) and Japan (Medical Data Vision). Included patients had an index episode of HK between July 2019 and September 2021 (US), or May 2020 and September 2021 (Japan), with prior diagnosis of HF or CKD (stage 3 or 4), and RAASi use. Risk of a cardiorenal composite outcome (HF emergency visit, HF hospitalization, or progression to end-stage kidney disease) was determined in patients who discontinued RAASi, down-titrated their dose by > 25%, or maintained or up-titrated their dose following the HK episode.

RESULTS

A total of 15,488 and 6020 patients were included from the US and Japan, respectively. Prior to the episode of HK, 59% (US) and 27% (Japan) of patients had achieved > 50% target RAASi dose. Following the episode of HK, 33% (US) and 32% (Japan) of patients did not fill a new RAASi prescription. Risk of the cardiorenal outcome at 6 months was higher in patients who discontinued or down-titrated versus maintained or up-titrated RAASi treatment both in the US (17.5, 18.3, and 10.6%; p <  0.001) and in Japan (19.7, 20.0, and 15.1%; p <  0.001).

CONCLUSION

HK-related RAASi discontinuation or down-titration was associated with higher risk of cardiorenal events versus maintained or up-titrated RAASi.

Angiotensin II type 1a receptor deficiency alleviates muscle atrophy after denervation

The study aim was to determine if suppressed activation of angiotensin II type 1 receptor (AT1) prevents severe muscle atrophy after denervation. The sciatic nerves in right and left inferior limbs were cut in AT1a knockout homo (AT1a^-/-) male mice and wild-type (AT1a^+/+) male mice. Muscle weight and cross-sectional areas of type IIb muscle fibers in gastrocnemius muscle decreased at 7 and 21 days postdenervation in both AT1a^-/- mice and AT1a^+/+ mice, and the reduction was significantly attenuated in the denervated muscles of AT1a^-/- mice compared to the AT1a^+/+ mice. Gene expressions in the protein degradation system [two E3 ubiquitin ligases (muscle RING-finger protein-1 and Atrogin-1)] upregulated at 7 days postdenervation in all denervated mice were significantly lower in AT1a^-/- mice than in AT1a^+/+ mice. Activations of nuclear factor κB and Forkhead box subgroup O1, and protein expression of monocyte chemoattractant protein-1 were significantly suppressed in the AT1a^-/- mice compared with those in the AT1a^+/+ mice. In addition, suppressed apoptosis, lower infiltration of M1 macrophages, and higher infiltration of M2 macrophages were significantly observed at 21 days postdenervation in the AT1a^-/- mice compared with those in the AT1a^+/+ mice. In conclusion, the AT1 receptor deficiency retarded muscle atrophy after denervation.

Impact of secondary prevention medical therapies on outcomes of patients suffering from Myocardial Infarction with NonObstructive Coronary Artery disease (MINOCA): A meta-analysis

AIMS

To assess the impact of secondary prevention medical therapies (statins, ACE-inhibitors/Angiotensin Receptor Blockers (ARB), beta-blockers (BB) and Dual Antiplatelet Therapy (DAPT)) on outcomes of patients with myocardial infarction with nonobstructive coronary artery disease (MINOCA).

METHODS

Five adjusted observational studies encompassing 10,546 were included in this meta-analysis. All-cause death was the primary endpoint, while Major Adverse Cardiovascular Events (MACE) and acute myocardial infarction (AMI) were the secondary endpoints.

RESULTS

After 24 months of follow up, statins (tested in 8093 patients) were associated with a reduced risk of all-cause death (HR 0.60:0.45-0.81, p 〈0,001), while ACE-inhibitors/ARB (on 9666 patients) were not. Aggregate data from two studies (n = 9720, 7719 on beta-blockers, 6423 on DAPT) indicated that beta-blockers and DAPT (median follow-up 34.1 and 15.7 months, respectively) were both associated with a significant reduction of all-cause death (HR0.81:0.66-0.99, p = 0.04, and HR0.73:0.55-0.98, p = 0.03, for beta-blockers and DAPT, respectively). Among the investigated therapies, only ACE-inhibitors/ARBs entailed a reduced risk of MACE (HR0.65:0.44-0.94, p = 0.02, all CI 95%) over 36.5 months (four studies, n = 10,150). None of the investigated therapies was associated with a reduced risk of AMI.

CONCLUSIONS

Data from adjusted observational studies suggest that beta-blockers, statins and DAPT are associated with a survival benefit among MINOCA patients. ACE-inhibitors/ARB entail a reduced risk of MACE while none of the investigated secondary prevention therapies is associated with a reduced risk of AMI. Randomized controlled trials are warranted to confirm these findings.

Functional ACE2 deficiency leading to angiotensin imbalance in the pathophysiology of COVID-19

SARS-CoV-2, the virus responsible for COVID-19, uses angiotensin converting enzyme 2 (ACE2) as its primary cell-surface receptor. ACE2 is a key enzyme in the counter-regulatory pathway of the broader renin-angiotensin system (RAS) that has been implicated in a broad array of human pathology. The RAS is composed of two competing pathways that work in opposition to each other: the "conventional" arm involving angiotensin converting enzyme (ACE) generating angiotensin-2 and the more recently identified ACE2 pathway that generates angiotensin (1-7). Following the original SARS pandemic, additional studies suggested that coronaviral binding to ACE2 resulted in downregulation of the membrane-bound enzyme. Given the similarities between the two viruses, many have posited a similar process with SARS-CoV-2. Proponents of this ACE2 deficiency model argue that downregulation of ACE2 limits its enzymatic function, thereby skewing the delicate balance between the two competing arms of the RAS. In this review we critically examine this model. The available data remain incomplete but are consistent with the possibility that the broad multisystem dysfunction of COVID-19 is due in large part to functional ACE2 deficiency leading to angiotensin imbalance with consequent immune dysregulation and endothelial cell dysfunction.

Angiotensin-Converting Enzyme Inhibitor and Angiotensin Receptor Blocker Use Associated with Reduced Mortality and Other Disease Outcomes in US Veterans with COVID-19

Objective

To determine the association between angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) use and coronavirus disease 2019 (COVID-19) severity and outcomes in US veterans.

Patients and Methods

We retrospectively examined 27,556 adult US veterans who tested positive for COVID-19 between March to November 2020. Logistic regression and Cox proportional hazards models using propensity score (PS) for weight, adjustment, and matching were used to examine the odds of an event within 60 days following a COVID-19–positive case date and time to death, respectively, according to ACEI and/or ARB prescription within 6 months prior to the COVID-19–positive case date.

Results

The overlap PS weighted logistic regression model showed lower odds of an intensive care unit (ICU) admission (odds ratio [OR] 95% CI 0.77, 0.61–0.98) and death within 60 days (0.87, 0.79–0.97) with an ACEI or ARB prescription. Veterans with an ARB-only prescription also had lower odds of an ICU admission (0.64, 0.44–0.92). The overlap PS weighted model similarly showed a lower risk of time to all-cause mortality in veterans with an ACEI or ARB prescription (HR [95% CI]: 0.87, 0.79–0.97) and an ARB only prescription (0.78, 0.67–0.91). Veterans with an ACEI prescription had higher odds of experiencing a septic event within 60 days after the COVID-19–positive case date (1.22, 1.02–1.46).

Conclusion

In this study of a national cohort of US veterans, we found that the use of an ACEI/ARB in patients with COVID-19 was not associated with increased mortality and other worse outcomes. Future studies should examine underlying pathways and further confirm the relationship of ACEI prescription with sepsis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40265-021-01639-2.

Алгоритмы лечения системной склеродермии при преимущественном поражении кожи и суставов, при синдроме Рейно и дигитальных язвах согласно современным рекомендациям

Системная склеродермия (ССД) (системный склероз) является уникальным заболеванием среди ревматических болезней, поскольку представляет проблему менеджмента хронической мультисистемной аутоиммунной патологии с широко распространенной облитерирующей васкулопатией малых артерий, связанной с разной степенью фиброза тканей. В патологический процесс могут вовлекаться все органы, так или иначе связанные с соединительной тканью и имеющие кровеносные сосуды. Прогрессирующее течение ССД приводит к развитию необратимых фиброзных изменений, в результате которых происходит нарушение функции пораженных органов. Отличительной чертой ССД является клиническая неоднородность подгрупп больных, которые различаются в зависимости от степени тяжести заболевания, вовлечения тех или иных органов и систем и дальнейшего прогноза. Врач должен тщательно обследовать каждого пациента с ССД для определения конкретных проявлений и уровня активности заболевания для назначения соответствующего лечения. В настоящее время использование алгоритмов лечения является современной стратегией ведения пациентов, особенно после неудачного использования препаратов первой линии. При ранней активной диффузной склеродермии с преимущественным поражением кожи следует отдать предпочтение метотрексату (МТХ) в качестве препарата первой линии, а при его неэффективности или непереносимости препаратом второй линии является мофетила микофенолат (ММФ), при неэффективности последнего препаратом третьей линии является внутривенный циклофосфамид. Следует заметить, что при тяжелом поражении кожи препаратом первой линии является ММФ, а МТХ — вторым, при неэффективности ММФ. На сегодняшний день блокаторы кальциевых каналов (БКК), главным образом нифедипин, остаются препаратами первой линии для терапии синдрома Рейно при ССД. При неэффективности этих лекарственных средств следует добавить ингибиторы фосфодиэстеразы-5 (иФДЕ-5), следующим шагом терапии является назначение ингибиторов ангиотензинпревращающего фермента или блокаторов рецепторов ангиотензина. При неэффективности комбинированной терапии БКК и иФДЕ-5, при тяжелом течении синдрома Рейно следует использовать простаноиды. Препаратом первой линии для лечения артрита, как и для поражения кожи, является МТХ, при его неэффективности или высокой воспалительной активности следует добавить глюкокортикоиды и нестероидные противовоспалительные препараты. Гидроксихинолон является препаратом третьей линии, его добавляют к терапии при неэффективности вышеперечисленных агентов. Биологические агенты (ритуксимаб и тоцилизумаб) являются препаратами четвертой линии лечения артрита, ассоциированного с ССД.

Revealing new therapeutic opportunities in hypertension through network-driven integrative genetic analysis and drug target prediction approach

Epidemiological studies have established that untreated hypertension (HTN) is a major independent risk factor for developing cardiovascular diseases (CVD), stroke, renal failure, and other conditions. Several important studies have been published to prevent and manage HTN; however, antihypertensive agents' optimal choice remains controversial. Therefore, the present study is undertaken to update our knowledge in the primary treatment of HTN, specifically in the setting of other three important diseases. MicroRNAs (miRNAs) are remarkably stable short endogenous conserved non-coding RNAs that bind to the mRNA at its (3' UTR) to regulate its gene expression by causing translational repression or mRNA degradation. Through their coordinated activities on different pathways and networks, individual miRNAs control normal and pathological cellular processes. Therefore, to identify the critical miRNA-mRNA-TF interactions, we performed systematic bioinformatics analysis. We have also employed the molecular modelling and docking approach to identify the therapeutic target that delivers novel empathies into Food and Drug Administration approved and herbal drug response physiology. Gene Expression Omnibus (GEO) was employed to identify the differentially expressed genes (DEGs) and hub genes- KNG1, HLA-DPB1, CXCL8, IL1B, and BCL2. The HTN associated feed-forward loop (FFL) network included miR-9-5p, KNG1 and AR. We employed high throughput screening to get the best interacting compounds, telmisartan and limonin, that provided a significant docking score (-13.3 and -12.0 kcal/mol) and a potential protective effect that may help to combat the impact of HTN. The present study provides novel insight into HTN etiology through the identification of mRNAs and miRNAs and associated pathways.

Vascular control of kidney epithelial transporters

A major pathway in hypertension pathogenesis involves direct activation of ANG II type 1 (AT1) receptors in the kidney, stimulating Na+ reabsorption. AT1 receptors in tubular epithelia control expression and stimulation of Na+ transporters and channels. Recently, we found reduced blood pressure and enhanced natriuresis in mice with cell-specific deletion of AT1 receptors in smooth muscle (SMKO mice). Although impaired vasoconstriction and preserved renal blood flow might contribute to exaggerated urinary Na+ excretion in SMKO mice, we considered whether alterations in Na+ transporter expression might also play a role; therefore, we carried out proteomic analysis of key Na+ transporters and associated proteins. Here, we show that levels of Na+-K+-2Cl- cotransporter isoform 2 (NKCC2) and Na+/H+ exchanger isoform 3 (NHE3) are reduced at baseline in SMKO mice, accompanied by attenuated natriuretic and diuretic responses to furosemide. During ANG II hypertension, we found widespread remodeling of transporter expression in wild-type mice with significant increases in the levels of total NaCl cotransporter, phosphorylated NaCl cotransporter (Ser71), and phosphorylated NKCC2, along with the cleaved, activated forms of the α- and γ-epithelial Na+ channel. However, the increases in α- and γ-epithelial Na+ channel with ANG II were substantially attenuated in SMKO mice. This was accompanied by a reduced natriuretic response to amiloride. Thus, enhanced urinary Na+ excretion observed after cell-specific deletion of AT1 receptors from smooth muscle cells is associated with altered Na+ transporter abundance across epithelia in multiple nephron segments. These findings suggest a system of vascular-epithelial in the kidney, modulating the expression of Na+ transporters and contributing to the regulation of pressure natriuresis.NEW & NOTEWORTHY The use of drugs to block the renin-angiotensin system to reduce blood pressure is common. However, the precise mechanism for how these medications control blood pressure is incompletely understood. Here, we show that mice lacking angiotensin receptors specifically in smooth muscle cells lead to alternation in tubular transporter amount and function. Thus, demonstrating the importance of vascular-tubular cross talk in the control of blood pressure.

Impact of renin angiotensin system inhibitors on homocysteine levels and platelets reactivity in patients on dual antiplatelet therapy

BACKGROUND AND AIMS

Dual antiplatelet therapy (DAPT) and Renin-angiotensin system inhibitors (RASi) represent the cornerstone in the treatment of patients undergoing percutaneous coronary interventions (PCI), mainly after an acute ischemic event. However, high-on treatment residual platelet reactivity (HRPR), is not infrequent despite optimal medical treatment. Homocysteine (Hcy) is a metabolite of methionine catabolism linked to atherothrombosis. Recently, a potential crosstalk between RAS and Hcy has been suggested, potentially favouring platelet aggregation and cardiovascular disease.Therefore, we aimed to investigate the impact of RASi on Hcy levels and platelet aggregation in patients on DAPT after PCI.

METHODS AND RESULTS

Patients undergoing PCI on DAPT with ASA plus an ADP-antagonist (clopidogrel, ticagrelor or prasugrel), were included. RASi comprised angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB). Aggregation tests were performed by Multiple Electrode Aggregometry. We included 1210 patients, of whom 862 (71.2%) were on treatment with RASi. Overall, DAPT composition was ASA+clopidogrel in 566 (46.8%) patients, ASA+ticagrelor in 428 (35.4%) and ASA+prasugrel in 216 (17.9%). Median values of Hcy were higher in RASi patients (p = 0.006), who displayed a higher percentage of Hcy above the median value (52.4% vs. 44.8%, p = 0.019, adjustedOR [95%CI] = 1.40 [1.04-1.88], p = 0.027). No differences in HRPR rate were found according to RASi use for ASPI test (3.6% vs. 3.3%, p = 0.88) and ADP test (25.6% vs. 24.3%,p = 0.62; adjustedOR [95%CI] = 1.23 [0.89-1.70], p = 0.220) and according to ADP-antagonist type. A direct linear relationship was observed between platelet reactivity and Hcy in both patients receiving RASi and untreated ones, with higher values of platelet aggregation being observed in patients with Hcy above the median, independently from RASi administration and DAPT strategy.

CONCLUSION

In patients on DAPT after PCI, RASi treatment did not emerge as an independent predictor of HRPR. However, the levels of Hcy were significantly elevated in patients on RASi and related to higher values of platelet reactivity, independently from the DAPT strategy.

Angiotensin dependent and angiotensin independent protective effects of renin-b in H9c2 cells after anoxia

The renin-angiotensin system is known to regulate blood pressure as well as water- and electrolyte balance. An activated RAS is involved in the development of hypertension and hypertension-related organ damage. Thus, inhibitors of the RAS are protective and markedly increasing the life span of patients. In contrast, renin transcripts have been discovered encoding a cytoplasmatic renin isoform, termed renin-b, which is not harmful but may be even protective. Here we demonstrate that depletion of renin-b encoding transcripts by small interference RNA decreased ATP levels and increased basal necrosis as well as apoptosis rates. Furthermore, renin-b depletion potentiated the anoxia-induced increase of necrosis rates. Vice versa, overexpression of renin-b prevented the anoxia-induced increase of caspase-mediated apoptosis rates. Besides, cells overexpressing renin-b exhibited even reduced mitochondrial mediated apoptosis rates under anoxia, when compared with normoxic conditions, as indicated by Annexin V labeling. However, whereas the protective effect of renin-b on caspase-mediated apoptosis was completely blocked by the renin inhibitor CH732, the effect on mitochondrial-mediated apoptosis was not affected by CH732 at all. From these data we conclude that renin-b overexpression mediates cardioprotective effects under anoxia with respect to mitochondrial induced apoptosis angiotensin-independently, but with respect to caspase induced apoptosis likely in an angiotensin-dependent manner.

Preventing treatment failures in coronary artery disease: what can we learn from the biology of in-stent restenosis, vein graft failure, and internal thoracic arteries?

Coronary artery disease (CAD) remains one of the most important causes of morbidity and mortality worldwide, and the availability of percutaneous or surgical revascularization procedures significantly improves survival. However, both strategies are daunted by complications which limit long-term effectiveness. In-stent restenosis (ISR) is a major drawback for intracoronary stenting, while graft failure is the limiting factor for coronary artery bypass graft surgery (CABG), especially using veins. Conversely, internal thoracic artery (ITA) is known to maintain long-term patency in CABG. Understanding the biology and pathophysiology of ISR and vein graft failure (VGF) and mechanisms behind ITA resistance to failure is crucial to combat these complications in CAD treatment. This review intends to provide an overview of the biological mechanisms underlying stent and VGF and of the potential therapeutic strategy to prevent these complications. Interestingly, despite being different modalities of revascularization, mechanisms of failure of stent and saphenous vein grafts are very similar from the biological standpoint.

Effects of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers on all-cause mortality, cardiovascular death, and cardiovascular events among peritoneal dialysis patients: A protocol for systematic review

BACKGROUND

Based on the International Society for peritoneal dialysis (PD) recommendations, blockade of renin-angiotensin systems with an angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) improves residual kidney function in PD patients. However, the long-term effectiveness of ACEI/ARB use in PD patients has not been fully elucidated. We, therefore, intend to perform a systematic review and meta-analysis to summarize the effects of ACEI/ARB use on long-term mortality, cardiovascular outcomes, and adverse events among PD patients.

METHODS

This systematic review will include both randomized controlled trials and non-randomized studies in adult PD patients. We also plan to incorporate data from our cohort study in Thai PD population into this review. We will search PubMed, Medline, EMBASE, Cochrane Library, Web of Science, Scopus, CINAHL, and grey literature from inception to February 29, 2019, with no language restrictions. The process of study screening, selection, data extraction, risk of bias assessment, and grading the strength of evidence will be performed independently by a pair of reviewers. Any discrepancy will be resolved through a team discussion and/or consultation with the third reviewer. The pooled effects estimate and 95% confidence intervals will be estimated using DerSimonian-Laird random-effects models. Heterogeneity will be assessed by the Cochran Q test, I index and tau-squared statistics. The funnel plots along with the Begg and Egger test and trim and fill method will be performed to investigate any evidence of publication bias. Preplanned subgroup analyses and random-effects univariate meta-regressions will be performed to quantify the potential sources of heterogeneity based on studies- and patient-characteristics.

RESULTS

This will be the first systematic review and meta-analysis to summarize the long-term effectiveness of renin-angiotensin system inhibitors in PD populations.

CONCLUSION

In summary, this systematic review and meta-analysis will summarize the effectiveness of ACEI/ARB on long-term mortality, cardiovascular outcomes, and adverse events among adult PD patients by integrated all available evidences.

ETHICS AND DISSEMINATION

Based on the existing published data, an ethical approval is not required. The findings will be disseminated through scientific meetings and publications in peer-reviewed journals.PROSPERO registration number: CRD42019129492.

Non-secretory renin reduces oxidative stress and increases cardiomyoblast survival during glucose and oxygen deprivation

Although the renin-angiotensin system usually promotes oxidative stress and cell death, renin transcripts have been discovered, whose transcription product may be cardioprotective. These transcripts encode a non-secretory renin isoform that is localized in the cytosol and within mitochondria. Here we tested the hypotheses that cytosolic renin [ren(2-9)] expression promotes cell survival under hypoxia and glucose depletion by preserving the mitochondrial membrane potential (∆Ψ_m) and mitigating the accumulation of ROS. To simulate ischemic insults, we exposed H9c2 cells to glucose deprivation, anoxia or to combined oxygen-glucose deprivation (OGD) for 24 hours and determined renin expression. Furthermore, H9c2 cells transfected with the empty pIRES vector (pIRES cells) or ren(2-9) cDNA-containing vector [ren(2-9) cells] were analyzed for cell death, ∆Ψ_m, ATP levels, accumulation of ROS, and cytosolic Ca²⁺ content. In pIRES cells, expression of ren(1A-9) was stimulated under all three ischemia-related conditions. After OGD, the cells lost their ∆Ψ_m and exhibited enhanced ROS accumulation, increased cytosolic Ca²⁺ levels, decreased ATP levels as well as increased cell death. In contrast, ren(2-9) cells were markedly protected from these effects. Ren(2-9) appears to represent a protective response to OGD by reducing ROS generation and preserving mitochondrial functions. Therefore, it is a promising new target for the prevention of ischemia-induced myocardial damage.

Carbon-Coated Stent and the Role of the Kallikrein-Kinin System in Peripheral Angioplasty

OBJECTIVE

The purpose of this study was to investigate the clinical evolution of patients treated with carbon-coated stent, as well as its patency and the inflammatory response triggered by this process through the quantification of serum elements of the kallikrein-kinin system (KKS).

METHODS

This was a single-center prospective study with 27 patients with peripheral artery disease (PAD) who required percutaneous transluminal angioplasty and stenting of the iliacofemoropopliteal segment using carbon-coated stent grafts (carbostents). The blood concentrations of the total and kininogen fractions were evaluated using immunoenzymatic methods. Plasma kallikrein levels were assessed by the colorimetric method and tissue kallikrein levels were evaluated by the spectrophotometric method. The activity of kininase II was measured by -fluorometric analysis.

RESULTS

Of the 27 patients who completed the 6 months of the study (11 iliac territory, 16 femoropopliteal territory), only one experienced restenosis (3.7%) (femoropopliteal segment) and no patient had occlusion (96.3% of patency). In 1 year, four patients were lost to follow-up and all 23 patients evaluated maintained stent patency, except for the patient who had restenosis throughout the first 6 months. We report complete (100%) member salvage in 12 months of follow-up. The activity levels of high- and low-molecular-weight kininogens decreased significantly over time (before vs. 24 h, p < 0.01; before vs. 6 months, p < 0.001, and before vs. 24 h, p < 0.01; before vs. 6 months, p < 0.001; 24 h vs. 6 months, p < 0.001, respectively). Patients also had significantly lower levels of plasma and tissue kallikrein (before vs. 24 h, p < 0.001; before vs. 6 months, p < 0.001, and before vs. 24 h, p < 0.01; before vs. 6 months, p < 0.05, respectively). There was a significant increase in the enzymatic activity of kininase II at 24 h and after 6 months compared to the pre-treatment control (p < 0.001).

CONCLUSION

Our early experience shows that the use of carbon-coated stents in PAD appears to be safe, with low rates of early restenosis (3.7% in the first 6 months and 5% in the 12 months of follow-up). We concluded that KKS was involved in the inflammatory response caused by the placement of carbon-coated stents.

Chronic treatment with apelin, losartan and their combination reduces myocardial infarct size and improves cardiac mechanical function

The renin-angiotensin system (RAS) has a deleterious and apelin/APJ system has protective effect on the ischaemic heart. The collaboration between these systems in the pathophysiology of myocardial infarction is not clear. We determined the effect of chronic pretreatment with apelin, losartan and their combination on ischaemia-reperfusion (IR) injury in the isolated perfused rat heart and on the expression of apelin-13 receptor (APJ) and angiotensin type 1 receptor (AT1R) in the myocardium. During 5 days before the induction of IR, saline (vehicle), apelin-13 (Apl), F13A (apelin antagonist), losartan (Los, AT1R antagonist) and the combination of Apl and Los were administered intraperitoneally in rats. Ischaemia was induced by left anterior descending (LAD) artery occlusion for 30 minutes followed by reperfusion for 55 minutes in the Langendorff isolated heart perfusion system. Pretreatment with Apl, Los and the combination of Apl + Los significantly reduced infarct size by about 30, 33 and 48 percent respectively; and significantly improved the left ventricular function indices such as left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (LVEDP) and rate pressure product (RPP). IR increased AT1R protein level but it did not change APJ significantly. AT1R expression was reduced in groups treated with Apl, Los and Apl + Los. Findings showed that chronic pretreatment with apelin along with AT1R antagonist had more protective effects against IR injury. Combination therapy may diminish the risk of IR-induced heart damage, by reducing AT1R expression, in the heart of patients with coronary artery disease that are at the risk of MI and reperfusion injury.

An alternative renin isoform is cardioprotective by modulating mitochondrial metabolism

The renin‐angiotensin system promotes oxidative stress, apoptosis, necrosis, fibrosis, and thus heart failure. Secretory renin plays a central role in these processes, initiating the generation of angiotensins. Nevertheless, alternative renin transcripts exist, which code for a cytosolically localized renin isoform (cyto‐renin) that is cardioprotective. We tested the hypothesis that the protective effects are associated with a beneficial switch of metabolic and mitochondrial functions. To assess H9c2 cell mitochondrial parameters, we used the Seahorse XF analyser. Cardiac H9c2 cells overexpressing cyto‐renin exhibited enhanced nonmitochondrial oxygen consumption, lactate accumulation, and LDH activity, reflecting a switch to more aerobic glycolysis known as Warburg effect. Additionally, mitochondrial spare capacity and cell respiratory control ratio were enhanced, indicating an increased potential to tolerate stress conditions. Renin knockdown induced opposite effects on mitochondrial functions without influencing metabolic parameters. Thus, the protective effects of cyto‐renin are associated with an altered bioenergetic profile and an enhanced stress tolerance, which are favourable under ischaemic conditions. Therefore, cyto‐renin is a promising new target for the prevention of ischaemia‐induced myocardial damage.

Myocardial Infarction with Nonobstructive Coronary Arteries: The Importance of Achieving Secondary Prevention Targets

BACKGROUND

Approximately 5% to 10% of all patients with myocardial infarction have nonobstructive coronary arteries. Studies investigating the importance of follow-up and achievement of conventional secondary prevention targets in these patients are lacking.

METHODS

In this analysis from the Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies (SWEDEHEART) registry, we investigated 5830 patients with myocardial infarction with nonobstructive coronary arteries (group 1) and 54,637 patients with myocardial infarction with significant coronary artery disease (≥50% stenosis; group 2). Multivariable- and propensity score-adjusted statistics were used to assess the reduction in the 1-year risk of major adverse events associated with prespecified secondary preventive measures: participation in follow-up at 6 to 10 weeks after the hospitalization and achievement of secondary prevention targets (blood pressure and low-density lipoprotein cholesterol levels in the target ranges, nonsmoking, and participation in exercise training).

RESULTS

Patients in group 1 were less often followed up compared with patients in group 2 and less often achieved any of the secondary prevention targets. Participation in the 6- to 10-week follow-up was associated with a 3% to 20% risk reduction in group 1, similar as for group 2 according to interaction analysis. The improvement in outcome in group 1 was mainly mediated by achieving target range low-density lipoprotein cholesterol levels (24%-32% risk reduction) and, to a smaller extent, by participation in exercise training (10%-23% risk reduction).

CONCLUSIONS

Selected secondary preventive measures are associated with prognostic benefit in patients with myocardial infarction with nonobstructive coronary arteries, in particular achieving target range low-density lipoprotein cholesterol levels. Our results indicate that these patients should receive similar follow-up as myocardial infarction patients with significant coronary stenoses.

Curcumin and its demethoxy derivatives possess p300 HAT inhibitory activity and suppress hypertrophic responses in cardiomyocytes

The natural compound, curcumin (CUR), possesses several pharmacological properties, including p300-specific histone acetyltransferase (HAT) inhibitory activity. In our previous study, we demonstrated that CUR could prevent the development of cardiac hypertrophy by inhibiting p300-HAT activity. Other major curcuminoids isolated from Curcuma longa including demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC) are structural analogs of CUR. In present study, we first confirmed the effect of these three curcuminoid analogs on p300-HAT activity and cardiomyocyte hypertrophy. Our results showed that DMC and BDMC inhibited p300-HAT activity and cardiomyocyte hypertrophy to almost the same extent as CUR. As the three compounds have structural differences in methoxy groups at the 3-position of their phenol rings, our results suggest that these methoxy groups are not involved in the inhibitory effects on p300-HAT activity and cardiac hypertrophy. These findings provide useful insights into the structure-activity relationship and biological activity of curcuminoids for p300-HAT activity and cardiomyocyte hypertrophy.

Angiotensin II receptor blockers suppress the release of stromal cell-derived factor-1α from infarcted myocardium in patients with acute myocardial infarction

BACKGROUND

Although angiotensin II receptor blockers (ARBs) have been shown to have anti-inflammatory effects on infarcted myocardium in experimental models, little is known in humans. Stromal cell-derived factor-1α (SDF-1α), a pro-inflammatory chemokine, is released from infarcted tissue in patients with acute myocardial infarction (AMI). This study examined whether ARBs suppress SDF-1α production in the infarcted lesion in patients with AMI.

METHODS

SDF-1α levels were measured by enzyme-linked immunosorbent assays in plasma obtained from the aortic root (AO) and the anterior interventricular vein (AIV) in 50 patients with an anterior AMI. Measurement of SDF-1α levels and left ventriculography were repeated at discharge and 6 months after AMI. Patients were divided into 2 groups according to treatment with ARBs, which were administered at the discretion of the attending physician after admission.

RESULTS

The AIV-AO gradient of SDF-1α, reflecting SDF-1α release from the infarcted myocardial region, decreased between the time of discharge and 6 months after AMI in patients taking an ARB. In contrast, the SDF-1α transcardiac gradient did not change in patients not taking an ARB. Among the clinical parameters tested, only the use of ARBs was significantly associated with percent changes in the SDF-1α transcardiac gradient from the time of discharge to 6 months after AMI in a linear regression analysis (r=-0.31, p=0.03). The SDF-1α transcardiac gradient 6 months after AMI was inversely correlated with the percent change in left ventricular (LV) ejection fraction (r=-0.52, p<0.01) and positively correlated with the percent change in LV end-diastolic volume index (r=0.57, p<0.01) and LV end-systolic volume index (r=0.54, p<0.01) during 6 months after AMI.

CONCLUSIONS

ARB treatment suppressed SDF-1α release from the infarcted myocardial region, which was associated with improvement in LV dysfunction and adverse remodeling in AMI survivors.

Recent Progress in Vascular Aging: Mechanisms and Its Role in Age-related Diseases

As with many age-related diseases including vascular dysfunction, age is considered an independent and crucial risk factor. Complicated alterations of structure and function in the vasculature are linked with aging hence, understanding the underlying mechanisms of age-induced vascular pathophysiological changes holds possibilities for developing clinical diagnostic methods and new therapeutic strategies. Here, we discuss the underlying molecular mediators that could be involved in vascular aging, e.g., the renin-angiotensin system and pro-inflammatory factors, metalloproteinases, calpain-1, monocyte chemoattractant protein-1 (MCP-1) and TGFβ-1 as well as the potential roles of testosterone and estrogen. We then relate all of these to clinical manifestations such as vascular dementia and stroke in addition to reviewing the existing clinical measurements and potential interventions for age-related vascular dysfunction.

Medical Therapy for Secondary Prevention and Long-Term Outcome in Patients With Myocardial Infarction With Nonobstructive Coronary Artery Disease

BACKGROUND

Myocardial infarction with nonobstructive coronary arteries (MINOCA) occurs in 5% to 10% of all patients with myocardial infarction. Clinical trials of secondary prevention treatment in MINOCA patients are lacking. Therefore, the aim of this study was to examine the associations between treatment with statins, renin-angiotensin system blockers, β-blockers, dual antiplatelet therapy, and long-term cardiovascular events.

METHODS

This is an observational study of MINOCA patients recorded in the SWEDEHEART registry (the Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapy) between July 2003 and June 2013 and followed until December 2013 for outcome events in the Swedish Cause of Death Register and National Patient Register. Of 199 162 myocardial infarction admissions, 9466 consecutive unique patients with MINOCA were identified. Among those, the 9136 patients surviving the first 30 days after discharge constituted the study population. Mean age was 65.3 years, and 61% were women. No patient was lost to follow-up. A stratified propensity score analysis was performed to match treated and untreated groups. The association between treatment and outcome was estimated by comparing between treated and untreated groups by using Cox proportional hazards models. The exposures were treatment at discharge with statins, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, and dual antiplatelet therapy. The primary end point was major adverse cardiac events defined as all-cause mortality, hospitalization for myocardial infarction, ischemic stroke, and heart failure.

RESULTS

At discharge, 84.5%, 64.1%, 83.4%, and 66.4% of the patients were on statins, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, and dual antiplatelet therapy, respectively. During the follow-up of a mean of 4.1 years, 2183 (23.9%) patients experienced a major adverse cardiac event. The hazard ratios (95% confidence intervals) for major adverse cardiac events were 0.77 (0.68-0.87), 0.82 (0.73-0.93), and 0.86 (0.74-1.01) in patients on statins, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and β-blockers, respectively. For patients on dual antiplatelet therapy followed for 1 year, the hazard ratio was 0.90 (0.74-1.08).

CONCLUSIONS

The results indicate long-term beneficial effects of treatment with statins and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers on outcome in patients with MINOCA, a trend toward a positive effect of β-blocker treatment, and a neutral effect of dual antiplatelet therapy. Properly powered randomized clinical trials to confirm these results are warranted.

Olmesartan-associated enteropathy: new insights on the natural history? Report of two cases

INTRODUCTION

The association between olmesartan and an enteropathy histologically indistinguishable from untreated celiac disease has recently been described. However, pathogenetic mechanisms leading to villous atrophy, prevalence, natural history and genetic background of this condition have not yet been defined.

PATIENTS

We describe here two cases of olmesartan-associated enteropathy and discuss some aspects of the natural history of this condition.

RESULTS

In both patients, an infectious episode seems to have triggered the severe malabsorption syndrome which led them to hospitalization. High titer positive antinuclear antibodies with homogeneous pattern were found.

CONCLUSIONS

Our reports add to a growing body of evidence suggesting that olmesartan-associated enteropathy should be considered in the presence of villous atrophy and negative celiac serology and in the diagnostic algorithm of non-responsive celiac disease.

Effects of telmisartan and pioglitazone on high fructose induced metabolic syndrome in rats

Metabolic syndrome (MS) is a cluster of hypertension, insulin resistance, dyslipidaemia, and hyperuricemia. This study was designed to assess the effect of telmisartan and pioglitazone on high fructose induced MS. Thirty-five male albino rats were classified into 5 groups: A, normal diet; B, high-fructose diet (HFD) subdivided into B1 (HFD only), B2 (telmisartan, 5 mg/kg), B3 (pioglitazone, 10 mg/kg), and B4 (telmisartan + pioglitazone). Administration of the drugs was started after the rats had been on HFD for 4 weeks and continued for 4 weeks. Body mass (BM), blood pressure (BP), uric acid (UA), total cholesterol, triglycerides (TG), high-density lipoprotein (HDL-c), low-density lipoprotein (LDL-c), blood urea nitrogen (BUN), creatinine, and nitric oxide (NO) were measured and the levels of fasting glucose and fasting insulin were estimated. Compared with group B1, telmisartan treatment significantly decreased BP, BM, serum glucose, insulin, UA, urea, cholesterol, TGA, and LDL and significantly increased HDL, whereas pioglitazone treatment significantly decreased BP, serum glucose, insulin, UA, urea, creatinine, cholesterol, TGA, and LDL and significantly increased HDL. Co-administration of pioglitazone + telmisartan significantly decreased insulin, urea, and creatinine compared with telmisartan alone. Combined telmisartan + pioglitazone allowed better control of BP, hyperglycaemia, insulin resistance, and the amelioration of BM increase that may be associated with pioglitazone treatment.

Endothelial progenitor cells (EPCs) in ageing and age-related diseases: How currently available treatment modalities affect EPC biology, atherosclerosis, and cardiovascular outcomes

Endothelial progenitor cells (EPCs) are mononuclear cells that circulate in the blood and are derived from different tissues, expressing cell surface markers that are similar to mature endothelial cells. The discovery of EPCs has lead to new insights in vascular repair and atherosclerosis and also a new theory for ageing. EPCs from the bone marrow and some other organs aid in vascular repair by migrating to distant vessels where they differentiate into mature endothelial cells and replace old and injured endothelial cells. The ability of EPCs to repair vascular damage depends on their number and functionality. Currently marketed drugs used in a variety of diseases can modulate these characteristics. In this review, the effect of currently available treatment options for cardiovascular and metabolic disorders on EPC biology will be discussed. The various EPC-based therapies that will be discussed include lipid-lowering agents, antihypertensive agents, antidiabetic drugs, phosphodiesteraze inhibitors, hormones, as well as EPC capturing stents.

Myocardial Production of Plasminogen Activator Inhibitor-1 is Associated with Coronary Endothelial and Ventricular Dysfunction after Acute Myocardial Infarction

AIM

Although plasminogen activator inhibitor-1 (PAI-1) is abundantly expressed in infarcted myocardium, the pathogenic role of myocardial PAI-1 remains unknown. This study examined whether PAI-1 in the infarcted lesion contributes to coronary endothelial dysfunction and left ventricular (LV) dysfunction in patients with acute myocardial infarction (AMI).

METHODS

Plasma levels of PAI-1 activity and tissue-plasminogen activator (tPA) antigen were measured 2 weeks and 6 months after MI by ELISA in plasma obtained from the aortic root (AO) and anterior interventricular vein (AIV) in 28 patients with a first AMI due to occlusion of the left anterior descending coronary artery (LAD). Coronary blood flow responses in LAD to intracoronary infusion of acetylcholine (ACh) and left ventriculography were measured at the same time points: 2 weeks and 6 months after MI.

RESULTS

The trans-myocardial gradient of PAI-1 from AO to AIV, reflecting production/release of PAI-1 in the infarcted lesion, was inversely correlated with the coronary blood flow response to ACh 6 months after MI (r=-0.43, p=0.02) and with the percentage change in LV regional motion in the LAD territory from 2 weeks to 6 months after MI (r=-0.38, p=0.04). The trans-myocardial gradient of tPA level showed no significant correlations.

CONCLUSIONS

PAI-1 produced in the infarcted myocardium and released into the coronary circulation is associated with endothelial dysfunction in resistance vessels of the infarct-related coronary arteries and with progressive dysfunction of the infarcted region of the left ventricle in AMI survivors.

Angiotensin Receptor Blockers Decrease the Risk of Major Adverse Cardiovascular Events in Patients with End-Stage Renal Disease on Maintenance Dialysis: A Nationwide Matched-Cohort Study

Background

Major adverse cardiovascular events (MACE) cause the leading cause of morbidity and mortality in patients with end-stage renal disease (ESRD) on maintenance Hemodialysis (HD) or peritoneal dialysis (PD). Many randomized-controlled trials (RCTs) have proved that angiotensin receptor blockers (ARBs) can reduce the risk of MACE in the people with normal or impaired kidney function without dialysis. This study seeks to clarify whether ARBs therapy could also attenuate this risk in patients with ESRD on maintenance dialysis.

Materials and Methods

The National Health Research Institute provided a database of one million random subjects for the study. A random sample was taken of 1800 patients ≥18 years y/o with ESRD on dialysis without a history of MACE and use of ARBs within 6-months prior to enrollment. Cox proportional hazard regression analysis was used to identify the risk factors and compute the hazard ratios accompanying 95% confidence intervals.

Results

In these 1800 patients, 1061 had never used ARBs, while 224 had used them for 1–90 days, and 515 had used them for more than 90 days. We found that ARBs significantly decrease the incidences of acute myocardial infarctions (AMI), coronary artery diseases (CAD) requiring coronary stent or percutaneous transluminal coronary angioplasty (PTCA), peripheral artery disease (PAD) requiring percutaneous transluminal angioplasty (PTA), and acute stroke. Cumulative prescription days of ARBs beyond 365–760 days or more were found to be negatively correlated with incidence of MACEs. For patients with dual comorbidity (i.e., mellitus and hyperlipidemia), 91–365 cumulative prescription days might also attenuate the risk.

Conclusions

For patients on maintenance dialysis, the use of ARBs could significantly attenuate the risk of major cardiovascular events: AMI, acute stroke, and PAD requiring PTA.

Possible prevention of dialysis-requiring congestive heart failure by angiotensin-II receptor blockers in non-dialysis Japanese patients with Stage 5 chronic kidney disease

BACKGROUND

Preventive medications for dialysis-requiring congestive heart failure (CHF) in non-dialysis Japanese patients with Stage 5 chronic kidney disease (CKD) are unknown. Our aim was to explore which CKD medication was associated with a reduced prevalence of dialysis-requiring CHF in non-dialysis Japanese patients with Stage 5 CKD.

METHODS

The present multicenter, retrospective, cross-sectional study examined the association between CKD medications and the prevalence of dialysis-requiring CHF in non-dialysis Japanese patients with Stage 5 CKD.

RESULTS

There were 1536 Japanese Stage 5 CKD patients who satisfied our inclusion criteria. We had 309 (20.1%) patients whom had developed dialysis-requiring CHF and 940 patients (60.8%) whom had been using angiotensin-II receptor blockers (ARBs) before initiating dialysis. In our multivariate analysis, only ARB use was significantly associated with a lower risk of CHF (Odds ratio (OR): 0.680, 95% confidence interval (CI): 0.516-0.897; p = 0.0064), of the CKD treatments examined in this study.

CONCLUSIONS

We found that ARB use during the pre-dialysis period is associated with a lower prevalence of CHF in the non-dialysis Japanese patients with Stage 5 CKD, suggesting a possible prevention of dialysis-requiring CHF by ARBs, in non-dialysis Japanese patients with Stage 5 CKD.

Pentoxifylline Decreases Dialysis Risk in Patients With Advanced Chronic Kidney Disease

Few studies evaluated the effects of pentoxifylline on hard endpoints in patients with predialysis stage 5 chronic kidney disease (CKD). Thus, we tried to explore the effects of pentoxifylline and its interaction with renin-angiotensin-aldosterone system (RAAS) blockade on the development of endstage renal disease (ESRD) and mortality. This nationwide cohort study retrospectively included patients who had a serum creatinine level of >6 mg/dL and received erythropoiesis-stimulating agents (ESAs) between 2000 and 2010. We analyzed 7,366 pentoxifylline users and 7,366 propensity score-matched nonusers. Using Cox proportional hazard models, pentoxifylline reduced the risks of ESRD and the composite renal outcome but not that of mortality. In terms of the risks of developing ESRD, pentoxifylline alone exerted a comparable beneficial effect to combined therapy with an RAAS inhibitor and greater renoprotection than RAAS inhibitor monotherapy. This study suggests pentoxifylline is efficacious in slowing progression to ESRD in patients with predialysis stage 5 CKD.

Neuropeptides: metabolism to bioactive fragments and the pharmacology of their receptors

The proteolytic processing of neuropeptides has an important regulatory function and the peptide fragments resulting from the enzymatic degradation often exert essential physiological roles. The proteolytic processing generates, not only biologically inactive fragments, but also bioactive fragments that modulate or even counteract the response of their parent peptides. Frequently, these peptide fragments interact with receptors that are not recognized by the parent peptides. This review discusses tachykinins, opioid peptides, angiotensins, bradykinins, and neuropeptide Y that are present in the central nervous system and their processing to bioactive degradation products. These well-known neuropeptide systems have been selected since they provide illustrative examples that proteolytic degradation of parent peptides can lead to bioactive metabolites with different biological activities as compared to their parent peptides. For example, substance P, dynorphin A, angiotensin I and II, bradykinin, and neuropeptide Y are all degraded to bioactive fragments with pharmacological profiles that differ considerably from those of the parent peptides. The review discusses a selection of the large number of drug-like molecules that act as agonists or antagonists at receptors of neuropeptides. It focuses in particular on the efforts to identify selective drug-like agonists and antagonists mimicking the effects of the endogenous peptide fragments formed. As exemplified in this review, many common neuropeptides are degraded to a variety of smaller fragments but many of the fragments generated have not yet been examined in detail with regard to their potential biological activities. Since these bioactive fragments contain a small number of amino acid residues, they provide an ideal starting point for the development of drug-like substances with ability to mimic the effects of the degradation products. Thus, these substances could provide a rich source of new pharmaceuticals. However, as discussed herein relatively few examples have so far been disclosed of successful attempts to create bioavailable, drug-like agonists or antagonists, starting from the structure of endogenous peptide fragments and applying procedures relying on stepwise manipulations and simplifications of the peptide structures.

Perspectives for angiotensin profiling with liquid chromatography/mass spectrometry to evaluate ACE/ACE2 balance in endothelial dysfunction and vascular pathologies

Vascular injury, characterized by endothelial dysfunction, inflammation, structural remodeling, thrombosis and calcification leads to cardiovascular diseases. Angiotensin (Ang) II (1-8) - synthesized mainly by angiotensin converting enzyme (ACE) is the best characterized mediator of the renin-angiotensin system (RAS). This peptide initially identified by its vasoactive properties was found to play a major role in vascular response to insult. However, recent discovery of angiotensin converting enzyme 2 (ACE2) that produces vasoprotective Ang-(1-7) peptide highlighted complexity of the system and suggested that balance between ACE/Ang II and ACE2/Ang-(1-7) is fundamental in maintaining vascular homeostasis and its disorders are associated with cardiovascular pathology. There is therefore a need to develop methods for comprehensive analysis of biologically active Ang peptides and their metabolites of ACE/Ang II and ACE2/Ang-(1-7) axes. Liquid chromatography/mass spectrometry (LC/MS) is an analytical technique that offers potential for specific, simultaneous analysis of Ang peptides. With sensitivity added by application of preconcentration nanochromatography reaching picomolar concentrations, practically all Ang peptides identified so far could be quantified in biological samples. Ang profiling is important not only for understanding their physiological or pathological role but could also serve as an early diagnostic biomarker of endothelial dysfunction and cardiovascular pathology. It could also be used for monitoring the efficacy of the RAS-targeted therapies. Although, the methodology requires further improvements to adopt it for routine application, Ang peptide profiling with targeted LC/MS analysis might assess functional balance between ACE/Ang II and ACE2/Ang-(1-7) axes, facilitate our understanding of the cardiovascular pathology and enhance biomarker portfolio in cardiovascular diseases.

Development of a sensitive, accurate and robust liquid chromatography/mass spectrometric method for profiling of angiotensin peptides in plasma and its application for atherosclerotic mice

Quantification of angiotensin (Ang) peptides in biological matrices is a challenge due to their low picomolar (pM) concentration and poor analytical performance of current methods. This work aimed to select an optimal strategy for liquid chromatography/mass spectrometry (LC/MS) quantification of major angiotensins in plasma of wild type and atherosclerotic mice. Optimal LC/MS set-up for Ang quantification was chosen, based on analytical performance, from: nanoflow/orbitrap, nanoflow/triple quadrupole and preconcentration nanoflow/triple quadrupole. The best LC/MS configuration (preconcentration nanoflow/triple quadrupole) was validated and used for measurement of angiotensins (Ang I, II, III, IV and (1-7)) in plasma of 6-month-old atherosclerotic apolipoprotein E/LDL receptor double knock-outs (ApoE/LDLR (--/--)) and wild type C57BL/6J (WT) mice. The method established for Ang quantification was selective, accurate and highly sensitive with LLOQ of 5pgmL(-1). The peak area intra-day precisions for Ang II and Ang-(1-7) were in the range 3.0-5.1 and 3.5-5.8, respectively, with corresponding accuracy of 95.4-103.5% and 95.6-106.3%. Plasma angiotensin profile was substantially modified in ApoE/LDLR knock-out mice with increase in concentration of Ang II from 37.6±21.3pgmL(-1) in WT to 200.2±47.6pgmL(-1). Concentrations of Ang I, III and IV were also increased 3-10 fold in ApoE/LDLR (--/--) mice while that of Ang-(1-7) was unchanged. We conclude that the method developed could be effectively used for accurate, comprehensive profiling of angiotensin peptides in mouse plasma. We identified substantial changes in renin-angiotensin system in a genetic mouse model of atherosclerosis consistent with the overactivation of angiotensin converting enzyme (ACE) and the impairment of ACE2.

Simultaneous quantification of related substances of perindopril tert-butylamine using a novel stability indicating liquid chromatographic method

A novel stability indicating gradient reverse-phased high-performance liquid chromatographic method has been developed for the quantification of impurities of perindopril tert-butylamine (PER) in pharmaceutical dosage form. Separation of the active substance and its known (Impurities B, C, D, E, F) and unknown impurities was achieved on a BDS Hypersil C18 column (250 mm × 4.6 mm, 5 µm), thermostated at 70°C, using a mobile phase comprised of aqueous solution of sodium 1-heptanesulfonate adjusted to pH 2 with perchloric acid and acetonitrile. The flow rate was maintained at 1.5 mL min(-1), injection volume of 20 µL was utilized and detection of analytes was performed at 215 nm. The developed method was validated in accordance with current ICH Guidelines for all suggested parameters, including forced degradation studies and proved to be linear, accurate, precise and suitable for the impurity testing of PER, being subsequently applied during on-going stability studies of a newly developed generic formulation.