Mechanisms by which angiotensin-converting enzyme inhibitors prevent diabetes and cardiovascular disease

Clinical parameters of death and heart failure hospitalization in biventricular systolic dysfunction assessed via cardiac magnetic resonance

AIMS

While factors associated with adverse events are well elucidated in setting of isolated left ventricular dysfunction, clinical and imaging-based prognosticators of adverse outcomes are lacking in context of biventricular dysfunction. The purpose of this study was to establish role of clinical variables in prognosis of biventricular heart failure (HF), as assessed by cardiac magnetic resonance imaging.

METHODS

Study cohort consisted of 840 patients enrolled in DERIVATE registry with coexisting CMR-derived right ventricular (RV) and left ventricular (LV) dysfunction, as defined by RV and LV ejection fractions ≤45 % and ≤ 50 %, respectively. The primary objective was to identify factors associated with adverse long-term outcomes, defined as composite of all-cause death and HF hospitalizations (DHFH). Kaplan-Meir curves were plotted for survival analysis. Cox proportional hazard models were constructed to estimate adjusted hazard ratios (aHRs) and associated 95 % confidence intervals for clinical variables and their correlation with adverse events.

RESULTS

Mean age was 61.0 years; 83.1 % were male, 26.6 % had diabetes mellitus (DM), and 45.9 % had non-ischemic cardiomyopathy. At median follow-up of 2 years, DHFH occurred in 32.5 % of the cohort. Kaplan-Meir analysis showed higher rate of DHFH in patients with DM (35.2 % vs. 22.6 %, p < 0.001). Multivariate Cox regression analysis showed that DM was independently associated with DHFH (aHR 1.61 [95 % CI: 1.15-2.25]; p = 0.003). Importantly, ACE-inhibitor/ARB usage in patients with DM was associated with significant reduction in DHFH (aHR 0.53 [95 % CI: 0.31-0.90]; p = 0.02).

CONCLUSION

In patients with biventricular HF, DM was a strong predictor of DHFH, with ACE-inhibitor/ARB usage having cardioprotective effect.

Imperatorin's Effect on Myocardial Infarction Based on Network Pharmacology and Molecular Docking

Purpose: Myocardial infarction (MI), a severe cardiovascular disease, is the result of insufficient blood supply to the myocardium. Despite the improvements of conventional therapies, new approaches are needed to improve the outcome post-MI. Imperatorin is a natural compound with multiple pharmacological properties and potential cardioprotective effects. Therefore, this work investigated imperatorin's therapeutic effects and its mechanism of action in an MI mouse model. Methods: Network pharmacology, molecular docking, and experimental validation were performed for exploring the pharmacokinetic properties, therapeutic effects, and molecular targets of imperatorin in MI. Permanent ligation of the left anterior descending artery was performed in male C57BL/6 mice to induce MI before treatment with imperatorin once per day for 1 week. Echocardiography, heart histology, RNA sequencing, and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) as well as western blotting were carried out for evaluating cardiac function and structure, as well as gene and protein expression. Results: Imperatorin significantly improved cardiac function, preserved cardiac structure, attenuated cardiac remodeling and fibrosis, and reduced cardiomyocyte apoptosis in MI mice. Eight differentially expressed genes overlapping with key target genes were found, two upregulated and six downregulated. A key target in signaling pathways associated with imperatorin effect in MI was angiotensin-converting enzyme (ACE). Imperatorin inhibited ACE-angiotensin II (Ang II)-angiotensin II Type 1 receptor (AT1R) axis in MI mice. Conclusion: Imperatorin attenuated MI by inhibiting the ACE-Ang II-AT1R axis. Thus, imperatorin might be considered a potential therapeutic agent to cure MI.

A Narrative Review of Diabetic Macroangiopathy: From Molecular Mechanism to Therapeutic Approaches

Diabetic macroangiopathy, a prevalent and severe complication of diabetes mellitus, significantly contributes to the increased morbidity and mortality rates among affected individuals. This complex disorder involves multifaceted molecular mechanisms that lead to the dysfunction and damage of large blood vessels, including atherosclerosis (AS) and peripheral arterial disease. Understanding the intricate pathways underlying the development and progression of diabetic macroangiopathy is crucial for the development of effective therapeutic interventions. This review aims to shed light on the molecular mechanism implicated in the pathogenesis of diabetic macroangiopathy. We delve into the intricate interplay of chronic inflammation, oxidative stress, endothelial dysfunction, and dysregulated angiogenesis, all of which contribute to the vascular complications observed in this disorder. By exploring the molecular mechanism involved in the disease we provide insight into potential therapeutic targets and strategies. Moreover, we discuss the current therapeutic approaches used for treating diabetic macroangiopathy, including glycemic control, lipid-lowering agents, and vascular interventions.

The role of captopril in leukotriene deficient type 1 diabetic mice

T1D can be associated with metabolic disorders and several impaired pathways, including insulin signaling, and development of insulin resistance through the renin-angiotensin system (RAS). The main precursor of RAS is angiotensinogen (Agt) and this system is often linked to autophagy dysregulation. Dysregulated autophagy has been described in T1D and linked to impairments in both glucose metabolism, and leukotrienes (LTs) production. Here, we have investigated the role of RAS and LTs in both muscle and liver from T1D mice, and its effects on insulin and autophagy pathways. We have chemically induced T1D in 129sve and 129sve 5LO-/- mice (lacking LTs) with streptozotocin (STZ). To further inhibit ACE activity, mice were treated with captopril (Cap). In muscle of T1D mice, treatment with Cap increased the expression of RAS (angiotensinogen and angiotensin II receptor), insulin signaling, and autophagy markers, regardless of the genotype. In the liver of T1D mice, the treatment with Cap increased the expression of RAS and insulin signaling markers, mostly when LTs were absent. 5LO-/- T1D mice showed increased insulin sensitivity, and decreased NEFA, after the Cap treatment. Cap treatment impacted both insulin signaling and autophagy pathways at the mRNA levels in muscle and liver, indicating the potential role of ACE inhibition on insulin sensitivity and autophagy in T1D.

Angiotensin Regulation of Vascular Homeostasis: Exploring the Role of ROS and RAS Blockers

Extensive research has been conducted to elucidate and substantiate the crucial role of the Renin-Angiotensin System (RAS) in the pathogenesis of hypertension, cardiovascular disorders, and renal diseases. Furthermore, the role of oxidative stress in maintaining vascular balance has been well established. It has been observed that many of the cellular effects induced by Angiotensin II (Ang II) are facilitated by reactive oxygen species (ROS) produced by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. In this paper, we present a comprehensive overview of the role of ROS in the physiology of human blood vessels, specifically focusing on its interaction with RAS. Moreover, we delve into the mechanisms by which clinical interventions targeting RAS influence redox signaling in the vascular wall.

The importance of graph databases and graph learning for clinical applications

The increasing amount and complexity of clinical data require an appropriate way of storing and analyzing those data. Traditional approaches use a tabular structure (relational databases) for storing data and thereby complicate storing and retrieving interlinked data from the clinical domain. Graph databases provide a great solution for this by storing data in a graph as nodes (vertices) that are connected by edges (links). The underlying graph structure can be used for the subsequent data analysis (graph learning). Graph learning consists of two parts: graph representation learning and graph analytics. Graph representation learning aims to reduce high-dimensional input graphs to low-dimensional representations. Then, graph analytics uses the obtained representations for analytical tasks like visualization, classification, link prediction and clustering which can be used to solve domain-specific problems. In this survey, we review current state-of-the-art graph database management systems, graph learning algorithms and a variety of graph applications in the clinical domain. Furthermore, we provide a comprehensive use case for a clearer understanding of complex graph learning algorithms. Graphical abstract.

The Effect of Treatment With Aminoguanidine, an Advanced Glycation End Product Inhibitor, on Streptozotocin-Induced Diabetic Rats and Its Effects on Physiological and Renal Functions

BACKGROUND/AIM

Diabetes is a multifactorial syndrome that affects the functioning of the renin-angiotensin system (RAS). The role of advanced glycation end products (AGEs) in diabetes is well known. In the present study, we hypothesized that the prevention of AGE accumulation or abrogation of AGE synthesis using an AGE inhibitor, aminoguanidine (AG), in streptozotocin (STZ)-induced diabetic animal models would affect the progression of diabetes and its related complications. We determined the effects of aminoguanidine (AG), an AGE inhibitor, in STZ-induced diabetic rats by determining various indices of RAS and renal functions. Additionally, we also investigated the effect of the drug, AG, on various hemodynamic and physiological functions in the body of the animals.

METHODS

Male Sprague Dawley rats weighing 200-250 g were assigned to four groups (n = 4-6): Vehicle, Vehicle+AG, STZ-induced, and STZ-induced+AG rats. Type 1 diabetes was induced by a single intraperitoneal (IP) injection of streptozotocin (55 mg/kg) dissolved in sodium citrate buffer. The control groups (Vehicle) were injected with buffer. The blood glucose levels were measured after 48 hours, and animals with blood glucose levels > 300 mg/dL were included in the study. Blood glucose levels in the vehicle rats were also determined to ensure non-diabetic conditions. After confirmation, AG was administrated at a dose of 1 g/L in drinking water for two weeks. Urine was collected to measure the glomerular filtration rate (GFR), and the immune reactivity for AT1 and AT2 proteins was analyzed by immunoblotting. Data were expressed as mean ± standard error of the mean (SEM), and a p-value < 0.05 was considered statistically significant.

RESULTS

Diabetic rats had a significant drop in body weight, accompanied by increased food and water consumption. The diabetic rats exhibited significantly increased urine flow and GFR. These phenotypes were significantly or considerately reversed by AG treatment in the STZ+AG-treated diabetic rats. Aminoguanidine prevented the increase in blood sugar levels compared to STZ-induced diabetic rats alone (295.9 ± 50.69 versus 462.3 ± 18.6 mg/dL (p < 0.05)). However, it did not affect the glomerular filtration rate (GFR) and glomerular damage, as assessed by the renal histopathological studies. The STZ-induced diabetic rats had an increased sodium excretion (3.24 ± 0.40 mmol) and significantly increased expression of the AT2 receptor and that of the AT1 receptor, which was slightly reversed by the treatment with AG. Treatment with AG decreased sodium excretion (2.12 ± 0.63, as compared to the diabetic rats). These rats also had modestly decreased expression of the AT2 receptor (0.99 ± 0.07 versus 1.12 ± 0.08, as compared to the STZ-induced diabetic rats), while the AT1 receptors showed a slight increase in the STZ+AG-treated rats compared to the STZ-induced diabetic rats (1.1 ± 0.19 versus 1.08 ± 0.12).

CONCLUSION

This study highlights the action of the drug AG in not exacerbating any damage in diabetic rats. Employing AG as a pharmacological intervention to prevent an increase in blood sugar adds a new dimension to controlling increased blood sugar and preventing diabetic complications. The employability and pharmacological intervention of the drug AG, in diabetes, therefore, need a renewed and further investigation.

Disparate Clinical Characteristics and Prognosis of HFpEF versus HFrEF Phenotype of Diabetic Cardiomyopathy

AIMS

Diabetic cardiomyopathy (DCM) is an ill-defined entity. This study aims to explore the clinical characteristics and prognosis of diabetic patients that disparately develop heart failure (HF) with preserved ejection fraction (HFpEF) other than HF with reduced ejection fraction (HFrEF).

PATIENTS AND METHODS

A total of 911 patients diagnosed with diabetes mellitus were identified in the ChiHFpEF cohort (NCT05278026). DCM was defined as diabetic patients diagnosed with HF, absent from flow obstructive coronary artery disease (CAD), uncontrolled refractory hypertension and hemodynamics significant heart valvular diseases, arrhythmia and congenital heart diseases. The primary endpoint was a composite of all-cause death and rehospitalization due to HF.

RESULTS

As compared to DCM-HFrEF patients, DCM-HFpEF patients had a longer duration of diabetes, were older and more noticeable in hypertension and non-obstructive CAD. After a median follow-up of 45.5 months, survival analysis showed that DCM-HFpEF patients had a better composite endpoint. Cox regression implicated that non-obstructive CAD was a negative (HR 0.101, 95% CI 0.028-0.373, p = 0.001) predictor for the composite endpoint of DCM-HFrEF patients. Age was a positive predictor for the composite endpoint of DCM-HFpEF patients (HR 1.044, 95% CI 1.007-1.082, p = 0.018).

CONCLUSION

DCM-HFpEF is a disparate entity from DCM-HFrEF. Additional phenomic studies are needed to explore the molecular mechanisms and develop targeted therapies.

Endocrine manifestations of chronic kidney disease and their evolving management: A systematic review

BACKGROUND

Chronic Kidney Disease (CKD) shows a wide range of renal abnormalities including the excretory, metabolic, endocrine, and homeostatic function of the kidney. The prognostic impact of the 'endocrine manifestations' which are often overlooked by clinicians cannot be overstated.

METHODS AND OBJECTIVES

A systematic review was attempted to provide a comprehensive overview of all endocrine abnormalities of CKD and their evolving principles of management, searching databases of PubMed, Embase, and Scopus and covering the literature between 2002 and 2022.

RESULTS

The endocrine derangements in CKD can be attributed to a myriad of pathologic processes, in particular decreased clearance, impaired endogenous hormone production, uremia-induced cellular dysfunction, and activation of systemic inflammatory pathways. The major disorders include anemia, hyperprolactinemia, insulin resistance, reproductive hormone deficiency, thyroid hormone deficiency, and serum FGF (Fibroblast Growth Factor) alteration. Long-term effects of CKD also include malnutrition and increased cardiovascular risk. The recent times have unveiled their detailed pathogenesis and have seen an evolution in the principles of management which necessitates a revision of current guidelines.

CONCLUSION

Increased advertence regarding the pathology, impact, and management of these endocrine derangements can help in reducing morbidity as well as mortality in the CKD patients by allowing prompt individualized treatment. Moreover, with timely and appropriate intervention, a long-term reduction in complications, as well as an enhanced quality of life, can be achieved in patients with CKD.

Diabetes in COVID-19 patients: challenges and possible management strategies

Background

The recent pandemic of coronavirus disease 19 (COVID-19) has been causing intense stress among the global population. In the case of hospitalized and ICU-admitted COVID-19 patients with comorbidities, it has been observed that a major portion of them are diabetic. Therefore, researchers had indicated a link between diabetes mellitus (DM) and COVID-19. Furthermore, DM is a potential risk factor for the severity of COVID-19 cases. Thus, in this study, the correlation existing between diabetic patients and COVID-19 was summarized.

Main body of the abstract

Diabetic patients have a weaker immune system, less viral clearance rate, malfunctions of metabolic activity due to their high blood glucose level, and other associated problems. This does not increase the susceptibility for the patients to be infected with COVID-19. However, the severity of COVID-19 can worsen due to the comorbidity of DM.

Short conclusion

Proper management, appropriate use of drugs that do not increase the ACE2 expression, lowering blood glucose level, decreasing the susceptibility of SARS-CoV-2, and maintaining a healthy lifestyle could be effective.

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.

Nutritional Composition and Health Benefits of Various Botanical Types of Melon (Cucumis melo L.)

Characterizing the diverse melon cultivars for nutrition aids in crop improvement and promoting a healthy diet. Here, we used in vitro assays to characterize the nutritional qualities and health-beneficial effects of 30 melon (Cucumis melo L.) genotypes, including 10 improved cultivars, 16 landraces, and 4 wild types collected from different parts of India. Two landraces (Sidoota and Alper Green) had the highest (12.20 and 11.25) total soluble solids (TSS) contents. The Sidoota and Pappusa landraces had high reducing sugar contents (2.84 and 2.81 mg g⁻¹ fresh weight [FW]). The highest polyphenols contents (22.0 mg g⁻¹ FW) were observed in the landraces Mage Kaayi-2, Budamekaayi, and Small Melon. Reflecting on the primary and secondary metabolite contents, the Mekke Kaayi and Giriyala landraces exhibited high 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (97.6 and 91% at 100 μg mL⁻¹). Additionally, seven of the landraces showed significant nitric oxide (NO) induction activity (>80% inhibition at 200 μg mL⁻¹), indicating their potential health benefits, and seven showed considerable angiotensin-converting enzyme (ACE) inhibition activity (highest in Kashi Madhu), indicating their potential usefulness in reducing hypertension. Genotypes with high health beneficial compounds identified in this study can be used for breeding improved melon cultivars to promote these fruits as well as a healthy diet.

Comparative study of the efficacy of captopril, simvastatin, and L-carnitine as cardioprotective drugs in children with type 1 diabetes mellitus: a randomised controlled trial

OBJECTIVES

To assess the efficacy and safety of captopril, simvastatin, and L-carnitine as cardioprotective drugs in children with type 1 diabetes mellitus on different echocardiographic parameters, electrocardiographic parameter, lipid profile, and carotid intima-media thickness.

METHODS

This randomised controlled trial was conducted on 100 children with type 1 diabetes mellitus for more than 3 years during the period from September 2018 to June 2020. Fifty healthy children of matched age and sex served as a control group. The patients were randomly assigned into four groups (25 children each): no-treatment group who received no cardioprotective drug, simvastatin group who received simvastatin (10-20 mg/day), captopril group who received captopril (0.2 mg/kg/day), and L-carnitine group who received L-carnitine (50 mg/kg/day) for 4 months. Lipid profile, serum troponin I, carotid intima-media thickness, and echocardiographic examinations were performed on all included children before and after the treatment.

RESULTS

Total cholesterol and low-density lipoprotein were significantly decreased in children who received simvastatin or L-carnitine. Triglycerides significantly decreased only in children who received simvastatin. High-density lipoprotein significantly increased in simvastatin and L-carnitine groups only. Serum troponin I decreased significantly in all the three treatment groups. Carotid intima-media thickness showed no significant change in all treatment groups. Echocardiographic parameters significantly improved in simvastatin, L-carnitine, and captopril groups.

CONCLUSION

Captopril, simvastatin, and L-carnitine have a significant beneficial effect on cardiac functions in children with type 1 diabetes mellitus. However, only simvastatin and L-carnitine have a beneficial effect on the lipid profile. The drugs were safe and well tolerated.Clinical trial registration: The clinical trial was registered at www.clinicaltrial.gov (NCT03660293).

Screening natural product extracts for potential enzyme inhibitors: protocols, and the standardisation of the usage of blanks in α-amylase, α-glucosidase and lipase assays

BACKGROUND

Enzyme assays have widespread applications in drug discovery from plants to natural products. The appropriate use of blanks in enzyme assays is important for assay baseline-correction, and the correction of false signals associated with background matrix interferences. However, the blank-correction procedures reported in published literature are highly inconsistent. We investigated the influence of using different types of blanks on the final calculated activity/inhibition results for three enzymes of significance in diabetes and obesity; α-glucosidase, α-amylase, and lipase. This is the first study to examine how different blank-correcting methods affect enzyme assay results. Although assays targeting the above enzymes are common in the literature, there is a scarcity of detailed published protocols. Therefore, we have provided comprehensive, step-by-step protocols for α-glucosidase-, α-amylase- and lipase-inhibition assays that can be performed in 96-well format in a simple, fast, and resource-efficient manner with clear instructions for blank-correction and calculation of results.

RESULTS

In the three assays analysed here, using only a buffer blank underestimated the enzyme inhibitory potential of the test sample. In the absorbance-based α-glucosidase assay, enzyme inhibition was underestimated when a sample blank was omitted for the coloured plant extracts. Similarly, in the fluorescence-based α-amylase and lipase assays, enzyme inhibition was underestimated when a substrate blank was omitted. For all three assays, method six [Raw Data - (Substrate + Sample Blank)] enabled the correction of interferences due to the buffer, sample, and substrate without double-blanking, and eliminated the need to add substrate to each sample blank.

CONCLUSION

The choice of blanks and blank-correction methods contribute to the variability of assay results and the likelihood of underestimating the enzyme inhibitory potential of a test sample. This highlights the importance of standardising the use of blanks and the reporting of blank-correction procedures in published studies in order to ensure the accuracy and reproducibility of results, and avoid overlooked opportunities in drug discovery research due to inadvertent underestimation of enzyme inhibitory potential of test samples resulting from unsuitable blank-correction. Based on our assessments, we recommend method six [RD - (Su + SaB)] as a suitable method for blank-correction of raw data in enzyme assays.

Blockade of Renin Angiotensin System Ameliorates the Cardiac Arrhythmias and Sympathetic Neural Remodeling in Hearts of Type 2 DM Rat Model

OBJECTIVE

The present study was designed to investigate the effects of renin angiotensin system (RAS) blockade on cardiac arrhythmias and sympathetic nerve remodelling in heart tissues of type 2 diabetic rats.

METHODS

Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group: normal rats, b) DM group; after type 2 diabetes induction, rats received 2ml oral saline daily for 4 weeks, c) DM+ ACEi: after type 2 diabetes induction, rats were treated with enalapril (10 mg/kg, orally for 4 weeks) and d) DM+ ARBs: after type 2 diabetes induction, rats were treated with losartan (30 mg/kg, orally for 4 weeks).

RESULTS

In type 2 diabetic rats, the results demonstrated significant prolongation in Q-T interval and elevation of blood sugar, HOMA-IR index, TC, TGs, LDL, serum CK-MB, myocardial damage, myocardial MDA, myocardial norepinephrine and tyrosine hydroxylase (TH) density with significant reduction in serum HDL, serum insulin and myocardial GSH and CAT. On the other hand, blockade of RAS at the level of either ACE by enalapril or angiotensin (Ag) receptors by losartan resulted in significant improvement in ECG parameters (Q-T), cardiac enzymes (CK-MB), cardiac morphology, myocardial oxidative stress (low MDA, high CAT and GSH) and myocardial TH density.

CONCLUSION

RAS plays a role in the cardiac sympathetic nerve sprouting and cardiac arrhythmias induced by type 2 DM and its blockade might have a cardioprotective effect via attenuation of sympathetic nerve fibres remodelling, myocardial norepinephrine contents and oxidative stress.

Inhibition of Angiotensin Converting Enzyme Impairs Anti-staphylococcal Immune Function in a Preclinical Model of Implant Infection

Background: Evidence suggests the renin-angiotensin system (RAS) plays key immunomodulatory roles. In particular, angiotensin-converting enzyme (ACE) has been shown to play a role in antimicrobial host defense. ACE inhibitors (ACEi) and angiotensin receptor blockers (ARB) are some of the most commonly prescribed medications, especially in patients undergoing invasive surgery. Thus, the current study assessed the immunomodulatory effect of RAS-modulation in a preclinical model of implant infection.

Methods:In vitro antimicrobial effects of ACEi and ARBs were first assessed. C57BL/6J mice subsequently received either an ACEi (lisinopril; 16 mg/kg/day), an ARB (losartan; 30 mg/kg/day), or no treatment. Conditioned mice blood was then utilized to quantify respiratory burst function as well as Staphylococcus aureus Xen36 burden ex vivo in each treatment group. S. aureus infectious burden for each treatment group was then assessed in vivo using a validated mouse model of implant infection. Real-time quantitation of infectious burden via bioluminescent imaging over the course of 28 days post-procedure was assessed. Host response via monocyte and neutrophil infiltration within paraspinal and spleen tissue was quantified by immunohistochemistry for F4/80 and myeloperoxidase, respectively.

Results: Blood from mice treated with an ACEi demonstrated a decreased ability to eradicate bacteria when mixed with Xen36 as significantly higher levels of colony forming units (CFU) and biofilm formation was appreciated ex vivo (p < 0.05). Mice treated with an ACEi showed a higher infection burden in vivo at all times (p < 0.05) and significantly higher CFUs of bacteria on both implant and paraspinal tissue at the time of sacrifice (p < 0.05 for each comparison). There was also significantly decreased infiltration and respiratory burst function of immune effector cells in the ACEi group (p < 0.05).

Conclusion: ACEi, but not ARB, treatment resulted in increased S. aureus burden and impaired immune response in a preclinical model of implant infection. These results suggest that perioperative ACEi use may represent a previously unappreciated risk factor for surgical site infection. Given the relative interchangeability of ACEi and ARB from a cardiovascular standpoint, this risk factor may be modifiable.

A narrative review of the potential pharmacological influence and safety of ibuprofen on coronavirus disease 19 (COVID-19), ACE2, and the immune system: a dichotomy of expectation and reality

The coronavirus disease 19 (COVID-19) pandemic is currently the most acute healthcare challenge in the world. Despite growing knowledge of the nature of Severe Acute Respiratory Syndrome coronavirus-2 (SARS-CoV-2), treatment options are still poorly defined. The safety of non-steroidal anti-inflammatory drugs (NSAIDs), specifically ibuprofen, has been openly questioned without any supporting evidence or clarity over dose, duration, or temporality of administration. This has been further conflicted by the initiation of studies to assess the efficacy of ibuprofen in improving outcomes in severe COVID-19 patients. To clarify the scientific reality, a literature search was conducted alongside considerations of the pharmacological properties of ibuprofen in order to construct this narrative review. The literature suggests that double-blind, placebo-controlled study results must be reported and carefully analysed for safety and efficacy in patients with COVID-19 before any recommendations can be made regarding the use of ibuprofen in such patients. Limited studies have suggested: (i) no direct interactions between ibuprofen and SARS-CoV-2 and (ii) there is no evidence to suggest ibuprofen affects the regulation of angiotensin-converting-enzyme 2 (ACE2), the receptor for COVID-19, in human studies. Furthermore, in vitro studies suggest ibuprofen may facilitate cleavage of ACE2 from the membrane, preventing membrane-dependent viral entry into the cell, the clinical significance of which is uncertain. Additionally, in vitro evidence suggests that inhibition of the transcription factor nuclear factor-κB (NF-kB) by ibuprofen may have a role in reducing excess inflammation or cytokine release in COVID-19 patients. Finally, there is no evidence that ibuprofen will aggravate or increase the chance of infection of COVID-19.

Reflections of the Angiotensin Receptor Blocker Recall by the FDA and Repercussions on Healthcare

PURPOSE

Beginning in July of 2018, the FDA issued a voluntary recall regarding the presence of a contaminant found in the manufacturing of valsartan. What would ensue has become a largely unprecedented sequence of alarming events since the FDA began reporting public recalls, withdrawals and safety alerts on their website in 2016. Since then, the United States has been significantly impacted by drug recalls affecting angiotensin receptor blockers. This report arms clinicians with additional guidance and provides a framework for responding appropriately to future similar incidents and includes an overview of the angiotensin receptor blockers, and their effects and safety profiles.

METHODS

This report includes a review of data from all pertinent clinical and scientific sources including information from the FDA's inspection documents and recall website. Additional information is provided on the specific bottles including all lot numbers, expiration dates, etc. RESULTS: The recalls/withdrawals are attributable to the presence of cancer-causing contaminants identified during the manufacturing process from drug manufacturers abroad. The root causes behind the recalls and subsequent shortage appear multifactorial, and stem to a certain extent from the outsourcing of medication manufacturing overseas and lack of quality checks and appropriate oversight.

CONCLUSIONS

This inherent issue is not likely to resolve soon and has eroded the public trust of/in the healthcare system and the pharmaceutical industry. Patients and healthcare providers are significantly affected and should have a full understanding of the matter in order to guide appropriate response and actions.

Basic Mechanisms of Diabetic Heart Disease

Diabetes mellitus predisposes affected individuals to a significant spectrum of cardiovascular complications, one of the most debilitating in terms of prognosis is heart failure. Indeed, the increasing global prevalence of diabetes mellitus and an aging population has given rise to an epidemic of diabetes mellitus-induced heart failure. Despite the significant research attention this phenomenon, termed diabetic cardiomyopathy, has received over several decades, understanding of the full spectrum of potential contributing mechanisms, and their relative contribution to this heart failure phenotype in the specific context of diabetes mellitus, has not yet been fully resolved. Key recent preclinical discoveries that comprise the current state-of-the-art understanding of the basic mechanisms of the complex phenotype, that is, the diabetic heart, form the basis of this review. Abnormalities in each of cardiac metabolism, physiological and pathophysiological signaling, and the mitochondrial compartment, in addition to oxidative stress, inflammation, myocardial cell death pathways, and neurohumoral mechanisms, are addressed. Further, the interactions between each of these contributing mechanisms and how they align to the functional, morphological, and structural impairments that characterize the diabetic heart are considered in light of the clinical context: from the disease burden, its current management in the clinic, and where the knowledge gaps remain. The need for continued interrogation of these mechanisms (both known and those yet to be identified) is essential to not only decipher the how and why of diabetes mellitus-induced heart failure but also to facilitate improved inroads into the clinical management of this pervasive clinical challenge.

Olmesartan attenuates type 2 diabetes-associated liver injury: Cross-talk of AGE/RAGE/JNK, STAT3/SCOS3 and RAS signaling pathways

Olmesartan (OLM), an angiotensin receptor blocker, was tested against diabetes/insulin resistance (IR) models associated with renal/cardiovascular complications. Methods: we tested its potential role against diabetes-induced hepatic hitches using an IR/type2 diabetic (IR/D) model induced by high fat/high fructose diet for 7 weeks ​+ ​a single sub-diabetogenic dose of streptozotocin (35mg/kg; i.p). IR/D rats were orally treated with OLM (10 ​mg/kg), pioglitazone (PIO; 5 or 10 ​mg/kg) or their combinations for 4 consecutive weeks. OLM alone opposed the detrimental effects of IR/D; it significantly improved metabolic parameters, liver function, and abated hepatic oxidative stress, and inflammatory cytokine interleukin-6 (IL-6) and its upstream mediator nuclear factor kappa B. Consequently, OLM turned off the downstream cue p-Jak2/STAT3/SOCS3. Moreover, it suppressed the elevated AGE/RAGE/p-JNK pathway and increased the PPARγ/adiponectin cue to signify its anti-inflammatory and anti-oxidant capacity (GSH, MDA). Nevertheless, co-administration of OLM to PIO showed a synergistic improvement in all the aforementioned parameters in a dose dependent manner. Additionally, OLM with PIO₁₀ provoked a surge in hepatic PPARγ and adiponectin (5 and 6 folds) with a sharp decrease of about 85% in the NF-κB/IL-6/p-STAT3/SCOS3 pathway. These effects were confirmed by the histopathological study. In conclusion, OLM and its combination with PIO enhanced insulin sensitivity and guarded against hepatic complications associated with type 2 diabetes probably via modulating various inter-related pathways; namely, metabolic alteration, renin-angiotensin system, inflammatory trajectories, as well as oxidative stress. This study manifests the potential synergistic effects of OLM as an adjuvant therapy to the conventional antidiabetic therapies.

Biomimetic nanoparticle technology for cardiovascular disease detection and treatment

Cardiovascular disease (CVD), which encompasses a number of conditions that can affect the heart and blood vessels, presents a major challenge for modern-day healthcare. Nearly one in three people has some form of CVD, with many suffering from multiple or intertwined conditions that can ultimately lead to traumatic events such as a heart attack or stroke. While the knowledge obtained in the past century regarding the cardiovascular system has paved the way for the development of life-prolonging drugs and treatment modalities, CVD remains one of the leading causes of death in developed countries. More recently, researchers have explored the application of nanotechnology to improve upon current clinical paradigms for the management of CVD. Nanoscale delivery systems have many advantages, including the ability to target diseased sites, improve drug bioavailability, and carry various functional payloads. In this review, we cover the different ways in which nanoparticle technology can be applied towards CVD diagnostics and treatments. The development of novel biomimetic platforms with enhanced functionalities is discussed in detail.

Clinical Outcomes at 2 Years Between Beta-Blockade with ACE Inhibitors or ARBs in Patients with AMI Who Underwent Successful PCI with DES: A Retrospective Analysis of 23,978 Patients in the Korea AMI Registry

INTRODUCTION

Data concerning the clinical impact of combination therapy with β-blockers (BBs) + angiotensin-converting enzyme inhibitors (ACEIs) compared with BBs + angiotensin-receptor blockers (ARBs) in patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI) with drug-eluting stents (DES) are limited.

OBJECTIVE

We compared the clinical outcomes at 2 years between these two combination therapies.

METHODS

We enrolled 23,978 patients with AMI who underwent successful PCI with DES between January 2005 and June 2015 from the Korea AMI Registry (KAMIR) and divided them into the two groups: BB + ACEI (n = 17,310) and BB + ARB (n = 6668). The primary endpoint was major adverse cardiac events (MACE), defined as all-cause death, recurrent myocardial infarction (re-MI), target lesion revascularization (TLR), target vessel revascularization (TVR), and non-TVR. The secondary endpoints were the cumulative incidences of individual components of MACE and target vessel failure (TVF), a composite of death related to the target vessel, re-MI, or clinically driven TVR.

RESULTS

The relative risk of MACE was higher in the BB + ARB group than in the BB + ACEI group after propensity score-matched (PSM) analysis (hazard ratio [HR] 1.204; 95% confidence interval [CI] 1.057-1.370; p = 0.005). The relative risks of all-cause death (HR 1.435 [95% CI 1.117-1.845]; p = 0.005), cardiac death (HR 1.733 [95% CI 1.253-2.396]; p = 0.001), TVR (HR 1.437 [95% CI 1.157-1.784]; p = 0.001), and TVF (HR 1.231 [95% CI 1.065-1.424]; p = 0.005) were also higher in the BB + ARB group after PSM.

CONCLUSIONS

The BB + ACEI group demonstrated reduced cumulative incidences of MACE, all-cause death, cardiac death, TVR, and TVF compared with the BB + ARB group in patients with AMI who underwent successful PCI with DES during a 2-year follow-up period.

Powering Amyloid Beta Degrading Enzymes: A Possible Therapy for Alzheimer's Disease

The accumulation of amyloid beta (Aβ) in the brain is believed to play a central role in the development and progression of Alzheimer's disease. Revisions to the amyloid cascade hypothesis now acknowledge the dynamic equilibrium in which Aβ exists and the importance of enzymes involved in the production and breakdown of Aβ in maintaining healthy Aβ levels. However, while a wealth of pharmacological and immunological therapies are being generated to inhibit the Aβ-producing enzymes, β-site APP cleavage enzyme 1 and γ-secretase, the therapeutic potential of stimulating Aβ-degrading enzymes such as neprilysin, endothelin-converting enzyme-1 and insulin-degrading enzyme remains relatively unexplored. Recent evidence indicates that increasing Aβ degradation as opposed to inhibiting synthesis is a more effective strategy to prevent Aβ build-up. Therefore Aβ degrading enzymes have become valuable targets of therapy. In this review, we discuss the pathway of Aβ synthesis and clearance along with the opportunities they present for therapeutic intervention, the benefits of increasing the expression/activity of Aβ-degrading enzymes, and the untapped therapeutic potential of enzyme activation.

Luminescent Strategies for Label-Free G-Quadruplex-Based Enzyme Activity Sensing

By catalyzing highly specific and tightly controlled chemical reactions, enzymes are essential to maintaining normal cellular physiology. However, aberrant enzymatic activity can be linked to the pathogenesis of various diseases. Therefore, the unusual activity of particular enzymes can represent testable biomarkers for the diagnosis or screening of certain diseases. In recent years, G-quadruplex-based platforms have attracted wide attention for the monitoring of enzymatic activities. In this Personal Account, we discuss our group's works on the development of G-quadruplex-based sensing system for enzyme activities by using mainly iridium(III) complexes as luminescent label-free probes. These studies showcase the versatility of the G-quadruplex for developing assays for a variety of different enzymes.

Review: The metabolic syndrome as an endocrine disease: is there an effective pharmacotherapeutic strategy optimally targeting the pathogenesis?

The metabolic syndrome (MetS) represents a combination of cardiovascular risk determinants such as obesity, insulin resistance and lipid abnormalities such as hypertriglyceridemia, increased free fatty acids, low high-density-cholesterol and hypertension. As a multiple component condition it imparts a doubling of relative risk for atherosclerotic cardiovascular disease (ASCVD). It is currently controversial which component of the syndrome carries what weight. There is even a considerable debate whether the risk for ASCVD is greater in patients diagnosed with MetS than that by the individual risk factors. At present, no unifying pathogenetic mechanism can explain the metabolic syndrome and there is no unique treatment for it. This review summarizes and critically reviews the currently available clinical and scientific evidence for the concept that the MetS is causally an endocrine disease and discusses pharmacotherapeutic strategies targeting the pathogenesis rather than single symptoms of the cluster.

Renin-angiotensin-aldosterone system in insulin resistance and metabolic syndrome

Obesity and its consequent complications such as hypertension and metabolic syndrome are increasing in incidence in almost all countries. Insulin resistance is common in obesity. Renin- angiotensin system (RAS) is an important target in the treatment of hypertension and drugs that act on RAS improve insulin resistance and decrease the incidence of type 2 diabetes mellitus, explaining the close association between hypertension and type 2 diabetes mellitus. RAS influences food intake by modulating the hypothalamic expression of neuropeptide Y and orexins via AMPK dephosphorylation. Estrogen reduces appetite by its action on the brain in a way similar to leptin, an anorexigenic action that seems to be mediated via hypothalamic pro-opiomelanocortin (POMC) neurons in the arcuate nucleus and synaptic plasticity in the arcuate nucleus similar to leptin. Estrogen stimulates lipoxin A₄, a potent vasodilator and platelet anti-aggregator. Since both RAS and estrogen act on the hypothalamic neuropeptides and regulate food intake and obesity, it is likely that RAS modulates LXA₄ synthesis. Thus, it is proposed that Angiotensin-II receptor blockers and angiotensin-converting enzymes and angiotensin-II antagonists may have the ability to augment LXA₄ synthesis and thus bring about their beneficial actions.

Combined Treatment With Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers: A Review of the Current Evidence

Several studies have shown that angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are useful in the treatment of hypertension, cardiovascular disease, chronic heart failure, and some types of nephropathy. In this context, dual renin-angiotensin system blockade with both angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers may be more effective than treatment with each agent alone. Many clinical trials have demonstrated the beneficial effect of this combined treatment on proteinuria, hypertension, heart failure, and cardiovascular events. Moreover, these studies demonstrated that dual renin-angiotensin system blockade is generally safe and well tolerated. Long-term studies are under way to confirm these effects and also investigate the effectiveness of dual reninangiotensin system blockade on cerebrovascular disease and prevention of type 2 diabetes mellitus. These studies are expected to define the optimal use of combination treatment in everyday clinical practice. This review considers the most important clinical trials that evaluated the effect of dual renin-angiotensin system blockade on blood pressure, heart failure, and renal function.

Kidney tubules: intertubular, vascular, and glomerular cross-talk

PURPOSE OF REVIEW

The kidney mediates the excretion or conservation of water and electrolytes in the face of changing fluid and salt intake and losses. To ultrafilter and reabsorb the exact quantities of free water and salts to maintain euvolemia a range of endocrine, paracrine, and hormonal signaling systems have evolved linking the tubules, capillaries, glomeruli, arterioles, and other intrinsic cells of the kidney. Our understanding of these systems remains incomplete.

RECENT FINDINGS

Recent work has provided new insights into the workings of the communication pathways between tubular segments and the glomeruli and vasculature, with novel therapeutic agents in development. Particular progress has also been made in the visualization of tubuloglomerular feedback.

SUMMARY

The review summarizes our current understanding of pathway functions in health and disease, as well as future therapeutic options to protect the healthy and injured kidney.

Night-time blood pressure: a role in the prediction and prevention of diabetes?

This commentary discusses and reviews the implications of two studies published in this issue of Diabetologia by Hermida et al (DOIs: 10.1007/s00125-015-3748-8 and 10.1007/s00125-015-3749-7 ) suggesting that high nocturnal blood pressure could have a role in the prediction of diabetes and act as a therapeutic target to prevent diabetes. This overview addresses the clinical implications of this work and new research that is likely to advance this field. It also provides a framework for interpreting claims of causality from observational studies and clinical trials.

Effect of enalapril in cisplatin-induced nephrotoxicity in rats; gender-related difference

Background:

The function of renin angiotensin system (RAS) is gender-related, and this system affects cisplatin (CP)-induced nephrotoxicity. In this study, we compared the effect of enalapril as an angiotensin-converting enzyme (ACE) inhibitor on CP-induced nephrotoxicity between male and female rats.

Materials and Methods:

Sixty-two adult male and female Wistar rats were divided into eight groups. Both genders received CP (2.5 mg/kg, i.p.) and enalapril (30 mg/kg, i.p.) for 7 days in compared with CP alone or enalapril alone or vehicle alone treated groups. At the end of the experiment, blood samples were obtained, and the kidney tissue was investigated for histopathological changes.

Results:

CP increased the serum levels of blood urea nitrogen and creatinine as well as kidney weight and kidney tissue damage score in both genders (P < 0.05). However, not only enalapril failed to ameliorate the aforementioned parameters in both genders, but also it intensified nephrotoxicity in females (P < 0.05). In addition, enalapril enhanced body weight loss induced by CP in females (P < 0.05). CP alone decreased kidney level of nitrite in both genders (P < 0.05) and enalapril could not reverse this decreasing. The combination of enalapril and CP significantly increased serum level of nitrite in females, but this was not observed in males (P < 0.05).

Conclusion:

Enalapril as an ACE inhibitor failed to ameliorate nephrotoxicity induced by CP in both male and female rats. In addition, enalapril aggravated CP-induced nephrotoxicity in female possibly due to gender-dependent RAS response.

Effect of angiotensin II-induced arterial hypertension on the voltage-dependent contractions of mouse arteries

Arterial hypertension (AHT) affects the voltage dependency of L-type Ca(2+) channels in cardiomyocytes. We analyzed the effect of angiotensin II (AngII)-induced AHT on L-type Ca(2+) channel-mediated isometric contractions in conduit arteries. AHT was induced in C57Bl6 mice with AngII-filled osmotic mini-pumps (4 weeks). Normotensive mice treated with saline-filled osmotic mini-pumps were used for comparison. Voltage-dependent contractions mediated by L-type Ca(2+) channels were studied in vaso-reactive studies in vitro in isolated aortic and femoral arteries by using extracellular K(+) concentration-response (KDR) experiments. In aortic segments, AngII-induced AHT significantly sensitized isometric contractions induced by elevated extracellular K(+) and depolarization. This sensitization was partly prevented by normalizing blood pressure with hydralazine, suggesting that it was caused by AHT rather than by direct AngII effects on aortic smooth muscle cells. The EC50 for extracellular K(+) obtained in vitro correlated significantly with the rise in arterial blood pressure induced by AngII in vivo. The AHT-induced sensitization persisted when aortic segments were exposed to levcromakalim or to inhibitors of basal nitric oxide release. Consistent with these observations, AngII-treatment also sensitized the vaso-relaxing effects of the L-type Ca(2+) channel blocker diltiazem during K(+)-induced contractions. Unlike aorta, AngII-treatment desensitized the isometric contractions to depolarization in femoral arteries pointing to vascular bed specific responses of arteries to hypertension. AHT affects the voltage-dependent L-type Ca(2+) channel-mediated contraction of conduit arteries. This effect may contribute to the decreased vascular compliance in AHT and explain the efficacy of Ca(2+) channel blockers to reduce vascular stiffness and central blood pressure in AHT.

Valsartan protects HK-2 cells from contrast media-induced apoptosis by inhibiting endoplasmic reticulum stress

Contrast-induced acute kidney injury (CI-AKI) is associated with increasing in-hospital and long-term adverse clinical outcomes in high-risk patients undergoing percutaneous coronary intervention (PCI). Contrast media (CM)-induced renal tubular cell apoptosis is reported to participate in this process by activating endoplasmic reticulum (ER) stress. An angiotensin II type 1 receptor (AT1R) antagonist can alleviate ER stress-induced renal apoptosis in streptozotocin (STZ)-induced diabetic mice and can reduce CM-induced renal apoptosis by reducing oxidative stress and reversing the enhancement of bax mRNA and the reduction of bcl-2 mRNA, but the effect of the AT1R blocker on ER stress in the pathogenesis of CI-AKI is still unknown. In this study, we explored the effect of valsartan on meglumine diatrizoate-induced human renal tubular cell apoptosis by measuring changes in ER stress-related biomarkers. The results showed that meglumine diatrizoate caused significant cell apoptosis by up-regulating the expression of ER stress markers, including glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), CCAAT/enhancer-binding protein-homologous protein (CHOP) and caspase 12, in a time- and dose-dependent manner, which could be alleviated by preincubation with valsartan. In conclusion, valsartan had a potential nephroprotective effect on meglumine diatrizoate-induced renal cell apoptosis by inhibiting ER stress.

Effect of enalapril maleate on ghrelin levels in metabolic syndrome in rats

We have explored how enalapril affects ghrelin levels in serum and renal tissues of rats with fructose-induced MetS, using 5-week-old Wistar albino male rats weighing 220 ± 20 g. They divided into 5 groups: (i) control (CT), no fructose supplement fed on standard rat pellet and tap water for 60 days, (ii) metabolic syndrome (MetS) fed with 10% fructose for 60 days, (iii) rats after metabolic syndrome developed treated with enalapril over 30 days (MetS+E30), (iv) rats in which only enalapril was administered for 60 days (E60), and (v) MetS-treated with enalapril for 60 days (MetS+E60). Enalapril maleate was given at 20mg/kg per day by gavage. Fasting serum insulin, uric acid, triglyceride, low-density lipoprotein cholesterol and total cholesterol levels were significantly higher, and the amount of high density lipoprotein cholesterol, and acylated and desacyl ghrelin levels was significantly lower in the MetS groups. Ghrelins were significantly lower in all 3 groups, which were administered enalapril than that of MetS and the control group. Immunohistochemical staining showed that the density of ghrelin was parallel to the serum levels of the peptide. Ghrelin immunoreactivity in the kidneys was of moderate density in the distal and collecting tubules, mild density in the proximal tubule and glomeruli, whereas the density decreased in the MetS group and other enalapril-treated groups. In conclusion, ghrelin levels in MetS groups were significantly lower than control group, and thus Enalapril treatment improves components of MetS and has direct effects on serum ghrelin levels that are independent of MetS.

Peripheral arterial disease and revascularization of the diabetic foot

Diabetes is a complex disease with many serious potential sequelae, including large vessel arterial disease and microvascular dysfunction. Peripheral arterial disease is a common large vessel complication of diabetes, implicated in the development of tissue loss in up to half of patients with diabetic foot ulceration. In addition to peripheral arterial disease, functional changes in the microcirculation also contribute to the development of a diabetic foot ulcer, along with other factors such as infection, oedema and abnormal biomechanical loading. Peripheral arterial disease typically affects the distal vessels, resulting in multi-level occlusions and diffuse disease, which often necessitates challenging distal revascularisation surgery or angioplasty in order to improve blood flow. However, technically successful revascularisation does not always result in wound healing. The confounding effects of microvascular dysfunction must be recognised--treatment of a patient with a diabetic foot ulcer and peripheral arterial disease should address this complex interplay of pathophysiological changes. In the case of non-revascularisable peripheral arterial disease or poor response to conventional treatment, alternative approaches such as cell-based treatment, hyperbaric oxygen therapy and the use of vasodilators may appear attractive, however more robust evidence is required to justify these novel approaches.

Insulin receptor substrate-2 (Irs2) in endothelial cells plays a crucial role in insulin secretion

Endothelial cells are considered to be essential for normal pancreatic β-cell function. The current study attempted to demonstrate the role of insulin receptor substrate-2 (Irs2) in endothelial cells with regard to insulin secretion. Endothelial cell-specific Irs2 knockout (ETIrs2KO) mice exhibited impaired glucose-induced, arginine-induced, and glucagon-induced insulin secretion and showed glucose intolerance. In batch incubation and perifusion experiments using isolated islets, glucose-induced insulin secretion was not significantly different between the control and the ETIrs2KO mice. In contrast, in perfusion experiments, glucose-induced insulin secretion was significantly impaired in the ETIrs2KO mice. The islet blood flow was significantly impaired in the ETIrs2KO mice. After the treatment of these knockout mice with enalapril maleate, which improved the islet blood flow, glucose-stimulated insulin secretion was almost completely restored to levels equal to those in the control mice. These data suggest that Irs2 deletion in endothelial cells leads to a decreased islet blood flow, which may cause impaired glucose-induced insulin secretion. Thus, Irs2 in endothelial cells may serve as a novel therapeutic target for preventing and ameliorating type 2 diabetes and metabolic syndrome.

The renin-angiotensin system and prevention of age-related functional decline: where are we now?

Declining physical function is a major health problem for older adults as it is associated with multiple comorbidities and mortality. Exercise has been shown to improve physical function, though response to exercise is variable. Conversely, drugs targeting the renin-angiotensin system (RAS) pathway, including angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs), are also reported to improve physical function. In the past decade, significant strides have been made to understand the complexity and specificity of the RAS system as it pertains to physical function in older adults. Prior findings have also determined that interactions between antihypertensive medications and exercise may influence physical function above and beyond either factor alone. We review the latest research on RAS, exercise, and physical function for older adults. We also outline future research aims in this area, including genetic influences and clinical phenotyping, for the purpose of maintaining or improving physical function through tailored treatments.

Critical insights into the beneficial and protective actions of the kallikrein-kinin system

Hypertension is characterized by an imbalance between the renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS). Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II AT-1 receptor antagonists (also known as sartans or ARBs) are potent modulators of these systems and are highly effective as first-line treatments for hypertension, diabetic nephropathies, and diseases of the brain and coronary arteries. However, these agents are mechanistically distinct and should not be considered interchangeable. In this mini-review, we provide novel insights into the often neglected roles of the KKS in the beneficial, protective, and reparative actions of ACEIs. Indeed, ACEIs are the only antihypertensive drugs that properly reduce the imbalance between the RAS and the KKS, thereby restoring optimal cardiovascular homeostasis and significantly reducing morbidity and the risk of all-cause mortality among individuals affected by hypertension and other cardiovascular diseases.

Insulin resistance as a therapeutic target for chronic kidney disease

Insulin resistance (IR) is a prevalent metabolic feature in chronic kidney disease (CKD). Postreceptor insulin-signaling defects have been observed in uremia. A decrease in the activity of phosphatidylinositol 3-kinase appears critical in the pathophysiology of CKD-associated IR. Lipotoxicity due to ectopic accumulation of lipid moieties has recently emerged as another mechanism by which CKD and/or associated metabolic disorders may lead to IR through impairment of various insulin-signaling molecules. Metabolic acidosis, anemia, excess of fat mass, inflammation, vitamin D deficiency, adipokine imbalance, physical inactivity, and the accumulation of nitrogenous compounds of uremia all contribute to CKD-associated IR. The clinical impacts of IR in this setting are numerous, including endothelial dysfunction, increased cardiovascular mortality, muscle wasting, and possibly initiation and progression of CKD. This is why IR may be a therapeutic target in the attempt to improve outcomes in CKD. General measures to improve IR are directed to counteract causal factors. The use of pharmaceutical agents such as inhibitors of the renin-angiotensin system may improve IR in hypertensive and CKD patients. Pioglitazone appears a safe and promising therapeutic agent to reduce IR and uremic-associated abnormalities. However, interventional studies are needed to test if the reduction and/or normalization of IR may actually improve outcomes in these patients.

Peroxisome proliferator-activated receptor gamma concentrations in newly diagnosed hypertension patients and the metabolic effects of olmesartan

BACKGROUND AND AIMS

We undertook this study to investigate the effects of olmesartan treatment on PPAR-gamma (PPAR-γ) concentrations and metabolic syndrome (MetS) components in hypertensive (HT) patients.

METHODS

The study included 46 newly diagnosed hypertensive patients and 30 healthy controls. All hypertensive patients were given 40 mg of olmesartan, and they were evaluated weekly in the first month and then twice weekly during follow-up visits. At the end of 3 months, MetS components were assessed and serum PPAR-γ transcription factor concentrations were again measured.

RESULTS

MetS was noted in 80.4% of HT patients. Serum PPAR-γ transcription factor concentration were significantly lower in those with HT compared with the controls (p = 0.005). PPAR-γ concentrations of controls were 1.14-fold higher than hypertensive patients. HDL levels were significantly increased after treatment (p = 0.004), triglyceride, total cholesterol, fasting blood glucose (FBG), and LDL levels were significantly reduced (p <0.05). There was a tendency toward increased PPAR-γ concentrations after treatment, but these were not statistically significant (p = 0.154).

CONCLUSIONS

Olmesartan treatment was found to generate beneficial effects on MetS parameters in HT patients but did not produce any significant increases in serum PPAR-γ transcription factor concentration.

Diabetic cardiomyopathy: mechanisms and new treatment strategies targeting antioxidant signaling pathways

Cardiovascular disease is the primary cause of morbidity and mortality among the diabetic population. Both experimental and clinical evidence suggest that diabetic subjects are predisposed to a distinct cardiomyopathy, independent of concomitant macro- and microvascular disorders. 'Diabetic cardiomyopathy' is characterized by early impairments in diastolic function, accompanied by the development of cardiomyocyte hypertrophy, myocardial fibrosis and cardiomyocyte apoptosis. The pathophysiology underlying diabetes-induced cardiac damage is complex and multifactorial, with elevated oxidative stress as a key contributor. We now review the current evidence of molecular disturbances present in the diabetic heart, and their role in the development of diabetes-induced impairments in myocardial function and structure. Our focus incorporates both the contribution of increased reactive oxygen species production and reduced antioxidant defenses to diabetic cardiomyopathy, together with modulation of protein signaling pathways and the emerging role of protein O-GlcNAcylation and miRNA dysregulation in the progression of diabetic heart disease. Lastly, we discuss both conventional and novel therapeutic approaches for the treatment of left ventricular dysfunction in diabetic patients, from inhibition of the renin-angiotensin-aldosterone-system, through recent evidence favoring supplementation of endogenous antioxidants for the treatment of diabetic cardiomyopathy. Novel therapeutic strategies, such as gene therapy targeting the phosphoinositide 3-kinase PI3K(p110α) signaling pathway, and miRNA dysregulation, are also reviewed. Targeting redox stress and protective protein signaling pathways may represent a future strategy for combating the ever-increasing incidence of heart failure in the diabetic population.

Therapeutic interventions for hypertension in metabolic syndrome: a comprehensive approach

Hypertension is a major component of the metabolic syndrome and a major cardiovascular risk factor. Both disorders are rapidly increasing in frequency, with hypertension affecting nearly 60 million Americans and over 1 billion people worldwide, and metabolic syndrome affecting 44% of the US population above the age of 60 years. Sedentary lifestyle, together with obesity and aging of the population, are the major contributing factors for this growing epidemic. Hypertension in metabolic syndrome possesses unique pathophysiological aspects that have considerable implications on therapy of this disease. In this article, we review the pathophysiology and provide a rationale for the current therapeutic options in light of the most recent clinical trials in the field.

Serum agonistic autoantibodies against type-1 angiotensin II receptor titer in patients with epithelial ovarian cancer: a potential role in tumor cell migration and angiogenesis

BACKGROUND

Although agonistic autoantibodies against type-1 angiotensin-II receptor (AT1-AA) are frequently detected in women with preeclampsia, the clinical significance of AT1-AA in association with epithelial ovarian cancer (EOC) has not been identified.

METHODS

In an attempt to clarify this issue, we measured serum AT1-AA titer from EOC patients (n = 89) and healthy normal subjects (n = 55), correlated AT1-AA titer with EOC stage and grade, and demonstrated the effects of purified AT1-AA on migration of ovarian cancer cells and angiogenesis of chick embryo chorioallantoic membrane.

RESULTS

We found that the AT1-AA titer was significantly higher in EOC patients compared with healthy control subjects (1.77 ± 0.28 vs. 0.35 ± 0.05, P < 0.01). The positive rate was averaged by 72.1±2.5% in EOC patients and 15.5 ±1.5% in control (P < 0.01). Increased AT1-AA titer in EOC patients was associated with advanced stages and grades of EOC, and positively correlated with level of vascular endothelial growth factor (r = 0.855, P < 0.01). Furthermore, AT1-AA directly stimulated migration of ovarian cancer cells and enhanced microvascular density of chick embryo chorioallantoic membrane. These AT1-AA-mediated effects were significantly blocked either by an autoantibody-neutralizing peptide or an angiotensin II type I receptor antagonist, losartan.

CONCLUSION

Taken together, we found that a higher serum AT1-AA titer may be associated with advanced progression of EOC in patients and play an important role in development of EOC by promoting cancer cell migration and angiogenesis. These findings implicate that AT1-AA might be selected as a detectable biomarker and potential therapeutic target in diagnosis and treatment of EOC patients.

Living high training low induces physiological cardiac hypertrophy accompanied by down-regulation and redistribution of the renin-angiotensin system

AIM

Living high training low" (LHTL) is an exercise-training protocol that refers living in hypoxia stress and training at normal level of O2. In this study, we investigated whether LHTL caused physiological heart hypertrophy accompanied by changes of biomarkers in renin-angiotensin system in rats.

METHODS

Adult male SD rats were randomly assigned into 4 groups, and trained on living low-sedentary (LLS, control), living low-training low (LLTL), living high-sedentary (LHS) and living high-training low (LHTL) protocols, respectively, for 4 weeks. Hematological parameters, hemodynamic measurement, heart hypertrophy and plasma angiotensin II (Ang II) level of the rats were measured. The gene and protein expression of angiotensin-converting enzyme (ACE), angiotensinogen (AGT) and angiotensin II receptor I (AT1) in heart tissue was assessed using RT-PCR and immunohistochemistry, respectively.

RESULTS

LLTL, LHS and LHTL significantly improved cardiac function, increased hemoglobin concentration and RBC. At the molecular level, LLTL, LHS and LHTL significantly decreased the expression of ACE, AGT and AT1 genes, but increased the expression of ACE and AT1 proteins in heart tissue. Moreover, ACE and AT1 protein expression was significantly increased in the endocardium, but unchanged in the epicardium.

CONCLUSION

LHTL training protocol suppresses ACE, AGT and AT1 gene expression in heart tissue, but increases ACE and AT1 protein expression specifically in the endocardium, suggesting that the physiological heart hypertrophy induced by LHTL is regulated by region-specific expression of renin-angiotensin system components.

Hypertension management in the high cardiovascular risk population

The incidence of hypertension is increasing every year. Blood pressure (BP) control is an important therapeutic goal for the slowing of progression as well as for the prevention of Cardiovascular disease. The management of hypertension in the high cardiovascular risk population remains a real challenge as the population continues to age, the incidence of diabetes increases, and more and more people survive acute myocardial infarction. We will review hypertension management in the high cardiovascular risk population: patients with coronary heart disease (CHD) and heart failure (HF) as well as in diabetic patients.