Cerebrovasculoprotective effects of azilsartan medoxomil in diabetes

Implication of endoplasmic reticulum stress and mitochondrial perturbations in remote liver injury after renal ischemia/reperfusion in rats: potential protective role of azilsartan

Objectives: Distant liver injury is a complication of renal ischemia-reperfusion (I/R) injury, which imposes mortality and economic burden. This study aimed to elucidate the cross-talk of endoplasmic reticulum (ER) stress and mitochondrial perturbations in renal I/R-induced liver injury, and the potential hepatoprotective effect of azilsartan (AZL).Methods: Male albino Wister rats were pre-treated with AZL (3 mg/kg/day, PO) for 7 days then a bilateral renal I/R or sham procedure was performed. Activities of liver enzymes were assessed in plasma. The structure and ultra-structure of hepatocytes were assessed by light and electron microscopy. Markers of ER stress, mitochondrial biogenesis and apoptosis were analyzed in livers of rats.Results: Renal ischemic rats showed higher plasma levels of liver enzymes than sham-operated rats, coupled with histological and ultra-structural alterations in hepatocytes. Mechanistically, there was up-regulation of ER stress markers and suppression of mitochondrial biogenesis-related proteins and enhanced apoptosis in livers of renal ischemic rats. These abnormalities were almost abrogated by AZL pretreatment.Discussion: Our findings uncovered the involvement of mitochondrial perturbations, ER stress and apoptosis in liver injury following renal I/R, and suggested AZL as a preconditioning strategy to ameliorate remote liver injury in patients susceptible to renal I/R after adequate clinical testing.

Azilsartan improves urinary albumin excretion in hypertension mice

Hypertension is one of the most important risk factors for chronic kidney diseases, leading to hypertensive nephrosclerosis, including excessive albuminuria. Azilsartan, an angiotensin II type 1 receptor blocker, has been widely used for the treatment of hypertension. However, the effects of Azilsartan on urinary albumin excretion in hypertension haven't been reported before. In this study, we investigated whether Azilsartan possesses a beneficial property against albuminuria in mice treated with angiotensin II and a high-salt diet (ANG/HS). Compared to the control group, the ANG/HS group had higher blood pressure, oxidative stress, and inflammatory response, all of which were rescued by Azilsartan dose-dependently. Importantly, the ANG/HS-induced increase in urinary albumin excretion and decrease in the expression of occludin were reversed by Azilsartan. Additionally, it was shown that increased fluorescence intensity of FITC-dextran, declined trans-endothelial electrical resistance (TEER) values, and reduction of occludin and krüppel-like factor 2 (KLF2) were observed in ANG/HS-treated human renal glomerular endothelial cells (HrGECs), then prevented by Azilsartan. Moreover, the regulatory effect of Azilsartan on endothelial monolayer permeability in ANG/HS-treated HrGECs was abolished by the knockdown of KLF2, indicating KLF2 is required for the effect of Azilsartan. We concluded that Azilsartan alleviated diabetic nephropathy-induced increase in Uterine artery embolization (UAE) mediated by the KLF2/occludin axis.

Therapeutic Implications of Renin-Angiotensin System Modulators in Alzheimer's Dementia

The Renin-Angiotensin System (RAS) has attracted considerable interest beyond its traditional cardiovascular role due to emerging data indicating its potential involvement in neurodegenerative diseases, including Alzheimer's dementia (AD). This review investigates the therapeutic implications of RAS modulators, specifically focusing on angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), and renin inhibitors in AD. ACEIs, commonly used for hypertension, show promise in AD by reducing angiotensin (Ang) II levels. This reduction is significant as Ang II contributes to neuroinflammation, oxidative stress, and β-amyloid (Aβ) accumulation, all implicated in AD pathogenesis. ARBs, known for vasodilation, exhibit neuroprotection by blocking Ang II receptors, improving cerebral blood flow and cognitive decline in AD models. Renin inhibitors offer a novel approach by targeting the initial RAS step, displaying anti-inflammatory and antioxidant effects that mitigate AD degeneration. Preclinical studies demonstrate RAS regulation's favorable impact on neuroinflammation, neuronal damage, cognitive function, and Aβ metabolism. Clinical trials on RAS modulators in AD are limited, but with promising results, ARBs being more effective that ACEIs in reducing cognitive decline. The varied roles of ACEIs, ARBs, and renin inhibitors in RAS modulation present a promising avenue for AD therapeutic intervention, requiring further research to potentially transform AD treatment strategies.

Azilsartan Suppresses Osteoclastogenesis and Ameliorates Ovariectomy-Induced Osteoporosis by Inhibiting Reactive Oxygen Species Production and Activating Nrf2 Signaling

Osteoporosis is characterized by a decrease in bone mass and destruction of the bone microarchitecture, and it commonly occurs in postmenopausal women and the elderly. Overactivation of osteoclasts caused by the inflammatory response or oxidative stress leads to osteoporosis. An increasing number of studies have suggested that intracellular reactive oxygen species (ROS) are strongly associated with osteoclastogenesis. As a novel angiotensin (Ang) II receptor blocker (ARB), azilsartan was reported to be associated with the inhibition of intracellular oxidative stress processes. However, the relationship between azilsartan and osteoclastogenesis is still unknown. In this study, we explored the effect of azilsartan on ovariectomy-induced osteoporosis in mice. Azilsartan significantly inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-mediated osteoclastogenesis and downregulated the expression of osteoclast-associated markers (Nfatc1, c-Fos, and Ctsk) in vitro. Furthermore, azilsartan reduced RANKL-induced ROS production by increasing the expression of nuclear factor erythroid 2-related factor 2 (Nrf2). Mechanistically, azilsartan inhibited the activation of MAPK/NF-κB signaling pathways, while Nrf2 silencing reversed the inhibitory effect of azilsartan on MAPK/NF-κB signaling pathways. Consistent with the in vitro data, azilsartan administration ameliorated ovariectomy (OVX)-induced osteoporosis, and decreased ROS levels in vivo. In conclusion, azilsartan inhibited oxidative stress and may be a novel treatment strategy for osteoporosis caused by osteoclast overactivation.

Activation of protease-activated receptor 2 is associated with blood pressure regulation and proteinuria reduction in metabolic syndrome

Metabolic syndrome (MetS) increases the risk of kidney disease. In SHRSP.Z-Leprfa /IzmDmcr (SHRSP.ZF) rats with MetS, protease-activated receptor 2 (PAR2)-mediated vasorelaxation is preserved in the aorta at 20 weeks of age (weeks) via enhancement of nitric oxide production but impaired at 30 weeks by oxidative stress. However, impairment of PAR2-mediated vasorelaxation of renal arteries and its possible implications for kidney disease are unclear. We used organ baths to assess PAR2-mediated vasorelaxation of isolated renal arteries, colorimetric methods to measure urinary protein levels as an index of renal function, and western blot to determine expression of PAR2 and nephrin proteins in the kidneys of SHRSP.ZF rats at 10, 20, and 30 weeks. We assessed renal arteries and kidney function for effects of orally administered GB88, a pathway-dependent PAR2 antagonist, from 10 to 18 weeks, and azilsartan, an angiotensin II type 1 receptor blocker, from 13 to 23 weeks. PAR2-mediated vasorelaxation was slightly lower at 20 weeks and attenuated significantly at 30 weeks compared with those at 10 weeks. Urinary protein levels were increased at 20 and 30 weeks. Decreased protein expression of PAR2 and nephrin in the kidney were observed at 30 weeks. Administration of GB88 increased blood pressure (BP) and proteinuria. Azilsartan reduced the high BP and the impaired PAR2-mediated vasorelaxation, but did not restore the increase in urinary protein levels and decreased PAR2 and nephrin protein expression in the kidney. PAR2 activation in the kidney may be associated with maintenance of BP and urinary protein excretion in MetS.

Inhibition of Ephrin-B2 in brain pericytes decreases cerebral pathological neovascularization in diabetic rats

We have previously shown that diabetes causes dysfunctional cerebral neovascularization that increases the risk for cerebrovascular disorders such as stroke and cognitive impairment. Pericytes (PCs) play a pivotal role in the angiogenic process through their interaction with the endothelial cells (EC). Yet, the role of PCs in dysfunctional cerebral neovascularization in diabetes is unclear. In the present study, we tested the hypothesis that the increased proangiogenic Ephrin-B2 signaling in PCs contributes to the dysfunctional cerebral neovascularization in diabetes. Type-II diabetes was induced by a combination of high fat diet and low dose streptozotocin injection in male Wistar rats. Selective in vivo Ephrin-B2 silencing in brain PCs was achieved using the stereotactic injection of adeno-associated virus (AAV) with NG2-promoter that expresses Ephrin-B2 shRNA. Neovascularization was assessed using vascular fluorescent dye stain. Novel object recognition (NOR) test was used to determine cognitive functions. Human brain microvascular pericytes HBMVPCs were grown in high glucose 25 mM and palmitate 200 uM (HG/Pal) to mimic diabetic conditions. Scratch migration and tube formation assays were conducted to evaluate PC/EC interaction and angiogenic functions in PC/EC co-culture. Diabetes increased the expression of Ephrin-B2 in the cerebrovasculature and pericytes. Concomitant increases in cerebral neovascularization parameters including vascular density, tortuosity and branching density in diabetic rats were accompanied by deterioration of cognitive function. Inhibition of Ephrin-B2 expression in PCs significantly restored cerebral vascularization and improved cognitive functions. HG/Pal increased PC/EC angiogenic properties in co-culture. Silencing Ephrin-B2 in PCs significantly reduced PC migration and PC/EC co-culture angiogenic properties. This study emphasizes the significant contribution of PCs to the pathological neovascularization in diabetes. Our findings introduce Ephrin-B2 signaling as a promising therapeutic target to improve cerebrovascular integrity in diabetes.

Impact of Metabolic Diseases on Cerebral Circulation: Structural and Functional Consequences

Metabolic diseases including obesity, insulin resistance, and diabetes have profound effects on cerebral circulation. These diseases not only affect the architecture of cerebral blood arteries causing adverse remodeling, pathological neovascularization, and vasoregression but also alter the physiology of blood vessels resulting in compromised myogenic reactivity, neurovascular uncoupling, and endothelial dysfunction. Coupled with the disruption of blood brain barrier (BBB) integrity, changes in blood flow and microbleeds into the brain rapidly occur. This overview is organized into sections describing cerebrovascular architecture, physiology, and BBB in these diseases. In each section, we review these properties starting with larger arteries moving into smaller vessels. Where information is available, we review in the order of obesity, insulin resistance, and diabetes. We also tried to include information on biological variables such as the sex of the animal models noted since most of the information summarized was obtained using male animals. © 2018 American Physiological Society. Compr Physiol 8:773-799, 2018.

Azilsartan ameliorates diabetic cardiomyopathy in young db/db mice through the modulation of ACE-2/ANG 1-7/Mas receptor cascade

Hyperglycemia up-regulates intracellular angiotensin II (ANG-II) production in cardiac myocytes. This study investigated the hemodynamic and metabolic effects of azilsartan (AZL) treatment in a mouse model of diabetic cardiomyopathy and whether the cardioprotective effects of AZL are mediated by the angiotensin converting enzyme (ACE)-2/ANG 1-7/Mas receptor (R) cascade. Control db/+ and db/db mice (n=5 per group) were treated with vehicle or AZL (1 or 3mg/kg/d oral gavage) from the age of 8 to 16weeks. Echocardiography was then performed and myocardial protein levels of ACE-2, Mas R, AT₁R, AT₂R, osteopontin, connective tissue growth factor (CTGF), atrial natriuretic peptide (ANP) and nitrotyrosine were measured by Western blotting. Oxidative DNA damage and inflammatory markers were assessed by immunofluorescence of 8-hydroxy-2'-deoxyguanosine (8-OHdG), tumor necrosis factor (TNF)-α and interleukin 6 (IL-6). Compared with db/+ mice, the vehicle-treated db/db mice developed obesity, hyperglycemia, hyperinsulinemia and diastolic dysfunction along with cardiac hypertrophy and fibrosis. AZL treatment lowered blood pressure, fasting blood glucose and reduced peak plasma glucose during an oral glucose tolerance test. AZL-3 treatment resulted in a significant decrease in the expression of cytokines, oxidative DNA damage and cardiac dysfunction. Moreover, AZL-3 treatment significantly abrogated the downregulation of ACE-2 and Mas R protein levels in db/db mice. Furthermore, AZL treatment significantly reduced cardiac fibrosis, hypertrophy and their marker molecules (osteopontin, CTGF, TGF-β1 and ANP). Short-term treatment with AZL-3 reversed abnormal cardiac structural remodeling and partially improved glucose metabolism in db/db mice by modulating the ACE-2/ANG 1-7/Mas R pathway.

Azilsartan as a Potent Antihypertensive Drug with Possible Pleiotropic Cardiometabolic Effects: A Review Study

Background: Hypertension related cardiovascular (CV) complications could be amplified by the presence of metabolic co-morbidities. Azilsartan medoxomil (AZL-M) is the eighth approved member of angiotensin II receptor blockers (ARBs), a drug class of high priority in the management of hypertensive subjects with diabetes mellitus type II (DMII).

Methods: Under this prism, we performed a systematic review of the literature for all relevant articles in order to evaluate the efficacy, safety, and possible clinical role of AZL-M in hypertensive diabetic patients.

Results: AZL-M was found to be more effective in terms of reducing indices of blood pressure over alternative ARBs or angiotensin-converting enzyme (ACE) inhibitors with minimal side effects. Preclinical studies have established pleiotropic effects for AZL-M beyond its primary antihypertensive role through differential gene expression, up-regulation of membrane receptors and favorable effect on selective intracellular biochemical and pro-atherosclerotic pathways.

Conclusion: Indirect but accumulating evidence from recent literature supports the efficacy and safety of AZL-M among diabetic patients. However, no clinical data exist to date that evince a beneficial role of AZL-M in patients with metabolic disorders on top of its antihypertensive effect. Further clinical studies are warranted to assess the pleiotropic cardiometabolic benefits of AZL-M that are derived from preclinical research.

Angiotensin II type 1 receptor antagonists in animal models of vascular, cardiac, metabolic and renal disease

We have reviewed the effects of angiotensin II type 1 receptor antagonists (ARBs) in various animal models of hypertension, atherosclerosis, cardiac function, hypertrophy and fibrosis, glucose and lipid metabolism, and renal function and morphology. Those of azilsartan and telmisartan have been included comprehensively whereas those of other ARBs have been included systematically but without intention of completeness. ARBs as a class lower blood pressure in established hypertension and prevent hypertension development in all applicable animal models except those with a markedly suppressed renin-angiotensin system; blood pressure lowering even persists for a considerable time after discontinuation of treatment. This translates into a reduced mortality, particularly in models exhibiting marked hypertension. The retrieved data on vascular, cardiac and renal function and morphology as well as on glucose and lipid metabolism are discussed to address three main questions: 1. Can ARB effects on blood vessels, heart, kidney and metabolic function be explained by blood pressure lowering alone or are they additionally directly related to blockade of the renin-angiotensin system? 2. Are they shared by other inhibitors of the renin-angiotensin system, e.g. angiotensin converting enzyme inhibitors? 3. Are some effects specific for one or more compounds within the ARB class? Taken together these data profile ARBs as a drug class with unique properties that have beneficial effects far beyond those on blood pressure reduction and, in some cases distinct from those of angiotensin converting enzyme inhibitors. The clinical relevance of angiotensin receptor-independent effects of some ARBs remains to be determined.

Azilsartan medoxomil in the management of hypertension: an evidence-based review of its place in therapy

Background

Azilsartan (AZI) is a relatively new angiotensin receptor blocker available for the treatment of any stage of hypertension, which was eventually given in combination with chlorthalidone (CLT).

Objective

To review pharmacology and clinical role of AZI monotherapy and AZI/CLT or AZI/amlodipine combination therapies for hypertension management.

Methods

PubMed, Embase, and Cochrane Library were searched using search terms “ azilsartan”, “chlorthalidone,” “pharmacology,” “pharmacokinetics,” “pharmacodynamics,” “pharmacoeconomics,” and “cost-effectiveness.” To obtain other relevant information, US Food and Drug Association as well as manufacturer prescribing information were also reviewed.

Results

Randomized controlled trials demonstrated AZI to be superior to other sartans, such as valsartan, olmesartan, and candesartan, in terms of 24-hour ambulatory blood pressure monitoring (ABPM) reduction with respect. That beneficial effect of azilsartan was also associated with similar safety profiles. When compared to other antihypertensive drugs, azilsartan was found to be superior to any angiotensin-converting enzyme inhibitor, including ramipril, in terms of ABPM results, and noninferior to amlodipine in terms of sleep-BP control. The association of AZI and CLT was then found to be superior to other sartans + thiazide combination therapies in terms of both BP lowering and goal achievement. The combination of AZI and amlodipine has also been tested in clinical trials, but compared only with placebo, demonstrating its superiority in terms of efficacy and similarity in terms of safety.

Conclusion

Azilsartan is a safe and effective treatment option for every stage of hypertension, both alone or in fixed-dose combination tablets with chlorthalidone or amlodipine. Beneficial effects of AZI were also noted in patients with any degree of renal impairment. In addition, safety profiles of AZI were similar to that of the placebo.