AT1 receptor blocker inhibits HMGB1 expression in pressure overload-induced acute cardiac dysfunction by suppressing the MAPK/NF-κB signaling pathway.

BACKGROUND: High-mobility group box 1 (HMGB1) expression not only peaks during the early phase of pressure overload (PO), but also serves a role in the pathogenesis of PO-induced cardiac remodeling. Meanwhile, angiotensin II type 1 (AT1) receptor blockers reverse PO-induced cardiac remodeling and repress the secretion of inflammatory factors. However, whether AT1 receptor inhibitors decrease HMGB1 expression in the early stages of PO remains unknown. MATERIALS AND METHODS: PO mouse models were established using transverse aortic constriction (TAC), in which losartan was administrated. Transthoracic echocardiography was performed 3 days after the operation, and serum and cardiac HMGB1 expression, as well as the expression levels of related proteins were measured. RESULTS: PO-induced acute cardiac dysfunction was observed 3 days after TAC, and was subsequently slightly, but not significantly relieved by losartan. The expression levels of HMGB1, tumor necrosis factor-α and interleukin-6 in both the serum and myocardium were upregulated in response to TAC, while they were significantly reduced by losartan. Moreover, the phosphorylation of extracellular signal-regulated kinases, p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) in the myocardium were significantly increased under PO, and this was also prevented by losartan. CONCLUSION: These data suggest that losartan may downregulate the expression of HMGB1 in acute cardiac dysfunction induced by PO by inhibiting the MAPKs/NF-κB signaling pathway, which indicates a novel beneficial role of AT1 receptor antagonists in ameliorating cardiac remodeling under PO.

Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers: potential allies in the COVID-19 pandemic instead of a threat?

Angiotensin-converting enzyme 2 (ACE2) is the leading player of the protective renin-angiotensin system (RAS) pathway but also the entry receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). RAS inhibitors seemed to interfere with the ACE2 receptor, and their safety was addressed in COVID-19 patients. Pedrosa et al. (Clin. Sci. (Lond.) (2021), 135, 465-481) showed in rats that captopril and candesartan up-regulated ACE2 expression and the protective RAS pathway in lung tissue. In culture of pneumocytes, the captopril/candesartan-induced ACE2 up-regulation was associated with inhibition of ADAM17 activity, counterbalancing increased ACE2 expression, which was associated with reduced SARS-CoV-2 spike protein entry. If confirmed in humans, these results could become the pathophysiological background for justifying RAS inhibitors as cornerstone cardiovascular protectives even during COVID-19 pandemic.

Role of the renin-angiotensin-aldosterone system in bone metabolism.

With the acceleration of population aging, the incidence of osteoporosis has gradually increased, and osteoporosis and fractures caused by osteoporosis have gradually become a serious social public health problem. The classic role of the renin-angiotensin-aldosterone system (RAAS) is to keep blood pressure stable. However, as the components of RAAS were found in bone tissues, their functions of stimulating osteoclast formation and inhibiting osteoblast activity thus inducing bone loss have gradually emerged. RAAS blockers can prevent osteoporotic fractures which may be related to angiotensin type 1 (AT1) receptor, osteoprotegerin (OPG)/nuclear factor-κB ligand (RANKL), and angiotensin-converting enzyme 2 (ACE2)/angiotensin (1-7) (Ang (1-7))/G protein-coupled receptor (Mas) cascade. However, some studies suggest that RAAS blockers do not prevent osteoporotic fractures. This article reviews the effects of RAAS and RAAS inhibitors on bone metabolism and provides new ideas for the prevention of osteoporosis.

Renin-angiotensin system inhibition in COVID-19 patients.

Angiotensin-converting enzyme (ACE) inhibitors (ACEIs) and angiotensin II type­1 receptor blockers (ARBs) are among the most widely prescribed drugs for the treatment of arterial hypertension, heart failure and chronic kidney disease. A number of studies, mainly in animals and not involving the lungs, have indicated that these drugs can increase expression of angiotensin-converting enzyme 2 (ACE2). ACE2 is the cell entry receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19) that is currently battering the globe. This has led to the hypothesis that use of ACEIs and ARBs may increase the risk of developing severe COVID-19. In this point of view paper, possible scenarios regarding the impact of ACEI/ARB pharmacotherapy on COVID-19 are discussed in relation to the currently available evidence. Although further research on the influence of blood-pressure-lowering drugs, including those not targeting the renin-angiotensin system, is warranted, there are presently no compelling clinical data showing that ACEIs and ARBs increase the likelihood of contracting COVID-19 or worsen the outcome of SARS-CoV­2 infections. Thus, unless contraindicated, use of ACEIs/ARBs in COVID-19 patients should be continued in line with the recent recommendations of medical societies.

Combining probiotics and an angiotensin-II type 1 receptor blocker has beneficial effects on hepatic fibrogenesis in a rat model of non-alcoholic steatohepatitis.

AIM: Intestinal endotoxin is important for the progression of non-alcoholic steatohepatitis (NASH). Circulating endotoxin levels are elevated in most animal models of diet-induced non-alcoholic fatty liver disease (NAFLD) and NASH. Furthermore, plasma endotoxin levels are significantly higher in NAFLD patients, which is associated with small intestinal bacterial overgrowth and increased intestinal permeability. By improving the gut microbiota environment and restoring gut-barrier functions, probiotics are effective for NASH treatment in animal models. It is also widely known that hepatic fibrosis and suppression of activated hepatic stellate cells (Ac-HSCs) can be attenuated using an angiotensin-II type 1 receptor blocker (ARB). We thus evaluated the effect of combination probiotics and ARB treatment on liver fibrosis using a rat model of NASH. METHODS: Fisher 344 rats were fed a choline-deficient/L-amino acid-defined (CDAA) diet for 8 weeks to generate the NASH model. Animals were divided into ARB, probiotics, and ARB plus probiotics groups. Therapeutic efficacy was assessed by evaluating liver fibrosis, the lipopolysaccharide Toll-like receptor (TLR)4 regulatory cascade, and intestinal barrier function. RESULTS: Both probiotics and ARB inhibited liver fibrosis, with concomitant HSC activation and suppression of liver-specific transforming growth factor-ß and TLR4 expression. Probiotics reduced intestinal permeability by rescuing zonula occludens-1 disruption induced by the CDAA diet. Angiotensin-II type 1 receptor blocker was found to directly suppress Ac-HSCs. CONCLUSIONS: Probiotics and ARB are effective in suppressing liver fibrosis through different mechanisms. Currently both drugs are in clinical use; therefore, the combination of probiotics and ARB is a promising new therapy for NASH.

Randomized trial of an increased dose of calcium channel blocker or angiotensin II type 1 receptor blocker as an add-on intensive depressor therapy in type 2 diabetes mellitus patients with uncontrolled essential hypertension: the ACADEMIE Study.

There is a lack of data on how to treat hypertensive patients with diabetes when treatment with medium doses of calcium channel blocker and angiotensin II type 1 receptor blocker (ARB) is insufficient to achieve the target blood pressure (BP). A total of 121 participants with type 2 diabetes and uncontrolled essential hypertension, who were receiving medium doses of amlodipine (5 mg/day) and ARB, were enrolled. Participants were randomized to receive either a high dose of amlodipine (10 mg/day) plus a medium dose of ARB (high-AML) or a medium dose of amlodipine (5 mg/day) plus a high dose of ARB (high-ARB). The depressor effects of these two regimens were monitored using a telemonitoring home BP-measuring system. Fifty-four patients were excluded after an observation period, and the remaining 67 eligible participants were randomized into the two groups; 42 which had a record of their home BP for analysis. The change in morning home systolic and diastolic BP was greater in the high-AML than in the high-ARB (systolic BP; - 7.9 mmHg vs. + 2.7 mmHg; p = 0.0002, diastolic BP; - 3.9 mmHg vs. + 0.6 mmHg; p = 0.0007). In addition, the home systolic and diastolic BP before going to bed and office systolic BP were significantly reduced from week 0 only in the high-AML. An increased dose of amlodipine, but not ARB, reduced home morning BP in hypertensive patients with type 2 diabetes who were already receiving combination therapy with medium doses of amlodipine and ARB.

Angiotensin II type 1 receptor blockers prevent aortic arterial stiffness in elderly patients with hypertension.

Backgrounds and aims: Increased arterial stiffness may increase cardiovascular morbidity and mortality. Angiotensin II type 1 receptor blockers (ARBs) are potentially useful in controlling the central blood pressure and arterial stiffness in mild to moderate essential hypertension, while the effects of ARBs in aged patients with essential hypertension are not entirely investigated. Methods: The carotid-femoral arterial pulse wave velocity (PWV) was measured in aged patients with essential hypertension. Results: In a cross-sectional study, PWV value was significantly higher in these old patients with essential hypertension, compared to patients without essential hypertension. In correlation analysis, PWV was associated positively with age, hypertension duration, and carotid atherosclerosis. However, there was no relationship between PWV and gender in aged patients with essential hypertension. In a perspective study, 6-12 months administration of ARBs (losartan, 50 mg/day; telmisartan, 40 mg/day; valsartan 80 mg/day; irbesartan, 150 mg/day) remarkably reduced PWV in aged patients with essential hypertension. Regression analyses of multiple factors indicated that the effects of ARBs on arterial stiffness were not associated with the reduction of blood pressure. Conclusion: ARB treatment is a negative risk factor of arterial stiffness in aged patients with essential hypertension.

Telmisartan Inhibits Cell Proliferation and Tumor Growth of Esophageal Squamous Cell Carcinoma by Inducing S-Phase Arrest In Vitro and In Vivo.

Esophageal squamous cell carcinoma (ESCC) is the most common primary esophageal malignancy. Telmisartan, an angiotensin II type 1 (AT1) receptor blocker (ARB) and a widely used antihypertensive, has been shown to inhibit proliferation of various cancer types. This study evaluated the effects of telmisartan on human ESCC cell proliferation in vitro and in vivo and sought to identify the microRNAs (miRNAs) involved in these antitumor effects. We examined the effects of telmisartan on three human ESCC cell lines (KYSE150, KYSE180, and KYSE850). Telmisartan inhibited proliferation of these three cell lines by inducing S-phase arrest, which was accompanied by decreased expression of cyclin A2, cyclin-dependent kinase 2, and other cell cycle-related proteins. Additionally, telmisartan reduced levels of phosphorylated ErbB3 and thrombospondin-1 in KYSE180 cells. Furthermore, expression of miRNAs was remarkably altered by telmisartan in vitro. Telmisartan also inhibited tumor growth in vivo in a xenograft mouse model. In conclusion, telmisartan inhibited cell proliferation and tumor growth in ESCC cells by inducing cell-cycle arrest.

Silencing VEGF-B Diminishes the Neuroprotective Effect of Candesartan Treatment After Experimental Focal Cerebral Ischemia.

The pro-survival effect of VEGF-B has been documented in different in vivo and in vitro models. We have previously shown an enhanced VEGF-B expression in response to candesartan treatment after focal cerebral ischemia. In this study, we aimed to silence VEGF-B expression to assess its contribution to candesartan's benefit on stroke outcome. Silencing VEGF-B expression was achieved by bilateral intracerebroventricular injections of lentiviral particles containing short hairpin RNA (shRNA) against VEGF-B. Two weeks after lentiviral injections, rats were subjected to either 90 min or 3 h of middle cerebral artery occlusion (MCAO) and randomized to intravenous candesartan (1 mg/kg) or saline at reperfusion. Animals were sacrificed at 24 or 72 h and brains were collected and analyzed for hemoglobin (Hb) excess and infarct size, respectively. Functional outcome at 24, 48 and 72 h was assessed blindly. Candesartan treatment improved neurobehavioral and motor function, and decreased infarct size and Hb. While silencing VEGF-B expression diminished candesartan's neuroprotective effect, candesartan-mediated vascular protection was maintained even in the absence of VEGF-B suggesting that this growth factor is not the mediator of candesartan's vascular protective effects. However, VEGF-B is a mediator of neuroprotection achieved by candesartan and represents a potential drug target to improve stroke outcome. Further studies are needed to elucidate the underlying molecular mechanisms of VEGF-B in neuroprotection and recovery after ischemic stroke.

Comparison of Efficacy and Safety of Azilsartan and Olmesartan in Patients With Essential Hypertension.

Many patients still have high blood pressure (BP) after treatment with angiotensin II type 1 (AT1) receptor blockers (ARBs). We compared the efficacy and safety of azilsartan to those of olmesartan in a prospective randomized clinical trial. Sixty-four hypertensive patients who were treated with ARBs other than azilsartan and olmesartan were enrolled in this study. We randomly assigned patients to changeover from their prior ARBs to either azilsartan or olmesartan, and followed the patients for 3 months. Systolic BP (SBP) in the azilsartan group was significantly decreased at 3 months, and diastolic BP (DBP) and pulse rate (PR) in the olmesartan group showed significant reductions after 3 months. There were no significant differences in ΔSBP, ΔDBP, or ΔPR (Δ = the value at 3 months minus the value at 0 months) between the groups. Serum levels of creatinine (Cr), uric acid (UA), and potassium (K) in the azilsartan group significantly increased after 3 months. While the changes in Cr, UA, and K were within the respective normal ranges, ΔSBP was positively associated with ΔCr in the azilsartan group. In conclusion, there was no difference in the depressor effects of azilsartan and olmesartan, and there were no serious changes in biochemical parameters with azilsartan and olmesartan.

Effects of Tolvaptan With or Without the Pre-Administration of Renin-Angiotensin System Blockers in Hospitalized Patients With Acute Decompensated Heart Failure.

We examined whether tolvaptan combined with an angiotensin II receptor blocker (ARB) or angiotensin converting enzyme inhibitor (ACE-I) is more effective than tolvaptan alone in the treatment of patients with heart failure (HF). Sixty-five hospitalized patients with acute decompensated HF were included in this study. They were divided into 2 groups; an ARB/ACE-I group (n = 44, who received ARB or ACE-I before the use of tolvaptan) and a non-ARB/ACE-I group (n = 21). There were no significant differences in patient characteristics including medications at baseline between the non-ARB/ACE-I and ARB/ACE-I groups with the exception of the percentages of hypertension and ischemic heart disease. Urinary volume (UV) at baseline in the ARB/ACE-I group was slightly higher than that in the non-ARB/ACE-I group. The increase in UV after the use of tolvaptan in the non-ARB/ACE-I group was significantly higher than that in the ARB/ACE-I group. The cardiothoracic ratio and the reduction in body weight were similar between the groups after tolvaptan use. Finally, in a logistic regression analysis, a response to the use of tolvaptan was independently associated with the non-use of ARB/ACE-I, but not with age, gender, body mass index, loop diuretic, or human arterial natriuretic peptide. In conclusion, tolvaptan alone might induce an increase in UV in decompensated HF patients without ARB/ ACE-I, although the treatment of HF with ARB/ACE-I is the first choice strategy.

Peroxisome proliferator-activated receptor α-dependent renoprotection of murine kidney by irbesartan.

Activation of renal peroxisome proliferator-activated receptor α (PPARα) is renoprotective, but there is no safe PPARα activator for patients with chronic kidney disease (CKD). Studies have reported that irbesartan (Irbe), an angiotensin II receptor blocker (ARB) widely prescribed for CKD, activates hepatic PPARα. However, Irbe's renal PPARα-activating effects and the role of PPARα signalling in the renoprotective effects of Irbe are unknown. Herein, these aspects were investigated in healthy kidneys of wild-type (WT) and Ppara-null (KO) mice and in the murine protein-overload nephropathy (PON) model respectively. The results were compared with those of losartan (Los), another ARB that does not activate PPARα. PPARα and its target gene expression were significantly increased only in the kidneys of Irbe-treated WT mice and not in KO or Los-treated mice, suggesting that the renal PPARα-activating effect was Irbe-specific. Irbe-treated-PON-WT mice exhibited decreased urine protein excretion, tubular injury, oxidative stress (OS), and pro-inflammatory and apoptosis-stimulating responses, and they exhibited maintenance of fatty acid metabolism. Furthermore, the expression of PPARα and that of its target mRNAs encoding proteins involved in OS, pro-inflammatory responses, apoptosis and fatty acid metabolism was maintained upon Irbe treatment. These renoprotective effects of Irbe were reversed by the PPARα antagonist MK886 and were not detected in Irbe-treated-PON-KO mice. These results suggest that Irbe activates renal PPARα and that the resultant increased PPARα signalling mediates its renoprotective effects.

Efficacy and safety of two single-pill fixed-dose combinations of angiotensin II receptor blockers/calcium channel blockers in hypertensive patients (EXAMINER study).

BACKGROUND: There is some controversy regarding which single-pill fixed-dose combinations of angiotensin II type 1 receptor blockers (ARBs) and calcium channel blockers (CCBs) are effective at reducing blood pressure (BP). METHODS: Sixty hypertensive patients who received a single-pill fixed-dose combination of valsartan 80 mg/day and amlodipine 5 mg/day were enrolled (UMIN Registration 000013460). They were randomly divided into two treatment groups [single-pill fixed-dose combination therapy with valsartan 80 mg/day and amlodipine 5 mg/day (Val/Am group), or irbesartan 100 mg/day and amlodipine 5 mg/day (Irb/Am group)] and treated for 16 weeks. If the patient did not reach the target office BP at 8 weeks, they received double doses of amlodipine (10 mg/day). RESULTS: In the Irb/Am group, systolic BP (SBP) and diastolic BP (DBP) were significantly decreased at 16 weeks. There were no significant changes in SBP or DBP in the Val/Am group. In the Irb/Am group, serum uric acid (UA) was significantly decreased at 8 weeks and patients who had hyperuricemia showed significantly decreased serum UA at 16 weeks. In addition, the levels of triglycerides (TG) were significantly decreased at 16 weeks in the Irb/Am group. CONCLUSION: A single-pill fixed-dose combination therapy with irbesartan 100 mg/day and amlodipine 5 mg/day was superior to the combination of valsartan 80 mg/day and amlodipine 5 mg/day with respect to significant decreases in BP, serum UA and TG in patients with hypertension.

Comparison of direct renin inhibitor and angiotensin II receptor blocker on clinic and ambulatory blood pressure profiles in hypertension with chronic kidney disease.

We compared the therapeutic effects of aliskiren (direct renin inhibitor (DRI) group) with angiotensin II (Ang II) type 1 receptor blockers (ARBs) (ARB group) on clinic blood pressure (BP) and ambulatory BP in 36 hypertensive chronic kidney disease (CKD) patients. The baseline clinic BP levels and the after-treatment/baseline (A/B) ratios of clinic BP levels, estimated after 24-week treatment period, were similar in DRI group (n = 18) and ARB group (n = 18). With respect to the effects on ambulatory BP, the A/B ratios of the daytime and nighttime systolic BP in DRI group were significantly higher than those in ARB group. The A/B ratio of ankle-brachial pressure index after the study was higher in the DRI group compared with the ARB group. The results of the present study suggest that DRI therapy is not superior to ARB therapy in lowering ambulatory BP in hypertensive CKD patients, in spite of comparable clinic BP-lowering effects.

Comparison of aldosterone synthesis in adrenal cells, effect of various AT1 receptor blockers with or without atrial natriuretic peptide.

Bifunctional angiotensin II (Ang II) type 1 (AT1) receptor blockers (ARBs) that can block the activation of not only AT1 receptor, but also neprilysin, which metabolizes vasoactive peptides including atrial natriuretic peptide (ANP), are currently being developed. However, the usefulness of the inactivation of ANP in addition to the AT1 receptor with regard to aldosterone (Ald) synthesis is not yet clear. We evaluated the inhibitory effects of various ARBs combined with or without ANP on Ang II-induced adrenal Ald synthesis using a human adrenocortical cell line (NCI-H295R). Ang II increased Ald synthesis in a dose- and time-dependent manner. Ald synthesis induced by Ang II was completely blocked by azilsartan, but not PD123319 (AT2 receptor antagonist). CGP42112 AT2 receptor agonist did not affect Ald synthesis. While most ARBs block Ang II-induced Ald synthesis to different extents, azilsartan and olmesartan have similar blocking effects on Ald synthesis. The different effects of ARBs were particularly observed at 10(-7) and 10(-8 )M. ANP attenuated Ang II-induced Ald synthesis, and ANP-mediated attenuation of Ang II-induced Ald synthesis were blocked by inhibitors of G-protein signaling subtype 4 and protein kinase G. ANP (10(-8) and 10(-7 )M) without ARBs inhibited Ald synthesis, and the combination of ANP (10(-7 )M) and ARB (10(-8 )M) had an additive effect with respect to the inhibition of Ald synthesis. In conclusions, ARBs had differential effects on Ang II-induced Ald synthesis, and ANP may help to block Ald synthesis when the dose of ARB is not sufficient to block its secretion.

Azilsartan inhibits inflammation-triggered bone resorption and osteoclastogenesis in vivo via suppression of TNF-α expression in macrophages.

Introduction: Hypertension is a major risk factor for cardiovascular disease (CVD) and is associated with increased bone loss due to excessive activity of the local renin-angiotensin system (RAS). Angiotensinogen/Angiotensin (ANG) II/Angiotensin II type 1 receptor (AT1R) axis is considered as the core axis regulating RAS activity. Azilsartan is an FDA-approved selective AT1R antagonist that is used to treat hypertension. This study aimed to determine whether azilsartan affects formation of osteoclast, resorption of bone, and the expression of cytokines linked with osteoclastogenesis during lipopolysaccharide (LPS)-triggered inflammation in vivo. Methods: In vivo, following a 5-day supracalvarial injection of LPS or tumor necrosis factor-alpha (TNF-α) with or without azilsartan, the proportion of bone resorption and the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells, which are identified as osteoclasts on mice calvariae were counted. The mRNA expression levels of TRAP, cathepsin K, receptor activator of NF-κB ligand (RANKL), and TNF-α were also evaluated. In vitro, the effect of azilsartan (0, 0.01, 0.1, 1, and 10 µM) on RANKL and TNF-α-triggered osteoclastogenesis were investigated. Also, whether azilsartan restrains LPS-triggered TNF-α mRNA and protein expression in macrophages and RANKL expression in osteoblasts were assessed. Furthermore, western blotting for analysis of mitogen-activated protein kinases (MAPKs) signaling was conducted. Results: Azilsartan-treated calvariae exhibited significantly lower bone resorption and osteoclastogenesis than those treated with LPS alone. In vivo, LPS with azilsartan administration resulted in lower levels of receptor activator of RANKL and TNF-α mRNA expression than LPS administration alone. Nevertheless, azilsartan did not show inhibitory effect on RANKL- and TNF-α-triggered osteoclastogenesis in vitro. Compared to macrophages treated with LPS, TNF-α mRNA and protein levels were lower in macrophages treated by LPS with azilsartan. In contrast, RANKL mRNA and protein expression levels in osteoblasts were the same in cells co-treated with azilsartan and LPS and those exposed to LPS only. Furthermore, azilsartan suppressed LPS-triggered MAPKs signaling pathway in macrophages. After 5-day supracalvarial injection, there is no difference between TNF-α injection group and TNF-α with azilsartan injection group. Conclusion: These findings imply that azilsartan prevents LPS-triggered TNF-α production in macrophages, which in turn prevents LPS-Triggered osteoclast formation and bone resorption in vivo.

Angiotensin II Type 1 Receptor Blocker Prevents Abdominal Aortic Aneurysm Progression in Osteoprotegerin-Deficient Mice via Upregulation of Angiotensin (1-7).

Background Angiotensin II type 1 receptor blockers (ARBs) have been shown to limit the growth of abdominal aortic aneurysm (AAA), but their efficacy is controversial. This study aimed to investigate the molecular mechanism underlying the protective effect of ARBs against AAA progression. Methods and Results Olmesartan, an ARB, was administered to wild-type and osteoprotegerin-knockout (Opg-KO) mice starting 2 weeks before direct application of CaCl2 to aortas to induce AAA. The protective effect of olmesartan against AAA in wild-type and Opg-KO mice was compared at 6 weeks after AAA induction. Olmesartan prevented AAA progression in Opg-KO mice, including excessive aortic dilatation and collapse of tunica media, but not in wild-type mice. Deficiency of the Opg gene is known to cause excessive activation of the tumor necrosis factor-related apoptosis-inducing ligand-induced c-Jun N-terminal kinase/matrix metalloproteinase 9 pathway, resulting in prolonged AAA progression. Olmesartan attenuated the upregulation of phosphorylated c-Jun N-terminal kinase and matrix metalloproteinase 9 expression in the aortic wall of Opg-KO mice. In cultured vascular smooth muscle cells, tumor necrosis factor-related apoptosis-inducing ligand-induced c-Jun N-terminal kinase phosphorylation and matrix metalloproteinase 9 expression were inhibited by angiotensin (1-7), the circulating levels of which are increased by ARBs. Furthermore, administering an angiotensin (1-7) antagonist to Opg-KO mice diminished the protective effect of olmesartan against AAA progression. Conclusions Olmesartan prevented AAA progression in Opg-KO mice by upregulating angiotensin (1-7), suggesting that angiotensin (1-7) may be a key factor that mediates the protective effect of ARBs.

Valsartan Protects in High Fat Diet During Ischemic Reperfusion Injury.

AIM: The study investigates the effect of Valsartan, an Angiotensin II type 1 receptor blocker (ARB), on the blunted neuroprotective response of ischemic post-conditioning (iPoCo) in rats subjected to High Fat Diet (HFD). BACKGROUND: The neuroprotective response of iPoCo is blunted in conditions of vascular endothelial dysfunction (ED) associated with hypercholesterolemia, diabetes, hypertension, etc. Objectives: The study was undertaken to investigate the effect of Valsartan, an ARB, on the blunted neuroprotective response of iPoCo in rats subjected to HFD. METHODS: Wistar rats were subjected to HFD for 56 days. The cerebral ischemic injury was induced by bilateral common carotid artery occlusion (BCCAO) for 12 min followed by reperfusion of 24 hrs. iPoCo was induced by three preceding cycles of ischemia and reperfusion lasting 1 min each given immediately after BCCAO at the onset of prolonged reperfusion. The extent of the injury was assessed in terms of memory impairment using the Morris Water Maze test (MWM), sensorimotor disturbance using the neurological severity score (NSS), and cerebral infarct size using triphenyl tetrazolium chloride staining. Series of biochemical estimations including brain thiobarbituric acid reactive species (TBARS); reduced glutathione (GSH); myeloperoxidase (MPO); tumor necrosis factor-α (TNF-α); Nrf-2 and serum cholesterol, serum nitrite levels were performed. RESULTS: BCCAO produced significant cerebral injury indicated by increased cerebral infarct size, memory impairment, increased NSS, and various biochemical alterations (increased cholesterol, TBARS, MPO, TNF-α, Nrf-2, and decreased nitrite and GSH levels). Significant neutrophil infiltration was also observed. iPoCo attenuated BCCAO-induced injury with respect to the above parameters in normal rats. The protective response of iPoCo was lost in HFD-treated rats. Treatment of Valsartan attenuated cerebral injury, potentiated the neuroprotective response of iPoCo in normal rats, and also restored the blunted neuroprotective effect of iPoCo in HFD-treated rats along with enhanced Nrf-2 levels. CONCLUSION: Valsartan exerted a neuroprotective effect by virtue of its multiple actions with a crucial role of Nrf2 activation.

Fimasartan Ameliorates Deteriorations in Glucose Metabolism in a High Glucose State by Regulating Skeletal Muscle and Liver Cells.

PURPOSE: Since diabetes and hypertension frequently occur together, it is thought that these conditions may have a common pathogenesis. This study was designed to evaluate the anti-diabetic function of the anti-hypertensive drug fimasartan on C2C12 mouse skeletal muscle and HepG2 human liver cells in a high glucose state. MATERIALS AND METHODS: The anti-diabetic effects and mechanism of fimasartan were identified using Western blot, glucose uptake tests, oxygen consumption rate (OCR) analysis, adenosine 5'-triphosphate (ATP) enzyme-linked immunosorbent assay (ELISA), and immunofluorescence staining for diabetic biomarkers in C2C12 cells. Protein biomarkers for glycogenolysis and glycogenesis were evaluated by Western blotting and ELISA in HepG2 cells. RESULTS: The protein levels of phosphorylated 5' adenosine monophosphate-activated protein kinase (p-AMPK), p-AKT, insulin receptor substrate-1 (IRS-1), and glucose transporter type 4 (Glut4) were elevated in C2C12 cells treated with fimasartan. These increases were reversed by peroxisome proliferator-activated receptor delta (PPARδ) antagonist. ATP, OCR, and glucose uptake were increased in cells treated with 200 µM fimasartan. Protein levels of glycogen phosphorylase, glucose synthase, phosphorylated glycogen synthase, and glycogen synthase kinase-3 (GSK-3) were decreased in HepG2 cells treated with fimasartan. However, these effects were reversed following the addition of the PPARδ antagonist GSK0660. CONCLUSION: In conclusion, fimasartan ameliorates deteriorations in glucose metabolism as a result of a high glucose state by regulating PPARδ in skeletal muscle and liver cells.

MicroRNA profiles following telmisartan treatment in pancreatic ductal adenocarcinoma cells.

Background: Pancreatic ductal adenocarcinoma (PDAC) is the most devastating of all cancers with an extremely poor prognosis. It has few effective and reliable therapeutic strategies. Telmisartan, a widely used antihypertensive drug, is an angiotensin II type 1 (AT1) receptor blocker (ARB). Telmisartan inhibits cancer cell proliferation, but the underlying mechanisms in PDAC, remain unknown. Material and Methods: In the present study, we evaluated the effects of telmisartan on human PDAC cell proliferation in vitro. We assessed the effects of telmisartan on human PDAC cells using the cell lines PK-1 and PANC-1. Results: Telmisartan inhibited the proliferation of these cells via blockade of the G0 to G1 cell cycle transition. This was accompanied by a strong decrease in cyclin D1. Telmisartan was also shown by receptor tyrosine kinase and angiogenesis arrays to reduce the phosphorylation of epidermal growth factor receptor (EGFR), and miRNA expression was markedly altered by telmisartan in PK-1 cells. Conclusion: In conclusion, telmisartan inhibits human PDAC cell proliferation by inducing cell cycle arrest. Furthermore, telmisartan significantly altered miRNA expression in vitro. Taken together, our study demonstrated the therapeutic potential of telmisartan and provides molecular mechanistic insights into its anti-tumor effect on PDAC cells.