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The Libyan Strawberry, Arbutus pavarii Pampan (ARB), is an endemic Jebel Akhdar plant used for traditional medicine. This study presents the antioxidant and hepatoprotective properties of ARB fruit-extract. ARB phytochemical analysis indicated the presence of 354.54 GAE and 36.2 RE of the phenolics and flavonoids. LC-MS analysis identified 35 compounds belonging to phenolic acids, procyanidins, and flavonoid glycosides. Gallic acid, procyanidin dimer B3, β-type procyanidin trimer C, and quercetin-3-O-glucoside were the major constituents of the plant extract. ARB administration to paracetamol (PAR)-intoxicated rats reduced serum ALT, AST, bilirubin, hepatic tissue MDA and proinflammatory markers; TNF-α and IL-6 with an increase in tissue GSH level and SOD activity. Histological and immunohistochemical studies revealed that ARB restored the liver histology and significantly reduced the tissue expression of caspase 3, IL-1B, and NF-KB in PAR-induced liver damage. Docking analysis disclosed good binding affinities of some compounds with XO, COX-1, 5-LOX, and PI3K.

Sarcopenia is associated with mortality in patients with nonalcoholic steatohepatitis (NASH). Angiotensin II receptor blocker (ARB) has been suggested to prevent sarcopenia, but reports on its effect on NASH-derived skeletal muscle atrophy in conjunction with insulin-like growth factor 1 (IGF-1)-mediated muscle homeostasis are few. Our aim was to examine the combined effect of the ARB losartan and IGF-1 replacement on skeletal muscle atrophy in a methionine-choline deficient (MCD) diet-fed murine steatohepatitis model. The MCD-fed mice developed steatohepatitis and skeletal muscle atrophy, as indicated by the reduction of psoas muscle mass and attenuation of forelimb and hindlimb grip strength. Significantly suppressed steatohepatitis and skeletal muscle atrophy was observed after single treatment with ARB or IGF-1, and these effects were augmented after combination treatment. Treatment with ARB and IGF-1 effectively inhibited ubiquitin proteasome-mediated protein degradation by reducing forkhead box protein O1 (FOXO1) and FOXO3a transcriptional activity in the skeletal muscle. Combined ARB and IGF-1 decreased the intramuscular expression of proinflammatory cytokines (i.e., TNFα, IL6, and IL1β) and increased the Trolox equivalent antioxidant capacity and antioxidant enzymes (CAT, GPX1, SOD2, and CYTB). This antioxidant effect was based on downregulation of NADPH oxidase (NOX) 2, normalization of mitochondrial biogenesis and dynamics. Moreover, ARB increased the hepatic and plasma IGF-1 levels and improved steatohepatitis, leading to enhanced skeletal muscle protein synthesis mediated by IGF-1/ AKT/ mechanistic target of rapamycin signaling. Collectively, combined ARB and IGF-1 replacement could be a promising new therapeutic target for NASH-derived skeletal muscle wasting., Competing Interests: Declaration of competing interest No potential conflicts of interest were disclosed by all authors., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In diabetes, increased oxidative stress and impaired trace element metabolism play an important role in the pathogenesis of diabetic nephropathy. The objective of this research was to examine the outcomes of blocking the renin-angiotensin system, using either the angiotensin-converting enzyme inhibitor (ACEI), perindopril, or the angiotensin II type 1 (AT1) receptor blocker, irbesartan, on oxidative stress and trace element levels such as Zn, Mg, Cu, and Fe in the kidneys of diabetic rats that had been induced with streptozotocin. Thirty-two Wistar albino male rats were equally divided into four groups. The first group was used as a control. The second group of rats developed diabetes after receiving a single intraperitoneal dose of STZ. The third and fourth groups of rats had STZ-induced diabetes and received daily dosages of irbesartan (15 mg/kg b.w/day) and perindopril (6 mg/kg b.w/day) treatment, respectively. Biochemical analysis of the kidneys showed a distinct increase in oxidative stress, indicated by heightened levels of malondialdehyde (MDA) and decreased superoxide dismutase (SOD) activities, as well as reduced glutathione (GSH) levels in the kidneys of diabetic rats. In the kidneys of diabetic rats, the mean levels of Fe and Cu were found to be significantly higher than those of the control group. Additionally, the mean levels of Zn and Mg were significantly lower in the diabetic rats compared to the control rats. Both perindopril and irbesartan decreased significantly MDA content and increased SOD activities and GSH levels in the kidneys of rats with diabetes. The Zn and Mg concentrations in the kidneys of diabetic rats treated with perindopril and irbesartan were markedly higher than in untreated STZ-diabetic rats, while the Cu and Fe concentrations were significantly lower. The urinary excretion of rats treated with perindopril and irbesartan showed a pronounced increase in Cu levels, along with a significant reduction in Zn and Mg levels. Although diabetic rats demonstrated degenerative morphological alterations in their kidneys, both therapies also improved diabetes-induced histopathological modifications in the kidneys. Finally, the present results suggest that manipulating the levels of Zn, Mg, Cu, and Fe - either through ACE inhibition or by blocking AT1 receptors - could be advantageous in reducing lipid peroxidation and increasing antioxidant concentration in the kidneys of diabetic rats., Competing Interests: Declaration of competing interest No conflicts of interest, financial or otherwise are declared by the author(s). All authors approved the final manuscript., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Microplastics could act as vectors for the transport of harmful bacteria, such as pathogens and antibiotic resistance bacteria (ARB), but their combined effects have not been reported yet. Here, ARB Shigella flexneri with sulfonamides resistance and micro-polystyrene (micro-PS) were used to investigate their possible combined effects on the growth and expression of functional genes in Daphnia magna. Results showed that micro-PS colonized with S. flexneri were ingested by D. magna and blocked in their intestine after 24 h exposure. Changes were observed in the life history and morphology of D. magna, as well as the expression of functional genes in all treatments, but with no difference in the survival rate. We also determined the expression of six functional genes involved in energy and metabolism (arginine kinase, AK) and oxidative stress response (thioredoxin reductase, TRxR, catalase, CAT, and glutathione S-transferases, GSTs), as well as in growth, development and reproduction (vitellogenin, Vtg1 and ecdysone receptor, EcR). AK and Vtg1 did not show significant differences, however, EcR was down-regulated and the other three genes (TRxR, CAT, GSTs) were up-regulated in the combined-treated group. Antibiotic resistance gene (ARGs) sul1 was detected when exposed to micro-PS colonized with S. flexneri., suggesting that D. magna could acquire resistance genes through microplastic biofilms. These results indicated that MPs could act as a carrier of ARB to transfer ARGs into D. magna, and affect the life history, morphology, and the expression of related functional genes of D. magna, to adapt to the stress caused by MPs and ARB., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Azo dyes wastewater contains refractory pollutant and nitrogen, which threatens human health and ecological environment when discharged into environment directly. Electron shuttle (ES) is able to participate in the extracellular electron transfer, and thus enhances the removal efficiency of refractory pollutant. However, the continuous dosing of soluble ES would rise operation cost and cause contamination inevitably. In this study, a type of insoluble ES (carbonylated graphene oxide (C-GO)) was developed and melt blended into polyethylene (PE) to prepare novel C-GO-modified suspended carriers. Compared to those of conventional carrier (31.60%), the surface active sites of novel C-GO-modified carrier increased to 52.95%. An integrated hydrolysis/acidification (HA, filled with C-GO-modified carrier) - anoxic/aerobic (AO, filled with clinoptilolite-modified carrier) process was applied to remove azo dye acid red B (ARB) and nitrogen simultaneously. ARB removal efficiency was significantly improved in the reactor filled with C-GO-modified carriers (HA2) compared to the reactor filled with conventional PE carriers (HA1) or activated sludge (HA0). Total nitrogen (TN) removal efficiency of the proposed process increased by 25.95-32.64% compared to the reactor filled with activated sludge. Moreover, the intermediates of ARB were identified by liquid chromatograph-mass spectrometer (LC-MS), and the degradation pathway of ARB through ES was proposed. C-GO-modified carriers induced ARB-removal-related bacterial enrichment (such as Chloroflexi, Lactivibrio, Longilinea, Bacteroidales and Anaerolineaceae). Besides, the relative abundance of denitrifiers and nitrifiers in the AO reactor filled with clinoptilolite-modified carrier was increased by 11.60% compared with activated sludge. Copy numbers of genes related to membrane transport, carbon/energy metabolism and nitrogen metabolism increased significantly on the surface-modified carriers. This study proposed an efficient approach for simultaneous azo dyes and nitrogen removal, showing potential in actual application., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The safe reuse of reclaimed water for agricultural irrigation has been considered as an alternative, feasible and sustainable option to address water scarcity. This work aims to validate the capability of the solar water photochemical process based on the synergistic effect between peroxymonosulfate (PMS) and natural solar radiation for actual urban wastewater (UWW) purification at a pilot plant scale using a solar Compound Parabolic Collector photo-reactor. The PMS/Solar process performance was assessed by monitoring simultaneously the inactivation of naturally occurring bacteria (Escherichia coli, Total coliforms, Enterococcus spp. and Pseudomonas spp.) as a potential tertiary treatment to fit the minimum bacterial requirements for UWW purification but also additional challenges have been in deep analysed simultaneously. In this regard, a global analysis including the degradation of three Contaminants of Emerging Concern (CECs) (Diclofenac-DCF, Sulfamethoxazole-SMX and Trimethoprim-TMP), the removal of antibiotic resistant elements, the residual toxicity and the treatment cost has been analysed. Different PMS concentrations (0-1 mM) were tested and an enhancement in the process performance was obtained with increasing oxidant load, obtaining the best results with 1 mM of PMS, at which detection limit (DL) of 2 CFU/mL was reached for all microbial targets after 15 min (1.1 kJ/L of accumulated solar UV-A radiation (Q UV )) and 80 % of CECs removal was reached after 27 min (2.0 kJ/L of Q UV ) of solar treatment time. Inactivation of naturally occurring antibiotic resistant bacteria (ARB) and removal of 16S rRNA and selected antibiotic resistance genes (ARGs) (i.e., intI1, sul1, qnrS, bla TEM , bla CTX-M32 , tetM) were also investigated. ARB was successfully inactivated to values below the DL, but the process was not able to completely remove ARGs. A total reduction of intI1 (30 %), 16S rRNA (19 %), sul1 (14 %), bla CTX-M32 (12 %), qnrS (10 %), bla TEM (8 %), and tetM (7 %), was obtained after 120 min (11.5 kJ/L of Q UV ). An absence of an eco and phytotoxic effect of treated samples was observed towards Aliivibrio fischeri and three seeds, respectively. Finally, an estimated treatment cost of 0.96 €/m 3 for the simultaneous UWW disinfection and decontamination demonstrates the promising capability of this solar treatment for UWW reclamation and reuse in agriculture, especially in areas with a high solar radiation incidence., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

The aim of this study was to investigate the effects of arbutin (ARB) administration on oxidative stress, inflammation, endoplasmic reticulum (ER) stress and apoptosis in an experimental testicular torsion/detorsion (T/D)-induced testicular injury model for the first time. A total of 24 male Sprague-Dawley rats were divided into four groups with six rats in each group: sham control, T/D, T/D+ARB (50 mg/kg) and T/D+ARB (100 mg/kg). Torsion and detorsion times were applied as 4 h and 2 h, respectively. The levels of lipid peroxidation [malondialdehyde (MDA)] and oxidative stress [total oxidant status (TOS) and total antioxidant status (TAS)] in testicular tissues were determined using colorimetric methods. The levels of DNA damage [8-hydroxy-2'-deoxyguanosine (8-OHdG)], antioxidant system [superoxide dismutase (SOD) and catalase (CAT)], pro-inflammatory cytokines [high mobility group box 1 (HMGB1), nuclear factor kappa B protein 65 (NF-κB p65), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and myeloperoxidase (MPO)], ER stress [78-kDa glucose-regulated protein (GRP78), activating transcription factor 6 (ATF6) and CCAAT-enhancer-binding protein homologous protein (CHOP)] and apoptosis (caspase-3) markers in testicular tissues were determined using commercial enzyme-linked immunosorbent assay (ELISA) kits. Johnsen's testicle scoring system was used for histological evaluation. In the T/D group, it was determined that statistically significant increasing in the levels of oxidative stress, inflammation, ER stress and apoptosis compared with sham control group (p < 0.05). ARB administrations statistically significantly restored testicular I/R damage in a dose dependent manner (p < 0.05). In addition, it was determined that the data of histological examinations supported the biochemical results. Our findings support the hypothesis that ARB may be used as a protective agent against T/D-induced testicular damage., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Cyclophosphamide (CP) is a potent anticancer drug widely employed in chemotherapy against various types of cancer. However, CP leads to toxicity to non-targeted organs, including the liver and this limits its clinical use. This study explored the role of arbutin (ARB) against CP-mediated oxidative and inflammatory reactions and hepatotoxicity. Rats were administered ARB (25 and 50 mg/kg) for 14 days and CP (150 mg/kg). CP triggered liver tissue injury with marked increase in serum AST, ALT, ALP, and bilirubin, and hepatic malondialdehyde (MDA) and nitric oxide (NO) coupled with diminution of GSH, SOD, catalase, and GPx. Liver NF-kB p65, NOS, IL-6, TNF-α, Bax and caspase-3 were upregulated by CP injection and IL-10 and Bcl-2 were decreased. ARB prevented liver injury, suppressed MDA, NO, NF-kB p65, inflammatory markers, Bax and caspase-3 in CP-treated rats. ARB restored antioxidants, IL-10 and Bcl-2, and enhanced Nrf2 and hemeoxygenase-1 (HO) both gene and protein in the liver of rats. In conclusion, these results pinpointed the protective role of ARB on oxidative and inflammatory reactions, apoptosis, and hepatotoxicity in rats. This hepatoprotective activity was linked to the ability of ARB to modulate Nrf2/HO-1 pathway., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Peritoneal dialysis (PD) is limited by reduced efficacy over time. We previously showed that a Janus kinase 1/2 inhibitor (JAK1/2i) reduced inflammation, hypervascularity and fibrosis induced by 4.25% dextrose dialysate (4.25%D) intraperitoneally (IP) infused for 10 days in rats with normal kidney function. JAK/STAT signalling mediates inflammatory pathways, including angiotensin signalling. We now tested the effect of long-term JAK1/2i and/or an angiotensin receptor blocker (ARB) on peritoneal membrane (PM) in polycystic kidneys (PCK) rats infused with 4.25%D., Methods: Except for controls, all PCK rats had a tunnelled PD catheter: (1) no infusions; (2) 4.25%D; (3) 4.25%D + JAK1/2i (5 mg/kg); (4) 4.25%D +losartan (5 mg/kg); and (5) 4.25%D + losartan +JAK1/2i (5 mg/kg each) IP BID × 16 weeks ( N = 5/group). PM VEGFR2 staining areas and submesothelial compact zone (SMCZ) width were morphometrically measured. Peritoneal equilibration testing measured peritoneal ultrafiltration (UF) by calculating dialysate glucose at time 0 and 90 min (D/D 0 glucose)., Results: 4.25%D caused hypervascularity, SMCZ widening, fibrosis and UF functional decline in PCK rats. Angiogenesis was significantly attenuated by JAK1/2i ± ARB but not by ARB monotherapy. Both treatments reduced SMCZ area. UF was preserved consistently by dual therapy ( p < 0.05) but with inconsistent responses by monotherapies., Conclusion: Long-term JAK1/2i ± ARB reduced angiogenesis and fibrosis, and the combination consistently maintained UF. In clinical practice, angiotensin inhibition has been advocated to maintain residual kidney function. Our study suggests that adding JAK1/2i to angiotensin inhibition may preserve PM structure and UF.

The metabolic syndrome has been associated to chronic peripheral inflammation and related with neuroinflammation and neurodegeneration, including Parkinson's disease. However, the responsible mechanisms are unclear. Previous studies have involved the brain renin-angiotensin system in progression of Parkinson's disease and the angiotensin receptor type 1 (AT1) has been recently revealed as a major marker of dopaminergic vulnerability in humans. Dysregulation of tissue renin-angiotensin system is a key common mechanism for all major components of metabolic syndrome. Circulating AT1 agonistic autoantibodies have been observed in several inflammation-related peripheral processes, and activation of AT1 receptors of endothelial cells, dopaminergic neurons and glial cells have been observed to disrupt endothelial blood -brain barrier and induce neurodegeneration, respectively. Using a rat model, we observed that metabolic syndrome induces overactivity of nigral pro-inflammatory renin-angiotensin system axis, leading to increase in oxidative stress and neuroinflammation and enhancing dopaminergic neurodegeneration, which was inhibited by treatment with AT1 receptor blockers (ARBs). In rats, metabolic syndrome induced the increase in circulating levels of LIGHT and other major pro-inflammatory cytokines, and 27-hydroxycholesterol. Furthermore, the rats showed a significant increase in serum levels of proinflammatory AT1 and angiotensin converting enzyme 2 (ACE2) autoantibodies, which correlated with levels of several metabolic syndrome parameters. We also found AT1 and ACE2 autoantibodies in the CSF of these rats. Effects of circulating autoantibodies were confirmed by chronic infusion of AT1 autoantibodies, which induced blood-brain barrier disruption, an increase in the pro-inflammatory renin-angiotensin system activity in the substantia nigra and a significant enhancement in dopaminergic neuron death in two different rat models of Parkinson's disease. Observations in the rat models, were analyzed in a cohort of parkinsonian and non-parkinsonian patients with or without metabolic syndrome. Non-parkinsonian patients with metabolic syndrome showed significantly higher levels of AT1 autoantibodies than non-parkinsonian patients without metabolic syndrome. However, there was no significant difference between parkinsonian patients with metabolic syndrome or without metabolic syndrome, which showed higher levels of AT1 autoantibodies than non-parkinsonian controls. This is consistent with our recent studies, showing significant increase of AT1 and ACE2 autoantibodies in parkinsonian patients, which was related to dopaminergic degeneration and neuroinflammation. Altogether may lead to a vicious circle enhancing the progression of the disease that may be inhibited by strategies against production of these autoantibodies or AT1 receptor blockers (ARBs)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Telmisartan and irbesartan are angiotensin II receptor blockers (ARBs) and reportedly stimulate adiponectin secretion from adipocytes via partial peroxisome proliferator-activated receptor γ (PPARγ) activation. However, quantitative evaluation among different ARBs has not been performed. Adiponectin exerts strong protection against a number of pathological events by suppressing cell death, inhibiting inflammation, and enhancing cell survival, while leptin promotes inflammation, oxidative stress, atherogenesis, and thrombosis. The aim of this study was to identify the most effective ARB enhancing adiponectin secretion without raising leptin secretion from human white adipocytes (HWAs). Among seven ARBs (azilsartan, candesartan, irbesartan, losartan, olmesartan, telmisartan, and valsartan), telmisartan was the most effective ARB for the increase of adiponectin secretion and irbesartan was the second, whereas the other ARBs at 1 µM had no effect on adiponectin secretion. GW9662, a PPARγ antagonist, completely blocked pioglitazone (PPARγ agonist)-induced adiponectin secretion and mRNA expression, whereas it unexpectedly blocked neither telmisartan- nor irbesartan-induced adiponectin secretion and mRNA expression but rather increased them. GW6471, PPARα antagonist, and siRNA for PPARα suppressed telmisartan- and irbesartan-induced adiponectin secretion, suggesting that PPARα is the main target of these ARBs to increase adiponectin secretion in HWAs. Leptin secretion was not affected by any ARBs at 1 µM and GW9662 significantly decreased the basal secretion of leptin, suggesting that basal leptin secretion is regulated in a PPARγ-dependent manner. We conclude that telmisartan is the most effective ARB to increase adiponectin secretion via PPARα without raising leptin secretion from HWAs.

Angiotensin receptor blockers have been reported to be beneficial to liver fibrosis, but the relevant molecular and cellular mechanisms remain unclear. We herein investigated whether low-dose angiotensin receptor blocker alleviated liver fibrosis through mechanotransduction regulation. Hydrostatic pressure-induced liver fibrosis model was established in mice by ligating partially the inferior vena cava, and then randomly received a very low dose of losartan (0.5 mg/kg) or placebo treatment for 8 weeks. We found that losartan administration interfered the expression of several mechanotransductive molecules, and effectively alleviated liver fibrosis. Using a commercial device, we further confirmed that ex vivo loading of hepatic stellate cells to 50 mmHg hydrostatic pressure for 24 h significantly upregulated RhoA, ROCK, AT1R, and p-MLC2, which was effectively attenuated by adding 10 nM losartan in medium. Our in vivo and ex vivo experimental data suggest that low-dose angiotensin receptor blockers may alleviate hydrostatic pressure-induced liver fibrosis by altering the mechanotransduction properties of hepatic stellate cells. NEW & NOTEWORTHY Our ex vivo and in vivo experiments clearly indicated that low-dose losartan alleviated liver fibrosis, likely by modulating the mechanotransduction properties of HSCs. Uncovering the biomechanical signaling pathway of ARB treatment on liver fibrosis will be helpful to develop novel molecular targeting therapy for liver diseases.

Scope: This study investigated the combined effect of the angiotensin II (AT-II) receptor blocker losartan and branched-chain amino acids (BCAAs) on skeletal muscle atrophy in rats with cirrhosis and steatohepatitis., Method and Results: Fischer 344 rats are fed a choline-deficient l-amino acid-defined (CDAA) diet for 12 weeks and treated with oral losartan (30 mg kg -1 day -1 ) and/or BCAAs (Aminoleban EN, 2500 mg kg -1 day -1 ). Treatment with losartan and BCAAs attenuated hepatic inflammation and fibrosis and improved skeletal muscle atrophy and strength in CDAA-fed rats. Both agents reduced intramuscular myostatin and pro-inflammatory cytokine levels, resulting in inhibition of the ubiquitin-proteasome system (UPS) through interference with the SMAD and nuclear factor-kappa B pathways, respectively. Losartan also augmented the BCAA-mediated increase of skeletal muscle mass by promoting insulin growth factor-I production and mitochondrial biogenesis. Moreover, losartan decreased the intramuscular expression of transcription factor EB (TFEB), a transcriptional inducer of E3 ubiquitin ligase regulated by AT-II. In vitro assays illustrated that losartan promoted mitochondrial biogenesis and reduced TFEB expression in AT-II-stimulated rat myocytes, thereby potentiating the inhibitory effects of BCAAs on the UPS and caspase-3 cleavage., Conclusion: These results indicate that this regimen could serve as a novel treatment for patients with sarcopenia and liver cirrhosis., (© 2021 Wiley-VCH GmbH.)

The AT 1 receptor, a major effector of the renin-angiotensin system, has been extensively studied in the context of cardiovascular and renal disease. Moreover, angiotensin receptor blockers, sartans, are among the most frequently prescribed drugs for the treatment of hypertension, chronic heart failure and chronic kidney disease. However, precise molecular insights into the structure of this important drug target have not been available until recently. In this context, seminal studies have now revealed exciting new insights into the structure and biased signaling of the receptor and may thus foster the development of novel therapeutic approaches to enhance the efficacy of pharmacological angiotensin receptor antagonism or to enable therapeutic induction of biased receptor activity. In this review, we will therefore highlight these and other seminal publications to summarize the current understanding of the tertiary structure, ligand binding properties and downstream signal transduction of the AT 1 receptor., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The renin-angiotensin-aldosterone system (RAAS) plays a major role in cardiovascular health and disease. Short-term RAAS activation controls water and salt retention and causes vasoconstriction, which are beneficial for maintaining cardiac output in low blood pressure and early stage heart failure. However, prolonged RAAS activation is detrimental, leading to structural remodeling and cardiac dysfunction. Natriuretic peptides (NPs) are activated to counterbalance the effect of RAAS and sympathetic nervous system by facilitating water and salt excretion and causing vasodilation. Neprilysin is a major NP-degrading enzyme that degrades multiple vaso-modulatory substances. Although the inhibition of neprilysin alone is not sufficient to counterbalance RAAS activation in cardiovascular diseases (e.g., hypertension and heart failure), a combination of angiotensin receptor blocker and neprilysin inhibitor (ARNI) was highly effective in several clinical trials and may modulate the risk of atrial and ventricular arrhythmias. This review summarizes the possible link between ARNI and cardiac arrhythmias and discusses potential underlying mechanisms, providing novel insights about the therapeutic role and safety profile of ARNI in the cardiovascular system.

Angiotensin-(1-5) [Ang-(1-5)], which is a metabolite of Ang-(1-7) catalyzed by angiotensin-converting enzyme, is a novel pentapeptide of the renin-angiotensin system. Ang-(1-7), Ang III and Ang IV have a cardio-protective effect via Mas receptor, Ang II type 2 receptor (AT 2 R) and AT 4 R, respectively. However, it is not clear whether Ang-(1-5) has cardio-protective effects. The aim of this study is to investigate whether Ang-(1-5) protects the heart against ischemia-reperfusion (I/R) injury. After sacrificing Sprague-Dawley rats, the hearts were perfused with Krebs-Henseleit buffer for a 20 min pre-ischemic period with and without Ang-(1-5) followed by 20 min global ischemia and 50 min reperfusion. Ang-(1-5) (1 μM) improved changes in post-ischemic left ventricular developed pressure (LVDP), ±dP/dt, and post-ischemic left ventricular end-diastolic pressure (LVEDP) induced by reperfusion compared to control hearts. Ang-(1-5) decreased myocardial infarct size and LDH activity, and increased coronary flow and the amount of atrial natriuretic peptide (ANP) in coronary effluent during reperfusion compared to control hearts. Pretreatment with Mas receptor antagonist but not with AT 1 R or AT 2 R antagonist attenuated the improvement of changes in I/R-induced ventricular hemodynamics by Ang-(1-5). Ang-(1-5) treatment decreased Bax, caspase-3 and caspase-9 protein levels, and increased Bcl-2 protein level, which were attenuated by A779 pretreatment. Ang-(1-5) treatment increased Mn-superoxide dismutase, catalase, and heme oxygenase-1 protein levels, which was attenuated by A779 pretreatment. These results suggest that the cardio-protective effects of Ang-(1-5) against I/R injury may be partly related to activating anti-oxidant and anti-apoptotic enzymes via Mas receptor., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) associates with a considerable high rate of mortality and represents currently the most important concern in global health. The risk of more severe clinical manifestation of COVID-19 is higher in males and steeply raised with age but also increased by the presence of chronic comorbidities. Among the latter, early reports suggested that arterial hypertension associates with higher susceptibility to SARS-CoV-2 infection, more severe course and increased COVID-19-related deaths. Furthermore, experimental studies suggested that key pathophysiological hypertension mechanisms, such as activation of the renin-angiotensin system (RAS), may play a role in COVID-19. In fact, ACE2 (angiotensin-converting-enzyme 2) is the pivotal receptor for SARS-CoV-2 to enter host cells and provides thus a link between COVID-19 and RAS. It was thus anticipated that drugs modulating the RAS including an upregulation of ACE2 may increase the risk for infection with SARS-CoV-2 and poorer outcomes in COVID-19. Since the use of RAS-blockers, ACE inhibitors or angiotensin receptor blockers, represents the backbone of recommended antihypertensive therapy and intense debate about their use in the COVID-19 pandemic has developed. Currently, a direct role of hypertension, independent of age and other comorbidities, as a risk factor for the SARS-COV-2 infection and COVID-19 outcome, particularly death, has not been established. Similarly, both current experimental and clinical studies do not support an unfavorable effect of RAS-blockers or other classes of first line blood pressure lowering drugs in COVID-19. Here, we review available data on the role of hypertension and its management on COVID-19. Conversely, some aspects as to how the COVID-19 affects hypertension management and impacts on future developments are also briefly discussed. COVID-19 has and continues to proof the critical importance of hypertension research to address questions that are important for global health.

A recently isolated osmo-tolerant yeast Candida tropicalis A1, which could decolorize various azo dyes under high-salinity conditions, was systematically characterized in the present study. Stimulating dye-decolorization effectiveness and osmo-tolerance of the yeast by static magnetic field (SMF) was investigated and transcriptomic responses of the yeast to SMF was analyzed to propose possible mechanisms. The results demonstrated that the yeast A1 effectively decolorized (≥ 97.50% within 12 h) and detoxified (from high toxicity to low toxicity within 24 h) 70 mg/L Acid Red B (ARB) under the optimized conditions through a series of steps including naphthalene-amidine bond cleavage, reductive or oxidative deamination/desulfurization, open-loop of hydroxy-substituted naphthalene or benzene and TCA cycle. Moreover, dye decolorization performance and osmo-tolerance of the yeast A1 were further improved by 24.6 mT SMF. Genes encoding high-affinity hexose/glucose transporter proteins and NADH-ubiquinone oxidoreductase were up-regulated by 24.6 mT SMF, which might be responsible for the increase of dye decolorization. Significant up-regulation of glycerol-3-phosphate dehydrogenase and cell wall protein RHD3 suggested that osmo-tolerance was enhanced by 24.6 mT SMF through promoting production and intracellular accumulation of glycerol as compatible solute, as well as regulation of cell wall component. In conclusion, 24.6 mT SMF led to the up-regulation of related genes resulting in enhanced dye biodegradation efficiency and osmo-tolerance of the yeast A1., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Organic anion transporter (OAT) 4, which is localized at the apical membrane of human renal proximal tubules, transports olmesartan, an angiotensin II receptor blocker (ARB). Many ARBs, including olmesartan, undergo partial tubular secretion as active forms, and inhibit OAT4-mediated uptake activity. Here, we examined the substrate recognition of various ARBs by OAT4 in order to assess whether OAT4 might be involved in the renal handling of ARBs. Concentration-dependent OAT4-mediated uptake of azilsartan, candesartan, carboxylosartan, losartan, and valsartan was observed with K m values of 6.6, 31, 7.2, 13, and 1.7 μM, respectively, in the absence of extracellular Cl - . In the presence of extracellular Cl - , OAT4-mediated uptake of dianionic ARBs (azilsartan, candesartan, carboxylosartan, and valsartan) was lower and reached a steady state faster than in the absence of extracellular Cl - . Thus, OAT4 is proposed to use extracellular Cl - as a counterpart for anion efflux. Our results suggest that OAT4 may play a role in the excretion of azilsartan, candesartan, carboxylosartan, and valsartan, as well as olmesartan. In contrast, OAT4-mediated uptake of losartan, a monoanionic ARB, was little affected by extracellular Cl - , suggesting that only OAT4-mediated dianion transport is Cl - -sensitive., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2020 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.)

Objective: An application of a specific analysis on recordings obtained from urinary bladder (UB) preparations influenced with Angiotensin II (AngII) and AngII receptor (ATR) blockers was performed., Methods: UB preparations were divided as follows: group 1 stimulated with AngII only; group 2:PD123319 (ATR type-2 blocker)+AngII; group 3:Losartan (ATR type-1 blocker)+AngII. The averaged time and force parameters of the contractions were processed by a spline interpolation and graphic images of the different patterns of the contractile activity were obtained., Results: The speed of AngII-induced UB contraction, when PD123319 was administered, was significantly higher than those, registered by the application of AngII alone and Losartan + AngII. The presence of Losartan markedly delayed the speed of the overall AngII-induced contraction., Conclusion: The study indicates the contribution of both ATR subtypes for the development of AngII-induced UB contraction. Our results showed that probably ATR mediate a reciprocal dynamic response to AngII in the bladder.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently defined as the worst pandemic disease. SARS-CoV-2 infects human cells via the binding of its S protein to the receptor angiotensin-converting enzyme (ACE2). The use of ACEIs/ARBs (RAAS inhibitors) regulates the renin-angiotensin-aldosterone system (RAAS) and may increase ACE2 expression. Considering the large use of ACEIs/ARBs in hypertensive patients, some professional groups are concerned about whether the use of RAAS inhibitors affects the risk of SARS-CoV-2 infection or the risk of severe illness and mortality in COVID-19 patients. In this review, we summarize preclinical and clinical studies to investigate whether the use of ACEIs/ARBs increases ACE2 expression in animals or patients. We also analyzed whether the use of these drugs affects the risk of SARS-CoV-2 infection, severe illness or mortality based on recent studies. Finally, the review suggests that current evidence does not support the concerns., Competing Interests: Declaration of competing interest The authors declare no conflict of interest in relation to this manuscript., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Obesity is a significant breast cancer (BC) risk factor and is associated with 20-40% increased risk in obese post-menopausal women compared to their lean counterparts. Several obesity-related metabolic dysregulations have been linked to BC risk, including overactivation of the renin-angiotensin system (RAS). Currently, RAS inhibitors including angiotensin converting enzyme inhibitor (ACEi) and AT1 receptor blockers (ARBs), are used as safe and effective anti-hypertensive therapies in BC patients. However, it is uncertain how inhibition of RAS in adipose tissue impacts obesity-BC crosstalk. We hypothesized that adipose RAS inhibition will reduce BC cell motility and inflammation. We determined (1) the direct effects of Ang II, ACEi (captopril; Cap) or ARB (telmisartan; Tel) on receptor positive MCF-7 and receptor triple negative MDA-MB-231 cells; and (2) the effects of conditioned media (CM) from human mesenchymal stem cells differentiated into adipocytes, which were pretreated with RAS inhibitors, on BC cells. We demonstrated that direct treatments of BC cells with Ang II, Cap or Tel did not alter inflammatory cytokines in either BC cell line. However, CM from Ang II-pretreated adipocytes significantly increased secretion of pro-inflammatory markers at protein level. RAS inhibitors reduced their secretion in MDA-MB-231, but not in MCF-7 cells. Additionally, CM from adipocytes treated with RAS inhibitors significantly reduced markers of inflammation, fat synthesis, and angiogenesis in both BC cell lines. Furthermore, CM from ACEi pretreated adipocytes reduced cell motility in both BC cell lines. Findings from our study indicate an important role of adipose RAS inhibition in adipocyte and BC cell crosstalk., (Copyright © 2020. Published by Elsevier Inc.)

Coronavirus disease 2019 (COVID-19) is a global pandemic affecting the world, seen in more than 1,300,000 patients. COVID-19 acts through the angiotensin-converting enzyme 2 (ACE2) receptor. Cardiovascular comorbidities are more common with COVID-19, and nearly 10% of cases develop myocarditis (22% of critical patients). Further research is needed to continue or discontinue ACE inhibitors and angiotensin receptor blockers, which are essential in hypertension and heart failure in COVID-19. Intensive research is promising for the treatment and prevention of COVID-19.

Background: Synergistic interactions between neprilysin inhibition (NEPi) with sacubitril and angiotensin receptor type1 blockade (ARB) with valsartan have been implicated in improvement of left ventricular (LV) contractility, relaxation, exercise tolerance, and fibrosis in preexisting heart failure (HF) induced by aortic valve insufficiency (AVI). It is not known whether this pharmacologic synergy can prevent cardiovascular pathology in a similar AVI model. Our aim was to investigate the pharmacology of sacubitril/valsartan in an experimental setting with therapy beginning immediately after creation of AVI., Methods: HF was induced through partial disruption of the aortic valve in rats. Therapy began 3 hours after valve disruption and lasted 8 weeks. Sacubitril/valsartan (68 mg/kg), valsartan (31 mg/kg), sacubitril (31 mg/kg), or vehicle were administered daily via oral gavage (N=8 in each group). Hemodynamic assessments were conducted using Millar technology, and an exercise tolerance test was conducted using a rodent treadmill., Results: Only sacubitril/valsartan increased total arterial compliance and ejection fraction (EF). Therapies with sacubitril/valsartan and valsartan similarly improved load-dependent (dP/dt max ) and load independent indices (Ees) of LV contractility, and exercise tolerance, whereas sacubitril did not. None of the therapies improved LV relaxation (dP/dt min ), whereas all reduced myocardial fibrosis., Conclusions: 1) The synergistic interaction between NEPi and ARB in early therapy with sacubitril/valsartan leads to increased total arterial compliance and EF. 2) Improvement in indices of LV contractility, and exercise tolerance with sacubitril/valsartan is likely because of ARB effect of valsartan. 3) All three therapies provided antifibrotic effects, suggesting both ARB and NEPi are capable of reducing myocardial fibrosis., (Copyright © 2019 Elsevier Inc. All rights reserved.)

"Biased" G protein-coupled receptor (GPCR) agonists preferentially activate pathways mediated by G proteins or β-arrestins. Here, we use double electron-electron resonance spectroscopy to probe the changes that ligands induce in the conformational distribution of the angiotensin II type I receptor. Monitoring distances between 10 pairs of nitroxide labels distributed across the intracellular regions enabled mapping of four underlying sets of conformations. Ligands from different functional classes have distinct, characteristic effects on the conformational heterogeneity of the receptor. Compared to angiotensin II, the endogenous agonist, agonists with enhanced Gq coupling more strongly stabilize an "open" conformation with an accessible transducer-binding site. β-arrestin-biased agonists deficient in Gq coupling do not stabilize this open conformation but instead favor two more occluded conformations. These data suggest a structural mechanism for biased ligand action at the angiotensin receptor that can be exploited to rationally design GPCR-targeting drugs with greater specificity of action., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Introduction: Chronobiology studies the phenomenon of rhythmicity in living organisms. The circadian rhythms are genetically determined and regulated by external synchronizers (the daylight cycle). Several biological processes involved in the pharmacokinetics and pharmacodynamics of drugs are subjected to circadian variations. Chronopharmacology studies how biological rhythms influence pharmacokinetics, pharmacodynamics, and toxicity, and determines whether time-of-day administration modifies the pharmacological characteristics of the drug. Chronotherapy applies chronopharmacological studies to clinical treatments, determining the best biological time for dosing: when the beneficial effects are maximal and the incidence and/or intensity of related side effects and toxicity are minimal. Most water-soluble drugs or drug metabolites are eliminated by urine through the kidney. The rate of drug clearance in the urine depends on several intrinsic variables related to renal function including renal blood flow, glomerular filtration rate, the ability of the kidney to reabsorb or to secrete drugs, urine flow, and urine pH, which influences the degree of urine acidification. Curiously, all these variables present a circadian behavior in different mammalian models., Conclusion: The circadian rhythms have influence in the renal physiology, pathophysiology, and pharmacology, and these data should be taken into account in clinical nephrology practice.

Fimasartan (FMS), an angiotensin II receptor antagonist, is metabolized to FMS S-oxide, FMS N-glucuronide, oxidative desulfurized FMS (BR-A-557), and hydroxy-n-butyl FMSs. The purpose of this study was to characterize enzymes involved in NADPH-dependent FMS metabolism using recombinant enzymes such as cytochrome P450 (CYP) and flavin-containing monooxygenase (FMO), as well as selective chemical inhibitors. The results showed that CYP, but not FMO, plays a major role in FMS metabolism. CYP2C9, CYP3A4, and CYP3A5 were involved in the formation of FMS S-oxide, which was further metabolized to BR-A-557 by CYP3A4/5. CYP2C9 played an exclusive role in n-butyl hydroxylation. The specificity constant (kcat/Km) values for S-oxidation by CYP2C9, CYP3A4, and CYP3A5 were 0.21, 0.34, and 0.19 μM-1∙min-1, respectively. The kcat/Km values of hydroxylation at the 1-, 2-/3-, and 4-n-butyl group in CYP2C9 were 0.0076, 0.041, and 0.035 μM-1∙min-1, respectively. The kcat and Km values provide information for the prediction of FMS metabolism in vivo. In addition, simultaneous determination of the FMS metabolites may be used to evaluate CYP2C9 and CYP3A4/5 activity., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Animal studies have reported on the benefits of ARB on bone mass. However, the underlying mechanism for angiotensin II (AngII)/AngII receptor blockade (ARB) in regulating bone mass remains elusive. Since high levels of plasma and urine cAMP are observed in osteoporotic and hypertensive patients, we hypothesized that cAMP may be an important molecule for the downstream events of the activation of AT receptors, members of the G-protein-coupled receptor family, in regulating bone turnover. In this study, micro-CT and X-ray analyses indicated that AngII decreased bone mass via biasing bone resorption over bone formation in osteoporotic mice. However, these adverse effects were blocked by olmesartan and PD123319. In vitro, AngII was shown to downregulate osteogenic differentiation and matrix mineralization, but to upregulate osteoclastic activity by mainly affecting osteoblasts producing osteoclastogenesis-associated key soluble factors, including M-CSF and RANKL. Similarly, ARB treatment exhibited antagonistic effects on AngII. In conclusion, osteoblasts are the directly targeted cells. ARB1 exhibits a greater capacity to increase bone mass than ARB2. The cAMP-dependent PKA pathway plays an important role in AngII/ARB on changing bone mass., (© 2017 S. Karger AG, Basel.)

Sacubitril was recently approved by the Food and Drug Administration for use in combination with valsartan for the treatment of patients with heart failure with reduced ejection fraction. As a prodrug, sacubitril must be metabolized (hydrolyzed) to its active metabolite sacubitrilat (LBQ657) to exert its intended therapeutic effects. Thus, understanding the determinants of sacubitril activation will lead to the improvement of sacubitril pharmacotherapy. The objective of this study was to identify the enzyme(s) responsible for the activation of sacubitril, and determine the impact of genetic variation on sacubitril activation. First, an incubation study of sacubitril with human plasma and the S9 fractions of human liver, intestine, and kidney was conducted. Sacubitril was found to be activated by human liver S9 fractions only. Moreover, sacubitril activation was significantly inhibited by the carboxylesterase 1 (CES1) inhibitor bis-(p-nitrophenyl) phosphate in human liver S9. Further incubation studies with recombinant human CES1 and carboxylesterase 2 confirmed that sacubitril is a selective CES1 substrate. The in vitro study of cell lines transfected with wild-type CES1 and the CES1 variant G143E (rs71647871) demonstrated that G143E is a loss-of-function variant for sacubitril activation. Importantly, sacubitril activation was significantly impaired in human livers carrying the G143E variant. In conclusion, sacubitril is selectively activated by CES1 in human liver. The CES1 genetic variant G143E can significantly impair sacubitril activation. Therefore, CES1 genetic variants appear to be an important contributing factor to interindividual variability in sacubitril activation, and have the potential to serve as biomarkers to optimize sacubitril pharmacotherapy., (Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.)

1. Fimasartan is an angiotensin receptor II antagonist used to treat patients with hypertension. This drug is mainly excreted into bile as either the parent compound or a glucuronide conjugate. In this study, we examined the glucuronidation of fimasartan and characterized the UDP-glucuronosyltransferases (UGTs) responsible for the glucuronidation. 2. Only one type of fimasartan glucuronide was observed after incubation with pooled human liver microsomes (HLMs) and was identified as an N2-glucuronide based on comparison with an authentic standard. 3. Among the 12 UGT isoforms tested, UGT1A1, UGT1A3 and UGT2B7 showed catalytic activity toward fimasartan glucuronidation. The intrinsic clearance (CLint) of UGT1A3 was 68.5- and 21.4-fold higher than that of UGT1A1 and UGT2B7, respectively, and the estimated relative contribution of UGT1A3 in human liver was 94.1%. Both chemical inhibition and correlation studies demonstrated that fimasartan glucuronidation activity in HLMs was significantly related with UGT1A3 activity. Fimasartan glucuronide was identified as a substrate for P-glycoprotein (Pgp) and breast cancer response protein (BCRP). 4. These findings collectively indicate that UGT1A3 is the major UGT isoform responsible for the glucuronidation of fimasartan, and this glucuronide is excreted from hepatocytes via MDR1 and BCRP.

Arachidonic acid (AA) is metabolized to epoxyeicosatrienoic acids (EETs) via cytochrome enzymes such as CYP 2C9, 2C8 and 2J2. EETs play a role in cardioprotection and regulation of blood pressure. Recently, adverse reactions such as sudden heart attack and fatal myocardial infarction were reported among patients taking angiotensin II receptor blockers (ARBs). As some ARBs have affinity for these CYP enzymes, metabolic inhibition of AA by ARBs is a possible cause for the increase in cardiovascular events. In this study, we quantitatively investigated the inhibitory effects of ARBs on the formation of EETs and further metabolites, dihydroxyeicosatrienoic acids (DHETs), from AA via CYP2C8. In incubations with recombinant CYP2C8 in vitro, the inhibitory effects were compared by measuring EETs and DHETs by HPLC-MS/MS. Inhibition of AA metabolism by ARBs was detected in a concentration-dependent manner with IC50 values of losartan (42.7 µM), telmisartan (49.5 µM), irbesartan (55.6 µM), olmesartan (66.2 µM), candesartan (108 µM), and valsartan (279 µM). Losartan, telmisartan and irbesartan, which reportedly accumulate in the liver and kidneys, have stronger inhibitory effects than other ARBs. The lower concentration of EETs leads to less protective action on the cardiovascular system and a higher incidence of adverse effects such as sudden heart attack and myocardial infarction in patients taking ARBs.

While the molecular structures of angiotensin II (Ang II) type 1 (AT1) receptor blockers (ARBs) are very similar, they are also slightly different. Although each ARB has been shown to exhibit a unique mode of binding to AT1 receptor, different positions of the AT1 receptor have been analyzed and computational modeling has been performed using different crystal structures for the receptor as a template and different kinds of software. Therefore, we systematically analyzed the critical positions of the AT1 receptor, Tyr(113), Tyr(184), Lys(199), His(256) and Gln(257) using a mutagenesis study, and subsequently performed computational modeling of the binding of ARBs to AT1 receptor using CXCR4 receptor as a new template and a single version of software. The interactions between Tyr(113) in the AT1 receptor and the hydroxyl group of olmesartan, between Lys(199) and carboxyl or tetrazole groups, and between His(256) or Gln(257) and the tetrazole group were studied. The common structure, a tetrazole group, of most ARBs similarly bind to Lys(199), His(256) and Gln(257) of AT1 receptor. Lys(199) in the AT1 receptor binds to the carboxyl group of EXP3174, candesartan and azilsartan, whereas oxygen in the amidecarbonyl group of valsartan may bind to Lys(199). The benzimidazole portion of telmisartan may bind to a lipophilic pocket that includes Tyr(113). On the other hand, the n-butyl group of irbesartan may bind to Tyr(113). In conclusion, we confirmed that the slightly different structures of ARBs may be critical for binding to AT1 receptor and for the formation of unique modes of binding.

Olmesartan medoxomil (OM) is a prodrug-type angiotensin II type 1 receptor blocker (ARB). We recently identified carboxymethylenebutenolidase homolog (CMBL) as the responsible enzyme for OM bioactivation in humans. In the present study, we compared the bioactivating properties of OM with those of other prodrug-type ARBs, candesartan cilexetil (CC) and azilsartan medoxomil (AM), by focusing on interspecies differences and tissue specificity. In in-vitro experiments with pooled tissue subcellular fractions of mice, rats, monkeys, dogs, and humans, substantial OM-hydrolase activities were observed in cytosols of the liver, intestine, and kidney in all the species tested except for dog intestine, which showed negligible activity, whereas lung cytosols showed relatively low activities compared with the other tissues. AM-hydrolase activities were well correlated with the OM-hydrolase activities. In contrast, liver microsomes exhibited the highest CC-hydrolase activity among various tissue subcellular fractions in all the species tested. As a result of Western blot analysis with the tissue subcellular fractions, the band intensities stained with anti-human CMBL and carboxylesterase 1 (CES1) antibodies well reflected OM- and AM-hydrolase activities and CC-hydrolase activity, respectively, in animals and humans. Recombinant human CMBL and CES1 showed significant AM- and CC-hydrolase activities, respectively, whereas CC hydrolysis was hardly catalyzed with recombinant carboxylesterase 2 (CES2). In conclusion, OM is bioactivated mainly via intestinal and additionally hepatic CMBL not only in humans but also in mice, rats, and monkeys, while CC is bioactivated via hepatic CES1 rather than intestinal enzymes, including CES2. AM is a substrate for CMBL.

High levels of the novel inflammatory marker YKL-40 have been demonstrated in inflammatory environments and in remodeling of the extracellular matrix. Both are key components in atrial wall remodeling in atrial fibrillation (AF). We studied the relation between rhythm outcome after electrical cardioversion (ECV) for persistent AF and serum levels of YKL-40. A secondary point of interest was a potential effect of the angiotensin receptor blocker candesartan on YKL-40 levels. In the Candesartan in the Prevention of Relapsing Atrial Fibrillation (CAPRAF) study, 171 patients with persistent AF were randomized to receive candesartan 8mg once daily or placebo for 3-6 weeks before ECV and candesartan 16mg once daily or placebo for 6 months after ECV. Serum levels of YKL-40 were measured in fasting blood samples collected at baseline and at end of the study. Mean age was 64±11 years, and 39 (22.8%) were women. Sinus rhythm was maintained for 6 months after ECV in 41 (23.9%). Baseline levels of YKL-40 were significantly correlated to age (Spearmans rho; rs=0.442; p<0.001), CHA2DS2-VASc(1) score (rs=0.256; p<0.001) and left atrial diameter (rs=0.185; p=0.017). By use of Kaplan-Meier quartile analysis of baseline YKL-40 levels, no relation between YKL-40 levels and risk of AF recurrence was found. End of study YKL-40 levels were unchanged from baseline, both in patients with AF recurrence and those maintaining sinus rhythm for 6 months. Treatment with candesartan had no influence on serum YKL-40 levels., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Glucuronidation of telmisartan comprises nearly its entire metabolic clearance in several mammalian species including human. However, data were lacking for the cat, a species noted for its inability to glucuronidate some drugs. Therefore, the glucuronidation of telmisartan was investigated using feline liver microsomes and compared to liver microsomes of rats, dogs, and human, intestinal human microsomes and cell lines expressing human UDP-glucuronosyltransferases (UGT). Incubation of telmisartan with cat liver microsomes readily yielded telmisartan glucuronide, and pooled (N = 3 for each gender) cat liver microsomes even showed the highest glucuronidation rate (cat > dog >> human > rat). Michaelis Menten kinetics were observed with Km of 7.5 and 10 μm and Vmax of 3.9 and 3.3 nmol/min/mg for male and female cats, respectively. Confirming the in vitro data, telmisartan glucuronide was detected as the major circulating metabolite in cat plasma. To elucidate which UGT enzymes are involved, telmisartan was incubated with cell lines expressing human UGTs. The highest glucuronidation activity was observed for UGT1A8, UGT1A7, and UGT1A9. In conclusion, telmisartan was effectively glucuronidated in cats. Defects of the UGT1A6 gene in cats do not affect the glucuronidation of telmisartan as it is not a substrate of human UGT1A6., (© 2012 Blackwell Publishing Ltd.)

To clarify the hypotensive mechanism of angiotensin II receptor-blockers (ARBs), drug concentrations in plasma and vascular tissues were measured using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and imaging mass spectrometry. In spontaneously hypertensive rats, systolic blood pressure (SBP) was measured 2 and 24 h after administration of candesartan cilexetil (0.3, 1, or 3 mg/kg) or azilsartan (0.3, 1, or 3 mg/kg). SBP was similarly lowered 2 h after administration of azilsartan or candesartan cilexetil, but it was significantly lower in the azilsartan-treated group than in the candesartan cilexetil-treated group at 24 h. Angiotensin II-induced vascular contractions were similarly attenuated 2 h after administration of these drugs, and the contractions were significantly lower in the azilsartan-treated group at 24 h. Although plasma concentration was significantly lower in the azilsartan-treated group at 24 h, vascular concentration of azilsartan was significantly greater than that of candesartan. Significant correlations between SBP and vascular concentrations were observed both at 2 and 24 h, while no significant correlation was observed between plasma and vascular concentrations. In conclusion, the mechanism of ARB-induced hypotension is likely to depend on vascular concentrations rather than plasma concentrations.

It has been reported that in vivo biliary clearance can be predicted using sandwich-cultured rat and human hepatocytes. The predicted apparent biliary clearance (CL(bile, app)) from sandwich- cultured rat hepatocytes (SCRH) based on medium concentrations correlates to in vivo CL(bile, app) based on plasma concentrations of angiotensin II receptor blockers (ARBs), HMG-CoA reductase inhibitors (statins), β-lactam antibiotics, and topotecan. However, the predicted biliary clearance from SCRH was 7- to 300-fold lower than in vivo biliary clearance. We speculated that the process of biliary excretion might not have been evaluated using sandwich-cultured hepatocytes. To evaluate this issue, intrinsic biliary clearance (CL(bile, int)) based on intracellular compound concentrations was evaluated to investigate the in vitro-in vivo correlation of this process among ARBs, statins, β-lactam antibiotics, and topotecan. Intrinsic biliary clearance in SCRH correlated to in vivo values obtained by constant intravenous infusion of six compounds, but not rosuvastatin and cefmetazole, to rats. Moreover, differences between SCRH and in vivo CL(bile, int) (0.7-6-fold) were much smaller than those of CL(bile, app) (7-300-fold). Therefore, in vivo CL(bile, int) is more accurately reflected using SCRH than CL(bile, app). In conclusion, to predict in vivo biliary clearance more accurately, CL(bile, int) should be evaluated instead of CL(bile, app) between SCRH and in vivo.

The density of Angiotensin II (Ang) receptors on tissue surfaces is regulated by multiple hormones, cytokines and metabolic factors and is profoundly affected by various pathological conditions, such as age, diet and environmental conditions. The participation of several cardiovascular risk factors in the regulation of Angiotensin II receptor expression has been incompletely studied. We performed an ex-vivo study with human aortic postsurgical specimens to test the hypothesis that Ang AT1 and AT2 receptor expression in human aortic arteries is associated with the presence of cardiovascular risk factors. We included 31 Mexican patients with coronary artery disease. We evaluated Angiotensin II receptor expression by immunostaining and angiotensin converting enzyme insertion/deletion (ACE I/D) polymorphisms by polymerase chain reaction. AT1 and AT2 receptor expression was increased in the aortic segments from the cardiovascular patients compared with control arteries and in patients with the DD genotype. There was a correlation between increased AT1 receptor expression and the number of cardiovascular risk factors present in the patient. Furthermore, reduction of AT1 expression correlated with the number of drug combinations used in the patients. These correlations were not present with respect to AT2 receptor expression. We suggest that increased AT1 receptor expression is associated with the DD genotype. Thus the presence of several cardiovascular risk factors as well as DD genotype, induce AT1 expression increasing the probability to develop coronary occlusive disease., (Copyright © 2011 Elsevier Inc. All rights reserved.)