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This study evaluates the microencapsulation of peanut skin phenolic compounds by spray drying, assessing their physicochemical properties and storage stability and the protective effect against oxidative deterioration in walnut kernels. Extraction yield, total phenolic content, and HPLC-ESI-MS/MS analysis were performed on peanut skin crude extract (PCE). Microencapsulation of PCE with 10%, 20%, and 30% maltodextrin via spray drying was conducted. The drying yield, phenolic encapsulation efficiency, moisture content, morphology, particle size, and stability during dry storage (23°C) and in water (23 and 100°C) were assessed for the microcapsules. PCE contained 950.29 mg GAE/g of total polyphenolic compounds, primarily hydroxycinnamic acid-derived phenolic acids and procyanidins. Microcapsules with 20% maltodextrin exhibited the best properties (drying yield, encapsulation efficiency, and stability). These microcapsules were incorporated into an edible chickpea-based coating, which was applied to walnuts and stored at 40°C for 15 days. Peroxide value, conjugated dienes, volatile compounds, and fatty acid profile were analyzed on samples from storage. The chickpea-based coating combined with PCE microcapsules effectively preserves walnut quality during storage, offering a viable and natural alternative to synthetic antioxidants such as BHT, addressing current concerns in food preservation. PRACTICAL APPLICATION: Peanut skins are a byproduct of the peanut industry with low commercial value. These skins are rich in polyphenols, which exhibit potent antioxidant activity. This study investigates the microencapsulation of polyphenolic peanut extract and its incorporation into a chickpea-based edible coating. The prepared coating demonstrated a remarkable protective effect against lipid oxidation in walnuts, extending their shelf life. These findings present a sustainable strategy that adds value to agro-industrial residues and aligns with circular economy principles. This innovation offers a natural and effective solution to enhance the stability and quality of lipid-rich foods., (© 2025 Institute of Food Technologists.)

Background: During diabetes, prorenin is highly produced by the renal collecting ducts. The binding of prorenin to (pro)renin receptor (PRR) on the apical plasma membrane triggers intracellular profibrotic genes, including TGF-β and CTGF. However, the underlying mechanisms contributing to the stimulation of these pathways remain unclear. Hence, we hypothesize that the glucose transporter-1 (GLUT1) favors the PRR-dependent stimulation of TGF-β and CTGF in the distal nephron segments during high glucose (HG) conditions., Methods: To test this hypothesis, primary cultured renal inner medullary collecting duct (IMCD) cells were treated with normal glucose (NG, 5 mM) or high glucose (HG, 25 mM) for 48 h in the presence or absence of the GLUT1-specific inhibitor BAY 876 (2 nM). Additionally, IMCD cells were treated with the PRR antagonist PRO20. The expression of TGF-β and CTGF was quantified by immunoblot and qRT-PCR., Results: HG increased GLUT1 mRNA and protein abundance, while BAY 876 inhibited these responses. HG treatment upregulated PRR, but the concomitant treatment with BAY 876 partially prevented this effect. TGF-β and CTGF expressions were augmented in IMCD cells treated with HG. However, PRO20 prevented the increases in TGF-β but not those of CTGF. GLUT1 inhibition partially prevented the increases in reactive oxygen species (ROS) during HG while PRO20 did not. ROS scavenging impaired CTGF upregulation during HG conditions. Additionally, long-term exposure to HG increases lipid peroxidation and reduced cell viability., Conclusions: The data indicate that glucose transportation via GLUT1 is implicated in the PRR-dependent upregulation of TGF-β while CTGF is mediated mainly via a mechanism depending on ROS formation in renal medullary collecting duct cells., (© 2024. The Author(s).)

Background: The Cosmos sulphureus Cav. plant is studied for its high polyphenolic content with antioxidant properties. Its flowers, rich in phenolic acids, flavonoids, and tannins, hold promise as antioxidants in food preservation. The inclusion of these compounds in chickpea-based coatings with a previously studied preservative effect would be an excellent option as a food preservation method and microencapsulation addresses challenges like dispersion and degradation of polyphenols in the coating. The objective of this research was to evaluate the in vitro antioxidant activity of Cosmos sulphureus leaves, seed, and flower extracts and explore the protective effects of chickpea-based coatings containing microcapsules of flower polyphenolic extract on the chemical quality of stored roasted sunflower seeds during storage., Results: The ethanolic leaf extract exhibited the highest antiradical activity, followed by the aqueous flower extract. After a storage period of 15 days, at 40 °C, the chickpea-based coatings effectively delayed lipid oxidation in the roasted sunflowers seeds, and the inclusion of polyphenolic microcapsules with 0.01% extract (SMC 0.01%) in the coating significantly improved the protective effect. By day 15 of storage, SMC 0.01% showed comparable peroxide value, conjugated dienes, and linoleic acid content to samples containing the synthetic antioxidant BHT (butylated hydroxytoluene). Samples that only contained chickpea-based coating and coating with polyphenolic microcapsules with 0.005% extract exhibited significantly greater reduction in fatty acid content compared to the 0.01% SMC treatment., Conclusion: The chickpea-based coating with polyphenolic microcapsules demonstrated antioxidant activity akin to synthetic BHT, offering a promising biopackaging solution for lipid-rich foods like roasted sunflower seeds. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

The two-kidney, one-clip (2K1C) Goldblatt rodent model elicits a reduction in renal blood flow (RBF) in the clipped kidney (CK). The reduced RBF and oxygen bio-ability causes the accumulation of the tricarboxylic cycle intermediary, α-ketoglutarate, which activates the oxoglutarate receptor-1 (OXGR1). In the kidney, OXGR1 is abundantly expressed in intercalated cells (ICs) of the collecting duct (CD), thus contributing to sodium transport and electrolyte balance. The (pro)renin receptor (PRR), a member of the renin-angiotensin system (RAS), is a key regulator of sodium reabsorption and blood pressure (BP) that is expressed in ICs. The PRR is upregulated in 2K1C rats. Here, we tested the hypothesis that chronic reduction in RBF in the CK leads to OXGR1-dependent PRR upregulation in the CD and alters sodium balance and BP in 2K1C mice. To determine the role of OXGR1 in regulating the PRR in the CDs during renovascular hypertension, we performed 2K1C Goldblatt surgery (clip = 0.13 mm internal gap, 14 days) in two groups of male mice: (1) mice treated with Montelukast (OXGR1 antagonist; 5 mg/Kg/day); (2) OXGR1 -/- knockout mice. Wild-type and sham-operated mice were used as controls. After 14 days, 2K1C mice showed increased systolic BP (SBP) (108 ± 11 vs. control 82 ± 5 mmHg, p < 0.01) and a lower natriuretic response after the saline challenge test. The CK group showed upregulation of erythropoietin, augmented α-ketoglutarate, and increased PRR expression in the renal medulla. The CK of OXGR1 knockout mice and mice subjected to the OXGR1 antagonist elicited impaired PRR upregulation, attenuated SBP, and better natriuretic responses. In 2K1C mice, the effect of reduced RBF on the OXGR1-dependent PRR upregulation in the CK may contribute to the anti-natriuretic and increased SBP responses.

Background: High salt (HS) intake induces an augmented hypertensive response to nitric oxide (NO) inhibition, though it causes minimal changes in blood pressure (BP) in NO intact condition. The cause of such augmentation is not known. HS induces tumor necrosis factor-alpha (TNFα) production that causes natriuresis via activation of its receptor type 1 (TNFR1). We hypothesized that NO deficiency reduces renal TNFR1 activity, leading to enhanced sodium retention and hypertension., Methods: We examined the changes in renal TNFR1 protein expression (Immunohistochemistry analyses) after HS (4% NaCl) intake in wild-type mice (WT, C57BL6) treated with a NO synthase (NOS) inhibitor, nitro-l-arginine methyl ester (L-NAME; 0.05 mg/min/g; osmotic mini-pump), as well as in endothelial NOS knockout mice (eNOSKO) and compared the responses in WT mice with normal salt (NS; 0.3% NaCl) intake. BP was measured with tail-cuff plethysmography and 24-hour urine collections were made using metabolic cages., Results: HS alone did not alter mean BP in untreated mice (76 ± 3 to 77 ± 1 mm Hg) but induced an augmented response in L-NAME treated (106 ± 1 vs. 97 ± 2 mm Hg) and in eNOSKO (107 ± 2 vs. 89 ± 3 mm Hg) mice. The percentage area of TNFR1 expression in renal tissue was higher in WT + HS (4.1 + 0.5%) than in WT + NS mice (2.7 ± 0.6%). However, TNFR1 expression was significantly lower in L-NAME treated WT + NS (0.9 ± 0.1%) and in eNOSKO + NS (1.4 ± 0.2%) than in both WT + NS and WT + HS mice., Conclusions: These data indicate that TNFR1 activity is downregulated in NO deficient conditions, which facilitates salt retention leading to augmented hypertension during HS intake., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Journal of Hypertension, Ltd.)

Renin was discovered more than a century ago. Since then, the functions of the renin-angiotensin system in the kidney have been the focus of intensive research revealing its importance in regulation of renal physiology and in the pathogenesis of heart, vascular, and kidney diseases. Inhibitors of renin-angiotensin system components are now foundational therapies for a range of kidney and cardiovascular diseases from hypertension to heart failure to diabetic nephropathy. Despite years of voluminous research, emerging studies continue to reveal new complexities of the regulation of the renin-angiotensin system within the kidney and identification of nonclassical components of the system like the prorenin receptor (PRR) and ACE2 (angiotensin-converting enzyme 2), with powerful renal effects that ultimately impact the broader cardiovascular system. With the emergence of a range of novel therapies for cardiovascular and kidney diseases, the importance of a detailed understanding of the renin-angiotensin system in the kidney will allow for the development of informed complementary approaches for combinations of treatments that will optimally promote health and longevity over the century ahead., Competing Interests: None.

Increased body weight (BW) induces inappropriate renin-angiotensin system (RAS) activation. The activation of the intrarenal RAS is associated with increased urinary angiotensinogen (uAGT), blood pressure (BP), and kidney damage. Here, we examined uAGT excretion levels in young non-diabetic human subjects with overweight (OW) and non-diabetic mice with high-fat diet (HFD)-induced OW. Human subjects (women and men; 20-28 years old) included two groups: (a) overweight (OW, n = 17, BMI ≥ 25); and (b) controls (normal weight (NW; n = 26, BMI ≤ 25). In these subjects, we measured BP, albuminuria, and protein levels of uAGT by ELISA adjusted by urinary creatinine (expressed by uAGT/uCrea). Mice (female and male C57BL/6J mice, 8 ± 2 weeks of age) also included two groups: HFD or normal fat diet (NFD) fed for 8 weeks. We measured BW, fasting blood glucose (FBG), BP by telemetry, albuminuria, and uAGT by ELISA. In humans: (i) no significant changes were observed in BP, albuminuria, and FBG when comparing NW and OW subjects; (ii) multivariate logistic regression analysis of independent predictors related to uAGT/uCrea levels demonstrated a strong association between uAGT and overweight; (iii) urinary reactive oxygen species (ROS) were augmented in men and women with OW; (iv) the uAGT/uCrea ratio was higher in men with OW. However, the uAGT/uCrea values were lower in women even with OW. In mice: (i) males fed an HFD for 8 weeks became OW while females did not; (ii) no changes were observed either in FBG, BP, or albuminuria; (iii) kidney ROS were augmented in OW male mice after 28 weeks but not in females; (iv) OW male mice showed augmented excretion of uAGT but this was undetectable in females fed either NFD or HFD. In humans and mice who are OW, the urinary excretion of AGT differs between males and females and overcomes overt albuminuria.

Plasma soluble prorenin receptor (sPRR) displays sexual dimorphism and is higher in women with type 2 diabetes mellitus (T2DM). However, the contribution of plasma sPRR to the development of vascular complications in T2DM remains unclear. We investigated if plasma sPRR contributes to sex differences in the activation of the systemic renin-angiotensin-aldosterone system (RAAS) and vascular damage in a model of high-fat diet (HFD)-induced T2DM. Male and female C57BL/6J mice were fed either a normal fat diet (NFD) or an HFD for 28 wk to assess changes in blood pressure, cardiometabolic phenotype, plasma prorenin/renin, sPRR, and ANG II. After completing dietary protocols, tissues were collected from males to assess vascular reactivity and aortic reactive oxygen species (ROS). A cohort of male mice was used to determine the direct contribution of increased systemic sPRR by infusion. To investigate the role of ovarian hormones, ovariectomy (OVX) was performed at 32 wk in females fed either an NFD or HFD. Significant sex differences were found after 28 wk of HFD, where only males developed T2DM and increased plasma prorenin/renin, sPRR, and ANG II. T2DM in males was accompanied by nondipping hypertension, carotid artery stiffening, and aortic ROS. sPRR infusion in males induced vascular thickening instead of material stiffening caused by HFD-induced T2DM. While intact females were less prone to T2DM, OVX increased plasma prorenin/renin, sPRR, and systolic blood pressure. These data suggest that sPRR is a novel indicator of systemic RAAS activation and reflects the onset of vascular complications during T2DM regulated by sex. NEW & NOTEWORTHY High-fat diet (HFD) for 28 wk leads to type 2 diabetes mellitus (T2DM) phenotype, concomitant with increased plasma soluble prorenin receptor (sPRR), nondipping blood pressure, and vascular stiffness in male mice. HFD-fed female mice exhibiting a preserved cardiometabolic phenotype until ovariectomy revealed increased plasma sPRR and blood pressure. Plasma sPRR may indicate the status of systemic renin-angiotensin-aldosterone system (RAAS) activation and the onset of vascular complications during T2DM in a sex-dependent manner.

The Na + -activated Na + channel (Nax) and salt-inducible kinase (SIK) are stimulated by increases in local Na + concentration, affecting (Na + + K + )-ATPase activity. To test the hypothesis that the triad Nax/SIK/(Na + + K + )-ATPase contributes to kidney injury and salt-sensitive hypertension (HTN), uninephrectomized male Wistar rats (200 g; n = 20) were randomly divided into 4 groups based on a salt diet (normal salt diet; NSD-0.5% NaCl-or high-salt diet; HSD-4% NaCl) and subcutaneous administration of saline (0.9% NaCl) or deoxycorticosterone acetate (DOCA, 8 mg/kg), as follows: Control (CTRL), CTRL-Salt, DOCA, and DOCA-Salt, respectively. After 28 days, the following were measured: kidney function, blood pressure, (Na + + K + )-ATPase and SIK1 kidney activities, and Nax and SIK1 renal expression levels. SIK isoforms in kidneys of CTRL rats were present in the glomerulus and tubular epithelia; they were not altered by HSD and/or HTN. CTRL-Salt rats remained normotensive but presented slight kidney function decay. HSD rats displayed augmentation of the Nax/SIK/(Na + + K + )-ATPase pathway. HTN, kidney injury, and kidney function decay were present in all DOCA rats; these were aggravated by HSD. DOCA rats presented unaltered (Na + + K + )-ATPase activity, diminished total SIK activity, and augmented SIK1 and Nax content in the kidney cortex. DOCA-Salt rats expressed SIK1 activity and downregulation in (Na + + K + )-ATPase activity in the kidney cortex despite augmented Nax content. The data of this study indicate that the (Na + + K + )-ATPase activity response to SIK is attenuated in rats under HSD, independent of HTN, as a mechanism contributing to kidney injury and salt-sensitive HTN.

Increases of soluble urokinase plasminogen activator receptor (suPAR) were measured in both urine and plasma of a Chlorocebus aethiops (African green monkey; AGM) mucosal infected with SARS-CoV-2. The data indicate that elevated suPAR may be associated with renal dysfunction and pathology in the context of COVID-19., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The (Pro)renin receptor ([P]RR), also known as ATP6AP2, is a single-transmembrane protein that is implicated in a multitude of biological processes. However, the exact role of ATP6AP2 during blood vessel development remains largely undefined. Here, we use an inducible endothelial cell-specific (EC-specific) Atp6ap2-KO mouse model to investigate the role of ATP6AP2 during both physiological and pathological angiogenesis in vivo. We observed that postnatal deletion of Atp6ap2 in ECs results in cell migration defects, loss of tip cell polarity, and subsequent impairment of retinal angiogenesis. In vitro, Atp6ap2-deficient ECs similarly displayed reduced cell migration, impaired sprouting, and defective cell polarity. Transcriptional profiling of ECs isolated from Atp6ap2 mutant mice further indicated regulatory roles in angiogenesis, cell migration, and extracellular matrix composition. Mechanistically, we provided evidence that expression of various extracellular matrix components is controlled by ATP6AP2 via the ERK pathway. Furthermore, Atp6ap2-deficient retinas exhibited reduced revascularization in an oxygen-induced retinopathy model. Collectively, our results demonstrate a critical role of ATP6AP2 as a regulator of developmental and pathological angiogenesis.

The production of renin by the principal cells of the collecting duct has widened our understanding of the regulation of intrarenal angiotensin II (Ang II) generation and blood pressure. In the collecting duct, Ang II increases the synthesis and secretion of renin by mechanisms involving the activation of Ang II type 1 receptor (AT1R) via stimulation of the PKCα, Ca 2+ , and cAMP/PKA/CREB pathways. Additionally, paracrine mediators, including vasopressin (AVP), prostaglandins, bradykinin (BK), and atrial natriuretic peptide (ANP), regulate renin in principal cells. During Ang II-dependent hypertension, despite plasma renin activity suppression, renin and prorenin receptor (RPR) are upregulated in the collecting duct and promote de novo formation of intratubular Ang II. Furthermore, activation of PRR by its natural agonists, prorenin and renin, may contribute to the stimulation of profibrotic factors independent of Ang II. Thus, the interactions of RAS components with paracrine hormones within the collecting duct enable tubular compartmentalization of the RAS to orchestrate complex mechanisms that increase intrarenal Ang II, Na+ reabsorption, and blood pressure., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

[Figure: see text].

In hypertension induced by angiotensin II (AngII) administration with high salt (HS) intake, intrarenal angiotensinogen (AGT) and tumor necrosis factor-alpha (TNF-α) levels increase. However, TNF-α has been shown to suppress AGT formation in cultured renal proximal tubular cells. We examined the hypothesis that elevated AngII levels during HS intake reduces TNF-α receptor type 1 (TNFR1) activity in the kidneys, thus facilitating increased intrarenal AGT formation. The responses to HS diet (4% NaCl) with chronic infusion of AngII (25 ng/min) via implanted minipump for 4 weeks were assessed in wild-type (WT) and knockout (KO) mice lacking TNFR1 or TNFR2 receptors. Blood pressure was measured by tail-cuff plethysmography, and 24-h urine samples were collected using metabolic cages prior to start (0 day) and at the end of 2nd and 4th week periods. The urinary excretion rate of AGT (uAGT; marker for intrarenal AGT) was measured using ELISA. HS +AngII treatment for 4 weeks increased mean arterial pressure (MAP) in all strains of mice. However, the increase in MAP in TNFR1KO (77 ± 2 to 115 ± 3 mmHg; n = 7) was significantly greater (p < 0.01) than in WT (76 ± 1 to 102 ± 2 mmHg; n = 7) or in TNFR2KO (78 ± 2 to 99 ± 5 mmHg; n = 6). The increase in uAGT at 4th week was also greater (p < 0.05) in TNFR1KO mice (6 ± 2 to 167 ± 75 ng/24 h) than that in WT (6 ± 3 to 46 ± 16 ng/24 h) or in TNFR2KO mice (8 ± 7 to 65 ± 44 ng/24 h). The results indicate that TNFR1 exerts a protective role by mitigating intrarenal AGT formation induced by elevated AngII and HS intake., (© 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Growing evidence indicates that prorenin receptor (PRR) is upregulated in collecting duct (CD) of diabetic kidney. Prorenin is secreted by the principal CD cells, and is the natural ligand of the PRR. PRR activation stimulates fibrotic factors, including fibronectin, collagen, and transforming growth factor-β (TGF-β) contributing to tubular fibrosis. However, whether high glucose (HG) contributes to this effect is unknown. We tested the hypothesis that HG increases the abundance of PRR at the plasma membrane of the CD cells, thus contributing to the stimulation of downstream fibrotic factors, including TGF-β, collagen I, and fibronectin. We used streptozotocin (STZ) male Sprague-Dawley rats to induce hyperglycemia for 7 days. At the end of the study, STZ-induced rats showed increased prorenin, renin, and angiotensin (Ang) II in the renal inner medulla and urine, along with augmented downstream fibrotic factors TGF-β, collagen I, and fibronectin. STZ rats showed upregulation of PRR in the renal medulla and preferential distribution of PRR on the apical aspect of the CD cells. Cultured CD M-1 cells treated with HG (25 mM for 1 h) showed increased PRR in plasma membrane fractions compared to cells treated with normal glucose (5 mM). Increased apical PRR was accompanied by upregulation of TGF-β, collagen I, and fibronectin, while PRR knockdown prevented these effects. Fluorescence resonance energy transfer experiments in M-1 cells demonstrated augmented prorenin activity during HG conditions. The data indicate HG stimulates profibrotic factors by inducing PRR translocation to the plasma membrane in CD cells, which in perspective, might be a novel mechanism underlying the development of tubulointerstitial fibrosis in diabetes mellitus.

The intrarenal renin-angiotensin system is critical for the regulation of tubule sodium reabsorption, renal haemodynamics and blood pressure. The excretion of renin in urine can result from its increased filtration, the inhibition of renin reabsorption by megalin in the proximal tubule, or its secretion by the principal cells of the collecting duct. Modest increases in circulating or intrarenal angiotensin II (ANGII) stimulate the synthesis and secretion of angiotensinogen in the proximal tubule, which provides sufficient substrate for collecting duct-derived renin to form angiotensin I (ANGI). In models of ANGII-dependent hypertension, ANGII suppresses plasma renin, suggesting that urinary renin is not likely to be the result of increased filtered load. In the collecting duct, ANGII stimulates the synthesis and secretion of prorenin and renin through the activation of ANGII type 1 receptor (AT1R) expressed primarily by principal cells. The stimulation of collecting duct-derived renin is enhanced by paracrine factors including vasopressin, prostaglandin E2 and bradykinin. Furthermore, binding of prorenin and renin to the prorenin receptor in the collecting duct evokes a number of responses, including the non-proteolytic enzymatic activation of prorenin to produce ANGI from proximal tubule-derived angiotensinogen, which is then converted into ANGII by luminal angiotensin-converting enzyme; stimulation of the epithelial sodium channel (ENaC) in principal cells; and activation of intracellular pathways linked to the upregulation of cyclooxygenase 2 and profibrotic genes. These findings suggest that dysregulation of the renin-angiotensin system in the collecting duct contributes to the development of hypertension by enhancing sodium reabsorption and the progression of kidney injury.

Diabetes mellitus (DM) causes high glucose (HG) levels in the plasma and urine. The (pro)renin receptor (PRR) is a key regulator of renal Na + handling. PRR is expressed in intercalated (IC) cells of the collecting duct (CD) and binds renin to promote angiotensin (Ang) II formation, thereby contributing to Na + reabsorption. In DM, the Kreb's cycle is in a state of suppression in most tissues. However, in the CD, expression of glucose transporters is augmented, boosting the Kreb's cycle and consequently causing α-ketoglutarate (αKG) accumulation. The αKG receptor 1 (OXGR1) is a Gq-coupled receptor expressed on the apical membrane of IC cells of the CD. We hypothesize that HG causes αKG secretion and activation of OXGR1, which increases PRR expression in CD cells. This effect then promotes intratubular AngII formation and Na + reabsorption. To test this hypothesis, streptozotocin (STZ)-induced diabetic mice were treated with or without montelukast (ML), an OXGR1 antagonist, for 6 days. STZ mice had higher urinary αKG and PRR expression along with augmented urinary AngII levels and Na + retention. Treatment with ML prevented all these effects. Similarly, primary cultured inner medullary CD cells treated with HG showed increased PRR expression, while OXGR1 antagonist prevented this effect. αKG increases PRR expression, while treatments with ML, PKC inhibition, or intracellular Ca 2+ depletion impair this effect. In silico analysis suggested that αKG binds to mouse OXGR1. These results indicate that HG conditions promote increased levels of intratubular αKG and OXGR1-dependent PRR upregulation, which impact AngII formation and Na + reabsorption., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Guerrero, Visniauskas, Cárdenas, Figueroa, Vivanco, Salinas-Parra, Araos, Nguyen, Kassan, Amador, Prieto and Gonzalez.)

Background: The soluble prorenin receptor (sPRR), a member of the renin-angiotensin system (RAS), is elevated in plasma of patients with preeclampsia, hypertension, chronic kidney disease (CKD), and type 2 diabetes. Our goal was to examine the relationship between sPRR and RAS activation to define whether sexual dimorphisms in sPRR might explain sex disparities in renal outcomes in patients with type 2 diabetes., Methods: Two hundred sixty-nine participants were included in the study (mean age, 48 ± 16 years; 42% men, 58% women), including 173 controls and 96 subjects with type 2 diabetes. In plasma and urine, we measured sPRR, plasma renin activity (PRA), and prorenin. In the urine, we also measured angiotensinogen along with other biomarkers of renal dysfunction., Results: Plasma sPRR and PRA were significantly higher in women with type 2 diabetes compared to men. In these women, plasma sPRR was positively correlated with PRA, age, and body mass index (BMI). In contrast, in men the sPRR in urine but not in plasma positively correlated with eGFR in urine, but negatively correlated with urine renin activity, plasma glucose, age, and BMI., Conclusions: In patients with type 2 diabetes, sPRR contributes to RAS stimulation in a sex-dependent fashion. In diabetic women, increased plasma sPRR parallels the activation of systemic RAS; while in diabetic men, decreased sPRR in urine matches intrarenal RAS stimulation. sPRR might be a potential indicator of intrarenal RAS activation and renal dysfunction in men and women with type 2 diabetes.

In the kidney, the stimulation of renin production by the collecting duct (CD-renin) contributes to the development of hypertension. The CD is a major nephron segment for the synthesis of nitric oxide (NO), and low NO bioavailability in the renal medulla is associated with hypertension. However, it is unknown whether NO regulates renin production in the CD. To test the hypothesis that low intrarenal NO levels stimulate the production of CD-renin, we first examined renin expression in the distal nephron segments of CD-eNOS deficient mice. In these mice, specific CD-renin immunoreactivity was increased compared to wild-type littermates; however, juxtaglomerular (JG) renin was not altered. To further assess the intracellular mechanisms involved, we then treated M-1 cells with either 1 mM L-NAME (L-arginine analog), an inhibitor of NO synthase activity, or 1 mM NONOate, a NO donor. Both treatments increased intracellular renin protein levels in M-1 cells. However, only the inhibition of NOS with L-NAME stimulated renin synthesis and secretion as reflected by the increase in Ren1C transcript and renin protein levels in the extracellular media, respectively. In addition, NONOate induced a fast mobilization of cGMP and intracellular renin accumulation. These response was partially prevented by guanylyl cyclase inhibition with ODQ (1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1]. Accumulation of intracellular renin was blocked by protein kinase G (PKG) and protein kinase C (PKC) inhibitors. Our data indicate that low NO bioavailability increases CD-renin synthesis and secretion, which may contribute to the activation of intrarenal renin angiotensin system., (Copyright © 2020 Curnow, Gonsalez, Gogulamudi, Visniauskas, Simon, Gonzalez, Majid, Lara and Prieto.)

Aim of the Study: During type 2 diabetes (T2D) and hypertension there is stimulation of renal proximal tubule angiotensinogen (AGT), but whether urinary excretion of AGT (uAGT) is an indicator of glomerular damage or intrarenal RAS activation is unclear. We tested the hypothesis that elevations in uAGT can be detected in the absence of albuminuria in a mouse model of T2D., Methods: Male C57BL/6 mice (N = 10) were fed a high fat (HFD; 45% Kcal from fat) for 28 weeks, and the metabolic phenotype including body weight, blood pressures, glucose, insulin, ippGTT, HOMA-IR, and cholesterol was examined. In addition, kidney Ang II content and reactive oxygen species (ROS) was measured along with urinary albumin, creatinine, Ang II, and AGT., Results: All parameters consistent with T2D were present in mice after 12-14 weeks on the HFD. Systolic BP increased after 18 weeks in HFD but not NFD mice. Intrarenal ROS and Ang II concentrations were also increased in HFD mice. Remarkably, these changes paralleled the augmentation uAGT excretion (3.66 ± 0.50 vs. 0.92 ± 0.13 ng/mg by week 29; P < 0.01), which occurred in the absence of overt albuminuria., Conclusions: In HFD-induced T2D mice, increases in uAGT occur in the absence of overt renal injury, indicating that this biomarker accurately detects early intrarenal RAS activation., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Potato common scab is a worldwide disease mainly caused by Streptomyces scabiei. It seriously affects potato crops by decreasing tuber quality. Essential oils (EO) are natural products with recognised antimicrobial properties. In this research, the antibacterial activities of thyme, oregano, suico and mint EO against S. scabiei were analysed. Infected tubers and soil samples were used for bacterial isolation; the obtained isolates were genetically identified. The chemical composition of the EO was determined by GC-MS. The broth microdilution method was used to analyse antibacterial properties of EO. Thirty-one bacterial isolates were obtained. The isolate chosen for antibacterial assays was morpho-physiologically and genetically identified as S. scabiei. Thyme EO was mainly composed of thymol and o-cymene; suico EO of dihydrotagetone, trans-tagetone and verbenone; oregano EO of trans-sabinene hydrate, thymol and ɣ-terpinene; and mint EO of menthone and menthol. All the EO tested were effective against S. scabiei, but thyme and suico EO were the most successful, with a minimum inhibitory concentration of 0.068 g·l -1 and 0.147 g·l -1 , respectively, and a minimum bactericidal concentration of 0.137 g·l -1 and 0.147 g·l -1 , respectively. Scanning electron microscopy showed similar damage caused by both thyme and suico EO to the bacterial envelope. Total phenolic content of EO was not related to their antibacterial activity. Thyme and suico EO are effective antibacterial agents against S. scabiei, impeding bacterial viability and disturbing the bacterial cell envelope. These EO are promising tools for control of potato common scab., (© 2019 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.)

Acute kidney injury (AKI) is defined as a decrease in kidney function within hours, which encompasses both injury and impairment of renal function. AKI is not considered a pathological condition of single organ failure, but a syndrome in which the kidney plays an active role in the progression of multi-organ dysfunction. The incidence rate of AKI is increasing and becoming a common (8-16% of hospital admissions) and serious disease (four-fold increased hospital mortality) affecting public health costs worldwide. AKI also affects the young and previously healthy individuals affected by infectious diseases in Latin America. Because of the multifactorial pathophysiological mechanisms, there is no effective pharmacological therapy that prevents the evolution or reverses the injury once established; therefore, renal replacement therapy is the only current alternative available for renal patients. The awareness of an accurate and prompt recognition of AKI underlying the various clinical phenotypes is an urgent need for more effective therapeutic interventions to diminish mortality and socio-economic impacts of AKI. The use of biomarkers as an indicator of the initial stage of the disease is critical and the cornerstone to fulfill the gaps in the field. This review discusses emerging strategies from basic science toward the anticipation of features, treatment of AKI, and new treatments using pharmacological and stem cell therapies. We will also highlight bioartificial kidney studies, addressing the limitations of the development of this innovative technology., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Indirect evidence suggests that angiotensin 1-7 (Ang1-7) may counterbalance prohypertensive actions of angiotensin II (AngII), via activation of vascular and/or renal tubular receptors to cause vasodilation and natriuresis/diuresis. We examined if Ang1-7 would attenuate the development of hypertension, renal vasoconstriction, and decreased natriuresis in AngII-infused rats and evaluated the mechanisms involved., Methods: AngII, alone or with Ang1-7, was infused to conscious Sprague-Dawley rats for 13 days and systolic blood pressure (SBP) and renal excretion were repeatedly determined. In anesthetized rats, acute actions of Ang1-7 and effects of blockade of angiotensin AT1 or Mas receptors (candesartan or A-779) were studied., Results: Chronic AngII infusion increased SBP from 143 ± 4 to 195 ± 6 mm Hg. With Ang1-7 co-infused, SBP increased from 133 ± 5 to 161 ± 5 mm Hg (increase reduced, P < 0.002); concurrent increases in urine flow (V) and sodium excretion (UNaV) were greater. In anesthetized normotensive or AngII-induced hypertensive rats, Ang1-7 infusion transiently increased mean arterial pressure (MABP), transiently decreased renal blood flow (RBF), and caused increases in UNaV and V. In normotensive rats, candesartan prevented the Ang1-7-induced increases in MABP and UNaV and the decrease in RBF. In anesthetized normotensive, rats intravenous A-779 increased MABP (114 ± 5 to 120 ± 5 mm Hg, P < 0.03) and urine flow. Surprisingly, these changes were not observed with A-779 applied during background Ang1-7 infusion., Conclusions: The results suggest that in AngII-dependent hypertension, Ang1-7 deficit contributes to sodium and fluid retention and thereby to BP elevation; a correction by Ang1-7 infusion seems mediated by AT1 and not Mas receptors.

Since the prorenin receptor (PRR) was first reported, its physiological role in many cellular processes has been under intense scrutiny. The PRR is currently recognized as a multifunctional receptor with major roles as an accessory protein of the vacuolar-type H + -ATPase and as an intermediary in the Wnt signaling pathway. As a member of the renin-angiotensin system (RAS), the PRR has demonstrated to be of relevance in cardiovascular diseases (CVD) because it can activate prorenin and enhance the enzymatic activity of renin, thus promoting angiotensin II formation. Indeed, there is an association between PRR gene polymorphisms and CVD. Independent of angiotensin II, the activation of the PRR further stimulates intracellular signals linked to fibrosis. Studies using tissues and cells from a variety of organs and systems have supported its roles in multiple functions, although some remain controversial. In the brain, the PRR appears to be involved in the central regulation of blood pressure via activation of RAS- and non-RAS-dependent mechanisms. In the heart, the PRR promotes atrial structural and electrical remodeling. Nonetheless, animals overexpressing the PRR do not exhibit cardiac injury. In the kidney, the PRR is involved in the development of ureteric bud branching, urine concentration, and regulation of blood pressure. There is great interest in the PRR contributions to T cell homeostasis and to the development of visceral and brown fat. In this mini-review, we discuss the evidence for the pathophysiological roles of the PRR with emphasis in CVD.

Renal ischemia-reperfusion injury (IRI) is a major cause of acute renal failure. Doxycycline (Dc) belongs to the tetracycline-class of antibiotics with demonstrated beneficial molecular effects in the brain and heart, mainly through matrix metalloproteinases inhibition (MMP). However, Dc protection of renal function has not been demonstrated. We determined whether low doses of Dc would prevent decreases in glomerular filtration rate (GFR) and maintain tubular Na + handling in Wistar rats subjected to kidney I/R. Male Wistar rats underwent bilateral kidney ischemia for 30min followed by 24h reperfusion (I/R). Doxycycline (1, 3, and 10mg/kg, i.p.) was administered 2h before surgery. Untreated I/R rats showed a 250% increase in urine volume and proteinuria, a 60% reduction in GFR, accumulation of urea-nitrogen in the blood, and a 60% decrease in the fractional Na + excretion due to unbalanced Na + transporter activity. Treatment with Dc 3mg/kg maintained control levels of urine volume, proteinuria, GFR, blood urea-nitrogen, fractional Na + excretion, and equilibrated Na + transporter activities. The Dc protection effects on renal function were associated with kidney structure preservation and prevention of TGFβ and fibronectin deposition. In vitro, total MMP activity was augmented in I/R and inhibited by 25 and 50μM Dc. In vivo, I/R augmented MMP-2 and -9 protein content without changing their activities. Doxycycline treatment downregulated total MMP activity and MMP-2 and -9 protein content. Our results suggest that treatment with low dose Dc protects from IRI, thereby preserving kidney function., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Serelaxin is a novel recombinant human relaxin-2 that has been investigated for the treatment of acute heart failure. However, its effects on renal function, especially on the renal microcirculation, remain incompletely characterized. Our immunoexpression studies localized RXFP1 receptors on vascular smooth muscle cells and endothelial cells of afferent arterioles and on principal cells of collecting ducts. Clearance experiments were performed in male and female normotensive rats and Ang II-infused male rats. Serelaxin increased mean arterial pressure slightly and significantly increased renal blood flow, urine flow, and sodium excretion rate. Group analysis of all serelaxin infusion experiments showed significant increases in GFR. During infusion with subthreshold levels of Ang II, serelaxin did not alter mean arterial pressure, renal blood flow, GFR, urine flow, or sodium excretion rate. Heart rates were elevated during serelaxin infusion alone (37 ± 5%) and in Ang II-infused rats (14 ± 2%). In studies using the in vitro isolated juxtamedullary nephron preparation, superfusion with serelaxin alone (40 ng/ml) significantly dilated afferent arterioles (10.8 ± 1.2 vs. 13.5 ± 1.1 µm) and efferent arterioles (9.9 ± 0.9 vs. 11.9 ± 1.0 µm). During Ang II superfusion, serelaxin did not alter afferent or efferent arteriolar diameters. During NO synthase inhibition (l-NNA), afferent arterioles also did not show any vasodilation during serelaxin infusion. In conclusion, serelaxin increased overall renal blood flow, urine flow, GFR, and sodium excretion and dilated the afferent and efferent arterioles in control conditions, but these effects were attenuated or prevented in the presence of exogenous Ang II and NO synthase inhibitors.

Augmented intratubular angiotensin (ANG) II is a key determinant of enhanced distal Na + reabsorption via activation of epithelial Na + channels (ENaC) and other transporters, which leads to the development of high blood pressure (BP). In ANG II-induced hypertension, there is increased expression of the prorenin receptor (PRR) in the collecting duct (CD), which has been implicated in the stimulation of the sodium transporters and resultant hypertension. The impact of PRR deletion along the nephron on BP regulation and Na + handling remains controversial. In the present study, we investigate the role of PRR in the regulation of renal function and BP by using a mouse model with specific deletion of PRR in the CD ( CD PRR-KO). At basal conditions, CD PRR-KO mice had decreased renal function and lower systolic BP associated with higher fractional Na + excretion and lower ANG II levels in urine. After 14 days of ANG II infusion (400 ng·kg -1 ·min -1 ), the increases in systolic BP and diastolic BP were mitigated in CD PRR-KO mice. CD PRR-KO mice had lower abundance of cleaved αENaC and γENaC, as well as lower ANG II and renin content in urine compared with wild-type mice. In isolated CD from CD PRR-KO mice, patch-clamp studies demonstrated that ANG II-dependent stimulation of ENaC activity was reduced because of fewer active channels and lower open probability. These data indicate that CD PRR contributes to renal function and BP responses during chronic ANG II infusion by enhancing renin activity, increasing ANG II, and activating ENaC in the distal nephron segments., (Copyright © 2017 the American Physiological Society.)

Recent studies suggested that activation of the PRR upregulates profibrotic markers through reactive oxygen species (ROS) formation; however, the exact mechanisms have not been investigated in CD cells. We hypothesized that activation of the PRR increases the expression of profibrotic markers through MAPK-dependent ROS formation in CD cells. Mouse renal CD cell line (M-1) was treated with recombinant prorenin plus ROS or MAPK inhibitors and PRR-shRNA to evaluate their effect on the expression of profibrotic markers. PRR immunostaining revealed plasma membrane and intracellular localization. Recombinant prorenin increases ROS formation (6.0 ± 0.5 vs 3.9 ± 0.1 nmol/L DCF/μg total protein, P < .05) and expression of profibrotic markers CTGF (149 ± 12%, P < .05), α-SMA (160 ± 20%, P < .05), and PAI-I (153 ± 13%, P < .05) at 10 -8  mol/L. Recombinant prorenin-induced phospho ERK 1/2 (p44 and p42) at 10 -8 and 10 -6  mol/L after 20 minutes. Prorenin-dependent ROS formation and augmentation of profibrotic factors were blunted by ROS scavengers (trolox, p-coumaric acid, ascorbic acid), the MEK inhibitor PD98059 and PRR transfections with PRR-shRNA. No effects were observed in the presence of antioxidants alone. Prorenin-induced upregulation of collagen I and fibronectin was blunted by ROS scavenging or MEK inhibition independently. PRR-shRNA partially prevented this induction. After 24 hours prorenin treatment M-1 cells undergo to epithelial-mesenchymal transition phenotype, however MEK inhibitor PD98059 and PRR knockdown prevented this effect. These results suggest that PRR might have a significant role in tubular damage during conditions of high prorenin-renin secretion in the CD., (© 2017 John Wiley & Sons Australia, Ltd.)

During the early phase of ANG II-dependent hypertension, tubular PGE 2 is increased. Renin synthesis and secretion in the collecting duct (CD) are upregulated by ANG II, contributing to further intratubular ANG II formation. However, what happens first and whether the triggering mechanism is independent of tubular ANG II remain unknown. PGE 2 stimulates renin synthesis in juxtaglomerular cells via E-prostanoid (EP) receptors through the cAMP/cAMP-responsive element-binding (CREB) pathway. EP receptors are also expressed in the CD. Here, we tested the hypothesis that renin is upregulated by PGE 2 in CD cells. The M-1 CD cell line expressed EP1, EP3, and EP4 but not EP2. Dose-response experiments, in the presence of ANG II type 1 receptor blockade with candesartan, demonstrated that 10 -6 M PGE 2 maximally increases renin mRNA (approximately 4-fold) and prorenin/renin protein levels (approximately 2-fold). This response was prevented by micromolar doses of SC-19220 (EP1 antagonist), attenuated by the EP4 antagonist, L-161982, and exacerbated by the highly selective EP3 antagonist, L-798106 (~10-fold increase). To evaluate further the signaling pathway involved, we used the PKC inhibitor calphostin C and transfections with PKCα dominant negative. Both strategies blunted the PGE 2 -induced increases in cAMP levels, CREB phosphorylation, and augmentation of renin. Knockdown of the EP1 receptor and CREB also prevented renin upregulation. These results indicate that PGE 2 increases CD renin expression through the EP1 receptor via the PKC/cAMP/CREB pathway. Therefore, we conclude that during the early stages of ANG II-dependent hypertension, there is augmentation of PGE 2 that stimulates renin in the CD, resulting in increased tubular ANG II formation and further stimulation of renin., (Copyright © 2017 the American Physiological Society.)

Background: Prostaglandin E2 (PGE 2 ) regulates renin expression in renal juxtaglomerular cells. PGE 2 acts through E-prostanoid (EP) receptors in the renal collecting duct (CD) to regulate sodium and water balance. CD cells express EP1 and EP4, which are linked to protein kinase C (PKC) and PKA downstream pathways, respectively. Previous studies showed that the presence of renin in the CD, and that of PKC and PKA pathways, activate its expression. The (pro)renin receptor (PRR) is also expressed in CD cells, and its activation enhances cyclooxygenase-2 (COX-2) through extracellular signal-regulated kinase (ERK). We hypothesized that PGE 2 stimulates prorenin and renin synthesis leading to subsequent activation of PRR and upregulation of COX-2., Methods: We used a mouse M-1 CD cell line that expresses EP1, EP3 and EP4 but not EP2., Results: PGE 2 (10 -6 M) treatment increased prorenin and renin protein levels at 4 and 8 hours. No differences were found at 12-hour after PGE 2 treatment. Phospho-ERK was significantly augmented after 12 hours. COX-2 expression was decreased after 4 hours of PGE 2 treatment, but increased after 12 hours. Interestingly, the full-length form of the PRR was upregulated only at 12 hours. PGE 2 -mediated phospho-ERK and COX-2 upregulation was suppressed by PRR silencing., Conclusions: Our results suggest that PGE 2 induces biphasic regulation of COX-2 through renin-dependent PRR activation via EP1 and EP4 receptors. PRR-mediated increases in COX-2 expression may enhance PGE 2 synthesis in CD cells serving as a buffer mechanism in conditions of activated renin-angiotensin system., (Copyright © 2017 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.)

The presence of renin production by the principal cells of the collecting duct has opened new perspectives for the regulation of intrarenal angiotensin II (Ang II). Angiotensinogen (AGT) and angiotensin-converting enzyme (ACE) are present in the tubular fluid coming from the proximal tubule and collecting duct. All the components needed for Ang II formation are present along the nephron, and much is known about the mechanisms regulating renin in juxtaglomerular cells (JG); however, those in the collecting duct remain unclear. Ang II suppresses renin via protein kinase C (PKC) and calcium (Ca 2+ ) in JG cells, but in the principal cells, Ang II increases renin synthesis and release through a pathophysiological mechanism that increases further intratubular Ang II de novo formation to enhance distal Na + reabsorption. Transgenic mice overexpressing renin in the collecting duct demonstrate the role of collecting duct renin in the development of hypertension. The story became even more interesting after the discovery of a specific receptor for renin and prorenin: the prorenin receptor ((P)RR), which enhances renin activity and fully activates prorenin. The interactions between (P)RR and prorenin/renin may further increase intratubular Ang II levels. In addition to Ang II, other mechanisms have been described in the regulation of renin in the collecting duct, including vasopressin (AVP), bradykinin (BK), and prostaglandins. Current active investigations are aimed at elucidating the mechanisms regulating renin in the distal nephron segments and understand its role in the pathogenesis of hypertension.

Background: Sexual difference has been shown in the pathogenesis of chronic kidney disease induced by hypertension. Females are protected from hypertension and related end-organ damage. Augmentation of renal proximal tubular angiotensinogen (AGT) expression can promote intrarenal angiotensin formation and the development of associated hypertension and kidney injury. Female rodents exhibit lower intrarenal AGT levels than males under normal conditions, suggesting that the suppressed intrarenal AGT production by programmed mechanisms in females may provide protection from these diseases. This study was performed to examine whether epigenetic mechanisms serve as repressors of AGT., Methods: Male and female Sprague Dawley rats were used to investigate sex differences of systemic, hepatic, and intrarenal AGT levels. All histone deacetylase (HDAC) mRNA levels in the kidneys were determined using a PCR array. HDAC9 protein expression in the kidneys and cultured renal proximal tubular cells (PTC) was analyzed by Western blot analysis and immunohistochemistry. The effects of HDAC9 on AGT expression were evaluated by using an inhibitor and siRNA. ChIP assay was performed to investigate the interaction between the AGT promoter and HDAC9., Results: Plasma and liver AGT levels did not show differences between male and female Sprague-Dawley rats. In contrast, females exhibited lower AGT levels than males in the renal cortex and urine. In the absence of supplemented sex hormones, primary cultured renal cortical cells isolated from female rats sustained lower AGT levels than those from males, suggesting that the kidneys have a unique mechanism of AGT regulation controlled by epigenetic factors rather than sex hormones. HDAC9 mRNA and protein levels were higher in the renal cortex of female rats versus male rats (7.09 ± 0.88, ratio to male) while other HDACs did not exhibit a sex difference. HDAC9 expression was localized in PTC which are the primary source of intrarenal AGT. Importantly, HDAC9 knockdown augmented AGT mRNA (1.92 ± 0.35-fold) and protein (2.25 ± 0.50-fold) levels, similar to an HDAC9 inhibitor. Furthermore, an interaction between HDAC9 and a distal 5' flanking region of AGT via a histone complex containing H3 and H4 was demonstrated., Conclusions: These results indicate that HDAC9 is a novel suppressing factor involved in AGT regulation in PTC, leading to low levels of intrarenal AGT in females. These findings will help to delineate mechanisms underlying sex differences in the development of hypertension and renin-angiotensin system (RAS) associated kidney injury.

In the collecting duct (CD), the interactions of renin angiotensin system (RAS) and kallikrein-kinin system (KKS) modulate Na + reabsorption, volume homeostasis, and blood pressure. In this study, we used a mouse kidney cortical CD cell line (M-1 cells) to test the hypothesis that in the CD, the activation of bradykinin B 2 receptor (B 2 R) increases renin synthesis and release. Physiological concentrations of bradykinin (BK) treatment of M-1 cells increased renin mRNA and prorenin and renin protein contents in a dose-dependent manner and increased threefold renin content in the cell culture media. These effects were mediated by protein kinase C (PKC) independently of protein kinase A (PKA) because B 2 R antagonism with Icatibant and PKC inhibition with calphostin C, prevented these responses, but PKA inhibition with H89 did not modify the effects elicited by the B 2 R activation. BK-dependent stimulation of renin gene expression in CD cells also involved nitric oxide (NO) pathway because increased cGMP levels and inhibition of NO synthase with L-NAME prevented it. Complementary renin immunohistochemical studies performed in kidneys from mice with conventional B 2 R knockout and conditional B 2 R knockout in the CD, showed marked decreased renin immunoreactivity in CD, regardless of the renin presence in juxtaglomerular cells in the knockout mice. These results indicate that the activation of B 2 R increases renin synthesis and release by the CD cells through PKC stimulation and NO release, which support further the interactions between the RAS and KKS., (© 2017 Tulane University. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.)

In angiotensin II (ANG II)-dependent hypertension, there is an angiotensin type 1 receptor-dependent amplification mechanism enhancing intrarenal angiotensinogen (AGT) formation and secretion in the tubular fluid. To evaluate the role of increased arterial pressure, AGT mRNA, protein expression, and urinary AGT (uAGT) excretion and tissue injury were assessed in both kidneys of two-kidney, one-clip Sprague-Dawley hypertensive rats subjected to left renal arterial clipping (0.25-mm gap). By 18-21 days, systolic arterial pressure increased to 180 ± 3 mmHg, and uAGT increased. Water intake, body weights, 24-h urine volumes, and sodium excretion were similar. In separate measurements of renal function in anesthetized rats, renal plasma flow and glomerular filtration rate were similar in clipped and nonclipped kidneys and not different from those in sham rats, indicating that the perfusion pressure to the clipped kidneys remained within the autoregulatory range. The nonclipped kidneys exhibited increased urine flow and sodium excretion. The uAGT excretion was significantly greater in nonclipped kidneys compared with clipped and sham kidneys. AGT mRNA was 2.15-fold greater in the nonclipped kidneys compared with sham (1.0 ± 0.1) or clipped (0.98 ± 0.15) kidneys. AGT protein levels were also greater in the nonclipped kidneys. The nonclipped kidneys exhibited greater glomerular expansion and immune cell infiltration, medullary fibrosis, and cellular proliferation than the clipped kidneys. Because both kidneys have elevated ANG II levels, the greater tissue injury in the nonclipped kidneys indicates that an increased arterial pressure synergizes with increased intrarenal ANG II to stimulate AGT production and exert greater renal injury., (Copyright © 2016 the American Physiological Society.)

Pulmonary hypertension is a rare disorder that, without treatment, is progressive and fatal within 3-4 years. Current treatment involves a diverse group of drugs that target the pulmonary vascular bed. In addition, strategies that increase nitric oxide (NO) formation have a beneficial effect in rodents and patients. Nebivolol, a selective β1 adrenergic receptor-blocking agent reported to increase NO production and stimulate β3 receptors, has vasodilator properties suggesting that it may be beneficial in the treatment of pulmonary hypertension. The present study was undertaken to determine whether nebivolol has a beneficial effect in monocrotaline-induced (60 mg/kg) pulmonary hypertension in the rat. These results show that nebivolol treatment (10 mg/kg, once or twice daily) attenuates pulmonary hypertension, reduces right ventricular hypertrophy, and improves pulmonary artery remodeling in monocrotaline-induced pulmonary hypertension. This study demonstrates the presence of β3 adrenergic receptor immunoreactivity in pulmonary arteries and airways and that nebivolol has pulmonary vasodilator activity. Studies with β3 receptor agonists (mirabegron, BRL 37344) and antagonists suggest that β3 receptor-mediated decreases in systemic arterial pressure occur independent of NO release. Our results suggest that nebivolol, a selective vasodilating β1 receptor antagonist that stimulates β3 adrenergic receptors and induces vasodilation by increasing NO production, may be beneficial in treating pulmonary hypertensive disorders.

Objective:: To identify pediatric caregivers' reactions in outpatient surgery settings., Methods:: A quantitative descriptive/exploratory survey-based study involving application of a semi-structured questionnaire to 62 caregivers in two hospitals., Results:: Most caregivers (88.7%) were mothers who submitted to preoperative fasting with their children. Nervousness, anxiety and concern were the most common feelings reported by caregivers on the day of the surgery., Conclusion:: Medical instructions regarding preoperative procedures had significant positive impacts on patient care, and on patient and caregiver stress levels., Objetivo:: Identificar as reações dos acompanhantes de crianças submetidas à cirurgia ambulatorial., Métodos:: Estudo survey descritivo/ exploratório, de caráter quantitativo, realizado em dois hospitais com 62 acompanhantes que responderam um questionário semiestruturado., Resultados:: Constatou-se que a maioria dos acompanhantes era formada por mães (88,7%) e permaneceu em jejum junto das crianças. Todos os acompanhantes referiram sentimentos identificados como nervosismo, ansiedade e preocupação., Conclusão:: A orientação médica aos procedimentos pré-operatórios foi de grande importância, não somente para o cuidado da criança, mas também do acompanhante, visando diminuir ao máximo o estresse vivenciado por eles., Competing Interests: none.

Renin is synthesized in the principal cells of the collecting duct (CD), and its production is increased via cAMP in angiotensin (ANG) II-dependent hypertension, despite suppression of juxtaglomerular (JG) renin. Vasopressin, one of the effector hormones of the renin-angiotensin system (RAS) via the type 2-receptor (V2R), activates the cAMP/PKA/cAMP response element-binding protein (CREB) pathway and aquaporin-2 expression in principal cells of the CD. Accordingly, we hypothesized that activation of V2R increases renin synthesis via PKA/CREB, independently of ANG II type 1 (AT1) receptor activation in CD cells. Desmopressin (DDAVP; 10(-6) M), a selective V2R agonist, increased renin mRNA (∼3-fold), prorenin (∼1.5-fold), and renin (∼2-fold) in cell lysates and cell culture media in the M-1 CD cell line. Cotreatment with DDAVP+H89 (PKA inhibitor) or CREB short hairpin (sh) RNA prevented this response. H89 also blunted DDAVP-induced CREB phosphorylation and nuclear localization. In 48-h water-deprived (WD) mice, prorenin-renin protein levels were increased in the renal inner medulla (∼1.4- and 1.8-fold). In WD mice treated with an ACE inhibitor plus AT1 receptor blockade, renin mRNA and prorenin protein levels were still higher than controls, while renin protein content was not changed. In M-1 cells, ANG II or DDAVP increased prorenin-renin protein levels; however, there were no further increases by combined treatment. These results indicate that in the CD the activation of the V2R stimulates renin synthesis via the PKA/CREB pathway independently of RAS, suggesting a critical role for vasopressin in the regulation of renin in the CD., (Copyright © 2016 the American Physiological Society.)

In contrast to the negative feedback of angiotensin II (ANG II) on juxtaglomerular renin, ANG II stimulates renin in the principal cells of the collecting duct (CD) in rats and mice via ANG II type 1 (AT1R) receptor, independently of blood pressure. In vitro data indicate that CD renin is augmented by AT1R activation through protein kinase C (PKC), but the exact mechanisms are unknown. We hypothesize that ANG II stimulates CD renin synthesis through AT1R via PKC and the subsequent activation of cAMP/PKA/CREB pathway. In M-1 cells, ANG II increased cAMP, renin mRNA (3.5-fold), prorenin, and renin proteins, as well as renin activity in culture media (2-fold). These effects were prevented by PKC inhibition with calphostin C, PKC-α dominant negative, and by PKA inhibition. Forskolin-induced increases in cAMP and renin expression were prevented by calphostin C. PKC inhibition and Ca2+ depletion impaired ANG II-mediated CREB phosphorylation and upregulation of renin. Adenylate cyclase 6 (AC) siRNA remarkably attenuated the ANG II-dependent upregulation of renin mRNA. Physiological activation of AC with vasopressin increased renin expression in M-1 cells. The results suggest that the ANG II-dependent upregulation of renin in the CD depends on PKC-α, which allows the augmentation of cAMP production and activation of PKA/CREB pathway via AC6. This study defines the intracellular signaling pathway involved in the ANG II-mediated stimulation of renin in the CD. This is a novel mechanism responsible for the regulation of local renin-angiotensin system in the distal nephron., (Copyright © 2015 the American Physiological Society.)

In angiotensin (Ang)-II-dependent hypertension, collecting duct renin synthesis and secretion are stimulated despite suppression of juxtaglomerular (JG) renin. This effect is mediated by Ang II type 1 (AT1) receptor independent of blood pressure. Although the regulation of JG renin is known, the mechanisms by which renin is regulated in the collecting duct are not completely understood. The presence of renin activity in the collecting duct may provide a pathway for intratubular Ang II formation since angiotensinogen substrate and angiotensin converting enzyme are present in the distal nephron. The recently named new member of the renin-angiotensin system (RAS), the (pro)renin receptor [(P)RR], is able to bind renin and the inactive prorenin, thus enhancing renin activity and fully activating prorenin. We have demonstrated that renin and (P)RR are augmented in renal tissues from rats infused with Ang II and during sodium depletion, suggesting a physiological role in intrarenal RAS activation. Importantly, (P)RR activation also causes activation of intracellular pathways associated with increased cyclooxygenase 2 expression and induction of profibrotic genes. In addition, renin and (P)RR are upregulated by Ang II in collecting duct cells. Although the mechanisms involved in their regulation are still under study, they seem to be dependent on the intrarenal RAS activation. The complexities of the mechanisms of stimulation also depend on cyclooxygenase 2 and sodium depletion. Our data suggest that renin and (P)RR can interact to increase intratubular Ang II formation and the activation of profibrotic genes in renal collecting duct cells. Both pathways may have a critical role in the development of hypertension and renal disease., (© The Author(s), 2015.)

Transcription factor E26 transformation-specific sequence-1 (ETS-1) is a transcription factor that regulates the expression of a variety of genes, including growth factors, chemokines, and adhesion molecules. We recently demonstrated that angiotensin II increases the glomerular expression of ETS-1 and that blockade of ETS-1 ameliorates the profibrotic and proinflammatory effects of angiotensin II. The Dahl salt-sensitive rat is a paradigm of salt-sensitive hypertension associated with local activation of the renin-angiotensin system. In these studies, we determined whether: (1) salt-sensitive hypertension is associated with renal expression of ETS-1 and (2) ETS-1 participates in the development of end-organ injury in salt-sensitive hypertension. Dahl salt-sensitive rats were fed a normal-salt diet (0.5% NaCl diet) or a high-salt diet (4% NaCl) for 4 weeks. Separate groups on high-salt diet received an ETS-1 dominant-negative peptide (10 mg/kg/d), an inactive ETS-1 mutant peptide (10 mg/kg/d), the angiotensin II type 1 receptor blocker candesartan (10 mg/kg/d), or the combination high-salt diet/dominant-negative peptide/angiotensin II type 1 receptor blocker for 4 weeks. High-salt diet rats had a significant increase in the glomerular expression of the phosphorylated ETS-1 that was prevented by angiotensin II type 1 receptor blocker. ETS-1 blockade reduced proteinuria, glomerular injury score, fibronectin expression, urinary transforming growth factor-β excretion, and macrophage infiltration. Angiotensin II type 1 receptor blocker reduced proteinuria, glomerular injury score, and macrophage infiltration, whereas concomitant ETS-1 blockade and angiotensin II type 1 receptor blocker had additive effects and reduced interstitial fibrosis. Our studies demonstrated that salt-sensitive hypertension results in increased glomerular expression of phosphorylated ETS-1 and suggested that ETS-1 plays an important role in the pathogenesis of end-organ injury in salt-sensitive hypertension., (© 2015 American Heart Association, Inc.)