The interaction between hippocampal cholinergic and nitrergic neurotransmission coordinates NMDA-dependent behavior and autonomic changes induced by contextual fear retrieval.

RATIONALE: Re-exposing an animal to an environment previously paired with an aversive stimulus evokes large alterations in behavioral and cardiovascular parameters. Dorsal hippocampus (dHC) receives important cholinergic inputs from the basal forebrain, and respective acetylcholine (ACh) levels are described to influence defensive behavior. Activation of muscarinic M1 and M3 receptors facilitates autonomic and behavioral responses along threats. Evidence show activation of cholinergic receptors promoting formation of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) in dHC. Altogether, the action of ACh and NO on conditioned responses appears to converge within dHC. OBJECTIVES: As answer about how ACh and NO interact to modulate defensive responses has so far been barely addressed, we aimed to shed additional light on this topic. METHODS: Male Wistar rats had guide cannula implanted into the dHC before being submitted to the contextual fear conditioning (3footshocks/085 mA/2 s). A catheter was implanted in the femoral artery the next day for cardiovascular recordings. Drugs were delivered into dHC 10 min before contextual re-exposure, which occurred 48 h after the conditioning procedure. RESULTS: Neostigmine (Neo) amplified the retrieval of conditioned responses. Neo effects (1 nmol) were prevented by the prior infusion of a M1-M3 antagonist (fumarate), a neuronal nitric oxide synthase inhibitor (NPLA), a NO scavenger (cPTIO), a guanylyl cyclase inhibitor (ODQ), and a NMDA antagonist (AP-7). Pretreatment with a selective M1 antagonist (pirenzepine) only prevented the increase in autonomic responses induced by Neo. CONCLUSION: The results show that modulation in the retrieval of contextual fear responses involves coordination of the dHC M1-M3/NO/cGMP/NMDA pathway.

The Fumarprotocetraric Acid Inhibits Tau Covalently, Avoiding Cytotoxicity of Aggregates in Cells.

Neurodegenerative disorders, including Tauopathies that involve tau protein, base their pathological mechanism on forming proteinaceous aggregates, which has a deleterious effect on cells triggering an inflammatory response. Moreover, tau inhibitors can exert their mechanism of action through noncovalent and covalent interactions. Thus, Michael's addition appears as a feasible type of interaction involving an α, ß unsaturated carbonyl moiety to avoid pathological confirmation and further cytotoxicity. Moreover, we isolated three compounds from Antarctic lichens Cladonia cariosa and Himantormia lugubris: protolichesterinic acid (1), fumarprotocetraric acid (2), and lichesterinic acid (3). The maleimide cysteine labeling assay showed that compounds 1, 2, and 3 inhibit at 50 µM, but compounds 2 and 3 are statistically significant. Based on its inhibition capacity, we decided to test compound 2 further. Thus, our results suggest that compound 2 remodel soluble oligomers and diminish ß sheet content, as demonstrated through ThT experiments. Hence, we added externally treated oligomers with compound 2 to demonstrate that they are harmless in cell culture. First, the morphology of cells in the presence of aggregates does not suffer evident changes compared to the control. Additionally, the externally added aggregates do not provoke a substantial LDH release compared to the control, indicating that treated oligomers do not provoke membrane damage in cell culture compared with aggregates alone. Thus, in the present work, we demonstrated that Michael's acceptors found in lichens could serve as a scaffold to explore different mechanisms of action to turn tau aggregates into harmless species.

Mitochondrial Signature in Human Monocytes and Resistance to Infection in C. elegans During Fumarate-Induced Innate Immune Training.

Monocytes can develop immunological memory, a functional characteristic widely recognized as innate immune training, to distinguish it from memory in adaptive immune cells. Upon a secondary immune challenge, either homologous or heterologous, trained monocytes/macrophages exhibit a more robust production of pro-inflammatory cytokines, such as IL-1ß, IL-6, and TNF-α, than untrained monocytes. Candida albicans, ß-glucan, and BCG are all inducers of monocyte training and recent metabolic profiling analyses have revealed that training induction is dependent on glycolysis, glutaminolysis, and the cholesterol synthesis pathway, along with fumarate accumulation; interestingly, fumarate itself can induce training. Since fumarate is produced by the tricarboxylic acid (TCA) cycle within mitochondria, we asked whether extra-mitochondrial fumarate has an effect on mitochondrial function. Results showed that the addition of fumarate to monocytes induces mitochondrial Ca2+ uptake, fusion, and increased membrane potential (Δψm), while mitochondrial cristae became closer to each other, suggesting that immediate (from minutes to hours) mitochondrial activation plays a role in the induction phase of innate immune training of monocytes. To establish whether fumarate induces similar mitochondrial changes in vivo in a multicellular organism, effects of fumarate supplementation were tested in the nematode worm Caenorhabditis elegans. This induced mitochondrial fusion in both muscle and intestinal cells and also increased resistance to infection of the pharynx with E. coli. Together, these findings contribute to defining a mitochondrial signature associated with the induction of innate immune training by fumarate treatment, and to the understanding of whole organism infection resistance.

The use of aliskiren as an antifibrotic drug in experimental models: A systematic review.

Aliskiren is an oral antihypertensive medication that acts by directly inhibiting renin. High levels of circulating renin and prorenin activate the pathological signaling pathway of fibrosis. This drug also reduces oxidative stress. Thus, the aim of this systematic review is to analyze experimental studies that show the actions of aliskiren on fibrosis. PubMed and LILACS databases were consulted using the keywords aliskiren and fibrosis within the period between 2005 and 2017. Fifty-three articles were analyzed. In the heart, aliskiren attenuated remodeling, hypertrophy, inflammatory cytokines, collagen deposition, and oxidative stress. In the kidneys, there was a reduction in interstitial fibrosis, the infiltration of inflammatory cells, apoptosis, proteinuria, and in the recruitment of macrophages. In diabetic models, an improvement in the albumin/creatinine relationship and in the insulin pathway in skeletal muscles was observed; aliskiren was beneficial to pancreatic function and glucose tolerance. In the liver, aliskiren reduced fibrosis, steatosis, inflammatory cytokines, and collagen deposition. In the lung and peritoneal tissues, there was a reduction in fibrosis. Many studies have reported on the beneficial effects of aliskiren on endothelial function and arterial rigidity. A reduction in fibrosis in different organs is cited by many authors, which complies with the results found in this review. However, studies diverge on the use of the drug in diabetic patients. Aliskiren has antifibrotic potential in several experimental models, interfering with the levels of fibrogenic cytokines and oxidative stress. Therefore, its use in diseases in which fibrosis plays an important pathophysiological role is suggested.

Aliskiren improves renal morphophysiology and inflammation in Wistar rats with 2K1C renovascular hypertension.

Hypertension is characterized by persistent elevated blood pressure levels, one of the leading causes of death in the world. Renovascular hypertension represents the most common cause of secondary hypertension, and its progress is associated with overactivation of the renin angiotensin aldosterone system (RAAS), causing systemic and local changes. Aliskiren is a renin-inhibiting drug that optimizes RAAS suppression. In this sense, the objective of the present study was to analyze the morphophysiology of the left kidney in Wistar rats with renovascular hypertension after treatment with Aliskiren. Parameters such as systolic blood pressure, urinary creatinine and protein excretion, renal cortex structure and ultrastructure, fibrosis and tissue inflammation were analyzed. Our results showed that the hypertensive animals treated with Aliskiren presented a reestablishment of blood pressure, expression of renin, and renal function, as well as a remodeling of morphological alterations through the reduction of fibrosis. The treatment regulated the laminin expression and decreased pro-inflammatory cytokines, restoring the integrity of the glomerular filtration barrier. Therefore, our findings suggest that Aliskiren has a renoprotective effect acting on the improvement of the morphology, physiology and pathology of the renal cortex of animals with renovascular hypertension.

Matrices based on lineal and star fumarate-metha/acrylate copolymers for bone tissue engineering: Characterization and biocompatibility studies.

This article presents the preparation of matrices from two new families of fumaric copolymers and the effect of structural differences on their physicochemical and biological behavior. Diisopropyl fumarate (DIPF) and poly(ethylene glycol) methyl ether methacrylate (OEGMA) or N-isopropylacrylamide (NIPAM) were copolymerized by conventional radical and RAFT polymerization to obtain lineal or start architectures, respectively. These copolymers were characterized by spectroscopic (FTIR and 1 H-NMR) and chromatographic methods. The thermal stability was studied by thermal gravimetric analysis, showing some differences in relation to the architecture and chemical nature of copolymers. SEM morphological analysis demonstrated that the surface of the matrices derived from OEGMA exhibited an irregular and rough surface, while DIPF-NIPAM copolymers presented smooth surface with nearly no significant porosity. The matrix obtained of both kinds of copolymers presented no cytotoxicity as it was evaluated using a model of macrophages on culture. Moreover, cell growth was better on the surfaces of the DIPF-NIPAM matrices, suggesting a good interaction with this matrix and its potential application as matrices for tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 195-203, 2019.

Effects of Aliskiren, an RAAS inhibitor, on a carrageenan-induced pleurisy model of rats.

Our aim is to investigate the potentially preventive effects of Aliskiren in a carrageenan-induced lung pleurisy model and to compare the standard anti-inflammatory agents, indomethacin and dexamethasone. The pleurisy model was induced through the injection of carrageenan (0.2 ml-%2) into the pleural cavity. After the experiment, serum and lung tissues were collected and biochemical, molecular and pathological examinations were performed. In our study, pleural inflammation decreased superoxide dismutase activity and the glutathione level and increased the malondialdehyde level in the lung of rats, while Aliskiren increased the superoxide dismutase activity and glutathione level and decreased the malondialdehyde level. In addition, carrageenan-induced pleurisy caused a significant increase in pro-inflammatory cytokines mRNA expressions (TNF-α, IL-1ß, and NF-KB), while Aliskiren administration decreased their expressions as well as the standard treatments, indomethacin and dexamethasone, did. Aliskiren administration at the 200 mg/kg dose protected the lungs in the pathological evaluation, especially against inflammatory cell infiltration and edematous lesions. It appears that Aliskiren protects the lung from carrageenan-induced pleurisy damage by regulating inflammation and antioxidant-oxidant balance via Renin Angiotensin Aldosterone System inhibition.

Mast cell population in the development of diabetic nephropathy: Effects of renin angiotensin system inhibition.

Considering the importance of the renin-angiotensin system (RAS) in diabetic nephropathy (DN) and the link between mast cells (MC) and the RAS, this study evaluated the effects of RAS blockade on the MC cell population in the kidneys from rats with experimental diabetes. Wistar rats were divided into six groups: control non-diabetic (C); sham (S); diabetic (D); and D treated with enalapril (EN), losartan (LO), or aliskiren (AL). Ninety days after diabetes induction, glomerular filtration rate (GFR) and urinary albumin excretion (UAE) were determined. Kidneys were collected for MC counting. RAS blockers minimized changes in morphometrical parameters (EN), cortical collagen (LO, AL), GFR (AL) and UAE (EN, LO). An increased number of MC was observed in the kidneys from D animals. Only AL treatment prevented this increase. MC may be involved in some aspects of DN pathogenesis and the possible protective effects of AL on the kidneys might involve MC modulation.

The comparative efficacy of renin-angiotensin system blockers in schistosomal hepatic fibrosis.

Schistosomiasis mansoni is involved in hepatic fibrogenesis and portal hypertension. Previous studies proved that blockade of some components of the renin-angiotensin system (RAS) reduce liver fibrogenesis. However, the effects of inhibition of early stages of RAS pathway in schistosomal fibrosis have not been studied yet. Thus, the aim of this study was to compare the role of different antihypertensive drugs on hepatic fibrosis in murine schistosomiasis. BALB/c mice (n = 50) weighing 20g were subjected to inoculation of 50 cercariae and submitted to different treatments: aliskiren, 50 mg/kg (n = 10); bradykinin, 2 µg/kg (n = 5); losartan, 10 mg/kg (n = 10); lisinopril 10 mg/kg (n = 5) and control, proportional volume vehicle (n = 5); daily for 14 weeks. Six animals were not subjected to cercariae inoculation or any type of treatment. Ultrasound, histological, immunohistochemical and proteomic analyzes were performed to evaluate markers associated with hepatic fibrogenesis. The hepatic areas stained with Sirius red and thenumber of cells marked by α-SMA in animals treated with aliskiren, bradykinin, lisinopril and losartan were diminished when compared to control group, demonstrating reduced hepatic fibrosis after RAS blockade. These results were reinforced by ultrasonography analysis and protein expression of TGFß. These findings demonstrated the effect of RAS inhibition on hepatic fibrosis in murine schistosomiasis, with the most evident results being observed in the losartan and aliskiren treated groups. The main mechanisms underlying this process appear to involve anti-fibrogenic activity through the inhibition of collagen and TGFß synthesis.

Aliskiren: Preclinical evidence for the treatment of hyperproliferative skin disorders.

Psoriasis is a complex inflammatory and hyperproliferative skin disease. The pathogenesis and mechanisms involved are not completely understood, which makes treatment a difficult issue. Angiotensin II, the most active peptide of the renin-angiotensin system, seems to be involved in processes related to psoriasis pathogenesis, such as inflammation and cell proliferation. The aim of this study was to investigate the influence of renin inhibition on inflammation parameters and keratinocyte proliferation in a mouse model of chronic skin inflammation induced by croton oil. Aliskiren had anti-inflammatory effects by reducing levels of tumor necrosis factor-α and interleukin -6, and by inhibiting myeloperoxidase activity. Aliskiren also showed antiproliferative activity by reducing epidermal hyperplasia and proliferating cell nuclear antigen levels. Aliskiren treatment did not induce alterations in the cardiovascular system, normal skin thickness, and organ weight. These results suggest that aliskiren could be a valuable tool to be incorporated in the treatment of hyperproliferative and inflammatory skin disorders such as psoriasis.

Direct renin inhibition is not enough to prevent reactive oxygen species generation and vascular dysfunction in renovascular hypertension.

Renin-angiotensin system activation promotes oxidative stress and endothelial dysfunction. However, no previous study has examined the effects of the renin inhibitor aliskiren, either alone or combined with angiotensin II type 1 antagonists on alterations induced by two-kidney, one-clip (2K1C) hypertension. We compared the vascular effects of aliskiren (50mg/kg/day), losartan (10mg/kg/day), or both by gavage for 4 weeks in 2K1C and control rats. Treatment with losartan, aliskiren, or both exerted similar antihypertensive effects. Aliskiren lowered plasma Ang I concentrations in sham rats and in hypertensive rats treated with aliskiren or with both drugs. Aliskiren alone or combined with losartan decreased plasma angiotensin II concentrations measured by high performance liquid chromatography, whereas losartan alone had no effects. In contrast, losartan alone or combined with aliskiren abolished hypertension-induced increases in aortic angiotensin II concentrations, whereas aliskiren alone exerted no such effects. While hypertension enhanced aortic oxidative stress assessed by dihydroethidium fluorescence and by lucigenin chemiluminescence, losartan alone or combined with aliskiren, but not aliskiren alone, abolished this alteration. Hypertension impaired aortic relaxation induced by acetylcholine, and losartan alone or combined with aliskiren, but not aliskiren alone, reversed this alteration. Losartan alone or combined with aliskiren, but not aliskiren alone, increased plasma nitrite concentrations in 2K1C rats. These findings show that antihypertensive effects of aliskiren do not prevent hypertension-induced vascular oxidative stress and endothelial dysfunction. These findings contrast those found with losartan and suggest that renin inhibition is not enough to prevent hypertension-induced impaired redox biology and vascular dysfunction.

Urinary cytokine profiles according to the site of blockade of the renin-angiotensin system in nephrectomized rats.

INTRODUCTION: It is still unknown how the pharmacological inhibition of the Renin Angiotensin System (RAS) impacts the levels of inflammation and fibrosis biomarkers. OBJECTIVE: This study sought to evaluate the effect of enalapril, candesartan and aliskiren on urinary levels of cytokines in a model of chronic kidney disease (CKD). METHODS: Male Wistar rats were submitted to surgical removal of ¾ of renal parenchyma to induce CKD (¾ nephrectomy), or subjected to sham surgery (control). Animals were then randomized into five groups: Sham surgery receiving vehicle; ¾ Nephrectomy receiving vehicle; ¾ Nephrectomy receiving enalapril (10 mg/kg); ¾ Nephrectomy receiving candesartan (10 mg/kg) and ¾ Nephrectomy receiving aliskiren (10 mg/kg). Urine output, water intake, mean arterial pressure (MAP) and urinary concentrations of creatinine, urea, albuminuria, Na+, K+, interleukin (IL) -1ß, IL-6, IL-10 and transforming growth factor beta (TGF-ß) were measured. RESULTS: Nephrectomy significantly impaired renal function, increased MAP and altered the levels of all evaluated cytokines in urine. Enalapril, candesartan and aliskiren improved renal function and decreased MAP and IL-6 when compared to vehicle-treated nephrectomized group. Candesartan and aliskiren decreased IL-1ß, while only candesartan reduced TGF-ß and only aliskiren increased IL-10. CONCLUSION: Enalapril, candesartan and aliskiren presented similar effects on improving renal function and reducing MAP and urinary levels of IL-6 in rats with CKD. On the other hand, cytokine profile differed according to the treatment, suggesting that differential mechanisms were triggered in response to the site of RAS blockade.

Urinary cytokine profiles according to the site of blockade of the renin-angiotensin system in nephrectomized rats / Perfil de citocinas urinárias de acordo com o local de bloqueio do sistema renina angiotensina em ratos nefrectomizados

Abstract Introduction: It is still unknown how the pharmacological inhibition of the Renin Angiotensin System (RAS) impacts the levels of inflammation and fibrosis biomarkers. Objective: This study sought to evaluate the effect of enalapril, candesartan and aliskiren on urinary levels of cytokines in a model of chronic kidney disease (CKD). Methods: Male Wistar rats were submitted to surgical removal of ¾ of renal parenchyma to induce CKD (¾ nephrectomy), or subjected to sham surgery (control). Animals were then randomized into five groups: Sham surgery receiving vehicle; ¾ Nephrectomy receiving vehicle; ¾ Nephrectomy receiving enalapril (10 mg/kg); ¾ Nephrectomy receiving candesartan (10 mg/kg) and ¾ Nephrectomy receiving aliskiren (10 mg/kg). Urine output, water intake, mean arterial pressure (MAP) and urinary concentrations of creatinine, urea, albuminuria, Na+, K+, interleukin (IL) -1β, IL-6, IL-10 and transforming growth factor beta (TGF-β) were measured. Results: Nephrectomy significantly impaired renal function, increased MAP and altered the levels of all evaluated cytokines in urine. Enalapril, candesartan and aliskiren improved renal function and decreased MAP and IL-6 when compared to vehicle-treated nephrectomized group. Candesartan and aliskiren decreased IL-1β, while only candesartan reduced TGF-β and only aliskiren increased IL-10. Conclusion: Enalapril, candesartan and aliskiren presented similar effects on improving renal function and reducing MAP and urinary levels of IL-6 in rats with CKD. On the other hand, cytokine profile differed according to the treatment, suggesting that differential mechanisms were triggered in response to the site of RAS blockade.

Resumo Introdução: Ainda não se sabe como a inibição farmacológica do Sistema Renina Angiotensina (SRA) afeta os níveis de biomarcadores de inflamação e fibrose. Objetivo: Este estudo pretendeu avaliar o efeito de enalapril, candesartan e alisquireno sobre os níveis urinários de citocinas em um modelo de doença renal crônica (DRC). Métodos: Ratos Wistar machos foram submetidos à remoção cirúrgica de ¾ do parênquima renal para induzir DRC (nefrectomia), ou submetidos à cirurgia fictícia (controle). Animais foram então randomizados em cinco grupos: Cirurgia fictícia recebendo veículo; Nefrectomia recebendo veículo; Nefrectomia recebendo enalapril (10 mg/kg); Nefrectomia recebendo candesartan (10 mg/kg) e Nefrectomia recebendo alisquireno (10 mg/kg). Débito urinário, ingesta hídrica, pressão arterial media (PAM) e concentrações urinárias de creatinina, ureia, albumina, Na+, K+, interleucina (IL) -1β, IL-6, IL-10 e fator de transformação e crescimento beta (TGF-β) foram medidas. Resultados: A nefrectomia comprometeu significativamente a função renal, aumentou a PAM e alterou os níveis de todas as citocinas avaliadas na urina. Enalapril, candesartan e alisquireno melhoraram a função renal e diminuíram a PAM e a IL-6 quando comparado aos grupo de animais nefrectomizados tratados com veículo. Candesartan e alisquireno reduziram IL-1β, enquanto somente candesartan diminuiu o TGF-β e somente alisquireno aumentou a IL-10. Conclusão: Enalapril, candesartan e alisquireno apresentaram efeitos similares em relação à melhora da função renal e redução da PAM e dos níveis urinários de IL-6 em ratos com DRC. Por outro lado, o perfil de citocinas diferiu de acordo com o tratamento, sugerindo que diferentes mecanismos sejam desencadeados em resposta ao local de bloqueio do SRA.

A memória hiperglicêmica no rim diabético: marcas metabólicas, moleculares e epigenéticas / The hyperglycemic memory in diabetic kidney: metabolic, molecular, and epigenetic marks

A nefropatia diabética (ND) é uma das complicações microvasculares do diabetes e consiste no dano ao parênquima renal por consequência de uma série de fatores hemodinâmicos e moleculares. A ocorrência de ND e de outras complicações mesmo em indivíduos sob adequado controle glicêmico tem sido associada a um fenômeno conhecido como memória metabólica. Neste trabalho foram investigadas vias bioquímicas e moleculares persistentemente alteradas no rim de animais diabéticos tratados após um período inicial de hiperglicemia, com o propósito de entender os mecanismos envolvidos na memória metabólica. Para tanto, ratos com diabetes induzida por estreptozotocina foram mantidos hiperglicêmicos durante 4 semanas (período curto) ou 12 semanas (período longo) e posteriormente tratados com insulina isoladamente ou combinada com metformina (100mg/kg/dia) durante as 4 (período curto) ou 12 (período longo) semanas seguintes. Todos os animais tratados tiveram os seus níveis glicêmicos e função renal normalizados. Os tratamentos também foram capazes de normalizar os níveis elevados de malonaldeído no rim, bem como a excreção aumentada dos adutos de DNA 8-oxo-2'-desoxiguanosina (8-oxodG) e N2-carboxietil-2'- desoxiguanosina (CEdG) na urina observados nos animais diabéticos. Níveis aumentados de 8-oxodG foram detectados em DNA mitocondrial (mtDNA), mas não em DNA nuclear, de animais diabéticos apenas no período curto de estudo e também foram normalizados após o controle glicêmico. Nós identificamos uma via gradualmente alterada durante o curso do diabetes que permanece persistentemente alterada após o controle glicêmico tardio. Essa via compreende um declínio precoce do clearance de ácido úrico e expressão da pAMPK, seguida pelo acúmulo de fumarato, expressão aumentada de TGF-ß, expressão reduzida de PGC-1α e redução da metilação e hidroximetilação do mtDNA. A redução persistente do clearance de ácido úrico em animais diabéticos tratados pode sustentar as alterações bioquímicas renais prolongadas observadas após o controle glicêmico, e essa regulação é provavelmente mediada pela redução sustentada da expressão de pAMPK e pela indução de inflamação. Este trabalho propõe a primeira consideração do possível papel da hiperuricemia e das alterações bioquímicas subjacentes como parte da memória metabólica na nefropatia diabética

Diabetic nephropathy is one of the diabetes microvascular complications, and it consists on the damage to the renal parenchyma due to several hemodynamic and molecular factors. The occurrence of diabetic nephropathy and other complications even in those individuals under tight glycemic control has been associated to a phenomenon known as metabolic memory. Here we investigated biochemical and molecular pathways persistently altered in the kidney of diabetic animals treated after a previous period of hyperglycemia, aiming to understand underlying mechanisms in metabolic memory. Streptozotocin-induced diabetic rats were maintained hyperglycemic during 4 (short period) or 12 weeks (long period), and then they were treated with insulin alone or combined with metformin (100 mg/kg/day) for the following 4 or 12 weeks, respectively. All the treated animals had them glycemic levels and renal function normalized. The treatments were also able to control enhanced kidney malondialdehyde levels, as well as the increased urine excretion of the DNA adducts 8-oxo-2'- deoxyguanosine (8-oxodG) and N2-carboxyethyl-2'-deoxyguanosine seen in diabetic animals. Increased levels of 8-oxodG were detected in mitochondrial DNA, but not in nuclear DNA of diabetic animals in the short period, and were also recovered after glycemic control. We have identified a kidney pathway that is gradually altered during the course of diabetes and remains persistently changed after late glycemic control. This pathway comprises an early decline of uric acid clearance and pAMPK expression followed by fumarate accumulation, increased TGF-ß expression, reduced PGC-1α expression, and downregulation of methylation and hydroxymethylation of mitochondrial DNA. The sustained decrease of uric acid clearance in treated diabetes may support the prolonged kidney biochemical alterations observed after tight glycemic control, and this regulation is likely mediated by the sustained decrease of AMPK activity and the induction of inflammation. This work proposes the first consideration of the possible role of hyperuricemia and the underlying biochemical changes as part of metabolic memory in diabetic nephropathy

Metabolic Effects of Cobalt Ferrite Nanoparticles on Cervical Carcinoma Cells and Nontumorigenic Keratinocytes.

The cytotoxic response, cellular uptake, and metabolomic profile of HeLa and HaCaT cell lines treated with cobalt ferrite nanoparticles (CoFe2O4 NPs) were investigated in this study. Cell viability assays showed low cytotoxicity caused by the uptake of the nanoparticles at 2 mg/mL. However, metabolomics revealed that these nanoparticles impacted cell metabolism even when tested at a concentration that presented low cytotoxicity according to the cell viability assay. The two cell lines shared stress-related metabolic changes such as increase in alanine and creatine levels. A reduced level of fumarate was also observed in HeLa cells after treatment with the nanoparticles, and this alteration can inhibit tumorigenesis. Fumarate is considered to be an oncometabolite that can inhibit prolyl hydroxylase, and this inhibition stabilizes HIF1α, one of the master regulators of tumorigenesis that promotes tumor growth and development. In summary, this study showed that nanoparticle-treated HeLa cells demonstrated decreased concentrations of metabolites associated with cell proliferation and tumor growth. The results clearly indicated that treatment with these nanoparticles might cause a perturbation in cellular metabolism.

Efecto del aliskireno sobre la angiogénesis en modelo de membrana alantocoriónica (MAC) de pollo / Effect of aliskiren on angiogenesis in chick embryo chorioallantoic membrane (CAM) assay

La acción antiangiogénica de los inhibidores del receptor de angiotensina II (ARA II), ha sido documentada previamente, sin embargo, no ha sido descrita la relación entre angiogénesis e inhibidores directos de la renina (DRIs), los cuales participan regulando el sistema renina-angiotensina-aldosterona (SRAA). El objetivo fue demostrar el efecto antiangiogénico de aliskireno, un DRI, en membranas alantocoriónicas (MAC) de pollo, para lo cual fueron instilados aliskireno y enalapril sobre MAC en distintas concentraciones para realizar su comparación posterior. En secciones histológicas seriadas se registró el número de vasos sanguíneos presentes en 9000 µm2 bajo microscopio de luz a máximo aumento, y se realizó análisis estadístico utilizando ANOVA y el test de Tukey para demostrar posibles diferencias. Los receptores tratados con aliskireno, en ambas concentraciones utilizadas, presentaron menor densidad vascular, en comparación con los controles, siendo ésta estadísticamente significativa a mayor concentración. Aliskireno en concentraciones altas tiene un efecto antiangiogénico en un modelo experimental de MAC. Este hallazgo plantea la necesidad de estudios posteriores, dada la proyección que podría tener el uso inhibidores directos de la renina. A partir de estos resultados, se podría pensar en la factibilidad del uso de aliskireno para la modulación de la angiogénesis en diversas enfermedades crónicas no transmisibles.

Angiogenesis is the formation of new blood vessels from pre-existing ones. Antiangiogenic effect of angiotensin receptor blockers has been reported, however, the relationship between direct renin inhibitors and angiogenesis has not been well described. To assess the antiangiogenic effect of aliskiren, a direct renin inhibitor, on chick embryo chorioallantoic membrane (CAM) assay. Aliskiren and enalapril were instilled in different concentrations and compared. In serial histological sections, the number of blood vessels per 9000 µm2 area under observation through optical microscope using maximum zoom, was registered. Statistical analysis using Anova and Tukey test in order to show possible differences, was performed. Receptors treated with aliskiren presented lower vascular density, which was statistically significant when a higher concentration was administered. High concentrations of aliskiren have an antiangiogenic effect on CAM assay. This finding means further studies are needed, because of the usefulness direct renin inhibitors could have. These results, also, might enhance the possibility of using aliskiren for regulating angiogenesis in the context of non-transmissible chronic diseases.

Renin-angiotensin system blockers regulate the metabolism of isolated fat cells in vitro.

Due to the presence of the renin-angiotensin system (RAS) in tissues and its specific influence on white adipose tissue, fat cells are possible targets of pharmacological RAS blockers commonly used as anti-hypertensive drugs. In the present study, we investigated the effects of different RAS blockers on fat cell metabolism, more specifically on lipolysis, lipogenesis and oxidation of energy substrates. Isolated primary adipocytes were incubated with different RAS blockers (aliskiren, captopril and losartan) in vitro for 24 h and lipolysis, lipogenesis and glucose oxidation capacities were determined in dose-response assays to a ß-adrenergic agonist and to insulin. Although no change was found in lipolytic capacity, the RAS blockers modulated lipogenesis and glucose oxidation in a different way. While captopril decreased insulin-stimulated lipogenesis (-19% of maximal response and -60% of insulin responsiveness) due to reduced glucose derived glycerol synthesis (-19% of maximal response and 64% of insulin responsiveness), aliskiren increased insulin-stimulated glucose oxidation (+49% of maximal response and +292% of insulin responsiveness) in fat cells. Our experiments demonstrate that RAS blockers can differentially induce metabolic alterations in adipocyte metabolism, characterized by a reduction in lipogenic responsiveness or an increase in glucose oxidation. The impact of RAS blockers on adipocyte metabolism may have beneficial implications on metabolic disorders during their therapeutic use in hypertensive patients.

Aliskiren and l-arginine treatments restore depressed baroreflex sensitivity and decrease oxidative stress in renovascular hypertension rats.

Renovascular hypertension is characterized by increased angiotensin II and oxidative stress, and by endothelial dysfunction. The purpose of this study was to test whether the administration of aliskiren (ALSK) and l-arginine (l-ARG) would restore impaired baroreflex sensitivity and reduce oxidative stress in a rat renovascular hypertension model. Hypertension was induced by clipping the left renal artery, and the following five groups were created: SHAM; two-kidney, 1-clip (2K1C); 2K1C plus ALSK (ALSK); 2K1C plus l-ARG (l-ARG); and 2K1C plus ALSK+l-ARG (ALSK+l-ARG). After 21 days of treatment, only the ALSK+l-ARG group was effective in normalizing the arterial pressure (108.8±2.8 mm Hg). The l-ARG and ALSK+l-ARG groups did not show hypertrophy of the left ventricle. All the treatments restored the depressed baroreflex sensitivity to values found in the SHAM group. Acute administration of TEMPOL restored the depressed baroreflex sensitivity in the 2K1C group to values that resembled those presented by the other groups. All treatments were effective for an increase in the antioxidant pathway and reduction in the oxidative pathway. In conclusion, the treatment with ALSK or l-ARG reduced oxidative stress and restored reduced baroreflex sensitivity in renovascular hypertension. In addition, the treatments were able to normalize blood pressure and reverse left ventricular hypertrophy when used in combination.

Bovine ovarian cells have (pro)renin receptors and prorenin induces resumption of meiosis in vitro.

The discovery of a receptor that binds prorenin and renin in human endothelial and mesangial cells highlights the possible effect of renin-independent prorenin in the resumption of meiosis in oocytes that was postulated in the 1980s.This study aimed to identify the (pro)renin receptor in the ovary and to assess the effect of prorenin on meiotic resumption. The (pro)renin receptor protein was detected in bovine cumulus-oocyte complexes, theca cells, granulosa cells, and in the corpus luteum. Abundant (pro)renin receptor messenger ribonucleic acid (mRNA) was detected in the oocytes and cumulus cells, while prorenin mRNA was identified in the cumulus cells only. Prorenin at concentrations of 10(-10), 10(-9), and 10(-8)M incubated with oocytes co-cultured with follicular hemisections for 15h caused the resumption of oocyte meiosis. Aliskiren, which inhibits free renin and receptor-bound renin/prorenin, at concentrations of 10(-7), 10(-5), and 10(-3)M blocked this effect (P<0.05). To determine the involvement of angiotensin II in prorenin-induced meiosis resumption, cumulus-oocyte complexes and follicular hemisections were treated with prorenin and with angiotensin II or saralasin (angiotensin II antagonist). Prorenin induced the resumption of meiosis independently of angiotensin II. Furthermore, cumulus-oocyte complexes cultured with forskolin (200µM) and treated with prorenin and aliskiren did not exhibit a prorenin-induced resumption of meiosis (P<0.05). Only the oocytes' cyclic adenosine monophosphate levels seemed to be regulated by prorenin and/or forskolin treatment after incubation for 6h. To the best of our knowledge, this is the first study to identify the (pro)renin receptor in ovarian cells and to demonstrate the independent role of prorenin in the resumption of oocyte meiosis in cattle.

Renin-angiotensin system blockers regulate the metabolism of isolated fat cells in vitro

Due to the presence of the renin-angiotensin system (RAS) in tissues and its specific influence on white adipose tissue, fat cells are possible targets of pharmacological RAS blockers commonly used as anti-hypertensive drugs. In the present study, we investigated the effects of different RAS blockers on fat cell metabolism, more specifically on lipolysis, lipogenesis and oxidation of energy substrates. Isolated primary adipocytes were incubated with different RAS blockers (aliskiren, captopril and losartan) in vitro for 24 h and lipolysis, lipogenesis and glucose oxidation capacities were determined in dose-response assays to a β-adrenergic agonist and to insulin. Although no change was found in lipolytic capacity, the RAS blockers modulated lipogenesis and glucose oxidation in a different way. While captopril decreased insulin-stimulated lipogenesis (−19% of maximal response and −60% of insulin responsiveness) due to reduced glucose derived glycerol synthesis (−19% of maximal response and 64% of insulin responsiveness), aliskiren increased insulin-stimulated glucose oxidation (+49% of maximal response and +292% of insulin responsiveness) in fat cells. Our experiments demonstrate that RAS blockers can differentially induce metabolic alterations in adipocyte metabolism, characterized by a reduction in lipogenic responsiveness or an increase in glucose oxidation. The impact of RAS blockers on adipocyte metabolism may have beneficial implications on metabolic disorders during their therapeutic use in hypertensive patients.