Role of Angiotensin II Type 1A Receptors on Renal and Urinary Angiotensin Converting Enzyme 2 (ACE2) and Neprilysin (NEP) in the Two-Kidney One-Clip (2K1C) Model of Renovascular Hypertension

Activation of the renin angiotensin system (RAS) and increased formation of angiotensin (Ang) II contribute to the progression of chronic kidney disease (CKD). Ang II, the major biologically active peptide of RAS, acts mainly as a vasoconstrictor through binding to the Ang II type 1 receptor (AT1R), which leads to increased blood pressure, fluid retention, and aldosterone secretion. The actions of Ang II are antagonized by its conversion to the vasodilator Ang (1-7), partly generated by the action of angiotensin converting enzyme 2 (ACE2) and/or neprilysin (NEP). The metalloprotease ADAM17 has a crucial role in the shedding of renal ACE2 in diabetic mice model. The two-kidney, one clip (2K1C) Goldblatt model is an experimental approach designed to mimic renovascular hypertension. It consists of the unilateral clamping of the renal artery in one of the kidneys. The aim of this study is to test the hypotheses that: 1) renovascular hypertension and increased albuminuria in the 2K1C model is mediated by AT1AR and 2) up-regulation of renal ADAM17 increase the shedding of renal ACE2 and NEP into the urine. Wild type (WT) and AT1AR knockout (AT1 KO) mice were used to test our hypotheses. Mice were subjected to surgical procedures to implant radio-telemetry transmitters for measurement of blood pressure (BP), followed by induction of renovascular hypertension. BP at baseline was significantly lower in AT1 KO compared to WT mice, whereas in WT 2K1C, BP was significantly higher than controls (p\u3c0.05). However, 2K1C has no effect on BP in AT1 KO mice. Urinary albumin excretion significantly increased in WT 2K1C mice compared to sham -operated ones, while no change was observed in AT1 KO. In addition, a significant reduction of renal ADAM17 and NEP contents was observed in clipped kidney relative to the unclipped and sham kidneys. Western blot analysis showed a significant decrease in renal ACE2, NEP, and ADAM17 protein expression levels in the clipped kidney compared to the unclipped or sham-operated ones. Histological assessment of the kidneys in the 2K1C model revealed significant mesangial expansion and renal fibrosis. Data suggest that renovascular hypertension is mediated by AT1AR and deletion of this receptor attenuates albuminuria in the 2K1C model. In 2K1C, the downregulation of renal and urinary ACE2 and ADAM17 suggest a potential link between ADAM17 and ACE2 shedding in 2K1C mice. Decreased renal NEP in the clipped kidney of 2K1C model may thus worsen kidney injury via impairment of Ang (1-7) formation

OECD validation study to assess intra- and inter-laboratory reproducibility of the zebrafish embryo toxicity test for acute aquatic toxicity testing

The OECD validation study of the zebrafish embryo acute toxicity test (ZFET) for acute aquatic toxicity testing evaluated the ZFET reproducibility by testing 20 chemicals at 5 different concentrations in 3 independent runs in at least 3 laboratories. Stock solutions and test concentrations were analytically confirmed for 11 chemicals. Newly fertilised zebrafish eggs (20/concentration and control) were exposed for 96 h to chemicals. Four apical endpoints were recorded daily as indicators of acute lethality: coagulation of the embryo, lack of somite formation, non-detachment of the tail bud from the yolk sac and lack of heartbeat. Results (LC50 values for 48/96 h exposure) show that the ZFET is a robust method with a good intra- and inter-laboratory reproducibility (CV 30%) for some very toxic or volatile chemicals, and chemicals tested close to their limit of solubility. The ZFET is now available as OECD Test Guideline 236. Considering the high predictive capacity of the ZFET demonstrated by Belanger et al. (2013) in their retrospective analysis of acute fish toxicity and fish embryo acute toxicity data, the ZFET is ready to be considered for acute fish toxicity for regulatory purposes

Persistent Oxytetracycline Exposure Induces an Inflammatory Process That Improves Regenerative Capacity in Zebrafish Larvae

BACKGROUND: The excessive use of antibiotics in aquaculture can adversely affect not only the environment, but also fish themselves. In this regard, there is evidence that some antibiotics can activate the immune system and reduce their effectiveness. None of those studies consider in detail the adverse inflammatory effect that the antibiotic remaining in the water may cause to the fish. In this work, we use the zebrafish to analyze quantitatively the effects of persistent exposure to oxytetracycline, the most common antibiotic used in fish farming. METHODOLOGY: We developed a quantitative assay in which we exposed zebrafish larvae to oxytetracycline for a period of 24 to 96 hrs. In order to determinate if the exposure causes any inflammation reaction, we evaluated neutrophils infiltration and quantified their total number analyzing the Tg(mpx:GFP)(i114) transgenic line by fluorescence stereoscope, microscope and flow cytometry respectively. On the other hand, we characterized the process at a molecular level by analyzing several immune markers (il-1β, il-10, lysC, mpx, cyp1a) at different time points by qPCR. Finally, we evaluated the influence of the inflammation triggered by oxytetracycline on the regeneration capacity in the lateral line. CONCLUSIONS: Our results suggest that after 48 hours of exposure, the oxytetracycline triggered a widespread inflammation process that persisted until 96 hours of exposure. Interestingly, larvae that developed an inflammation process showed an improved regeneration capacity in the mechanosensory system lateral line

The behaviour and ecology of the zebrafish, Danio rerio

Author Posting. © The Authors, 2008. This is the author's version of the work. It is posted here by permission of Cambridge Philosophical Society for personal use, not for redistribution. The definitive version was published in Biological Reviews 83 (2008): 13-34, doi:10.1111/j.1469-185X.2007.00030.x.The zebrafish is an important model organism in developmental genetics, neurophysiology and biomedicine, but little is known about its natural ecology and behaviour. It is a small, shoaling cyprinid, native to the flood-plains of the Indian subcontinent, where it is found in shallow, slow-flowing waters. Zebrafish are group spawners and egg scatterers, although females are choosy with respect to sites for oviposition and males defend territories around such sites. Laboratory studies of zebrafish behaviour have encompassed shoaling, foraging, reproduction, sensory perception and learning. These studies are reviewed in relation to the suitability of the zebrafish as a model for studies on cognition and learning, development, behavioural and evolutionary ecology, and behavioural genetics

Role of Angiotensin II Type 1A Receptors on Renal and Urinary Angiotensin Converting Enzyme 2 (ACE2) and Neprilysin (NEP) in the Two-Kidney One-Clip (2K1C) Model of Renovascular Hypertension

Activation of the renin angiotensin system (RAS) and increased formation of angiotensin (Ang) II contribute to the progression of chronic kidney disease (CKD). Ang II, the major biologically active peptide of RAS, acts mainly as a vasoconstrictor through binding to the Ang II type 1 receptor (AT1R), which leads to increased blood pressure, fluid retention, and aldosterone secretion. The actions of Ang II are antagonized by its conversion to the vasodilator Ang (1-7), partly generated by the action of angiotensin converting enzyme 2 (ACE2) and/or neprilysin (NEP). The metalloprotease ADAM17 has a crucial role in the shedding of renal ACE2 in diabetic mice model. The two-kidney, one clip (2K1C) Goldblatt model is an experimental approach designed to mimic renovascular hypertension. It consists of the unilateral clamping of the renal artery in one of the kidneys. The aim of this study is to test the hypotheses that: 1) renovascular hypertension and increased albuminuria in the 2K1C model is mediated by AT1AR and 2) up-regulation of renal ADAM17 increase the shedding of renal ACE2 and NEP into the urine. Wild type (WT) and AT1AR knockout (AT1 KO) mice were used to test our hypotheses. Mice were subjected to surgical procedures to implant radio-telemetry transmitters for measurement of blood pressure (BP), followed by induction of renovascular hypertension. BP at baseline was significantly lower in AT1 KO compared to WT mice, whereas in WT 2K1C, BP was significantly higher than controls (p\u3c0.05). However, 2K1C has no effect on BP in AT1 KO mice. Urinary albumin excretion significantly increased in WT 2K1C mice compared to sham -operated ones, while no change was observed in AT1 KO. In addition, a significant reduction of renal ADAM17 and NEP contents was observed in clipped kidney relative to the unclipped and sham kidneys. Western blot analysis showed a significant decrease in renal ACE2, NEP, and ADAM17 protein expression levels in the clipped kidney compared to the unclipped or sham-operated ones. Histological assessment of the kidneys in the 2K1C model revealed significant mesangial expansion and renal fibrosis. Data suggest that renovascular hypertension is mediated by AT1AR and deletion of this receptor attenuates albuminuria in the 2K1C model. In 2K1C, the downregulation of renal and urinary ACE2 and ADAM17 suggest a potential link between ADAM17 and ACE2 shedding in 2K1C mice. Decreased renal NEP in the clipped kidney of 2K1C model may thus worsen kidney injury via impairment of Ang (1-7) formation

Corporatist control, job satisfaction and client work satisfaction: a study of human service providers

Bibliography: p. 59-6