scholarly journals PTH Modulation by Aldosterone and Angiotensin II is Blunted in Hyperaldosteronism and Rescued by Adrenalectomy

2019 ◽  
Vol 104 (9) ◽  
pp. 3726-3734 ◽  
Author(s):  
Livia Lenzini ◽  
Selene Prisco ◽  
Paul Emmanuel Vanderriele ◽  
Silvia Lerco ◽  
Francesca Torresan ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Ex Vivo ◽  
Primary Cultures ◽  
Zona Glomerulosa ◽  
Before And After ◽  
Bilateral Adrenal Hyperplasia ◽  
Aldosterone Producing Adenoma ◽  
Serum Pth

Abstract Context Accumulating evidence suggests a link between adrenocortical zona glomerulosa and parathyroid gland through mechanisms that remain unexplored. Objectives To test the hypothesis that in vivo angiotensin II blockade affects PTH secretion in patients with hypertension and that aldosterone and angiotensim II directly stimulate PTH secretion ex vivo. Design and Setting We investigated the changes of serum PTH levels induced by oral captopril (50 mg) administration in patients with primary essential hypertension (EH) and with primary aldosteronism (PA) caused by bilateral adrenal hyperplasia (BAH) or aldosterone-producing adenoma (APA), the latter before and after adrenalectomy. We also exposed primary cultures of human parathyroid cells from patients with primary hyperparathyroidism to angiotensin II (10−7 M) and/or aldosterone (10−7 M). Results Captopril lowered PTH levels (in nanograms per liter) both in patients with EH (n = 63; 25.9 ± 8.3 baseline vs 24.4 ± 8.0 postcaptopril, P < 0.0001) and in patients with APA after adrenalectomy (n = 27; 26.3 ± 11.6 vs 24.0 ± 9.7 P = 0.021). However, it was ineffective in patients with full-blown PA caused by APA and BAH. In primary culture of human parathyroid cells, both aldosterone (P < 0.001) and angiotensin II (P = 0.002) markedly increased PTH secretion from baseline, by acting through mineralocorticoid receptor and angiotensin type 1 receptor, as these effects were abolished by canrenone and irbesartan, respectively. Conclusion These results collectively suggest an implication of the renin-angiotensin-aldosterone system in PTH regulation in humans, at least in PTH-secreting cells obtained from parathyroid tumors. Moreover, they further support the concept that mild hyperparathyroidism is a feature of human PA that is correctable with adrenalectomy.

scholarly journals Angiotensin II Type 1 Receptor Autoantibodies in Primary Aldosteronism

2020 ◽  
Vol 52 (06) ◽  
pp. 379-385
Author(s):  
Lucie S. Meyer ◽  
Siyuan Gong ◽  
Martin Reincke ◽  
Tracy Ann Williams
Keyword(s):  
Angiotensin Ii ◽  
Primary Aldosteronism ◽  
Functional Role ◽  
Adrenal Hyperplasia ◽  
Endocrine Hypertension ◽  
Bilateral Adrenal Hyperplasia ◽  
Aldosterone Producing Adenoma ◽  
Agonistic Autoantibodies

AbstractPrimary aldosteronism (PA) is the most common form of endocrine hypertension. Agonistic autoantibodies against the angiotensin II type 1 receptor (AT1R-Abs) have been described in transplantation medicine and women with pre-eclampsia and more recently in patients with PA. Any functional role of AT1R-Abs in either of the two main subtypes of PA (aldosterone-producing adenoma or bilateral adrenal hyperplasia) requires clarification. In this review, we discuss the studies performed to date on AT1R-Abs in PA.

scholarly journals Early Spatial and Temporal Events of Human T-Lymphotropic Virus Type 1 Spread following Blood-Borne Transmission in a Rabbit Model of Infection

2010 ◽  
Vol 84 (10) ◽  
pp. 5124-5130 ◽  
Author(s):  
Rashade A. H. Haynes ◽  
Bevin Zimmerman ◽  
Laurie Millward ◽  
Evan Ware ◽  
Christopher Premanandan ◽  
...  
Keyword(s):  
Virus Type ◽  
Ex Vivo ◽  
Rabbit Model ◽  
Virus Detection ◽  
Mononuclear Leukocytes ◽  
T Lymphotropic Virus ◽  
Viral Spread ◽  
Temporal Events

ABSTRACT Human T-lymphotropic virus type 1 (HTLV-1) infection causes adult T-cell leukemia/lymphoma (ATL) and is associated with a variety of lymphocyte-mediated disorders. HTLV-1 transmission occurs by transmission of infected cells via breast-feeding by infected mothers, sexual intercourse, and contaminated blood products. The route of exposure and early virus replication events are believed to be key determinants of virus-associated spread, antiviral immune responses, and ultimately disease outcomes. The lack of knowledge of early events of HTLV-1 spread following blood-borne transmission of the virus in vivo hinders a more complete understanding of the immunopathogenesis of HTLV-1 infections. Herein, we have used an established animal model of HTLV-1 infection to study early spatial and temporal events of the viral infection. Twelve-week-old rabbits were injected intravenously with cell-associated HTLV-1 (ACH-transformed R49). Blood and tissues were collected at defined intervals throughout the study to test the early spread of the infection. Antibody and hematologic responses were monitored throughout the infection. HTLV-1 intracellular Tax and soluble p19 matrix were tested from ex vivo cultured lymphocytes. Proviral copy numbers were measured by real-time PCR from blood and tissue mononuclear leukocytes. Our data indicate that intravenous infection with cell-associated HTLV-1 targets lymphocytes located in both primary lymphoid and gut-associated lymphoid compartments. A transient lymphocytosis that correlated with peak virus detection parameters was observed by 1 week postinfection before returning to baseline levels. Our data support emerging evidence that HTLV-1 promotes lymphocyte proliferation preceding early viral spread in lymphoid compartments to establish and maintain persistent infection.

Effects of angiotensin II and ACTH on normal and tumourous human adrenocortical cells

1983 ◽  
Vol 104 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Wolfgang Belmega ◽  
Wolfgang Oelkers ◽  
Lutz Belkien ◽  
Monika Shirpai ◽  
Ulrich Fiedler ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Renin Angiotensin System ◽  
Zona Glomerulosa ◽  
Zona Fasciculata ◽  
Adrenocortical Adenoma ◽  
Response Curves ◽  
Adrenocortical Cells ◽  
Normal Cells ◽  
Fold Stimulation

Abstract. Isolated adrenocortical cells from 6 patients with a 'normal' zona fasciculata, 4 patients with a 'normal' zona glomerulosa, and tumour cells from 1 adrenocortical adenoma and 1 carcinoma were incubated with and without increasing concentrations of ACTH 1–24 (10−13 m to 10−9 m) or Asp1-Ile5-angiotensin II (10−11 m to 10−7 m). In 4/5 'normal' cases, cortisol was clearly stimulated by 10−13 m ACTH. The maximum of the dose-response curve (5-fold stimulation) was reached at 10−10 m ACTH. Angiotensin II (All) started to stimulate 'normal' cells at 10−11 m with a maximum (2-fold stimulation) at 10−9 m. Aldosterone production by 'normal' cells was less markedly stimulated by ACTH and All, although the threshold doses for both peptides were similar to those of the cortisol response curves. The cells of the adrenocortical adenoma from a patient with Cushing's syndrome produced large amounts of cortisol and small amounts of aldosterone, both steroids being clearly stimulated by ACTH and AII. The adrenocortical carcinoma cells produced small amounts of cortisol and no aldosterone. Cortisol production responded to ACTH, but not to AII. The results suggest that an activated renin-angiotensin system may stimulate the zona fasciculata, since 10−11 m All (= 10 pg AII/ml) is a normal plasma All concentration on an unrestricted diet. Clinical evidence supporting this thesis is reviewed. However, cortisol production itself will rarely be increased by All in vivo, since a downregulation of ACTH would occur.

Internalisation of the type I angiotensin II receptor (ATI) and angiotensin II function in the rat adrenal zona glomerulosa cell.

1994 ◽  
Vol 141 (2) ◽  
pp. R5-R9 ◽  
Author(s):  
G. P. Vinson ◽  
M. M. Ho. ◽  
J.R. Puddefoot ◽  
R. Teja ◽  
S. Barker
Keyword(s):  
Monoclonal Antibody ◽  
Plasma Membrane ◽  
Angiotensin Ii ◽  
Zona Glomerulosa ◽  
Type I ◽  
Specific Monoclonal Antibody ◽  
Angiotensin Ii Receptor ◽  
Cellular Localisation ◽  
Glomerulosa Cells

ABSTRACT Little is known about the cellular localisation of the angiotensin II (AII) type 1 receptor (ATI) in the rat adrenal glomerulosa cell, but some studies have suggested that receptor internalisation and recycling may occur. Using a specific monoclonal antibody (6313/G2) to the first extracellular domain, we show here that most of the receptor is internalised in the unstimulated cell. When viable glomerulosa cells are incubated with 6313/G2, the receptor is transiently concentrated on the cell surface, and aldosterone output is stimulated. This stimulated output is enhanced by neither threshold nor maximal stimulatory concentrations of All amide, although the antibody does not inhibit All binding to the receptor. Conversely, the stimulatory actions of the antibody and those of ACTH are additive. The data suggest that recycling to the plasma membrane is constitutive, or regulated by unknown factors. Retention of the ATI receptor in the membrane is alone enough to allow sufficient G protein interaction to generate maximal stimulatory events.

Abstract 56: Candesartan And Valsartan, Contrary To Irbesartan, Are Potent Biased Antagonists Of Adrenal (beta)arrestin-dependent, Angiotensin II Type 1 Receptor-induced Aldosterone Production And Improve Cardiac Function Post-myocardial Infarction

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Anastasios Lymperopoulos ◽  
Karlee Walklett ◽  
Samalia Dabul ◽  
Ashley Siryk ◽  
Emmanuel Sturchler ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Angiotensin Ii ◽  
Cardiac Function ◽  
G Protein ◽  
Plasma Aldosterone ◽  
Post Myocardial Infarction ◽  
Aldosterone Production

Introduction: The scaffolding protein βarrestin1 (βarr1) by the angiotensin II (AngII) type 1 receptor (AT 1 R) mediates AngII-induced aldosterone production in vitro and physiologically in vivo, thereby exacerbating heart failure (HF) progression post-myocardial infarction (MI). Herein, we sought to investigate the relative potency of various AT 1 R antagonist drugs (sartans) at inhibiting βarr vs. G protein activation and hence aldosterone production in vitro and in vivo. We also investigated the alterations in plasma aldosterone levels conferred by these agents and their impact on cardiac function of post-MI rats. Methods: For the in vitro tests, transfected CHO and adrenocortical H295R cells were used. For in vivo studies, post-MI rats overexpressing βarr1 in their adrenals received 7-day-long treatments with the drugs of interest. Results: Among the sartans tested, candesartan and valsartan were the most potent βarr activation and βarr-mediated aldosterone production inhibitors in vitro, as well as the most “biased” antagonists towards βarr vs. G-protein inhibition. Conversely, losartan and irbesartan were the least potent βarr inhibitors and the least “biased” antagonists towards βarr inhibition. These in vitro findings were corroborated in vivo, since candesartan and valsartan, contrary to irbesartan, caused significant plasma aldosterone reductions in post-MI rats. Accordingly, cardiac ejection fraction (EF) and contractility were significantly augmented in candesartan- and valsartan-treated rats (EF: 41.1±1% and 40±1% respectively, vs. 35±0.3% for saline-treated), but further deteriorated in irbesartan-treated post-MI rats (EF: 32±1%, n=7 rats/group). Conclusions: These findings provide important insights that might aid pharmacotherapeutic decisions (i.e. individual agent selections) involving this commonly prescribed cardiovascular drug class (sartans).

scholarly journals Synthesis and Evaluation of [18F]FEtLos and [18F]AMBF3Los as Novel 18F-Labelled Losartan Derivatives for Molecular Imaging of Angiotensin II Type 1 Receptors

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1872
Author(s):  
Martha Sahylí Ortega Pijeira ◽  
Paulo Sérgio Gonçalves Nunes ◽  
Sofia Nascimento dos Santos ◽  
Zhengxing Zhang ◽  
Arian Pérez Nario ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Binding Affinity ◽  
Renin Angiotensin System ◽  
Prosthetic Group ◽  
Positron Emission ◽  
One Step ◽  
Group 2

Losartan is widely used in clinics to treat cardiovascular related diseases by selectively blocking the angiotensin II type 1 receptors (AT1Rs), which regulate the renin-angiotensin system (RAS). Therefore, monitoring the physiological and pathological biodistribution of AT1R using positron emission tomography (PET) might be a valuable tool to assess the functionality of RAS. Herein, we describe the synthesis and characterization of two novel losartan derivatives PET tracers, [18F]fluoroethyl-losartan ([18F]FEtLos) and [18F]ammoniomethyltrifluoroborate-losartan ([18F]AMBF3Los). [18F]FEtLos was radiolabeled by 18F-fluoroalkylation of losartan potassium using the prosthetic group 2-[18F]fluoroethyl tosylate; whereas [18F]AMBF3Los was prepared following an one-step 18F-19F isotopic exchange reaction, in an overall yield of 2.7 ± 0.9% and 11 ± 4%, respectively, with high radiochemical purity (>95%). Binding competition assays in AT1R-expressing membranes showed that AMBF3Los presented an almost equivalent binding affinity (Ki 7.9 nM) as the cold reference Losartan (Ki 1.5 nM), unlike FEtLos (Ki 2000 nM). In vitro and in vivo assays showed that [18F]AMBF3Los displayed a good binding affinity for AT1R-overexpressing CHO cells and was able to specifically bind to renal AT1R. Hence, our data demonstrate [18F]AMBF3Los as a new tool for PET imaging of AT1R with possible applications for the diagnosis of cardiovascular, inflammatory and cancer diseases.

scholarly journals Brain Tissue Conductivity Measurements with MR-Electrical Properties Tomography: An In Vivo Study

2020 ◽  
Author(s):  
Stefano Mandija ◽  
Petar I. Petrov ◽  
Jord J. T. Vink ◽  
Sebastian F. W. Neggers ◽  
Cornelis A. T. van den Berg
Keyword(s):  
Electrical Properties ◽  
Healthy Subjects ◽  
Ex Vivo ◽  
Simulated Data ◽  
Ground Truth ◽  
In Vivo Study ◽  
Conductivity Measurements ◽  
Tissue Conductivity ◽  
Before And After

AbstractFirst in vivo brain conductivity reconstructions using Helmholtz MR-Electrical Properties Tomography (MR-EPT) have been published. However, a large variation in the reconstructed conductivity values is reported and these values differ from ex vivo conductivity measurements. Given this lack of agreement, we performed an in vivo study on eight healthy subjects to provide reference in vivo brain conductivity values. MR-EPT reconstructions were performed at 3 T for eight healthy subjects. Mean conductivity and standard deviation values in the white matter, gray matter and cerebrospinal fluid (σWM, σGM, and σCSF) were computed for each subject before and after erosion of regions at tissue boundaries, which are affected by typical MR-EPT reconstruction errors. The obtained values were compared to the reported ex vivo literature values. To benchmark the accuracy of in vivo conductivity reconstructions, the same pipeline was applied to simulated data, which allow knowledge of ground truth conductivity. Provided sufficient boundary erosion, the in vivo σWM and σGM values obtained in this study agree for the first time with literature values measured ex vivo. This could not be verified for the CSF due to its limited spatial extension. Conductivity reconstructions from simulated data verified conductivity reconstructions from in vivo data and demonstrated the importance of discarding voxels at tissue boundaries. The presented σWM and σGM values can therefore be used for comparison in future studies employing different MR-EPT techniques.

Plasticity of endothelial cells: rapid dedifferentiation of freshly isolated high endothelial venule endothelial cells outside the lymphoid tissue microenvironment

Blood ◽  
2004 ◽  
Vol 103 (11) ◽  
pp. 4164-4172 ◽  
Author(s):  
Delphine-Armelle Lacorre ◽  
Espen S. Baekkevold ◽  
Ignacio Garrido ◽  
Per Brandtzaeg ◽  
Guttorm Haraldsen ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Lymphoid Tissue ◽  
Ex Vivo ◽  
Primary Cultures ◽  
High Endothelial Venule ◽  
Tissue Specific ◽  
Tissue Microenvironment ◽  
Cell Phenotypes

Abstract Endothelial cells display remarkable heterogeneity in different organs and vascular beds. Although many studies suggest that tissues “speak” to endothelial cells, endothelial cell diversity remains poorly characterized at the molecular level. Here, we describe a novel strategy to characterize tissue-specific endothelial cell phenotypes and to identify endothelial cell genes that are under the control of the local microenvironment. By comparing post-capillary high endothelial venule endothelial cells (HEVECs), freshly isolated from human tonsils without any cell culture step, with HEVECs cultured for 2 days, we found that HEVECs rapidly lost their specialized characteristics when isolated from the lymphoid tissue microenvironment. Striking changes occurred as early as after 48 hours, with complete loss of the postcapillary venule–specific Duffy antigen receptor for chemokines (DARCs) and the HEV-specific fucosyltransferase Fuc-TVII. DNA microarray analysis identified several other candidate HEV genes that were rapidly down-regulated ex vivo, including type XV collagen, which we characterized as a novel, abundant HEV transcript in situ. Together, our results demonstrate that blood vessel type–specific and tissue-specific characteristics of endothelial cells are under the control of their microenvironment. Therefore, even short-term primary cultures of human endothelial cells may not adequately mimic the differentiated endothelial cell phenotypes existing in vivo.

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