Effect of aldosterone on the amplification of oncolytic vaccinia virus in human cancer lines / 대한간학회지

BACKGROUND/AIMS: JX-594 is an oncolytic virus derived from the Wyeth vaccinia strain that causes replication-dependent cytolysis and antitumor immunity. Starting with a cross-examination of clinical-trial samples from advanced hepatocellular carcinoma patients having high levels of aldosterone and virus amplification in JX-594 treatment, we investigated the association between virus amplification and aldosterone in human cancer cell lines. METHODS: Cell proliferation was determined by a cell-counting-kit-based colorimetric assay, and vaccinia virus quantitation was performed by quantitative polymerase chain reaction (qPCR) and a viral plaque assay. Also, the intracellular pH was measured using a pH-sensitive dye. RESULTS: Simultaneous treatment with JX-594 and aldosterone significantly increased viral replication in A2780, PC-3, and HepG2 cell lines, but not in U2OS cell lines. Furthermore, the aldosterone treatment time altered the JX-594 replication according to the cell line. The JX-594 replication peaked after 48 and 24 hours of treatment in PC-3 and HepG2 cells, respectively. qPCR showed that JX-594 entry across the plasma membrane was increased, however, the changes are not significant by the treatment. This was inhibited by treatment with spironolactone (an aldosterone-receptor inhibitor). JX-594 entry was significantly decreased by treatment with EIPA [5-(N-ethyl-N-isopropyl)amiloride; a Na+/H+-exchange inhibitor], but aldosterone significantly restored JX-594 entry even in the presence of EIPA. Intracellular alkalization was observed after aldosterone treatment but was acidified by EIPA treatment. CONCLUSIONS: Aldosterone stimulates JX-594 amplification via increased virus entry by affecting the H+ gradient.

Effect of felodipine on myocardial and renal injury induced by aldosterone-high salt hypertension in uninephrectomized rats

It has been recently shown that calcium channel blockers might have a protective effect on cardiac fibrogenesis induced by aldosterone. The objective of this study was to evaluate the protective effect of felodipine, a dihydropyridine calcium channel blocker, against heart and kidney damage caused by aldosterone-high sodium intake in uninephrectomized rats. Wistar rats were divided into three groups: CNEP (uninephrectomized + 1 percent NaCl in the drinking water, N = 9); ALDO (same as CNEP group plus continuous infusion of 0.75 µg/h aldosterone, N = 12); ALDOF (same as ALDO group plus 30 mg·kg-1·day-1 felodipine in the drinking water, N = 10). All results were compared with those of age-matched, untreated rats (CTL group, N = 10). After 6 weeks, tail cuff blood pressure was recorded and the rats were killed for histological analysis. Blood pressure (mmHg) was significantly elevated (P < 0.05) in ALDO (180 ± 20) and ALDOF (168 ± 13) compared to CTL (123 ± 12) and CNEP (134 ± 13). Heart damage (lesion scores - median and interquartile range) was 7.0 (5.5-8.0) in ALDO and was fully prevented in ALDOF (1.5; 1.0-2.0). Also, left ventricular collagen volume fraction ( percent) in ALDOF (2.9 ± 0.5) was similar to CTL (2.9 ± 0.5) and CNEP (3.4 ± 0.4) and decreased compared to ALDO (5.1 ± 1.6). Felodipine partially prevented kidney injury since the damage score for ALDOF (2.0; 2.0-3.0) was significantly decreased compared to ALDO (7.5; 4.0-10.5), although higher than CTL (null score). Felodipine has a protective effect on the myocardium and kidney as evidenced by decreased perivascular inflammation, myocardial necrosis and fibrosis.

Aldosterone-induced TGF-beta1 Expression is Regulated by Mitogen-Activated Protein Kinases and Activator Protein-1 in Mesangial Cells

Aldosterone has been shown to stimulate renal TGF-beta1 expression. However, the mechanisms for aldosterone-induced TGF-beta1 expression have not been clearly determined in mesangial cells. We examined the role of extracellular-signal regulated kinase 1 and 2 (ERK1/2), c-Jun N-terminal kinase (JNK) and activator protein- 1 (AP-1) in the aldosterone-induced TGF-beta1 expression in rat mesangial cells. TGF-beta1 protein in the conditioned medium released from rat mesangial cells was measured by sandwich ELISA, TGF-beta1 mRNA expression was analyzed by Northern blotting, AP-1 DNA binding activity was measured by EMSA and the ERK1/2, JNK activity was analyzed by western blotting. Aldosterone significantly stimulated TGF-beta1 protein production and TGF-beta1 mRNA expression in mesangial cells in a dose-dependent manner. Aldosterone significantly increased AP-1 DNA binding activity in mesangial cells. Pre-treatment of cells with AP-1 inhibitor, curcumin, blocked aldosterone-induced AP-1 DNA binding activity as well as aldosterone-induced TGF-beta1 production. Aldosterone increased phosphorylation of ERK1/2 and JNK in mesangial cells. Pre-treatment of cells with ERK1/2 inhibitor, PD98059, or JNK inhibitor, SP600125 significantly inhibited aldosterone-induced ERK1/2 and JNK activity and subsequently TGF-beta1 production, respectively. We conclude that aldosteroneinduced TGF-beta1 expression in mesangial cells is regulated by the ERK1/ 2, JNK and AP-1 intracellular signaling pathways.

Aldosterone Upregulates Connective Tissue Growth Factor Gene Expression via p38 MAPK Pathway and Mineralocorticoid Receptor in Ventricular Myocytes

The effect of aldosterone on connective tissue growth factor (CTGF) was examined in rat embryonic ventricular myocytes. Upon aldosterone treatment, CTGF expression was significantly increased in a dose and time-dependent manner. To explore the molecular mechanism for this upregulation, we examined the role of mineralocorticoid receptor. Pre-treatment of an antagonist (spironolactone) at 5-fold excess of aldosterone blocked the CTGF induction by aldosterone, suggesting that the upregulation was mediated by mineralocorticoid receptor. Aldosterone treatment resulted in activation of ERK1/2, p38 MAPK, and JNK pathways with a more transient pat-tern in p38 MAPK. Blocking studies using pre-treatment of the inhibitor of each path-way revealed that p38 MAPK cascade may be important for aldosterone-mediated CTGF upregulation as evidenced by the blocking of CTGF induction by SB203580 (p38 MAPK inhibitor), but not by PD098059 (ERK1/2 inhibitor) and JNK inhibitor I. Interestingly, JNK inhibitor I and PD098059 decreased the basal level of CTGF expression. On the other hand, pre-treatment of spironolactone abrogated the p38 MAPK activation, indicating that mineralocorticoid receptor mechanism is linked to p38 MAPK pathway. Taken together, our findings suggest that aldosterone induces CTGF expression via both p38 MAPK cascade and mineralocorticoid receptor and that cross-talk exists between the two pathways.

Efecto de la deshidratación sobre la aldosterona durante una actividad física intensa y de larga duración

Objetivo: Establecer los efectos de la deshidratación sobre la concentración plasmática de aldosterona y sus efectos renales durante una actividad física intensa y de larga duración, en nueve corredores de fondo. Material y métodos: Después de diez minutos de calentamiento, en banda rodante con una pendiente de 1 por ciento y 55 por ciento de la capacidad física de trabajo máxima (PWCmax), siguieron 90 minutos de carrera, al 80 por ciento; fianlente, 90 minutos de recuperación. No se hizo reposición hídrica durante DH (deshidratado); durante RH (rehidratado) se repuso 51 por ciento del peso corporal perdido en DH. Resultados: en DH hubo pérdida de peso corporal y reducción porcentual del volumen plasmático (porcentaje VP). Se observó hiperosmolaridad, hipernatremia, hipercaliemia e hiperaldosteronemia. El índice orina/plasma del sodio disminuyó al final del ejercicio y el del potasio aumentó al final de la recuperación. El índice urinario sodio/potasio disminuyó durante el procedimiento. En RH la pérdida de peso corporal fue menor, pero la reducción porcentaje VP fue similar; con la reposición parcial de las pérdidas hídricas se evitaron la hipersomolaridad y la hipernatremia, pero no la hipercaliemia durante el ejercicio, ni la hiperaldosteronemia durante todo el procedimiento. Los índices orina/plasma para el sodio y el potasio no variaron significativamente. El índice urinario sodio/plasma mostró un comportamiento similar al observado en DH. Conclusiones: La concentración plasmática de aldosterona incrementó proporcionalmente a la duración del ejercicio e independientemente del grado de hidratación; se presentó una respuesta reanl disgregada: inicialmente, un incremento en la reabsorción de sodio y posteriormente, un incremento en la secreción del potasio, en respuesta, posiblemente, a la carga ácida impuesta por acidosis metabólica.

Changes in the electrophysiological parameters of the posterior intestine of Anguilla anguilla (Pisces) induced by oxytocin, urotensin II and aldosterone

In view of the importance of the intestine in the osmoregulation of freshwater fishes, we determined the effects of oxytocin, urotensin II (UII), and aldosterone added to the serosal side of the isolated posterior intestine of the freshwater-adapted teleost Anguilla anguilla on electrophysiological parameters. Oxytocin decreased the short-ciruit current (SCC) and transepithelial potential difference (TPD) at a centrations of 1 and 10 mU/ml (to 50 per cent and 42 per cent of control values, respectively), but did not alter these parameters at a concentration of 0.1 mU/ml. UII reduced SCC and TPD at concentrations of 10 nM, 50nM and 100 nM (to 85 per cent of control values), but increased these parameters at the concentration of 500 nM (to 115 per cent of control values). Aldosterone did not alter SCC or TPD at the concentrations tested (10 nM and 100 nM). Oxytocin may open Na+ channels in the apical membrane, allowing the flow of Na+ to the serosa, reduced SCC and TPD. Should this hypothesis be correct, oxytocin would be important for freshwater adaptation, since it would increase absorption. The reduction of SCC and TPD in the posterior intestine A. anguilla induced by UII is evidence that this neurohormone is also important for freshwater adaptation in teleosts. Aldosterone did not show this effect probaly due to the lack of receptors in this organ.

Effects of chronic treatments with adrenal steroids on acid-base homeostasis in the rat

Urinary parameters related to acid base homeostasis were studied in adrenalectomized rats (ADX) as well as in ADX treated with physiological doses of corticosterone (B), aldosterone (aldo) or 18-Hydroxycorticosterone (l8HOB) during 1,3 or 5 days, under basal conditions and after gravage with 200 mM HCI. The results showed: a) a persistent effect of B and l8HOB increasing titratable acidity principally in response to acidosis; b) an increased phosphate elimination in acidotic B treated ADX on the first day, and in 18 HOB treated ADX on days 3 and 5; c) pronounced increases in blood pH and blood bicarbonate levels provoked by the three steroids on day 1; d) increments of ammonium elimination in response to acidosis by aldo treatmets on the first day, while B and l8HOB increase ammonium elimination under almost all conditions during the whole experiment; e) the effects of B and 18 HOB would be independent of an increase in sodium retention as well as glomerular filtration rate.

Atropine enhancement of aldosterone induced renal sodium reabsorption in dogs

El objetivo del presente trabajo fue investigar el efecto de la atropina sobre la membrana de los túbulos renales, como hemos sugerido en un trabajo previo. Se anestesiaron perros mestizos a los que se les infundió una solución de ClNa isotónica por vía endovenosa. Se cateterizaron ambos uréteres y se recogieron muestras de orina en períodos de diez minutos. Diferentes grupos de perros recibieron una dosis única de aldosterona ev (2 y 4 ug/kg de peso corporal); atropina (1 ug/kg de peso corporal); atropina previa a la dosis menor de aldosterona y solución salina en volúmenes de 1 ml. La administración de atropina previa a la dosis menor de aldosterona aumentó el efecto antinatriurético de la hormona y, además, produjo una anticipación en la aparición del efecto. Los resultados obtenidos parecen compatibles con cambios de la permeabilidad o de la capacidad de transporte de las membranas tubulares inducidos por atropina

Effect of corticosteroids on electrolyte transport in the descending colon of the rat

El efecto de corticosteroides sobre el movimiento de electrolitos fue estudiado en un modelo de saco evertido del colón distal de rata. La corticosterona tiene un significativo efecto estimulador, dependiente de la dosis, sobre la transferencia de sodio y líquido. Con la baja dosis de 10-9M la corticosterona aumentó la absorción de sodio en 29.4 micronEq g-1 h-1, valor que fue estadisticamente mayor que el efecto de dexametasona 10-9M. Con la alta concentración de 10-7M el efecto de corticosterona sobre el movimiento de sodio fue dos veces el de aldosterona o dexametasona en concentraciones equimolares. En cambio, el efecto de corticosterona sobre el movimiento de potasio fue bifásico: a baja concentración (10-9M) se encontró una significativa secreción neta, mientras que con corticosterona 10-7M se observó absorción de potasio. La dexametasona aumentó significativamente la secreción neta de potasio, mientras que el efecto de aldosterona sobre el movimiento de potasio no fue significativamente diferente de los controles. Estos datos sugieron que el glucocorticoide nativo, corticosterona, ejerce un control regulatorio de la función de los electrolitos y líquidos del colon

study of antidiuretic hormone and aldosterone in children with grand epilepsy as influenced by drug therapy

This study was conducted on thirty children with grand mal epilepsy attending the paediatric neurology clinic of the Alexandria University Hospital for Sick Children, all of them were new untreated cases. The diagnosis was built up on both clinical and electroencephalographic grounds. Children were divided into two major groups; the first group received CBZ as the sole drug of therapy, the second group received sodium vaiproate as the sole antiepileptic drug. Serum and urinary sodium, potassium, osmolality, serum aldosterone and plasma ADH were determined for all the cases before initiation of therapy and three months later. Twenty normal age matched children without personal or family history of epilepsy or febrile convulsions were included in this study as controls and subjected to the same laboratory investigations