Vasoconstrictor and Pressor Effects of Des-Aspartate-Angiotensin I in Rat.

This study investigated the vasoactive effects of des-aspartate-angiotensin-I (DAA-I) in male Wistar rats on whole body vascular bed, isolated perfused kidneys, and aortic rings. Dose-response curves to DAA-I were compared with those to angiotensin II (Ang II). The Ang II-type-1 (AT1) receptor blocker, losartan, was used to evaluate the role of AT1 receptors in the responses to DAA-I. Studies were also conducted of the responsiveness in aortic rings after endothelium removal, nitric oxide synthase inhibition, or AT2 receptor blockade. DAA-I induced a dose-related systemic pressor response that was shifted to the right compared with Ang II. Losartan markedly attenuated the responsiveness to DAA-I. DAA-I showed a similar pattern in renal vasculature and aortic rings. In aortic rings, removal of endothelium and nitric oxide inhibition increased the sensitivity and maximal response to DAA-I and Ang II. AT2 receptor blockade did not significantly affect the responsiveness to DAA-I. According to these findings, DAA-I increases the systemic blood pressure and vascular tone in conductance and resistance vessels via AT1 receptor activation. This vasoconstrictor effect of DAA-I participates in the homeostatic control of arterial pressure, which can also contribute to the pathogenesis of hypertension. DAA-I may therefore be a potential therapeutic target in cardiovascular disease.

Efecto de la cardioversión eléctrica programada de fibrilación auricular sobre la función renal / Effect of programmed electrical cardioversion of atrial fibrillation on renal function

Resumen Introducción: Estudios previos han relacionado la presencia de fibrilación auricular (FA) con una tasa de filtrado glomerular estimada (TFGe) reducida. Objetivo: comparar la evolución de la TFGe en pacientes con FA persistente tras cardioversión eléctrica (CVE) programada en función de la existencia o no de recurrencias, así como la evolución de varios biomarcadores. Materiales y métodos: Cohorte prospectiva de pacientes con FA persistente remitidos a nuestro centro para CVE programada con seguimiento de un año. La TFGe se obtuvo mediante la fórmula CKD-EPI en el momento basal y a los 3 y 12 meses. Se midieron biomarcadores antes de la CVE y a los 12 meses. Resultados: Se incluyeron 92 pacientes con FA persistente, edad media de 64 ± 11 años. Al año de seguimiento y en el total de pacientes, la TFGe se redujo de 86,5 [74,6-97,6 a 84,5 [71,7-95,1 ml/min/1,73 m2 (p = 0,002) y la creatinina aumentó de 0,80 [0,72-0,94] mg/dl a 0,83 [0,74-0,97] mg/dl (p = 0,005). La TFGe se redujo al final del seguimiento, sin diferencia estadísticamente significativa entre los pacientes que presentaron recurrencia a los 12 meses y los que no. Las cifras de BNP y corina mejoraron a los 12 meses, mientras que las de galectina-3 no cambiaron, sin relación con la TFGe. Conclusiones: En los pacientes con FA persistente tratados con CVE programada se observó un empeoramiento de la TFGe al año de seguimiento. Los niveles de BNP y corina mejoraron al año de seguimiento. No hubo diferencias en los niveles de galectina-3.

Abstract Introduction: Previous studies have linked the presence of atrial fibrillation (AF) with a reduced estimated glomerular filtration rate (eGFR). Objective: to compare the evolution of eGFR in patients with persistent AF after elective electrical cardioversion (ECV) based on the existence or not of recurrences, as well as the evolution of various biomarkers. Materials and methods: Prospective cohort of patients with persistent AF referred to our center for elective EVC with a 1-year follow-up. The eGFR was obtained using the CKD-EPI formula at baseline and at 3 and 12 months. Biomarkers were measured before ECV and at 12 months. Results: 92 patients with persistent AF were included, mean age 64 ± 11 years. At one year of follow-up and in all patients, the eGFR decreased from 86.5 [74.6-97.6 to 84.5 [71.7-95.1 ml/min/1.73 m2 (p = 0.002) and creatinine increased from 0.80 [0.72-0.94] mg/dl to 0.83 [0.74-0.97] mg/dl (p = 0.005). The eGFR was reduced at the end of the follow-up, with no statistically significant difference between the patients who had recurrence at 12 months and those who did not. BNP and corin levels improved at 12 months, while galectin-3 did not change, unrelated to eGFR. Conclusions: In patients with persistent AF treated with elective ECV, a worsening of eGFR was observed at one year of follow-up. BNP and corin levels improve at one year of follow-up, there were no differences in galectin-3 levels.

The Long-Term Study of Urinary Biomarkers of Renal Injury in Spontaneously Hypertensive Rats.

BACKGROUND: The age-related increase in blood pressure in spontaneously hypertensive rats (SHRs) is associated to cardiac hypertrophy, heart failure, and renal injury. Here, we investigated for the first time the urinary enzymatic activities of glutamil aminopeptidase (GluAp), alanyl aminopeptidase (AlaAp), dipeptidyl peptidase-4 (DPP4), and Klotho urinary levels, proteins that are strongly expressed in the kidney, as early biomarkers of renal injury in SHRs. METHODS: Male SHR and Wistar Kyoto (WKY) rats were studied from 2 to 8 months old. Systolic blood pressure (SBP), the heart rate (HR), metabolic variables, and urinary markers were measured monthly. At the end of the study, a histopathological evaluation of the kidney was performed. RESULTS: Kidneys of SHR did not develop signs of relevant histopathological changes, but showed increased glomerular area and cellularity. Plasma creatinine was decreased, and creatinine clearance was augmented in SHR at the end of the study. Urinary excretion of Klotho was higher in SHR at 5 and 8 months old, whereas plasma Klotho levels were similar to WKY. GluAp, AlaAp, and DPP4 urinary activities were increased in SHR throughout the time-course study. A positive correlation between glomerular area and cellularity with creatinine clearance was observed. Urinary GluAp, AlaAp, DPP4, and Klotho showed positive correlations with SBP. CONCLUSIONS: GluAp, AlaAp, DPP4, and Klotho in the urine are useful tools for the evaluation of renal damage at early stages, before the whole histopathological and biochemical manifestations of renal disease are established. Moreover, these observations may represent a novel and noninvasive diagnostic approach to assess the evolution of kidney function in hypertension and other chronic diseases.

Female Sexual Function and Its Association with the Severity of Menopause-Related Symptoms.

The aim of this study was to examine female sexual functioning and its association with the impact of the symptoms of menopause among Spanish postmenopausal women. A total of 182 postmenopausal women (65.59 ± 7.93 years) participated in this cross-sectional study. The female sexual function index (FSFI) and the menopause rating scale (MRS) were used to analyze sexual function and severity of menopausal symptoms, respectively. Age, education, area of residence, occupation, and depression (Hospital Anxiety and Depression Scale) were considered as possible confounders. The results of a linear multivariate regression analysis showed that the severity of urogenital menopause-related symptoms was associated with lower values in the FSFI total score and the lubrication, satisfaction, arousal, and orgasm domains. These last three subscales were also linked to severe psychological impact, while the MRS total score was only related to the desire domain. Regarding confounders, being younger, working, and residing in a rural area were all linked to better sexual function. All effect sizes were large (adjusted R2 > 0.35). In conclusion, after controlling for possible confounders, postmenopausal women who experience a severe impact of menopausal symptoms endure poorer sexual function, particularly when said symptoms are urogenital or psychological in nature.

Efecto de la ablación con catéter de venas pulmonares en la función renal de pacientes con fibrilación auricular. Estudio de cohortes prospectivo / Effect of pulmonary vein catheter ablation on kidney function in patients with atrial fibrillation. A prospective cohort study

INTRODUCCIÓN Y OBJETIVOS: Varios estudios han relacionado la presencia de fibrilación auricular (FA) con una tasa de filtrado glomerular estimada (TFGe) reducida. Nuestro objetivo es comparar la evolución de la TFGe en pacientes con FA tras ablación de venas pulmonares (VP) en función del éxito de la técnica, así como estudiar la relación entre TFGe y varios biomarcadores. MÉTODOS: Cohorte prospectiva de pacientes con FA remitidos a nuestro centro para ablación de VP con seguimiento de 1 año. La TFGe se obtuvo mediante la fórmula de la Chronic Kidney Disease Epidemiology Collaboration en el momento basal y a los 3 y 12 meses. Se midieron biomarcadores (péptido natriurético cerebral, corina y galectina-3) antes de la ablación y a los 12 meses. RESULTADOS: Se estudió a 124 pacientes (edad, 55±10 años; el 69,4% varones); 75 presentaban FA paroxística (60,5%). La media de la TFGe basal fue de 90,8 [77,8-100,0] ml/min/1,73 m2. La TFGe se incrementó al final del seguimiento, con diferencia estadísticamente significativa entre los pacientes que habían sufrido recurrencia a los 12 meses y los que no (-1,1 [-6,0 a 8,8] frente a 7,1 [-0,6 a 14,2] ml/min/1,73 m2; p = 0,017). La mejora de la TFGe a los 12 meses fue inversamente proporcional a la TFGe basal. Las cifras de péptido natriurético cerebral y corina mejoraron a los 12 meses, mientras que los de galectina-3 empeoraron, sin relación con la TFGe. CONCLUSIONES: En los pacientes con FA tratados con ablación de VP, se observó una mejora general de la TFGe, más marcada en el subgrupo que no tuvo recurrencias, aunque sin diferencias significativas en el análisis multivariante

INTRODUCTION AND OBJECTIVES: Several studies have linked the presence of atrial fibrillation (AF) with reduced estimated glomerular filtration rate (eGFR). Our objective was to compare changes in eGFR in patients with AF after pulmonary vein (PV) ablation depending on the success of the technique, as well as to examine the relationship between eGFR and several biomarkers. METHODS: Prospective cohort of patients with AF referred to our center for PV ablation with a 1-year follow-up. We estimated eGFR using the Chronic Kidney Disease Epidemiology Collaboration formula at baseline and at 3 and 12 months. Biomarkers (B-type natriuretic peptide, corin, and galectin-3) were measured before ablation and at 12 months. RESULTS: We studied 124 patients (age 55±10 years, 69.4% men). Seventy-five had paroxysmal AF (60.5%). The mean baseline eGFR was 90.8 [77.8-100.0] mL/min/1.73 m2. The eGFR increased at the end of follow-up, with a statistically significant difference between patients with recurrence at 12 months and those without (−1.1 [-6.0 to 8.8] mL/min/1.73 m2 vs 7.1 [−0.6 to 14.2] mL/min/1.73 m2, P=.017). The improvement in eGFR at 12 months was inversely proportional to baseline eGFR. B-type natriuretic peptide and corin levels improved at 12 months, while galectin-3 levels worsened, which was unrelated to eGFR. CONCLUSIONS: In patients with AF treated with PV ablation, an overall improvement in eGFR was observed, which was more marked in the subgroup without recurrences, although without significant differences on multivariate analysis

Effect of pulmonary vein catheter ablation on kidney function in patients with atrial fibrillation. A prospective cohort study.

INTRODUCTION AND OBJECTIVES: Several studies have linked the presence of atrial fibrillation (AF) with reduced estimated glomerular filtration rate (eGFR). Our objective was to compare changes in eGFR in patients with AF after pulmonary vein (PV) ablation depending on the success of the technique, as well as to examine the relationship between eGFR and several biomarkers. METHODS: Prospective cohort of patients with AF referred to our center for PV ablation with a 1-year follow-up. We estimated eGFR using the Chronic Kidney Disease Epidemiology Collaboration formula at baseline and at 3 and 12 months. Biomarkers (B-type natriuretic peptide, corin, and galectin-3) were measured before ablation and at 12 months. RESULTS: We studied 124 patients (age 55±10 years, 69.4% men). Seventy-five had paroxysmal AF (60.5%). The mean baseline eGFR was 90.8 [77.8-100.0] mL/min/1.73 m2. The eGFR increased at the end of follow-up, with a statistically significant difference between patients with recurrence at 12 months and those without (-1.1 [-6.0 to 8.8] mL/min/1.73 m2 vs 7.1 [-0.6 to 14.2] mL/min/1.73 m2, P=.017). The improvement in eGFR at 12 months was inversely proportional to baseline eGFR. B-type natriuretic peptide and corin levels improved at 12 months, while galectin-3 levels worsened, which was unrelated to eGFR. CONCLUSIONS: In patients with AF treated with PV ablation, an overall improvement in eGFR was observed, which was more marked in the subgroup without recurrences, although without significant differences on multivariate analysis.

The female sexual function index: reliability and validity in Spanish postmenopausal women.

OBJECTIVE: To examine the reliability and validity of the Spanish version of the Female Sexual Function Index (FSFI) and its ability to discriminate between women with and without female sexual dysfunction (FSD) among Spanish postmenopausal women. METHODS: A total of 152 postmenopausal women completed the Spanish version of FSFI. Internal consistency, test-retest reliability, and construct validity (exploratory factor analysis) were analyzed. Concurrent and divergent validity were assessed using a visual analog scale for overall satisfaction with sexual life and the Hospital Anxiety and Depression Scale, respectively. To determine the ability and the accuracy of the FSFI total score in discriminating between women with and without FSD, a receiver-operating characteristic curve analysis was performed. RESULTS: Factor analysis suggested a three-factor structure (explained variance 77.77%). The Spanish FSFI showed substantial-to-excellent test-retest reliability, with good internal consistency in the FSFI total score (Cronbach's alpha = 0.964), and also in its three dimensions. The FSFI total and domains scores showed strong (r > 0.50) and significant correlations (P < 0.01) with overall satisfaction with sexual life (concurrent validity), and low correlations with anxiety and depression (divergent validity). The Spanish FSFI total score and dimensions were significantly able to discriminate between women with and without FSD (P < 0.05), with an optimal cut-off point of <24.95 for the FSFI total score (64.15% sensitivity and 75.76% specificity). CONCLUSIONS: The Spanish FSFI is a valid and reliable instrument for assessing and discriminating for FSD among Spanish postmenopausal women.

Klotho and Aminopeptidases as Early Biomarkers of Renal Injury in Zucker Obese Rats.

The aim of this study was to investigate if urinary glutamyl aminopeptidase (GluAp), alanyl aminopeptidase (AlaAp), Klotho and hydroxyproline can be considered as potential biomarkers of renal injury and fibrosis in an experimental model of obesity. Male Zucker lean (ZL) and obese (ZO) rats were studied from 2 to 8 months old. Kidneys from ZO rats at the end of the study (8 months old) developed mild focal and segmental glomerulosclerosis as well as moderate tubulointerstitial injury. Urinary excretion of Klotho was higher in ZO rats at 2, 5, and 8 months of study, plasma Klotho levels were reduced and protein abundance of Klotho in renal tissue was similar in ZL and ZO rats. GluAp and AlaAp urinary activities were also increased in ZO rats throughout the time-course study. ZO rats showed an augmentation of hydroxyproline content in renal tissue and a significant increase of tubulointerstitial fibrosis. Correlation studies demonstrated that GluAp, AlaAp, and Klotho are early diagnostic markers of renal lesions in Zucker obese rats. Proteinuria and hydroxyproline can be considered delayed diagnostic markers because their contribution to diagnosis starts later. Another relevant result is that GluAp, AlaAp, and Klotho are related not only with diagnosis but also with prognosis of renal lesions in Zucker obese rats. Moreover, strong predictive correlations of aminopeptidasic activities with the percentage of renal fibrosis or with renal hydroxyproline content at the end of the experiment were observed, indicating that an early increased excretion of these markers is related with a higher later extent of fibrosis in Zucker obese rats. In conclusion, GluAp, AlaAp, and Klotho are early diagnostic markers that are also related with the extent of renal fibrosis in Zucker obese rats. Therefore, they have a potential use not only in diagnosis, but also in prognosis of obesity-associated renal lesions.

Thyroid hormones stimulate L-arginine transport in human endothelial cells

Thyroid hormone activity is associated with L-arginine metabolism and nitric oxide (NO) production, which participate in the cardiovascular manifestations of thyroid disorders. L-arginine transporters play an important role in activating L-arginine uptake and NO production. However, the effects of thyroid hormones on L-arginine transporters in endothelial cells have not yet been evaluated. The following methods were used. We measured L-arginine uptake, mRNA expression of L-arginine transporters, endothelial nitric oxide synthase (eNOS) mRNA and NO generation after the administration of T3, T4 and the T3 analog, 3,3',5-triiodothyroacetic acid TRIAC in human umbilical vein endothelial cells (HUVECs). We also analyzed the role of αvß3 integrin and of phosphatidyl-inositol-3 kinase (PI3K), mitogen-activated protein kinases (MAPKs: ERK1/2, p38 and SAPK-JNK) and intracellular calcium signaling pathways as underlying mechanisms. To this end, αvß3 integrin was pharmacologically inhibited by tetraiodothyroacetic acid (TETRAC) or genetically blocked by silencing αv mRNA and PI3K, MAPKs and intracellular calcium by selective inhibitors. The following results were obtained. Thyroid hormones and the T3 analog TRIAC increased L-arginine uptake in HUVECs, the sodium-independent y+/CAT isoforms, except CAT2b, sodium-dependent y+L system and sodium-independent system b0,+L-arginine transporters, eNOS mRNA and NO production. These effects were suppressed by αvß3 integrin inhibition with TETRAC or αv integrin downregulation or by PI3K, MAPK or intracellular Ca2+ signaling inhibitors. In conclusion, we report for the first time that activation of L-arginine uptake by thyroid hormones is related to an upregulation of L-arginine transporters. This effect seems to be mediated by activation of αvß3 integrin receptor and subsequent PI3K, MAPK and intracellular Ca2+ signaling pathways.

5-aminoisoquinoline improves renal function and fibrosis during recovery phase of cisplatin-induced acute kidney injury in rats.

The aim of the present study is to analyze the effects of 5-aminoisoquinoline (5-AIQ), a poly(ADP-ribose) polymerase-1 (PARP1) inhibitor, over renal dysfunction and fibrosis during recovery phase of cisplatin (CisPt)-induced acute kidney injury (AKI) in rats. Male Wistar rats were distributed in three groups (n=8 each group): control, CisPt, and CisPt + 5-AIQ. Control and CisPt groups received a subcutaneous injection of either saline or 7 mg/kg CisPt, respectively. CisPt + 5-AIQ group received two intraperitoneal injections of 10 mg/kg 5-AIQ 2 h before and 24 h after CisPt treatment. Thirteen days after the treatment, rats were housed in metabolic cages and 24-h urine collection was made. At day 14, CisPt-treated rats showed increased diuresis, N-acetyl-ß-d-glucosaminidase (NAG) excretion, glucosuria and sodium fractional excretion (NaFE), and decreased creatinine clearance (CrCl). 5-AIQ significantly increased CrCl and decreased NAG excretion, glucosuria, and NaFE. In plasma, CisPt increased sodium, urea, and creatinine concentrations, while 5-AIQ treatment decreased these variables to the levels of control group. 5-AIQ completely prevented the body weight loss evoked by CisPt treatment. CisPt also induced an increased renal expression of PAR polymer, α-smooth muscle actin (α-SMA), transforming growth factor-ß1 (TGF-ß1), and collagen-IV. These variables were decreased in CisPt + 5-AIQ group. Tubular lesions and renal fibrosis were also decreased by 5-AIQ treatment. We conclude that inhibition of PARP1 with 5-AIQ can attenuate long-term nephrotoxic effects associated with the CisPt treatment, preventing renal dysfunction and body weight decrease and ameliorating tubular lesions and collagen deposition.

Hyperthyroidism, but not hypertension, impairs PITX2 expression leading to Wnt-microRNA-ion channel remodeling.

PITX2 is a homeobox transcription factor involved in embryonic left/right signaling and more recently has been associated to cardiac arrhythmias. Genome wide association studies have pinpointed PITX2 as a major player underlying atrial fibrillation (AF). We have previously described that PITX2 expression is impaired in AF patients. Furthermore, distinct studies demonstrate that Pitx2 insufficiency leads to complex gene regulatory network remodeling, i.e. Wnt>microRNAs, leading to ion channel impairment and thus to arrhythmogenic events in mice. Whereas large body of evidences has been provided in recent years on PITX2 downstream signaling pathways, scarce information is available on upstream pathways influencing PITX2 in the context of AF. Multiple risk factors are associated to the onset of AF, such as e.g. hypertension (HTN), hyperthyroidism (HTD) and redox homeostasis impairment. In this study we have analyzed whether HTN, HTD and/or redox homeostasis impact on PITX2 and its downstream signaling pathways. Using rat models for spontaneous HTN (SHR) and experimentally-induced HTD we have observed that both cardiovascular risk factors lead to severe Pitx2 downregulation. Interesting HTD, but not SHR, leads to up-regulation of Wnt signaling as well as deregulation of multiple microRNAs and ion channels as previously described in Pitx2 insufficiency models. In addition, redox signaling is impaired in HTD but not SHR, in line with similar findings in atrial-specific Pitx2 deficient mice. In vitro cell culture analyses using gain- and loss-of-function strategies demonstrate that Pitx2, Zfhx3 and Wnt signaling influence redox homeostasis in cardiomyocytes. Thus, redox homeostasis seems to play a pivotal role in this setting, providing a regulatory feedback loop. Overall these data demonstrate that HTD, but not HTN, can impair Pitx2>>Wnt pathway providing thus a molecular link to AF.

Glutamyl aminopeptidase in microvesicular and exosomal fractions of urine is related with renal dysfunction in cisplatin-treated rats.

PURPOSE: The aim of this work was to investigate if the content of glutamyl aminopeptidase (GluAp) in microvesicular and exosomal fractions of urine is related with renal dysfunction in cisplatin-treated rats. METHODS: Urine samples were collected 24 hours after injection of cisplatin (7 mg/kg, n = 10) or saline serum (n = 10), and they were subjected to differential centrifugation at 1.000, 17.000 and 200.000 g to obtain microvesicular and exosomal fractions. GluAp was measured with a commercial ELISA kit in both fractions. Serum creatinine (SCr) and body weight were measured 15 days after treatment. We analyzed if early excretion of GluAp in microsomal and exosomal fractions was correlated with final SCr and body weight increase. In a second experiment, enzymatic activities of GluAp and alanyl aminopeptidase (AlaAp) in urine, microvesicular and exosomal fractions were measured three days after injection. We analyzed the correlation of both markers with SCr determined at this point. Finally, we studied the expression of GluAp and extracellular vesicles markers Alix and tumor susceptibility gene (TSG101) in both fractions by immunoblotting. RESULTS: GluAp excretion was increased in all fractions of urine after cisplatin treatment, even if data were normalized per mg of creatinine, per body weight or per total protein content of each fraction. We found significant predictive correlations with SCr concentration, and inverse correlations with body weight increase determined 15 days later. Three days after injection, aminopeptidasic activities were markedly increased in all fractions of urine in cisplatin-treated rats. The highest correlation coefficient with SCr was found for GluAp in microvesicular fraction. Increase of GluAp in microvesicular and exosomal fractions from cisplatin-treated rats was confirmed by immunoblotting. Alix and TSG101 showed different patterns of expression in each fraction. CONCLUSIONS: Determination of GluAp content or its enzymatic activity in microvesicular and exosomal fractions of urine is an early and predictive biomarker of renal dysfunction in cisplatin-induced nephrotoxicity. Measurement of GluAp in these fractions can serve to detect proximal tubular damage independently of glomerular filtration status.

L-Arginine metabolism in cardiovascular and renal tissue from hyper- and hypothyroid rats.

This study assessed the effects of thyroid hormones on the enzymes involved in l-arginine metabolism and the metabolites generated by the different metabolic pathways. Compounds of l-arginine metabolism were measured in the kidney, heart, aorta, and liver of euthyroid, hyperthyroid, and hypothyroid rats after 6 weeks of treatment. Enzymes studied were NOS isoforms (neuronal [nNOS], inducible [iNOS], and endothelial [eNOS]), arginases I and II, ornithine decarboxylase (ODC), ornithine aminotransferase (OAT), and l-arginine decarboxylase (ADC). Metabolites studied were l-arginine, l-citrulline, spermidine, spermine, and l-proline. Kidney heart and aorta levels of eNOS and iNOS were augmented and reduced (P < 0.05, for each tissue and enzyme) in hyper- and hypothyroid rats, respectively. Arginase I abundance in aorta, heart, and kidney was increased (P < 0.05, for each tissue) in hyperthyroid rats and was decreased in kidney and aorta of hypothyroid rats (P < 0.05, for each tissue). Arginase II was augmented in aorta and kidney (P < 0.05, for each tissue) of hyperthyroid rats and remained unchanged in all organs of hypothyroid rats. The substrate for these enzymes, l-arginine, was reduced (P < 0.05, for all tissues) in hyperthyroid rats. Levels of ODC and spermidine, its product, were increased and decreased (P < 0.05) in hyper- and hypothyroid rats, respectively, in all organs studied. OAT and proline levels were positively modulated by thyroid hormones in liver but not in the other tissues. ADC protein levels were positively modulated by thyroid hormones in all tissues. According to these findings, thyroid hormone treatment positively modulates different l-arginine metabolic pathways. The changes recorded in the abundance of eNOS, arginases I and II, and ADC protein in renal and cardiovascular tissues may play a role in the hemodynamic and renal manifestations observed in thyroid disorders. Furthermore, the changes in ODC and spermidine might contribute to the changes in cardiac and renal mass observed in thyroid disorders.

Tissue distribution of CysAP activity and its relationship to blood pressure and water balance.

AIMS: To better understand the functional role of soluble (Sol) and membrane-bound (MB) cystinyl-aminopeptidase (CysAP) activities, we studied differentially their organ distribution in adult male Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR)with or without treatment with captopril.We searched for a possible tissue-specific association of CysAP with water balance and blood pressure. MAIN METHODS: We used twenty WKY rats distributed in ten controls and ten captopril-treated, and sixteen SHR divided in eight controls and eight captopril-treated. Captopril (100 mg/kg/day) was administered in drinking water for 4 weeks. Systolic blood pressure, water intake and diuresis were measured individually. CysAP was assayed fluorometrically using L-cystine-di-ß-naphthylamide as substrate. KEY FINDINGS: Sol or MB activities were generally higher in SHR compared to WKY notably in hypothalamus and kidney than in the other tissues. Captopril mainly decreased CysAP in SHR whereas it increased in WKY. The distribution of Sol CysAP was more homogeneous among tissues ofWKY than SHR. In contrast, the distribution of MB CysAP was more heterogeneous than Sol CysAP in both WKY and SHR. This suggests that MB CysAP activity acts in a more tissue-specific manner than Sol CysAP. The majority of the significant correlations between tissue activities and the measured physiological parameters were observed mostly in renal medulla and hypothalamus. SIGNIFICANCE: Sol and MB CysAP activities, acting separately or in concert and mainly in renal medulla, regulate the function of their susceptible endogenous substrates, and may participate meaningfully in the control of blood pressure and fluid balance.

Effects of Arginase Inhibition in Hypertensive Hyperthyroid Rats.

BACKGROUND: This study analyzed the effects of chronic administration of N[omega]-hydroxy-nor-l-arginine (nor-NOHA), an inhibitor of arginase, on the hemodynamic, oxidative stress, morphologic, metabolic, and renal manifestations of hyperthyroidism in rats. METHODS: Four groups of male Wistar rats were used: control, nor-NOHA-treated (10 mg/kg/day), thyroxine (T4)-treated (75 µg/rat/day), and thyroxine- plus nor-NOHA-treated rats. All treatments were maintained for 4 weeks. Body weight, tail systolic blood pressure (SBP), and heart rate (HR) were recorded weekly. Finally, morphologic, metabolic, plasma, and renal variables were measured. Arginase I and II protein abundance and arginase activity were measured in aorta, heart, and kidney. RESULTS: The T4 group showed increased arginase I and II protein abundance, arginase activity, SBP, HR, plasma nitrates/nitrites (NOx), brainstem and urinary isoprostanes, proteinuria and cardiac and renal hypertrophy in comparison to control rats. In hyperthyroid rats, chronic nor-NOHA prevented the increase in SBP and HR and decreased proteinuria in association with an increase in plasma NOx and a decrease in brainstem and urinary isoprostanes. In normal rats, nor-NOHA treatment did not significantly change any hemodynamic, morphologic, or renal variables. Acute nor-NOHA administration did not affect renal or systemic hemodynamic variables in normal or T4-treated rats. CONCLUSION: Hyperthyroidism in rats is associated with the increased expression and activity of arginase in aorta, heart, and kidney. Chronic arginase inhibition with nor-NOHA suppresses the characteristic hemodynamic manifestations of hyperthyroidism in association with a reduced oxidative stress. These results indicate an important role for arginase pathway alterations in the cardiovascular and renal abnormalities of hyperthyroidism.

Interaction of neuropeptidase activities in cortico-limbic regions after acute restraint stress.

Brain enkephalin, vasopressin and oxytocin are anxiolytic agents involved in the stress response. Acute restraint stress influences certain neuropeptidase activities, such as some enkephalin-degrading peptidases and vasopressinase/oxytocinase, in the medial prefrontal cortex (mPFC), amygdala (AM) or hippocampus (HC), which are involved in this response. Because these regions form a unified circuit and cooperate in their response to stress, it is important to analyze the profile of the regional distribution of these activities as well as their inter-regional model of interaction in this circuit. Regarding the regional study, although most activities showed a marked predominance of the AM over the HC and mPFC, both in control and stressed animals, enkephalin-degrading activity, assayed as membrane-bound alanyl aminopeptidase activity, showed a change after stress, increasing in the HC and decreasing in the AM. The correlational study in controls indicated essentially a positive interaction between the mPFC and AM. In marked contrast, there was a highly significant change in the functional status of this circuit after stress, showing mainly a positive correlation between the mPFC and HC and between the AM and HC. The existence of correlations does not demonstrate a direct relationship between regions. However, reasons for such strong associations after restraint stress should be examined. The present study may indicate a connection between neuropeptidase activities and their corresponding neuropeptidergic substrates due to significant changes in the functional status of the cortico-limbic circuit after restraint stress.

Immunological detection of glutamyl aminopeptidase in urine samples from cisplatin-treated rats.

PURPOSE: The aim of this work is to demonstrate if urinary excretion of glutamyl aminopeptidase (GluAp) can be quantified by immunological methods. EXPERIMENTAL DESIGN: Urine samples from control and cisplatin-treated rats (n = 10 each group) were obtained at 1, 8, and 15 days after cisplatin injection. GluAp was analyzed by kinetic fluorimetry, ELISA, and immunoblotting. Sensitivity and specificity was studied for fluorimetric activity and ELISA 24 h after cisplatin injection. We also analyzed the predictive value over renal dysfunction at the end of the experiment. RESULTS: GluAp was easily detected by immunoblotting and ELISA, and its urinary excretion was increased in cisplatin-treated rats (p < 0.01). Results obtained with ELISA were strongly correlated (r = 0.8186; p < 0.0001) with fluorimetric activity. Kinetic fluorimetry was the method with the highest AUC (AUC = 1) and the highest predictive value over serum creatinine (r = 0.7630; p = 0.0001) and body weight increase (r = -0.8721; p < 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: GluAp can be detected in urine samples with immunological methods, making possible the development of an antibody-based kit for its determination. Its excretion correlates with the extent of renal dysfunction in cisplatin-treated rats, confirming its value as an early marker of renal damage that can be a diagnostic aid in renal diseases.

Dietary salt restriction in hyperthyroid rats. Differential influence on left and right ventricular mass.

This study assessed the impact of salt restriction on cardiac morphology and biochemistry and its effects on hemodynamic and renal variables in experimental hyperthyroidism. Four groups of male Wistar rats were used: control, hyperthyroid, and the same groups under low salt intake. Body weight, blood pressure (BP), and heart rate (HR) were recorded weekly for 4 weeks. Morphologic, metabolic, plasma, cardiac, and renal variables were also measured. Low salt intake decreased BP in T(4)-treated rats but not in controls. Low salt intake reduced relative left ventricular mass but increased absolute right ventricular weight and right ventricular weight/BW ratio in both control and hyperthyroid groups. Low salt intake increased Na(+)/H(+) exchanger-1 (NHE-1) protein abundance in both ventricles in normal rats but not in hyperthyroid rats, independently of its effect on ventricular mass. Mammalian target of rapamycin (mTOR) protein abundance was not related to left or right ventricular mass in hyperthyroid or controls rats under normal or low salt conditions. Proteinuria was increased in hyperthyroid rats and attenuated by low salt intake. In this study, low salt intake produced an increase in right ventricular mass in normal and hyperthyroid rats. Changes in the left or right ventricular mass of control and hyperthyroid rats under low salt intake were not explained by the NHE-1 or mTOR protein abundance values observed. In hyperthyroid rats, low salt intake also slightly reduced BP and decreased HR, proteinuria, and water and sodium balances.

Brain, heart and kidney correlate for the control of blood pressure and water balance: role of angiotensinases.

The renin-angiotensin system (RAS) plays a major role in the control of blood pressure (BP) and water balance by coordinating brain, heart and kidney functions, connected with each other by hormonal and neural mechanisms through the autonomic nervous system (ANS). RAS function may be monitored by the study of the enzymes (angiotensinases) involved in the metabolism of its active peptides. In order to study the relationship between the brain-heart-kidney axis and the control of BP and water balance, we analyzed the correlation of angiotensinase activities, assayed as arylamidase activities, between hypothalamus, left ventricle, renal cortex and renal medulla, collected from Wistar-Kyoto and spontaneously hypertensive rats, treated or not treated with L-NAME [N(G)-nitro-L-arginine methyl ester]. This compound not only inhibits the formation of nitric oxide but also disrupts the normal function of the ANS activating the sympathetic nervous system (SNS) to increase BP. In addition, to assess the influence of the SNS, we studied the effect of its blockade by treatment of both strains with propranolol. The present results support the notion that RAS function of the brain-heart-kidney axis, as reflected by the activities of angiotensinases, is reciprocally connected by afferent and efferent mechanisms between these locations, presumably through the ANS. These results reveal new aspects of neuroendocrine regulation possibly involving the ANS.

The pro-oxidant buthionine sulfoximine (BSO) reduces tumor growth of implanted Lewis lung carcinoma in mice associated with increased protein carbonyl, tubulin abundance, and aminopeptidase activity.

This study evaluated the effects of the pro-oxidant buthionine sulfoximine (BSO) and of the interaction between BSO and TETRAC, an antagonist of αvß3 integrin, on tumor development and aminopeptidase (AP) activity in a murine model of implanted Lewis's carcinoma. Male CBA-C57 mice were untreated (controls) or treated with BSO (222 mg/100 mL in drinking water), TETRAC (10 mg/kg/day, i.p.), or BSO + TETRAC. BSO for 28 days and TETRAC were given for the last 20 days. Mice were subcutaneously inoculated with 1 × 10(6) Lewis carcinoma 3LL cells into the dorsum. Study variables were tumor weight (TW); Hb, as index of tumor-mediated angiogenesis; vascular endothelial growth factor (VEGF) protein abundance; protein carbonyl content; α-tubulin abundance; and GluAp, AlaAp, and AspAp activities. BSO produced a major decrease in TW (203 ± 18 mg) with respect to controls (365 ± 26) and a reduction in Hb content. The TETRAC group also showed marked reductions in TW (129 ± 15) and Hb concentration associated with a reduced VEGF content. The BSO + TETRAC group showed a major TW reduction (125 ± 13); although, the difference with the TETRAC group was not significant. BSO treatment increased protein carbonyl and tubulin abundance in comparison to controls. The activity of all APs was increased in the three experimental groups and was strongly and negatively correlated with TW. In conclusion, administration of BSO reduced the TW, which inversely correlated with protein carbonyl content, suggesting a loss of microtubule polymerization. The finding of a negative correlation between TW and AP activity opens up new perspectives for the study of APs as tumor growth modulators.