Testosterona inhibe la actividad de la aldosterona sintasa silvestre y quimérica in vitro

Background: Familial hyperaldosteronism type I is caused by the generation of a chimeric aldosterone synthase enzyme (ASCE) which is regulated by ACTH instead of angiotensin II. We have reported that in vitro, the wild-type (ASWT) and chimeric aldosterone synthase (ASCE) enzymes are inhibited by progesterone and estradiol does not affect their activity. Aim: To explore the direct action of testosterone on ASWT and ASCE enzymes. Material and Methods: HEK-293 cells were transiently transfected with vectors containing the full ASWT or ASCE cDNAs. The effect of testosterone on AS enzyme activities was evaluated incubating HEK-cells transfected with enzyme vectors and adding deoxycorticosterone (DOC) alone or DOC plus increasing doses of testosterone. Aldosterone production was measured by HPLC-MS/MS. Docking of testosterone within the active sites of both enzymes was performed by modelling in silico. Results: In this system, testosterone inhibited ASWT (90% inhibition at five pM, 50% inhibitory concentration (IC50) =1.690 pM) with higher efficacy andpotency than ASCE (80% inhibition at five pM, IC50=3.176 pM). Molecular modelling studies showed different orientation of testosterone in ASWT and ASCE crystal structures. Conclusions: The inhibitory effect of testosterone on ASWT or ASCE enzymes is a novel non-genomic testosterone action, suggesting that further clinical studies are needed to assess the role of testosterone in the screening and diagnosis of primary aldosteronism.

Variación estacional de 25-hidroxi-vitamina D3, hormona paratiroidea y fosfatasa alcalina en niños escolares / Seasonal variations in 25-hydroxy vitamin D3, parathormone and alkaline phosphatase in school-aged children

INTRODUCCIÓN: El principal rol de la vitamina D es la regulación del metabolismo del calcio, cuya principal fuen te es la vitamina D3 que se obtiene principalmente por la acción de la luz ultravioleta (UV) en la piel. OBJETIVO: Evaluar las diferencias estacionales en las concentraciones de 25-hidroxi-vitamina D3 (25OHVitD3), hormona paratiroidea (PTH), fosfatasa alcalina (FA) y calcio en niños en edad esco lar. SUJETOS Y MÉTODO: Se midieron las concentraciones de 25OHVitD3, PTH, FA y calcio en niños de 5 a 8 años, sin suplementación de Vitamina D, reclutados en Santiago de Chile (latitud -33.4372) en distintas estaciones del año. El estatus de VitD fue definido como suficiente con concentraciones de 25OHVitD3 > 20 ng/mL (50 nmol/L), insuficiente 12-20 ng/mL (30-50 nmol/L) y deficiente 20 ng/mL) en verano, lo que disminuyó significativamente en invierno (54,3%, p < 0,0001). CONCLUSIONES: Las concentraciones de 25OHVitD3 disminuyeron en aproximadamente la mitad de los niños durante el invierno, lo que se vio acompañado de un aumento de la PTH y FA, asociado a concentraciones normales de calcio. De acuerdo a nuestros resultados, la suplementación con VitD en niños podría ser necesaria durante otoño e invierno.

INTRODUCTION: The main role of Vitamin D is to regulate calcium metabolism, whose main source is vitamin D3 ob tained mostly from the action of ultraviolet (UV) light on the skin. OBJECTIVE: To evaluate the seaso nal differences in the concentrations of 25-hydroxy-vitamin D3 (25OHVitD3), parathyroid hormone (PTH), alkaline phosphatase (ALP), and calcium in school-age children. SUBJECTS AND METHOD: The concentrations of 25OHVitD3, PTH, ALP, and calcium were measured in children from Santiago, Chile (latitude -33.4372), aged 5 to 8 years, without Vitamin D supplementation, in different seasons of the year. VitD status was defined as sufficient with concentrations of 25OHVitD3 >20 ng/mL (50 nmol/L), insufficient 12-20 ng/mL (30-50 nmol/L) and deficient 20 ng/mL), which decreased significantly in winter to 54.3% (p <0.0001). CONCLUSIONS: In winter, 25OHVitD3 concentrations decreased in approximately half of the children, which was associated with an increase in PTH and ALP, and normal calcium concentrations. According to our results, children may need VitD supple mentation during fall and winter.

¿Como optimizar el diagnóstico funcional de los incidentalomas suprrarenales? Importancia de un estudio protocolizado / How to optimize the functional diagnosis of suprarenal incidenta- lomas? Importance of a protocolized study

Adrenal incidentalomas are an increasingly common pathology. Although historically they have been considered largely non-functioning, recent evidence suggests that the usually performed study is incomplete and/or not sensitive enough. In the last decade the clinical spectrum of adrenal hypercortisolism has expanded considerably, including milder cases which are also associated with cardiovascular morbidity and even mortality. Furthermore, primary aldosteronism has also expanded beyond the classic phenotype with advanced vascular damage, resistant hypertension and hypokalemia, currently including asymptomatic, normotensive and normokalemic patients. For this reason, a correct protocolized study is essential in all adrenal incidentalomas, including a precise radiological characterization, as well as a systematic hormonal evaluation using more sensitive cut points. The findings of this workup are relevant, because they allow a more individualized approach to the medical and surgical management of these patients.

Los incidentalomas suprarrenales son una patología cada vez más frecuente. Si bien históricamente han sido considerados no funcionantes en su gran mayoría, evidencia reciente sugiere que el estudio habitual es incompleto y/o poco sensible. En la última década el espectro clínico del hipercortisolismo de origen adrenal se ha ampliado de forma considerable, incluyendo casos leves que también se asocian a morbilidad cardiovascular e incluso mortalidad. Por otro lado, el hiperaldosteronismo primario también ha expandido su fenotipo más allá del clásicamente descrito con daño vascular avanzado, hipertensión resistente e hipokalemia, abarcando en la actualidad a pacientes asintomáticos, normotensos y normokalemicos. Por esta razón es imprescindible un correcto estudio protocolizado en todo incidentaloma suprarrenal, incluyendo una precisa caracterización radiológica, así como una evaluación hormonal sistemática utilizando puntos de corte más sensibles. Los hallazgos de este estudio son relevantes, pues permiten guiar de forma más individualizada el manejo médico y quirúrgico de estos pacientes.

Estudio e identificación de microRNA en exosomas urinarios en hipertensión arterial mineralocorticoide / Study and identification of microRNA in urinary exosomes in mineralocorticoid arterial hypertension

About 15% of the essential hypertensive patients would have a low activity of the 11ßHSD2 enzyme, which inactivates cortisol (F) to cortisone (E). Gene expression can be negatively regulated by miRNA. Urinary exosomes and their specific content (miRNA/proteins) represent a valuable tool as a biomarker for the diagnosis and prognosis of the disease. Aim: To evaluate the expression of miRNA specific for 11ßHSD2 in samples of urinary exosomes and to determine its association with biochemical variables associated with mineralocorticoid metabolism. Subjects and Methods: Cross-sectional study in subjects between 10-60 years. They were classified into subjects with high F/E (> p75) and low cortisone (< p25) and control subjects. The urinary exosomes were isolated with the Invitrogen kit. Bioinformatic analysis was performed with Mir Walk to identify specific miRNAs of HSD11B2. The expression of miRNA was evaluated by qRT PCR. The comparisons were made with the Mann-Whitney test. Results: 7.1% of the subjects are suggestive of a partial deficiency of 11ßHSD2 (NC-AME). The expression of miR-488 was higher in NC-AME than in controls (5839 ± 1719 vs 3,437 ± 2,581; p = 0.01). We found positive associations between mir-615 and ARP; miR-488 and the sodium/potassium ratio; miR-1205 with age and urinary sodium excretion; miR-494 with age, activity MMP9 and NGAL. Conclusion: We identified high expression of miR488 in NC-AME subjects and associations of miRNAs with biochemical variables associated with mineralocorticoid metabolism. Thus, exosomes and their miRNA content could be potential regulators and biomarkers of 11ßHSD2 activity.

Identificación bacteriana basada en el espectro de masas de proteínas: Una nueva mirada a la microbiología del siglo XXI / Bacterial identification based on protein mass spectrometry: A new insight at the microbiology of the 21st century

Bacterial identification is important for the proper treatment of infected patients hospitalized with serious infections especially in critical care units. Identification by conventional methods used in microbiology laboratories takes at least 16 hours since a culture is positive. The introduction of mass spectrometry, specifically MALDI-TOF MS (matrix-assisted laser desorption/ ionization time-of-flight mass spectrometer) in the microbiology laboratory could mean a radical change in the identification accuracy, turn around time (6 minutes per bacteria) and cost (about 5 times cheaper than conventional identification). Since its introduction in clinical microbiology laboratories in 2008, many reports about its usefulness in identifying microorganisms from colonies, as well as directly from positive blood cultures and urine samples have been published. This review describes MALDI-TOF MS methodology, its identification performance for bacteria (aerobic and anaerobic), mycobacterium and yeasts, its future applications in microbiology and its main disadvantages.

La identificación bacteriana es muy importante en el manejo adecuado de los pacientes infectados, especialmente aquellos con infecciones graves hospitalizados en unidades de pacientes críticos. La identificación por los métodos convencionales utilizados en los laboratorios de microbiología clínica demora al menos 16 horas desde que un cultivo es positivo. La introducción de la espectrometría de masas, específicamente del espectrómetro de masas por tiempo de migración (tiempo de vuelo) con desorción/ionización laser asistida por una matriz (MALDI-TOF MS, por su sigla en inglés matrix-assisted laser desorption/ionization time-of-flight mass spectrometer), en el laboratorio de microbiología podría significar un cambio radical en la precisión de la identificación, el tiempo de detección (6 minutos por bacterias) y el costo (aproximadamente 5 veces más económico que la identificación convencional). Desde su introducción en los laboratorios de microbiología clínica en el año 2008, se han escrito numerosas publicaciones sobre su utilidad en la identificación de microorganismos desde colonias, así como directamente desde hemocultivos positivos y de muestras de orina. Esta revisión describe la metodología de MALDI-TOF MS, su rendimiento en la identificación de bacterias aerobias, anaerobias, micobacterias y levaduras, sus futuras aplicaciones en microbiología y sus principales desventajas.