Aumento de la lipocalina orosomucoide-1 (ORM1) en sujetos con hiperaldosteronismo primario / Increase of lipocalin ORM1 in primary aldosteronism

El hiperaldosteronismo primario (HAP) es la causa más común de hipertensión arterial secundaria. A pesar de la prevalencia del HAP (6-10%) y sus consecuencias, los mecanismos que median los efectos deletéreos renales y extrarenales originados por la aldosterona más allá de la hipertensión arterial (ej. inflamación renal, alteraciones cardiacas y disfunción vascular), siguen siendo poco conocidos. Estudios previos sugieren que el exceso de aldosterona aumentaría proteínas sensibles a la activación del receptor de mineralocorticoides (MR), como las lipocalinas LCN2 (NGAL) y ORM1. OBJETIVO: Determinar la concentración de las lipocalinas ORM1, NGAL y NGAL-MMP9 en sujetos HAP. SUJETOS Y MÉTODOS: Estudio de cohorte transversal en sujetos adultos (similares en sexo, edad e IMC) separados en controles normotensos (CTL), hipertensos esenciales (HE) y con screening positivo de HAP (aldosterona ≥9 ng/dL y ARP < 1 ng/mL*h acorde a las guías internacionales de HAP). Se determinó la presión arterial sistólica (PAS) y diastólica (PAD), aldosterona plasmática, actividad renina plasmática (ARP) y la relación aldosterona / actividad de renina plasmática (ARR). Se determinó la concentración de NGAL, NGAL-MMP9 y ORM1 en suero por ELISA. RESULTADOS: Detectamos mayores niveles de ORM1 en sujetos HAP. No se detectaron diferencias en NGAL ni NGAL-MMP9 entre los grupos. Detectamos una asociación positiva de ORM1 con ARP (rho= -0,407, p=0,012) y con ARR (rho= 0,380 p= 0,021). CONCLUSIÓN: La mayor concentración de ORM1 en sujetos HAP y las asociaciones de ORM1 con aldosterona, ARP y ARR, proponen a esta proteína como un potencial biomarcador de HAP y de utilidad en el desarrollo de algoritmos diagnósticos de HAP.

Primary hyperaldosteronism (PA) is the most common cause of secondary hypertension. Despite the prevalence of PA (6-10%) and its consequences, the mechanisms that mediate the deleterious renal and extrarenal effects caused by aldosterone beyond arterial hypertension (eg renal inflammation, cardiac alterations and vascular dysfunction), remain barely known. Previous studies suggest that excess aldosterone would increase proteins sensitive to activation of the mineralocorticoid receptor (MR), such as lipocalins LCN2 (NGAL) and ORM1. AIM: To determine the concentration of the lipocalins ORM1, NGAL and NGAL-MMP9 in PA subjects. SUBJECTS AND METHODS: Cross-sectional study in adult subjects (similar in sex, age and BMI) grouped as normotensive controls (CTL), essential hypertensive (HE) and subjects with positive PA screening (aldosterone ≥ 9 ng/dL and PRA <1 ng/mL*h, according to international PA guidelines). Systolic (SBP) and diastolic (DBP) blood pressure, plasma aldosterone, plasma renin activity (PRA), and plasma aldosterone renin ratio (ARR) were determined. The concentration of NGAL, NGAL-MMP9 and ORM1 in serum was determined by ELISA. RESULTS: We detected higher levels Recibido: 03-09-2021 of ORM1 in PA subjects. No differences in NGAL or NGAL-MMP9 were detected between the groups. We detected a positive association of ORM1 with ARP (rho = -0.407, p < 0.05) and with ARR (rho = 0.380 p <0.05). CONCLUSION: The high levels of ORM1 in PA subjects and the associations of ORM1 with aldosterone, ARP and ARR, suggest ORM1 is a potential biomarker of PA, and useful in the development of a diagnostic algorithm for PA.

Divergent short- and long-term effects of acute stress in object recognition memory are mediated by endogenous opioid system activation.

Acute stress induces short-term object recognition memory impairment and elicits endogenous opioid system activation. The aim of this study was thus to evaluate whether opiate system activation mediates the acute stress-induced object recognition memory changes. Adult male Wistar rats were trained in an object recognition task designed to test both short- and long-term memory. Subjects were randomly assigned to receive an intraperitoneal injection of saline, 1 mg/kg naltrexone or 3 mg/kg naltrexone, four and a half hours before the sample trial. Five minutes after the injection, half the subjects were submitted to movement restraint during four hours while the other half remained in their home cages. Non-stressed subjects receiving saline (control) performed adequately during the short-term memory test, while stressed subjects receiving saline displayed impaired performance. Naltrexone prevented such deleterious effect, in spite of the fact that it had no intrinsic effect on short-term object recognition memory. Stressed subjects receiving saline and non-stressed subjects receiving naltrexone performed adequately during the long-term memory test; however, control subjects as well as stressed subjects receiving a high dose of naltrexone performed poorly. Control subjects' dissociated performance during both memory tests suggests that the short-term memory test induced a retroactive interference effect mediated through light opioid system activation; such effect was prevented either by low dose naltrexone administration or by strongly activating the opioid system through acute stress. Both short-term memory retrieval impairment and long-term memory improvement observed in stressed subjects may have been mediated through strong opioid system activation, since they were prevented by high dose naltrexone administration. Therefore, the activation of the opioid system plays a dual modulating role in object recognition memory.