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Abstract: Sfmbt2-hosted miR-466a-3p and its close relatives are often among the most significantly up-regulated or down-regulated miRNAs in responses to numerous deleterious environmental stimuli. The exact roles of these miRNAs in cellular stress responses, however, are not clear. Here we showed that many Sfmbt2-hosted miRNAs were highly hypertonic stress responsive in vitro and in vivo. In renal medulla, water deprivation induced alterations in the expression of miR-466(a/b/c/e/p)-3p in a pattern similar to that of miR-200b-3p, a known regulator of osmoresponsive transcription factor Nfat5. Remarkably, exposure of mIMCD3 cells to an arginine vasopressin analog time-dependently down-regulated the expression of miR-466(a/b/c/e/p)-3p and miR-200b-3p, which provides a novel regulatory mechanism for these osmoresponsive miRNAs. In cultured mIMCD3 cells we further demonstrated that miR-466a-3p and miR-466g were capable of targeting Nfat5 by interacting with its 3′UTR. In transgenic mice overexpressing miR-466a-3p, significant down-regulation of Nfat5 and many other osmoregulation-related genes was observed in both the renal cortex and medulla. Moreover, sustained transgenic over-expression of miR-466a-3p was found to be associated with polydipsia, polyuria and disturbed ion homeostasis and kidney morphology. Since the mature sequence of miR-466a-3p is completely equivalent to that of miR-466e-3p and that the seed sequence of miR-466a-3p is completely equivalent to that of miR-297(a/b/c)-3p, miR-466d-3p, miR-467g and miR-669d-3p, and that miR-466a-3p differs from miR-466(b/c/p)-3p only in a 5′ nucleotide, we propose that miR-466a-3p and many of its close relatives are important epigenetic regulators of renal Nfat5 signaling, osmoregulation and urine concentration in mice. [Copyright &y& Elsevier]

Abstract: Objective: Available clinical data raise the possibility that stress-adaptive mechanisms differ by gender. However, this notion has not been rigorously tested in relation to cortisol-mediated negative feedback. Materials/Methods: Degree of ACTH inhibition during and recovery from an experimental cortisol clamp was tested in 20 healthy older subjects (age 60±2.2y). Volunteers received oral placebo or ketoconazole (KTCZ) to inhibit adrenal steroidogenesis along with i.v. infusions of saline or a low vs high physiological dose of cortisol in a prospectively randomized double-blind, placebo-controlled design. ACTH and cortisol concentrations were measured every 10min during the feedback-clamp phase and thereafter (recovery or escape phase). Corticosteroid-binding globulin (CBG) was measured, and free cortisol concentrations were calculated. Results: Gender did not determine mean ACTH concentrations during the saline or cortisol feedback-clamp phases per se. However, women had markedly impaired ACTH recovery after stopping both low- and high-dose cortisol infusions compared with men (P =0.005, KTCZ/low-dose cortisol arm; and P =0.006, KTCZ/high-dose cortisol arm). Decreased ACTH recovery in women was accompanied by lower total and free cortisol concentrations, pointing to heightened feedback inhibition of hypothalamo-pituitary drive of ACTH secretion as the main mechanism. Conclusions: In summary, gender or a factor related to gender, such as sex steroids or body composition, determines recovery of ACTH secretion from cortisol-enforced negative feedback. Attenuated ACTH recovery in post-menopausal women may have relevance to sex differences in stress-related adaptations. [Copyright &y& Elsevier]

Purpose: Alpha-blockers improve lower urinary tract symptoms associated with benign prostatic obstruction. Nocturia, a storage symptom, is a common complaint in men. However, it does not fully respond to α-blocker therapy, likely due to its multifactorial pathophysiology. We evaluated the efficacy and safety of desmopressin as add-on therapy for refractory nocturia in men previously treated with an α-blocker for lower urinary tract symptoms. Materials and Methods: Eligible patients were men 50 years old or older with lower urinary tract symptoms and persistent nocturia despite α-blocker treatment for a minimum of 4 weeks. The optimum dose of oral desmopressin was determined during a 4-week dose titration period and this dose was maintained for 24 weeks. Flow volume charts, International Prostate Symptom Score total and subscores, uroflowmetry and post-void residual urine volume were assessed. Results: A total of 216 patients were enrolled in the study. Of these patients there were 158 (76%) with nocturnal polyuria, 15 (7.2%) with decreased nocturnal bladder capacity and 35 (16.8%) with nocturia due to both causes. The number of nocturnal voids significantly decreased from a baseline mean of 7.0 to 5.7 episodes for 3 days at the 24-week visit. The average International Prostate Symptom Score total and subscore significantly decreased by 4 weeks and were maintained at 24 weeks. In patients younger than 65 years, International Prostate Symptom Score voiding subscores were significantly improved at 24 weeks compared to those age 65 years or older. Conclusions: Desmopressin add-on therapy for refractory nocturia in men previously treated with an α-blocker for lower urinary tract symptoms improved voiding symptoms as well as nocturia, storage symptoms. [Copyright &y& Elsevier]