Anogenital distance (AGD) plasticity in adulthood:Implications for its use as a biomarker of fetal androgen action

Androgen action during the fetal masculinization programming window (MPW) determines the maximum potential for growth of androgen-dependent organs (eg, seminal vesicles, prostate, penis, and perineum) and is reflected in anogenital distance (AGD). As such, determining AGD in postnatal life has potential as a lifelong easily accessible biomarker of overall androgen action during the MPW. However, whether the perineum remains androgen responsive in adulthood and thus responds plastically to perturbed androgen drive remains unexplored. To determine this, we treated adult male rats with either the antiandrogen flutamide or the estrogen diethylstilbestrol (DES) for 5 weeks, followed by a 4-week washout period of no treatment. We determined AGD and its correlate anogenital index (AGI) (AGD relative to body weight) at weekly intervals across this period and compared these with normal adult rats (male and female), castrated male rats, and appropriate vehicle controls. These data showed that, in addition to reducing circulating testosterone and seminal vesicle weight, castration significantly reduced AGD (by ∼17%), demonstrating that there is a degree of plasticity in AGD in adulthood. Flutamide treatment increased circulating testosterone yet also reduced seminal vesicle weight due to local antagonism of androgen receptor. Despite this suppression, surprisingly, flutamide treatment had no effect on AGD at any time point. In contrast, although DES treatment suppressed circulating testosterone and reduced seminal vesicle weight, it also induced a significant reduction in AGD (by ∼11%), which returned to normal 1 week after cessation of DES treatment. We conclude that AGD in adult rats exhibits a degree of plasticity, which may be mediated by modulation of local androgen/estrogen action. The implications of these findings regarding the use of AGD as a lifelong clinical biomarker of fetal androgen action are discussed

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Serelaxin as a potential treatment for renal dysfunction in cirrhosis: Preclinical evaluation and results of a randomized phase 2 trial

<div><p>Background</p><p>Chronic liver scarring from any cause leads to cirrhosis, portal hypertension, and a progressive decline in renal blood flow and renal function. Extreme renal vasoconstriction characterizes hepatorenal syndrome, a functional and potentially reversible form of acute kidney injury in patients with advanced cirrhosis, but current therapy with systemic vasoconstrictors is ineffective in a substantial proportion of patients and is limited by ischemic adverse events. Serelaxin (recombinant human relaxin-2) is a peptide molecule with anti-fibrotic and vasoprotective properties that binds to relaxin family peptide receptor-1 (RXFP1) and has been shown to increase renal perfusion in healthy human volunteers. We hypothesized that serelaxin could ameliorate renal vasoconstriction and renal dysfunction in patients with cirrhosis and portal hypertension.</p><p>Methods and findings</p><p>To establish preclinical proof of concept, we developed two independent rat models of cirrhosis that were characterized by progressive reduction in renal blood flow and glomerular filtration rate and showed evidence of renal endothelial dysfunction. We then set out to further explore and validate our hypothesis in a phase 2 randomized open-label parallel-group study in male and female patients with alcohol-related cirrhosis and portal hypertension. Forty patients were randomized 1:1 to treatment with serelaxin intravenous (i.v.) infusion (for 60 min at 80 μg/kg/d and then 60 min at 30 μg/kg/d) or terlipressin (single 2-mg i.v. bolus), and the regional hemodynamic effects were quantified by phase contrast magnetic resonance angiography at baseline and after 120 min. The primary endpoint was the change from baseline in total renal artery blood flow.</p><p>Therapeutic targeting of renal vasoconstriction with serelaxin in the rat models increased kidney perfusion, oxygenation, and function through reduction in renal vascular resistance, reversal of endothelial dysfunction, and increased activation of the AKT/eNOS/NO signaling pathway in the kidney. In the randomized clinical study, infusion of serelaxin for 120 min increased total renal arterial blood flow by 65% (95% CI 40%, 95%; <i>p <</i> 0.001) from baseline. Administration of serelaxin was safe and well tolerated, with no detrimental effect on systemic blood pressure or hepatic perfusion. The clinical study’s main limitations were the relatively small sample size and stable, well-compensated population.</p><p>Conclusions</p><p>Our mechanistic findings in rat models and exploratory study in human cirrhosis suggest the therapeutic potential of selective renal vasodilation using serelaxin as a new treatment for renal dysfunction in cirrhosis, although further validation in patients with more advanced cirrhosis and renal dysfunction is required.</p><p>Trial registration</p><p>ClinicalTrials.gov <a href="https://clinicaltrials.gov/ct2/show/NCT01640964" target="_blank">NCT01640964</a></p></div

Effect of acute serelaxin treatment on renal blood flow and tissue oxygenation in CCl₄ cirrhotic rats.

<p>Renal blood flow (RBF, A) and mean arterial pressure (MAP, B) responses to acute i.v. serelaxin (4 μg) or vehicle in 16-wk CCl₄ rats (<i>n =</i> 5–7). Measurement of velocity time integral (C) and renal resistive index (D) following acute i.v. serelaxin (4 μg) or vehicle (<i>n =</i> 6–8). Deoxygenated hemoglobin levels (R2*) in renal medulla in 8-wk (E) and 16-wk (F) CCl₄ rats at baseline, 30 min, and 60 min following acute i.v. serelaxin (4 μg) or vehicle (<i>n =</i> 5–8). Data presented as mean ± standard error of the mean, analyzed by two-way ANOVA (*<i>p <</i> 0.05; **<i>p <</i> 0.01; ***<i>p <</i> 0.001; NS, not significant) with post hoc Bonferroni correction to compare individual CCl₄ time points with respective vehicle controls (^#<i>p <</i> 0.05; ^##<i>p <</i> 0.01; ^###<i>p <</i> 0.001).</p

Effect of acute serelaxin treatment on renal blood flow and tissue oxygenation in CCl₄ cirrhotic rats.

<p>Renal blood flow (RBF, A) and mean arterial pressure (MAP, B) responses to acute i.v. serelaxin (4 μg) or vehicle in 16-wk CCl₄ rats (<i>n =</i> 5–7). Measurement of velocity time integral (C) and renal resistive index (D) following acute i.v. serelaxin (4 μg) or vehicle (<i>n =</i> 6–8). Deoxygenated hemoglobin levels (R2*) in renal medulla in 8-wk (E) and 16-wk (F) CCl₄ rats at baseline, 30 min, and 60 min following acute i.v. serelaxin (4 μg) or vehicle (<i>n =</i> 5–8). Data presented as mean ± standard error of the mean, analyzed by two-way ANOVA (*<i>p <</i> 0.05; **<i>p <</i> 0.01; ***<i>p <</i> 0.001; NS, not significant) with post hoc Bonferroni correction to compare individual CCl₄ time points with respective vehicle controls (^#<i>p <</i> 0.05; ^##<i>p <</i> 0.01; ^###<i>p <</i> 0.001).</p

Rat models of advanced cirrhosis, portal hypertension, and renal dysfunction.

<p>Portal pressure (PP; A), renal blood flow (RBF; B), and glomerular filtration rate (GFR; C) in 16-wk CCl₄ and olive oil (OO) control rats (<i>n =</i> 6–11). Representative H&E-stained kidney (scale bar 50 μm) showing minor tubular epithelial cell vacuolation (arrows) without significant necrosis after 16 wk of CCl₄ (D). PP (E), RBF (F), and GFR (G) in bile duct ligation (BDL) and sham-operated (sham) control rats (<i>n =</i> 4–8). Representative H&E-stained kidney (scale bar 50 μm) showing necrotic cells within the tubule lumen and loss of the normal circumferential epithelial cell population (arrows) 4 wk after BDL (H). Data presented as mean ± standard error of the mean, analyzed by one-way ANOVA with post hoc Bonferroni correction (*<i>p <</i> 0.05; **<i>p <</i> 0.01; ***<i>p <</i> 0.001).</p

Effect of sustained serelaxin infusion on AKT/eNOS/NO signaling in cirrhotic rat kidney.

<p>Quantification of p-eNOS/eNOS and p-AKT/AKT in whole kidney extracts from 72-h serelaxin- or vehicle-treated 16-wk CCl₄ and 4-wk bile duct ligation (BDL) rats (<i>n =</i> 4) (A–F). Data presented as mean ± standard error of the mean (SEM), analyzed by unpaired <i>t</i>-test (*<i>p <</i> 0.05; **<i>p <</i> 0.01; ***<i>p <</i> 0.001). NOS activity in whole kidney extracts from CCl₄ (G) and BDL (H) rats treated with serelaxin or vehicle (<i>n =</i> 6–8). Data presented as mean ± SEM, analyzed by unpaired <i>t</i>-test (*<i>p <</i> 0.05; **<i>p <</i> 0.01). Renal blood flow (RBF; I) and glomerular filtration rate (GFR; J) in 16-wk CCl₄ rats co-treated with L-N^G-nitroarginine methyl ester (L-NAME) (<i>n =</i> 4–8). Data presented as mean ± SEM, analyzed by one-way ANOVA with post hoc Bonferroni correction (*<i>p <</i> 0.05; **<i>p <</i> 0.01; ***<i>p <</i> 0.001). OO, olive oil.</p