Combined Sabal and Urtica Extracts (WS® 1541) Exert Anti-proliferative and Anti-inflammatory Effects in a Mouse Model of Benign Prostate Hyperplasia

WS® 1541 is a phytopharmaceutical drug combination containing a lipophilic extract from fruits of Sabal serrulata (WS® 1473) and an aqueous ethanolic extract from roots of Urtica dioica (WS® 1031). It is approved in several countries worldwide for the treatment of lower urinary tract syndrome (LUTS) linked to benign prostate hyperplasia (BPH). Clinical studies have demonstrated the efficacy of this unique combination in the treatment of BPH-related LUTS. However, its mechanisms of action in vivo remain partly uncharacterized. The aim of this study was to take advantage of a validated mouse model of BPH to better characterize its growth-inhibitory and anti-inflammatory properties. We used the probasin–prolactin (Pb-PRL) transgenic mouse model in which prostate-specific overexpression of PRL results in several features of the human disease including tissue hypertrophy, epithelial hyperplasia, increased stromal cellularity, inflammation, and LUTS. Six-month-old heterozygous Pb-PRL male mice were randomly distributed to five groups (11–12 animals/group) orally treated for 28 consecutive days with WS® 1541 (300, 600, or 900 mg/kg/day), the 5α-reductase inhibitor finasteride used as reference (5 mg/kg/day) or vehicle (olive oil 5 ml/kg/day). Administration of WS® 1541 was well tolerated and caused a dose-dependent reduction of prostate weight (vs. vehicle) that was statistically significant at the two highest doses. This effect was accompanied by a reduction in prostate cell proliferation as assessed by lower Ki-67 expression (qPCR and immunohistochemistry). In contrast, finasteride had no or only a mild effect on these parameters. The growth-inhibitory activity of WS® 1541 was accompanied by a strong anti-inflammatory effect as evidenced by the reduced infiltration of cells expressing the leukocyte common antigen CD45. In sharp contrast, finasteride significantly increased the prostate inflammatory status according to this readout. Molecular profiling (qPCR) of 23 selected pro-inflammatory genes confirmed the strong anti-inflammatory potency of WS® 1541 compared to finasteride. Since treatment of WS® 1541 did not interfere with transgene expression and activity in the prostate of Pb-PRL mice, the effects observed in this study are entirely attributable to the intrinsic pharmacological action of the drug combination

The effect of 5-HT and electrical field stimulation on the contractility of the whole isolated urinary bladder of Suncus murinus

The present study used the whole isolated urinary bladder of Suncus murinus, to investigate the effect of exogenously added serotonin (5-HT) and electrical field stimulation (EFS) in the absence and presence of methysergide, a 5-HT1/2/7 receptor antagonist or the selective 5-HT7 receptor antagonist, SB269970. Further experiments investigated the involvement of potassium channel, cholinergic and purinergic systems in mediating the contractile response to EFS. Pre-treatment with methysergide reduced and increased the contractile responses to 5-HT and EFS, respectively. Pre-treatment with SB269970 increased the responses to 5-HT without modifying the EFS-induced contractions. EFS-induced contractions were not modified by pre-treatment with atropine (10 μM), α-β-methylene ATP or glibenclamide. EFS-induced contractions were attenuated by cromakalim or atropine (<1 μM). In conclusion, the 5-HT2 receptors are likely to play a role in mediating the contractile response to 5-HT in detrusor muscle. Furthermore, EFS-induced contractions are mediated through cholinergic and an unknown neurotransmitter which is modulated by K(ATP ) channels in the detrusor muscle of Suncus murinus

NETUPITANT, A POTENT AND HIGHLY SELECTIVE NK1 RECEPTOR ANTAGONIST, ALLEVIATES ACETIC ACID-INDUCED BLADDER OVERACTIVITY IN ANESTHETIZED GUINEA-PIGS

Introduction. Tachykinins potently contract the isolated urinary bladder from a number of animal species and play an important role in the regulation of the micturition reflex. On the guinea-pig isolated urinary bladder we examined the effects of a new potent and selective NK1 receptor antagonist (netupitant) on the contractions induced by a selective NK1 receptor agonist, SP-methylester (SP-OMe). Moreover, the effects of netupitant and another selective NK1 antagonist (L-733,060) were studied in anesthetized guinea-pigs using two experimental models, the isovolumetric bladder contractions and a model of bladder overactivity induced by intravesical administration of acetic acid (AA). Methods and Results. Detrusor muscle strips were mounted in 5 mL organ baths and isometric contractions to cumulative concentrations of SP-OME were recorded before and after incubation with increasing concentrations of netupitant. In anesthetized female guinea-pigs, reflex bladder activity was examined under isovolumetric conditions with the bladder distended with saline or during cystometry using intravesical infusion of acetic acid (AA). After a 30 min stabilization period, netupitant (0.1-3 mg/kg, i.v.) or L-733,060 (3-10 mg/kg, i.v.) were administered. In the detrusor muscle, netupitant produced a concentration-dependent inhibition (mean pKB = 9.24) of the responses to SP-OMe. Under isovolumetric conditions, netupitant or L-733,060 reduced bladder contraction frequency in a dose-dependent manner, but neither drug changed bladder contraction amplitude. In the AA model, netupitant dose-dependently increased intercontraction interval (ICI) but had no effect on the amplitude of micturition (AM). L-733,060 dose-dependently increased ICI also but this effect was paralleled by a significant reduction of AM. Conclusion. Netupitant decreases the frequency of reflex bladder contractions without altering their amplitude, suggesting that this drug targets the afferent limb of the micturition reflex circuit and therefore may be useful clinically in treating bladder overactivity symptoms

G protein-coupled receptors, an unexploited animal toxin targets: Exploration of green mamba venom for novel drug candidates active against adrenoceptors.

International audienceAt a time when pharmaceutical companies are having trouble finding new low MW drugs and when biologics are becoming more common, animal venoms could constitute an underexploited source of novel drug candidates. We looked for identifying novel animal toxins active against G protein-coupled receptors (GPCR), the most frequently exploited class of treatment targets, with the aim to develop novel research tools and drug candidates. Screening of green mamba (Dendroaspis angusticeps) venom against adrenoceptors identified two novel venom peptides. ρ-Da1a shown an affinity of 0.35 nM for the α1a-AR while ρ-Da1b displayed affinities between 14 and 73 nM for the three α2-ARs. These two venom peptides have sequences similar to those of muscarinic toxins and belong to the three-finger-fold protein family. α1a-AR is the primary target for the treatment of prostate hypertrophy. In vitro and in vivo tests demonstrated that ρ-Da1a reduced prostatic muscle tone as efficiently as tamsulosin (an antagonist presently used), but with fewer cardiovascular side effects. α2-ARs are the prototype of GPCRs not currently used as treatment targets due to a lack of specific ligands. Blockage of these receptors increases intestinal motility, which may be compromised by abdominal surgery and reduces orthosteric hypotension. In vitro and in vivo tests demonstrated that ρ-Da1b antagonizes α2-ARs in smooth muscles and increased heart rate and blood catecholamine concentrations. These results highlight possible exploitation of ρ-Da1a and ρ-Da1b in important pathologies

A snake toxin as a theranostic agent for the type 2 vasopressin receptor

International audienceRationale: MQ1, a snake toxin which targets with high nanomolar affinity and absolute selectivity for the type 2 vasopressin receptor (V2R), is a drug candidate for renal diseases and a molecular probe for imaging cells or organs expressing V2R. Methods: MQ1's pharmacological properties were characterized and applied to a rat model of hyponatremia. Its PK/PD parameters were determined as well as its therapeutic index. Fluorescently and radioactively labeled MQ1 were chemically synthesized and associated with moderate loss of affinity. MQ1's dynamic biodistribution was monitored by positron emission tomography. Confocal imaging was used to observe the labeling of three cancer cell lines. Results: The inverse agonist property of MQ1 very efficiently prevented dDAVP-induced hyponatremia in rats with low nanomolar/kg doses and with a very large therapeutic index. PK (plasma MQ1 concentrations) and PD (diuresis) exhibited a parallel biphasic decrease. The dynamic biodistribution showed that MQ1 targets the kidneys and then exhibits a blood and kidney biphasic decrease. Whatever the approach used, we found a T1/2α between 0.9 and 3.8 h and a T1/2β between 25 and 46 h and demonstrated that the kidneys were able to retain MQ1. Finally, the presence of functional V2R expressed at the membrane of cancer cells was, for the first time, demonstrated with a specific fluorescent ligand. Conclusion: As the most selective V2 binder, MQ1 is a new promising drug for aquaresis-related diseases and a molecular probe to visualize in vitro and in vivo V2R expressed physiologically or under pathological conditions