Mechanisms by which a phytotherapeutic drug influences bladder activity in rats

Phenotypic Characterization of the Endocannabinoid-Degrading Enzyme Alpha/Beta-Hydrolase Domain 6 Knockout Rat

Introduction: Alpha/beta-hydrolase domain 6 (ABHD6) is an enzyme that hydrolyzes 2-arachidonoylglycerol, a high-efficiency endogenous cannabinoid. Although the endocannabinoid system has been suggested to be involved in regulation of bladder function, the roles of ABHD6 in the control of micturition remain unknown. To elucidate the physiological and pathological roles of ABHD6 in vivo, we examined phenotypes of ABHD6 knockout rats (Abhd6^-/-) generated by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins system. Materials and Methods: Age-matched knockout and wild-type (WT) rats of both sexes were used. Results: Expression of ABHD6, assessed by quantitative real-time polymerase chain reaction and Western blot analysis, was clearly diminished in Abhd6^-/- rats compared with WT rats. Mutant rats had a normal appearance, and the body weight and food consumption were similar to those of WT rats. The interval between bladder contractions assessed by continuous cystometry was significantly shorter in ABHD6 knockout rats than in WT rats when the bladder was stimulated with acetic acid. Mechanical paw withdrawal thresholds measured by von Frey testing were significantly lowered in the knockout rats than in WT rats. The plasma levels of prostaglandin E₂ (PGE₂) and the stable metabolite of PGE₂ in Abhd6^-/- rats were twice as high as that in WT rats. Conclusions: Deletion of the ABHD6 gene in rats causes more frequent urination in the stimulated bladder and hyperalgesia to non-noxious mechanical stimuli along with increased plasma PGE₂.

Purinergic signalling in the urinary tract in health and disease

Purinergic signalling is involved in a number of physiological and pathophysiological activities in the lower urinary tract. In the bladder of laboratory animals there is parasympathetic excitatory cotransmission with the purinergic and cholinergic components being approximately equal, acting via P2X1 and muscarinic receptors, respectively. Purinergic mechanosensory transduction occurs where ATP, released from urothelial cells during distension of bladder and ureter, acts on P2X3 and P2X2/3 receptors on suburothelial sensory nerves to initiate the voiding reflex, via low threshold fibres, and nociception, via high threshold fibres. In human bladder the purinergic component of parasympathetic cotransmission is less than 3 %, but in pathological conditions, such as interstitial cystitis, obstructed and neuropathic bladder, the purinergic component is increased to 40 %. Other pathological conditions of the bladder have been shown to involve purinoceptor-mediated activities, including multiple sclerosis, ischaemia, diabetes, cancer and bacterial infections. In the ureter, P2X7 receptors have been implicated in inflammation and fibrosis. Purinergic therapeutic strategies are being explored that hopefully will be developed and bring benefit and relief to many patients with urinary tract disorders.

Effect of the phytotherapeutic agent eviprostat on the bladder in a rat model of bladder overdistension/emptying

AIMS

Ischemia-reperfusion injury is an important factor in the development of lower urinary tract symptoms (LUTS) that is partly mediated by the generation of free radicals. We investigate the effect of the phytotherapeutic agent Eviprostat, a treatment for benign prostatic hyperplasia (BPH) that has antioxidant and anti-inflammatory activity, on urinary bladder blood flow (BBF), and function in a rat model of bladder overdistension and emptying (OE).

METHODS

For 8 days before surgery, OE rats received daily oral Eviprostat (36 mg/kg/day) or vehicle, while sham-operated animals received vehicle. The bladder was distended by infusion of saline over a period of 2 hr (overdistension) and then emptied. After 24 hr, BBF was measured with a laser speckle blood flow imager. The oxidative-stress marker malondialdehyde (MDA), proinflammatory cytokines, and myeloperoxidase were determined in the isolated bladder, and histological analysis was performed. Functional contractile responses of bladder strips to electrical field stimulation, carbachol, and KCl were measured.

RESULTS

Twenty-four hours after bladder OE, a significant decrease in BBF and significant increases in bladder weight, malondialdehyde, proinflammatory cytokines, and myeloperoxidase were observed. Eviprostat almost completely prevented these changes. Histological analysis of the bladder of OE rats showed hemorrhage, accumulation of leukocytes, desquamation of epithelium, and edema, and Eviprostat suppressed these changes. The reduction in functional contractile forces in the bladder of OE rats was also prevented by Eviprostat.

CONCLUSION

Eviprostat-mediated suppression of increased bladder oxidative stress and inflammation caused by bladder OE may contribute to the improvement of BBF and bladder function by Eviprostat.

Improvement by phytotherapeutic agent of detrusor overactivity, down-regulation of pharmacological receptors and urinary cytokines in rats with cyclophosphamide induced cystitis

PURPOSE

We characterized pharmacological effects of the phytotherapeutic agent Eviprostat® on urodynamic parameters, bladder muscarinic and purinergic receptors, and urinary cytokines in rats with cyclophosphamide induced cystitis.

MATERIALS AND METHODS

Urodynamic parameters in cyclophosphamide (150 mg/kg intraperitoneally) treated rats were measured by a cystometric method. Muscarinic and purinergic receptors in the bladder and other tissues were measured by radioreceptor assays using [N-methyl-(3)H]scopolamine methyl chloride and [(3)H]αβ-MeATP, respectively. The urinary cytokines interleukin-1β, 6 and 17 were measured with enzyme-linked immunoassay kits. Eviprostat (36 mg/kg per day twice daily for 7 days) was orally administered.

RESULTS

On cystometry the micturition interval and micturition volume were significantly decreased in cyclophosphamide vs sham treated rats, while micturition frequency, basal pressure and post-void residual urine volume were significantly increased. Repeat oral administration of Eviprostat in cyclophosphamide treated rats significantly increased the micturition interval and micturition volume, and decreased micturition frequency, basal pressure and post-void residual urine volume. The maximal number of binding sites for [N-methyl-(3)H]scopolamine methyl chloride and [(3)H]αβ-MeATP was significantly decreased in the bladder of cyclophosphamide vs sham treated rats. Such decreases were significantly attenuated by repeat Eviprostat treatment. Increased urinary cytokine levels in cyclophosphamide treated rats were also effectively attenuated by Eviprostat.

CONCLUSIONS

Repeat Eviprostat treatment significantly improved detrusor overactivity, down-regulated the expression of bladder pharmacological receptors and increased urinary cytokine levels in rats with cyclophosphamide induced cystitis. Therefore, Eviprostat may be a pharmacologically useful phytotherapeutic agent for cystitis.

Suppression of bladder overactivity and oxidative stress by the phytotherapeutic agent, Eviprostat, in a rat model of atherosclerosis-induced chronic bladder ischemia

OBJECTIVES

To clarify the mechanism by which chronic bladder ischemia causes bladder functional changes, and to investigate the involvement of oxidative stress and pro-inflammatory cytokines, and the effects of the phytotherapeutic drug, Eviprostat, on these biochemical marker levels and bladder function.

METHODS

Male Sprague-Dawley rats aged 15 weeks were divided into three groups. Arterial injury was experimentally induced by balloon endothelial injury of the iliac arteries, and a 2% cholesterol diet was given for 8 weeks. Rats in the arterial-injury group were given daily oral vehicle or Eviprostat, whereas sham-operated animals on a regular diet (0.09% cholesterol) were given vehicle for the last 2 weeks. Eight weeks after surgery, the levels of bladder pro-inflammatory cytokines, as well as bladder and urinary oxidative-stress markers, were determined. Cystometrograms were carried out without anesthesia or restraint.

RESULTS

Bladder and urinary oxidative-stress markers, and bladder pro-inflammatory cytokine levels were significantly increased in the arterial-injury group, and Eviprostat markedly suppressed these increase. The cystometrograms showed that arterial injury decreased the intermicturition interval without affecting the micturition pressure. This decrease was reversed by Eviprostat treatment.

CONCLUSIONS

Oxidative stress and pro-inflammatory cytokines might be involved in the development of overactive bladder by atherosclerosis-induced chronic bladder ischemia. Eviprostat might provide an attractive treatment option for individuals with bladder dysfunction due to chronic bladder ischemia because of its anti-oxidant and anti-inflammatory properties.

Suppressive Effects of Eviprostat, a Phytotherapeutic Agent, on Lower Urinary Tract Symptoms in Prostate Cancer Patients Treated with Brachytherapy

OBJECTIVES

Eviprostat is an anti-oxidant, anti-inflammatory phytotherapeutic agent that is commonly used to treat lower urinary tract symptoms (LUTS) in benign prostatic hyperplasia in Japan and Germany. Prostate cancer patients treated with brachytherapy generally have complaints of LUTS for several months postoperatively.

METHODS

We investigated the protective effects of Eviprostat against the development of LUTS in 37 patients, who had received (125) I prostate brachytherapy as monotherapy. These patients were divided into two groups, an Eviprostat-treated group (n = 18) and an untreated control (n = 19), whose background had no significant difference. The group treated with Eviprostat was prophylactically medicated from 3 weeks preoperatively until 3 months postoperatively. Symptom scores and quality of life for urination were evaluated according to the International Prostate Symptom Score (IPSS) and Expanded Prostate Cancer Index Composite (EPIC) on preoperative day 1, and postoperative months 1, 3 and 6.

RESULTS

Both the scores of IPSS and the levels of quality of life in EPIC were significantly worse at 1 month postoperatively compared to the pretreatment baseline, and thereafter progressively improved in both groups. Eviprostat-treated patients showed significantly better recovery compared to Eviprostat-untreated control at 6 months postoperatively, with respect to urinary summary score, urinary function and urinary irritation/obstruction subscales in EPIC. Moreover, the feeling of incomplete emptying in IPSS and the urinary irritation/obstruction subscale in EPIC were significantly improved at 3 months postoperatively compared to the peak impairment at 1 month in the Eviprostat-treated group.

CONCLUSIONS

It is possible that Eviprostat has the potential to ameliorate postoperative LUTS caused by brachytherapy.

Effect of a phytotherapeutic agent, Eviprostat®, on prostatic and urinary cytokines/chemokines in a rat model of nonbacterial prostatitis

BACKGROUND

Chronic inflammation in the prostate has recently been recognized as an important component of the symptom progression of benign prostatic hyperplasia. The objective of this study was to evaluate a range of cytokines/chemokines in prostate tissue and urine to identify markers of prostate inflammation in a prostatitis model and to investigate the effect of a phytotherapeutic agent, Eviprostat®, on these markers.

METHODS

Ten-month-old male Wistar rats were divided into four groups. Nonbacterial prostatitis (NBP) was experimentally induced in groups 2-4 by castration followed by daily subcutaneous injection of 17β-estradiol for 30 days. Control rats were fed a standard diet, while animals in the Eviprostat groups were fed a diet containing 0.05 or 0.1% Eviprostat for 30 days. The levels of cytokines/chemokines in prostate tissue on the 31st day and in urine collected the day before castration and the day before removal of the prostate were determined.

RESULTS

Experimentally induced NBP increased the prostatic levels of the cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). The levels of the chemokines CCL2/monocyte chemoattractant protein-1 (MCP-1), CCL3/macrophage inflammatory protein-1α (MIP-1α), CXCL1/CINC-1, CXCL3/CINC-2, and CXCL5/LIX were elevated in both prostate and urine. Eviprostat significantly suppressed the increases in prostate IL-1β, TNF-α and CCL3/MIP-1α and prostatic and urinary CCL2/MCP-1 and CXCL1/CINC-1.

CONCLUSIONS

Chemokines, including CCL2/MCP-1 and CXCL1/CINC-1, were elevated in the prostate and urine of NBP rats, and Eviprostat potently suppressed the increases in CCL2/MCP-1 and CXCL1/CINC-1. These chemokines are therefore candidate diagnostic biomarkers for nonbacterial chronic prostatic inflammation.

Effect of the phytotherapeutic agent Eviprostat on 17beta-estradiol-induced nonbacterial inflammation in the rat prostate

BACKGROUND

Anti-inflammatory medications have been used for the treatment of chronic prostatitis. The phytotherapeutic agent Eviprostat, a popular treatment for benign prostatic hyperplasia in Japan and Germany, has antioxidant and anti-inflammatory activity. We investigated the effects of the phytotherapeutic agent Eviprostat on prostate inflammation induced in castrated rats by the injection of 17beta-estradiol.

METHODS

Ten-month-old male Wistar rats were divided into five groups. Nonbacterial prostatitis was experimentally induced in groups 2-5 by castration followed by daily subcutaneous injection of 17beta-estradiol for 30 days. The rats were orally administered 0.1% Tween-80 (group 2), low-dose Eviprostat (group 3), high-dose Eviprostat (group 4), or cernitin pollen extract (group 5) for the last 2 weeks of 17beta-estradiol administration. Sham-operated rats (group 1) were orally administered 0.1% Tween-80. On the 31st day after surgery, the weight of the prostate and the levels of prostatic proinflammatory cytokines as well as the oxidative-stress marker malondialdehyde were determined and histological alterations noted.

RESULTS

Experimentally induced nonbacterial prostatitis led to a significant decrease in prostate weight and increases in malondialdehyde and proinflammatory cytokine levels. Eviprostat significantly suppressed the increases in malondialdehyde and cytokine levels without affecting prostate weight. Histologically, nonbacterial prostatitis was evident in the lateral lobe of the prostate, and Eviprostat treatment significantly suppressed the severity of the lesion.

CONCLUSIONS

Eviprostat, which has effective antioxidant and anti-inflammatory activities in the prostate, may be useful for the clinical treatment of chronic prostatitis. These activities of Eviprostat may also contribute to the amelioration of prostate inflammation in BPH patients. Prostate 69: 1404-1410, 2009. (c) 2009 Wiley-Liss, Inc.

Suppression of bladder oxidative stress and inflammation by a phytotherapeutic agent in a rat model of partial bladder outlet obstruction

PURPOSE

Ischemia/reperfusion injury is a major etiological factor in the progression of bladder dysfunction after partial bladder outlet obstruction and it is partly mediated by the generation of free radicals. The phytotherapeutic agent Eviprostat, a popular treatment for benign prostatic hyperplasia in Japan and Germany, has antioxidant and anti-inflammatory activity. We investigated the effect of Eviprostat on oxidative stress and inflammation in bladder dysfunction in a bladder outlet obstruction rat model.

MATERIALS AND METHODS

Bladder outlet obstruction was surgically induced in male rats by placing a rubber ring around the urethra. Rats with bladder outlet obstruction were administered daily oral Eviprostat or vehicle, while sham operated animals were treated with vehicle. On day 6 after surgery bladder weight, oxidative stress markers and proinflammatory cytokine levels as a measure of bladder inflammation, were determined and histological alterations noted. Functional contractility studies were performed with longitudinal bladder strips.

RESULTS

Bladder outlet obstruction led to a significant increase in bladder weight, oxidative stress markers and proinflammatory cytokine levels. Eviprostat significantly suppressed these increases without affecting bladder weight. Histological analysis showed increased detrusor muscle hypertrophy and increased numbers of collagen fibers with accompanying inflammatory infiltration in the bladder of vehicle treated bladder outlet obstruction animals. Eviprostat treatment was associated with suppression of these changes. Decreased responses of obstructed bladder strips to electrical stimulation and KCl were ameliorated by Eviprostat treatment.

CONCLUSIONS

Eviprostat mediated decrease of the increased oxidative stress and bladder inflammation caused by bladder outlet obstruction may contribute to the protection of bladder function.