Phosphodiesterase 5 Inhibitors Attenuate Unilateral Ureteral Obstruction-Induced Renal Fibrosis / 中山大学学报(医学科学版)

ObjectiveTo investigate whether phosphodiesterase （PDE） 5 inhibitors sildenafil （SIL） or LW1646 prevented renal interstitial fibrosis induced by unilateral ureteral obstruction （UUO）. MethodsMale C57BL/6 mice were randomly divided into four groups （n =6）， namely the Sham group， 7UUO group， 7UUO+SIL group and 7UUO+LW1646 group. Sildenafil （SIL） or LW1646， or vehicle was administered 1 hour before surgery， and the mice were continuously treated once daily （i. g.， 50 mg/kg） for 7 days. The obstructed kidneys were harvested on day 7. Hematoxylin-eosin （HE） and Masson’s staining was used to examine renal histology. Immunoblotting and RT-qPCR were used to detect the expression levels of protein and mRNA for fibrosis， apoptosis， endoplasmic reticulum （ER） stress， autophagy， and pro-fibrotic factors. Human proximal tubule epithelial cells （HK-2） were treated with TGF-β1 for 48 hours or tunicamycin for 24 hours， respectively， to evaluate whether cyclic guanosine monophosphate （cGMP） or PDE5 inhibitors prevents ER stress and pro-fibrotic responses. ResultsAt the 7th days after UUO， the body weight of the mice showed a significant decrease （P< 0.000 1） compared with that in the sham group. The obstructed kidneys showed a significant tubular dilation and interstitial inflammation. The levels of protein and mRNA expression in apoptosis， ER stress， autophagy-related protein and pro-fibrotic factors were also markedly increased in UUO mice （P <0.05）. In contrast， SIL or LW1646 treatment was associated with attenuated tubular dilation， infiltration of inflammatory cells and collagen content in the obstructed kidney of the mice. The protein and mRNA expression levels of renal TGF-β1 were markedly decreased， and the protein expression levels of apoptosis， endoplasmic reticulum stress， and autophagy markers were also significantly downregulated by PDE5 inhibitors. In HK-2 cells， TGF-β1 induced increased expression levels of fibronectin and BiP， which was at least partially reversed by cGMP， a product of PDE inhibition. Additionally， PDE5 inhibitors were found to modulate aberrant levels of autophagy and apoptosis. ConclusionIn conclusion， PDE5 inhibitors， in particular， LW1646， can alleviate the progression of fibrosis by improving ER stress， apoptosis and autophagy as well as downregulating protein and mRNA expression of TGF-β1.

A Case of Central Serous Chorioretinopathy after Tadalafil Treatment

PURPOSE: To describe a patient who presented with central serous chorioretinopathy after 2 months of tadalafil administration without any other underlying disease or medication. CASE SUMMARY: A 49-year-old male patient was transferred from a local clinic with metamorphopsia and decreased visual acuity in the right eye. His visual acuity was 6/20 in the right eye and 18/20 in the left eye. The fundus examination showed a large serous detachment between the superior and inferior blood vessel arcades in the right retina. In his medical history, he used tadalafil three times a week for 2 months. His medication was then stopped, and a follow-up examination was scheduled. After 2 months, a fundus examination showed resolution of the subretinal fluid, and his corrected visual acuity recovered to 20/20. CONCLUSIONS: Tadalafil (Cialis®) is a phosphodiesterase (PDE)-5 inhibitor and predominantly prescribed for the treatment of erectile dysfunction. PDE–5 inhibitors may be potent vasodilators in the retina and choroid, and may induce choroidal vessel engorgement leading to leakage across the retinal pigment epithelium and accumulation of subretinal fluid in selected patients. When making a diagnosis as central serous chorioretinopathy, the physician should confirm the causative drugs that are easy to miss, by performing a thorough review of the patient's medical history and promptly terminating the causative drugs.

Effects of mirodenafil on the hemodynamics in hypertensive patients taking amlodipine

While phosphodiesterase type 5 inhibitors have been used for erectile dysfunction with acceptable safety profile, they can induce orthostatic hypotension in patients taking antihypertensive drugs with blood pressure lowering effect. This study evaluated the hemodynamic effects of 100 mg mirodenafil in hypertensive patients taking an amlodipine. Thirteen hypertensive patients who were taking 5 or 10 mg of amlodipine once daily participated in a randomized, double-blind, placebo-controlled, crossover study. A single oral dose of mirodenafil 100 mg or placebo was administered at 4.5 hour after administration of amlodipine. The maximal change in systolic and diastolic blood pressure (ΔmaxSBP and ΔmaxDBP) and pulse rate (ΔmaxPR) were compared between mirodenafil and placebo periods. Twelve patients completed this study and were included analysis. The values of ΔmaxPR in standing and supine position were significantly greater in the mirodenafil period (13.25±7.12 and 11.17±4.86 beats/minute) when compared to the placebo (8.50±4.72 and 6.58±3.90 beats/minute). The ΔmaxSBP and ΔmaxDBP in standing position appeared to be lower in the mirodenafil period, but they were not statistically different from those in the placebo period (ΔmaxSBP = -7.42±5.6 vs -4.42±5.37 mmHg and ΔmaxDBP = -7.17±5.72 vs -3.50±3.37 mmHg). Both ΔmaxSBP and ΔmaxDBP in standing and supine position were not significantly different between mirodenafil and placebo. This study demonstrated that mirodenafil exerted minimal hemodynamic effects in the patients taking amlodipine, that is unlikely associated with a clinically significant hypotensive event.

Qualitative and quantitative analysis of 31 PDE-5 inhibitors in herbal products and dietary supplements by UPLC/Q-TOF-MS / 中国药学杂志

OBJECTIVE: To develop an applicable approach to rapidly analyze 31 PDE-5 inhibitors qualitatively and quantitatively and provide a strategy for detection and rapid identification of similar derivatives in herbal products and dietary supplements based on high-resolution quadrupole-time-of-flight mass spectrometry (Q-TOF-MS). METHODS: The analysis was performed on an Agilent ZORBAX RRHD Eclipse Plus C18 column with the mixture of 0.1% formic acid-acetonitrile-water as mobile phase, and the flow rate was 0.4 mL · min. Q-TOF-MS equipped with ESI ion source was performed in positive ionization mode. Qualitative analysis was based on the accurate mass, the elemental compositions and the product ions. Quantitative analysis was performed by using the peak area and concentration of each compound. RESULTS: The ESI-MS fragmentation behaviors of three common structural skeletons (sildenafil, vardenafil, and tadalafiland) were characterized and summarized. Good linearity was obtanined in the ranges of 1-200, 5-400 or 20-600 ng · mL-1 for the calibration curves of the 31 analytes(r≥0.9974). The LOQs were 0.07-37.82 pg, recoveries were 75.00%-124.56%, and RSDs were less than 7.56% (n=6). CONCLUSION: The established method is simple, accurate and reliable. It is suitable for determining PDE-5 inhibitors and rapid detection of similar derivatives in herbal products and dietary supplements.

Synthesis and phosphodiesterase type-5 inhibitory activity of sildenafil analogues possessing a guanidine group in the phenyl ring / 中国药科大学学报

In this study,a series of new sildenafil analogues 11-27 possessing a guanidine group were synthesized to investigate their PDE5 inhibitory activity and selectivity using[~3H]cGMP SPA kit in vitro and efficacy in the rat model of erection.Most of the compounds showed potent activity against PDE5,and more importantly,several compounds exhibited higher PDE5 selectivity over PDE6 than that of sildenafil.Structure-activity relationship of these sildenafil analogues was also discussed.Within this series of compounds,compound 15(IC_(50) =1.7 nmol/L)not only exhibited more potent PDE5 inhibitory activity than that of sildenafil (IC_(50) = 6.5 nmol/L),but also showed functional efficacy in the rat model of erection.

The effect of vardenafil, a new potent highly selective phosphodiesterase type 5 inhibitor in the treatment of erectile dysfunction / 中华泌尿外科杂志

Objective To investigate the safety and efficacy of vardenafil,a novel selective phosphodiesterase type 5 inhibitor, in the treatment of male erectile dysfunction (ED). Methods This multicenter,randomized,double blind,placebo controlled study was performed at 7 domestic sites.A total of 624 men with mild to severe ED were enrolled in this trial of 4 weeks of washout and 12 weeks of treatment with either placebo or 5,10,20 mg of vardenafil on demand but not more than once a day. Results Analysis of safety and efficacy of vardenafil was performed on 602 cases who completed the trial.Primary endpoints were Q3 (vaginal penetration) and Q4 (maintenance of erection) of the International Index of Erectile Function (IIEF).In the intent to treat population (n=602),the changes from baseline with 5,10,20 mg vardenafil groups were all improved ( P