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 Review on the Pharmacological Importance of PDE5 and Its Inhibition to Manage Biomedical Conditions

Phosphodiesterase type 5 (PDE5) is a cyclic GMP (cGMP) specific protein. It hydrolyzes the phosphodiesterase linkage and catalyzes the conversion of cGMP to 5’ GMP, which controls different physiological activities of the body. PDE5 is associated with biomedical conditions like neurological disorders, pulmonary arterial hypertension, cardiomyopathy, cancer, erectile dysfunction, and lower urinary tract syndrome. Inhibition of PDE5 has now been proven pharmaceutically effective in a variety of therapeutic conditions. Avanafil, tadalafil, sildenafil, and vardenafil are the most commonly used PDE5 inhibitors (PDE5i) today which are often used for the management of erectile dysfunction, lower urinary tract syndromes, malignancy, and pulmonary arterial hypertension. However, these synthetic PDE5i come with a slew of negative effects. Some of the most common side effects include mild headaches, flushing, dyspepsia, altered color vision, back discomfort, priapism, melanoma, hypotension and dizziness, non-arteritic anterior ischemic optic neuropathy (NAION), and hearing loss. In light of the potential negative effects of this class of medications, there is a lot of room for new, selective PDE5 inhibitors to be discovered. We have found 25 plant botanical compounds effectively inhibiting PDE5 which might be useful in treating a variety of disorders with minimal or no adverse effects.

Identification And Quantification Of Phosphodiesterase-5 Inhibitors As Adulterants In Dietary Supplements Marked For Sexual Enhancement In The Lebanese Market

Objective: Ultraviolet Visible spectrophotometric was adopted to identify and quantify any adulteration with PDE-5 inhibitors (Sildenafil and Tadalafil) in selected dietary supplements used for sexual enhancement in the Lebanese market Methods: Nine dietary supplements, randomly collected from Lebanese pharmacies, were screened for Sildenafil and Tadalafil using UV-spectrophotometry for both qualitative and quantitative detection. Results: Tadalafil was detected in one sample at a dose of 59 mg/dosage unit, with the maximal recommended dose being 20 mg. Sildenafil was detected in five samples at doses ranging from 11.7 to 188.2 mg/dosage unit, with the maximal recommended dose being 100 mg. Conclusion: This study demonstrates that regular analysis of supposed dietary supplements is needed for more effective quality control and health promotion. The method described for the extraction, identification and quantification of Tadalafil and Sildenafil would be useful for regulatory detection of adulterations.

Discovery and identification of a tadalafil analogue / 药学学报

A tadalafil analogue was detected during routine screenings from two "fatigue reliever, immunity enhancer" dietary supplements by using UHPLC/Q-TOF HRMS. The MS2 spectrum of this compound was almost identical to that of 2-hydroxypropylnortadalafil. However, the retention time of this analogue was different from that of the 2-hydroxypropylnortadalafil isomers. The analogue was purified by using preparative HPLC and the structure was elucidated by mass spectrometric and NMR spectroscopic experiments. The spectral data suggested that the analogue bore a 3-hydroxypropyl group instead of the N-methyl group in tadalafil. The structure was further confirmed by comparison of the 1H NMR spectra data with those of the reference standard, and thus named as 3-hydroxypropylnortadalafil. The structure is first reported in China.

The Effect of Tadalafil on Renal Fibrosis Induced by Ureteral Obstruction / Efecto del Tadalafil en la Fibrosis Renal Inducida por Obstrucción Uretral

ABSTRACT Objective: It has been reported that phosphodiesterase-5 (PDE-5) inhibitors improve kidney function during acute and chronic renal failure. This study aimed to determine the possible therapeutic effects of tadalafil, a specific PDE-5 inhibitor, on renal fibrosis induced by unilateral ureteral obstruction (UUO). Methods: Male Sprague-Dawley rats were used and randomly divided into three groups (n = 6) as sham-operated, UUO and tadalafil-treated (10 mg/72 hours, ig) UUO (UUO+T) groups. Unilateral ureteral obstruction was induced by complete ligation of the left ureter and 14 days after surgery creatinine clearance, urinary cyclic guanosine monophosphate (cGMP), renal alpha-smooth muscle actin (α-sma) and transforming growth factor βeta (TGF-β) levels, as well as histologic changes, were observed in all the animals. Results: Unilateral ureteral obstruction-induced renal fibrosis was confirmed by increased α-sma level, collagen deposition, tubular dilation, inflammatory cell infiltration and necrosis. An increased renal TGF-β level and decreased urinary cGMP level was also observed in obstructed animals in addition to reduced creatinine clearance. Tadalafil treatment, which restored the animals 'urinary cGMP level, significantly attenuated the fibrotic changes and TGF-β increase in their kidneys. Conclusion: This study suggests that tadalafil treatment ameliorates renal fibrosis by reducing TGF-β expression and may have important clinical relevance since tadalafil is currently used clinically to treat erectile dysfunction and pulmonary hypertension.

RESUMEN Objetivo: Se ha reportado que los inhibidores de la fosfodiesterasa-5 (PDE-5) mejoran las funciones renales durante la insuficiencia renal aguda y crónica. Este estudio tuvo por objetivo determinar los posibles efectos terapéuticos del tadalafil - un inhibidor específico de la PDE-5 - sobre la fibrosis renal inducida por una obstrucción ureteral unilateral (OUU). Métodos: Se utilizaron ratas machos Sprague-Dawley, divididas de manera aleatoria en tres grupos (n = 6): operación simulada, OUU y tratamiento con tadalafil (10 mg/72 horas, IG), y OUU (OUU+T). La obstrucción uretral unilateral fue inducida por una ligadura completa del uréter izquierdo y 14 días después de la cirugía, se observaron niveles de monofosfato de guanosina cíclico (GMP) urinario, alfa-actina de músculo liso (α-SMA), y factor de crecimiento transformante βeta (FCT-β), así como cambios histológicos en todos los animales. Resultados: La fibrosis renal inducida por obstrucción uretral unilateral fue confirmada por un aumento del nivel de α-SMA, deposición de colágeno, dilatación tubular, infiltración de células inflamatorias y necrosis. También se observó un aumento del nivel de FCT-β renal y una disminución del nivel de GMP urinario en los animales con obstrucción, además de una reducción del aclaramiento de la creatinina. El tratamiento con tadalafil, que restauró el nivel de GMP urinario de los animales, atenuó significativamente los cambios fibróticos y el aumento de FCT-β en los riñones. Conclusión: Este estudio sugiere que el tratamiento con tadalafil mejora la fibrosis renal al reducir la expresión de FCT-β y puede tener una importante relevancia clínica por cuanto el tadalafil se usa hoy día clínicamente para tratar la disfunción eréctil y la hipertensión pulmonar.

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 Schisandra chinensis fruit extract and gomisin A on the contractility of penile corpus cavernosum smooth muscle: a potential mechanism through the nitric oxide - cyclic guanosine monophosphate pathway

BACKGROUND/OBJECTIVES: This study evaluated the effects and molecular mechanisms of the Schisandra chinensis fruit extract (SC) and its major compound gomisin A (GA), on the contractility of rabbit penile corpus cavernosum smooth muscle (PCCSM). MATERIALS/METHODS: PCCSM was exposed to SC or GA after appropriate pretreatment with nitric oxide synthase (NOS) blocker, guanylate cyclase blocker, adenylyl cyclase blocker or protein kinase A blocker. Subsequently, we evaluated the cyclic nucleotide in the perfusate by radioimmunoassay, protein expression level of neuronal NOS (nNOS) and endothelial NOS (eNOS) by western blot, and the interaction of SC or GA with udenafil and rolipram. RESULTS: Both SC and GA induce PCCSM relaxations in a concentration-dependent manner. Pretreatment with NOS blocker, guanylate cyclase blocker, adenylyl cyclase blocker or protein kinase A blocker result in significantly decreased relaxation. SC and GA also induce the levels of cyclic nucleotide in the perfusate in a concentration-dependent manner. Perfusion with GA also showed significantly higher levels of eNOS protein. Furthermore, the udenafil and rolipram induced relaxations of PCCSM were enhanced after exposure to SC and GA. Our results indicate that SC and GA induce the relaxation of PCCSM via the nitric oxide (NO)-cGMP and cAMP signaling pathways. CONCLUSIONS: The SC and GA are potential alternative treatments for men who want to consume natural products to ameliorate erectile function, or who do not respond to the commercially available medicines.

Spectrum-effect relationship of inhibition of different extracted parts from Lepdium meyenii on PDE5 activity / 中草药

Objective: To clarify the contribution of inhibitory effect of the chemical composition of fingerprint characteristic peaks from different parts of Lepdium meyenii (Maca) on PDE5, and to elucidate the material basis. Methods: The HPLC fingerprints of different parts from L. meyenii were established. The isotope labelling method was adopted to test the inhibitory rate of different extracted parts on PDE5.The gray relative analysis and partial least-squares method were used to make correspond analysis of the spectrum-effect relationship. Results: The fingerprints of different extracts were established and five peaks of the total 21 characteristic common peaks were identified by HPLC spectrum of standards and LCMS-IT-TOF. The strong relevance elements including macamide alkaloids represented by peaks 22-24 were verified as the potential PDE5 inhibitors. Conclusion: A sensitive and convenient screening system for the PDE5 inhibitors via liquid scintillation counting is established. Macamides as liposoluble alkaloids could be material basis components to inhibit the activity of PDE5.This paper provides certain theory basis for resource utilization and the quality control of L. meyenii.

High Doses of PDE5 inhibitors and tramadol reversibly alters haematological parameters in rats.

This study examined the effect of chronic administration of PDE5 inhibitors and tramadol on haematological indices because of their reported high incidence of abuse. Additionally, the possibility of reversal of negative effects following withdrawal of treatment was examined. Fifty male rats (180 - 200g body weight) were grouped into five (n = 10), namely: control, sildenafil, tadalafil, tramadol and sildenafil+tramadol group. The different groups were orally treated with 0.2mL normal saline, sildenafil (1 mg/100gb.w.), tadalafil (1 mg/100gb.w.), tramadol (2 mg/100g b.w.) and sildenafil + tramadol (1 &2 mg/100gb.w. respectively). Treatment was done thrice a week, for 8 weeks and the animals were allowed access to feed and water ad libitum. Five animals were sacrificed per group, while the remaining 5/group continued for another 8 weeks without drug administration (recovery test).Blood samples were collected from each animal via cardiac puncture at the end of both phases for assessment of haematological parameters. Red blood cells (RBC) count, haemoglobin (Hb) concentration, packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), red cell distribution wide standard deviation (RDW-SD), white blood cells (WBCs) count, platelets count, mean platelets volume (MPV) and platelets large cell ratio (P-LCR) were significantly reduced in all the treated groups compared with the control. Following withdrawal of treatment, RBC count, Hb concentration, PCV and red cell absolute values were significantly increased in all recovery groups compared with their respective treated groups. Haematological alterations were reversed following withdrawal of treatment. However, platelet indices were poorly reversed in sildenafil and tramadol recovery groups.

Effectiveness and Safety of PDE5 Inhibitors for Men with Erectile Dysfunction Caused by Spinal Cord Injury.

Aims: The objective of this review was to assess the effectiveness of phosphodiesterase type 5 (PDE5) inhibitors in men with erectile dysfunction (ED) and spinal cord injury (SCI). Methodology: The following databases were sought up to May 2015: PubMed, Google scholar, EMBASE and Cochrane Library. We performed a meta-analysis of all available randomised controlled trials. We used odds ratios (ORs) to assess the strength of the association, and 95% confidence intervals (CIs) gave a sense of the precision of the estimate. Statistical analyses were performed by Review Manager, version 5.0. Results: After searching and screening the relevant articles, ten studies were included and assessed the effectiveness of PDE5 inhibitors in men with erectile dysfunction and spinal cord injury. The pooled results showed that sildenafil significantly improved erection compared with placebo in ED patients with SCI (OR = 5.96, 95% CI [3.36–10.55], P ＜ 0.00001) and there was no statistical difference compared incomplete injury group with complete injury group (OR = 0.73, 95% CI [0.38–1.43], P=0.36). It is evident that compared upper motor neuron with lower motor neuron, there were better responsive rates in sildenafil(OR = 11.56, 95% CI [2.88–46.36], P=0.0006). Because of lacking studies and data, we could not perform meta-analysis for other PDE5 inhibitors. The commonly reported adverse effects (AEs) were headache, flushing, dizziness and urinary tract infection in these studies. No severe adverse events were found. Conclusion: Current evidence suggests that sildenafil is effective treatment for ED patients with SCI. In future, we need more high quality randomized controlled trials (RCTs) to confirm these findings and evaluate the effectiveness of other PDE5 inhibitors.

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.

The effects of vardenafil and pentoxifylline administration in an animal model of ischemic colitis

OBJECTIVES: Vardenafil enhances dilatation of vascular smooth muscle and inhibits platelet aggregation. The purpose of this study was to evaluate the clinical effects of vardenafil and pentoxifylline administration in an experimental model of ischemic colitis. METHODS: Forty female Wistar albino rats weighing 250-300 g were randomized into five experimental groups (each with n = 8) as follows:1) a sham group subjected to a sham surgical procedure and administered only tap water; 2) a control group subjected to a standardized surgical procedure to induce ischemic colitis and administered only tap water; 3) and 4) treatment groups subjected to surgical induction of ischemic colitis followed by the postoperative administration of 5 mg/kg or 10 mg/kg vardenafil, respectively; and 5) a treatment group subjected to surgical induction of ischemic colitis followed by postoperative administration of pentoxifylline at 50 mg/kg/day per day as a single dose for a 3-day period. All animals were sacrificed at 72 h post-surgery and subjected to relaparotomy. We scored the macroscopically visible damage, measured the ischemic area and scored histopathology to determine the severity of ischemia. Tissue malondialdehyde levels were also quantified. RESULTS: The mean Gomella ischemic areas were 63.3 mm2 in the control group; 3.4 and 9.6 mm2 in the vardenafil 5 and vardenafil 10 groups, respectively; and 3.4 mm2 in the pentoxifylline group (p = 0.0001). The mean malondialdehyde values were 63.7 nmol/g in the control group; 25.3 and 25.6 nmol/g in the vardenafil 5 and vardenafil 10 groups, respectively; and 22.8 nmol/g in the pentoxifylline group (p = 0.0001). CONCLUSION: Our findings indicate that vardenafil and pentoxifylline are effective treatment options in an animal model of ischemic colitis. The positive clinical effects produced by these drugs are likely due to their influence on the hemodynamics associated ...

Estudo clínico fase I de carbonato de lodenafila, um novo tipo de inibidor de fosfodiesterase 5 (PDE5), em voluntários saudáveis do sexo masculino / A phase I clinical trial of lodenafil carbonate, a new phosphodiesterase type 5 (PDE5) inhibitor, in healthy male volunteers

Carbonato de Lodenafila é um novo tipo de inibidor de fosfodiesterase 5 (PDE5) utilizado no tratamento da disfunção erétil. O presente estudo foi realizado para avaliar a segurança, tolerabilidade e farmacocinética do carbonato de lodenafila após a administração de doses orais únicas ascendentes (de 1 a 100 mg) a voluntários saudáveis do sexo masculino (n = 33). O estudo foi um estudo clínico fase I, aberto, de escalonamento de dose, utilizando a administração de doses orais únicas de carbonato de lodenafila. Carbonato de Lodenafila foi administrado sequencialmente escalonado em doses únicas de 1 mg a 100 mg com um período sem uso do medicamento (washout) de pelo menos 1 semana, entre cada dose. A progressão para a próxima dose foi permitida se após a avaliação dos exames clínicos, laboratoriais e Monitorização Ambulatorial da Pressão Arterial (MAPA), não demonstrassem alterações e eventos adversos sem relevância clínica. As amostras de sangue foram coletadas na pré-dose e em intervalos determinados e 24 horas após a administração. As amostras de plasma para a mensuração de carbonato lodenafila e lodenafila foram analisadas por cromatografia líquida acoplada à espectrometria de massa. Não foram observados eventos adversos graves, e nenhum dos voluntários abandonou o estudo devido à intolerância. As medições do MAPA, exames clínicos e laboratoriais e ECG não revelaram alterações significativas mesmo em doses mais elevadas. Carbonato Lodenafila não foi detectado em qualquer amostra, indicando que ele atua como um pró-droga. Os parâmetros farmacocinéticos médios de lodenafila para tmax e t1 / 2 foram 1,6 (± 0,4) horas e 3,3 (± 1,1) horas, respectivamente. Este estudo demonstrou que o carbonato de lodenafila é bem tolerado e apresentou um bom perfil de segurança em voluntários saudáveis do sexo masculino.

Lodenafil carbonate is a new phosphodiesterase type 5 (PDE5) inhibitor used in treatment of erectile dysfunction. The present study was conducted to evaluate the safety, tolerability, and pharmacokinetics of lodenafil carbonate after administering ascending (1 to 100 mg) single oral doses to healthy male volunteers (n=33). The study was an open-label, dose-escalation, phase I clinical trial involving the administration of single oral doses of lodenafil carbonate. Lodenafil carbonate was administered sequentially, escalating in single doses of 1 mg to 100 mg with a washout period of at least 1 week between each dose. The progression to the next dose was allowed after clinical and laboratory exams, Ambulatory Monitoring of Arterial Pressure (AMAP) without relevant clinical modifications and adverse events without clinical relevancy. Blood samples were collected at pre-dose, determined intervals and 24h postdosing. Plasma samples for measurement of lodenafil carbonate and lodenafil were analyzed by liquid chromatography coupled to tandem mass spectrometry. No serious adverse events were observed, and none of the subjects discontinued the study due to intolerance. The AMAP measurements, clinical and laboratory exams and ECG revealed no significant changes even at higher doses. Lodenafil carbonate was not detected in any samples, indicating that it acts as a pro-drug. The mean lodenafil pharmacokinetic parameters for tmax and t1/2 were 1.6 (±0.4) hr and 3.3 (±1.1) hr, respectively. This study demonstrated that lodenafil carbonate was well tolerated and showed a good safety profile in healthy male volunteers.

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.

Role of Phosphodiesterase Type 5 Inhibitor on Benign Prostatic Hyperplasia/Lower Urinary Tract Symptoms / 대한남성과학회지

There is strong evidence from multiple epidemiological studies that benign prostate hyperplasia (BPH) induced lower urinary tract symptoms (LUTS) are correlated with erectile dysfunction (ED). Although a direct causal relationship is not established yet, four pathophysiological mechanisms can explain the relationship. These include alteration in activity of nitric oxide (NO)-cyclic GMP signal pathway, autonomic hyperactivity, increased Rho kinase/Rho A pathway and pelvic atherosclerosis. Androgens have been suggested to have an important role in the maintenance of the functional and structural integrity of the urinary tract. Sexual function should be assessed and discussed with the patient when choosing the appropriate management strategy for LUTS, as well as when evaluating the patient's response to treatment. Multiple large clinical trials have shown an improvement in LUTS after phosphodiesterase-5 (PDE5)-inhibitor treatment. Sildenafil is a pioneer of this clinical trial and appears to improve both erectile function and LUTS in subjects with ED. Basically PDE5 I with long half life is an appropriate candidate, therefore tadalafil and undenafil had been used to evaluate both diseases. Placebo-controlled trials of tadalafil showed improvement of LUTS secondary to BPH, but none of the studies showed a significant effect on urodynamic measures. PDE5 Is, such as sildenafil and tadalafil, increase the concentration of cGMP in plasma and smooth muscle, facilitating erection of the penis, relaxation of the bladder neck and prostate and subsequent bladder emptying. And theses PDE5 Is increase cAMP and cGMP levels and are more highly distributed in the prostate than plasma. These findings may help in the assessment of the feasibility of using PDE5 Is to concurrently treat both LUTS and ED.

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.

Effect of Benfotiamine on the Expression of Phosphodiesterase Type 5 and Its Isoforms in Type 2 Diabetic Rat Kidneys / 대한남성과학회지

PURPOSE: The phosphodiesterases (PDEs) are critical components in the cyclic AMP/protein kinase A and the cyclic GMP/phosphokinase G signaling pathways. The cAMP and cGMP pathways are regulated by activation and dissolution of PDEs. Benfotiamine, a lipophilic derivation of thiamine is known an activator of transketolase, is reported to prevent diabetic nephropathy by decreasing proteinuria and reducing oxidative stress. We did this study to investigate the effect of benfotiamine in type 2 diabetic rat kidneys. MATERIALS AND METHODS: We prepared 10 male Long-Evans Tokushima Fatty (LETO: control) and 20 male Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which developed non-insulin-dependent diabetes mellitus (NIDDM) naturally. An oral glucose tolerance test confirmed diabetic development in the OLETF rats at 26 weeks. We classified 10 of the OLETF rats into Group I, the no treatment group and the other 10 into Group II, the treatment group. Group II received 100 mg/kg benfotiamine after developing DM. At 44 weeks, we checked kidney weight, serum glucose, free testosterone, insulin, total cholesterol, and triglyceride before sacrifice. We designed the primers for rat PDE5, PDE5A1, and PDE5A2 genes were carried out semiquantitive multiplex RT-PCR. Immunohistochemical staining was performed for monoclonal mouse anti-cGB-PDE5 and mouse monoclonal anti-smooth muscle alpha-actin. RESULTS: For the Control Group, Group I, and Group II, kidney weight was 2.13+/-0.23, 2.08+/-0.22, and 1.94+/-0.44 g; serum glucose was 279.50+/-56.79, 338.00+/-55.00, and 314.71+/-139.1 mg/dl; free testosterone was 1.46+/-1.08, 1.05+/- 0.42, and 0.72+/-0.56 pg/dl; insulin was 1.03+/-0.43, 1.09+/-0.83, and 1.15+/-1.08 ng/ml; total cholesterol was 86.83+/-4.79, 132.00+/-7.69, and 118.14+/-30.93 mg/dl; and triglyceride was 78.83+/-16.47, 177.83+/-75.62, and 194.57+/-92.57 mg/dl, respectively. All three groups expressed PDE5, PDE5A1, PDE5A2 mRNA, but Group I PDE5 mRNA expression was lower than that of Group C, II. However, the expression of PDE5A1 and PDE5A2 mRNA was not significantly different among the three groups. CONCLUSIONS: Serum cholesterol, triglyceride, and glucose were significantly higher in OLETF than in LETO rats. The PDEs were lower in diabetic rat (OLETF) kidneys and PDEs may play a significant role in the development of diabetic renal complications. Benfotiamine is suggested to increase expression of PDE5 mRNA in the type 2 diabetes rat kidney, but the difference in expression levels between PDE5A1 and PDE5A2 was not significant. These findings suggest that benfotiamine may play a specific role in diabetic changes of the rat kidney via a PDE5-related pathway, but it is not clear whether subtype PDE5A1 and PDE5A2 genes play a specific role.

Expression Changes of the Phosphodiesterase 5 isoform in the Penis of Type 2 Diabetic Rat / 대한남성과학회지

PURPOSE: To investigate the tissue distribution of PDE5 isoforms in type 2 diabetic rat penile tissues. MATERIALS AND METHODS: We prepared ten male Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which develop NIDDM naturally, and ten control male Long-Evans Tokushima Fatty (LETO) rats. An oral glucose tolerance test confirmed diabetes development in OLETF rats at 26 weeks. At 42 weeks, we checked serum glucose, testosterone, triglyceride, insulin, and adiponectin before sacrifice. We performed semi-quantitative multiplex RT-PCR for rat PDE5, PDE5A1, and PDE5A2. Immunohistochemistry was performed using mouse monoclonal anti-cGB-PDE5 and anti-smooth muscle alpha-actin. RESULTS: OLETF rats were significantly more hyperglycemic, hypogonadal, hyperinsulinemic, hypercholesterolemic, hypertriglycemic, and had lower adiponectin levels than LETO rats. Levels of PDE5 mRNA were decreased in OLETF rats, but there were no changes in PDE5A1 or PDE5A2 mRNA levels. CONCLUSION: Diabetes may contribute to decreased expression of PDE5 mRNA, but not PDE5A1 or PDE5A2, in rat penile tissue. Furthermore, serum free testosterone was decreased in diabetic rats. PDE5 has an important role in the development of diabetic erectile dysfunction, but it is not clear whether PDE5A1 and PDE5A2 gene have specific roles.

Expression Changes of the Phosphodiesterase 5 isoform in the Penis of Type 2 Diabetic Rat / 대한남성과학회지

PURPOSE: To investigate the tissue distribution of PDE5 isoforms in type 2 diabetic rat penile tissues. MATERIALS AND METHODS: We prepared ten male Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which develop NIDDM naturally, and ten control male Long-Evans Tokushima Fatty (LETO) rats. An oral glucose tolerance test confirmed diabetes development in OLETF rats at 26 weeks. At 42 weeks, we checked serum glucose, testosterone, triglyceride, insulin, and adiponectin before sacrifice. We performed semi-quantitative multiplex RT-PCR for rat PDE5, PDE5A1, and PDE5A2. Immunohistochemistry was performed using mouse monoclonal anti-cGB-PDE5 and anti-smooth muscle alpha-actin. RESULTS: OLETF rats were significantly more hyperglycemic, hypogonadal, hyperinsulinemic, hypercholesterolemic, hypertriglycemic, and had lower adiponectin levels than LETO rats. Levels of PDE5 mRNA were decreased in OLETF rats, but there were no changes in PDE5A1 or PDE5A2 mRNA levels. CONCLUSION: Diabetes may contribute to decreased expression of PDE5 mRNA, but not PDE5A1 or PDE5A2, in rat penile tissue. Furthermore, serum free testosterone was decreased in diabetic rats. PDE5 has an important role in the development of diabetic erectile dysfunction, but it is not clear whether PDE5A1 and PDE5A2 gene have specific roles.

Past, Present and Future of PDE5 Inhibitor / 대한남성과학회지

The phosphodiesterase type-5 inhibitors (PDE5-Is) sildenafil, vardenafil and tadalafil are widely used as first-line therapy for erectile dysfunction (ED). Since the approval of sildenafil in 1998, more than 40 million men worldwide have been successfully treated with PDE5-Is. Pharmacologically, the proven safety and high tolerance of PDE5-Is is an attractive tool to investigate further physiological functions of PDE5, for example the modulation of intracellular cyclic GMP (cGMP) pools. As cGMP is a key component of intracellular signaling this may provide novel therapeutic opportunities beyond ED even for indications in which chronic administration is necessary. The approval of sildenafil for the treatment of pulmonary hypertension in 2005 was a notable success in this area of research. A number of other potential new indications are currently in various phases of preclinical research and development. In recent years, extensive but very heterogeneous information has been published in this field. The aim of this review is to summarize existing preclinical and clinical knowledge and critically discuss the evidence to support potential future indications for PDE5 inhibitors.