RESUMEN
Arginase 1 and Arginase 2 are homologous enzymes that convert l-Arginine to Urea and l-ornithine and compete with nitric oxide synthases for l-Arginine. Increased Arginase 1 and 2 activity may reduce nitric oxide production by the endothelium in disease states, including erectile dysfunction (ED). Here we aimed at assessing whether Arginase 1 and 2 plasma levels, plasma arginase activity, or genetic factors are associated with ED risk and severity. Blood samples were collected from healthy controls (n = 106) and from patients with ED (n = 110) after completion of the IIEF questionnaire (international index of erectile function). Plasma Arginase 1 and 2 concentrations were assessed by ELISA, while plasma arginase activity was measured by spectrophotometry. Genotypes of ARG1 (rs2781659, rs2781667, rs2246012 and rs17599586) and ARG2 (rs3742879 and rs10483801) were determined by Taqman genotyping assays by real-time polymerase chain reaction. Increased Arginase 2 concentrations were found in clinical ED and are associated with increased risk for ED. ARG1 rs2781659 AA and rs2781667 TT genotypes are associated with lower IIEF scores (higher severity) only in clinical ED. Similarly, the ARG1 GTCC haplotype is associated with higher IIEF scores in clinical ED. This study shows that plasma Arginase 2 concentrations may serve as risk factor for ED. Besides, Arginase 1 genetic variations affect ED severity.
Asunto(s)
Arginasa/sangre , Arginasa/genética , Disfunción Eréctil/enzimología , Disfunción Eréctil/genética , Polimorfismo Genético , Adulto , Anciano , Anciano de 80 o más Años , Disfunción Eréctil/sangre , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Índice de Severidad de la Enfermedad , Encuestas y CuestionariosRESUMEN
AIM: Sildenafil potentiates the nitric oxide (NO) signaling pathway. Since neuronal NOS is very important in the penis, we assessed whether NOS1 polymorphisms are associated with altered responsiveness to sildenafil in erectile dysfunction (ED). MATERIALS & METHODS: Patients (n = 137) were divided as clinical ED or postoperative ED. They were subdivided as good responders or poor responders to sildenafil, and genotypes for rs41279104 and rs2682826 NOS1 polymorphisms were determined. RESULTS: We found that the rs41279104 CT genotype was associated with good responders in postoperative ED patients, while rs2682826 CT genotype was associated with good responders in postoperative ED, and the TT genotype associated with good responders in both groups. Finally, the CT haplotype was associated with good responders in postoperative ED. CONCLUSION: NOS1 polymorphisms are associated with responsiveness to sildenafil in ED. Original submitted 20 November 2013; Revision submitted 31 January 2014.
Asunto(s)
Disfunción Eréctil/tratamiento farmacológico , Disfunción Eréctil/genética , Óxido Nítrico Sintasa de Tipo I/genética , Piperazinas/uso terapéutico , Polimorfismo Genético/genética , Sulfonas/uso terapéutico , Haplotipos , Humanos , Masculino , Persona de Mediana Edad , Periodo Posoperatorio , Purinas/uso terapéutico , Citrato de SildenafilRESUMEN
Erectile dysfunction (ED) is a multifactorial disease associated with vascular dysfunction, low nitric oxide (NO) bioavailability, and oxidative stress. However, it is not known whether low NO bioavailability and oxidative stress affect the responsiveness of ED patients to sildenafil. We tested this hypothesis by studying 28 healthy subjects (control group), 26 patients with ED without comorbidities (ED group), and 18 patients with ED and diabetes mellitus (ED/DM group). The International Index for Erectile Function (IIEF) questionnaire was used to assess the erectile function of all participants, and their responsiveness to sildenafil was assessed as the percentage of change in the five-item version of IIEF score before and after sildenafil treatment. Levels of whole blood nitrite, antioxidants markers (ferric reducing ability of plasma (FRAP) and reduced glutathione), and oxidative stress markers (thiobarbituric acid reactive substance and protein carbonyl) were determined. We found a negative correlation between whole blood nitrite levels and the responses to sildenafil in both ED groups (P<0.05). FRAP correlated negatively with the responses to sildenafil in the ED/DM group (P<0.05). No other significant associations were found. Our findings show evidence that low NO bioavailability is associated with better responses to sildenafil in patients with ED (with or without DM).