SECUAH 2021 > Sevilleja-Ortiz etal 2021

dianas | Vol 10 No 1 | marzo 2021 | e202103b06

Diabetes is associated with functional alterations in rat and human penile vascular tissue through Orai channels

Alejandro Sevilleja-Ortiz, Argentina Fernández, Mariam El Assar, Esther García-Rojo, Borja García-Gómez, José María La Fuente, Javier Romero-Otero, Leocadio Rodríguez-Mañas, Javier Angulo

Hospital Universitario Ramón y Cajal. Ctra. de Colmenar Viejo km. 9,100 28034 Madrid

alex.sevilleja9335@gmail.com

VI Congreso de Señalización Celular, SECUAH 2021.
29 de marzo a 30 de abril, 2021. Universidad de Alcalá. Alcalá de Henares, Madrid. España.

Keywords: corpus cavernosum; human penile arteries; diabetes; erectile dysfunction; Orai channels; store-operated calcium entry

Abstract

Diabetic patients with erectile dysfunction (ED) are resistant to the conventional treatment of ED. Store-Operated Calcium Entry (SOCE) and its key players, stromal molecule (STIM) and Orai calcium channels, have been proposed as emergent therapeutic targets in cardiovascular pathophysiology and ED. The main objective of this project is to determine the influence of diabetes on the STIM/Orai system in cavernosal tissue from rats and patients with ED at functional and expression level. Rat corpus cavernosum (RCC) from rats with induced insulin-dependent diabetes, and human penile resistance arteries (HPRA) and corpus cavernosum (HCC) from 44 ED patients, who underwent penile prosthesis insertion, were divided into with (n=19) and without (n=25) type 2 diabetes and evaluated in wire myographs and/or organ chambers in presence of Orai channels inhibitors. Expression of STIM-1, Orai-1 and Orai-3 were determined by western blot and immunofluorescence in rat penis and human cavernosal tissues. Corpus cavernosum from diabetic rats displayed hypercontractility to norepinephrine (NE) (Emax 119.45±6.55% of K+ for NoDM, n=6, vs. 153.12±10.48% of K+ for DM, n=5, p<0.05). Treatment of cavernosal tissues with Orai channel inhibitor YM-58483 (20 μM) resulted in significant reduction of NE-induced contractions in both diabetic and non-diabetic rats, causing normalization of responses (87.49±3.48% for NoDM vs. 95.18±9.74% for DM, n.s.). Orai inhibition with YM-58483 was also able to reduce diabetes-related enhancement of contractions elicited by the thromboxane analogue, U46619, and neurogenic contractions induced by electrical field stimulation (EFS) in RCC from diabetic rats. In contrast, neurogenic (nitrergic) relaxations were potentiated by YM-58483 (10 µM) (Emax 45.37±5.95% vs. 71.72±5.83%, p < 0.05). YM-58483 did not modify relaxations induced by the NO donor, sodium nitroprusside (SNP) but significantly potentiated the relaxant capacity of the PDE5 inhibitor tadalafil (pEC50 4.40±0.03 vs. 5.43±0.29, p<0.01) in RCC from diabetic rats. HCC and HPRA displayed hypercontractility to NE as well. Treatment with YM-58483 (20 µM) inhibited NE-induced contractions from both diabetic and non-diabetic ED patients, being more marked in diabetic patients. Expression of the sensor protein STIM-1 was significantly down-regulated in RCC from diabetic rats. In contrast, expression of Orai-1 and Orai-3 was significantly increased in HCC from ED patients with diabetes. Contribution of Orai channels to vascular function of cavernosal tissue increases with diabetes. Protein expression of STIM/Orai is altered in cavernosal tissues from both diabetic rats and diabetic patients with ED. Orai inhibition could be a potential therapeutic strategy for being further evaluated in diabetic ED.