On 2016 Jan 09, Chao Liu commented:

Dr. Chen:

Your work is quiet interesting. I agree that dexamethasone can increase aquaporin-2 protein expression in in ex vivo inner medullary collecting duct suspensions. However, I have a different opinion about the effect of glucocorticoids dexamethasone on renal water and sodium excretion. Instead causing renal water and sodium retention, the emerging evidence show that glucocorticoids can promote renal water and sodium excretion (Glucocorticoids and renal Na+ transport: implications for hypertension and salt sensitivity. J Physiol. 2014 Apr 15;592(Pt8):1731-44.). “ Despite the widespread assumption that cortisol raises blood pressure as a consequence of renal sodium retention, there are few data consistent with the notion. Although it has a plethora of actions on brain, heart and blood vessels, kidney, and body fluid compartments, precisely how cortisol elevates blood pressure is unclear. Candidate mechanisms currently being examined include inhibition of the vasodilator nitric oxide system and increases in vasoconstrictor erythropoietin concentration.” (Cushing, cortisol, and cardiovascular disease. Hypertension. 2000 Nov;36(5):912-6. Review.) Moreover, there are a good body evidence, both from animal and human, shows that glucocorticoids could promote renal water and sodium excretion.

See the following citations:

1. Landínez RAS, Romero MFL, Maurice EH (2014). Efectos de la prednisona sobre la función renal a corto plazo en pacientes con Insuficiencia Cardíaca Descompensada. Venezolana de Medicina Interna 30(3): 176-192.

2. Liu C, Chen Y, Kang Y, Ni Z, Xiu H, Guan J, et al. (2011). Glucocorticoids Improve Renal Responsiveness to Atrial Natriuretic Peptide by Up-Regulating Natriuretic Peptide Receptor-A Expression in the Renal Inner Medullary Collecting Duct in Decompensated Heart Failure. J Pharmacol Exp Ther 339(1): 203-209.

3. Liu C, Liu G, Zhou C, Ji Z, Zhen Y, Liu K (2007). Potent diuretic effects of prednisone in heart failure patients with refractory diuretic resistance. Can J Cardiol 23(11): 865-868.

4. Liu C, Liu K (2014a). Effects of glucocorticoids in potentiating diuresis in heart failure patients with diuretic resistance. Journal of cardiac failure 20(9): 625-629.

5. Liu C, Liu K (2014b). Reply to Day et al.--hypouricemic effect of prednisone in heart failure: possible mechanisms. Can J Cardiol 30(3): 376 e373.

6. Liu C, Zhao Q, Zhen Y, Gao Y, Tian L, Wang L, et al. (2013). Prednisone in Uric Acid lowering in Symptomatic Heart Failure Patients With Hyperuricemia (PUSH-PATH) study. Can J Cardiol 29(9): 1048-1054.

7. Liu C, Zhao Q, Zhen Y, Zhai J, Liu G, Zheng M, et al. (2015). Effect of Corticosteroid on Renal Water and Sodium Excretion in Symptomatic Heart Failure: Prednisone for Renal Function Improvement Evaluation Study. J Cardiovasc Pharmacol 66(3): 316-322.

8. Meng H, Liu G, Zhai J, Zhen Y, Zhao Q, Zheng M, et al. (2015). Prednisone in Uric Acid Lowering in Symptomatic Heart Failure Patients with Hyperuricemia - The PUSH-PATH3 Study. The Journal of rheumatology 42(5): 866-869.

On 2016 Jan 09, Chao Liu commented:

Dr. Chen:

Your work is quiet interesting. I agree that dexamethasone can increase aquaporin-2 protein expression in in ex vivo inner medullary collecting duct suspensions. However, I have a different opinion about the effect of glucocorticoids dexamethasone on renal water and sodium excretion. Instead causing renal water and sodium retention, the emerging evidence show that glucocorticoids can promote renal water and sodium excretion (Glucocorticoids and renal Na+ transport: implications for hypertension and salt sensitivity. J Physiol. 2014 Apr 15;592(Pt8):1731-44.). “ Despite the widespread assumption that cortisol raises blood pressure as a consequence of renal sodium retention, there are few data consistent with the notion. Although it has a plethora of actions on brain, heart and blood vessels, kidney, and body fluid compartments, precisely how cortisol elevates blood pressure is unclear. Candidate mechanisms currently being examined include inhibition of the vasodilator nitric oxide system and increases in vasoconstrictor erythropoietin concentration.” (Cushing, cortisol, and cardiovascular disease. Hypertension. 2000 Nov;36(5):912-6. Review.) Moreover, there are a good body evidence, both from animal and human, shows that glucocorticoids could promote renal water and sodium excretion.

See the following citations:

1. Landínez RAS, Romero MFL, Maurice EH (2014). Efectos de la prednisona sobre la función renal a corto plazo en pacientes con Insuficiencia Cardíaca Descompensada. Venezolana de Medicina Interna 30(3): 176-192.

2. Liu C, Chen Y, Kang Y, Ni Z, Xiu H, Guan J, et al. (2011). Glucocorticoids Improve Renal Responsiveness to Atrial Natriuretic Peptide by Up-Regulating Natriuretic Peptide Receptor-A Expression in the Renal Inner Medullary Collecting Duct in Decompensated Heart Failure. J Pharmacol Exp Ther 339(1): 203-209.

3. Liu C, Liu G, Zhou C, Ji Z, Zhen Y, Liu K (2007). Potent diuretic effects of prednisone in heart failure patients with refractory diuretic resistance. Can J Cardiol 23(11): 865-868.

4. Liu C, Liu K (2014a). Effects of glucocorticoids in potentiating diuresis in heart failure patients with diuretic resistance. Journal of cardiac failure 20(9): 625-629.

5. Liu C, Liu K (2014b). Reply to Day et al.--hypouricemic effect of prednisone in heart failure: possible mechanisms. Can J Cardiol 30(3): 376 e373.

6. Liu C, Zhao Q, Zhen Y, Gao Y, Tian L, Wang L, et al. (2013). Prednisone in Uric Acid lowering in Symptomatic Heart Failure Patients With Hyperuricemia (PUSH-PATH) study. Can J Cardiol 29(9): 1048-1054.

7. Liu C, Zhao Q, Zhen Y, Zhai J, Liu G, Zheng M, et al. (2015). Effect of Corticosteroid on Renal Water and Sodium Excretion in Symptomatic Heart Failure: Prednisone for Renal Function Improvement Evaluation Study. J Cardiovasc Pharmacol 66(3): 316-322.

8. Meng H, Liu G, Zhai J, Zhen Y, Zhao Q, Zheng M, et al. (2015). Prednisone in Uric Acid Lowering in Symptomatic Heart Failure Patients with Hyperuricemia - The PUSH-PATH3 Study. The Journal of rheumatology 42(5): 866-869.