Sonia Prince

Benefit of Mineralocorticoid Receptor Antagonism in AKI: Role of Vascular Smooth Muscle Rac1

AKI is a frequent complication in hospitalized patients. Unfortunately, there is no effective pharmacologic approach for treating or preventing AKI. In rodents, mineralocorticoid receptor (MR) antagonism prevents AKI induced by ischemia-reperfusion (IR). We investigated the specific role of vascular MR in mediating AKI induced by IR. We also assessed the protective effect of MR antagonism in IR-induced AKI in the Large White pig, a model of human AKI. In mice, MR deficiency in smooth muscle cells (SMCs) protected against kidney IR injury. MR blockade by the novel nonsteroidal MR antagonist, finerenone, or genetic deletion of MR in SMCs associated with weaker oxidative stress production. Moreover, ischemic kidneys had higher levels of Rac1-GTP, required for NADPH oxidase activation, than sham control kidneys, and genetic deletion of Rac1 in SMCs protected against AKI. Furthermore, genetic deletion of MR in SMCs blunted the production of Rac1-GTP after IR. Pharmacologic inhibition of MR also prevented AKI induced by IR in the Large White pig. Altogether, we show that MR antagonism, or deletion of the MR gene in SMCs, limited the renal injury induced by IR through effects on Rac1-mediated MR signaling. The benefits of MR antagonism in the pig provide a rational basis for future clinical trials assessing the benefits of this approach in patients with IR-mediated AKI.

Nonsteroidal Mineralocorticoid Receptor Antagonist Finerenone Protects Against Acute Kidney Injury–Mediated Chronic Kidney DiseaseNovelty and Significance: Role of Oxidative Stress

Acute kidney injury induced by ischemia/reperfusion (IR) is a frequent complication in hospitalized patients. Mineralocorticoid receptor antagonism has shown to be helpful against renal IR consequences; however, the potential benefit of novel nonsteroidal mineralocorticoid receptor antagonists such as finerenone has to be further explored. In this study, we evaluated the efficacy of finerenone to prevent the acute and chronic consequences of ischemic acute kidney injury. For the acute study (24 hours), 18 rats were divided into sham, bilateral renal ischemia of 25 minutes, and rats that received 3 doses of finerenone at 48, 24, and 1 hour before the ischemia. For the chronic study (4 months), 23 rats were divided into sham, rats that underwent 45 minutes of bilateral ischemia, and rats treated with finerenone at days 2 and 1 and 1 hour before IR. We found that after 24 hours of reperfusion, the untreated IR rats presented kidney dysfunction and tubular injury. Kidney injury molecule-1 and neutrophil gelatinase associated to lipolacin mRNA levels were increased. In contrast, the rats treated with finerenone displayed normal kidney function and significantly lesser tubular injury and kidney injury molecule-1 and neutrophil gelatinase associated to lipolacin levels. After 4 months, the IR rats developed chronic kidney disease, evidenced by kidney dysfunction, increased proteinuria and renal vascular resistance, tubular dilation, extensive tubule-interstitial fibrosis, and an increase in kidney transforming growth factor-&bgr; and collagen-I mRNA. The transition from acute kidney injury to chronic kidney disease was fully prevented by finerenone. Altogether, our data show that in the rat, finerenone is able to prevent acute kidney injury induced by IR and the chronic and progressive deterioration of kidney function and structure.

Nonsteroidal Mineralocorticoid Receptor Antagonist Finerenone Protects Against Acute Kidney Injury–Mediated Chronic Kidney Disease

Acute kidney injury induced by ischemia/reperfusion (IR) is a frequent complication in hospitalized patients. Mineralocorticoid receptor antagonism has shown to be helpful against renal IR consequences; however, the potential benefit of novel nonsteroidal mineralocorticoid receptor antagonists such as finerenone has to be further explored. In this study, we evaluated the efficacy of finerenone to prevent the acute and chronic consequences of ischemic acute kidney injury. For the acute study (24 hours), 18 rats were divided into sham, bilateral renal ischemia of 25 minutes, and rats that received 3 doses of finerenone at 48, 24, and 1 hour before the ischemia. For the chronic study (4 months), 23 rats were divided into sham, rats that underwent 45 minutes of bilateral ischemia, and rats treated with finerenone at days 2 and 1 and 1 hour before IR. We found that after 24 hours of reperfusion, the untreated IR rats presented kidney dysfunction and tubular injury. Kidney injury molecule-1 and neutrophil gelatinase associated to lipolacin mRNA levels were increased. In contrast, the rats treated with finerenone displayed normal kidney function and significantly lesser tubular injury and kidney injury molecule-1 and neutrophil gelatinase associated to lipolacin levels. After 4 months, the IR rats developed chronic kidney disease, evidenced by kidney dysfunction, increased proteinuria and renal vascular resistance, tubular dilation, extensive tubule-interstitial fibrosis, and an increase in kidney transforming growth factor-&bgr; and collagen-I mRNA. The transition from acute kidney injury to chronic kidney disease was fully prevented by finerenone. Altogether, our data show that in the rat, finerenone is able to prevent acute kidney injury induced by IR and the chronic and progressive deterioration of kidney function and structure.

Nonsteroidal Mineralocorticoid Receptor Antagonist Finerenone Protects Against Acute Kidney Injury–Mediated Chronic Kidney DiseaseNovelty and Significance

Acute kidney injury induced by ischemia/reperfusion (IR) is a frequent complication in hospitalized patients. Mineralocorticoid receptor antagonism has shown to be helpful against renal IR consequences; however, the potential benefit of novel nonsteroidal mineralocorticoid receptor antagonists such as finerenone has to be further explored. In this study, we evaluated the efficacy of finerenone to prevent the acute and chronic consequences of ischemic acute kidney injury. For the acute study (24 hours), 18 rats were divided into sham, bilateral renal ischemia of 25 minutes, and rats that received 3 doses of finerenone at 48, 24, and 1 hour before the ischemia. For the chronic study (4 months), 23 rats were divided into sham, rats that underwent 45 minutes of bilateral ischemia, and rats treated with finerenone at days 2 and 1 and 1 hour before IR. We found that after 24 hours of reperfusion, the untreated IR rats presented kidney dysfunction and tubular injury. Kidney injury molecule-1 and neutrophil gelatinase associated to lipolacin mRNA levels were increased. In contrast, the rats treated with finerenone displayed normal kidney function and significantly lesser tubular injury and kidney injury molecule-1 and neutrophil gelatinase associated to lipolacin levels. After 4 months, the IR rats developed chronic kidney disease, evidenced by kidney dysfunction, increased proteinuria and renal vascular resistance, tubular dilation, extensive tubule-interstitial fibrosis, and an increase in kidney transforming growth factor-&bgr; and collagen-I mRNA. The transition from acute kidney injury to chronic kidney disease was fully prevented by finerenone. Altogether, our data show that in the rat, finerenone is able to prevent acute kidney injury induced by IR and the chronic and progressive deterioration of kidney function and structure.

0278 : Mineralocorticoid receptor antagonism with BR-4628 protects against renal injury induced by ischemia/reperfusion

Introduction The main cause of acute kidney injury (AKI) is ischemia/ reperfusion (IR). AKI has been associated with chronic kidney disease progression and cardiac alterations. Previous studies showed that in a rat model of kidney IR, mineralocorticoid receptor (MR) antagonism with spironolactone prevents tubular injury and renal dysfunction. Despite their benefits in renal diseases, the current MR antagonists have strong limitations like hyperkalemia, thus motivating the search of novel antagonists with safer profile. Objective Test the efficacy of the non-steroidal MR antagonist BR-4628 against renal injury induced by IR. Methods Twenty male wistar rats were divided in 4 groups: sham-operated (S), bilateral renal ischemia (IR) for 25min, treated with BR-4628 (10mg/kg) either 3 days before IR (B10-pre) or 3 hours after IR (B10-post). All groups were studied 24h after reperfusion. Blood sample was taken for creatinine and urea quantification. The right kidney was processed for molecular studies and the left for histopathological analysis. Results Rats with IR developed renal injury characterized by renal dysfunction, increase in tubular injury markers (Hsp72 and Kim-1), oxidized proteins and pro-inflammatory cytokines. These alterations were absent in the B10-pre and B10-post IR groups. IR induced an increased expression of the M1 macrophage markers iNOS, CCL3, TNF-alpha and MCP-1 (inflammatory phenotype) that was fully prevented with the BR-4628 pre-treatment. Furthermore we observed that in the B10-pre and B10-post groups there was a greater expression of M2 macrophage markers; IL4r, FIZZ1 and Igfr2 (wound healing phenotype), as compared to the non-treated IR group. Conclusion We show for the first time that the non-steroidal BR-4628 MR antagonist is effective to prevent or treat renal injury induced by IR possibly through a mechanism involving macrophage polarization towards the wound healing phenotype.

0307 Role of vascular mineralocorticoid receptor in renal injury induced by ischemia/reperfusion

Introduction Acute kidney injury (AKI) is defined as an abrupt decrease (48h) in kidney function. One of the main causes of AKI is ischemia/reperfusion (I/R). AKI is related with high mortality, chronic kidney disease development and cardiac alterations like heart failure and arrhythmias. Mineralocorticoid receptor (MR) antagonism with spironolactone (Sp) prevents tubular injury and renal dysfunction induced by I/R in the rat. Although there is information supporting a role for aldosterone and MR in kidney injury, it remains unexplored the specific role of the MR expressed in the vasculature in mediating the deleterious effects of aldosterone during renal I/R. Objective To study the effect of inducing I/R in mice lacking the MR specifically in the endothelial cells or in the vascular smooth muscle cells. Methods To test if Sp is also able to prevent renal injury induced by I/R in the mice with the C57BL/6 background (same as MR KO mice) we included three groups of mice: 1) Sham, 2) I/R 20 min and 3) I/R 20 min + Sp pre-treatment. We analyzed the presence of renal dysfunction and inflammatory cytokines. In the MR KO mice, we will analyze the effect of MR deficiency after renal I/R in an acute phase (24h) and in chronic kidney disease development (after 4 weeks). In the acute studies the mechanisms that will be explored include: polarization of macrophages, endothelial injury and oxidative stress. In the chronic studies we will test if the wild type or MR knockout mice develop CKD as a consequence of renal I/R. Results Mice underwent renal I/R developed injury characterized by increased serum creatinine and urea levels, urinary Hsp72 and elevation in the mRNA of TNF-alpha and MCP-1 pro-inflammatory cytokines. These alterations were prevented by the Sp pre-treatment. Conclusion The protective effect of Sp against renal I/R that was previously reported in the rat is also observed in the C57BL/6 mice and supports the study of the MR KO mice in the renal I/R setting.