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Abstract: SA-PO978

Role of Apoptotic Cells in Mediating Progressive CKD

Session Information

  • CKD: Pathobiology - II
    November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

  • 2203 CKD (Non-Dialysis): Mechanisms

Authors

  • Cechova, Sylvia, University of Virginia, Charlottesville, Virginia, United States
  • Poudel, Nabin, University of Virginia, Charlottesville, Virginia, United States
  • Okusa, Mark D., University of Virginia, Charlottesville, Virginia, United States
  • Lobo, Peter I., University of Virginia, Charlottesville, Virginia, United States

Group or Team Name

  • Division of Nephrology and Center for Immunity, Inflammation and Regenerative Medicine
Background


Chronic kidney disease (CKD) is primarily caused by diabetes, hypertension, and acute kidney injury (AKI), but the pathophysiological mechanism leading to the progression of CKD is still not completely understood. Primarily, CKD progression is attributed to intra-glomerular hypertension and renal tubular damage induced by hyperglycemia leading to proteinuria. Recently, several investigators have suggested that failed repair of renal tubules, damaged during AKI, contribute to pathogenesis of CKD progression. In this present study, we investigated the role of continued apoptotic cell death, post-AKI, in mediating CKD progression.

Methods

We performed unilateral ischemia reperfusion injury (u-IRI; 30 min) on C57BL/6 mice to induce CKD. Group 1 mice were subjected to nephrectomy on the non-ischemic contralateral kidney on day 4, and were euthanized on day 7. Group 2 mice underwent nephrectomy on day 27 and were euthanized on day 28. We collected plasma and kidney tissues. The relative mRNA expression of fibrotic, and pro-apoptotic genes were estimated by real-time PCR. To evaluate extent of kidney injury, we measured plasma creatinine and stained kidney section with Masson’s Trichrome to quantitate the degree of fibrosis. Additionally, we performed Western blotting to quantify the level of cleaved Caspase 3 in the kidney tissue lysates and stained kidney section with cleaved Caspase 3 antibody.

Results

We observed significant upregulation of fibrotic and pro-apoptotic genes in Group 1 mice compared to Group 2 mice. IRI injured kidney progressed to CKD: day 7 plasma creatinine 0.72±0.13mg/dl for Group1 and day 28 plasma creatinine: 2.44±0.29 mg/dl; P=0.0006; n=5 for Group2. Masson’s Trichrome staining revealed that Group 1 mice sustained significantly less injury when compared to Group 2. Additionally, there was no decrease in apoptosis with CKD progression: with Western blotting (Relative c-cleaved Caspase 3 protein level: Group 1: 1.01±0.13; Group 2: 1.43±0.18, P=NS; n=3), and with HRP-cleaved Caspase 3 staining, on day 28, there was more apoptosis and more CKD injury than on day 7 after IRI.

Conclusion

Our data suggest that apoptotic cells play a role in both phases i.e. during the acute phase of IRI and in the progressive CKD phase. However, further studies are necessary to elucidate the contribution of apoptotic signaling pathway to progression of CKD.

Funding

  • NIDDK Support