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Kidney Week

Abstract: PO1237

Tubular Flow Disruption During Cyst Development in Polycystic Kidney Disease

Session Information

Category: Genetic Diseases of the Kidneys

  • 1001 Genetic Diseases of the Kidneys: Cystic

Authors

  • Thomas, Isis, The University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Chweih, Hanan, The University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Haycraft, Courtney J., The University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Croyle, Mandy J., The University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Li, Zhang, The University of Alabama at Birmingham, Birmingham, Alabama, United States
  • Yoder, Bradley K., The University of Alabama at Birmingham, Birmingham, Alabama, United States
Background

Polycystic kidney disease is an inherited disorder in which clusters of cysts develop within the kidneys, causing the kidneys to enlarge and lose function. Cyst development can be due to functional changes caused by mutations in ciliary localized proteins Pkd1 and Pkd2 or changes in cilia formation/structure (e.g. ift88 mutants). It is currently unknown how cysts impact tubule flow and cilia, or whether flow alterations occur prior to or after cyst formation is initiated.

Methods

We used inducible Cre conditional mutant mouse models with an optical imaging chamber along with injection of fluorescent dextran to analyze tubule flow at multiple timepoints during cystogenesis in live kidneys. Additionally, we evaluated dextran absorption into proximal tubules as an indicator of tubule flow in mutant and control mice during cyst development. We determined the number of dextran+ proximal tubule cells by FACS to quantify changes in the percentage of tubules with flow in cystic versus non cystic kidneys. We performed H&E staining to quantify cyst severity and analyzed sections by immunofluorescent microscopy to assess changes in flow.

Results

Our results suggest that during the cyst formation, there is a marked decrease in flow through the tubules and that this reduction in flow occurs early during cyst formation. This corresponds to a 56.8% of cells that are both dextran+ and LTA+ (proximal tubule) by flow cytometry and similar results were obtained by IF analysis. We also find an increase in resident and infiltrating macrophages around the forming cysts.

Conclusion

The use of intravital imaging approaches allows us to evaluate changes in tubule flow as cysts progress. With the addition of cilia markers, we will examine the responses of the cilium to the changes in flow. Preliminary data suggests that that alterations in tubule flow occur at early time points during cyst initiation with larger cysts seldom containing epithelium that are dextran+. These data indicate that loss of tubule flow may be an early event associated with cystogenesis. Our data also suggests that disruption of tubule flow is progressive with fewer tubules with flow at later time points (4-6 months post induction). We are currently assessing whether there is an association between the disruption of flow in a tubule and localized immune responses.

Funding

  • NIDDK Support