Kidney Week

Abstract: SA-PO089

Tertiary Lymphoid Structures and Late-Stage Lymphangiogenesis at Very-Late Time Points following Ischemic Kidney Injury

Session Information

• AKI: Inflammation and Cell Cycle
  October 26, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 103 AKI: Mechanisms

Authors

• Ghajar-Rahimi, Gelare, The University of Alabama at Birmingham, Birmingham, Alabama, United States

Gelare Ghajar-Rahimi, PhD

• Melkonian, Arin, The University of Alabama at Birmingham, Birmingham, Alabama, United States

Arin Melkonian, MS

• Barwinska, Daria, Indiana University School of Medicine, Indianapolis, Indiana, United States

Daria Barwinska, PhD

• Whipple, Grace, The University of Alabama at Birmingham, Birmingham, Alabama, United States

Grace Whipple

• Kamocka, Malgorzata, Indiana University School of Medicine, Indianapolis, Indiana, United States

Malgorzata Kamocka, PhD

• Winfree, Seth, University of Nebraska Medical Center, Omaha, Nebraska, United States

Seth Winfree, MS, PhD

• George, James F., The University of Alabama at Birmingham, Birmingham, Alabama, United States

James F. George, PhD

• Lee, Timmy C., The University of Alabama at Birmingham, Birmingham, Alabama, United States

Timmy C. Lee, MD, MPH, FASN

• El-Achkar, Tarek M., Indiana University School of Medicine, Indianapolis, Indiana, United States

Tarek M. El-Achkar, MD, FASN

• Agarwal, Anupam, The University of Alabama at Birmingham, Birmingham, Alabama, United States

Anupam Agarwal, MD, FASN

Background

The role of the lymphatic system in the transition from AKI to CKD is unknown. In several AKI models, kidney lymphatics undergo expansion or lymphangiogenesis (LA), which is considered acutely protective, but long-term changes post-injury have not been assessed. This study aimed to determine if long-term alterations in kidney lymphatics persist and their relationship to inflammation and injury.

Methods

C57BL/6J mice underwent bilateral ischemia-reperfusion injury (BIRI) and were followed for 9 months. Kidney function was assessed using serial glomerular filtration rate (GFR) measurements. The abundance and spatial distribution of LYVE-1+ lymphatic vessels were determined using quantitative three-dimensional tissue cytometry (3DTC). Lymphangiogenesis (LA) was evaluated by quantitative real-time PCR for lymphangiogenic markers. Single-cell and single-nucleus transcriptomic datasets of murine and human endothelial cells were analyzed to identify additional target genes. Sequential immunofluorescence characterized tertiary lymphoid structures in the kidney.

Results

BIRI induced AKI within 24 hours. While GFR recovered, BIRI mice showed progressive histological signs of CKD overtime, including fibrosis and CCR7+ lymphoid aggregates. Sham-operated mice did not display these phenotypes. 3DTC revealed an increase in cortical LYVE-1+ vessels in BIRI compared to sham groups at 3 days and 6 months post-surgery, with no significant difference at intermediate time points. Expression of lymphatic marker gene Flt4 and Lyve1 increased acutely, while Flt4, Lyve1, and Pdpn were elevated later. Increased Ccl21a expression was detected in kidneys collected 6 months after BIRI. Single-cell/nucleus transcriptomics suggest the source of Ccl21a is likely a subpopulation of lymphatic endothelial cells.

Conclusion

Three distinct phases of kidney lymphatic responses occur after BIRI: acute LA, an intermediate regression to a basal phenotype, and late-stage LA coinciding with increased Ccl21a expression and tertiary lymphoid tissue formation. Future studies will aim to examine the precise spatial and functional relationship between injury-associated lymphatics, tertiary lymphoid structures and kidney function.

Funding

• Veterans Affairs Support