Kidney Week

Abstract: FR-PO610

Labeling of Denatured Collagen in ADPKD and Comparison to Fibrotic Area

Session Information

• Cystic Kidney Diseases: Mechanisms and Models
  October 25, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidneys

• 1201 Genetic Diseases of the Kidneys: Cystic

Authors

• Sussman, Caroline R., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Caroline R. Sussman, PhD

• Holmes, Heather L., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Heather L. Holmes

• Addani, Mohamed Ahmed, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Mohamed Ahmed Addani

• Entriken, Seth M., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Seth M. Entriken

• Montgomery, Damon Anthony, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Damon Anthony Montgomery

• Obiorah, Angel Maame Afua, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Angel Maame Afua Obiorah

• Amin, Vibhuti, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Vibhuti Amin

• Webb, Kevin L., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Kevin L. Webb

• Anaam, Deema, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Deema Anaam, MBBS

• Alzamareh, Diana, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Diana Alzamareh

• Macura, Slobodan, Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Slobodan Macura, PhD

• Torres, Vicente E., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Vicente E. Torres, MD, PhD

• Kline, Timothy L., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Timothy L. Kline, MS, PhD

• Romero, Michael F., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Michael F. Romero, PhD

• Harris, Peter C., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States

Peter C. Harris, PhD

Background

Autosomal dominant polycystic kidney disease (ADPKD) is the fourth most common cause of kidney failure, and manifests through the proliferation of countless kidney cysts. Mounting research suggests the extracellular matrix (ECM) is integral to disease progression. Collagen, the predominant protein within the ECM, is encoded by 44 genes, forming intricate supramolecular structures that constitute 28 distinct collagen types. Methods used in ADPKD for tracking total collagen histologically are primarily trichrome or Picrosirius red (PSR) staining to determine percent fibrotic area. Besides fibrosis, destruction of collagen assemblies is a hallmark of tissue injury and disease. We examined here if denatured collagen is a more sensitive disease indicator than fibrotic area.

Methods

Pkd2^hi4166 zebrafish were used with heterozygous adults compared to sibling WT. Pkd1^RC/RC mice were used in C57BL/6J and compared to wildtype (Jackson Laboratory). Collagen hybridizing peptide (CHP, 3Helix) was used for fluorescence labeling of denatured collagen. CHP labeling was compared to fibrotic area determined from PSR staining. PSR staining, CHP labeling, and tissue area were calculated using ImageJ. Data are shown as mean ± SEM, p-values by t-test or ANOVA.

Results

CHP labeling surrounded 47.9% ± 14.5 of tubules in pkd2^+/- zebrafish (n=8 fish), while no labeling was seen in WT (n=10; p=0.002). Labeling occurred around both proximal tubules/collecting ducts (LTL+; 41.7% ± 25.0, n=4) and distal tubules (DBA+; 54.0% ± 18.2, n=4). Labeling in mouse was not clearly associated with individual tubules and was present in normal and cystic regions. Quantification of fluorescence-tagged CHP in entire kidney sections showed more labeling in Pkd1^RC/RC mice (581 au ± 68.3; n=6 mice) vs WT (341 au ± 14.4; n=6; p=0.006).

Conclusion

Denatured collagen labeling by CHP showed more consistent differences than fibrotic area by PSR. Additionally denatured collagen was detected distant from cysts in Pkd1^RC/RC mice and in pkd2^+/- zebrafish which lack cysts. These data suggest measuring denatured collagen may allow more reliable and sensitive detection of collagen changes in ADPKD than fibrotic area.

Funding

• NIDDK Support