Kidney Week

Abstract: SA-PO1198

Association of Urinary Mitochondrial DNA with Skin Capillary Density in CKD: MAP-CKD Study

Session Information

• CKD: Biomarkers and Emerging Tools for Diagnosis and Monitoring
  November 08, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2302 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

• Ahmadi, Armin, University of California San Diego, La Jolla, California, United States

Armin Ahmadi, PhD

• Li, Xinrui, University of California San Diego, La Jolla, California, United States

Xinrui Li

• Rahaman, Masfiqur, University of California San Diego, La Jolla, California, United States

Masfiqur Rahaman, MSc

• Harsh, Amol, Plaksha University, Sahibzada Ajit Singh Nagar, PB, India

Amol Harsh

• Ghanim, Basma, University of California San Diego, La Jolla, California, United States

Basma Ghanim

• Hepokoski, Mark, University of California San Diego, La Jolla, California, United States

Mark Hepokoski, MD

• Houben, Alfons Jhm, Maastricht Universitair Medisch Centrum+, Maastricht, LI, Netherlands

Alfons Jhm Houben, PhD

• Rahman, Tauhidur, University of California San Diego, La Jolla, California, United States

Tauhidur Rahman, PhD

• Ix, Joachim H., University of California San Diego, La Jolla, California, United States

Joachim H. Ix, MD, FASN

• Malhotra, Rakesh, University of California San Diego, La Jolla, California, United States

Rakesh Malhotra, MD, MPH, FASN

Background

Elevated urinary mitochondrial DNA (mtDNA) may reflect kidney injury. Microvascular disease is central to development of CKD. The relationship of urine mtDNA with peripheral microvascular health in CKD remains unknown.

Methods

We recruited 98 adults with CKD with eGFR <60 mL/min/1.73 m² Absolute urinary mtDNA levels were quantified using droplet digital PCR targeting the NADH dehydrogenase 1 (ND1) gene. Finger skin capillary density was assessed using a digital video microscope (Capiscope; KK Technology, United Kingdom) at 100x magnification. The number of erythrocyte-perfused capillaries per 1 mm² skin was quantified over 15 seconds. Spearman correlation coefficient was used to assess relationship between urinary mtDNA and skin capillary density.

Results

Among 59 participants with eGFR <60 mL/min/1.73 m², the mean (SD) age was 66 (14) years with a mean eGFR of 36 (14) (mL/min/1.73 m²) and 49% were female, 47% had diabetes, and 88% had hypertension. The mean capillary count was 53 (11) per mm². The median urinary mtDNA level was 8.3 ND1 copies/ul (IQR of 3.7-26.6). Higher urinary mtDNA was significantly correlated with lower capillary density (r=-0.35, P<0.01) (Figure 1).

Conclusion

In CKD patients, higher urinary mtDNA levels are correlated with reduced skin nail-fold capillary density. Urinary mtDNA may reflect systemic microvascular dysfunction and could serve as a non-invasive biomarker of vascular injury in CKD.

Figure 1. The association between urinary mtDNA and skin capillary density in CKD (n=59).

Funding

• NIDDK Support

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.20257a9hysnd