Kidney Week

Abstract: SA-OR043

Development of a Standardized Method for Ex Vivo Respirometry in Intact Kidney Tissue to Assess Regional Metabolism

Session Information

• Exploring Dietary, Exercise, and Microbiome Interventions in CKD
  November 08, 2025 | Location: Room 360A, Convention Center
  Abstract Time: 05:30 PM - 05:40 PM

Category: Health Maintenance, Nutrition, and Metabolism

• 1500 Health Maintenance, Nutrition, and Metabolism

Authors

• Bessho, Ryoichi, Vanderbilt University Medical Center, Nashville, Tennessee, United States

Ryoichi Bessho, MD, PhD

• Haase, Volker H., Vanderbilt University Medical Center, Nashville, Tennessee, United States

Volker H. Haase, MD, DrMed

Background

A comprehensive spatial analysis of kidney metabolism is essential for advancing knowledge of normal kidney physiology and pathophysiology. The kidney exhibits distinct regional variations in mitochondrial metabolism, substrate utilization and bioenergetic profiles, reflecting the unique functional profiles of each nephron segment. Traditional methods rely on disrupted tissue or cultured cells, which fail to capture the dynamic differences in metabolic flux across kidney regions. To overcome this limitation, we have developed a standardized method for assessing the bioenergetic profiles of intact cortical and medullary kidney tissue.

Methods

We used 8-week-old C57BL/6J mice to generate 1 mm punch biopsies from vibratome-cut 100 μm kidney slices. Kidney tissue discs were loaded into 24-well Islet Capture Microplates and analyzed on a Seahorse XFe24 platform. As substrates in this assay, we prioritized palmitate and glucose, two major exogenous metabolic fuels utilized by the kidney under physiological conditions.

Results

Cortical tissue exhibited the highest level of ATP-linked respiration (Cortex: 873.94 ± 89.63 vs outer medulla: 345.47 ± 35.32 and inner medulla: 529.61 ± 50.93 pmol/min/mm³), consistent with its reliance on oxidative phosphorylation. In contrast, the extracellular acidification rate (ECAR) was most pronounced in the outer medulla (367.51 ± 70.21 mpH/min/mm³), where it was two-fold higher than in cortex and inner medulla. To demonstrate the utility of our approach for drug development, we examined the effects of pharmacological hypoxia-inducible factor (HIF) activation on regional kidney bioenergetics. HIF activation with pan-prolyl-hydroxylase (PH) inhibitor IOX2 increased ECAR in the cortex (246.12 ± 39.00 vs. 180.34 ± 23.41 mpH/min/mm³ for vehicle) but not in the outer medulla, consistent with HIF’s role in regulating anaerobic glycolysis and indicating differential effects of HIF-PH inhibition on regional kidney metabolism.

Conclusion

In summary, we developed a robust and standardized protocol for measuring respiration in architecture-preserved kidney slices. This protocol advances the study of kidney metabolism by enabling region-specific insights into kidney respiration and bioenergetics, with potential applications in the development of novel therapeutics targeting kidney metabolic pathways.

Funding

• NIDDK Support

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025zzz9smee