Abstract: FR-PO994

Multiscale Mechanical Properties of Glycated Kidney Extracellular Matrix

Session Information

Category: Bioengineering and Informatics

  • 101 Bioengineering and Informatics

Authors

  • Ferrell, Nicholas J., Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Dillender, Sarah, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Agarwal, Rishabh, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Abidi, Minhal Haider, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Walker, Gwyneth D, Vanderbilt University Medical Center, Nashville, Tennessee, United States
Background

Non-enzymatic glycation of the extracellular matrix (ECM) contributes to diabetic nephropathy. A subset of advanced glycation end-products (AGEs) crosslink the ECM and may increase ECM stiffness. Matrix stiffening is recognized as a contributor to progression of fibrotic diseases, but the role of non-enzymatic stiffening of kidney ECM in the progression of diabetic nephropathy is not well understood and may provide new targets for intervention. The aim of this work was to evaluate the degree to which ex vivo glycation increased the stiffness of cortical, glomerular, and tubular ECM using multiple biomechanical characterization techniques.

Methods

Cortical and glomerular ECM were isolated from porcine kidney cortex by gross dissection and differential sieving, respectively. Mouse tubules were isolated from wild type mouse kidneys by microdissection. ECM was decellularized and evaluated by histology and immunostaining to evaluate the effects of decellularization on ECM structure. ECM was glycated by incubation in glucose or ribose (0-500 mM) for 30 days. Following glycation, ECM was subjected to either compressive or tensile mechanical testing using custom microscale measurement techniques (for tubules and glomeruli) or commercial testing techniques (for cortical matrix).

Results

Histological examination and immunostaining for ECM proteins (collagen IV and laminin) showed that structural proteins were retained in the ECM and the matrix largely retained its three dimensional structure following decellularization. Biomechanical testing showed that glycation increased ECM elastic modulus (stiffness) following exposure to both glucose and ribose at concentrations >5 mM. This effect was more pronounced for ribose given its higher reactivity relative to glucose. The origin of the ECM (cortical, glomerular, or tubular) and the method of applied stress (tension or compression) had a significant effect on the measured stiffness. This variability is likely due structural differences between the matrix components and anisotropy in the tensile versus compressive mechanical properties.

Conclusion

These data suggest a potential role for ECM stiffening in progression of diabetic kidney disease. Care should be taken in interpretation of the measured elastic modulus depending on the origin of the matrix and the method of characterizing the ECM stiffness.

Funding

  • NIDDK Support