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Abstract: TH-PO747

Evaluation of Renal Fibrosis Using Elastic Scattering Spectrophotometry (ESS)

Session Information

  • Bioengineering
    October 25, 2018 | Location: Exhibit Hall, San Diego Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Bioengineering

  • 300 Bioengineering

Authors

  • Belghasem, Mostafa, Boston University School of Medicine, Boston, Massachusetts, United States
  • A'Amar, Ousama, Boston University, Dorchester, Massachusetts, United States
  • Roth, Daniel M., Boston University School of Medicine, Boston, Massachusetts, United States
  • Arinze, Nkiruka, Boston University School of Medicine, Boston, Massachusetts, United States
  • Richards, Sean, Boston University Medical Center, Boston, Massachusetts, United States
  • Walker, Joshua A., Boston University School of Medicine, Boston, Massachusetts, United States
  • Francis, Jean M., Boston University Medical Center, Boston, Massachusetts, United States
  • Salant, David J., Boston University Medical Center, Boston, Massachusetts, United States
  • Chitalia, Vipul C., Boston University Medical Center, Boston, Massachusetts, United States
  • Bigio, Irving J., Boston University, Dorchester, Massachusetts, United States
Background

Interstitial fibrosis and tubular atrophy (IFTA) are hallmarks of progressive CKD. The standard method of assessment requires one or more biopsy cores and semiquantitative measurement by histology using stains such as Masson’s trichrome. The method is invasive, labor intensive and fraught with potential sampling error due to the patchy nature of IFTA. We propose an alternative, quantitative, minimally invasive method of fine-needle sampling at several sites using Elastic-Scattering Spectroscopy (ESS). ESS is a broadly applicable method that measures wavelength-dependence of optical scattering probability of tissue and is sensitive to the amount of fibrosis.

Methods

ESS was performed using three animal models (n=5 per model) of renal fibrosis (adenine-induced CKD, unilateral ureteral obstruction (UUO) and a remnant kidney model). The ESS spectrum was obtained using a fiberoptic probe with a 150 µm illumination fiber and a 100µm collection fiber, with measurements recorded from several points in the cortex and the medulla of the kidneys. The spectra were normalized at 650 nm to facilitate comparison of the spectral shapes to the ESS spectra obtained from time = 0 (untreated controls). The ESS spectra were correlated with the amount of fibrosis measured by trichrome staining.

Results

All three models were associated with a rise of BUN and an increase in IFTA. Adenine-induced fibrotic kidneys showed a distinct spectral trend of increased scattering intensity in the ultraviolet region (300-400 nm) compared to normal kidneys. Similar spectral changes were observed in the UUO model, with the degree of spectral change dependent on the time after ligation. A linear correlation was observed between fibrosis as assessed by Trichrome stain and the ESS spectral feature.

Conclusion

The linear correlation for even this small data set is encouraging and bodes well for ESS as a quantitative measure of IFTA. Collectively, these data support further studies to explore ESS as a viable point-of-care technique to detect renal fibrosis quickly, offering the potential for a rapid, quantitative and objective assessment of fibrotic status, overcoming some of the limitations of the current method.