Metabolic imaging of fatty kidney in diabesity: validation and dietary intervention

Nephrol Dial Transplant. 2018 Feb 1;33(2):224-230. doi: 10.1093/ndt/gfx243.

Abstract

Background: Obesity and type 2 diabetes have not only been linked to fatty liver, but also to fatty kidney and chronic kidney disease. Since non-invasive tools are lacking to study fatty kidney in clinical studies, we explored agreement between proton magnetic resonance spectroscopy (1H-MRS) and enzymatic assessment of renal triglyceride content (without and with dietary intervention). We further studied the correlation between fatty kidney and fatty liver.

Methods: Triglyceride content in the renal cortex was measured by 1H-MRS on a 7-Tesla scanner in 27 pigs, among which 15 minipigs had been randomized to a 7-month control diet, cafeteria diet (CAF) or CAF with low-dose streptozocin (CAF-S) to induce insulin-independent diabetes. Renal biopsies were taken from corresponding MRS-voxel locations. Additionally, liver biopsies were taken and triglyceride content in all biopsies was measured by enzymatic assay.

Results: Renal triglyceride content measured by 1H-MRS and enzymatic assay correlated positively (r = 0.86, P < 0.0001). Compared with control diet-fed minipigs, renal triglyceride content was higher in CAF-S-fed minipigs (137 ± 51 nmol/mg protein, mean ± standard error of the mean, P < 0.05), but not in CAF-fed minipigs (60 ± 10 nmol/mg protein) compared with controls (40 ± 6 nmol/mg protein). Triglyceride contents in liver and kidney biopsies were strongly correlated (r = 0.97, P < 0.001).

Conclusions: Non-invasive measurement of renal triglyceride content by 1H-MRS closely predicts triglyceride content as measured enzymatically in biopsies, and fatty kidney appears to develop parallel to fatty liver. 1H-MRS may be a valuable tool to explore the role of fatty kidney in obesity and type 2 diabetic nephropathy in humans in vivo.

Keywords: chronic kidney disease; fatty kidney; proton magnetic; renal triglyceride content; resonance spectroscopy; type 2 diabetes mellitus.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Animals
  • Diabetes Mellitus, Experimental* / diet therapy
  • Diabetes Mellitus, Experimental* / metabolism
  • Diabetes Mellitus, Experimental* / pathology
  • Diabetes Mellitus, Type 2* / diet therapy
  • Diabetes Mellitus, Type 2* / metabolism
  • Diabetes Mellitus, Type 2* / pathology
  • Diet*
  • Female
  • Kidney Diseases* / diet therapy
  • Kidney Diseases* / metabolism
  • Kidney Diseases* / pathology
  • Male
  • Obesity* / diet therapy
  • Obesity* / metabolism
  • Obesity* / pathology
  • Proton Magnetic Resonance Spectroscopy* / methods
  • Random Allocation
  • Swine
  • Triglycerides / metabolism

Substances

  • Triglycerides