Abstract: TH-PO1085
Rapid Progression of Glomerulosclerosis due to Concurrent Diabetes and Hypertension Correlates with Podocyte Damage Shown by Expansion Microscopy
Session Information
- Glomerular Diseases: Podocyte Biology - I
November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1204 Podocyte Biology
Authors
- Kuzay, Yalcin, University Heidelberg, Mannheim, BW, Germany
- Clark, Euan, University Heidelberg, Mannheim, BW, Germany
- Medina balbuena, Sara, V Medical Clinic, University Heidelberg, Mannheim, Germany
- Yard, Benito, V Medical Clinic, University Heidelberg, Mannheim, Germany
- Mullins, John, University of Edinburgh, Edinburgh, United Kingdom
- Kriz, Wilhelm, University Heidelberg, Mannheim, Germany
- Gröne, Hermann-Josef, university of Marburg, Paderborn, Germany
- Hoffmann, Sigrid C., University Heidelberg, Mannheim, BW, Germany
Background
Glomerulosclerosis is a hallmark of diabetes (D) and hypertension (HT) induced kidney failure. Here we studied the combined effect of D-HT on the kidney using expansion microscopy for nanoscale imaging of podocyte foot processes (FP).
Methods
In 6-week-old male double transgenic rats (dTGRNeph-hAT1R;Cyp1a1mRen2dF1=dTGR) and TGRCyp1a1mRen2d (TGR) we induced for 8 weeks D by streptozotocin (60mg/kg i.p.) and HT by indol-3-carbinol (0.0125% in chow), alone or in combination (D-HT). After perfusion with 2%PFA, kidneys were ~4.5 times expanded using acrylamide/sodium-acrylate gel embedding, SDS/75°C+90°C denaturation, podocin immunohistochemistry and imaging by confocal microscopy after expansion in H2O. We measured FP width as the distance between two podocin signals and normalized for the expansion factor.
Results
D-HT-WT rats developed massive albuminuria (D-HT 240mg vs HT 20mg, controls 1.5 mg per 24hr) and a drop in GFR (D-HT: 4-fold, HT: 1.6 fold vs. controls), which correlated with histological alterations in glomeruli, including mesangial expansion, podocyte loss and adhesion of the glomerular tuft to the Bowman’s capsule. HT rats showed very mild histological injury. D rats did not differ from controls. AT1R overexpression in podocyte aggravated the glomerular damage, drop in renal function in HT and D-HT but did not affect controls. Glomerular size increased similarly in both HT and D-HT and did not differ between dTGR and TGR. In dTGR- and TGR-controls, podocyte FP architecture was regular with long thin processes (200±20 nm width). In HT, FP were homogenously shortened and widened. In D-HT, FP structure within one glomerulus varied from regular with shortened and widened FP to irregular structures to regions with total loss of FP (average FP width 400±20 nm).
Conclusion
In contrast to D and HT, combined HT+D induced rapid progression of glomerulosclerosis and podocyte damage. Podocyte’s AT1Rs aggravate damage index. ExM enabled visualization of nanoscale alterations in FPs in 3-D by using traditional immunohistochemistry and confocal microscopy. Acknowledgements: This study was funded by DFG, CRC 1118 to SH