[1646] Hyaline Arteriolosclerosis in Glomerular Afferent and Efferent Arterioles: Are the Deposits Hard or Soft, Stationary or Mobile?

L Clarke Stout, Jr., Jennifer Ross. University of Texas Medical Branch, Galveston, TX; Methodist Hospital, Houston, TX

Background: Hyaline deposits (HD) in glomerular afferent (AA) and efferent (EA) arterioles (the latter being unique to diabetes) are thought to cause glomerular occlusion in diabetic nephropathy and possibly hypertension. This requires HD to be rigid and accumulate over time, but our studies in 25 diabetics and 14 controls suggest they are compressible and mobile. We also found HD in EA in 15% of controls showing that serial paraffin sections can reveal new facts about HD. Furthermore, 2 diabetics and 4 controls also had PolyBed 812 embedded toluidine blue (TB) stained 1μ serial sections that exposed smaller HD not seen in paraffin sections (unpublished observations). One such 19 yr old male control had even more HD, apparently from hypotension due to a torn kidney in an auto accident. He was stable after kidney resection with normal urine output for 7 days when life support was withdrawn due to brain damage, thus allowing comparison of size and location of HD in resected kidney (Rkid) versus autopsy kidney (Akid). Standard stains of 1μ sections confirmed that TB stains accurately reflected HD morphology.
Design: HD were compared in 1μ serial sections of 15 complete glomeruli from each kidney. HD were called small, medium or large according to how many thirds of wall width were involved. Mean HD length was measured in μ, and mean % of wall circumference with HD was estimated to the nearest eighth (22.5 °).
Results: Mean number of glomeruli with HD in AA, EA, and Bowman's capsule/either convoluted tubule wall was 15/14/9 in Rkid and 9/9/3 in Akid. Mean length (μ) of HD in AA/EA was 17.3/23.9 in Rkid and 12.3/17.6 in Akid. Mean circumference of wall (%) with HD in AA/EA was 27/56.8 in Rkid and 25.6/33.3 in Akid. % of large HD in AA/EA was 53/50 in Rkid and 33/33 in Akid. HD in Bowman's capsule/either convoluted tubule wall were found at the vascular pole, often near HD in AA or EA. Exam of 100 glomeruli in PAS stained 2μ paraffin sections in Rkid found 3 HD in AA and 1 HD in EA. No HD were noted in surg path or autopsy reports of Rkid and Akid.
Conclusions: The relatively simple 1μ serial sections revealed far more HD than were previously known to exist. HD were seen in almost every glomerulus in 1 transiently hypotensive control Rkid despite being absent in surg path reports. The number and size of these HD in Rkid were reduced by about 1/3 in Akid after 7 days of hemodynamic stability, suggesting rapid movement of HD through interstitial spaces.
Category: Kidney (does not include tumors)

Monday, March 4, 2013 1:00 PM

Poster Session II # 243, Monday Afternoon

 

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