“Cilia Metaplasia” in Renal Transplant Biopsies with Acute Tubular Injury.
Harsha S Desai, Joseph P Roszka, Marie L Kaiser, Karen L Dundas, Michele T Rooney, Ping L Zhang. William Beaumont Hospital, Royal Oak, MI
Background: Primary cilia are hair-like organelles singly distributed along the apical surface of proximal and distal nephron tubules. They are known to play a mechanosensation role in tubular differentiation. A recent study demonstrated increased length of cilia in renal transplantation with acute tubular injury (ATI), using immunofluorescent method against alpha-tubulin, as an indicator of injury and repair (J Am Soc Nephrol 2009: 20: 2147-2153). In our study we used electron microscopy (EM) to evaluate cilia changes in acute tubular injury (ATI) in both transplant and native biopsies.
Design: Three groups of cases were included: control group 1- native biopsies without major changes in renal tubules; study group 2- native biopsies with prominent ATI, and study group 3- renal transplant biopsies with prominent ATI (delayed renal function group). Extensive search for ciliary structures along renal tubules (at least 10 15 fields at 6,500 magnification) was conducted in each case. When cilia were identified, high magnification (up to 130,000) was used to obtain images for detailed ultrastructural study. The search for cilia was focused on proximal tubular areas with injured (diminished) apical microvilli.
Results: Singly located cilia were found in 3/19 specimens in control group 1, 4/18 in group 2 (native ATI), and 6/24 in group 3 (transplant ATI). Importantly, there were clusters of cilia in proximal tubules with markedly diminished apical microvilli in 3/25 biopsies from two patients in group 3, but none from groups 1 and 2. The clusters of cilia ranged from 6 to 15 individual cilia along the apical surface with diminished apical microvilli.
Under high magnifications, the cilia demonstrated 9 pairs of peripheral microtubules without central two singlet microtubules, consistent with primary cilia (9 + 0) rather than motile cilia (9 + 2).
Conclusions: Using EM, we found clusters of cilia in proximal tubules with remarkable apical microvillar injury in 3 biopsies from renal transplants with ATI; we name this finding as “cilia metaplasia.” The “metaplastic” cilia are primary cilia (9 + 0) and may be an index for the repairing process.
Wednesday, March 2, 2011 9:30 AM
Poster Session V # 278, Wednesday Morning