Fig 1.
TEM of control specimens revealed 3–6 cell layers in the urothelium (A, bar: 10um) with intact umbrella cells (B, bar: 10um) and anchoring junctions such as desomosomes. (C, bar:500nm). SEM also revealed intact umbrella cells with uniform cell size (D, bar: 10um). The microplicae in the umbrella cells was also intact (E, bar: 5um and F, bar: 1um).
Fig 2.
TEM for IC/BSP bladder samples.
TEM of IC/BPS samples from patients with different symptom severity showed variable findings. In some IC/BPS patients, normal cell layers in the urothelium and intact, anchoring junctions were found (A, bar: 10um and B, bar:500nm). However, most IC/BPS patients had urothelial defects on TEM. Decreased cell layers (C, bar: 10um), denudation of umbrella cells (D, arrowheads, bar: 10um), and widening of lateral interstitial space between adjacent umbrella cells were noted in most patients (E, bar:500nm). In patients with severe ulcerous IC/BPS, only a few basal cells could be found in the urothelium (F, bar:10um).
Fig 3.
SEM for IC/BPS bladder samples.
SEM of IC/BPS specimens showed umbrella cell pleomorphism (A, bar: 40um) and denudation with intermediate cell exposure (B, arrowhead, bar: 100um). In some severe IC/BPS, totally denudation of urothelium with exposed basement membrane was observed (C,bar 20um). In some patients, microplicae of the umbrella cell membranes was only mild decreased (D, bar: 2um), but most patients had moderate to severe decreases of microplicae (E, bar: 2um and F, bar: 5um).
Table 1.
Summary of clinical parameters and grading of electron microscopy (EM) findings in IC/BPS and control patients.
Table 2.
Comparison of urothelium EM defect findings between IC/BPS and control patients.
Fig 4.
IC/BPS symptom parameters for the various EM finding severities.
The patients with moderate to severe defects of umbrella cell integrity on TEM had significantly more severe VAS pain scores and smaller MBCs (both p = 0.010, Mann–Whitney U test). Patients with moderate to severe defects of microplicae in the cell membrane on SEM had significantly smaller CBCs and MBCs (p = 0.037 and 0.047, respectively, Mann–Whitney U test).
Fig 5.
Novel TEM findings in IC/BPS urothelium.
(A) red blood cells extravasation (black arrows) from lamina propria to urothelium with interrupted basement membrane (arrowheads, bar: 10um). This bladder specimen was obtained before hydrodistention. (B) Macrophage in the urothelium (arrowhead, bar: 2um). (C) Widening of lateral interstitial space between adjacent umbrella cells s with loose interdigitation (black arrows, bar: 2um) in both umbrella and intermediate cells.