Evans blue-mediated white-light detection of non-muscle-invasive bladder cancer: A preclinical feasibility and safety study using a rat bladder urothelial cell carcinoma model

Abstract

Photodynamic diagnosis (PDD) improves the detection of non-muscle-invasive bladder cancer (NMIBC). However, white-light (WL) cystoscopy remains the technique routinely used in urological clinics. A more cost-effective but equally performant alternative to PDD may encompass the use of an intense tumoritropic dye in combination with WL cystoscopy. Using a preclinical setting, we investigated the practical aspects of the use of Evans blue (EB) dye for the possible future detection of NMIBC using WL cystoscopy. A solution of 1 and 5 mM EB was instilled into healthy and AY-27 tumor-bearing rat bladders. The bladders were then rapidly dissected and the inner walls were inspected for EB using WL stereomicroscopy. EB present in the bladders and the plasma was also quantified using high performance liquid chromatography. To assess the effects of repeated instillations on normal rat bladders, EB was instilled for 7 consecutive days, after which time the bladder wall was investigated histologically. To gain insight into the mechanisms underlying the selective accumulation of EB in malignant urothelium, RNA sequencing of urothelial tissue and subsequent comparative analysis were performed, with a specific focus on cell adhesion. The concentrations of EB were substantially higher in malignant bladders compared with those in healthy bladders, matching the blue staining of the inner bladder wall observed by stereomicroscopy. EB was equally present in the plasma of healthy and tumor-bearing subjects, although at low concentrations. Importantly, EB did not cause any abnormalities in the urothelium after 7 days of repeated instillation in normal rats. RNA sequencing of the urothelium indicated an abnormal expression of several genes related to cell adhesion in malignant urothelium compared with the normal urothelium. Our findings may be important for future clinical developments in the field of diagnostics for bladder cancer. Implementing the more cost-effective protocol of EB instillations in combination with WL cystoscopy may offer a benefit to patients as well as the healthcare system.

Functional and histologic imaging of urinary bladder wall after exposure to psychological stress and protamine sulfate

“…The passive, concentration dependent, paracellular diffusion of instilled Gadobutrol 29 (604.71 Daltons), cations 10 and of large molecular weight permeability probes such Evans blue dye (961 Daltons) 17 , 45 into bladder mucosa led us to infer that the compromised mucosal barrier increases the penetration of irritants from urine for inciting the underlying afferent nerves and drive the pain and LUTS of IC/BPS patients. Thus, a significant rise in [Gd] ingress after PS exposure in the WAS group can potentially replicate the flare up of BPS/IC symptoms 46 in a non-infective rodent model without relying on bacterial products.…”

Intravesical Contrast-Enhanced MRI: A Potential Tool for Bladder Cancer Surveillance and Staging

“…Instilled GBCA is unlikely to enter umbrella cells as the transcellular permeability of umbrella cells is restricted, and GBCA is unable to enter even red blood cells upon injection [90]. The perturbed tight junctions [67,85] of cancer foci are known to compromise the urothelial barrier, which accentuates the passive diffusion of instilled GBCA in both rodent (Figure 5) [63,65,70,77] and human bladder (Figures 2 and 3) [55], analogous to the diffusion of instilled polar dyes in preclinical [91][92][93] and clinical [86][87][88][89] studies. The differential signal enhancement of cancer foci by ICE-MRI replicates the results obtained with other radiation-free approaches [58,86].…”

“…Given that the physical gap of the apico-lateral tight junction [91,92,94] (Figures 2 and 3) can be partly mimicked by the pore size of 12% polyacrylamide gel [95], we relied on that equivalence to study the paracellular diffusion [31] of Gadobutrol without the confounding influence (Figure 6) of bladder distension and bladder perfusion [84,96]. A spherical bladder-shaped cavity was molded with 12% polyacrylamide gel poured into a plastic container, which was wrapped by a 4-channel flexible receiver coil, for image acquisition using a multi-echo spoiled-gradient echo pulse sequence in 3T scanner (Siemens, BioGraph) Figure 6.…”

Photodynamic Therapy for Bladder Cancers, A Focused Review†

“…Apart from these concerns, FLC requires an upfront cost of sophisticated machinery and personnel training (88). Recently, another cost‐effective approach was tried in a rat bladder tumor model where Evans blue 1 and 5 m m were instilled in the rat bladder and found that Evans blue was selectively taken up by the tumor tissue in the malignant bladder compared with the healthy bladder (107) (Table 2).…”