Glucose diffusion in colorectal mucosa—a comparative study between normal and cancer tissues

Abstract

Colorectal carcinoma is a major health concern worldwide and its high incidence and mortality requireaccurate screening methods. Following endoscopic examination, polyps must be removed for histopathologicalcharacterization. Aiming to contribute to the improvement of current endoscopy methods of colorectal carcinomascreening or even for future development of laser treatment procedures, we studied the diffusion properties ofglucose and water in colorectal healthy and pathological mucosa. These parameters characterize the tissuedehydration and the refractive index matching mechanisms of optical clearing (OC). We used ex vivo tissuesto measure the collimated transmittance spectra and thickness during treatments with OC solutions containingglucose in different concentrations. These time dependencies allowed for estimating the diffusion time and diffusioncoefficient values of glucose and water in both types of tissues. The measured diffusion times for glucosein healthy and pathological mucosa samples were 299.2+/-4.7 s and 320.6+/-10.6 s for 40% and 35% glucoseconcentrations, respectively. Such a difference indicates a slower glucose diffusion in cancer tissues, whichoriginate from their ability to trap far more glucose than healthy tissues. We have also found a higher freewater content in cancerous tissue that is estimated as 64.4% instead of 59.4% for healthy mucosa.