Photodynamic diagnostics of early gastric cancer: Complexity measures of gastric microcirculation and new model of metastatic adenocarcinoma of rat stomach

Abstract

The detection of early gastric cancer that often develops asymptomatically is crucial for improving patient survival. The photodynamic diagnosis (PDD) of gastric cancer using 5-aminolevulinic acid/protoporphyrin IX (5-ALA/PpIX) has been reported in several studies. However, the selectivity of PDD of gastric tumor is poor with often false-positive results that require the development of new methods to improve PDD for early gastric cancer. Therefore, a measure of the complexity of gastric microcirculation (multi-scale entropy, MSE) and the detrended fluctuation analysis (DFA) were applied as additional tools to detect early gastric cancer in rats.In this experimental study, we used our original model of metastatic adenocarcinoma in the stomach of a rat. To induce a gastric tumor, we used a long-term combination (for 9 months, which is 1/2 of the life of rats) of two natural factors, such as chronic stress (overpopulation being typical for modern cities) and the daily presence of nitrites in food and drinks, which are common ingredients added to processed meat and fish to help preserve food. Our results clearly show that both methods, namely, PDD using 5-ALA/PpIX and complexity/correlation analysis, can detect early gastric cancer, which was confirmed by histological analysis. Pre-cancerous areas in the stomach were detected as an intermediate fluorescent signal or MSE level between normal and malignant lesions of the stomach. However, in some cases, PDD with 5-ALA/PpIX produced a false-positive fluorescence of exogenous fluorophores due to its accumulation in benign and inflammatory areas of the mucosa. This fact indicates that the PDD itself is not sufficient for the correct diagnosis of gastric cancer, and the use of additional characteristics, e.g., complexity measures or scaling exponents, can significantly improve the diagnostic accuracy of PDD of gastric cancer that should be confirmed in further clinical studies and applications.

A review of career devoted to Biophotonics – In memoriam to Ekaterina Borisova (1978–2021)

“…Her work included the investigation of novel photosensitizers and the optimal parameters for their irradiation and photodynamic activation [48][49][50][51][52][53][54][55][56][57]. As a result, significant amount of her work was dedicated to the photodynamic diagnosis [48,58], photodynamic efficacy [59] and therapy as well [60][61][62][63].…”

Phenomenon of atypical vascular effects of epinephrine and an increase of photodynamic response by nitroglycerin in rats with colon adenocarcinoma: adrenergic and nitrergic mechanisms and novel applied aspects

“…To induce GI cancer, the rats underwent to a long term combination (during 9 months) of social stress (overpopulation) and daily diet including of toluidine (2 g/kg) in food and water with nitrites (2 g/l). In our previous work we studied formation of stress-induced gastric adenocarcinoma [23]. Here, we focused on the study of stress-induced colon cancer development (highly differentiated adenocarcinoma).…”