Metabolism and Microstructure of the Small Intestine Wall in Patients With Colorectal Cancer

RELEVANCE In patients with colorectal cancer (CRC), the normal small intestine, located outside the pathological focus, undergoes changes that may be the cause of digestive dysfunction after radical surgery to remove the tumor. The assessment of metabolic and microstructural changes in the ileum mucosa in patients with colorectal cancer is necessary to correct the algorithms of postoperative therapy and enteral nutrition. Modern means of optical bioimaging are potentially capable of solving this complex diagnostic problem. AIM OF STUDY To study the features of metabolism and morphological structure of the wall of a conditionally normal small intestine in the mucosa in patients with stage 1–3 CRC using macro- FLIM and optical coherence tomography (OCT). MATERIAL AND METHODS The object of the study was the wall of the ileum (66 samples) from the mucosal side of patients with histologically confirmed CRC stages 1–3 with tumor location in the right sections of the colon. Eight samples were obtained from patients with stage 1 CRC, 38 samples were obtained from patients with stage 2 and 20 samples were obtained from patients with stage 3 tumor. The volume of surgical intervention is right-sided hemicolectomy with total mesocolonectomy, CME (D2 lymph node dissection). Fresh tissue samples were examined using fluorescent lifetime macroimaging (macro-FLIM ) and OCT, followed by histological analysis of the material. RESULTS According to a histological study in the small intestine of patients with stage 1 CRC, the mucosa is covered with a normal single-layer prismatic border epithelium. In the intestine samples of patients with stage 2 CRC, mucus hypersecretion with areas of fibrosis and vascular congestion was observed. At the 3rd stage of CRC, the mucous membrane of the small intestine was loose, with local thickenings, areas of fibrosis with severe leukostasis, and foci of atrophy. None of the samples showed histological signs of a malignant tumor. According to OCT data, in the mucous membrane of the small intestine in patients with the 1st and 2nd stages of CRC, the contours of the villi and, partially, the crypts were well visualized. The structure of the villi was smooth, not coarse, and the shape was regular. In patients with stage 3 CRC, the contours of the crypts and villi were indistinct. There were no differences in the OCT picture between histologic preparations in the 1st and 2nd stages of CRC: the structure of the villi of the small intestine was clear