Abstract
BackgroundThe aim of the present in vitro study was to investigate, in different genders, motor responses in surgical colonic specimens from patients with rectal cancer undergoing and not undergoing chemotherapy with capecitabine and radiotherapy.MethodsThis in vitro study was conducted from October 2015 to August 2017 at the Experimental Pharmacology Laboratory at the National Institute “S. de Bellis” after collecting samples at the Department of Surgery. Segments of sigmoid colon were obtained from 15 patients (Male (M)/Female (F) = 8/7; control group, CG) operated on for elective colorectal resection for rectal cancer without obstruction and 14 patients (M/F = 7/7; study group, SG) operated on for elective colorectal resection for rectal cancer who also received chemotherapy, based on capecitabine twice daily, and radiotherapy. Isometric tension was measured on colonic circular muscle strips exposed to increasing carbachol or histamine concentrations to obtain concentration-response curves. The motor responses to electrically evoked stimulation were also investigated.ResultsIn males, carbachol and histamine caused concentration-dependent contractions in the CG and SG. An increased sensitivity and a higher response to carbachol and histamine were observed in SG than CG (P < 0.01). On the contrary, in females, the response to carbachol was not significantly different in CG from the SG and the maximal responses to carbachol were greater in CG than in SG (P < 0.001). The same applied to histamine for half-maximal effective concentrations and maximal response in that they were not significantly different in CG from the SG. Electrically evoked contractions were significantly more pronounced in males, especially in the SG (P < 0.05).ConclusionsThis preliminary in vitro study has shown gender differences in motor responses of colonic circular muscle strips in patients who had received chemotherapy with capecitabine and radiotherapy.
Highlights
The aim of the present in vitro study was to investigate, in different genders, motor responses in surgical colonic specimens from patients with rectal cancer undergoing and not undergoing chemotherapy with capecitabine and radiotherapy
Segments of sigmoid colon obtained from 15 patients (M/F = 8/7) operated on for elective colorectal resection for rectal cancer served as a control group (CG) and 14 patients (M/F = 7/7) operated on for elective colorectal resection of rectal cancer who had received neoadjuvant therapy, based on capecitabine (Xeloda®, 825 mg/m2, Welwyn Garden City, United Kingdom), twice daily and one dose of radiotherapy (50.4 Gy in 28 fractions of 180 cGy/die) before surgery served as a study group (SG)
EC50 values to carbachol were 8.54 × 10−6M and 1.58 × 10−6M in CG and SG respectively (Fig. 1)
Summary
The aim of the present in vitro study was to investigate, in different genders, motor responses in surgical colonic specimens from patients with rectal cancer undergoing and not undergoing chemotherapy with capecitabine and radiotherapy. Some authors have shown hypercontractility in gastric fundic and duodenal muscle in rats after exposure to Fluorouracil (5-FU) [4] while others have found increased sensitivity to cholinergic stimulation in the duodenum and colon after whole-body irradiation in guinea pigs [4, 5]. This increased responsiveness after irradiation may be associated with colonic motor alterations consisting in giant contractions in dogs and intestinal migrating motor complexes disruption in rats [2, 6].
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