Introduction:
Gastrointestinal mucositis (GIM) is a severe and debilitating side-effect of cancer therapy. There are currently few treatments which effectively prevent or ameliorate GIM. In a previous study it was shown that elsiglutide, a selective glucagon-like peptide-2 (GLP-2) receptor agonist, improved diarrhoea and histological damage associated with irinotecan-induced GIM in a rat model. Increased apoptosis, inflammation and decreased proliferation are associated with irinotecan-induced GIM. It is thought that elsiglutide may improve diarrhoea and damage through altering these gastrointestinal cellular effects.
Objectives:
To determine if elsiglutide reduces apoptosis and inflammation, and increases proliferation in the small intestinal crypts of the rat, following irinotecan administration.
Method:
Dark Agouti rats were given irinotecan once (200mg/kg, 0 hrs) and elsiglutide (0.9mg/kg or 1.8mg/kg per day, subcutaneous) for 5 days, and killed at 6, 72 or 120 hrs (n=6). Markers for apoptosis (Caspase-3), proliferation (Ki67) and inflammation (myeloperoxidase, MPO) were analysed using immunohistochemistry in the jejunum and ileum. Positive stained cells were counted per crypt or field of view (FOV).
Results:
Apoptosis was significantly (p<0.05, cells/crypt) reduced following 0.9mg/kg/day elsiglutide and irinotecan at 6hrs (Jejunum 10.15±1.00; Ileum 13.85±1.44) compared with irinotecan control (Jejunum 14.84±1.15; Ileum 22.49±1.08). Proliferation was significantly (p<0.05, cells/demi-crypt) increased at 72hrs (peak damage) in this group (Jejunum 31.45±2.78; Ileum 28.47±2.64) compared with irinotecan alone (Jejunum 18.98±2.13; Ileum 18.64±1.62). Staining also showed that 0.9mg/kg/day elsiglutide given after irinotecan significantly (p<0.01, cells/FOV) reduces the number of MPO positive inflammatory cells in the jejunum (72hrs 67.02±6.72; 120hrs 42.08±5.52) compared with irinotecan alone (72hrs 106.69±6.04; 120hrs 64.30±7.65).
Conclusions:
Elsiglutide (0.9mg/kg/day) decreases apoptosis and inflammation, which may be contributors to irinotecan-induced GIM. In addition, elsiglutide improves proliferation of crypt cells, which may shorten the duration of GIM. These results provide a basis for future studies with elsiglutide to determine the exact mechanisms for this phenomenon.