Treatment of type 1 diabetic patients with glucagon-like peptide-1 (GLP-1) and GLP-1R agonists.

GLP-1 (glucagon-like peptide-1) is a peptide hormone secreted from endocrine cells in the intestinal mucosa in response to meals. The major effects of GLP-1 are to increase glucose-induced insulin secretion and reduce glucagon re- lease, but GLP-1 also inhibits gastric emptying rate and reduces appetite and bodyweight in obese subjects. In vivo studies using animal models of type 2 diabetes and in vitro studies using human islet cells have suggested that GLP-1 or GLP-1 analogues are also able to increase s-cell mass, but in animal models of type 1 diabetes, there is much less evidence for a s-cell preserving effect. This review summarizes the present knowledge of GLP-1 and its analogues regarding its role as a possible treatment in patients with type 1 diabetes. The studies that address the effect of GLP-1 and GLP-1 analogues on s-cell mass in both type 2 and type 1 diabetes, as well as the potential of GLP-1 as an adjuvant therapy in islet cell trans- plantation, will be reviewed. Suggestions for future studies of GLP-1 treatment in type 1 diabetes may include early treatment in order to preserve s-cell mass and prolong the remission period, but should also take a potential insulin spar- ing effect and changes in the risk of hypoglycemia into account.