OBJECTIVEThis mechanistic trial compared the pharmacodynamics and safety of lixisenatide and liraglutide in combination with optimized insulin glargine with/without metformin in type 2 diabetes (T2D). RESEARCH DESIGN AND METHODSThis was a multicenter, randomized, open-label, three-arm trial comparing lixisenatide 20 mg and liraglutide 1.2 and 1.8 mg once daily for 8 weeks in combination with insulin glargine after optimized titration. The primary end point was change from baseline to week 8 in incremental area under the postprandial plasma glucose curve for 4 h after a standardized solid breakfast (AUC PPG 0030-0430 h ). Changes from baseline in gastric emptying, 24-h plasma glucose profile, HbA 1c , fasting plasma glucose (FPG), 24-h ambulatory heart rate and blood pressure, amylase and lipase levels, and adverse events (AEs) were also assessed. 2) h · mg/dL] vs. liraglutide 1.8 mg; P < 0.001 for both), and gastric emptying was delayed to a greater extent than with liraglutide 1.2 and 1.8 mg (P < 0.001 for treatment comparisons). FPG was unchanged in all treatment arms. At week 8, mean 6 SD HbA 1c was 6.2 6 0.4% (44 6 5 mmol/mol), 6.1 6 0.3% (44 6 4 mmol/mol), and 6.1 6 0.3% (44 6 4 mmol/mol) for lixisenatide 20 mg and liraglutide 1.2 and 1.8 mg, respectively. At week 8, both liraglutide doses increased marginal mean 6 SE 24-h heart rate from baseline by 9 6 1 bpm vs. 3 6 1 bpm with lixisenatide (P < 0.001). Occurrence of symptomatic hypoglycemia was higher with lixisenatide; gastrointestinal AEs were more common with liraglutide. Lipase levels were significantly increased from baseline with liraglutide 1.2 and 1.8 mg (marginal mean 6 SE increase 21 6 7 IU/L for both; P < 0.05). CONCLUSIONSLixisenatide and liraglutide improved glycemic control in optimized insulin glargine-treated T2D albeit with contrasting mechanisms of action and differing safety profiles.

OBJECTIVEIn patients with type 2 diabetes, glucagon levels are often increased. Furthermore, pulsatile secretion of insulin is disturbed in such patients. Whether pulsatile glucagon secretion is altered in type 2 diabetes is not known.RESEARCH DESIGN AND METHODSTwelve patients with type 2 diabetes and 13 nondiabetic individuals were examined in the fasting state and after mixed meal ingestion. Deconvolution analyses were performed on insulin and glucagon concentration time series sampled at 1-min intervals.RESULTSBoth insulin and glucagon were secreted in distinct pulses, occurring at ∼5-min intervals. In patients with diabetes, postprandial insulin pulse mass was reduced by 74% (P < 0.001). Glucagon concentrations were increased in the patients during fasting and after meal ingestion (P < 0.05), specifically through an increased glucagon pulse mass (P < 0.01). In healthy subjects, the increase in postprandial insulin levels was inversely related to respective glucagon levels (P < 0.05). This relationship was absent in the fasting state and in patients with diabetes.CONCLUSIONSGlucagon and insulin are secreted in a coordinated, pulsatile manner. A plausible model is that the postprandial increase in insulin burst mass represses the corresponding glucagon pulses. Disruption of the insulin–glucagon interaction in patients with type 2 diabetes could potentially contribute to hyperglucagonemia.

OBJECTIVEβ-Cell mass declines progressively during the course of diabetes, and various antidiabetic treatment regimens have been suggested to modulate β-cell mass. However, imaging methods allowing the monitoring of changes in β-cell mass in vivo have not yet become available. We address whether pancreatic β-cell area can be assessed by functional test of insulin secretion in humans.RESEARCH DESIGN AND METHODSA total of 33 patients with chronic pancreatitis (n = 17), benign pancreatic adenomas (n = 13), and tumors of the ampulla of Vater (n = 3) at various stages of glucose tolerance were examined with an oral glucose load before undergoing pancreatic surgery. Indexes of insulin secretion were calculated and compared with the fractional β-cell area of the pancreas.RESULTSβ-Cell area was related to fasting glucose concentrations in an inverse linear fashion (r = −0.53, P = 0.0014) and to 120-min postchallenge glycemia in an inverse exponential fashion (r = −0.89). β-Cell area was best predicted by a C-peptide–to–glucose ratio determined 15 min after the glucose drink (r = 0.72, P < 0.0001). However, a fasting C-peptide–to–glucose ratio already yielded a reasonably close correlation (r = 0.63, P < 0.0001). Homeostasis model assessment (HOMA) β-cell function was unrelated to β-cell area.CONCLUSIONSGlucose control is closely related to pancreatic β-cell area in humans. A C-peptide–to–glucose ratio after oral glucose ingestion appears to better predict β-cell area than fasting measures, such as the HOMA index.