Background, methods: Here we investigated the effects of long-term treatment with empagliflozin, a sodium
glucose cotransporter-2 (SGLT-2) inhibitor in clinical development, alone and in combination
with the DPP-4 inhibitor linagliptin (LINA; approved antidiabetes drug) on whole body
and organ-specific insulin sensitivity in db/db mice using euglycemic-hyperinsulinemic
clamps.
Results: In 8-week old female db/db mice (n = 15/group) treated for 8 weeks, the glucose disposal
rate was improved in the 10 mg/kg/d EMPAGLIFLOZIN group (5.9 mg/kg/min; p < 0.001),
the 3 mg/kg/d LINA group (3.4 mg/kg/min; p < 0.01) and the EMPAGLIFLOZIN+LINA group
(combination 10 mg/kg/d EMPAGLIFLOZIN plus 3 mg/kg/d LINA; 7.8 mg/kg/min; p < 0.001)
compared with vehicle (1.9 mg/kg/min). Insulin-mediated suppression of hepatic glucose
production (HGP) was significantly (p < 0.05) higher in the EMPAGLIFLOZIN (13.1 mg/kg/min)
and EMPAGLIFLOZIN+LINA groups (11.8 mg/kg/min) compared with vehicle (26.3 mg/kg/min).
LINA monotherapy improved HGP (21.8 mg/kg/min), although statistical significance
was not achieved.
issue-specific labeled glucose uptake was higher in liver and kidney with EMPAGLIFLOZIN
(liver: 822 dpm/g/ml; kidney: 1580 dpm/g/ml; p < 0.05 for both), LINA (liver: 935
dpm/g/ml; kidney: 1660 dpm/g/ml; p < 0.05 for both) and EMPAGLIFLOZIN+LINA (liver:
1040dpm/g/ml; kidney: 2190dpm/g/ml; p < 0.01 for both) compared with vehicle (liver:
610dpm/g/ml; kidney: 1030dpm/g/ml). Glucose uptake into muscle and adipose tissue
was not affected by any treatment. Improvements in liver triglyceride content were
also shown with EMPAGLIFLOZIN (9.1%; p < 0.05), LINA (12.1%; p < 0.01) and EMPAGLIFLOZIN+LINA
(5.7%; p < 0.01) compared with vehicle (14.6%).
Conclusion: In conclusion, EMPAGLIFLOZIN+LINA is superior to the respective monotherapies in
improving insulin sensitivity, in particular, during conditions of severe insulin
resistance.