Cytochrome P450 epoxygenase-derived epoxyeicosatrienoic acids contribute to insulin sensitivity in mice and in humans

• Published in: Diabetologia 2017-06, Vol.60 (6), p.1066-1075
• Main Authors: Gangadhariah, Mahesha H., Dieckmann, Blake W., Lantier, Louise, Kang, Li, Wasserman, David H., Chiusa, Manuel, Caskey, Charles F., Dickerson, Jaime, Luo, Pengcheng, Gamboa, Jorge L., Capdevila, Jorge H., Imig, John D., Yu, Chang, Pozzi, Ambra, Luther, James M.
• Format: Article
• Language: English
• Subjects: Animals; Arachidonic acid; Blood pressure; Cytochrome; Cytochrome P-450 Enzyme System - genetics; Cytochrome P-450 Enzyme System - metabolism; Cytochrome P450; Cytochrome P450 Family 2 - genetics; Cytochrome P450 Family 2 - metabolism; Diabetes mellitus; Eicosanoids - metabolism; Glucose; Glucose tolerance; Homeostasis; Human Physiology; Hypertension; Hypotheses; Insulin; Insulin resistance; Insulin Resistance - genetics; Insulin Resistance - physiology; Internal Medicine; Intravenous administration; Islets of Langerhans - metabolism; Male; Mass spectroscopy; Medicine; Medicine & Public Health; Mesenteric Arteries - metabolism; Metabolic Diseases; Mice; Muscle contraction; Musculoskeletal system; Rodents; Secretion; Skeletal muscle
• ISSN: 0012-186X; 1432-0428; 1432-0428
• DOI: 10.1007/s00125-017-4260-0

Aims/hypothesis Insulin resistance is frequently associated with hypertension and type 2 diabetes. The cytochrome P450 (CYP) arachidonic acid epoxygenases (CYP2C, CYP2J) and their epoxyeicosatrienoic acid (EET) products lower blood pressure and may also improve glucose homeostasis. However, the direct contribution of endogenous EET production on insulin sensitivity has not been previously investigated. In this study, we tested the hypothesis that endogenous CYP2C-derived EETs alter insulin sensitivity by analysing mice lacking CYP2C44, a major EET producing enzyme, and by testing the association of plasma EETs with insulin sensitivity in humans. Methods We assessed insulin sensitivity in wild-type (WT) and Cyp2c44 −/− mice using hyperinsulinaemic–euglycaemic clamps and isolated skeletal muscle. Insulin secretory function was assessed using hyperglycaemic clamps and isolated islets. Vascular function was tested in isolated perfused mesenteric vessels. Insulin sensitivity and secretion were assessed in humans using frequently sampled intravenous glucose tolerance tests and plasma EETs were measured by mass spectrometry. Results Cyp2c44 −/− mice showed decreased glucose tolerance (639 ± 39.5 vs 808 ± 37.7 mmol/l × min for glucose tolerance tests, p  = 0.004) and insulin sensitivity compared with WT controls (hyperinsulinaemic clamp glucose infusion rate average during terminal 30 min 0.22 ± 0.02 vs 0.33 ± 0.01 mmol kg −1  min −1 in WT and Cyp2c44 −/− mice respectively, p  = 0.003). Although glucose uptake was diminished in Cyp2c44 −/− mice in vivo (gastrocnemius R g 16.4 ± 2.0 vs 6.2 ± 1.7 μmol 100 g −1  min −1 , p