Purpose We assessed whether phosphodiesterase-III inhibition with cilostazol (Cil) augments the infarct size (IS)-limiting effects of MK0626 (MK), a dipeptidyl-peptidase-4 (DPP4) inhibitor, by increasing intracellular cAMP in mice with type-2 diabetes. Methods Db/Db mice received 3-day MK (0, 1, 2 or 3 mg/kg/d) with or without Cil (15 mg/kg/d) by oral gavage and were subjected to 30 min coronary artery occlusion and 24 h reperfusion. Results Cil and MK at 2 and 3 mg/kg/d significantly reduced IS. Cil and MK had additive effects at all three MK doses. IS was the smallest in the MK-3+Cil. MK in a dose dependent manner and Cil increased cAMP levels (p0.001). cAMP levels were higher in the combination groups at all MK doses. MK-2 and Cil increased PKA activity when given alone; however, PKA activity was significantly higher in the MK-2+Cil group than in the other groups. Both MK-2 and Cil increased myocardial levels of Ser133 P-CREB, Ser523 P-5-lipoxygenase, Ser473P-Akt and Ser633 P-eNOS. These levels were significantly higher in the MK-2+Cil group. Myocardial PTEN (Phosphatase and tensin homolog on chromosome ten) levels were significantly higher in the Db/Db mice compared to nondiabeticmice.MK- 2 and Cil normalized PTEN levels. PTEN levels tended to be lower in the combination group than in the MK and Cil alone groups. Conclusion MK and Cil have additive IS-limiting effects in diabetic mice. The additive effects are associated with an increase in myocardial cAMP levels and PKA activity with downstream phosphorylation of Akt, eNOS, 5-lipoxygenase and CREB and downregulation of PTEN expression.
- CAMP-protein kinase A
- Diabetes mellitus
- Infarct size
- Phosphodiesterase-III inhibitor
ASJC Scopus subject areas
- Pharmacology (medical)
- Cardiology and Cardiovascular Medicine
Phosphodiesterase III Inhibition Increases cAMP levels and augments the infarct size limiting effect of a dpp-4 inhibitor in mice with type-2 diabetes mellitus. / Birnbaum, Yochai; Castillo, Alexander C.; Qian, Jinqiao; Ling, Shukuan; Ye, Hongmei; Perez-Polo, Jose R.; Bajaj, Mandeep; Ye, Yumei.In: Cardiovascular Drugs and Therapy, Vol. 26, No. 6, 12.2012, p. 445-456.
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