Does Pioglitazone Increase the Production of 15-EPI-Lipoxin A4?

Summary

Type-2 diabetes mellitus is a public health concern. Patients with type 2 diabetes mellitus are at high risk of developing cardiovascular complications. Diabetic patients are two to four-times more likely to develope cardiovascular disease. The mortality of diabetic patients with cardiovascular disease is much higher than in non-diabetic matched patients with cardiovascular disease. Recently, it has become apparent that not all anti-diabetic drugs have the same effect on the progression of atherosclerosis and on cardiovascular outcomes. There is a great need to understand the potential protective mechanisms of the various anti-diabetic drugs in order to decrease their risk for cardiovascular morbidity and mortality. In addition to increasing insulin sensitivity, Pioglitazone (PIO) has anti-inflammatory properties. However, the underlying mechanisms of these anti-inflammatory (and probably anti-atherosclerotic) effects of PIO are unknown. We have shown in the rat that 3-day pretreatment with PIO increases myocardial cyclooxygenase-2 (COX2) activity and levels of both 6-keto-PGF1a, the stable metabolite of prostacyclin (PGI2) and 15-epi-lipoxin A4, a lipid mediator with a strong anti-inflammatory properties. Prostacyclin inhibits platelet aggregation and causes vasodilatation. Increased levels of 6-keto-PGF1a and 15-epi-lipoxin A4 may thus be the explanation for the anti-inflammatory and anti-atherosclerosis effects of PIO. Several clinical studies have shown that COX2 inhibition is associated with increased cardiovascular events. Thus, augmenting COX2 activity and the production of prostacyclin and 15-epi-lipoxin A4 may have potential favorable effects. The purpose of the study is to test whether PIO therapy is associated with an increase in serum and/or urine levels of 6-keto-PGF1a and 15-epi-lipoxin A4 in patients with diabetes mellitus type 2.

Timeline

Start

2010-02

Primary completion

2011-10

Completion

2011-12

Publications

• Background Ye Y, Lin Y, Perez-Polo JR, Uretsky BF, Ye Z, Tieu BC, Birnbaum Y. Phosphorylation of 5-lipoxygenase at ser523 by protein kinase A determines whether pioglitazone and atorvastatin induce proinflammatory leukotriene B4 or anti-inflammatory 15-epi-lipoxin a4 production. J Immunol. 2008 Sep 1;181(5):3515-23. doi: 10.4049/jimmunol.181.5.3515.
• Background Birnbaum Y, Ye Y, Lin Y, Freeberg SY, Huang MH, Perez-Polo JR, Uretsky BF. Aspirin augments 15-epi-lipoxin A4 production by lipopolysaccharide, but blocks the pioglitazone and atorvastatin induction of 15-epi-lipoxin A4 in the rat heart. Prostaglandins Other Lipid Mediat. 2007 Feb;83(1-2):89-98. doi: 10.1016/j.prostaglandins.2006.10.003. Epub 2006 Nov 7.
• Background Birnbaum Y, Ye Y, Lin Y, Freeberg SY, Nishi SP, Martinez JD, Huang MH, Uretsky BF, Perez-Polo JR. Augmentation of myocardial production of 15-epi-lipoxin-a4 by pioglitazone and atorvastatin in the rat. Circulation. 2006 Aug 29;114(9):929-35. doi: 10.1161/CIRCULATIONAHA.106.629907. Epub 2006 Aug 14.

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