Treatment with telmisartan attenuates graft arteriosclerosis in murine cardiac allografts

Background

Chronic rejection remains the most prominent cause of graft failure after transplantation. Recently, it was reported that telmisartan can function as a partial agonist of peroxisome proliferator-activated receptor γ (PPARγ) in addition to a blocker of angiotensin II receptor. We investigated the effect of telmisartan on chronic rejection.

Methods

Hearts from Bm12 mice were transplanted into C57BL/6 mice (Class II mismatch), and allografts were harvested at 8 weeks after transplantation. Recipient mice were fed either control chow or chow containing telmisartan (10 mg/kg/day) from 1 day before transplantation. Proliferation assays of smooth muscle cells (SMCs), which were isolated from the aorta of B/6 mice, was performed.

Results

Although severe neo-intimal hyperplasia developed in allografts from control mice fed chow (luminal occlusion 70.9 ± 6.1%), neo-intimal hyperplasia was significantly attenuated in allografts from mice fed chow containing telmisartan (30.0 ± 10%, p < 0.001). Expression of interferon (IFN)-γ and interleukin (IL)-15 mRNAs and matrix metalloproteinase (MMP)-2 in allografts was significantly lower in telmisartan-treated mice than in control mice. Proliferation of smooth muscle cells (SMCs) in response to fetal bovine serum was suppressed significantly by telmisartan (10 μmol/liter). The PPARγ antagonist blocked telmisartan-induced suppression of SMC proliferation.

Conclusions

Telmisartan attenuates SMC proliferation via PPARγ activity and suppresses neo-intimal hyperplasia after transplantation. Telmisartan may be useful for suppressing chronic allograft rejection.

Keywords: transplantation, arteriosclerosis, smooth muscle cell, inflammation, pharmacology