Reversion-inducing-cysteine-rich protein with Kazal motif is involved in intimal hyperplasia in carotid arteries: a new insight in the prevention of restenosis after vascular angioplasty.

BACKGROUND

Overexpression of matrix metalloproteinase (MMP) has been implicated in the incidence of restenosis after vascular angioplasty. Reversion-inducing cysteine-rich protein with kazal motifs (RECK) is a membrane-anchored glycoprotein that negatively regulates the activity of MMPs, such as MMP-9 and MMP-2, which play a key role in the angiogenesis during tumor growth. This study was designed to investigate the potential association between RECK and restenosis after vascular angioplasty.

METHODS

Balloon-injured rabbit carotid arterial models were established. Arterial morphology was assessed by hematoxylin-eosin staining. The area of intimal hyperplasia was measured using image microscopy and image analyzer. The messenger RNA (mRNA) expression levels of RECK, MMP-9, and MMP-2 were detected using reverse transcription-polymerase chain reaction (RT-PCR) at 7, 14, and 21 days. Vascular smooth muscle cells (VSMCs) were transfected with RECK small interfering RNA (siRNA). VSMC proliferation rate was detected by MTT assay at 24, 48 and 72 hr. The protein expression of RECK, MMP-9, and MMP-2 was determined by Western blot.

RESULTS

MMP-2 and MMP-9 in carotid artery of rats were significantly overexpressed in the injured-artery group, compared with unmanipulated control and contralateral uninjured groups (P < 0.05). With the time of the injury extended, MMP-2 and MMP-9 mRNA levels gradually increased. RECK showed a marked peak of mRNA level at 7 days after injury, compared with unmanipulated control and contralateral uninjured groups (P < 0.001). However, the increasing trend gradually decreased at 14 days after the balloon surgery. RECK mRNA was still detectable at 21 days postoperatively, but the expression level of RECK mRNA in injured and contralateral uninjured groups was significantly lower than that in unmanipulated control group (P < 0.001). The expression level of RECK protein in VSMCs in transfected group was significantly lower compared with that in untransfected group, whereas the expression of MMP-2 and MMP-9 proteins in transfected group was significantly higher compared with that in untransfected group. Over the extension of transfection time, the proliferation of VSMCs in transfected group was increased gradually, compared with negative and blank plasmid controls (P < 0.05).

CONCLUSIONS

RECK, as siRNA-mediated RECK silencing regulation of MMP-9 and MMP-2, plays an important role in intimal hyperplasia, which provides a new target for prevention and treatment of restenosis after vascular angioplasty.