Beneficial clinical effects of grape seed proanthocyanidin extract on the progression of carotid atherosclerotic plaques.

BACKGROUND: Atherosclerotic plaques indicate the occurrence of ischemia events and it is a difficult task for clinical physicians. Grape seed proanthocyanidin extract (GSPE) has been reported to exert an antiatherogenic effect by inducing regression of atherosclerotic plaques in animal experimental studies. In this study, the antiatherogenic effect of GSPE has been investigated in clinical use. METHODS: Consecutive 287 patients diagnosed with asymptomatic carotid plaques or abnormal plaque free carotid intima-media thickness (CIMT) were randomly assigned to the GSPE group (n = 146) or control group (n = 141). The patients in the GSPE group received GSPE 200 mg per day orally, while patients in the control group were only enrolled in a lifestyle intervention program. Carotid ultrasound examination was performed at baseline and 6, 12, 24 months during follow-up. Mean maximum CIMT (MMCIMT), plaque score, echogenicity of plaques and ischemic vascular events were recorded. RESULTS: As anticipated, after treatment, GSPE resulted in significant reduction in MMCIMT progression (4.2% decrease after six months, 4.9% decrease after 12 months and 5.8% decrease after 24 months) and plaque score (10.9% decrease after six months, 24.1% decrease after 12 months and 33.1% decrease after 24 months) for the primary outcome, while MMCIMT and plaque score were stable and even increased with the time going on in control group. The number of plaques and unstable plaques also decreased after treatment of GSPE. Furthermore, the carotid plaque can disappear after treatment with GSPE. The incidence rate for transitory ischemic attack (TIA), arterial revascularization procedure, and hospital readmission for unstable angina in GSPE group were statistically significant lower (P = 0.02, 0.08, 0.002, respectively) compared with the control group. CONCLUSIONS: GSPE inhibited the progression of MMCIMT and reduced carotid plaque size in GSPE treated patients, and with extended treatment, the superior efficacy on MMCIMT and carotid plaque occurred. Furthermore, the GSPE group showed lower rates of clinical vascular events.

Seeding endothelial progenitor cells on a self-expanding metal stent: an in vitro study.

PURPOSE: To demonstrate the feasibility of seeding a self-expanding metal stent with endothelial progenitor cells to enhance rapid reendothelialization, which is postulated to prevent local thrombus formation and restenosis after vascular intervention. MATERIALS AND METHODS: Endothelial progenitor cells and fibrinogen were isolated from the peripheral blood of a domestic swine and then cultured and identified. Ten self-expanding nitinol stents were incubated in the culture medium with a cell concentration of 1 x 10(6)/mL with (n = 5, study group) or without (n = 5, control group) fibrin gel (5 mg/mL fibrinogen and 0.10 NIHU/mL thrombin) for 24 hours. The cell coverage of the stents was documented with en face photography and scanning electron microscopy. After simulated use in vitro, the cells were removed from each stent, counted with a cytometer, sequentially cultured for three passages, and identified again to compare their properties with those of the original seeding line. RESULTS: After seeding the stent with the combination of endothelial progenitor cells and the fibrin gel coating, the stents took on a tube-like appearance with a confluent monolayer membrane. After digestion with trypsin, a mean of 2.5 x 10(5) +/- 1.3 cells were obtained from the fibrin gel stent (study group); fewer cells (4 x 10(4) +/- 1.5) were recovered from the bare stents (control group) (P < .01). The recovered cells, after amplification with culture, demonstrated the properties of the original endothelial progenitor cells. CONCLUSIONS: An endothelial progenitor cell-coated stent can be successfully fabricated by using fibrin gel as the bonding agent in vitro. Further in vivo research is warranted.

Transjugular intrahepatic portosystemic shunt with an autologous endothelial progenitor cell seeded stent: a porcine model.

RATIONALE AND OBJECTIVES: To evaluate the efficacy of a self-expanding metal stent seeded with autologous endothelial progenitor cells (EPCs) for preventing in-stent stenoses in transjugular intrahepatic portosystemic shunt (TIPS) in a swine model. MATERIALS AND METHODS: TIPS was performed in 18 young adult pigs, using a self-expanding nitinol stent (control, n = 8) and an autologous EPC-seeded stent (treatment, n = 10). All pigs were sacrificed at 2 weeks post-TIPS procedure. Portography was performed immediately before the euthanasia. Gross, microscopic, and immunohistochemistry of the TIPS tract specimens were examined. The proliferative response of the shunt was quantified histologically. RESULTS: TIPS was performed successfully in 16 swine, 2 animals died during the procedure. Another pig died of unknown causes 2 days post-procedure. At day 14 follow-up, portography and necropsy of the 15 remaining swine demonstrated that five shunts occluded and one shunt was stenotic (80%) in the control group (n = 6). Five shunts remained patent, two shunts were stenosed (50%, 70%), and the remaining two shunts were occluded in the treatment group (n = 9). The patency rate was significantly lower in the control group than in the treatment group, 0% versus 55.6% (P = .03). Histological analyses showed a significantly greater pseudointimal hyperplasia in the TIPS track of the control group than that of the treatment group (P < .05). Intact endothelium was documented in the lumina of all the EPC-implanted stent group. CONCLUSIONS: The EPC-seeded metal stent is feasibly fabricated in vitro and improves the patency in TIPS in a porcine model.

In vivo tracking of dual-labeled mesenchymal stem cells homing into the injured common carotid artery.

The aim of this study is to conduct in vivo, noninvasive magnetic resonance imaging of labeled rat bone mesenchymal stem cells (BMSCs) as they home into the site of injured common carotid artery following allograft transplantation. Our study was approved by the Institutional Committee on Animal Research. Purified rat BMSCs were dual labeled with superparamagnetic iron oxide (SPIO) particle and fluorescent DiI dye, and subsequently transplanted into recipient rats injured in the left common carotid arteries. Immediately before and 3 hr, 3, 7 and 12 days after transplantation, the labeled cells were monitored in vivo using a 7T micromagnetic resonance imaging (7T micro-MRI) scanner. The signal-to-noise ratios (SNRs) at the injured sites were corroborated with histological examination using Prussian blue staining and fluorescent imaging. Rat BMSCs were labeled with SPIO and DiI at 100% efficiency. When compared with the baseline level before transplantation, the SNR decreased significantly on Days 3 and 7 after injection in the experimental group (Dunnet t test, P < 0.05), whereas insignificant differences were observed after 3 hr and 12 days (Dunnet t test, P > 0.05). In the control group, no significant differences in SNR were found among different time points (ANOVA, P > 0.05). Histological analyses illustrated that red fluorescence and Prussian blue-positive cells were mainly distributed around the lesion areas of injured common carotid arteries. Rat BMSCs can be efficiently labeled with SPIO and DiI, and the directional homing of labeled cells to the site of injured common carotid arteries after intravascular transplantation could be tracked in vivo with 7T micro-MRI.

[In vitro MR imaging of Fe2O3-arginine labeled heNOS gene modified endothelial progenitor cells].

OBJECTIVE: To explore the feasibility of in vitro magnetic resonance imaging on Fe2O3-arginine labeled heNOS gene modified endothelial progenitor cells (EPCs). METHODS: Fe2O3 was incubated with arginine to form Fe2O3-arginine complex. Rabbit peripheral blood mononuclear cells (MNCs) were isolated and EPCs were isolated by adherence method, expanded and modified with heNOS gene using Lipofectamine 2000. After 48 hours, genetically modified EPCs were incubated with Fe2O3-arginine for 24 hours. Intracellular iron was detected by Prussian blue stain. The expression of heNOS gene was detected by Western blot. MTT assay was used to evaluate cell survival and proliferation of Fe2O3-arginine labeled heNOS-EPCs. Flow cytometry was used to measure cell apoptosis. The cells underwent in vitro MR imaging with various sequences. RESULTS: Iron-containing intracytoplasmatic vesicles could be clearly observed with Prussian blue staining, and the labeling rate of labeled heNOS-EPCs were similar to that of labeled EPCs (around 100%). Survival and apoptosis rates obtained by MTT and flow cytometry analysis were similar among labeled heNOS-EPCs, labeled EPCs and unlabeled EPCs with Fe2O3-arginine. The signal intensity on MRI was equally decreased in labeled heNOS-EPCs and labeled EPCs compared with that in unlabeled cells. The percentage change in signal intensity (DeltaSI) was most significant on T2*WI and DeltaSI was significantly lower in cells labeled for 7 days than that labeled for 1 days. CONCLUSIONS: The heNOS gene can be successfully transfected into rabbit peripheral blood EPCs using Lipofectamine2000. The heNOS-EPCs can be labeled with Fe2O3-arginine without significant change in viability and proliferation capacity. The labeled heNOS-EPCs can be imaged with standard 1.5 T MR equipment. The degree of MR signal intensity may indirectly reflect the cell count, growth and division status.

A rabbit model of atherosclerosis at carotid artery: MRI visualization and histopathological characterization.

To induce a rabbit model of atherosclerosis at carotid artery, to visualize the lesion evolution with magnetic resonance imaging (MRI), and to characterize the lesion types by histopathology. Atherosclerosis at the right common carotid artery (RCCA) was induced in 23 rabbits by high-lipid diet following balloon catheter injury to the endothelium. The rabbits were examined in vivo with a 1.5-T MRI and randomly divided into three groups of 6 weeks (n=6), 12 weeks (n=8) and 15 weeks (n=9) for postmortem histopathology. The lesions on both MRI and histology were categorized according to the American Heart Association (AHA) classifications of atherosclerosis. Type I and type II of atherosclerotic changes were detected at week 6, i.e., nearly normal signal intensity (SI) of the injured RCCA wall without stenosis on MRI, but with subendothelial inflammatory infiltration and proliferation of smooth muscle cells on histopathology. At week 12, 75.0% and 62.5% of type III changes were encountered on MRI and histopathology respectively with thicker injured RCCA wall of increased SI on T(1)-weighted and proton density (PD)-weighted MRI and microscopically a higher degree of plaque formation. At week 15, carotid atherosclerosis became more advanced, i.e., type IV and type V in 55.6% and 22.2% of the lesions with MRI and 55.6% and 33.3% of the lesions with histopathology, respectively. Statistical analysis revealed a significant agreement (p<0.05) between the MRI and histological findings for lesion classification (r=0.96). A rabbit model of carotid artery atherosclerosis has been successfully induced and noninvasively visualized. The atherosclerotic plaque formation evolved from type I to type V with time, which could be monitored with 1.5-T MRI and confirmed with histomorphology. This experimental setting can be applied in preclinical research on atherosclerosis.