In vivo MRI tracking of iron oxide nanoparticle-labeled human mesenchymal stem cells in limb ischemia.

BACKGROUND: Stem cell transplantation has been investigated for repairing damaged tissues in various injury models. Monitoring the safety and fate of transplanted cells using noninvasive methods is important to advance this technique into clinical applications. METHODS: In this study, lower-limb ischemia models were generated in nude mice by femoral artery ligation. As negative-contrast agents, positively charged magnetic iron oxide nanoparticles (aminopropyltriethoxysilane-coated Fe2O3) were investigated in terms of in vitro labeling efficiency, effects on human mesenchymal stromal cell (hMSC) proliferation, and in vivo magnetic resonance imaging (MRI) visualization. Ultimately, the mice were sacrificed for histological analysis three weeks after transplantation. RESULTS: With efficient labeling, aminopropyltriethoxysilane-modified magnetic iron oxide nanoparticles (APTS-MNPs) did not significantly affect hMSC proliferation. In vivo, APTS-MNP-labeled hMSCs could be monitored by clinical 3 Tesla MRI for at least three weeks. Histological examination detected numerous migrated Prussian blue-positive cells, which was consistent with the magnetic resonance images. Some migrated Prussian blue-positive cells were positive for mature endothelial cell markers of von Willebrand factor and anti-human proliferating cell nuclear antigen. In the test groups, Prussian blue-positive nanoparticles, which could not be found in other organs, were detected in the spleen. CONCLUSION: APTS-MNPs could efficiently label hMSCs, and clinical 3 Tesla MRI could monitor the labeled stem cells in vivo, which may provide a new approach for the in vivo monitoring of implanted cells.

Long-term MRI tracking of dual-labeled adipose-derived stem cells homing into mouse carotid artery injury.

BACKGROUND: Stem cell therapy has shown great promise for regenerative repair of injured or diseased tissues. Adipose-derived stem cells (ADSCs) have become increasingly attractive candidates for cellular therapy. Magnetic resonance imaging has been proven to be effective in tracking magnetic-labeled cells and evaluating their clinical relevance after cell transplantation. This study investigated the feasibility of imaging green fluorescent protein-expressing ADSCs (GFP-ADSCs) labeled with superparamagnetic iron oxide particles, and tracked them in vivo with noninvasive magnetic resonance imaging after cell transplantation in a model of mouse carotid artery injury. METHODS: GFP-ADSCs were isolated from the adipose tissues of GFP mice and labeled with superparamagnetic iron oxide particles. Intracellular stability, proliferation, and viability of the labeled cells were evaluated in vitro. Next, the cells were transplanted into a mouse carotid artery injury model. Clinical 3 T magnetic resonance imaging was performed immediately before and 1, 3, 7, 14, 21, and 30 days after cell transplantation. Prussian blue staining and histological analysis were performed 7 and 30 days after transplantation. RESULTS: GFP-ADSCs were found to be efficiently labeled with superparamagnetic iron oxide particles, with no effect on viability and proliferation. Homing of the labeled cells into the injured carotid artery tissue could be monitored by magnetic resonance imaging. CONCLUSION: Magnetically labeled ADSCs with expression of GFP can home into sites of vascular injury, and may provide new insights into understanding of cell-based therapy for cardiovascular lesions.

[Subintimal angioplasty for chronic arterial occlusive disease: a systematic review].

OBJECTIVE: To evaluate the clinical effectiveness of subintimal angioplasty in treating chronic arterial occlusive disease of lower extremity. METHODS: Eligible studies concerning treatment by subintimal angioplasty in patients with arterial occlusive disease of lower extremity were identified from electronic database, cross-reference search and relative articles. The study quality and data extraction of all relevant articles were assessed by three independent reviewers. The study endpoints were technical success, primary patency, limb salvage, and complications. RESULTS: A total of 352 studies were selected for comprehensive review. Fourteen studies including a total of 2350 patients matched the selection criteria. According to whether selective using of re-entry catheter were used or not, the technical success rates were 96.4% and 87% (P < 0.01). Limb salvage rate was 90.5% and 81.5% at 6 and 12 months respectively. Depending on whether preoperative use of anti-platelet drug, primary patency rate was 91% and 68.5% at 6 months respectively (P < 0.01). The complication rate was 8.25% without serious complications. CONCLUSION: This Meta-analysis suggests that subintimal angioplasty is a safe and effective method in treating chronic arterial occlusive disease of lower extremity with high technical success rate and limb salvage, and low serious complications. Selective using of re-entry devices and preoperative anti-platelet drug can improve the technical success rate and primary patency rate significantly. Despite the high rate of technical and clinical success of the procedure, randomized contrast trials and long-term follow-up results are required to confirm the efficacy of these results.

[Endovascular angioplasty for the treatment of long iliac artery chronic total occlusions].

OBJECTIVE: To evaluate the effectiveness, safety and feasibility of endovascular angioplasty in treating long iliac artery chronic total occlusions (CTO). METHODS: The clinical data from a consecutive series of patients with long (> 5 cm) iliac artery CTO who treated by endovascular angioplasty from January 2006 to December 2010 was retrospectively analyzed. There were 139 patients (157 limbs) with long iliac artery CTO treated by endovascular angioplasty in this study [male 93 and female 46, mean age (77 ± 10) years]. According to TASC II classification, there were 18 patients in type B, 89 patients in type C and 32 patients in type D. Recanalization of the occluded lesions was attempted with the left brachial and/or femoral access. RESULTS: The ankle brachial index increased from 0.42 ± 0.19 before treatment to 0.81 ± 0.26 after treatment. The rate of technical success was 96.2% (151/157) and the patency rate of iliac artery was 94.1% (111/118) during the follow-up. Significant restenosis or reocclusion was found in 7 iliac lesions and there were no major interventional complications, such as iliac artery rupture, stent displacement, pseudoaneurysms, and arteriovenous fistula. CONCLUSIONS: Endovascular angioplasty is an effective, safe and feasible method in treating long iliac CTO with high patency rate. Combined left brachial and femoral access can increase the technical success rate significantly.

[Effect of transarterial embolization on persistent type II endoleaks after endovascular aneurysm repair: a meta-analysis].

OBJECTIVE: To evaluate the clinical effectiveness of transarterial embolization in persistent type II endoleak after endovascular aneurysm repair (EVAR). METHODS: Eligible studies concerning treatment by transarterial embolization in patients with persistent type II endoleak after EVAR were identified from electronic database, cross-reference search and pertinent articles. All relevant studies were systematically reviewed and the data were extracted by two independent reviewers. The study endpoints were technical success, clinical success, mortality, and complications. RESULTS: A total of 56 studies were selected for comprehensive review. No randomized controlled trials were identified. Seven patient series, comprising 129 type II endoleaks, matched the selection criteria. The rate of technical success ranged from 69.7% to 100.0% (95% CI: 78.3% +/- 7.3%). During the follow-up, the clinical success rate was 100.0% in three studies using the criterion without increase of the aneurysm diameter by the end of followup; and in other 3 studies the disappearance rates of type II endoleak were 61.5%, 20.0%, and 78.9% respectively. No incidence of serious complications, rupture of aneurysmal sac, and intra-operational death were reported. CONCLUSION: Transarterial embolization is a main option in treating type II endoleak without serious complications. Despite the high rate of technical and clinical success of the procedure, long term follow-up and randomized contrast trials are needed to confirm the efficacy.