Inhibitory effects of mesenchymal stem cells in intimal hyperplasia after balloon angioplasty

Improved therapeutic effects on vascular intimal hyperplasia by mesenchymal stem cells expressing MIR155HG that function as a ceRNA for microRNA-205

Coronary artery bypass grafting (CABG) is an effective treatment for coronary heart disease, with vascular transplantation as the key procedure. Intimal hyperplasia (IH) gradually leads to vascular stenosis, seriously affecting the curative effect of CABG. Mesenchymal stem cells (MSCs) were used to alleviate IH, but the effect was not satisfactory. This work aimed to investigate whether lncRNA MIR155HG could improve the efficacy of MSCs in the treatment of IH and to elucidate the role of the competing endogenous RNA (ceRNA). The effect of MIR155HG on MSCs function was investigated, while the proteins involved were assessed. IH was detected by HE and Van Gieson staining. miRNAs as the target of lncRNA were selected by bioinformatics analysis. qRT-PCR and dual-luciferase reporter assay were performed to verify the binding sites of lncRNA-miRNA. The apoptosis, Elisa and tube formation assay revealed the effect of ceRNA on the endothelial protection of MIR155HG-MSCs. We observed that MIR155HG improved the effect of MSCs on IH by promoting viability and migration. MIR155HG worked as a sponge for miR-205. MIR155HG/miR-205 significantly improved the function of MSCs, avoiding apoptosis and inducing angiogenesis. The improved therapeutic effects of MSCs on IH might be due to the ceRNA role of MIR155HG/miR-205.

Impact of adipose-derived stem cells on aortic tensile strength in a model of abdominal aortic aneurysm

Introduction

Abdominal Aortic Aneurysm (AAA) is a highly morbid condition and is the 11th leading cause of death in the United States. Treatment options are limited to operative interventions, with minimal non-operative options. Prior literature has demonstrated a benefit to the use of mesenchymal stem cells (MSCs) in attenuating AAA formation. We demonstrate the utility of MSCs in treating AAA in swine, focusing on the mechanical and structural characteristics of aortic tissue after treatment.

Methods

16 Yorkshire pigs underwent retroperitoneal exposure of the infrarenal aorta, with subsequent induction of AAA with peri-adventitial elastase and collagenase. A 1 × 4 cm piece of Gelfoam, an absorbable gelatin-based hemostatic agent, was soaked in media or human MSCs and placed directly on the vessel for control and experimental animals. At postoperative day 21, animals were sacrificed and the infrarenal aorta at this location was harvested for analysis. Tensile strength was measured using a tensiometer, from which Young's modulus and maximum strain were calculated.

Results

All animals survived the surgery and post-operative course. Young's elastic modulus for the aneurysm control group was 15.83 ± 1.61 compared to 22.13 ± 2.34 for the stem cell treated segment, p = 0.0316. There was no significant difference in the peak stress between groups.

Conclusions

This is the first study to demonstrate the mechanical effects of stem cell therapy on a model of AAA in swine. Young's modulus, which characterizes the intrinsic capacity of a tissue to withstand stress, was greater in the animals treated with MSCs compared to control animals with aneurysms. This methodology can be utilized in future large animal models to develop cell and drug-based therapies for AAA.

Recent advance in treatment of atherosclerosis: Key targets and plaque-positioned delivery strategies

Atherosclerosis, a chronic inflammatory disease of vascular wall, is a progressive pathophysiological process with lipids oxidation/depositing initiation and innate/adaptive immune responses. The coordination of multi systems covering oxidative stress, dysfunctional endothelium, diseased lipid uptake, cell apoptosis, thrombotic and pro-inflammatory responding as well as switched SMCs contributes to plaque growth. In this circumstance, inevitably, targeting these processes is considered to be effective for treating atherosclerosis. Arriving, retention and working of payload candidates mediated by targets in lesion direct ultimate therapeutic outcomes. Accumulating a series of scientific studies and clinical practice in the past decades, lesion homing delivery strategies including stent/balloon/nanoparticle-based transportation worked as the potent promotor to ensure a therapeutic effect. The objective of this review is to achieve a very brief summary about the effective therapeutic methods cooperating specifical targets and positioning-delivery strategies in atherosclerosis for better outcomes.

Human umbilical cord mesenchymal stem cell-derived exosomal microRNA-148a-3p inhibits neointimal hyperplasia by targeting Serpine1

BACKGROUND

Restenosis is inevitable when patients undergo percutaneous transluminal angioplasty due to neointimal hyperplasia (NIH). Human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-Exos) have been studied in the field of cardiovascular diseases. However, the effects and mechanisms of hucMSC-Exos on NIH are unclear. We aimed to investigate whether MSC-Exos regulate vascular smooth muscle cell (VSMC) functions to inhibit NIH and explore the underlying mechanisms.

METHODS

HucMSCs and mouse VSMCs were isolated and characterized by flow cytometry and immunofluorescence. HucMSC-Exos were identified by transmission electron microscopy, nanoparticle tracking analysis and western blots. Exosomes (Exos) were intravenously injected into mice with left common carotid artery ligation, and their effects on NIH were assessed by haematoxylin and eosin (H&E) and immunohistochemistry staining. The effects of hucMSC-Exos on VSMCs were evaluated by Cell Counting Kit-8, scratch wound, Transwell and Western blot assays. MicroRNA sequencing data in the Gene Expression Omnibus and mRNA sequencing results were used to identify potential molecules in hucMSC-Exos and target genes in VSMCs, respectively. We tested the regulatory effect of microRNAs in Exos and target genes in VSMCs using overexpression and knockdown experiments.

RESULTS

Primary hucMSCs, VSMCs and hucMSC-Exos were isolated and characterized. Administration of hucMSC-Exos suppressed NIH after artery ligation. H&E and immunohistochemistry results showed that hucMSC-Exos decreased the intima and media area and intima/media ratio, increased the contractile phenotype protein SM22a in the media layer and downregulated Serpine1 expression in the carotid artery. Exos were ingested by VSMCs, which inhibited migration and upregulated SM22a expression by suppressing Serpine1 expression in vitro. MiR-148a-3p was enriched in hucMSC-Exos and repressed Serpine1 by targeting its 3' untranslated region. Moreover, exosomal miR-148a-3p suppressed VSMC phenotypic switching and migration by targeting Serpine1.

CONCLUSIONS

We found that hucMSC-Exos inhibited NIH in a mouse carotid artery ligation model and that the inhibitory effects on VSMC phenotypic switching and migration were mediated by delivery of miR-148a-3p to VSMCs to target Serpine1.

Association of the DNA Methyltransferase and Folate Cycle Enzymes’ Gene Polymorphisms with Coronary Restenosis

Background: In recent years, the interest in genetic predisposition studies for coronary artery disease and restenosis has increased. Studies show that polymorphisms of genes encoding folate cycle and homocysteine metabolism enzymes significantly contribute to atherogenesis and endothelial dysfunction. The purpose of this study was to examine some SNPs of genes coding for folate cycle enzymes and DNA methyltransferases as risk factors for in-stent restenosis. Methods: The study included 113 patients after stent implantation and 62 patients without signs of coronary artery disease at coronary angiography as the control group. Real-time PCR and RFLP-PCR were applied to genotype all participants for MTHFR rs1801133, MTHFR rs1801131, MTR rs1805087, MTRR rs1801394, DNMT1 rs8101626, DNMT3B rs1569686, and DNMT3B rs2424913 gene polymorphisms. Statistical data processing was carried out using the R language and the SPSS Statistics 20 software. Results: Statistically significant differences in the DNMT3B gene polymorphisms were found between patients with and without in-stent restenosis. An association of TT rs1569686 and TT rs2424913 genotypes with the development of restenosis was revealed. The TT rs1569686 genotype was more frequent in the patients under the age of 65 years and in the subgroup of patients with post-12-month restenosis, as was the minor GG genotype for MTR rs1805087. The homozygous TT genotype for MTHFR rs1801133 was significantly more frequent in the subgroup over 65 years old. The frequencies of the heterozygous genotype for the MTRR gene and the minor GG homozygotes for the DNMT1 gene were significantly higher in the subgroup with in-stent restenosis under 65 years old. Conclusions: The results of this study could be used for a comprehensive risk assessment of ISR development, determining the optimal tactics and an individual approach in the treatment of patients with coronary artery disease before or after percutaneous coronary interventions, including homocysteine-lowering treatment in patients with hyperhomocysteinemia and a high risk of in-stent restenosis.

Therapeutic Effect of Adipose Derived Mesenchymal Stem Cell Transplantation in Reducing Restenosis in a Murine Angioplasty Model

BACKGROUND

Percutaneous transluminal angioplasty (PTA) is the first line of treatment for stenosis in the arteriovenous fistula (AVF) created to provide access for hemodialysis, but resenosis still occurs. Transplants of adipose-derived mesenchymal stem cells (AMSCs) labeled with green fluorescent protein (GFP) to the adventitia could reduce pro-inflammatory gene expression, possibly restoring patency in a murine model of PTA for venous stenosis.

METHODS

Partial nephrectomy of male C57BL/6J mice induced CKD. Placement of the AVF was 28 days later and, 14 days after that, PTA of the stenotic outflow vein was performed with delivery of either vehicle control or AMSCs (5×10⁵) to the adventitia of the vein. Mice were euthanized 3 days later and gene expression for interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha TNF-α) analyzed, and histopathologic analysis performed on day 14 and 28. GFP (+) AMSCs were tracked after transplantation for up to 28 days and Doppler ultrasound performed weekly after AVF creation.

RESULTS

Gene and protein expression of IL-1β and TNF-α, fibrosis, proliferation, apoptosis and smooth muscle actin decreased, and the proportions of macrophage types (M2/M1) shifted in a manner consistent with less inflammation in AMSC-transplanted vessels compared to controls. After PTA, AMSC-treated vessels had significantly higher wall shear stress, average peak, and mean velocity, with increased lumen vessel area and decreased neointima/media area ratio compared to the control group. At 28 days after delivery, GFP (+) AMSC were present in the adventitia of the outflow vein.

CONCLUSIONS

AMSC-treated vessels had improved vascular remodeling with decreased proinflammatory gene expression, inflammation, and fibrotic staining compared to untreated vessels.

Ultrasound monitoring of magnet-guided delivery of mesenchymal stem cells labeled with magnetic lipid–polymer hybrid nanobubbles

Mesenchymal stem cells labeled with positively charged magnetic lipid–polymer hybrid nanobubbles could be tracked for magnet-guided delivery onto the site of an injured artery using ultrasound.

Prolonged versus brief balloon inflation during arterial angioplasty for de novo atherosclerotic disease: a systematic review and meta-analysis

OBJECTIVE

Angioplasty is a fundamental treatment for atherosclerotic disease and may be performed as the sole therapy in small vessel disease. However, the ideal duration of balloon inflation has not yet been identified. Our study investigated whether prolonged inflation of at least 1-min duration, when compared with brief inflation, affects residual stenosis after arterial angioplasty.

DATA SOURCES AND METHODS

Two independent reviewers conducted a systematic review of EMBASE, MEDLINE, CENTRAL, trial registries and grey literature, using pre-specified search syntax. Data abstraction and quantitative analysis was performed independently, according to pre-specified criteria. The primary outcome was residual stenosis after initial angioplasty, in addition to other pre-specific clinical and radiographic outcomes. All analyses were stratified by coronary, cerebrovascular, and peripheral territory. The study protocol is published and registered on PROSPERO (CRD42018092702).

RESULTS

Six relevant articles were identified, of which one investigated peripheral vascular angioplasty and five investigated coronary artery angioplasty, encompassing 1496 procedures. The studies were at moderate risk of bias. Minimal heterogeneity within coronary studies allowed for subgroup meta-analysis. Prolonged inflation was significantly associated with lower risk of residual stenosis post-inflation in the pooled coronary trials (RR 1.76 [95% CI 1.46-2.12], I² = 0%, p < 0.001) in addition to approaching significance in the peripheral vascular trial (RR 2.40 [95% CI 0.94-6.13], p = 0.07). Prolonged inflation was associated with less risk of arterial dissection and need for adjunctive procedures such as stenting. Following adjunctive procedures, less residual stenosis was still observed in the prolonged angioplasty group in the reported coronary studies. Follow-up data did not reveal a significant difference in the presence of restenosis, however there was a long-term benefit of prolonged inflation in reducing overall severity of stenosis.

DISCUSSION

This is the first review investigating outcomes related to duration of balloon inflation. Both coronary and peripheral vascular evidence are in agreement that prolonged angioplasty balloon inflation greater than 60 s appears to be associated with improved immediate post-inflation results. However, long-term data is heterogeneous and inconsistently reported. We propose further investigation to address outstanding long-term outcomes, particularly in small vessel territories such as tibial vessels where angioplasty is often used as the only endovascular therapy.

TRIAL REGISTRATION

This protocol has been registered with the International Prospective Register of Systematic Reviews (PROSPERO: CRD42018092702 ) prior to conduct of the review.

Prolonged versus brief balloon inflation during arterial angioplasty for de novo atherosclerotic disease: protocol for a systematic review

BACKGROUND

Angioplasty is a fundamental treatment for atherosclerotic disease in the cardiac, cerebrovascular, and peripheral vascular beds. However, the optimal duration of balloon inflation has not been identified. Our study will investigate whether prolonged angioplasty balloon inflation of at least 1 min duration, when compared with brief inflation, affects residual stenosis after arterial angioplasty.

METHODS

In compliance with PRISMA, two independent reviewers will conduct a systematic review of EMBASE, MEDLINE, CENTRAL, trial registries, grey literature, and ancestry and citation search. Data abstraction, quantitative, and quantitative meta-analysis will be performed according to pre-specified criteria. The primary outcome is residual stenosis immediately after initial angioplasty; however, secondary outcomes will include multiple short and long term pre-specific clinical and radiographic outcomes. Risk of bias, subgroup analyses, and sensitivity analyses are planned.

DISCUSSION

Despite the ubiquitous use of angioplasty in atherosclerotic disease and multiple trials investigating the ideal balloon inflation duration, there are no systematic reviews evaluating prolonged angioplasty balloon inflation. Currently synthesized evidence is insufficient to confidently direct clinical decision-making, and the current variation in operator preference of balloon angioplasty duration suggests ongoing clinical equipoise. Given the known availability of current primary evidence, our study intends to synthesize the evidence and guide future clinical decision making and investigation.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018092702.

Exosomes from mesenchymal stem cells expressing miR-125b inhibit neointimal hyperplasia via myosin IE

Intercellular communication between mesenchymal stem cells (MSCs) and their target cells in the perivascular environment is modulated by exosomes derived from MSCs. However, the potential role of exosome-mediated microRNA transfer in neointimal hyperplasia remains to be investigated. To evaluate the effects of MSC-derived exosomes (MSC-Exo) on neointimal hyperplasia, their effects upon vascular smooth muscle cell (VSMC) growth in vitro and neointimal hyperplasia in vivo were assessed in a model of balloon-induced vascular injury. Our results showed that MSC-Exo were internalised by VSMCs and inhibited proliferation and migration in vitro. Further analysis revealed that miR-125b was enriched in MSC-Exo, and repressed the expression of myosin 1E (Myo1e) by targeting its 3' untranslated region. Additionally, MSC-Exo and exosomally transferred miR-125b repressed Myo1e expression and suppressed VSMC proliferation and migration and neointimal hyperplasia in vivo. In summary, our findings revealed that MSC-Exo can transfer miR-125b to VSMCs and inhibit VSMC proliferation and migration in vitro and neointimal hyperplasia in vivo by repressing Myo1e, indicating that miR-125b may be a therapeutic target in the treatment of vascular diseases.

Mesenchymal Stem Cell Sheets Exert Antistenotic Effects in a Rat Arterial Injury Model

Restenosis after catheter or surgical intervention substantially affects the prognosis of arterial occlusive disease. Mesenchymal stem cells (MSCs) may have antistenotic effects on injured arteries. MSC transplantation from the adventitial side of an artery is safer than endovascular transplantation but has not been extensively examined. In this study, a rat model of femoral artery injury was used to compare the antistenotic effects of transplanted cell sheets and transplanted cell suspensions. Rat adipose-derived stem cells (ASCs) were used as the source of MSCs. For both cell sheets and suspensions, 6 × 10⁶ MSCs were transplanted on the day of arterial injury. MSC sheets attenuated neointimal hyperplasia more than MSC suspensions (intima-to-media ratio in hematoxylin/eosin-stained sections: 0.55 ± 0.13 vs. 1.14 ± 0.12; p < 0.05). Cell engraftment (assessed by immunohistochemistry or bioluminescence imaging of luciferase-expressing cells), arterial re-endothelialization (evaluated by immunohistochemical staining for rat endothelial cell antigen-1), and restriction of vascular smooth muscle cell proliferation in the neointima (double-staining of alpha-smooth muscle actin and phospho-histone H3) were greater when MSC sheets were applied than when MSC suspensions were used. In conclusion, MSC sheets exhibited better antistenotic and cell engraftment properties than MSC suspensions. MSC sheet transplantation from the adventitial side is a promising therapy for prevention of arterial restenosis.

Effects of amniotic epithelial cell transplantation in endothelial injury

Purpose

Human amniotic epithelial cells (hAECs) are promising tools for endothelial repair in vascular regenerative medicine. We hypothesized that these epithelial cells are capable of repairing the damaged endothelial layer following balloon injury of the carotid artery in adult male rats.

Results

Two days after injury, the transplanted hAECs were observed at the luminal side of the arterial wall. Then, 4 weeks after the injury, significant intimal thickening was observed in both untreated and cell implanted vessels. Constriction was decreased in both implanted and control animals. Immunohistochemical analysis showed a few surviving cells in the intact arterial wall, but no cells were observed at the site of injury. Interestingly, acetylcholine-induced dilation was preserved in the intact side and the sham-transplanted injured arteries, but it was a trend toward decreased vasodilation in the hAECs’ transplanted vessels.

Conclusion

We conclude that hAECs were able to incorporate into the arterial wall without immunosuppression, but failed to improve vascular function, highlighting that morphological implantation does not necessarily result in functional benefits and underscoring the need to understand other mechanisms of endothelial regeneration.

Limiting reductive stress for treating in-stent stenosis: the heart of the matter?

Restenosis after balloon angioplasty and stenting (BAS) remains an unsolved clinical dilemma for patients with coronary artery disease. A better understanding of the mechanisms that drive this phenomenon is likely to lead to more effective treatments. In this issue of the JCI, Ali et al. uncover a critical redox axis with the antioxidant enzyme glutathione peroxidase-1 (GPX1) at its hub and identify potential new therapeutic targets, such as ROS1 tyrosine kinase. This study represents a potential new approach to finding a treatment for BAS, with implications that may extend beyond BAS to other vasculopathies involving vascular remodeling.