Rapamycin Combined with α-Cyanoacrylate Contributes to Inhibiting Intimal Hyperplasia in Rat Models

The effect of lncRNA MIR155HG-modified MSCs and exosome delivery to synergistically attenuate vein graft intimal hyperplasia

Background

The mesenchymal stem cells (MSCs) were used to repair tissue injury. However, the treatment effect was not satisfactory. We investigated whether lncRNA MIR155HG could promote survival and migration of MSCs under oxidative stress, which mimics in vivo environments. Furthermore, we studied the protective effect of exosomes secreted by MSCs transfected with MIR155HG on endothelial cells. This study aimed to determine whether exploiting MSCs and exosomes modified with lncRNA MIR155HG would exert synergistic therapeutic effect to attenuate vein graft intimal hyperplasia more effectively.

Methods

Lentivirus containing lncRNA MIR155HG overexpressing vector was packaged and used to infect MSCs. Then, CCK-8 assay, flow cytometry, Transwell assay, and Elisa assay were used to assess the functional changes of MSCs with overexpressed MIR155HG (OE-MSCs). Furthermore, the associated pathways were screened by Western blot. MIR155HG-MSCs-derived exosomes (OE-exo) were collected and co-cultured with human umbilicus vein endothelial cell (HUVEC). We validated the protective effect of OE-exo on HUVEC. In vivo, both MSCs and exosomes modified with MIR155HG were injected into a vein graft rat model via tail vein. We observed MSCs homing and intimal hyperplasia of vein graft using a fluorescent microscope and histological stain.

Results

Our study found that lncRNA MIR155HG promoted proliferation, migration, and anti-apoptosis of MSCs. NF-κB pathway took part in the regulation process induced by MIR155HG. OE-exo could enhance the activity and healing ability of HUVEC and reduce apoptosis. In vivo, OE-MSCs had a higher rate of homing to vascular endothelium. The combined treatment with OE-MSCs and OE-exo protected vascular endothelial integrity, reduced inflammatory cell proliferation, and significantly attenuated intimal hyperplasia of vein graft.

Conclusion

LncRNA MIR155HG could promote the survival and activity of MSCs, and reduce the apoptosis of HUVECs using exosome delivery. Exploiting MSCs and exosomes modified with MIR155HG could attenuate vein graft intimal hyperplasia more effectively and maximize the surgical effect.

A novel Nanocellulose-Gelatin-AS-IV external stent resists EndMT by activating autophagy to prevent restenosis of grafts

Vein grafts are widely used for coronary artery bypass grafting and hemodialysis access, but restenosis remains the "Achilles' heel" of these treatments. An extravascular stent is one wrapped around the vein graft and provides mechanical strength; it can buffer high arterial pressure and secondary vascular dilation of the vein to prevent restenosis. In this study, we developed a novel Nanocellulose-gelatin hydrogel, loaded with the drug Astragaloside IV (AS-IV) as an extravascular scaffold to investigate its ability to reduce restenosis. We found that the excellent physical and chemical properties of the drug AS-IV loaded Nanocellulose-gelatin hydrogel external stent limit graft vein expansion and make the stent biocompatible. We also found it can prevent restenosis by resisting endothelial-to-mesenchymal transition (EndMT) in vitro. It does so by activating autophagy, and AS-IV can enhance this effect both in vivo and in vitro. This study has added to existing research on the mechanism of extravascular stents in preventing restenosis of grafted veins. Furthermore, we have developed a novel extravascular stent for the prevention and treatment of restenosis. This will help optimize the clinical treatment plan of external stents and improve the prognosis in patients with vein grafts.

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The NC-Gelatin extravascular stent has suitable physicochemical properties to prevent restenosis of the grafted veins.

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The NC-Gelatin extravascular stent has excellent biocompatibility, which is critical for grafting veins.

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The NC-Gelatin extravascular stent prevents restenosis by activating autophagy against EndMT.

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AS-IV can enhance the effect of the stent to activate autophagy against EndMT.

Bletilla striata Polysaccharide Prevents Restenosis of Vein Graft Through Inhibiting Cell Proliferation in Rat Model

Coronary artery bypass grafting (CABG) is still the most effective method for the treatment of coronary heart disease at present. However, the restenosis of vein grafts following surgery is an important complication of CABG. In this study, Bletilla striata polysaccharide (BSP), which has anti-inflammatory and antiproliferative properties, was used to prevent or delay the proliferation of venous bridge endothelial cells in a rat model. We transplanted the autogenous jugular vein to the rat carotid artery, and wrapped it with BSP. We carried out experiments in 4 groups (with 24 rats in each group): a high-BSP dose group (the HBG group, 10 mg), a low-BSP dose group (the LBG group, 3 mg), a pluronic gel group (the gel group), and a control group. Vein grafts were then harvested after 3, 14, and 28 days. Following transplantation, we used color Doppler ultrasound to assess the patency of the transplanted vein. The grafted veins were stained with hematoxylin and eosin (H&E) and Masson to measure the thickness of the intima and media of the blood vessels. Proliferating cell nuclear antigen (PCNA) and vascular cell adhesion molecule-l (VCAM-1) were assessed in vein grafts by immunohistochemistry and western blotting. We detected a significant reduction in the proliferation of endothelial cells in the BSP group compared with the control group (P < 0.05). H&E and Masson's trichrome staining showed that the extent of intimal hyperplasia in transplanted veins from the high BSP group (HBS) (67.42 ± 0.54 µm) and low BSP group (LBS) (120.83 ± 1.87 µm) groups was significantly lower than that in the control group (257.03 ± 2.74 µm, P < 0.05), and that the extent of intimal hyperplasia in the HBS group was lower than that in the LBS group (P < 0.05). We found that the effect of BSP was dose-dependent, as high-dose BSP had a more significant inhibitory effect on cell proliferation than low-dose BSP (P < 0.05). The results of immunohistochemistry and western blotting showed that PCNA and VCAM-1 were significantly downregulated in the BSP treatment group on days 14 and 28 (P < 0.05). BSP inhibits the proliferation of vascular endothelial cells and reduces the expression of VCAM-1, thereby inhibiting the restenosis of graft veins.

Chaiqi decoction ameliorates vascular endothelial injury in metabolic syndrome by upregulating autophagy

OBJECTIVE

The present study aimed to investigate the protective effect of the Chaiqi decoction on vascular endothelial injury in metabolic syndrome and to determine whether the underlying mechanism was associated with autophagy.

METHODS

Chaiqi formula granules were administered to a rat model of metabolic syndrome established by feeding with a high-salt-sugar-fat diet (HSSFD). The drug-containing serum was used in a hyperglycemia cell model established using HUVECs cultured with palmitic acid PA. The influence of the Chaiqi decoction on metabolic syndrome-related vascular endothelial injury and autophagy was investigated. Autophagy flux was assessed in vitro by transfecting cells with GFP-mRFP-LC3 adenoviruses or incubating with DALGreen and DAPRed.

RESULTS

The metabolic syndrome model rats displayed adiposity, hyperglycemia, dyslipidemia, hypertension, thickened intima, deposition of various forms of collagen and lipid droplets, downregulated levels of phosphorylated endothelial nitric oxide synthase and nitric oxide, upregulated expression of endothelin 1, and dysfunctional autophagy. All these abnormalities were ameliorated by administration of the Chaiqi decoction to the metabolic syndrome rats. Furthermore, the Chaiqi-containing serum could upregulate autophagy similarly to rapamycin, in a time-dependent manner.

CONCLUSION

The Chaiqi decoction could ameliorate vascular endothelial injury by improving autophagy in metabolic syndrome.