Atorvastatin increases endothelial progenitor cells in balloon-injured mouse carotid artery

Dysregulation of autophagy activation induced by atorvastatin contributes to new-onset diabetes mellitus in western diet-fed mice

BACKGROUND AND AIMS

The incidence of statin-induced new-onset diabetes (NOD) is increasing but its underlying mechanisms remain unclear. We aimed to investigate the effects of various doses of atorvastatin (ATO)-induced autophagy on the development of NOD.

METHODS AND RESULTS

The isolated rat islets and MIN6 cells-treated with ATO, exhibited impaired glucose-stimulated insulin secretion, reduced insulin content, and induced apoptosis. Additionally, autophagy was induced at all doses (in vitro: 5, 10, 20 μM; in vivo: 10, 15, 20 mg/kg) in ATO-treated MIN6 cells or western diet (WD)-fed mice. In contrast to normal glucose-tolerant mice administered a low-dose (10 mg/kg) ATO, those treated with high-doses (15 or 20 mg/kg) exhibited impaired glucose tolerance. Furthermore, high-dose ATO-treated mice showed decreased β-cell mass and increased apoptosis compared to that of vehicle-treated mice. We also observed that the number of vesicophagous cells in the pancreas of 20 mg/kg ATO-treated WD-fed mice was higher than in vehicle-treated WD-fed mice. Inhibiting autophagy using 3-methyladenine (3-MA) and siAtg5 improved glucose tolerance in vivo and in vitro by preventing apoptotic β-cell death and restoring insulin granules.

CONCLUSION

These results indicate that high doses of ATO induced hyperactivated autophagy in pancreatic cells, leading to impaired insulin storage, decreased cell viability, and reduced functional cell mass, ultimately resulting in NOD development.

Dual effects of atorvastatin on angiogenesis pathways in the differentiation of mesenchymal stem cells

Atorvastatin (ATO) can improve the transplantation efficacy of mesenchymal stem cells (MSCs) after acute myocardial infarction. The present study aimed at ATO effects on the angiogenesis-signaling pathways from MSCs' differentiation to tissue angiogenesis. MSCs were first prepared from BALB/c mouse bone marrow. MTT assay was then done for the biodegradability of MSCs with the extracellular matrix. After that, the differentiation of cells into the bone and fat tissues was confirmed by Alizarin and Oil Red O staining. The extracellular matrix was then combined with the cells to the implant. Animals were intraperitoneally treated with ATO (2 and 40 mg/kg, daily) three days before cell transplantation to one week after. Finally, the assays were carried out by electron microscopy, immunocytochemistry, ELISA, Western blot, and RT-qPCR techniques. A phase-contrast microscope confirmed the morphology of cells. The cell differentiation into bone and fat tissues was confirmed by Alizarin red staining and flow cytometry, and the cell proliferation was confirmed by MTT assay. Unlike ATO 40 mg/kg group, ATO 2 mg/kg was significantly increased the CD31, eNOS, podocalyxin, von Willibrand factor, and alpha-smooth muscle actin proteins levels compared to the control group in vitro experiment. The expression of CD31 and VEGF proteins, as angiogenesis markers, and Ki-67 protein, as a proliferation marker, was significantly higher in a low dose of ATO (2 mg/kg) than that of the control group in vivo experiment. Unlike ATO 40 mg/kg, the expression levels of ERK, AKT, NF-ҝB, Rho, STAT3, Ets-1, HIF-1α, and VEGF proteins and genes were significantly increased in ATO 2 mg/kg compared to the control. A low dose of ATO can be a beneficial tool in the function of MSCs and their differentiation to tissue angiogenesis.

Relative Effect of Current Intensive Lipid-Lowering Drugs on Cardiovascular Outcomes in Secondary Prevention - A Meta-Analysis of 12 Randomized Trials

BACKGROUND

We aimed to investigate the comparative cardiovascular benefits of high-dose statin, ezetimibe-statin, and PCSK9 inhibitor-statin treatments in secondary prevention patients.Methods and Results:We selected 12 randomized controlled trials (n=131,978 patients) using PubMed and Embase (inception-June 1, 2018). Subgroup differences were explored by meta-regression and Cochran Q test. The relative effects of high-dose statin, ezetimibe-statin, and PCSK9 inhibitor-statin on major cardiovascular events (MACE), and revascularization were varied and decreased gradually, of which high-dose statin resulted in lower risk of MACE and revascularization than PCSK9 inhibitor-statin per 1 mmol/L reduction of low-density lipoprotein cholesterol (LDL-C): risk ratio (RR) for MACE, 0.86 (95% confidence interval (CI), 0.81-0.90) for high-dose statin, 0.90 (95% CI, 0.83-0.96) for ezetimibe-statin, and 0.94 (95% CI, 0.92-0.96) for PCSK9 inhibitor-statin; RR for revascularization, 0.84 (95% CI, 0.77-0.90) for high-dose statin, 0.91 (95% CI, 0.81-1.00) for ezetimibe-statin, and 0.94 (95% CI, 0.90-0.97) for PCSK9 inhibitor-statin. Similar relative effects of intensive lipid-lowering treatment were also observed in analyses of myocardial infarction and stroke, although no significant difference between groups was identified.

CONCLUSIONS

In secondary prevention patients, the relative benefits of high-dose statin, ezetimibe-statin, and PCSK9 inhibitor-statin treatments were varied and decreased gradually, of which high-dose statin was significantly superior to PCSK9 inhibitor-statin for improving MACE and revascularization per 1 mmol/L reduction of LDL-C.

Effects of various doses of atorvastatin on vascular endothelial cell apoptosis and autophagy in vitro

Atorvastatin (Lipitor™) is a lipid‑lowering agent that is widely used in the treatment of cardiovascular diseases. Previous research has largely focused on its cholesterol‑lowering effects; however, a limited number of studies have investigated the actions of atorvastatin on vascular endothelial cells. In the present study, the effects of various doses of atorvastatin were investigated on human umbilical vein endothelial cells (HUVECs). HUVECs were treated with various concentrations of atorvastatin in serum‑free or serum‑containing medium, and alterations in HUVEC morphology were observed. Cell survival and necrosis rates were evaluated using sulforhodamine B and lactate dehydrogenase assays, respectively. In addition, the protein expression levels of cellular apoptosis and autophagy markers were detected using western blot analysis. The results revealed that HUVEC morphology was altered following treatment with various concentrations of atorvastatin. In addition, autophagy was demonstrated to be induced by atorvastatin treatment at all concentrations, whereas high concentrations appeared to induce apoptosis and suppress the survival of HUVECs. In conclusion, the results of the present study suggested that various doses of atorvastatin may exert differential effects on HUVECs, and high doses may suppress angiogenesis. Therefore, atorvastatin may present a novel potential anti‑tumor therapeutic strategy. However, further studies are required to fully elucidate the association between the dose of atorvastatin and its clinical outcome.

Application of medical adhesive inhibits intimal hyperplasia involving the downregulation of ERK1/2 and eNOS levels

Vein graft remains the most broadly applied vascular material in coronary artery bypass surgery. However, the restenosis rate of the vein bridge following angioplasty is high. The present study investigated the effect of medical adhesive on vascular intimal hyperplasia, in addition to the signal transduction mechanism. A total of 36 New Zealand white rabbits were divided into three groups at random, including the normal group, the surgery group and the medical adhesive spray group. Following surgery for transplantation of the left external jugular vein to the ipsilateral common carotid artery for 4 weeks, the thickness and area of the intima and media of the vessel were measured on formalin‑fixed, paraffin wax‑embedded pathological sections using hematoxylin‑eosin staining, and alterations in the expression of proliferating cell nuclear antigen (PCNA), platelet endothelial cell adhesion molecule 1 (PECAM‑1), vascular cell adhesion protein 1 (VCAM‑1), extracellular signal‑regulated kinase (ERK)1/2, and endothelial nitric oxide synthase (eNOS) were detected by immunohistochemical staining, reverse transcription‑quantitative polymerase chain reaction analysis and western blotting. The levels of intimal hyperplasia in the medical adhesive spray group were markedly decreased compared with the surgery group. Consistently, PCNA, PECAM‑1 and VCAM‑1 were underexpressed in the medical adhesive spray group compared with the surgery group. ERK1/2 and eNOS were underexpressed in the medical adhesive spray group compared with the surgery group. Therefore, the application of medical adhesive may inhibit intimal hyperplasia, which may be associated with the restriction of the over‑distension of the vein graft by downregulating the ERK1/2 and eNOS levels, reducing injury to the vascular intima and inhibiting the signaling pathway involved in intimal hyperplasia.

Exosomes derived from endothelial progenitor cells attenuate vascular repair and accelerate reendothelialization by enhancing endothelial function

BACKGROUND AIMS

Exosomes, a key component of cell paracrine secretion, can exert protective effects in various disease models. However, application of exosomes in vascular repair and regeneration has rarely been reported. In this study, we tested whether endothelial progenitor cell (EPC)-derived exosomes possessed therapeutic effects in rat models of balloon-induced vascular injury by accelerating reendothelialization.

METHODS

Exosomes were obtained from the conditioned media of EPCs isolated from human umbilical cord blood. Induction of the endothelial injury was performed in the rats' carotid artery, and the pro-re-endothelialization capacity of EPC-derived exosomes was measured. The in vitro effects of exosomes on the proliferation and migration of endothelial cells were investigated.

RESULTS

We found that the EPC-derived exosomes accelerated the re-endothelialization in the early phase after endothelial damage in the rat carotid artery. We also demonstrated that these exosomes enhanced the proliferation and migration of endothelial cells in vitro. Moreover, endothelial cells stimulated with these exosomes showed increased expression of angiogenesis-related molecules.

CONCLUSIONS

Taken together, our results indicate that exosomes are an active component of the paracrine secretion of human EPCs and can promote vascular repair in rat models of balloon injury by up-regulating endothelial cells function.