Differentiation profile of peripheral blood-derived vascular progenitor cell predicts intimal hyperplasia after coronary stenting

5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside reduces intimal hyperplasia of tissue engineering blood vessel by inhibiting phenotype switch of vascular smooth muscle cell

Intimal hyperplasia (IH) is the cause of clinical failure in patients with vascular transplants and intravascular stents. The proliferation and phenotype switching of vascular smooth muscle cells (VSMCs) play important roles in IH. Inhibiting the proliferation of VSMCs and maintaining the differentiated phenotype of VSMCs is one way to reduce IH. In this article, 5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR) was used in experiments after drug screening. We found that the metabolism, autophagy, and differentiation of VSMCs were enhanced which were important to the normal function of VSMCs, but the secretion of VSMCs was reduced after AICAR treatment. AICAR induces G1 phase arrest and inhibits the proliferation of VSMCs using the MTT and EdU assays and cell cycle analysis. Then, the rat carotid artery vessel transplantation model was used to evaluate the function of AICAR in vivo. AICAR-modified tissue-engineered blood vessels (TEBVs) had a higher patency rate and less IH than the control TEBVs. In conclusion, AICAR can improve the normal function of VSMCs by increasing the metabolism and autophagy of VSMCs but inhibit the proliferation, paracrine, and phenotypes switching of VSMCs, further contribute the reducing of IH in TEBVs. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 744-752, 2017.

Natural history of low-intensity neointimal tissue after an everolimus-eluting stent implantation: a serial observation with optical coherence tomography

Although previous optical coherence tomography (OCT) studies reported that restenosis tissue after implantation of a drug-eluting stent (DES) was composed of a variety of cells, the clinical significance of morphologic characteristics for in-stent neointimal tissue as assessed by OCT has not been clarified. We experienced a patient with stable angina who underwent percutaneous coronary intervention with a 2.5 × 18-mm DES implantation 6 months before the OCT examination. OCT imaging showed a mild intimal hyperplasia (39 % neointimal hyperplasia) with eccentric, heterogeneous tissue, predominantly of low signal intensity. Seventeen months after the initial procedure, OCT revealed a significant increase in percent neointimal hyperplasia of 58 %, with morphologically different intimal tissue of concentric homogeneous high intensity in the stented segments. This finding suggests that low-intensity intimal tissue morphology detected by OCT could be a morphometric predictor of late neointimal tissue growth after DES implantation.

Porphyromonas gingivalis promotes neointimal formation after arterial injury through toll-like receptor 2 signaling

We previously demonstrated that Porphyromonas gingivalis infection induces neointimal hyperplasia with an increase in monocyte chemoattractant protein (MCP)-1 after arterial injury in wild-type mice. Toll-like receptor (TLR) 2 is a key receptor for the virulence factors of P. gingivalis. The aim of this study was to assess whether TLR2 plays a role in periodontopathic bacteria-induced neointimal formation after an arterial injury. Wild-type and TLR2-deficient mice were used in this study. The femoral arteries were injured, and P. gingivalis or vehicle was injected subcutaneously once per week. Fourteen days after arterial injury, the murine femoral arteries were obtained for histopathologic and immunohistochemical analyses. The immunoglobulin-G levels of the P. gingivalis-infected groups were significantly increased in comparison with the level in the corresponding noninfected groups in both wild-type and TLR2-deficient mice. TLR2 deficiency negated the P. gingivalis-induced neointimal formation in comparison with the wild-type mice, and reduced the number of positive monocyte chemoattractant protein-1 cells in the neointimal area. These findings demonstrate that P. gingivalis infection can promote neointimal formation after an arterial injury through TLR2 signaling.

Increased circulating CD3+/CD31+ T cells in patients with acute coronary syndrome

The number of circulating endothelial progenitor cells (EPCs) is considered to be a surrogate marker for coronary artery disease (CAD). Recent studies have identified a novel T-cell subset labeled with CD3(+)/CD31(+), which is necessary for EPC colony formation and constitutes the central cluster. However, the clinical relevance of the CD3(+)/CD31(+) T cells in CAD remains unclear. We sought to clarify whether circulating CD3(+)/CD31(+) T cells are increased in patients with acute coronary syndrome (ACS). Circulating CD3(+)/CD31(+) T cells were determined in 16 ACS patients undergoing emergency percutaneous coronary intervention (PCI) and in 16 control subjects with angiographically normal coronary arteries. Although no differences between the groups were found in baseline patient characteristics, the ratio of circulating CD3(+)/CD31(+) T cells before PCI was higher in ACS patients as compared with that in control subjects (51.8 % ± 7.8 % vs 31.8 % ± 9.6 %, respectively; P < 0.001). The increased ratio of CD3(+)/CD31(+) T cells in ACS patients was not altered 24 h after PCI, but became comparable with that in control subjects within 6 months after PCI. These results suggest that mobilization of CD3(+)/CD31(+) T cells occurs in ACS, but is no longer detectable at 6 months after PCI.

Mobilization of CD34+ KDR+ endothelial progenitor cells predicts target lesion revascularization

BACKGROUND

Endothelial lesion and regeneration are critical events in the process leading to in-stent restenosis (ISR) after bare metal stent (BMS) percutaneous coronary intervention (PCI).

OBJECTIVES

To prospectively investigate the relationship between biomarkers reflecting endothelial turnover and the occurrence of ISR.

METHODS

We performed a multicenter prospective observational study that included 156 patients undergoing elective PCI with BMS. Endothelial lesion was assessed by the enumeration of circulating endothelial cells (CECs). Endothelial regeneration was evaluated by enumeration of circulating CD34+ progenitor cells (CD34+ PCs) and CD34+ KDR+ endothelial progenitor cells (EPCs). Measurements were performed before PCI, and 6 and 24 h after PCI. Dynamic changes were evaluated by calculating the delta value of each marker. The primary and secondary endpoints of the study were clinical target lesion revascularizations (TLRs) and major adverse cardiovascular events (MACEs) after 6 months of follow-up.

RESULTS

During follow-up, 28 MACEs were recorded, including 27 TLRs. PCI induced a significant rise in the numbers of CECs, CD34+ PCs, and CD34+ KDR+ EPCs. Baseline, 6-h and 24-h levels of these markers did not differ between patients with and without TLR. The delta percentage of CD34+ KDR+ EPCs was significantly reduced in patients with TLR as compared with patients without TLR (- 0.56 ± 8.1 vs. 2.91 ± 6.2; P = 0.015). In multivariate analysis, the delta percentage of CD34+ KDR+ EPCs independently predicted the occurrence of TLR and MACEs (P = 0.02 and P = 0.014, respectively).

CONCLUSION

The endothelial regenerative response to injury induced by PCI, assessed by CD34+ KDR+ EPCs mobilized among progenitor cells, determines the risk of TLR and MACEs in stable coronary artery disease patients.

Neo-intimal hyperplasia, diabetes and endovascular injury

Diabetes is a significant major risk factor for peripheral arterial disease (PAD) and critical limb ischaemia (CLI), the latter which is also the most common cause of amputation in these patients. Revascularisation of the lower extremities of such patients is imperative for limb salvage and has become First-line therapy. However, the incidence of restenosis following endovascular stenting is very high and is largely due to neo-intimal hyperplasia (NIH), the regulation of which is for the greater part not understood. This article therefore reviews our understanding on the regulation of NIH following stent-induced vascular injury, and highlights the importance of future studies to investigate whether the profile of vascular progenitor cell differentiation, neo-intimal growth factors and lumen diameters predict the severity of post-stent NIH in the peripheral arteries. Results from future studies will (1) better our understanding of the regulation of NIH in general, (2) determine whether combinations of any of the vascular factors discussed are predictive of the extent of NIH postoperatively, and (3) potentially facilitate future therapeutic targets and/or change preventive strategies.

Association of midregional proadrenomedullin with coronary artery stenoses, soft atherosclerotic plaques and coronary artery calcium

Midregional proadrenomedullin (MR-proADM) is elevated in patients with heart failure and myocardial infarction. The aim of this study was to evaluate the association of MR-proADM with the grade of coronary artery stenosis, presence of coronary artery soft plaques and coronary artery calcification score (CACS), determined by 64-multislice computed tomography (MSCT) in patients without known prior cardiovascular disease. This retrospective study included 107 patients undergoing MSCT for confirmation (or exclusion) of coronary artery disease. MR-proADM levels were measured in all patients. The assessment of coronary artery stenoses, CACS and soft coronary plaques was made by MSCT using known criteria. The MR-proADM [median (25th-75th percentiles)] level was 0.33 (0.21-0.43) nmol/l. The MR-proADM level was 0.28 (0.22-0.40) nmol/l in patients with coronary stenoses ≥50% (n = 23) versus 0.33 (0.27-0.40) nmol/l in patients with coronary stenoses <50% (n = 83, P = 0.59), 0.33 (0.26-0.40) nmol/l in patients with soft plaques (n = 56) versus 0.33 (0.25-0.41) nmol/l in patients without soft plaques (n = 50, P = 0.73) and 0.33 (0.25-0.39) nmol/l in patients with CACS <200 (n = 81) versus 0.32 (0.26-0.44) nmol/l in patients with CACS ≥200 (n = 26, P = 0.77). In multivariate analysis, the MR-proADM level was a significant correlate of coronary artery stenoses [odds ratio (OR) = 0.93; 95% confidence interval (CI) 0.86-0.99; P = 0.026] and soft plaques (OR = 0.94; 95% CI 0.90-0.99; P = 0.015) but not of CACS (OR = 0.98; 95% CI 0.93-1.03; P = 0.36). A decreased MR-proADM level is an independent correlate of the presence of coronary artery disease and of soft atherosclerotic plaques. Patients with decreased MR-proADM levels may need invasive examinations to diagnose more severe forms of coronary artery disease.