Henghui Yin

In vitro differences between smooth muscle cells derived from varicose veins and normal veins

OBJECTIVE The theory of primary venous dilatation leading to secondary valvular incompetence and varicose vein formation has received more attention nowadays. Although many studies have investigated the role of the main components of the venous wall in the development of varicose veins, the leading cause remains unknown. The present study was designed to establish the role of smooth muscle cells (SMCs) of the tunica media on the pathogenesis of varicose veins by analyzing the phenotypic and functional differences between SMCs derived from varicose veins and normal veins. METHODS SMCs were isolated and cultured from saphenous veins of patients with varicose veins and normal veins. Cell proliferation and migration rates were compared. Expression of phenotype-dependent markers and matrix metalloproteinase-2 (MMP) production were analyzed by immunoblotting. Total collagen synthesis was evaluated by measuring the radioactivity of L-[3, 4-(3)H]proline in the media and the cell layer. RESULTS SMCs derived from varicose veins demonstrated increased proliferation (2-fold, P < .01), migration (3-fold, P < .001), MMP-2 production (3-fold, P < .01), and collagen synthesis (>2-fold, P < .001), with decreased expression of phenotype-dependent markers compared with SMCs derived from normal veins (P < .05). CONCLUSION SMCs derived from varicose veins are more dedifferentiated and demonstrate increased proliferative and synthetic capacity than SMCs derived from normal veins. These properties may contribute to the remodeling of the venous wall and the weakening of its antipressure capacity.

MicroRNA-1298 is regulated by DNA methylation and affects vascular smooth muscle cell function by targeting connexin 43

AIMS Growing evidence links microRNA to the process of peripheral vascular disease. Recently, we have found that microRNA-1298(miR-1298) is one of the most significantly down-regulated microRNAs in human arteries with arteriosclerosis obliterans (ASO) of the lower extremities. However, little is known regarding its role in the process of ASO. The present study aimed to investigate the expression, regulatory mechanisms, and functions of miR-1298 in the process of ASO. METHODS AND RESULTS Using quantitative reverse-transcription PCR and in situ hybridization assays, miR-1298 was observed predominantly expressed in the vascular smooth muscle cells (VSMCs) and was significantly down-regulated in ASO compared with normal arteries. Pyrosequencing analysis revealed that the miR-1298 DNA upstream of CpG sites were hypermethylated in ASO compared with normal arteries. Next, the luciferase reporter assay revealed that miR-1298 down-regulation is related with upstream DNA CpG site hypermethylation. Introducing a miR-1298 mimic into cultured VSMCs significantly attenuated cell proliferation and migration. Connexin 43 (Cx43) was validated to be a functional target of miR-1298 that was involved in the miR-1298-mediated cellular effects. Finally, lentivirus-mediated delivery of miR-1298 and its target Cx43 into a rat carotid balloon injury model indicated that re-overexpression of miR-1298 significantly decreased neointimal formation by targeting connexin 43. CONCLUSION Our data demonstrate a specific role of the upstream DNA methylation/miR-1298/Cx43 pathway in regulating VSMC function and suggest that modulation of miR-1298 levels may offer a novel therapeutic approach for ASO.

A novel dendritic nanocarrier of polyamidoamine-polyethylene glycol-cyclic RGD for “smart” small interfering RNA delivery and in vitro antitumor effects by human ether-à-go-go-related gene silencing in anaplastic thyroid carcinoma cells

The application of RNA interference techniques is promising in gene therapeutic approaches, especially for cancers. To improve safety and efficiency of small interfering RNA (siRNA) delivery, a triblock dendritic nanocarrier, polyamidoamine-polyethylene glycol-cyclic RGD (PAMAM-PEG-cRGD), was developed and studied as an siRNA vector targeting the human ether-à-go-go-related gene (hERG) in human anaplastic thyroid carcinoma cells. Structure characterization, particle size, zeta potential, and gel retardation assay confirmed that complete triblock components were successfully synthesized with effective binding capacity of siRNA in this triblock nanocarrier. Cytotoxicity data indicated that conjugation of PEG significantly alleviated cytotoxicity when compared with unmodified PAMAM. PAMAM-PEG-cRGD exerted potent siRNA cellular internalization in which transfection efficiency measured by flow cytometry was up to 68% when the charge ratio (N/P ratio) was 3.5. Ligand-receptor affinity together with electrostatic interaction should be involved in the nano-siRNA endocytosis mechanism and we then proved that attachment of cRGD enhanced cellular uptake via RGD-integrin recognition. Gene silencing was evaluated by reverse transcription polymerase chain reaction and PAMAM-PEG-cRGD-siRNA complex downregulated the expression of hERG to 26.3% of the control value. Furthermore, gene knockdown of hERG elicited growth suppression as well as activated apoptosis by means of abolishing vascular endothelial growth factor secretion and triggering caspase-3 cascade in anaplastic thyroid carcinoma cells. Our study demonstrates that this novel triblock polymer, PAMAM-PEG-cRGD, exhibits negligible cytotoxicity, effective transfection, “smart” cancer targeting, and therefore is a promising siRNA nanocarrier.

Abdominal aorta aneurysms in children: single-center experience of six patients.

BACKGROUND Abdominal aortic aneurysms (AAA) are rare in children and are associated with significant morbidity and mortality as in adults. We summarize our experience in the diagnosis and management of AAAs in 6 children at a single institution. METHODS The clinical data of 6 pediatric patients with AAAs treated at our hospital from November 2005 to November 2008 were retrospectively analyzed. RESULTS There were 4 males and 2 females with a mean age at diagnosis of 8 years (range, 17 months to 18 years). All patients presented with pulsatile abdominal masses. Color Doppler ultrasonography and computed tomography angiography were the primary diagnostic tools. One patient has a history of tuberous sclerosis, and 1 had Takayasus arteritis; no risk factors or identifiable causes were found in the other patients. All of the AAAs identified were infrarenal. Surgical reconstruction with aneurysm resection and prosthetic graft placement was performed successfully in all 6 cases. No intraoperative or postoperative complications occurred. Mean follow-up has been 48 months (range, 32 to 69). In 1 patient, recurrence was noted at 3 years postoperatively. The patients family declined further surgery, and the patient died, likely of rupture of the aneurysm at 41 months postoperatively. All other patients are currently alive and well. CONCLUSIONS Our experience indicates that good outcomes can be obtained in children with AAAs with prompt and accurate diagnosis and surgical management with artificial grafts.

Desmuslin gene knockdown causes altered expression of phenotype markers and differentiation of saphenous vein smooth muscle cells

OBJECTIVE Phenotypic alterations of vascular smooth muscle cells (VSMCs) appear critical to the development of primary varicose veins. Previous study indicated desmuslin, an intermediate filament protein, was differentially expressed in smooth muscle cells (SMCs) isolated from varicose veins; thus, it was naturally hypothesized that altered desmuslin expression might in turn affect the functioning of VSMCs, leading to the phenotypic alterations and varicose vein development. METHODS In this study, expression of desmuslin in normal human saphenous vein SMCs was knocked down using small interfering RNA (siRNA), and control cells were treated with a scrambled siRNA sequence. The levels of several phenotypic markers including smooth muscle (SM) alpha-actin and smooth muscle myosin heavy chain (SM-MHC) were assessed. Collagen formation, matrix metalloproteinase expression (MMP-2), and cytoskeletal and morphological changes were also examined. RESULTS SMCs treated with desmuslin siRNA exhibited significantly increased levels of collagen synthesis and MMP-2 expression and decreased expression levels of SM alpha-actin, SM-MHC, and smoothelin and exhibited disassembly of actin stress fibers when compared with the control cells. Changes in cell morphology and actin fiber networks in VSMCs treated with desmuslin siRNA were consistent with a lower degree of differentiation. CONCLUSIONS These results indicated desmuslin expression is required for the maintenance of VSMC phenotype. Decreased desmuslin expression may affect differentiation of VSMCs and ultimately contribute to the development of varicose veins.

Management of Acute Mesenteric Ischemia A Critical Review and Treatment Algorithm

Background: Acute mesenteric ischemia (AMI) due to a sudden loss or decrease in blood perfusion to the mesentery represents a highly lethal condition. However, the optimal surgical management remains debatable and merits a more clear recommendation based on a higher level of evidence. Methods: A systematic review of articles published between 2000 and 2013 was performed. Patients were divided into endovascular treatment (ET), open surgery (OS), and hybrid technique (HT) groups. Data of patients’ demographics, procedural information, clinical outcomes including mortality, morbidity, primary patency rate, technique success, primary intestinal resection rate, and second-look laparotomy rate, and follow-up were all retrieved. Comparison between the ET and the OS groups was made using 2-sided Student t test and 2-sided χ2 test or Fisher exact test where appropriate. Results: Twenty-eight articles with a total of 1110 patients were included for the review. The ET group had lower in-hospital mortality and morbidity but similar survival rate during follow-up compared to the OS group. The primary patency rate was higher in the ET group. The overall bowel resection rate was lower in the ET group, and nearly every patient in the cohort who required second-look laparotomy required bowel resection. The HT group seemed to have the lowest mortality and acceptable second-look laparotomy rate and morbidity. Comparison between the HT group and other groups was not possible due to the limited number of cases available for review. Conclusion: Endovascular treatment may serve as a first-line therapy for select patients when there is a low suspicion for intestinal necrosis. Open surgery should be reserved for emergency conditions requiring exploratory laparotomy. Hybrid technique may be an especially effective approach for treating AMI, with low morbidity and mortality, although further studies are required comparing it to OS and ET.

The value of endografts in the surgical management of arterial lesions secondary to Behçet disease

Background: This study summarizes our experience in the surgical management of arterial lesions secondary to Behçet disease (BD) and assesses the value of endografts. Methods: Data from BD patients with arterial lesions managed surgically in our center from January 1998 to December 2015 were studied retrospectively. Surgical procedures, graft selection, graft‐related complications, and retreatments were analyzed. Results: We recruited 33 patients (29 men and 4 women; male‐to‐female ratio, 7.25:1) with an average age of 36.7 years (range, 25‐51 years). The arterial lesions included 27 aneurysms in 24 patients and nine stenotic or occlusive lesions in nine patients. Immunosuppressive therapy was administered routinely preoperatively and postoperatively as recommended. Altogether, 15 great saphenous veins (GSVs), 8 synthetic grafts, and 13 endografts were used in 36 primary procedures. The mean follow‐up duration was 3.8 ± 2.9 years. Graft‐related pseudoaneurysm was seen in three GSVs (20%) and in three synthetic grafts (38%) at the anastomosis, but not in endograft implantations (log‐rank, P = .171). Graft occlusions were observed in 1 GSV (7%), 2 synthetic (25%), and 2 endografts (15%; log‐rank, P = .881). Graft infection occurred in one synthetic graft (13%) and in one endograft (8%) but not in the GSVs (log‐rank, P = .689). Graft‐related artery rupture occurred in only one endograft (8%). Two patients died, giving a mortality rate of 6.1%. Conclusions: In the surgical management of arterial lesions secondary to BD, endografts were superior to GSV and synthetic grafts in decreasing anastomotic pseudoaneurysm. However, improvements are needed to enhance the long‐term patency and reduce infections.

Chimney Technique in Supra-Aortic Branch Reconstruction in China: A Systematic and Critical Review of Chinese Published Experience

Background: The chimney graft (CG) technique has been proposed as a complete endovascular supra-aortic branch reconstruction for aortic pathologies. Due to the rapid growth of thoracic endovascular aortic repair (TEVAR) in China, we aimed to investigate the current data of the CG technique in this most populous country. Methods: Studies of supra-aortic branch reconstruction using the CG technique from Chinese centers were collected and analyzed. Results: A total of 294 patients from Chinese centers who underwent TEVAR with CGs were included. There were 301 CGs performed, with a technical successful rate of 97.7%. The rate of early type I endoleaks was 7.1%, and the patency rate of the CGs was desirable. Balloon-expandable bare CGs were significantly associated with good early outcomes and a low rate of endoleaks. Conclusion: Current data from China revealed positive outcomes using CGs for supra-aortic branch reconstruction. Balloon-expandable bare CGs may be the first choice according to the data available but should be considered with caution.

Surface Coating of Polytetrafluoroethylene with Extracellular Matrix and Anti-CD34 Antibodies Facilitates Endothelialization and Inhibits Platelet Adhesion Under Sheer Stress

Expanded polytetrafluoroethylene (ePTFE) polymers do not support endothelialization because of nonconductive characteristics towards cellular attachment. Inner surface modification of the grafts can improve endothelialization and increase the long-term patency rate of the ePTFE vascular grafts. Here we reported a method of inner-surface modification of ePTFE vascular graft with extracellular matrix (ECM) and CD34 monoclonal antibodies (CD34 mAb) to stimulate the adhesion and proliferation of circulating endothelial progenitor cells on ePTFE graft to enhance graft endothelialization. The inner surface of ECM-coated ePTFE grafts were linked with CD34 mAb in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide (EDC/NHS) solution and the physicochemical properties, surface morphology, biocompatibility, and hemocompatibility of the grafts were studied. The hydrophilicity of CD34 mAb-coated graft inner surface was significantly improved. Fourier transform infrared spectroscopy analysis confirmed ECM and CD34 mAb cross-linking in the ePTFE vascular grafts with our method. Scanning electron microscopy analysis showed protein layer covering uniformly on the inner surface of the modified grafts. The cell-counting kit-8 (CCK-8) assay confirmed that the modified graft has no obvious cytotoxicity. The modified graft showed a low hemolytic rate (0.9%) in the direct contact hemolysis test, suggesting the modification improved hemocompatibility of biopolymers. The modification also decreased adhesion of platelets, while significantly increased the adhesion of endothelial cells on the grafts. We conclude that our method enables ePTFE polymers modification with ECM and CD34 mAb, facilitates endothelialization, and inhibits platelet adhesion on the grafts, thus may increase the long-term patency rate of the prosthetic bypass grafts.

Endovascular versus Open Surgery Repair of Ruptured Abdominal Aortic Aneurysms in Hemodynamically Unstable Patients: Literature Review and Meta-Analysis

BACKGROUND The better outcome achieved by endovascular aortic repair (EVAR) in ruptured abdominal aortic aneurysm (rAAA) patients might derive from the fact that patients with hemodynamic instability preferentially underwent open repair. To further evaluate the effect of EVAR for rAAAs, a meta-analysis of studies in which hemodynamic instability was similar between the 2 treatment groups was conducted. METHODS MEDLINE, EMBASE, ISI Web of Knowledge, and the Cochrane Library were searched from January 2004 to May 2014 for randomized controlled trials (RCTs) and observational studies that compared EVAR with open surgery repair in rAAA patients. RESULTS Three RCTs and 10 observational studies covering 1,784 patients were included. Perioperative mortality occurred in 27.3% of the patients treated with EVAR and in 38.1% of the patients who underwent open repair. Subgroup analysis revealed consistent results in favor of EVAR in single-center, observational studies. Subgroup analysis and meta-regression analysis indicated that the superior effect of EVAR might be associated with more anatomically suitable patients in EVAR group. CONCLUSION The findings from our meta-analysis support EVAR in properly selective rAAA patients.