Vascular endothelial growth factor-bound stents: application of in situ capture technology of circulating endothelial progenitor cells in porcine coronary model.

OBJECTIVES: We evaluated the in vivo performance of a newly devised vascular endothelial growth factor (VEGF)-bound stent in a porcine coronary model. BACKGROUND: An anti-CD34 antibody-bound stent, which captures endothelial progenitor cells (EPCs) to accelerate tissue formation, did not reduce intimal hyperplasia. By targeting the VEGF receptor, which is expressed on endothelial-lineage cells, we developed VEGF-bound stents that may enable selective capture of EPCs followed by rapid endothelialization. METHODS: Metallic stents were first coated with poly-(ethylene-co-vinyl alcohol), and then chemically bound with either VEGF or anti-CD34 antibody. These stents were placed in porcine coronary arteries for up to 14 days. Stent surface was evaluated by immunohistochemistry and by scanning electron microscope (SEM). RESULTS: After 2-day stenting with VEGF-bound stents, small populations of KDR (VEGF receptor-2)-positive cells adhered to the stent struts. After 7- and 14-day stenting, struts were fully covered with newly regenerated tissue. SEM images showed that the uniform tissue formed on struts was morphologically similar to native endothelium and was continuously connected with adjacent native endothelium. On the other hand, for the anti-CD34 antibody-bound stents, stent struts were rapidly covered by newly generated tissue that consisted of multicellular aggregates. CONCLUSIONS: Compared with anti-CD34 antibody-bound stents, VEGF-bound stents provide highly selective capture of EPCs, followed by rapid formation of intact endothelium tissue at an early period of stenting. These results suggest that VEGF-bound stents could represent a promising therapeutic option for cardiovascular stenting, although further long-term follow-up experiment with double-blinded fashion is needed prior to clinical application.

Impact of out-stent plaque volume on in-stent intimal hyperplasia: results from serial volumetric analysis with high-gain intravascular ultrasound.

BACKGROUND: Changes in out-stent plaque volume can be related to in-stent intimal hyperplasia. However, few data exist regarding the impact of out-stent plaque volume on in-stent intimal hyperplasia. METHODS: We prospectively performed volumetric intravascular ultrasound in 46 stable coronary patients (34 males, mean age of 66 years) immediately as well as 18 months after stenting. From the high-gain ultrasound images, out-stent plaque volume was calculated by extracting the stent volume from the external elastic membrane volume. Volumes of in-stent intimal hyperplasia and reference plaque were also evaluated. RESULTS: Out-stent plaque volume increased from 177.3 ± 100.8mm(3) to 190.7 ± 111.1mm(3) (p<0.05) in correlation with increases in-stent intimal hyperplasia (r=0.536, p<0.05). Under these conditions, changes in reference plaque volume correlated with those in LDL-C, which decreased from 121.2 ± 48.0mg/dl to 103.3 ± 48.9 mg/dl (r=0.43, p<0.05). Interestingly, increases in out-stent plaque volume in the silorimus-eluting stent (2.7 ± 1.2%) were lesser than those in the bare-metal stent (14.0 ± 11.0%, p<0.05). CONCLUSIONS: These results indicate that irrespective of LDL-C level, changes in out-stent plaque volume correlate with those in in-stent intimal hyperplasia. We suggest that silorimus-eluting stent can suppress in-stent intimal hyperplasia partially by affecting out-stent plaque, although further large-scale studies are required to define the role of out-stent plaque in the occurrence of in-stent intimal hyperplasia.

Gene and protein expression analysis of mesenchymal stem cells derived from rat adipose tissue and bone marrow.

BACKGROUND: Mesenchymal stem cells (MSC) are multipotent and reside in bone marrow (BM), adipose tissue and many other tissues. However, the molecular foundations underlying the differences in proliferation, differentiation potential and paracrine effects between adipose tissue-derived MSC (ASC) and BM-derived MSC (BM-MSC) are not well-known. Therefore, we investigated differences in the gene and secretory protein expressions of the 2 types of MSC. METHODS AND RESULTS: ASC and BM-MSC were obtained from subcutaneous adipose tissue and BM of adult Lewis rats. ASC proliferated as rapidly as BM-MSC, and had expanded 200-fold in approximately 2 weeks. On microarray analysis of 31,099 genes, 571 (1.8%) were more highly (>3-fold) expressed in ASC, and a number of these genes were associated with mitosis and immune response. On the other hand, 571 genes (1.8%) were more highly expressed in BM-MSC, and some of these genes were associated with organ development and morphogenesis. In secretory protein analysis, ASC secreted significantly larger amounts of growth factor and inflammatory cytokines, such as vascular endothelial growth factor, hepatocyte growth factor and interleukin 6, whereas BM-MSC secreted significantly larger amounts of stromal-derived factor-1α. CONCLUSIONS: There are significant differences between ASC and BM-MSC in the cytokine secretome, which may provide clues to the molecule mechanisms associated with tissue regeneration and alternative cell sources.

Pseudoaneurysmal formation in abdominal aorta associated with Escherichia coli infection.

Early and accurate diagnosis of infective aortic aneurysms (IAA) is critical for adequate treatment to optimize patient outcome. We report the case of an 84-year-old man who complained of severe back pain with high fever and was finally diagnosed as Escherichia coli-related IAA. Computed tomography showed a periaortic soft tissue density and irregular fringe adjacent to the non-dilated abdominal aorta suggesting the presence of pseudoaneurysm. In addition to intravenous antibiotic injection, an aneurysmectomy with extensive debridement and an in situ graft, were successfully performed. The case emphasizes the potential for rapid IAA change and the need for frequent radiologic follow-up.

Coronary arteriovenous fistulas complicated by complete atrioventricular block: A case report.

We report the case of a patient with bilateral coronary arteriovenous fistulas (CAVFs) connecting the right coronary artery and left circumflex coronary artery with the right atrium who had progression of first-degree atrioventricular (AV) block to complete AV block during a 4-year period. The His bundle electrogram revealed that the complete AV block was the result of a block at the level of the AV node. Dipyridamole stress thallium-201 myocardial imaging showed decreased perfusion in the inferoapical wall. Coronary angiography and computed tomography showed fistulas that arose from the AV nodal branch of the right coronary artery and from the distal portion of the circumflex coronary artery and drained into the right atrium. Because the fistulas were small, they were not repaired surgically, and a permanent pacemaker was implanted to treat the complete AV block. We presumed that the complication by complete AV block was due to abnormalities of the arteries feeding the AV node and chronic ischemia resulting from a coronary steal associated with the fistulas. To the best of our knowledge, this is the first report of CAVF complicated by complete AV block.

An enhanced device for transluminal retrieval of vascular stents without surgical procedures: experimental studies.

BACKGROUND: Although efforts have been focused on developing endovascular procedures by which intravascular devices such as stents could be effectively deployed, few data exist regarding devices for the nonsurgical retrieval of deployed stents. Therefore, we designed to enable retrieval of deployed stents without a surgical procedure. METHODS: The device consisted of four components: ultra-low profile forceps with 2.0 mm in diameter, conducting shaft with 1.8 mm in diameter, control handle by which the forceps is opened or closed, and a covering sheath. This device was designed to advance into the vessel lumen along a 0.014-inch guidewire by over the wire fashion. RESULTS: The forceps could firmly catch nonexpanded as well as expanded tubular-type stents with open cells in an in vitro model that was 4.0 mm in diameter. Then, we used this device in porcine renal arteries with 2.5-5.0 mm in diameter. At first, a fragmented 0.014-inch guidewire could be safely removed without vessel damage that was confirmed by intravascular ultrasound. This device could successfully remove four of five inappropriately and 11 of 14 appropriately deployed stents. Under these conditions, intravascular ultrasound demonstrated minor vessel wall dissection in two-third of cases. CONCLUSIONS: These results demonstrate that the present device can be used for transluminal removal of foreign bodies such as nonexpanded as well as expanded stents in acute phase. Further miniaturization may enable using this type of device in the renal as well as coronary arteries.

[Electrocardiographic diagnosis of acute coronary syndrome].

Acute myocardial infarction(AMI) and unstable angina(UA) are part of a spectrum of clinical disease collectively identified as acute coronary syndrome (ACS) which is the most common proximate cause of sudden cardiac death. In a diagnosis of ACS, electrocardiogram(ECG) is still important. But, it is somewhat difficult to find out abnormal findings of ECG when it is taken in early phase of ACS. Therefore, it is necessary to record ECG on several times and to follow up even if there is no ECG abnormalities at first recording. The effective interventions for patients with ACS, particularly ST-elevation MI(STEMI), are extremely time-sensitive. It is imperative that we evaluate efficient risk stratification, and effective treatment of patients with ACS as quickly as possible.

Coronary artery multistenting in the treatment of life-threatening refractory coronary spasm after coronary artery bypass grafting.

A 74-year-old man had undergone on-pump coronary artery bypass grafting (CABG) for effort-induced angina pectoris. Soon after CABG using the left internal thoracic artery for the left anterior descending artery and saphenous vein for the left circumflex artery, ST elevation was found in the inferior leads and complete atrioventricular block, ventricular tachycardia, and circulatory collapse occurred. Emergent coronary angiography revealed diffuse severe spasm of the right coronary artery (RCA). Despite the intravenous and intracoronary administration of massive doses of vasodilators and intra-aortic balloon pumping, the coronary spasm did not resolve. Five stents were deployed from the distal to the proximal portion of the RCA. After multistenting, coronary flow was dramatically improved and the ST elevations in the inferior leads were also improved. Coronary artery spasm after CABG is relatively rare, but when it occurs, it can be fatal. Multistenting is a useful treatment for life-threatening refractory coronary spasm after CABG.