Retinoic acids may inhibit vascular smooth muscle cell proliferation, but may promote endothelial cell proliferation in cell culture. However, little data are available about the effects of all-trans-retinoic acid (ATRA) on endothelial regeneration and functional recovery in an experimental model of vascular injury. Accordingly, we investigated whether ATRA may attenuate neointima formation and accelerate endothelial regeneration with functional recovery in balloon-injured rat aorta. Twelve-week-old male Sprague-Dawley rats underwent endothelial denudation of the thoracic aorta by balloon injury. Fourteen rats were fed a standard rat pellet diet. Another 14 rats were fed ATRA (1.5 mg/day) for 2 weeks. The animals were killed on day 14 for organ chamber study and morphometric analysis. Rats in the ATRA group had a significantly improved acetylcholine-induced relaxation response than those in control group. However, endothelial independent response was not significantly different between the two groups. The extent of reendothelialization was markedly superior in the ATRA group compared with control group (p>0.05). Furthermore, neointima area and the ratio of neointima to medial area were significantly less in ATRA group than in control group (p>0.05). In conclusion, ATRA may accelerate endothelial regeneration with functional recovery, and attenuate neointima formation in balloon-injured rat aorta.
Acetylcholine/pharmacology ; Animal ; Aorta, Thoracic/physiology ; Aorta, Thoracic/injuries ; Aorta, Thoracic/drug effects* ; Balloon Dilatation/adverse effects ; Endothelium, Vascular/physiology ; Endothelium, Vascular/drug effects ; Male ; Muscle Relaxation/physiology ; Muscle Relaxation/drug effects ; Muscle, Smooth, Vascular/physiology ; Muscle, Smooth, Vascular/drug effects ; Rats ; Rats, Sprague-Dawley ; Regeneration/physiology ; Regeneration/drug effects ; Tretinoin/pharmacology* ; Tunica Intima/physiology ; Tunica Intima/pathology* ; Tunica Intima/drug effects* ; Vasodilator Agents/pharmacology

AIMOsteopontin 13-peptide(Gly158-Lys170), containing multi-function domains was used to inhibit the VSMC adhesion, migration. The mechanism of 13-peptide inhibiting neointima formation was investigated.

METHODSThe effect of 13-peptide on VSMC adhesion was tested by adhesion assay. The restenosis model was prepared balloon injury after administration of 13-peptide for 1 h, and then the 13-peptide was given by an intravenous drip for 7 days. The expression changes of OPN, FAK, ILK in vessel wall were detected by immunohistochemistry and Western blot.

RESULTSThe 13-peptide dose-dependently reduced adhesion of VSMC in OPN matrix, and the infiltration of macrophage in vessel wall also was reduced in the treatment group after balloon injury. The expression of OPN, FAK, ILK was down-regulated following with the inhibition of neointima thickening.

CONCLUSIONThe OPN 13-peptide can inhibit inflammation and neointima formation by blocking the binding of OPN to it's receptors.

Animals ; Cell Adhesion ; drug effects ; Cells, Cultured ; Disease Models, Animal ; Male ; Muscle, Smooth, Vascular ; cytology ; drug effects ; metabolism ; Osteopontin ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Tunica Intima ; pathology

BACKGROUNDThe dysfunction of vascular endothelial cells plays a key role in starting and facilitating restenosis. The acceleration of intima repair and the recovery of endothelial function would reduce the restenosis rate. This study was undertaken to assess the effect of granulocyte-macrophage colony stimulating factor (GM-CSF) on the repair of damaged iliac arteries.

METHODSTwenty-four male New Zealand white rabbits undergoing primary iliac artery deendothelization were randomly divided into two groups (GM-CSF group and control group). The GM-CSF group received a subcutaneous injection of GM-CSF [10 microg x kg(-1) x d(-1)], and the control group was given a subcutaneous injection of equivalent saline. The iliac arteries of all animals were damaged by balloon after 7 days. The levels of nitric oxide (NO) were detected before, 1 week, 2 weeks and 4 weeks after angioplasty. The repair and hyperplasia of the intima were observed microscopically and the indices of stenosis were evaluated by computerized planimetry after 4 weeks of angioplasty.

RESULTSThe NO levels of the GM-CSF group were higher than those of the control group 2 weeks and 4 weeks after angioplasty [(91.92 +/- 11.57) micromol/L vs. (81.67 +/- 12.18) micromol/L; (97.67 +/- 10.13) micromol/L vs. (83.16 +/- 12.64) micromol/L]. Four weeks after balloon damage, histological examination showed that neointima formation, vascular smooth muscle cells and fibrous tissue of the GM-CSF group were less than those of the control group. The endothelium of the GM-CSF group was more integrated, and stenosis of lumen was slighter than that of the control group. Morphometry showed the lumen area of the GM-CSF group was larger than that of the control group [(1.27 +/- 0.31) mm(2) vs. (0.92 +/- 0.24) mm(2)], the neointimal area and percent of intima hyperplasia were significantly smaller than those of the control group [(0.85 +/- 0.34) mm(2) vs. (1.18 +/- 0.38) mm(2); (40 +/- 7)% vs. (55 +/- 6)%].

CONCLUSIONGM-CSF could facilitate the repair of the intima, reduce neointima formation, better the function of the endothelium, and decrease the rate of restenosis.

Angioplasty, Balloon ; adverse effects ; Animals ; Endothelium, Vascular ; pathology ; Granulocyte-Macrophage Colony-Stimulating Factor ; pharmacology ; Hyperplasia ; Iliac Artery ; Male ; Nitric Oxide ; blood ; Rabbits ; Tunica Intima ; drug effects ; pathology

OBJECTIVETo study the relationship between inflammation and neointimal proliferation after coronary stent implantation in porcine model.

METHODSTwenty normal minipigs were randomly divided into group A (implanted with 316L bare metal stents), group B (implanted with 605L bare metal stents), group C (implanted with PLGA coating 605L stents), and group D (implanted with rapamycin-loaded PLGA coating 605L stents). Each minipig was implanted with two same stents in left anterior descending artery and right coronary artery. Four weeks later, the animals were sacrificed and histomorphometric measurements on the stent-segment coronary arteries were made to calculate the correlation between inflammation area and neointimal area.

RESULTSGroup D had the smallest neointimal area [(0.64 +/- 0.38) mm2, P < 0. 001] and inflammation area (median 0.00 mm2, P = 0.009) among all the groups, while there were no statistical differences among group A, B, and C in neointimal area [(2.09 +/- 0.90), (2.11 +/- 1.07), and (1.42 +/- 0.35) mm2 respectively] and in inflammation area (0.22 , 0.21, and 0.09 mm2, respectively). Bivariate correlation analysis showed that the inflammation area was positively correlated with the neointimal area (P < 0.001, correlation coefficient = 0.719). When stent type, mean injury score, and EEL area were adjusted, partial correlations analysis showed that the inflammation area was still positively correlated with the neointimal area (P = 0.01, correlation coefficient = 0.498).

CONCLUSIONInflammation promotes the neointimal proliferation after coronary stent implantation. Sirolimus-eluting stent may reduce the inflammatory response.

Animals ; Coronary Vessels ; pathology ; Drug-Eluting Stents ; adverse effects ; Inflammation ; pathology ; Neointima ; pathology ; Stents ; adverse effects ; Swine ; Swine, Miniature ; Tunica Intima ; pathology

OBJECTIVEThe aim of this study was to investigate the mechanism and efficacy of tetramethylpyrazine-eluting stents (TES) on inhibiting neointima formation in porcine coronary arteries.

METHODSTES was prepared by tetramethylpyrazine spray-coated in bare metal stents (BMS). Pigs were implanted with TES or BMS (n = 7 each), respectively. Quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) were performed before, immediately after stenting and at 28 days after stenting. Coronary arteries segments (5 cm) before and post stenting area (5 cm) as well as at stenting location were harvested at 28 days post stenting for histopathological examinations (inflammation, vascular smooth muscle cells proliferation and apoptosis).

RESULTSFollow up QCA at 28 days showed that percentage diameter stenosis were significantly lower in the TES group than that in the BMS group [(10.0 +/- 2.1)% vs (60.2 +/- 23.5)%, P = 0.01]. The lumen area determined by IVUS was similar between the two groups and there was no in-stent thrombosis in TES or BMS treated animals. Internal elastic lamina area was significantly larger while the neointimal area [(1.51 +/- 0.45) mm(2) vs (4.60 +/- 1.39) mm(2), P = 0.04] was significantly smaller in the TES group than that in the BMS group. Histopathological assessments showed fewer inflammatory cells in the stented-coronary artery walls than those at the border zones of stenting in both groups. The number of proliferating cells were significantly decreased while apoptotic cells were significantly increased in the TES group compared with the BMS group (all P < 0.05).

CONCLUSIONTES could effectively reduce in-stent restenosis in this porcine model by attenuating vascular smooth muscle proliferation and enhancing vascular smooth muscle apoptosis post stenting.

Animals ; Coronary Restenosis ; prevention & control ; Coronary Vessels ; pathology ; Disease Models, Animal ; Double-Blind Method ; Drug-Eluting Stents ; Pyrazines ; administration & dosage ; Swine ; Tunica Intima ; drug effects ; pathology

To assess the effect of a NO-eluting stent on reducing neointimal thickening in a porcine coronary artery stent injury model, sodium nitroprusside (SNP), a NO donor, was incorporated into polyurethane (PU) polymer and coated onto metallic coil stents, and two types of stents with thin and thick barrier coatings were characterized. In vivo biological activity of the NO-eluting stents was assessed by measurement of coronary arterial cGMP levels in 32 pigs/64 arteries at days 1, 2, 7 and 14. Morphometric analyses were performed in 16 pigs to determine the effect of NO-eluting stents on neointimal hyperplasia 28 days following arterial injury. The SNP-coated stents released NO in a controlled manner for up to 4 weeks in the in vitro experiments and an increase in local tissue cGMP levels was demonstrated for up to 14 days. The neointimal area at 28 days was not diminished, however, by NO eluded from either stents of thin or thick barriers (control bare stent - 0.66 mm2, control PU stent - 0.68 mm2, SNP-PU thin coating stent - 0.78 mm2, SNP-PU thick coating stent - 0.85 mm2; all p=NS). In conclusion, the SNP-coated polymer stent exerted a local biological effect on the arterial wall, with sustained elevation of cGMP level. Although local delivery of NO from this device did not reduce neointimal hyperplasia in this porcine model, this polymer-coated stent might be a promising tool for administration of other agents that may modify the reparative tissue responses leading to restenosis.
Animal ; Coated Materials, Biocompatible ; Coronary Vessels/*injuries ; Nitric Oxide/*administration & dosage/pharmacology ; *Stents ; Swine ; Tunica Intima/*drug effects ; Wounds and Injuries/*pathology

OBJECTIVETo evaluate the short- and long-term prevalence of persistent uncovered struts and in-stent thrombus after sirolimus-eluting stent (SES) implantation by optical coherence tomography (OCT).

METHODSOCT was performed for 31 SES in 21 patients at 3 months and for 30 SES in 21 patients at 2 years post SES implantation. Thickness of new intima inside each strut was measured and thickness equal to 0 microm was defined as an uncovered strut. Existence of in-stent thrombus was also evaluated.

RESULTSA total of 4545 struts and 3707 struts were evaluated at 3 months and at 2 years post SES implantation, respectively. New intima at 2 years was significantly thicker than that at 3 months [(71 +/- 93) microm vs. (29 +/- 41) microm, P < 0.01]. Percent of uncovered struts at 2 years was significantly lower than that at 3 months (5% vs. 15%, P < 0.01). Prevalence of uncovered struts was similar at 2 years and at 3 months (81% vs.95%, P > 0.05). Subclinical thrombus was recognized in 14% patients at 3 months and 2 years post SES implantation.

CONCLUSIONSNeointimal coverage inside the SES is a continuous process and the number of uncovered struts decreased from 3 months to 2 years after SES implantation. Few uncovered struts could still be visualized in the majority of patients at 2 years post SES implantation.

Aged ; Drug-Eluting Stents ; adverse effects ; Female ; Humans ; Male ; Middle Aged ; Thrombosis ; diagnosis ; etiology ; pathology ; Tomography, Optical Coherence ; methods ; Tunica Intima ; pathology

BACKGROUNDPost-stenting restenosis is a significant clinical problem, involving vascular smooth muscle cells (VSMCs) proliferation and apoptosis. It is reported that c-myc antisense oligodeoxynucleotides (ASODNs) local delivered by catheter can inhibit VSMCs proliferation. This study was designed to assess tissue distribution of c-myc ASODN local delivered using gelatin-coated platinum-iridium (Pt-Ir) stents, and its effect on apoptosis of VSMCs.

METHODSGelatin-coated Pt-Ir stents that had absorbed caroboxyfluorescein-5-succimidyl ester (FAM) labeled c-myc ASODNs (550 microg per stent) were implanted into the right carotid arteries of 6 rabbits. Tissue samples were obtained at 45 minutes, 2 hours, and 6 hours. Tissue distribution of c-myc ASODNs was assessed by fluorescence microscopy. In addition, 32 rabbits were randomly divided into two groups. Rabbits in the control group (n = 16) were implanted with gelatin-coated Pt-Ir stents, and those in the treatment group (n = 16) were implanted with gelatin-coated stents that had absorbed c-myc ASODNs. 7, 14, 30, or 90 days (n = 4, respectively, for each group) after the stenting procedure, the stented segments were harvested, and histopathological examinations were performed to calculate neointimal area and mean neointimal thickness. The expression of c-myc was assessed using in situ hybridization (ISH) and immunohistochemical methods. Apoptotic VSMCs were detected using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope (TEM).

RESULTSAccording to fluorescence microscopic results, FAM-labeled c-myc ASODNs were concentrated in the target vessel media at the 45 minutes time point, and then dispersed to the adventitia. Morphometric analysis showed that neointimal area and mean neointimal thickness increased continuously up to 90 days after stent implantation, but that total neointimal area and mean neointimal thickness were less in the treatment group than in the control group at all time points (P < 0.0001). At day 7 and day 14 after stenting, there were no detectable apoptotic cells in either group. However, apoptotic cells were present in the neointima 30 and 90 days after stenting, and the number of apoptotic cells was less at 30 days than at 90 days. Meanwhile, c-myc ASODNs appeared to induce apoptosis in more cells in the treatment group than that in the control group. Typical apoptotic VSMCs were observable under TEM. The expression of c-myc was positive in the control group and negative or weakly positive in the c-myc ASODN treatment group, according to both ISH and immunohistochemical examination.

CONCLUSIONGelatin-coated Pt-Ir stent mediated local delivery of c-myc ASODNs is feasible. The localization of c-myc ASODN is primarily in the target vessel walls. c-myc ASODNs can inhibit VSMCs proliferation and induce its apoptosis after local delivery in vivo.

Animals ; Apoptosis ; drug effects ; Carotid Arteries ; Female ; Gelatin ; Genes, myb ; genetics ; In Situ Hybridization ; Iridium ; Male ; Microscopy, Fluorescence ; Myocytes, Smooth Muscle ; pathology ; Oligodeoxyribonucleotides, Antisense ; administration & dosage ; metabolism ; pharmacology ; Platinum ; Rabbits ; Random Allocation ; Stents ; Tissue Distribution ; Tunica Intima ; metabolism ; Tunica Media ; metabolism

OBJECTIVETo observe the effects of Tongguan Capsule on the mobilization and differentiation of bone marrow mononuclear cells (BMMNCs) to the injured carotid arteries.

METHODSThe rat model of injured carotid arteries was established. Mononuclear cells were separated from the bone marrow of donor rats, which were labeled by PKH 26 and then injected through the tail vein to the recipient rats with injured carotid arteries. The rats were randomly divided into two groups. Tongguan Capsule suspension was administered by gastrogavage to rats in the experiment group, while equal volume of normal saline was given to rats in the control group. Four weeks later the injured carotid arteries were harvested and frozen sections were made to observe the differences of intima area/media area ratio (Ai/Am). The difference of BMMNCs migrating to the injured carotid arteries between the two groups was observed under fluorescence microscope. The difference of the vascular endothelial growth factor (VEGF) and stromal derived factor-1 (SDF-1) levels in serum were detected by ELISA.

RESULTSThe PKH 26 labeled cells appeared in the experiment group, while only little scattered fluorescent light points was presented in the control group. The intima area and the ratio of Ai/Am of the experiment group decreased more obviously than that of the control group (P<0.01). Two and 4 weeks later the VEGF and SDF-1 levels in serum of the experiment group were more obviously enhanced than those of the control group (P<0.01).

CONCLUSIONTongguan Capsule could promote the BMMNCs transplanting towards the intima of injured carotid arteries, and take part in the repair of the intima of injured carotid arteries.

Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; drug effects ; Chemokine CXCL12 ; blood ; Drugs, Chinese Herbal ; pharmacology ; Endothelium, Vascular ; Monocytes ; cytology ; drug effects ; Rats ; Rats, Wistar ; Tunica Intima ; cytology ; drug effects ; pathology ; Vascular Endothelial Growth Factor A ; blood

Tanshinone IIA nanoparticles were constructed and perfused in rabbit's right carotid after intimal denudation with ballon. Localization and retention at different time points of the coumarin-labeled drug nanoparticles were evaluated under laser confocal microscope. Nanoparticles were seen in the three layers of the cross-section artery. At 7 days, they were mainly deposited in the medial layer, while the deposition was generally observed in the adventitia and media at 14 days and 28 days. In the Tanshinone IIA nanoparticle study, a significant reduction of the neo-intimal hyperplasia was noted by comparing the intimal area and the intima-media ratio in the three groups. And the PLGA nanoparticles appeared to be fully biocompatible. As a result, the local administration of the nanoparticles with incorporated Tanshinone IIA showed not only the preventive effects, but aslo the high absorption and good biocompatability in the whole arterial wall.
Angioplasty, Balloon ; adverse effects ; Animals ; Caprolactam ; administration & dosage ; analogs & derivatives ; Carotid Arteries ; pathology ; Diterpenes, Abietane ; Drug Carriers ; Hyperplasia ; etiology ; prevention & control ; Lactic Acid ; administration & dosage ; Nanoparticles ; Phenanthrenes ; administration & dosage ; pharmacology ; Polyesters ; Polymers ; administration & dosage ; Rabbits ; Tunica Intima ; drug effects ; pathology