Expression of Versican and Its Related Molecules in Patient with Multiple Myeloma and Its Clinical Significance / 中国实验血液学杂志

OBJECTIVE@#To investigate the expression and clinical significant of VCAN and its related molecules in patients with MM.@*METHODS@#Ficoll density gradient centrifugation method was used to speared the bone marrow mononuclear cell in 25 cases of MM before and after treatment, the relative mRNA expression of VCAN and their related molecules (FAK, FN, MK, and HAS) in bone marrow was detected by real-time quantitative PCR, and their protein expression was determined by Western bolt.@*RESULTS@#The expression of VCAN, FK and FN in the effective group after treatment was significantly lower than that before treatment (P＜0.05), however, the expression of MK and HAS showed no statistically significantly different before and after treatment (P＜0.05). The expression of VCAN of patients in non remission group was significantly higher than that in control group (P＜0.05). The expression of FAK and FN of patients in no remission group was significant increased as compared with the patients in newly diagnosed group (P＜0.05). The relative expression of VCAN mRNA in the patients at 3rd stage was significantly higher than those at the 1st stage (P＜0.05) and control group but showed no significant difference to the patients at 2nd stage (P＜0.05). The expression of VCAN and its related proteins (FAK, MK, FN) showed positively correlation in bone marrow mononuclear cells of MM patients (P＜0.05). The correlation between VCAN and HAS was not statistically significant (r=0.259，P＞0.05). Survival analysis showed that the relative expression of VCAN mRNA was associated with OS (P=0.049) and PFS (P=0.041) in MM patients.@*CONCLUSION@#VCAN and its related molecules are highly expressed in MM patients; VCAN may act as potential biomarker in the development of multiple myeloma.

Effect of antibacterial peptide hCAP18/LL-37 on ovarian cancer microenvironment and the regulatory mechanism of its expression / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effect of antibacterial peptide hCAP18/LL-37 on ovarian cancer microenvironment and the regulatory mechanism of its expression.</p><p><b>METHODS</b>We assessed the effect of macrophage-promoted ovarian cancer cells invasion using BioCoat Matrigel invasion chamber. The expressions of hCAP18/LL-37 and versican V1 were determined by real-time PCR and Western blot analysis. SKOV3 cells were transfected with shRNA plasmid to abrogate the expression of versican V1, and then the expression of hCAP18/LL-37 in macrophages and the invasiveness of SKOV3 cells were assayed.</p><p><b>RESULTS</b>The Matrigel invasion assay showed that after co-culture with macrophages for 4 days, the number of penetrated SKOV3 cells was 112.8±17.1/per high power field, significantly higher than that in the SKOV3 cells cultured alone (8.2±1.9/per high power field) (P<0.05). Addition of hCAP/LL-37 neutralizing antibody into the co-cultured macrophage-SKOV3 cells markedly inhibited the macrophage-promoted SKOV3 cells invasion. The penetrated SKOV3 cells was 22.2±5.6/per high power field, significantly lower than the 100.6±25.2/per high power field in the control macrophage- SKOV3 co-cultured cells (P<0.05). The expressions of hCAP18/LL-37 mRNA and protein in macrophages were remarkably enhanced upon co-culture with SKOV3 cells, but not changed in SKOV3 cells cultured alone. The expression and secretion of versican V1 in the ovarian cancer cells were also significantly increased after co-cultured with macrophages. Knockdown of versican V1 in SKOV3 cells by small interfering RNA significantly reduced the expression of hCAP18/LL-37 mRNA and protein in the macrophages, as well as decreased the invasiveness of SKOV3 cells (P<0.05).</p><p><b>CONCLUSIONS</b>In the cancer microenvironment, the macrophage-secreted hCAP18/LL-37 promote the invasiveness of ovarian cancer cells, and the hCAP18/LL-37 expression is regulated by versican V1 protein released by ovarian cancer cells.</p>

Expression of Versican and its clinical significance in gastric carcinoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the expression of Versican in gastric carcinoma and its relationship with tumor angiogenesis.</p><p><b>METHODS</b>Protein expression of Versican, vascular endothelial growth factor and CD34 was evaluated by immunohistochemistry (EliVision method) in 80 cases of gastric carcinoma and 30 samples of normal gastric tissue.</p><p><b>RESULTS</b>There were statistically significant differences in the expression of Versican, vascular endothelial growth factor and CD34 between gastric carcinoma and normal gastric tissue (P < 0.05). The expression of Versican was seen mainly in fibroblasts of the tumor and was correlated with tumor differentiation, clinical stage and lymph node metastasis (P < 0.05), whereas vascular endothelial growth factor was primarily seen in the cytoplasm of the tumor cells and correlated with tumor differentiation, clinical stage, Lauren classification and lymph node metastasis (P < 0.05). MVD was correlated with tumor differentiation, clinical stage, Lauren classification, depth of tumor invasion and lymph node metastasis (P < 0.05). In addition, positive correlation of Versican and VEGF protein expression was found in tumor cells (r = 0.467, P < 0.01).</p><p><b>CONCLUSION</b>The expression of both Versican and vascular endothelial growth factor is closely associated with tumor angiogenesis in gastric carcinoma.</p>

Expression of carbonic anhydrase IX in human fetal joints, ligaments and tendons: a potential marker of mechanical stress in fetal development? / 대한해부학회지

Carbonic anhydrase type IX (CA9) is known to express in the fetal joint cartilage to maintain pH against hypoxia. Using paraffin-embedded histology of 10 human fetuses at 10-16 weeks of gestation with an aid of immunohistochemistry of the intermediate filaments, matrix components (collagen types I and II, aggrecan, versican, fibronectin, tenascin, and hyaluronan) and CA9, we observed all joints and most of the entheses in the body. At any stages examined, CA9-poisitive cells were seen in the intervertebral disk and all joint cartilages including those of the facet joint of the vertebral column, but the accumulation area was reduced in the larger specimens. Glial fibrillary acidic protein (GFAP), one of the intermediate filaments, expressed in a part of the CA9-positive cartilages. Developing elastic cartilages were positive both of CA9 and GFAP. Notably, parts of the tendon or ligament facing to the joint, such as the joint surface of the annular ligament of the radius, were also positive for CA9. A distribution of each matrix components examined was not same as CA9. The bone-tendon and bone-ligament interface expressed CA9, but the duration at a site was limited to 3-4 weeks because the positive site was changed between stages. Thus, in the fetal entheses, CA9 expression displayed highly stage-dependent and site-dependent manners. CA9 in the fetal entheses seemed to play an additional role, but it was most likely to be useful as an excellent marker of mechanical stress at the start of enthesis development.

Association of single nucleotide polymorphisms of CSPG2 and HSPG2 genes with intracranial aneurysm in ethnic Han Chinese population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the association between CSPG2 and HSPG2 gene polymorphisms and intracranial aneurysm (IA) in ethnic Han Chinese population.</p><p><b>METHODS</b>A case-control study was carried out. A total of 537 IA patients and 1071 normal controls with matched age and gender were recruited. Peripheral blood samples were obtained from all subjects. Following extraction, target DNA was amplified with PCR and genotyped with a SNaPshot method. The association between 2 tag SNPs (rs251124 and rs3767137) of CSPG2 and HSPG2 genes and IA was assessed.</p><p><b>RESULTS</b>The genotype frequencies of rs251124 and rs3767137 were both in Hardy-Weinberg equilibrium. No significant difference has been found in the frequencies of rs251124 of CSPG2 between the two groups. Similarly, the frequency of rs3767137 (HSPG2) did not differ between the IA and control groups (P=0.22), albeit with an OR value of greater than 1 (OR=1.12, 95%CI=0.92-1.37). There were no significant difference in genotypic frequencies of the two SNPs between the two groups (P=0.46, 0.53).</p><p><b>CONCLUSION</b>No association has been found between polymorphisms of rs251124 and rs3767137 loci of CSPG2 and HSPG2 genes and IA in the selected population.</p>

Influencia de componentes de la matriz extracelular en la agresividad y potencial invasor del cáncer cérvicouterino: ¿Qué hay de nuevo? / Influence of extracellular matrix components in aggressiveness and invasive potential of cervical cancer: What's new?

El cáncer cérvico uterino (CCU) es una patología de alta incidencia y mortalidad. La investigación hasta ahora se ha enfocado en estudiar su asociación con virus papiloma. Sin embargo, el estudio de la matriz extracelular (MEC) ha dado una nueva perspectiva para el estudio de factores inductores o perpetuadores de las neoplasias. En las neoplasias epiteliales como CCU el estroma tumoral presenta una composición dinámica de elementos celulares, destacando la presencia de miofibroblastos positivos a alfa actina de músculo liso (alfa SMA+) y fibrocitos CD34+. La MEC tiene un papel fundamental, ya que no sólo otorga las condiciones apropiadas para el desarrollo del tumor, sino que además condiciona el fenotipo de la población celular del estroma, donde la pérdida de fibrocitos CD34+ asociada a una ganancia de miofibroblastos alfa SMA+ podría ser un indicador muy sensible de invasión estromal, incluso en estadios iniciales. De la misma forma lo hace TGF-beta Ι, ya que su presencia es un reflejo de la síntesis de alfa SMA. Un nuevo elemento es versicán, un proteoglicano cuyas isoformas V0 y V1 se expresan también en tejidos neoplásicos de tumores ováricos, mama y cerebro, entre otros. Desempeña un papel muy importante en los fenómenos de adhesión celular, proliferación, migración y ensamblaje a la MEC. Por lo tanto, el análisis del estroma adyacente a las lesiones epiteliales del cuello uterino puede complementar el conocimiento sobre la conducta biológica de éstas, constituyendo una poderosa herramienta diagnóstica, de forma complementaria a los elementos utilizados hasta ahora.

Squamous cell carcinoma of the cervix (SCC) is a pathology that has high incidence and mortality. So far, research has been focused in the study of its association with papilloma virus. However, knowledge about extracellular matrix (ECM) has given a new perspective for the study of factors that induce or perpetuate neoplasms. In epithelial neoplasms like SCC, the tumoral stroma exhibits a dynamic composition of cellular elements, highlighting the presence of alpha actin of smooth muscle positive myofibroblasts (alpha SMA+) and CD34+ fibrocytes. ECM has an essential role, because it not only provides the appropriate conditions for tumor's development, but also affects stromal cell population phenotype, where a loss of CD34+ fibrocytes associated with a gain of alpha SMA+ myofibroblasts could be a sensitive indicator of stromal invasion, even in early stages. TGF-beta Ι does it in the same way, as its presence is a reflection of the synthesis of alpha SMA+. A new element is versican, a proteoglycan whose V0 and V1 isoforms expression is also observed in neoplastic tissues of ovary, breast and brain tumors, among others. It plays an important role in the phenomena of cellular adhesion, proliferation, migration and assembly of the ECM. Therefore, the analysis of the stroma adjacent to epithelial injuries of the cervix can complement the knowledge about the biological conducts of these, constituting a powerful diagnostic tool, as a complement to the elements used nowadays.

The Effects of TWEAK, Fn14, and TGF-beta1 on Degeneration of Human Intervertebral Disc

OBJECTIVE: The purpose of this study is to explain the effect and reciprocal action among tumor necrosis factor (TNF) like weak inducer of apoptosis (TWEAK), fibroblast growth factor-inducible 14 (Fn14), and transforming growth factor-beta1 (TGF-beta1) on degeneration of human intervertebral disc (IVD). METHODS: Human intervertebral disc tissues and cells were cultured with Dulbecco's Modified Eagle's Medium/Nutrient F-12 Ham (DMEM/F-12) media in 37degrees C, 5% CO2 incubator. When IVD tissues were cultured with TWEAK, Fn14 that is an antagonistic receptor for TWEAK and TGF-beta1, the level of sulfated glycosaminoglycan (sGAG) was estimated by dimethyl methyleneblue (DMMB) assay and sex determining region Y (SRY)-box 9 (Sox9) and versican messenger ribonucleic acid (mRNA) levels were estimated by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: When human IVD tissue was cultured for nine days, the sGAG content was elevated in proportion to culture duration. The sGAG was decreased significantly by TWEAK 100 ng/mL, however, Fn14 500 ng/mL did not change the sGAG production of IVD tissue. The Fn14 increased versican and Sox9 mRNA levels decreased with TWEAK in IVD tissue TGF-beta1 20 ng/mL elevated the sGAG concentration 40% more than control. The sGAG amount decreased with TWEAK was increased with Fn14 or TGF-beta1 but the result was insignificant statistically. TGF-beta1 increased the Sox9 mRNA expression to 180% compared to control group in IVD tissue. Sox9 and versican mRNA levels decreased by TWEAK were increased with TGF-beta1 in primary cultured IVD cells, however, Fn14 did not show increasing effect on Sox9 and versican. CONCLUSION: This study suggests that TWEAK would act a role in intervertebral disc degeneration through decreasing sGAG and the mRNA level of versican and Sox9.

Estudo histológico da matriz extracelular do músculo cricofaríngeo em cadáveres de diferentes idades / Extracellular matrix composition of the cricopharyngeus muscle

O músculo cricofaríngeo desempenha um importante papel na deglutição. Acredita-se que seu comportamento elástico seja dependente não apenas do componente muscular, mas também do tecido conectivo intramuscular. O objetivo desse estudo foi analisar a presença e a distribuição do colágeno total, colágenos tipo I e III, fibras elásticas, fibronectina e versican no endomísio do músculo cricofaríngeo em cadáveres de diferentes idades. Vinte e sete músculos foram obtidos mediante autópsia de indivíduos de ambos os sexos com idades entre 28 e 92 anos. Foram realizadas colorações histoquímicas, Método Picrossírius e Método Resorcina-fuccina com oxidação prévia pela oxona, e imunoistoquímicas, para colágeno tipo I, tipo III, fibronectina e versican. A medida dos elementos estudados foi feita por meio de um sistema de análise de imagens que incluía um microscópio, conectado a um computador por meio de uma câmera de vídeo. Foi utilizado o software Image pro Plus, versão 4.1. Para cada caso, quinze imagens não sobrepostas de cada coloração no aumento de 400x foram analisadas. A área de marcação positiva dentro do endomísio do músculo cricofaríngeo foi determinada por um padrão de cor específico para cada coloração. A área de cada elemento da matriz extracelular foi expressa como porcentagem da área total do estudada. Os dados foram expressos em medianas e intervalos interquartílicos. A correlação entre idade e os diferentes elementos da matriz extracelular foi realizada por meio da correlação de Spearman. O teste de Mann-Whitney para distribuição não paramétrica foi utilizado para comparar as áreas porcentuais e os indivíduos de diferente sexo. Todos os testes foram realizados pelo software SPPS versão 13.0 e foi admitido um calor de significância com p < 0,05.

The cricopharyngeus muscle is thought to play an important role in swallowing and related activities. Its elastic behavior is likely to depend not only on its muscular components, but also on the intramuscular connective tissue. Our objective is to analyze the presence and distribution of total collagen, type I and III collagen, elastic fibers, fibronectin and versican in cricopharyngeus muscle endomysium in adults of a wide age range. Twenty-seven cricopharyngeus muscles obtained from male and female cadavers (age range, 28-92 years-old) were analyzed with the Picrosirius method, oxidized Weigert resorcin-fuchisin, immunohistochemistry. Quantification of stained areas in the cricopharyngeus endomysium with different techniques was performed by an image analysis system connected to a light microscope. The correlation between age and the density of different extracellular matrix proteins was tested using Spearman test. T-tests for independent samples were used to analyze the influence of gender and smoking habit on the fractional areas of extracellular matrix. Collagens had the highest density among the analyzed components. Elastic fibers surrounded each muscle cell, longitudinal to their long axis, associated to traversing fibers, forming a fiber network embedding muscle cells. There was a wide variation on fibronectin and versican content among cases. There were no statistical significance for analysis made between those components of extracellular matrix and age andgender. Our findings suggest that presence and distribution of these extracellular matrix components are important to cricopharyngeus muscle homeostasis. The elastic fibers arrangement can contribute for the cricopharyngeus muscle elastic behavior and ability to rapidly reassume its tonic position after opening during swallows. Variations in the expression of fibronectin and versican can beresultant of its injury susceptibility. The absence of changes on extracellular components during aging could mean that cricopharyngeus muscle is not susceptible to similar age changes as other skeletal muscles.

Análise mecânica e histológica do tegumento facial com seqüela de queimadura após tratamento tópico com tretinoína / Mechanical and histological analysis of the facial skin with burn sequelae after tretinoin topical treatment

Pacientes vítimas de queimaduras convivem com seqüelas que podem diminuir sua auto-estima e qualidade de vida. Vítimas de queimaduras faciais são excluídos social e profissionalmente solicitando ao cirurgião plástico tratamentos complementares aos cirúrgicos para melhoria da aparência e qualidade da pele. Quinze pacientes do sexo feminino, vítimas de queimadura facial por álcool com mais de dois anos de evolução, foram submetidas a tratamento tópico com tretinoína 0,05% durante um ano, com exceção da região pré-auricular. Após este período, duas biópsias faciais, uma na região pré-auricular e outra um centímetro abaixo do lóbulo da orelha, foram realizadas para comparar áreas não tratadas e tratadas. Os fragmentos biopsiados foram submetidos à análise mecânica e histológica. Medidas de resistência e elastância foram significativamente menores nas áreas tratadas (resistência p=0,03 e elastância p<0,05). Não houve diferença estatística entre as densidades de fibras colágenas totais e de colágeno tipo III, fibras elásticas e versicam nas áreas tratadas e não tratadas...

Patients that are victims of burns live with sequelae that may decrease their self-esteem and quality of life. Victims of facial burns are excluded from social and professional life. They request the plastic surgeon to provide complementary treatment to the surgical one, so as to improve their appearance and the quality of the skin. Fifteen female patients, victims of facial burns caused by alcohol with more than two years of evolution, underwent topical treatment with 0.05% tretinoin during one year. During this period, a small area at the pre-auricular region was spared from the treatment. After this period two facial biopsies, one in the pre-auricular area and the other one, 1 cm below the ear lobe, were performed to compare treated and non treated areas. Skin strips underwent a mechanical and histological analysis. Measurements of resistance and elasticity were significantly lower in the treated skin as compared with non-treated skin (resistance, p=0.03 and elasticity, p<0.05). The density of collagen and collagen type III fibers, elastic fibers and versican was not significantly different between treated and non-treated skins...

Distribuição do colágeno tipo I, colágeno tipo III e versican na lâmina própria da prega vocal humana de fetos e adultos: método histoquímico e imunoistoquímico / Collagen type I, collagen type III and versican distribution within the lamina propria of fetal and adult human vocal fold: histochemical and immunohistochemical method

A matriz extracelular apresenta importante papel na fisiologia da fonação sendo necessário o conhecimento de seus componentes. Poucos estudos sobre os componentes da matriz em fetos e a ausência de relatos do versican nesta faixa etária, bem como a necessidade de aprofundar os conhecimentos sobre os componentes da matriz em adultos, resultaram na elaboração deste estudo. Analisar a presença e distribuição do colágeno tipo I, colágeno tipo III e proteoglicano versican na lâmina própria da prega vocal de laringes fetais e adultas é o objetivo do estudo. No grupo fetal foram estudadas 7 laringes obtidas de cadáveres variando de 28 a 36 semanas de idade gestacional. No grupo adulto foram estudadas 20 laringes, 10 do sexo masculino, com média de idade de 66 anos, e 10 do sexo feminino com média de idade de 70 anos, com idades pareadas. Utilizou-se método imunoistoquímico para avaliar a expressão do versican no grupo fetal e adulto. Para a avaliação das fibras colágenas utilizou-se o método da Picrosirius polarização no grupo fetal e imunoistoquímico no grupo adulto. A quantificação das fibras colágenas e do versican foi realizada por meio de análise digital de imagens. Os resultados do grupo fetal mostraram uma distribuição homogênea das fibras colágenas formando uma estrutura monolaminar com um entrelaçamento entre as fibras denominado arranjo em cesta de vime; em relação ao versican, este apresentou uma densidade maior na camada superficial e intermediária da lâmina própria. Os resultados do grupo adulto mostraram uma menor densidade de colágeno tipo I na camada intermediária quando comparado à camada superficial (p<0.001) e camada profunda (p=0.005). O colágeno tipo III apresentou distribuição mais homogênea nas camadas da lâmina própria, com uma densidade estatisticamente menor na camada intermediária quando comparada à camada profunda (p=0.001), mas sem diferença estatística na camada superficial. O versican apresentou densidade menor na camada superficial...

Extracellular matrix has an important rule in the vocal fold physiology and the knowledge about your components is necessary. Fewer studies about matrix extracellular and no studies about versican in fetuses, and the necessity to improve the knowledge about extracellular matrix components in adults group came us to the elaboration of this study that has the objective to analyze the presence and distribution of collagen type I, type III and versican in human vocal fold lamina propria of fetal and adult larynges. Seven fetal larynges obtained from 28- to 36- week-old cadaveric fetuses were studied. Twenty larynges were obtained from adults (10 males and 10 females). Mean age of males was 66 and 70 from females, without significant statistical difference between groups. For the analysis of versican expression, immunohistochemical reactions were carried out in fetal and adult group. The larynges were analyzed through Picrosirius polarization method and immunohistochemistry to visualize the collagen fibers, in fetal and adult group respectively. Collagen fibers and proteoglycan were quantified using a digital image analysis system. In fetuses, the collagen fibers system exhibited homogeneous distribution pattern in a monolaminar layer and spatial arrangement as in a wicker basket; predominance of versican distribution was found out on the superficial and intermediate layer of vocal fold lamina propria. In adult group, there was a lower collagen type I density in the intermediate layer when compared to the superficial (p<0.001) and the deep layers (p=0.005). Collagen type III presented a lower density in the intermediate layer when compared to the deep layer (p=0.001) but without differences in the superficial layer. There was a lower versican density in the superficial layer when compared to the intermediate layer (p=0.036) and deep layer (p=0.013). There was a lower versican density in the lamina propria of females when compared with males...

The Relation Between Sox9, TGF-beta1, and Proteoglycan in Human Intervertebral Disc Cells

OBJECTIVE: The aim of this study is to elucidate the effects of transforming growth factor-beta (TGF-beta)1 and L-ascorbic acid on proteoglycan synthesis, and the relationship between Sox9, proteoglycan, and TGF-beta1 in intervertebral disc cells. METHODS: Human intervertebral disc tissue was sequentially digested to 0.2% pronase and 0.025% collagenase in DMEM/F-12 media and extracted cells were cultured in 37degrees C, 5% CO2 incubator. When intervertebral disc cells were cultured with TGF-beta1 or L-ascorbic acid, the production level of sulfated glycosaminoglycan (sGAG) was estimated by dimethyl methyleneblue (DMMB) assay. The changes of Sox9 mRNA and protein levels via TGF-beta1 were detected by RT-PCR and Western blot analysis in each. RESULTS: The amount of sGAG was increased with the lapse of time during incubation, and sGAG content of pellet cultured cells was much larger than monolayer culture. When primary cultured intervertebral disc cells in monolayer and pellet cultures were treated by TGF-beta1 20 ng, sGAG content of experimental group was increased significantly compared to control group in both cultures. L-Ascorbic acid of serial concentrations (50-300 ug/ml) increased sGAG content of mono layer cultured intervertebral disc cells significantly in statistics. The co-treatment of TGF-beta1 and L-ascorbic acid increased more sGAG production than respective treatment. After treating with TGF-beta1, Sox9 mRNA and protein expression rates were significantly increased in disc cells compared with the control group. CONCLUSION: This study suggests that TGF-beta1 would increase sulfated glycosaminoglycan (sGAG) and other proteoglycans such as versican by elevating Sox9 mRNA and protein expressions in order.

Histopathological Characteristics of Human Coronary Stent Restenosis

BACKGROUND AND OBJECTIVES: Neointimal ingrowth rather than stent recoil is thought to be important for coronary in-stent restenosis. However only limited pathologic data are available to adress the mechanisms of in-stent restenosis. With the specific aim of measuring cell replication and of assessing cellularity and extracellular matrix (ECM) composition, we analyzed atherectomized coronary arterial in-stent restenotic specimens. METHODS AND RESULTS: In the present study, we analyzed 29 atherectomized coronary arterial in-stent restenotic tissue samples (14 LAD, 10 RCA, and 5 LCX) retrieved from 25 patients (m/f:18/7: age 59+/-13 yr) at 0.5-23 (mean 5.7) months after deployment of Palmaz-Schatz stent. Histopathological analysis of cellular components and ECM was performed using H & E, modified Movat pentachrome, and immunocytochemical staining. Cellular proliferation rate, as estimated by use of antibodies to Ki-67 nuclear antigen showed low proliferation rate with the range of 0-4%, and no positive cells were found in 62% of cases. Myxoid tissue having ECM enriched with versican and hyaluronan was found in 69% of cases, and decreased over time after stenting. Foci of cell poor area were found in 57% of cases, and could be classified into as: (1) containing collagen-rich ECM and (2) containing a proteoglycan-rich ECM. Versican, biglycan, perlecan, and hyaluronan were identified with varying individual distributions in the proteoglycan rich area. Specimens with foci of cell poor area tended to increase over time after stenting (31% in & 4 mo vs. 81% in > or =4 mo after stenting, p<0.01). alpha-smooth muscle actin staining identified the majority of cells as smooth muscle cells (SMC) and occasional macrophages (< or =12 cells per section) were detected by CD68 antibody. CONCLUSIONS: These data suggest that enhanced ECM accumulation rather than cell proliferation may be important mechanisms for stent restenosis. Angioplasty of stent restenosis may therefore fail due to transient compression of this hygroscopic matrix.