Cohort profile: the ESC EURObservational Research Programme Non-ST-segment elevation myocardial infraction (NSTEMI) Registry

AIMS

The European Society of Cardiology (ESC) EURObservational Research Programme (EORP) Non-ST-segment elevation myocardial infarction (NSTEMI) Registry aims to identify international patterns in NSTEMI management in clinical practice and outcomes against the 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without ST-segment-elevation.

METHODS AND RESULTS

Consecutively hospitalised adult NSTEMI patients (n = 3620) were enrolled between 11 March 2019 and 6 March 2021, and individual patient data prospectively collected at 287 centres in 59 participating countries during a two-week enrolment period per centre. The registry collected data relating to baseline characteristics, major outcomes (in-hospital death, acute heart failure, cardiogenic shock, bleeding, stroke/transient ischaemic attack, and 30-day mortality) and guideline-recommended NSTEMI care interventions: electrocardiogram pre- or in-hospital, pre-hospitalization receipt of aspirin, echocardiography, coronary angiography, referral to cardiac rehabilitation, smoking cessation advice, dietary advice, and prescription on discharge of aspirin, P2Y12 inhibition, angiotensin converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB), beta-blocker, and statin.

CONCLUSION

The EORP NSTEMI Registry is an international, prospective registry of care and outcomes of patients treated for NSTEMI, which will provide unique insights into the contemporary management of hospitalised NSTEMI patients, compliance with ESC 2015 NSTEMI Guidelines, and identify potential barriers to optimal management of this common clinical presentation associated with significant morbidity and mortality.

Predictors of clinical success after transcatheter para-valvular leak closure: an international prospective multicentre registry

Background

Prosthetic paravalvular leaks (PVLs) are associated with congestive heart failure and haemolysis, for which the standard treatment is open-heart surgery with the attendant risks to the patient. Transcatheter closure has emerged as an alternative. Patient selection criteria for the best option are needed. We aimed to identify predictors of clinical success after transcatheter PVL closure.

Purpose

We aimed to identify predictors of clinical success after transcatheter PVL closure.

Methods

Consecutive patients referred to 24 European centres for transcatheter PVL closure in 2017–2019 were included in a prospective registry (Fermeture de Fuite ParaProthétique, FFPP). Clinical success was absence of any of the following within 1 month: re-admission for heart failure, blood transfusion, open-heart valvular surgery, and death.

Results

We included 216 symptomatic patients, who underwent 238 percutaneous PVL closure procedures on the mitral (64.3%), aortic (34.0%), or tricuspid (1.7%) valve. The prosthesis was mechanical in 53.3% and biological in 45.3% of procedures. All patients were symptomatic with heart failure, haemolytic anaemia, and the association of both conditions in 48.9%, 7.8% and 43.3%. One, two and three PVL were addressed during the same procedure in 69.6%, 26.6% and 3.8% respectively. Mitral and aortic PVL were severe in 35.3% and 13.8% (p<0.001). PVL was punctiform or extended to 1/8 or 1/4 of valve circumference in 18.6%, 52.4% and 28.1% of cases. A total of 331 devices were implanted. More than one device (up to 5) was implanted in 34.2% of procedures. Vascular plug 3, muscular ventricular septal defect occluder, vascular plug 2 and paravalvular leak device were the most frequently used devices, implanted in 45.0%, 16.0%, 14.2% and 13.6%, respectively. Successful device(s) implantation(s) within the leak and leak reduction ≤ grade 2 occurred in 85.0% and 91.4% of patients with mitral and aortic procedures, respectively (p=0.164), with major intra-procedural adverse event rates of 3.3% and 1.2%, respectively (p=0.371). The clinical success rates were 77.8% and 88.9% following mitral and aortic procedures, respectively (p=0.01). By multivariate logistic regression analysis, technical failure, mechanical valve and haemolytic anaemia were independently associated with absence of clinical success (odds ratios [95% CIs]: 7.7 [2.0–25.0], p=0.002; 3.6 [1.1–11.1], p=0.036 and 3.7 [1.2–11.9], p=0.025; respectively).

Conclusion

Transcatheter PVL closure is efficient and safe in symptomatic patients but is more challenging and associated with an increased risk of clinical failure when performed in patients with hemolysis and/or on a mechanical valve.

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): The study is promoted and financially supported by Groupe Hospitalier Paris Saint Joseph

[Management of non-rhythmic complications of TAVI procedures]

Transcatheter aortic valve (TAVI) is the treatment of choice in patients with severe symptomatic aortic stenosis at high surgical risk. Recent data have also shown favorable results in patients considered to have an intermediate operative risk, which broadens the application of this new technology. Despite its success, the TAVI procedure has been associated with life-threatening complications. Advances in preoperative screening and patient selection have reduced the incidence of these complications. When these complications occur, early recognition and rapid management are essential. The purpose of this review is to describe non-rhythmic mechanical complications attributable to TAVI procedures with their predictive factors, how to prevent and manage them.

Quantitative assessment of skeletal muscle degeneration in patients with myotonic dystrophy type 1 using MRI

PURPOSE

To identify MRI biomarkers that could be used to follow disease progression and therapeutic efficacy in one individual muscle in patients with myotonic dystrophy type 1 (DM1).

MATERIALS AND METHODS

Lower limb MRI and maximal ankle dorsiflexor strength assessment, using a hand-held dynamometer, were performed in 19 DM1 patients and 6 control subjects. The volume of residual muscle tissue of Tibialis Anterior (TA) muscle was chosen as an index for muscle atrophy, and the T2-relaxation-time of the residual muscle tissue was measured to evaluate edema-like lesions. The fat-to-water ratio was assessed using three-point Dixon images to quantify fat infiltration in the entire muscle.

RESULTS

The intra-observer variability of MRI indices (∼5.2% for the residual muscle tissue volume and 2.5% for the fat-to-water ratio) was lower than that of the dorsiflexor torque measurement (∼11.5%). A high correlation (r = 0.91) was found between maximal ankle dorsiflexor strength and residual TA muscle tissue volume in DM1 patients. Increases in the fat-to-water ratio and T2-relaxation-time were associated with a decrease in maximal ankle dorsiflexor strength.

CONCLUSION

MRI appears as a noninvasive method which can be used to follow disease progression and therapeutic efficacy.

Effects of somatostatin and octreotide on the interactions between neoplastic gastroenteropancreatic endocrine cells and endothelial cells: a comparison between in vitro and in vivo properties

BACKGROUND/AIMS

Experimental studies in vitro suggest that somatostatin and some of its analogues used in clinical practice, such as octreotide, may have potent antiangiogenic properties. However, the clinical transposition of these data is difficult.

METHODS

To address this issue, we designed a comparative study of the effects of somatostatin and octreotide on the interactions between neoplastic endocrine cells and endothelial cells in several in vitro and in vivo experimental models, including primary cultures of human umbilical vein endothelial cells (HUVEC), indirect cocultures between HUVEC and the somatostatin-producing endocrine cell line STC-1, and an animal model of intrahepatic dissemination of STC-1 cells.

RESULTS

10(-8)M octreotide markedly inhibited both basal and VEGF-stimulated HUVEC proliferation, had no effect on endothelial cell migration, but inhibited endothelial tubule formation. HUVEC cocultured with the somatostatin- and VEGF-producing STC-1 cells presented a markedly decreased proliferation, a slightly increased motility and an increased capacity of tubule formation; in this system, the inhibition of endothelial cell proliferation was abolished by neutralizing anti-somatostatin but was restored in the presence of anti-VEGF antibodies. This suggests that somatostatin is able to antagonize the effects of VEGF on endothelial cell proliferation but not on endothelial cell sprouting. Finally, no significant effect of octreotide on tumor growth and intratumoral microvascular density was detected in an experimental model of intrahepatic dissemination of STC-1 cells.

CONCLUSION

The in vitro antiangiogenic effects of somatostatin and its analogues are likely to be efficiently counterbalanced in the tumor microenvironment by the concomitant release of proangiogenic factors like VEGF.

VEGF secretion by neuroendocrine tumor cells is inhibited by octreotide and by inhibitors of the PI3K/AKT/mTOR pathway

Gastroenteropancreatic (GEP) endocrine tumors are hypervascular tumors able to synthesize and secrete high amounts of VEGF. We aimed to study the regulation of VEGF production in GEP endocrine tumors and to test whether some of the drugs currently used in their treatment, such as somatostatin analogues and mTOR inhibitors, may interfere with VEGF secretion. We therefore analyzed the effects of the somatostatin analogue octreotide, the mTOR inhibitor rapamycin, the PI3K inhibitor LY294002, the MEK1 inhibitor PD98059 and the p38 inhibitor SB203850 on VEGF secretion, assessed by ELISA and Western blotting, in three murine endocrine cell lines, STC-1, INS-r3 and INS-r9. Octreotide and rapamycin induced a significant decrease in VEGF production by all three cell lines; LY294002 significantly inhibited VEGF production by STC-1 and INS-r3 only. We detected no effect of PD98059 whereas SB203850 significantly inhibited VEGF secretion in INS-r3 and INS-r9 cells only. By Western blotting analysis, we observed decreased intracellular levels of VEGF and HIF-1alpha under octreotide, rapamycin and LY294002. For rapamycin and LY294002, this effect was likely mediated by the inhibition of the mTOR/HIF-1/VEGF pathway. In addition to its well-known anti-secretory effects, octreotide may also act through the inhibition of the PI3K/Akt pathway, as suggested by the decrease in Akt phosphorylation detected in all three cell lines. In conclusion, our study points out to the complex regulation of VEGF synthesis and secretion in neoplastic GEP endocrine cells and suggests that the inhibition of VEGF production by octreotide and rapamycin may contribute to their therapeutic effects.

In-vivo high-resolution X-ray microtomography for liver and spleen tumor assessment in mice

The present study sought to validate the use of glycery1-2-oley-1,3-bis-[7-(3-amino-2,4,6-triiodophenyl)- heptanoate] (DHOG) contrast agent for mouse spleen tumor and liver metastasis imaging by high-resolution X-ray microtomography. Three groups of female nude mice were compared: controls (n = 5), and mice injected with 2.5 x 10(6) STC1 tumor cells in the spleen, imaged at 15 days (group G15, n = 5) and at 30 days (group G30, n = 5, of which one died before imaging). Micro-CT scans (X-ray voltage, 50 kVp; anode current, 200 microA; exposure time, 632 ms; 180 rotational steps resulting in 35 microm isotropic spatial resolution) were acquired at 0, 0.75, 2 and 4 h after i.v. injection of DHOG. CT number (Hounsfield units: HU) and contrast-to-noise ratios (CNR) were determined in three organs. Statistical analysis was performed by Mann-Whitney U-test. Contrast enhancement in normal spleen and liver increased, respectively to 1020 +/- 159 and 351 +/- 27 HU over baseline at 4 h, and 482 +/- 3 and 203 +/- 14 HU on day 6 after a single contrast injection. Automated three-dimensional reconstruction and modeling of the spleen provided accurate and quantifiable images. Spleen tumor and liver metastases did not take up DHOG, making them detectable in contrast to the increased signal in normal tissue. The smallest liver metastasis detected measured 0.3 mm in diameter. High-resolution X-ray micro-CT in living mice using DHOG contrast agent allowed visualization and volume quantification of normal spleen and of spleen tumor and its liver metastases.

Differential involvement of destrin and cofilin-1 in the control of invasive properties of Isreco1 human colon cancer cells

Actin depolymerizing factor (ADF)/cofilin family proteins are key regulators of actin filament turnover and cytoskeleton reorganization. The role of cofilin-1 in cell motility has been demonstrated in several cell types but remained poorly documented in the case of colon cancer. In addition, the putative function of destrin (also known as ADF) had not been explored in this context despite the fact that it is expressed in all colon cancer cell lines examined. We were therefore prompted to evaluate the respective contributions of these proteins to the invasive properties of the human colon cancer Isreco1 cell line, which expresses a comparatively high destrin/cofilin ratio. Reduction of cofilin-1 or destrin expression in Isreco1 cells using RNA interference led to an increase of the number of multinucleated cells and altered polarized lamellipodium protrusion and distribution of paxillin-containing adhesions. Both cofilin-1 and destrin silencing enhanced cell adhesion to extracellular matrix components. However, only destrin appeared to be required for cell migration on collagen I and for cell invasion through Matrigel in response to the proinvasive neuroendocrine peptide bombesin. This differential functional involvement was supported by a destrin-dependent, cofilin-independent phosphorylation of p130Crk-associated substrate (p130Cas) upon cell adhesion to collagen I or Matrigel. Taken together, our results suggest that destrin is a significant regulator of various processes important for invasive phenotype of human colon cancer Isreco1 cells whereas cofilin-1 may be involved in only a subset of them.

The role of angiogenesis in endocrine liver metastases: an experimental study

Liver metastases are a major adverse event during the evolution of digestive endocrine tumors. However, little is known about their natural history and the determinants of their growth. In particular, whereas liver endocrine metastases, like their primary counterparts, are hypervascular, the role of tumor-associated angiogenesis has been little explored. We therefore designed an experimental model to study the intrahepatic growth of tumor endocrine cells; murine enteroendocrine STC-1 cells were injected into the spleen of nude mice to obtain their hepatic dissemination through the portal vein. Three stages of intrahepatic tumor growth were identified. Engraftment stage, until day 4 after intrasplenic injection of STC-1 cells, was avascular. Early growth, until day 17, resulted in small, infralobular nodules. Late growth, after day 17, was characterized by the development of large nodules associated with peritumoral vessels and containing abnormal intratumoral vessels. To test the effects of potentially anti-angiogenic agents on tumor growth, we then used STC-1 cells stably transfected with the endostatin-coding sequence. Intrahepatic tumor volume showed no significant change at days 4 and 8, but a dramatic decrease at day 28 (9.7 +/- 1.7% of liver tissue versus 25.2 +/- 2.4% in controls), because of a markedly lower number of large nodules (11 +/- 1.8% versus 42 +/- 5.8%) likely to result from an increased apoptotic index (39.4 +/- 5.6% versus 18.3 +/- 3.4). Our results suggest that active angiogenesis is not necessary for the engraftment and early growth of endocrine cells metastatic to the liver but is required at a later stage of progression.

The role of fibroblasts in the modulation of integrin-dependent interactions between the gastric cell line HGT-1 and fibronectin

Fibronectin plays an important role in gastric cancer progression. However, little is known about the microenvironmental factors modulating integrin-dependent interactions between gastric cancer cells and fibronectin. We therefore studied the regulation by fibroblasts of the integrin-dependent adhesion and migration of the gastric cancer cell line HGT-1 onto fibronectin. We first determined, by immunofluorescence, immunoblotting and flow cytometry, that HGT-1 cells expressed alpha3, alpha5, alpha6, alphaV and beta1 integrin chains, and the alphaVbeta3 and alphaVbeta5 dimers. We verified that HGT-1 cells xenografted to the immunosuppressed newborn rat retained the integrin repertoire detected in vitro and were able to induce the formation of tumors rich in fibronectin. By using an in vitro assay in the presence of neutralizing antibodies, we verified that HGT-1 adhesion and migration onto fibronectin involved beta1, alphaV and alpha5 integrin chains; we verified, by using an in situ adhesion test to rat gastric wall frozen sections, that in situ HGT-1 adhesion to fibronectin was integrin dependent. In coculture experiments, we showed that organ-specific fibroblasts from stomach, lung and dermis were able to induce, in a site-specific manner, the expression of beta1, alpha5 and alphaV integrin chains in HGT-1 cells, their integrin-dependent adhesion and migration on fibronectin and their capacity to secrete oncofetal fibronectin. In conclusion, our results show the capacity for tissue-derived fibroblasts to modulate the integrin-dependent interactions between the gastric cell line HGT-1 and fibronectin. They strongly suggest that, in gastric cancer, stromal fibroblasts contribute to promote fibronectin-mediated local invasion by tumor cells.

Inhibition of proprotein convertases enhances cell migration and metastases development of human colon carcinoma cells in a rat model

Although proprotein convertases are involved in tumor development, nothing is known about their role in metastatic dissemination. To investigate the involvement of convertase inhibition, we used human colon carcinoma cells overexpressing alpha1-antitrypsin Portland (alpha1-PDX, PDX39P cells), a potent convertase inhibitor. We previously reported that these cells bear uncleaved integrin alpha subunits and display an altered attachment to vitronectin that is correlated with defects in the intracellular signaling pathways activated by alphavbeta5 integrin ligation. In this study, we demonstrate that the inhibition of proprotein convertase activity either by overexpression of alpha1-PDX or with the synthetic inhibitor decanoyl-Arg-Val-Lys-Arg-chloromethylketone (dec-RVKR-cmk) led to a significant increase in cell migration supported by the alphavbeta5 integrin. A collagen gel invasion assay showed that PDX39P cells also displayed an invasive ability, contrary to control cells. Moreover, when injected to immunosuppressed newborn rats, PDX39P cells were highly invasive, as they induce 10 times more metastases than mock-transfected cells. In addition, the aggressiveness of PDX39P cells can be greatly reduced by a function-blocking monoclonal antibody (mAb) against the alphav subunit. It thus seems that inhibition of proprotein convertases enhances the in vivo invasiveness of colon tumor cells likely due to an increase in cell migration mediated by alphav integrins.

The endoproteolytic processing of alphavbeta5 integrin is involved in cytoskeleton remodelling and cell migration

We previously showed that the post-translational cleavage of alphav subunit is essential for integrin-dependent signalling and cell adhesion. Here, we report that blocking alphav subunit cleavage by expression of alpha1-PDX, a convertase inhibitor, modified the capacity of cells to change shape, via a remodelling of the actin cytoskeleton upon cell attachment. These changes are associated with cell scattering and with a dramatic increase in cell migration to vitronectin. The alphav subunit cleavage is thus essential for integrin function and has a considerable impact on integrin-dependent events, especially those leading to cell migration.

Age-dependent variations of human and rat colon myofibroblasts in culture: Influence on their functional interactions with colon cancer cells

Epithelial-mesenchymal interactions play a pivotal role in colon cancer invasion and metastasis. We aimed at elucidating the impact of long-term cultivation on the phenotypic and functional characteristics of primary fibroblasts and their interaction with the human colon adenocarcinoma cell line LoVoC5. We used fibroblasts from human colon tumor tissue, normal human colon mucosa, rat normal colon and 2 rat colon-derived myofibroblast cell lines, MIC316 and MG. The following parameters were studied: cell shape and size, growth curve, intermediate filament expression and extracellular matrix synthesis. Coculture models with or without cell contacts were used to test the effects on LoVoC5 cell proliferation, spreading and adhesion. Irrespective of their origin, fibroblastic cells in primary cultures presented marked phenotypic and functional changes with time. Before passage 5, they presented as large, slow-growing cells expressing vimentin and alpha-smooth muscle actin; synthesizing laminin-1, fibronectin and collagens I and IV; and inducing LoVoC5 proliferation, spreading and adhesion. After passage 15, they presented as small, fast-growing cells inconstantly expressing alpha-smooth muscle actin and synthesizing mainly type I collagen. In coculture with or without cell contacts, they inhibited LoVoC5 proliferation and allowed only limited cell spreading and adhesion. Myofibroblastic cell lines presented as large, fast-growing cells expressing vimentin and alpha-smooth muscle actin and synthesizing mainly type I collagen. They had no significant effects on LoVoC5 proliferation, spreading and adhesion. Our results underline the importance of age-dependent variations in colon mesenchymal cells in culture and for the in vitro study of epithelial-mesenchymal interactions in colon cancer.

Relationship between vascular development and vascular differentiation during liver organogenesis in humans

BACKGROUNDS/AIMS

The complex vascular architecture characteristic of the normal adult liver is progressively acquired during the fetal life. In this study, we aimed to evaluate the relationship between angiogenesis and vascular differentiation during liver organogenesis.

METHODS

We studied, in 51 fetuses of different gestational ages, the expression of markers of endothelial cell differentiation, integrins, pro- and anti-angiogenic extracellular matrix components, vascular endothelial growth factor (VEGF) and its receptors.

RESULTS

Three main stages in the development of the vascular architecture of the liver were identified: (a) from 5 to 10 gestation weeks (GW), no evidence of de novo angiogenesis was detected; the vessels present in the liver primordium were the precursors of portal veins and sinusoids, deriving from preexisting vessels; (b) from 10 to 25 GW, angiogenesis and vasculogenesis resulted in the development of, respectively, arteries and intra-portal capillaries, while portal veins and hepatic sinusoids followed a differentiation process; (c) after 25 GW, little changes were detected in the various vascular compartments. The maximal expression of VEGF and its receptors was from 5 to 25 GW.

CONCLUSIONS

The development of the hepatic vascular architecture is a multistep process combining angiogenesis, vasculogenesis and vascular differentiation, regulated by specific growth and differentiation factors including VEGF.

Expression, regulation, and function of alpha V integrins in hepatocellular carcinoma: an in vivo and in vitro study

The expression of alpha V integrins by neoplastic cells contributes to the promotion of local invasion and metastasis. The most characteristic extracellular ligands of alpha V integrins are vitronectin and fibronectin. Hepatocytes are the main source of vitronectin, and the capacity to synthesize and secrete vitronectin is usually retained in hepatocellular carcinoma. The aim of this study was to explore the expression, regulation, and functional role of alpha V integrins in hepatocellular carcinoma. We first analyzed the expression of alpha V integrins and their ligands fibronectin and vitronectin in 80 cases of hepatocellular carcinoma. alpha V integrin chain was detected in 44 cases and vitronectin in 50. Twenty-four of the 44 alpha V-positive tumors contained large amounts of vitronectin. These cases presented more frequently with adverse histoprognostic factors, including infiltrative growth pattern (62.5%), lack of capsule (71%), presence of capsular invasion (57%), and satellite nodules (50%). We then used HepG2 and Hep3B cell lines as in vitro models to study alpha V integrin regulation and function. HepG2 and Hep3B cells expressed alpha V integrin chain and used alpha V beta 1 and alpha V beta 5 for adhesion and migration on vitronectin. Tumor necrosis factor (TNF) alpha and transforming growth factor (TGF) beta significantly increased the expression levels of alpha V integrins and stimulated the adhesion and migration of both HepG2 and Hep3B cell lines on vitronectin. The effects of growth factors on cell adhesion and migration were reproduced by incubation with conditioned medium from rat liver myofibroblasts. In conclusion, our results support the existence of an alpha V integrin/vitronectin connection in hepatocellular carcinoma and suggest that this connection may be an adverse prognostic factor.

Blocking a novel 55 kDa melanoma-associated cell surface antigen inhibits the development of spontaneous metastases and interactions with frozen lung section

We recently identified a novel 55-kDa cell-cell adhesion protein (p55) whose expression is upregulated in primary melanomas in the transition from radial growth phase to vertical growth phase. However, the functional role of p55 in various steps of the metastatic process had not been investigated. We provide evidence that subcutaneous injection of metastatic melanoma variant T1P26 in immunosuppressed newborn rats rapidly caused spontaneous metastatic lung lesions that could be readily detected by histochemical analysis with the anti-p55 monoclonal antibody (MAb) LY1. Subsequently, we were able to demonstrate that multiple subcutaneous injections of the LY1 MAb starting on the same day after tumor cell inoculation of T1P26 cells specifically blocked the formation of spontaneous lung metastases, yet had no effects on primary tumor growth, suggesting a critical role of p55 in the earlier steps of the intravasation process. To study later stages in spontaneous metastasis, we investigated the role of p55 in organ-specific cell adhesion of tumor cells in vitro. We showed that the T1P26 variant attached preferentially to lung frozen sections compared with other organs, reflecting the pattern of organ involvement of metastasis in vivo and that LY1 significantly blocked this interaction. However, no significant differences in attachment to lung sections were observed between the parental melanoma cell line M(4)Beu and its derived variant, although cellular topography analysis indicated a preferential attachment of a T1P26 variant on specific compartments of the lungs such as the perialveolar components, the endothelium and the vessel lumen of pulmonary venules. Attachment of the T1P26 variant to lung sections is not due to alterations of tumor cell adherence to basement membrane matrix by the LY1 MAb, suggesting that p55 is involved in cellular adhesion with cellular elements of the lung. p55 could represent a new functional constituent that contributes to the metastatic spread of melanoma cells by promoting the intravasation process and subsequent specific interactions between tumor cells and the target lung organ.

Integrin up-regulation in chronic liver disease: relationship with inflammation and fibrosis in chronic hepatitis C

In 94 patients with chronic hepatitis C, the pattern of integrin expression was correlated with firstly, the histological activity index, necro-inflammatory grade, and stage of fibrosis; secondly, the expression of inflammatory markers including ICAM-1; and thirdly, the extent and intensity of laminin deposition in the perisinusoidal matrix. Immunohistochemical results were evaluated according to a semi-quantitative scoring system or by image analysis. Increased beta1 expression was observed in 88.2% of cases. The expression of alpha1 and alpha5 was increased in 55% and 58.5% of cases, respectively. alpha6 chain was detected in 78.7% of cases. There were no statistically significant differences in integrin expression level according to Knodell's score, inflammatory grade, or stage of fibrosis. ICAM-1 expression was higher in patients with high scores for beta1 expression, but the differences were not statistically significant. There were significantly more patients with high scores for beta1 expression among those with continuous perisinusoidal deposition of laminin. Moreover, a close statistical correlation was observed between alpha6 induction and perisinusoidal laminin deposition (p<0.001). The results suggest that integrin up-regulation in chronic hepatitis C is more closely related to the fibrotic process than to the inflammatory lesions. This reinforces the idea that integrin induction in chronic liver disease is part of a coordinated process involved in the progression of liver fibrosis.

Lack of antitumor activity of recombinant endostatin in a human neuroblastoma xenograft model

Patients with metastatic neuroblastoma are rarely curable with currently available therapy, and the search for new treatment options, which include the use of inhibitors of tumor angiogenesis, is warranted. Here, we have evaluated the efficacy of one of the most promising natural inhibitors of angiogenesis described to date, endostatin, in a human neuroblastoma xenograft model in nude mice. Murine endostatin cDNA was cloned in a bacterial expression vector, expressed as a polyHis-Endostatin fusion protein and purified on Ni2+-NTA beads. The in vitro activity of soluble endostatin was confirmed on bovine capillary endothelial cells and human umbilical vein endothelial cells. The human neuroblastoma cell line SKNAS was injected subcutaneously in the flank of nude mice and administration of the recombinant angiogenesis inhibitor started when tumors reached the size of 100 microm3. Twenty mg/kg of recombinant precipitated endostatin or PBS was subcutaneously injected daily for 12 days. Serum endostatin levels were measured using a competitive enzyme immunoassay. Tumor growth was only slowed down in endostatin-treated mice when compared to control mice, and no statistically significant difference in serum levels of endostatin was observed between endostatin-treated and control groups. The lack of correlation between serum concentration and tumor response raises concern regarding the mechanism of action of endostatin.

Endothelial cell marker expression in dysplastic lesions of the liver: an immunohistochemical study

BACKGROUNDS/AIMS

Hepatocellular carcinoma usually contains continuous capillary vessels lacking the differentiation markers specific for normal sinusoidal endothelial cells. We therefore aimed to search for alterations in endothelial cell marker expression in precancerous liver lesions.

METHODS

Expression of the endothelial cell markers CD31, CD34 and BNH9 was analyzed in 138 dysplastic lesions from 40 cirrhotic patients (20 with and 20 without hepatocellular carcinoma).

RESULTS

No expression of the three endothelial cell markers was detected in cirrhotic nodules and in non dysplastic regenerative macronodules. The three markers were detected in 29.8% of dysplastic lesions and 47% of hepatocellular carcinomas. At least one marker was detected in 75% of dysplastic lesions and 100% of hepatocellular carcinomas. The three markers were more frequently expressed in areas of small cell than of large cell change (34 vs 10%). No correlation was found with the grade of dysplasia, the occurrence of arterialization and the association with hepatocellular carcinoma.

CONCLUSIONS

Alterations in the hepatic microcirculation comparable to those observed in hepatocellular carcinoma are present in a significant proportion of dysplastic lesions of the liver and may be indirect markers of the process of liver carcinogenesis.

Distribution of alphavbeta3, alphavbeta5 integrins and the integrin associated protein--IAP (CD47) in human glomerular diseases

The alphav integrins present on the membrane of numerous cells, mediate attachment to matrix proteins, cell proliferation, migration and survival. We studied the expression of alphav integrinis and CD47 (a beta3 chain integrin associated protein) in various forms of glomerulonephritis (GN) characterized by mesangial proliferation and/or increased mesangial matrix. In normal glomeruli, epithelial cells expressed alphavbeta3, alphavbeta5 and CD47; endothelial cells expressed alpha5beta1 and CD47; mesangial cells expressed alphavbeta5, CD47, and to a less extent alphavbeta3. In acute post infectious GN (APIGN), membrano-proliferative GN (MPGN) and diabetic nephropathy(DN), we observed that the beta3 chain, normally expressed by mesangial cells, was not detectable in the mesangium while its expression by epithelial cells was not modified. Parallel to the disappearance of alphavbeta3, the CD47 expression was decreased on the mesangial cells in MPGN, APIGN and DN. The expression of alphavbeta5 was clearly increased on podocytes and on proliferating mesangial cells in APIGN. By contrast, the mesangial expression of alphavbeta was normal or decreased in DN. The alpha5 chain of integrin, absent on normal mesangial cell, was expressed on proliferating mesangial cells in MPGN and APIGN. Thus, we observed modifications of alphavbeta3 and alphavbeta5 expression during human GN. The modulations of alphavbeta3 and alphavbeta5 expression differed according to the different glomerular cell types and were not parallel in glomerular cells: alphavbeta3 was decreased (and alphavbeta5 unchanged) on proliferating mesangial cells and alphavbeta5 was increased (and alphavbeta3 unchanged) in podocytes. This may reflect the existence of two distinct regulatory pathways.

[Effects of endocrine peptides on proliferation, migration and differentiation of human endothelial cells]

AIMS

We aimed to evaluate the effects of several peptides (substance P, VIP, neuropeptide Y, bombesin, glucagon and somatostatin) on the proliferation, migration and differentiation of human endothelial cells and their modulation by an anti-angiogenic factor, endostatin.

METHODS

Human endothelial cells (HUVEC) were isolated from umbilical veins. Their proliferation was measured by the incorporation of tritiated thymidine. Their migration was evaluated by using an haptotactic assay performed in Boyden chambers, after metabolic labeling of HUVEC through (35) S-methionin. Differentiation was evaluated as the capacity for HUVEC to form capillaries.

RESULTS

Endothelial cell proliferation was increased by neuropeptide Y, bombesin and glucagon. Somatostatin induced a significant decrease in basal and stimulated endothelial cell proliferation. The migration of HUVEC increased in the presence of substance P, VIP, neuropeptide Y, bombesin, glucagon and somatostatin. The number of capillaries was increased by substance P and VIP and decreased by neuropeptide Y, bombesin and somatostatin. Endostatin induced a significant decrease in endothelial cell proliferation in the basal state and after stimulation by neuropeptide Y and bombesin. Endostatin had no additive effect on the anti-proliferative action of somatostatin.

CONCLUSIONS

Our results suggest a role for endocrine peptides in the regulation of tumor angiogenesis. The potent anti-angiogenic effect of somatostatin may promote new therapeutic strategies.

alpha6beta1 integrin expression in hepatocarcinoma cells: regulation and role in cell adhesion and migration

Liver carcinogenesis is associated with striking changes in the integrin repertoire of hepatocytes, including the overexpression of the laminin and collagen receptors alpha1beta1 and the de novo induction of the laminin receptor alpha6beta1. Our aim was to analyze the role of pro-inflammatory cytokines, interferons and fibrogenic cytokines TGF-beta and FGF2 in the regulation of the expression of beta1 integrins by neoplastic hepatocytes. The 2 human hepatocellular cell lines HepG2 and Hep3B were used as models. Integrin expression was assessed by qualitative methods (immunocytochemistry, Western blotting) and semi-quantitative techniques (FACS, cellular ELISA), before and after stimulation by TNFalpha, IL1-beta, TGF-beta, FGF2, interferon gamma and interferon alpha-2b. HepG2 and Hep3B constitutively expressed alpha1, alpha2, alpha6 and beta1 chains. A 24 to 48-hr stimulation with pro-inflammatory cytokines, TGF-beta and FGF2 induced a significant increase in the concentrations of all integrin chains. The maximum induction was registered for beta1 chain, which presented increases amounting up to 3, 4 and 7 times the control values in the presence of, respectively, TNF alpha/IL1-beta, TGF-beta and FGF2. Interferons had no direct effect on integrin expression and partially antagonized the effects of TNF alpha and TGF-beta. The increased concentrations of integrin chains were associated with an increased membrane expression of the corresponding dimers and with an increased adhesion of stimulated hepatocytes to laminin, which was antagonized by neutralizing anti-beta1 and anti-alpha6 antibodies. Finally, anti-alpha6 antibody inhibited the migration of HepG2 and Hep3B cells in reconstituted basement membrane. Our results suggest that the stimulation of alpha6beta1 integrin expression in hepatocarcinoma cells is essential for cell adhesion and migration.

alpha6beta1 integrin expression in hepatocarcinoma cells: regulation and role in cell adhesion and migration

Liver carcinogenesis is associated with striking changes in the integrin repertoire of hepatocytes, including the overexpression of the laminin and collagen receptors alpha1beta1 and the de novo induction of the laminin receptor alpha6beta1. Our aim was to analyze the role of pro-inflammatory cytokines, interferons and fibrogenic cytokines TGF-beta and FGF2 in the regulation of the expression of beta1 integrins by neoplastic hepatocytes. The 2 human hepatocellular cell lines HepG2 and Hep3B were used as models. Integrin expression was assessed by qualitative methods (immunocytochemistry, Western blotting) and semi-quantitative techniques (FACS, cellular ELISA), before and after stimulation by TNFalpha, IL1-beta, TGF-beta, FGF2, interferon gamma and interferon alpha-2b. HepG2 and Hep3B constitutively expressed alpha1, alpha2, alpha6 and beta1 chains. A 24 to 48-hr stimulation with pro-inflammatory cytokines, TGF-beta and FGF2 induced a significant increase in the concentrations of all integrin chains. The maximum induction was registered for beta1 chain, which presented increases amounting up to 3, 4 and 7 times the control values in the presence of, respectively, TNF alpha/IL1-beta, TGF-beta and FGF2. Interferons had no direct effect on integrin expression and partially antagonized the effects of TNF alpha and TGF-beta. The increased concentrations of integrin chains were associated with an increased membrane expression of the corresponding dimers and with an increased adhesion of stimulated hepatocytes to laminin, which was antagonized by neutralizing anti-beta1 and anti-alpha6 antibodies. Finally, anti-alpha6 antibody inhibited the migration of HepG2 and Hep3B cells in reconstituted basement membrane. Our results suggest that the stimulation of alpha6beta1 integrin expression in hepatocarcinoma cells is essential for cell adhesion and migration.

Expression of integrins during liver organogenesis in humans

Integrins play a pivotal role in organogenesis, by mediating the interactions between differentiating cells and the extracellular matrix. We analyzed the expression of integrins and their ligands during human liver organogenesis. The expression of beta1, beta3, and beta4 integrins and the distribution of several extracellular matrix proteins were studied by immunoperoxidase in fetal liver samples from 5 to 40 weeks' gestation. Hepatoblasts expressed only the beta1, alpha1, alpha5, alpha6, and alpha9 integrin chains. Fetal hepatocytes, emerging at the 8th week of gestation, initially retained the same combination of integrins, but presented a progressive decrease in their expression levels. After 15 weeks' gestation, the expression levels of beta1, alpha1, alpha5, and alpha9 reached levels comparable to those observed in the adult state. Alpha6 expression became undetectable after 30 weeks' gestation. As compared to hepatoblasts, intrahepatic biliary epithelial cells, differentiating at the 8th week of gestation in the ductal plate, were characterized by the progressive loss of alpha1, the marked induction of alpha6, and the de novo acquisition of the beta4, alpha2, and alpha3 integrin chains. The disappearance of integrin receptors for laminin on hepatocytes was associated with the rarefaction of laminin in the perisinusoidal matrix, whereas their induction on biliary epithelial cells was associated with laminin deposition at the point of contact with the ductal plate. In conclusion, integrins likely play an important role in the differentiation of the epithelial and endothelial cell populations of the liver.