The role of extracellular matrix components in angiogenesis and fibrosis: Possible implication for Systemic Sclerosis

Identification of atrial fibrillation-related genes through transcriptome data analysis and Mendelian randomization

Background

Atrial fibrillation (AF) is a common persistent arrhythmia characterized by rapid and chaotic atrial electrical activity, potentially leading to severe complications such as thromboembolism, heart failure, and stroke, significantly affecting patient quality of life and safety. As the global population ages, the prevalence of AF is on the rise, placing considerable strains on individuals and healthcare systems. This study utilizes bioinformatics and Mendelian Randomization (MR) to analyze transcriptome data and genome-wide association study (GWAS) summary statistics, aiming to identify biomarkers causally associated with AF and explore their potential pathogenic pathways.

Methods

We obtained AF microarray datasets GSE41177 and GSE79768 from the Gene Expression Omnibus (GEO) database, merged them, and corrected for batch effects to pinpoint differentially expressed genes (DEGs). We gathered exposure data from expression quantitative trait loci (eQTL) and outcome data from AF GWAS through the IEU Open GWAS database. We employed inverse variance weighting (IVW), MR-Egger, weighted median, and weighted model approaches for MR analysis to assess exposure-outcome causality. IVW was the primary method, supplemented by other techniques. The robustness of our results was evaluated using Cochran's Q test, MR-Egger intercept, MR-PRESSO, and leave-one-out sensitivity analysis. A "Veen" diagram visualized the overlap of DEGs with significant eQTL genes from MR analysis, referred to as common genes (CGs). Additional analyses, including Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and immune cell infiltration studies, were conducted on these intersecting genes to reveal their roles in AF pathogenesis.

Results

The combined dataset revealed 355 differentially expressed genes (DEGs), with 228 showing significant upregulation and 127 downregulated. Mendelian randomization (MR) analysis identified that the autocrine motility factor receptor (AMFR) [IVW: OR = 0.977; 95% CI, 0.956-0.998; P = 0.030], leucine aminopeptidase 3 (LAP3) [IVW: OR = 0.967; 95% CI, 0.934-0.997; P = 0.048], Rab acceptor 1 (RABAC1) [IVW: OR = 0.928; 95% CI, 0.875-0.985; P = 0.015], and tryptase beta 2 (TPSB2) [IVW: OR = 0.971; 95% CI, 0.943-0.999; P = 0.049] are associated with a reduced risk of atrial fibrillation (AF). Conversely, GTPase-activating SH3 domain-binding protein 2 (G3BP2) [IVW: OR = 1.030; 95% CI, 1.004-1.056; P = 0.024], integrin subunit beta 2 (ITGB2) [IVW: OR = 1.050; 95% CI, 1.017-1.084; P = 0.003], glutaminyl-peptide cyclotransferase (QPCT) [IVW: OR = 1.080; 95% CI, 1.010-0.997; P = 1.154], and tripartite motif containing 22 (TRIM22) [IVW: OR = 1.048; 95% CI, 1.003-1.095; P = 0.035] are positively associated with AF risk. Sensitivity analyses indicated a lack of heterogeneity or horizontal pleiotropy (P > 0.05), and leave-one-out analysis did not reveal any single nucleotide polymorphisms (SNPs) impacting the MR results significantly. GO and KEGG analyses showed that CG is involved in processes such as protein polyubiquitination, neutrophil degranulation, specific and tertiary granule formation, protein-macromolecule adaptor activity, molecular adaptor activity, and the SREBP signaling pathway, all significantly enriched. The analysis of immune cell infiltration demonstrated associations of CG with various immune cells, including plasma cells, CD8T cells, resting memory CD4T cells, regulatory T cells (Tregs), gamma delta T cells, activated NK cells, activated mast cells, and neutrophils.

Conclusion

By integrating bioinformatics and MR approaches, genes such as AMFR, G3BP2, ITGB2, LAP3, QPCT, RABAC1, TPSB2, and TRIM22 are identified as causally linked to AF, enhancing our understanding of its molecular foundations. This strategy may facilitate the development of more precise biomarkers and therapeutic targets for AF diagnosis and treatment.

Solid Lipid Nanoparticles Encapsulating a Benzoxanthene Derivative in a Model of the Human Blood-Brain Barrier: Modulation of Angiogenic Parameters and Inflammation in Vascular Endothelial Growth Factor-Stimulated Angiogenesis

Lignans, a class of secondary metabolites found in plants, along with their derivatives, exhibit diverse pharmacological activities, including antioxidant, antimicrobial, anti-inflammatory, and antiangiogenic ones. Angiogenesis, the formation of new blood vessels from pre-existing ones, is a crucial process for cancer growth and development. Several studies have elucidated the synergistic relationship between angiogenesis and inflammation in various inflammatory diseases, highlighting a correlation between inflammation and vascular endothelial growth factor (VEGF)-induced angiogenesis. Thus, the identification of novel molecules capable of modulating VEGF effects presents promising prospects for developing therapies aimed at stabilizing, reversing, or even arresting disease progression. Lignans often suffer from low aqueous solubility and, for their use, encapsulation in a delivery system is needed. In this research, a bioinspired benzoxantene has been encapsulated in solid lipid nanoparticles that have been characterized for their pharmacotechnical properties and their thermotropic behavior. The effects of these encapsulated nanoparticles on angiogenic parameters and inflammation in VEGF-induced angiogenesis were evaluated using human brain microvascular endothelial cells (HBMECs) as a human blood-brain barrier model.

Transcriptomic characterization of lung pericytes in systemic sclerosis-associated pulmonary fibrosis

Systemic sclerosis (SSc) is a chronic disease characterized by fibrosis and vascular abnormalities in the skin and internal organs, including the lung. SSc-associated pulmonary fibrosis (SSc-PF) is the leading cause of death in SSc patients. Pericytes are key regulators of vascular integrity and endothelial function. The role that pericytes play in SSc-PF remains unclear. We compared the transcriptome of pericytes from SSc-PF lungs (SScL) to pericytes from normal lungs (NORML). We identified 1,179 differentially expressed genes in SScL pericytes. Pathways enriched in SScL pericytes included prostaglandin, PI3K-AKT, calcium, and vascular remodeling signaling. Decreased cyclic AMP production and altered phosphorylation of AKT in response to prostaglandin E2 in SScL pericytes demonstrate the functional consequence of changes in the prostaglandin pathway that may contribute to fibrosis. The transcriptomic signature of SSc lung pericytes suggests that they promote vascular dysfunction and contribute to the loss of protection against lung inflammation and fibrosis.

Serum endocan levels in children with rheumatic aortic insufficiency: can it differentiate bicuspid aortic valve disease from rheumatic heart disease?

AIM

In this study, it was aimed to examine the serum endocan levels in patients with rheumatic aortic regurgitation and to investigate whether it has a value in differentiating it from aortic regurgitation due to bicuspid aortic valve.

METHODS

Blood samples were collected from patients with rheumatic aortic regurgitation (Group 1), incidentally diagnosed patients with borderline or definite rheumatic aortic regurgitation (Group 2), children with bicuspid aortic valve accompanied by aortic regurgitation (Group 3) and healthy children (Group 4) of similar age.

RESULTS

There were 12 children in Group 1, 13 in Group 2, 25 in Group 3, and 25 in Group 4. Groups were similar in terms of age (p = 0.291). There was no statistically significant difference between median serum endocan levels of Group 1 and Group 2 (p = 0.624), and Group 3 and Group 4 (p = 0.443). Despite that, the median serum endocan levels of Group 1 and Group 2 were significantly higher than that of both Group 3 and Group 4 (p = 0.000 for all).

CONCLUSIONS

Our results indicate that serum endocan level can be used to differentiate rheumatic aortic regurgitation from non-rheumatic aortic regurgitation. It is thought that the prognostic role of this marker should be confirmed in long-term, prospective studies with larger samples.

αvβ3 Integrin as a Link between the Development of Fibrosis and Thyroid Hormones in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of the skin and internal organs. Key players mediating fibrosis are myofibroblasts (MF) that, following transforming growth factor β (TGFβ) exposure, produce a collagen-rich extracellular matrix (ECM) that induces myofibroblast differentiation. Myofibroblasts express αvβ3 integrin (a membrane receptor for thyroid hormones) and miRNA-21 that promotes deiodinase-type-3 expression (D3), causing the degradation of triiodothyronine (T3) that attenuates fibrosis. We hypothesized that αvβ3 affects the fibrotic processes through its thyroid hormones (THs) binding site. To test this, dermal fibroblasts (DF) were cultured with/without TGFβ and removed with a base, leaving only normal/fibrotic ECMs in wells. Then, DF were cultured on the ECMs with/without tetrac (αvβ3 ligand, T4 antagonist), and evaluated for pro-fibrotic characteristics, αvβ3, miRNA-21, and D3 levels. Blood free-T3 (fT3), miRNA-21 levels, and the modified Rodnan skin score (MRSS) were evaluated in SSc patients. We found that the "fibrotic-ECM" significantly increased the pro-fibrotic characteristics of DF and the levels of miRNA-21, D3, and αvβ3, compared to the "normal-ECM." Tetrac significantly inhibited the effects of the "fibrotic-ECM" on the cells. In accordance with tetrac's effect on D3/miRNA-21, a negative correlation was found between the patients' fT3 to miRNA-21 levels, and to the development of pulmonary arterial hypertension (PAH). We conclude that occupying the THs binding site of αvβ3 may delay the development of fibrosis.

Angiogenic signaling pathways and anti-angiogenic therapy for cancer

Angiogenesis, the formation of new blood vessels, is a complex and dynamic process regulated by various pro- and anti-angiogenic molecules, which plays a crucial role in tumor growth, invasion, and metastasis. With the advances in molecular and cellular biology, various biomolecules such as growth factors, chemokines, and adhesion factors involved in tumor angiogenesis has gradually been elucidated. Targeted therapeutic research based on these molecules has driven anti-angiogenic treatment to become a promising strategy in anti-tumor therapy. The most widely used anti-angiogenic agents include monoclonal antibodies and tyrosine kinase inhibitors (TKIs) targeting vascular endothelial growth factor (VEGF) pathway. However, the clinical benefit of this modality has still been limited due to several defects such as adverse events, acquired drug resistance, tumor recurrence, and lack of validated biomarkers, which impel further research on mechanisms of tumor angiogenesis, the development of multiple drugs and the combination therapy to figure out how to improve the therapeutic efficacy. Here, we broadly summarize various signaling pathways in tumor angiogenesis and discuss the development and current challenges of anti-angiogenic therapy. We also propose several new promising approaches to improve anti-angiogenic efficacy and provide a perspective for the development and research of anti-angiogenic therapy.

Fibroblast expression of CD248 may contribute to exacerbation of microvascular damage during systemic sclerosis

OBJECTIVES

CD248 is a glycoprotein, highly expressed on pericytes and fibroblasts (FBs), that is implicated in the fibrotic process. During angiogenesis, CD248 can promote vessel regression, binding multimerin-2 (MMRN-2). Thus, we investigated the expression of MMRN-2 in systemic sclerosis (SSc)-skin and of CD248 in isolated SSc-FBs. The anti-angiogenic property of CD248+ SSc-FBs was evaluated by co-culturing these cells with healthy control endothelial cells (HC-ECs). The apoptotic effect of CD248 on HC-ECs was evaluated. Finally, the ability of CD248 to prevent activation of VEGF receptor 2 (VEGFR2) was assessed.

METHODS

By IF, MMRN-2 was investigated in SSc-skin and CD248 in SSc FBs. The anti-angiogenic property of CD248+ SSc-FBs was evaluated by HC-ECs/SSc-FBs co-cultures. Lentiviral-induced CD248 short-hairpin RNA delivery was employed for loss-of-function studies in SSc-FBs. HC-ECs were cultured in the presence of CD248 to assess apoptosis by IF and VEGFR2 phosphorylation by western blot.

RESULTS

MMRN-2 expression was increased in skin SSc-ECs, whereas CD248 expression was increased in SSc-FBs. Functionally, CD248+-SSc-FBs suppressed angiogenesis in the organotypic model, as assessed by the reduction in total tube length of HC-ECs. This anti-angiogenetic behaviour was reversed by CD248 silencing. Furthermore, the presence of CD248 promoted the apoptosis of HC-ECs. Finally, CD248 prevented activation of VEGFR2 by reducing its phosphorylation after VEGF stimulation.

CONCLUSION

CD248 was anti-angiogenic in vitro due to a reduction in tube formation and to induction of apoptosis of ECs. Increased expression of CD248 in SSc could contribute to the microvascular rarefaction observed at the tissue level in SSc. Our results suggest a pathogenic role for CD248-MMRN-2 in SSc.

Identification of lncRNA-miRNA-mRNA networks in circulating exosomes as potential biomarkers for systemic sclerosis

Objective

This study aimed to analyze potential biomarkers for systemic sclerosis (SSc) by constructing lncRNA-miRNA-mRNA networks in circulating exosomes (cirexos).

Materials and methods

Differentially expressed mRNAs (DEmRNAs) and lncRNAs (DElncRNAs) in SSc cirexos were screened using high-throughput sequencing and detected with real-time quantitative PCR (RT-qPCR). Differentially expressed genes (DEGs) were analyzed using the DisGeNET, GeneCards, GSEA4.2.3, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Receiver operating characteristic (ROC) curves, correlation analyses, and a double-luciferase reporter gene detection assay were used to analyze competing endogenous RNA (ceRNA) networks and clinical data.

Results

In this study, 286 DEmRNAs and 192 DElncRNAs were screened, of which 18 DEGs were the same as the SSc-related genes. The main SSc-related pathways included extracellular matrix (ECM) receptor interaction, local adhesion, platelet activation, and IgA production by the intestinal immune network. A hub gene, COL1A1, was obtained by a protein-protein interaction (PPI) network. Four ceRNA networks were predicted through Cytoscape. The relative expression levels of COL1A1, ENST0000313807, and NON-HSAT194388.1 were significantly higher in SSc, while the relative expression levels of hsa-miR-29a-3p, hsa-miR-29b-3p, and hsa-miR-29c-3p were significantly lower in SSc (P < 0.05). The ROC curve showed that the ENST00000313807-hsa-miR-29a-3p-COL1A1 network as a combined biomarker of SSc is more valuable than independent diagnosis, and that it is correlated with high-resolution CT (HRCT), Scl-70, C-reactive protein (CRP), Ro-52, IL-10, IgM, lymphocyte percentage, neutrophil percentage, albumin divided by globulin, urea, and RDW-SD (P < 0.05). Double-luciferase reporter gene detection showed that ENST00000313807 interacts with hsa-miR-29a-3p, which interacts with COL1A1.

Conclusion

The ENST00000313807-hsa-miR-29a-3p-COL1A1 network in plasma cirexos represents a potential combined biomarker for the clinical diagnosis and treatment of SSc.

Flow goes forward and cells step backward: endothelial migration

Systemic and pulmonary circulations constitute a complex organ that serves multiple important biological functions. Consequently, any pathological processing affecting the vasculature can have profound systemic ramifications. Endothelial and smooth muscle are the two principal cell types composing blood vessels. Critically, endothelial proliferation and migration are central to the formation and expansion of the vasculature both during embryonic development and in adult tissues. Endothelial populations are quite heterogeneous and are both vasculature type- and organ-specific. There are profound molecular, functional, and phenotypic differences between arterial, venular and capillary endothelial cells and endothelial cells in different organs. Given this endothelial cell population diversity, it has been challenging to determine the origin of endothelial cells responsible for the angiogenic expansion of the vasculature. Recent technical advances, such as precise cell fate mapping, time-lapse imaging, genome editing, and single-cell RNA sequencing, have shed new light on the role of venous endothelial cells in angiogenesis under both normal and pathological conditions. Emerging data indicate that venous endothelial cells are unique in their ability to serve as the primary source of endothelial cellular mass during both developmental and pathological angiogenesis. Here, we review recent studies that have improved our understanding of angiogenesis and suggest an updated model of this process.

Cells that line the inside of veins possess a unique ability to grow new blood vessels and a better understanding of these cells could lead to new treatments for cancer, autoimmunity and other diseases associated with abnormal blood vessel formation. Michael Simons and colleagues from Yale University School of Medicine in New Haven, USA, review the attributes of venous endothelial cells, such as their unique ability to proliferate and migrate against blood flow, and then to form new intricate networks of minute blood vessels, in response to appropriate signals. The authors discuss emerging evidence implicating these cells in a variety of diseases, and suggest that drugs aimed at modulating the molecular function or migratory activities of venous endothelial cells could be used to correct abnormal blood vessel expansion.

Cell-Seeded Biomaterial Scaffolds: The Urgent Need for Unanswered Accelerated Angiogenesis

One of the most arduous challenges in tissue engineering is neovascularization, without which there is a lack of nutrients delivered to a target tissue. Angiogenesis should be completed at an optimal density and within an appropriate period of time to prevent cell necrosis. Failure to meet this challenge brings about poor functionality for the tissue in comparison with the native tissue, extensively reducing cell viability. Prior studies devoted to angiogenesis have provided researchers with some biomaterial scaffolds and cell choices for angiogenesis. For example, while most current angiogenesis approaches require a variety of stimulatory factors ranging from biomechanical to biomolecular to cellular, some other promising stimulatory factors have been underdeveloped (such as electrical, topographical, and magnetic). When it comes to choosing biomaterial scaffolds in tissue engineering for angiogenesis, key traits rush to mind including biocompatibility, appropriate physical and mechanical properties (adhesion strength, shear stress, and malleability), as well as identifying the appropriate biomaterial in terms of stability and degradation profile, all of which may leave essential trace materials behind adversely influencing angiogenesis. Nevertheless, the selection of the best biomaterial and cells still remains an area of hot dispute as such previous studies have not sufficiently classified, integrated, or compared approaches. To address the aforementioned need, this review article summarizes a variety of natural and synthetic scaffolds including hydrogels that support angiogenesis. Furthermore, we review a variety of cell sources utilized for cell seeding and influential factors used for angiogenesis with a concentrated focus on biomechanical factors, with unique stimulatory factors. Lastly, we provide a bottom-to-up overview of angiogenic biomaterials and cell selection, highlighting parameters that need to be addressed in future studies.

Plasma endostatin correlates with hypoxia and mortality in COVID-19-associated acute respiratory failure

Background: The contribution of endothelial injury in the pathogenesis of COVID-19-associated acute respiratory distress syndrome (ARDS) and resulting respiratory failure remains unclear. Plasma endostatin, an endogenous inhibitor of angiogenesis and endothelial dysfunction is upregulated during hypoxia, inflammation and progress of pulmonary disease. Aim: To investigate if plasma endostatin is associated to hypoxia, inflammation and 30-day mortality in patients with severe COVID-19 infection. Method: Samples for blood analysis and plasma endostatin quantification were collected from adult patients with ongoing COVID-19 (n = 109) on admission to intensive care unit (day 1). Demographic characteristics and 30-day mortality data were extracted from medical records. The ability of endostatin to predict mortality was analyzed using receiving operating characteristics and Kaplan–Meier analysis with a cutoff at 46.2 ng/ml was used to analyze the association to survival. Results: Plasma endostatin levels correlated with; PaO₂/FiO2 (r = -0.3, p < 0.001), arterial oxygen tension (r = -0.2, p = 0.01), lactate (r = 0.2, p = 0.04), C-reactive protein (r = 0.2, p = 0.04), ferritin (r = 0.2, p = 0.09), D-dimer (r = 0.2, p = 0.08) and IL-6 (r = 0.4, p < 0.001). Nonsurvivors at 30 days had higher plasma endostatin levels than survivors (72 ± 26 vs 56 ± 16 ng/ml, p = 0.01). Receiving operating characteristic curve (area under the curve 0.7) showed that plasma endostatin >46.2 ng/ml predicts mortality with a sensitivity of 92% and specificity of 71%. In patients with plasma endostatin >46.2 ng/ml probability of survival was lower (p = 0.02) in comparison to those with endostatin <46.2 ng/ml. Conclusion: Our results suggest that plasma endostatin is an early biomarker for disease severity in COVID-19.

Expression and Pathogenic Analysis of Integrin Family Genes in Systemic Sclerosis

Objectives: Emerging evidence shows that integrin members are involved in inflammation and fibrosis in systemic sclerosis (SSc). This study aimed at evaluating the expression of integrin family genes in the skin tissue from SSc patients and exploring the potential pathogenic mechanism.

Methods: We utilized the public datasets of SSc skin tissue from the Gene Expression Omnibus (GEO) database to analyze the expression and clinical significance of integrin family genes in SSc. The expression of integrin members in skin tissue was also assessed by immunohistochemistry. In addition, functional enrichment and pathway analysis were conducted.

Results: Compared with healthy controls, the mRNA and protein levels of ITGA5, ITGB2, and ITGB5 were upregulated in the skin of SSc patients. Further analysis indicated that the mRNA expression levels of ITGA5, ITGB2, and ITGB5 were positively correlated with modified Rodnan skin thickness score (mRSS). Functional enrichment and pathway analysis showed that integrin members may play multiple roles in the pathogenesis of SSc. Among them, ITGA5, ITGB2, and ITGB5 might synergistically promote SSc through affecting extracellular matrix (ECM) turnover, ECM–receptor interaction, focal adhesion, and leukocyte trans-endothelial migration, while ITGA5 and ITGB5 also might affect angiogenesis and endothelial cell function. In addition, ITGA5, ITGB2, and ITGA5 were associated with different pathways, respectively. ITGA5 was uniquely enriched for actin organization, while ITGB5 was for TGF-β signaling and ITGB2 for immune cell activation.

Conclusion: Our results implied that the abnormal expression of integrin family genes including ITGA5, ITGB2, and ITGB5 may participate in multiple pathological processes in SSc. Further investigations are required for confirming this speculation.

Alterations of long non-coding RNA and mRNA profiles associated with extracellular matrix homeostasis and vascular aging in rats

Vascular aging has been closely associated with various cardiovascular disorders; however, its molecular mechanism remains poorly understood. In our study, RNA sequencing was utilized to explore the expression profiles of long non-coding RNAs (lncRNAs) and mRNAs in the thoracic aortas of young (3 weeks) and old (16 weeks) rats. Functional categorization of differentially expressed mRNAs was evaluated using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases, and lncRNA–microRNA–mRNA networks was constructed using Cytoscape software. In addition, three upregulated and three downregulated lncRNAs were further confirmed by quantitative reverse transcriptase-polymerase chain reaction. A total of 36 lncRNAs and 922 mRNAs were differential expression in the thoracic aortas of young and older rats. In addition, we found differentially expressed mRNAs that were enriched in multiple biological processes and signaling pathways associated with angiogenesis, such as extracellular matrix–receptor interaction and adenosine 3ʹ,5ʹ-monophosphate-activated protein kinase (AMPK) signaling. Moreover, AABR07013558.1, AABR07014823.1, and AABR07031489.1 were upregulated and ABR07053849.3, AABR07067310.2, and AC111292.1 were downregulated in the thoracic aortas of older rats compared with the young ones. Therefore, our findings provide several potential lncRNAs and mRNAs and signaling pathways related to vascular aging, which provide new clue for underlying the improvement of vascular aging.

[Expression of pituitary tumor-transforming gene-1 and its pathogenic role in systemic sclerosis]

OBJECTIVE

To investigate the expression of tumor-transforming gene-1 (PTTG1) in systemic sclerosis (SSc) and its role in fibrosis.

METHODS

Skin biopsy samples were collected from 21 patients with SSc and 22 patients with healthy skin for detecting the mRNA and protein expressions of PTTG1 using real-time PCR (RT-PCR) and immunohistochemistry, respectively. In cultured primary human dermal fibroblasts, PTTG1 expression was knocked down via RNA interference (siRNA), and the mRNA expression levels of PTTG1 and the fibrosis-related genes α-SMA, COL1A1, COL1A2, and COL3A1 were detected using RT-PCR; the proliferation of the cells was assessed using a real-time cell proliferation detection system.

RESULTS

Compared with those in normal skin samples, the mRNA and protein expressions of PTTG1 increased significantly in the skin tissue of patients with SSc (P < 0.05). In cultured primary skin fibroblasts, the expression of PTTG1 mRNA was positively correlated with those of α-SMA (R²=0.8192, P < 0.05), COL1A1 (R²=0.6398, P < 0.05), COL1A2 (R²=0.316, P < 0.05) and COL3A1 mRNAs (R²=0.3727, P < 0.05). Interference of PTTG1 expression significantly inhibited the cell proliferation, obviously lowered the expressions of fibrosis-related genes, and down-regulated the expression of collagen in the fibroblasts.

CONCLUSIONS

PTTG1 is highly expressed in skin tissues of patients with SSc, and PTTG1 knockdown can reduce the activity of the dermal fibroblasts, suggesting a close correlation of PTTG1 with fibrosis in SSc.

Progressive Reinvention or Destination Lost? Half a Century of Cardiovascular Tissue Engineering

The concept of tissue engineering evolved long before the phrase was forged, driven by the thromboembolic complications associated with the early total artificial heart programs of the 1960s. Yet more than half a century of dedicated research has not fulfilled the promise of successful broad clinical implementation. A historical account outlines reasons for this scientific impasse. For one, there was a disconnect between distinct eras each characterized by different clinical needs and different advocates. Initiated by the pioneers of cardiac surgery attempting to create neointimas on total artificial hearts, tissue engineering became fashionable when vascular surgeons pursued the endothelialisation of vascular grafts in the late 1970s. A decade later, it were cardiac surgeons again who strived to improve the longevity of tissue heart valves, and lastly, cardiologists entered the fray pursuing myocardial regeneration. Each of these disciplines and eras started with immense enthusiasm but were only remotely aware of the preceding efforts. Over the decades, the growing complexity of cellular and molecular biology as well as polymer sciences have led to surgeons gradually being replaced by scientists as the champions of tissue engineering. Together with a widening chasm between clinical purpose, human pathobiology and laboratory-based solutions, clinical implementation increasingly faded away as the singular endpoint of all strategies. Moreover, a loss of insight into the healing of cardiovascular prostheses in humans resulted in the acceptance of misleading animal models compromising the translation from laboratory to clinical reality. This was most evident in vascular graft healing, where the two main impediments to the in-situ generation of functional tissue in humans remained unheeded–the trans-anastomotic outgrowth stoppage of endothelium and the build-up of an impenetrable surface thrombus. To overcome this dead-lock, research focus needs to shift from a biologically possible tissue regeneration response to one that is feasible at the intended site and in the intended host environment of patients. Equipped with an impressive toolbox of modern biomaterials and deep insight into cues for facilitated healing, reconnecting to the “user needs” of patients would bring one of the most exciting concepts of cardiovascular medicine closer to clinical reality.

Autophagy mediates 2-methoxyestradiol-inhibited scleroderma collagen synthesis and endothelial-to-mesenchymal transition induced by hypoxia

OBJECTIVES

To investigate whether autophagy mediates 2-methoxyestradiol (2-ME)-inhibited hypoxia-induced fibrosis and endothelial-to-mesenchymal transition (endoMT) in SSc.

METHODS

Autophagy in the skin of SSc patients was assessed by transmission electron microscopy. SSc skin fibroblasts and human umbilical vein endothelial cells (HUVECs) were cultured under hypoxic (1% O2) conditions with 2-ME or autophagy inhibitor. Collagen I and connective tissue growth factor (CTGF) in fibroblasts and vascular endothelial (VE)-cadherin, CD31, vimentin and α-smooth muscle actin (α-SMA) in HUVECs were examined by western blotting. Autophagic markers were evaluated by confocal microscopy and immunofluorescence.

RESULTS

SSc skins presented increased autolysosomes, LC3-II, collagen I and CTGF. Hypoxia-challenged fibroblasts and HUVECs formed more autophagosomes and autolysosomes, with increased LC3 and decreased P62. Meanwhile, hypoxia increased collagen I and CTGF in fibroblasts and increased vimentin and α-SMA but decreased VE-cadherin and CD31 in HUVECs. Bafilomycin A1 increased LC3-II and P62 in fibroblasts and HUVECs and decreased collagen I and CTGF in fibroblasts and vimentin and α-SMA in HUVECs, while upregulating VE-cadherin and CD31. 3-methyladenine decreased autophagy and fibrosis in fibroblasts and endothelial-to-mesenchymal transition in HUVECs. 2-ME-treated HUVECs showed more autophagosomes and fewer autolysosomes while 2-ME-treated fibroblasts showed fewer of both. Moreover, 2-ME decreased LC3-II and increased P62 in fibroblasts and increased both in HUVECs. Inhibition of autophagy by 2-ME showed the same effect with bafilomycin A1 on fibroblast collagen synthesis as well as endothelial and mesenchymal markers in HUVECs.

CONCLUSION

Autophagy mediated hypoxia-induced fibroblast collagen synthesis and endoMT in SSc, which could be reversed by 2-ME.

Phase angle could be a marker of microvascular damage in systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is an autoimmune disease characterized by endothelial dysfunction with fibrosis of skin and internal organs. Integrity of the endothelial cell is important to its physiologic function such as production of angiogenetic factors. The aim of this study was to assess whether phase angle (PhA) is altered in patients with SSc and whether its values correlate with vascular endothelial growth factor (VEGF) and digital microvascular damage.

METHODS

Patients with SSc and matched healthy controls underwent VEGF determination and bioimpedentiometry (BIA) for PhA assessment. Clinical assessment, disease activity index (DAI), disease severity scale, and nailfold videocapillaroscopy (NCV) were performed in patients with SSc.

RESULTS

Fifty-five patients (46 women) with a mean age of 53.2 ± 13.7 y were studied. The mean value of VEGF was significantly higher in patients with SSc than in the healthy controls (240.3 ± 149.5 versus 139 ± 87.5; P = 0.035). The mean value of PhA was significantly lower in the patient grouop than in the healthy controls (4.51 ± 0.87 versus 5.22 ± 0.55; P < 0.0001). A significant positive correlation was found between VEGF and PhA (P = 0.009, beta coefficient = 1.48) in SSc patients. A negative correlation between VEGF and DAI (P = 0.048, β coefficient = 0.48) was found. PhA median value was significantly (P = 0.006) lower in patients with late pattern SSc (4.2 [2.5-5.3]). PhA median value was significantly (P < 0,0001) lower in patients with digital ulcers (DUs; 4.2 [2.5-5.3]) than in those without DUs (3.80 [2.50-5] versus 4.75 [2.80-7.3]). These data were confirmed in both female and male patients.

CONCLUSIONS

The evaluation of VEGF with PhA, NVC, and DUs could be useful to estimate cellular and microvascular damage in patients with SSc.

CCL20, a direct-acting pro-angiogenic chemokine induced by hepatitis C virus (HCV): Potential role in HCV-related liver cancer

The CCL20/CCR6 chemokine/receptor axis has previously been shown to contribute to the initiation and progression of hepatocellular carcinoma (HCC) through the recruitment of CCR6-positive leukocytes to the tumor microenvironment. In particular, high serum levels of CCL20 are reported in patients with HCC induced by the hepatitis C virus (HCV). A potential non-immune role for the CCL20/CCR6 axis in HCC development has not yet been investigated. Microarray analysis (Benkheil et al., paper submitted for publication), revealed that CCL20 is highly upregulated in hepatoma cells infected with HCV compared with non-infected hepatoma cells. To determine the role of the CCL20/CCR6 axis in HCV-related HCC, we first explored which cell populations express CCR6 in human liver tissue with chronic disease or HCC. Immunohistochemical (IHC) analysis revealed that CCR6 is present on endothelial cells (ECs) of portal blood vessels in livers with chronic HCV infection and in HCV- and alcoholic-HCC tissue. In addition, we found CCR6 to be expressed on primary macrovascular (HUVECs) and microvascular ECs (HMVEC-ds) where it co-expressed with the endothelial marker CD31. In vitro angiogenesis experiments revealed that CCL20 is a direct pro-angiogenic molecule that induces EC invasion, sprouting and migration through CCR6. Moreover, using the angiogenesis matrigel plug assay in immunodeficient NMRI-nu mice, we clearly showed that CCL20 induces blood vessel formation, by attracting CCR6-positive ECs. Finally, we demonstrated that HCV-induced CCL20 protein expression and secretion in hepatoma cells could be abolished by antiviral treatment, indicating that CCL20 expression is dependent on HCV replication. In contrast to HCV, HBV-infection resulted in a decreased expression of CCL20, implying a virus-specific effect. Taken together, we identified HCV-induced CCL20 as a direct pro-angiogenic factor that acts on endothelial CCR6. These results suggest that the CCL20/CCR6 axis contributes to hepatic angiogenesis, promoting the hypervascular state of HCV-HCC.