The role of the angiogenic molecule VEGF in the pathogenesis of rheumatoid arthritis

Angiopoietin-2, vascular endothelial growth factor family, and heparin binding endothelial growth factor are associated with subclinical atherosclerosis in rheumatoid arthritis

Introduction

Patients with RA are at a higher risk of developing CV diseases than the general population. The precise mechanisms are still unknown. We evaluated the associations between 8 plasma growth factors (GFs) (angiopoietin-2, EGF, HB-EGF, PLGF, TGF-α, VEGFa, VEGFc, and VEGFd) and subclinical arteriosclerosis in RA patients.

Materials and methods

A total of 199 patients with RA treated at the Hospital Universitari Sant Joan de Reus (Spain) between 2011 and 2015 were included in this cross-sectional study. Carotid intima media thickness (cIMT), carotid plaque presence (cPP) and pulse wave velocity (PWV) were measured. GFs were measured with Bio-Plex Pro Human Cancer Biomarker Panel 2 (Bio-Rad). Multivariate models and partial least square discriminant analysis (PLS-DA) were used for analysis (RStudio, version 4.0.1).

Results

Multivariate models showed that angiopoietin-2 was associated with cPP and PWV in the overall cohort (OR = 1.53 and β = 0.20, respectively). VEGFc (β = 0.29), VEGFa (β = 0.26) and HB-EGF (β = 0.22) were also associated with PWV. VEGFa (OR = 2.36), VEGFd (OR = 2.29), EGF (OR = 2.62), PLGF (OR = 2.54), and HB-EGF (OR = 2.24) were associated with cPP in men. According to PLS-DA, GFs were able to distinguish between patients with and without cPP in the overall cohort, male cohort, and female cohort. In women, angiopoietin-2 was associated with PWV (β = 0.18).

Conclusions

The selected GFs were closely related to atherosclerosis in patients with RA and are potential predictors of CV disease in patients with RA.

Comparison and correlation study of synovial ultrasound indices and serum VEGF in rheumatoid wrist arthritis before and after treatment

OBJECTIVE

Rheumatoid wrist arthritis is a chronic autoimmune disease, resulting in joint deformity and functional impairment. We aimed to compare the wrist synovial ultrasound indices and serum vascular endothelial growth factor (VEGF) level in patients with RA before and after treatment, and to explore the correlation between the two.

METHODS

Forty patients with RA in wrist underwent ultrasound examination to determine wrist synovial thickness, synovial blood flow grade, and synovial artery resistive index (RI) before and after treatment. The serum level of VEGF was detected by enzyme-linked immunosorbent assay. Correlation between synovial ultrasound indices and serum VEGF level was assessed.

RESULTS

Pre-treatment synovial thickness, synovial artery RI, and serum VEGF level were 8.60 ± 2.82 mm, 0.62 ± 0.07, and 419.49 ± 19.27 pg/mL, respectively. The corresponding post-treatment levels were 4.05 ± 1.89 mm, 0.83 ± 0.10, and 199.30 ± 16.18 pg/mL. Pre-treatment distribution of synovial blood flow grades was as follows: grade 0, nil; grade I, 1 case; grade II, 17 cases; grade III, 22 cases. The post-treatment distribution was as follows: grade 0, 6 cases; grade I, 23 cases; grade II, 11 cases; and grade III, nil. There were significant differences between pre- and post-treatment wrist synovial thickness, artery RI, and blood flow grading. Wrist synovial thickness and synovial blood flow grade showed a strong positive correlation with serum VEGF level (P < 0.01). There was strong negative correlation between wrist synovial artery RI and serum VEGF level (P < 0.01).

CONCLUSION

The strong correlation between wrist synovial ultrasound indicators and serum VEGF may be clinically useful for diagnosis and therapy.

YWHAH Genetic Variants are Associated with Increased Hypoxia Inducible Factor-1α/Vascular Endothelial Growth Factor in Egyptian Rheumatoid Arthritis Patients

The 14-3-3 Eta (14-3-3 η) biomarker platform is a relatively recent discovery with the potential to significantly address the diagnosis and prognosis of rheumatoid arthritis (RA) disease. Hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) have been implicated in inflammatory mechanisms in RA. We hypothesized a molecular association of the coding YWHAH gene and its expressed protein 14-3-3 η with hypoxia and angiogenesis in RA. One hundred healthy subjects and 100 RA patients were enrolled in the study. YWHAH gene expression was determined using quantitative PCR, and its gene polymorphism rs2858750 was assessed by Taqman genotyping assay. Serum levels of 14-3-3 η, HIF-1α, and VEGF were measured using the ELISA technique, and clinical parameters were routinely examined. In RA patients, significant positive correlations were found between 14-3-3 η, HIF-1α (r = 0.84), and VEGF (r = 0.85). YWHAH gene expression was upregulated 10.8 fold (CI 95% 10.1-11.5) in RA patients and significantly correlated with all disease activity parameters, ACPA, and levels of 14-3-3 η, HIF-1α, and VEGF. RA patients showed a higher frequency of YWHAH rs2858750 A allele than healthy subjects (p = 0.02). The risk A allele carriers showed higher disease activity parameters, ACPA, YWHAH gene expression, and increased serum levels of 14-3-3 η (p < 0.001), HIF-1α (p = 0.002), and VEGF (p = 0.001) than the G allele. Serum 14-3-3 η and its rs2858750 genetic variant are associated with increased hypoxia and angiogenesis in RA and activity, and severity of the disease.

Association of the Adipokines Chemerin, Apelin, Vaspin and Omentin and Their Functional Genetic Variants with Rheumatoid Arthritis

Adipokines were shown to exert crucial roles in rheumatic diseases. This study aimed to assess the role of chemerin, apelin, vaspin, and omentin adipokines and their genetic variants rs17173608, rs2235306, rs2236242, and rs2274907, respectively, in rheumatoid arthritis (RA) pathogenesis in Egyptian patients. A total of 150 RA patients and 150 healthy individuals were recruited. Blood samples were collected and used for genotyping. Serum was separated and used for expression analysis by quantitative PCR, and various biochemical markers determination by ELISA. Serum protein levels of chemerin and vaspin, as well as their gene expression levels were higher, while those of apelin and omentin were lower in RA patients and were associated with most of RA clinical and laboratory characteristics. G allele of chemerin rs17173608, T allele of vaspin rs2236242, and T allele of omentin rs2274907 were more frequent in RA patients. Serum levels and gene expression levels of chemerin in GG genotype carriers and vaspin in TT genotype group were significantly higher, while those of omentin in TT genotype carriers were significantly lower than RA patients with other genotypes. There was no association between apelin rs2235306 and RA. Chemerin rs17173608, vaspin rs2236242, and omentin rs2274907 polymorphisms were associated with increased susceptibility to RA.

Impaired inflammatory state of the endometrium: a multifaceted approach to endometrial inflammation. Current insights and future directions

New insights into the complex and fine-regulated inflammatory mechanisms involved in the endometrium reveal multiple facets to the problem of endometrial inflammation. However, the entity termed chronic endometritis is to date restricted to infectious etiology and managed with antibiotics. Conversely, the concept of impaired inflammatory state of the endometrium (IISE) provides a more global approach to defective endometrial inflammation, considering both infectious and non-infectious etiology. A non-systematic review was done through a search on MEDLINE, EMBASE, Global Health, The Cochrane Library, Health Technology Assessment Database and Web of Science, research registers. Pertinent original and review articles, published in English or French until December 31, 2019, were selected. A compelling body of evidence demonstrates transient, repeated and persistent IISE to be a major factor of most problematic disorders in obstetrics/gynecology, such as endometrial polyps, unexplained infertility, miscarriage, placenta-related pathology and endometrial cancer. When scheduled accordingly, hysteroscopy can play a key role in the IISE assessment. Robust data suggests the pertinence of minimal-effective anti-inflammatory regimens for therapeutic IISE targeting. This review provides a comprehensive update on the multiple facets of inflammation in the endometrial physiology and pathology. Further research is needed to improve classification, diagnosis and treatment of IISE.

Association of Angiogenic and Inflammatory Markers with Power Doppler Ultrasound Vascularity Grade and DAS28-CRP in Early Rheumatoid Arthritis: A Comparative Analysis

Objective

Upregulation of various proinflammatory and angiogenic mediators orchestrates the typical pathological synovial alterations in rheumatoid arthritis (RA). DAS28-CRP is commonly used for assessment of RA disease activity and power Doppler ultrasonography (PDUS) is an important modality for assessing synovial vascularity. This study was intended to look for the association of various inflammatory and angiogenic mediators, with respect to different PDUS vascularity grades and disease activity status, in early RA patients.

Methods

50 early RA patients (<6 months disease duration) with either moderate or high disease activity and 30 healthy controls were included in this study. RA patients were subcategorized based on PDUS vascularity grading of wrist joints. Serum levels of proinflammatory cytokines [tumor necrosis factor-α (TNF- α); interleukin-6(IL-6)] and angiogenic markers [angiopoietin-1 and 2 (Ang-1 and Ang-2); vascular endothelial growth factor (VEGF) ] were measured and compared among different patient subgroups.

Results

Among 50 patients, 22 and 28 patients had moderate and high DAS28-CRP score, respectively. Patients with grade 3 PDUS score, even with moderate DAS value, showed a significant rise in Ang-1 (p<0.02), VEGF (p<0.008), Ang-2 (p <0.001), and TNF-α (p<0.005) level compared to grade 2 PDUS patients with high DAS values.

Conclusion

Higher serum level of angiogenic and inflammatory markers was noted among patients with moderate disease activity but with advanced PDUS vascularity (grade 3) in comparison to high disease activity group with less severe PDUS vascularity (grade 2). PDUS vascularity grading better reflects some markers of angiogenesis and inflammation, than composite disease activity index.

Therapeutic Antibody-Like Immunoconjugates against Tissue Factor with the Potential to Treat Angiogenesis-Dependent as Well as Macrophage-Associated Human Diseases

Accumulating evidence suggests that tissue factor (TF) is selectively expressed in pathological angiogenesis-dependent as well as macrophage-associated human diseases. Pathological angiogenesis, the formation of neovasculature, is involved in many clinically significant human diseases, notably cancer, age-related macular degeneration (AMD), endometriosis and rheumatoid arthritis (RA). Macrophage is involved in the progression of a variety of human diseases, such as atherosclerosis and viral infections (human immunodeficiency virus, HIV and Ebola). It is well documented that TF is selectively expressed on angiogenic vascular endothelial cells (VECs) in these pathological angiogenesis-dependent human diseases and on disease-associated macrophages. Under physiology condition, TF is not expressed by quiescent VECs and monocytes but is solely restricted on some cells (such as pericytes) that are located outside of blood circulation and the inner layer of blood vessel walls. Here, we summarize TF expression on angiogenic VECs, macrophages and other diseased cell types in these human diseases. In cancer, for example, the cancer cells also overexpress TF in solid cancers and leukemia. Moreover, our group recently reported that TF is also expressed by cancer-initiating stem cells (CSCs) and can serve as a novel oncotarget for eradication of CSCs without drug resistance. Furthermore, we review and discuss two generations of TF-targeting therapeutic antibody-like immunoconjugates (ICON and L-ICON1) and antibody-drug conjugates that are currently being tested in preclinical and clinical studies for the treatment of some of these human diseases. If efficacy and safety are proven in current and future clinical trials, TF-targeting immunoconjugates may provide novel therapeutic approaches with potential to broadly impact the treatment regimen of these significant angiogenesis-dependent, as well as macrophage-associated, human diseases.

Anti-angiogenic effects of biotechnological therapies in rheumatic diseases

Introduction

Angiogenesis plays a key role in the pathogenesis of numerous rheumatic diseases, such as rheumatoid arthritis, psoriatic arthritis, and vasculitides. Therefore, the inhibition of pathological angiogenesis may be considered a useful therapeutical approach in these rheumatic diseases.

Methods

This review article is based on a literature research about the role of biotechnological therapies in angiogenesis inhibition.

Results and conclusions

Several evidences have demonstrated a role for biotechnological therapies in angiogenesis inhibition. Nevertheless, further research and clinical trials are needed to better quantify the real impact of biotechnological therapies on pathological angiogenesis.

Adenovirus-mediated delivery of Sema3A alleviates rheumatoid arthritis in a serum-transfer induced mouse model

Rheumatoid arthritis is a chronic autoimmune disease characterized by infiltration of inflammatory cells into the synovium and destruction of cartilage and bone. Macrophages, fibroblast-like synoviocytes (FLS), and osteoclasts are critical cells driving the pathogenesis of RA. Semaphorin 3A (Sema3A) is recently identified as an essential player in the bone homeostasis, however its role in RA progression especially in the macrophage polarization are poorly understood. In the present study, we found that Sems3A levels were significantly decreased in RA serum and synovial fluid compared to OA controls. There was a negative correlation between Sema3A levels and RA severity. Using in vitro cell cultures, we showed for the first time that Sema3A promoted IL-4 induced M2 macrophage polarization, whereas prohibited LPS/IFN-γ induced M1 polarization. Sema3A inhibited VEGF-induced endothelial cells proliferation and migration, suppressed VEGF-mediated invasion and IL-6 production of FLS while stimulating their apoptosis. In addition, Sema3A retarded osteoclastogenesis. In vivo data demonstrated that Sema3A administration attenuated joint tissue damage and the severity of experimental arthritis. Our findings uncovered Sema3A as a promising diagnostic biomarker and novel prevention and treatment strategies in arthritis treatment.

Tissue factor is an angiogenic-specific receptor for factor VII-targeted immunotherapy and photodynamic therapy

Identification of target molecules specific for angiogenic vascular endothelial cells (VEC), the inner layer of pathological neovasculature, is critical for discovery and development of neovascular-targeting therapy for angiogenesis-dependent human diseases, notably cancer, macular degeneration and endometriosis, in which vascular endothelial growth factor (VEGF) plays a central pathophysiological role. Using VEGF-stimulated vascular endothelial cells (VECs) isolated from microvessels, venous and arterial blood vessels as in vitro angiogenic models and unstimulated VECs as a quiescent VEC model, we examined the expression of tissue factor (TF), a membrane-bound receptor on the angiogenic VEC models compared with quiescent VEC controls. We found that TF is specifically expressed on angiogenic VECs in a time-dependent manner in microvessels, venous and arterial vessels. TF-targeted therapeutic agents, including factor VII (fVII)-IgG1 Fc and fVII-conjugated photosensitizer, can selectively bind angiogenic VECs, but not the quiescent VECs. Moreover, fVII-targeted photodynamic therapy can selectively and completely eradicate angiogenic VECs. We conclude that TF is an angiogenic-specific receptor and the target molecule for fVII-targeted therapeutics. This study supports clinical trials of TF-targeted therapeutics for the treatment of angiogenesis-dependent diseases such as cancer, macular degeneration and endometriosis.

Safety and patient response as indicated by biomarker changes to binding immunoglobulin protein in the phase I/IIA RAGULA clinical trial in rheumatoid arthritis

OBJECTIVES

Binding immunoglobulin protein (BiP) is a human endoplasmic reticulum-resident stress protein. In pre-clinical studies it has anti-inflammatory properties due to the induction of regulatory cells. This randomized placebo-controlled, dose ascending double blind phase I/IIA trial of BiP in patients with active RA, who had failed accepted therapies, had the primary objective of safety. Potential efficacy was measured by DAS28-ESR and changes in biomarkers.

METHODS

Twenty-four patients with active RA who had failed one or more DMARDs were sequentially assigned to three groups each of eight patients randomly allocated to receive placebo (two patients) or BiP (six patients), 1, 5 or 15 mg. Patients received a single i.v. infusion over 1 h and were observed as inpatients overnight. A 12-week follow-up for clinical, rheumatological and laboratory assessments for safety, efficacy (DAS28-ESR) and biomarker analysis was performed.

RESULTS

No infusion reactions or serious adverse drug reactions were noted. Adverse events were evenly distributed between placebo and BiP groups with no BiP-related toxicities. Haematological, renal and metabolic parameters showed no drug-related toxicities. Remission was only achieved by patients in the 5 and 15 mg groups, and not patients who received placebo or 1 mg BiP. Good DAS28-ESR responses were achieved in all treatment groups. The BiP responding patients showed significantly lower serum concentrations of CRP, 2 weeks post-infusion compared with pre-infusion levels, and of VEGF and IL-8 from the placebo group.

CONCLUSION

BiP (⩽15 mg) is safe in patients with active RA. Some patients had clinical and biological improvements in RA activity. BiP merits further study.

TRIAL REGISTRATION

ISRCTN registry, http://isrctn.com, ISRCTN22288225 and EudraCT, https://eudract.ema.europa.eu, 2011-005831-19.

Investigation of the cytokine response to NF-κB decoy oligonucleotide coated polysaccharide based nanoparticles in rheumatoid arthritis in vitro models

Introduction

The transcription factor nuclear factor-kappa B (NF-κB) is highly involved in regulation of a number of cellular processes, including production of inflammatory mediators. Thus, this transcription factor plays a role in pathology of many diseases, including rheumatoid arthritis, an autoimmune disease hallmarked by an imbalance of pro and anti-inflammatory cytokines. Small nucleic acids with sequences that mimic the native binding site of NF-κB have been proposed as treatment options for RA; however due to low cellular penetration and a high degree of instability, clinical applications of these therapeutics have been limited.

Methods

Here, we describe the use of N-trimethyl chitosan-polysialic acid (PSA-TMC) nanoparticles coated with decoy oligodeoxynucleotides (ODNs) specific to transcription factor NF-κB (PSA-TMC-ODN) as a method to enhance the stability of the nucleic acids and facilitate increased cellular penetration. In addition to decoy ODN, PSA-TMC nanoparticles were loaded with RA therapeutic methotrexate (MTX), to assess the anti-inflammatory efficacy of a combination therapy approach. Two different in vitro models, a cell line based model as well as a primary RA cell model were used to investigate anti-inflammatory activity. One way ANOVA followed by Holm-Sidak stepdown comparisons was used to determine statistical significance.

Results

In general, free ODN did not significantly affect secretion of pro-inflammatory cytokines interleukin-6 (IL-6) and interleukin-8, (IL-8) while free MTX had variable efficacy. However, PSA-TMC-ODN and PSA-TMC-ODN-MTX resulted in significant decreases in the inflammatory mediators IL-6 and IL-8 in both cell models. In addition, PSA-TMC exhibited sufficient cellular uptake, as observed through fluorescence microscopy.

Conclusions

These results support our previous findings that PSA-TMC nanoparticles are an effective delivery vehicle for small nucleic acids, and effectively alter the pro-inflammatory state characteristic of RA.

Measurement of serum and vitreous concentrations of anti-type II collagen antibody in diabetic retinopathy

Background

Autoimmune mechanisms have been postulated as a cause of diabetic retinopathy (DR), as several autoantibodies have reportedly been detected in the serum of DR patients. In this present study, we measured serum and vitreous levels of anti-type II collagen (anti-II-C) antibodies in DR patients and investigated their association with the mechanism of development of DR.

Patients and methods

Blood samples were obtained from patients with proliferative DR and from patients with diabetic macular edema who underwent vitrectomy at Osaka Medical College, Takatsuki City, Osaka, Japan. Diabetic patients without DR were also included. The control group consisted of age- and sex-matched patients with noninflammatory eye diseases who underwent eye surgery for retinal detachment or for cataracts. The levels of anti-II-C immunoglobulin (Ig)G antibody in the vitreous and serum were measured using a human/monkey anti-II-C IgG assay kit.

Results

The serum levels of anti-II-C IgG antibody were significantly higher in the DR patients than in the patients with noninflammatory eye disease (56.8±33.8 units/mL versus 30.5±13.7 units/mL, respectively; P<0.05, Fisher’s exact test). These levels were also significantly higher in the diabetic patients without DR than in the patients with noninflammatory eye disease (76.3±49.7 units/mL versus 30.5±13.7 units/mL, respectively; P<0.01, Fisher’s exact test). However, anti-II-C IgG antibody levels were unable to be detected in all of the obtained vitreous fluid samples.

Conclusion

The development and progression of DR may be related to a mechanism involving intraocular type II collagen, which normally has immunological tolerance as a sequestered antigen. In DR, the disruption of the blood–retinal barrier leads to contact between the intraocular type II collagen and immunocompetent cells, and to subsequent activation of the autoimmune mechanism.

Aryl hydrocarbon receptor antagonism attenuates growth factor expression, proliferation, and migration in fibroblast-like synoviocytes from patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease with high morbidity and mortality. Within the inflammatory milieu, resident fibroblast-like synoviocytes (FLS) in the synovial tissue undergo hyperplasia, which leads to joint destruction. Epidemiologic studies and our previous research suggest that activation of the aryl hydrocarbon receptor (AHR) pathway plays an instrumental role in the inflammatory and destructive RA phenotype. In addition, our recent studies implicate the AHR in the regulation of the expression of several growth factors in established tumor cell lines. Thus, under inflammatory conditions, we hypothesized that the AHR is involved in the constitutive and inducible expression of several growth factors, FLS proliferation and migration, along with protease-dependent invasion in FLS from patients with RA (RA-FLS). Treatment with the AHR antagonist GNF351 inhibits cytokine-induced expression of vascular endothelial growth factor-A (VEGF-A), epiregulin, amphiregulin, and basic fibroblast growth factor mRNA through an AHR-dependent mechanism in both RA-FLS and FLS. Secretion of VEGF-A and epiregulin from RA-FLS was also inhibited upon GNF351 treatment. RA-FLS cell migration, along with cytokine-induced RA-FLS cell proliferation, was significantly attenuated by GNF351 exposure. Treatment of RA-FLS with GNF351 mitigated cytokine-mediated expression of matrix metalloproteinase-2 and -9 mRNA and diminished the RA-FLS invasive phenotype. These findings indicate that inhibition of AHR activity may be a viable therapeutic target in amelioration of disease progression in RA by attenuating growth factor release; FLS proliferation, migration, and invasion; and inflammatory activity.

TNF-α, IFN-γ, IL-10, and IL-4 levels were elevated in a murine model of human sickle cell anemia maintained on a high protein/calorie diet

Increased frequency and risk of infection is one of the well described complications of sickle cell anemia (SCA). Dietary supplementation in children with SCA and growth retardation improved growth and decreased incidence of infection. We investigated the impact of a high protein diet on weight gain, hematological profile, and immune cytokine levels in the Berkeley model of SCA, 16 of which were randomized to either regular mouse diet with 20% of calories from protein (n = 8) or a test feed with 35% of calories from protein (n = 8). Control mice (C57BL/6, n = 16) were correspondingly randomized, and were all feed ad libitum for three months with actual intake estimated by subtracting the weight of gnaw waste from that of the feed given. Blood was collected at sacrifice by cardiac puncture and plasma levels of T helper cell 1 (TH1) and TH2 associated cytokines were measured using a multiplex antibody immobilized bead assay. SCA mice receiving the 35% protein diet had modest improvements in weight, red blood cell count, and hemoglobin level, with a slight decrease in reticulocyte count compared with SCA mice on the regular mouse diet. Furthermore, they also had significantly higher plasma levels of cytokines tumor necrosis factor (TNF)-α (P = 0.02), interferon (IFN)-γ (P = 0.01), interleukin 10 (IL-10; P = 0.02), and IL-4 (P = 0.02) compared with those that received the 20% protein diet. We conclude that providing additional protein calories to transgenic SCA mice increased the plasma levels of acute inflammatory cytokines associated with immune response to infection, which might partly explain decreased episodes of infection observed among supplemented children with SCA.

Physiological variables associated with the development of acute mountain sickness at the South Pole

Exposure to altitudes >2500 m can result in acute mountain sickness (AMS), a mild and usually self-limiting condition. Research has attempted to identify factors associated with developing AMS without controlling important factors related to the ascent or collecting a comprehensive set of variables.

OBJECTIVES

The Antarctic Study of Altitude Physiology (ASAP) investigated variables associated with the development of AMS in adults experiencing rapid passive transport to altitude by airplane.

DESIGN

Our prospective observational trial collected data, including personal history, anthropometrics, vital signs, blood samples and pulmonary function, at sea level and at altitude. Statistical analysis utilised independent sample t tests to investigate between-group differences (p<0.05) and a forward, step-wise binary logisitic regression analysis was performed.

PARTICIPANTS

Of 248 eligible ASAP participants, those who did not use acetazolamide (N=98) were included in the present analysis.

PRIMARY OUTCOME MEASURES

The diagnosis of AMS using the Lake Louise Symptom Score.

RESULTS

Analysis of participants not using acetazolamide (n=90) found 30 participants developed AMS and 60 participants did not. Estimated plasma volume decreased significantly at altitude (p=0.025) in the AMS group as compared with the No AMS group while body weight did not change (p=0.125). Serum sodium (p=0.045) and low-density lipoprotein (LDL) (p=0.049) levels were higher in the No AMS group. A logistic regression analysis emphasised the contributions of LDL and eosinophil levels in the development of AMS.

CONCLUSIONS

These results suggest that the body water regulation and inflammation are key factors in AMS development when all other factors such as the level of physical exertion during ascent, the rate and magnitude of ascent and the use of acetazolamide are controlled.

Gene expression profiling and functional analysis of angiogenic markers in murine collagen-induced arthritis

Introduction

Dysregulated angiogenesis is implicated in the pathogenesis of rheumatoid arthritis (RA). To provide a more profound understanding of arthritis-associated angiogenesis, we evaluated the expression of angiogenesis-modulating genes at onset, peak and declining phases of collagen-induced arthritis (CIA), a well-established mouse model for RA.

Methods

CIA was induced in DBA/1 mice with type II collagen. Functional capillary density in synovial tissue of knee joints was determined by intravital fluorescence microscopy. To assess the ability of arthritic joint homogenates to induce angiogenesis, an endothelial chemotaxis assay and an in vivo matrigel plug assay were employed. The temporal expression profile of angiogenesis-related genes in arthritic paws was analysed by quantitative real-time RT-PCR using an angiogenesis focused array as well as gene specific PCR. Finally, we investigated the therapeutic effect of a monoclonal antibody specifically blocking the binding of VEGF to neuropilin (NRP)-1.

Results

Although arthritic paw homogenates displayed angiogenic activity in vitro and in vivo, and synovia of arthritic paws appeared highly vascularised on histological examination, the functional capillary density in arthritic knee synovia was significantly decreased, whereas capillary diameter was increased. Of the 84 genes analysed, 41 displayed a differential expression in arthritic paws as compared to control paws. Most significant alterations were seen at the peak of clinical arthritis. Increased mRNA expression could be observed for VEGF receptors (Flt-1, Flk-1, Nrp-1, Nrp-2), as well as for midkine, hepatocyte growth factor, insulin-like growth factor-1 and angiopoietin-1. Signalling through NRP-1 accounted in part for the chemotactic activity for endothelial cells observed in arthritic paw homogenates. Importantly, therapeutic administration of anti-NRP1^B antibody significantly reduced disease severity and progression in CIA mice.

Conclusions

Our findings confirm that the arthritic synovium in murine CIA is a site of active angiogenesis, but an altered balance in the expression of angiogenic factors seems to favour the formation of non-functional and dilated capillaries. Furthermore, our results validate NRP-1 as a key player in the pathogenesis of CIA, and support the VEGF/VEGF receptor pathway as a potential therapeutic target in RA.

Interleukin-7-aggravated joint inflammation and tissue destruction in collagen-induced arthritis is associated with T-cell and B-cell activation

Introduction

We sought to investigate the capacity of interleukin (IL)-7 to enhance collagen-induced arthritis and to study by what mechanisms this is achieved.

Methods

Mice received multiple injections with IL-7 or phosphate-buffered saline (PBS) as a control. Arthritis severity and incidence were determined by visual examination of the paws. Joint destruction was determined by assessing radiographs and immunohistochemistry of the ankle joints. Total cellularity and numbers of T-cell and B-cell subsets were assessed, as well as ex vivo production of interferon-γ (IFN-γ), IL-17, and IL-4. Proinflammatory mediators were measured in serum with multianalyte profiling.

Results

IL-7 increased arthritis severity and radiology-assessed joint destruction. This was consistent with IL-7-increased intensity of cell infiltrates, bone erosions, and cartilage damage. Splenic CD19⁺ B cells and CD19⁺/GL7⁺ germinal center B cells, as well as CD4 and CD8 numbers, were increased by IL-7. IL-7 expanded memory T cells, associated with increased percentages of IFN-γ-, IL-4-, and IL-17-producing CD4⁺ T cells. On antigen restimulation of draining lymph node cells in vitro IL-7 treatment was found to increase IFN-γ and IL-17 production, whereas IL-4 was reduced. IL-7 also increased concentrations of proinflammatory mediators, indicative of T-cell activation (sCD40L), vascular activation (VCAM-1, VEGF), tissue destruction (fibroblast growth factor-basic (FGF-b), LIF), and chemotaxis (MIP-1γ, MIP-3β, lymphotactin, MDC, and MCP-5).

Conclusions

In arthritic mice, IL-7 causes expansion of T and B cells, associated with increased levels of proinflammatory mediators. IL-7 intensifies arthritis severity and joint destruction, accompanied by increased Th1 and Th17 activity. These data indicate that IL-7 could be an important mediator in arthritic conditions and that targeting IL-7 or its receptor represent novel therapeutic strategies.

Terminal differentiation is not a major determinant for the success of stem cell therapy - cross-talk between muscle-derived stem cells and host cells

We have found that when muscle-derived stem cells (MDSCs) are implanted into a variety of tissues only a small fraction of the donor cells can be found within the regenerated tissues and the vast majority of cells are host derived. This observation has also been documented by other investigators using a variety of different stem cell types. It is speculated that the transplanted stem cells release factors that modulate repair indirectly by mobilizing the host's cells and attracting them to the injury site in a paracrine manner. This process is loosely called a 'paracrine mechanism', but its effects are not necessarily restricted to the injury site. In support of this speculation, it has been reported that increasing angiogenesis leads to an improvement of cardiac function, while inhibiting angiogenesis reduces the regeneration capacity of the stem cells in the injured vascularized tissues. This observation supports the finding that most of the cells that contribute to the repair process are indeed chemo-attracted to the injury site, potentially through host neo-angiogenesis. Since it has recently been observed that cells residing within the walls of blood vessels (endothelial cells and pericytes) appear to represent an origin for post-natal stem cells, it is tempting to hypothesize that the promotion of tissue repair, via neo-angiogenesis, involves these blood vessel-derived stem cells. For non-vascularized tissues, such as articular cartilage, the regenerative property of the injected stem cells still promotes a paracrine, or bystander, effect, which involves the resident cells found within the injured microenvironment, albeit not through the promotion of angiogenesis. In this paper, we review the current knowledge of post-natal stem cell therapy and demonstrate the influence that implanted stem cells have on the tissue regeneration and repair process. We argue that the terminal differentiation capacity of implanted stem cells is not the major determinant of the cells regenerative potential and that the paracrine effect imparted by the transplanted cells plays a greater role in the regeneration process.

Intravenous administration of anti-vascular endothelial growth factor humanized monoclonal antibody bevacizumab improves articular cartilage repair

Introduction

In this study, we investigate the efficacy of repairing an osteochondral defect in rabbit knee joints by administering bevacizumab, a humanized monoclonal anti-vascular endothelial growth factor (VEGF) antibody.

Methods

An osteochondral defect was created on the patellar groove of 20 Japanese white rabbits that were classified into two recipient groups: group B, administration of bevacizumab (100-mg intravenous injection on the day of surgery and 2 weeks later), and a control group (defect only). Rabbits were killed 1 and 3 months postoperatively. Sections were stained with safranin O. Repair sites were evaluated using the modified O'Driscoll International Cartilage Repair Society grading system. The expression of chondromodulin (ChM)-I and VEGF was evaluated using immunohistochemical analyses.

Results

At 1 month postoperatively, the repair site in group B was filled with cartilaginous tissue. At 3 months, the repair site retained this cartilage phenotype. At 1 month in the controls, the defects were mainly filled with fibrous tissue. At 3 months, the defect was replaced by fibrous tissue and bone. Over the 3-month period, histological scores were significantly higher in group B than in the controls. At 1 month, group B showed intense positive results for ChM-I in the bottom of the repair tissue. VEGF was also identified in the same area. In the controls, no ChM-I was observed in the repair tissue. Conversely, the remodeling hypertrophic chondrocyte layer stained intensely for VEGF.

Conclusions

Intravenous administration of bevacizumab contributes to better repair of articular cartilage in an osteochondral defect model. We suggest the possibility of facilitating articular cartilage repair with anti-VEGF antibody rather than using cultured cells or artificial scaffolds.

Extracellular ATP may contribute to tissue repair by rapidly stimulating purinergic receptor X7-dependent vascular endothelial growth factor release from primary human monocytes

Extracellular ATP has been proposed to act as a danger signal to alert the immune system of cell damage. Release of high local concentrations of ATP activates the nucleotide receptor, purinergic receptor X7 (P2RX7), on monocytic cells, which promotes the processing/release of proinflammatory mediators. Although the proinflammatory actions of P2RX7 are well recognized, little is known regarding the potential function of P2RX7 in repair responses. Because the resolution of inflammation is characterized by monocytic cell-dependent production of proangiogenic factors, we evaluated the contribution of P2RX7 to this process. We observed that both short-term and long-term P2RX7 activation promotes the robust release of vascular endothelial growth factor from primary human monocytes. This vascular endothelial growth factor release is calcium dependent and associated with reactive oxygen species production. This previously unrecognized action of P2RX7 suggests that it may not only participate in inflammation and cell death, but that it is also likely to be important in the control of angiogenesis and wound repair.

Blocking vascular endothelial growth factor with soluble Flt-1 improves the chondrogenic potential of mouse skeletal muscle-derived stem cells

OBJECTIVE

To investigate the effect of vascular endothelial growth factor (VEGF) stimulation and the effect of blocking VEGF with its antagonist, soluble Flt-1 (sFlt-1), on chondrogenesis, using muscle-derived stem cells (MDSCs) isolated from mouse skeletal muscle.

METHODS

The direct effect of VEGF on the in vitro chondrogenic ability of mouse MDSCs was tested using a pellet culture system, followed by real-time quantitative polymerase chain reaction (PCR) and histologic analyses. Next, the effect of VEGF on chondrogenesis within the synovial joint was tested, using genetically engineered MDSCs implanted into rat osteochondral defects. In this model, MDSCs transduced with a retroviral vector to express bone morphogenetic protein 4 (BMP-4) were coimplanted with MDSCs transduced to express either VEGF or sFlt-1 (a VEGF antagonist) to provide a gain- and loss-of-function experimental design. Histologic scoring was used to compare cartilage formation among the treatment groups.

RESULTS

Hyaline-like cartilage matrix production was observed in both VEGF-treated and VEGF-blocked (sFlt-1-treated) pellet cultures, but quantitative PCR revealed that sFlt-1 treatment improved the expression of chondrogenic genes in MDSCs that were stimulated to undergo chondrogenic differentiation with BMP-4 and transforming growth factor beta3 (TGFbeta3). In vivo testing of articular cartilage repair showed that VEGF-transduced MDSCs caused an arthritic change in the knee joint, and sFlt-1 improved the MDSC-mediated repair of articular cartilage, compared with BMP-4 alone.

CONCLUSION

Soluble Flt-1 gene therapy improved the BMP-4- and TGFbeta3-induced chondrogenic gene expression of MDSCs in vitro and improved the persistence of articular cartilage repair by preventing vascularization and bone invasion into the repaired articular cartilage.

Alteration of protein expression pattern of vascular endothelial growth factor (VEGF) from soluble to cell-associated isoform during tumourigenesis

Background

Vascular endothelial growth factor (VEGF) is a potent mitogen for endothelial cells, and its expression has been correlated with increased tumour angiogenesis. Although numerous publications dealing with the measurement of circulating VEGF for diagnostic and therapeutic monitoring have been published, the relationship between the production of tissue VEGF and its concentration in blood is still unclear. The aims of this study were to determine: 1) The expression pattern of VEGF isoforms at the protein level in colorectal and lung adenocarcinoma in comparison to the pattern in corresponding adjacent normal tissues 2) The relationship between the expression pattern of VEGF and total level of circulating VEGF in the blood to clarify whether the results of measuring circulating VEGF can be used to predict VEGF expression in tumour tissues.

Methods

Ninety-four tissue samples were obtained from patients, 76 colorectal tumour tissues and 18 lung tumour tissues. VEGF protein expression pattern and total circulating VEGF were examined using western blot and capture ELISA, respectively.

Results

Three major protein bands were predominately detected in tumour samples with an apparent molecular mass under reducing conditions of 18, 23 and 26 kDa. The 18 kDa VEGF protein was expressed equally in both normal and colorectal tumour tissues and predominately expressed in normal tissues of lung, whereas the 23 and 26 kDa protein was only detected at higher levels in tumour tissues. The 18, 23 and 26 kDa proteins are believed to represent the VEGF₁₂₁, the VEGF₁₆₅ and the VEGF₁₈₉, respectively. There was a significant correlation of the expression of VEGF₁₆₅ with a smaller tumour size maximum diameter <5 cm (p < 0.05), and there was a significant correlation of VEGF₁₈₉ with advanced clinical stage of colorectal tumours. The measurement of total circulating VEGF in serum revealed that cancer patients significantly (p < 0.001) possessed a higher level of circulating VEGF (1081 ± 652 pg/ml in colorectal and 1,251 ± 568 pg/ml in lung) than a healthy volunteer group (543 ± 344 pg/ml). No correlation between the level of circulating VEGF and the pathologic features of tumours was observed.

Conclusion

Our findings indicate that the expression patterns of VEGF isoforms are altered during tumourigenesis as certain isoform overexpression in tumour tissues correlated with tumour progression indicating their important role in tumour development. However, measurement of VEGF in the circulation as a prognostic marker needs to be carefully evaluated as the cell-associated isoform (VEGF₁₈₉), but not the soluble isoform (VEGF₁₂₁ and VEGF₁₆₅) appears to play important role in tumour progression.