Angiogenesis markers (VEGF, soluble receptor of VEGF and angiopoietin-1) in very early arthritis and their association with inflammation and joint destruction

Where are we in targeting hypoxia-induced pathways in inflammatory arthritis? Current understanding, insights, and future directions

INTRODUCTION

Joint tissues affected by inflammatory arthritis (IA) create hypoxic microenvironments that sustain the inflammatory response. Although targeting molecules in hypoxia-induced pathways has provided valuable insights into potential novel therapies for various types of IA, progress remains preclinical, and no clinical trials have been conducted for IA.

METHODS

A literature search was conducted to create a narrative review exploring the role of hypoxia and its signaling pathways in IA pathogenesis, as well as the potential and future directions for IA therapies that target hypoxia-induced molecules before moving forward to clinical applications.

RESULTS

Hypoxia is a prevalent feature of the IA synovial microenvironment and contributes to disease progression. Various studies and preclinical models demonstrate how hypoxia-inducible factors, vascular endothelial growth factors, and matrix metalloproteinases, among other molecules, influence rheumatoid arthritis, axial spondyloarthritis, psoriatic arthritis, and juvenile idiopathic arthritis. Despite these findings, drug development targeting these molecules in IA has been limited due to challenges in delineating the mechanistic pathways of hypoxia, the distinct roles of hypoxia-induced molecules depending on anatomical sites, and concerns regarding pharmacokinetics and patient safety. However, given that hypoxia-induced molecule-targeting therapies have been successfully approved for treating cancers and cardiovascular diseases, further research is needed to advance the application of similar medications in IA.

CONCLUSIONS

Given the pathogenic effects of hypoxic microenvironments in IA, it is imperative to continue gathering compelling evidence to advance hypoxia-induced therapies. Furthermore, elucidating the safety and efficacy of such drugs in various preclinical models, in collaboration with chemists and the pharmaceutical industry, is crucial for accelerating the development of novel, optimized treatment methods.

Soluble FLT-1 in angiogenesis: pathophysiological roles and therapeutic implications

Fine-tuning angiogenesis, the development of new blood vessels, is essential for maintaining a healthy circulatory and lymphatic system. The small glycoprotein vascular endothelial growth factors (VEGF) are the key mediators in this process, binding to their corresponding membrane-bound VEGF receptors (VEGFRs) to activate angiogenesis signaling pathways. These pathways are crucial throughout human life as they are involved in lymphatic and vascular endothelial cell permeability, migration, proliferation, and survival. Neovascularization, the formation of abnormal blood vessels, occurs when there is a dysregulation of angiogenesis and can result in debilitating disease. Hence, VEGFRs have been widely studied to understand their role in disease-causing angiogenesis. VEGFR1, also known as Fms-like tyrosine kinase-1 (FLT-1), is also found in a soluble form, soluble FLT-1 or sFLT-1, which is known to act as a VEGF neutralizer. It is incorporated into anti-VEGF therapy, designed to treat diseases caused by neovascularization. Here we review the journey of sFLT-1 discovery and delve into the alternative splicing mechanism that creates the soluble receptor, its prevalence in disease states, and its use in current and future potential therapies.

Mechanisms of vascular invasion after cartilage injury and potential engineering cartilage treatment strategies

Articular cartilage injury is one of the most common diseases in orthopedic clinics. Following an articular cartilage injury, an inability to resist vascular invasion can result in cartilage calcification by newly formed blood vessels. This process ultimately leads to the loss of joint function, significantly impacting the patient's quality of life. As a result, developing anti-angiogenic methods to repair damaged cartilage has become a popular research topic. Despite this, tissue engineering, as an anti-angiogenic strategy in cartilage injury repair, has not yet been adequately investigated. This exhaustive literature review mainly focused on the process and mechanism of vascular invasion in articular cartilage injury repair and summarized the major regulatory factors and signaling pathways affecting angiogenesis in the process of cartilage injury. We aimed to discuss several potential methods for engineering cartilage repair with anti-angiogenic strategies. Three anti-angiogenic tissue engineering methods were identified, including administering angiogenesis inhibitors, applying scaffolds to manage angiogenesis, and utilizing in vitro bioreactors to enhance the therapeutic properties of cultured chondrocytes. The advantages and disadvantages of each strategy were also analyzed. By exploring these anti-angiogenic tissue engineering methods, we hope to provide guidance for researchers in related fields for future research and development in cartilage repair.

The Effects and Potential Mechanisms of Moxibustion for Rheumatoid Arthritis-Related Pain: A Randomized, Controlled Trial

Purpose

To investigate the effects of moxibustion in relieving pain, and other clinical symptoms for patients with rheumatoid arthritis (RA), and explore the potential mechanism of moxibustion treatment for RA.

Patients and Methods

Seventy qualified RA patients were randomly assigned in a 1:1 ratio to the moxibustion group or the routine group. The routine group only took oral methotrexate tablets and folic acid tablets. The moxibustion group was treated with moxibustion based on oral pharmaceutical. Moxibustion was performed two times weekly for 8 weeks, a total of 16 sessions. Patients scored their pain on a visual analog scale (VAS). The American College of Rheumatology improvement criteria of 20%, 50% and 70% (ACR20, ACR50 and ACR70) after treatment were investigated. Clinical symptoms, a disease activity score using 28 joint counts (DAS28), simplified disease activity index (SDAI), clinical disease activity index (CDAI), health assessment questionnaire (HAQ), interleukin 1β (IL-1β), tumor necrosis factor-alpha (TNF-α), and vascular endothelial growth factor (VEGF) of RA patients were analyzed before and after treatment.

Results

After treatment, the VAS scores, tender and swollen joint counts, morning stiffness scores, disease activity scores (DAS28, SDAI, CDAI), HAQ scores in the two groups were both improved, and the effects of moxibustion group were more obvious (P < 0.05). The ACR20 and ACR50 of the moxibustion group were greater than that of the routine group (P < 0.05), no significant difference of the ACR70 existed between the two groups (P > 0.05). In addition, the decreases of IL-1β, TNF-α, VEGF of the moxibustion group were better than that of the routine group (P < 0.05).

Conclusion

Moxibustion could effectively relieve pain, ameliorate the clinical symptoms, and decrease the disease activity of RA. The potential mechanism may be the decrease in the level of serum inflammatory factors.

MMP-13, VEGF, and Disease Activity in a Cohort of Rheumatoid Arthritis Patients

Identifying certain serum biomarkers associated with the degree of rheumatoid arthritis (RA) activity can provide us with a more accurate view of the evolution, prognosis, and future quality of life for these patients. Our aim was to analyze the presence and clinical use of matrix metalloproteinase-13 (MMP-13), along with vascular endothelial growth factor (VEGF) and well-known cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) for patients with RA. We also wanted to identify the possible correlations between MMP-13 and these serological markers, as well as their relationship with disease activity indices, quality of life, and ultrasonographic evaluation. For this purpose, we analyzed serum samples of 34 RA patients and 12 controls. In order to assess serum concentrations for MMP-13, VEGF, TNF-α, and IL-6, we used the enzyme-linked immunosorbent assay (ELISA) technique. Our results concluded that higher levels of MMP-13, VEGF, TNF-α, and IL-6 were present in the serum of RA patients compared to controls, with statistical significance. We furthermore identified moderately positive correlations between VEGF, MMP-13, and disease activity indices, as well as with the ultrasound findings. We also observed that VEGF had the best accuracy (97.80%), for differentiating patients with moderate disease activity. According to the data obtained in our study, that although MMP-13, TNF-α and C-reactive protein (CRP) have the same sensitivity (55.56%), MMP-13 has a better specificity (86.67%) in the diagnosis of patients with DAS28(4v) CRP values corresponding to moderate disease activity. Thus, MMP-13 can be used as a biomarker that can differentiate patients with moderate or low disease activity. VEGF and MMP-13 can be used as additional parameters, along with TNF-α and IL-6, that can provide the clinician a better picture of the inflammatory process, disease activity, and structural damage in patients with RA. Our data can certainly constitute a start point for future research and extended studies with multicenter involvement, to support the selection of individualized and accurate therapeutic management strategies for our patients.

Relevance of circulating markers of endothelial activation for cardiovascular risk assessment in rheumatoid arthritis: a narrative review

Rheumatoid arthritis (RA) is associated with excessive cardiovascular mortality secondary to premature atherosclerosis, in which endothelial activation (EA) plays a central role. EA is characterized by loss of vascular integrity, expression of leucocyte adhesion molecules, transition from antithrombotic to prothrombotic phenotype, cytokines production, shedding of membrane microparticles and recruitment of endothelial progenitor cells. As EA is an early event in atherogenesis, circulating markers of EA are putative markers of vascular pathology and cardiovascular (CV) risk. After a presentation of biology of EA, the present review analyzed the available data regarding changes in EA markers in RA in link with the vascular pathology and CV events, discussed their relevance as biomarkers of CV risk and proposed future directions.

Gender differences and pharmacological regulation of angiogenesis induced by synovial fluids in inflammatory arthritis

Several mediators including cytokines, growth factors and metalloproteinases (MMP) modulate pathological angiogenesis associated with inflammatory arthritis. The biological factors underlying sex disparities in the incidence and severity of rheumatic musculoskeletal diseases are only partially understood. We hypothesized that synovial fluids (SFs) from rheumatoid arthritis (RA) and psoriatic arthritis (PsA) patients would impact on endothelial biology in a sexually dimorphic fashion. Immune cell counts and levels of pro-angiogenic cytokines found in SFs from RA and PsA patients (n = 17) were higher than in osteoarthritis patients (n = 6). Synovial VEGF concentration was significantly higher in male than in female RA patients. Zymography revealed that SFs comprised solely MMP-9 and MMP-2, with significantly higher MMP-9 levels in male than female RA patients. Using in vitro approaches that mimic the major steps of the angiogenic process, SFs from RA and PsA patients induced endothelial migration and formation of capillary-like structures compared to control. Notably, endothelial cells from female donors displayed enhanced angiogenic response to SFs with respect to males. Treatment with the established anti-angiogenic agent digitoxin prevented activation of focal adhesion kinase and SF-induced in vitro angiogenesis. Thus, despite higher synovial VEGF and MMP-9 levels in male patients, the responsiveness of vascular endothelium to SF priming was higher in females, suggesting that gender differences in angiogenic responses were mainly related to the endothelial genotype. These findings may have implications for pathogenesis and targeted therapies of inflammatory arthritis.

Systematic Review: Targeted Molecular Imaging of Angiogenesis and Its Mediators in Rheumatoid Arthritis

Extensive angiogenesis is a characteristic feature in the synovial tissue of rheumatoid arthritis (RA) from a very early stage of the disease onward and constitutes a crucial event for the development of the proliferative synovium. This process is markedly intensified in patients with prolonged disease duration, high disease activity, disease severity, and significant inflammatory cell infiltration. Angiogenesis is therefore an interesting target for the development of new therapeutic approaches as well as disease monitoring strategies in RA. To this end, nuclear imaging modalities represent valuable non-invasive tools that can selectively target molecular markers of angiogenesis and accurately and quantitatively track molecular changes in multiple joints simultaneously. This systematic review summarizes the imaging markers used for single photon emission computed tomography (SPECT) and/or positron emission tomography (PET) approaches, targeting pathways and mediators involved in synovial neo-angiogenesis in RA.

VEGF Profile in Early Undifferentiated Arthritis Cohort

Background and Objectives: Early undifferentiated arthritis (UA) is a group of inflammatory joint diseases that are not classified under any specific rheumatic or connective tissue disorder and might evolve into chronic inflammatory arthritis or may be a self-limiting condition. Early recognition and treatment are crucial for the future course of the disease. Vascular endothelial growth factor (VEGF) is an angiogenic regulator that induces the growth of new capillary blood vessels, which are important in joint invasion and destruction during the progression of chronic inflammatory arthritis. The aim of this study was to assess VEGF levels associated with sociodemographic, clinical, laboratory, and ultrasound findings in the early UA patient cohort as well as to evaluate VEGF as a potential prognostic marker for arthritis outcomes. Materials and Methods: Seventy-six patients with inflammatory arthritis in at least one joint, with a duration of arthritis <12 months at the study entry that did not meet any rheumatic disease classification criteria, were enrolled after informed consent was obtained. Patient’s sociodemographic, laboratory data, and clinical disease characteristics were recorded, VEGF levels were measured, and ultrasound (US) of tender and swollen joints was performed. Results: VEGF levels had positive correlation with conventional rheumatic disease activity and diagnostic markers: erythrocyte sedimentation rate (ESR), C−reactive protein (CRP), and rheumatoid factor (RF) (p < 0.05). RF-positive patients had higher VEGF values (p = 0.024). A statistically higher number of patients whose VEGF levels were below the median value presented with active infection (p = 0.046). In patients with a higher number of swollen joints, and a higher score of synovitis and power doppler (PD) seen on US, VEGF levels were statistically significantly higher. Patients who after 12-month follow-up developed rheumatoid arthritis (RA) had statistically higher VEGF levels at baseline compared with those who developed spondyloarthropathies (p = 0.028). Conclusions: This study demonstrated that VEGF levels significantly represented inflammatory processes that were present in the joints (number of swollen joints, synovitis, and PD changes) of the early UA cohort.

Cytokines and chemokines multiplex analysis in patients with low disease activity rheumatoid arthritis

Rheumatoid arthritis is a severe chronic autoimmune disorder that results from pathological activation of immune cells and altered cytokine/chemokine network. The aim of our study was to evaluate concentrations of chosen cytokines and chemokines in blood sera and synovial fluid samples isolated from low disease activity rheumatoid arthritis (RA) patients and osteoarthritis (OA) sufferers. Blood sera and synovial fluid samples have been obtained from 24 OA and 14 RA patients. Cytokines/chemokines levels have been determined using a Milliplex^® Map 38-plex human cytokine/chemokine magnetic bead-based panel (Merck Millipore, Germany) and Luminex^® MAGPIX^® platform (Luminex USA). Low disease activity RA patients showed altered concentration of numerous cytokine/chemokine when compared to OA controls—they were characterized by, inter alia, increased: eotaxin/CCL11 (p = 0.037), GRO/CXCL1 (p = 0.037), IL-2 (p = 0.013), IL-4 (p = 0.017), IL-7 (p = 0.003), IL-8 (p = 0.0007) and GM-CSF (p = 0.037) serum levels, whilst MDC/CCL22 concentration was decreased in this group (p = 0.034). Eotaxin/CCL11 (p = 0.001), GRO/CXCL1 (p = 0.041), IL-10 (p = 0.003), GM-CSF (p = 0.01), IL-1RA (p = 0.0005) and VEGF (p = 0.01) concentrations in synovial fluid of RA females were also increased. Even with low disease activity score, RA patients exhibited increased concentrations of cytokines with pro- and anti-inflammatory activities, as well as numerous chemokines, growth factors and regulators of angiogenesis. Surprisingly, RA subjects also shown decreased concentration of CCL22 chemokine. The attempt to restore cytokine balance and tolerogenic environment is ineffective in RA sufferers even with good disease management. Distinguished factors could serve as possible indicators of disease progression even in low disease activity patients.

Ex vivo exposure to different types of graphene-based nanomaterials consistently alters human blood secretome

The biomedical applications of graphene-based nanomaterials (GBN) have significantly grown in the last years. Many of these applications suppose their intravenous exposure and, in this way, GBN could encounter blood cells triggering an immunological response of unknown effects. Consequently, understanding the relationships between GBN and the immune system response should be a prerequisite for its adequate use in biomedicine. In the present study, we have conducted a little explored ex vivo exposure method in order to study the complexity of the secretome given by the interactions between GBN and blood cells. Blood samples from different healthy donors were exposed to three different types of GBN widely used in the biomedical field. In this sense, graphene oxide (GO), graphene nanoplatelets (GNPs), graphene nanoribbons (GNRs) and a panel of 105 proteins representatives of the blood secretome were evaluated. The results show broad changes in both the cytokines number and the expression levels, with important changes in inflammatory response markers. Furthermore, the indirect soft-agar assay was used as a tool to unravel the global functional impact of the found secretome changes. Our results indicate that the GBN-induced altered secretome can modify the natural anchorage-independent growth capacity of HeLa cells, used as a model. As a conclusion, this study describes an innovative approach to study the potential harmful effects of GBN, providing relevant data to be considered in the biomedical context when GBN are planned to be used in patients.

Comprehensive evaluation on anti-inflammatory and anti-angiogenic activities in vitro of fourteen flavonoids from Daphne Genkwa based on the combination of efficacy coefficient method and principal component analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Genkwa flos, as a traditional herb, is the dried flower buds of Daphne genkwa Sieb.et Zucc. It is used in traditional medicine for the treatment of cough, sore throats, edema.

AIM OF THE STUDY

The study aimed to explore a new mathematical method for multivariate evaluation, investigate the anti-inflammatory and anti-angiogenic activities of flavonoids in Daphne Genkwa under ex vivo conditions.

MATERIALS AND METHODS

The flavonoids monomers in Daphne Genkwa were separated by preparative liquid chromatography and identified by HPLC-ESI-ITMS. An in vitro inflammatory model of macrophage RAW264.7 induced by LPS and an angiogenesis model of human umbilical vein endothelial cells induced by TNF-α were established. Flavonoids were extracted and prepared for intervention to detect the amount of secretion after drug intervention to reflect the anti-inflammatory and anti-angiogenic activities of each component. In addition, a new mathematical method, which combined principal component analysis and efficacy coefficient method, was adopted in pharmacodynamic evaluation.

RESULTS

Fourteen flavonoids monomers were separated by preparative liquid chromatography and identified by HPLC-ESI-ITMS including H1 (hydroxygenkwanin-5-O-β-D-glucoside), H2 (apigenin-7-O-β-D-glucoside), H3 (kaempferol-3-O-β-D-glucoside), H4 (hydroxygenkwanin-5-O-β-D-primeveroside), H5 (apigenin-5-O-β-D-primeveroside), H6 (apigenin-7-O-β-D-glucuronide), H7 (luteolin-5-O-β-D-glucopyranoside), H8 (genkwain-5-O-β-D- glucoside), H9 (luteolin), H10 (Daphnodorin G), H11 (tiliroside), H12 (apigenin), H13 (3'- hydroxygenkwain) and H14 (genkwanin). We found that most of flavonoids down-regulated VCAM and MMP-3, while H1, H8, H9, H14 reduced VEGF and ICAM was only decreased by H14.

CONCLUSION

Genkwanin may be the most active anti-rheumatoid arthritis flavonoids in Daphne genkwa. Meanwhile, the new mathematical method used in the study provided a new direction for solving the problem of multi-index pharmacodynamic evaluation.

Relationship between the higher inflammatory cytokines level in the aqueous humor of Fuchs uveitis syndrome and the presence of cataract

BACKGROUND

This study aims to compare the levels of intraocular cytokines between Fuchs uveitis syndrome (FUS) eyes and the senile cataract eyes. The association between inflammatory cytokine levels and cataract severity in FUS is evaluated to find the possible mechanism of cataract in FUS eyes.

METHODS

A retrospective study of 28 eyes with FUS was performed. Auxiliary examinations were performed, including ophthalmic examinations, laser flare-cell photometry, and levels of inflammatory cytokines in the aqueous humor were measured. The control group included 25 eyes with senile cataract. Data on the aqueous humor inflammatory cytokines were compared between the two groups. The association between the aqueous humor cytokine levels and severity of posterior subcapsular cataract was assessed.

RESULTS

There were 28 eyes with FUS in 27 patients. Unilateral involvement was noted in 26 patients (96.30%). Stellate keratic precipitates (KPs) were noted in 16 eyes (57.14%). Heterochromia was observed in 21.43% of affected eyes. Posterior subcapsular cataract (PSC) was observed in 16 of the 28 eyes. Eyes with FUS had significantly higher aqueous humor (AH) cytokine levels (VEGF, bFGF, IL-6, IL-8 and IL-10) compared with the control eyes (P < 0.05). There was a statistically significant positive correlation between the severity of cataract and IL-6 and IL-8 levels in the AH (τ = 0.664 and 0.634, respectively; P = 0.001, P = 0.002, respectively).

CONCLUSIONS

Expression of VEGF, bFGF, IL-6, IL-8 and IL-10 in the AH of FUS patients was significantly higher than in senile cataract eyes, and the aqueous humor levels of IL-6 and IL-8 were significantly positively associated with the severity of posterior subcapsular cataract. Our results imply that an inflammation mechanism may be involved in the early development of cataract in FUS.

The Relationship Between Serum Angiogenic Factor Levels and Disease Activity in Rheumatoid Arthritis

Objectives

This study aims to evaluate the relationship between serum angiogenic factor levels and disease activity in patients with rheumatoid arthritis (RA) using both clinical and dynamic wrist magnetic resonance imaging (MRI) data.

Patients and methods

Simultaneous serum angiogenesis markers [vascular endothelial growth factor (VEGF), angiopoietin-1 (ANG1), ANG2, and tyrosine-protein kinase receptor for angiopoietin (Tie-2)] were studied in 40 patients with RA (13 males, 27 females; mean age 51.1±10.8 years; range, 23 to 69 years) and 20 healthy controls (11 males, 9 females; mean age 47.3±12.8 years; range, 29 to 69 years) and dynamic contrast-enhanced wrist MRI was performed in 40 RA patients and seven controls. Rate of early in 55th second (REE) and Relative enhancement (REt) values were calculated from the signal time curve values obtained from the analysis of images. In clinical assessment, duration of morning stiffness, patient pain assessment [visual analog scale (VAS)], physician and patient global assessments (VAS) were recorded. The number of tender joints and swollen joints were determined. Disease activity score 28 and Ritchie scores were calculated. Health assessment questionnaire was used for functional evaluation. Anti-cyclic citrullinated peptide, rheumatoid factor, erythrocyte sedimentation rate and high sensitive C-reactive protein analyses were performed.

Results

Serum VEGF, REE and REt values were significantly higher in RA patients than healthy controls (p=0.002, p=0.00, p=0.00, respectively). There was no significant correlation between serum angiogenesis markers and clinical parameters or REE and REt (p>0.05). VEGF value correlated positively with disease duration (p=0.024).

Conclusion

Serum VEGF was higher in RA patients. While its level was associated with disease duration, no significant correlation was found with disease activity. As a diagnostic test, dynamic contrast-enhanced MRI was a valuable method for showing disease activity.

Comparison of therapeutic efficacy and mechanism of paclitaxel alone or in combination with methotrexate in a collagen-induced arthritis rat model

OBJECTIVE

To compare the therapeutic efficacy of paclitaxel (PTX) alone to its combination with methotrexate (MTX) on rheumatoid arthritis.

METHODS

A collagen-induced arthritis (CIA) rat model was established by induction of type II collagen. Rats were divided into blank control group, CIA model group, MTX group 1 mg/kg, PTX 1.5 mg/kg, PTX 2.5 mg/kg, PTX 3.5 mg/kg, and MTX 1 mg/kg + PTX 3.5 mg/kg, with 10 rats per group. The inflammation of the ankle joint was analyzed by H&E staining and interleukin (IL)-1β and IL‑6 expression was detected by immunohistochemistry. TUNEL assay was performed to detect synovial tissue cell apoptosis after administration of PTX and MTX either alone or in combination. TLR4 and p‑NF-κBp65 protein expression in synovial tissue and the changes of serum IL‑1β, IL‑6, IL‑12, MMP‑3, and TNFα protein factors were detected by western blot and ELISA, respectively.

RESULTS

PTX and MTX improved histopathological changes in CIA rats. Besides, the apoptosis rate of synovial tissue cells in the PTX 3.5 mg/kg group was more than that of the PTX + MTX group. Immunohistochemistry and western blot results indicated that PTX and MTX reduce the expression rate of IL‑6 and IL‑1β and downregulate TLR4 and p‑NF-κBp65 protein expression. Furthermore, TLR4 and p‑NF-κBp65 reduced the concentration of MMP‑3, IL‑12, IL‑6, IL1‑β, and TNFα.

CONCLUSION

Both PTX and MTX exert significant suppression on rheumatoid arthritis, and the combined effect of the two drugs is weaker than that of PTX alone. Moreover, intraperitoneal injection of PTX 3.5 mg/kg every other day was the optimal dose observed in this study.

Angiogenic cytokines can reflect the synovitis severity and treatment response to biologics in rheumatoid arthritis

Angiogenesis and synoviocyte hyperplasia, called 'pannus,' are pathologic hallmarks of rheumatoid arthritis (RA). To determine the clinical significance of angiogenic cytokines in RA, the levels of pro-angiogenic cytokines, including VEGF, placenta growth factor (PlGF), and IL-6, were measured in the synovial fluid (SF, n = 54) and sera of RA patients (n = 157) using ELISA. Patients (n = 103) with disease activity score 28 (DAS28) > 3.2, which indicates moderate to high RA activity, underwent follow-up blood sampling at 6 months after treatment with conventional disease-modifying anti-rheumatic drugs (c-DMARD) or biologic DMARD (b-DMARD) including an anti-TNFα antibody, an anti-IL-6 antibody, and abatacept. Ultrasonography (US) was performed on affected joints to define the synovitis severity at the time of sampling. Consequently, in the SF of RA patients, PlGF and IL-6 levels correlated well with synovitis severity determined by US. In RA sera, VEGF and IL-6 levels were elevated in proportion to synovitis severity, correlating with conventional markers for disease activity, including ESR, CRP, and DAS28. In c-DMARD users (n = 53), serially monitored levels of serum VEGF, IL-6, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) all decreased in good and moderate responders but not in nonresponders. In b-DMARD users (n = 49), only serum VEGF well represented the treatment response, while CRP nonspecifically decreased irrespective of the treatment outcome. By multivariable analysis, serum ΔVEGF, but not ΔESR or ΔCRP, was an independent factor associated with good and moderate responses to DMARD. In summary, the angiogenic cytokines PlGF and VEGF represent the synovitis severity of RA assessed by US. In patients receiving b-DMARD, serum VEGF may be more valuable than CRP in reflecting the treatment response.

Preeclampsia as predisposing factor for hypertensive retinopathy: Participation by the RAAS and angiogenic factors

Preeclampsia (PE) is a hypertensive complication of pregnancy. Its cause is still unknown and it could be a risk factor for future ophthalmic problems. Retinal vascular bed alterations have been described as a consequence of PE, suggesting a retinopathy. Factors related to angiogenesis and vascular permeability, such as vascular endothelial growth factor (VEGF) and pigment epithelium derived factor (PEDF) or components of the renin angiotensin aldosterone system (RAAS), prorrenin/renin receptor ((P)RR) and angiotensin II type I receptor (AT1R) have been located in the retina, participating in other retinopathies, but it is unknown if they could participate in PE. Our aim was to elucidate whether VEGF, PEDF, (P)RR and AT1R could be modified during PE and during hypertension induced in rats with a history of PE. We used female Wistar rats and subrrenal aortic coarctation to induce PE, and after delivery, we induced a second hit by Nω-nitro-L-arginine methyl ester (L-NAME) administration. We measured blood pressure, proteinuria and pups development. In both models, eye fundal exploration and immunoblot for VEGF, PEDF, (P)RR and AT1R were performed. We found that the development of hypertension occurred faster in previously PE rats than in normal animals. VEGF, PEDF, (P)RR and AT1R were increased in PE, but in L-NAME-induced hypertension only (P)RR and AT1R were altered. Eye fundal data indicated that PE induced a level I retinopathy, but L-NAME induced a faster and more severe retinopathy in previously PE animals compared to previously normal pregnancy rats. These results indicate that PE predisposes to development of a faster and more severe retinopathy after a second hit. They also suggest that VEGF and PEDF seem to participate only in PE retinopathy, but in both models, RAAS components seem to have a more critical participation.

Dysregulated miR-125a promotes angiogenesis through enhanced glycolysis

Background

Although neoangiogenesis is a hallmark of chronic inflammatory diseases such as inflammatory arthritis and many cancers, therapeutic agents targeting the vasculature remain elusive. Here we identified miR-125a as an important regulator of angiogenesis.

Methods

MiRNA levels were quantified in Psoriatic Arthritis (PsA) synovial-tissue by RT-PCR and compared to macroscopic synovial vascularity. HMVEC were transfected with anti-miR-125a and angiogenic mechanisms quantified using tube formation assays, transwell invasion chambers, wound repair, RT-PCR and western blot. Real-time analysis of EC metabolism was assessed using the XF-24 Extracellular-Flux Analyzer. Synovial expression of metabolic markers was assessed by immunohistochemistry and immunofluorescent staining. MiR-125a CRISPR/Cas9-based knock-out zebrafish were generated and vascular development assessed. Finally, glycolytic blockade using 3PO, which inhibits Phosphofructokinase-fructose-2,6-bisphophatase 3 (PFKFB3), was assessed in miR-125a−/− ECs and zebrafish embryos.

Findings

MiR-125a is significantly decreased in PsA synovium and inversely associated with macroscopic vascularity. In-vivo, CRISPR/cas9 miR-125a^−/− zebrafish displayed a hyper-branching phenotype. In-vitro, miR-125a inhibition promoted EC tube formation, branching, migration and invasion, effects paralleled by a shift in their metabolic profile towards glycolysis. This metabolic shift was also observed in the PsA synovial vasculature where increased expression of glucose transporter 1 (GLUT1), PFKFB3 and Pyruvate kinase muscle isozyme M2 (PKM2) were demonstrated. Finally, blockade of PFKFB3 significantly inhibited anti-miR-125a-induced angiogenic mechanisms in-vitro, paralleled by normalisation of vascular development of CRISPR/cas9 miR-125a^−/− zebrafish embryos.

Intepretation

Our results provide evidence that miR-125a deficiency enhances angiogenic processes through metabolic reprogramming of endothelial cells.

Fund

Irish Research Council, Arthritis Ireland, EU Seventh Framework Programme (612218/3D-NET).

KDR (VEGFR2) Genetic Variants and Serum Levels in Patients with Rheumatoid Arthritis

We investigated kinase insert domain-containing receptor (KDR) polymorphisms and protein levels in relation to susceptibility to and severity of Rheumatoid Arthritis (RA). 641 RA patients and 340 controls (HC) were examined for the rs1870377 KDR variant by the polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method and for rs2305948 and rs2071559 KDR single nucleotide polymorphisms (SNPs) by TaqMan SNP genotyping assay. KDR serum levels were determined by enzyme-linked immunosorbent assay (ELISA). The rs1870377 KDR variant has shown association with RA under the codominant (p = 0.02, OR = 1.76, 95% CI = 1.09–2.85) and recessive models (p = 0.019, OR = 1.53, 95% CI = 1.07–2.20). KDR rs2305948 was associated with RA under the dominant model (p = 0.005, OR = 1.38, 95% CI = 1.10–1.73). Under the codominant model, the frequency of the rs2071559 TC and GG genotypes were lower in RA patients than in controls (p < 0.001, OR = 0.51, 95% CI = 0.37–0.69, and p = 0.002, OR = 0.57, 95% CI = 0.39–0.81). KDR rs2071559 T and rs2305948 A alleles were associated with RA (p = 0.001, OR = 0.60, 95% CI = 0.45–0.81 and p = 0.008, OR = 1.71, CI = 1.15–2.54). KDR rs2305948SNP was associated with Disease Activity Score (DAS)-28 score (p < 0.001), Visual Analog Scale (VAS) score (p < 0.001), number of swollen joints (p < 0.001), mean value of CRP (p < 0.001). A higher KDR serum level was found in RA patients than in HC (8018 pg/mL versus 7381 pg/mL, p = 0.002). Present results shed light on the role of KDR genetic variants in the severity of RA.

Aqueous humor IL-8, IL-10, and VEGF levels in Fuchs' uveitis syndrome and Behçet's uveitis

PURPOSE

This study investigated the levels of interleukin (IL)-8, IL-10, and vascular endothelial growth factor (VEGF) in the aqueous humor (AqH) of patients with Behçet's uveitis (BU) and Fuchs' uveitis syndrome (FUS) during an inactive period and compared these levels with those in the AqH of noninflammatory healthy control subjects.

METHODS

This prospective and case-control study included 33 patients (16 patients with BU and 17 patients with FUS) and 35 control subjects. IL-8, IL-10, and VEGF levels in the AqH were quantified by performing sandwich enzyme-linked immunosorbent assay. Kruskal-Wallis test was used to compare the cytokine levels in the different groups, and statistical significance was set at p < 0.05.

RESULTS

IL-8 levels were significantly higher in the AqH of patients with BU and FUS than in the AqH of control subjects (p < 0.001 and p < 0.001, respectively). IL-10 levels were significantly lower in the AqH of patients with BU than in the AqH of patients with FUS and of control subjects (p = 0.001 and p < 0.001, respectively). Although VEGF levels were higher in the AqH of patients with FUS than in the AqH of patients with BU and of control subjects, the difference was significant only between patients with FUS and control subjects (p < 0.001).

CONCLUSIONS

We observed a significant decrease in IL-10 levels in the AqH of patients with BU and a significant increase in VEGF levels in the AqH of patients with FUS compared to controls. IL-8 and VEGF levels showed no significant difference among uveitis patients.

A fresh look at angiogenesis in juvenile idiopathic arthritis

Angiogenesis is the complex process of creating new capillaries from preexisting blood vessels due to hypoxemia, injury or inflammation of the tissues. Numerous cytokines and cell mediators have been identified to induce and stimulate angiogenesis, but vascular endothelial growth factor (VEGF) is a key regulator. The role of proangiogenic factors in the pathogenesis of chronic arthritis is currently a subject of intensive investigations in adult patients with rheumatoid arthritis (RA) and, to a limited extent, in children with juvenile idiopathic arthritis (JIA). Recent studies has shown a significant correlation between proangiogenic marker concentrations and the severity of inflammation in either RA or JIA patients. The serum neovascularization markers correlate with the power Doppler ultrasound image of the inflamed joint and hypertrophic synovium, which may be connected with the disease activity.

The aim of this paper is to describe the state of the art on the important role of angiogenesis in adult and childhood rheumatoid arthritis.

Emerging role of semaphorin-3A in autoimmune diseases

Autoimmune diseases (ADs) are featured by the body's immune responses being directed against its own tissues, resulting in prolonged inflammation and subsequent tissue damage. Currently, the exact pathogenesis of ADs remains not fully elucidated. Semaphorin-3A (Sema3A), a secreted member of semaphorin family, is a potent immunoregulator during all immune response stages. Sema3A has wide expression, such as in bone, connective tissue, kidney, neurons, and cartilage. Sema3A can downregulate ADs by suppressing the over-activity of both T-cell and B-cell autoimmunity. Moreover, Sema3A shows the ability to enhance T-cell and B-cell regulatory properties that control ADs, including systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, and systemic sclerosis. However, it can also induce ADs when overexpressed. Together, these data strongly suggest that Sema3A plays a pivotal role in ADs, and it may be a promising treatment target for these diseases. In the present review, we focus on the immunological functions of Sema3A and summarize recent studies on the involvement of Sema3A in the pathogenesis of ADs; the discoveries obtained from recent findings may translate into novel therapeutic agent for ADs.

Circulating serum interleukin-6, serum chitinase-3-like protein-1, and plasma vascular endothelial growth factor are not predictive for remission and radiographic progression in patients with early rheumatoid arthritis: post-hoc explorative and validation studies based on the CIMESTRA and OPERA trials

OBJECTIVE

To investigate serum interleukin-6 (IL-6), serum chitinase-3-like protein-1 (YKL-40), and plasma vascular endothelial growth factor (VEGF) as measures of disease activity and predictors of clinical remission and radiographic progression in two early rheumatoid arthritis (RA) randomized controlled trials (RCTs).

METHOD

Treatment-naïve patients with early RA (< 6 months' duration) and active disease, participating in two investigator-initiated RCTs, were treated according to a predefined treat-to-target algorithm aiming at inflammatory control, using methotrexate (MTX) + cyclosporine versus MTX + placebo (CIMESTRA study, n = 150, 5 year follow-up) or MTX + adalimumab versus MTX + placebo (OPERA study, n = 180, 2 year follow-up). The 28-joint Disease Activity Score (DAS28) and conventional radiography [bilateral hands and feet at baseline, 2 years and 5 years (only CIMESTRA)] were obtained at baseline and during follow-up. Serum IL-6, serum YKL-40, and plasma VEGF were measured in baseline blood samples and during follow-up. Hypotheses regarding the biomarkers' relation with DAS28 and ability to predict clinical remission (DAS28 < 2.6) and radiographic progression (change in total Sharp van der Heijde score ≥ 2) were generated in CIMESTRA and validated in OPERA, by Spearman's correlation and logistic regression analyses.

RESULTS

Baseline IL-6, YKL-40, and VEGF correlated significantly with DAS28 in CIMESTRA (r = 0.50, r = 0.36, r = 0.36, respectively, all p < 0.01) and these results were confirmed in OPERA patients (r = 0.52, p < 0.01; r = 0.18, p = 0.01; r = 0.23, p = 0.002, respectively). None of the biomarkers (absolute values or change) was predictive of clinical remission or radiographic progression at 2 or 5 years in either study.

CONCLUSION

Serum IL-6, serum YKL-40, and plasma VEGF were significantly correlated with DAS28 at baseline, but did not have consistent predictive value for clinical remission or radiographic progression in two early RA RCTs.

LPS‑induced downregulation of microRNA‑204/211 upregulates and stabilizes Angiopoietin‑1 mRNA in EA.hy926 endothelial cells

Angiopoietin-1 (ANG-1), a ligand of the endothelial cell-specific TIE2 surface receptor, acts in a complementary and coordinated manner with vascular endothelial growth factor during the process of angiogenesis. ANG-1 can be used as a clinically informative biomarker of disease severity and outcome in severe sepsis. The epithelium-specific Ets transcription factor 1 can activate ANG-1 transcription in the setting of inflammation; however, relatively little is known about the regulation of ANG-1 by microRNAs (miRs). It was observed that lipopolysaccharide (LPS) significantly increased ANG-1 mRNA and protein expression in EA.hy926 cells. ANG-1 was identified as a potential target gene of miR-204 and miR-211. Overexpression of miR-204/211 partially reversed the LPS-induced ANG-1 expression in EA.hy926 cells. Furthermore, overexpression of miR-204/211 significantly reduced the activity of a luciferase reporter gene containing the wild-type ANG-1 3′-untranslated region (UTR), but did not influence the activity of a luciferase reporter gene containing the ANG-1 3′-UTR with a mutated miR-204/211 binding site, confirming that miR-204/211 can bind to the ANG-1 3′-UTR and post-transcriptionally regulate ANG-1. Additionally, LPS enhanced the stability of ANG-1 mRNA by reducing the abundance of miR-204/211. Overexpression of miR-204/211 reduced the migration of EA.hy926 cells in vitro. The present study demonstrated that ANG-1 is a novel direct target gene of miR-204 and miR-211; in addition, LPS was able to inhibit this effect by reducing the expression of miR-204 and miR-211.

Taxol alleviates collagen-induced arthritis in mice by inhibiting the formation of microvessels

The objective of the present study is to evaluate the inhibitory effects of taxol (PTX) on angiogenesis in a collagen-induced arthritis (CIA) mouse model. Collagen II (C II) and complete Freund’s adjuvant (CFA) were used in C57BL/6 (H-2b) mice to generate the CIA model. Random grouping was performed in the normal control group, CIA model group, PTX 1.5 mg/kg group, PTX 1.0 mg/kg group, and PTX 0.5 mg/kg group. Arthritis index scores, tissue pathology scores, and synovium microvessel density (MVD) analysis were performed. Immunohistochemistry and enzyme-linked immunosorbent assay were used to detect the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-α (HIF-1α). The correlation between MVD and pathological scores and between MVD and the expression of VEGF as well as HIF-1α in the synovium were also evaluated. After PTX treatment, the three intervention group arthritis index scores were reduced when compared with the CIA group. The total histological scores in the three PTX treatment groups were lower than those in the CIA group. Similarly, PTX significantly alleviated the scores for synovitis, pannus formation, and bone destruction. Compared with the CIA group, the MVD of the three intervention groups decreased in a dose-dependent manner. The expression of VEGF and HIF-1α in synovial tissues and serum also significantly decreased after PTX treatment. Further analysis showed that MVD and pathological scores and MVD and expression of VEGF as well as HIF-1α in the synovium were positively correlated. PTX may alleviate CIA by suppressing angiogenesis, providing new insights into the treatment of rheumatoid arthritis (RA). VEGF and HIF-1α may be targets for PTX suppression of microvessel formation.

Relationship between VEGF Gene Polymorphisms and Serum VEGF Protein Levels in Patients with Rheumatoid Arthritis

BACKGROUND

Rheumatoid arthritis (RA) is one of the chronic autoimmune diseases, with genetic and environmental predisposition, and synovial angiogenesis is considered to be a notable stage in its pathogenesis. Angiogenesis or vascular proliferation has been suggested to be a pivotal mechanism involved in both inflammation/immune activation and joint invasion and destruction. RA may be considered an "angiogenic disease" because it is associated with active tissue neovascularization. Vascular endothelial growth factor (VEGF) promotes vascular permeability, regulates angiogenesis, endothelial cell proliferation and migration, chemotaxis, and capillary hyper permeability and therefore is involved in the development of inflammation. VEGF is the most potent proangiogenic molecule promoting the angiogenic phenotype of RA and is upregulated in RA.

OBJECTIVES

The aim of the study was to identify functional VEGF variants and their possible association with VEGF expression, susceptibility to and severity of RA.

METHODS

581 RA patients and of 341 healthy individuals were examined for -1154 A/G, -2578 A/C VEGF gene polymorphisms by PCR-RFLP method and for -634 G/C VEGF gene polymorphisms by TaqMan SNP genotyping assay. Serum VEGF levels in RA patients and controls were measured by ELISA.

RESULTS

The -1154 A/G VEGF gene polymorphism under the codominant, recessive (AA+AG vs. GG) and dominant (AA vs. AG+GG) models were associated with RA (p = 0.0009; p = 0.004; p = 0.017, respectively). VEGF -2578 A/C revealed differences in the case-control distribution in codominant, recessive, dominant and overdominant models (all p<0.0001). Furthermore, the -634 G/C VEGF gene SNP was not correlated with susceptibility to RA in Polish population. The genotype-phenotype analysis showed significant association between the VEGF -1154 A/G and -634 G/C and mean value of the hemoglobin (all p = 0.05), additionally they relevated that the number of women with the polymorphic allele -2578 C was lower than the number of women with wild type allele -2578A (p = 0.006). Serum VEGF levels were significantly higher in RA patients than in control groups (both p = 0,0001).

CONCLUSION

Present findings indicated that VEGF genetic polymorphism as well as VEGF protein levels may be associated with the susceptibility to RA in the Polish population.

Generation and characterization of a human nanobody against VEGFR-2

AIM

Nanobody is an antibody fragment consisting of a single monomeric variable antibody domain, which can be used for a variety of biotechnological and therapeutic purposes. The aim of this work was to isolate and characterize a human signal domain antibody against VEGFR-2 domain3 (VEGFR D3) from a phage display library.

METHODS

To produce antigen-specific recombinant nanobodies with high affinity to VEGFR2 D3, a liquid phase panning strategy was used for all rounds of panning. For nanobody expression and purification, four VEGFR2 D3-blocking clones were subcloned into a pETduet-biotin-MBP expression vector. The recombinant proteins carried an MBP tag to facilitate purification by affinity chromatography. Recombinant NTV(1-4) was obtained after an additional gel filtration chromatography step. The interactions between VEGFR2 D3 and NTV(1-4) were assessed with luminescence-based AlphaScreen assay and SPR assay. Anti-angiogenesis effects were examined in human umbilical vein endothelial cells (HUVECs).

RESULTS

In the AlphaScreen assay, NTV1 (100 and 200 nmol/L) elicited the highest binding signal with VEGFR2 D3; NTV2 showed moderate interactions with VEGFR2 D3; NTV3 and NTV4 exhibited little or no interaction with VEGFR2 D3. In the SPR assay, NTV1 displayed a high affinity for VEGFR2 D3 with an equilibrium dissociation constant (KD) of 49±1.8 nmol/L. NTV1 (1-1000 nmol/L) dose-dependently inhibited the proliferation of HUVECs and the endothelial tube formation by the HUVECs.

CONCLUSION

The nanobody NTV1 is a potential therapeutic candidate for blocking VEGFR2. This study provides a novel and promising strategy for development of VEGFR2-targeted nanobody-based cancer therapeutics.

Endothelial Dysfunction and Inflammation: Immunity in Rheumatoid Arthritis

Inflammation, as a feature of rheumatoid arthritis (RA), leads to the activation of endothelial cells (ECs). Activated ECs induce atherosclerosis through an increased expression of leukocyte adhesion molecules. Endothelial dysfunction (ED) is recognized as a failure of endothelial repair mechanisms. It is also an early preclinical marker of atherosclerosis and is commonly found in RA patients. RA is now established as an independent cardiovascular risk factor, while mechanistic determinants of ED in RA are still poorly understood. An expanding body of study has shown that EC at a site of RA is both active participant and regulator of inflammatory process. Over the last decade, a role for endothelial dysfunction in RA associated with cardiovascular disease (CVD) has been hypothesized. At the same time, several maintenance drugs targeting this phenomenon have been tested, which has promising results. Assessment of endothelial function may be a useful tool to identify and monitor RA patients.

Angiogenic factors, bladder neuroplasticity and interstitial cystitis-new pathobiological insights

Vascular endothelial growth factor (VEGF) is essential for normal embryonic development, and maintenance of adult vascular function. Originally described as a vascular permeability factor, VEGF alters tight cell junctions and contributes to maintenance of bladder permeability. VEGF and its receptors are not only expressed in bladder blood vessels but also in apical cells and intramural ganglia. VEGF receptors are fundamentally altered by inflammation and bladder diseases such as interstitial cystitis (IC). Experimental results indicate that VEGF exerts direct effects on bladder nerve density and function. Regardless of the etiology or initiating cause for IC, it is hypothesized that the urinary bladder responds to injury by increasing the production of VEGF that acts initially as a survival mechanism. However, VEGF also has the capacity to increase vascular permeability leading to glomerulations, edema, and inflammation. Moreover, due to elevated numbers of VEGF receptors in the urothelium, the increased levels of VEGF further increase bladder permeability and establish a vicioCus cycle of disease pathophysiology.

Pristimerin inhibits angiogenesis in adjuvant-induced arthritic rats by suppressing VEGFR2 signaling pathways

Rheumatoid arthritis (RA) is a progressive, inflammatory autoimmune disease. As RA progresses, the hyperplastic synovial pannus creates a hypoxic, inflammatory environment that induces angiogenesis. Further vascularization of the synovial tissue promotes pannus growth and continued infiltration of inflammatory leukocytes, thus perpetuating the disease. Pristimerin inhibits inflammation and tumor angiogenesis. The present study focused on the inhibition of angiogenesis by Pristimerin in adjuvant-induced arthritic rats and the underlying molecular mechanisms. Our results clearly demonstrate for the first time that Pristimerin significantly reduces vessel density in synovial membrane tissues of inflamed joints and reduces the expression of pro-angiogenic factors in sera, including TNF-α, Ang-1, and MMP-9. Pristimerin also decreased the expression of VEGF and p-VEGFR2 in the synovial membrane, whereas the total amount of VEGFR2 remained unchanged. Pristimerin suppressed the sprouting vessels of the aortic ring and inhibited VEGF-induced HFLS-RA migration in vitro. Pristimerin also inhibited VEGF-induced proliferation, migration and tube formation by HUVECs, blocked the autophosphorylation of VEGF-induced VEGFR2 and consequently downregulated the signaling pathways of activated PI3K, AKT, mTOR, ERK1/2, JNK, and p38 in VEGF-induced HUVECs. Our results indicate that Pristimerin suppressed synovial angiogenesis in our rat model and in vitro by interrupting the targeting of VEGFR2 activation. Therefore, Pristimerin has potential as an angiogenesis inhibitor in the treatment of rheumatoid arthritis.

Early biomarkers of joint damage in rheumatoid and psoriatic arthritis

Joint destruction, as evidenced by radiographic findings, is a significant problem for patients suffering from rheumatoid arthritis and psoriatic arthritis. Inherently irreversible and frequently progressive, the process of joint damage begins at and even before the clinical onset of disease. However, rheumatoid and psoriatic arthropathies are heterogeneous in nature and not all patients progress to joint damage. It is therefore important to identify patients susceptible to joint destruction in order to initiate more aggressive treatment as soon as possible and thereby potentially prevent irreversible joint damage. At the same time, the high cost and potential side effects associated with aggressive treatment mean it is also important not to over treat patients and especially those who, even if left untreated, would not progress to joint destruction. It is therefore clear that a protein biomarker signature that could predict joint damage at an early stage would support more informed clinical decisions on the most appropriate treatment regimens for individual patients. Although many candidate biomarkers for rheumatoid and psoriatic arthritis have been reported in the literature, relatively few have reached clinical use and as a consequence the number of prognostic biomarkers used in rheumatology has remained relatively static for several years. It has become evident that a significant challenge in the transition of biomarker candidates to clinical diagnostic assays lies in the development of suitably robust biomarker assays, especially multiplexed assays, and their clinical validation in appropriate patient sample cohorts. Recent developments in mass spectrometry-based targeted quantitative protein measurements have transformed our ability to rapidly develop multiplexed protein biomarker assays. These advances are likely to have a significant impact on the validation of biomarkers in the future. In this review, we have comprehensively compiled a list of candidate biomarkers in rheumatoid and psoriatic arthritis, evaluated the evidence for their potential as biomarkers of bone (joint) damage, and outlined how mass spectrometry-based targeted and multiplexed measurement of candidate biomarker proteins is likely to accelerate their clinical validation and the development of clinical diagnostic tests.

Serum Angiogenesis Markers and Their Correlation with Ultrasound-Detected Synovitis in Juvenile Idiopathic Arthritis

Synovial angiogenesis is considered to be an important early step in the pathogenesis of juvenile idiopathic arthritis (JIA). In this study we assessed levels of angiogenic markers in serum or synovial fluid and their possible relevance to disease activity or degree of ultrasound signs of synovial inflammation and angiogenesis in early JIA. The concentration of vascular endothelial growth factor (VEGF), its soluble receptors 1 and 2 (sVEGF-R1, sVEGF-R2), and angiopoietins 1 and 2 (ANG-1, ANG-2) were evaluated in 43 JIA patients and 23 healthy controls. Synovial angiogenesis was assessed by means of Power-Doppler Ultrasonography (PDUS), according to the fourth-grade vascularity scale. VEGF and its receptors' (sVEGF-R1, sVEGF-R2) serum levels were significantly higher in JIA patients (p = 0.002). We found large variation in serum ANG-1 and ANG-2 levels. The PDUS imaging identified increased synovial microvascular blood flow in 15 (35.7%) examined JIA children. Intensity of joint vascularization correlated with higher serum VEGF and its levels was lowest in grade 0 and highest in grade 3 (p < 0.007 and p < 0.001, resp.). In conclusion, the high correlation between synovial microvascular blood flow, serum angiogenic proteins, and symptoms of synovitis may indicate its important role in pathogenesis of JIA.

Combustion smoke-induced inflammation in the cerebellum and hippocampus of adult rats

AIMS

The effect of combustion smoke inhalation on the respiratory system is widely reported but its effects on the central nervous system remain unclear. Here, we aimed to determine the effects of smoke inhalation on the cerebellum and hippocampus which are areas vulnerable to hypoxia injury.

METHODS

Adult male Sprague-Dawley rats were subjected to combustion smoke inhalation and sacrificed at 0.5, 3, 24 and 72 h after exposure. The cerebellum and hippocampus were subjected to Western analysis for VEGF, iNOS, eNOS, nNOS and AQP4 expression; ELISA analysis for cytokine and chemokine levels; and immunohistochemistry for GFAP/AQP4, RECA-1/RITC and TUNEL. Aminoguanidine (AG) was administered to determine the effects of iNOS after smoke inhalation.

RESULTS

Both the cerebellum and hippocampus showed a significant increase in VEGF, iNOS, eNOS, nNOS and AQP4 expression with corresponding increases in inflammatory cytokines and chemokines and increased AQP4 expression and RITC permeability after smoke exposure. AG was able to decrease the expression of iNOS, followed by VEGF, eNOS, nNOS, RITC and AQP4 after smoke exposure. There was also a significant increase in TUNEL+ cells in the cerebellum and hippocampus which were not significantly reduced by AG. Beam walk test revealed immediate deficits after smoke inhalation which was attenuated with AG.

CONCLUSION

The findings suggest that iNOS plays a major role in the central nervous system inflammatory pathophysiology after smoke inhalation exposure with concomitant increase in proinflammatory molecules, vascular permeability and oedema, for which the cerebellum appears to be more vulnerable to smoke exposure than the hippocampus.

Local synovial engagement of angiogenic TIE-2 is associated with the development of persistent erosive rheumatoid arthritis in patients with early arthritis

OBJECTIVE

To examine the role of vascular endothelial growth factor (VEGF) and angiopoietin signaling in the diagnosis and disease outcome of patients with early arthritis.

METHODS

Fifty patients with early arthritis (disease duration <1 year) who had not been treated with disease-modifying antirheumatic drugs (DMARDs) were monitored prospectively and were classified at baseline and after 2 years as having undifferentiated arthritis (UA), rheumatoid arthritis (RA), or spondyloarthritis (SpA). All patients underwent arthroscopic synovial biopsy at baseline. Synovial expression of VEGF, VEGF receptor, angiopoietin 1 (Ang-1), Ang-2, TIE-2, and activated p-TIE-2 was evaluated by immunohistochemistry. Serum levels of VEGF, Ang-1, and Ang-2 were measured by enzyme-linked immunosorbent assay. Secreted products of macrophages stimulated with Ang-1 and Ang-2 were measured using a multiplex system.

RESULTS

Expression of Ang-1 was comparable between the patients with RA at baseline and patients with UA who fulfilled the criteria for RA over time (UA/RA), and it was significantly higher in patients with RA (P < 0.05) or UA/RA (P < 0.005) than in patients with SpA. TIE-2 and p-TIE-2 were more highly expressed in patients with RA (P < 0.005) or UA/RA (P < 0.05) than in patients with SpA. Ang-1 significantly enhanced the tumor necrosis factor-dependent macrophage production of cytokines and chemokines that are known to be elevated in the synovial fluid of patients with early RA. In RA, relative TIE-2 activation predicted the development of erosive disease (R(2) = 0.35, P < 0.05).

CONCLUSION

Local engagement of synovial TIE-2 is observed during the earliest phases of RA, suggesting that TIE-2 signaling may contribute to disease development and progression or may indicate an attempt to protect against these processes. Early therapeutic targeting of TIE-2 signaling may be useful in improving outcome in arthritis.

Decreased semaphorin3A expression correlates with disease activity and histological features of rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is an autoimmune disease of which the pathogenetic mechanisms are not fully understood. Semaphorin3A (Sema3A) has an immune regulatory role. Neuropilin1 (NRP1), the primary receptor for Sema3A, is also a receptor for vascular endothelial growth factor 165 (VEGF₁₆₅). It has been shown that Sema3A competitively antagonizes VEGF165 signaling. This study investigated whether Sema3A is expressed in synovial tissues, and is associated with disease activity and the histological features of synovial tissues from RA patients.

Methods

Human synovial tissues samples were obtained from RA and osteoarthritis (OA) patients. Disease activity of RA patients was calculated using the 28-joint Disease Activity Score based on C-reactive protein (DAS28-CRP). The histological features of RA synovial tissues were evaluated using Rooney’s inflammation scoring system. The localization of Sema3A, VEGF₁₆₅ and NRP1 positive cells was immunohistochemically determined in synovial tissues. Expression levels of Sema3A, VEGF-A and NRP1 mRNA were determined using quantitative real-time polymerase chain reaction (qPCR).

Results

In OA specimens, Sema3A, VEGF₁₆₅ and NRP1 proteins were expressed in the synovial lining and inflammatory cells beneath the lining. Immunohistochemistry revealed the protein expression of Sema3A in synovial lining cells was decreased in RA tissues compared with OA samples. qPCR analysis demonstrated a significant reduction of Sema3A mRNA levels in RA synovial tissue samples than in OA and a significant correlation of the ratio of Sema3A/VEGF-A mRNA expression levels with DAS28-CRP (R = −0.449, p = 0.013). Sema3A mRNA levels also correlated with Rooney’s inflammation score, especially in perivascular infiltrates of lymphocytes (R = −0.506, p = 0.004), focal aggregates of lymphocytes (R = −0.501, p = 0.005) and diffuse infiltrates of lymphocytes (R = −0.536, p = 0.002).

Conclusions

Reduction of Sema3A expression in RA synovial tissues may contribute to pathogenesis of RA.

Expression of VEGF-receptors in TMJ synovium of rabbits with experimentally induced internal derangement

Our aim was to evaluate the expression of vascular endothelial growth factor receptors (VEGFRs) in the synovium of the temporomandibular joints (TMJ) of rabbits with experimentally induced internal derangement. Internal derangement was experimentally induced in 52 rabbit TMJ, and established on the right side of TMJ while the left side was used as the control. Each joint and its control was evaluated by magnetic resonance imaging (MRI) and endoscopy. The synovial tissues on both sides were harvested after one, two, three, and four weeks. The expression of VEGFRs mRNA was investigated in the experimental joint and its control using real-time polymerase chain reaction (PCR). Internal derangement was successfully confirmed in 45 of the 52 of the experimental joints (87%) on the right side by MRI and endoscopy. In the first and fourth week, the VEGFR-2 mRNA expression was higher in the experimental joints than in the controls (P=0.008 and P=0.02). Meanwhile, the VEGFR-1 mRNA expression was up-regulated in the experimental group compared with the controls during the fourth week (P=0.02). However, we found no significant differences in VEGFR-3 mRNA expression in the two groups during the first and fourth weeks. During the second and third weeks, the mRNA expression of the three receptors did not differ significantly among the groups. Our data have shown increased expression of VEGFR-1 and VEGFR-2 mRNA in the synovium of rabbit TMJ with internal derangement, which indicates that VEGFR-1 and VEGFR-2 may have important roles in the processes of internal derangement and formation of adhesions.

Angiopoietin-2 promotes inflammatory activation of human macrophages and is essential for murine experimental arthritis

BACKGROUND

Angiopoietin (Ang)-1 and Ang-2, and their shared receptor Tie2, are expressed in rheumatoid arthritis (RA) synovial tissue, but the cellular targets of Ang signalling and the relative contributions of Ang-1 and Ang-2 to arthritis are poorly understood.

OBJECTIVES

To determine the cellular targets of Ang signalling in RA synovial tissue, and the effects of Ang-2 neutralisation in murine collagen-induced arthritis (CIA).

METHODS

RA and psoriatic arthritis (PsA) synovial biopsies were examined for expression of Tie2 and activated phospho (p)-Tie2 by quantitative immunohistochemistry and immunofluorescent double staining. Human monocyte and macrophage Tie2 expression was determined by flow cytometry and quantitative PCR. Regulation of macrophage intracellular signalling pathways and gene expression were examined by immunoblotting and ELISA. CIA was assessed in mice treated with saline, control antibody, prednisolone or neutralising anti-Ang-2 antibody.

RESULTS

Expression of synovial Tie2 and p-Tie2 was similar in RA and PsA. Tie2 activation in RA patient synovial tissue was predominantly localised in synovial macrophages and was expressed by human macrophage. Ang-1 and Ang-2 stimulated activation of multiple intracellular signalling pathways, and cooperated with tumour necrosis factor to induce macrophage interleukin 6 and macrophage inflammatory protein 1α production. Ang-2 selectively suppressed macrophage thrombospondin-2 production. Ang-2 neutralisation significantly decreased disease severity, synovial inflammation, neo-vascularisation and joint destruction in established CIA.

CONCLUSIONS

The authors identify synovial macrophages as primary targets of Ang signalling in RA, and demonstrate that Ang-2 promotes the pro-inflammatory activation of human macrophages. Ang-2 makes requisite contributions to pathology in CIA, indicating that targeting Ang-2 may be of therapeutic benefit in the treatment of RA.

Relationship of ultrasonographic findings with synovial angiogenesis modulators in different forms of knee arthritides

Angiogenesis is controlled by a variety of angiogenesis stimulators and inhibitors. The increased power Doppler (PD) signals determined by ultrasonography is an indirect marker of synovial vascularity in arthritis. We aimed to investigate relationship between ultrasonographic findings and synovial angiogenesis modulators. Thirteen Behcet's disease (BD), 15 spondyloarthropathy, 21 rheumatoid arthritis (RA), and 15 osteoarthritis (OA) patients with knee arthritis were included. Cumulative effusion, synovial hypertrophy, and PD signal scores were calculated in arthritic joints. In synovial fluid samples, angiogenesis inhibitors (angiostatin, thrombospondin-1, and endostatin) and stimulators [bFGF (basic fibroblast growth factor), angiopoietin-1] were studied. The comparisons between groups were made by Kruskal-Wallis test, and correlation analysis was calculated with Pearson and Spearman tests. Effusion scores were significantly higher in inflammatory arthritis than in OA. Synovial hypertrophy scores were higher in RA and spondylarthritis than in OA and BD. PD scores were not different between the groups. Synovial angiostatin and bFGF levels were significantly higher in patients with inflammatory arthritis than in OA. Cumulative effusion scores were positively correlated with angiopoietin-1, angiostatin, and bFGF and negatively correlated with thrombospondin-1 levels. Synovial hypertrophy scores were positively correlated with angiostatin and bFGF levels and negatively correlated with thrombospondin-1. No correlation was found between PD scores and modulators of angiogenesis. In large joints like knee, detecting PD signals alone was not sufficient to assess the angiogenesis. However, cumulative activity scores were positively correlated with angiogenesis stimulators. Therefore, when investigating the angiogenesis, PD technique should be added to gray-scale examinations.

An observational study of endothelial function in early arthritis

BACKGROUND

Endothelial dysfunction is present in established rheumatoid arthritis, but it is not clear at what stage of the disease this abnormality develops. We set out to determine whether endothelial damage/dysfunction is present in a group of patients with early arthritis (EA) (new onset inflammatory arthritis, EA).

MATERIALS AND METHODS

Eighteen patients with EA, 48 healthy controls and 25 disease controls were recruited. Plasma was obtained for endothelial [von Willebrand factor (vWF) and soluble E-selectin] and angiogenesis markers (vascular endothelial growth factor and its receptor sFlt-1), adhesion molecules (intercellular adhesion molecule 1 and vascular cell adhesion molecule 1) and circulating endothelial cells (CECs, as a marker of endothelial damage). Microvascular endothelial function was assessed using laser Doppler perfusion imaging and macrovascular function using flow-mediated dilatation of the brachial artery.

RESULTS

von Willebrand factor and CECs (both P < 0.05) were significantly elevated in EA suggesting endothelial dysfunction and damage but were unrelated to classical laboratory markers of inflammation C-reactive protein, erythrocyte sedimentation rate or IL6. No other biomarkers was elevated in EA. Microvascular and macrovascular abnormalities were confined to endothelium-independent (smooth muscle cell) responses.

CONCLUSIONS

Endothelial damage/dysfunction is present early in the course of inflammatory arthritis but is not directly related to inflammation markers.

Development of a novel recombinant biotherapeutic with applications in targeted therapy of human arthritis

OBJECTIVE

To isolate recombinant antibodies with specificity for human arthritic synovium and to develop targeting reagents with joint-specific delivery capacity for therapeutic and/or diagnostic applications.

METHODS

In vivo single-chain Fv (scFv) antibody phage display screening using a human synovial xenograft model was used to isolate antibodies specific to the microvasculature of human arthritic synovium. Single-chain Fv antibody tissue-specific reactivity was assessed by immunostaining of synovial tissues from normal controls and from patients with rheumatoid arthritis and osteoarthritis, normal human tissue arrays, and tissues from other patients with inflammatory diseases displaying neovasculogenesis. In vivo scFv antibody tissue-specific targeting capacity was examined in the human synovial xenograft model using both (125)I-labeled and biotinylated antibody.

RESULTS

We isolated a novel recombinant human antibody, scFv A7, with specificity for the microvasculature of human arthritic synovium. We showed that in vivo, this antibody could efficiently target human synovial microvasculature in SCID mice transplanted with human arthritic synovial xenografts. Our results demonstrated that scFv A7 antibody had no reactivity with the microvasculature or with other cellular components found in a comprehensive range of normal human tissues including normal human synovium. Further, we showed that the reactivity of the scFv A7 antibody was not a common feature of neovasculogenesis associated with chronic inflammatory conditions.

CONCLUSION

Here we report for the first time the identification of an scFv antibody, A7, that specifically recognizes an epitope expressed in the microvasculature of human arthritic synovium and that has the potential to be developed as a joint-specific pharmaceutical.

Soluble fms-like tyrosine kinase-1 antibody for diagnosis purposes (WO2010075475)

BACKGROUND

The application (WO2010075475) is involved in the diagnosis of angiogenesis-dependent diseases related with the soluble FMS-like tyrosine kinase-1 (sFlt-1) biomarker.

OBJECTIVE

It aims to identify, characterize and produce antibodies raised against sFlt-1 for the diagnosis of preeclampsia as well as other cardiovascular diseases.

METHODS

The diagnostic kit is based on a double mAb sandwich assay, comprising of a capture anti-sFlt-1 mAb, grafted onto paramagnetic particles that are able to bind sFlt-1 both in bound and free forms. An acridinium conjugated anti-sFlt-1 antibody, which binds to s-Flt1 on another epitope, serves as a chemioluminescent label.

RESULTS

Using this assay, the total amount of sFlt-1 could be estimated in various biological samples.

CONCLUSION

Antibodies against the free and bound forms of sFlt-1 offer new opportunities in the diagnostics of preeclampsia and other angiogenesis-dependent disorders. Furthermore, as demonstrated in this patent, the immunoassay could be automated and is fast and reliable.

Angiopoietin-2 is highly correlated with inflammation and disease activity in recent-onset rheumatoid arthritis and could be predictive for cardiovascular disease

OBJECTIVE

To investigate whether serum levels of endothelial cell activation markers in early RA patients can serve as biomarkers for inflammation and disease activity, and are associated with radiological progression and development of cardiovascular disease (CVD).

METHODS

Serum levels of VEGF, soluble vascular cell adhesion molecule (sVCAM)-1 and angiopoietin-2 (Angpt-2) were measured by ELISA in 176 patients with recent-onset RA, at the time of diagnosis and after 2 years. Markers of inflammation and disease activity were assessed, as well as radiological damage of hands and feet, at diagnosis and after 2 years. Prevalence of CVD of all patients after 12.5 years disease duration was retrieved from medical records.

RESULTS

Patients with RA had higher levels of VEGF and Angpt-2 at disease onset compared with healthy controls, which correlated with markers of inflammation, but were not predictive of radiological progression after 2 years. Angpt-2 levels, moreover, significantly correlated with measures of disease activity. Nearly 18% of RA patients developed CVD after an average of 12.5 years of disease, and these patients had a significantly higher level of Angpt-2 at the onset of RA compared with patients who did not develop CVD.

CONCLUSIONS

In early RA, markers of endothelial activation are highly correlated with inflammation and disease activity, but not with radiological progression. Angpt-2 could be predictive for the development of CVD since Angpt-2 levels were significantly higher in CVD patients than in non-CVD patients.

Adrenomedullin increases fibroblast-like synoviocyte adhesion to extracellular matrix proteins by upregulating integrin activation

Introduction

Rheumatoid arthritis (RA) is characterized by bone and cartilage invasion by fibroblast-like synoviocytes (FLSs). Adrenomedullin, a peptide with anabolic and antiapoptotic properties, is secreted by rheumatoid FLSs. Adrenomedullin also increases the expression of adhesion molecules in endothelial cells and keratinocytes. Here, we investigated whether adrenomedullin mediated FLS adhesion to extracellular matrix (ECM) proteins.

Methods

FLSs were isolated from synovial tissues from RA and osteoarthritis (OA) patients. Plates were coated overnight with the ECM proteins vitronectin, fibronectin, and type I collagen (Coll.I). Adrenomedullin was used as a soluble FLS ligand before plating. We tested interactions with the adrenomedullin receptor antagonist (22-52)adrenomedullin and with the protein kinase A (PKA) inhibitor H-89, and inhibition of co-receptor RAMP-2 by siRNA. Cell adhesion was measured by using color densitometry. Activation of α₂ and β₁ integrins was evaluated by fluorescent microscopy; integrin inhibition, by RGD peptides; and the talin-integrin interaction, by immunoprecipitation (IP).

Results

Adrenomedullin specifically increased RA-FLS adhesion to vitronectin, fibronectin, and Coll.I; no such effect was found for OA-FLS adhesion. Basal or adrenomedullin-stimulated RA-FLS adhesion was inhibited by (22-52)adrenomedullin, H-89, and RAMP-2 siRNA. Adrenomedullin-stimulated adhesion was inhibited by RGD peptides, and associated with α₂ and β₁ integrin activation. This activation was shown with IP to be related to an integrin-talin interaction and was significantly decreased by (22-52)adrenomedullin.

Conclusions

Adrenomedullin-stimulated RA-FLS adhesion was specific for ECM proteins and mediated by α₂ and β₁ integrins. This effect of adrenomedullin was dependent on adrenomedullin receptors. These results support a new role for adrenomedullin in rheumatoid synovial fibroblast pathobiology.

Blood-induced joint disease: the pathophysiology of hemophilic arthropathy

Arthropathy is a frequent and serious complication of repeated joint bleeding in patients with hemophilia, resulting in pain, deformity, and disability. Although the pathogenesis of hemophilic arthropathy has not been fully elucidated, it appears to have similarities with the degenerative joint damage that occurs in osteoarthritis and the inflammatory processes associated with rheumatoid arthritis. This article reviews the potential actions of various blood constituents on joint components that culminate in the development of hemophilic arthropathy.

Oral administration of high molecular weight hyaluronan (900 kDa) controls immune system via Toll-like receptor 4 in the intestinal epithelium

Low molecular weight hyaluronan enhances or induces inflammation through toll-like receptor 4 (TLR-4). However, the effects of high molecular weight hyaluronan (HA900) on TLR-4 are unknown. In this study, HA900 (900 kDa) was administered orally to MRL-lpr/lpr mice, a Th-1-type autoimmune disease model. Lymphoaccumulation of double-negative T cells, which is enhanced by proinflammatory cytokines, was suppressed by HA900 treatment. Cytokine array analysis showed that HA900 treatment enhanced production of interleukin-10, an anti-inflammatory cytokine, and down-regulated chemokine production. HA900 colocalized with TLR-4 on the luminal surface of epithelial cells in the large intestine. These cells are parts of the immune system and express cytokines. DNA array analysis of the tissue from the large intestine showed that HA900 treatment up-regulated suppressor of cytokine signaling 3 (SOCS3) expression and down-regulated pleiotrophin expression. Treatment of cultured double-negative T cells from MRL-lpr/lpr mice with pleiotrophin rescued these cells. SOCS3, which is known to suppress inflammation, was enhanced by HA900 treatment. In TLR-4 knockdown HT29 cells (a cell line derived from large intestinal cells), HA900 did not bind to HT29 cells and did not up-regulate SOCS3 expression. Our results suggest that oral administration of HA900 modulates Th-1-type autoimmune disease and inflammation by up-regulating SOCS3 expression and down-regulating pleiotrophin expression via TLR-4 in intestinal epithelial cells.

Clinical Significance of Serum Levels of Vascular Endothelial Growth Factor, Angiopoietin-1, and Angiopoietin-2 in Patients with Rheumatoid Arthritis

Objective.

To evaluate the clinical significance of serum levels of vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1), and angiopoietin-2 (Ang-2) in patients with rheumatoid arthritis (RA).

Methods.

The subjects were 70 patients with RA. Serum VEGF, Ang-1, and Ang-2 levels were determined by ELISA. As indices of disease activity, serum levels of C-reactive protein (CRP) and matrix metalloprotease (MMP)-3 were examined, and the 28-joint count Disease Activity Score (DAS28)-CRP was calculated. Power Doppler ultrasonography was performed in the bilateral wrists, elbows, shoulders, knees and ankles. The synovial blood flow signals were scored using a 3-grade scale (0–2), and the total of the scores in the 10 joints was regarded as the total signal score (TSS).

Results.

Serum VEGF level showed significant correlations with serum CRP and MMP-3 levels, DAS28-CRP, and TSS. Serum Ang-1 level showed significant correlations with serum MMP-3 level and DAS28-CRP. Serum Ang-2 level showed significant correlations with serum CRP level and TSS.

Conclusion.

The serum VEGF level is important as an index of the activity of RA based on angiogenesis and a prognostic factor regarding joint destruction. Serum Ang-1 level may be useful as an index of sustained arthritis based on the maintenance of newly formed vessels. Serum Ang-2 level may reflect a state of marked angiogenesis.