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

Unveiling the Anti-Angiogenic Potential of Small-Molecule (Kinase) Inhibitors for Application in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by inflammation leading to joint damage and systemic complications. Angiogenesis promotes inflammation and contributes to RA progression. This study evaluated potential anti-angiogenic effects of several compounds including small-molecule kinase inhibitors, such as sunitinib (pan-kinase inhibitor), tofacitinib (JAK-inhibitor), NIKi (NF-κB-inducing kinase inhibitor), and the integrin-targeting peptide fluciclatide, using a scratch assay and 3D spheroid-based models of angiogenesis. For all drugs tested in the low micromolar range (1-25 μM), sunitinib (as positive anti-angiogenetic control) showed marked inhibition of endothelial cell (EC) migration and sprouting, effectively reducing both scratch closure and sprout formation. Tofacitinib exhibited marginal effectiveness in the scratch assay, but performed better in the 3D models (55% inhibition), whereas NIKi showed around 50% anti-angiogenic effects in both models. Fluciclatide changed EC morphology rather than migration, and only when stimulated with synovial fluid in spheroid model did it show inhibitory effects (at ≥2.5 µM), with none below this dosage. These results highlight the potential of NIKi and tofacitinib for angiogenesis inhibition and of fluciclatide for safe diagnostic targeting of microdose in RA, as well as the need for advanced screening models that mimic RA's complex inflammatory pro-angiogenic environment.

The new anti-angiogenesis perspective of rheumatoid arthritis with geniposide: Reducing the extracellular release of HSP70 in HUVECs

BACKGROUND

Angiogenesis is essential for pannus formation and maintenance in rheumatoid arthritis (RA). Heat shock protein 70 kDa (HSP70) can induce angiogenesis by being released extracellularly through exosomes. Geniposide (GE) is the primary pharmacological component of the fruit of Gardenia jasminoides Ellis (GJ). In vivo, we have found that GE is able to reduce HSP70 levels in the synovium and serum of CIA-S and has anti-angiogenic effects. However, the mechanism by which GE inhibits HSP70 to improve angiogenesis is still unclear. This study aims to explore how GE inhibits the extracellular release of HSP70 and its impact on angiogenesis in human umbilical vein endothelial cells (HUVECs).

METHODS

HUVECs' exosomes were extracted using ultracentrifugation and characterized through transmission electron microscope, nanoparticle tracer technology, nano-flow cytometry and Western blotting. The proliferative ability of HUVECs was assessed by EdU and CCK8 assay. Transwell and wound healing assays were used to measure the migration ability of HUVECs, while tube formation assay was employed to evaluate their tube-forming ability. The TNF-α-induced HSP70 release model in HUVECs was established, with extracellular HSP70 levels serving as an evaluation index. Immunofluorescence and co-immunoprecipitation assay were used to analyze the interaction between HSP70 and the lipid raft marker Caveolin-1 (Cav-1). Western blotting was employed to investigate the expression of SphK1/S1P/S1PRs/Gαi pathway-related proteins, and ELISA was utilized to detect extracellular S1P and HSP70 levels.

RESULTS

The exosomes of HUVECs contained HSP70. HUVECs were stimulated by extracellular HSP70, which enhanced their proliferation, migration, and tube-forming abilities. TNF-α (10 ng/mL) significantly increased the release of HSP70, which was inhibited by GE (25 µM-100 µM) in a concentration-dependent manner. GE reduced HSP70 in lipid rafts without affecting Cav-1. GE (100 µM) inhibited proteins in the SphK1/S1P/S1PRs/Gαi pathway, preventing HSP70 release and improving HUVECs' functions compared to the K6PC-5 (SphK1-specific agonist) and TNF-α groups.

CONCLUSION

This study found that GE inhibited the extracellular release of HSP70 by suppressing the SphK1/S1P/S1PRs/Gαi pathway, thereby producing anti-angiogenic effects in vitro. This provides a novel direction and strategy for anti-angiogenesis therapy for RA.

Bibliometric analysis of research hotspots and trends of lncRNA in angiogenesis-related diseases

OBJECTIVES

Long noncoding RNAs (lncRNA) play important roles in the pathological processes of angiogenesis-related diseases such as cancer and diabetic retinopathy. This study aims to identify global research trends and hotspots in the field of lncRNAs in angiogenesis-related diseases and to explore future research directions.

METHODS

Relevant literature published between 2012 and 2022 was retrieved from the Web of Science Core Collection (WoSCC). A total of 1 516 articles on lncRNAs and angiogenesis-related diseases were included for bibliometric analysis. CiteSpace and VOSviewer were used to analyze publication countries, institutions, journals, authors, co-cited references, and key words.

RESULTS

The number of publications in this field has shown a steadily increasing trend from 2012 to 2022, peaking in 2021. China has the highest number of publications, while the United States ranked highest in centrality. Nanjing Medical University was the most prolific institution. Liu Y was the most productive author, while Wang Y ranked first in co-citation frequency. Cell was the most frequently cited journal. The latest terms of burst key words were vascular remodeling, dysfunction, heart, target, suppress, and pulmonary arterial hypertension.

CONCLUSIONS

From 2012 to 2022, research on lncRNAs in angiogenesis-related diseases has grown significantly. China leads in publication volume, while the United States holds the most academic influence. Emerging research hotspots such as vascular remodeling and dysfunction point to key directions for future research.

Application of superb microvascular imaging technology in clinical disease activity of rheumatoid arthritis

OBJECTIVES

Detection of synovitis is essential for assessing the activity and predicting the prognosis of rheumatoid arthritis (RA). The aim of this study was to investigate the diagnostic performance of superb microvascular imaging (SMI) in RA patients with high, moderate, and low activity.

METHODS

One hundred four patients with active RA were selected from the hospital between May 2022 and August 2023. The study observed the correlation between bone erosion of the carpal joint, joint cavity effusion, thickness of synovial hyperplasia of the carpal joint, positivity rate of synovial blood vessels, and their semiquantitative scores with the clinical disease activity of RA using SMI examination.

RESULTS

The detection of synovial hyperplasia thickness and joint effusion in the high-activity group was higher than that in the low-activity group, and the difference was statistically significant (P < 0.05). The quantitative SMI test demonstrated that the synovial blood flow grading and semiquantitative grade increased gradually with activity level (P<0.05). During the high, moderate, and low-activity groups, the vascular index (VI) value of the hyperplastic synovial membrane decreased gradually, showing statistical significance both between and within the groups (P<0.05).

CONCLUSION

SMI technology exhibited high sensitivity and accuracy in assessing disease activity in RA. It holds significant clinical application value as a reliable auxiliary tool for assessing disease activity in RA and treatment. Key Points • Super micro-vascular imaging (SMI) demonstrated higher detection rates of microvessels in RA patients with high disease activity compared to those with low activity, showing statistical significance. • The quantitative SMI test revealed a clear correlation between synovial blood flow grading and disease activity levels in RA patients, highlighting the potential of SMI as a valuable tool for disease activity and treatment of rheumatoid arthritis.

Dual targeting heterodimer PET tracer [18F]AlF‑FAPI‑RGD in patients with rheumatoid arthritis: a pilot exploratory study

Purpose: Fibroblast-like synoviocytes and angiogenesis play crucial roles in the advancement of rheumatoid arthritis (RA). This prospective study aimed to assess the efficacy of [18F]AlF-FAPI-RGD, a dual-targeting heterodimer tracer that focuses on fibroblast activation protein (FAP) and integrin αvβ3, through PET/CT imaging for evaluating disease activity and response to treatment in RA. Methods: Twenty-eight participants with active RA (12 males and 16 females; mean age, 55 ± 9 years) underwent clinical evaluation of disease activity and [18F]AlF-FAPI-RGD PET/CT imaging at enrollment. Subsequently, after a 3-month period, a follow-up scan and clinical assessments were conducted on these participants. Imaging parameters such as PET-positive joint count (PJC), PET-positive articular index (PAI), average SUVmax (aSUVmax), and highest SUVmax (hSUVmax) in affected joints were compared with clinical and laboratory findings, as well as traditional imaging modalities. Results: [18F]AlF-FAPI-RGD PET/CT imaging produced high-quality images, revealing notable tracer uptake in the synovium of affected joints. [18F]AlF-FAPI-RGD demonstrated a higher positivity rate in detecting affected joints compared to the tender or swollen joint counts during clinical assessment (82.4% [342 of 415] vs 68.4% [284 of 415], respectively). Additionally, this imaging method successfully identified lung lesions with atypical respiratory symptoms in participants with RA. Following treatment, PJC, PAI, aSUVmax, and hSUVmax values significantly decreased in responders (P < 0.001), while no significant changes were observed in non-responders (P > 0.05). Furthermore, a notable association was found between the percentage change in certain PET parameters and modifications in specific clinical parameters. Conclusion: [18F]AlF-FAPI-RGD PET/CT represents a promising tool for the objective assessment of disease activity and treatment response in patients with RA. Furthermore, it may offer a novel imaging method for the early detection of subclinical RA and interstitial lung disease present with atypical respiratory symptoms.

Delivery technologies for therapeutic targeting of fibronectin in autoimmunity and fibrosis applications

Fibronectin (FN) is a critical component of the extracellular matrix (ECM) contributing to various physiological processes, including tissue repair and immune response regulation. FN regulates various cellular functions such as adhesion, proliferation, migration, differentiation, and cytokine release. Alterations in FN expression, deposition, and molecular structure can profoundly impact its interaction with other ECM proteins, growth factors, cells, and associated signaling pathways, thus influencing the progress of diseases such as fibrosis and autoimmune disorders. Therefore, developing therapeutics that directly target FN or its interaction with cells and other ECM components can be an intriguing approach to address autoimmune and fibrosis pathogenesis.

CPD-002, a novel VEGFR2 inhibitor, relieves rheumatoid arthritis by reducing angiogenesis through the suppression of the VEGFR2/PI3K/AKT signaling pathway

Synovial angiogenesis is a key player in the development of rheumatoid arthritis (RA), and anti-angiogenic therapy is considered a promising approach for treating RA. CPD-002 has demonstrated efficacy in suppressing tumor angiogenesis as a VEGFR2 inhibitor, but its specific impacts on RA synovial angiogenesis and possible anti-RA effects need further study. We examined the influences of CPD-002 on the migration and invasion of human umbilical vein endothelial cells (HUVECs) and its impacts on HUVECs' tube formation and vessel sprouting ex vivo. The therapeutic potential of CPD-002 in adjuvant-induced arthritis (AIA) rats and its suppression of synovial angiogenesis were examined. The involvement of the VEGFR2/PI3K/AKT pathway was assessed both in HUVECs and AIA rat synovium. Here, CPD-002 inhibited the migration and invasion of VEGF-stimulated HUVECs, decreased their chemotactic response to RA fibroblast-like synoviocyte-released chemoattractants, and exhibited anti-angiogenic effects in vitro and ex vivo. CPD-002's targeting of VEGFR2 was confirmed with molecular docking and cellular thermal shift assays, supported by the abolishment of CPD-002's effects upon using VEGFR2 siRNA. CPD-002 relieved paw swelling, arthritis index, joint damage, and synovial angiogenesis, indicating its anti-arthritic and anti-angiogenic effects in AIA rats. Moreover, the anti-inflammatory effects in vivo and in vitro of CPD-002 contributed to its anti-angiogenic effects. Mechanistically, CPD-002 hindered the activation of VEGFR2/PI3K/AKT pathway in VEGF-induced HUVECs and AIA rat synovium, as evidenced by reduced p-VEGFR2, p-PI3K, and p-AKT protein levels alongside elevated PTEN protein levels. Totally, CPD-002 showed anti-rheumatoid effects via attenuating angiogenesis through the inhibition of the VEGFR2/PI3K/AKT pathway.

Role of PET/CT in diagnosing and monitoring disease activity in rheumatoid arthritis: a review

Rheumatoid Arthritis (RA) is a systemic inflammatory disorder that commonly presents with polyarthritis but can have multisystemic involvement and complications, leading to increased morbidity and mortality. The diagnosis of RA continues to be challenging due to its varied clinical presentations. In this review article, we aim to determine the potential of PET/CT to assist in the diagnosis of RA and its complications, evaluate the therapeutic response to treatment, and predict RA remission. PET/CT has increasingly been used in the last decade to diagnose, monitor treatment response, predict remissions, and diagnose subclinical complications in RA. PET imaging with [18F]-fluorodeoxyglucose ([18F]-FDG) is the most commonly applied radiotracer in RA, but other tracers are also being studied. PET/CT with [18F]-FDG, [18F]-NaF, and other tracers might lead to early identification of RA and timely evidence-based clinical management, decreasing morbidity and mortality. Although PET/CT has been evolving as a promising tool for evaluating and managing RA, more evidence is required before incorporating PET/CT in the standard clinical management of RA.

Naru-3 inhibits inflammation, synovial hyperplasia, and neovascularization in collagen-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Naru-3 is a prescribed formulation based on the theory of Mongolian medicine for the treatment of rheumatoid arthritis (RA). Naru-3 consists of three medicinal agents: Aconitum kusnezoffii Reichb (caowu), Terminalia chebula Retz (hezi), and Piper longum L (biba). These medicinal agents are widely distributed in the Mongolian area of China and have been used to treat rheumatism for centuries.

BACKGROUND

Mongolian medicine Naru-3 is commonly prescribed to treat RA, but its mechanism of action is unknown.

METHODS

A rat collagen-induced arthritis (CIA) model was established to investigate the mechanism of Naru-3. Rats were treated with Naru-3, Etanercept (ETN), and sodium carboxymethylcellulose (CMC) for four weeks. After treatment was terminated, paw thickness, ankle diameter, and arthritis index (AI) were scored. Synovial hyperplasia was evaluated using hematoxylin and eosin (H&E) staining and two-dimensional ultrasonography. Synovitis and neovascularization were assayed using power Doppler imaging (PDI) and contrast-enhanced ultrasonography (CEUS). Levels of vascular endothelial growth factor (VEGF), interleukin (IL)-1, and CD31 in the serum or synovium were detected using ELISA and immunohistochemistry analyses.

RESULTS

Naru-3 and ETN alleviated the symptoms of CIA as evidenced by diminished paw thickness, ankle diameter, and AI scores. Mechanistically, Naru-3 inhibited synovial hyperplasia, synovitis, and neovascularization by diminishing systemic and local inflammation, as indicated by the relative expression of CD31, VEGF and IL-1 in the serumor synovium. After four weeks of treatment, no significant neovascularization was observed in the Naru-3 group, but neovascularization and synovitis occurred in the ETN group, as demonstrated by H&E staining, PDI, and CEUS examination.

CONCLUSION

Naru-3 inhibited inflammation, synovial hyperplasia, and neovascularization and alleviates RA in our CIA rat model. No symptom recurrence was observed four weeks after drug treatment.

Computational Fluid Dynamics (CFD) Model for Analysing the Role of Shear Stress in Angiogenesis in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterised by an attack on healthy cells in the joints. Blood flow and wall shear stress are crucial in angiogenesis, contributing to RA's pathogenesis. Vascular endothelial growth factor (VEGF) regulates angiogenesis, and shear stress is a surrogate for VEGF in this study. Our objective was to determine how shear stress correlates with the location of new blood vessels and RA progression. To this end, two models were developed using computational fluid dynamics (CFD). The first model added new blood vessels based on shear stress thresholds, while the second model examined the entire blood vessel network. All the geometries were based on a micrograph of RA blood vessels. New blood vessel branches formed in low shear regions (0.840-1.260 Pa). This wall-shear-stress overlap region at the junctions was evident in all the models. The results were verified quantitatively and qualitatively. Our findings point to a relationship between the development of new blood vessels in RA, the magnitude of wall shear stress and the expression of VEGF.

Update on Imaging of Inflammatory Arthritis and Related Disorders

Arthritis and other rheumatic disorders are very frequent in the general population and responsible for a huge physical and disability burden to affected patients as well as a major cost to the society. Precise evaluation often relies on clinical data only but additional imaging may be required i) for a more objective assessment of the disease status, such as in rheumatoid arthritis (RA) or ankylosing spondyloarthritis (AS), ii) for providing prognostic information and evaluating response to treatment or iii) for establishing diagnosis, in patients with unclear clinical picture, such as polymyalgia rheumatica (PMR) and large-vessel vasculitis (LVV). Besides radiological techniques (x-rays, ultrasound, and MRI), functional and molecular imaging has emerged as a valid tool for this purpose in several disorders. Bone scanning has long been a method of choice but is now more used as a triage tool in patients with unclear complaints, including degenerative disorders (eg osteoarthritis). ¹⁸F-FDG-PET/CT (FDG) proved efficient in assessing the extent of the disease and response to treatment in RA and related disorders, and to provide accurate diagnosis in some systemic disorders, including PMR and LVV. Based on glucose metabolism, FDG-PET/CT is able to show increased metabolism in peripheral cells involved in inflammation (eg neutrophils, lymphocytes or monocytes/macrophages) but also in fibroblasts that proliferate in the pannus. The lack of specificity of FDG is a limitation and many alternative tracers were developed at the preclinical stage or applied in the clinics, especially within clinical trials. They include imaging of macrophages using translocator protein (TSPO), folate-receptors or other targets on activated cells. These new tools will undoubtedly become more and more available in the everyday clinical workup of patients with rheumatisms. Finally, it should be kept in mind that a very simple tracer, ¹⁸F-fluoride is widely more performant in AS than FDG.

Assessment of Angiopoietin-2 Single Nucleotide Polymorphism in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease that destroys joint cartilage and causes disability. Synovial inflammation, with angiogenesis, is an early event in the progression of the disease. Angiopoietin 2 (ANGPT2) is a cytokine with both inflammatory and angiogenic effects. Many genes can influence RA susceptibility and disease activity. The aim is to assess the relationship between ANGPT2 gene polymorphism (rs3020221) and RA. The study was a case-control study that included 212 RA patients and 238 age-and gender-matched healthy volunteers. RA disease activity was assessed using the Disease Activity Score 28 index. Erythrocyte sedimentation rate, C-reactive protein, rheumatoid factor, and antibody to cyclic citrullinated peptide were measured. ANGPT2 rs3020221 C > T SNP genotyping was done using real-time polymerase chain reaction (PCR). The TT genotype was more frequently represented in RA patients than in healthy controls (18.9% and 7.1%, respectively, p < 0.001) and increased the chance of developing RA four-fold, as compared to other genotypes (OR = 4.00, 95% CI = 2.09-7.63) (p < 0.001). The CT genotype was associated with elevated levels of the inflammatory markers ESR and CRP in RA patients (p = 0.012 and 0.037, respectively) as well as the DAS28 ESR Score (p < 0.001). The presence of the T allele either under the dominant model (for genotypes CT and TT) or the recessive model (for the genotype TT) predicts RA disease. Assessment of ANGPT2 gene polymorphism is useful to predict the patients with susceptibility to RA. The presence of T allele increased the risk of developing RA disease by two folds.

Emerging insights of peptide-based nanotherapeutics for effective management of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, prevalent, immune-mediated, inflammatory, joint disorder affecting millions of people worldwide. Despite current treatment options, many patients remain unable to achieve remission and suffer from comorbidities. Because of several comorbidities as well as its chronic nature, it diminishes the quality of patients' life and intensifies socioeconomic cargo. Consolidating peptides with immensely effective drug delivery systems has the ability to alleviate adverse effects associated with conventional treatments. Peptides are widely used as targeting moieties for the delivery of nanotherapeutics. The use of novel peptide-based nanotherapeutics may open up new avenues for improving efficacy by promoting drug accumulation in inflamed joints and reducing off-target cytotoxicity. Peptide therapeutics have grabbed significant attention due to their advantages over small drug molecules as well as complex targeting moieties. In light of this, the market for peptide-based medications is growing exponentially. Peptides can provide the versatility required for the successful delivery of drugs due to their structural diversity and their capability to lead drugs at the site of inflammation while maintaining optimum therapeutic efficacy. This comprehensive review aims to provide an enhanced understanding of recent advancements in the arena of peptide-based nanotherapeutics to strengthen targeted delivery for the effective management of rheumatoid arthritis. Additionally, various peptides having therapeutic roles in rheumatoid arthritis are summarized along with regulatory considerations for peptides.