Chin Teck Ng

Bio: Chin Teck Ng is an academic researcher from Singapore General Hospital. The author has contributed to research in topics: Inflammatory arthritis & Arthritis. The author has an hindex of 22, co-authored 41 publications receiving 1535 citations. Previous affiliations of Chin Teck Ng include National University of Singapore & University College Dublin.

Synovial tissue hypoxia and inflammation in vivo

Abstract: Introduction Hypoxia is a microenvironmental feature in the inflamed joint, which promotes survival advantage for cells. The aim of this study was to examine the relationship of partial oxygen pressure in the synovial tissue (tPO 2 ) in patients with inflammatory arthritis with macroscopic/microscopic inflammation and local levels of proinflammatory mediators. Methods Patients with inflammatory arthritis underwent full clinical assessment and video arthroscopy to quantify macroscopic synovitis and measure synovial tPO 2 under direct visualisation. Cell specific markers (CD3 (T cells), CD68 (macrophages), Ki67 (cell proliferation) and terminal deoxynucleotidyl transferase dUTP nick end labelling (cell apoptosis)) were quantified by immunohistology. In vitro migration was assessed in primary and normal synoviocytes (synovial fibroblast cells (SFCs)) using a wound repair scratch assay. Levels of tumour necrosis factor α (TNFα), interleukin 1β (IL1β), interferon γ (IFNγ), IL6, macrophage inflammatory protein 3α (MIP3α) and IL8 were quantified, in matched serum and synovial fluid, by multiplex cytokine assay and ELISA. Results The tPO 2 was 22.5 (range 3.2–54.1) mm Hg and correlated inversely with macroscopic synovitis (r=−0.421, p=0.02), sublining CD3 cells (−0.611, p 2 in vivo) induced cell migration. This was coupled with significantly higher levels of synovial fluid tumour necrosis factor α (TNFα), IL1β, IFNγ and MIP3α in patients with tPO 2 Conclusions This is the first study to show a direct in vivo correlation between synovial tPO 2 , inflammation and cell migration, thus it is proposed that hypoxia is a possible primary driver of inflammatory processes in the arthritic joint.

Dysregulated bioenergetics: a key regulator of joint inflammation

Abstract: Objectives This study examines the relationship between synovial hypoxia and cellular bioenergetics with synovial inflammation. Methods Primary rheumatoid arthritis synovial fibroblasts (RASF) were cultured with hypoxia, dimethyloxalylglycine (DMOG) or metabolic intermediates. Mitochondrial respiration, mitochondrial DNA mutations, cell invasion, cytokines, glucose and lactate were quantified using specific functional assays. RASF metabolism was assessed by the XF24-Flux Analyzer. Mitochondrial structural morphology was assessed by transmission electron microscopy (TEM). In vivo synovial tissue oxygen (tpO 2 mmHg) was measured in patients with inflammatory arthritis (n=42) at arthroscopy, and markers of glycolysis/oxidative phosphorylation (glyceraldehyde 3-phosphate dehydrogenase (GAPDH), PKM2, GLUT1, ATP) were quantified by immunohistology. A subgroup of patients underwent contiguous MRI and positron emission tomography (PET)/CT imaging. RASF and human dermal microvascular endothelial cells (HMVEC) migration/angiogenesis, transcriptional activation (HIF1α, pSTAT3, Notch1-IC) and cytokines were examined in the presence of glycolytic inhibitor 3-(3-Pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO). Results DMOG significantly increased mtDNA mutations, mitochondrial membrane potential, mitochondrial mass, reactive oxygen species and glycolytic RASF activity with concomitant attenuation of mitochondrial respiration and ATP activity (all p 2 levels 2 in tumour necrosis factor alpha inhibitor (TNFi) responders. Novel PET/MRI hybrid imaging demonstrated close association between metabolic activity and inflammation. 3PO significantly inhibited RASF invasion/migration, angiogenic tube formation, secretion of proinflammatory mediators (all p Conclusions Hypoxia alters cellular bioenergetics by inducing mitochondrial dysfunction and promoting a switch to glycolysis, supporting abnormal angiogenesis, cellular invasion and pannus formation.

Angiogenesis and blood vessel stability in inflammatory arthritis.

Abstract: Objective To assess blood vessel stability in inflammatory synovial tissue (ST) and to examine neural cell adhesion molecule (NCAM), oxidative DNA damage, and hypoxia in vivo. Methods Macroscopic vascularity and ST oxygen levels were determined in vivo in patients with inflammatory arthritis who were undergoing arthroscopy. Vessel maturity/stability was quantified in matched ST samples by dual immunofluorescence staining for factor VIII (FVIII)/α-smooth muscle actin (α-SMA). NCAM and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) were examined by immunohistochemistry. Angiogenesis was assessed in vitro, using human dermal endothelial cells (HDECs) in a Matrigel tube formation assay. Results A significant number of immature vessels (showing no pericyte recruitment) was observed in tissue from patients with inflammatory arthritis (P < 0.001), in contrast to osteoarthritic and normal tissue, which showed complete recruitment of pericytes. Low in vivo PO2 levels in the inflamed joint (median [range] 22.8 [3.2–54.1] mm Hg) were inversely related to increased macroscopic vascularity (P < 0.04) and increased microscopic expression of FVIII and α-SMA (P < 0.04 and P < 0.03, respectively). A significant proportion of vessels showed focal expression of NCAM and strong nuclear 8-oxodG expression, implicating a loss of EC–pericyte contact and increased DNA damage, levels of which were inversely associated with low in vivo PO2 (P = 0.04 for each comparison). Circulating cells were completely negative for 8-oxodG. Exposure of HDEC to 3% O2 (reflecting mean ST in vivo measurements) significantly increased EC tube formation (P < 0.05). Conclusion Our findings indicate the presence of unstable vessels in inflamed joints associated with hypoxia, incomplete EC–pericyte interactions, and increased DNA damage. These changes may further contribute to persistent hypoxia in the inflamed joint to further drive this unstable microenvironment.

2018 update of the APLAR recommendations for treatment of rheumatoid arthritis

Abstract: Aim: To update recommendations based on current best evidence concerning the treatment of rheumatoid arthritis (RA), focusing particularly on the role of targeted therapies, to inform clinicians on new developments that will impact their current practice. Materials and methods: A search of relevant literature from 2014 to 2016 concerning targeted therapies in RA was conducted. The RA Update Working Group evaluated the evidence and proposed updated recommendations using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach, to describe the quality of evidence and strength of recommendations. Recommendations were finalized through consensus using the Delphi technique. Results: This update provides 16 RA treatment recommendations based on current best evidence and expert clinical opinion. Recommendations 1-3 deal with the use of conventional synthetic disease-modifying antirheumatic drugs. The next three recommendations (4-6) cover the need for screening and management of infections and comorbid conditions prior to starting targeted therapy, while the following seven recommendations focus on use of these agents. We address choice of targeted therapy, switch, tapering and discontinuation. The last three recommendations elaborate on targeted therapy for RA in special situations such as pregnancy, cancer, and major surgery. Conclusion: Rheumatoid arthritis remains a significant health problem in the Asia-Pacific region. Patients with RA can benefit from the availability of effective targeted therapies, and these updated recommendations provide clinicians with guidance on their use.

APLAR rheumatoid arthritis treatment recommendations

Abstract: Aims: Rheumatoid arthritis is a chronic inflammatory condition that affects approximately 1% of the world's population. There are a wide number of guidelines and recommendations available to support the treatment of rheumatoid arthritis; however, the evidence used for these guidelines is predominantly based on studies in Caucasian subjects and may not be relevant for rheumatoid arthritis patients in the Asia-Pacific region. Therefore, the Asia Pacific League of Associations for Rheumatology established a Steering Committee in 2013 to address this issue. Materials and methods: The AGREE II instrument and the ADAPTE Collaboration framework were applied to systematically identify, appraise, synthesize, and adapt international rheumatoid arthritis guidelines for use in the Asia-Pacific region. Results: Forty rheumatoid arthritis treatment recommendations, based on evidence and expert opinion, were drafted and are presented in this report. Conclusion: The Asia Pacific of Associations for Rheumatology rheumatoid arthritis treatment recommendations are intended to serve as a reference for best practice management of rheumatoid arthritis in Asia-Pacific, focusing on local issues to ensure the delivery of basic care for these patients, and to improve their outcomes. In addition, the document will serve as a reference for national rheumatology associations in Asia-Pacific for developing guidelines in their respective countries. International Journal of Rheumatic Diseases

EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2016 update

Abstract: In this article, the 2010 European League against Rheumatism (EULAR) recommendations for the management of rheumatoid arthritis (RA) with synthetic and biological disease-modifying antirheumatic drugs (sDMARDs and bDMARDs, respectively) have been updated. The 2013 update has been developed by an international task force, which based its decisions mostly on evidence from three systematic literature reviews (one each on sDMARDs, including glucocorticoids, bDMARDs and safety aspects of DMARD therapy); treatment strategies were also covered by the searches. The evidence presented was discussed and summarised by the experts in the course of a consensus finding and voting process. Levels of evidence and grades of recommendations were derived and levels of agreement (strengths of recommendations) were determined. Fourteen recommendations were developed (instead of 15 in 2010). Some of the 2010 recommendations were deleted, and others were amended or split. The recommendations cover general aspects, such as attainment of remission or low disease activity using a treat-to-target approach, and the need for shared decision-making between rheumatologists and patients. The more specific items relate to starting DMARD therapy using a conventional sDMARD (csDMARD) strategy in combination with glucocorticoids, followed by the addition of a bDMARD or another csDMARD strategy (after stratification by presence or absence of adverse risk factors) if the treatment target is not reached within 6 months (or improvement not seen at

Targeting IL-17 and TH17 cells in chronic inflammation.

Abstract: The key role of interleukin-17 (IL-17) and T helper 17 (T(H)17) cells in tissue inflammation, autoimmunity and host defence led to the experimental targeting of these molecules in mouse models of diseases as well as in clinical settings. Moreover, the demonstration that IL-17 and T(H)17 cells contribute to local and systemic aspects of disease pathogenesis, as well as the finding that the IL-17-T(H)17 cell pathway is regulated by IL-23, prompted the identification of inhibitors. These inhibitors include biotechnology products that target IL-23 as well as the leading member of the IL-17 family, IL-17A, and one of its receptors, IL-17 receptor A. Several clinical trials of these inhibitors are underway, and positive results have been obtained in psoriasis, rheumatoid arthritis and ankylosing spondylitis. This Review focuses on the current knowledge of the IL-17-T(H)17 cell pathway to better understand the positive as well as potential negative consequences of targeting them.

Metabolic regulation of T lymphocytes.

Abstract: T cell activation leads to dramatic shifts in cell metabolism to protect against pathogens and to orchestrate the action of other immune cells. Quiescent T cells require predominantly ATP-generating processes, whereas proliferating effector T cells require high metabolic flux through growth-promoting pathways. Further, functionally distinct T cell subsets require distinct energetic and biosynthetic pathways to support their specific functional needs. Pathways that control immune cell function and metabolism are intimately linked, and changes in cell metabolism at both the cell and system levels have been shown to enhance or suppress specific T cell functions. As a result of these findings, cell metabolism is now appreciated as a key regulator of T cell function specification and fate. This review discusses the role of cellular metabolism in T cell development, activation, differentiation, and function to highlight the clinical relevance and opportunities for therapeutic interventions that may be used to disrupt immune pathogenesis.

Hypoxia-inducible factor-1 alpha–dependent induction of FoxP3 drives regulatory T-cell abundance and function during inflammatory hypoxia of the mucosa

Abstract: Recent studies have demonstrated dramatic shifts in metabolic supply-and-demand ratios during inflammation, a process resulting in localized tissue hypoxia within inflammatory lesions (“inflammatory hypoxia”). As part of the adaptive immune response, T cells are recruited to sites of inflammatory hypoxia. Given the profound effects of hypoxia on gene regulation, we hypothesized that T-cell differentiation is controlled by hypoxia. To pursue this hypothesis, we analyzed the transcriptional consequences of ambient hypoxia (1% oxygen) on a broad panel of T-cell differentiation factors. Surprisingly, these studies revealed selective, robust induction of FoxP3, a key transcriptional regulator for regulatory T cells (Tregs). Studies of promoter binding or loss- and gain-of-function implicated hypoxia-inducible factor (HIF)-1α in inducing FoxP3. Similarly, hypoxia enhanced Treg abundance in vitro and in vivo. Finally, Treg-intrinsic HIF-1α was required for optimal Treg function and Hif1a–deficient Tregs failed to control T-cell–mediated colitis. These studies demonstrate that hypoxia is an intrinsic molecular cue that promotes FoxP3 expression, in turn eliciting potent anti-inflammatory mechanisms to limit tissue damage in conditions of reduced oxygen availability.