Serum adenosine deaminase in patients with rheumatoid arthritis treated with methotrexate

Comparison of Adenosine Deaminase, C-reactive Protein, Uric Acid, and Rheumatoid Arthritis Levels in Patients With Rheumatoid Arthritis and Those Without Arthritis: A Review

One of the hallmarks of rheumatoid arthritis (RA) is inflammation of the synovial membrane, and oxidative stress is a mediator of tissue damage. RA is characterized by persistent joint inflammation, which leads to pain, edema, and finally joint destruction. Numerous biochemical markers can cause RA because of their impact on systemic and local inflammation. Numerous biomarkers have been investigated for their potential application in the diagnosis and prognosis of RA. In this review article, we evaluate the role of RA factor or rheumatoid factor (RF), uric acid, C-reactive protein (CRP), and adenosine deaminases (ADAs) as biomarkers in patients with and without arthritis. Studies that analyze and compare the levels of uric acid, ADAs, CRP, and RF in patients with and without arthritis. Although recent research has shown higher levels of uric acid, ADA, CRP, and RA in patients with RF compared to healthy controls, these findings may indicate a role for these markers in reflecting inflammation and disease activity. In the metabolism of purines, the enzyme ADA is involved. The liver produces CRP, which is then released into the bloodstream. In inflammatory situations, there is a rise in CRP levels. This biomarker is frequently used for systemic inflammatory assessment in RA. The pathophysiology and severity of RA have both been connected to uric acid, which has historically been linked to gout. One particular biomarker for RA is RF. When compared to a healthy control group of individuals with arthritis, this review provides valuable insights into the diagnostic and prognostic use of uric acid, CRP, ADAs, and RF.

Pathogenic Th17 cells in autoimmunity with regard to rheumatoid arthritis

Th17 cells contribute the pathobiology of autoimmune diseases, including rheumatoid arthritis (RA). However, it was shown that differentiated Th17 cells display a high degree of plasticity under the influence of inflammatory conditions. In some autoimmune diseases, the majority of Th17 cells, especially at sites of inflammation, have a phenotype that is intermediate between Th17 and Th1. These cells, which are described as Th17.1 or exTh17 cells, are hypothesized to be more pathogenic than classical Th17 cells. In this review, the involvement of Th17.1 lymphocytes in RA, and potential features that might render these cells to be more pathogenic are discussed.

Adenosine Deaminase Gene Polymorphism and Baseline Serum Level of Adenosine Deaminase as a Biomarker of Response to Methotrexate in Rheumatoid Arthritis

BACKGROUND

Methotrexate (MTX) is the first-line therapy for rheumatoid arthritis (RA), but nearly 30% of RA patients do not respond to it. Methotrexate acts by enhancing the level of adenosine, which gets converted to inosine by the enzyme adenosine deaminase (ADA). We studied whether ADA gene polymorphism and serum levels of total ADA are associated with responsiveness to MTX.

METHODS

Two hundred seven disease-modifying antirheumatic drug-naive active RA patients (DAS28-ESR [Disease Activity Score-28 for rheumatoid arthritis with erythrocyte sedimentation rate] ≥3.2) satisfying the European League Against Rheumatism (EULAR)/American College of Rheumatology 2010 criteria were enrolled. Genotyping was done in all patients, and in a subset (n = 59), blood was collected at baseline and at 2 months of MTX treatment for serum total ADA estimation by ELISA. Response at 4 months was assessed by EULAR criteria, and patients were classified as responders or nonresponders. The correlation of baseline clinical parameters, ADA gene polymorphism, and serum total ADA levels with EULAR response was sought.

RESULTS

After 4 months of MTX monotherapy, 172 patients (83.1%) were classified as responders and 35 (16.9%) as nonresponders. Except DAS28-ESR (6.1 [5.43-6.84] in responders vs 5.6 [4.77-6.21] in nonresponders, p = 0.02), other baseline parameters (age, disease duration, ESR, and C-reactive protein level) were similar between responders and nonresponders. Single nucleotide polymorphisms in ADA gene, baseline serum ADA levels (10.52 ± 5.37 ng/mL in responders vs 12.28 ± 5.14 ng/mL in nonresponders), or change in ADA levels after 2 months of MTX therapy did not show any association with MTX response (p = 0.73, p = 0.34, p = 0.55, respectively). Adenosine deaminase genotype did not affect the blood ADA level.

CONCLUSIONS

No association was seen between ADA single nucleotide polymorphism rs244076 as well as serum ADA level and response to MTX therapy.

Adenosine deaminase modulates metabolic remodeling and orchestrates joint destruction in rheumatoid arthritis

Rheumatoid Arthritis (RA) is a chronic autoimmune disease associated with inflammation and joint remodeling. Adenosine deaminase (ADA), a risk factor in RA, degrades adenosine, an anti-inflammatory molecule, resulting in an inflammatory bias. We present an integrative analysis of clinical data, cytokines, serum metabolomics in RA patients and mechanistic studies on ADA-mediated effects on in vitro cell culture models. ADA activity differentiated patients into low and high ADA sets. The levels of the cytokines TNFα, IFNγ, IL-10, TGFβ and sRANKL were elevated in RA and more pronounced in high ADA sets. Serum metabolomic analysis shows altered metabolic pathways in RA which were distinct between low and high ADA sets. Comparative analysis with previous studies shows similar pathways are modulated by DMARDs and biologics. Random forest analysis distinguished RA from control by methyl-histidine and hydroxyisocaproic acid, while hexose-phosphate and fructose-6-phosphate distinguished high ADA from low ADA. The deregulated metabolic pathways of High ADA datasets significantly overlapped with high ADA expressing PBMCs GEO transcriptomics dataset. ADA induced the death of chondrocytes, synoviocyte proliferation, both inflammation in macrophages and their differentiation into osteoclasts and impaired differentiation of mesenchymal stem cells to osteoblasts and mineralization. PBMCs expressing elevated ADA had increased expression of cytokines and P2 receptors compared to synovial macrophages which has low expression of ADA. Our data demonstrates increased cytokine levels and distinct metabolic signatures of RA based on the ADA activity, suggests an important role for ADA in the pathophysiology of RA joints and as a potential marker and therapeutic target in RA patients.

ATP and adenosine: Role in the immunopathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is a classic inflammatory autoimmune disease. Local joint destruction and extra-articular manifestations of RA deeply compromise the life quality of the affected patients. RA immunopathogenesis depends on continuous immunogenic activation in which the purinergic system participates. The purinergic system comprises the signaling and metabolism of purines such as adenosine triphosphate (ATP) and adenosine. ATP signaling is involved in the activation and maintenance of the inflammatory state of RA through the activation of P2X7 and the production of cytokines, which orchestrate the pathogenesis of RA. The breakdown of ATP through the CD39/CD73 axis produces adenosine, which mostly inhibits the inflammatory process through activation of specific P1 receptors. Adenosine is hydrolyzed by adenosine deaminase (ADA) that interacts with other molecules playing additional roles in this disease. This review explores the release, metabolism, and the effects of binding of ATP and adenosine to their respective receptors in the context of RA, as well as their potential use as biomarkers and therapeutic targets.

Salivary adiponectin, but not adenosine deaminase, correlates with clinical signs in women with Sjögren's syndrome: a pilot study

OBJECTIVES

To evaluate salivary adiponectin and adenosine deaminase (ADA) in women suffering from Sjögren's syndrome (SS).

METHODS

Salivary adiponectin and ADA were measured in patients with SS (n = 17) and compared to their values in healthy controls (n = 13) and patients suffering from drug-induced xerostomia (non-SS sicca group; n = 19). A clinical history was made for each patient, patients were examined clinically, and xerostomia inventory (XI) was performed.

RESULTS

Salivary adiponectin corrected by total protein was higher in patients with SS than in healthy individuals (P < 0.05) or patients with non-SS sicca (P < 0.01) and correlated with XI (r = 0.555; P < 0.05). Salivary ADA was higher in patients with SS and non-SS sicca compared to controls (P < 0.05 in both cases).

CONCLUSION

The results of the present study indicate that adiponectin and ADA are increased in the saliva of patients with SS.

CLINICAL RELEVANCE

Salivary adiponectin corrected by total protein can be a potential biomarker of SS.

TRIAL REGISTRATION

NCT03156569.

Repeated Electroacupuncture Persistently Elevates Adenosine and Ameliorates Collagen-Induced Arthritis in Rats

The aim of this paper was to investigate the effect of repeated electroacupuncture (EA) over 21 days on the adenosine concentration in peripheral blood of rats with collagen-induced arthritis (CIA). Wistar rats were divided into three groups of 6 animals each: sham-control, CIA-control, and CIA-EA. We determined the adenosine concentration in peripheral blood and assessed pathological changes of ankle joints. Quantitative reverse-transcription-polymerase chain reaction was used to determine mRNA levels of ecto-5'-nucleotidase (CD73), adenosine deaminase (ADA), and tumor necrosis factor-alpha (TNF-α). Immunohistochemical staining was used to detect expression of ADA and CD73 in synovial tissue. Repeated EA treatment on CIA resulted in the persistence of high concentrations of adenosine in peripheral blood, significantly reduced pathological scores, TNF-α mRNA concentrations, and synovial hyperplasia. Importantly, EA treatment led to a significant increase in CD73 mRNA levels in peripheral blood but was associated with a decrease of CD73 immunostaining in synovial tissue. In addition, EA treatment resulted in a significant decrease of both ADA mRNA levels in peripheral blood and ADA immunostaining in synovial tissue. Thus, repeated EA treatment exerts an anti-inflammatory and immunoregulatory effect on CIA by increasing the concentration of adenosine. The mechanism of EA action may involve the modulation of CD73 and ADA expression levels.

Serum Adenosine Deaminase as Inflammatory Marker in Rheumatoid Arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a prototypical inflammatory joint disease. The degree of inflammation is reflected in the extent of joint damage, which further has influence on the quality of life of patients with RA, including risk of atherosclerosis. Hence, besides clinical indices, estimation of degree of inflammation using biochemical markers helps in effecting optimum treatment strategies. C-reactive protein (CRP) is established as an inflammatory marker in patients with RA. Adenosine deaminase (ADA), an enzyme of purine metabolism is considered as a marker of cell mediated immunity and has also been suggested as a marker of inflammatory process in RA. The present study attempts to study the efficacy of serum ADA activity as an inflammatory marker in RA.

MATERIALS AND METHODS

Forty six RA patients and forty six age and sex matched healthy controls were included in the study. ADA activity and high sensitivity C-reactive protein (hsCRP) levels in serum were measured in all the subjects. Statistical analyses were done using Medcalc statistical software version 12.2.2.

RESULTS

ADA activity and hsCRP levels were increased in RA patients compared to controls (p<0.0001 and 0.0001 respectively). Significant positive correlation was obtained between hsCRP and ADA in patients (r=0.316, p=0.033). Receiver operating characteristic (ROC) curve analysis revealed statistically significant area under curve (AUC) for ADA that is comparable to that obtained for hsCRP (0.776, p<0.0001 for ADA, 0.726, p<0.0001 for hsCRP). Similar diagnostic utility was obtained with ROC generated cut-off value of 25.3 IU/L (82.6% sensitivity and 65.2% specificity) and with control mean value of 23.48 IU/L (86.96% sensitivity and 54.35% specificity) for ADA.

CONCLUSION

Findings of the present study indicate the importance of ADA as a marker of inflammation. Considering the higher sensitivity obtained, we propose control mean (23.48 IU/L) as a cut-off for serum ADA activity as an inflammatory marker. Owing to the simplicity and also the cost effectiveness of ADA assay, ADA may be recommended as a marker of inflammation in patients with RA. However, further larger and well controlled studies are needed to establish its role as inflammatory marker.

Serum Adenosine Deaminase Level is High But Not Related with Disease Activity Parameters in Patients with Rheumatoid Arthritis

Serum adenosine deaminase (ADA) has been previously proposed to predict disease activity in patients with rheumatoid arthritis (RA). The aim of this study was to investigate the level of serum ADA, and the relationship between ADA and disease activity markers, in a group of patients with RA.

A hundred and 10 patients with a diagnosis of RA were recruited from outpatient clinic of Rheumatology Unit. Demographic properties comprising age, gender, disease duration and drugs were recorded. Disease activity based on disease activity score (DAS)28-erythrocyte sedimentation rate (ESR) and DAS28- C reactive protein (CRP,) ESR, CRP levels, as well as pain by visual analog scale and rheumatoid factor (RF) were recorded. Serum ADA levels (IU/L) were determined in all RA patients and in 55 age and sex similar healthy control subjects.

Ninety-six female and 14 male RA patients with a mean age of 54.32±11.51, and with a mean disease duration of 11.5±9.13 years were included to the study. The control group comprised of 48 female and 7 male healthy subjects. 35.5% of the patients were on methotrexate (MTX) and 64.5% of patients were on combined DMARDs or combined MTX and anti-TNF therapies. The mean serum ADA level was statistically higher in RA patients than in control subjects (27.01±10.6 IU/L vs 21.8 ±9.9 IU/L). The mean values of ESR (23.2±14.8 mm/h), CRP (1.71±1.11mg/dL), pain by VAS (37.2±27.1), DAS28-ESR (2.72±0.77), DAS28 CRP (1.37±0.5) were not correlated with ADA levels (p>0.05).

Our results have shown that serum ADA levels are higher in RA patients than in controls but were not related with any of the disease activity markers. We conclude that ADA in the serum may not be a reliable biochemical marker to predict disease activity in patients with RA.