The antioxidants adiponectin, total radical-trapping antioxidant parameter, sulfhydryl groups, zinc, and soluble tumor necrosis factor receptor 2 all play a role in the pathophysiology of multiple sclerosis.
Andrea Name Colado Simao, PhD
Results from a study of diagnostic biomarkers revealed that lowered levels of total radical-trapping antioxidant parameter (TRAP), adiponectin, zinc, and soluble tumor necrosis factor (TNF)-α receptor (sTNFR) 2 are associated with the disease activity of multiple sclerosis (MS).
Notably, these antioxidants were deemed more important biomarkers than TNF-α signaling and nitro-oxidative biomarkers.
The study, conducted by Edna Maria Vissoci Reiche, MD, of the and colleagues, examined 174 patients with MS, including 5 with clinically isolated syndrome (CIS), 144 with relapse-remitting MS (RRMS), and 25 with progressive clinical forms of MS (ProgMS). In total, 5 of those patients had primary progressive MS (PPMS) and 20 had secondary progressive MS (SPMS).
Vissoci Reiche and colleagues aimed to evaluate the plasma levels of TNF, sTNFR1, sTNFR2, adiponectin, hydroperoxides, advanced oxidation protein products (AOPP), and nitric oxide metabolites. Additionally, investigators observed total plasma antioxidant capacity using the TRAP, SH groups, and serum levels of zinc.
Patients were treated with a mix of either interferon (IFN)-β (n = 104), glatiramer acetate (n = 45), natalizumab (n = 10), glucocorticoids (n = 28), and fingolimod (n = 1). Investigators also enrolled 182 healthy individuals as controls for the study. Patients with MS and their matched controls filled out a standard questionnaire at the beginning of the study to record baseline characteristics.
Using the immunofluorometric assay, investigators determined plasma levels of TNF-A, sTNFR1, and sTNFR2. To determine adiponectin plasma levels, patients used a sandwich enzyme-linked immunosorbent assay (ELISA, Duo Set, R&D 207 System, Minneapolis, USA). Investigators used nitric oxide metabolites (NOx), nitrites (NO2), and nitrates (NO3) to estimate nitric oxide (NO). Total plasma antioxidant capacity was determined using the TRAP method. Notably, SH groups used a spectrophotometric assay based on 2,2-dithiobisnitrobenzoic acid (DTNB) for evaluation.
Significant predictors and confidence intervals were based on receiver operating characteristic (ROC). Using the ROC curve analysis, investigators calculated the area under the ROC (AUC/ROC).
The data revealed that patients with MS all had lowered levels of TRAP, zinc, adiponectin, and SH groups (all P = .001). Patients with this combination of antioxidants were correctly classified in 95.5% of cases, with a sensitivity of 95.7% and specificity of 95.1%. Investigators noted a .986 (+0.005) area under the curve (AUC)/receiver operating characteristic (ROC) curve based on these 4 antioxidants. Additionally, those with that combination of antioxidants displayed higher levels of AOPP (P = .041), NOx (P = .046), TNF-A (P <.001), and sTNFR2 (P <.001) than controls.
In a reran analysis that included sTNFR2, data demonstrated the best prediction for MS diagnosis (x2 = 162.29; df = 5; P <.001; Nagelkerke = .919). In that analysis, 97.4% of subjects were correctly classified with sensitivity of 98.7% and specificity of 91.7%. Notably, the AUC/ROC was 0.990 (+0.006) for patients with these 5 variables.
When examining possible effects of MS treatment in regression #1, investigators noted that glucocorticoids (F = 0.84; df = 7/246; P = .552), glatiramer acetate (F = .44, df = 7/246, P = .875), IFN-β (F = 0.55; df = 7/246; P = .797), and natalizumab (F = .30; df = 7/246; P = .954) all had no significant impact on the results of the study. During the general linear model (GLM), investigators noted a significant association between MS and an increase in TNF-α related variables. Glatiramer acetate (F = 0.23; df = 3/193; P = .876), IFN-β (F = 0.22; df = 3/193; P = .884), and natalizumab (F = 2.42; df = 3/193; P = .068) all showed no significant effect on MS treatment analysis.
“To our knowledge, this is the first report demonstrating that a combination of aforementioned biomarkers, including adiponectin, TRAP, SH groups, zinc, and sTNFR2, may be useful for MS diagnosis with high sensitivity, specificity, and accuracy. Therefore, this panel of biomarkers could be incorporated in the diagnostic biomarkers for MS in combination with clinical and radiological disease diagnostic criteria to improve the sensitivity and specificity of diagnosis,” the study authors concluded.
Mezzaroba L, Simao AC, Oliveira SR, et al. Antioxidant and anti-inflammatory diagnostic biomarkers in multiple sclerosis: a machine learning study. Mol Neurobiol (2020).doi : 10.1007/s12035-019-01856-7.