Abstrait

Development and clinical validation of antioxidants based dried blood spots assay - Status as early biochemical marker for rare genetic disorders in Neonates.

Shyama Subramaniam1, Samu Subramaniam 2*, Subhasree. C.R.3, Arasar Seeralar. A.T.4

Introduction: The present study is to investigate the total antioxidant activity (TAC) in suspected neonates of inborn errors of metabolism with high risk, moderate risk and low risk. Dried blood spots have potential use in remote health applications for individual and population diagnosis and can enable epidemiological surveillance for known and unknown diseases. Dried blood spot sampling is most common method for collection, storing, transporting and analyzing a variety of human body fluids.

Materials and methods: After performing, while newborn screening is early period, the balance residual samples were used for specific secondary research studies with patient consent. Here we are using the secondary studies of DBS for total antioxidant activity as one of the biomarkers to find out the disease condition. TAC was evaluated in 449 risk subjects and 531 control neonates including high, moderate, low risk and healthy individuals. The risk variables were included birth weight, APGAR score, gestational age and previous complications of pregnancy. DBS -TAC method, is to elute sample by using phosphate buffered saline. After sample preparation, TAC by using FRAP assay (ferric reducing antioxidant power assay) were estimated by among four groups with risk indicators.

Results: Statistical comparisons and correlations at 5% level of significance were determined. The mean TAC concentration was significantly elevated in high risk group. The mean TAC for low, moderate and high-risk group (Mean ± SD values were 954.8 ± 132.2 μmol/L, 700.4 ± 100.6 μmol/L and 510.4 ± 110 μmol/L respectively) patients were significantly reduced compared with control group (Mean ± S.D. valued was 1017.3 ± 122.2 μmol/L) (p < 0.05). Likely the SOD, Vit C, Vit E and MDA also were estimated.

Discussion: DBS-TAC can be used as early biochemical marker for oxidative stress in high risk for IEM (Inborn errors of metabolism) which may result in reduced tissue damage by free radicals and help to monitor and optimize antioxidant therapy in such high risk neonates.

Conclusion: FRAP assay is presented as a novel method of assessing total antioxidant capacity and is considered as a useful indicator of the body's antioxidant status to counteract the oxidative damage due to ROS. The advantage of the FRAP assay is in being fast, easy to handle, with highly reproducible results. A significantly lower DBS TAC concentration in the IEM high risk patients compared to controls reflects a lower total antioxidant capacity. Thus, TAC may be useful as an early marker of oxidative stress to monitor and optimize antioxidant therapy as an adjunct in the management of IEM patients.