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. 2021 Dec;15(18):1721-1732.
doi: 10.2217/bmm-2021-0284. Epub 2021 Oct 22.

Characterization and standardization of multiassay platforms for four commonly studied traumatic brain injury protein biomarkers: a TBI Endpoints Development Study

George Anis Sarkis  1 , Tian Zhu  2   3   4 , Zhihui Yang  2 , Xue Li  2   4 , Yuan Shi  3   4 , Richard Rubenstein  5 , Richard A Yost  1 , Geoffrey T Manley  6 , Kevin K Wang  2   7
Affiliations

Characterization and standardization of multiassay platforms for four commonly studied traumatic brain injury protein biomarkers: a TBI Endpoints Development Study

George Anis Sarkis et al. Biomark Med. 2021 Dec.

Abstract

Aim: There is a critical need to validate biofluid-based biomarkers as diagnostic and drug development tools for traumatic brain injury (TBI). As part of the TBI Endpoints Development Initiative, we identified four potentially predictive and pharmacodynamic biomarkers for TBI: astroglial markers GFAP and S100B and the neuronal markers UCH-L1 and Tau. Materials & methods: Several commonly used platforms for these four biomarkers were identified and compared on analytic performance and ability to detect gold standard recombinant protein antigens and to pool control versus TBI cerebrospinal fluid (CSF). Results: For each marker, only some assay formats could differentiate TBI CSF from the control CSF. Also, different assays for the same biomarker reported divergent biomarker values for the same biosamples. Conclusion: Due to the variability of TBI marker assay in performance and reported values, standardization strategies are recommended when comparing reported biomarker levels across assay platforms.

Keywords: GFAP; S100B; Tau; UCH-L1; biomarker qualification; neurodegeneration; protein biomarkers; traumatic brain injury.

Plain language summary

Lay abstract Traumatic brain injury (TBI) is a leading cause of mortality and morbidity around the world. There is a critical need to validate biofluid-based biomarker tests as diagnostic and drug development tools. For this study, we focused on four brain-derived proteins called GFAP, S100B, UCH-L1 and Tau. To measure these biomarker proteins in human biofluid, one relies on either commercial or home-brew assays. Here, we attempted to compare the performance of 2–4 assay formats for each biomarker. We compared their assay sensitivity, ability to detect ‘gold standard’ protein analyte we procured, as well as the ability to differentiated pooled TBI cerebrospinal fluid from healthy control cerebrospinal fluid. We found that there are high variabilities among TBI marker assays in assay performance, reported biomarker values and ability to differentiate TBI versus control biofluid. Thus, a standardization strategy is needed when comparing reported biomarker levels across assay platforms.

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Conflict of interest statement

Financial & competing interests disclosure

This study is mainly supported by DOD TBI Endpoints Development (TED) Seed Project TED1506/ W81XWH-14-2-0176 (KK Wang) and DOD Grant W81XWH-14-2-0176 (KK Wang and Principal Investigator GT Manley). The study is also supported in part by NIH 1U01 NS086090-01 (KK Wang, overall Principal Investigator GT Manley) and DOD-Army grant W81XWH-14-2-0166 (R Rubenstein). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Figures

Figure 1.
Figure 1.. Human traumatic brain injury biomarker antigen used as a gold standard solution for this study.
Left: source of the protein antigen and properties. Right: purity quality control of the four protein biomarker standards (UCH-L1, GFAP, S100B and Tau-441). First batch: SDS (10–20%) gradient polyacrylamide. Gel electrophoresis was performed followed by Coomassie blue R250 staining. Purity is 93–95% by densitometry analysis.
Figure 2.
Figure 2.. Standard curve for three UCH-L1 assays based on vendors; standard and UF’s NNBR gold standard.
(Mean + SD are shown, n = 3). SD: Standard deviation.
Figure 3.
Figure 3.. Standard curve for three GFAP assays based on vendors; standard and UF’s NNBR gold standard.
(Mean + SD are shown, n = 3). SD: Standard deviation.
Figure 4.
Figure 4.. Standard curve for two S100B assays based on vendors; standard and UF’s NNBR gold standard.
(Mean + SD are shown, n = 3). SD: Standard deviation.
Figure 5.
Figure 5.. Standard curve for four Tau assays based on vendors; standard and UF’s NNBR gold standard.
(Mean + SD are shown, n = 3). SD: Standard deviation; SOFIA: Surround optical fiber immunosorbent assay.
See this image and copyright information in PMC

References

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