New technologies around biomarkers and their interplay with drug development

Quantification of Alpha-Synuclein in Biological Fluids by Electrochemiluminescence-Based Detection

Several potential marker candidates for Parkinson's disease (PD) in cerebrospinal fluid (CSF) have been identified. These include α-synuclein, a major constituent of the intracellular aggregates Lewy bodies, a neuropathological hallmark of PD, and others. The extracellular presence of α-synuclein in blood, CSF, saliva, and conditioned media motivated the hypothesis that the quantification of CSF α-synuclein is a biomarker for α-synuclein-related disorders. We here describe the development of an electrochemiluminescence-based assay by conversion of an established ELISA for quantification of α-synuclein. The assay not only works with CSF but can also be used to quantify α-synuclein in different biological fluids, i.e., whole blood and blood products, saliva, as well as brain homogenates and cell culture material.

Biomarkers intersect with the exposome

The exposome concept promotes use of omic tools for discovering biomarkers of exposure and biomarkers of disease in studies of diseased and healthy populations. A two-stage scheme is presented for profiling omic features in serum to discover molecular biomarkers and then for applying these biomarkers in follow-up studies. The initial component, referred to as an exposome-wide-association study (EWAS), employs metabolomics and proteomics to interrogate the serum exposome and, ultimately, to identify, validate and differentiate biomarkers of exposure and biomarkers of disease. Follow-up studies employ knowledge-driven designs to explore disease causality, prevention, diagnosis, prognosis and treatment.

Metabolomic Study of a Rat Fever Model Induced with 2,4-Dinitrophenol and the Therapeutic Effects of a Crude Drug Derived from Coptis chinensis

This study describes the metabonomics of fevers in animal models and the therapeutic effects of Rhizoma coptidis extract (RCE) on them. The rat urinary samples were analyzed by UPLC/ ESI–Q-TOF/MS, combined with principal component analysis (PCA). Nine ions were chosen to characterize the similarities and differences in the responses to fever. The ion at m/z 206.0278 was unambiguously identified to be xanthurenic acid. This study demonstrated that the metabonomic approach can readily distinguish between febrile and healthy individuals. This data support the contention that the metabonomic approach represents a promising new technology for the development of rapid-throughput in vivo fever screening. Furthermore, this approach can detect the interfering effects of RCE. This investigation has led the authors to believe that metabonomics is a valid approach for explaining the therapeutic effects of traditional Chinese medicine on fevers.

Development of electrochemiluminescence-based singleplex and multiplex assays for the quantification of α-synuclein and other proteins in cerebrospinal fluid

The need for improved diagnostic accuracy and markers of progression in neurodegenerative diseases motivates the identification of objective biomarkers as well as optimized assays for their quantification. Several potential marker candidates for Parkinson's disease (PD) in cerebrospinal fluid have been identified. These include α-synuclein, a major constituent of the intracellular aggregates. We give a general overview and details of our experience in converting established enzyme-linked immunoabsorbent assays (for α-synuclein and other proteins) onto an electrochemiluminescence-based platform as well as considerations on multiplexing different assays for PD.

Carbon nanoparticles as detection labels in antibody microarrays. Detection of genes encoding virulence factors in Shiga toxin-producing Escherichia coli

The present study demonstrates that carbon nanoparticles (CNPs) can be used as labels in microarrays. CNPs were used in nucleic acid microarray immunoassays (NAMIAs) for the detection of different Shiga toxin-producing Escherichia coli (STEC) virulence factors: four genes specific for STEC (vt1, vt2, eae, and ehxA) and the gene for E. coli 16S (hui). Optimization was performed using a Box-Behnken design, and the limit of detection for each virulence factor was established. Finally, this NAMIA using CNPs was tested with DNA from 48 field strains originating from cattle feces, and its performance was evaluated by comparing results with those achieved by the reference method q-PCR. All factors tested gave sensitivity and specificity values higher than 0.80 and efficiency values higher than 0.92. Kappa coefficients showed an almost perfect agreement (k > 0.8) between NAMIA and the reference method used for vt1, eae, and ehxA, and a perfect agreement (k = 1) for vt2 and hui. The excellent agreement between the developed NAMIA and q-PCR demonstrates that the proposed analytical procedure is indeed fit for purpose, i.e., it is valuable for fast screening of amplified genetic material such as E. coli virulence factors. This also proves the applicability of CNPs in microarrays.

Biomarkers of immunotoxicity for environmental and public health research

The immune response plays an important role in the pathophysiology of numerous diseases including asthma, autoimmunity and cancer. Application of biomarkers of immunotoxicity in epidemiology studies and human clinical trials can improve our understanding of the mechanisms that underlie the associations between environmental exposures and development of these immune-mediated diseases. Immunological biomarkers currently used in environmental health studies include detection of key components of innate and adaptive immunity (e.g., complement, immunoglobulin and cell subsets) as well as functional responses and activation of key immune cells. The use of high-throughput assays, including flow cytometry, Luminex, and Multi-spot cytokine detection methods can further provide quantitative analysis of immune effects. Due to the complexity and redundancy of the immune response, an integrated assessment of several components of the immune responses is needed. The rapidly expanding field of immunoinformatics will also aid in the synthesis of the vast amount of data being generated. This review discusses and provides examples of how the identification and development of immunological biomarkers for use in studies of environmental exposures and immune-mediated disorders can be achieved.

Immunoaffinity capillary electrophoresis as a powerful strategy for the quantification of low-abundance biomarkers, drugs, and metabolites in biological matrices

In the last few years, there has been a greater appreciation by the scientific community of how separation science has contributed to the advancement of biomedical research. Despite past contributions in facilitating several biomedical breakthroughs, separation sciences still urgently need the development of improved methods for the separation and detection of biological and chemical substances. In particular, the challenging task of quantifying small molecules and biomolecules, found in low abundance in complex matrices (e.g., serum), is a particular area in need of new high-efficiency techniques. The tandem or on-line coupling of highly selective antibody capture agents with the high-resolving power of CE is being recognized as a powerful analytical tool for the enrichment and quantification of ultra-low abundance analytes in complex matrices. This development will have a significant impact on the identification and characterization of many putative biomarkers and on biomedical research in general. Immunoaffinity CE (IACE) technology is rapidly emerging as the most promising method for the analysis of low-abundance biomarkers; its power comes from a three-step procedure: (i) bioselective adsorption and (ii) subsequent recovery of compounds from an immobilized affinity ligand followed by (iii) separation of the enriched compounds. This technology is highly suited to automation and can be engineered to as a multiplex instrument capable of routinely performing hundreds of assays per day. Furthermore, a significant enhancement in sensitivity can be achieved for the purified and enriched affinity targeted analytes. Thus, a compound that exists in a complex biological matrix at a concentration far below its LOD is easily brought to well within its range of quantification. The present review summarizes several applications of IACE, as well as a chronological description of the improvements made in the fabrication of the analyte concentrator-microreactor device leading to the development of a multidimensional biomarker analyzer.