High Resolution Discovery Proteomics Reveals Candidate Disease Progression Markers of Alzheimer's Disease in Human Cerebrospinal Fluid.

Disease modifying treatments for Alzheimer's disease (AD) constitute a major goal in medicine. Current trends suggest that biomarkers reflective of AD neuropathology and modifiable by treatment would provide supportive evidence for disease modification. Nevertheless, a lack of quantitative tools to assess disease modifying treatment effects remains a major hurdle.

Development and fit-for-purpose validation of a LC-MS/MS assay for fibrinogen peptide A quantitation in human plasma.

Background: Fibrinopeptide A (FPA) is a plasma peptide, formed by the action of thrombin on fibrinogen during clog formation. FPA represents a direct indicator of thrombin activity and could potentially be used as a biomarker for anti-thrombotic therapy development. Results/Methodology: A LC-MS/MS assay with a high throughput solid phase extraction procedure was developed and validated to measure FPA in plasma.

Quantification of tau in cerebrospinal fluid by immunoaffinity enrichment and tandem mass spectrometry.

Background: Cerebrospinal fluid (CSF) tau is a common biomarker for Alzheimer disease (AD). Measurements of tau have historically been performed using immunoassays. Given the molecular diversity of tau in CSF, the selectivity of these immunoassays has often been questioned.

An ultrasensitive method for the quantitation of active and inactive GLP-1 in human plasma via immunoaffinity LC-MS/MS.

Background: Measuring endogenous levels of incretin hormones, like GLP-1, is critical in the development of antidiabetic compounds. However, the assays used to measure these molecules often have analytical issues.

Results: We have developed an ultrasensitive, highly-selective immunoaffinity LC-MS/MS (IA LC-MS/MS) assay capable of quantitating endogenous levels of active (7-36 amide) and inactive (9-36 amide) GLP-1 in human plasma.

Development and validation of a clinical trial patient stratification assay that interrogates 27 mutation sites in MAPK pathway genes.

Somatic mutations identified on genes related to the cancer-developing signaling pathways have drawn attention in the field of personalized medicine in recent years. Treatments developed to target a specific signaling pathway may not be effective when tumor activating mutations occur downstream of the target and bypass the targeted mechanism. For instance, mutations detected in KRAS/BRAF/NRAS genes can lead to EGFR-independent intracellular signaling pathway activation.

Tissue microarrays: leaping the gap between research and clinical adoption.

The use of tissue microarrays (TMAs) in the preclinical and translational research settings has become ubiquitous as they allow for high-throughput in situ biomarker analysis of hundreds of patient samples, with time and cost efficiency. Coupled with advanced imaging and image-analysis technologies that allow for objective and standardized biomarker expression assessment, TMAs have become critical tools for the development and validation of clinically meaningful biomarker diagnostic assays. However, their diagnostic use in the clinical laboratory setting is limited due to the need for conventional whole-section tissue assessment used for routine diagnostic purposes.

Circulating miR-122 as a potential biomarker of liver disease.

Aim: Expression profiles indicate that miR-122 is specifically and abundantly expressed in liver. This study sought to determine miR-122 plasma concentrations in 15 apparently healthy subjects and 30 patients with liver disease, and clarify whether plasma miR-122 correlates with ALT.

Materials & Methods: miR-122 was measured by quantitative PCR in healthy volunteers and patients with liver disease.

Quantitative determination of human interleukin 22 (IL-22) in serum using Singulex-Erenna® technology.

Interleukin-22 (IL-22) is a key mediator of inflammatory processes associated with diseases such as psoriasis, inflammatory bowel disease and rheumatoid arthritis. The measurement of this cytokine in human plasma may provide insight into safety, pharmacodynamics and efficacy of drugs targeting inflammatory pathways. However, commonly used immunoassays are not sufficiently sensitive to measure baseline concentrations of IL-22.

Development and validation of an ultra-sensitive method for the measurement of plasma renin activity in human plasma via LC-MS/MS.

Background: Renin catalyzes the conversion of angiotensinogen to angiotensin I (Ang I), the first and rate-limiting step in the renin-angiotensin-aldosterone system. Plasma renin activity (PRA) is an important target engagement biomarker in the clinical development of renin inhibitors. We have developed and validated an improved PRA assay that incorporates an Ang I trapping antibody followed by extraction and quantification of Ang I using a highly sensitive and specific LC-MS/MS method.

Development and validation of a LC/MS/MS method for 6-keto PGF1α, a metabolite of prostacyclin (PGI₂).

A sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the quantitation of 6-keto PGF(1α) in human urine and plasma. Prostacyclin (PGI(2)) is a locally acting prostanoid, which mediates vasorelaxation and inhibition of platelet aggregation. 6-Keto PGF(1α) is the most-immediate metabolite of PGI(2).

Plasma MicroRNAs as sensitive and specific biomarkers of tissue injury.

Background: MicroRNAs (miRNAs) are endogenous, small noncoding RNAs. Because of their size, abundance, tissue specificity, and relative stability in plasma, miRNAs hold promise as unique accessible biomarkers to monitor tissue injury.

Methods: We investigated the use of liver-, muscle- and brain-specific miRNAs as circulating biomarkers of tissue injury.

Biomarkers of tissue injury.

Biomarkers of tissue injury have evolved empirically over the last 50-100 years. With the advent of immunoassays and discovery tools such as RNA expression and proteomics, more systematic approaches to the discovery of biomarkers can be expected in the future. This review discusses the evolution of biomarkers of muscle, liver, heart and brain injury and illustrates that a modern discovery tool, such as mRNA profiling, would have predicted the biomarkers for cardiac injury (heart attacks) that actually evolved over 50 years by empiric approaches.

Characterization of etoricoxib, a novel, selective COX-2 inhibitor.

Etoricoxib is a potent selective COX-2 inhibitor in man. Ex vivo whole-blood assays assessed COX-2 inhibition after oral administration of etoricoxib in single (5-500 mg) and multiple (25-150 mg) once-daily doses to healthy human subjects. A separate study examined ex vivo gastric mucosal PGE2 synthesis after etoricoxib (120 mg qd), naproxen (500 mg bid), or placebo for 5 days.