Tracking the Stability of Clinically Relevant Blood Plasma Proteins with Delta-S-Cys-Albumin-A Dilute-and-Shoot LC/MS-Based Marker of Specimen Exposure to Thawed Conditions

Markers of Endothelial Injury in Extracorporeal Membrane Oxygenation: A New Risk Assessment Method

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) has become more widely used in recent years. However, ECMO remains a resource-intensive modality, and identifying patients most likely to benefit from it can be a complex task. Few methods exist to help risk stratify potential ECMO patients. Syndecan-1 (SDC-1) and soluble thrombomodulin (sTM) are markers of endothelial dysfunction and are used as a sign of disease severity in various forms of trauma. Our study aims to evaluate the association between precannulation levels of SDC-1 and sTM with mortality, current scoring systems, and their ability to predict mortality on ECMO.

METHODS

Patients initiated on venoarterial ECMO were retrospectively analyzed. Clinical data were collected, and precannulation Acute Physiology and Chronic Health Evaluation scores were calculated. Blood samples from precannulation collection were assayed for SDC-1 and sTM by enzyme linked immunosorbent assay. The primary outcome was mortality on ECMO.

RESULTS

Thirty-four patients were included in the analysis. Most were male (76.5%), with a median age of 61.5 y and body mass index of 28.2. Overall mortality was 61.7%. sTM was significantly higher in patients who died on venoarterial ECMO compared to those who lived. Pre-SDC-1 level of ≥951 ng/mL is marginally predictive of a higher mortality risk (area under the receiver operating characteristic curve 0.70; P = 0.070). Pre-sTM levels of ≥5348 pg/mL predicted mortality (area under the receiver operating characteristic curve 0.89; P = 0.003).

CONCLUSIONS

SDC-1 and sTM are associated with a higher mortality risk in patients on ECMO. These biomarkers may be a valuable addition to current scoring systems. Furthermore, more work should focus on characterizing the effects of cardiogenic shock on the endothelium.

Delta-S-Cys-Albumin as a Marker of Pediatric Biospecimen Integrity

Blood plasma storage is a crucial element of pediatric biobanking. Improperly stored or handled specimens (e.g., at > -30°C) can result in altered biomolecular compositions that no longer reflects in vivo reality. We report application of a previously developed assay in adults-the ΔS-Cys-Albumin assay, which facilitates estimation of plasma and serum exposure to thawed conditions-to a population of pediatric EDTA plasma samples from patients aged 3-18 years to determine the assay's applicability, estimate its reference range for pediatric samples, and assess the impact of pre-centrifugation delay at 0°C. In addition, the effect of plasma thawed-state exposure to a range of times at 23°C, 4°C, and -20°C on ΔS-Cys-Albumin was evaluated. Using 98 precollected and processed pediatric EDTA plasma specimens, no difference was found in ΔS-Cys-Albumin under conditions of pre-centrifugation delay for up to 10 hours at 0°C. This lack of change allowed us to estimate a pediatric reference range for ΔS-Cys-Albumin of 7.0%-22.5% (mean of 12.8%) with a modest Pearson correlation between ΔS-Cys-Albumin and age (p = 0.0037, R2 = 0.29). ΔS-Cys-Albumin stability in six specimens at 23°C, 4°C, and -20°C was also evaluated. Plateaus in the decay curves were reached by 1 day, 7 days, and 14-28 days at these respective temperatures. The estimated pediatric reference range observed in children was lower than that previously observed in 180 adults of 12.3%-30.6% (mean of 20.0%), and the slope of the age correlation in children was twice as steep as that from adults. ΔS-Cys-Albumin decay curves at 23°C, 4°C, and -20°C were similar to those previously observed in adults. The data reported here support the use of ΔS-Cys-Albumin in evaluating the integrity and overall exposure of pediatric EDTA plasma specimens to thawed conditions. In doing so, they add an important quality control tool to the biobanker's arsenal.

Serotonin: A new super effective functional monomer for molecular imprinting. The case of TNF-α detection in real matrix by Surface Plasmon Resonance

Molecular imprinting and related technologies are becoming increasingly appreciated in bioanalysis and diagnostic applications. Among the imprinted polymers, we have already demonstrated that the endogenous neurotransmitters (NTs) dopamine (DA) and norepinephrine (NE) can be efficiently used as natural and sustainable monomers to straightforwardly design and synthesize a new generation of green and "soft" Molecularly Imprinted BioPolymers (MIBPs). Here, we demonstrated for the first time the ability of a further NT, i.e., serotonin (SE), in forming adhesive imprinted nanofilms coupled to label-free optical biosensing. Its imprinting efficiency is compared with those obtained with PDA and PNE. As a model study, tumor necrosis factor-alpha (TNF-α) was selected as a biomolecular target of interest in clinical diagnostics. The biomimetic receptor was coupled to Surface Plasmon Resonance (SPR), and TNF-α detection was performed in label-free and real-time manner both in buffer and biological matrices, i.e. synovial fluid and human serum. The results indicate that, under the same imprinting and binding conditions, the analytical performances of PSE are impressively superior to those of PDA and PNE. The PSE-based MIBP was able to detect TNF-α in human matrices with a good sensitivity, selectivity, and repeatability.