Development of an enzyme-linked immunosorbent assay for equine neutrophil elastase measurement in blood: Preliminary application to colic cases

Effects of High-Speed Training on Messenger RNA Expression in Two-Year-Old Thoroughbred Racehorses

Accumulating high-speed exercise has been identified as a significant risk factor for catastrophic injuries in racing Thoroughbreds. Injuries, regardless of severity, are a main cause of withdrawal from the racing industry, raising animal welfare concerns and resulting in significant economic losses. While most of the current literature focuses on injuries incurred during racing rather than training, the present study aims to help fill this gap. As such, peripheral blood was collected weekly, prior to exercise or administration of medication, from eighteen, two-year-old Thoroughbreds throughout their first season of race training. Messenger RNA (mRNA) was isolated and used to analyze the expression of 34 genes via RT-qPCR. Statistical analysis of the noninjured horses (n = 6) showed that 13 genes were significantly correlated with increasing average weekly high-speed furlong performance. Additionally, there was a negative correlation for CXCL1, IGFBP3, and MPO with both cumulative high-speed furlongs and week of training for all horses. Comparison of both groups showed opposing correlations between the anti-inflammatory index (IL1RN, IL-10, and PTGS1) and average weekly high-speed furlong performance. Furthermore, evaluation of training effects on mRNA expression during the weeks surrounding injury, showed differences between groups in IL-13 and MMP9 at -3 and -2 weeks prior to injury. While some previously reported relationships between exercise adaptation and mRNA expression were not noted in this study, this may have been due to the small sample size. Several novel correlations, however, were identified and warrant further investigation as markers of exercise adaptation or potential risk for injury.

Multiplexed Single-Cell Leukocyte Enzymatic Secretion Profiling from Whole Blood Reveals Patient-Specific Immune Signature

Enzymatic secretion of immune cells (leukocytes) plays a dominant role in host immune responses to a myriad of biological triggers, including infections, cancers, and cardiovascular diseases. Current tools to probe these leukocytes inadequately profile these vital biomarkers; the need for sample preprocessing steps of cell lysis, labeling, washing, and pipetting inevitably triggers the cells, changes its basal state, and dilutes the individual cell secretion in bulk assays. Using a fully integrated system for multiplexed profiling of native immune single-cell enzyme secretion from 50 μL of undiluted blood, we eliminate sample handling. With a total analysis time of 60 min, the integrated platform performs six tasks of leukocyte extraction, cell washing, fluorescent enzyme substrate mixing, single-cell droplet making, droplet incubation, and real-time readout for leukocyte secretion profiling of neutrophil elastase, granzyme B, and metalloproteinase. We calibrated the device, optimized the protocols, and tested the leukocyte secretion of acute heart failure (AHF) patients at admission and predischarge. This paper highlights the presence of single-cell enzymatic immune phenotypes independent of CD marker labeling, which could potentially elucidate the innate immune response states. We found that patients recovering from AHF showed a corresponding reduction in immune-cell enzymatic secretion levels and donor-specific enzymatic signatures were observed, which suggests patient-to-patient heterogeneous immune response. This platform presents opportunities to elucidate the complexities of the immune response from a single drop of blood and bridge the current technological, biological, and medical gap in understanding immune response and biological triggers.

Effects of intra-articular administration of lidocaine, mepivacaine, and the preservative methyl parahydroxybenzoate on synovial fluid biomarkers of horses

OBJECTIVE

To compare the extent of inflammation and catabolic collagen response in the middle carpal joints (MCJs) of healthy horses following intra-articular injection of 2% lidocaine, 2% mepivacaine, lactated Ringer solution (LRS), or 0.1% methyl parahydroxybenzoate.

ANIMALS

17 adult horses.

PROCEDURES

In the first of 2 experiments, the left middle carpal joint (MCJ) of each of 12 horses was injected with 10 mL of 2% lidocaine (n = 3), 2% mepivacaine (3), or LRS (control; 6). After a 4-week washout period, the right MCJ of the horses that received lidocaine or mepivacaine was injected with 10 mL of LRS, and the right MCJ of horses that received LRS was injected with 10 mL of 2% lidocaine (n = 3) or 2% mepivacaine (3). In experiment 2, the left MCJ of each of 5 horses was injected with 10 mL of 0.1% methyl parahydroxybenzoate. After a 48-hour washout period, the right MCJ of each horse was injected with 10 mL of LRS. Synovial fluid (SF) samples were aseptically collected before and at predetermined times after each injection. Synovial fluid WBC count, neutrophil percentage, and total protein, neutrophil myeloperoxidase, neutrophil elastase, and Coll2-1 concentrations were compared among treatments.

RESULTS

Both lidocaine and mepivacaine induced SF changes indicative of inflammation and a catabolic collagen response, but the magnitude of those changes was more pronounced for lidocaine. Methyl parahydroxybenzoate did not cause any SF changes indicative of inflammation.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that mepivacaine was safer than lidocaine for intra-articular injection in horses.

Detection of human neutrophil elastase by aptamer affinity capillary electrophoresis coupled with laser-induced fluorescence using specified site fluorescently labeled aptamer

As a multifunctional serine protease, human neutrophil elastase (HNE) plays critical roles in a variety of physiopathological processes, such as acute lung injury, emphysema, atherosclerosis, and arthritis. The quantification of HNE is important in many applications. In this paper, we report an aptamer affinity capillary electrophoresis coupled with laser-induced fluorescence (CE-LIF) assay for detection of HNE using a tetramethylrhodamine (TMR)-labeled DNA aptamer probe. The affinity complex of HNE and DNA aptamer probe was well separated from the unbound aptamer probe in CE separation based on the difference of electrophoretic mobility. Broad complex peaks appeared due to possible multiple binding. The 45-mer aptamer having TMR labeling on the 40th T base was used as affinity probe, as larger complex peaks were obtained. We investigated the effects of various metal cations (Na⁺, K⁺, and Mg²⁺) in sample buffer on the binding of HNE and the aptamer in CE-LIF analysis. The presence of Na⁺, K⁺, or Mg²⁺ in sample buffer caused a decrease of complex peaks, and Mg²⁺ showed a larger effect. Under optimized conditions, this aptamer CE-LIF assay enabled the detection of HNE at 0.5 nM. This assay showed good specificity and allowed for detection of HNE spiked in diluted human serum sample. Graphical abstract The complex of HNE and DNA aptamer probe was isolated from the unbound aptamer probe in CE separation due to difference of electrophoretic mobility, allowing a CE-LIF assay for HNE.

Assessment of systemic inflammation by time-trends of blood granulocyte count and plasma myeloperoxidase and elastase concentrations following colic surgery in horses

OBJECTIVE

To determine changes in blood granulocyte counts and in plasma myeloperoxidase (MPO) and elastase (ELT) concentrations in surgical colic cases, and to determine the relationship between these changes and the surgical procedure performed, occurrence of postoperative ileus, and final outcome.

DESIGN

Prospective clinical study conducted over a 12-month period.

SETTING

University teaching hospital.

ANIMALS

Fifty-three horses undergoing emergency laparotomy and surviving at least 12 hours postoperatively.

INTERVENTIONS

Blood samples were taken before surgery, during surgery, at the recovery from anesthesia, and then serially until the 150th hour after the first blood sampling. Granulocyte counts were performed by an automated cell hematology analyzer. Specific ELISAs were performed for the MPO and ELT measurements. Mixed models were used to compare the time-trends of the 3 parameters.

MEASUREMENTS AND MAIN RESULTS

Taking all horses together, the time-trends of MPO and ELT were not significantly different from each other, but they were significantly different from the granulocyte time-trend. The type of surgical procedure did not influence the time-trends of the 3 parameters. Significant changes in the granulocyte time-trends were associated with postoperative ileus and outcome. Significant changes in the MPO time-trends were associated with outcome. The ELT time-trends were not influenced by ileus or outcome.

CONCLUSIONS

Granulocyte counts and MPO change over time and are related to the severity of the inflammatory reaction in surgical colic cases. These time-trends may allow evaluation of treatment efficacy in an effort to modulate excessive granulocyte activation and degranulation.

Effect of inhaled hydrosoluble curcumin on inflammatory markers in broncho-alveolar lavage fluid of horses with LPS-induced lung neutrophilia

Background

Horses commonly suffer from chronic respiratory disease and are also used in large animal models of spontaneous or induced airway inflammation. The anti-inflammatory properties of curcumin are largely described but its low bioavailability precludes its clinical use. NDS27, a lysin salt of curcumin incorporated in beta-cyclodextrine, has high bioavailability and can be administered by inhalation. The aim of this study was to investigate the effects of inhaled NDS27 on inflammatory cytokines and proteins in the broncho-alveolar lavage fluid using a model of neutrophilic airway inflammation.

Methods

Airway neutrophilia was induced in eight horses by inhalation of lipopolysaccharides (LPS). Horses were treated with either inhalation of NDS27 or with placebo in a randomized cross-over design. Broncho-alveolar lavages were performed 6 hours after stimulation with LPS. Percentage of neutrophils, concentrations of IL-1β, TNF-α, IL-6, Club cell secretory protein, myeloperoxidase (MPO) and elastase (ELT) concentrations were determined.

Results

LPS stimulation induced significant increases in neutrophil counts and concentrations of IL-6 (70.2 ± 66.0 pg/ml), TNF-α (43.9 ± 31.2 pg/ml), MPO (580.9 ± 327.0 ng/ml) and ELT (27.6 ± 16.7 ng/ml). Treatment with NDS27 significantly prevented the increase in active and total MPO (216.4 ± 118.1 ng/ml) and ELT (5.9 ± 3.2 ng/ml) while there was a trend towards reduced IL-6 concentration.

Conclusions

Results show that, although not reducing neutrophil recruitment, NDS27 largely abolishes LPS-induced neutrophil degranulation. Reduced levels of ELT and MPO, as well as reduced MPO activity may have beneficial effects via a reduced production of reactive oxygen species implicated in chronic inflammation and airway remodeling.

NDS27 combines the effect of curcumin lysinate and hydroxypropyl-β-cyclodextrin to inhibit equine PKCδ and NADPH oxidase involved in the oxidative burst of neutrophils

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The antioxidant effects of curcumin lysinate complexed with two cyclodextrins were compared.

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NDS27 is complexed with hydroxypropyl-β- and NDS28 with γ-cyclodextrin.

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NDS27 but not NDS28 inhibits translocation and activity of PKCδ and NADPH oxidase.

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NDS27 but not NDS28 improved the release of curcumin lysinate and its exchange with membrane lipids.

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NDS27 is a good candidate molecule to inhibit ROS production by neutrophils.

Polymorphonuclear neutrophils (PMNs) are involved in host defence against infections by the production of reactive oxygen species (ROS), but excessive PMN stimulation is associated with the development of inflammatory diseases. After appropriate stimuli, protein kinase C (PKC) triggers the assembly of NADPH oxidase (Nox2) which produces superoxide anion (O₂^•−), from which ROS derive. The therapeutic use of polyphenols is proposed to lower ROS production by limiting Nox2 and PKC activities. The purpose of this study was to compare the antioxidant effect of NDS27 and NDS28, two water-soluble forms of curcumin lysinate respectively complexed with hydroxypropyl-β-cyclodextrin (HPβCD) and γ-cyclodextrin (γ-CD), on the activity of Nox2 and PKCδ, involved in the Nox2 activation pathway. Our results, showed that NDS27 is the best inhibitor for Nox2 and PKCδ. This was illustrated by the combined effect of HPβCD and curcumin lysinate: HPβCD, but not γ-CD, improved the release of curcumin lysinate and its exchange against lipid or cholesterol as demonstrated by the lipid colouration with Oil Red O, the extraction of radical lipophilic probes recorded by ESR and the HPLC measurements of curcumin. HPβCD not only solubilised and transported curcumin, but also indirectly enhanced its action on both PKC and Nox2 activities. The modulatory effect of NDS27 on the Nox2 activation pathway of neutrophils may open therapeutic perspectives for the control of pathologies with excessive inflammatory reactions.

Aptamer-capture based assays for human neutrophil elastase

Human neutrophil elastase (HNE) is a multifunctional serine protease, involved in infection defense, inflammatory process regulation, and physiopathological processes of several diseases. We developed aptamer-capture based assays for human neutrophil elastase with different substrates and solid supports to meet different demands, such as simplicity, sensitivity, and high throughput. Aptamers against HNE were immobilized on magnetic beads or microplates as affinity ligands to capture HNE, and then the enriched HNE catalyzed the conversion of chromogenic substrates or fluorogenic substrates to products. The measurement of the generated enzymatic products enabled the final detection of HNE. In the assay using chromogenic substrates and aptamer modified magnetic beads, 0.4 pM HNE could be successfully detected. The sensitivity of the assay was further improved by using fluorogenic substrates, and a detection limit of HNE at 20 fM was achieved. The use of aptamer-coated microplates instead of aptamer modified magnetic beads in the assays also allowed the sensitive detection of HNE, offering advantages in fast sample handling and measurement. The established assays for HNE displayed good specificity, and proteins including serum albumin, transferrin, immunoglobulin G, thrombin, porcine pancreatic elastase, trypsin, proteinase K, chymotrypsin, lysozyme, cathepsin G, and proteinase 3 did not cause interference in the detection of HNE.