Utility, reliability and reproducibility of immunoassay multiplex kits

Highly sensitive blood-based biomarkers detection of beta-amyloid and phosphorylated-tau181 for Alzheimer's disease

Background

Plasma biomarker has the potential to be the reliable and propagable approach in the early stage diagnosis of Alzheimer's disease (AD). However, conventional methods appear powerless in the detection of these biomarkers at low concentrations in plasma. Here, we determined plasma biomarker concentrations of patients across the AD spectrum by an improved digital enzyme-linked immunosorbent assay (ELISA) technique. Confirms the predictive and diagnostic value of this method for AD patients and study the relationships between these biomarkers and cognitive status.

Methods

Plasma concentrations of amyloid-beta 40 (Aβ40), amyloid-beta 42 (Aβ42) and plasma phosphorylated tau at threonine 181 (p-tau181) were determined in 43 AD patients, 33 mild cognitive impairment (MCI) patients and 40 normal cognition (NC) subjects as healthy controls using the improved digital ELISA technique. In addition, all subjects were required to receive neuropsychological assessments.

Results

Plasma p-tau181 level showed certain discrepancies between NC and MCI (p < 0.05), AD (p < 0.01) groups. The level of plasma Aβ42 (p < 0.05) and Aβ40 (p < 0.01) was significantly different between AD and NC group. The p-tau181 level was able to distinguish AD (AUC = 0.8768) and MCI (AUC = 0.7932) from NC with higher accuracy than Aβ42/Aβ40 ratio (AUC = 0.8343, AUC = 0.6569). Both p-tau181 (CDR: r = 0.388 p < 0.001; MMSE: r = -0.394 p < 0.001) and Aβ42/Aβ40 ratio (CDR: r = -0.413 p < 0.001; MMSE: r = 0.358 p < 0.001) showed stronger positive correlation with clinical dementia rating (CDR) and mini mental state examination (MMSE) scores than Aβ42 (CDR: r = -0.280 p = 0.003; MMSE: r = 0.266 p = 0.005) or Aβ40 (CDR: r = 0.373 p < 0.001; MMSE: r = -0.288 p = 0.002) alone.

Conclusion

Plasma p-tau181 level and Aβ42/Aβ40 ratio showed promising values in diagnosis of AD and MCI. Our results indicate that this improved digital ELISA diagnosis approach can facilitate early recognition and management of AD and pre-AD patients.

Miniaturized microarray-format digital ELISA enabled by lithographic protein patterning

The search for reliable protein biomarker candidates is critical for early disease detection and treatment. However, current immunoassay technologies are failing to meet increasing demands for sensitivity and multiplexing. Here, the authors have created a highly sensitive protein microarray using the principle of single-molecule counting for signal amplification, capable of simultaneously detecting a panel of cancer biomarkers at sub-pg/mL levels. To enable this amplification strategy, the authors introduce a novel method of protein patterning using photolithography to subdivide addressable arrays of capture antibody spots into hundreds of thousands of individual microwells. This allows for the total sensor area to be miniaturized, increasing the total possible multiplex capacity. With the immunoassay realized on a standard 75x25 mm form factor glass substrate, sample volume consumption is minimized to <10 μL, making the technology highly efficient and cost-effective. Additionally, the authors demonstrate the power of their technology by measuring six secretory factors related to glioma tumor progression in a cohort of mice. This highly sensitive, sample-sparing multiplex immunoassay paves the way for researchers to track changes in protein profiles over time, leading to earlier disease detection and discovery of more effective treatment using animal models.

A Guide to Flow Cytometry: Components, Basic Principles, Experimental Design, and Cancer Research Applications

Flow cytometry (FCM) is a state-of-the-art technique for the qualitative and quantitative assessment of cells and other particles' physical and biological properties. These cells are suspended within a high-velocity fluid stream and pass through a laser beam in single file. The main principle of the FCM instrument is the light scattering and fluorescence emission upon the interaction of the fluorescent particle with the laser beam. It also allows for the physical sorting of particles depending on different parameters. A flow cytometer comprises different components, including fluidic, optics, and electronics systems. This article briefly explains the mechanism of all components of a flow cytometer to clarify the FCM technique's general principles, provides some useful guidelines for the proper design of FCM panels, and highlights some general applications and important applications in cancer research. © 2023 Wiley Periodicals LLC.

Dynamic immune markers predict HIV acquisition and augment associations with sociobehavioral factors for HIV exposure

Prior studies attempting to link biomarkers of immune activation with risk of acquiring HIV have relied on cross sectional samples, most without proximity to HIV acquisition. We created a nested case-control study within the Sabes study in Peru, and assessed a panel of plasma immune biomarkers at enrollment and longitudinally, including within a month of diagnosis of primary HIV or matched timepoint in controls. We used machine learning to select biomarkers and sociobehavioral covariates predictive of HIV acquisition. Most biomarkers were indistinguishable between cases and controls one month before HIV diagnosis. However, levels differed between cases and controls at study entry, months to years earlier. Dynamic changes in IL-2, IL-7, IL-10, IP-10 and IL-12, rather than absolute levels, jointly predicted HIV risk when added to traditional risk factors, and there was modest effect modification of biomarkers on association between sociobehavioral risk factors and HIV acquisition.

Kinetic characterization of SPR-based biomarker assays enables quality control, calibration free measurements and robust optimization for clinical application

Biomarker measurements are essential for the early diagnosis of complex diseases. However, many current biomarker assays lack sensitivity and multiplexing capacity, work in a narrow detection range and importantly lack real time quality control opportunities, which hampers clinical translation. In this paper, we demonstrate a toolbox to kinetically characterize a biomarker measurement assay using Surface Plasmon Resonance imaging (SPRi) with ample opportunities for real time quality control by exploiting quantitative descriptions of the various biomolecular interactions. We show an accurate prediction of SPRi measurements at both low and high concentrations of various analytes with deviations <5% between actual measurements and predicted measurement. The biphasic binding sites model was accurate for fitting the experimental curves and enables optimal detection of heterophilic antibodies, cross-reactivity, spotting irregularities and/or other confounders. The toolbox can also be used to create a (simulated) calibration curve, enabling calibration-free measurements with good recovery, it allows for easy assay optimizations, and could help bridge the gap to bring new biomarker assays to the clinic.

Highly accurate multiprotein detection on a digital ELISA platform

The emerging single-molecule detection platform digital enzyme-linked immunosorbent assay (ELISA) can detect numerous proteins simultaneously at serum concentrations as low as picograms per milliliter. We sought to improve cytokine detection with this platform to aid diagnosis of conditions such as allergy and asthma. We developed a multiple single-molecule detection digital ELISA approach, through the application of encoded magnetic microbeads to simultaneously detect three cytokines in one serum sample. We tested the approach's utility to distinguish asthma-related cytokines in children. Concentrations of interleukin-4 (IL-4) and IL-6 were significantly higher in children with asthma than in healthy controls, while the concentration of interferon-γ (IFN-γ) was significantly lower. Our method has higher accuracy than conventional methods, and our results indicate that the proposed improved high-sensitivity digital ELISA-based diagnosis approach can facilitate early detection and treatment of childhood asthma or related diseases.

Techniques for Profiling the Cellular Immune Response and Their Implications for Interventional Oncology

In recent years there has been increased interest in using the immune contexture of the primary tumors to predict the patient's prognosis. The tumor microenvironment of patients with cancers consists of different types of lymphocytes, tumor-infiltrating leukocytes, dendritic cells, and others. Different technologies can be used for the evaluation of the tumor microenvironment, all of which require a tissue or cell sample. Image-guided tissue sampling is a cornerstone in the diagnosis, stratification, and longitudinal evaluation of therapeutic efficacy for cancer patients receiving immunotherapies. Therefore, interventional radiologists (IRs) play an essential role in the evaluation of patients treated with systemically administered immunotherapies. This review provides a detailed description of different technologies used for immune assessment and analysis of the data collected from the use of these technologies. The detailed approach provided herein is intended to provide the reader with the knowledge necessary to not only interpret studies containing such data but also design and apply these tools for clinical practice and future research studies.

The Comparative Effect of Different Timings of Whole Body Cryotherapy Treatment With Cold Water Immersion for Post-Exercise Recovery

Despite several established benefits of Whole Body Cryotherapy (WBC) for post-exercise recovery, there is a scarcity of research which has identified the optimum WBC protocol for this purpose. This study investigated the influence of WBC treatment timing on physiological and functional responses following a downhill running bout. An additional purpose was to compare such responses with those following cold water immersion (CWI), since there is no clear consensus as to which cold modality is more effective for supporting athletic recovery. Thirty-three male participants (mean ± SD age 37.0 ± 13.3 years, height 1.76 ± 0.07 m, body mass 79.5 ± 13.7 kg) completed a 30 min downhill run (15% gradient) at 60% VO₂ max and were then allocated into one of four recovery groups: WBC1 (n = 9) and WBC4 (n = 8) underwent cryotherapy (3 min, −120°C) 1 and 4 h post-run, respectively; CWI (n = 8) participants were immersed in cold water (10 min, 15°C) up to the waist 1 h post-run and control (CON, n = 8) participants passively recovered in a controlled environment (20°C). Maximal isometric leg muscle torque was assessed pre and 24 h post-run. Blood creatine kinase (CK), muscle soreness, femoral artery blood flow, plasma IL-6 and sleep were also assessed pre and post-treatment. There were significant decreases in muscle torque for WBC4 (10.9%, p = 0.04) and CON (11.3% p = 0.00) and no significant decreases for WBC1 (5.6%, p = 0.06) and CWI (5.1%, p = 0.15). There were no significant differences between groups in muscle soreness, CK, IL-6 or sleep. Femoral artery blood flow significantly decreased in CWI (p = 0.02), but did not differ in other groups. WBC treatments within an hour may be preferable for muscle strength recovery compared to delayed treatments; however WBC appears to be no more effective than CWI. Neither cold intervention had an impact on inflammation or sleep.

A Pro-Inflammatory Signature Constitutively Activated in Monogenic Autoinflammatory Diseases

Autoinflammatory diseases (AIDs) are disorders characterised by recurrent inflammatory episodes in charge of different organs with no apparent involvement of autoantibodies or antigen-specific T lymphocytes. Few common clinical features have been identified among all monogenic AIDs (mAIDs), while the search for a common molecular pattern is still ongoing. The aim of this study was to increase knowledge on the inflammatory pathways in the development of mAIDs in order to identify possible predictive or diagnostic biomarkers for each disease and to develop future preventive and therapeutic strategies. Using protein array-based systems, we evaluated two signalling pathways known to be involved in inflammation and a wide range of inflammatory mediators (pro-inflammatory cytokines and chemokines) in a cohort of 23 patients affected by different mAIDs, as FMF, TRAPS, MKD, Blau syndrome (BS), and NLRP12D. Overall, we observed upregulation of multiple signalling pathway intermediates at protein levels in mAIDs patients’ PBMCs, compared with healthy controls, with significant differences also between patients. FMF, TRAPS, and BS presented also peculiar activations of inflammatory pathways that can distinguish them. MAPK pathway activation, however, seems to be a common feature. The serum level of cytokines and chemokines produced clear differences between patients with distinct diseases, which can help distinguish each autoinflammatory disease. The FMF cytokine production profile appears broader than that of TRAPS, which, in turn, has higher cytokine levels than BS. Our findings suggest an ongoing subclinical inflammation related to the abnormal and constitutive signalling pathways and define an elevated inflammatory cytokine signature. Moreover, the upregulation of Th17-related cytokines emphasises the important role for Th17 and/or Th17-like cells also in monogenic AIDs.

Complement multiplex testing: Concept, promises and pitfalls

Complement is a complex system. This complexity becomes more obvious when looking at complement analysis in health and disease, where one presentation can require a number of measurements to understand the full role of this cascade in the disease. The current state of clinical testing requires multiple tests to cover the whole of the complement cascade. There is a clear potential for multiplex testing to help address this need for comprehensive analysis of the state of complement deficiency, activation or inhibition. Fortunately, there are a number of potential methods for multiplex analysis, each with advantages and disadvantages that need to be considered in light of the intricacy of the complement cascade and its interconnection to other systems. Despite the complexities of such methods several groups have started utilizing multiplex analysis for research and even for diagnostic testing. The potential methods, current successes, and the type of testing that needs to be streamlined are reviewed in this text.

Alzheimer's disease: a step closer to understanding type 3 diabetes in African Americans

Alzheimer's disease (AD) is the fourth leading cause of death in the United States and the most common cause of adult-onset dementia. Recent results suggest an increased prevalence and severity in African Americans compared to Caucasians. Our understanding of the potential mechanism(s) underlying this ethnicity difference is limited. We previously described ethnicity-related differences in levels of neurodegenerative proteins and cytokines/chemokines in the BA21 region of African Americans and Caucasians with AD. Here, similar multiplex assays were used to examine those endpoints in patient postmortem cerebrospinal fluid (CSF). Additionally, we measured levels of C-peptide, ghrelin, gastric inhibitory polypeptide (GIP), glucagon-like peptide-1 (GLP-1), glucagon, insulin, leptin, PAI-1, resistin, and visfatin using a human diabetes 10-plex assay. The cytokine and chemokine assays revealed that levels of 26 chemokines or cytokines differed significantly with ethnicity, and three of those were significantly associated with gender. The neurodegenerative disease panel indicated that levels of soluble RAGE were significantly elevated in African Americans compared to Caucasians. All measures in the diabetes disease panel assay were significantly elevated in African Americans: ghrelin, GIP, GLP-1, glucagon, insulin, and visfatin. Through peripheral sample analysis, these results provide further evidence that ethnicity is critically involved in the manifestation of AD.

Clinical significance of measuring serum cytokine levels as inflammatory biomarkers in adult and pediatric COVID-19 cases: A review

Coronavirus disease 2019 (COVID-19) is a rapidly evolving infectious/inflammatory disorder which has turned into a global pandemic. With severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as its etiologic agent, severe COVID-19 cases usually develop uncontrolled inflammatory responses and cytokine storm-like syndromes. Measuring serum levels of pro-inflammatory cytokines (e.g., IL-6 and others) as inflammatory biomarkers may have several potential applications in the management of COVID-19, including risk assessment, monitoring of disease progression, determination of prognosis, selection of therapy and prediction of response to treatment. This is especially true for pediatric patients with COVID-19 associated Kawasaki-like disease and similar syndromes. In this report, we review the current knowledge of COVID-19 associated cytokines, their roles in host immune and inflammatory responses, the clinical significance and utility of cytokine immunoassays in adult and pediatric COVID-19 patients, as well as the challenges and pitfalls in implementation and interpretation of cytokine immunoassays. Given that cytokines are implicated in different immunological disorders and diseases, it is challenging to interpret the multiplex cytokine data for COVID-19 patients. Also, it should be taken into consideration that biological and technical variables may affect the commutability of cytokine immunoassays and enhance complexity of cytokine immunoassay interpretation. It is recommended that the same method, platform and laboratory should be used when monitoring differences in cytokine levels between groups of individuals or for the same individual over time. It may be important to correlate cytokine profiling data with the SARS-CoV-2 nucleic acid amplification testing and imaging observations to make an accurate interpretation of the inflammatory status and disease progression in COVID-19 patients.

Aging and chronic high-fat feeding negatively affect kidney size, function, and gene expression in CTRP1-deficient mice

C1q/TNF-related protein 1 (CTRP1) is an endocrine factor with metabolic, cardiovascular, and renal functions. We previously showed that aged Ctrp1-knockout (KO) mice fed a control low-fat diet develop renal hypertrophy and dysfunction. Since aging and obesity adversely affect various organ systems, we hypothesized that aging, in combination with obesity induced by chronic high-fat feeding, would further exacerbate renal dysfunction in CTRP1-deficient animals. To test this, we fed wild-type and Ctrp1-KO mice a high-fat diet for 8 mo or longer. Contrary to our expectation, no differences were observed in blood pressure, heart function, or vascular stiffness between genotypes. Loss of CTRP1, however, resulted in an approximately twofold renal enlargement (relative to body weight), ∼60% increase in urinary total protein content, and elevated pH, and changes in renal gene expression affecting metabolism, signaling, transcription, cell adhesion, solute and metabolite transport, and inflammation. Assessment of glomerular integrity, the extent of podocyte foot process effacement, as well as renal response to water restriction and salt loading did not reveal significant differences between genotypes. Interestingly, blood platelet, white blood cell, neutrophil, lymphocyte, and eosinophil counts were significantly elevated, whereas mean corpuscular volume and hemoglobin were reduced in Ctrp1-KO mice. Cytokine profiling revealed increased circulating levels of CCL17 and TIMP-1 in KO mice. Compared with our previous study, current data suggest that chronic high-fat feeding affects renal phenotypes differently than similarly aged mice fed a control low-fat diet, highlighting a diet-dependent contribution of CTRP1 deficiency to age-related changes in renal structure and function.

In vitro antitumor, pro-inflammatory, and pro-coagulant activities of Megalopyge opercularis J.E. Smith hemolymph and spine venom

Contact with stinging spines venom from several Lepidoptera larvae may result in skin lesions. In Mexico, envenomation outbreaks caused by Megalopyge opercularis were reported between 2015 and 2016. The aim of this study was to identify the venomous caterpillars in Nuevo Leon, Mexico and evaluate several biological activities of their hemolymph (HEV) and spine setae (SSV) venoms. M. opercularis was identified by cytochrome oxidase subunit (COI) designed primers. HEV and SSV extracts cytotoxic activity was assessed on the L5178Y-R lymphoma cell line. For apoptotic cells number and apoptosis, cells were stained with acridine orange/ethidium bromide and validated by DNA fragmentation. Human peripheral blood mononuclear cells (hPBMC) cytokine response to the extracts was measured by the cytometric bead array assay. Extracts effect on pro-coagulation activity on human plasma was also evaluated. HEV and SSV extracts significantly inhibited (p < 0.01) up to 63% L5178Y-R tumor cell growth at 125–500 µg/mL, as compared with 43% of Vincristine. About 79% extracts-treated tumor cells death was caused by apoptosis. Extracts stimulated (p < 0.01) up to 60% proliferation of resident murine lymphocytes, upregulated IL-1β, IL-6, IL-8, and TNF-α production by hPBMC, and showed potent pro-coagulant effects. The pharmacological relevance of these venoms is discussed.

Recent advances and new strategies in Leishmaniasis diagnosis

Leishmaniasis is a set of complex and multifaceted syndromes, with different clinical manifestations, caused by different species of the genus Leishmania spp. that can be characterized by at least four syndromes: visceral leishmaniasis (VL, also known as kala-azar), post-kala-azar dermal leishmaniasis (PKDL), cutaneous leishmaniasis (CL), and mucocutaneous leishmaniasis (MCL). Among the most serious clinical forms, VL stands out, which causes the death of around 59,000 people annually. Fast and accurate diagnosis in VL is essential to reduce the disease's morbidity and mortality. There are a large number of diagnostic tests for leishmaniasis, however they do cross-react with other protozoa and their sensitivity changes according to the clinical form of the disease. Thus, it is essential and necessary to provide a diagnosis that is sufficiently sensitive to detect asymptomatic infected individuals and specific to discriminate individuals with other infectious and parasitic diseases, thus enabling more accurate diagnostic tools than those currently used. In this context, the aim of this review is to summarize the conventional diagnostic tools and point out the new advances and strategies on visceral and cutaneous leishmaniasis diagnosis.

Validation of a commercial magnetic bead-based multiplex assay for 5 novel biomarkers of acute kidney injury in canine serum

Interest is growing in measurement of novel biomarkers for the diagnosis of acute kidney injury. Multiplex assays may provide a rapid and cost-effective way of measurement; however, sparse information is published regarding their use in dogs. We aimed to validate a commercial magnetic bead-based assay for 5 biomarkers: clusterin (Clus), cystatin C (CysC), kidney injury molecule 1 (KIM-1), monocyte chemoattractant protein 1 (MCP-1), and neutrophil gelatinase-associated lipocalin (NGAL). Intra- and inter-assay imprecision, linearity under dilution (LUD), spike recovery (S-R), and hemoglobin interference were evaluated using serum from healthy and diseased dogs. Additionally, the effect of sample type (serum vs. plasma) was investigated. All values for Clus and MCP-1 were outside the assay's measurable range. Intra- and inter-assay precision were acceptable for NGAL (CVs 8.8% and 13.2%, respectively). Regression analysis of LUD and S-R indicated good linearity for CysC and NGAL. Hemolysis did not affect measurement of any biomarker. Measured concentrations of CysC (p = 0.018) and NGAL (p = 0.015) were significantly lower in sodium citrate plasma compared to serum. We conclude that this magnetic bead-based assay is precise and accurate for NGAL measurement in canine serum. Inappropriate standards for MCP-1 and Clus, and poor accuracy for KIM-1 measurement, suggest that this assay cannot reliably quantify those biomarkers in canine blood. Measurements of CysC in canine blood using this assay must be interpreted with caution given inter-assay imprecision.

Pro-inflammatory cytokine ratios determine the clinical course of febrile neutropenia in children receiving chemotherapy

Background

Febrile neutropenia is a common and serious complication during treatment of childhood cancer. Empirical broad-spectrum antibiotics are usually administered until neutrophil cell count recovery. It was the aim of this study to investigate cytokine profiles as potential biomarkers using in-vitro sepsis models to differentiate between distinct clinical courses of febrile neutropenia (FN).

Methods

We conducted an observational study in FN episodes of pediatric oncology patients. Courses of neutropenia were defined as severe in case of proven blood stream infection or clinical evidence of complicated infection. We collected blood samples at various time points from the onset of FN and stimulated ex vivo with lipopolysaccharide (LPS) and Staphylococcus epidermidis (SE) for 24 h. Twenty-seven cytokine levels were measured in the whole blood culture supernatants by a multiplex immunoassay system.

Results

Forty-seven FN episodes from 33 children were investigated. IL-8, IL-1β, and MCP-1 expression increased significantly over time. IL-8, MIP-1α, MIP-1β, MCP-1, and TNF-α showed significantly lower concentration in patients with a clinically severe course of the FN.

Conclusions

Distinct patterns of cytokine profiles seem to be able to determine infectious FN and to predict the severity of its clinical course. If these data can be verified in a multi-centre setting, this may finally lead to an individualized treatment strategy facilitating antibiotic stewardship in these patients.

A double-hit of stress and low-grade inflammation on functional brain network mediates posttraumatic stress symptoms

Growing evidence indicates a reciprocal relationship between low-grade systemic inflammation and stress exposure towards increased vulnerability to neuropsychiatric disorders, including posttraumatic stress disorder (PTSD). However, the neural correlates of this reciprocity and their influence on the subsequent development of PTSD are largely unknown. Here we investigated alterations in functional connectivity among brain networks related to low-grade inflammation and stress exposure using two large independent data sets. Functional couplings among the higher-order cognitive network system including the salience, default mode, and central executive networks were reduced in association with low-grade inflammation and stress exposure. This reduced functional coupling may also be related to subsequent posttraumatic stress symptom severity. The current findings propose functional couplings among the higher-order cognitive network system as neural correlates of low-grade inflammation and stress exposure, and suggest that low-grade inflammation, alongside with stress, may render individuals more vulnerable to PTSD.

Late-onset renal hypertrophy and dysfunction in mice lacking CTRP1

Local and systemic factors that influence renal structure and function in aging are not well understood. The secretory protein C1q/TNF-related protein 1 (CTRP1) regulates systemic metabolism and cardiovascular function. We provide evidence here that CTRP1 also modulates renal physiology in an age- and sex-dependent manner. In mice lacking CTRP1, we observed significantly increased kidney weight and glomerular hypertrophy in aged male but not female or young mice. Although glomerular filtration rate, plasma renin and aldosterone levels, and renal response to water restriction did not differ between genotypes, CTRP1-deficient male mice had elevated blood pressure. Echocardiogram and pulse wave velocity measurements indicated normal heart function and vascular stiffness in CTRP1-deficient animals, and increased blood pressure was not due to greater salt retention. Paradoxically, CTRP1-deficient mice had elevated urinary sodium and potassium excretion, partially resulting from reduced expression of genes involved in renal sodium and potassium reabsorption. Despite renal hypertrophy, markers of inflammation, fibrosis, and oxidative stress were reduced in CTRP1-deficient mice. RNA sequencing revealed alterations and enrichments of genes in metabolic processes in CTRP1-deficient animals. These results highlight novel contributions of CTRP1 to aging-associated changes in renal physiology.

Potential chemokine biomarkers associated with PTSD onset, risk and resilience as well as stress responses in US military service members

Cytokines, including chemokines, are small secreted proteins, which specifically effect on the interactions and communications between cells. Pro-inflammatory cytokines are produced predominantly by activated macrophages and are involved in the upregulation of inflammatory reactions. Dysregulation of cytokines is associated with post-traumatic stress disorder (PTSD). Here, we use both before-and-after and case-control studies to search for potential chemokine biomarkers associated with PTSD onset, risk, and resilience as well as stress responses in US military service members deployed to Iraq and Afghanistan. Blood samples and scores of the PTSD Checklist (PCL) were obtained from soldiers pre- and post deployment (pre, post). Forty chemokines were measured using the Bio-Plex Pro Human Chemokine Panel Assays. The before-and-after analysis showed potential markers (CCL2, CCL15, CCL22, CCL25, CXCL2, and CXCL12) are associated with PTSD onset, and CCL3, CXCL11, and CXCL16 are related to stress response. The case-control study demonstrated that CCL13, CCL20, and CXCL6 were possible PTSD risk markers, and CX3CL1 might be a resilience marker. In addition, CCL11, CCL13, CCL20, and CCL25 were correlated with the PCL scores, indicating their association with PTSD symptom severity. Our data, for the first time, suggest that these dysregulated chemokines may serve as biomarkers for PTSD onset, risk, and resilience as well as stress responses, and may benefit developing approaches not only for PTSD diagnosis but also for PTSD treatment.

Increased inflammation in BA21 brain tissue from African Americans with Alzheimer's disease

Chronic neuroinflammation is strongly associated with AD and altered peripheral and central levels of chemokines and cytokines have been frequently described in those with AD. Given the increasing evidence of ethnicity-related differences in AD, it was of interest to determine if those altered chemokine and cytokine levels are ethnicity-related. Because African Americans exhibit a higher incidence of AD and increased symptom severity, we explored chemokine and cytokine concentrations in post-mortem brain tissue from the BA21 region of African Americans and Caucasians with AD using multiplex assays. IL-1β, MIG, TRAIL, and FADD levels were significantly increased in African Americans while levels of IL-3 and IL-8 were significantly decreased. Those effects did not interact with gender; however, overall levels of CCL25, CCL26 and CX3CL1 were significantly decreased in women. The NLRP3 inflammasome is thought to be critically involved in AD. Increased activation of this inflammasome in African Americans is consistent with the current results.

Cigarette smoking differentially affects immunoglobulin class levels in serum and saliva: An investigation and review

The aim of the present study was to compare concentrations of IgG, IgA, IgM and IgD in both serum and saliva samples from smoking and non-smoking individuals using a protein microarray assay. The findings were also compared to previous studies. Serum and saliva were collected from 48 smoking male individuals and 48 age-matched never-smoker male individuals. The protein microarray assays for detection of human IgG, IgM, IgA and IgD were established and optimized using Ig class-specific affinity-purified goat anti-human Ig-Fc capture antibodies and horseradish peroxidase (HRP)-conjugated goat anti-human Ig-Fc detection antibodies. The Ig class specificity of the microarray assays was verified, and the optimal dilutions of serum and saliva samples were determined for quantification of Ig levels against standard curves. We found that smoking is associated with reduced IgG concentrations and enhanced IgA concentrations in both serum and saliva. By contrast, smoking differentially affected IgM concentrations-causing increased concentrations in serum, but decreased concentrations in saliva. Smoking was associated with decreased IgD concentrations in serum and did not have a significant effect on the very low IgD concentrations in saliva. Thus, cigarette smoking differentially affects the levels of Ig classes systemically and in the oral mucosa. Although there is variation between the results of different published studies, there is a consensus that smokers have significantly reduced levels of IgG in both serum and saliva. A functional antibody deficiency associated with smoking may compromise the body's response to infection and result in a predisposition to the development of autoimmunity.

Thermal stability of cytokines: A review

BACKGROUND

The role of cytokines in various disease states is a burgeoning field of academic study and clinical application, however there are no consensus documents on how certain cytokines should be stored prior to quantification. This information is especially of interest to researchers assembling a biobank or clinicians who have to transport specimens to a different location in order to be tested.

OBJECTIVE

To review the literature and synthesize prior findings on cytokine storage and freeze/thaw stability.

DESIGN

We searched PubMed for articles related to cytokine storage stability. All articles were analyzed for cytokines studied, source of reported cytokine concentration (i.e., human whole blood or serum, concentrations from other species or bodily sources were excluded), and reported statistical results.

RESULTS

We identified and synthesized results of 23 peer-reviewed articles which published data on the storage and freeze/thaw stability of 33 different cytokines and chemokines.

CONCLUSION

There is a wide variety of reported cytokine storage and freeze/thaw stability. Interleukin-6 and tumor necrosis factor alpha are the most widely studied cytokines in regard to temperature stability. In a few cytokines, a clear consensus can be reached as to storage safety at particular temperatures, but in most, more research needs to be done and we advise the clinician or researcher to use caution in interpreting cytokine concentration results after a long period of storage or several freeze/thaw cycles.

Determining Whether Hypertensive Status and Stress Level Are Associated With Inflammatory Markers

BACKGROUND

Hypertensive disorders are common pregnancy complications in the United States. Although the exact mechanism underlying hypertensive disorders in pregnancy is unknown, there is evidence of involvement of a maladaptive maternal inflammatory response. Psychological maternal stress experienced during pregnancy can increase the risk of a hypertensive disorder by altering the maternal inflammatory response.

OBJECTIVES

The purpose of this analysis was to evaluate the relationships of hypertensive status and stress with inflammatory biomarkers throughout pregnancy.

METHOD

A 1:2 case-control design was used to analyze secondary data longitudinally with repeated measures of a multicenter, culturally and ethnically diverse pregnant population. Demographic data, psychological stress, and serum inflammatory data were analyzed. The sample consisted of 30 pregnant women with hypertension and 61 normotensive women. Measurements were taken once in each trimester of pregnancy.

RESULTS

Trimester-specific levels of inflammatory biomarkers varied based on stress and hypertensive status. IL-6 was elevated in the hypertensive, high-stress group, while IL-8 was greater among those with high stress, regardless of hypertensive status or trimester. For IL-1α and IL-1β, there was a significant stress-by-trimester interaction, while IL-10 was associated with a significant three-way interaction among stress level, hypertension status, and trimester.

CONCLUSIONS

The associations of stress and hypertensive status with inflammatory biomarkers are complex. Stress and hypertension were associated with changes in inflammatory response. Hypertensive women with high stress experienced a heightened anti-inflammatory response, potentially a compensatory mechanism. To better understand this relationship, further longitudinal studies are warranted.

Cancer protein biomarker discovery based on nucleic acid aptamers

Identification of biomarkers is essential for diagnosis, targeted therapy and prognosis evaluation of diseases, especially cancers. Currently, the number of ideal clinical biomarkers is still limited partially because of lacking efficient methods in biomarker discovery. Nucleic acid aptamers are artificial single-stranded DNA or RNA sequences that can selectively bind to various targets with high specificity and affinity. Moreover, aptamers possess desirable advantages, including easy synthesis, convenient modification, relative chemical stability and low immunogenicity. Recently, different aptamer-based strategies have been developed to facilitate the discovery of biomarkers. Based on cell-SELEX technology, the selected aptamers can be used to identify cell-surface protein biomarkers of different cancer cells. SOMAscan can analyze thousands of proteins of different biological samples, which becomes a multiplexed protein biomarker discovery platform. Additionally, secreted protein biomarkers can be discovered by aptamers screened through secretome SELEX. In order to facilitate the identification of target proteins, several covalent cross-linking strategies have been developed, such as aptamer-based affinity labeling (ABAL), DNA-templated aptamer and protein-aptamer template (PAT). In this review, we mainly highlight the emerging nucleic acid aptamer-based biomarker discovery strategies and demonstrate their unique technological advantages in discovering cancer biomarkers. The challenges and perspectives of aptamer-based methods are also discussed.

Proteomic profiles by multiplex microsphere suspension array

Advances in high-throughput proteomic approaches have provided substantial momentum to novel disease-biomarker discovery research and have augmented the quality of clinical studies. Applications based on multiplexed microsphere suspension array technology are making strong in-roads into the clinical diagnostic/prognostic practice. Conventional proteomic approaches are designed to discover a broad set of proteins that are associated with a specific medical condition. In comparison, multiplex microsphere immunoassays use quantitative measurements of selected set(s) of specific/particular molecular markers such as cytokines, chemokines, pathway signaling or disease-specific markers for detection, metabolic disorders, cancer, and infectious agents causing human, plant and animal diseases. This article provides a foundation to the multiplexed microsphere suspension array technology, with an emphasis on the improvements in the technology, data analysis approaches, and applications to translational and clinical research with implications for personalized and precision medicine.

Nanoparticle Enhancement Cascade for Sensitive Multiplex Measurements of Biomarkers in Complex Fluids with Surface Plasmon Resonance Imaging

There is a large unmet need for reliable biomarker measurement systems for clinical application. Such systems should meet challenging requirements for large scale use, including a large dynamic detection range, multiplexing capacity, and both high specificity and sensitivity. More importantly, these requirements need to apply to complex biological samples, which require extensive quality control. In this paper, we present the development of an enhancement detection cascade for surface plasmon resonance imaging (SPRi). The cascade applies an antibody sandwich assay, followed by neutravidin and a gold nanoparticle enhancement for quantitative biomarker measurements in small volumes of complex fluids. We present a feasibility study both in simple buffers and in spiked equine synovial fluid with four cytokines, IL-1β, IL-6, IFN-γ, and TNF-α. Our enhancement cascade leads to an antibody dependent improvement in sensitivity up to 40 000 times, resulting in a limit of detection as low as 50 fg/mL and a dynamic detection range of more than 7 logs. Additionally, measurements at these low concentrations are highly reliable with intra- and interassay CVs between 2% and 20%. We subsequently showed this assay is suitable for multiplex measurements with good specificity and limited cross-reactivity. Moreover, we demonstrated robust detection of IL-6 and IL-1β in spiked undiluted equine synovial fluid with small variation compared to buffer controls. In addition, the availability of real time measurements provides extensive quality control opportunities, essential for clinical applications. Therefore, we consider this method is suitable for broad application in SPRi for multiplex biomarker detection in both research and clinical settings.

Multiplex Quantification Identifies Novel Exercise-regulated Myokines/Cytokines in Plasma and in Glycolytic and Oxidative Skeletal Muscle

Exercise is known to confer major health benefits, but the underlying mechanisms are not well understood. The systemic effects of exercise on multi-organ systems are thought to be partly because of myokines/cytokines secreted by skeletal muscle. The extent to which exercise alters cytokine expression and secretion in different muscle fiber types has not been systematically examined. Here, we assessed changes in 66 mouse cytokines in serum, and in glycolytic (plantaris) and oxidative (soleus) muscles, in response to sprint, endurance, or chronic wheel running. Both acute and short-term exercise significantly altered a large fraction of cytokines in both serum and muscle, twenty-three of which are considered novel exercise-regulated myokines. Most of the secreted cytokine receptors profiled were also altered by physical activity, suggesting an exercise-regulated mechanism that modulates the generation of soluble receptors found in circulation. A greater overlap in cytokine profile was seen between endurance and chronic wheel running. Between fiber types, both acute and chronic exercise induced significantly more cytokine changes in oxidative compared with glycolytic muscle. Further, changes in a subset of circulating cytokines were not matched by their changes in muscle, but instead reflected altered expression in liver and adipose tissues. Last, exercise-induced changes in cytokine mRNA and protein were only minimally correlated in soleus and plantaris. In sum, our results indicate that exercise regulates many cytokines whose pleiotropic actions may be linked to positive health outcomes. These data provide a framework to further understand potential crosstalk between skeletal muscle and other organ compartments.

Of Cytometry, Stem Cells and Fountain of Youth

Outlined are advances of cytometry applications to identify and sort stem cells, of laser scanning cytometry and ImageStream imaging instrumentation to further analyze morphometry of these cells, and of mass cytometry to classify a multitude of cellular markers in large cell populations. Reviewed are different types of stem cells, including potential candidates for cancer stem cells, with respect to their "stemness", and other characteristics. Appraised is further progress in identification and isolation of the "very small embryonic-like stem cells" (VSELs) and their autogenous transplantation for tissue repair and geroprotection. Also assessed is a function of hyaluronic acid, the major stem cells niche component, as a guardian and controller of stem cells. Briefly appraised are recent advances and challenges in the application of stem cells in regenerative medicine and oncology and their future role in different disciplines of medicine, including geriatrics.

A Novel Observational Method for Assessing Acute Responses to Cannabis: Preliminary Validation Using Legal Market Strains

Background: The development of novel cannabis research methods that are compatible with current federal regulations is imperative to conduct studies of the effects of legal market cannabis. There is very little research on higher strength, higher Δ9-tetrahydrocannabinol (THC), which has become increasingly available since legalization. Research on strains containing cannabidiol (CBD), a second primary, but nonpsychotomimetic, cannabinoid, is very limited. Materials and Methods: Using a novel observational methodology, regular cannabis users were asked to use one of two legal market cannabis strains that they purchased from a local dispensary (one strain containing 8% THC and 16% CBD (THC+CBD) and one containing a 17% THC concentration, but no CBD (THC). After using their suggested cannabis strain as they typically would for a 3-day period, participants returned to the laboratory immediately after their final use. Measures included a blood draw to measure cannabinoid blood levels and circulating cytokines, self-reported subjective drug effects, and verbal recall memory. Results: Analysis of CBD/THC concentration levels in the blood following the 3-day strain manipulation suggests that all, but one participant (n=23/24) followed instructions and used their assigned strain. Individuals in the THC group (n=11) smoked no more than their usual amount, and participants who used the THC+CBD (n=12) strain smoked more than their reported usual amount, but did not have significantly different THC+metabolite blood levels from the THC group. The THC+CBD strain was also associated with less desire to smoke, lower levels of subjective drug effects, and lower levels of circulating cytokines (TNF-α, IL-6, and IL-1β) immediately after use. Conclusions: Initial results support the feasibility of this novel observational methodology involving brief manipulation of strain use. Preliminary findings indicate that participants may self-titrate cannabis use based on cannabinoid concentration and the THC+CBD strain was associated with lower levels of cannabis craving, subjective intoxication, and circulating cytokines.

Circulating cytokine levels are associated with symptoms of depression and anxiety among people with alcohol and drug use disorders

BACKGROUND

Psychological distress is common among people with a substance abuse disorder in treatment. Identifying correlates of psychological distress may serve as points of intervention to improve substance abuse treatment outcomes. Immune function measured as cytokine levels have been associated with psychological distress, but this association remains unexplored among people with a substance abuse disorder in treatment. This study aimed to examine whether cytokine levels in patients treated for a substance use disorder were related to depression, anxiety, and overall psychological distress, and to observe these associations separately among people with a past year alcohol use disorder and those with a past year drug use disorder.

METHODS

We collected cross-sectional data from 80 inpatients at five alcohol and substance abuse treatment centers in Norway. We determined alcohol and drug diagnoses, and assessed symptoms of depression, anxiety, and overall psychological distress. We tested blood samples for IL-1, IL-6, TNF-α, INF-γ, and IL-10. We used multivariate linear regressions to examine the associations between cytokine levels and psychological distress measures.

RESULTS

All cytokines were significantly and positively associated with depression score. INF-γ was significantly and negatively associated with anxiety, and IL-6 was significantly and positively associated psychological distress. Among people with only an alcohol use disorder, IL-6 was positively associated with depression and psychological distress scores, and IL-10 was negatively associated with anxiety score. Among people with only a drug use disorder, TNF-α was positively associated with depression score.

CONCLUSION

The relationship between immune function and psychological distress is robust in the context of substance abuse, and further research is warranted.

Analytical performance of a commercial multiplex Luminex-based cytokine panel in the rat

INTRODUCTION

Multiplex immunoassays are an important tool in biomarker research during preclinical drug development. However, information regarding analytical performance of commercial multiplex assays for animal species is often limited. To be able to correctly interpret study results, a fit-for-purpose validation approach is recommended. The objective of our study was to provide a realistic example of what level of validation can be expected from this type of assay, using a rat cytokine panel.

METHODS

The analytical performance of a commercial Luminex-based multiplex assay comprising IFN-γ, IL-6, IL-10, IL-12p70, IP-10 and TNF-α was evaluated in Sprague-Dawley rat plasma and serum. Calibration curve, working range, precision, accuracy, selectivity, parallelism, dilutional linearity, prozone effect and sample stability were assessed.

RESULTS

Analytical performance in plasma and serum was comparable. Precision and accuracy results for all analytes were acceptable with coefficient of variation (CV) and relative error (RE) often below 15%, except for serum IL-6. Selectivity results varied per analyte with several cytokines showing CV>30% and no single minimum required dilution (MRD) could be identified. In addition, some striking differences between recombinant and endogenous protein results were observed. A pronounced prozone effect was detected for IP-10. Analytes in samples stored at -70°C were stable (RE<30%) from 1 up to 6months depending on the analyte.

DISCUSSION

The results illustrate the challenges encountered during validation of commercial animal Luminex-based multiplex assays, revealing analytical limitations such as matrix and prozone effects. The Milliplex rat cytokine panel under investigation was deemed suitable for relative quantification of exploratory type biomarkers.

Bead Based Multiplex Assay for Analysis of Tear Cytokine Profiles

Tear film is a complex mixture of lipids, proteins and minerals which covers the external surface of the eye, thereby providing lubrication, nutrition and protection to the underlying cells. Analysis of tears is an emerging area for the identification of biomarkers for the prediction, diagnosis, and prognosis of various ocular diseases. Tears are easily accessible and their collection is non-invasive. Therefore, advancing technologies are gaining prominence for identification of multiple analytes in tears to study changes in protein or metabolite composition and its association with pathological conditions. Tear cytokines are ideal biomarkers for studying the health of the ocular surface and also help in understanding the mechanisms of different ocular surface disorders like dry eye disease and vernal conjunctivitis. Bead based multiplex assays have the capability of detecting multiple analytes in a small amount of sample with a higher sensitivity. Here we describe a standardized protocol of tear sample collection, extraction and analysis of cytokine profiling using a bead based multiplex assay.

Multiplex Immunoassay Profiling of Serum in Psychiatric Disorders

Multiplex immunoassays allow for the rapid profiling of biomarker proteins in biological fluids, using less sample and labour than in single immunoassays. This chapter details the methods to develop and manufacture a 5-plex immunoassay for the Luminex® platform. Although assay development is not included here, the same methods can be used to covalently couple antibodies to the Luminex beads and to label antibodies for the screening of sandwich pairs, if needed. An example will be given for the analysis of five hormones (glucagon-like peptide 1, growth hormone, insulin, leptin and thyroid-stimulating hormone) in serum samples from schizophrenia patients and controls.

Ultrabright fluorescent silica particles with a large number of complex spectra excited with a single wavelength for multiplex applications

We report on a novel approach to synthesize ultrabright fluorescent silica particles capable of producing a large number of complex spectra. The spectra can be excited using a single wavelength which is paramount in quantitative fluorescence imaging, flow cytometry and sensing applications. The approach employs the physical encapsulation of organic fluorescent molecules inside a nanoporous silica matrix with no dye leakage. As was recently demonstrated, such an encapsulation allowed for the encapsulation of very high concentrations of organic dyes without quenching their fluorescent efficiency. As a result, dye molecules are distanced within ∼5 nm from each other; it theoretically allows for efficient exchange of excitation energy via Förster resonance energy transfer (FRET). Here we present the first experimental demonstration of the encapsulation of fluorescent dyes in the FRET sequence. Attaining a FRET sequence of up to five different dyes is presented. The number of distinguishable spectra can be further increased by using different relative concentrations of encapsulated dyes. Combining these approaches allows for creating a large number of ultrabright fluorescent particles with substantially different fluorescence spectra. We also demonstrate the utilization of these particles for potential multiplexing applications. Though fluorescence spectra of the obtained multiplex probes are typically overlapping, they can be distinguished by using standard linear decomposition algorithms.

Photobleaching kinetics-based bead encoding for multiplexed bioassays

Multiplexing bead-based bioassays requires that each type of microsphere be uniquely encoded to distinguish one type from another. Microspheres are typically encoded using fluorescent dyes with different spectral properties and varying concentrations. However practical limits exist on the number of dyes that can be spectrally resolved or the number of distinguishable intensity levels with each dye. To expand the number of encoding levels, a novel method was developed that incorporates photobleaching kinetics into bead decoding, unlocking additional multiplexing levels unattainable by conventional decoding methods. To demonstrate this technique, beads were encoded with two dyes having overlapping fluorescence excitation and emission wavelengths but different photostabilities. All beads initially exhibited similar fluorescence intensities; however, following appropriate photoexposure, the less photostable dye had reduced emission intensity due to photobleaching. By comparing the original fluorescence emission intensity to that obtained after photobleaching, multiple different populations could be reliably identified. Using only a single excitation/emission band, two different initial intensity levels were optimized to produce six uniquely identifiable bead populations whereas only two could have been achieved with conventional decoding methods. Incorporation of this encoding strategy into bead-based microwell array assays significantly increases the number of encoding levels available for multiplexed assays without increasing the complexity of the imaging instrumentation.

Influence of vaginal lactoferrin administration on amniotic fluid cytokines and its role against inflammatory complications of pregnancy

Background

An altered amniotic cytokine profile has been reported in inflammatory pregnancy complications with a leading role for IL-6, a marker of the foetal systemic inflammatory response. Up to this date there is no exhaustive information neither on the foetal cytokine balance nor on the best method for its modulation. We aimed to evaluate the influence of vaginal lactoferrin administration on amniotic fluid concentration of 47 cytokines, chemokines and growth factors.

Methods

Sixty women undergoing genetic amniocentesis were enrolled in an open-label clinical trial. 300 mg of vaginal lactoferrin (Florence, Italy) were randomly administered to obtain 3 groups: A, 20 untreated patients; B and C (20 patients in each) respectively treated 4 and 12 h before amniocentesis. Cytokines, chemokines and growth factors concentrations were quantified by a magnetic bead Luminex multiplex immunoassays panel technology. Data analysis was performed with the software Stata (v. 13.1) and GraphPad Prism (v. 5). Group comparisons were performed using Kruskal–Wallis followed by Mann–Whitney U tests, with Bonferroni correction for multiple comparisons. A p < 0.05 was considered significant.

Results

Among the 47 tested mediators, 24 (51.06%) were influenced by lactoferrin. 11 (23.4%), showed a highly significant difference (p <0.001); among these IL-9, IL-15, IFN-γ, IP-10, TNF-α, IL-1α and MCP-3 underwent a down-regulation, while IL-17 and FGF-basic, G-CSF, GM-CSF an up-regulation. Difference between group C and both B and A was small for IL-15, IP-10, IL-1α, MCP-3, while it was negligible for IL-9, IFN-γ and TNF-α. IL-17 and the 3 growth factors were strongly enhanced in B and C groups. IL-17, FGF-basic and GM-CSF showed increasing concentrations in both B and C groups, while G-CSF resulted up-regulated only in group C. Significance was intermediate (p < 0.01) for the down regulated IL-2RA, IL-12p40 and IFNα2 (6.38%) while it was small for 10 mediators (21.27%) 7 of which (IL-2, IL-4, eotaxin, PDGF-BB, RANTES, IL-18 and MIF) down-regulated and 3 (MCP-1, IL-3, and SDF-1α) up-regulated.

Conclusion

Lactoferrin down-regulates 17 pro-inflammatory amniotic mediators while up-regulating 7 anti-inflammatory amniotic mediators, 5 of which definitively belonging to an anti-inflammatory profile. These findings open to clinical investigation on its use against inflammatory complications of pregnancy.

High-Density Serum/Plasma Reverse Phase Protein Arrays

In-depth exploration and characterization of human serum and plasma proteomes is an attractive strategy for the identification of potential prognostic or diagnostic biomarkers. The possibility of analyzing larger numbers of samples in a high-throughput fashion has markedly increased with affinity-based microarrays, thus providing higher statistical power to these biomarker studies. Here, we describe a protocol for high-density serum and plasma reverse phase protein arrays (RPPAs). We demonstrate how a biobank of 12,392 samples was immobilized and analyzed on a single microarray slide, allowing high-quality profiling of abundant target proteins across all samples in one assay.

Multiplex Immunoassay Profiling

Multiplex immunoassays allow for the rapid profiling of biomarker proteins in biological fluids, using less sample and labor than single immunoassays. This chapter details the methods to develop and manufacture multiplex assays for the Luminex^® platform. Although assay development is not included here, the same methods can be used to covalently couple antibodies to the Luminex beads and to label antibodies for the screening of sandwich pairs, if needed. The assay optimization, detection of cross-reactivity, and minimizing antibody interactions and matrix interferences will be addressed.

Flow Cytometry as a Tool for Quality Control of Fluorescent Conjugates Used in Immunoassays

The use of antibodies in immunodiagnostic kits generally implies the conjugation of these proteins with other molecules such as chromophores or fluorochromes. The development of more sensitive quality control procedures than spectrophotometry is essential to assure the use of better fluorescent conjugates since the fluorescent conjugates are critical reagents for a variety of immunodiagnostic kits. In this article, we demonstrate a new flow cytometric protocol to evaluate conjugates by molecules of equivalent soluble fluorochromes (MESF) and by traditional flow cytometric analysis. We have coupled microspheres with anti-IgG-PE and anti-HBSAg-PE conjugates from distinct manufactures and/or different lots and evaluated by flow cytometry. Their fluorescence intensities were followed for a period of 18 months. Our results showed that there was a great difference in the fluorescence intensities between the conjugates studied. The differences were observed between manufactures and lots from both anti-IgG-PE and anti-HBSAg-PE conjugates. Coefficients of variation (CVs) showed that this parameter can be used to determine better coupling conditions, such as homogenous coupling. The MESF analysis, as well as geometric mean evaluation by traditional flow cytometry, showed a decrease in the values for all conjugates during the study and were indispensable tools to validate the results of stability tests. Our data demonstrated the feasibility of the flow cytometric method as a standard quality control of immunoassay kits.

Immunomodulatory roles of CTRP3 in endotoxemia and metabolic stress

C1q/TNF‐related protein 3 (CTRP3) is a secreted hormone that modulates hepatic glucose and lipid metabolism. Its circulating levels are reduced in human and rodent models of obesity, a metabolic state accompanied by chronic low‐grade inflammation. Recent studies have demonstrated an anti‐inflammatory role for recombinant CTRP3 in attenuating LPS‐induced systemic inflammation, and its deficiency markedly exacerbates inflammation in a mouse model of rheumatoid arthritis. We used genetic mouse models to explore the immunomodulatory function of CTRP3 in response to acute (LPS challenge) and chronic (high‐fat diet) inflammatory stimuli. In a sublethal dose of LPS challenge, neither CTRP3 deficiency nor its overexpression in transgenic mice had an impact on IL‐1β, IL‐6, TNF‐α, or MIP‐2 induction at the serum protein or mRNA levels, contrary to previous findings based on recombinant CTRP3 administration. In a metabolic context, we measured 71 serum cytokine levels in wild‐type and CTRP3 transgenic mice fed a high‐fat diet or a matched control low‐fat diet. On a low‐fat diet, CTRP3 transgenic mice had elevated circulating levels of multiple chemokines (CCL11, CXCL9, CXCL10, CCL17, CX3CL1, CCL22 and sCD30). However, when obesity was induced with a high‐fat diet, CTRP3 transgenic mice had lower circulating levels of IL‐5, TNF‐α, sVEGF2, and sVEGFR3, and a higher level of soluble gp130. Contingent upon the metabolic state, CTRP3 overexpression altered chemokine levels in lean mice, and attenuated systemic inflammation in the setting of obesity and insulin resistance. These results highlight a context‐dependent immunomodulatory role for CTRP3.

The potential use of biomarkers in predicting contrast-induced acute kidney injury

Contrast-induced acute kidney injury (CI-AKI) is a problem associated with the use of iodinated contrast media, causing kidney dysfunction in patients with preexisting renal failure. It accounts for 12% of all hospital-acquired kidney failure and increases the length of hospitalization, a situation that is worsening with increasing numbers of patients with comorbidities, including those requiring cardiovascular interventional procedures. So far, its diagnosis has relied upon the rise in creatinine levels, which is a late marker of kidney damage and is believed to be inadequate. Therefore, there is an urgent need for biomarkers that can detect CI-AKI sooner and more reliably. In recent years, many new biomarkers have been characterized for AKI, and these are discussed particularly with their use in known CI-AKI models and studies and include neutrophil gelatinase-associated lipocalin, cystatin C (Cys-C), kidney injury molecule-1, interleukin-18, N-acetyl-β-d-glucosaminidase, and L-type fatty acid-binding protein (L-FABP). The potential of miRNA and metabolomic technology is also mentioned. Early detection of CI-AKI may lead to early intervention and therefore improve patient outcome, and in future any one or a combination of several of these markers together with development in technology for their analysis may prove effective in this respect.

Increased levels of interleukin-33 in gingival crevicular fluids of patients with chronic periodontitis

The purpose of this clinical study is to comparatively investigate the interleukin-33 (IL-33) levels in gingival crevicular fluid (GCF), saliva and plasma of patients with periodontal disease as well as periodontally healthy subjects and the association between these levels and clinical parameters. GCF, saliva and plasma samples were collected from systemically healthy, non-smoker chronic periodontitis patients (CP group, n = 20), gingivitis patients (G group, n = 20) and periodontally healthy control groups (H group, n = 20). Full-mouth clinical periodontal parameters were also recorded. IL-33 levels were determined by ELISA. The total amount of GCF IL-33 was greater in the G and CP groups compared to the H group (p < 0.05). The GCF IL-33 concentration was significantly lower in the CP group than in the H and G groups (p < 0.001). Salivary or plasma IL-33 levels were similar in the study groups. The total amount of GCF IL-33 was positively correlated with the GI, PI and BOP (%) (p < 0.05). Considering the present findings, the increase in total amounts of GCF IL-33 may have a role in the pathogenesis of periodontal disease.

Tumor-Derived Exosomes and Their Role in Cancer Progression

Tumor cells actively produce, release, and utilize exosomes to promote tumor growth. Mechanisms through which tumor-derived exosomes subserve the tumor are under intense investigation. These exosomes are information carriers, conveying molecular and genetic messages from tumor cells to normal or other abnormal cells residing at close or distant sites. Tumor-derived exosomes are found in all body fluids. Upon contact with target cells, they alter phenotypic and functional attributes of recipients, reprogramming them into active contributors to angiogenesis, thrombosis, metastasis, and immunosuppression. Exosomes produced by tumors carry cargos that in part mimic contents of parent cells and are of potential interest as noninvasive biomarkers of cancer. Their role in inhibiting the host antitumor responses and in mediating drug resistance is important for cancer therapy. Tumor-derived exosomes may interfere with cancer immunotherapy, but they also could serve as adjuvants and antigenic components of antitumor vaccines. Their biological roles in cancer development or progression as well as cancer therapy suggest that tumor-derived exosomes are critical components of oncogenic transformation.

Divergent responses of inflammatory mediators within the amygdala and medial prefrontal cortex to acute psychological stress

There is now a growing body of literature that indicates that stress can initiate inflammatory processes, both in the periphery and brain; however, the spatiotemporal nature of this response is not well characterized. The aim of this study was to examine the effects of an acute psychological stress on changes in mRNA and protein levels of a wide range of inflammatory mediators across a broad temporal range, in key corticolimbic brain regions involved in the regulation of the stress response (amygdala, hippocampus, hypothalamus, medial prefrontal cortex). mRNA levels of inflammatory mediators were analyzed immediately following 30min or 120min of acute restraint stress and protein levels were examined 0h through 24h post-termination of 120min of acute restraint stress using both multiplex and ELISA methods. Our data demonstrate, for the first time, that exposure to acute psychological stress results in an increase in the protein level of several inflammatory mediators in the amygdala while concomitantly producing a decrease in the protein level of multiple inflammatory mediators within the medial prefrontal cortex. This pattern of changes seemed largely restricted to the amygdala and medial prefrontal cortex, with stress producing few changes in the mRNA or protein levels of inflammatory mediators within the hippocampus or hypothalamus. Consistent with previous research, stress resulted in a general elevation in multiple inflammatory mediators within the circulation. These data indicate that neuroinflammatory responses to stress do not appear to be generalized across brain structures and exhibit a high degree of spatiotemporal specificity. Given the impact of inflammatory signaling on neural excitability and emotional behavior, these data may provide a platform with which to explore the importance of inflammatory signaling within the prefrontocortical-amygdala circuit in the regulation of the neurobehavioral responses to stress.

Immunocapture strategies in translational proteomics

Aiming at clinical studies of human diseases, antibody-assisted assays have been applied to biomarker discovery and toward a streamlined translation from patient profiling to assays supporting personalized treatments. In recent years, integrated strategies to couple and combine antibodies with mass spectrometry-based proteomic efforts have emerged, allowing for novel possibilities in basic and clinical research. Described in this review are some of the field's current and emerging immunocapture approaches from an affinity proteomics perspective. Discussed are some of their advantages, pitfalls and opportunities for the next phase in clinical and translational proteomics.