Assessment of Pyrogenic Response of Medical Devices and Biomaterials by the Monocyte Activation Test (MAT): A Systematic Review.

Pyrogens are fever-inducing substances routinely investigated in health products through tests such as the Rabbit Pyrogen Test (RPT), the Limulus Amebocyte Lysate (LAL), and the Monocyte Activation Test (MAT). However, the applications of the MAT for medical devices and biomaterials remain limited. This work aimed to overview the studies evaluating the pyrogenicity of medical devices and biomaterials using the MAT, highlighting its successes and potential challenges. An electronic search was performed by December 2023 in PubMed, Scopus, and Web of Science, identifying 321 records which resulted in ten selected studies. Data were extracted detailing the tested materials, MAT variants, interferences, and comparisons between methods. Methodological quality was assessed using the ToxRTool, and the results were synthesized descriptively. The selected studies investigated various materials, including polymers, metals, and natural compounds, employing the different biological matrices of the MAT. Results showed the MAT's versatility, with successful detection of pyrogens in most materials tested, though variability in sensitivity was noted based on the material and testing conditions. Challenges remain in optimizing protocols for different material properties, such as determining the best methods for direct contact versus eluate testing and addressing the incubation conditions. In conclusion, the MAT demonstrates significant potential as a pyrogen detection method for medical devices and biomaterials. However, continued research is essential to address existing gaps, optimize protocols, and validate the test across a broader range of materials.

Uniform Suspension of Heat-Killed Staphylococcus aureus for a Positive Control Used in the Monocyte-Activation Test.

Pyrogens, classified as bacterial endotoxins and non-endotoxin pyrogens (NEPs), induce fever or shock when released into the bloodstream or spinal fluid. Recently, a monocyte-activation test (MAT) involving human cell culture has been developed to detect pyrogens in injectable products. To evaluate the sensitivity of MAT, a reference standard endotoxin was used as a positive control; however, the reactivity differed between the endotoxins and NEPs, necessitating positive controls for NEPs. This study aimed to explore a preparation method for heat-killed Staphylococcus aureus (HKSA) as a positive control for NEPs in MAT. Because S. aureus forms grape-like clusters, nine types of glass filters with pore sizes of 0.5-2.7 µm were evaluated to obtain a uniform bacterial suspension. The suspension was then heat-treated to kill the bacteria, resulting in HKSA samples. Serial dilutions of HKSA were tested by MAT using peripheral blood mononuclear cells. The interleukin-6 concentrations in the culture supernatant were measured by enzyme-linked immuno-sorbent assay to assess pyrogenic activities of HKSA. The pore sizes of the glass filters affected the uniformity of HKSA, and GF/C filter was selected for HKSA preparation. Repeated filtration improved uniformity, and a uniform suspension of HKSA was obtained through double filtration using a GF/C filter. Despite the decrease in HKSA activity as filtration frequency increased, the detection limit remained consistently unchanged. This suggests that repeated filtration can adjust the activity of HKSA to a baseline level and that a uniform suspension of HKSA exhibiting low variation is suitable as a positive control in MAT.

Proinflammatory Activation of Monocytes in Patients with Immunoinflammatory Rheumatic Diseases.

The pathogenesis of immunoinflammatory rheumatic diseases (IRDs) is based on chronic inflammation, one of the key mechanisms of which may be abnormal activation of macrophages, leading to further disruption of the immune system. OBJECTIVE: . The objective of this study was to evaluate the proinflammatory activation of circulating monocytes in patients with IRDs. MATERIALS AND METHODS: . The study involved 149 participants (53 patients with rheumatoid arthritis (RA), 45 patients with systemic lupus erythematosus (SLE), 34 patients with systemic scleroderma (SSc), and 17 participants without IRDs) 30 to 65 years old. Basal and lipopolysaccharide (LPS)-stimulated secretion of monocytes was studied in a primary culture of monocytes obtained from blood by immunomagnetic separation. Quantitative assessment of the cytokines tumor necrosis factor α (TNF-α), interleukin 1ß (IL-1ß), as well as the chemokine monocyte chemoattractant protein-1 (MCP-1) was carried out in the culture fluid by ELISA. Proinflammatory activation of monocytes was calculated as the ratio of LPS-stimulated and basal secretions. RESULTS: . It was shown that the basal secretion of all studied cytokines was significantly increased in all groups of patients with IRDs, except for the secretion of IL-1ß in the SLE group, compared to the control. LPS-stimulated secretion of TNF-α was increased and MCP-1 was decreased in patients with IRDs compared to the control group; LPS-stimulated IL-1ß secretion only in the SSc group significantly differed from the control group. In the RA group, monocyte activation was reduced for all cytokines compared to the control; in the SLE group, for TNF-α and MCP-1; in the SSc group, for MCP-1. CONCLUSIONS: . The decrease in proinflammatory activation of monocytes in patients with IRDs is due to a high level of basal secretion of cytokines, which can lead to disruption of the adequate immune response in these diseases and is an important link in the pathogenesis of chronic inflammation.

Hypertension and immune activation in antiretroviral therapy naïve people living with human immunodeficiency virus.

BACKGROUND: The pathogenesis of hypertension (HTN) in people living with HIV/AIDS (PLHIV) is complex and remains not fully understood. Chronic immune activation (IA) is postulated to be one of the culprits. This notion is derived from studies in HIV-uninfected populations and/or animals while data on HTN and how it relates to IA in PLHIV remains scarce. We determined the relationship between HTN and IA among antiretroviral therapy (ART) naïve PLHIV. METHODS: We analysed baseline data of 365 out of 430 clinical trial participants whose main aim was to investigate the effect of low-dose aspirin on HIV disease progression in PLHIV starting ART. Soluble CD14 (sCD14), T cells co-expressing CD38 and HLA-DR, and PD-1 were the IA and exhaustion markers, respectively studied and were analysed by flow cytometry. Mann-Whitney U-test was used for comparison of the markers by HTN status. A robust Poisson regression model was used to determine the predictors for HTN. RESULTS: A quarter of the 365 were hypertensive (25.3%, 95% CI 20.9-29.8%), and, had higher median (IQR) body mass index (kg/m2) (23.4 (19.6, 28.0) versus 21.9 (19.3, 25.1)) and lower median (IQR) estimated glomerular filtration rate (mL/min/1.73m2) (101.2 (79.4, 126.9) versus 113.6 (92.7, 138.8)) than normotensive participants (p < 0.05). Participants with HTN had higher median frequencies of all markers of IA and exhaustion but lower sCD14 (p > 0.05). None of these markers significantly predicted the occurrence of HTN. CONCLUSION: Studied markers of IA and exhaustion were higher in PLHIV with HTN than those without but were unpredictive of HTN. Larger multicentre studies with a wider range of markers are needed to confirm the role of IA in HIV-associated HTN.

Cytomegalovirus Immunoglobulin G Levels and Subclinical Arterial Disease among People Living with HIV in Botswana: A Cross-Sectional Study.

Cytomegalovirus (CMV) has been linked with increased cardiovascular risk and monocyte activation in people living with HIV (PLWH). This cross-sectional study aimed to compare CMV immunoglobulin G (IgG) levels between combined antiretroviral therapy (cART)-treated PLWH versus ART-naïve PLWH and those without HIV, and to investigate their associations with biomarkers of endothelial injury and carotid atherosclerosis, in Gaborone, Botswana. All participants were between 30 and 50 years old. Carotid intimal media thickness (cIMT) and biomarkers of endothelial injury and monocyte activation were also assessed. The association between quantitative CMV IgG and cardiovascular disease risk was assessed in multivariate logistic regression analysis. The results showed that the mean CMV IgG level among ART-naïve participants was significantly higher than both the cART group and controls. However, CMV IgG levels did not differ significantly between the controls and cART groups. Among PLWH, CMV IgG levels were associated with ICAM-1 levels and cIMT. Increases in CMV IgG among ART-naïve participants were significantly associated with increases in log VCAM-1. In conclusion, CMV IgG levels are elevated among PLWH in sub-Saharan Africa, and higher levels are associated with biomarkers of endothelial injury and cIMT. Future research should investigate the long-term impact of elevated CMV IgG among PLWH.

Using PBMCs in a Multiplex FluoroSpot Assay for Detection of Innate Immune Response-Modulating Impurities (IIRMIs).

The ELISA-based monocyte activation test (MAT) facilitates the replacement of the rabbit pyrogen test (RPT) for the detection of Innate Immune Response-Modulating Impurities (IIRMIs) in injectable drugs by activation of monocytes in human peripheral blood mononuclear cells (PBMCs). We describe the use of a triple-color IL-1ß/IL-6/TNF-α FluoroSpot assay as a sensitive tool for quantification of the frequencies of IIRMI-activated monocytes as well as determination of the relative amount of pyrogenic cytokine(s) produced by each activated cell.

IAPs and RIPK1 mediate LPS-induced cytokine production in healthy subjects and Crohn's disease.

Innate immune activity fuels intestinal inflammation in Crohn's disease (CD), an inflammatory bowel disease. Identification and targeting of new molecular regulators of the innate activity are warranted to control the disease. Inhibitor of apoptosis proteins (IAPs) regulate both cell survival and inflammatory signaling. We investigated the effects of IAP inhibition by second mitochondria-derived activator of caspases (SMAC) mimetics (SMs) on innate responses and cell death to pathogen-associated molecular patterns in peripheral blood mononuclear cells (PBMCs) and monocytes. IAPs inhibited lipopolysaccharide (LPS)-induced expression of proinflammatory interleukin (IL)-1ß, IL-6. Likewise, LPS (but not muramyl dipeptide or Escherichia coli) induced TNF-α was inhibited in CD and control PBMCs. The SM effect was partially reversed by inhibition of receptor-interacting serine/threonine-protein kinase 1 (RIPK1). The effect was mainly cell death independent. Thus, IAP inhibition by SMs leads to reduced production of proinflammatory cytokines and may be considered in the efforts to develop new therapeutic strategies to control CD.

Myocardial extracellular volume fraction is positively associated with activated monocyte subsets among cART-treated persons living with HIV in South Africa.

BACKGROUND: Despite treatment with combination antiretroviral therapy (cART), persons living with HIV (PLWH) are at higher risk of cardiac structural abnormalities that may presage clinical heart failure, including myocardial fibrosis. This study assessed whether circulating cellular and soluble protein markers of immune activation cross-sectionally associate with myocardial fibrosis among cART-treated PLWH in South Africa. METHODS: Participants were enrolled in Khayelitsha township near Cape Town, SA. Cardiac magnetic resonance imaging was performed. Plasma protein biomarkers were measured using enzyme-linked immunoassays and monocyte phenotypes were evaluated using flow cytometry. Associations were assessed using multivariable linear and logistic regression. RESULTS: Among 69 cART-treated PLWH, mean (SD) age was 48 (10) years, 71% were female, and time since HIV diagnosis was 9 (6) years. Evidence of left ventricular fibrosis by late gadolinium enhancement was present in 74% of participants and mean (SD) extracellular volume fraction (ECV) was 30.9 (5.9)%. Degree of myocardial fibrosis/inflammation measured by ECV was positively associated with percentages of circulating non-classical and intermediate monocyte phenotypes reflecting inflammation and tissue injury. CONCLUSION: These data generate hypotheses on possible immune mechanisms of HIV-associated non-ischemic myocardial disease, specifically among cART-treated PLWH in sub-Saharan Africa, where the majority of the HIV burden exists globally.

The future of pyrogenicity testing: Phasing out the rabbit pyrogen test. A meeting report.

The rabbit pyrogen test (RPT) was the benchmark for pyrogenicity testing, but scientific advancements have provided innovative and humane methods, such as the in vitro monocyte-activation test (MAT). However, transitioning from the RPT to the MAT has been challenging. The European Directorate for the Quality of Medicines & HealthCare, the Council of Europe, and the European Partnership for Alternative Approaches to Animal Testing jointly hosted an international conference entitled "The future of pyrogenicity testing: phasing out the rabbit pyrogen test". The conference aimed to show how the European Pharmacopoeia intends to remove the RPT from its texts by 2026, facilitate the use of MAT, and identify gaps in the suppression of RPT. The events contributed to a better understanding of the barriers to RPT replacement and acceptance of in vitro alternatives. Participants comprised stakeholders from Asia, Europe, and North America, including vaccine developers, contract laboratories, and regulators. Participants shared their replacement strategies and experiences with MAT implementation. They emphasised the need for continued cooperation between stakeholders and stressed the importance of international harmonisation of regulatory requirements to help accelerate MAT acceptance outside Europe. Despite the challenges, the willingness to eliminate the unnecessary use of RPT was common across all participants.

Monocyte Activation and Ageing Biomarkers in the Development of Cardiovascular Ischaemic Events or Diabetes in People with HIV.

We investigated whether blood telomere length (TL), epigenetic age acceleration (EAA), and soluble inflammatory monocyte cytokines are associated with cardiovascular events or diabetes (DM) in people living with HIV (PLHIV). This was a case-control study nested in the Spanish HIV/AIDS Cohort (CoRIS). Cases with myocardial infarction, stroke, sudden death, or diabetes after starting antiretroviral therapy were included with the available samples and controls matched for sex, age, tobacco use, pre-ART CD4 cell count, viral load, and sample time-point. TL (T/S ratio) was analysed by quantitative PCR and EAA with DNA methylation changes by next-generation sequencing using the Weidner formula. Conditional logistic regression was used to explore the association with cardiometabolic events. In total, 180 participants (94 cases (22 myocardial infarction/sudden death, 12 strokes, and 60 DM) and 94 controls) were included. Of these, 84% were male, median (IQR) age 46 years (40-56), 53% were current smokers, and 22% had CD4 count ≤ 200 cells/mm3 and a median (IQR) log viral load of 4.52 (3.77-5.09). TL and EAA were similar in the cases and controls. There were no significant associations between TL, EAA, and monocyte cytokines with cardiometabolic events. TL and EAA were mildly negatively correlated with sCD14 (rho = -0.23; p = 0.01) and CCL2/MCP-1 (rho = -0.17; p = 0.02). We found no associations between TL, EAA, and monocyte cytokines with cardiovascular events or diabetes. Further studies are needed to elucidate the clinical value of epigenetic biomarkers and TL in PLHIV.

Osteopontin Is an Integral Mediator of Cardiac Interstitial Fibrosis in Models of Human Immunodeficiency Virus Infection.

BACKGROUND: People with human immunodeficiency virus (HIV) have heightened incidence/risk of diastolic dysfunction and heart failure. Women with HIV have elevated cardiac fibrosis, and plasma osteopontin (Opn) is correlated to cardiac pathology. Therefore, this study provides mechanistic insight into the relationship between osteopontin and cardiac fibrosis during HIV infection. METHODS: Mouse embryonic fibroblasts (MEFs) modeled cardiac fibroblasts in vitro. Simian immunodeficiency virus (SIV)-infected macaques with or without antiretroviral therapy and HIV-infected humanized mice modeled HIV-associated cardiac fibrosis. RESULTS: Lipopolysaccharide-stimulated MEFs were myofibroblast-like, secreted cytokines, and produced Opn transcripts. SIV-infected animals had elevated plasma Opn at necropsy, full-length Opn in the ventricle, and ventricular interstitial fibrosis. Regression modeling identified growth differentiation factor 15, CD14+CD16+ monocytes, and CD163 expression on CD14+CD16+ monocytes as independent predictors of plasma Opn during SIV infection. HIV-infected humanized mice showed increased interstitial fibrosis compared to uninfected/untreated animals, and systemic inhibition of osteopontin by RNA aptamer reduced left ventricle fibrosis in HIV-infected humanized mice. CONCLUSIONS: Since Opn is elevated in the plasma and left ventricle during SIV infection and systemic inhibition of Opn reduced cardiac fibrosis in HIV-infected mice, Opn may be a potential target for adjunctive therapies to reduce cardiac fibrosis in people with HIV.

Monocyte antigen-presenting capacity to iNKT cells is influenced by the blood collection conditions.

It is widely accepted that different blood collection conditions, including anticoagulants, influence leukocyte phenotype and function. Buffy Coats originated from a donated whole blood bag unit are commonly used in immunological research as a source of leukocytes. They are a residual product of healthy donor whole blood processing. The preservative solution present in the blood bag unit and consequently in the derived Buffy Coat is Citrate-Phosphate-Dextrose (CPD), in which citrate is the anticoagulant. There is a lack of information on the possible difference in the functionality of leukocytes from Buffy Coats originated from a blood bag unit vs leukocytes isolated from blood collection tubes with various anticoagulants. Herein, we aimed at studying monocyte function when the monocytes are isolated from Buffy Coats originated from a blood bag unit vs blood collection tube containing EDTA, CPD with adenine (CPDA), or sodium citrate. The function of monocytes, isolated 20 h after blood collection, to present lipid antigens to invariant Natural Killer T (iNKT) cells was investigated. iNKT cells are activated by lipids bound to CD1d, a non-polymorphic MHC-class I-like molecule, present on the surface of antigen-presenting cells. A striking result showed that monocytes isolated from EDTA blood tubes have a lower capacity to present lipid antigens to iNKT cells than monocytes isolated from Buffy Coats originated from a blood bag unit. No differences were found between monocytes isolated from sodium citrate or CPDA and the ones isolated from Buffy Coats originated from a blood bag unit. This was accompanied by a decrease in viability of the EDTA-isolated monocytes. Expression of the surface markers CD1d and CD86 was higher for monocytes isolated from EDTA than those isolated from Buffy Coats. In conclusion, EDTA-containing blood tubes are not the ideal choice of anticoagulant for monocyte antigen presentation assays. We advise that the blood collection condition and the time between biospecimen collection and analysis should be carefully considered when designing experimental procedures.

Comparison of pyrogen assays by testing products exhibiting low endotoxin recovery.

The use of pyrogen tests to assess the risk of endotoxin in biological products has increased recently due to concerns of some regulatory authorities about products exhibiting low endotoxin recovery (LER). Manufacturers increasingly seek to reduce the use of animals unless essential to assure patient safety. The current study compares the ability of the monocyte activation test (MAT) and the bacterial endotoxin test (BET) to the rabbit pyrogen test (RPT) to detect endotoxin spikes in samples of products shown to exhibit LER. Product samples or water were spiked with endotoxin and held for three days or tested immediately in the BET, the RPT, and two variations of the MAT at the same time. Results show high sensitivity to endotoxin of both the BET and MAT, and much lower sensitivity of the RPT, indicating that much higher levels of reference standard endotoxin are required to induce pyrogenicity in the RPT than the 5 endotoxin units (EU) per kg common threshold. The results of the BET and MAT correlated well for the detection of endotoxin spike in water. We also show that LER (masking of endotoxin) found in the BET is also seen in the MAT and RPT, suggesting that the products themselves elicit a biological inactivation of spiked endotoxin over time, thereby rendering it less or non-pyrogenic. We conclude that the non-animal MAT option is a suitable replacement for the RPT to measure spiked endotoxin in biopharmaceuticals.

Monocyte adaptations in patients with obesity during a 1.5 year lifestyle intervention.

Background: Obesity is associated with chronic, low-grade inflammation, which is reflected in altered peripheral blood monocyte characteristics. The aim of this study was to analyze the monocyte subset composition (classical (CM), intermediate (IM) and non-classical monocytes (NCM)), and their inflammatory marker profile (CD14, CD16, CD36, CD45, CD64, CD300e, HLA-DR) in individuals with obesity during a 1.5 year combined lifestyle intervention (CLI), comprising healthy nutrition, increased exercise and behavioral changes. Methods: We analyzed monocyte subset counts and immunophenotypes in 73 individuals with obesity, and associated these to baseline body mass index (BMI) and waist circumference (WC). The measurements were repeated after 10 weeks and at the end of the intervention (1.5 years). Results: Generally, monocyte subset counts were not associated to BMI or WC at baseline, neither did monocyte counts change during the 1.5 year CLI. Immunophenotypically, higher baseline BMI and WC were associated to lower CD14 and higher CD300e expression by all subsets. During CLI there were remarkable changes in marker profiles: expression of CD14, CD36, CD45 and CD64 significantly decreased in CM and IM, as did CD16 (IM and NCM) (p<0.05). CD300e initially decreased after 10 weeks, but increased sharply at 1.5 years (all subsets). We observed no consistent associations between changes in monocyte characteristics and anthropometric changes. Conclusion: A 1.5 year CLI in individuals with obesity mediates persistent immunophenotypic adaptations related to cellular activation in blood monocytes, whereas changes in subset distribution are limited. Lifestyle-induced changes in the inflammatory profile of monocytes differ from the 'less-severe-obesity'-phenotype, suggesting a novel, 'post-weight-loss' monocyte setpoint.

Dual activation profile of monocytes is associated with protection in Mexican patients during SARS-CoV-2 disease.

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been one of the most catastrophic diseases observed in recent years. It has reported nearly 550 million cases worldwide, with more than 6.35 million deaths. In Mexico, an increased incidence and mortality of this disease were observed, where the immune response has been involved in the magnitude and severity. A critical version of the disease is accompanied by hyperinflammatory responses, with cytokine and defective cellular responses. A detailed understanding of the role of molecules and cells in the immune response during COVID-19 disease may help to generate effective protection mechanisms, improving those we already have. Here we analyzed blood samples obtained from patients at the Hospital Regional de Alta Especialidad de Ixtapaluca (HRAEI), Mexico, which were classified according to living guidance for clinical management of COVID-19 by the World Health Organization: asymptomatic, mild, severe, and critical disease. We observed increased interleukin (IL)-6 levels and a T-CD8+ and T-CD4+ cell reduction correlated with the critical disease version. Importantly, here, we described a significant reduction of CD11b+CD45highCD14low monocytes during severe disease, which displayed a non-classical profile, expressing IL-10, transforming growth factor (TGF)-ß, and indoleamine 2,3-dioxygenase (IDO)1 molecule. Moreover, CD11b+CD45highCD14low monocytes obtained from infected one-dose vaccinated patients (Pfizer® vaccine) who suffered minimal symptoms showed simultaneously a dual classical and no-classical profile expressing pro- and anti-inflammatory cytokines. These results suggest that blood monocytes expressing a dual pro- and anti-inflammatory profile might be a predictive marker for protection in the Mexican population during COVID-19 disease. KEY POINTS : • Exacerbated immune response is associated with COVID-19 severe disease. • Dual monocyte activation profile is crucial for predicting protection during COVID-19. • Vaccination is crucial to induce the dual activation profile in monocytes.

Remnant Cholesterol and Dyslipidemia Are Risk Factors for Guillain-Barré Syndrome and Severe Guillain-Barré Syndrome by Promoting Monocyte Activation.

Background: Guillain-Barré syndrome (GBS) is the most common severe acute paralytic neuropathy, with a mortality rate of 5% and permanent sequelae rate of 10%. Currently, the cause of GBS remains unclear. Therefore, we sought to determine potential predictors for GBS and its severity. Methods: A case-control study was performed at Tiantan Hospital in Beijing from January 2017 to December 2021. Laboratory and clinical characteristics were assessed in recruited GBS patients and healthy control individuals (matched by sex and age). The potential risk factors for GBS and severe GBS were assessed using a logistic regression analysis. The mRNA levels of toll-like receptor 4 (TLR4), toll-like receptor 2 (TLR2) and nuclear factor κB (NF-κB) in GBS patients and control PBMCs were detected by fluorescence quantitative PCR. THP-1 cells were costimulated with LPS and free cholesterol to demonstrate the effect of free cholesterol on monocyte activation. Results: A total of 147 GBS patients and 153 healthy individuals were included in the study. Logistic regression analyses showed that preceding infection, alcohol consumption, remnant cholesterol, homocysteine and the dyslipidemia index were correlated with a higher risk of GBS. In contrast, increased HDL cholesterol was correlated with a lower risk of GBS. Moreover, remnant cholesterol and the dyslipidemia index were significantly correlated with severe GBS. The mRNA levels of TLR4, TLR2 and NF-κB in the PBMCs of GBS patients were significantly higher than those of healthy individuals. LPS activated THP-1 cells, and free cholesterol treatment increased the expression of TLR4, TLR2, NF-κB and IL-1ß mRNA in LPS-activated THP-1 cells. Conclusion: Dyslipidemia was correlated with the risk of GBS and severe GBS. Remnant cholesterol may promote the activation of monocytes in GBS patients. It may be valuable to control lipid levels in the prevention of GBS and severe GBS.

Monocyte count and soluble markers of monocyte activation in people living with HIV and uninfected controls.

BACKGROUND: Monocytes play an important role in inflammation, and monocytosis and monocyte activation are features of chronic inflammation. We aimed to investigate if HIV status was associated with monocyte count and monocyte activation and to assess the relationship between monocyte count and monocyte activation markers and HIV-related factors. METHODS: Persons living with HIV (PLWH) with measured monocyte count and sCD14 and sCD163 were included from the Copenhagen Comorbidity in HIV infection (COCOMO) study and matched 1:5 on sex and age with uninfected controls. In addition, 74 uninfected individuals from COCOMO with measured sCD14 and sCD163 were included. Identical protocols and equipment were used to determine monocyte counts and monocyte activation in PLWH and uninfected controls. Linear regression adjusted for age, sex, smoking and waist-to-hip-ratio was used to analyze the association between possible risk factors and monocyte outcomes. RESULTS: We included 871 PLWH and 4355 uninfected controls. PLWH had - 0.021 [- 0.031 - 0.011] × 109/L) lower monocyte count than uninfected controls, and in adjusted analyses HIV status was independently associated with - 0.035 [- 0.045, - 0.025] × 109/L lower monocyte count. In contrast, PLWH had higher sCD163 and sCD14 concentrations than uninfected controls. After adjustment, HIV-status was associated with higher sCD14 and sCD163 concentrations (588 [325, 851] ng/ml, and 194 [57, 330] ng/ml, respectively). CONCLUSION: PLWH had lower monocyte counts than controls, but the absolute difference was small, and any clinical impact is likely limited. In contrast, concentrations of monocyte activation markers, previously implicated as drivers of non-AIDS comorbidity, were higher in PLWH than in controls.

The monocyte activation test detects potentiated cytokine release resulting from the synergistic effect of endotoxin and non-endotoxin pyrogens.

Pyrogens are classified in two groups, endotoxin pyrogens and non-endotoxin pyrogens (NEPs). The presence of either in parenteral pharmaceuticals or medical devices can cause severe harm to subjects, and when occurring in combination, synergistic potentiation effects can occur. As the standard in vitro pyrogen test, the Limulus Amebocyte Lysate (LAL) assay can detect LPS only, an endotoxin, but not NEPs. We tested whether the Monocyte Activation Test (MAT) that measures IL-6 induction, is suited for detecting synergistic pyrogen effects. Here we show that MAT reliably detects the NEPs heat-killed Staphylococcus aureus, R848 and lipoteichoic acid, in addition to LPS. When combinations of these pyrogens were tested, a potentiation of IL-6 production was seen beyond an additive effect, apparently reflecting on in-vivo synergisms. The current study therefore demonstrates that MAT not only is a reliable and reproducible assay for the sensitive detection of both endotoxin and non-endotoxin pyrogens, but also for identifying synergistic effects when parenteral drugs are contaminated with multiple pyrogens.

Macrophage Polarization Profiling on Native and Regenerated Silk Biomaterials.

We investigated the plasticity and polarization of THP-1 cells on native and regenerated silk-based biomaterials to address the basic paradigm of immune response. Here, we report redox kinetics, adhesion morphology, and nitric oxide release patterns to identify specific subtypes of macrophages at different time points. Water-annealed silk film and native fibrous braids from Bombyx mori silkworms showed higher anti-inflammatory cytokine profiles or M2 subtypes (as evidenced by the enhanced expression of interleukin-10, interleukin-13, and interleukin-4). Ethanol-treated Bombyx mori silk films and Antheraea mylitta braids exhibited higher levels of pro-inflammatory cytokines or the M1 subtype (as evidenced by enhanced expression of interleukin-1, interleukin-6, interleukin-8, interferon-γ, TNF-α, and GM-CSF) in contact with healthy THP monocytes for 14 days; such a long study is unprecedented. Cytokine microarray analysis revealed the transition (M0-M1, M1-M2), plasticity, and stable phenotype of THP-1 cells in a variable stage in contact with different physicochemical properties of silk-based biomaterials. The detailed immunogenicity in the context of the physicochemical properties of native and regenerative silk-based biomaterials will enable us to accurately predict the possibility of a pro-/anti-inflammatory response. It will helps to predict the in vivo reprogramming and avoid fibrosis formation to enhance their clinical translational potential.

Oral Enrichment of Streptococcus and its Role in Systemic Inflammation Related to Monocyte Activation in Humans with Cocaine Use Disorder.

Cocaine use is commonly associated with increased chronic systemic inflammation. However, the drivers for cocaine use-mediated systemic inflammation are not fully understood. In the current study, we recruited individuals with cocaine use disorder and healthy individuals who did not use cocaine and collected paired saliva and blood samples. The saliva samples were used to assess the oral microbiome, and the plasma samples were evaluated for 33 cytokines and chemokines. Cocaine users exhibited decreased saliva microbial diversities compared to non-users. Streptococcus was the only increased genus in the saliva from cocaine users, whereas several genera were decreased in cocaine users compared to non-users. Notably, cocaine users exhibited increased plasma levels of several monocyte activation markers, including monocyte chemoattractant protein (MCP)-4, macrophage inflammatory protein (MIP)-3α, macrophage-derived chemokine (MDC), and thymus and activation-regulated chemokine (TARC), all of which were correlated with increased saliva levels of three Streptococcus species. Furthermore, treatment with Streptococcus or its lipoteichoic acid preferentially activated primary human monocytes to produce proinflammatory cytokines and chemokines, such as MIP-3α and TARC, in vitro compared to controls. However, monocytes failed to produce these chemokines after exposure to cocaine or cocaine plus bacteria compared to medium or bacteria alone. This study revealed that chronic cocaine use-associated inflammation in the blood may result from increased oral Streptococcus and its effects on myeloid cell activation, but does not result from cocaine directly.