Interleukin-6 In Humans Research Articles

Model-Based Exploration of the Impact of Prophylactic Tocilizumab on IL-6 Dynamics in Multiple Myeloma Patients Receiving Teclistamab Treatment

Introduction: Teclistamab is the only approved B-cell maturation antigen (BCMA) × CD3 bispecific antibody (BsAb) with personalized, weight-based dosing for the treatment of patients with triple-class exposed relapsed/refractory multiple myeloma (RRMM).In the MajesTEC-1 study (NCT03145181 and NCT04557098), the incidence of all grade (mostly grade 1 or 2) cytokine release syndrome (CRS) was 72.1% (Moreau et al. 2022). The cytokine interleukin-6 (IL-6) is found to be increased in the serum of patients with CRS (Shimabukuro-Vornhagen et al. 2018). Tocilizumab is a humanized IL-6 receptor-inhibiting monoclonal antibody. As a competitive antagonist, tocilizumab inhibits the IL-6 pathway by competing with IL-6 for binding to IL-6 receptor (IL-6R), resulting in lower IL-6R receptor occupancy (RO) by IL-6, thereby blocking IL-6 signaling. By blocking IL-6R, tocilizumab also reduces IL-6R-mediated IL-6 clearance, which leads to an increase in serum IL-6 levels (Uchiyama et al. 2008). It has been published previously that a single dose of prophylactic tocilizumab reduced the overall incidence of CRS to 26% after teclistamab administration, which represents a 64% reduction compared to the CRS incidence observed in MajesTEC-1 (van de Donk et al. 2023). A mechanism-based PK/PD model was used to evaluate the impact of tocilizumab prophylactic treatment on the soluble IL-6R (sIL-6R), IL-6 and the duration of the blockade of IL-6 signaling pathway in the patients following teclistamab treatment. Methods: A mechanism-based PK/PD model was built by using reported tocilizumab PK parameters and sIL-6R target engagement. The time course of IL-6R RO for patients receiving prophylactic tocilizumab following teclistamab treatment was estimated from the PK profiles of tocilizumab and competitive binding kinetics. Among the patients with evaluable serum IL-6 levels, the highest peak serum IL-6 concentration in the patients who didn't have CRS (N=9) from prophylactic tocilizumab cohort of MajesTEC-1 was selected as the worst-case scenario. The IL-6R RO in patients receiving prophylactic tocilizumab in the worst-case scenario was characterized by model simulations and the results were compared to the calculated IL-6R RO in the cohorts following teclistamab treatment without prophylactic tocilizumab (N=40). Results: Time course of serum IL-6 levels following teclistamab treatment showed higher and earlier induction in the cohort with tocilizumab prophylaxis compared to the cohort without tocilizumab prophylaxis. Among the patients who received tocilizumab prophylactic treatment, the median peak serum IL-6 level was 208.6 pg/mL and the highest peak serum IL-6 level was 1701.8 pg/mL in patients who didn't have CRS. The model simulation results showed that a single dose of tocilizumab at 8 mg/kg IV given prophylactically could lower the IL-6R RO by IL-6. In a patient with 1700 pg/mL of serum IL-6 treated with tocilizumab, IL-6R RO was maintained below the level of RO achieved with 10 pg/mL of serum IL-6 in the absence of tocilizumab for approximately 10 days. An IL-6 level of 10 pg/mL was considered as a representative value in the patients who did not have CRS following teclistamab at the approved dosing regimen without prophylactic tocilizumab, as more than half (58%) of these patients showed peak serum IL-6 level below 10 pg/mL. The duration of IL-6R RO reduction covers the two step-up doses (SUD) and the first full treatment dose according to the teclistamab approved dosing schedule. Conclusions: The modeling and simulation results showed that a single dose of tocilizumab given prophylactically at 8 mg/kg could block IL-6R RO for approximately 10 days following the 1 st step up dose of teclistamab. The results further support this approach for lowering overall risk of CRS during the SUD schedule in multiple myeloma patients treated with teclistamab.

Higher circulating Vitamin B12 is associated with lower levels of inflammatory markers in individuals at high cardiovascular risk and in naturally aged mice.

Vitamin B12 is an essential nutrient that is involved in numerous physiological processes, and its deficiency can lead to various complications, including neurological and haematological disorders. Some studies have suggested that vitamin B12 may have anti-inflammatory effects, but the mechanisms underlying this relationship are not yet fully understood. We investigated the relationship between circulating vitamin B12 and inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP). The association of peripheral levels of vitamin B12 with IL-6 and CRP was assessed in 136 human samples from a high cardiovascular risk population. To corroborate the results from the human trial, the analysis was replicated in naturally aged mice. Individuals with higher serum levels of vitamin B12 showed lower concentrations of IL-6 and CRP after adjustment for potential confounders, and an inverse association was also found between serum IL-6 and vitamin B12 levels in naturally aged mice. That circulating vitamin B12 was inversely associated with IL-6 and CRP in humans and with IL-6 in mice suggests that it may exert an anti-inflammatory effect through modulation of these pro-inflammatory molecules. This article is protected by copyright. All rights reserved.

Interleukin-6 Drives Mitochondrial Dysregulation and Accelerates Physical Decline: Insights From an Inducible Humanized IL-6 Knock-In Mouse Model.

Chronic activation of inflammatory pathways (CI) and mitochondrial dysfunction are independently linked to age-related functional decline and early mortality. Interleukin 6 (IL-6) is among the most consistently elevated chronic activation of inflammatory pathways markers, but whether IL-6 plays a causative role in this mitochondrial dysfunction and physical deterioration remains unclear. To characterize the role of IL-6 in age-related mitochondrial dysregulation and physical decline, we have developed an inducible human IL-6 (hIL-6) knock-in mouse (TetO-hIL-6mitoQC) that also contains a mitochondrial-quality control reporter. Six weeks of hIL-6 induction resulted in upregulation of proinflammatory markers, cell proliferation and metabolic pathways, and dysregulated energy utilization. Decreased grip strength, increased falls off the treadmill, and increased frailty index were also observed. Further characterization of skeletal muscles postinduction revealed an increase in mitophagy, downregulation of mitochondrial biogenesis genes, and an overall decrease in total mitochondrial numbers. This study highlights the contribution of IL-6 to mitochondrial dysregulation and supports a causal role of hIL-6 in physical decline and frailty.

Pharmacokinetics, pharmacodynamics, safety, and immunogenicity of Gerilimzumab (GB224), a recombinant humanized interleukin-6 monoclonal antibody, in healthy Chinese adults: A randomized controlled dose–escalation study

ABSTRACT Objectives This study aimed to investigate the safety, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of Gerilimzumab (GB224), a recombinant humanized IgG1λ monoclonal antibody against interleukin-6, in healthy Chinese adults. Methods Fifty-eight subjects were randomly assigned to receive a single subcutaneous dose of 2, 5, 10, 15, 20, 30 mg GB224 or placebo. Safety assessments were performed, and blood samples were collected for PK, PD, and immunogenicity analyses during a follow-up of 112 days. Results The most frequent adverse event was decreased fibrinogen (43.1%). GB224 was absorbed relatively fast with a median Tmax of 48 h (24–168 h) but eliminated slowly with a long mean half-life (839.38–981.63 h). Dose proportionality was shown to be in the dose range of 10–30 mg. A dose-dependent increase in serum interleukin-6 concentration from baseline was observed in the subjects receiving GB224. Only two subjects tested positive for antidrug antibodies after administration of GB224. Conclusion GB224 had a well-tolerated safety profile, desirable PK, and a low immunogenicity following a single-dose subcutaneous administration in healthy Chinese subjects. These findings warrant further investigation.

Does Tocilizumab Influence the Outcome of Patients with COVID-19 Pneumonia Compared to the Standard Therapy? Retrospective Analysis of Data Obtained during Phase I COVID Pandemic

BACKGROUND: No gold standard therapy was approved globally for COVID-19 pneumonia to the date of this study. The pathophysiology of SARS-CoV-2 infection displayed the predominance of hyperinflammation and immune dysregulation in inducing multiorgan damage. Therefore, the potential benefits of both immune modulation and suppression in COVID-19 have been extensively discussed as a modality to control cytokine release syndrome (CRS). Abnormally high levels of interleukin-6 (IL-6) are a common finding in COVID-19 patients with pneumonia and acute respiratory distress syndrome, so the use of IL-6 antagonist was tested as a therapeutic option in controlling the disease. Tocilizumab is a recombinant humanized anti-human IL-6 receptor monoclonal antibody that can specifically bind the membrane-bound IL-6 receptor and soluble IL-6 receptor, thereby inhibiting signal transduction. Tocilizumab is currently FDA approved for the management of rheumatoid arthritis, giant cell arthritis, polyarticular juvenile idiopathic arthritis, and systemic juvenile idiopathic arthritis. This study is a retrospective analysis of data polled during Phase I of COVID pandemic, adopted by the isolation hospital of Kasr Al-Ainy Medical School, Cairo University, during the period from May to September 2020. AIM: The aim of this study is to evaluate tocilizumab influence in the outcome; in terms of reducing the hospital stay, risk and duration of mechanical ventilation (invasive and noninvasive), mortality, and the incidence of complications related to drugs use (secondary bacterial infection and GIT bleeding) in patients with moderate-to-severe COVID-19. METHODS: This retrospective, observational cohort study included adults (between 18 and 80 years) with moderate-to-severe COVID-19 pneumonia, who were admitted to isolation hospital of Kasr Al-Ainy Medical School, Cairo University, between May and September 2020. We segregated the patients into two groups: Group A: In addition to the standard care protocol according to the local guidelines of the Egyptian Ministry of Health and Population in that period (supplemental oxygen, steroids in a dose of 1–2 mg/kg methylprednisolone for 5–10 days, broad-spectrum antibiotics, vitamins, and prophylactic dose of anticoagulation with low-molecular-weight heparin, proton-pump inhibitor, and poly-vitamins), they received tocilizumab intravenously in a dose of 8 mg/kg bodyweight (up to a maximum of 800 mg per dose), divided in two shots 12–24 h apart. Group B: Those received the standard care protocol alone, noting that guidelines were adjusted later on according to the updated scientific publications and WHO recommendations. The primary endpoint was to evaluate the effect of different regimens in controlling the disease, the need for mechanical ventilation and its duration (either invasive or non-invasive), length of ICU stay, hospital stay, and in-hospital mortality. Comparisons between quantitative variables were done using the non-parametric Mann–Whitney U-test. For comparison of serial measurements within each patient, the non-parametric Wilcoxon signed-rank test was used. For comparing categorical data, Chi-square (2) test was performed. Exact test was used instead when the expected frequency was <5. Correlations between quantitative variables were done using Spearman correlation coefficient. RESULTS: During this period, 166 patients were admitted to ICU, suffering from severe hypoxemia with moderate to severe COVID-19 pneumonia, 10 of them were excluded (three were over 80 years old, other three had advanced stages of malignancy, two were on steroids therapy and non-invasive home ventilation due to chronic chest condition, and two were presented with MODs and deceased in <48 h from admission), thus, 156 were included in the study. Group A: Seventy-six patients (49%) received tocilizumab in addition to standard therapy, Group B: Eighty patients (51%) received standard therapy only. In Group A, the mean length of ICU stay was 8.96 days with mean length of hospital stay 13.76, compared to mean length of ICU stay 9 days in Group B (p = 0.57) and mean length of hospital stay 12.46 days (p = 0.117). In Group A, 35 patients (46%) needed non-invasive mechanical ventilation (MV),12 patients of the 35 needed invasive MV in later stage, compared to 26 patients (32%) in Group B, 14 patients of the 26 needed invasive MV in later stage (p = 0.16). In Group A, 14 patients (18.4%) needed invasive mechanical ventilation, compared to 19 patients (23.7%) in Group B (p = 0.213). In Group A, 6 (7.9%) of 76 patients died, compared to 13 (16.3%) of 80 in Group B p = 0.11. The incidence of secondary bacterial infection in Group A was 16 patients (21%) compared to 21 (26%) in Group B (p = 0.44). CONCLUSION: In this study, we did not detect statistical difference in both groups of patients coming during CRS-associated COVID-19 pneumonia, regarding (ICU stay, need for and length of MV, the incidence of secondary bacterial infection, and in-hospital mortality) for COVID-19 moderate-to-severe pneumonia.

The Role of IL-6 in Inflammatory Reaction during Coronavirus-19 Infection: A Review

Interleukin 6 (IL-6) is an interleukin that works as a pro-inflammatory cytokine and as an anti-inflammatory myokine. The production of IL-6 in humans is under genetic control. IL-6 is a pleiotropic cytokine created in response to tissue injury and infections. IL-6 is one of the basic cytokines after stimulated macrophages. Hence, control of systemic IL-6 levels in SARS-CoV-2 infected patients may be a consideration for COVID-19 disease. This review will focus on the role of IL-6 in diagnosis and follow up of infection in addition to being the target for treatment.

Characterization of a Mouse Model of Inducible Frailty: The Humanized IL-6 Mouse

The cytokine interleukin-6 (IL-6) has pleiotropic effects in aging and is elevated in frail older adults. We have developed a conditional mouse model to better characterize the role of IL-6 in promoting frailty and age-related mitochondrial dysregulation. The human IL-6 (hIL-6) knock-in mouse (TetO-hIL6) was developed utilizing CRISPR/Cas9 technology with transgene donor vector containing a tetracycline response element promoter driving expression of hIL-6 cDNA. Male TetO-hIL6 mice were treated with doxycycline-containing water for six weeks starting at 8 months old. RNAseq analysis of whole blood demonstrated significant upregulation of pro-inflammatory related markers at 6 weeks compared to baseline and upregulated cell proliferation and metabolism pathways. Physical testing of TetO-hIL6 mice before and after hIL-6 induction demonstrated decreased grip strength (p =0.003), decreased running capacity (p = 0.02), and 40% increase in falls off of the treadmill (p = 0.001). Induced mice also demonstrated decreased basal body temperature (p < 0.001). Given the significant dysregulation of metabolism-related genes in RNAseq analysis and changes in basal body temperature following hIL-6 induction, we next performed untargeted metabolomics on plasma from mice at baseline and 6 weeks post-induction to better evaluate metabolic changes associated with hIL-6 elevation. We found changes in key serum metabolites, including circulating adenosine triphosphate (56% reduction, p = 0.02), pyruvate (35% reduction, p = 0.0006), alpha-ketoglutarate (47% reduction, p = 0.04), and succinate (306% increase, p = 0.001). The TetO-hIL6 mouse model allows for induction of hIL-6 at various timepoints across the lifespan and demonstrates features of a frailty phenotype.

Use of Chloroquine and Hydroxychloroquine in COVID-19 and Cardiovascular Implications: Understanding Safety Discrepancies to Improve Interpretation and Design of Clinical Trials.

Author(s): Oren, Ohad; Yang, Eric H; Gluckman, Ty J; Michos, Erin D; Blumenthal, Roger S; Gersh, Bernard J

Effective treatment of severe COVID-19 patients with tocilizumab

After analyzing the immune characteristics of patients with severe coronavirus disease 2019 (COVID-19), we have identified that pathogenic T cells and inflammatory monocytes with large amount of interleukin 6 secreting may incite the inflammatory storm, which may potentially be curbed through monoclonal antibody that targets the IL-6 pathways. Here, we aimed to assess the efficacy of tocilizumab in severe patients with COVID-19 and seek a therapeutic strategy. The patients diagnosed as severe or critical COVID-19 in The First Affiliated Hospital of University of Science and Technology of China (Anhui Provincial Hospital) and Anhui Fuyang Second People's Hospital were given tocilizumab in addition to routine therapy between 5 and 14 February 2020. The changes of clinical manifestations, computerized tomography (CT) scan image, and laboratory examinations were retrospectively analyzed. Fever returned to normal on the first day, and other symptoms improved remarkably within a few days. Within 5 d after tocilizumab, 15 of the 20 patients (75.0%) had lowered their oxygen intake, and 1 patient needed no oxygen therapy. CT scans manifested that the lung lesion opacity absorbed in 19 patients (90.5%). The percentage of lymphocytes in peripheral blood, which decreased in 85.0% of patients (17/20) before treatment (mean, 15.52 ± 8.89%), returned to normal in 52.6% of patients (10/19) on the fifth day after treatment. Abnormally elevated C-reactive protein decreased significantly in 84.2% of patients (16/19). No obvious adverse reactions were observed. All patients have been discharged on average 15.1 d after giving tocilizumab. Preliminary data show that tocilizumab, which improved the clinical outcome immediately in severe and critical COVID-19 patients, is an effective treatment to reduce mortality.

Characterization of tree shrew (Tupaia belangeri) interleukin-6 and its expression pattern in response to exogenous challenge.

Tree shrews, one of the closest relatives of primates, have attracted increasing attention as a model of human diseases, particularly for viral infections. As the first line of defense against microbial pathogens, the innate immune system is crucial in tree shrews. Interleukin-6 (IL-6) is important in the pathophysiology of infection, inflammation and cancer, where it promotes disease development or sustains immune reactions. The present study aimed to obtain further insight into the tree shrew IL-6 (tsIL-6) system, and the function of tsIL-6 in the antiviral and antibacterial response. In the present study, the mRNA and genomic sequence of the tsIL-6 gene were characterized, and the tissue distribution and expression profile of this gene were analyzed in response to lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid (poly I:C) treatment. The full-length tsIL-6 mRNA consisted of 1,152 bp with an open reading frame of 627 bp encoding 208 amino acids, a 5′-untranslated region (UTR) of 62 bp, and a 3′-UTR of 436 bp. The genome sequence of the tsIL-6 gene was 5,265 bp in length, comprising of five exons and four introns. The predicted tsIL-6 protein contained a 25-amino-acid-long signal peptide and a conserved IL-6 domain. Phylogenetic analysis based on the coding sequences revealed that tsIL-6 was closely related to IL-6 in humans. Residues crucial for receptor binding were completely conserved in the tree shrew protein. Reverse transcription-polymerase chain reaction analysis revealed that tsIL-6 mRNA was expressed in all examined tissues of healthy tree shrews, with high levels in the muscle and spleen. Following poly I:C challenge, the expression levels of tsIL-6 were upregulated in four tissues associated with immune system, the liver, spleen, kidney and intestine. Taken together, the molecular and bioinformatics analyses based on the IL-6 sequence revealed that the tree shrew has a close phylogenetic association with humans. These results provide insight for future investigations on the structure and function of tsIL-6.

Diurnal Variation of Circulating Interleukin-6 in Humans: A Meta-Analysis.

The pleiotropic cytokine interleukin-6 (IL-6) has been proposed to contribute to circadian regulation of sleepiness by increasing in the blood at night. Earlier studies have reported diurnal variation of IL-6, but phase estimates are conflicting. We have therefore performed a meta-analysis on the diurnal variation of circulating IL-6. Studies were included if they reported IL-6 in plasma or serum recorded at least twice within 24 hours in the same individual. A systematic search resulted in the inclusion of 43 studies with 56 datasets, for a total of 1100 participants. Individual participant data were available from 4 datasets with a total of 56 participants. Mixed-effects meta-regression modelling confirmed that IL-6 varied across the day, the most conspicuous effect being a trough in the morning. These results stand in contrast to earlier findings of a peak in the evening or night, and suggest that diurnal variation should be taken into account in order to avoid confounding by time of day in studies of IL-6 in plasma or serum.

Spotlight on sirukumab for the treatment of rheumatoid arthritis: the evidence to date.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease primarily affecting synovial joints and is characterized by persistent high-grade systemic inflammation. Proinflammatory cytokines, particularly interleukin-6 (IL-6), are of crucial importance in the pathogenesis of the disease, driving both joint inflammation and extra-articular comorbidities. Tocilizumab, a humanized IL-6 receptor-inhibiting monoclonal antibody, has been the first, and, to date, the only, IL-6 inhibitor approved for the treatment of RA. Many studies have demonstrated the potency and effectiveness of tocilizumab in controlling disease activity and radiological progression of RA. These successful results have encouraged the development of novel IL-6 inhibitors, among which a promising agent is sirukumab (SRK), a human anti-IL-6 monoclonal antibody currently under evaluation in Phase II/III studies in patients with RA, systemic lupus erythematosus, giant-cell arteritis, and major depressive disorder. The evidence to date indicates SRK as an effective and well-tolerated new therapeutic tool for patients with active RA, with some preliminary data suggesting a specific beneficial impact on relevant systemic complications associated with the disease, such as depression and cardiovascular disease. Conversely, although pathophysiological considerations make plausible the hypothesis that IL-6 blockade with SRK may also be beneficial in the treatment of many diseases other than RA (either autoimmune or not), available clinical data in patients with systemic lupus erythematosus do not seem to support this view, also giving rise to potentially relevant concerns about drug safety. If large Phase III clinical trials currently in progress in patients with RA confirm the efficacy and tolerability of SRK, then in the long term, this drug could, in the near future, occupy a place in the treatment of the disease, potentially also opening the doors to a more extended use of SRK in a wide range of disorders in which IL-6 plays a key pathogenic role.

IL-6 Blockade as a Therapeutic Approach for Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a recessive X-linked form of genetic muscle disease affecting approximately 1 in 3500 males (Flanigan, 2014). Boys with DMD carry mutations in the dystrophin gene resulting in defective or absent dystrophin protein. Both skeletal and cardiac muscles undergo progressive damage in this disease, with most boys confined to wheelchairs by age 12. There is currently no cure for DMD and affected patients die from respiratory failure, cardiomyopathy, or other complications at an average age of 25 years. In this issue of EBioMedicine, Pelosi and colleagues present evidence that blockade of interleukin-6 (IL-6) ameliorates muscle destruction and weakness in a mouse model of DMD and suggest that this may represent a novel therapeutic approach in humans. In DMD, dystrophin deficiency disrupts the dystrophin–glycoprotein complex, leading to muscle fiber necrosis as well as a prominent inflammatory response. Although the inflammatory response may play a role in muscle repair, accumulating evidence suggests that it also contributes to muscle damage (Spencer and Tidball, 2001). In the 1970s, recognition of this inflammatory response prompted Drachman and colleagues to treat DMD patients with glucocorticoids (Drachman et al., 1974). The improvements these investigators noted in some DMD patients in an open-label trial have subsequently been confirmed in randomized, placebo-controlled clinical trials (Manzur et al., 2008). However, glucocorticoids, which remain the only available treatment for DMD, have relatively modest effect on the course of this fatal disease. Furthermore, these drugs have significant side effects including weight gain, osteoporosis, and increased risk of infection. Clearly, more effective and safer treatments for DMD are desperately needed. In an article in this issue of EBioMedicine, Pelosi and colleagues observe that the inflammatory cytokine IL-6 is expressed at high levels in the serum of boys with DMD as well as in inflammatory cells infiltrating their muscle tissue. Moreover, serum IL-6 levels were increased in untreated DMD patients compared to those receiving treatment with glucocorticoids. Taken together, these observations suggested that IL-6 might play a role in mediating muscle damage through the inflammatory response. In order to further study the possible role of IL-6 in mediating muscle damage, these investigators utilized the mdx mouse model of DMD. These mice lack functional dystrophin and, like boys with DMD, develop a progressive muscular dystrophy that includes a prominent inflammatory response. As in boys with DMD, Pelosi and colleagues demonstrated that circulating levels of IL-6 are increased and cells expressing high levels of IL-6 infiltrate the diaphragm muscles of mdx mice. To test whether blockade of IL-6 would ameliorate the dystrophic process in mdx mice, these mice were treated with an antibody recognizing the IL-6 receptor. Compared to untreated mdx mice, mice treated with the neutralizing antibody had decreased myofiber necrosis, improved functional performance after exercise on a treadmill, and evidence of a decreased inflammatory response in their muscle tissue. Based on their findings, Pelosi and colleagues suggest that IL-6 inhibitors, which are already approved for children with systemic juvenile idiopathic arthritis, should be considered for use in boys with DMD. However, optimism about their potential effectiveness is tempered by at least five considerations. First, another recent study by Kostek et al. showed that IL-6 blockade increased muscle inflammation and did not significantly improve muscle function in mdx mice (Kostek et al., 2012). These conflicting results may be due to differences in the dosing regimens used in each study. If that's the case, it remains unclear what the appropriate dosing regimen would be for DMD patients. Second, boys with DMD frequently die as a result of cardiomyopathy and the effect of IL-6 on cardiac muscle has not been studied. Third, in addition to promoting a potentially harmful inflammatory milieu, IL-6 has also been reported to play a role in muscle regeneration by promoting myoblast differentiation (Serrano et al., 2008); any therapeutic intervention aimed at blocking IL-6 in humans should consider this dual role of IL-6. Fourth, although mdx mice have been used extensively to understand the pathophysiology of DMD, they have limitations as a model for testing the effectiveness of therapeutic interventions (Partridge, 2013). Indeed, the literature includes numerous examples of drugs that improved outcomes in mouse models but did not have a similar effect in humans. And finally, any therapy for DMD that does not involve repletion of dystrophin is unlikely to cure this fatal disease. Despite these caveats, IL-6 blockade certainly warrants further study as a potential treatment modality for patients with DMD.

Multidisciplinary approach to the treatment of cardiac AA amyloidosis and aortic stenosis due to Castleman's disease: A hybrid therapy with tocilizumab and aortic valve replacement

A 67-year-old female patient with multicentric Castleman's disease (MCD) was admitted to our hospital with syncope on exertion. She previously had episodes of chronic fatigue, weight loss, prolonged fever, and skin rash accompanied by anemia, polyclonal hypergammaglobulinemia, and elevated inflammatory markers. Computed tomography showed multiple lymphadenopathies. The diagnosis of MCD with cutaneous involvement was made in 2010 based on the clinical manifestations and skin biopsy histopathological findings, which showed massive infiltration of polyclonal plasma cells in the dermis [ 1 Casper C. The aetiology and management of Castleman disease at 50 years: translating pathophysiology to patient care. Br J Haematol. 2005; 129: 3-17 Crossref PubMed Scopus (290) Google Scholar , 2 Munoz J. Naing A. Qi M. Kurzrock R. Cutaneous Castleman disease. Br J Haematol. 2012; 157: 652 Crossref PubMed Scopus (5) Google Scholar ]. Comorbidities such as viral infections, collagen diseases, and other malignancies were excluded. She simultaneously had renal impairment because of secondary AA amyloidosis due to MCD, which was diagnosed by renal biopsy based on multiple AA-type amyloid glomerular deposits. Fortunately, following the administration of tocilizumab, a humanized monoclonal interleukin-6 receptor antibody [ [3] Dubrey S.W. Hawkins P.N. Falk R.H. Amyloid diseases of the heart: assessment, diagnosis, and referral. Heart. 2011; 97: 75-84 Crossref PubMed Scopus (136) Google Scholar ], the patient achieved a stable disease status concomitant with improved clinical and laboratory manifestations (decrease in C-reactive protein from 10.0 mg/dL to 0.2 mg/dL and serum creatinine from 3.4 mg/dL to 2.0 mg/dL).

Short-term acetaminophen consumption enhances the exercise-induced increase in Achilles peritendinous IL-6 in humans

Through an unknown mechanism, the cyclooxygenase inhibitor and antipyretic acetaminophen (APAP) alters tendon mechanical properties in humans when consumed during exercise. Interleukin-6 (IL-6) is produced by tendon during exercise and is a potent stimulator of collagen synthesis. In nontendon tissue, IL-6 is upregulated in the presence of cyclooxygenase inhibitors and may contribute to alterations in extracellular matrix turnover, possibly due to inhibition of prostaglandin E2 (PGE2). We evaluated the effects of APAP on IL-6 and PGE2 in human Achilles peritendinous tissue after 1 h of treadmill exercise. Subjects were randomly assigned to a placebo (n = 8, 26 ± 1 yr) or APAP (n = 8, 25 ± 1 yr) group. Each subject completed a nonexercise and exercise experiment consisting of 6 h of microdialysis. Drug (APAP, 1,000 mg) or placebo was administered in a double-blind manner during both experiments. PGE2 and IL-6 were determined via enzyme immunoassay and APAP via high-performance liquid chromatography. In subjects given APAP, peritendinous APAP levels increased to 4.08 ± 0.65 μg/ml (P < 0.05). PGE2 did not increase with exercise in either group (P > 0.05), nor was PGE2 significantly reduced in the APAP group. IL-6 levels increased with exercise in both groups (P < 0.05), but this increase was greater in the APAP group (P < 0.05). Our findings suggest that APAP enhances tendon IL-6 production after exercise. Peak levels of APAP obtained in the peritendinous space were twofold lower than values reported in plasma or skeletal muscle. These findings provide insight into the effects of APAP on tendon and provide novel information on the kinetics of APAP in tendon tissue after oral APAP consumption.

Prostaglandin E2 induces transcription of skeletal muscle mass regulators interleukin-6 and muscle RING finger-1 in humans

Cyclooxygenase (COX) inhibiting drugs augment muscle mass and strength improvements during resistance exercise based treatment of sarcopenia in older individuals. Initial evidence suggests a potential mechanism of COX inhibitor blunted prostaglandin (PG) E2 stimulation of interleukin (IL)-6 and the ubiquitin ligase MuRF-1, reducing their inhibition on muscle growth. The purpose of this investigation was to determine if PGE2 stimulates IL-6 and MuRF-1 transcription in skeletal muscle. Muscle biopsies were obtained from 10 young individuals and incubated ex vivo with PGE2 or control and analyzed for IL-6 and MuRF-1 mRNA levels. PGE2 upregulated (P<0.05) expression of both IL-6 (195%) and MuRF-1 (51%). A significant relationship was found between IL-6 and MuRF-1 expression after incubation with PGE2 (r=0.77, P<0.05), suggesting regulation through a common pathway. PGE2 induces IL-6 and MuRF-1 transcription in human skeletal muscle, providing a mechanistic link between COX inhibiting drugs, PGE2, and the regulation of muscle mass.

Effect of flavonoids on circulating levels of TNF-α and IL-6 in humans: A systematic review and meta-analysis

Epidemiological or in vitro evidence suggests a potential role for flavonoids as anti-inflammatory agents; we investigated the effect of flavonoids-rich foods or supplements on tumor necrosis factor- alpha (TNF-α) and interleukin-6 (IL-6) in long-term placebo-controlled human intervention trials. From 110 human intervention studies selected (MEDLINE, EMBASE, CHORANE, and FSTA databases), 32 long-term placebo-controlled trials were suitable for meta-analysis. After sensitivity analysis, seven studies imputed of bias were excluded and 25 studies were analyzed (TNF-α, n = 2404; IL-6, n = 2174). Levels of TNF-α decreased after flavonoid consumption in the fixed model only (mean difference (MD) (95% CI): -0.098 (-0.188, -0.009), p = 0.032), but metaregression results showed that neither higher dose, nor a longer duration of intervention were associated with a greater effect size. Subgroup analysis did not reveal any significant effect for quercetin and soy, but other sources (red wine, pomegranate, and tea extracts) showed a significant effect size both in fixed (MD (95% CI): TNF-α -0.449 (-0.619, -0.280), p < 0.001; IL-6 -0.346 (-0.612, -0.079), p = 0.011) and random (MD (95% CI): TNF-α -0.783 (-1.476, -0.090), p = 0.027; IL-6, -0.556 (-1.062, -0.050), p = 0.031) effect models. High-quality placebo-controlled trials are needed in order to identify flavonoids as the active ingredients.

The social environment and IL-6 in rats and humans

Inflammatory cytokine levels predict a wide range of human diseases including depression, cardiovascular disease, type 2 diabetes, autoimmune disease, general morbidity, and mortality. Stress and social experiences throughout the lifecourse have been associated with inflammatory processes. We conducted studies in humans and laboratory rats to examine the effect of early life experience and adult social position in predicting IL-6 levels. Human participants reported family homeownership during their childhood and current subjective social status. Interleukin-6 (IL-6) was measured from oral mucosal transudate. Rats were housed in groups of three, matched for quality of maternal care received. Social status was assessed via competition for resources, and plasma IL-6 was assessed in adulthood. In both humans and rats, we identified an interaction effect; early social experience moderated the effect of adult social status on IL-6 levels. Rats that experienced low levels of maternal care and people with low childhood socioeconomic status represented both the highest and lowest levels of IL-6 in adulthood, depending on their social status as young adults. The predicted interaction held for non-Hispanic people, but did not occur among Hispanic individuals. Adversity early in life may not have a monotonically negative effect on adult health, but may alter biological sensitivity to later social experiences.

Source and kinetics of interleukin-6 in humans during exercise demonstrated by a minimally invasive model

The objective of this study was to use a novel and non-invasive model to explore whether: (1) exercise-induced increases in systemic levels of interleukin-6 (IL-6) and other cytokines can be ascribed to local production in working muscle; and (2) how acute release of retained blood from an exercised limb impacts on metabolites in the systemic circulation. On two experimental days, at least 3 weeks apart, six healthy moderately trained male subjects performed one-legged knee-extensor exercise for 2 h at 60% of their maximal workload. On one occasion venous outflow from the exercised leg was inhibited for 18 min by inflating a cuff around the thigh as proximally as possible immediately following exercise. On the control occasion venous outflow was not inhibited. Venous blood samples were collected from an arm vein at 2-min intervals after exercise. During inhibition of venous outflow from the exercised leg systemic plasma levels of IL-6 decreased within minutes to near pre-exercise levels, whereas plasma glucose levels increased to higher levels than without the cuff. After release of the cuff, systemic levels of IL-6 increased rapidly to match levels on the control occasion. On release of the cuff, plasma levels of free fatty acids (FFAs) declined more than without the cuff. In conclusion, the observed increase in systemic IL-6 plasma concentrations during exercise can be attributed to release from the working limb. Other potential sources of IL-6 outside the working limb do not contribute significantly to the increase in plasma IL-6 levels during exercise.

Development of 99mTcHYNIC-Tocilizumab as Imaging Agent In Multiple Myeloma

AbstractAbstract 4081 Introduction:Multiple myeloma (MM) accounts for 10% of hematological malignancies and 1% of cancer. It represents the second most common hematologic malignancy. The disease is characterised by plasma cell infiltration of the bone marrow, osteolytic bone lesions and the presence of a monoclonal paraprotein in the serum or urine. Interleukin-6 (IL-6) is a key molecule in the pathogenesis of MM. Its secretion occurs from the tumoral plasma cell as well as from the microenvironment. This results in myeloma cell proliferation. Tocilizumab, a humanized anti IL-6 receptor monoclonal antibody that blocks IL-6 cell-to-cell signaling, is currently being studied in MM. Most MM patients experience bone lesions. In spite of the new imaging techniques, the distinction between malignant and benign lesions remains sometimes difficult in clinical practice. The development of a more specific imaging agent may improve the accuracy of this diagnosis. Objective:Development of 99mTcHYNIC-Tocilizumab conjugate. Chemical and biological evaluation as a potential imaging agent in multiple myeloma. Methodology:10 mg Tocilizumab (Roche) were added to 20 mg HYNIC in NaHCO3 1M, incubated for 30 min at room temperature and purified by means of PD10 column. 1 ml fractions were measured at 280nm. Conjugation of HYNIC-Tocilizumab was evaluated by mass spectrometry MALDITOF and acrylamide gel electrophoresis. 20 uL Tricine/stannous chloride in a 1:1 mass relation were added to 1 mg HYNIC-Tocilizumab in 100 uL of 0.9% NaCl. 2 mL of a solution containing 370 MBq 99mTcO4- was added. Radiochemical purity was controlled by three chromatographic systems: ITLC/NaCl 0.9%, Whatman 1MM/MEK, ITLC in BSA/EtOH-NH3-H2O (2:1:5) as stationary and mobile phase, respectively. Binding to IL-6 receptor in U266 myeloma cells was evaluated in vitro at 15, 30, 60 and 120 min.Tocilizumab was derivatized with FTIC and purified by PD10 column. Laser scanning confocal microscopy was done with an excitation/emission wavelength of 488/530 nm. Fluorescent images were obtained. Biodistribution studies were performed at 24 h in CD1 normal mice (n=3). Each mice was injected with 37 MBq of 99mTcHYNIC-Tocilizumab and sacrificed 24 hs after injection. Organs of interest were collected. Results:Mass spectroscopy MALDITOF (MH+Tocilizumab 147626 Da, M+HYNIC-Tocilizumab 148375 Da) confirmed derivatization of the antibody. This represents 5 molecules of HYNIC per molecule of the antibody. Poliacrylamide gel electrophoresis confirmed that the antibody retained its integrity after derivatization. Radiochemical purity was 88±3 %. In vitro cell binding assays confirmed the binding ability of the radiolabeled antibody to IL-6 receptor. Specificity of binding was supported by competition experiments using unlabelled antibody. Confocal microscopy proved the ability of the fluorescent antibody to recognize the IL-6 receptor in U266 myeloma cells. Biodistribution at 24 h showed blood (8.0±2.0) %act/g, liver (11±1.5) %act/g, kidney (4.0±1.0)%act/g and spleen (6±1.4) %act/g uptake with hepatic and renal elimination. Animal models of MM are being evaluated using xenografted MM cells. Conclusion:99mTcHYNIC-Tocilizumab labeling was performed. The labeled antibody retained adequate biochemical and biological properties, which included maintenance of specific binding to IL-6 receptor. These findings indicate that this radiolabeled antibody could be used as an imaging agent in multiple myeloma. Acknowledgments:OIEA, Laboratorios Roche, Dr Gustavo Arroyo. Disclosures:No relevant conflicts of interest to declare.