Systemic Release Of Proinflammatory Cytokines Research Articles

Abstract 3185: Glatiramer acetate enhances tumor retention and mitigates systemic toxicity of toll-like receptor 9 agonists as intratumoral immunotherapy

Abstract Pathogen-associated molecular patterns (PAMP) are conserved molecular structures produced by microorganisms that are recognized as foreign by receptors of the innate immune system. Unmethylated cytosine-guanine oligodeoxynucleotides (CpG ODNs) are a storied drug class from the PAMP family that ligates Toll-like receptor 9 (TLR9). CpG ODNs have shown promising antitumor effects in preclinical studies by inducing potent pro-inflammatory immune responses. However, there are still practical challenges that have hindered clinical success, including inefficient in vivo delivery and severe immune-related toxicities caused by systemic exposure to CpG. We previously identified that glatiramer acetate (GA), an FDA-approved, lysine-rich polypeptide, could be applied as a cationic drug delivery vector for CpG delivery proximal to the injection site while mitigating systemic release of pro-inflammatory cytokines. To dive into the mechanism and evaluate pharmacological efficacy in more pathological models that simulate colorectal carcinoma, we validated the biodistribution of GA-CpG complexes (or R4B) and explored their safety and antitumor immunity in multiple mouse colorectal carcinoma models. In the CT26 single tumor model, intratumoral R4B treatment displayed comparable antitumoral efficacy as CpG treatment. Genome-wide transcriptome analysis showed that R4B treatment elicited much more prominent immune system response pathways in both lesions and spleens. The biodistribution study proved that R4B localized and gradually released CpG around the injection site while ‘naked’ CpG diffused away from the injection site quickly. In the CT26 dual tumor-bearing model, intratumoral administration of R4B generated systemic immune efficacy that led to an abscopal effect on distant untreated cancers, comparable to treatment with CpG alone. Notably, R4B treatment accomplished these effects with greatly mitigated systemic pro-inflammatory cytokines compared to CpG alone. These data help further elucidate the noncanonical role of glatiramer acetate to serve as a nucleic acid delivery scaffold that potentiates the safety of CpG adjuvant for cancer immunotherapy. Citation Format: Huan Gong, Daniel J. Griffin, Chad E. Groer, Xiaoqing Wu, Moustafa M. Abdelaziz, Sa Wu, Liang Xu, Laird M. Forrest, Cory J. Berkland. Glatiramer acetate enhances tumor retention and mitigates systemic toxicity of toll-like receptor 9 agonists as intratumoral immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3185.

Real-World Treatment Patterns and Outcomes in Patients with Hemophagocytic Lymphohistiocytosis (HLH) and Other Clinical Conditions Treated with Emapalumab: The Real-HLH Study Design

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening hyperinflammatory syndrome characterized by overactivation of the immune system due to systemic release of proinflammatory cytokines, especially of interferon gamma (IFNγ), and persistent activation of macrophages/histiocytes and T cells. Emapalumab, a fully human, anti-IFNγ monoclonal antibody that binds to both free and receptor-bound IFNy, neutralizing its biologic activity, was approved by the Food and Drug Administration (FDA) in 2018 for the treatment of adult and pediatric patients with primary HLH with refractory, recurrent or progressive disease or intolerance with conventional HLH therapy. The safety and efficacy of emapalumab was based on results from a pivotal phase 2/3 trial which reported a 63% overall response in patients treated with emapalumab. Since approval, no study has evaluated the use of emapalumab in a larger cohort of patients in the real-world clinical setting.Aim: To assess real-world treatment patterns and outcomes, clinical and demographic characteristics among patients treated with emapalumab.Method: This retrospective, non-interventional, observational medical chart review study will include patients treated across treatment centers in the US with emapalumab in a non-clinical trial setting. The study aims to include more than 100 patients who have been treated with at least one dose of emapalumab between November 20, 2018 and December 31, 2020 (patient identification period). The date that the patient initiates treatment with emapalumab within the patient identification period is defined as the index date. The post-index date is defined as the period from the index date through to the study end date (June 30, 2021), end of data availability for the patient, or date of death, whichever occurs first. Patients will be classified into three groups (i.e. primary HLH, secondary HLH, or non-HLH) based on the information obtained from their charts, the HLH 2004 diagnostic criteria, and adjudication by the REAL-HLH Steering Committee.Results: The primary objective of the study is to describe treatment patterns in patients with HLH treated with emapalumab in a real-world clinical setting, including emapalumab dose, treatment duration, and reasons for initiating or discontinuing treatment. The secondary objectives are to describe demographic and clinical characteristics of patients with HLH treated with emapalumab, and their outcomes. The exploratory objectives include detailing the demographic, clinical characteristics, treatment patterns, and outcomes of patients with non-HLH clinical conditions treated with emapalumab (Table 1). Demographics and clinical characteristics will be analyzed at the time of diagnosis. Treatment patterns and outcomes will be analyzed during the post-index date.Conclusion: The study aims to assess treatment patterns and outcomes, clinical and demographic characteristics among patients treated with emapalumab, a novel IFNγ blocking agent, in real-world clinical settings in the US. [Display omitted] DisclosuresAllen: Sobi: Consultancy. Leiding: Sobi: Consultancy. Chandrakasan: Sobi: Consultancy. Walkovich: X4 Pharmaceuticals: Other: Local PI for clinical trial involving mavorixafor and patients with neutropenia; Swedish Orphan Biovitrum AB (Sobi): Consultancy, Honoraria; Pharming: Honoraria, Membership on an entity's Board of Directors or advisory committees; Horizon Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees. Oladapo: Sobi: Current Employment. Yee: Sobi: Current Employment. Pednekar: Sobi: Consultancy; PRECISIONheor: Current Employment. Raza: Sobi: Consultancy; PRECISIONheor: Current Employment. Jordan: Sobi: Consultancy.

Autologous Placenta-derived Mesenchymal Stem Cell Transplantation for Labored Pregnant Patients With COVID-19

Coronavirus Disease 2019 (COVID-19) is one of the most critical health issues in the world. According to the findings, systemic proinflammatory cytokine release is associated with the pathogenesis of cytokine storm, contributing to morbidities and even mortality in patients diagnosed with COVID-19. Among pregnant patients diagnosed with COVID-19, preterm labor is one of the most crucial side effects, with a prevalence of up to 63.8% in some studies. As well as cytokine storm, proinflammatory cytokines are involved in preterm labor. Mesenchymal Stem Cells (MSCs) transplantation has been used in different trials to suppress inflammation in many inflammatory diseases. MSCs have also been successfully applied to treat patients diagnosed with COVID-19, considering the cytokine storm in these patients. So, it is possible to use the transplantation of MSCs derived from the maternal side of the placenta as an autologous product to suppress cytokine storm in critically ill patients diagnosed with COVID-19. The autologous transplantation of MSCs helps to suppress cytokine storm and systemic inflammation. Inhibition of systemic cytokine release could prevent poor outcomes, especially mortality and morbidities in the mentioned patients.

Macrophage polarization in obesity induced inflammation: The effect of HSP70

Abstract Obesity is a chronic inflammatory disease that plagues our nation’s healthcare system. Tissue macrophages and recruited monocytes are implicated in the systemic release of pro-inflammatory cytokines that foster disease progression. Diet-induced obesity (DIO) is prevented in heat shock protein 70 over-expressing (HSP70 transgenic; TG) mice. While there are several mechanisms responsible for this protective response, prevention of macrophage polarization to a pro-inflammatory phenotype (M1) may be one contributory mechanism that warrants further investigation. Using a TG mouse line with selective over-expression of HSP70 in villin-expressing epithelial cells, male TG and non-transgenic (NTG) littermates were fed a low fat (LF; 10 kcal% fat) or high fat (HF; 60 kcal% fat) diet for 13 weeks (Research Diets, Inc). Peritoneal cavity macrophages were harvested from these mice and analyzed by flow cytometry (Beckman Coulter Cytoflex) using the following markers: total (F4/80 APC), M1 (CD38 PE), and M2 (CD301 APC/Fire 750) macrophages. TG mice demonstrated increased F4/80+high macrophages and more F4/80+high M2 cells in comparison to their NTG littermates (p=0.051). These results demonstrate HSP70 over-expression in vivo increases the population of macrophages, particularly anti-inflammatory M2 macrophages, in the peritoneal cavity. Preferential M2 phenotype could be a significant contributory factor to HSP70-mediated protection from DIO.

Association of SARS-CoV-2 clades with clinical, inflammatory and virologic outcomes: An observational study

BackgroundHost determinants of severe coronavirus disease 2019 include advanced age, comorbidities and male sex. Virologic factors may also be important in determining clinical outcome and transmission rates, but limited patient-level data is available. MethodsWe conducted an observational cohort study at seven public hospitals in Singapore. Clinical and laboratory data were collected and compared between individuals infected with different SARS-CoV-2 clades. Firth's logistic regression was used to examine the association between SARS-CoV-2 clade and development of hypoxia, and quasi-Poisson regression to compare transmission rates. Plasma samples were tested for immune mediator levels and the kinetics of viral replication in cell culture were compared. Findings319 patients with PCR-confirmed SARS-CoV-2 infection had clinical and virologic data available for analysis. 29 (9%) were infected with clade S, 90 (28%) with clade L/V, 96 (30%) with clade G (containing D614G variant), and 104 (33%) with other clades ‘O’ were assigned to lineage B.6. After adjusting for age and other covariates, infections with clade S (adjusted odds ratio (aOR) 0·030 (95% confidence intervals (CI): 0·0002–0·29)) or clade O (B·6) (aOR 0·26 (95% CI 0·064–0·93)) were associated with lower odds of developing hypoxia requiring supplemental oxygen compared with clade L/V. Patients infected with clade L/V had more pronounced systemic inflammation with higher concentrations of pro-inflammatory cytokines, chemokines and growth factors. No significant difference in the severity of clade G infections was observed (aOR 0·95 (95% CI: 0·35–2·52). Though viral loads were significantly higher, there was no evidence of increased transmissibility of clade G, and replicative fitness in cell culture was similar for all clades. InterpretationInfection with clades L/V was associated with increased severity and more systemic release of pro-inflammatory cytokines. Infection with clade G was not associated with changes in severity, and despite higher viral loads there was no evidence of increased transmissibility.

'Geno-to-pheno' SARS-CoV-2 genome-COVID-19 association studies

'Geno-to-pheno' SARS-CoV-2 genome-COVID-19 association studies

Structural alterations and inflammation in the heart after multiple trauma followed by reamed versus non-reamed femoral nailing.

BackgroundApproximately 30,000 patients with blunt cardiac trauma are recorded each year in the United States. Blunt cardiac injuries after trauma are associated with a longer hospital stay and a poor overall outcome. Organ damage after trauma is linked to increased systemic release of pro-inflammatory cytokines and damage-associated molecular patterns. However, the interplay between polytrauma and local cardiac injury is unclear. Additionally, the impact of surgical intervention on this process is currently unknown. This study aimed to determine local cardiac immunological and structural alterations after multiple trauma. Furthermore, the impact of the chosen fracture stabilization strategy (reamed versus non-reamed femoral nailing) on cardiac alterations was studied.Experimental approach15 male pigs were either exposed to multiple trauma (blunt chest trauma, laparotomy, liver laceration, femur fracture and haemorrhagic shock) or sham conditions. Blood samples as well as cardiac tissue were analysed 4 h and 6 h after trauma. Additionally, murine HL-1 cells were exposed to a defined polytrauma-cocktail, mimicking the pro-inflammatory conditions after multiple trauma in vitro.ResultsAfter multiple trauma, cardiac structural changes were observed in the left ventricle. More specifically, alterations in the alpha-actinin and desmin protein expression were found. Cardiac structural alterations were accompanied by enhanced local nitrosative stress, increased local inflammation and elevated systemic levels of the high-mobility group box 1 protein. Furthermore, cardiac alterations were observed predominantly in pigs that were treated by non-reamed intramedullary reaming. The polytrauma-cocktail impaired the viability of HL-1 cells in vitro, which was accompanied by a release of troponin I and HFABP.DiscussionMultiple trauma induced cardiac structural alterations in vivo, which might contribute to the development of early myocardial damage (EMD). This study also revealed that reamed femoral nailing (reamed) is associated with more prominent immunological cardiac alterations compared to nailing without reaming (non-reamed). This suggests that the choice of the initial fracture treatment strategy might be crucial for the overall outcome as well as for any post-traumatic cardiac consequences.

Association of SARS-CoV-2 Clades with Clinical, Inflammatory and Virologic Outcomes: An Observational Study

Background: Host determinants of severe coronavirus disease 2019 include advanced age, comorbidities and male sex. Virologic factors may also be important in determining clinical outcome and transmission rates, but limited patient-level data is available. Methods: We conducted an observational cohort study at seven public hospitals in Singapore. Clinical and laboratory data were collected and compared between individuals infected with different SARS-CoV-2 clades. Firth’s logistic regression was used to examine the association between SARS-CoV-2 clade and development of hypoxia, and quasi-Poisson regression to compare transmission rates. Plasma samples were tested for immune mediator levels and the kinetics of viral replication in cell culture were compared. Findings: 319 patients with PCR-confirmed SARS-CoV-2 infection had clinical and virologic data available for analysis. 29 (9%) were infected with clade S, 90 (28%) with clade L/V, 96 (30%) with clade G (containing D614G variant), and 104 (33%) with other clades ‘O’ were assigned to lineage B.6. After adjusting for age and other covariates, infections with clade S (adjusted odds ratio (aOR) 0·030 (95% confidence intervals (CI): 0·0002-0·29)) or clade O (B·6) (aOR 0·26 (95% CI 0·064-0·93)) were associated with lower odds of developing hypoxia requiring supplemental oxygen compared with clade L/V. Patients infected with clade L/V had more pronounced systemic inflammation with higher concentrations of pro-inflammatory cytokines, chemokines and growth factors. No significant difference in the severity of clade G infections was observed (aOR 0·95 (95% CI: 0·35-2·52). Though viral loads were significantly higher, there was no evidence of increased transmissibility of clade G, and replicative fitness in cell culture was similar for all clades. Interpretation: Infection with clades L/V was associated with increased severity and more systemic release of pro-inflammatory cytokines. Infection with clade G was not associated with changes in severity, and despite higher viral loads there was no evidence of increased transmissibility.Funding Statement: This study was funded by grants from the Singapore National Medical Research Council (COVID19RF- 001, COVID19RF2-0001, COVID19RF-007, and COVID19RF-60) and Biomedical Research Council (project number H20/04/g1/006).Declaration of Interests: No conflicts of interest declared.Ethics Approval Statement: The epidemiological investigation was conducted under the Infectious Diseases Act (Singapore). Study protocols were approved by ethics committees of the National Healthcare Group and SingHealth. Written informed consent was obtained from participants for clinical data and biological sample collection as part of the PROTECT study (2012/00917; 2018/3045). A waiver of informed consent for retrospective data collection only was granted for individuals admitted to the National Centre of Infectious Diseases (2020/01122). Healthy donor samples were collected under study numbers 2017/2806 and NUS IRB 04-140.

Effective cancer immunotherapy in mice by polyIC-imiquimod complexes and engineered magnetic nanoparticles

Encouraging results are emerging from systems that exploit Toll like receptor (TLR) signaling, nanotechnology, checkpoint inhibition and molecular imaging for cancer immunotherapy. A major remaining challenge is developing effective, durable and tumour-specific immune responses without systemic toxicity. Here, we report a simple and versatile system based on synergistic activation of immune responses and direct cancer cell killing by combined TLR ligation using polyIC as TLR3 and imiquimod (R837) as TLR7 agonist, in combination with the model antigen ovalbumin (OVA) and phospholipid micelles loaded with zinc-doped iron oxide magnetic nanoparticles (MNPs). The combination of TLR agonists triggered a strong innate immune response in the lymph nodes (LNs) without systemic release of pro-inflammatory cytokines. The vaccines showed excellent efficacy against aggressive B16-F10 melanoma cells expressing OVA, which was improved with immune checkpoint abrogation of the immunosuppressive programmed death-ligand 1 (PD-L1) at the level of the cancer cells. By magnetic resonance (MR) and nuclear imaging we could track the vaccine migration from the site of injection to LNs and tumour. Overall, we show this synergistic TLR agonists and their combination with MNPs and immune checkpoint blockade to have considerable potential for preclinical and clinical development of vaccines for cancer immunotherapy.

Staphlyococcus aureus phenol-soluble modulins stimulate the release of proinflammatory cytokines from keratinocytes and are required for induction of skin inflammation.

Staphylococcus aureus is a human commensal that colonizes the skin. While it is normally innocuous, it has strong associations with atopic dermatitis pathogenesis and has become the leading cause of skin and soft tissue infections in the United States. The factors that dictate the role of S. aureus in disease are still being determined. In this work, we utilized primary keratinocyte culture and an epidermal murine colonization model to investigate the role of S. aureus phenol-soluble modulins (PSMs) in proinflammatory cytokine release and inflammation induction. We demonstrated that many species of Staphylococcus are capable of causing release of interleukin 18 (IL-18) from keratinocytes and that S. aureus PSMs are necessary and sufficient to stimulate IL-18 release from keratinocytes independently of caspase 1. Further, after 7 days of epicutaneous exposure to wild-type S. aureus, but not S. aureus Δpsm, we saw dramatic changes in gross pathology, as well as systemic release of proinflammatory cytokines. This work demonstrates the importance of PSM peptides in S. aureus-mediated inflammatory cytokine release from keratinocytes in vitro and in vivo and further implicates PSMs as important contributors to pathogenesis.

A potent and selective calcitonin gene-related peptide (CGRP) receptor antagonist, MK-8825, inhibits responses to nociceptive trigeminal activation: Role of CGRP in orofacial pain

Temporomandibular disorders (TMDs) are orofacial pains within the trigeminal distribution, which involve the masticatory musculature, the temporomandibular joint or both. Their pathophysiology remains unclear, as inflammatory mediators are thought to be involved, and clinically TMD presents pain and sometimes limitation of function, but often appears without gross indications of local inflammation, such as visible edema, redness and increase in temperature. Calcitonin gene-related peptide (CGRP) has been implicated in other pain disorders with trigeminal distribution, such as migraine, of which TMD shares a significant co-morbidity. CGRP causes activation and sensitization of trigeminal primary afferent neurons, independent of any inflammatory mechanisms, and thus may also be involved in TMD. Here we used a small molecule, selective CGRP receptor antagonist, MK-8825, to dissect the role of CGRP in inducing spontaneous nociceptive facial grooming behaviors, neuronal activation in the trigeminal nucleus, and systemic release of pro-inflammatory cytokines, in a mouse model of acute orofacial masseteric muscle pain that we have developed, as a surrogate of acute TMD. We show that CFA masseteric injection causes significant spontaneous orofacial pain behaviors, neuronal activation in the trigeminal nucleus, and release of interleukin-6 (IL-6). In mice pre-treated with MK-8825 there is a significant reduction in these spontaneous orofacial pain behaviors. Also, at 2 and 24h after CFA injection the level of Fos immunoreactivity in the trigeminal nucleus, used as a marker of neuronal activation, was much lower on both ipsilateral and contralateral sides after pre-treatment with MK-8825. There was no effect of MK-8825 on the release of IL-6. These data suggest that CGRP may be involved in TMD pathophysiology, but not via inflammatory mechanisms, at least in the acute stage. Furthermore, CGRP receptor antagonists may have therapeutic efficacy in the treatment of TMD, as they do with migraine.

Group A Streptococcus Modulates Host Inflammation by Manipulating Polymorphonuclear Leukocyte Cell Death Responses

Polymorphonuclear leukocyte (PMN) cell death strongly influences the resolution of inflammatory episodes, and may exacerbate adverse pathologies in response to infection. We investigated PMN cell death mechanisms following infection by virulent group A Streptococcus (GAS). Human PMNs were infected in vitro with a clinical, virulent GAS isolate and an avirulent derivative strain, and compared for phagocytosis, the production of reactive oxygen species (ROS), mitochondrial membrane depolarization and apoptotic markers. C57BL/6J mice were then infected, in order to observe the effects on murine PMNs in vivo. Human PMNs phagocytosed virulent GAS less efficiently, produced less ROS and underwent reduced mitochondrial membrane depolarization compared with phagocytosis of avirulent GAS. Morphological and biochemical analyses revealed that PMNs infected with avirulent GAS exhibited nuclear fragmentation and caspase-3 activation consistent with an anti-inflammatory apoptotic phenotype. Conversely, virulent GAS induced PMN vacuolization and plasma membrane permeabilization, leading to a necrotic form of cell death. Infection of the mice with virulent GAS engendered significantly higher systemic pro-inflammatory cytokine release and localized infiltration of murine PMNs, with cells associated with virulent GAS infection exhibiting reduced apoptotic potential. Avirulent GAS infection was associated with lower levels of proinflammatory cytokines and tissue PMN apoptosis. We propose that the differences in PMN cell death mechanisms influence the inflammatory responses to infection by GAS.

Psoriasis Epidemiology: The Interplay of Genes and the Environment

Psoriasis is a common chronic dermatological disease whose prevalence varies among different populations worldwide. In epidemiological studies, the factors that potentially account for this variability include climate, genetic susceptibility, and environmental antigen exposure. In this issue, Parisi et al. performed a systematic review to explore the global prevalence and incidence of psoriasis.

Engineering DNA Nanoparticles as Immunomodulatory Reagents that Activate Regulatory T Cells

Nanoparticles containing DNA complexed with the cationic polymer polyethylenimine are efficient vehicles to transduce DNA into cells and organisms. DNA/polyethylenimine nanoparticles (DNPs) also elicit rapid and systemic release of proinflammatory cytokines that promote antitumor immunity. In this study, we report that DNPs possess previously unrecognized immunomodulatory attributes due to rapid upregulation of IDO enzyme activity in lymphoid tissues of mice. IDO induction in response to DNP treatment caused dendritic cells and regulatory T cells (Tregs) to acquire potent regulatory phenotypes. As expected, DNP treatment stimulated rapid increase in serum levels of IFN type I (IFN-αβ) and II (IFN-γ), which are both potent IDO inducers. IDO-mediated Treg activation was dependent on IFN type I receptor signaling, whereas IFN-γ receptor signaling was not essential for this response. Moreover, systemic IFN-γ release was caused by TLR9-dependent activation of NK cells, whereas TLR9 signaling was not required for IFN-αβ release. Accordingly, DNPs lacking immunostimulatory TLR9 ligands in DNA stimulated IFN-αβ production, induced IDO, and promoted regulatory outcomes, but did not stimulate potentially toxic, systemic release of IFN-γ. DNP treatment to induce IDO and activate Tregs blocked Ag-specific T cell responses elicited in vivo following immunization and suppressed joint pathology in a model of immune-mediated arthritis. Thus, DNPs lacking TLR9 ligands may be safe and effective reagents to protect healthy tissues from immune-mediated destruction in clinical hyperimmune syndromes.

Serum Proinflammatory Cytokine Levels and White Blood Cell Differential Count in Patients with Different Degrees of Severity of Acute Alcoholic Pancreatitis

Several studies suggest that cytokines and neutrophils play an important role in the pathogenesis of acute pancreatitis (AP). The AIM OF THE STUDY was to assess the systemic release of proinflammatory cytokines and WBC (white blood cells) count with differential in patients with acute alcoholic pancreatitis (AAP) and to characterize the differences between patients with mild and severe forms of the disease. Thirty-five patients with the mild form of acute alcoholic pancreatitis (MAAP) were compared to 11 patients with severe acute alcoholic pancreatitis (SAAP). Serum levels of IL-6, IL-8, IL-12p40 and WBC differential count were measured every second day during the first week after admission. During the course of the study, the average level of IL-6 was significantly (p<0.05) higher in patients with SAAP than in patients with the mild form of the disease (MAAP). Serum levels of IL-8 and IL-12p40 on admission were higher in patients with SAAP than in patients with MAAP but the difference was not statistically significant. Of all the types of WBCs, neutrophils were significantly (p<0.05) elevated the entire time in SAAP patients when compared to patients with MAAP on 5th and 7th day from admission to hospital. Patients with SAAP had significantly higher proinflammatory cytokine IL-6 levels and neutrophil counts than patients with MAAP. The results suggest that proliferation and overstimulation of this subset of leukocytes might contribute to the development of the systemic inflammatory response in patients with SAAP.

Hepatocellular Necrosis, Apoptosis, and Proliferation after Transcatheter Arterial Embolization or Chemoembolization in a Standardized Rabbit Model

Purpose To evaluate the effect of transcatheter arterial chemoembolization versus transcatheter arterial embolization on hepatocellular damage, apoptosis, proliferation, and proinflammatory response in a rabbit VX2 tumor model. Materials and Methods Rabbits implanted with VX2 tumors in left liver lobes were randomly divided into three groups: a control group (n = 9) that underwent infusion of distilled water into the left hepatic artery, an embolization group (n = 15) that underwent left hepatic artery embolization with polyvinyl alcohol (PVA) particles, and a chemoembolization group (n = 15) that underwent left hepatic artery infusion of a mixture of 10-hydroxycamptothecin and iodized oil followed by PVA embolization. Serum and liver samples were collected at 6 hours, 3 days, and 7 days postoperatively. Liver damage was measured by liver function tests and histologic analysis. Ki-67 immunohistochemistry and terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling were performed to quantify proliferating and apoptotic cells. Serum tumor necrosis factor (TNF)–α levels were measured to assess proinflammatory response. Results Compared with embolization, chemoembolization caused liver injury with a greater increase in serum alanine aminotransferase and aspartate aminotransferase levels on days 3 and 7; histologic analysis showed increased hepatic necrosis in adjacent liver tissue beginning at day 3 and increased serum levels of TNF-α at 6 hours. By contrast, chemoembolization resulted in a slower increase in hepatocyte proliferation. Additionally, increased apoptotic hepatocytes were observed after embolization and chemoembolization. Conclusions In contrast to embolization, nonsuperselective transcatheter arterial chemoembolization increased hepatocellular damage and stimulated systemic proinflammatory cytokine release, but inhibited hepatocyte proliferation.

Intravenous Injection of Endogenous Microbial Components Abrogates DSS-Induced Colitis

The etiology of inflammatory bowel diseases (IBD) is largely unknown, but appears to be perpetuated by uncontrolled responses to antigenic components of the endogenous flora. Tolerance to antigenic stimulation can be achieved by exposure to a given antigen in high amounts (high dose tolerance). Colitis induced by feeding of Dextran Sodium Sulfate (DSS) is an often-used animal model mimicking clinical and histological features of human IBD. We investigated whether treatment with high doses of endogenous bacterial components can affect the response to these antigenic components and thus impact the course of the inflammatory response induced by DSS. 129/SvEv mice were injected intravenously in the tail vein with lysates prepared from fecal material of conventionally-raised mice. Control mice received a solution of bacterial antigen-free lysates prepared from fecal material of germ-free mice. Seven days later, colitis was induced in these mice by introducing DSS (3.5%) in the drinking water for 5 days. Onset and course of the inflammatory response was monitored by assessment of weight loss. Mice were sacrificed at day 7 post colitis induction and tested for histopathologic injury, intestinal cytokine release, and systemic response to bacterial antigens. Intravenous injection with fecal lysates reduced intestinal and antigen-stimulated systemic pro-inflammatory cytokine release and prevented DSS-induced weight loss and intestinal injury. Pretreatment with high amount of endogenous bacterial components has a profound tolerogenic effect on the systemic and mucosal immune responses resulting in reduced intestinal inflammation and abrogates colitis-induced weight loss.

Monocyte Deactivation Correlates With Injury Severity Score, But Not With Heme Oxygenase-1 Levels in Trauma Patients

Traumatic injury induces a local and systemic release of pro-inflammatory cytokines, acute phase proteins, hormones, and other inflammatory mediators. The excessive release of these mediators plays an important role in the pathogenesis of shock. In parallel to this pro-inflammatory response, there is a regulatory response characterized by the release of anti-inflammatory mediators, which is thought to represent the host's attempt to restore immunological equilibrium. Studies in septic patients have suggested the compensatory anti-inflammatory response may result in an "immunodeficient state" that leaves the host susceptible to further infectious insults. A key feature of the anti-inflammatory state in septic patients is a change in the responsiveness of monocytes that has been termed "monocyte deactivation." This is supported by data that link monocyte deactivation to increased mortality in septic patients. Monocytes with reduced HLA-DR expression have been described in trauma patients. We collected blood from 25 severely injured patients and evaluated peripheral blood mononuclear cells (PBMC) for HLA-DR expression and TNF-α response to LPS stimulation as markers of monocyte deactivation. Levels of intracellular HO-1 were determined in each patient, as HO-1 has been implicated in monocyte deactivation in patients with severe systemic inflammatory response syndrome (SIRS). HLA-DR expression correlated inversely with Injury Severity Scores and TNF-α response to LPS stimulation, but failed to correlate with HO-1 levels in these patients. HLA-DR expression was decreased in normal monocytes stimulated with patient plasma, but this treatment had no effect on HO-1 levels. These results suggest monocyte deactivation in trauma patients is unlikely to be mediated by HO-1.

Ischemic Postconditioning Attenuates Lung Reperfusion Injury and Reduces Systemic Proinflammatory Cytokine Release Via Heme Oxygenase 1

Systemic inflammatory response following ischemia-reperfusion injury (IRI) to a specific organ may cause injuries in multiple remote organs. The emergence of ischemic postconditioning (IPO) provides a potential method for experimentally and clinically attenuating various types of organ postischemic injuries. We have shown that IPO can attenuate lung IRI by up-regulating the protein expression of heme oxygenase-1(HO-1). This study tested the hypothesis that IPO attenuates systemic inflammatory responses following lung IRI by activating HO-1. Anaesthetized and mechanically ventilated adult Sprague-Dawley rats were randomly assigned to one of the following groups (n = 8 each): the sham-operated control group, the ischemia-reperfusion (IR) group (40 min of left-lung ischemia and 120 min of reperfusion), the IPO group (three successive cycles of 30-s reperfusion per 30-s occlusion before restoring full perfusion), and the zinc protoporphyrin IX (ZnP) plus IPO group (ZnP, an inhibitor of HO-1, was injected intraperitoneally at 20 mg/kg 24 h prior to the experiment, and the rest of the procedures were similar to that of the IPO group). Lung injury was assessed by arterial blood gas analysis, wet-to-dry lung weight ratio and tissue histologic and biochemical changes. The lung tissue and plasma levels of lipid peroxidation were determined by measuring the contents of malondialdehyde (MDA) production. Protein expression of HO-1 was determined by Western blotting. Pulmonary neutrophil was counted. Lung tissue myeloperoxidase (MPO) activity as well as plasma levels of proinflammatory cytokines tumor necrosis factor-α (TNF-α), interleukines 6 and 8 (IL-6, IL-8) were determined by spectrophotography. Lung ischemia-reperfusion led to severe lung pathologic morphologic changes and increased pulmonary MDA production, neutrophil count, and MPO activity and reduced arterial oxygen partial pressure (all P < 0.05 IR versus sham), accompanied with a compensatory increase in HO-1 protein and activity. Plasma levels of TNF-α, IL-6, and IL-8 were increased in the IR group (all P < 0.05 versus sham). IPO attenuated or prevented all the above changes, except that it further increased lung HO-1 activity. Treatment with ZnP abolished all the protective effects of postconditioning. Postconditioning attenuated pulmonary neutrophil accumulation and activation and lung IRI and reduced systemic inflammatory responses by activating HO-1.

Peroxisome Proliferator-Activated Receptor δ Regulates Inflammation via NF-κB Signaling in Polymicrobial Sepsis

The nuclear peroxisome proliferator-activated receptor δ (PPARδ) is an important regulator of lipid metabolism. In contrast to its known effects on energy homeostasis, its biological role on inflammation is not well understood. We investigated the role of PPARδ in the modulation of the nuclear factor-κB (NF-κB)-driven inflammatory response to polymicrobial sepsis in vivo and in macrophages in vitro. We demonstrated that administration of GW0742, a specific PPARδ ligand, provided beneficial effects to rats subjected to cecal ligation and puncture, as shown by reduced systemic release of pro-inflammatory cytokines and neutrophil infiltration in lung, liver, and cecum, when compared with vehicle treatment. Molecular analysis revealed that treatment with GW0742 reduced NF-κB binding to DNA in lung and liver. In parallel experiments, heterozygous PPARδ-deficient mice suffered exaggerated lethality when subjected to cecal ligation and puncture and exhibited severe lung injury and higher levels of circulating tumor necrosis factor-α (TNFα) and keratinocyte-derived chemokine than wild-type mice. Furthermore, in lipopolysaccharide-stimulated J774.A1 macrophages, GW0742 reduced TNFα production by inhibiting NF-κB activation. RNA silencing of PPARδ abrogated the inhibitory effects of GW0742 on TNFα production. Chromatin immunoprecipitation assays revealed that PPARδ displaced the NF-κB p65 subunit from the κB elements of the TNFα promoter, while recruiting the co-repressor BCL6. These data suggest that PPARδ is a crucial anti-inflammatory regulator, providing a basis for novel sepsis therapies.