Local Acute Inflammatory Response Research Articles

Phytotherapeutic potential of compounds identified from fractionated extracts of Morus alba L., as an inhibitor of interleukin-6 in the treatment of rheumatoid arthritis: computational approach

The presence of HLA-DRB1 alleles that encode critical points associated with environmental interactions is associated with increased risk of rheumatoid arthritis caused by anti-citrullinated protein antibodies. Therefore, interleukin-6 (IL-6), a multifunctional cytokine that controls both local and systemic acute inflammatory responses through its ability to induce a phase response, plays a serious role. Its overexpression leads to pathological challenges such as rheumatoid arthritis and menopausal osteoporosis. However, targeting the IL-6 receptor and its region could be the major step in controlling the overexpression of this cytokine for therapeutic importance. Therefore, our research explored the computational insight needed to investigate the anti-RFA potential of phytochemicals from fractionated extracts of Morus alba L. against receptors, which have been implicated as druggable targets for the treatment of rheumatoid arthritis. In this study, fifty-nine (59) previously isolated and characterized phytochemicals from M. alba L. were identified from the literature and retrieved from the PubChem database. In silico screening was used to assess the mode of action of these phytochemicals from M. alba L. against receptors that may serve as therapeutic targets for rheumatoid arthritis. Molecular docking studies, toxicity prediction, drug visualization and molecular dynamics simulation (MD) of the ligands together with the receptor-identified target were carried out using the Schrodinger Molecular Drug Discovery Suite. The findings indicated that a selected group of ligands displayed significant binding strength to specific amino acid residues, revealing an important link between the building blocks of proteins (amino acids) and ligands at the inhibitor binding site through traditional chemical interactions, such as interactions between hydrophobic and hydrogen bonds. The binding affinities of the receptors were carefully checked via comparison with those of the approved ligands, and the results suggested structural and functional changes in the lead compounds. Therefore, the bioactive component from M. alba L. could be a lead foot interleukin-6 (IL-6) inhibitor and could be a promising lead compound for the treatment of rheumatoid arthritis and related challenges. Communicated by Ramaswamy H. Sarma

The Immuno-Suppressive Effects of Cyclic, Environmental Heat Stress in Broiler Chickens: Local and Systemic Inflammatory Responses to an Intradermal Injection of Lipopolysaccharide.

To assess effects of environmental heat stress (HS) on the local and systemic inflammatory responses to lipopolysaccharide (LPS), broilers were reared under thermoneutral (TN) or cyclic HS conditions. Thermoneutral temperatures followed commercial production settings, with HS broilers exposed to 35 °C for 14 h/day from 4 days onward. At 37 days, HS- and TN-broilers were assigned to either LPS (100 μg/mL) or endotoxin-free phosphate-buffered saline (PBS; vehicle) treatments, eight each to HS- and TN-LPS, four each to HS- and TN-PBS. Treatments were administered by intradermal injection of growing feather (GF) pulps; 10 μL/GF; 12 GF/broiler. Blood and GF were collected before and at 6 and 24 h post-injection to assess leukocyte population changes in GF-pulps and blood, reactive oxygen species (ROS) generation and cytokine expression in GF-pulps, and plasma concentrations of alpha-1 acid glycoprotein (AGP-1). HS-LPS broilers had lower (p ≤ 0.05) infiltration of heterophils and macrophages, ROS generation, and inflammatory cytokine expression in GF-pulps, and lacked the increases in heterophil, monocyte, and plasma AGP-1 concentrations observed in TN-LPS broilers. HS-broilers had similar or greater drops in blood lymphocytes 6 h post-LPS or -PBS injection, respectively, and lower baseline levels (p ≤ 0.05) of circulating T- and B-lymphocytes than TN-broilers. Results indicated that cyclic HS reduced the local and systemic acute inflammatory responses to LPS in broilers, likely impairing their innate defense against microbial infection.

EXPERIMENTAL SUBSTANTIATION OF THE USE OF XENOGENIC CEREBROSPINAL FLUID IN HERNIOLOGY TO REDUCE THE PERIPROSTHETIC REACTION

The aim of this study was to experimentally validate the possibility and advisability of the treatment of polypropylene mesh implants with xenogenic cerebrospinal fluid in order to reduce a local acute inflammatory response. An experimental evaluation of the effectiveness of the proprietary method of polypropylene mesh implant processing during their implantation in the tissues of the anterior abdominal wall (Patent of Ukraine No. 146637) is presented. It has been proven that the use of the proposed new technology for the treatment of polypropylene mesh implants with a biocompatible component is a simple, safe and effective method that optimizes the reparative processes in the peri-implant zone without affecting the mechanical properties of mesh implants. All of the treatment effects were found to increase the biocompatibility and improve the survival rate of mesh implants. The thickness of the inflammatory ridge around the elements of mesh implants significantly decreased on average by 35.3% when xenogenic cerebrospinal fluid was used.

Gene Expression Profiling of Classically Activated Macrophages in Leishmania infantum Infection: Response to Metabolic Pre-Stimulus with Itaconic Acid.

Leishmania infection of phagocytic cells, such as macrophages, induces the differentiation of infected cells into different phenotypes according to their surrounding microenvironments. The classical activation of macrophages involves metabolic reprogramming, in which several metabolites such as succinate, fumarate and itaconate are accumulated. The immunoregulatory functions of itaconate in the context of Leishmania infection were investigated in this paper. Ex vivo bone marrow-derived macrophages were differentiated into classically activated macrophages through IFNG activation and infection with Leishmania infantum. A high-throughput real-time qPCR experiment was designed for the analyses of 223 genes involved in immune response and metabolism. The transcriptional profile of classically activated macrophages revealed the enrichment of the IFNG response pathways and the upregulation of genes such as Cxcl9, Irf1, Acod1, Il12b, Il12rb1, Nos2 or Stat1. In vitro pre-stimulation with itaconate induced a loss of the parasite control and the upregulation of genes related to local acute inflammatory response. Our results reveal that itaconate accumulation dampened classically activated macrophage antiparasitic activity, and this is reflected by the differential expression of the Il12b, Icosl and Mki67 genes. The possibility of inducing parasite-killing responses in the host through metabolic reprograming is an interesting approach for the treatment of Leishmania infections that will undoubtedly attract increasing attention in the coming years.

Burn-injured skin is marked by a prolonged local acute inflammatory response of innate immune cells and pro-inflammatory cytokines.

The systemic and local immune response in burn patients is often extreme and derailed. As excessive inflammation can damage healthy tissues and slow down the healing process, modulation of inflammatory responses could limit complications and improve recovery. Due to its complexity, more detailed information on the immune effects of thermal injury is needed to improve patient outcomes. We therefore characterized and quantified subsets of immune cells and mediators present in human burn wound tissue (eschar), sampled at various time points. This study shows that after burn injury, the number of immune cells were persistently increased, unlike the normal wound healing process. There was an immediate, strong increase in neutrophils and a moderate increase in monocytes/macrophages and lymphocytes, especially in the second and third week post burn. The percentage of classical (CD14highCD16-) monocytes/macrophages demonstrated a steady decrease over time, whereas the proportion of intermediate (CD14highCD16+) monocytes/macrophages slowly increased. The absolute numbers of T cells, NK cells and B cells increased up to week 3, while the fraction of γδ T cells was increased only in week 1. Secretome profiling revealed high levels of chemokines and an overall pro-inflammatory cytokine milieu in burn tissue. The local burn immune response shows similarities to the systemic immune reaction, but differs in neutrophil maturity and lymphocyte composition. Altogether, the neutrophil surges, high levels of pro-inflammatory cytokines and limited immunosuppression might be key factors that prolong the inflammation phase and delay the wound healing process in burns.

Photodynamic therapy – significance in oncology

Photodynamic therapy (PDT) is one of the least toxic methods causing the death of cancer cells. Photosensitizer (PS) applied to a patient accumulates in the tumor, where under the appropriate wavelength and insensitivity of light is activated. Activated PS in the presence of oxygen produces reactive oxygen species (ROS), which make significant damage leading to the destruction of cancer cells by apoptosis, necrosis or autophagic process. Moreover, PDT causes an acute local inflammatory response that is involved in removing dead cells, restoring normal tissue homeostasis, and sometimes leads to the development of systemic immunity. However, some cells may survive treatment and develop resistance. Mechanisms, which lead to decrease of the level of PS in cells may be involved in the cytoprotection of cancer cells from PDT. Furthermore, increased activity of antioxidant mechanisms, overexpression of molecular chaperones and activation of survival pathways can protect cells from PDT.

Primary pituitary gland abscess in a 13-year-old girl. A clinical case description

A primary abscess in the region of the Sella turcica is a rare neurosurgical pathology especially in the pediatric population. This pathology has no specific symptoms and may have an atypical presentation. It has no specific radiological features making diagnosis very difficult. In this article, we report on a 13-year-old girl with a confirmed primary pituitary abscess. Clinical and instrumental investigations as well as hormonal profile indicated a lesion of the Rathkes pouch- like a craniopharyngioma and to a lesser extent, a pituitary adenoma. In this case, laboratory and Magnetic resonance studies did not show any features of systemic or local acute inflammatory response respectively. The child underwent a surgery, during which the diagnosis was made — primary abscess of the pituitary gland.

Chemical profiling of Callicarpa nudiflora and its effective compounds identification by compound-target network analysis

Callicarpa nudiflora, belonging to the family Verbenaceae, is widely used to treat inflammation caused by bacterial infection.However, the underlying active substances of C. nudiflora against inflammation remains obscure. In this work, an ultra high-performance liquid chromatography (UHPLC) coupled with quadrupole time-of-flight mass spectrometry method was developed to characterize the ingredients in C. nudiflora, and a validated UHPLC coupled with triple quadrupole tandem mass spectrometry method was applied to quantify major components. As a result, a total of 96 chemical compounds were identified in C. nudiflora, and 26 compounds of them were further quantified in 34 batches of C. nudiflora. Based on the identified components from C. nudiflora, a compound-target network for the anti-inflammation effect was constructed by reverse docking target prediction, disease associated genes screening in DisGeNET and the protein-protein interaction from STRING. The compound-target network showed that C. nudiflora might exert anti-inflammation effect on the target of complement 3 and 5 in the pathway of cells and molecules involved in local acute inflammatory response, and 16 effective candidate compounds were found such as catalpol, acteoside, rutin, etc. This study provided an opportunity to deepen the understanding of the chemical composition and the potential anti-inflammatory mechanism of C. nudiflora.

5-Aminolevulinic acid photodynamic therapy with and without Er:YAG laser for actinic keratosis: Changes in immune infiltration.

Ultraviolet light induced DNA damage, combined with immunosuppression and inflammation are involved in the pathogenesis of actinic keratosis. Photodynamic therapy not only destroys dysplastic cells via tissue destruction and vascular shutdown, but also induces an acute local inflammatory response and activates both the innate and adaptive immune system. In our current work we aimed to compare immunohistochemistry features of inflammatory infiltrate of actinic keratoses after 5-aminolevulinic acid photodynamic therapy with or without Er:YAG laser resurfacing. Eleven patients with multiple actinic keratosis on the scalp, face, hands or forearms were treated by conventional and Er:YAG laser assisted 5-aminolevulinic acid PDT in split-site manner. Biopsies of AKs were taken before, 48 h and 3 months after the treatment. CD3, CD4, CD8, CD1a, Ki67 and p53 expressions were analyzed by immunohistochemical methods. The number of p53 and Ki67 positive cells decreased significantly 3 months after treatment, but the abnormal cells were not eliminated totally. The number of CD1a+ Langerhans cells significantly decreased 48 h after both treatments, while CD8+ T cell count was significantly lower 3 months after Er:YAG laser assisted photodynamic therapy. However, the number of CD3+ and CD4+ T cells were not changed significantly 48 h and 3 months later. One session of 5-aminolevulinic acid photodynamic therapy even with Er:YAG laser pretreatment could not terminate actinic damage totally. Photodynamic therapy induced immunological changes. However further investigations are needed to answer how the composition of actinic keratosis' immune infiltrate influence the effect of photodynamic therapy.

Intradermal Application of Crotamine Induces Inflammatory and Immunological Changes In Vivo.

Crotamine is a single-chain polypeptide with cell-penetrating properties, which is considered a promising molecule for clinical use. Nevertheless, its biosafety data are still scarce. Herein, we assessed the in vivo proinflammatory properties of crotamine, including its local effect and systemic serum parameters. Sixty male Wistar rats were intradermically injected with 200, 400 and 800 µg crotamine and analyzed after 1, 3 and 7 days. Local effect of crotamine was assessed by determination of MPO and NAG activities, NO levels and angiogenesis. Systemic inflammatory response was assessed by determination of IL-10, TNF-α, CRP, NO, TBARS and SH groups. Crotamine induced macrophages and neutrophils chemotaxis as evidenced by the upregulation of both NAG (0.5–0.6 OD/mg) and MPO (0.1–0.2 OD/mg) activities, on the first and third day of analysis, respectively. High levels of NO were observed for all concentrations and time-points. Moreover, 800 μg crotamine resulted in serum NO (64.7 μM) and local tissue NO (58.5 μM) levels higher or equivalent to those recorded for their respective histamine controls (55.7 μM and 59.0 μM). Crotamine also induced a significant angiogenic response compared to histamine. Systemically, crotamine induced a progressive increase in serum CRP levels up to the third day of analysis (22.4–45.8 mg/mL), which was significantly greater than control values. Crotamine (400 μg) also caused an increase in serum TNF-α, in the first day of analysis (1095.4 pg/mL), however a significant increase in IL-10 (122.2 pg/mL) was also recorded for the same time-point, suggesting the induction of an anti-inflammatory effect. Finally, crotamine changed the systemic redox state by inducing gradual increase in serum levels of TBARS (1.0–1.8 μM/mL) and decrease in SH levels (124.7–19.5 μM/mL) throughout the experimental period of analysis. In summary, rats intradermally injected with crotamine presented local and systemic acute inflammatory responses similarly to histamine, which limits crotamine therapeutic use on its original form.

Immunological effects of photodynamic therapy in the treatment of actinic keratosis and squamous cell carcinoma.

The use of photodynamic therapy is extensive, due to its antitumoral, antibacterial and photorejuvenation effects. It destroys tumor via direct cell destruction and indirectly via vascular shutdown, induction of acute local inflammatory response and activation of the immune system. Both innate and adaptive immune cells are involved in the immunological effects of photodynamic therapy. In addition to UV-induced DNA damage, inflammation and immunosuppression are also essential elements in the pathogenesis of actinic keratosis. Both immunosuppression induced by UV and defective immune response to dysplastic keratinocytes may be the target of photodynamic therapy to eliminate actinic keratosis. These elements are discussed in the present review, highlighting the possible mechanism of photodynamic therapy to effectively treat actinic keratosis.

Mediation of the single-walled carbon nanotubes induced pulmonary fibrogenic response by osteopontin and TGF-β1

ABSTRACTPurpose of the study: A number of in vivo studies have shown that pulmonary exposure to carbon nanotubes (CNTs) may lead to an acute local inflammatory response, pulmonary fibrosis, and granulomatous lesions. Among the factors that play direct roles in initiation and progression of fibrotic processes are epithelial-mesenchymal transition and myofibroblasts recruitment/differentiation, both mediated by transforming growth factor-β1 (TGF-β1). Yet, other contributors to TGF-β1 associated signaling, such as osteopontin (OPN) has not been fully investigated. Materials and Methods: OPN-knockout female mice (OPN-KO) along with their wild-type (WT) counterparts were exposed to single-walled carbon nanotubes (SWCNT) (40 µg/mouse) via pharyngeal aspiration and fibrotic response was assessed 1, 7, and 28 days post-exposure. Simultaneously, RAW 264.7 and MLE-15 cells were treated with SWCNT (24 hours, 6 µg/cm2 to 48 µg/cm2) or bleomycin (0.1 µg/ml) in the presence of OPN-blocking antibody or isotype control, and TGF-β1 was measured in supernatants. Results and Conclusions: Diminished lactate dehydrogenase activity at all time points, along with less pronounced neutrophil influx 24 h post-exposure, were measured in broncho-alveolar lavage (BAL) of OPN-KO mice compared to WT. Pro-inflammatory cytokine release (IL-6, TNF-α, MCP-1) was reduced. A significant two-fold increase of TGF-β1 was found in BAL of WT mice at 7 days, while TGF-β1 levels in OPN-KO animals remained unaltered. Histological examination revealed marked decrease in granuloma formation and less collagen deposition in the lungs of OPN-KO mice compared to WT. RAW 264.7 but not MLE-15 cells exposed to SWCNT and bleomycin had significantly less TGF-β1 released in the presence of OPN-blocking antibody. We believe that OPN is important in initiating the cellular mechanisms that produce an overall pathological response to SWCNT and it may act upstream of TGF-β1. Further investigation to understand the mechanistic details of such interactions is critical to predict outcomes of pulmonary exposure to CNT.

Impact of serum as a dispersion agent for in vitro and in vivo toxicological assessments of TiO2 nanoparticles

Nanoparticles (NP) have a tendency to agglomerate after dispersion in physiological media, which can be prevented by the addition of serum. This may however result in modification of the toxic potential of particles due to the formation of protein corona. Our study aimed to analyze the role of serum that is added to improve the dispersion of 10nm TiO2 NPs on in vitro and in vivo effects following the exposure via the respiratory route. We characterized NP size, surface charge, sedimentation rate, the presence of protein corona and the oxidant-generating capacity after NP dispersion in the presence/absence of serum. The effect of serum on NP internalization, cytotoxicity and pro-inflammatory responses was assessed in a human pulmonary cell line, NCI-H292. Serum in the dispersion medium led to a slower sedimentation, but an enhanced cellular uptake of TiO2 NPs. Despite this greater uptake, the pro-inflammatory response in NCI-H292 cells was lower after serum supplementation (used either as a dispersant or as a cell culture additive), which may be due to a reduced intrinsic oxidative potential of TiO2 NPs. Interestingly, serum could be added 2h after the NP treatment without affecting the pro-inflammatory response. We also determined the acute pulmonary and hepatic toxicity in vivo 24h after intratracheal instillation of TiO2 NPs in C57BL/6N mice. The use of serum resulted in an underestimation of the local acute inflammatory response in the lung, while a systemic response on glutathione reduction remained unaffected. In conclusion, serum as a dispersion agent for TiO2 NPs can lead to an underestimation of the acute pro-inflammatory response in vitro and in vivo. To avoid potential unwanted effects of dispersants and medium components, we recommend that the protocol of NM preparation should be thoroughly tested, and reflect as close as possible realistic exposure conditions.

The White-Nose Syndrome Transcriptome: Activation of Anti-fungal Host Responses in Wing Tissue of Hibernating Little Brown Myotis.

White-nose syndrome (WNS) in North American bats is caused by an invasive cutaneous infection by the psychrophilic fungus Pseudogymnoascus destructans (Pd). We compared transcriptome-wide changes in gene expression using RNA-Seq on wing skin tissue from hibernating little brown myotis (Myotis lucifugus) with WNS to bats without Pd exposure. We found that WNS caused significant changes in gene expression in hibernating bats including pathways involved in inflammation, wound healing, and metabolism. Local acute inflammatory responses were initiated by fungal invasion. Gene expression was increased for inflammatory cytokines, including interleukins (IL) IL-1β, IL-6, IL-17C, IL-20, IL-23A, IL-24, and G-CSF and chemokines, such as Ccl2 and Ccl20. This pattern of gene expression changes demonstrates that WNS is accompanied by an innate anti-fungal host response similar to that caused by cutaneous Candida albicans infections. However, despite the apparent production of appropriate chemokines, immune cells such as neutrophils and T cells do not appear to be recruited. We observed upregulation of acute inflammatory genes, including prostaglandin G/H synthase 2 (cyclooxygenase-2), that generate eicosanoids and other nociception mediators. We also observed differences in Pd gene expression that suggest host-pathogen interactions that might determine WNS progression. We identified several classes of potential virulence factors that are expressed in Pd during WNS, including secreted proteases that may mediate tissue invasion. These results demonstrate that hibernation does not prevent a local inflammatory response to Pd infection but that recruitment of leukocytes to the site of infection does not occur. The putative virulence factors may provide novel targets for treatment or prevention of WNS. These observations support a dual role for inflammation during WNS; inflammatory responses provide protection but excessive inflammation may contribute to mortality, either by affecting torpor behavior or causing damage upon emergence in the spring.

Perivascular mast cells regulate vein graft neointimal formation and remodeling.

Objective. Emerging evidence suggests an important role for mast cells in vein graft failure. This study addressed the hypothesis that perivascular mast cells regulate in situ vascular inflammatory and proliferative responses and subsequent vein graft neointimal lesion formation, using an optimized local mast cell reconstitution method.Methods and Results. Neointimal hyperplasia was induced by insertion of a vein graft into the right carotid artery in wild type and mast cell deficient KitW−sh/W−sh mice. In some experiments, mast cells were reconstituted systemically (tail vein injection of bone marrow-derived mast cells) or locally (directly into the right neck area) prior to vein grafting. Vein graft neointimal lesion formation was significantly (P < 0.05) reduced in KitW−sh/W−sh mice. Mast cell deficiency reduced the number of proliferating cells, and inhibited L-selectin, CCL2, M-CSF and MIP-3α expression in the vein grafts. Local but not systemic mast cell reconstitution restored a perivascular mast cell population that subsequently promoted neointimal formation in mast cell deficient mice.Conclusion. Our data demonstrate that perivascular mast cells play a key role in promoting neointima formation by inducing local acute inflammatory and proliferative responses. These results suggest that ex vivo intraoperative targeting of mast cells may have therapeutic potential for the prevention of pathological vein graft remodeling.

Immunological aspects of antitumor photodynamic therapy outcome.

Photodynamic therapy (PDT) of cancer is an efficient and promising therapeutic modality approved for the treatment of several types of tumors and non-malignant diseases. It involves administration of a non-toxic photosensitizer followed by illumination of the tumor site with a harmless visible light. A light activated photosensitizer can transfer its energy directly to molecular oxygen, leading to production of highly toxic reactive oxygen species (ROS). Antitumor effects of PDT result from the combination of three independent mechanisms involving direct cytotoxicity to tumor cells, destruction of tumor vasculature and induction of the acute local inflammatory response. PDT-mediated inflammatory reaction is accompanied by tumor infiltration of the leukocytes, enhanced production of pro-inflammatory factors and cytokines. Photodynamic therapy is able to effectively stimulate both the innate and the adaptive arm of the immune system. In consequence, this regimen can lead to development of systemic and specific antitumor immune response. However, there are limited studies suggesting that under some specific circumstances, PDT on its own may exert some immunosuppressive effects leading to activation of immunosuppressive cells or cytokines production. In this report we briefly review all immunological aspects of PDT treatment.

Locally Injected Dexmedetomidine Inhibits Carrageenin-Induced Inflammatory Responses in the Injected Region

Dexmedetomidine, a highly selective agonist of α2-adrenoceptors, is a commonly used sedative; however, a potent anti-inflammatory effect has also been found. In the present study we evaluated the inhibitory effect of locally injected dexmedetomidine on inflammatory responses in the injected region. Local inflammation was induced in the hindpaws of male mice (aged 6-8 weeks) by intraplantar injection of lambda-carrageenin. To offset the central effect of tested agents, different agents were blindly injected into the left and right paws in the pairs of comparison. The effect of dexmedetomidine on edema (increase in paw volume), the accumulation of leukocytes, and production of tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2) were evaluated after carrageenin injection, using water displacement plethysmometry, histological imaging, immunohistochemistry, and Western blotting analysis. Furthermore, we also evaluated the effect of yohimbine, a full antagonist of α2-adrenoceptors, and phenylephrine, an agonist of the α1-adrenoceptor, on dexmedetomidine's action on inflammatory responses. Paw volume and amount of leukocytes in the injected region significantly increased after the injection of carrageenin. Similarly, TNF-α and COX-2 production was found in the subcutaneous region injected with carrageenin, 4 hours after injection. Dexmedetomidine significantly inhibited all increases in paw volume, leukocytes, and production of TNF-α and COX-2. Furthermore, yohimbine significantly antagonized the anti-inflammatory effects of dexmedetomidine, whereas phenylephrine did not significantly alter them. The findings suggest that locally injected dexmedetomidine exhibits an anti-inflammatory effect against local acute inflammatory responses, mediated by α2-adrenoceptors.

Targeting pro-inflammatory cytokines following joint injury: acute intra-articular inhibition of interleukin-1 following knee injury prevents post-traumatic arthritis.

IntroductionPost-traumatic arthritis (PTA) is a progressive, degenerative response to joint injury, such as articular fracture. The pro-inflammatory cytokines, interleukin 1(IL-1) and tumor necrosis factor alpha (TNF-α), are acutely elevated following joint injury and remain elevated for prolonged periods post-injury. To investigate the role of local and systemic inflammation in the development of post-traumatic arthritis, we targeted both the initial acute local inflammatory response and a prolonged 4 week systemic inflammatory response by inhibiting IL-1 or TNF-α following articular fracture in the mouse knee.MethodsAnti-cytokine agents, IL-1 receptor antagonist (IL-1Ra) or soluble TNF receptor II (sTNFRII), were administered either locally via an acute intra-articular injection or systemically for a prolonged 4 week period following articular fracture of the knee in C57BL/6 mice. The severity of arthritis was then assessed at 8 weeks post-injury in joint tissues via histology and micro computed tomography, and systemic and local biomarkers were assessed in serum and synovial fluid.ResultsIntra-articular inhibition of IL-1 significantly reduced cartilage degeneration, synovial inflammation, and did not alter bone morphology following articular fracture. However, systemic inhibition of IL-1, and local or systemic inhibition of TNF provided no benefit or conversely led to increased arthritic changes in the joint tissues.ConclusionThese results show that intra-articular IL-1, rather than TNF-α, plays a critical role in the acute inflammatory phase of joint injury and can be inhibited locally to reduce post-traumatic arthritis following a closed articular fracture. Targeted local inhibition of IL-1 following joint injury may represent a novel treatment option for PTA.

Dynamics of acute local inflammatory response after autologous transplantation of muscle-derived cells into the skeletal muscle.

The vast majority of myoblasts transplanted into the skeletal muscle die within the first week after injection. Inflammatory response to the intramuscular cell transfer was studied in allogeneic but not in autologous model. The aim of this study was to evaluate immune reaction to autotransplantation of myogenic cells and to assess its dynamics within the first week after injection. Muscle-derived cells or medium alone was injected into the intact skeletal muscles in autologous model. Tissue samples were collected 1, 3, and 7 days after the procedure. Our analysis revealed the peak increase of the gene expression of all evaluated cytokines (Il-1α, Il-1 β, Il-6, Tgf-β, and Tnf-α) at day 1. The mRNA level of analyzed cytokines normalized in subsequent time points. The increase of Il- β gene expression was further confirmed at the protein level. Analysis of the tissue sections revealed rapid infiltration of injected cell clusters with neutrophils and macrophages. The inflammatory infiltration was almost completely resolved at day 7. The survived cells were able to participate in the muscle regeneration process. Presented results demonstrate that autotransplanted muscle-derived cells induce classical early immune reaction in the site of injection which may contribute to cellular graft elimination.

Toll‐like receptor 4 signaling regulates the acute local inflammatory response to injury and the fibrosis/neovascularization of sterile wounds

The role of Toll-like receptor 4 (TLR4) in the regulation of inflammation and fibrosis in sterile wounds was investigated in TLR4 signal-deficient (C3H/HeJ or TLR4(-/-) ) and control mice using the subcutaneously implanted polyvinyl alcohol sponge wound model. Total and differential wound cell counts 1, 3, and 7 days after injury did not differ between C3H/HeJ and C3H/HeOuJ animals. Blood monocytes from both strains expressed CCR2 equally. Day one wounds in C3H/HeJ mice contained fewer Gr-1(high) wound macrophages, CCL3, and CCL5, and more CCL17 than those in controls. The accumulation of CCL2, CX3CL1, tumor necrosis factor-α, interleukin (IL)-6, IL-10, IL-12, and interferon-γ in wound fluids was not TLR4 dependent. Wound macrophages from C3H/HeJ and C3H/HeOuJ mice expressed CCR4 and CCR5, but not CCR1 or CCR3. Wound macrophage recruitment was not altered in CCR5(-/-) mice or in C3H/HeOuJ animals injected with neutralizing anti-CCL3 and anti-CCL5 antibodies. Neutralization of the CCR4 ligand CCL17 in C3H/HeJ mice did not alter wound macrophage populations. There was a twofold increase in collagen content and number of neovessels in 21-day-old wounds in C3H/HeJ vs. C3H/HeOuJ mice. There were no differences between strains in the number of myofibroblasts in the wounds 7 or 21 days postwounding. The increased fibrosis and angiogenesis in wounds from /HeJ mice correlated with higher concentrations of transforming growth factor-β and fibroblast growth factor 2 in wound fluids from these animals. Wound fluids did not contain detectable lipopolysaccharide and did not induce IκBα degradation in J774.A1 macrophages. Results support a role for endogenous ligands of TLR4 in the regulation of inflammation and repair in sterile wounds.