Release Of Anti-inflammatory Cytokines Research Articles

Galactomannan-graft-poly(methyl methacrylate) nanoparticles induce an anti-inflammatory phenotype in human macrophages.

Macrophages are immune cells that can be activated into either pro-inflammatory M1 or anti-inflammatory M2 phenotypes. Attempts to modulate macrophage phenotype using drugs have been limited by targeting issues and systemic toxicity. This study investigates the effect of drug-free self-assembled hydrolyzed galactomannan-poly(methyl methacrylate) (hGM-g-PMMA) nanoparticles on the activation of the human monocyte-derived macrophage THP-1 cell line. Nanoparticles are cell compatible and are taken up by macrophages. RNA-sequencing analysis of cells exposed to NPs reveal the upregulation of seven metallothionein genes. Additionally, the secretion of pro-inflammatory and anti-inflammatory cytokines upon exposure of unpolarized macrophages and M1-like cells obtained by activation with lipopolysaccharide + interferon-γ to the NPs is reduced and increased, respectively. Finally, nanoparticle-treated macrophages promote fibroblast migration in vitro. Overall, results demonstrate that hGM-g-PMMA nanoparticles induce the release of anti-inflammatory cytokines by THP-1 macrophages, which could pave the way for their application in the therapy of different inflammatory conditions, especially by local delivery.

CONTEMPORARY OPINIONS ON THE PECULIARITIES OF ORAL MUCOSA WOUNDS HEALING: A LITERATURE REVIEW

The purpose of the study is to update data on the features of oral mucosa (OM) wound healing through a systematic assessment of sources of scientific and medical information. Materials and Methods. An analysis of the data obtained during the information search in the online databases “PubMed”, “SciELO”, “Medscape”, and “Science of Ukraine: access to knowledge” was performed using the key words (tags): “mucous membrane of the oral cavity”, “oral mucosa”, “wounds of the mucous membrane”, “healing”, “regeneration”. Publications in periodical scientific issues, methodological recommendations, and reports were included in the list of sources of information. Results. According to the results of clinical observations, experimental studies on laboratory animals and volunteer patients, it was established that the healing of the OM wounds is qualitatively different from a similar process on the skin. This fact was established for both humans and animal models. Wound healing in the human body is a well-defined typical process aimed at restoring tissues after damage. Unlike the skin, OM wounds heal relatively quickly and with little or no scar tissue. And all this happens against the background of constant movement of soft tissues, stress (tension), mechanical abrasion, and contact with a large number of microorganisms in oral fluid. The leading factors of higher-quality regeneration of OM can be considered a moist wound healing environment, direct contact with the protective and regenerative systems of oral fluid which contains a high concentration of commensal microorganisms with immunomodulatory properties and more than 1000 protective and regulatory factors of saliva. There are distinct differences in the properties of the germ layer cells between the skin and OM and the cytokine profile of wound healing is also significantly different. Most reactions that take place in the main phases of the wound process in the oral cavity are faster and more intense. The processes of accumulation of collagen and elastin fibers, remodeling of the intercellular matrix (amorphous substance) are more qualitative. Conclusions: the data from the literature and the results of a significant number of studies allow us to state that faster wound closure, presence of saliva, faster immune response, increased release of anti-inflammatory cytokines, matrix metalloproteinase-mediated cleavage of chemokines, and remodeling of the extracellular matrix contribute to better wound healing and reduced scar formation on the OM, which, unfortunately, does not relate to the skin.

Mesenchymal stromal/stem cells: breaking the deadlock in the treatment of multiple organ dysfunction syndrome

Mesenchymal stromal/stem cells: breaking the deadlock in the treatment of multiple organ dysfunction syndrome

Toll-like receptor 7 regulates cardiovascular diseases.

Cardiovascular disease (CVD) is the major leading cause of morbidity and mortality worldwide. According to the pro-inflammatory nature of CVD, recent studies highlighted the immune system's role in its pathogenesis and development. Toll-like receptors (TLRs) have been identified as dominant innate immune receptors. TLR-7 is an intracellular receptor expressed on endosomes or cytoplasmic reticulum and is responsible for detecting damage-associated molecular patterns, which are remarkable during inflammation and viral infection. In addition to immune cells, TLR-7 is expressed in endothelial cells, vascular smooth muscle cells, and platelets. TLR-7 ligands are single-stranded ribonucleic acid (ssRNA) and short interfering RNA, which can activate the signaling pathway and lead to both inflammatory (e.g., interleukin-1 (IL-1), IL-6, IL-12, tumor necrosis factor- α (TNF-α)) and anti-inflammatory (e.g., IL-10) cytokines release. By growing evidence, it has been proven that TLR-7 activated platelets can increase the risk of thrombus formation by neutrophil aggregation. At the same time, they have a protective role against thrombosis by releasing granulocyte-macrophage colony-stimulating factors. The same two-sided effect was observed between TLR-7 and atherosclerotic plaque formation. Moreover, recent studies explained an association between TLR-7 activation and increased risk of complete heart block, myocarditis, left ventricular remodeling, and rupture. Here we review the rapid progress that has been made in this field, which has improved our understanding of TLR-7 function in CVDs, and discuss the current treatments targeting this receptor.

S572 A Pilot Study for Precision Nutrition in Irritable Bowel Syndrome: In-Vitro Stimulation of Pro-and Anti-inflammatory Cytokine Release

Introduction: Inflammation plays a role in the pathogenesis of irritable bowel syndrome (IBS). Foods can trigger and exacerbate IBS flare-ups and symptoms. Diet-induced inflammation is characterized by the release of cytokines as a common feature. The lack of evidence regarding which diet is ideal for IBS underlined the need for personalized and more precise dietary treatment options. The objective of this study was to determine in-vitro the degree of blood inflammatory cytokines release in response to food antigens exposure in subjects with IBS. Methods: Blood samples were collected at Oxford Biomedical Technologies, Inc. from 12 subjects diagnosed with IBS. Whole blood was diluted with buffered physiologic saline, and then an aliquot was pipetted into eight reaction wells, each containing a single food extract. Following a predetermined incubation period at 37°C, all specimens were stored at -20°C until cytokine analysis were performed. Cytokines [interleukin-8 (IL) and IL-10)] reactivity to food antigens challenge was evaluated using Bio-Plex 200 System (Bio-Rad, CA). The IBS-Severity Scoring System (IBS-SSS) was used to measure the severity and intensity of symptoms. The questionnaire scores range from 0 to 500, with cutoffs rated as mild (75-175), moderate (175-300), and severe ( >300). The study received approval from an independent Institutional Review Board (IRB), and all statistical analyses were performed using SPSS version 27.0 (IBM Corp., NY). Results: Mean age was 52.2±17.5 years, 10 (83%) were female and had a BMI of 26.2±5.7 kg/m2. According to IBS-SSS scores, 8 (67%) of the subjects had moderate symptoms, whereas 4 (33%) had severe symptoms. We found statistically significant differences in IL-8 and IL-10 concentrations (pg/mL) release pre- vs. post-antigen exposure to broccoli [(2.17±0.75, P=0.016)]; corn [(1.25±0.44, P=0.018) and (-0.21±0.09, P=0.041)]; milk [(1.40±0.48, P=0.017); egg [(1.17±0.48, P=0.034)]; navy bean [(0.83±0.30, P=0.019) and (-0.14±0.01, P=.004)]; orange [(2.19±1.04, P=0.063)]; tomato [(2.77±1.15, P=0.038) and (-0.26±0.13; P=0.073)]; and wheat [(0.90±0.36, P=0.033) and (-0.27±0.08, P=0.011)] respectively. Conclusion: The findings from this study generate much-needed data to aid the understanding of non-physiological inflammatory responses to foods which can optimize targeted dietary therapy for IBS. Further work is needed to develop a diagnostic assay that could be used to create a precise and personalized diet for clinical practice.

The growing field of immunometabolism and exercise: Key findings in the last 5 years.

This perspective review highlights the impact of physical exercise on immunometabolic responses in the past 5 years. Understanding immunometabolism as a part of immunological research is essential. Furthermore, the roles of both acute and chronic effects of physical exercise on health, aging, and chronic diseases in immunometabolic changes should be elaborated. In immune cells, β2 adrenergic signaling stimulates the preferential mobilization of inflammatory phenotypes, such as CD16+ monocytes and CD8+ T cells, into the bloodstream after a physical exercise session. The mobilization of immune cells is closely related to the availability of energetic substrates for the cell and mechanisms associated with the uptake and oxidation of fatty acids and glucose. These cells, especially senescent T cells, are mobilized to the peripheral tissues and undergo apoptotic signaling, stimulating the creation of a "vacant space" where new cells will be matured and replaced in the circulation. This results in the upregulation of the expression and secretion of anti-inflammatory cytokines (IL-10 and IL-1ra), leading to increased regulatory immune cells that provide immunoregulatory properties. Thus, we suggest that a significant nutrient available to the cell will favor oxidative metabolism, augment ATP production, and consequently maintain the immune cells in their quiescent state, as well as promote rapid activation function. Therefore, based on the studies discussed in this perspective review, we highlight the importance of performing moderate-intensity continuous and high-intensity intermittent aerobic exercises, due to a higher magnitude of energetic demand and release of anti-inflammatory cytokines (IL-6 and IL-10).

Heat-killed probiotic Lactobacillus plantarum affects the function of neutrophils but does not improve survival in murine burn injury

Probiotics have become of interest as therapeutics in trauma or sepsis-induced inflammation due to their ability to affects the immune response. However, their use is still under debate due to the potential risk of septicemia. Therefore, heat-killed probiotics offer a potential alternative, with recent research suggesting a comparable immunomodulating potential and increased safety. In a previous study, we demonstrated decreased mortality by administration of live Lactobacillus plantarum in a mouse burn-sepsis model. Neutrophils are an essential innate defense against pathogens. Therefore, our present study aims to understand the impact of heat-killed probiotic L. plantarum (HKLP) on neutrophil function. Utilizing an in vitro stimulation with HKLP and a burn-infection in vivo model, we determined that administration of HKLP induced significant release of granulocyte-colony stimulating factor (G-CSF) and stimulated the release of pro-and anti-inflammatory cytokines. HKLP had no impact on neutrophil function, such as phagocytosis, oxidative burst, and NETosis, but increased apoptosis and activated neutrophils. HKLP did not improve survival. Together, contrary to our hypothesis, heat-killed probiotics did not improve neutrophil function and survival outcome in a murine severe burn injury model.

Effects of neuronal cell adhesion molecule L1 and nanoparticle surface modification on microglia

Microelectrode arrays for neural recording suffer from low yield and stability partly due to the inflammatory host responses. A neuronal cell adhesion molecule L1 coating has been shown to promote electrode-neuron integration, reduce microglia activation and improve recording. Coupling L1 to surface via a nanoparticle (NP) base layer further increased the protein surface density and stability. However, the exact L1-microglia interaction in these coatings has not been studied. Here we cultured primary microglia on L1 modified surfaces (with and without NP) and characterized microglia activation upon phorbol myristate acetate (PMA) and lipopolysaccharide (LPS) stimulation. Results showed L1 coatings reduced microglia's superoxide production in response to PMA and presented intrinsic antioxidant properties. Meanwhile, L1 decreased iNOS, NO, and pro-inflammatory cytokines (TNF alpha, IL-6, IL-1 beta), while increased anti-inflammatory cytokines (TGF beta 1, IL-10) in LPS stimulated microglia. Furthermore, L1 increased Arg-1 expression and phagocytosis upon LPS stimulation. Rougher NP surface showed lower number of microglia attached per area than their smooth counterpart, lower IL-6 release and superoxide production, and higher intrinsic reducing potential. Finally, we examined the effect of L1 and nanoparticle modifications on microglia response in vivo over 8 weeks with 2-photon imaging. Microglial coverage on the implant surface was found to be lower on the L1 modified substrates relative to unmodified, consistent with the in vitro observation. Our results indicate L1 significantly reduces superoxide production and inflammatory response of microglia and promotes wound healing, while L1 immobilization via a nanoparticle base layer brings added benefit without adverse effects. Statement of significanceSurface modification of microelectrode arrays with L1 has been shown to reduce microglia coverage on neural probe surface in vivo and improves neural recording, but the specific mechanism of action is not fully understood. The results in this study show that surface bound L1 reduces superoxide production from cultured microglia via direct reduction reaction and signaling pathways, increases anti-inflammatory cytokine release and phagocytosis in response to PMA or LPS stimulation. Additionally, roughening the surface with nanoparticles prior to L1 immobilization further increased the benefit of L1 in reducing microglia activation and oxidative stress. Together, our findings shed light on the mechanisms of action of nanotextured and neuroadhesive neural implant coatings and guide future development of seamless tissue interface.

Distinct responses between healthy and cirrhotic human livers upon lipopolysaccharide challenge: possible implications for acute-on-chronic liver failure

Patients with acute-on-chronic liver failure (ACLF) are at risk of developing acute hepatic decompensation and organ failures with an unraveled complex mechanism. An altered immune response toward insults in cirrhotic compared with healthy livers may contribute to the ACLF development. Therefore, we aim to investigate the differences in inflammatory responses between cirrhotic and healthy livers using human precision-cut liver slices (PCLSs) upon the lipopolysaccharide (LPS) challenge. PCLSs prepared from livers of patients with cirrhosis or healthy donors of liver transplantation were incubated ex vivo with or without LPS for up to 48 h. Viability test, qRT-PCR, and multiplex cytokine assay were performed. Regulation of the LPS receptors during incubation or with LPS challenge differed between healthy versus cirrhotic PCLSs. LPS upregulated TLR-2 in healthy PCLSs solely (P < 0.01). Culturing for 48 h induced a stronger inflammatory response in the cirrhotic than healthy PCLS. Upon LPS stimulation, cirrhotic PCLSs secreted more proinflammatory cytokines (IL-8, IL-6, TNF-α, eotaxin, and VEGF) significantly and less anti-inflammatory cytokine (IL-1ra) than those of healthy. In summary, cirrhotic PCLSs released more proinflammatory and less anti-inflammatory cytokines after LPS stimuli than healthy, leading to dysregulated inflammatory response. These events could possibly resemble the liver immune response in ACLF.NEW & NOTEWORTHY Precision-cut liver slices (PCLSs) model provides a unique platform to investigate the different immune responses of healthy versus cirrhotic livers in humans. Our data show that cirrhotic PCLSs exhibit excessive inflammatory response accompanied by a lower anti-inflammatory cytokine release in response to LPS; a better understanding of this alteration may guide the novel therapeutic approaches to mitigate the excessive inflammation during the onset of acute-on-chronic liver failure.

Discovery and Characterization of a Novel Aryl Hydrocarbon Receptor Inhibitor, IK-175, and Its Inhibitory Activity on Tumor Immune Suppression.

Aryl hydrocarbon receptor (AHR) is a transcription factor that regulates the activity of multiple innate and adaptive immune cells subsequent to binding to numerous endogenous and exogenous ligands. For example, AHR is activated by the metabolite kynurenine, which is secreted into the tumor microenvironment by cancer cells leading to broad immunosuppression. Therefore, AHR inhibition provides a novel and ideal approach to stimulate immune-mediated recognition and subsequent eradication of tumor cells. We report here the discovery and characterization of IK-175, a novel, potent and selective AHR antagonist with favorable ADME and pharmacokinetic profiles in preclinical species. IK-175 inhibits AHR activity in experimental systems derived from multiple species including mouse, rat, monkey, and humans. In human primary immune cells, IK-175 decreased AHR target gene expression and anti-inflammatory cytokine release and increased proinflammatory cytokine release. Moreover, IK-175 led to a decrease in suppressive IL17A-, IL-22+ expressing T cells in a Th17 differentiation assay. IK-175 dose dependently blocks ligand-stimulated AHR activation of Cyp1a1 transcription in mouse liver and spleen, demonstrating on-target in vivo activity. IK-175 increases proinflammatory phenotype of the tumor microenvironment in mouse syngeneic tumors and in adjacent tumor-draining lymph nodes. As a monotherapy and combined with an anti-PD-1 antibody, IK-175 demonstrates antitumor activity in syngeneic mouse models of colorectal cancer and melanoma. IK-175 also demonstrates antitumor activity combined with liposomal doxorubicin in syngeneic mouse tumors. These studies provide rationale for targeting AHR in patients with cancer. IK-175 is being evaluated in a phase I clinical trial in patients with advanced solid tumors.

Investigating CTLA‐4 binding to generate novel small‐molecule inhibitor

The CTLA‐4 receptor may be found on the plasma membranes of T‐cells where it acts as a negative regulator of T‐cell activation. When CTLA‐4 receptors bind B7 ligands (CD80/86) found on antigen presenting cells, they activate signaling pathways which, in combination with signaling from T‐cell receptors bound to antigen‐carrying MHC proteins, decrease the inflammatory response. Regulatory T‐cells (Tregs) constitutively express CTLA‐4 on their membranes and have T‐cell receptors that recognize self‐antigens; this allows them to moderate the self‐tolerance of the immune system. Specifically, CTLA‐4 signaling in Tregs leads to the release of anti‐inflammatory cytokines which decrease the proliferation of helper and cytotoxic T‐cells and prevent monocytes, macrophage precursors, from differentiating into macrophages that would produce pro‐inflammatory cytokines. Unfortunately, it is frequently the case that Tregs recognizing cancerous cells accumulate within tumors. This leads to the inability of the body to form an immune reaction against the cancer. For this reason, cancer therapies which inhibit CTLA‐4 signaling are being developed. Current strategies to limit CTLA‐4 signaling have been successful in treating multiple forms of cancer but primarily rely on reducing CTLA‐4 interactions with B7 through monoclonal antibody therapy targeting the extracellular domain of CTLA‐4. Monoclonal antibodies are not particularly convenient as they must be administered through IV infusion and some formulations carry the risk of inducing serum‐sickness, in which the immune system develops a reaction against the foreign anti‐CTLA4 antibodies. However, instead of inhibiting CTLA‐4 binding to B7 with an antibody, it may be possible to inhibit the intracellular signaling of CTLA‐4 that occurs after this binding with a small molecule that is easier to administer. One of the main proteins that binds to and is activated by stimulated CTLA4 receptors is the phosphatase SHP2. SHP2 uses an SH2 domain at its N‐terminus to bind CTLA‐4 through the YVKM motif of the latter. Binding causes a conformational change in the SH2 domain which makes the phosphatase active site on an adjacent domain of SHP2 more accessible. This conformational change also causes SHP2 to unbind from CTLA‐4 so that a new protein can take its place to be activated. Activated SHP2 dephosphorylates many cytoplasmic proteins at their tyrosine residues leading to Treg activation and thus decreased inflammatory response.

Selinexor and COVID-19: The Neglected Warden.

A novel severe acute respiratory distress syndrome coronavirus type 2 (SARS-CoV-2) has been confirmed as the cause of the global pandemic coronavirus disease 2019 (COVID-19). Different repurposed drugs have been trialed and used in the management of COVID-19. One of these agents was the anti-cancer Selinexor (SXR). SXR is an anti-cancer drug that acts by inhibition of nuclear exportin-1 (XPO1), which inhibits transport of nuclear proteins from the nucleus to the cytoplasm, leading to the induction of cell-cycle arrest and apoptosis. XPO1 inhibitors had antiviral effects, mainly against respiratory syncytial virus (RSV) and influenza virus. SXR inhibits transport of SARS-CoV-2 nuclear proteins to the cytoplasm with further inhibition of SARS-CoV-2 proliferation. SXR has the ability to prevent the development of a cytokine storm in COVID-19 by inhibiting the release of pro-inflammatory cytokines with the augmentation release of anti-inflammatory cytokines. In conclusion, SARS-CoV-2 infection is linked with activation of XPO1, leading to the triggering of inflammatory reactions and oxidative stress. Inhibition of XPO1 by Selinexor (SXR), a selective inhibitor of nuclear export (SINE), can reduce the proliferation of SARS-CoV-2 and associated inflammatory disorders. Preclinical and clinical studies are warranted in this regard.

Lipoxin A4 regulates M1/M2 macrophage polarization via FPR2-IRF pathway.

Lipoxin A4 (LXA4) has been shown to have anti-inflammatory activity, but its underlying molecular mechanisms are not clear. Herein, we investigated the potential role of LXA4 in macrophage polarization and elucidated its possible molecular mechanism. The RAW264.7 macrophage cell line was pretreated with LXA4 with or without lipopolysaccharides (LPSs) and interleukin-4 (IL-4). In cultured macrophages, LXA4 inhibited LPS-induced inflammatory polarization, thereby decreasing the release of proinflammatory cell factors (IL-1β, IL-6, TNF-α) and increasing the release of anti-inflammatory cytokines (IL-4 and IL-10). Notably, the inhibitory effect of LXA4 on inflammatory macrophage polarization was related to the downregulation of p-NF-κB p65 and IRF5 activity, which reduced the LPS-induced phenotypic and functional polarization of M1 macrophages via the FPR2/IRF5 signaling pathway. Moreover, LXA4 also induced the IL-4-induced polarization of M2 macrophages by promoting the FPR2/IRF4 signaling pathway. Therefore, LXA4 regulates M1/M2 polarization of macrophages via the FPR2-IRF pathway.

Antioxidant and Immunomodulatory Properties of Chia Protein Hydrolysates in Primary Human Monocyte-Macrophage Plasticity.

Chia (Salvia hispanica L.) seed has high potential in the development of functional food due to its protein content with a special amino acid profile. Among the hematopoietic-derived cells, monocytes are endowed with high plasticity, responsible for their pro- and anti-inflammatory function in M1 and M2 phenotype polarization, respectively. Indeed, monocytes are involved in several oxidative- and inflammatory-associated disorders such as cancer, obesity, and cardiovascular and neurodegenerative diseases. This study was designed to investigate the role of chia protein hydrolysates (CPHs) in primary human monocyte–macrophage plasticity response using biochemical, RT-qPCR, and ELISA assays. Our results showed that CPHs reduce ROS and nitrite output, as pro-inflammatory cytokine secretion, and enhance the expression and release of anti-inflammatory cytokines. In addition, CPHs reverse LPS-associated M1 polarization into M2. These findings open new opportunities for developing nutritional strategies with chia as a dietary source of biopeptides to prevent the development and progression of oxidative- and inflammatory-related diseases.

4-Octyl itaconate regulates immune balance by activating Nrf2 and negatively regulating PD-L1 in a mouse model of sepsis.

Introduction: Sepsis is a major global health challenge with high mortality rates and no effective treatment. Recent studies have suggested that sepsis may be associated with immune system dysfunction. Itaconate may exert anti-inflammatory effects via Nrf2 signaling. Although Nrf2 regulates oxidative/exogenous stress responses and inhibits inflammatory responses, the mechanism via which Nrf2 regulates immune checkpoints in sepsis remains unclear. Objectives: This study aimed to investigate the role of the Nrf2 signaling pathway in sepsis immunosuppression injury by exploring Nrf2 target genes in inflammatory macrophages in a mouse model of sepsis. Methods: We evaluated the effects of 4-octyl itaconate (OI) on pro-inflammatory and anti-inflammatory cytokines in a mouse model of sepsis and RAW264.7 cells. In addition, we investigated if OI could inhibit LPS-induced oxidative stress by activating Nrf2 signaling in vitro and in vivo. Results: OI reduced the release of pro-inflammatory cytokines and increased the release of anti-inflammatory cytokines, thereby inhibiting inflammation. OI increased glutathione synthase (GSS) expression by activating the Nrf2 signaling pathway to promote GSH synthesis, thus, inhibiting oxidative stress. OI inhibited the early release of inflammatory and oxidative stress-related factors to reduce tissue and organ injury in mice with sepsis, while Nrf2 interfered with PD-L1 induction and inhibited PD-L1 expression at an advanced stage to reduce the occurrence of sepsis immunosuppression. Conclusions: This study indicates that Nrf2 is a novel negative regulator of PD-L1 that functions at immune checkpoints and suggests an underlying mechanism for the anti-inflammatory process mediated by Nrf2.

25 (OH) Vitamin D Levels of Patients with COVID-19 are not Associated with the Length of Hospital Stay.

Vitamin D is known to suppress the release of proinflammatory cytokines, increase the release of anti-inflammatory cytokines, and present an immunomodulatory effect. In light of the foregoing, it is suggested that vitamin D may play an important role in the course of COVID-19 infection. This study, therefore, aimed to examine the relationship between vitamin D levels and length of hospital stay of COVID-19 patients. This retrospective study was conducted between March 15th and October 15th, 2020, among 768 patients who were hospitalized due to the diagnosis of COVID-19 infection confirmed with PCR tests taken at the Health Sciences University, Antalya Training and Research Hospital. The study included 39 patients aged 18 - 65 years, whose 25 (OH) vitamin D levels were examined within 3 months prior to the diagnosis with PCR, and whose results were found ≥ 30 ng/mL, and those patients whose 25 (OH) vitamin D levels were examined within 3 months after the diagnosis with PCR, and whose results were found < 30 ng/mL. The patients were grouped according to 25 (OH) vitamin D levels and evaluated in terms of length of hospital stay. Of all the 39 patients in this study, 61.5% were female, 38.5% were male, with a mean age of 48.64 ± 11.79 years. The average of 25 (OH) vitamin D levels of the patients was 21.44 ± 11.17 ng/mL, the average length of hospital stay was 9.41 ± 8.90 days. The length of stay was found to increase significantly in participants who were 45 years and older, who were male, those with chronic diseases, and those with lung involvement detected on thoracic CT imaging at the time of admission. No statistically significant difference appeared with respect to the length of hospital stay when the patients were evaluated according to their 25 (OH) vitamin D levels. No statistically significant relationship was found between the patients' length of hospital stay due to the COVID-19 infection and their 25 (OH) vitamin D levels in patients aged 18 - 65 years. Further prospective clinical studies still need to be conducted with large numbers of patients excluding independent risk factors such as the presence of a chronic disease.

Inflammatory Response to Cobalt-Chromium Alloys Fabricated With Different Techniques.

ABSTRACTObjectivesTo explore the in vitro cytokine expression of human peripheral blood mononuclear cells exposed to cobalt-chromium alloys, manufactured with different techniques, in comparison with commercially pure titanium grade 4 and titanium alloy grade 23.Material and MethodsPeripheral blood mononuclear cells (PBMC) were collected from 10 healthy blood donors and exposed to machine-ground coin-shaped: (a) cobalt-chromium (Co-Cr) specimens (n = 5) manufactured by four techniques, i.e. cast, milled, laser melted and presintered milled; (b) commercially pure titanium grade 4; and (c) titanium alloy grade 23. The cells were cultured for 4, 24 and 72 hours followed by investigations of pro- and anti-inflammatory cytokine release using Bio-Plex Pro™.ResultsIn general, the PBMC produced significantly more cytokines when exposed to the cast and presintered milled Co-Cr materials compared to laser melted, milled Co-Cr and titanium materials.ConclusionsWithin the limitation of the present study, it may be suggested that cast and presintered milled cobalt-chromium alloys provoke a stronger inflammatory response compared to milled and laser melted cobalt-chromium alloys and titanium materials.

Electroacupuncture promotes microglial M2 polarization in ischemic stroke via annexin A1.

Neuroinflammation is the leading cause of neurological sequelae in ischemic stroke. Recently, we reported that the anti-inflammatory mediator annexin A1 (ANXA1) favored microglial M2 polarization in brain injury. The purpose of this study was to investigate electroacupuncture (EA) treatment and its potentially ANXA1-mediated anti-inflammatory effects in the middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model of stroke. Treatment with EA consisted of dense-sparse frequencies (alternating 4 Hz sparse waves for 1.5 s and 16 Hz dense waves for 1.5 s) at CV24 and GV26. Intracerebroventricular (ICV) injection of Boc-2 (5 µM) or short hairpin RNA (sh)ANXA1 (2 µL) 3 days before EA was performed to block the effects of ANXA1. EA pretreatment enhanced expression of ANXA1 and its receptor, formyl peptide receptor (FPR), when compared to MCAO/R alone. EA treatment also rescued MCAO/R-induced deficits in neurological performance, and learning and memory, and reduced infarct volume. Double immunofluorescent labeling showed that EA prevented MCAO/R-induced changes in microglial activation and morphology. EA also reduced the release of pro-inflammatory cytokines, such as interleukin (IL)-1β, inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF)-α, while increasing the release of anti-inflammatory cytokines, such as arginase-1 (Arg-1) and brain-derived neurotrophic factor (BDNF). All EA-induced effects were either partially or completely prevented by prior administration of FPR antagonist Boc-2 or shANXA1. The current study provides strong evidence that EA treatment has protective effects against ischemic stroke in the MCAO/R mouse model and that the mechanism likely involves the promotion of M2 polarization in microglia via ANXA1.

Physiological Roles of Apoptotic Cell Clearance: Beyond Immune Functions

The clearance of apoptotic cells is known to be a critical step in maintaining tissue and organism homeostasis. This process is rapidly/promptly mediated by recruited or resident phagocytes. Phagocytes that engulf apoptotic cells have been closely linked to the release of anti-inflammatory cytokines to eliminate inflammatory responses. Defective clearance of apoptotic cells can cause severe inflammation and autoimmune responses due to secondary necrosis of apoptotic cells. Recently accumulated evidence indicates that apoptotic cells and their clearance have important physiological roles in addition to immune-related functions. Herein, we review the current understanding of the mechanisms and fundamental roles of apoptotic cell clearance and the beneficial roles of apoptotic cells in physiological processes such as differentiation and development.

Research progress on the role of sialic acid-binding immunoglobulin-like lectin 9 in various diseases

Sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) is a receptor that expresses on the surface of immune cells. It plays an important role in the body’s immune response. Increased expression of Siglec-9 has been reported in infectious diseases, autoimmune diseases and cancer. Pathogenic microorganism and tumor cells can inhibit the recognition and killing of immune cells by upregulating their own specific sialic acid and binding with Siglec-9 on the surface of host immune cells, and suppress the release of pro-inflammatory cytokines and promote the release of anti-inflammatory cytokines, eventually leading to immunosuppression, tumor immune escape and the like. However, the immunosuppressive function of Siglec-9 may be advantageous for diseases such as neutrophil asthma and autoimmune diseases. Therefore, further research on the mechanism of action of Siglec-9 is of great significance.