Septic Inflammation Research Articles

Endothelial Extracellular Vesicle Production and Cargo Property are Altered after Inflammatory Injury

Extracellular vesicles (EVs) play an important role in cell‐cell communication and signal transduction by transferring bioactive cargo contents between cells or tissues. During inflammation, the vascular endothelium is activated and releases vasoactive EVs that alter vascular homeostasis via paracrine or autocrine pathways. In this study, we examined the molecular property and mechanisms of production of EVs derived from endothelial cells (EC) during septic or sterile (thermal injury) inflammation, and during stimulation by inflammatory agonists, including tumor necrosis alpha (TNFa), interleukins (ILs), lipopolysaccharide (LPS) and thrombin. EVs isolated from plasma or cell culture conditioned media were analyzed by flow cytometry using cell specific markers. Size‐based gating of microvesicles (MV) was performed using a mixture of standardized beads of different sizes and absolute MV numbers calculated based on reference beads of known concentration. Immuno‐capture of smaller exosomes was performed with anti‐CD9 coated beads, probed for proteins of interest and visualized by flow cytometry. The results revealed that mice subjected to cecal ligation and puncture‐induced septic injury or thermal injury had increased CD144+ EVs but decreased endothelial nitric oxide synthase (eNOS)+ EVs in plasma as compared to sham‐treated mice. Likewise, endothelial cells stimulated by TNFa, IL‐1b or thrombin release EVs containing a higher level of caveolin‐1 (Cav‐1) and lower level of eNOS compared to non‐stimulated cells. Pre‐treatment with the ROCK inhibitor Y27632 prevented this response. Furthermore, EV‐EC interactions were observed under confocal microscopy. In endothelial cells, internalization of inflammatory EVs induced eNOS translocation from the cell membrane to cytosol. These findings suggest that inflammation alters endothelial production of EVs and their cargo property and function.Support or Funding InformationThis work was supported by NIH grants HL070752, HL126646 and GM097270This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

β1‐Blockers Provide Cardioprotection, Attenuation of Intramyocardial Inflammation and Leukocyte Endothelial Transmigration in Septic Mice

Septic cardiac dysfunction is a key feature of severe sepsis and septic shock, contributing to multiorgan dysfunction syndrome and death. Persistent β adrenergic stimulation is detrimental in sepsis, and specific β1 blockade mitigates excessive systemic inflammation and seems to improve myocardial function. The aim of this study was to investigate the effects of the specific β1 blocker atenolol on the septic mouse myocardium. We also evaluated the survival of septic mice and systemic inflammation in response to atenolol treatment.Mice were rendered septic using intraperitoneal injection of lipopolysaccharide (LPS). The effects of atenolol on the myocardium were assessed by a microarray technique and were confirmed by subsequent western blot, elisa protein assays and confocal microscopy. Infusion of atenolol significantly reduced the intramyocardial production of the proinflammatory cytokines tumor necrosis factor α (TNF‐α), interleukin 1β (IL‐1β) and interleukin‐6 (IL‐6) in the septic model. Cell adhesion molecules and local myocardial chemotaxis were down‐regulated, with a significant reduction in the myocardial levels of angiopoietin 2 (Ang‐2), monocyte chemoattractant protein 1 (MCP‐1), macrophage inflammatory protein 1α (MIP‐1α), MIP‐2, E‐selectin, P‐selectin, intracellular adhesion molecule 1 (ICAM‐1) and vascular cell adhesion molecule 1 (VCAM‐1). Furthermore, atenolol significantly improved left ventricular ejection fraction, arterial pressure and aortic blood flow in septic mice. The median survival time was increased by atenolol in septic model, and the plasma levels of lactate, TNF‐α, IL‐1β, IL‐6, MCP‐1 and MIP‐1α were significantly reduced in response to atenolol treatment.In mice with experimentally induced septic shock, the β1 adrenergic blocker atenolol exerts cardioprotective effects through the tempering of both systemic and local inflammation and by reducing intramyocardial chemotaxis and the synthesis of endothelial transmigration proteins.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Influences of up-regulation of miR-126 on septic inflammation and prognosis through AKT/Rac1 signaling pathway.

To explore the influences of the up-regulation of micro ribonucleic acid (miR)-126 on septic inflammation and prognosis through the AKT/Rac1 signaling pathway. Human pulmonary microvascular endothelial cells (HMVECs) were cultured and transfected with miR-126 mimics. The HMVECs in the logarithmic growth phase in different groups were incubated with thrombin. The transmembrane resistivity of HMVECs was detected as the permeability via Electric Cell-substrate Impedance Sensing (ECIS) system. The endothelial cell space was observed via immunofluorescence. The mouse model of sepsis was then established and the serum was extracted to detect interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The survival curve was plotted based on the death time. The Statistical Product and Service Solutions (SPSS) 22.0 was used for statistical analysis, and p<0.05 suggested that the difference was statistically significant. Thrombin could significantly increase the permeability of HMVECs, while the overexpression of miR-126 markedly inhibited the increased permeability. The overexpression of miR-126 also reduced the endothelial cell space induced by thrombin. In addition, the serum IL-6 and TNF-α levels of sepsis mice in miR-126 overexpression group were significantly decreased compared to those in the control group. Moreover, the death rate of mice exogenously expressing miR-126 was lower than that in the control group. The up-regulation of miR-126 inhibited the septic inflammation and improved the prognosis of sepsis mice through the AKT/Rac1 signaling pathway.

O-GlcNAc Transferase Suppresses Inflammation and Necroptosis by Targeting Receptor-Interacting Serine/Threonine-Protein Kinase 3

Elevated glucose metabolism in immune cells represents a hallmark feature of many inflammatory diseases, such as sepsis. However, the role of individual glucose metabolic pathways during immune cell activation and inflammation remains incompletely understood. Here, we demonstrate a previously unrecognized anti-inflammatory function of the O-linked β-N-acetylglucosamine (O-GlcNAc) signaling associated with the hexosamine biosynthesis pathway (HBP). Despite elevated activities of glycolysis and the pentose phosphate pathway, activation of macrophages with lipopolysaccharide (LPS) resulted in attenuated HBP activity and protein O-GlcNAcylation. Deletion of O-GlcNAc transferase (OGT), a key enzyme for protein O-GlcNAcylation, led to enhanced innate immune activation and exacerbated septic inflammation. Mechanistically, OGT-mediated O-GlcNAcylation of the serine-threonine kinase RIPK3 on threonine 467 (T467) prevented RIPK3-RIPK1 hetero- and RIPK3-RIPK3 homo-interaction and inhibited downstream innate immunity and necroptosis signaling. Thus, our study identifies an immuno-metabolic crosstalk essential for fine-tuning innate immune cell activation and highlights the importance of glucose metabolism in septic inflammation.

Sepsis and acute kidney injury as two-way street: values of biomarkers

The brief review, dedicated to Septic Acute Injury (S-AKI) - the syndrome simultaneously corresponding to criteria of sepsis and acute kidney Injury. Sepsis or AKI are diagnosed 30-50 % of critical patients. Sepsis is promoting the developing of AKI and AKI is promoting the development of sepsis. Morbidity and lethality in S-AKI is higher than that is sepsis and in AKI separately. The main mechanisms of the development of: a) AKI in sepsis - the toxic septic blood containing huge amounts of proinflammatory factors damage the renal tubules resulting tubular disfunction; b) sepsis in AKI - uremia is damaging distal organs and functions of immune systems which provoke sepsis development. For early diagnostics of S-AKI in patients admitting in critical care units the simultaneous measurements and monitoring of sepsis and kidney biomarkers are to be made. The problems of such measurements is that AKI decreases the clearance of septic markers and their levels are increasing in noninfectious conditions. From the other hand in septic conditions inflammation can increase the levels of renal markers independently of renal pathologies. In general in sepsis, AKI and in S-AKI the increased levels of sepsis markers reflect simultaneously severity of infectious inflammation and of renal disfunction, and kidney markers reflect simultaneously severity of renal disfunction and of infectious inflammation. The correction of cut-off values of septic markers used for S-AKI diagnostics must be based on the degree of severity of renal disfunction in critical patients.

Inducement of experimental Abdominal Adhesions (literature review)

Adhesive disease of the abdominal cavity is a common medical problem that impairs the patients’ life quality. Adhesive intestinal obstruction ranks first in the structure of acute bowel obstruction. The levels of complications and postoperative mortality are not likely to decrease. Consequently, the studies on preventing adhesive disease are still in progress, which requires an animal model to induce abdominal adhesive process. Numerous factors of peritoneum injury result in adhesion formation. Experimental surgery offers various techniques of inducing the adhesive process in the abdominal cavity based on mechanical, chemical, biological, implantation injury factors. Recent trends in intra-abdominal adhesion stimulation are designed to approximate at maximum an animal model and present surgical and gynecologic procedures. In the review article, we survey and systematize different ways of inducing intra-abdominal adhesive process with various injury factors. The choice of study animal, the ways of peritoneum injury, followed by septic or aseptic inflammation are analyzed. The rating scales for the severity of adhesive process are also organized and compared. The number of existing models is large which is evident of the outstanding problem and promising outlook of scientific research.

Glucosamine improves survival in a mouse model of sepsis and attenuates sepsis-induced lung injury and inflammation

The aim of the current study was to investigate the effects of glucosamine (GlcN) on septic lethality and sepsis-induced inflammation using animal models of mice and zebrafish. GlcN pretreatment improved survival in the cecal ligation and puncture (CLP)-induced sepsis mouse model and attenuated lipopolysaccharide (LPS)-induced septic lung injury and systemic inflammation. GlcN suppressed LPS-induced M1-specific but not M2-specific gene expression. Furthermore, increased expressions of inflammatory genes in visceral tissue of LPS-injected zebrafish were suppressed by GlcN. GlcN suppressed LPS-induced activation of mitogen-activated protein kinase (MAPK) and NF-κB in lung tissue. LPS triggered a reduction in O-GlcNAc levels in nucleocytoplasmic proteins of lung, liver, and spleen after 1 day, which returned to normal levels at day 3. GlcN inhibited LPS-induced O-GlcNAc down-regulation in mouse lung and visceral tissue of zebrafish. Furthermore, the O-GlcNAcase (OGA) level was increased by LPS, which were suppressed by GlcN in mouse and zebrafish. OGA inhibitors suppressed LPS-induced expression of inflammatory genes in RAW264.7 cells and the visceral tissue of zebrafish. Stable knockdown of Oga via short hairpin RNA led to increased inducible nitric oxide synthase (iNOS) expression in response to LPS with or without GlcN in RAW264.7 cells. Overall, our results demonstrate a protective effect of GlcN on sepsis potentially through modulation of O-GlcNAcylation of nucleocytoplasmic proteins.

Dietary Intake of Ascorbic Acid Attenuates Lipopolysaccharide-Induced Sepsis and Septic Inflammation in ODS Rats.

The aim of this study was to verify the protective effects of ascorbic acid (AsA) against lipopolysaccharide (LPS)-induced sepsis. The study was conducted using osteogenic disorder Shionogi (ODS) rats, which are unable to synthesize AsA. Male ODS rats (6 wk old) were fed either an AsA-free diet (AsA-deficient group), a diet supplemented with 300 mg/kg AsA (control group), or a diet supplemented with 3,000 mg/kg AsA (high-AsA group) for 8 d. On day 8, all the rats were intraperitoneally injected with LPS (15 mg/kg body weight). Forty-eight hours after the injection, the survival rates of the rats in the control (39%) and the high-AsA (61%) groups were significantly higher than that in the AsA-deficient group (5.5%). Next, we measured several inflammatory parameters during 10 h after administering LPS. At 6 h, elevated serum levels of markers for hepatic and systemic injuries were suppressed in rats fed AsA. Similarly, 10 h after LPS injection, the elevation in the serum levels of markers for renal injury were also suppressed proportionally to the amount of AsA in the diet. The elevated serum concentrations of TNFα and IL-1β by LPS in the AsA-deficient group decreased in groups fed AsA. Hematic TNFα mRNA levels at 6 h after the LPS injection were also lowered by feeding AsA. These results demonstrated that the dietary intake of AsA improved the survival rates and suppressed the inflammatory damage, in a dose-dependent manner, caused during sepsis induced by LPS in ODS rats.

Synthesis of 99m Tc-roxithromycin: A novel diagnostic agent to discriminate between septic and aseptic inflammation.

Roxithromycin is a second-generation macrolide antibiotic derived from erythromycin. In the current study, roxithromycin (ROX) was successfully labeled with technetium-99m for early diagnosis of bacterial infection and discrimination between septic and aseptic inflammation. The highest radiochemical purity of ≥95% was achieved by investigating different labeling parameters such as pH, ligand/reducing agent concentration, temperature, and amount of stabilizing agent. For this purpose, 0.3-0.5mg ligand, 2-6μg SnCl2 ·2H2 O as a reducing agent at basic pH (8-10 pH) and 2mg mannitol used as a stabilizing agent, in the end, 370MBq 99m Tc added into the reaction vials and incubated for a wide range of temperature (-4 to 65°C). The percent radiochemical purity of 99m Tc-roxithromycin was assessed with the help of the radio-thin-layer chromatography technique. The characterization studies were carried out using electrophoresis and Radio-HPLC techniques as well as saline stability and serum stability studies were also performed. Furthermore, biodistribution study was also performed in an inflamed animal model to discriminate between septic (heat-killed Staphylococcus aureus) and aseptic (turpentine oil) inflammatory lesions. The results were elaborated that 99m Tc-roxithromycin (99m Tc-ROX) was clearly bounded at the septic inflammation site (T/NT ratio of 7.08±1.14) at 30min postadministration, and maximum accumulation was seen in heart, lungs, liver, stomach, kidneys, and intestine. The results were suggested that 99m Tc-ROX might be used to discriminate between septic and aseptic inflammatory lesions at an early stage.

Thymulin, free or bound to PBCA nanoparticles, protects mice against chronic septic inflammation.

In the present work, we aimed to study the effects of free and polybutylcyanoacrylate nanoparticle-bound thymulin on immune cell activity in mice with chronic inflammation. NF-κB, MAPK, and PKC-θ signaling pathway activity was assessed, alongside Hsp72, Hsp90-α, and TLR4 expression and levels of apoptosis. In addition, plasma cytokines and blood and brain melatonin and serotonin levels were measured. In mice treated with gradually raised doses of lipopolysaccharide, significant increases in the activity of the signaling pathways tested, heat-shock protein and TLR4 expression, lymphocyte apoptosis, and plasma proinflammatory cytokine levels were noted. Moreover, we observed significantly heightened serotonin concentrations in the plasma and especially the brains of mice with inflammation. In contrast, melatonin levels were reduced in the tissues examined, particularly so in the brain. Treatment of these mice with thymulin alleviated fever, reduced apoptosis, increased splenic cell number, and decreased cytokine production, Hsp72, Hsp90, and TLR4 expression, and the activity of the signaling pathways examined. In addition, thymulin partially restored brain and blood serotonin and melatonin levels. Thus, thymulin suppressed the proinflammatory response in LPS-treated mice, indicating the potential of thymulin co-therapy in the treatment of sepsis. Nanoparticle-bound thymulin was more effective in several respects.

Podoplanin: An emerging cancer biomarker and therapeutic target.

Podoplanin (PDPN) is a transmembrane receptor glycoprotein that is upregulated on transformed cells, cancer associated fibroblasts and inflammatory macrophages that contribute to cancer progression. In particular, PDPN increases tumor cell clonal capacity, epithelial mesenchymal transition, migration, invasion, metastasis and inflammation. Antibodies, CAR‐T cells, biologics and synthetic compounds that target PDPN can inhibit cancer progression and septic inflammation in preclinical models. This review describes recent advances in how PDPN may be used as a biomarker and therapeutic target for many types of cancer, including glioma, squamous cell carcinoma, mesothelioma and melanoma.

High-Mobility Group Box 1-Induced Complement Activation Causes Sterile Inflammation.

High-mobility group box 1 (HMGB1), a well-known danger-associated molecular pattern molecule, acts as a pro-inflammatory molecule when secreted by activated immune cells or released after necrotic cell damage. HMGB1 binds to immunogenic bacterial components and augments septic inflammation. In this study, we show how HMGB1 mediates complement activation, promoting sterile inflammation. We show that HMGB1 activates the classical pathway of complement system in an antibody-independent manner after binding to C1q. The C3a complement activation product in human plasma and C5b-9 membrane attack complexes on cell membrane surface are detected after the addition of HMGB1. In an acetaminophen (APAP)-induced hepatotoxicity model, APAP injection reduced HMGB1 levels and elevated C3 levels in C1q-deficient mouse serum samples, compared to that in wild-type (WT) mice. APAP-induced C3 consumption was inhibited by sRAGE treatment in WT mice. Moreover, in a mouse model of brain ischemia–reperfusion injury based on middle cerebral arterial occlusion, C5b-9 complexes were deposited on vessels where HMGB1 was accumulated, an effect that was suppressed upon HMGB1 neutralization. We propose that the HMGB1 released after cell necrosis and in ischemic condition can trigger the classical pathway of complement activation to exacerbate sterile inflammation.

Anti-Anisakis sp. antibodies in serum of patients with sepsis and their relationship with γδ T cells and disease severity

Immunosuppression in sepsis reduces both αβ and γδ T cell subsets. Anisakis sp. is a parasitic nematode with a high prevalence in Spain. Previous contact with the parasite is related to a decrease in γδ T cells. Anti-Anisakis antibodies were measured and related to αβ and γδ T cells in 114 septic patients versus 97 healthy controls. Significant differences were seen with respect to the groups with severe sepsis and septic shock where lower anti-Anisakis levels were observed. A similar decrease appeared in the case of specific IgM with significant differences between the groups of control/uncomplicated sepsis versus severe sepsis and septic shock. These differences were also apparent in the case of specific IgA. The lowest IgE levels were detected in the septic shock group. Anti-Anisakis IgG levels significantly increased in septic shock groups compared with the controls. We observed positive correlations among anti-Anisakis IgA levels and all γδ T cell subsets. There were negative correlations among IgA levels and APACHE and SOFA indices. Greater contact with the parasite (IgG) was directly related with septic shock, inflammation and markers of sepsis severity. A lack of protection in the mucosa (IgA and γδ T cells) was associated with the disease severity.

Norepinephrine Contributes to Enterocyte Damage in Septic Shock Patients: A Prospective Cohort Study.

In septic patients, both systemic inflammation and splanchnic hypoperfusion may cause enterocyte damage. Catecholamines may exert additional detrimental effects on mesenteric blood flow in these patients, and thereby contribute to this damage. Enterocyte damage itself results in impairment of gut barrier function and consequent translocation of bacteria/toxins. This may contribute to multiple organ failure and death by sustaining or amplifying the systemic inflammatory response. The aim of the study was 2-fold: to investigate which factors contribute to enterocyte damage in septic patients, and to assess whether enterocyte damage is associated with a sustained or amplified systemic inflammatory response. In this prospective observational cohort study in 129 patients with septic shock admitted to the ICU, we serially measured plasma levels of Intestinal Fatty Acid-Binding Protein (I-FABP, a marker for enterocyte damage) and of cytokines Tumor Necrosis Factor (TNF)-α, Interferon (IFN)-y, Interleukin (IL)-1β, IL-6, IL-8, IL-1 Receptor Antagonist (RA), and IL-10. Clinical data were collected from electronic patient files. A total of 129 patients were included in the study. The median age of the patients was 67 years [56-74]. The median norepinephrine infusion rate was 0.2 μg/kg/min [0.1-0.5]. Overall, 28-day mortality was 31 (24%). Similar to previous work, I-FABP levels at admission were independently associated with mortality (odds ratio 3.101 [1.138-8.448]). Acute Physiology and Chronic Health Evaluation II score and an increase in norepinephrine infusion rate between days 1 and 3 were independently associated with area under curve I-FABP levels, whereas mean arterial pressure and creatinine levels were not. No correlations were found between any of the measured cytokines and plasma I-FABP levels. Furthermore, high I-FABP levels were not related with the subsequent course of cytokine levels. In patients with septic shock, norepinephrine use is associated with more enterocyte damage. Although enterocyte damage is associated with increased 28-day mortality, it is not associated with a sustained or amplified systemic inflammatory response.

Purulent Hydradenitis. Part II

Purulent hydradenitis is a chronic relapsing disease that affects 4% of the population, caused by uncontrolled growth of hair follicle and apocrine gland cells, which leads to the development of autoimmune and then septic inflammation. The provoking factors are obesity, smoking, formation of apocrine glands in the body. The variety of subordinates of Suppurative hydradenitis, differences in the prognosis and course of the disease, as well as the need to manage patients with this pathology in the surgical department, determine the standardization of the therapeutic algorithm and the objectification of the degree of clinical response to the therapy using scoring scales.

Immersıon Anesthesia with Alfaxalone in a Goldfısh (Carassius auratus)

Abstract An alfaxalone anesthesia protocol was used to perform a coeliotomy in a goldfish diagnosed with multiple ovarian cysts. The 7-year-old, 460g, female goldfish presented for severe coelomic distension and anorexia. Full-body radiographic images were unremarkable, but coelomic ultrasound revealed multiple ovarian cysts. Ultrasound-guided aspiration of a large cyst was performed. Cytology revealed lysed leukocytes that contained numerous intracellular bacilli suggestive of septic suppurative inflammation. An exploratory coeliotomy was performed and 90mL of semi-clear fluid was aspirated from the largest cysts. For anesthesia, three plastic fish tanks were prepared for induction (10mg/L of alfaxalone), maintenance (5mg/L alfaxalone), and recovery (no anesthetic agent). Water in the fish tanks was saturated with oxygen. The goldfish was immersed in the induction tank and once the labyrinthine-righting reflex was lost (5 minutes), the fish was placed in the maintenance tank. The goldfish was then placed on a platform and supported in a supine position on wet Perlon wool. The head of the goldfish was submerged in water while the coelomic area of the surgical field was maintained out of water. During surgery, the respiratory rate (32 to 53 opercula movements per minute) and heart rate (35 to 45beats per minute) were monitored. Butorphanol (0.4mg/kg IM) was administered for analgesia. The anesthetic event was 60 minutes, with the recovery period being 35 minutes. There were no complications associated with recovery and the goldfish returned to its normal position 12 hours after surgery. Immersion anesthesia with alfaxalone permitted deep anesthesia for surgery with an uncomplicated recovery. The anesthetic protocol described appears to be a safe and easy protocol for general practitioners and, furthermore, uses anesthetic agent commonly available to veterinarians.

POLYMORPHISMS WITHIN INNATE IMMUNE RESPONSE, CALCIUM METABOLISM AND LIPID METABOLISM ARE PREDICTORS OF INFECTIVE ENDOCARDITIS

Infective endocarditis (IE) is a septic inflammation of the endocardium generally caused by bacteria. Despite certain advances in treatment, case fatality rate and mortality of IE are still relatively high, particularly in high-risk groups. This requires the development of novel efficient preventive approaches; one of them is a personalized medicine. Recognition of microbial patterns, cytokine and acute phase responses, hemostasis features and alterations in plasma lipid and calcium profile all have been reported to affect pathogenesis and clinical course of IE. We hypothesized that inherited genomic variation in the abovementioned pathways may determine individual susceptibility to IE. Having recruited 124 patients with IE and 300 age-, sex-, and ethnicity-matched healthy controls, we profiled their genomic DNA for 35 functionally significant polymorphisms within the 22 selected genes involved in pathways mentioned above, with the further genetic association analysis. Genotyping was performed using TaqMan allelic discrimination assay while statistical analysis was carried out utilizing SNPStats, a web tool for genetic association analysis. We found that the G/A genotype of the rs1143634 polymorphism within the IL1B gene, the G/T genotype of the rs3212227 polymorphism within the IL12B gene, the A/G genotype of the rs1130864 polymorphism within the CRP gene, and the G allele of the rs1801197 polymorphism within the CALCR gene are associated with a decreased risk of IE whereas the T/T genotype of the rs1205 polymorphism within the CRP gene is associated with a higher risk of IE. Furthermore, heterozygous genotypes of the rs1143634 and rs3212227 polymorphisms were associated with the higher plasma levels of IL-1β and IL-12, respectively, suggesting their possible importance for IE development. Our results indicate that inherited variation in the cytokine, acute phase response, and calcium metabolism pathways may be linked to IE. However, further molecular epidemiology studies are needed to thoroughly uncover the genetic basis of IE.

Micro-anatomical responses in periodontal complexes of mice to calibrated orthodontic forces on the crown.

Correlating mechanical forces with quantifiable physical changes in the dentoalveolar complex. Male 6-week C57BL/6 mice (N=3), micro X-ray-computed tomography; post-analysis software to extract physical changes in periodontal ligament (PDL)-space. Silicone-elastic bands were placed between maxillary molars for 1week, with the contralateral side as internal control. Average displacements between crowns and roots, and changes in PDL-spaces were evaluated by registering X-ray tomograms of experimental and control hemi-maxillae. Histology illustrated mineral formation and resorption-related events within narrowed and widened volumes of the PDL-space. 3D maps of changes in PDL-space between molars illustrated coronal and root displacements of 640μm and 180μm, respectively, compared to 70μm in controls. Orthodontic tooth movement (OTM) specimens exhibited an average net change of -20μm in narrowed and +30μm in widened PDL-spaces. Bone and cementum were affected by the force on molars, and primary cementum was more affected than secondary cementum. This novel approach illustrates the importance of 3D-imaging and analysing 3D alveolar socket subjected to OTM otherwise omitted by 2D micrographs.A measured force on the crown elicits a response related to narrowed and widened regions in the 3D complex. OTM that exceeds PDL-space can illicit biological responses that attempt to restore physiologic PDL-space via remodelling of the periodontium. Regenerated weaker bone due to aseptic inflammation caused by orthodontics could leave patients at a higher risk of bone loss or root resorption if they later develop periodontitis, a form of septic inflammation.

Frontline Science: Myeloid cell-specific deletion of Cebpb decreases sepsis-induced immunosuppression in mice.

Sepsis inflammation accelerates myeloid cell generation to compensate for rapid mobilization of the myeloid progenitors from bone marrow. This inflammation-driven myelopoiesis, however, generates myeloid progenitors with immunosuppressive functions that are unable to differentiate into mature, innate immune cells. The myeloid-derived suppressor cells (MDSCs) expand markedly in the later phases of sepsis, suppress both innate and adaptive immunity, and thus, elevate mortality. Using a murine model with myeloid-restricted deletion of the C/EBPβ transcription factor, we show that sepsis-induced generation of MDSCs depends on C/EBPβ. C/EBPβ myeloid cell-deficient mice did not generate MDSCs or develop immunosuppression and survived sepsis. However, septic mice still generated Gr1+CD11b+ myeloid progenitors at the steady-state levels similar to the control sham mice, suggesting that C/EBPβ is not involved in healthy, steady-state myelopoiesis. C/EBPβ-deficient Gr1+CD11b+ cells generated fewer monocyte- and granulocyte-like colonies than control mice did, indicating reduced proliferation potential, but differentiated normally in response to growth factors. Adoptive transfer of C/EBPβ-deficient Gr1+CD11b+ cells from late septic mice exacerbated inflammation in control mice undergoing early sepsis, confirming they were not immunosuppressive. These results show that C/EBPβ directs a switch from proinflammatory to repressor myeloid cells and identifies a novel treatment target.

Downregulation of the O-GlcNAc signaling promotes activation of the innate immune response in microbial sepsis

Abstract Sepsis is the most common cause of death in intensive care units. Acute systemic inflammatory responses mediate morbidity in microbial sepsis. Studies of immune system metabolism have recently identified the tight link between metabolic reprogramming and immune system activation. A robust increase in glucose metabolism is observed in the initial phase of sepsis, indicating the involvement of glucose metabolism in the pathogenesis of sepsis. However, the role of individual glucose metabolism pathways in the regulation of septic inflammation is poorly understood. The hexosamine synthesis pathway (HBP) is a unique glucose metabolism pathway leading to protein modification by the O-linked b-N-acetylglucosamine (O-GlcNAc), a process known as O-GlcNAcylation. Here we report a critical role of HBP-associated O-GlcNAc signaling in modulating septic inflammation. Activation of TLR4 signaling results in decreased HBP flux activity and protein O-GlcNAcylation in macrophages. Decreased O-GlcNAc signaling is also observed in peritoneal macrophages following cecal ligation and puncture (CLP)-induced experimental sepsis, indicating that decreased O-GlcNAc signaling may exacerbate septic inflammation. Myeloid-specific deletion (OgtΔmye) of O-GlcNAc transferase (OGT), the key enzyme mediating protein O-GlcNAcylation, leads to increased activation of the NF-κB signaling and cytokine production upon the stimulation with various TLR agonists. Furthermore, OgtΔmye mice show increased susceptibility to LPS-induced endotoxin shock and CLP-induced sepsis. These findings identify a novel link between glucose metabolism and innate immune activation and suggest OGT as a therapeutic target for treating microbial sepsis.