Inflammation In Several Models Research Articles

Apolipoprotein D in Oxidative Stress and Inflammation.

Apolipoprotein D (ApoD) is lipocalin able to bind hydrophobic ligands. The APOD gene is upregulated in a number of pathologies, including Alzheimer's disease, Parkinson's disease, cancer, and hypothyroidism. Upregulation of ApoD is linked to decreased oxidative stress and inflammation in several models, including humans, mice, Drosophila melanogaster and plants. Studies suggest that the mechanism through which ApoD modulates oxidative stress and regulate inflammation is via its capacity to bind arachidonic acid (ARA). This polyunsaturated omega-6 fatty acid can be metabolised to generate large variety of pro-inflammatory mediators. ApoD serves as a sequester, blocking and/or altering arachidonic metabolism. In recent studies of diet-induced obesity, ApoD has been shown to modulate lipid mediators derived from ARA, but also from eicosapentaenoic acid and docosahexaenoic acid in an anti-inflammatory way. High levels of ApoD have also been linked to better metabolic health and inflammatory state in the round ligament of morbidly obese women. Since ApoD expression is upregulated in numerous diseases, it might serve as a therapeutic agent against pathologies aggravated by OS and inflammation such as many obesity comorbidities. This review will present the most recent findings underlying the central role of ApoD in the modulation of both OS and inflammation.

The Degree of Inflammation and Length of Hospital Stay in Acute Exacerbation of COPD Patients After Secretome Administration

Background: Acute exacerbation of COPD (AECOPD) is a decrease in respiratory conditions compared with regular conditions that require additional treatment, increase risk of hospitalization or demand intensive care unit. The neutrophil-to-lymphocyte ratio (NLR) describes the balance between the severity of inflammation and the immune system and is considered as an important systemic inflammatory marker. Length of hospital stay (LHS) is important in predicting the severity of AECOPD, in which longer LHS indicates greater severity of AECOPD. Secretome has been shown to have the ability to exert immunomodulatory effects, reduce lung injury and inflammation in several models of lung inflammation and immune-mediated lung disease. This study aimed to assess the differences between NLR and LHS in AECOPD patients who received a secretome and those who did not.Methods: This study involved 30 AECOPD patients whom assigned into two groups. Secretome and standard therapy were administered in the treatment group, whilst the control group only received the standard therapy. Statistical analysis used different test, the unpaired group difference test using Mann Whitney and the independent test, the paired group difference test using Wilcoxon rank test and Pair test. Result is significant if the P<0.05.Results: NLR value in the treatment group experienced a lower increase than the control group, yet statistically insignificant (P=0,187). Secretome decreased the LHS in AECOPD patients, and statistically significant with (P=0,028). Conclusion: Administration of secretome led to a lower increase in NLR value and decreased LHS AECOPD patients.

Exogenous ketone ester administration attenuates systemic inflammation and reduces organ damage in a lipopolysaccharide model of sepsis

AimsSepsis is a life-threatening condition of organ dysfunction caused by dysregulated inflammation which predisposes patients to developing cardiovascular disease. The ketone β-hydroxybutyrate is reported to be cardioprotective in cardiovascular disease and this may be due to their signaling properties that contribute to reducing inflammation. While exogenous ketone esters (KE) increase blood ketone levels, it remains unknown whether KEs can reduce the enhanced inflammatory response and multi-organ dysfunction that is observed in sepsis. Thus, this study assesses whether a recently developed and clinically safe KE can effectively improve the inflammatory response and organ dysfunction in sepsis. Methods and resultsTo assess the anti-inflammatory effects of a KE, we utilized a model of lipopolysaccharide (LPS)-induced sepsis in which an enhanced inflammatory response results in multi-organ dysfunction. Oral administration of KE for three days prior to LPS-injection significantly protected mice against the profound systemic inflammation compared to their vehicle-treated counterparts. In assessing organ dysfunction, KE protected mice from sepsis-induced cardiac dysfunction as well as renal dysfunction and fibrosis. Furthermore, KE administration attenuated the sepsis-induced inflammation in the heart, kidney, and liver. Moreover, these protective effects occurred independent of changes to enzymes involved in ketone metabolism. ConclusionThese data show that the use of an exogenous KE attenuates the dysregulated systemic and organ inflammation as well as organ dysfunction in a model of severe inflammation. We postulate that this exogenous KE is an appealing and promising approach to capitalize on the protective anti-inflammatory effects of ketones in sepsis and/or other inflammatory responses.

NR4A1-3 nuclear receptor activity and immune cell dysregulation in rheumatic diseases.

The development and progression of immune-mediated rheumatic disease (IMRD) involves dysfunction of innate and adaptive immune cell populations leading to altered responses including inflammasome activation, dysregulated cytokine networks, increased immune cell numbers and multifaceted cell-cell communication. Several rheumatic diseases are further characterized by the presence of autoantibodies, immune complex mediated complement activation and the deficit of peripheral immune tolerance due to reduced regulatory T-lymphocyte cell function. Ultimately, in rheumatic disease the loss in cellular and tissue homeostasis culminates in the advancement of chronic inflammation. The three members of the NR4A subfamily of nuclear receptors are immediate early genes, and act as potent transcriptional responders to changes in the cellular and tissue microenvironment. Subfamily members are rapidly expressed in diseases characterized by inflammation and function to control the differentiation and activity of innate and adaptive immune cells in a cell-type and cell-context specific manner. Rheumatic disease including rheumatoid-, psoriatic-, osteo-arthritis and systemic sclerosis display altered NR4A1-3 activity in controlling immune cell migration and function, production of paracrine signaling molecules, synovial tissue hyperplasia, and regulating cartilage turn-over in vivo. Additionally, NR4A1-3 activities mediate cytokine, prostanoid and growth factor signaling to control angiogenesis, modulate the regulatory functions of mesenchymal stromal cells, alter the activation status of dendritic cells, influence the generation of peripheral myeloid and T-lymphocyte lineages and promote the maintenance of functional regulatory T-cells. Further reports uncover the potential of moderating NR4A 1-3 receptors as therapeutic targets in altering immune tolerance, pathological angiogenesis and controlling inflammation in several models of disease.

The lectin pathway does not contribute to glomerular injury in the nephrotoxic nephritis model

Rapidly progressive crescentic glomerulonephritis occurs in number systemic and primary glomerular diseases, including anti-glomerular basement membrane disease, anti-neutrophil cytoplasmic antibody vasculitis and lupus nephritis. Our understanding of pathogenic mechanisms comes from animal models of disease such as the nephrotoxic nephritis model. The lectin pathway of complement activation has been shown to play a key role in several models of inflammation including renal ischaemia reperfusion. However, the lectin pathway is not required for crescentic glomerulonephritis in the anti-myeloperoxidase model of anti-neutrophil cytoplasmic antibody vasculitis. The aim of the current study was to explore the role of the lectin pathway in the nephrotoxic nephritis model, which is another model of crescentic glomerulonephritis. Nephrotoxic nephritis was induced in wild type and mannan-binding lectin-associated serine protease-2 deficient mice. Diseases were assessed by quantifying glomerular crescents and macrophages, in addition to albuminuria and serum creatinine. There was no difference between wild type and MASP-2 deficient mice in any of the histological or biochemical parameters of disease assessed. In addition, there was no difference in the humoral immune response to sheep IgG. These data show that the lectin pathway of complement activation is not required for the development of crescentic glomerulonephritis in the nephrotoxic nephritis model, reinforcing previous findings in the anti-myeloperoxidase model.

Erythropoietin Gene Therapy Delays Retinal Degeneration Resulting from Oxidative Stress in the Retinal Pigment Epithelium.

Erythropoietin (EPO) plays an important role in erythropoiesis by its action in blocking apoptosis of progenitor cells and protects both photoreceptors and retinal ganglion cells from induced or inherited degeneration. A modified form of EPO, EPO-R76E has attenuated erythropoietic activity but is effective in inhibiting apoptosis, oxidative stress, and inflammation in several models of retinal degeneration. In this study, we used recombinant Adeno Associated Virus (AAV) to provide long-term sustained delivery of EPO-R76E and demonstrated its effects in a mouse model of dry-AMD in which retinal degeneration is induced by oxidative stress in the retinal pigment epithelial (RPE) cells. Experimental vector AAV-EPO-R76E and control vector AAV-GFP were packaged into serotype-1 (AAV1) to enable RPE selective expression. RPE oxidative stress-mediated retinal degeneration was induced by exon specific deletion of the protective enzyme MnSOD (encoded by Sod2) by cre/lox mechanism. Experimental mice received subretinal injection of AAV-EPO-R76E in the right eye and AAV-GFP in the left eye. Western blotting of RPE/choroid protein samples from AAV-EPO-R76E injected eyes showed RPE specific EPO expression. Retinal function was monitored by electroretinography (ERG). EPO-R76E over-expression in RPE delayed the retinal degeneration as measured by light microscopy in RPE specific Sod2 knockout mice. Delivery of EPO-R76E vector can be used as a tool to prevent retinal degeneration induced by RPE oxidative stress, which is implicated as a potential cause of Age-Related Macular Degeneration.

Ribes nigrum Leaf Extract Preferentially Inhibits IFN-γ-Mediated Inflammation in HaCaT Keratinocytes.

Ribes nigrum L. (blackcurrant) leaf extracts, due to high levels of flavonols and anthocyanins, have been shown to exhibit beneficial effects in inflammatory diseases. However, whereas their traditional use has been investigated and validated in several models of inflammation and oxidative stress, the possible impact on skin disorders is still largely unknown. The purpose of this work was to elucidate the effects of R. nigrum leaf extract (RNLE) on keratinocyte-derived inflammatory mediators, elicited by a Th1 or Th2 cytokine milieu. HaCaT cells were challenged with TNF-α, either alone or in combination with the costimulatory cytokines IFN-γ or IL-4, and the release of proinflammatory cytokines and mediators (IL-8, IL-6, s-ICAM-1, and TSLP) was evaluated. The results showed that RNLE preferentially interferes with IFN-γ signaling, demonstrating only negligible activity on TNF-α or IL-4. This effect was attributed to flavonols, which might also account for the ability of RNLE to impair TNF-α/IL-4-induced TSLP release in a cAMP-independent manner. These results suggest that RNLE could have an antiallergic effect mediated in keratinocytes via mechanisms beyond histamine involvement. In conclusion, the discovery of RNLE preferential activity against IFN-γ-mediated inflammation suggests potential selectivity against Th1 type response and the possible use in Th1 inflammatory diseases.

Released Myeloperoxidase Attenuates Neutrophil Migration and Accumulation in Inflamed Tissue.

Neutrophil (PMN) recruitment to sites of insult is critical for host defense, however excessive PMN activity and tissue accumulation can lead to exacerbated inflammation and injury. Myeloperoxidase (MPO) is a PMN azurophilic granule enzyme, which together with H2O2, forms a powerful antimicrobial system designed to kill ingested bacteria. Intriguingly, in addition to intracellular killing of invading microorganisms and extracellular tissue damage due generation of ROS, soluble MPO has been directly implicated in modulating cellular responses and tissue homeostasis. In the current work, we used several models of inflammation, murine and human PMNs and state-of-the-art intravital microscopy to examine the effect of MPO on PMN migration and tissue accumulation. We found that in the absence of functional MPO (MPO knockout, KO mice) inflammatory PMN tissue accumulation was significantly enhanced. We determined that the elevated numbers of PMNs in MPO knockout mice was not due to enhanced viability, but due to increased migratory ability. Acute PMN migration in models of zymosan-induced peritonitis or ligated intestinal loops induced by intraluminal administration of PMN-chemokine CXCL1 was increased over 2-fold in MPO KO compared to wild type (WT) mice. Using real-time intravital imaging of inflamed mouse cremaster muscle and ex vivo PMN co-culture with inflamed endothelial cells (ECs) we demonstrate that elevated migration of MPO KO mice was due to enhanced adhesive interactions. In contrast, addition of soluble recombinant MPO both in vivo and ex vivo diminished PMN adhesion and migration. Although MPO has been previously suggested to bind CD11b, we found no significant difference in CD11b expression in either resting or activated PMNs and further showed that the MPO binding to the PMN surface is not specific to CD11b. As such, our data identify MPO as a novel regulator of PMN trafficking in inflammation.

Interleukin-21 (IL-21) Downregulates Dendritic Cell Cytokine Responses to Helicobacter pylori and Modulates T Lymphocyte IL-17A Expression in Peyer's Patches during Infection.

Interleukin-21 (IL-21), a cytokine produced by many subsets of activated immune cells, is critical for driving inflammation in several models. Using Helicobacter pylori infection as a model for chronic mucosal infection, we previously published that IL-21 is required for the development of gastritis in response to infection. Concomitant with protection from chronic inflammation, H. pylori-infected IL-21-/- mice exhibited limited Th1 and Th17 responses in their gastric mucosa. Here we report that H. pylori-infected IL-21-/- mice express significantly higher levels of IL-17A than H. pylori-infected wild-type (WT) mice in the Peyer's patches and mesenteric lymph nodes. This led us to hypothesize that IL-21 may indirectly regulate H. pylori-specific T cell responses by controlling dendritic cell (DC) functions in mucosa-associated lymphoid tissue. It was found that IL-21 treatment reduced the ability of dendritic cells to produce proinflammatory cytokines in response to H. pylori While H. pylori increased the expression of costimulatory proteins on DCs, IL-21 reduced the expression of CD40 in the presence of H. pylori Also, Th17 recall responses were intact when DCs were used as antigen-presenting cells in the presence of IL-21, but IL-21 did impact the ability of DCs to induce antigen-specific proliferation. These data suggest that IL-21, while proinflammatory in most settings, downregulates the proinflammatory cytokine microenvironment through modulating the cytokine expression of DCs, indirectly modifying IL-17A expression. Understanding how these proinflammatory cytokines are regulated will advance our understanding of how and why H. pylori infection may be tolerated in some individuals while it causes gastritis, ulcers, or cancer in others.

The High Costs of Low-Grade Inflammation: Persistent Fatigue as a Consequence of Reduced Cellular-Energy Availability and Non-adaptive Energy Expenditure.

Chronic or persistent fatigue is a common, debilitating symptom of several diseases. Persistent fatigue has been associated with low-grade inflammation in several models of fatigue, including cancer-related fatigue and chronic fatigue syndrome. However, it is unclear how low-grade inflammation leads to the experience of fatigue. We here propose a model of an imbalance in energy availability and energy expenditure as a consequence of low-grade inflammation. In this narrative review, we discuss how chronic low-grade inflammation can lead to reduced cellular-energy availability. Low-grade inflammation induces a metabolic switch from energy-efficient oxidative phosphorylation to fast-acting, but less efficient, aerobic glycolytic energy production; increases reactive oxygen species; and reduces insulin sensitivity. These effects result in reduced glucose availability and, thereby, reduced cellular energy. In addition, emerging evidence suggests that chronic low-grade inflammation is associated with increased willingness to exert effort under specific circumstances. Circadian-rhythm changes and sleep disturbances might mediate the effects of inflammation on cellular-energy availability and non-adaptive energy expenditure. In the second part of the review, we present evidence for these metabolic pathways in models of persistent fatigue, focusing on chronic fatigue syndrome and cancer-related fatigue. Most evidence for reduced cellular-energy availability in relation to fatigue comes from studies on chronic fatigue syndrome. While the mechanistic evidence from the cancer-related fatigue literature is still limited, the sparse results point to reduced cellular-energy availability as well. There is also mounting evidence that behavioral-energy expenditure exceeds the reduced cellular-energy availability in patients with persistent fatigue. This suggests that an inability to adjust energy expenditure to available resources might be one mechanism underlying persistent fatigue.

Antibody Neutralization of CXCL10 in Vivo Is Dependent on Binding to Free and Not Endothelial-bound Chemokine: IMPLICATIONS FOR THE DESIGN OF A NEW GENERATION OF ANTI-CHEMOKINE THERAPEUTIC ANTIBODIES

To improve our understanding of properties that confer successful inhibition of chemokines in vivo, we analyzed anti-murine CXCL10 monoclonal antibodies (mAb) having different characteristics. 1B6 displayed potent inhibition of cell recruitment in vitro with an IC50 of 0.5 nm but demonstrated little efficacy in various animal models of human disease. On the contrary, 1F11 showed efficacy in several models of inflammation yet was less potent at inhibiting chemotaxis in vitro with an IC50 of 21 nm Furthermore, we observed that 1B6 displayed a rapid dose-dependent clearance (t½ 10-60 h) in contrast to 1F11, which presented a dose-proportional pharmacokinetic profile and a half-life of 12 days. Moreover, 1B6 recognized glycosaminoglycan (GAG)-bound CXCL10, resulting in target-mediated clearance, which was corroborated using CXCL10-deficient mice. In contrast to 1B6, 1F11 inhibited the interaction of CXCL10 with GAGs, did not recognize GAG-bound CXCL10, and did not display target-mediated drug disposition. Confirming previous animal studies, 1B6 was poor at reversing glycemia in a model of type 1 diabetes, whereas 1F11 induced early and prolonged control of diabetes. Furthermore, when using 1A4, a subsequently generated anti-mCXCL10 mAb that shares the property with 1F11 of being unable to recognize CXCL10 immobilized on GAG, we observed a similar superior control of diabetes as compared with 1B6. We therefore concluded that targeting chemokines with antibodies such as 1B6 that recognize the more abundant GAG-bound form of the chemokine may not be the optimal strategy to achieve disease control.

Suppression of innate inflammation and immunity by interleukin‐37

IL-37 is unique in the IL-1 family in that unlike other members of the family, IL-37 broadly suppresses innate immunity. IL-37 can be elevated in humans with inflammatory and autoimmune diseases where it likely functions to limit inflammation. Transgenic mice expressing human IL-37 (IL37-tg) exhibit less severe inflammation in models of endotoxin shock, colitis, myocardial infarction, lung, and spinal cord injury. IL37-tg mice have reduced antigen-specific responses and dendritic cells (DCs) from these mice exhibit characteristics of tolerogenic DCs. Compared to aging wild-type (WT) mice, aging IL37-tg mice are protected against B-cell leukemogenesis and heart failure. Treatment of WT mice with recombinant human IL-37 has been shown to be protective in several models of inflammation and injury. IL-37 binds to the IL-18 receptor but then recruits the orphan IL-1R8 (formerly TIR8 or SIGIRR) in order to function as an inhibitor. Here, we review the discovery of IL-37, its production, release, and mechanisms by which IL-37 reduces inflammation and suppresses immune responses. The data reviewed here suggest a therapeutic potential for IL-37.

Abstract 350: The Pro-atherosclerotic Milieu Converts a Sub-population of Murine Peripheral T Regulatory Cells to a Non-suppressive Th1-like Foxp3+IFNγ+ Phenotype.

CD4+ T cell subsets play diverse roles in inflammation but may also display limited plasticity. The existence of a population of Foxp3+ T regulatory (Treg) cells that co-expresses Interferon-γ (IFNγ) has been demonstrated in several models of inflammation. In atherosclerosis, circulating Treg content inversely corresponds with atherogenesis, suggesting that inflammation might affect peripheral Treg (pTregs) maintenance. Thus, we sought to examine the fate of pTregs within atherosclerotic Apolipoprotein E-deficient (Apoe-/-) mice. Foxp3+IFNγ+ T cells were elevated within the aorta, spleen, and peripheral lymph nodes (PLNs) of atherosclerotic Apoe-/- versus C57BL/6 mice. Further phenotyping of Foxp3+IFNγ+ T cells revealed variable expression of Treg and Th1 markers, including low CTLA4, GITR, CD25 expression, equivalent PD1, CD73, FR4, expression and elevated Tbet, CD119, CXCR3, and CCR5 expression. To determine whether Foxp3+IFNγ+ T cells arise from de novo differentiation or peripheral conversion, we performed fate tracking experiments with co-adoptively transferred naïve T cells and pTregs, or lineage tracing Foxp3yfp-cre+ R26RtdTomato+ pTregs, to aged Apoe-/- mice. Naïve T cells failed to generate Foxp3+IFNγ+ T cells. In contrast, adoptively transferred Tregs maintained Foxp3 expression (50-60%) or adopted a Foxp3+IFNγ+ T phenotype (40-50%) within the spleen, peri-aortic lymph nodes, and aorta. To test the functionality of IFNγ+ Tregs, we isolated IFNγ+ pTregs, IFNγ- pTregs, and Foxp3GFP+ Tregs for T cell suppression assays. While IFNγ- pTregs and Foxp3GFP+ pTregs were equivalently suppressive, IFNγ+ pTregs failed to adequately suppress T cell proliferation. Together these results demonstrate that atherogenic inflammation affects the maintenance of pTregs, resulting in the generation of a subset of dysfunctional Foxp3+IFNγ+ T cells.

The pro-atherosclerotic milieu promotes the conversion of murine T regulatory cells to a spectrum of Foxp3+IFNγ+ T cell phenotypes. (IRC8P.481)

Abstract T cell subsets play diverse roles in inflammation but may also display limited plasticity. The existence of a population of Foxp3+ T regulatory (Treg) cells that co-express Interferon-γ (IFNγ), has been demonstrated in several models of inflammation. In atherosclerosis, circulating Treg content inversely corresponds with atherogenesis, suggesting that inflammation affects peripheral Treg (pTregs) maintenance. Thus, we sought to examine the fate of pTregs within atherosclerotic Apolipoprotein E-deficient (Apoe-/-) mice. Foxp3+IFNγ+ T cells were elevated within the aorta, spleen, and peripheral lymph nodes (PLNs) of atherosclerotic Apoe-/- mice in comparison to C57BL/6 mice. Further phenotyping of Foxp3+IFNγ+ T cells revealed variable expression of both Treg and Th1 markers, including PD1, GITR, CD25, CD73, Tbet, CXCR3, and CCR5. To determine whether Foxp3+IFNγ+ T cells arise from de novo differentiation or peripheral conversion, we performed fate tracking experiments with co-adoptively transferred naïve T cells and pTregs within Apoe-/- mice. In this system, naïve T cells failed to generate Foxp3+IFNγ+ T cells. In contrast, adoptively transferred Tregs lost Foxp3 expression (50%), maintained Foxp3 expression (40-45%), or adopted a Foxp3+IFNγ+ phenotype (5-10%) within all of the tissues examined. Together, these results demonstrate that inflammation during atherogenesis affects the maintenance of pTregs, resulting in the generation of phenotypically diverse Foxp3+IFNγ+ T cells.

Assessment of circulatory and pulmonary endothelin-1 levels in a lavage-induced surfactant-depleted lung injury rabbit model with repeated open endotracheal suctioning and hyperinflation

Aims:Endothelin-1 (ET-1) is a mediator of various physiological and pathological processes, including vascular inflammation, cell proliferation and vasoconstriction. Attenuation of ET action using ET-1 antagonists reduces pulmonary vascular leakage and inflammation in several models of lung injuries and experimental acute respiratory distress syndrome (ARDS). Based on these earlier reports, the current study investigates the patterns of ET-1 levels in circulation and pulmonary tissues in an experimental model of lavage-induced surfactant-depleted lung injury. Additionally, we also test the effects of open endotracheal suctioning (OES) and hyperinflation (HI) as recruitment maneuver following OES on ET-1 levels. Main methods:Briefly, 24 Japanese white rabbits were anesthetized and intubated. Normal saline was instilled into the lung and washed mildly. After instillation, rabbits were ventilated at definite settings at a total duration of 3hours. OES and HI were performed every 15minutes from the beginning of the protocol. Key findings:Here, we show that both circulatory and pulmonary ET-1 levels increased in models with lung injury induced by saline lavage compared to healthy control group. No further aggravation in expression of pulmonary ET-1 was seen after OES and HI, although OES and HI worsened arterial hypoxygenation and severity of lung injury. In contrast, circulatory ET-1 levels significantly decreased after OES and HI but were not associated with blood pressure changes. Significance:We conclude that in a saline lavage-induced lung injury model, both circulatory and pulmonary ET-1 levels increased. Further, OES and HI exerted differential effects on ET-1 expression at both circulatory and pulmonary levels.

Janus Faces of Amyloid Proteins in Neuroinflammation

Amyloid forming molecules are generally considered harmful. In Alzheimer's Disease two amyloid molecules Aβ A4 and tau vie for consideration as the main pathogenic culprit. But molecules obey the laws of chemistry and defy the way we categorize them as humans with our well-known proclivities to bias in our reasoning. We have been exploring the brains of multiple sclerosis patients to identify molecules that are associated with protection from inflammation and degeneration. In 2001 we noted that aB crystallin (cryab) was the most abundant transcript found in MS lesions, but not in healthy brains. Cryab can reverse paralysis and attenuate inflammation in several models of inflammation including experimental autoimmune encephalomyelitis (EAE), and various models of ischemia. Cryab is an amyloid forming molecule. We have identified a core structure common to many amyloids including amyloid protein Aβ A4, tau, amylin, prion protein, serum amyloid protein P, and cryab. The core hexapeptide structure is highly immune suppressive and can reverse paralysis in EAE when administered systemically. Administration of this amyloid forming hexapeptide quickly lowers inflammatory cytokines in plasma like IL-6 and IL-2. The hexapeptide bind a set of proinflammatory mediators in plasma, including acute phase reactants and complement components. The beneficial properties of amyloid forming hexapeptides provide a potential new therapeutic direction. These experiments indicate that amyloid forming molecules have Janus faces, providing unexpected benefit for neuroinflammatory conditions.

Maternal Dietary Docosahexaenoic Acid Supplementation Attenuates Fetal Growth Restriction and Enhances Pulmonary Function in a Newborn Mouse Model of Perinatal Inflammation1–3

The preterm infant is often exposed to maternal and neonatal inflammatory stimuli and is born with immature lungs, resulting in a need for oxygen therapy. Nutritional intervention with docosahexaenoic acid (DHA; 6.3 g/kg of diet) has been shown to attenuate inflammation in various human diseases. Previous studies demonstrated that maternal DHA supplementation during late gestation and lactation attenuated hyperoxic lung injury in newborn mouse pups. In the present studies, we tested the hypothesis that DHA supplementation to the dam would reduce hyperoxic lung injury and growth deficits in a more severe model of systemic maternal inflammation, including lipopolysaccharide (LPS) and neonatal hyperoxia exposure. On embryonic day 16, dams were placed on DHA (6.3 g DHA/kg diet) or control diets and injected with saline or LPS. Diets were maintained through weaning. At birth, pups were placed in room air or hyperoxia for 14 d. Improvements in birth weight (P < 0.01), alveolarization (P ≤ 0.01), and pulmonary function (P ≤ 0.03) at 2 and 8 wk of age were observed in pups exposed to perinatal inflammation and born to DHA-supplemented dams compared with control diet–exposed pups. These improvements were associated with decreases in tissue macrophage numbers (P < 0.01), monocyte chemoattractant protein-1 expression (P ≤ 0.05), and decreases in soluble receptor for advanced glycation end products concentrations (P < 0.01) at 2 and 8 wk. Furthermore, DHA supplementation attenuated pulmonary fibrosis, which was associated with the reduction of matrix metalloproteinases 2, 3, and 8 (P ≤ 0.03) and collagen mRNA (P ≤ 0.05), and decreased collagen (P < 0.01) and vimentin (P ≤ 0.03) protein concentrations. In a model of severe inflammation, maternal DHA supplementation lessened inflammation and improved lung growth in the offspring. Maternal supplementation with DHA may be a therapeutic strategy to reduce neonatal inflammation.

Abstract 207: Angiotensin 1-7 Reduces Mortality and Aneurysm Rupture in a Mouse Model of Intracranial Aneurysms

Inflammation has been linked to progression and rupture of intracranial aneurysms in humans and animal models. Angiotensin II drives vascular inflammation in several models of vascular disease. Angiotensin 1-7, the product of metabolism of angiotensin II by ACE2, acts on Mas receptors and counteracts the deleterious effects of angiotensin II. We previously demonstrated that ACE2 deficiency is associated with cerebrovascular dysfunction. We now explore the hypothesis that angiotensin 1-7 attenuates formation and rupture of intracranial aneurysms in mice. In wild type (WT) C57Bl/6 mice an intracranial injection of elastase was made, and then angiotensin II (Ang II) or angiotensin II + angiotensin 1-7 (Ang II + Ang 1-7) were infused for 3 weeks. Increase in systolic pressure was similar in mice receiving Ang II (146±5 mmHg, mean ±SE) or Ang II + Ang 1-7 (147±5 mmHg). Mortality was higher in Ang II-treated mice (64% (16/25)) than in Ang II + Ang 1-7-infused mice (33% (7/21) p&lt;0.05). Aneurysm formation was similar in both groups (88% (22/25) Ang II vs. 81% (17/21) Ang II + ang 1-7). Incidence of subarachnoid hemorrhage (SAH) was lower (43% (9/21)) in Ang II + Ang 1-7 than in Ang II treated mice (68% (17/25), p&lt;0.05). Similar studies were performed in Mas receptor knockout mice (Mas-KO). Increase in systolic pressure was similar (136±4 vs. 137±8 mmHg) in Mas-KO mice that received Ang II or Ang II + Ang 1-7 respectively. There was no significant difference in aneurysm formation (83% 10/12 vs. 100% 14/14) or SAH incidence (50% 6/12 vs. 64% 9/14) in Mas-KO mice treated with Ang II or Ang II + Ang 1-7 respectively (p&gt;0.05). In conclusion, angiotensin 1-7 does not attenuate the increase in systolic blood pressure induced by Ang II in WT or Mas-KO mice. Angiotensin 1-7 does not affect the incidence of aneurysm formation in this mouse model of intracranial aneurysms. Importantly, angiotensin 1-7 decreases mortality and intracranial aneurysm rupture. Protective effects of angiotensin 1-7 on aneurysm rupture are not seen in Mas-KO mice, confirming that these effects of angiotensin 1-7 are mediated by its receptor Mas. We speculate that angiotensin 1-7 may be of therapeutic value for prevention of rupture of intracranial aneurysms.

Role of glucose-dependent insulinotropic polypeptide in adipose tissue inflammation of dipeptidylpeptidase 4-deficient rats

Dipeptidyl peptidase 4 (DPP4) inhibitors, used in obese diabetic patients, reduce inflammation in several models. The role of chronic DPP4-deficiency (DPP4-) in diet-induced obesity with respect to insulin sensitivity and adipose tissue inflammation was investigated. Insulin resistance was induced by 2 months high fat diet (HFD). In vitro effects of glucose-dependent insulinotropic polypeptide (GIP) were assessed in adipose tissue explants and stromal vascular fraction (SVF). HFD-fed DPP4-rats gained significantly more weight and visceral fat mass, yet were more insulin sensitive. Adipose tissue of DPP4- rats demonstrated increased adipocyte maturation and increased expression of enzymes involved in triglyceride uptake and synthesis, yet increased adiponectin mRNA, reduced mRNA of proinflammatory cytokines and reduced vascular adhesion molecules, suggesting reduced inflammation. In vitro and in vivo experiments explored the role of GIP in inducing this phenotype. Indeed, we demonstrated that GIP directly enhanced adiponectin expression in rat and human adipose tissue explants and in SVF. Lastly, GIP administration to normal or HFD-fed rats elevated serum adiponectin and improved their glucose tolerance test. In a HFD model, DPP4-rats exhibited reduced adipose tissue inflammation and improved insulin resistance, which may be mediated in part by GIP induction of adiponectin.

Pancreatic islet xenograft survival in mice is extended by a combination of alpha-1-antitrypsin and single-dose anti-CD4/CD8 therapy.

Clinical pancreatic islet transplantation is under evaluation for the treatment of autoimmune diabetes, yet several limitations preclude widespread use. For example, there is a critical shortage of human pancreas donors. Xenotransplantation may solve this problem, yet it evokes a rigorous immune response which can lead to graft rejection. Alpha-1-antitrypsin (AAT), a clinically available and safe circulating anti-inflammatory and tissue protective glycoprotein, facilitates islet alloimmune-tolerance and protects from inflammation in several models. Here, we examine whether human AAT (hAAT), alone or in combination with clinically relevant approaches, achieves long-term islet xenograft survival. Rat-to-mouse islet transplantation was examined in the following groups: untreated (n = 6), hAAT (n = 6, 60–240 mg/kg every 3 days from day −10), low-dose co-stimulation blockade (anti-CD154/LFA-1) and single-dose anti-CD4/CD8 (n = 5–7), either as mono- or combination therapies. Islet grafting was accompanied by blood glucose follow-up. In addition, skin xenografting was performed in order to depict responses that occur in draining lymph nodes. According to our results hAAT monotherapy and hAAT/anti-CD154/LFA-1 combined therapy, did not delay rejection day (11–24 days untreated vs. 10–22 day treated). However, host and donor intragraft inflammatory gene expression was diminished by hAAT therapy in both setups. Single dose T-cell depletion using anti-CD4/CD8 depleting antibodies, which provided 14–15 days of reduced circulating T-cells, significantly delayed rejection day (28–52 days) but did not achieve graft acceptance. In contrast, in combination with hAAT, the group displayed significantly extended rejection days and a high rate of graft acceptance (59, 61, >90, >90, >90). In examination of graft explants, marginal mononuclear-cell infiltration containing regulatory T-cells predominated surviving xenografts. We suggest that temporal T-cell depletion, as in the clinically practiced anti-thymocyte-globulin therapy, combined with hAAT, may promote islet xenograft acceptance. Further studies are required to elucidate the mechanism behind the observed synergy, as well as the applicability of the approach for pig-to-human islet xenotransplantation.