Active resolution of acute inflammation is a previously unrecognized interface between innate and adaptive immunity. Once thought to be a passive process, the resolution of inflammation is now shown to involve active biochemical programmes that enable inflamed tissues to return to homeostasis. This Review presents new cellular and molecular mechanisms for the resolution of inflammation, revealing key roles for eicosanoids, such as lipoxins, and recently discovered families of endogenous chemical mediators, termed resolvins and protectins. These mediators have anti-inflammatory and pro-resolution properties, thereby protecting organs from collateral damage, stimulating the clearance of inflammatory debris and promoting mucosal antimicrobial defence.

Resolving inflammation : dual anti-inflammatory and pro-resolution lipid mediators

1. Type 1 diabetes (due to b-cell destruction, usually leading to absolute insulin deficiency) 2. Type 2 diabetes (due to a progressive insulin secretory defect on the background of insulin resistance) 3. Gestational diabetes mellitus (GDM) (diabetes diagnosed in the second or third trimester of pregnancy that is not clearly overt diabetes) 4. Specific types of diabetes due to other causes, e.g., monogenic diabetes syndromes (such as neonatal diabetes and maturity-onset diabetes of the young [MODY]), diseases of the exocrine pancreas (such as cystic fibrosis), and drugor chemical-induced diabetes (such as in the treatment of HIV/AIDS or after organ transplantation)

Classification and diagnosis of diabetes

Advances in our understanding of the mechanisms that bring about the resolution of acute inflammation have uncovered a new genus of pro-resolving lipid mediators that include the lipoxin, resolvin, protectin and maresin families, collectively called specialized pro-resolving mediators. Synthetic versions of these mediators have potent bioactions when administered in vivo. In animal experiments, the mediators evoke anti-inflammatory and novel pro-resolving mechanisms, and enhance microbial clearance. Although they have been identified in inflammation resolution, specialized pro-resolving mediators are conserved structures that also function in host defence, pain, organ protection and tissue remodelling. This Review covers the mechanisms of specialized pro-resolving mediators and omega-3 essential fatty acid pathways that could help us to understand their physiological functions.

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Pro-resolving lipid mediators are leads for resolution physiology

Dysfunction of the endothelial lining of lesion-prone areas of the arterial vasculature is an important contributor to the pathobiology of atherosclerotic cardiovascular disease. Endothelial cell dysfunction, in its broadest sense, encompasses a constellation of various nonadaptive alterations in functional phenotype, which have important implications for the regulation of hemostasis and thrombosis, local vascular tone and redox balance, and the orchestration of acute and chronic inflammatory reactions within the arterial wall. In this review, we trace the evolution of the concept of endothelial cell dysfunction, focusing on recent insights into the cellular and molecular mechanisms that underlie its pivotal roles in atherosclerotic lesion initiation and progression; explore its relationship to classic, as well as more recently defined, clinical risk factors for atherosclerotic cardiovascular disease; consider current approaches to the clinical assessment of endothelial cell dysfunction; and outline some promising new directions for its early detection and treatment.

Endothelial Cell Dysfunction and the Pathobiology of Atherosclerosis

We introduce a methodology to assess differential abundance in sparse high-throughput microbial marker-gene survey data. Our approach, implemented in the metagenomeSeq Bioconductor package, relies on a novel normalization technique and a statistical model that accounts for undersampling-a common feature of large-scale marker-gene studies. Using simulated data and several published microbiota data sets, we show that metagenomeSeq outperforms the tools currently used in this field.

Differential abundance analysis for microbial marker-gene surveys

Translation of experimental data to the clinical setting requires the safety and efficacy of such data to be confirmed in animal systems before application in humans. In dental research, the animal species used is dependent largely on the research question or on the disease model. Periodontal disease and, by analogy, peri-implant disease, are complex infections that result in a tissue-degrading inflammatory response. It is impossible to explore the complex pathogenesis of periodontitis or peri-implantitis using only reductionist in-vitro methods. Both the disease process and healing of the periodontal and peri-implant tissues can be studied in animals. Regeneration (after periodontal surgery), in response to various biologic materials with potential for tissue engineering, is a continuous process involving various types of tissue, including epithelia, connective tissues and alveolar bone. The same principles apply to peri-implant healing. Given the complexity of the biology, animal models are necessary and serve as the standard for successful translation of regenerative materials and dental implants to the clinical setting. Smaller species of animal are more convenient for disease-associated research, whereas larger animals are more appropriate for studies that target tissue healing as the anatomy of larger animals more closely resembles human dento-alveolar architecture. This review focuses on the animal models available for the study of regeneration in periodontal research and implantology; the advantages and disadvantages of each animal model; the interpretation of data acquired; and future perspectives of animal research, with a discussion of possible nonanimal alternatives. Power calculations in such studies are crucial in order to use a sample size that is large enough to generate statistically useful data, whilst, at the same time, small enough to prevent the unnecessary use of animals.

Animal models for periodontal regeneration and peri‐implant responses

/pdf/platelet-rich-plasma-growth-factors-and-pro-and-anti-40zoqblo6n.pdf

Platelet-Rich Plasma: Growth Factors and Pro- and Anti-Inflammatory

Epithelial to mesenchymal transition (EMT) occurs normally in development. In pathology, EMT drives cancer and fibrosis. Medication with phenytoin, nifedipine, and cyclosporine-A often causes gingival overgrowth. Based partly on the histopathology of gingival overgrowth, the present study investigates the hypothesis that EMT could contribute to its development. We found that phenytoin-induced human gingival overgrowth tissues, the most fibrotic drug-induced variety, contain diminished epithelial E-cadherin expression, whereas fibroblast-specific protein-1 (FSP-1) and αvβ6 integrin levels are up-regulated. In connective tissue stroma, fibronectin and alternatively spliced fibronectin extra type III domain A (FN-ED-A) levels are increased in overgrowth lesions. Transforming growth factor (TGF)-β1 treatment of primary human gingival epithelial cells cultured in transwell plates resulted in inhibited barrier function as determined by reduced electrical resistance, paracellular permeability assays, and cell surface E-cadherin expression. Moreover, TGF-β1 altered the expression of other markers of EMT determined at the mRNA and protein levels: E-cadherin decreased, whereas SLUG, fibronectin, matrix metalloproteinase (MMP)2, MMP9, and MMP13 increased. Nifedipine- and cyclosporine A–induced gingival overgrowth tissues similarly contain diminished E-cadherin and elevated levels of FSP-1 and fibronectin, but normal levels of αvβ6 integrin. In summary, data in vitro support that human gingival epithelial cells undergo functional and gene expression changes consistent with EMT in response to TGF-β1, and in vivo studies show that important EMT markers occur in clinical gingival overgrowth tissues. These findings support the hypothesis that EMT likely occurs in drug-induced gingival overgrowth.

Epithelial to Mesenchymal Transition in Gingival Overgrowth

Oxidative stress has been found to play a role in the pathogenesis of diabetic complica- tions. The aim of this study was to define the oxi- dative burst of diabetic monocytes to characterize the phenotype associated with poor diabetic con- trol. Superoxide (O2 - ) is the first molecule gener- ated during the respiratory burst of phagocytes by NADPH oxidase, and its generation by monocytes from 26 controls and 34 diabetic subjects was evaluated in this study. Under resting states or stimulation by PMA or opsonized zymosan, dia- betic monocytes produce significantly more O2 - than nondiabetic cells. The increased O2 - genera- tion was found to be correlated with glycemic con- trol (glycated hemoglobin) of patients. To clarify the effects of hyperglycemia on O2 - generation, normal human monocytes were treated with recep- tor for advanced glycation endproducts (RAGE) ligands (AGE protein and S100B) or high glucose media before stimulation. RAGE ligands and high glucose concentration increased O2 - generation from human mononuclear phagocytes. RAGE li- gands, specifically and potently, increased O2 - gen- eration from mononuclear phagocytes, and high- glucose effects were associated with correspond- ingly increased osmotic pressure. Differentiated THP-1 cells, from a human monocytic cell line, were used as a model of human monocytes to study the effects of S100B, the RAGE ligand. It was confirmed that RAGE is involved in the priming of O2 - generation by S100B. This study demonstrates that RAGE ligands can contribute significantly to the hyper-responsive phenotype of diabetic mono- cytes, which might be reversible by blocking the RAGE or controlling the presence of RAGE ligands by controlling hyperglycemia. J. Leukoc. Biol. 81: 000-000; 2007.

https://jlb.onlinelibrary.wiley.com/doi/pdf/10.1189/jlb.0406262

Activation of RAGE induces elevated O2- generation by mononuclear phagocytes in diabetes

Diabetic complications involve inflammation-mediated microvascular and macrovascular damage, disruption of lipid metabolism, glycosylation of proteins, and abnormalities of neutrophil-mediated events. Resolution of inflamed tissues to health and homeostasis is an active process mediated by endogenous lipid agonists, including lipoxins and resolvins. This proresolution system appears to be compromised in type 2 diabetes (T2D). The goal of this study was to investigate unresolved inflammation in T2D. Wild-type (WT) and genetically engineered mice, including T2D mice (db/db), transgenic mice overexpressing the human resolvin E1 (RvE1) receptor (ERV1), and a newly bred strain of db/ERV1 mice, were used to determine the impact of RvE1 on the phagocytosis of Porphyromonas gingivalis in T2D. Neutrophils were isolated and incubated with fluorescein isothiocyanate-labeled P. gingivalis, and phagocytosis was measured in a fluorochrome-based assay by flow cytometry. Mitogen-activated protein kinase (MAPK) (p42 and p44) and Akt (Thr308 and Ser473) phosphorylation was analyzed by Western blotting. The mouse dorsal air pouch model was used to evaluate the in vivo impact of RvE1. Results revealed that RvE1 increased the neutrophil phagocytosis of P. gingivalis in WT animals but had no impact in db/db animals. In ERV1-transgenic and ERV1-transgenic diabetic mice, phagocytosis was significantly increased. RvE1 decreased Akt and MAPK phosphorylation in the transgenic animals. In vivo dorsal air pouch studies revealed that RvE1 decreases neutrophil influx into the pouch and increases neutrophil phagocytosis of P. gingivalis in the transgenic animals; cutaneous fat deposition was reduced, as was macrophage infiltration. The results suggest that RvE1 rescues impaired neutrophil phagocytosis in obese T2D mice overexpressing ERV1.

https://iai.asm.org/content/iai/83/2/792.full.pdf

Hatice Hasturk

Papers

Animal models for periodontal regeneration and peri‐implant responses

Platelet-Rich Plasma: Growth Factors and Pro- and Anti-Inflammatory

Epithelial to Mesenchymal Transition in Gingival Overgrowth

Activation of RAGE induces elevated O2- generation by mononuclear phagocytes in diabetes

Impact of Resolvin E1 on Murine Neutrophil Phagocytosis in Type 2 Diabetes