Modulation by lymphocytes of the vascular effects caused by inflammatory mediators and carrageenin in the rat.

Inhibited permeability responses to intradermally injected histamine, serotonin and bradykinin were observed in leucopenic rats, when compared to those measured in normal animals. Significant reversal of the inhibited responses was seen when leucopenic rats were given suspensions of lymphocytes i.v. Suspensions of PMN granulocytes, however, were ineffective. In both cases, the volumes of the suspensions contained adequate quantities of the particular cells to counteract their deficiency. Histological changes provoked by carrageenin in the paws of leucopenic rats injected with suspensions of lymphocytes resembled those of normal rats, the main difference being that the number of cells which had emigrated into the affected tissues was reduced. In leucopenic controls or leucopenic animals injected with suspensions of PMN granulocytes, minimal histological alterations were observed. It is concluded that lymphocytes play a role in the development of acute inflammatory reactions.     

Platelets,acute inflammation and inflammatory mediators

The anti-inflammatory activity of aspirin-like drugs could derive, at least in part, by inhibiting synthesis and release of prostaglandins or rabbit aorta-contracting substance from platelets. Indeed, aggregation of platelets and the consequent release of inflammatory mediators has been frequently evoked as a factor in the development of the inflammatory reaction. The participation of platelets in acute inflammation was tested in three types of trauma in rats rendered thrombocytopenic with anti-platelet serum. Oedema in response to carrageenin, anti-platelet serum or passive cutaneous anaphylaxis was no different from the controls in thrombocytopenic rats.     

Modulation of leukotaxis by ibuprofen

The purpose of this study was to evaluate the rabbit anterior eye chamber as a quantitative measure of leukotaxis using⁵¹Cr-labeled homologous leukocytes and then to determine the effects of ibuprofen onN-formyl-methionyl-leucyl-phenylalanine (FMLP) -induced leukotaxis. Leukocyte accumulation was assessed at various intervals (0–24 h) after instillation of FMLP (10^–4 M, 40l) and at various doses (FMLP 10^–6–10^–4 M). New Zealand white rabbits (2.6–3.0 kg) were treated with ibuprofen for three days with the following regimens: 8.0, 17.5, 35.0, 70.0 mg/kg/day. Leukocyte quantitation was determined using a direct cell count and recovery of⁵¹Cr-labeled leukocytes from anterior eye chamber aspirations 3 h after their injection into the systemic circulation. FMLP induced a dose-dependent accumulation of leukocytes. Leukocyte influx into the anterior eye chamber increased between 2 and 4 h after FMLP instillation, peaking between 4 and 6 h, then resolving after 8 h. Ibuprofen inhibited leukocyte accumulation into the anterior eye chamber in a dose dependent fashion with a maximum (90.0±1.4%, X±SEM) inhibition with 70 mg/kg/day and an ID₅₀ of 8 mg/kg/day. In conclusion, the anterior eye chamber FMLP-stimulated leukotaxis assay is useful to evaluate the role of pharmacologie agents. Here, ibuprofen was found to inhibit leukotaxis in a dose-dependent manner.This project was supported in part by NIH grant HD-19002 and an award from the USC Faculty Research and Innovation Fund.     

Differentiation of chronic sinus diseases by measurement of inflammatory mediators

Background:  Chronic rhinosinusitis (CRS) clinically is a heterogeneous group of sinus diseases, which may cover different disease entities, or may represent a disease continuum. Studying inflammatory cells and mediators in clearly defined disease subgroups may lead to a better differentiation of chronic sinus diseases.
Methods:  Sinonasal mucosal tissue from 10 nasal polyp (NP) patients, 13 cystic fibrosis patients (CF-NP), eight CRS subjects without polyps, and nine control patients were stained for CD3, CD25, CD68, CD20, myeloperoxidase (MPO), CD138 and tissue homogenates were assayed for eotaxin, interleukin (IL)-1 β , IL-2sR α , IL-5, interferon (IFN)- γ , IL-8, transforming growth factor (TGF)- β 1, tumor necrosis factor- α , and MPO by enzyme-linked immunosorbent assay or UNICAP system.
Results:  Nasal polyp and CF-NP showed increased numbers and activation of T cells, while only NP displayed an increase in plasma cells. Nasal polyp had significantly higher levels of eosinophilic markers [eosinophils, eotaxin, and eosinophil cationic protein (ECP)] compared with CRS, controls and CF-NP. Chronic rhinosinusitis was characterized by a Th1 polarization with high levels of IFN- γ and TGF- β , while NP showed a Th2 polarization with high IL-5 and immunoglobulin (Ig) E concentrations. Nasal polyp and CF-NP were discriminated by edema from CRS and controls, with CF-NP displaying a very prominent neutrophilic inflammation.
Conclusion:  Based on cellular and mediator profiles, we suggest that CRS, NP, and CF-NP are distinct disease entities within the group of chronic sinus diseases.     

Mast cells and inflammatory mediators in chronic ulcerative colitis

Chronic ulcerative colitis (CUC) is an inflammatory destructive disease of the large intestine characterized by motility and secretion disorders. In the past decade, attention has been paid to the role of neuronal structures and mast cells in regulating inflammatory and immune responses in inflammatory bowel disease (IBD). The present study was performed to demonstrate neuronal fibres (NF) and cells containing substance P (SP), tryptase and serotonin (SER) in the colonic wall of patients with CUC in remission. Biopsy specimens of 6 patients with CUC were investigated with immunocytochemical methods. Normal colon tissue obtained from 6 patients with rectal carcinoma was used as a control. An increased number of SP- and SER-positive NF was found in all the layers of the intestinal wall. The number of SER-containing endocrine cells in the mucosal glands was also increased per crypt. Tryptase-, SP- and SER-immunopositive mast cells were found in higher amounts than in control specimens in close apposition to the basal lamina of the glands among the epithelial cells and in other layers of the gut wall. Two types of mast cells were found: mast cells containing both tryptase and SP, and mast cells containing tryptase only. It is concluded that interactions between neuronal elements and mast cells play a significant role in the progress and maintenance of inflammatory processes in CUC.     

Release of inflammatory mediators by adipose tissue during acute pancreatitis

Obesity and lipid metabolism are associated with the severity of acute pancreatitis. Fat necrosis appears in the severe acute pancreatitis as a consequence of the release of lipolytic enzymes, but its potential role on the progression of the disease is unclear. In this study, we have examined the role of white adipose tissue as a source of inflammatory mediators that can promote systemic inflammation during experimental taurocholate‐induced acute pancreatitis in rats. The inflammatory status and the expression of TNFα, iNOS, adiponectin and IL‐10 were determined in necrotic and non‐necrotic areas of adipose tissue. Samples of adipose tissue were also used to induce the activation of macrophages in vitro. Finally, the release of TNFα to mesenterial vessels surrounded by necrotic or non‐necrotic fat was evaluated in ex vivo perfused mesenterium. A strong inflammatory infiltrate was observed in the border between necrotic and non‐necrotic areas of adipose tissue. In these areas, high expression of TNFα and iNOS and a reduced expression of IL‐10 were observed, while adiponectin showed only a moderate increase. Necrotic fat strongly activates peritoneal macrophages in vitro. Mesenterial areas with fat necrosis release to the vascular vessels significantly increased amounts of TNFα when compared to vessels without necrosis. Altogether, these results indicate that adipose tissue inflammation is a process secondary to acute pancreatitis but also contributes to the generation of mediators potentially involved in the induction of the systemic inflammatory response. In particular, the areas of fat necrosis are important sources of inflammatory mediators. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Modulation of the receptor for urokinase-type plasminogen activator in macrophage-like U937 cells by inflammatory mediators

Macrophages in the tissues have been shown to express receptor for urokinase-type plasminogen activator (uPAR) on their cell surface which plays an important role in cell invasion and attachment. We examined the effects of inflammatory mediators on the expression of uPAR employing U937 cells which have monocyte/ macrophage-like characteristics. U937 cells were incubated with various mediators such as interleukins (IL), tumor necrosis factors (TNF), dexamethasone, thrombin, fibrin fragment D, bradykinin, complement C5a, and components of the extracellular matrix. The uPAR expression on the cell surface was then analyzed by radio-ligand binding assay using¹²⁵I-scuPA. The strongest enhancement of uPAR was observed in the cells stimulated by TNF and TNF. IL-1, IL-6, and C5a also increased the uPA binding sites with various patterns of affinity change. Dexamethasone decreased the uPA binding sites without changing the affinity. Fibrin fragment D and IL-3 reduced the affinity without changing the number of receptors. These findings suggest that the expression of uPAR in inflammatory cells could be modulated by various inflammatory mediators.     

Desensitization of cold- and menthol-sensitive rat dorsal root ganglion neurones by inflammatory mediators

The interaction between cold sensitivity and inflammation in mammals is not entirely understood. We have used adult rat dorsal root ganglion neurones in primary culture together with calcium microfluorimetry to assess the effects of selected inflammatory mediators on cold responses of cold- and menthol-sensitive (most likely TRPM8-expressing) neurones. We observed a high degree of functional co-expression of TRPM8, the receptors for the inflammatory agents bradykinin, prostaglandin E₂ and histamine, and TRPA1 in cultured sensory neurones. Treatment with either bradykinin or prostaglandin E₂ led to a reduction in the amplitude of the response to cooling and shifted the threshold temperature to colder values, and we provide evidence for a role of protein kinases C and A, respectively, in mediating these effects. In both cases the effects were mainly restricted to the subgroups of cold- and menthol-sensitive cells which had responded to the application of the inflammatory agents at basal temperature. This desensitization of cold-sensitive neurones may enhance inflammatory pain by removing the analgesic effects of gentle cooling.     

Modulation of angiogenesis in a model of chronic inflammation

Inflammation Research -     

Nasal physiology and inflammatory mediators during natural pollen exposure

Nasal allergen challenges in allergic rhinitis subjects provoke characteristic alterations in nasal and eustachian tube (ET) function. The purpose of this study was to examine the effect of natural pollen exposure on nasal physiology and inflammatory mediators. Grass pollen counts, ET function (sonotubometry), nasal resistance (rhinomanometry), symptoms, mediator levels (saline wash), and skin test reactivity in nine adults with grass allergy were monitored weekly before (week 1), during (weeks 2 to 9) and after (weeks 10 and 11) grass pollen season. Pollen counts peaked at week 3, and then decreased gradually. Mean nasal resistance (cm H2O/L/sec) increased from a baseline of 2.4 +/- 0.5 to 3.7 +/- 1.1 at week 3, peaked at week 4 (5.3 +/- 1.2), remained elevated (weeks 5-8), peaked again at week 9 (6.6 +/- 1.4), and then decreased, Bilateral ET obstruction was not present in any of the subjects at baseline, but was present in five of the nine subjects at week 4. Symptom severity paralleled grass pollen counts. Peak mediator levels were observed at weeks 2 and 9 for histamine and at weeks 3 and 10 for leukotriene C4. Seasonal increases in grass and histamine-induced wheal sizes were also observed. These data show that measurable changes in the function of the nose and ET and the levels of nasal mediators and dermal reactivity accompany and track pollen counts during seasonal exposure and suggest that therapy for seasonal allergic rhinitis should be (1) directed at reducing airway inflammation and (2) continued well beyond the time of peak pollen exposure.     

The epithelium-derived inflammatory mediators of chronic rhinosinusitis with nasal polyps

ABSTRACT

Introduction: Chronic rhinosinusitis with nasal polyps (CRSwNP) is an inflammatory airway disease characterized as tight junction loosening, inflammation, and mucosal remodeling. Epithelial cells form a barrier against allergens, bacteria, and proteases, and can also trigger or enhance the immune response by releasing various inflammatory mediators including cytokines, chemokines, and secreted proteins to promote the pathogenesis of CRSwNP.

Areas covered: We review the epithelium-derived cytokine and secreted protein networks driving CRSwNP, and discuss these mediators in a cellular context. We illustrate their roles as potential mediators-biomarkers in clinical practice, which may help to understand the mechanisms underlying the pathologies of different endotypes of CRSwNP and to improve treatment outcomes in patients with CRSwNP based on the development of novel predictors for CRSwNP management.

Expert opinion: The understanding of the role of epithelium-derived inflammatory mediators helps to investigate the pathophysiological mechanisms of CRSwNP endotypes. An increasing number of studies show that these mediators target immune cells and promote the recruitment, activation or regulation of the proliferation or apoptosis of these cells. Based on this achievement, further investigations are necessary to explore the multi-dimensional role of epithelium-derived inflammatory mediators in CRSwNP.     

Consequences of intestinal inflammation on the enteric nervous system: neuronal activation induced by inflammatory mediators

The ENS is responsible for the regulation and control of all gastrointestinal functions. Because of this critical role, and probably as a consequence of its remarkable plasticity, the ENS is often relatively well preserved in conditions where the architecture of the intestine is seriously disrupted, such as in IBD. There are structural and functional changes in the enteric innervation in animal models of experimental intestinal inflammation and in IBD. These include both up and down regulation of transmitter expression and the induction of new genes in enteric neurons. Using Fos expression as a surrogate marker of neuronal activation it is now well established that enteric neurons (and also enteric glia) respond to inflammation. Whether this "activation" is limited to a short-term functional response, such as increased neuronal excitability, or reflects a long-term change in some aspect of the neuronal phenotype (or both) has yet to be firmly established, but it appears that enteric neurons are highly plastic in their response to inflammation.     

Indirect evidence of bronchial inflammation assessed by titration of inflammatory mediators in BAL fluid of patients with asthma

Bronchial inflammation is a characteristic of asthma that may be examined indirectly by bronchoalveolar lavage (BAL). Nine normal individuals were compared with 38 age-matched adults with asthma of variable severity to appreciate the importance of cell activation in the severity of asthma. The severity of asthma was appreciated by the clinical score of Aas and the pulmonary function of the patients. FEV1 ranged between 35% and 130% of predicted. The indirect activation of eosinophils (EOSs), mast cells, fibroblasts, and neutrophils was examined by the titration of eosinophil cationic protein (ECP), tryptase, hyaluronan (HA), and myeloperoxidase (MPO) by radioimmunoassay in BAL fluid (BALF) and cytology of BALF. In the adults with asthma, there was a significantly increased number of EOSs and a significantly increased level of all mediators but MPO. MPO levels were increased in seven patients only; three of these patients were previous smokers. Only ECP and HA levels were significantly correlated with the severity of asthma. These results demonstrate EOSs, mast cells, and fibroblasts are activated in asthma, whereas the involvement of neutrophils is less clear. There was a significant correlation between ECP and HA levels, suggesting a common activation of EOSs and fibroblasts.     

Annexin A1 based inflammation resolving mediators and nanomedicines for inflammatory bowel disease therapy

Inflammatory bowel diseases (IBD) such as Crohn’s Disease (CD) and Ulcerative Colitis (UC) are chronic, progressive, and relapsing disorders of the gastrointestinal tract (GIT), characterised by intestinal epithelial injury and inflammation. Current research shows that in addition to traditional anti-inflammatory therapy, resolution of inflammation and repair of the epithelial barrier are key biological requirements in combating IBD. Resolution mediators include endogenous lipids that are generated during inflammation, e.g., lipoxins, resolvins, protectins, maresins; and proteins such as Annexin A1 (ANXA1). Nanoparticles can specifically deliver these potent inflammation resolving mediators in a spatiotemporal manner to IBD lesions, effectively resolve inflammation, and promote a return to homoeostasis with minimal collateral damage. We discuss these exciting and timely concepts in this review.     

Gaseous mediators in resolution of inflammation

There are numerous gaseous substances that can act as signaling molecules, but the best characterized of these are nitric oxide, hydrogen sulfide and carbon monoxide. Each has been shown to play important roles in many physiological and pathophysiological processes. This article is focused on the effects of these gasotransmitters in the context of inflammation. There is considerable overlap in the actions of nitric oxide, hydrogen sulfide and carbon monoxide with respect to inflammation, and these mediators appear to act primarily as anti-inflammatory substances, promoting resolution of inflammatory processes. They also have protective and pro-healing effects in some tissues, such as the gastrointestinal tract and lung. Over the past two decades, significant progress has been made in the development of novel anti-inflammatory and cytoprotective drugs that release of one or more of these gaseous mediators.     

Regulation of immunity and inflammation by mediators from macrophages.

Mononuclear phagocytes secrete a number of materials into the extracellular environment. The materials secreted by phagocytes can be grouped into three categories: a) enzymes affecting extracellular proteins (collagenase, elastase, lysosomal proteases, plasminogen activators), b) materials involved in defense processes (complement proteins, interferons, lysozyme), and c) factors regulating activities of surrounding cells. The latter include lymphostimulatory molecules, a colony-stimulating factor, and inhibitors of cell growth. The conditions for secretion of the materials depend on the activity of the phagocytes. The lymphostimulatory molecules secreted by macrophages exert various effects: 1) an increase in DNA synthesis of lymphocytes, 2) a maturation of early thymocytes to mature T cells, and 3) the differentiation of some B cells to antibody-secreting cells. The mitogenic principle has been partially isolated as a protein of 15,000 to 20,000 daltons. The secretion of lymphostimulatory molecules is increased following uptake of various materials by macrophages or by addition of activated T cells to macrophage cultures.