Topical glucocorticoids inhibit neurogenic inflammation: involvement of lipocortin 1

Antibacterial drugs in the form of sprays for the topical treatment of pyodermas and dermatoses complicated with a secondary infection

The article covers issues related to the application of topical antibacterial drugs for the treatment of pyodermic skin diseases. The author describes mechanisms of action and advantages of the topical form of antibiotics and GCS for the topical treatment of pyodermas. The article substantiates indications for the administration of topical GCS drugs in a combination with antibacterial drugs. The efficacy and safety of antibacterial and combination topical drugs such as Neomycin, Oxycort and Polcortolon TC in the form sprays for the treatment of pyodermas and complicated forms of chronic dermatosis.

Prophylactic proopiomelanocortin expression alleviates capsaicin-induced neurogenic inflammation in rat trachea

Neurogenic inflammation frequently causes acute plasma leakage in airways and life-threatening pulmonary edema. However, limited strategies are available to alleviate neurogenic inflammation. Proopiomelanocortin (POMC) is the precursor of anti-inflammatory melanocortins, which have been proposed of therapeutic potential for various inflammatory diseases. The present study aimed to evaluate whether peripheral POMC expression ameliorated capsaicin-induced acute neurogenic inflammation in rat trachea. Prophylactic POMC expression was achieved by intravenous injection of adenovirus encoding POMC (Ad-POMC), which led to POMC expression in livers and elevated plasma adrenocorticotropin levels for approximately 60 days. After gene delivery for 7 days, neurogenic inflammation was induced in rats by capsaicin injection. The extent of capsaicin-evoked plasma leakage in trachea was alleviated in Ad-POMC-treated rats compared with animals of control groups (P < 0.01). Moreover, the number of endothelial gaps in tracheal venules was also significantly decreased in Ad-POMC-treated animals (P < 0.01). Prophylactic POMC expression, however, did not alter the basal substance P (SP) expression or the capsaicin-induced SP elevation in trachea and circulation. Instead, cell cultures studies revealed that POMC overexpression or application of POMC-derived melanocortins potently inhibited the SP-induced migration of endothelial cells (P < 0.01), thereby possibly contributing to the attenuation of endothelial gap formation and plasma leakage. The present study indicates that the anti-inflammatory POMC gene vector or melanocortins may constitute a therapeutic alternative for neurogenic inflammation.

Spatial expression of two anti-inflammatory mediators, annexin 1 and galectin-1, in nasal polyposis

BACKGROUND

There is renewed interest in the role played by specific counter-regulatory mechanisms to control the inflammatory host response, poorly investigated in human pathology. Here, we monitored the expression of two anti-inflammatory mediators, annexin 1 and galectin-1, and assessed their potential link to glucocorticoids' (GCs) effective control of nasal polyposis (NP).

METHODS

Total patterns of mRNA and protein expression were analysed by quantitative real-time PCR (qPCR) and Western blotting analyses, whereas ultrastructural immunocytochemistry was used for spatial localization and quantification of each mediator, focusing on mast cells, eosinophils and epithelial cells.

RESULTS

Up-regulation of the annexin 1 gene, and down-regulation of galectin-1 gene, was detected in polypoid tissue compared with nasal mucosa. Patient treatment with betamethasone augmented galectin-1 protein expression in polyps. At the cellular level, control mast cells and eosinophils displayed higher annexin 1 expression, whereas marked galectin-1 immunolabelling was detected in the granule matrix of mast cells. Cells of glandular duct epithelium also displayed expression of both annexin 1 and galectin-1, augmented after treatment.

CONCLUSION

Mast cells and epithelial cells appeared to be pivotal cell types involved in the expression of both annexin 1 and galectin-1. It is possible that annexin 1 and galectin-1 could be functionally associated with a specific mechanism in NP and that GC exert at least part of their beneficial effects on the airway mucosa by up-regulating, in a specific cell target fashion, these anti-inflammatory agonists.

Effects of the somatostatin receptor subtype 4 selective agonist J-2156 on sensory neuropeptide release and inflammatory reactions in rodents

BACKGROUND AND PURPOSE

Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive sensory nerves induce local neurogenic inflammation; somatostatin exerts systemic anti-inflammatory actions presumably via sst4/sst1 receptors. This study investigates the effects of a high affinity, sst4-selective, synthetic agonist, J-2156, on sensory neuropeptide release in vitro and inflammatory processes in vivo.

EXPERIMENTAL APPROACH

Electrically-induced SP, CGRP and somatostatin release from isolated rat tracheae was measured with radioimmunoassay. Mustard oil-induced neurogenic inflammation in rat hindpaw skin was determined by Evans blue leakage and in the mouse ear with micrometry. Dextran-, carrageenan- or bradykinin-induced non-neurogenic inflammation was examined with plethysmometry or Evans blue, respectively. Adjuvant-induced chronic arthritis was assessed by plethysmometry and histological scoring. Granulocyte accumulation was determined with myeloperoxidase assay and IL-1beta with ELISA.

KEY RESULTS

J-2156 (10-2000 nM) diminished electrically-evoked neuropeptide release in a concentration-dependent manner. EC50 for the inhibition of substance P, CGRP and somatostatin release were 11.6 nM, 14.3 nM and 110.7 nM, respectively. J-2156 (1-100 microg kg(-1) i.p.) significantly, but not dose-dependently, inhibited neurogenic and non-neurogenic acute inflammatory processes and adjuvant-induced chronic oedema and arthritic changes. Endotoxin-evoked myeloperoxidase activity and IL-1beta production in the lung, but not IL-1beta- or zymosan-induced leukocyte accumulation in the skin were significantly diminished by J-2156.

CONCLUSIONS AND IMPLICATIONS

J-2156 acting on sst4 receptors inhibits neuropeptide release, vascular components of acute inflammatory processes, endotoxin-induced granulocyte accumulation and IL-1beta synthesis in the lung and synovial and inflammatory cells in chronic arthritis. Therefore it might be a promising lead for the development of novel anti-inflammatory drugs.

Glucocorticoid inhibition of vascular abnormalities in a tibia fracture rat model of complex regional pain syndrome type I

Tibia fracture in rats evokes chronic hindpaw warmth, spontaneous extravasation, edema, allodynia, and periarticular bone loss, a syndrome resembling complex regional pain syndrome type I (CRPS I). Glucocorticoids such as methylprednisolone (MP) are probably effective analgesic and anti-edematous agents in patients suffering from CRPS and this study examined the effects of chronic MP treatment in the rat CRPS I model. Bilateral hindpaw thickness, temperature, and nociceptive thresholds were determined, and the hindlimb bone density was measured using dual-energy X-ray absorptiometry (DXA). Spontaneous cutaneous extravasation and substance P infusion evoked extravasation were determined using an Evans blue vascular permeability assay. After baseline testing, the distal tibia was fractured and the hindlimb casted for 4 weeks. At 2 weeks post-fracture MP infusion was started (1 mg/kg/day for 28 days). The rats were retested at 4, 6, and 8 weeks post-fracture. Hindpaw edema and warmth after fracture were reversed by MP infusion and these effects persisted after discontinuing treatment. Furthermore, there was an increase in spontaneous protein extravasation and an enhanced substance P evoked extravasation and edema response in the hindpaw at 4 weeks that was inhibited by MP infusion. Glucocorticoid treatment had no effect on the allodynia, hindpaw unweighting, or the periarticular bone loss observed after tibia fracture. We postulate that post-junctional facilitation of substance P signaling contributes to the hindpaw warmth, edema, and the enhanced spontaneous protein extravasation observed in this CRPS I model, and that the anti-edematous effects of glucocorticoid treatment are due to inhibition of post-junctional neuropeptide signaling.

Sexual dimorphism in the effect of nonhabituating stress on neurogenic plasma extravasation

The sympathoadrenal axis contributes to the sexual dimorphism of the inflammatory response. As stress both activates the sympathoadrenal axis and profoundly affects inflammation and inflammatory disease, we evaluated whether stress exerts a sexually dimorphic effect on a major component of the inflammatory response, plasma extravasation. We evaluated the effect of a nonhabituating stress, repeated intermittent sound (30 min/day for 4 days), on neurogenic synovial plasma extravasation, induced by bradykinin in the rat knee joint. Sound stress profoundly inhibited bradykinin-induced plasma extravasation in male rats, but profoundly enhanced it in female rats. These effects took 24 h to fully develop after the last exposure to stress. In gonadectomized males, bradykinin-induced plasma extravasation was lower than intact males, and sound stress now enhanced it, i.e. gonadectomized males were phenotypically like intact females. In gonadectomized females, bradykinin-induced plasma extravasation was greater than in intact adult females, and sound stress still enhanced it. Adrenal enucleation significantly attenuated the effect of sound stress on bradykinin-induced plasma extravasation in both male and female rats. We tested the hypothesis that these effects of sound stress were due to sustained enhanced plasma levels of stress hormones. Corticosterone and epinephrine, only when administered in combination, over five days, produced a qualitatively similar effect as sound stress, i.e. bradykinin-induced plasma extravasation was significantly decreased in males and increased in females. These findings suggest that a combined effect of the hypothalamic-pituitary adrenal and sympathoadrenal stress axes are responsible for the marked sexual dimorphism in the effect of stress on the inflammatory response.

Secretoneurin in the human aqueous humor and the absence of an effect of frequently used eye drops on the levels

Secretoneurin (SN) was detected in the aqueous humor (AH) of patients treated topically with tobramycine eye drops alone or tobramycine and cyclosporine A, tobramycine and diclofenac or tobramycine and rimexolone. The levels of the peptide were found to be higher in the uninflamed human than in the rabbit aqueous humor which may be the result of species differences and/or age-related circumstances. Furthermore, they are approximately one hundred times higher than those of classical neuropeptides indicating release from nerve fibers and/or secretion from non-pigmented ciliary epithelium cells. Despite a slight tendency by rimexolone to decrease the levels, there was no significant effect seen for either of the drops. It must be considered that aminoglycosides are known to have toxic side effects and that they can influence the levels of SN which may be not diminished by low topical doses of corticosteroids or nonsteroidal antiinflammatory drugs. The high levels of the peptide are of relevance and may indicate a significant role of secretoneurin in the anterior segment of the eye. This should encourage performing functional studies.

Endogenous glucocorticoids inhibit scratching behavior induced by the administration of compound 48/80 in mice

In this study, we investigated the effects of endogenous glucocorticoids on the compound 48/80 (a condensation product of N-methyl-p-methoxyphenethylamine with formaldehyde)-induced mouse scratching behavior using either RU-486 (mifepristone), a glucocorticoid receptor antagonist, or a surgical resection of the adrenal glands. Subcutaneous injection of compound 48/80 induced not only a corticosterone elevation in the plasma but also an enhanced expression of corticotropin releasing hormone (CRH) mRNA in the paraventricular nucleus, which thus suggests that hypothalamic-pituitary-adrenal axis is activated by the compound 48/80-induced cutaneous reaction. Inhibition of such an endogenous glucocorticoid activity by RU-486 significantly increased the degree of scratching behavior at not only the early-phase (<60 min) but also the late-phase (>60 min) time course after the injection of compound 48/80. Since the elevation of the histamine levels in the plasma in the RU-486-treated mice was no longer found in late-phase scratching behavior, these results thus indicate that histamine is a dominant mediator responsible for early-phase scratching behavior, while different mediators other than histamine may be also involved in the induction of late-phase scratching behavior. Moreover, surgical removal of adrenal glands also significantly increased the compound 48/80-induced scratching behavior without affecting anxiety and locomotor parameters, indicating that endogenous glucocorticoids exert their anti-pururitogenic effects independently of changes in behavioral performance. In conclusion, endogenous glucocorticoid activity was found to suppress the compound 48/80-induced scratching behavior in mice.

Glucocorticoid inhibition of neuropathic limb edema and cutaneous neurogenic extravasation

Sciatic nerve section in rats evokes chronic limb edema, pain behavior, and hindpaw hyperalgesia, a syndrome resembling the complex regional pain syndrome type II (CRPS II or causalgia) in man. Glucocorticoids such as methylprednisolone (MP) have been used as analgesic and anti-edematous agents in patients suffering from CRPS, and interestingly these therapeutic effects appear to persist in some patients after stopping the medication. Similar to the CRPS clinical response to glucocorticoids, we now demonstrate that chronic hindpaw edema in the sciatic transection CRPS model is reversed by a continuous infusion of MP (3 mg/kg/day over 21 days), and this anti-edematous effect persists for at least 1 week after discontinuing MP. Furthermore, there is a chronic increase in spontaneous protein extravasation in the hindpaw skin of rats after sciatic transection, similar to the increased protein extravasation observed in the edematous hands of CRPS patients. A 2-week infusion of MP (3 mg/kg/day) reduced spontaneous protein extravasation in the hindpaw skin by 80%. We postulated that increased spontaneous neurogenic extravasation resulted in development of limb edema in both the animal model and the CRPS patient, and that the anti-edematous effects of MP are due to an inhibition of spontaneous extravasation. Additional experiments examined the inhibitory effects of MP infusion on electrically-evoked neurogenic extravasation in the hindpaw skin of normal rats. MP inhibition was dose- and time-dependent, with an ED(50) of 1.2 mg/kg/day for a 14-day continuous infusion of MP, and a maximum inhibitory effect requiring 17 days of MP infusion (3 mg/kg/day). MP (3 mg/kg/day for 14 days) also blocked both capsaicin- and SP-evoked neurogenic extravasation, indicating a post-junctional inhibitory effect. Our interpretation is that increased spontaneous neurogenic extravasation in this CRPS model contributed to the development and maintenance of hindpaw edema, and that chronic MP administration dose- and time-dependently blocked neurogenic extravasation at a post-junctional level, thus reversing spontaneous extravasation and limb edema in this model.

Glucocorticoid inhibition of neuropathic hyperalgesia and spinal Fos expression

Glucocorticoids are used to treat patients suffering from neuropathic pain and complex regional pain syndromes (CRPS). Previously we found that once-daily injections of the glucocorticoid methylprednisolone had no antihyperalgesic effect in the rat sciatic nerve transection model for CRPS, but on the basis of CRPS clinical data, we hypothesized that a continuous infusion of methylprednisolone might prove effective. We further postulated that the antihyperalgesic effects of glucocorticoids were mediated by the inhibition of spinal neuron hyperactivity and by the depletion of substance P or its NK(1) receptor. This study tested the effects of continuously infused methylprednisolone in sciatic nerve-transected rats. Continuous infusion of methylprednisolone (3 mg. kg(-1). d(-1) for 21 days), started after the development of neuropathic hyperalgesia, reversed both heat and mechanical hyperalgesia over 2 wk, and this effect persisted for at least 1 wk after discontinuing methylprednisolone. In addition, continuous methylprednisolone infusion partially reversed nerve injury-evoked Fos expression in the dorsal horns, suggesting that glucocorticoids can inhibit the spinal neuron hyperactivity induced by chronic sciatic nerve transection. Finally, no changes were observed in spinal substance P or NK(1) immunoreactivity after chronic methylprednisolone infusion, suggesting that the depletion of this neuropeptide or its receptor does not contribute to the antihyperalgesic actions of glucocorticoids.

Effects of relaxation and stress on the capsaicin-induced local inflammatory response

OBJECTIVE

Although stress is known to modulate the inflammatory response, there has been little experimental examination of the effects of stress and stress reduction on inflammation in humans. In particular, the effects of stress and relaxation on neurogenic inflammation have been minimally studied. This study examines the effects of three experimental manipulations: mental stress, relaxation, and control on the local inflammatory response evoked by the intradermal injection of capsaicin, the active ingredient in chili peppers.

METHODS

Fifty subjects (28 men and 22 women) were pretrained in relaxation using an imagery-based relaxation tape and then randomized to experimental condition. Subjects participated in an evening reactivity session including 20 minutes of a stress (Stroop test), relaxation (tape), or control (video) manipulation, followed by a capsaicin injection in the forearm. Digitized flare measurements were taken for 1 hour postcapsaicin, and measurements of cardiovascular variables, cortisol, adrenocorticotrophic hormone, and norepinephrine were taken at regular intervals.

RESULTS

The size of the maximum capsaicin-induced flare was significantly smaller in the relaxation condition than in the stress or control conditions, which did not differ from each other. Increases in norepinephrine, heart rate, and systolic blood pressure during the experimental task, but not after capsaicin, significantly predicted size of maximum flare and total area under the curve of flare measurements.

CONCLUSIONS

These findings suggest that stress reduction may affect local inflammatory processes. Results are consistent with sympathetic modulation of the effects of relaxation on the flare response.

Increased expression of annexin I and thioredoxin detected by two-dimensional gel electrophoresis of drug resistant human stomach cancer cells

The therapy of advanced cancer using chemotherapy alone or in combination with radiation or hyperthermia yields an overall response rate of about 20-50%. This success is often marred by the development of resistance to cytostatic drugs. Our aim was to study the global analysis of protein expression in the development of chemoresistance in vitro. We therefore used a cell culture model derived from the gastric carcinoma cell line EPG 85-257P. A classical multidrug-resistant subline EPG85-257RDB selected to daunorubicin and an atypical multidrug-resistant cell variant EPG85-257RNOV selected to mitoxantrone, were analysed using two-dimensional electrophoresis in immobilized pH-gradients (pH 4.0-8.0) in the first dimension and linear polyacrylamide gels (12%) in the second dimension. After staining with coomassie brilliant blue, image analysis was performed using the PDQuest system. Spots of interest were isolated using preparative two-dimensional electrophoresis and subjected to microsequencing. A total of 241 spots from the EPG85-257RDB-standard and 289 spots from the EPG85-257RNOV-standard could be matched to the EPG85-257P-standard. Microsequencing after enzymatic hydrolysis in gel, mass spectrometric data and sequencing of the peptides after their fractionation using microbore HPLC identified that two proteins annexin I and thioredoxin were overexpressed in chemoresistant cell lines. Annexin I was present in both the classical and the atypical multidrug-resistant cells. Thioredoxin was found to be overexpressed only in the atypical multidrug-resistant cell line.

Lipocortin 1 and chemokine modulation of granulocyte and monocyte accumulation in experimental inflammation

1. Migration of blood-derived leukocytes to tissue sites of inflammation is a hallmark of the response that the host organizes to counteract an insult or a trauma or an infection. A cascade of events is then activated to allow interaction between the leukocyte and the endothelium of postcapillary venule, and this cascade is finely regulated such that mechanisms of negative control are operating side by side with pathways that promote and sustain the extravasation process. Examples of both these positive and negative regulatory systems are discussed here. 2. In vivo accumulation of specific subtypes of leukocytes in response to application of selective chemokines operates through an indirect mechanism that includes the perivenular mast cell and, in particular, the mast cell-derived amines, such as histamine and serotonin. In fact, treatments of animals with (1) histamine H1 or serotonin antagonists or with (2) the mast cell stabilizer cromolyn or with (3) prior depletion of intact mast cells are maneuvers that successfully reduce eosinophil, neutrophil and monocyte extravasation in response to eotaxin, interleukin-8 or monocyte chemoattractant protein-1, respectively. A model in which histamine provides a P-selectin-dependent rolling phenomenon is then postulated. 3. The discovery that neutrophil-derived lipocortin 1 acts as an autocrine mediator with an inhibitory action on the emigration (diapedesis) process confirms the growing body of experimental data that showed that exogenously administered lipocortin 1 and lipocortin 1 mimetics (peptide Ac2-26) potently inhibit neutrophil extravasation in response to different stimuli. Externalization of lipocortin 1 on the plasma membrane of adherent neutrophils reduces their rate of passage through the endothelial gaps. Because cell-associated lipocortin 1 levels are under the partial control of corticosterone (endogenous circulating glucocorticoid hormone in rodents) and dexamethasone (a synthetic glucocorticoid hormone with a potent anti-inflammatory profile), a model is proposed in which a balance between anti-inflammatory (lipocortin 1, etc.) and pro-inflammatory (adhesion molecules, cytokines and chemokines) mediators explains the difference in the rate of leukocyte accumulation during the different stages of the host inflammatory response. 4. In conclusion, this review emphasizes the importance of in vivo experimental systems as a valid way of obtaining pertinent observations and reiterates the importance of negative regulatory mechanisms on the leukocyte extravasation process operating within the host.

Topical glucocorticoids and the skin--mechanisms of action: an update

The topical glucocorticoids (GCs) represent the treatment of choice for many types of inflammatory dermatoses. Despite the extensive use of this class of drugs as first line therapy the mechanism of their action is uncertain. It is clear that the multiplicity of actions of the topical GCs is an important facet of their scope in the treatment of dermal disorders. The aim of this update is to review past and current theories regarding how these agents might work. Current understanding of the molecular mechanisms of GC action has advanced significantly over the past decade with the realisation that multiple systems are responsible for transduction of GC effects at a molecular level. The two primary modes of action are via interaction directly with DNA or indirectly through modulation of specific transcription factors: the endpoint in both cases being modulation of specific protein synthesis. Both of these mechanisms will be discussed. In particular this review will concentrate on the possibility that a GC-inducible protein, termed lipocortin 1, may have a significant role to play in the anti-inflammatory actions of these drugs. Additionally it has become apparent that several inflammatory enzymes induced in inflammation are sites of inhibitory action of the GCs, and the possibility that this occurs in the skin will be discussed paying particular attention to the inducible phospholipase A2, nitric oxide synthase and cyclooxygenase systems.