Immunohistochemical studies on NAP-1/IL-8 in contact eczema and atopic dermatitis

Beneficial effects of ROCEN (Topical Nano-arthrocen) on atopic dermatitis in mice

Objective

Atopic dermatitis (AD) is a chronic inflammatory skin disease mainly caused by immune stimuli. The current study was conducted to investigate the effects of ROCEN and to compare it with betamethasone (Beta) on mice subjected to AD.

Methods

First, the safety of topical ROCEN was tested to determine possible sensitization induction in vivo. Then, the mice were subjected to oxazolone (Oxa) to induce chronic AD. Consequently, they underwent treatment with ROCEN and Beta. Scratching and wiping behaviors related to dermatitis were evaluated in treated animals for 35 days. The histopathology and immunohistochemistry (IHC) analysis of interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) cytokines were performed on the dorsal skin of the treated mice.

Results

Topical administration of ROCEN and Beta to the dorsum of sensitized mice for 5 weeks significantly alleviated scratching and wiping symptoms and reduced erythema, scaling, and edema in the skin of the mice with AD. Moreover, histological indices showed that ROCEN effectively reduced leucocyte infiltration and improved skin healing parameters in treated AD mice. Application of ROCEN or Beta reduced IHC markers including IL-8 and TNF-α significantly.

Conclusion

ROCEN alleviated the AD symptoms similar to betamethasone in an experimental animal model.

Interleukin-8 Levels in the Stratum Corneum as a Biomarker for Monitoring Therapeutic Effect in Atopic Dermatitis Patients

INTRODUCTION

The stratum corneum contains several growth factors and cytokines that are synthesized in keratinocytes. We previously reported that the amount of interleukin-8 in the stratum corneum (scIL-8) is related to the severity of local skin inflammation in atopic dermatitis (AD). However, it is unknown whether scIL-8 levels reflect pharmacologic responses to a therapeutic intervention in AD patients. Therefore, in this study, we aimed to investigate whether the improvement of dermatitis in AD is correlated with scIL-8 levels before and after topical corticosteroid treatment.

METHODS

Stratum corneum samples were collected from 22 AD patients using the noninvasive tape-stripping method before treatment, 2 weeks after topical treatment, and 4-6 weeks after treatment.

RESULTS

scIL-8 levels on the forearm reduced significantly from 790 ± 348 pg/mg before treatment to 163 ± 68 pg/mg 2 weeks after treatment and 100 ± 37 pg/mg 4-6 weeks after corticosteroid treatment. scIL-8 levels on the abdomen also reduced significantly from 902 ± 391 to 142 ± 38 pg/mg at the end of study. The reduction in scIL-8 levels was associated with the improvement in local skin severity in AD. We also found that scIL-8 levels, along with blood biomarker levels (serum thymus and activation-regulated chemokine, lactate dehydrogenase, and %eosinophil), decreased significantly after the treatment.

CONCLUSION

The scIL-8 concentration decreases with improvements in skin symptoms in AD patients after topical corticosteroid treatment; thus, it may be a suitable biomarker for monitoring therapeutic effects in AD patients.

Interleukin-8 content in the stratum corneum as an indicator of the severity of inflammation in the lesions of atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is an inflammatory skin disease characterized by both acute and chronic eczema. Various markers are used to clinically evaluate the severity of AD. In order to identify a marker of local severity of AD, we measured IL-8, IL-18, vascular endothelial growth factor (VEGF), and transforming growth factor-α (TGF-α) levels in the stratum corneum (scIL-8, scIL-18, scVEGF and scTGF-α) and evaluated the correlation between the levels of these cytokines and the clinical severity scores of localized skin lesions.

METHODS

Stratum corneum samples were collected from the skin lesions of 50 patients with AD using the tape-stripping technique, and the scIL-8, scIL-18, scVEGF and scTGF-α levels were evaluated using the ELISA method. The trans-epidermal water loss and skin water content of the lesions were also measured prior to tape stripping.

RESULTS

The levels of scIL-8, scIL-18, scVEGF and scTGF-α were significantly higher in patients with AD than in healthy controls. Additionally, the levels of scIL-8, scIL-18 and scVEGF significantly correlated with the severity of AD.

CONCLUSIONS

Among these cytokines, scIL-8 showed the highest correlation with the severity scores of lesions in AD as well as other parameters. Our results also suggest that measuring cytokines in the stratum corneum by using ELISA combined with tape stripping is a convenient method to evaluate the severity of skin lesions in AD.

Localization of IL-8 and Complement Components in Lesional Skin of Psoriasis vulgaris and Pustulosis palmaris et plantaris

BACKGROUND

Munro's microabscesses are a characteristic histopathologic feature of psoriasis vulgaris; however, the pathomechanisms underlying the migration of transepidermal leukocytes (PMNs) have not been fully elucidated yet.

OBJECTIVE AND METHODS

Since the lesional scale extracts contain potent chemoattractants, such as IL-8 and C5a fragments, we studied their location in the lesions of psoriasis vulgaris and PPP with immunohistochemical techniques.

RESULTS

Localization of IL-8 was not detected in the subcorneal keratinocytes but was demonstrated only in the basal keratinocytes together with migrating PMNs. In contrast, the presence of a complement fragment, C3b, was observed on the cell membranes of subcorneal keratinocytes, suggesting that these were the sites of complement activation.

CONCLUSION

Such distinct localization of IL-8 and complement components suggests that the intraepidermal migration of PMNs takes place first according to the concentration gradient of IL-8, and thereafter they are guided by complement components to the final destination, the subcorneal portion of the lesional skin.

Staphylococcus aureus peptidoglycan stimulates granulocyte macrophage colony-stimulating factor production from human epidermal keratinocytes via mitogen-activated protein kinases

Epidermal keratinocytes with atopic dermatitis (AD) overproduce mediators such as granulocyte macrophage colony-stimulating factor (GM-CSF), which are associated with pathology of AD. We found that peptidoglycan (PGN) of Staphylococcus aureus, which is frequently observed in lesion with AD, induced the production of numerous mediators such as GM-CSF and regulated on activation, normal T-cell expressed and secreted. Moreover, PGN phosphorylated extracellular-signal-regulated kinases and p38 mitogen-activated protein kinase, which were involved in the induction of GM-CSF expression. These results suggested that PGN of S. aureus directly exacerbates inflammation of inflammatory skin disease.

Interleukin-1-stimulated secretion of interleukin-8 and growth-related oncogene-alpha demonstrates greatly enhanced keratinocyte growth in human raft cultured epidermis

The CXC chemokines, interleukin-8 and growth-related oncogenealpha, are known to play a prominent part in wound healing as well as inflammatory skin disorders, including psoriasis. Both chemokines are potent neutrophil activators and were discussed as potential stimuli in keratinocyte growth. We examined the action of growth-related oncogene alpha and interleukin-8 in organotypic raft culture, which resembles in vivo skin in several respects. Addition of growth-related oncogene alpha and interleukin-8 resulted in a time- and concentration-dependent epidermal hyperproliferation in organotypic cultures. In cryostat sections an increased number of epidermal layers as well as significantly elevated number of Ki-67-stained keratinocytes indicate marked hyperproliferation with no evidence for the reduction of apoptotic cells. Terminal differentiation was shown to proceed in a regular fashion with formation of a cornified layer and the expression of suprabasal keratins in addition to the presence of differentiation markers. Interleukin-8-mediated hyperproliferation was inhibited by a blocking human monoclonal antibody. To demonstrate a specific receptor-mediated action of growth-related oncogene and interleukin-8, we used a CXC receptor 2 monoclonal antibody or a CXC receptor 2 selective nonpeptide antagonist, both of which lead to inhibition of interleukin-8-mediated hyperproliferation. Interleukin-1alpha caused induction of interleukin-8 and growth-related oncogene alpha mRNA as well as marked epidermal hyperproliferation. The interleukin-1alpha-mediated hyperproliferation was markedly reduced by both the interleukin-8-specific antibody and the CXC receptor 2 antagonist, indicating close correlation between the interleukin-8/CXC receptor 2 pathway and interleukin-1-induced keratinocyte growth stimulation. Our data indicate that interleukin-1 induces overexpression of interleukin-8 and growth-related oncogene alpha in human keratinocytes. These changes correlate with characteristic functional alterations of the epidermis as observed in psoriasis and wound healing.

Pathophysiology of pruritus in atopic dermatitis: an overview

Pruritus is an essential feature of atopic dermatitis (AD) and the diagnosis of active AD cannot be made without the history of itching. Because of the high impact on life quality, most of the patients measure the severity of eczema by the intensity of pruritus rather than appearance of skin lesions. However, although pruritus is a cardinal symptom of AD, its mechanism and association with the cutaneous nervous system is not completely understood. Recently, a considerable progress has been achieved in clarifying the complex pathophysiology of pruritus in AD. As a cutaneous sensory perception, itch requires excitation of neuropeptide-containing free nerve endings of unmyelinated nociceptor fibers. It is well known that histamine and acetylcholine provoke itch by direct binding to 'itch receptors' and several mediators such as neuropeptides, proteases or cytokines indirectly via histamine release. Interestingly, some variations of these complex mechanisms could be demonstrated in patients with AD. This review highlights the recent knowledge of different mechanisms which may be involved in regulating pruritus in patients with AD potentially leading to new therapeutic applications for the treatment of itch in AD.

Local cellular inflammation as a result of elective standardized vascular surgery

During surgery, incision of the skin under aseptic conditions is performed. Despite the absence of noxious agents, an inflammatory response may be induced. We studied the local inflammatory response in human skin as a result of surgical intervention, under aseptic conditions. Elective standardized vascular surgery served as a model. A series of skin biopsies was taken from the wound edge at different time points after first incision. Biopsies, directly taken at first incision were considered to represent normal skin. Additional biopsies were taken at 30 min after the start of surgery and just before closure of the wound, maximally 270 min after surgery. Kinetics of recruitment of cells, expression of adhesion molecules and the presence of pro-inflammatory cytokines was studied. Granulocytes were observed at first at 30 min after incision of the skin and their number increased in time. This granulocyte infiltration is paralleled by E-selectin expression on endothelial cells, which also was observed at first at 30 min after surgery with a further increase in number in time. Incision of the skin did not change P-selectin, ICAM-1, VCAM-1, TNFalpha, IL1alpha, IL1beta, IL6 and IL8 expression. These results show that incision of the skin under aseptic conditions during elective standardized vascular surgery induces local nonspecific cellular inflammation.

High levels of interleukin-8, soluble CD4 and soluble CD8 in bullous pemphigoid blister fluid. The relationship between local cytokine production and lesional T-cell activities

BACKGROUND

Bullous pemphigoid (BP) is an inflammatory subepidermal blistering disease associated with autoantibodies that recognize hemidesmosomal proteins. In addition to autoantibodies, the cell-mediated immune reaction is considered to play an important part in blister formation. Objectives To investigate some T-cell activation markers and inflammatory cytokines in the blister fluid and sera of patients with BP.

METHODS

We measured soluble CD4 (sCD4) and soluble CD8 (sCD8), which have been, respectively, associated with CD4 and CD8 T-cell activation. Enzyme-linked immunosorbent assays were also used to quantify the production of the leucocyte chemoattractant interleukin (IL) -8 and of the cytokines IL-1alpha, IL-1beta, IL-6, IL-10 and tumour necrosis factor-alpha in the blister fluid and sera of 11 patients with BP.

RESULTS

The mean +/- SD level of sCD4 in patients' blisters (42.4 +/- 25.0 units mL-1) was significantly elevated (P < 0.005) compared with that in their sera (11.2 +/- 8.9) and that in the suction blisters of 10 healthy people (11.4 +/- 5.4; P < 0.005). Mean +/- SD IL-8 concentrations in BP blisters (4683.6 +/- 3878.1 pg mL-1) were much higher than those in their sera (17.1 +/- 18.9; P < 0.001), and were very significantly elevated (P < 0.005) in comparison with those in suction blisters of healthy persons (512 +/- 292). sCD4 levels in BP blisters were inversely related to IL-10 levels (P = 0. 03, r2 = 0.85), IL-8 levels were positively related to sCD8 levels (P = 0.01, r2 = 0.54), and IL-1beta levels were positively related to sCD8 concentrations (P < 0.005, r2 = 0.65).

CONCLUSIONS

The correlations suggest that there is a delicately orchestrated network of cytokines and cell-mediated immunity operating in BP blisters.

Sulfur mustard upregulates the expression of interleukin-8 in cultured human keratinocytes

Although the morphological description of sulfur mustard (SM) injury is well characterised, little is known of the molecular mediators involved in cutaneous toxicity. Since infiltration by lymphocytes and PMNs represents one of the very first events observed in vivo upon exposure to SM, this study examined whether SM exposure can modify the expression by cultured human keratinocytes of interleukin-8, one of the most important chemoattractants for polymorphonuclear leukocytes (PMNs) in humans. Conditioned medium harvested from control keratinocyte cultures showed a gradual accumulation of this cytokine over time followed by a levelling off after 12 hours. Upon treatment with 10(-6) and 10(-5) M SM, no significant difference compared to the control situation was observed. After 6 h, a significantly higher amount of IL-8 was secreted by human keratinocytes treated with 10(-4) M SM and the accumulation of the cytokine persisted up to 24 h after exposure. The expression of IL-8 mRNA was assessed semi-quantitatively (RT-PCR) at the same time points in control and SM-treated (10(-4) M) human keratinocytes. When compared to control cultures, a clear upregulation of IL-8 mRNA levels was observed 6 and 12 h after SM exposure, which is consistent with the secretion pattern of the protein. The present observation indicates that increased secretion of IL-8 by human keratinocytes represents an early event of the inflammatory reaction following SM which is coherent with the reported delay in the recruitment of lymphocytes and PMNs observed in vivo.

Increased expression of keratinocyte interleukin-8 in human contact eczematous reactions to heavy metals

Heavy metal-induced contact eczematous human skin reactions to cobalt chloride and mercuric chloride were investigated for immunoreactivity to interleukin-8 (IL-8), by using an indirect immunoperoxidase staining technique. There was suprabasal epidermal staining for IL-8, with a decrease in the vicinity of areas with parakeratotic epithelium. However, in the immediate vicinity of a vesicular formation, intense staining of some apically situated keratinocytes was found. In addition, increased immunoreactivity over the acrosyringial area compared with the surrounding epidermis was obtained. These findings indicate an increased synthesis of keratinocyte IL-8 in contact eczematous skin.

Regulation of interleukin-8 receptor expression in human polymorphonuclear neutrophils

Interleukin-8, a neutrophil chemotactic agent, is known to have an active role in the induction of inflammatory response in a number of diseases. Although the activity of IL-8 is known to be through a receptor (IL-8R) on the surface of neutrophils, no information is available regarding the regulation of the IL-8R expression. The present study demonstrates that serum activated LPS at a concentration of 10 ng/ml induces expression of functionally active IL-8R by 120% within 30 min through de novo protein synthesis. The upregulated receptors could be detected by anti-IL-8R antibody and could also be demonstrated by autoradiography with crosslinking 125I IL-8. The serum-activated LPS-stimulated neutrophils migrated faster and showed higher Ca2+ flux over the unstimulated cells. The LPS-induced receptors were downregulated rapidly, about 85% of the receptor activity being lost within 90 min of incubation at 37 degrees C. The downregulation could be partially prevented by treatment with a cocktail of protease inhibitors, suggesting the possible involvement of protease(s) in this process. Both EDTA (100 microM) and bestatin (40 microM) afforded almost complete protection of the receptor from proteolytic cleavage indicating that the enzyme involved is a metalloprotease, possibly an aminopeptidase. The study shows that stimulation of PMNs with LPS leads to induction of IL-8R expression enhancing the IL-8-mediated biological responses and also provides evidence for post-stimulatory restoration of receptor level on the neutrophil surface by proteolytic cleavage of the amino-terminal end of the receptor.

Cytokine release by peripheral blood mononuclear cells is affected by 8-methoxypsoralen plus UV-A

Psoralen plus UV-A (PUVA) is an effective therapy for psoriasis but also for other inflammatory dermatoses. The precise mechanisms of action, however, are not absolutely clear. Therefore, the effect of PUVA on the release of the proinflammatory cytokines interleukin (IL)-1, IL-6, IL-8 and tumor necrosis factor alpha (TNF alpha) was studied. Peripheral blood mononuclear cells (PBMC) obtained from humans were incubated with 8-methoxypsoralen (8-MOP) and exposed to UV-A (20 kJ/m2). This treatment resulted in a significant reduction of IL-6 and IL-8 amounts in the supernatants. In addition, an inhibition of IL-1 beta and TNF alpha production by lipopolysaccharide (LPS)-stimulated PBMC was observed upon PUVA treatment. Accordingly, northern blot analysis showed decreased levels of mRNA encoding for IL-1 beta, IL-6, IL-8 and TNF alpha in PUVA-treated PBMC. Finally PBMC were obtained from psoriatics undergoing oral photochemotherapy before the beginning and after completion of treatment. The PBMC collected after PUVA spontaneously produced significantly less IL-6 and IL-8 in comparison to the respective samples obtained before therapy. A similar suppression of IL-1 beta and TNF alpha by in vivo PUVA was found in LPS-stimulated PBMC. The present data demonstrate that PUVA both in vitro and in vivo suppresses the production of the proinflammatory cytokines IL-1 beta, IL-6, IL-8 and TNF alpha by PBMC. Because these cytokines are important in the mediation of inflammatory reactions, one may speculate that the inhibitory effects could contribute to the antiinflammatory activity of PUVA.