Anti-hyaluronidase Activity in Vitro and Amelioration of Mouse Experimental Dermatitis by Tomato Saponin, Esculeoside A.

The increasing incidence of atopic dermatitis during recent decades has prompted the development of safe and effective agents for prevention of atopic diseases. Esculeoside A, a glycoside of spirosolane type, is identified as a major component in ripe tomato fruits. The present study investigated the effects of esculeoside A and its aglycon esculeogenin A on hyaluronidase activity in vitro and antiallergy in experimental dermatitis mice. Esculeogenin A/esculeoside A (esculeogenin A equivalent) with an IC50 of about 2 µM/9 µM dose-dependently inhibited hyaluronidase activity measured by a modified Morgan-Elson method. Oral treatment with esculeoside A 10 mg/kg of experimental dermatitis mice for 4 weeks significantly decreased the skin clinical score to 2.5 without any detectable side effects compared with 6.75 of the control. The scratching frequency of esculeoside A 100 mg/kg application was decreased significantly as 107.5 times compared with 296.67 times of the control. Thus, the present study showed that esculeoside A/esculeogenin A significantly blocks hyaluronidase activity in vitro and that esculeoside A ameliorates mouse experimental dermatitis.

[Effects of zhuhong ointment on MMPs activities and production by HSF].

HuaFu Shengji is the primary traditional Chinese medicine (TCM) therapy for treating chronic skin ulcer. The high activities of the protein enzyme in the wound fluids is one of the main cause of healing delay. In order to investigate the effect of TCM Zhuhong ointment for promoting wound healing. This research focused on its influence on matrix metalloproteinase (MMP) activities in wound fluids with TCM Yang syndromes, directly on the activated MMP-1,2 activities in vitro and on MMP-1,-2,-9 production by HSF. 8 wound fluid samples were collected, which were diagnosed Yang Syndromes in TCM. Wound fluid activities of MMP-2 and MMP-9 were measured by gelatin zymogram assay. MMP-1 and MMP-2 activities in vitro were measured by substrate cleavage. CCK-8 was used to observe the toxicity of Zhuhong ointment on HSF. MMP-1,-2,-9 production by HSF were detected by confocal microscope. Zhuhong ointment from 1 to 25 g x L(-1) obviously inhibited MMP-2 activity in wound fluid. When Zhuhong ointment was over 5 g x L(-1), it showed significantly inhibitory effect on wound fluid MMP-9 activity. In vitro study, when the mercury concentration was 320 mg x L(-1), Zhuhong ointment solution directly inhibited both MMP-1 activity and MMP-2. But mercury concentration from 0.51-2.56 mg x L(-1), it could activate MMP-1 activity, and from 0.51-64 mg x L(-1), activate MMP-2 activity instead. The mercury concentration when Zhuhong ointment saturated in DMEM was 39.6 mg x L(-1). When the mercury concentration was over 1.23 mg x L(-1), Zhuhong ointment showed toxicity to HSF. At 1.23, 0.62, 0.31 mg x L(-1) of mercury concentration, it increased MMP-1 expression by HSF, and at 1.23, 0.62 mg x L(-1), decreased MMP-2 expression. However, at 1.23, 0.62, 0.31 mg x L(-1), it decreased MMP-9 expression. At higher concentration, Zhuhong ointment can inhibit MMP-2, MMP-9 activities in wound fluid with dose-dependent way and show a direct inhibitory effect on activated MMP-1 and MMP-2 in vitro. But at a lower concentration, it showed two-way adjustment, with increased MMP-1, MMP-2 activities and its expression by HSF and decreased MMP-9 activity.

Ulcerative dermatitis in C57BL/6 mice lacking stearoyl CoA desaturase 1.

Ulcerative dermatitis (UD) is a common cause of morbidity and euthanasia in mice with a C57BL/6 (B6) background. The purposes of the current study were to determine whether UD lesions could be reliably produced in B6 mice lacking stearoyl-CoA desaturase 1 (SCD1(-/-) mice), to ascertain whether the UD lesions in SCD1(-/-) mice were similar to those found in other B6 mice, and to characterize the cell invasion phenotype of Staphlococcus xylosus cultured from the lesions. S. xylosus isolates from the environment and human skin were used as controls. SCD1(-/-) (n = 8 per group) and nontransgenic B6 control mice (n = 22 mice pooled from 3 groups that received different concentrations of conjugated linoleic acid) were fed standard rodent chow or a semipurified diet (NIH AIN76A) for 4 wk. Samples from other B6 mice with UD (field cases; n = 7) also were submitted for histology and culture. All of the SCD1(-/-) mice developed UD lesions by 4 wk on NIH AIN76A. None of SCD1(-/-) fed standard rodent chow and none of the wildtype B6 mice fed NIH AIN76A developed UD. Supplementation with conjugated linoleic acid did not affect ulcerogenesis. UD lesions in SCD1(-/-) mice and field cases were grossly and histologically similar. S. xylosus was isolated from SCD1(-/-) mice with UD (71%) and field cases of UD (43%). These isolates were the most cell-invasive, followed by the environmental isolate, and finally the human skin isolate. Our results provide a basis for further pathologic and clinical study of UD.

Inhibition of 5-lipoxygenase and skin inflammation by the aerial parts of Artemisia capillaris and its constituents.

The aerial parts of Artemisia capillaris Thunberg (Compositae) have been used in Chinese medicine as a liver protective agent, diuretic, and for amelioration of skin inflammatory conditions. This study was conducted to establish the scientific rationale for treating skin inflammation and to find active principles from A. capillaris. To accomplish these goals, the 70% ethanol extract of the aerial parts of A. capillaris (AR) was prepared and its 5-lipoxygenase (5-LOX) inhibitory action was studied since 5-LOX products are known to be involved in several allergic and skin inflammatory disorders. AR showed potent inhibitory activity against 5-LOX-catalyzed leukotriene production by ionophore-induced rat basophilic leukemia-1 cells, with an IC(50) of < 1.0 µg/mL. Nine major compounds, scopoletin, scopolin, scoparone, esculetin, quercetin, capillarisin, isorhamnetin, 3-O-robinobioside, isorhamnetin 3-O-galactoside and chlorogenic acid, were isolated from A. capillaris, and their effects were examined to identify the active principle(s). Several coumarin and flavonoid derivatives were found to be 5-LOX inhibitors. In particular, esculetin and quercetin were potent inhibitors, with IC(50) values of 6.6 and 0.7 µM, respectively. Against arachidonic acid-induced ear edema in mice, AR, and esculetin strongly inhibited edematic response. AR and esculetin also inhibited delayed-type hypersensitivity response in mice. In conclusion, AR and some of their major constituents are 5-LOX inhibitors, and these in vitro and in vivo activities may contribute to the therapeutic potential of AR in skin inflammatory disorders in traditional medicine.

Inhibition of the IL-2-inducible tyrosine kinase (Itk) activity: a new concept for the therapy of inflammatory skin diseases.

T-cell-mediated processes play an essential role in the pathogenesis of several inflammatory skin diseases such as atopic dermatitis, allergic contact dermatitis and psoriasis. The aim of this study was to investigate the role of the IL-2-inducible tyrosine kinase (Itk), an enzyme acting downstream of the T-cell receptor (TCR), in T-cell-dependent skin inflammation using three approaches. Itk knockout mice display significantly reduced inflammatory symptoms in mouse models of acute and subacute contact hypersensitivity (CHS) reactions. Systemic administration of a novel small molecule Itk inhibitor, Compound 44, created by chemical optimization of an initial high-throughput screening hit, inhibited Itk's activity with an IC50 in the nanomolar range. Compound 44 substantially reduced proinflammatory immune responses in vitro and in vivo after systemic administration in two acute CHS models. In addition, our data reveal that human Itk, comparable to its murine homologue, is expressed mainly in T cells and is increased in lesional skin from patients with atopic dermatitis and allergic contact dermatitis. Finally, silencing of Itk by RNA interference in primary human T cells efficiently blocks TCR-induced lymphokine secretion. In conclusion, Itk represents an interesting new target for the therapy of T-cell-mediated inflammatory skin diseases.

The promise of plant polyphenols as the golden standard skin anti-inflammatory agents.

Inflammation is a key event in the skin normally occurring in response to the constant exposure to environmental and endogenous stimuli as well as to accidental damage. It also plays a central role in the pathogenesis of major cutaneous pathologies, ultimately resulting in skin carcinogenesis. As the acute mild inflammatory process is mainly adaptive in nature, chronic inflammation is a multi-factorial and complex noxious process, extremely difficult to combat. The wealth of data documenting the involvement of redox-dependent regulatory and damaging processes in the skin inflammation has prompted research on a steadily growing number of plant-derived active substances, mainly polyphenols, and selected principally on the basis of their free radical scavenging and antioxidant properties. In spite of the wide recognition of their anti-inflammatory efficacy in vitro, the clinical use for the prevention and treatment of major skin inflammatory conditions is in most cases yet to be conclusively proven. The complex nature of the cutaneous inflammatory process involves oxygen (ROS), nitrogen (RNS) and lipid reactive species, but is also driven by other mechanisms highlighted in these recent years, related to the regulation of gene expression, and to metabolic and signaling pathways that are ROS/RNS-independent. The screening of the enormous array of plant secondary metabolites, first of all polyphenols, for new effective and safe anti-inflammatory agents should be rather directed towards molecules targeting specific inflammatory pathways recognized to be active in the peculiar skin compartment.

Evaluation of ATPase-positive Langerhans' cells in skin lesions of lupus erythematosus and experimentally induced inflammations.

We examined the time-dependent dynamics of epidermal Langerhans' cells (LC) in human systemic lupus erythematosus (SLE), in MRL/Mp-lpr/lpr(MRL/lpr) mice, and in various experimental cutaneous inflammations, such as the Arthus reaction, dinitrochlorobenzene allergic dermatitis, and croton oil primary irritant dermatitis, in order to clarify the pathomechanisms of lupus skin lesions. The numbers of LC in untreated SLE patients with newly developed skin lesions decreased in the central lesional sites and increased significantly in the peripheral lesional sites. In MRL/lpr mice, the number of LC increased significantly in the central lesional sites during the initial stage and increased in the peripheral lesional sites and decreased in the central lesional sites 2-4 weeks after the onset of skin lesions. In contrast, with experimental cutaneous inflammations of guinea pigs, the increase in numbers of LC in the peripheral lesional sites was not significant during the time course of the reaction. These results suggest that the increased numbers of LC during the active and early stages of skin lesions in human SLE and MRL/lpr mice are closely related to the specific spontaneous development of skin lesions, unlike the dynamics of LC in experimental cutaneous inflammations.