Inflammatory and immune reactions associated with stratum corneum and neutrophils in sterile pustular dermatoses

Preclinical study of the topical anti-inflammatory activity of Cyperus rotundus L. extract (Cyperaceae) in models of skin inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Cyperus rotundus L. (Cyperaceae) is considered one of the most widely distributed plant species in the world, especially in tropical and subtropical regions. In addition, it is commonly used in India, China and Japan in traditional medicine to treat different diseases, including dermatitis and other skin disorders.

AIM OF THE STUDY

To investigate the topical anti-inflammatory activity of C. rotundus rhizome ethanolic extract in models of acute and chronic dermatitis.

MATERIALS AND METHODS

Phytochemical analysis was carried out using High-performance liquid chromatography-ultraviolet detection (HPLC/UV) to determine the presence of quercetin and chlorogenic acid in C. rotundus extract. Topical anti-inflammmatory effects of C. rotundus extract were evaluated on arachidonic acid (AA) and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation in mice. Skin biopsies were collected and submitted to histological and enzymatic analysis to evaluate the C. rotundus effect in leukocyte migration into inflamed tissue. Antiproliferative activity of C. rotundus was confirmed by PCNA immunostained cell analysis. Systemic and possible adverse effects of topical treatment with C. rotundus were evaluated by the skin atrophy and same organ weights. In addition, the glucocorticoid receptor (GR) antagonist mifepristone was used to investigate possible GR-mediated mechanisms of action.

RESULTS

The phytochemical analysis show that C. rotundus ethanol extract contains 45 μg/g of chlorogenic acid. Topical treatment with C. rotundus extract reduced ear edema and cellular infiltrate in acute and chronic skin inflammation models. Moreover, mice topically treated with C. rotundus exhibited decrease in TPA-induced keratinocyte hyperproliferation. Relevantly, topical treatment with C. rotundus did not caused skin atrophy or changes in lymphoid organ weight. The anti-inflammatory effect of C. rotundus was not influenced by the GR antagonist.

CONCLUSION

The results here demonstrate for the first time the topical anti-inflammatory and antiproliferative efficacy of C. rotundus extract, suggesting that the extract could be a potential new therapeutic tool for the treatment of inflammatory skin disorders.

Psoriasiform skin disease in transgenic pigs with high-copy ectopic expression of human integrins α2 and β1

Psoriasis is a complex human-specific disease characterized by perturbed keratinocyte proliferation and a pro-inflammatory environment in the skin. Porcine skin architecture and immunity are very similar to that in humans, rendering the pig a suitable animal model for studying the biology and treatment of psoriasis. Expression of integrins, which is normally confined to the basal layer of the epidermis, is maintained in suprabasal keratinocytes in psoriatic skin, modulating proliferation and differentiation as well as leukocyte infiltration. Here, we generated minipigs co-expressing integrins α2 and β1 in suprabasal epidermal layers. Integrin-transgenic minipigs born into the project displayed skin phenotypes that correlated with the number of inserted transgenes. Molecular analyses were in good concordance with histological observations of psoriatic hallmarks, including hypogranulosis and T-lymphocyte infiltration. These findings mark the first creation of minipigs with a psoriasiform phenotype resembling human psoriasis and demonstrate that integrin signaling plays a key role in psoriasis pathology.

Summary: A cloned porcine disease model to advance topical treatment in the debilitating skin disorder psoriasis.

Phase III clinical study of maxacalcitol ointment in patients with palmoplantar pustulosis: A randomized, double-blind, placebo-controlled trial

Palmoplantar pustulosis (PPP) often shows resistance to treatment. Vitamin D3 analog (VitD3 ) has been widely used for the treatment of psoriasis, however, the efficacy and safety of topical VitD3 treatment of PPP are not fully confirmed. Maxacalcitol topical ointment (22-oxacalcitriol [OCT]) was applied twice daily for 8 weeks. Evaluation of efficacy was based on scored skin findings for three main symptoms (erythema, pustules/vesicles and keratinization/scales). The primary and secondary end-points were the total and symptom-specific scores of skin findings, respectively. A total of 188 patients with moderate or severe PPP were enrolled in the study and were randomized into either the OCT group (n = 95) or placebo group (n = 93). The total scores (mean ± standard error) of skin findings at the last observation adjusting for those on day 1 were 5.0 ± 0.20 in the OCT group and 6.9 ± 0.20 in the placebo group. There was a significant decrease in the total score of skin findings in the OCT group compared with the placebo group (P < 0.0001). In particular, the score of pustules/vesicles drastically decreased in the OCT group. In terms of safety, the incidence of adverse reactions in the OCT and placebo groups were 11.6% and 9.7%, respectively. These results indicate that OCT is effective and highly safe in the management of PPP. Topical OCT treatment was found to show a potent action on pustules/vesicles thereby contributing to the cure of PPP.

Animal models for the molecular and mechanistic study of lymphatic biology and disease

The development of animal model systems for the study of the lymphatic system has resulted in an explosion of information regarding the mechanisms governing lymphatic development and the diseases associated with lymphatic dysfunction. Animal studies have led to a new molecular model of embryonic lymphatic vascular development, and have provided insight into the pathophysiology of both inherited and acquired lymphatic insufficiency. It has become apparent, however, that the importance of the lymphatic system to human disease extends, beyond its role in lymphedema, to many other diverse pathologic processes, including, very notably, inflammation and tumor lymphangiogenesis. Here, we have undertaken a systematic review of the models as they relate to molecular and functional characterization of the development, maturation, genetics, heritable and acquired diseases, and neoplastic implications of the lymphatic system. The translation of these advances into therapies for human diseases associated with lymphatic dysfunction will require the continued study of the lymphatic system through robust animal disease models that simulate their human counterparts.

Inflammatory manifestations of experimental lymphatic insufficiency

BACKGROUND

Sustained lymph stagnation engenders a pathological response that is complex and not well characterized. Tissue inflammation in lymphedema may reflect either an active or passive consequence of impaired immune traffic.

METHODS AND FINDINGS

We studied an experimental model of acute post-surgical lymphedema in the tails of female hairless, immunocompetent SKH-1 mice. We performed in vivo imaging of impaired immune traffic in experimental, murine acquired lymphatic insufficiency. We demonstrated impaired mobilization of immunocompetent cells from the lymphedematous region. These findings correlated with histopathological alterations and large-scale transcriptional profiling results. We found intense inflammatory changes in the dermis and the subdermis. The molecular pattern in the RNA extracted from the whole tissue was dominated by the upregulation of genes related to acute inflammation, immune response, complement activation, wound healing, fibrosis, and oxidative stress response.

CONCLUSIONS

We have characterized a mouse model of acute, acquired lymphedema using in vivo functional imaging and histopathological correlation. The model closely simulates the volume response, histopathology, and lymphoscintigraphic characteristics of human acquired lymphedema, and the response is accompanied by an increase in the number and size of microlymphatic structures in the lymphedematous cutaneous tissues. Molecular characterization through clustering of genes with known functions provides insights into processes and signaling pathways that compose the acute tissue response to lymph stagnation. Further study of genes identified through this effort will continue to elucidate the molecular mechanisms and lead to potential therapeutic strategies for lymphatic vascular insufficiency.