Pharmacological inhibition of porcupine induces regression of experimental skin fibrosis by targeting Wnt signalling.

OBJECTIVES: Wnt signalling has been implicated in activating a fibrogenic programme in fibroblasts in systemic sclerosis (SSc). Porcupine is an O-acyltransferase required for secretion of Wnt proteins in mammals. Here, we aimed to evaluate the antifibrotic effects of pharmacological inhibition of porcupine in preclinical models of SSc. METHODS: The porcupine inhibitor GNF6231 was evaluated in the mouse models of bleomycin-induced skin fibrosis, in tight-skin-1 mice, in murine sclerodermatous chronic-graft-versus-host disease (cGvHD) and in fibrosis induced by a constitutively active transforming growth factor-ß-receptor I. RESULTS: Treatment with pharmacologically relevant and well-tolerated doses of GNF6231 inhibited the activation of Wnt signalling in fibrotic murine skin. GNF6231 ameliorated skin fibrosis in all four models. Treatment with GNF6231 also reduced pulmonary fibrosis associated with murine cGvHD. Most importantly, GNF6231 prevented progression of fibrosis and showed evidence of reversal of established fibrosis. CONCLUSIONS: These data suggest that targeting the Wnt pathway through inhibition of porcupine provides a potential therapeutic approach to fibrosis in SSc. This is of particular interest, as a close analogue of GNF6231 has already demonstrated robust pathway inhibition in humans and could be available for clinical trials.

Blockade of p38 Mitogen-Activated Protein Kinase Inhibits Murine Sclerodermatous Chronic Graft-versus-Host Disease.

Bone marrow transplantation (BMT) of B10.D2 mice into sublethally irradiated BALB/c mice across minor histocompatibility loci is a well-established animal model for human sclerodermatous chronic graft-versus-host disease (Scl-cGVHD) and systemic sclerosis (SSc). The p38 mitogen-activated protein kinase (MAPK) pathway is a key regulator of inflammation and cytokine production. Furthermore, the activation of p38 MAPK plays an important role in collagen production in SSc. We investigated the effects of p38 MAPK inhibitor, VX-702, on Scl-cGVHD mice. VX-702 was orally administered to Scl-cGVHD mice from day 7 to 35 after BMT. We compared skin fibrosis of Scl-cGVHD mice between the VX-702-treated group and control group. Allogeneic BMT increased the phosphorylation of p38 MAPK in the skin. The administration of VX-702 attenuated the skin fibrosis of Scl-cGVHD compared to the control mice. Immunohistochemical staining showed that VX-702 suppressed the infiltration of CD4+ T cells, CD8+ T cells, and CD11b+ cells into the dermis of Scl-cGVHD mice compared to the control mice. VX-702 attenuated the mRNA expression of extracellular matrix and fibrogenic cytokines, such as IL-6 and IL-13, in the skin of Scl-cGVHD mice. In addition, VX-702 directly inhibited collagen production from fibroblasts in vitro. VX-702 was shown to be a promising candidate for use in treating patients with Scl-cGVHD and SSc.

Inhibition of EGFR Tyrosine Kinase by Erlotinib Prevents Sclerodermatous Graft-Versus-Host Disease in a Mouse Model.

Chronic graft-versus-host disease (GVHD) follows allogeneic hematopoietic stem cell transplantation. It results from alloreactive processes induced by minor histocompatibility antigen incompatibilities leading to the activation of CD4 T cells and the development of fibrosis and inflammation of the skin and visceral organs and autoimmunity that resemble systemic sclerosis. EGFR is a ubiquitous cell receptor deeply involved in cell proliferation, differentiation, and motility. EGFR has recently been implicated in autoimmune and fibrotic diseases. Therefore, we tested whether Erlotinib, an EGFR tyrosine kinase inhibitor, can prevent sclerodermatous GVHD (Scl-GVHD). Scl-GVHD was induced in BALB/c mice by B10.D2 bone marrow and spleen cell transplantation. Transplanted mice displayed severe clinical symptoms including alopecia, fibrosis of the skin and visceral organs, vasculitis, and diarrhea. The symptoms were reversed in mice treated with Erlotinib. These beneficial effects were mediated by the decreased production of activated/memory CD4(+) T cells and the reduction in T-cell infiltration of the skin and visceral organs along with a decrease in IFN-γ and IL-13 production and autoimmune B-cell activation. The improvement provided by Erlotinib in the mouse model of Scl-GVHD supplies a rationale for the evaluation of Erlotinib in the management of patients affected by chronic GVHD.

Mycophenolate mofetil and daclizumab targeting T lymphocytes in bleomycin-induced experimental scleroderma.

BACKGROUND: T lymphocytes induce the transformation of fibroblasts into myofibroblasts, the main mediators of fibrogenesis. The inosine 5'-monophosphate dehydrogenase inhibitor mycophenolate mofetil (MMF) and the anti-CD25 monoclonal antibody daclizumab (DCZ) have been reported to suppress the proliferation of T lymphocytes. AIM: To evaluate the preventive effects of MMF and DCZ in early stages of bleomycin (BLM)-induced scleroderma. METHODS: This study involved five groups of Balb/c mice (n = 10 per group). Mice in four of the groups were injected subcutaneously (SC) with BLM [100 µg/day in 100 µL phosphate-buffered saline (PBS)] for 4 weeks; the remaining (control) group received only 100 µL PBS. Three of the BLM-treated groups also received either intraperitoneal MMF 50 or 150 mg/kg/day, or SC DCZ 100 µg/week. At the end of the fourth week, all mice were killed, and blood and tissue samples were obtained for further analysis. RESULTS: In the BLM-treated group, increases were seen in inflammatory-cell infiltration, α-smooth muscle actin-positive (α-SMA+) fibroblastic cell count, tissue hydroxyproline content, and dermal thickness. Dermal fibrosis was histopathologically prominent. In BLM-treated mice also given MMF or DCZ, inflammatory-cell infiltration, tissue hydroxyproline content and dermal thickness were decreased. In the MMF groups, decreases were also noted in α-SMA+ fibroblastic cell count. CONCLUSION: In this BLM-induced dermal fibrosis model, MMF and DCZ treatments prevented the development of dermal fibrosis. Further studies are needed to evaluate whether targeting T lymphocytes is effective in resolving pre-existing fibrosis in human scleroderma.

Proteasome inhibition prevents development of experimental dermal fibrosis.

Scleroderma is a chronic fibrotic disorder. Bortezomib, a proteasome inhibitor, is reported to attenuate experimentally induced renal and cardiac fibrosis. This study aimed to evaluate the preventive and therapeutic efficacies of bortezomib on a bleomycin (BLM)-induced scleroderma model. Dermal fibrosis was induced in Balb/c mice by subcutaneous BLM (100 µg/day) injections. Bortezomib (1.6 mg/kg twice/week) was applied intraperitoneally to BLM-injected mice during the first 3 weeks for preventive interventions and in the second 3 weeks for therapeutic interventions. IL-4 and TGF-ß1 serum levels, dermal thicknesses, dermal inflammatory cell counts, and α-SMA-positive fibroblastic cell counts were determined, and type-I collagen, NF-κBp65, I-κBα, and JNK1 expressions were assessed. BLM applications increased serum IL-4 level, dermal inflammatory cell counts, α-SMA-positive cell counts, expression of type-I collagen, NF-κB, and JNK1, and dermal thickness in early stage of fibrosis, but serum IL-4 level and dermal inflammatory cell counts showed no increases in later stages. As a preventive intervention, bortezomib decreased dermal thickness, inflammatory cell infiltrations, fibroblastic activity, and expression of type-I collagen, NF-κB, and JNK1, but did not decrease fibroblastic activity and dermal thickness at later stages of fibrosis. Inflammatory status is prominent in the early stage of dermal fibrosis, but declines at later stages. In BLM-induced dermal fibrosis, bortezomib has a preventive anti-fibrotic and anti-inflammatory efficacy, but has no therapeutic anti-fibrotic efficacy in preexisting tissue fibrosis. These findings suggest that the effect of proteasome inhibition in early stages of dermal fibrosis may be related to its anti-inflammatory effects.

Blockade of interleukin-6 receptor alleviates disease in mouse model of scleroderma.

Activation of fibroblasts by interleukin-6 (IL-6) is implicated in the pathogenesis of scleroderma, suggesting that the inhibition of fibroblast activation may be a promising scleroderma treatment. In this study, we used an IL-6 blocking antibody (Ab) and Il-6 knockout (Il-6KO) mice to examine the role of IL-6 in the bleomycin (BLM)-induced mouse model of scleroderma. BLM was administered to C57BL/6 and Il-6KO mice to induce dermal sclerosis. BLM-treated and control phosphate-buffered saline-treated mice were treated with anti-mouse IL-6 receptor monoclonal Ab (MR16-1). Disease severity was evaluated by measuring dermal thickness and skin hardness, by counting the numbers of α-smooth muscle actin-positive cells and mast cells, and by examining the cutaneous draining lymph nodes. C57BL/6 mice with BLM induced scleroderma had elevated serum IL-6 levels and more severe dermal sclerosis than Il-6KO mice. Weekly administration of MR16-1, but not control Ab, prevented and improved dermal sclerosis, and also attenuated swelling of the draining lymph nodes. MR16-1 suppressed α-smooth muscle actin induction in IL-6-stimulated Il-6KO fibroblasts. Our results indicate that IL-6 contributes to BLM induced dermal sclerosis and that IL-6 receptor-specific monoclonal Ab may improve the symptoms of scleroderma by suppressing fibroblast activation.

[Graft-versus-host disease (GvHD) - an update. Part 2: prognosis and therapy of GvHD]. / Graft-versus-Host-Disease (GvHD) - ein Update. Teil 2: Prognose und Therapie der GvHD.

Graft-versus-host disease (GvHD) remains one of the major complications after allogeneic stem cell transplantation (SCT) and is responsible for morbidity, mortality and decrease in quality of life of patients after SCT. The most important preventive approach is the selection of a donor with best possible HLA compatibility between donor and recipient. Basic prophylaxis of acute GvHD begins already prior to transplantation and usually consists of cyclosporine with or without methotrexate. In the past few years, many new therapies have been introduced for the treatment of acute and chronic GvHD. Extracorporeal photopheresis (ECP), for example, represents a promising treatment option for acute and chronic GvHD with very few side effects. For chronic GvHD mTOR inhibitors (sirolimus, everolimus) may replace calcineurin-inhibitors with the advantage of not inducing malignant skin tumors. Guidelines are available ort he management of acute and chronic GvHD. While pathophysiology, classification and skin manifestations of GvHD have been already presented in the first part of this article, this second part covers the prognosis, prevention and treatment of GvHD.

CpG oligodeoxynucleotides prevent the development of scleroderma-like syndrome in tight-skin mice by stimulating a Th1 immune response.

Tight-skin (Tsk/+) mice develop a disease similar to human scleroderma, characterized by the spontaneous appearance of cutaneous hyperplasia, anti-nuclear antibodies, and emphysema. T helper (Th) 2 cells secreting interleukin (IL)-4 are known to play a critical role in the etiopathogenesis of this disease. Th2-mediated responses can be blocked by treatment with synthetic oligodeoxynucleotides (ODN) containing immunomodulatory CpG motifs. Thus, we examined whether CpG ODN might be of therapeutic benefit in Tsk/+ mice. Administering CpG ODN to Tsk/+ mice every 3 wk starting at 1 wk of age abrogated skin fibrosis. This reduction in skin thickness persisted even after the cessation of therapy, and was accompanied by increased serum levels of IL-12 and an increased ratio of T cells available to secrete interferon-gamma rather than IL-4. CpG ODN therapy also reduced autoantibody production, but did not inhibit the incidence of lung emphysema. Delaying the initiation of CpG ODN treatment until 6 wk of age failed to prevent skin disease. These results indicate that by preferentially promoting the development of a Th1-biased immune milieu in young Tsk/+ mice, CpG ODN can ameliorate Th2-driven scleroderma-like syndrome.

Esclerodermia localizada/morfea / Localized scleroderma/morphea

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Effect of superoxide dismutase on bleomycin-induced dermal sclerosis: implications for the treatment of systemic sclerosis.

Bleomycin has a chemical toxicity capable of inducing superoxide radicals, which are suggested to play an important part in bleomycin-induced pulmonary fibrosis. We have recently established a mouse model for scleroderma induced by repeated local injections of bleomycin. In this study, we examined the inhibitory effect of superoxide dismutase on the development of dermal sclerosis induced by bleomycin using this mouse model. PC-superoxide dismutase, which is a lecithinized superoxide dismutase with high tissue accumulation and long half-life in blood, was administered (3000 U per kg; dissolved in 5% mannitol) 3 h before the injection of bleomycin in C3H mice for 3 wk. Systemic PC-superoxide dismutase markedly inhibited the development of dermal sclerosis, which was also accompanied by a decrease in the number of infiltrating mast cells and eosinophils. Furthermore, the hydroxyproline content in the skin was significantly reduced, as compared with mice treated with bleomycin only or bleomycin and 5% mannitol. In a separate experiment, after the development of dermal sclerosis following treatment with bleomycin for 3 wk, PC-superoxide dismutase was administered for 2 wk. Histologic examination again revealed a reduction of dermal sclerosis, followed by a significant associate in the number of both mast cells and eosinophils. The hydroxyproline content in the skin was not significantly decreased, however, even after injections of high amounts of PC-superoxide dismutase (30,000 U per kg). These results support the involvement of oxygen free radicals in bleomycin-induced dermal sclerosis, and also indicate that administration of superoxide dismutase may be effective in the therapeutic approach in systemic sclerosis.

[Compression therapy in post-thrombotic syndrome]. / Kompressionstherapie beim postthrombotischen Syndrom.

The most important aim of compression therapy in postthrombotic legs is prevention of dermatosclerosis and ulcus cruris. For the acute stage of leg swelling and for venous ulceration we prefer compression bandages ("therapy phase"). The effect of compression therapy with bandages depend on the material of the used bandages (short or long-stretch bandages), the stretching the bandages are applied with, the number of layers, the local pads and on well done application of the bandages. After removal of oedema compression therapy should be continued with medical compression stockings ("maintenance phase"). Compression stockings should be fit on carefully and be checked from time to time to guarantee their application by the patient.