(+)-Episesamin inhibits adipogenesis and exerts anti-inflammatory effects in 3T3-L1 (pre)adipocytes by sustained Wnt signaling, down-regulation of PPARγ and induction of iNOS.

Obesity and its associated health risks still demand for effective therapeutic strategies. Drugs and compositions derived from Oriental medicine such as green tea polyphenols attract growing attention. Previously, an extract from the Japanese spice bush Lindera obtusiloba (L. obtusiloba) traditionally used for treatment of inflammation and prevention of liver damage was shown to inhibit adipogenesis. Aiming for the active principle of this extract (+)-episesamin was identified, isolated and applied in adipogenic research using 3T3-L1 (pre)adipocytes, an established cell line for studying adipogenesis. With an IC50 of 10µM (+)-episesamin effectively reduced the growth of 3T3-L1 preadipocytes and decreased hormone-induced 3T3-L1 differentiation as shown by reduced accumulation of intracellular lipid droplets and diminished protein expression of GLUT-4 and vascular endothelial growth factor. Mechanistically, the presence of (+)-episesamin during hormone-induced differentiation provoked a reduced phosphorylation of ERK1/2 and ß-catenin along with a reduced protein expression of peroxisome proliferator-activated receptor γ and a strongly increased protein expression of iNOS. Treatment of mature adipocytes with (+)-episesamin resulted in a reduction of intracellular stored lipid droplets and induced the proapoptotic enzymes caspases-3/-7. Besides interfering with adipogenesis, (+)-episesamin showed anti-inflammatory activity by counteracting the lipopolysaccharide- and tumor necrosis factor α-induced secretion of interleukin 6 by 3T3-L1 preadipocytes. In conclusion, (+)-episesamin seems to be the active drug in the L. obtusiloba extract being responsible for the inhibition of adipogenesis and, thus, should be evaluated as a novel potential complementary treatment for obesity.

Ulcerative colitis: immune function, tissue fibrosis and current therapeutic considerations.

BACKGROUND: Ulcerative colitis (UC) is a complex disease in which the interaction of genetic, environmental and microbial factors drives chronic intestinal inflammation that finally leads to extensive tissue fibrosis. DISCUSSION: The present review discusses the current knowledge on genetic susceptibility, especially of the IL-12/IL-23 pathway, the pathophysiologic role of the involved cytokines (e.g. IL-13, IL-23, TGFß1) and immune cells (e.g. T cells, epithelial cells, fibroblasts) in UC followed by an overview on actual therapeutic considerations. These future therapies will target selectively the involved cell types by blocking their activation and its downstream signalling, by inhibiting their migration to the inflamed site and by anti-cytokine strategies. This may avoid-when initiated in time-the perpetuation of the inflammatory mechanisms thus preventing fibrosis. With respect to animal models that have guided the most productive efforts for understanding human inflammatory bowel disease, these will be shortly discussed in the respective context.

A hepatoprotective Lindera obtusiloba extract suppresses growth and attenuates insulin like growth factor-1 receptor signaling and NF-kappaB activity in human liver cancer cell lines.

BACKGROUND: In traditional Chinese and Korean medicine, an aqueous extract derived from wood and bark of the Japanese spice bush Lindera obtusiloba (L.obtusiloba) is applied to treat inflammations and chronic liver diseases including hepatocellular carcinoma. We previously demonstrated anti-fibrotic effects of L.obtusiloba extract in hepatic stellate cells. Thus, we here consequently examine anti-neoplastic effects of L.obtusiloba extract on human hepatocellular carcinoma (HCC) cell lines and the signaling pathways involved. METHODS: Four human HCC cell lines representing diverse stages of differentiation were treated with L.obtusiloba extract, standardized according to its known suppressive effects on proliferation and TGF-ß-expression. Beside measurement of proliferation, invasion and apoptosis, effects on signal transduction and NF-κB-activity were determined. RESULTS: L.obtusiloba extract inhibited proliferation and induced apoptosis in all HCC cell lines and provoked a reduced basal and IGF-1-induced activation of the IGF-1R signaling cascade and a reduced transcriptional NF-κB-activity, particularly in the poorly differentiated SK-Hep1 cells. Pointing to anti-angiogenic effects, L.obtusiloba extract attenuated the basal and IGF-1-induced expression of hypoxia inducible factor-1α, vascular endothelial growth factor, peroxisome proliferator-activated receptor-γ, cyclooxygenase-2 and inducible nitric oxide synthase. CONCLUSIONS: The traditional application of the extract is confirmed by our experimental data. Due to its potential to inhibit critical receptor tyrosine kinases involved in HCC progression via the IGF-1 signaling pathway and NF-κB, the standardized L.obtusiloba extract should be further analysed for its active compounds and explored as (complementary) treatment option for HCC.

Randomized, placebo-controlled, double-blind trial of Boswellia serrata in maintaining remission of Crohn's disease: good safety profile but lack of efficacy.

BACKGROUND: Complementary therapies are frequently used by patients with inflammatory bowel disease (IBD). The aim of this study was to evaluate the efficacy and safety of long-term therapy with a new Boswellia serrata extract (Boswelan, PS0201Bo) in maintaining remission in patients with Crohn's disease (CD). METHODS: In 22 German centers a double-blind, placebo-controlled, randomized, parallel study was performed. In all, 108 outpatients with CD in clinical remission were included. Patients were randomized to Boswelan (3×2 capsules/day; 400 mg each) or placebo for 52 weeks. The primary endpoint was the proportion of patients in whom remission was maintained throughout the 52 weeks. Secondary endpoints were time to relapse, changes of Crohn's Disease Activity Index (CDAI), and IBD Questionnaire (IBDQ) scores. RESULTS: The trial was prematurely terminated due to insufficient discrimination of drug and placebo with regard to the primary efficacy endpoint. A total of 82 patients were randomized to Boswelan (n=42) or placebo (n=40). Sixty-six patients could be analyzed for efficacy. 59.9% of the actively treated patients and 55.3% of the placebo group stayed in remission (P=0.85). The mean time to diagnosis of relapse was 171 days for the active group and 185 days for the placebo group (P=0.69). With respect to CDAI, IBDQ, and laboratory measurements of inflammation, no advantages in favor of active treatment were detected. Regarding safety concerns, no disadvantages of taking the drug compared to placebo were observed. CONCLUSIONS: The trial confirmed good tolerability of a new Boswellia serrata extract, Boswelan, in long-term treatment of CD. However, superiority versus placebo in maintenance therapy of remission could not be demonstrated.

An active extract of Lindera obtusiloba inhibits adipogenesis via sustained Wnt signaling and exerts anti-inflammatory effects in the 3T3-L1 preadipocytes.

Obesity, the related metabolic syndrome and associated liver diseases represent an epidemic problem and demand for effective therapeutic strategies. In this regard, natural compounds derived from Oriental medicine such as green tea polyphenols influencing adipogenesis attract growing attention. In Korea, an aqueous extract from the Japanese spice bush Lindera obtusiloba is traditionally used for treatment of inflammation and prevention of liver damage. We here investigated effects of the L. obtusiloba extract on cell growth, apoptosis, Wnt signaling and differentiation of (im)mature adipocytes using 3T3-L1, an established cell line for studying adipogenesis. L. obtusiloba extract reduced the de novo DNA synthesis of 3T3-L1 preadipocytes in a concentration dependent manner with an IC(50) of ∼135 µg/ml paralleled by induction of caspase 3/7 mediated apoptosis. Hormone-induced 3T3 L1 differentiation in the presence of L. obtusiloba extract resulted in a reduced accumulation of intracellular lipid droplets by 70%, in down-regulated expression of the adipogenesis-associated proteins glucose transporter-4 and vascular endothelial growth factor, in reduced secretion of the proadipogenic matrix metalloproteinase-2, and in dampened phosphorylation of the Wnt pathway effector protein ß-catenin with subsequent diminished expression of the peroxisome proliferator-activated receptor-γ. Treatment of mature adipocytes with L. obtusiloba extract also significantly reduced intracellular lipid droplets. In addition to this strong interference of L. obtusiloba extract with adipogenesis, L. obtusiloba extract exerted anti-inflammatory effects. L. obtusiloba extract significantly attenuated lipopolysaccharide- and tumor necrosis factor α-induced secretion of IL-6 by preadipocytes, thus influencing insulin resistance and inflammatory state characterizing obesity. In conclusion, extracts of L. obtusiloba should be evaluated as a potential complementary treatment option for obesity associated with the metabolic syndrome.

Extracts of Lindera obtusiloba induce antifibrotic effects in hepatic stellate cells via suppression of a TGF-beta-mediated profibrotic gene expression pattern.

Liver fibrosis is characterized by high expression of the key profibrogenic cytokine transforming growth factor (TGF)-beta and the natural tissue inhibitor of metalloproteinases (TIMP)-1, leading to substantial accumulation of extracellular matrix. Liver fibrosis originates from various chronic liver diseases, such as chronic viral hepatitis that, to date, cannot be treated sufficiently. Thus, novel therapeutics, for example, those derived from Oriental medicine, have gained growing attention. In Korea, extracts prepared from Lindera obtusiloba are used for centuries for treatment of inflammation, improvement of blood circulation and prevention of liver damage, but experimental evidence of their efficacy is lacking. We studied direct antifibrotic effects in activated hepatic stellate cells (HSCs), the main target cell in the fibrotic liver. L. obtusiloba extract (135 mug/ml) reduced the de novo DNA synthesis of activated rat and human HSCs by about 90%, which was not accompanied by cytotoxicity of HSC, primary hepatocytes and HepG2 cells, pointing to induction of cellular quiescence. As determined by quantitative polymerase chain reaction, simultaneous treatment of HSCs with TGF-beta and L. obtusiloba extract resulted in reduction of TIMP-1 expression to baseline level, disruption of the autocrine loop of TGF-beta autoinduction and increased expression of fibrolytic matrix metalloproteinase (MMP)-3. In addition, L. obtusiloba reduced gelatinolytic activity of HSC by interfering with profibrogenic MMP-2 activity. Since L. obtusiloba extract prevented intracellular oxidative stress experimentally induced by tert-butylhydroperoxide, we concluded that the direct antifibrotic effect of L. obtusiloba extract might be mediated by antioxidant activity. Thus, L. obtusiloba, traditionally used in Oriental medicine, may complement treatment of chronic liver disease.

Prevention of colitis-associated carcinogenesis in a mouse model by diet supplementation with ursodeoxycholic acid.

Bile acids in the intestinal lumen contribute to the homeostatic regulation of proliferation and death of the colonic epithelial cells: Deoxycholic acid (DCA) appears to enhance and ursodeoxycholic acid (UDCA) to attenuate the process of chemically induced carcinogenesis. We studied the effects of UDCA on colitis-related colorectal carcinogenesis. Three groups of 25 mice were given 0.7% dextran sulphate in drinking water for 7 days and pure water for 10 days and were fed a standard diet containing double iron concentration. In 2 groups, the diet was supplemented with 0.2% cholic acid (CA), the precursor of DCA, or with 0.4% UDCA. After 15 cycles, the histology, the expression of MUC2, beta-catenin, p27 and p16 and the fecal water concentration of DCA and UDCA were investigated. All animals showed colitis with similar severity and histologic as well as immunophenotypic alterations, resembling those of human colitis. Among the animals fed the nonsupplemented diet, 46% developed colorectal adenocarcinomas and 54% anal-rectal squamous cell carcinomas. The prevalence of dysplasia and carcinomas did not change significantly in the animals given CA. Among the mice fed with UDCA, none developed adenocarcinomas and 20% squamous carcinomas. Dysplastic lesions were found in 88%, 67% and 40% of each group, respectively. The prevalence of dysplasia as well as of carcinoma showed an inverse relationship to the UDCA concentration in the fecal water. These data indicate that UDCA suppresses colitis-associated carcinogenesis. This model is suitable for investigation of the mechanism of the anticarcinogenic effect of UDCA in vivo.

The elongated first fibronectin type III domain of collagen XIV is an inducer of quiescence and differentiation in fibroblasts and preadipocytes.

Collagen XIV (CXIV) is a fibril-associated collagen that is mainly expressed in well differentiated tissues and in late embryonic development. Because CXIV is almost absent in proliferating and/or dedifferentiated tissues, a functional role in maintaining cell differentiation is suspected. We demonstrate antiproliferative, quiescence- and differentiation-inducing effects of human CXIV and its recombinant fragments on mesenchymal cells. In primary human fibroblasts, in mouse 3T3 fibroblasts and in 3T3-L1 preadipocytes, CXIV reduced de novo DNA synthesis by 75%, whereas cell numbers and viability remained unaltered. Cells showed no signs of apoptosis, and maximal proliferation was restored when serum was supplemented, thus indicating that CXIV induced reversible cellular quiescence. Exposure of fibroblasts to CXIV in vitro led to cellular bundles and clusters. CXIV also triggered trans-differentiation of 3T3-L1 preadipocytes into adipocytes, as could be shown by lipid accumulation and by expression of the glucose transporter Glut4. These effects were also observed with the amino-terminal recombinant fragment Gln(29)-Pro(154) that harbors the first fibronectin type III domain and a 39-amino-acid extension, whereas no activity was found for all other recombinant CXIV fragments. Based on these finding the development of small molecular analogs that modulate fibroblast cell growth and differentiation, e.g. in wound healing and fibrosis, seems feasible.

Standards of medical treatment and nutrition in Crohn's disease.

Crohn's disease is a condition of chronic inflammation potentially involving any location of the alimentary tract from mouth to anus but with a propensity for the distal small bowel and proximal large bowel. Frequent complications include stricture and fistula. Numerous extra-intestinal manifestations may also be present. The aetiology of Crohn's disease is incompletely understood, and therapy, although generally effective in alleviating the symptoms, is not curative. Due to the heterogeneity of the disease a major need for the therapeutic approach is the ability to define subgroups with distinct characteristics. However, with regard to the heterogeneity of demographic, anatomic and disease behaviour characteristics, distillation of the numerous possible phenotypes in simple categories is a formidable task. In the present review the focus will be on clinically relevant situations providing therapeutic algorithms according to international guidelines.