Inflammation & Allergy-Drug Targets (Discontinued) - Volume 10, Issue 6, 2011

Traditional knowledge of clinical, laboratorial, and endoscopic orders regarding ulcerative colitis and Crohn's disease has begun to be implemented by the revolutionary data from genetic studies. Eversince many decades ago it has been clear that Inflammatory bowel diseases are complex multifactorial disorders wherein gut-confined and/or environmental factors must synergize with genetic components to effect the full-blown disorder. The sequencing of the human genome and the generation of public resources of single nucleotide polymorphisms permitted the conduction of powerful population based genome-wide association studies. The latter have increased the number of the identified susceptibility loci to 99. In this review we touched on two pathways that make true susceptibility genes for Inflammatory bowel diseases; gene loci that confer specific risk for ulcerative colitis and Crohn's disease were discussed in detail.

Morinda citrifolia L. (Rubiaceae), commonly called noni, is a traditional folk medicinal plant with a long history of use for several diseases. Its anti-inflammation activity has been proposed, but detailed knowledge of this antiinflammation mechanism remains unclear. Here, we investigated the effects of noni extract and its major bioactive component damnacanthal on anti-inflammation in vivo as well as in vitro. Our data demonstrate that noni extract and its bioactive component damnacanthal exhibit suppression of inflammation as evidenced by the suppression of paw and ear edema in rats and mice, and down-regulation of lipopolysaccharide-induced nuclear factor-κB (NF-κB) activity, respectively. As a result, the expression of pro-cytokines, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) were suppressed in the presence of damnacanthal. These results provide a potential use of damnacanthal in the treatment of inflammatory-related diseases.

Sphingolipids are mediators of inflammation; changes in their cellular concentration modulate specific cellular functions. Investigations of sphingosine kinases (SphK) and sphingosine 1 phosphate (S1P) in TNFα driven murine models of rheumatoid arthritis (RA), identified SphK/S1P as important intermediaries in TNFα mediated synovial proinflammatory pathways. Fibroblast-like synoviocytes (FLS) are key contributors to RA pathogenesis and express both SphK 1 and 2. To pinpoint the mechanisms of SphK effects in the inflammatory response of murine FLS in vitro, we derived SphK1 null (SphK1-/-) FLS and SphK1 wild-type (SphK1+/+) FLS from the knee joints of B6 mice. Significantly less MMP1a and IL-6 were produced by mTNFα-stimulated SphK1-/- FLS versus SphK1+/+ FLS. Trends toward less PGE2 as well as activated, ERK 1/2 and STAT3 were present in SphK1-/- FLS versus SphK1+/+ FLS. Thus genetic inhibition of SphK1 activity resulted in decreased expression of inflammatory mediators and decreased activation of inflammatory pathways in TNFα stimulated murine FLS. This decreased inflammatory phenotype in FLS lacking SphK1 activity is consistent with the attenuated TNF-α-driven arthritis in vivo in SphK1 deficient mice and adds to the understanding of the mechanistic role of SpK1/S1P in rheumatoid arthritis. Thus, specific therapeutic can be targeted with SphK inhibitors in rheumatoid arthritis.

Allergic rhinitis (AR) is the most common allergic disease. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines classify AR according to its duration and severity and suggest recommended treatments, but there is evidence that these guidelines are insufficiently followed. Considering the validity of histopathological data, physicians are more likely to be persuaded by such information on AR. Thus, we attempted to define the severity of AR by nasal cytology on the basis of the ARIA classification. We examined 64 patients with AR caused by sensitization to grass pollen. We clinically defined AR according to the ARIA classification and performed nasal cytology by Rhino-probe sampling, staining and reading by optical microscopic observation. Clinically, 22 (34.4%), 21 (32.8%), 10 (15.6%), and 11 (17.2%) patients had mild intermittent, moderate-to-severe intermittent, mild persistent, and moderate-to-severe persistent AR, respectively. Nasal cytology detected neutrophils in 49 patients, eosinophils in 41 patients, mast cells in 21 patients, and lymphocytes or plasma cells in 28 patients. The patients with moderate-to-severe AR had significantly more mast cells and lymphocytes/ plasma cells than those with mild AR. Our findings demonstrate that the ARIA classification of AR severity is associated with different cell counts in nasal cytology; especially, moderate-to-severe AR shows significantly increased counts of mast cells and lymphocyte or plasma cells. The ease of performing nasal cytology ensures is feasibility as an office AR diagnostic procedure for primary care physicians, able to indicate when anti-inflammatory treatments, such as intranasal corticosteroids and subcutaneous or sublingual allergen immunotherapy, are needed.

The barrier abnormality, a loss-of-function mutation in the gene encoding filaggrin (FLG), which is linked to the incidence of atopic dermatitis (AD), is a recently discovered but important factor in the pathogenesis of AD. To investigate this issue in greater detail, mice that have a genetic defect (FLG) in barrier function will provide a model of AD closer to the human disease. Flaky tail (Flgft) mice, essentially deficient in filaggrin, recently have been introduced to investigate the role of filaggrin on AD. These mice showed eczematous skin lesion in the steady state in line with increased of total IgE and Th17 expression in the skin. There is also an altered skin barrier function as a key element of AD either outside-to-inside barrier function or vice versa in Flgft mice. Moreover, like human AD, these mice showed enhanced percutaneous allergen priming or response to cutaneous stimulants. Application of mite allergen in Flgft mice, even without prior barrier disruption, remarkably enhanced both the clinical manifestations and the laboratory findings that correspond to indicators of human AD. These features of Flgft mice allow us to investigate further the role of filaggrin in AD, and the knowledge obtained using these mice will be quite useful to develop a new therapeutic target for AD.

Atopic dermatitis (AD) is a pruritic chronic inflammatory disease of the skin that is triggered by an underlying complicated interplay between the genetics of the individual and stimulation by allergens. Patients with AD demonstrate compromised barrier function that leads to activation of keratinocytes and immune cells which favor a strong Th2 bias. As a result of this immunological bias such patients also suffer from secondary pathogenic infections. A wide array of cytokines and chemokines interact to yield symptoms characteristic of AD. In addition, the involvement of different immunological cell types compounds our difficulty in understanding its immunopathogenesis. The use of various mouse models and transgenics has allowed us to intricately examine the functioning of the various molecules identified to play a role in AD. Such mouse models have also aided in the testing and development of various therapeutics for AD. This review is focused on examining the various factors contributing to the pathogenesis and exacerbation of AD as well as current treatments for AD. There is scope for improving the therapy of AD patients and thereby allowing them a better quality of life.

The inflammatory cytokine, vascular endothelial growth factor (VEGF), plays a central role in human growth and development, and vascular maintenance. VEGF mediated angiogenesis is essential for tumor growth, as well as exudative age-related macular degeneration, proliferative diabetic retinopathy and retinopathy of prematurity, all of which are characterized by abnormal neovascularization. Ischemia and inflammation also lead to VEGF-mediated breakdown of the blood-retinal barrier, which causes vision diminishing macular edema. To combat these effects, anti-VEGF drugs (antibodies, aptamers, and tyrosine kinase inhibitors) have been developed for both systemic and local (intraocular) use. The next drug to receive regulatory approval will probably be aflibercept (VEGF-Trap), a fusion protein with high VEGF affinity attributed to binding sequences from the native receptors VEGFR1 and VEGFR2. Aflibercept monotherapy significantly reduces tumor growth and extends survival in several orthotropic animal models, and has both prevented and reduced the growth of experimental choroidal neovascularization. Ongoing phase III trials are evaluating the effectiveness of aflibercept combined with chemotherapy in patients with advanced carcinomas. The phase III VELOUR trial determined that patients receiving aflibercept with irinotecan/5-FU as second line chemotherapy for metastatic colorectal cancer experienced extended progression free survival and overall survival. Intravitreal aflibercept improved visual acuity in patients with exudative age-related macular degeneration and was non-inferior to standard therapy (ranibizumab). Ongoing phase III trials are investigating the use of aflibercept for retinal vein occlusions and diabetic macular edema. A regulatory approval application for use in exudative macular degeneration has been filed, with a decision expected by late 2011.

Despite increasing knowledge about molecular pathways in pathogenesis of chronic liver disease, selective therapeutic options are scarce, especially in advanced diseases characterized by scarring of the liver (termed fibrosis) or even complete cirrhosis. Sustained hepatic inflammation as a result to various types of injury (e.g., hepatitis C, nonalcoholic steatohepatitis) is generally accepted to represent the key prerequisite for fibrogenesis. Liver inflammation is characterized by an activation of distinct chemokine pathways in the liver and the circulation allowing distinct immune cell populations to enter the liver via sinusoids and postsinusoidal venules. Recent investigations have shed light on the intimate interactions between the fibrogenic hepatic stellate cell (HSC) and infiltrating immune cells, which fundamentally drive liver scarring. Experimental fibrosis and inflammation models have demonstrated that disruption of chemokine pathways such as CCL2 (MCP-1) or its receptor CCR2, CCL5 (RANTES) or CCR1 / CCR5 and others may efficiently prevent collagen deposition, by targeting monocytes and macrophages, T-cell populations or NKT cells. However, immigration of certain mononuclear cells may even be beneficial in the course of fibrosis. Infiltrating NK cells and monocyte-derived macrophage subsets can promote resolution of extracellular matrix. This emphasizes that hepatic fibrosis is not a unidirectional process, but can be reverted up to a certain point. The present review aims at summarizing the contribution of immune cell infiltration as well as related chemokine systems to experimental liver fibrosis and will discuss possible therapeutic applications in humans, with a special emphasis on the monocyte/macrophage lineage and their related chemokine pathways.