Progress in suplatast tosilate research

Novel treatments of asthma and allergic diseases

The prevalence of allergic diseases has considerably increased, mostly in industrialized countries (> 20%), and asthma affects approximately 300 million individuals worldwide. Current therapies are able to control symptoms although they do not modulate immunological dysregulation that characterizes allergic diseases. Over the last 30 years, only a few new drugs have been introduced on the market and they all act on Th2-type response which has a critical role in the pathogenesis of allergic diseases. Recently, a new scenario has been opened on Th17-cells, Th1-type cytokines and innate immune system components involved in the inflammatory pathogenesis of asthma and other allergic diseases. These findings suggest a promising therapeutic role of new agents that block the action of specific cytokines. Furthermore, the concept of an intrinsic structural defect in the bronchial epithelium paves the way to innovative therapeutic strategies. In this review we present an update on therapies for allergic diseases with special focus on asthma.

Treatment of eosinophilic esophagitis: how should we manage the disease?

Eosinophilic esophagitis (EE) is a chronic clinicopathologic syndrome and is the latest inflammatory disease of the esophagus described in literature. It seems to have a multifactorial etiology. Its causes include exposure to food or airborne allergens that affect individuals who may be genetically predisposed and exposure to the acid could also modulate the inflammatory response at esophageal level. However, we currently do not know how each of these possible etiologic factors contribute to the development of the disease that is essential to define specific treatment. We have used 3 different therapeutic approaches that were effective in patients with EE: various antiinflammatory drugs that are useful in treating asthma, controlling the exposure to allergens, particularly with respect to dietary changes and dilation of the esophagus. Although none of these treatments have absolute advantages, they can efficiently control the symptoms and inflammation in a large number of patients. Each treatment option should be assessed on a case-by-case basis in accordance with the experience of each center, the patients' characteristics, their sensitivity to allergens and their preferences. This article provides the latest information on the different treatment options for patients with EE, analyzing the advantages and disadvantages of each pathology and it offers practical recommendations on how to manage these patients who are being more frequently diagnosed.

Immunopathogenesis of bronchial asthma

Bronchial asthma is a common immune-mediated disorder characterized by reversible airway inflammation, mucus production, and variable airflow obstruction with airway hyperresponsiveness. Allergen exposure results in the activation of numerous cells of the immune system, of which dendritic cells (DCs) and Th2 lymphocytes are of paramount importance. Although the epithelium was initially considered to function solely as a physical barrier, it is now evident that it plays a central role in the Th2-cell sensitization process due to its ability to activate DCs. Cytokines are inevitable factors in driving immune responses. To the list of numerous cytokines already known to be involved in the regulation of allergic reactions, new cytokines were added, such as TSLP, IL-25, and IL-33. IgE is also a central player in the allergic response. The activity of IgE is associated with a network of proteins, especially with its high- and low-affinity Fc receptors. Understanding the cellular and molecular mechanisms of allergic reactions helps us not only to understand the mechanisms of current treatments, but is also important for the identification of new targets for biological intervention. An IgE-specific monoclonal antibody, omalizumab, has already reached the clinic and similar biological agents will surely follow.

Early intervention with suplatast tosilate for prophylaxis of pediatric atopic asthma: a pilot study

The onset of asthma may be related to Th2 cytokine dominance at the time when food allergies occur several months after birth. This study investigated the effectiveness of early intervention with a Th2 cytokine inhibitor (suplatast tosilate) for prevention of asthma in infants with food allergies and atopic dermatitis. Suplatast tosilate dry syrup (6 mg/kg daily) or a histamine H(1)-blocker (ketotifen fumarate dry syrup: 0.06 mg/kg daily) was administered randomly to 53 infants with atopic dermatitis caused by food allergies. The primary endpoints were the incidence of asthma and the time to the onset of wheezing. The peripheral blood Th1/Th2 ratio, total IgE level, and eosinophil count were measured before and after treatment. After 24 months of treatment, the prevalence of asthma was significantly lower in the suplatast group (20.8%) than in the ketotifen group (65.6%, p < 0.01). Additionally, the time from the start of treatment to the initial episode of wheezing for infants who developed asthma was significantly longer in the suplatast group than the ketotifen group (p < 0.01). Furthermore, the eosinophil count was significantly decreased by suplatast treatment (p < 0.05), and there was a significant difference between the suplatast and ketotifen groups with respect to both the eosinophil count (p < 0.01) and the Th1/Th2 ratio (p < 0.05). The results of the present pilot study suggest that suplatast tosilate is useful for the primary prevention of wheezing and asthma in children.

Activity of sulfonium bisphosphonates on tumor cell lines

We investigated three series of sulfonium bisphosphonates for their activity in inhibiting the growth of three human tumor cell lines. The first series consisted of 6 cyclic sulfonium bisphosphonates, the most active species having an (average) IC50 of 89 microM. The second consisted of 10 phenylalkyl and phenylalkoxy bisphosphonates, the most active species having an IC50 of 18 microM. The third series consisted of 17 n-alkyl sulfonium bisphosphonates, the most active species having an IC50 of approximately 240 nM. Three QSAR models showed that the experimental cell growth inhibition results could be well predicted. We also determined the structures of one sulfonium bisphosphonate bound to farnesyl diphosphate synthase, finding that it binds exclusively to the dimethylallyl diphosphate binding site. These results are of interest since they show that sulfonium bisphosphonates can have potent activity against a variety of tumor cell lines, the most active species having IC50 values much lower than conventional nitrogen-containing bisphosphonates.