Thalidomide for Crohn's disease

A structure- and chemical genomics-based approach for repositioning of drugs against VCP/p97 ATPase

Valosin-containing protein (VCP/p97) ATPase (a.k.a. Cdc48) is a key member of the ER-associated protein degradation (ERAD) pathway. ERAD and VCP/p97 have been implicated in a multitude of human diseases, such as neurodegenerative diseases and cancer. Inhibition of VCP/p97 induces proteotoxic ER stress and cell death in cancer cells, making it an attractive target for cancer treatment. However, no drugs exist against this protein in the market. Repositioning of drugs towards new indications is an attractive alternative to the de novo drug development due to the potential for significantly shorter time to clinical translation. Here, we employed an integrative strategy for the repositioning of drugs as novel inhibitors of the VCP/p97 ATPase. We integrated structure-based virtual screening with the chemical genomics analysis of drug molecular signatures, and identified several candidate inhibitors of VCP/p97 ATPase. Importantly, experimental validation with cell-based and in vitro ATPase assays confirmed three (ebastine, astemizole and clotrimazole) out of seven tested candidates (~40% true hit rate) as direct inhibitors of VCP/p97 and ERAD. This study introduces an effective integrative strategy for drug repositioning, and identified new drugs against the VCP/p97/ERAD pathway in human diseases.

Safety and efficacy of immunomodulators and biologics during pregnancy and lactation for the treatment of inflammatory bowel disease

INTRODUCTION

The inflammatory bowel diseases (IBD) are chronic, idiopathic, inflammatory conditions of the gastrointestinal tract, that peak in incidence during the reproductive years. Therefore, the safety of IBD medications during pregnancy and lactation is of significant interest to patients. Unfortunately, the current pregnancy labeling used by the United States Food and Drug Association (FDA) is often misinterpreted and may mislead healthcare providers and their patients to believe that risk increases from Category A to B to C to D to X, which in fact, is not the case. In addition, the FDA categories do not always distinguish between risks based on human versus animal data, or between differences in frequency, severity, and type of fetal developmental toxicities.

AREAS COVERED

This article provides an in-depth review of the available safety data during pregnancy and lactation for the more potent immunosuppressants used to treat IBD: the immunomodulators and biologics. It also includes the authors' expert opinions on the use of these medications during these critical periods.

EXPERT OPINION

The benefit-to-risk ratio for most immunomodulators and biologics used in the treatment of IBD favors medication continuation during pregnancy. Certain immunomodulators, however, can cause extreme fetal harm and should be used with caution. While human safety data regarding teratogenesis and some data on pregnancy outcomes exist for most IBD medications, long-term follow-up studies of children and young adults exposed to these drugs in utero are lacking. These studies are needed to determine if these drugs are of sufficiently low risk to be considered safe.

Thalidomide Induces Apoptosis in Human Monocytes by Using a Cytochrome c-Dependent Pathway

Thalidomide has been shown to be an effective treatment in various immunologic diseases such as Crohn's disease and rheumatoid arthritis. Its major effect is thought to be mediated by the inhibition of TNF-alpha, but the exact mechanism of action is still uncertain. Recent observations could demonstrate that the induction of monocyte apoptosis is a common feature of a variety of anti-inflammatory agents. Therefore, we investigated the role of thalidomide on monocyte apoptosis. Treatment with thalidomide resulted in apoptosis of human peripheral blood monocytes in a time- and dose-dependent manner as demonstrated by annexin V staining. Monocyte apoptosis required the activation of caspases, as combined stimulation by thalidomide together with the broad caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone markedly prevented monocyte cell death. Apoptosis was triggered by a CD95/CD95 ligand, TNF-RI, and TRAIL-R1 independent pathway with an inhibition of AKT-1 kinase and consecutive mitochondrial release of cytochrome c, followed by the proteolytic activation of initiator caspase-9 and effector caspase-3. Our data suggest that thalidomide-induced monocyte apoptosis is at least partially mediated by a mitochondrial signaling pathway and might contribute to the complex immunomodulatory properties of the drug.

Bone marrow angiogenesis and progression in multiple myeloma: clinical significance and therapeutic approach

It is now well established that solid tumors depend on angiogenesis. Promoters and inhibitors of angiogenesis are in balance and antiangiogenic strategies aim at repressing the angiogenic process, thus retarding solid tumor progression. Recent data suggest the importance of angiogenesis in hematologic malignancies and several studies reveal an increased angiogenesis in active multiple myeloma. Angiogenesis seems to be a prominent feature of MM progression, and seems to be correlated with the prognosis and the resistance of MM to chemotherapy. Numerous cell populations and cytokines are involved in angiogenesis in multiple myeloma and antiangiogenic therapy with thalidomide is effective in patients with refractory or relapsed disease. The combination of thalidomide and of other immunomodulatory agents with other therapeutic regimens could lead to more effective management of patients with multiple myeloma.

Thalidomide for the treatment of recalcitrant oral Crohn's disease and orofacial granulomatosis

It has been suggested that thalidomide may be effective in the management of Crohn's disease, including the associated oral lesions. We detail the clinical response to low-dose thalidomide of 5 patients with clinical features of orofacial granulomatosis or oral Crohn's disease recalcitrant to recognized immunosuppressant therapy. All patients had clinical resolution of their symptoms and signs. Transient somnolence was the only reported adverse effect. Remission was maintained by extending the period between thalidomide doses. Thalidomide should be considered an effective therapy for the short-term treatment of severe orofacial granulomatosis in appropriately counseled patients.

Angiogenesis and chemokines in rheumatoid arthritis and other systemic inflammatory rheumatic diseases

Angiogenesis, the formation of new vessels, is important in the pathogenesis of rheumatoid arthritis (RA) and other inflammatory diseases. Chemotactic cytokines termed chemokines mediate the ingress of leukocytes, including neutrophils and monocytes into the inflamed synovium. In this review, authors discuss the role of the most important angiogenic factors and angiogenesis inhibitors, as well as relevant chemokines and chemokine receptors involved in chronic inflammatory rheumatic diseases. RA was chosen as a prototype to discuss these issues, as the majority of studies on the role of angiogenesis and chemokines in inflammatory diseases were carried out in arthritis. However, other systemic inflammatory (autoimmune) diseases including systemic lupus erythematosus (SLE), systemic sclerosis (SSc), Sjögren's syndrome (SS), mixed connective tissue disease (MCTD), polymyositis/dermatomyositis (PM/DM) and systemic vasculites are also discussed in this context. As a number of chemokines may also play a role in neovascularization, this issue is also described here. Apart from discussing the pathogenic role of angiogenesis and chemokines, authors also review the regulation of angiogenesis and chemokine production by other inflammatory mediators, as well as the important relevance of neovascularization and chemokines for antirheumatic intervention.

Doppler enhancement after intravenous levovist injection in Crohn's disease

Although transabdominal bowel sonography (TABS) has been proposed as a reliable tool to assess increased bowel wall thickness (BWT), the most common sonographic pattern in patients with Crohn's disease (CD), its accuracy is limited in the diagnosis of CD. We therefore tried to assess whether color Doppler enhancement with Levovist, a galactose-based intravenous sonographic contrast agent able to enhance the arterial Doppler signal, increases TABS accuracy. Thirty-one patients with ileal CD, diagnosed by endoscopy and enteroclysis, and 20 healthy volunteers were examined with conventional TABS. Color Doppler of the intramural enteric vessels was then performed before and after intravenous injection of Levovist. Twenty-two CD patients had a BWT >4 mm, and 16 of them presented with active disease. Two of the remaining nine CD patients, all with BWT <4 mm, presented with active disease. By means of color Doppler we identified six patients with inactive disease, normal BWT, and normal basal Doppler signal intensity, who showed an enhanced Doppler signal in intramural vessels after contrast agent bolus. Four of these patients, identified only by color Doppler after Levovist injection, relapsed within 6 months. In our experience, sensitivity and specificity of TABS, integrated with additional stimulated acoustic emission mode, were 96.7% and 100%, respectively. The use of Levovist in color Doppler increases the accuracy of TABS in CD diagnosis and follow-up.

Thalidomide treatment for refractory Crohn's disease: a review of the history, pharmacological mechanisms and clinical literature

Several recent case reports and clinical trials have demonstrated that thalidomide is emerging as an efficacious alternative in the treatment of selected patients with refractory Crohn's disease. The effects of thalidomide are at least partly mediated by down-regulation of tumour necrosis factor (TNF)-alpha, a potent proinflammatory cytokine. However, thalidomide is also known to inhibit angiogenesis, and it has several other well-described immunomodulatory properties. Clinical studies have confirmed that previously refractory Crohn's disease patients respond to thalidomide, and many enter clinical remission. Efficacy usually occurs within 4 weeks. Thalidomide also has steroid-sparing properties, and it is particularly useful in treating oral and fistulous complications of Crohn's disease. Although it is usually tolerable, careful monitoring is recommended to prevent toxicities, such as birth defects and peripheral neuropathy. This review provides a detailed summary of the literature to date on the use of thalidomide treatment for Crohn's disease. Special attention is directed towards its history, mechanisms, and proposed role. The recent development of thalidomide analogues is also discussed briefly.

Inflammatory bowel disease: immunodiagnostics, immunotherapeutics, and ecotherapeutics

Treatment options for inflammatory bowel disease (IBD) reflect a continuing shift from empiricism to strategies based on improved understanding of the pathophysiology of disease. In susceptible individuals, IBD appears to be the result of defective regulation of mucosal immune interactions with the enteric microflora. This has prompted research directed at the interface of the traditional disciplines of immunology, microbiology, and epithelial cell biology. Whereas immunodiagnostics have been of limited clinical value in IBD, assessments of mucosal rather than systemic immune function are promising. Therapeutically, there is an increasing trend toward more aggressive and earlier use of immunomodulatory agents, particularly for prevention of relapse, with cytokine manipulation as a bridge therapy to achieve remission in patients with acute severe disease. Although most drug treatments are directed toward altering the host response, the rationale for manipulating the enteric flora appears sound and will be the basis of additional future therapeutic strategies. Notwithstanding the widening range of options for drug therapy in IBD, other outcome modifiers and well-established principles of managing chronic disease are as important as ever.