Recurrent venous thromboses, anti-cardiolipin antibodies and Crohn's disease

Fat of the Gut: Epithelial Phospholipids in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) comprise a distinct set of clinical symptoms resulting from chronic inflammation within the gastrointestinal (GI) tract. Despite the significant progress in understanding the etiology and development of treatment strategies, IBD remain incurable for thousands of patients. Metabolic deregulation is indicative of IBD, including substantial shifts in lipid metabolism. Recent data showed that changes in some phospholipids are very common in IBD patients. For instance, phosphatidylcholine (PC)/phosphatidylethanolamine (PE) and lysophosphatidylcholine (LPC)/PC ratios are associated with the severity of the inflammatory process. Composition of phospholipids also changes upon IBD towards an increase in arachidonic acid and a decrease in linoleic and a-linolenic acid levels. Moreover, an increase in certain phospholipid metabolites, such as lysophosphatidylcholine, sphingosine-1-phosphate and ceramide, can result in enhanced intestinal inflammation, malignancy, apoptosis or necroptosis. Because some phospholipids are associated with pathogenesis of IBD, they may provide a basis for new strategies to treat IBD. Current attempts are aimed at controlling phospholipid and fatty acid levels through the diet or via pharmacological manipulation of lipid metabolism.

Mitochondria-Derived Damage-Associated Molecular Patterns in Neurodegeneration

Inflammation is increasingly implicated in neurodegenerative disease pathology. As no acquired pathogen appears to drive this inflammation, the question of what does remains. Recent advances indicate damage-associated molecular pattern (DAMP) molecules, which are released by injured and dying cells, can cause specific inflammatory cascades. Inflammation, therefore, can be endogenously induced. Mitochondrial components induce inflammatory responses in several pathological conditions. Due to evidence such as this, a number of mitochondrial components, including mitochondrial DNA, have been labeled as DAMP molecules. In this review, we consider the contributions of mitochondrial-derived DAMPs to inflammation observed in neurodegenerative diseases.

Molecular mimicry of Aggregatibacter actinomycetemcomitans with beta2 glycoprotein I

INTRODUCTION

beta2-Glycoprotein I (beta 2GPI) is important in the suppression of coagulation, and antibodies against TLRVYK peptides on the beta 2GPI molecule are related to thrombosis. According to the Swiss-Prot database, Aggregatibacter actinomycetemcomitans leukotoxin c has sequences (SIRVYK) that are homologous to the TLRVYK peptides. The aim of this study was to investigate the effects of A. actinomycetemcomitans infection on the antibody response against SIRVYK peptides in patients with periodontitis.

METHODS

Serum immunoglobulin G (IgG) antibody and IgG subclass antibody titers against SIRVYK or TLRVYK peptides were measured by enzyme-linked immunosorbent assay in 46 patients with aggressive periodontitis (eight with localized disease, 38 with generalized disease), 28 patients with chronic periodontitis, and 20 periodontally healthy subjects. The presence of A. actinomycetemcomitans in plaque and saliva samples was determined using polymerase chain reaction.

RESULTS

The level of anti-SIRVYK antibodies was significantly higher in patients who were A. actinomycetemcomitans-positive than in A. actinomycetemcomitans-negative patients (P < 0.05) in the chronic periodontitis group. A similar trend was found in the antibody response to TLRVYK peptide; however, no statistically significant difference was seen between A. actinomycetemcomitans-positive and -negative patients. The A. actinomycetemcomitans-positive patients displayed significantly higher levels of anti-SIRVYK IgG2 and IgG3 antibodies than A. actinomycetemcomitans-negative patients (P < 0.05 and P < 0.05, respectively). The level of IgG2 was highest among the four IgG subclasses and it predominantly increased in patients who were A. actinomycetemcomitans-positive. Anti-TLRVYK antibody levels were significantly correlated with anti-SIRVYK IgG antibody levels.

CONCLUSION

The results suggest that A. actinomycetemcomitans infection may elicit anti-SIRVYK IgG antibodies and modify the anti-TLRVYK antibody response in patients with periodontitis by molecular mimicry with beta2GPI.

Crohn's disease complicated by granulomatous interstitial nephritis, choroidal neovascularization, and central retinal vein occlusion

Extraintestinal manifestations of Crohn's disease are common. Granulomas may occur in different tissues in Crohn's disease, although kidney granulomas are extremely rare. Although ocular complications of Crohn's disease are infrequent, most ocular manifestations include iritis, uveitis, episcleritis, scleritis, and conjunctivitis. Central retinal vein occlusion has been reported in a few patients with Crohn's disease. The choroidal neovascularization is related to inflammatory disorders such as panuveitis, sarcoidosis. We report a patient with Crohn's disease complicated by granulomatous interstitial nephritis, choroidal neovascularization, and central retinal vein occlusion.

Venous thrombosis in inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) have a threefold increased risk of venous thrombosis, a major cause of morbidity and mortality. Although the exact mechanism explaining the initiation of thrombosis remains unclear, it is likely to be a multifactorial process. Reported abnormalities include activation of markers of the coagulation cascade, disturbed fibrinolysis and the activation of platelets. The contribution of thrombophilic disorders such as factor V Leiden, prothrombin gene mutations and hyperhomocysteinaemia are discussed, but their role in thrombosis associated with IBD has remained unclear. Recent research has examined elevated CD40, P-selectin levels and tissue factor-bearing microvesicles in venous thrombosis, and the relevance of these observations to IBD is reviewed.

Beta-2-glycoprotein-I, infections, antiphospholipid syndrome and therapeutic considerations

Evidence supports the association between infectious agents, antiphospholipid syndrome (APS), and the presence of antiphospholipid antibodies and anti-beta2-glycoprotein-I (beta2GPI) antibodies. Several mechanisms have been proposed to explain the role of bacteria/viruses in induction of an autoimmune condition, such as molecular mimicry between structures of a pathogen and self antigen and bystander activation or bacterial/viral superantigens. Protein databases reveal high homologies between the beta2GPI-related synthetic peptides and infectious agents. Studies employing experimental APS models proved molecular mimicry between beta2GPI-related synthetic peptides, which serve as target epitopes for anti-beta2GPI Abs, and structures within bacteria, viruses (e.g., CMV), and tetanus toxoid. Any explanation of how microbial infections might induce APS must take into account the genetic predisposition. In this paper, we discuss the association of antiphospholipid antibodies, infectious states, and molecular mimicry as a proposed mechanism for development of APS.