Publications

Patients with long-standing inflammatory bowel disease (IBD) colitis have a 2.4-fold higher risk of developing colorectal cancer (CRC) than the general population, for both ulcerative colitis (UC) and Crohn's disease (CD) colitis. Surveillance colonoscopy is recommended to detect early CRC and dysplasia. Most dysplasia discovered in patients with IBD is actually visible. Recently published SCENIC (Surveillance for Colorectal Endoscopic Neoplasia Detection and Management in Inflammatory Bowel Disease Patients: International Consensus Recommendations) consensus statements provide unifying recommendations for the optimal surveillance and management of dysplasia in IBD. SCENIC followed the prescribed processes for guideline development from the Institute of Medicine (USA), including systematic reviews, full synthesis of evidence and deliberations by panelists, and incorporation of the GRADE methodology. The new surveillance paradigm involves high-quality visual inspection of the mucosa, using chromoendoscopy and high-definition colonoscopy, with endoscopic recognition of colorectal dysplasia. Lesions are described according to a new classification, which replaces the term 'dysplasia associated lesion or mass (DALM)' and its derivatives. Targeted biopsies are subsequently done on areas suspicious for dysplasia, and resections are carried out for discrete, resectable lesions.

Serine-rich repeat glycoproteins are adhesins expressed by commensal and pathogenic Gram-positive bacteria. A subset of these adhesins, expressed by oral streptococci, binds sialylated glycans decorating human salivary mucin MG2/MUC7, and platelet glycoprotein GPIb. Specific sialoglycan targets were previously identified for the ligand-binding regions (BRs) of GspB and Hsa, two serine-rich repeat glycoproteins expressed by Streptococcus gordonii While GspB selectively binds sialyl-T antigen, Hsa displays broader specificity. Here we examine the binding properties of four additional BRs from Streptococcus sanguinis or Streptococcus mitis and characterize the molecular determinants of ligand selectivity and affinity. Each BR has two domains that are essential for sialoglycan binding by GspB. One domain is structurally similar to the glycan-binding module of mammalian Siglecs (sialic acid-binding immunoglobulin-like lectins), including an arginine residue that is critical for glycan recognition, and that resides within a novel, conserved YTRY motif. Despite low sequence similarity to GspB, one of the BRs selectively binds sialyl-T antigen. Although the other three BRs are highly similar to Hsa, each displayed a unique ligand repertoire, including differential recognition of sialyl Lewis antigens and sulfated glycans. These differences in glycan selectivity were closely associated with differential binding to salivary and platelet glycoproteins. Specificity of sialoglycan adherence is likely an evolving trait that may influence the propensity of streptococci expressing Siglec-like adhesins to cause infective endocarditis.