6 MUCIN TURNOVER

摘要

1 INTRODUCTION Protection at mucosal surfaces throughout the body have developed to maintain a constant and dynamic screen of the external environment. Many different processes are necessary to allow protection against all manner of agents which may cause damage, while enabling vital interactions required for normal survival. Recovery and transport of nutrients from the diet must be balanced against resistance to harmful chemicals, toxins and other potentially damaging molecules. At the same time, a constant communication with the microflora is needed to utilise those beneficial commensal strains while resisting pathogens. Provision of a milieu enabling the action of a range of antimicrobial molecules is also required. Thus, the mucosal protective barrier must be a dynamic system giving continuous defence while enabling normal and life supporting processes. Biomarkers for mucosal disease reflect the failure of the protective barrier at a variety of levels and underline its' multifactorial nature.