The colon mucus layers minimize the contact between the luminal flora and the epithelial cells, and defects in this barrier may lead to colonic inflammation. We now describe an ex vivo method for analysis of mucus properties in human colon and mouse small and large intestine. Intestinal explants were mounted in horizontal perfusion chambers. The mucus surface was visualized by adding charcoal p...

Secretion of bicarbonate into the adherent layer of mucus gel creates a pH gradient with a near-neutral pH at the epithelial surfaces in stomach and duodenum, providing the first line of mucosal protection against luminal acid. The continuous adherent mucus layer is also a barrier to luminal pepsin, thereby protecting the underlying mucosa from proteolytic digestion. In this article we review t...

The respiratory mucus is a very complex biological material, which possesses both flow and deformation rheological properties, characterized by non-linear and time-dependent viscoelasticity and physical properties of adhesiveness and wettability. Viscosity and elasticity are directly involved in the transport capacity of mucus, whereas wettability and adhesiveness contribute to the optimal inte...

In this study, the development of a model tracheal mucus with chemical composition and physical properties (bulk viscoelasticity and surface tension) matched to that of native tracheal mucus is described. The mucus mimetics (MMs) were formulated using components that are abundant in tracheal mucus (glycoproteins, proteins, lipids, ions, and water) at concentrations similar to those found native...

A new mathematical model of the transport of mucus and periciliary liquid (PCL) in the airways by cilia is presented. Mucus is represented by a linearly viscoelastic fluid, the mat of cilia is modelled as an 'active porous medium.' The propulsive effect of the cilia is modelled by a time-dependent force acting in a shear-thinned 'traction layer' between the mucus and the PCL. The effects of sur...

Mucus is secreted throughout the gastro-intestinal tract by a variety of specialised cells located in glands or in the surface epithelium. The prime func­ tion of the mucus layer is to protect the delicate underlying mucosa from dam­ age by potentially harmful agents in the lumen (such as digestive enzymes and bacteria) and by the mechanical forces associated with digestion and the pas­ sage of...

The airway epithelial surface liquid is generally considered to be composed of two layers, a periciliary layer and a continuous thick mucus layer moving in bulk. This view may not be appropriate for all areas of the lung. Our hypothesis, that mucus may form a discontinuous layer with dynamic attachments to the surface, is investigated using a culture system. We used live-cell confocal microscop...

T he continuous cycle of respiratory infections and lung inflammation is a hallmark of cystic fibrosis (CF) lung disease and plays a central role in respiratory failure that develops in end-stage disease. Effective mucociliary clearance is an essential mechanism in host defence against infection and requires a functional ‘‘two-layer’’ mucus clearance system composed of a periciliary liquid laye...