Intestinal filtration-secretion due to increased intraluminal pressure in rabbits

Abstract

The mechanism of changes in small intestinal transport due to acutely increased intraluminal hydrostatic pressure (IHP) was investigated in detail using perfused in vivo rabbit intestinal segments. IHP affected passive transport in vivo by increasing effective mucosal surface area in the small intestine (indicated by 3HOH transport and tissue architectural changes) and increasing small intestinal permeability (indicated by a proportionately greater increase in mannitol than erythritol secretory clearance). IHP did not alter ileal blood flow rate measured by radioactive microspheres, despite grossly evident venous dilatation, or active intestinal transport in the ileum as measured by a) in vitro ion transport in the absence of elevated hydrostatic pressure, b) mucosal adenylate cyclase or Na-K-ATPase activities, and c) glucose-stimulated water and electrolyte absorption. Acutely increased IHP appears to influence the hydrodynamics of the mucosal microcirculation in the rabbit ileum to produce a driving force for passive filtration-secretion, which is associated with and possibly augmented by increased tissue permeability and effective surface area.

Use of an extracorporeal circuit to evaluate effects of intraluminal distention and decompression on the equine jejunum

“…Intestinal distention created by elevating the intestinal luminal perfusate outflow cannula has been used to create high intraluminal pressures. 47,48 We confirmed that this method resulted in the desired pressure by directly measuring intraluminal pressure in the outflow cannula via a 3-way stopcock connected to a pressure transducer. Similar to results of previous studies, 8,[49][50][51] we also detected a single increase in intraluminal pressure after distention.…”

“…32 Increases in permeability have been reported following intraluminal distention of the intestine of various species, including horses. 7,15,47 Distention to an intraluminal pressure of 30 cm H 2 O causes multifocal areas of necrosis in the mucosa of rabbits. 47 However, results of a study evaluating equine jejunum revealed that although blood flow is reduced during distention, the effect is more accentuated in the serosa than the mucosa and submucosa.…”

Intestinal Ileus as a Possible Cause of Hypobicarbonatemia

“…An increase in net chloride reabsorption, however, is also predicted from the mode of operation of the Cl -/HCO 3 exchanger. Experimental work has shown that when intraluminal pressure is increased, the driving forces for filtration secretion are augmented [8,9,10]. Further, active solute transport mechanisms may be impaired in patients with ileus, as it has been shown experimentally when intraluminal pressures are increased [7,8].…”

Intra‐abdominal abscess in a patient with tumour necrosis factor receptor‐associated periodic syndrome

“…The effect of TNF‐ α , on disrupting tight junctions in the intestinal epithelium [15] and on increasing tight junction permeability in intestinal epithelial cells, is mediated through activation of NF‐ κ B [16]. An increase in intestinal permeability, caused by a rise in the intestinal intraluminal pressure, has also been reported in animal models of in vivo rabbit intestinal segments [17]. TRAPS is characterized by periodically occurring inflammation, believed to be due, in part, to inappropriately functioning TNFRSF1A and subsequent prolonged action of TNF‐ α .…”