VEGF increases the permeability of sheep pleura ex vivo through VEGFR2 stimulation.

Vascular endothelial growth factor (VEGF), a cytokine that increases vascular permeability to water and proteins and induces angiogenesis, has been implicated in the development of pleural effusions. Inflammatory and malignant pleural effusions are rich in VEGF content while mesothelial cells produce and excrete VEGF. In this report we aimed at investigating by means of electrophysiology the direct effects of VEGF on the parietal and visceral sheep pleura as well as the type of receptors that mediate this effect.

Spironolactone increases permeability of visceral sheep peritoneum.

Aldosterone is a key component of the renin-angiotensin-aldosterone system, and spironolactone, an aldosterone receptor blocker, shows beneficial effects in patients with end-stage renal disease and heart failure. The aim of the present study was to investigate by means of Ussing chamber technique the effect of spironolactone on the transmesothelial permeability of visceral sheep peritoneum in vitro. Peritoneal samples from the omentum of adult sheep were collected immediately after slaughter in a cooled and oxygenated Krebs-Ringer bicarbonate (KRB) solution.

Dexamethasone decreases the transmesothelial electrical resistance of the parietal and visceral pleura.

The effect of dexamethasone on the transmesothelial electrical resistance (R(TM)) of sheep pleura was investigated by Ussing chamber experiments. Our results show that dexamethasone decreases the R(TM) of sheep pleurae, in part by stimulation of glucocorticoid receptors. This finding may be of importance in regard to the faster resolution of corticosteroid-treated pleural effusions.

Rapid effect of dexamethasone on the permeability of visceral sheep peritoneum.

The peritoneal mesothelium is a biologic barrier to water and ion transport. Its functional and structural integrity is crucial for peritoneal dialysis treatment. In vivo studies have shown that corticosteroids increase transcellular water transport and ultrafiltration of the rat peritoneum.