Role of PGE2 in colonic motility: PGE2 attenuates spontaneous contractions of circular smooth muscle via EP4 receptors in the rat colon

Alterations of Prostanoid Expression and Intestinal Epithelial Barrier Functions in Ileus

INTRODUCTION

Intestinal manipulation (IM)-induced inflammation could contribute to postoperative ileus (POI) pathophysiology via the modulation of prostanoid pathways. To identify the prostanoids involved, we aimed to characterize the profile of prostanoids and their synthesis enzyme expression in a murine model of POI and to determine whether the altered prostanoids could contribute to POI.

METHODS

Four or 14 h after IM in mice, gastrointestinal (GI) motility and intestinal epithelial barrier (IEB) permeability were assessed in vivo and ex vivo in Ussing chambers. Using high sensitivity liquid chromatography-tandem mass spectrometry, we characterized the tissue profile of polyunsaturated fatty acid metabolites in our experimental model. Finally, we evaluated in vivo the effects of the prostanoids studied upon IM-induced gut dysfunctions.

RESULTS

We first showed that 14 h after IM was significantly faster than jejunal transit at 4 h post-IM, although it remained significantly increased compared to the control. In contrast, we showed that IM-induced inflammation increase in jejunum permeability was similar after four and 14 h. We next showed that expression of prostacyclin synthase and hemopoietic prostaglandin-D synthase mRNA and their products were significantly reduced 14 h after IM as compared to controls. Furthermore, 15-deoxy-delta 12,14-Prostaglandin J2 reduced the IM-induced inflammation increase in IEB permeability but had no effect on GI motility. In contrast, PGI2 increased IM-induced IEB permeability and motility dysfunctions.

CONCLUSIONS

Arachidonic acid derivative contributes differentially to GI dysfunction in POI. The decrease of 15-deoxy-delta 12,14-Prostaglandin J2 levels induced by IM could contribute to impaired GI dysfunctions in POI and could be considered as putative therapeutic targets to restore barrier dysfunctions associated with POI.

Adverse effect of FTY720P on colonic Na+ /K+ ATPase is mediated via ERK, p38MAPK, PKC, and PI3K

FTY720P, an analogue of sphingosine 1-phosphate, has emerged lately as a potential causative agent of inflammatory bowel disease, in which electrolytes movements driven by the sodium gradient established by the Na⁺ /K⁺ ATPase are altered. We showed previously in Caco-2 cells, a 50% FTY720P-induced decrease in the ATPase activity, mediated via S1PR2 and PGE2. This work aims at delineating the mechanism underlying PGE2 release and at investigating if the ATPase inhibition is due to changes in its abundance. The activity of the ATPase and the localization of a GFP-tagged Na⁺ /K⁺ -ATPase α₁ -subunit were assessed in cells treated with 7.5 nM FTY720P. The involvement of ERK, p38 MAPK, PKC, and PI3K was studied in cells treated with 7.5 nM FTY720P or 1 nM PGE2 in presence of their inhibitors, or by determining changes in the protein expression of their activated phosphorylated forms. Imaging data showed ∼30% reduction in the GFP-tagged Na⁺ /K⁺ ATPase at the plasma membrane. Both FTY720P and PGE2 showed, respectively, 50% and 60% reduction in ATPase activity that disappeared when p38 MAPK, PKC, and PI3K were inhibited individually but not with ERK inhibition. The effect of FTY720P was imitated by PMA, an activator of PKC. Western blotting revealed inhibition of ERK by FTY720P. It was concluded that FTY720P, through activation of S1PR2, downregulates the Na⁺ /K⁺ ATPase by inhibiting ERK, which in turn activates p38 MAPK leading to the sequential activation of PKC and PI3K, PGE2 release, and a decrease in the Na⁺ /K⁺ ATPase activity and membrane abundance.

Varicella-zoster virus infection and autonomic dysfunction

BACKGROUND AND PURPOSE

Autonomic dysfunction has been occasionally described in varicella-zoster virus (VZV) infection, while few systematic reviews are available. We systematically review autonomic dysfunction due to VZV infection.

METHODS

This study followed the PRISMA guideline, and three databases were researched and included cross-sectional studies in full-length publications in the English language using appropriate search keywords.

RESULTS

A total of 102 articles were identified initially; finally 45 studies were used for review, comprising pupillomotor dysfunction in 4, sudomotor dysfunction in 2, cardiovascular dysfunction in 2, gastrointestinal dysfunction in 14, and urogenital dysfunction in 23. They can be summarized as (1) VZV infection rarely produces orthostatic hypotension, which involves diffuse sympathetic dysfunction by polyneuropathy. (2) In contrast, VZV infection produces dysfunction of the bladder and the bowel, which involves segmental parasympathetic or sympathetic dysfunction by dorsal root ganglionopathy.

CONCLUSIONS

Awareness of VZV-related autonomic dysfunction is important, because such patients may first visit a gastroenterology or urology clinic. Close collaboration among neurologists, dermatologists, gastroenterologists, and urologists is important to start early antiviral agents and maximize bowel and bladder care in such patients.