Impairment of Electroneutral Na+Transport and Associated Down-Regulation of NHE3 Contributes to Diarrhea Following in vivo Challenge with Brachyspira spp.

Impairment of Electroneutral Na+Transport and Associated Down-Regulation of NHE3 Contributes to Diarrhea Following in vivo Challenge with Brachyspira spp. Am J Physiol Gastrointest Liver Physiol. 2019 Nov 25;: Authors: Enns CB, Keith BA, Challa N, Harding JCS, Loewen ME Abstract The effects of Brachyspira hyodysenteriae and Brachyspira hampsoniispirochetosis on Na+transport was assessed in the colon to determine its contribution to diarrheal disease, in pigs following experimental infection. Electrogenic and electroneutral Na+absorption was assessedin Ussing chambers by radiolabelled 22Na flux and pharmacological inhibitory studies. Basal radiolabelled 22Na flux experiments revealed that Jmswas significantly impairedin B. hyodysenteriaeand B. hampsonii diseased pigs. Inhibition of ENaC via amiloride did not significantly reduce electrogenic short-circuit current (Isc) in the proximal, apex, and distal colonic segments of diseased pigs over control pigs, suggesting that a loss of electroneutral Na+absorption is responsible for diarrheal development. These findings were further supportedby significant down-regulation of Na+/H+exchanger (NHE1, NHE2, andNHE3) mRNA expression in the proximal, apex and distal colonic segments paired with decreased protein expression of the critical NHE3 isoform. The decrease in NHE3 mRNA expression appears not to be attributed to the host's cytokine response as human IL-1α did not modify NHE3 mRNA express...
Source: Am J Physiol Gastroi... - Category: Gastroenterology Authors: Tags: Am J Physiol Gastrointest Liver Physiol Source Type: research