Hewicker-Trautwein, M. | bioRxiv Science

bioRxiv2020

The effect of ischaemic postconditioning on mucosal integrity and function in equine jejunal ischaemia

BackgroundIschaemic postconditioning (IPoC) has been shown to ameliorate ischaemia reperfusion injury in different species and tissues. ObjectivesTo assess the feasibility of IPoC in equine small intestinal ischaemia and to assess its effect on histomorphology, electrophysiology and paracellular permeability. Study designrandomized controlled terminal in vivo experiment MethodsExperimental jejunal ischaemia was induced for 90 min in horses under general anaesthesia. In the control group (C; n=7), the jejunum was reperfused without further intervention. In the postconditioning group (P; n=7), IPoC was implemented by clamping the mesenterial vessels after ischaemia. This was followed by 120 minutes of reperfusion in both groups. Intestinal microperfusion and oxygenation was measured during IPoC using spectrophotometry and Doppler fluxmetry. Histomorphology and histomorphometry of the intestinal mucosa were assessed. Furthermore, electrophysiological variables and unidirectional fluxrates of 3H-mannitol were determined in Ussing chambers. Western Blot analysis was performed to determine the tight junction protein levels of Claudin-1, Claudin-2 and Occludin in the intestinal mucosa. Comparisons between the groups and time points were performed using a two-way repeated measures ANOVA or non-parametric statistical tests for the ordinal and not normally distributed data (significance p<0.05). ResultsPostconditioning significantly reduced intestinal microperfusion during all clamping cycles, yet affected tissue oxygenation only during the first cycle. After reperfusion, group IPoC showed significantly less mucosal villus denudation (mean difference 21.5 %, p=0.02) and decreased mucosal-to-serosal fluxrates (mean difference 15.2 nM/cm2/h, p=0.007) compared to group C. There were no significant differences between the groups for the other tested variables. Main limitationssmall sample size, long term effects were not investigated. ConclusionsFollowing ischaemic postconditioning, the intestinal mucosa demonstrated significantly less villus denudation and paracellular permeability compared to the untreated control group, possibly indicating a protective effect of IPoC on ischaemia reperfusion injury.

pathology↗

bioRxiv2018

A de novo EDA-variant in a litter of shorthaired standard Dachshunds with X-linked hypohidrotic ectodermal dysplasia

In this study, we present a detailed phenotype description and genetic elucidation of the first case of X-linked hypohidrotic ectodermal dysplasia in the shorthaired standard Dachshund. This condition is characterized by partial alopecia, missing and malformed teeth and a lack of eccrine sweat glands. Clinical signs including dental X-raying and histopathological findings were consistent with an ectodermal dysplasia. Pedigree analysis supported an X-recessive mode of inheritance. Whole-genome sequencing of one affected puppy and his dam identified a 1-basepair deletion within the ectodysplasin-A gene (CM000039.3:g.54509504delT, PRJEB27789). Sanger sequencing of further family members confirmed the PRJEB27789-variant. Validation in all available family members, 37 unrelated shorthaired standard Dachshunds, 128 Dachshunds from all other breeds and samples from 34 dog breeds revealed the PRJEB27789 variant to be private for this family. Two heterozygous females showed very mild alopecia but normal dentition. Since the dam is demonstrably the only heterozygous animal in the ancestry of the affected animals, we assume that the PRJEB27789-variant arose in the germline of the granddam or in an early embryonic stage of the dam. In conclusion, we detected a very recent de-novo EDA mutation causing X-linked hypohidrotic ectodermal dysplasia in the shorthaired standard Dachshund.

genetics↗