Progress on Gastric Torsion Mystery

This article is the latest information in exciting research that looks like it is finally cracking the mystery of gastric dilatation-volvulus (gastric torsion/bloat), at least in Great Danes.

Read the article here.

The Canine Health Foundation has funded this team to look into whether the situation is similar or not in German Shepherd Dogs. Here is their update as of the end of last year:

“The Genetics of Bloat in German Shepherd Dogs: The Roles of Immune System Genes and the Gut Microbiome” Principle Investigator: Michael Harkey, PhD; Fred Hutchinson Cancer Research Center

The investigators have recently shown a significant association of three immune genes with bloat in Great Danes. For each of the three genes, one allele (variant) is found at unusually high frequency in dogs that have been treated for bloat, and the presence of any one of these “risk” alleles triples the chance that the dog will experience bloat at some time in its life. The research team also showed that the bacterial population living in the gut (the gut microbiome) is altered in dogs with bloat, and in dogs that carry these “risk” alleles, which may predispose these dogs to bloat.

We have proposed that genetic tendency to bloat may be caused largely by certain “risk” variants of genes of the immune system. These genes are responsible for distinguishing foreign cells from “self”, and as such, regulate which bacterial species in the gut will survive and which will be targeted for destruction. So these genes regulate the so-called “gut microbiome”. We hypothesized that dogs with a particular set of immune gene variants will maintain an unhealthy microbiome that predisposes them to bloat. Our recent research has supported this hypothesis in Great Danes.

The purpose of the proposed research is to expand the genetic and microbiome analysis of bloat to German Shepherds. We proposed to repeat the genetic and microbiome analysis, described for Great Danes, in this group of German Shepherds. We plan to sequence the 3 immune genes, DLA88, DRB1, and TLR5, and determine if any variants associate with bloat. We will then analyze the gut microbiome profiles of 50 affected dogs and 50 controls to look for changes in the bacterial population that correlate with bloat.

We have preliminary data on the association of genetic variants with bloat. For the gene DLA88, so far no variants associate with bloat. The “Risk” variant of this gene, that associated with bloat in Great Danes, has not been seen in German Shepherds. That risk variant may be unique to Great Danes. However, in the DRB1 gene, our data shows a strong association of variant 1201 with bloat. This is the same variant that was identified in Great Danes as a “risk” variant. So DRB1:1201 may be a good genetic marker for bloat in a wide variety of breeds. In the TLR5 gene, one variant shows a slight protective effect, being associated with the healthy control group. This is a new variant that has not been previously reported in any dog. These results will become more solid as additional data is accumulated. Analysis of the gut microbiome in these dogs will begin in this next term.

We are hoping these researchers will be expanding into other breeds soon, and we will do what we can to include Deerhounds in the research. Stay tuned!