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Pyometra, an infection of the uterus, can be a life-threatening disease in dogs. While the disease is well-known, we do not yet understand exactly how it develops. The AKC Canine Health Foundation (CHF) is a non-profit organization dedicated to advancing the health of all dogs and their owners by funding humane scientific research. The AKC CHF remains committed to the prevention, treatment, and cure of canine disease, including pyometra. CHF recently awarded funding through Grant 02669-A to researchers at the University of Veterinary Medicine of Vienna to study possible mechanisms of pyometra development.

Canine pyometra usually occurs during diestrus (also known as metestrus) in the 1-3 months following estrus. The bacteria E. coli is the most common infectious agent isolated from infected uteri. Lipid (fat) molecules are an easy target for infectious organisms like E. coli to use in their efforts to evade the host immune system.

Stages of the Canine Estrus Cycle

Proestrus The vulva swells and the female attracts males, but will usually not allow mounting.
Estrus Called “heat”, this is the mating period when ovulation occurs, and females attract and accept males.
Diestrus (Metestrus) Regression of the corpus luteum occurs, and the bitch is pregnant or in a resting phase.
Anestrus  A resting period.

Looking Ahead

Previous data showed an increased amount of lipid droplets in the uterine lining (endometrium) during diestrus. This, coupled with the above facts, prompted researchers to explore the correlation between lipid accumulation in endometrial epithelial cells and pyometra caused by E. coliThe investigators will examine healthy diestrus uterine tissue and pyometra-affected tissue to identify the lipid composition and lipid-associated proteins present. They will also assess any changes in the lipid composition or lipid droplet formation in these tissues in the face of bacterial infection.  

A better understanding of the role lipid metabolism plays in pyometra may lead to new treatment targets or improved treatment options for affected dogs. Reproductive research studies like this are only part of CHF’s robust portfolio. Research topics include reproductive health, canine cancer, epilepsy, tick-borne disease, and more.  

Additional active AKCCHF reproductive medicine grants include: 

Learn more about CHF-funded research at 

This article is intended solely as general guidance, and does not constitute health or other professional advice. Individual situations and applicable laws vary by jurisdiction, and you are encouraged to obtain appropriate advice from qualified professionals in the applicable jurisdictions. We make no representations or warranties concerning any course of action taken by any person following or otherwise using the information offered or provided in this article, including any such information associated with and provided in connection with third-party products, and we will not be liable for any direct, indirect, consequential, special, exemplary or other damages that may result, including but not limited to economic loss, injury, illness or death.
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