Luteinizing Hormone Receptor Activation Induces Migration and Adhesion in Neoplastic Canine Lymphocytes

Posted on by Janet Boyd

Luteinizing hormone (LH) is secreted from the brain (pituitary) in sexually intact dogs to stimulate synthesis of estrogen and testosterone in females and males, respectively. However, LH is secreted at concentrations up to 20 times higher following gonad removal with spaying or castration because hormonal negative feedback is lost. Although LH is considered to be a reproductive hormone, there are dozens of non-reproductive tissues in dogs that contain receptors for LH including immune system cells, specifically lymphocytes.

Lymphoma is a common malignant cancer of dogs involving lymphocytes, and spayed/castrated dogs are reportedly 3-4 times more likely to develop lymphoma. Conventional chemotherapy results in remission in approximately 60-90% of cases with a median survival time of 6-12 months. Preliminary work has identified LH receptors in canine lymphoma tissue and demonstrated LH- receptor-induced proliferation of neoplastic lymphocytes in vitro.

This study aims to determine if LH receptor activation induces adhesion and migration of neoplastic lymphocytes in vitro. Characterizing the role of LH receptor in neoplastic lymphocyte proliferation may help guide future lymphoma treatment options.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02751-A

RESEARCHERS

Michelle Kutzler, DVM, PhD; Oregon State University
Amount: $3,000

Disease Risks Associated with Spay and Neuter: A Breed-Specific, Gender Specific

Posted on by Janet Boyd

This study extends the investigator’s recently completed AKC Canine Health Foundation-funded project studying 12 dog breeds to identify major differences in the degree to which spay or neuter may be related to an increase in joint disorders (hip dysplasia; cranial cruciate ligament tear) and/or cancers (lymphoma; hemangiosarcoma; and mast cell tumor).

The original breeds studied were: Labrador Retriever, Golden Retriever, German Shepherd Dog, Rottweiler, Boxer, Bulldog, Doberman Pinscher, Dachshund, Corgi (both breeds), Chihuahua, Yorkshire Terrier and Shih Tzu. Findings did not associate an increase in disease association in the small breeds with spaying or neutering, while in larger breeds disease risk was dependent upon gender, and whether the spay or neuter procedure was performed before or after one year of age (Hart, B.L., L.A. Hart, A.P. Thigpen and N. H. Willits. 2014. Long-term health effects of neutering dogs: Comparison of Labrador Retrievers and Golden Retrievers. PLoS ONE 9(7): 10.1371/journal.pone.0102241).

In this second phase, the following breeds have been added to the study: Great Dane, Australian Shepherd, Bernese Mountain Dog, Cocker Spaniel, Border Collie, Beagle, St. Bernard, Irish Wolfhound, Jack Russell Terrier, Pug, Maltese, Pomeranian, Miniature Schnauzer, Boston Terrier, Australian Cattle Dog, Shetland Sheepdog, English Springer Spaniel, Cavalier King Charles Spaniel, and West Highland White Terrier. Upon completion of the study, the major publisher, Wiley, has agreed to place the total data set of all 31 breeds on an open access website as a resource for breeders, dogs owners, researchers and veterinarians.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02275

RESEARCHERS

Dr. Benjamin L Hart, DVM, PhD
University of California, Davis
Amount: $3,000 in 2016 with an additional $2,000 in 2017

Health Implications of Early Spay/Neuter on Canine Health

Posted on by PWDF Admin

Most dogs in the United States are spayed or neutered, and the default recommendation has been to perform these elective surgeries prior to physical maturity. However, recent data suggest that early spay and neuter may adversely impact the health and well-being of dogs.

In preliminary studies funded by CHF, Dr. Ben Hart of the UC Davis College of Veterinary Medicine found that early spay or neuter, prior to 12 months of age, was related to a significant increase in risk in five diseases of concern: hip dysplasia; cranial cruciate ligament tear; lymphosarcoma; hemangiosarcoma; and mast cell tumor.

CHF has now funded the second phase of Dr. Hart’s research in which he will expand his work to consider breed differences in vulnerability to joint disorders and risks of various cancers after early or late spay/neuter. Breeds considered will include: Labrador Retrievers, German Shepherd Dogs, and Dachshunds. Rottweilers, Chihuahuas, Standard Poodles, and Miniature Poodles will be included if resources and patient data are available. The expectation is that by inclusion of multiple breeds in phase II Dr. Hart will be able to develop a generalized understanding of the impact of early spay and neuter on disease risk in dogs. This in turn will enable veterinarians and breeders to make data-driven recommendations regarding timing of spay/neuter procedures to reduce the risk of development of multiple devastating diseases.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 1840

Related News

Long-Term Health Effects of Neutering Dogs: Comparison of Labrador Retrievers with Golden Retrievers

RESEARCHERS

Dr. Benjamin L Hart, DVM, PhD
University of California, Davis