Vicki L. Wilke

Thyroid Cancer in Dogs: An Update Based on 638 Cases (1995–2005)

The goal of this study was to update the descriptive statistics of thyroid cancer by using data from multiple institutions collected through the Veterinary Medical Database (VMDB). Information was collected and reported from cases of canine thyroid cancer submitted to the VMDB between January 1, 1995 and December 31, 2005. Odds ratio (OR) analysis was performed on breeds that had > or =3% of the total number of dogs with thyroid cancer; ORs for each age category were also determined. Thyroid cancer represented 1.1% of all neoplasms during the time period of interest. Golden retrievers, beagles, and Siberian huskies all had significantly increased ORs for developing thyroid cancer. No sex predisposition was evident, but dogs between 10 and 15 years of age had a significantly increased chance of developing thyroid disease. Carcinomas and adenocarcinomas represented 90% of thyroid cancers, while adenomas represented 9.3%. Thyroid carcinoma and adenocarcinoma continue to be uncommon in our canine population. Older dogs are still more commonly affected, and this study is in agreement with previous studies that golden retrievers and beagles are overrepresented. A new finding is that Siberian huskies are also overrepresented. Carcinomas represent a much higher proportion of thyroid cancers than previously reported, and adenomas are likely incidental findings on necropsy. Thyroid cancer should be high on the list of differentials for a neck mass in older, large-breed dogs, as they make up 1.1% of the cancer cases reported. The overwhelming majority of thyroid cancers are carcinomas, and they are most common in golden retrievers, beagles, and Siberian huskies.

Short-term and long-term outcomes for overweight dogs with cranial cruciate ligament rupture treated surgically or nonsurgically

OBJECTIVE To determine short- and long-term rates of successful outcomes of surgical and nonsurgical treatments for overweight dogs with cranial cruciate ligament rupture (CCLR). DESIGN Prospective, randomized, clinical trial. Animals-40 client-owned overweight dogs with unilateral CCLR. PROCEDURES Dogs were randomly assigned to nonsurgical (physical therapy, weight loss, and NSAID administration) or surgical (tibial plateau leveling osteotomy) treatment groups; dogs in both groups received the same nonsurgical treatments. Dogs were evaluated immediately before and 6, 12, 24, and 52 weeks after initiation of treatments via owner questionnaires, gait analysis, and dual-energy x-ray absorptiometry. A successful outcome was defined as an affected limb net ground reaction force > 85% of the value for healthy dogs and a ≥ 10% improvement in values of questionnaire variables. RESULTS Owner questionnaire responses indicated dogs in both groups improved during the study, but dogs in the surgical treatment group seemed to have greater improvement. Body fat percentages for dogs in both treatment groups significantly decreased during the study. Surgical treatment group dogs had significantly higher peak vertical force for affected limbs versus nonsurgical treatment group dogs at the 24- and 52-week evaluation times. Surgical treatment group dogs had a higher probability of a successful outcome (67.7%, 92.6%, and 75.0% for 12-, 24-, and 52-week evaluations, respectively) versus nonsurgical treatment group dogs (47.1%, 33.3%, and 63.6% for 12-, 24-, and 52-week evaluations, respectively). CONCLUSIONS AND CLINICAL RELEVANCE Overweight dogs with CCLR treated via surgical and nonsurgical methods had better outcomes than dogs treated via nonsurgical methods alone. However, almost two-thirds of the dogs in the nonsurgical treatment group had a successful outcome at the 52-week evaluation time.

Inflammation, Apoptosis, and Necrosis Induced by Neoadjuvant Fas Ligand Gene Therapy Improves Survival of Dogs With Spontaneous Bone Cancer

Fas ligand (FasL) gene therapy for cancer has shown promise in rodents; however, its efficacy in higher mammals remains unknown. Here, we used intratumoral FasL gene therapy delivered in an adenovirus vector (Ad-FasL) as neoadjuvant to standard of care in 56 dogs with osteosarcoma. Tumors from treated dogs had greater inflammation, necrosis, apoptosis, and fibrosis at day 10 (amputation) compared to pretreatment biopsies or to tumors from dogs that did not receive Ad-FasL. Survival improvement was apparent in dogs with inflammation or lymphocyte-infiltration scores >1 (in a 3-point scale), as well as in dogs that had apoptosis scores in the top 50th percentile (determined by cleaved caspase-3). Survival was no different than that expected from standard of care alone in dogs with inflammation scores ≤1 or apoptosis scores in the bottom 50th percentile. Reduced Fas expression by tumor cells was associated with prognostically advantageous inflammation, and this was seen only in dogs that received Ad-FasL. Together, the data suggest that Ad-FasL gene therapy improves survival in a subset of large animals with naturally occurring tumors, and that at least in some tumor types like osteosarcoma, it is most effective when tumor cells fail to express Fas.Fas ligand (FasL) gene therapy for cancer has shown promise in rodents; however, its efficacy in higher mammals remains unknown. Here, we used intratumoral FasL gene therapy delivered in an adenovirus vector (Ad-FasL) as neoadjuvant to standard of care in 56 dogs with osteosarcoma. Tumors from treated dogs had greater inflammation, necrosis, apoptosis, and fibrosis at day 10 (amputation) compared to pretreatment biopsies or to tumors from dogs that did not receive Ad-FasL. Survival improvement was apparent in dogs with inflammation or lymphocyte-infiltration scores >1 (in a 3-point scale), as well as in dogs that had apoptosis scores in the top 50th percentile (determined by cleaved caspase-3). Survival was no different than that expected from standard of care alone in dogs with inflammation scores ≤1 or apoptosis scores in the bottom 50th percentile. Reduced Fas expression by tumor cells was associated with prognostically advantageous inflammation, and this was seen only in dogs that received Ad-FasL. Together, the data suggest that Ad-FasL gene therapy improves survival in a subset of large animals with naturally occurring tumors, and that at least in some tumor types like osteosarcoma, it is most effective when tumor cells fail to express Fas.

Identification of chromosomal regions associated with cranial cruciate ligament rupture in a population of Newfoundlands

OBJECTIVE To identify chromosomal regions associated with cranial cruciate ligament rupture (CCLR) in a population of Newfoundlands. ANIMALS 90 client-owned Newfoundlands. PROCEDURES A pedigree was constructed for dogs that did or did not have CCLR (determined on the basis of physical examination and radiographic findings). From this pedigree, affected and unaffected dogs were selected for genotyping on the basis of their predicted statistical likelihood of being homozygous CCLR-unaffected (n = 53) or homozygous CCLR-affected (37) dogs. Genotyping was performed for 532 microsatellite markers (MSATs). Comparisons of genotypes and allele frequencies were made between CCLR-affected and CCLR-unaffected dogs. RESULTS In the selected population, 495 MSATs were informative with a mean interval between markers of 5.5 centimorgans. Eighty-six MSATs were significantly associated with the CCLR trait, whereas 4 markers (located on 4 chromosomes) were significantly associated with the trait when false discovery rate (q value) was controlled at the 0.05 level. Subsequent initial validation confirmed significant trait association for 3 of the 4 MSATs. CONCLUSIONS AND CLINICAL RELEVANCE In the population of Newfoundlands, 4 MSATs that were located on 4 chromosomes were significantly associated with the CCLR trait. Three of those markers were validated in part via genotyping additional closely located markers. The MSATs that were associated with the CCLR trait were identified in all regions (except for those on chromosome 24). Newfoundlands with CCLR could be used to study the disease process associated with anterior cruciate ligament injuries that occur in young female human athletes.

Gene expression in intestinal mucosal biopsy specimens obtained from dogs with chronic enteropathy

OBJECTIVE To characterize mucosal gene expression in dogs with chronic enteropathy (CE). ANIMALS 18 dogs with CE and 6 healthy control dogs. PROCEDURES Small intestinal mucosal biopsy specimens were endoscopically obtained from dogs. Disease severity in dogs with CE was determined via inflammatory bowel index scores and histologic grading of biopsy specimens. Total RNA was extracted from biopsy specimens and microchip array analysis (approx 43,000 probe sets) and quantitative reverse transcriptase PCR assays were performed. RESULTS 1,875 genes were differentially expressed between dogs with CE and healthy control dogs; 1,582 (85%) genes were downregulated in dogs with CE, including neurotensin, fatty acid-binding protein 6, fatty acid synthase, aldehyde dehydrogenase 1 family member B1, metallothionein, and claudin 8, whereas few genes were upregulated in dogs with CE, including genes encoding products involved in extracellular matrix degradation (matrix metallopeptidases 1, 3, and 13), inflammation (tumor necrosis factor, interleukin-8, peroxisome proliferator-activated receptor γ, and S100 calcium-binding protein G), iron transport (solute carrier family 40 member 1), and immunity (CD96 and carcinoembryonic antigen-related cell adhesion molecule [CEACAM] 18). Dogs with CE and protein-losing enteropathy had the greatest number of differentially expressed genes. Results of quantitative reverse transcriptase PCR assay for select genes were similar to those for microchip array analysis. CONCLUSIONS AND CLINICAL RELEVANCE Expression of genes encoding products regulating mucosal inflammation was altered in dogs with CE and varied with disease severity. Impact for Human Medicine-Molecular pathogenesis of CE in dogs may be similar to that in humans with inflammatory bowel disease.

Serum cortisol concentration and force plate analysis in the assessment of pain associated with sodium urate-induced acute synovitis in dogs.

OBJECTIVE To determine the relationship between serum cortisol concentration and pain severity as measured by force platform gait analysis in dogs with experimentally induced synovitis of the stifle joint. ANIMALS 10 healthy hound-type dogs. PROCEDURES Dogs underwent 2 study phases. In the first phase, serum cortisol concentration, systolic arterial blood pressure, heart rate, and gait data were obtained at 0 (first sample), 2.5, 5, 7.5, and 10 hours. In the second phase, the same data were gathered immediately before (0 hours) and 2.5, 5, 7.5, and 10 hours after induction of acute urate synovitis in the left stifle joint. Data were statistically evaluated to compare changes in variable values over time and to determine the accuracy of serum cortisol measurements for diagnosis of acute orthopedic pain. RESULTS Following induction of synovitis, ground reaction forces were significantly decreased relative to preinduction values at 2.5, 5.0, 7.5, and 10.0 hours and serum cortisol concentration was significantly increased at 2.5 hours. A cortisol concentration of >or= 1.6 microg/dL indicated pain with a 91% sensitivity and 35% specificity. CONCLUSIONS AND CLINICAL RELEVANCE In this model, cortisol concentration may be useful for diagnosing pain in dogs. Although, with a cutoff of >or= 1.6 microg/dL, pain would be detected in most dogs with pain, some pain-free dogs would also be identified as having pain. Conversely, dogs with a serum cortisol of < 1.6 microg/dL would be unlikely to have pain. Validation of this diagnostic test in a large, heterogeneous group of clinical patients is necessary.

Gene expression profiling demonstrates differential expression of osteopontin in follicular thyroid carcinomas compared to normal thyroid tissue in dogs

Follicular thyroid carcinoma (FTC) is an aggressive tumour in dogs with little known about its molecular pathogenesis. The overall goal of this study was to examine FTC and normal thyroid tissue gene expression. Microarray analysis was performed on a pilot group of five FTC-affected dogs and four healthy dogs, and then osteopontin validated with quantitative polymerase chain reaction (PCR) and immunohistochemistry (IHC) of thyroid tissue from non-invasive FTC, invasive FTC and healthy dogs. On microarray analysis, 489 transcripts were differentially expressed between FTC and normal thyroid: 242 transcripts were down-regulated and 247 were up-regulated. Osteopontin expression was markedly increased in tumour tissue compared to normal thyroid tissue. Quantitative PCR and IHC confirmed differential expression of osteopontin in both tumour types (invasive and non-invasive) compared to normal thyroid tissue. There is justification for further investigation of osteopontin as a potential molecular marker for screening and monitoring of canine FTC.

Nasal Rhinosporidiosis in Two Dogs Native to the Upper Mississippi River Valley Region

Two dogs, 4 and 7 years of age, were presented for evaluation and treatment of excessive sneezing. Physical examinations in both cases were within acceptable limits except for the presence of a single mass in the left nasal passage in the first case and left-sided nasal discharge in the second case. Rhinoscopy was used to visualize the nasal masses, and in both cases a single mass was surgically removed. Impression smears and histopathology submitted from each mass revealed lymphoplasmacytic and neutrophilic inflammation with spores typical of Rhinosporidium seeberi. These are the first reported cases of nasal rhinosporidiosis in two dogs native to the Upper Mississippi River Valley area with no travel history outside the region.

MT1E and S100 Genes Provide Robust Discriminative Molecular Signatures of Intestinal Inflammation in Canine Inflammatory Bowel Disease

G A A b st ra ct s estimated by real-time PCR assay using oligonucleotide primers specific to immediate early gene. More than 10 copies/μg DNA of PCR amplicons were defined as positive. We compared the positive ratio of those colonoscopic findings of UC patients between positive and negative for CMV-DNA. Additionally, we examined the correlation between the number of CMVDNA amplicons [negative, low-copy group (10-100 copies/μg DNA), high-copy group (≧100 copies/μg DNA)], and colonoscopic features and their medications. Results: Positive ratio of ulcerative lesions was higher in CMV-DNA-positive group than in CMV-DNA-negative group [22/34 (64.7%) vs. 10/27 (37.0%), p<0.05]. Further analysis in limited to UC patients who had no ulcerative lesions revealed that the positive ratio of edema or redness in CMVDNA-positive groupwere significantly higher than in CMV-DNA-negative UC group [redness, 8/12 (66.7%) vs. 4/17 (23.5%); edema, 7/12 (58.3%) vs. 2/17 (11.8%)]. Moreover, the positive ratio of edema or redness is higher even in low-copy group of CMV-DNA-positive UC patients (Table). Ratio of UC patients treated with the combination of steroids and immunomodulators is significantly higher in the high-copy group than in other groups [negative, 3/27 (11.1%); low-copy group, 1/10 (10.0%); high-copy group, 11/24 (45.8%)]. Conclusions: In addition to ulcerative lesions, reddish and edematous colonic mucosa might be characteristic of early colonoscopic features in UC patients concomitant with CMV reactivation. CMV reactivation can be easily occurred in patients with UC refractory to the combined therapies of steroids and immunomodulators.