Feline vaccine‐associated sarcomagenesis: Is there an inflammation‐independent role for aluminium?

Aluminium has been found in feline vaccine‐associated sarcomas. In this study, we investigated the potential for aluminium to contribute directly to tumourigenesis. Our results indicated that an aluminium hydroxide adjuvant preparation was cytotoxic and mutagenic in human‐Chinese hamster ovary (CHO) hybrid cells in vitro. Moreover, CHO cells deficient in DNA double strand break (DSB), but not single‐strand break (SSB), repair, were particularly sensitive to aluminium exposure compared with repair proficient cells, suggesting that aluminium is associated with DSBs. In contrast to CHO cells, primary feline skin fibroblasts were resistant to the cytotoxic effects of aluminium compounds and exposure to an aluminium chloride salt promoted cell growth and cell cycle progression at concentrations much less than those measured in particular feline rabies vaccines. These findings suggest that aluminium exposure may contribute, theoretically, to both initiation and promotion of tumours in the absence of an inflammatory response.     

Strongylus vulgaris associated with usage of selective therapy on Danish horse farms-Is it reemerging?

Nematodes belonging to the order Strongylida are ubiquitous in grazing horses, and the large strongyle Strongylus vulgaris is considered the most pathogenic. This parasite was originally described widely prevalent in equine establishments, but decades of frequent anthelmintic treatment appears to have reduced the prevalence dramatically. Increasing levels of anthelmintic resistance in cyathostomin parasites have led to implementation of selective therapy to reduce further development of resistance. It has been hypothesized that S. vulgaris could reoccur under these less intensive treatment circumstances. The aim with the present study was to evaluate the occurrence of S. vulgaris and the possible association with usage of selective therapy. A total of 42 horse farms in Denmark were evaluated for the presence of S. vulgaris using individual larval cultures. Farms were either using a selective therapy principle based on regular fecal egg counts from all horses, or they treated strategically without using fecal egg counts. A total of 662 horses were included in the study. Covariate information at the farm and horse level was collected using a questionnaire. The overall prevalence of S. vulgaris was 12.2% at the individual level and 64.3% at the farm level. Farms using selective therapy had horse and farm prevalences of 15.4% and 83.3%, respectively, while the corresponding results for farms not using selective therapy were 7.7% and 38.9%. These findings were found statistically significant at both the horse and the farm level. Stud farms using selective therapy were especially at risk, and occurrence of S. vulgaris was significantly associated with the most recent deworming occurring more than six months prior. The results suggest that a strict interpretation of the selective therapy regimen can be associated with an increased prevalence of S. vulgaris. This suggests that modifications of the parasite control programs could be considered on the studied farms, but it remains unknown to which extent this can be associated with increased health risks for infected horses.     

Prolactin – to be reconsidered in canine mammary tumourigenesis?

Mammary tumours represent the most common neoplastic disease of the female dog, and the incidence in female dogs is much higher than in women. Whereas the influence of sexual steroids on breast cancer (BC) development in dogs has been studied, very little is known about the role of prolactin (PRL). New studies show that until recently, the importance of PRL in human BC development and progression has been highly underestimated. PRL plays a role in promoting benign as well as malignant neoplastic cell growth in BC in vitro and in vivo. Sporadic publications proposed a tumour promotor role in the dog. The goal of this review is to summarize our knowledge about PRL and human BC as well as canine mammary tumourigenesis, and propose future research in this area.     

Peripheral blood abnormalities and bone marrow infiltration in canine large B‐cell lymphoma: is there a link?

Official guidelines do not consider bone marrow (BM) assessment mandatory in staging canine lymphoma unless blood cytopenias are present. The aim of this study was to find out if blood abnormalities can predict marrow involvement in canine large B‐cell lymphoma. BM infiltration was assessed via flow cytometry. No difference was found between dogs without haematological abnormalities and dogs with at least one. However, the degree of infiltration was significantly higher in dogs with thrombocytopenia, leucocytosis or lymphocytosis and was negatively correlated to platelet count and positively to blood infiltration. Our results suggest that blood abnormalities are not always predictive of marrow involvement, even if thrombocytopenia, leucocytosis or lymphocytosis could suggest a higher infiltration. BM evaluation should therefore be included in routine staging in order not to miss infiltrated samples and to improve classification. However, its clinical relevance and prognostic value are still not defined and further studies are needed.     

Primary cutaneous extragenital canine transmissible venereal tumour with Leishmania‐laden neoplastic cells: a further suggestion of histiocytic origin?

The clinical signs and histopathological features of a primary extragenital canine transmissible venereal tumour (TVT) are described. Three subcutaneous round alopecic nodules were located on the anterior and caudal dorsal region and in the ventral area of the neck. Cytologically, tumour cells were intermediate in size with a moderate amount of cytoplasm, and the nuclei were immature with finely reticular chromatin. The cytoplasm was lightly to heavily basophilic and contained distinct small vacuoles at the periphery. On the basis of these characteristics, a diagnosis of TVT was made and confirmed by histological and ultrastructural investigations. Leishmania amastigotes were detected in the cytoplasm of macrophages and neoplastic cells of the tumoral mass. The presence of the parasite within neoplastic cells is consistent with a histiocytic origin of TVT.     

An update on canine cardiomyopathies – is it all in the genes?

Dilated cardiomyopathy is the second most common cardiac disease in dogs and causes considerable morbidity and mortality. Primary dilated cardiomyopathy is suspected to be familial, and genetic loci have been associated with the disease in a number of breeds. Because it is an adult‐onset disease, usually with late onset, testing breeding dogs and bitches before breeding for a genetic mutation that could lead to dilated cardiomyopathy would be helpful to prevent disease. There is growing evidence that the genetic basis may be multigenic rather than monogenic in the majority of studied breeds. This review article describes the known genetic aspects of canine dilated cardiomyopathy and the implications of genetic tests on heart testing and the future of veterinary cardiology.     

Immunotherapy for canine cancer – Is it time to go back to the future?

Over the last 50 years, the significance of the immune system in the development and control of cancer has been much debated. However, recent discoveries provide evidence for a role of immunological mechanisms in the detection and destruction of cancer cells. Forty years ago veterinary oncologists were already investigating the feasibility of treating neoplasia by enhancing anticancer immunity. Unfortunately, this research was hindered by lack of a detailed understanding of cancer immunology, this limited the specificity and success of these early approaches. The great forward strides made in our understanding of onco‐immunology in recent years have provided the impetus for a resurgence of interest in anticancer immunotherapy for canine patients. In this article both these initial trials and the exciting novel immunotherapeutics currently in development are reviewed.