Prostatic Neoplasia in the Intact and Castrated Dog: How Dangerous is Castration?

Digital postprocessing analysis of prostatic perfusion in neutered dogs

B-mode ultrasound is routinely performed to evaluate the prostate gland in neutered dogs, although, the detection of malignancies may be challenging. Contrast-enhanced ultrasound (CEUS) has shown to be useful for the assessment of prostatic perfusion in normal and diseased dogs, although the interpretation of contrast ultrasonographic features may still be subjective. A quantitative tool for evaluating prostatic perfusion might improve the reliability of the results in terms of early detection of prostate neoplasia in neutered dogs. The present study aimed to evaluate the applicability of a postprocessing analysis tool to CEUS of the prostate in healthy neutered dogs, to provide quantitative measurements, and to study the influence of individual characteristics on prostatic regression. Twenty-three neutered dogs underwent a B-mode and CEUS examination of the prostate to acquire data about prostatic morphology and microcirculation. The prostate was imaged using a 5-7.5 MHz linear transducer and contrast was administered intravenously. Videoclips were analyzed by using Qontrast software and a postprocessing digital analysis tool (ImageJ) to measure perfusion peak intensity, time to peak, and vascularization ratio at the moment of the peak, which were then related to body weight, age, and time elapsed since orchiectomy. Correlation tests revealed higher vascularization in younger compared with older dogs (P < .05) and in smaller compared with larger dogs (P < .05). Time elapsed since orchiectomy (P > .05) did not affect prostatic perfusion. Contrast-enhanced ultrasound and the postprocessing analysis tool ImageJ allowed analysis of vascular perfusion in all dogs and have the potential to improve the diagnostic possibilities for andrological examination.

Anti-tumour effects of lapatinib on HER2-positive canine prostatic carcinoma cell lines

Background

Canine prostatic carcinoma (cPC) is a urogenital tumour with a poor prognosis, for which no effective treatment has been established. Recently, it has been shown that human epidermal growth factor receptor type 2 (HER2) is overexpressed in cPC cells; however, the efficacy of HER2-targeted therapy remains unclear.

Aim

Investigate the anti-tumour effect of lapatinib on HER2-positive cPC cell lines.

Methods

Two cell lines (muPC and bePC) were established from two dogs with cPC and the effects of lapatinib treatment on cell proliferation, apoptosis, and HER2 downstream signalling were investigated. Furthermore, muPC was used to generate tumour-bearing mice, and the anti-tumour effects of lapatinib were examined in vivo.

Results

Lapatinib treatment inhibited the proliferation and phosphorylation of Erk1/2 and Akt, which are downstream signals of HER2. Furthermore, the TUNEL assay showed that lapatinib induced apoptosis in both cell lines. The muPC-engrafted nude mouse model showed that lapatinib significantly inhibited tumour growth and increased the area of necrotic tumour tissue compared to the vehicle-treated groups.

Conclusion

Lapatinib exerts anti-tumour effects on cPC cells by inhibiting HER-2 signalling.

The reproductive microbiome in dogs: Friend or foe?

The microbiome of the reproductive tract is an area of research in full development. Specifically, the microbiome may be involved in reproductive health, disease, and pregnancy outcomes, as has been shown in humans and animals, including dogs. The aim of the present review was to summarize current knowledge on the microbiome of the canine reproductive tract, to expose the controversial role that some bacterial agents may play in canine subfertility, and to highlight future research perspectives. This review discussed whether the use of antimicrobials in dogs is appropriate to increase reproductive performance and to treat subfertility without proper diagnosis, and the possible use of probiotics to modulate the reproductive canine microbiome. Finally, we indicate areas in which scientific knowledge is currently lacking, and could be promising directions for future research.

Orexins and Prostate Cancer: State of the Art and Potential Experimental and Therapeutic Perspectives

Prostate cancer (PCa) is the second most common cancer in humans. Peptides have recently been used as targeted therapeutics in cancers, due to their extensive multi-functional applications. Two hypothalamic peptides, orexins A (OXA) and B (OXB) and their specific receptors, orexin receptor 1 (OX1R) and 2 (OX2R), orchestrate several biological processes in the central nervous system and peripheral organs. However, in addition to their role in physiological responses, orexins are involved in numerous inflammatory and/or neoplastic pathologies. The presence and expression of orexins in different cancer models, including prostate cancer, and their role in inducing pro- or anti-apoptotic responses in tumor cell lines, suggest that the orexinergic system might have potential therapeutic action or function as a diagnostic marker in PCa. In addition to the traditional animal models for studying human PCa, the canine model might also serve as an additional tool, due to its clinical similarities with human prostate cancer.

Chronic Use of Deslorelin in Dogs: Six Cases (2005-2022)

Deslorelin is currently registered for the induction of temporary infertility in male dogs, male cats, male ferrets, and also prepubertal female dogs, but research has shown its usefulness for other conditions requiring chronic treatment. This paper presents six cases of dogs chronically treated with deslorelin for indications such as benign prostatic hyperplasia, control of fertility, abnormal reproductive behavior and urinary incontinence. All animals were in good health during treatment. Treatment duration was 2-9 years. No short-term side effects were observed except for flare-up reactions, which were observed only in 1/4 intact males. Two dogs developed a neoplasia: a spayed bitch treated for urinary incontinence developed a pituitary carcinoma, and an intact male dog implanted for control of fertility developed a bladder carcinoma. While the pituitary carcinoma seems unlikely to be related to deslorelin, the bladder carcinoma could be due to the neutered condition of the dog (which was treated for 9 years) as urinary tract neoplasia is more common in dogs following gonadectomy. Chronic treatment with deslorelin is regarded as safe when an animal is being treated for life. The possibility that a pause in the treatment might be helpful for the animal should be investigated.

Prevalence of cesarean sections in swiss Bernese Mountain Dogs (2001-2020) and identification of risk factors

BACKGROUND

Dystocia is an important limiting factor in animal breeding due to its cost, stress for the mother and risk of death for the neonates. Assessment of incidence and characteristics of dystocia and the inherent risk of Cesarean section are of major importance. The aim of the present study was to evaluate the reproductive performance of Bernese Mountain Dogs in Switzerland, with a particular focus on the prevalence of Cesarean sections due to dystocia, and identification of possible risk factors.

RESULTS

The investigated population included 401 bitches, 207 sires, and 1127 litters. Litter size was significantly influenced by age and parity of the dam. Incidence of Cesarean section was 30.4%, with 2.0% of procedures being elective. History of previous Cesarean section, age of the dam, and a small litter size significantly influenced the risk for Cesarean section. The stillbirth rate was 12.0%, and the number of stillborn pups was significantly higher for litters delivered by Cesarean sections after birth of the first pup. The inbreeding coefficient had a low to non-significant impact on all reproductive parameters (e.g., litter size, number of stillborn pups).

CONCLUSION

The sample of Bernese Mountain Dogs of our study had an increased prevalence of Cesarean sections compared to the literature, and advanced age of the dam, litter size and prior Cesarean sections in the dam's reproductive history was identified as significantly influencing factors. In order to improve pups' survival rate, elective Cesarean section may be indicated in bitches that have had a previous Cesarean-section/s, are of advanced age, and/or have a small litter.

Diseases of the Canine Prostate Gland

In dogs, the most frequent diseases of the prostate gland are benign prostate gland hyperplasia (BPH), acute and chronic prostatitis, squamous metaplasia, and prostate tumors. New diagnostic tools comprise diagnostic markers in the blood and urine, as well as advanced imaging methods. The therapy can be initialized with the 5α-reductase-inhibitor finasteride or an anti-androgenic compound, and prolonged with a long-acting gonadotropin-releasing-hormone (GnRH)-agonist such as deslorelin. In case of prostatitis, effective antibiotics must be applied for weeks. Antibiotics must be able to penetrate into the prostate tissue; fluoroquinolones, clindamycin, and erythromycin are good choices and are in addition effective against mycoplasms. The chronical prostatitis cannot be differentiated from a neoplasia by sonography; a biopsy, histological, and bacteriological examination are required. Tumors of the prostate gland are seldom and mostly occur in castrated but in intact dogs. For the final diagnosis, a biopsy must be taken. Partial and total resection of the prostate gland by use of laser technique is possible but coincedes with many side effects and the prognosis is still futile. Immunotherapy combined with NSAIDs, targeted noninvasive thermotherapy, BRAF gene inhibitors, or prostate artery chemoembolization are promising methods.

A Review on Canine and Feline Prostate Pathology

Prostatic diseases are very common in male dogs, accounting for 3–10% of cases submitted to the veterinary practitioners. Commonly reported canine prostatic disorders include prostatic hyperplasia, prostatitis, prostatic cysts and prostatic carcinoma. However, clinical signs may be non-specific, or many cases are asymptomatic, thus leading to a difficult estimation of the actual prevalence of clinical cases. On the other side, because of the rare occurrence of prostate disease in cats, very little is known about pathogenesis, diagnostic approaches and treatment. The goal of this review is to provide detailed clinical and pathological overview of the feline and canine prostatic pathology, including the most up-to-date classification systems and histological findings. Emphasis is places on gross, cytological and histological features that are critical to reach a definitive diagnosis for a proper treatment and prognosis.

Comparative Pathobiology of Canine and Human Prostate Cancer: State of the Art and Future Directions

First described in 1817, prostate cancer is considered a complex neoplastic entity, and one of the main causes of death in men in the western world. In dogs, prostatic carcinoma (PC) exhibits undifferentiated morphology with different phenotypes, is hormonally independent of aggressive character, and has high rates of metastasis to different organs. Although in humans, the risk factors for tumor development are known, in dogs, this scenario is still unclear, especially regarding castration. Therefore, with the advent of molecular biology, studies were and are carried out with the aim of identifying the main molecular mechanisms and signaling pathways involved in the carcinogenesis and progression of canine PC, aiming to identify potential biomarkers for diagnosis, prognosis, and targeted treatment. However, there are extensive gaps to be filled, especially when considering the dog as experimental model for the study of this neoplasm in humans. Thus, due to the complexity of the subject, the objective of this review is to present the main pathobiological aspects of canine PC from a comparative point of view to the same neoplasm in the human species, addressing the historical context and current understanding in the scientific field.

Comparative pathology of dog and human prostate cancer

Though relatively rare in dogs, prostate cancer (PCa) is the most common non-cutaneous cancer in men. Human and canine prostate glands share many functional, anatomical and physiological features. Due to these similarities, canine PCa has been proposed as a model for PCa in men. PCa is typically androgen-dependent at diagnosis in men and for this reason, androgen deprivation therapies (ADT) are important treatments for advanced PCa in men. In contrast, there is some evidence that PCa is diagnosed more commonly in castrate dogs, at which point, limited therapeutic options are available. In men, a major limitation of current ADT is that progression to a lethal and incurable form of PCa, termed castrate-resistant prostate cancer (CRPC), is common. There is, therefore, an urgent need for a better understanding of the mechanism of PCa initiation and progression to CRPC to enable the development of novel therapeutic approaches. This review focuses on the functional, physiological, endocrine and histopathological similarities and differences in the prostate gland of these species. In particular, we focus on common physiological roles for androgen signalling in the prostate of men and dogs, we review the short- and longer-term effects of castration on PCa incidence and progression in the dog and relate how this knowledge may be relevant to understanding the mechanisms of CRPC in men.

An RNA-Seq-Based Framework for Characterizing Canine Prostate Cancer and Prioritizing Clinically Relevant Biomarker Candidate Genes

Prostate cancer (PCa) in dogs is a highly malignant disease akin to its human counterpart. In contrast to the situation in humans, multi-gene approaches facilitating risk stratification of canine PCa are barely established. The aims of this study were the characterization of the transcriptional landscape of canine PCa and the identification of diagnostic, prognostic and/or therapeutic biomarkers through a multi-step screening approach. RNA-Sequencing of ten malignant tissues and fine-needle aspirations (FNA), and 14 nonmalignant tissues and FNAs was performed to find differentially expressed genes (DEGs) and deregulated pathways. The 4098 observed DEGs were involved in 49 pathways. These 49 pathways could be grouped into five superpathways summarizing the hallmarks of canine PCa: (i) inflammatory response and cytokines; (ii) regulation of the immune system and cell death; (iii) cell surface and PI3K signaling; (iv) cell cycle; and (v) phagosome and autophagy. Among the highly deregulated, moderately to strongly expressed DEGs that were members of one or more superpathways, 169 DEGs were listed in relevant databases and/or the literature and included members of the PCa pathway, oncogenes, prostate-specific genes, and druggable genes. These genes are novel and promising candidate diagnostic, prognostic and/or therapeutic canine PCa biomarkers.

Intra- and Inter-observer Variability of Computed Tomographic Measurements of the Prostate Gland in Neutered Dogs

The purpose of this study was to evaluate the intra- and inter-observer variability of computed tomographic measurements of linear prostate dimensions in neutered dogs without signs of prostatic disease, to determine potential associations between prostatic parameters and body weight or age and to provide reference ranges. Length, width and height of the prostate gland were measured in 62 neutered dogs with no signs of prostatic disease by three observers with different levels of training. Statistically significant positive associations were found between all prostatic parameters and body weight and between all prostatic parameters and age at castration, but not with age. Formulae allowing the calculation of the expected values for prostatic parameters based on body weight are provided [length = 15.3 + body weight (BW) × 0.3; height = 9.7 + BW × 0.16; width = 9.5 + BW × 0.2]. These may represent a useful tool for computed tomographic evaluation of the size of the prostate in neutered dogs. Subjective evaluations of the morphological appearance of the prostate gland are also provided.

MicroRNA and vascular endothelial growth factor (VEGF) as new useful markers in the diagnosis of benign prostatic hyperplasia in dogs

Numerous specific biomarkers with a prognostic and diagnostic value comparable to histopathological findings are now used for non-invasive diagnosis of prostate diseases in humans. Meanwhile, as far as dogs are concerned, the diagnosis of prostate disorders is based solely on clinical examination and ultrasound (USG). Therefore, the aim of the study was to assess the usefulness of two biomarkers, i.e. miRNA-129 and VEGF for the diagnosis of BPH in dogs. The study involved 40 dogs divided into three groups. Group I (n = 9) comprised healthy dogs up to the age of 5 years, Group II (n = 17) comprised dogs between the ages of 5-10 suffering from BPH as confirmed by the examination and Group III (n = 14) comprising dogs over 10 years of age, which also had BPH confirmed. The results demonstrated that dogs in group II and III exhibited a significant decrease in miRNA expression (P < 0.0001) and a significant increase in serum VEGF levels (P = 0.025) when compared to the dogs in group I. There was also a positive correlation between the prostate size and VEGF level. The findings led to the conclusion that the determination of miRNA-129 and VEGF can significantly contribute to the diagnosis of prostate disorders in dogs.

Contrast-Enhanced Ultrasound Imaging of Prostate Gland in Neutered Dogs

Prostatic neoplasia (PN) occurs in 5-7% of dogs with prostatic disease, with castrated dogs having the same or higher prevalence when compared to intact dogs. Considering the promising results achieved by performing contrast-enhanced ultrasound (CEUS) in intact dogs to detect PN, the present study aimed to acquire data on the prostatic perfusion pattern in neutered dogs. CEUS was performed in 64 neutered dogs, using a 5-7.5 MHz linear transducer with coded harmonic capability, dedicated analytical software, and a second-generation contrast agent, SonoVue. After B-mode evaluation was performed to assess mean prostate volume, the CEUS examination was undertaken. The flow of contrast agent was visible 10 s after injection. The subcapsular vessels were highlighted and produced rapid peripheral rim enhancement. Subsequently, the contrast agent reached the prostatic urethra via the parenchymal arterioles and gradually reached the entire prostate. Perfusion peak intensity (PPI) and time to peak (TTP) values were respectively 45.3% and 34.1 s. The measured parameters were compared with those obtained in previous studies on intact dogs with normal and with pathological patterns. In this study, CEUS showed features that may be promising for its use as a diagnostic tool for early detection of PN in neutered dogs.

PDA Indolylmaleimides Induce Anti-Tumor Effects in Prostate Carcinoma Cell Lines Through Mitotic Death

Castrate resistant prostate cancer in men shares several characteristics with canine prostate cancer (PCa). Due to current insufficient therapies, evaluating novel therapeutic agents for late-stage PCa is of considerable interest for both species. PDA indolylmaleimides showed anticancer effects in several neoplastic cell lines. Herein, a comparative characterization of PDA-66 and PDA-377 mediated effects was performed in human and canine PCa cell lines, which is also the first detailed characterization of these agents on cells derived from solid tumors in general. While PDA-377 showed only weak growth inhibition on human PCa cell lines, PDA-66 inhibited proliferation and induced apoptosis in human and canine cell lines with concentrations in the low micromolar range. Morphological characterization and whole transcriptome sequencing revealed that PDA-66 induces mitotic death through its microtubule-depolymerizing ability. PDA-66 appears to be a worthwhile anti-mitotic agent for further evaluation. The similarities in cellular and molecular response observed in the cell lines of both origins form a solid basis for the use of canine PCa in vivo models to gain valuable interchangeable data to the advantage of both species.

Assisting Decision-Making on Age of Neutering for Mixed Breed Dogs of Five Weight Categories: Associated Joint Disorders and Cancers

The early neutering of male and female dogs and its relationship to an increased risk of joint disorders and some cancers has recently become a concern, raising questions about the standard practice in the U.S. and much of Europe of neutering by 6 months of age. A noteworthy recent finding from this center is that there are major breed differences with small-dog breeds generally showing little vulnerability to neutering compared with breeds of larger body size. These findings on purebreds raise questions for dog owners and veterinarians about mixed-breed dogs. The purpose of this study was to examine a sample of mixed breed dogs of five weight categories using the same veterinary hospital database and diagnostic criteria for joint disorders and cancers as used in the newly published paper on 35 breeds and previous papers on the Golden Retriever, Labrador Retriever, and German Shepherd Dog. The weight categories were <10 kg (739 cases), 10–19 kg (546 cases), 20–29 kg (992 cases), 30–39 kg (604 cases), and over 40 kg (258 cases). Males and females were analyzed separately, as were various ages at neutering. The joint disorders examined were hip dysplasia, cranial cruciate ligament tear or rupture, and elbow dysplasia. The cancers were lymphoma, mast cell tumor, hemangiosarcoma, and osteosarcoma. There was no significant increased occurrence of one or more cancers, compared with intact dogs, in any weight category. However, in the three categories of dogs weighing 20 kg or more, neutering before 1 year generally was significantly associated with risks of one or more joint disorders above that of dogs left intact, commonly to 3 times the level of intact dogs, with sex differences in the degrees of joint disorders associated with neutering. For the dogs in the two weight categories <20 kg, no increased risks were found for joint disorders. This information can be useful to dog caregivers in deciding on the age at which to neuter specific dogs, and for veterinarians offering guidance to pet owners.