Prevalence of autosomal dominant polycystic kidney disease in Persian and Persian-related cats in Brazil.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disease in cats. However, scarce data on its prevalence are available in Brazil. Persian cats and Persian-related breeds were assessed by molecular genotyping for a C to A transversion in exon 29 of PKD1 gene to determine ADPKD prevalence in a Brazilian population. Genomic DNA extracted from peripheral whole blood or oral swabs samples was used to amplify exon 29 of PKD1 gene employing a PCR-RFLP methodology. From a total of 616 animals, 27/537 Persian and 1/17 Himalayan cats showed the single-nucleotide variant (C to A) at position 3284 in exon 29 of feline PKD1. This pathogenic variation has been identified only in heterozygous state. The prevalence of ADPKD in Persian cats and Persian-related breeds was 5.03% and 1.6%, respectively. There was no significant association between feline breed, gender or age with ADPKD prevalence. Of note, the observed ADPKD prevalence in Persian cats and Persian-related breeds in Brazil was lower than the ones reported in other parts of the world. This finding may be related to genetic counseling and consequent selection of ADPKD-free cats for reproduction.

Prevalence of autosomal dominant polycystic kidney disease in Persian and Persian-related cats in Brazil / Prevalência da doença renal policística autossômica dominante em gatos Persas e raças relacionadas no Brasil

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disease in cats. However, scarce data on its prevalence are available in Brazil. Persian cats and Persian-related breeds were assessed by molecular genotyping for a C to A transversion in exon 29 of PKD1 gene to determine ADPKD prevalence in a Brazilian population. Genomic DNA extracted from peripheral whole blood or oral swabs samples was used to amplify exon 29 of PKD1 gene employing a PCR-RFLP methodology. From a total of 616 animals, 27/537 Persian and 1/17 Himalayan cats showed the single-nucleotide variant (C to A) at position 3284 in exon 29 of feline PKD1. This pathogenic variation has been identified only in heterozygous state. The prevalence of ADPKD in Persian cats and Persian-related breeds was 5.03% and 1.6%, respectively. There was no significant association between feline breed, gender or age with ADPKD prevalence. Of note, the observed ADPKD prevalence in Persian cats and Persian-related breeds in Brazil was lower than the ones reported in other parts of the world. This finding may be related to genetic counseling and consequent selection of ADPKD-free cats for reproduction.

A doença renal policística autossômica dominante (DRPAD) é a doença genética mais comum em gatos. No entanto, poucos dados sobre sua prevalência estão disponíveis no Brasil. Gatos Persas e de raças relacionadas foram avaliados por genotipagem molecular para a transversão C→A no exon 29 do gene PKD1 felino para determinar a prevalência de DRPAD. DNA genômico extraído de sangue total periférico ou amostras de swabs orais foram utilizados para amplificar o exon 29 do gene PKD1 pela técnica de PCR-RFLP. De um total de 616 gatos, 27/537 Persas e 1/17 Himalaia mostraram a variante de nucleotídeo único (C→A) na posição 3284 no exon 29 do gene PKD1. Esta variante patogênica foi identificada apenas em heterozigose. A prevalência de DRPAD em gatos Persas e raças relacionadas foram de 5,03% e 1,6%, respectivamente. Não houve associações significativas entre raça, gênero ou idade dos felinos e incidência de DRPAD. A prevalência de DRPAD em gatos Persas e raças relacionadas no Brasil foi menor do que em outras partes do mundo, o que pode estar relacionado ao aconselhamento genético e consequente seleção de gatos sem ADPKD para reprodução.

Ultrasound-guided biopsy of the equine forelimb proximal suspensory ligament by longitudinal access / [Biópsia guiada por ultrassom da origem do ligamento suspensor do boleto de equinos por acesso longitudinal]

A literatura atual discute múltiplas modalidades de imagem para acompanhar o processo de cicatrização da origem do ligamento suspensor do boleto (LSB) em equinos, mas nenhuma pode garantir que eles possuam fibras colágenas com calibre suficiente para suportar o retorno ao exercício. Já as técnicas morfológicas e bioquímicas, bem como a análise de birrefringência, podem ser mais apropriadas para caracterizar o processo de cicatrização e avaliar a eficiência do tratamento. O objetivo deste artigo é descrever procedimento simples que possibilita a coleta de amostras teciduais de boa qualidade e em sentido longitudinal, por biópsia em equinos em estação. Após antissepsia local, sedação e bloqueio do nervo palmar lateral no aspecto medial do osso acessório do carpo (OAC), o membro foi colocado em suspensão com o carpo flexionado em 90º; a agulha de biópsia guiada por ultrassom foi introduzida em sentido distoproximal, 11 a 13cm distal ao OAC, ângulo de 20º em relação ao LSB, até a região de sua origem. O equipamento foi disparado e coletou-se a amostra tecidual. Essa técnica possibilitou a coleta de fragmentos de boa qualidade para análise histológica e de birrefringência, sem reações adversas, podendo ser usada em modelos experimentais ou na prática clínica.(AU)

Uterine cervix as a fundamental part of the pathogenesis of pregnancy loss associated with ascending placentitis in mares.

Anatomical and molecular changes in the cervical barrier in women are a fundamental part of the pathogenesis of pregnancy loss associated with chorioamnionitis. However, there is little information regarding changes in the cervix associated with ascending infection in pregnant mares. To better characterize morphological and molecular changes in the cervix during placentitis, we examined full thickness histology and mRNA expression for a number of inflammatory and endocrine factors in the mucosa and stroma of the cervix of mares (n = 5) after experimental induction of placentitis via transcervical inoculation with Streptococcus equi ssp zooepidemicus at approximately 290d of gestation. Gestationally age-matched mares (n = 4) served as controls. Target transcripts included steroid receptors (PGR, ESR1 and 2), OXTR, prostaglandins synthases and receptors (PTGS1, PTGS2, PGES, PGFS, PTGER2 and PTGER4), cytokines (IL1b, IL6, CLCX8, IL10 and TNFα) and acute phase proteins (SAA). Histologically, a marked modification in the cervical epithelia and stroma was characterizing cervicitis. Additionally, the mRNA expression of IL1ß, IL6, CXCL8, SAA and PTGS2 was greater (P < 0.05) in both mucosa and stroma of the inoculated mares; whereas TNFα, IL10 and PGES were upregulated (P < 0.05) only in the cervical mucosa. Progesterone receptor, ESR1 and PTGER4 were upregulated in the cervical stroma of placentitis mares. In conclusion, the cervical response to placentitis was characterized by an upregulation of inflammatory cytokines that was accompanied by induction of PTGS2 and PGES. Further, receptors known to be associated with relaxation of the cervix in other species (ESR1 and PTGER4) were upregulated in the cervical stroma of placentitis mares. These findings indicate that the cervix is not only a physical barrier but that it has an active role in the pathogenesis of ascending placentitis.

Green Tea Prevents NAFLD by Modulation of miR-34a and miR-194 Expression in a High-Fat Diet Mouse Model.

BACKGROUND/AIMS: Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome. It is currently the most common chronic liver disease with complex pathogenesis and challenging treatment. Here, we investigated the hepatoprotective role of green tea (GT) and determined the involvement of miRNAs and its mechanism of action. METHODS: Male C57Bl/6 mice were fed with a high-fat diet for 4 weeks. After this period, the animals received gavage with GT (500 mg/kg body weight) over 12 weeks (5 days/week). HepG2 cell lines were transfected with miR-34a or miR-194 mimetics and inhibitors to validate the in vivo results or were treated with TNF-α to evaluate miRNA regulation. RESULTS: GT supplementation protects against NAFLD development by altering lipid metabolism, increasing gene expression involved in triglycerides and fatty acid catabolism, and decreasing uptake and lipid accumulation. This phenotype was accompanied by miR-34a downregulation and an increase in their mRNA targets Sirt1, Pparα, and Insig2. GT upregulated hepatic miR-194 by inhibiting TNF-α action leading to a decrease in miR-194 target genes Hmgcs/Apoa5. CONCLUSION: Our study identified for the first time that the beneficial effects of GT in the liver can be due to the modulation of miRNAs, opening new perspectives for the treatment of NAFLD focusing on epigenetic regulation of miR-34a and miR-194 as green tea targets.

Evaluation of Cytopathological Techniques for the Diagnosis of Canine Visceral Leishmaniosis with Lymph Node Samples.

The identification of the parasite in cytological smears of lymph node aspirates is a widely applied technique for the direct diagnosis of Leishmania spp. infection, especially in endemic areas. Although very specific, this method has limited sensitivity, and improving the technique would be highly desirable. This study aimed to evaluate the efficacy of conventional smear cytology (SC), liquid-based cytology (LBC), cell block (CB) stained with haematoxylin and eosin (HE) and immunocytochemistry (ICC), and formalin-fixed paraffin wax-embedded tissue immunohistochemistry (FFPE-IHC) compared with serology and polymerase chain reaction for the diagnosis of canine visceral leishmaniosis (CVL) in lymphoid tissue. The use of a preservative medium and centrifugation for cytological samples reduced the number of unsatisfactory artefacts/background. Moreover, LBC allowed excellent cellular preservation and the application of ancillary techniques, such as CB and ICC. SC was the most accurate morphological diagnostic method (45.0%). CB-ICC alone or associated with SC demonstrated significantly higher sensitivity (70.0% and 72.0%, respectively) when compared with SC alone (34.00%). CB-ICC was found to be more effective in the detection of infected animals with mild clinical signs, similar to FFPE-IHC. The specificity and positive predictive value were similar between all methods. Finally, the detection limit for CB-ICC and SC + CB-ICC was identical (18.46 amastigotes/mm2). Our study suggests that CB-ICC is a promising tool for improvement of the cytopathological diagnosis of CVL and may be applied in routine epidemiological screening.

Prevalence of autosomal dominant polycystic kidney disease in Persian and Persian-related cats in Brazil

Abstract Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disease in cats. However, scarce data on its prevalence are available in Brazil. Persian cats and Persian-related breeds were assessed by molecular genotyping for a C to A transversion in exon 29 of PKD1 gene to determine ADPKD prevalence in a Brazilian population. Genomic DNA extracted from peripheral whole blood or oral swabs samples was used to amplify exon 29 of PKD1 gene employing a PCR-RFLP methodology. From a total of 616 animals, 27/537 Persian and 1/17 Himalayan cats showed the single-nucleotide variant (C to A) at position 3284 in exon 29 of feline PKD1. This pathogenic variation has been identified only in heterozygous state. The prevalence of ADPKD in Persian cats and Persian-related breeds was 5.03% and 1.6%, respectively. There was no significant association between feline breed, gender or age with ADPKD prevalence. Of note, the observed ADPKD prevalence in Persian cats and Persian-related breeds in Brazil was lower than the ones reported in other parts of the world. This finding may be related to genetic counseling and consequent selection of ADPKD-free cats for reproduction.

Resumo A doença renal policística autossômica dominante (DRPAD) é a doença genética mais comum em gatos. No entanto, poucos dados sobre sua prevalência estão disponíveis no Brasil. Gatos Persas e de raças relacionadas foram avaliados por genotipagem molecular para a transversão CA no exon 29 do gene PKD1 felino para determinar a prevalência de DRPAD. DNA genômico extraído de sangue total periférico ou amostras de swabs orais foram utilizados para amplificar o exon 29 do gene PKD1 pela técnica de PCR-RFLP. De um total de 616 gatos, 27/537 Persas e 1/17 Himalaia mostraram a variante de nucleotídeo único (CA) na posição 3284 no exon 29 do gene PKD1. Esta variante patogênica foi identificada apenas em heterozigose. A prevalência de DRPAD em gatos Persas e raças relacionadas foram de 5,03% e 1,6%, respectivamente. Não houve associações significativas entre raça, gênero ou idade dos felinos e incidência de DRPAD. A prevalência de DRPAD em gatos Persas e raças relacionadas no Brasil foi menor do que em outras partes do mundo, o que pode estar relacionado ao aconselhamento genético e consequente seleção de gatos sem ADPKD para reprodução.

Effect of long-term ingestion of weakly oxidised flaxseed oil on biomarkers of oxidative stress in LDL-receptor knockout mice.

The effect of oxidised fatty acids on atherosclerosis progression is controversial. Thus, our objective was to evaluate the effect of long-term consumption of weakly oxidised PUFA from flaxseed oil on oxidative stress biomarkers of LDL-receptor(-/-) mice. To test our hypothesis, mice were separated into three groups. The first group received a high-fat diet containing fresh flaxseed oil (CONT-), the second was fed the same diet prepared using heated flaxseed oil (OXID), and the third group received the same diet containing fresh flaxseed oil and had diabetes induced by streptozotocin (CONT+). Oxidative stress, aortic parameters and non-alcoholic fatty liver disease were assessed. After 3 months, plasma lipid profile, glucose levels, body weight, energy intake and dietary intake did not differ among groups. Likewise, oxidative stress, plasma malondialdehyde (MDA), hepatic MDA expressed as nmol/mg portion (ptn) and antioxidant enzymes did not differ among the groups. Hepatic linoleic acid, α-linolenic acid, arachidonic acid and EPA acid declined in the OXID and CONT+ groups. Aortic wall thickness, lumen and diameter increased only in the OXID group. OXID and CONT+ groups exhibited higher concentrations of MDA, expressed as µmol/mg ptn per %PUFA, when compared with the CONT- group. Our results suggest that ingestion of oxidised flaxseed oil increases hepatic MDA concentration and is potentially pro-atherogenic. In addition, the mean MDA value observed in all groups was similar to those reported in other studies that used xenobiotics as oxidative stress inducers. Thus, the diet applied in this study represents an interesting model for further research involving antioxidants.

Sorafenib prevents liver fibrosis in a non-alcoholic steatohepatitis (NASH) rodent model

Liver fibrosis occurring as an outcome of non-alcoholic steatohepatitis (NASH) can precede the development of cirrhosis. We investigated the effects of sorafenib in preventing liver fibrosis in a rodent model of NASH. Adult Sprague-Dawley rats were fed a choline-deficient high-fat diet and exposed to diethylnitrosamine for 6 weeks. The NASH group (n=10) received vehicle and the sorafenib group (n=10) received 2.5 mg·kg-1·day-1 by gavage. A control group (n=4) received only standard diet and vehicle. Following treatment, animals were sacrificed and liver tissue was collected for histologic examination, mRNA isolation, and analysis of mitochondrial function. Genes related to fibrosis (MMP9, TIMP1, TIMP2), oxidative stress (HSP60, HSP90, GST), and mitochondrial biogenesis (PGC1α) were evaluated by real-time quantitative polymerase chain reaction (RT-qPCR). Liver mitochondrial oxidation activity was measured by a polarographic method, and cytokines by enzyme-linked immunosorbent assay (ELISA). Sorafenib treatment restored mitochondrial function and reduced collagen deposition by nearly 63% compared to the NASH group. Sorafenib upregulated PGC1α and MMP9 and reduced TIMP1 and TIMP2 mRNA and IL-6 and IL-10 protein expression. There were no differences in HSP60, HSP90 and GST expression. Sorafenib modulated PGC1α expression, improved mitochondrial respiration and prevented collagen deposition. It may, therefore, be useful in the treatment of liver fibrosis in NASH.

Sorafenib prevents liver fibrosis in a non-alcoholic steatohepatitis (NASH) rodent model.

Liver fibrosis occurring as an outcome of non-alcoholic steatohepatitis (NASH) can precede the development of cirrhosis. We investigated the effects of sorafenib in preventing liver fibrosis in a rodent model of NASH. Adult Sprague-Dawley rats were fed a choline-deficient high-fat diet and exposed to diethylnitrosamine for 6 weeks. The NASH group (n=10) received vehicle and the sorafenib group (n=10) received 2.5 mg·kg(-1)·day(-1) by gavage. A control group (n=4) received only standard diet and vehicle. Following treatment, animals were sacrificed and liver tissue was collected for histologic examination, mRNA isolation, and analysis of mitochondrial function. Genes related to fibrosis (MMP9, TIMP1, TIMP2), oxidative stress (HSP60, HSP90, GST), and mitochondrial biogenesis (PGC1α) were evaluated by real-time quantitative polymerase chain reaction (RT-qPCR). Liver mitochondrial oxidation activity was measured by a polarographic method, and cytokines by enzyme-linked immunosorbent assay (ELISA). Sorafenib treatment restored mitochondrial function and reduced collagen deposition by nearly 63% compared to the NASH group. Sorafenib upregulated PGC1α and MMP9 and reduced TIMP1 and TIMP2 mRNA and IL-6 and IL-10 protein expression. There were no differences in HSP60, HSP90 and GST expression. Sorafenib modulated PGC1α expression, improved mitochondrial respiration and prevented collagen deposition. It may, therefore, be useful in the treatment of liver fibrosis in NASH.

The value of molecular expression of KIT and KIT ligand analysed using real-time polymerase chain reaction and immunohistochemistry as a prognostic indicator for canine cutaneous mast cell tumours.

This study investigated the correlation between KIT gene expression determined by immunohistochemistry and real-time polymerase chain reaction (RT-PCR) and the rate of tumour recurrence and tumour-related deaths in dogs affected with mast cell tumour (MCT). Kaplan-Meier curves were constructed to compare tumour recurrence and tumour-related death between patients. The log-rank test was used to check for significant differences between curves. KIT-I, KIT-II and KIT-III staining patterns were observed in 9 (11.11%), 50 (61.73%) and 22 (27.16%) tumours, respectively. Tumour recurrence rates and tumour-related deaths were not associated with KIT staining patterns (P = 0278, P > 0.05), KIT (P = 0.289, P > 0.05) or KIT ligand (P = 0.106, P > 0.05) gene expression. Despite the lack of association between KIT staining pattern and patient survival time, the results suggest a correlation between aberrant KIT localization and increased proliferative activity of MCTs. RT-PCR seems to be a sensible method for quantitative detection of KIT gene expression in canine MCT, although expressions levels are not correlated with prognosis.

Cirrhosis in rats does not resolve in the long-term after induction by thioacetamide model

Introductions: Hepatic cirrhosis is a final common pathway of all chronic liver diseases, characterized by deposit of fibrillar collagen and liver failure. Materials and Methods: In this experiment, hepatic cirrhosis was induced in 15 female Wistar rats by a 14-week period, with thioacetamide solution in a 200 mg/kg dosage, via intraperitoneal. Animals were submitted to liver biopsy, and euthanized after a 80-day post-induction period. Serum biochemical analysis was performed, in addition to histopathology by H.E., Picrosirius, Alcian Blue and P.A.S. stainings, following analysis of histological activity index and staging of fibrosis. Morphometric analysis of collagen on Picrosirius slides was also performed. Results: Mortality during experimental period was low (13.33%), and after 80-day period, liver function improved, cellular changes did not altered, and deposition of acidic mucopolysaccharides and glycogen were increased. Liver histological activity did not change significantly (7.25 ± 1.30 to 6.41 ± 1.32), but staging of fibrosis was altered (3.91 ± 0.76 to 4.70 ± 1.11). Interlobular collagen showed a significant decrease (5.14 ± 2.00 to 4.00 ± 1.20), while intralobular collagen was increased (0.23 ± 0.06 to 0.36 ± 0.08). Conclusions: These findings characterize thioacetamide as a safe experimental model for induction cirrhosis, which may be used for future therapy studies.(AU)

S-Nitroso-N-acetylcysteine induces de-differentiation of activated hepatic stellate cells and promotes antifibrotic effects in vitro.

Nitric oxide (NO) has been shown to act as a potent antifibrogenic agent by decreasing myofibroblast differentiation. S-Nitroso-N-acetylcysteine (SNAC), a NO donor, attenuates liver fibrosis in rats, but the cellular and molecular mechanisms on liver myofibroblast-like phenotype still remain unknown. Here, we investigate the antifibrotic effects of SNAC on hepatic stellate cells, the major fibrogenic cell type in the liver. A murine GRX cell line was incubated with SNAC (100µM) or vehicle (control group) for 72h. Cell viability was measured by MTT colorimetric assay and the conversion of myofibroblast into quiescent fat-storing cell phenotype was evaluated by Oil-Red-O staining. TGFß-1, TIMP-1, and MMP-13 levels were measure in the supernatant by ELISA. Profibrogenic- and fibrolytic-related gene expression was quantified using real-time qPCR. SNAC induced phenotype conversion of myofibroblast-like phenotype into quiescent cells. SNAC decreased gene and protein expression of TGFß-1 and MMP-2 compared to control groups. Besides, SNAC down-regulated profibrogenic molecules and up-regulated MMP-13 gene expression, which plays a key role in the degradation of interstitial collagen in liver fibrosis. In conclusion, these findings demonstrate that SNAC efficiently can modulate the activation and functionality of murine hepatic stellate cells and could be considered as an antifibrotic treatment to human liver fibrosis.

Modelo de suplementação nutricional com fatores hepatotróficos aumenta proliferação celular em fígado de ratos sadios / Model of nutritional supplementation with hepatotrophic factors increases cell proliferation in the liver of healthy rats

Foram avaliados dois protocolos de administração, em ratos sadios, de uma solução de fatores hepatotróficos (FH), composta por aminoácidos, vitaminas, sais minerais, glicose, insulina, glucagon e triiodotironina (T3). A solução foi administrada durante 10 dias, 40mg/kg/dia, i.p., em duas, grupo 2xFH (n=15), ou três doses, grupo 3xFH (n=15), diárias. Foram observados os efeitos na proliferação celular dos hepatócitos, na angiogênese e na matriz extracelular hepática, assim como as possíveis reações adversas. Os animais dos grupos 2xFH e 3xFH apresentaram aumento da massa hepática de 30,1 por cento e 22,5 por cento, respectivamente, em relação ao grupo-controle (CT; n=15). O índice de proliferação hepatocelular foi maior nos grupos 2xFH (1,4 por cento) e 3xFH (1,2 por cento) em relação ao grupo CT (0,53 por cento), e a densitometria relativa do fator de crescimento do endotélio vascular pelo imunoblot não revelou diferença estatística entre os três grupos. Nos grupos 2xFH e 3xFH, houve redução do colágeno intersticial em relação ao grupo CT. A solução de FH estimulou o crescimento hepático e reduziu o volume de colágeno perissinusoidal. A administração em três doses diárias resultou em mortalidade de 26,7 por cento, possivelmente pelo excessivo estresse da manipulação e pela menor adaptação fisiológica dos ratos, o que não ocorreu nos grupos 2xFH e CT. Para esse tipo de abordagem em ratos, o procedimento experimental mais apropriado, seguro, com melhor chance de adaptação dos animais e com resultados significativos é a aplicação dos FH em duas doses diárias.

Two protocols of hepatotrophic factors (HF) administration, in solution composed by aminoacids, vitamins, mineral salts, glucose, insulin, glucagon, and triiodothyronine were evaluated in healthy rats. This solution was administered for 10 days, (40mg/kg/day) i.p., in two (group 2xFH; n=15) or three daily doses (group 3xFH n=15). The effects on hepatocytes cell proliferation, angiogenesis, and hepatic extracellular matrix, and also possible adverse reactions were analyzed. Animals of groups 2xFH and 3xFH presented an increase in hepatic mass of 30.1 percent and 22.5 percent, respectively, when compared rats of control group (CT; n=15). Hepatocellular proliferation index was higher in rats of groups 2xFH (1.4 percent) and 3xFH (1.2 percent) when compared to CT group animals (0.53 percent), and the relative densitometry of the vascular endothelial growth factor analyzed with immunoblot did not show a significant difference among the three groups. Rats of groups 2xFH and 3xFH showed a reduction of interstitial collagen when compared to CT rats. HF solution stimulated hepatic growth and reduced the volume of perisinusoidal collagen. Administration in three daily doses resulted in 26.7 percent mortality, possibly due to excessive stress from manipulation and lower physiological adaptation of rats, which did not occur in rats of groups 2xFH and CT. The more appropriate and safer experimental procedure for this approach in rats with higher chance of animal adaptation and significant results is the application of HF in two daily doses.

Identification of hepatic stem/progenitor cells in canine hepatocellular and cholangiocellular carcinoma.

Hepatic progenitor cells (HPCs) are bipotential stem cells residing in human and animal livers that are able to differentiate towards the hepatocytic or cholangiocytic lineages. HPCs are present in both hepatocellular (HCC) and cholangiocellular carcinoma (CC) in humans; and a small percentage of HCC can originate from cancer stem cells. However, its distribution in canine liver tumour has not been studied. Herein, we searched for stem/progenitor cells in 13 HCC and 7 CC archived samples by immunohistochemical analysis. We found that both liver tumours presented a higher amount of K19-positive HPCs. Besides, 61.6% of HCC cases presented immature CD44-positive hepatocytes. Nevertheless, only two cases presented CD133-positive cells. As observed in humans, hepatic canine tumours presented activated HPCs, with important differentiation onto hepatocytes-like cells and minimal role of cancer stem cells on HCC. These findings reiterate the applicability of canine model in the search for new therapies before application in humans.

Immunohistochemical characterization of canine prostatic intraepithelial neoplasia.

The development of prostate cancer is believed to be a multistep process, progressing sequentially from normal epithelium, to prostatic intraepithelial neoplasia (PIN) and, finally, to invasive neoplasia. Malignant stem cells within the basal cell layer of the prostatic epithelium are believed to play an important role in the failure of androgen-ablation therapy that occurs in the most advanced form of prostate cancer. The aim of the present study was to immunohistochemically characterize the lesions of canine PIN. Prostatic tissue from five dogs with PIN was compared with normal prostate tissue from nine further dogs. There was an increase in the number of basal epithelial cells in lesions consistent with PIN as defined by expression of the nuclear protein p63. These lesions had elevated expression of proliferating cell nuclear antigen (PCNA) and heterogeneous labelling for the nuclear androgen receptor (AR). These findings suggest that the basal cells present in PIN may play a role in canine prostate carcinogenesis and that the proliferation of these cells occurs despite the heterogeneous expression of the AR.

Expression of connexins in normal and neoplastic canine bone tissue.

Previous studies showed that intercellular communication by gap junctions has a role in bone formation. The main connexin involved in the development, differentiation, and regulation of bone tissue is connexin (Cx) 43. In addition, Cx46 is also expressed, mostly localized within the trans-Golgi region. Alterations in the expression pattern and aberrant location of these connexins are associated with oncogenesis, demonstrating a deficient gap junctional intercellular communication (GJIC) capacity in neoplastic tissues. In this study, we evaluated normal and neoplastic bone tissues regarding the expression of Cx43 and Cx46 by immunofluorescence, gene expression of these connexins by real-time PCR, and their correlation with cell proliferation index and deposition of collagen. Fourteen neoplastic bone lesions, including 13 osteosarcomas and 1 multilobular tumor of bone, were studied. The mRNA levels of Cx43 were similar between normal and neoplastic bone tissue. In normal bone tissue, the Cx43 protein was found mainly in the intercellular membranes. However, in all bone tumors studied here, the Cx43 was present in both cell membranes and also aberrantly in the cytoplasm. Regarding only tumor samples, we determined a possible inverse correlation between Cx43 expression and cellular proliferation, although a positive correlation between Cx43 expression and collagen deposition was also noted. In contrast, Cx46 had lower levels of expression in neoplastic bone tissues when compared with normal bone and was found retained in the perinuclear region. Even though there are differences between these two connexins regarding expression in neoplastic versus normal tissues, we concluded that there are differences regarding the subcellular location of these connexins in normal and neoplastic dog bone tissues and suggest a possible correlation between these findings and some aspects of cellular proliferation and possibly differentiation.