Is there a rationale to supplement hepatotropic factors to dogs with multiple acquired portosystemic shunts secondary to congenital portosystemic shunt attenuation?

Experimental rat models and clinical trials in human patients with liver cirrhosis show evidence that supplementation with hepatotropic factors provides therapeutic benefits. This form of support has not yet been described in dogs with multiple acquired portosystemic shunts (MAPSS) despite similarities between both pathological conditions. Especially hepatocyte growth factor (HGF) and branched chain amino acids (BCAA) deserve closer attention. High-quality vegetable rather than animal proteins have been suggested to form an excellent dietary source of BCAA, and leucine seems the best candidate for supplementation given its stimulating effects on liver function in general and on HGF secretion specifically. Research on optimal ways of administration of HGF in dogs with MAPSS secondary to congenital portosystemic shunt attenuation is necessary before clinical trials can be initiated.

Evaluation of the agreement between Brix refractometry and serum immunoglobulin concentration in neonatal piglets

Neonatal piglets lack immunoglobulins at birth. Sufficient colostrum intake (CI) and immunoglobulin absorption are essential for an appropriate passive transfer of immunity via the colostrum. Most methods to measure immunoglobulins in serum of piglets are labour-intensive, expensive or imprecise and not designed for on-farm use. The present diagnostic test study evaluated digital Brix refractometry to measure immunoglobulins in serum of neonatal piglets and to suggest thresholds for different serum immunoglobulin concentration. Additionally, agreements between Brix refractometry and optical refractometer (serum total protein, STP) and between Brix refractometry and ELISA (immunoglobulin G, IgG) were also investigated. Forty-five sows and 269 piglets from three different farms were enrolled in the study. Piglets were weighed at birth and 24 h later to calculate the CI. Serum was collected at 24 h after birth and analysed for STP, γ-globulins (electrophoresis), % Brix and IgG. In piglets, median (interquartile range, IQR) CI was 412 (196) g per piglet. Median (IQR) STP, γ-globulin and % Brix concentrations in piglet serum were 60 (11) g/L, 35 (10) g/L and 8 (2) %, respectively. Average (±SD) IgG concentration was 49 ± 23 g/L. Passing-Bablok regression revealed a strong concordance between % Brix and STP (Kendall's tau (Τ): 0.620, P < 0.0001, n = 267) and % Brix and γ-globulin concentration (Kendall's Τ: 0.575, P < 0.0001, n = 267). The agreement between the Brix refractometer and IgG concentration was poor (Kendall's Τ: 0.267, P < 0.0001, n = 269). Receiver operating characteristic curves were performed to evaluate test characteristics of Brix refractometry for three γ-globulin cut-off values, i.e. 10, 20 and 30 g/L. The % Brix cut-off values resulting in the optimal combination of sensitivity and specificity were 5.4 (100 and 98.5%), 7.0 (100 and 89.3%) and 7.9 (90.1 and 80.6%), respectively. In conclusion, digital Brix refractometry is a sufficiently fast and practical method to assess serum γ-globulin concentrations in neonatal piglets on-farm and to evaluate them by considering the thresholds found in this study. Further studies are needed to validate those thresholds regarding piglet's survival in the pre-weaning period.

Vraag & Antwoord

1. Keelsnede bij noodslachting van runderen 2. Kan castratie een hond rustiger maken?

Treatment of a malignant peripheral nerve sheath tumor by intravenous administration of combretastatin A4-phosphate in a dog

A fifteen-year-old, male, castrated American Staffordshire terrier was presented with a subcutaneous, ulcerated mass on the right carpal joint. Thoracic radiographs and abdominal ultrasound were both negative for metastatic disease. Punch biopsies revealed the histopathological diagnosis of a malignant peripheral nerve sheath tumor. Due to the extent of the primary mass, local excision was not possible, and amputation of the limb was not an option for the owner. The dog was treated with intravenous administration of combretastatin A4-phosphate, a vascular disrupting agent. A biopsy was taken before and after treatment and power-Doppler ultrasound and contrast-enhanced ultrasound were performed to assess pre- and posttreatment evaluation of the tumor vasculature. The treatment resulted in massive necrosis of the tumor.

A single dose of intravenous combretastatin A4-phosphate is reasonably well tolerated and significantly reduces tumour vascularization in canine spontaneous cancers

Combretastatin A4-phosphate (CA4P) is an anti-tumour vascular targeting agent which selectively blocks tumour blood flow. Research on CA4P in rodent tumour models is extensive; however, knowledge of its effect on spontaneous cancer is scarce. This study was conducted in canine patients with spontaneous solid tumours. The goal was to assess the toxicity and efficacy of CA4P in various spontaneous tumour types. Eight dogs with spontaneous tumours were enrolled and treated with a single dose of 75 mg m^-2 intravenous CA4P. The dogs were screened and monitored before and after injection. Pre- and post-treatment tumour blood flow was analysed in vivo by power Doppler ultrasound (PDUS) and contrast-enhanced ultrasound (CEUS). Vessel destruction and tumour necrosis were evaluated by histopathology. Clinically relevant toxicity was limited to one case of temporary tetraparesis; other adverse events were mild. Significant cardiovascular changes were mostly confined to changes in heart rate and cTnI levels. Macroscopic tumour size reduction was evident in 2 dogs. Based on PDUS and CEUS, CA4P induced a significant decrease in vascular index and tumour blood flow. Post-treatment, histopathology revealed a significant increase of necrotic tumoural tissue and a significant reduction in microvessel density in tumoural tissue. Anti-vascular and necrotizing effects of CA4P were documented in a variety of canine spontaneous cancers with only minimal side effects. This is the first study reporting the administration of CA4P to canine cancer patients with in vivo and ex vivo assessment, and a first step toward implementing CA4P in combination therapies in veterinary oncology patients. The use of CA4P in canine patients was approved and registered by the Belgian Federal Agency for Medicines and Health Products (FAMHP) (approval number 0002588, registration number 6518 ID 2F12).

Laser capture microdissection of intestinal tissue from sea bass larvae using an optimized RNA integrity assay and validated reference genes

The increasing demand for a sustainable larviculture has promoted research regarding environmental parameters, diseases and nutrition, intersecting at the mucosal surface of the gastrointestinal tract of fish larvae. The combination of laser capture microdissection (LCM) and gene expression experiments allows cell specific expression profiling. This study aimed at optimizing an LCM protocol for intestinal tissue of sea bass larvae. Furthermore, a 3′/5′ integrity assay was developed for LCM samples of fish tissue, comprising low RNA concentrations. Furthermore, reliable reference genes for performing qPCR in larval sea bass gene expression studies were identified, as data normalization is critical in gene expression experiments using RT-qPCR. We demonstrate that a careful optimization of the LCM procedure allows recovery of high quality mRNA from defined cell populations in complex intestinal tissues. According to the geNorm and Normfinder algorithms, ef1a, rpl13a, rps18 and faua were the most stable genes to be implemented as reference genes for an appropriate normalization of intestinal tissue from sea bass across a range of experimental settings. The methodology developed here, offers a rapid and valuable approach to characterize cells/tissues in the intestinal tissue of fish larvae and their changes following pathogen exposure, nutritional/environmental changes, probiotic supplementation or a combination thereof.

Angiogenesis and collagen type IV expression in different endothelial cell culture systems

In vitro angiogenesis assays constitute an important tool for studying the mechanisms of angiogenesis and for identification of pro- and anti-angiogenic substances. Therefore, endothelial cell and media systems used for in vitro angiogenesis assays are required to mimic the angiogenic process in vivo including endothelial capability to express collagen type IV as a component of the basement membrane. In this study, the expression of collagen type IV and its α chains (α1-6) was investigated in different endothelial cell culture systems in vitro qualitatively and quantitatively. These systems included four different batches of microvascular endothelial cells derived from the human skin, heart and lung, from which only two batches were found to be angiogenic and two batches were classified as non-angiogenic. Distribution of the transcripts of the α chains of collagen type IV was similar in all cell and media systems investigated. However, secretion and deposition of a stable extracellular network of collagen type IV could only be observed in the angiogenic cultures. In conclusion, the consecutive steps of the angiogenic cascade in vivo as well as in vitro depend on an increasing secretion and subsequent extracellular deposition of collagen type IV.

Distribution of the Shadoo protein in the ovine brain assessed by immunohistochemistry

Shadow of prion protein is a gene potentially involved in the pathogenesis of prion diseases. However, the Shadoo protein encoded by this gene has not yet been studied in sheep, an important species in prion matters. Therefore, we developed a polyclonal antibody against ovine Shadoo and assessed the presence and distribution of this protein in the ovine brain by immunohistochemistry. The strongest staining level was found in the cerebellum (especially in the Purkinje cells) and in the pons, but cerebrum, hippocampus, pituitary gland, medulla oblongata, thalamus and hypothalamus were also immunopositive. Remarkably, a typical granular pattern was seen in most of the tested brain tissues, which might indicate that Shadoo is primarily expressed at synapses. The results of this study and the availability of an ovine anti-Shadoo antibody can contribute to future research on the function of Shadoo and on its potential involvement in prion diseases.