Dysbiosis in a canine model of human fistulizing Crohn's disease.

Crohn's disease (CD) is a chronic immune-mediated inflammatory condition caused by the loss of mucosal tolerance toward the commensal microbiota. On average, 29.5% and 42.7% CD patients experience perianal complications at 10 and 20 y after diagnosis, respectively. Perianal CD (pCD) result in high disease burden, diminished quality of life, and elevated health-care costs. Overall pCD are predictors of poor long-term outcomes. Animal models of gut inflammation have failed to fully recapitulate the human manifestations of fistulizing CD. Here, we evaluated dogs with spontaneous canine anal furunculosis (CAF), a disease with clinical similarities to pCD, as a surrogate model for understanding the microbial contribution of human pCD pathophysiology. By comparing the gut microbiomes between dogs suffering from CAF (CAF dogs) and healthy dogs, we show CAF-dog microbiomes are either very dissimilar (dysbiotic) or similar (healthy-like), yet unique, to healthy dog's microbiomes. Compared to healthy or healthy-like CAF microbiomes, dysbiotic CAF microbiomes showed an increased abundance of Bacteroides vulgatus and Escherichia coli and a decreased abundance of Megamonas species and Prevotella copri. Our results mirror what have been reported in previous microbiome studies of patients with CD; particularly, CAF dogs exhibited two distinct microbiome composition: dysbiotic and healthy-like, with determinant bacterial taxa such as E. coli and P. copri that overlap what it has been found on their human counterpart. Thus, our results support the use of CAF dogs as a surrogate model to advance our understanding of microbial dynamics in pCD.

Extracellular Vesicles from Wharton's Jelly Mesenchymal Stem Cells Suppress CD4 Expressing T Cells Through Transforming Growth Factor Beta and Adenosine Signaling in a Canine Model.

Mesenchymal stem cells (MSCs) are widely investigated as potential therapeutic agents due to their potent immunomodulatory capacity. Although specific mechanisms by which MSC acts on immune cells are emerging, many questions remain, including the potential of extracellular vesicles (EVs) to mediate biological activities. Canine MSCs are of interest for both veterinary and comparative models of disease and have been shown to suppress CD4pos T cell proliferation. The aim of this study was to determine whether EV isolated from canine Wharton's jelly-derived MSC (WJ-MSC EV) suppresses CD4pos T cell proliferation using biochemical mechanisms previously ascribed to soluble mediators [transforming growth factor beta (TGF-ß) and adenosine]. WJ-MSC EV exhibited mode of 125 nm diameter, low buoyant density (1.1 g/mL), and expression of EV proteins Alix and TSG101. Functionally, EVs inhibited CD4pos T cell proliferation in a dose-dependent manner, which was absent in EV-depleted samples and EVs from non-MSC fibroblasts. EV suppression of CD4pos T cell proliferation was inhibited by a TGF-ßRI antagonist, neutralizing antibodies to TGF-ß, or A2A adenosine receptor blockade. TGF-ß was present on EVs as latent complexes most likely tethered to EV membrane by betaglycan. These data demonstrate that canine WJ-MSC EV utilizes TGF-ß and adenosine signaling to suppress proliferation of CD4pos T cell and will enable further investigation into mechanisms of immune cell modulation, as well as refinement of WJ-MSC and their EVs for therapeutic application.

Safety of ultrasound-guided fine-needle aspiration of the feline pancreas: a case-control study.

The safety of fine-needle aspiration (FNA) of the feline pancreas has not been reported. The incidence of complications following ultrasound-guided pancreatic FNA in 73 cats (pancreatic aspirate [PA] cats) with clinical and ultrasonographic evidence of pancreatic disease was compared with complications in two groups of matched control cats also diagnosed with pancreatic disease that either had abdominal organs other than the pancreas aspirated (control FNA, n = 63) or no aspirates performed (control no FNA, n = 61). The complication rate within 48 h of the ultrasound and/or aspirate procedure did not differ among the PA cats (11%), control FNA (14%) or control no FNA (8%) cats. There was no difference in rate of survival to discharge (82%, 84% and 83%, respectively) or length of hospital stay among groups. The cytologic recovery rate for the pancreatic samples was 67%. Correlation with histopathology, available in seven cases, was 86%. Pancreatic FNA in cats is a safe procedure requiring further investigation to establish diagnostic value.

Cold agglutinin activity in 2 dogs.

A 5-year-old neutered male Mastiff and an 8-year-old spayed female Labrador Retriever were presented to the University of Minnesota Veterinary Medical Center. The Mastiff was presented for evaluation of lameness and pyoderma one month prior in Missouri, where he tested positive for Ehrlichia canis by serum ELISA test, treated with doxycycline. PCR for Ehrlichia sp, Anaplasma sp, Babesia sp, and Bartonella sp, and PCR for antigen receptor rearrangement were negative, serum protein electrophoresis (SPE) revealed polyclonal gammopathy, and mildly reactive lymphoid cells were seen cytologically. The Labrador presented with a proliferative rostral mandibular gingival mass and lipomas for further presurgical evaluation of cold agglutinin activity documented by a commercial laboratory 2 years earlier prior to removal of a grade II mast cell tumor. This dog had a negative SNAP4Dx, normal SPE, and persistently increased serum ALP activity and polyuria/polydipsia suggestive for hyperadrenocorticism. Both dogs had markedly agglutinated RBC in the EDTA samples that dispersed with warming, and normal plasma color. Cold agglutinin activity was demonstrated by direct saline agglutination testing using whole blood and washed erythrocytes demonstrating agglutination at 30°C, 25°C, 15°C, and 4°C, but not at 37°C. CBC results (ADVIA 2120i) from the Mastiff revealed no significant differences in the RBC results obtained at room temperature (RT) and at 37°C; however, the RT run demonstrated negative bias in neutrophil and platelet concentrations attributed to rapid RBC settling. This uncommon hematologic condition may cause artifacts on the automated leukogram and platelet count, and may be subclinical for long periods.

Neurochemical analysis of rat strain differences in the startle gating-disruptive effects of dopamine agonists.

The disruption of prepulse inhibition (PPI) in rats by dopamine (DA) agonists is used to study the neural basis of strain differences in dopaminergic function. We reported that, compared to Long-Evans (LEH) rats, Sprague-Dawley (SDH) rats are more sensitive to the PPI-disruptive effects of the direct D1/D2 agonist apomorphine (APO) and the indirect DA agonist d-amphetamine (AMPH). This strain difference is heritable, with PPI drug sensitivity following a generational pattern (SDH>N2>F1>LEH) suggestive of additive effects of multiple genes. Here, we assessed the neurochemical bases for these heritable strain differences by measuring tissue levels of dopamine, serotonin (5HT) and their respective metabolites in several forebrain regions after vehicle, APO or AMPH administration. SDH rats were more sensitive than LEH rats to the PPI-disruptive effects of both APO (0.5 mg/kg) and AMPH (4.5 mg/kg). Several significant SDH vs. LEH strain differences in regional neurochemical levels were detected, as were drug effects on these chemicals. However, SDH, LEH and F1 rats did not exhibit differential drug sensitivity in any neurochemical indices measures. These findings suggest that inherited differences in the dopaminergic regulation of sensorimotor gating do not likely reflect differences in presynaptic forebrain dopaminergic or serotonergic processes.

Prevalence of hematozoa in overwintering American redstarts (Setophaga ruticilla): no evidence for local transmission.

We examined American redstarts (Setophaga ruticilla) for protozoan blood parasites on their wintering grounds to determine whether transmission of these parasites occurs prior to spring migration. A total of 73 blood smears from 37 birds were examined for presence and intensity of infection. Thirty-six birds were sampled in the fall, soon after arriving from northern breeding grounds, and the spring prior to departure. Two (5%) of the samples collected in the fall were positive for Haemoproteus fringillae and one (3%) had detectable infections of Trypanosoma avium. Individuals infected with H. fringillae were hatching year redstarts sampled in September and October. Intensity of infection was 78 and < 1 infected erythrocytes per 10,000 erythrocytes, respectively. None of the birds had detectable infections when resampled prior to spring migration the following March.

Sensitivity to drug effects on prepulse inhibition in inbred and outbred rat strains.

Genetic differences in the neurochemical regulation of PPI in rats may help clarify the neural basis of inherited PPI differences in neuropsychiatric disorders. We reported and characterized substantial heritable differences in sensitivity to PPI-disruptive effects of DA agonists in outbred Sprague Dawley (SDH) versus Long-Evans (LEH) rats. Other strains might yield large group separations and facilitate studies of the neural basis for these strain differences; inbred strains might also allow us to map genes associated with differential PPI sensitivity. Sensitivity to the PPI-disruptive effects of the DA agonist apomorphine (APO) and the NMDA antagonist phencyclidine (PCP) were compared across inbred and outbred strains. APO sensitivity was greatest in SDH and buffalo rats, but the effect in buffalo rats was complicated by significant APO-induced startle suppression. PPI APO sensitivity was least in ACI and LEH rats; F344s exhibited intermediate sensitivity and Lewis rats showed a nonlinear dose response (sensitivity at low but not higher doses). PPI APO insensitivity in ACI rats developed over time, with ACI pups exhibiting robust sensitivity. Substantial strain differences were observed in short-interval (10-30 ms) prepulse effects, and APO-induced increases in short-interval PPI occurred in SDH, LEH, and Lewis rats, but not in F344, ACI, or buffalo rats. Sensitivity to PPI-disruptive effects of PCP was generally greater in outbred than inbred rats. These findings identify strains suitable for comparisons of PPI neural circuitry and others for whom such comparisons would be complex and perhaps less informative.

Heritable differences in the effects of amphetamine but not DOI on startle gating in albino and hooded outbred rat strains.

Sensorimotor gating, measured by prepulse inhibition (PPI) of the startle reflex, is reduced in schizophrenia patients and in rats treated with dopamine (DA) agonists. Strain and substrain differences in the sensitivity to the PPI-disruptive effects of DA agonists may provide insight into the basis for human population differences in sensorimotor gating. We reported heritable differences in sensitivity to the PPI-disruptive effects of the D1/D2 agonist apomorphine (APO) in Harlan Sprague-Dawley (SDH) and Long-Evans (LEH) rats, offspring (F1) of an SDHxLEH cross, and subsequent offspring (N2) of an SDHxF1 cross. In this study, we assessed the neurochemical specificity of this heritable phenotype across parental SDH and LEH strains, and their F1 and N2 offspring, based on their sensitivity to the PPI-disruptive effects of the indirect DA agonist D-amphetamine (AMPH) and the 5HT2A agonist DOI. AMPH sensitivity followed a gradient of SDH>N2>F1>LEH, consistent with past findings with APO. DOI sensitivity did not differ across strains or generations. These findings demonstrate that the heritable phenotype in this model is not specific to a particular compound (APO), and reflects physiological differences in the DAergic, but not serotonergic, regulation of PPI.