Altered lipoprotein profiles in cats with hepatic lipidosis.

OBJECTIVES: The aim of this study was to assess serum lipoprotein profiles using rapid single-spin continuous lipoprotein density profiling (CLPDP) in healthy control cats and cats with hepatic lipidosis (HL). METHODS: Analysis of serum lipoprotein profiles using the CLPDP was performed in 23 cats with HL and 20 healthy control cats. The area under the curve for each lipoprotein fraction, triglyceride (TG)-rich lipoproteins (TRLs), low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs), was calculated. Serum cholesterol and TG concentrations were measured using a clinical chemistry analyzer. RESULTS: Serum cholesterol and TG concentrations were not significantly different between healthy control cats and cats with HL ( P = 0.5075 and P = 0.2541, respectively). LDL content was significantly higher in cats with HL than in healthy control cats ( P = 0.0001), while HDL content was significantly lower in cats with HL than in healthy control cats ( P = 0.0032). TRL content was not significantly different between the two groups ( P = 0.0699). The specific fraction (1.037-1.043 g/ml) within nominal LDL in serum distinguished healthy control cats from cats with HL with a sensitivity of 87% and a specificity of 90%. CONCLUSIONS AND RELEVANCE: Serum lipoprotein profiles were altered in cats with HL, even though serum cholesterol and TG concentrations were not significantly different compared with healthy control cats. The CLPDP might be a useful tool for assessing lipid metabolism in cats with HL.

Evaluation of density gradient ultracentrifugation serum lipoprotein profiles in healthy dogs and dogs with exocrine pancreatic insufficiency.

Changes in proportions of lipoprotein classes have been described in disease states in humans. In veterinary medicine, hyperlipidemia can cause complications, such as cutaneous xanthomas, liver disease, cholelithiasis, pancreatitis, glomerular disease, lipemia retinalis, or peripheral neuropathy, but there are few reports regarding lipoproteins in diseased animals. For canine serum, we partially validated continuous lipoprotein density profiling (CLPDP), a novel density gradient ultracentrifugation technique. We examined canine lipoproteins separated by CLPDP by transmission electron microscopy (TEM). We compared lipoprotein profiles between healthy control dogs ( n = 29) and dogs with exocrine pancreatic insufficiency (EPI; n = 28) using CLPDP. Dogs with EPI included those untreated (EPI-NT; n = 6) and those treated with enzyme supplementation (EPI-T; n = 22). Our preliminary assay validation showed that CLPDP was repeatable (CV = 11.2%) and reproducible (CV = 10.6%) in canine serum. The diameters of lipoproteins analyzed by TEM were similar to those reported previously. Dogs in the EPI-NT group had more severe dyslipidemia than dogs in the EPI-T group. Dogs in the EPI-T group had lipoprotein profiles similar to healthy control dogs. CLPDP might be a useful tool for evaluating dyslipidemia in dogs.

Expression of the Bovine NK-Lysin Gene Family and Activity against Respiratory Pathogens.

Unlike the genomes of many mammals that have a single NK-lysin gene, the cattle genome contains a family of four genes, one of which is expressed preferentially in the lung. In this study, we compared the expression of the four bovine NK-lysin genes in healthy animals to animals challenged with pathogens known to be associated with bovine respiratory disease (BRD) using transcriptome sequencing (RNA-seq). The expression of several NK-lysins, especially NK2C, was elevated in challenged relative to control animals. The effects of synthetic peptides corresponding to functional region helices 2 and 3 of each gene product were tested on both model membranes and bio-membranes. Circular dichroism spectroscopy indicated that these peptides adopted a more helical secondary structure upon binding to an anionic model membrane and liposome leakage assays suggested that these peptides disrupt membranes. Bacterial killing assays further confirmed the antimicrobial effects of these peptides on BRD-associated bacteria, including both Pasteurella multocida and Mannhemia haemolytica and an ultrastructural examination of NK-lysin-treated P. multocida cells by transmission electron microscopy revealed the lysis of target membranes. These studies demonstrate that the expanded bovine NK-lysin gene family is potentially important in host defense against pathogens involved in bovine respiratory disease.

Congenital dystrophic epidermolysis bullosa (DEB) in Sprague Dawley rats: a case series.

BACKGROUND: Epidermolysis bullosa is a rare skin disease caused by defects in the basement membrane and/or other dermoepidermal junction components. HYPOTHESIS/OBJECTIVES: We describe a series of spontaneous cases of dystrophic epidermolysis bullosa (DEB) in a colony of Sprague Dawley rats investigated with histopathology, transmission electron microscopy (TEM) and inheritance pattern. ANIMALS: Four, 4-day-old pups from a litter of Sprague Dawley rats developed blistering, haemorrhagic skin lesions and were euthanized. Age-matched controls from the same litter were normal. Several months later two more litters presented with identical findings. All three litters had the same sire, suggesting a genetic component. METHODS: Skin from affected and control animals was evaluated histologically and with TEM. Unaffected sibling pairs from affected litters were bred in order to potentially reproduce the disease and determine the mode of inheritance. RESULTS: Histologically, there was significant dermoepidermal clefting below the basement membrane with variable amounts of haemorrhage and cellular debris within the clefts. Ultrastructurally, clefting occurred below the basement membrane with an intact lamina densa and normal hemidesmosomes. Anchoring filaments were strikingly absent. Litters produced from phenotypically unaffected sibling pairs resulted in a total of four more litters with approximately a quarter of pups affected. CONCLUSIONS AND CLINICAL IMPORTANCE: Based on the gross lesions, histopathological features and TEM determination of separation below the lamina densa and lack of normal anchoring fibrils, these cases are most consistent with DEB. This is the first report of naturally occurring, localized and reproducible recessive DEB in Sprague Dawley rats.

Physical and functional interaction of Acyl-CoA-binding protein with hepatocyte nuclear factor-4 alpha.

Although acyl-CoA-binding protein (ACBP) has been detected in the nucleus, the physiological significance of this observation is unknown. As shown herein for the first time, ACBP in the nucleus physically and functionally interacted with hepatocyte nuclear factor-4 alpha (HNF-4 alpha), a nuclear binding protein that regulates transcription of genes involved in both lipid and glucose metabolism. Five lines of evidence showed that ACBP bound HNF-4 alpha in vitro and in the nucleus of intact cells. (i) ACBP interaction with HNF-4 alpha elicited significant changes in secondary structure. (ii) ACBP and HNF-4 alpha were coimmunoprecipitated by antibodies to each protein. (iii) Double immunolabeling and laser scanning confocal microscopy (LSCM) of rat hepatoma cells and transfected COS-7 cells significantly colocalized ACBP and HNF-4 alpha within the nucleus and in the perinuclear region close to the nuclear membrane. (iv) LSCM fluorescence resonance energy transfer determined an intermolecular distance of 53 A between ACBP and HNF-4 alpha in rat hepatoma cell nuclei. (v) Immunogold electron microscopy detected ACBP within 43 A of HNF-4 alpha. These interactions were specific since ACBP did not interact with Sp1 or glucocorticoid receptor in these assays. The functional significance of ACBP interaction with HNF-4 alpha was evidenced by mammalian two-hybrid and transactivation assays. ACBP overexpression in COS-7 or rat hepatoma cells enhanced transactivation of an HNF-4 alpha-dependent luciferase reporter plasmid by 3.2- and 1.6-fold, respectively. In contrast, cotransfection with antisense ACBP expression vector inhibited transactivation. LSCM of the individual triple fluorescent-labeled (HNF-4 alpha, ACBP, and luciferase) rat hepatoma cells showed a high correlation (r2, 0.936) between the level of luciferase and the level of ACBP expression. In summary, ACBP physically interacted with HNF-4 alpha in vitro and in intact cells, although ACBP expression level directly correlated with HNF-4 alpha-mediated transactivation in individual cells.