Canine serum protein patterns using high-resolution electrophoresis (HRE)

Serum Protein Concentration and Serum Protein Fractions in Bottlenose Dolphins (Tursiops truncatus) under Human Care Using Agarose Gel Electrophoresis

Serum protein electrophoresis (SPE) is the most used and reliable method to determine the percentage of serum protein subfractions. The interpretation of the kinetics of total proteins and albumin and globulin fractions is receiving increased attention in wild animals, as well as in domestic animals, due to the possibility of identifying typical pathologic patterns. However, the interpretation of these data had to be performed in light of an appropriate method-and species- specific reference intervals (RIs). In marine mammals, as well as other non-domestic species, specific attention should also be given to the different environment (free ranging vs. human managed) and the associated different exposure to environmental stimuli. The aim of this report was to establish RIs for the serum protein fractions evaluated using agarose gel electrophoresis (AGE) in bottlenose dolphins under human care. Peripheral blood samples were collected from 40 bottlenose dolphins during standard veterinary procedures to evaluate their health status. Total protein concentration was determined using the biuret method while AGE was performed using an automated system. A pooled dolphin's serum sample was used to determine the intra-assay and inter-assay imprecision of AGE. The RIs were calculated using an Excel spreadsheet with the Reference Value Advisor set of macroinstructions. The intra and inter-assay imprecisions were 1.2% and 2.5%, respectively, for albumin; 2.9% and 5.7%, respectively, for α-globulins; 3.8% and 4.0%, respectively, for β-globulins; and 3.4% and 4.8%, respectively, for γ-globulins. The total protein, albumin, α-globulin, β-globulin, and γ-globulin concentrations were 65.5 ± 5.4 g/L, 45.5 ± 4.9 g/L, 8.0 ± 1.0 g/L, 5.0 ± 2.0 g/L, and 7.0 ± 2.0 g/L, respectively. We established the RIs for the total protein and serum protein fractions using AGE in bottlenose dolphins under human care.

Validation and method comparison of the use of densitometry to quantify monoclonal proteins in canine sera

BACKGROUND

Densitometric quantitation using serum protein electrophoresis (SPE) is used to monitor monoclonal proteins (M-proteins) in human patients but has not been validated in the dog. Serum globulin concentrations, species-specific radial immunodiffusion (RID), and ELISAs are currently used in veterinary medicine.

OBJECTIVE

We aimed to compare four methods that quantify M-proteins using densitometry and biuret protein (dM-protein) measurements. We also validated the best performing method and compared it with the RID and ELISA methods for measuring canine serum M-protein.

METHOD

Serum from six normal dogs and 83 serum samples from 46 dogs with confirmed monoclonal gammopathies were used. A spike and recovery experiment with purified monoclonal IgG and IgM, inter-run and intra-run variability, linearity under dilution, and lower limit of detection were performed. Results of commercial canine RID and ELISA kits for total class-specific immunoglobulin were compared with dM-proteins.

RESULTS

The corrected perpendicular drop gating method had <20% error for IgG/γ-globulin and IgM/β-globulin M-protein quantifications. Linearity (r > .99), intra-run CV (1.1%-2.3%), and inter-run CVs (2.0%-3.5%) were acceptable. Correlation between the RID and densitometry results ranged from r = .25 to r = .88, depending on the class. The RID result was greater than that of the biuret total protein in 26/63 (41%) IgA cases. A panel of IgG, IgA, and IgM RIDs failed to correctly identify an IgM paraproteinemia in 6/6 (100%) cases. Densitometry was not comparable with any other tested method.

CONCLUSION

Densitometric quantitation is a valid technique for measuring M-proteins in the β- and γ-globulin regions. Immunotyping via RID using the tested kit does not appear to detect IgM. Densitometry is recommended for measuring M-proteins in canine patients.

Protein characterization using electrophoresis and immunofixation; a case-based review of dogs and cats

Protein electrophoresis and immunotyping can be a useful adjunct to the standard biochemical techniques for characterizing serum and urine proteins. This paper reviews currently available and commonly used methods for diagnostic protein electrophoresis, including both agarose gel and capillary zone electrophoretic techniques and total protein assessments. Immunofixation and immunosubtraction methods for identification of immunoglobulin location and class are also presented. Practical application of quality assurance and quality control strategies in compliance with American Society of Veterinary Clinical Pathology (ASVCP) best practices are discussed. Commonly encountered serum and urine electrophoretic diagnostic patterns, including electrophoretically normal, acute-phase protein responses, polyclonal gammopathies, restricted polyclonal/oligoclonal gammopathies, paraproteinemias (monoclonal or biclonal gammopathies), and Bence-Jones proteinurias are also reviewed using relevant case material. Cases in which immunofixation electrophoresis are particularly useful are highlighted, and methodologies to more accurately quantify serum monoclonal proteins (M-proteins), monitoring tests commonly used in human medicine, are discussed.

The electrophoretic pattern of serum proteins in dairy cows with inflammatory diseases

The objective of the study was to evaluate the electrophoretic pattern of serum proteins in dairy cows suffering from various inflammatory diseases, and to study the influence of these diseases on the concentrations of protein fractions. Fourty dairy cows with clinical signs of various inflammatory diseases were used in the study, including cows with post-partum metritis (n=10), mastitis (n=7), and hoof diseases (n=23). The cows were of a black pied Holstein-Friesian breed, Slovak spotted breed and their crossbreeds at the age of 3.5 to 8 years. Fourteen clinically healthy dairy cows were taken as the control group. The cows were blood sampled for the determination of total serum proteins and serum protein fractions. The protein fractions were divided into albumin, α1-, α2-, β1-, β2-, and γ-globulins. In cows with post-partum metritis we found significantly lower concentrations of albumin (P<0.001) and significantly higher values of α1-globulins (P<0.01) compared with healthy animals. Significantly higher concentrations of β1-globulins were observed in cows with mastitis (P<0.001), while the γ-globulin fraction was non-significantly higher. In cows with hoof diseases we recorded significantly lower values of albumin (P<0.001), significantly higher concentrations of α1- and β1-globulins (P<0.001), and non-significantly higher β2- and γ-globulins. Moreover, in the electrophoretic pattern of serum proteins we found β-γ bridging in thirteen cows with hoof diseases. Presented data suggest marked influence of inflammatory diseases on the concentrations of serum protein fractions in dairy cows. However, further investigations are needed to establish the diagnostic utility of serum protein electrophoresis in bovine clinical practice in relation to inflammatory diseases.

Serum lipoprotein changes in dogs with renal disease

Background

People with renal disease develop a dyslipidemia that contributes to progression of renal injury and development of cardiovascular disease. Lipoproteins in dogs with renal disease have not been investigated.

Hypothesis

Dogs with chronic kidney disease (CKD) have dyslipidemia characterized by increased lower density lipoproteins and decreased high‐density lipoproteins (HDLs). The degree of dyslipidemia is positively correlated with severity of disease, as reflected by serum creatinine concentration.

Animals

Prospective study of client‐owned dogs presented to the Cornell University Hospital for Animals: 29 dogs with confirmed CKD, 5 dogs with nephrotic syndrome (NS), and 12 healthy control dogs presented for routine vaccinations, dental cleaning, or owned by students.

Methods

Lipoprotein electrophoresis was used to quantify relative proportions of the 3 main classes of lipoproteins in canine serum: low‐density lipoproteins (LDL), very low‐density lipoproteins (VLDL), and HDL. Serum cholesterol and creatinine concentrations; urinalysis and urine protein‐to‐creatinine ratio were measured by standard methods.

Results

Dyslipidemia was consistently found in dogs with CKD and NS and was characterized by a decrease in HDL and variable increases in LDL and VLDL. Dogs with NS had a proportionately greater increase in the VLDL fraction, as compared with dogs with CKD.

Conclusion and Clinical Importance

Dyslipidemia similar to that documented in people with renal disease occurs in dogs with CKD, despite serum cholesterol concentrations often being within the reference interval. The contribution of altered lipoproteins to the pathogenesis of renal disease in dogs warrants additional study.

LC-MS/MS analysis of canine lipoproteins fractionated using the ultracentrifugation-precipitation method

Due to the lack of a gold standard method in canine lipoprotein analysis, it is unclear whether canine high-density lipoprotein (HDL) and low-density lipoprotein (LDL) can be accurately evaluated by the lipoprotein analysis methods used for dogs. This study investigated whether the ultracentrifugation-precipitation (U-P) method was suitable as a gold standard method for analyzing canine lipoprotein. First, the U-P method was compared with a gel permeation high-performance liquid chromatography system (GP-HPLC). The concentrations of canine HDL cholesterol (HDL-C) and LDL cholesterol (LDL-C) determined by the U-P method correlated closely with those determined by GP-HPLC. However, the canine HDL-C concentration determined by the U-P method was lower than that determined by GP-HPLC, and the canine LDL-C concentration determined by the U-P method was higher than that determined by GP-HPLC. This study showed that some canine HDL could be precipitated with heparin manganese chloride solution. Second, the HDL and LDL fractions separated by the U-P method were analyzed by LC-MS/MS. The HDL fraction was found to contain only apolipoprotein A-I, which is an apolipoprotein of HDL, whereas the LDL fraction contained both apolipoprotein A-I and apolipoprotein B-100, which is an apolipoprotein of LDL. This data showed that a certain lipoprotein that includes apolipoprotein A-I might precipitate with canine LDL when using heparin manganese chloride solution. These results indicated that the U-P method is not currently a gold standard method for analyzing canine lipoproteins.

Bovine and canine transferrin inhibit the growth of Malassezia pachydermatis in vitro

Transferrin, an iron-binding beta-globulin protein that transports iron to mammalian cells, may contribute to innate immunity to fungal pathogens, primarily by limiting microbial access to iron. We investigated whether unsaturated (apo) canine and bovine transferrin had an inhibitory effect in vitro on Malassezia pachydermatis, an important opportunistic cutaneous yeast pathogen of dogs. M. pachydermatis strains were grown at 32 degrees C in 96-well culture plates using Sabouraud's liquid medium containing canine or bovine apo-transferrin at concentrations ranging from 10.6 to 0.7 mg/ml. Optical densities (OD492) in the treated and control wells were measured and then compared between treatments. Bovine and canine transferrin inhibited (P < 0.01) yeast growth at all concentrations tested after five and six days of incubation; inhibition by 5.3 mg/ml exceeded (P < 0.05) that of 0.7 mg/ml on day six. Unsaturated and saturated bovine transferrin had comparable inhibitory effects on the growth of four strains, indicating that the inhibitory effects of transferrin on M. pachydermatis are not dependent upon iron depletion. These studies suggest that transferrin may contribute to innate immunity to M. pachydermatis in dogs and cattle.

Current research on acute phase proteins in veterinary diagnosis: an overview

The acute phase proteins (APP) are a group of blood proteins that contribute to restoring homeostasis and limiting microbial growth in an antibody-independent manner in animals subjected to infection, inflammation, surgical trauma or stress. In the last two decades, many advances have been made in monitoring APP in both farm and companion animals for clinical and experimental purposes. Also, the mechanism of the APP response is receiving attention in veterinary science in connection with the innate immune systems of animals. This review describes the results of recent research on animal APP, with special reference to their induction and regulatory mechanisms, their biological functions, and their current and future applications to veterinary diagnosis and animal production.

Effects of haemolysis, lipaemia, bilirubinaemia and fibrinogen on protein electropherogram of canine samples analysed by capillary zone electrophoresis

The possible interference of haemolysis, lipaemia, bilirubinaemia and fibrinogen on capillary zone electrophoresis of canine samples were studied. Solutions of haemoglobin, lipid and bilirubin were prepared and mixed with serum aliquots to make up samples containing different concentrations of the putative interferent substance. In addition, samples of serum and plasma were assayed to assess the influence of fibrinogen. Haemolysis and lipids produced a change in electropherogram morphology giving an interference peak located in the beta-2 region when haemoglobin was increased, and in the alpha-2 region when lipids were increased. A rise in concentration of these interferents caused an increase in the beta and alpha-2 fractions respectively, and a decrease in the other fractions. Bilirubin did not alter morphology but gave an increase in the albumin and alpha-1 and a decrease in the alpha-2 and beta-2 fractions. No differences were found between serum and plasma samples, and fibrinogen did not produce any additional peak.

Overestimation of canine albumin concentration with the bromcresol green method in heparinized plasma samples

Albumin concentrations are routinely measured in dogs with bromcresol green (BCG)-binding assays on automated chemistry analyzers. Several variables affect this assay, including the length of reaction time, sample type, and lack of specificity of BCG for albumin. We observed that albumin concentrations measured with BCG appeared higher in heparinized plasma samples in sick dogs. The objective of this study was to determine the effect of anticoagulant and assay procedure on BCG albumin concentrations in clinically ill dogs. We hypothesized that albumin concentrations would be overestimated in heparinized plasma compared with serum because of the combination of heparin and fibrinogen. Furthermore, we hypothesized that the overestimation would be influenced by assay parameters. Blood was collected from 32 clinically ill dogs into tubes containing heparin, citrate, or no anticoagulant. Citrate was chosen to assess the effect of fibrinogen in the absence of heparin. Albumin concentration was measured in all 3 sample types from each dog using 2 different BCG procedures on an automated chemistry analyzer. The BCG procedures (standard and modified) differed in the wavelengths used for absorbance readings (standard, 600/700; modified, 570/505) and the time point at which absorbance was measured (standard, 100 seconds; modified, 40 seconds). In addition, the modified method incorporated a sample blank. Globulin fractions, fibrinogen concentration, and indices of lipemia, hemolysis, and icterus were evaluated for their contribution to the overestimation of albumin concentration in heparinized plasma compared with serum samples. Albumin concentrations were significantly higher (P </=.05) in heparinized plasma (mean +/- SE, 3.8 +/- 0.1 g/dL) than in serum (3.6 +/- 0.2 g/dL) or citrated plasma (3.2 +/- 0.1 g/dL). Overestimation was evident only with the standard BCG procedure. Multiple linear regression analysis indicated that fibrinogen was largely responsible for the higher albumin concentration in heparinized plasma with the standard method. Based on these results, heparin is not recommended as an anticoagulant for albumin measurement in dogs when using a BCG method unless the assay uses a sample blank and a reaction time of <1 minute.