Lipoprotein cholesterol and triglyceride concentrations associated with dog body condition score; effect of recommended fasting duration on sample concentrations in Japanese private clinics

Clustering analysis of lipoprotein profiles to identify subtypes of hypertriglyceridemia in Miniature Schnauzers

BACKGROUND

Hypertriglyceridemia (HTG) is prevalent in Miniature Schnauzers, predisposing them to life-threatening diseases. Varied responses to management strategies suggest the possibility of multiple subtypes.

HYPOTHESIS/OBJECTIVE

To identify and characterize HTG subtypes in Miniature Schnauzers through cluster analysis of lipoprotein profiles. We hypothesize that multiple phenotypes of primary HTG exist in this breed.

ANIMALS

Twenty Miniature Schnauzers with normal serum triglyceride concentration (NTG), 25 with primary HTG, and 5 with secondary HTG.

METHODS

Cross-sectional study using archived samples. Lipoprotein profiles, generated using continuous lipoprotein density profiling, were clustered with hierarchical cluster analysis. Clinical data (age, sex, body condition score, and dietary fat content) was compared between clusters.

RESULTS

Six clusters were identified. Dogs with primary HTG were dispersed among 4 clusters. One cluster showed the highest intensities for triglyceride-rich lipoprotein (TRL) and low-density lipoprotein (LDL) fractions and also included 4 dogs with secondary HTG. Two clusters had moderately high TRL fraction intensities and low-to-intermediate LDL intensities. The fourth cluster had high LDL but variable TRL fraction intensities with equal numbers of NTG and mild HTG dogs. The final 2 clusters comprised only NTG dogs with low TRL intensities and low-to-intermediate LDL intensities. The clusters did not appear to be driven by differences in the clinical data.

CONCLUSIONS AND CLINICAL IMPORTANCE

The results of this study support a spectrum of lipoprotein phenotypes within Miniature Schnauzers that cannot be predicted by triglyceride concentration alone. Lipoprotein profiling might be useful to determine if subtypes have different origins, clinical consequences, and response to treatment.

Lipoprotein profiles in Miniature Schnauzer dogs with idiopathic hypertriglyceridemia and hypercortisolism

Miniature Schnauzer dogs (MSs) are predisposed to both idiopathic hypertriglyceridemia (iHTG) and hypercortisolism (HCort). To our knowledge, the lipoprotein profiles of MSs with iHTG have not been compared to those with HCort. We analyzed cholesterol and triglyceride concentrations and lipoprotein fractions in 4 groups of MSs: normotriglyceridemia (NTG) without concurrent disease (Healthy-NTG), HCort and NTG (HCort-NTG), HCort and HTG (HCort-HTG), and iHTG. Lipoprotein fractions were assessed by lipoprotein electrophoresis and compared between groups. Fifty-one plasma samples were analyzed. Twenty-five dogs had NTG (16 Healthy-NTG, 9 HCort-NTG) and 26 dogs had HTG (7 iHTG, 19 HCort-HTG). Dogs with iHTG or HCort-HTG had significantly higher cholesterol concentrations than Healthy-NTG dogs. Dogs with HCort-HTG had higher cholesterol than HCort-NTG dogs. There was a significantly higher low-density lipoprotein (LDL) percentage in iHTG and HCort-HTG dogs than HCort-NTG dogs. HCort-HTG dogs also had lower high-density lipoproteins (HDL) than HCort-NTG dogs. It was not possible to readily distinguish MSs with iHTG from MSs with HCort-HTG or Healthy-NTG using lipoprotein electrophoresis fractions. The diagnosis of iHTG remains a diagnosis by exclusion.

Seroprevalence, Blood Chemistry, and Patterns of Canine Parvovirus, Distemper Virus, Plague, and Tularemia in Free-Ranging Coyotes (Canis latrans) in Northern New Mexico, USA

Wildlife diseases have implications for ecology, conservation, human health, and health of domestic animals. They may impact wildlife health and population dynamics. Exposure rates of coyotes (Canis latrans) to pathogens such as Yersinia pestis, the cause of plague, may reflect prevalence rates in both rodent prey and human populations. We captured coyotes in north-central New Mexico during 2005-2008 and collected blood samples for serologic surveys. We tested for antibodies against canine distemper virus (CDV, Canine morbillivirus), canine parvovirus (CPV, Carnivore protoparvovirus), plague, tularemia (Francisella tularensis), and for canine heartworm (Dirofilaria immitis) antigen. Serum biochemistry variables that fell outside reference ranges were probably related to capture stress. We detected antibodies to parvovirus in 32/32 samples (100%), and to Y. pestis in 26/31 (84%). More than half 19/32 (59%) had antibodies against CDV, and 5/31 (39%) had antibodies against F. tularensis. We did not detect any heartworm antigens (n = 9). Pathogen prevalence was similar between sexes and among the three coyote packs in the study area. Parvovirus exposure appeared to happen early in life, and prevalence of antibodies against CDV increased with increasing age class. Exposure to Y. pestis and F. tularensis occurred across all age classes. The high coyote seroprevalence rates observed for CPV, Y. pestis, and CDV may indicate high prevalence in sympatric vertebrate populations, with implications for regional wildlife conservation as well as risk to humans via zoonotic transmission.

Effect of withholding food versus feeding on creatinine, symmetric dimethylarginine, cholesterol, triglycerides, and other biochemical analytes in 100 healthy dogs

BACKGROUND

Withholding food is often recommended before collection of blood for routine biochemical analysis in dogs despite a paucity of evidence to support this requirement.

OBJECTIVES

To compare measurements of selected biochemical analytes collected before and after feeding in clinically healthy dogs.

ANIMALS

One hundred clinically healthy staff- and student-owned dogs weighing ≥15 kg.

METHODS

Prospective observational study. Food was withheld from the dogs for 10-26 hours. Preprandial serum was collected, and then dogs were fed their usual food at an amount equivalent to at least 2/3 resting energy requirement (RER). Selected serum analytes were measured at 2-, 4-, 6-, and 8-hours postprandially. The proportion of postprandial values that exceeded either the reported allowable total error (TEa), or for symmetric dimethylarginine (SDMA), the reference change value (RCV), was determined. As neither TEa nor RCV is available for lipase, comparison was made to the high end of the reference interval (RI).

RESULTS

The proportion of dogs with at least 1 postprandial measurement that exceeded the TEa or RCV was 92/100 for triglycerides, 66/100 for blood urea nitrogen (BUN), 46/100 for phosphorus, 17/100 for glucose, 9/100 for bilirubin, 5/100 for SDMA, 2/100 for creatinine, and 0/100 for cholesterol and albumin. Postprandial lipase never exceeded the RI in dogs with normal fasted lipase.

CONCLUSIONS AND CLINICAL IMPORTANCE

Withholding food is generally not necessary before performing routine biochemical analysis in clinically healthy dogs. Withholding food might be helpful to limit variability in analytes impacted by feeding, such as triglycerides and phosphorus.

Evaluation of circulating extracellular vesicles and miRNA in neutered and obese female dogs

Adipose tissue is a metabolic and endocrine organ, and its adipocytes can synthesize and secrete extracellular vesicles (EVs), thus allowing intercellular communication. EVs are nanoparticles that transport lipids, proteins, metabolites, and nucleic acids (mRNA and microRNAs). MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression. miR-132, miR-26b, and miR-155 are associated with obesity, lipid metabolism and adipogenesis. The aim of this study was to evaluate the enriched EVs fraction containing miRNAs (miR-132, miR-26b, and miR-155) in serum from obese female dogs. Thirty-two neutered females in good general condition were recruited, including 21 obese and 11 healthy controls. The initial evaluation of the females included a general physical examination and laboratory tests. Small EVs (sEVs) were isolated from whole blood by serial centrifugation and ultracentrifugation, and nanoparticle analysis was used to determine the size and concentration of serum sEVs. miRNAs were extracted from sEVs enriched fraction and analyzed by real-time polymerase chain reaction. Obese female dogs with hypertriglyceridemia showed an increase in the sEVs concentration and in the expression of miR-132 and miR-26b in sEVs enriched fraction. No changes were observed in the group of obese female dogs with normal serum biochemical profile and in relation to miR-155 expression. These results suggest that obese female dogs with hypertriglyceridemia may present alterations in sEVs and in the expression of miRNAs related to lipid metabolism and adipogenesis.

Association between serum miRNAs and gingival gene expression in an obese rat model

INTRODUCTION

Recent studies have reported a relationship between periodontitis and obesity; however, the mechanisms of obesity's effects on periodontitis are not well understood. On the other hand, microRNAs (miRNAs) are known to play key roles in the post-transcriptional regulation gene expression by suppressing translation and protein synthesis. We examined the association between obesity-related miRNAs and gene expression in gingival tissue using miRNA-messenger RNA (mRNA) pairing analysis in an obese rat model.

METHODS

Sixteen male Wistar rats aged 8 weeks old were divided into two groups: the control group was fed a normal powdered food for 8 weeks, and the obesity group was fed a high-fat diet for 8 weeks. Distance from the cement-enamel junction to the alveolar bone crest of the first molars was measured. miRNA microarray analysis was performed on samples of serum and gingival tissue; the resulting data were used to calculate fold changes in miRNA levels in the obesity group relative to the control group, and miRNA-mRNA pairing analysis was performed to identify mRNAs potentially targeted by miRNAs of interest.

RESULTS

Alveolar bone loss in the obesity group exceeded that in the control group (p = .017). miRNA-mRNA pairing analysis identified an association between 4 miRNAs (miR-759, miR-9a-3p, miR-203b-3p, and miR-878) that were differentially expressed in the obesity and control groups and 7 genes (Ly86, Arid5b, Rgs18, Mlana, P2ry13, Kif1b, and Myt1) expressed in gingival tissue.

CONCLUSION

This study revealed that several miRNAs play an important role in the mechanism of periodontal disease progression induced by the obesity.

Research-Relevant Clinical Pathology Resources: Emphasis on Mice, Rats, Rabbits, Dogs, Minipigs, and Non-Human Primates

Clinical pathology testing for investigative or biomedical research and for preclinical toxicity and safety assessment in laboratory animals is a distinct specialty requiring an understanding of species specific and other influential variables on results and interpretation. This review of clinical pathology principles and testing recommendations in laboratory animal species aims to provide a useful resource for researchers, veterinary specialists, toxicologists, and clinical or anatomic pathologists.

Improvement Effect of 5-Aminolevulinic Acid on Hyperlipidemia in Miniature Schnauzer Dogs: An Open Study in 5 Cases of One Pedigree

This is the first study to examine the long-term effect of 5-aminolevulinic acid mainly on serum lipoproteins in dogs with hyperlipidemia. We studied 5 Miniature Schnauzer cases whose fasting serum total triglyceride and very-low-density lipoprotein of triglyceride levels were extremely high (635 ± 116 and 520 ± 92 mg/dL, respectively). Although the total cholesterol values were normal, the very-low-density lipoprotein of cholesterol level was high (49 ± 7 mg/dL). Each dog received a 5-aminolevulinic acid supplement (5 mg/day) orally for 6 months. The mean values of total triglyceride, very-low-density lipoprotein of both triglyceride and cholesterol decreased significantly after the treatment period (319 ± 29, 245 ± 18, and 27 ± 2 mg/dL, respectively, P < 0.05). Our present results may present evidence that 5-ALA administration contributes to improvement of hyperlipidemia in Miniature Schnauzer.

Clinofibrate improved canine lipid metabolism in some but not all breeds

The objectives of this study were to assess if Clinofibrate (CF) treatment improved lipid metabolism in dogs, and to clarify whether its efficacy is influenced by canine characteristics. We collected medical records of 306 dogs and performed epidemiological analyses. Lipid values of all lipoproteins were significantly decreased by CF medication, especially VLDL triglyceride (TG) concentration (mean reduction rate=54.82%). However, 17.65% of dogs showed drug refractoriness in relation to TG level, and Toy Poodles had a lower CF response than other breeds (OR=5.36, 95% CI=2.07-13.90). Therefore, our study suggests that genetic factors may have an effect on CF response, so genetic studies on lipid metabolism-related genes might be conducted to identify variations in CF efficacy.

Spectrophotometry and Ultracentrifugation for Measurement of Plasma Lipids in Dogs with Diabetes Mellitus

Background

There are conflicting reports of plasma lipoprotein lipid content in dogs with diabetes mellitus (DM).

Objectives

To determine lipoprotein lipid content of plasma of dogs with DM by spectrophotometry and ultracentrifugation; to compare lipoprotein lipid content in diabetic and healthy dogs; and to quantify apolipoprotein B‐100 (ApoB) in dogs with DM.

Animals

22 dogs with DM and 9 healthy dogs.

Methods

Cross‐sectional study. Triglyceride (TG), total cholesterol (TC), and high‐density lipoprotein cholesterol (HDL‐C) concentrations were measured by spectrophotometry. Very low‐density lipoprotein cholesterol (VLDL‐C) and low‐density lipoprotein cholesterol (LDL‐C) concentrations were calculated after ultracentrifugation. Non‐HDL‐C cholesterol was calculated by subtracting HDL‐C from TC. ApoB was quantified by ELISA. The Mann‐Whitney test was used for comparison of median lipoprotein concentrations, and Spearman's correlation was used to assess associations between ApoB and lipoprotein fractions.

Results

All values are reported in mg/dL. Median TG (122), TC (343.5), HDL‐C, (200), VLDL‐C, (27) LDL‐C (68), non‐HDL‐C (114), and ApoB (320) were significantly higher in dogs with DM, compared to healthy dogs (57, 197, 168, 12, 16, 31, and 258, respectively, P‐values 0.0079, <0.001, 0.029, 0.011, <0.001, <0.001, 0.025, respectively). A significant association was found between ApoB and LDL‐C (Spearman's rho = 0.41, P = 0.022) and between ApoB and non‐HDL‐C (Spearman's rho = 0.40, P = 0.027).

Conclusions and Clinical Importance

Dyslipidemia of dogs with DM is characterized by pronounced increases in LDL‐C and non‐HDL‐C concentrations, although all lipoprotein fractions are significantly increased. Knowledge of specific lipoprotein fraction alterations in dogs with DM can enhance treatment options for diabetic dyslipidemia in dogs.

Preventive Effects of Drinking Hydrogen-Rich Water on Gingival Oxidative Stress and Alveolar Bone Resorption in Rats Fed a High-Fat Diet

Obesity induces gingival oxidative stress, which is involved in the progression of alveolar bone resorption. The antioxidant effect of hydrogen-rich water may attenuate gingival oxidative stress and prevent alveolar bone resorption in cases of obesity. We examined whether hydrogen-rich water could suppress gingival oxidative stress and alveolar bone resorption in obese rats fed a high-fat diet. Male Fischer 344 rats (n = 18) were divided into three groups of six rats each: a control group (fed a regular diet and drinking distilled water) and two experimental groups (fed a high-fat diet and drinking distilled water or hydrogen-rich water). The level of 8-hydroxydeoxyguanosine was determined to evaluate oxidative stress. The bone mineral density of the alveolar bone was analyzed by micro-computerized tomography. Obese rats, induced by a high-fat diet, showed a higher gingival level of 8-hydroxydeoxyguanosine and a lower level of alveolar bone density compared to the control group. Drinking hydrogen-rich water suppressed body weight gain, lowered gingival level of 8-hydroxydeoxyguanosine, and reduced alveolar bone resorption in rats on a high-fat diet. The results indicate that hydrogen-rich water could suppress gingival oxidative stress and alveolar bone resorption by limiting obesity.