Cholesterol concentrations in lipoprotein fractions separated by anion-exchange–high-performance liquid chromatography in healthy dogs and dogs with hypercholesterolemia

A Pilot Study of the Total Cholesterol/High-Density Lipoprotein Ratio as a Prognostic Indicator of Hyperlipidemia-Related Diseases in Dogs and Cats

In veterinary medicine, the significance of high-density lipoprotein (HDL) measurements is not as well documented as it is in humans. The HDL level can be measured in dogs as well and, through referring to the normal range, it is possible to find out what this means in relation to various endocrine diseases and hyperlipidemia diseases. The aim of this study is to measure the HDL levels in dogs with various conditions and to evaluate whether the total cholesterol (TC)-to-HDL ratio is effective as a prognostic indicator in various hyperlipidemia and endocrine diseases, which is significant since it is the first trial in dogs. Through a retrospective study design, sixteen client-owned dogs and cats visiting a local private practice were divided into three groups: five dogs without hyperlipidemia or metabolic disease (Group 1), eight dogs with Cushing's, hypothyroidism, and gallbladder sludge (Group 2), and three cats, including one with diabetes, one with a urinary disorder, and one healthy cat (Group 3). In two dogs, the TC/HDL values were between 2 and 3; in two dogs, the values were between 3 and 4; and in two dogs, the values were between 4 and 5. In three dogs, the TC/HDL values were between 5 and 6 and in three dogs the ratio values were between 6 and 7. The other value was higher than 8. Except for two dogs that showed lower values than 3, all dogs in Group 1 and Group 2 had concurrent endocrine disease. This means that TC/HDL values can be an excellent indicator of endocrine disease in dogs as well. In cats, although it is a very small batch of samples, a high TC/HDL value of 9 points was shown in the cat that had diabetes mellitus. However, for more statistically significant results, a larger sample group for further investigation is needed.

Treatment of Ezetimibe lowers total and low-density lipoprotein cholesterol in hypercholesterolemic dogs with hyperadorenocorticism

Ezetimibe is a cholesterol absorption inhibitor that blocks the intestinal absorption of both biliary and dietary cholesterol, thereby lowering primarily low density lipoprotein-cholesterol (LDL-chol) in human studies. This study aimed to investigate the effects of ezetimibe on dyslipidemia control in nine dogs with hypercholesterolemia. Changes in total cholesterol (T-chol) and each lipoprotein fractions were evaluated at 0, 2, and 4 months following initiation of ezetimibe treatment. A significant decrease in T-chol was observed, and a mean T-chol concentration below 400 mg/dL was achieved at 2 and 4 months. Furthermore, a significant decrease in LDL-chol was observed (-53.3% and -64.3% at 2 and 4 months, respectively). Taken together, treatment of ezetimibe could lower LDL-chol levels in dogs with hypercholesterolemia.

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.

Effect of phytosterols on reducing low-density lipoprotein cholesterol in dogs

Hyperlipidemia is described as an increase in serum and/or plasma levels of triglycerides, cholesterol, or both. This disturbance can be primary in some cases, or combined with other comorbidities such as endocrinopathies, liver diseases, or specific drug use. Among the various ways to control dyslipidemia are specific diets, omega-3 fatty acid supplementation, or hypolipemiant treatment. Herbal medicine has been used in the human clinical routine to reduce cholesterol circulation. With an aim to expand its application in veterinary medicine, we analyzed the use of phytosterols in dogs as a potential alternative to control hypercholesterolemia. We performed lipidogram analysis in healthy dogs to examine the possible adverse effects during the treatment. Eight Beagle dogs received orally two 650 mg capsules of phytosterols (Collestra, Aché), for 15 consecutive d, along with the 2 usual meals. All animals remained clinically stable during the trial. There were significant alterations in low-density lipoprotein (LDL) and high-density lipoprotein (HDL) levels during the trial. LDL was reduced (86.8 ± 29.89 mg/dL [D0], 74.45 ± 31.58 mg/dL [D8], and 58.91 ± 18.65 mg/dL [D15]; P = 0.0442) and HDL was elevated (83.40 ± 12.05 mg/dL [D0], 86.46 ± 13.05 mg/dL [D8], and 101.5 ± 10.52 [D15]; P = 0.0141), while total cholesterol and triglyceride concentrations remained constant and within the normal range for canine species. Thus, a 1300 mg dose of phytosterols, administrated orally and fractionated along with the 2 usual meals, was capable of reducing LDL and increasing HDL concentration in healthy nondyslipidemic dogs, which makes them candidates to be included on the list of hypolipemiant drugs for clinical use in dogs with hypercholesterolemia.

Comparison of cholesterol levels among lipoprotein fractions separated by anion-exchange high-performance liquid chromatography in periparturient Holstein-Friesian dairy cows

Changes in lipoprotein profiles occur in dairy cows during the periparturient period and in cows with transition cow disease. Here, the lipoprotein profiles of Holstein–Friesian dairy cows during the periparturient period were obtained by anion-exchange, high-performance liquid chromatography to evaluate the usefulness of lipoprotein profile evaluation during the periparturient period and in cows with fatty liver and milk fever. Lipoprotein levels (including total and high- (HDL-C) and low-density lipoprotein (LDL-C) cholesterol) in 10 healthy cows were low 4 weeks prepartum, with the lowest values at calving or within 1 week of calving; the values increased at 8 weeks postpartum. The lipoprotein levels were measured in 16 cows diagnosed with fatty liver (n=10) or milk fever (n=6) and compared to 10 healthy dairy cows. A significant difference was observed in HDL-C between healthy cows (at calving and 1 week postpartum), and the fatty liver and milk fever cows. Cows with fatty liver and milk fever had a lower mean HDL-C than the 10 healthy dairy cows at calving and 1 week postpartum. HDL-C might be a good indicator of energy balance for differentiating healthy cows from those with transition cow disease.

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.