HDL particle concentration

This biomarker describes the amount of HDL particles in the bloodstream. HDL particles transport cholesterol from tissues to the liver. Disorders affecting HDL cholesterol typically affect HDL particle concentration, too. However, some disorders increasing HDL cholesterol do not significantly change HDL particle concentration, but increase in HDL particle size by increasing the cholesterol concentration of HDL particles. However, factors affecting HDL particle concentration have not been extensively studied in dogs.

 

Decreased concentrations

– Pancreatic insufficiency
– Obesity
– Biliary obstruction

 

Total lipids in HDL particles

This biomarker represents the total amount of lipids transported in HDL particles. Because cholesterol is the most abundant lipid in HDL particles, the total lipid content of HDL particles changes mainly in disorders affecting HDL cholesterol. The increase in the total lipid content of HDL particles is associated with either an increase in the number of HDL particles or an increase in HDL particle size. Examining changes in the total lipid content, composition, particle concentration, and size of HDL particles offers unmatched precision in evaluating changes in HDL metabolism.

 

HDL particle diameter

This biomarker describes the average size of HDL lipoprotein particles. Changes in lipoprotein metabolism can also alter the size of lipoprotein particles. In dogs, conditions such as diabetes, hypothyroidism, idiopathic hypercholesterolemia, and high fat diet, increase the number of large cholesterol-rich HDL particles. In humans, however, these conditions cause cholesterol to be transferred to VLDL and LDL particles, which is suspected to be a major factor explaining why humans have a higher predisposition to atherosclerosis than dogs. However, factors affecting HDL particle diameter have not been extensively studied in dogs.

 

Additional information

Xenoulis, P. G. & Steiner, J. M. Lipid metabolism and hyperlipidemia in dogs. Vet. J. 183, 12–21 (2010).
Xenoulis, P. G. & Steiner, J. M. Canine hyperlipidaemia. J. Small Anim. Pract. 56, 595–605 (2015).

Thrall, M. A., Weiser, G., Allison, R. W. & Campbell, T. W. Veterinary Hematology and Clinical Chemistry. (Wiley-Blackwell, 2012).
Danielsson, B., Ekman, R., Johansson, B. G. & Petersson, B. G. Plasma lipoprotein changes in experimental cholestasis in the dog. Clin. Chim. Acta. 80, 157–170 (1977).
Chikamune, T., Katamoto, H., Ohashi, F. & Shimada, Y. Serum lipid and lipoprotein concentrations in obese dogs. J. Vet. Med. Sci. 57, 595–598 (1995).
Minamoto, T. et al. Evaluation of density gradient ultracentrifugation serum lipoprotein profiles in healthy dogs and dogs with exocrine pancreatic insufficiency. J. Vet. Diagn. Invest. 30, 878–886 (2018).

 

LDL particle concentration

LDL is formed from VLDL when triglycerides have been transferred from VLDL into tissues. LDL is rich in cholesterol and is responsible for transporting cholesterol to tissues. LDL particle concentration typically changes in conditions causing hypercholesterolemia and especially elevated LDL cholesterol.

 Increased concentrations

– Diabetes mellitus
– Hypothyroidism
– Cushing’s disease
– Pancreatitis
– Renal failure
– Nephrotic syndrome
– Biliary obstruction
– Obesity

 

Total lipids in LDL particles

This biomarker describes the total amount of lipids transported in the LDL particles. The function of LDL particles is to transport cholesterol to tissues. Because the main lipid in LDL particles is cholesterol, hypercholesterolemic disorders that affect LDL cholesterol typically result in an increase in the total lipid content of LDL particles. Examining changes in the total lipid content, composition, particle concentration, and size of LDL particles offers unmatched precision in evaluating changes in LDL metabolism.

 

LDL particle diameter

This biomarker reflects the average size of LDL particles. Changes in lipoprotein metabolism can also alter the size of lipoprotein particles. In humans, the number of small, dense LDL particles increases in certain hypercholesterolemic diseases. Dogs also appear to have a similar tendency, since hypercholesterolemia is associated with reduced LDL particle size. Hypocholesterolemia also reduces LDL particle size. However, factors affecting LDL particle diameter have not been extensively studied in dogs.

 

Additional information

Xenoulis, P. G. & Steiner, J. M. Lipid metabolism and hyperlipidemia in dogs. Vet. J. 183, 12–21 (2010).
Xenoulis, P. G. & Steiner, J. M. Canine hyperlipidaemia. J. Small Anim. Pract. 56, 595–605 (2015).
Thrall, M. A., Weiser, G., Allison, R. W. & Campbell, T. W. Veterinary Hematology and Clinical Chemistry. (Wiley-Blackwell, 2012).
Whitney, M. S., Boon, G. D., Rebar, A. H., Story, J. A. & Bottoms, G. D. Ultracentrifugal and electrophoretic characteristics of the plasma lipoproteins of miniature schnauzer dogs with idiopathic hyperlipoproteinemia. J. Vet. Intern. Med. 7, 253–260 (1993).
Chikamune, T., Katamoto, H., Ohashi, F. & Shimada, Y. Serum lipid and lipoprotein concentrations in obese dogs. J. Vet. Med. Sci. 57, 595–598 (1995).
Minamoto, T. et al. Evaluation of density gradient ultracentrifugation serum lipoprotein profiles in healthy dogs and dogs with exocrine pancreatic insufficiency. J. Vet. Diagn. Invest. 30, 878–886 (2018).
Rogers, W. A., Donovan, E. F. & Kociba, G. J. Lipids and lipoproteins in normal dogs and in dogs with secondary hyperlipoproteinemia. J. Am. Vet. Med. Assoc. 166, 1092–1100 (1975).
Behling-Kelly, E. Serum lipoprotein changes in dogs with renal disease. J. Vet. Intern. Med. 28, 1692–1698 (2014).

 

VLDL particle concentration

This biomarker represents the total concentration of chylomicrons and VLDL particles in the sample. Chylomicrons are responsible for transporting triglycerides from the small intestine to other tissues after eating. VLDL particles, in turn, are formed by the liver and carry triglycerides for use in muscle and fat tissue. VLDL particles are formed in the liver when more fatty acids are provided in the diet than are immediately needed for energy production. VLDL concentration can be affected, for example, by diet and certain diseases.

 

Increased concentrations

– Diabetes mellitus
– Hypothyroidism
– Cushing’s disease
– Pancreatitis
– Idiopathic hyperlipidemia
– Renal failure
– Nephrotic syndrome
– Obesity

Decreased concentrations

– Pancreatic insufficiency

 

Total lipids in VLDL particles

This biomarker represents the amount of lipids transported in VLDL particles and chylomicrons. VLDL particles transport triglycerides to tissues. Triglycerides are the main lipid in VLDL particles. Thus, in hypertriglyceridemic conditions, the total lipid content of VLDL particles will also typically increase. Increased VLDL lipids can be associated with increased particle size, increased particle concentration, or both. Examining changes in the total lipid content, composition, particle concentration, and size of VLDL particles offers unmatched precision in evaluating changes in VLDL and chylomicron metabolism.

 

VLDL particle diameter

This biomarker represents the combined average diameter of VLDL particles and chylomicrons. The diameter of chylomicrons is considerably larger than the diameter of VLDL particles. Thus, an increase in this value may be caused by an increased relative concentration of chylomicrons, increased chylomicron size, or increased VLDL particle size. The number of chylomicrons in the bloodstream rises after eating, so in non-fasted dogs this value may be higher than normal. The diameter of the VLDL particles can also be increased in e.g. diabetes. However, factors affecting VLDL particle diameter have not been extensively studied in dogs.

 

Additional information

Xenoulis, P. G. & Steiner, J. M. Lipid metabolism and hyperlipidemia in dogs. Vet. J. 183, 12–21 (2010).
Xenoulis, P. G. & Steiner, J. M. Canine hyperlipidaemia. J. Small Anim. Pract. 56, 595–605 (2015).
Thrall, M. A., Weiser, G., Allison, R. W. & Campbell, T. W. Veterinary Hematology and Clinical Chemistry. (Wiley-Blackwell, 2012).
Whitney, M. S., Boon, G. D., Rebar, A. H., Story, J. A. & Bottoms, G. D. Ultracentrifugal and electrophoretic characteristics of the plasma lipoproteins of miniature schnauzer dogs with idiopathic hyperlipoproteinemia. J. Vet. Intern. Med. 7, 253–260 (1993).
Chikamune, T., Katamoto, H., Ohashi, F. & Shimada, Y. Serum lipid and lipoprotein concentrations in obese dogs. J. Vet. Med. Sci. 57, 595–598 (1995).
Minamoto, T. et al. Evaluation of density gradient ultracentrifugation serum lipoprotein profiles in healthy dogs and dogs with exocrine pancreatic insufficiency. J. Vet. Diagn. Invest. 30, 878–886 (2018).
Rogers, W. A., Donovan, E. F. & Kociba, G. J. Lipids and lipoproteins in normal dogs and in dogs with secondary hyperlipoproteinemia. J. Am. Vet. Med. Assoc. 166, 1092–1100 (1975).
Behling-Kelly, E. Serum lipoprotein changes in dogs with renal disease. J. Vet. Intern. Med. 28, 1692–1698 (2014).