Species differences in lipoprotein lipase and hepatic lipase activities: comparative studies of animal models of lifestyle-related diseases

Abstract

Lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) have an important role in lifestyle-related diseases. To evaluate species differences, we compared LPL and HTGL activities in different animal models of lifestyle-related diseases using the same assay kit. Normal animals (JW rabbits, ICR mice, and SD rats), a hypercholesterolemic animal model (WHHLMI rabbits), and obese animal models (KK- A y mice and Zucker fatty rats) fed standard chow were used in this study. Plasma was prepared before and after an intravenous injection of heparin sodium under fasting and feeding. LPL and HTGL activities were measured with the LPL/HTGL activity assay kit (Immuno-Biological Laboratories) using an auto-analyzer. Only in mice, high HTGL activity was observed in pre-heparin plasma. In normal animals, LPL and HTGL activities were high in ICR mice and SD rats but low in JW rabbits. Compared to normal animals, LPL activity was high in Zucker fatty rats and WHHLMI rabbits at both fasting and feeding, while LPL activity after feeding was low in KK- A y mice. HTGL activity was higher in fasted and fed WHHLMI rabbits and fasted Zucker fatty rats, but was lower in fed KK- A y mice. Gender difference was observed in HTGL activity in SD rats and LPL activity in WHHLMI rabbits but not in ICR mice. In conclusion, this simple assay method was effective for measuring LPL and HTGL activities of experimental animals, and the activities are highly regulated depending on animal species, animal models, feeding/fasting conditions and genders.

The 1,2‐o‐dilauryl‐rac‐glycero‐3‐glutaric acid‐(6’‐methylresorufin) ester (DGGR) lipase assay in cats and dogs is not specific for pancreatic lipase

“…For example, with food intake, plasma triglyceride concentrations increase, causing release and activation of circulating hepatic and lipoprotein lipases 23,40 to hydrolyze lipoprotein triglycerides. Circulating hepatic and lipoprotein lipases also differ by species 24 . This could be why, in our study, cats had more pronounced increases than dogs in plasma lipase activities after heparin injection.…”

“…This could be why, in our study, cats had more pronounced increases than dogs in plasma lipase activities after heparin injection. Additionally, body condition plays a role; obese animals have higher circulating lipoprotein lipase levels than lean animals 24 . Sex hormones can also affect lipase levels, as circulating hepatic lipase levels have been shown to be higher in men than in premenopausal but not postmenopausal women 21,41 .…”

“…While hepatic lipase is synthesized exclusively in the liver, where it is predominantly found, lipoprotein lipase is synthesized primarily in adipose tissue and muscle and is anchored to capillary endothelial cells 21,22 . Intravenous heparin injection is well‐known to cause the release of hepatic and lipoprotein lipase into circulation 23,24 . In people, plasma lipase activity measurements after heparin injection are used commonly to investigate dyslipidemia 25,26 .…”

The History of the WHHL Rabbit, an Animal Model of Familial Hypercholesterolemia (II) - Contribution to the Development and Validation of the Therapeutics for Hypercholesterolemia and Atherosclerosis -

“…In apoE-KO mice, the VLDL fraction is increased markedly, but the VLDL particles contain apoB-48 instead of apoB-100 92) . In addition, no cholesterol ester-transfer protein activity in the plasma 93) , high activity of hepatic LDL receptor function 86) , and high activity of hepatic lipase in pre-heparin plasma 94) in mice are also very different from humans. However, those of rabbits are close to humans [85][86][87][88] .…”

Endothelial Lipase Exerts its Anti-Atherogenic Effect through Increased Catabolism of β-VLDLs

“…Lipoprotein lipase (LPL) activity in post-heparinized plasma was measured using the method described previously 24,25) . Briefly, blood was withdrawn from rabbits after heparin injection, and LPL activity in the post-heparin plasma was analyzed through an automated colorimetric method using the natural long-chain fatty acid 2-diglyceride as a substrate (Immuno-Biological Laboratories Co., Ltd., Gunma, Japan).…”