Change search
ReferencesLink to record
Permanent link

Direct link
Lipoprotein lipase during continuous heparin infusion: Tissue stores become partially depleted
Umeå University, Faculty of Medicine, Department of Medical Biosciences.
Umeå University, Faculty of Medicine, Department of Medical Biosciences.
Umeå University, Faculty of Medicine, Department of Medical Biosciences.
Umeå University, Faculty of Medicine, Department of Medical Biosciences.
2001 (English)In: Journal of Laboratory and Clinical Medicine, ISSN 0022-2143, E-ISSN 1532-6543, Vol. 138, no 3, 206-213 p.Article in journal (Refereed) Published
Abstract [en]

Lipoprotein lipase (LPL) and hepatic lipase (HL) are located at vascular surfaces in extrahepatic tissues and in the liver, respectively. Heparin displaces the enzymes into the circulating blood. Animal studies have shown that the liver takes up and degrades LPL. To explore whether heparin leads to a depletion of tissue stores, we followed the lipase activities in plasma during an 8-hour primed infusion of heparin in 10 healthy subjects. After an initial peak, the HL activity decreased slowly after a time curve similar to that for activated partial thromboplastin time. The time curve for LPL was different. After the initial peak, the activity dropped by almost 80%, from 30 to 120 minutes, and then leveled off to a plateau that corresponded to about 15% of the peak level. A second bolus of heparin was given to 4 subjects after 4 hours. The plasma LPL activity increased, but only to about 35% of the original peak level. We conclude that when heparin releases LPL into plasma, the lipase becomes liable to be taken up and degraded by the liver. After less than 1 hour, the stores of LPL have been exhausted, and recruitment of lipase into plasma depends on a slow but stable delivery of newly synthesized molecules.

Place, publisher, year, edition, pages
2001. Vol. 138, no 3, 206-213 p.
National Category
Medical and Health Sciences
URN: urn:nbn:se:umu:diva-4168DOI: 10.1067/mlc.2001.117666PubMedID: 11528374OAI: diva2:143156
Available from: 2004-10-27 Created: 2004-10-27 Last updated: 2010-08-11Bibliographically approved
In thesis
1. Lipoprotein lipase in hemodialysis patients and healthy controls: effects of heparin
Open this publication in new window or tab >>Lipoprotein lipase in hemodialysis patients and healthy controls: effects of heparin
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Mortality from cardiovascular disease in patients on chronic hemodialysis (HD) is 10 to 20 times greater than in the general population. One major risk factor is renal dyslipidemia, characterised by an impaired catabolism of triglyceride (TG)-rich lipoproteins with accumulation of atherogenic remnant particles. A contributing factor may be derangement of the lipoprotein lipase (LPL) system, the major lipase in the catabolism of TG-rich lipoproteins. The functional pool of LPL is located at vascular surfaces, and is released by heparin into the circulating blood and extracted and degraded by the liver. Unfractionated heparin (UFH) is commonly used during dialysis to avoid clotting in the extracorporeal devices, but is increasingly replaced by various low molecular weight heparin (LMWH) preparations. Plasma LPL activity is usually lower after injection of LMWH which is therefore said to release less LPL and cause less disturbance of lipoprotein metabolism than UFH. However, animal studies have revealed that LMWH is as efficient as UFH in releasing LPL but is less efficient in retarding hepatic uptake. The aim of this study was to explore the effects of UFH and a LMWH (dalteparin) on LPL activity and TG concentrations in HD-patients compared with healthy controls, matched for age and gender. A disturbed LPL system might contribute to an impaired lipoprotein metabolism, and hence, an aggravated cardiovascular condition.

An 8-hour primed infusion of UFH to controls gave rise to an initial peak of LPL activity within 30 minutes. The activity then dropped by almost 80% over the next two hours and levelled off to a plateau that corresponded to 15% of the peak level. When UFH was infused to HD-patients the curve for LPL activity resembled that for controls, but was reduced by 50% during the peak, while the plateau activities were comparable. The interpretation was that the functional pool, represented by the initial peak, was impaired in HD-patients, while the production of lipase molecules, reflected by the plateau, was only marginally reduced. During the peak of LPL activity TG decreased in both groups, but less in HD-patients, as was expected from the lower circulating lipase activity. During the plateau phase with low lipase activity, TG increased towards and beyond baseline values.

When dalteparin was infused, the same pattern of plasma LPL activity was observed, although remarkably reduced. In controls the peak was only 30% and the subsequent plateau 40% compared with the activities during the UFH infusion. A bolus of UFH given when the LPL activity had levelled off to a plateau brought out about the same amount of activity, regardless of whether dalteparin or UFH had been infused. The conclusion was that both heparin preparations had reduced endothelial LPL to a similar extent, but that dalteparin less efficiently retarded the hepatic uptake of the enzyme. As a consequence to this, TG tended to reach higher levels after the dalteparin infusion. The LPL activities were further reduced in HD-patients during infusion with dalteparin, the peak was only 27% and the plateau 35% compared with the activities when UFH was infused. There was no decrease in TG, but rather a continuous increase, suggesting a profound depletion of functional LPL.

In another study in HD-patients, two anticoagulation regimes based on present clinical practice were compared, and the doses were adjusted to the respective manufacturers recommendation. UFH was administered as a primed infusion, whereas dalteparin was given only as a single bolus pre-dialysis, not followed by an infusion. The results were in line with those in the experimental studies and indicate that also in the clinical setting LMWH interferes with the LPL system as least as much as an infusion of UFH does, and temporarily impairs lipolysis of TG. This interference might, in consequence, contribute to an aggravated cardiovascular condition in HD-patients.

65 p.
Umeå University medical dissertations, ISSN 0346-6612 ; 921
dalteparin, dialysis, lipoprotein metabolism, LMWH, LPL, triglycerides, UFH, uremia
Research subject
Medical and Physiological Chemistry
urn:nbn:se:umu:diva-340 (URN)91-7305-742-8 (ISBN)
Public defence
2004-11-12, E04, 6E, 13:00
Available from: 2004-10-27 Created: 2004-10-27 Last updated: 2010-08-11Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Olivecrona, GunillaOlivecrona, ThomasStegmayr, Bernd G.
By organisation
Department of Medical Biosciences
In the same journal
Journal of Laboratory and Clinical Medicine
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 35 hits
ReferencesLink to record
Permanent link

Direct link