Development of a procedure for coupling the homing device glu-plasminogen to liposomes

Heeremans, J.L.M.; Kraaijenga, J. J.; Los, P.; Kluft, C.; Crommelin, Daan J.A.

doi:10.1016/0304-4165(92)90022-m

Cited by 29 publications

(10 citation statements)

References 26 publications

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“…Liposomes were prepared according to Heeremans et al (1992) and Mastrobattista et al (1999) with some modifications. Briefly, liposomes were prepared of EPC-35 and cholesterol in a 2:1 molar ratio, with 2.5% PEG 2000 -DSPE and 2.5% PEG 2000 -maleimide-DSPE.…”

Section: Liposome Preparationmentioning

confidence: 99%

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Coupling of Metal Containing Homing Devices to Liposomes via a Maleimide Linker: Use of TCEP to Stabilize Thiol-groups without Scavenging Metals

Visser¹,

Voorwinden²,

Harders³

et al. 2004

Journal of Drug Targeting

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Liposomes for drug delivery are often prepared with maleimide groups on the distal end of PEG to enable coupling of homing devices, such as antibodies, or other proteins. EDTA is used to stabilize the thiol group in the homing device for attachment to the maleimide. However, when using a homing device that contains a metal, EDTA inactivates this by scavenging of the metal. Holo-transferrin (Tf) containing two iron atoms (Fe(3+)), has a much higher affinity for the Tf receptor than apo-Tf (which does not contain any Fe(3+)). To couple Tf to a liposome, the introduction of a thiol group is necessary. During this process, by using N-succinimidyl S-acetylthioacetate (SATA), followed by 2-3 h coupling to the liposomes, Fe(3+) is scavenged by EDTA. This causes a decreased affinity of Tf for its receptor, resulting in a decreased targeting efficiency of the liposomes. Tris(2-carboxyethyl)phosphine (TCEP) hydrochloride is a sulfhydryl reductant that is often used in protein biochemistry. We found that TCEP (0.01 mM) does not scavenge Fe(3+) from Tf and is able to protect thiol groups for the coupling to maleimide. Furthermore, TCEP does not interfere with the maleimide coupling itself. In this communication, we describe the preparation of liposomes, focussing on the coupling of Tf to the maleimide linker at the distal end of PEG, without loosing Fe(3+) from Tf. This method can be applied to other metal-containing homing devices as well.

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Section: Liposome Preparationmentioning

confidence: 99%

“…For the preparation of liposomes we have adapted the method used by Heeremans et al (1992) and Mastrobattista et al (1999) who have used maleimide to couple a homing device to liposomes. Certain homing devices such as Fab-fragments contain a thiol group for coupling to maleimide.…”

Section: Introductionmentioning

confidence: 99%

Coupling of Metal Containing Homing Devices to Liposomes via a Maleimide Linker: Use of TCEP to Stabilize Thiol-groups without Scavenging Metals

Visser¹,

Voorwinden²,

Harders³

et al. 2004

Journal of Drug Targeting

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“…N-[4-(p-Maleimidophenyl) butyryl]phosphatidylethanolamine (MPB-PE) was synthesized, purified and analyzed as described before [28,29]. MPB-PE was incorporated into the liposomal bilayers to allow covalent coupling of thiol containing proteins to the liposomal surface [30][31][32][33]. The lipid composition of the liposomes used was PHEPC/EPG/ CHOL/MPB-PE/rhodamine-PE at a molar ratio of 10/1/4/0.4/0.01.…”

Section: Preparation Of Immunoliposomesmentioning

confidence: 99%

Adhesion molecules: a new target for immunoliposome‐mediated drug delivery

et al. 1995

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The anti-ICAM-1 monoclonal antibody FI0.2 was conjugated to liposomes to target to cells expressing the cell adhesion molecule ICAM-1. We demonstrate that F10.2 immunoliposomes bind to human bronchial epithelial cells (BEAS-2B) and human umbilical vein endothelial cells (HUVEC) in a specific, dose-and time-dependent manner. It appears that the degree of ICAM-I expression is the limiting factor in the degree of immunoliposome binding to the cells. These results are a first step in the strategy for specific drug delivery to target sites characterised by increased expression of adhesion molecules.

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“…Concerning the first technology, we developed a covalent binding procedure for plasminogen to the surface of liposomes (13). It was possible to introduce various densities of plasminogen on the liposomes and the in vitro binding to fibrin was found to be significantly increased (11,13).…”

Section: Acute Myocardial Infarction Is One Of the Main Causes Of Deamentioning

confidence: 99%

Thrombolytic Treatment with Tissue-type Plasminogen Activator (t-PA) Containing Liposomes in Rabbits: a Comparison with Free t-PA

Heeremans

Prevost

Bekkers³

et al. 1995

Thromb Haemost

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SummaryIn this study, we aimed at improving the therapeutic index of tissue- type Plasminogen Activator (t-PA) as thrombolytic agent in the treatment of myocardial infarction. Liposome-encapsulated t-PA was tested in a rabbit jugular vein thrombosis model: administration of free t-PA (t-PA) as a bolus injection in the ear vein was compared to a similar administration of liposomal t-PA (t-PA-lip), liposomal t-PA in plasminogen-coated liposomes (Plg-t-PA-lip), a mixture of free t-PA and empty liposomes (t-PA+empty lip) and a saline-blank (blank) in terms of thrombolytic activity and side effects.Liposomal t-PA (t-PA-lip/Plg-t-PA-lip) showed a significantly better thrombolysis efficiency than equimolar doses of free t-PA (t-PA/ t-PA+ empty lip): about 0.24 mg/kg of liposomal t-PA practically equalled the lysis-activity of a dose of free t-PA of 1.0 mg/kg (t-PAlmg/kg). On the other hand, liposome encapsulation did not affect the systemic activation of alpha2-antiplasmin and plasminogen by t-PA.We conclude that for this model an improvement in thrombolytic efficacy of t-PA is achieved by liposome encapsulation of t-PA. As t-PA-lip and Plg-t-PA-lip -treatment induced similar results, targeting of liposomal t-PA by coupled glu-Plg remains a topic to be optimized in future studies.

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Development of a procedure for coupling the homing device glu-plasminogen to liposomes

Cited by 29 publications

References 26 publications

Coupling of Metal Containing Homing Devices to Liposomes via a Maleimide Linker: Use of TCEP to Stabilize Thiol-groups without Scavenging Metals

Coupling of Metal Containing Homing Devices to Liposomes via a Maleimide Linker: Use of TCEP to Stabilize Thiol-groups without Scavenging Metals

Adhesion molecules: a new target for immunoliposome‐mediated drug delivery

Thrombolytic Treatment with Tissue-type Plasminogen Activator (t-PA) Containing Liposomes in Rabbits: a Comparison with Free t-PA

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