Targeting of Drugs Anatomical and Physiological Considerations Edited by Gregory Gregoriadis Royal Free Hospital School of Medicine London, United Kingdom and George Poste Smith Kline & French Laboratories Philadelphia, Pennsylvania Plenum Press New York and London Published in cooperation with NATO Scientific Affairs Division Proceedings of a NATO Advanced Study Institute on Targeting of Drugs: Anatomical and Physiological Considerations, held June 20-July 1, 1987, In Cape Sounlon Beach, Greece ISBN-13: 978-1-4684-5576-2 e-ISBN-13: 978-1-4684-5574-8 001: 10.1007/978-1-4684-5574-8 © 1988 Plenum Press, New York Softcover reprint of the hardcover 1s t edition 1988 A Division of Plenum Publishing Corporation 233 Spring Street, New York, N.Y. 10013 All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher PREFACE A major vehicle for the transition of carrier-mediated drug delivery from a theoretical/experimental status to one with practical uses has been the NATO Advanced Studies Institute series "Targeting of Drugs". Three previous ASls of the series[1-3], also held in Cape Sounion, dealt with carriers of natural and synthetic origin, their preparation and drug incorporation as well as a wide range of applications. This book contains the proceedings of the 4th NATO ASI "Targeting of Drugs: Anatomical and Physiological Considerations" held in Cape Sounion, Greece during 20 June - 1 July 1987. Historically, carrier systems have been chosen on the basis of selective affinity for target sites. For instance, monoclonal antibodies bind selectively to antigens on the surface of cells and the same applies to ligands such as certain glycoproteins which bind to cell receptors. Colloidal carriers on the other hand, are "passively" targeted to the reticuloendothelial system. However, effective drug delivery depends not only on demonstration of affinity of the carrier system for its target but also, and perhaps crucially, on the way(s) by which the carrier-drug entity interacts with the interposed biological milieu. The book deals in depth with a number of biological milieus as travelled space for carriers en route to their destination, difficulties arising from unfavorable milieu-carrier interactions and ways to circumvent such difficulties. It also identifies, when possible, situations where proposed uses would or would not be realistic and provides perspectives for future goals. We express our appreciation to Dr A.C. Allison, Professor S.S. Davis, and Professor K. Sikora for their valuable advice throughout the planning stages of the ASI and to Dr G. Deliconstantinos who, as chairman of the local committee, contributed most effectively to its success. We are also grateful to Mrs A. Massaro for both the enthusiastic management of many of the practical aspects of the Institute and editorial help. The ASI was held under the sponsorship of NATO Scientific Affairs Division and co sponsored and generously financed by Smith Kline and French Laboratories, Philadelphia, USA. Financial assistance was also provided by Schering (FRG), Ciba Geigy (UK), Hoffmann La Roche (Switzerland), Boeringer (FRG), Armour (USA), Biophor (USA), Syntex (USA), Biogen (USA), Avanti (USA), Pfizer (UK), and ICI (UK). May 1988 Gregory Gregoriadis George Poste v 1. Targeting of Drugs (eds. Gregoriadis. G• • Senior. J. and Trouet. A.). Plenum. 1982. 2. Receptor-Mediated Targeting of Drugs (eds. Gregoriadis. G• • Poste, G., Senior, J. and Trouet, A.), Plenum, 1984. 3. Targeting of Drugs with Synthetic Systems (eds. Gregoriadis, G., Senior. J. and Poste, G.), Plenum, 1986. CONTENTS The Structure of Different Types of Liver Cells in Relation to Uptake and Exchange Processes A. Geerts, L. Bouwens, R. de Zanger, H. van Bossuyt and E. Wisse 1 The Lymphatic System in Drug Targeting: An Overview J.G. Hall 15 The Hepatic Receptor for Asialoglycoproteins: Search for a Function C.J. Steer, P. Weiss, P.J. Wirth and G. Ashwell 29 The Galactose-Particle Receptor on Liver Macrophages: Biological Function and Implications for Clearance of Particulate Material V. Kolb-Bachofen 45 Free Radicals in Health and Disease: Implications for Drug Delivery and Targeting C. Rice-Evans 53 Monoclonal Antibodies and Drug Targeting in Cancer K. Sikora 69 Immunotoxins in Cancer Therapy F.K. Jansen, C. Blazy, H.E. Blythman, B. Bourrie, P. Carayon, P. Casellas, J.M. Derocq, D. Dussossoy, P. Gros, O. Gros, G. Laurent, G. Richer and H. Vidal 81 Techniques for Ex-Vivo Bone Marrow Treatment with Immunotoxins J.M. Derocq, G. Laurent, P. Casellas, H. Blythman and F.K. Jansen 93 The Potential of Memhrane-Actin8 Toxins for Targeted Cancer Therapy F.A. Drobniewski, P.E. Thorpe, P.M. Wallace and E.J. Wawrzynczak 103 In Vivo Uptake and Processing of Liposomes by Parenchymal and Non-parenchymal Liver Cells: Application to Immunotherapeutic Treatment of Hepatic Metastases G.L. Scherphof, T. Daemen, H. Derksen, G. Lazar, H.H. Spanjer and F.H. Roerdink 109 Platelet Activating Factor. a Potent Mediator of Allergy. as a Structural Component of Phosphatidylcholine Vesicles E. Skrika and C. Vakirtzi-Lemonias 121 Phospholipid Stereospecificity in Liposomal Modulation of Nitrogen Mustard Action C. Ritter. C. Prood and R.J. Rutman 137 Niosomes: A Putative Drug Carrier System A.J. Baillie 143 The Immunoadjuvant Action of Liposomes: Optimization Studies G. Gregoriadis. D. Davis and N. Garcon 153 Targeting of Antigens to Antigen-Presenting Cells and Their Activation: A Requirement for Vaccine Development A.C. Allison and N.E. Byars 167 Targeting Using Physical Approaches and Particulate Drug Carriers: Interaction with the Biological Milieu S.S. Davis and L. IlIum 177 Pragmatic Approaches to Delivery of Pep tides and Proteins as Drugs D.A. Eppstein 189 Reconstituted Influenza Virus Envelopes as a Potential Carrier for Fusion-Mediated Microinjection of Macromolecules into Living Cells A. Loyter and M. Lapidot 203 Contributors 213 Index 217 viii THE STRUCTURE OF DIFFERENT TYPES OF LIVER CELLS IN RELATION TO UPTAKE AND EXCHANGE PROCESSES Albert Geerts, Luc Bouwens, Ronald De Zanger, Hans Van Bossuyt and Eddie Wisse Laboratory for Cell Biology and Histology Free University Brussels (V.U.B.) 1090 Brussels-Jette, Belgium. INTRODUCTION The structural unit of the liver is classically named the liver lobule and is defined as a unit of parenchymal tissue characterized by peripheral branches of the portal vein and hepatic artery, and by a centrilobular branch of the hepatic vein, i.e. the central vein. The blood enters the lobule via the portal tracts through sinusoidal inlets and, after inter action with the parenchymal tissue during passage through the hepatic sinusoids, leaves the lobule through the central veins [Wisse and De Leeuw, 1984]. The alternative model of the liver acinus [Rappaport, 1973] puts the terminal portions of the portal tract in the middle and divides the paren chyma in zone I (periportal zone), zone II (midacinar zone) and the periph eral zone III. The peripheral tissue (zone III) of several adjacent acini forms a star shaped area around the terminal hepatic venules. A simple acinus contains at least two terminal branches of the hepatic vein at its periphery. This alternative model takes the existence of important gradi ents between zone I and zone III into account. The liver parenchyma is composed of several cell types including parenchymal and sinusoidal cells. The latter comprise endothelial, Kupffer, fat-storing and pit-cells [Wisse, 1977]. The parenchymal cells are not directly accessible for molecules or particles present in the sinusoidal blood. The sinusoidal endothelial cells form the sinusoidal lining which is interposed between the sinusoidal lumen and the underlying space of Disse. The hepatic sinusoidal endothelium is of a unique type. The endothelial cells possess numerous fenestrae or pores which lack a diaphragm. The fenestrae are organized in groups called sieve plates. Underneath the endothelial cells, fragments of basal lamina are present. Kupffer and pit cells are often present on or, less frequently, in between the sinusoidal endothelial cells. The space of Disse is a subendothelial tissue space, bordered on the luminal side by the endothelial lining and on the other side by the sinus oidal surface of the parenchymal cells bearing numerous microvilli. Behind the sinusoidal lining, in the space of Disse or in recesses between two adjacent parenchymal cells, the fat-storing cells (Ito cells, stellate cells, peri- or parasinusoidal cells, lipocytes) are found. In this paper, we will discuss the structural characteristics of the different liver cells in relation to the transport, exchange and uptake phenomena which take place in the hepatic sinusoids and in the underlying space of Disse. ENDOTHELIAL CELLS The Liver Sieve Sinusoidal endothelial cells form a continuous, but fenestrated lining of the hepatic sinusoids [Wisse, 1980J. Fig. 1 shows the endothelial lining of a rat liver sinusoid as seen in the scanning electron microscope. In rat liver, the fenestrae have an average diameter of 105 nm in the centrilobular areas of the liver and of III nm in periportal areas when measured on scanning electron micrographs after critical point drying of the tissue. The shrinkage of the tissue due to critical point drying is clearly shown by comparing the results obtained by scanning with the dia meter of fenestrae measured by transmission electron microscopy: 150 to 175 nm [Wisse et aI, 1985J. The fenestrae lack a diaphragm and are grouped together in so called sieve plates. In low pressure perfusion fixed liver, only fenestrae occur. Gaps, defined as endothelial pores with a diameter of at least twice the average diameter of the fenestrae, have been de scribed to occur inter- and intracellularly [Wisse et aI, 1985J. Most probably, these gaps form during the fixation procedure due to hypoxia or pressure exceeding the physiological pressure. The fenestrated endothelium filters chylomicrons and other particulate material, upon passage through the sinusoids [De Zanger and Wisse. 1982; Naito and Wisse, 1978; Wisse et aI, 1985J. In these studies, it has been shown that chylomicrons up to the size of fenestrae are present in the space of Disse whereas bigger ones are absent by apparent exclusion. The sieving of chylomicrons, their cholesterol rich remnants and other lipo proteins affects the rate of uptake of dietary fat from the circulation and therefore may play an important role in various diseases such as hyper lipidaemias and atherosclerosis [Fraser et aI, 1978; Fraser et al. 1986J. Possibly, this sieving effect is also of importance in the selective uptake by parenchymal cells of various particles injected in the systemic or portal bloodstream. Forced Sieving and Endothelial Massage It has been established by morphometry, that the size distributions of white and red blood cells overlap the size distributions of periportal, and to a lesser extent of pericentral sinusoids [Wisse et aI, 1985J. The mean diameters of red blood cells, white blood cells and sinusoids measured after critical point drying in the scanning electron microscope are re spectively 5.30 ~m, 4.90 ~m and 4.98 pm. This overlap implies that large blood cells are unable to pass through the sinusoids, unless the cells or the sinusoidal wall adapt their shape. By in vivo microscopy, it has been established that red blood cells are very flexible and adapt easily to the diameter of the hepatic sinusoids. White blood cells on the contrary, are more rigid and obstruct regularly the sinusoids [Wisse and McCuskey, 1986J From these observations, the concepts of "forced sieving" and "endothelial massage" have evolved [Wisse et aI, 1985]. Forced sieving is supposed to occur when fast-moving globular bodies such as red blood cells pass through the sinusoids. These bodies promote 2 Fig. 1. Scanning electron micrograph of the sinusoidal endothelium. Numerous fenestrae, organized in sieve plates, are present. In the space of Disse (SD), the microvilli of parenchymal cells are visible. the entrance of fluid or particles such as chylomicrons through the fen estrae into the space of Disse. Endothelial massage can occur when rigid white blood cells pass through narrow sinusoids. By compresssing the space of Disse, a downstream displacement of fluid present in the space of Disse would be induced. When fenestrae are encountered the fluid is forced out of the space of Disse into the sinusoid. When the white blood cell moves along, the microvilli of the parenchymal cells and the endothelial cell processes come back into position, and as a result new plasma will be sucked into the space of Disse. Endocytosis Blouin and coworkers [Blouin et aI, 1977] have demonstrated that, although sinusoidal endothelial cells represent only 2.8% of the paren chymal volume, they contain 45% of the pinocytotic vesicles and 14.5% of the lysosomes present in the hepatic parenchyma (Fig. 2). These obser vations indicate that endothelial cells take part in the uptake of com pounds from the sinusoidal blood. Indeed, endothelial cells take up var ious test substances when injected into the bloodstream [Praaning-Van Dalen et aI, 1981; Wisse, 1972]. Particulate material such as latex beads [Praaning-Van Dalen et aI, 1982a; Steffan et aI, 1986], colloidal sulfur, silver iodide and carbon [Praaning-Van Dalen et aI, 1982a], Thorotrast [Wisse, 1972], Frog-virus [Steffan et aI, 1981], heat aggregated albumin [Brouwer et aI, 1985], immune complexes [Van Der Laan-Klamer et aI, 1986], ferritins [Ghitescu and Fixman, 1984] and lipoproteins [Praaning-Van Dalen et aI, 1982b], as well as monodispersed molecules such as horseradish peroxidase [Praaning-Van Dalen et aI, 1982a] are taken up by these cells. By electron microscopy, two types of structures appear to mediate the uptake of particles by endothelial cells: bristle coated micropinocytotic 3 Fig. 2. Transmission electron micrograph of an endothelial cell. Numerous bristle coated micropinocytotic vesicles are present (arrows). In one of the cell processes, fenestrae (F) are ap parent. (L): lysosome. (C): centriole. Arrowheads: microtubules. SD: space of Disse. (P): parenchymal cell. vesicles and macropinocytotic vesicles [De Bruyn et aI, 1977; Wisse,· 1972]. According to the kinetics and other biochemical characteristics of the uptake, three mechanisms are distinguished: (i) fluid phase endocytosis, (ii) adsorptive, receptor mediated, endocytosis and (iii) adsorptive, non receptor mediated, endocytosis 125I-polyvinylpyrrolidone (PVP) is taken up by fluid phase endo cytosis, i.e. by pinocytosis without prior adsorption of the compound to the cell membrane [Praaning-Van Dalen et aI, 1981]. Several compounds are taken up through adsorptive, receptor mediated, endocytosis. One group of receptors is related to the hepatic catabolism of dietary fat: the remnant (apo E) receptor, the acetyl LDL (scavenger) receptor and the liver lipase receptor [Praaning-Van Dalen et aI, 1982b]. The scavenger receptor is present exclusively on endothelial cells and would remove all "old" (Le. chemically modified) LDL from serum [Nagelkerke et aI, 1984]. Endothelial cells also bear the Fe receptor [Van Der Laan-Klamer et aI, 1986]. It remains to be established, whether en dothelial cells remove significant quantities of immune complexes in vivo. Receptors for hyaluronic acid, chondroitin sulphate and collagen al (I) chain were demonstrated on isolated endothelial cells in primary culture [Smedsrod et aI, 1985a; Smedsrod et aI, 1985b; Smedsrod et aI, 1984]. If these receptors were operative in vivo, they might be of considerable importance in degrading excess connective tissue in the space of Disse. Mannose!N-acetylglucosamine terminated and galactose terminated glyco proteins are cleared from the blood by receptors present, through not exclusively, on endothelial cells. The physiological significance of these 4