L Advanced Drug Delivery Reviews 30 (1998) 85–95 Gene transfer with lipospermines and polyethylenimines a, b a a * Jean-Serge Remy , Bassima Abdallah , Maria Antonietta Zanta , Otmane Boussif , Jean- a b Paul Behr , Barbara Demeneix a ´´ ´ ´ Laboratoire de Chimie Genetique, URA 1386, Faculte de Pharmacie, Universite Louis Pasteur, Strasbourg, France b ´´ ´ Laboratoire de Physiologie Generale et Comparee, U.R. A.90 CNRS, Museum National d’ Histoire Naturelle, F-75231, Paris Cedex 5, France Received 1 November 1996; accepted 11 February 1997 Abstract It is an obvious and basic principle that to be efficient, gene therapy requires effective gene transfer followed by adequate gene expression. However, getting DNA, a pro-drug, into the cell and into the nucleus, remains a crucially limiting factor. Even recombinant viral methods still show poor performances in clinical situations and non-viral methods are considered classically to be of yet lower efficiency. Here, we consider the mode of action, the nature of the complexes formed with DNA and the transfection potentials of two categories of inert, cationic vectors, the lipospermines and polyethylenimine. Both are among the best vectors currently available for in vitro work. Moreover, polyethylenimine is proving to be a versatile and effective carrier for different in vivo situations, especially for delivering genes into the mammalian brain.  1998 Elsevier Science B.V. Keywords: Cationic lipids; Transfectam; Exgen 500; In vivo gene transfer; In vitro gene delivery; Mammalian brain; Cationic polymers Contents 1. Introduction ............................................................................................................................................................................ 86 1.1. Gene therapy’s bottle neck is gene transfer ........................................................................................................................ 86 2. Lipospermines and polyethylenimines — concepts and structural features ................................................................................... 86 3. Results in cell lines and primary culture .................................................................................................................................... 88 3.1. Centrifugation and condensing DNA in small volumes improve efficiency, especially when serum is present during transfection ...................................................................................................................................................................... 88 3.2. PEI is versatile and provides high levels of gene expression in vitro .................................................................................... 88 4. In vivo gene transfer mediated by Transfectam and polyethylenimines ........................................................................................ 89 4.1. Low charge ratios and the addition of dioleoylphosphatidyl ethanolamine (DOPE) can be used for in vivo Transfectam- mediated gene transfer ...................................................................................................................................................... 89 4.2. In vivo veritas: PEI can be used in different in vivo situations ............................................................................................. 92 5. Conclusion and perspectives .................................................................................................................................................... 93 Acknowledgements ...................................................................................................................................................................... 94 References .................................................................................................................................................................................. 94 * Corresponding author. 0169-409X / 98 / $19.00  1998 Elsevier Science B.V. All rights reserved. PII S0169-409X(97)00109-9