Rj. Mumper et al., POLYVINYL DERIVATIVES AS NOVEL INTERACTIVE POLYMERS FOR CONTROLLED GENE DELIVERY TO MUSCLE, Pharmaceutical research, 13(5), 1996, pp. 701-709
Purpose. DNA plasmids (pDNA) can be taken up by and expressed in stria
ted muscle after direct intramuscular injection. We have developed int
eractive polymeric gene delivery systems that increase pDNA bioavailab
ility to muscle cells by both protecting pDNA from nucleases and contr
olling the dispersion and retention of pDNA in muscle tissue. Methods.
A DNA plasmid, containing a CMV promoter and a beta-galactosidase rep
orter gene (CMV-beta-gal), was injected either in saline or formulated
in polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) solutions.
Interactions between PVP and pDNA were assessed by dynamic dialysis,
Isothermal Titration Calorimetry (ITC), and Fourier-Transformed Infra
Red (FT-IR) spectroscopy. Formulations (50 mu l) were injected into ra
t tibialis muscles after surgical exposure. Immunohistochemistry for b
eta-gal was used to visualize the sites of expression in muscle. Resul
ts. beta-gal expression using pDNA in saline reached a plateau while b
eta-gal expression using PVP formulations increased linearly in the do
se range studied (12.5-150 mu g pDNA injected) and resulted in an incr
ease in the number and distribution of cells expressing beta-gal. The
interaction between PVP and pDNA was found to be an endothermic proces
s governed largely by hydrogen-bonding and results in protection of pD
NA from extracellular nucleases. Conclusions. Significant enhancement
of gene expression using interactive polyvinyl-based delivery systems
has been observed. The improved tissue dispersion and cellular uptake
of pDNA using polyvinyl-based systems after direct injection into musc
le is possibly due to osmotic effects.