ABSTRACT
Poly(amidoamine) (PAMAM) dendrimers are branched water-soluble polymers defined by consecutive generation numbers (Gn) indicating a parallel increase in size, molecular weight, and number of surface groups available for conjugation of bioactive agents. In this article, we compare the biodistribution of N-acetylgalactosamine (NAcGal)-targeted [(14) C]1 -G5-(NH2 )5 -(Ac)108 -(NAcGal)14 particles to non-targeted [(14) C]1 -G5-(NH2 )127 and PEGylated [(14) C]1 -G5-(NH2 )44 -(Ac)73 -(PEG)10 particles in a mouse hepatic cancer model. Results show that both NAcGal-targeted and non-targeted particles are rapidly cleared from the systemic circulation with high distribution to the liver. However, NAcGal-targeted particles exhibited 2.5-fold higher accumulation in tumor tissue compared to non-targeted ones. In comparison, PEGylated particles showed a 16-fold increase in plasma residence time and a 5-fold reduction in liver accumulation. These results motivated us to engineer new PEGylated G5 particles with PEG chains anchored to the G5 surface via acid-labile cis-aconityl linkages where the free PEG tips are functionalized with NAcGal or SP94 peptide to investigate their potential as targeting ligands for hepatic cancer cells as a function of sugar conformation (α versus ß), ligand concentration (100-4000 nM), and incubation time (2 and 24 hours) compared to fluorescently (Fl)-labeled and non-targeted G5-(Fl)6 -(NH2 )122 and G5-(Fl)6 -(Ac)107 -(cPEG)15 particles. Results show G5-(Fl)6 -(Ac)107 -(cPEG[NAcGalß ])14 particles achieve faster uptake and higher intracellular concentrations in HepG2 cancer cells compared to other G5 particles while escaping the non-specific adsorption of serum protein and phagocytosis by Kupffer cells, which make these particles the ideal carrier for selective drug delivery into hepatic cancer cells.
Subject(s)
Acetylgalactosamine/chemistry , Acetylglucosamine/analogs & derivatives , Dendrimers/chemistry , Peptides/chemistry , Polyethylene Glycols/chemistry , Acetylglucosamine/chemistry , Acetylglucosamine/pharmacokinetics , Acetylglucosamine/therapeutic use , Animals , Antigens, CD7/chemistry , Antigens, CD7/metabolism , Cells, Cultured , Dendrimers/pharmacokinetics , Dendrimers/therapeutic use , Fluorescent Dyes/chemistry , Half-Life , Hep G2 Cells , Humans , Kupffer Cells/cytology , Kupffer Cells/drug effects , Ligands , Liver/metabolism , Liver Neoplasms/drug therapy , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Mice , Mice, Nude , Particle Size , Peptides/metabolism , Phagocytosis , Polyethylene Glycols/pharmacokinetics , Polyethylene Glycols/therapeutic use , Rats , Time Factors , Tissue Distribution , Transplantation, HeterologousABSTRACT
Portable clinical analyzers are currently used in human and veterinary medicine for diagnostic testing and blood monitoring; however, normal values for mice and rats of varying genetic backgrounds have not previously been reported. Blood was collected from unanesthetized mice (n = 131) and rats (n = 76) into lithium heparin tubes for analysis using E6+ cartridges for the portable analyzer. Results of glucose, blood urea nitrogen (BUN), sodium, potassium, chloride, hematocrit, and hemoglobin were compared to published ranges provided by a contract diagnostic laboratory. Analyzer ranges were computed as the mean +/- 2 standard deviations of the test samples, such that approximately 95% of tested animals would fall within the resultant range. The degree of overlap between analyzer and published ranges, or the percentage of the published range contained within the analyzer range, was calculated for all analytes. For mice, the ranges of 5 of 7 analytes had more than 57% overlap; for rats, ranges for 6 of 7 analytes had over 65% overlap. After the establishment of normal ranges, the analyzer was used to confirm hyperglycemia in Type I diabetic mice and elevated BUN in rats with induced glomerulosclerosis. The portable analyzer can be a valuable screening tool for both phenotyping and clinical care of rodents, with potential for investigations of both spontaneous and experimental disease in laboratory rodents.
