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Clearance kinetics, biodistribution, and organ saturability of phosphorothioate oligodeoxynucleotides in mice
1Department of Pathology, Rhode Island Hospital, Brown University School of Medicine, Providence 02903, USA.
Abstract:
We examined the dynamics of removal from circulation, tissue distribution, and persistence of phosphorothioate oligodeoxynucleotides (S-ODN) anti-tumor-necrosis-factor and a control of random sequence (randomer) in mice. After intravenous injection, the majority (96%) of S-ODN cleared rapidly from the circulation in the first two phases. In the first phase, 37.8 +/- 2.3% of the radioactivity had a mean half-life (t1/2) of 2.0 +/- 0.4 minutes. In the second phase, 58.1 +/- 1.5% of the radioactivity cleared with t1/2 of 12.6 +/- 0.2 minutes. The catabolic phase, constituting a minor proportion (4.1 +/- 0.8% of the total radioactivity), had a mean t1/2 of 2.7 +/- 0.5 hours. At a low dose (1 microgram) tissue distribution of both S-ODN anti-tumor-necrosis-factor and randomer were similar. The liver and kidneys were the major organs involved in uptake and removal of S-ODN. Autoradiographic studies showed the liver Kupffer cells to be the major site of uptake and renal urinary space for elimination. The clearance rate from the circulation was increased with the dose of S-ODN. In contrast, the fraction of radioactivity localized in the kidneys, liver, and spleen was decreased with increase in dosage. Furthermore, at a high dose (200 micrograms), the tissue distribution of the S-ODN anti-tumor-necrosis-factor differed significantly from the randomer. These findings have general significance in showing that the liver and kidneys are the major organs for removal of S-ODN and these organs are saturable at high doses. In addition, the results have specific importance in defining different parameters, dose and base composition, that affect utilization of antisense oligonucleotides for controlling gene expression in vivo.
Insights
Phosphorothioate oligodeoxynucleotides (S-ODN) rapidly clear from circulation, with liver and kidneys being primary removal organs. High doses saturate these organs and alter S-ODN distribution, impacting gene expression control.
Area of Science:
- Pharmacokinetics and Drug Metabolism
- Molecular Biology
- Oligonucleotide Therapeutics
Background:
- Antisense oligonucleotides (ASO) are promising for gene expression control.
- Understanding the in vivo behavior of phosphorothioate oligodeoxynucleotides (S-ODN) is crucial for therapeutic development.
Purpose of the Study:
- To investigate the pharmacokinetics, tissue distribution, and persistence of S-ODN targeting tumor necrosis factor (TNF) in mice.
- To evaluate the impact of dosage on S-ODN clearance and tissue localization.
Main Methods:
- Intravenous injection of radiolabeled S-ODN and a random sequence control in mice.
- Analysis of S-ODN clearance from circulation using multi-phase exponential decay models.
- Autoradiography and tissue counting to determine S-ODN distribution and identify primary uptake and elimination sites.
Main Results:
- S-ODN rapidly cleared from circulation in two main phases with short half-lives, followed by a slower catabolic phase.
- Liver and kidneys were the major organs for S-ODN uptake and elimination, with Kupffer cells and renal urinary space identified as key sites.
- Low doses showed similar distribution for S-ODN and randomer, but high doses led to significant differences in tissue distribution and saturable uptake in liver and kidneys.
Conclusions:
- The liver and kidneys are the primary organs responsible for S-ODN removal from circulation.
- S-ODN clearance and tissue distribution are dose-dependent, with saturation occurring at high doses.
- These findings are critical for optimizing the use of antisense oligonucleotides for in vivo gene expression modulation.