1. Mitigation of the hematopoietic and gastrointestinal acute radiation syndrome by octadecenyl thiophosphate, a small molecule mimic of lysophosphatidic acid.
- Author
-
Deng W, Kimura Y, Gududuru V, Wu W, Balogh A, Szabo E, Thompson KE, Yates CR, Balazs L, Johnson LR, Miller DD, Strobos J, McCool WS, and Tigyi GJ
- Subjects
- ATPases Associated with Diverse Cellular Activities, Adaptor Proteins, Signal Transducing metabolism, Animals, Antigens, CD34 metabolism, Biological Transport drug effects, Biological Transport radiation effects, Biomimetic Materials adverse effects, Biomimetic Materials pharmacokinetics, Biomimetic Materials pharmacology, Cell Survival drug effects, Cell Survival radiation effects, Clone Cells cytology, Clone Cells drug effects, Clone Cells radiation effects, Dose-Response Relationship, Drug, Female, Gastrointestinal Tract metabolism, Gastrointestinal Tract microbiology, Glucose metabolism, HEK293 Cells, Hematopoietic Stem Cells cytology, Hematopoietic Stem Cells drug effects, Hematopoietic Stem Cells radiation effects, Humans, LIM Domain Proteins metabolism, Leukocyte Count, Mice, Mice, Inbred C57BL, Organophosphorus Compounds adverse effects, Organophosphorus Compounds pharmacokinetics, Phosphoproteins metabolism, Platelet Count, Proteasome Endopeptidase Complex, Radiation-Protective Agents adverse effects, Radiation-Protective Agents pharmacokinetics, Radiation-Protective Agents pharmacology, Sodium-Hydrogen Exchangers metabolism, Transcription Factors metabolism, Whole-Body Irradiation adverse effects, Acute Radiation Syndrome prevention & control, Gastrointestinal Tract drug effects, Gastrointestinal Tract radiation effects, Hematopoiesis drug effects, Hematopoiesis radiation effects, Lysophospholipids metabolism, Organophosphorus Compounds pharmacology
- Abstract
We have previously demonstrated that the small molecule octadecenyl thiophosphate (OTP), a synthetic mimic of the growth factor-like mediator lysophosphatidic acid (LPA), showed radioprotective activity in a mouse model of total-body irradiation (TBI) when given orally or intraperitoneally 30 min before exposure to 9 Gy γ radiation. In the current study, we evaluated the effects of OTP, delivered subcutaneously, for radioprotection or radiomitigation from -24 h before to up to +72 h postirradiation using a mouse TBI model with therapeutic doses at around 1 mg/kg. OTP was injected at 10 mg/kg without observable toxic side effects in mice, providing a comfortable safety margin. Treatment of C57BL/6 mice with a single dose of OTP over the time period from -12 h before to +26 h after a lethal dose of TBI reduced mortality by 50%. When administered at +48 h to +72 h postirradiation (LD50/30 to LD100/30), OTP reduced mortality by ≥34%. OTP administered at +24 h postirradiation significantly elevated peripheral white blood cell and platelet counts, increased crypt survival in the jejunum, enhanced intestinal glucose absorption and reduced endotoxin seepage into the blood. In the 6.4-8.6 Gy TBI range using LD50/10 as the end point, OTP yielded a dose modification factor of 1.2. The current data indicate that OTP is a potent radioprotector and radiomitigator ameliorating the mortality and tissue injury of acute hematopoietic as well as acute gastrointestinal radiation syndrome.
- Published
- 2015
- Full Text
- View/download PDF