Hemoproteins, hemoglobin and myoglobin, once released from cells can cause severe oxidative damage as a consequence of heme redox cycling between ferric and ferryl states that generates radical species that induce lipid peroxidation. We demonstrate in vitro that acetaminophen inhibits hemoprotein-induced lipid peroxidation by reducing ferryl heme to its ferric state and quenching globin radicals. Severe muscle injury (rhabdomyolysis) is accompanied by the release of myoglobin that becomes deposited in the kidney, causing renal injury. We previously showed in a rat model of rhabdomyolysis that redox cycling between ferric and ferryl myoglobin yields radical species that cause severe oxidative damage to the kidney. In this model, acetaminophen at therapeutic plasma concentrations significantly decreased oxidant injury in the kidney, improved renal function, and reduced renal damage. These findings also provide a hypothesis for potential therapeutic applications for acetaminophen in diseases involving hemoprotein-mediated oxidative injury.
1 September 2011 in Free Radical Biology and Medicine
2-Hydroxybenzylamine (2-HOBA) is a selective scavenger of dicarbonyl electrophiles that protects proteins and lipids from being modified by these electrophiles. It is currently being developed for use as a nutritional supplement to help maintain good health and protect against the development of conditions associated with dicarbonyl electrophile formation, such as the cognitive decline associated with Mild Cognitive Impairment and Alzheimer’s disease. In this first-in-human study, the safety, tolerability, and pharmacokinetics of six ascending single oral doses of 2-HOBA acetate were tested in eighteen healthy human volunteers. Reported adverse events were mild and considered unlikely to be related to 2-HOBA. There were no clinically significant changes in vital signs, ECG recordings, or clinical laboratory parameters. 2-HOBA was fairly rapidly absorbed, with a tmax of 1–2 h, and eliminated, with a t1/2 of approximately 2 h. Both tmax and t1/2 were independent of dose level, while Cmax and AUC increased proportionally with dose level. 2-HOBA acetate was safe and well-tolerated at doses up to 825 mg in healthy human volunteers, positioning it as a good candidate for continued development as a nutritional supplement. This study is registered at ClinicalTrials.gov (NCT03176940).
31 December 2009 in Chemical Research in Toxicology
The formation of cyclooxygenase‐derived lipid adducts of protein in brains of patients who had Alzheimer's disease has been investigated. The enzymatic product of the cyclooxygenases, prostaglandin H2, rearranges in part to highly reactive γ‐ketoaldehydes, levuglandin (LG) E2 and LGD2. These γ‐ketoaldehydes react with free amines on proteins to yield a covalent adduct. Utilizing analysis of the levuglandinyl‐lysine adducts by liquid chromatography‐tandem mass spectrometry, we now find that this post‐translational modification is increased significantly in the hippocampus in Alzheimer's disease. The magnitude of the increase correlates with the pathological evidence of severity.