The Anticancer Agent Elesclomol Has Direct Effects on Mitochondrial Bioenergetic Function in Isolated Mammalian Mitochondria.

Elesclomol ((N-malonyl-bis(N'-methyl-N'-thiobenzoylhydrazide)); formerly STA-4783) is a mitochondria-targeted chemotherapeutic agent that has demonstrated efficacy in selective cancer cell killing in pre-clinical and clinical testing. The biologically active form of elesclomol is a deprotonated copper chelate (elesclomol:copper; E:C), which has been shown to enhance reactive oxygen species (ROS) production and induce a transcriptional gene profile characteristic of an oxidative stress response in vitro. Previous studies suggest that E:C interacts with the electron transport chain (ETC) to generate high levels of ROS within the organelle and ultimately induce cell death. The purpose of this study was to further explore the mechanism of cellular and mitochondrial toxicity of E:C by examining its direct effect on mitochondrial bioenergetic function. The results obtained indicate that E:C treatment in whole cells of non-tumorigenic origin at high concentrations (40 M and higher) induces a rapid and substantial increase in mitochondrial superoxide levels and dissipation of mitochondrial membrane potential. Furthermore, similar higher concentrations of E:C act as a direct uncoupler of oxidative phosphorylation and generalized inhibitor of electron transport activity in isolated, intact mitochondria, and induce a dose-dependent inhibition of mitochondrial NADH-ubiquinone oxidoreductase activity in freeze-thawed mitochondrial preparations. The results of this study are important in that they are the first to demonstrate a direct effect of the E:C chelate on bioenergetic function in isolated mammalian mitochondria, and suggest the possibility that the increase in ROS production and cytotoxicity induced by E:C may in part be due to uncoupling of mitochondrial oxidative phosphorylation and/or inhibition of electron transport activity. These results also provide important information about the mechanisms of mitochondrial and cellular toxicity induced by E:C and will ultimately contribute to a better understanding of the therapeutic potential of elesclomol as an anticancer compound.

γ-Carboxyethyl hydroxychroman, a metabolite of γ-tocopherol, preserves nitric oxide bioavailability in endothelial cells challenged with high glucose.

Endothelial dysfunction occurs when there are imbalances between factors that regulate the synthesis and degradation of nitric oxide (NO•), and has been reported in patients with hyperglycemia and insulin resistance. We reported that supplementation with γ-tocopherol (γ-T) in humans limits impairments in endothelial function otherwise induced by postprandial hyperglycemia. Given the rapid metabolism of γ-T into γ-carboxyethyl hydroxychroman (γ-CEHC), we hypothesized that the vasoprotective activities of γ-T could be attributed to its metabolite γ-CEHC. To test this, human aortic endothelial cells (HAECs) treated with 0 (vehicle control) or 3 µM γ-CEHC for 24 h prior to incubation with normal (5 mM) or high (25 mM) glucose for 48 h. High-glucose increased levels of uncoupled endothelial nitric oxide synthase (eNOS) as evidenced by reduced ( p < 0.05) eNOS dimer:monomer. High glucose also prevented insulin-stimulated increases in p-AktSer473: total Akt, p-eNOSSer1177: total eNOS, and NO• production. These adverse changes were accompanied by increased ( p < 0.05) reactive oxygen species and mRNA expression of inflammatory mediators (VCAM-1, E-selectin, IL-8). However, each deleterious response evoked by high glucose was prevented when HAECs were incubated with γ-CEHC prior to the high glucose challenge. Taken together, our data support the hypothesis that vascular protection provided by γ-T in vivo may be elicited through the bioactivity of its metabolite, γ-CEHC. Furthermore, it is possible that the antioxidant and anti-inflammatory activities of γ-CEHC may mediate this protective activity.

Efectos del extracto de té verde sobre los daños oxidativos inducidos por cisplatino en riñones y testículos de ratas / Effect of green tea extract on cisplatin induced oxidative damage on kidney and testes of rats

Se administró extracto de té verde (Camellia sinensis) por vía oral a las ratas en dosis de 25, 50 y 100 mg/kg para investigar sus efectos sobre la nefrotoxicidad y la toxicidad testicular inducida por cisplatino (3mg/kg). El extracto de té verde restauró el nivel de creatinina, urea, nitrógeno ureico en sangre (NUS) y ácido úrico en el suero de animales tratados con cisplatino en comparación con los animales tratados sólo con cisplatino. Además, se observó que la administración de extracto de té verde restauró los niveles de enzimas antioxidantes como superóxido dismutasa (SOD), catalasa (CAT) y glutatión reducido (GSH), y enzimas ligadas a la membrana como Na Na+K+ATPasa, Ca Ca2+ 2+ ATPasa y Mg Mg2+ 2+ ATPasa y redujo la peroxidación lipídica (MDA) en los riñones y en los testículos de animales con alteraciones tras el tratamiento crónico con cisplatino. Por tanto, se puede concluir que el extracto de té verde posee actividad antioxidante y que, en virtud de esta acción, puede proteger los riñones y los testículos frente a los daños oxidativos inducidos por el cisplatino

Green tea extract (Camellia sinensis) was administered orally to rats at the dose levels of 25, 50,100 mg/kg to investigate its effect on cisplatin (3mg/kg) induced nephrotoxicity and testicular toxicity. Green tea extract restored the level of creatinine, urea, blood urea nitrogen (BUN) and uric acid in serum of animals treated with cisplatin as compared to the animals treated with cisplatin alone. It was further found that administration of green tea extract restored the level of antioxidant enzymes such as, superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH), and membrane bound enzymes like Na Na+K+ ATPase, Ca Ca2+ 2+ ATPase and Mg Mg2+ 2+ ATPase and decreased lipid peroxidation (MDA) in kidney and in testes of animals which were altered after chronic treatment with cisplatin. Thus it can be concluded that green tea extract possesses antioxidant activity and by virtue of this action it can protect the kidney and testes from cisplatin induced oxidative damage

Effect of a single course of isotretinoin therapy on bone mineral density in adolescent patients with severe, recalcitrant, nodular acne.

BACKGROUND: Adverse changes in bone have been reported for patients undergoing high-dose, long-term (several years) isotretinoin therapy for disorders of cornification. The effect of short-term (4-5 months) therapy at the lower dose recommended for acne on bone development in younger, growing adolescent (12-17 years) patients has not been well studied. OBJECTIVE: The purpose of the study was to evaluate the effect of a standard, single course of isotretinoin (Accutane) therapy on bone mineral density (BMD) of the lumbar spine and hip in adolescents ages 12 to 17 years with severe, recalcitrant, nodular acne. METHODS: In this open-label, multicenter study, 217 adolescents (81 girls) with severe, recalcitrant, nodular acne were enrolled and treated with isotretinoin twice daily with food at the recommended total dose of approximately 1 mg/kg for 16 to 20 weeks. BMD in the lumbar spine and hip was measured at baseline and at the end of therapy by dual energy radiograph absorptiometry. RESULTS: There was no clinically significant mean change in BMD measured at the lumbar spine (+1.4%, range: -4.9% to +12.3%) or total hip (-0.26%, range: -11.3% to +15.0%). Hyperostosis was not observed in any patient. Typical efficacy expected in the treatment of acne was observed. CONCLUSIONS: A 16- to 20-week course of isotretinoin treatment at the recommended dose for severe acne has no clinically significant effect on lumbar spine and total hip BMD in the adolescent (12-17 years) population.

Echinacea purpurea for prevention of experimental rhinovirus colds.

A randomized, double-blind, placebo-controlled clinical trial was conducted to evaluate the ability of Echinacea purpurea to prevent infection with rhinovirus type 39 (RV-39). Forty-eight previously healthy adults received echinacea or placebo, 2.5 mL 3 times per day, for 7 days before and 7 days after intranasal inoculation with RV-39. Symptoms were assessed to evaluate clinical illness. Viral culture and serologic studies were performed to evaluate the presence of rhinovirus infection. A total of 92% of echinacea recipients and 95% of placebo recipients were infected. Colds developed in 58% of echinacea recipients and 82% of placebo recipients (P=.114, by Fisher's exact test). Administration of echinacea before and after exposure to rhinovirus did not decrease the rate of infection; however, because of the small sample size, statistical hypothesis testing had relatively poor power to detect statistically significant differences in the frequency and severity of illness.