Cytoprotection of human endothelial cells from oxidant stress with CDDO derivatives: network analysis of genes responsible for cytoprotection.

AIM: To identify drugs that may reduce the impact of oxidant stress on cell viability. METHODS: Human umbilical vein endothelial cells were treated with 200 nmol/l CDDO-Im (imidazole) and CDDO-Me (methyl) after exposure to menadione and compared to vehicle-treated cells. Cell viability and cytotoxicity were assessed, and gene expression profiling was performed. RESULTS: CDDO-Im was significantly more cytoprotective and less cytotoxic (p < 0.001) than CDDO-Me. Although both provided cytoprotection by induction of gene transcription, CDDO-Im induced more genes. In addition to a higher induction of the key cytoprotective gene heme oxygenase-1 (38.9-fold increase for CDDO-Im and 26.5-fold increase for CDDO-Me), CDDO-Im also induced greater expression of heat shock proteins (5.5-fold increase compared to 2.8-fold for CDDO-Me). CONCLUSIONS: Both compounds showed good induction of heme oxygenase, which largely accounted for their cytoprotective effect. Differences were detected in cytotoxicity at higher doses, indicating that CDDO-Me was more cytotoxic than CDDO-Im. Significant differences were detected in the ability of CDDO-Im and CDDO-Me to affect differential gene transcription. CDDO-Im induced more genes than did CDDO-Me. The source of the differences in gene expression patterns between CDDO-Im and CDDO-Me was not determined but may be important in long-term use of this class of drugs.

Critical research gaps in electronic cigarette devices and nicotine aerosols.

Electronic cigarettes (e-cigs) are devices that aerosolize nicotine-containing liquids for delivery as an inhaled vapor. E-cigs are currently marketed as smoking cessation devices, though the emergence and rapid adoption of these devices in recent years has sparked a great deal of concern over their safety. Given the plethora of devices and nicotine solutions available on the market and the lack of regulation and quality control, it is imperative that these devices and nicotine formulations are studied to assess critical operating parameters, the pharmacokinetic profiles of the inhaled nicotine, and the toxicity profiles of the e-cig aerosols. This review aims to deliver an overview of current research regarding electronic cigarette devices, nicotine-containing liquid formulations, pharmacokinetics of nicotine, and toxicology studies in order to highlight areas lacking in research or requiring greater standardization and regulation.

Time Course Expression Analysis of 1[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole Induction of Cytoprotection in Human Endothelial Cells.

1[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im), a synthetic derivative of oleanolic acid that exhibits antioxidant and anti-inflammatory activity in several animal and in vitro models, has been shown to be beneficial if given after injury. Although induction of heme oxygenase 1 appears to be a major effector of cytoprotection, the mechanism by which the overall effect is mediated is largely unknown. This study evaluated temporal gene expression profiles to better characterize the early transcriptional events and their relationship to the dynamics of the cytoprotective response in human umbilical vein endothelial cells (HUVEC) to CDDO-Im. Time-course gene expression profiling was performed on HUVEC treated with CDDO-Im for 0.5, 1, 3, 6, and 24 hours. More than 10 000 genes were statistically altered in their expression in at least 1 time point across the time course. Large alterations in immediate-early gene expression were readily detectable within 0.5 hour after administration of CDDO-Im.

The use of BDDCS in classifying the permeability of marketed drugs.

We recommend that regulatory agencies add the extent of drug metabolism (i.e., >or=90% metabolized) as an alternate method in defining Class 1 marketed drugs suitable for a waiver of in vivo studies of bioequivalence. That is, >or=90% metabolized is an additional methodology that may be substituted for >or=90% absorbed. We propose that the following criteria be used to define>or=90% metabolized for marketed drugs: Following a single oral dose to humans, administered at the highest dose strength, mass balance of the Phase 1 oxidative and Phase 2 conjugative drug metabolites in the urine and feces, measured either as unlabeled, radioactive labeled or nonradioactive labeled substances, account for >or=90% of the drug dosed. This is the strictest definition for a waiver based on metabolism. For an orally administered drug to be >or=90% metabolized by Phase 1 oxidative and Phase 2 conjugative processes, it is obvious that the drug must be absorbed. This proposal, which strictly conforms to the present>or=90% criteria, is a suggested modification to facilitate a number of marketed drugs being appropriately assigned to Class 1.

Effect of interleukin-1beta and tumor necrosis factor-alpha on gene expression in human endothelial cells.

Interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) are two major cytokines that rise to relatively high levels during systemic inflammation, and the endothelial cell (EC) response to these cytokines may explain some of the dysfunction that occurs. To better understand the cytokine-induced responses of EC at the gene expression level, human umbilical vein EC were exposed to IL-1beta or TNF-alpha for various times and subjected to cDNA microarray analyses to study alterations in their mRNA expression. Of approximately 4,000 genes on the microarray, expression levels of 33 and 58 genes appeared to be affected by treatment with IL-1beta and TNF-alpha, respectively; 25 of these genes responded to both treatments. These results suggest that the effects of IL-1beta and TNF-alpha on EC are redundant and that it may be necessary to suppress both cytokines simultaneously to ameliorate the systemic response.

Molecular properties of WHO essential drugs and provisional biopharmaceutical classification.

The purpose of this study is to provisionally classify, based on the Biopharmaceutics Classification System (BCS), drugs in immediate-release dosage forms that appear on the World Health Organization (WHO) Essential Drug List. The classification in this report is based on the aqueous solubility of the drugs reported in commonly available reference literature and a correlation of human intestinal membrane permeability for a set of 29 reference drugs with their calculated partition coefficients. The WHO Essential Drug List consists of a total of 325 medicines and 260 drugs, of which 123 are oral drugs in immediate-release (IR) products. Drugs with dose numbers less than or equal to unity [Do = (maximum dose strength/250 mL)/solubility < or = 1] are defined as high-solubility drugs. Drug solubility for the uncharged, lowest-solubility form reported in the Merck Index or USP was used. Of the 123 WHO oral drugs in immediate-release dosage forms, 67% (82) were determined to be high-solubility drugs. The classification of permeability is based on correlations of human intestinal permeability of 29 reference drugs with the estimated log P or CLogP lipophilicity values. Metoprolol was chosen as the reference compound for permeability and log P or CLogP. Log P and CLogP were linearly correlated (r2 = 0.78) for 104 drugs. A total of 53 (43.1%) and 62 (50.4%) drugs on the WHO list exhibited log P and CLogP estimates, respectively, that were greater than or equal to the corresponding metoprolol value and are classified as high-permeability drugs. The percentages of the drugs in immediate-release dosage forms that were classified as BCS Class 1, Class 2, Class 3, and Class 4 drugs using dose number and log Pwere as follows: 23.6% in Class 1, 17.1% in Class 2, 31.7% in Class 3, and 10.6% in Class 4. The remaining 17.1% of the drugs could not be classified because of the inability to calculate log P values because of missing fragments. The corresponding percentages in the various BCS classes with dose number and CLogP criteria were similar: 28.5% in Class 1, 19.5% in Class 2, 35.0% in Class 3, and 9.8% in Class 4. The remaining 7.3% of the drugs could not be classified since CLogP could not be calculated. These results suggest that a satisfactory bioequivalence (BE) test for more than 55% of the high-solubility Class 1 and Class 3 drug products on the WHO Essential Drug List may be based on an in vitro dissolution test. The use of more easily implemented, routinely monitored, and reliable in vitro dissolution tests can ensure the clinical performance of drug products that appear on the WHO Essential Medicines List.