Modulation of ascorbic acid metabolism by cytochrome P450 induction revealed by metabonomics and transcriptional profiling

Recent Advances in Drug Discovery Toxicology

Major advances in scientific discovery and insights that stem from the development and use of new techniques and models can bring remarkable progress to conventional toxicology. Although animal testing is still considered as the "gold standard" in traditional toxicity testing, there is a necessity for shift from animal testing to alternative methods regarding the drug safety testing owing to the emerging state-of-art techniques and the proposal of 3Rs (replace, reduce, and refine) towards animal welfare. This review describes some recent research methods in drug discovery toxicology, including in vitro cell and organ-on-a-chip, imaging systems, model organisms (C. elegans, Danio rerio, and Drosophila melanogaster), and toxicogenomics in modern toxicology testing.

Acute and subacute hepatotoxicity of genipin in mice and its potential mechanism

Gardenia, as a medicinal and edible herb, has the pharmacological activity of protecting the liver and cholagogue, but the hepatotoxicity induced by the chemical component genipin (GP) limits its application. The aim of this study was to evaluate the acute and subacute hepatotoxicity of genipin in normal mice and mice with α-naphthalene isothiocyanate (ANIT)-induced liver injury. The results of the acute study showed that the LD50 of genipin was 510 mg/kg. Genipin exhibited hepatotoxicity in normal and jaundiced mice at doses of 125 mg/kg, 250 mg/kg, and 500 mg/kg, which increased with dose. In a 28-day subacute study, the 50 mg/kg and 100 mg/kg dose groups showed some pharmacodynamic effects at 7 days but exhibited hepatotoxicity that increased with time and improved after drug withdrawal. In addition, based on proteomics, the mechanism of liver injury induced by genipin may be related to the disruption of the UDP-glucuronosyltransferase system and cytochrome P450 enzyme activity. In conclusion, this study showed that genipin hepatotoxicity was time- and dose dependent, but it is worth mentioning that hepatotoxicity was reversible. It is hoped that this study will provide a scientific basis for circumventing the adverse effects of genipin.

Metabolomics in the pharmaceutical industry

Metabolomics has roots in the pharmaceutical industry that go back nearly three decades. Initially focused on applications in toxicology and disease pathology, more recent academic and commercial efforts have helped advance metabolomics as a tool to reveal the molecular basis of biological processes and pharmacological responses to drugs. This article will discuss areas where metabolomic technologies and applications are poised to have the greatest impact in the discovery and development of pharmaceuticals.

Assessment of urinary metabolite excretion after rat acute exposure to perfluorooctanoic acid and other peroxisomal proliferators

Perfluorooctanoic acid (PFOA) is a persistent environmental contaminant. Activation of the peroxisome proliferator activated receptor alpha (PPARα) resulting from exposure to PFOA has been extensively studied in rodents. However, marked differences in response to peroxisome proliferators prevent extrapolation of rodent PPARα activation to human health risks and additional molecular mechanisms may also be involved in the biological response to PFOA exposure. To further explore the potential involvement of such additional pathways, the effects of PFOA exposure on urinary metabolites were directly compared with those of other well-known PPARα agonists. Male rats were administered PFOA (10, 33, or 100 mg/kg/d), fenofibrate (100 mg/kg/d), or di(2-ethylhexyl) phthalate (100 mg/kg/d) by gavage for 3 consecutive days and allowed to recover for 4 days, and overnight urine was collected. Greater urinary output was observed exclusively in PFOA-treated rats as the total fraction of PFOA excreted in urine increased with the dose administered. Assessment of urinary metabolites (ascorbic acid, quinolinic acid, 8-hydroxy-2'-deoxyguanosine, and malondialdehyde) provided additional information on PFOA's effects on hepatic glucuronic acid and tryptophan-nicotinamide adenine dinucleotide (NAD) pathways and on oxidative stress, whereas increased liver weight and palmitoyl-CoA oxidase activity indicative of PPARα activation and peroxisomal proliferation persisted up to day five after the last exposure.

Bioinformatics assistance of metabolic and nutrition management in the ICU

PURPOSE OF REVIEW

To review the domains in which computerized information systems have proven beneficial in facilitating the metabolic and nutritional management

RECENT FINDINGS

In glucose control, computerized insulin algorithms have proven safer and more efficient than manual systems, reducing workload, time to target glycemia and numbers of hypoglycemic and hyperglycemic events. By rendering the nutritional variables visible through specific customization, computers do improve daily monitoring of energy balance and adherence to guidelines, particularly for substrate delivery. Nurse-centered systems have shown to be the most successful to enable routine workflow based on protocol-based care.

SUMMARY

Computers are needed to analyze the increasing amount of data collected from critically ill patients from monitoring systems, laboratories and other sources. Studies have shown that computerized information systems do facilitate glucose control, helping reducing hypoglycemic events. They also improve nutritional monitoring (energy delivery and balance, protein and fat delivery), and quality of nutrition. They reduce nurse workload associated with the multiple balance calculations and ease visualization of events out of planned targets. Though integrated systems are expensive, they improve work efficiency.

Advances in mass spectrometry applied to pharmaceutical metabolomics

Metabolomics, also referred to in the literature as metabonomics, is a relatively new systems biology tool for drug discovery and development and is increasingly being used to obtain a detailed picture of a drug's effect on the body. Metabolomics is the qualitative assessment and relative or absolute quantitative measurement of the endogenous metabolome, defined as the complement of all native small molecules (metabolites less than 1,500 Da). A metabolomics study frequently involves the comparative analysis of sample sets from a normal state and a perturbed state, where the perturbation can be of any nature, such as genetic knockout, administration of a drug, or change in diet or lifestyle. Advances in mass spectrometry (MS) technologies including direct introduction or in-line chromatographic separation modes, ionization techniques, mass analyzers, and detection methods have provided powerful tools to assess the molecular changes in the metabolome. This review focuses on advances in MS pertaining to the analytical data generation for the main metabolomics methods, namely, fingerprinting, nontargeted, and targeted approaches, as they are applied to pharmaceutical drug discovery and development.