Can Galactose Be Converted to Glucose in HepG2 Cells? Improving the in Vitro Mitochondrial Toxicity Assay for the Assessment of Drug Induced Liver Injury.

Human hepatocellular carcinoma cells, HepG2, are often used for drug mediated mitochondrial toxicity assessments. Glucose in HepG2 culture media is replaced by galactose to reveal drug-induced mitochondrial toxicity as a marked shift of drug IC50 values for the reduction of cellular ATP. It has been postulated that galactose sensitizes HepG2 mitochondria by the additional ATP consumption demand in the Leloir pathway. However, our NMR metabolomics analysis of HepG2 cells and culture media showed very limited galactose metabolism. To clarify the role of galactose in HepG2 cellular metabolism, U-13C6-galactose or U-13C6-glucose was added to HepG2 culture media to help specifically track the metabolism of those two sugars. Conversion to U-13C3-lactate was hardly detected when HepG2 cells were incubated with U-13C6-galactose, while an abundance of U-13C3-lactate was produced when HepG2 cells were incubated with U-13C6-glucose. In the absence of glucose, HepG2 cells increased glutamine consumption as a bioenergetics source. The requirement of additional glutamine almost matched the amount of glucose needed to maintain a similar level of cellular ATP in HepG2 cells. This improved understanding of galactose and glutamine metabolism in HepG2 cells helped optimize the ATP-based mitochondrial toxicity assay. The modified assay showed 96% sensitivity and 97% specificity in correctly discriminating compounds known to cause mitochondrial toxicity from those with prior evidence of not being mitochondrial toxicants. The greatest significance of the modified assay was its improved sensitivity in detecting the inhibition of mitochondrial fatty acid ß-oxidation (FAO) when glutamine was withheld. Use of this improved assay for an empirical prediction of the likely contribution of mitochondrial toxicity to human DILI (drug induced liver injury) was attempted. According to testing of 65 DILI positive compounds representing numerous mechanisms of DILI together with 55 DILI negative compounds, the overall prediction of mitochondrial mechanism-related DILI showed 25% sensitivity and 95% specificity.

Performance of biomarkers NF-L, NSE, Tau and GFAP in blood and cerebrospinal fluid in rat for the detection of nervous system injury.

Background: Target organ toxicity is often a reason for attritions in nonclinical and clinical drug development. Leveraging emerging safety biomarkers in nonclinical studies provides an opportunity to monitor such toxicities early and efficiently, potentially translating to early clinical trials. As a part of the European Union's Innovative Medicines Initiative (IMI), two projects have focused on evaluating safety biomarkers of nervous system (NS) toxicity: Translational Safety Biomarker Pipeline (TransBioLine) and Neurotoxicity De-Risking in Preclinical Drug Discovery (NeuroDeRisk). Methods: Performance of fluid-based NS injury biomarker candidates neurofilament light chain (NF-L), glial fibrillary acidic protein (GFAP), neuron specific enolase (NSE) and total Tau in plasma and cerebrospinal fluid (CSF) was evaluated in 15 rat in vivo studies. Model nervous system toxicants as well as other compounds were used to evaluate sensitivity and specificity. Histopathologic assessments of nervous tissues and behavioral observations were conducted to detect and characterize NS injuries. Receiver operator characteristic (ROC) curves were generated to compare the relative performance of the biomarkers in their ability to detect NS injury. Results: NF-L was the best performer in detecting both peripheral nervous system (PNS) and CNS injury in plasma, (AUC of 0.97-0.99; respectively). In CSF, Tau correlated the best with CNS (AUC 0.97), but not PNS injury. NSE and GFAP were suitable for monitoring CNS injury, but with lesser sensitivity. In summary, NF-L is a sensitive and specific biomarker in rats for detecting compound-induced central and peripheral NS injuries. While NF-L measurement alone cannot inform the site of the injury, addition of biomarkers like Tau and NSE and analysis in both blood and CSF can provide additional information about the origin of the NS injury. Conclusion: These results demonstrate the utility of emerging safety biomarkers of drug-induced NS injury in rats and provide additional supporting evidence for biomarker translation across species and potential use in clinical settings to monitor drug-induced NS injury in patients.

Delayed hemolysis, elevated liver enzymes, low platelet count syndrome in succession of switches of preventive anticoagulant treatment in a 41-year-old patient with a history of recurrent assisted implantation failures: a case report.

BACKGROUND: For the past decades the mean age of primiparae in Western societies is constantly increasing. At the same time, there is a growing demand for assisted reproductive technologies such as in vitro fertilization and intracytoplasmic sperm injection. Subsequently, a higher prevalence of pregnancy-associated diseases such as gestational hypertension and preeclampsia is observed. To improve pregnancy rates after in vitro fertilization/intracytoplasmic sperm injection and to reduce the risk of pregnancy-associated diseases with a cardiovascular pathophysiology, two anticoagulants are the focus of current research: low molecular weight heparin and acetylsalicylic acid (aspirin). CASE PRESENTATION: A 41-year-old white woman, gravida 3, para 0, received low molecular weight heparin to reduce the risk of abortion after five unsuccessful intracytoplasmic sperm injections and two miscarriages. She autonomously discontinued the medication with low molecular weight heparin at 12 weeks and 2 days of gestation and took aspirin instead until 24 weeks and 2 days of gestation as preeclampsia prophylaxis. However, the pregnancy ended with an urgent cesarean section at 27 weeks and 4 days of gestation due to a fast progressing hemolysis, elevated liver enzyme levels, and low blood platelet count syndrome, a potentially life-threatening variant of preeclampsia. CONCLUSION: Based on the current demographic trend toward late-in-life pregnancy it is mandatory to establish clear guidelines concerning preventive treatment options of preeclampsia for patients with risk factors. The establishment of a special first-trimester screening for these women should be discussed. Moreover, it is necessary to raise the awareness among physicians of these contemporary issues to guarantee the best possible medical care.

Exploration of long-acting implant formulations of hepatitis B drug entecavir.

Alternative formulations of entecavir, a once daily oral hepatitis B antiretroviral, may improve treatment adherence by patients. We explored the use of biocompatible polymers to control entecavir dissolution in two formats suitable for subcutaneous implantation. Hot melt extrudates were prepared by extruding entecavir-polymer blends at specified weight ratios. Dip-coated tablets were prepared by compressing entecavir in a multi-tip tooling. Tablets were dip-coated in solutions of polymer and dried. In rodents, entecavir-poly(caprolactone) extrudates demonstrated >180 days of continuous drug release, although below the estimated efficacious target input rate. Drug pharmacokinetic profiles were tunable by varying the polymer employed and implant format. The rank order trends of drug input rates observed in vitro were observed in vivo in the detected plasma concentrations of entecavir. In all dose groups entecavir was not tolerated locally at the site of administration where adverse event severity correlated with drug input rate. These polymer-based implantable formats have applicability to long-acting formulations of high solubility compounds beyond entecavir.

24-hour intravenous infusion via the marginal ear vein in the New Zealand white rabbit.

A method was needed to conduct a 24-h intravenous infusion procedure in rabbits that minimized animal restraint and allowed unlimited access to the animal by research staff. We catheterized 16 male and 16 female New Zealand White rabbits (Oryctolagus cuniculus) by inserting an indwelling human infant catheter into the marginal ear vein. The catheter was connected, via an extension set, to a small, lightweight, ambulatory pump with predetermined pump rates; the pump was placed in a Lycra jacket that the rabbit was wearing. Toxicokinetic samples, electrocardiograms, and clinical pathology samples were collected at multiple time points. Pump accuracy was verified by collecting the pre- and post-dose weights of the pumps as well as infusion start and stop times. Depending on the infusion rate, pumps were changed every 5 or 10 h or at the end of 24 h. The accuracy of these pumps was between 5% and 10% of the calculated target volume from 0 to 20 h. The lack of need for surgery or long-term restraint and tethering is a refinement in infusion technology and animal use.