Drugs are an important cause of liver injury. More than 900 drugs, toxins, and herbs have been reported to cause liver injury, and drugs account for 20-40% of all instances of fulminant hepatic failure.
Approximately 75% of the idiosyncratic drug reactions result in liver transplantation or death. Drug-induced hepatic injury is the most common reason cited for withdrawal of an approved drug.
Physicians must be vigilant in identifying drug-related liver injury because early detection can decrease the severity of hepatotoxicity if the drug is discontinued. The manifestations of drug-induced hepatotoxicity are highly variable, ranging from asymptomatic elevation of liver enzymes to fulminant hepatic failure. Knowledge of the commonly implicated agents and a high index of suspicion are essential in diagnosis.
At Sygnature Discovery we have developed and validated a number of robust assays to help elucidate specific mechanisms of hepatotoxicity during the discovery optimisation process.
Using cutting-edge technologies, we can identify and understand the cellular, biochemical and molecular basis by which chemicals exert toxic effects. An in-depth understanding of these mechanisms will enable us to better monitor and build SAR to re-engineer the lead molecules and subsequently overcome specific toxic liabilities.
Early assessment of cellular toxicity responses enable our team to create safer candidates that significantly increases the chance of clinical progression in drug discovery. This is reflected in our excellent track record of delivering candidates that progress to human dosing.
As part of our panel of toxicity assays we offer the following capabilities:
- Mitochondrial toxicity (Glu/Gal or Mitotox Glow) – compares cytotoxicity using cells grown in glucose and galactose media to determine mitochondrial impairment.
- Functional mitochondrial toxicity – uses the Seahorse Xfp extracellular flux analyser to determine oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) to assess cellular bioenergetics and potential mechanisms of mitochondrial toxicity.
- Reactive metabolite assessment – uses LC-MS/MS detection to identify glutathione or cyanide adducts in trapping studies whilst incubating drug with human liver microsomes.
- Cell viability – general cell viability assessment using Resazurin.
- Phospholipidosis – assesses accumulation of intracellular phospholipids in tissues, via excessive lysosomal storage, in response to drug candidate.
- Steatosis – assessing drug induced accumulation of triglycerides/lipids within the liver cells.
- Lysosomal trapping – investigates accumulation of the drug in the lysosomes.
- Toxicological gene regulation – using qRT-PCR to measure toxicologically relevant changes in gene expression. Alternatively, cost-effective options using reporter-gene assays are also available.
- Custom toxicology – flexible service where we can propose use of different cell lines, endpoints and time points to address particular customer concerns.
For the assays above a number of cell lines are available in 2D, 3D and spheroid cultures. These 3D models offer the possibility to carry out long-term repeat dose studies which are not possible using 2D systems. Also, 3D cellular models closely mimic native tissues and have the benefit of cell to cell interaction. We also have experience to culture primary hepatocytes in monolayer and sandwich cultures.
Sygnature Discovery’s expertise in tissue culture is complemented with high content imaging platforms (e.g. ImageXpress®, IncuCyte® ) as well as modern molecular (e.g. qRT-PCR) and biochemical techniques (e.g. AlphaLISA).
We are also equipped with state-of-the-art high-resolution accurate mass spectrometry capabilities. Such instruments provide increased sensitivity and enhanced structural characterisation. Sygnature’s metabolite identification team can access either the Sciex QTRAP® 5500 or the Waters Xevo® G2-S QTof to determine high-resolution accurate mass of any metabolites.