ZeEfficacy – Efficacy Services

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Non-Alcoholic Fatty Liver Disease (NAFLD) Model

Non-alcoholic fatty liver disease (NAFLD) is the term for a range of conditions caused by a buildup of fat in the liver cells. It's usually seen in people who are overweight or obese. If it is not detected and managed at early stages, it can progress to non-alcoholic steatohepatitis (NASH), a more serious form of NAFLD, where the liver has become inflamed and the liver cells injured, and even lead to fibrosis, cirrhosis, and finally liver failure.

The increase in the global prevalence of NAFLD has turned into an epidemic, urgently requiring effective therapies. ZeClinics provides high-quality NAFLD preclinical CRO services in order to help clients develop new treatments for NAFLD.

Zebrafish fat metabolism is highly conserved with humans. Indeed, zebrafish express all main nuclear receptors, lipid transporters, apolipoproteins, and enzymes involved in lipoprotein metabolism. Even the activity of the cholesteryl ester transfer protein (CETP), which is naturally deficient in rodents, is detected in zebrafish plasma.

Feeding zebrafish with High Cholesterol (HC), High-Fat (HF), High-Fat Carbohydrates (HFC), or Extra Feeding (EF) diets results in a significantly increased fat liver (steatosis). This makes zebrafish an attractive model to study lipid metabolism and human NAFLD condition.

As a pioneer preclinical CRO in the metabolic field in zebrafish, we help our clients to move forward quickly with their gene candidates. We deliver diet-induced and benchmarked zebrafish models of human NAFLD to evaluate the efficacy of potential hepatic steatosis-modulating genes. These nutritional disease models can be conducted with zebrafish at different life stages (larvae, juvenile and adult fish) according to the clients' experimental needs.

Applications

  • Study the impact of nutritional interventions on liver steatosis and the development of NAFLD.
  • Genetic functional studies of potential hepatic steatosis-modulating genes (target validation).

Advantages

Fat metabolism in zebrafish and humans is remarkably similar.

Rapid induction of liver steatosis with short dietary interventions.

In vivo model suitable for obtaining valuable insights on complex metabolic processes.

Method description

We have established three zebrafish models of steatosis at different life stages, with distinct dietary interventions:

Larval approach

Early-life embryos are fed a Control Diet (CD) versus a HC diet and EF for 10 days in the desired genetic background. Lipid staining is then performed to quantify the liver fat accumulation of zebrafish larvae.

Figure 1. Hepatic steatosis. A) Representative images of liver fat accumulation in zebrafish larvae after Control Diet (CD), High Cholesterol diet (HC), and Extra Feeding diet (EF). B) Quantification of steatosis as negative, mild, or severe according to the fish fraction of fat accumulation in zebrafish larvae fed a CD vs. HC and EF.

Juvenile approach

Juvenile zebrafish are fed a Control Diet (CD) versus a HFC diet for 10 days in the desired genetic background. Lipid staining is then performed to quantify the liver fat accumulation of zebrafish larvae.

Figure 2. Hepatic steatosis in juvenile fish. Fish are fed for 10 days with a Control Diet (CD), or High-Fat Carbohydrates diet (HFC). A) Specific lipid staining for evaluation of liver steatosis. Fat accumulation in the liver is observed in fish fed with HFC. B) Steatotic liver quantification. The amount of dye per fish and diet is measured as mean intensity. Statistical analyses have shown differences between CD and HFC. Means and SEM are plotted. *** p<0.001 vs CD.

Adult approach

Adult zebrafish are fed a Control Diet (CD) versus a HFC diet for 8 weeks in the desired genetic background. Lipid staining is then performed to quantify the liver fat accumulation of zebrafish larvae.

Readouts

  • Hepatic steatosis: fat accumulation in the liver.

Advantages of NAFLD model performed in larvae, juvenile, and adult fish:

References

  1. Asaoka Y, Terai S, Sakaida I, Nishina H. The expanding role of fish models in understanding non-alcoholic fatty liver disease. Dis Model Mech. 2013 Jul;6(4):905-14. Epub 2013 May 29. Erratum in: Dis Model Mech. 2014 Mar;7(3):409.
  2. Godoy-Matos AF, Silva Júnior WS, Valerio CM. NAFLD as a continuum: from obesity to metabolic syndrome and diabetes. Diabetol Metab Syndr. 2020 Jul 14;12:60.