From the Guidelines
PPAR agonists, specifically pioglitazone, can be considered as a treatment option for nonalcoholic steatohepatitis (NASH) diagnosed by liver biopsy in patients with or without diabetes mellitus, due to its ability to improve insulin sensitivity and reduce liver fat and inflammation. The most recent and highest quality study, 1, published in 2021, demonstrates that pioglitazone reduces insulin resistance in the liver, muscle, and adipose tissue, and also reduces the amount of fat in the liver and hepatocellular injury.
Some key points to consider when using pioglitazone for NASH include:
- Typical dosing is 30-45 mg/day
- Pioglitazone has been shown to improve histologic features of NASH, including steatosis, lobular inflammation, and hepatocellular ballooning
- However, pioglitazone may not improve liver fibrosis, a major indicator predicting the progression of liver disease
- Common side effects of pioglitazone include weight gain, fluid retention, and potential cardiovascular concerns
- Regular monitoring of liver function, kidney function, and lipid/glucose levels is essential when using pioglitazone
It's also important to note that other studies, such as 1 and 1, have also demonstrated the efficacy of pioglitazone in improving NASH, but the most recent and highest quality study, 1, provides the strongest evidence for its use. Additionally, an older study, 1, highlights the importance of monitoring for fluid retention and congestive heart failure when using thiazolidinediones, including pioglitazone.
From the FDA Drug Label
Pioglitazone is a potent agonist for peroxisome proliferator-activated receptor-gamma (PPARγ). The active moiety of fenofibrate tablet is fenofibric acid. The pharmacological effects of fenofibric acid in both animals and humans have been extensively studied through oral administration of fenofibrate The lipid-modifying effects of fenofibric acid seen in clinical practice have been explained in vivo in transgenic mice and in vitro in human hepatocyte cultures by the activation of peroxisome proliferator activated receptor α (PPARα)
From the Research
PPAR Agonist Overview
- PPAR agonists are a class of drugs that activate peroxisome proliferator-activated receptors, which play a crucial role in regulating metabolic functions and reducing cardiovascular risk factors associated with type 2 diabetes mellitus 4.
- PPARgamma agonists, such as thiazolidinediones, act as insulin sensitizers and improve insulin resistance in patients with type 2 diabetes 4, 5.
Clinical Applications
- Pioglitazone, a PPAR-gamma agonist, has been shown to be effective in reducing insulin resistance and improving glycemic control in patients with type 2 diabetes, with a low incidence of side effects 6.
- PPAR-alpha agonists, such as fibrates, can correct dyslipidemia and improve cardiovascular outcomes in patients with type 2 diabetes 4, 5.
- Dual PPAR-alpha/gamma agonists, such as aleglitazar, are being developed to manage glycaemic control and improve dyslipidaemia in patients with type 2 diabetes, with promising results in phase II clinical trials 5.
Cardiovascular Safety Considerations
- While PPAR-gamma agonists have been associated with an increased risk of heart failure, pioglitazone has been shown to reduce cardiovascular morbidity and mortality, whereas rosiglitazone may increase the risk of cardiovascular events 7.
- The use of PPAR-gamma agonists has also been linked to an increased risk of osteoporosis and bladder cancer, highlighting the need for careful consideration of the benefits and risks of these agents in the treatment of diabetes 7.
Mechanisms of Action
- PPAR-gamma agonists, such as pioglitazone, have been shown to reduce oxidative and endoplasmic reticulum stress associated with hypertension, highlighting a potential mechanism for their antihypertensive effects 8.
- Activation of PPAR-gamma by pioglitazone has also been shown to restore nitric oxide levels, increase endothelial NO synthase expression, and reduce endothelial dysfunction in hypertensive rats 8.