Milk thistle extract (silbinin) works effectively to alleviate symptoms of Cushing Disease (caused by a tumor in the pituitary gland in the brain), according to new comprehensive research from the Max Planck Institute. The research included work done using cell cultures, animal models, and also human tumor tissue.

The treatment appears to be so effective that the researchers involved in this work think that it may allow some patients to avoid brain surgery completely — an ideal outcome as far as treatment of Cushing Disease (which is not Cushing’s Syndrome it should be noted) goes.

In Cushing Disease, a brain tumor in the pituitary gland causes the secretion of increased levels of the stress hormone adrenocorticotropin (ACTH), which triggers the release of the stress hormone cortisol from the adrenal glands — which leads to fat gain, muscular weakness, elevated blood pressure, and diminished testosterone levels, amongst other things.

Patients with the disease are highly prone to microbial infections, depression, osteoporosis, and may show cognitive deficiencies. Standard treatment for severe case currently is brain surgery — which in 80-85% of cases results in the tumor being removed. Inoperable cases exist though — and as it stands are treated with a regimen that is accompanied by severe side effects.

Effective treatment via simpler, cheaper, and safer, compounds such as silbinin (milk thistle extract) would be of great use.

“Silibinin is the major active constituent of milk thistle seeds. It has an outstanding safety profile in humans and is already used for the treatment of liver disease and poisoning,” stated Marcelo Paez-Pereda, lead researcher behind the new study. (See: Milk Thistle (Silybum marianum) Benefits, Side Effects, & Silymarin Uses + Research Findings)

The research found that with silibinin treatment, tumour cells reverted to normal ACTH production, tumor growth slowed down considerably, and “symptoms of Cushing Disease disappeared in mice”.





A recent press release provides further information:

In 2013, the Max Planck scientists filed a patent on a broad family of chemical and natural compounds, including silibinin, to treat pituitary tumours. Compared to humans, of which only 5.5 in 100,000 people worldwide develop Cushing Disease, this condition is very common in several pets. For example, 4 % of dogs and even 7 % of horses suffer from Cushing Disease. Thus, the researchers now plan to test special formulations with a very pure substance and slow release of the active component silibinin in clinical trials.

In their first experiments the researchers found tremendously high amounts of the heat shock protein 90 (HSP90) in tumour tissue from patients with Cushing Disease. In normal amounts HSP90 helps to correctly fold another protein, the glucocorticoid receptor which in turn inhibits the production of ACTH.

“We knew that Cushing Disease is caused by the release of too much ACTH. So we asked ourselves what causes this over production and how to stop it.”

“As there are too many HSP90 molecules in the tumor tissue, they stick to the glucocorticoid receptor,” explained Paez-Pereda. “We found that silibinin binds to HSP90 thus allowing glucocorticoid receptor molecules to dissolve from HSP90. With silibinin we might have discovered a non-invasive treatment strategy not only for the rare Cushing Disease but also for other conditions with the involvement of glucocorticoid receptors such as lung tumors, acute lymphoblastic leukemia or multiple myeloma.”

The new findings are detailed in a paper published in the journal Nature Medicine.

Image Credit: Curtis Clark