Lifesaving drug successfully lowers cholesterol levels and body weight

Rather than administering the hormone throughout the body, researchers designed nanogels to

More than 100 million Americans struggle with obesity and related metabolic disorders, a staggering number with widespread consequences.

More than 100 million Americans struggle with obesity and related metabolic disorders, a staggering number with widespread consequences. (CREDIT: iStock Images)

More than 100 million Americans struggle with obesity and related metabolic disorders, a staggering number with widespread consequences.

"We were really excited about this work," says S. Thai Thayumanavan, a biomedical engineer and chemist at the University of Massachusetts Amherst. This technique takes on greater significance when viewed against the broader health crisis.

At the heart of this breakthrough is a tiny yet powerful tool—nanogels. These microscopic carriers hold a synthetic thyroid hormone drug known as a thyromimetic. While thyroid hormones are vital for liver metabolism, their systemic use often leads to severe side effects, making them an unreliable treatment option.

Rather than administering the hormone throughout the body, researchers designed nanogels to deliver it precisely where it's needed.

A graphic depicting how the drug targets the liver. (CREDIT: Creative Commons)

"We came up with a very simple approach, using our unique invention—nanogels that we can direct selectively to different targets," Thayumanavan explains. "They were custom-designed for hepatocyte delivery in the liver." This precision avoids the harmful effects associated with traditional treatments.

The results were striking. Mice given the treatment lost all the excess weight they had gained, with no harmful side effects. "The treated mice completely lost their gained weight, and we did not see any untoward side effects," Thayumanavan reports.

But the benefits went beyond weight loss. Despite remaining on a high-fat diet, the mice showed improved cholesterol levels and significantly reduced liver inflammation. The findings suggest a deeper metabolic shift rather than just a temporary fix.

"We found that we are activating the reverse cholesterol transport pathway, which lowers cholesterol," Thayumanavan explains. This discovery points to a potential long-term solution for obesity-related conditions, offering hope for safer and more effective metabolic treatments.

He further theorizes, "We believe that activation of fat oxidation and an increase in metabolic rate are causing the loss in weight, but more work needs to be done to prove that point."

Delving into the mechanics, once these nanogels permeate the hepatocytes, the liver cell environment disintegrates the bonds within the nanogel, releasing axitirome. This drug subsequently latches onto proteins pivotal for gene expression regulation.

The apparent effectiveness of the ANG-delivered axitirome, which reversed weight gain without disrupting thyroid hormone levels, indicates a promising avenue for thyromimetics in addressing metabolic diseases like obesity.

A scanning electron micrograph of a section through a vein in the liver, showing red blood cells surrounded by hepatocytes (green). (CREDIT: PNAS Nexus)

An interesting observation emerged: mice on axitirome retained their appetite for high-calorie food. This is in stark contrast to human subjects using other weight loss drugs.

"There is a significant amount of development work to be conducted between mice and humans," Thayumanavan cautions, "but we are hoping it will eventually become a drug."

Driven by the promise of the nanogel technology his lab birthed, Thayumanavan has launched a startup, Cyta Therapeutics. Their primary mission? To spearhead cutting-edge delivery platforms ensuring drugs are dispatched to their intended bodily destinations.

In vivo lipid-regulating effects of CGS-ANG in GAN diet-induced disease model. A) Schematic illustration of protocol for fully developed disease establishment in C57BL/6J mice and therapeutic study of CGS-ANG. (CREDIT: PNAS Nexus)

The exciting potential of this discovery cannot be understated. It not only offers a beacon of hope for those grappling with obesity and associated disorders but also paves the way for further advancements in drug delivery, potentially revolutionizing the treatment of metabolic diseases.

Other Health Benefits for Thyromimetics

Thyromimetics are drugs that mimic the effects of thyroid hormones, primarily triiodothyronine (T3), by activating thyroid hormone receptors (THRs). They are being explored for various therapeutic applications due to their ability to regulate metabolism, cholesterol levels, and other physiological functions. Here are some potential benefits of taking thyromimetics:

Cholesterol Reduction and Cardiovascular Health

  • Some thyromimetics, such as Eprotirome and Resmetirom, selectively target thyroid hormone receptor beta (THR-β) in the liver. This activation helps:
    • Lower LDL (bad) cholesterol and triglycerides.
    • Increase HDL (good) cholesterol.
    • Reduce the risk of atherosclerosis and cardiovascular disease without significant side effects on the heart or bones.

Non-Alcoholic Fatty Liver Disease (NAFLD) and NASH Treatment

  • Thyromimetics like Resmetirom are being studied for their role in treating non-alcoholic steatohepatitis (NASH).
  • They help reduce hepatic fat accumulation, inflammation, and fibrosis by improving liver metabolism.

Potential for Hypothyroidism Treatment

  • Some thyromimetics are being investigated as alternatives or adjuncts to levothyroxine (T4) therapy in hypothyroid patients, particularly those who do not fully respond to T4 alone.

Neuroprotective Effects

  • Research suggests thyromimetics may play a role in protecting neurons and supporting brain health.
  • They are being explored for potential benefits in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s, by modulating brain metabolism.

Muscle and Bone Health

  • Thyroid hormones influence muscle strength and bone density.
  • Selective thyromimetics that avoid excessive THR-α activation (which can cause muscle breakdown and bone loss) may provide benefits for conditions like sarcopenia (age-related muscle loss).

Caution and Side Effects

While thyromimetics have promising benefits, excessive activation of thyroid receptors can cause tachycardia, muscle wasting, osteoporosis, and hyperthyroid-like symptoms.

The key is selectivity, with newer drugs targeting THR-β more than THR-α to avoid these side effects.

Thyromimetics are currently under investigation for their therapeutic potential, especially for cardiovascular and liver diseases.

Note: Materials provided above by the The Brighter Side of News. Content may be edited for style and length.


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Joseph Shavit
Joseph ShavitSpace, Technology and Medical News Writer
Joseph Shavit is the head science news writer with a passion for communicating complex scientific discoveries to a broad audience. With a strong background in both science, business, product management, media leadership and entrepreneurship, Joseph possesses the unique ability to bridge the gap between business and technology, making intricate scientific concepts accessible and engaging to readers of all backgrounds.