MIT researchers can release hormones like adrenaline and cortisol from the adrenal gland by using magnetic nanoparticles. These hormones are linked to a variety of mental health disorders, including depression and posttraumatic stress disorder (PTSD). Learning to control these hormones remotely can lead to treatments for these hormone-linked mental health disorders. The study was published in the journal Science Advances.
Magnetic Nanoparticles
In the study, the researchers used specialized magnetic nanoparticles they developed that can be injected into the adrenal gland. When these particles are exposed to a weak magnetic field, they heat up slightly and activate heat-responsive channels, which in turn trigger hormone release. The advantage of this technique is that organs deep in the body can be stimulated to release hormones with minimal invasiveness.
The adrenal gland is part of what is called the hypothalamic-pituitary-adrenal (HPA) axis, which regulates stress response in mammals. It secretes hormones like cortisol and adrenaline which play important roles in depression, stress, and anxiety.
Calcium Ion Channels
There are calcium ion channels in glands like the adrenal. These channels can be activated by many stimuli including heat. When calcium flows through the open channels into adrenal cells, the cells begin pumping out hormones. By remotely modulating these calcium ion channels, the hormones can be released by remote control.
Using Heat to Stimulate Hormone Release
The researchers used what is called magnetothermal stimulation. They injected nanoparticles made of magnetite into adrenal glands of rats. Magnetite is a type of iron oxide that forms tiny magnetic crystals about 1/5000 the thickness of a human hair. The nanoparticles can remain in the adrenal gland up to six months. The rats were then exposed to a weak magnetic field, causing the nanoparticles to heat up by six degrees Celsius. This heat is enough to trigger the calcium channels to open while not damaging the surrounding tissues. Once the channels are opened, the calcium ions flow and the hormones are released.
The researchers found that the stimulation resulted in a hormone rush. It doubled the cortisol production and boosted noradrenaline by about 25 percent. This also led to a measurable increase in the heart rates of the rats.
Potential Treatment for Mental Disorders and Pain
This approach can be potentially applied to develop new treatment for hormone-linked mental health disorders like depression and PTSD. In addition, this method can also be applied to look at treating pain. Heat-sensitive ion channels are often found in pain receptors.
“Being able to modulate pain receptors with this technique potentially will allow us to study pain, control pain, and have some clinical applications in the future, which hopefully may offer an alternative to medications or implants for chronic pain,” said Polina Anikeeva, one of the study’s senior authors.
Future Applications
Using magnetic nanoparticles to remotely release hormones in organs deep in the body, while requiring only minimal invasiveness hold much promise. Hopefully, this strategy can help develop new treatments for hormone-linked mental health disorders and relieving pain.
