Nanoparticles Get Lymphatic Vessels Pumping

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Researchers at the Georgia Institute of Technology have developed a nanotechnological solution for lymphedema, a failure of the lymphatic system that results in uncomfortable and irreversible fluid retention. Previous research efforts have focused on trying to grow new lymphatic vessels, but these researchers have taken a different approach, and instead engineered a drug delivery technology that can directly target sluggish lymphatic vessels and kickstart their pumping action.

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To achieve this, the researchers used a drug that has been used to target calcium channels to enable muscle contraction in cardiac and skeletal muscles. They encapsulated the drug compound into nanoparticles that were designed to accumulate in lymphatic vessels and then release the drug in a localized manner. So far, the approach seems to help kickstart the vessels into doing their job in moving fluid.

Lymphatic vessels can become damaged through injury, or in some cases from the side-effects of cancer therapy or surgery. This impairment can result in localized fluid retention that is uncomfortable and can be difficult to treat. Previously, researchers have focused on trying to regrow new lymph vessels, but this latest research showcases a simpler approach and instead focuses on improving the action of the existing vessels.

“With many patients, the challenge is that the lymphatic vessels that still exist in the patient aren’t working. So it’s not that you need to grow new vessels that you can think of as tubes, it’s that you need to get the tubes to work, which for lymphatic vessels means to pump,” said Brandon Dixon, a researcher involved in the study. “That’s where our approach is really different. It delivers a drug to help lymphatic vessels pump using a nanoparticle that can drain into the diseased vessels themselves.”

So, why can’t a patient simply take the drug orally or intravenously? Well, the compound, called S-(-)-Bay K8644, targets calcium channels that are involved in muscle contraction in endocrine, cardiac, or skeletal tissues. Allowing the drug to spread unchecked throughout the body could lead to a host of unpleasant side-effects including convulsions.

To address this, the researchers encapsulated the compound into nanoparticles that are designed to accumulate in the lymph system and then release the drug gradually, precisely where it is needed. “Lymphatic tissues work like river basins — regionally you have vessels that drain the fluid out of your tissues,” said Susan Thomas, another researcher involved in the study. “This method is like putting nanoparticles in the river to help the river flow better.”

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