Scientists at the Fralin Biomedical Research Institute have started a new biotechnology company to apply one of nature’s courier systems to deliver a potentially life-saving medication.
The work, led by Virginia Tech professor Robert Gourdie, takes advantage of nanoscale bubbles called exosomes. But instead of shuttling biomolecules and genetic material throughout the body, these exosomes derived from cow’s milk will deliver a promising new drug to help patients after a damaging cardiac event.
In a study published in August in the Journal of the American Heart Association, Gourdie and colleagues showed that the alphaCT11 molecule had cardioprotective effects in mice, preventing the spread of cell death in heart muscle tissue – even when administered 20 minutes after a heart attack.
A challenge for realizing the potential of this therapeutic compound, however, is getting it to the stricken heart tissue intact.
“The drug appears to be very effective, but the next question we’re asking is what is the best way to guide this drug to target heart cells, while making it convenient for patients to ingest? That’s what my lab and Tiny Cargo are addressing,” Gourdie said.
Peptide drugs, such as alphaCT11, are tiny, fragile chains of amino acids that aren’t absorbed into the bloodstream if they don’t break down quickly in the stomach and small intestine. As a result, these types of drugs are often administered to patients via injections to overcome stability and absorption limitations.
Tiny Cargo’s nanosized technology seeks to overcome these challenges by using exosomes as delivery envelopes that patients can take by mouth instead.
Once regarded as fatty waste disposal containers secreted by cells, exosomes emerged as a potential drug delivery method in 2007 when Swedish researchers observed cells releasing exosomes containing genetic material used to regulate protein synthesis and gene expression in neighboring cells. Over the past decade, research into their function, transmission pathways, and the potential pharmaceutical applications has surged.
Some scientists are developing artificial capsules to mimic exosomes, while others, like Gourdie and his team, are finding answers in nature.
Milk generated by nursing mammals is packed with exosomes, apparently to deliver important nutrients, proteins, and other signaling molecules from the mother to the nursing baby. Researchers expect exosomes derived from mammalian milk will be more easily absorbed and tolerated by patients than synthetic substitutes.
“Pharmaceutical companies have not been keen to develop drugs based on peptides, even when they show great promise in animal studies, as they are difficult to administer to patients and break down quickly in the body,” Gourdie said. “Orally delivered exosomes from cow’s milk could provide a way to overcome both these barriers.”
Before it’s safe to proceed with clinical testing in humans, the scientists need to analyze the exosome’s stability and address potential immune reactions. Gourdie’s team is also analyzing ways to target exosome transfer so the medication-laden molecules are recognized and absorbed Gourdie and his team expect the alphaCT11 drug and Tiny Cargo’s exosome packaging could one day lead to better patient outcomes by limiting the spread of injury following a heart attack.
