The Little Pig Goes To Market

Selecting extracts from swine brains to treat neurodegenerative diseases and more

by Simon Grose

Researchers at New Zealand’s Living Cell Technologies (LCT) are turning a legacy of 19th-century whaling into a tool of modern biotechnology. Whalers took pigs to Auckland Island in the Southern Ocean as a source of food, but after they stopped visiting the island the pigs remained there and survived. Their isolation from many diseases makes tissue from these pigs ideal for therapeutic transplantation into other species, known as xenotransplantation. In the 1990s, LCT began breeding from this stock, raising many generations in hygienic conditions on a diet free of animal products.

In its search for a xenotransplantation treatment for neurological diseases like Parkinson’s and Huntington’s, LCT focuses on the choroid plexus, which lies in the ventricles—or fluid-filled structures—inside the brain. Taking this tissue from pigs a few days after birth, the researchers use a membrane of alginate gum derived from seaweed to encapsulate clusters of 50–300 swine cells. Micropores in the membrane block immune-system warriors that might enter the cell cluster from a transplant host, which eliminates the need for anti-rejection medication. But nutrients are small enough to enter, and growth factors and other compounds made by the pig cells are small enough to exit.

LCT first applied this system to treat diabetes. Several human subjects have benefited from implants of encapsulated porcine pancreatic islet cells, which remained viable for periods of years and have reduced or eliminated the need for insulin medication.
Paul Tan, the company’s managing director, says they hope to use the choroid-plexus approach to treat neurodegenerative disorders. “We are not implanting cells to replace cells that have been lost,” Tan says, “we are implanting cells to produce various neurotrophins, growth hormones and support factors with the intention of protecting existing cells from further degeneration due to toxicity, damage or injury and encouraging the spontaneous repair of the brain.”

“ ... turning a legacy of 19th-century whaling into a tool of modern biotechnology. ”

In the December 2009 Journal of Neural Engineering, the company’s researchers reported that implants in the brains of rats released neuroprotective agents and remained viable after six months. Having gained a European patent for the technology in January, LCT plans to move to primate trials this year.

Another potential application of the outputs of choroid plexus cells is being investigated by Rhode Island start-up CytoSolv. In February, CytoSolv and LCT signed a deal under which CytoSolv will be supplied with choroid plexus–cell clusters and licensed to use LCT’s patents for the purpose of wound healing. CytoSolv has demonstrated that a topical gel based on the outputs of choroid plexus cells enhances healing of open skin wounds.

So, more than a century after their ancestors provided bacon for lonely whalers, LCT’s pigs might provide new treatments for diseases and other health challenges faced by people throughout the world.