Chopstick Accident Leads to Stem Cell Breakthrough

Remember that scene in 'Karate Kid' when Daniel-San walked in on Mr. Miyagi trying to catch a fly with a pair of chopsticks? In response to Daniel-San asking what the heck he was doing, Mr. Miyagi replied cryptically, "He who catch fly with chopstick can do anything." (Or something like that.) Oh, Mr. Miyagi's wise wise words have proven true in yet another instance.

Reported in this week's Economist (hat tip Bob Abu for the scan), is fascinating story of science meets serendipity. A Chinese woman was admitted to Huashan Hospital in Shanghai, with a chopstick in her brain (!)---specifically the inferior prefrontal subcortex. The chopstick was removed by a Dr. Zu, who took the opportunity to culture the brain tissue that came out with the chopstick. He wanted to verify whether there existed adult neural stem cells there.

The cultured tissue thrived, and many of the resultant cells contained proteins that were characteristic of neural stem cells. In order to make sure they were really stem cells, Dr. Zu cultured cells in isolation and watch and see if it divides into daughter cells. He found that about 4% of the 'chopstick cells' went on to form neurospheres (a ball of daughter cells), indicating that they were stem cells. Inspired, Dr. Zu began collecting tissue for various other patients who had suffered traumatic brain injuries and tried to derive neural stem cells from them as well. 16 out of 22 patients successfully yielded stem cells; tissue from the inferior prefrontal subcortex (the chopstick injured area) seem to be the best source. (Continued under the fold......)

The next question was whether the brain-derived neural stem cells could be used therapeutically. Stem cells derived from a person's own body would not face the threat of being rejected by the immune system. Dr. Zu first conducted the study in mice who were immuno-suppressed. He injected human neural stem cells cultured from his patients into mouse brains, and discovered that they successfully differentiated into the right kinds of cells in the brain. Also, the nerve cells were functional--they were able to form synapses and conduct electrical impulses.

Next was injured mouse brains. The purpose here was to determine if the cultured stem cells could "track" to the site of injury and repair the damage. In order to track the injected cells, Dr. Zu's lab attached magnetic particles to them and injected them with a dye. Following injection, they observed that the cultured cells did move to the injured area (they had induced a stoke in these mice.) The last animal trial was in monkeys, to test the safety of the therapy in an animal model similar to people. It was important to verify that the therapy did not cause cancer or any other nasty side effect. No cancer or warning signs were seen.

Finally, people! They transplanted cultured neural stem cells derived from 8 patients with brain injuries back into those same patients' brains. They then asked a separate group of neurologists to blindly examine these experimental patients and compare them with un-treated control patients who also had similar injuries. The treated patients had lower disability scores (a good thing), possibly paving the way for this therapy to be used clinically. And all because of one mis-aimed chopstick!