October 2017 Discover

October 2017^ DISCOVER^37

MARK RIGHTMIRE

across the street and navigate her

cozy art deco-style apartment with

surprising nonchalance. This year,

Macdonald received another stem

cell shot, this time in her right eye,

and she is hopeful her vision will

continue to improve. “This has

made my whole life brighter,” she

says, “and I mean that literally.”

For Henry Klassen, an oph-

thalmologist at the University of

California, Irvine, and the director

of the retinitis pigmentosa project,

the experiment is the fruition of a

dream he’s had since his student

days. While in graduate school in

the mid-1980s, he transplanted

retinal tissue into a newborn rat

with impaired vision. After the

rat grew to adulthood, he shined

a light over the graft site. The ani-

mal’s pupil constricted. “The first

time it happened, I almost fell off

my chair,” Klassen recalls. “The

only way the rat could see the light

was through the transplant.”

But it was another three decades

before Klassen — who has used

retinal progenitor cells to restore

vision in mice, cats, dogs and

pigs — could conduct human tri-

als involving retinitis pigmentosa.

While no one in the study has fully

regained sight, quite a few of them,

like Macdonald, have experienced

improvements in their visual acu-

ity. “Even if we could slow down

the progression and postpone it so

they never actually go completely

blind,” Klassen says, “that alone is

significant.”

RELIEF FOR STROKE PATIENTS

In recent years, stem cell research has made such dra-

matic leaps that what once seemed like science fiction

is becoming reality. In a paper published in June 2016,

Canadian scientists revealed that a combination of

chemotherapy, which wipes out the patient’s diseased

immune system, and stem cells, which regenerate the

immune system, halted or lessened symptoms of mul-

tiple sclerosis.

The trial, which began in 2001 and spanned 13

years, involved 24 people with a severe form of MS.

During that period, the positive results endured. One

patient, who could barely walk or feed herself before

treatment, has been symptom-free and now drives,

kayaks, dances and skis. Still, experts sounded a

cautionary note because the chemo can be toxic: One

patient died of liver failure, and a second had serious

liver complications.

In another paper published in June 2016, a Stanford

team led by Steinberg proclaimed that injecting adult

stem cells directly into the brains of 18 stroke patients

substantially restored motor function in many cases.

In the study, a small hole was drilled into the skull of

the patient, who was awake and under local anesthesia.

Stem cells were injected into regions bordering the

damaged brain area. Stroke recovery usually plateaus

after six months. After the experimental treatment, the

patients’ improvements in daily-activity skills contin-

ued for up to three years after their strokes.

One of the people in the study was a 71-year-old

woman, paralyzed on her left side. After the procedure,

she lifted her left arm at Steinberg’s instruction. “I was

astonished,” Steinberg recalls, sitting in his office at

Sonia Coontz of Long Beach, Calif., received stem cell treatment two years ago after

a severe stroke impacted movement in her right arm and leg and garbled her speech.