WEDNESDAY, May 11 (HealthDay News) -- Contrary to current
scientific thinking, human lungs do harbor stem cells capable of
forming different parts of the lung, including blood vessels, a new
The findings, reported May 12 in the
New England Journal of Medicine, may open the door to eventual bioengineered lung tissue repair and replacement.
"These cells are very smart. They know what to do," said study senior author Dr. Piero Anversa. "The clinical implications are significant."
The findings could potentially offer a new avenue of treatment
for patients suffering from respiratory conditions, such as
emphysema, chronic obstructive pulmonary disease or pulmonary
hypertension, that currently have only limited treatment
"Now that we have identified these cells and have the potential of growing them, we know it's not science fiction," said Dr. Andrew Pecora, vice president of cancer services and a stem cell expert with Hackensack University Medical Center in New Jersey. "A single cell placed in the right environment allows for the development of adult cells that can live for 80 years. The implications are potentially limitless."
Stem cells are those that first exist without organ-specific
features but are capable of dividing and morphing into every other
type of cell in the human body.
Stem cells are scattered throughout the body, and a growing
cadre of scientists is attempting to harness their innate abilities
to regenerate and repair parts of the human body, such as the
The new findings challenge conventional knowledge about lung
cells. According to an accompanying journal editorial, scientists
had been holding on to the belief that no single cell in the lung
could differentiate into multiple different types of cells, even
though some cells do grow into specific cells, such as endothelial
cells and the cells of the upper and lower airways.
For this trial, researchers were able to identify stem cells
from 21 samples of normal human lungs, then expand them in a test
The researchers coaxed the cells into developing into different
types of lung cells, such as epithelial or vascular cells.
They next injected undifferentiated cells into mice whose lungs
had been damaged.
"Over a period of about two weeks, we were able to regenerate a significant portion [of the lung] and essentially recreate various tissues," said Anversa, director of the Center for Regenerative Medicine at Brigham & Women's Hospital and Harvard Medical School in Boston. "The human structure was perfectly integrated with the structure of the mouse lung," he noted.
"The cells have the fundamental properties of stem cells," Anversa added. That means they could divide into new cells, form into many other types of cells and function when introduced into other environments.
But there's still a lot of work to be done before these cells
actually have any implications for humans, the editorial
Anversa will study the cells in larger animals before initiating
a phase I clinical trial.
"We're talking a few years from now," he said. "We're not talking about tomorrow morning."
The U.S. National Institutes of Health has more on