The concept behind tissue engineering is simple: grow the patient’s stem cells in the laboratory, add them to a scaffold material, and you have a laboratory-grown organ. But few patients have benefited from this technology so far. Could change be on the horizon?
Scientific studies are frequently hailed as bringing novel, breakthrough treatments to patients. But the stark reality is that a long road must be travelled to turn a discovery in the laboratory into a viable clinical option.
For patients with severe gastrointestinal problems, new solutions are sorely needed; current medical treatments are marred with problems.
And complications such as this affect many people. For instance, babies with short bowel syndrome have a small intestine that is too short, making it unable to absorb nutrients properly. This condition affects around 25 in 100,000 newborns per year in the United States and can leave them with lifelong complications.
Short bowel syndrome can also occur when part of the intestine has to be removed due to cancer or other diseases.
Also, when the anal sphincter becomes damaged during childbirth – as a result of either cancer surgery or old age – patients can experience fecal incontinence. As many as 26 percent of women are
To address these problems, a research team from the Wake Forest Institute for Regenerative Medicine in Winston Salem, NC, has been developing new therapies for both anal sphincter injuries and short bowel syndrome.
But what is the likelihood of these new therapies ever reaching the patients, many of whom are in desperate need of better treatment options?
Khalil N. Bitar, Ph.D., a professor of regenerative medicine, explains the team’s approach, saying, “Our goal is to use a patient’s own cells to engineer replacement tissue in the lab for devastating conditions that affect the digestive tract.”
The small intestine is a complicated tissue. It consists of muscle cells that are essential for the contraction and forward propulsion of the food, as it moves through the gut. These cells must be aligned in a precise way to allow contraction to happen. Nerves are essential to stimulate the muscle cells to contract.
Similarly, in the sphincter, both muscle and nerve cells need to work closely together for normal function. This co-operation between different cells is one of the biggest challenges in tissue engineering. Although cells naturally grow and work together in the body, different cells are mostly grown in isolation in the laboratory.
Dr. Bitar’s team has spent years developing a precise method that allows them to grow muscle cells that are precisely aligned in one direction, and connect with nerve cells when they are added to the cell culture a few days later.
In a recent paper in published in Tissue Engineering Part C: Methods, the researchers transferred sheets of both cell types to small hollow tubes, which would make up the structure of the small intestine.
The tubes were then implanted into the lower abdomen of rats for 4 weeks, to allow blood vessels to infiltrate the structure. After this acclimatization phase, the tubes were attached to the small intestine of the rats, where they stayed in place for 6 weeks.
Importantly, the researchers found that after this period, the cells of the lining of the gut, or epithelial cells – which are essential for nutrient uptake from food – had started to migrate into the tube.
They also found food in the tubes, indicating that digestion was taking place and that this food was actively being moved through the tubes.
“A major challenge in building replacement intestine tissue in the lab is that it is the combination of smooth muscle and nerve cells in gut tissue that moves digested food material through the gastrointestinal tract,” Dr. Bitar explains.
Source: Medical News Today
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