Engineered Organs: Breakthroughs Breaching the Frontiers of Medical Science?
Hey there! Let's dive into the buzzing world of tissue engineering, primarily focusing on its potential impact on gastrointestinal problems, like short bowel syndrome and fecal incontinence.
Tissue engineering is an innovative concept that aims to grow patients' stem cells in labs, then combine them with scaffold materials to create laboratory-grown organs. However, waiting rooms haven't seen many benefits from this technology yet. Could that be about to change?
Gastrointestinal issues are no laughing matter, and current medical treatments are far from perfect. Take, for example, short bowel syndrome, which affects roughly 25 out of every 100,000 newborns in the United States each year. Babies born with this condition may have a short intestine that can't absorb nutrients properly, leading to lifelong complications. Additionally, it can develop later in life after part of the intestine needs to be removed due to cancer or other diseases.
Another common problem is fecal incontinence, which can occur when the anal sphincter is damaged during childbirth, childbirth-related cancer surgery, or as part of the aging process. According to statistics, as many as 26 percent of women experience fecal incontinence following vaginal birth.
To tackle these problems head-on, a team from the Wake Forest Institute for Regenerative Medicine in Winston Salem, NC, has been tirelessly working on developing new therapies for anal sphincter injuries and short bowel syndrome.
But what are the odds of these new therapies actually reaching the patients who desperately need them?
Tissue-Engineered Bowel
Professor Khalil N. Bitar, a regenerative medicine expert, explains the team's approach: "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 complex tissue made up of muscle cells that propel food through the gut and are connected to nerves to stimulate contractions. However, one of the greatest challenges in tissue engineering is getting different cell types to work closely together, as they naturally do in the body.
Dr. Bitar's team has taken years to develop a precise technique that allows them to grow muscle cells that align precisely and connect with nerve cells. In a recent study published in Tissue Engineering Part C: Methods, they transferred sheets of both cell types to small hollow tubes, mimicking the structure of the small intestine. These tubes were then implanted into rats to see how well they would work.
After 4 weeks, blood vessels had infiltrated the tubes, and after 6 weeks, food was found inside the tubes, indicating that digestion occurred, and food was actively moving 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," says Dr. Bitar. "Our results suggest that engineered human intestine could provide a viable treatment to lengthen the gut for patients with gastrointestinal disorders, or patients who lose parts of their intestines due to cancer."
Looking ahead, the team plans to test the tubes in a larger animal model.
The Latest Breakthrough: Engineered Anal Sphincter
In a separate study published in Stem Cells Translational Medicine, the same team demonstrated the feasibility of using an engineered anal sphincter in a large animal model to restore fecal continence, following more than ten years of research.
Combining muscle and nerve cells to create a ring-like structure, they then transplanted this engineered sphincter into rabbits with fecal incontinence. After three months, the results showed that the engineered sphincters were functional, with both muscle and nerves present, and fecal continence was restored in rabbits receiving the transplant. Longer follow-up studies are currently taking place.
Researchers are not the only ones working on tissue-engineered solutions in this field of research.
Cells and Scaffolds
Another approach involves combining cells from the intestine with a tubular scaffold structure, which includes epithelial cells, as demonstrated by Tracy Grikscheit, M.D., an associate professor of surgery and research investigator at the Saban Research Institute at Children's Hospital Los Angeles in California.
James Dunn, M.D., a professor of surgery and bioengineering at the Stanford School of Medicine in California, and his team have developed a rapid expansion of intestinal stem cells for treating different intestinal problems.
Levilester Salcedo, M.D., and Massarat Zutshi, M.D., from the Department of Colorectal Surgery at the Cleveland Clinic in Ohio, showed improvements in anal sphincter function after removing 25 percent of the sphincter in a rat model using bone marrow stem cell injections.
The bottom line? Progress is being made in tissue engineering of the gastrointestinal tract, but it will likely be years before patients see the benefits. Dr. Dunn explains that the biggest barrier is "to get all of the cell types working together in a coordinated fashion, followed by scaling the tissue-engineered intestine to [a] clinically useful dimension."
In fact, most areas of tissue engineering suffer from the problem of scaling. If therapies work well on the scale of small rodents, making much larger constructs for humans is much more challenging.
So, while the future of tissue-engineered bowel treatments looks promising, it's unclear when they'll become a reality for patients. However, one thing is certain: we need pioneering scientists to continue searching for novel treatments, and research funding is key to making this a reality.
Tissue-engineered bowel solutions show promising results in addressing complex gastrointestinal disorders, such as short bowel syndrome and fecal incontinence, contributing significantly to patient care in health-and-wellness and medical-conditions management. For instance, Dr. Bitar's team at Wake Forest Institute for Regenerative Medicine has successfully grown muscle and nerve cells to form small intestine-like structures, demonstrating the potential for laboratory-grown organs to revolutionize the science of treating gastrointestinal medical-conditions.
