Lab-grown mini lungs successfully transplanted into mice
Date:
November 8, 2016
Source:
University of Michigan Health System
Summary:
Scientists can now grow 3-D models of lungs from stem cells, creating new ways to study respiratory diseases, report scientists.
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Jason Spence, Ph.D. has grown 3-D models of various organs from stem cells, creating new ways to study disease. (Stock image)
Researchers at the University of Michigan have transplanted lab-grown mini lungs into immunosuppressed mice where the structures were able to survive, grow and mature.
"In many ways, the transplanted mini lungs were indistinguishable from human adult tissue," says senior study author Jason Spence, Ph.D.,
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The researchers' previous study showed mini lungs grown in a dish consisted of structures that exemplified both the airways that move air in and out of the body, known as bronchi, and the small lung sacs called alveoli, which are critical to gas exchange during breathing.
But to overcome the immature and disorganized structure, the researchers attempted to transplant the miniature lungs into mice, an approach that has been widely adopted in the stem cell field. Several initial strategies to transplant the mini lungs into mice were unsuccessful.
Working with Lonnie Shea, Ph.D., professor of biomedical engineering at the University of Michigan, the team used a biodegradable scaffold, which had been developed for transplanting tissue into animals, to achieve successful transplantation of the mini lungs into mice.
The scaffold provided a stiff structure to help the airway reach maturity.
"In just eight weeks, the resulting transplanted tissue had impressive tube-shaped airway structures similar to the adult lung airways," says
Tissue engineering is an emerging interdisciplinary field that uses principles from engineering, biology and chemistry in an effort towards tissue regeneration. The main draw of tissue engineering is the regeneration of a patient’s own tissues and organs free from low biofunctionality and poor biocompatibility and serious immune rejection. As medical care continues to improve and life expectancy continues to grow, organ shortages become more problematic.(Manufacturing living things) According to organdonor.gov, a patient is added to the waiting list every 10 minutes and an average of 18 people die everyday waiting for an organ donation. The “nirvana” of tissue engineering is to replace the need for organ donation altogether. This could be achieved using scaffolding from
When the organs fail the only option is a transplant. With lungs there is only a 50% rate of a five year survival rate after a lung transplantation involving the end-stage respiratory disease. With such a drastic survival rate a study was completed to determine if patients could have a better outcome. This study was done to help determine effective methods to enhance lung transplants before surgery; the Doctors placed the recipients on bi-level positive airway pressure ventilation (BIPAP.) “BIPAP is a noninvasive mode of ventilation administered through a tight-fitting mask to assist spontaneously breathing patients”
Each bronchus then divides again forming the bronchial tubes. The bronchial tubes lead directly into the lungs where they divide into many smaller tubes which connect to tiny sacs called alveoli. The average adult's lungs contain about 600 million of these spongy, air-filled sacs that are surrounded by capillaries. The inhaled oxygen passes into the alveoli and then diffuses through the capillaries into the arterial blood. Meanwhile, the waste-rich blood from the veins releases its carbon dioxide into the alveoli. The carbon dioxide follows the same path out of the lungs when you exhale.
In November of 1998, a group of researchers announced that they had successfully isolated and grown a special kind of cell with the potential to develop into virtually any kind of human tissue. The scientists had made the discovery of embryonic stem cells. The discovery was considered to be an innovative
Small air sacks called alveoli are at the tips of the bronchioles. When air reaches them, the oxygen concentration is high, which causes diffusion into red blood cells travelling through pulmonary capillaries (7). The red blood cells then distribute the new oxygen to the rest of the body. When they reach the alveoli again, they exchange carbon dioxide (a form of cell waste) for new oxygen, and repeat the process. The carbon dioxide is moved through the bronchioles, bronchi, and trachea in the form of exhalation.
Adult stem cells have already proven to be successful in treating diseases and have helped hundreds of thousands of patients, and new clinical uses expand almost weekly. Adult stem cells can be obtained from cord blood, fat, neural tissue, muscle, bone marrow, placental and skin cells. Adult stem cells are increasingly being shown to have a similar and perhaps an identical capacity to become cells of other types. There is a possibility that adult stem cells may function more efficiently and more safely than embryonic cells. Treena Arinzeh, a young professor who last year won a Presidential Award, the nation's highest scientific honor, is bringing the promise of stem cell research one step closer to reality. Adult stem cells also have a unique trait that lends them their magic: Under the right conditions, or given the proper signals, they have the ability to turn into different cell types. Arinzeh is doing exactly that: developing signals, in the form of biomaterials, that will help adult stem cells turn into cells that, if injected into a diseased area of the human body, could regenerate damaged tissue. Her research has also led to two major stem-cell discoveries: One showing that stem cells, when mixed with biomaterials known as scaffolds, can help regenerate bone growth; and another proving that stem cells taken from one person can be successfully implanted into another. A list of conditions for which stem-cell treatment holds promise grows almost daily: It now
Stem cell research is the future of medical and biological research and remedies, and it is fascinating to watch the progression of this new and important science as it unfolds. These cells were discovered in mouse embryos in the 1980s, and are remarkable because of their potential to grow into a variety of different kinds of cells within a body. Common in fetuses, and more rare in adult animals of all kinds, stem cells can be manipulated in useful ways to repair many tissues, dividing limitlessly for therapeutic purposes. When a stem cell divides, each new cell has the potential either to remain a stem cell or to differentiate into more specialized tissue, such as nerve, pancreas, bone marrow, or unique blood components. Initially
Many scientists believe that embryonic stem cell (ESC) research is the key to curing diseases such as cancer and HIV. Stem cells are so important to biomedical research because they are primitive cells that are capable of replicating indefinitely producing a multitude of different types of cells. This means that one of these pre-determined cells has to potential of becoming any range of over two hundred tissues with epithelial cells to blood and
In the past, the only way to replace diminished cells, tissues, and organs was from organ transplantation. An organ donor was needed, and the tissues would be surgically removed from the donated body and placed into the recipient. Due to the current research being conducted, it is believed that tissue engineering and organ printing can contribute to the process of improving and saving lives.
The alveoli provide a large surface area in the lungs as they are very small, they are highly folded and there are a large amount of them in the lungs. In both the lungs of an adult there are around 300 million alveoli. If the alveoli were to be flattened out the surface area would be around 70 metres squared. The alveoli are well adapted as we require a lot of oxygen to respire at an efficient metabolic rate. This also means that we can transfer carbon dioxide out of our body at an efficient rate so a large amount doesn't stay in our blood as it is very harmful.
“Through the isolation and manipulation of cells, scientists are finding ways to identify young, regenerating ones that can be used to replace damaged of dead cells in diseased organs. This therapy is similar to the process of organ transplant, only the treatment consists of the transplantation of cells rather than organs. The cells that have shown by far the most promise of supplying diseased organs with healthy cells are called stem cells.” (Chapter Preface)
The respiratory system is the process responsible for the transportation and exchange of gases into and out of the human body. As we breath in, oxygen in the air containing oxygen is drawn into the lungs through a series of air pipes known as the airway and into the lungs. As air is drawn into the lungs and waste gas excreted, it passes through the airway, first through the mouth or nose and through the pharynx, larynx and windpipe – also known as the trachea. At this point it then enters the lungs through the bronchi before finally reaching the air sacs known as alveoli. Within the lungs, through a process known as diffusion, the oxygen is transferred to the blood stream through the alveoli (air ducts) where it is then transported inside
We could use some of the patents stem cells to create the lung. The stem cells can be used as building blocks and can be turned into the cells in the lung. Some strengths are that the side effects wouldn't be like chemo and radiation treatment. Another strength is that you're getting a brand new lung and not damaging your lungs to cure the cancer. A weakness is that not a lot of people will be able to get the 3d printed organ because the printer wont be in every hospital. Another weakness is that your body may reject the new lung.
When cell populations are used to form tissues and organs, proper 3D systems, with clinically relevant dimensions, are required to eventually scale up these findings into effective new treatments. 6
Healthy lung tissue is predominately soft, elastic connective tissue, designed to slide easily over the thorax with each breath. The lungs are covered with visceral pleura which glide fluidly over the parietal pleura of the thoracic cavity thanks to the serous secretion of pleural fluid (Marieb, 2006, p. 430). During inhalation, the lungs expand with air, similar to filling a balloon.