There are thousands of people on the registry for a donor organ for various health reasons. It is reported that the most recent statistic is that around 121,678 people are waiting for their lifesaving organ transplant in the United States. The vast majority of these are patients needing a new kidney, an essential organ. Sure, we can live without one of them, but we must have at least one to filter our blood. According to the Kidney foundation, the median wait time for a patient’s kidney transplant is around 3.6 years. This varies depending on several factors including the severity of the case and compatibility of donor and recipient. Blood types must match. Many times, people must start drug therapy in order to prevent any rejections from the donor organ. Basically, the recipient’s body can see the donor’s organ as a foreign body and want to destroy it. This would pose obvious problems including the need for another transplant.
The Kidney Foundation stresses several eye-opening facts about just how prevalent the need for a new kidney is. It states that “over 3,000 new patient are added to the kidney waiting list each month” and “in 2014, 4,761 patients died while waiting for a kidney transplant”. Imagine the possibilities should most, if not all of these people, were able to receive their organ replacement due to new scientific discoveries of synthetic organs. In fact, this accomplishment has been made in several hollow organs (those that are have an opening in the center). Examples of hollow organs include the heart, trachea, blood vessels, and the urinary bladder. Unfortunately, there is not nearly as much progress on solid organs like the kidney. [before entering in details about scaffolds, you could have explained the very basics of synthetic organs - you need a frame and a filling, the scaffold is the frame and without telling the reader how it fits in the context of synthetic organs, all the following information gets very disconnected]
Wake Forest Institute for Regenerative Medicine has been able to do just that with rats (Eberli). They formed scaffolds (basic structures) in order to form these hollow synthetic organs. Researchers found that these scaffolding materials must be precisely measured for each organ. Since each organ has different functions, the needs of that organ must be met from these scaffolding materials. In hollow organs, this scaffolding system would act as a barrier between the hollow part of the organ and the outer layer. However, these two “layers” would be fused together so that they are working synchronously. A composite scaffolding system was formed by bonding collagen and polyglycolic acid (PGA) polymers together. PGA is a synthetic material that has been tested to make sure there is biocompatibility with human functions.
The way the scaffolding system works is by allowing regular tissue cells on one side of the system and the other serves as a barrier. For instance, the inner part of a urinary bladder would have the patient’s regular cells. These cells on the inner portion of the bladder would be able to develop and degrade normally which is also an essential aspect to research. We are constantly creating new cells and destroying the old ones, a process that needs to occur within these synthetic materials as well. The outer part of a urinary bladder would provide support to the organ and allowing it to function properly. [this paragraph should have been placed before the previous paragraph.]
Researchers have also been able to produce biologically-derived scaffolds that are made from natural human or animal tissues (Baiguera). In this process, they [use detergent solutions to remove the cells of the donor organ, a process called decellularization] decellularize the tissue by using a detergent. This method is similar to washing your clothes. Essentially, all of the donor’s cells are washed away, leaving only the protein and collagen that make up the visible structure of the organ. After doing this, the cells from the patient to whom the synthetic organ will be transplanted to are put in the scaffold and used to recellularize the tissue. This way, there is no rejection of tissue at all since the patient’s own cells are accepted by the immune system. The benefits of this approach include the fact that the scaffold retains the natural properties of the tissue. It has also been found that the tissue is flexible and in the same strength of the organ as before it went through this process of cellularization.
In order to keep the same biological functions of the organ, the organ must go in to a bioreactor. Since this scaffold never lost its biological aspects, it needs to maintain a similar environment as that of the human body. This is where the bioreactor comes in to play. For instance, in a bioreactor containing a biologically-derived heart, a pulsing flow of nutrients and electrical stimulation helps the heart to beat. This method of keeping the organ alive and functioning is not optimal, but works as an alternative for now. One of the main struggles scientists are having to resolve is getting the scaffold to become vascularized (have blood supply). As you can imagine, getting a synthetic tissue to have blood vessels can be a difficult task. A way that researchers could potentially solve this problem is by creating new blood vessels in order to manually vascularize the organ.
Many confuse these processes with stem-cell research. Stem-cells are not used in any of the techniques involved in tissue engineering. In fact, growing tissues and organs without this scaffold is considered regenerative medicine. Tissue engineering rebuilds tissue and restores function with scaffolds, cells, and growth factors. Regenerative medicine reconstructs tissue using gene transfer. The idea behind this type of medicine is the tissue will regrow itself with the correct environment. In tissue engineering, nothing is being grown; there is already a scaffold present with the general structure of the organ.
There are many advantages to synthetic organ development. Although research is still taking place, once the technology is developed, the price of transplant can drop enormously. The only cons of this scientific approach would be the possibility of the presence of latent or hidden diseases or illnesses in the synthetic tissue. This could possibly be determined once the tissue is placed in the recipient. The number of people on the waiting list for a transplant could potentially [drop to close to zero] be eradicated. Donor/recipient rejection could essentially be eliminated, cutting costs of pre and post-surgery care. Tissue engineering has the capability of prolonging lives and making the general quality much better. However, human clinical trials need to be endorsed in order for legislation to allow this technique to be used.
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