Regenerative medicine is defined as a branch of translational research in tissue engineering and molecular biology which deals with the "process of replacing, engineering or regenerating human cells, tissues or organs to restore or establish normal function". Printing whole new organs for transplants sounds like something out of a sci-fi movie, but the real-life budding technology could one day make actual kidneys, livers, hearts and other organs for patients who desperately need them. In the ACS journal Langmuir , scientists are reporting new understanding about the dynamics of 3-D bioprinting that takes them a step closer to realizing their goal of making working tissues and organs on-demand.
Regenerative medicine also empowers scientists to grow tissues and organs in the laboratory and safely implant them when the body cannot heal itself. Importantly, regenerative medicine has the potential to solve the problem of the shortage of organs available for donation compared to the number of patients that require life-saving organ transplantation, as well as solve the problem of organ transplant rejection, since the organ's cells will match that of the patient. This field holds great promise of engineering damaged tissues and organs via stimulating the body's own repair mechanisms to functionally heal previously irreparable tissues or organs.
The definition of a stem cell - An undifferentiated cell whose daughter cells may differentiate into other cell types, such as blood cells. After twenty years of research, there are currently no approved treatments or human trials using embryonic stem cells. Stem cells in general term refers to the fertilized human embryo that has an ability to develop into any other 220 types of cells present in an adult human body.
Stem cells can now be grown and transformed into specialized cells with characteristics consistent with cells of various tissues such as muscles or nerves through cell culture. Highly plastic adult stem cells from a variety of sources, including umbilical cord blood and bone marrow, are routinely used in medical therapies. Embryonic cell lines and autologous embryonic stem cells generated through therapeutic cloning have also been proposed as promising candidates for future therapies.
Stem cells are cells found in most, if not all, multi-cellular organisms. They are characterized by the ability to renew themselves through mitotic cell division and differentiating into a diverse range of specialized cell types.
The two broad categories of mammalian stem cells are embryonic stem cells, derived from blastocysts, and adult stem cells which are found in adult tissues. The term adult stem cell refers to any cell which is found in a developed organism that has two properties: the ability to divide and create another cell like itself and also divide and create a cell more differentiated than itself.
The term cord blood is used for blood that is drawn from the umbilical cord and the placenta after a baby is born. Up until recently this afterbirth was discarded as medical waste. Cord blood contains stem cells which may be frozen for later use in medical therapies, such as stem cell transplantation or regenerative medicine. Because a person's own (autologous) cord blood stem cells can be safely infused back into that individual without being rejected by the body's immune system, and because they have unique characteristics compared to other sources of stem cells, they are an increasing focus of regenerative medicine research. The use of cord blood stem cells in treating conditions such as brain injury and Type 1 Diabetes is already being studied in humans, and earlier stage research is being conducted for treatments of stroke, and hearing loss.
Embryonic stem cell lines are cultures of cells derived from the epiblast tissue of the inner cell mass (ICM) of a blastocyst or earlier morula stage embryos. A blastocyst is an early stage embryo, approximately four to five days old in humans and consisting of 50 - 150 cells.
ES cells are pluripotent and give rise during development to all derivatives of the three primary germ layers:
In other words, they can develop into each of the more than 200 cell types of the adult body when given sufficient and necessary stimulation for a specific cell type. They do not contribute to the extra-embryonic membranes or the placenta.
Adult stem cell refers to any cell which is found in a developed organism that has two properties: the ability to divide and create another cell like itself and also divide and create a cell more differentiated than itself. Also known as somatic stem cells and germline stem cells, they can be found in children, as well as adults. Pluripotent adult stem cells are rare and generally small in number but can be found in a number of tissues including umbilical cord blood. A great deal of adult stem cell research has focused on clarifying their capacity to divide or self-renew indefinitely and their differentiation potential.
There is also another from of stem cell capable of generating specific types of new cells that are required for someone suffering from any cell degeneration disease. While adult stem cells hardly raise any controversial issues the former cells obtained from fertilized human embryo is a topic for hot debate among people with different mind sets.
While the possible treatment by stem cells has been good news, its origin from a fertilized human embryo has led to hot debates. A fertilized embryo is often referred to as a living being and harvesting it for the purpose of medicinal use leads to an end of embryonic life. Hence it raises a question of ethics that should one life be sacrificed for saving another.
People in the field of medical advancements strongly support research based on stem cell theory. Stem cell advancement has been a light of hope for people suffering from diseases that were supposed to be incurable until now. Medical scientists have done experiments to establish the fact that fertilized embryos of human origin can be used for successful treatment of diseases in which the present damaged cells in any person's body were incapable of regenerating themselves.
Many people especially certain religious organizations and the catholics stand very opposed to this form of medical research and have boycotted it since it's beginning. Those who are in favor of rearing stem cells say that such research is carried on embryos that were never meant to develop into humans.
A number of adult stem cell therapies already exist, particularly bone marrow transplants that are used to treat leukemia. In the future, medical researchers anticipate being able to use technologies derived from stem cell research to treat a wider variety of diseases including cancer, Parkinson's disease, spinal cord injuries, Amyotrophic lateral sclerosis and muscle damage, amongst a number of other impairments and conditions. Medical researchers believe that stem cell therapy has the potential to dramatically change the treatment of human disease.
As we age, stem cells throughout our bodies gradually lose their capacity to repair damage, even from normal wear and tear. Researchers from the Ottawa Hospital Research Institute and University of Ottawa discovered the reason why this decline occurs in our skeletal muscle. The team found that as muscle stem cells age, their reduced function is a result of a progressive increase in the activation of a specific signaling pathway. Such pathways transmit information to a cell from the surrounding tissue. The particular culprit identified by Dr. Rudnicki and his team is called the JAK/STAT signaling pathway. When we used specific drugs to inhibit the JAK/STAT pathway, the muscle stem cells in old animals behaved the same as those found in young animals. These inhibitors increased the older animals ability to repair injured muscle and to build new tissue. As we get older, the activity of the JAK/STAT pathway shoots up and this changes how muscle stem cells divide. To maintain a population of these stem cells, which are called satellite cells, some have to stay as stem cells when they divide. With increased activity of the JAK/STAT pathway, fewer divide to produce two satellite cells (symmetric division) and more commit to cells that eventually become muscle fiber. This reduces the population of these regenerating satellite cells, which results in a reduced capacity to repair and rebuild muscle tissue. While this discovery is still at early stages, Dr. Rudnicki's team is exploring the therapeutic possibilities of drugs to treat muscle-wasting diseases such as muscular dystrophy. The drugs used in this study are commonly used for chemotherapy, so Dr. Rudnicki is now looking for less toxic molecules that would have the same effect. The full article titled "Inhibition of JAK/STAT signaling stimulates adult satellite cell function " was published online September 7, 2014, by Nature Medicine .