Stem cells are basically undifferentiated cells that mean they’re capable of developing into cells that perform various functions in different parts of the body. Mostly, cells in the body are differentiated cells. These cells can only perform a specific function in a particular organ. For example, red blood cells are involved explicitly in carrying oxygen through the blood. All humans born as only one cell called a zygote or a fertilized egg. The zygote then further divides into two cells, then four cells, and so on.
Later on, those cells begin to differentiate and perform certain functions in different parts of the body. This process is called differentiation. Stem cells are the ones who do not distinguish yet. They can divide and replicate. Some cells in the body can only replicate less before they start to break down entirely. When it finally cell divides can either remain the same convert into a differentiated cell.
Stem-cell therapy involves the use of stem cells to treat or prevent various types of severe diseases. Stem cells are being studied and used for several different reasons. The molecules released from stem cells are also being considered to take medications against various diseases. In addition to the functions of the stem cells, soluble paracrine factors produced by stem cells, have been in use in many other mechanisms by which stem cell-based therapies are used to treat autoimmune and inflammatory diseases.
Various types of stem cells have been used to treat different diseases for many years. Types of stem cells include embryonic stem cells, non-embryonic stem cells (adult stem cells), induced pluripotent stem cells, cord blood stem cells, and amniotic fluid stem cells.
Embryonic stem cells usually originated from human embryos that are three to five days old. They are collected from the process called in-vitro fertilization. It involves fertilizing a fetus in a laboratory instead of inside the female body. Embryonic stem cells are called pluripotent stem cells. These cells can give rise to many other types of cells in the body.
Adult stem cells are found mostly in infants and children. These stem cells come from various developed organs and tissues of the human body. Frequently, they’re used by our body to repair and replace damaged tissue in the same area in which they are present. They usually make new red blood cells, white blood cells, and other types of blood cells. Doctors have been performing stem cell transplantation or marrow transplantation for decades to treat certain types of cancer. Adult stem cells cannot differentiate into different kinds of cells.
Other new types of cells are called induced pluripotent stem cells (iPSCs). They can differentiate into different types of specialized cells within the body. This means that they can potentially produce a different kind of new cells for any organ or tissue. To create iPSCs, scientists are reprograming the adult stem cells so that they can behave like embryonic stem cells.
They are hoping that these cells can be made from patients’ own skin to treat their diseases. This will help to prevent the immune system from organ transplant rejection. Research is undergoing to find out different ways to produce iPSCs safely.
Another type of stem cell is cord blood stem cells that are collected from the umbilical cord after the childbirth. Then, they can be frozen in cell banks for use in the future. These cells are successfully used to treat children with blood cancers, such as leukemia, and certain genetic blood disorders. Amniotic fluid also contains stem cells in it. Amniotic fluid usually surrounds a developing baby inside the mother’s womb. However, more research is still needed to help scientists to understand the potential uses of amniotic fluid stem cells to treat various types of diseases.
Stem cells have been used to treat various diseases, including neurodegenerative disorders, brain, and spinal cord injury, heart disease, blood cancers, Blindness, vision impairment. They are also used to regenerate heart muscles and cells, pancreatic beta cells, for regrowing teeth and cochlear hair cell regrowth. And used to treat HIV/AIDS and infertility as well.
The following are the main breakthrough cures in stem cell research.
Adverse effects of stem cells on animal models
having Parkinson’s disease, Amyotrophic lateral sclerosis, and Alzheimer’s disease are observed. Studies also showed that they also play an essential role in treating multiple sclerosis. The healthy adult brain contains neural stem cells which generally divide to maintain stem-cell numbers, or become progenitor cells. In healthy animals, progenitor cells move within the brain and perform their specific functions for maintaining neuron populations for olfaction. Pharmacological activation of Endogenous neural has reported as an activater to neuroprotection and behavioral recovery in adult rat models with a neurological disorder.
Scientists are also using stem cells to create beating heart cells in-vitro for the first time. They are now working to grow a small piece of heart from stem cells could produce red blood cells for transfusion as well. It will help them to study various causes of diseases, especially genetic causes. And will also improve the development of medicines that are usually tested on animal models, whether their hearts work similarly or not. Researchers are also working to develop new treatments for the diseased heart.
In 2002, Chinese researchers found that human embryonic stem cells can be made to form heart muscle cells. This discovery helped scientists to find out whether embryonic stem cells could be used to create new heart muscle for heart attack patients or not. Embryonic stem cells have helped researchers explore new ways of using stem cells to fix our heart muscles.
Pluripotent Stem Cells (iPS)
Another breakthrough in stem-cell therapy was the ability to make induced pluripotent stem cells (iPS), which have properties similar to embryonic stem cells. In 2007, researchers found that human skin cells, which can easily be isolated and can be transformed directly into iPS cells. Scientists using iPS cells from the skin as a source to make new heart cells. They can also be used to study inherited heart conditions in various organisms. In the University of Nottingham, scientists are growing cells from patients to examine how genetic mutations affect heart cells’ differential behavior. Without stem cells, this work could only be done through a biopsy of the patient’s heart.
Researchers find out that tooth regeneration technology can be used to regrow live teeth in people. In this theory, stem cells are taken from the patients that are implanted in the gums and will give rise to a new tooth and would be grown in time over three weeks. It will mix with the jawbone and release various chemicals that help the nerves and blood vessels to connect with it. This process is quite to how humans grow their original adult teeth. Therefore, stem cells would be used for the replacement of missing teeth in the future.
- Type 1 diabetes patients lose their function of insulin-producing beta cells within the pancreas. In recent experiments, scientists have also been found that embryonic stem cells can regenerate into beta cells in the laboratory. In this theory, if the beta cell is transplanted successfully, then they will be able to replace malfunctioning beta cells in diabetic patients and will ultimately produce healthy insulin-producing beta cells.
- Human embryonic stem cells inactivated porcine ovarian fibroblasts (POF), which causes differentiation into germ cells. Human embryonic stem cells have widely been used to form Spermatozoon-like cells. This could be potentially used to treat azoospermia. In 2012, oogonial stem cells were first isolated from adult mouse and human ovaries and were capable of forming mature oocytes. So, these stem cells can treat infertility.
HIV-1/AIDS with Gene modification
Recently, scientists have been working to treat HIV-1/AIDS, through transplantation of gene-modified (HIV-1-resistant) hematopoietic stem and progenitor cells (GM-HSPC). Destruction of the immune system by the HIV will lead to loss of CD4+ T cells in the peripheral blood and lymphoid tissues. Viral entry into CD4+ cells occurred by interaction with a cellular chemokine receptor, the most common form of receptors is CCR5 and CXCR4. Because of viral replication, activated CD4+ cells are the primary targets of productive HIV infection. So, hematopoietic stem cells are used to treat HIV-1/AIDS.
Researchers are very hopeful that stem cells will one day be more effective in the treatment of many other medical conditions and diseases, even cancers. But stem cell treatments that are not clinically proved to be safe can’t be used, and scientists also have to consider all the facts when they are considering stem cells as the treatment of any disease.
Arooba Azeem is a student of BS biochemistry, Quaid e Azam University Islamabad. She is an active member of the management team(QDLs) of debating and literary societies of her University. Her particular hobbies are cooking and book reading.