In 1981, scientists discovered ways to derive embryonic stem cells from early mouse embryos. Since then, they have been the subject of intense scrutiny, controversy, and advocacy.

They are unique cells, which can be derived from human embryos and can be differentiated into virtually any kind of different cells. In humans, there are about 200 different types of cells including bone, muscle, and nerve cells, and within these cells there are about 20 different types of structures or organelles. Essentially, stem cells can be derived from human embryos, and with the right enzymes, can be stimulated. For instance, bone cells can originate from osteocyte cells, or liver tissues can come from hepatocytes.

Stem cell types and research

There are three types of stem cells:

• Embryonic stem cells
• Adult stem cells
• Induced Pluripotent Stem Cells (iPSC)

Embryonic stem cells are derived from human embryos. Adult stem cells are undifferentiated cells (meaning “clean slates” with the potential to change into another cell variant) found throughout the body after development; they multiply via cell division to replenish dying cells and regenerate damaged tissues. Induced Pluripotent Stem Cells (iPSC), which were discovered in 2006, are derived from skin or blood cells that have been reprogrammed back into an embryonic-like pluripotent state that enables the development of an unlimited source of any type of human cell needed for therapeutic purposes. While these types of cells are interesting and certainly worthy of research, this article will focus on embryonic stem cells as they are consistently the most well-known and discussed type by the general public.

Embryonic stem cells are potent and often sought after due to their abilities to proliferate without limit and contribute to any cell type. However, with great power comes great responsibility and stem cells are no exception. Poorly processed cells have been documented to mutate into cancerous tumors that can wreak havoc upon people’s bodies. Bearing this in mind, scientists also do not believe that this should derail stem cell therapies considering that there are DNA tests to check if stem cells will turn out to be problematic or not.

The stem cell project is regularly a subject of ethical debate in both the academic and public sectors. Most embryonic stem cells are derived from embryos that develop from eggs that have been fertilized in vitro—in an in vitro fertilization clinic—and then donated for research purposes with the informed consent of the donors. People willingly donate their eggs for this research, and this process does not constitute child-killing since the eggs are near their zygote phase, not a whole mature embryo. Scientists obtain those types of cells from an embryo which has not yet completed its formation to develop into a human being. Researchers then use these cells for various treatment and research purposes. It is important to stress that they are not derived from eggs fertilized in a woman’s body and that they are produced in a plastic laboratory culture via clinics in vitro.

Some examples of embryonic stem cells being used in research include the following:

1. UCLA stem cell gene therapy cures bubble baby disease

Researchers at UCLA (University of California, Los Angeles) have developed a cure for babies born with Bubble Baby Disease, a rare and life-threatening condition that can be fatal within the first year of life, by using stem cells from multiple patients and gene therapy to correct the genetic mutation of these patients.

2. Asterias biotherapeutics restores some independence to those suffering from paralysis caused by spinal cord injuries

Asterias Biotherapeutics spent much of 2016-2017 developing a stem cell therapy to restore upper body motor function to quadriplegic spinal cord injury victims. Through lengthy and rigorous testing in human clinical trials, the therapy was found to be safe for use in people with all patients treated reporting at least some improvements. Asterias is now expanding its clinical trials to include patients with sub-acute injuries.

3. UC Irvine scientists engineer stem cells to destroy cancer

In a study conducted by University of California, Irvine researchers, a stem cell-based technique was devised to find and destroy breast cancer cells that had already metastasized. The cells “feel” the stiffness of the surrounding tissues and destroy the cancer-causing cells.

Embryonic stem cells can remain undifferentiated when they are grown in a well taken care of culture that is under stable conditions. Problems primarily begin to arise if cells are allowed to clump together to form embryoid bodies in which they begin to differentiate, or change into more specific cell variants, spontaneously. Although spontaneous differentiation is a good indication that shows which cultures of embryonic stem cells are healthy, the process is uncontrolled and, therefore, an inefficient strategy to produce cultures of specific cell types.

The ability of stem cells being able to differentiate into hundreds of other types of cells continues to amaze scientists as this is no small discovery. Researchers believe that the possibilities with stem cells are near endless, especially in regard to “regenerative medicine,” the process of “replacing, engineering, or regenerating human cells, tissues, or organs to restore or establish a new function.” It is even believed that even whole organs could be synthetically grown by using them.” Additionally, stem cells have the potential to rebuild healthy tissues, help people with heart disease, diabetes, ALS, Alzheimer’s disease, liver disease, Parkinson’s disease, cancer, and many more illnesses.

In a stem cell transplant, embryonic stem cells are first specialized into the necessary adult cell type. Then, those mature cells replace tissue that is damaged by a disease or injury. This type of treatment could be used to:

• Replace neurons damaged by spinal cord injury, a stroke, Alzheimer’s disease, Parkinson’s disease, or other neurological problems.
• Produce insulin that could treat people with diabetes and heart muscle cells that could repair damage after a heart attack
• Replace virtually any tissue or organ that is injured or diseased.

Sometimes scientists use stem cells as a drug. For example, it is possible to inject a stem cell into joints to reduce swelling and pain, or in order to promote the healing processes of soft tissues. Stem cell therapy is performed by injecting the patient’s own stem cells to stimulate the body to repair and replace damaged tissue in any joint or soft tissue structures – such as knees, shoulders, hips, wrists, ankles, elbows, tendons, ligaments and non-healing bone fractures. Cellular Dynamics, a large biotechnical company, sells human heart cells called cardiomyocytes that are derived from induced pluripotent stem (IPS) cells. Pharmaceutical companies are adapting to this new and innovative trend on a day-to-day basis. Stem cells can also be used to test the quality and safety of investigational drugs by testing them on stem cells that have been transformed into tissue-specific cells. Researchers are able to monitor the side effects before exposing the drug to a patient and thus have a greater expectancy of how their body may respond to the drug. This allows us to test for cures for potentially fatal diseases in ways that would otherwise be risky or unethical.

With all of the aforementioned advantages, stem cells are a fairly new, but exceptionally promising, research area. For some people, it may seem unethical to use stem cells on the grounds that extracting stem cells damages the blastocyst, which is a structure formed in the early development of mammals, more specifically the sixth or the eighth day of the development of an embryo. In 2006, President Bush vetoed the Stem Cell Research Enhancement Act stating that the federal government should not support “the taking of innocent human life.” Although stem cells are very promising for science and can open new doors to many new treatments in the medical field, it looks like there are still differences of opinion on their ethical use. This is perhaps because there is need for more convincing evidence or people are not informed accurately on the details of this research area.

References

• https://stemcells.nih.gov/info/Regenerative_Medicine/2006Chapter1.htm
• https://www.healthline.com/health/stem-cell-research
• https://www.statnews.com/2017/04/26/stem-cells-cancer-mutations/
• https://plato.stanford.edu/entries/stem-cells/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5398703/
• https://www.mayoclinic.org/documents/the-amazing-stem-cell/doc-20249792
• https://www.unmc.edu/stemcells/educational-resources/history.html
• https://www.cirm.ca.gov/patients/power-stem-cells
• https://www.nature.com/news/stem-cells-take-root-in-drug-development-1.10713
• https://hsci.harvard.edu/examining-ethics-embryonic-stem-cell-research#:~:text=Opponents%20argue%20that%20the%20research,taking%20of%20innocent%20human%20life.%E2%80%9D

Embryonic stem cells are cells in the early stages of embryonic development when a fertilized egg cell is divided first into two cells and then into four, eight, and sixteen. Each grows into a brand new cell type and multiplies as per the codes present in its DNA program as tissues form and organization starts. 

After twenty years of research and accompanying debates on the human embryo, we are finally on the threshold of both reshaping our present concepts in biology and moving on to clinical case studies. The first human embryonic stem cells were produced in 1998. Studies researching the question, “Can we treat diabetes by reprogramming the DNA in these cells at the beginning of life?” switched first to how human genes worked and which genes are responsible for the development of particular tissues and then to the embryonic stem cells for these areas and ultimately to replacing or reprogramming a “faulty or deficient” gene.

The most controversial topics in genetics and embryonic studies are related to bioethics. Many scientists are grappling with questions like whether is it ethically correct to intervene with the genetic programming of a fertilized human egg (zygote)? If so, what should be the limits? Are we trespassing a divine domain?

Embryonic stem cells have been an excellent source of information that we lacked throughout history about how living organisms started to develop. Like astronomers who trace their knowledge to the Big Bang in order to obtain fundamental information about the origin of the universe, biologists have been researching how the molecules in a single cell went through sequential and planned changes, how they transformed and acquired new functions that triggered the mind-blowing developments in diverse, miraculous living organisms. Scientists have found out how primordial embryonic cells transformed into more than 200 cell types that constitute various tissues and organs. The number of studies has skyrocketed about which molecule types can be used to regenerate the damaged tissue, say, after a traffic accident. Embryonic studies that focus on the regeneration or reparation of medulla cells (spinal cord) have been a source of hope for some patients with permanent paralysis because of a broken back injury or severed spine in a traffic accident or those who are still stranded in wheelchairs. Similarly, the preliminary findings of research into Parkinson’s and diabetes are extremely promising, and a new study reports of two blind people with macular degeneration (which causes blindness) who have been treated.

Initial studies

In 1981 researchers successfully obtained stem cells from a rat embryo culture. They soon realized that the cells held a secret potential: they could grow into 200 different types of cells. Later Wisconsin-Madison University biologist James Thomson derived stem cells from primates for the first time. Three years afterwards, Thomson derived the first human embryonic stem cells from donated but unused embryos.

The increasing number of research studies into embryonic stem cells sparked off intense debate both in religious circles and among the science community that care passionately about the sanctity of humans. Allegedly, lab studies were conducted on human embryos without restrictions, which were grown until tissues and organs formed but were then killed. In 2001, the US president George W. Bush slashed federal funds, stating that stem cell research was not strictly ethical. Deriving embryonic cells was banned in many countries including Germany and Italy. In other countries, however, studies went full speed ahead. Indeed, reports flooded in about stem cells grown by researchers in Australia, Singapore, Israel, Canada and the USA into nerve cells, immune system cells, and heart cells.

Before long, a new idea emerged about transferring new cells into the egg cell – like nuclei of body cells used in cloning Dolly the sheep – to produce various tailor-made, fully DNA-compatible tissues and organs, as they had the same genome as the donor’s. It became a topic of everyday conversations that spare organs could be cultivated for the human body just like spare parts of cars or other machinery were produced to replace a faulty or damaged part. In fact, if it were not for claims such as “creating a new human” there would be no objections against producing a kidney, lung, or heart from the DNA of a patient and thus overcome the major problem of tissue rejection in transplantation of organs.

If faulty or defective genes could be removed and replaced by healthy genes in the DNA of stem cells, many incurable genetic diseases could easily be fixed and many prospective parents who avoid having a child because of a defective gene they carry would welcome the development enthusiastically.

We are on the threshold of reshaping our present concepts in biology and moving on to clinical case studies. Embryonic studies have been a source of hope for even patients with diseases like paralysis and blindness.

Just in time and in the right amount

Embryonic stem cells are cells in the early stages of embryonic development when a fertilized egg cell is divided first into two cells and then into four, eight, and sixteen. Each grows into a brand new cell type and multiplies as per the codes present in its DNA program as tissues form and organization starts. It is most mysterious and miraculous that the molecules that lead a stem cell to transform into a new type of cell are synthesized at exactly the right moment and in the precise amount.  Scientists are currently trying to figure out which molecule leads a cell to become a nerve, muscle, or bone cell when attached to it. They are likely to decode the molecules by monitoring the tissues that remain undeveloped because of missing genes resulting from DNA mutations observed in certain genetic diseases.

The new field that has developed in the last two decades called regenerative medicine is predicated on tapping into the potential of stem cells by repairing missing or faulty tissues, or completing a link in the chain necessary for the functioning of a dysfunctional metabolic process. In 2006, stem cell biologist Shinya Yamanaka of Kyoto University in Japan successfully transformed adult rat cells into an embryonic state. The following year, human body cells were transformed into embryonic stem cells. The ensuing research has led to the acknowledgement that it was theoretically possible to transform stem cells into any cell type, a promising cure for diseased embryos that have genetically missing parts.

The major problem, however, is keeping these delicate cells alive in a culture medium. In 2007, Yoshiki Sasai discovered a molecule called rock inhibitor that nourished the cell colonies he grew. The success rate in generating new cell colonies rose to 27%. Parmar from Swedish Lund University heralded “a new golden era” by producing new neurons from embryonic stem cells for the treatment of Parkinson’s.

As new techniques were developed for producing cells fast and reliably, these cells turned out to involve a very low risk of developing cancer. “We don’t yet know how this hidden power and balance that can be transformed into any cell type is controlled,” states Hiromitsu Nakauchi, a stem cell biologist at Tokyo University who researches making blood platelets out of stem cells derived from the embryo or somatic cells.

Experiments are underway that aim to treat disorders by activating stem cells stored in the body that have not yet differentiated through the help of proper stimulating molecules. 

Miraculous differentiation

As the techniques for producing and feeding stem cells got easier, researchers aimed at growing and forming tissues and organs. A connective tissue or an outer covering like the skin that lacks a shape but takes the shape of the underlying muscles and bones can be produced even in a Petri dish and then transplanted to a burned or missing area of the skin. The present aim is the production of organs such as the kidney or the heart that has a particular shape and is made up of a number of different tissues. If the correct signal molecules responsible for cell division and differentiation can be identified and readily used where necessary and at the right amount, then organs including any type of tissue can be produced. Researchers like James Wells at Cincinnati Children’s Hospital in Ohio have tested the damage of drugs on intestines by using the partial intestines they developed from stem cells rather than administer them to normal humans, thereby hailing the imminent age of intestine transplants.

In 2004, the doctors who did tube baby experiments for a patient in Chicago known to have a genetic disorder started to produce a series of stem cells from generated embryos. They made models at the cellular level of the emergence of such genetic disorders as thalassemia, Huntington’s disease, Marfan syndrome, and muscle dystrophy. In 2007, they used embryonic stem cells to suppress molecular changes that trigger mental disorders caused by a genetic disorder called fragile X syndrome.

Research shows that multipotent (mesenchymal) cells stimulated at the outset of tissues are even more promising than embryonic cells with respect to diseases because it is easier to repair damaged or missing tissue by guiding them. However, it is essential in a genetic disorder that cells derived at the beginning of the embryonic stage should be used in order to replace faulty genes with healthy ones and address the disorder at its outset.

Experiments are underway that aim to treat disorders by activating stem cells stored in the body that have not yet differentiated through the help of proper stimulating molecules. In this way, as many as ten illnesses are likely to be treated, some of which include diabetes, macular degeneration in the eye, and neurodegenerative diseases such as Parkinson’s.

Douglas Melton from Harvard Stem Cell Institute in Cambridge has worked for fifteen years to transform embryonic stem cells into insulin-producing β-cells. He has produced pancreatic cells that sense glucose and produce insulin and he hopes to transplant them to end the dependence of patients of diabetes type-1 on insulin shots. The last obstacle remains to be the introduction of these cells to the system so that they are not destroyed by the patient’s immune system.

Clinically, it is believed that stimulated multipotent cells have a greater advantage than embryonic cells because the produced cells and tissues have the same DNA as the patient and thus do not cause any immune reaction when they are transplanted. The problem for many genetic disorders including type-1 diabetes is that the patient has the same mutation in his or her genes, and a method should be devised for cleaning and replacing these cells.

Another problem is the cost. It is reported that preparation of a series of multipotent cells will cost about one million dollars. However, the cost is expected to decrease and cells will be developed for the treatment of Parkinson’s disease, which is caused by a loss of neurotransmitter substance, which enable communication between nerves, and dopamine.

Treatment of macular degeneration is a popular target in this field. Patients gained the ability to read, though slowly, one year after the transplantation of part of stimulated multipotent cells to a damaged retina.

Such research studies normally cause some opposition. Playing with genes and embryos involve certain ethical and health risks. Yet, as reported in a Prophetic tradition, with all our God-given abilities like intelligence, curiosity, and willpower, humans can, and hopefully will, find cures for all diseases. Research into stem cells has the potential to provide many breakthroughs in these efforts to find healing for every human. Scientists and ethicists have to work together to determine our direction not to cause any unintended harm to any single soul while moving forward with this research.

Brunger JM et al. Genome Engineering of Stem Cells for Autonomously Regulated, Closed-Loop Delivery of Biologic Drugs. Stem Cell Reports, April 2017.

Arthritis is an ancient disease that is associated with swelling and inflammation of the joints. It often results in stiffness, pain, and restriction of movement. In most cases of arthritis, the range of necessary treatments is very limited and common pharmaceutical treatments simply relieve the symptoms. However, a new study using stem cell technology may lead to the development of an arthritis vaccine that specifically targets inflammation in joints and stops pain before it even starts. Researchers used CRISPR technology, a revolutionary gene-editing tool, to reprogram mouse stem cells to combat inflammation caused by arthritis. These newly generated stem cells are called SMART (Stem cells Modified for Autonomous Regenerative Therapy). They are designed to develop into cartilage cells that produce anti-inflammatory agents. They also end up replacing damaged cartilage, reducing chronic arthritis-related inflammation. Researchers hope to package these reprogrammed stem cells as a vaccine for arthritis, which would deliver an anti-inflammatory drug to an arthritic joint, but only when needed. Current arthritis medications are given systemically, meaning they have the potential to interfere with other parts of the body. Since SMART cells deliver the medication only to the targeted location, this will significantly reduce the systemic effects. The question is: will they be effective? In trials, SMART cells were observed to grow into cartilage tissue and even protect against inflammation over the course of a few days in mice. Further testing is still in its initial phase in mouse models. These stem cells have been engineered to fight rheumatoid arthritis.

Plastic-eating caterpillars

Bombelli P. et al. Polyethylene bio-degradation by caterpillars of the wax moth Galleria mellonella, Current Biology, April 2017.

Plastics are made of synthetic materials consisting of polymers, long strings of molecules derived from fossil fuels. Since they have a half-life of approximately 450 years, every piece of plastic that has ever been made is with us today, except for the very small amount that we’ve burned. Polyethylene, from which plastic bags are manufactured, is one of the plastic types that is the most resistant to degradation. Since stores give out more than one trillion polyethylene plastic bags every year, these indestructible plastics are accumulating all over the globe and pose serious environmental problems. Scientists have long been searching for effective and environment-friendly solutions to eliminating plastic trash. One approach is to exploit simpler organisms, as they can be adept at utilizing unusual energy sources. After a lot of trial and error, researchers found that larva of a common insect, Galleria mellonella, is able to biodegrade polyethylene. Galleria mellonella, whose larvae are also known as waxworms, was discovered to do a significant amount of damage to a plastic bag in less than an hour. The follow-up tests detected the presence of the basic building block of polyethylene, ethylene glycol, in the waxworms’ guts, demonstrating that the waxworms were indeed digesting polyethylene; they were not merely chewing it up into smaller pieces that passed through their guts unaltered. These results were initially puzzling to scientists; they couldn’t understand how waxworms were able to digest a substance that had only begun to be manufactured in the last century. The answer came from the ecology of the waxworm itself. Waxworms are a well-known pest to beekeepers, as they grow and feed on wax and honey. Since wax is a polymer with a very similar chemical structure to polyethylene, waxworms seem to already know how to digest polymer structures like plastics. Scientists still don’t know whether the polyethylene digestion is done by the waxworm itself or if it is relying upon the bacterial flora within its gut. As they learn more about the digestion mechanisms, they hope to design practical and effective biotechnological solutions for managing plastic waste, which will ultimately protect our oceans, rivers, and overall environment.

Pill for exercise?

Weiwei F et al. PPARδ Promotes Running Endurance by Preserving Glucose. Cell Metabolism, May 2017.

The benefits of exercise are well-known. Unfortunately, there are people who are obese, elderly, or mobility-limited and cannot benefit from exercise. To offer them a solution, scientists discovered a drug called GW1516 which mimics the beneficial effects of exercise, including an increased stamina and a higher rate of fat burning. While the control mice could only run 160 minutes on a treadmill, mice with the experimental drug lasted 270 minutes—about 70 percent longer. The discovery of GW1516 came from scientists’ previous knowledge of genetics. Scientists already knew that genetically activating the gene called PPAR delta enabled mice to run a lot longer than normal without getting tired. Moreover, these mice are much less likely to gain weight or become diabetic. Scientists basically designed a chemical compound that activates the PPAR delta. The research team also analyzed the wide range of physiological effects of GW1516. While the genes that break down fat for energy did more work in the mice with GW1516, genes that break down carbs for energy did less work. This is somewhat expected, as the bodies of really fit people typically burn fat, not carbs, for fuel. Despite these differences, GW1516 didn’t improve muscle mass. The only benefit seems to come from changing how the body breaks down energy. Although the initial studies have been done in mice, scientists are eager to develop clinical trials for humans as soon as possible.

One of the processes that occurs in the body is called “inflammation.” Inflammation occurs when a cut into the skin also punctures a blood vessel. This situation directly exposes the blood to the air. Inflammation occurs in a few steps. First, the blood vessels near the wound are expanded (which causes the swelling that we see near the cut) and special proteins called “fibrins” are brought in. These fibrins bind to each other to form a net-like structure. We are all quite familiar with this net, which we call a blood clot. This net stops the bleeding and cuts the interaction between the air and the blood within a few minutes.

Next, it is time to quickly eliminate any foreign objects that got into the tissue. Special immune cells called “macrophages” are sent to the crime scene to clean up. Macrophages are large white blood cells that “eat” microbes and other foreign objects using a process called “phagocytosis.” After the scene is all cleaned up, these macrophages excrete special molecules that induce tissue repair and return the blood flow to normal. An important note here is the specific order of these events. Like every single process in the body, they occur in the most purposeful way possible. What do I mean? I mean that, first the wound is closed urgently; second, macrophages are sent in; third comes the tissue repair. Any other order would have greatly lowered the effectiveness of inflammation. Imagine that the wound is closed after the macrophages are sent in. Then, by the time the macrophages killed all the microbes, twice as many would have entered the scene. The body seems to know every single event beforehand and plans its defense accordingly.

Our body is perfectly calibrated to keep our blood, the milk of our organ systems, absolutely pristine.

Let’s say a microbe managed to sneak into the blood before inflammation occurred, and is long gone to another region of the body. Does the microbe win? Unfortunately for the microbe, it has to pass another test. This time the tester is the lymphatic system. The lymphatic system is the sewage system of the body. When the blood transfers its nutrients to the tissue, the fluid goes through the “interstitial area” (the empty space between organs). During this process, some of the fluid stays in this area and starts to accumulate. This is where the lymphatic system kicks in. The lymphatic system consists of many tubes running parallel to the blood vessels and recollects any excess fluid and transports them to the subclavian vein near the neck. This way, excess fluids of the body and all of the molecules in them, are reintroduced into the circulation. If there is a problem with this process, an abnormality called “edema” occurs. Of course, the blood is a very sensitive fluid because it travels through the whole body and seeps into almost every single cell. If a microbe were to get into it, it would easily spread and cause disease. So, the lympatics first does a checkup on the body fluid. This checkup occurs at special nodes in the system called lymph nodes found all over the body. Two of the most famous lymph nodes are the spleen and the tonsils. Within these nodes are lymphocytes, special immune cells that “tag” bacteria and other microbes to be later destroyed by macrophages. Thus, the blood is continuously cleaned and kept safe from harmful microbes.

Last but certainly not the least, the final inspection the blood goes through takes place in the kidneys. The aforementioned two checkpoints prevent the entrance of any foreign materials into the blood, and the elimination of any microbes lucky enough to somehow make it through. So, the only task to be completed is the elimination of excess molecules formed in the metabolism. For example, the blood in the veins (the vessels that carry carbon dioxide formed by the respiration of cells) is carried to the lungs where the carbon dioxide is exhaled. But, a much more precise mechanism comes into play in the kidneys. Blood vessels that come from all around the body form a knot-like structure in the kidney called the “glomerulus.” This knot-like shape increases the surface area of filtration. The blood running from the glomerulus is then filtered into the “Bowman capsule,” which surrounds the glomerulus.

But wait! The sanitation system is not satisfied with this first filtration and “thinks” that the filtrate is not ready to be excreted by the urine. So, a more delicate filtration occurs right after the filtrate enters the “proximal tubule.” While passing through this tubule, essential molecules are immediately reabsorbed into the body. The most valuable of all these molecules is glucose, since it is the main source of energy in the body. The proximal tubule reabsorbs around 98 % of all the glucose, while the distal tubule scouts out the rest. After the tubules are done with the filtration, not a single glucose molecule is left in the urine. As a matter of fact, the presence of even a few glucose molecules in the urine leads to a diagnosis of “renal glycosuria.”

After the proximal tubule, the filtrate goes into the “loop of Henle,” where it is dipped into a high-concentration environment. Water travels passively (without the need for energy) from low-concentration to high-concentration areas. In the loop of Henle, the urine is low-concentration, so water runs back into the body. Thus, any excess water in the urine is effectively and economically reabsorbed. The big machine that consists of the glomerulus, the Bowman capsule, the tubules, and the loop of Henle is called a “nephron.” Everything described above occurs in a single nephron. The average number of nephrons in one kidney is around 1,000,000. The human bladder holds around 150 ml of urine on average. So, each nephron is actually responsible for 0.00015 ml of urine production. The kidneys filter over 1,000 liters of blood each day, so our blood is kept just as we want it. Millions of tiny nephrons work in unison to take in huge amounts of blood and they know exactly what to leave and what to keep, 24 hours a day, 7 days a week.

Our blood is our life source. It is the milk of the organs, and our organs would dry up without it. Believe it or not, our organs are quite picky. If they are to receive anything they don’t like, they will start acting up. In order to keep the organs happy, the three mechanisms mentioned above have to work hard and not make a single mistake. These mechanisms are, of course, also made up of cells. These miniscule cells “know” exactly what their clients on the ends of the body like and don’t like, and prepare the blood composition accordingly. Only one word can describe these wondrous mechanisms: Impeccable.

Brian Turk is a medical student from New Jersey. He writes on medicine, health, and biology on a freelance basis.

Because stem cells are rare in the tissues (one out of ten thousand) and we are constantly losing them, our body cannot grow, maintain, and repair itself continuously. This is the main reason for the wear and tear on our bodies as we get older. Nevertheless, assuming that there should be a cure for any illness except death, the clinical research on stem cells is quite promising with respect to many diseases. The One Who has placed stem cells in our body as a source of auto-regeneration, has also given us the idea that we can possibly discover the laws of stem cell production for use in medical treatment. Stem cells are the cells that all cells stem from. What makes them different from other cell types is their capacity to divide infinitely, their ability to differentiate when they are subjected to biochemical and environmental signals. Stem cells can form other cell types with specific biological functions. They can give rise to all the mature cells for the heart, the skin, the nerves, the cornea, and so on.

The potential of stem cells for new therapeutic approaches is highly encouraging and stem cell studies have become one of the most active areas of research in biomedical sciences. Researchers are attempting to identify the unique features of stem cells which can be used in medical applications. It is believed that the correct use of stem cells will enable doctors to heal and regenerate damaged tissues and organs, and cure many genetic disorders. In the near future, stem cell studies are expected to provide direct solutions for conditions caused by other cells’ lacking the ability to divide and self-renew. These conditions include Parkinson’s, Alzheimer’s, spinal cord injuries, heart attacks and heart disease as well as blood cancer, diabetes, and bone loss.

Moreover, the potential of stem cells to reduce the effects of aging make it seem likely that in future there may be seventy-five-year-olds with the healthy bodies of teenagers. Stem cells as an alternative to organ transplants The most straightforward application of stem cell research has been as a new source for tissue and organ transplants. This is a great alternative for patients who are waiting for a donor organ. It is known that in the case of organ transplant from a donor, even from the closest of relatives, the body rejects any foreign tissue and special drugs are needed to suppress attack by the immune system and to lower the rate of rejection. Since stem cells are genetically the patient’s own cell, rejection is not an issue in stem cell transplants. One of the best studied areas of stem cell research is the treatment of heart failure. Cardiac muscle cells are complex and unable to generate new cells. Cell death in cardiac muscle causes serious heart failure due to ineffective muscle contraction in the heart. In addition, when a patient has successive heart attacks and myocardial infarctions (death of cardiac muscle resulting from interruption of the blood supply), the number of dead cells increases because of the decreased level of oxygen reaching the heart tissue. This usually leads to the death of the patient after the third heart attack. The conventional therapy uses the insertion of a small tube, a stent, to fix the artery and to increase the level of oxygen reaching the muscle cells.

However, this method cannot effectively compensate for the dead cells. To recover cellular losses, potential stem cells from bone marrow were collected and then processed to prepare cardiac muscle stem cells. They were then injected into the damaged area which led to the production of new healthy muscle tissue. The size of the dead area decreased notably and the performance of the heart improved. In one study performed at the University of Wisconsin, initial trials resulted in patients feeling better with less chest pain and improved exercise capacity. Skin production for severe burns Severe burns to the skin require long and painful treatments and usually result in scarring and disability. Although current treatments, such as skin grafting and the use of artificial skin technologies, suffice to re-cover the injured area, they are not adequate for the regeneration of functional skin following burns. Scientists aim to produce skin cells in the laboratory by using the patient’s own stem cells. This would lead to replacing the damaged area of skin with fully functional tissue readily, without pain or long-lasting treatment procedures. Type I diabetes and stem cell therapy In type I diabetes, cells that produce the insulin hormone are destroyed by white blood cells. So, the body can no longer produce insulin to balance the sugar level in the blood.

People with type I diabetes need to take insulin injections daily. However, in one recent study, a team of American and Brazilian scientists used stem cells obtained from patients’ own blood to regenerate insulin-producing cells in their bodies. According to the study leader, Dr. Julio Voltarelli of the University of Sao Paolo, results are very encouraging. For example, one patient has been free from insulin injections for 35 months. Fourteen out of fifteen patients were cured. Although some still have different level of insulin dependence, they no longer need a daily insulin intake.Ethical concerns about stem cells Stem cells can be produced from various sources. The human embryo is probably the best source to obtain stem cells, since embryonic stem cells (ESC) have a higher ability to divide and readily undergo cell differentiation during early development. The embryos that are used for research are generally obtained from the remnants of in vitro fertilizations or from abortions (premature termination of a pregnancy). However, the use of human embryos for stem cell research is very controversial. Objections to embryonic studies arise because the studies involve interference with human life at the early stages and uncertainties about when life begins. Ethical and legal disputes have resulted in the prohibition of ESC research in several countries. Embryos are not the sole source of stem cells. They can also be obtained from many adult tissues, especially bone marrow, the placenta, and umbilical cord. These sources are not considered ethically problematic, but stem cells obtained from adult tissues have less ability to differentiate into various cell types. In addition, adult stem cells cannot be isolated easily from tissues, and the growth of these cells in culture takes more time than that of embryonic stem cells. The challenge is to find the balance between hope for cure and respect for life. The question when life starts or a fetus has been given a soul is a subject for religion and philosophy. According to Catholics, for instance, the human embryo is valuable and one must consider the zygote (a single cell that is the result of fertilization) a human being. Thus, embryos or zygotes cannot be killed, stored, or used for any purpose. However, the Catholic Church allows that research on adult stem cells can be carried out for medical research. In contrast, Jewish religious leaders do not consider the zygote or blastocyst a complete human being. They hold that embryonic stem cell research can be done if it is beneficial for humans and if it does not cause any problem for human life. Islam favors all studies beneficial for humanity and society if they do not raise ethical or spiritual issues. Islam especially supports the use of adult stem cells for stem cell studies. It also allows studies on blastocysts remaining after in vitro fertilization if there is no cure available by other means and there is no economic gain from the donation of blastocysts for research and stem cell therapies. Consequently, ethical issues related to ESCs have resulted in a search for alternative sources for stem cells that has the utmost importance for the scientific, religious and social sphere.

Placental and umbilical cord blood stem cells

Even though intensive care units for new born babies are developed with the most recent technology, they are yet way too primitive and insufficient, compared to a several-kilogram organ in mother’s womb. This organ, which is also featured as the real hero of birth by scientists, is called placenta. The placenta is an organ whose main role in pregnancy is the exchange of any material required for embryonic growth such as gases, nutrients and hormones from the mother’s blood and the removal of toxins and biological waste from the fetus. It also functions as a barrier against any immunologic attack on the embryo by the mother’s immune system so that a foreign body (a baby) can survive in the mother’s womb. In addition, it has important metabolic and hormonal functions. Fifteen years ago, researchers discovered that the placenta has a large number of high quality stem cells. These cells could be extremely important for the baby in the case of any genetic or metabolic problem causing tissue loss or damage later in life. The placenta can be stored just after birth. In addition, it is very probable that these stem cells will be a good source for cell therapies for relatives. Who could have thought that the remnants of birth would have such importance in medicine fifty years ago? The One Who, with the highest wisdom, creates every single thing with many purposes has made placenta and cord blood a useful source of stem cells.

The advantages of stem cells from cord blood

Stem cells isolated from cord blood are the youngest after ESCs. They have a higher ability to divide than commonly used adult stem cells from bone marrow. In contrast to bone marrow, stem cells isolated from cord blood can be used for family members because they do not interact with the immune system and they do not cause any negative response. Moreover, they are more durable than adult stem cells and can be stored for a long time by freezing the placenta and umbilical cord. They also do not contain tumors or viruses. These juvenile stem cells can easily transform into many cell types and tissues if they are sent the correct biological and genetic signals in the culture environment. Nowadays, stem cells isolated from cord blood are most commonly used to support the blood and immune systems in patients with cancer who are being treated with chemotherapy and/or radiotherapy. Recently, some clinical studies have shown that they can also be useful for treating blood cancer. The flexibility of stem cells obtained from cord blood offers hope that stem cell studies will increase the prospects of treatment of these diseases.

Restoring vital body functions: What does the future promise?

Discoveries are emerging every day about stem cells. As we have shown, stem cells might be the key to the replacement of lost cells in many devastating diseases. Some day, diseases like Parkinson’s, diabetes, chronic heart failure, and liver failure may be history because of stem cell technologies. The aging process might be slowed by compensating for the effect of tissue loss with stem cells. There is also great hope of finding an alternative to organ transplantation, for which currently there is a lack of sufficient and suitable donor organs. For instance, in the case of liver failure, healthy cells produced from stem cells can be injected into the patient. Moreover, by using a liver-like environment, it may be possible to produce a complete or partial liver for transplant. Another fascinating potential benefit of stem cells lies in the possibility of regenerating nerve cells in the spinal cord after injury. There is always hope of a cure. The scriptures contain many examples of miraculous treatments of disease at the hands of the Prophets.

These miracles are not only proof of their prophethood, but also indicate the upper limits that humans can reach by means of knowledge. For instance, recently a scientist in London was able to cure some patients of blindness using their own cells. In this case, age-related degeneration of retinal cells was causing the blindness. Professor Peter Coffee, from the Institute of Ophthalmology, reported that they reversed the condition by transplanting cells taken from the side of the patient’s eye and embryonic stem cells into retina to replace the dead cells. This kind of study reminds us of the miracle of Prophet Muhammad peace be upon him who healed the eyesight of a blind person simply by his touch.

Thanks to the Human Genome Project, we now have tools to manipulate the deciphered sequence of our DNA. The combination of our knowledge about the genome with stem cell technology may allow us to approach the limits defined by the miracles of these perfect examples of humanity. In the meantime, future research should be carried out with due regard for its effects on society, humanity and environment and keeping in mind all the possible ethical issues and consequences of our actions.

Ali Fethi Toprak is a PhD candidate at Southwestern Medical Center, Texas University.

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Placenta.Wikipedia. http://en.wikipedia.org/wiki/Placenta

Stem Cell Therapies Today. genetics.utah.edu/units/stemcells/

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Cordon Blood. Ãlmi Mercek Journal. http://ilmimercek.net/index.

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