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Stem Cells Hereditary Diseases
Hereditary diseases have long been a problem plaguing the medical profession due to the inherent difficulties associated with combating both their development in a growing organism as well as the potential for them to be passed on from parent to offspring. The advent and subsequent development of stem cells in the medical world has opened up a realm of new possibilities for many researchers, however, both in the form of germ line therapy and somatic gene therapy.
Germ Line Therapy
The essence of germ line therapy comes from modifying actual heritable traits present in germ cells (such as sperm and egg gametes) that can be passed down from one generation to the next. This form of treatment has been seen as highly advantageous in many ways over other treatments as it can both effectively eliminate a hereditary disease before it even begins to develop in an individual while at the same time prevent the disease from being transmitted to additional offspring.
Unfortunately due to the fact that this particular type of treatment involves the direct modification of gamete cells it has met substantial opposition to counter its support from a number of people worldwide as it effectively modifies pre-set standard DNA chains in order to eliminate undesirable attributes. Further, due to the fact that any modification of a germ cell in this sense would require an in-depth understanding of the target subject’s genome and what each individual aspect corresponds to this can make pinpointing and eliminating specific genetic code challenging at best.
Somatic Cell Therapy
Unlike the heritable cells generated from germ line therapy, somatic cell therapy works to treat specific cells affected with an inherited disease without generating any heritable characteristics. Many times somatic cell therapies come in the form of modified viruses designed specifically to target key DNA lines in infected cells and eliminate the trouble zone in order to cure an ailment. Alternatively they can also be used to generate necessary cells or tissues that would also otherwise not be present due to a hereditary problem, allowing for more immediate treatment to occur.
While somatic cell therapy has generally been much more welcomed by most social and scientific groups due to the fact it has no long-term heritable effects upon a body at the same time it is for that very reason that it has some significant drawbacks. In many cases somatic cell therapy must continue for extended periods (and sometimes indefinitely) in order to function properly due to no real change occurring within a targeted cell and a direct treatment, while effective, may never actually cure a hereditary disease from recurring due to the fact that they are generally coded into an individual’s DNA from the time of their initial conception.
Subscribe to the comments for this postStem Cell Timeline
Although stem cells have generally been considered a modern development the actual history leading up to stem cell development spans centuries, from the 1800s to modern-day scientific application:
Mid-1800s – Cells were first discovered as the basic building blocks of life, with some cells being noted as having the capability of producing other cells within a body.
Early 1900s – During attempts to fertilize mammal eggs outside of parental bodies it was discovered that some cells had the capability to produce blood and generate additional cells for fetal development.
1968 – The first successful bone marrow transplant was performed in order to treat two siblings suffering from combined immunodeficiency syndrome, a landmark breakthrough in adapting one individual’s cells to a foreign body.
1978 – As a result of further investigation into human cell development and application in science stem cells were first discovered in human fetal cord blood.
1981 – The first in vitro (test tube) stem cell line was developed from laboratory mice, providing a basis for further studies into other cell development trends in other mammals
1988 – Embryonic stem cell lines were first successfully derived from a hamster, leading researchers further down the line towards modern-day developments by broadening the scope of focus for cell sources.
1995 – The first primate embryonic stem cell lines were developed, allowing for a more realistic study of cells that develop close to human-like characteristics.
1997 – Two major discoveries took place this year, both in the form of successfully cloning a sheep from ovine stem cells (proving that the central DNA structure found within the stem cell structure is fully compatible to an entire living creature) as well as leukemia’s origin being discovered as residing in hematopoietic stem cells – potentially hinting at an actual cancer stem cell for further study towards combating cancer development.
1998 – Thompson at the University of Wisconsin successfully cultivated the first human embryonic stem cell line, sparking the first major ethical debate in terms of stem cell research and both its application to as well as effect upon human beings.
1999 and 2000 – Scientists discovered that by manipulating various tissues from adult mice they could generate different types of cells and stimulate growth, giving birth to the study of what is now commonly known as “adult stem cells” and both their collection from and application to fully developed adults (a much more ethically acceptable practice to most individuals).
Why Do Stem Cells Differentiate
Stem cells are in essence the primary building blocks of our bodies. First developed when we are forming in an embryotic state, stem cells are used to form the basic structures of our body (including the skeletal, nervous and various tissue systems that we need for our very survival). While in the initial stages of our development these cells are highly versatile and can be used for any number of different functions. This allows for one cell to easily replace another if that cell should be having problems, helping to ensure the healthy development of a child before it is born.
As our bodies develop, however, stem cells must specialize in certain tasks in order to allow our body’s different systems to both function independently of one another while still interlinking and working together as a single organism. This means that the previously highly flexible stem cells that could be used for any number of bone, tissue or nerve growth must focus on one particular area and differentiate themselves from other stem cells in order to be more easily used in that area later on should additional cell growth be necessary.
These cells can further be found differentiating even further as human being grow and develop themselves through childhood and adolescence. Puberty is a primary changing point where a number of new systems are established and in order to meet the body’s structural demands stem cells must work appropriately to handle those. This leads stem cells to focus or differentiate more and close off some developmental pathways while opening up others for our body’s use.
Although stem cells may become more and more specialized as we grow older this does not mean that they cannot be used in various different ways effectively with enough propagation and genetic coding. Recent scientific discoveries are finding new ways to “bend” stem cells harvested from adult bodies into new genetic structures to aid with tissue, bone, cartilage and nerve regrowth that the stem cell may not be involved with normally (such as recent reports from Japan of stem cells being able to be harvested from developing wisdom teeth for usage in various different areas of the body).
Unfortunately no matter how much scientists may “push” stem cells harvested from adults in a certain way there is only so much that they can do and the stem cells simply will not be effective in generating any and all body systems imaginable. This is due to the fact that the previous differentiation the stem cells have undergone during the body’s development (with either partial or full specialization towards a specific system or structure) in order to allow the cell to perform its job more efficiently and thoroughly simply makes them unsuitable for most usage far outside of their pre-determined realm. While this does not mean that they have no flexibility in usage outside of their normal areas the farther and more “foreign” the system or structure is to the originally specialized system or structure then the less likely the stem cell is to effectively form appropriately.
How Do Stem Cells Cure Diseases
In order to understand how stem cells have the potential to cure diseases it is important to first fully understand what stem cells are and how they relate to our bodies. First formed in an embryotic state, stem cells are cellular structures that are virtually a genetic blank slate – meaning that they can differentiate and change themselves to form tissue, bone or nerve cells as needed by a body during development. As we grow older and develop these cells specialize in specific tasks, forming our skin, skeletal structure, organs, nervous system and brain. Even our blood is formed through developing stem cells and generated through their specialization to that task.
As our body develops further some of these stem cells then compartmentalize into specific body areas to be used for cellular regeneration later on as needed. While these stem cells are generally less flexible than their embryotic counterparts due to the fact that they have generally partially specialized to a particular task (such as knee stem cells generally being best suited for knee bone, cartilage or fat generation) they are still flexible enough to be used by the body for whatever specific task may be needed at any given time.
Because of the flexibility and potential for stem cells to be used in so many different ways many scientists believe that they hold the cure for a number of different diseases affecting people today. As diseases generally target specific cellular structures and in many cases render them useless (such as the thalamus’ production of dopamine being rendered inactive in the case of Parkinson’s Disease) researchers feel that harvesting stem cells and “programming” them with the genetic code necessary to develop into a healthy version of the affected area and then re-injecting them into the body could effectively be used to treat or cure a number of different diseases, disabilities or even traumas such as spinal cord injuries that until now have been considered untreatable.
The primary limiting factors facing most stem cell applications in the treatment of human diseases lie in both the source of the stem cells as well as the actual usability of the end product down the line. Embryotic stem cells, for instance, have the highest ability to conform to any existing body structure and be effective in treatments, however the harvesting of these cells would generally mean the destruction of a human embryo for the sake of the stem cells’ harvesting and is therefore considered highly unethical (and is even banned in most countries by government mandate). Alternatively pre-existing stem cells harvested from adults could also be used, however these have much less flexibility in terms of usefulness and if taken from donors may also run the risk of the body rejecting the cell outright as a foreign organism.
Still, scientific advancements in terms of stem cell development and application to the treatment of diseases are progressing rapidly and many believe that many of the difficulties currently facing stem cell usage will be overcome in a few short years, allowing for the successful treatment and possible cure of many ailments.
Stem Cells Teeth
Teeth, or more specifically wisdom teeth that are generally removed by most dentists around the age of 20, have recently been determined to have the potential to be used as stem cell sources for development into various tissues and bone structures by Japanese researchers. Although the stem cells harvested from these teeth may not have the flexibility of some other stem cells (such as embryotic stem cells) they do allow for a convenient, ready source of stem cells for treatment and usage by medical professionals worldwide without the ethical stigma normally associated with stem cell usage.
Found to be viably harvestable by either utilizing a biological “pulp” formed from ground wisdom teeth or harvested directly from the teeth that have not been removed the mysenchymal stem cells have proven effective in generating a number of different biological structures, however pushing the envelope of their flexibility has been difficult due to the fact that the stem cells are harvested from pre-determined anatomical structures to begin with. This means that utilizing these stem cells in brain nerve regeneration, for example, may not yield the most desirable results, however facial bone regrowth may be a high probability.
One of the areas in particular that these new stem cells have shown excellent results in is the regrowth of teeth that may have been lost or damaged. Harvesting the stem cells and then programming them to regrow certain calcium structures has allowed researchers to actually replace lost teeth with real, natural structures, something that has been only theoretical in previous years and is a developmental breakthrough for those in the dentistry field.
What this means for most individuals is that the use of dentures and other false teeth may soon go by the wayside as real teeth can be simply regrown rather than lost forever. Combined with proper dental hygiene as well as many other government-driven oral protective measures (such as fluoride being added to drinking water and toothpaste to help fight tooth decay) the current “nexter” generation (those who are the offspring of the Baby Boomers) may be the first generation to have the majority of the people go from birth to death without losing one tooth to bad hygiene (though of course physical trauma is still a major concern for many and the primary result of lost teeth for professional athletes such as hockey players).
Currently studies are continuing into the actual usefulness the new stem cells may have in helping to rebuild different body structures and scientists are hopeful that they will be able to see actual human application in a few years. While this may seem quite a long time for most people a time frame of a few years from discovery to actual human usage is quite short, especially in terms of stem cell development. Still, since these cells are easily harvested from what is most often discarded material (as wisdom teeth are commonly simply disposed of after removal) as well as able to be directly harvested most researchers feel that there will be little restrictions placed on their exploration of the usage and patients should see real-world usage in under a decade.
Stem Cells Parkinson’s Disease
Parkinson’s Disease is an unfortunately relatively common disorder developed by individuals, with over one million reported cases existing within the United States alone. This highly debilitating disease starts as a small tremor in the hands or feet and eventually spreads throughout the entire body, causing many afflicted to lose the ability to walk or use their arms and hands effectively. Though there are a number of different treatments currently available there is no known cure for Parkinson’s Disease at this time.
Caused by neurological degeneration where dopamine generating cells in the sector of the brain known as the thalamus stop functioning the resulting dopamine deficiency causes the electrical synapses that drive all motor functions to miss-fire. In short this effectively means that an individual will slowly lose conscious control of their body’s motor functions, and while they may be able to maintain some semblance of muscle usage over time the progressive nature of the disease generally means that the conscious ability to control movement will become less and less over the course of a few years (or decades at most).
Because researchers known the cause of the disease as well as various hypothetical ways to treat the condition they feel that Parkinson’s Disease is a prime candidate for stem cell research that may one day lead to the actual curing of the condition. For instance, it is believed that by cultivating dopamine-generating brain cells and injecting into the thalamus would allow the stem cells to replace the currently defective cells causing the disease’s progression and potentially result in a quick, effective treatment and possible outright cure for the condition.
Unfortunately due to the limited research that has been done into stem cells as of this time because of various government regulations and other restrictions facing their exploration around the world stem cells are still far from being effectively used in actual human application and many believe that it will still be years before scientists will reach the stage where actual human trials will be viable. While this may be terrible news for many sufferers at the same time it is an unfortunate necessity due to the potential for stem cells to do more damage than good if injected into the brain without proper cellular preparation as well as a comprehensive understanding of how they will react both in the short- and long-term after being injected.
One of the primary concerns involved with stem cells is their potential to continue to develop unchecked into various forms of cancer. While this likelihood is still theoretical due to the limited amount of practical application that has been done in the past it is still a possibility and if any human applications are attempted before research has reached the appropriate level it could easily trade one disease for another. Still, most researchers anticipate that within the decade they will see some positive results from their studies, and if so then Parkinson’s along with a number of other ailments such as multiple sclerosis, ALS, Alzheimer’s or even spinal cord injuries.
Stem Cells Blindness
The first effective stem cell therapy that may cure the leading cause of blindness has recently been developed by British scientists. Surgeons are now predicting that it is likely to evolve into a common, one-hour procedure viewed by many as a practice that can be regularly performed in around seven years time.
With the total number of patients with AMD standing at more than 14 million in Europe alone it is clear that the ability to reach as wide a number as possible is definitely a positive thing. The clinical trial is likely to happen within two years and regulatory approval for trials is currently being sought by the team.
The treatment itself involves the replacement of a layer of degenerated cells with new cells that have been created from embryonic stem cells. The technique was first undertaken by scientists and surgeons at the Institute of Ophthalmology at University College London and Moorfields Eye Hospital. Pfizer, which is one of the largest pharmaceutical research companies in the world, has recently announced that it will inject financial backing into the project in order to ensure that the therapy is delivered to patients.
The disease results in the loss of eye cells. In the course of the new treatment embryonic stem cells are changed into replicas of the missing eye cells and are then placed onto an artificial membrane, while the membrane is subsequently placed in the back of the retina.
The treatment will be geared towards dealing with age-related macular degeneration, which is the most usual cause of blindness. AMD currently affects more than half a million people in the UK alone, and as populations begin to live longer than before many are predicting that this number will continue to rise in coming years – particularly with the large “Baby Boomer” generation nearing retirement age and requiring significantly more medical attention than previous generation groups.
Embryonic stem cells have the unique ability to transform into all different types of body tissue, although due to the fact that their use involves the destruction of human embryos any treatment technique involving their use remains controversial. The laboratory trials that have been finished by the British team, however, have shown that the stem cells are able to prevent blindness in rats that have a disease very similar to AMD and parts of the technology have also been successfully tested on pigs.
The chief executive of the Macular Disease Society, Tom Bremridge, described the news as “a huge step forward for patients” in terms of eye treatment. He also expressed his pleasure that major players like Pfizer had stepped forward and become involved as this will result in a larger number of patients being able to take advantage of the new treatment.
Professor Pete Coffey, the leader of the research team, stated that the treatment itself would in all probability “take less than an hour, so it could really be considered an outpatient procedure.” Professor Coffey also welcomed the involvement of Pfizer and their undertaking to manufacture the membranes, stating that “a major partner of their standing will really scale things up.”
Stem Cells Baldness
In order to fill the market need in hair (re)generation or hair loss therapy researchers have successfully reported that they have been able to coax stem cells into the production of live hair follicles. To attest to the general population’s need for such a treatment there are currently roughly six in every ten men above the age of 50 (and two in every ten by age 30) who suffer from hair loss, meaning a substantial market and general desire for some sort of long term treatment to be available. Beyond simple cosmetic needs, however, the recently announced hair loss treatment ability utilizing stem cells might also be useful for other conditions such as alopecia, where hair has been lost in patches, or for returning lost hair to cancer sufferers in order to help boost their self confidence in their fight against their disease.
The recent breakthrough was chronicled in the journal, Nature, where scientists told how they had demonstrated that adult mammals were capable of growing new hair follicles. Previous wisdom had held that the follicles, the minute structures that are responsible for hair growth, are always formed prior to birth and that their gradual and irreversible death leads to baldness. The new discovery, however, demonstrates the possibility of developing new hair follicles later in life which may well give the green light for successful future hair loss treatments.
The researchers at the University of Pennsylvania made the new discovery while investigating into the process of wound healing in mice. The Pennsylvanian scientists found that as the wounds in the mice healed new hair follicles formed underneath the new skin, thereby resulting in new hair growth. Upon close analysis the researchers found that the actual follicles were formed from stem cells that act as a form of “master cells” that are able to turn into different cells and tissues.
They also found that the key component of the whole process was a protein called WNT which is normally only active in the womb during child development. When levels of the protein WNT are raised it was found that more hair grows, whereas conversely without WNT there is no hair growth. Further, the researchers also discovered that adding WNT to the wound healing process allowed wounds to heal better and it is believed that, when the skin heals itself, it goes back to a state similar to that which is found in a developing fetus, thereby allowing the growth of new and fully functional follicles.
All work and research has thus far been limited only to mice, although researchers hope that similar techniques might result in treatments for humans as well. As it was found that wounding seems to be an integral part of the overall process it seems that the skin would need to be grazed in the area to be treated and then a form of WNT drug would be administered. At this point, though, all hair produced by studies has been white which means that any new hair grown would most likely need to be dyed in order to make it appear natural. Based on current research trends the first human trials might not be too far away, although any possible cure for baldness is not expected for at least a decade.
Stem Cells Spinal Cord Injury
Almost 300,000 Americans are currently living with an injury to their spinal cord and 12,000 people every year are informed that they will never walk again following an accident. There may well be hope, however, that a single injection of specialized stem cells may possibly return movement and hope to a paralyzed body. In fact one scientist who has dedicated a good portion of the last ten years searching for a cure has claimed that a new treatment may well be within reach. Should this prove to be the case it could mean that the treatment and repair of spinal cord damage will be revolutionized.
In a University of California laboratory researcher by the name of Hans Keirstead, Ph.D at UC Irvine believes that he may have found the vital pieces of the jigsaw to help patients with spinal cord injuries regain movement. Dr. Keirstead said that he has come up with a treatment designed to treat patients within two weeks from when they suffer an injury. He went on to comment that it is a scary concept that the people who will receive the treatment haven’t even suffered an injury yet.
In Dr. Keirstead’s study rats that had been paralyzed previously were able to walk again within six weeks, and from these results believes that human trials could begin very soon with perhaps ten patients receiving an injection of the specialized stem cells directly into their damaged spinal columns. It is hoped that, in these cases, small movements may been seen in the patients within three months. He made it clear, however, that he did not expect such dramatic and immediate results from his treatments.
Dr. Keirstead’s treatment comes from cases where he has successfully coaxed stem cells from human embryos into a condition wherein they can be easily and quickly transformed into spinal cord cells which he subsequently injected into rats for observation. He found that the new cells travelled all throughout the damaged spinal column and then enmeshed themselves around the nerve clusters, thereby ensuring that function was restored. Dr Keirstead explained that the new stem cells are “a very high purity population of a particular spinal cord cell type that is lost after the patient is injured”.
Due to the fact that this trial is the very first of its kind there still remain a large number of unknowns to be considered, including whether or not the stem cells will work as well on people as they have in animals and whether there will be any side effects of the treatment. In response to these concerns Dr. Keirstead insists that there are likely to be risks, especially with regards to whether or not it is the right cell sector to target. He cautions those eager to receive the treatment to be patient. Even so, some critics of Dr. Keirstead have criticized him for pushing the treatment too quickly, although it will be monitored and regulated, naturally, by the FDA when it enters the human trial phase.
Despite all criticism and support on both sides Dr. Keirstead realizes that there remains a chance that the treatment won’t work in humans or may never be allowed to be tested on human subjects as approximately two-thirds of all new treatments will never make it past second-phase testing.
Stem Cells and HIV
Research conducted by the UCLA AIDS institute alongside associated colleagues has shown that stem cells present in human blood could be genetically redesigned into cells that would be capable of hunting down and eliminating HIV-infected cells. This process could also eventually be used to target and treat a wide range of chronic diseases spread by viruses.
The UCLA study, which was published on December 7th, 2009 in PLoS ONE, an online journal, provided proof of feasibility that existing stem cells harvested from the human body could be genetically modified into what could be considered a genetic vaccine. In this way such an approach to cells can effectively be used to modify or engineer the body’s natural immune system and the fundamental T-cell response in particular where any AIDS-related treatments are concerned according to the lead investigator on the team, Scott G. Kitchen, who is also the assistant professor of medicine at the David Geffen School of Medicine at UCLA.
These treatments can be targeted at a range of viruses that cause chronic diseases and even different types of tumors. Mr. Kitchen stated that the studies carried out by his team lay the foundation for further therapeutic developments that involve restoring damaged immune systems. They found that the engineered stem cells developed into mature, multi-purpose HIV-specific cells that were able to target cells specifically containing HIV proteins. The stem cells that were engineered by the team were implanted into mice for study, thereby allowing them to observe how the cells would react in a living organism. The team’s research also revealed that HIV-specific T-cell receptors need to be specifically matched to individuals in the same way that organs must be matched to transplant patients.
In a similar case a transplant of stem cells allowed a German AIDS patient to cease taking the medication he had be taking for the past ten years. The patient received stem cells from a donor with a rare gene variant that is already known to resist AIDS. Researchers also reported that the patient’s leukemia was also cured as a result of the transplant.
The donor who gave the stem cells was in the 1% of Caucasians that have the variant gene which does not have the section known as CCR5 – the section that helps the AIDS virus to enter a cell. German doctors worked on the premise that, by transplanting the donor’s stem cells into their patient, the process would rebuild both his blood cells and immune system so that they would be without the CCR5 section. As a result of the experiments researchers may well have found new ways of controlling the HIV virus so that patients would no longer have a life-long dependence upon medication should they become infected.
The next stage for Kitchen’s team is to determine whether or not such a procedure will work in the human body as well as extending the potential range of viruses against which such an approach might be used. Early results of the study indicate that the approach could well be effective in combating AIDS as well as a range of other viral diseases.