Stem Cell Thearpies

Stem Cell Thearpies

Stem cell treatments are a major development in genetic and medical history. Stem cells hold the ability to treat many debilitating illnesses although their uses in treatments raise many ethical debates.

Firstly, let’s define a stem cell. A stem cell is an unspecialised cell that can form specific cells such as a heart, lung or tissue cell. A stem cell is a template for all cells. There are two types of stem cells: pluripotency stem cells and adult stem cells.

Pluripotency stem cells are found in embryos and are therefore named embryonic stem cells. Pluripotency stem cells have the ability to form vast numbers of more specific cells in an embryo, allowing embryos to grow and develop into babies. Because embryonic stem cells hold the ability to form a wide variety of cells, they hold great potential when used in stem cell treatments. However, not all people are in favour of using stem cells in medical treatments.

The embryonic stem cells are derived from fertilised human eggs but are destroyed in the process of Somatic Cell Nuclear Transfer or SCNT.

The process of SCNT involves removing the nucleus of the embryonic stem cell and injecting a nucleus from a different cell into the stem cell. The embryonic stem cell injected with the nucleus from another cell can then be cultivated to regrow the cells from which the nucleus was extracted from. The stem cells grown with the injected nucleus can then be used to replace damage cells. This makes regrowing entire organs and spinal cord tissue possible. This technique was first published by Harvard University in 2008. Some people may find this distressing as they believe SCNT is destroying potential human life.

However, adult stem cells can also be used in stem cell therapy. An adult stem cell is a tissue specific stem cell and can be found in skin, bone marrow, hair follicles and many other sites around the body. Unlike the embryonic stem cells, they are only able to reproduce a specific cell, as the name suggests. For example, an adult stem cell found in the skin can only reproduce to make other skin cells.

Scientists have discovered a technique to make adult stem cells behave like embryonic stem cells. This is called induced pluripotency or iPS. The iPS stem cells have been genetically modified to mimic a pluripotent embryonic stem cell. This is done by using a virus to convert the adult stem cell to behave like an embryonic stem cell and express the genes needed to form the new cell. In 2010, scientists at Standford University have been able to turn fat cells into iPS cells without the use of a virus, making the process of iPS a lot safer and simpler.
The iPS cell treatment is not as controversial as embryonic stem cell treatment but yield the same results, therefore making it a more suitable option in medical treatments.

By using stem cell therapy, illnesses and injuries that may be life threatening or permanently debilitating could one day be treated. With advancing medical and genetic technology, many conditions that were previously thought to be incurable, may well be treatable with stem cell therapies.

Pros and Cons of Designer Babies

Pros and Cons of Designer Babies


Pros:
1.) Designer babies could prevent genetic diseases in babies.
2.) Baby can look and act the way you want it to- hair color, eye color, brains, and athletic ability.
3.) They could, given the knowledge and resources, create an immortal child.
4.) You could see what problems could come for the baby in the future.

Cons:
1.) Everyone could start to look the same, which would cause loss of diversity and culture.
2.) Some people would overuse and abuse their privileges, trying to create the worlds only "genius" or the "ultimate" athlete, parents could choose the life of the child, taking away free will given by God.
3.) It would only help the rich, people who could afford it, and most of the people with genetic diseases in like Africa couldn't afford the help, when they need it more.

Down Syndrome

Down Syndrome

Down Syndrome is a chromosomal condition characterized by the addition of either half or whole of an extra chromosome. Chromosomes are strands of DNA (deoxyribonucleic acid) and proteins which are present in every cell of the body and make up our individual genetic material. Down Syndrome affects 1 in every 800 babies born. The extra genetic material can impair the mental and physical development in a child although the extent of this impairment varies from patient to patient (Gavin, 2012). With current research continuing, the possibilities of minimizing the risk of Down Syndrome will increase.
Down Syndrome is the most common chromosomal disorder in the world. Our cells divide in two ways, firstly is ordinary cell division which is called mitosis in which our body needs to grow. Secondly is in the ovaries and testicles where meiosis occurs. This cell division consists of one cell splitting into two creating sperm and egg cells (refer to figure 1).

Normally during conception 23 chromosomes from the mother and 23 chromosomes from the father are inherited, totaling to 46 chromosomes, and these chromosome contain genetic information. Recent research suggests that in the majority of Down Syndrome cases there is an ovarian nondisjunction during meiosis and he child will obtain an extra chromosome 21 for a total of 47 chromosomes rather than 46 as mentioned earlier (refer to figure 2). A possible cause for this is maternal age although the exact cause is not yet known (Gavin, 2012).

                                                Figure 2: Down Syndrome Chromosomes

The life expectancy of an individual with Down Syndrome is usually around 50 years of age. This is quite low due to almost every system in their bodies being at risk from the effects of Down Syndrome (Schoenstadt, 2012). The exact effects of Down Syndrome are still not known as chromosome 21 codes for approximately 360 proteins although there are some common health problems, such as decreased brain size, congenital heart disease and lens defects. Individuals with Down Syndrome also suffer from increased purine levels which can lead to mental retardation and immune deficiencies. Purine is an organic compound that contributes to the contents of RNA and DNA. As well as health problems there are some physical attributes that are common in Down Syndrome patients for example slanted eyes, shorter neck and shorter limbs (Cunningham, 2008).
There are treatment and therapies available for Down Syndrome patients including physiotherapy to help strengthen muscles, surgery for heart disease  and regular check ups and screening to prolong the life of the individual (Cifra-Bean, 2012). Research in the field of genetics is very promising although it must only be considered in the future as the genes need to be identified and their function be determined before any radical medical procedures are recommended. Interactions between genes can also be a key factor to help minimizing Down Syndrome (Cifra-Bean, 2012).
It is a very promising time in research in Down Syndrome as the advent of the completion of the human genome project is more understood and practiced than ever before. Future research could help improve life expectancy, symptoms and possibly even help repair the chromosome 21 in this devastating chromosomal disorder.

Changing the Gentic Code

Changing the Gentic Code

All life possesses a genome and the nature of that life is determined by it's genome. The genome consists of DNA which is made up of four nucleotides (Adenine, Cytosine, Guanine, Thymine), a series of three of these nucleotides is called a codon (64 codons in total) with each of these codons corresponding to one of the 20 amino acids or one stop codons. These codons are then translated into their respective amino acids until a stop codon is reached. Now what would happen if an organism had a codon that it did not normally have?

                                                            FIG   :  E coli just chiling

In theory an organism with non-naturally occurring amino acids could be made immune to viruses at the very least. Viruses replicate basically by commandeering a cell's ribosome and the other components used for replication.“Viruses depend on the fact that their proteins are encoded by the same codons as those of their hosts”(Young, Discover magazine 2011) If the organism has unnatural codons the viruses are almost certainly not going to have those codons and as such be unable to take over.

A team led by Farren Issacs at Yale University is attempting to answer that question. To do this they have edited the genome of Escherichia coli replacing the E coli's TAG stop codon with TAA another stop codon. First the team identified all 314 TAG codons in E coli, they then created small segments of DNA that had TAA instead of TAG which they mixed into a nutrient rich solution that was swimming with viral enzymes then submerged around a billion E coli in this solution.

The first of two processes MAGE was then used. MAGE or multiplex automated genome engineering, was first used a few years ago and allows bioengineers to do in days what would have previously taken them years. Essentially a specially prepared segment of DNA is placed in a solution with the cell and then electricity is run through the solution. This causes the cell to open pores in it's membrane allowing the DNA inside. Then when the cell next undergoes mitosis it will use this new DNA in the process. The DNA can then be found in the genome of the daughter cells.

MAGE gave the researchers E coli that had some TAA codons, however to create E coli that only had TAA they would have to use another process call CAGE. CAGE or conjugative assembly genome engineering relies on the bacterial form of sex, Bacterial conjugation, where one bacteria transfers genetic material (in this case the TAA codons) to another. The researches separated the E coli into 32 groups then used CAGE until they had a strain with almost entirely TAA codons.

Once the process is complete, the researchers could assign the now unnecessary TAG codon to an amino acid (natural or otherwise) instead of a stop codon. As mentioned before this could make bacteria immune to viruses, (a great thing if that bacteria is used in the production of medicine), what else this could potentially do we can at the moment only speculate. . It should be noted that the E coli seem to suffer no effects from their lack of TAG codons, raising the question what effects the stop different codons have.

DNA methylation

DNA methylation:

 A new approach to modifying cancerous & other diseased cells.


Epigenetics is a fairly new area of genetics, epi- is a Greek prefix meaning above, on or over and epigenetics refers to the study of gene expression other than that of a specific change in the nucleotide sequencing. DNA methylation is a form of epigenetic signature, it is fairly common throughout DNA and is more closely related to cell identity, which is what it sounds like; how’s cells identify themselves. Or for example; how a skin cell, knows not need to produce insulin, while a pancreatic cell knows that it shouldn’t produce pigment. (Health Canal 2012) I won’t dive too deep into the specifics but basically; a methyl group is attached to specific CG sites in the DNA sequence. This is where Cytosine and Guanine are sitting side by side, within DNA. A research paper was published earlier this month in the scientific journal Cell Metabolism titled “Acute Exercise Remodels Promoter Methylation in Human Skeletal Muscle”, the subject of the study being how exercise induces instantaneous methylation changes, subsequently altering gene activity to better burn lipids and carbohydrates within mitochondrial function. The research recruited fourteen young and healthy recruits who were punished on an ergometer for incremental short bursts of exercise – fun. Immediately after the pain, more pain was administered in the form of a muscle biopsy which was taken and the methylation then tested. Another biopsy was taken twenty minutes later to examine the difference in methylation levels, and what do you know, they discovered “that acute exercise induces gene-specific DNA hypomethylation in human skeletal muscle.”
Figure A shows the change in methylation, whereas figure B shows the ratio between the levels of methylation on specific genes.

Barrès and co. believed they made a pretty significant discovery, seeing as epigenetics when it first came about wasn’t seen as an important player in the game of genetics. But what they discovered is that hypomethylation is occurring all the time within our DNA, so it’s not as stable a process as once was believed. Their hopes with this is that this can remove some of the fear around tampering with methylation levels within DNA. In other scientist’s defence, this is a fair call as a methylation imbalance has been linked tumour progression (Baylin et al. 1998).

So how does this mean that we can modify cancerous and other diseased cells? Well Barrès believes that they “have shown, that just by exercising, you, yourself manipulate the DNA of your cells. Our DNA is not as stable and unchangeable as previously thought.” (Health Canal 2012). As I said earlier, cell identity and gene expression has much to do with methylation, so how about telling different cells to heal themselves? Or seeing as the original discovery was in fact to do with methylation caused by exercise, what I we could tell cells that they were exercising when they were performing little or no exercise? I can imagine international pharmaceutical giants salivating at this thought – but it could be put to much better use to by simulating exercise for diabetics who have lost both legs to their diabetes. Or perhaps people with severe depression – exercise and fitness is known to improve the symptoms within these people.
Barrès and co. have hungry eyes at this stage and feel that they have opened the door to a whole avenue of new research, but it is very early days so you shouldn’t be getting too excited about that ‘diet pill’ just yet.