6) Inkjet printers to print new skin

Ever wondered if inkjet printers could be modified to print anything other than your notes or homeworks? Well, now they can!

Researchers at the Armed Forces Institute for Regenerative Medicine's Wake Forest lab have successfully modified an inkjet printer to dispense living tissue directly to wounds, accelerating healing for areas of skin loss such as in burns. A burn wound is not flat, there are deeper wounds as well as shallow wounds which need to be filled in with different skin cells known as fibroblasts and keratinocytes. A camera scans the patient's body, using a laser to create a 3D map of the wound. The computer then tells the printer where to print, and which cell to use. In an inkjet printer, the bubble of ink formed is roughly the same size as a cell, allowing single cell precision.

A fibroblast is a type of cell that synthesizes the extracellular matrix and collagen, the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals. 

5) Sperm cells grown from scratch

Takuya Sato and his colleagues at Yokohama City University, Japan, extracted germ cells (cells that gives rise to gametes) from the testes of newborn mice that had not yet begun producing sperm. This was placed into an agarose gel soaked in nourishing chemicals and hormones such as fetal bovine serum and testosterone. The mice had been genetically engineered so that a protein only present in fully grown sperm cells would turn green. One month later, the team spotted that almost half their samples had turned green. The sperm were then fused with eggs to create healthy embryos, which were implanted into females to produce healthy offspring which were able to mate and give birth to their own pups.

Another similar study took place in Kyoto University, again, Japan where a research team was able to turn a mouse embryonic stem cell into sperm precursor cells (also known as primordial germ cells). The embryonic stem cells were cultured in cocktails of growth-factors and proteins, which lead to epiblast-like cells that could be used to create primordial germ cells. These were then implanted into the testes of male mice, where they further matured into sperm cells.

If these technique can be repeated with human sperm, it may lead to new methods of treating infertile men.

4) Synthetic Veins for coronary artery bypass

A coronary artery bypass surgery treats the severe narrowing of the arteries that supply our heart with blood and oxygen by bypassing a blockage. It relieves the chest pain caused by angina and to minimise the risk of a myocardial infarction (a heart attack). Just like any other muscle in the body, the heart requires a blood supply for respiration to produce ATP, and for the muscles to contract. This is supplied by the right and left coronary arteries. The inner walls of the arteries can be damaged due to factors such as high cholesterol, high blood pressure and smoking, which leads to a build up of fatty deposits on the inner wall, reducing blood flow and the narrowing of the lumen. This is known as atherosclerosis. Once a coronary artery has been blocked, some areas of the heart become deprived of oxygen, causing the tissues to die, causing a heart attack.

Usually, a heart bypass surgery involves taking a 'healthy' blood vessel from the arms or the legs and grafting it around the affected areas of the coronary arteries. However, in February 2011, a group of research scientists from East Carolina University, Duke University, Yale University and Humacyte Inc. developed a method for using human muscle tissues to create human blood vessels in the laboratory that showed excellent blood flow and resistance to blockage and other complications when tested on animals.

http://www.dailymail.co.uk/health/article-1352956/DIY-veins-transform-heart-surgery-help-kidney-patients.html

http://www.telegraph.co.uk/health/healthnews/8298911/Human-blood-vessels-grown-in-the-laboratory.html

3) Artificial heart

On June 9th 2011, Matthew Green, a 40-year-old father became the first UK patient to receive a portable artificial heart implant. The six hour surgery was carried out at Papworth Hospital in Cambridge. This allowed blood to be pumped to his vital organs until a suitable donor heart was found and temporarily eliminated Mr. Green's symptoms of heart failure.

The heart was a plastic device designed to replace Mr. Green's ventricles, and was fitted by surgically removing the actual ventricles, with plastic tubes to replace the valves. The device is then plugged into the plastic valves to complete the artificial system. There is a tube going through the skin (pictured above) which sends pulses of air into two balloon-like sacs in the artificial ventricles which acts as the contractions of the ventricular muscles for ventricular systole. This is powered by a driver unit which weighs around 7kg.

Mr. Green is being closely monitored for risk of his body rejecting the device and the risk of infection. 

2) Genes from algae may cure blindness

Three blind mice, three blind mice,

See how they run, see how they run,

They all ran after the farmer's wife,

Who cut off their tails with a carving knife,

Did you ever see such a thing in your life,

As the three blind mice?

Well, not anymore, because in April 2011, a blind mouse had a gene taken from an algae inserted into it's retina which restored it's sight. The gene taken from the algae encodes a light-sensitive protein, and the expression (the process by which information from a gene is used in the syntheses of a functional gene product) of it was targeted to a subset of retinal cells.

The human eye works by the photoreceptor nerve cells on the inside back wall of the eye that converts light rays (photons) into electrical impulses by changing the cell's membrane potential. The impulse is then carried along the optic nerve and into the brain where the image is perceived. With an ageing global population, the number of people with blindness will continue to increase. Today, there are around 15 million people worldwide with some form of blindness (e.g. retinitis pigmentosa or age-related macular degeneration) which are damages to these photoreceptors.

The technique used at the Institute of Genetic Medicine at the University of Southern California, succeeded in restoring the ability for the mice to sense light and dark, and clinical trials on humans could begin in 2 years.

1) Severe Combined Immunodeficiency and Gene Therapy

Jack Crick, a 7 year old boy with a rare condition known as Severe Combined Immunodeficiency (SCID) or 'bubble boy' affecting 1 in 200,000 was treated on 25th August 2011. SCID is caused by a mutation in a number of genes, most commonly in the protein required for the development and differentiation of T and B lymphocyte cells. The second most common involves a mutation that compel the body to make abnormal enzymes called adenosine deaminase, leading to a reduction in immune cell production.


Gene therapy is used to treat SCID by removing cells from the patient's bone marrow. A viral vector is used to introduce a functioning copy of the faulty gene and the cell is re-transplanted back into the patient. This treatment is an improvement of the traditional method involving a bone marrow transplant as there is no risk of the patient's body reacting to donor material, causing a disease.

According to follow up studies published in 'Science Translational Medicine' the treatment had a success rate of 4 out of 6 for those with Adenosine Demaninase-Deficient SCID, and 10 out of 10 for those with X-linked (B and T lymphocyte) SCID.

The major drawback of the therapy is that it may activate an oncogene, which cause cancer. In the London trial for gene therapy, 1 out of the 10 patients treated for X-linked SCID developed Leukaemia. However, it is still unclear why this occurs. Currently, new retroviral and lentiviral vectors (tools used to deliver genetic material to cells) are being researched and developed to reduce the risk of leukaemia.

Viral Vectors

A virus is an infective agent that typically consists of a nucleic acid molecule within a protein coat. As a part of their replication cycle, all viruses attack host cells and introduce their own genetic material containing 'instructions' on how to produce more copies of the virus. Some viruses physically insert their genes into the host's genome, and these are used as viral vectors. The disease-causing gene is removed from the virus and replaced with genes encoding the desired effect depending on the treatment.

Some risks of using viral vectors are that...

• the virus may affect healthy cells as well as cancer cells
• the gene may by inserted into the wrong location of the DNA causing harmful mutations (this is what most likely occured for the X-linked SCID patients developing leukemia. The 'hematopoietic stem cells' were transduced (transferring of DNA) with a corrective transgene (exogenous gene introduced into the genome of another organism) using a retrovirus).

Ethics

As with any great medical study, there are ethical issues involved. Religious groups argue that scientists are 'playing god' by altering the way 'God' created us as gene therapy to enhance basic human traits such as height, intelligence and athletic ability is being investigated. There are also concerns that gene therapy may only be available to those who are wealthy due to it's high cost, creating a greater divide in society according to wealth.

More ethical issues concerning gene therapy can be found here.

More on virus vectors can be found here.

A kick-start to 2012 with some quick reflections on 2011

Happy Holidays and a Happy New Year!

This week, I will be sharing some highlights of 2011 including health related news stories, published studies and articles taken from a variety of sources such as the NHS, BBC and New Scientist website (links below).

Sit back, relax and have a great 2012 (Without forgetting to work hard).

http://www.nhs.uk/news/Pages/NewsIndex.aspx
http://www.bbc.co.uk/news/health
http://www.newscientist.com