Sep - 27 Bone marrow stem cells used to treat strokes in mice - By Charlotte Maden

A group of US researchers have found that injecting human stem cells derived from bone marrow into the brain after it has suffered a stroke can alleviate symptoms. The research was carried out at the Center for Gene Therapy, Tulane University, New Orleans, and reported in Proceedings of the National Academy of Sciences.

Strokes are characterised by reduced blood flow to the brain caused by a blockage or bleed, thereby starving the brain of blood. An immune response ensues, during which healthy tissue is attacked and nerve damage is caused. Stroke is the third most common cause of death in the UK, and also the leading cause of severe disability. Every year 150,000 people in the UK suffer from a stroke - mostly people over 65 - but it can affect people of all ages.

During the study, a stroke-like state was simulated in six mice by blocking their carotid arteries and therefore halting the flow of blood to the brain. The researchers then injected the mice with human mesenchymal stromal cells (bone marrow stem cells), and found that neuron damage was reduced by up to 60 per cent.

Instead of generating new cells as expected, the team revealed that the cells exerted the effect by changes in gene expression, resulting in production of biochemicals which reduced inflammation. After the blood flow was stopped, 586 genes were more active in untreated mice. In mice injected with stem cells, 10 per cent fewer of these genes were more active. This suggests that those genes are likely to be involved in the immune response. In addition, the motor responses of the treated mice were dramatically improved, shown by better performances in movement, cognitive and behavioural tests than untreated mice.

Professor Darwin Prockop, co-author of the study, said that it 'provides for the first time a molecular explanation of how adult stem/progenitor cells can ameliorate ischaemic (reduced blood flow) damage to the brain'. He also highlighted that 'the fascinating thing was the cells were talking to each other - human cells and mouse cells' and that 'the human cells specifically turned down immune and inflammatory responses'.

The team is currently building a facility of sufficient standard to produce stem cells for use in patients, and is planning further testing of the technique in animals for efficacy and toxicity. Following this, human clinical trials should begin in the hope that stem cells can be used to treat strokes in humans in the future.

Sep -28 Low-cost hereditary breast cancer test could be available by next year - By Ailsa Taylor

By next year it could be possible to sequence the entire coding regions of BRCA1 and BRCA2 genes, which can put women at risk of developing hereditary breast cancer, for as little as £10, Professor Graham Taylor, Head of Genomic Services at Cancer Research UK, told delegates at the British Society for Human Genetics last Wednesday. 'Next generation' sequencing technology could slash current prices by up to 99% and is poised to deliver groundbreaking advances in genetic diagnosis across a whole spectrum of inherited conditions, says Professor Taylor, who is trialling the approach in collaboration with colleagues from Yorkshire and Wessex Regional Genetics Laboratories.

When the Human Genome was first sequenced in 2003, it was an expensive and labour-intensive process, taking some eight years to complete and costing the UK taxpayer in the region of £3 billion. But in the five years since, cheaper, easier and faster sequencing techniques have been developed, allowing much larger stretches of DNA to be sequenced at just a fraction of the cost.

Professor Taylor said: 'The emergence of next generation sequencing technologies has largely been spurred on by the field of genomics, where scientists have been trying to unravel the genetic basis of many common diseases, such as diabetes and cancer, by scanning the entire genomes of thousands of individuals at a time. What we've done is take this technology and see if it can be used to look for gene changes in a tiny fraction of the genome, for example a single gene.'

It is estimated that 5-10% of breast cancer patients have an inheritable form of breast cancer due to a mutation in one of two genes known as 'BRCA1' and 'BRCA2'. In their 'normal' state, these genes protect against cancer within the cell. However, women who carry a mutation in either of the genes have up to an 80% chance of developing breast cancer during their lifetimes. Currently, women can be tested for defective copies of the two genes, but this involves full genetic sequencing, which can take weeks and is very expensive.

Next generation sequencing technology allows several samples of DNA to be screened at a time, meaning that hundreds of diagnostic samples can be sequenced in one week, compared to the 18-week turnaround time associated with traditional methods.

Pilot studies are already underway to examine the potential for next generation sequencing technology to be used to diagnose a range of hereditary cancers, with results expected early next year.

Sep - 29 Anti-depressants may be linked to male infertility - By Antony Blackburn-Starza

Anti-depressants may be linked to male infertility, say researchers at the Cornell Medical Center in New York. Results of a study reported in the New Scientist this week reveal that males taking anti-depressants - also known as selective serotonin reuptake inhibiters (SSRIs) - could be damaging their sperm. The study was performed by Peter Schlegel and Cigdem Tanrikut on 35 health male participants who were given paroxetine, which is marketed as Paxil or Seroxat by GlaxoSmithKline. After four weeks of taking the medication, it was found on average the proportion of sperm that became fragmented (damaged) nearly doubled, rising from 13.8 percent to 30.3 percent.
Sperm damage has been linked to male infertility and it is believed may also contribute to a decrease in embryo viability, although in itself the results do not mean males taking SSRIs will encounter fertility problems. In an abstract of the study made available to Reuters, the authors said: 'The fertility potential of a substantial proportion of men on paroxetine may be adversely affected by these changes in sperm DNA integrity.' In 2006, nearly two million prescriptions for peroxetine were issued.
Doctors have warned that the study should not prevent individuals with depression from seeking or stopping medical intervention. 'Patients shouldn't stop their antidepressants, but those who are depressed and experiencing fertility difficulties may wish to discuss this with their GP,' said Steve Field, chairman of the UK's Royal College of General Practitioners. Other experts have questioned the significance of the findings because, although they may seem alarming, the clinical significance may be low. Dr Allan Pacey, Senior Lecturer in Andrology at the University of Sheffield, said that further research is needed. 'It is a shame that the authors appear not to have conducted a randomised controlled trial which would be the most scientific way to investigate the drugs' effects, but I agree that the results are of concern and need to be investigated further,' he said.
Glaxo told Reuters that it was reviewing its own findings on the drugs, as the study was not mandated by the company. A Glaxo spokeswoman said: 'These medicines remain an important option, in addition to counselling and lifestyle changes, for treatment of depression and this study should not be used to cause unnecessary concern for patients.' Other medical experts have highlighted that risks are in inherent part of taking medication. '[Anti-depressants] are powerful drugs, so in a sense it is no surprise that research is discovering more about their impact on the body,' said Dr Andrew McCulloch, of the Mental Health Foundation.