Opt-out organ donation in the UK by 2020
This autumn parliament is going to vote whether an opt-out organ donation system is going to be adopted in England. The new legislation also called “Max’s law” after Max Johnson, a receiver of a heart donation, would follow the example set by Wales, where opt-out organ donation was implemented in 2015.
Opt-out organ donor systems assume that a person is happy to be an organ donor unless they opt out of the donation via the NHS organ donor registry or an NHS app that will be introduced alongside the new legislation. The opt-out system that the English government is voting on is a so-called “soft opt-out”, meaning that the family of the deceased has the option to overrule the assumed organ donor status if they are convinced that their loved one would not want to be an organ donor. Currently, England relies on people actively opting in to be registered as an organ donor, but politicians argue that the new opt-out strategy will lead to an increase in organ donations.
In 2017 411 people died in England before receiving an organ and over 5000 people are currently on the waiting list for a transplant. It is not entirely clear if soft opt-out systems are the solution to low organ donor numbers. In the first two years since implementing the soft opt-out organ donor system, Wales has not seen an increase in organ donations, however experts point out that the transition might take a while. In Spain, where opt-out organ donation was implemented in 1979, donor rates only began to increase after 10 years when a new national transplant organisation was founded to coordinate the donation and transplantation process.
Sweden, where opt-out organ donation was implemented in 1996 still has one of the lowest organ donation rates in Europe, highlighting the need to not only change opt-out legislation but also implement structural changes, as well as raise public awareness. In countries like Austria or Singapore, a hard opt-out means that families can’t overrule an assumed organ donor status and, in these countries, a rise of up to 25% in organ donations has been reported.
Birds see just like us
Researchers found that songbirds perceive colour in a similar way to humans by grouping similar shades into categories. The study by a team of researchers from Duke University in North Carolina was published in Nature and shows for the first time that birds are capable of something called “categorical perception”.
Categorical perception means that the birds were able to distinguish categories, in this case, whether a disk falls into the red or orange category along a continuous colour spectrum. The researchers trained female zebra finches to flip over two-coloured paper disks to reveal food. Single colour discs could also be flipped over but didn’t lead to a reward.
Eight colours on a spectrum from orange to red were used to mimic the colourations of male zebra finch beaks. In nature, female zebra finches prefer red coloured beaks, as they imply a higher amount of carotenoid. Carotenoid cannot be produced by the birds themselves but needs to be taken up via food, therefore indicating a superior foraging success. Increased carotenoids may also imply a potentially superior immune system. The female birds were especially respondent to two coloured disks containing colours from opposite end of the orange-red spectrum, and less responsive when the colours were closer together on the spectrum.
The birds demonstrated that they were able to lump colours together into either the red or orange category, implying that the male zebra finch’s beak does not necessarily have to be a perfect shade of red to be preferred by the females. Interestingly, the study also suggested that categorical perception is not dependent on how well the eye perceives colour, but how the signal is processed by the brain. Earlier studies have highlighted that language is not essential to study categorical perception, as primates and infants have shown to be capable of distinguishing colours.
Categorical perception has never been shown in non-primates before and continues to be far more widespread than previously thought, having been implicated, e.g. in facial identity recognition and frog and cricket calls.
Breathe in – bioengineered pig lung transplants
Researchers from the University of Texas Medical Branch (UTMB) in Galveston, US, have successfully transplanted a bioengineered lung into a pig. The lung was created using a donor scaffold and cells from the pig that was to receive the transplant and grown in a bioreactor before being transplanted into the animal. Most excitingly, the lung was not rejected and continued to develop within the animal, marking an important step towards potential use of bioengineered lungs in humans.
To create the bioengineered lung researchers removed all cells and blood vessels from a pig donor lung, leaving behind a protein scaffold onto which they planted cells from the pig that was about to receive the transplant. Using the pig’s own cells reduces the likelihood that the body rejects the organ. In this way, the lung was grown inside a bioreactor over 30 days and stem cells and growth factors were used to help the development of the blood vessel system within the lung tissue. After the transplant, CT and MRI scans, as well as gene expression measurements were used to confirm that the lung tissue and associated blood vessels continued their development within the recipient pig. At the predetermined endpoint of the study at 2 months, the lung had not been rejected and seemed to develop normally. The researchers cautioned that oxygenation of the animal couldn’t be evaluated as the lung tissue wasn’t fully matured at 2 months, but the procedure has been successful in four pigs.
Currently, the demand for lung transplants vastly outnumbers the supply and even when a suitable donor lung is found, it often cannot be matched for size. Bioengineered lungs would, therefore, offer an alternative for patients suffering from diseases such as cystic fibrosis, pulmonary hypertension, chronic obstructive pulmonary disease or idiopathic pulmonary fibrosis. While there are still issues with bioreactors for human use, experts are positive that the first bioengineered human lung might make an appearance within 5 to 10 years.
Written by Charlott Repschlager