Inhaled nebuliser - blazing new trails in medicine

By Carol Aloysius

Injections could be a thing of the past as scientists prepare to 'breathe vaccines"

A team of researchers at Murdoch Children's Research Institute and Monash University have developed a novel way of turning a liquid vaccination into an aerosol form against the flu.

In a world first study, the researchers used a plasmid DNA vaccine and the result was a novel way of aerosolising sensitive biomolecules via the use of very small but powerful sound waves. The study was led by Sri Lankan born Dr Anushi Kulasiri Rajapaksa.

She told the Sunday Observer that the researchers in their study had used this technology to provide a strong immune system after inhalation of the DNA vaccine in sheep - a pre-clinical model - as they have similar lung structure and physiology to humans. She said the study showed that there were protective antibodies in the sheep's blood at a level considered significant by the World Health Organisation.

"The nebuliser device which is no bigger than a matchbox, is already in mobile phones. What researchers did was to find a new use for it", she said.

The lung, she noted, is an attractive site for delivery of gene therapy and DNA vaccine agents since it is accessible, has a large surface area and is highly cellular and vascularised to facilitate transfection.

Pulmonary delivery via inhalation is non-invasive and allows for pain-free access where potential systemic side effects are minimised.

Replacement of the parenteral route with alternative modes of administration would mitigate vaccine safety issues and the requirement for skilled personnel, amongst the many other issues associated with injections."

She said that when they applied electricity to the device, a miniature sound wave travels on the surface of the device.

This wave interacts with the medication to agitate it so much so that the surface tension of the fluid is broken up to form a fine mist of particles. "The timing of these events happens so fast that the DNA molecules in solutions have no time to stretch, and so, there is little to do damage to their structure.

"This development holds a lot of promise for a replacement to vaccine injections which are associated with safety concerns in developing countries, requiring expensive and specialised handling, refrigeration and staff training that many countries cannot afford", she pointed out.

Benefits

Current vaccines often induce inflammation, causing pain, requiring monitoring by health care workers and resulting in people's reluctance to seek vaccination. Hence the research team tried to re-engineer vaccine administration with our respiratory nebuliser for plasmid DNA vaccine delivery, Rajapaksa said.

Asked how long it would take for a DNA based vaccine to be produced, she said, "As little as two weeks - a critical improvement in the face of a pandemic".

In addition to the short time it takes to be developed, the nebuliser has other benefits.

The nebuliser technology can be made portable and only requires batteries for operation. "There is high potential for this work to be used for mass vaccination programs especially in developing countries with limited resources." Rajapaksa said.

How it operates

"It works as droplets containing the vaccine are inhaled and deposited on the surfaces of the lung. Once the DNA of the vaccine is introduced into a person's cells, those cells produce 'antigen' proteins.

The immune system is trained to attack the disease by producing antibodies against these antigen proteins. There is no inflammation when using DNA vaccines, and no use for needles for injection, making it much easier for a person to tolerate," Rajapaksa explained. She said that inhaled immunisation using the nebuliser was especially suitable for lung related afflications such as influenza and potentially for systematic diseases such as Malaria with entirely new DNA vaccines.

"Pulmonary delivered gene therapy promises to mitigate vaccine safety issues and reduce the need for needles and skilled personnel to use them", she thus reiterated.

Challenges

However, not all polyplexes (nor lipoplexes) retain biological efficacy after aerosolisation, with some commonly used synthetic polymers such as polyethylenimine (PEI) considered to be cytotoxic.

Effective delivery via the pulmonary route therefore requires the aerosolised DNA to be internalised into the target cell via endocytosis, avoiding degradation either during delivery or via exposure to lysosomal or cytoplasmic nucleases, and subsequent transcription and translation to produce the desired gene product.

In such devices, the SAW is localised to the substrate surface, and most of the energy input into the system is near the surface and transferred into fluid resting upon it with minimal loss. As such, SAW nebulisation requires only about 1 W of power to operate, significantly less than conventional bulk piezoelectric ultrasonic radiators and convenient for use in handheld devices, she said.

Aim

The aim of this study was to demonstrate the feasibility of SAW nebulisation as an aerosol delivery platform for DNA delivery to the lungs in a large animal model.

In reply to a question posed by the Sunday Observer on the reason she embarked on this study, she said: "As a mother of a two year old son, I found it hard to bear the thought of going through routine vaccination processes for my son due to the discomfort he experienced.

"I wondered about ways that would avoid the inconvenience and yet be an effective therapy. And better yet, make it fun and easy for a child. I hope that with this work we are one step closer to realising the dream on inhaling vaccines to safeguard us against potential infections."

Major cause of blindness linked to calcium deposits in the eye

Microscopic spheres of calcium phosphate have been linked to the development of age-related macular degeneration (AMD), a major cause of blindness, by UCL-led research.

AMD affects 1 in 5 people over 75, causing their vision to slowly deteriorate, but the cause of the most common form of the disease remains a mystery.* The ability to spot the disease early and reliably halt its progression would improve the lives of millions, but this is simply not possible with current knowledge and techniques.

The latest research, published in *Proceedings of the National Academy of Sciences*, has implicated tiny spheres of mineralised calcium phosphate, 'hydroxylapatite', in AMD progression. This not only offers a possible explanation for how AMD develops, but also opens up new ways to diagnose and treat the disease.

AMD is characterised by a build-up of mainly protein and fat containing deposits called 'drusen' in the retina, which can prevent essential nutrients from reaching the eye's light-sensitive cells, 'photoreceptors'.

Photoreceptors are regularly recycled by cellular processes, creating waste products, but drusen can trap this 'junk' inside the retina, worsening the build-up. Until now, nobody understood how drusen formed and grew to clinically relevant size.

The new study shows that tiny calcium-based hydroxyapatite, commonly found in bones and teeth, could explain the origin of drusen.

The researchers believe that these spheres attract proteins and fats to their surface, which build up over years to form drusen.

Through post-mortem examination of 30 eyes from donors between 43 and 96 years old, the researchers used fluorescent dyes to identify the tiny spheres, just a few microns - thousandths of a millimetre - across.

"We found these miniscule hollow spheres inside all of the eyes and all the deposits that we examined, from donors with and without AMD," explains Dr Imre Lengyel, Senior Research Fellow at the UCL Institute of Ophthalmology, who led the study.

"Eyes with more of these spheres contained more drusen. The spheres appear long before drusen become visible on clinical examination.

"The fluorescent labelling technique that we used can identify the early signs of drusen build-up long before they become visible with current methods.

The dyes that we used should be compatible with existing diagnostic machines. If we could develop a safe way of getting these dyes into the eye, we could advance AMD diagnoses by a decade or more and could follow early progression more precisely."

Some of the mineral spheres identified in the eye samples were coated with amyloid beta, which is linked to Alzheimer's disease. If a technique were developed to identify these spheres for AMD diagnosis, it may also aid early diagnosis of Alzheimer's. Whether these spheres are a cause or symptom of AMD is still unclear, but their diagnostic value is significant either way. As drusen are hallmarks of AMD, then strategies to prevent build-up could potentially stop AMD from developing altogether.

"The calcium-based spheres are made up of the same compound that gives teeth and bone their strength, so removal may not be an option," says Dr Lengyel.

"However, if we could get to the spheres before the fat and protein build-up, we could prevent further growth. This can already be done in the lab, but much more work is needed before this could be translated into patients."

"Our discovery opens up an exciting new avenue of scientific research into potential new diagnostics and treatments, but this is only the beginning of a long road." says Dr Richard Thompson, from the University of Maryland School of Medicine, USA.

MNT

UK:

Cigarettes likely to be sold in plain packets

Packaging will be allowed to have a brand name, but little else apart from health warnings

The Government has finally decided that cigarettes are to be sold in standardised packages in England.

Jane Ellison, the public health minister, told the Commons that regulations would be put to a free vote before Parliament breaks up for the general election in May.

The Government was thought to have backtracked on its initial support for the idea after intense lobbying by Big Tobacco.

The free vote will allow Tory MPs against the idea to register their opposition.

Packs will be allowed to have a brand name and a variant name but little else apart from health warnings. Ms Ellison said rules to enforce plain packaging were "a proportionate and justified response to the considerable public health harm" that results from tobacco.

"Smoking... is a major cause of cancer, heart and respiratory disease and almost 80,000 people in England alone die every year from ill health caused by smoking," she said. "It places an enormous strain on the NHS. The regulations will come into force in May next year if MPs agree."

Deborah Arnott, chief executive of the anti-smoking charity Ash, said she was "delighted" the Government has "resisted pressure" from the tobacco industry.

"Every day hundreds of children start to smoke. Standard packs mean that the tobacco industry cannot use glitzy packaging to help addict the next generation," she said, adding that the number of smokers had fallen dramatically in Australia since it became the first country in the world to introduce plain packaging.

Luciana Berger, Labour's shadow public health minister, also welcomed the decision, although she added that the Government had "inexcusably" delayed making it by about a year.

The Independent

Women may experience more pain during childbirth if their partner is present

Researchers have suggested women who avoided closeness in their relationship experience more pain if their partner is present For many, the role of the expectant father is to provide comfort, reassurance and assistance to their partner at childbirth.

A new study however, has suggested they may be better off considering to stay well away from the delivery room as their presence could make the process of giving birth more painful.

Research by psychologists found that while for some the presence of their partner made no difference in pain experienced, for women who avoid intimacy in their relationship, it made the experience more painful.

To carry out the study, rather than intruding on women giving birth, researchers gave 39 women a "pinprick" laser pulse while their partner stood close by.

Prior to the study, the women had also been given a questionnaire to measure whether they avoided or sought closeness in relationships.

The researchers monitored the electrical activity in the brain after the moderately painful pulse was administered, while the women were also asked to rate its intensity.

The experiment was then repeated while their partner was not present.

The researchers have said they discovered that in many cases the pain experienced felt worse when their partner was present.

According to a report, the more participants avoided closeness in their relationship, the more pain they experienced while their partner was present. Those who sought intimacy however appeared to experience no significant effect if their partner was present.

Senior author Dr Katerina Fotopoulou, of UCL Psychology and Language Sciences, said: "Overall, this study suggests that partner support during pain may need to be tailored to individual personality traits and coping preferences.

"Individuals who avoid closeness may find that the presence of others disrupts their preferred method of coping with threats on their own. This may actually maintain the threat value of pain and ultimately heighten individual's pain experience.

"This hypothesis was further supported by the finding that electrical activity in the brains of these individuals was influenced by partner presence in the same way as their subjective pain report and particularly in areas typically associated with processing bodily threats."

Dr Fotopoulou said previous research had shown women who prefer to have partners present during childbirth make less use of painkillers after labour.

However, the different results of this experiment "could suggest that some of the previous results may not necessary relate to the sensation of physical pain, but the broader meanings and needs associated with childbirth."

Dr Fotopoulou said: "The physical and psychological nature of labour pain may simply be different than other types of pain.

Future studies could test how having a partner present during labour affects the pain felt by women who tend to avoid closeness in relationships."

- The Independent