Tag Archives: sheep

Weekly Roundup: Ending the vaccine-autism myth, spider venom for stroke victims, and causes of polycystic ovary syndrome

Welcome to our third weekly roundups. These Friday posts aim to inform our readers about the many stories that relate to animal research each week. Do you have an animal research story we should include in next week’s roundup? You can send it to us via our Facebook page or through the contact form on the website.

  • Studies on the relation between the environment and autism are starting to build, ending the vaccine-autism myth started in 1998. No vaccination has met the criteria of being a cause of autism – although some environmental factors increase the risk two to four times. Our understanding of many of these risk factors has been greatly increased with the help of animal research. For example, mouse research on the relation between maternal immune activation and autism-like phenotypes was later found to be consistent in human populations. Also, links to prenatal exposure to medications with teratogens were investigated in rats and found to be consistent with humans.
  • Spiders venom saves stroke victims: Funnel-web spiders are among the world’s deadliest spiders, but their venom can be life-saving. Since the venom targets the prey’s nervous system, researchers tested whether it could be harnessed to reverse brain damage after a stroke. After traveling to Fraser Island to collect three Darling Downs funnel-web spiders, researchers at University of Queensland and Monash University “milked” the spiders to collect their venom, then isolated a protein called Hi1a — a molecule that closely resembles another known for its protective effect on neurons. The team then synthesized their own version of Hi1a and gave the compound to rats two hours after an induced stroke. Neuron damage was reduced by 80 percent. Eight hours after a stroke, it was still effective in restoring neurological and motor functions by almost 65 percent. The researchers hope to commence human clinical trials in the next few years, pending replication of these initial findings and further research into the molecule.

  • A new study has found that polycystic ovary syndrome (PCOS) may start in the brain, not the ovaries, contrary to previous belief. While the cause of PCOS is unknown, one feature of this syndrome is high levels of androgens. Using a high dose of androgens, PCOS was induced in genetically engineered mice which display a receptor for androgens in specific parts of the body (brain, ovaries, nowhere in the body and a normal control group). Mice with androgen receptors in the normal control group developed PCOS as expected, while those without receptors in the brain and in the entire body did not. Interestingly, mice without androgen receptors in the ovaries also developed PCOS albeit at a lower rate than the control group. These data replicate the finding that high levels of androgens are implicated in the development of PCOS. More importantly, they highlight that it may be the interaction of these androgen in the brain rather than the ovaries that lead to the development of PCOS. PCOS affects 5-10% of women aged 18 to 44 and this study, using mice, has provided valuable insight into the onset of this syndrome.

  • A new study finds in mice that whole body vibration (WBV), a less intensive form of regular exercise, mimics the benefits derived from regular exercise. To investigate the benefits of WBV, scientists exposed normal mice and mice which don’t produce a receptor for leptin (a hormone associated with the feeling of being full after eating) to no exercise, either daily treadmill exercise, or WBV for three months. They found that in the normal mice and the leptin-deficient mice, WBV and exercise, affected mice in a similar way — reduced body weight, enhanced muscle mass, and insulin sensitivity compared to mice that were sedentary (no exercise group). This research, using mice, suggests that WBV may be useful as a supplemental therapy for individuals suffering from metabolic disorders or morbid obesity and where regular exercise is not an option.
  • Researchers have created a backpack-sized artificial lung that was able to fully oxygenate the blood of sheep for six hours. William Federspiel, at the University of Pittsburgh, has subsequently said the device has been used successfully on sheep for five days. The device had to combine a pump and gas exchange while remaining small enough to be carried. Even smaller devices have been developed to work on rats, using ultrathin tubing, just 20 micrometers in diameter. Such technologies could allow people with lung failure to continue with many of their daily activities, rather than becoming bed-ridden and attached to today’s artificial lung machines.

Image Credit: William Federspiel

  • A study funded by the NC3Rs explores how different handling methods affected behavior in cognitive tasks. Tail handling is still one of the more common methods of handling mice in the laboratory despite variable evidence that alternative methods such as cupped or tunnel handling may be less stressful for the animal. The researchers compared how mice reacted to new stimuli after being transferred into the testing area via a tunnel or being picked up by the tail. Because being picked up by the tail may be stressful for mice, tests which involve exploration may be affected by tail handling – as one consequence of stress in mice is freezing behavior (staying immobile). They found that the tunnel handling facilitated greater exploratory behavior, indicating that the simple process of tail handling may confound behavioral measures relating to anxiety. 3Rs research like this can help to understand the needs of animals in research labs, with the aim of improving animal welfare and the replicability of experimental results.

Image Credit: Jane Hurst, University of Liverpool.

Speaking of Research

SYR: How sheep can help us understand why girls are reaching puberty at younger ages

michelle-bedenbaughThis guest post is the second written by Michelle Bedenbaugh, a Ph.D. student in the Physiology and Pharmacology Department at West Virginia University. Check out her first post on the benefits of using large animal models to study reproduction. It is also part of our Speaking of Your Research series of posts where scientists discuss their own research. In this post, Michelle discusses some of the cells and signaling pathways that are important for controlling the timing of puberty and how the use of sheep as a model is beneficial for this type of research. If you would be willing to write a guest article for Speaking of Research, please contact us here.

For those of you who have been watching the news in the United States over the past 5-10 years, you have probably heard a few discussions about the fact that girls are reaching puberty at younger ages.  In the 1980s, girls normally reached puberty around the age of 13.  In 2010, the average age of girls reaching puberty had dropped to 11 and has since continued to decline.  Reaching puberty at earlier ages is associated with several adverse health outcomes, including polycystic ovary syndrome (PCOS), metabolic syndrome, obesity, osteoporosis, several reproductive cancers and psychosocial distress.  The public and researchers have pointed fingers at several potential culprits, including an unhealthy diet, chemicals that disrupt the body’s normal hormonal environment, and an individual’s genetic predisposition to disease.  In reality, a combination of factors have probably led to the decrease in the age at which girls reach puberty, but I don’t want get into a discussion about these factors today.  Instead, I want to talk about some of the signaling molecules in the body that these factors may be influencing to affect the initiation of puberty.

As with many processes in the human body, the brain plays a critical role in the control of reproduction and the timing of puberty.  Within a specific area of the brain called the hypothalamus, several populations of neurons (specialized cells in the brain) exist that control reproduction.  The activity of these neurons is influenced by various factors that are communicated from other parts of the body and outside environment to the brain, including nutritional status, concentrations of sex steroids (like estrogen and testosterone), genetics, and many other external factors.  All of these factors tell the brain when an individual has obtained the qualities necessary to successfully reproduce and therefore undergo pubertal maturation.  Gonadotropin-releasing hormone (GnRH) neurons found in the hypothalamus are the final step in this chain of communication and are essential for the initiation of puberty.

A GnRH neuron present in the hypothalamus.

A GnRH neuron present in the hypothalamus.

Most of these nutritional, hormonal, genetic and environmental signals are not directly communicated to GnRH neurons.  Instead, they are conveyed through other types of neurons that then relay this information to GnRH neurons which either stimulates or inhibits the release of GnRH.  Because GnRH is a signaling molecule that ultimately stimulates the maturation of male (sperm) and female (egg) gametes, stimulating GnRH in turn stimulates reproductive processes while inhibiting GnRH inhibits reproductive processes.  The perfect balance of stimulatory and inhibitory inputs is needed for GnRH to be released and for puberty to be initiated.  Consequently, if stimulatory inputs signal to increase GnRH prematurely, puberty will occur earlier, which may result in several of the health concerns that were mentioned above later in life, including reproductive cancers and psychosocial distress.  In contrast, if inhibitory inputs block the release of GnRH, puberty will never occur and result in infertility.

My research looks at some of these stimulatory and inhibitory inputs and how they communicate with each other, as well as with GnRH neurons.  Two of the stimulatory signaling molecules that we research are kisspeptin and neurokinin B (funny names, I know).  We also study dynorphin (another funny name), a molecule that inhibits GnRH release.  These three molecules can all individually affect GnRH release and therefore reproduction.  However, the really cool thing about these three molecules are that they are actually present together in a special type of neuron that is only found in one small and highly specific area of the hypothalamus.  Because these neurons contain kisspeptin, neurokinin B, and dynorphin, they are often called KNDy (pronounced “candy”) neurons.  The fact that kisspeptin, neurokinin B, and dynorphin are all present in these KNDy neurons together allows for them to communicate directly and affect each other’s release.  This communication then ultimately affects the release of GnRH.  Before puberty, inhibitory inputs, like dynorphin, dominate and don’t allow for adequate amounts of GnRH to be released to stimulate reproduction.  As an individual matures, stimulatory inputs, like kisspeptin and neurokinin B, begin to outweigh inhibitory inputs, and GnRH can be released in adequate amounts to support reproductive processes.  Below is a figure that summarizes how we think all of this works within the body.  However, there is still a lot that we don’t know about how kisspeptin, neurokinin B and dynorphin interact with each other that is waiting to be discovered!

Hypothesized model for the initiation of puberty. (1) Internal and external factors are communicated to the body. (2) Next, these factors are relayed through various signaling pathways to stimulatory and inhibitory molecules present in neurons located in the hypothalamus. (3) Stimulatory and inhibitory molecules travel to GnRH neurons and affect the release of GnRH. (4) GnRH stimulates reproductive processes that are critical for the initiation of puberty. (5) Once all of the proper conditions are met, reproductive maturity is attained.

Hypothesized model for the initiation of puberty. (1) Internal and external factors are communicated to the body. (2) Next, these factors are relayed through various signaling pathways to stimulatory and inhibitory molecules present in neurons located in the hypothalamus. (3) Stimulatory and inhibitory molecules travel to GnRH neurons and affect the release of GnRH. (4) GnRH stimulates reproductive processes that are critical for the initiation of puberty. (5) Once all of the proper conditions are met, reproductive maturity is attained.

To complete all of these studies, we use sheep as our model.  I know what some of you are thinking.  “How in the world would sheep serve as a good model for how puberty is initiated in humans?  I don’t think I am similar to a sheep at all!”  In fact, sheep are actually an excellent model in which to do this research.  The signaling pathways that affect the release of GnRH in sheep are very similar to the signaling pathways in humans, and in some cases, are even more similar to the human pathways than the pathways present in mice or rats.  In humans and sheep, neurokinin B has only been found to stimulate GnRH release.  However, in rodents, there have been reports of neurokinin B both stimulating and inhibiting GnRH release.  Since neurokinin B is one of the main signaling molecules that we study, using sheep instead of mice or rats is more beneficial for modeling what is occurring in humans.


Because we have to collect several blood samples from the sheep in order to measure hormone concentrations, having an animal with a larger blood volume is also advantageous.  Several hormones in the body (including GnRH) are released in a pulsatile manner, meaning one minute GnRH concentrations are high and a few minutes later they are low.  Therefore, in order to appropriately measure GnRH, blood samples need to be taken every 10-12 minutes for several hours.  This is not feasible in rodents.  If you took blood samples as frequently in rodents as is possible in sheep, you would risk killing the animal.  Some scientists who use rodents as their research model attempt to get around this issue by taking blood samples less frequently.  However, this means their hormone measurements are less accurate.

These are just a few of the many reasons why we conduct our research in sheep (to learn more about the advantages of using sheep and other large animal models to conduct research involving reproduction, see my previous post).

While most people (including myself) do not look back fondly on our awkward pubertal years, I absolutely love studying the signaling pathways the body uses to determine when it is ready to successfully reproduce.  We have discovered quite a bit over the past few decades concerning how different internal and external factors affect pubertal maturation, but there are still so many unknowns left to be determined.  I look forward to hopefully discovering some of these unknowns and improving our understanding of how puberty is initiated in both humans and livestock species.

Michelle Bedenbaugh

SYR: The case for using large animal models to study reproduction

michelle-bedenbaughThis guest post is written by Michelle Bedenbaugh, a Ph.D. student in the Physiology and Pharmacology Department at West Virginia University. It is part of our Speaking of Your Research series of posts where scientists discuss their own research. Michelle’s research involves examining the brain’s role in the initiation of puberty.  In this post, Michelle discusses the benefits of using large animal models to study reproduction.  If you would be willing to write a guest article for Speaking of Research, please contact us here.

With the increasing pressure to publish papers and the decreasing amount of funds made available to conduct experiments, it has become more difficult for researchers to survive and thrive in an academic setting (see here, here, and here). Scientists have had to adapt, and in many situations, this has led to a significant amount of research that relies heavily on small animal models, including rodents and invertebrates.  In addition to being less expensive than large animal models (sheep, pigs, cows, horses, etc.) there are also more genetic tools and techniques available to use in small animal models.  For example, transgenic mice, where certain genes can be either deleted or overexpressed, are used commonly by researchers worldwide.  Other cutting edge techniques, like optogenetics, where light can be used to control the activity of cells in the brain, are also being used on a more routine basis in rodent models and currently don’t exist in large animal models.

Optogenetics involved using light to control genetically modified cells inside the body

Optogenetics involved using light to turn off or on cells in the brain

While it is most likely easier, cheaper, and faster to conduct experiments using small animal models, in certain situations they are not always the most comparable to humans.  When modeling certain diseases or understanding certain physiological processes, larger animals, like sheep, pigs, and cows, provide a better model for scientists.  This post aims to look at some areas where larger mammals can provide important knowledge or understanding.

A few of the more obvious benefits to using large animal models when compared to small animal models are that large animals are more analogous to humans in regards to body size, organ size, and lifespan.  In addition to these similarities, animals like sheep, cows, and pigs are much less inbred when compared to rodents.  Some would argue that it is advantageous to use animals that are highly inbred because this decreases the amount of variability in an experiment.  However, each human has a unique genetic makeup, and sometimes solutions for problems in inbred rodents cannot be translated for use in humans.  Therefore, in these instances, it is probably more beneficial to use a less inbred large animal model.  Most large animal models also have the added benefit of being an economically important species.  The majority of researchers who use large animal models are attempting to find solutions to health issues that are present in humans.  However, successful experiments in large animal models have the ability to affect both human and animal health.  For example, if a researcher made an important discovery about the way food intake is controlled in cows, it would have the possibility of improving human health, as well as increasing profitability for cattle producers.  Because cows are very similar to sheep, it may also benefit sheep production as well.  Rodents are not an economically important species that provides food, fiber, or other essential products used by the human population.  Consequently, discoveries made in rodents and other small animal models may only benefit humans if the results are translatable.

My particular research focuses on furthering our understanding of how puberty is initiated in girls, and we use sheep as our animal model.  I won’t get into the specific benefits of using sheep to conduct puberty research today because I will discuss this more in my next post.  However, I did want to touch briefly on some of the advantages of using large animals to perform research used to study reproduction in a broader sense.

The brain plays an essential role in controlling reproductive processes.  The brain structure of large animals is more closely related to humans than small animals because large species have a sulcated cortex (meaning the surface of the brain is wrinkly) as opposed to small animal species which have a smooth cortex.

Comparison between mouse (smooth cortex) and human (sulcated cortex) brain. [Credit: Elizabeth Atkinson, Washington University in St. Louis]

Comparison between mouse (smooth cortex) and human (sulcated cortex) brain. [Credit: Elizabeth Atkinson, Washington University in St. Louis]

Sheep also have the advantage of their brain and the cellular pathways present within it being similarly organized to what is observed in non-human primates.  Hormones serve a major role in relaying information from the brain to reproductive organs and vice versa.  The actions of several hormones that aid in controlling reproduction in female sheep (like estrogen and progesterone) parallel the actions of these hormones in humans.  Older sheep also have a similar response to estrogen replacement therapy when compared to post-menopausal women.  The development and function of several structures on the ovary of sheep is also similar to that which is observed in women.  These structures have a major influence on the reproductive cycle and are critical for the maturation of female gametes (sometimes referred to as eggs).  Assisted reproductive technologies, many of which are used for in vitro fertilization (IVF) protocols in women who are having trouble conceiving, have been adapted from procedures used in livestock species.  For example, artificial insemination, where semen is collected from a male and usually frozen so that it can be used to inseminate a female at a later time, is commonly used in cows, sheep, horses and pigs and is similar to procedures conducted in humans.

Credit: Livestock Breeding Services - http://www.livestockbreedingservices.com.au/images/servicesai.jpg

A laparoscopic procedure is used to artificially inseminate sheep


Embryo transfer, where embryos from one female are placed into the uterus of another female, are also used in livestock species and humans.  In addition, sheep are also an excellent animal model for studying pregnancy.  Sheep are used often to examine how stress, maternal nutrition, and exposure to excess hormones or toxins affect the development of a fetus.

These are just a few examples that display reproductive processes occurring in many large animal species are easily relatable to those same processes which also occur in humans.  I only touched on a few species today, but there are many more animal models that are underused in research and would serve as great models for humans.  In addition, I only discussed some of the ways these animals can be used to study reproduction when in fact they can be used to mimic many other biological processes that occur in humans.  Depending on the subject matter being researched, the use of some animal models is more appropriate than others.  Regardless of cost or time, researchers should always consider which animal model may be the most appropriate for their experiments.  I believe conducting research in a variety of species as opposed to just one or two species will always be more advantageous and will aid us in solving health issues in humans more quickly.

Michelle Bedenbaugh

Research using sheep leads to a new device to record and stimulate the brain

A group of Australian and American researchers have used sheep to develop and test a new device (original paper) – the stentrode – for recording electrical signals from inside the brain. The research was published in Nature Biotechnology. This new technology removes one of the main obstacles to developing efficient brain-computer interfaces: the need for invasive surgery.

The “stentrode” is a group of small (750 µm) recording electrodes attached to an intracranial endovascular stent, which allows implantation of the electrodes inside the brain without invasive surgery. This allows high quality recording or stimulation of specific areas of the brain, without many of the risks associated with invasive brain surgery.

Image courtesy of the University of Melbourne

Image courtesy of the University of Melbourne

A stent is a tube-shaped device whose walls are made from a metallic mesh, designed to navigate inside brain’s system of blood vessels, until a desired position is reached. Once in place the mesh is expanded, securing it against the blood vessel walls. Importantly, stents are designed to be implanted by inserting them through a large blood vessel, like the jugular vein, and gradually “pushing” them into the desired position, by twisting and turning at critical juncture points where veins branch. During this implantation procedure the surgeons observe the stent’s location using a non-invasive imaging technique named cerebral angiography.

Recording the electrical activity of brain cells with high fidelity is the basis of new technologies to restore quality of life to many people with neurological diseases. For example, through brain-computer interfaces that interpret neural signals, people paralysed by damage of the spinal cord have been made able to control external devices, such as wheelchairs, robotic arms, and exoskeletons. Much of this work was initially done in monkeys– getting them to also control wheelchairs and robotic arms. Moreover, brain recording devices can be used to detect the timing and location of seizures with great precision, which helps minimise damage to healthy parts of the brain when treatment involving surgery is necessary.

One obvious problem with the current technologies is that there is a clear trade-off between the quality of recordings obtained, and degree of invasiveness. To explain this, let’s look at two extremes of techniques for recording brain activity – electroencephalogram (EEG) and microelectrode arrays.

EEG, recording from the scalp, is by far the least invasive technology: electrical activity of the brain can be recorded through a cap dotted with electrodes, and no surgery is required. However, because the signals being measured are so weak (due to the distance between brain cells and the recording electrodes), this technique can only detect the combined activity of millions of brain cells, when they work at the same moment (signals from small groups of cells tend to average out, not producing an electrical “spike” large enough to be detected far away). Thus, devices controlled by brain-computer interfaces based on EEG tend to be difficult to control, and have few “degrees of freedom” (how many different actions can be specified by the user). Moreover, it is difficult to determine exactly where the signals of interest are coming from, and electrical activity from regions well inside the brain is much harder to detect.

EGG. Image courtesy of Saint Luke’s Health System

EGG. Image courtesy of Saint Luke’s Health System

At the other end of the continuum are recordings using microelectrode arrays- small devices that are implanted directly in the brain, which contain many small metallic probes each capable of “listening” to the electrical activity of a single neurone, or a small groups of neurones. This technique, developed over many years of studies in rats, cats and monkeys, has been used recently to demonstrate the ability of a tetraplegic patient to control its own muscles again, using a brain-computer interface which included a microelectrode array to record the signals that encoded the participant’s intention to move, coupled to stimulation devices attached to different arm muscles.  Much more refined control can be achieved with this method, as one can potentially record individual signals from thousands of neurones, across many brain areas. The disadvantage, however, is clear: these devices have to be implanted directly in the brain, requiring complex neurosurgical procedures. Moreover, the insertion of the electrode arrays in the brain causes local damage, which triggers inflammatory tissue responses that, over time, can reduce the quality of recordings. Although this damage can be minimised by using larger electrodes that lie on the surface of the brain, instead of penetrating it (electrocorticography, ECoG), the need for invasive surgery remains.

Microelectrode array. CC Image by Richard A Normann. Tbe actual size of this array is 4 x 4 mm

Microelectrode array. CC Image by Richard A Normann. Tbe actual size of this array is 4 x 4 mm

As we can see, the stentrode has the potential to be the best of both worlds – offering the accuracy of microelectrode arrays and the benefits of avoiding non-invasive surgery usually associated with technologies like EEG.

Part of the problem solved by the stentrode developers was to find an adequate animal model, which would yield information valid to the situation of the human brain. Sheep were chosen due to the similar topology of the brain’s venous system, and the similar diameter of the critical blood vessels. The stentrodes were implanted inside a large vein that lines the somatosensory cortex – the part of the brain that encodes sensory information about touch, as well as muscle contraction and position of the body’s joints. Importantly, once implanted, they stayed in place without damaging the brain or blood vessels, and allowed stable neural recordings for over 6 months – while the sheep were freely moving around.

Stock image of sheep in research (in the UK) by Understanding Animal Research.

Stock image of sheep in research (in the UK) by Understanding Animal Research.

Currently envisaged applications of this new technique include “reading” signals for control of artificial limbs and seizure prediction in epilepsy. With some modifications, the same technique can be used for localised electrical stimulation of the brain, which may allow new treatments for Parkinson’s disease, and obsessive-compulsive disorder. Deep Brain Stimulation, a currently used treatment to treat the tremors associated with Parkinson’s, requires invasive brain surgery to implant electrodes – this process could be made easier and safer using stentrodes. Besides being good news for people who may one day benefit from an easier way to have electrodes inserted in the brain for treatment of diseases, this story also illustrates two important points. First is the usefulness of animal models to develop treatments that directly benefit people. The sheep brain is not identical to the human brain, but can be judiciously used to model a critical feature of the latter, in a manner that is directly relevant for testing a device intended for human use. Second, that results take time to translate from basic research in animals to human use. The current generation of brain-computer interfaces would never have been developed were it not for decades of research on seemingly “basic” topics, such as how to best record different types of electrical signals from the brain, how and where the brains of various animals encode information for sensation and movement, and how blood vessels are organised and function. This is however just the beginning, and a lot more needs to be done on the way to useful and safe devices.

Marcello Rosa and Tom Holder

Original Paper: Oxley, Thomas J., 2016, Minimally invasive endovascular stent-electrode array for high-fidelity, chronic recording of cortical neural activity, Nature Biotechnology34, 320-327. Doi:10.1038/nbt.3428

Clinical trial success for Cystic Fibrosis gene therapy: built on animal research

This morning the Cystic Fibrosis Gene Therapy Consortium (GTC) announced the results of clinical trial in 140 patients with cystic fibrosis, which demonstrate the potential for gene therapy to slow – and potentially halt – the decline of lung function in people with the disorder. It is a success that is built on 25 years of research, in which studies in animals have played a crucial role.

Cystic fibrosis is one of the most commonly inherited diseases, affecting about one in every four thousand children born in the USA, and is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The CFTR gene produces a channel that allows the transport of chloride ions across membranes in the body, and the many mutations identified in cystic fibrosis sufferers either reduce the activity of the channel or eliminate it entirely. This defect in chloride ion transport leads to defects in several major organs including the lungs, digestive system, pancreas, and liver. While the severity of the disease and the number of organs affected varies considerably, cystic fibrosis patients often ultimately require lung transplant s, and too many still die early in their 20’s and 30’s as the disease progresses.

In a paper published in Lancet Respiratory Medicine today (1), the GTG members led by Professor Eric Alton of Imperial College London compared monthly delivery to the airway of a non-viral plasmid vector containing the CFTR gene in the liposome complex pGM160/GL67A using a nebuliser with a placebo group who received saline solution via the nebuliser. They reported stabilisation of lung function in the pGM169/GL67A group compared with a decline in the placebo group after a year. This is the first time that gene therapy has been shown to safely stabilise the disease, and while the difference between the treated and control group was modest, and the therapy is not yet ready to go into clinical use, it provides a sound bases for further development and improvement.


The Chief Executive of the Cystic Fibrosis Trust, which is one of the main funders of the GTC, has welcomed the results, saying:

Further clinical studies are needed before we can say that gene therapy is a viable clinical treatment. But this is an encouraging development which demonstrates proof of concept.

“We continue to support the GTC’s ground-breaking work as well as research in other areas of transformational activity as part of our mission to fight for a life unlimited by cystic fibrosis.”

So how did animal research pave the way for this trial?

Following the identification of the CFTR gene in 1989 scientists sought to create animal models of cystic fibrosis with which to study the disease, and since the early 1990’s more than a dozen mouse models of cystic fibrosis have been created. In some of these the CFTR gene has been “knocked out”, in other words completely removed, but in others the mutations found in human cystic fibrosis that result in a defective channel have been introduced. These mouse models show many of the defects seen in human cystic fibrosis patients and over the past few years have yielded important new information about cystic fibrosis, and in 1993 Professor Alton and colleagues demonstrated that it is possible to deliver a working copy of the CFTR gene using liposomes to the lungs of CFTR knockout mice and correct some of the deficiencies observed.

To get a working copy of the CFTR gene to the lungs of cystic fibrosis patients Professor Alton and colleagues needed three things:

• A DNA vector containing the working CFTR gene that is safe and  can express sufficient amounts of the CFTR channel protein in the lungs to correct the disease

• A lipid-like carrier that can form a fatty sphere around the DNA vector to so that it can cross the lipid membrane of cells in the lung, as “naked” DNA will not do this efficiently.

• A nebuliser device that produces an aerosol of the gene transfer agent so that it can be inhaled into the lungs of the patient.

Several early attempts to use gene therapy using viral vectors to deliver the working copy of the CFTR gene to patients failed because the immune response rapidly neutralised the adenoviral vector (see this post for more information on challenges using adenoviral vectors), and while attempts to use non-viral vectors were more promising, it was found that they caused a mild inflammation in most patients, which would make then unsuitable for long term use. As reported in a paper published in 2008 the GTC members developed and assessed in mice a series of non-viral DNA vectors, repeatedly modifying them and testing their ability to both drive CFTR gene expression in the lungs and avoid inducing inflammation. They finally hit on a vector – named pGM169 – which fulfilled both key criteria.

Earlier the consortium had undertaken a study to determine which carrier molecule to use in their non-viral gene transfer agent (GTA). To do this they assessed 3 GTA’s, each consisting of a lipid like molecule that could form a sphere around the non-viral DNA vector; either the 25 kDa-branched polyethyleneimine (PEI), the cationic liposome GL67A, or as a compacted DNA nanoparticle formulated with polyethylene glycol-substituted lysine 30-mer. Because there are significant differences in airway physiology between mouse and human they carried out this study in sheep, whose lung physiology more closely matches that of humans. The study identified the cationic liposome GL67A as the most promising candidate, resulting in robust expression of the CFTR transgene in the sheep lungs.

Studies in sheep play a key role in the development of gene therapy for cystic fibrosis

Studies in sheep play a key role in the development of gene therapy for cystic fibrosis

It now remained to bring the DNA vector and carrier together. In a 2013 publication the consortium reported that repeated aerosol doses of pGM169/GL67A to sheep over a 32 week period were safe and induced expression of the CFTR transgene in the sheep lungs, although the level of expression varied between individuals (this variation was also observed in human CF patients in the clinical trial reported today). A final study, this time in mice, assessed the suitability of the Trudell AeroEclipse II nebuliser as a device to create stable pGM169/GL67A aerosols, finding that it did so in a reproducible fashion. When aerosolized to the mouse lung, the new pGM169/GL67A formulation was capable of directing persistent CFTR transgene expression for at least 2 months, with minimal inflammation. These studies provided the evidence to support the gene delivery system and dosage strategy used in the clinical trial reported today.

The trial results announced today are an important accomplishment, but they mark a beginning rather than the end for Cystic Fibrosis gene therapy. It will be necessary to improve the efficiency of the therapy before it can enter widespread clinical use. Animal research will certainly play an important part in this work, notably the observation that the efficiency of CFTR gene delivery using this strategy was varied between individuals in both sheep and humans indicates that sheep are a good model in which to assess changes to improve the consistency and effectiveness of the gene therapy.

If you would like to know more about this cystic fibrosis gene therapy clinical trial you can watch two videos recorded at a meeting for cystic fibrosis patients at ICL on the  Cystic Fibrosis Trust website.

Paul Browne

1) Alton E.W.F.W. et al. “Repeated nebulisation of non-viral CFTR gene therapy in patients with cystic fibrosis: a randomised, double-blind, placebo-controlled, phase 2b trial” Lancet Respiratory Medicine Published online July 3, 2015

The BUAV – Unsubstantiated Claims, Spies and Videotapes

This article was originally posted on 11 June 2014. On 4 June 2015 we received representation from CFI asking us to reconsider some of the wording. Having considered all of their comments and reflected upon the article, we have amended these and reposted them as they appear below.

For the second time this year the British Union for the Abolition of Vivisection (BUAV; now called Cruelty Free International) infiltrated an animal research facility and sent footage to a British tabloid. For a second time this year, the BUAV has shown us nothing the public could not find out for themselves. No unnecessary suffering. No misbegotten science.

Let us also make a quick distinction between whistleblowing and infiltration. Whistleblowing is a standard lab policy in all UK labs whereby anyone who sees anything they find concerning (particularly relating to animal welfare) can – and should – report it to one of a number of different people up the chain of leadership. Infiltration is a tactic of sending someone into a lab with the express intention of filming as much as they can to create the most dramatic short video possible. Those involved are often double paid by both the organisation they infiltrate and the animal rights group who sent them there. Importantly, infiltrators are actively trying to find shocking video moments. Furthermore, whereas whistleblowers should report animal welfare issues quickly, infiltrators will tend to sit on any animal welfare issues they see until they have finished working at an institution – leading to unnecessary animal suffering.

Cambridge University research into Huntington’s and Batten disease
Last weekend, the Mirror on Sunday ran a story alleging sheep were “being left to suffer in pain and misery for pointless experiments” at Cambridge University following a BUAV infiltration. It should be noted that we have given examples before of the Daily Mirror playing fast and loose with the truth of animal research. Thankfully the Mirror on Sunday provided more balance than its Daily sister-publication usually does by including the perspective of both a patient and a scientist.

The BUAV took hours and hours of footage provided by their undercover infiltrator and edited it down to 4 mins 21 of what we must assume they considered the “worst” footage. In it we see several sheep exhibiting the symptoms of Batten’s disease. The BUAV also make several allegations about animal welfare, none of which seem to be corroborated by the video footage released so far.


We see sheep, group housed in large hay-covered pens, clearly well cared for, and behaving calmly when examined by scientists and veterinarians. It is a mark of the BUAV’s approach that they make a great play on the term “crush cage”, when in fact these cages (known as squeeze chutes in the US) are widely used by farmers to hold an animal still to minimise the risk of injury to both the animal and the operator while work – veterinary care or routine husbandry – on the animal is performed. It is worth considering that the UK eats around 1 million sheep and lambs per month.

While this may be disturbing, the reality of Batten’s disease in humans, and its effects on a patient’s loved ones, are far, far crueller.

The University of Cambridge has strongly defended this research, pointing out that:

The researchers have been testing a sheep model of Huntington’s Disease developed by collaborators in New Zealand and Australia and studying a line of sheep that carries a natural mutation for Batten’s Disease.

Whilst every attempt is made to keep distress to a minimum, the very nature of these diseases means that the animals will show symptoms related to damage of the nervous system similar to those seen in humans.

A treatment that could slow the disease process once it has started would be a major advance, but the ideal treatment would prevent the onset of symptoms.

MSD testing and developing vaccines for pets
In March, the Sunday Express (another tabloid not known for its science journalism…to put it mildly) ran a story purporting to show “horrific photographs and video footage showing puppies panicking as they were injected with needles before being dissected” that had been taken by “a brave undercover investigator who worked at the centre for eight months” while “also working with the BUAV throughout that time”. The research at MSD Animal Health was for testing and developing veterinary vaccines. This time the BUAV edited eight months recording into six minutes of footage that showed …. nothing. No, not nothing, it showed researchers and lab technicians conducting research with animal welfare heavy on the list of priorities. The animals were healthy, well socialised, group housed and cared for by researchers who stroked and chatted to the animals.

The video did include the dissection of a dead animal. This doesn’t look nice. Dissection rarely does. However, let us remember that the animal had been humanely killed and its welfare was not influenced by the science being carried out after it died.

Who are the BUAV?
The activities of animal rights groups cost money – the BUAV spent well in excess of £1.3 million in 2013 (and almost £2 million in 2012). With fierce competition between the numerous large national animal rights groups in the UK addressing the animal research issue (including BUAV, Animal Aid, NAVS, PETA UK and HSI), the public donations tend to go to the one with the biggest campaigns and resulting media stories (see our post on structure and motivations of animal rights groups).

The BUAV spend around 10% of their £1.7m (2013; $2.9m) – £2.0m (2011/12; $3.4m) income on investigations. Half of this is on staffing, and half is on “Other Costs”. Given the sums involved it is not unreasonable to assume that the BUAV has lab technicians it has placed in labs on its payroll (note the Sunday Express described the infiltrator at MSD as “working ” with the BUAV). These are not casual whistleblowers, but people who are working at animal research facilities with the express intention of creating newsworthy videotapes.

BUAV infiltration Finances

From BUAV accounts 2011-13

One has to wonder how many BUAV infiltrators are in labs around the UK. Moreover, one wonders, how many BUAV infiltration videos were never publicised due to the lack of newsworthy footage (even after clever editing)? Each of the above infiltrations involved hundreds of hours of footage being taken of which 5 minutes was considered dramatic enough for watching. Even those five minutes lack any real substance.

To the BUAV – Prove it!
To the BUAV we ask you for the openness and transparency you accuse the research community of lacking. Show us the rest of the footage. Show us the hours and hours of footage that never made it onto your final mix tapes.
Will we find hours of shocking footage? Or will we find hours and hours of individuals working hard, caring for animals, and conducting research in a manner which provided high standards of animal welfare. It’s for you to prove.

Speaking of Research

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Trial of gene therapy in heart failure launches following success in rats and pigs.

Heart failure is a deadly condition that affects about two out of every hundred adults in the USA, and occurs when the heart is unable to provide sufficient pump action to maintain blood flow to meet the needs of the body. Among the more common causes are heart attacks and hypertension, but less frequently it can also be caused by viral infections or autoimmune diseases.

While the therapies available for heart failure have improved a lot in recent years thanks to the development of drugs such as Ivabradine, heart failure is still a major cause of death and disability, particularly among the over 65’s. As you might expect scientists around the world are developing several innovative approaches to treating heart failure – the British Heart Foundation’s “Mending Broken Hearts” appeal is an excellent example of the concerted effort now underway – and we have highlighted on this blog and our Facebook page  techniques ranging from electrical stimulation of the vagus nerve to collagen patches that stimulate tissue repair.

To those animal research has added another: Gene Therapy!

Image courtesy of Imperial College London

Image courtesy of Imperial College London

Yesterday the BBC reported the recent launch in the UK of a Clinical trial of gene therapy for heart failure, and Professor Peter Weissberg of the British Heart Foundation, who funded much of the basic and applied research leading up to this trial, noted the promise that this approach holds:

Whilst drugs can offer some relief, there is currently no way of restoring function to the heart for those suffering with heart failure. This early clinical study is the culmination of years of BHF funded laboratory research and offers real promise.

“Gene therapy is one of the new frontiers in heart science and is a great example of the cutting edge technologies that the BHF is using to fight heart failure. Gene therapy aims to improve the function of weak heart muscle cells, whereas our Mending Broken Hearts Appeal is aimed at finding ways to replace dead heart muscle cells after a heart attack. Both approaches are novel and both offer great potential for the future.””

This trial, which is being run by researchers at Imperial College London and the Royal Brompton Hospital, is part of a multinational multicentre trial of 200 patients – CUPID-2b – which seeks to assess whether injection into heart tissue of a adeno-associated virus 1-based gene therapy vector driving expression of the enzyme SERCA2a can repair damaged heart tissue and improve cardiac function. The reasoning behind this is that as a calcium transport protein SERCA2a plays a key role in maintaining the correct balance of calcium ions in heart muscle cells, and studies in both human heart failure patients and animal models of heart failure the amount of SERCA2a is lower than normal. A combination of studies in human heart muscle tissue and animal models of heart failure over several years demonstrated that this decrease is associated with calcium overload, an abnormal heart rhythm and tissue damage, suggesting that increasing the amount of SERCA2a in the injured heart tissue may reverse the damage.

In 2010 paper was published reporting on the first clinical trial of this therapy1 (available to read for free), whose primary goal was to assess the safety of the technique, and it noted that studies in animal models of heart failure provided vital evidence underpinning the decision to move it into clinical trials.

In preclinical HF models in rodents,(20) pigs,(18) and sheep,(21) increasing the level of SERCA2a using recombinant AAV vectors was well tolerated and restoration of SERCA2a levels resulted in significant improvement in cardiac function and energetics, even when the underlying pathophysiology or insult (eg, mitral valve rupture or pacing induced heart failure) was not corrected. Based on these findings, this first-in-human Phase 1/2 Calcium Upregulation by Percutaneous Administration of Gene Therapy in Cardiac Disease (CUPID) trial(4) aims to restore levels of this key enzyme in HF patients via gene transfer of the SERCA2a cDNA by delivering a recombinant AAV (AAV1/SERCA2a) via percutaneous intra-coronary infusion.”

These studies, first in short- term studies in rats published in 2007 and subsequently longer duration studies in pigs and sheep published in 2008, indicated that this therapy was safe, could restore SERCA2a to normal levels, promoted heart muscle repair and improved heart function.

It’s just one more example of how animal research is contribution to the exciting field of gene therapy, and to advances in treating heart failure.

Paul Browne

1)      Jaski BE, Jessup ML, Mancini DM, Cappola TP, Pauly DF, Greenberg B, Borow K, Dittrich H, Zsebo KM, Hajjar RJ; Calcium Up-Regulation by Percutaneous Administration of Gene Therapy In Cardiac Disease (CUPID) Trial Investigators. “Calcium upregulation by percutaneous administration of gene therapy in cardiac disease (CUPID Trial), a first-in-human phase 1/2 clinical trial.” J Card Fail. 2009 Apr;15(3):171-81. doi: 10.1016/j.cardfail.2009.01.013. PMCID: PMC2752875