Research Roundup: Heart regeneration, understanding of organ rejection, the saliva of ticks and more

Welcome to this week’s Research Roundup. 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 Research Roundup? You can send it to us via our Facebook page or through the contact form on the website.

• An understanding of the genetics that allow sea anemone to regenerate their heart could one day help human patients. Sea anemones are quite unique when compared to typical vertebrates (e.g. humans) — for example, they have genes that can produce heart cells even though they themselves do not have a heart. The also have the capacity to to regenerate where, for example, if an anemone is cut into pieces, each piece will regenerate into a new anemone. When analyzing the relationship between this regeneration capability and the functioning  of the “heart genes” in sea anemones, scientists at the University of Florida discovered that the genes interact with one another differently than human “heart genes”. Heart genes in humans have what are called lockdown loops, which tell the heart genes to turn on and stay on for the entire lifetime of the animal. Sea anemones do not have these lockdown loops, which allows them to turn cells with heart genes into any other kind of cell for regeneration. By further investigating the evolution of lockdown loops for sea anemone to vertebrates, scientists may be able to better understand possibilities for regeneration in vertebrates, who do not currently regenerate tissue — many lizards can regenerate tails, which is another line of research in this field.  This study is a perfect example on how basic research in organisms completely different from humans may one day have large reaching effects on human health. This study was published in the journal Proceedings of the National Academy of Sciences.

• Earliest molecular events leading to organ rejection identified in mice. Organ rejection remains a problem for transplant recipients — approximately 50% of all transplanted organs are rejected within 10 to 12 years. While methods are available to reduce the risk of organ rejection — such as immunosuppressant drugs — understanding the early molecular steps via which the body identifies cells as “non-self” provides important insight to reduce such risk. Fadi Lakkis, M.D., a senior co-author and scientific director of University of Pittsburgh’s  Thomas E. Starzl Transplantation Institute (STI) says, “For the first time, we have an insight into the earliest steps that start the rejection response.” The team hopes that  manipulating these earliest steps will disrupt the rejection process eliminating or minimizing transplantation failures. The study was a collaborative effort between researchers at the University of Pittsburgh, the Hospital of Sick Kids, the University of Toronto and Kobe University.  Using mice, they identified that a molecule called SIRP-alpha leads to the innate immune system activation and response, and that this molecule differs between non related individuals. In particular, when foreign tissue is transplanted, the SIRP-alpha of this new tissue binds to a receptor called CD47 in the host. This binding is what triggers the activation of the immune system leading to the rejection process. Both humans and mice express SIRP-alpha. Researchers say that sequencing this gene to identify potential donors and recipients may lead to lower organ rejection rates.  They also found that blocking the binding of SIRP-alpha and CD47 prevented the activation which may be used to find new ways to prevent organ rejection for patients that are not an exact match. This research was published in the journal Science Immunology.

• Insight into how humans developed their daytime vision comes from research on chick embryos.  Humans — along with other primates, various fish, reptiles, and birds — have a small spot in the center of their retina that allows them to have sharp vision in the daylight. Although, researchers have long acknowledged the existence of this spot, little has been known about the development of this sharp vision spot, known as the fovea, in humans. Researchers at Harvard Medical School recently investigated the development of this sharp vision spot in chickens, and found that growth factors involved in such development are regulated by enzymes that degrade retinoic acid, a derivative of Vitamin A, that plays important roles in embryonic development. Such pioneering work on the development of structures involved in having sharp vision (e.g. fovea) may help scientists to one day combat medical conditions involved with losing sharp vision (e.g. macular degeneration).

• A protein found in the saliva of ticks could help treat Myocarditis, according to researchers at the University of Oxford. Ticks are often able to feed on their hosts for over a week thanks to proteins in the saliva, called evasins, which prevent inflammation by binding to and neutralizing chemicals called chemokines. These chemokines also cause inflammation in myocarditis, heart attack and stroke. The scientists were able to grow tick saliva in yeast, using synthetic genes, thereby avoiding needing to individually milk ticks for their saliva. This study was published in Scientific Reports and was funded by the British Heart Foundation.

• Transcranial stimulation and/or physical therapy improves walking speed in Parkinson’s disease. Parkinson’s disease is a debilitating movement related disorder that affects approximately 10 million people worldwide. In America alone, this translates into a combined cost of approximately 25 billion dollars a year. Like many diseases with such a high prevalence, research is focused on two key aspects — understanding the etiology and the development of effective treatments of the disorder. Animal models, in mice, primates and other mammals, are integral in making progress in both aspects. For example, transcranial stimulation as a proof of  principle owes much to animal models – both in terms of its development and in relation to its evaluation of efficacy. Here, we see a good example of how basic research in animal models leads to improved quality of life due to a debilitating disease. In humans, these researchers found that noninvasive brain stimulation and physical therapy — alone or in combination — improve some measures of walking ability in patients with Parkinson’s disease. This study was published in the American Journal of Physical Medicine & Rehabilitation.