Tag Archives: sea urchin

Research Roundup: Red blood cell production in the lungs, sea urchin spines to fix bones, and trying to reverse aging in mice

Welcome to our fourth weekly roundup (now called “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.

  • new study finds that most of our blood cells are made in the lungs, not bone marrow. Using genetically modified mice that expressed a green fluorescent protein (GFP) and photon microscopy, scientists were able to track blood platelets as they circulated around the body in real time. Surprisingly, they found a large population of megakaryocytes, responsible for the production of blood cells, in the lungs. This population of megakaryocytes was found to produce upwards of 10 million platelets per hour — at least half of the body’s total platelet production. Further experiments, found another population of megakaryocytes just outside the lung tissue — about 1 million per lung. Additionally, using mice with no stem cells in the bone marrow (eliminating blood cell production there), they found that cells from the lungs migrated to and facilitated blood cell production in the bone marrow. Because of technological advances in genetic engineering and microscopy, this study challenged a decades-old assumption, central to the field of biology and medicine. This study will of course need to be replicated and assessment performed of whether these findings generalize to humans.

  • Sea urchin spines can be used to fix bones, offering a much needed refinement to the second most performed transplant procedure, after blood. Current procedures involving transplants for bone defects lead to subsequent complications as, for example, when brittle synthetic compounds break, causing further inflammation. This study therefore investigated whether the rigid structure of sea urchin spines represent a superior alternative material to currently used products. Sea urchin spines were first soaked in sodium hypochlorite for 30 min, and then rinsed in deionized water at 200C for 2 days in order to remove organic material, converting the spine to magnesium-substituted tricalcium phosphate (β-TCMP) scaffolds, while maintaining the rigidity of the original open-cell structures. When testing the material on rabbits and beagles, they found that bone cells and nutrients could flow through the pores and promote bone formation. They also found that the scaffold degraded easily as it was replaced by the new growth.

Image Credit: Lei Cao et al

  • A new study found that a population of neurons in the striatum is implicated in the Pavlovian associative learning. Pavlovian conditioning is a cornerstone of Behavioral Psychology; although the implications for subsequent research investigating links to disorders such as addiction, compulsive behavior, and schizophrenia are probably understated. In the present study, researchers exposed mice to an odor — banana or lemon — followed by a reward of condensed milk. By repeatedly pairing the odor with the reward, mice learned that a certain odor predicted a particular reward. Similar to Pavlov’s earlier experiment, the anticipation of the reward upon presentation of odor also occurred — mice licked the air — analogous perhaps to how humans lick their lips in anticipation of, for example, ice-cream. To understand how the brain regulates this response, these researchers focused on the striatum as this area has previously been associated with reward and decision making. Using optogenetics and chemogenetics, the researchers “turned-off” a tiny group of cells that support the principal neurons in the striatum. Predictably, mice with these cells turned-off only licked the air in anticipation of milk only half as often compared to baseline levels. This difference was most pronounced in mice that were first learning the odour-reward pairing and less pronounced in mice that had learned the pairing — suggesting that these cells are involved in the encoding of the Pavlovian response. This research may have further implications for other disorders as dysfunction of this group of neurons is also implicated in Huntington’s disease, Parkinson’s disease, and Tourette’s syndrome.

  • Researchers target senescent cells, cells involved in aging, to reverse the signs of aging in mice. “This is the first time that somebody has shown that you can get rid of senescent cells without having any obvious side effects.” says cell and molecular biologist Francis Rodier of the University of Montreal in Canada. Dr. Rodier was not connected to the study.  The cells also share some properties with cancer cells.  Researchers hope to explore applications that could lead to treatments for cancer as well as age-related diseases.

The mice needed for the study are genetically predisposed to faster aging allowing researchers to evaluate their new molecule. Here we see old mice which are less active and have hair loss. Humane endpoints are especially important in these types of studies.to ensure animals do not experience unnecessary discomfort. Image Credit: Peter de Keizer

  • New drug found to alleviate symptoms associated with Type 2 diabetes (insulin resistance) in mice. Diabetes affects 29.1 million Americans (9.3% of the population) with 1.4 million new diagnoses annually. It is the 7th leading cause of death in the USA and 90% of all cases of diabetes are of the Type 2 Management of Type 2 diabetes usually involves diet management and exercise, although oral medications may be used to bring glucose levels under control. Therefore, treatments that permit an individual to gain control of their life or to limit the symptoms associated with this disease are wanting. In the present study, scientists investigated the role of low-molecular-weight protein tyrosine phosphatase (LMPTP), in vivo for the first time. Using genetically modified mice that lacked LMPTP in the whole body and specifically in the liver, they found that LMPTP is associated with the development of Type 2 diabetes — improved glucose tolerance and reduced fasting insulin levels. They next developed, in vitro, a molecule inhibitor which preferentially binds to the receptor for LMPTP — blocking its action in the body. Testing this molecule, in mice, they again similar results to the experiment where the gene for LMPTP was removed (knocked out) — improved glucose tolerance and decreased fasting insulin levels. This study provided the first evidence of the signaling role of LMPTP in regards to Type 2 diabetes — and with subsequent replication and further testing may signal new hope for the millions of individuals that suffer from Type 2 diabetes.
  • The University of Cambridge has produced a series of videos about how its researchers are using animals (and people) to treat OCD – a neuropsychiatric disorder that can have debilitating effects. The three part series tracks science journalist and OCD-sufferer, David Adam, as he goes into the research labs at Cambridge and speaks to experts working with rats, monkeys and people. The video shows animal experiments being conducted, explaining why they are necessary. This is a great example of openness by the University of Cambridge. See other examples of videos being produced by labs.

Jeremy Bailoo

Laying the foundations of medical research

For the past couple of weeks a debate has been raging on the Opposing Views website between Speaking of Research’s Dario Ringach and the anti-vivisectionist Ray Greek. It has been a debate shaped by Dr. Greek’s attempts to persuade readers to agree with his very narrow concept of what prediction means in biology and his frankly impoverished view on the role of basic research in advancing medical science, and to oblige those debating them to accept a playing field rigged to set them at a disadvantage.  Judging by Dario’s most recent opinion piece and an article written a couple of days ago on the role of basic research Dr. Greek failed in this attempt.

British biochemist Sir Tim Hunt, who won the Nobel Prize for medicine in 2001.

Among all the discussion was one comment that directed readers to an excellent example of the value of basic research and the how study of animal models made many key discoveries possible. Earlier this week the BBC aired a program in their Beautiful Minds series featuring Sir Tim Hunt, who was awarded the Nobel Prize in 2001 for his research on how the cell cycle – through which cells grow and divide – is controlled.  Sir Tim’s work focused on the role of a family of proteins known as cyclins and as the Beautiful Minds program explains the initial breakthrough came from studies of the fluctuations in the pattern of protein expression during the cell cycle in sea urchin eggs.  This discovery was followed swiftly by the demonstration that cyclins were also present in yeast, clams and frogs, allowing Sir Tim and his colleagues to predict that they would have a role in regulating the cell cycle in many species,  including humans, a prediction that was soon confirmed to be true (1).

This program is a reminder that while discussion of animal research tends to focus on animals such as mice, rats and monkeys a lot is being learned about the fundamentals of our physiology through research on more humble model organisms, a diverse collection that includes not just sea urchins and clams but also nematode worms and flies .  These animals, along with other model organisms such as yeast and bacteria, enable us to study how living things work at a very fundamental level, laying the theoretical foundations for future applied and translational research that yields innovative treatments for disease and injury. At the same time, researchers studying other aspects of physiology often require higher mammals. The study of complex brain functions, including vision, hearing, memory, attention and motor planning, as well as how these functions fail in diseases of the central nervous system, is a prime example of this.

If you haven’t watched the Beautiful Minds series yet I strongly urge you to do so, the programs provide a fascinating (if not always flattering) insight into how science works.  And don’t delay: they are only available to view on the BBC iPlayer for another 7 days!

Paul Browne

1)      Pines J.  and Hunter T. “Isolation of a human cyclin cDNA: evidence for cyclin mRNA and protein regulation in the cell cycle and for interaction with p34cdc2.” Cell Volume 58(5), Pages 833-846 (1989)  PubMed: 2570636