Did you know that spring began last week? Solar spring did, at least! Unlike astronomical spring, which begins in March, solar spring marks the point at which the daylight hours begin to increase again after shortening during the winter months.. Between now and May 4, we will gain four hours and four minutes of extra sunlight daily, which means the earth will be perking up and getting ready to put on its spring finery.
For many of us, this comes as a welcome change from the long nights we began to see in November. New light inspires hope and creativity. Science, too, is shedding new light on things we once understood dimly–and increasing clarity about things we once considered familiar and ordinary.
A new way of looking at irritable bowel syndrome (IBS) could change the way we diagnose and treat this disorder. A possible genetic link between overeating and obesity provides insight into a condition that complicates the lives of many. The creation of “cyborg” bacteria could revolutionize the treatment of diseases such as cancer–and could also help us tackle pollution. The discovery of a previously unknown type of ice makes it clear that we have a lot to learn about water. Find yourself a sun patch, get comfortable, and read along as we explore some of this hot new info!
It’s Not All In Your Head (Or Your Stomach): Gut-Brain Axis Connects IBS and Mood
Irritable Bowel Syndrome, or IBS, afflicts between 5-10% of the world’s population. With few clinical signs, it’s most often a diagnosis of elimination with few effective, long term treatments. Because patients with IBS so frequently suffer from depression or anxiety as well, it was once widely believed to be psychosomatic.
In recent years, physicians have begun to speculate that dealing with the disorder might cause depression and/or anxiety as opposed to the inverse.A study published in Molecular Psychology last week suggests that both of these conclusions could be false; furthermore, the study’s authors say that there are possible identifiable pathophysiological signs that might be useful in diagnosing IBS in the future.
The authors exhaustively combed through numerous studies on IBS and the psychiatric disorders frequently comorbid with it; this research included a recent genome-wide study of IBS patients, a genome-wide study of the human enteric nervous system, extensive patient histories, and prior research done on gut tissues of IBS patients.
They write that despite the lack of discrete diagnostic criteria, biological abnormalities have been identified on numerous levels of the gut-brain axis of IBS patients over the past thirty years. These abnormalities have been found in the smooth muscle cells, gut epithelium, and bile acids of IBS patients; abnormal neuroendocrine function and immune system activation have also been documented, along with grey matter abnormalities. Most recently, genetic mutations and dysbiosis of the gut have been identified.
The authors say that there is extensive evidence supporting an “integrative brain gut microbiome” model for understanding IBS as well as its psychiatric comorbidities.
The authors write that the gut and brain have a dynamic, bidirectional relationship that depends upon responsive communication between the central nervous system (CNS) and the enteric nervous system (ENS). Most of us have some familiarity with the CNS, which is made up mostly of the brain and spinal cord. We have another nervous system, though, composed of ganglia within the mucosa of our esophagus, stomach, and intestines–this is our enteric nervous system (ENS), and it’s the reason you feel the “butterflies” when you’re excited.
The researchers compared a GWAS of the human ENS to the GWAS of IBS patients (was that enough initials for you?). They point out that a gene called CADM2 is highly expressed in parts of the ENS responsible for communication between the system’s glia and neurons. Variations on this gene could lead to less effective communication between glial cells and neurons–a dysfunction that correlates strongly with stomach pain (a common symptom of IBS).
The researchers note that CADM2 is also implicated in neurodevelopmental disorders such as autism spectrum disorder, as well as nervousness. The correlation of these disorders with IBS is well-documented. Another gene that plays a role in the ENS, NCAM1, is involved in cognitive and psychiatric symptoms associated with IBS. They’re also expressed in the cells that regulate the movement of the stomach and intestines, which is often dysregulated and uncomfortable for IBS patients.
The IBS GWAS revealed several other genes associated with both IBS and psychiatric disorders, particularly depression and anxiety. Among them was SCN5A, which is associated with the serotonin pathway.
A study on the gut biome was the most recent research that the study authors examined. While they noted that dysbiosis of the gut was noted in people with depression, anxiety disorders and IBS, they clarify that the studies so far suggest that this dysbiosis is not caused by psychological stress. To the contrary, it appears that psychological stress influences the microbiome in these instances.
The study’s authors conclude that the brain-gut microbiome model could allow doctors and patients to understand IBS and its behavioral comorbidities as a multifactorial disorder. Whereas treatment is currently limited to treating gut symptoms, an interdisciplinary approach combining behavioral, pharmacological, and diet interventions could provide more satisfactory results for IBS patients.
How Genes and Neurons Influence Overeating
In other tummy/gene related news, scientists in Japan have identified a mechanism by which genes suppress overeating and obesity.
Scientists have known for a while that a specific gene–CREB-Regulated Transcription Coactivator 1 (CRTC1)--suppresses overeating and obesity in humans. The deletion of the gene is associated with overeating and obesity. However, the way in which CRTC1 suppresses obesity has not been understood.
Researchers at the Graduate School of Human Life and Ecology at Osaka Metropolitan University noted that mutations in another gene called MC4R are associated with obesity, and furthermore, that MC4R is only expressed by certain neurons in the brain. They hypothesized that the expression CRTC1 in these neurons would suppress obesity, counteracting the MC4R mutations.
The researchers developed a strain of mice that expressed CRTC1 normally–except in the neurons where MC4R was expressed. The mice did not overeat or develop obesity when fed a standard, healthy diet. There was no difference between their body weight and that of the control group.
However, the same strain of mice overate and developed obesity and diabetes when raised on a high fat diet.
Professor Shigenobu Matsumura, who directed the experiment, says that the study reveals that the CRTC1 gene plays a role in suppressing the drive to over-indulge sweet or fatty foods.
“We hope this will lead to a better understanding of what causes people to overeat,” he says.
This is a groundbreaking study that could help us combat obesity and diabetes in an analytical, evidence-based way; it also serves as a reminder that medical conditions like obesity are best approached without judgment.
Cyborg Bacteria Might Revolutionize Medicine
Could especially-engineered bacteria/micromachine hybrids help regulate your gut microbiome, or act as an early-warning system for disease? Could they play a role in cancer treatment? It sounds like science fiction, but biomedical science researchers at University of California, Davis say that their recent discoveries could one day lead to “cyborg bacteria” that could manage such things.
Since Robert Hooke discovered the cell in 1665, scientists have been fascinated by how they survive and replicate. The cell’s regenerative properties became an even hotter topic in the 1700s when Abraham Trembley discovered that an entire hydra could regenerate from an amputated segment–no matter how many times it was cut. Trembley’s accidental discovery allowed us to round a corner; it proved that regeneration originated in the cell.
The discovery of stem cells in the latter half of the Twentieth Century spawned an even greater curiosity–not only about the cells themselves, but how we might manipulate them to our advantage.
Science has made great strides since these discoveries; we’ve learned how to engineer tissues to heal injured skin, and even to regenerate organs such as ears.
Currently, cell engineering primarily hinges upon either “remodeling” living cells to perform nonnative functions or creating synthetic cells that can mimic living cells in a limited way. Each approach has benefits and limitations; living cells retain their normal functions, but they also replicate rapidly. Synthetic cells don’t replicate and are easier to control; however, their function is limited.
The UC Davis experiments went with a hybrid approach, using E. coli cells as a “chassis” that they combined with a polymer hydrogel. When exposed to ultraviolet radiation, the hydrogel forms a sort of synthetic extracellular matrix–a network of proteins and other macromolecules that gives the cells structure and provides biochemical support.
These “cyborg cells” seem to represent the best of both live and synthetic cells. While they retain many of their normal, biological functions, the juiced-up E. Coli cells are more resistant to stressors such as high pH environments or exposure to antimicrobials–and they do not replicate.
In tests conducted on tissue samples in the lab, the new cells proved themselves capable of invading cancer cells. In the future, similar cells could be used to deliver cancer treatments to a targeted part of the body, killing more of the cancer while minimizing damage to other tissues.
The researchers are not yet sure what inhibits the cells’ replication, something that must be known before this technology can be applied. They postulate that the hydrogel might inhibit cell growth or DNA replication–possibly both.
The UC Davis researchers coined a new phrase for these special cells, which are neither wholly living nor wholly synthetic–quasi vita, or “almost life” (we’ll ignore the zombie-eque implications of almost-living cyborg E. coli bacteria).
A Newly-Discovered Form of Ice Challenges Our Understanding of Water
It comprises more than half of the human body. It’s the most basic, essential need of any living thing. It’s what makes Earth livable. How much do we really know about water, though?
Water is an interesting chemical. Unlike most liquids, it is less dense in its solid state (ice) than in its liquid state; this is the reason ice floats. Most liquids contract when they freeze–but water expands by about 9%. For something so familiar to us all, so many of its properties remain a mystery.
A team of researchers from University College London and the University of Cambridge have discovered a new kind of ice called medium-density amorphous ice, proving that we know even less about this crucial chemical than we thought we did. This ice had the same density as liquid water, but it more closely resembled water in its solid state. Unlike the crystalline ice we all know and love, amorphous ice’s molecules are loose and disorganized.
Amorphous ice in itself is not a novel discovery. Low-density amorphous ice was created in a lab in the 1930s by condensing water vapor on a metal surface cooled to -110 degrees Celsius. High-density amorphous ice was discovered in the 1980s; it was created by compressing crystalline ice at -200 degrees Celsius.
This MDA ice was created by ball milling; along with steel balls, regular old ice was placed in a metal jar that had been cooled to -200 degrees Celsius. The jar was shaken vigorously; the scientists had expected to find smaller fragments of crystalline ice, but they found instead ice that resembled a fine powder.
When the ice was compressed and warmed up, it released shocking amounts of thermal energy.
On an ice moon such as Jupiter’s Ganymede, where MDA ice might be more common, such properties could drive tectonic forces.
Professor Christoph Salzmann of UCL, the study’s senior author, says, "We know of 20 crystalline forms of ice, but only two main types of amorphous ice have previously been discovered, known as high-density and low-density amorphous ices. There is a huge density gap between them and the accepted wisdom has been that no ice exists within that density gap. Our study shows that the density of MDA is precisely within this density gap and this finding may have far-reaching consequences for our understanding of liquid water and its many anomalies."
On the balance, the news this week has been bold, daring, and new–perfect for the beginning of spring. Enjoy the increasing sunlight (with plenty of SPF), and join us next week for more interesting news.