Early exposure to a broad range of bacteria could help improve intestinal health later in life.

Your Microbiome as a Baby May Influence Your Intestinal Health Today

Bedtime story to foster your infant’s brain development? Check. Warm bath to clean her? Check. Lullaby to soothe her? Check. Probiotics to improve her gut health for the rest of her life? Probably worth looking into.

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 In the United States, one in five people struggle with digestive issues, including incurable chronic diseases such as inflammatory bowel disease (IBD) that can require removal of the colon or small intestine. However, a
 <a href="http://www.genomebiology.com/2015/16/1/211">
 recent study
 </a>
 in Genome Biology suggests that the best approach might be to fix things before they are broken.


 Bacterial exposure during infancy may affect gut health into adulthood, according to researchers at Baylor College of Medicine. “Many, many diseases appear to be influenced by various environmental exposures during critical periods of early development,” said Dr. Robert Waterland, who collaborated with lead author Dr. Lanlan Shen and a team of researchers.


 The researchers looked at changes in mice’s digestive systems during infancy. Within the digestive system, the gut microbiome contains an ecosystem of bacteria influenced by diet that helps the body break down food and fight off infections. Intestinal epithelial cells that line the small intestine absorb nutrients and produce a mucus layer that protects them from the caustic, bacteria laden environment inside.

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 Intestinal epithelial cells turn over every four days and are continually replaced by intestinal stem cells that are tucked away tiny pocket-like glands of the small intestine called crypts. These stem cells are the only cells in the digestive system that are maintained from infancy to adulthood, Dr. Waterland said.


 The DNA of intestinal stem cells is a blueprint for new intestinal epithelial cells. It can be changed through a process called DNA methylation, where methyl (CH 3 ) groups are tacked onto the DNA in different patterns that alter gene expression. The researchers focused on changes in DNA methylation patterns during the suckling period that lasts from birth until mice transition to solid food, equivalent to the breastfeeding period in humans. “This is a beautiful period where mice are undergoing dramatic environmental changes,” Dr. Shen said.


 The researchers compared “germ-free” mice that lacked a gut microbiome to regular mice with a normal gut microbiome and found that the intestinal stem cells of the germ-free mice had less DNA methylation, which resulted in slow production of new intestinal epithelial cells and a thinner mucus layer. However, when they reintroduced gut bacteria during infancy, DNA methylation in those stem cells increased, which restored proper functioning and improved intestinal health. The key to their finding is that bacteria in the gut microbiome only influence methylation patterns in intestinal stem cells during the suckling period early in development. Once that critical period is over, the DNA in intestinal stem cells is set for life.


 So what does all of this this mean for your infant? Dr. Shen and Dr. Waterland are hoping to use dietary bacteria to adjust the gut microbiome during infancy to improve long term gut health. In the system they are developing, you could test your infant’s feces, which contain DNA from old epithelial cells that have sloughed off, and compare the methylation patterns to an index of infant gut maturity. If something looks off in the DNA methylation patterns, you could give your infant probiotics to correct the issue, potentially sidestepping intestinal problems down the line. The next step in their research is to identify the specific bacteria strains that restore DNA methylation patterns in intestinal stem cells and pinpoint the period when restoration is most successful.


 Dr. Pia Pannaraj, a pediatric infectious disease specialist at Los Angeles Children’s Hospital, conducts related research on the role of breast milk in establishing the infant gut microbiome. She points to the gut microbiome as a factor in certain allergic and autoimmune diseases as well as IBD and obesity. She agrees that probiotics are a viable strategy for correcting imbalances in intestinal bacteria early in life and that early development should be the focus of infant gut microbiome research.


 “It’s important to know the changes over the first year of life, particularly during infancy, because that is when the immune system is learning how to be an immune system,” she said.

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 <a href="https://www.flickr.com/photos/wallyhartshorn/59475685/">
 Wally Hartshorn/Flickr (CC BY-NC)
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In the United States, one in five people struggle with digestive issues. A recent study in Genome Biology suggests that the best approach might be to fix things before they are broken.

Open-Ocean Fish Achieve Camouflage With Rotating Crystals Embedded In Their Skin

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 Soldiers often cloak themselves in camouflage print to hide in open spaces, and
 <a href="http://www.bio.utexas.edu/research/cummingslab/pdfs/Brady-Science-2015.pdf">
 a recent study
 </a>
 in
 
 Science
 
 suggests that some fish accomplish an even more impressive trick to conceal themselves in the open ocean. These fish have nanoscopic crystals in their skin that help them blend in against backgrounds of polarized light, a type of light invisible to humans, but visible to other fish.
 

 All light travels through the air as waves that vibrate in and out perpendicular to the direction they are moving, and visible light waves that we use to see the world vibrate in many different planes. However, polarized light waves are special—as they travel, they only vibrate in a single plane.
 
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 Visible light waves become polarized when they hit the surface of the ocean—only waves oscillating in a single plane make it through—which means that while our eyes interpret the open ocean as a uniform blue expanse, this is not the case for marine species with specialized receptors that detect variations in polarized light. “It would probably look something like walking through a kaleidoscope,” said principal investigator Dr. Molly Cummings from the University of Texas.
 

 She explains that open-ocean fish are highly exposed, and as the sun moves across the sky throughout the day, the main plane for polarized light waves tilts with it, creating a changing and varied polarized background that fish have to blend in against. This does not occur in shallow water or coastal habitats because coral reefs or sand disrupt light waves and prevent them from becoming polarized.
 

 Dr. Cummings worked with lead author Dr. Parrish Brady to determine how open-ocean fish species camouflage themselves in this unprotected, chaotic environment. Their study in Curacao compared two open-ocean species to two coral reef species in the Carrangidae family of fish.
 

 Dr. Brady built a video polarimeter, a specialized underwater camera that records information about the polarized light field. Each live fish was secured in a net at the center of an X-shaped platform suspended just beneath the surface in the open ocean. The platform rotated 360° every 3 minutes while the camera, attached to an arm on the platform, collected data on how much the fish contrasted with its polarized background at different angles.
 

 They found that the open-ocean species hid themselves by minimizing contrast with their polarized background, while the coral reef species remained highly visible. The researchers interpreted this as evidence that polarized camouflage evolved after the species diverged from a common ancestor and moved to different habitats.
 

 The researchers also looked closely at the skin of the open-water species, which contains tiny, flat crystals called platelets. “They’re what are responsible for the silvery sheen on the fish skin,” Dr. Brady said. “The color produced by these platelets is very much correlated with how they are arranged in the skin.”
 

 In open-ocean fish, the elongated, six-sided platelets orient themselves parallel to the fish gills, and continually rotate 360° along their long axis to match the changing polarized background. The fish are particularly well camouflaged when viewed from directly in front or behind, which may help them evade predators or stealthily chase down prey.
 

 Dr. Sonke Johnsen, who studies marine camouflage at Duke University, is not entirely convinced by the study, and notes that polarized vision is most common in crustaceans and cephalopods. “The fish they’re looking at are pretty big, powerful predators themselves in many cases, and they are preyed upon by other fish. Because of the way eyes are designed in vertebrates compared to invertebrates, polarization vision is vanishingly rare among fish.” He thinks more research is needed.
 

 Dr. Cummings’ project was funded by a basic research grant from the Office of Naval Research, for finding biological phenomenon that may have military applications. While she is not at liberty to discuss links between her work and the Navy, it is easy to envision how the research could be used.
 

 “Presumably other scientists could take our biological properties and turn that into a material feature that we could put on submarines or other things that we float in the ocean, to have them not be picked up by satellites that might use polarization,” she said. “Our research drives home the point that nature has solved a lot of problems for us, and we can really benefit from paying attention and understanding their intricate, complex solutions.”
 
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 Photo credit:
 <a href="https://www.flickr.com/photos/kubina/131669842">
 Jeff Kubina / Flickr (CC BY-SA 2.0)
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Years of impact can wear down cartilage to the point where it needs replacement.

3D Woven Synthetic Cartilage Could Help Your Knees Replace Themselves

With each step, cartilage in your knee absorbs impact, reduces friction, and keeps everything functioning smoothly. After millions of steps, it may be no surprise when that cartilage begins to wear out.

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 Cartilage degeneration often results in arthritis, which can reduce mobility and cause chronic pain. It cannot be repaired, but research on replacement tissues may soon offer a viable alternative.


 “If you have arthritis in your hip or knee, we don’t just have to fix a little pothole, we can resurface the entire joint,” said Dr. Farshid Guilak, a Duke University researcher whose team is working on a technique to replace large swaths of existing cartilage with new tissue grown from your own stem cells. The team is currently testing their approach on large animals, and Dr. Guilak expects to begin human testing within four to five years, if not sooner.


 Cartilage is a strong, flexible, fibrous tissue that exists in a few different forms throughout your body. Articular cartilage, the focus of this work, coats the ends of bones in your major weight-bearing joints including your knees and hips. It consists of cells called chondrocytes that produce large amounts of a tough, resilient matrix made mostly of collagen fibers.

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 Articular cartilage continually withstands huge amounts of force—three to five times your body weight during normal activity and ten times your body weight during exercise. It absorbs impact and reduces friction between bones as you sit, walk, run and jump. But over time, that repetitive force can cause it to break down.


 “Cartilage is a tissue that has no blood supply, no nerves, no lymphatic system, so it actually has a very poor ability to repair itself,” Dr. Guilak said. Today, he said, more young people are dealing with degenerating cartilage due to sports injuries and obesity, and people in their 40s and 50s with damaged cartilage must decide between limping around for decades or opting for a knee replacement likely to wear out within 20 years, well before the end of their lives.


 Dr. Guilak and his team have developed a three-dimensional woven scaffold—a dense material made of woven fibers that is strong and flexible—that’s similar to cartilage but is also porous. They print the material on a 3D weaver, which is similar to a 3D printer, but can produce a fiber reinforced structure.


 Stem cells are harvested from a patient’s bone marrow or liposuction waste, where they are plentiful and easy to obtain. The cells are exposed to a cocktail of growth factors, hormones and vitamins that converts them into cartilage cells and they can then be injected into the woven scaffold.


 The scaffold, now full of cartilage cells, is covered with a tough, gel-like material designed to reduce friction and withstand wear, and the entire synthetic cartilage structure is placed inside the patient.


 The synthetic cartilage functions like the real thing, and over the next year or two, the cartilage cells begin to produce their own matrix, which replaces the synthetic parts of the structure. The end result is new, completely natural cartilage that was developed from your own cells.

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 If the current trials in large animals are successful, the researchers will move on to a long term animal study followed by human trials to test for safety and efficacy, Dr. Guilak said.


 Other groups are also involved in cartilage research, including one led by Dr. Eben Alsberg at Case Western Reserve University and Dr. Ali Khademhosseini at Harvard University. Dr. Alsberg called the work at Duke “excellent,” but pointed out that he and his team are taking a slightly different approach. They plan to inject stem cells into water-based gels called hydrogels and then investigate how different factors affect cartilage development. They will adjust factors that influence gel stiffness, cell growth and attachment, and mechanical compression until they find the optimal combination to promote cartilage formation.


 “The big goal is to take cells…and allow them to do what they’re evolved to do—make tissues,” Dr. Khademhosseini said.


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 <a href="https://www.flickr.com/photos/roberto_ferrari/4008501292/">
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Catherine Caruso

Articles

Your Microbiome as a Baby May Influence Your Intestinal Health Today

Open-Ocean Fish Achieve Camouflage With Rotating Crystals Embedded In Their Skin

3D Woven Synthetic Cartilage Could Help Your Knees Replace Themselves

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