News Article | March 17, 2016
Stem cells come in several types, but a new variety developed by researchers possess just half of the genes normally found in a human genome. These newly-created haploid stem cells could lead to new therapies for a range of maladies, as well as new tools to assist in genetic screenings, researchers state. Humans carry 46 chromosomes, detailing our genetic makeup. However, these new stem cells, like reproductive cells, holds just 23 chromosomes. Human beings inherit a total of 46 chromosomes, with half of the total coming from each parent. Researchers triggered unfertilized human egg cells into division. The DNA within the structures were then marked with a fluorescent dye, and haploid cells were separated from the more-common diploid cells containing 46 chromosomes. Investigators found the haploid cells were able to develop into a wide range of cells, including those seen in muscles, nerves, and other body systems. This new research could answer one of the most basic questions biologists still have about higher life forms, including human beings. "This study has given us a new type of human stem cell that will have an important impact on human genetic and medical research. These cells will provide researchers with a novel tool for improving our understanding of human development, and the reasons why we reproduce sexually, instead of from a single parent," said Nissim Benvenisty of the Azrieli Center for Stem Cells and Genetic Research at The Hebrew University of Jerusalem. These are the first human cells ever shown to be capable of cell division while possessing only half the normal amount of genetic code. Haploid cells are easier to study than diploid cells, as there is no "back-up" to "correct" changes made by medical researchers and caregivers. Stem cells are currently being employed in a wide range of treatments for diseases and disorders. This new technique could also be used to treat blindness, diabetes, and other disorders, as the genetic code is a perfect match for the egg cell donor. They might also, one day, be employed in the quest for treatments for reproductive issues in patients, researchers believe. Development of the new haploid stem cell was profiled in the journal Nature.
News Article | April 21, 2016
A plant-based polyphenol promotes the migration of Mesenchymal Stem Cells (MSCs) in blood circulation and accumulates them in damaged tissues to improve wound healing, scientists have found. It is anticipated that the results will be used for stem cell treatments for cutaneous disorders associated with various damage and lesions.
Goodfellow, a graduate student in the University of Georgia's Regenerative Bioscience Center, has developed a unique approach of marrying stem cell biology and 3-D imaging to track and label neural stem cells. His findings were published in the journal Advanced Functional Materials. Using microscopic iron beads and a chicken egg, he and his colleagues were able to label neural stem cells and watch them for multiple days using magnetic resonance imaging—without harming the cell. Very little is known about the unusual behavior of neural stem cells after experimental treatment. Understanding their whereabouts, keeping them safe from the body's own immune system and tracking the intended destination for repair in a noninvasive manner is the next important step in regenerative medicine therapy. "The unknown is that big 'black box' when people inject neural stem cells and have no idea where they go, or what they do-it's pretty invasive and inaccurate," said Steven Stice, a Georgia Research Alliance Eminent Scholar and director of the Regenerative Bioscience Center who is housed in the College of Agricultural and Environmental Sciences. The question remains, he said, of whether injecting neural stem cells to restore damaged neurons and allowing the body to heal as it is meant to naturally really delay the onset of symptoms, such as Alzheimer's and Parkinson's diseases. To answer that question, Goodfellow painstakingly labeled neural stem cells with extremely small iron beads and then transplanted the cell into a chicken embryo. "We went to great pains to prove and demonstrate that our labeling method does not harm the stem cells," said Goodfellow, who started as an undergraduate in Stice's lab while majoring in animal and dairy science in the UGA College of Agricultural and Environmental Sciences. "If we are altering transplanted stem cells that we hope will be an effective treatment, then it's a moot point if we do it blindly." Before proving that neural stem cells could be tracked with MRI, the RBC research collaboration, which included Qun Zhao, Luke Mortensen and Gregory Simchick, first had to determine if the iron beads were harmful to the neural stem cells. For 14 days, they tracked and compared live cells and evaluated the fate of derived cells based on their gene expression profile. "We had to take it to the next level and be able to follow the process through for a period of time," Stice said. "No one has really been able to follow neural cells at any great depth to the level of specificity that we were able to do." The findings focus mainly on neural stem cells, but Goodfellow sees potential for their use with mesenchymal stem cells. "One novel aspect of this iron nanoparticle is the iron center covered in synthetic polymers," Goodfellow said. "The covering can be manipulated to show up in green, red or a spectrum of colors with fluorescent microscopy and MRI for a multitude of regenerative therapies-but the surface is what helps it to not harm the cells." The dextran coating used around the nanoparticle increases the nanoparticles biocompatibility, allowing for a larger loading capacity and the protection of a stable environment, he said. In addition to developing a chick model and applications for toxicology testing in the near future, Goodfellow and his team hope that this project may finally shed some light on the uncertainty surrounding neural stem cells and the great therapeutic promise for healing patients after stroke, traumatic brain and spinal cord injuries. "The hope is that this research will get stem cells to clinical applications faster, even if we are just doing rodent studies," he said. "If we are able to see that the cells are surviving and integrating and not adversely affecting the animal, then the likelihood of us getting through clinical trials and onto a real therapy is a lot greater and a lot faster." More information: Forrest T. Goodfellow et al. Tracking and Quantification of Magnetically Labeled Stem Cells Using Magnetic Resonance Imaging, Advanced Functional Materials (2016). DOI: 10.1002/adfm.201504444
Abstract: Large or slow-healing wounds that do not receive adequate blood flow could benefit from a novel approach that combines a nanoscale graft onto which three different cell types are layered. Proper cell alignment on the nanograft allows for the formation of new blood vessel-like structures, as reported in of Tissue Engineering, Part A, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free for download on the Tissue Engineering website until May 26, 2016. Tae Hee Kim, Soo Hyun Kim, PhD, Kam Leong, PhD, and Youngmee Jung, PhD, Korea Institute of Science and Technology, Korea University, Korea University of Science and Technology (Seoul, Korea) and Columbia University (New York, NY), describe the nanoscale topography and triculture technology they used to create a microenvironment that mimics what occurs in normal tissue and can promote angiogenesis. They demonstrate how the shape, width, and depth of the nanograft all affected the behavior of the cells and the formation of stable capillary-like tubular structures. In the article "Nanografted Substrata and Triculture of Human Pericytes, Fibroblasts, and Endothelial Cells for Studying the Effects on Angiogenesis," the researchers describe how this technique could be applicable for treating wounds that do not heal well naturally. "The combination of advanced materials and polycellular administration is opening new paths to the all-important requirement for angiogenesis in tissue engineering," says Co-Editor-in-Chief Peter C. Johnson, MD, Principal, MedSurgPI, LLC and President and CEO, Scintellix, LLC, Raleigh, NC. About Mary Ann Liebert, Inc./Genetic Engineering News Mary Ann Liebert, Inc., publishers is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research, including Stem Cells and Development, Human Gene Therapy, and Advances in Wound Care. Its biotechnology trade magazine, GEN (Genetic Engineering & Biotechnology News) was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's 80 journals, books, and newsmagazines is available on the Mary Ann Liebert, Inc., publishers website. About the Journal Tissue Engineering is an authoritative peer-reviewed journal published monthly online and in print in three parts: Part A, the flagship journal published 24 times per year; Part B: Reviews, published bimonthly, and Part C: Methods, published 12 times per year. Led by Co-Editors-In-Chief Antonios Mikos, PhD, Louis Calder Professor at Rice University, Houston, TX, and Peter C. Johnson, MD, Principal, MedSurgPI, LLC and President and CEO, Scintellix, LLC, Raleigh, NC, the Journal brings together scientific and medical experts in the fields of biomedical engineering, material science, molecular and cellular biology, and genetic engineering. Tissue Engineering is the official journal of the Tissue Engineering & Regenerative Medicine International Society (TERMIS). Complete tables of content and a sample issue may be viewed online at the Tissue Engineering website. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Most people would be happy to get rid of excess body fat. Even better: Trade the spare tire for something useful — say, better-functioning knees or hips, or a fix for an ailing heart or a broken bone. The idea is not far-fetched, some scientists say. Researchers worldwide are repurposing discarded fat to repair body parts damaged by injury, disease or age. Recent studies in lab animals and humans show that the much-maligned material can be a source of cells useful for treating a wide range of ills. At the University of Pittsburgh, bioengineer Rocky Tuan and colleagues extract buckets full of yellow fat from volunteers’ bellies and thighs and turn the liposuctioned material into tissue that resembles shock-absorbing cartilage. If the cartilage works as well in people as it has in animals, Tuan’s approach might someday offer a kind of self-repair for osteoarthritis, the painful degeneration of cartilage in the joints. He’s also using fat cells to grow replacement parts for the tendons and ligaments that support the joints. Foremost among fat’s virtues is its richness of stem cells, which have the ability to divide and grow into a wide variety of tissue types. Fat stem cells — also known as adipose-derived stem cells — can be coerced to grow into bone, cartilage, muscle tissue or, of course, more fat. Cells from fat are being tested to mend tissues found in damaged joints, hearts and muscle, and to regrow bone and heal wounds. The stem cells in fat share the medical-worthy spotlight with a few other cells. Along with the fat-filled adipocytes that store energy, fat tissue has its own blood supply and supporting connective tissue, called stroma. The stroma contains blood cells, immune cells, endothelial cells that line the inner surface of blood vessels and pericytes, which line the outer surface. These other fat-derived cells are proving to have therapeutic value as well. Plastic surgeon J. Peter Rubin, also at Pitt, says that the multitalented cells found in fat could prove to be the ultimate body repair kit, providing replacement tissue or inspiring repair of body parts that can’t mend themselves. Much of the research — more than a decade of studies — has been in lab animals, but a few applications are being tested in human volunteers. Current clinical studies under way aim to provide replacement tissue to treat chronic wounds and diabetic sores, or conditions such as Parkinson’s disease, multiple sclerosis, chronic obstructive pulmonary disease and type 1 diabetes. Most clinical studies use the simplest approach: Harvest cells from a patient, then inject them in a single procedure. In more complex approaches still in lab and animal testing, various cells in fat are extracted and manipulated to create custom treatments for worn-out or damaged tissues or to generate blood flow after a heart attack or replace bone in large fractures. Questions remain, however, about how the cells do their regenerative magic. Scientists and regulators still have plenty to figure out, such as what cell characteristics work best for each application. Stem cells can develop into various cell types, which makes them the focus of studies that aim to replace cells that fail because of disease, accident or age. Stem cells taken from embryos are more versatile than other types of stem cells, but their use is controversial. For that reason, researchers have studied stem cells from sources other than embryos, including bone marrow, muscle and blood. Fat tissue comes from the same embryonic tissue as bone marrow, a traditional stem cell source, so scientists reasoned that fat might contain similar cells. In 2002, UCLA researchers discovered stem cells in human fat. They were surprised to find vast quantities. Stem cells make up 2 to 10 percent of fat tissue. A cubic centimeter of liposuctioned fat (about one-fifth of a teaspoon) yields 100 times as many stem cells as does the same amount of bone marrow, Tuan says. And fat cells are easy to harvest — much easier than bone marrow. One pound of fat removed from a patient’s abdomen can yield up to 200 million stem cells, a more than adequate supply for treatments. Why fat produces so many stem cells isn’t clear, but Rubin points out that fat tissue serves several important functions. In addition to storing and releasing energy, it helps insulate and protect the body’s internal organs. “Like most tissues in the body, fat has a reservoir of stem cells to replenish cells as they die off or create new cells in response to growth or the need for more cells,” he says. Fat produces so many stem cells, in fact, that for some applications — such as tissue-replacement or “fat grafting” — there’s no need to grow more of them in the lab. Once harvested, liposuctioned material is treated with enzymes to remove cells from the surrounding tissue, then put into a centrifuge to separate the stem cells from other cell types. In about an hour, the stem cells are ready to be injected back into the patient to plump skin or round out fat tissue lost to injury or disease. Rubin has used this method to treat patients who have lost tissue during breast cancer surgery or have been injured in war. His lab is conducting a clinical trial on the use of fat stem cells to plump up tissue at the site of an amputation to improve the comfort and fit of a prosthetic arm or leg or to make it easier to tolerate sitting for long periods in a wheelchair. Already, Rubin’s team has treated five military patients, extracting fat from each patient’s abdomen and injecting the stem cells back into the patient at the injury site. He and other scientists think that the fat stem cells remodel tissue by releasing growth factors and communicating with surrounding cells in their new location — sending and receiving signals through chemical cues. As a result, the stem cells enhance the growth of new fat tissue and boost blood supply to surrounding tissue. Over a period of several weeks, the cells he injects form a mound of fat tissue, allowing patients to fit a prosthesis or sit without pain. So far, all of the patients have benefited from the stem cell injections, he says, though his group is still working on how much to inject for each patient. Fat is an organ with a complex assembly of cells. In addition to fat cells, or adipocytes, and blood vessels, fat tissue contains stem cells, pericytes (cells that stabilize blood vessel walls), pre-adipocytes (precursors to fat cells), macrophages (immune cells) and endothelial cells, which form the inner lining of blood vessels. Other applications require manipulating cells in the lab, placing fat stem cells in a specific environment — and sometimes putting mechanical pressure on them — to direct the cells to transform into certain cell types. Tuan’s group at Pitt places fat stem cells on scaffolds that help guide the growth of the cells, developing treatments to regenerate anterior cruciate ligament tissue or to repair rotator cuff injuries and Achilles tendon ruptures. Injury to ligaments and tendons is common, especially among athletes, but tears or worn-down areas generally don’t heal completely by themselves. Efforts to create substitute tissues have largely failed, Tuan says, because re-creating the structure of a tendon or ligament remains a challenge. Tendons are the cables that connect muscle to bone, allowing arms to rotate at the shoulder, knees to bend or fists to clench. Cells in tendons, called tenocytes, line up along long fibers of collagen, creating molecular bridges that reach across and intertwine with collagen cables to help give them strength and flexibility. This structure allows tendons to be stretched up to 15 or 20 percent beyond their original length and snap back into shape. Tuan’s group has discovered a trick for turning fat stem cells into tenocytes that grow in the same organized way. In 2013, the researchers outlined the method in Biomaterials. To replicate the structure of natural tissues, the scientists created scaffolds of biodegradable nano-sized fibers. Fat cells were then combined with bovine collagen and placed, or seeded, into the scaffold. The tiny fibers interacted with the stem cells, sending and receiving instructions that guided the stem cells’ growth. Over seven days, as the stem cells differentiated into tenocytes, the scientists applied mechanical force on the ends of the scaffold — pulling the structure to keep the cells under tension just like a natural tendon would do during motion. By tugging on fat stem cells, Tuan says, the group can create replacement tendons that are strong, stiff and resilient, like natural human tendons. Tuan’s group is also exploring 3-D printing to create artificial cartilage from fat stem cells. Cartilage is a flexible tissue that serves as padding between bones, allowing knees, fingers, hips and shoulders to move freely. When cartilage wears down, the result is osteoarthritis, a painful condition that affects one in four people, often those over age 65. Once cartilage is damaged, it continues to deteriorate, forming what Tuan calls “potholes.” Over time, the potholes grow, eventually reaching the bone. The standard solution is a joint replacement. In the United States, more than 1 million people get knee or hip replacements each year. Tuan calls the process “rebuilding the road.” The invasive procedure requires surgically replacing the joint with plastic and metal parts that generally last 10 to 15 years. Because an increasing number of people get new joints in their 40s or 50s, many require more than one round of surgery. “But there’s a limit to the number of times you can do that,” he says. Tuan’s 3-D printing method builds thin layers of fat stem cells into a custom-sized scaffold to create new cartilage in the size and shape needed. The “ink” is made of fat stem cells plus gelatin, which consists of proteins found in living tissue. The scientists chemically modify the gelatin so that the ink remains fluid during printing. Once printed, the material is irradiated with light so that enzymes in the mixture form bonds, cross-linking to create stiffer, cartilage-like material. The procedure has been used to create cartilage implants for rabbits and goats. Animals that once hobbled were able to hop, trot and otherwise move about, according to a report last August in Frontiers in Bioengineering and Biotechnology. “Because the engineered cartilage is a living tissue … unlike a metal or polymer implant, it is expected to continue to grow into its natural shape and function once it is implanted into the joint,” Tuan says. “No replacement is therefore necessary.” Still, it’s not the ideal solution, Tuan admits. “The problem is that’s not how tissues are formed,” he says. “Tissues form when cells migrate to a place, make themselves at home and build their own support structure, or matrix.” His group is now devising ways to allow fat stem cells to set up their home right at the site of the pothole. The vision is to create a minimally invasive procedure, giving doctors a tool they can thread through a catheter to print the fat-derived stem cell cartilage at the site of the damage, inside the joint. Fat stem cells could then settle in and multiply directly in the joint. Additional arthroscopic instruments, also under development in Tuan’s lab, will allow physicians to guide the injection and smooth out newly printed cartilage to create a perfect fit that closely resembles the real thing. So far, each step in the new approach has been developed. The next step is to tie all the pieces together in animal studies. The body does a better job of healing broken bone than healing cartilage. But if the fracture is large or a significant amount of bone is lost, the bone may not heal. In such cases, surgeons can take bone from another part of the patient’s body, or use bone from a cadaver, to fill in the gap. Biomedical engineer Warren Grayson of Johns Hopkins University says more than 1 million bone replacement procedures are performed each year in the United States, often after accidents or tumor removal. The surgery is invasive and carries risks of rejection, infection and lingering pain. A better option, Grayson says, is to help patients grow bone from their own fat cells. Because the bone-growing material comes from the patient’s body, the grafts are less likely to get rejected than cells from donor tissue. What’s more, the bone may later grow with the patient, potentially eliminating the need for multiple surgeries in children who receive grafts but still have growing to do. Since 2010, Grayson’s team has been growing bone from liposuctioned fat and successfully implanting the bone in animals. Stem cells taken from fat are placed in a bioreactor, an incubator--like device that nourishes cells as they grow on a scaffold for five weeks. Added nutrients and growth factors help the cells transform into bone cells. Already, fat stem cells have been used in a few trials to help regenerate bone in people. In 2004, German doctors successfully used stem cells collected from a 7-year-old’s fat, along with other cells, to repair damage to her skull. Five years later, scientists at Cincinnati Children’s Hospital Medical Center seeded a bone graft with fat stem cells to replace a teen’s missing facial bones. In the case of the teen, fat stem cells were injected onto a scaffold from donor bone. But such bone grafts require multiple surgeries and don’t come with a ready blood supply to nourish the new bone as it grows. Grayson’s group aims to make the repair process easier on the patient. He and his team are growing fully functioning bone — with its own blood supply — from fat. Each graft can be custom-designed, using 3-D modeling and printing, to fit precisely where needed. His team is experimenting with different formulas — and two different cell types from fat — to find the best ways to form all the cell types needed. More recently, his group tested fat-derived stem cells against bone marrow cells in creating new bone. The fat stem cells outperformed the bone marrow stem cells. The findings, published in the September 2015 Stem Cells, show that in the presence of specific growth factors over a period of weeks, fat stem cells produced more calcium and bone mineral deposits per cell than did the bone marrow stem cells. The current challenge is to produce tissue that has its own system of blood vessels to supply nutrients needed for the new bone to grow. In the Journal of Biomedical Materials Research Part A in 2014, Grayson’s group outlined a method for printing bone grafts with internal pore structures that would allow blood vessels to grow through the graft while maintaining the structure of the scaffold. The team is now investigating ways to help spur such growth by seeding the structure with endothelial cells or blood-vessel forming cells from fat. Endothelial cells and other cells in fat are the lifeblood of efforts to develop a patch that can be applied to damaged heart tissue following a heart attack. Stuart Williams, a cardiologist at the University of Louisville in Kentucky, is creating a cell-infused patch seeded with a mixture of smooth muscle cells, endothelial cells and blood cells, all obtained from fat tissue. “This fat tissue contains a huge number of blood vessel–forming cells,” Williams says. The idea for the patch, outlined in 2013 in Stem Cells Translational Medicine, is to harvest fat from a patient, pull out the vessel-forming cells and seed the cells onto a biomaterial that can be immediately implanted. The whole process, from start to finish, will take about an hour. The fat-cell patch works particularly well to promote healing in very small blood vessels, Williams says, a feature that may be especially beneficial for women, who often have more problems with their small blood vessels and fewer problems with the large ones. Rats treated with a patch seeded with endothelial cells from fat tissue two weeks after a heart attack (MI SVF) show more new blood vessels (green) in the damaged area of the heart, compared with untreated rats (MI) and rats treated with an unseeded patch (MI Vicryl). Four weeks after treatment, the MI SVF rats had better heart function and less tissue damage. Total vessel density (vessels per square millimeter) was determined through staining methods. “The interesting thing is, there’s really no stem-ness to these cells at this point,” Williams says. “They don’t have to differentiate. All they have to do is reconnect with each other to form these new blood vessels.” The patches could be created in the operating room during surgical bypass, he says. Such patches might also be applied to other areas of the body, such as legs, hands or feet, where patients have limited blood flow, Williams says. In wounds that aren’t healing well, cells could be injected directly into the area to promote blood flow and healing. While Williams has shown his technology works in animals, he hasn’t yet tested it on people. Getting the federal go-ahead to pursue studies in humans remains a challenge for the heart patch and many other new applications of fat cells. Current guidelines issued by the U.S. Food and Drug Administration allow trials for treatments in which cells are harvested and injected back into the same patient in a single surgery. But the FDA, and regulatory agencies worldwide, are wrangling with questions on how to test and assess new types of therapies in which cells are grown on scaffolds or manipulated in the lab. Questions remain, for example, on how to best handle cells in the lab to ensure safety and purity of a product, and how to package and transport products once they are made. Fat stem cells, for example, may change or dedifferentiate when growing in a lab dish, sitting on a warehouse shelf or even following injection into the body, Tuan says. Later this year, the FDA plans to hold a public hearing to solicit comments from scientists, manufacturers and others on how to proceed. Meanwhile, scientists in the field agree that the potential for fat to do good is here. “Fat may actually be a natural storehouse of regenerative cells,” Williams says. “When applied correctly, these cells may someday help repair bodies on an as-needed basis.” This story appears in the March 19, 2016, issue with the headline, "Fat as a fixer."