by admin | Nov 19, 2018 | Adipose, Osteoarthritis, Stem Cell Research, Stem Cell Therapy
Bone generally develops via one of two distinct mechanisms: intramembranous ossification and endochondral ossification. In the former case, mesenchymal progenitor cells directly differentiate into osteoblasts that form bone. In the latter case, the mesenchymal progenitor cells first create a matrix of cartilage that then acts as a template to enable the remodeling or development of bone tissue. This process of endochondral ossification is the predominant way that bone is generating during the healing process after bones are broken and fractures are endured. Using stem cells to facilitate this process can, therefore, be beneficial in non-healing bone fractures.
A new study published in Acta Biomaterialia has proposed that adipose tissue can be used in bone generation as a scaffold on which adipose mesenchymal stem cells can expand and allow for endochondral ossification. The researchers showed how adipose tissue could be used in this way, through what they termed Adiscaf, to successfully generate cartilage tissue and eventually bone tissue formation. The bone tissue that formed through this process contained bone marrow elements, further demonstrating the bone’s integrity and the promise of this procedure.
Compared to other strategies for building scaffolding, this strategy appeared successful because by using adipose tissue, the adipose stem cells were exposed to their native environment and therefore likely maintained functions they otherwise may not have. Not only will these findings help to solidify our understanding of how to nurture stem cells and enable them to differentiate in ways that can be therapeutically applicable, but they also specifically show how adipose tissue may be able to be used to generate a bone organ through endochondral ossification. Future research will likely help to clarify how these findings can be applied to patients to improve bone healing.
by admin | Nov 14, 2018 | Stem Cell Research, Stem Cell Therapy
Evidence has been accumulating for years showing how stem cells can serve therapeutic functions. Much of this research focuses on how stem cells can be applied to damaged tissue to help regenerate the area. Because stem cells can differentiate into a wide variety of cell types, they can be widely utilized to repair distinct types of tissue. However, a recent paper published in the World Journal of Stem Cells has described how stem cells can also be used to carry therapeutic agents to tissues and organs to help with regeneration.
Stem cells are good candidates for delivering genes, proteins, and small molecules to areas of interest because they have an innate ability to migrate to sites of injury. One challenge for using stem cells for this type of therapeutic delivery is how to load the stem cells with the therapeutic agents. There are pros and cons for the techniques that have been investigated.
Polymeric nanoparticles, are FDA approved and are versatile, uploaded efficiently, and biocompatible. However, it is hard to control the release of the therapeutic agent from the stem cells. Magnetic nanoparticles are not associated with high levels of toxicity and are efficient with loading. However, they can induce oxidative stress in carrier cells.
Silica nanoparticles have quick uptake, are non-toxic, stay within cells for a long time, and are versatile. However, their tendency to stay within cells for a long time can sometimes be a disadvantage when the agent needs to be cleared.
Liposomal nanoparticles are relatively easy to manufacture and are versatile in their therapeutic agent delivery. However, these nanoparticles are less efficient at uptake and need higher concentrations of the therapeutic agent loaded, which can be toxic to cells.
Once stem cells are loaded with bioactive molecules, there are a few ways that they can be guided toward target organs. For instance, they can be systemically infused so that they can migrate to their target areas trough blood flow.
Further research will help to clarify how well stem cells can be used to help deliver therapeutic agents to damaged or impaired tissue. Investigation into the different nanoparticles, stem cells, and potential therapeutic applications will help us better understand the extent to which stem cells can be used in regenerative medicine.
by admin | Oct 18, 2018 | Stem Cell Research, Stem Cell Therapy, Studies
A couple of weeks ago, scientists published findings showing that implanting human stem cells that are embedded within the engineered tissue can lead to the recovery of sensory perception in rats. The recovery of sensory perception is also accompanied by healing within the spinal cord and the ability to walk independently. The stem cells used in this experiment were collected from the membrane lining the mouth.
These results help demonstrate the potential for stem cells to help with spinal cord injuries but also point to the utility of combining stem cells with other factors to enhance their therapeutic effects. In this case, the researchers used a 3-dimensional scaffold to enable stem cells to attach and to stabilize them in the spinal cord. By adding growth factors, such as human thrombin and fibrinogen to the engineered tissue scaffolding, the researchers also increased the chances that attached stem cells would grow and differentiate.
The researchers compared the effects of their stem cell implants in paraplegic rats with the effects of adding no stem cells. Whereas the control rats who did not receive stem cells did not experience any improvement in mobility or sensation, 42% of the rats that did receive stem cells became better at supporting their weight on their hind limbs and at walking.
While these results are pre-clinical and do not apply directly to humans, the researchers conclude that further research is warranted. Given the positive impact of stem cells on the spinal cord in animals, it is reasonable to assume that stem cells may also benefit the human spinal cord. Further research will help clarify whether these stem cells can be adequately used to help treat patients with paraplegia.
by admin | Oct 11, 2018 | Stem Cell Research
Myocardial infarction, also known as heart attack, can be a devastating or even deadly event. It occurs when blood flow in one or more coronary arteries is blocked. Since coronary arteries supply blood to the heart muscle, a blockage in a coronary artery prevents oxygen and nutrients from reaching heart tissue.
While the heart can sustain short periods of time without oxygen or nutrients, heart cells become dysfunctional and die if blood flow is not restored within several hours. While clot-busting drugs, percutaneous intervention (PCI), and balloon angioplasty have provided a way to restore blood flow to the heart during a heart attack, once heart cells die there is no way to bring them back. Since most heart tissue is cardiac muscle, dead heart tissue cannot participate in the contraction or squeezing of the heart during a heartbeat. Thus, people who have survived a heart attack are often left with poor heart function (e.g. congestive heart failure).
Stem cell researchers have begun to question whether heart tissue destroyed during a heart attack is necessarily gone forever. Research is beginning to show that stem cells given after myocardial infarction are able to improve the squeezing power of the heart. By extension, stem cell treatment is able to improve the abilities heart to pump blood throughout the body.
Researchers initially assumed that it was the stem cells themselves that became new heart cells, replacing dead and dysfunctional heart tissue. While there is evidence that this occurs, it seems that stem cells play an even bigger role in heart tissue repair than simply becoming new heart cells. Stem cells release small packets of a material called exosomes and microvesicles. Exosomes and microvesicles hold proteins, cytokines, chemokines, growth factors, DNA, messenger RNA, and micro RNA. Researchers now believe that these materials hold the true power of stem cells in cardiac repair and regeneration.
Various types of stem cells produce exosomes that could potentially help repair a damaged heart. While cardiac stem cells may seem like an obvious source for these exosomes, induced pluripotent stem cells and mesenchymal stem cells are also capable of releasing exosomes that are potentially beneficial in cardiac repair.
Stem cells—or more accurately the exosomes contained within the stem cells—help repair damaged heart tissue in several ways. Stem cell-derived exosomes contain factors that promote the survival of vulnerable heart cells and cells that are dysfunctional after a heart attack (but not dead). Exosomes also help new blood vessels to form in and around the damaged heart muscle in a process called angiogenesis. These new blood vessels deliver oxygen, nutrients, and molecules that help support the growth and function of heart tissue. Exosomes also appear to promote a healthy immune system response after a heart attack, rather than a destructive inflammatory reaction. In other words, the materials found in exosomes guide the immune system to clear away damaged tissue without creating extensive fibrotic (i.e., tough, nonfunctional) tissue.
While most clinical trials thus far have studied the effects of stem cells directly infused into humans after myocardial infarction, exosomes are rapidly becoming the focus of future clinical trials in this area.
by admin | Sep 27, 2018 | Heart Failure, Stem Cell Therapy
People with heart failure may have trouble breathing, walking, and having a normal life. Current treatments for heart failure are aimed at making the healthy heart tissue pump harder (e.g. digoxin). On the other hand, treatments largely ignore dead heart tissue because there A myocardial infarction, better known as a heart attack, occurs when blood flow through the coronary arteries to the heart is blocked. This usually occurs when a blood clot forms in a coronary artery. Since the heart is a highly active muscle, it requires a constant supply of oxygen and nutrients to maintain its pumping function. When the heart muscle is starved of oxygen, as is the case during myocardial infarction, heart cells become dysfunctional. If blood flow through the coronary arteries (which carries oxygen to the heart) is not restored soon after a heart attack begins, those dysfunctional heart cells will die.
When heart tissue has been destroyed by a heart attack, patients are usually left with poor heart function. This can lead to congestive heart failure. One way to determine whether someone who has had a heart attack has suffered lasting heart damage is to perform an echocardiogram, or simply an “echo.” By performing an echo, doctors can estimate the heart’s ability to pump blood by measuring left ventricular function.
has been no known way to rescue it. With the discovery and use of stem cells, however, there is a chance that scientists may be able to rescue dead heart muscle and improve cardiac function.
In a study, researchers blocked the coronary arteries of experimental animals to cause myocardial infarction. Four weeks later, they injected either bone marrow-derived stem cells or adipose-tissue-derived stem cells into the heart. Impressively, blood flow significantly improved to the heart and heart function. Treated animals had substantially higher left ventricular ejection fraction, essentially reversing heart failure a full month after a heart attack. Shockingly, the researchers found that stem cells appeared to salvage dead heart tissue, meaning that the size of the damaged area was smaller after treatment.
While these incredible results will need to be replicated in humans, this research represents an exciting breakthrough in cardiology and regenerative medicine. The stem cell approach may be able to help patients who have had a heart attack, but could not get medical treatment in time to remove the clot.
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