The loss of bone mass and the weakening of the bones are natural consequences of aging, but this process starts around the age of 30, so it’s not only the elderly that are at risk for falls and fractures due to bone resorption.
Some of the factors that cause the decrease in bone mass density can be controlled, but others are out of one’s control. Smoking for example can be avoided, and one can practice strength exercises to keep their bones strong, but an inadequate intake of calcium, the use of asthma medications, as well as the changes in hormone levels that occur in older adults can speed up the weakening of bones.
Also, this process is accelerated by an inadequate intake of vitamin D, the lack of exposure to gravity and hypoparathyroidism, all these factors favoring the resorption of bone. When the tissue is broken down faster than it can be renewed, the density of bones starts to decrease and they become more porous, fragile and prone to fractures.
Although there are a series of conventional treatments that can help in improving bone density in osteoporotic patients, people who suffer multiple fractures, major bone trauma or individuals injured during natural disasters may require a different approach. In such cases, the use of stem cells could speed up bone repair and eliminate the risk of tumor formation.
STEM CELLS FROM BONES AND SKIN, USED FOR BONE RECONSTRUCTION
Scientists from the Gladstone Institutes have discovered a way to stimulate bone reconstruction using proteins produced by stem cells. Instead of grinding up bones from cadavers in order to extract the proteins and growth factors needed for stimulating the growth of new tissue, the researchers have extracted bone-forming proteins from stem cells.
After they treated the proteins in the lab, they injected the substances into muscle tissue of mice, in order to facilitate bone growth. The injected proteins were effective in creating new bone tissue, so there is hope that this method may be a good solution for humans as well. Unlike current treatments, the use of stem cells is safer as it doesn’t involve the transplant of cells or tissues from cadavers or other donors, so the risk for these cells to be rejected is much lower and the risk for tumor formation is very low also.
The study published in Scientific Reports concluded that proteins extracted from stem cells could be a consistent and reproducible source material for tissue regeneration . This isn’t the first study to support the use of stem cells for orthopedic purposes. In 2001, another paper published by Dr. Ranieri Cancedda in the New England Journal of Medicine described the use of autologous bone marrow cells in the repairing of large bone defects.
The research showed that the osteoprogenitor cells derived from stem cells were effective in supporting the integration of macroporous hydroxyapatite scaffolds in damaged bones. Three patients were treated using this method and CT scans taken 6 months afterwards showed good callus formation and integration of the interfaces in all patients .
Even more interesting were the results obtained by a team of scientists from the National Institutes of Health, Bethesda, USA, who managed to grow new bone from stem cells harvested from skin cells. The paper was published in the Cell Reports journal, the harvested skin cells being reprogramed into equivalents of embryonic stem cells . The obtained iPSCs were treated in lab conditions to differentiate into precursors of bone cells, then transplanted the obtained cells into monkeys, on a ceramic scaffold.
The implanted cells grew new bone on top of the scaffolds, researchers finding no sign of tumor. According to the researchers, this technique has two great advantages: the stem cells harvested from patient’s own cells are less likely to be attacked by one’s immune system, and iPSCs can be generated from any individual.
Although the use of stem cells for speeding up the integration of implants in damaged bones is not new, scientists are now looking to develop these methods further, so as to obtain stem cells that can promote bone regeneration and regrowth once transplanted to humans.
If you’re one of those people who is really fond of their beauty sleep, or who never compromises when it comes to getting their full eight hours per night, now you have one more reason to make a full night’s sleep a priority .
A study by scientists at the German Cancer Research Center have found that while environmental stress can damage the DNA in adult hematopoietic stem cells, a good night’s sleep can keep these cells young, contributing to a youthful appearance and preventing cancer.
Healthy sleep patterns lower the risk of DNA damage in stem cells
According to German researchers, under normal conditions a high number of different types of adult stem cells exists in a state of dormancy inside the human body, but they cannot divide, therefore cannot be used for tissue regeneration. This state of dormancy protects the stem cells from DNA damage, keeping us younger and preventing premature aging .
Yet, increased levels of stress in all its forms—from chronic infections to environmental stress—can trigger a rapid division of stem cells, kicked into gear as the body needs to repair its damaged tissues. In such conditions, the dormant stem cells go from no activity to very high activity in a short interval, and this rapid change forces them to increase their metabolic rate and synthesize new DNA.
Doctor Michael Milsom, who coordinated the German study, says that having to simultaneously execute such complicated functions increases the risk of DNA damage in the stem cells, reducing the ability of tissues to repair themselves and speeding up aging [1, 3].
Moreover, scientists believes that the accumulation of stress-induced damage in the stem cells can make one more prone to cancer. Experiments conducted in this study showed that cell division that takes place under stress leads to an increased production of reactive metabolites. These substances can damage DNA, causing the death of stem cells or leading to mutations that can contribute to cancer.
Understanding how to prevent the aging of stem cells or DNA mutations and damage could be the key to delaying the aging process and reducing the risk of developing certain forms of cancer, concludes Dr. Trumpp, co-author of the study’s research paper.
Protect your stem cells for healthy skin and a youthful appearance
The study is not the only one to prove a connection between sleep and the health of stem cells. Another paper, published in the journal of Cell Research by scientists from the University of California Irvine, showed that circadian rhythms regulate the metabolism of skin stem cells, and that getting enough sleep during the night can maintain healthy cell division, nurturing stem cell differentiation .
Although the study was conducted on mice, the findings are worth exploring further to determine whether a disruption in the healthy circadian rhythm can alter the normal function of stem cells, leading to accelerated aging.
Professors Andersen and Gratton, who conducted the Irvine study, focused on the effects stem cells have on the skin, already knowing that stem cells found in the dermal layers protect the skin and help in the repairing the epidermis after injuries.
Using innovative technologies, the two researchers measured the metabolic state of stem cells, discovering that the circadian clock does regulate one form of intermediary metabolism in target cells. According to researchers, it’s the same component of metabolism that creates oxygen radicals, harmful substances that can cause DNA damage.
The results of this study suggest that maintaining healthy sleep patterns can prevent DNA-damage in skin stem cells, while an altered internal clock could lead to the accumulation of damage in these cells, accelerating aging.
What seemed an impossible medical challenge a few years ago might turn into a doable task with the help of bone marrow stem cells. Several trials are testing the use of adult stem cells in heart disease, hoping to identify a viable solution for repairing the cardiac tissue damaged by heart attacks, coronary artery disease and other similar ailments.
OBTAINING CARDIAC MUSCLE CELLS IN THE LAB
Despite the huge amount of information available out there and the numerous health programs that aim to prevent heart diseases, these conditions remain the most common cause of death in Europe, with heart attacks dominating the list. According to statistics, around 7 million people worldwide suffer from heart attacks each year, the damage being in lots of cases irreversible.
Given the amazing results obtained with stem cell therapies in conditions like leukemia or lymphoma, it was natural for scientists to intensify their research efforts in this niche, in order to see whether the potent stem cells can also be used for repairing damaged hearts. While some studies have showed promising results, others have found no improvement after transplanting stem cells to patients with heart conditions.
The biggest challenge in these cases seems to be the reprograming of stem cells obtained from other tissues into cardiomyocytes. Cardiomyocites are the cells that form the cardiac muscle, and although for a very long time scientists believed that the heart does not produce any stem cells, it’s been shown that the body does produce new cardiomyocytes each year, but the number decreases with age.
The discovery that the human heart produces new cells each year has created hope and encouraged researchers to try to find out where the new cardiac cells come from and how this process is controlled inside the body. The ultimate goal was to identify those mechanisms that could be replicated in lab conditions, so as to obtain new heart cells viable for transplantation in patients with heart diseases.
Although the existence of heart stem cells has not been confirmed yet, it is possible to obtain cardiomyocytes in the lab, from stem cells obtained either from embryos or from iPS cells (induced pluripotent stem cells). The latter can be obtained by reprogramming skin cells that are taken directly from the patient, reducing the risk of transplant rejection.
One of the biggest problems here comes from the fact that bone marrow cells and other adult stem cells can be reprogramed to repair a specific tissue, but if they are treated in lab conditions until they differentiate to specific cells like those in the cardiac tissue, the risk of tumors and rejection increases.
On the other hand, if the pluripotent stem cells from embryos or the iPS cells are transplanted into the heart, they might differentiate and give birth to a multitude of cells. It is impossible for one to control the type of cells formed by stem cells in the body once transplanted, if those cells were transplanted before specializing.
STEM CELL STUDIES ON THE DAMAGED HEART SHOW MIXED RESULTS
Existing studies show that treating heart conditions with stem cells is more difficult than using stem cells therapies for other tissues and organs. A trial done in Belgium, Switzerland and Serbia on 45 patients aimed to treat heart attack victims with stem cells. The injected cells led to no complications and were guided to become cardiac cells, scientists highlighting the safety and feasibility of the procedure .
Other studies showed little to no effect after the transplantation of stem cells. Cardiologist Darrel Francis at Imperial College London published a review study in BMJ, examining 133 reports of 49 randomized clinical trials that aimed to treat heart attack or heart failure patients with stem cells. According to his paper, more than 600 discrepancies were found in these trials, so the results cannot be considered relevant .
Francis’ study showed that the 5 trials that had no discrepancies reported no improvement in the left ventricular ejection fraction (LVEF) after stem cell treatment, while the 5 trials with the most numerous discrepancies reported a significant improvement (+7.7%) of LVEF after stem cell therapy.
While scientists are still trying to answer whether stem cells are a solution for damaged heart tissue, some stories report that patients who received this treatment after a heart attack saw a clear and dramatic improvement in their health state and heart function. One of these patients is Jim Dearing of Louisville, who was among the first patients to receive heart stem cells after suffering two heart attacks and heart failure. His heart was functioning normally one year post treatment .
What’s certain for now is that results of these studies are mixed, and researchers will need to further investigate the use of stem cells from bone marrow in patients with heart diseases.