Most large joints of the body contain cartilage, a substance that is softer and more flexible than bone. Because of its softness and flexibility, cartilage is well-suited to protect the bones as they move across one another. Unfortunately, this softness and flexibility also makes cartilage prone to injury and erosion. In patients with osteoarthritis, forexample, cartilage breaks down to the point that bone rubs against bone,causing pain and disability. Certain injuries can damage the cartilage (i.e.osteochondral lesion), which can essentially have the same effect.
Once the cartilage of joints has become damaged, there is
little that can be done to fix it. Patients may receive steroid injections into
the joint to reduce inflammation, and may rely on pain medications to relieve
the pain and swelling. Short of joint replacement therapy, no treatments can
reverse cartilage damage once it has occurred.
Fortunately, mesenchymal stem cells may soon be able to reverse cartilage defects that arise from osteochondral lesions and osteoarthritis. Wakitani and colleagues took samples of patients’ bone marrow, which contains mesenchymal stem cells. They then used various laboratory techniques to increase the number of stem cells in the sample. Four weekslater, the researchers then reinjected the concentrated stem cells back intothe same patient using their own source of stem cells. The Wakitani groupshowed that stem cell transplantation improved the patient’s clinical symptoms bysix months, a benefit that continued for two years on average. Samples takenfrom the patients 12 months later showed that the damaged cartilage had beenrepaired. In other work, Centeno and co-authors showed that bone marrow-derived mesenchymal stemcells could increase the volume of cartilage, reduce pain, and increase rangeof motion 24 weeks after stem cell transplantation.
Research continues to determine which stem cells are most useful, how many stem cells should be injected, how many injections need to be administered, and how should those stem cells be prepared before they are injected? Nonetheless, certain groups are making great strides in this area. In fact, the recent discovery of human skeletal stem cells promises to accelerate stem cell research into treating disorders of bone and cartilage.
Schmitt et al. (2012). Application of Stem Cells in Orthopedics. Stem Cells International. 2012: 394962
Hyaluronic acid is a naturally-occurring lubricant made by the body to help cushion joints and support a free range of motion. This lubricant can thin over time, resulting from conditions such as injury, obesity, and even natural aging. It manifests as osteoarthritis (OA), also known as degenerative joint disease. While treatment such as physical activity, maintaining a healthy weight, and improving joint mobility through physical or occupational therapy may help, there is no cure for osteoarthritis. Many patients take over-the-counter painkillers to manage discomfort, but in some cases, pain simply doesn’t respond to drugs. In such cases, physicians may recommend hyaluronic acid injections.
Targeted hyaluronic injections, also called viscosupplementation, have been used specifically for OA in the knee and can add to the joint’s existing supply of the lubricant. These minimally-invasive treatments are an attractive alternative for patients who aren’t ready for knee replacement surgery but have not been able to control symptoms through other therapies.
While hyaluronic injections reportedly work well in certain patients, they may be less effective in elderly individuals and those with severe OA. With that said, 30% of people who received the injections were completely pain-free, with results lasting up to two years. For any patient seeking to delay or avoid knee surgery, treatment offered with these and other alternative options are likely worth exploring.
The human skeleton is made up of bone, cartilage, fat, nerves, blood vessels, and bone marrow. While the skeleton is usually strong and vibrant in youth, it changes considerably with age. Many people, especially women, experience demineralization of bone called osteoporosis. Most of us will suffer from painful, stiff, arthritic joints either from osteoarthritis or rheumatoid arthritis or both. While some of the diseases of bone and joints have specific treatments, none of them helps to restore bone and joints to their younger state. If one could reintroduce skeletal stem cells into the body, that could all change. Excitingly, researchers have recently isolated human skeletal stem cells from bone and other tissues.
At first glance, this breakthrough may not seem so surprising. One might wonder: didn’t we already have stem cells that form bone and cartilage? The answer is yes, but with an important caveat. Before researchers recently isolated human skeletal stem cells, the only stem cells that could be used to produce bone and cartilage were rather unpredictable. In addition to bone and cartilage, the mesenchymal stem cells that have been long used to form these tissues could also produce fat, muscle, fiberglass, blood vessel cells, and other tissues. In other words, the stem cells were broadly multipotent and, by extension, could not easily be used for a specific purpose, like mending bone or repairing an arthritic joint. That is why the recent discovery of these particular skeletal stem cells is so important.
The researchers isolated skeletal stem cells from various human tissues, mainly bone. They then used the skeletal stem cells to regrow bone and/or cartilage. Not only did the stem cells produce bone and cartilage in the first animal they tested, but they could retrieve stem cells from that animal and then cause bone to regrow in a second animal. This means that the skeletal stem cells have the capability of reproducing themselves.
The same researchers also discovered that when a skeleton is injured, such as in a bone fracture, the number of skeletal stem cells in that area increases dramatically. This makes sense since these cells are used to repair and regrow bone. It is also a promising result because it suggests that stem cells could be used to accelerate bone and joint healing in humans.
Scientists not directly involved in this research heralded this finding as “an extremely important advance.” However, they also acknowledge that more work needs to be done before skeletal stem cells can be routinely used in patients with orthopedic conditions. Nevertheless, these results are an exciting development in the field of stem cell research and orthopedics.
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.
When Osteoarthritis (OA) sufferers experience stiffness and discomfort in their joints, exercise may be the last thing on their minds. In fact, OA is the leading cause for disability in older adults. Yet, there is compelling evidence that regular exercise can actually help patients manage the pain associated with the disease. One reason is that it helps aid in weight management, which is crucial to minimizing joint strain. Additionally, exercise can reduce OA symptoms, improve functionality, and preserve range of motion.
With that said, exercising to manage OA without causing further discomfort proves to be challenging. For many patients, the solution lies in selecting low-impact exercises that won’t overwhelm joints and cartilage which have already been compromised. Here are some of the best types of physical activity you can incorporate into your care regimen for effective pain management:
One of the healthiest exercises of all, walking requires no equipment and can be done either indoors on a treadmill or outside. For minimized impact, take shorter strides and hold a pace at which you can maintain a conversation comfortably. If you have been sedentary for some time, build up the lengths of your walks in five-minute increments. The Arthritis Foundation recommends performing moderate-intensity aerobic exercise for 150 minutes weekly (30 minutes of exercise, 5 days a week).
If you’re seeking a full-body cardio workout to really get your heart pumping without straining joints, there’s no better exercise than swimming. Beyond doing laps, aquatic exercises in general are beneficial because the buoyancy of the water offsets the weight placed on the joints. Consider taking a pool aerobics class led by an instructor, or head to your local gym to try some solo activities like water walking.
Range of Motion Exercises
Slow, steady range of motion exercises are excellent ways to promote flexibility. When combined with cardiovascular exercises, these exercises can also strengthen muscles and connective tissue. Wall squats, knee extensions, and leg lifts are just a few ways to keep the lower body limber. For the upper body, consider arm circles and overhead reaches to stay flexible throughout the shoulders and back.
Stretching or Yoga
Stretching can help to alleviate pain and stiffness while increasing flexibility and lowering stress. Follow-along yoga videos and classes are ideal because they offer guided routines so participants can ensure they’re completing the stretches correctly. Poses can be modified to accommodate varying degrees of ability, and practicing certain routines regularly can even help to reduce inflammation across all skill levels.
Like swimming, cycling is a low-impact aerobic exercise which can aid in weight management. Indoor stationary cycling is one popular way to maintain fitness year-round, while outdoor cycling on flat terrain may also be a good option for OA sufferers.
While exercise has its advantages for OA patients, it’s important to take note of any discomfort you experience during or after an activity. If you notice increasing pain, stop and talk to your doctor. Medical experts can recommend a routine tailored to your needs, which may include exercises performed under the supervision of a physical therapist.
In a review published in Stem Cell Research & Therapy, Gupta et al. describe the latest advances in the use of bone marrow derived stem cells to treat osteoarthritis. These cells are promising because of their ability to treat the degeneration of cartilage that occurs in the disease. When connective tissue degenerates, natural regeneration is highly limited because there is not a strong presence of vasculature within that tissue. Thus, interventions to deal with the effects of osteoarthritis are needed.
Historically, non-stem cell treatments have been used in attempts to treat cartilage degeneration. Physical therapy, pharmaceuticals, and surgical interventions have all been largely employed. For mild cases of osteoarthritis, combinations of physical therapy and pharmaceuticals have been used to manage pain and minimize inflammation. Unfortunately, because the disease is progressive, this type of approach is only effective in the short-term.
Eventually, steroids or hyaluronic acid are generally used to treat osteoarthritis. The impact of these more aggressive treatments, however, is debated and does not appear to be consistent across patient populations. Once osteoarthritis reaches the advanced stage, joint replacement is the only option for relief.
The use of cell-based therapies to treat osteoarthritis is not a new idea. Cultured autologous chondrocytes have been shown to successfully treat cartilage degeneration for over 15 years. The downsides to this approach are that it is invasive, the positive effects are likely temporary, and there has not been sufficient research conducted to fully understand how well the technique works and how to optimize it.
Bone marrow derived stem cells have the potential to carry the same success rate as the cell-based therapies that have long been used to treat osteoarthritis while also overcoming the limitations of those therapies. There are several advantages of the application of bone marrow derived stem cells in the treatment of cartilage degeneration.
First, these particular cells can be easily isolated. Second, they can significantly expand in culture before being used therapeutically. Third, they have modulatory properties that enable them to reduce inflammation, which is a critical factor in cartilage degeneration. Finally, they secrete factors that have the potential to both prevent further degeneration and facilitate regeneration.
Given the number of reasons that bone derived stem cells should theoretically improve upon current methods for treating the cartilage degeneration that occurs in osteoarthritis, more research will likely be conducted to decipher whether these cells do indeed provide benefits that other treatment options do not. In the case that these cells continue to appear promising for osteoarthritis treatment, research will likely also aim at determining the best protocols for using these cells to ensure the best outcomes for osteoarthritis patients.
To find out more about the new alternative way to manage the symptoms of Osteoarthritis, click here.
Gupta, PK, Das, AK, Chullikana, A, & Majumdar, A. (2012). Mesenchymal stem cells for cartilage repair in osteoarthritis. Stem Cell Research & Therapy, 3, 25-34.