Treatment of osteoarthritis does not exist so far. However, one innovative nanotechnological approach can help the therapeutic agents to penetrate deeper into the affected cartilage and stay active longer.
Damaging the cartilage in the joints, osteoarthritis affects approximately 26 million people in the United States. Sometimes the condition begins with mechanical (or disease) damage to the joint. In other cases it occurs due to wear caused by many years of operation. But whatever the reason, at the moment there is no way to stop the progression of the disease. The only available are drugs to relieve the associated pain.
With the ageing and obesity of the population (both factors increase the risk of developing osteoarthritis), the problem is becoming more serious. In addition, since pain is the predominant symptom of osteoarthritis contributes to the crisis of opioid dependence. Therefore, the search for innovative ways to treat the condition segadreamcast as ever.
The problem of drug delivery
The issue of engaged researchers from the Massachusetts Institute of technology in Cambridge. They studied ways of using nanotechnology to enhance the effect of the experimental drugs for the treatment of osteoarthritis. Last week they published their results in the journal Translational Medicine.
For many years, scientists have invented razlichayushchiesya against osteoarthritis. Some of them proved effective in animal trials, but to date, none of the drugs have not proven helpful to patients.
The authors of the new study believe that the lack of any proposed remedies were ineffective in delivering drugs. This is due to two main reasons. First, the joint is no blood supply, and this means that professionals need to do to inject the drug directly into the joints. Secondly, lymphatic drainage facilitates the rapid removal of the compounds injected into the joints. To overcome this obstacle, researchers have focused on the development of the method of delivery and storage of medicines in the joint for a longer time, and dip them deeper in the cartilage.
The medicine on which they focused, became insulin-like growth factor 1 (IGF-1), a compound that has shown promise in some clinical trials. The substance promotes the growth and survival of chondrocytes, which are cells that form healthy cartilage.
Tiny spheres
To transport IGF-1 researchers have developed a spherical nano-molecules, which consists of many branches, called the dendrimersemanating from a Central core. Each branch ends in a positively charged area, which is attracted to the negative charge on the surface of chondrocytes. Molecules also have a movable polymeric branch, which periodically closes and neutralizes the positive charges. The researchers attached molecules of IGF-1 to the surface of this sphere and injected the drug into the joints of rats.
As soon as these particles enter the body, they bind to cartilage, and lymphatic drainage is unable to remove them. From there they penetrate into the tissue. However, the scope join is not forever, as in this case, they were stuck on the surface of the cartilage. Flexible polymer branch sometimes covers the charge, allowing the molecule to move and dive deep into the tissue.
The study’s lead author Brett Geiger, a graduate student at mit, says:
We found the optimal range of charge, the material was able to bind the tissue and to disconnect for further diffusion.
When IGF-1 is introduced into the chondrocytes, it triggers the release of proteoglycans or content of the cartilage. IGF-1 also promotes cell growth and reduces the speed of their death.
The extension of therapeutic possibilities
The researchers introduced this hybrid molecule in the joints of rats. She had a half-life of 4 days (the time necessary for the drug to decrease to half of its original volume), about 10 times more than when the researchers administered only IGF-1. It is important to note that the therapeutic effect lasted for 30 days.
Compared with rats that did not receive the drug, those who had decreased the damage to the joints. In addition, there was a significant decrease in inflammation. Of course, the cartilage of the rat is much thinner than in humans: its thickness is about 100 µm, whereas the thickness of a human approaching 1 millimeter. But in a separate experiment, the scientists proved that these molecules are able to penetrate the thickness that is relevant to humans.
This is only the first phase of testing, exploring the use of these molecules for drug delivery to the cartilage. The team plans to continue in the same direction and to study other chemicals, including drugs that block inflammatory cytokines and nucleic acids, including DNA and RNA.
Experts confirm that the data obtained are encouraging. At the moment there is no other system of medicine delivery, which can stably influence the metabolism of chondrocytes in situ throughout the thickness of the articular cartilage.
Although the new method is in its infancy, in the end, his appearance could mean that doctors will be able to significantly slow the course of osteoarthritis due to a two-week or monthly injections.