A team of researchers from the 12 de Octubre University Hospital of the Community of Madrid and the Complutense University of Madrid has been working for years on the development of biomaterials to treat bone defects. His latest research, published in Acta Biomaterialia, one of the most prestigious journals in this field, represents significant progress towards his goal: eliminating the need to use autografts and cadaver bone grafts in orthopedic surgery. Although these are still the most effective methods, they have limitations and side effects.
Treatment of bone defects that cannot self-heal is a global challenge in orthopedic surgery. In this context, according to Lorena García Lamas, orthopedic surgeon and traumatologist at Hospital 12 de Octubre and researcher at the i+12 Research Institute, “bone autograft continues to be the best solution to treat defects due to its osteoconductive, osteoinductive and osteogenic capacity. , that is, its ability to stimulate the formation of new bone.”
However, as García Lamas explains, its use is limited by several factors, such as morbidity in the donor area, the limited amount of tissue available from the patient himself, the prolonged surgical time and the risk of blood loss during the operation. After autograft, allografts (cadaver bone grafts) are the most used substitutes, coming from bone banks. These may offer structural support but do not promote new bone formation due to the preparatory processes necessary to reduce the risk of infection or disease transmission.
Given this situation, there is a need in the field of tissue engineering to develop “tissue equivalents” that can fulfill the function of the autograft without the limitations that come with its use. Recent research on mesoporous glass represents an important step in that direction, offering a viable and potentially revolutionary alternative in the treatment of bone defects.
Search for biocompatible, bioactive and resorbable materials
To avoid the negative consequences of autografts and allografts, researchers have been searching for years for compatible biomaterials that can replace them. These materials are introduced into the bone defect to maintain space, provide mechanical support and interact with bone tissue, facilitating new bone formation.
It is essential that these biomaterials are biocompatible, meaning that they must have favorable reactivity and not be encapsulated by the body as a foreign object. Instead, they should promote bone formation directly on their surface.
The first synthetic materials implemented in the sixties were solid. However, over the past few decades, they have evolved to be bioactive and degradable. Furthermore, with the advancement of 3D printing, they can now be designed with a porous three-dimensional structure, which allows the growth of blood vessels and the colonization of the material by osteoforming cells, thus facilitating the formation of new bone.
There are two large families of bioactive materials: bioceramics based on calcium phosphate, due to their composition similar to bone, and bioactive glasses. In studies carried out in vivo by Dr. Lorena García and in vitro by the team of Dr. Antonio Salinas, from the Faculty of Pharmacy of the Complutense University of Madrid and the Research Institute of Hospital 12 de Octubre, both types of materials have proven to be biocompatible, bioactive and resorbable to varying degrees. This means that they are able to integrate with the receiving tissue and eventually disappear completely or partially once they have fulfilled their supporting function.
Solution: mesoporous glasses
Bioactive glasses have been perfected to become the current mesoporous glasses, which were the subject of the latest in vivo study by Dr. García and Dr. Salinas. According to Salinas, these are the synthetic materials with the greatest bioactivity, that is, those that begin to form bone in less time. In addition, they have macroscopic pores and nanopores, all of the same size and highly ordered, which makes them ideal for adding ions with therapeutic activity and loading them with biomolecules and biologically active drugs, such as strontium or osteostatin. These elements promote bone formation and healing.
Salinas points out that, compared to the synthetic materials currently used, “our biomaterials have a much higher bioactivity than any other synthetic biomaterial. It can take only eight hours for bone formation to begin, in contrast to the three to seven days required for a material already considered highly bioactive. “It’s a real record.”
Although these biomaterials have not yet reached the level of bone autografts, both researchers agree that they achieve rates of new bone formation higher than those of the biomaterials in use. Although these biomaterials were designed years ago and have passed all clinical trials and regulatory approvals, Salinas concludes that bioactive mesoporous glasses enriched with therapeutic ions, biomolecules and cells must still overcome the long process necessary to be used in patients.
Source: Hospital October 12
