For orthopedic dentists, the problem of bone tissue deficiency at the site of the proposed implantation is very relevant. In this case, bone grafting is used – method of restoring the bone tissue of the jaw.
Today, there are many techniques for bone reconstruction. About one of them – with the use of mesenchymal stem cells– Andrey Alekseevich Orlov, dentist, doctor of medical sciences, professor of maxillofacial surgeon, implantologist – in his report "Influence of transplantation of autologous mesenchymal stem cells from adipose tissue on the course of the osteogenetic process".
Statistical studies show that about 40% of patients in dental clinics require preliminary bone grafting of the jaw for successful implantation.
The method of bone grafting consists in introducing bone material into the required area of the jaw. Bone material can be either natural (allogene – selected from the bone tissue of a donor, autogenous - selected from the patient's bone tissue, xenogenic – selected from the bone tissue of an animal), and artificial (special materials that promote the formation of one's own bone) .
We have conducted research aimed at solving an important problem in traumatology and orthopedics – it stimulates the process of osteogenesis. We are talking about the use of mesenchymal stem cells (MSCs), obtained from the patient's adipose tissue, in autotransplantation of bone material.
Relevance of the study
One of the urgent problems of modern theoretical and clinical medicine is the development of new high-tech medical technologies, which undoubtedly include methods based on the use of cell technologies.
Since A.Ya. Friedenstein described human bone marrow mesenchymal stem cells, they are considered as the main sources of the cell pool for the constant renewal and regeneration of bone tissue.
Their first use was investigated in the repair of long-term non-healing fractures in elderly patients. Over the past time, cellular technologies have stepped far forward. New methods and sources for obtaining stem cells, including from adipose tissue, have been developed, which is relevant in the light of this study.
As a result of numerous studies already carried out, subtle mechanisms of MSCs and those interactions that are carried out with their direct participation have been revealed at the molecular level. MSCs have been found and isolated from adipose tissue, skeletal muscles, ligaments, trabecular bone, and a number of other types of tissue.
These data support to some extent the concept of the existence of a reserve in the form of stem cells in the adult body throughout the postnatal life of a person.
The study we have conducted is aimed at solving an important problem of modern traumatology and orthopedics – stimulation of the osteogenetic process in case of bone deficiency, including in the area of the alveolar process of the jaw, which is important for orthopedic dentistry.
Material and methods of research
As you know, one of the significant problems of orthopedic dentistry (dental implantology) is the lack of bone tissue in the area of the alveolar process. The use of MSCs from adipose tissue in the future may prove to be an effective tool for solving this problem.
If it is not possible to perform surgery using microvascular technology, if the patient has autoimmune diseases, this technique can be very useful.
The study was conducted in two groups – in the first one, the autograft was introduced using MSCs, in the other – MSCs were not applied.
The first surgical stage of the study included the harvesting of an autograft, the second stage – its transplantation to the recipient bed in the jaw area. Next, a 2-fold introduction of MSCs was performed.
When analyzing histological pictures, we aimed to assess the bone formation process in the space between the autologous material and the maternal bone by determining the intensity of the bone formation process according to the following indicators:
- active formation of new bone trabeculae;
- histological characteristics of osteoblasts (in terms of manifestation of their functional activity);
- according to the presence of deposits of newly formed bone trabeculae on bone fragments as manifestations of osteogenetic activity;
- according to the degree of maturation of newly formed bone structures at the stages of the experiment.
Research results
The study showed that on the 21st day the leading process in the area of autotransplantation of bone material on the jawbone with inoculation into the area of surgical intervention of an autograft of an autogenous culture of MSCs obtained from adipose tissue was the process of active osteogenesis in the area of transplantation, moreover, as in the area of the maternal bone, and along the edges of the autograft.
Between these zones of active osteogenesis there was a connective tissue layer, which, as it were, demarcated these two areas of cellular osteogenetic activity.
It can be assumed that this space is the area where the osteogenetic activity of lipogenic MSCs manifests itself to the maximum extent. At the same time, their immunomodulating and anti-inflammatory potential also fully affects.
In the comparison group, where there was no osteogenesis-supporting effect of MSCs, osteogenetic activity was either absent or extremely low.
In addition, there were also cytological signs of low competence of cellular elements. They, as a rule, were small and irregular in their location at the edges of the bone trabeculae, which in this group of observations were themselves extremely sparsely and irregularly presented in the area of contact of the autologous bone graft with the maternal bone.
It is very important to note that on the 120th day after autotransplantation with the use of MSCs, we observe a slowdown in the process of osteogenetic activity, because telomerase ceases to be produced. On the 180th day, in the area of contact between the autologous graft and the maternal bone, a bone substrate is formed, which is already a single whole. There was an overlay on the graft, its complete remodeling. At the same time, osteogenetic activity is practically no longer manifested.
This concept postulates the existence of a mechanism that limits the number of cell divisions at the ends of chromosomes (telomeres) due to the absence of telomerase on them. This mechanism plays an important role in stabilizing the process of changing cell generations, causes “aging” cell populations, and also prevents the immortalization of cells and, accordingly, their malignancy.
Thus, bone grafting using mesenchymal stem cells from adipose tissue significantly accelerates the process of bone strengthening and increases its efficiency.
Video clip with a detailed description of a scientific study on the osteogenetic process in bone tissue reconstruction using MSCs, which was conducted under the guidance of Professor A.A. Orlova, you can see here:
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