Patent Description:
Stem cells are specialized cells that can self-replicate during cell division and differentiate into other cell types. Stem cells are classified as embryonic stem cells (ESC), induced pluripotent stem cells (I PSC) and mesenchymal stem cells (MSC).

MSCs are adult stem cells and can be obtained from humans and animals. MSCs are named in this way because they can differentiate into special cells that develop from the mesoderm. Human mesenchymal stem cells (hMSC) are multipotent cells that are self-regenerative, multipotent, adherent, easily obtainable, widely cultured under laboratory conditions, and can differentiate into mesodermal line cells such as osteocytes, adipocytes and chondrocytes.

The minimum criteria determined by the International Society for Cellular Therapy (ISCT) for the characterization of hMSC are listed as follows: These cells; a. Must adhere to the plastic surface, b. CD14, CD34, CD45 and HLA-DR markers should not express, while CD73, CD90 and CD105 are expressing, c. Must have an ability to differentiate in vitro into osteocytes, adipocytes and chondrocytes. These characteristics are applied to all MSCs. In the state of the art, hMSCs were first isolated from the bone marrow and then obtained from various tissue sources such as adipose tissue, amniotic fluid, amniotic membrane, limb bud (embryo limb bud) menstrual blood, peripheral blood, placenta and fetal membrane, salivary gland, skin and foreskin, synovial fluid endometrium, dental pulp, umbilical cord and Wharton jelly. hMSCs can be cultured in media specifically produced for themselves for the long-term. MSCs have been used in the treatment of various diseases for a long time with their immunomodulatory properties, the factors they secrete, the immunreceptors that they organize their own microenvironment, and their differentiation.

MSCs obtained from the placenta and the umbilical cord in the patent document numbered <CIT> and the ones obtained from wharton jelly in the patent document numbered <CIT> are some the methods of obtaining only when there is a pregnancy.

In the state of the art, various invasive methods are employed to obtain hMSCs. Employing the invasive method to obtain hMSC is undesirable for the comfort of the subject. For example, while using MSCs taken from the bone marrow of the subject to obtain MSC from bone marrow; in MSCs to be obtained from adipose tissue, it is usually applied by removing fatty tissue pieces from the belly region with liposuction (fat removal method) or small operations. MSCs to be obtained from dental pulp must be obtained from deciduous teeth, however this can be only in childhood, it is not suitable for obtaining stem cells in adults. It is obtained from wisdom teeth or other teeth in later ages. However, it is not suitable for the comfort of the subject since this process requires an operation. MSCs to be obtained from tissues such as limb bud, placenta and fetal membrane, Wharton jelly and umbilical cord, amniotic fluid, amniotic membrane, foreskin are also not a source of stem cells which can be used in adult ages as they need to be taken at a certain time. Still, stem cell sources such as synovial fluid, endometrium and salivary gland are also sources of MSCs in which cells can be obtained by invasive methods. In the prior art, it has been demonstrated that obtaining MSC from peripheral blood is performed by obtaining cells with both hematopoietic and MSC characteristics from the blood by Ficoll gradient cell precipitation method. However, with the invention, peripheral whole blood is not used in obtaining MSC. Platelet Rich-fibrin (PRF) tissue is used for obtaining MSC. In the prior art, whole blood was used directly for obtaining MSC and it was shown that there is both hematopoietic and MSC stem cell in the blood. However, PRF is completely different from whole blood in terms of both content and structure. PRF is a fibrin matrix that mainly contains thrombocyte and cytokines. With the invention, the presence of MSC is also shown inside. The presence of MSC was reported in tissue containing many connective tissue stromas in the body. Blood is not an organ/tissue containing stroma. Although peripheral blood is required initially for obtaining PRF, PRF has a completely different anatomical, physiological and molecular structure from peripheral blood. Thus, there is no known prior art for obtaining MSC from PRF. In the prior art used for obtaining MSC from blood, which can be considered the closest, among the obtained cells, those with adherence properties were evaluated with CD105, KIT and SLAMF1 markers, the morphology of the cells was found acceptable, and their differentiation ability into the only osteoblast and osteoclast cells was examined. Therefore, since there was no study that fulfilled the criteria determined by the I SCT, the cells adhered to the plastic surface were evaluated as cells exhibiting the MSC character. Platelet Rich-Fibrin (PRF) refers to a fibrin matrix portion obtained by specific centrifugation technique of Peripheral blood. This portion is enriched in thrombocyte, is different from the content of peripheral blood in terms of both cellular and cytokines. Although the presence of CD34+ hematopoietic stem cells in Platelet Rich-Fibrin (PRF) is known in the state of the art, Platelet Rich-Fibrin (PRF) is not available for use for mesenchymal stem cell production.

The primary aim of the invention is to obtain mesenchymal stem cells with blood taken directly from the venous vein without affecting the comfort of the subject without any invasive procedure.

With the invention, it is aimed to obtain thrombocyte-rich fibrin tissue and to obtain mesenchymal stem cells from this tissue by taking only <NUM> tube of blood from an easily obtainable source, without requiring any surgical operation.

With the invention, mesenchymal stem cells were obtained from thrombocyte-rich fibrin tissue, and the produced cells were also prepared in clinically usable production conditions (GMP grade) and made clinically applicable.

Platelet Rich-Fibrin (PRF) means fibrin matrix structure which is obtained from natural blood tissue, comprises abundant thrombocytes and leukocytes in its structure. With blood obtained from volunteers; Mesenchymal stem cells (MSC) were obtained from PRF (<FIG>). For this purpose, <NUM>-<NUM> of venous blood (preferably <NUM>) was firstly collected from each subject with a syringe and transferred into glass-covered plastic tubes. PRFs were obtained by centrifuging the tubes for <NUM> minutes at <NUM> rpm according to a known method. Then, PRFs were washed with PBS. Under the sterile conditions, they were mechanically cut into small pieces as possible with a bistoury under the laminar flow cabinet. The obtained small pieces were firstly transferred to D-Lysine coated flasks and were cultured in incubator with <NUM>- <NUM>% CO<NUM> at <NUM> by adding <NUM>-<NUM>% by volume of human serum (preferably <NUM>), animal serum or <NUM>-<NUM>% by volume of penicillin-streptomycin (preferably <NUM>%) without serum; <NUM>-<NUM>% by volume of L-glutamine (preferably <NUM>%); inorganic salts, such as calcium chloride, potassium chloride, magnesium sulfate, sodium chloride, sodium bicarbonate, sodium phosphate; amino acids, such as L-alanine, L-arginine, L-asparagine-H2O, L-aspartic acid, L-cystine, L-cysteine-HCl-H2O, L-glutamic acid, L-glutamine, glycine, L-histidine, L- isoleucine, L-leucine, L-lysine, L-methionine, L-phenyl alanine, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine; vitamins, such as L-ascorbic acid, biotin, D-Ca pantothenate, choline chloride, folic acid, i-inositol, niacinamide, pyridoxal HCl, riboflamine, thiamine HCl, vitamin B12; alpha MEM medium, which is a finished commercial medium containing all of D-glucose lipoic acid, sodium pyruvate, phenol red substances. One day later, the contents in the D-Lysine coated flask were transferred to the empty flasks. During the <NUM>-<NUM> days following the primary culture, cells were monitored under an inverted microscope without moving much, and then the medium was changed. The medium was changed at least twice a week by monitoring the cells regularly. In the passaging process, when the cells were <NUM>-<NUM>% confluent, the cells were removed from the plastic surface to which they were adhered by using <NUM>-<NUM>% by volume of Trypsin-EDTA solution (preferably <NUM>%), and after an average of <NUM> minutes of centrifugation at <NUM>-<NUM> (preferably <NUM>) for <NUM>-<NUM> minutes, the pellet was plated in new culture plates with the new medium. Upon reaching the therapeutic dose, the cells were optionally taken into glass vials at <NUM> × <NUM><NUM> (±<NUM> × <NUM><NUM>) cell/ml in a physiological fluid, such as physiological saline at a dose determined according to the disease to be used, for example; in <NUM> of physiological saline or in a physiological fluid which can be administered intravenously. Clinically useful mesenchymal stem cells were made ready for use in orthopedic-skeletal system diseases including graft versus host disease, heart diseases, brain diseases, liver diseases, cancer, jaw diseases, kidney and urinary system diseases, gynecological diseases, infectious diseases, eye diseases, osteoarthritis, osteonecrosis which have MSC indications and all dermatological cases having an anti-aging purpose.

In the characterization of PRF-MSCs to be performed by flow cytometry, cells exhibiting phenotypic MSC characterization in vitro at the <NUM>. passage were used. For this, <NUM>×<NUM><NUM> cells were removed from the culture plates, centrifuged and incubated with BD Stem Flow hMSC kit (BD cat no: <NUM>) containing CD11b, CD19, CD34, CD44, CD45, CD73, CD90, CD105 and HLA-DR markers according to the manufacturer's instructions after resuspended in DPBS. Then, the presence and ratios of CD markers were detected by using Navios (Beckman Coulter, USA) flow cytometry. The obtained results were analyzed with KALUZA (Beckman Coulter, USA) program (<FIG>). The expressions of negative markers CD11b, CD19, CD45, CD34 and HLA-DR are <NUM>,<NUM>%; the expression of positive CD105 surface marker is <NUM>,<NUM>%; the expression of CD73 surface marker is <NUM>,<NUM>%; the expression of CD90 surface marker is <NUM>,<NUM>%; the expression of CD44 surface marker is <NUM>,<NUM>%. According to the MSC criteria, negative surface markers must be equal to or less than <NUM>% and positive surface markers must be equal to or higher than <NUM>% in phenotyping. The obtained data meet the criteria.

PRF/MSCs were plated at <NUM> cells/cm<NUM> to <NUM>-well plates to induce adipogenic differentiation at <NUM>. When the cells reached <NUM>-<NUM>% confluency, the culture medium on the cells was aspirated and adipogenic differentiation of cells was induced by enculturation with an "adipogenic differentiation kit" (Gibco, USA) for <NUM> days. Differentiated cells were transformed into adipocytes containing round lipid droplets. Cell differentiation was monitored by staining oil droplets between the cells induced to differentiate adipogenically by AdipoRed Assay Kit (Lonza MD, USA). By staining, adipocytes were observed as pink oil droplets under an inverted microscope (<FIG>).

PRF-MSCs at <NUM>. passage were seeded in <NUM>-well plates at <NUM> cells/cm<NUM> and when the cells reached <NUM>-<NUM>% confluence, the culture medium was replaced with "osteogenic differentiation kit" (Biological Industries, Israel) and osteogenic differentiation of the cells was induced. The cells were induced for two weeks by changing the medium at least twice a week. At the end of two weeks, the calcium depots in the cells were stained with <NUM>% Alizarin Red and the calcium depots in the osteogenically differentiated cells were observed under the inverted microscope by staining (<FIG>).

Claim 1:
Method of obtaining mesenchymal stem cells, comprising the steps of:
• Obtaining Platelet Rich-Fibrin (PRF) by a centrifugation method from blood taken from a venous blood,
• Cutting Platelet rich-fibrin (PRF) tissue into pieces under a laminar flow cabinet,
• Transferring the obtained PRF pieces firstly into D-Lysine coated flasks and adding thereto <NUM>-<NUM>% by volume of human serum, animal serum or <NUM>-<NUM>% by volume of penicillin-streptomycin without serum; <NUM>-<NUM>% by volume of L-glutamine; inorganic salts, such as calcium chloride, potassium chloride, magnesium sulfate, sodium chloride, sodium bicarbonate, sodium phosphate; amino acids, such as L-alanine, L-arginine, L-asparagine-H2O, L-aspartic acid, L-cystine, L-cysteine-HCl-H2O, L-glutamic acid, L-glutamine, glycine, L-histidine, L- isoleucine, L-leucine, L-lysine, L-methionine, L-phenyl alanine, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine; vitamins, such as L-ascorbic acid, biotin, D-Capantothenate, choline chloride, folic acid, i-inositol, niacinamide, pyridoxal HCl, riboflavin, thiamine HCl, vitamin B12; alpha MEM medium containing all of D-glucose lipoic acid, sodium pyruvate, phenol red substances,
• Culturing in an incubator containing <NUM>,<NUM>-<NUM>% by volume of COz at <NUM>,
• Removing of stem cells from the surface to which they were adhered by using <NUM>,<NUM>-<NUM>,<NUM>% by volume of Trypsin-EDTA solution and after <NUM>-<NUM> minutes of centrifugation at <NUM>-<NUM>,
• Obtaining PRF-derived Mesenchymal stem cells (PRF-Derived MSCs).