First Clinical Application of Polyurethane Meniscal Scaffolds with Mesenchymal Stem Cells and Assessment of Cartilage Quality with T2 Mapping at 12 Months.

BACKGROUND: Complex meniscal lesions often require meniscectomy with favorable results in the short term but a high risk of early osteoarthritis subsequently. Partial meniscectomy treated with meniscal substitutes may delay articular cartilage degeneration. PURPOSE: To evaluate the status of articular cartilage by T2 mapping after meniscal substitution with polyurethane scaffolds enriched with mesenchymal stem cells (MSC) and comparison with acellular scaffolds at 12 months. METHODS: Seventeen patients (18-50 years) with past meniscectomies were enrolled in 2 groups: (1) acellular polyurethane scaffold (APS) or (2) polyurethane scaffold enriched with MSC (MPS). Patients in the MPS group received filgrastim to stimulate MSC production, and CD90+ cells were obtained and cultured in the polyurethane scaffold. The scaffolds were implanted arthroscopically into partial meniscus defects. Concomitant injuries (articular cartilage lesions or cartilage lesions) were treated during the same procedure. Changes in the quality of articular cartilage were evaluated with T2 mapping in femur and tibia at 12 months. RESULTS: In tibial T2 mapping, values for the MPS group increased slightly at 9 months but returned to initial values at 12 months (P > 0.05). In the APS group, a clear decrease from 3 months to 12 months was observed (P > 0.05). This difference tended to be significantly lower in the APS group compared with the MPS group at the final time point (P = 0.18). In the femur, a slight increase in the MPS group (47.8 ± 3.4) compared with the APS group (45.3 ± 4.9) was observed (P > 0.05). CONCLUSION: Meniscal substitution with polyurethane scaffold maintains normal T2 mapping values in adjacent cartilage at 12 months. The addition of MSC did not show any advantage in the protection of articular cartilage over acellular scaffolds (P > 0.05).

The enzymatic poly(gallic acid) reduces pro-inflammatory cytokines in vitro, a potential application in inflammatory diseases.

Cytokines like IL-6, TNF-α, and IL-1ß are important mediators of inflammation in many inflammatory diseases, as well as in cellular processes like cell proliferation and cell adhesion. Finding new molecules that decrease cell proliferation, adhesion (inflammatory infiltrate), and pro-inflammatory cytokine release could help in the treatment of many inflammatory diseases. The naturally derived poly(gallic acid) (PGAL), produced enzymatically from gallic acid in aqueous medium, is a non-toxic, thermostable multiradical polyanion that is antioxidant and has potential biomedical uses. Experimental evidence has demonstrated that PGAL reduces pro-inflammatory cytokines, which are the target of some inflammatory diseases. PGAL decreased IL-6, TNF-α, and IL-1ß production in human monocytes exposed to PMA without affecting cell viability. Additionally, PGAL reduced cell proliferation by affecting the transition from the S phase to the G2 phase of the cell cycle. Cell adhesion experiments showed that PMA-induced cell adhesion was diminished with the presence of PGAL, particularly at a concentration of 200 µg/mL. These properties of PGAL show a potential use for treating inflammatory diseases, such as psoriasis or arthritis.

Sterilized chitosan-based composite hydrogels: Physicochemical characterization and in vitro cytotoxicity.

Gelatin/chitosan/polyvinyl alcohol hydrogels were fabricated at different polymer ratios using the freeze-drying and sterilized by steam sterilization. The thermal stability, chemical structure, morphology, surface area, mechanical properties, and biocompatibility of hydrogels were evaluated by simultaneous thermal analysis, Fourier transform infrared spectroscopy, X-ray diffraction, confocal microscopy, adsorption/desorption of nitrogen, rheometry, and 3-4,[5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide cell viability assay (MTT assay), respectively. The samples showed a decomposition onset temperature below 253.3 ± 4.8°C, a semicrystalline nature, and a highly porous structure. Hydrogels reached the maximum water uptake in phosphate-buffered saline after 80 min, showing values from nine to twelve times their dry mass. Also, hydrogels exhibiting a solid-like behavior ranging from 2,567 ± 467 to 48,705 ± 2,453 Pa at 0.1 rad/s (low frequency). The sterilized hydrogels showed low cytotoxicity (cell viability > 70%) to the HT29-MTX-E12 cell line. Sterilized hydrogels by steam sterilization can be good candidates as scaffolds for tissue engineering applications.

Co-culture of dedifferentiated and primary human chondrocytes obtained from cadaveric donor enhance the histological quality of repair tissue: an in-vivo animal study.

To compare the quality of the repair tissue in three-dimensional co-culture of human chondrocytes implanted in an in vivo model. Six cadaveric and five live human donors were included. Osteochondral biopsies from the donor knees were harvested for chondrocyte isolation. Fifty percent of cadaveric chondrocytes were expanded until passage-2 (P2) while the remaining cells were cryopreserved in passage-0 (P0). Fresh primary chondrocytes (P0f) obtained from live human donors were co-cultured. Three-dimensional constructs were prepared with a monolayer of passage-2 chondrocytes, collagen membrane (Geistlich Bio-Gide®), and pellet of non-co-cultured (P2) or co-cultured chondrocytes (P2 + P0c, P2 + P0f). Constructs were implanted in the subcutaneous tissue of athymic mice and left for 3 months growth. Safranin-O and Alcian blue staining were used to glycosaminoglycan content assessment. Aggrecan and type-II collagen were evaluated by immunohistochemistry. New-formed tissue quality was evaluated with an adaptation of the modified O'Driscoll score. Histological quality of non-co-cultured group was 4.37 (SD ±4.71), while co-cultured groups had a mean score of 8.71 (SD ±3.98) for the fresh primary chondrocytes and 9.57 (SD ±1.27) in the cryopreserved chondrocytes. In immunohistochemistry, Co-culture groups were strongly stained for type-II and aggrecan not seen in the non-co-cultured group. It is possible to isolate viable chondrocytes from cadaveric human donors in samples processed in the first 48-h of dead. There is non-significant difference between the numbers of chondrocytes isolated from live or cadaveric donors. Cryopreservation of cadaveric primary chondrocytes does not alter the capability to form cartilage like tissue. Co-culture of primary and passaged chondrocytes enhances the histological quality of new-formed tissue compared to non-co-cultured cells.

Generation of Two Biological Wound Dressings as a Potential Delivery System of Human Adipose-Derived Mesenchymal Stem Cells.

Human adipose-derived mesenchymal stem cells (hADMSCs) are believed to be potential key factors for starting the regenerative process after tissue injury. However, an efficient method of delivering these regenerative cells to an external wound site is still lacking. Human amnion and pig skin have long been used as skin wound dressings for the treatment of burns and other skin lesions. Herein, we present the generation of two constructs using these two biomaterials as effective scaffolds for the culture of hADMSCs. It was found that hADMSCs seeded onto radiosterilized human amnion and pig skin are viable and proliferate. These cells are able to migrate over these scaffolds as demonstrated by using time-lapse microscopy. In addition, the scaffolds induce hADMSCs to secrete interleukin-10, an important negative regulator of inflammation, and interleukin-1ß, a proinflammatory protein. The interplay between these two proteins has been proven to be vital for a balanced restoration of all necessary tissues. Thus, radiosterilized human amnion and pig skin are likely suitable scaffolds for delivery of hADMSCs transplants that could promote tissue regeneration in skin injuries like patients with burn injuries.

Lesión de médula espinal y medicina regenerativa: [revisión] / Spinal cord injury and regenerative medicine: [review]

La lesión medular (LM) es un problema que afecta sobre todo a la población en edad laboral y, por lo tanto, sus repercusiones rebasan el ámbito familiar. La LM es irreversible para la mitad de las víctimas y en la actualidad los tratamientos existentes consisten en la asistencia y la estabilización espinal. Con el reconocimiento de la existencia de células madre (CM), el tratamiento de la LM ha recibido otro enfoque. Las CM se encargan de la renovación de los tejidos durante la vida del individuo y su reparación en caso de lesión. Las CM más atractivas desde el punto de vista terapéutico son las capaces de generar diversos tejidos, obtenibles con facilidad, y cuya manipulación es aceptable en términos éticos. En este artículo se presentan algunos de los estudios realizados con CM de diversos orígenes y su aplicación al tratamiento de la LM.

Spinal cord injury (SCI) is a trauma problem striking mainly working age adults, therefore affecting society beyond the victim’s family circle. Most of the victims of SCI will never recover; therapy for this type of injury consists basically on spinal cord support and stabilization. With the discovery of stem cells (SC), SCI treatment has been given another chance. Stem cells are responsible for tissue renewal throughout the individual’s life, as well as tissue repair when needed. From the therapeutic point of view, the most appealing SC are those capable of generating a variety of tissues, those easily harvested, and finally, those ethically unquestioned. This article summarizes some studies carried with SC of various origins and their application to SCI treatment.

[Results of the experimental repair of osteochondral lesions in a pig model using tissue engineering]. / Resultados en la reparación experimental de lesiones osteocondrales en un modelo porcino mediante ingeniería de tejidos.

OBJECTIVE: To repair experimental osteochondral knee lesions in pigs using tissue engineering. MATERIAL AND METHODS: Eight 40-kg pigs underwent surgery. Cartilage and periosteal biopsies of their control knee were taken. Cartilage and periosteal cells were independently isolated, cultured and seeded in biodegradable PGA and PLA polymers that were fixed on the bottom of an osteochondral defect in the pig's experimental knee, with bioabsorbable Mitek implants. Four months later the pigs were sacrificed and the knees were analyzed with nuclear magnetic resonance imaging (NMRI), macroscopic assessment, histology, electron microscopy (EM), scanning electron microscopy (SEM) and SEM element analysis. RESULTS: All the defects were filled with cartilage-like tissue according to the NMRI evaluation and the visual examination. Hyaline-like cartilage was obtained in 3 defects and fibrocartilage in 5. The EM showed chondrocytes in the repair tissue. The SEM showed appropriate integration to the bone and the surrounding tissue. SEM element analysis showed sulphurized matrix attached to the bone with calcium and phosphates as predominant elements. DISCUSSION: Tissue engineering enabled the production of tissues similar to normal ones. The polymer fixation system was effective.

[Spinal cord injury and regenerative medicine]. / Lesión de médula espinal y medicina regenerativa.

Spinal cord injury (SCI) is a trauma problem striking mainly working age adults, therefore affecting society beyond the victims family circle. Most of the victims of SCI will never recover; therapy for this type of injury consists basically on spinal cord support and stabilization. With the discovery of stem cells (SC), SCI treatment has been given another chance. Stem cells are responsible for tissue renewal throughout the individuals life, as well as tissue repair when needed. From the therapeutic point of view, the most appealing SC are those capable of generating a variety of tissues, those easily harvested, and finally, those ethically unquestioned. This article summarizes some studies carried with SC of various origins and their application to SCI treatment.