The contribution of platelets in the production of cryoprecipitates for use in a fibrin glue

A comparison of three-dimensional culture systems to evaluate in vitro chondrogenesis of equine bone marrow-derived mesenchymal stem cells

OBJECTIVE

To compare in vitro three-dimensional (3D) culture systems that model chondrogenesis of bone marrow-derived mesenchymal stem cells (MSCs).

METHODS

MSCs from five horses 2-3 years of age were consolidated in fibrin 0.3% alginate, 1.2% alginate, 2.5×10(5) cell pellets, 5×10(5) cell pellets, and 2% agarose, and maintained in chondrogenic medium with supplemental TGF-β1 for 4 weeks. Pellets and media were tested at days 1, 14, and 28 for gene expression of markers of chondrogenic maturation and hypertrophy (ACAN, COL2B, COL10, SOX9, 18S), and evaluated by histology (hematoxylin and eosin, Toluidine Blue) and immunohistochemistry (collagen type II and X).

RESULTS

alginate, fibrin alginate (FA), and both pellet culture systems resulted in chondrogenic transformation. Adequate RNA was not obtained from agarose cultures at any time point. There was increased COL2B, ACAN, and SOX9 expression on day 14 from both pellet culture systems. On day 28, increased expression of COL2B was maintained in 5×10(5) cell pellets and there was no difference in ACAN and SOX9 between FA and both pellet cultures. COL10 expression was significantly lower in FA cultures on day 28. Collagen type II was abundantly formed in all culture systems except alginate and collagen type X was least in FA hydrogels.

CONCLUSION

equine MSCs respond to 3D culture in FA blended hydrogel and both pellet culture systems with chondrogenic induction. For prevention of terminal differentiation and hypertrophy, FA culture may be superior to pellet culture systems.

Nanotechnology and dental implants

The long-term clinical success of dental implants is related to their early osseointegration. This paper reviews the different steps of the interactions between biological fluids, cells, tissues, and surfaces of implants. Immediately following implantation, implants are in contact with proteins and platelets from blood. The differentiation of mesenchymal stem cells will then condition the peri-implant tissue healing. Direct bone-to-implant contact is desired for a biomechanical anchoring of implants to bone rather than fibrous tissue encapsulation. Surfaces properties such as chemistry and roughness play a determinant role in these biological interactions. Physicochemical features in the nanometer range may ultimately control the adsorption of proteins as well as the adhesion and differentiation of cells. Nanotechnologies are increasingly used for surface modifications of dental implants. Another approach to enhance osseointegration is the application of thin calcium phosphate (CaP) coatings. Bioactive CaP nanocrystals deposited on titanium implants are resorbable and stimulate bone apposition and healing. Future nanometer-controlled surfaces may ultimately direct the nature of peri-implant tissues and improve their clinical success rate.

Fibrin glue in ophthalmology

Suturing is a time consuming task in ophthalmology and suture induced irritation and redness are frequent problems. Postoperative wound infection and corneal graft rejection are examples of possible suture related complications. To prevent these complications, ophthalmic surgeons are switching to sutureless surgery. A number of recent developments have established tissue adhesives like cyanoacrylate glue and fibrin glue as attractive alternatives to sutures. A possible and promising new application for tissue adhesives is to provide a platform for tissue engineering. Currently, tissue glue is being used for conjunctival closure following pterygium and strabismus surgery, forniceal reconstruction surgery, amniotic membrane transplantation, lamellar corneal grafting, closure of corneal perforations and descematoceles, management of conjunctival wound leaks after trabeculectomy, lid surgery, adnexal surgery and as a hemostat to minimise bleeding. The purpose of this review is to discuss the currently available information on fibrin glue.

Preparation of highly concentrated and white cell-poor platelet-rich plasma by plateletpheresis

BACKGROUND AND OBJECTIVES

Contaminating white blood cells (WBC) contribute remarkably to the overall growth factor content of locally applicable platelet-rich plasma (PRP) or platelet (PLT) gel and change the relative proportions of the contained growth factors.

MATERIALS AND METHODS

To study the independent effects of locally applicated highly concentrated PLTs, the development of preparations is needed that contain large amounts of PLTs and no or at least very few leucocytes. Therefore, 20 plateletpheresis procedures were performed in voluntary blood donors to get highly concentrated and extremely WBC-poor plateletpheresis concentrates. The degree of spontaneous PLT activation, the PLT aggregation response to agonists and the level of the growth factor TGF-beta1 (transforming growth factor beta1) were measured immediately after the donation and 1 day later.

RESULTS

The concentrates contained 1.96 +/- 0.36 x 10e11 PLTs per unit in 55.2 +/- 7.9 ml, respectively. In comparison to the donors' blood, the PLT-enrichment factor was 15.3 +/- 5.4. At the same time, the concentrates contained extremely low residual numbers of WBCs (0.8 +/- 3.3 x 10e3/ml). The concentration of the growth factor TGF-beta1 was 743.2 +/- 243.9 ng/ml. On day 1, the PLT concentration and the TGF-beta1 content of the PLT concentrates had not decreased.

CONCLUSIONS

In summary, plateletpheresis is suited to provide PRP products with higher concentrations of human platelets and platelet-derived growth factors than previously reported PRP preparation methods but with extremely low numbers of contaminating leucocytes.