Peter Augustín

Effects of activated and nonactivated platelet-rich plasma on proliferation of human osteoblasts in vitro.

PURPOSE The purpose of this study was to evaluate the effect of progressively increasing concentrations of activated and nonactivated platelet-rich plasma (PRP) on proliferation of human osteoblasts in vitro. MATERIALS AND METHODS Human osteoblasts (hFOB 1.19) obtained from the American Type Culture Collection (ATCC, Manassas, VA) were used in the experiment. PRP was obtained from a 28-year-old healthy male volunteer by means of a Haemonetics gradient density cell separator (Haemonetics, Munich, Germany). Human thrombin was used to activate PRP. Three independent experiments were conducted. Samples containing 10% (0.38x increase in platelet count), 25% (0.95x increase in platelet count), 50% (1.95x increase in platelet count), and 75% (2.86x increase in platelet count) of activated PRP and nonactivated PRP were prepared including controls. After culture periods of 24, 48, and 72 hours osteoblast proliferation was evaluated by counting the number of cells using a Multisizer 3 Coulter Counter (Beckman Coulter, Inc, Fullerton, CA). RESULTS After 24, 48, and 72 hours of incubation, the number of cells in the control group (without PRP) was higher than that of cells in samples containing activated or nonactivated PRP. Osteoblasts with 10% activated PRP (0.38x increase in platelet count) had the highest viability of all samples containing PRP. CONCLUSIONS Activated PRP resulted in higher proliferation of osteoblasts compared with nonactivated PRP at concentrations of 10% (0.38x increase in platelet count) and 25% (0.95x increase in platelet count) in culture. This study failed to show significant increases in proliferation of human osteoblasts treated with activated or nonactivated PRP compared with controls in vitro.

Association of Toll-like receptor 9 haplotypes with chronic periodontitis in Czech population.

AIM Toll-like receptors (TLRs) belong to the pattern recognition receptors family of signal molecules that recognize conserved microbial structures. The aim of this study was to analyse polymorphisms in the TLR genes and their association with chronic periodontitis (CP). MATERIAL AND METHODS Two polymorphisms (2408G/A, i.e. Arg753Gln and -16934A/T) in TLR-2 and three variants (-1486C/T, -1237C/T and+2848A/G) in the TLR-9 genes were studied in 222 patients with CP and 259 unrelated controls. All polymorphisms were detected using the polymerase chain reaction-restriction fragment length polymorphism methods. Subgingival bacterial colonization was investigated by the VariOr Dento test. RESULTS No significant differences were found in allele and genotype frequencies of all polymorphisms between patients and controls. Nevertheless, complex analysis revealed differences in TLR9 haplotype frequencies between both groups (p=0.001). Specifically, the haplotype T(-1486)/T(-1237)/A(2848) was significantly more frequent (9.6%versus 2.8%, p<0.000001) and the haplotype T(-1486)/T(-1237)/G (2848) of the TLR9 gene was less frequent (35.9%versus 43.3%, p=0.01) in patients than in controls. However, no significant relationships between periodontal pathogens, TLR polymorphisms and CP were found. CONCLUSIONS In conclusion, although no significant role of the TLR2 gene in periodontitis was found, our results indicate that TLR9 haplotypes may be associated with susceptibility to CP.