Regenerative and hepatospecific activity of total RNA from xenogenic bone marrow cells

Objective: to study the peculiarities of the induction effect of total RNA (tRNA) from xenogenic bone marrow cells (BMCs) on regeneration processes in the recipient's native liver with extensive liver resection using an adoptive transfer model. Materials and methods. The study was carried out on an adoptive transfer model using male Wistar rats (n = 20) and guinea pigs (n = 17). The donors were rats (n = 10). 12 hours after extensive liver resection (70-75%), tRNA was isolated from BMCs and injected into intact (non-operated) recipients intraperitoneally at a dose of 30 μg/100 g of weight. The induction effect of the tRNA on operated rats was studied in 3 groups of recipients: Group 1 (control, n = 5) - administration of saline to guinea pigs; Group 2 (control, n = 10) - administration of tRNA from a donor rat to a recipient rat (allogeneic transfer); Group 3 (experiment, n = 12) - administration of tRNA from a donor rat to a recipient guinea pig (xenogeneic transfer). In histological preparations of recipient livers, after 48, 72 hours and 7 days, we studied the mitotic activity of hepatocytes and the features of the microscopic picture of the liver. The significance of differences in the compared groups was assessed using the parametric Student's t-test. Results. The ability of BMC tRNA to tissue-specifically activate regenerative and immune responses in the liver after extensive resection was found to depend on the donor and recipient species identity. Introduction of allogeneic donor tRNA in the recipient's liver resulted in predominant enhancement in hepatocyte mitotic activity (p < 0.05). The use of xenogeneic donor tRNA leads to enhanced activity of only immuno-inflammatory reactions in the recipient's liver, such as sinusoidal cell activation, lymphocytic infiltration into sinusoids, and portal tract infiltration by inflammatory cells. Conclusion. To induce regenerative processes in the liver, tRNA obtained from allogeneic BMCs should be used.

Comparison of the crestal bone loss between implant-supported prosthesis with sinus augmentation and distal cantilevered implant-supported prosthesis without sinus augmentation

This study aimed to compare the crestal bone loss between a two implant-supported, non-cantilevered three-unit fixed partial prosthesis (TUFPP) with sinus augmentation and a two implant-supported, distal cantilevered TUFPP without sinus augmentation in the posterior maxilla having insufficient crestal bone. The study subjects were enrolled into two groups. Group 1 included patients with two implants, an anterior implant placed in the native bone and a posterior implant inserted with simultaneous sinus augmentation using a xenogenic bone graft to support a TUFPP, and group 2 included patients with two implants inserted in the native bone to support a distal cantilevered TUFPP. The crestal bone levels at the distal and mesial aspects of each implant were measured at baseline and 6-, 12-, and 24-month follow-up controls on panoramic radiographs. Fifty-two patients and 104 implants were included. There was a significant difference in distal crestal bone loss between anterior and posterior implants in group 1 at 6 months (p&lt;0.05), but not at 12 and 24 months (p&gt;0.05). Distal crestal bone loss was significantly increased in group 1 posterior implants compared to the group 2 posterior implants at 6 months (p&lt;0.05). There was no significant difference in mesial bone loss between the anterior and posterior implants in both groups at all follow-up controls (p&gt;0.05). There was also no significant mesial crestal bone loss in relation to the anterior and posterior implants of both groups at all follow-up controls (p&gt;0.05). Non-cantilevered two implant-supported TUFPP with sinus augmentation may have similar medium term crestal bone loss when compared to cantilevered two implant-supported TUFPP without sinus augmentation. Further prospective studies should be designed to compare the performance of the two implant-supported cantilevered TUFPP and two implant-supported TUFPP with sinus augmentation.

A Comprehensive Microstructural and Compositional Characterization of Allogenic and Xenogenic Bone: Application to Bone Grafts and Nanostructured Biomimetic Coatings

Bone grafts and bone-based materials are widely used in orthopedic surgery. However, the selection of the bone type to be used is more focused on the biological properties of bone sources than physico-chemical ones. Moreover, although biogenic sources are increasingly used for deposition of biomimetic nanostructured coatings, the influence of specific precursors used on coating’s morphology and composition has not yet been explored. Therefore, in order to fill this gap, we provided a detailed characterization of the properties of the mineral phase of the most used bone sources for allografts, xenografts and coating deposition protocols, not currently available. To this aim, several bone apatite precursors are compared in terms of composition and morphology. Significant differences are assessed for the magnesium content between female and male human donors, and in terms of Ca/P ratio, magnesium content and carbonate substitution between human bone and different animal bone sources. Prospectively, based on these data, bone from different sources can be used to obtain bone grafts having slightly different properties, depending on the clinical need. Likewise, the suitability of coating-based biomimetic films for specific clinical musculoskeletal application may depend on the type of apatite precursor used, being differently able to tune surface morphology and nanostructuration, as shown in the proof of concepts of thin film manufacturing here presented.

Combination of an allogenic and a xenogenic bone substitute material with injectable platelet-rich fibrin – A comparative in vitro study

The aim of the in vitro study was a comparison of an allogenic (ABSM) and a xenogenic bone substitute material (XBSM) with and without injectable platelet-rich fibrin (ABSM-i-PRF & XBSM-i-PRF) on cell characteristics of human osteoblasts (HOB). Here, ABSM and XBSM (+ i-PRF = test; - i-PRF = control) were incubated with HOB for 3, 7 and 10 days. HOB viability, migration, proliferation and differentiation (RT-PCR on alkaline phosphatase (AP), bone morphogenetic protein 2 (BMP-2) and osteonectin (OCN)) were measured and compared between groups. At day 3, an increased viability, migration and proliferation was seen for ABSM-i-PRF. For viability and proliferation (days 7 and 10) and for migration (day 10), ABSM-i-PRF/XBSM-i-PRF showed higher values compared to ABSM/XBSM with maximum values for ABSM-i-PRF and minimum values for XBSM. At days 3 and 7, the highest expression of AP was detected in ABSM-i-PRF/XBSM-i-PRF when compared to ABSM/XBSM, whereas at day 10, AP expression levels were elevated in ABSM-i-PRF/ABSM. The highest BMP-2 expression was seen in ABSM-i-PRF whereas OCN expression showed higher levels in ABSM-i-PRF/XBSM-i-PRF at days 3 and 7 with lowest expression for ABSM. Later on, elevated OC levels were detected for ABSM-i-PRF only. In conclusion, i-PRF in combination with ABSM enhances HOB activity when compared to XBSM-i-PRF or untreated BSM in vitro. Therefore, addition of i-PRF to ABSM and – to a lower extent – to XBSM may influence osteoblast activity in vivo.

Immediate implant placement in anterior teeth with grafting material of autogenous tooth bone vs xenogenic bone

Background The aim of the study was to compare the efficacy of the autogenous tooth bone and xenogenic bone grafted in immediate implant placement with bone defect. Methods Thirty patients whose compromised anterior teeth need immediate implant placement were enrolled. Autogenous tooth bone made from the extracted teeth by chair-side or the xenogenic bone were used to repaired bone defect. Clinical examination, radiographic assessment about the horizontal bone change in the level of 0 mm, 3 mm and 6 mm below the implant neck and the marginal bone loss were made immediately, 6 and 12 months after implant placement. Questionnaire of the feelings about the surgery were made at the time of removing the sutures. Results All implants achieved the success criteria without any complications at the follow-up period. The percent of the horizontal bone change and the marginal bone loss at 6 and 12 months were almost the same between two groups (P > .05). The horizontal bone loss at the first or the latter 6 months was almost the same (P > .05). But the horizontal bone loss at the 6 mm level was less than the 0 mm and 3 mm levels at 6 and 12 months (P < .05). Meanwhile patients seem more satisfied with the autogenous tooth bone derived from the questionnaire. Conclusion The bone volume change in the facial part of the implant after immediate placement is almost the same between two groups. Providing clinical evidence that the autogenous tooth bone made from compromised tooth can be an acceptable bone graft material.

Immediate implant placement in anterior teeth with grafting material of autogenous tooth bone vs xenogenic bone

Background: The aim of the study was to compare the efficacy of the autogenous tooth bone and xenogenic bone grafted in immediate implant placement with bone defect. Methods: Thirty patients whose compromised anterior teeth need immediate implant placement were enrolled. Autogenous tooth bone made from the extracted teeth by chair-side or the xenogenic bone were used to repaired bone defect. Clinical examination, radiographic assessment about the horizontal bone change in the level of 0mm, 3mm and 6mm below the implant neck and the marginal bone loss were made immediately, 6 and 12 months after implant placement. Questionnaire of the feelings about the surgery were made at the time of removing the sutures. Results: All implants achieved the success criteria without any complications at the follow-up period. The percent of the horizontal bone change and the marginal bone loss at 6 and 12 months were almost the same between two groups (P>.05). The horizontal bone loss at the first or the latter 6 months was almost the same (P>.05). But the horizontal bone loss at the 6 mm level was less than the 0 mm and 3 mm levels at 6 and 12 months (P<.05). Meanwhile patients seem more satisfied with the autogenous tooth bone derived from the questionnaire. Conclusion: The bone volume change in the facial part of the implant after immediate placement is almost the same between two groups. Providing clinical evidence that the autogenous tooth bone made from compromised tooth can be an acceptable bone graft material.