Efficacy of biocompatible trilayers nanofibrous scaffold with/without allogeneic adipose-derived stem cells on class II furcation defects of dogs' model.

OBJECTIVE: This study aimed to evaluate the regenerative capacity of a newly-developed polycaprolactone (PCL)-based nanofibrous composite scaffold either alone or in combination with adipose-derived mesenchymal stem cells (ADSCs) as a treatment modality for class II furcation defects. MATERIALS AND METHODS: After ADSCs isolation and scaffold characterization, the mandibular premolars of adult male mongrel dogs were selected and randomly assigned into three equal groups. In group I, class II furcation defects were surgically induced to the inter-radicular bone. While class II furcation defects of group II were induced as in group I. In addition, the defects were filled with the prefabricated scaffold. Moreover, class II furcation defects of group III were induced as in group II and instead the defects were filled with the prefabricated scaffold seeded with ADSCs. The dogs were sacrificed at 30 days or at 60 days. Periodontal wound healing/regeneration was evaluated by radiological examination using cone beam computed tomography and histologically using ordinary, histochemical, and immunohistochemical staining. RESULTS: In the two examination periods, group II defects compared to group I, and group III compared to the other groups showed a decrease in defect dimensions radiographically. Histologically, histochemically, and immunohistochemically, they significantly demonstrated better periodontal wound healing/regeneration, predominant collagen type I of newly formed bone and periodontal ligament with a significant increase in the immunoreactivity of vascular endothelial growth factor and osteopontin. CONCLUSIONS: The newly fabricated nanofibrous scaffold has enhanced periodontal wound healing/regeneration of class II furcation defects with further enhancement achieved when ADSCs seeded onto the scaffold before implantation. CLINICAL RELEVANCE: The implementation of our newly-developed PCL-based nanofibrous composite scaffolds in class II furcation defect either alone or in conjunction with ADSCs can be considered as a suitable treatment modality to allow periodontal tissues regeneration.

Enhanced Osteogenic Differentiation of Pluripotent Stem Cells via γ-Secretase Inhibition.

Bone healing is a complex, well-organized process. Multiple factors regulate this process, including growth factors, hormones, cytokines, mechanical stimulation, and aging. One of the most important signaling pathways that affect bone healing is the Notch signaling pathway. It has a significant role in controlling the differentiation of bone mesenchymal stem cells and forming new bone. Interventions to enhance the healing of critical-sized bone defects are of great importance, and stem cell transplantations are eminent candidates for treating such defects. Understanding how Notch signaling impacts pluripotent stem cell differentiation can significantly enhance osteogenesis and improve the overall healing process upon transplantation. In Rancourt's lab, mouse embryonic stem cells (ESC) have been successfully differentiated to the osteogenic cell lineage. This study investigates the role of Notch signaling inhibition in the osteogenic differentiation of mouse embryonic and induced pluripotent stem cells (iPS). Our data showed that Notch inhibition greatly enhanced the differentiation of both mouse embryonic and induced pluripotent stem cells.

Scanning electron microscopy observations of osseointegration failures of dental implants that support mandibular overdentures.

AIM: : Investigating possible failure causes of mandibular implants after their immediate loading with an overdenture retained with bilateral bar attachments, using scanning electron microscope. PATIENTS AND METHODS: Twenty edentulous male patients were included in the present study. Each patient had 2 fixtures inserted in the canine and the first molar areas on each side of the mandible. After abutments screwing, the 2 fixtures on the same side were splinted with a bar, and immediately loaded with an overdenture. Implants mobility was assessed on weekly basis. Failed implants were removed, and examined by scanning electron microscope. RESULTS: The failed implants, removed after 4 weeks of treatment, showed an intimate contact of mineralized and osteoid tissues with dense collagen-rich matrix in the apical third of implants. Furthermore, newly developed bone was observed at the same area in implants removed after 7 weeks. However, there was no evidence of such growth at the middle and/or cervical thirds in either case. CONCLUSION: Lack of osseointegration at the middle and cervical thirds of the root could be a possible cause of implant failure. Early loading by an overdenture retained with bilateral bars is considered a major contributing factor to incomplete osseointegration of the supporting implants.

Solution microstructures of the micellar phase of Pluronic L64/SDS/water system.

Here we report on a study dealing with a self-assembling ethylene oxide-propylene oxide-ethylene oxide triblock copolymer (Pluronic L64) and an anionic surfactant, sodium dodecyl sulfate (SDS), that in water at 25 degrees C form an interesting micellar region (L-phase). We have investigated the sequence of micelle structures in this L-phase across a wide interval of copolymer concentrations using phase diagram determination, steady shear, and NMR self-diffusion (pulsed gradient spin-echo, PGSE) experiments. In solutions which have been prepared at moderately low copolymer concentrations (ca. 20wt.% L64) we report on a transition from discrete micelles to bicontinuous aggregates on the addition of SDS. This change was mainly inferred from self-diffusion coefficient patterns (i.e., the variation of copolymers and surfactant diffusivity vs. SDS content). At midrange and at higher polymer concentrations (i.e., in the interval from 50 to 80wt.% L64) the L-phase occurred with a bicontinuous structure which was not modified by the progressive addition of SDS. Such a bicontinuous structure was identified by the comparison of self-diffusion coefficients of both cosolutes and the bulk viscosity (i.e., the behavior of zero-shear viscosity vs. SDS).

Current aspects of blastocyst cryopreservation.

Cryopreservation of human gametes and embryos has become an essential part of assisted reproduction. Successful cryopreservation of human blastocysts is increasingly relevant as extended in-vitro culture of human embryos becomes more common, permitting routine use of blastocyst transfer in IVF programmes. This reduces the number of embryos transferred, thereby reducing multiple pregnancies and maximizing cumulative pregnancy rates per oocyte retrieval. The superiority of blastocyst freezing over earlier stage freezing in terms of implantation per thawed embryo transferred improves overall expectations for the cryopreservation programme. Therefore, a reliable procedure for the cryopreservation of blastocysts is needed because, after transfer, only a small number of supernumerary blastocysts are likely to be available for cryopreservation. Since the early 1980s, two common techniques have been used in cryopreservation: the conventional slow cooling method and the more recent rapid procedure known as vitrification. Vitrification has become an attractive alternative to slow freezing, since it appears to result in significantly higher survival and pregnancy rates. The aim of this review is to focus on the cryopreservation of human blastocysts using slow and rapid protocols and to assess the impact of the crypreservation protocol used on the survival, implantation and pregnancy rates.

DNA damage of human spermatozoa in assisted reproduction: origins, diagnosis, impacts and safety.

Sperm DNA contributes half the offspring's genomic material and abnormal DNA can lead to derangements in the reproductive process. Normal sperm genetic material is required for successful fertilization, as well as for further embryo and fetal development that will result in a healthy child. Thus, the damage to sperm DNA is critical in assisted reproductive techniques which are increasingly used to treat infertile couples. There has been improving data about the effects of human sperm DNA damage or fragmentation. As well, increasing knowledge concerning the effects of DNA damage on embryo and fetal development has been attained. This review aims to summarize the present knowledge on the impact of human sperm cell DNA damage on male infertility and outcome in the context of safety.