Somatic neural and neural crest stem cells are promising sources for cellular therapy of several neurodegenerative diseases. However, because of practical considerations such as inadequate accessibility of the source material, the application of neural crest stem cells is strictly limited. The secondary palate is a highly regenerative and heavily innervated tissue, which develops embryonically under direct contribution of neural crest cells. Here, we describe for the first time the presence of nestin-positive neural crest-related stem cells within Meissner corpuscles and Merkel cell-neurite complexes located in the hard palate of adult Wistar rats. After isolation, palatal neural crest-related stem cells (pNC-SCs) were cultivated in the presence of epidermal growth factor and fibroblast growth factor under serum-free conditions, resulting in large amounts of neurospheres. We used immunocytochemical techniques and reverse transcriptase-polymerase chain reaction to assess the expression profile of pNC-SCs. In addition to the expression of neural crest stem cell markers such as Nestin, Sox2, and p75, we detected the expression of Klf4, Oct4, and c-Myc. pNC-SCs differentiated efficiently into neuronal and glial cells. Finally, we investigated the potential expression of stemness markers within the human palate. We identified expression of stem cell markers nestin and CD133 and the transcription factors needed for reprogramming of somatic cells into pluripotent cells: Sox2, Oct4, Klf4, and c-Myc. These data show that cells isolated from palatal rugae form neurospheres, are highly plastic, and express neural crest stem cell markers. In addition, pNC-SCs may have the ability to differentiate into functional neurons and glial cells, serving as a starting point for therapeutic studies. Stem Cells 2009;27:1899–1910

The present study showed promising results for the use of antimicrobial peptides and other biomarkers in synovial fluid for the diagnosis of periprosthetic joint infection, and analysis of the levels in synovial fluid was more accurate than analysis of serum.

Background: The purpose of this retrospective study was to evaluate the surgical performance, clinical usability and outcome of a new variable square pulsed (VSP) Er:YAG laser for bone cutting in oral and maxillofacial surgery. Materials and Methods: In 40 patients an Er:YAG laser with pulse energy of 1,000 mJ, pulse duration of 300 μs and a frequency of 12 Hz was used for different intraoral osteotomies. The spot size was 0.9 mm, and the handpiece was kept at a distance of 10 mm from the bone surface. Additionally, histological analyses of the fresh osteotomy rims of lasered bone were performed. Results: Er:YAG laser osteotomy revealed a remarkable cutting efficiency without any visible, negative, thermal side effects. There was no damage of adjacent soft tissue structures. However, depth control was limited to visual inspection. Histologically, a 5- to 10-μm-wide zone of a characteristic laser fingerprint appeared on the cut edges. However, there was no sign of thermal tissue damage to the underlying bone structures. Conclusions: VSP Er:YAG laser osteotomy is clinically practicable without any signs of charred tissue and wound healing disturbances. However, the lack of depth control and the necessity for careful handling are still technical limitations to be overcome.

For an optimal implementation of materials, such as, e.g. medical implants in living environments, a thorough characterization of cell adhesion, kinetics and strength is required, as well as a prerequisite e.g. for bone integration. Here we present a miniaturized (~100 μl) lab-on-a-chip implant hybrid system which allows quantification of cell adhesion under dynamic conditions mimicking those of physiological relevance. Surface acoustic waves are excited and used on optical transparent chips to induce micro acoustic streaming and to create a microfluidic shear spectrum ranging from 0 to ~35 s(-1). We demonstrate its potential for a time-efficient, dynamic screening test of new implant materials using a model of an osseointegration with SAOS-2 cells. The upside-down orientation also allows utilization of the micro reactor on non-transparent materials like titanium and diamond-like-carbon (DLC).

Background: In this study the potential of a new and entirely synthetic, nano-structured hydroxyapatite-based biomaterial for sinus floor augmentation is evaluated. Methods: 20 sinus floor elevations were carried out in a total of 20 patients. After a healing period of 6 months, in 10 cases cylinder-shaped bone biopsies were taken from the augmented maxillary region using trephine burs. Results: The healing period progressed without any complications. General and specific histological analysis of the bone biopsies showed a high osteoclast activity at the margin of the biomaterial which was well integrated into the newly formed bone. Conclusion: This study demonstrates that new trabecular bone is formed after grafting with the nanocrystalline bone substitute after 6 months. Ongoing histomorphological studies are necessary to quantify the biomaterial-bone ratio and the exact amount of newly built bone in the augmented cavity after 6 months.

BackgroundThe idea of tissue decellularization to gain matrices for tissue engineering is promising. The aim of the present study is to establish a safe and reproducible protocol for solid tissue decellularization that prevents the architecture of the matrix with the inherent vascular network.MethodsThe study was performed in rat kidneys which were decellularized by a SDS-based perfusion protocol. Perfusion time and SDS concentration were systematically changed to obtain the shortest and most gentle protocol that leads to complete decellularization.ResultsWe investigated kinetics of protein elution, decellularization success, and remaining cell toxicity. This resulted in a reproducible protocol, leading to safe decellularization with prevention of the inherent vascular network, without remaining detectable cell toxicity. The established protocol leads to solid tissue decellularization in only 7 h, which is by far shorter than the previously published methods.ConclusionThe established technique has the potential to become a relevant platform technology for tissue engineering of solid tissues. It provides a solution for the yet-unsolved problem of vascularization.

The vascularization of tissue-engineered constructs is yet an unsolved problem. Here, recent work on the decellularization of whole organs has opened new perspectives on tissue engineering. However, existing decellularization protocols last several days and derived biomatrices have only been reseeded with cells from the same tissue origin or stem cells differentiating into these types of tissue. Within the present work, we demonstrate a novel standardized, time-efficient, and reproducible protocol for the decellularization of solid tissues to derive a ready to use biomatrix within only 5 h. Furthermore, we prove that biomatrices are usable as potential scaffolds for tissue engineering of vascularized tissues, even beyond tissue and maybe even species barriers. To prove this, we seeded human primary osteoblasts into a rat kidney bioscaffold. Here, seeded cells spread homogeneously within the matrix and proliferate under dynamic culture conditions. The cells do not only maintain their original phenotype within the matrix, they also show a strong metabolic activity and remodel the biomatrix toward a bone-like extracellular matrix. Thus, the decellularization technique has the ability to become a platform technology for tissue engineering. It potentially offers a universally applicable and easily producible scaffold that addresses the yet unsolved problem of vascularization.

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