Decellularized kidney matrix for perfused bone engineering.

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.

A novel tool for dynamic cell adhesion studies--the De-Adhesion Number Investigator DANI.

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).

Antimicrobial peptides and proinflammatory cytokines in periprosthetic joint infection.

BACKGROUND: Differentiation between septic and aseptic loosening of joint replacements is essential for successful revision surgery, but reliable markers for the diagnosis of low-grade infection are lacking. The present study was performed to assess intra-articular and systemic levels of antimicrobial peptides and proinflammatory cytokines as diagnostic markers for periprosthetic joint infection. METHODS: Fifteen consecutive patients with staphylococcal periprosthetic joint infections and twenty control patients with aseptic loosening of total hip and knee replacements were included in this prospective, single-center, controlled clinical trial. Expression of the antimicrobial peptides human ß-defensin-2 (HBD-2), human ß-defensin-3 (HBD-3), and cathelicidin LL-37 (LL-37) was determined by ELISA (enzyme-linked immunosorbent assay) in serum and joint aspirates. Proinflammatory cytokines were assessed in serum and joint aspirates with use of cytometric bead arrays. C-reactive protein in serum, microbiology, and histopathology of periprosthetic tissue served as the "gold standard" for the diagnosis of infection. RESULTS: The antimicrobial peptides HBD-3 and LL-37 were significantly elevated in joint aspirates from patients with periprosthetic joint infection compared with patients with aseptic loosening, and the area under the curve (AUC) in a receiver operating characteristic curve analysis was equal to 0.745 and 0.875, respectively. Additionally, significant local increases in the proinflammatory cytokines interleukin (IL)-1ß, IL-4, IL-6, IL-17A, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α were observed to be associated with infection. Logistic regression analysis indicated that the combination of an antimicrobial peptide with another synovial fluid biomarker improved diagnostic accuracy; the AUC value was 0.916 for LL-37 and IL-4, 0.895 for LL-37 and IL-6, 0.972 for HBD-3 and IL-4, and 0.849 for HBD-3 and IL-6. In contrast, the only antimicrobial peptides and cytokines in serum that showed a significant systemic increase in association with infection were HBD-2, IL-4, and IL-6 (all of which had an AUC value of <0.75). CONCLUSIONS: 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.

Surface alterations of polished and sandblasted and acid-etched titanium implants after Er:YAG, carbon dioxide, and diode laser irradiation.

PURPOSE: Laser treatment has become a popular method for resolving peri-implantitis, but the full range of its effects on implant surfaces is unknown. The purpose of the present investigation was to analyze the influence of different clinically applicable erbium:yttrium-aluminum-garnet (Er:YAG), carbon dioxide (CO2), and diode laser parameters on titanium surfaces that were either polished or sandblasted, large-grit, acid-etched (SLA). MATERIALS AND METHODS: Six polished and six SLA titanium disks were irradiated at nine different power settings (n = 54 polished, 54 SLA) with Er:YAG, CO2, or diode lasers. The CO2 and diode lasers were used in continuous wave mode, and the Er:YAG laser was used in a pulsed manner. The surface of each disk was analyzed by scanning electron microscopy and confocal white light microscopy. Each disk was irradiated on six circular areas of 5 mm in diameter with the same specific laser setting for 10 seconds. RESULTS: Within the chosen parameters, the CO2 and diode laser did not cause any visible surface alterations on either the polished or SLA disks. In contrast, both polished and SLA disks showed surface alterations when irradiated with the pulsed Er:YAG laser. The SLA surfaces showed alteration after 10 seconds of irradiation with Er:YAG laser at 300 mJ/10 Hz. The surfaces of the polished disks did not show alteration with the Er:YAG laser until they were irradiated at the higher energy of 500 mJ/10 Hz for 10 seconds. The results of confocal white light microscopy were in agreement with scanning electron micrographs. CONCLUSION: In contrast to continuous-wave diode and CO2 laser irradiation, pulsed Er:YAG laser irradiation caused distinct alterations with power settings beyond 300 mJ/10 Hz on the SLA surface and 500 mJ/10 Hz on the polished surface. Thus, it is only safe to use the Er:YAG laser for implant surface irradiation with settings no higher than 300 or 500 mJ/10 Hz.

Spontaneous in vitro transformation of primary human osteoblast-like cells.

BACKGROUND: Two new tumor-like cell lines were established which developed spontaneously in vitro from normal human primary osteoblast-like cells originating from non-oncogenic bone surgery. MATERIALS AND METHODS: The tumor cell properties studied included morphology, proliferation characteristics in normal and low-serum media, and anchorage-independent growth in soft agarose. RESULTS AND CONCLUSION: Karyotyping of the cells showed numerous rearrangements and abnormalities. These results pointed to the tumorigenic potential of the cells and demonstrate the importance of biosafety in tissue engineering and therapeutic cell applications when prolonged culture conditions are required.

Erbium-doped yttrium aluminium garnet laser-assisted access osteotomy for maxillary sinus elevation: a human and animal cadaver study.

OBJECTIVE: To evaluate the usability of a variable square pulse (VSP) erbium-doped yttrium aluminium garnet (Er:YAG) laser for a lateral access osteotomy to the maxillary sinus in the course of a sinus elevation procedure. MATERIALS AND METHODS: In six formalin-fixed human heads and six fresh sheep heads, a VSP Er:YAG laser was used to perform a bilateral maxillary access osteotomy. For the osteotomies, the Er:YAG laser was applied with a pulse energy of 1000 mJ, a pulse duration of 300 mus, and a frequency of 12 Hz. The spot size was 0.9 mm, and the handpiece was kept approximately 10 mm from the bone surface. RESULTS: In all 24 sites investigated, the Er:YAG laser osteotomy was possible without any visible carbonization or thermal damage. The average time required for laser osteotomy for 12 standardized rectangular lateral windows in human cadavers was 39 s. No anatomical structures limited laser osteotomy, yet a critical evaluation of any membrane perforations was not possible because the postmortem fixation method caused partial detachment and fractional destruction. Laser-access osteotomy in six fresh sheep heads (12 sites) revealed major disruptions and perforations (<8 mm) of the sinus membrane (100%). CONCLUSION: Even though VSP Er:YAG laser osteotomy showed convincing results for efficient bone cutting without thermal damage, applied laser parameters do not seem to be practicable for any clinical sinus elevation procedure. Missing depth control resulted in uncontrollable severe damage of the underlying membrane.

Adult palatum as a novel source of neural crest-related stem cells.

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.

Palatal versus vestibular piezoelectric window osteotomy for maxillary sinus elevation: a comparative clinical study of two surgical techniques.

OBJECTIVES: The goal of this study was to compare the surgical advantages and disadvantages of a new palatal access osteotomy for sinus elevation with a conventional lateral approach. STUDY DESIGN: In 32 patients, either a palatal (n = 16) or a lateral (n = 16) osteotomy to the maxillary sinus was performed under local anesthesia. The palatal access included a circular paramarginal incision and elevation of a palatal mucosal flap based on a median pedicle. The lateral access was performed by vestibular standard incision and development of a mucoperiosteal flap with a vestibular and superior basis. For all osteotomies a piezoelectric device was used. The sinus cavity was augmented with synthetic nanostructured hydroxyapatite graft material. RESULTS: Intraoperative complications during both procedures were minimal and wound healing was uneventful. Membrane perforation occurred in 19% of the palatal group and in 19% of the lateral group. Soft tissue management of the palatal technique was superior to that of the lateral approach, because the vestibular anatomy was not altered and consequently no disharmonious soft tissue scarring and no postoperative swelling occurred. CONCLUSION: The palatal approach permitted higher postoperative comfort, especially for edentulous patients, because full dentures could be incorporated directly after surgery with almost perfect fit.

Oral bacterial cultures in nontraumatic brain abscesses: results of a first-line study.

OBJECTIVE: Bacterial cultures from nontraumatic brain abscesses (BAs) frequently contain oral bacteria. We assessed bacterial cultures from BAs and oral infective sources for a bacterial match. STUDY DESIGN: Bacterial samples from brain abscesses and oral abscesses, and at sites with probing depths >or=3.5 mm were taken from 11 nontraumatic BA patients and analyzed. RESULTS: Brain abscess bacterial cultures were obtained in 9 of the 11 cases, which revealed 5 cases of Streptococcus milleri group bacteria and 4 cases of subgingival flora. The bacteriologic results were interpreted taking all medical and bacteriologic findings into account, which made an oral origin of the BAs most likely in 6 of the 11 cases: from an oral abscess and from the subgingival flora in 3 cases each. CONCLUSIONS: Early collaboration between neurosurgeons, infectious disease specialists, and oral-maxillofacial surgeons will aid the identification and treatment of suspected oral sources of nontraumatic BAs.

A preliminary report about treatment of bisphosphonate related osteonecrosis of the jaw with Er:YAG laser ablation.

BACKGROUND AND OBJECTIVES: This preliminary report describes a new laser-assisted treatment option for the emerging complication of bisphosphonate related osteonecrosis (BON) of the jaw. MATERIALS AND METHODS: In eight tumour patients (three women, five men) ten bony lesions in the maxilla and mandible in the course of intravenous bisphosphonate therapy were treated with a variable square pulsed (VSP) Er:YAG laser. For the treatment, the Er:YAG laser was applied with a pulse energy of 1,000 mJ, a pulse duration of 300 microseconds, and a frequency of 12 Hz (energy density 157 J/cm(2)). The spot size was 0.9 mm and the handpiece was kept at a distance of about 10 mm from the bone surface. The diseased bone was ablated exclusively with the Er:YAG laser by subsequently sweeping the bone surface in a well directed scanning mode. RESULTS: The surgical procedure and postoperative wound healing were without any complications and a complete soft tissue recovering was achieved within 4 weeks. During follow-up examinations over 12 months soft tissue conditions were stable. The pulsed laser ablation caused a characteristic microstructured and craggy bone surface without a condensation or a smear layer on the laser rims. CONCLUSION: The bone ablation technique using a VSP Er:YAG laser yielded promising clinical results without impairment of wound healing. A further analyse of the chemical, physical and pharmacological aspects of laser assisted treatment of BON lesions is necessary to get a safe and reliable treatment protocol for bisphosphonate-related osteonecrosis of the jaw.

[Soft tissue surgery with the diode laser--theoretical and clinical aspects]. / Weichteilchirurgie mit dem Diodenlaser--theoretische und klinische Aspekte.

Currently laser light of different wavelengths is used for all kinds of surgical procedures in oral and maxillofacial surgery. In this regard especially the diode laser is mainly used, because of its excellent effects on oral soft tissues. On the basis of various oral soft tissue lesions in 40 patients the benefits of the diode laser in daily practice are demonstrated. Intraoperative and postoperative clinical findings were excellent due to the sufficient cutting abilities, the good coagulation effect and the extremely small zone of thermal necrosis to surrounding tissues. By this the diode laser has proven as an alternative solution to conventional electrosurgery and scalpel. The precise treatment in the contact application mode, which allowed an easier and more controlled guidance of the laser beam, was another advantage of the fiber-assisted laser system. In conclusion the results show that the diode laser is a useful instrument in oral soft tissue surgery.