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Background This study investigates the relationship between Edmonton Obesity Staging System (EOSS) and the occurrence of postoperative complications after abdominoplasty in massive weight loss patients. Methods A single-institution retrospective review of patients undergoing abdominoplasty between 2009 and 2019 after massive weight loss. Demographic data, laboratory findings, known risk factors for postoperative complications, as well as data on major and minor complications were extracted from the patient charts. Logistic regression models were used to investigate the relationship between the variables. Results Four hundred and five patients were included in the study. The prevalence of EOSS stages was: 0 (no comorbidities, N = 151, 37%), 1 (mild conditions, N = 40, 10%), 2 (moderate conditions, N = 149, 36%) and 3 (severe conditions, N = 70, 17%). Regression analysis showed that, controlling for body mass index (BMI), BMI Δ (maximal BMI - BMI at presentation), bariatric surgery, volume of resected tissue, and duration of surgery, EOSS stage significantly associated with the occurrence of postoperative complications. Compared with EOSS stage 0, EOSS stages 2 and 3 patients were associated with significantly more minor and major complications, respectively. The volume of resected tissue, BMI Δ, and age were associated with the occurrence of major complications. A regression model of comorbidities comprising the EOSS revealed a significant association of variables diabetes mellitus and hypertension with the occurrence of postoperative complications. Conclusions Edmonton Obesity Staging System is a robust predictor of postoperative complications in abdominoplasty.

Mesenchymal stem cells (MSCs) represent a very important cell source in the field of regenerative medicine and for bone and cartilage tissue engineering applications. Three-dimensional (3D) bioprinting has the potential to improve the classical tissue engineering concept as this technique allows the printing of cells with high spatial control of cell allocation within a 3D construct. In this study, we systematically compared different hydrogel blends for 3D bioprinting of MSCs by testing their cytocompatibility, ability to support osteogenic differentiation and their mechanical properties. In addition, we compared four different MSC populations isolated from different human tissues for their osteogenic differentiation capacity in combination with different hydrogels. The aim of this study was to identify the best MSC source and the most suitable hydrogel blend for extrusion-based bioprinting of 3D large-scaled osteogenic constructs. MSCs were isolated from different tissues (umbilical cord, adipose tissue, bone marrow). MSCs were seed onto or into different hydrogels and analyzed for cell viability, proliferation and osteogenic differentiation. In addition, viscoelastic properties of the hydrogels were determined. MSC-containing cubes with the size of 1 cm3 were printed by means of 3D extrusion-based bioprinting and analyzed by (immuno)histology for cell survival and production of a calcified extracellular matrix. Adipose tissue derived MSCs (ASCs) showed the highest osteogenic differentiation potential. A complex hydrogel blend consisting of fibrin, gelatin, hyaluronic acid, glycerol (F/G/H/Gl), tuned with hydroxyapatite, showed the best viscoelastic properties in combination with an excellent biocompatibility towards ASCs. This cell/hydrogel combination was used to bioprint 3D cubes. The cubes showed good mechanical stability and the printed ASCs were viable and able to calcify the hydrogel after bioprinting. The combination of the HA-tuned F/G/H/Gl hydrogel blend along with ASCs can be considered as a very promising bioink for 3D bioprinting of artificial bone tissue equivalents for prospective applications in tissue engineering and regenerative medicine.

Background: In the genetic skin blistering disorder dystrophic epidermolysis bullosa recurrent blisters and erosions on mechanically stressed areas, as the hands, result in subsequent scarring and development of pseudosyndactylies and contractures. In its most severe form, all fingers are constrained into a fist of scarred (“mitten-hand”-deformity). No causative therapy exists and only a surgical release of the fingers is possible. Hereby, the development of large skin defects is inevitable; the lack of healthy autologous skin for grafting remains a difficult challenge.Methods: We propose a new technique: It adopts a treatment strategy from the therapy of large extent burns and consists of a combination of autogenic and allogenic skin grafting.Results: We present a beneficial outcome in 18 mitten hand deformities treated with this technique. In all patients, the initial functional outcome was improved. Nearly all patients got a considerably widened grip span and durable skin conditions post-operatively. Mean follow-up was 3 years. Typically, recurrence of the scarring occurred from 6 months to 2 years after operation.Conclusions: This is the first report on the use of the combination of autogenous pinch skin grafts with allogenic (parental) skin overlay for skin defects in EB. It provides undisturbed wound healing under a “biological dressing”, furthermore, a temporary take of the parental skin was visible. Defects were permanently covered with skin of increased mechanical stability, hand function improved remarkably. However, long term follow-up showed beginning recurrence in most of the patients comparable to recurrence rates described in the literature.

The homogeneity of the genetically modified single-cells is a necessity for many applications such as cell line development, gene therapy, and tissue engineering and in particular for regenerative medical applications. The lack of tools to effectively isolate and characterize CRISPR/Cas9 engineered cells is considered as a significant bottleneck in these applications. Especially the incompatibility of protein detection technologies to confirm protein expression changes without a preconditional large-scale clonal expansion, creates a gridlock in many applications. To ameliorate the characterization of engineered cells, we propose an improved workflow, including single-cell printing/isolation technology based on fluorescent properties with high yield, a genomic edit screen (surveyor assay), mRNA rtPCR assessing altered gene expression and a versatile protein detection tool called emulsion-coupling to deliver a high-content, unified single-cell workflow. The workflow was exemplified by engineering and functionally validating RANKL knockout immortalized mesenchymal stem cells showing altered bone formation capacity of these cells. The resulting workflow is economical, without the requirement of large-scale clonal expansions of the cells with overall cloning efficiency above 30% of CRISPR/Cas9 edited cells. Nevertheless, as the single-cell clones are comprehensively characterized at an early, highly parallel phase of the development of cells including DNA, RNA, and protein levels, the workflow delivers a higher number of successfully edited cells for further characterization, lowering the chance of late failures in the development process.Author summaryI completed my undergraduate degree in biochemistry at the University of Ulm and finished my master's degree in pharmaceutical biotechnology at the University of Ulm and University of applied science of Biberach with a focus on biotechnology, toxicology and molecular biology. For my master thesis, I went to the University of Freiburg to the department of microsystems engineering, where I developed a novel workflow for cell line development. I stayed at the institute for my doctorate, but changed my scientific focus to the development of the emulsion coupling technology, which is a powerful tool for the quantitative and highly parallel measurement of protein and protein interactions. I am generally interested in being involved in the development of innovative molecular biological methods that can be used to gain new insights about biological issues. I am particularly curious to unravel the complex and often poorly understood protein interaction pathways that are the cornerstone of understanding cellular functionality and are a fundamental necessity to describe life mechanistically.

Bioprinting can be considered as a progression of the classical tissue engineering approach, in which cells are randomly seeded into scaffolds. Bioprinting offers the advantage that cells can be placed with high spatial fidelity within three-dimensional tissue constructs. A decisive factor to be addressed for bioprinting approaches of artificial tissues is that almost all tissues of the human body depend on a functioning vascular system for the supply of oxygen and nutrients. In this study, we have generated cuboid prevascularized bone tissue constructs by bioprinting human adipose-derived mesenchymal stem cells (ASCs) and human umbilical vein endothelial cells (HUVECs) by extrusion-based bioprinting and drop-on-demand (DoD) bioprinting, respectively. The computer-generated print design could be verified in vitro after printing. After subcutaneous implantation of bioprinted constructs in immunodeficient mice, blood vessel formation with human microvessels of different calibers could be detected arising from bioprinted HUVECs and stabilization of human blood vessels by mouse pericytes was observed. In addition, bioprinted ASCs were able to synthesize a calcified bone matrix as an indicator of ectopic bone formation. These results indicate that the combined bioprinting of ASCs and HUVECs represents a promising strategy to produce prevascularized artificial bone tissue for prospective applications in the treatment of critical-sized bone defects.

In tissue engineering applications, vascularization can be accomplished by coimplantation of tissue forming cells and endothelial cells (ECs), whereby the latter are able to form functional blood vessels. The use of three-dimensional (3D) bioprinting technologies has the potential to improve the classical tissue engineering approach because these will allow the generation of scaffolds with high spatial control of endothelial cell allocation. This study focuses on a side by side comparison of popular commercially available bioprinting hydrogels (Matrigel, fibrin, collagen, gelatin, agarose, Pluronic F-127, alginate, and alginate/gelatin) in the context of their physicochemical parameters, their swelling/degradation characteristics, their biological effects on vasculogenesis-related EC parameters and their printability. The aim of this study was to identify the most suitable hydrogel or hydrogel combination for inkjet printing of ECs to build prevascularized tissue constructs. Most tested hydrogels displayed physicochemical characteristics suitable for inkjet printing. However, Pluronic F-127 and the alginate/gelatin blend were rapidly degraded when incubated in cell culture medium. Agarose, Pluronic F-127, alginate and alginate/gelatin hydrogels turned out to be unsuitable for bioprinting of ECs because of their non-adherent properties and/or their incapability to support EC proliferation. Gelatin was able to support EC proliferation and viability but was unable to support endothelial cell sprouting. Our experiments revealed fibrin and collagen to be most suitable for bioprinting of ECs, because these hydrogels showed acceptable swelling/degradation characteristics, supported vasculogenesis-related EC parameters and showed good printability. Moreover, ECs in constructs of preformed spheroids survived the printing process and formed capillary-like cords. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 935-947, 2018.

Gynecomastia is a common finding in the male population which is mostly idiopathic. The aim of our study was to analyze the histological differences in young and old patient groups and its association with recurrence rates.Three hundred and five gynecomastia patients (555 breasts) undergoing surgical treatment from 1997 to 2015 were divided into four groups: Group 1: 13-17 years, Group 2: 18-30 years, Group 3: 31-49 years and Group 4: 50-83 years. They were evaluated concerning clinical classification, histological differences and association with antiandrogen or steroids/immunosuppressive therapy.We found that the rate of florid gynecomastia was higher in older patient groups, while fibrous gynecomastia was more common in adolescents and young adults (p = .0180). Glandular gynecomastia was more frequent in younger patients, while in the older patient groups, lipomatous gynecomastia was more common (p = .0006). Patients presenting with florid gynecomastia showed a higher rate of recurrence than patients with the fibrous type of gynecomastia (12.5 and 4.7%, respectively). Of note, 18.75% of florid gynecomastia was associated with antiandrogen agents or steroid/immunosuppressive therapy, while only 4.69% of fibrous gynecomastia was associated with antiandrogenic or immunosuppressive therapy. However, there was no increase of recurrence rates in patients using antiandrogen agents or undergoing steroid/immunosuppressive therapy.Fibrous gynecomastia was found to be more common in adolescents and young adults, while the florid type was more frequent in older patients. Patients presenting with florid gynecomastia showed a higher rate of recurrence than patients with the fibrous type of gynecomastia.

Mesenchymal stem cells (MSCs) represent a very attractive cell source for tissue engineering applications aiming at the generation of artificial bone substitutes. The use of three-dimensional bioprinting technologies has the potential to improve the classical tissue engineering approach because bioprinting will allow the generation of hydrogel scaffolds with high spatial control of MSC allocation within the bioprinted construct. In this study, we have performed direct comparisons between commercially available hydrogels in the context of their cytocompatibility toward MSCs and their physicochemical parameters with the aim to identify the most suitable hydrogel for drop-on-demand (DoD) printing of MSCs. In this context, we examined matrigel, fibrin, collagen, gelatin, and gelatin/alginate at various hydrogel concentrations. Matrigel, fibrin, collagen, and gelatin were able to support cell viability, but the latter showed a limited potential to promote MSC proliferation. We concentrated our study on fibrin and collagen hydrogels and investigated the effect of hydroxyapatite (HA) inclusion. The inclusion of HA enhanced proliferation and osteogenic differentiation of MSCs and prevented degradation of fibrin in vitro. According to viscosity and storage moduli measurements, HA-blends displayed physicochemical characteristics suitable for DoD printing. In bioprinting experiments, we confirmed that fibrin and collagen and their respective HA-blends represent excellent hydrogels for DoD-based printing as evidenced by high survival rates of printed MSCs. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3231-3241, 2017.

Summary Background Free functional muscle transfers represent the ‘criterion standard' for smile reconstruction in facial paralysis. The gracilis muscle is a common donor muscle; however, no data exist regarding the volume of the muscle tissue that is necessary for symmetric commissure excursion. Methods All patients with facial paralysis receiving a free functional muscle transfer for facial reanimation surgery between January 2009 and November 2015 were retrospectively analysed. Only patients with unilateral facial paralysis and documented weight of the muscle portion were included. The extent of oral commissure amplitude was determined from standardised photographs. Results In total, 42 free functional gracilis transfers were performed during the study period, of which 22 met the inclusion criteria. Eight muscles were innervated by a cross-facial nerve graft (CFNG) and 14 by the masseteric nerve. Segments between 19 and 50 g of weight (mean: CFNG, 33.9 g and masseteric nerve, 31.7 g; p = 0.59) were transferred. Coaptation to the masseteric nerve led to increased commissure excursion compared to coaptation to the CFNG. We observed a significant increase in commissure excursion with increasing muscle weight in the masseteric nerve group. In this group, four patients underwent secondary flap debulking in flaps weighing ≥27 g. In the CFNG group, only one patient, who had an initial flap weight of 50 g, underwent secondary flap reduction. Thinning reduced the oral commissure movement but improved the symmetry of commissure excursion and the aesthetic result. Conclusion The ideal muscle weight depends on the donor nerve and should be smaller for masseteric nerve than for CFNG coaptation in adults.

Active nutrient supply and waste product removal are key requirements for the fabrication of long-term viable and functional tissue constructs of considerable size. This work aims to contribute to the fabrication of artificial perfusable networks with a bioprinting process, based on drop-on-demand (DoD) printing of primary endothelial cell (EC) suspension bioink (25 × 106 ± 3 × 106 cells/ml). The process results in prescribed lumen between two hydrogel layers, allowing its integration in common layering based bioprinting processes. Low volume bioink droplets (appr. 10 nl) as building blocks were deposited between two fibrin or Collagen I layers to realize shapeable, cell-rich aggregates. Unattainable with manual positioning, DoD printing allowed precise fabrication of various designs, such as spheroidal-, line-shaped, and Y-branch cellular structures, with a mean lateral extension of 285 ± 81 μm. For basic characterization, the cell suspension building blocks were systematically compared with preformed spheroids of the same cell type, passage, and number. Post printing investigations of initially loose cell arrangements showed self-assembly and formation of central lumen with a mean cross-sectional area of Olumen = 6,400 μm2 at Day 3, lined by a single layer of CD31 positive ECs, as evaluated by confocal microscopy. Originating from this main lumen smaller, undirected side branches (Obranches = 740 μm2 ) were formed by sprouting cells, inducing a first step towards a simplistic hierarchically organized network. These lumen could prospectively help for tissue construct perfusion in vitro or, potentially, as niche for angiogenesis of host vascularization in implants.

The incidence of scalp tumors requiring radical excision increases with age. Free flap surgery is the standard reconstructive option for large defects; however, there is an ongoing uncertainty about its safety in the elderly. We conducted a review of data and report on 19 patients aged ≥75 years and 13

Vascularization is important for bone development, fracture healing and engineering of artificial bone tissue. In the context of bone tissue engineering, it was shown that coimplantation of human primary umbilical vein endothelial cells (HUVECs) and human osteoblasts (hOBs) results in the formation of functional blood vessels and enhanced bone regeneration. Implanted endothelial cells do not only contribute to blood vessel formation, but also support proliferation, cell survival and osteogenic differentiation of coimplanted hOBs. These effects are partially mediated by direct heterotypic cell contacts. In a previous report we could show that cocultivated hOBs strongly increase the expression of genes involved in extracellular matrix (ECM) formation in HUVECs, suggesting that ECM may be involved in the intercellular communication between hOBs and HUVECs. The present study aimed at investigating whether comparable changes occur in hOBs. We therefore performed a microarray analysis of hOBs cultivated in direct contact with HUVECs, revealing 1,004 differentially expressed genes. The differentially expressed genes could be assigned to the functional clusters ECM, proliferation, apoptosis and osteogenic differentiation. The microarray data could be confirmed by performing quantitative real time RT-PCR on selected genes. Furthermore, we could show that the ECM produced by HUVECs increased the expression of the osteogenic differentiation marker alkaline phosphatase (ALP) in hOBs. In summary, our data demonstrate that HUVECs provoke complex changes in gene expression patterns in cocultivated hOBs and that ECM plays and important role in this interaction. J. Cell. Biochem. 117: 1869-1879, 2016. © 2016 Wiley Periodicals, Inc.

Fragestellung: Fingeramputationsverletzungen der Zone 1 und 2 nach Tamai stellen gewöhnlich lediglich eine relative Replantationsindikation dar. Im Gegensatz zur primären Stumpfbildung sind Replantationen sehr aufwändig und erfordern spezielle supermikrochirurgische Fähigkeiten, [zum vollständigen Text gelangen Sie über die oben angegebene URL], 59. Kongress der Deutschen Gesellschaft für Handchirurgie

The most common donor-site for autologous breast reconstruction is the abdomen. Over the past several decades technical advances have resulted in the development of flaps that have been associated with a progressive decrease in abdominal wall morbidity. However, controversy exists related to the differences between muscle-sparing (MS)-TRAM and deep inferior epigastric perforator (DIEP) flaps. Hence, the question which approach should be considered standard of care remains unanswered. To address this question the current literature and published evidence was critically reviewed and discussed by an expert panel at the 39th Annual Meeting of the German-speaking Society for Micro surgery of the Peripheral Nerves and Vessels (DAM). Based on this discussion a consensus statement was developed that incorporates contemporary data regarding postoperative complication rate, donor site morbidity, as well as expert opinion regarding technical details in autologous breast reconstruction with free TRAM and DIEP flaps.Die Brustrekonstruktion mit freiem Gewebetransfer vom Unterbauch als (muskelsparende) TRAM oder DIEP Lappenplastik stellt das Standardverfahren der autologen Brustrekonstruktion dar. Durch operative Fortschritte ist es gelungen die Hebedefektmorbidität durch muskelsparende bzw. perforatorbasierte Techniken zu minimieren. Hier stellt sich die Frage, in wie weit dies als ein notwendiger Standard angesehen werden kann oder ob auch Lappenplastiken mit Muskelanteilen (MS-TRAM) noch als zeitgemäß anzusehen sind. In einem Konsensusworkshop der 3 Jahrestagung der Deutschsprachigen Arbeitsgemeinschaft für Mikrochirurgie der peripheren Nerven und Gefäße (DAM) wurde die Datenlage kritisch geprüft und durch eine Expertengruppe ein Konsensus erarbeitet. Dieser beinhaltet neben den aktuellen Daten zu Lappensicherheit und Hebedefektmorbidität aus der Literatur auch ein aktuelles Meinungsbild der Expertengruppe bzgl. verschiedener technischer Details des operativen Vorgehens.

Summary Background Rejuvenation procedures of the periorbital region and the forehead, with the eyebrow as a key structure, are often performed in plastic surgery. There is no common consent on the changes of aging in this region and the consecutive treatment options. This study was designed to support the body of literature with a broader data basis about the natural changes of eyebrow position and its shape. Methods The brow shape, the lid axis, and the distance between both medial canthi (DMC) were analyzed retrospectively on randomly selected standardized photographs of healthy Caucasian females and males. Six defined heights of the upper brow border, including the position and height of the highest brow point (HBP) and the angle of the upper brow line, were measured. Results A total of 244 Caucasian females and males in two groups ( 55 years) were analyzed. The data showed a difference between brow shapes of young females and males, especially relating to the HBP, which is located medially in young females. The brow shape of females assimilates toward a male shape with aging. The eyebrow moves upward, the DMC widens, and the lid axis drops laterally in both sexes with aging. Conclusions Our data suggest that rejuvenation procedures should focus on not only lifting the brow but also reshaping and stabilizing the brow, especially the HBP, which plays an important role in defining the upper brow line. Our findings can explain why lifting the brow can create not only an undesired surprise but also an older look.

Summary Background Synchronicity of the oral commissure movement of a bilateral smile is a significant goal for reconstruction in facial reanimation and may only be guaranteed with use of the facial nerve as a donor nerve. Yet over the years several studies report some degree of spontaneity in certain patients when using a non-facial donor nerve, which indicates that synchronous initiation of the smile might be achievable with other donor nerves. We designed a prospective cohort study to evaluate whether pre-operative involuntary activation of the masseteric nerve during smile predicts development of a synchronous smile development when using the masseteric nerve for reanimation. Methods In a prospective cohort study unilateral long-standing facial palsy patients scheduled for dynamic smile reanimation with a free functional muscle transplant using the masseteric nerve as a donor nerve were preoperatively evaluated via EMG for involuntary activation of the masseter muscle upon smiling, which we called coactivation. Postoperatively, six months after noting the first muscle contraction smile synchronicity was evaluated. We analyzed the synchronicity of the bilateral smile development by analyzing slow-motion video sequences of the patients that were taken while the patients were watching funny video sequences. Results were then correlated with the pre-operative EMG. Results 30 patients were recruited for this prospective study and underwent facial reanimation surgery with a free gracilis transfer innervated by the masseteric nerve. 19 patients demonstrated involuntary coactivation of the masseter muscle upon smiling and 11 did not. Postoperatively all patients could demonstrate a voluntary smile. 94% of patients who had preoperative coactivation showed a synchronous movement of the oral commissure when smiling. In those patients, that did not show activation of the masseter muscle upon smiling 0% showed synchronicity. The preoperative coactivation of the masseter muscle is able to predict the outcome regarding synchronicity of the smile with a sensitivity of 99.7%, a specificity of 88.5% and 92.5% positive predictive value and 99.6% negative predictive value (p Conclusions The lack of masseter co-activation with smile predicts a lack of spontaneous involuntary smile after dynamic smile reconstruction using the masseteric nerve.

Vascularization is essential in bone tissue engineering and recent research has focused on interactions between osteoblasts (hOBs) and endothelial cells (ECs). It was shown that cocultivation increases the stability of osteoblastic alkaline phosphatase (ALP) mRNA. We investigated the mechanisms behind this observation, focusing on mRNA binding proteins. Using a luciferase reporter assay, we found that the 3′-untranslated region (UTR) of ALP mRNA is necessary for human umbilical vein endothelial cells (HUVEC)-mediated stabilization of osteoblastic ALP mRNA. Using pulldown experiments and nanoflow-HPLC mass spectrometry, vimentin was identified to bind to the 3′-UTR of ALP mRNA. Validation was performed by Western blotting. Functional experiments inhibiting intermediate filaments with iminodipropionitrile and specific inhibition of vimentin by siRNA transfection showed reduced levels of ALP mRNA and protein. Therefore, ALP mRNA binds to and is stabilized by vimentin. This data add to the understanding of intracellular trafficking of ALP mRNA, its function, and have possible implications in tissue engineering applications.

Increasing evidence indicates that sialic acid plays an important role during nerve regeneration. Sialic acids can be modified in vitro as well as in vivo using metabolic oligosaccharide engineering of the N-acyl side chain. N-Propionylmannosamine (ManNProp) increases neurite outgrowth and accelerates the reestablishment of functional synapses in vitro. We investigated the influence of systemic ManNProp application using a specific in vivo mouse model. Using mice expressing axonal fluorescent proteins, we quantified the extension of regenerating axons, the number of regenerating axons, the number of arborising axons and the number of branches per axon 5 days after injury. Sciatic nerves from non-expressing mice were grafted into those expressing yellow fluorescent protein. We began a twice-daily intraperitoneal application of either peracetylated ManNProp (200 mg/kg) or saline solution 5 days before injury, and continued it until nerve harvest (5 days after transection). ManNProp significantly increased the mean distance of axonal regeneration (2.49 mm vs. 1.53 mm; P < 0.005) and the number of arborizing axons (21% vs. 16%; P = 0.008) 5 days after sciatic nerve grafting. ManNProp did not affect the number of regenerating axons or the number of branches per arborizing axon. The biochemical glycoengineering of the N-acyl side chain of sialic acid might be a promising approach for improving peripheral nerve regeneration.

Although perioral aging is highly individual with several distinct processes taking part simultaneously, there is scarce systematic information which helps to indicate the right rejuvenation approach among the multitude of proposed procedures. Existing data about perioral aging has not yet been transformed into a consistent therapeutic concept. The intention of this study was to provide a simple, yet reproducible classification and to offer appropriate rejuvenation approaches. To identify reliable and constant landmarks of the ongoing process of perioral aging, 462 perioral photo documentations were morphometrically analyzed. Based upon the identified landmarks a two-dimensional classification was developed. The classification was validated by three plastic surgeons. Inter- and intra-rater reliability was calculated using Cohen’s kappa coefficient. Perioral aging can be broken down into changes of the lip shape and changes of the lip surface. Both processes can be classified into three stages each: Lip shape according to the shape in profile view, the lip length in relation to the frontal incisors, and the degree of vermilion inversion. Lip surface according to the presence and degree of radial wrinkles and the visibility of the structural elements Cupid’s bow, philtrum, and white roll. Inter-observer reliability was rated very good (kappa values between 0.819 and 0.963) and perfect for intra-observer reliability (1.0). A better understanding of perioral aging leads to a simple classification for the aging lips. Using the classification helps to tailor an appropriate treatment to the individual patient and aids to achieve a natural rejuvenation result. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

PURPOSE Facial paralysis has a profound impact on functionality and esthetics of the oral region. In patients with strong skin laxity and soft tissue ptosis, functional smile reconstruction is challenging due to the accentuated asymmetry at rest. Thus, the purpose of the study was to analyze facial symmetry in this patient clientele following a combination of dynamic reanimation with fascial strips for static suspension compared to functional gracilis transfer alone. METHODS In 2014, we altered the single-stage approach for microsurgical smile reconstruction in patients with significant soft tissue ptosis by adding fascia lata grafts for static support. We evaluated 6 patients (mean age 57.8 ± 5.2, group A) who underwent the combined procedure, and compared their results to 6 patients with flaccid facial paralysis who were treated before 2014 and received a functional gracilis transfer alone (mean age 52.5 ± 7.5, group B). To test the efficacy of the technique, we retrospectively analyzed the correction of the oral asymmetry as well as nasal and philtral deviation by computer-assisted photograph analysis 6 months postoperatively. RESULTS The comparative analysis revealed a significant postoperative improvement of the oral asymmetry (A: 90.0 ± 5.0% relative correction at rest vs. B: 62.6 ± 17.2%, P

There are only relative indications for distal digital replantation in zones 1 and 2 according to Tamai. In contrast to primary closure for fingertip amputations, replantation is a complex procedure that requires skills in supermicrosurgical techniques, as vessels with diameters between 0.3-0.8 mm are connected. In addition the time spent in hospital and the time off from work are longer. Distal digital replantation is thus only indicated, if the expected functional and aesthetic benefits surmount those of primary closure. We retrospectively analysed all fingertip amputations in zone 1 and 2 according to Tamai between 9/2009 and 7/2014 where we attempted distal digital replantation. The success of replantation, wound healing and functional results were evaluated according to Yamano. We performed 11 distal digital replantations in the study period. There were 6 total amputations, 4 subtotal amputations and 1 avulsion of the digital pulp. Revascularisation with long-term reattachment of the amputated tissues was possible in 8 cases (73%). In 3 cases (27%) secondary amputation closure was necessary. The mean operating time was 3 h 56 min. 6 patients, which had a successful replantation, were available for follow-up examinations after a mean period of 19 months. 5 patients were satisfied with the result and would again prefer replantation over primary amputation closure. 4 patients reported a good function of the replanted digits and did not complain about any limitations in their use. 2 patients complained about restricted function. All patients could return to their previous places of employment and were free of pain. Of the 12 affected digital nerves 11 nerves had a 2-point discrimination (2-PD) of ≤15 mm, 3 of them had a 2-PD between 7 and 10 mm and 4 of them of6 mm. Soft tissue atrophy was obvious in 3 replanted digits and nail deformities in 2 patients. Distal digital replantation is complex and technically challenging. It leads to high patient satisfaction with only minimal functional limitations, if successful. Due to the good results that can be obtained by these procedures, fingertip replantation should be attempted, if operative risks are minimal and if requested by the patient.

Mesenchymal stem cells (MSCs) represent a very attractive cell source for tissue engineering applications aiming at the generation of artificial bone substitutes. The use of three-dimensional bioprinting technologies has the potential to improve the classical tissue engineering approach because bioprinting will allow the generation of hydrogel scaffolds with high spatial control of MSC allocation within the bioprinted construct. In this study, we have performed direct comparisons between commercially available hydrogels in the context of their cytocompatibility toward MSCs and their physicochemical parameters with the aim to identify the most suitable hydrogel for drop-on-demand (DoD) printing of MSCs. In this context, we examined matrigel, fibrin, collagen, gelatin, and gelatin/alginate at various hydrogel concentrations. Matrigel, fibrin, collagen, and gelatin were able to support cell viability, but the latter showed a limited potential to promote MSC proliferation. We concentrated our study on fibrin and collagen hydrogels and investigated the effect of hydroxyapatite (HA) inclusion. The inclusion of HA enhanced proliferation and osteogenic differentiation of MSCs and prevented degradation of fibrin in vitro. According to viscosity and storage moduli measurements, HA-blends displayed physicochemical characteristics suitable for DoD printing. In bioprinting experiments, we confirmed that fibrin and collagen and their respective HA-blends represent excellent hydrogels for DoD-based printing as evidenced by high survival rates of printed MSCs. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3231-3241, 2017.

C-reactive protein (CRP) concentrations rise in response to tissue injury or infection. Circulating pentameric CRP (pCRP) localizes to damaged tissue where it leads to complement activation and further tissue damage. In-depth knowledge of the pCRP activation mechanism is essential to develop therapeutic strategies to minimize tissue injury. Here we demonstrate that pCRP by binding to cell-derived microvesicles undergoes a structural change without disrupting the pentameric symmetry (pCRP*). pCRP* constitutes the major CRP species in human-inflamed tissue and allows binding of complement factor 1q (C1q) and activation of the classical complement pathway. pCRP*–microvesicle complexes lead to enhanced recruitment of leukocytes to inflamed tissue. A small-molecule inhibitor of pCRP (1,6-bis(phosphocholine)-hexane), which blocks the pCRP–microvesicle interactions, abrogates these proinflammatory effects. Reducing inflammation-mediated tissue injury by therapeutic inhibition might improve the outcome of myocardial infarction, stroke and other inflammatory conditions., C-reactive protein is a pentameric protein secreted by the liver in response to injury and infection. Here Braig et al. show that conformational changes in CRP on the surface of monocyte-derived microvesicles enable binding of complement C1q and lead to activation of the complement cascade and aggravation of inflammation.

In tissue engineering applications, vascularization can be accomplished by coimplantation of tissue forming cells and endothelial cells (ECs), whereby the latter are able to form functional blood vessels. The use of three-dimensional (3D) bioprinting technologies has the potential to improve the classical tissue engineering approach because these will allow the generation of scaffolds with high spatial control of endothelial cell allocation. This study focuses on a side by side comparison of popular commercially available bioprinting hydrogels (Matrigel, fibrin, collagen, gelatin, agarose, Pluronic F-127, alginate, and alginate/gelatin) in the context of their physicochemical parameters, their swelling/degradation characteristics, their biological effects on vasculogenesis-related EC parameters and their printability. The aim of this study was to identify the most suitable hydrogel or hydrogel combination for inkjet printing of ECs to build prevascularized tissue constructs. Most tested hydrogels displayed physicochemical characteristics suitable for inkjet printing. However, Pluronic F-127 and the alginate/gelatin blend were rapidly degraded when incubated in cell culture medium. Agarose, Pluronic F-127, alginate and alginate/gelatin hydrogels turned out to be unsuitable for bioprinting of ECs because of their non-adherent properties and/or their incapability to support EC proliferation. Gelatin was able to support EC proliferation and viability but was unable to support endothelial cell sprouting. Our experiments revealed fibrin and collagen to be most suitable for bioprinting of ECs, because these hydrogels showed acceptable swelling/degradation characteristics, supported vasculogenesis-related EC parameters and showed good printability. Moreover, ECs in constructs of preformed spheroids survived the printing process and formed capillary-like cords. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 935-947, 2018.

Im klinischen Alltag auf einer chirurgischen Station einer Kinderklinik oder eines Krankenhauses steht die medizinische Behandlung im Vordergrund, insbesondere nach schweren Unfallen. Die Behandlung alleine stellt eine grose Herausforderung fur das gesamte Team dar. In einem hektischen klinischen Alltag gilt es trotz alledem, dass sich jeder Einzelne und das ganze Team zusammen daruber im Klaren sind, wie wichtig es ist, auf das jeweilige Kind und dessen Familie adaquat und mit Geduld einzugehen. Aber auch kleinere Verletzungen und elektive Behandlungen stellen fur Kinder noch mehr als fur Erwachsene eine angstbeladene Situation dar, welche einer besonderen Herangehensweise bedarf. Wir sollten den Fokus auf die Notwendigkeit der altersentsprechenden und individuellen Behandlung und Betreuung von Kindern, vom Neugeborenen bis hin zum Adoleszenten legen.

Komplexe chirurgische Eingriffe bei Kindern waren vor der Ara der Narkose kaum moglich; diese erlaubte dann im 19. Jahrhundert bereits grose Fortschritte bei Spaltenkorrekturen. Die Subspezialisierung der Chirurgie fuhrte dann im 20. Jahrhundert zu grosen Fortschritten vor allem bei der Behandlung von Fehlbildungen (Hand, kraniofazial, Spalten) und Verbrennungsopfern in spezialisierten Zentren und zu technologischen Innovationen (Mikrochirurgie, Osteosynthesen, Expander). In jungerer Zeit etabliert sich zunehmend die Erkenntnis, dass padiatrische plastische Chirurgie auch spezifische soziale und psychologische Aspekte berucksichtigen muss.

Plastische Chirurgie betrifft fast immer sowohl Funktion als auch Erscheinung, denn auch das Aussehen jedes Menschen und schon des Kindes hat auch eine psychosoziale und psychologische Funktion fur die Selbst- und Fremdwahrnehmung. Die fehlende Autarkie des Kindes und komplexe Beziehungsgeflecht Patient–Familie–Umwelt–Arzt stellt eine spezielle ethische Herausforderung fur den Chirurgen dar, der hier noch weit mehr als sonst mehr als technische und Erwagungen berucksichtigen muss. Rein asthetische Eingriffe bei prinzipiell »normalem« ohne Stigmatisierungsmerkmale stellen derzeit eher noch die Raritat dar. Sozialer und medialer Druck in Richtung asthetischer Idealziele darf aber arztlich nicht gefordert werden.

Interscapulothoracic amputation (ISTA) encompasses the removal of the upper limb, scapula and clavicle. As the reconstructive and oncologic limb-saving techniques improved, the indications for this formidable procedure decreased. However, it is still the appropriate procedure in cases with extensive oncologic or traumatic involvement of the shoulder girdle. Following ISTA, the surgeon is not only faced with a large defect but also with severe functional and aesthetic impairments. A solution to these problems is the immediate reconstruction with a free composite transfer from the amputated extremity. We successfully treated three oncologic cases and one traumatic case using this technique. The recipient vessels included the subclavian artery and vein in three cases and the internal thoracic vessels in one case. After a mean follow-up time of 4.5 years, two of the three tumour patients were free of recurrent disease. In all cases stable wound closure was achieved. Three out of four patients would opt for surgery again, in spite of the high occurrence of complications. One patient died after a 14-year event-free postoperative course. We conclude that the defect following ISTA can be successfully covered using a free composite tissue transfer of the amputated disease-free elbow and forearm, while simultaneously reconstructing the shoulder silhouette and axilla. This procedure reduces functional and aesthetic impairments and improves the quality of life.

Neovascularization of adipose tissue equivalents is a crucial step in successful adipose tissue engineering, since insufficient vascularization results in graft resorption in an in vivo situation. A possible cellular approach to overcome this limitation is the co-implantation of adipose-derived stem cells (ASCs) with endothelial cells to stimulate the formation of a vascular network. We investigated the potential of ASCs derived from human abdominal fat tissue co-cultured with endothelial progenitor cells (EPCs) from human peripheral blood to stimulate neovascularization of fibrin constructs on the chorioallantoic membrane (CAM) of fertilized chicken eggs, in direct comparison to human umbilical vein endothelial cells (HUVECs). After 9 days of incubation, cell-fibrin constructs were explanted and histologically evaluated with respect to ingrowth of avian blood vessels into the construct and formation of human blood vessels by co-implanted endothelial cells. When administered on the CAM, ASCs successfully guided host vasculature into the construct (angiogenesis) and guided formation of capillary-like structures by co-implanted human endothelial cells (vasculogenesis), with HUVECs being superior to EPCs, leading to a perfused avian and human capillary network within the fibrin construct. However, the results also showed that perfused human blood vessels were only observed near the CAM compared to unperfused capillary-like structures near the top of the construct, indicating that perfusion of the cell-fibrin construct takes longer than 9 days. In conclusion, as blood vessel formation is an essential step during adipogenic differentiation, the data support our hypothesis that cellular communication between transplanted ASCs and endothelial cells is beneficial for vasculogenesis. Copyright © 2013 John Wiley & Sons, Ltd.

Our current knowledge of the pathophysiological sequelae of ischemia or reperfusion (I/R) injury in free tissue transfer in reconstructive surgery is based on data obtained in animal experiments. In this study, we investigated the histologic and molecular changes after 11 free microsurgical muscle transfers in human muscle tissue.Biopsies of free muscle flap tissue were taken immediately before clipping of the pedicle and 5 days after ischemia and successful microanastomosis and restoration of the blood flow. Samples were analyzed histologically for edema formation and by immunohistochemistry for infiltration of inflammatory cells and angiogenesis. Expression levels of the inflammatory marker proteins interleukin-1β and tumor necrosis factor α and of complement component 3 as a major mediator of I/R injury were analyzed by real-time polymerase chain reaction. A TUNEL (terminal desoxynucleotidyl transferase-mediated-dUTP-nick-end-labeling) assay was used to assess apoptosis levels within the human muscle tissue.I/R injury leads to a significant up-regulation of inflammatory parameters, infiltration of inflammatory cells, and angiogenesis. Increased complement component 3 deposition and apoptosis of cells were accompanied by interstitial edema as indication for a pronounced postischemic inflammatory reaction within the muscle tissue after free tissue transfer.Our findings of molecular changes induced by I/R injury in human striated muscle tissue validate data obtained in animal models of I/R injury. The parameters and inflammatory patterns defined in this study will allow for the monitoring of the success of novel pharmaceutical strategies in the future and will help to transfer data obtained in animal work to the in vivo setting in human beings.

Background: Lymphedema results from insufficient lymphatic drainage and typically affects the extremities. Recent studies revealed obesity as another cause of extremity lymphedema. Conservative treatment of patients with elephantiastic lymphedema of the lower extremity is limited and often inadequate.[for full text, please go to the a.m. URL], 47. Jahrestagung der Deutschen Gesellschaft der Plastischen, Rekonstruktiven und Ästhetischen Chirurgen (DGPRÄC), 21. Jahrestagung der Vereinigung der Deutschen Ästhetisch-Plastischen Chirurgen (VDÄPC)

Defektdeckung mit temporoparietalem Faszienlappen. Dunner, gut durchbluteter, ein- oder zweischichtiger Faszienlappen. Verwendung als sensible fasziokutane lokale Lappenplastik, als Mehrkomponententransplantat osteofaszial mit und ohne behaarte Kopfhaut sowie als zweischichtiges Sehnengleitlager moglich. Maximal 17 × 14 cm grose Weichteildefekte. Absolut: Vorschadigung des Lappens bzw. Lappenstiels, Arteriitis temporalis, Defekte mit Volumenverlust, Moyamoya-Syndrom. Relativ: Alopezie im Bereich der Schnittfuhrung. Praoperative dopplersonographische Darstellung der Stielgefase (A. temporalis superficialis mit Endasten und Begleitvene). Anzeichnen der Schnittfuhrung. Unterspritzung mit verdunnter Adrenalinlosung. Darstellung der temporoparietalen Faszie und Stielgefase, wobei die Schonung der Haarbalge besonderer Aufmerksamkeit bedarf. Primarverschluss des Hebedefekts. Vollhaut oder Spalthautdeckung des Lappens und Vakuumversiegelung bzw. Anlage eines Uberknupfverbands. Ruhigstellung bei Defektdeckung an den Extremitaten in Lappenentlastungsposition, Hochlagerung zur Unterstutzung des venosen Abflusses. Entfernung der Vakuumversiegelung bzw. des Uberknupfverbands am 5. postoperativen Tag. Beginn des Lappentrainings ab dem 7. postoperativen Tag. Fadenzug/Klammerentfernung an der Lappenentnahmestelle nach 5–7 Tagen, an der Empfangerregion nach 8–10 Tagen. Kompressionsbehandlung durch elastische Verbandsanlage oder Tragen eines Kompressionsuberzugs. Bei 8 Patienten wurde der temporoparietale Faszienlappen zur Rekonstruktion von Weichteildefekten verwendet. In 2 Fallen kam der Lappen gestielt zur Anwendung. Die mittlere Einheilungszeit betrug 16,3 Tage, die mittlere Nachuntersuchungszeit 13,4 Monate. In allen Fallen konnte eine erfolgreiche Rekonstruktion mit gutem funktionellem und asthetisch ansprechendem Ergebnis erzielt werden. Komplikationen wurden bei 3 Patienten beobachtet. Diese waren in einem Fall die iatrogene Schadigung des R. frontalis n. facialis, das Auftreten einer Alopezie an der Lappenentnahmestelle in einem weiteren Patienten und letztlich die Notwendigkeit der fruhzeitigen (erfolgreichen) Revision bei Beeintrachtigung der Lappendurchblutung.

Background: Radical surgical resection remains the single-most important treatment in the curative multimodal therapy of soft tissue sarcomas. Refinements in surgical techniques have resulted in the development of function preserving approaches increasingly avoiding limb amputation. Patients and methods: The records of all patients (n = 34) who underwent microsurgical soft tissue coverage subsequent to primary resection of soft tissue sarcoma of the upper or lower limb from 1999 to 2009 are reviewed regarding postoperative complications, time until start of adjuvant radiation and functional outcome (Toronto Extremity Salvage Score, TESS). Results: Thirty-four patients (range: 21–86 years) received a total of 35 free flaps. Complete tumor resection was obtained in 33 patients, one patient required re-excision ultimately resulting in tumor-free margin status (R0 resection). Major complications were encountered in four cases including one patient with complete flap loss requiring an additional free flap and three patients with partial flap loss requiring split-thickness skin graft procedures. Minor complications were observed in three patients (9%). Extremity salvage could be achieved in 33 patients with adequate postoperative ambulation (TESS 84 ± 18) and adequate use of the upper extremity (TESS 80 ± 22). One patient underwent amputation. Mean time until start of adjuvant radiotherapy was 37 days (range 24–56 days). Conclusion: A synergetic center-based interdisciplinary approach is crucial in therapeutical management of soft tissue sarcomas with the aim of R0 resection status and limb preservation. Plastic surgery contributes by offering microsurgical reconstruction using free tissue transfer, thus broadening surgical possibilities. This increases the chance of both adequate oncosurgical resection and limb preservation. © 2011 Wiley-Liss, Inc. Microsurgery 2011.

Prior to the advent of a multidisciplinary approach to the treatment of soft-tissue sarcomas, surgical treatment consisted of extremity amputation. Advances in treatment modalities such as radiotherapy allowed more limited resections with similar survival rates. As local control is the primary objective in the management of these neoplasms, distally located tumours pose a particular reconstructive challenge. Limb preservation is now possible due to the availability of microsurgical techniques. A retrospective analysis was conducted assessing the suitability of the free anterolateral thigh (ALT) flap for distal-extremity reconstruction after wide local excision of sarcomas. Nine patients were included in the study with a median follow-up period of 36 months. In all patients, tumours were located at or distal to the elbow and knee, respectively. All flaps survived. In one patient, the ALT donor site was addressed with a split-thickness skin graft after wound dehiscence was observed postoperatively after initial primary closure. The free ALT perforator flap is an ideal flap for the reconstruction of distal-extremity defects after sarcoma resection as it allows coverage of large skin defects with minimal donor-site morbidity. Its thinness addresses the shallow defects typically encountered in the distal extremity and thus avoids the bulkiness encountered after reconstruction with musculocutaneous flaps.

Bone represents a highly dynamic tissue whose development is strongly dependent on vasculogenic and angiogenic processes. Neovascularization also plays an important role in fracture healing and in tissue engineering applications aiming at restoring bone function. We have previously shown in a heterotopic subcutaneous implantation model of severe combined immunodeficiency (SCID) mice that implanted human umbilical vein endothelial cells (HUVECs) gave rise to the formation of a complex functional human neovasculature. In this study, we investigated the effect of HUVEC coimplantation on mesenchymal stem cell (MSC)-mediated bone regeneration in an orthotopic calvarial bone defect model in immunocompromised mice. For this purpose, human fibrin/Matrigel-immobilized HUVECs and MSCs were seeded alone or in combination into scaffolds consisting of decalcified processed bovine cancellous bone (Tutobone) and implanted into calvarial critical-sized defects. Our results show that implanted HUVECs formed complex three-dimensional networks of perfused human neovessels that were stabilized by recruiting perivascular cells. Neovessel formation was considerably higher in the coimplantation group, suggesting that implanted MSCs supported HUVEC-triggered neovascularization. In addition, implanted MSCs effectively supported bone formation in calvarial defects. However, the HUVEC-derived neovasculature did not improve MSC-triggered bone regeneration in this orthotopic critical-sized defect model.

Various approaches to endoscopic carpal tunnel release have been described, including the advantages of the open compared with the endoscopic technique. However recent results suggest that both are equal in terms of outcome and morbidity. The misconception about the potential morbidity and the hope of successful conservative treatment can sometimes delay operative release of the carpal tunnel. The aim of this study was to evaluate whether the preoperative duration of symptoms influences outcome and recovery. Patients who had endoscopic release of the carpal tunnel using a modified one-port method were included in this retrospective study. Patients' satisfaction and general outcome were analysed with a questionnaire. A total of 242 patients were included in the study, and the data of 170 endoscopic decompression operations were analysed (70%). There were no major operative complications, except the conversion to open release in one case. There was a significant association between the preoperative interval of symptoms and the return to everyday activities and normal function (p0.001). Patients with longer-lasting symptoms also had reduced recovery of postoperative strength, which was negatively associated with the duration of preoperative symptoms (p0.001). Operative decompression by the endoscopic one-port method is a low risk procedure with a low morbidity. The decision for operative decompression should be made as early as possible to avoid complications seen in patients with long-lasting symptoms and permanent nerve damage.

Background: Microsurgical autologous breast reconstruction has evolved significantly over the last three decades. The muscle-sparing transverse rectus abdominis musculocutaneous (TRAM), deep inferior epigastric artery perforator, and superficial inferior epigastric artery flaps have been developed to minimize abdominal donor-site morbidity. Assuming that harvest of the superficial inferior epigastric artery flap has the same impact on abdominal wall morbidity as performing an abdominoplasty, the authors designed a matched-pair analysis comparing patients' abdominal wall strength after muscle-sparing TRAM flap reconstruction with that after abdominoplasty. Methods: A total of 104 patients were included in the study. Fifty-two TRAM flap patients were matched with 52 abdominoplasty patients for age and body mass index. Outcome measures included postoperative complications, particularly hernia and abdominal bulge formation. Two surveys were used to assess patient satisfaction as well as the impact of the procedure on everyday life. Results: Both study groups were similar with regard to age, body mass index, past medical history, and postoperative complication rate, including hernia and abdominal bulge formation. Results were similar between the study groups, with the exception of a higher rate of satisfaction with the appearance of the abdominal scar among TRAM flap patients (p = 0.03) as well a lower likelihood of TRAM flap patients to engaging in sporting activities postoperatively (p = 0.01). Conclusions: In the present study, the muscle-sparing TRAM flap did not result in a higher rate of postoperative complications related to abdominal wall morbidity. Differences observed regarding the postoperative level of activity are unlikely to be related to the surgical insult to the abdominal wall.

Regarding tissue regeneration, mechanics of biomaterials gains progressive importance. Therefore, this study reports on in situ crosslinked electrospun gelatin nonwoven mats (NWMs) whose distinct modulus of elasticity (ME) promotes epithelial tissue formation in a graded manner. NWMs, comprising fiber diameters in various distributions, yield an ME of about 2.1, 3.2, and 10.9 kPa. A two-step approach of preclinical in vitro validation identifies the elasticity of 3.2 kPa as superior to the other, regarding the histogenetic epithelial outcome. Hence, this 3.2 kPa candidate NWM is colonized with oral mucosal epithelial keratinocytes in the absence or presence of mesenchymal fibroblasts and/or endothelial cells. Evaluation of epithelial histogenesis at days 1 to 10 occurs by colorimetric and fluorescence-based immunohistochemistry (IHCH) of specific biomarkers. These include cytokeratins (CK) 14, CK1, and involucrin that indicate different stages of epithelial differentiation, as well as the basement membrane constituent collagen type IV and Ki-67 as a proliferation marker. Intriguingly, histogenesis and IHCH reveal the best resemblance of the native epithelium by the NWM alone, irrespective of other cell counterparts. These findings prove the gelatin NWM a convenient cell matrix, and evidence that NWM mechanics is important to promote epithelial histogenesis in view of prospective clinical applications.

For the regeneration of bone in tissue engineering applications, it is essential to provide cues that support neovascularization. This can be achieved by cell-based therapies using mature endothelial cells (ECs) or endothelial progenitor cells. In this context, ECs were used in various in vivo studies in combination with primary osteoblasts to enhance neovascularization of bone grafts. In a previous study, we have shown that cocultivation of human primary ECs and human primary osteoblasts (hOBs) leads to a cell contact-dependent up-regulation of alkaline phosphatase (ALP) expression in osteoblasts, indicating that cocultivated ECs may support osteogenic differentiation and osteoblastic cell functions. In the present study, we investigated this effect in more detail, revealing a time and cell number dependency of EC-mediated up-regulation of the early osteoblastic marker ALP, whereas osteocalcin, a late marker of osteogenesis, was down-regulated. The effect on ALP expression was bidirectional specific for both cell types. Functional inhibition of gap junctional communication between ECs and hOBs by 18alpha-glycyrrhetinic acid had only a weak suppressive effect on EC-mediated ALP up-regulation. In contrast, inhibition of p38 mitogen-activated protein kinase nearly completely prevented the EC-mediated stimulation of osteoblastic ALP expression. To investigate the molecular mechanism underlying the ALP up-regulation, we examined the effect of EC cocultivation on osteoblastic ALP promoter activity as well as mRNA stability. Cocultivation of ECs with hOBs significantly elevated the half-life of osteoblastic ALP mRNA without affecting its promoter activity. In summary, our data show that EC-mediated up-regulation of osteoblastic ALP expression is cell-type specific and is posttranscriptionally regulated via p38 mitogen-activated protein kinase-dependent mRNA turn-over.