Evaluation of the Suprafascial Thin ALT Flap in Foot and Ankle Reconstruction.

BACKGROUND: Distal lower extremity reconstruction can be challenging in terms of flap design. Bulky flaps result in limited mobility accompanied with the need of customized footwear. Raising the ALT-flap in a superficial fascial plane (thin ALT-flap) can be beneficial. This study evaluates thin ALT-flaps for lower distal extremity reconstruction. METHODS: In a retrospective study, patients that underwent microvascular extremity reconstruction at the level of the ankle and dorsal foot at the University of Freiburg from 2008-2018 were reviewed. RESULTS: 95 patients could be included in the study (35 perforator flaps, 8 fascia flaps and 54 muscle flaps).Among the perforator flaps, 21 ALT-flaps were elevated conventionally and 14 in the superficial fascial plane (thin ALT-flap). Among the conventional ALT-flaps, there was one flap loss (5%) and one successful revision (5%). 5(24%) flaps received secondary thinning. 57%(n = 12) were able to wear conventional footwear. There were 2(15%) successful revisions of thin ALT-flaps. 100% of thin ALT-flaps survived and 85%(n = 11) of the patients wore ordinary footwear after defect coverage.Among fascial flaps, 50%(n = 4) had to be revised with 2(25%) complete and 1 (13%) partial flap loss. All patients achieved mobility in ordinary shoes (n = 8).In muscle flaps, there were 7(13%) revisions and 5(9%) flap losses. 5(9%) flaps received secondary thinning. Only 33%(n = 18) were mobile in ordinary footwear. CONCLUSION: The thin ALT-flap is a save one-stage evolution for lower distal extremity reconstruction with a favorable flap survival rate. Compared with conventional ALT-flaps it might be beneficial in reducing the need for expensive custom fitted shoes and secondary thinning procedures.

Dermatofibrosarcoma protuberans in a young patient with epidermolysis bullosa: a case report.

BACKGROUND: Epidermolysis bullosa is a group of rare inherited skin diseases characterized by blister formation following mechanical skin trauma. Epidermolysis bullosa is associated with increased skin cancer rates, predominantly squamous cell carcinomas, yet to our best knowledge, there is no reported case of dermatofibrosarcoma protuberans in a patient with Epidermolysis bullosa. CASE PRESENTATION: Here, we present a 26-year-old man with junctional epidermolysis bullosa, who developed a DFSP on the neck. Initial, the skin alteration was mistakenly not considered malignant, which resulted in inadequate safety margins. The complete resection required a local flap to close the defect, which is not unproblematic because of the chronic inflammation and impaired healing potential of the skin due to Epidermolysis bullosa. CONCLUSIONS: To our best knowledge, this is the first reported case of a skin-associated sarcoma in a patient with EB; however, further investigation is required to verify a correlation.

Increased differentiation and production of extracellular matrix components of primary human osteoblasts after cocultivation with endothelial cells: A quantitative proteomics approach.

Coculturing of bone-forming and blood vessel-forming cells is a strategy aimed at increasing vascularity of implanted bone constructs in tissue-engineering applications. We previously described that the coculture of primary human osteoblasts (hOBs) and human umbilical vein endothelial cells (HUVECs) improves the differentiation of both cell types, leading to the formation of functional blood vessels and enhanced bone regeneration. The objective of this study was to further delineate the multifaceted interactions between both cell types. To investigate the proteome of hOBs after cocultivation with HUVECs we used stable isotope labeling by amino acids in cell culture, revealing 49 significantly upregulated, and 54 significantly downregulated proteins. Amongst the highest regulated proteins, we found the proteins important for osteoblast differentiation, cellular adhesion, and extracellular matrix function, notably: connective tissue growth factor, desmoplakin, galectin-3, and cyclin-dependent kinase 6. The findings were confirmed by enzyme-linked immunosorbent assays. We also investigated whether the mRNA transcripts correlate with the changes in protein levels by quantitative real-time reverse transcription polymerase chain reaction. In addition, the data was compared to our previous microarray analysis of hOB transcriptome. Taken together, this in-depth analysis delivers reliable data suggesting the importance of coculturing of hOBs and HUVECs in tissue engineering.

The adipofasciocutaneous gluteal fold perforator flap a versatile alternative choice for covering perineal defects.

AIM: Perineal defects following the resection of anorectal malignancies are a reconstructive challenge. Flaps based on the rectus abdominis muscle have several drawbacks. Regional perforator flaps may be a suitable alternative. We present our experience of using the gluteal fold flap (GFF) for reconstructing perineal and pelvic defects. METHODS: We used a retrospective chart review and follow-up examinations focusing on epidemiological, oncological (procedure and outcome), and therapy-related data. This included postoperative complications and their management, length of hospital stay, and time to heal. RESULTS: Twenty-two GFFs (unilateral n = 8; bilateral n = 7) were performed in 15 patients (nine women and six men; anal squamous cell carcinoma n = 8; rectal adenocarcinoma n = 7; mean age 65.5 + 8.2 years) with a mean follow-up time of 1 year. Of the cases, 73.3% were a recurrent disease. Microscopic tumor resection was achieved in all but one case (93.3%). Seven cases had no complications (46.7%). Surgical complications were classified according to the Clavien-Dindo system (grades I n = 2; II n = 2; IIIb n = 4). These were mainly wound healing disorders that did not affect mobilization or discharge. The time to discharge was 22 + 9.9 days. The oncological outcomes were as follows: 53.3% of the patients had no evidence of disease, 20% had metastatic disease, 20% had local recurrent disease, and one patient (6.7%) died of other causes. CONCLUSIONS: The GFF is a robust, reliable flap suitable for perineal and pelvic reconstruction. It can be raised quickly and easily, has an acceptable complication rate and donor site morbidity, and does not affect the abdominal wall.

Levels of activated platelet-derived microvesicles in patients with soft tissue sarcoma correlate with an increased risk of venous thromboembolism.

BACKGROUND: Microvesicles are small vesicles expressing specific antigens from their cells of origin. Elevated levels of microvesicles have been shown to be associated with coagulation disorders as well as with different types of malignancies. This study aims to evaluate a possible correlation of different microvesicle subpopulations with a positive history of venous thromboembolism (VTE) in patients with soft tissue sarcoma. METHODS: Annexin V - positive microvesicles, leukocyte (CD45-positive), platelet (CD61-positive), activated platelet (CD62P-, CD63-positive), endothelium-derived (CD62E-positive) and tissue-factor (CD142-positive) microvesicles were identified in the peripheral blood of patients with soft tissue sarcoma (n = 39) and healthy controls (n = 17) using fluorescence-activated cell sorting (FACS). RESULTS: Both the total amount of Annexin V-positive microvesicles and levels of endothelium-derived (CD62E-positive) microvesicles were shown to decrease significantly after tumor resection (n = 18, p = 0.0395 and p = 0.0109, respectively). Furthermore, the total amount of Annexin V - positive microvesicles as well as leukocyte (CD45-positive) and endothelium-derived (CD62E-positive) microvesicles were significantly higher in patients with grade 3 (G3) soft tissue sarcoma (n = 9) compared to healthy controls (n = 17) (p = 0.0304, p = 0.0254 and p = 0.0357, respectively). Moreover, patients with G3 soft tissue sarcoma (n = 9) presented higher levels of Annexin V-positive and endothelium-derived (CD62E-positive) microvesicles compared to patients with grade 2 (G2) soft tissue sarcoma (n = 8) (p = 0.0483 and p = 0.0045). Patients with grade 1 (G1) soft tissue sarcoma (n = 3) presented with significantly lower levels of platelet (CD61-positive) microvesicles than patients with G3 soft tissue sarcoma (n = 9) (p = 0.0150). In patients with a positive history of VTE (n = 11), significantly higher levels of activated platelet (CD62P- and CD63-positive) microvesicles (p = 0.0078 and p = 0.0450, respectively) were found compared to patients without a history of VTE (n = 28). CONCLUSION: We found significantly higher levels of Annexin V-positive and endothelium-derived (CD62E-positive) microvesicles to be circulating in the peripheral blood of patients with G3 soft tissue sarcoma compared to patients with G2 soft tissue sarcoma. Furthermore, we showed that high counts of activated platelet-derived microvesicles correlate with the occurrence of VTE. Thus, the detection of these microvesicles might be an interesting new tool for early diagnosis of soft tissue sarcoma patients with increased risk for VTE, possibly facilitating VTE prevention by earlier use of thromboprophylaxis.

Long-Term Follow-up of Recurrence and Patient Satisfaction After Surgical Treatment of Gynecomastia.

BACKGROUND: "Gynecomastia" is an enlargement of the male breast. Our study aims to assess patient satisfaction as well as evaluate differences in recurrence rates in lipomatous and glandular gynecomastia 10-19 years postoperatively. METHODS: Forty-one gynecomastia patients undergoing surgical treatment from 1997 to 2005 were invited for a follow-up examination 10-19 years postoperatively. Of these, 16 patients presented for a clinical examination. Patient satisfaction was measured with a validated questionnaire [consultation satisfaction questionnaire (CSQ)-9]. Furthermore, photo-material and patient charts were evaluated concerning preoperative macroscopical type of gynecomastia, BMI, and operative technique. RESULTS: Mean follow-up time was 13.8 years (range: 10.5-19 years). Eight patients (50%) had presented with lipomatous and eight patients (50%) with glandular gynecomastia prior to surgery. One of the patients with glandular gynecomastia (12.5%) presented with recurrence at the time of follow-up, while five of the eight patients showing lipomatous gynecomastia (62.5%) presented with recurrence. Interestingly, younger patient groups tend to be more satisfied with the operative treatment of gynecomastia than older patient groups, especially regarding the improvement of self-esteem. CONCLUSIONS: Long-term follow-up results showed that recurrence rates are significantly higher in patients with lipomatous gynecomastia than in patients with glandular gynecomastia, with BMI increase in patients with glandular and lipomatous gynecomastia showing no statistically significant differences. Furthermore, general patient satisfaction and improvement of self-esteem was higher in younger patient groups than older patient groups. LEVEL OF EVIDENCE IV: 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 . CLINICAL TRIAL REGISTRATION NUMBER: DRKS00009630.

Overexpression of Hif-1α in Mesenchymal Stem Cells Affects Cell-Autonomous Angiogenic and Osteogenic Parameters.

Reconstruction of large bone defects still represents a major medical challenge. In recent years tissue engineering has developed techniques based on adult mesenchymal stem cells (MSCs) that could represent an attractive therapeutical option to treat large bone defects in the future. It has been demonstrated in various animal models that ex vivo expanded MSCs are capable of promoting the regeneration of skeletal defects after implantation. However, for the efficient regeneration of bone in tissue engineering applications, a rapid vascularization of implanted grafts is essential to ensure the survival of cells in the early post-implantational phase. A promising strategy to enhance vascularization of MSC-containing implants could consist of overexpression of the angiogenic master transcription factor Hypoxia-inducible factor 1 (Hif-1) in the MSCs in order to induce angiogenesis and support osteogenesis. In the present study, we overexpressed Hif-1α in MSCs by using recombinant adenoviruses and investigated cell-autonomous effects. Overexpression of Hif-1α enhanced proliferation, migration, cell survival and expression of pro-angiogenic genes. Other parameters such as expression of the osteogenic markers BMP-2 and RunX2 were decreased. Hif-1α overexpression had no effect on invasion, senescence and osteogenic differentiation of MSCs. Our experiments revealed multifarious effects of Hif-1α overexpression on cell-autonomous parameters. Therefore, Hif-1α overexpression may represent a therapeutic option to improve cellular functions of MSCs to treat critical sized bone defects.

Adipose-Derived Stem Cells Support Lymphangiogenic Parameters In Vitro.

It is a common complication to develop a secondary lymphedema after surgery or radiation, for example, after axillary lymph node dissection due to breast cancer and current therapies are mainly symptomatic. Since these surgical procedures result in both, loss of adipose tissue and loss of lymphatic nodes and vessels, tissue engineering could be a new promising approach, to create an adipose tissue substitute comprised with a lymphatic network. We have conducted co-culture experiments to investigate the effects of human adipose-derived stem cells (ASCs) on human lymphatic endothelial cells (LECs) in terms of gene expression profile, proliferation, migration, and tube formation in vitro. In this respect, both cell types were co-cultured either indirectly or directly with or without the recombinant growth factor VEGF-C. Indirect co-cultures were performed with the aid of a transwell chamber. In case of direct co-culture, immunomagnetic separation by CD31 magnetic beads allowed examination of the LEC population. Direct and indirect co-culture of ASCs induced mRNA expression of lymphatic marker genes, proliferation, and migration by LECs without affecting tube formation. Thus, we have shown that co-culture of ASCs with LECs might be a feasible approach that could be used in cell-based tissue engineering therapies to heal or improve a secondary lymphedema. J. Cell. Biochem. 117: 2620-2629, 2016. © 2016 Wiley Periodicals, Inc.

Targeting C-Reactive Protein in Inflammatory Disease by Preventing Conformational Changes.

C-reactive protein (CRP) is a pentraxin that has long been employed as a marker of inflammation in clinical practice. Recent findings brought up the idea of CRP to be not only a systemic marker but also a mediator of inflammation. New studies focused on structural changes of the plasma protein, revealing the existence of two distinct protein conformations associated with opposed inflammatory properties. Native, pentameric CRP (pCRP) is considered to be the circulating precursor form of monomeric CRP (mCRP) that has been identified to be strongly proinflammatory. Recently, a dissociation mechanism of pCRP has been identified on activated platelets and activated/apoptotic cells associated with the amplification of the proinflammatory potential. Correspondingly, CRP deposits found in inflamed tissues have been identified to exhibit the monomeric conformation by using conformation-specific antibodies. Here we review the current literature on the causal role of the dissociation mechanism of pCRP and the genesis of mCRP for the amplification of the proinflammatory potential in inflammatory reactions such as atherosclerosis and ischemia/reperfusion injury. The chance to prevent the formation of proinflammatory mediators in ubiquitous inflammatory cascades has pushed therapeutic strategies by targeting pCRP dissociation in inflammation. In this respect, the development of clinically applicable derivatives of the palindromic compound 1,6-bis(phosphocholine)-hexane (1,6-bis PC) should be a major focus of future CRP research.

Increased extracellular matrix and proangiogenic factor transcription in endothelial cells after cocultivation with primary human osteoblasts.

The most promising strategies in bone engineering have concentrated on providing sufficient vascularization to support the newly forming tissue. In this context, recent research in the field has focused on studying the complex interactions between bone forming and endothelial cells. Our previous work has demonstrated that direct contact cocultivation of human umbilical vein endothelial cells (HUVECs) with primary human osteoblasts (hOBs) induces the osteogenic phenotype and survival of hOBs. In order to investigate the mechanisms that lead to this effect, we performed microarray gene expression profiling on HUVECs following cocultivation with hOBs. Our data reveal profound transcriptomic changes that are dependent on direct cell contact between these cell populations. Pathway analysis using the MetaCore™ platform and literature research suggested a striking upregulation of transcripts related to extracellular matrix and cell-matrix interactions. Upregulation of a number of major angiogenetic factors confirms previous observations that HUVECs enter a proangiogenic state upon cocultivation with osteoblasts. Interestingly, the downregulated transcripts clustered predominantly around cell cycle-related processes. The microarray data were confirmed by quantitative real-time RT-PCR on selected genes. Taken together, this study provides a platform for further inquiries in complex interactions between endothelial cells and osteoblasts.

Effects of bone morphogenetic protein 2 on human umbilical vein endothelial cells.

Bone morphogenetic proteins (BMPs) and their receptors play important roles in cellular processes such as proliferation, differentiation, migration and cell survival. It was also demonstrated that BMPs are involved in vasculogenesis and angiogenesis. In this study, we investigated the expression profile of BMP receptors in human umbilical vein endothelial cells (HUVECs) and determined the effect of BMP-2 on proliferation, migration, invasion, cell survival and tube formation. HUVECs express the type I BMP receptors ALK2, ALK3 and ALK6 and the type II receptor BMPR-II. Treatment of HUVECs with recombinant human BMP-2 induced migration, invasion and tube formation of HUVECs without affecting proliferation and apoptosis. Our data suggest that BMP-2 represents a chemoattractant and proangiogenic factor for HUVECs.

Accuracy of core needle biopsy for histologic diagnosis of soft tissue sarcoma.

The biopsy technique of choice in soft tissue sarcoma (STS) diagnosis is controversial. We examined the diagnostic accuracy of percutaneous core needle biopsy (CNB) and compared it to open incisional biopsy. A retrospective study included 91 incisional biopsies and 102 CNBs. A pair-match investigation was conducted on 19 patient pairs, comparing sensitivity, specificity, and diagnostic accuracy. Furthermore, we investigated the role of molecular pathology in sarcoma diagnostics. In 81/91 (89%) patients with incisional biopsy, the entity was confirmed by definitive pathology, whereas this was the case in 89/102 (87%) CNB patients (p = 0.52). Grading remained unchanged in 46/55 (84%) of incisional and 54/62 (87%) of CNBs (p = 0.61). The pair matched analysis showed that the correct entity was determined in 96% of incisional and 97.6% of core needle biopsies. The time between the initial consultation and the interdisciplinary tumor board's treatment recommendation was shorter in core needle biopsies (8.37 vs. 15.63 days; p < 0.002). Incisional biopsies led to two wound infections and one hematoma, whereas wound infection occurred in one patient after CNB. CNB leads to faster diagnosis while reaching the same histological accuracy and is less burdensome for patients. Still, surgeons need to remain aware of the possibility of biopsy failure.

The Edmonton Obesity Staging System as a predictor for postoperative complications after medial thigh lift in massive weight loss patients.

BACKGROUND: This study investigates the correlation between the Edmonton Obesity Staging System (EOSS) and the occurrence of postoperative complications after medial thigh lift in formerly obese patients. PATIENTS AND METHODS: A single-institution retrospective review of patients undergoing medial thigh lift between 2009 and 2019 after massive weight loss. Data on demography, comorbidities, surgery, and postoperative outcome were extracted from patients' charts. Patients were grouped into EOSS categories. Complications were classified into minor and major. Logistic regression analysis was performed to determine the association between risk factors and complications. RESULTS: One hundred and eight patients were included in the study. Complications occurred in 76 (70%) of the patients, most of which were minor (60/108, 56%). Complications increased with increasing EOSS stage, and all EOSS 3 patients had complications. Classification as EOSS 2 or 3 significantly associated with occurrence of postoperative complications (OR 99.3, p<0.001) as well as minor and major complications individually (OR 3.1 and 6.5, p<0.05). This effect was independent of body mass index (BMI), maximum BMI loss, type of weight loss, volume of liposuction, weight of resected tissue, and type of surgery. CONCLUSION: EOSS is a robust and independent predictor for postoperative complications in medial thigh lift surgery after massive weight loss.

[Registry Research Funding of the German Society of Plastic, Reconstructive and Aesthetic Surgeons (DGPRÄC) and Research Funding Report 2019/2020]. / Register Forschungsförderung der Deutschen Gesellschaft der Plastischen, Rekonstruktiven und Ästhetischen Chirurgen (DGPRÄC) und Forschungsförderungsbericht 2019/2020.

BACKGROUND: Since 2015/16 the DGPRÄC collects, evaluates and publishes the research activities of academic sections, departments and clinics for plastic surgery at university hospitals in Germany, in order to raise the awareness of plastic surgical research performance. MATERIALS AND METHODS: The directors of plastic surgical academic institutions were contacted via the DGPRÄC and asked to report any requested/approved and rejected research applications to public, non-public and industrial funding organizations. Data was collected in our previously established online database: https://docs.google.com/forms/d/e/1FAIpQLSe6F5xmTyw-k7VKJx_2jkPA4LBXsA0sgBGMrC3rx_4bHj6uzQ/viewform?usp=sf_link. In addition, applications were identified via the DFG's public database GEPRIS. RESULTS: A total of 41 funding applications to the public funding institutes DFG, BMBF, BMWi, BMG and EU were identified. 75.6 % (31/41) of the applications had already been approved at the time of data collection, of which 77.4 % (24/31) were DFG, 9.7 % (3/31) were BMWi, 6.5 % (2/31) were EU and 3.2 % (1/31) were BMBF or BMG applications. The average funding amounted to 358 301 Euro. In 50.0 % (12/24) of the cases, the approved DFG proposals were assigned to the subject review board 205-27 Orthopedics, Trauma Surgery, Reconstructive Surgery. CONCLUSION: The continuous publication of plastic surgical research funding reports submitted by the convention of university plastic surgeons of the DGPRÄC portraits the excellent, collaborative research activity in the field of plastic surgery.

Comparison of pre-adipocyte yield, growth and differentiation characteristics from excised versus aspirated adipose tissue.

Adipose tissue precursor cells (pre-adipocytes) are part of a stromal vascular fraction that can be easily isolated from fat tissue. Adipose tissue can be harvested by 2 methods: aspiration and excision. We analyzed whether the pre-adipocyte yield, growth characteristics and ability to differentiate into mature adipose tissue are influenced by the type of harvesting procedure. Adipose tissue was simultaneously harvested from the abdomen by surgical excision or aspiration according to the Coleman procedure in 10 individuals. This permitted inter- and intra-individual comparisons. Cell viability and yield were determined directly after isolation of pre-adipocytes. The growth kinetics were investigated in culture. Furthermore, pre-adipocytes were cultured under adipogenic conditions to compare their differentiation potential. The number of viable pre-adipocytes was significantly higher after excision of adipose tissue compared to aspiration. The proliferation kinetic was not influenced by the type of harvesting. No differences were observed in the differentiation potential of the pre-adipocytes between both groups. Compared to excision, aspiration of adipose tissue negatively affects the yield of pre-adipocytes. However, growth characteristics and differentiation potential of viable cultured cells are not influenced by the type of surgical harvesting. Due to its reduced donor site morbidity, we conclude that aspiration of adipose tissue is a valid harvesting method for isolation of pre-adipocytes.

Reconstruction of Perineal Defects: A Comparison of the Myocutaneous Gracilis and the Gluteal Fold Flap in Interdisciplinary Anorectal Tumor Resection.

Introduction: Resection of anorectal malignancies may result in extensive perineal/pelvic defects that require an interdisciplinary surgical approach involving reconstructive surgery. The myocutaneous gracilis flap (MGF) and the gluteal fold flap (GFF) are common options for defect coverage in this area. Here we report our experience with the MGF/GFF and compare the outcome regarding clinical key parameters. Methods: In a retrospective chart review, we collected data from the Department of Plastic Surgery of the University of Freiburg from December 2008-18 focusing on epidemiological, oncological, and therapy-related data including comorbidities (ASA Classification) and peri-/postoperative complications (Clavien-Dindo-System). Results: Twenty-nine patients were included with a mean follow-up of 17 months. Of the cases, 19 (65.5%) presented with recurrent disease, 21 (72.4%) received radiochemotherapy preoperatively, 2 (6.9%) received chemotherapy alone. Microscopic tumor free margins were achieved in 25 cases (86.2%). 17 patients (7 men, 10 women, rectal adenocarcinoma n = 11; anal squamous cell carcinoma n = 6; mean age 58.5 ± 10.68, mean BMI 23.1, mean ASA score 2.8) received a MGF (unilateral n = 10; bilateral n = 7). Twelve patients (7 men, 5 women, rectal adenocarcinoma n = 7; anal squamous cell carcinoma n = 4, proctodeal gland carcinoma n = 1, mean age 66.2 ± 9.2, mean BMI 23.6, mean ASA score 2.6) received coverage with a GFF (unilateral n = 4; bilateral n = 8). Mean operation time of coverage was 105 ± 9 min for unilateral and 163 ± 11 for bilateral MGFs, 70 ± 13 min for unilateral and 107 ± 14 for bilateral GFFs. Complications affected 62%. There was no significant difference in the complication rate between the MGF- and GFF-group. Complications were mainly wound healing disorders that did not extend the hospital stay. No flap loss and no complication that lead to long-lasting disability was documented (both groups). Pain-free sitting took more time in the GFF-group due to the location of the donor site. Conclusion: MG-flaps and GF-flaps prove to be reliable and robust techniques for perineal/pelvic reconstruction. Though flap elevation is significantly faster for GF-flaps, preoperative planning and intraoperative Doppler confirmation are advisable. With comparable complication rates, we suggest a decision-making based on distribution of adipose tissue for dead space obliteration, intraoperative patient positioning, and perforator vessel quality/distribution.

Epidermal growth factor (EGF) transfection of human bone marrow stromal cells in bone tissue engineering.

A novel therapeutic approach for the treatment of bone defects is gene therapy assisted bone tissue engineering using bone marrow stromal cells (hBMSC). The aim of this study was to investigate the influence of human epidermal growth factor (hEGF) on proliferation and alkaline phosphatase (AP) activity of primary hBMSC in vitro. hBMSC cultures were achieved by explantation culture of bone chips. Following exposure to 0-10 ng recombinant hEGF (rhEGF)/ml cell numbers were determined by automated cell counting and cell bound AP activity was measured spectrophotometrically. hBMSC were transfected with hEGF plasmids and the proliferative effect was studied by cocultivation of transfected and untreated cells using porous cell culture inserts. The persistence of hEGF expression even after cell transfer was studied by the generation of possibly osteogenic constructs introducing transfected hBMSC in fibrin glue and bovine cancellous bone. The maximum increase in proliferation (156 +/- 7%) and AP activity (220 +/- 34%) was detected after exposition to 10 ng rhEGF/ml. In the separation chamber assay transfected cells produced hEGF concentrations up to 3.6 ng/ml, which induced a mean proliferation increase of 93% which could be significantly inhibited by a neutralizing hEGF antibody. Further, EGFsecretion of transfected hBMSC in 3D-culture was verified. Recombinant and transgenic hEGF stimulate proliferation of primary hBMSC in vitro. Lipotransfection of hBMSC with hEGF plasmids allows the transient and site directed delivery of biologically active transgenic hEGF. The introduction of mitogenic, angiogenic and chemoattractive factors in gene therapy assisted bone tissue engineering is discussed by the example of EGF.

Efficacy and Safety of Microsurgery in Interdisciplinary Treatment of Sarcoma Affecting the Bone.

Background: Sarcomas are tumors of mesenchymal origin with high variation in anatomical localization. Sarcomas affecting the bone often require an interdisciplinary resection and reconstruction approach. However, it is critical that microsurgical reconstruction strategies do not negatively impact tumor safety and overall survival, as limb salvage is only the secondary goal of tumor surgery. Here, we analyzed the efficacy and safety of microsurgery in interdisciplinary treatment of sarcoma affecting the bone. Patients and Methods: We performed a retrospective chart review of all patients treated for soft-tissue and bone sarcoma at the senior author's institution with a focus on bone affection and microsurgical reconstruction between 2000 and 2019. This particular subgroup was further investigated for tumor resection status, 5-year survival rate, length of hospital stay, as well as overall complication and amputation rates. Results: Between 2000 and 2019, 803 patients were operated for sarcoma resection and reconstruction by the Department of Plastic and Hand Surgery. Of these, 212 patients presented with sarcoma of the extremity affecting the bone. Within this subgroup, 40 patients required microsurgical reconstruction for limb salvage, which was possible in 38 cases. R0 resection was achieved in 93.8%. The 5-year survival was 96.7%, and the overall complication rate was 25%, of which 40% were microsurgery associated complications. Conclusion: Safe and function-preserving treatment of soft-tissue and bone sarcoma is challenging. Primary reconstruction with microsurgical techniques of sarcoma-related defects enables limb-sparing and adequate oncosurgical cancer treatment without increasing the risk for local recurrence or prolonged hospital stay. The treatment of sarcoma patients should be reserved to high-volume centers with experienced plastic surgeon embedded in a comprehensive treatment concept.