Preadipocytes in human granulation tissue: role in wound healing and response to macrophage polarization

BACKGROUND

Chronic non-healing wounds pose a global health challenge. Under optimized conditions, skin wounds heal by the formation of scar tissue. However, deregulated cell activation leads to persistent inflammation and the formation of granulation tissue, a type of premature scar tissue without epithelialization. Regenerative cells from the wound periphery contribute to the healing process, but little is known about their cellular fate in an inflammatory, macrophage-dominated wound microenvironment.

METHODS

We examined CD45-/CD31-/CD34+ preadipocytes and CD68+ macrophages in human granulation tissue from pressure ulcers (n=6) using immunofluorescence, immunohistochemistry, and flow cytometry. In vitro, we studied macrophage-preadipocyte interactions using primary human adipose-derived stem cells (ASCs) exposed to conditioned medium harvested from IFNG/LPS (M1)- or IL4/IL13 (M2)-activated macrophages. Macrophages were derived from THP1 cells or CD14+ monocytes. In addition to confocal microscopy and flow cytometry, ASCs were analyzed for metabolic (OXPHOS, glycolysis), morphological (cytoskeleton), and mitochondrial (ATP production, membrane potential) changes. Angiogenic properties of ASCs were determined by HUVEC-based angiogenesis assay. Protein and mRNA levels were assessed by immunoblotting and quantitative RT-PCR.

RESULTS

CD45-/CD31-/CD34+ preadipocytes were observed with a prevalence of up to 1.5% of total viable cells in human granulation tissue. Immunofluorescence staining suggested a spatial proximity of these cells to CD68+ macrophages in vivo. In vitro, ASCs exposed to M1, but not to M2 macrophage secretome showed a pro-fibrotic response characterized by stress fiber formation, elevated alpha smooth muscle actin (SMA), and increased expression of integrins ITGA5 and ITGAV. Macrophage-secreted IL1B and TGFB1 mediated this response via the PI3K/AKT and p38-MAPK pathways. In addition, ASCs exposed to M1-inflammatory stress demonstrated reduced migration, switched to a glycolysis-dominated metabolism with reduced ATP production, and increased levels of inflammatory cytokines such as IL1B, IL8, and MCP1. Notably, M1 but not M2 macrophages enhanced the angiogenic potential of ASCs.

CONCLUSION

Preadipocyte fate in wound tissue is influenced by macrophage polarization. Pro-inflammatory M1 macrophages induce a pro-fibrotic response in ASCs through IL1B and TGFB1 signaling, while anti-inflammatory M2 macrophages have limited effects. These findings shed light on cellular interactions in chronic wounds and provide important information for the potential therapeutic use of ASCs in human wound healing.

Delayed Reconstruction after Major Head and Neck Cancer Resection: An Interdisciplinary Feasibility Study

A single immediate reconstruction with free tissue transfer is the method of choice after major head and neck cancer (HNC) resection, but this is frequently associated with long operating hours. Considering regulatory working hour constraints, we investigated whether a two-staged reconstructive approach with temporary defect coverage by an artificial tissue substitute would be feasible. HNC patients underwent either immediate or delayed reconstruction after tumor resection. Patients with delayed reconstruction received preliminary reconstruction with an artificial tissue substitute followed by definitive microvascular reconstruction in a separate, second procedure. Of the 33 HNC patients, 13 received delayed reconstruction and 20 received immediate reconstruction. Total anesthesia time (714 vs. 1011 min; p < 0.002) and the total duration of hospital stay (34 ± 13 vs. 25 ± 6 days; p = 0.03) were longer in the delayed reconstruction group. Perioperative morbidity (p = 0.58), functional outcome (p > 0.1) and 5-year postoperative survival rank (p = 0.28) were comparable in both groups. Delayed reconstruction after HNC resection was feasible. Perioperative morbidity, functional outcome and overall survival were comparable to immediate reconstruction.

Resection of Skin Cancer Resulting in Free Vascularized Tissue Reconstruction: Always a Therapeutic Failure?

The globally increasing incidence of cutaneous malignancies leads, in parallel, to increasing numbers of locally advanced skin cancer resulting in reconstructive surgery. Reasons for locally advanced skin cancer may be a patient's neglect or aggressive tumor growth, such as desmoplastic growth or perineural invasion. This study investigates characteristics of cutaneous malignancies requiring microsurgical reconstruction with the aim of identifying possible pitfalls and improving diagnostic and therapeutic processes. A retrospective data analysis from 2015 to 2020 was conducted. Seventeen patients (n = 17) were included. The mean age at reconstructive surgery was 68.5 (±13) years. The majority of patients (14/17, 82%) presented with recurrent skin cancer. The most common histological entity was squamous cell carcinoma (10/17, 59%). All neoplasms showed at least one of the following histopathological characteristics: desmoplastic growth (12/17, 71%), perineural invasion (6/17, 35%), or tumor thickness of at least 6 mm (9/17, 53%). The mean number of surgical resections until cancer-free resection margins (R0) were achieved was 2.4 (±0.7). The local recurrence rate and the rate of distant metastases were 36%. Identified high-risk neoplastic characteristics, such as desmoplastic growth, perineural invasion, and a tumor depth of at least 6 mm, require a more extensive surgical treatment without concerns about defect size.

Depletion of growth differentiation factor 15 (GDF15) leads to mitochondrial dysfunction and premature senescence in human dermal fibroblasts

Growth differentiation factor 15 (GDF15) is a stress-responsive cytokine also known as a mitokine; however, its role in mitochondrial homeostasis and cellular senescence remained elusive. We show here that knocking down GDF15 expression in human dermal fibroblasts induced mitochondrial dysfunction and premature senescence, associated with a distinct senescence-associated secretory phenotype. Fibroblast-specific loss of GDF15 expression in a model of 3D reconstructed human skin induced epidermal thinning, a hallmark of skin aging. Our results suggest GDF15 to play a so far undisclosed role in mitochondrial homeostasis to delay both the onset of cellular senescence and the appearance of age-related changes in a 3D human skin model.

Dipeptidyl peptidase-4 cell surface expression marks an abundant adipose stem/progenitor cell population with high stemness in human white adipose tissue

The capacity of adipose stem/progenitor cells (ASCs) to undergo self-renewal and differentiation is crucial for adipose tissue homoeostasis, regeneration and expansion. However, the heterogeneous ASC populations of the adipose lineage constituting adipose tissue are not precisely known. In the present study, we demonstrate that cell surface expression of dipeptidyl peptidase-4 (DPP4)/cluster of differentiation 26 (CD26) subdivides the DLK1^-/CD34⁺/CD45^-/CD31^- ASC pool of human white adipose tissues (WATs) into two large populations. Ex vivo, DPP4⁺ ASCs possess higher self-renewal and proliferation capacity and lesser adipocyte differentiation potential than DDP4^- ASCs. The knock-down of DPP4 in ASC leads to significantly reduced proliferation and self-renewal capacity, while adipogenic differentiation is increased. Ectopic overexpression of DPP4 strongly inhibits adipogenesis. Moreover, in whole mount stainings of human subcutaneous (s)WAT, we detect DPP4 in CD34⁺ ASC located in the vascular stroma surrounding small blood vessels and in mature adipocytes. We conclude that DPP4 is a functional marker for an abundant ASC population in human WAT with high proliferation and self-renewal potential and low adipogenic differentiation capacity.

An organoid model derived from human adipose stem/progenitor cells to study adipose tissue physiology

We established a functional adipose organoid model system for human adipose stem/progenitor cells (ASCs) isolated from white adipose tissue (WAT). ASCs were forced to self-aggregate by a hanging-drop technique. Afterwards, spheroids were transferred into agar-coated cell culture dishes to avoid plastic-adherence and dis-aggregation. Adipocyte differentiation was induced by an adipogenic hormone cocktail. Morphometric analysis revealed a significant increase in organoid size in the course of adipogenesis until d 18. Whole mount staining of organoids using specific lipophilic dyes showed large multi- and unilocular fat deposits in differentiated cells indicating highly efficient differentiation of ASCs into mature adipocytes. Moreover, we found a strong induction of the expression of key adipogenesis and adipocyte markers (CCAAT/enhancer-binding protein (C/EBP) β, peroxisome proliferator-activated receptor (PPAR) γ, fatty acid-binding protein 4 (FABP4), adiponectin) during adipose organoid formation. Secreted adiponectin was detected in the cell culture supernatant, underscoring the physiological relevance of mature adipocytes in the organoid model. Moreover, colony formation assays of collagenase-digested organoids revealed the maintenance of a significant fraction of ASCs within newly formed organoids. In conclusion, we provide a reliable and highly efficient WAT organoid model, which enables accurate analysis of cellular and molecular markers of adipogenic differentiation and adipocyte physiology.

Does the breast reconstruction method have an impact on time delay to adjuvant chemotherapy – A comparison between autologous and expander/implant breast reconstruction

Introduction

This study aims to analyze whether autologous breast reconstruction as compared to expander/implant reconstruction has a higher risk of postoperative wound healing problems (WHPs) and thus potentially delays chemotherapy start.

Methods

Between January 2012 and December 2019, a total of 64 women with NSME/SSME and autologous (Group1, n = 33) or expander/implant reconstruction (Group2, n = 31) and adjuvant chemotherapy were enrolled in this study conducted at Innsbruck Medical University Hospital. Immediate postoperative WHPs in each group were compared, and the time from operation to initiation of chemotherapy was analyzed. If the start of chemotherapy was postponed for more than six weeks postoperatively due to WHP, it was defined as delayed. Statistical analysis was performed with SPSS and Fisher's exact test.

Results

More postoperative WHP occurred in Group 1 than in Group 2 (51.6% vs. 9.7%, p < 0.001). Due to WHP, chemotherapy start was delayed for more than six weeks postoperatively in 30.3% of Group 1 patients and 3.2% of Group 2 patients. Only small differences in age (Group 1: 47±1 vs. Group 2: 46±2 years) and BMI (Group 1: 24.3 ± 0.6 vs. Group 2: 23.3 ± 0.7 kg/m²) were found.

Conclusion

Our study shows a far smaller risk for postoperative WHP and delay of chemotherapy start in the expander/implant group in comparison with the autologous group. In some selected patients with high urgency for adjuvant chemotherapy, a bridging operation by means of expander reconstruction prior to chemotherapy could be an oncologically safe pathway.

Correction of temporal hollowing after pterional craniotomy by autologous fat grafting. A single-center experience

OBJECTIVE

Aesthetic complications following neurosurgical procedures impact patient quality of life and self-perception. Postoperative temporal hollowing is frequently seen after temporal craniotomy, resulting mainly from atrophy of the temporal muscle. Autologous fat grafting is a tailorable method to correct such approach-related sequelae. We herein present our clinical patient series and discuss pearls and pitfalls of this method.

METHODS

In this retrospective single-center study, correction of postoperative temporal hollowing using autologous fat grafting was performed in 16 patients. Temporal tissue thickness ratio was measured using magnetic resonance tomography images to visualize the graft. Patients, plastic surgeons and neurosurgeons evaluated the results independently using the herein presented scale.

RESULTS

The mean interval between the neurosurgical procedure and fat grafting was 62 months. A mean volume of 11.5 ml autologous fat was injected in an average of 2.5 sessions after initial rigotomy. Temporal tissue thickness was significantly augmented at a mean of 2.2 years after the operation (mean 0.71 ± 0.25, range 0.43-1.1; p=0.0214) as compared to the preoperative finding (mean 0.48 ± 0.1, range 0.32-0.6). Patients were more satisfied with the results than were surgeons, reflecting the significant impact of the deformity on patient self-esteem.

CONCLUSIONS

Autologous fat grafting is a valuable method for correcting postoperative temporal hollowing that provides stable results, high patient and surgeon satisfaction and can be tailored to the patient's individual needs. It should not be considered a merely aesthetic operation, but an important rehabilitation step towards restoring the patient's quality of life.

Hide-and-seek: Neurotropic squamous cell carcinoma of the periorbital region - a series of five cases and review of the literature

Squamous cell carcinoma is the second most common malignancy of the skin after basal cell carcinoma and mainly found in sun‐exposed areas such as the face. This mostly locally destructive malignancy may show invasive growth and insidious mechanisms of dissemination such as perineural invasion. Periorbital squamous cell carcinoma is associated with perineural invasion in up to 14 % of cases. Specifically in this region, the proximity to cranial nerves and therefore the associated risk of progression to the central nervous system are associated with poor prognosis. The clinically concealed character of this entity often leads to a delay in diagnosis and consequently makes complete resection and reconstruction demanding. Careful clinical evaluation often hints at perineural invasion before obtaining histology.

Aside from presenting five challenging cases, this work analyzes risk factors, clinical as well as histological features, and treatment options for periorbital squamous cell carcinoma with perineural invasion.

Hide-and-seek: Neurotropes Plattenepithelkarzinom der periorbitalen Region - eine Fallserie und Übersichtsarbeit aktueller Literatur

Das Plattenepithelkarzinom ist nach dem Basalzellkarzinom das zweithäufigste Malignom der Haut und wird vorwiegend an sonnenexponierten Stellen wie der Gesichtshaut diagnostiziert. Diese meist lokal destruktiv wachsende Malignität kann durchaus auch invasives Wachstumsverhalten, wie perineurale Ausbreitungsmechanismen, aufweisen. Das Plattenepithelkarzinom der periorbitalen Region ist in bis zu 14 % der Fälle mit perineuraler Invasion assoziiert. Vor allem in diesem Bereich birgt die anatomische Nähe zu den Hirnnerven das Risiko einer Progression Richtung zentrales Nervensystem, was mit einer schlechteren Prognose assoziiert ist. Der klinisch unauffällige Charakter dieser Entität resultiert oft in einer Verzögerung der definitiven Diagnosestellung, wodurch die vollständige Resektion und anschließende Rekonstruktion erschwert werden. Eine aufmerksame klinische Evaluierung kann bereits vor Erlangen histologischer Befunde Hinweise für ein perineurales Wachstum liefern. Neben fünf herausfordernden Fällen analysiert diese Arbeit Risikofaktoren, klinische als auch histologische Merkmale und Behandlungsoptionen des periorbitalen Plattenepithelkarzinoms mit perineuraler Invasion.

Ski- and snowboard related open peroneal nerve injury: A 20-year retrospective case series study

Introduction

Traumatic peroneal nerve injury (PNI) caused by ski or snowboard edges is a severe but scarcely reported accident.

Methods

In a 20-year retrospective study, all skiers and snowboarders with this injury treated surgically at the Department of Plastic, Reconstructive and Aesthetic Surgery at the Medical University of Innsbruck, Austria, were included, covering a period from 1999/2000 to 2018/2019.

Results

In total, 34 patients were included in this study (30 males (88.2%) and 4 (11.8%) females). Of these 34 injured skiers or snowboarders, 33 (97.1%) were recreational athletes and Non-Austrian citizens, and 21 (61.8%) patients sustained accidental injuries without collision. All of the injuries under investigation, i.e., open lacerations, most often with complete transection, were the patients’ main injuries. Surgery was performed with direct coaptation in 24 patients (70.6%), and with a suralis nerve graft in the other 10 patients (29.4%).

Conclusion

Traumatic laceration of the peroneal nerve at the knee level by sharp ski or snowboard edges is a rare but severe injury. Causes for this injury may be multifactorial. Recommendations to reduce the risk of such an injury may follow general instructions and warnings to skiers and snowboarders regarding equipment, familiarity with the region, as well as appropriate skills and training.

•

In accidents of skiers and snowboarders traumatic laceration of the peroneal nerve is a severe, but rare injury.

•

This injury type is rarely reported.

•

The injuries are caused by the sharp edges of modern skies or snowboards and require urgent microsurgical intervention.

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Our 20 years study shows that this injury type primarily affects recreational athletes and guest skiers.

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Current equipment, e.g. ski trousers do not protect the affected region on the lateral side of the knee.

Simple, but effective: Nasal splinting for airway securement in free flap reconstruction following orbital exenteration

Orbital exenteration is a disfiguring procedure that often results in free tissue transfer for reconstructive purposes. The reconstructive focus is the obliteration of dead space while sparing the nasal airway, particularly if the medial orbital wall was resected. Prolapse of transferred tissue into the nasal airway may cause breathing difficulties drastically compromising quality of life. The objective of this study was to demonstrate the effectiveness and feasibility of temporary nasal septum splints as mechanical support for transferred tissue, to prevent airway obstruction. This novel application technique was employed in three patients between 2017 and 2018. No flap loss or sino‐orbital fistulas were observed. On postoperative MRI and endoscopy, a patent nasal airway was observed at all times. Temporary nasal splinting in combination with free tissue transfer proved to be a simple, but effective reconstructive option for securing the nasal airway following orbital exenteration with resection of the medial orbital wall.

Oxidant therapy improves adipogenic differentiation of adipose-derived stem cells in human wound healing

Background

Adipose-derived stem cells (ASC) and adipocytes are involved in numerous physiological and pathophysiological conditions, which have been extensively described in subcutaneous and visceral fat depots over the past two decades. However, much less is known about ASC and adipocytes outside classical fat tissue depots and their necessity in tissue remodeling after injury. Therefore, we investigated the etiology of adipocytes in human granulation tissue and define their possible role wound healing.

Methods

Identification of human wound tissue adipocytes was determined by immunohistochemical staining of granulation tissue sections from patients undergoing surgical debridement. Stromal cell fractions from granulation tissue and subcutaneous fat tissue were generated by collagenase type II-based protocols. Pro- and anti-inflammatory wound bed conditions were mimicked by THP1- and CD14⁺ monocyte-derived macrophage models in vitro. Effects of macrophage secretome on ASC differentiation and metabolism were determined by immunoblotting, flow cytometry, and microscopy assessing early and late adipocyte differentiation states. Functional rescuing experiments were conducted by lentiviral transduction of wildtype PPARG, IL1RA, and N-chlorotaurine (NCT) treatment.

Results

Single and clustered adipocyte populations were detected in 11 out of 13 granulation tissue specimens and single-cell suspensions from granulation tissue showed adipogenic differentiation potential. Pro-inflammatory signaling by IFNG/LPS-stimulated macrophages (M (IFNG/LPS)) inhibited the maturation of lipid droplets in differentiated ASC. In contrast, anti-inflammatory IL4/IL13-activated macrophages (M (IL4/IL13)) revealed minor effects on adipocyte development. The M (IFNG/LPS)-induced phenotype was associated with a switch from endogenous fatty acid synthesis to glycolysis-dominated cell metabolism and increased pro-inflammatory cytokine production. Impaired adipogenesis was associated with increased, but seemingly non-functional, CEBPB levels, which failed to induce downstream PPARG and CEBPA. Neither transgenic PPARG overexpression, nor inhibition of IL1B was sufficient to rescue the anti-adipogenic effects induced by IFNG/LPS-activated macrophages. Instead, macrophage co-treatment during stimulation with NCT, a mild oxidant produced by activated granulocytes present in human wounds in vivo, significantly attenuated the anti-adipogenic effects.

Conclusions

In conclusion, the appearance of adipocytes in wound tissue indicates a prevailing anti-inflammatory environment that could be promoted by NCT treatment and may be associated with improved healing outcomes.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02336-3.

[Deep sternal wound infection after sternotomy - Report of the consensus workshop of the German-Speaking Society for Microsurgery of Peripheral Nerves and Vessels (DAM)]

Deep sternal wound infection (TSWI) is a potentially life-threatening complication that may occur after median sternotomy, contributing to prolonged hospital stay and increased health care costs. Bacterial infection is often characterized by biofilm formation on implant material and/or dead bone. Diagnosis is made upon clinical signs and symptoms of local and systemic infection. Early multidisciplinary decision making is needed for optimal patient care. Repeated surgical wound debridements accompanied by wound conditioning are performed until clean circumstances are achieved. Thereafter, wound closure and defect reconstruction are obtained using a variety of pedicled and microvascular flaps.

Sprouty1 Prevents Cellular Senescence Maintaining Proliferation and Differentiation Capacity of Human Adipose Stem/Progenitor Cells

The role of Ras-Mitogen-activated protein kinase (MAPK) signaling in cellular aging is not precisely understood. Recently, we identified Sprouty1 (SPRY1) as a weight-loss target gene in human adipose stem/progenitor cells (ASCs) and showed that Sprouty1 is important for proper regulation of adipogenesis. In the present study, we show that loss-of-function of Sprouty1 by CRISPR/Cas9-mediated genome editing in human ASCs leads to hyper-activation of MAPK signaling and a senescence phenotype. Sprouty1 knockout ASCs undergo an irreversible cell cycle arrest, become enlarged and stain positive for senescence-associated β-galactosidase. Sprouty1 down-regulation leads to DNA double strand breaks, a considerably increased number of senescence-associated heterochromatin foci and induction of p53 and p21^Cip1. In addition, we detect an increase of hypo-phosphorylated Retinoblastoma (Rb) protein in SPRY1 knockout ASCs. p16^Ink4A is not induced. Moreover, we show that Sprouty1 knockout leads to induction of a senescence-associated secretory phenotype as indicated by the activation of the transcription factors NFκB and C/EBPβ and a significant increase in mRNA expression and secretion of interleukin-8 (IL-8) and CXCL1/GROα. Finally, we demonstrate that adipogenesis is abrogated in senescent SPRY1 knockout ASCs. In conclusion, this study reveals a novel mechanism showing the importance of Sprouty1 for the prevention of senescence and the maintenance of the proliferation and differentiation capacity of human ASCs.

Quiescence, Stemness and Adipogenic Differentiation Capacity in Human DLK1-/CD34+/CD24+ Adipose Stem/Progenitor Cells

We explore the status of quiescence, stemness and adipogenic differentiation capacity in adipose stem/progenitor cells (ASCs) ex vivo, immediately after isolation from human subcutaneous white adipose tissue, by sorting the stromal vascular fraction into cell-surface DLK1⁺/CD34⁻, DLK1⁺/CD34^dim and DLK1⁻/CD34⁺ cells. We demonstrate that DLK1⁻/CD34⁺ cells, the only population exhibiting proliferative and adipogenic capacity, express ex vivo the bonafide quiescence markers p21^Cip1, p27^Kip1 and p57^Kip2 but neither proliferation markers nor the senescence marker p16^Ink4a. The pluripotency markers NANOG, SOX2 and OCT4 are barely detectable in ex vivo ASCs while the somatic stemness factors, c-MYC and KLF4 and the early adipogenic factor C/EBPβ are highly expressed. Further sorting of ASCs into DLK1⁻/CD34⁺/CD24⁻ and DLK1⁻/CD34⁺/CD24⁺ fractions shows that KLF4 and c-MYC are higher expressed in DLK1⁻/CD34⁺/CD24⁺ cells correlating with higher colony formation capacity and considerably lower adipogenic activity. Proliferation capacity is similar in both populations. Next, we show that ASCs routinely isolated by plastic-adherence are DLK1⁻/CD34⁺/CD24⁺. Intriguingly, CD24 knock-down in these cells reduces proliferation and adipogenesis. In conclusion, DLK1⁻/CD34⁺ ASCs in human sWAT exist in a quiescent state, express high levels of somatic stemness factors and the early adipogenic transcription factor C/EBPβ but senescence and pluripotency markers are barely detectable. Moreover, our data indicate that CD24 is necessary for adequate ASC proliferation and adipogenesis and that stemness is higher and adipogenic capacity lower in DLK1⁻/CD34⁺/CD24⁺ relative to DLK1⁻/CD34⁺/CD24⁻ subpopulations.

Long-term outcome after hand and forearm transplantation - a retrospective study

Between 2000 and 2014, five patients received bilateral hand (n = 3), bilateral forearm (n = 1), and unilateral hand (n = 1) transplants at the Innsbruck Medical University Hospital. We provide a comprehensive report of the long-term results at 20 years. During the 6-20 years follow-up, 43 rejection episodes were recorded in total. Of these, 27.9% were antibody-related with serum donor-specific alloantibodies (DSA) and skin-infiltrating B-cells. The cell phenotype in rejecting skin biopsies changed and C4d-staining increased with time post-transplantation. In the long-term, a change in hand appearance was observed. The functional outcome was highly depending on the level of amputation. The number and severity of rejections did not correlate with hand function, but negatively impacted on the patients´ well-being and quality of life. Patient satisfaction significantly correlated with upper limb function. One hand allograft eventually developed severe allograft vasculopathy and was amputated at 7 years. The patient later died due to progressive gastric cancer. The other four patients are currently rejection-free with moderate levels of immunosuppression. Hand transplantation remains a therapeutic option for carefully selected patients. A stable immunologic situation with optimized and individually adopted immunosuppression favors good compliance and patient satisfaction and may prevent development of DSA.

CRISPR/Cas9-mediated gene knockout in human adipose stem/progenitor cells

The CRISPR/Cas9 system is a powerful tool to generate a specific loss-of-function phenotype by gene knockout (KO). However, this approach is challenging in primary human cells. In this technical report, we present a reliable protocol to achieve a functional KO in the genome of human adipose stem/progenitor cells (ASCs). Using Sprouty1 (SPRY1) as a model target gene for a CRISPR/Cas9 mediated KO, we particularize the procedure including the selection of the CRISPR/Cas9 target sequences and the employment of appropriate lentiviral vectors to obtain a functional gene KO. The efficiency of CRISPR/Cas9 to mutate the SPRY1 gene is determined by a PCR-based mutation detection assay and sequence analysis. Effects on mRNA and protein levels are studied by RT-qPCR and Western blotting. In addition, we demonstrate that CRISPR/Cas9 mediated SPRY1 KO and gene silencing by shRNA are similarly effective to deplete the Sprouty1 protein and to inhibit adipogenic differentiation. In summary, we show a reliable approach to achieve a gene KO in human ASCs, which could also apply to other primary cell types. Abbreviations: ASC: Adipogenic Stem/Progenitor Cell; Cas: CRISPR-associated system; CRISPR: Clustered Regularly Interspaced Palindromic Repeat; gDNA: Genomic DNA; GOI: Gene of interest; gRNA: Guide RNA; NHEJ: Non-homologous end joining; Indel: Insertion/Deletion; PAM: Protospacer adjacent motif; sWAT: Subcutaneous white adipose tissue; TIDE: Tracking of indels by decomposition

Influence of Incision Site on Postoperative Outcome in Skin-/Nipple-Sparing Mastectomy: Is There a Difference between Radial and Inframammary Incision?

Background

The aim of this study was to determine whether there is a difference in results between the radial and the inframammary approach in nipple-/skin-sparing mastectomy and immediate reconstruction.

Methods

The patients were divided into two groups (group 1: radial incision; group 2: inframammary fold incision [IMF]), each consisting of two subgroups for direct-to-implant reconstruction (1a, 2a) and expander reconstruction (1b, 2b). The patients were operated on between March 2012 and May 2017. Preoperative tumor parameters, reconstruction parameters, postoperative tumor parameters, and immediate and late complications were assessed. Postoperative photographs were evaluated by the patients and 8 plastic surgeons by means of grading (1-5) and the visual analog scale (VAS; 1-10).

Results

Enrolled in this study were 28 patients, namely, 7 patients in each subgroup. The median age was 46 years, and the median follow-up period was 40 months. No immediate complications occurred. Three patients had late complications, but there was no case of evident capsular fibrosis. Twenty-seven patients (96.42%) evaluated the postoperative result as excellent/good. The postoperative evaluation by the plastic surgeons was excellent/good for a median of 18 patients (64.28%). Group 1 showed a median VAS score of 7.63 (expander group: 7.50; direct-to-implant group: 7.75); the median VAS score for group 2 was 8.25 (expander group: 8.75; direct-to-implant group: 7.50).

Conclusions

Our study shows good results for implant breast reconstruction in both groups, with minimally better results for the IMF group. In the direct-to-implant subgroups, the radial group showed slightly better results.

tBHP treatment as a model for cellular senescence and pollution-induced skin aging

Accumulation of senescent cells promotes the development of age-related pathologies and deterioration. In human skin, senescent cells potentially impair structure and function by secreting a mixture of signaling molecules and proteases that influence neighboring cells and degrade extracellular matrix components, such as elastin and collagen. One of the key underlying mechanisms of senescence and extrinsic skin aging is the increase of intracellular reactive oxygen species and resulting oxidative stress. Tert-butyl hydroperoxide (tBHP) is a known inducer of oxidative stress and cellular damage, acting at least in part by depleting the antioxidant glutathione. Here, we provide a detailed characterization of tBHP-induced senescence in human dermal fibroblasts in monolayer culture. In addition, results obtained with more physiological experimental models revealed that tBHP treated 3D reconstructed skin and ex vivo skin developed signs of chronic tissue damage, displaying reduced epidermal thickness and collagen fiber thinning. We, therefore, propose that tBHP treatment can be used as a model to study the effects of extrinsic skin aging, focusing mainly on the influence of environmental pollution.

[Establishing and evaluating a multinational Science Academy: A new tool for fostering scientific young talents in microsurgical research - a Consensus Statement of the DAM]

BACKGROUND

The formation of professional networks and cooperations - in addition to any qualified good education - seems fundamental for a successful career. In a number of disciplines, various symposia or conferences exist. In the field of microsurgery, however, a specific, guided and designated opportunity for junior scientists to network with one another has been missing so far.

METHODS

In 2017, a science academy was initiated for the first time by the German-speaking Association for Nerves and Vessels (DAM) with the goal of bringing together and networking microsurgically researching young physicians and scientists. This was intended to happen on a small scale once a year in order to develop synergies for joint research projects. For this purpose, motivated junior researchers were individually selected by their mentors and sent to the academy by the boards of research institutions that are organized in the DAM. After getting to know each other in a relaxed atmosphere, the participants were given the opportunity to present their respective research project within the framework of thematic blocks and moderated by experienced mentors. Each presentation was followed by a round table discussion and small group work, in which knowledge and methods were exchanged and points of contact for possible later cooperation were identified.

RESULTS

In the past 3 years, the DAM Science Academy proved to be an optimal format to initiate and promote networks of young researchers comprising microsurgically interested physicians and scientists. There were many lively and in-depth discussions, which were mainly due to the open working atmosphere and the obligation to confidentiality. Most of the synergies were shown i. a. in the field of angiogenesis, bioreactor, carcinoma-ADSC interactions, stem cells, AV loop model, ischemia/reperfusion, and nerve regeneration. The participants consistently gave a very positive feedback in the final evaluation with the wish to continue this academy.

CONCLUSION

The DAM Science Academy can be considered a highly suitable complemental platform to the existing networking opportunities among microsurgical researchers. Experience so far suggests that this will hopefully result in long-term cooperations and a permanent transfer of knowledge among the participants.

[Fistula prophylaxis with muscle-sparing, myofascial pectoralis major lobe in salvage laryngectomy]

BACKGROUND

In recurrent hypopharyngeal/laryngeal squamous cell carcinoma after radiation salvage-laryngectomy (salvage-LE) represents the best curative treatment option. Pre-irradiation promotes development of pharyngocutaneous fistulas (pc-fistula). Transfer of unirradiated tissue to the surgical site reduces fistula rate. Frequently, a myocutaneous Pectoralis-major-flap (PMF) is applied. We describe a muscle sparing, myofascial PMF (ms-PMF) and its functional & aesthetic results.

METHODS

For the ms-PMF, the pectoralis major is exposed via two 8 cm long subclavicular & submammary horizontal incisions. The pectoral branch of the thoracoacromial artery, which represents the blood supply for the ms-PMF, is identified between the clavicular and sternocostal aspect of the muscle. A craniocaudal stripe of the pectoralis major is recovered and supraclaviculary transposed towards the pharynx. The clavicular and sternocostal part of the muscle remain untouched.The clear-margin resection rate (CMRR), mean overall survival (OS), complications, median length of hospital stay, & functional & aesthetic outcome were assessed.

RESULTS

In 25 patients, salvage-LE with ms-PMF was performed. The CMRR was 100 %, median OS 1.3 (follow-up 2.8) years, complications rate 16 % (4 complete lobe necroses, 3 pc-fistulas) and median inpatient stay 20 (11-78) days. Good functional outcome were observed: limitations of oral food intake occurred in 2-, limitations in voice rehabilitation in 3 patients. Wound healing disorders without lobe necrosis were not observed. The aesthetic results were appealing.

CONCLUSION

The ms-PMF is a less invasive & safe procedure for fistula prophylaxis in salvage-LE with favorable functional & aesthetic results.

Breast reconstruction with the omentum flap: a case report with unsatisfactory outcome and review of the literature

Background

Recently, breast reconstruction with the greater omentum flap has gained more attention, although it has been only rarely reported in the literature. An unpleasant case presented by us here prompted us to perform a literature search on breast reconstruction with the omentum flap concerning postoperative results and complication rates.

Case presentation

We here present the case of a 46-year-old woman who presented with severe infection 3 months after omentum flap reconstruction in a distant local hospital. Intraoperative revision showed an inflammatory, completely necrotic flap that had to be removed.

Conclusion

The literature review shows that the omentum flap can be reasonably used only in one-sided reconstructions of very small breasts. Due to the limited indications, unpredictable flap volume, and our negative experience, we recommend that this type of reconstruction be used with restraint.

Skin grafting after paediatric palmar burns: an analysis of 82 patients

Contact burn injuries to the palm are common in toddlers. We report a case series of 82 paediatric patients (age 7-48 months) with contact burn injury of the palm. We share our experience and outcomes of using plantar split-thickness skin grafts for resurfacing of the paediatric palm. We found that despite the excellent colour and texture match, split-thickness skin grafts from glabrous skin during growth are prone to motion-limiting scare contracture. From this series, we conclude that full-thickness skin grafts remain the reference standard of care in paediatric patients' hands. We recommend that children with burn scars should have regular check-up examinations until they are fully grown. Level of evidence: IV.

The Pectoralis Major Island Flap: Short Scar Modified Muscle-Sparing Harvesting Technique Improves Aesthetic Outcome in Reconstructive Head and Neck Surgery

BACKGROUND

Pectoralis major flap reconstruction is often associated with large unappealing scars in head-neck surgery. We recently established an alternative harvesting technique that improves aesthetic outcome.

OBJECTIVES

The objective of this study was to demonstrate a modified surgical technique that harvests the pectoralis major muscle as an island flap and focuses on minimizing incision lines and applying a muscle-sparing approach.

METHODS

A retrospective analysis covering the period 2008-2018 was conducted. Patients who underwent pectoralis major island flap reconstruction for fistula prophylaxis after salvage laryngectomy at the Medical University of Innsbruck were included. Flap harvesting was performed subcutaneously using two small incision lines, thereby sparing the clavicular and upper sternocostal aspects of the pectoralis muscle.

RESULTS

Twenty-three patients with squamous cell carcinoma of the larynx (n = 19) or pharynx (n = 4) underwent salvage laryngectomy and consecutive reconstruction using a pectoralis major island flap and our muscle-sparing technique. Mean overall operation time was 147 ± 48.6 min. The majority (70%) of patients had an uneventful course of recovery and showed satisfying aesthetic results and low donor site morbidity as compared to traditional harvesting techniques. Six (26%) patients had major complications that required surgical revision. Three (13%) cases were complicated with fistulas.

CONCLUSION

The pectoralis major island flap is shown to be reliable in otolaryngeal surgery. This surgical technique minimizes scarring and preserves thoracic wall architecture by taking a less invasive approach, thereby improving aesthetic outcome and reducing overall patient morbidity.

Risk factors and complications after body-contouring surgery and the amount of stromal vascular fraction cells found in subcutaneous tissue

Body contouring surgery following massive weight loss is often prone to complications. Subcutaneous adipose tissue is a rich source of stromal vascular fraction (SVF) cells, and moreover it plays an important role in the pathophysiology of obesity, metabolic syndrome, and wound healing. In this retrospective, single-centred appraisal, complications are examined and correlated with individual SVF numbers in abdominal subcutaneous fat tissue. We analysed whether the weight loss method affected complications. Eighty seven massive weight loss patients undergoing body contouring surgery between 2010 and 2017 were included in the study. In total, 57 cases with at least one complication were recorded (65.5%). Maximum lifetime weight was 109.6 kg (range 48-184 kg). Half of the complications (50.8%) were minor complications without the need for surgical revision. The mean number of SVF found in the resected tissue was 714 997.63 cells/g fat tissue. We found no statistical difference in complication rates dependent on cell numbers. Smoking (P = .049) and a high BMI at the time point of surgery (P = .031) led to significantly more complications. Also, a high resection weight (P = .057) showed a tendency for impaired wound healing. However, there was no difference in complication rates following body contouring procedures attributable to the method of weight loss in this study.

[The interdisciplinary Microsurgeon - Results of the Consensus Workshop of the German Speaking Society for Microsurgery of Peripheral Nerves and Vessels]

Plastic and reconstructive surgery is characterized by a high degree of interdisciplinarity. Although Plastic surgery offers a wide range of reliable surgical treatment options independent departments for plastic and reconstructive surgery are not present in every university clinic or leading hospital in Germany. However, the ongoing improvements especially in the field of reconstructive microsurgery enabled and enhanced the treatment of complex defects in order to restore function as well as cosmetic outcome. Knowing the fact that patients are usually referred from other medical disciplines that are familiar with the development and treatment of the primary disease, creation of an interdisciplinary reconstructive treatment plan is crucial to guarantee best patient care. Thus, one of the future major challenges in plastic surgery will be the establishment of multidisciplinary boards in order to strengthen the role of plastic surgery within the medical system with the overall aim to solve complex reconstructive cases. During the 39^th annual meeting of the German Speaking Society for Microsurgery of Peripheral Nerves and Vessels a workshop titled "The interdisciplinary microsurgeon" addressed this topic. In the present article we will highlight the consented results of the workshop and provide pitfalls and pearls concerning the implementation process of different multidisciplinary boards based on representative examples.

Necrotizing fasciitis of the lower extremity caused by perforated sigmoid diverticulitis-a case report

Diverticulosis of the sigmoid colon is a common condition and occurs more often in elderly patients. A well-known complication is infection or even perforation which often requires surgery. Necrotizing fasciitis as a complication of perforated diverticulitis is very rare. Here, we present a case of a covered perforated diverticulitis in an immunosuppressed patient leading to life-threatening necrotizing fasciitis requiring extracorporeal membrane oxygenation. Either hematogenous or local dissemination via the inguinal canal seemed the most probable mechanism of leg infection leading to hip articulation.

Extracorporeal CO2 Removal in a Lung Lavage Induced Respiratory Distress Syndrome

Ten pigs with experimental respiratory distress syndrome were treated by extracorporeal CO2 removal (ECCO2-R) combined with low frequency positive pressure ventilation (LPPV). After lung damage had been induced by repeated lung lavages a PEEP trial was conducted in order to find the appropriate PEEP for the damaged lungs. This PEEP was then applied during the ECCO2-R/LPPV period. Blood gas values improved significantly on extracorporeal bypass within a short time (pre-bypass paO2: 54.2 ± 3.7 vs 168.5 ± 31.6 mmHg after 15 min on bypass, p < 0.001) and were kept constant during the next 4 hours. Minute ventilation (MV) was reduced from 4.01 ± 0.31 to 0.74 ± 0.07 l/min (p < 0.0001), FiO2 of the ventilator from 1.0 to 0.46 ± 0.08 (p < 0.0001) whereas FiO2 of the membrane lung (ML) was not changed significantly (FIO2ML 0.59 ± 0.07 vs 0.53 ± 0.06). During controlled mechanical ventilation (CMV), comparable adequate gas exchange was only achieved at a significantly higher mean airway pressure ([Formula: see text] vs 21.2 ± 0.47 cmH20, p < 0.0001). Hemodynamic variables did not change significantly during bypass time. ECCO2-R/LPPV driven by a simple renal perfusion system allows adequate gas exchange in experimental respiratory failure.

Presence of Biofilms on Polyurethane-Coated Breast Implants: Preliminary Results

Polyurethane-coated breast implants seem to be associated with lower medium- and long-term capsular contracture rates in comparison to textured or smooth implant surfaces. Although the etiology of capsular contracture is uncertain, bacterial biofilms have been suggested to trigger chronic peri-implant inflammation, eventually leading to capsular contracture. It is unknown whether polyurethane-coated implants are less prone to biofilm colonization than other implant surfaces. We extracted data from patient records included in a prospective cohort between 2008 and 2011. All patients who underwent removal of polyurethane-coated implants were included in this current study and screened for presence of biofilms by sonication. In addition, implant- and patient-related data were analyzed. Of the ten included polyurethane-coated breast implants, six had been inserted for reconstructive purposes and four for aesthetic reasons. The median implant indwelling time was 28.3 mo. Overall, sonication cultures were positive in 50% of implants. Propionibacterium acnes and coagulase-negative staphylococci were the predominant pathogens isolated from biofilm cultures. Like other implant surfaces, polyurethane-coated implants are prone to biofilm colonization. Further investigations are needed to determine why capsular contracture rates seem to be lower in polyurethane implants than in other implant surfaces. Notably, in this study, 40% of the implants were explanted from breasts with severe capsular contracture.

Immunophenotypic characterization of human T cells after in vitro exposure to different silicone breast implant surfaces

The most common complication of silicone breast implants is capsular contracture (massive scar formation around the implant). We postulate that capsular contracture is always a sequel to inflammatory processes, with both innate and adaptive immune mechanisms participating. In general, fibroblasts and macrophages have been used as cell types to evaluate in vitro the biocompatibility of breast implant surfaces. Moreover, also T cells have been found at the implant site at the initial stage of fibrous capsule formation. However, only few studies have addressed the influence of surfaces with different textures on T-cell responses. The aim of the present study was to investigate the immune response of human peripheral blood mononuclear cells (PBMC) to commercially available silicone breast implants in vitro. PBMC from healthy female blood donors were cultured on each silicone surface for 4 days. Proliferation and phenotype of cultured cells were assessed by flow cytometry. Cytokine levels were determined by multiplex and real-time assay. We found that silicone surfaces do not induce T-cell proliferation, nor do they extensively alter the proportion of T cell subsets (CD4, CD8, naïve, effector memory). Interestingly, cytokine profiling identified matrix specific differences, especially for IL-6 and TNF-α on certain surface topographies that could lead to increased fibrosis.

Spontaneous Regression of Two Giant Basal Cell Carcinomas in a Single Patient after Incomplete Excision

Background

Spontaneous regression of small basal cell carcinoma has been reported. For giant basal cell carcinoma, however, no spontaneous regression has been described to date.

Case report

We present a patient with two independent giant basal cell carcinomas over the left clavicle and the lower back, measuring 7 × 12 cm and 18 × 20 cm, respectively. Both tumors were excised incompletely (R2) and the patient refused follow-up resections. After 52 and 16 months, respectively, no signs of recurrence were observed.

Conclusion

Incompletely excised giant basal cell carcinomas can regress spontaneously. A watch-and-wait approach after incomplete resection may be pragmatic to avoid mutilating follow-up resections in patients refusing further surgery.

[Plastic reconstructive microsurgery in the elderly patient - Consensus statement of the German Speaking Working Group for Microsurgery of the Peripheral Nerves and Vessels]

During the last two decades, understanding and experience of microsurgical reconstruction have increased. This is linked to improved instruments and technical devices, as well as to the increased number of available donor sites for microvascular flap transfer. If the indication is appropriate, it is now possible to perform personalised, safe and successful microsurgical reconstructions, almost independently of the patients' age. Despite these constant developments, there is little specific literature on microsurgery related to the specific problems of the elderly patient. During two consensus workshops organised by the DAM (German Speaking Working Group for Microsurgery of the Peripheral Nerves and Vessels), the latest findings and experience with microsurgical reconstruction in the elderly patient were presented by a group of experts and current recommendations were formulated. On the basis of these consensus workshops and the current literature, this article discusses important issues in this area.

CD146 (MCAM) in human cs-DLK1-/cs-CD34+ adipose stromal/progenitor cells

To precisely characterize CD146 in adipose stromal/progenitor cells (ASCs) we sorted the stromal vascular faction (SVF) of human abdominal subcutaneous white adipose tissue (sWAT) according to cell surface (cs) expression of CD146, DLK1 and CD34. This test identified three main SVF cell populations: ~50% cs-DLK1^-/cs-CD34⁺/cs-CD146^- ASCs, ~7.5% cs-DLK1⁺/cs-CD34^dim/+/cs-CD146⁺ and ~7.5% cs-DLK1⁺/cs-CD34^dim/+/cs-CD146^- cells. All cells contained intracellular CD146. Whole mount fluorescent IHC staining of small vessels detected CD146⁺ endothelial cells (CD31⁺/CD34⁺/CD146⁺) and pericytes (CD31^-/CD34^-/CD146⁺ ASCs). The cells in the outer adventitial layer showed the typical ASC morphology, were strongly CD34⁺ and contained low amounts of intracellular CD146 protein (CD31^-/CD34⁺/CD146⁺). Additionally, we detected wavy CD34^-/CD146⁺ and CD34^dim/CD146⁺ cells. CD34^dim/CD146⁺ cells were slightly more bulky than CD34^-/CD146⁺ cells. Both CD34^-/CD146⁺ and CD34^dim/CD146⁺ cells were detached from the inner pericyte layer and protruded into the outer adventitial layer. Cultured early passage ASCs contained low levels of CD146 mRNA, which was expressed in two different splicing variants, at a relatively high amount of the CD146-long form and at a relatively low amount of the CD146-short form. ASCs contained low levels of CD146 protein, which consisted predominantly long form and a small amount of short form. The CD146 protein was highly stable, and the majority of the protein was localized in the Golgi apparatus. In conclusion, the present study contributes to a better understanding of the spatial localization of CD34⁺/CD146⁺ and CD34^-/CD146⁺ cells in the adipose niche of sWAT and identifies CD146 as intracellular protein in cs-DLK1^-/cs-CD34⁺/cs-CD146^- ASCs.

A small 'lick' will sink a great ship: fulminant septicaemia after dog saliva wound treatment in an asplenic patient

Capnocytophaga canimorsus is a bacterium transmitted through the saliva of dogs. An infection can cause severe sepsis with acral necrosis and is potentially fatal. Here, we report the case of a 41-year-old man who was infected through a wound that was licked by his dog. He went into septic shock with disseminated intravascular coagulation and subsequently lost both lower legs, his nose and all the fingers on both hands.

Comparison of fasciocutaneous V-Y and rotational flaps for defect coverage of sacral pressure sores: a critical single-centre appraisal

Pressure sore rates remain high in both nursing homes as well as in hospitals. Numerous surgical options are available for defect coverage in the sacral region. However, objective data is scarce as to whether a specific flap design is superior to another. Here, we aim to compare two fasciocutaneous flap designs for sacral defect coverage: the gluteal rotation flap and the gluteal V-Y flap. All primary sacral pressure sores of grades III-IV that were being covered with gluteal fasciocutaneous rotational or V-Y flaps between January 2008 and December 2014 at our institution were analysed. A total of 41 patients received a total of 52 flaps. Of these, 18 patients received 20 gluteal rotational flaps, and 23 patients received 32 V-Y flaps. Both groups were comparable with regards to demographics, comorbidities and complications. Significantly more V-Y flaps were needed to cover smaller defects. Mean length of hospital stay was significantly prolonged when surgical revision had to be carried out. Both flap designs have proven safe and reliable for defect coverage after sacral pressure sores. Gluteal rotational flaps appear to be more useful for larger defects. Both flap designs facilitate their reuse in case of pressure sore recurrence. Complication rates appear to be comparable in both designs and to the current literature.

Functional and Psychosocial Outcomes of Hand Transplantation Compared with Prosthetic Fitting in Below-Elbow Amputees: A Multicenter Cohort Study

Background

Hand-transplantation and improvements in the field of prostheses opened new frontiers in restoring hand function in below-elbow amputees. Both concepts aim at restoring reliable hand function, however, the indications, advantages and limitations for each treatment must be carefully considered depending on level and extent of amputation. Here we report our findings of a multi-center cohort study comparing hand function and quality-of-life of people with transplanted versus prosthetic hands.

Methods

Hand function in amputees with either transplant or prostheses was tested with Action Research Arm Test (ARAT), Southampton Hand Assessment Procedure (SHAP) and the Disabilities of the Arm, Shoulder and Hand measure (DASH). Quality-of-life was compared with the Short-Form 36 (SF-36).

Results

Transplanted patients (n = 5) achieved a mean ARAT score of 40.86 ± 8.07 and an average SHAP score of 75.00 ± 11.06. Prosthetic patients (n = 7) achieved a mean ARAT score of 39.00 ± 3.61 and an average SHAP score of 75.43 ± 10.81. There was no significant difference between transplanted and prosthetic hands in ARAT, SHAP or DASH. While quality-of-life metrics were equivocal for four scales of the SF-36, transplanted patients reported significantly higher scores in “role-physical” (p = 0.006), “vitality” (p = 0.008), “role-emotional” (p = 0.035) and “mental-health” (p = 0.003).

Conclusions

The indications for hand transplantation or prosthetic fitting in below-elbow amputees require careful consideration. As functional outcomes were not significantly different between groups, patient’s best interests and the route of least harm should guide treatment. Due to the immunosuppressive side-effects, the indication for allotransplantation must still be restrictive, the best being bilateral amputees.

[Perioperative Management in Microsurgery - Consensus Statement of the German Speaking Society for Microsurgery of Peripheral Nerves and Vessels]

Perioperative management of microsurgery is not well standardised. Due to a lack of evidence, different regimes are established in different microsurgical centres. However, trends towards less aggressive perioperative interventions can be identified in recent years, since treatment algorithms without systematic evidence are being progressively abandoned. The available evidence on perioperative issues, such as temperature control, fluid resuscitation, blood transfusions, application of vasodilators or - pressors, as well as anticoagulants, were discussed during the consensus conference on perioperative management at the annual meeting of the German Speaking Society for Microsurgery of Peripheral Nerves and Vessels. Common basic standards were identified and a consensus was reached that is described in the following manuscript.

The versatility of the medial thigh lift for defect coverage in the genito-perineal region

Soft tissue defects in the genito-perineal region are predominantly because of trauma, infections, neoplasms or iatrogenic causes. As a result of the region's urological, reproductive and gastrointestinal function, defects in this area may cause devastating physical and psychological consequences as well as diminished sexual functioning. The purpose of this study was to examine the efficacy of implementing a medial thigh lift for defect coverage in the perineal region. A retrospective analysis of all medial thigh lift procedures for defect coverage in the genito-perineal region between November 2010 and March 2015 was conducted at three institutions. Ten consecutive patients underwent a medial thigh lift for defect coverage in the genito-perineal region. Nine patients were male, and one was female. The causative factors were Fournier's gangrene in eight patients, one patient had a straddle injury, and one suffered from extramammary Paget's disease. The mean follow-up time was 19·8 months. The average total defect size was 11·1 × 11 cm (length × width). The medial thigh lift procedure is a safe, technically easy and reliable technique with discrete scars. Outstanding aesthetic and functional outcomes result in a high rate of patient satisfaction. Through immediate wound closure, a reduction of recovery time can be achieved.

ITGAV and ITGA5 diversely regulate proliferation and adipogenic differentiation of human adipose derived stem cells

The fate of human adipose tissue stem cells (ASCs) is largely determined by biochemical and mechanical cues from the extracellular matrix (ECM), which are sensed and transmitted by integrins. It is well known that specific ECM constituents influence ASC proliferation and differentiation. Nevertheless, knowledge on how individual integrins regulate distinct processes is still limited. We performed gene profiling of 18 alpha integrins in sorted ASCs and adipocytes, identifying downregulations of RGD-motif binding integrins integrin-alpha-V (ITGAV) and integrin-alpha-5 (ITGA5), upregulation of laminin binding and leukocyte-specific integrins and individual regulations of collagen and LDV-receptors in differentiated adipocytes in-vivo. Gene function analyses in in-vitro cultured ASCs unraveled differential functions of ITGA5 and ITGAV. Knockdown of ITGAV, but not ITGA5 reduced proliferation, caused p21^Cip1 induction, repression of survivin and specific regulation of Hippo pathway mediator TAZ. Gene knockdown of both integrins promoted adipogenic differentiation, while transgenic expression impaired adipogenesis. Inhibition of ITGAV using cilengitide resulted in a similar phenotype, mimicking loss of pan-ITGAV expression using RNAi. Herein we show ASC specific integrin expression patterns and demonstrate distinct regulating roles of both integrins in human ASCs and adipocyte physiology suggesting a negative impact of RDG-motif signaling on adipogenic differentiation of ASCs via ITGA5 and ITGAV.

Weight Loss Upregulates the Small GTPase DIRAS3 in Human White Adipose Progenitor Cells, Which Negatively Regulates Adipogenesis and Activates Autophagy via Akt-mTOR Inhibition

Long-term weight-loss (WL) interventions reduce insulin serum levels, protect from obesity, and postpone age-associated diseases. The impact of long-term WL on adipose-derived stromal/progenitor cells (ASCs) is unknown. We identified DIRAS3 and IGF-1 as long-term WL target genes up-regulated in ASCs in subcutaneous white adipose tissue of formerly obese donors (WLDs). We show that DIRAS3 negatively regulates Akt, mTOR and ERK1/2 signaling in ASCs undergoing adipogenesis and acts as a negative regulator of this pathway and an activator of autophagy. Studying the IGF-1–DIRAS3 interaction in ASCs of WLDs, we demonstrate that IGF-1, although strongly up-regulated in these cells, hardly activates Akt, while ERK1/2 and S6K1 phosphorylation is activated by IGF-1. Overexpression of DIRAS3 in WLD ASCs completely inhibits Akt phosphorylation also in the presence of IGF-1. Phosphorylation of ERK1/2 and S6K1 is lesser reduced under these conditions. In conclusion, our key findings are that DIRAS3 down-regulates Akt–mTOR signaling in ASCs of WLDs. Moreover, DIRAS3 inhibits adipogenesis and activates autophagy in these cells.

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Long-term weight loss (WL) induces DIRAS3 and IGF-1 in ASCs of sWAT in formerly obese humans.

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DIRAS3 selectively down-regulates IGF-1R-Akt–mTOR signaling in ASCs and channels the IGF-1 stimulus to the ERK1/2 branch.

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DIRAS3 inhibits adipogenesis and activates autophagy in ASCs.

Long-term weight loss (WL) interventions reduce insulin serum levels, protect from obesity and postpone age-associated diseases. The impact of WL on adipose-derived stromal/progenitor cells (ASCs), stem cell-like cells in human subcutaneous white adipose tissue (sWAT), is not understood. We found that WL induced GTP-binding RAS-like 3 (DIRAS3) and insulin-like growth factor 1 (IGF-1), regulators of the IGF-1–mTOR signal transduction pathway, in ASCs in sWAT of formerly obese humans. We demonstrate that DIRAS3 selectively down-regulates IGF-1R–Akt–mTOR signaling in ASCs upon WL even in the presence of high IGF-1 level and that DIRAS3 inhibits adipogenesis and activates autophagy in these cells.

Characterization of DLK1(PREF1)+/CD34+ cells in vascular stroma of human white adipose tissue

Sorting of native (unpermeabilized) SVF-cells from human subcutaneous (s)WAT for cell surface staining (cs) of DLK1 and CD34 identified three main populations: ~10% stained cs-DLK1+/cs-CD34-, ~20% cs-DLK1+/cs-CD34+dim and ~45% cs-DLK1-/cs-CD34+. FACS analysis after permeabilization showed that all these cells stained positive for intracellular DLK1, while CD34 was undetectable in cs-DLK1+/cs-CD34- cells. Permeabilized cs-DLK1-/cs-CD34+ cells were positive for the pericyte marker α-SMA and the mesenchymal markers CD90 and CD105, albeit CD105 staining was dim (cs-DLK1-/cs-CD34+/CD90+/CD105+dim/α-SMA+/CD45-/CD31-). Only these cells showed proliferative and adipogenic capacity. Cs-DLK1+/cs-CD34- and cs-DLK1+/cs-CD34+dim cells were also α-SMA+ but expressed CD31, had a mixed hematopoietic and mesenchymal phenotype, and could neither proliferate nor differentiate into adipocytes. Histological analysis of sWAT detected DLK1+/CD34+ and DLK1+/CD90+ cells mainly in the outer ring of vessel-associated stroma and at capillaries. DLK1+/α-SMA+ cells were localized in the CD34- perivascular ring and in adventitial vascular stroma. All these DLK1+ cells possess a spindle-shaped morphology with extremely long processes. DLK1+/CD34+ cells were also detected in vessel endothelium. Additionally, we show that sWAT contains significantly more DLK1+ cells than visceral (v)WAT. We conclude that sWAT has more DKL1+ cells than vWAT and contains different DLK1/CD34 populations, and only cs-DLK1-/cs-CD34+/CD90+/CD105+dim/α-SMA+/CD45-/CD31- cells in the adventitial vascular stroma exhibit proliferative and adipogenic capacity.

Outcomes for split-thickness skin transplantation in high-risk patients using octenidine

Skin transplantation is a commonly used surgical technique; however, the complication rate, including postoperative infection and delayed wound healing due to inefficient perfusion, is significantly higher in patients suffering from comorbidities. Hence, a subsequent repeat procedure is often necessary. In this report, two case studies are presented in which an octenidine-based antiseptic is used with a tie-over dressing (TOD) instead of povidone iodine (PVP-iodine), following a split-thickness skin graft. The two patients selected were deemed to be at high risk of impaired wound healing due to comorbidities. The first patient, a confirmed smoker with diabetes, presented with a nodular melanoma that was resected and covered with a split-thickness skin graft. After 5 days of negative pressure wound therapy as a TOD, in combination with PVP-iodine, the graft became necrotic. A second split-thickness skin graft was performed and an antiseptic regimen with octenidine in combination with the same TOD resulted in a completely healed transplant. The second patient, also a confirmed smoker with diabetes and receiving oral corticosteroid treatment, was diagnosed with a skin necrosis on her leg. Following the split-thickness skin graft, octenidine and TOD were applied. The patient's skin graft completely healed without any adverse events. These two case studies indicate that the combination of octenidine and TOD following split-thickness skin transplantation is safe, well-tolerated and appears to have positive benefits in the reconstruction of defects in patients with impaired wound healing.

The combined use of NPWT and instillation using an octenidine based wound rinsing solution: a case study

Effective wound bed preparation is an essential element in the healing of chronic wounds, including pressure ulcers (PUs). Negative pressure wound therapy (NPWT) reduces oedema, stimulates the formation of granulation tissue and helps remove wound exudate. This helps prepare the wound bed for secondary healing, skin grafting or coverage with flaps. Combining NPWT with an instillation phase using an antiseptic (octenidine based) irrigation solution is a novel approach to PU management. Three patients with Category 4 gluteal PUs were treated with NPWT and instillation fluid, following surgical debridement of necrotic tissue. The aim was to achieve optimal wound bed preparation prior to wound closure by local fasciocutaneous flap. The antiseptic efficacy of octenilin wound irrigation solution in microorganism eradication was quantified by in vitro tests simulating real conditions using leg ulcer vacuum exudates. All wounds completely healed after four weeks, and no adverse incidents occurred due to instillation of octenidine. No recurrence of the PU occurred during a one year follow-up.

Long-term quality-of-life improvement in gastric banding patients from body-contouring surgery

Following my prior study of long-term results after laparoscopic gastric banding concerning operative outcome and complications involving the gastric band itself, I now focus on long-term quality-of-life improvement in the same study group after body-contouring surgery. As determined from our electronic patient data system, 72 patients from the former study group subsequently sought body-contouring surgery at our hospital after successful weight loss. Patients were enrolled in a telephone interview and asked about their expectations and body image before and after postbariatric aesthetic surgery and how it altered their well-being in addition to the weight loss achieved with the gastric band. All patients undergoing postbariatric aesthetic surgery felt extremely uneasy with the hanging skin resulting from weight reduction. Patients cannot imagine the degree of dissatisfaction they will experience from the sagging skin that comes with weight loss. Hardly any patient expected fewer scars than he ultimately had after body-contouring surgery and reported an extreme improvement in body image. Gastric banding should not be performed without informing patients about the need for postbariatric body-contouring surgery, because most patients not forewarned suffer greatly from their body image after weight loss.

Long-term Quality-of-life Improvement in Gastric Banding Patients from Body-contouring Surgery

Following my prior study of long-term results after laparoscopic gastric banding concerning operative outcome and complications involving the gastric band itself, I now focus on long-term quality-of-life improvement in the same study group after body-contouring surgery. As determined from our electronic patient data system, 72 patients from the former study group subsequently sought body-contouring surgery at our hospital after successful weight loss. Patients were enrolled in a telephone interview and asked about their expectations and body image before and after postbariatric aesthetic surgery and how it altered their well-being in addition to the weight loss achieved with the gastric band. All patients undergoing postbariatric aesthetic surgery felt extremely uneasy with the hanging skin resulting from weight reduction. Patients cannot imagine the degree of dissatisfaction they will experience from the sagging skin that comes with weight loss. Hardly any patient expected fewer scars than he ultimately had after body-contouring surgery and reported an extreme improvement in body image. Gastric banding should not be performed without informing patients about the need for postbariatric body-contouring surgery, because most patients not forewarned suffer greatly from their body image after weight loss.