Dynamic cultivation of human mesenchymal stem/stromal cells for the production of extracellular vesicles in a 3D bioreactor system.

PURPOSE: 3D cell culture and hypoxia have been demonstrated to increase the therapeutic effects of mesenchymal stem/stromal cells (MSCs)-derived extracellular vesicles (EVs). In this study, a process for the production of MSC-EVs in a novel 3D bioreactor system under normoxic and hypoxic conditions was established and the resulting EVs were characterized. METHODS: Human adipose-derived MSCs were seeded and cultured on a 3D membrane in the VITVO® bioreactor system for 7 days. Afterwards, MSC-EVs were isolated and characterized via fluorescence nanoparticle tracking analysis, flow cytometry with staining against annexin V (Anx5) as a marker for EVs exposing phosphatidylserine, as well as CD73 and CD90 as MSC surface markers. RESULTS: Cultivation of MSC in the VITVO® bioreactor system demonstrated a higher concentration of MSC-EVs from the 3D bioreactor (9.1 × 109 ± 1.5 × 109 and 9.7 × 109 ± 3.1 × 109 particles/mL) compared to static 2D culture (4.2 × 109 ± 7.5 × 108 and 3.9 × 109 ± 3.0 × 108 particles/mL) under normoxic and hypoxic conditions, respectively. Also, the particle-to-protein ratio as a measure for the purity of EVs increased from 3.3 × 107 ± 1.1 × 107 particles/µg protein in 2D to 1.6 × 108 ± 8.3 × 106 particles/µg protein in 3D. Total MSC-EVs as well as CD73-CD90+ MSC-EVs were elevated in 2D normoxic conditions. The EV concentration and size did not differ significantly between normoxic and hypoxic conditions. CONCLUSION: The production of MSC-EVs in a 3D bioreactor system under hypoxic conditions resulted in increased EV concentration and purity. This system could be especially useful in screening culture conditions for the production of 3D-derived MSC-EVs.

[Comparison of Two Umbilicoplasty Techniques in 72 Patients after Breast Reconstruction with a Free DIEP Flap] / Vergleich zweier Techniken der Umbilikoplastik bei 72 Patientinnen nach Brustrekonstruktion mit freier DIEP-Lappenplastik.

INTRODUCTION: The appearance of the umbilicus after DIEP flap surgery or abdominoplasty plays an important role in aesthetic perception (1). Although the umbilicus has no function, there is no doubt about the importance of its shape for the self-esteem of patients, especially after breast cancer (2). In the present study, we compared two of the preferred techniques described in the literature on 72 patients in terms of aesthetic outcome, complications and sensitivity: the caudal flap (domed shape) and the oval shape of the umbilicus. PATIENTS AND METHODS: Seventy-two patients who underwent a DIEP flap for breast reconstruction between January 2016 and July 2018 were retrospectively included in this study. Two techniques for umbilical reconstruction were compared: the transverse oval shape of the umbilicus and umbilicoplasty using a caudal flap, which results in a dome shape of the umbilicus. To compare the aesthetic results, an evaluation by the patients and an assessment by three independent plastic surgeons were carried out at least 6 months postoperatively. Patients and surgeons were asked to rate the general appearance of the umbilicus, including scarring and shape, on a scale from 1 to 6 (1=very good, 2=good, 3=fair, 4=sufficient, 5=poor, 6=insufficient). Furthermore, the occurrence of wound healing disorders was examined, and patients were asked about the sensitivity of the umbilicus. RESULTS: Both techniques showed similar degrees of aesthetic satisfaction (p=0,49) as part of the patients' self-assessment. The plastic surgeons gave the caudal flap technique a significantly better rating than the umbilicus with a transverse oval shape (p=0,042). More wound healing disorders occurred in the caudal lobule (11,1%) compared with the transverse oval umbilicus. However, this was not significant (p=0,16). A surgical revision was not necessary. The caudal flap umbilicus showed a tendency to improved sensitivity (60 vs. 45%), but this was not significant (p=0,19). CONCLUSION: Patient satisfaction showed similar results for the two methods of umbilicoplasty. On average, both techniques were given a good rating for their results. However, surgeons rated the caudal flap umbilicoplasty as more aesthetically pleasing.

Decreasing Time Intervals in Recurring Capsular Contracture? A Single Center Retrospective Study over 6 Years.

Although breast implants of the current generation can, in principle, remain in the body for life, follow-up operations of the augmented or reconstructed breasts are regularly necessary. Capsular contracture is the leading cause for revisional surgery. The aim of this study was to evaluate indications and changes in time intervals between consecutive implant replacements with a focus on capsular contracture. Methods: In the period from 2012 to 2017, all patients with breast implant replacements or removals at our institution were identified. From the medical file, the time of the first implantation and earlier replacements were analyzed for indication and timing of surgery. Results: A total of 498 operations for implant replacement or removal were analyzed in 323 patients. Including prior operations, 717 procedures could be evaluated. If capsular contracture was the indication, revision surgery was performed on average 14.3 years or 8.4 years in aesthetic or reconstructive cases, respectively. In patients with more than one implant removal or replacement, we saw a reduction in the time interval between the first, second, and third follow-up operation. Conclusions: The main indication to perform implant replacements or removals was capsular contracture recurring at increasingly shorter intervals. Patients must be informed about this possible progression when changing implants, but also before the first operation. If capsular contracture occurs after a rather short time period in reconstructive cases, the opportunity of an alternative approach (eg, autologous reconstruction) instead of a renewed implant change should be discussed with the patient.

Retroauricular lymph node flap: An anatomic and surgical feasibility study.

BACKGROUND: The study investigated the anatomy of the retroauricular lymph node (LN) flap and evaluate its surgical feasibility as a new donor site for a free LN flap in lymphedema surgery. METHODS: Twelve adult cadavers were examined. The course and perfusion of the anterior auricular artery (AAA) and the location and sizes of the retroauricular LNs were studied. RESULTS: The AAA was available in 87% and absent in 13% specimens. The AAA's origin had a mean vertical distance of 12.2 ± 6.9 mm and a mean horizontal distance of 19.1 ± 4.2 mm from the superior attachment of the ear. The mean diameter of the AAA was 0.8 ± 0.2 mm. The mean number of LN per region was 7.7 ± 2.3, with an average LN size of 4.1 ± 1.9 × 3.2 ± 1.7 mm. The LN were categorized into anterior (G1) and posterior (G2) groups, with a total of 59 and 10 LN, respectively. In a cluster analysis, three LN clusters could be detected across the anterior group (G1). CONCLUSIONS: The retroauricular LN flap is a delicate but feasible flap with reliable anatomy, containing a mean of 7.7 LNs.

Sichere Diagnostik der Implantatrotation im hochauflösenden Ultraschall in Abhängigkeit vom Implantathersteller.

Rotation of an anatomical breast implant may require revisional surgery. High-resolution ultrasound can help determine the exact implant alignment. However, the directional markings of anatomical implants are implemented very inconsistently by manufacturers. Therefore, a definite diagnosis is often not possible without precise knowledge of the expected imaging. The aim of this work is a differentiation of the imaging of common implant brands in high-resolution ultrasound. Methods To simulate an authentic imaging, anatomical implants were viewed through abdominal skin thinned to 1.5-2 cm, which was obtained during a classic abdominoplasty. Implants from the companies Allergan, Eurosilicone, Mentor, Motiva, Nagor, Polytech and Sebbin were compared. The marking positions and dimensions were documented by ultrasound. Results Based on placement and shape, a clear allocation between alignment and manufacturer is basically possible among the implants used. The base plate and caudal markers could be clearly visualised for all brands. In Polytech implants, however, the visible structural change is limited to a very small central area. The visualisation of directional marks, base plate and implant shell also allow conclusions to be drawn about the manufacturer. In high-resolution ultrasound, a fast and reliable diagnosis of implant alignment is possible for all implants examined. Also it was possible to make a clear allocation between implant and manufacturer in this context. Flip over of the implant can also be reliably depicted. The cataloguing of the markings summarised here can be used to determine the exact alignment of the implant and thus provide diagnostic certainty, especially if the brand is unknown.

Topische Applikation von Tranexamsäure im Rahmen der subkutanen Mastektomie bei Frau-zu-Mann Transidentität.

INTRODUCTION: Tranexamic acid (TXA) is an antifibrinolytic drug that can be used to treat and prevent bleeding. Its application in plastic and reconstructive surgery has been very limited to date. To our knowledge, there is a lack of published data on the topical application of TXA in transgender patients undergoing subcutaneous mastectomy. METHODS: We performed a retrospective data analysis of female-to-male transgender patients who underwent subcutaneous mastectomy. A total of 22 patients were treated with topical TXA, while 29 patients served as controls. The primary endpoint was the amount of wound secretion in the first 48 hours after surgery. Secondary endpoints were the duration of drainage and the occurrence of postoperative bleeding. RESULTS: Within the first 48 hours, the TXA group had an average drain volume of 97±50 ml compared with 180±111 ml in the control group (p<0.01). There was a significantly lower flow rate over the entire period in the group of TXA patients (113±86 ml vs. 265±197 ml). The time of drains in situ was 2.3±0.7 days in TXA patients, while the drains in the control group were in place for an average of 3.4±1.3 days (p<0.01). In the group of patients treated with TXA, there was a tendency towards a lower number of postoperative bleeding and haematoma (9vs. 17%). DISCUSSION: There was a significant reduction in the amount of drain fluid within the first 48 hours and over the entire period after topical application of TXA. Also there was a reduction in the length of time patients had a drain in place in the TXA-treated patients. This study demonstrated a significant advantage for the topical application of TXA in subcutaneous mastectomy in female-to-male transgender patients.

[Treatment of phyllodes tumours of the breast: evaluation of 66 cases and literature review]. / Zur Therapie von Phylloides-Tumoren der Brust ­ eine Aufarbeitung von 66†Fällen mit Literaturübersicht.

Phyllodes tumours (PTs) of the breast are classified as benign, borderline and malignant based on the constellation of defined histological parameters. Surgical excision is the primary therapy, but the need to maintain certain safety margins is still controversially discussed for all three categories.This paper aims to provide a critical opinion on the existing recommendation on safety margins for resection.In our breast centre, all patients with phyllodes tumours were identified retrospectively on the basis of the histopathological documentation from 1999 to 2018. The cases were evaluated, in particular, with a view to recurrences and the occurrence of multicentricity.A total of 66 patients were diagnosed with a PT. In 38 cases, the tumours were benign, in 15 borderline and in 13 malignant. Local recurrences were observed in one benign PT, 7 borderline and 5 malignant PTs. Two PTs that were initially classified as borderline tumours progressed to malignant PTs. Multicentricity occurred in about 20 % of borderline and malignant PTs but only in 5 % of benign PTs.The resection margins for phyllodes tumours should be chosen depending on dignity and recurrence. The key question to be challenged is whether or not there is a need to maintain a certain safety margin in benign PTs. In case of recurrence of borderline or malignant PTs, a mastectomy should be considered early.

[How well are patients informed on the websites of German university breast centres about the possibilities of breast reconstruction?] / Wie gut werden Patientinnen auf Internetseiten von deutschen universitären Brustzentren über die Möglichkeiten der Brustrekonstruktion informiert?

INTRODUCTION: In recent decades, the internet has become one of the most important sources of information for patients. How substantial are the possibilities to find out about breast reconstruction on the homepages of university hospitals in Germany? Is there information about plastic surgery with its spectrum of modern reconstructive possibilities? METHODS: A total of 35 homepages of university breast centres in Germany was analysed for the indication of cooperation with a plastic surgeon or a department for plastic surgery and their links, with information on reconstructive possibilities such as implant reconstruction, autologous soft tissue reconstruction with pedicled and free flaps as well as lipofilling. RESULTS: A plastic surgeon or a cooperating department is mentioned on 49 % of the homepages. Of those homepages, 20 % contain a direct link. 91 % of the homepages describe the possibility of breast reconstruction in general, 80 % of the websites the use of autologous tissue. In 51 % of the cases, a free tissue transfer is mentioned, whereas only 23 % describe the procedures like DIEP flap, TMG, or I-GAP in more detail. Only two centres use detailed illustrations. Six websites (17 %) describe reconstruction by pedicled TRAM flap only. Breast reconstruction with a silicone implant is mentioned on 71 % of the websites. The possibility of lipofilling is discussed in 31 %. DISCUSSION: About half of the websites of university breast centres do not show any cooperation with a plastic surgeon. There are significant gaps in the information on free tissue transfer for breast reconstruction.

Botulinum Toxin A: Dose-dependent Effect on Reepithelialization and Angiogenesis.

BACKGROUND: Botulinum (neuro)toxin A (BoNT) is widely used in the field of plastic and reconstructive surgery. Among treatment of pain, hyperhidrosis, or aesthetic purposes, it is also used to enhance wound healing and prevent excessive scar formation. Some clinical data already exist, but only little is known on a cellular level. The aim of this study was to evaluate the effect of BoNT on cells essential for wound healing in vitro. Therefore, primary human keratinocytes and endothelial cells were treated with different concentrations of BoNT and tested on proliferation, migration, and angiogenic behavior. METHODS: BoNT was exposed to human keratinocytes and endothelial cells in a low (1 IU/mL), medium (10 IU/mL), and high (20 IU/mL) concentrations in cell culture. Proliferation and migration of the 2 cell types were observed and also the angiogenic potential of endothelial cells in vitro. RESULTS: BoNT 20 IU/mL negatively influenced proliferation and migration of keratinocytes but not those of endothelial cells. Angiogenesis in vitro was less effective with the highest BoNT concentrations tested. Low concentrations of BoNT supported sprouting of endothelial cells. CONCLUSIONS: High concentrations of botulinum toxin interfered with wound closure as keratinocytes' proliferation and migration were deteriorated. Furthermore, BoNT concentrations of 20 IU/mL constrain in vitro vessel formation but do not influence proliferation or migration of endothelial cells.

Plastic reconstructive surgery techniques using VRAM or gracilis flaps in order to successfully treat complex urogenital fistulas.

BACKGROUND: Urogenital fistulas are devastating complications occurring after tumors or trauma. Surgical treatment is challenging. Thus, further surgical repair options are needed for treatment of complex fistulas within the pelvic region. METHODS: Twelve patients with urogenital fistulas were surgically treated in our department from 2004 to 2012. These selected cases fulfilled eligibility criteria for continence-preserving surgery - a history of fistula recurrences with ongoing incontinence after receiving at least two surgical attempts. Five VRAM and eight gracilis flaps were used to cover up given tissue defects and to perform functional continence-preserving reconstruction with mean follow-up of 6.3 years. Data were retrospectively reviewed, and standardized survey was performed to evaluate quality of life of all living patients (n = 10). RESULTS: In all cases, final surgical treatment of the given fistulae by VRAM or gracilis flaps could be achieved, with mean operating time of 5:31 h (range: 4:50-6:48 h) for VRAM flap and 3:11 h (range: 2:04-4:42 h) for gracilis flap. Outcome measures were primarily to avoid fistula recurrence after plastic surgical treatment, and secondary quality of life and survival. All patients had their continence preserved, but two patients died during follow-up period. Postoperative assessment revealed the following: VRAM flap patients (n = 3) showed slight incontinence during the follow-up period, whereas continence was restored in all patients with gracilis flap reconstruction (n = 7). Quality-of-life assessment indicated restoration of quality of life in comparison to general population (women > men). Furthermore, key points of the two presented surgical techniques are demonstrated in detail. CONCLUSION: With preformed VRAM or gracilis flaps, complex urogenital fistulas can be successfully eradicated and continence is restored. The main focus should be the recovery of quality of life, which could be successfully regained. Nevertheless, the continence success rate has to be defined on an individual, case-by-case basis. LEVEL OF EVIDENCE: Original work, cohort study level III.

Wound Healing Effect of Conditioned Media Obtained From Adipose Tissue on Human Skin Cells: A Comparative in Vitro Study.

BACKGROUND: Split-thickness skin grafting is the gold standard to cover extensive acute and chronic wounds with a well-vascularized wound bed. Although some headway has been made in developing biological agents to speed up healing, there is still no treatment that sufficiently replaces skin grafts to date. The use of secretory factors of adipose tissue may be a feasible approach to developing topical wound applications for faster wound healing. METHODS: In this study, the effect of conditioned media (CMs) of human adipose-derived stem cells (ASCs), adipocytes, or adipose tissue on human skin cells was evaluated for viability, proliferation, and migration in vitro. Differentiation potential of stem cells treated with CM was monitored by AdipoRed staining and qualitative real-time polymerase chain reaction. Angiogenic potential of human endothelial cells treated with CM was tested via sprouting assay. RESULTS: The CM of adipose tissue significantly enhanced ASC proliferation (P < 0.01). Treatment with CM showed no inductive effect on ASC differentiation into adipocytes but, at the same time, significantly induced cell sprouting of endothelial cells (P < 0.001). We show for the first time that CM of adipose tissue is a potent inducer of proliferation of ASCs and angiogenesis, with comparable effects with those of stem cell-enriched CM. CONCLUSIONS: We suggest the use of the secretome of adipose tissue to produce CM for topical application on wounds, rather than working with adipose tissue or including the difficult process of enriching the patients' stem cells in vitro.

Osteopontin promotes aromatase expression and estradiol production in human adipocytes.

Breast and endometrial cancer are often estrogen dependent, and their incidence and mortality are increased by obesity in postmenopausal women. Osteopontin (OPN) is a cytokine strongly upregulated in adipose tissue (AT) in obesity. OPN function is potentiated by cleavage by matrix metalloproteinases (MMP). OPN and MMPs play a role in cancer development and are prognostic markers in breast cancer progression. While induction of the estrogen-synthesizing enzyme aromatase by TNFa and IL1 has been shown in preadipocytes, an impact of OPN on aromatase expression in AT has not been investigated yet. Gene expression was determined in AT samples of 21 morbidly obese and matched non-obese subjects. Primary human adipocytes were treated with full-length OPN or MMP-cleaved OPN (cOPN). Protein and mRNA expressions were analyzed from cell lysates, or cells were subsequently supplied with testosterone to determine estradiol production and for indirect co-culture with the estrogen-dependent MCF-7 cell line. Aromatase expression strongly correlated with gene expression of OPN and various MMPs in visceral and MMPs in subcutaneous AT, but not with TNFα expression in both tissues. In vitro, cOPN more effectively than full-length OPN upregulated aromatase mRNA in adipocytes and significantly increased aromatase protein level and estradiol production, leading to increased MCF-7 growth in indirect co-culture. OPN and MMPs are upregulated in AT in obesity, and MMP-cleaved OPN is particularly effective in inducing aromatase activity in human adipocytes. Thereby, obesity-induced OPN expression in AT may contribute to estradiol production and thus to the association of obesity with estrogen-dependent cancers.

Predisposing factors for candidemia in patients with major burns.

BACKGROUND: Despite advances in surgery and critical care, candidemia remains a significant cause of morbidity and mortality in patients with extensive burns. METHODS: A retrospective single-center cohort study was performed on 174 patients admitted to the Burn Intensive Care Unit of the General Hospital of Vienna (2007-2013). An AIC based model selection procedure for logistic regression models was utilized to identify factors associated with the presence of candidemia. RESULTS: Twenty (11%) patients developed candidemia on median day 16 after ICU admission associated with an increased overall mortality (30% versus 10%). Statistical analysis identified the following factors associated with proven candidemia: younger age (years) odds ratio (OR):0.96, 95% confidence interval (95% CI):0.92-1.0, female gender (reference male) OR:5.03, 95% CI:1.25-24.9, gastrointestinal (GI) complications requiring surgery (reference no GI complication) OR:20.37, 95% CI:4.25-125.8, non-gastrointestinal thromboembolic complications (reference no thromboembolic complication) OR:17.3, 95% CI:2.57-170.4 and inhalation trauma (reference no inhalation trauma) OR:7.96, 95% CI:1.4-48.4. CONCLUSIONS: Above-mentioned patient groups are at considerably high risk for candidemia and might benefit from a prophylactic antifungal therapy. Younger age as associated risk factor is likely to be the result of the fact that older patients with a great extent of burn body surface have a lower chance of survival compared to younger patients with a comparable TBSA.

Wharton's jelly mesenchymal stem cells promote wound healing and tissue regeneration.

Wound healing requires an orchestrated integration of complex biological and molecular events, which include inflammation, proliferation and remodeling. Wharton's jelly mesenchymal stem cells seem to promote wound healing and tissue repair. Wharton's jelly stem cells promote fibroblast proliferation and migration, accelerate re-epithelialization and promote overall wound repair by pcrine signaling. Wharton's jelly is an advantageous mesenchymal stem cell source because the harvest of this type of stem cells is not painful or invasive and because, beside their effect on wound healing, they seem to have a significant impact on the treatment of keloids. Furthermore, they led to better nerve regeneration, better neuroprotection and less inflammation.

Electrospun poly(ester-Urethane)- and poly(ester-Urethane-Urea) fleeces as promising tissue engineering scaffolds for adipose-derived stem cells.

An irreversible loss of subcutaneous adipose tissue in patients after tumor removal or deep dermal burns makes soft tissue engineering one of the most important challenges in biomedical research. The ideal scaffold for adipose tissue engineering has yet not been identified though biodegradable polymers gained an increasing interest during the last years. In the present study we synthesized two novel biodegradable polymers, poly(ε-caprolactone-co-urethane-co-urea) (PEUU) and poly[(L-lactide-co-ε-caprolactone)-co-(L-lysine ethyl ester diisocyanate)-block-oligo(ethylene glycol)-urethane] (PEU), containing different types of hydrolytically cleavable bondings. Solutions of the polymers at appropriate concentrations were used to fabricate fleeces by electrospinning. Ultrastructure, tensile properties, and degradation of the produced fleeces were evaluated. Adipose-derived stem cells (ASCs) were seeded on fleeces and morphology, viability, proliferation and differentiation were assessed. The biomaterials show fine micro- and nanostructures composed of fibers with diameters of about 0.5 to 1.3 µm. PEUU fleeces were more elastic, which might be favourable in soft tissue engineering, and degraded significantly slower compared to PEU. ASCs were able to adhere, proliferate and differentiate on both scaffolds. Morphology of the cells was slightly better on PEUU than on PEU showing a more physiological appearance. ASCs differentiated into the adipogenic lineage. Gene analysis of differentiated ASCs showed typical expression of adipogenetic markers such as PPARgamma and FABP4. Based on these results, PEUU and PEU meshes show a promising potential as scaffold materials in adipose tissue engineering.

Power assisted liposuction to obtain adipose-derived stem cells: impact on viability and differentiation to adipocytes in comparison to manual aspiration.

BACKGROUND: Adipose-derived stem cells (ASCs) play a key role in tissue engineering approaches and are probably of major importance in the context of autologous fat transfer. A number of different tools for harvesting ASCs-containing fat tissue have been established. Such devices should be easy to handle, time saving, low priced, safe and provide a high amount of viable ASCs in the aspirate. Power-assisted liposuction (PAL) has not yet been described in the literature as a tool for fat harvesting for lipotransfer. Aim of this study was to investigate ASCs' viability in fat tissue harvested using PAL versus manual aspiration (MA). METHODS: Fat tissue was obtained from 9 donors undergoing abdominoplasty. Samples were divided into two sections. Out of each section fat was harvested using either PAL or MA. Number of isolated ASCs was defined, proliferation rate was determined and cell viability was assessed by flow cytometry. The ability of isolated ASCs to differentiate into mature adipocytes was analyzed by gene marker expression. RESULTS: The number of viable ASCs and the proliferation rates did not significantly differ between PAL and MA but cells harvested using PAL showed significantly higher expression levels of differentiation markers adiponectin, GLUT4 and PPARg. CONCLUSION: Our results show that PAL is a feasible method for harvesting fat tissue containing viable ASCs. Quantity and quality of PAL-harvested ASC is similar or even better, respectively, compared to ASCs harvested by MA.

The use of a polylactide-based copolymer as a temporary skin substitute in deep dermal burns: 1-year follow-up results of a prospective clinical noninferiority trial.

Deep dermal burns can be covered with different kind of materials and techniques; one of them is a polylactide-based temporary skin substitute. The aim of this study was to intraindividually compare its 1-year outcome with the results obtained by use of autologous skin grafts in patients suffering from deep dermal burns. A prospective noninferiority trial was designed in order to assess skin quality and scar formation by use of subjective (Vancouver Scar Scale; Patient and Observer Scar Assessment Scale) and objective (noninvasive cutometry) burn scar assessment tools. All items of the Patient and Observer Scar Assessment Scale, except vascularity, were found to be noninferior in the areas covered with the temporary skin substitute vs. autologous skin. Results of objective scar evaluation showed comparable viscoelastic parameters without reaching noninferiority. Overall, the outcome of deep dermal burns covered with a polylactide-based temporary skin substitute revealed satisfactory results in terms of scar formation and skin quality as compared with autologous skin. This paper supports its use in deep dermal burns, where autologous skin donor sites require either to be reserved for coverage of full-thickness skin defects in severe burns or to be saved for reduction of additional morbidity in selected patient collectives.

Coenzyme Q10 does not enhance preadipocyte viability in an in vitro lipotransfer model.

BACKGROUND: Autologous fat is an attractive soft-tissue filler in plastic and reconstructive surgery. The success of the procedure relies strongly on the technique of transferring viable preadipocytes. Among other factors, preadipocyte viability is impaired by local anesthetics. Application of coenzyme Q10 is being performed by aesthetic plastic surgeons to enhance the success of lipotransfer. The aim of this study was to evaluate the effect of Q10 on preadipocyte viability with special regard to impairment after lidocaine treatment. METHODS: Preadipocytes were pretreated with coenzyme Q10 or vehicle control followed by incubation with lidocaine for 30 min. Viability and apoptosis were assessed by FACS analysis and Western blot. RESULTS: Coenzyme Q10 did not improve viability nor have any effect on investigated apoptosis parameters. Preadipocyte viability was reduced after lidocaine treatment. Surface binding of annexin V, cleavage of caspase-3, and abundance of subdiploid cells were not detectable though, suggesting that necrosis rather than apoptosis is the cause for reduced preadipocyte viability. CONCLUSION: Our results indicate that Q10 does not improve preadipocyte viability. Preadipocyte cell death induced by lidocaine is not caused by apoptosis but by necrosis, which cannot be prevented by coenzyme Q10. These findings should be taken into account when searching for solutions to improve preadipocyte viability in the context of soft tissue engineering and autologous fat transfer.

Adipose tissue engineering: three different approaches to seed preadipocytes on a collagen-elastin matrix.

BACKGROUND: Millions of plastic and reconstructive surgical procedures are performed each year to repair soft-tissue defects that result from significant burns, tumor resections, or congenital defects. Tissue-engineering strategies have been investigated to develop methods for generating soft-tissue. Preadipocytes represent a promising autologous cell source for adipose tissue engineering. These immature precursor cells, which are located between the mature adipocytes in the adipose tissue, are much more resistant to mechanical stress and ischemic conditions than mature adipocytes. To use preadipocytes for tissue-engineering purposes, cells were isolated from human adipose tissue and seeded onto scaffolds. Once processed, preadipocytes become subject to the human tissue act and require handling under much tighter regulations. Therefore, we intended to identify any influence caused by processing of preadipocytes prior to seeding on the reconstructed adipose tissue formation. MATERIAL AND METHOD: Human preadipocytes were isolated from subcutaneous adipose tissue obtained from discarded tissue during abdominoplasties of healthy men and women. Preadipocytes were divided into 3 groups. Cells of group I were seeded onto the scaffold directly after isolation, cells of group II were proliferated for 4 days before seeding, and cells of group III were proliferated and induced to differentiate before seeded onto the scaffold. A 3-dimensional scaffold (Matriderm, Dr. Otto Suwelack Skin and Health Care GmbH, Billerbeck, Germany) containing bovine collagen and elastin served as a carrier. Fourteen days after isolation, all scaffolds were histologically evaluated, using hematoxylin and eosin, anti-Ki-67 antibody, as well as immunofluorescence labeling with Pref-1 antibody (DLK (C-19), peroxisome proliferator-activated receptor gamma antibody, and DAPI (4',6-diamidino-2-phenylindole). RESULTS: Cells of all groups adhered to the scaffolds on day 21 after isolation. Cells of groups I (freshly isolated preadipocytes) and II (proliferated preadipocytes) adhered well and penetrated into deeper layers of the matrix. In group III (induced preadipocytes), penetration of cells was primarily observed to the surface area of the scaffold. DISCUSSION/CONCLUSION: : The collagen-elastin matrix serves as a useful scaffold for adipose tissue engineering. Freshly isolated preadipocytes as well as proliferated preadipocytes showed good penetration into deeper layers of the scaffold, whereas induced preadipocytes attached primarily to the surface of the matrix. We conclude that there might be different indications for each approach.