Viability of preadipocytes in vitro: the influence of local anesthetics and pH

Effects of epinephrine, lidocaine, and prilocaine on viability and differentiation capacity of human adipose stem cells

INTRODUCTION

Local anesthetics (LAs) are routinely administered in plastic and reconstructive surgery, e.g., as tumescent anesthesia adjunct in liposuction. Historically, these substances were assumed to act cytotoxically. Thus, the application of LA was avoided when handling adipose stem cells (ASCs). We recently determined that most LAs are not cytotoxic when ASCs are exposed to concentrations used for tumescent liposuction. However, there is limited information when combining LA with epinephrine and about the effects of prilocaine on ASCs.

METHODS

We analyzed the effects of prilocaine or lidocaine in co-exposure with epinephrine on the viability of primary human ASCs, i.e., proliferation, metabolic activity, and cytotoxicity, using crystal violet-staining, PrestoBlue®-, and WST-1 assay. We quantified the impact of short-term incubation of lidocaine and epinephrine on the differentiation of ASCs into the adipogenic, chondrogenic, and osteogenic lineage.

RESULTS

After 2 h, prilocaine (10 mM) significantly reduced metabolic activity and cell numbers, whereas lidocaine only inhibited metabolic activity. After 6 h, prilocaine (10 mM) and lidocaine significantly decreased metabolic activity as well as cell numbers. The application of high concentrations of epinephrine did not affect cell numbers but diminished metabolic activity. Combining lidocaine with epinephrine had no additional cytotoxic effect. Differentiation into the chondrogenic lineage was significantly inhibited by epinephrine.

CONCLUSIONS

Deducing from our data, neither lidocaine combined with epinephrine nor prilocaine has a cytotoxic impact on ASCs in vitro at concentrations equivalent to those in tumescent anesthesia and has no long-lasting effect on the differentiation capacity of ASCs into the osteogenic and adipogenic lineage.

Comprehensive Analysis of Local Anesthetics Affecting Adipose Stem Cells In Vitro

BACKGROUND

Adipose stem cells (ASCs) hold a great regenerative capacity because of their differentiation capability and their secretory activity. Thus, ASC survival is of great significance during perioperative harvesting. Various local anesthetics are commonly applied during fat grafting procedures. These substances are known to impair cellular viability, which would affect graft survival and final outcomes, but the exact extent of their impact on ASC biology is unknown.

METHODS

The authors analyzed the short- and long-term effects of lidocaine, mepivacaine, ropivacaine, and bupivacaine at increasing concentrations (0.1 to 10 mM) on primary human ASC proliferation and metabolic activity. Trilinear differentiation was assessed by oil red O stain (adipogenesis), safranin O (chondrogenesis), and cresolphthalein (osteogenesis) labeling. In supernatants, cytokine [interleukin (IL)-6/IL-8, vascular endothelial growth factor, hepatocyte growth factor] secretion was analyzed by enzyme-linked immunosorbent assay.

RESULTS

Bupivacaine at greater than 100 µM demonstrated the strongest anti proliferative effects, whereas lidocaine and ropivacaine did not affect cell numbers. Mepivacaine evoked reciprocal results regarding cell count at greater than 1 mM. Each compound impaired trilinear differentiation. Secretion of hepatocyte growth factor and IL-8 was reduced significantly by local anesthetic exposure; levels were restored after substances were washed out.

CONCLUSIONS

In vitro data show that lidocaine, mepivacaine, and ropivacaine could be applied at concentrations of 1 to 10 mM without affecting ASC survival. In contrast, bupivacaine at concentrations greater than 100 µM should be administered with great caution. The differentiation of ASCs and the ASC's secretome might already be decreased by each local anesthetic at 1 mM.

CLINICAL RELEVANCE STATEMENT

The authors' experimental data can be of great significance to the clinical practice, as local anesthetics are routinely administered during liposuction as a tumescent anesthesia adjunct.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Fat Grafting: Basic Science, Techniques, and Patient Management

In this review, a summary of the rich history of autologous fat grafting is provided, and a comprehensive summary of the science and theory behind autologous adipocyte transplantation, as well as the techniques commonly used is described. These include recipient site preparation, harvesting, processing, and engraftment. In addition, important considerations for preoperative and postoperative management are discussed to maximize graft retention. Special considerations in grafting to the breast, face, and buttocks are also summarized.

UK Guidelines for Lipomodelling of the Breast on behalf of Plastic, Reconstructive and Aesthetic Surgery and Association of Breast Surgery Expert Advisory Group

Lipomodelling has become increasingly popular for reconstructive, aesthetic and therapeutic indications. The guidelines summarise available evidence for indications, training, technique, audit and outcomes in lipomodelling and also highlight areas for further research.

Surgical Decision Making in Autologous Fat Grafting: An Evidence-Based Review of Techniques to Maximize Fat Survival

Autologous fat grafting is an important tool in plastic surgery and is widely used for a variety of applications, both aesthetic and reconstructive. Despite an ever-increasing list of indications and extensive research over many years into improving outcomes, fat grafting remains plagued by incomplete and often unpredictable graft survival. Decisions made at each stage of surgery can potentially contribute to ultimate success, including donor site selection and preparation, fat harvest, processing, and purification of lipoaspirate, recipient site preparation, and delivery of harvested fat to the recipient site. In this review, we examine the evidence for and against proposed techniques at each stage of fat grafting. Areas of consensus identified include use of larger harvesting and grafting cannulas and slow injection speeds to limit cell damage due to shearing forces, grafting techniques emphasizing dispersion of fat throughout the tissue with avoidance of graft pooling, and minimizing exposure of the lipoaspirate to the environment during processing. Safety considerations include use of blunt-tipped needles or cannulas to avoid inadvertent intravascular injection as well as awareness of cannula position and avoidance of danger zones such as the subgluteal venous plexus. We believe that using the evidence to guide surgical decision-making is the key to maximizing fat grafting success. Level of Evidence: 4.

Effect of local anesthetics on viability and differentiation of various adult stem/progenitor cells

BACKGROUND

Local anesthetics (LAs) are widely used to control pain during various clinical treatments. One of the side effects of LAs, cytotoxicity, has been investigated in various cells including stem/progenitor cells. However, our understanding of the effects of LAs on the differentiation capacity of stem/progenitor cells still remains limited. Therefore, a comparative study was conducted to investigate the effects of multiple LAs on viability and multi-lineage differentiation of stem/progenitor cells that originated from various adult tissues.

METHOD

Multiple types of stem/progenitor cells, including bone marrow mesenchymal stem/progenitor cells (MSCs), dental pulp stem/progenitor cells (DPSCs), periodontal ligament stem/progenitor cells (PDLSCs), and tendon-derived stem/progenitor cells, were either obtained from a commercial provider or isolated from adult human donors. Lidocaine (LD) and bupivacaine (BP) at various doses (1×, 0.75×, 0.5×, and 0.25× of each physiological dose) were applied to the different stem/progenitor cells for an hour, followed by induction of fibrogenic, chondrogenic, osteogenic, and adipogenic differentiation. Live/dead and MTT assays were performed at 24 h after the LD or BP treatment. At 2 weeks, qRT-PCR was conducted to evaluate the gene expressions associated with differentiation. After 4 weeks, multiple biochemical staining was performed to evaluate matrix deposition.

RESULTS

At 24 h after LD or BP treatment, 1× and 0.75× physiological doses of LD and BP showed significant cytotoxicity in all the tested adult stem/progenitor cells. At 0.5×, BP resulted in higher viability than the same dose LD, with variance between cell types. Overall, the gene expressions associated with fibrogenic, chondrogenic, osteogenic, and adipogenic differentiation were attenuated in LD or BP pre-treated stem/progenitor cells, with notable dose-effect and dependence on types. In contrast, certain doses of LD and/or BP were found to increase specific gene expression, depending on the cell types.

CONCLUSION

Our data suggest that LAs such as LD and BP affect not only the viability but also the differentiation capacity of adult stem/progenitor cells from various anatomical sites. This study sheds light on stem cell applications for tissue regeneration in which isolation and transplantation of stem cells frequently involve LA administration.

International Expert Panel Consensus on Fat Grafting of the Breast

Background

Autologous fat grafting has broad applications in reconstructive and aesthetic breast surgery as a natural filler and for its regenerative purposes. Despite the widespread use of fat grafting, there remains no shared consensus on what constitutes the optimal fat grafting technique and its oncological safety. For this reason, the authors of this study have organized a Survey and an International Consensus Conference that was held at the Aesthetic Breast Meeting in Milan (December 15, 2018).

Methods

All studies on fat grafting, both for breast aesthetic and reconstructive purposes, were electronically screened. The literature review led to 17 "key questions" that were used for the Survey. The authors prepared a set of 10 "key statements" that have been discussed in a dedicated face-to-face session during the meeting.

Results

The 10 key statements addressed all the most debated topics on fat grafting of the breast. Levels of evidence for the key statements ranged from III to IV with 2 statements (20%) supported by a level of evidence III and 6 statements (60%) by level of evidence IV. Overall consensus was reached for 2 statements (20%) with >75% agreement reached for 7 statements.

Conclusions

The survey demonstrated a diversity of opinion and attitude among the panelists with regard to technique. Clear recommendations for evidence-based clinical practice for fat grafting use both in aesthetic and reconstructive breast surgery could not be defined due to the scarcity of level 1 or 2 studies.

Autologous fat grafting: Latest insights

A recent rise in the use of autologous fat transfer for soft tissue augmentation has paralleled the increasing popularity of liposuction body contouring. This creates a readily available and inexpensive product for lipografting, which is the application of lipoaspirated material. Consistent scientific proof about the long-term viability of the transferred fat is not available. Clinically, there is a reabsorption rate which has been reported to range from 20 to 90%. Results can be unpredictable with overcorrection and regular need for additional interventions. In this review, adipogenesis physiology and the adipogenic cascade from adipose-derived stem cells to adult adipocytes is extensively described to determine various procedures involved in the fat grafting technique. Variables in structure and physiology, adipose tissue harvesting- and processing techniques, and the preservation of fat grafts are taken into account to collect reproducible scientific data to establish standard in vitro and in vivo models for experimental fat grafting. Adequate histological staining for fat tissue, immunohistochemistry and viability assays should be universally used in experiments to be able to produce comparative results. By analysis of the applied methods and comparison to similar experiments, a conclusion concerning the ideal technique to improve clinical outcome is proposed.

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Adipogenic physiology is described to determine various procedures involved in the fat grafting technique.

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Clinical studies on fat grafting have confirmed an unpredictable result.

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After analysis of the literature and despite attempts to eliminate confounding factors, on every step of the fat transfer technique a number of studies with conflicting results exist.

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Adequate histological staining for fat tissue, immunohistochemistry and viability assays should be universally used in experiments to be able to produce comparative results.

Literature Review to Optimize the Autologous Fat Transplantation Procedure and Recent Technologies to Improve Graft Viability and Overall Outcome: A Systematic and Retrospective Analytic Approach

OBJECTIVE

Investigation and evaluation of the current methods and steps of autologous fat transplantation to optimize the viability of fat grafts and procedure outcome in quest of a more standardized protocol.

METHODS

A thorough literature search was performed across the CNKI, Wan Fang, PubMed, Ovid and EMBASE databases from the year 1970 to December 2014, collecting and classifying all of the autologous fat transplantation-related reports and articles, and after screening, a critical retrospective analysis was performed on the included data.

RESULTS

A total of 65 articles were included in the study. However, there were limited numbers of cases dealing with procedure-related steps such as the selection of donor sites, fat acquisition, graft treatment and methodology of transplant, resulting in a significant lack of evidence support, furthermore urging the need for more standardized protocol for the steps of autologous fat transplant to improve graft viability and overall outcome while decreasing procedure-related morbidity.

CONCLUSION

No good evidence was obtained to optimize the donor site, acquisition, processing and transplantation steps of the whole process of autologous fat transplantation. Tissue engineering and stem cell research have the potential to revolutionize the future of reconstructive surgery by replacing tissue, obviating the need for donor site morbidity. However, the use of stem cell therapies to expand and grow tissue for reconstruction must occur in the context of risk management. Balancing ease of harvest with yield and efficacy has been a delicate and often difficult trade-off which has prompted the scientific community to investigate alternative sources. However, there is much hope in the evaluation and implementation of multimodality approaches for autologous fat transplant, including thriving technologies such as ultrasound-assisted, water jet-assisted, nanotechnology-assisted liposuction in combination with revolutionary fat treatment technologies such as the VASER system.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Exposure to Tumescent Solution Significantly Increases Phosphorylation of Perilipin in Adipocytes

BACKGROUND

Lidocaine and epinephrine could potentially decrease adipocyte viability, but these effects have not been substantiated. The phosphorylation status of perilipin in adipocytes may be predictive of cell viability. Perilipin coats lipid droplets and restricts access of lipases; phospho-perilipin lacks this protective function.

OBJECTIVES

The authors investigated the effects of tumescent solution containing lidocaine and epinephrine on the phosphorylation status of perilipin in adipocytes.

METHODS

In this in vitro study, lipoaspirates were collected before and after tumescence from 15 women who underwent abdominoplasty. Fat samples were fixed, sectioned, and stained for histologic and immunohistochemical analyses. Relative phosphorylation of perilipin was inferred from pixel intensities of immunostained adipocytes observed with confocal microscopy.

RESULTS

For adipocytes collected before tumescent infiltration, 10.08% of total perilipin was phosphorylated. In contrast, 30.62% of total perilipin was phosphorylated for adipocytes collected from tumescent tissue (P < .01).

CONCLUSIONS

The tumescent technique increases the relative phosphorylation of perilipin in adipocytes, making these cells more vulnerable to lipolysis. Tumescent solution applied for analgesia or hemostasis of the donor site should contain the lowest possible concentrations of lidocaine and epinephrine. LEVEL OF EVIDENCE 5.

Adipose Derived-Mesenchymal Stem Cells Viability and Differentiating Features for Orthopaedic Reparative Applications: Banking of Adipose Tissue

Osteoarthritis is characterized by loss of articular cartilage also due to reduced chondrogenic activity of mesenchymal stem cells (MSCs) from patients. Adipose tissue is an attractive source of MSCs (ATD-MSCs), representing an effective tool for reparative medicine, particularly for treatment of osteoarthritis, due to their chondrogenic and osteogenic differentiation capability. The treatment of symptomatic knee arthritis with ATD-MSCs proved effective with a single infusion, but multiple infusions could be also more efficacious. Here we studied some crucial aspects of adipose tissue banking procedures, evaluating ATD-MSCs viability, and differentiation capability after cryopreservation, to guarantee the quality of the tissue for multiple infusions. We reported that the presence of local anesthetic during lipoaspiration negatively affects cell viability of cryopreserved adipose tissue and cell growth of ATD-MSCs in culture. We observed that DMSO guarantees a faster growth of ATD-MSCs in culture than trehalose. At last, ATD-MSCs derived from fresh and cryopreserved samples at -80°C and -196°C showed viability and differentiation ability comparable to fresh samples. These data indicate that cryopreservation of adipose tissue at -80°C and -196°C is equivalent and preserves the content of ATD-MSCs in Stromal Vascular Fraction (SVF), guaranteeing the differentiation ability of ATD-MSCs.

The Effects of Fat Harvesting and Preparation, Air Exposure, Obesity, and Stem Cell Enrichment on Adipocyte Viability Prior to Graft Transplantation

BACKGROUND

Adipocyte viability is affected by fat preparation and processing methods, but rigorous and objective studies of these relationships are lacking.

OBJECTIVES

The authors conducted a comprehensive evaluation of variables affecting adipocyte viability prior to injection of fat at the recipient site.

METHODS

Lipoaspirates from 48 patients were processed by high or low vacuum pressure, decantation, electric or manual centrifugation, concentration with cotton gauze, washing, repeated syringe transfer, exposure to lidocaine, and exposure to air. The effects of these variables on adipocyte viability in vitro were ascertained with the MTT assay. The influences of patient obesity (ie, a body mass index [BMI] >30 kg/m²) and enrichment with stem cells on adipocyte viability also were determined.

RESULTS

High vacuum pressure decreased adipocyte viability. Decantation yielded the highest cell viability, followed by washing, concentration with cotton gauze, and centrifugation. Exposure to concentrated lidocaine ambient air exposure, and transfer between syringes significantly decreased viability. Patient obesity was predictive of lower adipocyte viability regardless of processing method, whereas stem cell enrichment significantly improved viability (P < .0001).

CONCLUSIONS

To maximize adipocyte viability, fat should be obtained with dilute local anesthetics and low vacuum pressure, and the lipoaspirate should be maintained in a closed system. To clear cellular debris and blood, the lipoaspirate should be prepared by washing, and the fat should be enriched with adipose stem cells. Decreased adipocyte viability should be expected when fat is harvested from patients with high BMIs.

Breast Augmentation by Water-Jet Assisted Autologous Fat Grafting: A Report of 300 Operations

Background  The BEAULI -method (Breast Augmentation by Lipotransfer) is available for extraction and processing of large transplantable fat quantities. The aim of this work is to describe the surgical technique precisely and reproducibly and to provide an overview of the autologous fat transfer based on surgical experience.

Method  The author performed 300 autologous fat transplantations on 254 women between September 3, 2010, and May 13, 2015. Patients desiring moderate volume increase, fuller and firmer breasts, as well as an optimization of the silhouette, ideally with the concurrent desire of the correction of unwanted fat deposits, were selected. The fat was extracted via water-jet assisted liposuction (Body-jet, Human Med AG, Schwerin, Germany), and the fat cells were subsequently separated with the Lipocollector ^® (Human Med AG, Schwerin, Germany).

Results  The results were assessed with a control exam and photo comparison and were based on the responses on a questionnaire. Overall, 35.9% of the patients defined the result as very good, 38.6% as good, 22.4% as satisfactory, and 3.1% as poor.

Conclusion  This study shows that the autologous fat cell transplantation into the female breast via water-jet assisted liposuction achieves a moderate and harmoniously appearing breast volume enlargement as well as contour improvement. Further studies with more cases and longer observation periods over several years could contribute to improving the method of the autologous fat transfer regarding the grow-in rate, efficiency, and safety.

Adipose-Derived Stem Cells: New Treatment for Wound Healing?

Emerging evidence has shown that adipose tissue is the richest and most accessible source of mesenchymal stem cells. Many different therapies for chronic wounds exist with varying success rates. The capacity of adipose-derived stem cells (ASCs) to promote angiogenesis, secrete growth factors, regulate the inflammatory process, and differentiate into multiple cell types makes them a potential ideal therapy for chronic wounds. The aim of this article was to review all preclinical trials using ASCs in problem wound models. A systematic search was performed and 12 studies were found where different chronic wound models across different animals were treated with ASCs. Different ASC sources and delivery methods were used in the described studies. Studies demonstrated improved wound healing with utilization of ASC, and this treatment modality has so far shown great potential. However, more preclinical studies and large-scale clinical trials are needed to show if the emerging therapy can satisfy expectations.

Fat grafting and breast reconstruction: tips for ensuring predictability

Autologous fat grafting is widely used in breast surgery to refine and optimize aesthetic outcomes. Despite its widespread use, obtaining predictable, reliable, and consistent outcomes remains a significant challenge and is influenced by the technique used for procurement, processing, and placement of the fat. At present, there is no published consensus on the optimal technique. The purpose of this article is to review current techniques at each stage of fat grafting and provide tips on best practices based on the published literature as well as our extensive clinical experience.

Characterization of adipose tissue for autologous fat grafting

Fat grafting is a common procedure in aesthetic and reconstructive plastic surgery, but variable graft retention limits its utility. Unpredictable clinical outcomes with fat grafting can be explained in part by the lack of standardized protocols for harvesting, processing, and transplanting adipose tissue (AT). Historically, plastic surgeons have relied on trial and error and their clinical experience to develop fat grafting protocols. Optimization of fat grafting protocols requires systematic assessment of the impact that key variables have on the quality of the AT preparation at each step of the procedure. In this article, we review recent findings regarding the composition and quality of AT prepared for fat grafting and the strengths and limitations of existing AT characterization assays. We discuss the need for an assessment of the viability of intact AT (ie, conventionally harvested AT that has not been disrupted further) by means of an operator-independent, quantitative assay that can be performed in real time and generates reproducible data. Promising assays for the characterization of cell product quality have been developed for other therapeutic applications, such as transplantation of pancreatic islet cells. The development or adaptation of a gold-standard assay to determine the quality of an AT preparation may help to standardize fat grafting protocols and improve clinical outcomes.

Stem cells show promising results for lymphoedema treatment--a literature review

Lymphoedema is a debilitating condition, manifesting in excess lymphatic fluid and swelling of subcutaneous tissues. Lymphoedema is as of yet still an incurable condition and current treatment modalities are not satisfactory. The capacity of mesenchymal stem cells to promote angiogenesis, secrete growth factors, regulate the inflammatory process, and differentiate into multiple cell types make them a potential ideal therapy for lymphoedema. Adipose tissue is the richest and most accessible source of mesenchymal stem cells and they can be harvested, isolated, and used for therapy in a single stage procedure as an autologous treatment. The aim of this paper was to review all studies using mesenchymal stem cells for lymphoedema treatment with a special focus on the potential use of adipose-derived stem cells. A systematic search was performed and five preclinical and two clinical studies were found. Different stem cell sources and lymphoedema models were used in the described studies. Most studies showed a decrease in lymphoedema and an increased lymphangiogenesis when treated with stem cells and this treatment modality has so far shown great potential. The present studies are, however, subject to bias and more preclinical studies and large-scale high quality clinical trials are needed to show if this emerging therapy can satisfy expectations.

Acute adipocyte viability after third-generation ultrasound-assisted liposuction

BACKGROUND

Although clinical evidence of successful autologous fat transfer (AFT) using third-generation ultrasound-assisted liposuction (UAL) is readily available, no study has quantified adipocyte viability using standardized methods.

OBJECTIVES

The authors assess acute adipocyte viability following fat aspiration as a first step in determining the overall efficacy of using third-generation UAL for AFT.

METHODS

Lipoaspirate samples were collected from patients who underwent elective liposuction procedures at multiple surgery centers. Patients with a history of bleeding disorders, diabetes, human immunodeficiency virus, or lipoatrophy disorders were excluded. The UAL system (VASER; Sound Surgical Technologies, Inc, Louisville, Colorado) was set at 60% amplitude in pulsed mode with vacuum aspiration of 15 in Hg or less. Laboratory analysis included free lipid volume, viability via lipolysis and propidium iodide staining, and cytological analysis, including cell surface protein examination and hematoxylin and eosin staining.

RESULTS

The lipolysis assay revealed metabolically active adipocytes with a mean (SD) correlative viability of 85.1% (11%). Direct measures of acute viability via propidium iodide staining resulted in a mean (SD) viability measure of 88.7% (3.5%). Both mean values are within the historical range reported from syringe and vacuum-assisted lipoaspiration. Aqueous and lipid contents were favorably reduced after washing and filtering (Puregraft system; Cytori Therapeutics, Inc, San Diego, California). Cellular phenotypes identified were primarily white blood cells or vascular endothelial and vascular associated cells.

CONCLUSIONS

Adipose tissue acquired via third-generation UAL is viable at harvest and is potentially a suitable source for autologous fat grafts. These results confirm reported clinical successes utilizing third-generation ultrasound lipoaspirate for AFT.

New insights into lidocaine and adrenaline effects on human adipose stem cells

BACKGROUND

Adipose stem cells have gained great interest in plastic and reconstructive surgery with their ability to improve engraftment after fat transfer for soft tissue filling. It is therefore essential to know the effect of the drugs commonly used during the lipoaspiration procedure, such as lidocaine and adrenaline. Indeed, these drugs are infiltrated at the fat donor site for local anesthesia and for reduction of bleeding. This study analyzed the effects of these drugs on the viability of adipose-derived stem cells and on their inflammatory status.

METHODS

Adipose-derived stem cells from lipoaspirates were grown in culture before being treated with different clinical doses of lidocaine at different times of exposure (1-24 h), and with adrenaline (1 μg/mL). Cytotoxicity was measured by lactate dehydrogenase assay and by flow cytometry with annexin V/propidium iodide staining. In parallel, the secretion of the proinflammatory cytokines tumor necrosis factor-alpha (TNFα), interleukin-6 (IL-6), and monocyte chemotactic protein-1 (MCP-1) was tested by enzyme-linked immunoassay.

RESULTS

Lidocaine affected cell viability after 24 h, even when the cells were exposed for only 1 or 2 h. Apoptosis was not involved in lidocaine cytotoxicity. Regarding inflammation, no TNFα was produced, and lidocaine decreased the levels of IL-6 and MCP-1 in a dose-dependent manner. In contrast, adrenaline did not influence cell viability or cytokine secretions.

CONCLUSIONS

Adipose tissue should be handled appropriately to remove lidocaine and adrenaline, with such procedures as washing and centrifugation. This study provides new insights into the use of lidocaine and adrenaline for fat transfer or stem cell isolation from lipoaspirates.

LEVEL OF EVIDENCE II

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

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.

Automated isolation and processing of adipose-derived stem and regenerative cells

The popularity of nonhematopoietic, adult tissue-derived stem and progenitor cells for use as a cellular research tool, and ultimately as a clinical therapeutic, has increased exponentially over the past decade. Almost all adult-derived stem/progenitor cells (autologous and allogeneic), with one exception, require at least some ex vivo expansion or further manipulation prior to use to satisfy efficacy and safety requirements for preclinical or clinical use. The principal reason is the relatively low frequency of these therapeutically valuable cells within any given adult tissue, except for adipose tissue, which has been shown to have at least two log greater concentrations of these progenitor cells. Therefore, use of autologous adipose-derived cells as both a research tool and cell therapeutic is feasible and has been shown to be both safe and efficacious in preclinical and clinical models of injury and disease. The development and utilization of automated processes and instrumentation such as Cytori Therapeutics' Celution® System to reduce variability and increase quality of the recovered cells is requisite for clinical use and preferred by basic researchers. Here, use of an automated, closed processing platform for isolation and concentration of adipose-derived stem and regenerative cells is described, including a profile of the isolated cells immediately prior to use, and commonly used methods to quantify and qualitatively assess the recovered cells.

Local anesthetics have a major impact on viability of preadipocytes and their differentiation into adipocytes

BACKGROUND

Autologous fat transplantation is a well-established technique in surgery. Moreover, the use of preadipocytes in soft-tissue engineering is currently being intensely investigated. Current efforts focus on identifying maneuvers that may minimize resorption and provide predictable late results. The aim of this study was to investigate the influence of different local anesthetics frequently used in clinical practice on the viability of preadipocytes and their ability to differentiate into adipocytes.

METHODS

Human preadipocytes were isolated from subcutaneous adipose tissue of 15 patients and treated with bupivacaine, mepivacaine, ropivacaine, articaine/epinephrine, and lidocaine for 30 minutes. Viability was determined directly after treatment and during the ensuing cultivation. Differentiation of preadipocytes was determined by expression of the adipocyte marker adiponectin.

RESULTS

Although the immediate effects of mepivacaine and ropivacaine were only moderate, treatment with articaine/epinephrine and lidocaine strongly impaired preadipocyte viability. Cells normally attached to the culture dishes and proliferated irrespective of the previous treatment. During long-term cultivation, articaine/epinephrine-treated cell viability decreased markedly, whereas other local anesthetics had no impact. Despite normal phenotypic appearance of cells treated with bupivacaine, mepivacaine, ropivacaine, and lidocaine, all local anesthetics markedly impaired adipocyte differentiation as determined by adiponectin expression.

CONCLUSIONS

The authors' results show that there is a marked influence of local anesthetics not only on the quantity but also on the quality of viable preadipocytes as determined by their ability to differentiate into mature adipocytes. Therefore, these results should be considered in the context of autologous fat transfer and soft-tissue engineering.