Lipo layering of autologous fat: an improved technique with promising results

Volume loss versus gravity: new concepts in facial aging

PURPOSE OF REVIEW

The earliest techniques of facial rejuvenation have been continuously adapted to reflect changes in the understanding of the aging face. Significant, paradigm-shifting advances in this understanding have been made in recent years which have allowed application of specific therapeutic modalities, resulting in dramatically improved results over those achieved with traditional facial rejuvenation.

RECENT FINDINGS

Pioneering work by several authors has shown that gravity is not the sole determinant of the aging face. These authors have demonstrated that volume loss, including that of soft tissue and bone, is at least equally important in the pathogenesis of the stigmata of aging. Rejuvenative techniques developed to reverse these atrophic changes have exhibited outstanding results. The consequence is an increasing emphasis on the use of volume restoration procedures to address the aging face.

SUMMARY

Recent improvements in the understanding of the facial aging process have brought about newly refined techniques for facial rejuvenation, ushering in a new era of plastic surgery for the aging face which is being manifested by increasingly natural results.

Cell-assisted lipotransfer: supportive use of human adipose-derived cells for soft tissue augmentation with lipoinjection

Injective transfer of autologous aspirated fat is a popular option for soft tissue augmentation, but several issues require attention, including unpredictability and a low survival rate due to partial necrosis. In this study, histologic features and yield of adipose-derived stromal (stem) cells (ASCs) were compared between human aspirated fat and excised whole fat. Aspirated fat contained fewer large vascular structures, and ASC yield was lower in aspirated fat. Aspirated fat was transplanted subcutaneously into severe combined immunodeficiency mice with (cell-assisted lipotransfer; CAL) or without (non-CAL) vascular stromal fractions containing ASCs isolated from adipose tissue. The CAL fat survived better (35% larger on average) than non-CAL fat, and microvasculature was detected more prominently in CAL fat, especially in the outer layers. DiI-labeled vascular stromal fraction cells were found between adipocytes and in the connective tissue in CAL fat, and some of these cells were immunopositive for von Willebrand factor, suggesting differentiation into vascular endothelial cells. Another experiment that used vascular stromal fractions taken from green fluorescent protein rats also suggested that ASCs differentiated into vascular endothelial cells and contributed to neoangiogenesis in the acute phase of transplantation. These findings may partly explain why transplanted aspirated fat does not survive well and suggest clinical potential of the CAL method for soft tissue augmentation.

An Alternative Method for Harvest and Processing Fat Grafts: An In Vitro Study of Cell Viability and Survival

BACKGROUND

Adipocyte viability has been emphasized as essential for fat graft survival. There is no universal agreement on the methodology for handling fat grafts.

OBJECTIVE

Two different methods of fat harvesting and techniques of tissue processing were compared by assessing cell viability, damage, and growth in vitro.

METHOD

Fat was harvested from Zucker rats (n = 5) using (1) a 3-mm liposuction cannula with a 60-cc syringe (right side) or (2) a 2-mm blunt needle with a 10-cc syringe adapted to a fine-needle aspiration apparatus (left side). Tissues were then processed by decantation or cotton towel drying. Five samples for each of the four techniques were studied. Fat samples were processed for culture, and adipocytes and preadipocytes were plated in culture medium and expanded in vitro. Cell viability was assessed using cell counts, the MTT proliferation assay, G3PDH activity, and Oil Red O stain.

RESULTS

Method 1 exerted significantly higher pressure (p = 0.009) than method 2 (643 +/- 2.5 versus 537 +/- 13.6 mm Hg). A larger oil layer was apparent with method 1 (1.11 +/- 0.29 g) than with method 2 (0.56 +/- 0.28 g). In addition, the highest number of viable preadipocytes was obtained using method 2B (p = 0.017). In culture, preadipocytes plated in 4F differentiation medium started to differentiate after 1 week, while those in Dulbecco's modified Eagle's medium/F12 with serum proliferated but did not differentiate. Mature adipocytes in adipogenic medium dedifferentiated and later redifferentiated into fat cells.

CONCLUSIONS

Fat viability was better when fat was harvested by fine-needle aspiration. The plasticity of mature adipocytes and preadipocytes in vitro suggested that both might be involved in fat graft integration.

Biomaterials approach to expand and direct differentiation of stem cells

Stem cells play increasingly prominent roles in tissue engineering and regenerative medicine. Pluripotent embryonic stem (ES) cells theoretically allow every cell type in the body to be regenerated. Adult stem cells have also been identified and isolated from every major tissue and organ, some possessing apparent pluripotency comparable to that of ES cells. However, a major limitation in the translation of stem cell technologies to clinical applications is the supply of cells. Advances in biomaterials engineering and scaffold fabrication enable the development of ex vivo cell expansion systems to address this limitation. Progress in biomaterial design has also allowed directed differentiation of stem cells into specific lineages. In addition to delivering biochemical cues, various technologies have been developed to introduce micro- and nano-scale features onto culture surfaces to enable the study of stem cell responses to topographical cues. Knowledge gained from these studies portends the alteration of stem cell fate in the absence of biological factors, which would be valuable in the engineering of complex organs comprising multiple cell types. Biomaterials may also play an immunoprotective role by minimizing host immunoreactivity toward transplanted cells or engineered grafts.

Structural fat grafting: more than a permanent filler

Grafted fat has many attributes of an ideal filler, but the results, like those of any procedure, are technique dependent. Fat grafting remains shrouded in the stigma of variable results experienced by most plastic surgeons when they first graft fat. However, many who originally reported failure eventually report success after altering their methods of harvesting, refinement, and placement. Many surgeons have refined their techniques to obtain long-term survival and volume replacement with grafted fat. They have observed that transplanted fat not only adjusts facial and body proportion but also improves surrounding tissues into which the fat is placed. They have noted not only the improvement in the quality of aging skin and scars but also a remarkable improvement in conditions such as radiation damage, chronic ulceration, breast capsular contracture, and damaged vocal cords. The mechanism of fat graft survival is not clear, and the role of adipose-derived stem cells and preadipocytes in fat survival remains to be determined. Early research has indicated the possible involvement of more undifferentiated cells in some of the observed effects of fat grafting on surrounding tissues. Of particular interest is the research that has pointed to the use of stem cells to repair and even to become bone, cartilage, muscle, blood vessels, nerves, and skin. Further studies are essential to understand grafted fat tissue.

Facial Augmentation With Structural Fat Grafting

Fat grafting through a blunt cannula has been used by plastic surgeons for altering facial contours for 100 years. Autologous tissue is completely biocompatible and is usually the safest choice for altering facial volume or contours. Fat grafts can be placed in such a fashion that they are long lasting, completely integrated, and natural appearing. Only in the past 20 years have advances in techniques and instrumentation allowed us to obtain predictable results that make fat grafting a viable option for soft tissue augmentation. Our understanding of aging and methods of rejuvenation have developed also. We now approach rejuvenation and adjustment of facial proportion with a better understanding of the need for the restoration or adjustment of facial volume.

Cosmetic Procedures for the Aging Face

As the United States' population continues to age and as cosmetic procedures have become more accepted, adults from all age groups and socioeconomic brackets are seeking improvement in facial aging. Ideal correction includes improvement in the quality of skin, improvement in wrinkles, correction of soft tissue descent, removal of skin excess, and volume restoration. The physiologic rather than the chronologic age is the most important factor in determining the advisability of cosmetic surgery in elderly people. In addition to traditional cosmetic surgery procedures, the elderly population is amenable to several shortcuts, minimizing operative time and post-operative recovery. These can be performed alone or in combination with traditional procedures, improving the stigmata of facial aging and enhancing quality of life.

La greffe de tissu adipeux : mythe ou réalité scientifique. Lecture critique de la littérature

Fat grafting is an old technique. Since its first description in 1893, fat was used in a lot of indications. After more then a century of evolution, there is still no commonly accepted standard method of fat transfer by all the authors. On the contrary, many different techniques have been described in the literature with the only aim of reducing resorption of the transferred fat. Today the main inconvenient of fat grafting remains the partial resorption the transferred tissue. After a review of the literature of the various technique of fat transfer presented according to their chronology in the operative procedure, we have observed that the techniques developed by certain authors are the opposite of the techniques developed by others. This shows the lack of rigorous work concerning the fat transfer. Whether they are experimental or clinical, in most of these studies, we can find at least one skew which could have influence the results and the conclusion of these studies. A critical revue of the literature offers the opportunity to reconsider the actual bases of fat transfer. The use of an objective way of quantifying the volumes in clinical practice could permit the comparison of different studies in the future.

Autologous Human Fat Grafting: Effect of Harvesting and Preparation Techniques on Adipocyte Graft Survival

BACKGROUND

Autogenous fat transfer with lipoinjection for soft-tissue augmentation is a commonly used technique without a universally accepted approach. The high percentage and variable amount of fat resorption reduce the clinical efficacy of this procedure and often result in the need for further grafting. The purposes of this study were to evaluate the effect of different harvesting and preparation techniques on human fat tissue viability and to determine fat tissue viability rates among the different fat preparations transplanted into a severe combined immune deficiency mouse model at 3 months.

METHODS

Using standard liposuction and syringe aspiration, fat was removed from patients (n = 3) undergoing elective body contouring. Tissue was prepared by six different combinations of centrifugation and/or washing the cells with lactated Ringer's solution or normal saline. Metabolic activities of fat cell viability were monitored to assess overall cell viability. To analyze viability over 3 months, freshly harvested tissue specimens (minimum n = 5) were prepared by a combination of various procedures (wash, centrifugation, and different solutions) and subsequently injected under the dorsal flank skin of severe combined immune deficiency mice in two experiments. Mice were monitored for 12 weeks and the fat xenografts were removed for mass and histological evaluations.

RESULTS

Metabolic analyses showed improved cell viability in tissue specimens undergoing minimal manipulation. No significant differences in fat cell viability, as assessed by graft weight maintenance or histologic evaluations, were observed with regard to harvesting or preparation techniques.

CONCLUSIONS

Improved viability of freshly harvested but untreated fat specimens may be expected as compared with grafts that have undergone additional manipulations. No unique combination of preparation or harvesting techniques appeared to be more advantageous on transplanted fat grafts at 3 months. This study also demonstrated a reliable animal model for future investigation into examining novel applications for augmenting fat graft survival.

Fat injection to correct contour deformities in the reconstructed breast

BACKGROUND

A ten-year, single-surgeon study of 37 patients from 1993 to 2003 who underwent fat injections to improve contour deformities in their reconstructed breasts was reviewed.

METHODS

Fat was harvested from elsewhere in the body using a low-pressure syringe lipoaspiration system, washed gently with saline, and injected into depressions along the margins of reconstructed breasts. Blinded physician observers judged preoperative and postoperative photographs of breasts injected with fat and categorized the degree of contour improvement as substantial, minimal to moderate, or none. Complications of fat injections were noted. A total of 43 breasts in 37 patients were injected with autologous fat during 47 discrete events; some patients had the procedure repeated and some were treated bilaterally. Of the 43 treated breasts, 25 (58 percent) were reconstructed with implants, 17 (40 percent) were reconstructed with a TRAM (transverse rectus abdominis muscle) flap, and one (2 percent) was reconstructed with a TRAM and an implant.

RESULTS

There were four complications (8.5 percent) in 47 treated breasts: one breast with cellulitis that resolved with antibiotics and three breasts with small, superficial lumps--two of which were biopsied and found to be liponecrotic cysts. Patient follow-up averaged 49 weeks, ranging from 3 weeks to 6 years. There was a substantial contour improvement in ten breasts (21 percent), minimal to moderate improvement in 30 breasts (64 percent), and no improvement in 7 breasts (15 percent).

CONCLUSIONS

Although fat injection in and around the reconstructed breast has limitations, such as fat necrosis and need for repeated injections, our experience indicates that overall it is a very safe technique that can improve or correct significant contour deformities that otherwise would require more complicated, riskier procedures to improve.

Implantation of preadipocyte-loaded hyaluronic acid-based scaffolds into nude mice to evaluate potential for soft tissue engineering

The reconstruction of soft tissue defects following extensive deep burns or tumor resections remains an unresolved problem in plastic and reconstructive surgery since adequate implant materials are still not available. Preadipocytes, immature precursor cells found between mature adipocytes in adipose tissue, are a potential material for soft tissue engineering since they can proliferate and differentiate into adipose tissue after transplantation. In previous studies, we identified hyaluronan benzyl ester (HYAFF 11) sponges to be promising carrier matrices. This study now evaluates, in vitro and in vivo, a new sponge architecture with pores of 400 microm either made of plain HYAFF 11 or HYAFF 11 coated with the extracellular matrix glycosaminoglycan hyaluronic acid. Human preadipocytes were isolated, seeded onto carriers and implanted into nude athymic mice. Explants harvested after 3, 8, and 12 weeks were examined for macroscopical appearance, thickness, weight, pore structure, histology, and immunohistochemistry. Compared to previous studies, we found better penetration of cells into both types of scaffolds, with more extensive formation of new vessels throughout the construct but with only minor adipose tissue. Our encouraging results contribute towards a better seeded and vascularised scaffold but also show that the enhancement of adipogenic conversion of preadipocytes remains a major task for further in vivo experiments.

The Role of Recipient Sites in Fat-Graft Survival

The survival of fat grafts depends on many factors, 1 of the major being early revascularization. Early studies showed that adipose tissue has a low tolerance to ischemia. Some methods have been described to increase the tolerance of adipose tissue to ischemia. This study was designed to compare volume maintenance of the transplanted fat graft in different recipient sites of the rabbit face. Three groups of 5 New Zealand white rabbits were studied. Fat grafts harvested from the right inguinal fat pad were transplanted to the buccomandibular area of the rabbit's face. Three different recipient sites (subcutaneous, supramuscular, and submuscular) were dissected on each side of the face, and groups were formulated based on this difference of recipient sites. Morphometric, as well as histopathologic, analyses were done, and the results revealed a statistically significant increase of fat graft survival in supramuscular layer (81.95% +/- 4.40%) than in subcutaneous (41.62% +/- 3.29%) and submuscular layer (37.31% +/- 5.77%) (P<0.05). This study demonstrates that selection of an "appropriate recipient site" should enhance ultimate fat-graft survival.

A new simple method used to prepare fat for injection

Various clinical and experimental studies on harvesting techniques, donor sites, preparation, and preservation of fat for injection imply that there is no universal agreement on an ideal methodology. Unpredictable and irregular resorption of fat leads to uncertainty about volume maintenance of the transplanted fat necessitating repeat procedures. In this report, the authors present their 5-year clinical experience with facial fat grafting by isolated and combined procedures using a simple method that they developed for fat preparation. This technique includes fat harvesting with syringe aspiration and filtration of the fat aspirate instead of centrifugation. The idea for filtration was inspired by a yogurt concentration method used in Anatolia. The authors also aimed to increase fat survival by using multiple fat injections of minimal amounts into different levels.

Breast tissue engineering

Tissue engineering has the potential to redefine rehabilitation for the breast cancer patient by providing a translatable strategy that restores the postmastectomy breast mound while concomitantly obviating limitations realized with contemporary reconstructive surgery procedures. The engineering design goal is to provide a sufficient volume of viable fat tissue based on a patient's own cells such that deficits in breast volume can be abrogated. To be sure, adipose tissue engineering is in its infancy, but tremendous strides have been made. Numerous studies attest to the feasibility of adipose tissue engineering. The field is now poised to challenge barriers to clinical translation that are germane to most tissue engineering applications, namely scale-up, large animal model development, and vascularization. The innovative and rapid progress of adipose engineering to date, as well as opportunities for its future growth, is presented.

Facteurs influençant la survie de la greffe d’adipocytes

Most authors supported the theory of adipocyte survival. The viability of these cells has been demonstrated by various experimental clinical, radiological and biochemical studies. After a review of the literature, the authors report the various factors, which influence the survival of the transplanted adipocytes. These factors are presented according to their chronology in the operative procedure. The techniques used are very diverse. The reference technique chosen is that described by Coleman (Lipostructure). The following factors are studied: type of anaesthesia, infiltration, donor site of adipose tissue, method of harvesting, method of refining adipose tissue, anabolic complements, receiving site, reinjection technique, number of grafting sessions, freezing of adipose tissue and complementary postoperative treatments. It seems imperative that each phase of the operative procedure should be carried out without damage to the adipocytes, in particular their harvesting, refining and reinjection. All the other factors studied require comparative analysis in order to demonstrate their true importance. This opens up various directions of research aiming to improve the survival of the transplanted adipocytes.

The fate of intramuscularly injected fat autografts: an experimental study in rabbits

An experimental study was designed to assess the viability and revascularization of intramuscularly injected fat autografts. For the study, 18 rabbits were divided into two groups. In the first group, fat was injected intramuscularly (12 rabbits). Autologous fat was obtained from the inguinal area and subsequently injected into the thigh muscle. In the second group, physiologic saline was injected intramuscularly to determine the effects of cannulation and pressure on muscle tissue (6 rabbits). Fat autografts were performed on the right side of the animal, and the left side was used as the control. Scintigraphic imaging and histopathologic examination of the limbs were performed after injection of adipose tissue on days 15, 30, 45, 60, 90, and 120. On the technetium-99m ((99m)Tc) hexamethylpropylene amine oxime scintigraphy, whereas similar activity distribution was observed between the left and right thigh on days 15, 30, and 45, there was increased uptake at the right thigh on days 60, 90, and 120. This increased uptake indicates that there is viable fat tissue in this region. Histopathologic evaluation showed that microcysts resulting from degeneration of some adipocytes and inflammatory changes on day 15 additionally increased vascularity and fibrosis in some animals on day 30, as well as fibrosis, microcysties, and focal calcification areas in adipose tissue on day 45 and later. It was observed that adipose tissue survived in more than 50% of the graft area in all the animals. These findings show that fat autografts can survive in muscle tissue with less than 50% fibrotic change.