Characterisation of angiogenetic growth factor production in adipose tissue-derived mesenchymal cells.

Optimal vascularisation of the graft site is significant for improving the outcome of fat grafting. Adipose tissue, specifically the stromal vascular fraction (SVF), is known to regulate its own vascular network. In order to assess the production of angiogenetic growth factors, this study investigated the content of insulin growth factor (IGF), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), leptin, and metallothioneine-9 (MMP-9) in the SVF after incubation in differentiation or proliferation media. The SVF was isolated from human subcutaneous adipose tissue. Cells were either cultured in proliferation medium (PM) or in differentiation medium (DM). The samples were analysed for the respective factors using ELISA after 3 and 6 days. The GF levels showed a distinctive characteristic over time depending on the culture medium. IGF, PDGF, and MMP-9 levels decreased with PM and increased with DM. VEGF levels were increased in both media. Leptin showed a decrease in both media. The differentiation medium was associated with high inter-individual distribution in growth factor production except for PDGF and Leptin. In conclusion, incubation with differentiation medium produces a more reliable increase of selected growth factors than incubation with proliferation medium. Enrichment of fat grafts with growth factor-activated autologous SVF samples could help to enable better ingrowth of the transplanted tissue and a more stable outcome. The scattering of the results could explain the inter-individual differences regarding the outcome.

Moving forwards: the anterior supraclavicular artery perforator (a-SAP) flap: a new pedicled or free perforator flap based on the anterior supraclavicular vessels.

Since the original publication in 1997 the supraclavicular island flap (SIF) has evolved and is now a safe and reliable procedure for head and neck reconstruction. The purpose of this communication is to give an overview of the current indications and outcomes. An analysis of the literature shows documented use in over 400 patients. Flap size is around 10 × 30 cm; in the case of pre-expansion the width can be up to 15 cm. In larger case series the major complication rate is <5%. We have transferred 127 flaps in 79 patients. To unify the widely varying nomenclature and in the light of the new classifications regarding perforator flaps, we propose to rename the flap as the supraclavicular artery perforator (SAP) flap. Furthermore we report our improvements to the original technique that have led to the development a new flap for head and neck reconstruction. We have started to use an anterior supraclavicular pedicle, originating separately from the transverse colli artery. This places the skin island into the deltoideo-pectoral fossa; thus the flap is even more thin and has better colour match to the face. The reliability of this vessel was demonstrated clinically. We have also used the flap as a free flap for hand and foot reconstruction in two patients. Both flaps survived without complications. Shifting the skin island forwards to the thin deltoideo-pectoral tissue and the possibility of transferring it as a free flap expands the possibilities considerably. We propose to name the flap as the anterior supraclavicular artery perforator (a-SAP) flap to distinguish it from other flaps harvested in this area.

The effect of centrifugal forces on viability of adipocytes in centrifuged lipoaspirates.

Standard protocols for autologous fat transfer involve centrifugation of the lipoaspirate for better separation. The effect of the centrifugal forces on cell viability and possible induction of apoptosis is discussed controversially in current literature. We have examined the vitality of adipocytes in lipoaspirates after centrifugation by 8 different accelerations up to 20.000g immediately after the respective centrifugation as well as 4 days later by staining. No significant alterations in the viability of differently centrifuged adipocytes were found. Cultivation of the samples after centrifugation revealed no apoptotic changes. Our results show that centrifugation, as a part of the protocol of lipofilling, has no effect on the survival rate of isolated adipocytes in the purified fat. In contrast, lipoaspirates centrifuged with higher accelerations seem to be better cleansed of oil and cell debris than samples treated with lower centrifugal forces.

A 5-year assessment of safety and aesthetic results after facial soft-tissue augmentation with polyacrylamide hydrogel (Aquamid): a prospective multicenter study of 251 patients.

BACKGROUND: The permanent filler polyacrylamide hydrogel (Aquamid) has been used for soft-tissue augmentation for more than 16 years. To evaluate the safety and efficacy of the material, the manufacturer initiated in 2001 a prospective clinical trial with a follow-up of 5 years. This represents one of the longest running studies on currently used fillers. METHODS: Two hundred fifty-one patients were enrolled in a noncomparative, prospective study and followed at 15 sites in Europe. The follow-up rates were 228 (90.8 percent), 101 (40.2 percent), 81 (32.3 percent), and 116 (46.2 percent) for the 12-, 24-, 36/48-, and 60-month follow-up periods. Patients received an average of 4.3 ml of Aquamid during an average of 2.4 injection sessions. Preferred areas were the nasolabial folds (37 percent) and the lips (28 percent). Study parameters were cosmetic outcome, blood analysis, and recording of local or generalized symptoms, including adverse reactions. RESULTS: Aesthetic outcome was rated as "very good" or "good" by 96.5 percent of patients and by 96.0 percent of investigators at final available follow-up. During the entire study period, a total of 53 adverse events and two serious adverse events were classified as treatment related. Thirteen adverse events were gel indurations and four cases of infection were seen. All had been resolved within the study period. CONCLUSIONS: The study showed a very good aesthetic outcome and few adverse events after injection of polyacrylamide gel for soft-tissue augmentation. Correct application was essential to ensure a favorable result. For patients who desire facial soft-tissue augmentation, Aquamid is an excellent alternative to surgery.

Rectourethral fistula following LDR brachytherapy.

Modern LDR brachytherapy has drastically reduced rectal toxicity and decreased the occurrence of rectourethral fistulas to <0.5% of patients. Therefore, symptoms of late-onset sequelae are often ignored initially. These fistulas cause severe patient morbidity and require interdisciplinary treatment. We report on the occurrence and management of a rectourethral fistula which occurred 4 years after (125)I seed implantation.

Content of the growth factors bFGF, IGF-1, VEGF, and PDGF-BB in freshly harvested lipoaspirate after centrifugation and incubation.

BACKGROUND: In autologous fat transfer, several questions regarding basic biochemical properties of the transplant remain unanswered. Basic fibroblast growth factor (bFGF), insulin-like growth factor (IGF), vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF)-BB have been shown to improve transplantation results. However, no study regarding naturally occurring levels of growth factors in transplanted adipose tissue has yet been performed. In addition, there are no data as to whether intraoperative refinement eliminates or concentrates growth factors. METHODS: The authors investigated the content of bFGF, IGF, VEGF, and PDGF-BB in freshly aspirated adipose tissue and the presence of those factors in the various fractions after centrifugation by means of enzyme-linked immunosorbent assay readings. They also analyzed growth factor content after storage periods of 3 and 5 days and investigated the vitality of freshly centrifuged adipose tissue by staining with Hoechst 33342 and propidium iodide. RESULTS: The authors found significant quantities of bFGF, IGF-1, VEGF, and PDGF-BB (39.9, 113.8, 3.0, and 5.8 pg/mg, respectively) in the lipoaspirate harvested for transplantation. Separation by centrifugation and discarding of the infranatant and supernatant fluid means that most of the growth factors are left in the transplant. The growth factor content in the other fractions was significantly lower. Lipoaspirate can be cultured for several days, with the tissue remaining biologically active and producing significant growth factor levels. CONCLUSION: Knowledge of the naturally occurring range for these growth factor quantities will enable researchers and clinicians to make autologous fat transfer procedures more reliable and safe.

Cryopreservation of mature human adipocytes: in vitro measurement of viability.

Cryopreservation of fat grafts for autologous fat transplantation renders repeated harvesting procedures unnecessary. Anecdotic reports have been published, yet data about adipocyte survival are sparse. The beneficial effect of added cryoprotective agents (CPA) is known from other tissues but has not been investigated in adipocytes. Fat cells were harvested using the Coleman method (n = 24). Tests were done after 0, 2, 7, 14, and 30 days of cooling to -20 degrees C and -80 degrees C and after addition of various CPA. Analysis included cell stains, measurement of metabolic activity by MTT and XTT tests, and measurement of cell stability by assessment of extracellular glycerol-3-phosphate-dehydrogenase enzyme. After freezing, up to 92.7% of metabolic activity was lost, but the addition of CPA led to preservation of up to 54% of baseline activity. Also, lower storage temperature showed more cell destruction but yielded higher viability of the surviving cells. Our results implicate that the widely used practice of simple storage in a freezer leads to reinjection of nonviable tissue. Cell survival can be improved by addition of CPA.

Adaptive soft tissue deformation for a virtual reality surgical trainer.

Real time tissue deformation is an important aspect of interactive virtual reality (VR) environments such as medical trainers. Most approaches in deformable modelling use a fixed space discretization. A surgical trainer requires high plausibility of the deformations especially in the area close to the instrument. As the area of intervention is not known a priori, adaptive techniques have to be applied. We present an approach for real time deformation of soft tissue based on a regular FEM mesh of cube elements as opposed to a mesh of tetrahedral elements used by the majority of soft tissue simulators. A regular mesh structure simplifies the local refinement operation as the elements topology and stiffness are known implicitly. We propose an octree-based adaptive multiresolution extension of our basic approach. The volumetric representation of the deformed object is created automatically from medical images or by voxelization of a surface model. The resolution of the volumetric representation is independent of the surface geometry resolution. The surface is deformed according to the simulation performed on the underlying volumetric mesh.