The ideal stem cell for use in functional tissue engineering needs to be abundantly available, harvested with minimal morbidity, differentiated reliably down various pathways and able to be transplanted safely and efficaciously. Adult human adipose tissue contains a population of mesenchymal stem cells, termed ‘adipose‐derived stem cells’ (ASC), which seem to fulfil most, if not all, of these criteria. ASC can be harvested readily, safely, and in relative abundance by modern liposuction techniques. They are capable of differentiating into other mesenchymal tissue types, including adipocytes, chondrocytes, myocytes and osteoblasts. They also show angiogenic properties, with recent evidence of a potential role in healing radiotherapy‐damaged tissue, possibly due to their secretion of vascular endothelial growth factor. Similarly, they may have a role in healing chronic wounds, and as such are being investigated in phase 1 trials for their ability to aid healing of recurrent Crohn’s fistulae. Subsequently they have a wide range of potential clinical uses in all fields of surgery. This article reviews the current and potential clinical applications of ASC in relation to surgery, as well as methods for their isolation, differentiation and molecular characterization.
1 March 2011 in Plastic and Reconstructive Surgery
This study evaluated patients who underwent primary breast surgery within a single group practice from 1994 to 2009. Reoperations were divided by reoperation reason into total reoperations and implant-specific reoperations. The authors hypothesized that the implant-specific reoperation rate will provide the most accurate measurement of complications caused by the breast implant device. A total of 812 patients received the same brand of breast implant for primary breast augmentation or augmentation/mastopexy. Safety and efficacy data were recorded and complication rates were calculated. Statistics were applied using Kaplan-Meier estimated cumulative incidence calculations. This study included 482 patients with saline and 330 patients with silicone implants. The most common complications included capsular contracture, rippling, rupture, infection, and hematoma. A total of 8.2 percent of patients developed Baker grade III/IV capsular contracture by 6 years. The raw incidence of rippling was 7.1 percent, and the rate was significantly increased in underweight patients with subglandular saline implants (p = 0.045). The rate of total reoperation at 1 year was 14.2 percent. While a significantly increased rate of total reoperation was seen for silicone compared with saline implants (p < 0.01), no difference was seen in the rate of implant-specific reoperation for saline compared to silicone implants (p = 0.582). The use of total reoperation rates as an indication of complications of breast implants can lead to both an overestimation of implant-related complications and the inaccurate conclusion that silicone implants result in higher complication rates than saline implants. The implant-specific reoperation rate may provide a more accurate incidence of implant complications than the total reoperation rate, which includes reoperations for factors unrelated to the implant.
After more than a century of use, fat grafting is firmly entrenched in the skill set of plastic surgeons. While macrofat grafting is relatively predictable and reliable, microfat grafting by injection is still in the stages of technical evolution. Review of the current literature suggests that revascularization may take up to 21 days to reach the center of a microfat graft. We recommend harvesting by excision (or gentle aspiration), processing by short and gentle centrifuge to separate the layers, and reinjection of the lower layer via a fine cannula (for example, 17 gauge for the face) and a 1-mL syringe with multiple passes, injecting only a tiny amount with each pass as the needle is withdrawn, to obtain the most reliable clinical outcome.
1 November 2015 in Stem Cells and Cloning: Advances and Applications
Since the discovery of adipose-derived stem cells (ASC) in human adipose tissue nearly 15 years ago, significant advances have been made in progressing this promising cell therapy tool from the laboratory bench to bedside usage. Standardization of nomenclature around the different cell types used is finally being adopted, which facilitates comparison of results between research groups. In vitro studies have assessed the ability of ASC to undergo mesenchymal differentiation as well as differentiation along alternate lineages (transdifferentiation). Recently, focus has shifted to the immune modulatory and paracrine effects of transplanted ASC, with growing interest in the ASC secretome as a source of clinical effect. Bedside use of ASC is advancing alongside basic research. An increasing number of safety-focused Phase I and Phase IIb trials have been published without identifying any significant risks or adverse events in the short term. Phase III trials to assess efficacy are currently underway. In many countries, regulatory frameworks are being developed to monitor their use and assure their safety. As many trials rely on ASC injected at a distant site from the area of clinical need, strategies to improve the homing and efficacy of transplanted cells are also being explored. This review highlights each of these aspects of the bench-to-bedside use of ASC and summarizes their clinical utility across a variety of medical specialties.
Among green tea catechins, epigallocatechin gallate (EGCG) is the most abundant and has the highest biological activities. This study aims to develop and statistically optimise an EGCG-loaded niosomal system to overcome the cutaneous barriers and provide an antioxidant effect. EGCG-niosomes were prepared by thin film hydration method and statistically optimised. The niosomes were characterised for size, zeta potential, morphology and entrapment efficiency. Ex vivo permeation and deposition studies were conducted using full-thickness human skin. Cell viability, lipid peroxidation, antioxidant enzyme activities after UVA-irradiation and cellular uptake were determined. The optimised niosomes were spherical and had a relatively uniform size of 235.4 ± 15.64 nm, with a zeta potential of −45.2 ± 0.03 mV and an EE of 53.05 ± 4.46%. The niosomes effectively prolonged drug release and demonstrated much greater skin penetration and deposition than free EGCG. They also increased cell survival after UVA-irradiation, reduced lipid peroxidation, and increased the antioxidant enzymes’ activities in human dermal fibroblasts (Fbs) compared to free EGCG. Finally, the uptake of niosomes was via energy-dependent endocytosis. The optimised niosomes have the potential to be used as a dermal carrier for antioxidants and other therapeutic compounds in the pharmaceutical and cosmetic industries.