Tracing the Change and Contribution of Subcutaneous Adipose to Skin Expansion Using a Luciferase-Transgenic Fat Transplantation Model.

BACKGROUND: During skin expansion, subcutaneous adipose tissue undergoes the greatest change. The adipose layer appears to gradually thin or even disappear in long-term expansion. The response and contribution of adipose tissue to skin expansion remain to be elucidated. METHODS: The authors established a novel expansion model by transplanting luciferase-transgenic adipose tissue into the rat dorsum, followed by integrated expansion, to trace the dynamic changes in subcutaneous adipose tissue during expansion and the migration of adipose tissue-derived cells. In vivo luminescent imaging was performed to continuously track the adipose tissue changes. Histologic analysis and immunohistochemical staining evaluated the regeneration and vascularization of the expanded skin. Growth factor expression in expanded skin with or without adipose tissue was determined to evaluate the paracrine effect of adipose tissue. Adipose tissue-derived cells were traced in vitro by anti-luciferase staining, and their fate was determined by costaining for PDGFRα, DLK1, and CD31. RESULTS: In vivo bioimaging showed that cells in adipose tissue were alive during expansion. After expansion, the adipose tissue exhibited fibrotic-like structures, with more DLK1 + preadipocytes. Skin expanded with adipose tissue was significantly thicker than that without adipose tissue, with more blood vessels and cell proliferation. Vascular endothelial growth factor, epidermal growth factor, and basic fibroblast growth factor expression was higher in adipose tissue than in skin, indicating paracrine support from adipose tissue. Luciferase-positive adipose tissue-derived cells were observed in expanded skin, indicating direct participation in skin regeneration. CONCLUSION: Adipose tissue transplantation can effectively promote long-term skin expansion by contributing to vascularization and cell proliferation by means of various mechanisms. CLINICAL RELEVANCE STATEMENT: The authors' findings suggest that it would be better if the expander pocket is dissected over the superficial fascia to preserve a layer of adipose tissue with skin. In addition, their findings support the treatment of fat grafting when expanded skin presents with thinning.

Autologous Concentrated Growth Factor Increases Skin Thickness and Area during Tissue Expansion: A Randomized Clinical Trial.

BACKGROUND: Mechanical stretching of the skin (ie, tissue expansion) could generate additional skin, but it is limited by the intrinsic growth capacity. The authors conducted a study of autologous concentrated growth factor (CGF) to promote skin regeneration by increasing skin thickness and area during tissue expansion. METHODS: A single-center randomized controlled trial was conducted from 2016 to 2019. Participants undergoing skin expansion received either CGF or saline by means of intradermal injection on the expanded skin (0.02 mL/cm 2 ), for a total of three treatments at 4-week intervals. The primary endpoint was the expanded skin thickness at 12 weeks, which was measured by ultrasound. The secondary endpoints included skin thickness at 4 and 8 weeks and surface area, expansion index, and skin texture score of the expanded skin at 12 weeks. Safety assessments, for infection symptoms and nodule formation, were assessed at 24 weeks. RESULTS: In total, 26 patients were enrolled and assigned to the CGF or control group. Compared with the control group, the CGF group had significantly increased skin thickness at 8 (control, 1.1 ± 0.1 mm; CGF, 1.4 ± 0.1 mm; -0.6 to 0.0 mm; P = 0.047) and 12 weeks (control, 1.0 ± 0.1 mm; CGF, 1.3 ± 0.1 mm; -0.6 to 0.0 mm; P = 0.047). Compared with the baseline thickness (control, 1.6 ± 0.1 mm; CGF, 1.5 ± 0.1 mm; -0.3 to 0.5 mm; P = 0.987), skin thickness was sustained in the CGF group at 8 weeks after treatment (-0.1 to 0.3 mm; P = 0.711) but decreased in the control group (0.3 to 0.7 mm; P < 0.001). At 12 weeks, the CGF group showed greater increases in surface area (control, 77.7 ± 18.5 cm 2 ; CGF, 135.0 ± 15.7 cm 2 ; 7.2 cm 2 to 107.4 cm 2 ; P = 0.027) and expansion index (control, 0.9 ± 0.1; CGF, 1.4 ± 0.2; 0.0 to 0.8; P = 0.030) than the control group. In addition, CGF-treated skin showed an improvement in texture [CGF: grade 3, n = 2 (15.8%), grade 2, n = 4 (30.7%); control: grade 3, n = 0 (0.0%), grade 2, n = 3 (23.0%)]. No severe adverse events occurred. CONCLUSION: CGF treatment increases skin thickness and area during tissue expansion, and represents a safe and effective strategy for managing skin expansion. CLINICAL RELEVANCE STATEMENT: The findings of this study indicate that it is practically feasible to improve skin regeneration by applying autologous platelet concentrate therapy for skin expansion management. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

The effect of glycerol as a cryoprotective agent in the cryopreservation of adipose tissue.

BACKGROUND: Long-term preservation of adipose tissue is crucial for clinical applications. Researchers should consider both efficiency and biosafety when choosing a cryoprotective agent (CPA) for adipose tissue preservation. Glycerol has been applied as a nontoxic CPA for multiple tissues but not adipose tissue. We aimed to evaluate the efficacy of glycerol as a CPA for adipose tissue cryopreservation. METHODS: Fresh human adipose tissues were obtained from patients who underwent liposuction and divided into 1 mL samples. Each sample was randomly mixed with 1 mL of CPA: 60-100% glycerol, 0.25 mol/L trehalose or DMSO + FBS and cryopreserved in - 196 °C liquid nitrogen for one month. After thawing and elution, the tissues were immediately evaluated for activity and structural integrity in vitro. Then, 0.2 mL of each sample was transplanted subdermally to the nude mouse dorsum and harvested after one month for histological examination to assess the effect of the cryopreserved fat in transplantation. RESULTS: After cryopreservation, the samples treated with DMSO + FBS, trehalose, 60% and 70% glycerol had a more integrated structure than the samples in other groups. Tissues preserved with 70% glycerol had the highest G3PDH activity of 24.41 ± 0.70, comparable to 24.76 ± 0.48 in fresh tissue (p > 0.05). Adipose-derived stem cells (ASC) viability, proliferation and differentiation capability were also better preserved in 70% glycerol group. In vivo analysis showed that tissue preserved with 70% glycerol had a retention rate of 52.37 ± 7.53%, significantly higher than other groups. Histological observation demonstrated better structural integrity and viability in 70% glycerol group. Compared to the DMSO + FBS and trehalose groups, the glycerol groups showed lower tissue inflammation. CONCLUSION: Glycerol (70%) is efficient in adipose tissue cryopreservation. Glycerol-based CPAs, which are nontoxic and show biosafety, are a promising solution for clinical tissue cryopreservation.

Mechanical Stretching Can Modify the Papillary Dermis Pattern and Papillary Fibroblast Characteristics during Skin Regeneration.

Clinical application of mechanical stretching is a reconstructive method for skin repair. Although studies have reported dermal fibroblast heterogeneity, whether stretching affects individual fibroblast subpopulations equally remains unclear. In this study, we show the changes in dermal structure and papillary fibroblast (Fp) in regenerated human skin. Exhausted skin regeneration caused dermal‒epidermal junction flattening, papillary dermis thinning, and an increase in type III collagen-to-type I collagen ratio, with upregulated hallmarks of aging. Well-regenerated skin displayed a notable increase in the Fp population. Consistent changes were observed in the rat expansion model. Moreover, we found that TGFß1 expression was especially increased in skin showing good regeneration. Activation of the TGFß1/SMAD2/3 pathway improved exhausted skin regeneration and resulted in increased collagen content and Fp proliferation, whereas pharmacological inhibition of TGFß1 action impacted well-regenerated skin. Short-term mechanical stretching that promoted skin regeneration enhanced Fp proliferation, extracellular matrix synthesis, and increased TGFß1 expression, leading to good regeneration. Conversely, long-term stretching induced premature Fp senescence, leading to poor regeneration. This work shows the mechanism of mechanical stretching in well-skin regeneration that enhances Fp proliferation and extracellular matrix synthesis through the TGFß1/SMAD2/3 pathway and highlights a crucial role of Fps in stretching-induced skin regeneration.

Superiority of Adipose-derived CD34 + Cells over Adipose-derived Stem Cells in Promoting Ischemic Tissue Survival.

BACKGROUND: Tissue ischemia usually leads to necrosis and is a threatening condition associated with reconstructive surgery. Promoting the survival of ischemic tissue is critical for improving clinical outcomes. Although various solutions based on stem cells have been reported, there are still limitations to clinical translation. The aim of this study was to develop an effective method to promote the survival of ischemic tissue. METHODS: Adipose-derived CD34 + and CD34- cells were obtained by magnetic bead sorting from the stromal vascular faction (SVF). Adipose-derived stem cells (ADSCs) were collected by subculture. The angiogenic capacities of CD34 + cells, CD34- cells and ADSCs were evaluated in vitro by comparing mRNA and protein expression. Random axial flaps in nude mice were used to evaluate the efficacy of these cells in protecting tissue from necrosis. The effect of these cells in preventing inflammation was also evaluated. RESULTS: Our data suggest that CD34 + cells expressed higher levels of angiogenetic factors and lower levels of inflammatory factors than the other cell types. More vessel branches were formed when human umbilical vein endothelial cells (HUVECs) were treated with conditioned medium from CD34 + cells than conditioned medium from the other cell types. Compared to ADSCs, CD34 + cells showed significantly higher efficacy in promoting tissue survival. More CD31 + cells and higher levels of angiogenic factors were observed in tissues from the CD34 + group than in those from the other groups. Lower levels of the proinflammatory factors TNF-α and IL-1b and higher levels of anti-inflammatory factors were found in the CD34 + group than in the other groups. CONCLUSION: Adipose-derived CD34 + cells showed better efficacy in improving ischemic tissue survival than ADSCs by reducing tissue inflammation and promoting angiogenesis. CD34 + cells can be obtained easily and may be suitable for clinical applications.

Autologous Concentrated Growth Factors Combined with Topical Minoxidil for the Treatment of Male Androgenetic Alopecia: A Randomized Controlled Clinical Trial.

Background: Minoxidil (MXD) is an U.S. Food and Drug Administration-approved drug for the topical treatment of androgenetic alopecia (AGA) with minor side effects, but its hair growth (HG) effect is unsatisfactory. Methods: A double-blinded within-subjects randomized clinical trial was conducted on 16 male AGA patients who showed limited improvement after MXD treatment. Eligible participants received three concentrated growth factor (CGF) injections on half of the scalp and the placebo on the other side at 4-week intervals, and MXD was applied twice daily on both sides throughout the follow-up period. The primary endpoint was the HG ratio at V4. The secondary endpoints included the HG ratios at V2, V3, and V5; hair density and T/V ratio at V2, V3, V4, and V5; Global Aesthetic Improvement Scale (GAIS) scores at V4 and V5; and participant satisfaction at V4. Results: Each group included 16 subjects; each half of the scalp was randomly assigned to the MXD+CGF or MXD group. The HG ratio at V4 was higher in the MXD+CGF group than in the MXD group. The MXD+CGF group had significant improvements in hair density, HG ratio, and T/V ratio compared with the MXD group over the follow-up period. The GAIS scores and participant satisfaction were higher in the MXD+CGF group than in the MXD group. Unexpectedly, the MXD+CGF treatment hastened HG, which was sustained for 3 months after discontinuation. No severe adverse events occurred. Conclusions: The combined treatment of MXD and CGF is safe and more efficient for AGA patients. Combining CGF can expedite the potency of MXD and provide patients with fast and lasting HG.

The combination of trehalose and glycerol: an effective and non-toxic recipe for cryopreservation of human adipose-derived stem cells.

BACKGROUND: Adipose-derived stem cells (ADSCs) promote tissue regeneration and repair. Cryoprotective agents (CPAs) protect cells from cryodamage during cryopreservation. Safe and efficient cryopreservation of ADSCs is critical for cell-based therapy in clinical applications. However, most CPAs are used at toxic concentrations, limiting their clinical application. OBJECTIVE: The aim of this study is to develop a non-toxic xeno-free novel CPA aiming at achieving high-efficiency and low-risk ADSC cryopreservation. METHODS: We explored different concentrations of trehalose (0.3 M, 0.6 M, 1.0 M, and 1.25 M) and glycerol (10%, 20%, and 30% v/v) for optimization and evaluated and compared the outcomes of ADSCs cryopreservation between a combination of trehalose and glycerol and the commonly used CPA DMSO (10%) + FBS (90%). All samples were slowly frozen and stored in liquid nitrogen for 30 days. The effectiveness was evaluated by the viability, proliferation, migration, and multi-potential differentiation of the ADSCs after thawing. RESULTS: Compared with the groups treated with individual reagents, the 1.0 M trehalose (Tre) + 20% glycerol (Gly) group showed significantly higher efficiency in preserving ADSC activities after thawing, with better outcomes in both cell viability and proliferation capacity. Compared with the 10% DMSO + 90% FBS treatment, the ADSCs preserved in 1.0 M Tre + 20% Gly showed similar cell viability, surface markers, and multi-potential differentiation but a significantly higher migration capability. The results indicated that cell function preservation can be improved by 1.0 M Tre + 20% Gly. CONCLUSIONS: The 1.0 M Tre + 20% Gly treatment preserved ADSCs with a higher migration capability than 10% DMSO + 90% FBS and with viability higher than that with trehalose or glycerol alone but similar to that with 10% DMSO + 90% FBS and fresh cells. Moreover, the new CPA achieves stemness and multi-potential differentiation similar to those in fresh cells. Our results demonstrate that 1.0 M Tre + 20% Gly can more efficiently cryopreserve ADSCs and is a non-toxic CPA that may be suitable for clinical applications.

[Eco-fitness of county-level agricultural leading industry structure: assessment and development prediction].

Based on the 'three critical points' theory of eco-fitness, and by using dynamic weighting and fitting methods, an assessment system for the eco-fitness of county-level agricultural leading industry structure was constructed, and, taking Zhangqiu of Shandong Province, East China as a case, the eco-fitness of county-level agricultural leading industry structure was assessed and predicted. Due to the limited agro-ecological resources, the comprehensive eco-fitness index of four kinds of agricultural leading industry in Zhangqiu presented an upward trend from 2005 to 2010, but a downward trend from 2011 to 2015. The eco-fitness indices of oil crops and fruits would be negative in 2015. The applied research in Zhangqiu confirmed the validity of the assessment system constructed for the eco-fitness of county-level agriculture leading industry structure and the rationality of the prediction model.