Attenuated angiogenesis and macrophage infiltration during adipose tissue regeneration in a megavolume human fat grafting nude mouse model.

BACKGROUND: Survival and regeneration mechanisms of large (>250 mL) fat grafts remain incompletely understood. In fat grafts from volunteers with megavolume fat transfer breast augmentation, neovascularization and inflammatory cell infiltration decreased within 7 days according to histological analysis. We further investigated this phenomenon using a nude mouse model. METHODS: To simulate clinical contexts, chambers containing 1 mL human fat were implanted into nude mice. Chambers allowed selective transfer of tissue fluid from recipient nude mice into chambers, but not capillaries or macrophages. Seven days later, fat was removed from the chamber and reimplanted into a new nude mouse in the open-chambered fat group (OCFG, n=45). Adipose samples from volunteers and explanted grafts from OCFG were subjected to histological analyses. Graft weight, vascularization, and immune response were also compared between the OCFG and conventional direct fat grafting (control group (CG)). RESULTS: Percent tissue integrity, percent fibrosis, adipocyte viability, and neovascularization did not significantly differ between volunteer samples and OCFG grafts at day 7. On day 90, OCFG retention rate was decreased relative to CG and the fibrosis area was larger in the OCFG than in the CG. However, the macrophage and capillary counts were lower in the OCFG group relative to CG at days 7 and 14 after transplantation. CONCLUSIONS: The present study provides histological analyses of megavolume fat grafts sampled from clinical breast augmentation tissues and a xenograft nude mouse model. However, these preliminary results in a small clinical cohort should be further assessed in large allogeneic animal models.

Insights into metabolic characteristics and biological activity changes in Zangju (Citrus reticulata cv. Manau Gan) peel at different maturity stages through UPLC-MS/MS-based metabolomics.

In this study, comprehensive and systematic nontargeted metabolomics analysis was performed with the metabolites of Zangju peel (Citrus reticulata cv. Manau Gan, CRZP, which has been cultivated for over 400 years in Derong County, China.) at four different mature stages. A total of 1878 metabolites were identified, among which flavonoids were the most abundant (62.04 %), and identified 62 key differential metabolites significantly affected by maturity. Based on biological activity measurements, CRZP showed better antioxidant activity, lipase inhibition ability, inhibition of adipogenic differentiation in 3TT-L1 cells and promotion of lipid metabolism, with the biological activity of CRZP at different maturity stages being associated with key differential metabolite. Thus, CRZP is natural antioxidants and possess anti-obesity potential, and industrial production needs to consider the Maturity stage of its collection.

Electronic Nose and Head Space GC-IMS Provide Insights into the Dynamic Changes and Regularity of Volatile Compounds in Zangju (Citrus reticulata cv. Manau Gan) Peel at Different Maturation Stages.

Zangju (Citrus reticulata cv. Manau Gan) is the main citrus cultivar in Derong County, China, with unique aroma and flavour characteristics, but the use of Zangju peel (CRZP) is limited due to a lack of research on its peel. In this study, electronic nose, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), and partial least squares-discriminant analysis (PLS-DA) methods were used to rapidly and comprehensively evaluate the volatile compounds of dried CRZP and to analyse the role of dynamic changes at different maturation stages. The results showed that seventy-eight volatile compounds, mainly aldehydes (25.27%) and monoterpenes (55.88%), were found in the samples at four maturity stages. The contents of alcohols and aldehydes that produce unripe fruit aromas are relatively high in the immature stage (October to November), while the contents of monoterpenoids, ketones and esters in ripe fruit aromas are relatively high in the full ripening stage (January to February). The PLS-DA model results showed that the samples collected at different maturity stages could be effectively discriminated. The VIP method identified 12 key volatile compounds that could be used as flavour markers for CRZP samples collected at different maturity stages. Specifically, the relative volatile organic compounds (VOCs) content of CRZP harvested in October is the highest. This study provides a basis for a comprehensive understanding of the flavour characteristics of CRZP in the ripening process, the application of CRZP as a byproduct in industrial production (food, cosmetics, flavour and fragrance), and a reference for similar research on other C. reticulata varieties.

Fascia Promotes Adipose Tissue Regeneration by Improving Early Macrophage Infiltration after Fat Grafting in a Mouse Model.

BACKGROUND: Low early macrophage fat graft infiltration (within a week of surgery) hinders tissue regeneration, suggesting that macrophages play a vital role in early angiogenesis and adipogenesis. However, the source of macrophages during this period is unclear. METHOD: C57BL/6 mice were split into fascial removal (FR) group and control groups (CG). Mice had a piece of back fascia removed in the FR group, which was immediately replaced in the CG, and inguinal fat injected into the transplantation site of both groups. Separately, fascia was harvested from green fluorescent protein-expressing mice and transplanted into C57BL/6 mice for tracing macrophage infiltration after fat grafting. RESULTS: The number of capillaries in the FR group was lower than that in the CG at days 3 ( P < 0.01) and 7 ( P < 0.05). Moreover, the number of small adipocytes in the FR group was lower than in the CG on days 3, 7, and 14 (all P < 0.05), and the relative expression of several adipogenic proteins was significantly lower in the FR group than in the CG on days 14 and 30. The timeline of macrophage infiltration was consistent with angiogenesis and adipogenesis. The number of macrophages in the FR group was significantly lower than in the CG at days 3 and 7 ( P < 0.05), and there were more fascia-derived macrophages than circulation-derived macrophages infiltrated into fat grafts within 7 days. Finally, the graft retention was lower in the FR group than the CG at day 90 ( P < 0.05). CONCLUSION: In the early stage after fat grafting, fascial macrophage infiltration initiates tissue regeneration, thereby improving graft retention by promoting angiogenesis and adipogenesis. CLINICAL RELEVANCE STATEMENT: In the clinic, injecting fat close to the fascia may increase fat retention. Fascia is widespread and self-regenerating, which may be a promising alternative source of local macrophages, with implications for tissue-engineering therapies such as correction of soft-tissue defects and breast reconstruction.

Early Angiogenesis-Dependent CXCL12 Attracts Adipose-Derived Stem Cells to Promote the Repair of Fat Grafting in a Mouse Model.

BACKGROUND: The unpredictable and unstable tissue retention rate of autologous fat grafting remains an obstacle faced by plastic surgeons. The authors' previous study using a fat grafting mouse model with donor sites showed that adipose-derived stem cell (ASC) infiltration in the recipient site was delayed, leading to poor regeneration and lower retention. Thus, the mechanism behind the differential infiltration of ASCs needed to be explored. METHODS: First, the authors locally injected C-X-C chemokine ligand 12 (CXCL12) or C-X-C motif chemokine receptor 4 (CXCR4) inhibitor AMD3100 in the recipient or donor site, respectively (CXCL12 + AMD3100 - , CXCL12 - AMD3100 + , and CXCL12 + AMD3100 + groups). The authors compared the migration of ASCs, adipose regeneration, and long-term retention. Next, the authors explored the role of angiogenesis using a normal/ischemic mice model in which the authors test the expression of CXCL12/CXCR4, migration of ASCs, and adipose regeneration. RESULTS: Blocking CXCL12 in the donor site using AMD3100 (CXCL12 - AMD3100 + and CXCL12+AMD3100+ groups) could accelerate ASC infiltration and promote adipose regeneration and long-term retention ( P < 0.05) compared with the other groups. CXCL12 and its receptor CXCR4 were more highly expressed in normal than in ischemic adipose tissue; consistently, there were more ASCs infiltrating normal than ischemic adipose tissue early after surgery ( P < 0.05). CONCLUSION: Early angiogenesis is essential for CXCL12 in promoting ASC infiltration, improving adipose tissue repair in the recipient site, and potentiating the long-term fat retention rate. CLINICAL RELEVANCE STATEMENT: The authors provide a proof-of-concept way to improve the outcomes of fat grafting by locally injecting AMD3100, also known as plerixafor, to the donor site.

Corrigendum: Contouring and augmentation of the temple using stromal vascular fraction gel grafting.

[This corrects the article DOI: 10.3389/fsurg.2022.893219.].

Contouring and augmentation of the temple using stromal vascular fraction gel grafting.

Background: Hollowing temples are common in aging Asians. Stromal vascular fraction (SVF) gel is a novel, mechanically processed adipose-derived product containing condensed adipose-derived stem cells and native extracellular matrix, allowing improved fat grafting. The present study evaluated the effectiveness of SVF-gel treatment on temple hollowing. Methods: This prospective, single-center study included an SVF-gel grafting group (n = 34) and a Coleman's fat grafting group (n = 29). Temple contour was assessed using preoperative and postoperative photographs. Temple augmentation was quantified using three-dimensional (3D) technology and an MVS-600 3D scanner system. Patient satisfaction was assessed postoperatively. Results: At 12 months follow-up, the minimal forehead width/forehead width ratio and the width of the temporal peak were increased in both groups (p < 0.05).; and the retention rate (41.2% ± 8.4%) of the SVF-gel group was significantly higher than that of Coleman's fat group (32.6% ± 8.8%; p < 0.05). Moreover, patients in the SVF-gel group reported higher satisfaction scores than those in Coleman's fat group. Conclusions: SVF-gel is effective for temple contouring and augmentation., with increased efficacy compared with Coleman's fat.

Alternatively activated macrophages at the recipient site improve fat graft retention by promoting angiogenesis and adipogenesis.

The inflammatory response mediated by macrophages plays a role in tissue repair. Macrophages preferentially infiltrate the donor site and subsequently, infiltrate the recipient site after fat grafting. This study aimed to trace host-derived macrophages and to evaluate the effects of macrophage infiltration at the recipient site during the early stage on long-term fat graft retention. In our novel mouse model, all mice underwent simulated liposuction and were divided into 2 groups. The fat procurement plus grafting (Pro-Grafting) group was engrafted with prepared fat (0.3 ml). The pro-Grafting+M2 group was engrafted with prepared fat (0.3 ml) mixed with 1.0 × 106 GFP+M0 macrophages, and then, 2 ng IL-4 was injected into the grafts on Day 3. In addition, 1.0 × 106 GFP+M0 macrophages were injected into the tail vein for tracing in the Pro-Grafting group. As a result, GFP+macrophages first infiltrated the donor site and subsequently infiltrated the recipient site in the Pro-Grafting group. The long-term retention rate was higher in the Pro-Grafting+M2 group (52% ± 6.5%) than in the Pro-Grafting group (40% ± 3.5%). CD34+ and CD31+ areas were observed earlier, and expression of the adipogenic proteins PPAR-γ, C/EBP and AP2 was higher in the Pro-Grafting+M2 group than in the Pro-Grafting group. The host macrophages preferentially infiltrate the donor site, and then, infiltrate the recipient site after fat grafting. At the early stage, an increase in macrophages at the recipient site may promote vascularization and regeneration, and thereby improve the fat graft retention rate.

UHPLC-MS/MS method for the determination of azithromycin in human plasma of pediatric patients.

The presence of azithromycin in the human plasma of pediatric patients was determined with a UHPLC-MS/MS assay. Sample preparation was done by protein precipitation, and the separation was achieved on a C18 column by the gradient mixture of the mobile phase A (0.1% acetic acid and 3 mM ammonium acetate in water) and the mobile phase B (0.1% acetic acid and 3 mM ammonium acetate in the solution of acetonitrile, methanol, and water, 47.5/47.5/5, V/V/V). The multiple reaction monitoring mode was adopted to monitor the precursor-to-product ion transitions of m/z 749.6 → m/z 591.5 for azithromycin and m/z 753.6 → m/z 595.5 for azithromycin-13 C-d3 (the internal standard) at the positive ionization mode. The calibration curve ranged from 0.5 to 500.0 ng·mL-1 , and the correlation coefficient was greater than 0.99. The intra- and inter-batch precision was less than 13.7%. Accuracy determined at four concentrations ranged from 99.5 to 110.8%. The extraction recoveries were more than 95%, and the matrix effects were 98-100%. The stability under various conditions was acceptable with the accuracy deviation within 9.2%. In conclusion, our method was simple, sensitive, and reliable for quantifying azithromycin in plasma among pediatric patients.

Adipose matrix complex: a high-rigidity collagen-rich adipose-derived material for fat grafting.

Due to the low percentage of collagen, the rigid support capacity of fat grafts remains unsatisfactory for some clinical applications. In this study, we evaluated a strategy in which adipose matrix complex (AMC) was collected via a mechanical process and transplanted for supportive filling of the face. Our AMC samples were collected from adipose tissue by a filter device consisting of a sleeve, three internal sieves, and a filter bag (100 mesh). AMC derived from adipose tissue had fewer cells than Coleman fat, but much higher levels of collagen and stiffness. Retention rates 90 days after transplantation in nude mice were higher for AMC than for Coleman fat (75±7.5% vs. 42±13.5%; P < 0.05). In addition, AMC maintained a higher stiffness (~6 kPa vs. ~2 kPa; P < 0.01) and stably retained a higher level of collagen. Our findings demonstrate that mechanical collection of AMC from adipose tissue is a practical method for improving fat graft retention and rigid support. This strategy has the potential to improve the quality of lipoaspirates for patients requiring rigid supportive filling.

Recent Developments in Extracellular Matrix Remodeling for Fat Grafting.

Remodeling of the extracellular matrix (ECM), which provides structural and biochemical support for surrounding cells, is vital for adipose tissue regeneration after autologous fat grafting. Rapid and high-quality ECM remodeling can improve the retention rate after fat grafting by promoting neovascularization, regulating stem cells differentiation, and suppressing chronic inflammation. The degradation and deposition of ECM are regulated by various factors, including hypoxia, blood supply, inflammation, and stem cells. By contrast, ECM remodeling alters these regulatory factors, resulting in a dynamic relationship between them. Although researchers have attempted to identify the cellular sources of factors associated with tissue regeneration and regulation of the microenvironment, the factors and mechanisms that affect adipose tissue ECM remodeling remain incompletely understood. This review describes the process of adipose ECM remodeling after grafting and summarizes the factors that affect ECM reconstruction. Also, this review provides an overview of the clinical methods to avoid poor ECM remodeling. These findings may provide new ideas for improving the retention of adipose tissue after fat transplantation.

Development and validation of a radiomics signature for clinically significant portal hypertension in cirrhosis (CHESS1701): a prospective multicenter study.

Clinically significant portal hypertension (CSPH) is associated with an incremental risk of esophageal varices and overt clinical decompensations. However, hepatic venous pressure gradient (HVPG) measurement, the gold standard for defining CSPH (HVPG≥10 mm Hg) is invasive and therefore not suitable for routine clinical practice. This study aims to develop and validate a radiomics-based model as a noninvasive method for accurate detection of CSPH in cirrhosis. The prospective multicenter diagnostic trial (CHESS1701, ClinicalTrials.gov identifier: NCT03138915) involved 385 patients with cirrhosis from five liver centers in China between August 2016 and September 2017. Patients who had both HVPG measurement and contrast-enhanced CT within 14 days prior to the catheterization were collected. The noninvasive radiomics model, termed rHVPG for CSPH was developed based on CT images in a training cohort consisted of 222 consecutive patients and the diagnostic performance was prospectively assessed in 163 consecutive patients in four external validation cohorts. rHVPG showed a good performance in detection of CSPH with a C-index of 0·849 (95%CI: 0·786-0·911). Application of rHVPG in four external prospective validation cohorts still gave excellent performance with the C-index of 0·889 (95%CI: 0·752-1·000, 0·800 (95%CI: 0·614-0·986), 0·917 (95%CI: 0·772-1·000), and 0·827 (95%CI: 0·618-1·000), respectively. Intraclass correlation coefficients for inter- and intra-observer agreement were 0·92-0·99 and 0·97-0·99, respectively. A radiomics signature was developed and prospectively validated as an accurate method for noninvasive detection of CSPH in cirrhosis. The tool of rHVPG assessment can facilitate the identification of CSPH rapidly when invasive transjugular procedure is not available.