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Dermis–fat composite tissues have been widely used in plastic and reconstructive surgery and were previously constructed using hydrogel‐type scaffolds. The constructs can be used for in vitro cosmetic and pharmaceutical testing but are not mechanically strong enough for in vivo applications. In this study, we used heterogeneous (porcine) acellular dermal matrix (PADM) as dermal layer scaffold. PADM was pretreated with the laser micropore technique and then precultured with rat adipose‐derived stem cells (rADSCs) in vitro. rADSCs proliferated well on pretreated/unpretreated PADM, showing increased expression of genes associated with inflammatory regulation, proangiogenesis, and stemness, indicating that pretreated/unpretreated PADM both provide a beneficial microenvironment for rADSCs to exert their paracrine function. After in vitro processing, the rADSCs–polyporous PADM and PADM without pretreatments were implanted into the back of rats respectively, followed by adipose tissue transplantation. After implantation, the inflammation induced by pretreated PADM was significantly attenuated and localized compared to the unpretreated group. Moreover, the vascularization was faster, and more adipose tissue was formed in the pretreated group. Sound dermis–fat composite tissue was constructed with sufficient strength, which can potentially be used for actual repair application.

Human adipose-derived stem cells (hADSCs) and human umbilical vein endothelial cells (HUVECs) co-cultured in vitro are widely used in adipose tissue engineering but exhibit various limitations. Chemokine (C-C motif) ligand 2 (CCL2) has been proved essential during adipogenesis and angiogenesis in vivo. We examined whether adipogenesis and angiogenesis could also be directly promoted by CCL2 in vitro. Cells were cultured with 0, 10, 50, and 100 ng/ml CCL2. The effects of CCL2 on adipogenesis of hADSCs, and lipid accumulation in the positive control group (hADSCs), blank control group (hADSCs + HUVECs), and experimental group (hADSCs + HUVECs + CCL2) in the hADSC and HUVEC direct co-culture system were evaluated by Oil Red O staining. Angiogenesis in the presence of CCL2 was evaluated by Matrigel tube formation assay. Angiogenic-and adipogenic-associated gene and protein expression in the co-culture system were measured by Quantitative Real-time Polymerase Chain Reaction and western blotting, respectively. All concentrations of CCL2 promoted hADSC adipogenic differentiation and HUVEC tube formation (P < 0.05). Following direct co-culture, the experimental group accumulated more lipid droplets than the positive control (P < 0.0001), whereas the latter showed better adipogenesis than the blank control group. 50 ng/ml CCL2 exhibited stronger adipogenic and angiogenic potential than other concentrations.After 72 h of direct co-culture, the mRNA expression of adipogenic differentiation (peroxisome proliferators-activated receptorsγ, CCAAT/enhancer binding proteinα, Leptin, and lipoprotein lipase) and angiogenic genes (vascular endothelial growth factor-A, vascular endothelial growth factor receptor 2, matrix metalloprotein (MMP) 9, and 14) in the experimental group was much higher than in the control (P < 0.05). The addition of 50 ng/ml CCL2 in the system resulted in elevated phosphorylated Protein kinase B/AKT expression. In summary, CCL2 directly promoted adipogenesis of hADSCs and angiogenesis of HUVECs under both monoculture and co-culture condition in vitro possibly by enhancing AKT Zhu Zhu and Linxiumei Guo contribute equally to this manuscript.

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