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Stem cells play a key role in tissue regeneration due to their self-renewal and multidirectional differentiation, which are continuously regulated by signals from the extracellular matrix (ECM) microenvironment. Therefore, the unique biological and physical characteristics of the ECM are important determinants of stem cell behavior. Although the acellular ECM of specific tissues and organs (such as the skin, heart, cartilage, and lung) can mimic the natural microenvironment required for stem cell differentiation, the lack of donor sources restricts their development. With the rapid development of adipose tissue engineering, decellularized adipose matrix (DAM) has attracted much attention due to its wide range of sources and good regeneration capacity. Protocols for DAM preparation involve various physical, chemical, and biological methods. Different combinations of these methods may have different impacts on the structure and composition of DAM, which in turn interfere with the growth and differentiation of stem cells. This is a narrative review about DAM. We summarize the methods for decellularizing and sterilizing adipose tissue, and the impact of these methods on the biological and physical properties of DAM. In addition, we also analyze the application of different forms of DAM with or without stem cells in tissue regeneration (such as adipose tissue), repair (such as wounds, cartilage, bone, and nerves), in vitro bionic systems, clinical trials, and other disease research.

Background Vascular embolism is the most severe complication after autologous fat grafting. With a worldwide increase in fat grafting, there has been a rise in severe vascular complications, such as ophthalmic artery embolism, cerebral artery embolism, and even death. This article aims to review the role of fat in causing severe vascular complications and the association between fat grafting and severe vascular complications. Methods A critical review was conducted by appraising the cases of severe vascular complications associated with facial fat grafting reported globally. Repeated cases that were reported in multiple publications were further screened. Results The final search yielded 50 publications in English that met the inclusion criteria for review. A total of 113 cases of fat-induced severe vascular complications in the literature were identified. The number of cases reported yearly has increased over time, with even more significant increases since 2010. The glabella and temple are the most common sites of severe vascular complications described in the literature. In addition, only one case of ophthalmic artery embolism and one case of cerebral artery embolism have been treated successfully. Conclusions Given the increase in reported cases of severe vascular complications, both doctors and patients should pay careful attention to the risks of facial fat grafting. Because of the unclear mechanism of vascular embolism and the lack of guidelines for prevention and treatment, the effective cure rate is unsatisfactory. We propose that preventing vascular embolism is a priority in fat grafting and that timely, multidisciplinary treatment should be performed when severe vascular complications occur. It is necessary in future studies to explore the mechanisms of vascular embolism and effective treatment strategies to promote the development of fat grafting.