With great interest we read the article by Qi et al entitled Effectiveness of a New Enzyme-Free Method for the Preparation of a Decellularized Adipose-Derived Matrix.1 In this study, the authors have proposed an enzymatic-free decellularization method for the preparation of decellularized adipose-derived matrix (DAM). Through both in vitro and in vivo experiments, they demonstrated the sound tissue compatibility and strong adipogenic potential of the DAM.

The enzymatic-free approach employed by the authors involves a series of steps including freeze-thaw cycles, mechanical emulsification, gradient sodium chloride treatment, Triton X-100 treatment, and isopropyl alcohol treatment. A noteworthy aspect of this method is the exclusion of exogenous enzymes, which are conventionally utilized in the preparation of DAM.2 Although this enzyme-free approach avoids the risk of inducing alloantigens and pathogens, concerns remain regarding the potential residual immunogenic nucleic acids. The authors, however, have provided data indicating the successful removal of these immunogenic nucleic acids with their enzymatic-free method. It is crucial for the authors to elaborate on how their enzymatic-free approach effectively removes these immunogenic nucleic acids without the introduction of enzymes.

Another significant aspect to consider is the clinical relevance of this enzymatic-free preparation method. The exclusion of exogenous enzymes makes this approach more amenable to clinical applications. Ideally, an enzymatic-free method would entirely rely on physical means, without the introduction of any exogenous substances, including Triton X-100, for the preparation of DAM. Future studies are needed to develop more effective physical preparation methods. The current enzymatic-free method still incorporates other exogenous components, such as Triton X-100 and isopropyl alcohol. As highlighted by the authors, the use of Triton X-100 aims to eliminate inflammatory cell debris, residual DNA, and the α-gal epitope. However, in practical applications, complete removal of residual Triton X-100 can be challenging. The presence of these residuals can interfere with cell recruitment and adipogenesis, leading to foreign body reactions and reduced volume retention, especially in allogeneic applications.

The authors have provided a relatively standardized protocol for the preparation of decellularized products, which is crucial for obtaining consistent results. Apart from the preparation protocol, the raw materials in the process also play a crucial role in determining the predictability of outcomes. For instance, the cellular and extracellular matrix composition of adipose tissue obtained from patients with different body mass indices (BMIs) can vary, potentially leading to variations in the cost and clinical outcomes of the prepared DAM.

Encouragingly, the decellularized matrix materials prepared by the authors induced fat regeneration upon injection into the subcutaneous layers of nude mice. Although the authors did not delineate the mechanism of adipogenic differentiation, the images provided in Figure 8 demonstrated adipocyte regeneration in both the experimental (enzyme-free decellularized matrix preparation) and control groups (decellularized matrix prepared with the Flynn method). Our inquiry to the authors is whether adipose stem cells were mixed during the injection of the decellularized matrix. If not, this would present an excellent approach for inducing fat regeneration and utilizing it as a premium filling material. However, further investigation is needed to determine the source of such a multitude of perilipin-immunostained positive adipocytes and specifically the identity of the small brown-stained cells in Figure 8, A and B (clearly distinct from mature adipocytes).

In conclusion, although the enzymatic-free method proposed by the authors holds promise for the preparation of DAM with good tissue compatibility and adipogenic potential, further research is needed to address challenges related to the complete removal of immunogenic nucleic acids and residual exogenous substances. Additionally, the impact of variations in raw materials on the consistency and predictability of outcomes should be further investigated.

Disclosures

The authors declared no potential conflicts of interest with respect to the research, authorship, and publication of this article.

Funding

The authors received no financial support for the research, authorship, and publication of this article.

REFERENCES 1

Qi

 

J

,

Li

 

Z

,

Li

 

S

,

Fu

 

S

,

Luan

 

J

.

Effectiveness of a new enzyme-free method for the preparation of a decellularized adipose-derived matrix

.

Aesthet Surg J

.

2023

;

44

(

2

):

NP184

–

NP192

. doi: 2

Flynn

 

LE

.

The use of decellularized adipose tissue to provide an inductive microenvironment for the adipogenic differentiation of human adipose-derived stem cells

.

Biomaterials

.

2010

;

31

(

17

):

4715

–

4724

. doi: Author notes

© The Author(s) 2024. Published by Oxford University Press on behalf of The Aesthetic Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.