"Fasting: An Effective Preconditioning Method to Increase Fat Graft Survival"

Preconditioning Strategies for Improving the Outcome of Fat Grafting

Autologous fat grafting is a common procedure in plastic, reconstructive, and aesthetic surgery. However, it is frequently associated with an unpredictable resorption rate of the graft depending on the engraftment kinetics. This, in turn, is determined by the interaction of the grafted adipose tissue with the tissue at the recipient site. Accordingly, preconditioning strategies have been developed following the principle of exposing these tissues in the pretransplantation phase to stimuli inducing endogenous protective and regenerative cellular adaptations, such as the upregulation of stress-response genes or the release of cytokines and growth factors. As summarized in the present review, these stimuli include hypoxia, dietary restriction, local mechanical stress, heat, and exposure to fractional carbon dioxide laser. Preclinical studies show that they promote cell viability, adipogenesis, and angiogenesis, while reducing inflammation, fibrosis, and cyst formation, resulting in a higher survival rate and quality of fat grafts in different experimental settings. Hence, preconditioning represents a promising approach to improve the outcome of fat grafting in future clinical practice. For this purpose, it is necessary to establish standardized preconditioning protocols for specific clinical applications that are efficient, safe, and easy to implement into routine procedures.

Mechanical Stress Improves Fat Graft Survival by Promoting Adipose-Derived Stem Cells Proliferation

Cell-assisted lipotransfer (CAL), defined as co-transplantation of aspirated fat with enrichment of adipose-derived stem cells (ASCs), is a novel technique for cosmetic and reconstructive surgery to overcome the low survival rate of traditional fat grafting. However, clinically approved techniques for increasing the potency of ASCs in CAL have not been developed yet. As a more clinically applicable method, we used mechanical stress to reinforce the potency of ASCs. Mechanical stress was applied to the inguinal fat pad by needling. Morphological and cellular changes in adipose tissues were examined by flow cytometric analysis 1, 3, 5, and 7 days after the procedure. The proliferation and adipogenesis potencies of ASCs were evaluated. CAL with ASCs treated with mechanical stress or sham control were performed, and engraftment was determined at 4 weeks post-operation. Flow cytometry analysis revealed that mechanical stress significantly increased the number as well as the frequency of ASC proliferation in fat. Proliferation assays and adipocyte-specific marker gene analysis revealed that mechanical stress promoted proliferation potential but did not affect the differentiation capacity of ASCs. Moreover, CAL with cells derived from mechanical stress-treated fat increased the engraftment. Our results indicate that mechanical stress may be a simple method for improving the efficacy of CAL by enhancing the proliferation potency of ASCs.

A Surgeon's Empirical Perspectives on Use of High-resolution Ultrasound in Preoperatively Detecting a Rupture in the Context of Breast Implant Crisis in Korea

BACKGROUND

We previously proposed a novel method for detecting a rupture of a breast implant using high-resolution ultrasound (HRUS). We therefore conducted this retrospective, observational study to describe its feasibility in making a preoperative diagnosis of rupture of the device in patients receiving an implant-based augmentation mammaplasty.

METHODS

We initially evaluated the medical records of the patients who had received primary or secondary augmentation mammaplasty using a breast implant at other hospitals for aesthetic or reconstructive purposes between August 31, 2017, and August 31, 2020. The patients underwent breast US using the Aplio i600 (Canon Medical System, Otawara, Tochigi, Japan) system with a 7-18 MHz linear transducer. Through a retrospective review of the patients' medical records, we analyzed their baseline and clinical characteristics. Then, we compared an agreement between preoperative diagnosis of rupture on HRUS and findings at reoperation.

RESULTS

A total of 29 patients with rupture (55 breasts) were evaluated for the performance of ultrasound in making a diagnosis of rupture. This showed that they were unaware of rupture but they were diagnosed with it on ultrasound. Preoperatively, there were no cases of rupture in 110 left breasts (80.9%) and 107 right breasts (78.7%), which exactly matched to the number of breasts without rupture on HRUS. Moreover, preoperatively, there were 26 (19.1%) and 29 cases (21.3%) of rupture in the left and right breast, respectively, which exactly matched to the number of breasts with rupture on HRUS.

CONCLUSIONS

In conclusion, patients who are suspected of having rupture of a breast implant should be stringently evaluated for presence of rupture and, if any, its scope using HRUS. Moreover, we propose that surgeons consider using HRUS in making a preoperative diagnosis of rupture of a breast implant.

LEVEL OF EVIDENCE III

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