Sustained Overcorrection After Autologous Facial Fat Grafting in the Pediatric Population: A Case Series

Comparison of Yield, Purity, and Functional Properties of Large-Volume Exosome Isolation Using Ultrafiltration and Polymer-Based Precipitation

BACKGROUND

Mesenchymal stem cell-derived exosomes are known to produce effects similar to those of source cells and therefore represent a new approach in cell-free regenerative medicine. Their potential clinical application demands efficient isolation of stable and functional exosomes from a large volume of biological fluid.

METHODS

Exosomes from adipose-tissue conditioned medium of the same volume were isolated using either (1) ultrafiltration with size exclusion or (2) ExoQuick-TC. The isolated exosomes were characterized by protein concentration, particle size, exosomal marker expression, RNA expression profiles, and roles in dermal fibroblast proliferation and migration.

RESULTS

Both isolation methods produced exosomes within the size range defined for exosomes (50 to 200 nm) and common markers were enriched. Compared to the ExoQuick-TC precipitation method, the ultrafiltration method produced a significantly higher protein yield (p < 0.001) but a lower particle-to-protein ratio (p < 0.05); it also yielded higher RNA contents from the same fat tissue indicated by housekeeping genes, but with overall lower purity. The expression of several mRNAs and miRNAs related to tissue regeneration showed that there was no statistical difference between both methods, except miR-155 and miR-223 (p < 0.05). However, there was no difference in overall fibroblast proliferation and migration between exosomes isolated by these two methods.

CONCLUSIONS

Ultrafiltration with size exclusion demonstrated higher yields, acceptable purity, and comparable biophysical properties and biological functions to the more expensive commercial precipitation method. Therefore, it may conceivably be translated into yield-efficient and cost-effective modalities for therapeutic purposes.

CLINICAL RELEVANCE STATEMENT

Ultrafiltration with size exclusion may be amenable for exosome isolation from large-volume complex fluids such as tissue conditioned media for clinical application in future regenerative medicine.

Senescence of donor cells impairs fat graft regeneration by suppressing adipogenesis and increasing expression of senescence-associated secretory phenotype factors

Background

Fat grafting has been regarded as a promising approach for regenerative therapy. Given the rapidly aging population, better understanding of the effect of age on fat graft outcomes and the underlying mechanisms is urgently needed.

Methods

C57/BL6 mice [old (O, 18–20-month-old) and young (Y, 4-month-old)] were randomized to four fat graft groups [old-to-old (O-O), young-to-young (Y-Y), old-to-young (O-Y), and young-to-old (Y-O)]. Detailed cellular events before and after grafting were investigated by histological staining, RNA sequencing, and real-time polymerase chain reaction. The adipogenic differentiation potential of adipose-derived mesenchymal stem cells (AD-MSCs) from old or young donors was investigated in vitro. Additionally, adipogenesis of AD-MSCs derived from old recipients was evaluated in the culture supernatant of old or young donor fat tissue.

Results

After 12 weeks, the volume of fat grafts did not significantly differ between the O-O and O-Y groups or between the Y-Y and Y-O groups, but was significantly smaller in the O-O group than in the Y-O group and in the O-Y group than in the Y-Y group. Compared with fat tissue from young mice, senescence-associated secretory phenotype (SASP) factors were upregulated in fat tissue from old mice. Compared with the Y-O group, adipogenesis markers were downregulated in the O-O group, while SASP factors including interleukin (IL)-6, tumor necrosis factor-α, and IL-1β were upregulated. In vitro, AD-MSCs from old donors showed impaired adipogenesis compared with AD-MSCs from young donors. Additionally, compared with the culture supernatant of young donor fat tissue, the culture supernatant of old donor fat tissue significantly decreased adipogenesis of AD-MSCs derived from old recipients, which might be attributable to increased levels of SASP factors.

Conclusions

Age has detrimental effects on fat graft outcomes by suppressing adipogenesis of AD-MSCs and upregulating expression of SASP factors, and fat graft outcomes are more dependent on donor age than on recipient age. Thus, rejuvenating fat grafts from old donors or banking younger adipose tissue for later use may be potential approaches to improve fat graft outcomes in older adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02383-w.

Isolated Fat Grafting for Reconstruction of Lower Face Volumetric Asymmetry in Skeletally Immature Patients: A Clinical Outcome Study

BACKGROUND

The purpose of this study was to assess the objective and subjective outcomes of lower face volumetric (contour) asymmetry correction with isolated fat grafting in skeletally immature patients.

METHODS

A prospective analysis was conducted of skeletally immature patients (n = 73) with craniofacial microsomia and Parry-Romberg syndrome who underwent isolated fat grafting (with no previous or concomitant bone surgery) using anatomical surgical principles (facial subunits and fat compartments) for the reconstruction of lower face volumetric asymmetry. Objective ultrasound and photogrammetric lower face symmetry analyses were blindly performed preoperatively and at 3 and 12 months postoperatively. A panel assessment of blinded surgical professionals and laypersons was also obtained to grade the subjective lower face symmetry.

RESULTS

There were significant (all P < 0.05) postoperative objective and subjective lower face symmetry enhancements (preoperative < postoperative) after isolated fat grafting, with no differences (all P > 0.05) between 3 versus 12 months' postoperative comparisons.

CONCLUSIONS

Growing patients with unilateral lower face volumetric asymmetries presented with improvement of objective and subjective symmetry after a single isolated fat grafting procedure.

Applications of Fat Grafting in Pediatric Patients

Autologous fat grafting has become a widely utilized technique for a variety of cosmetic and reconstructive procedures. Its potential for volume restoration and tissue regeneration has made it a popular method for treating soft tissue defects in both adult and pediatric populations. While autologous fat grafting in the pediatric setting is not as well characterized as it is in the adult setting, various reports have demonstrated the safety and utility of its applications in nonadult patient populations. In this article, we present the first comprehensive review of the current applications of autologous fat grafting in pediatric patients. Specific challenges to fat grafting in the pediatric setting and future applications will also be discussed.

Fat Grafting in Managing Craniofacial Deformities

BACKGROUND

The successful correction of craniofacial contour deformities remains a major challenge in plastic surgery. This article reviews important concepts and strategies for craniofacial fat grafting and presents a SOBRAPAR Hospital algorithm focused on achieving craniofacial contour symmetry as early as possible without compromising function.

METHODS

Principle-based methods (i.e., anatomical facial fat compartments, fluid accommodation model, multistage site-specific craniofacial fat grafting, and structural fat-grafting technique) were itemized into an algorithm to aid in planning and selecting the best surgical approach (i.e., bone and/or soft tissue procedures) in order to obtain craniofacial contour symmetry.

RESULTS

The treatment plan and choice of surgical technique implemented to address bone and/or or soft tissue deformities were determined by specific diagnosis, patient age at presentation, and functional status. Bony reconstruction in skeletally immature patients is reserved solely for those patients with functional issues.

CONCLUSION

By adopting principle-based methods and fat compartment theory, we are able to achieve craniofacial contour symmetry and aesthetically pleasing outcomes without compromising function.

Identifying Three-Dimensional Facial Fluctuating Asymmetry in Normal Pediatric Individuals: A Panel Assessment Outcome Study of Clinicians and Observers

This study measured three-dimensional facial fluctuating asymmetry in 600 normal and healthy Taiwanese individuals (6 to 12 years old) and assessed the perceptions of increasing levels of facial fluctuating asymmetric severity by using a panel composed of 20 clinicians (surgical professionals), as well as 20 adult and 40 pre-adolescent observers. On average, this normal cohort presented a facial fluctuating asymmetry of 0.96 ± 0.52 mm, with 0.52 ± 0.05, 0.67 ± 0.09, 1.01 ± 0.10, and 1.71 ± 0.36 mm for levels I, II, III, and IV of severity, respectively. For all categories of raters, significant differences in the average symmetry-asymmetry scale values were observed, with level I < level II < level III = level IV (all p < 0.01, except for level III vs. IV comparisons with p > 0.05). For level I, pre-adolescent observers presented a significantly (p < 0.05) higher symmetry-asymmetry scale value than adult observers, with no significant (all p > 0.05) differences for other comparisons. For overall facial asymmetry and levels II, III, and IV, no significant (all p > 0.05) differences were observed. This study reveals that the normal pediatric face is asymmetric and the panel assessment of facial fluctuating asymmetry was influenced by the level of severity and the category of raters and contributes to the literature by revealing that pre-adolescent raters present a similar or higher perception of facial asymmetry than adult raters.

Fat Grafting into Younger Recipients Improves Volume Retention in an Animal Model

BACKGROUND

Soft-tissue deficits associated with various craniofacial anomalies can be addressed by fat grafting, although outcomes remain unpredictable. Furthermore, consensus does not exist for timing of these procedures. Whereas some advocate approaching soft-tissue reconstruction after the underlying skeletal foundation has been corrected, other studies have suggested that earlier grafting may exploit a younger recipient niche that is more conducive to fat graft survival. As there is a dearth of research investigating effects of recipient age on fat graft volume retention, this study compared the effectiveness of fat grafting in younger versus older animals through a longitudinal, in vivo analysis.

METHODS

Human lipoaspirate from three healthy female donors was grafted subcutaneously over the calvaria of immunocompromised mice. Volume retention over 8 weeks was evaluated using micro-computed tomography at three experimental ages: 3 weeks, 6 months, and 1 year. Histologic examination was performed on explanted grafts to evaluate graft health and vascularity. Recipient-site vascularity was also evaluated by confocal microscopy.

RESULTS

The greatest retention of fat graft volume was noted in the youngest group compared with both older groups (p < 0.05) at 6 and 8 weeks after grafting. Histologic and immunohistochemical analyses revealed that improved retention in younger groups was associated with greater fat graft integrity and more robust vascularization.

CONCLUSION

The authors' study provides evidence that grafting fat into a younger recipient site correlates with improved volume retention over time, suggesting that beginning soft-tissue reconstruction with fat grafting in patients at an earlier age may be preferable to late correction.

Autologous Free Fat Grafting for Management of the Facial Contour Asymmetry

BACKGROUND

The purposes of this study were to report autologous free fat grafting as the workhorse procedure to augment the facial soft-tissue envelope and restore facial contour symmetry of patients with asymmetric facial malformations; to detail the SOBRAPAR Hospital algorithm for soft-tissue reconstruction of patients with facial contour asymmetry; and to assess facial symmetry after fat grafting.

METHODS

A retrospective analysis of consecutive patients (n = 178) who underwent fat grafting to restore the facial contour symmetry according to the SOBRAPAR Hospital algorithm between 2009 and 2016 was conducted. Computerized photogrammetric quantitative and qualitative facial symmetry analyses were performed.

RESULTS

There were significant (all P < 0.05) postoperative quantitative facial symmetry enhancement and an overall qualitative facial symmetry enhancement, with a mean fat graft procedures per patient of 1.6 ± 0.7, ranging of 1 to 3.

CONCLUSION

A significant improvement of facial contour symmetry was obtained in a subset of patients using fat grafting according to the SOBRAPAR Hospital algorithm.