Twist2 contributes to skin regeneration and hair follicle formation in mouse fetuses.

Unlike adult mammalian wounds, early embryonic mouse skin wounds completely regenerate and heal without scars. Analysis of the underlying molecular mechanism will provide insights into scarless wound healing. Twist2 is an important regulator of hair follicle formation and biological patterning; however, it is unclear whether it plays a role in skin or skin appendage regeneration. Here, we aimed to elucidate Twist2 expression and its role in fetal wound healing. ICR mouse fetuses were surgically wounded on embryonic day 13 (E13), E15, and E17, and Twist2 expression in tissue samples from these fetuses was evaluated via in situ hybridization, immunohistochemistry, and reverse transcription-quantitative polymerase chain reaction. Twist2 expression was upregulated in the dermis of E13 wound margins but downregulated in E15 and E17 wounds. Twist2 knockdown on E13 left visible marks at the wound site, inhibited regeneration, and resulted in defective follicle formation. Twist2-knockdown dermal fibroblasts lacked the ability to undifferentiate. Furthermore, Twist2 hetero knockout mice (Twist + /-) formed visible scars, even on E13, when all skin structures should regenerate. Thus, Twist2 expression correlated with skin texture formation and hair follicle defects in late mouse embryos. These findings may help develop a therapeutic strategy to reduce scarring and promote hair follicle regeneration.

Esthetic Posterior Reconstruction of Lower Eyelid Using Stripe-Shaped Antihelix Cartilage With Perichondrium.

Eyelid malignancies are often resected in the entire layer, typically requiring anterior and posterior lamellae reconstruction. Posterior lamella reconstruction has been reported using grafts from the nasal septum, palatal mucosa, and auricular cartilage, which have advantages and disadvantages. The authors performed anterior and posterior lamellar reconstruction using a local skin flap and stripe-shaped anti-helical cartilage with the perichondrium in 3 total defect cases after basal cell carcinoma resection of the lower eyelid. The auricular cartilage was excised in strips with the surrounding perichondrium attached and simultaneously reconstructed, with the auricular cartilage as the tarsal and the perichondrium as the conjunctival substitute. In all 3 cases, good results were obtained without eyelid ectropion or corneal irritation 1 year postoperatively. No auricular deformities were observed. However, partial lower eyelid ptosis was observed in 2 cases. In future cases, correctively over-fixating the lower eyelid morphology is necessary.

Flap Monitoring Using Interstitial Fluid Glucose Measurements.

Background: Various flap monitoring techniques have been used in the early detection of anastomotic thrombus; however, the use of automatic and continuous monitoring methods is presently uncommon. The purpose of this study was to investigate trends in interstitial fluid glucose concentration (IFG) in flap monitoring by measuring IFG automatically and continuously. Methods: Nine patients underwent unilateral breast reconstruction using a transverse rectus abdominis myocutaneous flap with vascular anastomosis. Two IFG measuring devices were attached to each patient. One device was attached to the flap (flap IFG) and the other to the healthy breast (control IFG). In each case, flap IFG, control IFG, and IFG ratio (flap IFG/control IFG) were recorded in the initial 72 h post-surgery (first half) and also in the subsequent 72 h (second half). In all of the cases, the mean values recorded in the first half and those in the second half were compared. Results: All flaps survived. The flap IFG didn't fall below 40 mg/dL in the first half. The minimum flap IFG and IFG ratio were 42 mg/dL and 0.55 in the first half. The flap IFG was significantly higher in the first half than in the second half in all cases, and the IFG ratio was similar in 8 cases. Furthermore, mean flap IFG and mean IFG ratio in all cases in the first half were significantly higher than in the second half. Conclusions: IFG measurements may complement conventional flap monitoring, particularly in the early postoperative period.

Historique: Diverses techniques de surveillance du lambeau sont utilisées pour favoriser le dépistage précoce du thrombus anastomotique, mais peu de méthodes de surveillance automatique et continue sont utilisées en ce moment. La présente étude visait à examiner les tendances du glucose interstitiel (GI) lors de la surveillance du lambeau par une mesure automatique et continue. Méthodologie: Neuf patientes ont subi une reconstruction mammaire unilatérale au moyen d'un lambeau myocutané du grand droit transverse avec anastomose vasculaire. Chaque patiente était dotée de deux dispositifs de mesure du GI. L'un d'eux était fixé au lambeau (GI du lambeau) et l'autre au sein en bonne santé (GI témoin). Dans chaque cas, les chercheurs ont enregistré le GI du lambeau, le GI témoin et le ratio du GI (GI du lambeau/GI témoin) pendant les 72 premières heures suivant l'opération (première moitié), puis pendant les 72 heures suivantes (deuxième moitié). Dans tous les cas, les chercheurs ont comparé les valeurs moyennes enregistrées pendant la première moitié à celles enregistrées pendant la deuxième moitié. Résultats: Tous les lambeaux ont survécu. Le GI du lambeau n'a pas chuté sous 40 mg/dl pendant la première moitié. Le ratio minimal du GI était de 42 mg/dl et 0,55 pendant la première moitié. Dans tous les cas, le GI du lambeau était beaucoup plus élevé pendant la première moitié que pendant la deuxième moitié, et le ratio du GI était semblable dans huit cas. De plus, dans tous les cas, le GI moyen du lambeau et le ratio moyen du GI était beaucoup plus élevé pendant la première moitié que la deuxième. Conclusions: Les mesures de GI peuvent compléter la surveillance habituelle du lambeau, notamment au début de la période postopératoire.

Treatment of Cicatricial Lower Eyelid Ectropion with Suture of Horner Muscle Combined with Fascia Transplantation.

This case series aimed to describe a new technique for correcting contractures and deformities that reliably addresses lacrimal punctum deviation and severe cicatricial lower eyelid ectropion. This was a technical description and a retrospective interventional case series. Eyelid ectropion and lacrimal punctum deviation were treated surgically by grafting the fascia lata and suturing the tarsus-Horner muscle. In total, three patients underwent this surgery: one for burns, one for lower eyelid tumor resection, and the other for an orbital floor fracture following a motorcycle accident, all resulting in ectropion. All patients previously had failed ectropion correction procedures, including scar revision, skin grafting, auricular cartilage grafting, and lateral tarsal strips. The mean follow-up was 15.8 (12.5-18.5) months. Furthermore, all patients showed resolution of lower eyelid ectropion and significant improvement in lower eyelid contracture, with a mean increase of 4.0 (2.5-5) mm. No severe complications were observed, and they reported a significant improvement in ocular surface symptoms. Our study shows that tacking of the tarsus and Horner muscles in combination with fascia lata grafting is effective in correcting refractory cicatricial lower eyelid ectropion with deviation of the tear punctum.

An Extended Kolmogorov-Avrami-Ishibashi (EKAI) Model to Simulate Dynamic Characteristics of Polycrystalline-Ferroelectric-Gate Field-Effect Transistors.

A physics-based model on polarization switching in ferroelectric polycrystalline films is proposed. The calculation results by the model agree well with experimental results regarding dynamic operations of ferroelectric-gate field-effect transistors (FeFETs). In the model, an angle θ for each grain in the ferroelectric polycrystal is defined, where θ is the angle between the spontaneous polarization and the film normal direction. Under a constant electric field for a single-crystal film with θ = 0, phenomena regarding polarization domain nucleation and wall propagation are well described by the Kolmogorov-Avrami-Ishibashi theory. Since the electric fields are time-dependent in FeFET operations and the θ values are distributed in the polycrystalline film, the model in this paper forms an extended Kolmogorov-Avrami-Ishibashi (EKAI) model. Under a low electric field, the nucleation and domain propagation proceed according to thermally activated processes, meaning that switching the time scale of a grain with the angle θ is proportional to an exponential form as exp(const./Ezcosθ) [Ez: the film-normal electric field]. Wide θ distribution makes the time response quite broad even on the logarithmic scale, which relates well with the broad switching time experimentally shown by FeFETs. The EKAI model is physics based and need not assume non-physical distribution functions in it.

Regeneration of Panniculus Carnosus Muscle in Fetal Mice Is Characterized by the Presence of Actin Cables.

Mammalian skin, including human and mouse skin, does not regenerate completely after injury; it is repaired, leaving a scar. However, it is known that skin wounds up to a certain stage of embryonic development can regenerate. The mechanism behind the transition from regeneration to scar formation is not fully understood. Panniculus carnosus muscle (PCM) is present beneath the dermal fat layer and is a very important tissue for wound contraction. In rodents, PCM is present throughout the body. In humans, on the other hand, it disappears and becomes a shallow fascia on the trunk. Fetal cutaneous wounds, including PCM made until embryonic day 13 (E13), regenerate completely, but not beyond E14. We visualized the previously uncharacterized development of PCM in the fetus and investigated the temporal and spatial changes in PCM at different developmental stages, ranging from full regeneration to non-regeneration. Furthermore, we report that E13 epidermal closure occurs through actin cables, which are bundles of actomyosin formed at wound margins. The wound healing process of PCM suggests that actin cables may also be associated with PCM. Our findings reveal that PCM regenerates through a similar mechanism.

Compound 13 Promotes Epidermal Healing in Mouse Fetuses via Activation of AMPK.

Unlike adults, early developing fetuses can completely regenerate tissue, and replicating this could lead to the development of treatments to reduce scarring. Mice epidermal structures, including wound healing patterns, are regenerated until embryonic day (E) 13, leaving visible scars thereafter. These patterns require actin cable formation at the epithelial wound margin through AMP-activated protein kinase (AMPK) activation. We aimed to investigate whether the administration of compound 13 (C13), a recently discovered AMPK activator, to the wound could reproduce this actin remodeling and skin regeneration pattern through its AMPK activating effect. The C13 administration resulted in partial formations of actin cables, which would normally result in scarring, and scar reduction during the healing of full-layer skin defects that occurred in E14 and E15 fetuses. Furthermore, C13 was found to cause AMPK activation in these embryonic mouse epidermal cells. Along with AMPK activation, Rac1 signaling, which is involved in leaflet pseudopodia formation and cell migration, was suppressed in C13-treated wounds, indicating that C13 inhibits epidermal cell migration. This suggests that actin may be mobilized by C13 for cable formation. Administration of C13 to wounds may achieve wound healing similar to regenerative wound healing patterns and may be a potential candidate for new treatments to heal scars.

Corrigendum: Single-cell RNA-seq analysis reveals cellular functional heterogeneity in dermis between fibrotic and regenerative wound healing fates.

[This corrects the article DOI: 10.3389/fimmu.2022.875407.].

A Novel Dissection Method of the Internal Mammary (Thoracic) Artery: Anastomotic Vessel of the DIEP Flap.

Deep inferior epigastric perforator flaps are commonly used for breast reconstruction using autologous tissue. For such free flaps, the internal mammary artery provides stable blood flow as the recipient for anastomosis. We report a novel dissection method of the internal mammary artery. First, the perichondrium and costal cartilage of the sternocostal joint are dissected with electrocautery. Then, the incision on the perichondrium is extended along the cephalic and caudal ends. Next, this C-shaped superficial layer of perichondrium is elevated from the cartilage. The cartilage is incompletely fractured with electrocautery, with the deep layer of perichondrium intact. Then, the cartilage is completely fractured by leverage and removed. The remaining deep layer of perichondrium is incised at the costochondral junction and shifted aside, revealing the internal mammary artery. The preserved perichondrium creates a rabbet joint to protect the anastomosed artery. This method not only enables a more reliable, safer dissection of the internal mammary artery, but also allows reusage of the perichondrium as underlayment in the setting of anastomosis, and coverage for the incised rib edge, protecting the anastomosed vessels.

Fetal Fibroblast Transplantation via Ablative Fractional Laser Irradiation Reduces Scarring.

Scar treatments include fractional laser treatment, cell transplantation, surgery, skin needling, and dermal fillers. Fractional laser treatments are used to reduce scarring and blurring. Cell transplantation is promising, with mature fibroblasts and adipose-derived stem cells being used clinically, while embryonic fibroblasts are used experimentally. Herein, we developed a combination of ablative CO2 (carbon dioxide) fractional laser and cell transplantation for the treatment of scars. Eight-week-old male C57Bl/6 mice were used to create a full-layer skin defect in the back skin and create scars. The scar was then irradiated using a CO2 fractional laser. The cells were then transplanted onto the scar surface and sealed with a film agent. The transplanted cells were GFP-positive murine fetal fibroblasts (FB), fetal fibroblasts with a long-term sphere-forming culture (LS), and fetal skin with a short-term sphere-forming culture (SS). After transplantation, green fluorescent protein (GFP)-positive cells were scattered in the dermal papillary layer and subcutis in all the groups. LS significantly reduced the degree of scarring, which was closest to normal skin. In conclusion, the combination of ablative fractional laser irradiation and fetal fibroblast transplantation allowed us to develop new methods for scar treatment.

Effect of Sonic Hedgehog on the Regeneration of Epidermal Texture Patterns.

Wounds on embryonic mouse fetuses regenerate up to embryonic day (E) 13, but after E14, the pattern is lost and a visible scar remains. We hypothesized that the sonic hedgehog (Shh), which is involved in patterning during development, is involved in the regeneration of texture. Embryos of ICR mice were surgically injured at E13, E14, and E15 and analyzed for the expression of Shh. For external Shh administration, recombinant Shh-containing slow-release beads were implanted in the wounds of mice. In contrast, cyclopamine was administered to wounds of adult mice to inhibit Shh. The expression of Shh was unaltered at E13, whereas it was upregulated in the epidermis of the wound from E14 onward. Implantation of recombinant Shh-containing beads into E13 wounds inhibited skin texture regeneration. Cyclopamine treatment inhibited epithelialization and thickening of the epidermis in the wounds of adult mice. In vitro, Shh promoted proliferation and inhibited the migration of epidermal keratinocytes through the activation of cyclin D proteins. Thus, our results suggested that the expression of Shh is involved in the regeneration of texture during wound healing, especially in epidermal keratinocyte migration and division, and could inhibit skin texture regeneration after E14.

Effect of All-trans Retinoic Acid on Panniculus Carnosus Muscle Regeneration in Fetal Mouse Wound Healing.

The dermal panniculus carnosus (PC) muscle is critical for wound contraction in lower mammals and is a useful model of muscle regeneration owing to its high cellular metabolic turnover. During wound healing in mice, skin structures, including PC, are completely regenerated up to embryonic day (E) 13, but PC is only partially regenerated in fetuses or adult animals after E14. Nevertheless, the mechanisms underlying wound repair for complete regeneration in PC have not been fully elucidated. We hypothesized that retinoic acid (RA) signaling, which is involved in muscle differentiation, regulates PC regeneration. Methods: Surgical injury was induced in ICR mice on E13 and E14. RA receptor alpha (RARα) expression in tissue samples from embryos was evaluated using immunohistochemistry and reverse transcription-quantitative polymerase chain reaction. To evaluate the effects of RA on PC regeneration, beads soaked in all-trans RA (ATRA) were implanted in E13 wounds, and tissues were observed. The effects of RA on myoblast migration were evaluated using a cell migration assay. Results: During wound healing, RARα expression was enhanced at the cut surface in PCs of E13 wounds but was attenuated at the cut edge of E14 PCs. Implantation of ATRA-containing beads inhibited PC regeneration on E13 in a concentration-dependent manner. Treatment of myoblasts with ATRA inhibited cell migration. Conclusions: ATRA inhibits PC regeneration, and decreased RARα expression in wounds after E14 inhibits myoblast migration. Our findings may contribute to the development of therapies to promote complete wound regeneration, even in the muscle.

Downregulation of Lhx2 Markedly Impairs Wound Healing in Mouse Fetus.

Multiple transitions occur in the healing ability of the skin during embryonic development in mice. Embryos up to embryonic day 13 (E13) regenerate completely without a scar after full-thickness wounding. Then, up to E16, dermal structures can be formed, including skin appendages such as hair follicles. However, after E17, wound healing becomes incomplete, and scar formation is triggered. Lhx2 regulates the switch between maintenance and activation of hair follicle stem cells, which are involved in wound healing. Therefore, we investigated the role of Lhx2 in fetal wound healing. Embryos of ICR mice were surgically wounded at E13, E15, and E17, and the expression of Lhx2 along with mitotic (Ki67 and p63) and epidermal differentiation (keratin-10 and loricrin) markers was analyzed. The effect of Lhx2 knockdown on wound healing was observed. Lhx2 expression was not noticed in E13 due to the absence of folliculogenesis but was evident in the epidermal basal layer of E15 and E17 and at the base of E17 wounds, along with Ki67 and p63 expression. Furthermore, Lhx2 knockdown in E15 markedly prolonged wound healing and promoted clear scar formation. Therefore, Lhx2 expression is involved in cell division associated with wound healing and may contribute to scar formation in late embryos.

Actin cable formation and epidermis-dermis positional relationship during complete skin regeneration.

Up to a certain developmental stage, a fetus can completely regenerate wounds in the skin. To clarify the mechanism of fetal skin regeneration, identifying when the skin switches from fetal-type wound regeneration to adult-type wound repair is necessary. We hypothesized that this switch occurs at several time points and that complete skin regeneration requires epidermal-dermal interactions and the formation of actin cables. We compared normal skin and wound morphology at each developmental stage. We examined two parameters: epidermal texture and dermal structure. We found that the three-dimensional structure of the skin was completely regenerated in full-thickness skin incisions made before embryonic day (E) 13. However, the skin texture did not regenerate in wounds made after E14. We also found that the dermal structure regenerates up to E16, but wounds created after E17 heal as scars with dermal fibrosis. By controlling the activity of AMP-activated protein kinase and altering actin cable formation, we could regulate scar formation in utero. These findings may contribute to therapies that allow complete skin regeneration without scarring.

Role of Wnt Signaling in Mouse Fetal Skin Wound Healing.

Wnt proteins secrete glycoproteins that are involved in various cellular processes to maintain homeostasis during development and adulthood. However, the expression and role of Wnt in wound healing have not been fully documented. Our previous studies have shown that, in an early-stage mouse fetus, no scarring occurred after cutaneous wounding, and complete regeneration was achieved. In this study, the expression and localization of Wnt proteins in a mouse fetal-wound-healing model and their associations with scar formation were analyzed. Wnt-related molecules were detected by in-situ hybridization, immunostaining, and real-time polymerase chain reaction. The results showed altered expression of Wnt-related molecules during the wound-healing process. Moreover, scar formation was suppressed by Wnt inhibitors, suggesting that Wnt signaling may be involved in wound healing and scar formation. Thus, regulation of Wnt signaling may be a possible mechanism to control scar formation.

Fibroblast Growth Factor 7 Suppresses Fibrosis and Promotes Epithelialization during Wound Healing in Mouse Fetuses.

Adult mammalian wounds leave visible scars, whereas skin wounds in developing mouse fetuses are scarless until a certain point in development when complete regeneration occurs, including the structure of the dermis and skin appendages. Analysis of the molecular mechanisms at this transition will provide clues for achieving scarless wound healing. The fibroblast growth factor (FGF) family is a key regulator of inflammation and fibrosis during wound healing. We aimed to determine the expression and role of FGF family members in fetal wound healing. ICR mouse fetuses were surgically wounded at embryonic day 13 (E13), E15, and E17. Expression of FGF family members and FGF receptor (FGFR) in tissue samples from these fetuses was evaluated using in situ hybridization and reverse transcription-quantitative polymerase chain reaction. Fgfr1 was downregulated in E15 and E17 wounds, and its ligand Fgf7 was upregulated in E13 and downregulated in E15 and E17. Recombinant FGF7 administration in E15 wounds suppressed fibrosis and promoted epithelialization at the wound site. Therefore, the expression level of Fgf7 may correlate with scar formation in late mouse embryos, and external administration of FGF7 may represent a therapeutic option to suppress fibrosis and reduce scarring.

Single-Cell RNA-seq Analysis Reveals Cellular Functional Heterogeneity in Dermis Between Fibrotic and Regenerative Wound Healing Fates.

Background: Fibrotic scars are common in both human and mouse skin wounds. However, wound-induced hair neogenesis in the murine wounding models often results in regenerative repair response. Herein, we aimed to uncover cellular functional heterogeneity in dermis between fibrotic and regenerative wound healing fates. Methods: The expression matrix of single-cell RNA sequencing (scRNA-seq) data of fibrotic and regenerative wound dermal cells was filtered, normalized, and scaled; underwent principal components analysis; and further analyzed by Uniform Manifold Approximation and Projection (UMAP) for dimension reduction with the Seurat package. Cell types were annotated, and cell-cell communications were analyzed. The core cell population myofibroblast was identified and the biological functions of ligand and receptor genes between myofibroblast and macrophage were evaluated. Specific genes between fibrotic and regenerative myofibroblast and macrophage were identified. Temporal dynamics of myofibroblast and macrophage were reconstructed with the Monocle tool. Results: Across dermal cells, there were six cell types, namely, EN1-negative myofibroblasts, EN1-positive myofibroblasts, hematopoietic cells, macrophages, pericytes, and endothelial cells. Ligand and receptor genes between myofibroblasts and macrophages mainly modulated cell proliferation and migration, tube development, and the TGF-ß pathway. Specific genes that were differentially expressed in fibrotic compared to regenerative myofibroblasts or macrophages were separately identified. Specific genes between fibrotic and regenerative myofibroblasts were involved in the mRNA metabolic process and organelle organization. Specific genes between fibrotic and regenerative macrophages participated in regulating immunity and phagocytosis. We then observed the underlying evolution of myofibroblasts or macrophages. Conclusion: Collectively, our findings reveal that myofibroblasts and macrophages may alter the skin wound healing fate through modulating critical signaling pathways.

Decorin Inhibits Dermal Mesenchymal Cell Migration and Induces Scar Formation.

Background: Variations in skin healing capacities are observed during different murine embryonic developmental stages. Through embryonic day 16 (E16), embryos are able to regenerate dermal architecture following flank skin wounding; however, after E17, wounds heal incompletely, inducing scar formation. The regenerative ability of the E16 fetal dermis depends on the migration of dermal mesenchymal cells. Decorin is a small molecule known to affect tissue tensile strength, cell phenotype, and tissue repair, including skin wound healing. In the current study, we evaluated the expression and roles of decorin in wound healing. Methods: Surgical injury was induced at E16 and E17 in ICR mouse embryos. Decorin expression was evaluated in tissue samples from these embryos using immunohistochemistry and reverse transcription quantitative polymerase chain reaction. Cell migration assays were used to evaluate wound healing capability of separated dermal and fascial tissues. Results: Our results showed that decorin exhibited distinct expression patterns during wound healing at E16 versus E17. Additionally, decorin expression altered cell migration in vitro. Dermal and fascial mesenchymal cells were found to exhibit distinct migration patterns concomitant with altered decorin expression. Specifically, decorin inhibited migration and favored scar formation. Conclusion: Decorin expression may contribute to scar formation in the late stage of mouse embryos by inhibiting the migration of dermal mesenchymal cells.

Screening of Autophagy-Related Prognostic Genes in Metastatic Skin Melanoma.

Cutaneous melanoma refers to a common skin tumor that is dangerous to health with a great risk of metastasis. Previous researches reported that autophagy is associated with the progression of cutaneous melanoma. Nevertheless, the role played by genes with a relation to autophagy (ARG) in the prediction of the course of metastatic cutaneous melanoma is still largely unknown. We observed that thirteen ARGs showed relations to overall survival (OS) in the Cox regression investigation based on a single variate. We developed 2-gene signature, which stratified metastatic cutaneous melanoma cases to groups at great and small risks. Cases suffering from metastatic cutaneous melanoma in the group at great risks had power OS compared with cases at small risks. The risk score, T phase, N phase, and age were proved to be individual factors in terms of the prediction of OS. Besides, the risk scores identified by the two ARGs were significantly correlated with metastatic cutaneous melanoma. Receiver operating characteristic (ROC) curve analysis demonstrated accurate predicting performance exhibited by the 2-gene signature. We also found that the immunization and stromal scores achieved by the group based on large risks were higher compared with those achieved by the group based on small risks. The metastatic cutaneous melanoma cases achieving the score based on small risks acquired greater expression of immune checkpoint molecules as compared with the high-risk group. In conclusion, the 2-ARG gene signature indicated a novel prognostic indicator for prognosis prediction of metastatic cutaneous melanoma, which served as an important tool for guiding the clinical treatment of cutaneous melanoma.

Making the upper edge of a silicone breast implant invisible by fat onlay-grafting harvested from the affected inframammary fold.

BACKGROUND: In silicone breast implant (SBI)-based breast reconstructions, aesthetic outcomes are often low due to the visible upper edge of the SBI. To ameliorate this, grafting fat harvested from the SBI operative field has not been reported to date. Therefore, we aimed to develop a novel technique for fat onlay-grafting, harvested from the inframammary fold (IMF) of the reconstructed breast, and investigate its usefulness. METHODS: A total of 90 patients who underwent SBI-based breast reconstruction after a simple mastectomy were included in this study. The harvested fat was recorded by weight and grafted evenly to the medial and median upper edge of the SBI on the pectoralis major muscle. We applied this technique to 30 patients (fat onlay-grafting group) and compared them with the 60 patients (no-grafting group) who did not undergo our technique using the postoperative 1-year aesthetic outcome scores of the medial and median upper edge of the SBI. Furthermore, we investigated the correlation between the weight of harvested fat and body mass index. RESULTS: No postoperative wound complications occurred, and infection, hardened fat, and fat lysis were not found in the fat onlay-grafting group. The medial and total aesthetic outcome scores in the fat onlay-grafting group were significantly higher than those in the no-grafting group (P<0.05). The average weight of harvested fat was 11.9 [5-32] g. The correlation between the weight of the harvested fat and body mass index was significantly positive (R2=0.7119, P<0.05). CONCLUSIONS: Our technique made the upper edge of the SBI invisible. Further, it was simple and less invasive with safe augmentation. Therefore, we believe that this technique can contribute to better aesthetic outcomes in SBI-based breast reconstruction.