Molecular pathophysiology of secondary lymphedema.

Lymphedema occurs as a result of lymphatic vessel damage or obstruction, leading to the lymphatic fluid stasis, which triggers inflammation, tissue fibrosis, and adipose tissue deposition with adipocyte hypertrophy. The treatment of lymphedema is divided into conservative and surgical approaches. Among surgical treatments, methods like lymphaticovenular anastomosis and vascularized lymph node transfer are gaining attention as they focus on restoring lymphatic flow, constituting a physiologic treatment approach. Lymphatic endothelial cells form the structure of lymphatic vessels. These cells possess button-like junctions that facilitate the influx of fluid and leukocytes. Approximately 10% of interstitial fluid is connected to venous return through lymphatic capillaries. Damage to lymphatic vessels leads to lymphatic fluid stasis, resulting in the clinical condition of lymphedema through three mechanisms: Inflammation involving CD4+ T cells as the principal contributing factor, along with the effects of immune cells on the VEGF-C/VEGFR axis, consequently resulting in abnormal lymphangiogenesis; adipocyte hypertrophy and adipose tissue deposition regulated by the interaction of CCAAT/enhancer-binding protein α and peroxisome proliferator-activated receptor-γ; and tissue fibrosis initiated by the overactivity of Th2 cells, leading to the secretion of profibrotic cytokines such as IL-4, IL-13, and the growth factor TGF-ß1. Surgical treatments aimed at reconstructing the lymphatic system help facilitate lymphatic fluid drainage, but their effectiveness in treating already damaged lymphatic vessels is limited. Therefore, reviewing the pathophysiology and molecular mechanisms of lymphedema is crucial to complement surgical treatments and explore novel therapeutic approaches.

Breast Reconstruction after Breast Implant-Associated Anaplastic Large Cell Lymphoma Treatment: A Case Report and Literature Review.

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a T-cell non-Hodgkin's lymphoma that occurs in patients with at least one prior textured breast implant. BIA-ALCL has a relatively good prognosis when treated promptly. However, data on the methods and timing of the reconstruction process are lacking. Herein, we report the first case of BIA-ALCL in Republic of Korea in a patient who underwent breast reconstruction using implants and an acellular dermal matrix (ADM). A 47-year-old female patient was diagnosed with BIA-ALCL stage IIA (T4N0M0) and underwent bilateral breast augmentation using textured breast implants. She then underwent removal of both breast implants, total bilateral capsulectomy, adjuvant chemotherapy, and radiotherapy. There was no evidence of recurrence at 28 months postoperatively; therefore, the patient wished to undergo breast reconstruction surgery. A smooth surface implant was used to consider the patient's desired breast volume and body mass index. The right breast was reconstructed with a smooth surface implant and an ADM in the prepectoral plane. Breast augmentation was performed on the left breast using a smooth surface implant. The patient was satisfied with the results and recovered fully with no complications.

Long-Term Ultrasonographic and Histologic Changes in Acellular Dermal Matrix in Implant-Based Breast Reconstructions.

BACKGROUND: Acellular dermal matrix (ADM) is composed of extracellular matrix (ECM) and is widely used in implant-based breast reconstructions. However, long-term changes in the ADM around implants have not been established. This study aimed to investigate long-term changes in the ADM covering breast implants using serial ultrasound and histologic evaluations. METHODS: The authors evaluated the ultrasound results of 145 patients who underwent implant-based breast reconstructions with ADM coverings. The ultrasound results obtained within 18 months of surgery and those obtained 5 years postoperatively were analyzed to determine the change in ADM thickness. For histologic analysis, the ADM was harvested from 30 patients who underwent secondary breast surgery. Histologic features of the ECM and cellular components within the ADM were compared at specific intervals from ADM implantation and the second operation (early ADM group, <18 months; late ADM group, >5 years postoperatively). RESULTS: The ADM thickness on ultrasound examination was significantly decreased in the late ADM group compared with that in the early ADM group ( P < 0.001). Histologic analyses revealed that the late ADM group had less thickness with lower ECM levels versus the early ADM group. Increased infiltration of host cells, such as vascular endothelial cells, myofibroblasts, and immune cells, occurred in the late ADM group. CONCLUSIONS: Implanted ADMs underwent gradual thinning over time, in addition to ECM reduction and infiltration of host cells. These findings are useful in understanding the natural course of ADMs currently used in implant-based breast reconstructions. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Implantation and tracing of green fluorescent protein-expressing adipose-derived stem cells in peri-implant capsular fibrosis.

BACKGROUND: Adipose-derived stem cells (ASCs) have been reported to reduce fibrosis in various tissues. In this study, we investigated the inhibitory role of ASCs on capsule formation by analyzing the histologic, cellular, and molecular changes in a mouse model of peri-implant fibrosis. We also investigated the fate and distribution of ASCs in the peri-implant capsule. METHODS: To establish a peri-implant fibrosis model, customized silicone implants were inserted into the dorsal site of C57BL/6 wild-type mice. ASCs were harvested from the fat tissues of transgenic mice that express a green fluorescent protein (GFP-ASCs) and then injected into the peri-implant space of recipient mice. The peri-implant tissues were harvested from postoperative week 2 to 8. We measured the capsule thickness, distribution, and differentiation of GFP-ASCs, as well as the cellular and molecular changes in capsular tissue following ASC treatment. RESULTS: Injected GFP-ASCs were distributed within the peri-implant capsule and proliferated. Administration of ASCs reduced the capsule thickness, decreased the number of myofibroblasts and macrophages in the capsule, and decreased the mRNA level of fibrogenic genes within the peri-implant tissue. Angiogenesis was enhanced due to trans-differentiation of ASCs into vascular endothelial cells, and tissue hypoxia was relieved upon ASC treatment. CONCLUSIONS: We uncovered that implanted ASCs inhibit capsule formation around the implant by characterizing a series of biological alterations upon ASC treatment and the fate of injected ASCs. These findings highlight the value of ASCs for future clinical applications in the prevention of capsular contracture after implant-based reconstruction surgery.

Effects of an Antiadhesive Agent on Capsule Formation in Implant-Based Breast Reconstruction: A Randomized Controlled Trial.

BACKGROUND: Although implant-based breast reconstruction is a common surgical modality, a periprosthetic capsule inevitably forms and worsens in cases of postmastectomy radiation therapy. Previous animal studies have reported that antiadhesive agents (AAAs) inhibit periprosthetic capsule formation. The authors prospectively examined the clinical effects of an AAA (Mediclore) on capsule formation in implant-based breast reconstruction. METHODS: The authors analyzed patients who underwent immediate two-stage implant-based breast reconstruction following total mastectomy for breast malignancy between November of 2018 and March of 2019. Each patient was randomly allocated to the control or AAA group. After inserting the breast expander and acellular dermal matrix, AAA was applied around the expander before skin closure. The capsule specimen was obtained during the expander-implant change; capsule thickness and immunohistochemistry were investigated. RESULTS: A total of 48 patients were enrolled and allocated to the control ( n = 22) and AAA ( n = 26) groups. There were no significant differences in patient- and operation-related characteristics. Submuscular capsule thickness was significantly reduced in the AAA group compared with the control group. The levels of pro-capsular-forming cells (myofibroblasts, fibroblasts, and M1 macrophages) in the capsule were significantly lower in the AAA group than in the control group. CONCLUSIONS: AAA reduced the thickness of periprosthetic capsules and changed the profiles of cells involved in capsule formation during the tissue expansion. These findings demonstrate the clinical value of AAA for mitigating capsule formation in implant-based breast reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

Engineering of hybrid spheroids of mesenchymal stem cells and drug depots for immunomodulating effect in islet xenotransplantation.

Immunomodulation is an essential consideration for cell replacement procedures. Unfortunately, lifelong exposure to nonspecific systemic immunosuppression results in immunodeficiency and has toxic effects on nonimmune cells. Here, we engineered hybrid spheroids of mesenchymal stem cells (MSCs) with rapamycin-releasing poly(lactic-co-glycolic acid) microparticles (RAP-MPs) to prevent immune rejection of islet xenografts in diabetic C57BL/6 mice. Hybrid spheroids were rapidly formed by incubating cell-particle mixture in methylcellulose solution while maintaining high cell viability. RAP-MPs were uniformly distributed in hybrid spheroids and sustainably released RAP for ~3 weeks. Locoregional transplantation of hybrid spheroids containing low doses of RAP-MPs (200- to 4000-ng RAP per recipient) significantly prolonged islet survival times and promoted the generation of regional regulatory T cells. Enhanced programmed death-ligand 1 expression by MSCs was found to be responsible for the immunomodulatory performance of hybrid spheroids. Our results suggest that these hybrid spheroids offer a promising platform for the efficient use of MSCs in the transplantation field.

Dll4 Inhibition Promotes Graft Retention in Fat Grafting Enriched with Adipose-Derived Stem Cells.

Autologous fat grafting is among the safest and most effective treatments for soft-tissue restoration and augmentation, and many efforts have been made to improve its efficiency, including adipose-derived stem cell (ASC) supplementation. Here, we investigated the role of Notch ligand Delta-like ligand 4 (Dll4) in angiogenesis within grafted fat and its effect on graft retention, as well as the effect of Dll4 inhibition on ASC supplementation. Using a murine fat graft model, we investigated the expression of Dll4 in fat grafts and assessed the graft volume, vascularity, and perfusion within the graft, and ASC differentiation patterns depending on the blockade of Dll4. The underlying mechanism of Dll4 inhibition on ASC supplemented fat grafts was investigated using transcriptome analysis. Dll4 was highly expressed in vascular endothelial cells (ECs) within grafted fat, where Dll4-blocking antibody treatment-induced angiogenesis, promoting fat graft retention. In addition, its effect on fat graft retention was synergistically improved when ASCs were concomitantly supplemented. The expression of junctional proteins was increased in ECs, and inflammatory processes were downregulated in grafted fat upon ASC supplementation and Dll4 inhibition. Dll4 inhibition induced vascularization within the grafted fat, thereby promoting graft retention and exhibiting synergistic effects with concomitant ASC supplementation. This study serves as a basis for developing new potential therapeutic approaches targeting Dll4 to improve graft retention after cell-assisted transfer.

Prevention of Abdominal Bulging Using Onlay Dermal Autografts from Discarded Zone IV TRAM Flap Tissue.

While the transverse rectus abdominis myocutaneous (TRAM) flap is a popular option for abdominal-based breast reconstruction, abdominal wall morbidities such as bulging or hernia remain a concern. Here, we introduced a surgical technique for reinforcing the abdominal wall using an onlay autograft obtained from discarded zone IV tissue following a primary closure. We compared abdominal wall morbidities between patients receiving an onlay graft and those receiving primary closure only. We retrospectively reviewed the medical charts of patients who underwent breast reconstruction using a TRAM flap between December 2018 and May 2021. Additionally, we assessed donor-site morbidities based on physical examination. Of the 79 patients included, 38 had received a dermal graft and 41 had not. Donor-site morbidities occurred in 10 (24.5%) and 1 (2.6%) patients, and bulging occurred in 8 (19.5%) and 1 (2.6%) patients in the primary closure and dermal autograft groups, respectively. A statistically significant difference in the incidence of bulging was observed between the groups (p = 0.030). In conclusion, the introduction of a dermal autograft after primary closure can successfully ameliorate morbidities at the TRAM flap site.

Abnormal Ultrasonographic Findings of Acellular Dermal Matrix in Implant-Based Breast Reconstruction: Correlations with Histopathology.

BACKGROUND: Acellular dermal matrix (ADM) in implant-based breast reconstruction can show various ultrasound (US) findings. However, there are limited reports on the US features of the ADM. The aims of this study were to evaluate US findings of the ADM in implant-based breast reconstruction and correlate them with histopathological findings. METHODS: Between January 2015 and August 2020, 250 women who underwent implant-based breast reconstruction with ADM and a breast US examination at 6 months to 1 year after reconstruction were retrospectively analyzed. Abnormal US findings were classified as type 1 (focal thickening with decreased echogenicity), 2 (diffusely hyperechoic), or 3 (bright echogenic spots). ADM biopsy was performed in 33 patients who underwent second stage or revisional surgeries. RESULTS: In total, 176 consecutive women with 207 US findings were analyzed. The US findings were normal in 52.2% of the women. The percentages of type 1, 2, and 3 patients were 13.5%, 11.1%, and 23. 2%, respectively. These patients had microscopic findings that showed patchy areas with chronic inflammatory infiltrates, dense collagen bundles without degenerative or inflammatory changes, and empty spaces or degenerated foci unaccompanied by inflammation. CONCLUSION: Knowing the various ADM presentations on US can help avoid unnecessary invasive procedures.

Extensive calcific myonecrosis of the lower leg treated with free tissue transfer.

Calcific myonecrosis is a rare condition in which hypoperfusion due to compartment syndrome causes soft tissue and muscle to become calcified. As calcific myonecrosis gradually deteriorates, secretions steadily accumulate inside the affected area, forming a cavity that is vulnerable to infection. Most such cases progress to chronic wounds that are unlikely to heal spontaneously. After removing the calcified tissue, the wound can be treated by primary closure, flap coverage, or a skin graft. In this case, a 72-year-old man had extensive calcific myonecrosis on his left lower leg, and experienced swelling and increasing tenderness. After removing the muscle calcification, we combined two anterolateral thigh free flaps, which were harvested from the patient's right and left thigh, respectively, to reconstruct the wound with a dead-space filler and skin-defect cover at the same time. The patient recovered without revision surgery or major complications.

Compact Fat Grafting: A Novel Method to Improve Graft Retention Through Modulation of Adipocyte Size.

BACKGROUND: The viable zone where adipocytes and/or adipose-derived stem cells survive is present at the surface of graft fat tissue; however, there is controversy regarding the zone thickness. Graft retention could be improved if more adipocytes are included in the zone. OBJECTIVES: We hypothesize that a temporary reduction in adipocyte size prior to grafting could increase the number of adipocytes in the viable zone. We reduced the adipocyte size by treatment with MLN4924, which controls lipid accumulation in adipocytes, and investigated the histological and microenvironmental changes in grafted fat. METHODS: Subcutaneous fat harvested from wild-type C57BL/6J mice was chopped into small pieces; treated with dimethyl sulfoxide (control group), 0.25 µM MLN4924, or 0.5 µM MLN4924 for 4 days; and grafted into recipient C57BL/6J mice at the supraperiosteal plane of the skull. RESULTS: The reduced adipocyte size in response to MLN4924 treatment was restored within 8 weeks after fat grafting. The MLN4924-treated groups exhibited substantially greater graft volume, lower tissue hypoxia, and higher production of M2 macrophages compared with the control group. CONCLUSIONS: Grafting with compact fat that had smaller adipocytes improved the microenvironment by modulating tissue hypoxia and macrophage polarization, leading to improved graft retention. Therefore, compact fat grafting may offer a new clinical strategy without the need for stem cell manipulation.

Analysis of the Molecular Signature of Breast Implant-Associated Anaplastic Large Cell Lymphoma in an Asian Patient.

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL)-a new category of anaplastic large cell lymphoma associated with textured breast implants-has a distinct variation in incidence and is especially rare in Asia. We report the first case of BIA-ALCL in Korea and present its histological and genetic characteristics. A 44-year-old female patient presented with a typical clinical course and symptoms, including breast augmentation with textured breast implants, late-onset peri-implant effusion, and CD30+ALK- histology, followed by bilateral implant removal and total capsulectomy. For histological analysis, we performed immunohistochemistry of the bilateral breast capsules. For transcriptome analysis, we identified highly upregulated gene sets employing RNA-sequencing and characterized the lymphoma immune cell components. In the lymphoma-associated capsule, CD30+ cells infiltrated not only the lymphoma lesion but also the peritumoral lesion. The morphologies of the myofibroblasts and vessels in the peritumoral lesion were similar to those in the tumoral lesion. We observed strong activation of the JAK/STAT3 pathway and expression of programmed death ligand-1 in the lymphoma. Unlike the molecular profiles of BIA-ALCL samples from Caucasian patients-all of which contained activated CD4+ T cells-the Asian patient's profile was characterized by more abundant CD8+ T cells. This study contributes to a better understanding of the pathogenesis and molecular mechanisms of BIA-ALCL in Asian patients that will ultimately facilitate the development of clinical therapies.

Dll4 Blockade Promotes Angiogenesis in Nonhealing Wounds of Sox7-Deficient Mice.

Objective: This study aimed to elucidate the role of the proangiogenic transcription factors Sox7 and Sox17 in the wound healing process and investigate the therapeutic potential of Dll4 blockade, which is an upstream regulator of Sox17, for the treatment of nonhealing wounds. Approach: After generating a full-thickness skin defect wound model of endothelial Sox7- and/or Sox17-deficient mice, we measured the wound healing rates and performed histological analysis. The effects of an anti-Dll4 antibody on wound angiogenesis in Sox7-deficient mice and db/db diabetic mice were assessed. Results: Sox7 and/or Sox17 deletion delayed wound healing. Moreover, the loss of Sox7 and Sox17 inhibited wound angiogenesis, without affecting the expression of the other. Of interest, after anti-Dll4 antibody treatment, Sox17 levels were increased and the suppression of angiogenesis was alleviated in Sox7-deficient mice and db/db diabetic mice. Consequently, Dll4 blockade effectively recovered the observed delay in wound healing. Innovation: The proangiogenic role of Sox7 and Sox17 in wound angiogenesis was addressed and effective treatment of nonhealing wounds by Dll4 blockade was suggested. Conclusion: This study revealed the proangiogenic role of the transcription factors Sox7 and Sox17 in wound angiogenesis. Furthermore, we suggest a novel method for treating nonhealing wounds by particularly targeting the Dll4-Sox17 axis.

Dll4 Suppresses Transcytosis for Arterial Blood-Retinal Barrier Homeostasis.

RATIONALE: Central nervous system has low vascular permeability by organizing tight junction (TJ) and limiting endothelial transcytosis. While TJ has long been considered to be responsible for vascular barrier in central nervous system, suppressed transcytosis in endothelial cells is now emerging as a complementary mechanism. Whether transcytosis regulation is independent of TJ and its dysregulation dominantly causes diseases associated with edema remain elusive. Dll4 signaling is important for various vascular contexts, but its role in the maintenance of vascular barrier in central nervous system remains unknown. OBJECTIVE: To find a TJ-independent regulatory mechanism selective for transcytosis and identify its dysregulation as a cause of pathological leakage. METHODS AND RESULTS: We studied transcytosis in the adult mouse retina with low vascular permeability and employed a hypertension-induced retinal edema model for its pathological implication. Both antibody-based and genetic inactivation of Dll4 or Notch1 induce hyperpermeability by increasing transcytosis without junctional destabilization in arterial endothelial cells, leading to nonhemorrhagic leakage predominantly in the superficial retinal layer. Endothelial Sox17 deletion represses Dll4 in retinal arteries, phenocopying Dll4 blocking-driven vascular leakage. Ang II (angiotensin II)-induced hypertension represses arterial Sox17 and Dll4, followed by transcytosis-driven retinal edema, which is rescued by a gain of Notch activity. Transcriptomic profiling of retinal endothelial cells suggests that Dll4 blocking activates SREBP1 (sterol regulatory element-binding protein 1)-mediated lipogenic transcription and enriches gene sets favorable for caveolae formation. Profiling also predicts the activation of VEGF (vascular endothelial growth factor) signaling by Dll4 blockade. Inhibition of SREBP1 or VEGF-VEGFR2 (VEGF receptor 2) signaling attenuates both Dll4 blockade-driven and hypertension-induced retinal leakage. CONCLUSIONS: In the retina, Sox17-Dll4-SREBP1 signaling axis controls transcytosis independently of TJ in superficial arteries among heterogeneous regulations for the whole vessels. Uncontrolled transcytosis via dysregulated Dll4 underlies pathological leakage in hypertensive retina and could be a therapeutic target for treating hypertension-associated retinal edema.

Big Data Statistical Analysis of Facial Fractures in Korea.

BACKGROUND: The big data provided by Health Insurance Review and Assessment (HIRA) contains data from nearly all Korean populations enrolled in the National Health Insurance Service. We aimed to identify the incidence of facial fractures and its trends in Korea using this big data from HIRA. METHODS: We used the Korean Standard Classification of Disease and Cause of Death 6, 7 for diagnosis codes. A total of 582,318 patients were included in the final analysis. All statistical analyses were performed using SAS software and SPSS software. RESULTS: The incidence of facial fractures consistently declined, from 107,695 cases in 2011 to 87,306 cases in 2016. The incidence of facial fractures was the highest in June 2011 (n = 26,423) and lowest in January 2014 (n = 10,282). Nasal bone fractures were the most common, followed by orbit and frontal sinus fractures. The percentage of nasal bone fractures declined, whereas those of orbital fractures increased from 2011 to 2016 (P < 0.001). Among orbital fractures, inferior wall fractures were the most common, followed by medial wall fractures. Among mandibular fractures, angle fractures were the most common, followed by condylar process and symphysis fractures. Although it was difficult to predict the most common type of zygomatic and maxilla fractures, their incidence consistently declined since 2011. CONCLUSION: We observed trends in facial fractures in Korea using big data including information for nearly all nations in Korea. Therefore, it is possible to predict the incidence of facial fractures. This study is meaningful in that it is the first study that investigated the incidence of facial fractures by specific type.

Single-stage cross-facial nerve grafting has a result equivalent to that of two-stage cross-facial nerve grafting.

BACKGROUNDS: Cross-face nerve grafting (CFNG) is an important treatment for patients with facial palsy. Currently, two-stage CFNG is frequently performed. CFNG is performed first, followed by coaptation when innervation reaches the grafted nerve ending. The present study compared single-stage CFNG with conventional two-stage CFNG. METHODS: We retrospectively reviewed data of 17 patients who underwent CFNG with zygomatic and buccal branch with hypoglossal crossover. Patients with single-stage (group 1) and two-stage (group 2) CFNG were comparatively analyzed 2 years postoperatively. There were nine and eight patients in groups 1 and 2, respectively. The patient's perioperative status was measured with imaging and animation using the Yanagihara grade, altitude, and angle differences of the oral commissure and eye closure. RESULTS: Patients in group 1 could recognize their first postoperative spontaneous movement earlier than those in group 2 (268.3 ± 25.1 days vs. 327.5 ± 51.3 days, respectively, p = 0.015). The Yanagihara grade significantly improved for patients in both groups postoperatively (group 1: 12.8 ± 5.5 to 25.3 ± 6.1, p < 0.01; group 2: 12.4 ± 5.6 to 24.3 ± 5.0, p = 0.012). Height and angle difference of the oral commissure showed a significant improvement during resting and smiling in both groups. Eye closure also showed significant improvement in both groups (group 1: 4.1 ± 0.6 to 2.6 ± 0.5, p < 0.01; group 2: 4.0 ± 0.5 to 2.8 ± 0.7, p < 0.01). There was no significant difference in the postoperative improvement rate between the groups. CONCLUSIONS: Single-stage CFNG shows results equivalent to those of two-stage CFNG. Single-stage CFNG is associated with a shorter treatment period and fewer operations.