A Novel DNA Aptamer Probe Recognizing Castration Resistant Prostate Cancer in vitro and in vivo Based on Cell-SELEX.

Background: Early recognition of castration-resistant state is of significance for timely adjustment of treatment regimens and improvement of prognosis. Purpose: This study aims to screen new aptamers CRda8 and CRda21 which recognize castration resistant prostate cancer (CRPC) cells with high affinity and specificity by SELEX technology. Methods: The enrichment of specific aptamer candidates was monitored by flow cytometric analysis. The affinity and specificity of aptamer candidates were evaluated by flow cytometry and immunofluorescence assay. MR imaging of CRda21-conjugated polyethylene glycol (PEG)-Fe3O4 nanoparticles to CRPC was further explored in vivo. Results: Both aptamers showed high specificity to target cells with dissociation constants in the nanomolar range, and did not recognize other tested cells. The staining of clinical tissue sections with fluorescent dye labeled aptamers showed that sections from CRPC exhibited stronger fluorescence while sections from benign prostatic hyperplasia and androgen dependent prostate cancer did not exhibit notable fluorescence. In vivo MRI demonstrated that CRda21-conjugated PEG-Fe3O4 had good affinity to CRPC and produced strong T2WI signal intensity reduction distinguished from peritumoral tissue. Conclusion: The high affinity and specificity of CRda8 and CRda21 make the aptamer hold potential for early recognition of castration-resistant state and diagnosis of CRPC at the cellular level.

Activating autophagy promotes skin regeneration induced by mechanical stretch during tissue expansion.

Background: Tissue expansion, a technique in which skin regeneration is induced by mechanical stretch stimuli, is commonly used for tissue repair and reconstruction. In this study, we aimed to monitor the autophagy levels of expanded skin after the application of expansion stimuli and explore the effect of autophagy modulation on skin regeneration. Methods: A rat scalp expansion model was established to provide a stable expanded skin response to mechanical stretch. Autophagy levels at different time points (6, 12, 24, 48 and 72 h after the last expansion) were detected via western blotting. The effect of autophagy regulation on skin regeneration during tissue expansion was evaluated via skin expansion efficiency assessment, western blotting, immunofluorescence staining, TUNEL staining and laser Doppler blood flow imaging. Results: The autophagic flux reached its highest level 48 h after tissue expansion. Activating autophagy by rapamycin increased the area of expanded skin as well as the thicknesses of epidermis and dermis. Furthermore, activating autophagy accelerated skin regeneration during tissue expansion by enhancing the proliferation of cells and the number of epidermal basal and hair follicle stem cells, reducing apoptosis, improving angiogenesis, and promoting collagen synthesis and growth factor secretion. Conversely, the regenerative effects were reversed when autophagy was blocked. Conclusions: Autophagy modulation may be a promising therapeutic strategy for improving the efficiency of tissue expansion and preventing the incidence of the complication of skin necrosis.

Reconstruction of Hemifacial Congenital Giant Nevus with Pre-expanded Scalp Flaps and Deltopectoral Skin Flaps.

BACKGROUND: The hemifacial congenital giant nevus impacts both physical and mental health of the patients. Excision is typically the most suitable option in these situations, but reconstructing the subsequent surgical defects is always a serious challenge. METHODS: Between February 2012 and January 2021, a retrospective review of 4 patients who suffered from hemifacial congenital giant nevus was conducted, and they were treated by pre-expanded scalp flap and deltopectoral flap simultaneously. All patients receive tissue expansion, nevus resection, expanded skin flap transfer, and pedicle division. RESULTS: Four patients with hemifacial congenital giant nevi were successfully treated with no major complications. One patient with a transferred deltopectoral flap experienced distal necrosis of the flap, and healed after dressing changes. No recurrence of the nevus was found during the follow-up period, and the transferred skin flaps match well with facial skin in contour and color. CONCLUSION: This modified pre-expanded scalp flap combined with a deltopectoral flap provides an easy and reliable way for hemifacial reconstruction in patients with a congenital giant nevus.

Macrophage contribution to the survival of transferred expanded skin flap through angiogenesis.

Background: Despite the application of tissue expansion in the reconstruction of significant tissue defects, complications with expanded random-pattern skin flaps remain a major challenge. Insufficient angiogenesis is one of the keys factors in flap ischemia and dysfunction. Macrophages play a key role in promoting tissue angiogenesis, but their effects on expanded flap angiogenesis and the survival of the transferred skin flap are still unknown. Methods: A rat scalp expansion model was established to evaluate the dynamic changes of macrophages in expanded skin. Clodronate liposomes (Clo-lipo) were injected into the expanded scalps to deplete the macrophages, and the expanded scalp flaps with macrophage depletion were orthotopically transferred. The remaining expanded rat scalp flaps were treated with either a macrophage-colony stimulating factor (M-CSF) alone or M-CSF in combination with Clo-lipo and transferred. The number of macrophages, blood perfusion, microvascular densities (MVDs), flap survival, histological changes, and gene expression related to macrophage polarization and angiogenesis were determined with immunofluorescence (IF) staining, full-field laser perfusion imager, hematoxylin and eosin (HE) staining, and quantitative real-time polymerase chain reaction. Results: The number of pan-macrophages significantly increased in the expanded scalp on days 14 and 21 after expander placement. The depletion rate after treatment with Clo-lipo was 29.06%, and the number of macrophages was significantly reduced in the group that underwent Clo-lipo treatment on day 14 before flap transfer (P<0.05). Macrophage depletion resulted in decreased blood perfusion, reduced MVDs, lower expression of factors, and poor survival rate. The recruitment of macrophages with a M-CSF led to higher blood perfusion, increased MVDs, greater expression of angiogenic factors, and better flap survival after flap transfer. Conclusions: Alternatively activated macrophages in the expanded flap could significantly promote angiogenesis, improve blood perfusion, and ultimately increase the flap survival rate. Modulating alternatively activated macrophages may provide a key therapeutic strategy to promote expanded skin flap survival. Our study has provided a basis for clinically improving random-pattern skin flap survival.

Hair-Bearing Expanded Scalp Flap for Total Beard Reconstruction in Patients With Chin and Submental Postburn Scars.

BACKGROUND: Loss of beard in adult male caused by severe burn may cause cosmetic and psychological problems for these patients. Reconstruction of the beard with hair-bearing skin flaps in similar color and texture of the surrounding tissues remains a challenge. METHODS: Eight male patients suffered from submental postburn scar and beard loss were treated by using the hair-bearing expanded scalp flap. A 1000 mL nephroid tissue expander was first implanted under the frontal and mid scalp. After a 3 to 4-month tissue expansion, the expanded hair-bearing scalp flap based on bilateral superficial temporal vessels were raised and transferred for beard reconstruction, and the cutaneous pedicles were curled into tubes. Delay and division of the pedicles were performed 3 to 4 weeks after flap transfer. RESULTS: Eight male patients with postburn scar and beard loss were successfully treated with no major complication. One patient suffered from edge necrosis at distal end of the flap and healed after daily dressing change. Chin and submental areas were repaired by expanded scalp flap and total beard was reconstructed at the same time. All donor sites were closed directly without skin grafting. CONCLUSIONS: The modified expanded bipedicled scalp flap provides an easy and reliable way for total beard reconstruction and large-scale submental scars repairment.

Reconstruction of facial defects using a pre-expanded scalp flap: A description of the method used and outcomes of 43 patients.

Background: A technique for reconstructing facial units with matching colour, similar texture and sufficient contour is ideal for patients with various facial defects. The current report aimed to present the experience of the authors in facial reconstruction using pre-expanded scalp flaps combined with laser hair removal. Methods: From January 2014 to August 2021, 43 patients with different facial defects, such as post-burn scar and congenital nevus, were treated using this surgical technique that involved tissue expansion, scalp flap transfer and laser hair removal. Facial defects were artificially classified into three regions (forehead, n = 19; cheek, n = 15; and lips and chin, n = 9). Pedicle delaying and division were performed in patients who underwent reconstruction with pedicled flaps. Results: Of the included patients, one presented with haematoma, one with infection and three had distal necrosis after expanded scalp flap transfer. The donor site was primarily closed in all patients. Further, all patients were successfully treated without major complications. The texture, colour and contour of the scalp flap after laser hair removal matched well with the surrounding skin tissues at 2-30-month follow-up. Conclusion: Reconstruction using pre-expanded scalp flaps combined with laser hair removal is an effective and reliable option for facial reconstruction with excellent colour and texture match.

Expanded scalp flap combined with laser hair removal to reconstruct facial defects around the hairline.

BACKGROUND: Congenital and acquired facial lesions around the hairline can bring huge physical and psychological trauma to patients. At present, reconstruction of this area remains a challenge. In this study, we present an alternative technique to reconstruct the aesthetic units using an expanded scalp flap combined with laser hair removal. METHODS: We retrospectively reviewed 25 cases of facial lesions around the hairline reconstructed with this surgical technique between May 2014 and May 2020. Expander was implanted under the scalp as designed before the operation. After the expander was fully expanded, the lesion was removed and the scalp flap was transferred. Laser hair removal was performed on the transplanted skin flap 2 weeks after flap transfer. RESULTS: There were ten cases of postburn scar, nine cases of congenital nevus, four cases of traumatic scar, one case of haemangioma, and one case of nevus sebaceous. The median times of laser treatment was 3 (range, 1-8). The median follow-up time was 11 months, ranging from 1 to 27 months. The colour and texture of expanded flaps were similar to adjacent tissue in all cases. The direction of reserved hair in transferred flaps was consistent with the direction of hair in the recipient area or contralateral hair. There were no complications, such as infection, blistering, discolouration, and ulceration. All patients were satisfied with the appearance of the reconstructed hairline and the surgical outcomes. CONCLUSIONS: The expanded scalp flap combined with laser hair removal is a feasible and effective technique to reconstruct both sides of the hairline simultaneously from a single donor site with a good colour match and a similar texture and thickness.

Simultaneous Double Eyelid Blepharoplasty and Blepharoptosis Correction With Levator Aponeurosis Plication Technique: Clinical Experience of 108 Cases.

BACKGROUND: Fifty percent of Asians are born without a supratarsal fold (also called single eyelid), and double eyelid blepharoplasty is one of the most commonly performed and most popular facial cosmetic surgeries in the Asian population. However, patients with single eyelid frequently present with concomitant mild blepharoptosis (degree of ptosis, ≤2 mm), which often fails to cause the attention of surgeons and misses correction. METHODS: A retrospective study of all patients who underwent double eyelid blepharoplasty and blepharoptosis correction simultaneously with the modified levator aponeurosis plication technique was performed from June of 2017 to June of 2020. RESULTS: A total of 108 patients (155 eyelids) underwent double eyelid blepharoplasty and blepharoptosis correction simultaneously with the modified levator aponeurosis plication technique and were enrolled in the study. The average follow-up period was 11.8 ± 4.5 months. There was a statistically significant difference between the preoperative margin reflex distance 1 (MRD1) and postoperative MRD1 (2.93 ± 0.37 vs 4.21 ± 0.39 mm, P = 0.000), and the mean MRD1 improvement was 1.28 ± 0.50 mm. Sufficient correction was obtained in 148 eyelids (95.5%), whereas undercorrection was observed in 5 eyelids (3.2%) and overcorrection was observed in 2 eyelids (1.3%). One hundred two patients (94.4%) were completely satisfied with the final result.All patients had smooth and elegant upper eyelid margin curve, and no patients complained of distortion of the eyelid margin contour and foreign body sensation.There were no cases of hematoma, infection, suture exposure, corneal abrasion, and keratitis in any patient. CONCLUSIONS: This modified levator aponeurosis plication introduced in this study is a simple and effective method for creating double-eyelid crease and correcting mild blepharoptosis simultaneously, and provides a satisfactory outcome. As such, we recommend this method in treating patients with both single eyelid and mild blepharoptosis.

Application of Various Methods to Evaluate the Postoperative Characteristics of Expanded Pedicled Deltopectoral Flap for Large Facial Scars.

ABSTRACT: The expanded pedicled deltopectoral flap (EPDF) has been widely used to repair large facial scars. Although doctors and patients are usually satisfied with the outcomes, the actual functional recovery and cosmetic effects of EPDF are still unknown. It is, therefore, necessary to objectively investigate the effect of transferred EPDF by using a variety of methods. From January 2008 to December 2018, 52 patients who underwent EPDF surgery at Xijing Hospital were enrolled. Sense of touch, static 2-point discrimination, elasticity, and color were measured. Thermesthesia and algesthesia were also tested. Postoperative scars were evaluated using the patient and observer scar assessment scale. Satisfaction of patients, doctors, and laypersons was investigated. The algaesthesis, thalposis, and rhigosis scores were 4.7 ±â€Š0.7, 3.7 ±â€Š0.9, and 4.5 ±â€Š0.8, respectively. The tactile score was 0.3 ±â€Š0.2 mN, and 2-point discrimination was 10.1 ±â€Š4.8 mm. L ∗ , a ∗ hemoglobin, and melanin content of the flaps were significantly different when compared with normal skin ( P   <  0.05). The satisfaction of doctors, patients, and laypersons was 88.5%, 71.2%, and 67.3%, respectively. The higher satisfaction of patients was mainly associated with the smaller color difference between the flap and the surrounding skin, and lower patient and observer scar assessment scale score. These results confirm that excellent functional recovery and reliable cosmetic effects are observed when facial scars are repaired with EPDF. The methods used in this study can be applied to the evaluation of functional recovery and cosmetic outcomes of transferred flaps, which may provide a more comprehensive understanding of flap assessment.

Selection of DNA Aptamers Recognizing EpCAM-Positive Prostate Cancer by Cell-SELEX for in vitro and in vivo MR Imaging.

BACKGROUND: The sensitive and specific detection of pathogenic cells is important in tumor diagnosis at an early stage. Aptamers are short single-stranded oligonucleotides evolved from systematic evolution of ligands by exponential enrichment (SELEX). It has been proved that aptamers can interact with cognate target molecules with high affinity and specificity and have great potential in the development of medical imaging at molecular level. PURPOSE: To select epithelial cell adhesion molecule (EpCAM) specific aptamers targeting prostate cancer and further to conjugate aptamers with GoldMag nanoparticles (a typical iron oxide core/gold shell structure) to construct magnetic molecular probes for medical imaging. METHODS: EpCAM-specific aptamers were selected by Cell-SELEX. The enrichment of specific aptamer candidates was monitored by flow cytometric analysis. Aptamers were further conjugated with GoldMag nanoparticles to construct magnetic molecular probes. The affinity and specificity of aptamer candidates and aptamer-conjugated GoldMag nanoparticles were evaluated. The MR imaging of aptamer-conjugated GoldMag nanoparticles to prostate cancer was further explored in vitro and in vivo. RESULTS: After 12 rounds of selection, aptamer candidates Eppc6 and Eppc14 could specifically target three types of prostate cancer cells, revealing a high affinity of Eppc6 and Eppc14. Moreover, aptamer-conjugated GoldMag nanoparticles not only exhibited good affinity to different prostate cancer cells but also produced strong T2WI signal intensity reduction distinguished from peritumoral tissue in MRI, indicating that the molecular probes possess both the affinity properties of EpCAM-specific aptamer and the superparamagnetic features of iron oxide. CONCLUSION: Our study indicates that aptamer Eppc6 and Eppc14 can recognize prostate cancer cells and tissues. The aptamer-conjugated GoldMag nanoparticles constructed in the study can be used as a molecular imaging agent for detection of PCa in MRI.

Secreted PEDF modulates fibroblast collagen synthesis through M1 macrophage polarization under expanded condition.

Tissue expansion is widely used to obtain new skin tissue for repairing defects in the clinical practice of plastic surgery. One major complication can be dermal thinning during expansion, which usually leads to skin rupture. Collagen synthesis can determine dermal thickness and can be influenced by macrophage polarization during expansion. The aim of the study was to test whether pigment epithelium-derived factor (PEDF) could be a modulator of collagen synthesis in fibroblasts by regulating macrophage polarization during skin expansion. Our results showed that PEDF mRNA expression was increased in expanded human and mouse epidermis. PEDF protein levels were elevated in the subcutaneous exudates of a rat skin expansion model. Increased PEDF mRNA expression was accompanied by dermal thinning during a three-week expansion protocol. Subcutaneous injection of PEDF in vivo further resulted in dermal thinning and cell number increase of M1 macrophage in the expanded skin. PEDF also promoted macrophage polarization in vitro to the M1 subtype under hypoxic conditions. PEDF did not influence collagen gene expression in fibroblasts directly, but attenuated collagen synthesis in a macrophage-mediated manner. Additionally, blockage of PEDF receptors on macrophages with inhibitors rescued collagen synthesis in fibroblasts. Our research demonstrated PEDF elevation in expanded skin leads to dermal thinning through M1 macrophage-mediated collagen synthesis inhibition in fibroblasts. Our results could form a basis for the development of novel strategies to improve skin integrity in expanded skin by using PEDF.

Nuclear Receptor Subfamily 4 Group A Member 1 Overexpression Prolongs Free Flap Allotransplant Graft Survival by Inducing T-Cell Anergy in the Rat.

BACKGROUND: New strategies to inhibit acute rejection are needed for further applications of composite tissue allotransplantation. The nuclear receptor subfamily 4 group A member 1 (NR4A1) is considered a key controller of maintaining tolerance homeostasis. However, the effect of NR4A1 in suppressing rejection responses after allotransplantation remains unknown. METHODS: Brown Norway rat groin flaps were transplanted into Lewis rat recipients. The recipients were administrated cytosporone B, an NR4A1 activator. NR4A1 expression and graft survival time were assessed. T helper type 1 and regulatory T cell populations in the second lymphoid organ were detected by flow cytometry. Furthermore, a retrovirus containing NR4A1 was constructed and transfected to T cells in vitro. After stimulation, interleukin 2 and interferon gamma secretions were detected in the T cells. RESULTS: Administration of cytosporone B activated NR4A1 expression in allotransplant recipients and was associated with prolonged survival time of the vascularized free flap allograft. T helper type 1 cells in the recipient secondary lymphoid organs were decreased, whereas the population of regulatory T cells did not change. Interleukin 2 and interferon gamma were suppressed in vitro in the T cells overexpressing NR4A1. CONCLUSIONS: We demonstrated that the overexpressed NR4A1 is associated with suppressed graft rejection response. The suppression effect may attribute to induction of T-cell anergy and blockade of key immunologic cytokines.

Establishment of a Novel Mouse Model for Soft Tissue Expansion.

BACKGROUND: Despite its increasing use, not much is known about tissue expansion, and its complication rates are significantly high. Thus, there is an urgent need to establish a stable animal model to overcome the limitations and complications of tissue expansion. Although the mouse model has shown several advantages in the in-depth studies, an appropriate mouse expansion model has rarely been reported, likely because of its loose skin. MATERIALS AND METHODS: A micro expander was designed and implanted under the scalp of a mouse (expanded group); sterilized saline was regularly injected into the expander. In sham-operated mice (control group), a silicone sheet was implanted under the scalp. Skin samples were collected 5 wk after surgery. Histologic changes including epidermal and dermal thickness and collagen fiber arrangement were analyzed. In addition, vascular density and cell proliferation ratio were determined. An ultrastructural analysis was also performed. RESULTS: With the application of the expansion device, the skin became tight and showed area enlargement. The epidermal thickness of the expanded skin increased significantly (P < 0.01), whereas the thickness of the dermis decreased significantly (P < 0.05) as compared with the control skin. Masson staining demonstrated that collagen bundles were arranged more compactly in the expanded skin (P < 0.05) than in the controls. Furthermore, more proliferating cells (P < 0.05) and blood vessels (P < 0.01) were observed. Transmission electron microscopy showed that the fibers of expanded skin were stretched and broken into bundles of various diameters, with abundant active fibroblasts. CONCLUSIONS: A reliable mouse model of scalp skin expansion was successfully established, which may be a promising tool for in-depth studies on skin soft tissue expansion.

Macrophages are necessary for skin regeneration during tissue expansion.

BACKGROUND: Tissue expansion is a procedure that promotes skin regeneration by mechanical stretch. During the stress and relaxation cycle, the skin undergoes a repeated microtrauma which triggers an immune response leading to the recruitment of macrophages to repair the damaged tissue. Macrophages have been found to be necessary for tissue repair and wound healing, but their effects on skin regeneration during mechanical stretch remain unclear. METHODS: The dynamic changes of macrophages in the rat skin tissues undergoing expansion were quantitatively determined by immunohistochemistry staining. The area of the expanded skin, skin thickness, dermal collagen density, cell proliferation and tissue vascularization were examined to determine the effects of macrophages on the expanding skin. The phenotypes of macrophages and the growth factors related to skin regeneration were also examined to evaluate the underlying mechanisms for the involvement of macrophages in skin regeneration. As a comparison, the tissue samples of expanding skin in which the macrophages were depleted by topically utilizing clodronate liposomes were also evaluated. RESULTS: The number of skin macrophages in skin maintained in the high level during the skin expansion compared to non-expanded skin. We found that a switch from an M1- to M2-dominant response during tissue expansion. After the macrophages were depleted, the skin regeneration was inhibited, as evidenced by a smaller expansion area, thinner skin layers and decreased cell proliferation rate, collagen synthesis and, skin vascularization. The secretion of epidermal growth factor (EGF), fibroblast growth factor (FGF), and vascular endothelial growth factor (VEGF) were decreased when macrophages were depleted. CONCLUSIONS: Our findings suggest that macrophages are necessary for skin regeneration during tissue expansion. Modulating inflammation may provide a key therapeutic strategy to promote skin growth under mechanical strain.

ECDI-fixed donor splenocytes prolong skin allograft survival by promoting M2 macrophage polarization and inducing regulatory T cells.

Rejection is a common complication of allogeneic tissue transplantation. Fixation of splenocytes (SP) with 1-ethyl-3-(3'-dimethylaminopropyl)-carbodiimide (ECDI) induces immune tolerance in recipients post-transplantation; however, the mechanism underlying this effect remains unclear. Here, we determined the mechanisms of ECDI-fixed donor SP (ECDI-SP) in inducing tolerance in skin allograft transplantation. C57BL/6-recipient mice that received Balb/c full-thickness skin transplants with two infusions of donor-derived ECDI-SP, along with rapamycin showed superior skin allograft survival and lower inflammatory cell infiltration than mice that received rapamycin-only treatment. In ECDI-SP-treated mice, the levels of anti-inflammatory cytokines such as interleukin (IL)-10 in sera were markedly increased, whereas the expression of inflammatory cytokines was significantly suppressed. Splenic macrophages were significantly polarized to the alternative activated macrophage (M2) phenotype, with expansion of CD4+Foxp3+ regulatory T cells (Tregs) in the spleen and draining lymph nodes. Allostimulatory activity of ECDI-SP in vitro and donor-specific ex vivo hyporesponsiveness were observed. C57BL/6 macrophages engulfed allogeneic Balb/c-derived ECDI-SP, polarized to the M2 phenotype, with pronounced cAMP response element-binding (CREB) protein phosphorylation. By facilitating increased IL-10 expression, ECDI-SP induced M2 polarization and Treg production, inhibiting effector T-cell proliferation. Thus, ECDI-SP modulates macrophage M2 polarization by increasing CREB phosphorylation and promoting Treg production to suppress allogeneic skin graft rejection.

Use of expanded deltopectoral skin flaps for facial reconstruction after sizeable benign tumor resections.

The overall unsightliness of expansive benign facial tumors imposes both physical and mental suffering. Although excision is generally the optimal recourse in such instances, reconstructing the subsequent surgical defects is always a critical issue. Herein, we have described our experiences using expanded deltopectoral skin flaps to manage large facial wounds after excising benign tumors. Our endeavor called for retrospective review of 22 patients presenting between July 2007 and March 2017 with various facial growths, including hemangiomas, nevi, and neurofibromas. Depending upon areas of facial involvement, unilateral or bilateral deltopectoral skin flaps were expanded. The stepwise process was as follows: expander implantation, flap transfer, pedicle delay, and eventual separation. Ultimately, all 22 patients undergoing this procedure expressed satisfaction with the results in terms of skin texture, color, and flexibility. This particular method may thus be a reasonable choice for repairing sizeable defects in the wake of benign facial tumor excisions.

The Combination of Expanded Scalp Flap and 800 nm Diode Laser in the Reconstruction of Forehead Defect.

Skin grafting is often the first choice for closing forehead defects. However, the aesthetics of skin grafting-reconstructed forehead defects are still not accepted by a large number of patients. With the technological advancement of laser hair removal, scalp flaps have been considered as donors for reconstruction of forehead defects. We evaluated 10 cases of forehead defect reconstructions with expanded scalp flaps followed by hair removal by an 800 nm diode laser. All flaps survived uneventfully and underwent 4-6 laser treatments for hair removal. The appearances of the reconstructed foreheads were similar to that of the adjacent skin, and all patients were satisfied with the treatment outcomes during the 6-24 months of follow-up. It is concluded that the combined treatments of expanded scalp flaps and diode laser hair removal are effective for repairing forehead defects.Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Transfusion of ethylene carbodiimide-fixed donor splenocytes prolongs survival of vascularized skin allografts.

BACKGROUND: Allograft rejection is a major obstacle to the widespread clinical application of vascularized composite allotransplantation. Recent studies revealed a noncytoreductive strategy to protect allografts by the transfusion of ethylene carbodiimide-fixed donor splenocytes (ECDI-SPs). To determine whether this approach offers advantages in protecting skin allografts, we examined the immunological protection of infusing ECDI-SPs with a 30-d administration of rapamycin on the skin allografts of mice. MATERIALS AND METHODS: C57BL/6 recipient mice received BALB/c donor full-thickness skin or vascularized skin transplants at day 0, along with the infusion of donor ECDI-SPs 7 d before and 1 d after allotransplantation and a 30-d course of rapamycin. Recipients received ECDI-untreated splenocytes or C3H allografts as controls. In vitro allostimulatory activity of ECDI-SPs and donor-specific ex vivo hyporesponsiveness were tested. Production of related cytokines (TGF-ß, IL-10, IL-1ß, and TNF-α) and expression of CD4+Foxp3+ regulatory T cells (Tregs) were also examined. RESULTS: Transfusion of ECDI-SPs combined with rapamycin significantly prolonged survival of full-thickness skin (median survival time [MST]: 28 d) and full-thickness skin allografts (MST: 71 d) compared with untreated splenocytes (MSTs: 11 d and 30 d) or C3H allografts (MSTs: 11 d and 38 d). This effect was accompanied by increased production of IL-10 and TGF-ß, decreased production of IL-1ß and TNF-α, and expansion of Tregs in vitro and in vivo. CONCLUSIONS: ECDI-SP infusion combined with short-term rapamycin administration provides a promising approach to prolong the skin allograft survival.

A Mouse Model of Vascularized Skin Transplantation.

BACKGROUND: Allogeneic skin tissues are highly antigenic and induce intensive immune rejection after composite tissue allotransplantation. Mouse models have advantages in mechanistic studies of immune rejection. However, due to technical challenge in vascular anastomosis with suture technique, mouse vascularized skin allotransplantation models are not widely used in studies of immune rejection. Therefore, the authors propose vascular anastomosis through cuff technique during allotransplantation of mouse donor free groin skin flaps to either recipient inguinal or cervical site. METHODS: Free groin skin flaps from BALB/c or C57BL/6 donor mice were transplanted to the groin (inguinal vascularized skin transplantation [IVST]) or to the neck of recipient sites (cervical vascularized skin transplantation [CVST]) of C57BL/6 mice. A nonsuture cuff technique was utilized to anastomose the donor vessels with either femoral vessels in IVST recipients or common carotid arteries and external jugular veins in CVST mice. Immunosuppressant drugs were used in the allogeneic skin group. RESULTS: The overall success rate was higher in the CVST (88.5%) when compared with the IVST (78.9%). Total operation time in CVST mice lasted 96 minutes (95% confidence interval, 92-101 minutes) that was shorter than that for IVST mice (136 minutes, 95% confidence interval, 127-176 minutes; P < 0.01). Complications, such as hindlimb necrosis and self-mutilation, were observed in IVST mice. Rapamycin (3 mg/kg, daily) significantly prolonged vascularized skin allografts survival with median survival time of 80 days. All syngeneic grafts survived for more than 80 days. CONCLUSIONS: We developed a novel mouse vascularized skin transplantation model that is feasible for the study of clinically relevant skin rejection and tolerance.