Depletion of donor dendritic cells ameliorates immunogenicity of both skin and hind limb transplants.

Acute cellular rejection remains a significant obstacle affecting successful outcomes of organ transplantation including vascularized composite tissue allografts (VCA). Donor antigen presenting cells (APCs), particularly dendritic cells (DCs), orchestrate early alloimmune responses by activating recipient effector T cells. Employing a targeted approach, we investigated the impact of donor-derived conventional DCs (cDCs) and APCs on the immunogenicity of skin and skin-containing VCA grafts, using mouse models of skin and hind limb transplantation. By post-transplantation day 6, skin grafts demonstrated severe rejections, characterized by predominance of recipient CD4 T cells. In contrast, hind limb grafts showed moderate rejection, primarily infiltrated by CD8 T cells. Notably, the skin component exhibited heightened immunogenicity when compared to the entire VCA, evidenced by increased frequencies of pan (CD11b-CD11c+), mature (CD11b-CD11c+MHCII+) and active (CD11b-CD11c+CD40+) DCs and cDC2 subset (CD11b+CD11c+ MHCII+) in the lymphoid tissues and the blood of skin transplant recipients. While donor depletion of cDC and APC reduced frequencies, maturation and activation of DCs in all analyzed tissues of skin transplant recipients, reduction in DC activities was only observed in the spleen of hind limb recipients. Donor cDC and APC depletion did not impact all lymphocyte compartments but significantly affected CD8 T cells and activated CD4 T in lymph nodes of skin recipients. Moreover, both donor APC and cDC depletion attenuated the Th17 immune response, evident by significantly reduced Th17 (CD4+IL-17+) cells in the spleen of skin recipients and reduced levels of IL-17E and lymphotoxin-α in the serum samples of both skin and hind limb recipients. In conclusion, our findings underscore the highly immunogenic nature of skin component in VCA. The depletion of donor APCs and cDCs mitigates the immunogenicity of skin grafts while exerting minimal impact on VCA.

Significance of melanin distribution in the epidermis for the protective effect against UV light.

Melanin, the most abundant skin chromophore, is produced by melanocytes and is one of the key components responsible for mediating the skin's response to ultraviolet radiation (UVR). Because of its antioxidant, radical scavenging, and broadband UV absorbing properties, melanin reduces the penetration of UVR into the nuclei of keratinocytes. Despite its long-established photoprotective role, there is evidence that melanin may also induce oxidative DNA damage in keratinocytes after UV exposure and therefore be involved in the development of melanoma. The present work aimed at evaluating the dependence of UV-induced DNA damage on melanin content and distribution, using reconstructed human epidermis (RHE) models. Tanned and light RHE were irradiated with a 233 nm UV-C LED source at 60 mJ/cm2 and a UV lamp at 3 mJ/cm2. Higher UV-mediated free radicals and DNA damage were detected in tanned RHE with significantly higher melanin content than in light RHE. The melanin distribution in the individual models can explain the lack of photoprotection. Fluorescence lifetime-based analysis and Fontana-Masson staining revealed a non-homogeneous distribution and absence of perinuclear melanin in the tanned RHE compared to the in vivo situation in humans. Extracellularly dispersed epidermal melanin interferes with photoprotection of the keratinocytes.

Moderate LMWH Anticoagulation Improves Success Rate of Hind Limb Allotransplantation in Mice.

Background: The mouse hind limb model represents a powerful research tool in vascularized composite tissue allotransplantation, but its applicability is limited due to poor graft survival (62%-83%). Vascular thrombosis and massive hemorrhage are the major causes for these drop-outs. We hypothesize that because of better anticoagulation effect and lower risk of thrombocytopenia, application of low molecular weight heparin (LMWH) will minimize vascular complications and enhance graft and animal survival. Methods: Fifty allogeneic hind limb transplantations were performed (C57BL/6 to DBA/2 mice) using five different anticoagulation protocols. Bleeding and thromboembolic events were recorded macroscopically by postoperative hemorrhage and livid discoloration of the graft, respectively. Graft perfusion and survival were monitored daily by capillary-refill-time of graft toes within 2-3 seconds. Vascular congestion and tissue necrosis were examined by histological evaluation of hematoxylin-eosin-stained tissue sections. Results: All transplantations were technically successful. Increase in thromboembolic events and a concomitant decrease in bleeding events were observed with the decreasing concentration of heparin in the perfusion solution. Although treatment of donor and recipient with low dose of LMWH could not reduce thromboembolic events, moderate dose effectively reduced these events. Compared with the poor outcome of graft perfusion with heparin alone, additional treatment of donor and recipient with low dose of LMWH improved graft and animal survival by 18%. Interestingly, animals treated with moderate dose of LMWH demonstrated 100% graft and animal survival. Conclusions: Treatment of donor and recipient mice with a moderate dose of LMWH prevents vascular complications and improves the outcome of murine hind limb transplants.

Erythematous capillary-lymphatic malformations mimicking blood vascular anomalies.

Superficial erythematous cutaneous vascular malformations are assumed to be blood vascular in origin, but cutaneous lymphatic malformations can contain blood and appear red. Management may be different and so an accurate diagnosis is important. Cutaneous malformations were investigated through 2D histology and 3D whole-mount histology. Two lesions were clinically considered as port-wine birthmarks and another 3 lesions as erythematous telangiectasias. The aims were (i) to demonstrate that cutaneous erythematous malformations including telangiectasia can represent a lymphatic phenotype, (ii) to determine if lesions represent expanded but otherwise normal or malformed lymphatics, and (iii) to determine if the presence of erythrocytes explained the red color. Microscopy revealed all lesions as lymphatic structures. Port-wine birthmarks proved to be cystic lesions, with nonuniform lymphatic marker expression and a disconnected lymphatic network suggesting a lymphatic malformation. Erythematous telangiectasias represented expanded but nonmalformed lymphatics. Blood within lymphatics appeared to explain the color. Blood-lymphatic shunts could be detected in the erythematous telangiectasia. In conclusion, erythematous cutaneous capillary lesions may be lymphatic in origin but clinically indistinguishable from blood vascular malformations. Biopsy is advised for correct phenotyping and management. Erythrocytes are the likely explanation for color accessing lymphatics through lympho-venous shunts.

Far-UVC- and UVB-induced DNA damage depending on skin type.

Far-UVC radiation sources of wavelengths 222 nm and 233 nm represent an interesting potential alternative for the antiseptic treatment of the skin due to their high skin compatibility. Nevertheless, no studies on far-UVC-induced DNA damage in different skin types have been published to date, which this study aims for. After irradiating the skin with far-UVC of the wavelengths 222 and 233 nm as well as broadband UVB, the tissue was screened for cyclobutane pyrimidine dimer-positive (CPD+ ) cells using immunohistochemistry. The epidermal DNA damage was lower in dark skin types than in fair skin types after irradiation at 233 nm. Contrary to this, irradiation at 222 nm caused no skin type-dependent differences, which can be attributed to the decreased penetration depth of radiation. UVB showed the relatively strongest differences between light and dark skin types when using a suberythemal dose of 3 mJ/cm2 . As melanin is known for its photoprotective effect, we evaluated the ratio of melanin content in the stratum basale and stratum granulosum in samples of different skin types using two-photon excited fluorescence lifetime imaging (TPE-FLIM) finding a higher ratio up to skin type IV-V. As far-UVC is known to penetrate only into the upper layers of the viable skin, the aforementioned melanin ratio could explain the less pronounced differences between skin types after irradiation with far-UVC compared to UVB.

Three-Dimensional Histological Characterization of the Placental Vasculature Using Light Sheet Microscopy.

The placenta is the first embryonic organ, representing the connection between the embryo and the mother, and is therefore necessary for the embryo's growth and survival. To meet the ever-growing need for nutrient and gas exchange, the maternal spiral arteries undergo extensive remodeling, thus increasing the uteroplacental blood flow by 16-fold. However, the insufficient remodeling of the spiral arteries can lead to severe pregnancy-associated disorders, including but not limited to pre-eclampsia. Insufficient endovascular trophoblast invasion plays a key role in the manifestation of pre-eclampsia; however, the underlying processes are complex and still unknown. Classical histopathology is based on two-dimensional section microscopy, which lacks a volumetric representation of the vascular remodeling process. To further characterize the uteroplacental vascularization, a detailed, non-destructive, and subcellular visualization is beneficial. In this study, we use light sheet microscopy for optical sectioning, thus establishing a method to obtain a three-dimensional visualization of the vascular system in the placenta. By introducing a volumetric visualization method of the placenta, we could establish a powerful tool to deeply investigate the heterogeneity of the spiral arteries during the remodeling process, evaluate the state-of-the-art treatment options, effects on vascularization, and, ultimately, reveal new insights into the underlying pathology of pre-eclampsia.

Over 30 Years of Pediatric Liver Transplantation at the Charité-Universitätsmedizin Berlin.

BACKGROUND: Pediatric liver transplantation (LT) is the treatment of choice for children with end-stage liver disease and in certain cases of hepatic malignancies. Due to low case numbers, a technically demanding procedure, the need for highly specialized perioperative intensive care, and immunological, as well as infectious, challenges, the highest level of interdisciplinary cooperation is required. The aim of our study was to analyze short- and long-term outcomes of pediatric LT in our center. METHODS: We conducted a retrospective single-center analysis of all liver transplantations in pediatric patients (≤16 years) performed at the Department of Surgery, Charité - Universitätsmedizin Berlin between 1991 and 2021. Three historic cohorts (1991-2004, 2005-2014 and 2015-2021) were defined. Graft- and patient survival, as well as perioperative parameters were analyzed. The study was approved by the institutional ethics board. RESULTS: Over the course of the 30-year study period, 212 pediatric LTs were performed at our center. The median patient age was 2 years (IQR 11 years). Gender was equally distributed (52% female patients). The main indications for liver transplantation were biliary atresia (34%), acute hepatic necrosis (27%) and metabolic diseases (13%). The rate of living donor LT was 25%. The median cold ischemia time for donation after brain death (DBD) LT was 9 h and 33 min (IQR 3 h and 46 min). The overall donor age was 15 years for DBD donors and 32 years for living donors. Overall, respective 1, 5, 10 and 30-year patient and graft survivals were 86%, 82%, 78% and 65%, and 78%, 74%, 69% and 55%. One-year patient survival was 85%, 84% and 93% in the first, second and third cohort, respectively (p = 0.14). The overall re-transplantation rate was 12% (n = 26), with 5 patients (2%) requiring re-transplantation within the first 30 days. CONCLUSION: The excellent long-term survival over 30 years showcases the effectiveness of liver transplantation in pediatric patients. Despite a decrease in DBD organ donation, patient survival improved, attributed, besides refinements in surgical technique, mainly to improved interdisciplinary collaboration and management of perioperative complications.

Application of 233 nm far-UVC LEDs for eradication of MRSA and MSSA and risk assessment on skin models.

A newly developed UVC LED source with an emission wavelength of 233 nm was proved on bactericidal efficacy and skin tolerability. The bactericidal efficacy was qualitatively analysed using blood agar test. Subsequently, quantitative analyses were performed on germ carrier tests using the MRSA strain DSM11822, the MSSA strain DSM799, S. epidermidis DSM1798 with various soil loads. Additionally, the compatibility of the germicidal radiation doses on excised human skin and reconstructed human epidermis was proved. Cell viability, DNA damage and production of radicals were assessed in comparison to typical UVC radiation from discharge lamps (222 nm, 254 nm) and UVB (280-380 nm) radiation for clinical assessment. At a dose of 40 mJ/cm2, the 233 nm light source reduced the viable microorganisms by a log10 reduction (LR) of 5 log10 levels if no soil load was present. Mucin and protein containing soil loads diminished the effect to an LR of 1.5-3.3. A salt solution representing artificial sweat (pH 8.4) had only minor effects on the reduction. The viability of the skin models was not reduced and the DNA damage was far below the damage evoked by 0.1 UVB minimal erythema dose, which can be regarded as safe. Furthermore, the induced damage vanished after 24 h. Irradiation on four consecutive days also did not evoke DNA damage. The radical formation was far lower than 20 min outdoor visible light would cause, which is classified as low radical load and can be compensated by the antioxidant defence system.

Hepatic artery reconstruction using an operating microscope in pediatric liver transplantation-Is it worth the effort?

INTRODUCTION: In pediatric liver transplantation (pLT), hepatic artery thrombosis (HAT) is associated with inferior transplant outcome. Hepatic artery reconstruction (HAR) using an operating microscope (OM) is considered to reduce the incidence of HAT. METHODS: HAR using an OM was compared to a historic cohort using surgical loupes (SL) in pLT performed between 2009 and 2020. Primary endpoint was the occurrence of HAT. Secondary endpoints were 1-year patient and graft survival determined by Kaplan-Meier analysis and complications. Multivariate analysis was used to identify independent risk factors for HAT and adverse events. RESULTS: A total of 79 pLTs were performed [30 (38.0%) living donations; 49 (62.0%) postmortem donations] divided into 23 (29.1%) segment 2/3, 32 (40.5%) left lobe, 4 (5.1%) extended right lobe, and 20 (25.3%) full-size grafts. One-year patient and graft survival were both 95.2% in the OM group versus 86.2% and 77.8% in the SL group (p = .276 and p = .077). HAT rate was 0% in the OM group versus 24.1% in the SL group (p = .013). One-year patient and graft survival were 64.3% and 35.7% in patient with HAT, compared to 93.9% and 92.8% in patients with no HAT (both p < .001). Multivariate analysis revealed HAR with SL (p = .022) and deceased donor liver transplantation (DDLT) (p = .014) as independent risk factors for HAT. The occurrence of HAT was independently associated with the need for retransplantation (p < .001) and biliary leakage (p = .045). CONCLUSION: In pLT, the use of an OM is significantly associated to reduce HAT rate, biliary complications, and graft loss and outweighs the disadvantages of delayed arterial perfusion and prolonged warm ischemia time (WIT).

Risk Factor Analysis for Flap and Donor Site Related Complications in 1274 DIEP Flaps - Retrospective Single Center Study.

Background: Breast cancer is the most common cancer affecting women worldwide. In Germany, in almost 70% of cases, women require a complete mastectomy and wish for breast reconstruction which is especially difficult when the breast was previously irradiated. The DIEP flap is then the gold standard for autologous breast reconstruction and shows an overall low complication rate. This study aims to underline the safety of the procedure yet point out potential risk factors for flap edge and fat necrosis in a retrospective series of 1274 DIEP flaps in our center. Patients and Methods: 1274 autologous breast reconstructions with the DIEP flap were performed in 1124 patients between July 2004 and December 2014 in our department. Retrospective risk factor analysis included age, BMI, smoking, chemotherapy and/or radiotherapy and comorbidities. Mean follow-up constituted out of 24 months. Results: Out of 1274 free DIEP flap breast reconstructions, 150 were bilateral reconstructions. In 785 cases the primary indication was previous mastectomy, followed by prior implant-based reconstruction in 265 cases. The total flap loss rate was 0.6%. Patients with a higher BMI and smokers had significantly higher complication rates than the rest of the cohort. Elderly patients ( 65 years), patients with diabetes and ones who had undergone chemo-/ radiotherapy did not present with higher complication rates. Conclusions: The DIEP flap surgery is a well-established method for autologous breast reconstruction with a low complication rate. Yet patient characteristics in terms of risk factors need to be taken into account for result prognosis and satisfactory long-term reconstructive results.

The DIEP Flap as Well-established Method of Choice for Autologous Breast Reconstruction with a Low Complication Rate - Retrospective Single-centre 10-Year Experience.

Background Breast cancer is the most common cancer affecting women in Germany. Despite breast-conserving therapy (BCT) being carried out in almost 70% of cases, a high number of women still require complete mastectomy. Prophylactic mastectomy is also indicated for women with a BRCA 1/2 gene mutation. In addition to implant-based heterologous breast reconstruction, autologous breast reconstruction using a DIEP flap has been found to be beneficial, particularly for patients who had prior radiotherapy. This study aims to show that DIEP flap reconstruction surgery is the method of choice for autologous breast reconstruction with a low rate of complications. Patients and Methods Autologous breast reconstruction using a DIEP flap was performed in 1124 patients between July 2004 and December 2014. Retrospective study criteria included potential risk factors such as age, BMI, smoking, chemotherapy and/or radiotherapy, and comorbidities as well as outcome parameters such as postoperative complications. Outcomes were evaluated with a mean follow-up of 24 months. Results A total of 1124 patients underwent 1274 free DIEP flap breast reconstructions, of which 150 were bilateral reconstructions. The primary indication was previous mastectomy in 785 cases, followed by prior implant-based reconstruction in 265 cases. The total flap loss rate was 0.6%. Postoperative surgical revision for abdominal wall hernia was required in 0.2% of cases. The group with a higher BMI and the group of smokers had significantly higher complication rates. Elderly patients (> 65 years), patients who had undergone chemo-/radiotherapy and patients with diabetes did not have higher complication rates. Conclusion DIEP flap surgery is an excellent option for autologous breast reconstruction, with a low rate of donor site morbidity and low complication rates. DIEP flap surgery carried out in a specialised interdisciplinary breast centre in a standardised clinical setting after prior careful patient selection to take account of risk factors such as high BMI and smoking is a reliable method with a low complication rate and satisfactory long-term reconstruction results.

Outcome after pediatric liver transplantation for staged abdominal wall closure with use of biological mesh-Study with long-term follow-up.

Abdominal wall closure after pediatric liver transplantation (pLT) in infants may be hampered by graft-to-recipient size discrepancy. Herein, we describe the use of a porcine dermal collagen acellular graft (PDCG) as a biological mesh (BM) for abdominal wall closure in pLT recipients. Patients <2 years of age, who underwent pLT from 2011 to 2014, were analyzed, divided into definite abdominal wall closure with and without implantation of a BM. Primary end-point was the occurrence of postoperative abdominal wall infection. Secondary end-points included 1- and 5-year patient and graft survival and the development of abdominal wall hernia. In five out of 21 pLT recipients (23.8%), direct abdominal wall closure was achieved, whereas 16 recipients (76.2%) received a BM. BM removal was necessary in one patient (6.3%) due to abdominal wall infection, whereas no abdominal wall infection occurred in the no-BM group. No significant differences between the two groups were observed for 1- and 5-year patient and graft survival. Two late abdominal wall hernias were observed in the BM group vs none in the no-BM group. Definite abdominal wall closure with a BM after pLT is feasible and safe when direct closure cannot be achieved with comparable postoperative patient and graft survival rates.

Barrier-disrupted skin: Quantitative analysis of tape and cyanoacrylate stripping efficiency by multiphoton tomography.

Numerous studies have employed tape stripping (TS) or cyanoacrylate stripping (CS) to induce skin barrier disruption of the stratum corneum (SC) in human and porcine skin. However, the thickness of the remaining SC and the respective changes of the skin permeability have been rarely quantified. By using high-resolution multiphoton tomography, about 5 µm thick SC was found remaining on human skin after the performance of 30 times TS or 2 times CS. 50 tape strips or 4 times CS removed the entire human SC, but on porcine skin 2-3 µm thick SC was still left. TS can only reach the transition zone between the SC and the stratum granulosum because of the limited adhesion, whereas CS was able to remove viable skin layers. Permeation investigations on porcine skin revealed that the apparent permeability coefficient of the hydrophilic nitroxide spin 2,5,5-Tetramethyl-1-pyrrolidinyloxy-3-carboxylic acid increased 15-, 18-, and 21-fold when the SC amount remaining in the skin was 30%, 16%, and 8%, respectively. It is recommended to use at most 30 times TS or 3 times CS to obtain ex vivo barrier-disrupted skin that mimics diseased skin. The study provides quantitative information for the utility of TS and CS in skin penetration research.

Surgical workflow for fully navigated high sacral amputation in sacral chordoma.

The method of choice for treatment of sacral chordomas is en bloc tumor removal via sacrectomy or sacral amputation in varying degrees depending on the initial tumor extent. Besides local tumor control, the preservation of neurological function is equally important to minimize postoperative bladder and bowel dysfunction. Removal of sacral tumors is complicated by the complex regional anatomy of the pelvis and the surrounding visceral and retroperitoneal structures. We aim to describe the surgical workflow for a fully navigated high sacral amputation facilitated by integration of an intraoperative computed tomography (iCT)-based spinal navigation system. An iCT-based spinal navigation system (AIRO® CT scanner, Brainlab AG, Feldkirchen, Germany) was used to perform intraoperative navigation with an image-guidance system and infrared tracking camera (BrainLab CurveTM, Brainlab AG, Feldkirchen, Germany) in combination with the spinal navigation set by Brainlab (Brainlab AG, Feldkirchen, Germany) to perform a fully navigated high sacral amputation. We demonstrate the successful implementation of iCT-based spinal navigation during high sacral amputation and the key advantages of this technique throughout the surgery. iCT-based spinal navigation is a useful complementing technique for en bloc high sacral amputations that renders the surgery safer and more accurate.

Quantification and characterization of radical production in human, animal and 3D skin models during sun irradiation measured by EPR spectroscopy.

Sun radiation is indispensable to our health, however, a long term and high exposure could lead to erythema, premature skin aging and promotion of skin tumors. An underlying pathomechanism is the formation of free radicals. First, reactive oxygen species (*OH, *O2-) and then, secondary lipid oxygen species (C centered radicals, CCR) are formed. A high amount of free radicals results in oxidative stress with subsequent cell damage. In dermatological research different skin models are used, however, comparative data about the cutaneous radical formation are missing. In this study, the radical formation in porcine-, (SKH-1) murine-, human- ex vivo skin and reconstructed human skin (RHS) were investigated during simulated sun irradiation (305-2200 nm), with X-band EPR spectroscopy. The amount of radical formation was investigated with the spin probe PCA exposed to a moderate sun dose below one minimal erythema dose (MED, ~25 mJ/cm2 UVB) in all skin models. Furthermore, the *OH and *CCR radical concentrations were measured with the spin trap DMPO within 0-4 MED (porcine-, human skin and RHS). The highest amount of radicals was found in RHS followed by murine and porcine, and the lowest amount in human ex vivo skin. In all skin models, more *OH than CCR radicals were found at 0-4 MED. Additionally, this work addresses the limitations in the characterization with the spin trap DMPO. The measurements have shown that the most comparable skin model to in vivo human skin could differ depending on the focus of the investigation. If the amount of radial production is regarded, RHS seems to be in a similar range like in vivo human skin. If the investigation is focused on the radical type, porcine skin is most comparable to ex vivo human skin, at an irradiation dose not exceeding 1 MED. Here, no comparison to in vivo human skin is possible.

CNS myeloid cells critically regulate heat hyperalgesia.

Activation of non-neuronal microglia is thought to play a causal role in spinal processing of neuropathic pain. To specifically investigate microglia-mediated effects in a model of neuropathic pain and overcome the methodological limitations of previous approaches exploring microglia function upon nerve injury, we selectively ablated resident microglia by intracerebroventricular ganciclovir infusion into male CD11b-HSVTK-transgenic mice, which was followed by a rapid, complete, and persistent (23 weeks) repopulation of the CNS by peripheral myeloid cells. In repopulated mice that underwent sciatic nerve injury, we observed a normal response to mechanical stimuli, but an absence of thermal hypersensitivity ipsilateral to the injured nerve. Furthermore, we found that neuronal expression of calcitonin gene-related peptide (CGRP), which is a marker of neurons essential for heat responses, was diminished in the dorsal horn of the spinal cord in repopulated mice. These findings identify distinct mechanisms for heat and mechanical hypersensitivity and highlight a crucial contribution of CNS myeloid cells in the facilitation of noxious heat.

A self-made, low-cost infrared system for evaluating the sciatic functional index in mice.

The sciatic functional index (SFI) is a popular parameter for peripheral nerve evaluation that relies on footprints obtained with ink and paper. Drawbacks include smearing artefacts and a lack of dynamic information during measurement. Modern applications use digitized systems that can deliver results with less analytical effort and fewer mice. However, the systems are expensive (€40,000). This study aimed to evaluate the applicability and precision of a self-made, low-cost infrared system for evaluating SFI in mice. Mice were subjected to unilateral sciatic nerve crush injury (crush group; n = 7) and sham operation (sham group; n = 4). They were evaluated on the day before surgery, the 2(nd), 4(th) and 6(th) days after injury, and then every day up to the 23(rd) day after injury. We compared two SFI evaluation methods, i.e., conventional ink-and-paper SFI (C-SFI) and our infrared system (I-SFI). Our apparatus visualized footprints with totally internally reflected infrared light (950 nm) and a camera that can only detect this wavelength. Additionally we performed an analysis with the ladder beam walking test (LBWT) as a reference test. I-SFI assessment reduced the standard deviation by about 33 percent, from 11.6 to 7.8, and cut the variance around the baseline to 21 percent. The system thus requires fewer measurement repetitions and fewer animals, and cuts the cost of keeping the animals. The apparatus cost €321 to build. Our results show that the process of obtaining the SFI can be made more precise via digitization with a self-made, low-cost infrared system.

DIEAP flap for safe definitive autologous breast reconstruction.

BACKGROUND: Breast cancer is the commonest form of cancer in women affecting almost a quarter of a million patients in the US annually. 30 percent of these patients and patients with genetic mutations undergo removal of the breast, as highlighted in a high profile celebrity patient. Although breast reconstruction with free microvascular transfer of a DIEAP flap from the abdomen is an ideal form of reconstruction, there have been misgivings about the complexity and potential complications. This study was aimed at clearing these misunderstandings and establishing the value of this form of breast reconstruction. METHODS: 1036 DIEAP flap breast reconstructions carried out at the University Hospital, Gent (five year period) and at the Sana Kliniken, Düsseldorf (three year period) were included prospectively. Comorbid factors like chemotherapy, radiotherapy, patient age >65 years, BMI >30 and smoking were recorded. Outcomes were evaluated over a mean follow up of 2 years. RESULTS: Overall complication rate related to the reconstructed breast and donor abdominal area was 6.8 percent. Total flap loss was seen in only 0.8 percent. The mean operating time was less than five hours. Older age, higher BMI, chemotherapy and radiotherapy did not have a significant influence on complication rates, however smoking resulted in significant delay in wound healing in the breast (p = 0.025) and abdominal wounds (p = 0.019). CONCLUSION: The DIEAP flap is an excellent option for breast reconstruction, with a low level of donor site morbidity and complications. It is an autologous reconstruction that provides a stable long term result.

Electrical Nerve Stimulation Enhances Perilesional Branching after Nerve Grafting but Fails to Increase Regeneration Speed in a Murine Model.

Background Electrical stimulation immediately following nerve lesion helps regenerating axons cross the subsequently grafted nerve repair site. However, the results and the mechanisms remain open to debate. Some findings show that stimulation after crush injury increases axonal crossing of the repair site without affecting regeneration speed. Others show that stimulation after transection and fibrin glue repair doubles regeneration distance. Methods Using a sciatic-nerve-transection-graft in vivo model, we investigated the morphological behavior of regenerating axons around the repair site after unilateral nerve stimulation (20 Hz, 1 hour). With mice expressing axonal fluorescent proteins (thy1-YFP), we were able to calculate the following at 5 and 7 days: percentage of regenerating axons and arborizing axons, branches per axon, and regeneration distance and speed. Results Brief stimulation significantly increases the percentage of regenerating axons (5 days: 35.5 vs. 27.3% nonstimulated, p < 0.05; 7 days: 43.3 vs. 33.9% nonstimulated, p < 0.05), mainly by increasing arborizing axons (5 days: 49.3 [4.4] vs. 33.9 [4.1]% [p < 0.001]; 7 days: 42.2 [5.6] vs. 33.2 [3.1]% [p < 0.001]). Neither branches per arborizing axon nor regeneration speed were affected. Conclusion Our morphological data analysis revealed that electrical stimulation in this model increases axonal crossing of the repair site and promotes homogeneous perilesional branching, but does not affect regeneration speed.

Fibrin glue repair leads to enhanced axonal elongation during early peripheral nerve regeneration in an in vivo mouse model.

Microsurgical suturing is the gold standard of nerve coaptation. Although literature on the usefulness of fibrin glue as an alternative is becoming increasingly available, it remains contradictory. Furthermore, no data exist on how both repair methods might influence the morphological aspects (arborization; branching) of early peripheral nerve regeneration. We used the sciatic nerve transplantation model in thy-1 yellow fluorescent protein mice (YFP; n = 10). Pieces of nerve (1cm) were grafted from YFP-negative mice (n = 10) into those expressing YFP. We performed microsuture coaptations on one side and used fibrin glue for repair on the contralateral side. Seven days after grafting, the regeneration distance, the percentage of regenerating and arborizing axons, the number of branches per axon, the coaptation failure rate, the gap size at the repair site and the time needed for surgical repair were all investigated. Fibrin glue repair resulted in regenerating axons travelling further into the distal nerve. It also increased the percentage of arborizing axons. No coaptation failure was detected. Gap sizes were comparable in both groups. Fibrin glue significantly reduced surgical repair time. The increase in regeneration distance, even after the short period of time, is in line with the results of others that showed faster axonal regeneration after fibrin glue repair. The increase in arborizing axons could be another explanation for better functional and electrophysiological results after fibrin glue repair. Fibrin glue nerve coaptation seems to be a promising alternative to microsuture repair.