Activation of T Lymphocytes in Response to Persistent Bacterial Infection: Induction of CD11b and of Toll-Like Receptors on T Cells

T cell activation is invariably associated with virus infections, but activation of T cells is also noted, for example, in patients with persistent bacterial infections with intracellular pathogens or localised bacterial biofilms. The latter is characterised by a destructive inflammatory process. Massive infiltration of leukocytes, predominantly of polymorphonuclear neutrophils (PMNs) and of T lymphocytes, is seen. While PMN influx into sites of bacterial infection is in line with their role as “first-line defence” a role of T cells in bacterial infection has not yet been delineated. We now found evidence for activation and expansion of peripheral blood T cells and an upregulation of Toll-like receptors 1, 2, and 4 on small portions of T cells. T cells recovered from the infected site were terminally differentiated and produced interferon gamma, a cytokine known to enhance functions of phagocytic cells, leading to the conclusion that infiltrated T cells support the local immuner defence

Donor Site Morbidity in Unilateral and Bilateral Transverse Musculocutaneous Gracilis (TMG) Flap Breast Reconstruction: Sensation, Function, Aesthesis and Patient-Reported Outcomes

The transverse musculocutaneous gracilis (TMG) flap has become a popular choice for breast reconstruction. This study aimed to compare the donor site morbidity in unilateral and bilateral procedures. Patients receiving a TMG flap (January 2008–October 2019) were invited to a follow-up and grouped according to unilateral (UL group) or bilateral (BL group) breast reconstruction. Outcome criteria included sensation, function and aesthesis of the thighs. Patient-reported outcomes were surveyed using validated questionnaires. The number and kind of refinement procedures for aesthetic purposes on the donor thighs were evaluated. Thirty-eight patients with 59 TMG flaps were included in the study (UL group: n = 17, BL group: n = 21). Normal to slightly diminished superficial skin sensation was maintained in most of the thigh skin (98.4%). Strength and mobility were without impairment in >80% of the thighs in both groups. Thigh symmetry was achieved in both groups. Symmetrisation procedures were significantly more often performed in the UL group (p = 0.005). The total number of refinement procedures was similar in both groups. Patient-reported outcomes were similar with good appearance of the thighs and scars, excellent function and low pain levels. The TMG flap offers excellent function and sensation on the donor thigh. Thigh symmetry and good patient satisfaction may be achieved in both unilateral and bilateral breast reconstructions

Multidisciplinary team meetings for patients with complex extremity defects: a retrospective analysis of treatment recommendations and prognostic factors for non-implementation

Background!#!This study aimed to assess a multidisciplinary team (MDT) meeting approach for the management of patients with complex extremity defects, analyze treatment recommendations, and evaluate factors influencing non-implementation.!##!Methods!#!All patients introduced to an MDT meeting for complex extremity defects from 2015 to 2017 were included in a retrospective cohort study. Patients' characteristics and defect causes were evaluated. Treatment recommendations (TR) of MDT meetings and subsequent implementation were reviewed (cohort with implementation of TR versus cohort with non-implementation of TR), and factors associated with non-adherence to recommendations were statistically analyzed using logistic regression.!##!Results!#!Fifty-one patients (41 male) with a mean age of 54 years were presented in 27 MDT meetings. Most of the patients (70%) suffered from reconstructive challenging or combined bone- and soft tissue defects, primarily located at the lower extremity (88%). Large skeletal defects, chronic osteomyelitis, and multi-fragmented fractures were present in 65% of cases. Forty-five percent of the patients suffered from peripheral vascular disease, necessitating surgical optimization. Of the 51 MDT decisions, 40 were implemented (78%; (32/40) limb salvage versus 22%; (8/40) limb amputation). Limb salvage was successfully achieved in 91% (29/32) of the cases. Failed limb salvages were due to flap failure (33%; 1/3), recurring periprosthetic joint infections (66%; 2/3) and concomitant reconstructive failure. Patients who underwent limb amputation, as recommended, showed proper stump healing and regained mobility with a prosthesis. Overall the MDT treatment plan was effective in 92.5% (37/40) of the patients, who adhered to the MDT treatment recommendation. In eleven patients (22%; 11/51), the MDT treatment was not implemented. MDT decisions were less likely to be implemented, if amputation was recommended (p = 0.029).!##!Conclusions!#!MDT meetings represent a valid tool to formulate individualized treatment plans, avoiding limb amputation in most patients with severe extremity defects. Recommendation for limb amputation is less likely to be implemented than plans for limb salvage.!##!Trial registration!#!Retrospectively registered

A new porcine vascularized tibial bone allotransplantation model. Anatomy and surgical technique

Introduction: Vascularized bone allotransplantation may provide new options for reconstruction of segmental defects if problems of long-term immune modulation can be solved. The current literature lacks an orthotopic large animal model, limited to bone and without the confounding effects of other tissue types, permitting a multifaceted evaluation before new methods are used clinically. The purpose of this study was to develop a large animal model for vascularized bone allotransplantation. Materials and methods: Eight porcine hind limbs were dissected. Length, diameter, and location of all hindlimb vessels were measured and a single nutrient vessel supplying the tibial diaphysis identified enabling its use as a vascularized bone allotransplant. Four Yucatan minipigs were divided into two pairs with a major swine leukocyte antigen mismatch. A 3.5 cm tibial segment including its nutrient pedicle was raised simultaneously from each pig and transplanted into the matched defect of the other animal. Microarterial anastomosis of the pedicle and 3-drug immunosuppression maintained VCA viability. Bone healing and limb function were followed for 16 weeks. Results: A consistent tibia diaphyseal nutrient artery arose from the caudal tibial artery to enter bone a mean 2.8 mm distal to the tibial tubercle with a pedicle length of 6.6 ± 3.3 mm and diameter of 1.6 ± 0.2 mm. Using this pedicle, we reconstructed a 3.5 cm tibial defect with a vascularized bone allotransplant in four animals. Immediate weightbearing as well as progressive bone healing was demonstrated. Conclusion: We have developed a vascularized tibial bone allotranplantation large-animal model suitable for future bone-only allotranplantation research in mini-pigs

Effects of Surgical Angiogenesis on Segmental Bone Reconstruction With Cryopreserved Massive-Structural Allografts in a Porcine Tibia Model

Cryopreserved bone allografts (CBA) used to reconstruct segmental bone defects provide immediate structural stability, but are vulnerable to infection, non-union and late stress fracture as the majority of the allograft remains largely avascular. We sought to improve the bone vascularity and bone formation of CBAs by surgical angiogenesis with an implanted arteriovenous (AV) bundle, using a porcine tibial defect model. Cryopreserved tibial bone allografts were transplanted in swine leukocyte antigen (SLA) mismatched Yucatan minipigs to reconstruct a 3.5 cm segmental tibial defect. A cranial tibial AV-bundle was placed within its intramedullary canal to induce angiogenesis. The AV bundle was patent in eight pigs and ligated in a control group of eight pigs. At 20 weeks neo-angiogenesis was evaluated by micro-angiography. Bone formation was measured by quantitative histomorphometry and micro-computed tomography. Seven of eight AV-bundles in the revascularized group were patent. One had thrombosed due to allograft displacement. Total vascular volume was higher in the revascularized allografts compared to the ligated group (p = 0.015). Revascularized allografts had increased levels of bone formation on the allograft endosteal surface compared to the ligated control group (p = 0.05). Surgical angiogenesis of porcine tibial CBAs by intramedullary implantation of an AV-bundle creates an enhanced autogenous neoangiogenic circulation and accelerates active bone formation on allograft endosteal surfaces. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1698–1708, 2019

The transverse musculocutaneous gracilis flap for autologous breast reconstruction: focus on donor site morbidity

Purpose!#!The transverse musculocutaneous gracilis (TMG) flap is as a valuable alternative in autologous breast reconstruction. The purpose of this study was to evaluate the donor site morbidity and secondary refinement procedures after TMG flap breast reconstruction.!##!Methods!#!A retrospective study was conducted, including all patients who received TMG flap breast reconstructions, from January 2012 to August 2019. Primary outcomes were surgical site complications of the donor site and secondary refinement procedures carried out for aesthetic or reconstructive purposes for the medial thigh. Secondary outcomes of interest were lipofilling procedures for optimization of the reconstructed breasts.!##!Results!#!Ninety-nine patients received 159 TMG flaps for breast reconstruction. Patients' mean BMI was 23.5 (15.6-32.5) kg/m!##!Conclusion!#!The TMG flap breast reconstruction combines low donor site morbidity with adequate volume for appealing breast results, particularly in slim-to-normal weight patients. However, patients should be informed about the likelihood of secondary refinement procedures on the donor site and the need of lipofilling to optimize the breast shape and volume

Oral doxycycline prevents skin-associated adverse effects induced by injectable collagenase in a rodent model of capsular contracture around silicone implants.

BackgroundThe collagenase of the bacterium Clostridium histolyticum (CCH) is already an established treatment for fibroproliferative diseases like M. Dupuytren and M. Peyronie Although results are comparable to surgical intervention, skin laceration is a severe and relevant side effect. Doxycycline (DOX) recently rose interest as an inhibitor of matrix-metalloproteinases alongside its capabilities of skin accumulation. It therefore might be a potential skin protective agent in the use of CCH.MethodsFor simulation of a fibroproliferative disease adjacent to the skin, we utilized a rodent model of capsular fibrosis involving silicone implants and subsequent fibrotic capsule formation. For in-vitro studies, fibrotic capsules were excised and incubated with 0.9 mg/ml CCH and four different doses of DOX. For in-vivo experiments, animals received 0.0, 0.3 or 0.9 mg/ml CCH injections into the fibrotic capsules with or without prior oral DOX administration. Outcome analysis included histology, immunohistochemistry, gene expression analysis, chemical collagen and DOX concentration measurements as well as μCT imaging.ResultsIn-vitro, DOX showed a dose-dependent inhibition of CCH activity associated with increasing capsule thickness and collagen density and content. In-vivo, oral DOX administration did neither interfere with capsule formation nor in effectiveness of CCH dissolving fibrotic capsule tissue. However, skin thickness and especially collagen density was significantly higher compared to control groups. This led to a reduced rate of clinical skin lacerations after DOX administration.ConclusionDOX inhibits CCH and accumulates in the skin. Thereby, DOX can effectively reduce skin laceration after CCH treatment

Teaching Microsurgical Breast Reconstruction—A Retrospective Cohort Study

Microsurgical breast reconstruction demands the highest level of expertise in both reconstructive and aesthetic plastic surgery. Implementation of such a complex surgical procedure is generally associated with a learning curve defined by higher complication rates at the beginning. The aim of this study was to present an approach for teaching deep inferior epigastric artery perforator (DIEP) and transverse upper gracilis (TUG) flap breast reconstruction, which can diminish complications and provide satisfying outcomes from the beginning. DIEP and TUG flap procedures for breast reconstruction were either performed by a senior surgeon (>200 DIEP/TUG, ”no-training group”), or taught to one of five trainees (>80 breast surgeries; >50 free flaps) in a step-wise approach. The latter were either performed by the senior surgeon, and a trainee was assisting the surgery (“passive training”); by the trainee, and a senior surgeon was supervising (“active training”); or by the trainee without a senior surgeon (“after training”). Surgeries of each group were analyzed regarding OR-time, complications, and refinement procedures. A total of 95 DIEP and 93 TUG flaps were included into this study. Before the first DIEP/TUG flap without supervision, each trainee underwent a mean of 6.8 DIEP and 7.3 TUG training surgeries (p > 0.05). Outcome measures did not reveal any statistically significant differences (passive training/active training/after training/no-training: OR-time (min): DIEP: 331/351/338/304 (p > 0.05); TUG: 229/214/239/217 (p > 0.05); complications (n): DIEP: 6/13/16/11 (p > 0.05); TUG: 6/19/23/11 (p > 0.05); refinement procedures (n): DIEP:71/63/49/44 (p > 0.05); TUG: 65/41/36/56 (p > 0.05)), indicating safe and secure implementation of this step-wise training approach for microsurgical breast reconstruction in both aesthetic and reconstructive measures. Of note, despite being a perforator flap, DIEP flap required no more training than TUG flap, highlighting the importance of flap inset at the recipient site

Effective or Harmful—Evaluation of Locally Applied Antibiotics on Adipose Tissue during Lipofilling to the Breast—An In Vitro Study

Lipofilling is a frequently used and safe procedure for breast reconstruction. One of the most feared complications is soft tissue infection following lipofilling. Because of this, some surgeons propose the practice of rinsing fat grafts with antibiotics. This study investigates the effect of antibiotic rinses on fat grafts in an in vitro model. Adipocytes and stem cells were isolated from fat tissue harvested during 24 lipofilling procedures and incubated with different doses of clindamycin or cefazolin. Cell viability, metabolism, proliferation, and differentiation capacities were analyzed by gross morphology, fluorescence staining, -(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid (MTT-), and Glyceraldehyde 3 Phosphate Dehydrogenase (G3PD)-assay as well as reactive oxygen species (ROS)-assay. Cefazolin and clindamycin led to significant reduction of cell viability of adipocytes. High doses of both antibiotics led to a rupture of adipocytes with visible free lipid droplets. Cell metabolism was significantly decreased after incubation with both antibiotics. There was a significant increase in ROS production. Exposure to clindamycin and cefazolin led to morphological changes in stem cells in a dose- and time-dependent manner. Furthermore, differentiation potential was significantly reduced. Antibiotic susceptibility testing, however, showed that low concentrations of antibiotics effectively inhibited bacterial growth in contaminated fat grafts. This study confirms that rinsing fat grafts with clindamycin or cefazolin not only overly prevents infection but also has cytotoxic and metabolic effects on adipocytes. Therefore, based on these results, the routine clinical application in high doses cannot be recommended

Effective or Harmful—Evaluation of Locally Applied Antibiotics on Adipose Tissue during Lipofilling to the Breast—An In Vitro Study

Lipofilling is a frequently used and safe procedure for breast reconstruction. One of the most feared complications is soft tissue infection following lipofilling. Because of this, some surgeons propose the practice of rinsing fat grafts with antibiotics. This study investigates the effect of antibiotic rinses on fat grafts in an in vitro model. Adipocytes and stem cells were isolated from fat tissue harvested during 24 lipofilling procedures and incubated with different doses of clindamycin or cefazolin. Cell viability, metabolism, proliferation, and differentiation capacities were analyzed by gross morphology, fluorescence staining, -(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid (MTT-), and Glyceraldehyde 3 Phosphate Dehydrogenase (G3PD)-assay as well as reactive oxygen species (ROS)-assay. Cefazolin and clindamycin led to significant reduction of cell viability of adipocytes. High doses of both antibiotics led to a rupture of adipocytes with visible free lipid droplets. Cell metabolism was significantly decreased after incubation with both antibiotics. There was a significant increase in ROS production. Exposure to clindamycin and cefazolin led to morphological changes in stem cells in a dose- and time-dependent manner. Furthermore, differentiation potential was significantly reduced. Antibiotic susceptibility testing, however, showed that low concentrations of antibiotics effectively inhibited bacterial growth in contaminated fat grafts. This study confirms that rinsing fat grafts with clindamycin or cefazolin not only overly prevents infection but also has cytotoxic and metabolic effects on adipocytes. Therefore, based on these results, the routine clinical application in high doses cannot be recommended