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250 result(s) for "Langer, Stefan"
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Hyperspectral Imaging (HSI) as a new diagnostic tool in free flap monitoring for soft tissue reconstruction: a proof of concept study
Objectives Free flap surgery is an essential procedure in soft tissue reconstruction. Complications due to vascular compromise often require revision surgery or flap removal. We present hyperspectral imaging (HSI) as a new tool in flap monitoring to improve sensitivity compared to established monitoring tools. Methods We performed a prospective observational cohort study including 22 patients. Flap perfusion was assessed by standard clinical parameters, Doppler ultrasound, and HSI on t0 (0 h), t1 (16–28 h postoperatively), and t2 (39–77 h postoperatively). HSI records light spectra from 500 to 1000 nm and provides information on tissue morphology, composition, and physiology. These parameters contain tissue oxygenation (StO2), near-infrared perfusion- (NIR PI), tissue hemoglobin- (THI), and tissue water index (TWI). Results Total flap loss was seen in n = 4 and partial loss in n = 2 cases. Every patient with StO2 or NIR PI below 40 at t1 had to be revised. No single patient with StO2 or NIR PI above 40 at t1 had to be revised. Significant differences between feasable (StO2 = 49; NIR PI = 45; THI = 16; TWI = 56) and flaps with revision surgery [StO2 = 28 (p < 0.001); NIR PI = 26 (p = 0.002); THI = 56 (p = 0.002); TWI = 47 (p = 0.045)] were present in all HSI parameters at t1 and even more significant at t2 (p < 0.0001). Conclusion HSI provides valuable data in free flap monitoring. The technique seems to be superior to the gold standard of flap monitoring. StO2 and NIR PI deliver the most valuable data and 40 could be used as a future threshold in surgical decision making. Clinical Trial Register This study is registered at the German Clinical Trials Register (DRKS) under the registration number DRKS00020926.
Novel 3D organotypic co-culture model of pleura
Pleural mesothelial cells are the predominant cell type in the pleural cavity, but their role in the pathogenesis of pleural diseases needs to be further elucidated. 3D organotypic models are an encouraging approach for an in vivo understanding of molecular disease development. The aim of the present study was to develop a 3D organotypic model of the pleural mesothelium. Specimens of human pleura parietalis were obtained from patients undergoing surgery at the University Hospital Leipzig, Germany. 3D co-culture model of pleura was established from human pleural mesothelial cells and fibroblasts. The model was compared to human pleura tissue by phase-contrast and light microscopy, immunochemistry and -fluorescence as well as solute permeation test. Histological assessment of the 3D co-culture model displayed the presence of both cell types mimicking the morphology of the human pleura. Vimentin and Cytokeratin, PHD1 showed a similar expression pattern in pleural biopsies and 3D model. Expression of Ki-67 indicates the presence of proliferating cells. Tight junctional marker ZO-1 was found localized at contact zones between mesothelial cells. Each of these markers were expressed in both the 3D co-culture model and human biopsies. Permeability of 3D organotypic co-culture model of pleura was found to be higher for 70 kDa-Dextran and no significant difference was seen in the permeability for small dextran (4 kDa). In summary, the presented 3D organoid of pleura functions as a robust assay for pleural research serving as a precise reproduction of the in vivo morphology and microenvironment.
Novel 3D organotypic co-culture model of pleura
Pleural mesothelial cells are the predominant cell type in the pleural cavity, but their role in the pathogenesis of pleural diseases needs to be further elucidated. 3D organotypic models are an encouraging approach for an in vivo understanding of molecular disease development. The aim of the present study was to develop a 3D organotypic model of the pleural mesothelium. Specimens of human pleura parietalis were obtained from patients undergoing surgery at the University Hospital Leipzig, Germany. 3D co-culture model of pleura was established from human pleural mesothelial cells and fibroblasts. The model was compared to human pleura tissue by phase-contrast and light microscopy, immunochemistry and -fluorescence as well as solute permeation test. Histological assessment of the 3D co-culture model displayed the presence of both cell types mimicking the morphology of the human pleura. Vimentin and Cytokeratin, PHD1 showed a similar expression pattern in pleural biopsies and 3D model. Expression of Ki-67 indicates the presence of proliferating cells. Tight junctional marker ZO-1 was found localized at contact zones between mesothelial cells. Each of these markers were expressed in both the 3D co-culture model and human biopsies. Permeability of 3D organotypic co-culture model of pleura was found to be higher for 70 kDa-Dextran and no significant difference was seen in the permeability for small dextran (4 kDa). In summary, the presented 3D organoid of pleura functions as a robust assay for pleural research serving as a precise reproduction of the in vivo morphology and microenvironment.
Inhibition of adipocyte lipolysis by vaspin impairs thermoregulation in vivo
Altered activity of brown adipose tissue (BAT) contributes to obesity, insulin resistance, and cardiovascular disease. BAT secretes endocrine factors (“batokines”) that regulate thermogenesis. We identify the serpin vaspin as a batokine that modulates adrenergic control of lipolysis and thermogenesis. Adipocyte-specific vaspin overexpression in mice reduces BAT activation and impairs thermoregulation during cold exposure or fasting. Mechanistically, vaspin binds low-density lipoprotein receptors (LRP1, LDLR, vLDLR), inhibiting adrenergic signaling and lipolysis in brown and white adipocytes by modulating phosphodiesterase activity and endocytic lipid uptake. Gene set enrichment analyses in human subcutaneous adipose tissue and in vitro studies confirm vaspin’s anti-lipolytic effects in humans. Overall, vaspin emerges as a regulatory BATokine that fine-tunes BAT thermogenic activity to limit excessive energy expenditure and preserve metabolic balance. Here the authors report that brown adipocyte-derived vaspin reduces heat-producing activity in brown fat by blocking adrenergic signals, helping to regulate energy expenditure and maintain metabolic balance.
Examination of ex-vivo viability of human adipose tissue slice culture
Obesity is associated with significantly higher mortality rates, and excess adipose tissue is involved in respective pathologies. Here we established a human adipose tissue slice cultures (HATSC) model ex vivo. HATSC match the in vivo cell composition of human adipose tissue with, among others, mature adipocytes, mesenchymal stem cells as well as stroma tissue and immune cells. This is a new method, optimized for live imaging, to study adipose tissue and cell-based mechanisms of obesity in particular. HATSC survival was tested by means of conventional and immunofluorescence histological techniques, functional analyses and live imaging. Surgery-derived tissue was cut with a tissue chopper in 500 μm sections and transferred onto membranes building an air-liquid interface. HATSC were cultured in six-well plates filled with Dulbecco's Modified Eagle's Medium (DMEM), insulin, transferrin, and selenium, both with and without serum. After 0, 1, 7 and 14 days in vitro, slices were fixated and analyzed by morphology and Perilipin A for tissue viability. Immunofluorescent staining against IBA1, CD68 and Ki67 was performed to determine macrophage survival and proliferation. These experiments showed preservation of adipose tissue as well as survival and proliferation of monocytes and stroma tissue for at least 14 days in vitro even in the absence of serum. The physiological capabilities of adipocytes were functionally tested by insulin stimulation and measurement of Phospho-Akt on day 7 and 14 in vitro. Viability was further confirmed by live imaging using Calcein-AM (viable cells) and propidium iodide (apoptosis/necrosis). In conclusion, HATSC have been successfully established by preserving the monovacuolar form of adipocytes and surrounding macrophages and connective tissue. This model allows further analysis of mature human adipose tissue biology ex vivo.
Engineering a 3D wounded skin equivalent to study early inflammatory and regenerative responses in vitro
Traditional models for studying wound healing, including 2D cell cultures and animal models, present substantial limitations in mimicking human skin physiology. In this study, we present a three-dimensional wounded skin equivalent (3DWoundSE) composed of human cells as a physiologically relevant platform to investigate wound healing processes. The model builds upon a previously established 3D skin equivalent (3DSE) and incorporates a reproducible partial-thickness dermal punch wound. We characterised the 3DWoundSE using histology, cytotoxicity assays, immunofluorescence staining, and pro-inflammatory cytokine profiling at multiple time points post-wounding. Results revealed hallmark wound responses, including increased lactate dehydrogenase (LDH) and apoptosis-inducing factor (AIF) expression, dynamic Ki-67 proliferation changes, and a pro-inflammatory cytokine response, notably elevated IL-6, IL-8, IL-33 and TNF-α levels. Compared to the intact 3DSE, this 3DWoundSE demonstrated enhanced responsiveness to injury and cytotoxic stimuli, confirming its utility for early wound response assessment. This platform offers a reproducible and ethically sound alternative to animal models, with potential applications in dermatological research, drug development, and therapeutic screening.
Outcomes of tissue reconstruction in distal lower leg fractures: a retrospective cohort study
Background Open and closed fractures can be associated with posttraumatic or postoperative soft tissue defects caused by initial trauma, operative procedures, or infections. This study evaluated the postoperative outcomes in patients with open or closed lower leg fractures, related soft tissue defects, and subsequent flap coverage. Methods We performed a retrospective single-center cohort study in a level 1 trauma center. We analyzed the patients treated from January 2012 through December 2017 and recorded demographics, treatment, and outcome data. The outcome data were measured via patient-reported Foot and Ankle Outcomes Scores (FAOS) and EQ-5D-5L scores. Results We included 22 patients with complicated fractures (11 open and 11 closed) and subsequent soft tissue defects and flap coverages. The mean follow-up time was 41.2 months. Twenty-one patients developed infections, and necrosis at the site of surgery manifested in all closed fractures. Therefore, all patients needed soft tissue reconstructions. Preoperatively, 16 patients underwent arterial examinations via angiography and six underwent ultrasound examinations of the venous system. Ten patients had complications involving the flaps due to ischemia and consequent necrosis. The mean EQ-5D index was 0.62 ± 0.27, and EQ-5D VAS score was 57.7 ± 20.2. The mean FAOS was 60.7 ± 22.2; in particular, quality of life was 32.3 ± 28.8. The rate of returning to work in our patient group was 37.5% after 1 year. Conclusions Distal tibial fractures often require revisions and soft tissue reconstruction. The evaluated patient population had poor outcomes in terms of function, quality of life, and return to work. Furthermore, patients suffering from flap ischemia have worse outcomes than those without flap ischemia.
Quality of Life After Bilateral Risk-Reducing Mastectomy and Simultaneous Reconstruction Using Pre-Pectoral Silicone Implants
Bilateral risk-reducing mastectomy (BRRM) can reduce the risk of developing breast cancer by up to 95% in women with increased exposure. Although survival is increased, mastectomies can adversely affect a patient physically, psychologically, and psychosexually. High health-related quality of life (HRQoL) is often achieved after simultaneous breast reconstruction (BR) following BRRM; however, data on the pre- and postoperative results of HRQoL are lacking. Therefore, we investigated the quality of life, esthetic outcome, and patient well-being after BRRM and simultaneous implant-based BR. Of the 35 patients who underwent skin-sparing or nipple-sparing mastectomy between May 2012 and December 2017 at a university hospital, only 22 completed the evaluation. Baseline data and data on previous operations and operation techniques were retrieved from the patient's charts. BREAST-Q and short form-36 health survey (SF-36) questionnaires were used to evaluate patient satisfaction and HRQoL. SF-36 analysis showed a significantly higher score for pain (p=0.043) in our population than in the general female population. Comparing the pre- and postoperative BREAST-Q results, a significant decrease in the physical well-being of the chest (p=0.0179) and a slight improvement in breast satisfaction were observed (p=0.3266). All patients were well-satisfied with the postoperative outcome, reconstruction, and perioperative surgeon care. Bilateral mastectomy with simultaneous BR using pre-pectoral implants is associated with an HRQoL similar to that of the healthy population. Although bilateral mastectomy may have an immense effect on the psychological, physical, and social aspects, immediate BR preserves the outer appearance and improves self-esteem.
Hyperspectral Imaging Detects Clitoral Vascular Issues in Gender-Affirming Surgery
The aim of this study was to assess the efficacy of hyperspectral imaging (HSI) as an intraoperative perfusion imaging modality during gender affirmation surgery (GAS). The hypothesis posited that HSI could quantify perfusion to the clitoral complex, thereby enabling the prediction of either uneventful wound healing or the occurrence of necrosis. In this non-randomised prospective clinical study, we enrolled 30 patients who underwent GAS in the form of vaginoplasty with the preparation of a clitoral complex from 2020 to 2024 and compared patients’ characteristics as well as HSI data regarding clitoris necrosis. Individuals demonstrating uneventful wound healing pertaining to the clitoral complex were designated as Group A. Patients with complete necrosis of the neo-clitoris were assigned to Group B. Patient characteristics were collected and subsequently a comparative analysis carried out. No significant difference in patient characteristics was observed between the two groups. Necrosis occurred when both StO2 and NIR PI parameters fell below 40%. For the simultaneous occurrence of StO2 and NIR PI of 40% or less, a sensitivity of 92% and specificity of 72% was calculated. Intraoperatively, the onset of necrosis in the clitoral complex can be reliably predicted with the assistance of HSI.
Deep sternal wound infection – latissimus dorsi flap is a reliable option for reconstruction of the thoracic wall
Background At present, data describing patients’ long-term outcomes, quality of life, and survival after deep sternal wound infection are rarely available. The purpose of our study was to evaluate functional outcome and patient well-being after debridement and reconstruction of the sternal defect using a pedicled latissimus dorsi flap following deep sternal wound infection (DSWI). Methods This retrospective analysis reviewed 106 cases of DSWI after open-heart surgery treated between May 1, 2012, and May 31, 2015. The parameters of interest were demographic and medical data, including comorbidity and mortality. Follow-up consisted of physical examination of the patients using a specific shoulder assessment, including strength tests and measurements of pulmonary function. Results The population consisted of 69 (65%) male and 37 (35%) female patients. Their average age at the time of plastic surgery was 69 years (range: 35–85). The 30-day mortality was 20% ( n  = 21); after one-year, mortality was 47% ( n  = 50), and at follow-up, it was 54% ( n  = 58). Heart surgery was elective in 45 cases (42%), urgent in 31 cases (29%) and for emergency reasons in 30 cases (28%). The preoperative European System for Cardiac Operative Risk Evaluation (EuroSCORE) averaged 16.3 (range: 0.88–76.76). On the dynamometer assessment, a value of 181 Newton (N) (±97) could be achieved on the donor side, in contrast to 205 N (±91) on the contralateral side. The inspiratory vital capacity of the lung was reduced to an average of 70.58% (range: 26–118), and the forced expiratory volume in 1 s was decreased to an average of 69.85% (range: 38.2–118). Conclusions Given that only small adverse effects in shoulder function, strength, and pulmonary function were observed, the latissimus dorsi flap appears to be a safe and reliable option for the reconstruction of the sternal region after DSWI.