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1.
J Craniofac Surg ; 2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39283079

RESUMEN

Robotic surgery has emerged as a promising technique for reconstructive procedures, offering potential advantages across various surgical fields. Following initial case reports on the use of the Symani Surgical System (Medical Microinstruments, S.p.A) for microsurgical anastomosis, the authors evaluated its full potential in extremity reconstruction. They conducted a retrospective analysis of patients with soft tissue defects of the upper and lower extremities treated between February 2022 and May 2024. Each patient underwent soft tissue reconstruction with free tissue transfer with microsurgical anastomosis performed using the Symani Surgical System. The study included 7 male patients and 1 female patient, aged between 19 and 71 years (mean age: 50.6 y). The most used recipient vessels were the anterior tibial artery and vein (37.5%). The preferred anastomotic technique was end-to-side in arterial anastomoses (6/8). All arterial anastomoses were performed using the Symani Surgical System. The mean anastomosis time was 33.2±5.8 minutes. One out of 8 patients required surgical revision outside of the anastomosis. The authors' findings suggest that using the Symani Surgical System for microanastomosis in extremity reconstruction is a safe and effective approach, leading to satisfactory outcomes in different anatomic regions. The system allows for the successful execution of various anastomosis techniques, including end-to-end and end-to-side connections, using single interrupted or running sutures, which enhances its versatility in complex reconstructive procedures. The benefits of robotic assistance in terms of precision and ergonomics are promising for the future of reconstructive microsurgery.

2.
Int J Mol Sci ; 25(2)2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38255932

RESUMEN

The treatment of wounds using the body's own resources is a promising approach to support the physiological regenerative process. To advance this concept, we evaluated the effect of nanofat (NF) on wound healing. For this purpose, full-thickness skin defects were created in dorsal skinfold chambers of wild-type mice. These defects were filled with NF generated from the inguinal subcutaneous adipose tissue of green fluorescent protein (GFP)+ donor mice, which was stabilized using platelet-rich plasma (PRP). Empty wounds and wounds solely filled with PRP served as controls. Wound closure, vascularization and formation of granulation tissue were repeatedly analyzed using stereomicroscopy, intravital fluorescence microscopy, histology and immunohistochemistry over an observation period of 14 days. PRP + NF-treated wounds exhibited accelerated vascularization and wound closure when compared to controls. This was primarily due to the fact that the grafted NF contained a substantial fraction of viable GFP+ vascular and lymph vessel fragments, which interconnected with the GFP- vessels of the host tissue. Moreover, the switch from inflammatory M1- to regenerative M2-polarized macrophages was promoted in PRP + NF-treated wounds. These findings indicate that NF markedly accelerates and improves the wound healing process and, thus, represents a promising autologous product for future wound management.


Asunto(s)
Neovascularización Patológica , Cicatrización de Heridas , Animales , Ratones , Piel , Tejido de Granulación , Proteínas Fluorescentes Verdes/genética , Microscopía Fluorescente
3.
Nature ; 526(7573): 443-7, 2015 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-26322584

RESUMEN

Alzheimer disease (AD) is characterized by the accumulation of amyloid plaques, which are predominantly composed of amyloid-ß peptide. Two principal physiological pathways either prevent or promote amyloid-ß generation from its precursor, ß-amyloid precursor protein (APP), in a competitive manner. Although APP processing has been studied in great detail, unknown proteolytic events seem to hinder stoichiometric analyses of APP metabolism in vivo. Here we describe a new physiological APP processing pathway, which generates proteolytic fragments capable of inhibiting neuronal activity within the hippocampus. We identify higher molecular mass carboxy-terminal fragments (CTFs) of APP, termed CTF-η, in addition to the long-known CTF-α and CTF-ß fragments generated by the α- and ß-secretases ADAM10 (a disintegrin and metalloproteinase 10) and BACE1 (ß-site APP cleaving enzyme 1), respectively. CTF-η generation is mediated in part by membrane-bound matrix metalloproteinases such as MT5-MMP, referred to as η-secretase activity. η-Secretase cleavage occurs primarily at amino acids 504-505 of APP695, releasing a truncated ectodomain. After shedding of this ectodomain, CTF-η is further processed by ADAM10 and BACE1 to release long and short Aη peptides (termed Aη-α and Aη-ß). CTFs produced by η-secretase are enriched in dystrophic neurites in an AD mouse model and in human AD brains. Genetic and pharmacological inhibition of BACE1 activity results in robust accumulation of CTF-η and Aη-α. In mice treated with a potent BACE1 inhibitor, hippocampal long-term potentiation was reduced. Notably, when recombinant or synthetic Aη-α was applied on hippocampal slices ex vivo, long-term potentiation was lowered. Furthermore, in vivo single-cell two-photon calcium imaging showed that hippocampal neuronal activity was attenuated by Aη-α. These findings not only demonstrate a major functionally relevant APP processing pathway, but may also indicate potential translational relevance for therapeutic strategies targeting APP processing.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Hipocampo/citología , Metaloproteinasas de la Matriz Asociadas a la Membrana/metabolismo , Neuronas/fisiología , Proteolisis , Proteínas ADAM/metabolismo , Proteína ADAM10 , Enfermedad de Alzheimer/enzimología , Enfermedad de Alzheimer/metabolismo , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Secretasas de la Proteína Precursora del Amiloide/líquido cefalorraquídeo , Secretasas de la Proteína Precursora del Amiloide/deficiencia , Secretasas de la Proteína Precursora del Amiloide/genética , Precursor de Proteína beta-Amiloide/líquido cefalorraquídeo , Precursor de Proteína beta-Amiloide/química , Precursor de Proteína beta-Amiloide/genética , Animales , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/deficiencia , Ácido Aspártico Endopeptidasas/genética , Ácido Aspártico Endopeptidasas/metabolismo , Señalización del Calcio , Modelos Animales de Enfermedad , Femenino , Hipocampo/enzimología , Hipocampo/fisiología , Humanos , Técnicas In Vitro , Potenciación a Largo Plazo , Masculino , Metaloproteinasas de la Matriz Asociadas a la Membrana/deficiencia , Proteínas de la Membrana/metabolismo , Ratones , Peso Molecular , Neuritas/enzimología , Neuritas/metabolismo , Neuronas/enzimología , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Placa Amiloide , Procesamiento Proteico-Postraduccional , Análisis de la Célula Individual
4.
Eur Surg Res ; 59(3-4): 255-264, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30244240

RESUMEN

BACKGROUND: Flap procedures are widely used in clinical reconstructive surgery. Since ische-mia-associated complications, e.g., wound breakdown or tissue necrosis, are still a great challenge in flap surgery, experimental flap models are widely used to study flap physiology and to evaluate treatment strategies to prevent these complications. SUMMARY: Since rodents in general, and mice and rats in particular, are widely used in experimental flap models, we give an overview of the most common flap models in rodents, including the cremaster flap, the osteomyocutaneous flap, the McFarlane flap, the ear flap, and the dorsal skinfold chamber. Key Messages: Rodent flap models in experimental surgery are manifold and have a long history. These models play an important role in training surgical techniques, understanding flap physiology, defining flap anatomy and vascularity, and developing treatment regimens to prevent the necrosis of ischemically challenged tissue. However, it is important to be aware of the advantages and disadvantages of the single flap models concerning the possible time span of the experiment, the degree of difficulty, and the reproducibility and the translation of the results in humans.


Asunto(s)
Colgajos Quirúrgicos , Animales , Ratones , Ratas , Reproducibilidad de los Resultados
5.
J Peripher Nerv Syst ; 20(4): 392-6, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26306813

RESUMEN

Recent data demonstrate that the normal sensibility of the hand seems to be age-dependent with the best values in the third decade and a consecutive deterioration afterwards. However, it is not clear if long-term tactile training might prevent this age-dependent decline. We evaluated sensibility of the hand in 125 surgeons aged between 26 and 75 years who perform microsurgical operations, thereby undergoing regular tactile training. We examined sensibility of the radial digital nerve of the index finger (N3) and the ulnar digital nerve of the small finger (N10) using static and moving two-point discrimination (2PD) tests and compared the results to 154 age-matched individuals without specific long-term tactile training. We found significantly lower static and moving 2PD values for the sixth, seventh, and eighth decade of life in the microsurgery group compared to the control group (p < 0.05). This study demonstrates that long-term tactile training might prevent the known age-dependent decline of the sensibility of the hand.


Asunto(s)
Envejecimiento/fisiología , Competencia Clínica , Mano/inervación , Microcirugia , Práctica Psicológica , Tacto/fisiología , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Umbral Sensorial/fisiología
6.
Case Reports Plast Surg Hand Surg ; 11(1): 2342332, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38645421

RESUMEN

There is evidence that COVID-19 vaccines may affect the lymphatic system. We report a case of a 40-year-old female who had undergone lymph node transfer for treating primary lymphedema of the legs. Six months later, the patient developed lymphedema of the right arm closely related to mRNA vaccination against COVID-19.

7.
Biomedicines ; 12(3)2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38540303

RESUMEN

Periodic fasting (PF) as a form of dietary restriction has been shown to induce tissue-protective effects against ischemic injury in several different tissues. Accordingly, in this study we analyzed whether a short-term 24 h fast is suitable to prevent necrosis of musculocutaneous flap tissue undergoing acute persistent ischemia. C57BL/6N mice were randomly divided into a PF group (n = 8) and a control group that was given unrestricted access to standard chow (n = 8). The PF animals underwent a 24 h fast immediately before flap elevation and had unrestricted access to food for the rest of the 10 day observation period. Musculocutaneous flaps with a random pattern design were dissected on the animals' backs and mounted into dorsal skinfold chambers. On days 1, 3, 5, 7 and 10 after surgery, nutritive tissue perfusion, angiogenesis and flap necrosis were evaluated using intravital fluorescence microscopy. Thereafter, the flap tissue was excised and fixed for histological and immunohistochemical analyses. The flaps of PF-treated animals exhibited a higher functional capillary density and more newly formed microvessels, resulting in a significantly increased flap survival rate. Moreover, they contained a lower number of myeloperoxidase (MPO)-positive neutrophilic granulocytes and cleaved caspase-3-positive apoptotic cells in the transition zone between vital and necrotic flap tissue. These findings indicate that short-term PF improves tissue survival in ischemically challenged musculocutaneous flaps by maintaining nutritive blood perfusion and dampening ischemia-induced inflammation.

8.
Plast Reconstr Surg Glob Open ; 12(1): e5538, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38260755

RESUMEN

Background: With the increasing demand for aesthetic procedures, autologous fat grafting (AFG) seems to be an attractive option for facial volumization and rejuvenation. The aim of this study was to assess the type and severity of associated complications after facial AFG for aesthetic purposes. Methods: The entire PubMed/Medline and Cochrane databases were screened to identify studies describing complications that occurred after the injection of autologous fat into the face. These complications have been reviewed and analyzed according to their occurrence and severity in the different anatomical regions of the face. Results: Twenty-two articles including 38 patients reported on a total of 58 complications. Thirty-two complications have been classified as severe or permanent, including hemiplegia (n = 11), loss of vision (n = 7), or skin necrosis (n = 3). The other 26 complications were classified as mild or transient, such as lipogranuloma (n = 12) or mycobacterial abscess (n = 2). The majority of complications were reported after injection to the forehead (n = 26) and the temporal region (n = 21). Interestingly, this location seems to be the area at risk because 53% of all severe complications occurred in this anatomical region. Conclusions: AFG to the face is associated with a low incidence of complications, but if they occur, they can be dramatic, particularly in the forehead and temporal region. Nevertheless, AFG can be used to correct age-related changes of the face and volume loss and may represent an alternative to synthetic fillers. Therefore, AFG to the face should be performed by qualified doctors under careful consideration of risks and facial anatomy.

9.
J Robot Surg ; 18(1): 353, 2024 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-39340627

RESUMEN

Achieving precision in microsurgery requires skill, adequate instruments and magnification, as well as extensive training. Dedicated surgical robotic systems have enhanced and expanded the application of (super-)microsurgical techniques by introducing motion scaling and providing improved surgeon ergonomics. In this prospective preclinical trial, we analyzed the learning curve in robotic assisted microsurgery in 13 participants including medical students, residents, and attending physicians. Data on demographics as well as prior experience in surgery, microsurgery, and gaming were collected. In three study sessions, the participants performed nine microsurgical anastomoses each on 2 mm vessel models using the Symani® Surgical System in combination the VITOM 3D exoscope. A senior expert microsurgeon reviewed the de-identified and blinded videos and scored all anastomoses using a modified "Structured Assessment of Microsurgical Skills" (SARMS) score. All participants significantly reduced their time needed per anastomosis and their overall SARMS score, as well as individual scores for motion and speed throughout the trial. We saw a significant correlation of prior years of practice in surgery with the overall mean time and mean SARMS score. In a separate analysis of the three sessions, this influence could no longer be seen in the last session. Furthermore, we found no significant effect of gender, age, hand dominance, or gaming experience on speed and quality of the anastomoses. In this study of 117 robotic assisted anastomoses, a rapid improvement of performance of all participants with different surgical skills levels could be shown, serving as encouraging evidence for further research in the implementation of microsurgical robotic systems.


Asunto(s)
Competencia Clínica , Curva de Aprendizaje , Microcirugia , Procedimientos Quirúrgicos Robotizados , Cirujanos , Humanos , Procedimientos Quirúrgicos Robotizados/educación , Procedimientos Quirúrgicos Robotizados/métodos , Microcirugia/educación , Microcirugia/métodos , Estudios Prospectivos , Masculino , Femenino , Cirujanos/educación , Adulto , Anastomosis Quirúrgica/métodos , Anastomosis Quirúrgica/educación , Internado y Residencia/métodos , Estudiantes de Medicina
10.
J Robot Surg ; 18(1): 164, 2024 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-38581589

RESUMEN

Robotic-assisted microsurgery has gained significant attention in recent years following the introduction of two dedicated microsurgical robotic systems specifically designed for this purpose. These feature higher degrees of movement and motion scaling which are useful tools, especially when performing surgery in areas of the body which are difficult to access. Robotic-assisted microsurgery has been implemented in lymphatic surgery as well as soft tissue reconstructive surgery at our institution over the past 2.5 years. Our study gives an insight into the details and outcomes of the first 100 consecutive (super-) microsurgical anastomoses in peripheral and central lymphatic reconstruction performed with the Symani® Surgical System between 2021 and 2024. In total, 67 patients were treated, receiving robotic-assisted lymphatic reconstruction with lymphatic tissue transfer (LTT) and/or lymphovenous anastomoses (LVA)/lympholymphatic anastomoses (LLA). No anastomosis-associated complications were recorded postoperatively. The majority of patients reported a postoperative improvement of their lymphedema or central lymphatic disorder. In conclusion, we show the successful implementation of the Symani® Surgical System into our clinical practice of lymphatic reconstruction. Although the necessary intraoperative setup and the use of intrinsic motion scaling lead to a slight increase in operating time, the presented study demonstrates the advantages of robotic assistance which becomes particularly evident in lymphatic surgery due to the involved deep surgical sites and the need for supermicrosurgical techniques.


Asunto(s)
Vasos Linfáticos , Linfedema , Procedimientos de Cirugía Plástica , Procedimientos Quirúrgicos Robotizados , Robótica , Humanos , Procedimientos Quirúrgicos Robotizados/métodos , Vasos Linfáticos/cirugía , Anastomosis Quirúrgica/métodos
11.
Front Bioeng Biotechnol ; 12: 1427232, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39011155

RESUMEN

Nanofat is an autologous fat derivative with high regenerative activity, which is usually administered immediately after its generation by mechanical emulsification of adipose tissue. For its potential repeated use over longer time, we herein tested whether cryopreservation of nanofat is feasible. For this purpose, the inguinal fat pads of donor mice were processed to nanofat, which was i) frozen and stored in a freezer at -20°C, ii) shock frozen in liquid nitrogen with subsequent storage at -80°C or iii) gradually frozen and stored at -80°C. After 7 days, the cryopreserved nanofat samples were thawed and immunohistochemically compared with freshly generated nanofat (control). Nanofat frozen and stored at -20°C exhibited the lowest apoptotic rate and highest densities of blood and lymph vessels, which were comparable to those of control. Accordingly, nanofat cryopreserved at -20°C or control nanofat were subsequently fixed with platelet-rich plasma in full-thickness skin defects within dorsal skinfold chambers of recipient mice to assess vascularization, formation of granulation tissue and wound closure by means of stereomicroscopy, intravital fluorescence microscopy, histology and immunohistochemistry over 14 days. These analyses revealed no marked differences between the healing capacity of wounds filled with cryopreserved or control nanofat. Therefore, it can be concluded that cryopreservation of nanofat is simply feasible without affecting its viability and regenerative potential. This may broaden the range of future nanofat applications, which would particularly benefit from repeated administration of this autologous biological product.

12.
Artículo en Inglés | MEDLINE | ID: mdl-38818802

RESUMEN

Autologous fat grafting is a common procedure in plastic, reconstructive, and aesthetic surgery. However, it is frequently associated with an unpredictable resorption rate of the graft depending on the engraftment kinetics. This, in turn, is determined by the interaction of the grafted adipose tissue with the tissue at the recipient site. Accordingly, preconditioning strategies have been developed following the principle of exposing these tissues in the pretransplantation phase to stimuli inducing endogenous protective and regenerative cellular adaptations, such as the upregulation of stress-response genes or the release of cytokines and growth factors. As summarized in the present review, these stimuli include hypoxia, dietary restriction, local mechanical stress, heat, and exposure to fractional carbon dioxide laser. Preclinical studies show that they promote cell viability, adipogenesis, and angiogenesis, while reducing inflammation, fibrosis, and cyst formation, resulting in a higher survival rate and quality of fat grafts in different experimental settings. Hence, preconditioning represents a promising approach to improve the outcome of fat grafting in future clinical practice. For this purpose, it is necessary to establish standardized preconditioning protocols for specific clinical applications that are efficient, safe, and easy to implement into routine procedures.

13.
Front Surg ; 11: 1415010, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38826811

RESUMEN

Introduction: In recent years advances have been made in the microsurgical treatment of congenital or acquired central lymphatic lesions. While acquired lesions can result from any surgery or trauma of the central lymphatic system, congenital lymphatic lesions can have a variety of manifestations, ranging from singular thoracic duct abnormalities to complex multifocal malformations. Both conditions may cause recurrent chylous effusions and downstream lymphatic congestion depending on the anatomical location of the thoracic duct lesion and are associated with an increased mortality due to the permanent loss of protein and fluid. Methods: We present a case series of eleven patients undergoing central lymphatic reconstruction, consisting of one patient with a cervical iatrogenic thoracic duct lesion and eleven patients with different congenital thoracic duct lesions or thrombotic occlusions. Results: Anastomosis of the thoracic duct and a nearby vein was performed on different anatomical levels depending on the underlying central lymphatic pathology. Cervical (n = 4), thoracic (n = 1) or abdominal access (n = 5) was used for central lymphatic reconstruction with promising results. In 9 patients a postoperative benefit with varying degrees of symptom regression was reported. Conclusion: The presented case series illustrates the current rapid advances in the field of central microsurgical reconstruction of lymphatic lesions alongside the relevant literature.

14.
Plast Reconstr Surg Glob Open ; 12(9): e6164, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39286611

RESUMEN

Background: Recent advances in robotic microsurgery have enabled the application of robotic technology in central lymphatic reconstruction. Although the use of microsurgical robots demands careful consideration of associated costs and potentially prolonged operating times, it may offer improved surgical approaches and enhanced accessibility to deeper anatomical structures such as the thoracic duct (TD). Methods: We report on successful reconstruction of the central lymphatic system using the Symani Surgical System in four patients with lesions of the central lymphatic system. The patients were of different age (range: 8 mo-60 y) and had variable conditions, including central conducting lymphatic anomaly and other rare anomalies of the central lymphatic pathways. Results: Depending on the underlying pathology, a cervical access (n = 1) or median laparotomy (n = 3) was chosen to access the TD and perform anastomosis with a nearby vein. In all patients, anastomoses were patent, and chyle leakage decreased postoperatively. From a surgical perspective, the Symani Surgical System improved the precision of the microsurgeon and accessibility to the deep-lying TD. Conclusion: Considering the high morbidity and rarity of pathologies of the central lymphatic system, robotic-assisted microsurgery holds substantial promise in expanding and improving the microsurgical treatment for central lymphatic anomalies.

15.
Nat Commun ; 15(1): 1792, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38413586

RESUMEN

Neutrophils are evolutionarily conserved innate immune cells playing pivotal roles in host defense. Zebrafish models have contributed substantially to our understanding of neutrophil functions but similarities to human neutrophil maturation have not been systematically characterized, which limits their applicability to studying human disease. Here we show, by generating and analysing transgenic zebrafish strains representing distinct neutrophil differentiation stages, a high-resolution transcriptional profile of neutrophil maturation. We link gene expression at each stage to characteristic transcription factors, including C/ebp-ß, which is important for late neutrophil maturation. Cross-species comparison of zebrafish, mouse, and human samples confirms high molecular similarity of immature stages and discriminates zebrafish-specific from pan-species gene signatures. Applying the pan-species neutrophil maturation signature to RNA-sequencing data from human neuroblastoma patients reveals association between metastatic tumor cell infiltration in the bone marrow and an overall increase in mature neutrophils. Our detailed neutrophil maturation atlas thus provides a valuable resource for studying neutrophil function at different stages across species in health and disease.


Asunto(s)
Neutrófilos , Pez Cebra , Animales , Humanos , Ratones , Pez Cebra/genética , Pez Cebra/metabolismo , Animales Modificados Genéticamente , Médula Ósea/metabolismo , Perfilación de la Expresión Génica
16.
Nat Commun ; 15(1): 3745, 2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38702304

RESUMEN

Early childhood tumours arise from transformed embryonic cells, which often carry large copy number alterations (CNA). However, it remains unclear how CNAs contribute to embryonic tumourigenesis due to a lack of suitable models. Here we employ female human embryonic stem cell (hESC) differentiation and single-cell transcriptome and epigenome analysis to assess the effects of chromosome 17q/1q gains, which are prevalent in the embryonal tumour neuroblastoma (NB). We show that CNAs impair the specification of trunk neural crest (NC) cells and their sympathoadrenal derivatives, the putative cells-of-origin of NB. This effect is exacerbated upon overexpression of MYCN, whose amplification co-occurs with CNAs in NB. Moreover, CNAs potentiate the pro-tumourigenic effects of MYCN and mutant NC cells resemble NB cells in tumours. These changes correlate with a stepwise aberration of developmental transcription factor networks. Together, our results sketch a mechanistic framework for the CNA-driven initiation of embryonal tumours.


Asunto(s)
Diferenciación Celular , Variaciones en el Número de Copia de ADN , Proteína Proto-Oncogénica N-Myc , Cresta Neural , Neuroblastoma , Humanos , Neuroblastoma/genética , Neuroblastoma/patología , Cresta Neural/metabolismo , Cresta Neural/patología , Femenino , Proteína Proto-Oncogénica N-Myc/genética , Proteína Proto-Oncogénica N-Myc/metabolismo , Aberraciones Cromosómicas , Células Madre Embrionarias Humanas/metabolismo , Transcriptoma , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica
17.
Nutrients ; 15(18)2023 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-37764859

RESUMEN

Caloric restriction (CR) is a cost-effective and easy-to-perform approach to counteracting surgical stress. The present study therefore evaluates the tissue-protective effects of a 30% CR in musculocutaneous flaps undergoing ischemia. For this purpose, a well-established murine dorsal skinfold chamber model, in combination with random pattern musculocutaneous flaps, was used. C57BL/6N mice were divided at random into a CR group (n = 8) and a control group with unrestricted access to standard chow (n = 8). The CR animals were subjected to a 30% reduction in caloric intake for 10 days before flap elevation. Intravital fluorescence microscopy was carried out on days 1, 3, 5, 7 and 10 after flap elevation to assess the nutritive blood perfusion, angiogenesis and flap necrosis. Subsequently, the flap tissue was harvested for additional histological and immunohistochemical analyses. The CR-treated animals exhibited a significantly higher functional capillary density and more newly formed microvessels within the flap tissue when compared to the controls; this was associated with a significantly higher flap survival rate. Immunohistochemical analyses showed a decreased invasion of myeloperoxidase-positive neutrophilic granulocytes into the flap tissue of the CR-treated mice. Moreover, the detection of cleaved caspase-3 revealed fewer cells undergoing apoptosis in the transition zone between the vital and necrotic tissue in the flaps of the CR-treated mice. These results demonstrate that a CR of 30% effectively prevents flap necrosis by maintaining microperfusion on a capillary level and inhibiting inflammation under ischemic stress. Hence, CR represents a promising novel conditioning strategy for improving the survival of musculocutaneous flaps with random pattern perfusion.


Asunto(s)
Restricción Calórica , Ingestión de Energía , Animales , Ratones , Ratones Endogámicos C57BL , Apoptosis , Necrosis
18.
Plast Reconstr Surg ; 151(5): 1030-1041, 2023 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-36729384

RESUMEN

BACKGROUND: Dietary restriction, such as intermittent fasting (IF), has previously been shown to protect various tissues from ischemia-induced necrosis. Based on this finding, the authors herein evaluated for the first time the tissue-protective effects of IF in musculocutaneous flaps. METHODS: Male C57BL/6N mice were randomly assigned to an IF group ( n = 8) and a control group with unrestricted access to standard diet ( n = 8). IF animals were put on a perioperative feeding schedule with 8 hours of unrestricted access to standard diet per day starting 7 days before flap elevation up to 3 days after surgery. Random pattern musculocutaneous flaps were raised and mounted into a dorsal skinfold chamber. Intravital fluorescence microscopy was performed on days 1, 3, 5, 7, and 10 after surgery for the quantitative assessment of angiogenesis, nutritive blood perfusion, and flap necrosis. After the in vivo observation period, the flaps were harvested for additional histologic and immunohistochemical analyses. RESULTS: The authors found that the IF group exhibited more newly formed microvessels and a higher functional capillary density within the flap tissue when compared with controls. This was associated with a significantly lower rate of tissue necrosis. Immunohistochemical detection of different inflammatory cell subtypes revealed a markedly reduced number of invading myeloperoxidase-positive neutrophilic granulocytes in the musculocutaneous tissue of IF-treated animals. CONCLUSION: Considered together, these findings indicate that IF prevents flap necrosis by maintaining nutritive tissue perfusion and suppressing ischemia-induced inflammation. CLINICAL RELEVANCE STATEMENT: Given the frequent use of flaps in plastic surgery and the high rates of ischemic complications, any new approach to decrease such complications is clinically relevant.


Asunto(s)
Colgajo Miocutáneo , Osteonecrosis , Enfermedades Vasculares , Ratones , Animales , Masculino , Ayuno Intermitente , Microcirculación , Ratones Endogámicos C57BL , Necrosis/etiología , Necrosis/prevención & control , Necrosis/patología , Ratones Endogámicos , Isquemia/etiología , Isquemia/prevención & control , Isquemia/tratamiento farmacológico
19.
Biomedicines ; 11(5)2023 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-37239125

RESUMEN

Microvascular fragments (MVF) derived from enzymatically digested adipose tissue are functional vessel segments that have been shown to increase the survival rate of surgical flaps. However, the underlying mechanisms have not been clarified so far. To achieve this, we raised random-pattern musculocutaneous flaps on the back of wild-type mice and mounted them into dorsal skinfold chambers. The flaps were injected with MVF that were freshly isolated from green fluorescent protein-positive (GFP+) donor mice or saline solution (control). On days 1, 3, 5, 7, and 10 after surgery, intravital fluorescence microscopy was performed for the quantitative assessment of angiogenesis, nutritive blood perfusion, and flap necrosis. Subsequently, the flaps were analyzed by histology and immunohistochemistry. The injection of MVF reduced necrosis of the ischemic flap tissue by ~20%. When compared to controls, MVF-injected flaps also displayed a significantly higher functional capillary density and number of newly formed microvessels in the transition zone, where vital tissue bordered on necrotic tissue. Immunohistochemical analyses revealed a markedly lower number of cleaved caspase-3+ apoptotic cells in the transition zone of MVF-injected flaps and a significantly increased number of CD31+ microvessels in both the flaps' base and transition zone. Up to ~10% of these microvessels were GFP+, proving their origin from injected MVF. These findings demonstrate that MVF reduce flap necrosis by increasing angiogenesis, improving nutritive tissue perfusion, and suppressing apoptosis. Hence, the injection of MVF may represent a promising strategy to reduce ischemia-induced flap necrosis in future clinical practice.

20.
Tissue Eng Part B Rev ; 29(6): 605-622, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37166386

RESUMEN

Adipose tissue resorption after fat grafting is a major drawback in plastic and reconstructive surgery, which is primarily caused by the insufficient blood perfusion of the grafts in the initial phase after transplantation. To overcome this problem, several promising strategies to boost the vascularization and, thus, increase survival rates of fat grafts have been developed in preclinical studies in recent years. These include the angiogenic stimulation of the grafts by growth factors and botulinum neurotoxin A, biologically active gels, and cellular enrichment, as well as the physical and pharmacological stimulation of the transplantation site. To transfer these approaches into future clinical practice, it will be necessary to establish standardized procedures for their safe application in humans. If this succeeds, the surgical outcomes of fat grafting may be markedly improved, resulting in a significant reduction of the physical and psychological stress for the patients.


Asunto(s)
Trasplante de Células Madre Mesenquimatosas , Procedimientos de Cirugía Plástica , Humanos , Tejido Adiposo , Trasplante de Células Madre Mesenquimatosas/métodos , Predicción
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