Face Transplant: Indications, Outcomes, and Ethical Issues-Where Do We Stand?

Tacrolimus-loaded Drug Delivery Systems in Vascularized Composite Allotransplantation: Lessons and Opportunities for Local Immunosuppression

Long-term systemic immunosuppression is needed for vascularized composite allotransplantation (VCA). The high rate of acute rejection episodes in the first posttransplant year, the development of chronic rejection, and the adverse effects that come along with this treatment, currently prevent a wider clinical application of VCA. Opportunistic infections and metabolic disturbances are among the most observed side effects in VCA recipients. To overcome these challenges, local immunosuppression using biomaterial-based drug delivery systems (DDS) have been developed. The aim of these systems is to provide high local concentrations of immunosuppressive drugs while reducing their systemic load. This review provides a summary of recently investigated local DDS with different mechanisms of action such as on-demand, ultrasound-sensitive, or continuous drug delivery. In preclinical models, ranging from rodent to porcine and nonhuman primate models, this approach has been shown to reduce systemic tacrolimus (TAC) load and adverse effects, while prolonging graft survival. Localized immunosuppression using biomaterial-based DDS represents an encouraging approach to enhance graft survival and reduce toxic side effects of immunosuppressive drugs in VCA patients. Preclinical models using TAC-releasing DDS have demonstrated high local immunosuppressive effects with a low systemic burden. However, to reduce acute rejection events in translational animal models or in the clinical reality, the use of additional low-dose systemic TAC treatment may be envisaged. Patients may benefit through efficient graft immunosuppression and survival with negligible systemic adverse effects, resulting in better compliance and quality of life.

HLA Awareness in tissue decellularization: A paradigm shift for enhanced biocompatibility, studied on the model of the human fascia lata graft

Last twenties, tissue engineering has rapidly advanced to address the shortage of organ donors. Decellularization techniques have been developed to mitigate immune rejection and alloresponse in transplantation. However, a clear definition of effective decellularization remains elusive. This study compares various decellularization protocols using the human fascia lata model. Morphological, structural and cytotoxicity/viability analyses indicated that all the five tested protocols were equivalent and met Crapo's criteria for successful decellularization. Interestingly, only the in vivo immunization test on rats revealed differences. Only one protocol exhibited Human Leucocyte Antigen (HLA) content below 1% residual threshold, the only criterion preventing rat immunization with an absence of rat anti-human IgG switch after one month (N=4 donors for each of the 7 groups, added by negative and positive controls, n=28). By respecting a refined set of criteria, i.e. lack of visible nuclear material, <50ng DNA/mg dry weight of extracellular matrix, and <1% residual HLA content, the potential for adverse host reactions can be drastically reduced. In conclusion, this study emphasizes the importance of considering not only nuclear components but also major histocompatibility complex in decellularization protocols and proposes new guidelines to promote safer clinical development and use of bioengineered scaffolds.

What About the Rheological Properties of PRP/Microfat Mixtures in Fat Grafting Procedure?

We reviewed the article "What About the Rheological Properties of PRP/Microfat Mixtures in Fat Grafting Procedure?" and found it highly intriguing. Fat grafting is widely used in plastic surgery, but the issue of inconsistent fat resorption poses a challenge. Platelet-rich plasma (PRP) has been incorporated to enhance fat revascularization, yet the ideal fat-to-PRP ratio remains undetermined. This study focused on analyzing the rheological properties of microfat combined with different proportions of PRP. The preparation protocol for PRP lacks standardization, and the absence of specific platelet and leukocyte information raises concerns. Further analysis is needed to establish reliable conclusions on PRP applications. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The Impact of Duration and Force of Centrifugation on Platelet Content and Mass in the Preparation of Platelet-Rich Plasma

Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Transcriptome profiling of immune rejection mechanisms in a porcine vascularized composite allotransplantation model

Background

Vascularized composite allotransplantation (VCA) offers the potential for a biological, functional reconstruction in individuals with limb loss or facial disfigurement. Yet, it faces substantial challenges due to heightened immune rejection rates compared to solid organ transplants. A deep understanding of the genetic and immunological drivers of VCA rejection is essential to improve VCA outcomes.

Methods

Heterotopic porcine hindlimb VCA models were established and followed until reaching the endpoint. Skin and muscle samples were obtained from VCA transplant recipient pigs for histological assessments and RNA sequencing analysis. The rejection groups included recipients with moderate pathological rejection, treated locally with tacrolimus encapsulated in triglycerol-monostearate gel (TGMS-TAC), as well as recipients with severe end-stage rejection presenting evident necrosis. Healthy donor tissue served as controls. Bioinformatics analysis, immunofluorescence, and electron microscopy were utilized to examine gene expression patterns and the expression of immune response markers.

Results

Our comprehensive analyses encompassed differentially expressed genes, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes pathways, spanning various composite tissues including skin and muscle, in comparison to the healthy control group. The analysis revealed a consistency and reproducibility in alignment with the pathological rejection grading. Genes and pathways associated with innate immunity, notably pattern recognition receptors (PRRs), damage-associated molecular patterns (DAMPs), and antigen processing and presentation pathways, exhibited upregulation in the VCA rejection groups compared to the healthy controls. Our investigation identified significant shifts in gene expression related to cytokines, chemokines, complement pathways, and diverse immune cell types, with CD8 T cells and macrophages notably enriched in the VCA rejection tissues. Mechanisms of cell death, such as apoptosis, necroptosis and ferroptosis were observed and coexisted in rejected tissues.

Conclusion

Our study provides insights into the genetic profile of tissue rejection in the porcine VCA model. We comprehensively analyze the molecular landscape of immune rejection mechanisms, from innate immunity activation to critical stages such as antigen recognition, cytotoxic rejection, and cell death. This research advances our understanding of graft rejection mechanisms and offers potential for improving diagnostic and therapeutic strategies to enhance the long-term success of VCA.

Adverse Events Associated with Hyaluronic Acid Filler Injection for Non-Surgical Facial Aesthetics: A Systematic Review of High Level of Evidence Studies

The article titled "Adverse Events Associated with Hyaluronic Acid Filler Injection for Non-surgical Facial Aesthetics: A Systematic Review of High Level of Evidence Studies" by Kyriazidis et al.in Aesthetic Plastic Surgery presents a systematic review focused on categorizing complications linked to hyaluronic acid (HA) dermal fillers. However, concerns arise about the methodologies employed in the reviewed studies. Precise knowledge of the active substance's properties is vital for treatment standardization. Gaining a comprehensive understanding of the key characteristics of the employed HA is of paramount importance to ascertain whether an association exists between these properties and the risk of complications. Understanding the rheological properties of HA, including viscosity, elasticity, and cohesiveness, is crucial for optimal facial filler selection. Acknowledging the authors' contributions, further analysis should encompass these factors.Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Incorporating Trauma-informed Approaches to Care in Vascularized Composite Allotransplantation

Since 1998, vascularized composite allotransplantation (VCA) has been a growing area of research in the field of reconstructive surgery. Although conditions treated with VCA often result from a traumatic injury, there has been limited emphasis on incorporating trauma-informed care (TIC) models in VCA. Considering the importance of psychosocial well-being in VCA candidates and recipients, applying best practices in TIC to the face, upper extremity, and penile transplantation may be critical in minimizing retraumatization throughout the perioperative process. There are six main principles of TIC: safety; trustworthiness and transparency; peer support; collaboration and mutuality; empowerment and choice; and cultural, historical, and gender issues, which may be further incorporated in care for VCA patients. Evaluating for PTSD and incorporating TIC may have substantial benefit to postoperative outcomes.

The Use of Hyaluronic Acid in Non-surgical Rhinoplasty: A Systematic Review of Complications, Clinical, and Patient-Reported Outcomes

We reviewed the article titled "The Use of Hyaluronic Acid in Non-surgical Rhinoplasty: A Systematic Review of Complications, Clinical, and Patient-Reported Outcomes" authored by Mortada et al. in Aesthetic Plastic Surgery with considerable interest. This study presents a meticulous systematic review of research examining clinical and patient-reported results in hyaluronic acid (HA) non-surgical rhinoplasty. However, we hold specific reservations about the methodologies employed in the studies encompassed within their analysis. Precise comprehension of the properties of the utilized active substance is essential for any treatment, with standardization being a key factor. Understanding the essential characteristics of the administered HAs is pivotal to establish potential connections between these attributes, outcomes, and complications. Of particular importance in the clinical application of tissue volumization via fillers is rheology, the study of material flow and deformation under stress. Gaining insight into HA's rheological properties is imperative when selecting an appropriate dermal filler for nasal applications. Three pivotal HA properties are viscosity, elasticity, and cohesiveness. While appreciating the authors' contributions, further analysis should account for these factors in their investigation.Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Nonsurgical Chin Augmentation Using Hyaluronic Acid: A Systematic Review of Technique, Satisfaction, and Complications

The article titled "Nonsurgical Chin Augmentation Using Hyaluronic Acid: A Systematic Review of Technique, Satisfaction, and Complications" by Ou et al. in Aesthetic Plastic Surgery presents a systematic review focused on categorizing complications associated with hyaluronic acid (HA) dermal fillers. However, concerns arise regarding the methodologies employed in the reviewed studies. It is essential to have precise knowledge of the properties of the active substance for treatment standardization. Gaining a comprehensive understanding of the key characteristics of the HA used is paramount to determine if there is an association between these properties and the risk of complications.Understanding HA's rheological properties, including viscosity, elasticity, and cohesiveness, is crucial for selecting the most suitable facial filler. While we acknowledge the authors' contributions, we strongly believe that further analysis should incorporate these factors.Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

International consensus recommendations on face transplantation: A 2-step Delphi study

Face transplantation is a viable reconstructive approach for severe craniofacial defects. Despite the evolution witnessed in the field, ethical aspects, clinical and psychosocial implications, public perception, and economic sustainability remain the subject of debate and unanswered questions. Furthermore, poor data reporting and sharing, the absence of standardized metrics for outcome evaluation, and the lack of consensus definitions of success and failure have hampered the development of a "transplantation culture" on a global scale. We completed a 2-round online modified Delphi process with 35 international face transplant stakeholders, including surgeons, clinicians, psychologists, psychiatrists, ethicists, policymakers, and researchers, with a representation of 10 of the 19 face transplant teams that had already performed the procedure and 73% of face transplants. Themes addressed included patient assessment and selection, indications, social support networks, clinical framework, surgical considerations, data on patient progress and outcomes, definitions of success and failure, public image and perception, and financial sustainability. The presented recommendations are the product of a shared commitment of face transplant teams to foster the development of face transplantation and are aimed at providing a gold standard of practice and policy.

18 years of face transplantation: Adverse outcomes and challenges

BACKGROUND

Since the first procedure performed in 2005, face transplantation has been debated as viable approach for the treatment of severe craniofacial defects. Despite the benefits provided, the experience in face allotransplantation has brought to light a significant risk of complications, including allograft removal or loss, and mortality. The present study is intended to provide an updated review on complications and major challenges witnessed over 18 years of experience in the field.

METHODS

A systematic review of PubMed, MEDLINE, Cochrane, Google, and Google Scholar databases on face transplantation was conducted according to PRISMA guidelines up to April 2023. Articles providing details on cases of face allograft loss, removal, and patient death were included. Online articles and media reports were assessed to include information not disclosed in peer-reviewed literature. Face transplant centers were contacted to have updated follow-up information on single-face transplant cases.

RESULTS

The search yielded 1006 reports, of which 28 were included. On a total of 48 procedures performed in 46 patients, adverse outcomes were gleaned in 14 cases (29%), including seven allograft losses (14.6%), and the death of ten patients (21.7%). Chronic rejection was the leading cause of allograft loss, with a median time from transplant to irreversible rejection of 90 months (IQR 88.5-102). The main causes of death were infectious complications, followed by malignancies, non-compliance to immunosuppression, and suicide. The median time to death was 48.5 months (IQR 19-122).

CONCLUSIONS

To the best of our knowledge, this is the first study providing a comprehensive review of adverse outcomes in face transplantation. Considering the high rate of major complications, the heterogeneity of cases and single-center approaches, and the absence of published standards of care, the development of a consensus by face transplant teams holds the key to the field's advancement.

Effectiveness and Role of Using Hyaluronic Acid Injections for Gluteal Augmentation: A Comprehensive Systematic Review of Techniques and Outcomes

We have reviewed the article "Effectiveness and Role of Using Hyaluronic Acid Injections for Gluteal Augmentation: A Comprehensive Systematic Review of Techniques and Outcomes" by Mortada et al. in Aesthetic Plastic Surgery with keen interest. This study aims to comprehensively assess the effectiveness and role of hyaluronic acid (HA) in gluteal augmentation. However, we raise concerns about the methodologies employed in the reviewed studies. For effective treatments, understanding the properties of the active substance is essential for standardization. Thoroughly grasping the key characteristics of the employed HAs is vital to identify correlations between these properties, outcomes, and complication risks. Understanding HA's rheological properties, including viscosity, elasticity, and cohesiveness, is pivotal for selecting appropriate dermal fillers for the gluteal region. Another significant aspect of HA use is cohesiveness, arising from internal adhesion based on HA concentration and cross-linking. This cohesiveness resists vertical forces upon implantation, influencing tissue lifting and projection. Gel texture, influenced by Cross-Linking Degree, Particle Size, Molecular Weight, and HA Concentration, also plays a crucial role. While acknowledging authors' contributions, further analysis should consider these factors. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Histomorphometry of the Sural Nerve for Use as a CFNG in Facial Reanimation Procedures

Facial palsy (FP) is a debilitating nerve pathology. Cross Face Nerve Grafting (CFNG) describes a surgical technique that uses nerve grafts to reanimate the paralyzed face. The sural nerve has been shown to be a reliable nerve graft with little donor side morbidity. Therefore, we aimed to investigate the microanatomy of the sural nerve. Biopsies were obtained from 15 FP patients who underwent CFNG using sural nerve grafts. Histological cross-sections were fixated, stained with PPD, and digitized. Histomorphometry and a validated software-based axon quantification were conducted. The median age of the operated patients was 37 years (5-62 years). There was a significant difference in axonal capacity decrease towards the periphery when comparing proximal vs. distal biopsies (p = 0.047), while the side of nerve harvest showed no significant differences in nerve caliber (proximal p = 0.253, distal p = 0.506) and axonal capacity for proximal and distal biopsies (proximal p = 0.414, distal p = 0.922). Age did not correlate with axonal capacity (proximal: R = -0.201, p = 0.603; distal: R = 0.317, p = 0.292). These novel insights into the microanatomy of the sural nerve may help refine CFNG techniques and individualize FP patient treatment plans, ultimately improving overall patient outcomes.

Nanofat in Plastic Reconstructive, Regenerative, and Aesthetic Surgery: A Review of Advancements in Face-Focused Applications

Nanofat is a relatively novel technique in fat grafting that has gained significant interest in the fields of regenerative medicine, aesthetic and translational research. It involves the extraction of autologous fat from a patient, which is then transformed into "nanofat", consisting of small fat particles with a diameter of less than 0.1 mm and containing high concentrations of stem cells and growth factors. This article focuses on the use of nanofat in facial rejuvenation and its potential for lipomodelling. Fat tissue is a "stem cell depot" and nanofat contains many stem cells that can differentiate into various cell types. The Lipogem technology, developed in 2013, enables the isolation of nanofat with an intact perivascular structure, utilizing the high concentration of mesenchymal stromal cells near the pericytes of the adipose vascular system. Nowadays nanofat is used primarily for cosmetic purposes particularly in rejuvenating and improving the appearance of the skin, especially the face. Indeed, it has wide applicability; it can be used to treat fine lines, wrinkles, acne scars, sun-damaged skin, scar repair, and as an alopecia treatment. However, further studies are needed to assess the long-term efficacy and safety of this technique. In conclusion, nanofat is a safe and minimally invasive option for tissue regeneration with considerable therapeutic potential. This study reviews the application and effects of nanofat in regenerative medicine and facial cosmetic surgery.