qMAP enabled microanatomical mapping of human skin aging.

Aging is a major driver of diseases in humans. Identifying features associated with aging is essential for designing robust intervention strategies and discovering novel biomarkers of aging. Extensive studies at both the molecular and organ/whole-body physiological scales have helped determined features associated with aging. However, the lack of meso-scale studies, particularly at the tissue level, limits the ability to translate findings made at molecular scale to impaired tissue functions associated with aging. In this work, we established a tissue image analysis workflow - quantitative micro-anatomical phenotyping (qMAP) - that leverages deep learning and machine vision to fully label tissue and cellular compartments in tissue sections. The fully mapped tissue images address the challenges of finding an interpretable feature set to quantitatively profile age-related microanatomic changes. We optimized qMAP for skin tissues and applied it to a cohort of 99 donors aged 14 to 92. We extracted 914 microanatomic features and found that a broad spectrum of these features, represented by 10 cores processes, are strongly associated with aging. Our analysis shows that microanatomical features of the skin can predict aging with a mean absolute error (MAE) of 7.7 years, comparable to state-of-the-art epigenetic clocks. Our study demonstrates that tissue-level architectural changes are strongly associated with aging and represent a novel category of aging biomarkers that complement molecular markers. Our results highlight the complex and underexplored multi-scale relationship between molecular and tissue microanatomic scales.

Integrated transcriptomics of human blood vessels defines a spatially controlled niche for early mesenchymal progenitor cells.

Human blood vessel walls show concentric layers, with the outermost tunica adventitia harboring mesenchymal progenitor cells. These progenitor cells maintain vessel homeostasis and provide a robust cell source for cell-based therapies. However, human adventitial stem cell niche has not been studied in detail. Here, using spatial and single-cell transcriptomics, we characterized the phenotype, potential, and microanatomic distribution of human perivascular progenitors. Initially, spatial transcriptomics identified heterogeneity between perivascular layers of arteries and veins and delineated the tunica adventitia into inner and outer layers. From this spatial atlas, we inferred a hierarchy of mesenchymal progenitors dictated by a more primitive cell with a high surface expression of CD201 (PROCR). When isolated from humans and mice, CD201Low expression typified a mesodermal committed subset with higher osteogenesis and less proliferation than CD201High cells, with a downstream effect on canonical Wnt signaling through DACT2. CD201Low cells also displayed high translational potential for bone tissue generation.

Biosensors: An Upcoming Wave of Innovation.

SUMMARY: A biosensor uses a biological molecule to measure a chemical reaction. Wearable biosensors that attach to the body externally, including tooth enamel biosensors, contact lens biosensors, sweat biosensors, and skin tattoo biosensors, are in development. Nanoparticle-based biosensors are being developed to allow for the early detection of cancerous biomarkers. Applications relevant to plastic surgery include the development of biosensors that can detect metastatic breast cancer cells, bioimpedance spectroscopy, and intraoperative point-of-care diagnostics.

Artificial Intelligence: Singularity Approaches.

SUMMARY: Artificial intelligence (AI) has been a disruptive technology within health care, from the development of simple care algorithms to complex deep-learning models. AI has the potential to reduce the burden of administrative tasks, advance clinical decision-making, and improve patient outcomes. Unlocking the full potential of AI requires the analysis of vast quantities of clinical information. Although AI holds tremendous promise, widespread adoption within plastic surgery remains limited. Understanding the basics is essential for plastic surgeons to evaluate the potential uses of AI. This review provides an introduction of AI, including the history of AI, key concepts, applications of AI in plastic surgery, and future implications.

Screening for lipid nanoparticles that modulate the immune activity of helper T cells towards enhanced antitumour activity.

Lipid nanoparticles (LNPs) can be designed to potentiate cancer immunotherapy by promoting their uptake by antigen-presenting cells, stimulating the maturation of these cells and modulating the activity of adjuvants. Here we report an LNP-screening method for the optimization of the type of helper lipid and of lipid-component ratios to enhance the delivery of tumour-antigen-encoding mRNA to dendritic cells and their immune-activation profile towards enhanced antitumour activity. The method involves screening for LNPs that enhance the maturation of bone-marrow-derived dendritic cells and antigen presentation in vitro, followed by assessing immune activation and tumour-growth suppression in a mouse model of melanoma after subcutaneous or intramuscular delivery of the LNPs. We found that the most potent antitumour activity, especially when combined with immune checkpoint inhibitors, resulted from a coordinated attack by T cells and NK cells, triggered by LNPs that elicited strong immune activity in both type-1 and type-2 T helper cells. Our findings highlight the importance of optimizing the LNP composition of mRNA-based cancer vaccines to tailor antigen-specific immune-activation profiles.

Vascularized Denervated Muscle Targets for Headache Surgery-Presentation and Surgical Management.

Patients with substantial trauma to their occipital nerves and those with recurrent or persistent chronic headaches after occipital nerve decompression surgery require transection of their greater occipital and/or lesser occipital nerves to control debilitating pain. Current techniques, such as burying the transected nerve stump in nearby muscle, do not prevent neuroma formation, and more advanced techniques, such as targeted muscle reinnervation and regenerative peripheral nerve interface, have demonstrated only short-term anecdotal success in the context of headache surgery. Vascularized denervated muscle targets (VDMTs) are a novel technique to address the proximal nerve stump after nerve transection that has shown promise to improve chronic nerve pain and prevent neuroma formation. However, VDMTs have not been described in the context of headache surgery. Here authors describe the etiology, workup, and surgical management of 2 patients with recurrent occipital neuralgia who developed vexing neuromas after previous surgery and were successfully treated with VDMTs, remaining pain-free at 3-year follow-up.

Robotics in Plastic Surgery: It's Here.

SUMMARY: Although robotic surgery has been routinely established in other surgical disciplines, robotic technologies have been less readily adopted in plastic surgery. Despite a strong demand for innovation and cutting-edge technology in plastic surgery, most reconstructive procedures, including microsurgery, have continued to necessitate an open approach. Recent advances in robotics and artificial intelligence, however, are gaining momentum and have shown significant promise to improve patient care in plastic surgery. These next-generation surgical robots have the potential to enable surgeons to perform complex procedures with greater precision, flexibility, and control than previously possible with conventional techniques. Successful integration of robotic technologies into clinical practice in plastic surgery requires achieving key milestones, including implementing appropriate surgical education and garnering patient trust.

Cybersecurity and Technical Patient Privacy Protection.

Plastic surgery offices are subject to a wide variety of cybersecurity threats, including ransomware attacks that encrypt the plastic surgeon's information and make it unusable, as well as data theft and disclosure attacks that threaten to disclose confidential patient information. Cloud-based office systems increase the attack surface and do not mitigate the effects of breaches that can result in theft of credentials. Although employee education is often recommended to avoid the threats, a single error by a single employee has often led to security breaches, and it is not reasonable to expect that no employee will ever make an error. A recognition of the two most common vectors of these breaches, compromised email attachments and surfing to compromised websites, allows the use of technical networking tools to both prevent email attachments from being received and to prevent employee use of unsanctioned and potentially compromised websites. Further, once compromised code is allowed to run within the office network, that code must necessarily make outbound connections to exploit the breach. Preventing that outbound traffic can mitigate the effects of a breach. However, most small office network consultants design firewalls to only limit incoming network traffic and fail to implement technical measures to stop the unauthorized outbound traffic that is necessary for most network attacks. Detailed techniques are provided which can be used to direct IT consultants to properly limit outbound network traffic as well as incoming email attachments, with more information at https://officenetworksecurity.com.

Treatment of Persistent Post-traumatic Diplopia - An Algorithmic Approach to Patient Stratification and Operative Management.

Study Design: Retrospective chart review of revisional orbital surgery outcomes in patients with diplopia from prior operative treatment of orbital trauma. Objective: Our study seeks to review our experience with management of persistent post-traumatic diplopia in patients with previous orbital reconstruction and present a novel patient stratification algorithm predictive of improved outcomes. Methods: A retrospective chart review was performed on adult patients at Wilmer Eye Institute at Johns Hopkins Hospital and at the University of Maryland Medical Center who underwent revisional orbital surgery for correction of diplopia for the years 2005-2020. Restrictive strabismus was determined by Lancaster red-green testing coupled with computed tomography and/or forced duction. Globe position was assessed by computed tomography. Seventeen patients requiring operative intervention according to study criteria were identified. Results: Globe malposition affected fourteen patients and restrictive strabismus affected eleven patients. In this select group, improvement in diplopia occurred in 85.7% of cases with globe malposition and in 90.1% of cases with restrictive strabismus. One patient underwent additional strabismus surgery subsequent to orbital repair. Conclusions: Post-traumatic diplopia in patients with prior orbital reconstruction can be successfully managed in appropriate patients with a high degree of success. Indications for surgical management include (1) globe malposition and (2) restrictive strabismus. High resolution computer tomography and Lancaster red-green testing discriminate these from other causes that are unlikely to benefit from orbital surgery.

Colonizing microbiota is associated with clinical outcomes in diabetic wound healing.

With the development of society and the improvement of life quality, more than 500 million people are affected by diabetes. More than 10 % of people with diabetes will suffer from diabetic wounds, and 80 % of diabetic wounds will reoccur, so the development of new diabetic wound treatments is of great importance. The development of skin microbe research technology has gradually drawn people's attention to the complex relationship between microbes and diabetic wounds. Many studies have shown that skin microbes are associated with the outcome of diabetic wounds and can even be used as one of the indicators of wound prognosis. Skin microbes have also been found to have the potential to treat diabetic wounds. The wound colonization of different bacteria can exert opposing therapeutic effects. It is necessary to fully understand the skin microbes in diabetic wounds, which can provide valuable guidance for clinical diabetic wound treatment.

Breast Reconstruction Trends in the Setting of Postmastectomy Radiation Therapy: Analysis of Practices among Plastic Surgeons in the United States.

Radiation is an integral part of breast cancer therapy. The ideal type and timing of breast reconstruction with relation to radiation delivery are not well established. The study aimed to identify reconstructive practices among American plastic surgeons in the setting of pre- and postmastectomy radiation. Methods: A cross-sectional survey of members of the American Society of Plastic Surgery was performed. Practice/demographic information and breast reconstruction protocols were queried. Univariate descriptive statistics were calculated, and outcomes were compared across cohorts with χ2 and Fischer exact tests. Results: Overall, 477 plastic surgeons averaging 16.3 years in practice were surveyed. With respect to types of reconstruction, all options were well represented, although nearly 60% preferred autologous reconstruction with prior radiation and 55% preferred tissue expansion followed by implant/autologous reconstruction in the setting of unknown postoperative radiation. There was little consensus on the optimal timing of reconstruction in the setting of possible postoperative radiation. Most respondents wait 4-6 or 7-12 months between the end of radiation and stage 2 implant-based or autologous reconstruction. Common concerns regarding the effect of radiation on reconstructive outcomes included mastectomy flap necrosis, wound dehiscence, capsular contracture, tissue fibrosis, and donor vessel complications. Conclusions: Despite considerable research, there is little consensus on the ideal type and timing of reconstruction in the setting of pre- and postoperative radiation. Understanding how the current body of knowledge is translated into clinical practice by different populations of surgeons allows us to forge a path forward toward more robust, evidence-based guidelines for patient care.

A nanofiber-hydrogel composite improves tissue repair in a rat model of Crohn's disease perianal fistulas.

Perianal fistulas (PAFs) represent a severe complication of Crohn's disease (CD). Despite the advent of biologic and small-molecule therapeutics for luminal disease, PAFs in CD (CD-PAF) are relatively resistant to treatment, with less than 50% responding to any therapy. We report an injectable, biodegradable, mechanically fragmented nanofiber-hydrogel composite (mfNHC) loaded with adipose-derived stem cells (ADSCs) for the treatment of fistulas in a rat model of CD-PAF. The ADSC-loaded mfNHC results in a higher degree of healing when compared to surgical treatment of fistulas, which is a standard treatment. The volume of fistulas treated with mfNHC is decreased sixfold compared to the surgical treatment control. Molecular studies reveal that utilization of mfNHC reduced local inflammation and improved tissue regeneration. This study demonstrates that ADSC-loaded mfNHC is a promising therapy for CD-PAF, and warrants further studies to advance mfNHC toward clinical translation.

Commensal microbiome promotes hair follicle regeneration by inducing keratinocyte HIF-1α signaling and glutamine metabolism.

Tissue injury induces metabolic changes in stem cells, which likely modulate regeneration. Using a model of organ regeneration called wound-induced hair follicle neogenesis (WIHN), we identified skin-resident bacteria as key modulators of keratinocyte metabolism, demonstrating a positive correlation between bacterial load, glutamine metabolism, and regeneration. Specifically, through comprehensive multiomic analysis and single-cell RNA sequencing in murine skin, we show that bacterially induced hypoxia drives increased glutamine metabolism in keratinocytes with attendant enhancement of skin and hair follicle regeneration. In human skin wounds, topical broad-spectrum antibiotics inhibit glutamine production and are partially responsible for reduced healing. These findings reveal a conserved and coherent physiologic context in which bacterially induced metabolic changes improve the tolerance of stem cells to damage and enhance regenerative capacity. This unexpected proregenerative modulation of metabolism by the skin microbiome in both mice and humans suggests important methods for enhancing regeneration after injury.

Perforator Characteristics and Impact on Postoperative Outcomes in DIEP Flap Breast Reconstruction: A Systematic Review and Meta-Analysis.

BACKGROUND: High-quality evidence on perforator selection in deep inferior epigastric perforator (DIEP) flap harvesting is lacking, making preoperative planning and choice of perforators "surgeon-specific." This lack of consensus is a subject of continuous debate among microsurgeons. We aimed to systematically review perforator characteristics and their impact on DIEP flap breast reconstruction outcomes. METHODS: We conducted a systematic review and meta-analysis across six databases: ClinicalTrials.gov, Cochrane Library, Medline, Ovid Embase, PubMed, and Web of Science for all studies on DIEP flap breast reconstruction focused on perforator characteristics-caliber, number, and location. The primary goal was to analyze the impact of perforator characteristics on partial and/or total flap failure and fat necrosis. Data was analyzed using RevMan V5.3. RESULTS: Initial search gave us 2,768 articles of which 17 were included in our review. Pooled analysis did not show any statistically significant correlations between partial and/or total flap failure and perforator number, or perforator location. Sensitivity analysis accounting for heterogeneity across studies showed that, the risk for fat necrosis was significantly higher if single perforators (relative risk [RR] = 2.0, 95% confidence interval [CI] = 1.5-2.6, I 2 = 39%) and medial row perforators (RR = 2.7, 95% CI = 1.8-3.9, I 2 = 0%) were used. CONCLUSION: Our findings suggest that a single dominant perforator and medial row perforators may be associated with higher risk of fat necrosis after DIEP flap breast reconstruction. Adopting a standardized perforator selection algorithm may facilitate operative decision making, shorten the learning curve for novice surgeons, and optimize postoperative outcomes by minimizing the burden of major complications. This in turn would help improve patient satisfaction and quality of life.

A 10-Year Review of Surgical Outcomes at the Johns Hopkins and University of Maryland Resident Aesthetic Clinic.

Background: In 2014, the Plastic Surgery Residency Review Committee of the Accreditation Council for Graduate Medical Education (ACGME) increased minimum aesthetic surgery requirements. Consequently, the resident aesthetic clinic (RAC) has become an ever more important modality for training plastic surgery residents. Objectives: To analyze demographics and long-term surgical outcomes of aesthetic procedures performed at the Johns Hopkins and University of Maryland (JH/UM) RAC. A secondary objective was to evaluate the JH/UM RAC outcomes against those of peer RACs as well as board-certified plastic surgeons. Methods: We performed a retrospective chart review of all patients who underwent aesthetic procedures at the JH/UM RAC between 2011 and 2020. Clinical characteristics, minor complication rates, major complication rates, and revision rates from the JH/UM RAC were compared against 2 peer RACs. We compared the incidence of major complications between the JH/UM RAC and a cohort of patients from the CosmetAssure (Birmingham, AL) database. Pearson's chi-square test was used to compare complication rates between patient populations, with a significance set at 0.05. Results: Four hundred ninety-five procedures were performed on 285 patients. The major complications rate was 1.0% (n = 5). Peer RACs had total major complication rates of 0.2% and 1.7% (P = .07 and P = .47, respectively). CosmetAssure patients matched to JH/UM RAC patients were found to have comparable total major complications rates of 1.8% vs 0.6% (P = .06), respectively. At JH/UM, the minor complication rate was 13.9%, while the revision rate was 5.9%. Conclusions: The JH/UM RAC provides residents the education and training necessary to produce surgical outcomes comparable to peer RACs as well as board-certified plastic surgeons.

CODA: quantitative 3D reconstruction of large tissues at cellular resolution.

A central challenge in biology is obtaining high-content, high-resolution information while analyzing tissue samples at volumes relevant to disease progression. We address this here with CODA, a method to reconstruct exceptionally large (up to multicentimeter cubed) tissues at subcellular resolution using serially sectioned hematoxylin and eosin-stained tissue sections. Here we demonstrate CODA's ability to reconstruct three-dimensional (3D) distinct microanatomical structures in pancreas, skin, lung and liver tissues. CODA allows creation of readily quantifiable tissue volumes amenable to biological research. As a testbed, we assess the microanatomy of the human pancreas during tumorigenesis within the branching pancreatic ductal system, labeling ten distinct structures to examine heterogeneity and structural transformation during neoplastic progression. We show that pancreatic precancerous lesions develop into distinct 3D morphological phenotypes and that pancreatic cancer tends to spread far from the bulk tumor along collagen fibers that are highly aligned to the 3D curves of ductal, lobular, vascular and neural structures. Thus, CODA establishes a means to transform broadly the structural study of human diseases through exploration of exhaustively labeled 3D microarchitecture.

Biostimulatory Micro-Fragmented Nanofiber-Hydrogel Composite Improves Mesenchymal Stem Cell Delivery and Soft Tissue Remodeling.

Functional microgels are preferred stem cell carriers due to the ease of delivery through minimally invasive injection and seamless integration with the surrounding host tissue. A biostimulatory nanofiber-hydrogel composite (NHC) has been previously developed through covalently crosslinking a hyaluronic acid hydrogel network with surface-functionalized poly (ε-caprolactone) nanofiber fragments. The NHC mimics the microarchitecture of native soft tissue matrix, showing enhanced cell infiltration, immunomodulation, and proangiogenic properties. Here, injectability of the pre-formed NHC is improved by mechanical fragmentation, making it into micro-fragmented NHC (mfNHC) in a granular gel form as a stem cell carrier to deliver mesenchymal stem cells (MSCs) for soft tissue remodeling. The mfNHC shows a similar storage modulus but a significantly reduced injection force, as compared with the corresponding bulk NHC. When injected subcutaneously in a rat model, mfNHC-MSC constructs initiate an elevated level of host macrophage infiltration, more pro-regenerative polarization, and subsequently, improved angiogenesis and adipogenesis response when compared to mfNHC alone. A similar trend of host cell infiltration and pro-angiogenic response is detected in a swine model with a larger volume injection. These results suggest a strong potential for use of the mfNHC as an injectable carrier for cell delivery and soft tissue remodeling.

Multi-step screening of DNA/lipid nanoparticles and co-delivery with siRNA to enhance and prolong gene expression.

Lipid nanoparticles hold great potential as an effective non-viral vector for nucleic acid-based gene therapy. Plasmid DNA delivery can result in extended transgene expression compared to mRNA-based technologies, yet there is a lack of systematic investigation into lipid nanoparticle compositions for plasmid DNA delivery. Here, we report a multi-step screening platform to identify optimized plasmid DNA lipid nanoparticles for liver-targeted transgene expression. To achieve this, we analyze the role of different helper lipids and component ratios in plasmid DNA lipid nanoparticle-mediated gene delivery in vitro and in vivo. Compared to mRNA LNPs and in vivo-jetPEI/DNA nanoparticles, the identified plasmid DNA lipid nanoparticles successfully deliver transgenes and mediate prolonged expression in the liver following intravenous administration in mice. By addressing different physiological barriers in a stepwise manner, this screening platform can efficiently down select effective lipid nanoparticle candidates from a lipid nanoparticle library of over 1000 formulations. In addition, we substantially extend the duration of plasmid DNA nanoparticle-mediated transgene expression using a DNA/siRNA co-delivery approach that targets transcription factors regulating inflammatory response pathways. This lipid nanoparticle-based co-delivery strategy further highlights the unique advantages of an extended transgene expression profile using plasmid DNA delivery and offers new opportunities for DNA-based gene medicine applications.

Toward Understanding Wound Immunology for High-Fidelity Skin Regeneration.

Effective tissue repair is vital for the survival of organisms. Yet, how the immune system coordinates with tissue stem cells (SCs) to effect postnatal tissue restoration remains elusive. This review presents current knowledge surrounding wound-induced SC and immune signaling that favors tissue repair, including wound healing and regeneration. We discuss factors that affect regenerative capacities among organisms and the dynamics of local immune cells and SCs during reepithelialization. We also present recent insights into how immune niches communicate with SCs or other body systems to restore the epithelial architecture. Additionally, we summarize our findings on functional wound regeneration, specifically how alarmin (double-stranded RNA [dsRNA])-activated Toll-like receptor signaling and host-microbe interaction-related immune pathways alter the regenerative property of skin SCs. Last, we touch on mechanisms by which known immunologic cellular and molecular signaling might boost the skin's regenerative property. Overall, this review will provide insights into how therapeutically modulating immune signaling could enhance postnatal tissue regeneration.