Injectable Antioxidant and Oxygen-Releasing Lignin Composites to Promote Wound Healing.

The application of engineered biomaterials for wound healing has been pursued since the beginning of tissue engineering. Here, we attempt to apply functionalized lignin to confer antioxidation to the extracellular microenvironments of wounds and to deliver oxygen from the dissociation of calcium peroxide for enhanced vascularization and healing responses without eliciting inflammatory responses. Elemental analysis showed 17 times higher quantity of calcium in the oxygen-releasing nanoparticles. Lignin composites including the oxygen-generating nanoparticles released around 700 ppm oxygen per day at least for 7 days. By modulating the concentration of the methacrylated gelatin, we were able to maintain the injectability of lignin composite precursors and the stiffness of lignin composites suitable for wound healing after photo-cross-linking. In situ formation of lignin composites with the oxygen-releasing nanoparticles enhanced the rate of tissue granulation, the formation of blood vessels, and the infiltration of α-smooth muscle actin+ fibroblasts into the wounds over 7 days. At 28 days after surgery, the lignin composite with oxygen-generating nanoparticles remodeled the collagen architecture, resembling the basket-weave pattern of unwounded collagen with minimal scar formation. Thus, our study shows the potential of functionalized lignin for wound-healing applications requiring balanced antioxidation and controlled release of oxygen for enhanced tissue granulation, vascularization, and maturation of collagen.

Endogenous Interleukin-10 Contributes to Wound Healing and Regulates Tissue Repair.

INTRODUCTION: Interleukin-10 (IL-10) is essential in fetal regenerative wound healing and likewise promotes a regenerative phenotype in adult dermal wounds. However, the role of endogenous IL-10 in postnatal dermal wound healing is not well-established. We sought to determine the function of endogenous IL-10 in murine full thickness excisional wounds that are splinted to prevent contracture and mimic human patterns of wound closure. METHODS: Full-thickness excisional wounds were made in wildtype (WT) and IL-10-/- mice on a C57BL/6J background (F/M, 8 wk old). In a subset of wounds, contraction was prevented by splinting with silicone stents (stenting) and maintaining a moist wound microenvironment using a semiocclusive dressing. Wounds were examined for re-epithelialization, granulation tissue deposition, and inflammatory cell infiltrate at day 7 and fibrosis and scarring at day 30 postwounding. RESULTS: We observed no difference in wound healing rate between WT and IL-10-/- mice in either the stented or unstented group. At day 7, unstented IL-10-/- wounds had a larger granulation tissue area and more inflammatory infiltrate than their WT counterparts. However, we did observe more F4/80+ cell infiltrate in stented IL-10-/- wounds at day 7. At day 30, stented wounds had increased scar area and epithelial thickness compared to unstented wounds. CONCLUSIONS: These data suggest that endogenous IL-10 expression does not alter closure of full thickness excisional wounds when wound hydration and excessive contraction of murine skin are controlled. However, the loss of IL-10 leads to increased inflammatory cell infiltration and scarring. These new findings suggest that IL-10 contributes to the regulation of inflammation without compromising the healing response. These data combined with previous reports of increased rates of healing in IL-10-/- mice wounds not controlled for hydration and contraction suggest an important role for murine wound healing models used in research studies of molecular mechanisms that regulate healing.

Current state of the art in hypoplastic left heart syndrome.

Hypoplastic left heart syndrome (HLHS) is a complex congenital heart condition in which a neonate is born with an underdeveloped left ventricle and associated structures. Without palliative interventions, HLHS is fatal. Treatment typically includes medical management at the time of birth to maintain patency of the ductus arteriosus, followed by three palliative procedures: most commonly the Norwood procedure, bidirectional cavopulmonary shunt, and Fontan procedures. With recent advances in surgical management of HLHS patients, high survival rates are now obtained at tertiary treatment centers, though adverse neurodevelopmental outcomes remain a clinical challenge. While surgical management remains the standard of care for HLHS patients, innovative treatment strategies continue to be developing. Important for the development of new strategies for HLHS patients is an understanding of the genetic basis of this condition. Another investigational strategy being developed for HLHS patients is the injection of stem cells within the myocardium of the right ventricle. Recent innovations in tissue engineering and regenerative medicine promise to provide important tools to both understand the underlying basis of HLHS as well as provide new therapeutic strategies. In this review article, we provide an overview of HLHS, starting with a historical description and progressing through a discussion of the genetics, surgical management, post-surgical outcomes, stem cell therapy, hemodynamics and tissue engineering approaches.

Advances in non-invasive biosensing measures to monitor wound healing progression.

Impaired wound healing is a significant financial and medical burden. The synthesis and deposition of extracellular matrix (ECM) in a new wound is a dynamic process that is constantly changing and adapting to the biochemical and biomechanical signaling from the extracellular microenvironments of the wound. This drives either a regenerative or fibrotic and scar-forming healing outcome. Disruptions in ECM deposition, structure, and composition lead to impaired healing in diseased states, such as in diabetes. Valid measures of the principal determinants of successful ECM deposition and wound healing include lack of bacterial contamination, good tissue perfusion, and reduced mechanical injury and strain. These measures are used by wound-care providers to intervene upon the healing wound to steer healing toward a more functional phenotype with improved structural integrity and healing outcomes and to prevent adverse wound developments. In this review, we discuss bioengineering advances in 1) non-invasive detection of biologic and physiologic factors of the healing wound, 2) visualizing and modeling the ECM, and 3) computational tools that efficiently evaluate the complex data acquired from the wounds based on basic science, preclinical, translational and clinical studies, that would allow us to prognosticate healing outcomes and intervene effectively. We focus on bioelectronics and biologic interfaces of the sensors and actuators for real time biosensing and actuation of the tissues. We also discuss high-resolution, advanced imaging techniques, which go beyond traditional confocal and fluorescence microscopy to visualize microscopic details of the composition of the wound matrix, linearity of collagen, and live tracking of components within the wound microenvironment. Computational modeling of the wound matrix, including partial differential equation datasets as well as machine learning models that can serve as powerful tools for physicians to guide their decision-making process are discussed.

Impact of Telemedicine on Prenatal Counseling at a Tertiary Fetal Center: A Mixed Methods Study.

INTRODUCTION: COVID-19 spurred an unprecedented transition from in-person to telemedicine visits in March 2020 at our institution for all prenatal counseling sessions. This study aims to explore differences in demographics of expectant mothers evaluated pre- and post-telemedicine implementation and to explore the patient experience with telemedicine. METHODS: A mixed methods study was completed for mothers with a pregnancy complicated by a fetal surgical anomaly who visited a large tertiary fetal center. Using medical records as quantitative data, patient information was collected for all prenatal visits from 3/2019 to 3/2021. The sample was grouped into pre- and post-telemedicine implementation (based on transition date of 3/2020). Univariate analysis was used to compare demographics between the study groups. Statistical significance was defined as P < 0.05. Eighteen semi-structured interviews were conducted from 8/2021 to 12/2021 to explore patients' experiences. Line-by-line coding and thematic analysis was performed to develop emerging themes. RESULTS: 292 pregnancies were evaluated from 3/2019 to 3/2021 (pre-telemedicine 123, post-telemedicine 169). There was no significant difference in self-reported race (P = 0.28), ethnicity (P = 0.46), or primary language (P = 0.98). In qualitative interviews, patients reported advantages to telemedicine, including the convenience of the modality with the option to conduct their session in familiar settings (e.g., home) and avoid stressors (e.g., travel to the medical center and finding childcare). Some women reported difficulties establishing a physician-patient connection and a preference for in-person consultations. CONCLUSIONS: There was no difference in patient demographics at our fetal center in the year leading up to, and the time following, a significant transition to telemedicine. However, patients had unique perspectives on the advantages and disadvantages of the telemedicine experience. To ensure patient centered care, these findings suggest patient preference should be considered when scheduling outpatient surgical counseling and visits.

Maternal Steroids in High-Risk Congenital Lung Malformations.

INTRODUCTION: The purpose of the present study is to evaluate our institutional management of high-risk congenital lung malformations (CLM) with particular consideration of the use of multiple maternal steroid courses and maternal steroids in CLMs with pathologies other than congenital pulmonary airway malformation (CPAM). METHODS: A single-center retrospective review was performed for all fetuses evaluated for CLM who received maternal steroids and/or had a CLM volume ratio (CVR) ≥ 1.6 (2015-2020). Fetuses were categorized as receiving no steroids, single steroid, or multiple steroid courses. Outcomes evaluated included CVR growth rate, resolution of early hydrops, and resolution of hydrops. Results are reported with a descriptive analysis. RESULTS: Nineteen patients were identified who had CVR ≥ 1.6 (single steroid course 9/19, multiple steroid courses 6/19, and no steroids 4/19). A majority (n = 13, 68%) of all lesions had a reduction or no change in CVR between initial and final measurements (single steroid course 7/9, 78%; multiple steroid courses 4/6, 67%). When evaluating by pathology, ≥ 50% of each classification had reduction or no growth of CVR (CPAM 7/11, bronchial atresia 2/4, sequestration 3/3, congenital lobar emphysema 1/1). Seventy five percent (3/4) of lesions with early hydrops had resolution following steroid treatment (single steroid course 1, multiple steroid courses 2). Of the four lesions that had hydrops, only one had resolution after receiving multiple steroid courses. CONCLUSIONS: Our institutional experience reports the majority of CLM (including pathologies other than CPAM) who received steroids had reduction or no change in CVR. Given the low risk-benefit ratio of maternal steroids, physicians could consider use of multiple steroid courses for CLM refractory to a single course.

The Cellular and Molecular Effects of Fetoscopic Endoluminal Tracheal Occlusion in Congenital Diaphragmatic Hernia.

Congenital diaphragmatic hernia (CDH) is a complex disease associated with pulmonary hypoplasia and pulmonary hypertension. Great strides have been made in our ability to care for CDH patients, specifically in the prenatal improvement of lung volume and morphology with fetoscopic endoluminal tracheal occlusion (FETO). While the anatomic effects of FETO have been described in-depth, the changes it induces at the cellular and molecular level remain a budding area of CDH research. This review will delve into the cellular and molecular effects of FETO in the developing lung, emphasize areas in which further research may improve our understanding of CDH, and highlight opportunities to optimize the FETO procedure for improved postnatal outcomes.

IL-10 promotes endothelial progenitor cell infiltration and wound healing via STAT3.

Endothelial progenitor cells (EPCs) contribute to de novo angiogenesis, tissue regeneration, and remodeling. Interleukin 10 (IL-10), an anti-inflammatory cytokine that primarily signals via STAT3, has been shown to drive EPC recruitment to injured tissues. Our previous work demonstrated that overexpression of IL-10 in dermal wounds promotes regenerative tissue repair via STAT3-dependent regulation of fibroblast-specific hyaluronan synthesis. However, IL-10's role and specific mode of action on EPC recruitment, particularly in dermal wound healing and neovascularization in both normal and diabetic wounds, remain to be defined. Therefore, inducible skin-specific STAT3 knockdown mice were studied to determine IL-10's impact on EPCs, dermal wound neovascularization and healing, and whether it is STAT3-dependent. We show that IL-10 overexpression significantly elevated EPC counts in the granulating wound bed, which was associated with robust capillary lumen density and enhanced re-epithelialization of both control and diabetic (db/db) wounds at day 7. We noted increased VEGF and high C-X-C motif chemokine 12 (CXCL12) levels in wounds and a favorable CXCL12 gradient at day 3 that may support EPC mobilization and infiltration from bone marrow to wounds, an effect that was abrogated in STAT3 knockdown wounds. These findings were supported in vitro. IL-10 promoted VEGF and CXCL12 synthesis in primary murine dermal fibroblasts, with blunted VEGF expression upon blocking CXCL12 in the media by antibody binding. IL-10-conditioned fibroblast media also significantly promoted endothelial sprouting and network formation. In conclusion, these studies demonstrate that overexpression of IL-10 in dermal wounds recruits EPCs and leads to increased vascular structures and faster re-epithelialization.

Correlation of continence with long-term patient centered outcomes in children with sacrococcygeal teratoma.

PURPOSE: The purpose of this study is to evaluate the relationship of social continence with patient centered outcomes, such as quality of life, in children with sarococcygeal teratoma (SCT). We hypothesize there is a correlation between social continence and patient-centered outcomes. METHODS: A chart review and three surveys (Pediatric Quality of Life Inventory™ (PedsQL™), Baylor Continence Scale (BCS), and Impact on Family (IOF)) were performed for SCT patients who underwent resection at our institution from 2013 to 2018. PedsQL™ assesses quality of life, BCS evaluates global continence, and the IOF scale measures the impact of a child's illness on the family. Pearson correlation was used to examine the relationship between BCS, PedsQL™, and IOF. RESULTS: Eighteen patients were identified with 72% (13/18) participating in the surveys with a median age at time of survey of 4.7 years (range 2.8-7.9). Patients with Altman IV were diagnosed postnatally and had smaller tumors. At the time of survey administration, a majority of children were toilet trained (54%, 7/13). Parents reported urinary incontinence (46%, 6/13) more frequently than bowel incontinence (15%, 2/13). Altman III/IV trended towards worse PedsQL™, BCS, and IOF surveys; however, it was not significant. The BCS correlated with the Total PedsQL™ (ρ = -0.56, p = 0.048) and IOF (ρ = 0.68, p = 0.011). CONCLUSION: Children with SCT have a correlation between social continence, quality of life, and the impact on family. This study suggests interventions to screen and improve continence in children with SCT could also improve patient centered metrics. STUDY DESIGN: Cross-sectional study LEVEL OF EVIDENCE: Level II, Prognosis Study.

Delivery planning for congenital lung malformations: A CVR based perinatal care algorithm.

PURPOSE: Congenital lung malformation (CLM) volume ratio (CVR) of ≥1.1 has been shown to be highly predictive of the need for urgent, perinatal surgical intervention. The purpose of this study was to utilize this information to propose a delivery planning and clinical management algorithm based on this threshold. METHODS: A retrospective cohort study was performed for all fetuses evaluated at our fetal center between 5/2015 and 11/2020. Demographics, ultrasound findings, late gestation CVR (≥27 weeks gestational age), prenatal and postnatal treatment, and outcomes were analyzed with nonparametric univariate analysis based on late gestation CVR of 1.1. Receiver operating characteristic curve analysis was performed to evaluate association between late gestation CVR, hydrops, need for fetal intervention, and need for urgent perinatal surgery. RESULTS: Of the 90 CLMs referred to our fetal center, 65 had late gestation CVR with a majority <1.1 (47/65, 72%). All patients with late gestation CVR ≥ 1.1 were managed with resection (18/18) with most resections requiring fetal intervention or urgent neonatal resection (13/18). Late gestation CVR < 1.1 were managed with elective resection (36/47, 77%) or non-operative observation (11/47, 23%). Late gestation CVR ≥ 1.1 had 100% sensitivity and NPV for hydrops, need for fetal intervention, and need for urgent perinatal surgery. CONCLUSION: CLM with CVR ≥ 1.1 were associated with urgent perinatal surgical intervention and expectant mothers should plan for delivery at centers equipped to manage neonatal resuscitation and potential urgent neonatal resection. Conversely, CLM with CVR < 1.1 may be safe to deliver at patient hospital of choice.

Strategies to Minimize Surgical Scarring: Translation of Lessons Learned from Bedside to Bench and Back.

Significance: An understanding of the physiology of wound healing and scarring is necessary to minimize surgical scar formation. By reducing tension across the healing wound, eliminating excess inflammation and infection, and encouraging perfusion to healing areas, surgeons can support healing and minimize scarring. Recent Advances: Preoperatively, newer techniques focused on incision placement to minimize tension, skin sterilization to minimize infection and inflammation, and control of comorbid factors to promote a healing process with minimal scarring are constantly evolving. Intraoperatively, measures like layered closure, undermining, and tissue expansion can be taken to relieve tension across the healing wound. Appropriate suture technique and selection should be considered, and finally, there are new surgical technologies available to reduce tension across the closure. Postoperatively, the healing process can be supported as proliferation and remodeling take place within the wound. A balance of moisture control, tension reduction, and infection prevention can be achieved with dressings, ointments, and silicone. Vitamins and corticosteroids can also affect the scarring process by modulating the cellular factors involved in healing. Critical Issues: Healing with no or minimal scarring is the ultimate goal of wound healing research. Understanding how mechanical tension, inflammation and infection, and perfusion and hypoxia impact profibrotic pathways allows for the development of therapies that can modulate cytokine response and the wound extracellular microenvironment to reduce fibrosis and scarring. Future Directions: New tension-off loading topical treatments, laser, and dermabrasion devices are under development, and small molecule therapeutics have demonstrated scarless wound healing in animal models, providing a promising new direction for future research aimed to minimize surgical scarring.

The Role of T Lymphocytes in Cutaneous Scarring.

Significance: Cutaneous scarring affects millions of patients worldwide and results in significant financial and psychosocial burdens. Given the immune system's intricate involvement in the initiation and progression of wound healing, it is no surprise that the scarring outcome can be affected by the actions of various immune cells and the cytokines and growth factors they produce. Understanding the role of T cells in regulating immune responses and directing the action of wound mesenchymal cells is essential to developing antifibrotic therapies to reduce the burden of scarring. Recent Advances: As the immune system is intimately involved in wound healing, much work has examined the impact of T cells and their cytokines on the final wound outcome. New innovative tools for studying T cells have resulted in more sophisticated immunophenotyping capabilities and the ability to examine effects of individual cytokines in the wound environment. Critical Issues: Despite continued advances in the study of specific immune cells and their effects on dermal fibrosis, minimal progress has been made to modulate immune responses to result in improved wound cosmesis. Future Directions: The actions of T cells represent potential pharmacologic targets that could lead to novel bioengineered or immunoengineered therapies to improve the lives of people with cutaneous scarring.

Interleukin-10 Producing T Lymphocytes Attenuate Dermal Scarring.

OBJECTIVE: Demonstrate the impact of IL-10 producing T lymphocytes on mediating dermal scarring. SUMMARY BACKGROUND DATA: We demonstrated that CD4+ cells are essential to improving postinjury wound healing and preventing fibrosis. CD4+ subsets secrete differential cytokine and growth factor profiles, though their role in fibrosis is not known. IL-10, a key anti-inflammatory cytokine shown to promote regenerative wound healing, is secreted by some CD4+ subsets. We, therefore, hypothesize that IL-10 producing CD4+ T lymphocyte subsets selectively attenuate dermal wound fibrosis. METHODS: IL-10-/- and wild-type murine splenocytes were enriched for CD4+ lymphocytes and adoptively transferred into severe combined immunodeficient (SCID) mice that received full-thickness wounds which were analyzed at days 7 and 28 for inflammation and collagen content. We then sorted CD4+CD44int/lowFoxP3-CD62L+ T cells (Tnaive) or CD4+CD44HiFoxP3- type 1 regulatory (Tr1) T cell subsets from 10BiT murine splenocytes, activated them, and transferred them into wounds. In vitro, dermal fibroblasts were cocultured with Tnaive or Tr1 and the effect on extracellular matrix (ECM) regulation was analyzed. RESULTS: The anti-inflammatory and antifibrotic effects of CD4+ cells on SCID wounds were lost with cells from IL-10-/- mice. Adoptive transfer of Tr1 into SCID mice resulted in accelerated wound closure at d7 with reduced fibrosis at d28, with Tr1 favoring hyaluronan production by fibroblasts, an ECM molecule implicated in IL-10-induced regenerative healing. CONCLUSIONS: IL-10 producing T-lymphocytes, specifically Tr1, regulate inflammatory cell cytokine expression to promote HA-rich ECM deposition and attenuate fibrosis. Promoting IL-10 producing lymphocytes in wounds may be a therapeutic target to promote regenerative wound healing.

Immunologic Roles of Hyaluronan in Dermal Wound Healing.

Hyaluronic acid (HA), a glycosaminoglycan ubiquitous in the skin, has come into the limelight in recent years for its role in facilitating dermal wound healing. Specifically, HA's length of linearly repeating disaccharides-in other words, its molecular weight (MW)-determines its effects. High molecular weight (HMW)-HA serves an immunosuppressive and anti-inflammatory role, whereas low molecular weight (LMW)-HA contributes to immunostimulation and thus inflammation. During the inflammatory stage of tissue repair, direct and indirect interactions between HA and the innate and adaptive immune systems are of particular interest for their long-lasting impact on wound repair. This review seeks to synthesize the literature on wound healing with a focus on HA's involvement in the immune subsystems.

Hyaluronidases in Human Diseases.

With the burgeoning interest in hyaluronic acid (HA) in recent years, hyaluronidases (HYALs) have come to light for their role in regulating catabolism of HA and its molecular weight (MW) distribution in various tissues. Of the six hyaluronidase-like gene sequences in the human genome, HYALs 1 and 2 are of particular significance because they are the primary hyaluronidases active in human somatic tissue. Perhaps more importantly, for the sake of this review, they cleave anti-inflammatory and anti-fibrotic high-molecular-weight HA into pro-inflammatory and pro-fibrotic oligosaccharides. With this, HYALs regulate HA degradation and thus the development and progression of various diseases. Given the dearth of literature focusing specifically on HYALs in the past decade, this review seeks to expound their role in human diseases of the skin, heart, kidneys, and more. The review will delve into the molecular mechanisms and pathways of HYALs and discuss current and potential future therapeutic benefits of HYALs as a clinical treatment.

Skin-specific knockdown of hyaluronan in mice by an optimized topical 4-methylumbelliferone formulation.

Hyaluronan (HA) is abundant in the skin; while HA can be synthesized by the synthases (HAS1-3), HAS2 is the leading contributor. Dysregulation and accumulation of HA is implicated in the pathogenesis of diseases such as keloid scarring, lymphedema and metastatic melanoma. To understand how HA synthesis contributes to skin physiology, and pathologic and fibrotic disorders, we propose the development of skin-specific HA inhibition model, which tests an optimal delivery system of topical 4-methylumbelliferone (4-MU). A design-of-experiments (DOE) approach was employed to develop an optimal 4-MU skin-delivery formulation comprising propylene glycol, ethanol, and water, topically applied to dorsal skin in male and female C57BL/6J wildtype mice to determine the effect on HAS gene expression and HA inhibition. Serum and skin samples were analyzed for HA content along with analysis of expression of HAS1-3, hyaluronidases (HYAL 1-2), and KIAA1199. Using results from DOE and response surface methodology with genetic algorithm optimization, we developed an optimal topical 4-MU formulation to result in ∼70% reduction of HA in dorsal skin, with validation demonstrating ∼50% reduction in HA in dorsal skin. 4-MU topical application resulted in significant decrease in skin HAS2 expression in female mice only. Histology showed thicker dermis in male mice, whereas female mice had thinner dermal layer with more adiposity; and staining for HA-binding protein showed that topical 4-MU resulted in breakdown in HA. Our data suggest a topical 4-MU formulation-based dermal HA inhibition model that would enable elucidating the skin-specific effects of HA in normal and pathologic states.