Targeting Inflammation and Oxidative Stress to Improve Outcomes in a TNBS Murine Crohn's Colitis Model.

Inflammation and oxidative stress are implicated in the pathogenesis of Crohn's disease. Cerium oxide nanoparticle (CNP) conjugated to microRNA 146a (miR146a) (CNP-miR146a) is a novel compound with anti-inflammatory and antioxidative properties. We hypothesized that local administration of CNP-miR146a would improve colitis in a 2,4,6-Trinitrobenzenesulfonic acid (TNBS) mouse model for Crohn's disease by decreasing colonic inflammation. Balb/c mice were instilled with TNBS enemas to induce colitis. Two days later, the mice received cellulose gel enema, cellulose gel with CNP-miR146a enema, or no treatment. Control mice received initial enemas of 50% ethanol and PBS enemas on day two. The mice were monitored daily for weight loss and clinical disease activity. The mice were euthanized on days two or five to evaluate their miR146a expression, inflammation on histology, and colonic IL-6 and TNF gene expressions and protein concentrations. CNP-miR146a enema successfully increased colonic miR146a expression at 12 h following delivery. At the end of five days from TNBS instillation, the mice treated with CNP-miR146a demonstrated reduced weight loss, improved inflammation scores on histology, and reduced gene expressions and protein concentrations of IL-6 and TNF. The local delivery of CNP-miR146a in a TNBS mouse model of acute Crohn's colitis dramatically decreased inflammatory signaling, resulting in improved clinical disease.

Dysregulation of miRNA-mRNA expression in fetal growth restriction in a caloric restricted mouse model.

Fetal growth restriction (FGR) is associated with aberrant placentation and accounts for a significant proportion of perinatal deaths. microRNAs have been shown to be dysregulated in FGR. The purpose of this study was to determine microRNA-regulated molecular pathways altered using a caloric restricted mouse model of FGR. Pregnant mice were subjected to a 50% caloric restricted diet beginning at E9. At E18.5, RNA sequencing of placental tissue was performed to identify differences in gene expression between caloric restricted and control placentas. Significant differences in gene expression between caloric restricted and control placentas were observed in 228 of the 1546 (14.7%) microRNAs. Functional analysis of microRNA-mRNA interactions demonstrated enrichment of several biological pathways with oxidative stress, apoptosis, and autophagy pathways upregulated and angiogenesis and signal transduction pathways downregulated. Ingenuity pathway analysis also suggested that ID1 signaling, a pathway integral for trophoblast differentiation, is also dysregulated in caloric restricted placentas. Thus, a maternal caloric restriction mouse model of FGR results in aberrant microRNA-regulated molecular pathways associated with angiogenesis, oxidative stress, signal transduction, apoptosis, and cell differentiation. As several of these pathways are dysregulated in human FGR, our findings suggest that this model may provide an excellent means to study placental microRNA derangements seen in FGR.

In utero Diagnosis of Spinal Dermal Sinus.

INTRODUCTION: Congenital dermal sinus (CDS) is an open neural tube defect (NTD) that occurs in 1 in 2,500 births a year and often goes undetected until patients present with complications like infection and neurological deficits. Early diagnosis and repair of CDS may prevent formation of these complications. In utero diagnosis of these lesions may improve long-term outcomes by enabling referral to specialty services and planned postnatal repair; however, only 2 such cases have been reported in the literature. We present a third case of in utero diagnosis of CDS with a description and discussion of findings from surgical exploration and pathology. CASE PRESENTATION: Routine prenatal ultrasound scan detected a tethered cystic structure arising from the back of the fetus at 20 weeks of gestation. Dedicated fetal ultrasound confirmed the presence of a cystic lesion protruding through a lamina defect, while fetal magnetic resonance imaging showed an intact spinal cord and meninges, suggesting a diagnosis of CDS. Neurosurgery followed along closely and took the child for surgical exploration on day 2 of life. A fibrous stalk with an intradural component and associated cord tethering was excised. Histology showed fibrous tissue without an epithelial-lined lumen. CONCLUSION: CDS is a form of NTD that occurs from nondisjunction of the cutaneous ectoderm and neuroectoderm during formation of the neural tube. Slight differences in how this error occurs can explain variations seen in this spectrum of disease, including CDS without an epithelial-lined lumen as seen in this case. Newborns with CDS can go undiagnosed for years and present with long-term complications. Fetal imaging can assist in early recognition and surgical excision of CDS in newborns.

Surgical Necrotizing Enterocolitis - Can We Predict the Need for Gastrostomy Tube Placement?

INTRODUCTION: Necrotizing enterocolitis (NEC) is a significant cause of morbidity and mortality among extremely premature infants. Approximately 50% of cases progress to surgery, frequently resulting in resection of necrotic bowel and ostomy creation. Premature neonates are at risk for bronchopulmonary dysplasia and feeding failure; surgery in these patients is higher risk. We evaluated the incidence of gastrostomy tube (GT) placement after ostomy reversal in surgical NEC to define a subset of patients who would benefit from concurrent ostomy reversal and GT placement. METHODS: A single-center retrospective study of infants with surgical NEC requiring ostomy creation between 2007 and 2021 was performed. RESULTS: Eighty patients met inclusion criteria. A GT was placed in 45/80 (56.3%), of which 3/45 (6.7%) were placed before, 20/45 (44.4%) concurrently with, and 22/45 (48.9%) after ostomy reversal. Between those who did and did not require GT placement, there were no significant differences in gestational age (27 versus 27 wk, P = 0.94) or birth weight (830 g versus 1055 g, P = 0.36). Hospital length of stay was longer in the GT group (128.2 versus 70.9 d, P < 0.0001). Time from ostomy reversal to hospital discharge was shorter when performed concurrently with GT (56 versus 77 d, P = 0.02). There were no differences in short-term or long-term GT related complications based on timing of GT placement. CONCLUSIONS: GT placement occurred in approximately 50% of patients with surgical NEC and GT may be accomplished safely at the time of ostomy reversal thus reducing the need for an additional procedure.

Muscle Flap Technique Safe for On-ECMO Congenital Diaphragmatic Hernia Repair.

INTRODUCTION: Prosthetic patches (patch) and muscle flaps (flap) are techniques used for repair of congenital diaphragmatic hernia (CDH) with a large defect unamenable to primary closure. We hypothesized that the flap technique for CDH repair while on extra-corporeal membrane oxygenation (on-ECMO) would have decreased bleeding complications compared to patch due to the hemostatic advantage of native tissue. METHODS: A single-center retrospective comparative study of patients who underwent on-ECMO CDH repair between 2008 and 2022 was performed. RESULTS: Fifty-two patients met inclusion criteria: 18 patch (34.6%) and 34 flap (65.4%). There was no difference in CDH severity between groups. On univariate analysis, reoperation for surgical bleeding was lower following flap repair compared to patch (23.5% vs 55.6%, respectively; p = 0.045), 48-h postoperative blood product transfusion was lower after flap repair (132 mL/kg vs 273.5 mL/kg patch; p = 0.006), and two-year survival was increased in the flap repair group compared to patch (53.1% vs 17.7%, respectively; p = 0.036). On multivariate analysis adjusting for CDH side, day on ECMO repaired, and day of life CDH repaired, flap repair was significantly associated with lower five-day postoperative packed red blood cell transfusion amount, improved survival to hospital discharge, and improved two-year survival. CONCLUSIONS: Our experience suggests that the muscle flap technique for on-ECMO CDH repair is associated with reduced bleeding complications compared to prosthetic patch repair, which may in part be responsible for the improved survival seen in the flap repair group. These results support the flap repair technique as a favored method for on-ECMO CDH repair. LEVEL OF EVIDENCE: Level III.

Fetal lung volumes measured by MRI predict pulmonary morbidity among infants with giant omphaloceles.

OBJECTIVE: Giant omphaloceles (GO) have associated pulmonary hypoplasia and respiratory complications. Total lung volumes (TLV) on fetal MRI can prognosticate congenital diaphragmatic hernia outcomes; however, its applicability to GO is unknown. We hypothesize that late gestation TLV and observed-to-expected TLV (O/E TLV) on fetal MRI correlate with postnatal pulmonary morbidity in GO. METHOD: A single-institution retrospective review of GO evaluated between 2012 and 2022 was performed. Fetal MRI TLV between 32 and 36 weeks' gestation and O/E TLV throughout gestation were calculated and correlated with postnatal outcomes. RESULTS: 86 fetuses with omphaloceles were evaluated; however, only 26 met strict inclusion criteria. MRIs occurred between 18 and 36 weeks' gestation. Those requiring delivery room intubation had significantly lower late gestation TLV and O/E TLV. O/E TLV predicted tracheostomy placement and survival. Neither TLV nor O/E TLV predicted the length of hospitalization or supplemental oxygen after discharge. Three fetuses had a TLV less than 35 mL: one died of respiratory failure, and the other two required tracheostomy. CONCLUSIONS: Fetal MRI TLV measured between 32 and 36 weeks' gestation and O/E TLV predict the need for delivery room intubation and tracheostomy. O/E TLV correlated with survival. These data support fetal MRI as a prognostic tool to predict GO associated pulmonary morbidity.

Angiogenic and Inflammatory microRNA Regulation in a Mouse Model of Fetal Growth Restriction.

INTRODUCTION: Fetal growth restriction (FGR) is associated with impaired angiogenesis and chronic inflammation. MicroRNAs (miRs) are short noncoding RNAs that regulate gene expression at the post-transcriptional level by targeting messenger RNA (mRNA) for degradation or by suppressing translation. We hypothesize that dysregulation of miR-15b, an antiangiogenic miR, and miR-146a, an anti-inflammatory miR, are associated with the FGR's pathogenesis. METHODS: Pregnant mice were provided ad libitum access to food between E1 and E8. From E9-E18, dams received either a 50% caloric restricted diet (FGR) or continued ad libitum access (controls). Placentas were harvested at E18.5 and total RNA was extracted. Gene expression levels of miRs and mRNAs were compared between FGR and control placentas. RESULTS: Placentas affected by FGR demonstrated increased expression of miR-15b. Vascular endothelial growth factor alpha, which is downregulated in response to increased levels of miR-15b, was suppressed. The anti-inflammatory miR, miR-146a, was downregulated, resulting in upregulation of proinflammatory (IL-6, IL-8, and NFkB1) and oxidative stress (HIF-1α, SOD2, and Nox2) mediators. CONCLUSIONS: Aberrant angiogenesis and chronic inflammation seen in FGR appear to be associated with dysregulated miR-15b and miR-146a gene expression, respectively. This observation suggests these miRs play a post-transcriptional regulatory role in FGR, providing an insight into possible therapeutic targets.

CNP-miR146a Decreases Inflammation in Murine Acute Infectious Lung Injury.

Acute respiratory distress syndrome (ARDS) has approximately 40% in-hospital mortality, and treatment is limited to supportive care. Pneumonia is the underlying etiology in many cases with unrestrained inflammation central to the pathophysiology. We have previously shown that CNP-miR146a, a radical scavenging cerium oxide nanoparticle (CNP) conjugated to the anti-inflammatory microRNA(miR)-146a, reduces bleomycin- and endotoxin-induced acute lung injury (ALI) by decreasing inflammation. We therefore hypothesized that CNP-miR146a would decrease inflammation in murine infectious ALI. Mice were injured with intratracheal (IT) MRSA or saline followed by treatment with IT CNP-miR146a or saline control. Twenty-four hours post-infection, bronchoalveolar lavage fluid (BALF) and whole lungs were analyzed for various markers of inflammation. Compared to controls, MRSA infection significantly increased proinflammatory gene expression (IL-6, IL-8, TNFα, IL-1ß; p < 0.05), BALF proinflammatory cytokines (IL-6, IL-8, TNFα, IL-1ß; p < 0.01), and inflammatory cell infiltrate (p = 0.03). CNP-miR146a treatment significantly decreased proinflammatory gene expression (IL-6, IL-8, TNFα, IL-1ß; p < 0.05), bronchoalveolar proinflammatory protein leak (IL-6, IL-8, TNFα; p < 0.05), and inflammatory infiltrate (p = 0.01). CNP-miR146a decreases inflammation and improves alveolar-capillary barrier integrity in the MRSA-infected lung and has significant promise as a potential therapeutic for ARDS.

Triazolothiadiazine derivative positively modulates CXCR4 signaling and improves diabetic wound healing.

Development of specific therapies that target and accelerate diabetic wound repair is an urgent need to alleviate pain and suffering and the huge socioeconomic burden of this debilitating disease. C-X-C Motif Chemokine Ligand 12 (CXCL12) also know an stromal cell-derived factor 1α (SDF-1α) is a chemokine that binds the CXC chemokine receptor type 4 (CXCR4) and activates downstream signaling resulting in recruitment of hematopoietic cells to locations of tissue injury and promotes tissue repair. In diabetes, low expression of CXCL12 correlates with impaired wound healing. Activation of CXCR4 receptor signaling with agonists or positive allosteric modulators (PAMs) provides a potential for small molecule therapeutic discovery and development. We recently reported high throughput screening and identification of the CXCR4 partial agonist UCUF-728, characterization of in vitro activity and reduced wound closure time in diabetic mice at 100 µM as a proof-of-concept study. We report here, the discovery of a second chemical scaffold demonstrating increased agonist potency and represented by thiadiazine derivative, UCUF-965. UCUF-965 is a potent partial agonist of ß-arrestin recruitment in CXCR4 receptor overexpressing cell line. Furthermore, UCUF-965 potentiates the CXCL12 maximal response in cAMP signaling pathway, activates CXCL12 stimulated migration in lymphoblast cells and modulates the levels of specific microRNA involved in the complex wound repair process, specifically in mouse fibroblasts. Our results indicate that UCUF-965 acts as a PAM agonist of the CXCR4 receptor. Furthermore, UCUF-965 enhanced angiogenesis markers and reduced wound healing time by 36% at 10.0 µM in diabetic mice models compared to untreated control.

Immunomodulatory biomaterials on chemokine signaling in wound healing.

Normal wound healing occurs through a careful orchestration of cytokine and chemokine signaling in response to injury. Chemokines are a small family of chemotactic cytokines that are secreted by immune cells in response to injury and are primarily responsible for recruiting appropriate immune cell types to injured tissue at the appropriate time. Dysregulation of chemokine signaling is suspected to contribute to delayed wound healing and chronic wounds in diseased states. Various biomaterials are being used in the development of new therapeutics for wound healing and our understanding of their effects on chemokine signaling is limited. It has been shown that modifications to the physiochemical properties of biomaterials can affect the body's immune reaction. Studying these effects on chemokine expression by various tissues and cell type can help us develop novel biomaterial therapies. In this review, we summarize the current research available on both natural and synthetic biomaterials and their effects on chemokine signaling in wound healing. In our investigation, we conclude that our knowledge of chemokines is still limited and that many in fact share both pro-inflammatory and anti-inflammatory properties. The predominance of either a pro-inflammatory or anti-inflammatory profile is mostly likely dependent on timing after injury and exposure to the biomaterial. More research is needed to better understand the interaction and contribution of biomaterials to chemokine activity in wound healing and their immunomodulatory effects.

CNP-miR146a improves outcomes in a two-hit acute- and ventilator-induced lung injury model.

Acute respiratory distress syndrome (ARDS) has high mortality (~40 %) and requires the lifesaving intervention of mechanical ventilation. A variety of systemic inflammatory insults can progress to ARDS, and the inflamed and injured lung is susceptible to ventilator-induced lung injury (VILI). Strategies to mitigate the inflammatory response while restoring pulmonary function are limited, thus we sought to determine if treatment with CNP-miR146a, a conjugate of novel free radical scavenging cerium oxide nanoparticles (CNP) to the anti-inflammatory microRNA (miR)-146a, would protect murine lungs from acute lung injury (ALI) induced with intratracheal endotoxin and subsequent VILI. Lung injury severity and treatment efficacy were evaluated via lung mechanical function, relative gene expression of inflammatory biomarkers, and lung morphometry (stereology). CNP-miR146a reduced the severity of ALI and slowed the progression of VILI, evidenced by improvements in inflammatory biomarkers, atelectasis, gas volumes in the parenchymal airspaces, and the stiffness of the pulmonary system.

Effects of microRNAs on angiogenesis in diabetic wounds.

Diabetes mellitus is a morbid condition affecting a growing number of the world population, and approximately one third of diabetic patients are afflicted with diabetic foot ulcers (DFU), which are chronic non-healing wounds that frequently progress to require amputation. The treatments currently used for DFU focus on reducing pressure on the wound, staving off infection, and maintaining a moist environment, but the impaired wound healing that occurs in diabetes is a constant obstacle that must be faced. Aberrant angiogenesis is a major contributor to poor wound healing in diabetes and surgical intervention is often necessary to establish peripheral blood flow necessary for healing wounds. Over recent years, microRNAs (miRNAs) have been implicated in the dysregulation of angiogenesis in multiple pathologies including diabetes. This review explores the pathways of angiogenesis that become dysregulated in diabetes, focusing on miRNAs that have been identified and the mechanisms by which they affect angiogenesis.

Early outcomes of a myofascial repair technique for fetal myelomeningocele.

PURPOSE: Fetal repair of myelomeningocele (MMC) and myeloschisis leads to improved neurologic outcomes compared to postnatal repair, but the effects of modifications in closure techniques have not been extensively studied. Previous work has suggested that a watertight repair is requisite for improvement in hindbrain herniation (HBH) and to decrease postnatal hydrocephalus (HCP). Our institution adopted the myofascial closure technique for open fetal MMC repair in July 2019, which we hypothesized would result in decreased need for patch closure, improved HBH, and decreased rate of surgically-treated HCP. METHODS: A single-center retrospective study of patients who underwent fetal MMC or myeloschisis repair between March 2013 and February 2022 was performed. Outcomes were evaluated (n = 70 prior to July 2019, n = 34 after July 2019). Statistical significance was determined by Fisher's exact and Chi square tests (p < 0.05 significant). RESULTS: Patients who underwent myofascial closure were less likely to require a patch for skin closure (14.7% vs 58.6%, p < 0.0001). Myofascial closure was also associated with an increased rate of HBH improvement on two-week postoperative fetal MRI (93.9% vs 65.7%, p = 0.002). Surgically-treated HCP at one year was lower in the myofascial closure group (n = 21), however this did not reach statistical significance (23.8% vs 41.9%, p = 0.19). CONCLUSIONS: We conclude that the myofascial closure technique for repair of fetal MMC and myeloschisis is associated with significantly decreased need for patch closure and improvement in hindbrain herniation compared to our previous skin closure technique. These results support a surgical approach that employs a multilayer watertight closure.

Third-trimester percentage predicted lung volume and percentage liver herniation as prognostic indicators in congenital diaphragmatic hernia.

BACKGROUND: Over the last two decades, fetal imaging has greatly improved, and new prenatal imaging measurements have been developed to characterize congenital diaphragmatic hernia (CDH) severity. OBJECTIVE: To determine the best prenatal imaging predictor of postnatal CDH outcomes, including use of extracorporeal membrane oxygenation (ECMO) and in-hospital mortality, with particular attention to the percentage of liver herniation (%LH) as a predictor. Additionally, we sought to guide best practices across hospital systems including improved models of prenatal risk assessment. MATERIALS AND METHODS: We conducted a retrospective review of infants with left CDH who were prenatally diagnosed. We analyzed prenatal imaging measurements including observed-to-expected (O/E) lung-to-head ratio (LHR) on US, percentage predicted lung volume (PPLV) on MRI, and O/E total fetal lung volume (TFLV) and %LH on MRI. We compared prenatal imaging characteristics for infants with (1) in-hospital postnatal mortality and (2) use of ECMO. Then we performed multivariate logistic regression to determine independent predictors of postnatal outcomes. RESULTS: We included 63 infants with a median gestation of 34 weeks at the time of prenatal MRI. Low O/E LHR (31.2 vs. 50, P < 0.0001), PPLV (14.7 vs. 22.6, P < 0.0001) and O/E TLFV (24.6 vs. 38.3, P < 0.0001) and high %LH (15.1 vs. 2.1, P = 0.0006) were associated with worse postnatal outcomes; however, only PPLV was predictive of survival and need for ECMO on multivariable analysis. PPLV survival to discharge model showed an area under the curve (AUC) of 0.93 (95% confidence interval [CI]: 0.86, 0.99), P < 0.0001; and an odds ratio of 68.7 (95% CI: 6.5-2,302), P = 0.003. PPLV need for ECMO model showed AUC = 0.87 (95% CI: 0.78, 0.96), P < 0.0001; and odds ratio = 20.1 (95% CI: 3.1-226.3), P = 0.011. CONCLUSION: Low O/E LHR, PPLV and O/E TFLV and high %LH in the third trimester are associated with worse postnatal outcomes. PPLV most strongly predicted outcome using a logistic regression model. Percentage of liver herniation was not an independent predictor of outcomes.

Engineered Faceted Cerium Oxide Nanoparticles for Therapeutic miRNA Delivery.

In general, wound healing is a highly ordered process, with distinct phases of inflammation, proliferation, and remodeling. However, among diabetic patients, the progression through these phases is often impeded by increased level of oxidative stress and persistent inflammation. Our previous studies demonstrated that cerium oxide nanoparticles (CNPs) conjugated with therapeutic microRNA146a (miR146a) could effectively enhance wound healing by targeting the NFκB pathway, reducing oxidative stress and inflammation. In the present study, we consider the potential effects of nanomaterial surface-faceting and morphology on the efficacy of miRNA delivery. Compared with octahedral-CNPs and cubic-CNPs, rod-CNPs exhibited higher loading capacity. In addition, in comparing the influence of particle morphology on wound healing efficacy, several markers for bioactivity were evaluated and ascribed to the combined effects of the gene delivery and reactive oxygen species (ROS) scavenging properties. In the cellular treatment study, rod-CNP-miR146a displayed the greatest miR146a delivery into cells. However, the reduction of IL-6 was only observed in the octahedral-CNP-miR146a, suggesting that the efficacy of the miRNA delivery is a result of the combination of various factors. Overall, our results give enlightenments into the relative delivery efficiency of the CNPs with different morphology enhancing miRNA delivery efficacy.

Understanding the Care Journey and Needs of Advanced Fetal Care Center Patients.

Introduction This study describes the parental perspective of the management and care experience of patients experiencing a pregnancy complicated by a fetal diagnosis to inform more supportive patient-centered care. Methods We conducted a prospective multicenter qualitative patient experience study at three metropolitan children's hospitals' advanced fetal care centers: the Cincinnati, Colorado, and Midwest Fetal Care Centers. Data were collected from pregnant patients who experienced the management of a pregnancy complicated by a fetal anomaly. Clinical journey data were obtained using qualitative research methods in post-birth semistructured interviews. We assembled a generalizable patient journey map to identify the general clinical encounters, and present common participant experiences from diagnosis to post-birth discharge. Results Fifteen families were interviewed; four experienced a loss (27%). Common experiences of trust, education, surrounding support, consistency, and abandonment emerged across all centers. Participant trust in their care team was gained through strong referrals, institutional reputation, and transparent outcomes. Unconditional care team support and continual reassurance was paramount to maintaining participant trust throughout their care journey. Participants appreciated both active and passive educational techniques at clinical touch points. A consistent point of contact assured participants. All families mentioned they felt close to their fetal care team; however, several mentioned that the post-birth transition of care created feelings of abandonment. Conclusions When a family understands the clinical information and feels supported, they are empowered and confident in their ability to navigate their circumstances. Listening to the parental perspective is important to delivering sensitive fetal care.

Improved survival for infants with severe congenital diaphragmatic hernia.

BACKGROUND: Survival for severe (observed to expected lung-head ratio (O:E LHR) < 25%) congenital diaphragmatic hernia (CDH) remains a challenge (15-25%). Management strategies have focused on fetal endoscopic tracheal occlusion (FETO) and/or extracorporeal membrane oxygenation therapy (ECMO) utilization. OBJECTIVE(S): Describe single center outcomes for infants with severe CDH. STUDY DESIGN: Observational study of 13 severe CDH infants managed with ECMO, a protocolized DR algorithm, and early repair on ECMO with an innovative perioperative anticoagulation strategy. RESULTS: 13/140 (9.3%) infants met criteria and were managed with ECMO. 77% survived ECMO and 69% survived to discharge. 22% underwent tracheostomy. Median days on mechanical ventilation was 39 days (IQR 22:107.5) and length of stay 135 days (IQR 62.5:211.5). All infants received a gastrostomy tube (GT) and were discharged home on oxygen and pulmonary hypertension (PH) meds. CONCLUSION: Survival for infants with severe CDH can be optimized with early aggressive intervention and protocolized algorithms (149).

Silk Fibroin-Based Therapeutics for Impaired Wound Healing.

Impaired wound healing can lead to local hypoxia or tissue necrosis and ultimately result in amputation or even death. Various factors can influence the wound healing environment, including bacterial or fungal infections, different disease states, desiccation, edema, and even systemic viral infections such as COVID-19. Silk fibroin, the fibrous structural-protein component in silk, has emerged as a promising treatment for these impaired processes by promoting functional tissue regeneration. Silk fibroin's dynamic properties allow for customizable nanoarchitectures, which can be tailored for effectively treating several wound healing impairments. Different forms of silk fibroin include nanoparticles, biosensors, tissue scaffolds, wound dressings, and novel drug-delivery systems. Silk fibroin can be combined with other biomaterials, such as chitosan or microRNA-bound cerium oxide nanoparticles (CNP), to have a synergistic effect on improving impaired wound healing. This review focuses on the different applications of silk-fibroin-based nanotechnology in improving the wound healing process; here we discuss silk fibroin as a tissue scaffold, topical solution, biosensor, and nanoparticle.

Photopolymerized Zwitterionic Hydrogels with a Sustained Delivery of Cerium Oxide Nanoparticle-miR146a Conjugate Accelerate Diabetic Wound Healing.

In the United States, $87 billion per year is spent on the care of diabetic ulcers alone. Although the pathophysiology of diabetic wound healing is multifaceted, high systemic levels of inflammation and increased reactive oxygen species are often implicated in the wound healing impairment. Zwitterionic materials have been demonstrated to reduce inflammation and increase extracellular matrix deposition in wound beds, and here, we demonstrate a fabrication method for photopolymerized zwitterionic hydrogels that also enables sustained drug delivery over time. A therapeutic molecule of interest that is examined in this work is cerium oxide nanoparticle tagged with microRNA-146a (CNP-miR146a) to combat both oxidative stress and inflammation. The hydrogels are composed of zwitterionic and nonzwitterionic monomers, and the hydrogel formation occurs in the absence of a crosslinker. The hydrogels exhibit a wide range of stiffness and mechanical properties depending on their monomer content. Additionally, these hydrogels exhibit sustained release of nanoparticles and proteins. Finally, when employed in an in vivo diabetic mouse wound healing model, the zwitterionic hydrogels alone and laden with the CNP-miR146a conjugate significantly improved the rate of diabetic wound healing. Overall, these materials have excellent potential to be used as a topical treatment for chronic diabetic wounds.

Discovery of Small Molecule Activators of Chemokine Receptor CXCR4 That Improve Diabetic Wound Healing.

Diabetes produces a chronic inflammatory state that contributes to the development of vascular disease and impaired wound healing. Despite the known individual and societal impacts of diabetic ulcers, there are limited therapies effective at improving healing. Stromal cell-derived factor 1α (SDF-1α) is a CXC chemokine that functions via activation of the CXC chemokine receptor type 4 (CXCR4) receptor to recruit hematopoietic cells to locations of tissue injury and promote tissue repair. The expression of SDF-1α is reduced in diabetic wounds, suggesting a potential contribution to wound healing impairment and presenting the CXCR4 receptor as a target for therapeutic investigations. We developed a high-throughput ß-arrestin recruitment assay and conducted structure-activity relationship (SAR) studies to screen compounds for utility as CXCR4 agonists. We identified CXCR4 agonist UCUF-728 from our studies and further validated its activity in vitro in diabetic fibroblasts. UCUF-728 reduced overexpression of miRNA-15b and miRNA-29a, negative regulators of angiogenesis and type I collagen production, respectively, in diabetic fibroblasts. In vivo, UCUF-728 reduced the wound closure time by 36% and increased the evidence of angiogenesis in diabetic mice. Together, this work demonstrates the clinical potential of small molecule CXCR4 agonists as novel therapies for pathologic wound healing in diabetes.