Dysregulation of Connexin Expression Plays a Pivotal Role in Psoriasis.

BACKGROUND: Psoriasis, a chronic inflammatory disease affecting 2-3% of the population, is characterised by epidermal hyperplasia, a sustained pro-inflammatory immune response and is primarily a T-cell driven disease. Previous work determined that Connexin26 is upregulated in psoriatic tissue. This study extends these findings. METHODS: Biopsies spanning psoriatic plaque (PP) and non-involved tissue (PN) were compared to normal controls (NN). RNA was isolated and subject to real-time PCR to determine gene expression profiles, including GJB2/CX26, GJB6/CX30 and GJA1/CX43. Protein expression was assessed by immunohistochemistry. Keratinocytes and fibroblasts were isolated and used in 3D organotypic models. The pro-inflammatory status of fibroblasts and 3D cultures was assessed via ELISA and RnD cytokine arrays in the presence or absence of the connexin channel blocker Gap27. RESULTS: Connexin26 expression is dramatically enhanced at both transcriptional and translational level in PP and PN tissue compared to NN (>100x). In contrast, CX43 gene expression is not affected, but the protein is post-translationally modified and accumulates in psoriatic tissue. Fibroblasts isolated from psoriatic patients had a higher inflammatory index than normal fibroblasts and drove normal keratinocytes to adopt a "psoriatic phenotype" in a 3D-organotypic model. Exposure of normal fibroblasts to the pro-inflammatory mediator peptidoglycan, isolated from Staphylococcus aureus enhanced cytokine release, an event protected by Gap27. CONCLUSION: dysregulation of the connexin26:43 expression profile in psoriatic tissue contributes to an imbalance of cellular events. Inhibition of connexin signalling reduces pro-inflammatory events and may hold therapeutic benefit.

Connexin 26 and 43 play a role in regulating proinflammatory events in the epidermis.

Dysregulation of Connexin (CX) expression and function is associated with a range of chronic inflammatory conditions including psoriasis and nonhealing wounds. To mimic a proinflammatory environment, HaCaT cells, a model human keratinocyte cell line, were challenged with 10 µg/ml peptidoglycan (PGN) isolated from Staphylococcus aureus for 15 min to 24 hr in the presence or absence of CX blockers and/or following CX26, CX43, PANX1 and TLR2 small interfering RNA (siRNA) knockdown (KD). Expression levels of IL-6, IL-8, CX26, CX43, PANX1, TLR2 and Ki67 were assessed by quantitative real-time polymerase chain reaction, western blot analysis and/or immunocytochemistry. Nuclear factor kappa ß (NF-κß) was blocked with BAY 11-7082, CX-channel function was determined by adenosine 5'-triphosphate (ATP) release assays. Enzyme-linked immunosorbent assay monitored IL6 release following PGN challenge in the presence or absence of siRNA or blockers of CX or purinergic signalling. Exposure to PGN induced IL-6, IL-8, CX26 and TLR2 gene expression but it did not influence CX43, PANX1 or Ki67 messenger RNA expression levels. CX43 protein levels were reduced following 24 hr PGN exposure. PGN-induced CX26 and IL-6 expression were also aborted by TLR2-KD and inhibition of NF-κß. ATP and IL-6 release were stimulated following 15 min and 1-24 hr challenge with PGN, respectively. Release of both agents was inhibited by coincubation with CX-channel blockers, CX26-, CX43- and TLR2-KD. The IL-6 response was also reduced by purinergic blockers. CX-signalling plays a role in the innate immune response in the epidermis. PGN is detected by TLR2, which via NF-κß, directly activates CX26 and IL-6 expression. CX43 and CX26 maintain proinflammatory signalling by permitting ATP release, however, PANX1 does not participate.

The potential of human induced pluripotent stem cells for modelling diabetic wound healing in vitro.

Impaired wound healing and ulceration caused by diabetes mellitus, is a significant healthcare burden, markedly impairs quality of life for patients, and is the major cause of amputation worldwide. Current experimental approaches used to investigate the complex wound healing process often involve cultures of fibroblasts and/or keratinocytes in vitro, which can be limited in terms of complexity and capacity, or utilisation of rodent models in which the mechanisms of wound repair differ substantively from that in humans. However, advances in tissue engineering, and the discovery of strategies to reprogramme adult somatic cells to pluripotency, has led to the possibility of developing models of human skin on a large scale. Generation of induced pluripotent stem cells (iPSCs) from tissues donated by diabetic patients allows the (epi)genetic background of this disease to be studied, and the ability to differentiate iPSCs to multiple cell types found within skin may facilitate the development of more complex skin models; these advances offer key opportunities for improving modelling of wound healing in diabetes, and the development of effective therapeutics for treatment of chronic wounds.

Connexin Communication Compartments and Wound Repair in Epithelial Tissue.

Epithelial tissues line the lumen of tracts and ducts connecting to the external environment. They are critical in forming an interface between the internal and external environment and, following assault from environmental factors and pathogens, they must rapidly repair to maintain cellular homeostasis. These tissue networks, that range from a single cell layer, such as in airway epithelium, to highly stratified and differentiated epithelial surfaces, such as the epidermis, are held together by a junctional nexus of proteins including adherens, tight and gap junctions, often forming unique and localised communication compartments activated for localised tissue repair. This review focuses on the dynamic changes that occur in connexins, the constituent proteins of the intercellular gap junction channel, during wound-healing processes and in localised inflammation, with an emphasis on the lung and skin. Current developments in targeting connexins as corrective therapies to improve wound closure and resolve localised inflammation are also discussed. Finally, we consider the emergence of the zebrafish as a concerted whole-animal model to study, visualise and track the events of wound repair and regeneration in real-time living model systems.

The Connexin Mimetic Peptide Gap27 and Cx43-Knockdown Reveal Differential Roles for Connexin43 in Wound Closure Events in Skin Model Systems.

In the epidermis, remodelling of Connexin43 is a key event in wound closure. However, controversy between the role of connexin channel and non-channel functions exist. We compared the impact of SiRNA targeted to Connexin43 and the connexin mimetic peptide Gap27 on scrape wound closure rates and hemichannel signalling in adult keratinocytes (AK) and fibroblasts sourced from juvenile foreskin (JFF), human neonatal fibroblasts (HNDF) and adult dermal tissue (ADF). The impact of these agents, following 24 h exposure, on GJA1 (encoding Connexin43), Ki67 and TGF-ß1 gene expression, and Connexin43 and pSmad3 protein expression levels, were examined by qPCR and Western Blot respectively. In all cell types Gap27 (100-100 µM) attenuated hemichannel activity. In AK and JFF cells, Gap27 (100 nM-100 µM) enhanced scrape wound closure rates by ~50% but did not influence movement in HNDF or ADF cells. In both JF and AK cells, exposure to Gap27 for 24 h reduced the level of Cx43 protein expression but did not affect the level in ADF and HNDF cells. Connexin43-SiRNA enhanced scrape wound closure in all the cell types under investigation. In HDNF and ADF, Connexin43-SiRNA enhanced cell proliferation rates, with enhanced proliferation also observed following exposure of HDNF to Gap27. By contrast, in JFF and AK cells no changes in proliferation occurred. In JFF cells, Connexin43-SiRNA enhanced TGF-ß1 levels and in JFF and ADF cells both Connexin43-SiRNA and Gap27 enhanced pSmad3 protein expression levels. We conclude that Connexin43 signalling plays an important role in cell migration in keratinocytes and foreskin derived fibroblasts, however, different pathways are evoked and in dermal derived adult and neonatal fibroblasts, inhibition of Connexin43 signalling plays a more significant role in regulating cell proliferation than cell migration.

Community-acquired pneumonia in the post 13-valent pneumococcal conjugate vaccine era.

PURPOSE OF REVIEW: This review covers the outpatient management of pediatric community-acquired pneumonia (CAP), discussing the changing microbiology of CAP since the introduction of the 13-valent pneumococcal conjugate vaccine in 2010, and providing an overview of national guideline recommendations for diagnostic evaluation and treatment. RECENT FINDINGS: Rates of invasive pneumococcal disease and pneumococcal antibiotic resistance have plummeted since widespread 13-valent pneumococcal conjugate vaccine immunization. Viruses remain the most common cause of CAP in young children; children over age 5 years have increased rates of Mycoplasma pneumoniae. A recent national guideline offers recommendations for office-based diagnostic evaluation and treatment of pediatric CAP. SUMMARY: This review offers a discussion of the above findings with practical recommendations for the office-based practitioner in the evaluation and treatment of an infant (>3 months) or child with suspected CAP.

Inappropriate Use of Peripherally Inserted Central Catheters in Pediatrics: A Multisite Study.

OBJECTIVES: This study aimed to describe how the current practice of peripherally inserted central catheter (PICC) use in hospitalized children aligns with the Michigan Appropriateness Guide for Intravenous Catheters (miniMAGIC) in Children recommendations, explore variation across sites, and describe the population of children who do not receive appropriate PICCs. METHODS: A retrospective study was conducted at 4 children's hospitals in the United States. Children with PICCs placed January 2019 to December 2021 were included. Patients in the NICU were excluded. PICCs were categorized using the miniMAGIC in Children classification as inappropriate, uncertain appropriateness and appropriate. RESULTS: Of the 6051 PICCs identified, 9% (n = 550) were categorized as inappropriate, 9% (n = 550) as uncertain appropriateness, and 82% (n = 4951) as appropriate. The number of PICCs trended down over time, but up to 20% of PICCs each year were not appropriate, with significant variation between sites. Within inappropriate or uncertain appropriateness PICCs (n = 1100 PICC in 1079 children), median (interquartile range) patient age was 4 (0-11) years, 54% were male, and the main reason for PICC placement was prolonged antibiotic course (56%, n = 611). The most common admitting services requesting the inappropriate/uncertain appropriateness PICCs were critical care 24%, general pediatrics 22%, and pulmonary 20%. Complications resulting in PICC removal were identified in 6% (n = 70) of inappropriate/uncertain PICCs. The most common complications were dislodgement (3%) and occlusion (2%), with infection and thrombosis rates of 1% (n = 10 and n = 13, respectively). CONCLUSIONS: Although the majority of PICCs met appropriateness criteria, a substantial proportion of PICCs were deemed inappropriate or of uncertain appropriateness, illustrating an opportunity for quality improvement.

Guideline for the prevention of acute nausea and vomiting due to antineoplastic medication in pediatric cancer patients.

This guideline provides an approach to the prevention of acute antineoplastic-induced nausea and vomiting (AINV) in children. It was developed by an international, inter-professional panel using AGREE and CAN-IMPLEMENT methods. Evidence-based interventions that provide optimal AINV control in children receiving antineoplastic agents of high, moderate, low, and minimal emetogenicity are recommended. Recommendations are also made regarding selection of antiemetic agents for children who are unable to receive corticosteroids for AINV control, the role of aprepitant and optimal doses of antiemetic agents. Gaps in the evidence used to support the recommendations were identified. The contribution of this guideline to AINV control in children requires prospective evaluation.

Clinical guideline highlights for the hospitalist: Evaluation and management of well-appearing febrile infants 8 to 60 days old.

GUIDELINE TITLE: Evaluation and Management of Well-Appearing Febrile Infants 8 to 60 Days Old RELEASE DATE: August 1, 2021 PRIOR VERSION(S): n/a DEVELOPER: American Academy of Pediatrics FUNDING SOURCE: American Academy of Pediatrics TARGET POPULATION: Well-appearing, otherwise healthy infants with fever, ages 8 to 60 days, excluding those with prematurity (<37 wk gestation), focal bacterial infections except acute otitis media, high suspicion for herpes simplex virus (vesicles), clinical bronchiolitis.

Gender Distribution of Scholarship and Measures of National Recognition in Hospital Medicine.

OBJECTIVE: Our specific aim was to assess the gender distribution of aspects of scholarly productivity and professional standing for pediatric hospital medicine over a 5-year period. We also evaluated for correlation between the makeup of editorial boards, conference planning committees, and chosen content. METHODS: We reviewed scholarly publications, presentations, editorial boards, planning committees, awardees, and society leadership in pediatric hospital medicine from 2015 to 2019 and determined gender using published methods to assess for differences between observed proportions of women authors and presenters and the proportion of women in the field. RESULTS: The field of pediatric hospital medicine at large is 69% women (95% confidence internal [CI] 68%-71%), and an estimated 57% of senior members are women (95% CI 54%-60%). We evaluated 570 original science manuscripts and found 67% (95% CI 63%-71%) women first authors and 49% (95% CI 44%-53%) women senior authors. We evaluated 1093 presentations at national conferences and found 69% (95% CI 65%-72%) women presenters of submitted content and 44% (95% CI 37%-51%) women presenters of invited content. Senior authorship and invited speaking engagements demonstrated disproportionately low representation of women when compared with senior members of the field (senior authorship, P = .002; invited presenters, P < .001). Strong positive correlation between gender composition of conference planning committees and selected content was also noted (r = 0.94). CONCLUSION: Our study demonstrated representative gender distribution for some aspects of scholarly productivity in pediatric hospital medicine; however, a lack of gender parity exists in senior roles.

Long peripheral catheters in children: A scoping review.

BACKGROUND AND OBJECTIVES: Long peripheral catheters (LPCs) are emerging vascular access devices used for short-medium term vascular access needs. Literature in adults suggests LPCs have longer dwell-times than peripheral intravenous catheters (PIVs) and lower rates of serious complications than peripherally inserted central catheters (PICCs). The role of LPCs in children is less established. The objective of this scoping review is to describe and synthesize the existing literature on the effectiveness and safety of LPCs in children. METHODS: This review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. Searches were done in MEDLINE (Ovid), Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science Core Collection, Scopus, CINAHL (Ebsco), and Google Scholar most recently on February 22, 2022. Studies were included if published in English on or after 2000 and included patients <18 years of age. RESULTS: Twenty-one studies were included. The body of literature is variable in quality, measurements, and reported outcomes. Median dwell-time ranged from 5 to 14 days. The rate of completion of therapy ranged from 20% to 86%. Dislodgement, occlusion, and infiltration were the most common complications reported (0%-31%). Venous thromboembolism rates ranged from 0% to 13%. The rate of catheter-related bloodstream infection was 0% in 9 of 10 studies. Less than 50% of studies reported comparative outcomes. CONCLUSION: LPCs show promising outcomes in select populations, with longer dwell-time than PIVs and possibly lower rates of serious complications than PICCs. However, more research is needed to clarify the optimal use of LPCs in pediatrics.

The 2021 Pediatric Hospital Medicine Workforce: Results of a National Survey of Program Leaders.

OBJECTIVE: Pediatric Hospital Medicine (PHM) is a young subspecialty with practice models that continue to evolve. To inform program and workforce planning, it is essential to understand the current state. This study sought to delineate current work models for PHM. METHODS: In the spring of 2021, we conducted a survey-based cohort study of individuals identifying as PHM program leaders. Individuals were invited based on membership in the 3 PHM sponsoring societies. Additional respondents were recruited through society listservs. RESULTS: One hundred ninety-eight program leaders responded to the program model survey. One-half covered only community sites, 21.2% covered only university sites, and 21.2% covered both university and community sites. Programs provided a diverse set of services, with community sites covering more services, including newborn nurseries, emergency department consultation, and delivery room care. Median total hours for 1.0 clinical full time equivalent were 1849 across all sites, 1800 at university-only sites, and 1900 at community-only sites. Inpatient floor patient caps, when present, were higher for resident covered versus noncovered teams (16 vs 13). Similarly, back-up activation was higher for resident-covered teams (15-16) than noncovered teams (12-13.5). CONCLUSIONS: Current data on clinical work hours for pediatric hospitalists are consistent with recent, smaller studies, suggesting that the current national median for a 1.0 FTE clinical position at university-based sites is 1800 annual hours. Community hospitalists often work more clinical hours than university sites and more commonly provide a broader range of service lines. More studies are needed to explore the differences between community and university site work models.

Gender Distribution in Pediatric Hospital Medicine Leadership.

Pediatric Hospital Medicine (PHM), a field early in its development and with a robust pipeline of women, is in a unique position to lead the way in gender equity. We describe the proportion of women in divisional and fellowship leadership positions at university-based PHM programs (n = 142). When compared with the PHM field at large, women appear to be underrepresented as PHM division/program leaders (70% vs 55%; P< .001) but not as fellowship directors (70% vs 66%; P > .05). Women appear proportionally represented in associate/assistant leadership roles when compared with the distribution of the PHM field at large. Tracking these trends overtime is essential to advancing the field.

Connexins and the Epithelial Tissue Barrier: A Focus on Connexin 26.

Epithelial tissue responds rapidly to environmental triggers and is constantly renewed. This tissue is also highly accessible for therapeutic targeting. This review highlights the role of connexin mediated communication in avascular epithelial tissue. These proteins form communication conduits with the extracellular space (hemichannels) and between neighboring cells (gap junctions). Regulated exchange of small metabolites less than 1kDa aide the co-ordination of cellular activities and in spatial communication compartments segregating tissue networks. Dysregulation of connexin expression and function has profound impact on physiological processes in epithelial tissue including wound healing. Connexin 26, one of the smallest connexins, is expressed in diverse epithelial tissue and mutations in this protein are associated with hearing loss, skin and eye conditions of differing severity. The functional consequences of dysregulated connexin activity is discussed and the development of connexin targeted therapeutic strategies highlighted.

Frog nest foams exhibit pharmaceutical foam-like properties.

Foams have frequently been used as systems for the delivery of cosmetic and therapeutic molecules; however, there is high variability in the foamability and long-term stability of synthetic foams. The development of pharmaceutical foams that exhibit desirable foaming properties, delivering appropriate amounts of the active pharmaceutical ingredient (API) and that have excellent biocompatibility is of great interest. The production of stable foams is rare in the natural world; however, certain species of frogs have adopted foam production as a means of providing a protective environment for their eggs and larvae from predators and parasites, to prevent desiccation, to control gaseous exchange, to buffer temperature extremes, and to reduce UV damage. These foams show great stability (up to 10 days in tropical environments) and are highly biocompatible due to the sensitive nature of amphibian skin. This work demonstrates for the first time that nests of the túngara frog (Engystomops pustulosus) are stable ex situ with useful physiochemical and biocompatible properties and are capable of encapsulating a range of compounds, including antibiotics. These protein foam mixtures share some properties with pharmaceutical foams and may find utility in a range of pharmaceutical applications such as topical drug delivery systems.

The Michigan Appropriateness Guide for Intravenous Catheters in Pediatrics: miniMAGIC.

OBJECTIVES: Vascular access device decision-making for pediatric patients remains a complex, highly variable process. To date, evidence-based criteria to inform these choices do not exist. The objective of the Michigan Appropriateness Guide for Intravenous Catheters in pediatrics (miniMAGIC) was to provide guidance on device selection, device characteristics, and insertion technique for clinicians, balancing and contextualizing evidence with current practice through a multidisciplinary panel of experts. METHODS: The RAND Corporation and University of California, Los Angeles Appropriateness Method was used to develop miniMAGIC, which included the following sequential phases: definition of scope and key terms, information synthesis and literature review, expert multidisciplinary panel selection and engagement, case scenario development, and appropriateness ratings by an expert panel via 2 rounds. RESULTS: The appropriateness of the selection, characteristics, and insertion technique of intravenous catheters commonly used in pediatric health care across age populations (neonates, infants, children, and adolescents), settings, diagnoses, clinical indications, insertion locations, and vessel visualization devices and techniques was defined. Core concepts including vessel preservation, insertion and postinsertion harm minimization (eg, infection, thrombosis), undisrupted treatment provision, and inclusion of patient preferences were emphasized. CONCLUSIONS: In this study, we provide evidence-based criteria for intravenous catheter selection (from umbilical catheters to totally implanted venous devices) in pediatric patients across a range of clinical indications. miniMAGIC also highlights core vascular access practices in need of collaborative research and innovation.

Clinical Guideline Highlights for the Hospitalist: Maintenance Intravenous Fluids in Infants and Children.

GUIDELINE TITLE: 2018 American Academy of Pediatrics (AAP) Clinical Practice Guideline: Maintenance Intravenous Fluids in Children RELEASE DATE: November 26, 2018 PRIOR VERSION: Not Applicable DEVELOPER: Multidisciplinary subcommittee of experts assembled by the AAP FUNDING SOURCE: AAP TARGET POPULATION: Patients 28 days to 18 years of age requiring maintenance intravenous fluids (IVFs).