ABSTRACT
STUDY OBJECTIVE: Boarding admitted patients in emergency departments (EDs) is a national crisis that is worsening despite potential financial disadvantages. The objective of this study was to assess costs associated with boarding. METHODS: We conducted a prospective, observational investigation of patients admitted through an ED for management of acute stroke at a large, urban, academic, comprehensive stroke center hospital. We employed time-driven activity-based costing methodology to estimate cost for patient care activities during admission and aggregated results to estimate the total cost of boarding versus inpatient care. Primary outcomes were total daily costs per patient for medical-surgical (med/surg) boarding, med/surg inpatient care, ICU boarding, and ICU inpatient care. RESULTS: The total daily cost per patient with acute stroke was US$1856, for med/surg boarding versus US$993 for med/surg inpatient care and US$2267, for ICU boarding versus US$2165, for ICU inpatient care. These differences were even greater when accounting for costs associated with traveler nurses. ED nurses spent 293 min/d (mean) caring for each med/surg boarder; inpatient nurses spent 313 min/d for each med/surg inpatient. ED nurses spent 419 min/d caring for each ICU boarder; inpatient nurses spent 787 min/d for each ICU inpatient. Neurology attendings and residents spent 25 and 52 min/d caring for each med/surg boarder versus 62 minutes and 90 minutes for each med/surg inpatient, respectively. CONCLUSION: Using advanced cost-accounting methods, our investigation provides novel evidence that boarding of admitted patients is financially costly, adding greater urgency for elimination of this practice.
ABSTRACT
The continued emergence of Neisseria gonorrhoeae strains that express resistance to multiple antibiotics, including the last drug for empiric monotherapy (ceftriaxone), necessitates the development of new treatment options to cure gonorrheal infections. Toward this goal, we recently reported that corallopyronin A (CorA), which targets the switch region of the ß' subunit (RpoC) of bacterial DNA-dependent RNA polymerase (RNAP), has potent anti-gonococcal activity against a panel of multidrug-resistant clinical strains. Moreover, in that study, CorA could eliminate gonococcal infection of primary human epithelial cells and gonococci in a biofilm state. To determine if N. gonorrhoeae could develop high-level resistance to CorA in a single step, we sought to isolate spontaneous mutants expressing any CorA resistance phenotypes. However, no single-step mutants with high-level CorA resistance were isolated. High-level CorA resistance could only be achieved in this study through a multi-step pathway involving over-expression of the MtrCDE drug efflux pump and single amino acid changes in the ß and ß' subunits (RpoB and RpoC, respectively) of RNAP. Molecular modeling of RpoB and RpoC interacting with CorA was used to deduce how the amino acid changes in RpoB and RpoC could influence gonococcal resistance to CorA. Bioinformatic analyses of whole genome sequences of clinical gonococcal isolates indicated that the CorA resistance determining mutations in RpoB/C, identified herein, are very rare (≤ 0.0029%), suggesting that the proposed pathway for resistance is predictive of how this phenotype could potentially evolve if CorA is used therapeutically to treat gonorrhea in the future. IMPORTANCE: The continued emergence of multi-antibiotic-resistant strains of Neisseria gonorrhoeae necessitates the development of new antibiotics that are effective against this human pathogen. We previously described that the RNA polymerase-targeting antibiotic corallopyronin A (CorA) has potent activity against a large collection of clinical strains that express different antibiotic resistance phenotypes including when such gonococci are in a biofilm state. Herein, we tested whether a CorA-sensitive gonococcal strain could develop spontaneous resistance. Our finding that CorA resistance could only be achieved by a multi-step process involving over-expression of the MtrCDE efflux pump and single amino acid changes in RpoB and RpoC suggests that such resistance may be difficult for gonococci to evolve if this antibiotic is used in the future to treat gonorrheal infections that are refractory to cure by other antibiotics.
Subject(s)
Anti-Bacterial Agents , Bacterial Proteins , DNA-Directed RNA Polymerases , Gonorrhea , Microbial Sensitivity Tests , Neisseria gonorrhoeae , Neisseria gonorrhoeae/drug effects , Neisseria gonorrhoeae/genetics , Neisseria gonorrhoeae/enzymology , DNA-Directed RNA Polymerases/genetics , DNA-Directed RNA Polymerases/metabolism , Anti-Bacterial Agents/pharmacology , Humans , Gonorrhea/microbiology , Gonorrhea/drug therapy , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Drug Resistance, Bacterial/genetics , Mutation , Drug Resistance, Multiple, Bacterial/genetics , Biofilms/drug effects , Biofilms/growth & development , LactonesABSTRACT
BACKGROUND: The end of 2019 marked the emergence of the COVID-19 pandemic. Public avoidance of health care facilities, including the emergency department (ED), has been noted during prior pandemics. OBJECTIVE: This study described pandemic-related changes in adult and pediatric ED presentations, acuity, and hospitalization rates during the pandemic in a major metropolitan area. METHODS: The study was a cross-sectional analysis of ED visits occurring before and during the pandemic. Sites collected daily ED patient census; monthly ED patient acuity, as the Emergency Severity Index (ESI) score; and disposition. Prepandemic ED visits occurring from January 1, 2019 through December 31, 2019 were compared with ED visits occurring during the pandemic from January 1, 2020 through March 31, 2021. The change in prepandemic and pandemic ED volume was found using 7-day moving average of proportions. RESULTS: The study enrolled 83.8% of the total ED encounters. Pandemic adult and pediatric visit volume decreased to as low as 44.7% (95% CI 43.1-46.3%; p < 0.001) and 22.1% (95% CI 19.3-26.0%; p < 0.001), respectively, of prepandemic volumes. There was also a relative increase in adult and pediatric acuity (ESI level 1-3) and the admission percentage for adult (20.3% vs. 22.9%; p < 0.01) and pediatric (5.1% vs. 5.6%; p < 0.01) populations. CONCLUSIONS: Total adult and pediatric encounters were reduced significantly across a major metropolitan area. Patient acuity and hospitalization rates were relatively increased. The development of strategies for predicting ED avoidance will be important in future pandemics.
Subject(s)
COVID-19 , Adult , Humans , Child , COVID-19/epidemiology , Pandemics , Cross-Sectional Studies , Retrospective Studies , Emergency Service, HospitalABSTRACT
BACKGROUND: Whilst there has been significant improvement in mortality outcomes after emergency laparotomy, there is little information on longer term outcomes in the year after discharge. The main aim of the study was to assess the impact that an emergency laparotomy has on patients' and employment and health status 1 year after surgery. METHODS: This study was a questionnaire study conducted in a single centre district general hospital of patients who had undergone an emergency laparotomy between October 2015 and December 2016. Patients were included according to the National Emergency Laparotomy Audit criteria. At screening, patients who were alive at 1 year and had the capacity to consent were approached between January and December 2017. Patients underwent a researcher-led telephone interview using a semi-structured questionnaire to assess the impact of emergency laparotomy on overall, general and physical health (Glasgow Benefit Inventory) as well as employment status. The symptoms that patients experienced and their impact were also recorded. RESULTS: Forty-two patients responded to and completed the questionnaire. Just over one-third of patients experienced a deterioration in their general or physical health and 21% of patients experienced a change in employment. Factors which significantly impacted on health status were stoma issues, postoperative morbidity and a change in employment (p < 0.05). The main symptoms which patients identified as being troublesome were altered bowel habit and stoma issues with a resultant social and psychological impact. CONCLUSIONS: One-third of patients experienced a deterioration in their psychosocial and physical health status as well as a change in employment during the first-year postsurgery. Larger research studies are required to define the impact of emergency laparotomy on patients in the longer term and more research is needed to improve perioperative rehabilitation in the postoperative period to ensure optimal functional gain after technically successful surgery.
Subject(s)
Employment , Laparotomy , Humans , Health Status , Patient Discharge , Patient Reported Outcome MeasuresABSTRACT
Many bacterial surface proteins and carbohydrates are modified with phosphorylcholine (ChoP), which contributes to host mimicry and can also promote colonization and survival in the host. However, the ChoP biosynthetic pathways that are used in bacterial species that express ChoP have not been systematically studied. For example, the well-studied Lic-1 pathway is absent in some ChoP-expressing bacteria, such as Neisseria meningitidis and Neisseria gonorrhoeae. This raises a question as to the origin of the ChoP used for macromolecule biosynthesis in these species. In the current study, we used in silico analyses to identify the potential pathways involved in ChoP biosynthesis in genomes of the 26 bacterial species reported to express a ChoP-modified biomolecule. We used the four known ChoP biosynthetic pathways and a ChoP transferase as search terms to probe for their presence in these genomes. We found that the Lic-1 pathway is primarily associated with organisms producing ChoP-modified carbohydrates, such as lipooligosaccharide. Pilin phosphorylcholine transferase A (PptA) homologs were detected in all bacteria that express ChoP-modified proteins. Additionally, ChoP biosynthesis pathways, such as phospholipid N-methyltransferase (PmtA), phosphatidylcholine synthase (Pcs), or the acylation-dependent phosphatidylcholine biosynthesis pathway, which generate phosphatidylcholine, were also identified in species that produce ChoP-modified proteins. Thus, a major finding of this study is the association of a particular ChoP biosynthetic pathway with a cognate, target ChoP-modified surface factor; i.e., protein versus carbohydrate. This survey failed to identify a known biosynthetic pathway for some species that express ChoP, indicating that a novel ChoP biosynthetic pathway(s) may remain to be identified. IMPORTANCE The modification of bacterial surface virulence factors with phosphorylcholine (ChoP) plays an important role in bacterial virulence and pathogenesis. However, the ChoP biosynthetic pathways in bacteria have not been fully understood. In this study, we used in silico analysis to identify potential ChoP biosynthetic pathways in bacteria that express ChoP-modified biomolecules and found the association between a specific ChoP biosynthesis pathway and the cognate target ChoP-modified surface factor.
Subject(s)
Biosynthetic Pathways , Phosphorylcholine , Phosphorylcholine/metabolism , Biosynthetic Pathways/genetics , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Fimbriae Proteins/metabolism , Transferases/metabolismABSTRACT
Neisseria meningitidis historically has been an infrequent and sporadic cause of urethritis and other urogenital infections. However, a nonencapsulated meningococcal clade belonging to the hyperinvasive clonal complex 11.2 lineage has recently emerged and caused clusters of urethritis cases in the United States and other countries. One of the genetic signatures of the emerging N. meningitidis urethritis clade (NmUC) is a chromosomal gene conversion event resulting in the acquisition of the Neisseria gonorrhoeae denitrification apparatus-the N. gonorrhoeae alleles encoding the nitrite reductase AniA, the nitric oxide (NO) reductase NorB, and the intergenic promoter region. The biological importance of the N. gonorrhoeae AniA-NorB for adaptation of the NmUC to a new environmental niche is investigated herein. We found that oxygen consumption, nitrite utilization, and NO production were significantly altered by the conversion event, resulting in different denitrifying aerobic and microaerobic growth of the clade. Further, transcription of aniA and norB in NmUC isolates differed from canonical N. meningitidis, and important polymorphisms within the intergenic region, which influenced aniA promoter activity of the NmUC, were identified. The contributions of three known meningococcal regulators (NsrR, FNR, and NarQP) in controlling the denitrification pathway and endogenous NO metabolism were distinct. Overall, transcription of aniA was dampened relative to canonical N. meningitidis, and this correlated with the lower NO accumulation in the clade. Denitrification and microaerobic respiration were bolstered, and protection against host-derived NO was likely enhanced. The acquisition of the N. gonorrhoeae denitrification pathway by the NmUC supports the clade's adaptation and survival in a microaerobic urogenital environment.
Subject(s)
Gonorrhea , Neisseria meningitidis , Urethritis , United States , Humans , Neisseria meningitidis/genetics , Neisseria meningitidis/metabolism , Neisseria gonorrhoeae/genetics , Neisseria gonorrhoeae/metabolism , Nitric Oxide/metabolism , RespirationABSTRACT
BACKGROUND: Little is known about the opportunities for shared decision-making when older high-risk patients are offered major surgery. This study examines how, when, and why clinicians and patients can share decision-making about major surgery. METHODS: This was a multi-method qualitative study, combining video recordings of preoperative consultations, interviews, and focus groups (33 patients, 19 relatives, 36 clinicians), with observations and documentary analysis in clinics in five hospitals in the UK undertaking major orthopaedic, colorectal, and/or cardiac surgery. RESULTS: Three opportunities for shared decision-making about major surgery were identified. Resolution-focused consultations (cardiac/colorectal) resulted in a single agreed preferred option related to a potentially life-threatening problem, with limited opportunities for shared decision-making. Evaluative and deliberative consultations offered more opportunity. The former focused on assessing the likelihood of benefits of surgery for a presenting problem that was not a threat to life for the patient (e.g., orthopaedic consultations) and the latter (largely colorectal) involved discussion of a range of options while also considering significant comorbidities and patient preferences. The extent to which opportunities for shared decision-making were available, and taken up by surgeons, was influenced by the nature of the presenting problem, clinical pathway, and patient trajectory. CONCLUSIONS: Decisions about major surgery were not always shared between patients and doctors. The nature of the presenting problem, comorbidities, clinical pathways, and patient trajectories all informed the type of consultation and opportunities for sharing decision-making. Our findings have implications for clinicians, with shared decision-making about major surgery most feasible when the focus is on life-enhancing treatment.
Subject(s)
Colorectal Neoplasms , Surgeons , Humans , Decision Making , Decision Making, Shared , Video Recording , Patient Participation , Physician-Patient RelationsABSTRACT
Grief is an expected response to an internalized sense of loss, regardless of age. This response occurs after experiencing the death of a loved one or a drastic life change that creates a sense of loss. Children and adolescents move through the grief process according to their age and stage of development. Proper support is essential to promote healthy coping and acceptance in youth experiencing grief. The interprofessional school team can support students experiencing grief to enhance student learning outcomes and overall health and well-being.
Subject(s)
Adaptation, Psychological , Bereavement , Grief , Humans , Male , Female , Child , Adolescent , Health Promotion , Psychosocial Support SystemsABSTRACT
Phosphorylcholine (ChoP) can be found in all life forms. Although this molecule was first thought to be uncommon in bacteria, it is now appreciated that many bacteria express ChoP on their surface. ChoP is usually attached to a glycan structure, but in some cases, it is added as a post-translational modification to proteins. Recent findings have demonstrated the role of ChoP modification and phase variation (ON/OFF switching) in bacterial pathogenesis. However, the mechanisms of ChoP synthesis are still unclear in some bacteria. Here, we review the literature and examine the recent developments in ChoP-modified proteins and glycolipids and of ChoP biosynthetic pathways. We discuss how the well-studied Lic1 pathway exclusively mediates ChoP attachment to glycans but not to proteins. Finally, we provide a review of the role of ChoP in bacterial pathobiology and the role of ChoP in modulating the immune response.
Subject(s)
Bacteria , Phosphorylcholine , Phosphorylcholine/metabolism , Bacteria/metabolism , PolysaccharidesABSTRACT
Neisseria gonorrhoeae has developed resistance to all previous antibiotics used for treatment. This highlights a crucial need for novel antimicrobials to treat gonococcal infections. We previously showed that carbamazepine (Cz), one of the most commonly prescribed antiepileptic drugs, can block the interaction between gonococcal pili and the I-domain region of human complement receptor 3 (CR3)-an interaction that is vital for infection of the female cervix. We also show that Cz can completely clear an established N. gonorrhoeae infection of primary human cervical cells. In this study, we quantified Cz in serum, saliva, and vaginal fluid collected from 16 women who were, or were not, regularly taking Cz. We detected Cz in lower reproductive tract mucosal secretions in the test group (women taking Cz) at potentially therapeutic levels using a competitive ELISA. Furthermore, we found that Cz concentrations present in vaginal fluid from women taking this drug were sufficient to result in a greater than 99% reduction (within 24 h) in the number of viable gonococci recovered from ex vivo, human, primary cervical cell infections. These data provide strong support for the further development of Cz as a novel, host-targeted therapy to treat gonococcal cervicitis.
Subject(s)
Epilepsy , Gonorrhea , Humans , Female , Drug Repositioning , Gonorrhea/drug therapy , Neisseria gonorrhoeae , Carbamazepine/therapeutic use , Carbamazepine/pharmacologyABSTRACT
Decellularised porcine superflexor tendon (pSFT) has been characterised as a suitable scaffold for anterior cruciate ligament replacement, with dimensions similar to hamstring tendon autograft. However, decellularisation of tissues may reduce or damage extracellular matrix components, leading to undesirable biomechanical changes at a whole tissue scale. Although the role of collagen in tendons is well established, the mechanical contribution of glycosaminoglycans (GAGs) is less evident and could be altered by the decellularisation process. In this study, the contribution of GAGs to the tensile and compressive mechanical properties of pSFT was determined and whether decellularisation affected these properties by reducing GAG content or functionality. PSFTs were either enzymatically treated using chondroitinase ABC to remove GAGs or decellularised using previously established methods. Native, GAG-depleted and decellularised pSFT groups were then subjected to quantitative assays and biomechanical characterisation. In tension, specimens underwent stress relaxation and strength testing. In compression, specimens underwent confined compression testing. The GAG-depleted group was found to have circa 86% reduction of GAG content compared to native and decellularised groups. There was no significant difference in GAG content between native (3.75 ± 0.58 µg/mg) and decellularised (3.40 ± 0.37 µg/mg) groups. Stress relaxation testing discovered the time-independent and time-dependent relaxation moduli of the decellularised group were reduced ≥50% compared to native and GAG-depleted groups. However, viscoelastic behaviour of native and GAG-depleted groups resulted similar. Strength testing discovered no differences between native and GAG-depleted group's properties, albeit a reduction â¼20% for decellularised specimens' linear modulus and tensile strength compared to native tissue. In compression testing, the aggregate modulus was found to be circa 74% lower in the GAG-depleted group than the native and decellularised groups, while the zero-strain permeability was significantly higher in the GAG-depleted group (0.86 ± 0.65 mm4/N) than the decellularised group (0.03 ± 0.04 mm4/N). The results indicate that GAGs may significantly contribute to the mechanical properties of pSFT in compression, but not in tension. Furthermore, the content and function of GAGs in pSFTs are unaffected by decellularisation and the mechanical properties of the tissue remain comparable to native tissue.
Subject(s)
Glycosaminoglycans , Tendons , Animals , Swine , Anterior Cruciate Ligament , Collagen , Physical Phenomena , Biomechanical PhenomenaABSTRACT
The US Neisseria meningitidis urethritis clade (US_NmUC) harbors gonococcal deoxyribonucleic acid alleles and causes gonorrhea-like urogenital tract disease. A large convenience sample of US_NmUC isolates (N = 122) collected between January 2015 and December 2019 in Columbus, Ohio demonstrated uniform susceptibility to antibiotics recommended for gonorrhea treatment and meningococcal chemoprophylaxis.
ABSTRACT
Gonorrhea remains a major global public health problem because of the high incidence of infection (estimated 82 million cases in 2020) and the emergence and spread of Neisseria gonorrhoeae strains resistant to previous and current antibiotics used to treat infections. Given the dearth of new antibiotics that are likely to enter clinical practice in the near future, there is concern that cases of untreatable gonorrhea might emerge. In response to this crisis, the World Health Organization (WHO), in partnership with the Global Antibiotic Research and Development Partnership (GARDP), has made the search for and development of new antibiotics against N. gonorrhoeae a priority. Ideally, these antibiotics should also be active against other sexually transmitted organisms, such as Chlamydia trachomatis and/or Mycoplasma genitalium, which are often found with N. gonorrhoeae as co-infections. Corallopyronin A is a potent antimicrobial that exhibits activity against Chlamydia spp. and inhibits transcription by binding to the RpoB switch region. Accordingly, we tested the effectiveness of corallopyronin A against N. gonorrhoeae. We also examined the mutation frequency and modes of potential resistance against corallopyronin A. We report that corallopyronin A has potent antimicrobial action against antibiotic-susceptible and antibiotic-resistant N. gonorrhoeae strains and could eradicate gonococcal infection of cultured, primary human cervical epithelial cells. Critically, we found that spontaneous corallopyronin A-resistant mutants of N. gonorrhoeae are exceedingly rare (≤10-10) when selected at 4× the MIC. Our results support pre-clinical studies aimed at developing corallopyronin A for gonorrheal treatment regimens. IMPORTANCE The high global incidence of gonorrhea, the lack of a protective vaccine, and the emergence of N. gonorrhoeae strains expressing resistance to currently used antibiotics demand that new treatment options be developed. Accordingly, we investigated whether corallopyronin A, an antibiotic which is effective against other pathogens, including C. trachomatis, which together with gonococci frequently cause co-infections in humans, could exert anti-gonococcal action in vitro and ex vivo, and potential resistance emergence. We propose that corallopyronin A be considered a potential future treatment option for gonorrhea because of its potent activity, low resistance development, and recent advances in scalable production.
Subject(s)
Anti-Infective Agents , Coinfection , Gonorrhea , Humans , Gonorrhea/drug therapy , Gonorrhea/prevention & control , Neisseria gonorrhoeae/genetics , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Chlamydia trachomatis , Anti-Infective Agents/pharmacologyABSTRACT
Multidrug-resistant (MDR) N. gonorrhoeae is a current public health threat. New therapies are urgently needed. PBT2 is an ionophore that disrupts metal homeostasis. PBT2 administered with zinc is shown to reverse resistance to antibiotics in several bacterial pathogens. Here we show that both N. meningitidis and MDR N. gonorrhoeae are sensitive to killing by PBT2 alone. PBT2 is, thus, a candidate therapeutic for MDR N. gonorrhoeae infections.
Subject(s)
Gonorrhea , Neisseria meningitidis , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Gonorrhea/drug therapy , Gonorrhea/microbiology , Humans , Ionophores/pharmacology , Ionophores/therapeutic use , Microbial Sensitivity Tests , Neisseria gonorrhoeae , ZincABSTRACT
The ammoximation of cyclohexanone using preformed hydrogen peroxide (H2O2) is currently applied commercially to produce cyclohexanone oxime, an important feedstock in nylon-6 production. We demonstrate that by using supported gold-palladium (AuPd) alloyed nanoparticles in conjunction with a titanium silicate-1 (TS-1) catalyst, H2O2 can be generated in situ as needed, producing cyclohexanone oxime with >95% selectivity, comparable to the current industrial route. The ammoximation of several additional simple ketones is also demonstrated. Our approach eliminates the need to transport and store highly concentrated, stabilized H2O2, potentially achieving substantial environmental and economic savings. This approach could form the basis of an alternative route to numerous chemical transformations that are currently dependent on a combination of preformed H2O2 and TS-1, while allowing for considerable process intensification.
ABSTRACT
Sol immobilization is used to produce bimetallic catalysts with higher activity to monometallic counterparts for a wide range of environmental and commercial catalytic transformations. Analysis of complementary surface characterization (XPS, Boehm's titration, and zeta potential measurements) was used to elucidate alterations in the surface functionality of two activated carbon supports during acid exposure. When considered in parallel to the experimentally determined electrostatic and conformational changes of the polymer surrounding the nanoparticles, an electrostatic model is proposed describing polymer protected nanoparticle deposition with several polymer-carbon support examples described. Consideration of the electrostatic interactions ensures full deposition of the polymer protected nanoparticles and at the same time influences the structure of the bimetallic nanoparticle immobilized on the support. The normalized activity of AuPd catalysts prepared with 133 ppm H2SO4 has a much higher activity for the direct synthesis of hydrogen peroxide compared to catalysts prepared in the absence of acid. Detailed characterization by XPS indicates that the surface becomes enriched in Au in the Au-Pd samples prepared with acid, suggesting an improved dispersion of smaller bimetallic nanoparticles, rich in Au, that are known to be highly active for the direct synthesis reaction. Subsequent microscopy measurements confirmed this hypothesis, with the acid addition catalysts having a mean particle size â¼2 nm smaller than the zero acid counterparts. The addition of acid did not result in a morphology change, and random alloyed bimetallic AuPd nanoparticles were observed in catalysts prepared by sol immobilization in the presence and absence of acid. This work shows that the deposition of polymer protected AuPd nanoparticles onto activated carbon is heavily influenced by the acid addition step in the sol immobilization process. The physicochemical properties of both the polymer and the activated carbon support should be considered when designing a bimetallic nanoparticle catalyst by sol immobilization to ensure the optimum performance of the final catalyst.
ABSTRACT
Transmission of HIV across the mucosal surface of the female reproductive tract to engage subepithelial CD4-positive T cells is not fully understood. Cervical epithelial cells express complement receptor 3 (CR3) (integrin αMß2 or CD11b/CD18). In women, the bacterium Neisseria gonorrhoeae uses CR3 to invade the cervical epithelia to cause cervicitis. We hypothesized that HIV may also use CR3 to transcytose across the cervical epithelia. Here, we show that HIV-1 strains bound with high affinity to recombinant CR3 in biophysical assays. HIV-1 bound CR3 via the I-domain region of the CR3 alpha subunit, CD11b, and binding was dependent on HIV-1 N-linked glycans. Mannosylated glycans on the HIV surface were a high-affinity ligand for the I-domain. Man5 pentasaccharide, representative of HIV N-glycans, could compete with HIV-1 for CR3 binding. Using cellular assays, we show that HIV bound to CHO cells by a CR3-dependent mechanism. Antibodies to the CR3 I-domain or to the HIV-1 envelope glycoprotein blocked the binding of HIV-1 to primary human cervical epithelial (Pex) cells, indicating that CR3 was necessary and sufficient for HIV-1 adherence to Pex cells. Using Pex cells in a Transwell model system, we show that, following transcytosis across an intact Pex cell monolayer, HIV-1 is able to infect TZM-bl reporter cells. Targeting the HIV-CR3 interaction using antibodies, mannose-binding lectins, or CR3-binding small-molecule drugs blocked HIV transcytosis. These studies indicate that CR3/Pex may constitute an efficient pathway for HIV-1 transmission in women and also demonstrate strategies that may prevent transmission via this pathway. IMPORTANCE In women, the lower female reproductive tract is the primary site for HIV infection. How HIV traverses the epithelium to infect CD4 T cells in the submucosa is ill-defined. Cervical epithelial cells have a protein called CR3 on their surface. We show that HIV-1 binds to CR3 with high affinity and that this interaction is necessary and sufficient for HIV adherence to, and transcytosis across, polarized, human primary cervical epithelial cells. This suggests a unique role for CR3 on epithelial cells in dually facilitating HIV-1 attachment and entry. The HIV-CR3 interaction may constitute an efficient pathway for HIV delivery to subepithelial lymphocytes following virus transmission across an intact cervical epithelial barrier. Strategies with potential to prevent transmission via this pathway are presented.
Subject(s)
HIV Infections , HIV Seropositivity , HIV-1 , Cricetinae , Animals , Humans , Female , Macrophage-1 Antigen/metabolism , HIV-1/metabolism , Cricetulus , Epithelial Cells/microbiology , CHO Cells , Transcytosis , Polysaccharides/metabolismABSTRACT
Tissue engineered bone solutions aim to overcome the limitations of autologous and allogeneic grafts. Decellularised tissues are produced by washing cellular components from human or animal tissue to produce an immunologically safe and biocompatible scaffold, capable of integration following implantation. A decellularisation procedure utilising low concentration sodium dodecyl sulphate (0.1% w/v) was applied to trabecular bone from human femoral heads (FH) and tibial plateaus (TP). Biological (histology, DNA quantification), biomechanical (compression testing) and structural (µCT) comparisons were made between decellularised and unprocessed cellular tissue. Total DNA levels of decellularised FH and TP bone were below 50 ng mg-1 dry tissue weight and nuclear material was removed. No differences were found between cellular and decellularised bone, from each anatomical region, for all the biomechanical and structural parameters investigated. Differences were found between cellular FH and TP and between decellularised FH and TP. Decellularised FH had a higher ultimate compressive stress, Young's modulus and 0.2% proof stress than decellularised TP (p = 0.001, 0.002, 0.001, Mann Whitney U test, MWU). The mineral density of cellular and decellularised TP bone was significantly greater than cellular and decellularised FH bone respectively (cellular: p = 0.001, decellularised: p < 0.001, MWU). The bone volume fraction and trabecular thickness of cellular and decellularised FH bone were significantly greater than cellular and decellularised TP bone respectively (cellular: p = 0.001, 0.005; decellularised: p < 0.001, <0.001, MWU). Characterisation of decellularised trabecular bone from different anatomical regions offers the possibility of product stratification, allowing selection of biomechanical properties to match particular anatomical regions undergoing bone graft procedures.