Activation of cytokines and NF-kappa B in corneal epithelial cells infected by respiratory syncytial virus: potential relevance in ocular inflammation and respiratory infection

BACKGROUND: Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection, claiming millions of lives annually. The virus infects various cells of the respiratory tract as well as resident inflammatory cells such as macrophages. Infection activates a variety of cellular factors such as cytokines and the pro-inflammatory transcription factor, NF-kappa B, all of which are important players in the respiratory disease. However, the exact natural route of RSV infection and its etiology remain relatively unknown. In this paper, we test the hypothesis that human corneal epithelial cells, which constitute the outermost layer of the cornea, can be infected with RSV, and that the infection leads to the activation of proinflammatory macromolecules. RESULTS: Corneal swabs obtained from pediatric patients with acute respiratory disease were found to contain RSV at a high frequency (43 positive out of 72 samples, i.e., 60%). Primary corneal epithelial cells in tissue culture supported robust infection and productive growth of RSV. Infection resulted in the activation of TNF-α, IL-6 and sixteen chemokines as well as NF-κB. Three proinflammatory CXC chemokines (MIG, I-TAC, IP-10) underwent the greatest activation. CONCLUSIONS: The ocular epithelium is readily infected by RSV. The pro-inflammatory cytokines are likely to play critical roles in the etiology of inflammation and conjunctivitis commonly seen in pediatric patients with respiratory infections. RSV-eye interactions have important implications in RSV transmission, immunopathology of RSV disease, and in the management of conjunctivitis

Differential regulation of ENA-78 and GCP-2 gene expression in human corneal keratocytes and epithelial

PURPOSE. To determine whether interleukin (IL)-1␣-and tumor necrosis factor (TNF)-␣-stimulated human corneal epithelial cells (HCECs) and human corneal keratocytes (HCKs) produce the ␣-chemokines epithelial cell-derived neutrophil attractant (ENA)-78 and granulocyte chemotactic protein (GCP)-2. METHODS. Cultures of HCECs and HCKs were stimulated with either human recombinant IL-1␣ or TNF-␣. At selected times after stimulation, culture supernatants were harvested and assayed for ENA-78 and GCP-2 by enzyme-linked immunosorbent assay. RNA was extracted from cell cultures to measure steady state levels of intracellular ENA-78 and GCP-2 pre-mRNA and mRNA by the reverse transcription-polymerase chain reaction. RESULTS. Exposure of HCECs to either IL-1␣ or TNF-␣ stimulated a more than 4.5-fold increase in ENA-78 RNA and protein synthesis without stimulating a significant increase in either GCP-2 RNA synthesis or protein production. Exposure of HCK to IL-1␣ stimulated a 10-fold increase in ENA-78 and GCP-2 RNA synthesis and a more than 300-fold increase in ENA-78 and GCP-2 protein production. In contrast, exposure of keratocytes to TNF-␣ significantly enhanced ENA-78 RNA synthesis, resulting in a more than 68-fold increase in ENA-78 protein synthesis without significantly enhancing either GCP-2 gene expression or protein secretion. CONCLUSIONS. ENA-78 gene expression is significantly enhanced in both HCECs and HCKs in response to either IL-1␣ or TNF-␣ stimulation. In contrast, GCP-2 synthesis is only inducible in IL-1␣-stimulated HCKs. The results suggest that GCP-2 gene expression is more tightly regulated in diseased or injured corneal tissue than is ENA-78 gene expression. (Invest Ophthalmol Vis Sci. 2003;44:3432-3437

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Passive transfer of anti-herpes simplex virus type 2 monoclonal and polyclonal antibodies protect against herpes simplex virus type 1-induced but not herpes simplex virus type 2-induced stromal keratitis

Purpose. To investigate whether passive transfer of antibodies to viral glycoproteins would protect against herpes simplex virus type 2-induced stromal keratitis. Methods. Balb/c mice were infected on the scarified cornea with herpes simplex virus types 1 or 2 (HSV-1 and HSV-2, respectively), and monoclonal or polyclonal antibodies were administered intraperitoneally 24 hr later. Eyes were monitored for corneal opacity. Flow cytometry was used to examine the expression of glycoproteins on the surface of HSV-infected cells. Results. Passive transfer of monoclonal antibodies to viral glycoproteins gB, gD, or gE or anti-HSV-2 hyperimmune serum were all highly effective (P < 0.005) at preventing blinding disease induced by HSV-1. In contrast, none of the antibody preparations could prevent stromal keratitis when the animals were challenged with various HSV-2 strains. However, antibody treatment could prevent the development of fatal encephalitis in the majority of HSV-2 infected hosts. Flow cytometry analysis revealed that gD and gB expression on the membranes of HSV-2 infected corneal epithelial cells isolated from excised corneas was substantially less (P < 0.005) than that detected on HSV-1 infected cells at both 24 and 48 hours postinfection. This antigenic difference was not due to the failure of HSV-2 to replicate in corneal epithelial cells in vivo. Conclusions. Decreased levels of membrane glycoprotein antigen expression may be one factor contributing to the refractiveness of HSV-2-induced ocular disease to humoral immunotherapy. Invest Ophthalmol Vis Sci. 1993; 34:2460-2468 Jrierpes simplex keratitis is the most common cause of corneal disease and the second leading cause of blindness in the United States. 12 Although herpes simplex virus type 1 (HSV-1) has traditionally been associated with herpetic eye disease, herpes simplex virus type 2 (HSV-2) eye infections are becoming increas

Human Corneal Epithelial Cells Synthesize ELR−α-Chemokines in Response to Proinflammatory Mediators

The purpose of this study was to characterize the synthesis of alpha-chemokines IP-10, MIG, and I-TAC by human corneal epithelial cells (HCE) following exposure to proinflammatory mediators. Supernatants were collected from HCE cultures stimulated with individual or combinations of TNF-alpha, IL-1alpha, and IFN-gamma, and assayed for alpha-chemokines by ELISA. RT-PCR was used to detect IFN-gamma receptor mRNA. Activation of STAT 1 was determined by Western blotting. Stimulation of HCE with either IL-1alpha or TNF-alpha increased IP-10 protein synthesis up to 6-fold, whereas insignificant levels of MIG and I-TAC were induced. The epithelial cells were found to express IFN-gamma receptors constitutively. Exposure to the ligand resulted in STAT 1 phosphorylation and production of nanogram amounts of IP-10, I-TAC, and MIG. When HCE were stimulated with combinations of TNF-alpha and IFN-gamma, or IL-1alpha and IFN-gamma, the levels of IP-10 and I-TAC secreted were \u3e 150-fold higher than that produced following exposure to a single cytokine. In contrast, MIG protein synthesis was not enhanced upon stimulation with cytokine combinations. The abundant production of ELR(-)alpha -chemokines following appropriate stimulation suggests that HCE may play an important role in the recruitment of effector cells such as activated T-lymphocytes to inflamed corneal tissue. The data also indicate that the synthesis of IP-10, I-TAC, and MIG are differentially regulated in HCE

Synthesis of Alpha-Chemokines IP-10, I-TAC, and MIG are Differentially Regulated in Human Corneal Keratocytes

PURPOSE: Chemokines responsible for recruiting lymphocytes such as activated T cells into the cornea have not been clearly defined. IP-10, I-TAC, and MIG are chemoattractants for these lymphocytes. The goal of this study was to determine whether human corneal keratocyte (HCKs) in culture synthesize these chemokines in response to proinflammatory mediators. METHODS: HCKs grown in vitro were stimulated with IL-1alpha, TNF-alpha, or IFN-gamma. Induction of alpha-chemokine gene expression was quantitated by real-time PCR and ELISA. Activation of the transcriptional activator STAT1 by IFN-gamma receptors expressed on HCKs was determined by Western blot analysis. RESULTS: HCKs incubated with TNF-alpha, IL-1alpha, or IFN-gamma resulted in a \u3e2000-fold increase in IP-10 protein secretion by 36 hours after stimulation. In contrast, stimulation with TNF-alpha, IL-1alpha, or IFN-gamma induced levels of MIG and I-TAC that were not significantly greater than constitutive levels. Treatment of HCKs with IFN-gamma activated STAT1 and, in combination with either TNF-alpha or IL-1alpha, enhanced MIG and I-TAC synthesis \u3e20-fold. CONCLUSIONS: IP-10 synthesis is induced in HCKs by IL-1alpha, TNF-alpha, and IFN-gamma. In contrast, induction of I-TAC and MIG synthesis in HCKs requires costimulation with IFN-gamma and either IL-1alpha or TNF-alpha. The results suggest therefore, that the upregulation of I-TAC and MIG gene expression at sites of corneal inflammation are more tightly regulated than that of IP-10. A role for differential induction of the three alpha-chemokine genes in corneal inflammatory processes at the eye surface is discussed

IL-17 Receptor Signaling Influences Virus-Induced Corneal Inflammation

IL-17 has been associated with selected inflammatory and autoimmune diseases. We characterized the expression of this proinflammatory cytokine following HSV-1 corneal infection and investigated whether IL-17R signaling modulated the host response to the viral pathogen at early time-points postinfection. IL-17 was elevated in the murine cornea 24 h after high-dose virus infection and subsequently persisted at low levels during the first week. Immunofluorescent studies showed that the IL-17R was expressed by cultured mouse corneal fibroblasts. Exposure of corneal cells to IL-17 led to production of IL-6 and MIP-2 in vitro and in vivo, indicating that the IL-17R was functional. Mice lacking IL-17R displayed significantly reduced neutrophil infiltration and corneal opacity. However, this effect was transient, as corneal pathology and neutrophil influx resembled that of wild-type (WT) hosts 4 days postinfection. HSV-1 growth and clearance in IL-17R(-/-) hosts were similar to that of the WT controls. Infection of IFN-gamma gene knockout mice was associated with elevated IL-17 levels and accelerated corneal opacity, suggesting that IFN-gamma negatively regulated IL-17 expression. Collectively, our results establish that IL-17 is rapidly produced in the cornea after HSV-1 infection and is regulated at least in part by IFN-gamma. The absence of IL-17 signaling results in a transient decrease in the expression of proinflammatory mediators, neutrophil migration, and corneal pathology, but control of virus growth in the cornea and trigeminal ganglia is not compromised. Thus, IL-17 actively influences early virus-induced corneal inflammation

Differential regulation of ENA-78 and GCP-2 gene expression in human corneal keratocytes and epithelial cells

PURPOSE: To determine whether interleukin (IL)-1alpha- and tumor necrosis factor (TNF)-alpha-stimulated human corneal epithelial cells (HCECs) and human corneal keratocytes (HCKs) produce the alpha-chemokines epithelial cell-derived neutrophil attractant (ENA)-78 and granulocyte chemotactic protein (GCP)-2. METHODS: Cultures of HCECs and HCKs were stimulated with either human recombinant IL-1alpha or TNF-alpha. At selected times after stimulation, culture supernatants were harvested and assayed for ENA-78 and GCP-2 by enzyme-linked immunosorbent assay. RNA was extracted from cell cultures to measure steady state levels of intracellular ENA-78 and GCP-2 pre-mRNA and mRNA by the reverse transcription-polymerase chain reaction. RESULTS: Exposure of HCECs to either IL-1alpha or TNF-alpha stimulated a more than 4.5-fold increase in ENA-78 RNA and protein synthesis without stimulating a significant increase in either GCP-2 RNA synthesis or protein production. Exposure of HCK to IL-1alpha stimulated a 10-fold increase in ENA-78 and GCP-2 RNA synthesis and a more than 300-fold increase in ENA-78 and GCP-2 protein production. In contrast, exposure of keratocytes to TNF-alpha significantly enhanced ENA-78 RNA synthesis, resulting in a more than 68-fold increase in ENA-78 protein synthesis without significantly enhancing either GCP-2 gene expression or protein secretion. CONCLUSIONS: ENA-78 gene expression is significantly enhanced in both HCECs and HCKs in response to either IL-1alpha or TNF-alpha stimulation. In contrast, GCP-2 synthesis is only inducible in IL-1alpha-stimulated HCKs. The results suggest that GCP-2 gene expression is more tightly regulated in diseased or injured corneal tissue than is ENA-78 gene expression