Holly Carveth

Neutrophil activating factor (NAF) induces polymorphonuclear leukocyte adherence to endothelial cells and to subendothelial matrix proteins

Neutrophil activating factor is a polypeptide cytokine released from stimulated mononuclear phagocytes and endothelial cells. We found that neutrophil activating factor induced time- and concentration-dependent binding of human polymorphonuclear leukocytes to endothelial monolayers and subendothelial matrix proteins, via a mechanism that involves altered expression of the leukocyte CD11/CD18 glycoproteins. Thus, neutrophil activating factor is a third mediator, in addition to platelet-activating factor and endothelial leukocyte adhesion molecule 1, that is synthesized by activated endothelium and that can induce polymorphonuclear leukocyte adhesion to endothelial cells. Because NAF is released into the pericellular fluid, it may also stimulate binding of the leukocytes to exposed subendothelial structures at sites of vascular injury.

Human endothelial cells regulate polymorphonuclear leukocyte degranulation

Neutrophil degranulation is an important event in inflammatory responses. We examined the regulation of neutrophil (PMN) degranulation by resting and activated human endothelial cells. Whereas PMNs adherent to endothelial cells that were stimulated to express P‐selectin and platelet‐activating factor did not release the specific granule marker lactoferrin or the primary granule enzyme, elastase, PMNs adherent to endothelial cells stimulated with interleukin‐1 (IL‐1) or tumor necrosis factor secreted both. PMN degranulation was dependent on the time of incubation of endothelial cells with the cytokine, its concentration, and the time of incubation of the PMNs with endothelial cells. Degranulation of PMNs and their adhesion to stimulated endothelial cells are correlated events, but they could be dissociated by blocking the tethering molecules used by the endothelial cells and neutrophils under these conditions. This suggested that paracrine signaling molecules that induce PMN degranulation are produced by cytokine‐stimulated endothelial cells. We found that endothelial cells stimulated with IL‐1 release newly synthesized degranulating factors that require transcription and translation. IL‐8 was synthesized, released, and signaled granular secretion by PMNs. However, experiments with blocking antibodies indicated the presence of an additional degranulating factor not accounted for by IL‐8. These experiments demonstrate that human endothelial cells regulate degranulation of neutrophils by generating signaling factors that are expressed differentially depending on the endothelial agonist and other features. Active modification of neutrophil granular secretion by endothelial cells can influence physiologic acute inflammatory responses but may also contribute to pathologic vascular and tissue damage.—Topham, M. K., Carveth, H. J., Mcintyre, T. M., Prescott, S. M., Zimmerman, G. A. Human endothelial cells regulate polymorphonuclear leukocyte degranulation. FASEB J. 12, 733–746 (1998)

Sputum biomarkers and the prediction of clinical outcomes in patients with cystic fibrosis

Lung function, acute pulmonary exacerbations (APE), and weight are the best clinical predictors of survival in cystic fibrosis (CF); however, underlying mechanisms are incompletely understood. Biomarkers of current disease state predictive of future outcomes might identify mechanisms and provide treatment targets, trial endpoints and objective clinical monitoring tools. Such CF-specific biomarkers have previously been elusive. Using observational and validation cohorts comprising 97 non-transplanted consecutively-recruited adult CF patients at the Intermountain Adult CF Center, University of Utah, we identified biomarkers informative of current disease and predictive of future clinical outcomes. Patients represented the majority of sputum producers. They were recruited March 2004-April 2007 and followed through May 2011. Sputum biomarker concentrations were measured and clinical outcomes meticulously recorded for a median 5.9 (interquartile range 5.0 to 6.6) years to study associations between biomarkers and future APE and time-to-lung transplantation or death. After multivariate modeling, only high mobility group box-1 protein (HMGB-1, mean = 5.84 [log ng/ml], standard deviation [SD] = 1.75) predicted time-to-first APE (hazard ratio [HR] per log-unit HMGB-1 = 1.56, p-value = 0.005), number of future APE within 5 years (0.338 APE per log-unit HMGB-1, p<0.001 by quasi-Poisson regression) and time-to-lung transplantation or death (HR = 1.59, p = 0.02). At APE onset, sputum granulocyte macrophage colony stimulating factor (GM-CSF, mean 4.8 [log pg/ml], SD = 1.26) was significantly associated with APE-associated declines in lung function (−10.8 FEV1% points per log-unit GM-CSF, p<0.001 by linear regression). Evaluation of validation cohorts produced similar results that passed tests of mutual consistency. In CF sputum, high HMGB-1 predicts incidence and recurrence of APE and survival, plausibly because it mediates long-term airway inflammation. High APE-associated GM-CSF identifies patients with large acute declines in FEV1%, possibly providing a laboratory-based objective decision-support tool for determination of an APE diagnosis. These biomarkers are potential CF reporting tools and treatment targets for slowing long-term progression and reducing short-term severity.

Bacterial lipopolysaccharide induces endothelial cells to synthesize a degranulating factor for neutrophils

Enzymes and other factors secreted by degranulating neutrophils (polymorphonuclear leukocytes, PMNs) mediate endothelial injury, thrombosis, and vascular remodeling. In bacteremia and sepsis syndrome and their consequent complications (including acute respiratory distress syndrome and systemic ischemia‐reperfusion resulting from septic shock), neutrophil degranulation is an important mechanism of injury. In related studies, we found that human endothelial cells regulate neutrophil degranulation and that inflammatory cytokines induce synthesis of degranulating factors by human endothelial cells. Here we show that lipopolysaccharides (LPS) from gram‐negative bacteria were the most potent agonists for release of degranulating activity by endothelial cells when compared to several cytokines and stimulatory factors. LPS also induced the release of degranulating signals for PMNs from a human endothelial cell line, EA.hy 926. Interleukin 8 (IL‐8) is synthesized by endothelial and EA.hy 926 cells in response to LPS and induces neutrophil degranulation. However, complementary strategies using receptor desensitization, translation of messenger RNA by Xenopus laevis oocytes, and purification and analysis of factors from conditioned supernatants demonstrated that degranulating factors distinct from IL‐8 are generated in response to LPS. The characteristics of a partially purified degranulating factor isolated from conditioned supernatants distinguished it from known chemokines and other factors that induce PMN degranulation and are generated by endothelial cells in response to LPS. Thus, cultured human endothelial cells and endothelial cell lines synthesize several unique signaling molecules that can trigger neutrophil granular secretion. If produced in vivo in response to LPS or other pathologic agonists, these degranulating signals may activate PMNs in combination or in sequence, initiating or propagating vascular damage.—Gill, E. A., Imaizumi, T.‐a., Carveth, H., Topham, M. K., Tarbet, E. B., Mcintyre, T. M., Prescott, S. M., Zimmerman, G. A. Bacterial lipopolysaccharide induces endothelial cells to synthesize a degranulating factor for neutrophils. FASEB J. 12, 673–684 (1998)

Treatment of Condyloma Acuminatum with Three Different Interferons Administered Intralesionallv: A Double-Blind, Placebo Controlled Trial

STUDY OBJECTIVE To determine the efficacy and toxicity of intralesionally administered interferons in the treatment of condyloma acuminatum. DESIGN Randomized, double-blind, and placebo-controlled study. SETTING Outpatient clinics at university medical centers. PATIENTS Seventy-nine patients with biopsy-proved condyloma acuminatum that was refractory to conventional therapy were enrolled in the study. INTERVENTIONS Alpha-2b, alpha-nl-, and beta-interferons were used. One wart on each patients was injected three times per week for 4 weeks with either 1 x 10(6) units of interferon or placebo. MEASUREMENTS AND MAIN RESULTS Forty-seven percent of warts injected with interferon resolved completely, compared with 22% of placebo-injected warts (P = 0.009). In addition, more recipients of interferon had a complete resolution of uninjected lesions. No differences in rates of response were noted among the different interferon groups. Approximately one third of interferon-injected warts recurred, compared with none of four placebo-injected warts. Intralesionally administered interferon was nontoxic and well tolerated, although transient pain on injection was observed frequently. CONCLUSIONS Intralesional administration of each of these three interferons appears to be useful in treating condyloma acuminatum. However, the frequent recurrence of disease and the failure of many lesions to resolve indicate that different regimens, such as longer courses of therapy or different routes of administration, should be evaluated to maximize beneficial effects of interferon for treating this common sexually transmitted disease.