Toll-like receptor-induced expression of epithelial cytokine receptors on haemopoietic progenitors is altered in allergic asthma.

BACKGROUND: Haemopoietic progenitor cells (HPC) migrate to sites of allergic inflammation where, upon stimulation with epithelial cytokines, they produce Th2 cytokines and differentiate into mature eosinophils and basophils. They also express Toll-like receptors (TLR) involved in antimicrobial responses. OBJECTIVE: The objective of this study was to compare TLR expression on peripheral blood HPC and TLR-induced responses, in particular changes in epithelial cytokine receptors, in healthy and asthmatic subjects at baseline and following allergen challenge. METHODS: Ten healthy and 11 allergic asthmatic subjects were studied. HPC-enriched cell populations were stimulated with TLR-2, TLR-4 or TLR-9 ligands. TLR expression by circulating HPC and interleukin (IL)-25 (IL-17RB), IL-33 (ST2) and thymic stromal lymphopoietin receptor (TSLPR) expression after TLR ligation were examined by flow cytometry at baseline and, in asthmatics, following allergen challenge. The effects of dexamethasone (Dex) on TLR-induced responses were also assessed. RESULTS: Asthmatics had significantly lower circulating HPC expressing TLR-2 and TLR-9 with a similar trend for TLR-4. TLR-4 stimulation of HPC yielded higher numbers of TSLPR+ cells in asthmatics compared with healthy subjects. A similar trend was seen for TLR-9 ligation, an effect further augmented by allergen inhalation. Allergen challenge also enhanced TLR-induced ST2 expression on HPC. Treatment with Dex in vitro increased TLR-4-induced TSLPR expression but had no effect on other epithelial cytokine receptors. CONCLUSIONS AND CLINICAL RELEVANCE: These data demonstrate an interaction between allergen and TLR ligand exposure in asthmatics. Allergen inhalation augments the TLR-induced inflammatory response by HPC, possibly leading to increased "in situ haemopoiesis" through up-regulation of TSLPR. These findings show that HPC may be a part of the pro-inflammatory cascade in pathogen-induced asthma exacerbation through their increased responsiveness to TLR stimulation.

Glucagon-like peptide-1 receptor expression on human eosinophils and its regulation of eosinophil activation.

BACKGROUND: Glucagon-like peptide-1 (GLP-1) and its receptor are part of the incretin family of hormones that regulate glucose metabolism. GLP-1 also has immune modulatory roles. OBJECTIVES: To measure the expression of the GLP-1 receptor (GLP-1R) on eosinophils and neutrophils in normal and asthmatic subjects and evaluate effects of a GLP-1 analog on eosinophil function. METHODS: Peripheral blood samples were taken from 10 normal and 10 allergic asthmatic subjects. GLP-1R expression was measured on eosinophils and neutrophils. Subsequently, the asthmatic subjects underwent allergen and diluent inhalation challenges, and GLP-1R expression was measured. Purified eosinophils, collected from mild asthmatic subjects, were stimulated with lipopolysaccharide (LPS) and a GLP-1 analog to evaluate eosinophil cell activation markers CD11b and CD69 and cytokine (IL-4, IL-5, IL-8 and IL-13) production. RESULTS: Glucagon-like peptide-1 receptor is expressed on human eosinophils and neutrophils. Eosinophil, but not neutrophil, expression of GLP-1R is significantly higher in normal controls compared to allergic asthmatics. The expression of GLP-1R did not change on either eosinophils or neutrophils following allergen challenge. A GLP-1 analog significantly decreased the expression of eosinophil-surface activation markers following LPS stimulation and decreased eosinophil production of IL-4, IL-8 and IL-13, but not IL-5. CONCLUSION AND CLINICAL RELEVANCE: Glucagon-like peptide-1 receptor is expressed on human eosinophils and neutrophils. A GLP-1 analog attenuates LPS-stimulated eosinophil activation. GLP-1 agonists may have additional adjunctive indications in treating persons with concomitant type 2 diabetes mellitus and asthma.

Nasal nitric oxide measurements in the assessment of nasal allergen challenge.

BACKGROUND: Several objective methods are used to assess the result of nasal allergen challenge. OBJECTIVE: The aim of this study was to compare the diagnostic value of nasal nitric oxide (nNO) measurements with that of peak nasal inspiratory flow (PNIF), nasal lavage fluid beta-tryptase levels, and changes in cell count after nasal challenge with grass pollen. METHODS: The study population comprised 24 patients allergic to grass pollen and 24 healthy controls. All participants underwent grass allergen challenge preceded by administration of placebo. A visual analog scale was administered. nNO and PNIF were determined, and nasal lavage fluid was collected before and 30 minutes after administration of placebo and allergen. The study was performed outside the pollen season. RESULTS: Significant changes in nNO, PNIF, nasal lavage fluid beta-tryptase level, and cell count were observed only in allergic patients after administration of the allergen. Receiver operating characteristic (ROC) curves were drawn for each determination. A change in nNO levels of -11.987% was indicated as the best cutoff point for differentiating between allergic patients and healthy participants with a sensitivity of 60.9%, specificity of 100%, negative predictive value of 71%, and positive predictive value of 100%. Comparison of the area under the ROC curve did not show significant differences between the diagnostic value of changes in nNO levels and other objective methods of assessing the outcome of the challenge. CONCLUSION: Changes in nNO levels do not differ significantly from other methods used to objectively assess the outcome of nasal challenge. Given their insufficient sensitivity, nNO measurements have limited value as the sole diagnostic tool when assessing the outcome of nasal challenge.

Differential expression of HSC73 and HSP72 mRNA and proteins between young and adult gerbils after transient cerebral ischemia: relation to neuronal vulnerability.

This study presents a quantitative comparison of the time courses and regional distribution of both constitutive HSC73 and inducible HSP72 mRNA expression and their respective encoded proteins between young (3-week-old) and adult (3-month-old) gerbil hippocampus after transient global ischemia. The constitutive expression of HSC73 mRNA and protein in the hippocampus of the young sham-operated gerbils was significantly higher than in the adults. The HSC73 mRNA expression after ischemia in the CA1 layer of young gerbils was greater than in adult gerbils. HSC73 immunoreactivity was not significantly changed after ischemia-reperfusion in adult hippocampus, whereas it decreased in young gerbils. Ischemia-reperfusion led to induction of HSP72 mRNA expression throughout the hippocampus of both young and adult gerbils. HSP72 mRNA induction was more intense and sustained in the CA1 subfield of young gerbils; this was associated with a marked induction of HSP72 proteins and neuronal survival. The transient expression of HSP72 mRNA in the CA1 layer of adult gerbils was not associated with a subsequent synthesis of HSP72 protein but was linked to neuronal loss. Expression of HSP72 mRNA was shifted to an earlier period of reflow in CA3 and dentate gyrus (DG) subfields of young animals. These findings suggest that the induction of both HSP72 mRNA and proteins in the CA1 pyramidal neurons of young gerbils, as well as the higher constitutive expression of HSC73, may partially contribute to higher neuronal resistance of young animals to transient cerebral ischemia.

Enzymatic and functional correction along with long-term enzyme secretion from transduced bone marrow hematopoietic stem/progenitor and stromal cells derived from patients with Fabry disease.

Fabry disease is a lysosomal storage disorder that is due to a deficiency in alpha-galactosidase A (alpha-gal A). Previously we have shown that a recombinant retrovirus synthesized for the transfer of the human alpha-gal A coding sequence was able to engineer enzymatic correction of the hydrolase deficiency in fibroblasts and lymphoblasts from Fabry patients. The corrected cells secreted alpha-gal A that was taken up and utilized by uncorrected bystander cells, thus demonstrating metabolic cooperativity. In separate experiments we used transduced murine bone marrow cells and successfully tested and quantitated this phenomenon in vivo. In the present studies, which were designed to bring this therapeutic approach closer to clinical utility, we establish that cells originating from the bone marrow of numerous Fabry patients and normal volunteers can be effectively transduced and that these target cells demonstrate metabolic cooperativity. Both isolated CD34+-enriched cells and long-term bone marrow culture cells, including nonadherent hematopoietic cells and adherent stromal cells, were transduced. The transferred gene generates increased intracellular alpha-gal A enzyme activity in these cells. Further, it causes functional correction of lipid accumulation and provides for long-term alpha-gal A secretion. Collectively, these results indicate that a multifaceted gene transfer approach to bone marrow cells may be of therapeutic benefit for patients with Fabry disease.

Interference by antiarrhythmic agents with function of electrical cardiac devices.

The possible interference of drugs with the function of implanted electrical cardiac devices in two patients is described, and the literature on the interaction between these drugs and devices is reviewed. A 59-year-old woman had a permanent pacemaker implanted after diagnosis of tachycardia-bradycardia syndrome, and her drug regimen of digoxin, verapamil, and warfarin was supplemented with flecainide to prevent paroxysmal atrial fibrillation. A Holter monitor recording performed after five days of flecainide therapy showed the pacemaker was sensing and pacing normally. Approximately three weeks after pacemaker implantation and initiation of flecainide therapy, a Holter monitor recording showed high-grade atrioventricular block and failure of the pacemaker to capture. A chest roentgenogram showed that the pacemaker lead was properly placed. The pacemaker's pulse amplitude and pulse width were increased, and the device again functioned reliably. Six months later the pacing threshold was noted to have returned to normal. A 64-year-old man had a history of aborted sudden cardiac death from ventricular tachyarrhythmias. The patient received an automatic implanted cardioverter-defibrillator (AICD); at that time, a 15-J discharge was required to terminate induced ventricular fibrillation (VF). Three years later, the AICD was replaced; the energy required for VF termination with the new unit was 16 J. Seven months after implantation of the new unit, the patient had several episodes of ventricular tachycardia (VT). Moricizine therapy was initiated. An electrophysiologic study (EPS) three days later showed that a larger shock (28 J) was required to terminate VF and that the pacing threshold had increased.(ABSTRACT TRUNCATED AT 250 WORDS)