Genetic association between the APOE ε4 allele, toxicant exposures and Gulf war illness diagnosis

INTRODUCTION

Exposure to nerve agents, pyridostigmine bromide (PB), pesticides, and oil-well fires during the 1991 Gulf War (GW) are major contributors to the etiology of Gulf War Illness (GWI). Since the apolipoprotein E (APOE) ε4 allele is associated with the risk of cognitive decline with age, particularly in the presence of environmental exposures, and cognitive impairment is one of the most common symptoms experienced by veterans with GWI, we examined whether the ε4 allele was associated with GWI.

METHODS

Using a case-control design, we obtained data on APOE genotypes, demographics, and self-reported GW exposures and symptoms that were deposited in the Boston Biorepository and Integrative Network (BBRAIN) for veterans diagnosed with GWI (n = 220) and healthy GW control veterans (n = 131). Diagnosis of GWI was performed using the Kansas and/or Center for Disease Control (CDC) criteria.

RESULTS

Age- and sex-adjusted analyses showed a significantly higher odds ratio for meeting the GWI case criteria in the presence of the ε4 allele (Odds ratio [OR] = 1.84, 95% confidence interval [CI = 1.07-3.15], p ≤ 0.05) and with two copies of the ε4 allele (OR = 1.99, 95% CI [1.23-3.21], p ≤ 0.01). Combined exposure to pesticides and PB pills (OR = 4.10 [2.12-7.91], p ≤ 0.05) as well as chemical alarms and PB pills (OR = 3.30 [1.56-6.97] p ≤ 0.05) during the war were also associated with a higher odds ratio for meeting GWI case criteria. There was also an interaction between the ε4 allele and exposure to oil well fires (OR = 2.46, 95% CI [1.07-5.62], p ≤ 0.05) among those who met the GWI case criteria.

CONCLUSION

These findings suggest that the presence of the ε4 allele was associated with meeting the GWI case criteria. Gulf War veterans who reported exposure to oil well fires and have an ε4 allele were more likely to meet GWI case criteria. Long-term surveillance of veterans with GWI, particularly those with oil well fire exposure, is required to better assess the future risk of cognitive decline among this vulnerable population.

Boston biorepository, recruitment and integrative network (BBRAIN): A resource for the Gulf War Illness scientific community

AIMS

Gulf War Illness (GWI), a chronic debilitating disorder characterized by fatigue, joint pain, cognitive, gastrointestinal, respiratory, and skin problems, is currently diagnosed by self-reported symptoms. The Boston Biorepository, Recruitment, and Integrative Network (BBRAIN) is the collaborative effort of expert Gulf War Illness (GWI) researchers who are creating objective diagnostic and pathobiological markers and recommend common data elements for GWI research.

MAIN METHODS

BBRAIN is recruiting 300 GWI cases and 200 GW veteran controls for the prospective study. Key data and biological samples from prior GWI studies are being merged and combined into retrospective datasets. They will be made available for data mining by the BBRAIN network and the GWI research community. Prospective questionnaire data include general health and chronic symptoms, demographics, measures of pain, fatigue, medical conditions, deployment and exposure histories. Available repository biospecimens include blood, plasma, serum, saliva, stool, urine, human induced pluripotent stem cells and cerebrospinal fluid.

KEY FINDINGS

To date, multiple datasets have been merged and combined from 15 participating study sites. These data and samples have been collated and an online request form for repository requests as well as recommended common data elements have been created. Data and biospecimen sample requests are reviewed by the BBRAIN steering committee members for approval as they are received.

SIGNIFICANCE

The BBRAIN repository network serves as a much needed resource for GWI researchers to utilize for identification and validation of objective diagnostic and pathobiological markers of the illness.

Fluticasone alone or in combination with salmeterol vs triamcinolone in asthma

OBJECTIVES

To compare the efficacies of medium-dose fluticasone propionate (FP), medium-dose triamcinolone acetonide (TAA), and combined low-dose FP plus salmeterol (SL).

DESIGN

Randomized, double-blind, triple-dummy, multicenter, 12-week clinical trial.

SETTING

Allergy/respiratory care clinics.

PATIENTS

Six hundred eighty patients with asthma previously uncontrolled with low-dose inhaled corticosteroids.

INTERVENTIONS

FP, 220 microg bid; TAA, 600 microg bid; or FP, 88 microg plus SL, 42 microg bid.

MEASUREMENTS AND RESULTS

Outcome measures included FEV1, peak expiratory flow (PEF), supplemental albuterol use, nighttime awakenings, asthma symptoms, and physician global assessment. Compared with TAA, 600 microg bid, treatment with FP 220, microg bid, significantly increased FEV1, morning and evening PEF, and percent symptom-free days, and significantly reduced rescue albuterol use, number of nighttime awakenings, and overall asthma symptom scores (p < or = 0.035). Improvements with low-dose FP, 88 microg, plus SL, 42 microg bid, were significantly (p < or = 0.004) greater than TAA, 600 microg bid, in all the aforementioned efficacy measures as well as percent of rescue-free days. Combined low-dose FP, 88 microg, plus SL, 42 microg bid, also significantly increased FEV1 and percent of rescue-free days, and significantly reduced albuterol use compared with medium-dose FP, 220 microg bid (p < or = 0.018). At endpoint, both FP, 220 microg bid, and FP, 88 microg, plus SL, 42 microg bid, significantly increased FEV1 by 0.48 L and 0.58 L, respectively, compared with 0.34 L with TAA, 600 microg bid.

CONCLUSION

In patients who are symptomatic while taking low-dose inhaled corticosteroids, medium-dose FP (440 microg/d) and combination treatment with low-dose FP (176 microg/d) plus SL (84 microg/d) are both more effective than medium-dose TAA (1200 microg/d) in improving pulmonary function and asthma symptom control.

CFTR antisense phosphorothioate oligodeoxynucleotides (S-ODns) induce tracheo-bronchial mucin (TBM) mRNA expression in human airway mucosa

Mucus hypersecretion is a critical component of cystic fibrosis (CF) pathogenesis. The effects of dysfunction of the cystic fibrosis transmembrane regulator (CFTR) on mucin expression were examined using the tracheo-bronchial mucin (TBM) gene as an indicator. TBM mRNA expression was assessed in a human bronchial epithelial cell line (HBE1) and human nasal mucosal explants in vitro. Antisense phosphorothioate oligodeoxynucleotides (S-ODN) to TBM suppressed baseline expression of TBM mRNA in both systems, but had no effect on glyceraldehyde phosphate dehydrogenase mRNA (GAPDH) expression. Sense and missense (multiple scrambled control oligonucleotides) S-ODNs had no effect. 8Br-cAMP and PGE1 significantly elevated TBM mRNA expression. These increases were also specifically inhibited by the antisense S-ODNs. In order to induce a CF-like state, S-ODN to CFTR were added to explants. Antisense CFTR S-ODNs were anticipated to reduce the expression of cellular CFTR protein, and the level of CFTR function. Antisense, but not sense or missense, CFTR S-ODN significantly increased TBM mRNA expression. These data suggest that mucin hypersecretion in CF may be a direct consequence of CFTR dysfunction; the specific mechanism through which this effect is mediated is not known.

Endothelin in human nasal mucosa

Endothelin (ET), a potent vasoconstrictor and bronchoconstrictor peptide synthesized by endothelial and epithelial cells, was examined for its potential functions in human inferior turbinate nasal mucosal tissue by four techniques: (1) immunoreactive ET was localized in the mucosa by immunohistochemistry; (2) receptors for ET were identified by autoradiography employing [125I]ET; (3) ET-1 mRNA was localized by in situ hybridization; and (4) the secretory functions of ET were examined by the release of mucous and serous cell products after the addition of ET to human nasal turbinates in short-term cultures. Specific ET-1-immunoreactive material was found most extensively in small muscular arteries and in serous cells in submucosal glands. ET-1 was also found to a lower extent in the walls of venous sinusoids. [125I]ET-1 binding sites were localized by autoradiography to submucosal glands and to venous sinusoids and small muscular arterioles. mRNA for ET-1 was found most extensively in the venous sinusoids and to a lesser extent in small muscular arteries. In mucosal explant cultures, ET-1 and ET-2 stimulated lactoferrin and mucous glycoprotein release from serous and mucous cells, but ET-3 was inactive. The observations indicate that in the human nasal mucosa, ET is present in the vascular endothelium and the serous cells in submucosal glands and acts on glandular ET receptors to induce both serous and mucous cell secretion. It is also likely that ET plays a role in the regulation of vasomotor tone.

Bronchoconstriction and airway microvascular leakage in guinea pigs sensitized with trimellitic anhydride

We have developed a guinea pig model of immediate airway responses following intradermal sensitization with free trimellitic anhydride (TMA). Guinea pigs were given an intradermal injection with either 0.1 ml of 0.3% TMA in corn oil (n = 8) or 0.1 ml of corn oil alone (n = 6). A guinea pig serum albumin conjugate of trimellitic anhydride (TMA-GPSA) was prepared with a substitution ratio of 21:1. All sensitized guinea pigs had raised specific serum IgG1 antibodies (ELISA), and IgE antibodies were detected in six of the eight sensitized guinea pigs by passive cutaneous anaphylaxis. On Days 21 to 28, guinea pigs were anesthetized, tracheostomized, and ventilated. Evans blue dye (20 mg/ml), an albumin marker, was injected intravenously to quantify airway microvascular leakage (MVL). TMA-GPSA (50 microliters; 1%) in saline was instilled into the trachea. Lung resistance (RL) was measured for 6 min. The guinea pigs were killed, and the lungs were removed. Peak RL (cm H2O/ml x s-1) was significantly increased in sensitized guinea pigs from 0.26 +/- 0.01, mean +/- SEM to 21.3 +/- 6.9 (p < 0.05), compared with nonsensitized guinea pigs. There was a significant increase in Evans blue at all levels of the tracheobronchial tree in sensitized guinea pigs compared with the controls (p < 0.005). The site of MVL was localized to the postcapillary venules as assessed by extravasation of intravascular Monastral blue dye. We conclude that intradermal sensitization of guinea pigs to TMA induces a polyclonal immune response, associated with bronchoconstriction and airway microvascular leakage, when challenged specifically with TMA-GPSA.(ABSTRACT TRUNCATED AT 250 WORDS)

Eosinophil cationic protein stimulates and major basic protein inhibits airway mucus secretion

Possible roles of eosinophil (EO) products in modulating the release of mucus from airway explants were investigated. Cell- and membrane-free lysates from purified human EOs (1 to 20 x 10(5)) caused a dose-dependent release of respiratory glycoconjugates (RGC) from cultured feline tracheal explants. Crude extracts from isolated EO granules also stimulated RGC release, suggesting that a granular protein might be responsible. Three proteins derived from EO granules, EO-derived neurotoxin, EO cationic protein (ECP), and major basic protein (MBP) were separated by sequential sizing and affinity chromatography. ECP (0.025 to 25 micrograms/ml) caused a dose-dependent increase in RGC release from both feline and human airway explants and also stimulated the release of the serous cell-marker, lactoferrin, from human bronchial explants. EO-derived neurotoxin (0.025 to 50 micrograms/ml) failed to affect RGC release, whereas MBP (50 micrograms/ml) significantly inhibited RGC release from feline explants. Thus, ECP stimulates RGC and lactoferrin release from airway explants, whereas MBP inhibits RGC release.