Effect of aging on sputum inflammation and asthma control.

BACKGROUND: Aged asthmatic patients experience increased morbidity and mortality. Knowledge of the aging effect on airway inflammation and asthma control is limited. OBJECTIVE: We sought to compare airway inflammation and its relationship to asthma control in aged versus younger patients and determine whether differences are asthma specific or caused by "inflamm-aging." METHODS: We performed a prospective study of aged (>60 years) and younger (21-40 years) inner-city patients with asthma. After a run-in period to control for inhaled corticosteroid use, induced sputum was collected. Age-matched nonasthmatic control subjects were included to measure age-related inflammatory changes. RESULTS: Aged (mean age, 67.9 ± 5.1 years; n = 35) compared with younger (mean age, 30.8 ± 5.9 years; n = 37) asthmatic patients had significantly worse asthma control and lower FEV1. Aged asthmatic patients had higher sputum neutrophil (30.5 × 104/mL and 23.1%) and eosinophil (7.0 × 104/mL and 3.8%) numbers and percentages compared with younger patients (neutrophils, 13.0 × 104/mL [P < .01] and 6.9% [P < .01]; eosinophils, 2.0 × 104/mL [P < .01] and 1.2% [P < .01]). Aged asthmatic patients had higher sputum IL-6 (P < .01) and IL-8 (P = .01) levels. No significant inflammatory differences between aged and younger control subjects were observed. In aged asthmatic patients increased sputum IL-6 and macrophage inflammatory protein 3α/CCL20 levels were significantly associated with decreased asthma control and increased sputum neutrophil numbers and IL-1ß, IL-6, and macrophage inflammatory protein 3α/CCL20 levels were associated with hospitalization. CONCLUSIONS: The inflammatory patterns of aged versus younger asthmatic patients are associated with increased sputum neutrophil and eosinophil values and cytokine levels related to neutrophil recruitment. Differences in airway inflammation can contribute to diminished asthma control in the aged. Further understanding of asthma pathophysiology in aged patients is needed to improve management of this vulnerable population.

The effect of estrogen-containing birth control pills on the constituents of bradykinin expression in plasma.

Background: Hereditary angioedema with C1-inhibitor deficiency (HAE-C1INH) is a rare autosomal disorder presenting with recurrent angioedema. Estrogen-containing medications trigger angioedema in some patients, and conversely, progesterone may decrease attack frequency. The mechanism by which estrogen may exacerbate angioedema in HAE-C1INH is not well characterized. Objective: Our aim was to investigate the link between estrogen and bradykinin constituents to better understand the specific underlying triggers that may exacerbate angioedema in patients with HAE-C1INH. Methods: As estrogen is contraindicated for patients with HAE-C1INH, females without a history of angioedema were recruited to evaluate whether estrogen-containing oral contraceptive pills (OCPs) alter plasma protein levels of bradykinin, cleaved high-molecular-weight kininogen (cHK), and activated factor XII (FXIIa). Blood (plasma) was collected before initiation of OCP administration and 3 months thereafter. High-molecular-weight kininogen (HK) was measured by ELISA and FXIIa and cHK were analyzed by Western blot analysis. Results: A total of 12 adult females without HAE-CINH (aged <40 years) had a median baseline plasma HK level of 33,976 ng/mL. After 3 months of OCP therapy, their median HK level increased to 38,202 ng/mL. With OCPs, there was also a significant increase in level of FXIIa protein (P <.01), as well as an increase in cHK protein level. Conclusion: This preliminary study, performed in females without HAE-C1INH, suggests that estrogen may exacerbate angioedema by increasing the production of cHK and FXIIa.

Inflammatory markers in world trade center workers with asthma: Associations with post traumatic stress disorder.

BACKGROUND: Post-traumatic stress disorders (PTSD) is associated with worse asthma outcomes in individuals exposed to the World Trade Center (WTC) site. RESEARCH QUESTION: Do WTC workers with coexisting PTSD and asthma have a specific inflammatory pattern that underlies the relationship with increased asthma morbidity? STUDY DESIGN AND METHODS: We collected data on a cohort of WTC workers with asthma recruited from the WTC Health Program. Diagnosis of PTSD was ascertained with a Structured Clinical Interview for DSM-5 (Diagnostic and Statistical Manuel of Mental Disorders) and the severity of PTSD symptoms was assessed with the PTSD Checklist 5. We obtained blood and sputum samples to measure cytokines levels in study participants. RESULTS: Of the 232 WTC workers with diagnosis of asthma in the study, 75 (32%) had PTSD. PTSD was significantly associated with worse asthma control (p = 0.002) and increased resource utilization (p = 0.0002). There was no significant association (p>0.05) between most blood or sputum cytokines with PTSD diagnosis or PCL-5 scores both in unadjusted and adjusted analyses. INTERPRETATION: Our results suggest that PTSD is not associated with blood and sputum inflammatory markers in WTC workers with asthma. These findings suggest that other mechanisms likely explain the association between PTSD and asthma control in WTC exposed individuals.

The effect of oral tolerance on the allergic airway response in younger and aged mice.

BACKGROUND: The effect of increased age on the induction of oral tolerance by low-dose antigen feeding and its effect on the response to antigen airway challenge in aged mice have not been well characterized. OBJECTIVE: To determine whether oral tolerance can be induced in aged mice and its impact on the development of allergic airway inflammation. METHODS: Younger (6 weeks old) and aged (18 months old) mice were fed ovalbumin (OVA) prior to sensitization to induce antigen tolerance. Serum antigen-specific immunoglobulins (Igs), bronchoalveolar lavage fluid (BALF), lung histology, enumeration of CD4 + Foxp3+ Treg cells, and airway hyperresponsiveness (AHR) were determined after the final antigen challenge. RESULTS: Feeding antigen to aged mice prior to sensitization induced oral tolerance as determined by a decrease in antigen-specific IgE and IgG(1); however, the effect was greater in younger mice. Induction of oral tolerance was associated with a greater increase in airway Treg cells in the younger mice. Despite these differences, oral tolerance significantly suppressed features of asthma in aged mice, including BALF total cell and eosinophil numbers, cytokine production, and AHR. CONCLUSIONS: Aged mice developed oral tolerance to antigen, which suppressed several features of allergic airway inflammation.

The Effect of Age on T-Regulatory Cell Number and Function in Patients With Asthma.

T-regulatory cells (Tregs) play a key role in suppressing effector cells and maintaining self-tolerance. Studies of younger adults and children suggest that insufficient differentiation and functional defects of Tregs may contribute to the development of asthma; however, data from older patients with asthma are limited. To address the effects of aging on the relationship of Treg frequency and function with clinical outcomes, we collected induced sputum (differential cell count and Treg frequency) and peripheral blood (Treg function and frequency) from aged (> 60 years of age) and younger (20-40 years old) patients with asthma. In younger patients, low Treg suppression was associated with significantly higher mean numbers of emergency department (ED) (1.8 vs. 0.17, P = 0.02) and urgent care visits (2.3 vs. 0.17, P = 0.01) for asthma, and decreased asthma control (mean Asthma Control Test [ACT] score, 17 vs. 21.3, P = 0.01) compared to those with high Treg suppression. In older patients, however, a lower Treg function was not significantly associated with ACT scores (18.2 vs. 13.4, P = 0.10), or the number of ED (P = 0.9) or urgent care visits (P = 0.2). Our data suggest that Tregs have a weak relationship with asthma control and clinical asthma outcomes in older patients and differ from findings in younger patients, where Tregs are more likely to play a protective role.

Adipokine regulation of colon cancer: adiponectin attenuates interleukin-6-induced colon carcinoma cell proliferation via STAT-3.

Obesity results in increased circulating levels of specific adipokines, which are associated with colon cancer risk. The disease state is associated with increased leptin, insulin, IGF-1, and IL-6. Conversely, adiponectin levels are decreased in obese individuals. Previously, we demonstrated adipokine-enhanced cell proliferation in preneoplastic, but not normal, colon epithelial cells, demonstrating a differential effect of adipokines on colon cancer progression in vitro. Using a model of late stage carcinoma cancer cell, namely murine MC-38 colon carcinoma cells, we compared the effect of obesity-associated adipokines (leptin, insulin, IGF-1, and IL-6) on MC-38 cell proliferation and determined whether adiponectin (full length or globular) could modulate adipokine-induced cell proliferation. We show that insulin and IL-6, but not leptin and IGF-1, induce proliferation in MC-38 cells. Adiponectin treatment of MC-38 cells did not inhibit insulin-induced cell proliferation but did inhibit IL-6-induced cell proliferation by decreasing STAT-3 phosphorylation and activation. Nitric oxide (NO) production was increased in MC-38 cells treated with IL-6; co-treatment with adiponectin blocked IL-6-induced iNOS and subsequent NO production. These data are compared to previously reported findings from our laboratory using the YAMC (model normal colon epithelial cells) and IMCE (model preneoplastic) cells. The cell lines are utilized to construct a model summarizing the hormonal consequences of obesity and the impact on the differential regulation of colon epithelial cells along the continuum to carcinoma. These data, taken together, highlight mechanisms involved in obesity-associated cancers and may lead to potential-targeted therapies.

Novel mechanism for obesity-induced colon cancer progression.

Adipose tissue secretes factors linked to colon cancer risk including leptin. A hallmark of cancer is sustained angiogenesis. While leptin promotes angiogenesis in adipose tissue, it is unknown whether leptin can induce epithelial cells to produce factors that may drive angiogenesis, vascular development and therefore cancer progression. The purpose of this study was to compare the effects of leptin-stimulated colon epithelial cells differing in adenomatous polyposis coli (Apc) genotype (gatekeeper tumor suppressor gene for colon cancer) on angiogenesis. We employed novel colonic epithelial cell lines derived from the Immorto mouse [young adult mouse colon (YAMC)] and the Immorto-Min mouse [Immorto-Min colonic epithelial cell (IMCE)], which carries the Apc Min mutation, to study the effects of leptin-stimulated colon epithelial cells on angiogenesis. We utilized ex vivo rat mesenteric capillary bioassay and human umbilical vein endothelial cell (HUVEC) models to study angiogenesis. IMCE cells stimulated with leptin produced significantly more vascular endothelial growth factor (VEGF) than YAMC (268 +/- 18 versus 124 +/- 8 pg/ml; P < 0.01) cells. Leptin treatment induced dose-dependent increases in VEGF only in IMCE cells. Conditioned media from leptin (50 ng/ml)-treated IMCE cells induced significant capillary formation compared with control, which was blocked by the addition of a neutralizing antibody against VEGF. Conditioned media from leptin-treated IMCE cells also induced HUVEC cell proliferation, chemotaxis, upregulation of adhesion proteins and cell-signaling activation resulting in nuclear factor kappa B nuclear translocation and DNA binding due to VEGF. This is the first study demonstrating that leptin can induce preneoplastic colon epithelial cells to orchestrate VEGF-driven angiogenesis and vascular development, thus providing a specific mechanism and potential target for obesity-associated cancer.

Adiponectin blocks multiple signaling cascades associated with leptin-induced cell proliferation in Apc Min/+ colon epithelial cells.

We previously demonstrated that leptin, an adipose-derived hormone, induces cell proliferation in a model of preneoplastic (IMCE (Apc(Min/+)), but not normal (YAMC (Apc(+/+)), colon epithelial cells by inducing autocrine IL-6 production and trans-IL-6 signaling. Low serum adiponectin is associated with colon, prostate and breast cancer. Adiponectin is secreted by white adipose tissue; the levels of adiponectin in the blood decrease as body mass index (and leptin) increases. In our study, we tested whether murine recombinant globular adiponectin (gArcp30) could modulate leptin-induced cell proliferation, autocrine IL-6 production, trans-IL-6 signaling and other leptin-induced cell signaling events previously observed in IMCE cells but not YAMC cells. Under serum-free conditions, adiponectin (1 mug/ml) inhibited leptin-induced autocrine IL-6 production, soluble IL-6 receptor shedding, trans-IL-6 signaling and subsequent STAT3 phosphorylation in IMCE cells. Adiponectin inhibited leptin-induced cell proliferation in the IMCE cells and this inhibition was associated with I kappa B-alpha phosphorylation, I kappa B-alpha degradation and decreased NF-kappaB p65 DNA activation and binding. These data indicate that adiponectin acts on preneoplastic colon epithelial cells to regulate cell growth via 2 distinct pathways inhibiting leptin-induced NF-kappaB-dependent autocrine IL-6 production and trans-IL-6 signaling. We hypothesize that adiponectin may be an important regulator of colon epithelial cell homeostasis by linking the observed reduced risk for cancer in populations with high serum adiponectin concentrations to specific mechanisms of cell number homeostasis in a model of preneoplastic colon epithelial cells. These data may have broad implications for diet and lifestyle strategies for the prevention and treatment of obesity-associated cancers.