Apical localization of zinc transporter ZnT4 in human airway epithelial cells and its loss in a murine model of allergic airway inflammation

The apical cytoplasm of airway epithelium (AE) contains abundant labile zinc (Zn) ions that are involved in the protection of AE from oxidants and inhaled noxious substances. A major question is how dietary Zn traffics to this compartment. In rat airways, in vivo selenite autometallographic (Se-AMG)-electron microscopy revealed labile Zn-selenium nanocrystals in structures resembling secretory vesicles in the apical cytoplasm. This observation was consistent with the starry-sky Zinquin fluorescence staining of labile Zn ions confined to the same region. The vesicular Zn transporter ZnT4 was likewise prominent in both the apical and basal parts of the epithelium both in rodent and human AE, although the apical pools were more obvious. Expression of ZnT4 mRNA was unaffected by changes in the extracellular Zn concentration. However, levels increased 3-fold during growth of cells in air liquid interface cultures and decreased sharply in the presence of retinoic acid. When comparing nasal versus bronchial human AE cells, there were significant positive correlations between levels of ZnT4 from the same subject, suggesting that nasal brushings may allow monitoring of airway Zn transporter expression. Finally, there were marked losses of both basally-located ZnT4 protein and labile Zn in the bronchial epithelium of mice with allergic airway inflammation. This study is the first to describe co-localization of zinc vesicles with the specific zinc transporter ZnT4 in airway epithelium and loss of ZnT4 protein in inflamed airways. Direct evidence that ZnT4 regulates Zn levels in the epithelium still needs to be provided. We speculate that ZnT4 is an important regulator of zinc ion accumulation in secretory apical vesicles and that the loss of labile Zn and ZnT4 in airway inflammation contributes to AE vulnerability in diseases such as asthma.

Bovine milk fat enriched in conjugated linoleic and vaccenic acids attenuates allergic airway disease in mice

Background: It has been argued that a reduction in the Western diet of anti-inflammatory unsaturated lipids, such as n-3 polyunsaturated fatty acids, has contributed to the increase in the frequency and severity of allergic diseases.

Objective: We investigated whether feeding milk fat enriched in conjugated linoleic acid and vaccenic acids (VAs) ('enriched' milk fat), produced by supplementing the diet of pasture-fed cows with fish and sunflower oil, will prevent development of allergic airway responses.

Methods: C57BL/6 mice were fed a control diet containing soybean oil and diets supplemented with milk lipids. They were sensitized by intraperitoneal injection of ovalbumin (OVA) on days 14 and 28, and challenged intranasally with OVA on day 42. Bronchoalveolar lavage fluid, lung tissues and serum samples were collected 6 days after the intranasal challenge.

Results: Feeding of enriched milk fat led to marked suppression of airway inflammation as evidenced by reductions in eosinophilia and lymphocytosis in the airways, compared with feeding of normal milk fat and control diet. Enriched milk fat significantly reduced circulating allergen-specific IgE and IgG1 levels, together with reductions in bronchoalveolar lavage fluid of IL-5 and CCL11. Treatment significantly inhibited changes in the airway including airway epithelial cell hypertrophy, goblet cell metaplasia and mucus hypersecretion. The two major components of enriched milk fat, cis-9, trans-11 conjugated linoleic acid and VA, inhibited airway inflammation when fed together to mice, whereas alone they were not effective.

Conclusion: Milk fat enriched in conjugated linoleic and VAs suppresses inflammation and changes to the airways in an animal model of allergic airway disease.

Tanis: a link between type 2 diabetes and inflammation?

Here we describe a novel protein, which we have named Tanis, that is implicated in type 2 diabetes and inflammation. In Psammomys obesus, a unique polygenic animal model of type 2 diabetes and the metabolic syndrome, Tanis is expressed in the liver in inverse proportion to circulating glucose (P = 0.010) and insulin levels (P = 0.004) and in direct proportion with plasma triglyceride concentrations (P = 0.007). Hepatic Tanis gene expression was markedly increased (3.1-fold) after a 24-h fast in diabetic but not in nondiabetic P. obesus. In addition, glucose inhibited Tanis gene expression in cultured hepatocytes (P = 0.006) as well as in several other cell types (P = 0.001–0.011). Thus, Tanis seems to be regulated by glucose and is dysregulated in the diabetic state. Yeast-2 hybrid screening identified serum amyloid A (SAA), an acute-phase inflammatory response protein, as an interacting protein of Tanis, and this was confirmed by Biacore experiments. SAA and other acute-phase proteins have been the focus of recent attention as risk factors for cardiovascular disease, and we contend that Tanis and its interaction with SAA may provide a mechanistic link among type 2 diabetes, inflammation, and cardiovascular disease.

What is "inflammation"? Are we ready to move beyond Celsus?

Inflammation, a term coined by the ancients, is widely used in sports medicine. But what is meant when a clinician tells a patient that symptoms are probably due to inflammation? The question of whether inflammation is helpful or harmful to healing can only be answered after inflammation is defined. This brief analysis of inflammation reveals that the term’s definition has changed dramatically since it was first used by Celsus nearly 2000 years ago. The definition also depends on the type of lens the viewer is using—whether it be clinical, cellular, or molecular.

What do we mean by the term "inflammation"? A contemporary basic science update for sports medicine

Most practicing sports medicine clinicians refer to the concept of "inflammation" many times a day when diagnosing and treating acute and overuse injuries. What is meant by this term? Is it a "good" or a "bad" process? The major advances in the understanding of inflammation in recent years are summarised, and some clinical implications of the contemporary model of inflammation are highlighted.

Markers of inflammation in South Asian and European infants from birth to 2 years in Manchester, UK

Inflammatory markers, including serum C-reactive protein (CRP), are predictors of coronary heart disease (CHD) in adults. South Asians in the UK have higher rates of CHD in adulthood than national rates.We tested the hypotheses that South Asian infants would have higher serum concentrations of CRP and homocysteine than European infants up to 2 years of age and that higher infant weight is associated with elevation of inflammatory markers. Infants of South Asian and European origin were investigated in a mixed cross sectional-longitudinal cohort study. Mothers were recruited ante-natally from St Mary’s Hospital,Manchester by postal invitation and telephone call to non-responders. Infants with metabolic or congenital abnormalities, known syndromes or pre-maturity were excluded. Measurements were collected at birth and either 3, 6, 12 or 24 months. High sensitivity CRP and homocysteine were measured by an immulite immunoassay. We used mixed linear modelling to assess whether infant weight, ethnicity, length of follow-up or their interaction were associated with inflammatory makers in infants during follow-up. Data are presented on 306 infants (109 South Asian and 197 European). We found that European infants had higher serum CRP than South Asian infants during follow-up which was of borderline significance.There was no difference in serum homocysteine between ethnic groups during followup and no significant interaction between ethnicity and follow-up. Infant weight was significantly associated with CRP but not homocysteine. In this ongoing longitudinal study,we found little difference in inflammatory markers in infants from birth to 2 years despite markedly higher rates of CHD in South Asian than European adults. Life course exposure to risk factors may play a more dominant role in the development of CHD.

Conjugated linoleic acid suppresses myogenic gene expression in a model of human muscle cell inflammation

Proinflammatory cytokines, such as tumor necrosis factor (TNF)-{alpha}, contribute to muscle wasting in inflammatory disorders, where TNF{alpha} acts to regulate myogenic genes. Conjugated linoleic acid (CLA) has shown promise as an antiproliferative and antiinflammatory agent, leading to its potential as a therapeutic agent in muscle-wasting disorders. To evaluate the effect of CLA on myogenesis during inflammation, human primary muscle cells were grown in culture and exposed to varying concentrations of TNF{alpha} and the cis-9, trans-11 and trans-10, cis-12 CLA isomers. Expression of myogenic genes (Myf5, MyoD, myogenin, and myostatin) and the functional genes creatine kinase (CK) and myosin heavy chain (MHC IIx) were measured by real-time PCR. TNF{alpha} significantly downregulated MyoD and myogenin expression, whereas it increased Myf5 expression. These changes corresponded with a decrease in both CK and MHC IIx expression. Both isomers of CLA mimicked the inhibitory effect of TNF{alpha} treatment on MyoD and myogenin expression, whereas myostatin expression was diminished in the presence of both isomers of CLA either alone or in combination with TNF{alpha}. Both isomers of CLA decreased CK and MHC IIx expression. These findings demonstrate that TNF{alpha} can have specific regulatory effects on myogenic genes in primary human muscle cells. A postulated antiinflammatory role of CLA in myogenesis appears more complex, with an indication that CLA may have a negative effect on this process.

Gender differences in muscle inflammation after eccentric exercise

Unaccustomed exercise is followed by delayed-onset muscle soreness and morphological changes in skeletal muscle. Animal studies have demonstrated that women have an attenuated response to muscle damage. We studied the effect of eccentric exercise in untrained male (n = 8) and female (n = 8) subjects using a unilateral exercise design [exercise (Ex) and control (Con) legs]. Plasma granulocyte counts [before (Pre) and 48 h after exercise (+48h)] and creatine kinase activity [Pre, 24 h after exercise (+24h), +48h, and 6 days after exercise (+6d)] were determined before (Pre) and after (+24h, +48h, +6d) exercise, with biopsies taken from the vastus lateralis of each leg at +48h for determination of muscle damage and/or inflammation. Plasma granulocyte counts increased for men and decreased for women at +48h (P < 0.05), and creatine kinase activity increased for both genders at +48h and +6d (P < 0.01). There were significantly greater areas of both focal (P < 0.001) and extensive (P < 0.01) damage in the Ex vs. Con leg for both genders, which was assessed by using toluidine blue staining. The number of leukocyte common antigen-positive cells/mm2 tissue increased with exercise (P < 0.05), and men tended to show more in their Ex vs. Con leg compared with women (P = 0.052). Men had a greater total (Ex and Con legs) number of bcl-2-positive cells/mm2 tissue vs. women (P < 0.05). Atrophic fibers with homogeneous bcl-2-positive staining were seen only in men (n = 3). We conclude that muscle damage is similar between genders, yet the inflammatory response is attenuated in women vs. men. Finally, exercise may stimulate the expression of proteins involved in apoptosis in skeletal muscle.

Skin prick test can identify eczematous infants at risk of asthma and allergic rhinitis

Background: Assessment of allergic sensitization is not routinely performed in infants and young children with eczema.

Objective: To determine whether infants who have atopic eczema (with sensitization) are at a greater risk of developing asthma and allergic rhinitis (AR) than those with non-atopic eczema (without concurrent sensitization).

Methods: The presence of eczema was prospectively documented until 2 years of age in a birth cohort of 620 infants with a family history of atopic disease. Sensitization status was determined by skin prick tests (SPTs) at 6, 12, and 24 months using six common allergens. Interviews were conducted at 6 and 7 years to determine the presence of asthma and AR.

Results: Within the first 2 years of life, 28.7% of the 443 children who could be classified had atopic eczema: 20.5% had non-atopic eczema, 19.0% were asymptomatic but sensitized and 31.8% were asymptomatic and not sensitized. When compared with children with non-atopic eczema in the first 2 years of life, children with atopic eczema had a substantially greater risk of asthma [odds ratio (OR)=3.52, 95% confidence interval=1.88–6.59] and AR (OR=2.91, 1.48–5.71). The increased risk of asthma was even greater if the infant had a large SPT (OR=4.61, 2.34–9.09) indicative of food allergy. There was no strong evidence that children with non-atopic eczema had an increased risk of asthma or AR compared with asymptomatic children.

Conclusion: In children with eczema within the first 2 years of life, SPT can provide valuable information on the risk of childhood asthma and AR.

The temporal sequence of allergic sensitization and onset of infantile eczema

Background: Eczema is commonly associated with sensitization in infants, but the causative role of sensitization in the development of eczema has been questioned.

Objective: To determine if allergic sensitization increases the risk of developing eczema, or alternatively, if eczema increases the risk of developing allergic sensitization.

Methods: We used data from the Melbourne Atopy Cohort Study, a prospective birth cohort of 552 infants with a family history of atopic disease. The main outcomes were risk of developing eczema from 6 months to 7 years of age in asymptomatic infants; and risk of developing sensitization, as measured by skin prick tests to milk, egg white, peanut, house dust mite, rye grass pollen and cat extracts, in previously unsensitized infants.

Results: Sensitization to food extracts at 6 months was associated with an increased risk of developing eczema [hazard ratio (HR) 1.63, 95% confidence interval 1.13–2.35] up to 7 years of age, after excluding infants with eczema in the first 6 months. However, eczema in the first 6 months was also associated with increased risk of new sensitization at both 1 year (HR 2.34, 1.38–3.98) and 2 years (HR 3.47, 1.65–7.32).

Conclusion: In some infants, sensitization precedes and predicts the development of eczema, while in others eczema precedes and predicts the development of sensitization. This indicates that there are multiple pathways to atopic eczema.

Associations between fatty acids in colostrum and breast milk and risk of allergic disease

Background Exposure to n-3 polyunsaturated fatty acids (PUFA) in early life is hypothesized to offer protection against atopic disease. However, there is controversy in this area, and we have previously observed that high levels of n-3 fatty acid (FA) in colostrum are associated with increased risk of allergic sensitization.
Objective The aim of the study was to assess the relationship between FA profile in breast milk and risk of childhood atopic disease.
Methods A high-risk birth cohort was recruited, and a total of 224 mothers provided a sample of colostrum (n = 194) and/or 3-month expressed breast milk (n = 118). FA concentrations were determined by gas chromatography. Presence of eczema, asthma and rhinitis were prospectively documented up to 7 years of age.
Results High levels of n-3 22:5 FA (docosapentaenoic acid, DPA) in colostrum were associated with increased risk of infantile atopic eczema [odds ratio (OR) = 1.66 per 1 standard deviation increase, 95% confidence interval (CI) = 1.11–2.48], while total n-3 concentration in breast milk was associated with increased risk of non-atopic eczema (OR = 1.60, 95% CI = 1.03–2.50). Higher levels of total n-6 FA in colostrum were associated with increased risk of childhood rhinitis (OR = 1.59, 95% CI = 1.12–2.25). There was no evidence of associations between FA profile and risk of asthma.
Conclusion In this cohort of high-risk children, a number of modest associations were observed between FA concentrations in colostrum and breast milk and allergic disease outcomes. Further research in this area with larger sample sizes is needed.

An aqueous Chlorella extract inhibits IL-5 production by mast cells in vitro and reduces ovalbumin-induced eosinophil infiltration in the airway in mice in vivo

An aqueous extract of the edible microalga, Chlorella pyrenoidosa (CP) (1), has recently been tested for its immunomodulatory effects in a human clinical trial. Here, the CP extract was dialyzed and fractionated using Sephadex G 100 chromatography. The effects of a dialyzed aqueous CP extract, fraction 2, on mast cell mediator release in vitro and ovalbumin-induced allergic airway inflammation in vivo were examined. In vitro, treatment of mouse bone marrow-derived mast cells with 2 for 18 h significantly inhibited antigen (trinitrophenyl-BSA)-induced IL-5 production. In vivo, treatment of mice with 2 during ovalbumin sensitization and stimulation process significantly reduced eosinophil and neutrophil infiltration in the airways. Moreover, fractions obtained by size exclusion chromatography of 2 inhibited IgE-dependent cytokine GM-CSF production from human cord blood-derived mast cells. Taken together, these results suggest that 2 is composed of biopolymers with anti-allergic potential.

Simultaneous neuroprotection and blockade of inflammation reverses autoimmune encephalomyelitis

In multiple sclerosis, the immune system attacks the white matter of the brain and spinal cord, leading to disability and/or paralysis. Myelin, oligodendrocytes and neurons are lost due to the release by immune cells of cytotoxic cytokines, autoantibodies and toxic amounts of the excitatory neurotransmitter glutamate. Experimental autoimmune encephalomyelitis (EAE) is an animal model that exhibits the clinical and pathological features of multiple sclerosis. Current therapies that suppress either the inflammation or glutamate excitotoxicity are partially effective when administered at an early stage of EAE, but cannot block advanced disease. In a multi-faceted approach to combat EAE, we blocked inflammation with an anti-MAdCAM-1 (mucosal addressin cell adhesion molecule-1) monoclonal antibody and simultaneously protected oligodendrocytes and neurons against glutamate-mediated damage with the -amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainate antagonist 2,3-dihydroxy-6-nitro-7- sulfamoylbenzo(f)quinoxaline (NBQX) and the neuroprotector glycine–proline–glutamic acid (GPE; N-terminal tripeptide of insulin-like growth factor). Remarkably, administration at an advanced stage of unremitting EAE of either a combination of NBQX and GPE, or preferably all three latter reagents, resulted in amelioration of disease and repair of the CNS, as assessed by increased oligodendrocyte survival and remyelination, and corresponding decreased paralysis, inflammation, CNS apoptosis and axonal damage. Each treatment reduced the expression of nitric oxide and a large panel of proinflammatory and immunoregulatory cytokines, in particular IL-6 which plays a critical role in mediating EAE. Mice displayed discernible improvements in all physical features examined. Disease was suppressed for 5 weeks, but relapsed when treatment was suspended, suggesting treatment must be maintained to be effective. The above approaches, which allow CNS repair by inhibiting inflammation and/or simultaneously protect neurons and oligodendrocytes from damage, could thus be effective therapies for multiple sclerosis.

Inflammation, hepatic enzymes and resistance training in individuals with metabolic risk factors

Aims Increases in inflammatory markers, hepatic enzymes and physical inactivity are associated with the development of the metabolic syndrome (MetS). We examined whether inflammatory markers and hepatic enzymes are correlated with traditional risk factors for MetS and studied the effects of resistance training (RT) on these emerging risk factors in individuals with a high number of metabolic risk factors (HiMF, 2.9 ± 0.8) and those with a low number of metabolic risk factors (LoMF, 0.5 ± 0.5).

Methods Twenty-eight men and 27 women aged 50.8 ± 6.5 years (mean ± sd) participated in the study. Participants were randomized to four groups, HiMF training (HiMFT), HiMF control (HiMFC), LoMF training (LoMFT) and LoMF control (LoMFC). Before and after 10 weeks of RT [3 days/week, seven exercises, three sets with intensity gradually increased from 40–50% of one repetition maximum (1RM) to 75–85% of 1RM], blood samples were obtained for the measurement of pro-inflammatory cytokines, C-reactive protein (CRP), -glutamyltransferase (GGT) and alanine aminotransferase (ALT).

Results At baseline, HiMF had higher interleukin-6 (33.9%), CRP (57.1%), GGT (45.2%) and ALT (40.6%) levels, compared with LoMF (all P < 0.05). CRP, GGT and ALT correlated with the number of risk factors (r = 0.48, 0.51 and 0.57, respectively, all P < 0.01) and with other anthropometric and clinical measures (r range from 0.26 to 0.60, P < 0.05). RT did not significantly alter inflammatory markers or hepatic enzymes (all P > 0.05).

Conclusions HiMF was associated with increased inflammatory markers and hepatic enzyme concentrations. RT did not reduce inflammatory markers and hepatic enzymes in individuals with HiMF.