A multi-hit endocrine model of intrinsic adult-onset asthma

Sex and gender in respiratory physiology

Sex is a biological concept determined at conception. Gender is a social concept. Medicine recognises sex as a biological variable and recommends including sex as a factor in clinical practice norms and as a topic of bench and clinical research. Sex plays a role in respiratory physiology according to two pathways: hormones and anatomy, with females characterised by smaller dimensions at every level of the respiratory system. Sex hormones also play specific roles in lung inflammatory processes, breathing control and in response to diseases. The literature is extremely controversial because many factors need to be considered to avoid erroneous comparisons. The main difficulty lies in creating homogeneous groups of subjects according to age, body weight, lung/airway size, fluctuations in circulating hormone levels, and exercise protocol. Because almost all of the knowledge available in physiology is based on research in males, medicine for women is therefore less evidence-based than that being applied to men. Finally, the number of transsexual people is increasing and they represent new challenges for clinicians, due to the anatomical and physiological changes that they undergo.

Endocrine regulation of lung disease and inflammation

IMPACT STATEMENT

Sex-differences in the incidence and severity of inflammatory lung diseases have been recognized for years. Women of reproductive age are more likely to suffer from chronic lung disease, with higher mortality rates than men. Physiological changes in hormone levels such as those occurring during the menstrual cycle, pregnancy, and menopause have been associated with lung function changes and asthma symptoms. Despite this, the roles of sex hormones in the mechanisms associated with lung diseases have not been fully elucidated. This review summarizes basic and clinical studies of sex hormones as potential modulators of lung function and inflammation. The information obtained from sex-specific research on lung physiology and pathology will potentially help in the development of sex-specific therapeutics for inflammatory lung disease that may account for the hormonal status of the patient.

New-Onset Asthma in Adults: What Does the Trigger History Tell Us?

BACKGROUND

Adult-onset asthma is an important asthma phenotype and, in contrast to childhood asthma, is often associated with specific triggers of onset. It is unknown whether these triggers correspond with specific phenotypic characteristics or predict a specific asthma outcome.

OBJECTIVE

To compare clinical, functional, and inflammatory characteristics between patients with different triggers of asthma onset, and relate these triggers to asthma outcome.

METHODS

Two hundred adults with recently diagnosed (<1 year) asthma were prospectively followed for 5 years. The trigger of asthma onset was patient reported and defined by the question: "What, in your opinion, elicited your asthma?" Asthma remission was defined as no asthma symptoms and no asthma medication use for ≥1 year. Kruskal-Wallis and Fisher's exact test were used to compare categories containing >10 patients.

RESULTS

Ten categories of triggers were identified, of which 5 contained >10 patients. Clinical and inflammatory characteristics and remission rates differed significantly between categories. "New allergic sensitization" (11%) was associated with mild atopic asthma and a relatively young age at onset; "pneumonia" (8%) with previous smoking, low IgE, and the highest remission rates (one third); "upper respiratory symptoms" (22%) with high exhaled NO and eosinophilia; "no trigger identified" (38%) did not show any specific characteristics; and "stressful life event" (7%) with high medication usage, low type 2 markers, and no disease remission.

CONCLUSIONS

Patients with adult-onset asthma can be characterized by the trigger that seemingly incited their asthma. These triggers might represent underlying mechanisms and may be important to phenotype patients and predict disease outcome.

Cerebral anatomical changes in female asthma patients with and without depression compared to healthy controls and patients with depression

BACKGROUND

Population-based studies have demonstrated that asthma patients with depression symptoms are more likely to have poor asthma control and worse asthma outcomes. However, the underlying mechanism of the relationship between asthma and depression is still unclear. The present study aimed to examine the cerebral anatomical changes in female asthma patients with and without depression.

METHODS

Using structural magnetic resonance imaging (MRI) and a voxel-based morphometry technique, the primary effects of and the interaction between asthma and depression were analyzed. The cerebral gray matter volume (GMV) was compared between the groups. Correlation analyses between the GMV value of the brain regions and the clinical parameters were completed.

RESULTS

The interaction effect of asthma and depression was found on the right superior temporal gyrus (STG) and the left middle temporal gyrus. Patients with both asthma and depression showed less GMV in the right STG, the bilateral precuneus, and the right superior frontal gyrus compared to patients with asthma only. The GMV of the right STG showed a decrement form among the asthma only group, healthy controls and asthma plus depression group. In patients with asthma and depression, the volume of the right STG was positively correlated with PD20 (r = 0.714, p = 0.047) and negatively correlated with the nocturnal awakening score in the Asthma Control Test (r = -0.061, p = 0.038).

CONCLUSION

Current findings provided convergent evidence to support the critical role of the right STG in the brain mechanism that mediates asthma and depression.

Macrophage colony stimulating factor and monocyte chemoattractant protein 2 are elevated in intrinsic asthmatics

BACKGROUND

Intrinsic asthma, etiology unknown, occurs later in life, mostly in females. It is associated with nasal polyps and massive eosinopillic infiltration of the respiratory mucous membrane, aspirin intolerance and steroid dependence. The aim of the study was to determine the cytokine and chemokine profile in sera of intrinsic asthmatics and control subjects.

METHODS

Blood was taken from 10 intrinsic asthmatic female and 12 control female subjects. Expression profile of 42 different cytokines and chemokines were measured using a microarray composed of antibodies against the cytokines and chemokines. Complete blood count and C-reactive protein were measured, to assess the state of inflammation in both groups.

RESULTS

We have identified Macrophage Colony Stimulating Factor, a proinflammatory cytokine and Monocyte Chemoattractant Protein 2, a CC chemokine as having significantly higher expression levels in intrinsic asthmatic subjects compared to controls (341.71±31.28 SEM Signal intensity) versus (247.97±28.09 SEM Signal intensity), p=0.036 and (397.07±38.19 SEM Signal intensity) versus (311.33±28.76 SEM Signal intensity), p=0.036, respectively. There were no significant differences in the other cytokines and chemokines measured nor were there any differences in the inflammatory measurements between the two groups except for eosinophil counts, the hall mark of intrinsic asthma.

CONCLUSION

Macrophage Colony Stimulating Factor and Monocyte Chemoattractant Protein are elevated in sera of intrinsic asthmatics compared to normal controls. These cytokines may have a critical role in the inflammatory pathology of intrinsic asthma.

An imbalance in C/EBPs and increased mitochondrial activity in asthmatic airway smooth muscle cells: novel targets in asthma therapy?

The asthma prevalence was increasing over the past two decades worldwide. Allergic asthma, caused by inhaled allergens of different origin or by food, is mediated by inflammatory mechanisms. The action of non-allergic asthma, induced by cold air, humidity, temperature or exercise, is not well understood. Asthma affects up to 15% of the population and is treated with anti-inflammatory and muscle relaxing drugs which allow symptom control. Asthma was first defined as a malfunction of the airway smooth muscle, later as an imbalanced immune response of the lung. Recent studies placed the airway smooth muscle again into the focus. Here we summarize the molecular biological basis of the deregulated function of the human airway smooth muscle cell as a cause or important contributor to the pathology of asthma. In the asthmatic human airway smooth muscle cells, there is: (i) a deregulation of cell differentiation due to low levels of maturation-regulating transcription factors such as CCAAT/enhancer binding proteins and peroxisome proliferator-activated receptors, thereby reducing the cells threshold to proliferate and to secrete pro-inflammatory cytokines under certain conditions; (ii) a higher basal energy turnover that is due to increased number and activity of mitochondria; and (iii) a modified feedback mechanism between cells and the extracellular matrix they are embedded in. All these cellular pathologies are linked to each other and to the innate immune response of the lung, but the sequence of events is unclear and needs further investigation. However, these findings may present the basis for the development of novel curative asthma drugs.