Clinical implications of serum retinol-binding protein 4 in asthmatic children

Evaluation of common protein biomarkers involved in the pathogenesis of respiratory diseases with proteomic methods: A systematic review

AIM

Respiratory disease (RD) is one of the most common diseases characterized by lung dysfunction. Many diagnostic mechanisms have been used to identify the pathogenic agents of responsible for RD. Among these, proteomics emerges as a valuable diagnostic method for pinpointing the specific proteins involved in RD pathogenesis. Therefore, in this study, for the first time, we examined the protein markers involved in the pathogenesis of chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), asthma, bronchiolitis obliterans (BO), and chemical warfare victims exposed to mustard gas, using the proteomics method as a systematic study.

MATERIALS AND METHODS

A systematic search was performed up to September 2023 on several databases, including PubMed, Scopus, ISI Web of Science, and Cochrane. In total, selected 4246 articles were for evaluation according to the criteria. Finally, 119 studies were selected for this systematic review.

RESULTS

A total of 13,806 proteins were identified, 6471 in COPD, 1603 in Asthma, 5638 in IPF, three in BO, and 91 in mustard gas exposed victims. Alterations in the expression of these proteins were observed in the respective diseases. After evaluation, the results showed that 31 proteins were found to be shared among all five diseases.

CONCLUSION

Although these 31 proteins regulate different factors and molecular pathways in all five diseases, they ultimately lead to the regulation of inflammatory pathways. In other words, the expression of some proteins in COPD and mustard-exposed patients increases inflammatory reactions, while in IPF, they cause lung fibrosis. Asthma, causes allergic reactions due to T-cell differentiation toward Th2.

The pathophysiological role of adipokines in the development of bronchial asthma combined with obesity

The combined course of bronchial asthma (BA) and obesity is one of the urgent medical and social problems that requires a comprehensive and careful study in connection with a decrease in the quality of life of such patients, an increase in the frequency, duration of hospitalization and a high economic burden for the state as a whole. The relationship between BA and obesity is now confirmed by numerous studies, at the same time, despite the variability of the proposed mechanisms of pathogenetic effects of obesity on asthma, metabolic aspects of the relationship of these diseases need further study. Adipose tissue hormones are responsible for the energy homeostasis of the body therefore, excessive accumulation of adipose tissue is accompanied by the development of an imbalance in metabolic processes in various organs and tissues. Due to the emergence of new scientific data on the role and function of adipokines in the body, metabolic effects of adipokines are considered in the focus of their pathophysiological association with obesity and asthma. This literary review highlights the current understanding of the role of metabolic effects of the most studied adipokines (resistin, retinol-binding protein, leptin and adiponectin) in the development of obesity and BA. Gender and age-dependent features of adipokine levels in BA and obesity are described. Data on the confirmed role of adiponectin and leptin in the progression of BA combined with obesity are presented. It has been shown that the role of resistin and retinol-binding protein in the development of BA combined with obesity has not been studied. It is demonstrated that further study of metabolic activity of adipokines in BA is an actual and perspective direction of researches which will allow to develop new diagnostic and therapeutic strategies in patients with BA with obesity.

Retinol-binding protein-4 was associated with sensitization to inhalant allergens in the elderly population

BACKGROUND/AIMS

Recent evidence suggests an association between allergic sensitization and metabolic markers. However, this association has rarely been examined in the elderly. Retinol-binding protein-4 (RBP-4) is a recently identified adipokine that acts on the muscle and liver affecting insulin sensitivity. We evaluated the association between metabolic parameters and allergic sensitization in the elderly.

METHODS

We analysed the database of the Korean Longitudinal Study on Health and Aging cohort study conducted during 2005 to 2006. Atopy was identified by inhalant allergen skin prick test. Metabolic conditions were assessed using anthropometric indices and serum biomarkers such as fasting glucose, lipid, adiponectin, and RBP-4.

RESULTS

Among the 854 elderly subjects, 17.2% had atopy. Plasma RBP-4 levels were significantly higher in the atopic elderly than nonatopic elderly (p = 0.003). When RBP-4 percentiles were categorized as under three groups, the prevalence of atopy and current rhinitis increased significantly with percentiles of RBP-4 levels (p = 0.019 and p = 0.007, respectively). Log RBP-4 was associated with atopy (odds ratio [OR], 4.10; p = 0.009) and current rhinitis (OR, 2.73; p = 0.014), but not with current asthma (OR, 1.17; p = 0.824). Higher RBP-4 level in atopic elderly was also observed in current rhinitis patients. Atopy, but not current rhinitis, showed significant relationships with log RBP-4 levels in multivariate analyses adjusted for other metabolic markers including body mass index.

CONCLUSION

RBP-4 positively associated with atopy in the general elderly population irrespective of other metabolic markers.

Serum vitamin A, zinc and visual function in children with moderate to severe persistent asthma

Background: Asthma is a common childhood disorder with complex pathobiologic components that may include aspects of nutritional deficit. The contribution of vitamin deficiency, specifically vitamin A, as part of the disease complex has not been well studied, particularly among at risk children. In this study, we examined the prevalence of vitamin A as well as zinc deficiency in conjunction with visual function among an urban pediatric population sample with moderate-severe persistent asthma. Methods: A cross-sectional case-control assessment of serum vitamin A, zinc and visual function among urban children with and without asthma was undertaken. Inclusion criteria involved (1) well-controlled pediatric asthmatic patients between the ages of 8-18 with corrected vision of at least 20/25 in each eye and (2) chronic use of a combination beta agonist-steroid inhaler. Visual function was assessed by Snellen visual acuity and Peli Robson contrast sensitivity assessment. Results: Overall, 24 patients were enrolled for study with body mass index and age matched between asthmatic and control groups. Median serum vitamin A and zinc levels among control subjects was statistically higher compared to asthmatics (p = 0.0303 and p = 0.0111, respectively). Based on age-based reference levels there was no evidence of vitamin A or zinc deficiency among asthmatics or controls. Serum vitamin A and zinc were found to directly correlate with body mass index (p = 0.0074 and p = 0.0474, respectively), but not age or measures of visual function. Contrast sensitivity was however significantly reduced among asthmatic subjects (p = 0.0003). Conclusions: Children with chronic asthma demonstrate reduced levels of vitamin A and zinc that may be related to disease pathobiology however, evidence of frank zinc or vitamin A deficiency was not demonstrated. Reduced contrast sensitivity found in the asthmatic group appears unrelated to serum vitamin A and/or zinc levels.

Adipokines, asymmetrical dimethylarginine, and pulmonary function in adolescents with asthma and obesity

OBJECTIVE

This study was to investigate whether the metabolic abnormalities of adipokines and asymmetrical dimethylarginine (ADMA) associate with pulmonary function deficits in adolescents with obesity and asthma.

METHODS

This study enrolled 28 obese adolescents with asthma, 46 obese adolescents without asthma, 58 normal-weight adolescents with asthma, and 63 healthy control subjects. Serum levels of leptin, high-molecule-weight (HMW) adiponectin, retinol binding protein 4 (RBP4), asymmetrical dimethylarginine (ADMA), and pulmonary function were qualified.

RESULTS

The obese subjects had higher levels of leptin and ADMA but lower levels of HMW adiponectin than the normal-weight subjects with or without asthma. The subjects with asthma had higher levels of RBP4 than those without asthma. The obese adolescents with asthma had lowest forced expiratory lung volume in the first second (FEV₁)/forced vital capacity (FVC) ratio among the four study groups. In all the study subjects and in the subjects with asthma alone, the FEV₁/FVC ratio associated negatively with leptin, however, such association was rendered non-significant when adjusted for BMI. The pulmonary function deficits associated inversely with BMI percentile in the subjects with asthma. However, the decreased FEV₁/FVC ratio was not correlated with HMW adiponectin, RBP4 or ADMA.

CONCLUSIONS

Our present study confirmed obstructive pattern of pulmonary function characterized by the reduced FEV₁/FVC ratio in the obese adolescents with asthma. These pulmonary deficits were associated inversely with the increased BMI percentile.

Association of serum retinol binding protein 4 with adiposity and pubertal development in Korean children and adolescents

Retinol binding protein 4 (RBP4) has been postulated to provide a new link between obesity and insulin resistance. We aimed to assess the relationship between serum RBP4 and insulin resistance by investigating serum RBP4 levels in children and adolescents according to degree of obesity and pubertal stage. A total of 103 (30 lean, 39 overweight, 34 obese) were evaluated for serum RBP4, adiponectin, insulin, glucose and lipid profiles. RBP4 levels of obese and overweight groups were higher than those of lean group. RBP4 level was higher in pubertal group than in prepubertal group. RBP4 was positively correlated with age, height, weight, body mass index (BMI), abdominal circumference, systolic blood pressure, fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR), total cholesterol and triglyceride, and inversely with adiponectin. In the multiple linear regression analysis, RBP4 was found to be independently associated with pubertal stage, BMI and triglyceride but not with HOMA-IR. In conclusion, serum RBP4 level is related with degree of adiposity and pubertal development. The association of RBP4 with insulin resistance is supposed to be secondary to the relation between RBP4 and adipose tissue in children and adolescents.