Trace elements in nasal polyps

Expression Levels of Glutathione S-Transferase and Cytochrome P450 Isoenzymes in Nasal Polyp Tissue

Nasal polyps are benign sinonasal masses composed of eosinophils and extracellular edema. Pathogenesis of the polyp formation is unclear but several studies strongly suggest a correlation with infection, inflammation and allergy conditions. Our aim is to investigate the potential link between allergy and nasal polyp in tissue level. Nasal polyp group included 60 patients whose diagnosis was confirmed with biopsy and the control group included 38 healthy patients. Tissue sample of the control group was taken from inferior turbinate mucosa under local anesthesia and nasal polyp tissue was collected from functional endoscopic sinus surgery. The glutathione S-transferase (GST) and cytochrome P450 (CYP) isoenzyme expressions of the tissue samples were investigated under light microscopy and graded by a senior pathologist. GSTP1 protein expression was significantly higher in tissue samples from nasal polyp group compared to that of control group (p < 0.05). However, CYP1A1, GSTM1 and GSTA1 isoenzymes were not different between the two groups (p > 0.05). We have found that GSTP1 isoenzyme was elevated in nasal polyp tissue compared to the control. The increase in protein expression of GSTP1 might have occured as a tissue response to the increased oxidative stress thus suggesting a role of GSTP1 in polyp formation.

Oxidative Stress and Air Pollution: Its Impact on Chronic Respiratory Diseases

Redox regulation participates in the control of various aspects of metabolism. Reactive oxygen and nitrogen species participate in many reactions under physiological conditions. When these species overcome the antioxidant defense system, a distressed status emerges, increasing biomolecular damage and leading to functional alterations. Air pollution is one of the exogenous sources of reactive oxygen and nitrogen species. Ambient airborne particulate matter (PM) is important because of its complex composition, which includes transition metals and organic compounds. Once in contact with the lungs' epithelium, PM components initiate the synthesis of inflammatory mediators, macrophage activation, modulation of gene expression, and the activation of transcription factors, which are all related to the physiopathology of chronic respiratory diseases, including cancer. Even though the pathophysiological pathways that give rise to the development of distress and biological damage are not fully understood, scientific evidence indicates that redox-dependent signaling pathways are involved. This article presents an overview of the redox interaction of air pollution inside the human body and the courses related to chronic respiratory diseases.

Evaluation of Advanced Oxidation Protein Products (AOPP) and Superoxide Dismutase (SOD) Tissue Levels in Patients with Nasal Polyps

The aim of this study is to eveluate levels of advanced oxidation protein products (AOPP) which are thought to increase in the polyp tissue and superoxide dismutase (SOD), an antioxidant enzyme, with using specthrophotometry in polyp tissue and healthy mucosa. 30 nasal polyp patients without inflammatory disease except for nasal polyposis were included in the study. The control group consisted of 18 patients who did not have allergy, asthma, inflammatory and granulomatous disease and planned surgery due to septum deviation and concha hypertrophy. AOPP and SOD tissue levels were measured by spectrophotometry in polyp tissue specimens taken from patients with nasal polyps and concha samples taken from patients in the control group. The mean AOPP tissue level of patients in the nasal polyposis group was statistically significantly higher than the control group. (p < 0.05). The mean SOD activity level was significantly lower in the nasal polyposis group than the control group. (p < 0.05) As a result of this study, high AOPP levels in polyp tissue and low SOD levels in polyp tissue compared to healthy nasal mucosa, oxidative stress plays an important role in nasal polyp development.

Epithelial physical barrier defects in chronic rhinosinusitis

INTRODUCTION

Chronic rhinosinusitis (CRS) is a common upper airway disease with a prevalence of greater than 10% of the general population. Although the pathogenesis of CRS remains poorly understood, there is growing evidence indicating that epithelial physical barrier defects play an important role in CRS pathogenesis. Areas covered: Epithelial physical barriers are maintained by various intercellular junctions, especially tight junctions (TJs). Recent studies suggest that the expression of TJ molecules and epithelial barrier function in human nasal epithelium are modulated by various internal and external factors. This review summarizes recent advances regarding the structure, function, and regulating mechanisms of the epithelial physical barrier in the context of CRS. Expert opinion: Available data indicate that epithelial physical barrier defects in CRS can result from inhaled allergens, microbial or virus infections, cytokines, hypoxia, or zinc deficiency, among other causes. Several genes/molecules, such as SPINK5, S100A7, S100A8/9, PCDH1, NDRG1, SPRR, and p63 are involved in modulating the physical barrier function in the context of CRS. The exact mechanisms and molecular pathways that lead to these barrier defects, however, require additional study. Additional work is necessary to further explore the epithelial physical barrier function in normal and pathologic sinonasal mucosa.

Mucociliary transport as a link between chronic rhinosinusitis and trace element dysbalance

Chronis rhinosinusitis is considered as a widespread public health issue with a prevalence of 10%. The disease significantly reduces quality of life and increases the risk of cardiovascular diseases as well as certain forms of cancer. Alteration of mucociliary clearance frequently observed in the patients and plays a significant role in disease pathogenesis. Certain studies have demonstrated that patients with chronic rhinosinusitis are characterized by significant reduction of essential trace elements and toxic metal overload. However, the particular mechanisms of the role of trace element dysbalance in chronic rhinosinusitis are unclear. We hypothesize that exposure to toxic trace elements (arsenic, nickel, cadmium) damages ciliary mucosal epithelium thus affecting mucociliary transport. In turn, altered mucociliary transport results in reduced removal of the inhaled metal-containing particles from nasal mucosa leading to their absorption and further aggravation of toxicity. Essential trace elements (zinc, selenium) play a significant role in regulation of mucociliary transport and immunity, thus their deficiency (either dietary or due to antagonism with toxic metals) may be associated with impaired functions and increased toxic metal toxicity. Therefore, a vicious circle involving metal accumulation and toxicity, essential element deficiency, impairment of mucociliary transport and metal particle removal, resulting in further accumulation of metals and aggravation of toxic effects is formed. The present hypothesis is supported by the findings on the impact of trace elements especially zinc and arsenic on mucociliary clearance, the role of mucociliary transport in heavy metal particles elimination from the airways, trace element dysbalance in chronic rhinosinusitis, as well as toxic and essential metal antagonism. The data from hypothesis testing and its verification may be used for development of therapeutic approach for management of chronic rhinosinusitis. Particularly, the use of essential elements (zinc, selenium) may reduce toxic metal toxicity thus destroying the vicious circle of heavy metal exposure, toxicity, alteration of mucociliary clearance, and aggravation of chronic rhinosinusitis. Essential element supplementation may be considered as a tool for management of chronic refractory rhinosinusitis. In addition, analysis of essential and toxic trace element status may provide an additional diagnostic approach to risk assessment of chronic rhinosinusitis in highly polluted environments.

Quantitative analysis of multiple elements in healthy and remodeled epithelium from human upper airway mucosa using nuclear microscopy

Elements are vital in airway mucosal physiology and pathology, but their distribution and levels in the mucosa remain unclear. This study uses the state-of-the-art nuclear microscopy facility to map and quantify multiple elements in the histology sections of nasal mucosa from patients with nasal polyps or inverted papilloma. Our results demonstrate that P and Ca are the most abundant elements in mucosa and their distinct difference between epithelial and subepithelial regions; more importantly, our results reveal decreased amounts of Cu and Zn in the remodeled epithelium as compared to the normal epithelium. These findings suggest that Cu and Zn may be beneficial targets to regulate aberrant epithelial remodeling in airway inflammation.

Influence of metals on rhinosinusal polyposis in Sardinian population (Italy)

Metals have strong toxic effects in humans and can act as immunoregulatory factors. The purpose of our study was to determine whether the concentrations of metals are associated with the clinical course of nasal polyposis (NP). We measured the concentrations of 10 metals and non-metal (Zn, Mn, Se, Fe, Cr, Ni, Pb, Al, Cd, and Cu) in 58 patients with NP, and 29 controls with a healthy nasal mucosa. We used electron microscopy to compare the ultrastructural features of the nasal mucosa between NP patients and healthy controls. Concentrations of metals in nasal polyps and healthy mucosa were determined by mass spectrometry. Transmission electron microscopic (TEM) and scanning electron microscopic (SEM) images of the nasal mucosa were obtained. The mean tissue concentrations of all 10 metals and non-metal were significantly lower in NP patients than in healthy controls (P < 0.05).TEM and SEM revealed changes in the mucosal ultrastructure in NP with progressive fibrosis, devascularisation, and inflammation. Tissue concentrations of metals were lower in NP patients than in healthy controls, and this was particularly evident in massive polyposis.

Heavy metals in normal mucosa and nasal polyp tissues from Tunisian patients

Despite growing evidence that bacteria, fungi, allergens, and superantigens play a prominent role in the pathophysiology of nasal polyps (NP), the exact cause of polyposis is still unknown. The etiology of NP is considered multifactorial. Until now, there is no information on the presence of heavy metals, such as cadmium (Cd), chromium (Cr), nickel (Ni), and arsenic (As) or of their role, in the pathogenesis of NP disease. In this study, concentrations of these four metals in tissue of NP were determined using Atomic Absorption Spectrometry. The Ni, Cr, and As levels in NP tissues were 2.1-, 3.2-, and 8.0-fold higher than those of normal mucosa (p < 0.05), respectively. A strong effect of cumulative smoking as expressed in the number of pack per year (PY), Ni, As, and Cd levels in NP tissue samples of patients ever-smokers (1-20 and >20 PY) are significantly higher than those of non-smokers (p = 0.006, 0.002, and < 0.001, respectively). The highest As concentrations among patients lived at polluted areas (1-25 and > 25 years) were observed in both nasal mucosa and NP tissues. The Ni and As in both nasal mucosa and NP tissues of patients occupationally exposed were significantly higher than non-exposed group. Cr and As levels were found to be associated with NP stage classification (p < 0.05). This is the first report to describe an association between concentrations of metals (Cr, As, and Ni) in human NP tissues and the risk of NP disease. Tissue metal levels have increased due to smoking, environmental, and occupational exposure. Therefore, heavy metal exposure may increase the risk of NP in the Tunisian population. The considerable risk in the category of highest cumulative exposure argues for an association between heavy metals exposure and nasal polyposis risk. Future investigations with larger samples should better elucidate this association.