The glutathione-S-transferase gene polymorphisms (Gstt1, Gstm1, and Gstp1) in patients with non-allergic nasal polyposis

The Effects of VEGF-A and GSTM1/GSTT1 Variants in the Susceptibility to the Chronic Rhinosinusitis with Nasal Polyposis: A Pilot Genetic Study

Nasal polyps (NPs) are usually part of chronic rhinosinusitis with nasal polyposis (CRSwNP). However, the exact etiology of CRSwNP is still unknown. In addition, the suggested etiological causes are infection, allergy, and immunological disorders, among others, such as genetic predisposition. Moreover, it is also suggested that oxygen-free radicals play a vital role in the pathogenesis of nasal polyposis, and inflammatory cells produce free radicals during phagocytosis, which is the primary source of ROS, controlled by the glutathione S-transferase (GST) system. Although, vascular endothelial growth factor (VEGF) plays an important role in angiogenesis, it is closely interwoven with the mobilization of inflammatory cells. This pilot study evaluated the association between genetic variant VEGF-A (rs28357093) and GSTM1/GSTT1 deletion polymorphism in susceptibility to CRSwNP. A case-control study was conducted with 61 individuals diagnosed with CRSwNP and 100 healthy subjects. VEGF-A (rs28357093) and GSTM1/GSTT1 deletion polymorphisms were genotyped by RFLP-PCR and SYBR Green real-time PCR, respectively. Individuals with allergic rhinitis carriers with AC genotype (rs28357093) presented a 4-fold increased risk to CRSwNP (OR = 4.20, 95% CI = 1.31 to 13.50; p = 0.015). This evidence shows that the increased vascular permeability probably causes an inflamed nasal area leading to extensive edema and polyp growth. On the other hand, no association was verified for each genetic variant by inheritance models. Interestingly, the GSTT1 present genotype showed a protective effect on CRSwNP. In conclusion, additional studies that have larger groups in different geographic localizations may be useful to verify and assess the association between genetic variants and CRSwNP.

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.

Does procalcitonin have a role in the pathogenesis of nasal polyp?

PURPOSE

The aim of this study is to investigate serum and tissue procalcitonin (PCT) levels in patients with nasal polyps.

METHODS

The study was designed to be prospectively controlled and included 26 patients chronic rhinosinusitis with nasal polyp (CRSwNP) endoscopically diagnosed and as a control group 25 chronic rhinosinusitis without nasal polyp (CRSsNP). NP specimens, nasal mucosal tissue and venous blood samples of both groups were collected and PCT levels determined by Elisa method. The results were compared statistically.

RESULTS

Serum PCT values were 1319.5 pg/mL in the NP group and 818.8 pg/mL in the control group. The difference between the groups was statistically significant (p = 0.0001). In the NP group, the average PCT value of the polyp tissue was 1521.5 pg/gr, while the mean PCT value of the control group in the nasal mucosa was 414.6 pg/gr. There was a statistically significant difference between the groups (p = 0.0001). The tissue cut-off value of PCT 750 was significant [area under curve 0.940 (0.863-1.00)]. Serum PCT 950 cut-off value was significant [area under curve 0.860 (0.748-0.972)] activity (CI: 95%).

CONCLUSIONS

This is the first study of its kind to objectively examine PCT in the polyp and serum of CRSwNP patients. PCT may serve as a diagnostic biomarker in nasal polyps.

Glutathione S-transferase gene polymorphisms and risk of nasal or colorectal polyposis

We observed inconsistent conclusions regarding the genetic role of glutathione S-transferase gene polymorphisms, including glutathione S-transferase M1 (GSTM1), glutathione S-transferase T1 (GSTT1) present/null, and glutathione S-transferase pi (GSTP1) Ile105Val polymorphisms, in the susceptibility to nasal or colorectal polyposis (NP or CP). Thus, we aimed to perform a meta-analysis to comprehensively evaluate this association by applying Stata/SE software. After the heterogeneity assumption, Mantel-Haenszel statistics were used to obtain the odds ratio (OR), 95% confidence interval (95% CI) and P-value of the association test (P_A ). We obtained a total of 235 articles by searching online databases. After screening, ten eligible case-control studies were finally enrolled in our meta-analysis. For the meta-analysis of the GSTT1 gene under present versus null, we observed a decreased risk of NP [OR = 0.65; P_A =0.018], but not CP. In addition, we did not detect any evident association between the GSTM1 present/null polymorphism and NP or CP risk. For the meta-analysis of the GSTP1 Ile105Val polymorphism, compared with controls, an increased risk of NP cases was detected under the models of Val versus Ile (OR = 1.36; P_A =0.027), Ile/Val versus Ile/Ile (OR = 1.70; P_A =0.011) and Ile/Val+Val/Val versus Ile/Ile (OR = 1.65; P_A =0.010). In conclusion, the null genotype of the GSTT1 polymorphism may be linked to an increased susceptibility to NP, whereas the Ile/Val genotype of the GSTP1 Ile105Val polymorphism may be associated with a decreased risk of NP.

What is the evidence for genetics in chronic rhinosinusitis?

PURPOSE OF REVIEW

To perform analysis of evidence in current literature on the topic of genetics and chronic rhinosinusitis (CRS), with a particular focus on recent findings in the cystic fibrosis transmembrane regulator (CFTR), genes associated with primary ciliary dyskinesia, and taste receptor T2R38. Other genes that have been found to have association with CRS are also presented and discussed.

RECENT FINDINGS

Recent studies in CFTR and CRS research have investigated possible CFTR-potentiators for treatment of refractory CRS. The T2R38 gene has been shown to be applicable in the clinical setting with a testable phenotype and may have a role in the prognosis and influencing management strategies of CRS patients. Many genes of the immune system have been studied, with genome-wide association studies and candidate-gene approaches identifying new associations that will need replication and further elucidation.

SUMMARY

CRS is a multifactorial disease, with strong evidence of a genetic component in its pathophysiology for some cases. Currently, there are over 70 genes that have been genetically associated with CRS in the past 15 years. Future investigations into genetic causes and predispositions of CRS may allow for improved prognostication and development of disease-prevention strategies as well as novel therapeutic targets.

Is there any effect of neurotrophin-3 on the pathogenesis of non-allergic nasal polyps?

BACKGROUND

Although the role of neurotrophins such as nerve growth factor and brain-derived neurotrophic factor in nasal polyps development has been studied, the contribution of neurotrophin-3 has not been evaluated yet. This study aimed to investigate the possible role of neurotrophin-3 in nasal polyps pathogenesis.

METHODS

The study group comprised 70 non-allergic nasal polyps patients and the control group consisted of 53 patients with middle turbinate concha bullosa. Specimens were taken, during surgery, from the ethmoid sinus nasal polyps in the nasal polyps group and from the lateral part of the middle turbinate concha bullosa in the control group. Tissue and serum levels of neurotrophin-3 were assessed by immunohistochemistry and enzyme-linked immunosorbent assay, respectively.

RESULTS

Nasal polyps patients had higher tissue neurotrophin-3 scores (p < 0.001). There was no statistically significant difference between groups regarding serum neurotrophin-3 levels (p = 0.417). Tissue neurotrophin-3 staining scores in the nasal polyps group had no statistically significant correlation with Lund-Mackay scores (p = 0.792).

CONCLUSION

Neurotrophin-3 may have a local effect in nasal polyps pathogenesis, without joining systemic circulation.

TNF-α and IL-1 β Cytokine Gene Polymorphism in Patients with Nasal Polyposis

Objective

Nasal Polyp (NP) is a benign mass of the paranasal sinuses that protrudes into the nasal cavity. The exact underlying pathogenesis is not known. In this study we aimed to determine the genetic susceptibility of NP formation in relation to TNF-α-308 and IL-1β-511 promoter region gene polymorphisms.

Methods

A total of 71 patients with NP with asthma (n=21) or without asthma (n=50) were taken as the study group, and 91 healthy volunteers were taken as the control group. Blood was gathered into EDTA-containing tubes, and patient DNA was extracted. The polymorphisms of the IL-β and TNF-α cytokine genes were analyzed using real time polymerase chain reaction.

Results

The GG genotype in the TNF-α-308 region and the CC genotype in the IL-1β-511 region were found to be risk factors for NP formation (OR: 9.2, p=0.007 and OR: 33.3, p=0.001, respectively). Regarding allelic frequencies, the G allele at the TNF-α-308 promoter region was a risk factor for NP formation (OR: 6.06, p<0.001).

Conclusion

TNF-α GG genotype in the -308 promoter region and the IL-1β CC genotype in the -511 region are genetic risk factors for NP formation.

Risk factors for chronic rhinosinusitis

PURPOSE OF REVIEW

To review the recent literature on risk factors for chronic rhinosinusitis (CRS) with an emphasis on genetic, comorbid diseases and environmental factors associated with CRS. Through identifying potential risk factors for CRS, we aim to glean insights into the underlying pathogenic mechanisms essential for developing effective therapeutic strategies.

RECENT FINDINGS

Recent findings demonstrate that genetics and comorbid medical conditions including airway diseases, gastroesophageal reflux disease, inflammatory and autoimmune diseases, and various demographic and environmental factors are associated with having a CRS diagnosis. Limitations of current studies include variable application of disease definitions, lack of prospective longitudinal studies and a disproportionate focus on tertiary care populations.

SUMMARY

CRS has a broad spectrum of associations ranging from genetics to comorbid diseases and environmental factors. These predisposing factors may provide valuable information for possible designing of therapeutic and preventive interventions. However, to better understand whether these associations cause CRS, further studies are needed to independently replicate findings, establish temporal relationships between exposure and disease onset, evaluate the influence of exposure dose on disease severity, and to understand the biological effects of these risk factors in the context of CRS.

Genetics of chronic rhinosinusitis: state of the field and directions forward

The cause of chronic rhinosinusitis (CRS) remains unclear. Study of the genetic susceptibility to CRS might be a valuable strategy to understand the pathogenesis of this burdensome disorder. The purpose of this review is to critically evaluate the current literature regarding the genetics of CRS in a comprehensive fashion. The most promising findings from candidate gene studies include the cystic fibrosis transmembrane conductance regulator gene (CFTR), as well as genes involved in antigen presentation, innate and adaptive immune responses, tissue remodeling, and arachidonic acid metabolism. We also review the few hypothesis-independent genetic studies of CRS (ie, linkage analysis and pooling-based genome-wide association studies). Interpretation of the current literature is limited by challenges with study design, sparse replication, few functional correlates of associated polymorphisms, and inadequate examination of linkage disequilibrium or expression quantitative trait loci for reported associations. Given the relationship of CRS to other airway disorders with well-characterized genetic components (eg, asthma), study of the genetics of CRS deserves increased attention and investment, including the organization of large, detailed, and collaborative studies to advance knowledge of the mechanisms that underlie this disorder.

Glutathione S-transferase polymorphisms, asthma susceptibility and confounding variables: a meta-analysis

Oxidative stress is one of the main risk factors for asthma development. Glutathione S-transferases play an important role in antioxidant defences and may influence asthma susceptibility. In particular, GSTM1 and GSTT1 positive/null genotypes and the GSTP1 Ile105 Val polymorphism have been analyzed in a number of genetic association studies, with conflicting outcomes. Two previous meta-analyses have attempted to clarify the associations between GST genes and asthma, but these studies have also showed contrasting results. Our aim was to perform a meta-analysis that included independent genetic association studies on GSTM1, GSTP1, and GSTT1, evaluating also the effect of potential confounding variables (i.e. ethnicity, population age, and urbanization). Systematic review and meta-analysis of the effects of GST genes on asthma were conducted. The meta-analyses were performed using a fixed or, where appropriate, random effects model. The meta-analysis of the GSTM1 (n = 35), GSTT1 (n = 31) and GSTP1 (n = 28) studies suggests that no significant associations with asthma susceptibility were observed for GSTM1 and GSTP1 gene polymorphisms, whereas a significant outcome was detected for the GSTT1 positive/null genotype (pooled OR = 1.33, 95 %CI = 1.10-1.60). However, high between-study heterogeneity was identified in all the general analyses (p heterogenetity < 0.05). The stratification analysis seems to explain the heterogeneity only in few cases. This picture is probably due to the interactive process of genetics and environment that characterizes disease pathogenesis. Further studies on interactions of GST genes with the potential oxidative stress sources and with other antioxidant genes are needed to explain the role of GST enzymes in asthma.