The Significance of Serum Nitric Oxide Levels in Behçet's Disease and Recurrent Aphthous Stomatitis

An N-nitrosation reaction-based fluorescent probe for detecting nitric oxide in living cells and inflammatory zebrafish

Nitric oxide (NO), an essential biological messenger molecule, participates in various physiological and pathological processes. The sensitive and specific detection of NO is of great significance for understanding the biological function of NO. Here, we synthesized a fluorescent probe (Rho-NO) for highly selective detection of NO both in vitro and in vivo. The high selectivity of Rho-NO is attributed to the fact that NO is easily replaced by electron donor amino group to form N-nitrosation products, causing rhodamine spiro ring open and fluorescence emit. Rho-NO showed a good linear response to NO (0-100 µM) with a low detection limit (0.06 µM). Importantly, it exhibited excellent specificity for NO detection in human serum and was also applied for imaging NO in living cells and inflammatory model of zebrafish. This work proves the potential of Rho-NO in pathological research and disease diagnosis.

Mean platelet volume as a predictor in the differentiation of Behçet's disease from recurrent aphthous stomatitis - A single centre, prospective, case-control study

INTRODUCTION

Recurrent oral ulcers (ROUs) are the most common disorder of the oral cavity in the community. The most challenging issue for the clinician to deal with in the diagnosis is to distinguish whether ROUs are associated with primarily Behçet's disease (BD). We aimed to investigate whether hemogram parameters contribute to reinforce BD suspicion in the differential diagnosis of recurrent aphthous stomatitis (RAS) and BD.

METHODS

A total of 260 participants were recruited from the dermatology department in this single-centre, prospective, case-control study. Participants meeting eligibility criteria were divided into three groups as healthy control (n = 90), RAS (n = 97) and mucocutaneous BD (n = 73). The mean platelet volume (MPV), red cell distribution width (RDW), haemoglobin, neutrophils, monocyte, lymphocytes and platelet counts were evaluated with the complete blood count. Furthermore, the neutrophil/lymphocyte ratio (NLR), monocyte/lymphocyte ratio and platelet/lymphocyte ratio were calculated. Erythrocyte sedimentation rate (ESR) and C-reactive protein were recorded. The contribution of hemogram parameters to the differentiation of BD from RAS was analysed.

RESULTS

The healthy control, RAS and BD groups were matched in terms of mean age (29.3 ± 5.8, 28.7 ± 5.6 and 29.9 ± 6.8 years; respectively) and sex distribution (women/men rate: 1.4, 1.6 and 1.7; respectively). ESR, neutrophil count and NLR were significantly higher in BD patients. (P = .032, P = .010, P = .019; respectively). MPV is significantly decreased in BD patients than in healthy control and RAS patients (P < .001). Decreased MPV (≤10 fL) and increased RDW (≥13.0%) were useful in predicting BD in patients evaluated with complaints of ROUs (OR = 9.98, 95% CI: [4.65-21.42], P < .001 and OR = 2.23, 95% CI: [1.14-3.36], P = .019, respectively).

CONCLUSIONS

Decreased MPV may be predictive for BD in selected patients with ROUs. We consider that more attention is required in terms of BD especially if MPV ≤10.0 fL.

Serum levels of total antioxidant status, nitric oxide and nitric oxide synthase in minor recurrent aphthous stomatitis patients

BACKGROUND

Recurrent aphthous stomatitis (RAS) is one of the most common inflammatory ulcerative conditions of oral cavity with uncertain etiology. Several studies have reported that oxidative stress may be associated with RAS. The aim of this study was to compare the serum levels of total antioxidant status (TAS), nitric oxide (NO) and nitric oxide synthase (NOS) in minor RAS (MiRAS) patients with healthy individuals and determine the possible association of MiRAS with the 3 physiological parameters mentioned above.

METHODS

Ninety patients with idiopathic MiRAS and 90 race-, age- and sex-matched healthy individuals were included in this study. All these subjects were allocated to 3 groups: MiRAS patients in the active stage (Group A); the same MiRAS patients in Group A in the inactive stage (Group B); healthy individuals without MiRAS (Group C). Serum levels of TAS, NO and NOS were determined by the spectrophotometric method. Independent sample t test and paired t test were performed for statistical evaluation.

RESULTS

Serum TAS level of Group A was significantly decreased than that of Group C, whereas the serum level of NO was significantly higher in Group A as compared to Group C (P < .05). The serum levels of TAS and NO in Group B were no significant differences when compared with those in Group A or Group C. No significant differences in NOS activities were also found between the 3 groups (P > .05).

CONCLUSIONS

MiRAS is associated with decreased TAS and increased NO levels, but NOS may not play an important role in the aetiopathogenesis.

Urinary Metabolomic Profiling to Identify Potential Biomarkers for the Diagnosis of Behcet's Disease by Gas Chromatography/Time-of-Flight-Mass Spectrometry

Diagnosing Behcet's disease (BD) is challenging because of the lack of a diagnostic biomarker. The purposes of this study were to investigate distinctive metabolic changes in urine samples of BD patients and to identify urinary metabolic biomarkers for diagnosis of BD using gas chromatography/time-of-flight-mass spectrometry (GC/TOF-MS). Metabolomic profiling of urine samples from 44 BD patients and 41 healthy controls (HC) were assessed using GC/TOF-MS, in conjunction with multivariate statistical analysis. A total of 110 urinary metabolites were identified. The urine metabolite profiles obtained from GC/TOF-MS analysis could distinguish BD patients from the HC group in the discovery set. The parameter values of the orthogonal partial least squared-discrimination analysis (OPLS-DA) model were R²X of 0.231, R²Y of 0.804, and Q² of 0.598. A biomarker panel composed of guanine, pyrrole-2-carboxylate, 3-hydroxypyridine, mannose, l-citrulline, galactonate, isothreonate, sedoheptuloses, hypoxanthine, and gluconic acid lactone were selected and adequately validated as putative biomarkers of BD (sensitivity 96.7%, specificity 93.3%, area under the curve 0.974). OPLS-DA showed clear discrimination of BD and HC groups by a biomarker panel of ten metabolites in the independent set (accuracy 88%). We demonstrated characteristic urinary metabolic profiles and potential urinary metabolite biomarkers that have clinical value in the diagnosis of BD using GC/TOF-MS.

Oxidases and oxygenases in regulation of neutrophil redox pathways in Behçet's disease patients

This study aimed to determine plasma and neutrophil oxidase activities that may contribute to vascular inflammation in Behçet's disease (BD) patients. Cyclooxygenase (COX), NADPH oxidase and myeloperoxidase (MPO) activity was determined in neutrophils isolated from BD patients and healthy controls. Functional assay of NADPH oxidase was significantly increased in BD patients, both at basal conditions and in response to fMLP stimulation. There was a significant increase in plasma MPO activity in the disease group as compared to controls. Total COX activity was significantly increased in BD neutrophils. The increase in total COX activity was accompanied with enhanced activity of COX-2, differentiated by using the COX-1 isoform-specific inhibitor SC-560. Neutrophil nitrate/nitrite levels showed no significant difference in BD; however, plasma nitrate/nitrite contents in BD patients were significantly greater compared to controls. In conclusion, increased plasma MPO, neutrophil NADPH and COX activities may contribute to intravascular inflammation documented in BD patients.

Endothelial nitric oxide synthase gene polymorphisms are not associated with recurrent aphthous stomatitis

OBJECTIVE

Recurrent aphthous stomatitis (RAS) is a common ulcerative disease of the oral mucosa. Recurrent oral aphthous ulceration is the most common and consistent feature of the more serious and systemic Behçet's disease (BD). Association of endothelial nitric oxide synthase (eNOS) gene polymorphisms with BD have been reported in different populations. This study aims to investigate if there is an association between these polymorphisms and RAS.

METHODS

A case-control association study using 91 Caucasoid RAS patients and 91 ethnically matched systemically healthy controls were genotyped for the -786 and 894 eNOS single nucleotide polymorphisms (SNPs) and a variable number of tandem repeat (VNTR) polymorphism. Chi-square analysis was used to compare the allele and genotype frequencies.

RESULTS

No significant difference was found in the distribution of allele and genotype frequencies of the -786 and +894 polymorphisms or the VNTR polymorphism between cases and controls.

CONCLUSION

eNOS gene polymorphisms associated with BD are not associated with RAS. This suggests that the oral ulceration common to both conditions may have a different underlying genetic aetiology. Although our data suggests that RAS does not have an association with eNOS, it is still possible that nitric oxide is involved in the disease process. This could still occur through localised and inflammation driven regulation by iNOS.