Dihydropteridine reductase activity and neopterin levels in leukemias and lymphomas: is there any correlation between these two parameters?

Evaluation of Serum and Urinary Neopterin Levels as a Biomarker for Occupational Exposure to Crystalline Silica

Background:

Crystalline silica is a commonly used mineral in various industries and construction activities, and it is so important introducing potential biomarkers to identify early indicators of biological effects in its high-risk occupational exposures.

Aim:

The present study was aimed to assess the blood and urinary neopterin as an early biomarker of exposure in the workers of an insulator manufacturing plant who are exposed to crystalline silica.

Subjects and Methods:

This analytical descriptive study was done among two groups of exposed workers (n = 55) and unexposed office workers (n = 38) of an insulator manufacturing plant. Statistical software R was used to determine sample size and select the participants by random sampling among nonsmoker workers. Sampling of airborne silica in breathing zone of participants was done based on the National Institute for Occupational Safety and Health method 7601. The urinary and blood samples were collected and prepared for analysis by high-performance liquid chromatography to determine the level of urinary and serum neopterin. All of the statistical analyses were carried out using SPSS 22.

Results:

The airborne silica concentration was significantly different between two exposed and unexposed groups (P < 0.001, 0.27 [0.11] vs. 0.0028 [0.0006] mg/m³, respectively). The urinary neopterin in exposed group is significantly higher than the unexposed one (P < 0.001, 97.67 [30.24] vs. 55.52 [2.18] μmol/mol creatinine, respectively). Neopterin level of serum in exposed group is higher than the unexposed group, and there is a significant difference between them (P < 0.001, 6.90 [2.70] vs. 2.20 [1.20] nmol/l, respectively). The positive significant correlations were found between silica exposure concentration with urinary and serum neopterin (P < 0.001, r = 0.36 and 0.59, respectively).

Conclusions:

Considering the sensitively and easily measurement of neopterin in biological fluid and also the statistically significant positive relationships which were found between the airborne silica concentration and neopterin levels in the present study, the serum and urinary neopterin levels can be considered the potential biomarkers of silica exposure for doing further comprehensive studies in this area.

Immunomodulatory effects of Turkish propolis: changes in neopterin release and tryptophan degradation

In most of the diseases which are considered to benefit from propolis, cellular immune reaction is activated, neopterin levels in body fluids are increased and enhanced tryptophan degradation is observed. In this study, the immunomodulatory effects of six Turkish propolis samples were evaluated by using the in vitro model of peripheral blood mononuclear cells (PBMC). Concentrations of neopterin, tryptophan, kynurenine and pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) were determined and also the viability of the cells was checked with trypan blue and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test. In PBMC treated with mitogen phytohaemagglutinin, neopterin production and tryptophan degradation by enzyme indoleamine 2,3-dioxygenase (IDO) as well as release of cytokines was significantly enhanced and upon treatment with propolis extracts all these effects were dose-dependently suppressed. Results show an immunomodulatory effect of propolis extracts which includes down-regulation of IDO activity. IDO enzyme is considered to play an important role in the development of immunodeficiency and neuropsychiatric symptoms in patient with chronic inflammation. The suppression of tryptophan degradation by propolis extracts may therefore be related with some of its beneficial health properties in humans.

Mechanistically identified suitable biomarkers of exposure, effect, and susceptibility for silicosis and coal-worker's pneumoconiosis: a comprehensive review

Clinical detection of silicosis is currently dependent on radiological and lung function abnormalities, both late manifestations of disease. Markers of prediction and early detection of pneumoconiosis are imperative for the implementation of timely intervention strategies. Understanding the underlying mechanisms of the etiology of coal workers pneumoconiosis (CWP) and silicosis was essential in proposing numerous biomarkers that have been evaluated to assess effects following exposure to crystalline silica and/or coal mine dust. Human validation studies have substantiated some of these proposed biomarkers and argued in favor of their use as biomarkers for crystalline silica- and CWP-induced pneumoconiosis. A number of "ideal" biological markers of effect were identified, namely, Clara cell protein-16 (CC16) (serum), tumor necrosis factor-alpha (TNF-alpha) (monocyte release), interleukin-8 (IL-8) (monocyte release), reactive oxygen species (ROS) measurement by chemiluminescence (neutrophil release), 8-isoprostanes (serum), total antioxidant levels measured by total equivalent antioxidant capacity (TEAC), glutathione, glutathione peroxidase activity, glutathione S-transferase activity, and platelet-derived growth factor (PDGF) (serum). TNF-alpha polymorphism (blood cellular DNA) was identified as a biomarker of susceptibility. Further studies are planned to test the validity and feasibility of these biomarkers to detect either high exposure to crystalline silica and early silicosis or susceptibility to silicosis in gold miners in South Africa.

Serological Immunomarkers in Cutaneous T Cell Lymphoma

INTRODUCTION

As serological immunomarkers like neopterin, beta2-microglobulin, soluble IL-2 receptor (sIL-2R) and IL-6 have been described to be elevated in various malignancies, the aim of this study was to investigate whether they would be of diagnostic and prognostic value for leukemic and non-leukemic cutaneous T cell lymphoma (CTCL).

PATIENTS AND METHODS

Forty-one CTCL patients from the lymphoma clinics of the Department of Dermatology, University of Zurich, were tested for the serum levels of the above-mentioned immunomarkers at several time points, and clinical status and clinical outcome were recorded. Thirty-nine patients with CBCL and T cell inflammatory diseases served as controls.

RESULTS

The study revealed that neopterin, beta2-MG and sIL-2R are significantly elevated in Sezary syndrome, whereby sIL-2R seemed to be the most sensitive marker and is typically increased in Sezary syndrome. Moreover, there is a correlation between tumor burden index values and serum parameters. Concerning the outcome of the disease (progression versus non-progression), only neopterin showed a significant prognostic value in non-leukemic CTCL patients.

CONCLUSION

Serological immunomarkers are helpful tools in determining the tumor burden in CTCL and thus might be useful for disease monitoring during treatment. They may have prognostic value for predicting the clinical course.

Neopterin as a new biomarker for the evaluation of occupational exposure to silica

OBJECTIVES

Silica is one of the most documented workplace contaminants. Long-term occupational exposure to silica is associated with an increased risk for respiratory diseases such as silicosis, tuberculosis, chronic bronchitis, chronic obstructive pulmonary disease and lung cancer. Furthermore, a variety of immune-dysfunction-related diseases has been reported in silicotic individuals. Preliminary studies indicating enhanced levels of autoantibodies and several cytokines reflect an involvement of the immune system in the pathogenesis of silicosis and resulting complications. As an early and valuable biomarker of cellular immunity, neopterin is a low-molecular-mass compound belonging to the class of pteridines. It is produced by guanosine triphosphate via interferon-gamma, following the activation of T cells. The aim of the present study was to observe the alteration of neopterin in silica exposure, and also to show whether screening of neopterin levels may be of use for assessment of occupational exposure to silica.

METHODS

In this study, serum and urinary neopterin levels, both in silica-exposed workers ( n=22) and healthy volunteers ( n=20), were investigated by ELISA, spectrophotometry and HPLC techniques.

RESULTS

Serum neopterin levels of control and exposed groups were measured as 5.98+ or -0.44 and 7.86+ or -1.97 nmol/l, respectively ( P<0.05). Urinary neopterin levels were also increased in the exposed group: 97.60+ or -41.42 micromol/mol creatinine for controls and 165.59+/-78.20 micromol/mol creatinine for workers ( P<0.05). At the same time, the correlation between urinary neopterin levels, serum neopterin concentration and working years, smoking status, some complaints, and silica status in the working atmosphere were evaluated.

CONCLUSIONS

Our findings suggest that the following up of neopterin levels may have diagnostic value in silica-related diseases such as silicosis. Moreover, its biological monitoring should be performed in workplaces for clinical diagnosis and prognosis.

Level of neopterin, a marker of immune cell activation in gingival crevicular fluid, saliva, and urine in patients with aggressive periodontitis

BACKGROUND

Neopterin, a marker of cellular immune activation, is produced by human macrophages after induction by interferon gamma that is secreted by T lymphocytes. Neopterin concentrations in diverse body fluids have been reported to increase in parallel with bacteria in the clinical course of infections. Therefore, determination of neopterin in body fluids was thought to be useful for predicting the prognosis and diagnosis of aggressive forms of periodontal disease, in which the cell-mediated immune response plays an important role in immunopathogenesis. The aim of the present study was to observe the role of neopterin in the pathogenesis of aggressive periodontitis (AgP).

METHODS

Thirteen individuals who were systemically and periodontally healthy and 16 systemically healthy individuals diagnosed with AgP were recruited for this study. Mixed saliva and urine samples were collected from each subject. Gingival crevicular fluid (GCF) samples were obtained from 6 teeth with > or =5 mm probing depth (PD). After evaluation of GCF amount from paper strips, enzyme-linked immunosorbent assay (ELISA) was employed to determine the amount of neopterin in urine, saliva, and GCF.

RESULTS

The amount of neopterin in urine and saliva measured 235.77+/-405.31 micromol neopterin/mol creatinine and 9.85+/-7.66 nmol/l, respectively, for the AgP group and 225.45+/-100.72 micromol neopterin/mol creatinine and 5.25+/-5.76 nmol/l, respectively, for controls. The present data demonstrate that, while salivary neopterin levels were found to be significantly different between periodontitis and control subjects, there were non-significant differences in urine neopterin levels. The amount and concentration of neopterin in GCF measured was 18+/-12.75 nmol/l and 3.67+/-2.40 nmol/ml for the AgP group and 2.51+/-1.72 nmol/l and 3.88+/-4.50 nmol/ml for the control group. When total amounts of neopterin are taken into consideration, a significant difference between AgP and controls is shown; however, no significant difference in net concentration of neopterin was found between both groups.

CONCLUSIONS

This study is the first report to evaluate the involvement of neopterin in AgP and this might be considered of value in understanding periodontal disease mechanisms.

Association between homocysteine and neopterin in healthy subjects measured by a simple HPLC-fluorometric method

OBJECTIVES

Neopterin and homocysteine promote vascular smooth muscle cell proliferation through the activation of nuclear factor(kappa) B. The aim of this study was to investigate the relation between these two compounds in healthy subjects by a rapid HPLC-fluorometric method which simplifies sample pretreatment for the measurement of neopterin in serum.

DESIGN AND METHODS

In 40 healthy subjects (45.9 +/- 2.1 yr, mean +/- SEM, 10 males, 30 females) serum neopterin concentrations were measured by HPLC-fluorometry and enzyme-linked immunusorbant assay-ELISA and the results were compared. Urinary neopterin and plasma total homocysteine concentrations were assayed by HPLC-fluorometry.

RESULTS

Serum neopterin concentrations measured by HPLC and ELISA were 7.5 +/- 0.4 and 7.4 +/- 0.3 nmol/L, respectively, r = 0.92, p < 0.01. Urinary neopterin level was 163.9 +/- 11.0 nmol/mmol creatinine and plasma total homocysteine 7.6 +/- 0.4 micromol/L. A significant positive correlation was observed between serum neopterin and plasma total homocysteine (r = 0.59, p < 0.01).

CONCLUSIONS

A simple and rapid sample pretreatment for the measurement of neopterin in serum has been introduced. The significant positive correlation between neopterin and homocysteine implies that, interference with leukocyte function might be a new possible mechanism for the deleterious effects of homocysteine on vascular function.