A pilot study on neopterin levels and tryptophan degradation in zinc-exposed galvanization workers

Determination of neopterin in urine of industrial workers by HPLC

This study aimed to determine neopterin levels in the urine of industrial workers by the high-performance liquid chromatography method. Intra- and inter-day precision values for neopterin in urine were less than 3.14, and accuracy (relative error) was better than 3.00%. The limits of detection and quantification of neopterin were 0.3 and 1.0 ng/mL, respectively. Also, the developed method was applied to real samples to determine the neopterin levels in the urines of industrial workers, who have been exposed to various chemicals such as formaldehyde, heavy metals and thinners. Urine neopterin levels of industrial workers including auto painters, bodywork and furniture workers were statistically compared with healthy volunteers. The highest and lowest values of urinary neopterin for industrial workers were obtained 908.96 and 119.86 μmol/mol, respectively. Our investigation demonstrates that there is a meaningful difference in urinary neopterin levels between the workers and the control groups (P<0.05). Workers in the auto paint, body and furniture business may have been exposed to a toxic environmental exposure in their occupation. As a result, an increase in the concentration of neopterin in the urine may be important in the diagnosis and treatment of various diseases.

Mercury exposure, neopterin profile, and tryptophan degradation in dental technicians

Amalgam has been widely used as a restorative dental material for over 150 years. Most standard dental amalgam formulations contain approximately 50% elemental mercury in a mixture of copper, tin, silver, and zinc. Mercury is a highly volatile metal, which can easily vaporize to a colorless and odorless gas. It has been demonstrated that mercury is released from dental amalgam, which is increased by chewing, eating, brushing, and drinking hot liquids. Besides this, amalgam is the main occupational exposure source of mercury for dental workers. It is known that mercury exposure causes immune modulation in humans. In this study, it was aimed to evaluate the changes in neopterin levels and tryptophan (Trp) degradation in dental technicians. It was observed that low levels of occupational mercury exposure resulted in decreased neopterin, kynurenine (Kyn), and Kyn/Trp levels. Moreover, mercury and neopterin levels had a significant positive correlation in workers. The lower neopterin levels and Kyn/Trp in dental technicians compared to an unexposed group indicates a possible immune suppression with low level of occupational mercury exposure during amalgam preparation. The relationship between urinary mercury levels as an indicator of occupational mercury exposure and neopterin reminded an effect on T-cell-mediated immune response.

Comparison between plasma neopterin and the urine neopterin:creatinine ratio as inflammatory biomarkers

Background

Neopterin, a product of cell-mediated immunity, is a non-specific biomarker of inflammation. Plasma/serum is generally the body fluid of choice for neopterin assessment, but urine is often used as it does away with venepuncture. Analysis of urine neopterin is based on collection of a single urine sample and expressed as µmol neopterin/mol creatinine.

Objectives

To examine published correlations between plasma neopterin levels and urine neopterin:creatinine ratios and to determine whether they are in diagnostic agreement.

Methods

Literature search was performed by databases and by hand. Databases included Academic Search Complete; Africa-Wide Information; AHFS Consumer Medication Information; eBook Collection (EBSCOhost); Family & Society Studies Worldwide; MasterFILE Premier; MEDLINE; TOC Premier.

Results

Positive correlations of varying statistical significance generally exist between plasma neopterin and urine neopterin: creatinine ratios. With a decline in renal clearance, plasma neopterin over-estimates inflammatory activity. With immune-complex renal disease, urine neopterin:creatinine ratios over-estimate systemic inflammation. The two biomarkers can differ in diagnostic validity.

Conclusion

Correlations between plasma neopterin and urine neopterin:creatinine ratios suggest both as suitable biomarkers. However, since correlations reflect equality of means and not individual values, significant correlations, do not necessarily imply diagnostic agreement. Therefore, plasma and urine cannot summarily be assumed interchangeable for diagnostic/prognostic purposes.

Possible changes of New-Generation inflammation markers with occupational lead exposure

OBJECTIVES

Occupational lead (Pb) exposure is still an important health problem in the world. Long-term Pb exposure causes several adverse effects. The aim of this study was to investigate the changes of inflammation markers with chronic Pb exposure by analyzing neopterin levels and kynurenine (Kyn) to tryptophan (Trp) ratio that reflects indolamine 2,3-dioxygenase activity and to compare with healthy volunteers' parameters.

METHODS

Blood lead levels (BLLs) were analyzed by atomic absorption spectrometry. Urinary neopterin and serum Kyn and Trp levels were analyzed by high-performance liquid chromatography.

RESULTS

According to our results, mean BLL of the 29 workers was 20.4±9.6 μg/dl. Urinary neopterin levels, serum Kyn levels, and Kyn/Trp of Pb workers (188±52 μmol/mol creatinine, 2.70±0.66 μM, and 43.19±10.38 μmol/mmol, respectively) were significantly higher than controls (144±35 μmol/mol creatinine, 2.08±0.34 μM, and 32.24±7.69 μmol/mmol, respectively). Pb-exposed workers were divided into further three groups according to their BLLs: as 10-19 μg/dl (n=18), 20-29 μg/dl (n=8), and 30-49 μg/dl (n=3). Neopterin levels of the workers with BLL of 30-49 μg/dl were significantly higher than those of BLL with 10-29 μg/dl, while Trp levels decreased. Kyn/Trp of workers with BLL of 30-49 μg/dl were elevated significantly compared with the workers with BLL<30 μg/dl. In addition to neopterin, Kyn and Kyn/Trp levels were positively influenced by Pb exposure.

CONCLUSIONS

Increased level of inflammation markers confirms the adverse effects of Pb even low BLLs, and we suggest that monitoring BLLs with inflammation markers could help to prevent serious occupational health problems.

TiO(2) nanoparticles and bulk material stimulate human peripheral blood mononuclear cells

•

Effects on immunobiochemical pathways of TiO₂ materials were investigated in vitro.

•

TiO₂ bulk and nanomaterial stimulated neopterin production in human PBMC.

•

There was no stimulatory influence of particles on tryptophan breakdown.

•

At high particles concentrations, tryptophan breakdown was suppressed.

•

Results suggest that the total effect of particles is even stronger pro-inflammatory.

Nanomaterials are increasingly produced and used throughout recent years. Consequently the probability of exposure to nanoparticles has risen. Because of their small 1–100 nm size, the physicochemical properties of nanomaterials may differ from standard bulk materials and may pose a threat to human health. Only little is known about the effects of nanoparticles on the human immune system. In this study, we investigated the effects of TiO₂ nanoparticles and bulk material in the in vitro model of human peripheral blood mononuclear cells (PBMC) and cytokine-induced neopterin formation and tryptophan breakdown was monitored. Both biochemical processes are closely related to the course of diseases like infections, atherogenesis and neurodegeneration. OCTi60 (25 nm diameter) TiO₂ nanoparticles and bulk material increased neopterin production in unstimulated PBMC and stimulated cells significantly, the effects were stronger for OCTi60 compared to bulk material, while P25 TiO₂ (25 nm diameter) nanoparticles had only little influence. No effect of TiO₂ nanoparticles on tryptophan breakdown was detected in unstimulated cells, whereas in stimulated cells, IDO activity and IFN-γ production were suppressed but only at the highest concentrations tested. Because neopterin was stimulated and tryptophan breakdown was suppressed in parallel, data suggests that the total effect of particles would be strongly pro-inflammatory.

Endocrine and immunological parameters in individuals involved in Prestige spill cleanup tasks seven years after the exposure

In November 2002 the oil tanker Prestige spilled 63,000tonnes of heavy oil off the northwest coast of Spain, impacting more than 1000km of coastline. A general concern led to a huge mobilization of human and technical resources, and more than 300,000 people participated in cleanup activities, which lasted up to 10months. Some endocrine and immunological alterations were reported in Prestige oil exposed subjects for several months. Therefore, the objective of this study was to evaluate if these alterations are still present seven years after the exposure. Fifty-four individuals exposed for at least 2months were compared to 50 matched referents. Prolactin and cortisol plasma concentrations, percentages of lymphocyte subsets (CD3(+), CD4(+), CD8(+), CD19(+), and CD56(+)16(+)), plasma levels of circulating cytokines (interleukin (IL) 2, IL4, IL6, IL10, tumour necrosis factor α, and interferon γ), and serum concentrations of neopterin, tryptophan and kynurenine were determined in peripheral blood samples. Results showed significant differences in exposed individuals vs. referents only in cortisol (increase), kynurenine and %CD16(+)56(+) lymphocytes (both decrease). Time of exposure to the oil or using protective clothes did not influence the results, but effect of using protective mask was observed on neopterin, %CD8(+), CD4(+)/CD8(+) ratio and IL4. Surveillance of the exposed individuals for early detection of possible health problems related to the endocrine or immunological systems is recommended.