Construction of a Zn(II)-Eu(III) Nanoring with Temperature-Dependent Luminescence for the Qualitative and Quantitative Detection of Neopterin as an Inflammatory Marker

A nine-metal Zn(II)-Eu(III) nanoring 1 with a diameter of about 2.3 nm was constructed by the use of a long-chain Schiff base ligand. It shows a luminescence response to neopterin (Neo) through the enhancement of lanthanide emission with high selectivity and sensitivity, which can be used to quantitatively analyze the concentrations of Neo in fetal calf serum and urine. The luminescence sensing of 1 to Neo is temperature-dependent, and it displays more obvious response behavior at lower temperatures. Filter paper strips bearing 1 can be used to qualitatively detect Neo by the color change from chartreuse to red under a UV lamp. The limit of detection is as low as 3.77 × 10-2 nM.

Immune Activation and Anemia Are Associated with Decreased Quality of Life in Patients with Solid Tumors

Anemia often coincides with depression and impaired quality of life (QoL) in cancer patients. Sustained immune activation can lead to the development of anemia. Furthermore, it also may go along with changes in tryptophan and phenylalanine metabolism. The aim of our pilot study was to study the relationship between anemia, immune-mediated changes in amino acid metabolism, and the QoL and mood of cancer patients. Questionnaires to measure QoL and depression were completed by 152 patients with solid tumors. Hemoglobin, parameters of immune activation as well as tryptophan and phenylalanine metabolism were determined in the patients’ sera. Anemic patients (51.7%) presented with higher inflammatory markers, and a higher tryptophan breakdown with lower tryptophan concentrations. They reported an impaired QoL and had higher depression scores. Patients with an impaired QoL (65.8%) also suffered from more fatigue and impaired physical, emotional, and social functioning. They, furthermore, presented with higher concentrations of inflammatory markers (C-reactive protein (CRP) and neopterin) as well as higher tryptophan degradation (in men) and higher phenylalanine concentrations (in women). Sixty-one patients (40.1%) had (mostly mild) depression. In these patients, a higher degree of Th1 immune activation was found. The results of our study suggest that cancer-related anemia goes along with an impaired QoL, which is also associated with immune-mediated disturbances of tryptophan and phenylalanine metabolism.

Urinary 1H-NMR Metabolic Signature in Subjects Undergoing Colonoscopy for Colon Cancer Diagnosis

Metabolomics represents a promising non-invasive approach that can be applied to identify biochemical changes in colorectal cancer patients (CRC) and is potentially useful for diagnosis and follow-up. Despite the literature regarding metabolomics CRC-specific profiles, discrimination between metabolic changes specifically related to CRC and intra-individual variability is still a problem to be solved. This was a preliminary case-control study, in which 1H-NMR spectroscopy combined with multivariate statistical analysis was used to profile urine metabolites in subjects undergoing colonoscopy for colon cancer diagnosis. To reduce intra-individual variability, metabolic profiles were evaluated in participants’ urine samples, collected just before the colonoscopy and after a short-term dietary regimen required for the endoscopy procedure. Data obtained highlighted different urinary metabolic profiles between CRC and unaffected subjects (C). The metabolites altered in the CRC urine (acetoacetate, creatine, creatinine, histamine, phenylacetylglycine, and tryptophan) significantly correlated with colon cancer and discriminated with accuracy CRC patients from C patients (receiver operator characteristic (ROC) curve with an area under the curve (AUC) of 0.875; 95% CI: 0.667–1). These results confirm that urinary metabolomic analysis can be a valid tool to improve CRC diagnosis, prognosis, and response to therapy, representing a noninvasive approach that could precede more invasive tests.

Identification and age-dependence of pteridines in bed bugs (Cimex lectularius) and bat bugs (C. pipistrelli) using liquid chromatography-tandem mass spectrometry

Determining the age of free-living insects, particularly of blood-sucking species, is important for human health because such knowledge critically influences the estimates of biting frequency and vectoring ability. Genetic age determination is currently not available. Pteridines gradually accumulate in the eyes of insects and their concentrations is the prevailing method. Despite of their stability, published extractions differ considerably, including for standards, for mixtures of pteridines and even for light conditions. This methodological inconsistency among studies is likely to influence age estimates severely and to hamper their comparability. Therefore we reviewed methodological steps across 106 studies to identify methodological denominators and results across studies. Second, we experimentally test how different pteridines vary in their age calibration curves in, common bed (Cimex lectularius) and bat bugs (C. pipistrelli). Here we show that the accumulation of particular pteridines varied between a) different populations and b) rearing temperatures but not c) with the impact of light conditions during extraction or d) the type of blood consumed by the bugs. To optimize the extraction of pteridines and measuring concentrations, we recommend the simultaneous measurement of more than one standard and subsequently to select those that show consistent changes over time to differentiate among age cohorts.

Chitotriosidase, a marker of innate immunity, is elevated in patients with primary breast cancer

BACKGROUND

Cancer progression has been associated with altered immune cell function and activation. Neopterin, which is secreted by interferon-γ stimulated macrophages, exhibits an association with multiple cancer types and metastatic disease. Chitotriosidase, which is secreted by chronically activated macrophages and granulocyte-macrophage colony-stimulating factor stimulated neutrophils has not been studied in the setting of cancer.

OBJECTIVE

The goal of this discovery study was to screen chitotriosidase for diagnostic capacity in detecting cancer and compare its operating characteristics with those of neopterin.

METHODS

Serum from subjects with breast (n= 66) or prostate (n= 70) cancer, and from 204 subjects free of malignant disease were studied. Chitotriosidase was measured by enzyme activity assay, while neopterin was measured by a competitive enzyme immunoassay. Statistical analyses included group comparisons by Mann Whitney U test, diagnostic capacity by receiver operating characteristics (ROC) curve analysis and biomarker associations with physiologic and clinical measures by Spearman correlation.

RESULTS

Chitotriosidase activity was significantly higher in both cancer types compared with gender matched controls, though only in breast cancer was the diagnostic capacity significant (area under the ROC curve of 0.97 ± 0.01). In contrast, neopterin was significantly elevated in prostate cancer and exhibited discriminatory capacity (area under the ROC curve of 0.76 ± 0.05). Age, BMI, % body fat and metastasis were variables that correlated with neopterin, but not chitotriosidase levels.

CONCLUSIONS

The operating characteristics of serum chitotriosidase were different from neopterin and further analysis of chitotriosidase as a biomarker for breast cancer is warranted.

Immune System Modulation in Patients with Malignant and Benign Breast Disorders: Tryptophan Degradation and Serum Neopterin

Tryptophan degradation metabolites are known to suppress T-cell function, which is a mechanism of resistance of tumor cells against immune surveillance. The aim of this study was to evaluate tryptophan degradation along with serum neopterin levels in benign and malignant breast disease. Serum tryptophan and kynurenine levels and neopterin concentrations of 30 patients with malignant and 27 patients with benign breast disease were determined by HPLC and ELISA, respectively. The slight increase in tryptophan degradation in a subgroup of cancer patients with higher grade tumors was not statistically significant, but the increased degradation was correlated with higher neopterin concentrations. Neopterin levels in patients with malignant breast disease were significantly higher than in the benign group (p<0.05). Tryptophan degradation positively correlates with the aggressiveness of the tumor because it changes with tumor grade rather than disease stage.

Subjective Positive and Negative Sleep Variables Differentially Affect Cellular Immune Activity in a Breast Cancer Survivor: A Time-series Analysis Approach

This study on a breast cancer survivor suffering from cancer-related fatigue (CaRF) and depression investigated the bidirectional relationship between cellular immune activity and subjective sleep. The 49-year-old patient (breast cancer diagnosis 5 years before the study, currently in remission) collected her full urine output for 28 days in 12-h intervals (8:00 p.m. to 8:00 a.m. and 8:00 a.m. to 8:00 p.m.). These urine samples were used to determine urinary neopterin (cellular immune activation marker) and creatinine concentrations via high-pressure liquid chromatography (HPLC). Each morning, the patient answered questions on five sleep variables: sleep quality (SQ), sleep recreational value (SRV), total sleep time (TST), total wake time (TWT), and awakenings during sleep period (ADS). For the purpose of this study, the time series of the nighttime urinary neopterin levels and the five sleep variables were determined. Using centered moving average (CMA) smoothing and cross-correlational analysis, this study showed that increases in the positive sleep variables SQ and SRV were followed by urinary neopterin concentration decreases after 96–120 h (SQ, lag 4: r = −0.411; p = 0.044; SRV: lag 4: r = −0.472; p = 0.021) and 120–144 h (SRV, lag 5: r = −0.464; p = 0.026). Increases in the negative sleep variable TWT, by contrast, were followed by increases in urinary neopterin concentrations 72–96 h later (lag 3: r = 0.522; p = 0.009). No systematic effects in the other direction, i.e., from urinary neopterin levels to sleep, were observed in this study. Although preliminary, the findings of this study highlight the benefit of carefully investigating temporal delays and directions of effects when studying the dynamic relationship between sleep and immune variables in the natural context of everyday life.

Concentrations of neopterin, kynurenine and tryptophan in wound secretions of patients with breast cancer and malignant melanoma: a pilot study

The aim of the present pilot study was to investigate the concentrations of neopterin, kynurenine and tryptophan in wound secretion in patients undergoing surgery for breast cancer or malignant melanoma. Twenty-two patients, 16 females and 6 males, undergoing surgery for breast cancer (n=15) or malignant melanoma (n=7) were evaluated. Neopterin, kynurenine and tryptophan were determined using a high-performance liquid chromatography method. When the concentrations in wound secretions from the primary breast tumor and the axilla were compared, the neopterin/tryptophan ratio was significantly higher in the tumor wound secretions (0.92±0.41 vs. 0.61±0.14 mmol/mol; p=0.049), but no significant differences were observed in neopterin (49.2±28.6 vs. 31.5±11.1 nmol/L), tryptophan (52.9±13.0 vs. 51.2±13.3 μmol/L) and kynurenine concentrations (5.97±7.49 vs. 5.34±6.25 μmol/L) and kynurenine/tryptophan ratio (108.1±107.7 vs. 103.5±106.7 mmol/mol). No marked differences were noted in neopterin, tryptophan and kynurenine concentrations and kynurenine/tryptophan and neopterin/tryptophan ratios in sequential samples from the axilla of breast cancer patients obtained on days 1 and 2. In conclusion, present data demonstrate that the measurement of neopterin, kynurenine and tryptophan can be used to monitor local immune response after cancer surgery.

Neoadjuvant combination therapy with trastuzumab in a breast cancer patient with synchronous rectal carcinoma: a case report and biomarker study

We report a patient who presented with synchronous second primary human epidermal growth factor receptor (HER)-2-positive breast cancer and rectal cancer that both required simultaneous neoadjuvant therapy. A modified regimen combining anti-HER-2 monoclonal antibody trastuzumab with chemotherapy and external beam radiation was selected. An organ-preserving surgical procedure was possible both in the breast and the rectum. Citrulline decreased rapidly after the start of the treatment, and then gradually returned to pre-treatment levels after the completion of chemoradiation. Urinary neopterin concentrations exhibited a fluctuating course. Both serum neopterin and C-reactive protein concentrations were more or less stable during the initial administration of trastuzumab, paclitaxel and carboplatin and then increased steeply during chemoradiation and subsequently declined to pre-treatment levels during the weekly trastuzumab administration. Changes were observed in the serum retinol concentrations. A decline in lymphocyte counts was accompanied by marked changes in peripheral blood cell count-derived ratios. The present case report demonstrates a successful combination of two neoadjuvant regimens in a patient with two synchronous different second primary tumors. Data from this case also illustrate the use of biomarkers for monitoring of intensive therapeutic regimens in medical and radiation oncology.

Comparison of performance of composite biomarkers of inflammatory response in determining the prognosis of breast cancer patients

In the present study, we determined complex indices of inflammatory activity and compared the performance of these indices as prognostic biomarkers in a cohort of breast cancer patients. All proposed composite biomarkers could be evaluated in 418 out of 474 patients in the cohort with complete data on peripheral blood cell count, urinary neopterin, albumin and C-reactive protein. Neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, platelet-to-lymphocyte ratio, systemic inflammatory index, Glasgow prognostic index, modified Glasgow prognostic index, prognostic nutritional index and C-reactive protein/albumin ratio were calculated and further complex indices were proposed. Although a number of the investigated indices were significantly associated with survival in the univariate analysis, only age and stage, but none of the laboratory biomarkers or composite biomarkers, were significant predictors of survival in the whole group in the multivariate analysis. In patients evaluated before the start of the treatment, age, stage and urinary neopterin were significant predictors of survival. These results underscore the importance of neopterin as a prognostic biomarker in breast cancer.

Serum neopterin concentrations and tryptophan degradation pattern in patients with late stage larynx carcinoma

As the disease-free 5-year-survival of late stage laryngeal carcinoma patients is extremely low, indoleamine-2,3-dioxygenase-1 (IDO)-induced tryptophan degradation may represent an immune escape mechanism which plays an important role in cancer spreading in advanced stage laryngeal cancers. We examined whether the late stage laryngeal cancer enhances tumor immune evasion by the expression of systemic IDO activities and chronic cellular immune activation. Twenty-two of 42 male laryngeal cancer patients were classified as late stage cancer according to American Joint Committee on Cancer (AJCC) criteria. Their serum neopterin, tryptophan and kynurenine concentrations were compared with 30 cancer-free individuals. IDO activity was approved by correlation between serum neopterin and kynurenine/tryptophan. Late stage cancer patients preoperatively showed a significantly higher IDO activity compared to controls and early stage cancer cases. Six months after tumor removal, late stage cancer patients although having higher serum neopterin concentration compared to early stage patients or controls, they showed a significant decrease in IDO activity and tryptophan consumption. Increased systemic IDO activity may provoke the escape of tumor cells from the immune surveillance of the host. High IDO activity is due to the presence of tumor mass. Persistence of high serum neopterin levels despite tumor removal may indicate poor prognosis.

Heritability of plasma neopterin levels in the Old Order Amish

BACKGROUND

We examined the heritability of neopterin, a biomarker for cell-mediated immunity and oxidative stress, and potentially for psychiatric disorders, in the Old Order Amish.

METHODS

Plasma neopterin levels were determined in 2015 Old Order Amish adults. Quantitative genetic procedures were used to estimate heritability of neopterin.

RESULTS

Heritability of log-neopterin was estimated at 0.07 after adjusting for age, gender, and household (p=0.03). The shared household effect was 0.06 (p<0.02).

CONCLUSIONS

We found a low heritability of neopterin and small household effect, suggesting that non-household environmental factors are more important determinants of variance of neopterin levels in the Amish.

Seasonality of blood neopterin levels in the Old Order Amish

Seasonal changes in non-human animals and seasonal affective disorder (SAD) in humans are associated with immune activation in winter relative to summer. We intended to measure seasonal variation in neopterin, a marker of cellular immunity, and its interactions with gender and seasonality of mood. We studied 320 Amish from Lancaster, PA, USA (men = 128; 40%) with an average age [Standard deviation (SD)] of 56.7 (13.9) years. Blood neopterin level was measured with enzyme-linked immunosorbent assay (ELISA). Seasonality was measured with Seasonal Pattern Assessment Questionnaire (SPAQ). Statistical analysis included analysis of covariance (ANCOVAs) and multivariate linear regression. We also investigated interactions of seasonal differences in neopterin with gender, seasonality scores and estimation of SAD diagnosis. We found a significantly higher neopterin level in winter than in summer (p = 0.006). There were no significant gender or seasonality interactions. Our study confirmed the hypothesized higher neopterin level in winter. A cross sectional design was our major limitation. If this finding will be replicated by longitudinal studies in multiple groups, neopterin could be used to monitor immune status across seasons in demographically diverse samples, even if heterogeneous in gender distribution, and degree of seasonality of mood.

Peripheral blood leukocyte populations and urinary neopterin during chemotherapy in patients with breast cancer

The aim of the present study was to investigate serial changes in urinary neopterin and the populations of peripheral blood lymphocytes in breast cancer patients treated with primary chemotherapy. Thirty patients with breast cancer, including 20 patients undergoing primary chemotherapy treated with the combination of doxorubicin and cyclophosphamide with sequential administration of paclitaxel-based therapy (cohort A), and 10 patients presenting for first-line therapy of metastatic disease and treated with the combination of bevacizumab, taxane and carboplatin (cohort M) were studied. Healthy female blood donors served as control group. Significant differences were observed in baseline relative and absolute counts of peripheral blood lymphocyte subpopulations between both patient cohorts and controls. Significant changes of peripheral blood lymphocyte subpopulations were also observed during the course of chemotherapy. However, no significant changes of urinary neopterin concentrations and no correlation between urinary neopterin and peripheral blood lymphocyte counts were observed. In conclusion, present data demonstrate the presence of significant differences in peripheral blood leukocyte phenotype in breast cancer patients even before the start of primary chemotherapy. Significant changes were observed during the course of chemotherapy.

Highly efficient SERS-based detection of cerebrospinal fluid neopterin as a diagnostic marker of bacterial infection

A highly efficient recognition unit based on surface-enhanced Raman spectroscopy (SERS) was developed as a promising, fast, and sensitive tool for detection of meningococcal meningitis, which is an extremely serious and often fatal disease of the nervous system (an inflammation of the lining around the brain and spinal cord). The results of this study confirmed that there were specific differences in SERS spectra between cerebrospinal fluid (CSF) samples infected by Neisseria meningitidis and the normal CSF, suggesting a potential role for neopterin in meningococcal meningitis detection and screening applications. To estimate the best performance of neopterin as a marker of bacterial infection, principal component analysis (PCA) was performed in a selected region (640–720 cm⁻¹) where the most prominent SERS peak at 695 cm⁻¹ arising from neopterin was observed. The calculated specificity of 95 % and sensitivity of 98 % clearly indicate the effective diagnostic efficiency for differentiation between infected and control samples. Additionally, the limit of detection (LOD) of neopterin in CSF clinical samples was estimated. The level of neopterin was significantly higher in CSF samples infected by N. meningitidis (48 nmol/L), compared to the normal (control) group (4.3 nmol/L). Additionally, this work presents a new type of SERS-active nanostructure, based on polymer mats, that allows simultaneous filtration, immobilization, and enhancement of the Raman signal, enabling detection of spectra from single bacterial cells of N. meningitidis present in CSF samples. This provides a new possibility for fast and easy detection of bacteria in CSF and other clinical body fluids on a time scale of seconds. This method of detection produces consistent results faster and cheaper than traditional laboratory techniques, demonstrates the powerful potential of SERS for detection of disease, and shows the viability of future development in healthcare applications.

Levels in neurotransmitter precursor amino acids correlate with mental health in patients with breast cancer

Breast cancer is the most common cancer among females. Approximately 30% of cancer patients develop depression or depressive adaptation disorder within 5 years post diagnosis. Low grade inflammation and subsequent changes in neurotransmitter levels could be the pathophysiological link. In the current study we investigated the association of neurotransmitter precursor amino acids with a diagnosis of depression or state anxiety in 154 subjects suffering from breast cancer (BCA(+)), depression (DPR(+)), both or neither. Sociodemographic parameters, severity of depressive symptoms, and state anxiety (ANX) were recorded. Neopterin, kynurenine/tryptophan and phenylalanine/tyrosine were analysed by HPLC or ELISA. Significantly higher serum neopterin values were found in DPR(+) patients (p = 0.034) and in ANX(+) subjects (p = 0.008), as a marker of Th1-related inflammation. The phenylalanine/tyrosine ratio (index of the catecholamine pathway) was associated with the factors "breast cancer" and "depression" and their interaction (all p < 0.001); it was highest in the DPR(+)BCA(+) group. The kynurenine/tryptophan ratio (index of the serotonin pathway) was significantly associated with the factors "breast cancer" and "state anxiety" and their interaction (p < 0.001, p = 0.026, p = 0.02, respectively); it was highest in the ANX(+)BCA(+) group. In BCA(+) patients kynurenine/tryptophan ratios correlated with severity of state anxiety (r = 0.226, p = 0.048, uncorrected) and phenylalanine/tyrosine ratios with severity of depressive symptoms (r = 0.376, p < 0.05, corrected). In conclusion, levels of neurotransmitter precursor amino acids correlate with mental health, an effect which was much more pronounced in BCA(+) patients than in BCA(-) subjects. Aside from identifying underlying pathophysiological mechanisms, these results could be the basis for future treatment studies: in BCA(+) patients with depression the use of serotonin-noradrenaline reuptake inhibitors might be recommended while in those with predominant anxiety selective serotonin reuptake inhibitors might be the treatment of choice.

Correlations of neutrophil-to-lymphocyte, lymphocyte-to-monocyte and platelet-to-lymphocyte ratios with biomarkers of atherosclerosis risk and inflammatory response in patients with a history of breast cancer

The aim of the present study was to evaluate the correlations of peripheral blood cell count (PBC)-derived ratios with neopterin concentration and biomarkers of atherosclerosis risk in patients with history of breast cancer. Neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR) and platelet-to-lymphocyte ratio (PLR) were calculated in three cohorts of patients with a history of breast cancer and in controls. Significant differences were observed between PBC-derived ratios obtained from automated and manual counts. NLR and PLR were significantly higher and LMR was significantly lower in patients. NLR and PLR correlated positively with each other and negatively with LMR. NLR exhibited a significant correlation with age, glucose and C-reactive protein (CRP) concentrations, whereas LMR correlated negatively with CRP. With the exception of a correlation between LMR and urinary or serum neopterin concentrations in controls, no other correlation between neopterin concentrations and PBC-derived ratios was observed. NLR ≥3 was a significant predictor of poor survival, but neither urinary neopterin ≥205 μmol/mol creatinine, NLR ≥150 nor LMR ≥4.25 was significantly associated with survival. In conclusion, no consistent correlation was observed between urinary and serum neopterin concentrations and any of the PBC-derived ratios. In a cohort of breast cancer patients, a higher NLR predicted poor survival.

ZnO oxide films for ultrasensitive, rapid, and label-free detection of neopterin by surface-enhanced Raman spectroscopy

Efficient and low-cost surface-enhanced Raman scattering (SERS) substrates based on Au coated zinc oxide layers for the detection of neopterin were prepared.

Interferon-γ-induced inflammatory markers and the risk of cancer: the Hordaland Health Study

BACKGROUND

It has been reported that interferon-γ (IFN-γ)-induced inflammatory markers, such as circulating neopterin and kynurenine-to-tryptophan ratio (KTR), are increased in patients with cancer and are also a predictor of poor prognosis. However, whether baseline levels of these makers are associated with subsequent cancer risk in the general population remains unknown.

METHODS

We conducted a prospective analysis of the Hordaland Health Study in 6594 adults without known cancer at baseline who were enrolled between April 1998 and June 1999. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using multivariate Cox proportional hazards regression models adjusted for sex, age, body mass index, smoking status, and renal function.

RESULTS

A total of 971 incident cancer cases (507 men and 464 women) were identified over a median follow-up time of 12 years. Baseline plasma neopterin, KTR and C-reactive protein (CRP) were significantly associated with an increased risk of overall cancer in models adjusted for covariates (P for trend across quartiles = .006 for neopterin, .022 for KTR, and .005 for CRP). The multivariate-adjusted HR (95% CI) per SD increment in similar models were 1.09 (1.03-1.16) for neopterin, 1.07 (1.01-1.14) for KTR, and 1.04 (0.98-1.10) for CRP. The associations between the inflammatory markers and risk of major specific cancer types were also provided.

CONCLUSIONS

Our findings indicate that plasma neopterin, KTR, and CRP are associated with a significantly increased risk of overall cancer. Our study revealed novel evidence regarding the role of IFN-γ-induced inflammation in human carcinogenesis.

HPLC determination of serum pteridine pattern as biomarkers

Pteridinic derivatives are important biomolecules considered as biomarkers for several diseases, especially in cancer and infectious pathologies. A new fluorimetric-HPLC method for the analysis of nine pteridines in human serum has been reported. Two analytical columns composed by C18 porous and fused core particles were assayed and the results compared. Fused core particle column allows us adequate separation, in only one run and in 15 min. Acid precipitation step of the proteins and clean-up process with an Isolute ENV+ (hydroxylated polystyrene-divinylbenzene copolymer) cartridge of the serum samples have been optimized. Analytes were determined by fluorimetric detection, exciting at 272 nm and measuring the fluorescence emission at 410 nm for isoxanthopterin, at 465 nm for xanthopterin, and at 445 nm for the analysis of the other pteridines. Detection limits between 0.07 and 0.61 ng mL(-1) were calculated according to Clayton criterium. Intraday precision varied from 1.2 to 5.3 and interday precision between 1.2 and 7.4, both expressed as RSD (%). External standard and standard addition calibrations were compared in the analysis of serum samples. The pteridine amounts in serum (expressed as ng mL(-1) ± confidence interval) were 3.69 ± 1.78; 1.35 ± 0.24; 0.46 ± 0.14; 0.54 ± 0.24; 0.84 ± 0.55; 2.10 ± 0.51 and 0.23 ± 0.11 for XAN, NEO, MON, ISO, BIO and 6HMPT, respectively, using the external standard method. Comparable results were obtained by the standard addition method. It is noticeable that 7BIO was not detected in the healthy serum samples analyzed.

Urinary neopterin levels in patients with thyroid cancer

Increased urinary neopterin concentrations have been described in many cancers. We aimed to evaluate the urinary neopterin levels in thyroid cancer. Sixty-nine patients with thyroid cancer, 76 patients with benign thyroid pathology and 33 healthy subjects were evaluated. First morning urine samples were collected from the patients and normal subjects for neopterin and creatinine measurement and stored at -80 °C until analysed. Neopterin levels were 149.3 (15.2-1,602.2) μmol/mol creatinine in the malignant group, 32 (5.2-275.6) μmol/mol creatinine in the benign group and 9.2 (2.7-78.7) μmol/mol creatinine in normal subjects (p ≤ 0.001). Urinary neopterin levels were significantly higher in patients with thyroid cancer than patients with benign thyroid pathologies and normal subjects. Also the patients with benign thyroid pathologies had a higher urinary neopterin level than the normal subjects. Malignant group was divided to two groups; patients with/without chronic thyroiditis (confirmed histologically). There were 22 (31.9 %) patients with and 47 (68.1 %) patients without chronic thyroiditis. Urinary levels of neopterin didn't differ in both groups (168.6 (21.3-716.8) μmol/mol creatinine and 135.3 (15.2-1,602.2) μmol/mol creatinine respectively; p = 0.381). Urinary neopterin levels are high in thyroid cancer patients independently from the presence of chronic thyroiditis.

Serum neopterin levels in female dogs with malignant mammary tumours

In this study, we have determined serum neopterin levels in female dogs with primary malignant mammary tumours. The study involved 50 female dogs which had a malignant mammary tumours removed surgically (32 animals with carcinoma, 12 animals with sarcoma and 6 animals with carcinosarcoma) and 10 clinically healthy female dogs. Serum neopterin levels were determined using a commercial ELISA kit. The mean neopterin levels were lower in the malignant tumour groups than in healthy animals but differences were statistically significant only in carcinoma and sarcoma groups. The decrease of neopterin levels in animals with malignant mammary tumours may suggest their decreased cellular immunity. Moreover, it might indicate that decreased activity of cellular mechanisms of the anti-neoplastic response is one of the factors associated with the development and course of malignant mammary tumours in female dogs; however, further studies are necessary.

Serum neopterin, sialic acid and nitric oxide levels in dogs with malignant mammary tumours

Mammary cancer is one of the leading causes of death in pet population. Early diagnosis and malignancy detection is important for prognosis. The levels of neopterin, sialic acid and nitric oxide in serum of dogs with malignant mammary tumours were evaluated to investigate the importance of these biochemical parameters for malign mammary tumour. Twelve healthy dogs and twenty dogs with malignant mammary tumours were used as research materials. Blood samples were collected from both groups for neopterin analysis by enzyme-linked immunosorbent assay, whereas nitric oxide and sialic acid were measured by modified nitrate reductase method and spectrophotometry, respectively. Tissue specimens were evaluated and defined as malignant tumours. Serum nitric oxide and sialic acid levels in dogs with mammary tumours were significantly higher than those in the healthy dogs. Serum neopterin levels were not found significantly different in dogs with mammary tumours compared to healthy dogs. Malignancy of canine mammary tumours are accompained by an elevation of nitric oxide and sialic acid levels.

Serum neopterin is not increased in obese juveniles

Objective. Cardiovascular disease is associated with inflammation and immune activation, concentrations of immune activation markers like neopterin predict outcome in adults. Methods. Serum neopterin concentrations and early metabolic and pre-atherosclerotic symptoms were analyzed in 295 obese juveniles and 101 normal weight controls of similar age. Additionally, the influence of a 12 months weight reduction program on neopterin levels was investigated in 31 obese juveniles. Results. Intima-media thickness of common carotid arteries (IMT) and the concentrations of C-reactive protein (CRP) were increased in the obese juveniles (P < .001). Also triglycerides, oxidized LDL, fasted insulin levels, HOMA-index, leptin, liver transaminases and uric acid were increased compared to the controls. However, serum neopterin was decreased in the obese versus non-obese juveniles (P < .03). The intervention consisting of regular sports, nutritional devices, and a psychologic attendance led after 12 months to an increase of neopterin concentration (P < .05; paired test). Conclusions. Neopterin concentrations in juvenile obesity behaved considerably different from what was demonstrated in adults, levels did not correlate with metabolic and pre-atherosclerotic symptoms found in early phases although early vascular burden and chronic low grade inflammation was indicated by increased IMT and CRP. Neopterin concentrations increased after a 12 months intervention program.

Roles of tetrahydrobiopterin in promoting tumor angiogenesis

Nitric oxide (NO), which is derived from endothelial NO synthase (eNOS), provides crucial signals for angiogenesis in the tumor microenvironment. Tetrahydrobiopterin (BH4) is an absolute requirement for eNOS activity. In this study, we investigated whether this activation is both maintained by a wild-type Ras/phosphatidylinositol 3-kinase (PI3K)/Akt-positive feedback loop in endothelial cells and affects tumor angiogenesis. We found that supplementation of BH4 (via the pterin salvage pathway with Sep) increased Akt/eNOS phosphorylation in both human eNOS-transfected COS-7 cells and endothelial cells concomitant with increases in NO production, cell proliferation, migration, and tube formation. This augmentation was abrogated by a PI3K inhibitor. Sepiapterin (Sep) also increased GTP-bound wild-type Ras and PI3K/Akt/eNOS activation, which was prevented by the eNOS inhibitor, Nω-Nitro-L-arginine methyl ester (L-NAME). Furthermore, expression of GTP cyclohydrolase I (the rate-limiting enzyme in de novo BH4 synthesis) under doxycycline control potentiated in vivo tumorigenesis, tumor cell proliferation, as well as angiogenesis. Conversely, both switching off GTP cyclohydrolase I expression as well as inhibiting its enzymatic activity significantly decreased eNOS expression and tumor vascularization. This study demonstrates an important role for BH4 synthesis in angiogenesis by the activation of eNOS for NO production, which is maintained by a PI3K/Akt-positive feedback loop through effects on wild-type Ras in endothelial cells. Our findings suggest that BH4 synthesis may be a rational target for antiangiogenesis therapy for tumors.

Serum neopterin as a prognostic indicator in patients with breast carcinoma

Neopterin is a useful indicator of the activation state of the cellular immune system, and an elevated level predicts prognosis in different types of tumors. The aim of this study was to evaluate serum neopterin levels if it is viable predictor for prognosis in breast carcinoma patients. Serum neopterin was investigated in 56 breast carcinoma patients, 16 patients with benign breast lesions and 16 healthy women as controls. Neopterin was measured by ELISA (Enzyme-linked immunosorbent assay). The clinicopathological parameters were determined by reviewing both medical charts and pathological records. All patients had been followed-up until September 2009 or death.The mean serum neopterin concentrations were 8.5 ± 5.2 nmol/L in patients with breast carcinoma, 6.5±3.1 nmol/L in patients with benign breast lesion and 8.1 ± 1.9 nmol/L in healthy volunteers (p>0.05). Elevated neopterin levels were significantly correlated with age, elevated serum CRP level, advanced stage and presence of the distant metastases (p<0.05). Overall survival was significantly shorter in patients with a serum neopterin level >10 nmol/L than patients with neopterin <10 nmol/L level (56 months vs. 76 months, p=0.011). Increased preoperative serum neopterin concentrations are associated with a poor prognosis in patients with breast carcinoma.

IDO-Mediated Tryptophan Degradation in the Pathogenesis of Malignant Tumor Disease

Immune escape is a fundamental trait of cancer in which the Th1-type cytokine interferon- γ (IFN-γ) seems to play a key role. Among other tumoricidal biochemical pathways, IFN-γ induces the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) in a variety of cells including macrophages, dendritic cells (DCs) and tumor cells. IDO activity has been shown to reflect the extent and the course in a plethora of malignancies including prostate, colorectal, pancreatic, cervical, endometrial, gastric, lung, bladder, ovarian, esophageal and renal cell carcinomas, glioblastomas, mesotheliomas, and melanomas. Furthermore IDO activity during malignant tumor diseases seems to be part of the tumoricidal immune defense strategy, which in the long run is detrimental to the host, when tryptophan deprivation and production of pro-apoptotic tryptophan catabolites counteract T-cell responsiveness.

Hyperhomocysteinemia and the role of B vitamins in cancer

BACKGROUND

Patients suffering from malignancies have increased complications due to corresponding cardiovascular diseases and risk factor for the development of venous thromboembolism. Epidemiological studies have shown that increased homocysteine plasma concentration (hyperhomocysteinemia) is related to a higher risk of coronary heart disease, stroke, peripheral vascular disease and malignancies. Homocysteine (tHcy) is an intermediate sulfur-containing amino acid produced from methionine during processing of dietary proteins. The plasma homocysteine levels are strongly influenced by diet, as well as by genetic factors. Folic acid, vitamins B6 and B12 are dietary components which influence the plasma homocysteine levels the most. Several studies have found that high blood levels of B vitamins are related to the integrity and function of DNA, and, are at least related to lower concentration of homocysteine. Folate depletion has been found to change DNA methylation and DNA synthesis in both animal and human studies. Because of this critical role of folate, most studies including homocysteine have focused on these two actions.

CONCLUSIONS

Hyperhomocysteinemia proves to be the most common condition highly associated with both venous and arterial thrombosis in many cancer patients, while the associated pathophysiology has not been precisely established yet. Therefore, of current interest is the possible role of folate metabolism developing into a cancer initiating hyperhomocysteinemia. This review will discuss this possibility.

Effect of comorbidity on urinary neopterin in patients with breast carcinoma

Urinary neopterin is increased in less than 20% of patients with breast carcinoma. Moderately increased neopterin concentrations are also known to accompany comorbid conditions commonly observed in patients with breast carcinoma, for example, diabetes mellitus or complications of atherosclerosis. In the present study, we evaluated the effect of the presence of comorbid conditions on urinary neopterin. A trend for higher neopterin concentrations was observed in patients with most of the comorbid conditions, but significantly higher neopterin was observed only in patients aged 70 years or older and in a heterogeneous group of patients with comorbidity other than diabetes mellitus, thyroid disorder, hyperlipidaemia, cardiac disorder or other malignancy. Significantly higher neopterin levels were noted in patients with two or more comorbid conditions. In conclusion, present data demonstrate an association between systemic immune activation reflected in increased urinary neopterin concentrations and age or presence of comorbid diseases in patients with breast carcinoma. A cumulative effect was observed with the presence of two or more comorbid conditions resulting in significantly increased urinary neopterin. These observations should be taken into account when interpreting the changes of parameters of systemic immune and inflammatory response in patients with breast carcinoma.

Urinary Neopterin Levels in Uveitis: Is It a New Activity Marker?

PURPOSE

Neopterin is an immunologic marker for the activation of the cell-mediated immune system and it is found to be elevated in autoimmune diseases. We aimed in this study to investigate the relationship between urinary neopterin levels and disease activity in patients with uveitis.

METHODS

31 patients with active uveitis and 13 patients with inactive uveitis were compared with 27 age and sex matched controls. Disease activity was evaluated by clinical examination and fundus florescein angiography findings. Samples were studied with High Performance Liquid Chromatography.

RESULTS

Urinary neopterin levels in patients with active uveitis, inactive uveitis and control subjects were 274 +/- 98, 179 +/- 61 and 166 +/- 38 micromol/mol creatinine respectively (p < 001). The difference between active uveitis, inactive uveitis and control groups were statistically significant (p < 001).

CONCLUSIONS

Urinary neopterin levels are found to be increased in patients with active uveitis. Neopterin can be used as a biochemical activity marker to support the clinical findings in patients with uveitis.

Neopterin, a prognostic marker in human malignancies

Increased neopterin concentrations are established in patients with an activated cellular (= Th1-type) immune response which includes allograft rejection, viral infection and autoimmune disorders as well as various malignant tumors. In patients with several types of cancer, neopterin concentrations in body fluids like urine, serum/plasma or ascites parallel the course of the disease, and a higher neopterin concentration in patients is an independent predictor of a shorter survival period. Neopterin is released in large amounts from human monocyte-derived macrophages and dendritic cells preferentially following stimulation with the pro-inflammatory cytokine interferon-gamma, thus reflecting the immune activation status. Therefore, not only as a laboratory diagnostic tool, the measurement of neopterin concentrations allows studying the immunological network and its interaction with the pathogenesis of tumor development. It contributes to a better understanding how immune activation is involved in the development of tumor-induced immune escape and tumor antigen specific tolerance.

Inhibitors of indoleamine-2,3-dioxygenase for cancer therapy: can we see the wood for the trees?

Indoleamine-2,3-dioxygenase (IDO) is an immunosuppressive enzyme capable of inhibiting a destructive maternal T cell response against allogeneic fetuses. Expression of IDO is evident in tumours and is thought to enable escape from immunologically mediated rejection. Consequently, clinical trials using an inhibitor of IDO, 1-methyltryptophan (1MT), have been initiated. However, a review of the current literature indicates that we are far from understanding the biological relevance of IDO expression during tumorigenesis. A better understanding of IDO biology is needed to comprehend the effect of IDO inhibitors and to provide a rationale for their therapeutic application in cancer.

Is neopterin level a predictive and differential biomarker in patients with thyroid disorders?

Neopterin production provides information about the extent of cellular immune activation. Measurement of neopterin levels may also provide predictive and prognostic information in patients with malignant thyroid diseases. In the present study, neopterin levels were investigated in patients with thyroid disorders (no.=68). Twenty-four patients had papillary thyroid cancers and the rest of them benign thyroid disorders. Results were compared with a healthy control group (no.=30). It was observed that there was a significant difference in neopterin levels between the control group and the thyroid disorders group (p<0.05). The mean neopterin levels in malignant and benign patients were also significantly different (p<0.05). Monitoring of urinary neopterin profile may be used in early diagnosis of papillary thyroid cancer. Neopterin seems to be a differential biomarker for malignant and benign thyroid disorders.

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.

Inverse association between serum concentrations of neopterin and antioxidants in patients with and without angiographic coronary artery disease

Neopterin is released from human monocyte-derived macrophages upon stimulation with interferon-gamma and is a sensitive indicator for cellular immune activation. Furthermore, reactive oxygen species (ROS) are produced in case of immune activation and inflammation. In a cross-sectional approach, plasma concentrations of neopterin and of antioxidant compounds and vitamins were compared in 1463 patients investigated by coronary angiography, which were recruited within the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study. Serum neopterin concentrations were higher in patients with coronary artery disease (CAD; mean+/-S.D.: 8.7+/-7.3 nmol/L) compared to controls (7.4+/-5.0 nmol/L; Welch's t-test: p<0.001). Mean concentrations of ascorbic acid (p<0.0001), gamma-tocopherol (p<0.05), lycopene (p<0.001), lutein+zeaxanthin (p<0.05), alpha-carotene (p<0.05) and beta-carotene (p<0.05) were lower in CAD than in controls. Neopterin concentrations correlated with CAD-score (r(s)=0.156; p<0.0001) and inversely with antioxidants lycopene (r(s)=-0.277; p<0.0001) and lutein+zeaxanthin (r(s)=-0.175; p<0.0001) levels and with vitamins ascorbic acid (r(s)=-0.207; p<0.0001) and alpha-tocopherol (r(s)=-0.105; p<0.0001). The study demonstrates that higher neopterin production is associated with lower concentrations of antioxidant compounds in patients at risk for atherosclerosis. Results suggest that lower concentrations of antioxidant compounds may relate to higher grade of chronic immune activation in patients.

Diminished quality of life in patients with cancer correlates with tryptophan degradation

PURPOSE

Quality of life (QoL) is frequently impaired in patients suffering from malignant disease. Disturbed metabolism of neurotransmitter serotonin might be crucially involved, and serotonin-precursor tryptophan is degraded during pro-inflammatory immune response. In this study, we compared QoL and fatigue self-rating scores of patients with various types of malignancy with tryptophan metabolic changes and immune activation status.

METHODS

Venous blood was collected from 146 patients with gastrointestinal tumors (n = 43), hematological malignancy (n = 40), gynecological neoplasms (n = 26), lung cancer (n = 20) and from tumors of other localization (n = 17).

RESULTS

QoL was significantly reduced in patients suffering from progressive tumor disease in comparison to stable or remitting disease, also feeling of fatigue was increased (both P < 0.001). Serum tryptophan concentrations were lower in patients with progressive disease (P < 0.01), and decreased tryptophan concentrations were related to decreased QoL (r(s) = 0.256, P < 0.01) and increased fatigue (r(s) = -0.179; P < 0.05). Concentrations of tryptophan and kynurenine and the kynurenine to tryptophan ratio were predictive for impaired QoL and increased fatigue in univariate regression analysis, in multivariate analysis higher ESR and neopterin concentration in combination with stage of disease predicted QoL deterioration.

CONCLUSIONS

Results suggest that immune-mediated tryptophan degradation may contribute to cancer-induced QoL deterioration.

Hyperhomocysteinaemia and immune activation in patients with cancer

BACKGROUND

Recently, homocysteine production was observed in tumour cell lines and homocysteine was proposed as a tumour marker. Furthermore, homocysteine production by activated immunocompetent cells was demonstrated.

METHODS

In this study, homocysteine metabolism and immune activation status were investigated in 128 patients suffering from various types of cancer (haematological disorders, lung cancer, gastrointestinal tumours, gynaecological cancer and tumours of other localisation) and healthy age-matched controls.

RESULTS

A high percentage of patients (39.1%) showed moderate hyperhomocysteinaemia, while cysteine, folate and vitamin B(12) concentrations were within reference ranges. Most patients were found to have elevated concentrations of the immune activation and inflammation markers neopterin and C-reactive protein (CRP), as well as a higher erythrocyte sedimentation rate (ESR). Patients of different cancer groups differed significantly regarding vitamin B(12) and neopterin concentrations; higher B(12) levels were also associated with tumour progression. Univariate regression analysis showed that CRP, ESR and neopterin were suited best to predict death. In multivariate analysis, neopterin was best suited to predicting death, while homocysteine and B vitamins were not associated with patient outcome. Homocysteine concentrations were correlated with folate and cysteine levels. Higher neopterin concentrations coincided with lower folate concentrations, but higher vitamin B(12) concentrations.

CONCLUSIONS

Associations between neopterin and folate concentrations may indicate that cellular immune activation might partly contribute to the development of folate deficiency in cancer patients, thus possibly also impairing homocysteine remethylation.

Neopterin levels during the early phase of human immunodeficiency virus, hepatitis C virus, or hepatitis B virus infection

BACKGROUND

A study was conducted to assess the diagnostic sensitivity of neopterin screening of blood donors with regard to the detection of window-phase specimens of human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) infection.

STUDY DESIGN AND METHODS

In total, 1002 diagnostic window-phase specimens from 98 seroconversion panels (29 HIV-1, 52 HCV, and 17 HBV) were analyzed with viral antigen detection, viral nucleic acid amplification testing (NAT), and neopterin quantitation assays. The study was completed by the analysis of 92 anti-hepatitis B core antigen (HBc)-reactive and 103 alanine aminotransferase (ALT)-elevated blood donor specimens.

RESULTS

A significant association between elevated neopterin concentrations and the very early phase of HIV-1 infection was found. No significant correlation could be observed between neopterin levels and the early phase of HCV or HBV infection. Neopterin concentration was not increased in specimens from blood donors with anti-HBc reactivity or ALT elevation.

CONCLUSIONS

Neopterin screening of blood donors may identify window-phase cases of HIV, but not of HCV or HBV infection. The diagnostic sensitivity of neopterin screening during the HIV window phase is similar to that of the p24 antigen test. With the introduction of viral NATs in blood screening, there is no additional benefit of neopterin screening with regard to the three blood-borne viruses HIV, HCV, and HBV. Acute phases of other infectious agents, however, have been reported to be detected by neopterin enzyme-linked immunosorbent assays.

Neopterin as an indicator of immune activation and prognosis in patients with gynecological malignancies

Malignant tumors may contribute to host response that involves both the adaptive and innate immune systems. Among other biochemical indicators of systemic immune and inflammatory activity, activation of macrophages by interferon-gamma induces a marked increase in the production of neopterin. Neopterin production by activated macrophages is also associated with tryptophan degradation. In addition to tumors of other primary locations, increased urinary and serum neopterin concentrations have been reported in patients with gynecological cancers, including epithelial ovarian carcinoma, cervical carcinoma, endometrial carcinoma, uterine sarcomas, and vulvar carcinoma, but not in women with benign neoplasms or precancerous disorders. Increased neopterin concentrations have been associated with poor prognosis. Elevated levels of neopterin have also been observed in the tumor microenvironment. Systemic (urinary or serum) or local (ascitic fluid) neopterin concentrations increased after therapeutic administration of cytokines. Elevated neopterin concentrations have been associated with anemia of chronic disease and increased urinary zinc loss in patients with gynecological malignancy. Elevated neopterin has also been connected with depressed function of peripheral blood lymphocytes and a decrease in CD4+ T-cell numbers.