Vanilmandelic acid and homovanillic acid levels in patients with neural crest tumor: 24-hour urine collection versus random sample

Comparison Between Twenty-Four-Hour Collection and Single Spot Urines for the Detection of Biogenic Amines by High-Performance Liquid Chromatography Tandem Mass Spectrometry

Background

Pheochromocytomas and paragangliomas (PPGL) are neuroendocrine tumors that originate from adrenal medulla or extra-adrenal chromaffin cells, respectively. They produce an excess of catecholamines and their metabolites. Abnormal levels of these biomolecules have been also found in pediatric patients with neuroblastoma (NB). Due to the diurnal fluctuation, the laboratory practice recommends the determination of biogenic amines in acidified 24-h urine samples. However, the collection and acidification of specimens cannot be performed easily, especially for children. Spot urines represent an attractive alternative for the detection of catecholamines and corresponding metabolites.

Methods

In our study, we enrolled 50 patients with symptoms related to PPGL and we determined the concentration values for both spot and 24-h urine samples using high-performance liquid chromatography tandem mass spectrometry (HPLC/MS-MS). Since day variations of the urinary concentration are due to fluctuations in renal excretion rather than in production, we normalized the concentration of biogenic amines in spot urine and in 24-h urine collection to urinary creatinine concentration. A correlation study between the normalized levels of biogenic amines was performed using a linear regression analysis model and Pearson's correlation coefficients.

Results

We obtained a good correlation of values which suggests an interchangeability of the 24-h and random urine samples. Only for epinephrine a weak correlation was determined.

Conclusions

Our findings suggest that the sample collection as single spot urine may replace 24-h collection for the detection of urinary biogenic amines by HPLC/MS-MS.

Correlation between urinary fractionated metanephrines in 24-hour and spot urine samples for evaluating the therapeutic effect of metyrosine: a subanalysis of a multicenter, open-label phase I/II study

We recently conducted an open-label phase I/II study to evaluate the efficacy and safety of preoperative and chronic treatment with metyrosine (an inhibitor of catecholamine synthesis) in pheochromocytoma/paraganglioma (PPGL) in Japan. We compared creatinine-corrected metanephrine fractions in spot urine and 24-hour urine samples (the current standard for the screening and diagnosis of PPGLs) from 16 patients to assess the therapeutic effect of metyrosine. Percent changes from baseline in urinary metanephrine (uMN) or normetanephrine (uNMN) were compared between spot and 24-hour urine samples. Mean percent changes in uMN or uNMN in spot and 24-hour urine were -26.36% and -29.27%, respectively. The difference in the percent change from baseline between uMN or uNMN in spot and 24-hour urine was small (-2.90%). The correlation coefficient was 0.87 for percent changes from baseline between uMN or uNMN measured in spot and 24-hour urine. The area under the receiver operator characteristic (ROC) curve of uMN or uNMN measured in spot urine vs. 24-hour urine (reference standard) to assess the efficacy of metyrosine treatment was 0.93. Correlations and ROCs between 24-hour urinary vanillylmandelic acid, adrenaline, and noradrenaline and 24-hour uMN or uNMN were similar to those between spot uMN or uNMN and 24-hour uMN or uNMN. No large difference was observed between spot and 24-hour urine for the assessment of metyrosine treatment by quantifying uMN or uNMN in Japanese patients with PPGLs. These results suggest that spot urine samples may be useful in assessing the therapeutic effect of metyrosine.

Urinary homovanillic and vanillylmandelic acid in the diagnosis of neuroblastoma: report from the Italian Cooperative Group for Neuroblastoma

BACKGROUND

Urinary homovanillic and vanillylmandelic acid (HVA and VMA) are well known biomarkers for the management of neuroblastoma (NB). Very few and contradictory publications on their diagnostic performance are present in the literature. The aim of this study is to review the results of HVA/Cr and VMA/Cr obtained by the reference laboratory of the Italian Cooperative Group for NB within a 7-year period using HPLC-EC.

PROCEDURE

Updated reference intervals based on age as a continuous variable were calculated by using a multivariate statistical analysis. The diagnostic performance of the two biomarkers has been established by calculating their specificity and sensitivity and by receiver operating characteristics (ROC) curves for different ages and stages of disease.

RESULTS

Accurate age-related reference intervals were obtained from 648 HVA/Cr and 671 VMA/Cr results derived from patients in which the diagnosis of neuroendocrine tumors was excluded. Sensitivity, specificity and ROC curves were obtained from 169 HVA/Cr and 179 VMA/Cr results from confirmed NB patients. The best diagnostic performance was obtained in stage 4S tumors and in children <18months.

CONCLUSIONS

This is the first report, to our knowledge, that analyzes in depth the diagnostic performance of HVA/Cr and VMA/Cr for NB in different stages and age subgroups. In addition, the present work provides cut-off points able to discriminate between NB patients and negative subjects suspected to have NB and could be of help in taking medical decisions.

Interchangeability between 24-hour collection and single spot urines for vanillylmandelic and homovanillic acid levels in the diagnosis of neuroblastoma

The determination of the two urinary catecholamine metabolites homovanillic acid (HVA) and vanillylmandelic acid (VMA) is of crucial importance for the diagnosis and follow-up of neuroblastoma (NB). The standard practice for their measurement requires the use of 24-hour collections that are time consuming and difficult to obtain. In this article, we directly demonstrate that 24-hour collections and single spot urines are interchangeable for the determination of HVA and VMA expressed as ratio on creatinine concentration. This study can be useful for a faster management of NB at onset.

Prediction of primary vs secondary hypertension in children

Despite current guidelines, variability exists in the workup of hypertensive children due to physician preferences. The study evaluates primary vs secondary hypertension diagnosis from investigations routinely performed in hypertensive children. This retrospective study included children 5 to 19 years with primary and secondary hypertension. The proportions of abnormal laboratory and imaging tests were compared between primary and secondary hypertension groups. Risk factors for primary vs secondary hypertension were evaluated by logistic regression and likelihood function analysis. Patients with secondary hypertension were younger (5-12 years) and had a higher proportion of abnormal creatinine, renal ultrasound, and echocardiogram findings. There was no significant difference in abnormal results of thyroid function, urine catecholamines, plasma renin, and aldosterone. Abnormal renal ultrasound findings and age were predictors of secondary hypertension by regression and likelihood function analysis. Children aged 5 to 12 years with abnormal renal ultrasound findings and high diastolic blood pressures are at higher risk for secondary hypertension that requires detailed evaluation.

Analysis of urinary aromatic acids by liquid chromatography tandem mass spectrometry

The separation and detection of 11 urinary aromatic acids was developed using HPLC-MS/MS. The method features a simple sample preparation involving a single-step dilution with internal standard and a rapid 8 min chromatographic separation. The accuracy was evaluated by the recovery of known spikes between 87 and 110%. Inter- and intra-assay precision (CV) was below 11% in all cases and the analytes were observed to be stable for up to 8 weeks when stored at -20 degrees C. The method was validated based upon linearity, accuracy, precision and stability and was used to establish reference intervals for children and adults.

Pediatric urine testing

Today, urinalysis is one of the most common clinical tests ordered for adult and pediatric patients. Because urine specimens are usually readily available and are obtained noninvasively, the urine testing is well suited for children. This article discusses the most common urine tests performed in children for screening purposes and also less common tests for diagnosis of specific disorders. Special considerations regarding urine specimen collection in children are discussed. Some simple tests that are underused by clinicians are mentioned, as are some exciting new molecular applications of urine testing.

Simultaneous HPLC of twelve monoamines and metabolites shows neuroblastoma cell line releases HVA and HIAA

Neuroblastoma is a solid tumor occurring usually in children less than 5 years old. It has been difficult to distinguish neuroblastoma from other childhood tumors through morphological diagnosis. Urine homovanillic acid (HVA), which is a metabolite of dopamine, has been proposed as a diagnostic index. Although increased levels of a serotonin metabolite, 5-hydroxyindole-3-acetic acid (HIAA), have also been observed in urine samples of the patients, they were largely attributed to dietary amines. By using an HPLC system with electrochemical detection, which can simultaneously assay 12 monoamines and metabolites, we showed that HVA and HIAA are two of the most prominent monoamine metabolites in the medium after a neuroblastoma cell line (IMR-32) was cultured for 3 days. Moreover, we found that the levels of HVA and HIAA in the media are proportional to the cell densities. These results suggest that the levels of HVA and HIAA in tissue culture media, or in urine from patients whose dietary amines are well controlled, may provide a valuable diagnostic index for neuroblastoma.