Erythrocyte polyamines: their diagnostic and therapeutic importance in human neuro-oncology

The prognostic value of erythrocyte polyamines in the preoperative evaluation of patients with renal cell carcinoma

INTRODUCTION

Polyamines, spermine and spermidine, are ubiquitous polycationic structures, which are essential for cell proliferation and differentiation. We tested whether spermine and spermidine could improve the prognostic ability of six established preoperative predictors of cancer-specific mortality (CSM) after partial or radical nephrectomy for renal cell carcinoma (RCC).

MATERIALS AND METHODS

Overall, 385 patients with clinical stages T(1-3), M(0-1) RCC were treated with radical or partial nephrectomy at a single institution between 1990 and 2007. Kaplan-Meier plots depicted CSM after stratification according to spermine and spermidine levels (dichotomised to above and below the median value). Univariable and multivariable Cox regression models tested the prognostic ability of continuously coded spermine and spermidine levels in preoperative CSM predictions. Covariates consisted of pre-treatment T stage, M stage, age, gender and symptom classification.

RESULTS

The 5-year CSM-free survival of patients with spermine levels < or =4.5 and >4.5 nmol/8x10(9) erythrocytes were, respectively, 79.5% and 65.0%. Similarly, the 5-year CSM-free survival of patients with spermidine levels < or =9.0 and >9.0 nmol/8x10(9) erythrocytes were, respectively, 81.1% and 63.7%. In multivariable analyses addressing CSM after surgery, both spermine (p< or =0.002) and spermidine (p< or =0.001) achieved independent predictor status and improved the accuracy of established preoperative CSM predictors by 2.1% (p<0.001).

CONCLUSIONS

Circulating polyamine levels may significantly improve the prognostic value of established determinants of CSM in patients with RCC of all stages prior to nephrectomy. External validation of our findings is required prior to implementation in clinical practice.

Determination of dansylated polyamines in red blood cells by liquid chromatography-tandem mass spectrometry

The concentration of polyamines in red blood cells (RBCs) is considered to be an index of cell proliferation. This index has been demonstrated to be of clinical importance for the follow-up and treatment of some cancer patients. The concentration of polyamines in RBCs is usually determined by high-performance liquid chromatography (HPLC) with fluorescence detection. In the current work, we present a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of putrescine, spermidine, and spermine, the three major polyamines in RBCs. The polyamines were dansylated and analyzed by an LC gradient of 20-min duration on a C18 column on-line with a tandem mass spectrometer. An internal standard (1,8-diaminooctane) was used for quantification. This method exhibited excellent linearity for the three polyamines with regression coefficients higher than 0.99. The limits of detection for putrescine, spermidine, and spermine were 0.10, 0.75, and 0.50 pmol/ml, respectively. The intrarun precision values for putrescine, spermidine, and spermine all were better than 10%, and the interrun precision values were 13%, 9%, and 20%, respectively. The LC-MS/MS method is sufficiently simple and reliable enough to replace the currently used HPLC method with fluorescence detection in which putrescine is not always detectable.

Quantification of polyamines in human erythrocytes using a new near-infrared cyanine 1-(ε-succinimidyl-hexanoate)- 1′-methyl-3,3,3′,3′-tetramethyl- indocarbocyanine-5,5′-disulfonate potassium with CE-LIF detection

A novel near-infrared (NIR) cyanine 1-(epsilon-succinimidyl-hexanoate)-1'-methyl-3,3,3',3'-tetramethyl-indocarbocyanine-5,5'-disulfonate potassium (MeCy5-OSu) has been developed in our laboratory. Simultaneous determination of MeCy5-OSu-derivatized polyamines spermine (Spm), spermidine (Spd), cadaverine (Cad), and putrescine (Put) based on the separation by CE combined with diode LIF detection has been accomplished. The highest derivatization efficiency was achieved in 0.2 mol/L borate buffer (pH 8.8) for 20 min at 25 degrees C. Polyamine derivatives were separated within 14 min in the phosphate running buffer (pH 3) containing 50 mmol/L phosphoric acid, 40 mmol/L SDS, and 35% methanol v/v. Linearity of response was obtained in the range of 10-200 nmol/L. The detection limits (S/N = 3) for Spm, Spd, Cad, and Put were 0.8, 1, 3, and 2 nmol/L, respectively. The proposed method has been successfully applied to the analysis of polyamines in erythrocytes of two healthy persons and one cancer patient. Average recoveries for erythrocyte samples were 93.6-106% and coefficients of variation ranged from 1.8 to 5.4%. The analysis of polyamines in erythrocytes can be used for studying the relationship between their changes and the carcinogenesis process involved in erythrocytes.

Increased red blood cell polyamines in ALS and Parkinson's disease

The polyamines spermidine (SPD) and spermine (SPM) are implicated in nerve cell degeneration and regeneration. Over 70% of circulating polyamines are associated with red blood cells (RBC). Against this background we have analysed RBC polyamines in two neurodegenerative disorders, amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). Twenty patients with the sporadic form of ALS, 20 patients with PD, and 20 healthy controls were studied. The highest levels of SPD and SPM were found in the PD group where the mean values were 134 and 115%, respectively, above those of the controls. The patients with PD also presented the lowest levels of the SPD precursor, putrescine (PUTR). In the patients suffering from ALS the SPD and SPM mean levels were increased by 46 and 112%, respectively. The RBC SPD/SPM ratio in the patients suffering from PD was significantly elevated in comparison with that of ALS patient group, suggesting a different involvement of the polyamine system in these disorders. It is at present unknown if raised polyamine levels may contribute to induce the degeneration of susceptible neurons or if the increase represents a compensatory protective reaction, or simply an unspecific epiphenomenon.

Reproducibility of erythrocyte polyamine measurements and correlation with plasma micronutrients in an antioxidant vitamin intervention study

Erythrocyte polyamine measurements have been previously investigated as candidate biomarkers for hyperproliferation and recently as a potential intermediate endpoint in clinical chemoprevention trials with difluoromethylornithine, an inhibitor of polyamine biosynthesis. This study was performed to determine the reproducibility of erythrocyte polyamine measurements and their possible correlation with plasma micronutrients in seven healthy adults in an antioxidant vitamin intervention study. As part of this cross-over intervention study, three subjects took beta-carotene (31.4 mg/day) plus D-alpha-tocopherol acetate (720 IU/day) supplements during the first 3 months and four subjects took the supplements during the second 3 months. Heparinized blood samples were collected at baseline and every month over total 6 months for simultaneous determination of erythrocyte polyamines and plasma micronutrients by the high-performance liquid chromatographic method. For all the measures of erythrocyte polyamines the intraindividual variation was smaller than that between subjects, and three or four measurements required to accurately characterize long-term erythrocyte polyamines for an individual. The intra-class correlations were moderately high for all erythrocyte polyamine measurements, indicating a good reproducibility for intra-individual erythrocyte polyamine measurements. Based on monthly values, significant inverse correlations were found between erythrocyte spermidine and the plasma levels of retinol (r = -0.50) and lutein (r = -0.52). There were also significant inverse associations between erythrocyte spermine and plasma levels of alpha-tocopherol (r = -0.29), lutein (r = -0.44), lycopene (r = -0.29), beta-cryptoxanthin (r = -0.30), and total carotenoids (r = -0.29). The effects of supplementation upon the associations between erythrocyte polyamines and plasma nutrient levels were additionally addressed. The results indicate an acceptable longitudinal reproducibility of erythrocyte polyamine measurements, support the hypothesis that erythrocyte polyamine measurements may be correlated with plasma levels of certain nutrients, and suggest a further biomarker application in cancer prevention trials involving dietary modifications or specific relevant micronutrients.

On the degradation and elimination of spermine by the vertebrate organism

1. Treatment of mice and rats with the polyamine oxidase inhibitor N1,N4-bis-(2,3-butadienyl)-1,4-butanediamine (MDL 72527) causes a gradual accumulation of spermine in the circulation and a decrease of spermidine concentration. 2. Spermine is mainly localized in the red blood cells. 3. Co-administration of 2-(difluoromethyl)ornithine and MDL 72527 enhances considerably the rate and extent of spermine accumulation in the circulation. 4. It is assumed that the increased rate of spermine accumulation by the two drugs is due to the enhancement of cell death, i.e. spermine accumulation is the result of its release into the circulation from dying cells, not due to physiological release. 5. After discontinuation of polyamine oxidase inhibition spermine appears to be gradually transformed into spermidine by red blood cell polyamine oxidase, obviously without transformation into N1-acetylspermine.

Erythrocyte polyamine levels in human prostatic carcinoma

Abnormally high red blood cell polyamine levels were found in benign prostatic hyperplasia and in prostatic adenocarcinoma patients. In prostatic adenocarcinoma patients a relationship was noted between the importance of red blood cell spermidine and spermine concentrations, and the clinical stage of the disease (Whitmore classification). Considering prostatic adenocarcinoma patient populations, patients with metastases (groups 3 and 4) statistically differed from those without metastases (group 2). Furthermore, red blood cell polyamine level determination discriminated patients in the hormonal escape group (group 4) from those usually considered as hormone responsive (groups 2 and 3). No statistically significant correlation was observed between red blood cell polyamine levels and usual tumor markers (prostatic acid phosphatase and prostate specific antigen). These results confirmed that red blood cell polyamine levels must be considered as a circulating index of cell proliferation that might be of clinical importance during the long-term followup and treatment of prostatic adenocarcinoma patients.

Red blood cell polyamine level changes following heart transplantation in man

Follow-up of orthotopic heart transplanted patients has revealed the existence of abnormally high red blood cell (RBC) spermidine (Spd) levels during the first two months after surgical procedure (A-period). From the third month after heart transplantation (B-period), RBC Spd concentrations went back to normal values in early cardiac rejection (ECR) patients. During A- and B-periods, significantly higher Spd levels and Spd/Spm ratios were observed in late cardiac rejecting (LCR) patients than in ECR ones. The lack of a direct relationship between the histological grade of rejection and RBC Spd levels leads us to consider these polyamine blood levels as a new biological instrument in the diagnosis of heart rejection.