Polyamine reduced diet (PRD) nutrition therapy in hormone refractory prostate cancer patients.

BACKGROUND: Reducing polyamine uptake by selecting low polyamine-containing foodstuffs and reducing bacterial gut production can improve performance status and pain control in hormone refractory prostate cancer (HRPC) patients. Long term PRD observance and tolerance were assessed. Cancer specific survival was studied in function of PRD and time of PRD initiation. METHODS: Twenty-six volunteers, age: 68+/-10 years with metastatic HRPC accepted a polyamine reduced diet and partial gut decontamination with oral neomycin or nifuroxazide (750 mg daily, one week out of two). Time from HRPC to PRD initiation was 10+/-8 months. WHO performance status, EORTC pain scale, body weight, blood counts and serum proteins were regularly assessed. Sixteen other HRPC patients eating a normal diet served as "controls". RESULTS: Mean diet observance is 25+/-24 months. Tolerance is good. WHO performance status and EORTC pain scales were significantly improved respectively at 3 months (0.5+/-0.7 vs 0.7+/-0.9: p=0.03) and 6 months (0.5+/-0.8 vs 1+/-1.3, p=0.02) compared to initial values. Median cancer specific survival times after HRPC and PRD initiation are respectively 36 and 21 months. Eleven PRD patients started the diet before a 9 months cut-off period (after HRPC) and 15 patients after. Median cancer specific survival times for these two groups of patients are respectively 44 and 34 months, p=0.014. Median cancer specific survival times (after HRPC) for PRD patients compared to controls are 36 vs 17 months (p=0.004). CONCLUSIONS: Polyamine-reduced diet is well observed and tolerated. It seems to improve and/or maintain quality of life for HRPC patients. Early PRD initiation in HRPC is promising and may impact favorably cancer specific survival. These results open a rationale for PRD in HRPC management and warrant further investigation.

A simple assay for the measurement of plasma antioxidant status using spontaneous autoxidation of homovanillic acid.

INTRODUCTION: Reactive oxygen species (ROS) contribute to the development of pathophysiological processes, hence the increasing interest in modulating the antioxidant status of patient by nutritional or pharmacological intervention. Antioxidants act by preventing the formation of ROS (inhibitory effect) and/or by trapping these species (scavenger effect). We have developed a simple, sensitive, and reliable test to measure the total antioxidative efficiency of plasma or other biological fluids using microliter samples. METHODS: Autoxidation of homovanillic acid (HVA) gives rise to fluorescent dimers. Antioxidants contained in the plasma (or free aqueous solutions) scavenge the ROS involved in this process and transiently stop the linear increase in fluorescence intensity during a time (delay) proportional to the total concentration of antioxidants and their scavenging efficiency. In addition to this scavenging effect, the kinetics of HVA autoxidation, restarting after the delay, reflects the ability of the plasma antioxidants to inhibit the ROS-triggered autoxidation. RESULTS: The rate of the HVA autoxidation depended on the temperature, the protonation of the phenolic group, and on the presence of peroxide, peroxyl radicals, and peroxidase as well as metal ions. This Fenton-like reaction was transiently stopped by various ROS scavengers including quercetin, ascorbic acid, and thiol derivatives (glutathione and N-acetylcystein) while metal chelating agents such as desferrioxamine, ethylene diamine tetracetic acid (EDTA), and polyamine only reduced its rate. DISCUSSION: The main advantages of this new assay are its versatility to investigate in a single run both the scavenging and inhibitory components of the antioxidant capacity, and its relevance to the reactive hydroxyl radical. As shown in this study, the increase in the antioxidant capacity of human plasma during pharmacological supplementation with antioxidant illustrates one of the various fields of application of this assay.