Endocrine effects of erythropoietin in cancer patients.

The recent advances in the knowledge of the psychoneuroimmunological pathogenesis of human neoplasms have demonstrated the existence of feed-back mechanisms operating between interleukins and endocrine secretions, which play an important role in the regulation of the immune responses, including the anticancer immunity. In contrast, few studies only have been performed to investigate the possible relation between endocrine activities and hematopoietic growth factors. The present study was performed to analyze the acute endocrine effects of erythropoietin-alpha (EPO) on the main endocrine secretions. The study was carried out in 10 advanced solid tumor patients. EPO was injected subcutaneously at a dose of 10,000 U, and venous blood samples were collected before and 2, 4 and 6 h after EPO administration. No significant changes in mean serum levels of FSH, LH and TSH were seen in response to EPO. Cortisol and DHEAS concentrations increased after EPO injection, whereas those of PRL decreased, but none of these differences was statistically significant. Finally, mean serum levels of both growth hormone (GH) and somatomedin-C (IGF-1) significantly decreased after EPO administration. This preliminary study shows that EPO may inhibit GH secretion from the pituitary gland and IGF-1 production. Since GH would stimulate EPO release, the results of this study may suggest the existence of feedback mechanism operating between GH secretion and EPO production, with inhibitory effect of EPO on GH secretion, and stimulatory action of GH on EPO production. Therefore, this study would describe the first example of hemato-endocrine feedback mechanisms. Moreover, this study, by showing an inhibitory effect of EPO on IGF-1 secretion, would suggest a possible use of EPO in the medical oncology not only for the treatment of cancer related anemia, but also to counteract tumor growth by blocking IGF-1 production, which has been proven to be a growth factor for several tumor histotypes. Obviously, IGF-1 is not the only tumor growth factor, but it could play a fundamental role in the regulation of production and activity of several other tumor growth factors. In any case, this study describes the only acute endocrine effects of EPO. Therefore, further studies, by evaluating the endocrine effects of a chronic treatment with EPO, will be required to establish which may be its effect on IGF-1 endogenous production, and its consequence on survival time.

Reduction of cisplatin-induced anemia by the pineal indole 5-methoxytryptamine in metastatic lung cancer patients.

OBJECTIVE: It has been demonstrated that the hematopoiesis is under a neuroendocrine control, namely mediated by the pineal gland. The pineal indole melatonin (MLT) has appeared to exert thrombopoietic and lymphopoietic activity, whereas it has no relevant effect on red cell differentiation. The present study was performed to evaluate the influence of another pineal indole, the 5-methoxytryptamine (5-MTT) on red cell line and hemoglobin production. MATERIALS & METHODS: The study was carried out in metastatic lung cancer patients who underwent a chemotherapeutic combination containing cisplatin, which is known to induce anemia. The study included 20 patients treated with cisplatin plus etoposide, who were randomized to receive chemotherapy alone or chemotherapy plus 5-MTT (1 mg/day orally at noon every day). RESULTS: Hemoglobin mean blood concentrations significantly decreased in both groups of patients. However, the decrease in hemoglobin levels observed in patients treated with chemotherapy alone was significantly higher with respect to that observed in patients concomitantly treated with 5-MTT. Moreover, the percent of patients who had no progressive disease on treatment was significantly higher in the group treated with chemotherapy plus 5-MTT. CONCLUSIONS: Even though the low number of patients does not allow us to draw define conclusions, these preliminary results would show that the concomitant administration of 5-MTT may reduce cisplatin-induced anemia in cancer patients, by suggesting a hematopoietic activity of 5-MTT on red cell line differentiation and hemoglobin production. Moreover, the study would suggest that 5-MTT, as well as previously demonstrated for MLT, may also enhance the cytotoxic activity of cancer chemotherapy.