Systemic alterations in phospholipid concentrations of blood plasma in patients with thyroid carcinoma: an in-vitro (31)P high-resolution NMR study

Abstract

In this study in-vitro (31)P high-resolution NMR spectroscopy of human blood plasma was optimized to obtain absolute concentrations of the major plasmaphospholipids: phosphatidylethanolamine plus sphingomyelin (PE + SM), 1- and 2-acyl-lysophosphatidylcholine (LPC1 and LPC2), phosphatidylinositol (PI) and phosphatidylcholine (PC). Plasma spectra of 33 patients with thyroid carcinoma were acquired at 121.49 MHz using a 300 MHz spectrometer. The patients were rendered hypothyroid (TSH >30 mU/l) in preparation for a whole-body scintigraphy. The whole-body scintigraphy showed tumour tissue or metastases in 16 patients (group C). Owing to an inconclusive whole-body scintigraphy, 17 patients were classified as being in remission (group B). After levothyroxine substitution 14 patients of group B were measured in euthyroidism too (group D). Besides these sub-groups, there was a control group made up of 23 healthy volunteers (group A). Group B showed significantly higher PE + SM and PC concentrations than group C (0.59 +/- 0.02 mmol/l PE + SM in B vs 0.48 +/- 0.02 mmol/l in C; 2.1 +/- 0.1 mmol/l PC in B vs 1.6 +/- 0.1 mmol/l in C). In comparison with group D higher concentrations of the phospholipids PE + SM and PC as well as PI were found in group B (0.59 +/- 0.02 mmol/l PE + SM in B vs 0.48 +/- 0.03 mmol/l in D; 0.074 +/- 0.005 mmol/l PI in B vs 0.046 +/- 0.004 mmol/l in D; 2.1 +/- 0.1 mmol/l PC in B vs 1.6 +/- 0.1 mmol/l in D). The data indicate that under the condition of hypothyroidism only patients in remission (group B) show significantly increased phospholipid concentrations, whereas the values in patients with remaining tumour tissue (group C) do not differ from those of the reference groups A and D. This finding is interpreted as an interference between the hormonal status and the systemic effects of cancer.