Kidney tumors studied by in vitro 1H MRS

V Tugnoli, PhD a, P Taddei, PhD a, A Trinchero, Doctor a, A Reggiani, MD b and MR Tosi, PhD c

aUniversity of Bologna Biochemistry Department, Bologna, Italy b Dipartimento Nefro-Urologico, Policlinico S.Orsola-Malpighi, Bologna, Italy c Istituto di Citomorfologia Normale e Patologica del CNR, Bologna, Italy

Aim: To analyse renal cell extracts by Magnetic Resonance Spectroscopy (MRS) to identify metabolites typical of the human renal parenchyma, renal cell carcinomas (RCCs) and oncocytomas (ONs). Methods: Specimens were collected from 20 patients undergoing surgery for renal masses: 14 RCCs and 6 ONs. Three RCC specimens were obtained from neoplasm, cortex and medulla during radical nephrectomy. Water soluble and lipophilic metabolites from these tissues were studied by 1H MRS. Results: MRS of aqueous extracts yielded information on renal osmolyte markers of physiological renal function. A higher amount of betaine and inositol is distinctive of the medulla, while succinate, trimethylammonium and trimethylammine-N-oxide predominate in the cortex. A large decrease of betaine, trymethylammonium and succinate or the disappearance of inositol and trymethylammine-N-oxide and the appearance of glycine and glutatione are hallmarks of RCC. ONs are benign tumors with a biochemical composition in between healthy and malignant tissue. 1H MRS also identifies the lipid components: cholesteryl oleate is abundant in RCCs and absent in ONs and in healthy tissues. Cholesterol esters may play an important role in cellular proliferation in the malignant tissues. The involvement of the enzymatic system responsible for cholesterol esterification should be further investigated. Conclusions: Detailed information on the biochemical composition of human renal tissues is required for in vivo diagnostic methods, like MRS, based on the detection of molecular markers.

KEY WORDS: Renal tissues, Magnetic Resonance Spectroscopy, Neoplasm.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Diagnostic Markers.