Volatile compounds and amino acids in the urine of testicular tumour patients

Abstract

Tumor testisa najčešće je maligno oboljenje u muškaraca mlađe životne dobi. Razvojem tumora nastaju promjene u metabolizmu stanica koje se mogu pratiti analizom metabolita u biološkim uzorcima ispitanika što može biti koristan alat za procjenu stanja organizma i daljnje liječenje bolesti. Cilj ovog istraživanja bio je kreirati kvantitativni profil slobodnih aminokiselina i elemenata u urinu ispitanika s tumorom testisa i odrediti vrijednosti parametara oksidacijsko-redukcijske ravnoteže u krvi. U ispitanika s tumorom testisa izmjerene su značajno povišene koncentracije asparaginske kiseline, mangana i cinka te aktivnost superoksid dismutaze dok su koncentracija treonina, serina, histidina, kobalta i glutationa te ukupni oksidacijski status, bili značajno niži u odnosu na kontrolne ispitanike. Nadalje, provedena je linearna diskriminantna analiza kako bi se ispitalo razdvaja li kreirani profil aminokiselina ispitanike s tumorom testisa od kontrolnih ispitanika, a uspješnost diskriminacije iznosila je 86 %. U urinu ispitanika s tumorom testisa kreiran je i kvalitativni profil hlapljivih organskih metabolita kako bi detektirali koje se vrste, ovisno o funkcionalnim skupinama, javljaju u urinu. Analizom urina u kromatogramu je detektirano oko 200 pikova hlapljivih organskih metabolita te su identificirana 123 metabolita. Procijenjen je učinak kemoterapije cisplatinom na koncentraciju aminokiselina i elemenata te na parametre oksidacijsko-redukcijske ravnoteže. Nakon primljene kemoterapije, u ispitanika s tumorom testisa izmjerene su povišene koncentracije većine aminokiselina i elemenata u urinu te glutationa u krvnoj plazmi u odnosu na vrijednosti prije kemoterapije. Godinu dana nakon kemoterapije rezultati su pokazali slične vrijednosti za većinu aminokiselina osim za treonin, serin i živu koji su bili značajno sniženi, te mangan i platinu koji su i dalje bili značajno povišeni kod ispitanika koji su bolovali od tumora testisa u odnosu na kontrolne ispitanike. Rezultati upućuju na postupni oporavak metabolizma nakon prestanka kemoterapije. Ovim istraživanjem dobiveni su rezultati koji upućuju na to da razvojem tumora u testisima dolazi do poremećaja u ciklusu limunske kiseline i ciklusu uree. Dobiveni rezultati mogu poslužiti kao temelj za daljnja istraživanja o ulozi međuprodukata navedenih ciklusa u tumorigenezi što može pridonijeti eventualnom otkrivanju novih bioloških biljega tumora testisa.Testicular cancer is the most common malignancy in young men and in recent decades its occurrence has been growing rapidly. Tumour development induces changes in cell metabolism that can be monitored by analysing the metabolites in biological samples of the subject. The aim of this study was to create a quantitative profile of free amino acids and elements in urine and levels of oxidative stress parameters in blood of men with testicular cancer and compare them with control subjects. In subjects with testicular cancer, significantly higher concentrations of aspartic acid, manganese and zinc were measured, as well as a higher activity of superoxide dismutase. On the other hand, concentrations of threonine, serine, histidine, cobalt and glutathione and total oxidant status were significantly lower in comparison to control subjects. Additionally, linear discriminant analysis (LDA) was performed to examine whether the created amino acid profile discriminated subjects with testicular cancer from control subjects and the results showed that the discrimination rate was 86%. In the urine of subjects with testicular cancer a qualitative profile of volatile organic metabolites was also created to detect which species, depending on their functional groups, can be detected in urine. GCMS analysis of urine detected about 200 peaks of volatile organic metabolites, and 123 of them were identified. The effect of cisplatin chemotherapy on the concentration of amino acids and elements in urine and on the parameters of oxidative stress was also estimated. After receiving chemotherapy, concentrations of the majority of amino acids and elements in urine and glutathione in blood plasma increased in comparison to values obtained before chemotherapy. One year after receiving chemotherapy the results showed that the concentrations of most amino acids and elements were similar to those measured in the control subjects, except for threonine, serine and mercury, which had significantly higher values, and manganese and platinum, which had significantly lower values than the control subjects. Results indicated a gradual metabolism recover following chemotherapy. The results of this research suggest that the development of a tumour in the testicles leads to a disorder in the citric acid cycle and the urea cycle. The obtained results can be used as a basis for further research on the role of the intermediates of the above-mentioned cycles in tumorigenesis, which could contribute to the possible discovery of new biomarkers for testicular tumours