Decrease of serum carnitine levels in patients with or without gastrointestinal cancer cachexia

AIM: To evaluate the levels of serum carnitine inpatients with cancer in digestive organs and to comparethem with other cancers in order to provide new insightsinto the mechanisms of cachexia.METHODS: Fifthy-fi ve cachectic patients with or withoutgastrointestinal cancer were enrolled in the presentstudy. They underwent routine laboratory investigations,including examination of the levels of various forms ofcarnitine present in serum (i.e., long-chain acylcarnitine,short-chain acylcarnitine, free carnitine, and totalcarnitine). These values were compared with thosefound in 60 cancer patients in good nutritional status aswell as with those of 30 healthy control subjects.RESULTS: When the cachectic patients with gastrointestinalcancer were compared with the cachecticpatients without gastrointestinal cancer, the differencewas -6.8 μmol/L in free carnitine (P < 0.005), 0.04 μmol/L in long chain acylcarnitine (P < 0.05), 8.7 μmol/L intotal carnitine (P < 0.001). In the cachectic patients withor without gastrointestinal cancer, the difference was12.2 μmol/L in free carnitine (P < 0.001), 4.60 μmol/L inshort chain acylcarnitine (P < 0.001), and 0.60 μmol /Lin long-chain acylcarnitine (P < 0.005) and 17.4 μmol/Lin total carnitine (P < 0.001). In the cachectic patientswith gastrointestinal cancer and the healthy controlsubjects, the difference was 15.5 μmol/L in free carnitine(P < 0.001), 5.2 μmol /L in short-chain acylcarnitine (P< 0.001), 1.0 μmol/L in long chain acylcarnitine (P <0.001), and 21.8 μmol/L in total carnitine (P < 0.001).CONCLUSION: Low serum levels of carnitine in terminalneoplastic patients are decreased greatly due to thedecreased dietary intake and impaired endogenoussynthesis of this substance. These low serum carnitinelevels also contribute to the progression of cachexia incancer patients.