Relationship between Carnitine Pharmacokinetics and Fatigue in Patients Treated with Cisplatin-Containing Chemotherapy

L-Carnitine and Acylcarnitines: Mitochondrial Biomarkers for Precision Medicine

Biomarker discovery and implementation are at the forefront of the precision medicine movement. Modern advances in the field of metabolomics afford the opportunity to readily identify new metabolite biomarkers across a wide array of disciplines. Many of the metabolites are derived from or directly reflective of mitochondrial metabolism. L-carnitine and acylcarnitines are established mitochondrial biomarkers used to screen neonates for a series of genetic disorders affecting fatty acid oxidation, known as the inborn errors of metabolism. However, L-carnitine and acylcarnitines are not routinely measured beyond this screening, despite the growing evidence that shows their clinical utility outside of these disorders. Measurements of the carnitine pool have been used to identify the disease and prognosticate mortality among disorders such as diabetes, sepsis, cancer, and heart failure, as well as identify subjects experiencing adverse drug reactions from various medications like valproic acid, clofazimine, zidovudine, cisplatin, propofol, and cyclosporine. The aim of this review is to collect and interpret the literature evidence supporting the clinical biomarker application of L-carnitine and acylcarnitines. Further study of these metabolites could ultimately provide mechanistic insights that guide therapeutic decisions and elucidate new pharmacologic targets.

Repeated Combined Chemotherapy with Cisplatin Lowers Carnitine Levels in Gastric Cancer Patients

BACKGROUND/AIMS

Carnitine plays an important role in the metabolism of fatty acids. It has also been reported that the administration of anticancer drugs may lead to reductions in serum carnitine levels due to decreased activity of organic cation transporter novel 2, which plays a role in the reabsorption of carnitine in the tubules of the kidney. We therefore studied the change in carnitine levels when chemotherapy was administered repeatedly to patients with gastric cancer.

METHODS

Ten patients with upper gastrointestinal cancer were enrolled in this study between December 2014 and August 2015. All patients were administered chemotherapy consisting of TS-1 and cisplatin every 3 weeks: 3 received it as adjuvant therapy post resection, the remaining 7 received it as treatment for unresectable tumors. Before the start of each chemotherapy cycle, serum was collected.

RESULTS

The mean total carnitine level was 54.5 ± 13.7 μmol/L prior to commencing chemotherapy; it was 46.7 ± 13.5 and 41.4 ± 14.8 μmol/L at the second and third cycles respectively. The total carnitine level was decreased in a statistically significant manner (p = 0.0039). The serum level of total protein and cholinesterase was also decreased significantly (p = 0.0218 and p = 0.0418).

CONCLUSION

Carnitine levels decreased during repeated chemotherapy in patients with gastric cancer, and they are associated with the nutritional status.