Chronic hepatitis B: a critical discussion

Creatine kinase elevation in chronic hepatitis B patients with telbivudine therapy: influence of telbivudine plasma concentration and single nucleotide polymorphisms of TK2, RRM2B, and NME4

PURPOSE

To study the correlations of genetic variants of telbivudine phosphorylase kinases and telbivudine plasma concentration with creatine kinase elevation in chronic hepatitis B patients who received telbivudine.

METHODS

An observational study was performed in China chronic hepatitis B patients receiving telbivudine therapy at 600 mg once daily. Plasma concentration was measured 12 h after taking telbivudine using ultra-performance liquid chromatography-tandem mass spectrometry and SNPs located in RRM2B, TK2, and NME4 was detected by MALDI-TOF mass spectrometry. All statistical analyses were performed with R 4.3.1 and all graphs were drawn by Origin 2023b and P value < 0.05 was considered statistically significant.

RESULTS

A total of 140 patients receiving telbivudine therapy were recruited with a median plasma concentration of 952.49 (781.07-1238.98) ng/mL. The value of plasma concentration was proportional to the grade of creatine kinase elevation and the best telbivudine plasma concentration threshold to discriminate the grade 3/4 CK elevation was 1336.61 ng/mL. Multivariate analysis revealed that plasma concentration and rs3826160 were the independent risk factor of telbivudine-induced creatine kinase elevation. Patients with TC and CC genotype in rs3826160 not only had a higher incidence of creatine kinase elevation but also a higher plasma concentration than TT genotype carriers.

CONCLUSION

Chronic hepatitis B patients with TC and CC genotype in rs3826160 have high telbivudine plasma concentration are at risk of elevated creatine kinase.

The Ca2+/CaMKK2 axis mediates the telbivudine induced upregulation of creatine kinase: Implications for mechanism of antiviral nucleoside analogs' side effect

Telbivudine (LdT), a widely prescribed anti-hepatitis B virus (HBV) drug for the treatment of chronic Hepatitis B (CHB), causes adverse reactions ranging from creatine kinase (CK) elevation to myopathy. The purpose of this study was to explore the mechanism(s) of LdT induced CK elevation. The effects of LdT on mitochondrial morphology and proteins (TK2 and β-actin), oxidative stress, intracellular Ca²⁺ levels, Ca²⁺-related signaling pathway (CaMKK2/AMPK), and Ca²⁺-related biomarkers such as superoxide dismutase (SOD) and malondialdehyde (MDA) were assessed in human skeletal muscle cells (HSKMCs). The results showed that LdT induced a dose-dependent increase in CK activity in HSKMCs, without affecting mitochondrial morphology, and TK2 and β-actin protein levels, following 72 h of treatment. In addition, LdT increased Ca²⁺ production, ROS generation, MDA and lipid peroxide (LPO) levels, and activated the CaMKK2/AMPK signaling pathway. Moreover, these effects were attenuated by the BAPIA-AM (the calcium chelator). We also confirmed the presence of relevant markers (MDA, LPO, and SOD) in serum from CHB patients after LdT treatment, and found that CK was positively correlated with MDA and LPO, and negatively associated with SOD. These findings indicate that LdT induces CK elevation and oxidative stress associated with imbalance of intracellular Ca²⁺ in HSKMCs, suggesting that Ca²⁺/CaMKK2 axis imbalance may underlie human LdT-induced CK elevation. The present findings provide a solid basis for assessing the mechanism of drug-induced CK elevation, which can help develop new tools for the prevention and treatment of diseases associated with drug-induced CK elevation.