Acetaminophen (APAP) overdose causes acute liver injury and leads to fatal liver damage. However, the therapies are quite limited. Shikonin is a natural product with antioxidant and anti-inflammatory activities. In the present study, the hepatoprotective effects and the underlying mechanisms of shikonin in APAP-induced hepatotoxicity in vivo and in vitro were investigated. APAP-induced acute liver injury and shikonin pretreatment models were established in vivo and in vitro, as evidenced by serum hepatic enzymes, histological changes, oxidative stress indicators and proinflammatory cytokines. The results revealed that shikonin pretreatment prevented the elevation of serum alanine transaminase (ALT), aspartate transaminase (AST) and lactate dehydrogenase (LDH) levels and markedly reduced APAP-induced histological alterations in liver tissues. Additionally, shikonin restored superoxide dismutase (SOD) expression and glutathione (GSH) content in line with the blockade of oxidative stress. The changes in gene expression involved in oxidative stress including methionine sulfoxide reductase (such as MsrA and MsrB1), heme oxygenase-1 (HO-1), SOD2 and cytochrome P450 2E1 (CYP2E1), were markedly reversed after shikonin therapy. Furthermore, shikonin markedly attenuated the APAP-induced production of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) and suppressed the expression of genes related to inflammation. In AML-12 cells, shikonin pretreatment decreased APAP-induced cytotoxicity as measured by CCK-8 assay and LDH release. The changes in gene expression involved in oxidative stress and the inflammatory response were consistent with those in mouse livers. This study indicated that shikonin attenuated APAP-induced acute liver injury via inhibiting oxidative stress and inflammatory responses in vivo and in vitro. These findings offer new insights into the potential therapy for APAP hepatotoxicity.

Caffeine citrate is the drug of choice for the pharmacological treatment of apnea of prematurity. Factors such as maturity and genetic variation contribute to the interindividual variability in the clinical response to caffeine therapy in preterm infants, making the optimal dose administered controversial. Moreover, the necessity for therapeutic drug monitoring (TDM) of caffeine is still worth discussing due to the need to achieve the desired target concentrations as well as concerns about the safety of higher doses. Therefore, we reviewed the pharmacokinetic profile of caffeine in preterm infants, evidence of the safety and efficacy of different doses of caffeine, therapeutic concentration ranges of caffeine and impact of genetic variability on caffeine therapy. Whereas the safety and efficacy of standard-dose caffeine have been demonstrated, evidence for the safety of higher administered doses is insufficient. Thus, preterm infants who lack clinical response to standard-dose caffeine therapy are of interest for TDM when dose optimization is performed. Polymorphisms in pharmacodynamics-related genes, but not in pharmacokinetics-related genes, have a significant impact on the interindividual variability in clinical response to caffeine therapy. For preterm infants lacking clinical response, how to develop individualized medication regimens for caffeine remains to be explored.

Standard-dose caffeine citrate has been routinely prescribed for apnea of prematurity (AOP) management; however, some preterm infants respond well to the therapy while others do not. The AOP phenotype has been attributed solely to the immature control of the respiratory system consequent to preterm birth, but there are also important genetic influences. Based on our previous report, we tested the hypothesis that the human circadian locomotor output cycles kaput (CLOCK) gene polymorphisms play a role in the response to caffeine citrate therapy in preterm infants. We also studied the interactions of the circadian clock with aryl hydrocarbon receptor (AHR) signaling pathways in preterm babies who received caffeine citrate. This single-center study collected data from 112 preterm infants (<35 weeks gestational age) between July 2017 and July 2018, including apnea-free (n = 48) and apneic (n = 64) groups. Eighty-eight candidate single nucleotide polymorphisms (SNPs) were tested using the MassARRAY system. Association analysis was performed using the PLINK Whole Genome Data Analysis Toolset and SNPStats software. Linkage disequilibrium (LD) and haplotype analyses were performed using Hapview software. No significant intergroup differences in allele distributions or genotype frequencies of CYP1A2, CYP3A4, CYP3A5, and CYP3A7 were detected in our study on preterm babies. Two more SNPs in AHR were found to be associated with determining the response to caffeine citrate therapy in our pediatric patients. Of the 46 candidate SNPs in the CLOCK gene, 26 were found to be associated with determining the response to caffeine treatment in these babies. Interestingly, a significant association was retained for 18 SNPs in the CLOCK gene after false discovery rate correction. Moreover, strong LD formed in those variants in AHR, ADORA2A, and CLOCK genes was confirmed to be significantly associated with a better response to standard-dose caffeine therapy. In summary, CLOCK gene polymorphisms play a role in determining the response to caffeine therapy in premature neonates with AOP. However, whether the AHR and CLOCK signaling pathways crosstalk with each other during caffeine treatment remains largely unclear. Future clinical studies including more immature babies and basic research are needed to explore the mechanism by which circadian rhythms affect the response to caffeine therapy.

Oral Bulleyaconitine A (BLA) is effective for treating neuropathic pain in human patients, but the underlying mechanism is poorly understood. Here, we tested whether BLA blocked voltage-gated sodium channels (VGSCs) in dorsal root ganglion (DRG) neurons. Compelling evidence shows that voltage-gated sodium channels are upregulated in uninjured DRG neurons but downregulated in injured ones following peripheral nerve injury. We found that BLA preferably inhibited Na⁺ currents in uninjured DRG neurons in neuropathic rats. Compared to sham rats, IC₅₀ values for resting and inactivated Na⁺ currents were 113 and 74 times lower in injured and uninjured neurons of L4-6 DRGs in spared nerve injury (SNI) rats (4.55 and 0.56 nM) and were 688 and 518 times lower in the uninjured L4 and L6 DRG neurons of L5 spinal nerve ligation (L5-SNL) rats. The use-dependent blockage of BLA on Na⁺ currents was more potent in neuropathic rats compared to sham rats. Bulleyaconitine A facilitated the inactivation of Na⁺ channels in each group. IC₅₀ values for resting and inactivated tetrodotoxin-sensitive (TTX-S) channels were 1855 and 1843 times lower than those for TTX-resistant channels in the uninjured neurons of L5 spinal nerve ligation rats. The upregulation of protein kinase C was associated with the preferable effect of BLA on TTX-S Na⁺ channels in the uninjured DRG neurons. Local application of BLA onto L4-6 DRGs at 0.1 to 10 nM dose-dependently alleviated the mechanical allodynia and thermal hyperalgesia in L5 spinal nerve ligation model. Thus, preferable blockage of TTX-S Na⁺ channels in uninjured DRG neurons may contribute to BLA's antineuropathic pain effect.