Functional evaluation of cyclosporine metabolism by CYP3A4 variants and potential drug interactions

Efficacy of tacrolimus versus cyclosporine after lung transplantation: an updated systematic review, meta-analysis, and trial sequential analysis of randomized controlled trials

BACKGROUND

Little data supports using tacrolimus versus cyclosporin for immunosuppression concerning acute rejection and bronchiolitis obliterans syndrome/Chronic Lung Allograft Dysfunction CLAD complications following lung transplantation (LTx). Our goal was to evaluate the use of tacrolimus versus cyclosporine in preventing these complications after LTx.

METHODS

We included randomized controlled trials (RCTs) by searching PubMed, Web of Science, SCOPUS, and Cochrane through January 10th, 2024. We pooled dichotomous data using the risk ratio (RR) and continuous data using the mean difference (MD) with a 95% confidence interval (CI).

RESULTS

We included Four RCTs with a total of 677 patients. Tacrolimus was significantly associated with decreased risk of acute rejection (RR: 1.21, 95% CI [1.03, 1.42], I2 = 25%, P = 0.02) compared with cyclosporine, bronchiolitis obliterans syndrome/CLAD (RR: 1.87, 95% CI [1.26, 2.77], I2 = 52%, P = 0.002), and treatment withdrawal (RR: 3.11, 95% CI [2.06, 4.70], I2 = 0%, P =  < 0.00001). However, tacrolimus significantly increased the risk of new-onset diabetes (RR: 0.33, 95% CI [0.12, 0.91], I2 = 0%, P = 0.03), and kidney dysfunction (RR: 0.79, 95% CI [0.66, 0.93], I2 = 0%, P = 0.006). In contrast, there was no difference in the incidence of all-cause mortality (RR: 91, 95% CI [0.68, 1.22], I2 = 0%, P = 0.53), arterial hypertension (RR: 2.40, 95% CI [0.41, 14.21], I2 = 92%, P = 0.33), and new cancer (RR: 1.57, 95% CI [0.79, 3.10], I2 = 4%, P = 0.20).

CONCLUSION

Tacrolimus has decreased acute rejection episodes and CLAD rate than cyclosporine, but it increased the risk of new-onset diabetes and kidney dysfunction.

Inhibitory effects of calcium channel blockers nisoldipine and nimodipine on ivacaftor metabolism and their underlying mechanism

Ivacaftor is the first potentiator of the cystic fibrosis transmembrane conductance regulator (CFTR) protein approved for use alone in the treatment of cystic fibrosis (CF). Ivacaftor is primarily metabolized by CYP3A4 and therefore may interact with drugs that are CYP3A4 substrates, resulting in changes in plasma exposure to ivacaftor. The study determined the levels of ivacaftor and its active metabolite M1 by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). We screened 79 drugs and 19 severely inhibited ivacaftor metabolism, particularly two cardiovascular drugs (nisoldipine and nimodipine). In rat liver microsomes (RLM) and human liver microsomes (HLM), the half-maximal inhibitory concentrations (IC50) of nisoldipine on ivacaftor metabolism were 6.55 μM and 9.10 μM, respectively, and the inhibitory mechanism of nisoldipine on ivacaftor metabolism was mixed inhibition; the IC50 of nimodipine on ivacaftor metabolism in RLM and HLM were 4.57 μM and 7.15 μM, respectively, and the inhibitory mechanism of nimodipine on ivacaftor was competitive inhibition. In pharmacokinetic experiments in rats, it was observed that both nisoldipine and nimodipine significantly altered the pharmacokinetic parameters of ivacaftor, such as AUC(0-t) and CLz/F. However, this difference may not be clinically relevant. In conclusion, this paper presented the results of studies investigating the interaction between these drugs and ivacaftor in vitro and in vivo. The objective is to provide a rationale for the safety of ivacaftor in combination with other drugs.

Heteroaryl derivatives of suvorexant as OX1R selective PET ligand candidates: Cu-mediated 18F-fluorination of boroxines, in vitro and initial in vivo evaluation

BACKGROUND

The orexin receptor (OXR) plays a role in drug addiction and is aberrantly expressed in colorectal tumors. Subtype-selective OXR PET ligands suitable for in vivo use have not yet been reported. This work reports the development of 18F-labeled OXR PET ligand candidates derived from the OXR antagonist suvorexant and the OX1R-selective antagonist JH112.

RESULTS

Computational analysis predicted that fluorine substitution (1e) and introduction of the fluorobenzothiazole scaffold (1f) would be suitable for maintaining high OX1R affinity. After multi-step synthesis of 1a-1f, in vitro OXR binding studies confirmed the molecular dynamics calculations and revealed single-digit nanomolar OX1R affinities for 1a-f, ranging from 0.69 to 2.5 nM. The benzothiazole 1f showed high OX1R affinity (Ki = 0.69 nM), along with 77-fold subtype selectivity over OX2R. Cu-mediated 18F-fluorination of boroxine precursors allowed for a shortened reaction time of 5 min to provide the non-selective OXR ligand [18F]1c and its selective OX1R congener [18F]1f in activity yields of 14% and 22%, respectively, within a total synthesis time of 52-76 min. [18F]1c and [18F]1f were stable in plasma and serum in vitro, with logD7.4 of 2.28 ([18F]1c) and 2.37 ([18F]1f), and high plasma protein binding of 66% and 77%, respectively. Dynamic PET imaging in rats showed similar brain uptake of [18F]1c (0.17%ID/g) and [18F]1f (0.15%ID/g). However, preinjection of suvorexant did not significantly block [18F]1c or [18F]1f uptake in the rat brain. Pretreatment with cyclosporine A to study the role of P-glycoprotein (P-gp) in limiting brain accumulation moderately increased brain uptake of [18F]1c and [18F]1f. Accordingly, in vitro experiments demonstrated that the P-gp inhibitor zosuquidar only moderately inhibited polarized, basal to apical transport of 1c (p < 0.05) and had no effect on the transport of 1f, indicating that P-gp does not play a relevant role in brain accumulation of [18F]1c and [18F]1f in vivo.

CONCLUSIONS

The in vitro and in vivo results of [18F]1c and [18F]1f provide a solid basis for further development of suitable OXR PET ligands for brain imaging.

Effects of total saikosaponins on CYP3A4 and CYP1A2 in HepaRG cells

Total saikosaponins (TSS) form a group of chemically and biologically active components that can be extracted from Bupleurum, with reported antidepressive, anti-inflammatory, antiviral, antiendotoxin, antitumor, anti-pulmonary fibrosis and anti-gastric ulcer effects. Bupleurum or TSS is frequently utilized in clinical practice alongside other medications (such as entecavir, lamivudine, compound paracetamol and amantadine hydrochloride capsules), leading to an increased risk of drug-drug interactions. The cytochrome P450 (CYP) family serves a critical role in the metabolism of numerous essential drugs (such as tamoxifen, ibuprofen and phenytoin), where the majority of drug interactions involve CYP-mediated metabolism. It is therefore essential to understand the effects of key components of Bupleurum on CYPs when administering combination therapies containing TSS or Bupleurum. The present study aimed to investigate the effects of TSS on the mRNA and protein expression of CYP3A4 and CYP1A2 in HepaRG cells. The effects of TSS on the survival of HepaRG cells was investigated using the Cell Counting Kit-8 (CCK-8) method. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot (WB) analysis were used to assess the effects of different concentrations of TSS (0, 5, 10 and 15 µg/ml) on CYP3A4 and CYP1A2 mRNA and protein expression in HepaRG cells. Based on the CCK-8 assay results, it was observed that the cell viability remained above 80% when treated with 1, 5, 10 and 15 µg/ml TSS. Although there was a statistically significant reduced cell viability at TSS concentrations of 10 and 15 µg/ml compared with the control group, the findings indicated that TSS did not exhibit notable cytotoxic effects at these concentrations. Furthermore, RT-qPCR results revealed that compared with those in the control group, TSS at concentrations of 10 and 15 µg/ml reduced CYP3A4 mRNA expression but increased CYP1A2 mRNA expression in HepaRG cells at concentrations of 15 µg/ml. WB analysis found that TSS at concentrations of 10 and 15 µg/ml downregulated CYP3A4 protein expression in HepaRG cells while increasing CYP1A2 protein expression at concentrations of 15 µg/ml. Results in the present study suggest that TSS can inhibit CYP3A4 mRNA and protein expression, but exerts opposite effects on their CYP1A2 counterparts. These findings suggest that it is necessary to consider drug interactions between clinical preparations containing TSS or Bupleurum and drugs metabolized by CYP3A4 and CYP1A2 to avoid potential adverse drug reactions in clinical practice.