Cyclosporine Metabolites' Metabolic Ratios May Be Markers of Cardiovascular Disease in Kidney Transplant Recipients Treated with Cyclosporine A-Based Immunosuppression Regimens

Chronic Inflammatory Status Observed in Patients with Type 2 Diabetes Induces Modulation of Cytochrome P450 Expression and Activity

Diabetes mellitus is a metabolic disease that causes a hyperglycemic status which leads, over time, to serious damage to the heart, blood vessels, eyes, kidneys and nerves. The most frequent form of diabetes is type 2 diabetes mellitus (T2DM) which is often part of a metabolic syndrome (hyperglycaemia, hypertension, hypercholesterolemia, abdominal obesity) that usually requires the use of several medications from different drug classes to bring each of these conditions under control. T2DM is associated with an increase in inflammatory markers such as interleukin-6 (IL-6) and the tumor necrosis factor alpha (TNF-α). Higher levels of IL-6 and TNF-α are associated with a downregulation of several drug metabolizing enzymes, especially the cytochrome P450 (P450) isoforms CYP3As and CYP2C19. A decrease in these P450 isoenzymes may lead to unexpected rise in plasma levels of substrates of these enzymes. It could also give rise to a mismatch between the genotypes determined for these enzymes, the predicted phenotypes based on these genotypes and the phenotypes observed clinically. This phenomenon is described as phenoconversion. Phenoconversion typically results from either a disease (such as T2DM) or concomitant administration of medications inducing or inhibiting (including competitive or non-competitive inhibition) a P450 isoenzyme used by other substrates for their elimination. Phenoconversion could have a significant impact on drug effects and genotypic-focused clinical outcomes. As the aging population is exposed to polypharmacy along with inflammatory comorbidities, consideration of phenoconversion related to drug metabolizing enzymes is of importance when applying pharmacogenomic results and establishing personalized and more precise drug regimens.

Low Content of Cyclosporine A and Its Metabolites in the Colostrum of Post-Transplant Mothers

The rate of post-transplant mothers who breastfeed while on immunosuppression is progressively increasing. Data on breastfeeding while on cyclosporine-based regimens are limited. Therefore, we assessed the amount of cyclosporine and its metabolites that might be ingested by a breastfed infant by measuring the concentration of cyclosporine and its metabolites in the colostrum of seven post-transplant mothers. The mean concentration of cyclosporine in the colostrum was 22.40 ± 9.43 mcg/L, and the estimated mean daily dose of the drug was 1049.22 ± 397.41 ng/kg/24 h. Only three metabolites (AM1, DHCsA, and THCsA) had mean colostrum amounts comparable to or higher than cyclosporine itself, with the daily doses being 468.51 ± 80.37, 2757.79 ± 1926.11, and 1044.76 ± 948.56 ng/kg/24 h, respectively. Our results indicate a low transfer of cyclosporine and its metabolites into the colostrum in the first two days postpartum and confirm the emerging change to the policy on breastfeeding among post-transplant mothers. A full assessment of the safety of immunosuppressant exposure via breastmilk will require further studies with long-term follow-ups of breastfed children.

Higher Concentrations of Cyclosporine Metabolites in Liver Transplant Recipients With a History of Viral and Bacterial Infections

BACKGROUND

Infection remains a serious clinical problem in liver transplant (LTX) recipients. A higher risk of infection is connected with immunosuppression therapy. The aim of the study was to assess the relationships between infections' incidence and concentrations of cyclosporine (CsA) metabolites after LTX.

METHODS

Forty-three liver transplant recipients receiving CsA were included in the study. With the use of liquid chromatography combined with tandem mass spectrometry, concentrations of CsA and its metabolites were measured: dihydroxylated cyclosporine metabolites (DiHCsA), trihydroxylated cyclosporine metabolites (TriHCsA), demethylcarboxylated cyclosporine metabolites (DemCarbCsA), AM1, AM9, and AM4N. The study protocol conformed with the Declaration of Helsinki.

RESULTS

Patients with a history of Epstein-Barr virus (EBV) infection had higher DiHCsA, TriHCsA, DemCarbCsA, AM1/CsA, DiHCsA/CsA, TriHCsA/CsA i DemCarbCsA/CsA in comparison with group without such infection (P = .049, P = .037, P = .006, P = .018, P = .005, P = .027, and P = .026, respectively). LTX recipients with a history of all viral infections had higher DiHCsA, TriHCsA, DiHCsA/CsA, TriHCsA/CsA than patients without viral infections (P = .013, P = .021, P = .013, and P = .048, respectively). Multivariable analysis showed that AM1, DiHCsA, TriHCsA, DemCarbCsA, AM4N/CsA had positively influence on the incidence of all viral infections (β = 0.0302, P = .0328; β = 0.0699, P = .0453; β = 0.6781, P = .0382; β = 0.6767, P = .0414; and β = 0.8307, P = .0267, respectively). In multivariable analysis, patients with a history of all bacterial infections had higher AM1 and higher AM1/CsA in comparison with LTX recipients without such infections (β = 0.0118, P = .0279; and β = 0.0099, P = .036, respectively).

CONCLUSION

In liver transplant recipients with a history of viral or bacterial infections higher concentrations of CsA metabolites were found. Possibly CsA metabolites could be used to assess the risk of infection in patients after liver transplantation. It should be confirmed in further investigations.

Comparative pharmacokinetics of verapamil and norverapamil in normal and ulcerative colitis rats after oral administration of low and high dose verapamil by UPLC-MS/MS

In this study, UC rat model was established by administration of 5% (w/v) dextran sulfate sodium, and the pharmacokinetics of verapamil and norverapamil were evaluated in normal and UC rats using UPLC-MS/MS after oral administration of 5 mg/kg and 50 mg/kg verapamil.The peak concentration (C_max) and the area under plasma concentration-time curves (AUC) of verapamil in UC rats after oral administration of 5 mg/kg were significantly greater (2.5 times and 2 times, respectively) than those in normal rats, but the clearance rate (Cl) was significantly lower (by 50%). For norverapamil, C_max and AUC were significantly greater (2.8 times and 2.5 times, respectively), and Cl was significantly lower (by 45%). But, pharmacokinetic parameters of verapamil and norverapamil after oral administration of 50 mg/kg were no significant differences between UC and normal rats.The better absorption and poor excretion for low-dose verapamil may be attributed to down-regulation of P-gp expression in the intestine and kidney. No significant differences of pharmacokinetic parameters for high-dose verapamil may be explained as the saturation of an efflux mechanism.The findings of this study suggested that in UC patients, doses of verapamil should be decreased when low-dose verapamil was orally administrated.