Učinak farmakogenetičkih varijacija UGT1A9, CYP3A4 i CYP3A5 na farmakokinetiku mikofenolne kiseline primijenjene s ciklosporinom ili takrolimusom u bolesnika s presađenim bubregom

doctoral thesis

• Title (english): Effect of pharmacogenetic variants of the UGT1A9, CYP3A4 and CYP3A5 on pharmacokinetic of mycophenolic acid administered in commedication with cyclosporine or tacrolimus in renal transplant recipients
• Author: Ana Borić Bilušić
• Mentor: Karmela Barišić (mentor)
• Committee member: Mila Lovrić (predsjednik povjerenstva)
• Committee member: Mario Laganović (član povjerenstva)
• Committee member: Jelena Osmanović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of medical biochemistry and haematology); Zagreb
• Defense date and country: 2023-12-22, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Medical Biochemistry
• Universal decimal classification (UDC): 615 - Pharmacology. Therapeutics. Toxicology

Abstract

Cilj je ovoga istraživanja ispitati utjecaj polimorfizama metaboličkih enzima UGT i CYP te
ABC transportera na bioraspoloživost mikofenolne kiseline (MPA) u stanju dinamičke
ravnoteže primijenjene u kombinaciji s ciklosporinom (CsA) ili takrolimusom (TAC) kod
bolesnika s transplantiranim bubregom. Analizirana je povezanost genske varijabilnosti
metaboličkog enzima UGT1A9 te membranskog prijenosnika ABCG2 s bioraspoloživosti
MPA-a. Dodatno je provedena i analiza utjecaja genske varijabilnosti metaboličkih enzima
CYP3A4 i CYP3A5 s koncentracijama CsA-a i TAC-a te su procijenjeni dometi interakcije
MPA-a s CsA-om i TAC-om u odnosu na ispitane varijante gena ABCG2 u bolesnika s
transplantiranim bubregom. U istraživanje je bilo uključeno je 68 bolesnika (n=68,
muškarci=35, dob 16-71) na standardnom imunosupresivnom protokolu koji uključuje MPA,
CsA ili TAC te kortikosteroide. Uzorci krvi uzeti su tjedan dana nakon početnoga doziranja.
Uzorak krvi za određivanje ostatnih koncentracija MPA, CsA i TAC-a, uzet je u 8h ujutro prije
jutarnje doze lijeka nakon čega je uslijedila standardna jutarnja doza. Tijekom 12-satnoga
intervala doziranja za MPA je uzeto 6 uzoraka krvi za određivanje koncentracije MPA. MPA
je analizirana HPLC metodom, a genotipizacija polimorfizama UGT1A9 -2152C>T i -275 T>A,
CYP3A4*22, CYP3A5*3, ABCG2 c.421C>A, ABCC2 24 C>T i 1249 G>A, ABCB1
2677G>T/A, 3435C>T, 1236C>T, SLCO1B1 c.521T>C je provedena metodom lančane
reakcije polimeraze u stvarnom vremenu (qPCR). Bolesnici homozigoti divljega tipa i nositelji
varijantnoga alela ABCG2 c.421C>A ujednačeni su metodom egzaktnoga uparivanja u
kombinaciji s optimalnim potpunim uparivanjem u odnosu na demografske, biofarmaceutske i
genetičke varijable te je procijenjen učinak varijantnoga alela (frequentist, Bayes) usporedbom
omjera geometrijskih srednjih vrijednosti (GMR) farmakokinetičkih parametara MPA
ujednačenih prema dozi u stanju dinamičke ravnoteže. Dobiveni rezultati ukazuju na značajnu
povezanost varijantnoga alela ABCG2 c.421C>A i farmakokinetike MPA-a. Kod stabilnih
bolesnika s transplantiranim bubregom koji su ujedno i nositelji varijantnoga alela ABCG2
c.421C>A, rezultati ukazuju na povećanu bioraspoloživost MPA (AUCτ,ss ≈ 40 %) u skladu s
proporcionalno smanjenim klirensom (CLT/F,ss ≈ 30 %). Dodatno je uočena značajna uloga
polimorfizma ABCG2 c.421 C>A u moduliranju interakcije CsA-a i TAC-a s MPA-a. Rezultati
upućuju na znatno izraženiji učinak varijantnoga alela ABCG2 c.421C>A u skupini bolesnika
na terapiji TAC-om kod kojih je zabilježena dva puta veća bioraspoloživost MPA, manji klirens
i manja brzina apsorpcije u odnosu na skupinu bolesnika na terapiji CsA-om. Rezultati nisu
pokazali utjecaj ispitivanih polimorfizama metaboličkog enzima UGT1A9 na koncentracije
MPA-a. Također nije zabilježen ni značajan utjecaj polimorfizama enzima CYP3A4 i CYP3A5
na koncentracije CsA-a i TAC-a, moguće zbog malog broja bolesnika nositelja varijantnih
alela.

Abstract (english)

The aim of this research was to analyse the influence of metabolic enzymes UGTs, CYPs and
ABCs transporter polymorphism on steady-state mycophenolic acid (MPA) exposure applied
in commedication with cyclosporine (CsA) or tacrolimus (TAC) in renal transplant recipients.
The association between the genetic variability of the metabolic enzyme UGT1A9 and the
membrane transporter ABCG2 and the MPA bioavailability was analysed. In addition, an
analysis of the influence of the genetic variability of the metabolic enzymes CYP3A4 and
CYP3A5 on the concentrations of CsA and TAC was performed. The range of MPA interaction
with CsA and TAC in relation to the tested variants of the ABCG2 gene in kidney transplant
patients was also evaluated. The study included 68 patients (n=68, men=35, age 16-71) on
standard immunosuppresant protocols including MPA, CsA or TAc and glucocorticoids. Blood
samples were taken after completion of the initial week of treatement, at 8.00 a.m. before the
next dose for quantification of MPA, CsA or TAC trough concentrations followed by the
standard morning dose. During the 12-hour dosing interval for MPA, six blood samples were
taken to determine MPA concentration. Total plasma MPA was determined by HPLC method,
genotyping of polymorphisms UGT1A9 -2152C>T i -275 T>A, CYP3A4*22, CYP3A5*3,
ABCG2 c.421C>A, ABCC2 24 C>T i 1249 G>A, ABCB1 2677G>T/A, 3435C>T, 1236C>T,
SLCO1B1c.521T>C was performed by real-time polymerase chain reaction (qPCR).
Homozygous wild type patients and ABCG2 c.421C>A variant allele carriers were matched in
combined exacted and optimal full matching with respect to demographic, biopharmaceutic and
genetic variables. Variant allele effect was assessed by comparing the ratio of geometric means
(GMR) of dose adjusted steady state MPA pharmacokinetics estimates (frequentist and Bayes).
Results indicate significant association between ABCG2 c.421C>A variant allele and MPA
pharmacokinetics. In stable renal transplant recipients ABCG2 c.421C>A variant allele carriers
results showed an increased MPA bioavailability (AUCτ,ss ≈ 40 %) in accordance with
proportionally reduced clearance (CLT/F,ss ≈ 30 %) Additionally, significant role of the ABCG2
c.421C>A polymorphism in modulating the interaction of CsA and TAC with MPA was
observed. Results imply a significantly more pronounced effect of the ABCG2 c.421C>A
variant allele in patients on TAC therapy. Two times higer MPA bioavailability, lower
clearance and slower absorption rate were recorded compared to the patients on CsA therapy.
Results showed no influence of the tested polymorphisms of the metabolic enzyme UGT1A9
on MPA concentrations. Also, there was no overall effect of CYP3A4 and CYP3A5 enzyme
polymorphisms on CsA and TAC concentrations, possibly due to small number of patients
carrying variant alleles.

• Keywords: mikofenolna kiselina; ciklosporin; takrolimus; bolesnici s transplantiranim bubregom; ABCG2 polimorfizam
• Keywords (english): mycophenolic acid; cyclosporine; tacrolimus; transplant patients; ABCG2 polymorphism
• Language: croatian
• URN:NBN: urn:nbn:hr:163:870924
• Promotion: 2023
• Study programme: Title: Pharmacy and biochemistry; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor znanosti (doktor znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-01-31 12:57:00