| Abstract | Cilj: Osnovni cilj ovog istraživanja bio je utvrditi jesu li polimorfizmi gena DNA metiltransferaza (DNMT) i DNA metilacija dugih raspršenih nukleotidnih elemenata 1 (LINE-1) majke te pridruženi čimbenici (starosna dob majke, uživanje duhanskog dima, indeks tjelesne mase), samostalno ili u kombinaciji, čimbenici predispozicije za idiopatski spontani prijevremeni porod (ISPP).
Ispitanici i metode: Istraživanje je osmišljeno kao istraživanje parova. Ispitivanu skupinu pacijentica činile su 162 majke s ISPP-om, a kontrolnu skupinu 162 majke s terminskim porodom. Za genotipizaciju DNMT1 rs2228611, DNMT3A rs1550117, DNMT3B rs1569686, DNMT3B rs2424913 i DNMT3L rs2070565 polimorfizama korištena je metoda lančane reakcije polimerazom i polimorfizma duljine restrikcijskih fragmenata. Kvantifikacija LINE-1 DNA metilacije određena je MethyLight metodom.
Rezultati: Između ispitivane i kontrolne skupine pronađena je statistički značajna razlika u raspodjeli učestalosti kombinacija genotipova AA+GG/CC DNMT1 rs2228611 i DNMT3B rs1569686/rs2424913 (P<0,05). U pacijentica s obiteljskim PP-om, u usporedbi s pacijenticama s ne-obiteljskim PP-om, utvrđena je statički značajno veća učestalost T alela u DNMT3B rs1569686 i rs2424913 (P=0,002; P˂0,001), doprinoseći 3,30 i 3,54 puta većem izgledu za obiteljski PP prema dominantnim genetičkim modelima (P=0,003; P=0,002). DNMT3B rs1569686 i rs2424913 T aleli su pokazali statistički značajno veću učestalost u pacijentica s ISPP-om koje su uživale duhanski dim prije trudnoće (P=0,001; P=0,021). Vrijednosti LINE-1 DNA metilacije u skupini pacijentica s vrlo ranim PP-om bile su statistički značajno niže u odnosu na pacijentice s ekstremno ranim (P=0,035) i ranim PP-om (P=0,036). Stupnjevitom regresijskom analizom utvrđeno je da se 13,1% promjena vrijednosti LINE-1 DNA metilacije može objasniti anamnezom opterećenom prethodnim PP-om (P=0,011), a 8,4% vaginalnim krvarenjem u trudnoći (P=0,033). T alel (TT+TG/TC genotipovi) DNMT3B rs1569686 i rs2424913 polimorfizma predisponiraju LINE-1 DNA hipometilaciju (P=0,021; P=0,056).
Zaključak: DNMT3B rs1569686 i rs2424913 polimorfizmi predstavljaju čimbenike predispozicije za ISPP u žena s pozitivnom obiteljskom anamnezom na PP, dok LINE-1 DNA hipometilacija predstavlja čimbenik predispozicije za ISPP u žena s pozitivnom osobnom anamnezom na PP i vaginalnim krvarenjem u prvom tromjesečju trudnoće |
| Abstract (english) | Objectives: The main objective of this study was to determine whether maternal single nucleotide polymorphisms of the DNA methyltransferase genes (DNMT), long interspersed nucleotide elements 1 (LINE-1) DNA methylation and associated factors (maternal age, smoking, body mass index), are the risk factors for idiopathic spontaneous preterm birth (ISPTB).
Patients and methods: This case-control study included two groups of cases: group of patients with ISPTB and control group. A total of 162 mothers comprised the group of patients with ISPTB. The control group included 162 mothers with term birth. Genotyping of DNMT1 rs2228611, DNMT3A rs1550117, DNMT3B rs1569686, DNMT3B rs2424913 and DNMT3L rs2070565 polymorphisms was performed using the combination of polymerase chain reaction and restriction fragment length polymorphism methods. Quantification of LINE-1 DNA methylation was determined using MethyLight method.
Results: We found a statistically significant difference in the distribution of combination of genotypes AA+GG/CC DNMT1 rs2228611 and DNMT3B rs1569686/rs2424913 between women with ISPTB and control group of pregnant women (P<0.05). The DNMT3B rs1569686 and rs2424913 T alleles were significantly more frequent in women with familial PTB than non-familial PTB (P=0.002; P˂0.001), and contributed to a 3.30 and 3.54 increased odds for familial PTB under dominant genetic models (P=0.003; P=0.002). Furthermore, the DNMT3B rs1569686 and rs2424913 T alleles were significantly more frequent in women with ISPTB who smoked before pregnancy (P=0.001; P=0.021). Values of LINE-1 DNA methylation in patients with very early ISPTB were significantly lower compared to patients with extreme (P=0.035), and moderate ISPTB (P=0.036). Stepwise regression analysis showed that values of LINE-1 DNA methylation were significantly influenced by previous PTB (R2=13.1%; P=0.011) and vaginal bleeding (R2=8.4%; P=0.033). The DNMT3B rs1569686/rs2424913 T alelle (TT+TG/TC genotypes) has a significant impact on LINE-1 DNA methylation (P=0.021; P=0.056).
Conclusion: DNMT3B rs1569686 and rs2424913 polymorphisms could be factors of predisposition to ISPTB in women with familial preterm birth, while LINE-1 DNA hypomethylation could be a factor of predisposition to ISPTB in women with previous preterm birth and vaginal bleeding in first trimester of pregnancy. |
