| Abstract | Uvod i cilj istraživanja
Akutni koronarni sindrom bolest je koja nastaje destabilizacijom i rupturom
aterosklerotskog plaka epikardijalne koronarne arterije u čemu glavnu ulogu igraju mehanizmi
koji utječu na staničnu signalizaciju i proizvodnju čimbenika promocije upale. Glavnina
stanične komunikacije zbiva se na membrani čija je površina pokrivena oligosaharidnim
strukturama koje su vezane za membranske proteine i lipide u obliku glikoproteina i
glikolipida. Glikozilacija je jedina modifikacija proteina i lipida koja može rezultirati
značajnim strukturalnim promjenama proteina, a zna se da ima važnu ulogu u integraciji
različitih funkcija u višim organizmima. Cilj istraživanja bio je odrediti gensku ekspresiju
glikoziltransferaza u bolesnika s akutnim koronarnim sindromom i usporediti je s kontrolnom
skupinom kod koje je isključena koronarna bolest. ----- Ispitanici i metode
U istraživanje je uključeno 52 bolesnika s akutnim koronarnim sindromom i 32
ispitanika u kontrolnoj skupini. Bolesnicima su izmjerene genske ekspresije 8
fukoziltransferaza i 10 sijaliltransferaza u dva navrata: u akutnoj fazi unutar 24 sata od
početka bolesti i u kroničnoj fazi prosječno 8 dana nakon početka bolesti. Nakon obrnutog
prepisivanja RNA u DNA, PCR u stvarnom vremenu učinjena je prema SYBR Green
protokolu, a za analizu relativne ekspresije kao referentni geni korišteni su β-actin i GAPDH.
Za statističku analizu upotrijebljen je Mann-Whitney test, Wilxocon signed rank test,
Spearmanov test korelacije i chi kvadrat test. Razina značajnosti P podešena je na 0.05. ----- Rezultati
Nađena je značajno niža relativna ekspresija FUT 4 u bolesnika s akutnim koronarnim
sindromom u odnosu na oba referentna gena (P<0,001 za GAPDH i P<0,05 za beta aktin). Ta
značajna razlika očitovala se i u drugom uzorkovanju u bolesnika. Nije bilo značajnih razlika
u ekspresiji FUT 7 između bolesnika u akutnoj fazi i kontrola. Međutim zbog gotovo 50%
sniženja ekspresije FUT 7 u bolesnika u drugom uzorkovanju ta je ekspresija bila značajno niža u bolesnika u kroničnoj fazi u usporedbi s kontrolnom skupinom (P<0,001 za oba
referentna gena). Taj učinak je pripisan terapiji statinima, s obzirom da je nađena značajno
niža ekpresija FUT 7 u osoba koje su uzimale statine neovisno o prisutnosti akutnog
koronarnog sindroma. Ekspresije ST6Gal1, GM3 sintaze i ST6GalNac 4 bile su značajno niže
u bolesnika u oba vremena uzorkovanja i to za oba referentna gena (P<0,05, P<0,001 i
P<0,05, tim redom). Nađena je značajno niža ekspresija ST6GalNac3 u bolesnika u drugom
uzorkovanju, što je također pripisano značajno većoj zastupljenosti terapije statinima među
bolesnicima. ----- Zaključak
Nađene su značajne razlike u genskoj ekspresiji glikoziltransferaza zaduženih za
sintezu lektina, sijaliziranog antigena Lewis X i gangliozida, te sijalizaciju integrina. Sve te
strukture imaju dokazano važnu ulogu u začetku, poticanju i kontroli upalne reakcije koja je
prema dosadašnjim istraživanjima temelj za razvoj i progresiju ateroskleroze, te su zanimljiv
predmet budućih istraživanja. |
| Abstract (english) | Background and aim
Acute coronary syndrome (ACS) is caused by destabilization and rupture of
atherosclerotic plaque in the epicardial coronary artery. Mechanisms that affect cell signaling
and production of factors promoting inflammation play the main role in that process. The
majority of cellular communication takes place on the membrane whose surface is covered
with oligosaccharide structures that are related to membrane proteins and lipids in the form of
glycoproteins and glycolipids. Glycosylation is the only modification of proteins and lipid
which can result in significant structural changes in the protein, and it is known to play an
important role in the integration of different functions in higher organisms. The aim of this
study was to determine the genetic expression of glycosyltransferases in patients with acute
coronary syndrome and compare it with a control group of subjects that are proven to be
coronary disease free. ----- Subjects and Methods
The study included 52 patients with acute coronary syndrome and 32 subjects in the
control group. Glycosyltransferases genetic expression was measured in patients with ACS on
two occasions: in the acute phase within 24 hours of acute onset of chest pain, and in chronic
phase (average of 8 days after onset of illness). After reverse transcription of RNA into DNA,
real-time PCR was performed by SYBR Green protocol, and relative expression was
measured. Reference genes used for relative expression measurement were β-actin and
GAPDH. Statistical analysis was done using Mann-Whitney test, Wilxocon signed rank test,
Spearman correlation test and chi square test. The level of significance was set to P<0.05. ----- Results
There was a significantly lower relative expression of FUT 4 in patients with ACS in
relation to both reference genes (P <0.001 for GAPDH and P <0.05 for beta-actin). This
significant difference was also reflected in the second sampling in patients with ACS. There
was no significant difference in FUT 7 expression between two groups in the acute phase.
However, due to an almost 50% reduction in the expression of FUT 7 in patients with ACS in
the second sampling, FUT7 expression in the second sampling was significantly lower when
compared with the control group (P <0.001 for both reference genes). This effect was
attributed to statin therapy, as significant downregulation of FUT 7 was found in subjects
taking statins irrespective of the presence of acute coronary syndrome. ST6Gal1, GM3
synthase and ST6GalNac 4 were significantly downregulated in patients with ACS in both
stages of disease (P <0.05, P <0.001 and P <0.05, respectively). There was a significantly
lower expression ST6GalNac3 in ACS patients in the second sampling, which was also
attributed to a significantly higher prevalence of statin therapy. ----- Conclusion
There were significant differences in gene expression of glycosyltransferases
responsible for the synthesis of lectins, syalizated Lewis X antigen, and ganglioside and for
integrins syalization. All these structures play an important role in the promotion and control
of inflammatory response, which is important in the development and progression of
atherosclerosis. More basic and clinical studies on glycosyltransferases and glycosilation in
the pathophysiology of the ACS are mandatory. |
