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SHORT THESIS FOR THE DEGREE OF DOCTOR OF
PHYLOSOPHY (PhD)
ROLE OF HOMOCYSTEINE IN
ATHEROSCLEROTIC MANIFESTATIONS OF
NATIVE CORONARY ARTERIES AND VEIN
GRAFTS
Emília Balogh MD
Supe iso : Zsol Kőszegi MD, PhD
UNIVERSITY OF DEBRECENI
Kálmán Laki Doc o al School
Deb ecen, 2016
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By Emilia Balogh MD
Supe iso : Zsol Kőszegi MD, PhD
Doc o al School o Kálmán Laki, Uni e si y o Deb ecen
Head o he Examina ion Commi ee: Csongo Kiss, MD, PhD, DSc
Membe s o he Examina ion Commi ee: Noémi Nyolczas, MD, PhD
László Vi ág, MD, PhD, DSc
The Examina ion akes place
a he aining oom o Ins i u e o Pedia ics Dep . o Pedia ic Haema o-
Oncology, In e nal Medicine bldg. „B”., Clinical Cen e,
Uni e si y o Deb ecen on Sep embe 27, 2016, a 11 AM
Head o he De ense Commi ee: Csongo Kiss, MD, PhD, DSc
Re iewe s: And ás Komócsi, MD, PhD, DSc
Józse Szen miklósi, MD, PhD
Membe s o he De ense Commi ee: Noémi Nyolczas, MD, PhD
László Vi ág, MD, PhD, DSc
The PhD De ense akes place
a he Lec u e Hall o Bldg. „A”, Depa men o In e nal Medicine,
Facul y o Medicine, Uni e si y o Deb ecen
on Sep embe 27, 2016, a 1PM
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1. INTRODUCTION
My esea ch was ocused on he ole o homocys eine (Hcy) in
a he oscle o ic mani es a ions o na i e co ona y a e ies and enous
g a s.
The co ona y a e y disease (CAD) and i s se e e mani es a ions and
complica ions a e a majo cause o p ema u e mo ali y in de eloped
socie ies.
Degene a i e diseases o na i e co ona y a e ies
Co ona y scle osis is a se o p og essi e eac ions a ising om ch onic
inju ies o he endica dial su ace. The damaged endo helial a ea is
il a ed wi h oxidized lipop o eins and o ms a lipid- ich nec o ic co e
and a ib ous cap. The lesion is slowly calci ying, howe e he ma ginal
a eas emain pe manen ly in il ed by in lamma o y cells.
Degene a i e diseases o ein g a s
Excep om le an e io descending co ona y a e y, saphenous enous
g a s a e used widely o co ona y a e y bypass g a ing (CABG) due
o hei numbe and size a ie y and easy accessibili y o hei easie
p epa a ion. Bu hei long e m pa ency is se iously limi ed. A e en
yea s only 50-60% o he ein g a s emain unc ional. The ein g a
a he omas a e di e en om he na i e essels’ simila lesions: di use,
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ci cula , con ains less calci ica ion, ib in ha is hinne o absen , hey
a e p one o up u e and emboli o ma ion. Acco ding o expe imen al
models, ein g a s ha e di e en gene egula ion and gene exp ession
mechanisms and in lamma o y esponses caused by in lamma ion.
Physiology o homocys eine
Homocys eine (Hcy) is a sul u -con aining amino acids, an
in e media e p oduc o he p o ein me abolism. The Hcy connec s h ee
di e en pa hways o he amino acid me abolism: he ola e and he
me hionine cycle, which p o ides C1-pa icules o DNA-, RNA-, and
p o ein-, as well as glu a hione syn hesis. The plasma o al Hcy le el
di e s by age, sex and ace. In heal hy adul s is be ween 7-14 µmol/L.
Hype homocys einemia
Acco ding o ou esen knowledge only > 15µmol/L plasma Hcy has
pa hological ole and i is lis ed in o di e en ca hego ies o mild (15-
30 µmol/L), mode a e (30-100 µmol/L) and se e e (> 100 µmol/L)
hype homocys einemia (hHcy). The homocys eine me abolism is
in luenced by se e al exogenous and endogenous ac o s. Fo he
highes Hcy ele a ion is caused by he inhe i ed de iciency o
cys a hionine-be a-syn hase (CBS) enzyme ha is esponsible o
homocys eine-me ionin ans o ma ion. O he common causes o Hcy
le el ele a ion a e: nu i ion de iciency, lack o i amine B6-, i amin
B12-, and olic acid, inc eased in ake o me hionine, alcoholism,
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smoking, co ee consump ion, pe manen ly inac i e li es yle.
Homocys eine le el is also a ec ed by ce ain diseases, eg. diabe es,
cance (b eas -, o a y-, panc eas ca cinoma, acu e lymphoblas ic
leukemia), enal insu iciency, pso iasis, SLE, heuma oid a h i is,
hypo hy oidism, ce ain neu ological diseases (eg. demen ia),
medica ions: MTX, cyclospo ine, ime hop im, con acep i es, olic
acid, B6-, B12- an agonis s, an icon ulsan s, hiazide diu e ics, ni ogen
oxides, ib a es, me o min.
The „excess” o homocys eine o ms disul ide bonds, a ec s
h omboci e agg ega ion and adhesion, inc eases TXA2-, bu educes
p os acyclin le els and induces ascula in lamma ion. Changes
balance o endogenous ib inolysis by inc easing esis ance o ib ine
clo s agains o ib inolysis, inc ease isk o ascula h ombosis. The
hHcy acili a es o ma ion o o oxidized LDL, and choles e ol es e s
and hei depona ion in o endo helial lesions. Th oughou inco po a ing
in o p o eins Hcy gene a es an au oimmune esponse.
Hype homocys einemia and ca dio ascula disease, i amin
p e en ion ials
In he 1960s based on obse a ions o McCully on homocys eine was
cla i ied i s ela ionship wi h a he oscle osis and h omboembolism. In
1975 he has published wi h Wilson he "p o ein heo y" o
a he oscle osis (be ween homocys eine and a he oscle osis) and abou
i s i amin p e en ion. Clinical s udies pe o med since he middle o

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1990s ha e e i ied he independen isk ac o ole o hHcy in
ca dio ascula and a he o- h ombo ic diso de s, bu he combined
incidence o ca dio ascula disease ha was achie ed by combined
i amin he apy has se con adic o y esul s.
Mos o he andomized, con olled s udies ha e shown ha educ ion
o plasma Hcy le els by adminis a ion o i amin B6-, o B12- o olic
acid does no imp o e ou comes o ca dio ascula disease. The key o
unde s anding he homocys eine pa adox is cla i ying i s complex
biochemical ole.
2. OBJECTIVES
The ollowing objec i es we e se up:
1-2. Wha a e he ea u es o medium o long- e m mani es a ions o
na i e co ona y a he oscle osis and enous g a degene a ion
associa ed wi h homocys eine?
3-4. Is he e a ela ionship be ween homocys eine and o he isk
ac o s?
5. Is he e a possible a ole o homocys eine in es ima ion ela ed o
co ona y and ein g a disease p og ession in o de o imp o e he
e ec i i y o seconda y p e en ion?
3. METHODS
Design o s udy o na i e co ona ies
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A case-con ol s udy: compa ing CAD pa ien s wi h "nega i e" CAD
con ols based on co ona y angiog aphies. We examined isk ac o s
p o ile di e ecy beween pa ien and con ol g oups by collec ing da a
e ospe i ely om clinical da abase.
Ou aim was o in es iga e he CAD speci ic isk ac o s be ween
pa ien g oups by collec ing da a om clinical da abase. The con ol
g oup was o med by pa ien s who we e admi ed wi h suspec ed CAD,
bu co ona y lesions we e no con i med.
Design o s udy o enous g a s
Co ela ion e alua ion be ween isk ac o s and g a s a us among
pa ien s who unde wen CABG su ge y, and ecei ed a leas one
saphenous ein g a . The co ona y es s has been pe o med a leas
one yea a e hea su ge y, and was based on clinical indica ions.
The esea ch was ca ied ou be ween 2001-2013, in a single cen e , a
he Uni e si y o Deb ecen Dep . O Ca diology in ha mony wi h he
Decla a ion o Helsinki and au ho i y egula ions. The esea ch has
been no i ied o he Ins i u ional E hics Commission. The in ol ed
pa ien s ecei ed p io o al and w i en in o ma ion abou he possibili y
o p ocessing da a o esea ch. They all ga e hei w i en consen ,
which was a chi ed oge he wi h hei clinical documen a ion.
Da a was collec ed om elec onic da abase (MedSolu ion) o he
Ins i u e o Ca diology Clinical Cen e Uni e si y o Deb ecen. Da a o
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pe sonal iden i ica ion (name, da e o bi h, social secu i y numbe ),
was masked h oughou he s a is ical analysis. The physical
examina ion and collec ion o da a o all pa ien s was pe o med by
me.
Selec ion o pa ien s wi h na i e co ona ies
A 1010 pa ien s we e included among hose admi ed o DE KK
Ins i u e o Ca diology du ing 2001-2002 wi h suspec ed CAD,
pe o med a selec i e co ona y angiog am.
Selec ion o pa ien s wi h ein g a s
The s udy included 237 ( wo hund ed hi y-se en) pa ien s who we e
admi ed o DE KK Ins i u e o Ca diology du ing 2001-2002, ollowed
by CABG wi h a leas one saphenous ein g a .
Reco ded da a
Fo he pa ien s included he ollowing da a we e eco ded: amily
his o y o a he oscle osis/complica ions, p e ious myoca dial
in a c ion, hype lipidemia, smoking his o y and habi s, high blood
p essu e, diabe es, ca o id s enosis, pe iphe al a e ial ascula disease,
women's ho monal s a us. The ollowing demog aphic in o ma ion was
eco ded: age (yea s), sex, body weigh (kg), heigh (me e s), body
mass index, i al signs, and le en icula ejec ion ac ion, ca diac
unc ion.
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Co ona y and ein g a s a us cla i ica ion
Selec i e angiog aphy examina ions and hei assessmen we e ca ied
by expe ienced ca diologis s. The s anda d es me hodology was done
h oughou igh emo al a e y app oach by Judkins echnic. The
s anda d iews consis ed o a leas 3 sho s o he le co ona y
a e y/g a b anches and o wo s anda d iew shoo ing 12.5 ames/
sec speed om he igh co ona y b anches by Philips In eg is ype o
x- ay machine (In u is Viewe Li e Sui e 1.0, Philips, The
Ne he lands). Assessmen o co ona y a e y lumen diame e na owing
consis ed o de e mina ing localisa ion and deg ee o s enoses (%). The
numbe o g a s, hei localiza ion and g a in e en ions ha e been
documen ed.
Co ona y angiog aphies pe o med wi hin a yea a e CABG ha e
been excluded om e alua ion – o sepa a e cases due o echnical e o
o p ema u e g a h ombosis.
The diagnosis o SVG disease was based on independen judgemen o
epea co ona y angiog aphies by 2 expe ca diologis s; SVGs we e
classi ied acco ding o hei “lumen s a us” (diame e s enosis; [%]) a
epea co ona y angiog aphy as “in ac ” wi h a <20% lumen diame e
educ ion, “na owed” wi h a lumen diame e s enosis be ween 20-
99%, and “occluded” (closed lumen). Pa ien s ha ing >1 SVG wi h
di e en g a s a us a ollow up we e anked acco ding o he mo e
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8. PUBLICATIONS

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THANKS GIVING
I would like o exp ess my hanks o all hose who helped me pe o m
his scien i ic esea ch, as well as in he p epa a ion o his PhD hesis:
p o esso D . Is án Édes, p o esso D . Is án Czu iga, p o esso D .
László Muszbek, D . Zsuzsanna Be eczky, D . É a Ka ona, D . László
Balkay, E zsébe Ráczné Csiha, Gábo Ká olyi, Balázs Nyul.
I would like o hank o all my p e ious colleauges a he Ca diology
Ins i u e, o me Hea and Lung Clinic, Hea Su ge y Depa men ,
Hemodynamic Labo a o y, Clinical Labo a o y Ins i u e, Clinical
Labo a o y Resea ch Depa men .
I would like o hank he suppo o my u o , D . Zsol Kőszegi and
inally, wi h deep g a i ude and lo e I hink o my pa en s and my
amily: Wi hou hei suppo I could no each my goals.