Processes of plasma protein N-homocysteinylation in multiple sclerosis.
BACKGROUND
Homocysteine thiolactone (HTL) is a cyclic thioester of homocysteine (Hcy) contributing to the toxicity of this amino acid. HTL spontaneously reacts with protein lysine residues leading to altered properties of target proteins and induction of immune response. HTL is hydrolyzed to Hcy by plasma enzyme, paraoxonase 1 (PON1). Although both Hcy and PON1 may be involved in the pathogenesis of multiple sclerosis (MS), protein modification by HTL in this disease has not been studied so far. Purpose/Aim: The aim of this study was to assess the level of Hcy, HTL and autoantibodies against N-homocysteinylated proteins as well as PON1 activity in patients with MS.


METHODS
The studies were performed in 61 MS patients with relapsing-remitting (RR group, n = 25) and secondary-progressive type of MS (SP group, n = 36), and in healthy people (C - control group, n = 44).


RESULTS
Homocysteine level was significantly higher in MS patients comparing to control group (C vs. RR p < 0.01; C vs. SP p < 0.05). The level of HTL tended to be higher in RR-MS in comparison to control group, but it did not reach the level of significance. The level of antibodies against N-homocysteinylated proteins did not differ significantly between studied groups. PON1 activity was significantly lower in SP type of MS (SP vs. C p < 0.05; SP vs. RR p < 0.05).


CONCLUSIONS
Although plasma Hcy concentration is higher in MS patients and PON1 activity is reduced in the SP form, MS is associated with minor or no changes in protein-attached HTL and anti-homocysteinylated protein immune response.
a Department of Neurology , Lublin Medical University , Lublin , Poland.
A
A
Jamroz-Wiśniewska
b Department of Pathophysiology , Lublin Medical University , Lublin , Poland.
J
J
Bełtowski
c Department of Neurology , University of Rzeszów , Rzeszów , Poland.
H
H
Bartosik-Psujek
b Department of Pathophysiology , Lublin Medical University , Lublin , Poland.
G
G
Wójcicka
a Department of Neurology , Lublin Medical University , Lublin , Poland.
K
K
Rejdak
D000328:Adult; D043303:Aryldialkylphosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism; D005260:Female; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000097:blood* / Q000175:diagnosis; D012709:Serum Albumin
D015415:Biomarkers; D001798:Blood Proteins; C502359:N-homocysteinylated albumin; D012709:Serum Albumin; D006710:Homocysteine; C007957:homocysteine thiolactone; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human
antibodies against N-homocysteinylated proteins; homocysteine; homocysteine thiolactone; hyperhomocysteinemia; multiple sclerosis; oxidative stress; paraoxonase