Nada Starčević Čizmarević

Functional inference of methylenetetrahydrofolate reductase gene polymorphisms on enzyme stability as a potential risk factor for Down syndrome in Croatia.

Understanding the biochemical structure and function of the methylenetetrahydrofolate reductase gene (MTHFR) provides new evidence in elucidating the risk of having a child with Down syndrome (DS) in association with two common MTHFR polymorphisms, C677T and A1298C. The aim of this study was to evaluate the risk for DS according to the presence of MTHFR C677T and A1298C polymorphisms as well as the stability of the enzyme configuration. This study included mothers from Croatia with a liveborn DS child (n = 102) or DS pregnancy (n = 9) and mothers with a healthy child (n = 141). MTHFR C677T and A1298C polymorphisms were assessed by PCR-RFLP. Allele/genotype frequencies differences were determined using χ2 test. Odds ratio and the 95% confidence intervals were calculated to evaluate the effects of different alleles/genotypes. No statistically significant differences were found between the frequencies of allele/genotype or genotype combinations of the MTHFR C677T and A1298C polymorphisms in the case and the control groups. Additionally, the observed frequencies of the stable (677CC/1298AA, 677CC/1298AC, 677CC/1298CC) and unstable (677CT/1298AA, 677CT/1298AC, 677TT/1298AA) enzyme configurations were not significantly different. We found no evidence to support the possibility that MTHFR polymorphisms and the stability of the enzyme configurations were associated with risk of having a child with DS in Croatian population.

Interleukin 7 receptor alpha polymorphism rs6897932 and susceptibility to multiple sclerosis in the Western Balkans

The interleukin 7 receptor alpha single nucleotide polymorphism rs6897932 was identified as a multiple sclerosis susceptibility-modifying polymorphism in genome-wide and gene scan studies, mainly in populations in western countries. The aim of this study was to investigate the association of interleukin 7 receptor alpha rs6897932 with multiple sclerosis in populations from the Western Balkans: Serbia, Croatia, and Slovenia. A total of 678 unrelated white patients and 597 unrelated, ethnically matched healthy controls were included in the study. Genotyping was performed by real-time polymerase chain reaction. We found no significant difference in genotype or allele frequencies between controls and patients with multiple sclerosis either separately in Serbian, Croatian, and Slovenian populations or in the whole sample from the Western Balkans. The odds ratio for multiple sclerosis in this study was 1.04 (0.86—1.25) for the C allele. It is known that demographic as well as environmental factors have a substantial role in multiple sclerosis development, as well as population genetic background. The results of this study indicate that other types of genome variants should be required for the development and/or progression of multiple sclerosis, which may vary among populations.

The Role of TPA I/D and PAI-1 4G/5G Polymorphisms in Multiple Sclerosis

Background. Previous studies have shown impaired fibrinolysis in multiple sclerosis (MS) and implicated extracellular proteolytic enzymes as important factors in demyelinating neuroinflammatory disorders. Tissue-type plasminogen activator (t-PA) and its inhibitor (PAI-1) are key molecules in both fibrinolysis and extracellular proteolysis. In the present study, an association of the TPA Alu I/D and PAI-1 4G/5G polymorphisms with MS was analyzed within the Genomic Network for Multiple Sclerosis (GENoMS). Methods. The GENoMS includes four populations (Croatian, Slovenian, Serbian, and Bosnian and Herzegovinian) sharing the same geographic location and a similar ethnic background. A total of 885 patients and 656 ethnically matched healthy blood donors with no history of MS in their families were genotyped using PCR-RFLP. Results. TPA DD homozygosity was protective (OR = 0.79, 95% CI 0.63–0.99, P = 0.037) and PAI 5G5G was a risk factor for MS (OR = 1.30, 95% CI 1.01–1.66, P = 0.038). A significant effect of the genotype/carrier combination was detected in 5G5G/I carriers (OR = 1.39 95% CI 1.06–1.82, P = 0.017). Conclusions. We found a significantly harmful effect of the combination of the PAI-1 5G/5G genotype and TPA I allele on MS susceptibility, which indicates the importance of gene-gene interactions in complex diseases such as MS.

MMP-2 -1575G/A polymorphism modifies the onset of optic neuritis as a first presenting symptom in MS?

Previous studies show altered activities of matrix metalloproteinase (MMP)-2 and MMP-9 in serum and cerebrospinal fluid of multiple sclerosis (MS) and neuromyelitis optica (NMO) patients. Optic neuritis (ON) is a common symptom of both disorders. Here we investigated the impacts of MMP-2 -1575G/A and MMP-9 -1562 C/T gene polymorphisms on disease phenotype in 100 MS patients with ON as a first symptom and 376 MS patients with other initial symptomatology. The MMP-2 -1575G/A polymorphism led to a 5-year-earlier age of disease onset in MS patients with ON as a first symptom (p=0.009).

Angiotensin-converting enzyme gene polymorphism in patients with multiple sclerosis from Bosnia and Herzegovina.

BACKGROUND Increased activity of angiotensin-converting enzyme (ACE) in the blood and cerebrospinal fluid of patients with multiple sclerosis (MS), and the inhibition of ACE in experimental autoimmune encephalomyelitis, suggested that ACE may play a role in the pathogenesis and progression of MS. We recently published the first report on the potential association of MS and ACE I/D polymorphism in Slovenian and Croatian patients with MS, in which it was shown that the DD genotype might contribute to a higher risk of developing MS in men. To confirm these findings in a similar ethnic population, we analyzed ACE I/D gene polymorphism in patients with MS from Bosnia and Herzegovina. SUBJECTS AND METHODS One hundred and seventy patients with MS and 170 healthy controls were genotyped by the polymerase chain reaction method. RESULTS There was no significant difference in the distribution of ACE I/D genotypes (p=0.783) or in the allelic frequencies (p=0.538) between patients with MS and control subjects. When patients with MS were stratified by sex, no statistically significant differences in allele or genotype distributions were observed. Finally, there was no indication of an impact of the ACE I/D genotype on disease course or severity. CONCLUSION The ACE I/D polymorphism is not a risk factor for development of MS, nor does it contribute to disease severity in this Bosnia and Herzegovina population.

Association of circadian rhythm genes ARNTL/BMAL1 and CLOCK with multiple sclerosis

Prevalence of multiple sclerosis varies with geographic latitude. We hypothesized that this fact might be partially associated with the influence of latitude on circadian rhythm and consequently that genetic variability of key circadian rhythm regulators, ARNTL and CLOCK genes, might contribute to the risk for multiple sclerosis. Our aim was to analyse selected polymorphisms of ARNTL and CLOCK, and their association with multiple sclerosis. A total of 900 Caucasian patients and 1024 healthy controls were compared for genetic signature at 8 SNPs, 4 for each of both genes. We found a statistically significant difference in genotype (ARNTL rs3789327, P = 7.5·10−5; CLOCK rs6811520 P = 0.02) distributions in patients and controls. The ARNTL rs3789327 CC genotype was associated with higher risk for multiple sclerosis at an OR of 1.67 (95% CI 1.35–2.07, P = 0.0001) and the CLOCK rs6811520 genotype CC at an OR of 1.40 (95% CI 1.13–1.73, P = 0.002). The results of this study suggest that genetic variability in the ARNTL and CLOCK genes might be associated with risk for multiple sclerosis.

Chronic iron overload induces gender-dependent changes in iron homeostasis, lipid peroxidation and clinical course of experimental autoimmune encephalomyelitis

To analyze iron- and gender-dependent mechanisms possibly involved in pathogenesis of multiple sclerosis (MS) in this study we evaluated the effects of iron overload (IO) on iron status and lipid peroxidation processes (LPO) in tissues of female and male DA rats during chronic relapsing experimental autoimmune encephalomyelitis, a well-established MS animal model. Rats were treated by iron sucrose (75mg/kg bw/day) or with saline solution during two weeks before the sensitization with bovine brain homogenate in complete Freunds adjuvant. Clinical signs of EAE were monitored during 29 days. Serum and tissues of CNS and liver were sampled before immunization and at day 13th post immunization (during acute phase of EAE). The determination of ferritin, iron, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) and evaluation of histopathology were performed by ELISA, ICP spectrometry and immunohistochemistry. Results showed that IO in female EAE rats accelerated the onset of disease. In contrast, in male rats it accelerated the progression of disease and increased the mortality rate. During acute phase of EAE female IO rats sequestered more Fe in the liver, spinal cord and in the brain and produced more ferritin than male EAE rats. Male rats, however, reacted on IO by higher production of MDA or 4-HNE in the neural tissues and showed greater signs of plaque formation and gliosis in spinal cord. The data point to sexual dimorphism in mechanisms that regulate peripheral and brain iron homeostasis and imply that men and women during MS might be differentially vulnerable to exogenous iron overload.

Angiotensin-converting enzyme insertion/deletion gene polymorphism and interferon-β treatment response in multiple sclerosis patients: a preliminary report

We investigated the effect of the functional insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene on the response to interferon-&bgr; (IFN-&bgr;) therapy in Croatian and Slovenian patients with multiple sclerosis (MS). A total of 275 IFN-&bgr; treated MS patients [162 responders (Rs) and 113 nonresponders (NRs)] were genotyped by PCR. The ACE I/D genotype distribution and allele frequencies did not differ between female Rs and NRs. However, male NRs tended to have a greater prevalence of the DD genotype (P=0.073; odds ratio: 2.64; 95% confidence interval: 0.91–7.60) and a significantly higher frequency of the D allele (P=0.022; odds ratio: 2.43; 95% confidence interval: 1.13–5.20) than male Rs. Multiple forward stepwise regression analysis indicated that the negative response to IFN-&bgr; therapy was associated with the ACE-DD genotype in men (&bgr;=0.371; multiple R2 change: 0.132; P=0.009) and a higher pretreatment relapse rate in both men (&bgr;=−0.438; multiple R2 change: 0.135; P=0.015) and women (&bgr;=−0.208; multiple R2 change: 0.042; P=0.034). The ACE I/D polymorphism and pretreatment relapse rate accounted for ∼26.7% of the IFN-&bgr; response variability among the men in the sample. Further studies of a larger number of MS patients from different populations are necessary to evaluate these preliminary findings.

The lack of association between angiotensin-converting enzyme gene insertion/deletion polymorphism and nicotine dependence in multiple sclerosis

Blood‐borne angiotensin II is generated from angiotensinogen via cleavage by renin and angiotensin‐converting enzyme (ACE), an enzymatic cascade known as the renin–angiotensin system (RAS). Several lines of evidence indicate that ACE, beyond its classical role of mediating blood pressure regulation, might contribute to the etiology of substance addictions by influencing dopaminergic signaling. A functional insertion/deletion (I/D) polymorphism of the ACE gene was associated with risk for being a smoker among individuals with depression and with smoking severity in studies comprising patients with depression and healthy controls. Several reports have described significantly increased ACE activity in cerebrospinal fluid and serum among MS patients. Furthermore, in our previous work with MS patients from Croatian and Slovenian populations, we demonstrated that the ACE‐I/D polymorphism contributes to an elevated MS risk among male patients. Here we investigated whether the ACE‐I/D polymorphism might influence smoking behavior among patients with MS.

Geni i celijakija

Celijakija je bolest poremecenog imunosnog odgovora potaknutog glutenom koja se javlja u geneticki predisponiranih osoba. Svrha ovog rada je prikaza