Statement of problem: We have shown that the C677T 5,10 methylenetetrahydrofolate reductase (MTHFR) variant is associated with elevated maternal serum α-fetoprotein (MSAFP), the most common screening test for neural tube defects (NTD). Therefore, past contradictory studies of NTDs and C677T MTHFR may have been biased because of changes in case populations after prenatal diagnosis and termination of pregnancy. Further, an unexplained elevation of MSAFP is known to increase the risk for later pregnancy complications. Is the C677T MTHFR variant a predisposing genetic variant for both NTDs and later complications of pregnancy? Methods: A retrospective study of women with pregnancies resulting in NTD outcome and women with unexplained elevations of MSAFP was undertaken. Women and their partners were genotyped for the C677T MTHFR allele. Couples with a pregnancy resulting in a NTD outcome were compared to couples whose pregnancy outcome did not involve. Couples with unexplained elevations of MSAFP who did and did not have later complications of pregnancy were also compared. Allele frequencies for all groups were then compared against the previously established Manitoba population allele frequency (based on 977 consecutive newborn metabolic screening bloodspots). A review of all studies of NTDs and association with the C677T MTHFR variant was undertaken to determine if the association between the variant and MSAFP is a source of bias. NTD incidence was examined before and after folic acid food fortification introduced in Canada in 1999. Results: There is an increase in the allele frequency of the C677T MTHFR variant in parents with an unexplained elevated MSAFP followed by later complications of pregnancy. The C677T MTHFR variant is also a contributing genetic factor to NTDs worldwide. The incidence of NTDs in Manitoba has decreased by 37% since food fortification with folic acid was introduced. Conclusions: The C677T MTHFR variant is a contributing genetic factor to both later complications of pregnancy after an unexplained elevation of MSAFP and to NTDs. This variant is folate sensitive and folic acid fortification has reduced the incidence of NTDs.

Various hormones have been studied as regards prediction of pregnancy outcome after infertility treatment, but no ideal candidate has been found. Folate and genetic variations in folate metabolism have also been associated with infertility, but it remains unclear how these factors affect IVF pregnancy outcome. It is known that infertility is associated with active folic acid supplement use, but the effect of socioeconomic and lifestyle factors on folic acid supplement use in infertile women has not been well investigated. The overall aim of this work was to obtain information on the prediction of live birth, and to study factors affecting the role of folate and folic acid intake in relation to IVF pregnancy outcome. Infertile women with various infertility diagnoses were studied. Healthy, fertile non-pregnant women were used as controls in three of the studies. Blood samples were taken for assay of eight different hormones, folate and homocysteine, and for genomic DNA extraction. A questionnaire was used to assess background data and use of folic acid supplements. Twenty-four-hour recall interviews were performed for validation of the questionnaire. The studied hormones were not good predictors of live birth. The best predictor was age of the women, together with ovulatory menstrual cycles, and thyroid-stimulating hormone and anti-Müllerian hormone (AMH) status. Well-educated women, high-status employed women, and married and infertile women used the most folic acid supplements. Infertile women had better folate status than fertile women. However, pregnancy outcome after infertility treatment was not dependent on folic acid intake, folate status, genetic variation of 5,10-methylenetetrahydrofolate reductase or socioeconomic status. In conclusion, AMH levels vary less than those of other hormones during the menstrual cycle, and AMH could be used as a predictive marker of live birth together with age and ovulation. Folate might play a minor role in IVF pregnancy outcome, but the importance of folate as regards other health perspectives should not be forgotten.

Statement of problem: We have shown that the C677T 5,10 methylenetetrahydrofolate reductase (MTHFR) variant is associated with elevated maternal serum α-fetoprotein (MSAFP), the most common screening test for neural tube defects (NTD). Therefore, past contradictory studies of NTDs and C677T MTHFR may have been biased because of changes in case populations after prenatal diagnosis and termination of pregnancy. Further, an unexplained elevation of MSAFP is known to increase the risk for later pregnancy complications. Is the C677T MTHFR variant a predisposing genetic variant for both NTDs and later complications of pregnancy? Methods: A retrospective study of women with pregnancies resulting in NTD outcome and women with unexplained elevations of MSAFP was undertaken. Women and their partners were genotyped for the C677T MTHFR allele. Couples with a pregnancy resulting in a NTD outcome were compared to couples whose pregnancy outcome did not involve. Couples with unexplained elevations of MSAFP who did and did not have later complications of pregnancy were also compared. Allele frequencies for all groups were then compared against the previously established Manitoba population allele frequency (based on 977 consecutive newborn metabolic screening bloodspots). A review of all studies of NTDs and association with the C677T MTHFR variant was undertaken to determine if the association between the variant and MSAFP is a source of bias. NTD incidence was examined before and after folic acid food fortification introduced in Canada in 1999. Results: There is an increase in the allele frequency of the C677T MTHFR variant in parents with an unexplained elevated MSAFP followed by later complications of pregnancy. The C677T MTHFR variant is also a contributing genetic factor to NTDs worldwide. The incidence of NTDs in Manitoba has decreased by 37% since food fortification with folic acid was introduced. Conclusions: The C677T MTHFR variant is a contributing genetic factor to both later complications of pregnancy after an unexplained elevation of MSAFP and to NTDs. This variant is folate sensitive and folic acid fortification has reduced the incidence of NTDs.

We used the GENECONV program, the Hsu et al. (2010) method and phylogenetic analyses to analyze the gene conversions which occurred in the growth hormone, folate receptor and trypsin gene families of six primate species. Significant positive correlations were found between sequence similarity and conversion length in all but the trypsin gene family. Converted regions, when compared to non-converted ones, also displayed a significantly higher GC-content in the growth hormone and folate receptor gene families. Finally, all detected gene conversions were found to be less frequent in conserved gene regions and towards functionally important genes. This suggests that purifying selection is eliminating all gene conversions having a negative functional impact.

Significant progress has been made in the development of new agents against cancer and new ways of delivering existing and new agents. Yet, the major challenge to target and selectively kill cancer cells while affecting as few healthy cells as possible remains. When linked with tumor targeting moieties such as tumor-specific ligands or monoclonal antibodies, nanoparticles can be used to target cancer-specific receptors, tumor biomarkers as well as tumor vasculatures with high affinity and precision. Recently, the use of nanoparticles for drug delivery and targeting has emerged as one of the most exciting and clinically important areas in cancer nanotechnology. In this work, we tested the hypothesis that our novel ternary biomolecular nanostructures of folic acid (FA), biodegradable polymer, and paclitaxel will improve the delivery and tumor-specific distribution of the anticancer drug. The design was based on three principles: 1) Passive targeting via enhanced permeation and retention (EPR) effect; 2) active targeting via a tumor-specific ligand; and 3) prodrug that would release the drug upon delivery. First, self-assembled polymer-paclitaxel-FA nanostructures were synthesized. Their physicochemical properties were examined and biological efficacy was tested. The conjugates had significantly improved solubility in water, enabling cremophor-free formulation. Second, in vitro cellular toxicity and targeting ability of the nanostructures were investigated. In cancer cell lines with high folate receptor (FR) expression, the ternary conjugates were efficiently taken up whereas no detectable association was found in cells with minimal or no FR expression. Third, in vivo investigation in human xenograft mice models was carried out. Ternary nanostructures drastically inhibited tumor growth without inducing systemic toxicity or side effects. The ternary nanostructures displayed remarkable anti-angiogenic effect on tumor vasculature. Heparin-paclitaxel-FA was also very effective in drug resistant tumors, potentially overcoming multidrug resistance. Studies in other cancer models are in progress to determine the spectrum of applicability of these ternary nanostructures. The design principles applied in these nanoparticles can be extended to delivery and targeting of diagnostic and imaging agents. The ability to engineer multifunctional nanostructures will have a significant impact on cancer diagnostics, molecular profiling, and the integration of cancer therapy and imaging.

Pregnancy complications associated with placental development affect approximately one third of all human pregnancies. Genome health is essential for placental and fetal development, as DNA damage can lead to pregnancy loss and developmental defects. During this developmental phase rapid DNA replication provides an increased opportunity for genome and epigenome damage to occur[1]. Maternal nutrition is one of the principal environmental factors supporting the high rate of cell proliferation and differentiation. Folate functions in one-carbon metabolism and regulates DNA synthesis, DNA repair and gene expression[1]. Deficiencies or defects in gene-nutrient interactions associated with one-carbon metabolism can lead to inhibition of cell division, cell cycle delay and an excessive apoptotic or necrotic cell death rate [2], which may affect placentation. This study is the first to investigate the association between genomic damage biomarkers in late pregnancy complications associated with uteroplacental insufficiency (UPI) including preeclampsia and intrauterine growth restriction (IUGR). The results indicate that genome damage in the form of micronucleated cells in peripheral blood lymphocytes at 20 weeks gestation is significantly increased in women at risk of developing an adverse pregnancy outcome. The observed OR for the high micronuclei frequency may be the highest observed for any biomarker selected in relation to risk of pregnancy complications to date (15.6 – 33.0). In addition, reduced apoptosis was observed in association with increased micronuclei, suggesting that the cells may have escaped specific cell-cycle checkpoints allowing a cell with DNA damage to proceed through mitosis. This study demonstrated that an increase in plasma homocysteine concentration at 20 weeks gestation is associated prospectively with the subsequent development of UPI, indicating a causal relationship. The MTR 2756 GG genotype was significantly associated with increased plasma homocysteine concentration and UPI. Furthermore, the MTHFD1 1958 single nucleotide polymorphism was associated with increased risk for IUGR. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1309296 / Thesis (Ph.D.) -- School of Paediatrics and Reproductive Health, 2007

Zugl.: Mainz, Univ., Diss., 2004 / Hergestellt on demand

DNA methylation is an epigenetic mechanism that regulates the gene transcription. Folate is used in cellular synthesis of methyl groups, nucleic acids and amino acids. In complex diseases like cancer and neural tube defects (NTD), various genetic and epigenetic alterations can be found that disrupt the normal cell function. The main goals of this thesis were to analyze whether the genes responsible for the folate transport (FOLR1, PCFT, and RFC1) could be regulated by DNA methylation in placenta, blood leukocytes and colorectal cancer. We also addressed the genome-wide DNA methylation changes in colorectal cancer andcervical cancer.We found that changes in the methylated fraction of the RFC1 gene were dependent on the RFC1 80G>A polymorphism in placental specimens with NTDs and blood leukocytes from subjects with high homocysteine (Paper I). In colorectal cancer, the greatest difference in DNA methylation was observed in the RFC1 gene and was related to a lower protein expression (Paper II).In Paper III and IV we studied the DNA methylated fraction using a high-density array. Paper III was focused on genes in the DNA repair pathway and frequently mutated in colorectal cancer. We found that aberrant methylation in the DNA mismatch repair genes was not a frequent event in colorectal cancer and we identified five candidate biomarker genes in colorectal cancer, among them the GPC6 and DCLRE1C genes. In Paper IV, we found hypomethylation of genes involved in the immune system in cervical cancer specimens compared to healthy cervical scrapes and we identified twenty four candidate genes for further evaluation ofclinical value.In conclusion, the work of this thesis filled a relevant knowledge gap regarding the role of differential methylation of the folate transport genes in NTD and colorectal cancer. This thesis work also provided insights into the functional role of DNA methylation in cancer specific pathways and identified potential novel biomarker genes.

Introdução: Dispepsia funcional é uma doença que possui critérios diagnósticos definidos por reuniões de consenso, conhecidos por critérios de Roma. Apresenta alta prevalência mundial, grande impacto social e redução na qualidade de vida do indivíduo. Helicobacter pylori está envolvida na patogênese da dispepsia funcional, sendo indicada sua detecção e erradicação no tratamento dos pacientes dispépticos funcionais. H. pylori também tem sido sugerida como um importante agente na etiologia de níveis baixos de Vitamina B12 no soro. A hiperhomocisteinemia secundária à deficiência de Vitamina B12 e folato podem constituir um risco para as doenças cardiovasculares. Objetivo: investigar a relação entre os níveis séricos de Vitamina B12, folato e homocisteína e infecção pelo H. pylori em pacientes dispépticos funcionais. Métodos: Foram incluídos pacientes dispépticos funcionais, pelos critérios de Roma III do estudo HEROES (Helicobacter Eradication Relief of Dyspeptic Symptoms) - ClinicalTrials.gov número NCT00404534. Os pacientes dispépticos que apresentaram positividade para H. pylori foram randomizados para erradicação da bactéria com antibiticoterapia oral ou placebo. Após doze meses realizaram o segundo exame endoscópico com mesma metodologia. Da amostra total, 77 continuaram positivos para a infecação por H. pylori e 77 tiveram como resultado a erradicação da bactéria H. pylori, ou seja, negativaram. O material biológico foi previamente coletado e armazenado, além dos respectivos dados demográficos e clínicos. As amostras foram armazenadas a -80◦C em ependorf e realizadas medidas em soro dos níveis de vitamina B12 e folato e homocisteína. Resultados: Da amostra total, 77 pacientes eram H. pylori positivo (15 homens e 62 mulheres) e 77 eram H.pylori erradicados (21 homens e 56 mulheres). A média de idade foi de 47,8±11,5, em relação à idade e gênero não houve diferença significativa entre os grupos (p > 0,05). Quanto aos resultados reunidos em categorias (níveis de vitamina B12, folato e homocisteína), conforme os pontos de corte usados na literatura, não foi observada diferença estatisticamente significativa entre os dois grupos de pacientes (p > 0,6). Não houve correlação entre idade e níveis de vitamina B12 (p = 0,924). Houve diferença entre gêneros para homocisteína (p = 0,035), porém não houve significância para vitamina B12 (p = 0,584) e folato (p = 0,312). Não houve diferença entre níveis de homocisteína de pacientes H. pylori positivos e H. pylori erradicados para ambos os gêneros (p > 0,5). Conclusões: O presente estudo demonstrou que não houve relação significativa entre os níveis séricos de Vitamina B12, folato e homocisteína e infecção por H. pylori em relação aos H. pylori erradicados nos dispépticos funcionais. E quanto aos níveis de homocisteína comparados entre gêneros, os valores foram mais altos em homens. / Introduction: Functional dyspepsia a disease which has diagnosis criteria defined by consensus gatherings, known as the Rome criteria. It is highly prevalent worldwide, has great social impact, and reduces the quality of life of individuals. Helicobacter pylori is involved in the pathogenesis of functional dyspepsia, and its detection and eradication are indicated in the treatment of functional dyspepsia patients. H. pylori has also been suggested as an important agent in the etiology of low levels of vitamin B12 in serum. A hyperhomocysteinemia secondary to vitamin B12 and folate deficiencies could pose a risk for cardiovascular diseases. Objective: To investigate the relationship among the serum levels of Vitamin B12, folate and homocysteine, and the H. pylori infection in functional dyspeptic patients. Methodology: A group of patients with functional dyspepsia was included, following the Rome III criteria from the study HEROES (Helicobacter Eradication Relief of Dyspeptic Symptoms) – ClinicalTrials.gov number NCT00404534. The dyspeptic patients who were positive for H. pylori in tissue biopsy were randomized to eradication of the bacteria with oral antibiotic therapy or placebo. After twelve months, a second endoscopy was performed with the same methodology. Of the total sample, 77 patients remained positive for H. pylori and 77 patients had as a result the eradication of H. pylori bacteria, that is, they became negative. The biological material was previously collected and stored, besides its demographic and clinical data. The samples were stored at -80◦C in Eppendorf, they were measured in the serum of vitamin B12 folate and homocysteine levels. Results: Of the total sample, 77 patients were positive for H. pylori (15 men, 62 women) and 77 patients had the eradication of H. pylori (21 men, 56 women). The average age of the sample was about 47,8±11,5,regarding age and gender, it was not observed significant difference between the groups (p > 0,05). Concerning the results gathered into categories (the levels of vitamin B12, folate, and homocysteine), as the cut off points used in the literature, it was not observed statistically significant difference between the two groups of patients (p > 0,6). There was no correlation between age and vitamin B12 levels (p = 0,924). There was difference between genders for homocysteine (p = 0,035), but there was no significant difference for vitamin B12 (p = 0,584) and folate (p = 0,312). There was no difference between homocysteine levels of positive patients for H. pylori and H. pylori eradication in both genders (p > 0.5). Conclusions: The study showed no significant relationship between the serum levels of vitamin B12, folate, and homocysteine and the H. pylori infection in relation to H. pylori eradication in functional dyspeptic patients. Regarding homocysteine levels compared between genders, the values were higher in men.

Introdução: Dispepsia funcional é uma doença que possui critérios diagnósticos definidos por reuniões de consenso, conhecidos por critérios de Roma. Apresenta alta prevalência mundial, grande impacto social e redução na qualidade de vida do indivíduo. Helicobacter pylori está envolvida na patogênese da dispepsia funcional, sendo indicada sua detecção e erradicação no tratamento dos pacientes dispépticos funcionais. H. pylori também tem sido sugerida como um importante agente na etiologia de níveis baixos de Vitamina B12 no soro. A hiperhomocisteinemia secundária à deficiência de Vitamina B12 e folato podem constituir um risco para as doenças cardiovasculares. Objetivo: investigar a relação entre os níveis séricos de Vitamina B12, folato e homocisteína e infecção pelo H. pylori em pacientes dispépticos funcionais. Métodos: Foram incluídos pacientes dispépticos funcionais, pelos critérios de Roma III do estudo HEROES (Helicobacter Eradication Relief of Dyspeptic Symptoms) - ClinicalTrials.gov número NCT00404534. Os pacientes dispépticos que apresentaram positividade para H. pylori foram randomizados para erradicação da bactéria com antibiticoterapia oral ou placebo. Após doze meses realizaram o segundo exame endoscópico com mesma metodologia. Da amostra total, 77 continuaram positivos para a infecação por H. pylori e 77 tiveram como resultado a erradicação da bactéria H. pylori, ou seja, negativaram. O material biológico foi previamente coletado e armazenado, além dos respectivos dados demográficos e clínicos. As amostras foram armazenadas a -80◦C em ependorf e realizadas medidas em soro dos níveis de vitamina B12 e folato e homocisteína. Resultados: Da amostra total, 77 pacientes eram H. pylori positivo (15 homens e 62 mulheres) e 77 eram H.pylori erradicados (21 homens e 56 mulheres). A média de idade foi de 47,8±11,5, em relação à idade e gênero não houve diferença significativa entre os grupos (p > 0,05). Quanto aos resultados reunidos em categorias (níveis de vitamina B12, folato e homocisteína), conforme os pontos de corte usados na literatura, não foi observada diferença estatisticamente significativa entre os dois grupos de pacientes (p > 0,6). Não houve correlação entre idade e níveis de vitamina B12 (p = 0,924). Houve diferença entre gêneros para homocisteína (p = 0,035), porém não houve significância para vitamina B12 (p = 0,584) e folato (p = 0,312). Não houve diferença entre níveis de homocisteína de pacientes H. pylori positivos e H. pylori erradicados para ambos os gêneros (p > 0,5). Conclusões: O presente estudo demonstrou que não houve relação significativa entre os níveis séricos de Vitamina B12, folato e homocisteína e infecção por H. pylori em relação aos H. pylori erradicados nos dispépticos funcionais. E quanto aos níveis de homocisteína comparados entre gêneros, os valores foram mais altos em homens. / Introduction: Functional dyspepsia a disease which has diagnosis criteria defined by consensus gatherings, known as the Rome criteria. It is highly prevalent worldwide, has great social impact, and reduces the quality of life of individuals. Helicobacter pylori is involved in the pathogenesis of functional dyspepsia, and its detection and eradication are indicated in the treatment of functional dyspepsia patients. H. pylori has also been suggested as an important agent in the etiology of low levels of vitamin B12 in serum. A hyperhomocysteinemia secondary to vitamin B12 and folate deficiencies could pose a risk for cardiovascular diseases. Objective: To investigate the relationship among the serum levels of Vitamin B12, folate and homocysteine, and the H. pylori infection in functional dyspeptic patients. Methodology: A group of patients with functional dyspepsia was included, following the Rome III criteria from the study HEROES (Helicobacter Eradication Relief of Dyspeptic Symptoms) – ClinicalTrials.gov number NCT00404534. The dyspeptic patients who were positive for H. pylori in tissue biopsy were randomized to eradication of the bacteria with oral antibiotic therapy or placebo. After twelve months, a second endoscopy was performed with the same methodology. Of the total sample, 77 patients remained positive for H. pylori and 77 patients had as a result the eradication of H. pylori bacteria, that is, they became negative. The biological material was previously collected and stored, besides its demographic and clinical data. The samples were stored at -80◦C in Eppendorf, they were measured in the serum of vitamin B12 folate and homocysteine levels. Results: Of the total sample, 77 patients were positive for H. pylori (15 men, 62 women) and 77 patients had the eradication of H. pylori (21 men, 56 women). The average age of the sample was about 47,8±11,5,regarding age and gender, it was not observed significant difference between the groups (p > 0,05). Concerning the results gathered into categories (the levels of vitamin B12, folate, and homocysteine), as the cut off points used in the literature, it was not observed statistically significant difference between the two groups of patients (p > 0,6). There was no correlation between age and vitamin B12 levels (p = 0,924). There was difference between genders for homocysteine (p = 0,035), but there was no significant difference for vitamin B12 (p = 0,584) and folate (p = 0,312). There was no difference between homocysteine levels of positive patients for H. pylori and H. pylori eradication in both genders (p > 0.5). Conclusions: The study showed no significant relationship between the serum levels of vitamin B12, folate, and homocysteine and the H. pylori infection in relation to H. pylori eradication in functional dyspeptic patients. Regarding homocysteine levels compared between genders, the values were higher in men.