A study protocol for the evaluation of occupational mutagenic/carcinogenic risks in subjects exposed to antineoplastic drugs: a multicentric project

<p>Abstract</p> <p>Background</p> <p>Some industrial hygiene studies have assessed occupational exposure to antineoplastic drugs; other epidemiological investigations have detected various toxicological effects in exposure groups labeled with the job title. In no research has the same population been studied both environmentally and epidemiologically. The protocol of the epidemiological study presented here uses an integrated environmental and biological monitoring approach. The aim is to assess in hospital nurses preparing and/or administering therapy to cancer patients the current level of occupational exposure to antineoplastic drugs, DNA and chromosome damage as cancer predictive effects, and the association between the two.</p> <p>Methods/Design</p> <p>About 80 healthy non-smoking female nurses, who job it is to prepare or handle antineoplastic drugs, and a reference group of about 80 healthy non-smoking female nurses not occupationally exposed to chemicals will be examined simultaneously in a cross-sectional study. All the workers will be recruited from five hospitals in northern and central Italy after their informed consent has been obtained.</p> <p>Evaluation of surface contamination and dermal exposure to antineoplastic drugs will be assessed by determining cyclophosphamide on selected surfaces (wipes) and on the exposed nurses' clothes (pads). The concentration of unmetabolized cyclophosphamide as a biomarker of internal dose will be measured in end-shift urine samples from exposed nurses.</p> <p>Biomarkers of effect and susceptibility will be assessed in exposed and unexposed nurses: urinary concentration of 8-hydroxy-2-deoxyguanosine; DNA damage detected using the single-cell microgel electrophoresis (comet) assay in peripheral white blood cells; micronuclei and chromosome aberrations in peripheral blood lymphocytes. Genetic polymorphisms for enzymes involved in metabolic detoxification (i.e. glutathione <it>S</it>-transferases) will also be analysed.</p> <p>Using standardized questionnaires, occupational exposure will be determined in exposed nurses only, whereas potential confounders (medicine consumption, lifestyle habits, diet and other non-occupational exposures) will be assessed in both groups of hospital workers.</p> <p>Statistical analysis will be performed to ascertain the association between occupational exposure to antineoplastic drugs and biomarkers of DNA and chromosome damage, after taking into account the effects of individual genetic susceptibility, and the presence of confounding exposures.</p> <p>Discussion</p> <p>The findings of the study will be useful in updating prevention procedures for handling antineoplastic drugs.</p

Genetic polymorphisms involved in folate metabolism and elevated plasma concentrations of homocysteine: maternal risk factors for Down syndrome in Brazil

The aim of the present study was to investigate the effect of polymorphisms C677T and A1298C in the methylenetetrahydrofolate reductase (MTHFR) gene, A2756G in methionine synthase reductase (MTR) gene and A80G in reduced folate carrier 1 (RFC1) gene, and plasma homocysteine (Hcy), on the maternal risk for Down syndrome (DS). Seventy-two DS mothers and 194 mothers who had no children with DS were evaluated. The investigation of the MTHFR C677T, MTR A2756G and RFC1 A80G polymorphisms was performed by polymerase chain reaction and enzyme digestion and the MTHFR A1298C polymorphism by allele-specific polymerase chain reaction. Hcy quantification was carried out by liquid chromatography-tandem mass spectrometry. The median number of polymorphic alleles for the four loci tested was greater in DS mothers compared to the control group, and the presence of three or more polymorphic alleles increased the risk for having a child with DS 1.74 times. Elevated maternal risk for DS was also observed when plasma Hcy concentration was higher than 4.99 mu mol/L. In conclusion, the presence of three or more polymorphic alleles for MTHFR C677T, MTHFR A1298C, MTR A2756G, and RFC1 A80G, and plasma Hcy concentrations higher than 4.99 mu mol/L are maternal risk factors for DS.71334

Combination of angiotensin-converting enzyme and methylenetetrahydrofolate reductase gene polymorphisms as determinant risk factors for chronic allograft dysfunction

Objective. The aim of this study was to investigate the frequency of gene angiotensincoVerting enzyme insertion/deletion (ACE I/D) and methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) variants, as well as to evaluate the plasma homocysteine concentrations in 217 patients who underwent renal transplantation at least 12 months prior to define risk factors for chronic allograft dysfunction. Methods. The presence of the polymorphism ACE deletion was assessed by polymerase chain reaction (PCR) analysis. MTHFR polymorphisms were determined by PCR and restriction fragment length polymorphism (RFPL) techniques. The restriction enzymes were Hinf I and Mbo II for MTHFR variants C677T and A1298C, respectively. Plasma homocysteine concentrations were measured by liquid chromatography-tandem mass spectrometry (LS-MS/MS). Results. Hyperhomocysteinernias were more common in patients with chronic allograft dysfunction (P =.004). No statistically significant differences were observed between the allelic and genotypic distributions of MTHFR and ACE polymorphisms. An effective risk factor was found when the polymorphisms of the ACE and MTHFR genes and hyperhomocysteinemia were associated (odds ratio 2.51; 95% confidence interval 1.19-5.28). In conclusion, our study identified that the presence of hyperhomocysteinernia in combination with unfavorable genotypes contributes to an increased risk for development of chronic allograft dysfunction.391788

Hyperhomocysteinemia and MTHFR C677T and A1298C polymorphisms are associated with chronic allograft nephropathy in renal transplant recipients

Hyperhomocysteine has been reported to be an important risk factor for the development of atherosclerosis. Identification of risk factors, such as hyperhomocysteinemia, is crucial for a better understanding of the events that lead to degenerative processes in the vascular system and for a correct understanding of the potential role of methylene-tetrahydrofolate reductase enzymes (MTHFR) to help in the treatment of vascular disease observed in chronic allograft nephropathy (CAN). In this study we analyzed the plasma homocysteine concentrations and MTHFR C677T and A1298C polymorphism frequencies among 110 renal transplant recipients (53 with CAN and 57 with normal renal function). All recipients had undergone renal transplantation at least 12 months prior to this investigation to establish a possible correlation with the posttransplant outcome. Plasma homocysteine concentrations were measured by liquid chromatography-tandem mass spectrometry and MTHFR polymorphisms were investigated by the PCR-RFLP technique. The results demonstrated that in renal transplant recipients, hyperhomocysteinemia in addition to the presence of the allelic variants for both MTHFR polymorphisms (677T/1298C) might play a role as an additional risk factor for CAN. We understand that analysis of these polymorphisms might have a role in the CAN process. Therefore, studies to evaluate their presence in renal transplant patients may be extremely useful to individualize immunosuppressive protocols to inhibit or retard the progression of CAN.36102979298

Effect of folate, vitamin B-6, and vitamin B-12 intake and MTHFR C677T polymorphism on homocysteine concentrations of renal transplant recipients

Plasma hyperhomocysteinemia (HHcy) is considered a risk factor for chronic allograft dysfunction (CAD), the main cause of functional loss in transplant recipients. Genetic polymorphisms that alter enzymes involved in homocysteine (Hcy) metabolism, such as methylenetetrahydrofolate reductase (MTHFR), and vitamin deficiency can result in HHcy. The objectives of this study were to investigate the relationship between HHcy and CAD development, and to evaluate the effect of intake of folate and vitamins B-6 and 13,2 as well as MTHFR C677T polymorphism on Hcy concentrations. Ninety-eight renal transplant recipients including 48 showing CAD and 50 with normal renal function (NRF), were included in this cross-sectional study. Peripheral blood samples were collected for plasma Hcy quantification by liquid chromatography/sequential mass spectrometry (LC-MS/MS), and for MTHFR polymorphism analysis using polymerase chain reaction-restriction fragment length polymorphism. Dietary intake was evaluated using a nutritional questionnaire. HHcy (P =.002) and higher mean concentrations of Hcy (P =.029) were associated with CAD. An association was observed between HHcy and 677T variant allele in the CAD group (P =.0005). There was no correlation between Hcy concentration and folate, vitamin B-6 or vitamin B-12 intake in the CAD group. However, a negative correlation was observed between Hcy concentration and folate intake (P =.043), and also between Hcy concentration and vitamin 136 intake (P =.030) in the NRF group. According to our study, HHcy is associated with CAD development. In patients with CAD, MTHFR polymorphism seems to have a greater effect on the Hey concentration than the vitamin intake. Increased folate and vitamin B, intakes seem to reduce Hcy concentrations among transplant recipients with NRF, and could contribute to reducing the risk of CAD development.39103163316

DHFR 19-bp Deletion and SHMT C1420T Polymorphisms and Metabolite Concentrations of the Folate Pathway in Individuals with Down Syndrome

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Background: Down syndrome (DS) results from the presence and expression of three copies of the genes located on chromosome 21. Studies have shown that, in addition to overexpression of the Cystathionine beta-synthase (CBS) gene, polymorphisms in genes involved in folate/homocysteine (Hcy) metabolism may also influence the concentrations of metabolites of this pathway. Aim: Investigate the association between Dihydrofolate reductase (DHFR) 19-base pair (bp) deletion and Serine hydroxymethyltransferase (SHMT) C1420T polymorphisms and serum folate and plasma Hcy and methylmalonic acid (MMA) concentrations in 85 individuals with DS. Methods: Molecular analysis of the DHFR 19-bp deletion and SHMT C1420T polymorphisms was performed by polymerase chain reaction (PCR) by difference in the size of fragments and real-time PCR allelic discrimination, respectively. Serum folate was quantified by chemiluminescence and plasma Hcy and MMA by liquid chromatography-tandem mass spectrometry. Results: Individuals with DHFR DD/SHMT TT genotypes presented increased folate concentrations (p = 0.004) and the DHFR II/SHMT TT genotypes were associated with increased MMA concentrations (p = 0.008). In addition, the MMA concentrations were negatively associated with age (p = 0.04). Conclusion: There is an association between DHFR DD/SHMT TT and DHFR II/SHMT TT combined genotypes and folate and MMA concentrations in individuals with DS.174274277Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [302157/2008-5, 119404/2009-5, 119419/2009-2