Persistence of Breakage in Specific Chromosome Bands 6 Years after Acute Exposure to Oil

Abstract

BackgroundThe identification of breakpoints involved in chromosomal damage could help to detect genes involved in genetic disorders, most notably cancer. Until now, only one published study, carried out by our group, has identified chromosome bands affected by exposure to oil from an oil spill. In that study, which was performed two years after the initial oil exposure in individuals who had participated in clean-up tasks following the wreck of the Prestige, three chromosomal bands (2q21, 3q27, 5q31) were found to be especially prone to breakage. A recent follow-up study, performed on the same individuals, revealed that the genotoxic damage had persisted six years after oil exposure.ObjectivesTo determine whether there exist chromosome bands which are especially prone to breakages and to know if there is some correlation with those detected in the previous study. In addition, to investigate if the DNA repair problems detected previously persist in the present study.DesignFollow-up study performed six years after the Prestige oil spill.SettingFishermen cooperatives in coastal villages.ParticipantsFishermen highly exposed to oil spill who participated in previous genotoxic study six years after the oil.MeasurementsChromosome damage in peripheral lymphocytes. For accurate identification of the breakpoints involved in chromosome damage of circulating lymphocytes, a sequential stain/G-banding technique was employed. To determine the most break-prone chromosome bands, two statistical methods, the Fragile Site Multinomial and the chi-square tests (where the bands were corrected by their length) were used. To compare the chromosome lesions, structural chromosome alterations and gaps/breaks between two groups of individuals we used the GEE test which takes into account a possible within-individual correlation. Dysfunctions in DNA repair mechanisms, expressed as chromosome damage, were assessed in cultures with aphidicolin by the GEE test.ResultsCytogenetic analyses were performed in 47 exposed individuals. A total of 251 breakpoints in exposed individuals) were identified, showing a non-uniform distribution in the human ideogram. Ten chromosome bands were found to be especially prone to breakage through both statistical methods. By comparing these bands with those observed in certain exposed individuals who had already participated the previous study, it was found in both studies that four bands (2q21, 3q27, 5q31 and 17p11.2) are particularly sensitive to breakage. Additionally, the dysfunction in DNA repair mechanisms was not significantly higher in oil-exposed individuals than in non-exposed individuals.LimitationsThe sample size and the possibility of some kind of selection bias should be considered. Genotoxic results cannot be extrapolated to the high number of individuals who participated occasionally in clean-up tasks.ConclusionOur findings show the existence of at least four target bands (2q21, 3q27, 5q31 and 17p11.2) with a greater propensity to break over time after an acute exposure to oil. The breaks in these b...

Large-scale correlations between eight key double strand break related data sets over the whole human genome

“…Furthermore, the genome-wide study of hot spots of DNA double-strand breaks in human cells 37 not surprisingly show a strong correlation not least with the presently studied radiation-induced breaks, the CpG density and the Hap Map data. Similarly, the recent study of breakage in specific chromosome bands after acute exposure to oil and benzene show similar correlations and close association to fragile sites 38 . The recent genome wide study of p53 pathway cancer related Single Nucleotide Polymorphisms and expression quantitative trait loci 39 both agree very well with the presently described radiation-induced Chromatid Breakage points and both types of Fragile Sites.…”

“…In average 33% of the common RIBs are collocated with 41% of the FSs respectively, and then practically always in regions of elevated recombination, MLH1 immunofluorescence and chiasma density as seen in Fig 6. The observed large-scale correlation between HapMap recombination sites, chiasma, MLH1 immunofluorescence and highly probable RIBs as seen in Figures 2-6 is striking, even though there seems too be some local deviations. This may also be expected due to use of different population averages in the former datasets, such as when using germ cells from males or females and cells from other tissues, but also due to the wide range of genomic variability over the human genome and the associated genomic instability and hyper mutation in human cancers [32][33][34][35][36][37][38][39][40][41][42][43][44] . In breast cancer patients with poor prognosis 23 on average 69% of the CNCs are located at X-ray RIBs covering less than 20% of the genome, whereas 49% of the CNCs are located in the common and rare FS regions covering about 27% of the genome.…”

“…The present study has also shown that only 3% of 782 CNCs are alone outside these regions (cf Fig7) and missing other CNCs, in severely malignant breast cancers. Many of the RIBs may therefore be regarded as a new type of more localized DNA repair fragility likely to be involved also in other types of cancers, and most likely, without the need for exposer to ionizing radiations [9][10][11][12] or benzene 38 that first identified their existence.…”

Cancer Incidence Trend in the Hebei Spirit Oil Spill Area, from 1999 to 2014: An Ecological Study

“…In a study conducted 1.5 years [ 13 ] after the spill, the oxidative DNA stress marker levels, which could be indicative of cancer risk, were higher in the high-exposure group than in the low-exposure group; the effect persisted for 6 years after the spill [ 14 ]. Chromosome damage was observed among fishermen in studies conducted two and six years after the Prestige oil spill in Spain [ 15 , 16 , 17 ], and cancer risk modeling was performed after the British Petroleum Deepwater Horizon (BPDH) oil spill in the United States of America (USA) [ 18 ].…”

Long-Term Respiratory and Genotoxic Effects in The Prestige Oil Spill

“…A long-term genotoxic study, conducted in 52 exposed and 23 non-exposed individuals, showed that structural alterations remained high in exposed individuals, although the association with the exposure to the oil spill could not be substantiated because there was a relevant increase of structural alterations in nonexposed individuals 15 . Nevertheless, 2p23 and 2q23 chromosome bands were only detected in exposed individuals 16 The main results of the SEPAR-Prestige Study are summarised in table 2.…”