Increased sister chromatid exchanges in peripheral lymphocytes of patients with Crohn's disease

Cytogenetic outcomes of adjuvant chemotherapy in non-target cells of breast cancer patients

Spontaneous and chemotherapy-induced sister chromatid exchanges (SCES) and lymphocyte proliferation rate index (PRI) in cultured peripheral lymphocytes were evaluated in 30 patients with diagnosed breast cancer before and after adjuvant chemotherapy and in 30 healthy women with no known familial history of breast cancer. Before chemotherapy, the breast cancer patients had a significantly increased background level of SCE, and lowered PRI as compared with the healthy women. Marked inter-individual variations were observed in both endpoints among the patients. Significantly elevated frequency of SCE and depressed PRI were recorded in blood samples collected after the first cycle of chemotherapy, with high inter-individual variations in the responses to the chemotherapy. FAC (5-fluorouracil, adriamycin and cyclophosphamide) protocol was the most genotoxic of the protocols studied, but also AC (adriamycin, cyclophosphamide) and CMF (cyclophosphamide, methotrexate and 5-fluorouracil) clearly increased SCE. All protocols significantly retarded lymphocyte proliferation in vitro. Our findings indicate that both SCE and PRI may serve as sensitive biomarkers for the routine detection of critical lesions produced by the administration of antineoplastic drugs in the clinical setting, as well as for possible screening of high-risk individuals among patients who have successfully completed chemotherapy. Human & Experimental Toxicology (2007) 26 , 391—399

Effects of infliximab on sister chromatid exchanges and chromosomal aberration in patients with rheumatoid arthritis

The aim of this study was to evaluate in a 24-weeks the effect of anti-TNF-alpha, infliximab, on cytogenetic biomarkers in peripheral lymphocytes of patients with rheumatoid arthritis (RA). A total of 40 patients with RA met the criteria to be treated with methotrexate (15 mg/week) were evaluated. Twenty patients, randomly selected, were treated with infliximab in addition to methotrexate (group I), whereas the other 20 patients continued with only methotrexate treatment (group M). Twenty healthy volunteers matched for age, gender and smoking habits served as control group (group C). At baseline, sister chromatid exchange rate was 7.20 ± 2.21 in group I, 7.40 ± 1.60 in group M and 4.97 ± 1.32 in group C (P < 0.01 vs group I and M). After 24-weeks, sister chromatid exchange rate was 7.87 ± 2.54 in group I and 7.81 ± 1.95 in group M (P = ns). High frequency cells count was 4.9 % and 4.7 % in the groups I and M, respectively, at the end of the study (P = ns). The basal chromosomal aberration frequency was 4.90 % in group I and 5.20 % in groups M; after 24-weeks, this was 5.10 % in group I and 5.10 % in groups M (P = ns). Infliximab treatment, for 24 weeks, did not increase the cytogenetic biomarkers in patients with RA. Our data show that the use of infliximab has not a genotoxic effect in patients with RA.

Chemistry meets biology in colitis-associated carcinogenesis

The intestine comprises an exceptional venue for a dynamic and complex interplay of numerous chemical and biological processes. Here, multiple chemical and biological systems, including the intestinal tissue itself, its associated immune system, the gut microbiota, xenobiotics, and metabolites meet and interact to form a sophisticated and tightly regulated state of tissue homoeostasis. Disturbance of this homeostasis can cause inflammatory bowel disease (IBD)-a chronic disease of multifactorial etiology that is strongly associated with increased risk for cancer development. This review addresses recent developments in research into chemical and biological mechanisms underlying the etiology of inflammation-induced colon cancer. Beginning with a general overview of reactive chemical species generated during colonic inflammation, the mechanistic interplay between chemical and biological mediators of inflammation, the role of genetic toxicology, and microbial pathogenesis in disease development are discussed. When possible, we systematically compare evidence from studies utilizing human IBD patients with experimental investigations in mice. The comparison reveals that many strong pathological and mechanistic correlates exist between mouse models of colitis-associated cancer, and the clinically relevant situation in humans. We also summarize several emerging issues in the field, such as the carcinogenic potential of novel inflammation-related DNA adducts and genotoxic microbial factors, the systemic dimension of inflammation-induced genotoxicity, and the complex role of genome maintenance mechanisms during these processes. Taken together, current evidence points to the induction of genetic and epigenetic alterations by chemical and biological inflammatory stimuli ultimately leading to cancer formation.

Chromosomal aberrations in peripheral blood lymphocytes in patients with newly diagnosed celiac and Crohn's disease

OBJECTIVES

The aims of this research were to determine the number of chromosomal aberrations in peripheral blood lymphocytes and to evaluate the number of circulating lymphocytes with CD103, integrin expressed on intraepithelial lymphocytes and preserved in enteropathy-associated T-cell lymphoma, in patients with newly diagnosed Crohn's disease, celiac disease, and healthy controls.

METHODS

During the period of 30 months, we included 44 patients. Chromosome aberrations were analyzed in peripheral blood lymphocytes by a single cytogeneticist. Multicolor flow cytometric was used for immunophenotyping of peripheral blood lymphocytes.

RESULTS

We found a significantly higher number of chromosomal aberrations/100 metaphases in the celiac and Crohn's disease group compared with the controls (P=0.01) and they also had a significantly higher number of aberrant cells compared with the controls (P<0.001). There was no statistically significant difference between the groups with respect to the percentage of CD103+ and CD8+CD103+ cells between groups (P=0.16 and 0.41, respectively) and no correlation between the total number of chromosomal aberrations and the percentage of CD103+ and CD8+CD103+ cells (P=0.06 and 0.06, respectively).

CONCLUSION

Patients with active celiac and newly diagnosed Crohn's disease, before treatment initiation, have a significantly increased number of chromosomal aberrations in peripheral blood lymphocytes. No dissemination of intraepithelial cells in the blood and correlation to the chromosomal aberration was found.

Evidence for somatic gene conversion and deletion in bipolar disorder, Crohn's disease, coronary artery disease, hypertension, rheumatoid arthritis, type-1 diabetes, and type-2 diabetes

BACKGROUND

During gene conversion, genetic information is transferred unidirectionally between highly homologous but non-allelic regions of DNA. While germ-line gene conversion has been implicated in the pathogenesis of some diseases, somatic gene conversion has remained technically difficult to investigate on a large scale.

METHODS

A novel analysis technique is proposed for detecting the signature of somatic gene conversion from SNP microarray data. The Wellcome Trust Case Control Consortium has gathered SNP microarray data for two control populations and cohorts for bipolar disorder (BD), cardiovascular disease (CAD), Crohn's disease (CD), hypertension (HT), rheumatoid arthritis (RA), type-1 diabetes (T1D) and type-2 diabetes (T2D). Using the new analysis technique, the seven disease cohorts are analyzed to identify cohort-specific SNPs at which conversion is predicted. The quality of the predictions is assessed by identifying known disease associations for genes in the homologous duplicons, and comparing the frequency of such associations with background rates.

RESULTS

Of 28 disease/locus pairs meeting stringent conditions, 22 show various degrees of disease association, compared with only 8 of 70 in a mock study designed to measure the background association rate (P < 10-9). Additional candidate genes are identified using less stringent filtering conditions. In some cases, somatic deletions appear likely. RA has a distinctive pattern of events relative to other diseases. Similarities in patterns are apparent between BD and HT.

CONCLUSIONS

The associations derived represent the first evidence that somatic gene conversion could be a significant causative factor in each of the seven diseases. The specific genes provide potential insights about disease mechanisms, and are strong candidates for further study.

Well-trained, healthy triathletes experience no adverse health risks regarding oxidative stress and DNA damage by participating in an ultra-endurance event

Also physical exercise in general is accepted to be protective, acute and strenuous exercise has been shown to induce oxidative stress. Enhanced formation of free radicals leads to oxidation of macromolecules and to DNA damage. On the other hand ultra-endurance events which require strenuous exercise are very popular and the number of participants is continuously increasing worldwide. Since only few data exists on Ironman triathletes, who are prototypes of ultra-endurance athletes, this study was aimed at assessing the risk of oxidative stress and DNA damage after finishing a triathlon and to predict a possible health risk. Blood samples of 42 male athletes were taken 2 days before, within 20 min after the race, 1, 5 and 19 days post-race. Oxidative stress marker increased only moderately after the race and returned to baseline after 5 days. Marker of DNA damage measured by the SCGE assay with and without restriction enzymes as well as by the sister chromatid exchange assay did either show no change or deceased within the first day after the race. Due to intake during the race and the release by the cells plasma concentrations of vitamin C and α-tocopherol increased after the event and returned to baseline 1 day after. This study indicates that despite a temporary increase in some oxidative stress markers, there is no persistent oxidative stress and no DNA damage in response to an Ironman triathlon in trained athletes, mainly due to an appropriate antioxidant intake and general protective alterations in the antioxidant defence system.

The genotoxic risk in health care workers occupationally exposed to cytotoxic drugs--a comprehensive evaluation by the SCE assay

Present study aimed at an integral assessment of sister chromatid exchange (SCE) frequencies in the health care workers occupationally exposed to cytostatics. The results of 500 individual analyses were evaluated. Drug handling practice was investigated in parallel and the results showed that cytostatics are mostly prepared outside hospital pharmacy (98%) and mainly handled by nurses (96%). Mean frequency of SCE was 5.63 +/- 2.28, while HFC represented 9.65% of the cells analysed. Both values were higher compared to previously established control values for Croatian population. The duration of exposure, profession, age, gender, smoking habit, medical exposures, and simultaneous exposure to other occupational mutagens significantly contributed to SCE and HFC values. The usefulness both biomarkers in the assessment of cytogenetic damage is confirmed. Since current practice in Croatian hospitals does not include regular monitoring of workplaces, to ensure maximal occupational safety, a surveillance on exposed health care workers, including periodic biomonitoring, is recommended.

Alteration of sister chromatid exchange frequencies in gastric cancer and chronic atrophic gastritis patients with and without H. pylori infection

AIM

To determine, by counting sister chromatid exchange (SCE) frequencies, whether genetic impairment and DNA damage have an effect on the pathogenesis of gastric cancer (GC).

METHODS

Analysis of SCE is a cytogenetic technique used to show DNA damage as a result of an exchange of DNA fragments between sister chromatids. We analyzed SCE frequency in 24 patients with GC, 26 patients with chronic atrophic gastritis (CAG), and 15 normal controls. The presence of H. pylori was confirmed by urease test, toluidine-blue stain and hematoxylin-eosin stain.

RESULTS

SCE was significantly increased in H. pylori-negative GC patients, and in H. pylori-negative CAG patients compared with controls (7.41 +/- 1.36 and 6.92 +/- 1.20, respectively, vs 5.54 +/- 0.8, P < 0.001). There was no difference in the SCE frequency between H. pylori-negative GC patients and H. pylori-negative CAG patients (P > 0.05). On other hand, the SCE frequencies in H. pylori-positive GC patients were higher than those in H. pylori-positive CAG patients (9.20 +/- 0.94 vs 7.93 +/- 0.81, P < 0.01). Furthermore, H. pylori-positive GC patients had a higher SCE frequency than H. pylori-negative GC patients (9.20 +/- 0.94 vs 7.41 +/- 1.36, P < 0.001). Similarly, a significant difference was detected between H. pylori-positive CAG patients and H. pylori-negative CAG patients (7.93 +/- 0.81 vs 6.92 +/- 1.20, P < 0.05).

CONCLUSION

We suggest the increased SCE in patients reflects a genomic instability that may be operative in gastric carcinogenesis.

Cytogenetic damage in blood lymphocytes and exfoliated epithelial cells of children with inflammatory bowel disease

This longitudinal, prospective study sought to establish whether pediatric Crohn's disease (CD) and ulcerative colitis (UC) are associated with increased levels of cytogenetic damage and whether folate supplementation in combination with other treatments mitigates cytogenetic damage in children with inflammatory bowel disease (IBD). After a 1-mo treatment and folate supplementation, all clinical tests in CD (n = 24) and UC (n = 17) patients improved. Patients with CD were comparable in the cytogenetic response with controls (n = 28) assessed by micronucleus (MN) assay, but both groups differed from the UC group. While the MN frequency in epithelial cells slightly decreased from first to second observations in CD patients (p = 0.05) and controls (p = 0.11), an increase was observed in UC patients (p = 0.001). Similar changes were observed in blood lymphocytes resulting in significantly higher levels of the MNs and chromosome bridges in UC patients. These preliminary findings of a difference in chromosome damage between pediatric UC patients compared with CD patients and healthy controls warrant confirmation and expansion to determine (1) the role of cytogenetic damage in the pathogenesis of these diseases, (2) relative contribution of treatment and folate supplementation, and (3) potential links to the eventual development of cancer in some patients.

Frequency of sister chromatid exchanges in the lymphocytes of patients with atopic dermatitis

The combination of genetic susceptibility and environmental factors can induce allergic sensitization and subsequent local inflammation, resulting in atopic dermatitis (AD). Sister chromatid exchange (SCE) is a sensitive method that may reflect an instability in DNA or a deficiency in DNA repair. The aim of the present study was to investigate whether patients with AD have defects in DNA repair and whether SCE frequency can be used as a genetic marker in the pathogenesis of AD. Between September 2004 and July 2005, SCE was analyzed in the peripheral blood lymphocyte chromosomes of 32 patients with AD and 28 control subjects at the Dermatology Unit of Erzurum State Hospital. This study found that the SCE frequency was significantly increased in patients with AD (P < 0.00001). The prevalence of SCE was not correlated with patient age, sex, disease duration or AD disease severity. Our results indicate that increased chromosome instability may play an important role in the etiology of AD.

Delineation of the chemical pathways underlying nitric oxide-induced homologous recombination in mammalian cells

Inflammation is an important risk factor for cancer. During inflammation, macrophages secrete nitric oxide (NO*), which reacts with superoxide or oxygen to create ONOO- or N2O3, respectively. Although homologous recombination causes DNA sequence rearrangements that promote cancer, little was known about the ability of ONOO- and N2O3 to induce recombination in mammalian cells. Here, we show that ONOO- is a potent inducer of homologous recombination at an integrated direct repeat substrate, whereas N2O3 is relatively weakly recombinogenic. Furthermore, on a per lesion basis, ONOO(-)-induced oxidative base lesions and single-strand breaks are significantly more recombinogenic than N2O3-induced base deamination products, which did not induce detectable recombination between plasmids. Similar results were observed in mammalian cells from two different species. These results suggest that ONOO(-)-induced recombination may be an important mechanism underlying inflammation-induced cancer.

Impact of antiseptics on radical metabolism, antioxidant status and genotoxic stress in blood cells: povidone-iodine versus octenidine dihydrochloride

No sufficient data are available of the of antiseptics' influence on human blood cells. Effects of two antiseptics, povidone-iodine (PVD-I) versus octenidine dihydrochloride (OD), were tested on antioxidant status, radical formation, antioxidant defence enzymes and genotoxic stress in blood cells, in vitro. Human blood was taken by venipuncture, enriched with PVD-I or OD (0.0001-20% final concentration) and incubated at 37 degrees C between 30 and 120 min. alpha-Tocopherol was assessed in erythrocytes and granulocytes. Superoxide-dismutase (SOD) and glutathione (GSH) were determined in erythrocytes, the total anti-oxidative capacity (TAC) and malondialdehyde (MDA) in their ghosts. In granulocytes status of hydrogen peroxide (H(2)O(2)), superoxide anions and MDA was observed. Genotoxic stress was determined by counting sister chromatide exchanges (SCE) in lymphocytes after enrichment within 0.05-0.4% of antiseptics. Based on all biomarker tested, concentrations up to 0.05% incubated for 30 min did not affect cell metabolism. 1% and 10% PVD-I reduced the activity of SOD (-40%), GSH (-62%) and the content of alpha-tocopherol more than OD (p<0.05). No significant differences between the antiseptics were observed for TAC and MDA. H(2)O(2) and superoxide anions were significantly reduced after the 10% addition for both substances independent on the exposure. Without having changes in lipid oxidation, the reduction of antioxidative defence mechanisms must be due to the oxidation caused by the antiseptics, mainly PVD-I. An increased SCE rate was neither observed with PVD-I nor with OD within an enrichment with 0.05-0.4%. Higher concentrations (1% and more) could not be tested on SCE formation because they caused cell bursts. The results presented indicate that concentrations up to 0.05% incubated for 30 min are safe for exposing blood cells of healthy subjects.

Genotoxicity and mutagenicity of melanoidins isolated from a roasted glucose–glycine model in human lymphocyte cultures, intestinal Caco-2 cells and in the Salmonella typhimurium strains TA98 and TA102 applying the AMES test

Melanoidins are formed during household cooking procedures and are part of our daily diet, but data on their toxicological potential are still scarce. Therefore, the mutagenic, cytotoxic and genotoxic activity of the water soluble total fraction (sol A), the water soluble high molecular weight fraction (HMW; Molecular weight>12,400 Da) and the remaining water soluble low molecular weight fraction (LMW) isolated from a glucose-glycine model system roasted at 125 degrees C was comprehensively studied in human lymphocytes (genetic end point: sister chromatid exchange (SCE)), Caco-2 cells (SCE, cell viability, cell proliferation) and in the Salmonella typhimurium strains TA98 and TA102 (Ames test). Tests were performed in a dose- and time-dependent manner. The results indicate a significant increase in SCE formation in human lymphocytes after the exposure to 0.05% and 0.1% of the melanoidin fractions. In Caco-2 cells, only the exposure to LMW increased the SCE formation as a matter of concentration. Cell's proliferation and viability decreased significantly after exposure to melanoidins. In the AMES test, melanoidins did not show a mutagenic potential, neither using the TA98 nor the TA102 strain. These results show that melanoidins isolated from the glucose-glycine mixture exhibited modest but significant genotoxic effects in human lymphocytes and, in particular the LMW, in Caco-2 cells, but they induce neither in low nor in very high concentrations mutagenicity in bacteria strains.

Sister chromatid exchange (SCE) analysis in periodontitis

BACKGROUND

Emerging data indicate that genetic factors may be associated with the etiopathogenesis of aggressive periodontitis. Sister chromatid exchange (SCE) is a sensitive method that might reflect an instability of DNA or a deficiency of DNA repair. The aim of the present study was to investigate SCE frequency of patients with different forms of periodontal disease and to determine whether this cytogenetic marker in patients with aggressive periodontitis can be differential compared to patients with chronic periodontitis and control subjects.

METHODS

SCE was analysed in peripheral blood lymphocyte chromosomes of 13 patients with generalised aggressive periodontitis (G-AP), 10 patients with chronic periodontitis (CP) and 10 control subjects. The periodontal parameters of probing depth, clinical attachment level, the presence of bleeding on probing and plaque were recorded. Peripheral blood lymphocytes obtained from both patient groups and control subjects were cultured in the presence of 5-Bromo-2-deoxyuridine in complete darkness for 72 h. For scoring SCE frequency, 20 metaphases were studied from each donor.

RESULTS

The frequency of SCE was found to be 6.7 +/- 0.9 per cell in patients with G-AP, 6.5 +/- 1.5 per cell in CP patients and 6.9 +/- 1.1 in control subjects. No statistically significant differences were found between groups (p > 0.05).

CONCLUSIONS

The data indicate that there the cyotogenetic damage in the aggressive type of periodontal disease is not greater than in chronic periodontitis and control subjects. Although no aberrant cytogenetic damage was observed in different forms of periodontitis compared to control, this does not discount the importance of other genetic factors in the pathogenesis of periodontal disease.

Acute hepatotoxicity of the polycyclic musk 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphtaline (AHTN)

Synthetic musks are present in fine fragrances, cosmetics, soaps and laundry detergents. One of the most important synthetic musks is 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydro-naphthaline+ ++ (AHTN; annual production: about 1500 metric tons). An increasing number of studies show that AHTN accumulates in surface water and fish and can be detected in human adipose tissue, as well in human milk. In the present report it is shown that a single high dose of AHTN leads to acute hepatic damage in rats, characterized by single cell necrosis, inflammation, swelling of liver parenchymal cells, and the presence of cytoplasmic condensations in the hepatocytes, while at the ultrastructural level disorganization of the rough endoplasmic reticulum and mitochondria as well as focal cytolysis is evident. Furthermore, evidence is presented that AHTN is not genotoxic, does not induce peroxisome proliferation, and does not lead to the induction of drug-metabolizing enzymes as phenobarbital and 3-methylcholanthrene do.