Aberrant crypt foci: endoscopic assessment and cell kinetics characterization

Rectal aberrant crypt foci (ACF) as a predictor of benign and malignant neoplastic lesions in the large intestine

Background

The importance of ACF is not fully explained, however, their number may be a good predictor of synchronous and metachronic adenoma or other polyps whose removal reduces the risk of CRC. Due to the epidemiological and genetic association of ACF with pre-cancer lesions, they may be a potential CRC biomarker. The aim of our study was to show that the number and type of rectal ACF may be a good predictive factor for the presence of polyps located proximally from the splenic flexure and that the type and number of ACF can correlate with the number and specific types of polyps in the large intestine.

Methods

The study included 131 patients who underwent colonoscopy combined with rectal mucosa staining with 0.25% methylene blue. The number of rectal ACF was determined and bioptats were sampled for histopathological examination to assess the type of ACF. Endoscopic ACF assessment criteria given by L. Roncucci were used. The obtained material was subjected to statistical analysis using probability distribution, U-test, t-student test, and chi ² as well as the Statistica 7.1 software package.

Results

The study population was divided into three subgroups according to the number of ACF observed, i.e. ACF < 5, 5–10 and > 10. ACF < 5 were found in 35 patients (29.41%), 5–10 ACF in 70 (58.82%) and ACF > 10 in 14 individuals (11.76%).

The study revealed the presence of normal ACF (p = 0.49), hyperplastic ACF (p = 0.34), dysplastic ACF (p = 0.11), and mixed ACF (p = 0.06). A single type of ACF was most commonly observed (n = 88, p = 0.74). In the researched group a larger number of ACF is concurrent with adenomas and hyperplastic polyps. The number of ACF clearly correlates with the dysplasia advancement in the adenoma and the number of polyps found.

Conclusions

Rectal ACF are a useful marker for the presence of cancerous lesions in the proximal and distal sections of the large intestine.

Occurrence of colorectal aberrant crypt foci depending on age and dietary patterns of patients

Background

Aberrant crypt foci (ACF) are commonly considered the early pre-cancerous lesions that can progress to colorectal cancer (CRC). The available literature data reveal that age, dietary factors and lifestyle can affect the development of several dozen percentages of malignant tumours, including CRC. In the present study, an attempt was made to assess the incidence and growth dynamics of ACF and to determine whether the type of diet affected the development and number of AFC.

Methods

Colonoscopy combined with rectal mucosa staining with 0.25% methylene blue was performed in 131 patients. On the day of examination, each patient completed a questionnaire regarding epidemiological data. According to their numbers, colorectal ACF were divided into three groups. The findings were analysed statistically. The Student’s t test and the U test were applied in order to determine the significance of differences of means and frequency of events in both groups. Statistica 7.1 and Excel 2010 were used.

Results

The single ACF occur in the youngest individuals (ACF < 5). Since the age of 38 years, the number of ACF gradually increases to show a decreasing tendency since the age of 60 years. The number of 5 < ACF < 10 occurs slightly later, since the age of 50 years, and dynamically increases reaching the maximum at the age of 62 years, subsequently the increase is proportional. ACF > 10 occur at a more advanced age (55 years) and their number gradually increases with age. The maximum number is observed at the age of 77 years.

In individuals not using high-fibre diets and with high intake of red meat, the probability of higher numbers of ACF increases. The probability of higher numbers of ACF (5 < ACF10) was observed in patients with colon diverticula. In patients with higher BMI, the number of ACF is higher.

Conclusion

Age significantly affects the number of colorectal ACF. The types of foods consumed can considerably increase the risk of colorectal ACF, which is particularly visible in individuals who do not regularly use high-fibre diets, those obese and with colon diverticula.

Co-administration of a probiotic strain Lactobacillus plantarum LS/07 CCM7766 with prebiotic inulin alleviates the intestinal inflammation in rats exposed to N,N-dimethylhydrazine

The aim of this study was to determine the anti-inflammatory effects of preventive administration of a probiotic strain Lactobacillus plantarum LS/07 CCM7766 alone or in combination with prebiotic inulin or with flax-seed oil in the gut of rats, which developed chronic inflammation following administration of the pro-carcinogen N,N-dimethylhydrazine (DMH). After 28weeks administration of probiotic/prebiotic-containing diet, rats were killed and their colons were examined by immunohistological criteria, whereas cytokines were determined in the jejunal mucosa. Application of DMH triggered the production of pro-inflammatory cytokines IL-2, IL-6, IL-17, and TNF-α, expression of pro-inflammatory mediators NF-κB, COX-2 and iNOS and caused depletion of goblet cells. Supplementing the diet with L. plantarum and its combination with the prebiotic abolished DMH-induced inflammatory process in the jejunal mucosa by inhibiting the production of pro-inflammatory cytokines and by stimulation of anti-inflammatory IL-10 cytokine synthesis, whereas concentration of TGF-β1 was not influenced significantly. Diet prevented a decrease in goblet cell numbers but numbers of mast cells were lowered only moderately. However, combined treatment of rats with L. plantarum and flax-seed oil had no significant effect on the parameters examined, except for decreased expression of NF-κB, in comparison with the negative control. Results indicate that the preventive administration of probiotic L. plantarum LS/07 CCM7766 alone or in combination with prebiotic inulin to rats with DMH-induced chronic inflammation can reduce inflammatory process in the jejunal and colon mucosa, probably indirectly, and involves down-regulation of synthesis of pro-inflammatory cytokines and suppression of NF-κB activity in mucosal cells.

Predictive value of rectal aberrant crypt foci for intraepithelial neoplasia in ulcerative colitis - a cross-sectional study

BACKGROUND

Ulcerative colitis (UC) is associated with an increased risk of colorectal cancer (CRC). Aberrant crypt foci (ACF) are important biomarkers of sporadic CRC risk. Their correlation with the risk of intraepithelial neoplasia (IN) in UC remains unclear.

AIMS

To assess whether ACF are a risk factor for IN in long-standing UC and to investigate any correlation between the clinico-epidemiological characteristics and prevalence/number of ACF in these patients.

METHODS

Seventy-six patients with long-standing UC were prospectively screened by colonoscopy with chromoendoscopy-guided endomicroscopy. ACF were sought in the lower rectum.

RESULTS

Eight INs were detected in seven (9.2%) patients. The ACF prevalence and mean number were 60.5% and 2.4 ± 2.8, respectively. The number of ACF was independently associated with the risk of having IN (odds ratio = 1.338; 95% confidence interval 1.030-1.738). ACF number revealed a good calibration (area under the receiver operating characteristic curve = 0.829) and discriminative ability (p = 0.205, Hosmer-Lemeshow test) for the prediction of synchronous IN. Patients with ≥3 ACF have a significantly higher prevalence of IN than patients with <3 ACF (22.6% vs. 0%, p = 0.001). Using this cut-off value, the performance of ACF in predicting the presence of IN was as follows: sensitivity = 100%, specificity = 65.2%, positive predictive value = 22.6%, and negative predictive value = 100%. Age >40 years, family history of CRC, and increased body mass index (BMI) were associated with a significantly higher number of ACF.

CONCLUSION

Long-standing UC patients with ≥3 ACF have a significantly higher likelihood of having IN. Age >40 years, family history of CRC, and increased BMI have significant positive associations with the number of ACF.

Evaluation of blueberry juice in mouse azoxymethane-induced aberrant crypts and oxidative damage

Blueberry is a plant with a number of nutritional and biomedical capabilities. In the present study we initially evaluated the capacity of its juice (BJ) to inhibit the number of aberrant crypts (AC) induced with azoxymethane (AOM) in mouse. BJ was administered daily by the oral route to three groups of animals during four weeks (1.6, 4.1, and 15.0 μL/g), respectively, while AOM (10 mg/kg) was intraperitoneally injected to the mentioned groups, twice a week, in weeks two and three of the assay. We also included two control groups of mice, one administered distilled water and the other the high dose of BJ. A significant increase of AC was observed in the AOM treated animals, and a mean protection of 75.6% was determined with the two low doses of BJ tested; however, the high dose of the juice administered together with AOM increased the number of crypts more than four times the value observed in animals administered only AOM. Furthermore, we determined the antioxidant potential of BJ with an ex vivo DPPH assay and found a dose-dependent decrease with a mean of 19.5%. We also determined the DNA oxidation/antioxidation by identifying 8-hydroxy-2'-deoxyguanosine adducts and found a mean decrease of 44.3% with the BJ administration with respect to the level induced by AOM. Our results show a complex differential effect of BJ related to the tested doses, opening the need to further evaluate a number of factors so as to determine the possibility of a cocarcinogenic potential.

Sequential Changes in Aberrant Crypt Foci and Lectin Expression in the Early and Late Stages of DMH-Induced Colon Carcinogenesis in Rats

BACKGROUND/AIMS

The purpose of this study was to investigate the malignant potential of aberrant crypt foci (ACF) by measuring the multiplicity of crypts and lectin expression in the early and late stages of 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis.

METHODS

Six-week-old Wistar rats were injected subcutaneously with DMH for 27 weeks. We classified ACF according to the number of crypts per ACF as a few crypts (≤3 crypts, FC ACF) or numerous crypts (≥4 crypts, NC ACF). Immunohistochemistry was used to evaluate lectin expression.

RESULTS

In the early stage, FC ACF (590/1,902, 31.0%) occurred more frequently than NC ACF (35/449, 7.8%); whereas in the late stage, NC ACF (176/449, 39.2%) occurred more frequently than FC ACF (324/1,902, 17.0%). The number of ACF peaked at 15 to 20 weeks. The ratio of NC/FC ACF increased gradually during carcinogenesis. The expression of both UEA1 and PNA was higher in NC ACF than FC ACF. Lectin expression increased in the late stage compared with the early stage.

CONCLUSIONS

The expression of lectin was higher in NC ACF and ACF in the late stage. Therefore, ACF with higher multiplicities in the late stage may have more malignant potential in DMH-induced colon carcinogenesis.

Phase IIa clinical trial of curcumin for the prevention of colorectal neoplasia

Curcumin is derived from the spice tumeric and has antiinflammatory and antineoplastic effects in vitro and in animal models, including preventing aberrant crypt foci (ACF) and adenomas in murine models of colorectal carcinogenesis. Inhibiting the production of the procarcinogenic eicosanoids prostaglandin E₂ (PGE₂) and 5-hydroxyeicosatetraenoic acid (5-HETE) can suppress carcinogenesis in rodents. Curcumin reduces mucosal concentrations of PGE₂ (via inhibition of cyclooxygenases 1 and 2) and 5-HETE (via inhibition of 5-lipoxygenase) in rats. Although preclinical data support curcumin activity in many sites, the poor bioavailability reported for this agent supports its use in the colorectum. We assessed the effects of oral curcumin (2 g or 4 g per day for 30 days) on PGE₂ within ACF (primary endpoint), 5-HETE, ACF number, and proliferation in a nonrandomized, open-label clinical trial in 44 eligible smokers with eight or more ACF on screening colonoscopy. We assessed pre- and posttreatment concentrations of PGE₂ and 5-HETE by liquid chromatography tandem mass spectroscopy in ACF and normal-tissue biopsies; ACF number via rectal endoscopy; proliferation by Ki-67 immunohistochemistry; and curcumin concentrations by high-performance liquid chromatography in serum and rectal mucosal samples. Forty-one subjects completed the study. Neither dose of curcumin reduced PGE₂ or 5-HETE within ACF or normal mucosa or reduced Ki-67 in normal mucosa. A significant 40% reduction in ACF number occurred with the 4-g dose (P < 0.005), whereas ACF were not reduced in the 2-g group. The ACF reduction in the 4-g group was associated with a significant, five-fold increase in posttreatment plasma curcumin/conjugate levels (versus pretreatment; P = 0.009). Curcumin was well tolerated at both 2 g and 4 g. Our data suggest that curcumin can decrease ACF number, and this is potentially mediated by curcumin conjugates delivered systemically.

Altered expression of apoptosis biomarkers in human colorectal microadenomas

Human colorectal microadenomas are considered the earliest detectable premalignant lesions in the colon. They can be identified as aggregates of enlarged crypts with thicker epithelial linings and elongated luminal openings on the colonic mucosal surface after methylene blue staining and observation under a dissecting microscope. Multiple lines of evidence suggest that a central role in neoplastic development is played by the inhibition of apoptosis, followed by disruption of DNA repair. Understanding the early mechanisms of colorectal carcinogenesis may help develop new approaches of colorectal cancer prevention and treatment. The aim of the present study was to quantify poly-ADP ribose polymerase 1 (PARP-1)-positive cells and to evaluate apoptotic control mechanisms through Caspase-3 active and Bcl-2 protein expression in human microadenomas and in normal colorectal mucosa using immunofluorescence techniques coupled with confocal microscopy and immunoblot experiments. The mean percentage of PARP-1-positive epithelial cells was 3.0 +/- 0.37% (SD) and 15.67 +/- 0.40% in microadenoma and in normal mucosa, respectively. Proteins involved in programmed cell death were differently expressed in microadenoma and in normal mucosa. Indeed, by semiquantitative immunofluorescence analysis, confirmed by Western blot, microadenoma showed low levels of Caspase-3 active and high levels of Bcl-2 expression, whereas the opposite was true for normal colorectal mucosa [corrected]. In the stroma of normal colorectal mucosa, fibroblast-like cells and neutrophils were the cells that underwent apoptosis to a greater extent. In conclusion, malfunction of the control mechanisms of programmed cell death seems present in the early stages of colorectal cancer development.