Chronic hepatitis C infection: An independent risk factor for subclinical atheromatosis. / Infección crónica por el virus de la hepatitis C: un factor de riesgo independiente para la ateromatosis subclínica.

BACKGROUND: The association between subclinical atheromatosis and chronic hepatitis C virus (HCV) infection is unknown but is relevant now that antivirals are improving the survival of patients with the infection. OBJECTIVES: To determine whether HCV is an independent risk factor for subclinical atheromatosis and to analyse the changes in lipid profiles according to viral RNA levels and hepatic fibrosis. PATIENTS AND METHODS: We conducted an observational, cross-sectional study that included 102 HCV-positive patients and 102 HCV-negative patients with parity in terms of sex and age, with no history of cardiovascular or kidney disease or diabetes. Atheromatosis (the presence of atheromatous plaques) and the carotid intima-media thickness (CIMT) were assessed using ultrasonography of the carotid and femoral arteries. RESULTS: There was a greater presence of atheromatosis in any vascular territory in HCV-positive patients than in the patients without infection (58.8% vs. 28.4%, p<.0001). In the multivariate analysis, the factors significantly associated with atheromatosis included HCV infection (OR, 14.37 [5.5-37.3]; p<.001), age (OR, 1.12 [1.1-1.2]; p<.001), male sex (OR, 4.32 [1.9-9.5]; p<.001) and the triglyceride/HDL cholesterol coefficient (TG/HDL-indirect indicator of insulin resistance) (OR, 1.34 [1.1-1.6]; p=.007). The HCV-positive patients with atheromatous plaques had a higher TG/HDL coefficient but no significant differences in terms of the viral load or degree of hepatic fibrosis and with a 'low risk' lipid profile. CONCLUSIONS: HCV infection is an independent risk factor for subclinical atheromatosis. Systemic arterial ultrasonography for this population improves the cardiovascular risk assessment beyond lipid profile abnormalities and the risk calculation using SCORE tables.

Telomeres and telomerase in the clinical management of colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer worldwide. Our aim is to describe the state of the art about the role of telomeres and telomerase in the clinical management of CRC and its potential utility as prognostic and diagnostic biomarkers and targets of new treatments. Telomere length could be a new diagnostic marker as an anomalous behavior is observed in peripheral blood cells when CRC patients and healthy people are compared. Moreover, telomeres and telomerase may be used as diagnostic markers considering that universal changes appear along the CRC process. Currently, new therapeutic cancer approaches are focused on inhibiting the maintenance of telomere length, choosing as targets telomerase -or its subunits- or the Shelterin complex. The goal of these therapies is the shortening of telomeres and the induction of cell senescence. Telomeres and telomerase emerge as useful molecular tools in the clinical management of CRC.

Telomeric repeat factor 1 protein levels correlates with telomere length in colorectal cancer.

BACKGROUND: colorectal cancer is the third cancer cause of death in Spain. It is important to investigate new tumoral markers for early diagnosis, disease monitoring and prevention strategies. Telomeres protect the chromosome from degradation by nucleases and endto-end fusion. The progressive loss of the telomeric ends of chromosomes is an important mechanism in the timing of human cellular aging. Telomeric Repeat Factor 1 (TRF1) is a protein that binds at telomere ends. PURPOSE: to measure the concentrations of TRF1 and the relationships among telomere length, telomerase activity, and TRF1 levels in tumor and normal colorectal mucosa. METHOD: from normal and tumoral samples of 83 patients who underwent surgery for colorectal cancer we analyzed TRF1 protein concentration by Western Blot, telomerase activity, by the fluorescent-telomeric repeat amplification protocol assay and telomere length by Southern Blot. RESULTS: high levels of TRF1 were observed in 68.7% of tumor samples, while the majority of normal samples (59%) showed negative or weak TRF1 concentrations. Among the tumor samples, telomere length was significantly associated with TRF1 protein levels (p = 0.023). CONCLUSIONS: a relationship was found between telomere length and TRF1 abundance protein in tumor samples, which means that TRF1 is an important factor in the tumor progression and maybe a diagnostic factor.

Telomerase activity and telomere length in the colorectal polyp-carcinoma sequence.

OBJECTIVE: The role of telomerase activity and telomere length in the adenoma-carcinoma sequence of colon carcinogenesis has not been well established. The objective of this study was to determine telomerase activity and telomere length patterns in patients with adenomatous polyps either associated or not with colorectal cancer, as well as the role of telomeric instability in the adenoma-carcinoma sequence. PATIENTS AND METHODS: We included in the study 14 patients who underwent surgery for colorectal cancer and/or polyps. In 6 of these patients fresh samples of tumor tissue, polyps, and normal mucosa were obtained; in the 8 remaining cases, we collected only polyps and normal mucosa. We used the fluorescent-telomeric repeat amplification protocol assay (TRAP-F) to determine telomerase activity and telomere length using Southern-blot testing. RESULTS: Telomerase activity was detected in 86% of polyps and 50% of associated normal mucosa. Mean telomerase activity in polyp tissue was 5.85; in the normal mucosa it was 0.58 TPG. Mean telomere length was 6.78 Kbp and 7.78, respectively. Polyps in patients without synchronous cancer had a telomerase activity that was significantly higher (9.4) than in those with cancer (1.1). CONCLUSIONS: Telomerase activity increases in the colorectal adenoma-carcinoma sequence, concurrently with a decrease in telomere length. The presence of synchronous cancer modifies telomerase activity in polyps.

[Effect of ursodeoxycholic acid in an experimental colon cancer model]. / Efecto del ácido ursodeoxicólico en un modelo experimental de cáncer de colon.

AIMS: The present study was designed to examine the effect of ursodeoxycholic acid as chemoprotective agent in experimental colon carcinogenesis in rats. MATERIAL AND METHODS: One hundred and ten 10-week-old, Sprague-Dawley rats were divided into five groups: group A (20), no treatment. Group B (20), receiving daily both ursodeoxycholic acid (UDCA) 4 mg/kg of body weight and ethanol 1.23 g/kg of body weight added to the drinking water from the beginning of the study through 24 weeks. Group C (30), receiving 18 weekly doses of dimethylhydrazine (DMH) 21 mg/kg of body weight subcutaneously from the beginning of the study, with the same doses of UDCA and ethanol as in group B. Group D (20), ethylen-diamin-tetracetic acid solution alone for 18 weeks. Group E (20), receiving the same doses of ethanol plus DMH injections as in group C. All experimental animals were sacrificed after 25-27 weeks. RESULTS: No tumors developed in dimethylhydrazine-free groups. No significant differences in number of tumor-free animals, number of tumors per rat, and macro-microscopic tumor findings were seen between animals in group C and animals in group E. CONCLUSIONS: We concluded that such an ursodeoxycholic acid supplementation did not modify colorectal carcinogenesis using a dynamic DMH-induced model in rats.

Effect of defunctionalization on colon carcinogenesis in the rat.

OBJECTIVE: to examine the effect of fecal absence on experimental colon carcinogenesis in both male and female rats. MATERIAL AND METHODS: a total of 138 10-week-old Sprague-Dawley, male and female rats were divided into five groups: A) 20 rats, no treatment; B) 26 rats, colonic defunctionalization; C) 30 rats, 18 weekly doses of dimethylhydrazine (DMH), 21 mg/kg body weight each, from the beginning of the study; D) 20 rats, ethylen-diamine-tetraacetic acid for 18 weeks; and E) 42 rats, same surgical procedure as rats in group B plus DMH injections at the same doses as rats in group C. Animals were sacrificed after 25-27 weeks. Number of tumors, their location, and pathological findings were all compared between groups. RESULTS: no tumors developed in the dimethylhydrazine-free groups. No differences were obtained either in number of tumors or tumors per rat for group C as compared to group E. Fecal absence was associated with smaller-sized tumors (p = 0.007), greater numbers of non-mucinous tumors (p = 0.00009), better differentiation (p = 0.0054), and lesser penetration into the wall (p = 0.015) for group E as compared to group C. In the dimethylhydrazine group, fecal absence altered the number of tumors developing in males as compared to female rats (p = 0.025). Moreover, this fecal absence showed no inhibitory effect on right colonic tumors (p = 0.0065). CONCLUSIONS: fecal absence alters the DMH-carcinogenic pattern in the defunctionalized colon when using an experimental model in both male and female rats.

Effect of ethanol consumption on colon cancer in an experimental model.

AIMS: The present study was designed to examine the effect of an ethanol supplement on experimental colon carcinogenesis. MATERIAL AND METHODS: One hundred and ten 10-week-old Sprague-Dawley rats were divided into five groups: group A (20 rats) received no treatment. Group B (20 rats) received a supplement of ethanol at 1.23 g/kg of body weight per day added to their drinking water for 24 weeks. Group C (30 rats) received 18 weekly doses of dimethylhydrazine (DMH) at 21 mg/kg of body weight from the beginning of the study. Group D (20 rats) received ethylen-diamin-tetracetic acid (EDTA) solution only for 18 weeks. Group E (20 rats) received ethanol at the same dose as group B plus DMH injections at the same dose as the rats in group C from the beginning of the study. All experimental animals were sacrificed after 25-27 weeks. RESULTS: No significant differences in the number of rats that developed tumors, number of tumor-free animals, and number of tumors per rat, as well as in macro-microscopic tumoral findings were observed for animals in group C compared to animals in group E. CONCLUSIONS: We concluded that the addition of an ethanol supplement does not modify colorectal carcinogenesis using a dynamic model of tumor induction with DMH.

Repetitive mucosal trauma promotes colon cancer in experimental rat model.

OBJECTIVE: To investigate the effect of repetitive mucosal trauma, anastomosis and intestinal content on experimental colonic carcinogenesis as there is the possibility than non-specific colon lesions can promote cancer. MATERIAL AND METHOD: We performed to sixty female Sprague-Dawley rats a 4 cm colon loop defunctionalization with double colostomy (traumatic site). Intestinal continuity was restored with an end-to-end colo-colic silk anastomosis. The surviving 47 rats were divided in 3 groups: Group A: 27 rats treated with DMH. Group B: 10 rats treated with EDTA and Group C: Control of 10 rats. Animals were sacrificed 31-32 weeks after surgery for macro and micropathological studies. RESULTS: In group A appeared 60 tumours: 44 in the functional colon, 20 of them in the anastomotic site; 8 in the non traumatised defunctionalized segment and 18 in the traumatised segment (p < 0.05). CONCLUSIONS: a) Continuous microtraumas on colonic mucosa in rats are cancer promotional factors; b) silk suture in anastomosis promotes cancer.

[Obstructive colitis: analysis of 7 patients]. / Colitis obstructiva: un análisis de 7 enfermos.

The term "obstructive colitis" is defined by the presence of ulcero-inflammatory lesions in a colonic area proximal to a potentially obstructive lesion. Seven cases retrospectively identified during a 5-year period are here reported. They illustrate the clinico-pathological spectrum of this entity. Most patients were women, with a mean age of 66 years and with history of chronic underlying disease (diabetes mellitus and arterial hypertension). Abdominal distension and pain, as well as acute constipation were the main clinical symptoms. An adenocarcinoma predominantly located at the rectosigmoidal region accounted for the obstructive nature in 100% of cases. Macroscopically the colitis area was moderately dilated and there were single or confluent ulcers in the luminal surface. Characteristically, there was always a transitional preserved area between the obstruction and the colitis area. Microscopically, the mucosa was totally replaced by a granulation tissue with a relevant inflammatory infiltrate involving up to the muscularis propria. The cytometric study revealed and increase in the cell cycle (S-phase) and proliferation index, at the level of the obstructive lesion, with marked aneuploidy in cases with advanced neoplastic invasion. The role of mural hypoperfusion with localized ischemia in the pathogenesis is discussed. The similarities with other colonic inflammatory diseases are emphasized.

Calcium inhibits colon carcinogenesis in an experimental model in the rat.

Different dietary factors can affect colorectal cancer incidence. However, the effect of increased levels of dietary calcium on neoplasms is unclear. The present study was designed to examine the effect of a low calcium supplement on experimental colon carcinogenesis induced by parenteral administration of dimethylhydrazine (DMH). One hundred and twenty 10-week-old Sprague-Dawley rats were divided into five groups of equal sex distribution. The 10 rats in group A (control group) received no treatment; the 30 rats in group B (DMH group) were injected subcutaneously with 18 weekly doses of 21 mg/kg DMH; the 20 rats in group C (EDTA control group) received EDTA solution only; the 30 rats in group D (calcium group) received calcium at 3.2 g/l by adding calcium lactate to the drinking water from the start until the conclusion of the experiment; and the 30 rats in group E (DMH + calcium group) received oral calcium supplements at the same dose as the rats in group D (calcium group) and the same DMH injections as the rats in group B (DMH group). The rats were sacrificed at 25-34 weeks. In group E, we observed a significant diminution in the number of tumours (P = 0.01); an increase in the number of tumour-free animals (P = 0.006); a change in tumour location towards the distal colon (P < 0.025); more adenomas (P = 0.02); and a diminution of adenocarcinomas and mucinous carcinomas, although this was not significant. We conclude that a low dietary calcium supplement in rats inhibits colon cancer carcinogenesis induced by DMH, and changes tumour location towards the distal colon.