Cardiac autonomic modulation induced by doxorubicin in a rodent model of colorectal cancer and the influence of fullerenol pretreatment.

The very effective anticancer drug doxorubicin (DOX) is known to have cardiotoxic side effects, which could be accompanied by autonomic modulation. Autonomic disbalance might even be an initiating mechanism underlying DOX-induced cardiotoxicity and can be studied noninvasively by the analysis of heart rate variability (HRV). A number of strategies have been assessed to predict chemotherapy-induced cardiac dysfunction while HRV, a potential detecting tool, has not yet been tested. Thus, we aimed to determine the effect of DOX treatment on HRV in a rat model of colorectal cancer. While pretreatment with fullerenol (Frl) acts protectively on DOX-induced cardiotoxicity, we aimed to test the effect of Frl pretreatment on DOX-induced HRV alterations. After the induction of colorectal cancer, adult male Wistar rats were treated with saline (n = 7), DOX (1.5 mg/kg per week, n = 7) or DOX after pretreatment with Frl (25 mg/kg per week, n = 7) for three weeks (cumulative DOX dose 4.5 mg/kg). One week after treatment rats were anaesthetized, standard ECG was measured and HRV was analyzed in time and frequency domain. During autopsy the intestines and hearts were gathered for biochemical analysis and histopathological examination. DOX treatment significantly decreased parasympathetically mediated high-frequency component (p<0.05) and increased the low-frequency component of HRV (p<0.05), resulting in an increased LF/HF ratio (p<0.05) in cancerous rats. When pretreated with Frl, DOX-induced HRV alterations were prevented: the high-frequency component of HRV increased (p<0.01), the low-frequency decreased (p<0.01), LF/HF ratio decreased consequently (p<0.01) compared to DOX only treatment. In all DOX-treated animals, disbalance of oxidative status in heart tissue and early myocardial lesions were found and were significantly reduced in rats receiving Frl pretreatment. Autonomic modulation accompanied the development of DOX-induced cardiotoxicity in rat model of colorectal cancer and was prevented by Frl pretreatment. Our results demonstrated the positive prognostic power of HRV for the early detection of DOX-induced cardiotoxicity.

Dextran sulphate sodium colitis in C57BL/6J mice is alleviated by Lactococcus lactis and worsened by the neutralization of Tumor necrosis Factor α.

TNFα has a well-established role in inflammatory bowel disease that affects the gastrointestinal tract and is usually manifested as Crohn's disease or ulcerative colitis. We have compared Lactococcus lactis NZ9000 displaying TNFα-binding affibody with control Lactococcus lactis and with anti-TNFα antibody infliximab for the treatment of mice with dextran sulphate sodium (DSS)-induced colitis. L. lactis NZ9000 alleviated the colitis severity one week after colitis induction with DSS, more effectively when administered in preventive fashion prior to, during and after DSS administration. TNFα-binding L. lactis was less effective than control L. lactis, particularly when TNFα-binding L. lactis was administered in preventive fashion. Similarly, an apparently detrimental effect of TNFα neutralization was observed in mice that were intraperitoneally administered anti-TNFα monoclonal antibody infliximab prior to colitis induction. The highest concentrations of tissue TNFα were observed in groups without DSS colitis that were treated either with TNFα-binding L. lactis or infliximab. To conclude, we have confirmed that L. lactis exerts a protective effect on DSS-induced colitis in mice. Contrary to expectations, but in line with some reports, the neutralization of TNFα aggravated disease symptoms in the acute phase of colitis and increased TNFα concentration in colon tissue of healthy mice. Nevertheless, we have demonstrated that oral administration of bacteria with surface displayed TNFα-binding affibody can interfere significantly with TNFα signaling and mimic the infliximab response in the given animal model of colitis.

Improved Protective Effect of Umbilical Cord Stem Cell Transplantation on Cisplatin-Induced Kidney Injury in Mice Pretreated with Antithymocyte Globulin.

Mesenchymal stem cells (MSCs) are recognised as a promising tool to improve renal recovery in experimental models of cisplatin-induced acute kidney injury. However, these preclinical studies were performed on severely immunodeficient animals. Here, we investigated whether human umbilical cord derived MSC treatment could equally ameliorate acute kidney injury induced by cisplatin and prolong survival in mice with a normal immune system and those with a suppressed immune system by polyclonal antithymocyte globulin (ATG). We demonstrated that ATG pretreatment, when followed by MSC transplantation, significantly improved injured renal function parameters, as evidenced by decreased blood urea nitrogen and serum creatinine concentration, as well as improved renal morphology. This tissue restoration was also supported by increased survival of mice. The beneficial effects of ATG were associated with reduced level of inflammatory protein serum amyloid A3 and induced antioxidative expression of superoxide dismutase-1 (SOD-1), glutathione peroxidase (GPx), and hem oxygenase-1 (HO-1). Infused MSCs became localised predominantly in peritubular areas and acted to reduce renal cell death. In conclusion, these results show that ATG diminished in situ inflammation and oxidative stress associated with cisplatin-induced acute kidney injury, the effects that may provide more favourable microenvironment for MSC action, with consequential synergistic improvements in renal injury and animal survival as compared to MSC treatment alone.

Dextran sodium sulphate colitis mouse model: traps and tricks.

Inflammatory bowel disease (IBD) is a complex multifactorial disease of unknown etiology. Thus, dozens of different animal models of IBD have been developed in past decades. Animal models of IBD are valuable and indispensable tools that provide a wide range of options for investigating involvement of various factors into the pathogenesis of IBD and to evaluate different therapeutic options. However, the dextran sulphate sodium (DSS-) induced colitis model has some advantages when compared to other animal models of colitis. It is well appreciated and widely used model of inflammatory bowel disease because of its simplicity. It has many similarities to human IBD, which are mentioned in the paper. In spite of its simplicity and wide applicability, there are also traps that need to be taken into account when using DSS model. As demonstrated in the present paper, various factors may affect susceptibility to DSS-induced lesions and modify results.

Morphological and molecular alterations in 1,2 dimethylhydrazine and azoxymethane induced colon carcinogenesis in rats.

The dimethyhydrazine (DMH) or azoxymethane (AOM) model is a well-established, well-appreciated, and widely used model of experimental colon carcinogenesis. It has many morphological as well as molecular similarities to human sporadic colorectal cancer (CC), which are summarized and discussed in this paper. In addition, the paper combines present knowledge of morphological and molecular features in the multistep development of CC recognized in the DMH/AOM rat model. This understanding is necessary in order to accurately identify and interpret alterations that occur in the colonic mucosa when evaluating natural or pharmacological compounds in DMH/AOM rat colon carcinogenesis. The DMH/AOM model provides a wide range of options for investigating various initiating and environmental factors, the role of specific dietary and genetic factors, and therapeutic options in CC. The limitations of this model and suggested areas in which more research is required are also discussed.

Effects of high-fat mixed-lipid diet and exercise on the antioxidant system in skeletal and cardiac muscles of rats with colon carcinoma.

Epidemiological and experimental studies suggest that eating habits and a sedentary lifestyle play a critical role in the incidence of colon carcinoma. In order to investigate the effects of high-fat mixed-lipid (HFML) diet in conjunction with long-term swimming, the antioxidant capacity of skeletal and cardiac muscles were observed in rats with 1,2-dimethylhydrazine (DMH)-induced colon carcinoma. Male Wistar rats were randomly divided into one control group and four cancer groups: sedentary and swimming groups fed low fat corn oil diet and sedentary and swimming groups, fed a HFML diet. After 6 months of swimming, rats were sacrificed and the blood, cardiac and soleus muscle were taken for analysis. Serum cholesterol, triglyceride and glucose concentrations were measured and the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase as well as levels of malondialdehyde and glutathione were determined. The results showed that endurance swimming prevented lipid peroxidation in the soleus muscle of HFML diet rats due to elevated activities of antioxidant enzymes. On the other hand, increased lipid peroxidation in the hearts of all cancer groups indicated that DMH-induced colon carcinoma impaired the antioxidant status of the heart. This failure in heart tissue indicated that enhanced antioxidant capacity after regular physical activity is not sufficient to offset oxidative stress caused by DMH-induced colon carcinoma.

Acute doxorubicin pulmotoxicity in rats with malignant neoplasm is effectively treated with fullerenol C60(OH)24 through inhibition of oxidative stress.

The aim of this study was to investigate the possible protective role of fullerenol (FLR, C(60)(OH)(24) on doxorubicin (DOX)-induced lung toxicity using biochemical and histopathological approaches. Rats (Sprague-Dawley outbred) were randomly divided into five groups. The healthy control group received no medication (saline only). The other four groups had chemically induced breast cancer (1-methyl-1-nitrosourea; 50 mg/kg, ip). The second group was the cancer control group (saline only). The other three groups were DOX (8 mg/kg, ip), FLR/DOX (100 mg/kg, ip, 30 min before DOX; 8 mg/kg, ip), and FLR (100 mg/kg, ip), respectively. The levels of malondialdehyde (MDA) and oxidized glutathione (GSSG) in the lung tissue were higher in the group treated with DOX alone than in the control groups. The activities of catalase (CAT), glutathione reductase (GR), superoxide dismutase (SOD), and lactate dehydrogenase (LDH) were found to be increased in the lung tissue of the animals in the DOX group over all the other groups, while GSH-Px significantly decreased in activity compared with the control and FLR groups. There was no significant difference in MDA and GSSG levels and enzyme activities in either control (healthy; cancer) or FLR (FLR/DOX; FLR) groups. The acute change found in the DOX group was subpleural edema. In contrast, the groups treated with FLR appeared to be virtually histopathologically normal. In conclusion, this study clearly indicates that DOX treatment markedly impairs pulmonary function and that pre-treatment with FLR might prevent this toxicity in rats through inhibition of oxidative stress.

Protective effects of fullerenol C60(OH)24 against doxorubicin-induced cardiotoxicity and hepatotoxicity in rats with colorectal cancer.

The effects of fullerenol C60(OH)24 (Frl) at doses of 25, 50, and 100mg/kg/week (for a time-span of 3 weeks) on heart and liver tissue after doxorubicin (Dox)-induced toxicity in rats with colorectal cancer were investigated. In the present study, we used an in vivo Wistar male rat model to explore whether Frl could protect against Dox-induced (1.5mg/kg/week for 3 weeks) chronic cardio- and hepato- toxicity and compared the effect with a well-known antioxidant, vitamin C (100mg/kg/week for 3 weeks). According to macroscopic, microscopic, hematological, biochemical, physiological, pharmacological, and pharmacokinetic results, we confirmed that, at all examined doses, Frl exhibits a protective influence on the heart and liver tissue against chronic toxicity induced by Dox.

Acute doxorubicin nephrotoxicity in rats with malignant neoplasm can be successfully treated with fullerenol C60(OH)24 via suppression of oxidative stress.

Oxidative stress has an important role in the pathogenesis of doxorubicin (DOX)-induced nephrotoxicity. The aim of this study was to investigate the nephroprotective effects of fullerenol (FLR), an antioxidant agent, on DOX-induced nephrotoxicity. The investigation was carried out on adult female Sprague Dawley outbred rats with chemically induced breast cancer (1-methyl-1-nitrosourea; 50 mg/kg; ip). Rats were divided into the following groups: control healthy, control cancer, DOX alone (8 mg/kg, ip, cancer), DOX plus FLR as a pre-treatment (8 mg/kg and 100 mg/kg, respectively, ip, cancer), and FLR alone (100 mg/kg, ip, cancer). At the end of the 2nd day after drug administration, blood and kidney tissues were taken for analysis. The activity of lactate dehydrogenase and alpha-hydroxybutyrate dehydrogenase as serum enzymes, as well as level of malondialdehyde, glutathione, glutathione peroxidase, glutathione reductases, catalase and superoxide dismutase, were determined. DOX caused nephrotoxicity, but FLR pre-treatment prevented oxidative stress, lipid peroxidation and the disbalance of GSH/GSSG levels in kidney tissue caused by DOX. Our results confirm satisfactory nephroprotective efficacy of FLR in the acute phase of toxicity and encourage further studies regarding its use as a potential nephroprotector.

Potential hepatoprotective effects of fullerenol C60(OH)24 in doxorubicin-induced hepatotoxicity in rats with mammary carcinomas.

The aim of this study was to investigate the potential protective role of fullerenol C60(OH)24 on doxorubicin-induced liver toxicity using in vivo (female Sprague-Dawley rats) and in vitro (human hepatocellular carcinoma - HepG2; colorectal adenocarcinoma cell lines - Caco-2) approaches. The first (healthy control) and second (control with chemically induced mammary carcinomas) group received saline only. The third, fourth and fifth group (all with breast cancer) were injected (i.p.) with a single dose of doxorubicin (8mg/kg), doxorubicin/fullerenol (100mg/kg of fullerenol 30min before administration of 8mg/kg doxorubicin) and fullerenol (100mg/kg), respectively. Two days after treatment, the rats were sacrificed. Results showed that treatment with doxorubicin alone caused significant changes in the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and alpha-hydroxybutyrate dehydrogenase (alpha-HBDH), as well as in the levels of malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase (GSH-Px), total antioxidant status (TAS), glutathione reductase (GR), catalase (CAT) and superoxide dismutase (SOD) in the liver tissue. These effects were significantly reduced for all investigated parameters by pre-treatment with fullerenol but not for the MDA and GSH level. The HepG2 and Caco-2 cell lines were continuously treated with fullerenol for 12h, 24h, 48h and 96h at concentrations of 10microg/mL and 44microg/mL. With the aim of evaluating the modulating activity of fullerenol on doxorubicin-induced hepatotoxicity, the cell lines were simultaneously treated with doxorubicin (1microm; 5microm) and fullerenol (10microg/mL; 44microg/mL) in different combinations. When the cells are treated with 5microm doxorubicin along with the fullerenol, we can see a significant improvement of the cell capability during the entire time-line. We can conclude that fullerenol has cytotoxic effects on HepG2 by itself, but when the oxidative stress is too high the cytotoxic effects of fullerenol are overcome by its protective role as a strong antioxidant compound.

Clinico-pathological aspects of colorectal serrated adenomas.

AIM: To study the association of colorectal serrated adenomas (SAs) with invasive carcinoma, local recurrence, synchronicity and metachronicity of lesions. METHODS: A total of 4,536 polyps from 1,096 patients over an eight-year period (1987-1995) were retrospectively examined. Adenomas showing at least 50% of serrated architecture were called SAs by three reviewing pathologists. RESULTS: Ninety-one (2%) of all polyps were called SAs, which were found in 46 patients. Invasive carcinomas were seen in 3 out of 46 (6.4%) patients, of whom one was a case of familial adenomatous polyposis (FAP). A male preponderance was noted and features of a mild degree of dysplasia were seen in majority (n=75, 83%) of serrated adenomas. Follow-up ranged 1-12 years with a mean time of 5.75 years. Recurrences of SAs were seen in 3 (6.4%) cases, synchronous SAs in 16 (34.8%) cases and metachronous SAs in 9 (19.6%) cases. CONCLUSION: Invasive carcinoma arising in serrated adenoma is rare, accounting for 2 (4.3%) cases studied in this series.

Rofecoxib does not inhibit aberrant crypt foci formation but inhibits later steps in the development of experimental colorectal cancer: rofecoxib in experimental colon cancer.

OBJECTIVE: Cyclooxygenase-2 (COX-2) has been shown to have an important role in carcinogenesis. Elevated COX-2 expression has been reported in several human tumours, including colorectal cancer (CRC) and appears to correlate with survival inversely. Regular use of non-steroidal anti-inflammatory drugs (NSAIDs) can decrease the incidence of CRC, but prolonged administration may cause side effects. Selective COX-2 inhibitors have comparable effects to NSAIDs with reduced side effects. The aim of the present study was to analyse the potential therapeutic role of rofecoxib, a selective COX-2 inhibitor, in experimentally induced rat colorectal tumours. MATERIAL AND METHODS: Sixty-three Wistar male rats (33 in the experimental group and 30 in the control group) received subcutaneous injections of 1,2-dimethylhydrazine (DMH). Synchronal with the first injection of DMH in the experimental group, rats were given rofecoxib orally for 6 months, when autopsy was done. Colorectal tumours were evaluated quantitatively and histopathologically for the presence of aberrant crypt foci (ACF), adenomas and adenocarcinomas. RESULTS: No statistically significant differences were found in the number of dysplastic ACF between the experimental and control groups (p > 0.05). However, a significant lower incidence of adenomas (p < 0.05), adenocarcinomas (p < 0.05) and decreased volume of macroscopically visible tumours (by 42%) was found in the experimental group. Furthermore, no significant differences were evaluated between the groups according to the degree of dysplasia and Dukes stage. In the experimental group, chronic ulcerations were found in the upper gastrointestinal tract in 9% of the rats. CONCLUSION: Our data suggest that rofecoxib effectively inhibits tumour growth and progression but not tumour initiation.

Colorectal carcinoma in endoscopic biopsies; additional histologic criteria for the diagnosis.

In endoscopic biopsies, desmoplastic stroma and/or tumor invasion of the submucosa are generally regarded as histologic features that allow for the diagnosis of colorectal carcinoma (CRC). They are not present in all endoscopic biopsies of CRC. We investigated tumor necrosis and invasion of adjacent normal mucosa for their usefulness as possible additional histologic criteria for CRC, and evaluated quantitatively the diagnostic reliability of each of the four aforementioned histologic features in routine biopsy practice. We analyzed 440 endoscopic biopsies of lesions endoscopically suspicious of CRC and compared them with 26 colorectal adenomas with malignant change and 344 colorectal adenomas. The slides were stained by H&E and the Kreyberg-Jareg trichrome method. The endoscopic histologic diagnoses were verified by histologic examination of surgically resected specimens. In endoscopic biopsies of CRC, desmoplastic stroma was found in 83.6% of the cases, tumor necrosis in 75.7%, submucosal invasion in 27.0%, and invasion of normal mucosa in 22.7%. When only one of the diagnostic features was present, there was a false positivity of 2.5-13.3%; however, the latter has fallen to 0.8% when two features were present, but disappeared when there were three or four histologic features. Adenomas with malignant change showed necrosis in 69.2% and invasion of adjacent mucosa in 15.3%. In adenomas, necrosis was present in 0.6% of the cases, desmoplastic stroma in 3.2%, and shallow erosions in 27.3%. The presence of tumor necrosis and invasion of normal mucosa were characteristic histologic features of CRC; therefore, they represent useful additional histologic criteria for the diagnosis of CRC in endoscopic biopsies. The reliability of the histologic diagnosis of CRC correlated with the number of the four aforementioned histologic features.

Animal model in the study of colorectal carcinogenesis.

Experimental animal models of neoplastic diseases are important in understanding etiological and pathophysiological processes also in humans. In order to investigate whether the mechanism of genomic instability is associated with chemically induced colorectal tumorigenesis in rat we performed the following study: One hundred and fifty Wistar rats (males 220-280 g and females 140-180 g) were used in the study. Colorectal tumors were induced by means of 15 s.c. applications (20 mg/kg) of 1,2-dimethylhydrazine (DMH). On autopsy, all intestinal lesions were assessed by histological criteria used in human pathology. Forty five tumors were found in the large intestine - 30 of these in males and 15 in females, i.e. in 27% of all animals. In four animals multiple primary tumors were found. Histologically 24 tumours were adenocarcinomas, 14 signet-cell carcinoma and 7 adenomas. DNA was extracted from rat neoplastic lesions and adjoining microscopically normal tissues from the same slide and amplified by PCR, using 10 different microsatellite markers from chromosomes 1, 3, 5, 7 and 8. PCR amplicon were analyzed for microsatellite instability with non-isotopic method. In 13 adenocarcinomas (29%) microsatellite instability was found at a minimum of 1 locus. Seven tumors (15.5%) showed microsatellite instability at multiple loci. The results of our experiment suggest that genomic instability is an important molecular event in the pathophysiology of DMH induced colorectal carcinogenesis in rats.