Nils Homann

Response of refractory colitis to intravenous or oral tacrolimus (FK506)

Intravenous cyclosporine has proven to be an alternative to emergency colectomy in steroid-refractory ulcerative colitis, whereas the experience with FK506 is limited. In this report we compare intravenous to oral FK506 treatment in 38 patients with refractory ulcerative (n = 33) or indeterminate (n = 5) colitis. FK506 was started intravenously in the first group (n = 18) at a dose of 0.01 to 0.02 mg/kg up to 14 days, followed by 0.1 to 0.2 mg/kg orally, or was started orally at this dose in a second group (n = 20). Additional azathioprine/6-mercaptopurine was given and steroids were tapered in responding patients, followed by a dose reduction of FK506. Clinical disease activity and laboratory parameters were assessed to evaluate efficacy and safety. Primary objectives were the induction of remission (Truelove index of mild) and colectomy-free survival. Treatment lasted for a mean of 7.6 months, and the mean observation period was 16.2 months. Eighteen of 38 patients improved within 14 days, and a complete remission was achieved in 13 patients after 1 month. A colectomy within 1 month was performed in 3 of 38 patients. The overall colectomy rate was 34%. One-half of the patients with a minimum follow-up of 2 years required a colectomy. Intravenous and per oral administration were equally safe and effective. The most frequent adverse events included tremor, hyperglycemia, hypertension, and infection, but none were severe. Renal impairment was rare and subsided upon drug withdrawal. In conclusion, FK506 is effective in the treatment of refractory colitis with per oral dosing being equivalent to intravenous administration.

Alcohol dehydrogenase 1C*1 allele is a genetic marker for alcohol‐associated cancer in heavy drinkers

Chronic alcohol consumption is associated with an increased risk for upper aerodigestive tract cancer and hepatocellular carcinoma. Increased acetaldehyde production via alcohol dehydrogenase (ADH) has been implicated in the pathogenesis. The allele ADH1C*1 of ADH1C encodes for an enzyme with a high capacity to generate acetaldehyde. So far, the association between the ADH1C*1 allele and alcohol‐related cancers among heavy drinkers is controversial. ADH1C genotypes were determined by polymerase chain reaction and restriction fragment length polymorphism in a total of 818 patients with alcohol‐associated esophageal (n = 123), head and neck (n = 84) and hepatocellular cancer (n = 86) as well as in patients with alcoholic pancreatitis (n = 117), alcoholic liver cirrhosis (n = 217), combined liver cirrhosis and pancreatitis (n = 17) and in alcoholics without gastrointestinal organ damage (n = 174). The ADH1C*1 allele and genotype ADH1C*1/1 were significantly more frequent in patients with alcohol‐related cancers than that in individuals with nonmalignant alcohol‐related organ damage. Using multivariate analysis, ADH1C*1 allele frequency and rate of homozygosity were significantly associated with an increased risk for alcohol‐related cancers (p<0.001 in all instances). The odds ratio for genotype ADH1C*1/1 regarding the development of esophageal, hepatocellular and head and neck cancer were 2.93 (CI, 1.84–4.67), 3.56 (CI, 1.33–9.53) and 2.2 (CI, 1.11–4.36), respectively. The data identify genotype ADH1C*1/1 as an independent risk factor for the development of alcohol‐associated tumors among heavy drinkers, indicating a genetic predisposition of individuals carrying this genotype.

Pathogenetic mechanisms of upper aerodigestive tract cancer in alcoholics

Chronic excessive alcohol consumption is the strongest risk factor for upper aerodigestive tract (UADT) cancer (oral cavity, pharynx, hypopharynx, larynx, esophagus).1 In addition, alcohol also increases the risk for cancer of the liver, colorectum and breast.1 A great number of epidemiological studies have demonstrated a correlation between alcohol ingestion and the occurrence of cancer in these organs.1–9 These studies clearly show that the ingestion of all types of alcoholic beverages is associated with an increased cancer risk that suggests that ethanol itself is the crucial compound that causes that effect. The exact mechanism(s) of ethanol-associated carcinogenesis has remained obscure because ethanol by itself when given to animals is not carcinogenic.10 Multiple mechanisms are involved in alcohol-associated cancer development of the UADT including the effect of acetaldehyde (AA), the first metabolite of ethanol oxidation, induction of cytochrome P-4502E1 (CYP2E1) leading to the generation of reactive oxygen species (ROS) and enhanced procarcinogen activation, modulation of cellular regeneration and nutritional deficiencies. In our minireview, major emphasis is laid on more recent developments including genetic aspects of ethanol metabolism, bacterial alcohol oxidation and nutritional deficiencies.

Ethanol‐mediated carcinogenesis in the human esophagus implicates CYP2E1 induction and the generation of carcinogenic DNA‐lesions

Chronic alcohol consumption is a major risk factor for esophageal cancer. Various mechanisms may mediate carcinogenesis including the genotoxic effect of acetaldehyde and oxidative stress. Ethanol exerts its carcinogenic effect in the liver among others via the induction of cytochrome P450 2E1 (CYP2E1) and the generation of carcinogenic etheno‐DNA adducts. Here we investigated if such effects can also be observed in the human esophagus. We studied nontumorous esophageal biopsies of 37 patients with upper aerodigestive tract cancer and alcohol consumption of 102.3 ± 131.4 g/day (range: 15–600 g) as well as 16 controls without tumors (12 teetotalers and 4 subjects with a maximum of 25 g ethanol/day). CYP2E1, etheno‐DNA adducts and Ki67 as a marker for cell proliferation were determined immunohistologically. Chronic alcohol ingestion resulted in a significant induction of CYP2E1 (p = 0.015) which correlated with the amount of alcohol consumed (r = 0.6, p < 0.001). Furthermore, a significant correlation between CYP2E1 and the generation of the carcinogenic exocyclic etheno‐DNA adducts 1,N6‐ethenodeoxyadenosine (r = 0.93, p < 0.001) and 3,N4‐ethenodeoxycytidine (r = 0.92, p < 0.001) was observed. Etheno‐DNA adducts also correlated significantly with cell proliferation (p < 0.01), which was especially enhanced in patients who both drank and smoked (p < 0.001). Nonsmokers and nondrinkers had the lowest rate of cell proliferation, CYP2E1 expression and DNA lesions. Our data demonstrate for the first time an induction of CYP2E1 in the esophageal mucosa by ethanol in a dose dependent manner in man and may explain, at least in part, the generation of carcinogenic DNA lesions in this target organ.

Evaluation of the transforming growth factor β1 codon 25 (Arg → Pro) polymorphism in alcoholic liver disease

INTRODUCTIONnLiver cirrhosis develops only in a minority of heavy drinkers. Genetic factors may account for some variation in the progression of fibrosis in alcoholic liver disease (ALD). Transforming growth factor beta 1 (TGFbeta1) is a key profibrogenic cytokine in fibrosis and its gene contains several polymorphic sites. A single nucleotide polymorphism at codon 25 has been suggested to affect fibrosis progression in patients with chronic hepatitis C virus infection, fatty liver disease, and hereditary hemochromatosis. Its contribution to the progression of ALD has not been investigated sufficiently so far.nnnPATIENTS AND METHODSnOne-hundred-and-fifty-one heavy drinkers without apparent ALD, 149 individuals with alcoholic cirrhosis, and 220 alcoholic cirrhotics who underwent liver transplantation (LTX) were genotyped for TGFbeta1 codon 25 variants.nnnRESULTSnUnivariate analysis suggested that genotypes Arg/Pro or Pro/Pro are associated with decompensated liver cirrhosis requiring LTX. However, after adjusting for patients age these genotypes did not confer a significant risk for cirrhosis requiring LTX.nnnCONCLUSIONnTGFbeta1 codon 25 genotypes Arg/Pro or Pro/Pro are not associated with alcoholic liver cirrhosis. Our study emphasizes the need for adequate statistical methods and accurate study design when evaluating the contribution of genetic variants to the course of chronic liver diseases.

Aneuploidy-associated gene expression signatures characterize malignant transformation in ulcerative colitis.

Background:Malignant transformation in ulcerative colitis (UC) is associated with pronounced chromosomal instability, reflected by aneuploidy. Although aneuploidy can precede primary cancer diagnosis in UC for more than a decade, little is known of its cellular consequences. Methods:Whole-genome gene expression analysis was applied to noninflamed colon mucosa, mucosal biopsies of patients with UC, and UC-associated carcinomas (UCCs). DNA image cytometry was used to stratify samples into ploidy types. Differentially expressed genes (DEGs) were analyzed by Ingenuity Pathway Analysis and validated by real-time quantitative PCR. Results:Gene expression changes were more pronounced between normal mucosa and UC (2587 DEGs) than between UC and UCC (827 DEGs). Cytometry identified colitis patients with euploid or aneuploid mucosa biopsies, whereas all UCCs were aneuploid. However, 1749 DEGs distinguished euploid UC and UCCs, whereas only 15 DEGs differentiated aneuploid UC and UCCs. A total of 16 genes were differentially expressed throughout the whole sequence from normal controls to UCCs. Particularly, genes pivotal for chromosome segregation (e.g., SMC3 and NUF2) were differentially regulated along aneuploidy development. Conclusions:The high number of DEGs between normal mucosa and colitis is dominated by inflammatory-associated genes. Subsequent acquisition of aneuploidy leads to subtle but distinct transcriptional alterations, revealing novel target genes that drive genomic instability and thus carcinogenesis. The gene expression signature of malignant phenotypes in aneuploid UC suggests that these lesions might need to be considered as severe as high-grade dysplasia.

Serumtest für C3a Anaphylatoxin ermöglicht minimal-invasives Screening für kolorektale Tumoren

Background: Late diagnosis of colorectal carcinomas results in a significant reduction of average survival times. However, despite screening programs, about 70 % of tumors are detected at advanced stages (UICC III/IV). We therefore aimed at detecting tumor-specific protein biomarkers in serum samples that could potentially be applied for early diagnostics. Methods: A discovery set of sera from patients with colorectal malignancy (n = 58) and healthy control individuals (n = 32) were evaluated for potential differences using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF). Candidate markers were identified and validated using enzyme-linked immunosorbent assays (ELISA). Results: Several m/z values were expressed differentially between malignant and healthy control samples of the discovery set. Identification of the most prominent m/z value revealed C3a anaphylatoxin (C3a-desArg). ELISA based C3a-levels allowed correct classification of serum samples within the blinded validation set with 96 % sensitivity and specificity. Increased serum levels detected also 86 % of an independent sera (n = 36) set from patients with colorectal adenomas. Conclusions: Increased serum levels of C3a-desArg allowed correct group classification of patients with colorectal adenomas and carcinomas with high sensitivity and specificity (both 96 %, p < 0.0001). C3a-desArg serum level assessment could thus ameliorate existing screening tests for colorectal cancer.