Comprehensive analysis and ACMG-based classification of CHEK2 variants in hereditary cancer patients.

CHEK2 variants are associated with intermediate breast cancer risk, among other cancers. We aimed to comprehensively describe CHEK2 variants in a Spanish hereditary cancer (HC) cohort and adjust the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG-AMP) guidelines for their classification. First, three CHEK2 frequent variants were screened in a retrospective Hereditary Breast and Ovarian Cancer cohort of 516 patients. After, the whole CHEK2 coding region was analyzed by next-generation sequencing in 1848 prospective patients with HC suspicion. We refined ACMG-AMP criteria and applied different combined rules to classify CHEK2 variants and define risk alleles. We identified 10 CHEK2 null variants, 6 missense variants with discordant interpretation in ClinVar database, and 35 additional variants of unknown significance. Twelve variants were classified as (likely)-pathogenic; two can also be considered "established risk-alleles" and one as "likely risk-allele." The prevalence of (likely)-pathogenic variants in the HC cohort was 0.8% (1.3% in breast cancer patients and 1.0% in hereditary nonpolyposis colorectal cancer patients). Here, we provide ACMG adjustment guidelines to classify CHEK2 variants. We hope that this study would be useful for variant classification of other genes with low effect variants.

New Methylation Biomarker Panel for Early Diagnosis of Dysplasia or Cancer in High-Risk Inflammatory Bowel Disease Patients.

Background: The risk of developing colorectal cancer (CRC) is increased in patients with inflammatory bowel disease (IBD) of the colon. The aim of the study was to evaluate the effectiveness of selected methylation gene panel for the early detection of CRC in high-risk IBD patients. Methods: In a discovery phase, 73 biopsies of 48 IBD patients (associated or not to CRC) were analyzed from genome-wide DNA methylation analysis using the Illumina Human Methylation 450K BeadChip. The panel of 5 genes selected (EYA4, SLIT2, FLI1, USP44, and SND1) was validated prospectively using methylation-specific melting curve analysis in biopsies of diseased and adjacent healthy tissue of 203 patients: 38 with IBD and associated neoplasia, 81 patients with IBD (25 of them with high risk), 48 with sporadic CRC, and 36 healthy controls. Results: The prevalence of methylation was higher in patients with IBD and associated neoplasia (both in diseased and adjacent healthy tissue, 71% and 52%, respectively) than in healthy controls (2/36, 6%; P = 6.72E-05). Methylation in IBD patients at high risk of dysplasia or cancer was more frequently detected than in patients at low risk (92% vs 57%; odds ratio, 8.63; P = 0.001). EYA4 and SLIT2 were the markers most frequently methylated. Differences in methylation levels were more evident in healthy mucosa (82% vs 15% high vs low risk, respectively; P = 1.25E-05). Conclusions: Analysis of this panel of methylation markers may help in the early identification of colorectal dysplasia or cancer in high-risk IBD patients.

Optimization of RAS/BRAF Mutational Analysis Confirms Improvement in Patient Selection for Clinical Benefit to Anti-EGFR Treatment in Metastatic Colorectal Cancer.

In metastatic colorectal cancer (mCRC), recent studies have shown the importance to accurately quantify low-abundance mutations of the RAS pathway because anti-EGFR therapy may depend on certain mutation thresholds. We aimed to evaluate the added predictive value of an extended RAS panel testing using two commercial assays and a highly sensitive and quantitative digital PCR (dPCR). Tumor samples from 583 mCRC patients treated with anti-EGFR- (n = 255) or bevacizumab- (n = 328) based therapies from several clinical trials and retrospective series from the TTD/RTICC Spanish network were analyzed by cobas, therascreen, and dPCR. We evaluated concordance between techniques using the Cohen kappa index. Response rate, progression-free survival (PFS), and overall survival (OS) were correlated to the mutational status and the mutant allele fraction (MAF). Concordance between techniques was high when analyzing RAS and BRAF (Cohen kappa index around 0.75). We observed an inverse correlation between MAF and response in the anti-EGFR cohort (P < 0.001). Likelihood ratio analysis showed that a fraction of 1% or higher of any mutated alleles offered the best predictive value. PFS and OS were significantly longer in RAS/BRAF wild-type patients, independently of the technique. However, the predictability of both PFS and OS were higher when we considered a threshold of 1% in the RAS scenario (HR = 1.53; CI 95%, 1.12-2.09 for PFS, and HR = 1.9; CI 95%, 1.33-2.72 for OS). Although the rate of mutations observed among techniques is different, RAS and BRAF mutational analysis improved prediction of response to anti-EGFR therapy. Additionally, dPCR with a threshold of 1% outperformed the other platforms. Mol Cancer Ther; 16(9); 1999-2007. ©2017 AACR.

Mutational Heterogeneity in APC and KRAS Arises at the Crypt Level and Leads to Polyclonality in Early Colorectal Tumorigenesis.

Purpose: The majority of genomic alterations causing intratumoral heterogeneity (ITH) in colorectal cancer are thought to arise during early stages of carcinogenesis as a burst but only after truncal mutations in APC have expanded a single founder clone. We have investigated if the initial source of ITH is consequent to multiple independent lineages derived from different crypts harboring distinct truncal APC and driver KRAS mutations, thus challenging the prevailing monoclonal monocryptal model.Experimental Design: High-depth next-generation sequencing and SNP arrays were performed in whole-lesion extracts of 37 familial adenomatous polyposis colorectal adenomas. Also, ultrasensitive genotyping of hotspot mutations of APC and KRAS was performed using nanofluidic PCRs in matched bulk biopsies (n = 59) and crypts (n = 591) from 18 adenomas and seven carcinomas and adjacent normal tissues.Results: Multiple co-occurring truncal APC and driver KRAS alterations were uncovered in whole-lesion extracts from adenomas and subsequently confirmed to belong to multiple clones. Ultrasensitive genotyping of bulk biopsies and crypts revealed novel undetected APC mutations that were prominent among carcinomas, whereas abundant wild-type APC crypts were detected in adenomas. KRAS mutational heterogeneity within crypts was evident in both adenomas and carcinomas with a higher degree of concordance between biopsy and crypt genotyping in carcinomas. Nonrandom heterogeneity among crypts was also observed.Conclusions: The striking degree of nonrandom intercrypt heterogeneity in truncal and driver gene mutations observed in adenomas and carcinomas is consistent with a polycryptal model derived from multiple independent initiation linages as the source of early ITH in colorectal carcinogenesis. Clin Cancer Res; 23(19); 5936-47. ©2017 AACR.

Nanofluidic Digital PCR and Extended Genotyping of RAS and BRAF for Improved Selection of Metastatic Colorectal Cancer Patients for Anti-EGFR Therapies.

The clinical significance of low-frequent RAS pathway-mutated alleles and the optimal sensitivity cutoff value in the prediction of response to anti-EGFR therapy in metastatic colorectal cancer (mCRC) patients remains controversial. We aimed to evaluate the added value of genotyping an extended RAS panel using a robust nanofluidic digital PCR (dPCR) approach. A panel of 34 hotspots, including RAS (KRAS and NRAS exons 2/3/4) and BRAF (V600E), was analyzed in tumor FFPE samples from 102 mCRC patients treated with anti-EGFR therapy. dPCR was compared with conventional quantitative PCR (qPCR). Response rates, progression-free survival (PFS), and overall survival (OS) were correlated to the mutational status and the mutated allele fraction. Tumor response evaluations were not available in 9 patients and were excluded for response rate analysis. Twenty-two percent of patients were positive for one mutation with qPCR (mutated alleles ranged from 2.1% to 66.6%). Analysis by dPCR increased the number of positive patients to 47%. Mutated alleles for patients only detected by dPCR ranged from 0.04% to 10.8%. An inverse correlation between the fraction of mutated alleles and radiologic response was observed. ROC analysis showed that a fraction of 1% or higher of any mutated alleles offered the best predictive value for all combinations of RAS and BRAF analysis. In addition, this threshold also optimized prediction both PFS and OS. We conclude that mutation testing using an extended gene panel, including RAS and BRAF with a threshold of 1% improved prediction of response to anti-EGFR therapy. Mol Cancer Ther; 15(5); 1106-12. ©2016 AACR.

Quantification of unmethylated Alu (QUAlu): a tool to assess global hypomethylation in routine clinical samples.

Hypomethylation of DNA is a hallmark of cancer and its analysis as tumor biomarker has been proposed, but its determination in clinical settings is hampered by lack of standardized methodologies. Here, we present QUAlu (Quantification of Unmethylated Alu), a new technique to estimate the Percentage of UnMethylated Alu (PUMA) as a surrogate for global hypomethylation. QUAlu consists in the measurement by qPCR of Alu repeats after digestion of genomic DNA with isoschizomers with differential sensitivity to DNA methylation. QUAlu performance has been evaluated for reproducibility, trueness and specificity, and validated by deep sequencing. As a proof of use, QUAlu has been applied to a broad variety of pathological examination specimens covering five cancer types. Major findings of the preliminary application of QUAlu to clinical samples include: (1) all normal tissues displayed similar PUMA; (2) tumors showed variable PUMA with the highest levels in lung and colon and the lowest in thyroid cancer; (3) stools from colon cancer patients presented higher PUMA than those from control individuals; (4) lung squamous cell carcinomas showed higher PUMA than lung adenocarcinomas, and an increasing hypomethylation trend associated with smoking habits. In conclusion, QUAlu is a simple and robust method to determine Alu hypomethylation in human biospecimens and may be easily implemented in research and clinical settings.

Relationship between methylation and colonic inflammation in inflammatory bowel disease.

AIM: To investigate the relationship between the methylation status in the SLIT2 and TGFB2 promoters and colonic inflammation in inflammatory bowel disease patients. METHODS: We evaluated the methylation status of 2 genes (SLIT2 and TGFB2) in 226 biopsies taken from 62 colonoscopies of 38 patients (29 ulcerative colitis and 9 Crohn's colitis) using methylation-specific melting curve analysis. The relationships between methylation status and clinical, biological, endoscopic and histological activities were evaluated. Twenty-three of the 38 patients had a second colonoscopy and were included in a longitudinal analysis. Numerical results were given as the means ± SD of the sample and range, except when specified. Student t analysis, U Mann Whitney and ANOVA factor were used to compare the means. Qualitative results were based on the χ(2) test. RESULTS: SLIT2 methylation was more frequent in samples with endoscopic activity than with endoscopic remission (55% vs 18%, P < 0.001). SLIT2 methylation was also higher in samples with acute inflammation (56.5%) than in samples with chronic (24%) or absent inflammation (15%) (P < 0.001). For TGFB2 methylation, the correlation was only significant with endoscopic activity. Methylation was higher in the distal colon for both genes (P < 0.001 for SLIT2 and P = 0.022 for TGFB2). In the multivariate analysis, only inflammation status (and not disease duration or extension) was independently associated with SLIT2 methylation [OR = 6.6 (95%CI: 1.65-27.36), P = 0.009]. In the longitudinal analysis, the maintenance of endoscopic remission was protective for methylation. CONCLUSION: Endoscopic and histological inflammation are predictive for SLIT2 methylation.

DNA methylation biomarkers for noninvasive diagnosis of colorectal cancer.

DNA methylation biomarkers for noninvasive diagnosis of colorectal cancer (CRC) and precursor lesions have been extensively studied. Different panels have been reported attempting to improve current protocols in clinical practice, although no definite biomarkers have been established. In the present study, we have examined patient biopsies starting from a comprehensive analysis of DNA methylation differences between paired normal and tumor samples in known cancer-related genes aiming to select the best performing candidates informative for CRC diagnosis in stool samples. Five selected markers were considered for subsequent analyses in independent biologic cohorts and in silico data sets. Among the five selected genes, three of them (AGTR1, WNT2 and SLIT2) were validated in stool DNA of affected patients with a detection sensitivity of 78% [95% confidence interval (CI), 56%-89%]. As a reference, DNA methylation of VIM and SEPT9 was evaluated in a subset of stool samples yielding sensitivities of 55% and 20%, respectively. Moreover, our panel may complement histologic and endoscopic diagnosis of inflammatory bowel disease (IBD)-associated neoplasia, as it was also efficient detecting aberrant DNA methylation in non-neoplastic tissue samples from affected patients. This novel panel of specific methylation markers can be useful for early diagnosis of CRC using stool DNA and may help in the follow-up of high-risk patients with IBD.

Deep hypothermia protects against acute hypoxia in vivo in rats: a mechanism related to the attenuation of oxidative stress.

There is growing interest in using hypothermia to prevent hypoxic damage in clinical and experimental models, although the mechanisms regulated by hypothermia are still unclear. As reactive oxygen and nitrogen species are the main factors causing cellular damage, our objective was to study the scope of hypothermia in preventing hypoxia-induced oxidative damage. We analysed systemic and hepatic indicators of oxidative stress after an acute hypoxic insult (10% oxygen in breathing air) in normothermic (37°C body temperature) and hypothermic conditions (22°C) in rats. Exposure to hypoxia resulted in tissue damage (aspartate aminotransferase increased from 54.6 ± 6.9 U l(-1) in control animals to 116 ± 1.9 U l(-1) in hypoxia, and alanine aminotransferase increased from 19 ± 0.8 to 34 ± 2.9 U l(-1)), oxidative stress (nitric oxide metabolites increased from 10.8 ± 0.4 µM in control rats to 23 ± 2.7 µM in hypoxia, and thiobarbituric reactive substances increased from 3.3 ± 0.2 to 5.9 ± 0.4 nm) and antioxidant consumption (reduced/oxidized glutathione ratio changed from 9.8 ± 0.3 to 6.8 ± 0.3). In contrast, when hypothermia was applied prior to hypoxia, the situation was reversed, with a reduction in aspartate aminotransferase (from 116 ± 1.9 in hypoxic animals to 63 ± 7.8 U l(-1) in animals exposed to hypothermia followed by hypoxia), alanine aminotransferase (from 34 ± 2.9 to 19 ± 0.9 U l(-1)), oxidative stress (nitric oxide metabolites decreased from 23 ± 2.7 to 17.8 ± 1.9 µM and thiobarbituric acid-reactive substances decreased from 5.9 ± 0.4 to 4.3 ± 0.2 nm) and antioxidant preservation (reduced/oxidized glutathione ratio changed from 6.8 ± 0.3 to 11.1 ± 0.1). Hypoxia induced a decrease in liver enzymatic antioxidant activities even during hypothermia. Both treatments, hypoxia and hypothermia, produced a similar increase in hepatic caspase-3 activity. In conclusion, hypothermia prevented the tissue damage and oxidative stress elicited by hypoxia. Our results provide new evidence concerning the protective mechanism of hypothermia in vivo.

Novel methylation panel for the early detection of neoplasia in high-risk ulcerative colitis and Crohn's colitis patients.

BACKGROUND: Patients with ulcerative colitis and Crohn's colonic disease are at increased risk of developing colorectal cancer (CRC). The aim of the study was to analyze the methylation status of selected genes as a risk marker for CRC in inflammatory bowel disease (IBD) patients. METHODS: We evaluated the methylation status of four genes (TGFB2, SLIT2, HS3ST2, and TMEFF2) in biopsies of four groups of patients: 60 patients with sporadic CRC, 32 patients with IBD-associated neoplasia, 85 patients with IBD without associated neoplasia (20 at high risk and 65 at low risk), and 28 healthy controls. Methylation-specific melting curve analysis (MS-MCA) was used. Methylation status of these genes was also assessed in stool DNA from 60 IBD patients without neoplasia. RESULTS: Methylation of the panel of genes analyzed was a very common phenomenon (78%) in IBD-associated neoplasia. The prevalence of methylation in adjacent nonneoplastic mucosa was also high (12/30). This prevalence was higher than in mucosa from healthy controls (2/28;7.1%; P < 0.05). Methylation of SLIT2 and TMEFF2 was more frequently detected in the mucosa of IBD patients at high risk of dysplasia or cancer (15/20) than patients at low risk (32/63) (P = 0.05 and P = 0.03, respectively). When stool samples were assessed, only SLIT2 gene methylation was more frequently methylated in the group of patients at high risk of dysplasia or cancer (4/16) compared to low risk (0/37) (P = 0.006). CONCLUSIONS: Analysis of a panel of methylation markers may help in the early identification of colorectal dysplasia or cancer in high-risk IBD patients.

Nanofluidic digital PCR for KRAS mutation detection and quantification in gastrointestinal cancer.

BACKGROUND: Concomitant quantification of multiple mutant KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) alleles may provide information in addition to that provided by standard mutation-detection procedures. We assessed the feasibility of a nanofluidic digital PCR array platform to detect and quantify KRAS mutations simultaneously in clinically relevant samples. METHODS: We assessed 2 groups of patients (colorectal and pancreatic disease): Group 1 consisted of 27 patients with colorectal carcinomas, 14 patients with adenomas, and 5 control individuals; group 2 consisted of 42 patients with pancreatic carcinoma, 4 with adenocarcinomas of the ampulla, and 6 with chronic pancreatitis). Digital PCR was performed with the Digital Array Chip (Fluidigm). RESULTS: Nanofluidic digital PCR detected mutant alleles at 0.05% to 0.1%, depending on the variant analyzed. For the colorectal disease group, conventional PCR detected 9 (64%) of 14 adenomas that were positive for KRAS mutants, whereas digital PCR increased this number to 11 (79%) of 14. Sixteen (59%) of 27 carcinomas showed KRAS mutation with conventional PCR. Two additional cases were detected with digital PCR. In 5 cases (3 adenomas, 2 carcinomas), the total number of mutant alleles changed. For the pancreatic disease group, digital PCR increased the number of positive cases from 26 to 34 (81%) and identified ≥ 2 mutant alleles in 25 cases, compared with conventional PCR, which identified multiple KRAS mutant alleles in only 12 cases. A good correlation was observed between results obtained with tumor biopsies and those obtained with pancreatic juice. CONCLUSIONS: Digital PCR provides a robust, quantitative measure of the proportion of KRAS mutant alleles in routinely obtained samples. It also allows a better classification of tumors, with potential clinical relevance.

Novel methylation panel for the early detection of colorectal tumors in stool DNA.

BACKGROUND: Previous studies showed that the assessment of promoter hypermethylation of a limited number of genes in tumor biopsies may identify the majority of colorectal tumors. This study aimed to assess the clinical usefulness of a panel of methylation biomarkers in stool DNA in the identification of colorectal tumors, using methylation-specific melting curve analysis (MS-MCA), a technique that simultaneously analyzes all cytosine-phosphate-guanine (CpG) residues within a promoter. MATERIALS AND METHODS: The promoter methylation status of 4 tumor-related genes (RARB2, p16INK4a, MGMT, and APC) was analyzed in DNA stool samples and corresponding tissues in an initial set of 12 patients with newly diagnosed primary colorectal carcinomas and 20 patients with newly diagnosed colorectal adenomas, using methylation-specific polymerase chain reaction. Results were replicated in a set of 82 patients (20 healthy subjects, 16 patients with inflammatory bowel disease (IBD), 20 patients with adenomas, and 26 patients with carcinomas), using MS-MCA analyses. RESULTS: In the initial set, >or= 1 positive methylation marker was detected in the stools of 9 of 12 patients (75%) with carcinomas and 12 of 20 patients (60%) with adenomas, with no false-positive results. Stool analyses missed 7 methylated lesions (25%). In the replication set, stool DNA testing detected 16 of 26 carcinomas (62%) and 8 of 20 adenomas (40%). The MS-MCAs missed 14 methylated tumors (37%). No aberrant methylation was evident in healthy subjects, but the RARB2 marker was positive in 2 of 15 stool samples (13%) of patients with IBD. CONCLUSION: Analysis via MS-MCA of a panel of methylation markers in stool DNA may offer a good alternative in the early, noninvasive detection of colorectal tumors.

Caspase-3 activity, response to chemotherapy and clinical outcome in patients with colon cancer.

BACKGROUND AND AIMS: The prognostic value of the degree of apoptosis in colorectal cancer is controversial. This study evaluates the putative clinical usefulness of measuring caspase-3 activity as a prognostic factor in colonic cancer patients receiving 5-fluoracil adjuvant chemotherapy. MATERIALS AND METHODS: We evaluated caspase-3-like protease activity in tumours and in normal colon tissue. Specimens were studied from 54 patients. These patients had either stage III cancer (Dukes stage C) or high-risk stage II cancer (Dukes stage B2 with invasion of adjacent organs, lymphatic or vascular infiltration or carcinoembryonic antigen [CEA] >5). Median follow-up was 73 months. Univariate analysis was performed previously to explore the relation of different variables (age, sex, preoperative CEA, tumour size, Dukes stage, vascular invasion, lymphatic invasion, caspase-3 activity in tumour and caspase-3 activity in normal mucosa) as prognostic factors of tumour recurrence after chemotherapy treatment. Subsequently, a multivariate Cox regression model was performed. RESULTS: Median values of caspase-3 activity in tumours were more than twice those in normal mucosa (88.1 vs 40.6 U, p=0.001), showing a statistically significant correlation (r=0.34). Significant prognostic factors of recurrence in multivariate analysis were: male sex (odds ratio, OR=3.53 [1.13-10.90], p=0.02), age (OR=1.09 [1.01-1.18], p=0.03), Dukes stage (OR=1.93 [1.01-3.70]), caspase-3 activity in normal mucosa (OR=1.02 [1.01-1.04], p=0.017) and caspase-3 activity in tumour (OR=1.02 [1.01-1.03], p=0.013). CONCLUSION: Low caspase-3 activity in the normal mucosa and tumour are independent prognostic factors of tumour recurrence in patients receiving adjuvant 5-fluoracil-based treatment in colon cancer, correlating with poor disease-free survival and higher recurrence rate.

Apoptosis inhibition during preservation by fructose-1,6-diphosphate and theophylline in rat intestinal transplantation.

OBJECTIVE: This study evaluated the effect of fructose-1,6-diphosphate (FDP), theophylline, or the addition of both together to the preservation solution (University of Wisconsin [UW]) on apoptosis during preservation and the effect of apoptosis minimization on the early reperfusion period after transplantation. DESIGN: Prospective, randomized, and controlled animal study. SETTING: Laboratory of a research institute. SUBJECT: Male Wistar rats. INTERVENTIONS: The jejunum was isolated and preserved for 6 hrs in UW solution. FDP and theophylline were added to the UW solution to evaluate their effects on apoptosis both alone and together. The role of adenosine with respect to FDP was examined by increasing endogenous adenosine. In addition, rats were subjected to intestinal transplantation for the evaluation of the effect of apoptosis on bacterial translocation, histology, and neutrophil infiltration after reperfusion. MEASUREMENTS AND MAIN RESULTS: Caspase-3 activity, assayed both in vitro or by cleaved caspase-3 levels in Western blots or immunohistochemically, and the number of terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick-end labeling (TUNEL)-positive cells decreased with FDP and with theophylline addition to UW solution. Increase of endogenous adenosine reversed the antiapoptotic effect of FDP. FDP and theophylline together demonstrated a more pronounced antiapoptotic effect and prevented bacterial translocation after transplantation. CONCLUSION: Supplementary FDP to UW solution decreased apoptosis through an adenosine-independent mechanism. Addition of theophylline to UW solution decreased both apoptosis and bacterial translocation. Concomitant theophylline and FDP addition to preservation solution is recommended to maintain low levels of apoptosis during intestinal hypothermic preservation and to decrease bacterial translocation.

Apoptosis inhibition plays a greater role than necrosis inhibition in decreasing bacterial translocation in experimental intestinal transplantation.

BACKGROUND: During small-bowel transplantation, necrosis and apoptosis are involved in the destruction of intestinal epithelial cells. This study was conducted to assess which mode of cell death plays a greater role as a trigger of the bacterial translocation (BT) associated with intestinal transplantation. METHODS: The following experimental groups were studied: sham, Tx (intestinal transplantation), Tx + poly (ADP-ribose) synthetase (PARS) inhibitor 3-aminobenzamide (3-AB), and Tx + caspase inhibitor Z-VAD-fmk. Histological analysis, caspase-3 activity, DNA fragmentation, and BT were measured in tissue samples after transplantation. RESULTS: During intestinal transplantation, apoptosis and necrosis both increased, showing graft injury and high levels of BT. Rats treated with 3-AB showed histological protection of the transplanted graft and a tendency toward lower BT despite the existence of high apoptosis levels. The rats treated with Z-VAD showed histological protection of the transplanted graft and decreased levels of caspase-3 and DNA fragmentation. The Tx + Z-VAD group showed the lowest levels of BT in all tissues. CONCLUSIONS: In small intestinal transplantation, both apoptosis and cell necrosis give rise to histological injury and BT. Apoptosis inhibition and necrosis inhibition treatments protect intestinal grafts from ischemia/reperfusion injury; Z-VAD supplementation has a greater effect on BT prevention than does administration of the PARS inhibitor 3-AB.

Administration of nitric oxide with caspase inhibitors minimizes bacterial translocation in experimental intestinal transplantation.

BACKGROUND: Bacterial translocation (BT) has been suggested to be responsible for the high incidence of infections occurring after small-bowel transplantation (Trp). Nitric oxide (NO) and apoptosis could affect cell demise. The aim of this study was to asses whether supplementation of University of Wisconsin (UW) solution with NO donors and apoptosis inhibitors can abolish BT in Trp. METHODS: The following experimental groups were studied: sham, Trp, intestinal transplantation, Trp+spermine NONOate (NONOs), and Trp+NONOs+caspase inhibitor Z-Val-Ala-Asp(Ome)-fluoromethylketone(Z-VAD-fmk). Histologic analysis, caspase-3 activity, DNA fragmentation, and BT from graft to mesenteric lymph nodes, liver, and spleen were measured in tissue samples after transplantation. RESULTS: During intestinal transplantation, apoptosis and necrosis were increased, showing graft injury and high levels of BT. The rats treated with NONOs showed a histologic protection of transplanted graft and a decrease in BT despite caspase-3 and DNA fragmentation-inducing effects. Administration of caspase inhibitor Z-VAD to NONOs-treated rats reversed the NO apoptosis-inducing effects and showed the lowest levels of BT in all tissues. CONCLUSIONS: Exogenous administration of NO associated with the inhibition of apoptosis maintains the graft in optimal conditions in terms of BT and improves the histology of the graft after intestinal transplantation in rats.