Circ_0002711 knockdown suppresses cell growth and aerobic glycolysis by modulating miR-1244/ROCK1 axis in ovarian cancer

It has been well investigated that circular RNAs (circRNAs) play important roles in various cancers. The function of circ_0002711 and its underlying mechanisms in ovarian cancer (OC) remain unknown. qRT-PCR and western blot were performed to detect the expressions of circ_0002711, microRNA-1244 (miR-1244), and Rho kinase 1 (ROCK1) in OC tissues and cells. MTT assay and colony formation assay were employed to evaluate cell proliferation. Detection of lactate production, glucose uptake, and ATP level and oxygen consumption were used to determine Warburg effect. Western blot was used to examine glycolysis or proliferationrelated genes. Dual-luciferase reporter assay and RIP pull down assay were used to address the relationship among circ_0002711, miR-1244, and ROCK1. In vivo tumor growth was evaluated in nude mice. Circ_0002711 was upregulated in OC tissues and cell lines. Circ_0002711 downregulation inhibited cell viability, colony formation ability and aerobic glycolysis. Circ_0002711 contained binding sites with miR1244. Moreover, loss of miR-1244 undermined circ_0002711 downregulation-mediated function. ROCK1 contained binding sites with miR-1244. MiR-1244 upregulation suppressed cell proliferation and aerobic glycolysis, which was rescued by enhanced expression of ROCK1. Circ_0002711 knockdown hampered ROCK1 expression by upregulating miR-1244 expression. Finally, decreased expression of circ_0002711 inhibited tumor growth in vivo. Circ_0002711/miR-1244/ROCK1 axis regulated Warburg effect and tumor growth in vivo.

Real-world cure rates for hepatitis C virus treatments that include simeprevir and/or sofosbuvir are comparable to clinical trial results

AIM

To assess the real-world effectiveness and cost of simeprevir (SMV), and/or sofosbuvir (SOF)-based therapy for chronic hepatitis C virus (HCV) infection.

METHODS

The real-world performance of patients treated with SMV/SOF ± ribavirin (RBV), SOF/RBV, and SOF/RBV with pegylated-interferon (PEG) were analyzed in a consecutive series of 508 patients with chronic HCV infection treated at a single academic medical center. Patients with genotypes 1 through 4 were included. Rates of sustained virological response - the absence of a detectable serum HCV RNA 12 wk after the end of treatment [sustained virological response (SVR) 12] - were calculated on an intention-to-treat basis. Costs were calculated from the payer’s perspective using Medicare/Medicaid fees and Redbook Wholesale Acquisition Costs. Patient-related factors associated with SVR12 were identified using multivariable logistic regression.

RESULTS

SVR12 rates were as follows: 86% (95%CI: 80%-91%) among 178 patients on SMV/SOF ± RBV; 62% (95%CI: 55%-68%) among 234 patients on SOF/RBV; and 78% (95%CI: 68%-86%) among 96 patients on SOF/PEG/RBV. Mean costs-per-SVR12 were $174442 (standard deviation: ± $18588) for SMV/SOF ± RBV; $223003 (± $77946) for SOF/RBV; and $126496 (± $31052) for SOF/PEG/RBV. Among patients on SMV/SOF ± RBV, SVR12 was less likely in patients previously treated with a protease inhibitor [odds ratio (OR): 0.20, 95%CI: 0.06-0.56]. Higher bilirubin (OR: 0.47, 95%CI: 0.30-0.69) reduced the likelihood of SVR12 among patients on SOF/RBV, while FIB-4 score ≥ 3.25 reduced the likelihood of SVR12 (OR: 0.18, 95%CI: 0.05-0.59) among those on SOF/PEG/RBV.

CONCLUSION

SVR12 rates for SMV and/or SOF-based regimens in a diverse real-world population are comparable to those in clinical trials. Treatment failure accounts for 27% of costs.

Clinical, Biochemical, and Genetic Characterization of North American Patients With Erythropoietic Protoporphyria and X-linked Protoporphyria

Importance

Autosomal recessive erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare photodermatoses presenting with variable degrees of painful phototoxicity that markedly affects quality of life. The clinical variability, determinants of severity, and genotype/phenotype correlations of these diseases are not well characterized.

Objective

To describe the baseline clinical characteristics, genotypes, and determinants of disease severity in a large patient cohort with EPP or XLP.

Design, Setting, and Participants

A prospective observational study was conducted among patients with confirmed diagnoses of EPP or XLP from November 1, 2010, to December 6, 2015, at 6 academic medical centers of the Porphyrias Consortium of the National Institutes of Health Rare Diseases Clinical Research Network. Detailed medical histories, including history of phototoxicity and treatment, were collected on standardized case report forms. Patients underwent baseline laboratory testing, total erythrocyte protoporphyrin (ePPIX) testing, and molecular genetic testing. Data were entered into a centralized database.

Main Outcomes and Measures

Results of biochemical and genetic tests were explored for association with clinical phenotype in patients with EPP or XLP.

Results

Of the 226 patients in the study (113 female and 113 male patients; mean [SD] age, 36.7 [17.0] years), 186 (82.3%) had EPP with a FECH (OMIM 612386) mutation and the common low-expression FECH allele IVS3-48T>C, and only 1 patient had 2 FECH mutations. Twenty-two patients had XLP (9.7%; 10 male and 12 female patients), and 9 patients (4.0%) had elevated ePPIX levels and symptoms consistent with protoporphyria but no detectable mutation in the FECH or ALAS2 (OMIM 301300) gene. Samples of DNA could not be obtained from 8 patients. Patients' mean (SD) age at symptom onset was 4.4 (4.4) years. Anemia (107 [47.3%]), history of liver dysfunction (62 [27.4%]), and gallstones (53 [23.5%]) were commonly reported. Higher ePPIX levels were associated with earlier age of symptom onset (median ePPIX levels for those who developed symptoms before vs after 1 year of age, 1744 vs 1567 µg/dL; P = .02), less sun tolerance (median ePPIX levels for those reporting symptoms before vs after 10 minutes of sun exposure, 2233 vs 1524 µg/dL; P ≤ .001), and increased risk of liver dysfunction (median ePPIX levels for those with liver dysfunction vs normal liver function, 2016 vs 1510 µg/dL; P = .003). Patients with EPP and FECH missense mutations had significantly lower ePPIX levels than those with other mutations (1462 vs 1702 µg/dL; P = .01). Male patients with XLP had significantly higher ePPIX levels, on average, than did patients with EPP (3574 vs 1669 µg/dL; P < .001). Marked clinical variability was seen in female patients with XLP owing to random X-chromosomal inactivation.

Conclusions and Relevance

These data suggest that higher ePPIX levels are a major determinant of disease severity and risk of liver dysfunction in patients with EPP or XLP. These findings provide a framework for clinical monitoring and management of these disorders.

Factors associated with success of telaprevir- and boceprevir-based triple therapy for hepatitis C virus infection

AIM

To evaluate new therapies for hepatitis C virus (HCV), data about real-world outcomes are needed.

METHODS

Outcomes of 223 patients with genotype 1 HCV who started telaprevir- or boceprevir-based triple therapy (May 2011-March 2012) at the Mount Sinai Medical Center were analyzed. Human immunodeficiency virus-positive patients and patients who received a liver transplant were excluded. Factors associated with sustained virological response (SVR24) and relapse were analyzed by univariable and multivariable logistic regression as well as classification and regression trees. Fast virological response (FVR) was defined as undetectable HCV RNA at week-4 (telaprevir) or week-8 (boceprevir).

RESULTS

The median age was 57 years, 18% were black, 44% had advanced fibrosis/cirrhosis (FIB-4 ≥ 3.25). Only 42% (94/223) of patients achieved SVR24 on an intention-to-treat basis. In a model that included platelets, SVR24 was associated with white race [odds ratio (OR) = 5.92, 95% confidence interval (CI): 2.34-14.96], HCV sub-genotype 1b (OR = 2.81, 95%CI: 1.45-5.44), platelet count (OR = 1.10, per x 10⁴ cells/μL, 95%CI: 1.05-1.16), and IL28B CC genotype (OR = 3.54, 95%CI: 1.19-10.53). Platelet counts > 135 x 10³/μL were the strongest predictor of SVR by classification and regression tree. Relapse occurred in 25% (27/104) of patients with an end-of-treatment response and was associated with non-FVR (OR = 4.77, 95%CI: 1.68-13.56), HCV sub-genotype 1a (OR = 5.20; 95%CI: 1.40-18.97), and FIB-4 ≥ 3.25 (OR = 2.77; 95%CI: 1.07-7.22).

CONCLUSION

The SVR rate was 42% with telaprevir- or boceprevir-based triple therapy in real-world practice. Low platelets and advanced fibrosis were associated with treatment failure and relapse.

Liver Transplantation for Acute Intermittent Porphyria: Biochemical and Pathologic Studies of the Explanted Liver

Acute intermittent porphyria (AIP) is an autosomal-dominant hepatic disorder caused by the half-normal activity of hydroxymethylbilane (HMB) synthase. Symptomatic individuals experience life-threatening acute neurovisceral attacks that are precipitated by factors that induce the hepatic expression of 5-aminolevulinic acid synthase 1 (ALAS1), resulting in the marked accumulation of the putative neurotoxic porphyrin precursors 5-aminolevulinic acid (ALA) and porphobilinogen (PBG). Here, we provide the first detailed description of the biochemical and pathologic alterations in the explanted liver of an AIP patient who underwent orthotopic liver transplantation (OLT) due to untreatable and debilitating chronic attacks. After OLT, the recipient's plasma and urinary ALA and PBG rapidly normalized, and her attacks immediately stopped. In the explanted liver, (a) ALAS1 mRNA and activity were elevated approximately ~3- and 5-fold, and ALA and PBG concentrations were increased ~3- and 1,760-fold, respectively; (b) uroporphyrin III concentration was elevated; (c) microsomal heme content was sufficient, and representative cytochrome P450 activities were essentially normal; (d) HMB synthase activity was approximately half-normal (~42%); (e) iron concentration was slightly elevated; and (f) heme oxygenase I mRNA was increased approximately three-fold. Notable pathologic findings included nodular regenerative hyperplasia, previously not reported in AIP livers, and minimal iron deposition, despite the large number of hemin infusions received before OLT. These findings suggest that the neurovisceral symptoms of AIP are not associated with generalized hepatic heme deficiency and support the neurotoxicity of ALA and/or PBG. Additionally, they indicate that substrate inhibition of hepatic HMB synthase activity by PBG is not a pathogenic mechanism in acute attacks.

Expression of Smad4, TGF-βRII, and p21waf1 in esophageal squamous cell carcinoma tissue

Esophageal squamous cell carcinoma (SCC) possesses one of the worst prognoses out of the digestive carcinomas. Several studies have suggested that transforming growth factor β receptor type II (TGF-βRII), Smad family member 4 (Smad4) and p21 wild-type p53-activated factor 1 (p21^waf1) are associated with esophageal SCC. The aim of the present study was to evaluate the effect of Smad4, TGF-βRII and p21^waf1 in esophageal squamous cancer tissue and the pathological significance of the effect. An immunohistochemical method was used to evaluate the expression levels of Smad4, TGF-βRII and p21^waf1 in specimens of esophageal SCC lesions obtained from 80 patients. It was found that the expression of Smad4, TGF-βRII and p21^waf1 in histologically-classified grade I esophageal SCC, without invasion or lymph node metastasis, was markedly higher compared with grade III esophageal SCC that had invaded into the deep muscular or serous layer and metastasized to the lymph nodes (P<0.05). Analysis of the expression level of Smad4, TGF-βRII and p21^waf1, as well as the clinical and pathological characteristics of esophageal SCC, revealed that the three proteins may be associated with the carcinogenesis, biological behavior and prognosis of esophageal SCC, parallel to the pathological stage and cell grade.

Diabetes mellitus and advanced liver fibrosis are risk factors for severe anaemia during telaprevir-based triple therapy

BACKGROUND & AIMS

Adding telaprevir to pegylated-interferon and ribavirin increased both response rates and side effects of hepatitis C virus (HCV) treatment. We identified variables associated with severe anaemia during telaprevir-based triple therapy.

METHODS

An observational study was performed on 142 HCV-infected patients between June 2011 and March 2012. All subjects completed 12 weeks of telaprevir-based triple therapy or discontinued early because of anaemia. Severe anaemia was defined by a haemoglobin≤8.9 g/dl; advanced fibrosis was determined by Fib-4≥3.25.

RESULTS

The 47 (33%) patients who developed severe anaemia were similar to those who did not in sex, race, and prior response to dual therapy, but they were more likely to have diabetes (23.4% vs. 6.3%, P<0.01), advanced fibrosis (46.8% vs. 29.5%, P=0.04) and a history of anaemia during previous dual therapy (29.7% vs. 11.4%, P=0.02). Patients developing severe anaemia were older (59 vs. 56 years, P=0.02), had lower baseline platelet counts (134 vs. 163×10(9) /L, P=0.04), haemoglobin (14.0 vs. 15.0 g/dl, P<0.01), estimated glomerular filtration rate (79 vs. 90 ml/min/1.73 m2, P=0.03) and a higher median ribavirin/weight ratio (14.9 vs. 13.2 mg/kg, P<0.01). In multivariable logistic regression, presence of diabetes (OR=5.61, 95% CI: 1.59-19.72), Fib-4≥3.25 (OR=3.09, 95% CI: 1.28-7.46), higher ribavirin/weight ratio (OR=1.31 per mg/kg, 95% CI: 1.13-1.52) and lower baseline haemoglobin (OR=0.57 per g/dl, 95% CI, 0.41-0.80) were independently associated with developing severe anaemia.

CONCLUSIONS

Severe anaemia occurred in one-third of patients receiving telaprevir-based triple therapy. Risk was greater in patients with diabetes, advanced liver fibrosis, higher ribavirin/weight ratio and lower baseline haemoglobin.

A patient with persistent pruritus

We present a patient with an initial and acute presentation of jaundice and marked persistent pruritus. Laboratory and radiology test results eliminated the possibility of acute hepatitis A/B/C viral infections, primary biliary cirrhosis, autoimmune hepatitis, Wilson disease, paraneoplastic cholestasis, and obstructive biliary disease. Centrilobular cholestasis was prominent in a liver biopsy specimen. Benign recurrent intrahepatic cholestasis (BRIC) was diagnosed through a review of the clinical history, available data, and the subsequent exclusion of other possible etiologies. The patient's clinical features resolved within 3 months of medical treatment.

Patient with hepatitis B and alcoholic liver disease before and after liver transplantation

We present the case of a patient with hepatitis B virus infection and alcohol use (30 g/day by self-report) who developed cirrhosis and proceeded to liver transplantation at age 49. The explanted liver showed cirrhosis with evidence of burnt-out steatohepatitis and hepatitis B virus and a 0.7-cm focus of well-differentiated hepatocellular carcinoma. He was managed following transplant with tacrolimus, prednisone, lamivudine, adefovir, and hepatitis B immune globulin infusions. His post-transplant course was complicated by several episodes of elevated liver enzymes. Liver biopsy 3 months after liver transplantation showed acute rejection and mild steatohepatitis. Liver biopsy 6 months after liver transplantation showed marked steatosis (approximately 95%) with moderate steatohepatitis and evidence of treated rejection. Subsequent biopsies (15 and 21 months post liver transplantation) showed resolution of the steatohepatitis, but development of chronic rejection. We discuss the interaction of alcoholic liver disease and hepatitis B virus in the development of cirrhosis and hepatocellular carcinoma, as well as the role of liver transplantation in these patients.

Effect of ischemia-reperfusion on the incidence of acute cellular rejection and timing of histologic hepatitis C virus recurrence after liver transplantation

BACKGROUND

Because of a critical shortage of deceased donor (DD) livers, more extended criteria allografts are being utilized; these allografts are at increased risk for ischemia-reperfusion injury (IRI). We assessed whether, in a large cohort of patients transplanted for hepatitis C virus (HCV) either via a DD or live donor (LD), there was a relationship between the degree of IRI and the frequency and timing of acute cellular rejection (ACR) and histologic HCV recurrence.

METHODS

During an 8-year study, patients were separated into four groups based on peak alanine aminotransferase (ALT) levels and three groups based on severity of IRI on postreperfusion liver biopsy.

RESULTS

The mean follow-up time of 433 DD and 44 LD recipients was 1212 days. We noted a strong correlation in DD between peak ALT and the histologic degree of IRI (P = .01). There was no difference in the incidence or grade of ACR among the four groups. There was no correlation between the severity of IRI and the incidence or time to histologic recurrence of HCV.

CONCLUSIONS

The magnitude of peak ALT correlated with the severity of IRI on postreperfusion liver biopsy. Among this large HCV cohort, there was no correlation between the severity of IRI and the incidence or timing of histologic HCV recurrence or incidence of ACR.

Long-term care of the liver transplant recipient

As survival increases after liver transplantation, common issues that arise involve immunosuppression-related complications and primary health care. Proper emphasis on the prevention and treatment of post-liver transplant complications, such as diabetes mellitus, dyslipidemia, renal dysfunction, osteoporosis, and obesity, requires careful screening and long-term surveillance to minimize the progression of these complications. Active involvement by internists and subspecialists is necessary and a multidisciplinary approach should be undertaken. Liver transplantation should be viewed as a lifelong commitment by both patient and physician.

Hepatitis C immune globulin (human) for the prevention of viral recurrence after liver transplantation

Immunoglobulin therapy has been used extensively in the treatment of infectious diseases. Hepatitis B immunoglobulin (HBIg) reduces the onset of infection in post-percutaneous exposure to Hepatitis B virus (HBV) and in infants of hepatitis B surface antigen (HBsAg)-positive mothers; it also significantly reduces the risk of recurrent HBV infection in liver transplant recipients, thus increasing the survival rate of this population. Prior to 1990, when plasma donors were not screened for the hepatitis C virus (HCV) antibody, the prevalence of HCV viremia after a liver transplant was found to be lower in those patients receiving HBIg containing anti-HCV antibodies. Phase I trials with chimpanzees demonstrated the ability of hepatitis C immune globulin (human) to decrease hepatic inflammation and to neutralize the HCV antibody, but this effect was not sustained over time. Phase I/II human studies have currently been unable to replicate the animal studies, but further trials are planned.

Marked Differences in acute cellular rejection rates between living-donor and deceased-donor liver transplant recipients

BACKGROUND

: Due to ongoing organ donor shortage, an increasing number of adult live-donor liver transplants (LDLT) are being performed. The aims of this study were to compare the incidence of ACR between recipients of live- and deceased-donor liver transplants, and to note any differences in ACR among related and unrelated living-donor recipients.

METHODS

: Sixty-four adults undergoing LDLT between 1998-2001 were closely matched with a deceased recipient. Statistical comparisons in ACR between the live- and deceased-donor groups were based on the differences between the ACR rates of each LDLT patient and the corresponding matched deceased recipient. Analyses were performed separately for pairs in which the living donor was not related to the recipient, was a nonsibling relative, or was a sibling.

RESULTS

: Live- and deceased-donor recipients underwent a similar number of liver biopsies. In all, 16/50 (32%) of the biopsied LDLT patients had ACR compared to 36/49 (73%) of the deceased-donor recipients. ACR rates of living donors and their deceased-donor matches did not differ significantly for the unrelated living donors, but did differ for the nonsibling related (P=0.03) and the sibling LDLT (P=0.03). The results were similar when comparing rates of high-degree ACR for unrelated, nonsibling related, and sibling pairs. High-degree ACR differences in the sibling LDLT group were significantly greater than in the nonsibling group (P=0.05).

CONCLUSIONS

: Rates of ACR and high-degree ACR are decreased in living-related liver transplant recipients. This difference is likely genetically related as ACR rates are lower in recipient-donor pairs of increasing genetic similarity.

Adult live donor liver transplantation

The increasing awareness of liver diseases and their early detection have led to an increase in the number of transplant waiting list candidates over the past decade. This need has not been matched by the actual number of orthotopic liver transplantations performed. Live donor liver transplantation (LDLT) is an innovative surgical technique intended to expand the available organ donor pool. Although LDLT offers definite advantages to the recipient, it offers none to the donor except for the possibility of psychological well-being. Clinical research studies aimed at the prospective collection of data for donors and recipients need to be conducted.

Outcome analysis of cirrhotic patients undergoing chest tube placement

OBJECTIVES

Patients with cirrhosis can acquire pulmonary conditions that may or may not be related to their illness. Although posing a greater risk for complications, chest tubes are sometimes placed as treatment for hepatic hydrothorax and other pulmonary conditions. The aim of this study was to analyze the outcomes of chest tube placement in cirrhotic patients.

METHODS

A retrospective analysis was performed of 59 adults with cirrhosis undergoing chest tube placement. Variables that were investigated included reason for chest tube placement, complications developing while having the tube in place, and outcome.

RESULTS

The 59 subjects were classified as having Child-Turcotte-Pugh (CTP) class A cirrhosis (n = 3), CTP class B cirrhosis (n = 31), and CTP class C cirrhosis (n = 25). Indications for having a chest tube placed were hepatic hydrothorax (n = 24), pneumothorax (n = 9), empyema (n = 8), video-assisted thoracoscopy (VAT) [n = 7], non-VAT (n = 5), and hemothorax (n = 3). The CTP class A subjects had their chest tubes removed without further complications early in the course, and were excluded from further statistical analysis. Twenty-five subjects (42%) had significant pleural effusions requiring chest tube placement. Among the CTP class B and class C subjects, the median duration with chest tube in place was 5.0 days (range, 1 to 53 days). Serum total bilirubin levels, presence of portosystemic encephalopathy, and CTP C classification were predictors of mortality. Mortalities were seen in 5 of 31 CTP class B subjects (16%), and 10 of 25 CTP class C subjects (40%). The tubes were successfully removed in a total of 39 subjects (66%) with no further procedure. Forty-seven subjects (80%) acquired one or more of the following complications: renal dysfunction, electrolyte imbalances, and infection.

CONCLUSIONS

When placed for all indications, chest tubes may be successfully removed in the majority of cirrhotic patients. However, a third of all patients still die with the chest tube still in place. Failure to remove the chest tube increases mortality in patients with increasing severity of liver disease.

Survival and risk of recidivism in methadone-dependent patients undergoing liver transplantation

Cirrhosis resulting from hepatitis C virus is presently the most common indication for liver transplantation (OLT) in the United States. A number of U.S. transplant centers require cirrhotics who are using methadone to discontinue it before proceeding with OLT. We sought to examine the outcomes of those patients who had undergone OLT at the Mount Sinai Medical Center. A retrospective chart review of 36 subjects on methadone maintenance treatment (MMT), and off heroin, at the time of OLT was performed. The median daily methadone dose pre-OLT was 50 mg. Post-OLT, there was an increase in methadone dose in 15 subjects, a decrease in four subjects, and no dose change in 17 subjects. Four subjects had documented single episodes of intravenous drug use post-OLT; only one subject had a dose change after the event. Patient and graft survival rates were comparable to the national average. There was no significant difference in post-OLT outcome in patients on MMT when compared with the general population. The few episodes of drug relapse were not related to changes in the methadone dose. Efforts should be made to allow methadone-using cirrhotics better access to OLT without regard to methadone dosage.

Endoscopic diagnosis of bleeding Meckel's diverticulum in a multivisceral transplant recipient

Small bowel transplantation has become a life-saving procedure for patients with intestinal failure who fail conventional therapy. Meckel's diverticulum is a rare cause of occult gastrointestinal bleeding that has not been reported in patients receiving intestinal allografts. We report a case in which transplantation of an asymptomatic Meckel's diverticulum as part of a multivisceral allograft led to intestinal bleeding requiring surgical intervention. Endoscopy identified the actual bleeding diverticulum. Diverticulectomy at the time of transplant was not performed due to the difficult operative course, and the need for frequent surveillance ileoscopy, which would be performed across a fresh intestinal anastomosis. The patient underwent resection of the diverticulum, along with 40 cm of ileum, and did not experience further bleeding.

Syngeneic living-donor liver transplantation without the use of immunosuppression

Transplantation between monozygotic twins has been successfully performed using the kidney, small intestine, and pancreas. Identical HLA matching has enabled these individuals to be transplanted without the need for immunosuppressive medication. Liver transplantation without immunosuppression would lessen the risk of recurrent viral hepatitis and eliminate much of the morbidity associated with long-term use of immunosuppressive medication. Living-donor liver transplantation (LDLT) has been performed with increasing success in recent years without an opportunity arising to use a monozygotic twin as a donor. We report 2 cases of LDLT between identical twins wherein perfect haploidentity has allowed these recipients to be transplanted without the need for immunosuppression. Although HLA matched genotypically, there may be differences in anatomy between donor and recipient. Mild liver chemistry test abnormalities may occur after transplant despite the absence of immunosuppression.

Helicobacter pylori decreases gastric mucosal glutathione

Activation of oxidative stress pathways may contribute to gastric epithelial damage and mutagenesis caused by Helicobacter pylori. We measured the effect of H. pylori on the concentrations of reduced glutathione (GSH), an important endogenous defense against oxidant damage, in gastric epithelial cells in vivo and in vitro. GSH concentrations were significantly lower in gastric biopsies from 19 H. pylori-infected patients than 38 normal controls, and correlated inversely with inflammatory cell numbers. In vitro, H. pylori initially increased GSH levels in AGS cells, but subsequently depleted intracellular GSH stores completely after 24 h. No GSH was detected in H. pylori. Our data suggest that diminished GSH levels with H. pylori colonization of the gastric mucosa may be due to a direct effect of the bacterium as well as through the associated inflammatory response.

Human right and left colon differ in epithelial cell apoptosis and in expression of Bak, a pro-apoptotic Bcl-2 homologue

BACKGROUND

Propensity to colonic neoplasia differs between the right and left colon.

AIMS

To examine whether this difference may be related to regional differences in epithelial apoptosis, in expression of a proapoptotic regulatory protein, Bak, and in proliferation.

PATIENTS

Individuals with no history of colorectal neoplasia.

METHODS

Archival blocks of colorectal tissues were immunostained for proliferating cells (antibody to Ki-67 antigen), and Bak expression (polyclonal antiserum). Cells containing DNA strand breaks, a marker of apoptosis, were identified by terminal deoxyuridine nucleotidyl nick end labelling (TUNEL).

RESULTS

There were fewer TUNEL positive epithelial cells in the right colon (mean 1.2 (SE 0.1)% of all epithelial cells) than the left colon (2.2 (0.1)%, p<0.0001) or rectum (2.2 (0.3)%, p<0.05). Bak expression was less common in the right colon (mean 46 (2.3)% of epithelial cells immunoreactive) than the left colon (66 (2.7)%, p<0.0001), or rectum (67 (2.3)%, p<0.001). Bak expression and TUNEL positivity were highly positively correlated (p<0.0001). In contrast to apoptosis, mean whole crypt proliferation labelling index was similar throughout the colorectum (right colon: 15.6 (3.2)%; left colon: 13. 5 (1.2)%; rectum: 13.3 (2.3)%).

CONCLUSION

The percentage of proliferating colonic epithelial cells is constant throughout the colon, but fewer epithelial cells undergo Bak mediated apoptosis in the right than in the left colon or rectum. This suggests that colonocytes may be lost by methods other than apoptosis in the right colon.