Long-term outcomes of vedolizumab in inflammatory bowel disease: the Swedish prospective multicentre SVEAH extension study

Background

Real-world data on long-term outcomes of vedolizumab (VDZ) are scarce.

Objective

To assess long-term outcomes (up to 3 years) of VDZ in treating inflammatory bowel disease (IBD).

Design

A nationwide, prospective multicentre extension of a Swedish observational study on VDZ assessing Effectiveness And Healthcare resource utilization in patients with IBD (SVEAH).

Methods

After re-consent, data of patients with Crohn's disease (CD) (n = 68) and ulcerative colitis (UC) (n = 46) treated with VDZ were prospectively recorded using an electronic case report form integrated with the Swedish IBD Register (SWIBREG). The primary outcome was clinical remission (defined as Harvey-Bradshaw Index ⩽4 in CD and partial Mayo score ⩽2 in UC) at 104 and 156 weeks in patients with a response and/or remission 12 weeks after starting VDZ. Secondary outcomes included health-related quality of life (HRQoL) and biochemical outcomes.

Results

VDZ continuation rates were high at weeks 104 and 156, 88% and 84%, respectively, for CD and 87% and 78%, respectively, for UC. Of the 53 CD patients with a response/remission at 12 weeks, 40 (75%) patients were in remission at 104 weeks and 42 (79%) patients at 156 weeks. For UC, these numbers were 25/31 (81%) and 22/31 (71%), respectively. Improvements were seen in the Short Health Scale (p < 0.01 for each dimension; CD, n = 51; UC, n = 33) and the EuroQol 5-Dimensions, 5-levels index value (p < 0.01; CD, n = 39; UC, n = 30). Median plasma-C-reactive protein concentrations (mg/L) decreased from 5 at baseline to 4 in CD (p = 0.01, n = 53) and from 5 to 4 in UC (p = 0.03, n = 34) at 156 weeks. Correspondingly, median faecal-calprotectin (µg/g) decreased from 641 to 114 in CD patients (p < 0.01, n = 26) and from 387 to 37 in UC patients (p = 0.02, n = 17).

Conclusion

VDZ demonstrated high continuation rates and was associated with improvements in clinical outcomes, HRQoL measures and inflammatory markers at 2 and 3 years after treatment initiation in this prospective national SVEAH extension study.

Registration

ENCePP registration number: EUPAS22735.

Withdrawal of infliximab or concomitant immunosuppressant therapy in patients with Crohn's disease on combination therapy (SPARE): a multicentre, open-label, randomised controlled trial

BACKGROUND

The combination of infliximab and immunosuppressant therapy is a standard management strategy for patients with Crohn's disease. Concerns regarding the implications of long-term combination therapy provided the rationale for a formal clinical trial of treatment de-escalation. Our aim was to compare the relapse rate and the time spent in remission over 2 years between patients continuing combination therapy and those stopping infliximab or immunosuppressant therapy.

METHODS

This multicentre, open-label, randomised controlled trial was performed in 64 hospitals in seven countries in Europe and Australia. Adult patients with Crohn's disease in steroid-free clinical remission for more than 6 months, on combination therapy of infliximab and immunosuppressant therapy for at least 8 months were randomly assigned (1:1:1) to either continue combination therapy (combination group), discontinue infliximab (infliximab withdrawal group), or discontinue immunosuppressant therapy (immunosuppressant withdrawal group). Randomisation was stratified according to disease duration before start of first anti-TNF treatment (≤2 or >2 years), failure of immunosuppressant therapy before start of infliximab, and presence of ulcers at baseline endoscopy. The patient number and group of each stratum were assigned by a central online randomisation website. Treatment was optimised or resumed in case of relapse in all groups. Participants, those assessing outcomes, and those analysing the data were not masked to group assignment. The coprimary endpoints were the relapse rate (superiority analysis) and time in remission over 2 years (non-inferiority analysis, non-inferiority margin 35 days). Analyses were done on an intention-to-treat basis. This study is registered with ClinicalTrials.gov, NCT02177071, and with EU Clinical Trials Register, EUDRACT 2014-002311-41. The trial was completed in April, 2021.

FINDINGS

Between Nov 2, 2015, and April 24, 2019, 254 patients were screened. Of these, 211 were randomised and 207 were included in the final analysis (n=67 in the combination group, n=71 in the infliximab withdrawal group, and n=69 in the immunosuppressant withdrawal group). 39 patients had a relapse (eight [12%] of 67 in the combination group, 25 [35%] of 71 in the infliximab withdrawal group, six [9%] of 69 in the immunosuppressant withdrawal group). 2-year relapse rates were 14% (95% CI 4-23) in the combination group, 36% (24-47) in the infliximab withdrawal group, and 10% (2-18) in the immunosuppressant withdrawal group (hazard ratio [HR] 3·45 [95% CI 1·56-7·69], p=0·003, for infliximab withdrawal vs combination, and 4·76 [1·92-11·11], p=0·0004, for infliximab withdrawal vs immunosuppressant withdrawal). Of 28 patients who had a relapse and were retreated or optimised according to protocol, remission was achieved in 25 patients (one of two in the combination group, 22 of 23 in the infliximab withdrawal group, and two of three in the immunosuppressant withdrawal group). The mean time spent in remission over 2 years was 698 days (95% CI 668-727) in the combination group, 684 days (651-717) in the infliximab withdrawal group, and 706 days (682-730) in the immunosuppressant withdrawal group. The difference in restricted mean survival time in remission was -14 days (95% CI -56 to 27) between the infliximab withdrawal group and the combination group and -22 days (-62 to 16) between the infliximab withdrawal group and the immunosuppressant withdrawal group. The 95% CIs contained the non-inferiority threshold (-35 days). We recorded 31 serious adverse events, in 20 patients, with no difference in frequency between groups. The most frequent serious adverse events were infections (four in the combination group, two in the infliximab withdrawal group, and one in the immunosuppressant withdrawal group) and Crohn's disease exacerbation (three in the combination group, four in the infliximab withdrawal group, and one in the immunosuppressant withdrawal group). No death nor malignancy was recorded.

INTERPRETATION

In patients with Crohn's disease in sustained steroid-free remission under combination therapy with infliximab and immunosuppressant therapy, withdrawal of infliximab should only be considered after careful assessment of risks and benefits for each patient, whereas withdrawal of immunosuppressant therapy could generally represent a preferable strategy when considering treatment de-escalation.

FUNDING

European Union's Horizon 2020.

Clinical effectiveness of golimumab in ulcerative colitis: a prospective multicentre study based on the Swedish IBD Quality Register, SWIBREG

OBJECTIVES

Clinical trials demonstrated that golimumab is effective in anti-TNF naïve patients with ulcerative colitis. We aimed to assess the clinical effectiveness of golimumab in a real-world setting.

MATERIALS AND METHODS

This was a prospective cohort study, conducted at 16 Swedish hospitals. Data were collected using an electronic case report form. Patients with active ulcerative colitis, defined as Mayo endoscopic subscore ≥2 were eligible for inclusion. The primary outcomes were clinical effectiveness at 12 weeks and 52 weeks, i.e. response (defined as a decrease in Mayo score by ≥3 points or 30% from baseline) and remission (defined as a Mayo score of ≤2 with no individual subscores >1).

RESULTS

Fifty patients were included. At study entry, 70% were previously exposed to anti-TNF, 16% to vedolizumab, and 96% to immunomodulators. The 12 and 52-week drug continuation rates were 37/50 (74%) and 23/50 (46%), respectively. The 12-week response rate was 14/50 (28%), the remission rate, 8/50 (16%) and the corresponding figures at week 52 were 13/50 (26%) and 10/50 (20%). Among patients who continued golimumab, the median Mayo score decreased from 7 (6-9) at baseline to 1 (0-5) at 52 weeks (p < .01) and the faecal calprotectin decreased from 862 (335-1759) µg/g to 90 (34-169) µg/g (p < .01). Clinical response at week 12 was highly predictive of clinical remission at week 52 (adjusted OR: 73.1; 95% CI: 4.5‒1188.9).

CONCLUSIONS

The majority of golimumab treated patients represented a treatment refractory patient-group. Despite this, our results confirm that golimumab is an effective therapy in ulcerative colitis.

Real-world effectiveness of vedolizumab in inflammatory bowel disease: week 52 results from the Swedish prospective multicentre SVEAH study

BACKGROUND

Prospectively and systematically collected real-world data on vedolizumab are scarce. We aimed to assess the long-term clinical effectiveness of vedolizumab in inflammatory bowel disease (IBD).

METHODS

This study was a prospective, observational, multicentre study. Overall, 286 patients with active IBD were included (Crohn's disease, n = 169; ulcerative colitis, n = 117). The primary outcomes were clinical response at week 12 and clinical remission at week 52, based on the Harvey Bradshaw Index and the partial Mayo Clinic score. Secondary outcomes included clinical remission at week 12, clinical response at week 52, corticosteroid-free clinical remission at week 52, changes in biochemical measures, and health-related quality of life (HRQoL).

RESULTS

At baseline, 88% of the patients were exposed to anti-TNF and 41% of the patients with Crohn's disease had undergone ⩾1 surgical resection. At week 12, clinical response was 27% and remission 47% in Crohn's disease; corresponding figures in ulcerative colitis were 52% and 34%. Clinical response, remission and corticosteroid-free remission at week 52 were 22%, 41% and 40% in Crohn's disease and 49%, 47% and 46% in ulcerative colitis, respectively. A statistically significant decrease in median faecal-calprotectin and C-reactive protein was observed at 12 and 52 weeks in patients with Crohn's disease and ulcerative colitis. The HRQoL measures Short Health Scale and EuroQol 5-Dimensions improved in both Crohn's disease and ulcerative colitis patients (p < 0.001). Clinical disease activity at baseline was inversely associated with clinical remission at week 52.

CONCLUSION

Vedolizumab proved effective for the treatment of refractory IBD in clinical practice.

Deep Remission at 1 Year Prevents Progression of Early Crohn's Disease

BACKGROUND & AIMS

We investigated the effects of inducing deep remission in patients with early Crohn's disease (CD).

METHODS

We collected follow-up data from 122 patients (mean age, 31.2 ± 11.3 y) with early, moderate to severe CD (median duration, 0.2 years; interquartile range, 0.1-0.5) who participated in the Effect of Tight Control Management on CD (CALM) study, at 31 sites, representing 50% of the original CALM patient population. Fifty percent of patients (n = 61) were randomly assigned to a tight control strategy (increased therapy based on fecal level of calprotectin, serum level of C-reactive protein, and symptoms), and 50% were assigned to conventional management. We categorized patients as those who were vs were not in deep remission (CD endoscopic index of severity scores below 4, with no deep ulcerations or steroid treatment, for 8 or more weeks) at the end of the follow-up period (median, 3.02 years; range, 0.05-6.26 years). The primary outcome was a composite of major adverse outcomes that indicate CD progression during the follow-up period: new internal fistulas or abscesses, strictures, perianal fistulas or abscesses, or hospitalization or surgery for CD. Kaplan-Meier and penalized Cox regression with bootstrapping were used to compare composite rates between patients who achieved or did not achieve remission at the end of the follow-up period.

RESULTS

Major adverse outcomes were reported for 34 patients (27.9%) during the follow-up period. Significantly fewer patients in deep remission at the end of the CALM study had major adverse outcomes during the follow-up period (P = .01). When we adjusted for potential confounders, deep remission (adjusted hazard ratio, 0.19; 95% confidence interval, 0.07-0.31) was significantly associated with a lower risk of major adverse outcome.

CONCLUSIONS

In an analysis of follow-up data from the CALM study, we associated induction of deep remission in early, moderate to severe CD with decreased risk of disease progression over a median time of 3 years, regardless of tight control or conventional management strategy.

Short and long-term efficacy of adalimumab in ulcerative colitis: a real-life study

Objective: Randomized controlled trials have shown the effectiveness of Adalimumab in ulcerative colitis. However, real-life data is scarce. We aimed to assess the effectiveness and predictive factors of effectiveness in a large Swedish cohort.Methods: Retrospective capture of data from local registries at five Swedish IBD centers. Clinical response and remission rates were assessed at three months after starting adalimumab treatment and patients were followed until colectomy or need for another biological. Bio-naive patients were compared to bio experienced patients. Factors associated with short term responses were assessed using logistic regression model. Failure on drug was assessed using a Cox proportional hazards regression model.Results: 118 patients (59 males, 59 females) with median age 34.4 years (IQR 27.0-51.4) were included. Median disease duration was 4.3 years (IQR 2.0-9.0) and follow-up 1.27 years (IQR 0.33-4.1). A clinical corticosteroid-free remission was achieved by 38/118 (32.2%) and response by 91/118 (77%) after three months. CRP >3 mg/l at baseline was predictive of short-term failure to reach corticosteroid-free remission. Factors associated with survival on the drug were male gender, CRP <3 mg/l and absence of primary sclerosing cholangitis. Patients >42 years of age at diagnosis were more likely to respond to adalimumab and remain on treatment compared to patients <20 years.Conclusions: An elevated CRP-level, primary sclerosing cholangitis and female gender were predictors of treatment failure. In contrast older age at diagnosis was a predictor of short-term clinical response and drug survival. Prior infliximab failure, regardless of cause, did not influence the outcome of adalimumab treatment.

The Cost-effectiveness of Biological Therapy Cycles in the Management of Crohn's Disease

OBJECTIVES

To examine the cost-effectiveness of continued treatment for patients with moderate-severe Crohn's disease in clinical remission, with a combination of anti-tumour necrosis factor alpha [anti-TNFα] [infliximab] and immunomodulator therapy compared with two different withdrawal strategies: [1] withdrawal of the anti-TNFα therapy; and [2] withdrawal of the immunomodulator therapy, respectively.

METHODS

A decision-tree model was constructed mimicking three treatment arms: [1] continued combination therapy with infliximab and immunomodulator; [2] withdrawal of infliximab; or [3] withdrawal of the immunomodulator. Relapses in each arm are managed with treatment intensification and re-institution of the de-escalated drug according to a prespecified algorithm. State-dependent relapse risks, remission probabilities, and quality of life weights were collected from previous published studies.

RESULTS

Combination therapy was less costly and more efficient than the withdrawal of the immunomodulator, and more costly and more efficient than withdrawal of infliximab. Whether or not combination therapy is cost-effective, compared with the alternatives, depends primarily on current pharmaceutical prices and the willingness-to-pay per additional quality-adjusted life-year [QALY].

CONCLUSIONS

Combination therapy using a combination of anti-TNFα [infliximab] and an immunomodulator is cost-effective in the treatment of Crohn's disease compared with treatment cycles in which the immunomodulator is withdrawn. Combination treatment is cost-effective compared with treatment cycles in which infliximab is withdrawn, at prices of infliximab below€192/100 mg, given a willingness-to-pay threshold at€49 020 [Sweden] per additional QALY.

Switching from originator infliximab to the biosimilar CT-P13 in 313 patients with inflammatory bowel disease

BACKGROUND

As the patents of originator biologics are expiring, biosimilar versions are becoming available for the treatment of inflammatory bowel disease (IBD). However, published switch studies of the first infliximab biosimilar, CT-P13, have delivered ambiguous results that could be interpreted as showing a trend towards inferior effectiveness in Crohn's disease (CD) compared with ulcerative colitis (UC). The aim of this study was to investigate the effectiveness and safety of switching IBD patients from treatment with Remicade to CT-P13.

METHODS

In this prospective observational cohort study, all adult IBD patients on Remicade treatment, at four hospitals, were switched to CT-P13. The primary endpoint was change in clinical disease activity at 2, 6, and 12 months after the switch. Secondary endpoints were subgroup analyses of patients with and without concomitant immunomodulators; changes in biomarkers, quality of life, drug trough levels and anti-drug antibodies (ADAbs); and adverse events.

RESULTS

A total of 313 IBD patients were switched (195 CD; 118 UC). There were no significant changes in clinical disease activity, quality of life, biomarkers (except a small but significant increase in albumin in CD) including F-calprotectin, drug trough levels, or proportion of patients in remission. Disease worsening rates were 14.0% for CD and 13.8% for UC; and 2.7% developed ADAbs and 2.2% developed serious adverse events.

CONCLUSIONS

This is the largest study of switched IBD patients published to date, and it demonstrates that switching from Remicade to CT-P13 may be done with preserved therapeutic effectiveness and safety in both CD and UC.

Long-term effectiveness of vedolizumab in inflammatory bowel disease: a national study based on the Swedish National Quality Registry for Inflammatory Bowel Disease (SWIBREG)

OBJECTIVES

Clinical trials have demonstrated the efficacy of vedolizumab in inflammatory bowel disease (IBD). However, these findings may not reflect the clinical practice. Therefore, we aimed to describe a vedolizumab-treated patient population and assess long-term effectiveness.

MATERIALS AND METHODS

Patients initiating vedolizumab between 1 June 2014 and 30 May 2015 were identified through the Swedish National Quality Registry for IBD. Prospectively collected data on treatment and disease activity were extracted. Clinical remission was defined as Patient Harvey Bradshaw index <5 in Crohn's disease (CD) and Patient Simple Clinical Colitis Activity index <3 in ulcerative colitis (UC).

RESULTS

Two-hundred forty-six patients (147 CD, 92 UC and 7 IBD-Unclassified) were included. On study entry, 86% had failed TNF-antagonist and 48% of the CD patients had undergone ≥1 surgical resection. After a median follow-up of 17 (IQR: 14-20) months, 142 (58%) patients remained on vedolizumab. In total, 54% of the CD- and 64% of the UC patients were in clinical remission at the end of follow-up, with the clinical activity decreasing (p < .0001 in both groups). Faecal-calprotectin decreased in CD (p < .0001) and in UC (p = .001), whereas CRP decreased in CD (p = .002) but not in UC (p = .11). Previous anti-TNF exposure (adjusted HR: 4.03; 95% CI: 0.96-16.75) and elevated CRP at baseline (adjusted HR: 2.22; 95% CI: 1.10-4.35) seemed to be associated with discontinuation because of lack of response. Female sex was associated with termination because of intolerance (adjusted HR: 2.75; 95% CI: 1.16-6.48).

CONCLUSION

Vedolizumab-treated patients represent a treatment-refractory group. A long-term effect can be achieved, even beyond 1 year of treatment.

Vedolizumab treatment for immune checkpoint inhibitor-induced enterocolitis

Immune checkpoint inhibitors (ICPI), such as ipilimumab [anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4) antibody] and nivolumab or pembrolizumab [anti-programmed cell death protein-1 (PD-1) antibodies], improve survival in several cancer types. Since inhibition of CTLA-4 or PD-1 leads to non-selective activation of the immune system, immune-related adverse events (irAEs) are frequent. Enterocolitis is a common irAE, currently managed with corticosteroids and, if necessary, anti-tumor necrosis factor-α therapy. Such a regimen carries a risk of serious side-effects including infections, and may potentially imply impaired antitumor effects. Vedolizumab is an anti-integrin α4β7 antibody with gut-specific immunosuppressive effects, approved for Crohn’s disease and ulcerative colitis. We report a case series of seven patients with metastatic melanoma or lung cancer, treated with vedolizumab off-label for ipilimumab- or nivolumab-induced enterocolitis, from June 2014 through October 2016. Clinical, laboratory, endoscopic, and histologic data were analyzed. Patients initially received corticosteroids but were steroid-dependent and/or partially refractory. One patient was administered infliximab but was refractory. The median time from onset of enterocolitis to start of vedolizumab therapy was 79 days. Following vedolizumab therapy, all patients but one experienced steroid-free enterocolitis remission, with normalized fecal calprotectin. This was achieved after a median of 56 days from vedolizumab start, without any vedolizumab-related side-effects noted. The patient in whom vedolizumab was not successful, due to active ulcerative colitis, received vedolizumab prophylactically. This is the first case series to suggest that vedolizumab is an effective and well-tolerated therapeutic for steroid-dependent or partially refractory ICPI-induced enterocolitis. A larger prospective study to evaluate vedolizumab in this indication is warranted.

Long-term outcome of infliximab treatment in chronic active ulcerative colitis: a Swedish multicentre study of 250 patients

BACKGROUND

Real-life long-term data on infliximab treatment in ulcerative colitis are limited.

AIM

To study the long-term efficacy and safety of infliximab in chronic active ulcerative colitis and possible predictors of colectomy and response were also examined.

METHODS

A retrospective multi-centre study of infliximab treatment in 250 patients with chronic active ulcerative colitis with inclusion criteria: age ≥18 years, ambulatory treated, steroid-dependent or intolerant and/or immunomodulator refractory or intolerant.

RESULTS

Steroid-free clinical remission was achieved by 123/250 patients (49.2%) at 12 months and in 126/250 patients at a median follow-up of 2.9 years (50.4%). Primary response at 3 months was achieved by 190/250 (76.0%) patients and associated with a high probability of response 168/190 (88.4%) at 12 months and 143/190 (75.3%) at follow-up. Long-term rate of colectomy in primary responders was 6/190 (3.2%) at 12 months and 27/190 (14.2%) at last follow-up. Failure to achieve response at 3 months was associated with a high risk of subsequent colectomy, 29/60 (48.3%) at 12 months and 41/60 (68.3%) at follow-up. Response at 12 months was associated with a low risk of subsequent colectomy, 14/181 (7.7%) compared with non-response 19/34 (55.9%) (P < 0.0001). Non-response at 3 months was an independent predictor of subsequent colectomy (HR = 9.40, 95% CI = 5.10-17.35, P < 0.001). Concomitant azathioprine therapy did not influence outcome in terms of colectomy.

CONCLUSIONS

Long-term efficacy of infliximab treatment in chronic active ulcerative colitis is excellent especially in patients who respond to induction treatment. Conversely, non-response at 3 months predicts a poor outcome, with a high risk of subsequent colectomy.

Low-dose budesonide for maintenance of clinical remission in collagenous colitis: a randomised, placebo-controlled, 12-month trial

OBJECTIVE

This 1-year study aimed to assess low-dose budesonide therapy for maintenance of clinical remission in patients with collagenous colitis.

DESIGN

A prospective, randomised, placebo-controlled study beginning with an 8-week open-label induction phase in which patients with histologically confirmed active collagenous colitis received budesonide (Budenofalk, 9 mg/day initially, tapered to 4.5 mg/day), after which 92 patients in clinical remission were randomised to budesonide (mean dose 4.5 mg/day; Budenofalk 3 mg capsules, two or one capsule on alternate days) or placebo in a 12-month double-blind phase with 6 months treatment-free follow-up. Primary endpoint was clinical remission throughout the double-blind phase.

RESULTS

Clinical remission during open-label treatment was achieved by 84.5% (93/110 patients). The median time to remission was 10.5 days (95% CI (9.0 to 14.0 days)). The maintenance of clinical remission at 1 year was achieved by 61.4% (27/44 patients) in the budesonide group versus 16.7% (8/48 patients) receiving placebo (treatment difference 44.5% in favour of budesonide; 95% CI (26.9% to 62.7%), p<0.001). Health-related quality of life was maintained during the 12-month double-blind phase in budesonide-treated patients. During treatment-free follow-up, 82.1% (23/28 patients) formerly receiving budesonide relapsed after study drug discontinuation. Low-dose budesonide over 1 year resulted in few suspected adverse drug reactions (7/44 patients), all non-serious.

CONCLUSIONS

Budesonide at a mean dose of 4.5 mg/day maintained clinical remission for at least 1 year in the majority of patients with collagenous colitis and preserved health-related quality of life without safety concerns. Treatment extension with low-dose budesonide beyond 1 year may be beneficial given the high relapse rate after budesonide discontinuation.

TRIAL REGISTRATION NUMBERS

http://www.clinicaltrials.gov (NCT01278082) and http://www.clinicaltrialsregister.eu (EudraCT: 2007-001315-31).

Enhanced colonic tumorigenesis in alkaline sphingomyelinase (NPP7) knockout mice

Intestinal alkaline sphingomyelinase (alk-SMase) generates ceramide and inactivates platelet-activating factor (PAF) and was previously suggested to have anticancer properties. The direct evidence is still lacking. We studied colonic tumorigenesis in alk-SMase knockout (KO) mice. Formation of aberrant crypt foci (ACF) was examined after azoxymethane (AOM) injection. Tumor was induced by AOM alone, a conventional AOM/dextran sulfate sodium (DSS) treatment, and an enhanced AOM/DSS method. β-Catenin was determined by immunohistochemistry, PAF levels by ELISA, and sphingomyelin metabolites by mass spectrometry. Without treatment, spontaneous tumorigenesis was not identified but the intestinal mucosa appeared thicker in KO than in wild-type (WT) littermates. AOM alone induced more ACF in KO mice but no tumors 28 weeks after injection. However, combination of AOM/DSS treatments induced colonic tumors and the incidence was significantly higher in KO than in WT mice. By the enhanced AOM/DSS method, tumor number per mouse increased 4.5 times and tumor size 1.8 times in KO compared with WT mice. Although all tumors were adenomas in WT mice, 32% were adenocarcinomas in KO mice. Compared with WT mice, cytosol expression of β-catenin was significantly increased and nuclear translocation in tumors was more pronounced in KO mice. Lipid analysis showed decreased ceramide in small intestine and increased sphingosine-1-phosphate (S1P) in both small intestine and colon in nontreated KO mice. PAF levels in feces were significantly higher in the KO mice after AOM/DSS treatment. In conclusion, lack of alk-SMase markedly increases AOM/DSS-induced colonic tumorigenesis associated with decreased ceramide and increased S1P and PAF levels.

Changes of activity and isoforms of alkaline sphingomyelinase (nucleotide pyrophosphatase phosphodiesterase 7) in bile from patients undergoing endoscopic retrograde cholangiopancreatography

Background

Alkaline sphingomyelinase (NPP7) is an ecto-enzyme expressed in intestinal mucosa, which hydrolyses sphingomyelin (SM) to ceramide and inactivates platelet activating factor. It is also expressed in human liver and released in the bile. The enzyme may have anti-tumour and anti-inflammatory effects in colon and its levels are decreased in patients with colon cancer and ulcerative colitis. Active NPP7 is translated from a transcript of 1.4 kb, whereas an inactive form from a 1.2 kb mRNA was found in colon and liver cancer cell lines. While the roles of NPP7 in colon cancer have been intensively studied, less is known about the function and implications of NPP7 in the bile. The present study examines the changes of NPP7 in bile of patients with various hepatobiliary diseases.

Methods

Bile samples were obtained at endoscopic retrograde cholangiopancreatography (ERCP) in 59 patients with gallstone, other benign disease, tumour, and primary sclerosing cholangitis (PSC). The NPP7 activity was determined. The appearance of the 1.4 and 1.2 kb products in the bile was examined by Western blot. The results were correlated to the diseases and also plasma bilirubin and alkaline phosphatase.

Results

NPP7 activity in the tumour group was significantly lower than in the gallstone group (p < 0.05). The activity in the tumour plus PSC group was also lower than in gallstone plus other benign disease group (p < 0.05). Within the tumour group NPP7 activity was lowest in cholangiocarcinoma patients, being only 19% of that in gallstone patients. Bilirubin correlated inversely to NPP7 and was higher in the tumour than in the gallstone group. Western blot identified both the 1.4 kb and the 1.2 kb products in most bile samples. The density ratio for the 1.4/1.2 kb products correlated to NPP7 activity significantly. Two patients (one PSC and one cholangiocarcinoma) lacking NPP7 activity had only the 1.2 kb form in bile.

Conclusion

NPP7 activity and the ratio of 1.4/1.2 kb products in bile are significantly decreased in malignancy, particularly in cholangiocarcinoma. The implications of the finding in diagnosis of cholangiocarcinoma and 1.2 kb product in hepatobiliary diseases require further investigation.

Alkaline sphingomyelinase (NPP7) promotes cholesterol absorption by affecting sphingomyelin levels in the gut: A study with NPP7 knockout mice

We previously showed that dietary sphingomyelin (SM) inhibited cholesterol absorption in animals. The key enzyme hydrolyzing SM in the gut is alkaline sphingomyelinase (alk-SMase, nucleotide pyrophosphatase/phosphodiesterase 7). Here using the fecal dual-isotope ratio method we compared cholesterol absorption in the wild-type (WT) and alk-SMase knockout (KO) mice. The animals were fed an emulsion containing [(14)C]cholesterol and [(3)H]sitosterol. The radioactivities in the lipids of the fecal samples collected 4, 8, and 24 h thereafter were determined, and the ratio of (14)C/(3)H was calculated. We found that the fecal [(14)C]cholesterol recovery in the KO mice was significantly higher than in the WT mice. A maximal 92% increase occurred 8 h after feeding. Recovery of [(3)H]sitosterol did not differ between the two groups. Accordingly, the (14)C-to-(3)H ratio of fecal lipids was 133% higher at 8 h and 75% higher at 24 h in the KO than in the WT mice. Decreased [(14)C]cholesterol was also found in the serum of the KO mice 4 h after feeding. Supplement of SM in the emulsion reduced the differences in fecal [(14)C]cholesterol recovery between the WT and KO mice because of a greater increase of [(14)C]cholesterol recovery in the WT mice. Without treatment, the KO mice had significantly higher SM levels in the intestinal content and feces, but not in the intestinal mucosa or serum. The expression of Niemann-Pick C1 like 1 protein in the small intestine was not changed. In conclusion, alk-SMase is a physiological factor promoting cholesterol absorption by reducing SM levels in the intestinal lumen.

Novel mutation in the KCNJ2 gene is associated with a malignant arrhythmic phenotype of Andersen-Tawil syndrome

BACKGROUND

Andersen-Tawil syndrome (ATS) is a rare inherited multisystem disorder associated with mutations in KCNJ2 and low prevalence of life-threatening ventricular arrhythmias. Our aim was to describe the clinical course of ATS in a family, in which the proband survived aborted cardiac arrest (ACA) and genetic screening revealed a previously unknown mutation (c.271_282del12[p.Ala91_Leu94del]) in the KCNJ2 gene.

METHODS

A cascade family screening was performed in a 5-generation family after identification of the KCNJ2 mutation in the proband. Subsequently, 10 of 21 screened individuals appeared to be mutation carriers (median age 38 [range 10-75] years, 3 female). Mutation carriers underwent clinical examination including biochemistry panel, cardiac ultrasound, Holter ECG, and exercise stress test.

RESULTS

(1) At baseline, 2 patients had survived ACA, 3 had syncope or presyncopal attacks, and 2 reported palpitations. Exercise-induced nonsustained bidirectional ventricular tachycardia was documented in 4 patients, 2 received implantable cardioverter-defibrillators (ICD) for primary prevention and 2 for secondary prevention. (2) During follow-up, 1 primary prevention and 1 secondary prevention patient received in total 4 adequate ICD shocks. Life-threatening ventricular arrhythmias were documented during childhood in 5 of 10 mutation carriers. (3) All mutation carriers presented with characteristic mild dysmorphic features. Only 1 patient suffered from periodic paralysis. All had normal serum potassium level at repeated assessments and none had any other extracardiac disease manifestation.

CONCLUSION

Our findings suggest that the novel KCNJ2 mutation is associated with a predominantly cardiac phenotype of Andersen-Tawil syndrome with high propensity to life-threatening ventricular arrhythmias presenting from childhood and young adulthood.

Infliximab as rescue therapy in hospitalised patients with steroid-refractory acute ulcerative colitis: a long-term follow-up of 211 Swedish patients

BACKGROUND

Rescue therapy with infliximab (IFX) has been proven effective in a steroid-refractory attack of ulcerative colitis (UC). The long-term efficacy is not well described.

AIM

To present a retrospective study of IFX as rescue therapy in UC. Primary end points were colectomy-free survival at 3 and 12 months.

METHODS

In this multicentre study, 211 adult patients hospitalised between 1999 and 2010 received IFX 5 mg/kg as rescue therapy due to a steroid-refractory, moderate-to-severe attack of UC. Exclusion criteria were duration of current flare for >12 weeks, corticosteroid treatment for >8 weeks before hospitalisation, previous IFX therapy or Crohn's disease.

RESULTS

Probability of colectomy-free survival at 3 months was 0.71 (95% CI, 0.64-0.77), at 12 months 0.64 (95% CI, 0.57-0.70), at 3 years 0.59 (95% CI, 0.52-0.66) and at 5 years 0.53 (95% CI, 0.44-0.61). Steroid-free, clinical remission was achieved in 105/211 (50%) and 112/209 (54%) patients at 3 and 12 months respectively. Of 75 colectomies during the first year, 48 (64%) were carried out during the first 14 days, 13 (17%) on days 15-90 and 14 (19%) between 3 and 12 months. There were three (1.4%) deaths during the first 3 months.

CONCLUSIONS

Infliximab is an effective rescue treatment, both short- and long-term, in a steroid-refractory attack of UC. Most IFX failures underwent surgery during the first 14 days, which calls for studies on how to optimise induction treatment with IFX. Serious complications, including mortality, were rare.

Infliximab or cyclosporine as rescue therapy in hospitalized patients with steroid-refractory ulcerative colitis: a retrospective observational study

BACKGROUND

Cyclosporine (CsA) or infliximab (IFX) are used as rescue therapies in steroid-refractory, severe attacks of ulcerative colitis (UC). There are no data comparing the efficacy of these two alternatives.

METHODS

Outcome of rescue therapy was retrospectively studied in two cohorts of patients hospitalized due to steroid-refractory moderate to severe UC: 1) a Swedish-Danish cohort (n = 49) treated with a single infusion of IFX; 2) an Austrian cohort (n = 43) treated with intravenous CsA. After successful rescue therapy, maintenance immunomodulator treatment was given to 27/33 (82%) of IFX patients and to 31/40 (78%) of CsA patients. Endpoints were colectomy-free survival at 3 and 12 months. Kaplan-Meier and Cox regression models were used to evaluate the association between treatment groups and colectomy.

RESULTS

At 15 days, colectomy-free survival in the IFX cohort was 36/49 (73%) versus 41/43 (95%) in the CsA cohort (P = 0.005), at 3 months 33/49 (67%) versus 40/43 (93%) (P = 0.002), and at 12 months 28/49 (57%) versus 33/43 (77%) (P = 0.034). After adjusting for potential confounding factors, Cox regression analysis yielded adjusted hazard ratios for risk of colectomy in IFX-treated patients of 11.2 (95% confidence interval [CI] 2.4-53.1, P = 0.002) at 3 months and of 3.0 (95% CI 1.1-8.2, P = 0.030) at 12 months in comparison with CsA-treated patients. There were no opportunistic infections or mortality.

CONCLUSIONS

Colectomy frequencies were significantly lower after rescue therapy with CsA than with a single infusion of IFX both at 3 and 12 months' follow-up. The superiority of CsA was seen principally during the first 15 days.

Thrombotic occlusion of all left coronary branches in a young woman with severe ulcerative colitis

Background. The thrombosis risk is increased in active ulcerative colitis. The limited number of reported complications have predominantly been cerebrovascular but other vessel territories may also be affected. Patient. During a severe attack of ulcerative colitis a 37-year-old woman suffered occlusion of all left coronary artery branches. Serial angiographies showed progressive recanalisation of the coronary arteries during anticoagulation, but no atherosclerotic stenosis. The cause of infarction was thus considered to be an extensive coronary thrombosis. However, a large battery of blood tests failed to identify any procoagulant abnormality. Conclusion. Evidence is now accumulating that the increased thrombosis risk also may involve the coronary arteries, even in young patients. To the best of our knowledge this is the third reported case of myocardial infarction despite angiographically normal coronary arteries in a patient with active ulcerative colitis. The extent of affected myocardium was in this case exceptionally large.

Clinical trial: colectomy after rescue therapy in ulcerative colitis - 3-year follow-up of the Swedish-Danish controlled infliximab study

BACKGROUND

The long-term efficacy of infliximab as rescue therapy in steroid-refractory ulcerative colitis is not well described.

AIM

To examine the long-term efficacy of infliximab as a rescue therapy through a 3-year follow-up of a previous placebo-controlled trial of infliximab in acute steroid-refractory ulcerative colitis.

METHOD

In the original study, 45 patients were randomized to a single infusion of infliximab 5 mg/kg or placebo, and at 3 months, 7/24 patients given infliximab were operated vs. 14/21 patients given placebo. Three years or later, patients were asked to participate in a clinical follow-up.

RESULTS

Another seven patients underwent colectomy during follow-up: five in the infliximab group and two in the placebo group. After 3 years, a total of 12/24 (50%) patients given infliximab and 16/21 (76%) given placebo (P = 0.012) had a colectomy. None of eight patients in endoscopic remission at 3 months later had a colectomy compared with 7/14 (50%) patients who were not in remission (P=0.02). There was no mortality.

CONCLUSION

The benefit of rescue therapy with infliximab in steroid-refractory acute ulcerative colitis remained after 3 years. The main advantage of infliximab treatment occurred during the first 3 months, whereas subsequent colectomy rates were similar in the two groups. Mucosal healing at 3 months influenced later risk of colectomy.

Sphingolipids in human ileostomy content after meals containing milk sphingomyelin

BACKGROUND

Sphingomyelin occurs in modest amounts in the diet, in sloughed mucosal cells, and in bile. It is digested by the mucosal enzymes alkaline sphingomyelinase and ceramidase. In humans, alkaline sphingomyelinase is also secreted in bile. The digestion of sphingomyelin is slow and incomplete, which has been linked to the inhibition of cholesterol absorption and colonic carcinogenesis.

OBJECTIVE

We evaluated whether the supply of moderate amounts of milk sphingomyelin increases the exposure of the colon to sphingomyelin and its metabolites.

DESIGN

Two experimental series were performed. In experiment A, we measured the content of sphingomyelin and ceramide in human ileostomy content by HPLC during 8 h after consumption of a test meal containing 250 mg milk sphingomyelin. In experiment B, we measured the molecular species of sphingomyelin and ceramide by HPLC-tandem mass spectrometry after doses of 50, 100, or 200 mg sphingomyelin.

RESULTS

In experiment A, the average increase in ileostomy content of ceramide plus sphingomyelin amounted to 19% of the fed dose of sphingomyelin. In experiment B, the output of C-22:0-sphingomyelin, C-23:0-sphingomyelin, C-24:0-sphingomyelin, and sphingosine increased significantly, and palmitoyl-sphingomyelin increased proportionally less. Outputs and concentrations of palmitoyl-ceramide and sphingosine showed great individual variation, and stearoyl-sphingomyelin and stearoyl-ceramide did not increase after the meals. Although the output of long-chain sphingomyelin species increased significantly, the data indicated that >81% of all measured sphingomyelin species had been digested.

CONCLUSIONS

Humans digest and absorb most of the sphingomyelin in normal diets. The amount of sphingolipid metabolites to which the colon is exposed can, however, be influenced by realistic amounts of dietary sphingomyelin.

Identification of aberrant forms of alkaline sphingomyelinase (NPP7) associated with human liver tumorigenesis

Alkaline sphingomyelinase (alk-SMase) is expressed in the intestine and human liver. It may inhibit colonic tumorigenesis, and loss of function mutations have been identified in human colon cancer. The present study investigates its expression in human liver cancer. In HepG2 liver cancer cells, RT–PCR identified three transcripts with 1.4, 1.2 and 0.4 kb, respectively. The 1.4 kb form is the wild-type cDNA with five translated exons, the 1.2 kb product lacks exon 4 and the 0.4 kb form is a combination of exons 1 and 5. Genomic sequence showed that these aberrant transcripts were products of alternative splicing. Transient expression of the 1.2 kb form showed no alk-SMase activity. In HepG2 cells, the alk-SMase activity is low in monolayer condition and increased with cell polarisation. Coexistence of 1.4 and 1.2 kb forms was also identified in one hepatoma biopsy. GenBank search identified a cDNA clone from human liver tumour, which codes a protein containing full length of alk-SMase plus a 73-amino-acid tag at the N terminus. The aberrant form was translated by an alternative starting codon upstream of the wild-type mRNA. Expression study showed that linking the tag markedly reduced the enzyme activity. We also analysed human liver biopsy samples and found relatively low alk-SMase activity in diseases with increased risk of liver tumorigenesis. In conclusion, expression of alk-SMase is changed in hepatic tumorigenesis, resulting in loss or marked reduction of the enzyme function.

Infliximab as rescue therapy in severe to moderately severe ulcerative colitis: a randomized, placebo-controlled study

BACKGROUND & AIMS

Despite treatment with corticosteroids, severe to moderately severe attacks of ulcerative colitis have a high colectomy rate. We intended to find a rescue therapy other than cyclosporin A, which imposes a high risk of side effects and cyclosporine-related mortality.

METHODS

This was a randomized double-blind trial of infliximab or placebo in severe to moderately severe ulcerative colitis not responding to conventional treatment. Patients were randomized to infliximab/placebo either on day 4 after the initiation of corticosteroid treatment if they fulfilled the index criteria for fulminant ulcerative colitis on day 3 or on day 6-8 if they fulfilled index criteria on day 5-7 for a severe or moderately severe acute attack of ulcerative colitis. Results were analyzed according to the intention-to-treat principle. The primary end point was colectomy or death 3 months after randomization. Secondary end points were clinical and endoscopic remission at that time in patients who did not undergo operation.

RESULTS

Forty-five patients were included (24 infliximab and 21 placebo). No patient died. Seven patients in the infliximab group and 14 in the placebo group had a colectomy (P = .017; odds ratio, 4.9; 95% confidence interval, 1.4-17) within 3 months after randomization. No serious side effects occurred. Three patients in the placebo group required operation for septic complications.

CONCLUSIONS

Infliximab 4-5 mg/kg is an effective and safe rescue therapy in patients experiencing an acute severe or moderately severe attack of ulcerative colitis not responding to conventional treatment.

Identification of two novel sequence variants affecting thiopurine methyltransferase enzyme activity

The polymorphic enzyme thiopurine methyltransferase (TPMT) is involved in the methylation of thiopurines. On comparing the phenotype with the genotype in Swedish patients with inflammatory bowel disease and healthy individuals, we found two discordant cases with low TPMT enzyme activity (0.3 and 0.4 U/ml packed red blood cells (pRBC). Genotyping by pyrosequencing revealed that they carried the nucleotide substitutions 460G>A and 719A>G, giving two possible genotypes (TPMT*1/*3A or TPMT*3B/*3C). DNA sequencing of exon III to X was performed in the patients and their parents. We identified an A>G transition in the start codon (exon III, 1A>G, Met>Val, TPMT*14) in one of the patients and her father (6.3 U/ml pRBC). The mother in this family carried the 460G>A and 719A>G nucleotide substitutions (TPMT*1/*3A; 5.0 U/ml pRBC). In the second family, sequencing revealed a G>A transition in the acceptor splice site in intron VII/exon VIII (IVS7 -1G>A, TPMT*15) in the patient and his mother (6.9 U/ml pRBC). His father was genotyped as TPMT*1/*3A (6.0 U/ml pRBC). Hence, we report the identification of two novel sequence variants, present in highly conserved nucleotide positions of the human TPMT gene, resulting in a loss of enzyme activity.

Bioavailability of selenium from bovine milk as assessed in subjects with ileostomy

OBJECTIVE

To assess the absorption of dietary selenium in humans, especially of milk selenium.

DESIGN

: 1-day meal studies in subjects with ileostomy.

SETTING

Hospital outpatient clinics.

SUBJECTS

Three subjects in the pilot study and nine subjects in the main study (eight men/ four women).

INTERVENTION

Different beverages, 1 l/day, were given in addition to basal diets (soft drink, 1 week; low-fat milk, 3 weeks; fermented low-fat milk, 3 weeks and soft drink, 1 week). Ileostomy effluents were collected during the last 2 days in each of the four periods.

RESULTS

On days when the subjects were given 1 l of low-fat milk, the estimated fractional absorption of total dietary selenium was 65.5 (2.3)% (mean (s.d.), n=18), which was similar to the value when fermented low-fat milk was given (64.1 (3.2)%). However, both the calculated amount of milk selenium absorbed (10.9 (2.4) vs 9.4 (1.7) microg selenium) and its fractional absorption (73.3 (16.1) vs 64.1 (11.2)%, n=18) were significantly higher for milk than for fermented milk.

CONCLUSIONS

Selenium from milk and other sources is well absorbed in subjects with ileostomy. The real absorption may be even higher than the values shown.

Purified intestinal alkaline sphingomyelinase inhibits proliferation without inducing apoptosis in HT-29 colon carcinoma cells

PURPOSE

Sphingomyelin (SM) hydrolysis by sphingomyelinase (SMase) has become an important signalling pathway, with the product ceramide implicated in regulation of cell growth, differentiation and apoptosis. Alkaline SMase is specifically located in the intestinal tract. Marked reductions of the enzyme activity have been found in sporadic colorectal carcinomas and in both adenomas and flat mucosa of patients with familial adenomatous polyposis, indicating an anti-proliferative role in colonic cell growth.

METHODS

We examined the effects of a purified alkaline SMase from rat intestine and a bacterial neutral SMase on cell growth parameters in HT-29 colonic carcinoma cells.

RESULTS

Alkaline SMase was found to inhibit proliferation of HT-29 cells in both dose-dependent and time-dependent manners. The threshold concentration of the enzyme was approximately 2.5 microU/ml, and the maximum effect was obtained at approximately 20 microU/ml, which inhibited the cell growth by 50%. The inhibition occurred rapidly, and maximum effect was reached after 12 h of incubation. Dose-dependent inhibition of DNA synthesis was also demonstrated. The effect of alkaline SMase was preceded and accompanied by increased hydrolysis of SM and production of ceramide. Neutral SMase with equivalent hydrolytic capacity did not inhibit cell growth. Alkaline SMase did not induce apoptosis in HT-29 cells. Alkaline SMase did not inhibit growth of IEC-6 cells.

CONCLUSION

Alkaline SMase, at doses that induce SM hydrolysis, inhibits growth of colon cancer cells. The inhibition is attributed to an anti-proliferative effect rather than an apoptotic effect.

[Sporadic colorectal polyps. Updated guidelines for endoscopic surveillance]

No surveillance is recommended after radical excision of low-risk adenomas (pedunculated adenoma irrespective of size, sessile adenoma < or = 10 mm, number < or = 2. An endoscopic check-up is recommended 3-6 months after radical excision of high-risk adenomas (sessile adenoma > 10 mm, number > or = 3), as well as after excision of a pedunculated or a sessile adenoma with an unclear resection margin. All above is irrespective of histopathological adenoma classification. An endoscopic check-up is recommended 3 months after radical excision of a highly or moderately differentiated malignant polyp with no sign of invasion into blood or lymph vessels and with a maximum invasion depth stage T1-sm1. Surgical resection is necessary if the malignant polyp is poorly differentiated, and/or invades into blood or lymph vessels, and/or is stage T1-sm3, or is excised with unclear resection margins. Treatment for stage T1-sm2 polyps may be individualized. Individuals with low-risk adenomas and a first degree relative with colorectal cancer, individuals having high-risk adenomas or malignant polyps removed, as well as individuals operated on for colorectal cancer should be subjected to colonoscopy after three years and then every fifth year when < or = 75 years of age.

Reduction in alkaline sphingomyelinase in colorectal tumorigenesis is not related to the APC gene mutation

BACKGROUND AND AIMS

The sphingomyelin pathway is an important intracellular mechanism in regulating cell growth. The first step in this pathway is catalysed by sphingomyelinases. Alkaline sphingomyelinase is specifically located in the intestinal tract. Markedly reduced alkaline sphingomyelinase activities have been found in sporadic colorectal tumours and in familial adenomatous polyposis adenomas. Since the adenomatous polyposis coli (APC) gene is mutated in about 80% of sporadic colorectal tumors, and familial adenomatous polyposis is the consequence of a germline mutation of the same gene, we examined whether low alkaline sphingomyelinase activity is linked to APC gene mutations.

PATIENTS AND METHODS

Both germline and sporadic adenomatous polyposis coli gene mutations were studied. Alkaline, neutral, and acid sphingomyelinase activities were measured in the intestinal mucosa and content of multiple intestinal neoplasia mice, a murine model of familial adenomatous polyposis and compared to control mice. Alkaline sphingomyelinase activity was also measured in 11 human rectal tumors with APC gene mutation and compared with 9 control tumors without mutation.

RESULTS

Alkaline, neutral, and acid sphingomyelinase activities were present in the small intestine and colon in both mice types with no differences in hydrolytic capacity or distribution pattern. In sporadic rectal tumors similar alkaline sphingomyelinase activities were identified in tumors with somatic APC gene mutations as in samples without mutations. In the tumors without detectable APC mutations beta-catenin was analyzed, but no mutation was detected.

CONCLUSION

Alkaline sphingomyelinase is not directly linked to adenomatous polyposis coli gene mutations.

Purification, localization, and expression of human intestinal alkaline sphingomyelinase

Sphingomyelin (SM) metabolism in the gut may have an impact on colon cancer development. In this study, we purified alkaline sphingomyelinase (alk-SMase) from human intestinal content, and studied its location in the mucosa, expression in colon cancer, and function on colon cancer cells. The enzyme was purified by a series of chromatographies. The molecular mass of the enzyme is 60 kDa, optimal pH is 8.5, and isoelectric point is 6.6. Under optimal conditions, 1 mg of the enzyme hydrolyzed 11 mM SM per hour. The properties of the enzyme are similar to those of rat intestinal alk-SMase but not to those of bacterial neutral SMase. Immunogold electronmicroscopy identified the enzyme on the microvillar membrane in endosome-like structures and in the Golgi complexes of human enterocytes. The expression and the activity of the enzyme were decreased in parallel in human colon cancer tissues compared with the adjacent normal tissue. The enzyme inhibited DNA biosynthesis and cell proliferation dose dependently and caused a reduction of SM in HT29 cells. Intestinal alk-SMase is localized in the enterocytes, down-regulated in human colon cancer, and may have antiproliferative effects on colon cancer cells.

Chronic colitis is associated with a reduction of mucosal alkaline sphingomyelinase activity

BACKGROUND AND AIMS

The hydrolysis of sphingomyelin (SM) generates key molecules regulating cell growth. Animal cancer studies support an inhibitory role for this pathway in the malignant transformation of the colonic mucosa. The activity of a specific intestinal alkaline sphingomyelinase (SMase), which hydrolyzes SM, is reduced in colorectal tumors. In this study we measured alkaline SMase activity in patients with longstanding colitis and assessed if a reduction can be used as a marker in surveillance of high risk patients.

METHODS

Alkaline SMase activity was measured in 139 colonic biopsies from 34 patients with longstanding, extensive colitis and from 11 controls. Fifteen patients had earlier diagnosis of dysplasia or DNA aneuploidy. Alkaline SMase activity was related to histologic dysplasia and DNA aneuploidy assessed by flow cytometry, patient age, and duration of disease.

RESULTS

Alkaline SMase activity was significantly lower in the patient group with and without dysplasia compared with controls (p = 0.006). In biopsies, an association was not found between alkaline SMase activity, dysplasia, or DNA ploidy. However, alkaline SMase activity decreased with age both in patients and controls (p = 0.008).

CONCLUSIONS

Reduction of alkaline SMase activity seen in colorectal cancer and adenomas is also present in patients with chronic colitis. It is not complementary to dysplasia or DNA-aneuploidy in the identification of high risk patients. The age-associated decrease of alkaline SMase activity seems to be a general phenomenon indicating premature senescence of the mucosa in longstanding colitis.

Sulindac induces apoptosis, inhibits proliferation and activates caspase-3 in Hep G2 cells

BACKGROUND

It has recently been reported that sulindac has an apoptotic effect on KYN-2 cells, an undifferentiated hepatoma cell line. The present work investigates whether sulindac also has an apoptotic effect on well-differentiated hepatoma cells and what its potential mechanism might be.

MATERIALS AND METHODS

Hep G2 cells were treated with sulindac at different concentrations. Apoptosis rate, cell proliferation and 3H-thymidine incorporation were measured. The activities of caspase-3, acid and neutral sphingomyelinase and the changes of sphingomyelin content were also assayed.

RESULTS

Sulindac dose-dependently induced apoptosis in Hep G2 cells; both sulindac sulfone and sulfide had similar effects. The apoptosis was accompanied by an increase of caspase-3 activity and a decrease of cell proliferation and 3H-thymidine incorporation. No significant change could be observed for the activity of sphingomyelinase and sphingomyelin content.

CONCLUSION

Sulindac induces apoptosis and inhibits proliferation in Hep G2 cells. The effect may be mediated by a pathway related to caspase-3 activation but independent of sphingomyelin metabolism

Gender and atrioventricular conduction properties of patients with symptomatic atrioventricular nodal reentrant tachycardia and Wolff-Parkinson-White syndrome

The objective of this study was to delineate the sex distribution and atrioventricular conduction properties in patients with manifest or concealed Wolff-Parkinson-White syndrome (WPW) and atrioventricular nodal reentrant tachycardia (AVNRT). The study comprised 328 patients with AVNRT, 347 with manifest, and 220 with concealed WPW who underwent radiofrequency ablation. A male preponderance was observed in patients with manifest WPW (69%), but not in those with concealed WPW (52%) and female preponderance in AVNRT patients (67%). The PR (166 +/- 25 ms) and AH (88 +/- 20 ms) intervals obtained 30 minutes after ablation in manifest WPW patients were significantly longer than in concealed WPW patients (149 +/- 20, 76 +/- 15 ms, P <.0001). The PR (146 +/- 20 ms) and AH intervals (75 +/- 15 ms) measured before ablation in AVNRT patients were shorter than those obtained before ablation in concealed WPW patients (154 +/- 21, 80 +/- 17 ms, P <.05) and after ablation in manifest WPW patients (P <.0001). The PR interval in AVNRT patients was also shorter than those measured during follow-up in concealed (153 +/- 21 ms, P <.05) and manifest WPW patients (165 +/- 23 ms, P <.0001). The ventriculoatrial block cycle length in AVNRT patients was significantly shorter than in manifest and concealed WPW patients. When age-matched patients were assigned to each group, significant differences in PR interval were observed between men and women (159 +/- 22 vs. 151 +/- 22 ms, P <.0001). Differences in sex distribution exist among patients with manifest and concealed WPW and AVNRT. The atrioventricular conduction properties required for the manifestation of pre-excitation and induction of AVNRT and gender differences in atrioventricular conduction may account for the differences in sex distribution.

Dispersion of atrial repolarization in patients with paroxysmal atrial fibrillation

To study the role of the dispersion of atrial repolarization (DAR) in the genesis of atrial fibrillation (AF), monophasic action potentials (MAP) were recorded simultaneously from a catheter at the high lateral right atrium (HLRA) and a catheter moving around the high, middle and low lateral right atrium (RA) the high, anterior and posterior septal RA and the RA appendage in 15 patients with paroxysmal AF and 15 patients with atrioventricular nodal re-entry tachycardia (AVNRT) or concealed Wolff-Parkinson-White syndrome (WPW) without history of AF. After recordings during sinus rhythm (SR), MAPs were recorded during programmed stimulation (PS) via the HLRA catheter at a drive cycle length (CL) of 500 ms. Thus, MAPs were recorded simultaneously from 2 sites at a time and sequentially from 4 to 12 sites during SR, drive pacing and PS. Taking the MAP at the HLRA as reference, the dispersion of repolarization time (dispersion of RT) and its two components, the dispersions of activation time (dispersion of AT) and MAP duration (dispersion of MAP duration) among the 4 to 12 sites were calculated and taken as parameters of DAR.

RESULTS

During SR and PS, the maximal dispersion of RT was significantly greater in AF than in control patients, 113+/-49 ms vs 50+/-28 ms (P<0.001) and 114+/-56 vs 70+/-43 ms (P<0.05) respectively. The increased dispersion of RT in the AF group was caused by increases in both dispersion of MAP duration and dispersion of AT.

CONCLUSION

During SR and PS, DAR increased in patients with paroxysmal AF due to increases in dispersion of MAP duration and dispersion of AT, which suggests the involvement of both repolarization and conduction disturbances in the development of paroxysmal AF.

Global repolarization sequence of the ventricular endocardium: monophasic action potential mapping in swine and humans

The aim of this study was to evaluate the global sequence of repolarization over the ventricular endocardium. Disturbances in myocardial repolarization are associated with the genesis of arrhythmias. However, little is known about the global sequence of repolarization. Monophasic action potentials (MAPs) were recordedfrom 61 +/- 18 LV and/or RV sites in ten healthy pigs and from 43 +/- 15 LV or RV sites in eight patients using the CARTO system. Local activation time (AT), end-of-repolarization (EOR) time, and MAP duration were calculated and three-dimensional global maps of AT, EOR, and MAP duration constructed. LV maps were obtained from all ten pigs and RV maps from three pigs. Five RV maps and five LV maps were obtained from the eight patients. (1) EOR sequence was recognizable in 12 of 13 pig maps and in all the patient maps. (2) EOR followed the sequence of activation in 12 of 13 pig maps and 8 of 10 patient maps. (3) The longest MAPs were recorded in or near the earliest activation area, and the shortest ones in or near the latest activation area in all the pig maps and in nine often and eight often patient maps, respectively. (4) In all maps, MAP duration and AT were negatively correlated, and EOR and AT positively correlated. In conclusion, repolarization gradients exist over the pig and the human ventricular endocardium. The activation sequence is a determinant for the repolarization sequence. The magnitude of the progressive MAP shortening with progressively later activation, relative to local AT, is a critical factor governing the direction and pattern of the EOR.

Atrioventricular conduction: a determinant for the manifestation of ventricular preexcitation in patients with Wolff-Parkinson-White syndrome

The relation between the atrioventricular conduction properties of the atrioventricular node and the anterograde conduction ability over the accessory pathway in the Wolff-Parkinson-White syndrome has never been studied. Atrioventricular nodal characteristics were studied in 285 patients with manifest and 204 with concealed accessory pathway who underwent radiofrequency ablation, and compared with 146 controls. First and second degree atrioventricular block was observed in 13 (5%) preexcitation patients after ablation, compared with none in concealed accessory pathway (P=0.001) and control patients (P=0.006). The atrial-His intervals in preexcitation patients (88 +/- 20 ms) was significantly longer than in concealed accessory pathway (76 +/- 15 ms, P<0.0001) and control patients (77 +/- 15 ms, P=0.0007), as was PR intervals (165 +/- 25 versus 149 +/- 20 and 150 +/- 21 ms, P<0.0001, respectively) even after excluding those with atrioventricular block. Significant differences in PR and atrial-His intervals were not observed between concealed accessory pathway and control patients. More preexcitation patients had ventriculoatrial dissociation than had patients in the other groups. The results indicate that atrioventricular block is not uncommon in preexcitation patients and a relatively long atrioventricular conduction time is an electrophysiological prerequisite for the manifestation of preexcitation in the Wolff-Parkinson-White syndrome.

Localization of the initial fibrillatory cycle in patients with paroxysmal atrial fibrillation

BACKGROUND

Recent reports suggest the presence of conduction delay in the posterior septal region during sinus rhythm in patients with lone paroxysmal atrial fibrillation (AF).

OBJECTIVE

To explore the location of intra-atrial conduction delay associated with initiation of AF.

DESIGN

In 8 lone AF patients (51 +/- 10 years), 20 AF paroxysms were induced during electrophysiological examination. Bipolar electrograms were acquired from a 10-polar catheter in the coronary sinus (CS), a 4-polar His bundle catheter, and a 20-polar Halo catheter in the right atrium.

RESULTS

Induced AF paroxysms showed earliest registered atrial activity in interatrial septum (IAS) or proximal CS in 17 cases (85%). Conduction delay at the posterior IAS or proximal CS accompanied induction of 18 AF paroxysms (6 patients). Atrial activation sequence at the beginning of the AF paroxysms was stable and reproducible in six repeatedly induced AF episodes (3 patients).

CONCLUSION

In lone AF patients, induction of AF is associated with conduction disturbances in the IAS and proximal CS regions.

Familial occurrence of microscopic colitis: a report on five families

BACKGROUND

The etiology and pathogenesis of microscopic colitis is unknown. Whether genetic predisposition is of importance, as in many other gastrointestinal diseases, is unknown. Familial occurrence of collagenous colitis has earlier been reported only in two families.

METHODS

Familial occurrence of microscopic colitis was searched for in a Swedish national microscopic colitis register.

RESULTS

Familial occurrence of microscopic colitis was identified in five families. In all families a sister-sister relationship was found. Two sisters with collagenous colitis had been living apart in different Nordic countries for many years before developing the disease. In one pair, the smoking sister had collagenous colitis and the never smoking sister had lymphocytic colitis.

CONCLUSIONS

Considering the relative rarity of microscopic colitis, these findings indicate that a genetic predisposition may be of importance.

Further evidence of localized posterior interatrial conduction delay in lone paroxysmal atrial fibrillation

AIMS

Prolongation of interatrial conduction time has been reported in patients with paroxysmal atrial fibrillation (PAF). The study objective was to localize the region of the conduction delay in patients with lone PAF.

METHODS AND RESULTS

Twenty-one patients with lone PAF and 23 patients with AV nodal re-entrant tachycardia ablation without history of PAF (control group) were recruited. Endocardial recordings were made during sinus rhythm and programmed atrial stimulation. The authors measured the interatrial conduction time, the 'right-sided' conduction time between the high lateral right atrium and the proximal coronary sinus (RA-CSp), and the 'left-sided' conduction time between the proximal and the distal coronary sinus (CSp-LA). During sinus rhythm, the interatrial conduction time was longer in the PAF group (103 +/- 19 vs 86 +/- 12 ms, P<0.01) due to delay of right-sided conduction (RA-CSp was 74 +/- 20 vs 56 +/- 10 ms, P<0.01). During programmed stimulation at the distal coronary sinus, the maximal RA-CSp time was also longer in the PAF group (110 +/- 47 vs 69 +/- 16 ms, P<0.05). No differences in CSp-LA time were observed.

CONCLUSION

This study supports the role of posterior septal right atrial conduction disturbances in the genesis of lone PAF.

Activation of neutral sphingomyelinase participates in ethanol-induced apoptosis in Hep G2 cells

The mechanism underlying ethanol-induced apoptosis in liver cells is not clear. Sphingomyelin (SM) metabolism is a novel signal transduction pathway that has an impact on apoptosis in many cell types. We investigated whether the SM pathway is involved in ethanol-induced apoptosis in the liver. Hep G2 cells were treated with ethanol followed by assaying apoptosis, sphingomyelinase (SMase) activity, caspase-3 activity, and the changes of SM content in the cells. We found that ethanol dose-dependently increased apoptosis and the effect was accompanied by increases of caspase-3 activity and neutral SMase activity. At concentrations of 80 and 160 mM, ethanol significantly increased caspase-3 activity by 120% and neutral SMase activity by 24%. The activity of acid SMase was only slightly increased without statistical significance. C(2)-ceramide, the exogenous SM metabolite, mimicked the effects of ethanol on apoptosis and caspase-3 activation. When the SM content was determined 24 h after treatment with ethanol, its level was 15% lower than that of controls. The results indicate that metabolism of SM triggered by neutral SMase participates in ethanol-induced apoptosis in Hep G2 cells and activation of caspase-3 is involved in the apoptotic pathway.

Recording monophasic action potentials using a platinum-electrode ablation catheter

AIMS

The monophasic action potential (MAP) is conventionally recorded using Ag-AgCl electrodes which are not suitable for delivering radiofrequency currents. To be able to use the sharp MAP upstroke for identifying the local activation, as a step towards the development of a MAP-guided catheter ablation technique, the possibility of recording MAP via platinum electrodes of an ordinary ablation catheter was explored.

METHODS AND RESULTS

One hundred and forty-two MAP recordings from the endocardium were obtained via an ablation catheter in 40 patients undergoing electrophysiological study/catheter ablation. During sinus rhythm and pacing, 90% of the ventricular and 100% of the atrial MAPs had stable baselines. The amplitudes were 13 +/- 4.2 mV for ventricular and 2.4 +/- 0.8 mV for atrial MAPs. During mapping and ablation, MAPs and uni- and bipolar electrograms were recorded simultaneously using the same tip electrode in eight patients. The MAPs provided more distinct local activation than the electrograms. During 17 MAP recordings, additional MAPs were recorded simultaneously using an Ag-AgCl electrode catheter in the immediate vicinity of the ablation catheter. The MAPs taken with the ablation catheter had characteristics consistent with those taken with the Ag-AgCl catheter.

CONCLUSIONS

(1) Platinum electrodes can be used for timely recording of MAPs in patients. (2) It is feasible to record MAPs and deliver radiofrequency currents via the same platinum-tip electrode. These findings suggest that MAP-guided catheter ablation is technically possible.

[Atrial fibrillation--new knowledge yields new therapeutic possibilities]

Atrial fibrillation (AF) is the most common cardiac arrhythmia prompting treatment. Advances in our knowledge of the pathophysiology of AF provide the basis for new and improved treatment modalities. Thus, focal excitation and localised impulse conduction defects are possible trigger factors which can be counteracted by focal ablation and pacing synchronisation, respectively. Perpetuation of AF, caused by continuous multisite re-entry, is promoted by successive shortening of repolarisation. Internal defibrillation and anatomical limitation of re-entry are treatments that counteract perpetuation of the arrhythmia. Current knowledge of AF and the application of new treatments are discussed by the Lund AF research group.

Familial adenomatous polyposis is associated with a marked decrease in alkaline sphingomyelinase activity: a key factor to the unrestrained cell proliferation?

The hydrolysis of sphingomyelin generates key molecules regulating cell growth and inducing apoptosis. Data from animal cancer models support an inhibitory role for this pathway in the malignant transformation of the colonic mucosa. In the intestinal tract, a sphingomyelinase with an optimum alkaline pH has been identified. We recently found that the activity of alkaline sphingomyelinase is significantly decreased in colorectal adenocarcinomas, indicating a potential anticarcinogenic role of this enzyme. To further examine whether the reduction of sphingomyelinase is present already in the premalignant state of neoplastic transformation, we measured sphingomyelinase activities in patients with familial adenomatous polyposis (FAP) and in sporadic colorectal tubulovillous adenomas. Tissue samples were taken from adenomas and surrounding macroscopically normal mucosa from 11 FAP patients operated with ileorectal anastomosis, from three FAP patients with intact colon, from 13 patients with sporadic colorectal adenomas and from 12 controls. Activities of acid, neutral and alkaline sphingomyelinase were measured together with alkaline phosphatase. In FAP adenoma tissue, alkaline sphingomyelinase activity was reduced by 90% compared to controls (P < 0.0001), acid sphingomyelinase by 66% (P < 0.01) and neutral sphingomyelinase by 54% (P < 0.05). Similar reductions were found in the surrounding mucosa. In sporadic adenoma tissue, only alkaline sphingomyelinase was reduced significantly, by 57% (P < 0.05). Alkaline phosphatase was not changed in FAP adenomas, but decreased in the sporadic adenomas. We conclude that the markedly reduced levels of alkaline sphingomyelinase activities in FAP adenomas and in the surrounding mucosa may be a pathogenic factor that can lead to unrestrained cell proliferation and neoplastic transformation.

Alkaline sphingomyelinase activity is decreased in human colorectal carcinoma

BACKGROUND

The metabolism of sphingomyelin generates important signals regulating cell proliferation and apoptosis. Previous studies found that the administration of colon carcinoma carcinogen was associated with an accumulation of membrane sphingomyelin, and that dietary sphingomyelin inhibited promotion of experimental colon carcinoma in mice, indicating that the abnormal metabolism of sphingomyelin is linked to colon carcinoma development. However, the changes in sphingomyelinase (SMase) activity in colon carcinoma have not been directly studied. The authors identified, specifically in the intestine, a distinctive alkaline SMase that differs from the known acidic and neutral SMases. The functions and clinical implications of the enzyme are unknown. This study examined the changes in all three SMase activities in human colorectal carcinoma.

METHODS

Tissue samples were taken from colorectal carcinoma and normal mucosa from 18 patients. After homogenization, the activities of acidic, neutral, and alkaline SMase, as well as ceramidase and alkaline phosphatase, were determined. The enzyme activities in cancer tissue were compared with normal tissue from the same patients.

RESULTS

In the normal tissue, there is an activity gradient from the ascending colon to the rectum for neutral and alkaline SMases but not for acidic SMase. In colorectal carcinoma, alkaline SMase activity was preferentially decreased by 75%, whereas acidic and neutral SMase activity decreased by 30% and 50%, respectively. No changes could be found for either ceramidase or alkaline phosphatase activity.

CONCLUSIONS

Alkaline SMase activity preferentially decreases in human colorectal carcinoma, suggesting a regulatory role of the enzyme in colon mucosa cell proliferation.