Calcium Dyshomeostasis Drives Pathophysiology and Neuronal Demise in Age-Related Neurodegenerative Diseases

This review postulates that age-related neurodegeneration entails inappropriate activation of intrinsic pathways to enable brain plasticity through deregulated calcium (Ca2+) signalling. Ca2+ in the cytosol comprises a versatile signal controlling neuronal cell physiology to accommodate adaptive structural and functional changes of neuronal networks (neuronal plasticity) and, as such, is essential for brain function. Although disease risk factors selectively affect different neuronal cell types across age-related neurodegenerative diseases (NDDs), these appear to have in common the ability to impair the specificity of the Ca2+ signal. As a result, non-specific Ca2+ signalling facilitates the development of intraneuronal pathophysiology shared by age-related NDDs, including mitochondrial dysfunction, elevated reactive oxygen species (ROS) levels, impaired proteostasis, and decreased axonal transport, leading to even more Ca2+ dyshomeostasis. These core pathophysiological processes and elevated cytosolic Ca2+ levels comprise a self-enforcing feedforward cycle inevitably spiralling toward high levels of cytosolic Ca2+. The resultant elevated cytosolic Ca2+ levels ultimately gear otherwise physiological effector pathways underlying plasticity toward neuronal demise. Ageing impacts mitochondrial function indiscriminately of the neuronal cell type and, therefore, contributes to the feedforward cycle of pathophysiology development seen in all age-related NDDs. From this perspective, therapeutic interventions to safely restore Ca2+ homeostasis would mitigate the excessive activation of neuronal destruction pathways and, therefore, are expected to have promising neuroprotective potential.

Cytosolic calcium: Judge, jury and executioner of neurodegeneration in Alzheimer's disease and beyond

This review discusses the driving principles that may underlie neurodegeneration in dementia, represented most dominantly by Alzheimer's disease (AD). While a myriad of different disease risk factors contribute to AD, these ultimately converge to a common disease outcome. Based on decades of research, a picture emerges where upstream risk factors combine in a feedforward pathophysiological cycle, culminating in a rise of cytosolic calcium concentration ([Ca2+ ]c ) that triggers neurodegeneration. In this framework, positive AD risk factors entail conditions, characteristics, or lifestyles that initiate or accelerate self-reinforcing cycles of pathophysiology, whereas negative risk factors or therapeutic interventions, particularly those mitigating elevated [Ca2+ ]c , oppose these effects and therefore have neuroprotective potential.

iPSC-derived cortical neurons to study sporadic Alzheimer disease: A transcriptome comparison with post-mortem brain samples

Alzheimer's disease (AD) is the most common cause of dementia, characterized by the progressive impairment of cognition and memory loss. Sporadic AD (sAD) represents approximately 95 % of the AD cases and is induced by a complex interplay between genetic and environmental factors called "Alzheimerogens". Heavy metals (e.g. copper) and pesticides (e.g. fipronil) can affect many AD-related processes, including neuroinflammation (considered as AD-inducing factor). Research would benefit from in vitro models to investigate effects of Alzheimerogens. We compared transcriptomics changes in sAD induced pluripotent stem cell (iPSC) derived cortical neurons to differentially expressed genes (DEGs) identified in post-mortem AD brain tissue. These analyses showed that many AD-related processes could be identified in the sAD iPSC-derived neurons, and furthermore, could even identify more DEGs functioning in these processes than post-mortem AD-brain tissue. Thereafter, we exposed the iPSCs to AD-inducing factors (copper(II)chloride, fipronil sulfone and an inflammatory cytokine cocktail). Cytokine exposure induced expression of immune related genes while copper-exposure affected genes involved in lipid and cholesterol metabolism, which are known AD-related processes. Fipronil-exposure did not result in significant transcriptomic changes, although prolonged exposures or higher doses may be necessary. Overall, we show that iPSC-derived cortical neurons can be beneficial in vitro models to identify Alzheimerogens and AD-related molecular mechanisms.

Modifying Rap1-signalling by targeting Pde6δ is neuroprotective in models of Alzheimer's disease

Background

Neuronal Ca²⁺ dyshomeostasis and hyperactivity play a central role in Alzheimer’s disease pathology and progression. Amyloid-beta together with non-genetic risk-factors of Alzheimer’s disease contributes to increased Ca²⁺ influx and aberrant neuronal activity, which accelerates neurodegeneration in a feed-forward fashion. As such, identifying new targets and drugs to modulate excessive Ca²⁺ signalling and neuronal hyperactivity, without overly suppressing them, has promising therapeutic potential.

Methods

Here we show, using biochemical, electrophysiological, imaging, and behavioural tools, that pharmacological modulation of Rap1 signalling by inhibiting its interaction with Pde6δ normalises disease associated Ca²⁺ aberrations and neuronal activity, conferring neuroprotection in models of Alzheimer’s disease.

Results

The newly identified inhibitors of the Rap1-Pde6δ interaction counteract AD phenotypes, by reconfiguring Rap1 signalling underlying synaptic efficacy, Ca²⁺ influx, and neuronal repolarisation, without adverse effects in-cellulo or in-vivo. Thus, modulation of Rap1 by Pde6δ accommodates key mechanisms underlying neuronal activity, and therefore represents a promising new drug target for early or late intervention in neurodegenerative disorders.

Conclusion

Targeting the Pde6δ-Rap1 interaction has promising therapeutic potential for disorders characterised by neuronal hyperactivity, such as Alzheimer’s disease.

Electronic supplementary material

The online version of this article (10.1186/s13024-018-0283-3) contains supplementary material, which is available to authorized users.

A Prospective Comparison of 99mTc-Labeled Polyclonal Human Immunoglobulin and 111In Granulocytes for Localization of Inflammatory Bowel Disease

There is a need for an easily prepared radiopharmaceutical agent for the detection of inflammation and infection. In a group of 14 patients with inflammatory bowel disease (IBD), the detection of actively involved intestinal segments by nonspecific human polyclonal immunoglobulin (IgG) labeled with 99mTc was compared with that of 111In granulocytes. To determine the specificity of 99mTc-IgG scintigraphy, 8 control patients without clinical indications of intestinal inflammation were examined. 99mTc-IgG was found in the left colon in 8 and in the right colon in 7 of the 8 controls 4 hours after the injection. At that time of scintigraphy only 4 IBD patients exhibited a more intense accumulation at the site of the intestinal segments with active disease. In contrast, in a randomized comparison with 111In granulocytes scintigraphy was positive in 11 patients with the latter technique. Moreover, fewer diseased segments were seen in the 4 patients with positive 99mTc-IgG scintigraphy (6 versus 12 with 111In granulocytes). In view of the low sensitivity and specificity, it is concluded that 99mTc-IgG is not suitable for the scintigraphic staging of IBD patients.

Derailed intraneuronal signalling drives pathogenesis in sporadic and familial Alzheimer's disease

Although a wide variety of genetic and nongenetic Alzheimer's disease (AD) risk factors have been identified, their role in onset and/or progression of neuronal degeneration remains elusive. Systematic analysis of AD risk factors revealed that perturbations of intraneuronal signalling pathways comprise a common mechanistic denominator in both familial and sporadic AD and that such alterations lead to increases in Aβ oligomers (Aβo) formation and phosphorylation of TAU. Conversely, Aβo and TAU impact intracellular signalling directly. This feature entails binding of Aβo to membrane receptors, whereas TAU functionally interacts with downstream transducers. Accordingly, we postulate a positive feedback mechanism in which AD risk factors or genes trigger perturbations of intraneuronal signalling leading to enhanced Aβo formation and TAU phosphorylation which in turn further derange signalling. Ultimately intraneuronal signalling becomes deregulated to the extent that neuronal function and survival cannot be sustained, whereas the resulting elevated levels of amyloidogenic Aβo and phosphorylated TAU species self-polymerizes into the AD plaques and tangles, respectively.

Substituted 2-aminothiazoles are exceptional inhibitors of neuronal degeneration in tau-driven models of Alzheimer's disease

A novel series of 2-aminothiazoles with strong protection in an Alzheimer's disease (AD) model comprising tau-induced neuronal toxicity is disclosed. These derivatives can be synthesized in one-pot and a small SAR of the substitution within these series afforded several compounds that counteracted tau-induced cell toxicity at nanomolar concentrations. These congeners therefore have strong potential as possible treatment for Alzheimer's disease and other related tauopathies.

Pathological Hallmarks, Clinical Parallels, and Value for Drug Testing in Alzheimer's Disease of the APP[V717I] London Transgenic Mouse Model

The APP[V717I] London (APP-Ld) mouse model recapitulates important pathological and clinical hallmarks of Alzheimer's disease (AD) and is therefore a valuable paradigm for evaluating therapeutic candidates. Historically, both the parenchymal and vascular amyloid deposits, and more recently, truncated and pyroglutamate-modified Abeta_3(pE)-42 species, are perceived as important hallmarks of AD-pathology. Late stage symptoms are preceded by robust deficits in orientation and memory that correlate in time with Abeta oligomerization and GSK3β-mediated phosphorylation of endogenous murine Tau, all markers that have gained considerable interest during the last decade. Clinical parallels with AD patients and the value of the APP-Ld transgenic mouse model for preclinical in vivo testing of candidate drugs are discussed.

Evaluation of the Vitotox and RadarScreen assays for the rapid assessment of genotoxicity in the early research phase of drug development

The Vitotox and RadarScreen assays were evaluated as early screens for mutagenicity and clastogenicity, respectively. The Vitotox assay is a bacterial reporter assay in Salmonella typhimurium based on the SOS-response, and it contains a luciferase gene under control of the recN promoter. The RadarScreen assay is a RAD54 promoter-linked beta-galactosidase reporter assay in yeast. The expression of this beta-galactosidase can easily be quantified by use of the substrate d-luciferin-o-beta-galactopyranoside, which is converted into galactose and luciferin that can be measured luminometrically. Recently, an ECVAM workgroup defined a list of 20 genotoxic and 42 non-genotoxic compounds [D. Kirkland, P. Kasper, L. Muller, R. Corvi, G. Speit, Recommended lists of genotoxic and non-genotoxic chemicals for assessment of the performance of new or improved genotoxicity tests: a follow-up to an ECVAM workshop, Mutat. Res. 653 (2008) 99-108.] that can be used for the validation and/or optimization of in vitro genotoxicity assays. In the present study, this compound set was used for the validation of the assays. Moreover, an additional set of 192 compounds was used to broaden this validation study. The compounds of this additional set can be classified as non-genotoxins and genotoxins and consists of both in-house and reference compounds. In case of the ECVAM compound list, the results from the Vitotox and RadarScreen assays were compared to the genotoxic/non-genotoxic classification of the compounds in this list. In case of the additionally tested compounds, the results of the Vitotox and RadarScreen assays were compared, respectively, with bacterial mutagenicity (Ames) results or in vitro clastogenicity data obtained in-house or from the literature. The validation with respect to the ECVAM compound list resulted in a sensitivity for both the Vitotox and RadarScreen assay of 70% (14/20). If both assays were combined the sensitivity increased to 85% (17/20). Both tests also gave a low number of false positive results. The specificity of the Vitotox and RadarScreen assays was 93% (39/42) and 83% (35/42), respectively. This resulted in a predictivity of the Vitotox and RadarScreen assay of 85% (53/62) and 79% (49/62), respectively. In case both tests were combined the specificity and the predictivity of the Vitotox and RadarScreen assay turned out to be 81% (34/42) and 82% (51/62), respectively. The results from the additional list of 192 compounds confirmed the results found with the ECVAM compound list. The results from the Vitotox assay showed a high correlation with Ames test of 91% (132/145). Subsequently, the RadarScreen assay had a correlation with in vitro clastogenicity of 76% (93/123). The specificity of the Vitotox assay was 94% (90/96) for Ames test results and that of the RadarScreen assay was 74% (34/46) for clastogenicity. Moreover, the sensitivities of the Vitotox and RadarScreen assays were 86% (42/49) and 77% (59/77), respectively. Implementation of the Vitotox and RadarScreen assays in the early research phase of drug development can lead to fast de-selection for genotoxicity. It is expected that this application will reduce the number of compounds that have a positive score in the regulatory Ames and clastogenicity tests. Moreover, problems with a complete compound class can be foreseen at an early time point in the research phase, which gives more time for issue resolution than late detection of these problems with the regulatory tests.

Targeting disease, not disease targets: Innovative approaches in tackling neurodegenerative disorders

Preclinical drug investigation entails identifying and optimizing drug candidates to yield effective therapeutics with an acceptable level of adverse side effects. Inevitably, this investigation phase is bound to using model systems that mimic crucial aspects of disease biology in order to assess drug efficacy. The quality or predictability of these disease models is therefore of utmost importance to the development of successful drugs. Models should also be cost-effective and, from a biological point of view, sufficiently simple to enable molecules that act specifically (ie, that modulate a single, pre-defined target) to be identified easily and to allow for HTS. To meet these demands, typical drug discovery approaches rely heavily on biochemical assays in which the activity of a pre-defined target is reconstituted artificially. However, such a rational reductionist approach may compromise the predictability of a model because targets are assessed in an artificial environment that is deprived of any relevant biological context. Moreover, given the pre-established limits on target space and mode of action in a model, efficient and innovative drug discovery programs may be hampered. This feature article considers alternative or complementary approaches that advocate the introduction of biological context early in the drug discovery process. A case study of how NV reMYND has implemented 'biology-driven' drug discovery is presented.

Clinical impact of MMP and TIMP gene polymorphisms in gastric cancer

Gastric cancers express enhanced levels of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). Single-nucleotide polymorphisms (SNPs) in MMP and TIMP genes may be associated with disease susceptibility and might also affect their antigen expression. We studied the genotype distribution and allele frequencies of SNPs of MMP-2, -7, -8 and -9 and TIMP-1 and -2 in gastric cancer patients in relation to tumour progression, patient survival and tissue antigen expression. The genotype distribution and allele frequencies were similar in gastric cancer patients and controls, except for MMP-7_−181A>G. In addition, the genotype distribution of MMP-7_−181A>G was associated with Helicobacter pylori status (χ² 7.8, P=0.005) and tumour-related survival of the patients. Single-nucleotide polymorphism TIMP-2_303C>T correlated significantly with the WHO classification (χ² 5.9, P=0.03) and also strongly with tumour-related survival (log rank 11.74, P=0.0006). Single-nucleotide polymorphisms of MMP-2, -8, -9 and TIMP-1 were not associated with tumour-related survival. Only the gene promoter MMP-2_−1306C>T polymorphism correlated significantly with the protein level within the tumours. First-order dendrogram cluster analysis combined with Cox analysis identified the MMP-7_−181A>G and TIMP-2_303C>T polymorphism combination to have a major impact on patients survival outcome. We conclude that MMP-related SNPs, especially MMP-7_−181A>G and TIMP-2_303C>T, may be helpful in identifying gastric cancer patients with a poor clinical outcome.

What is the appropriate screening protocol in Lynch syndrome?

INTRODUCTION

Lynch syndrome families have a substantial risk of developing colorectal cancer (CRC). The recommended surveillance protocol includes colonoscopy every 2 years from age 20-25 years. It is yet unknown whether annual screening of patients aged 40-60 years is more effective than bi-annual screening, whether patients who had an adenoma removed should be re-examined after a year and whether surveillance of second-degree relatives is indicated. The aim of this study was to address these issues.

METHODS

All carriers of a mismatch repair gene mutation who participated in the surveillance program were selected from the Dutch Lynch syndrome registry. The results of colonoscopy were prospectively collected.

RESULTS

A total of 666 mutation carriers were identified in 110 families. Fourty-one CRCs were detected during endoscopic follow-up, of which 34 (83%) were diagnosed between age 40 and 60 years. In five of 34 patients, CRC was diagnosed within 1 year after colonoscopy, eight cancers were diagnosed between 1 and 2 years and the remaining tumors more than 2 years after colonoscopy. All eight CRCs detected between 1 and 2 years were at local stage. At least one adenoma was diagnosed at 141 examinations. The risk of developing CRC during follow-up in carriers with an adenoma was similar as in carriers without an adenoma at the previous colonoscopy. 280 parent-child couples with at least one Lynch syndrome-related carcinoma were identified in 110 families. In only 19 (6.8%) of these couples, CRC developed earlier in the child than an Lynch syndrome-associated cancer in the parent.

CONCLUSION

The current surveillance protocol, i.e., bi-annual colonoscopy in first-degree relatives independent of age and endoscopic findings, appears to be appropriate.

Matrix metalloproteinase-2 is a consistent prognostic factor in gastric cancer

In a pioneer study, we showed 10 years ago that enhanced tissue levels of the matrix metalloproteinases (MMPs) MMP-2 and MMP-9 in gastric cancers, as determined by zymography, were related with worse overall survival of the patients. To corroborate these observations, we now assessed MMP-2 and MMP-9 with new techniques in an expanded group of gastric cancer patients (n=81) and included for comparison MMP-7, MMP-8 and the tissue inhibitors of MMPs, TIMP-1 and -2. All MMPs and TIMP-1 were significantly increased in tumour tissue compared to normal gastric mucosa. Matrix metalloproteinase-7, -8 and -9, and the TIMPs showed some correlations with the clinicopathologic parameters TNM, WHO and Laurén classification, but their levels were not related with survival. Regardless of the determination method used, that is, enzyme-linked immunosorbent assay or bioactivity assay, an enhanced tumour MMP-2 level did not show a significant correlation with any of the clinicopathological parameters, but was confirmed to be an independent prognostic factor in gastric cancer.

Ileum resection is the most predictive factor for osteoporosis in patients with Crohn's disease

INTRODUCTION

Crohn's disease is associated with a host of factors potentially increasing the risk for osteoporosis and fractures. The aim of our study was to identify the most predictive factors for skeletal pathology in this patients.

METHODS

Using a cross-sectional study design, 146 randomly selected patients with Crohn's disease of variable disease activity who were given standard therapy to control disease activity, including glucocorticoids, and who attended the outpatient clinic of the Gastroenterology Unit on regular follow-up visits were studied. Bone mineral density (BMD) measurements and lateral X-rays of the spine were performed, and biochemical parameters of bone turnover, gonadal hormones and C-reactive protein (CRP) as markers of disease activity were measured in all patients.

RESULTS

There were 61 men and 85 women, with a mean age of 43 years and mean disease duration of 20 years. The majority of patients (86%) had been treated with glucocorticoids at some stage during their illness at a median dose of 7.5 mg/day, 43% were currently using these agents and 66% had undergone an intestinal resection. Twenty-one percent of patients had below-normal 25-hydroxy vitamin D levels. Osteoporosis was documented in 26% of patients, predominantly at the femoral neck, but also at the lumbar spine or at both sites; osteopenia was documented in 45% of patients. Prevalence of vertebral and non-vertebral fractures was, respectively, 6% and 12%. Ileum resection was the most predictive factor for osteoporosis: RR 3.84 (CI 1.24-9.77, p=0.018), followed by age: RR 1.05 (CI 1.02-1.08, p<0.001) and current or past glucocorticoid use: RR 1.94 (CI 0.92-4.10, p=0.08).

CONCLUSION

Our data suggest that in patients with Crohn's disease, the risk of osteoporosis is best predicted by a history of ileum resection.

A yeast-based model of alpha-synucleinopathy identifies compounds with therapeutic potential

We have developed a yeast-based model recapitulating neurotoxicity of alpha-synuclein fibrilization. This model recognized metal ions, known risk factors of alpha-synucleinopathy, as stimulators of alpha-synuclein aggregation and cytotoxicity. Elimination of Yca1 caspase activity augmented both cytotoxicity and inclusion body formation, suggesting the involvement of apoptotic pathway components in toxic alpha-synuclein amyloidogenesis. Deletion of hydrophobic amino acids at positions 66-74 in alpha-synuclein reduced its cytotoxicity but, remarkably, did not lower the levels of insoluble alpha-synuclein, indicating that noxious alpha-synuclein species are different from insoluble aggregates. A compound screen aimed at finding molecules with therapeutic potential identified flavonoids with strong activity to restrain alpha-synuclein toxicity. Subsequent structure-activity analysis elucidated that these acted by virtue of anti-oxidant and metal-chelating activities. In conclusion, this yeast-cell model as presented allows not only fundamental studies related to mechanisms of alpha-synuclein-instigated cellular degeneration, but is also a valid high-throughput identification tool for novel neuroprotective agents.

Characterization of alpha-synuclein aggregation and synergistic toxicity with protein tau in yeast

A yeast model was generated to study the mechanisms and phenotypical repercussions of expression of alpha-synuclein as well as the coexpression of protein tau. The data show that aggregation of alpha-synuclein is a nucleation-elongation process initiated at the plasma membrane. Aggregation is consistently enhanced by dimethyl sulfoxide, which is known to increase the level of phospholipids and membranes in yeast cells. Aggregation of alpha-synuclein was also triggered by treatment of the yeast cells with ferrous ions, which are known to increase oxidative stress. In addition, data are presented in support of the hypothesis that degradation of alpha-synuclein occurs via autophagy and proteasomes and that aggregation of alpha-synuclein disturbs endocytosis. Reminiscent of observations in double-transgenic mice, coexpression of alpha-synuclein and protein tau in yeast cells is synergistically toxic, as exemplified by inhibition of proliferation. Taken together, the data show that these yeast models recapitulate major aspects of alpha-synuclein aggregation and cytotoxicity, and offer great potential for defining the underlying mechanisms of toxicity and synergistic actions of alpha-synuclein and protein tau.

Endoscopic treatment of Barrett's oesophagus

Barrett's oesophagus develops as a consequence of severe gastro-oesophageal reflux. The importance of Barrett's oesophagus lies in the small risk of developing high-grade dysplasia and subsequent adenocarcinoma. Because of poor treatment results in patients with advanced adenocarcinoma, surveillance of patients with Barrett's oesophagus for the development of dysplasia, although not uncontroversial, is widely practised in the gastroenterological community. The aim of surveillance is to detect adenocarcinoma in an early stadium where surgical cure is possible. In recent years several endoscopic treatments for both high-grade dysplasia and intramucosal adenocarcinoma have been developed. In this review some basic aspects of Barrett's oesophagus are discussed together with endoscopic treatments such as endoscopic mucosal resection, local thermal treatments and photodynamic therapy. Although surgical resection is probably the treatment of choice in fit patients, local endoscopic treatments should be considered in patients with high-grade dysplasia or intramucosal carcinoma who are unfit or unwilling to have surgery.

PKA and Sch9 control a molecular switch important for the proper adaptation to nutrient availability

In the yeast Saccharomyces cerevisiae, PKA and Sch9 exert similar physiological roles in response to nutrient availability. However, their functional redundancy complicates to distinguish properly the target genes for both kinases. In this article, we analysed different phenotypic read-outs. The data unequivocally showed that both kinases act through separate signalling cascades. In addition, genome-wide expression analysis under conditions and with strains in which either PKA and/or Sch9 signalling was specifically affected, demonstrated that both kinases synergistically or oppositely regulate given gene targets. Unlike PKA, which negatively regulates stress-responsive element (STRE)- and post-diauxic shift (PDS)-driven gene expression, Sch9 appears to exert additional positive control on the Rim15-effector Gis1 to regulate PDS-driven gene expression. The data presented are consistent with a cyclic AMP (cAMP)-gating phenomenon recognized in higher eukaryotes consisting of a main gatekeeper, the protein kinase PKA, switching on or off the activities and signals transmitted through primary pathways such as, in case of yeast, the Sch9-controlled signalling route. This mechanism allows fine-tuning various nutritional responses in yeast cells, allowing them to adapt metabolism and growth appropriately.

Decision analysis in the surgical treatment of colorectal cancer due to a mismatch repair gene defect

BACKGROUND

In view of the high risk of developing a new primary colorectal carcinoma (CRC), subtotal colectomy rather than segmental resection or hemicolectomy is the preferred treatment in hereditary non-polyposis colorectal cancer (HNPCC) patients. Subtotal colectomy however implies a substantial decrease in quality of life. To date, colonoscopic surveillance has been shown to reduce CRC occurrence.

AIMS

To compare the potential health effects in terms of life expectancy (LE) for patients undergoing subtotal colectomy or hemicolectomy for CRC.

METHODS

A decision analysis (Markov) model was created. Information on the 10 year risk of CRC after subtotal colectomy (4%) and hemicolectomy (16%) and stages of CRCs detected within a two year surveillance interval (32% Dukes' A, 54% Dukes' B, and 14% Dukes' C) were derived from two cohort studies. Five year survival rates used for the different Dukes stages (A, B, and C) were 98%, 80%, and 60%, respectively. Remaining LE values were calculated for hypothetical cohorts with an age at CRC diagnosis of 27, 47, and 67 years, respectively. Remaining LE values were also calculated for patients with CRC of Dukes' stage A.

RESULTS

The overall LE gain of subtotal colectomy compared with hemicolectomy at ages 27, 47, and 67 was 2.3, 1, and 0.3 years, respectively. Specifically for Dukes' stage A, this would be 3.4, 1.5, and 0.4 years.

CONCLUSIONS

Unless surveillance results improve, subtotal colectomy still seems the preferred treatment for CRC in HNPCC in view of the difference in LE. For older patients, hemicolectomy may be an option as there is no appreciable difference in LE.

Feedback inhibition on cell wall integrity signaling by Zds1 involves Gsk3 phosphorylation of a cAMP-dependent protein kinase regulatory subunit

We report here that budding yeast cAMP-dependent protein kinase (cAPK) is controlled by heat stress. A rise in temperature from 30 to 37 degrees C was found to result in both a higher expression and an increased cytoplasmic localization of its regulatory subunit Bcy1. Both of these effects required phosphorylation of serines located in its localization domain. Surprisingly, classic cAPK-controlled processes were found to be independent of Bcy1 phosphorylation, indicating that these modifications do not affect cAPK activity as such. Alternatively, phosphorylation may recruit cAPK to, and thereby control, a specific subset of (perhaps novel) cAPK targets that are presumably localized extranuclearly. Zds1 and Zds2 may play a role in this process, since these were found required to retain hyperphosphorylated Bcy1 in the cytoplasm at 37 degrees C. Mck1, a homologue of mammalian glycogen synthase kinase 3 and a downstream component of the heat-activated Pkc1-Slt2/Mpk1 cell wall integrity pathway, is partly responsible for hyperphosphorylations of Bcy1. Remarkably, Zds1 appears to act as a negative regulator of cell wall integrity signaling, and this activity is dependent in part on the phosphorylation status of Bcy1. Thus, Mck1 phosphorylation of Bcy1 and Zds1 may constitute an unprecedented negative feedback control on the cell wall integrity-signaling pathway.

Worldwide survey among polyposis registries of surgical management of severe duodenal adenomatosis in familial adenomatous polyposis

BACKGROUND

The lifetime risk of developing duodenal cancer in familial adenomatous polyposis (FAP) is about 5 per cent. When and to what extent surgical intervention should be undertaken to prevent death from invasive carcinoma is controversial. The aim of this study was to determine the effectiveness of various surgical treatments for cancer and severe duodenal adenomatosis.

METHODS

A questionnaire was mailed to the members of the Leeds Castle Polyposis Group to obtain data on patients with FAP, treated for duodenal cancer or severe duodenal adenomatosis after 1990.

RESULTS

Sixty-nine patients were included. The indication for surgery was invasive cancer in 13 patients, of whom six died from metastatic disease. Fifty-six patients were initially treated for severe duodenal adenomatosis, five (9 per cent) of whom died from metastatic disease (P = 0.002). In surviving patients, adenomas recurred after ampullectomy (six of eight, at mean follow-up of 11 months), after duodenotomy with polypectomy (17 of 21, at mean 29 months) and after pancreatoduodenectomy (six of 25, at mean 47 months). None of six patients who underwent a pancreas-sparing duodenectomy had recurrence of adenoma (mean follow-up 11 months).

CONCLUSION

Surgery for duodenal adenomatosis should take place before endoscopic biopsy reveals invasive cancer. Even after extensive surgical procedures, small bowel adenomas may occur, emphasizing the need for chemoprevention.

[Desmoid tumors in patients with familial adenomatous polyposis]

Desmoid tumours (DT) are slow-growing tumours that consist of proliferations of well-differentiated fibroblasts. Although the typical characteristics of malignant tumours, such as distant metastases, are absent, the tumours are locally aggressive and grow into neighbouring structures. The prevalence of desmoid tumours in patients with FAP is 7-12%. The lifetime risk of developing desmoid tumours is about 20%. In FAP, most tumours are intra-abdominal or located in the abdominal wall. Next to colorectal cancer, desmoid tumours are the most frequent cause of death in FAP. Possible risk factors for the development of desmoid tumours are previous surgical procedures, pregnancy, female sex, a family history of desmoid tumours, and specific mutations in the APC-gene. Both CT scanning and MRI can be used to detect the tumours. An excision biopsy is needed to establish the diagnosis. Medicinal treatment with NSAIDs is the treatment of first choice, followed by hormonal treatment (e.g., tamoxifen) in combination with NSAIDs. Both forms of treatment lead to a response in about 30-50% of the patients. Surgery is the preferred treatment for extra-abdominal tumours or tumours located in the abdominal wall. Surgical treatment of intra-abdominal tumours is only indicated in patients with obstruction of the bowel or ureter. Chemotherapy is indicated in patients with progressive desmoid tumours when non-cytotoxic treatment has failed. Radiotherapy may play a role in the treatment of irresectable extra-abdominal or abdominal wall tumours, or as adjuvant treatment of tumours with positive margins.

Molecular mechanisms controlling the localisation of protein kinase A

cAMP-dependent protein kinases (PKA) are ubiquitous signalling molecules that mediate many extracellular signals in eukaryotes from yeast to men. Directing PKA to its substrates is an important level of control to ensure specificity of cAMP-mediated signal transduction. Unlike in yeast and fungi, in mammalian cells a relatively sophisticated insight has been obtained in the controls of PKA localisation and in fact has set the stage for future research on PKA targeting in unicellular eukaryotes. In this review, we present an integrated overview on molecular mechanisms of PKA regulatory and catalytic subunit localisation in both yeast and multicellular organisms; and we focus in more detail on recent advances of PKA localisation in the unicellular eukaryote Saccharomyces cerevisiae.

Ileoanal pouch function is related to postprandial pouch tone

BACKGROUND

Functional impairments are frequently observed in patients with an ileoanal pouch. Meal ingestion increases pouch tone and motility. Little is known, however, about the influence of meal-stimulated pouch characteristics on pouch function. The aim was to characterize basal and postprandial pouch motor and sensory characteristics in relation to clinical pouch function in patients with an ileoanal pouch.

METHODS

Nineteen patients with an ileoanal pouch, without faecal incontinence but with either a high stool frequency (n = 8) or an adequate stool frequency (n = 11), underwent pressure distension of the pouch, by which pouch compliance and sensitivity characteristics were assessed using an electronic barostat. A set pressure procedure was performed to assess the influence of a meal on pouch tone and motility.

RESULTS

Mean(s.d.) compliance was 10(6) and 11(4) ml/mmHg in the groups with poor and adequate pouch function respectively (P not significant). Mean(s.d.) visual analogue scale scores (0-10 cm) for urge at the highest pressure of 28 mmHg were 2.3(1.0) versus 2.3(2.4) cm respectively (P not significant); those for pain were 0.8(1.0) versus 0.5(0.7) (P not significant). Postprandially mean(s.d.) pouch volume decreased by 70(24) per cent in the group with poor pouch function and 29(25) per cent in the group with adequate pouch function (P < 0.01). The frequency and amplitude of phasic pouch contractions increased significantly postprandially, but no differences in motility characteristics were observed between the two groups.

CONCLUSION

In patients with uniform pouch design and follow-up after pouch construction, pouch compliance and sensitivity were no different between patients with normal and high stool frequency; however, postprandial pouch tone was increased significantly in patients with a high stool frequency.

MSH2 mutation carriers are at higher risk of cancer than MLH1 mutation carriers: a study of hereditary nonpolyposis colorectal cancer families

PURPOSE

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disease characterized by the clustering of colorectal cancer, endometrial cancer, and various other cancers. The disease is caused by mutations in DNA-mismatch-repair (MMR) genes, most frequently in MLH1, MSH2, and MSH6. The aims of the present study were to compare the risk of developing colorectal, endometrial, and other cancers between families with the various MMR-gene mutations.

PATIENTS AND METHODS

Clinical and pathologic data were collected from 138 families with HNPCC. Mutation analyses were performed for all families. Survival analysis was used to calculate the cumulative risk of developing cancer in the various subsets of relatives.

RESULTS

Mutations were identified in 79 families: 34 in MLH1, 40 in MSH2, and five in MSH6. The lifetime risk of developing cancer at any site was significantly higher for MSH2 mutation carriers than for MLH1 mutation carriers (P < .01). The risk of developing colorectal or endometrial cancer was higher in MSH2 mutation carriers than in MLH1 mutation carriers, but the difference was not significant (P = .13 and P = .057, respectively). MSH2 mutation carriers were found to have a significantly higher risk of developing cancer of the urinary tract (P < .05). The risk of developing cancer of the ovaries, stomach, and brain was also higher in the MSH2 mutation carriers than in the MLH1 mutation carriers, but the difference was not statistically significant.

CONCLUSION

Pending large prospective studies, the extension of the current surveillance program in MSH2 mutation carriers with the inclusion of the urinary tract should be considered.

How effective is extensive nonsurgical treatment of patients with clinically active Crohn's disease of the terminal ileum in preventing surgery?

BACKGROUND/AIMS

The purpose of this study is to determine the effectiveness of extensive nonsurgical management of patients with clinically active Crohn's disease of the terminal ileum and to identify parameters that could predict failure of this nonsurgical approach.

METHODS

All consecutive patients hospitalized for the first time because of active Crohn's disease of the terminal ileum between 1985 and 1994 were included. Two groups of patients were defined. Patients who responded favorably to the extensive treatment protocol (group I), and patients in whom an ileocolic resection had been performed (group II). Treatment and patient characteristics were related to outcome.

RESULTS

Twenty-nine (38%) of the 76 patients were treated successfully by nonsurgical management (group I) and did not have surgery until the end of follow-up (mean 8.0 years, range 3-12 years). In total, 47 patients (62%) had ileocolic resection (group II). Logistic regression analysis revealed that a longer time between onset and exacerbation of this disease, the presence of stenosis and extraintestinal manifestations were independent predictors of failure of nonsurgical treatment.

CONCLUSION

Prolonged medical treatment is effective in only one third of the clinically admitted patients. It should be applied with caution particularly in patients exhibiting stenosis, extraintestinal manifestations or a known history of Crohn's disease of more than 5 years.

Chemoprevention of colorectal cancer by non-steroidal anti-inflammatory drugs

AIM

To critically analyse the role of NSAIDs in colorectal cancer.

METHODS

Update of the chemoprotective effect of NSAIDs on colorectal cancer.

RESULTS AND CONCLUSION

Over the past 20 years exciting developments in clinical and basic research have opened up the possibility of NSAID-induced colorectal cancer chemoprevention. In particular, disclosure of the multistep genetic pathway of colorectal carcinogenesis and recognition of the impact of the COX-2 gene on this process have been of utmost importance. These findings have led to the possibility of colorectal cancer prevention by the administration of agents such as NSAIDs. Although it is accepted that these agents are potent inhibitors of colorectal carcinogenesis, their side effects in long-term use are of concern to clinicians dealing with colorectal cancer prevention. Moreover, neither the dose nor the duration of the medication, nor the most ideal compound with respect to protective effects against colorectal cancer, has been defined. Recently, selective COX-2 inhibitors have been developed which may show additional benefit compared to the classical NSAIDs. However, their efficacy and safety profiles need to be established firmly before large-scale use in colorectal cancer prevention can be considered. Based on the exciting developments it is anticipated that a more precise understanding of the molecular details of colorectal carcinogenesis will finally lead to the optimal chemopreventive regimen.

Barium enema and endoscopy for the detection of colorectal neoplasia: sensitivity, specificity, complications and its determinants

AIM

To analyse sensitivity, specificity and complication rate of endoscopy, and barium enema for the detection of colorectal neoplasia.

MATERIALS AND METHODS

A MEDLINE search was performed (1980-2000) directed at the endoscopic and radiologic literature on barium enema. Articles were selected based on the type of study, availability of sensitivity and specificity values in sizeable patient groups, and reports on complications. Sixty articles were included in the analysis.

RESULTS

Endoscopy proved to have superior sensitivity for polyps in patients at high-risk for colorectal neoplasia. The role of endoscopy and radiology in average-risk screening populations is not known. Sensitivity and specificity rates ranged widely, probably due to bias. For the detection of small polyps endoscopy has superior performance, whereas sensitivity is similar for endoscopy and barium enema for the detection of larger (>1 cm) polyps and tumours. Overall, endoscopy is associated with a higher complication rate.

CONCLUSION

Endoscopy is the preferred detection method in high-risk patients. The role of endoscopy and radiology in a screening setting requires evaluation. This review provides the test characteristics of endoscopy and radiology which are relevant for a cost-effectiveness analysis. Double-contrast barium enema may play an important role for screening purposes, owing to its good sensitivity for detecting larger (>1 cm) polyps and its lack of major complications. de Zwart, I. M.et al. (2001). Clinical Radiology56, 401-409.

Comparison of ileoanal pouch and rectal function measured by barostat

The aim of this study was to compare pouch and rectal sensory and motor characteristics and to assess the influence of a meal on pouch tone and motility. Fifteen patients with an ileoanal J-pouch, with adequate pouch function and 12 healthy controls were studied. Visceral compliance was assessed using an electronic barostat by a pressure distension procedure, during which also sensitivity was scored by visual analog scales (VAS). The response to a meal was assessed during set pressure. Pouch and rectal compliance were not significantly different (9.3+/-0.7 vs 10.6+/-1.1 ml/mm Hg). VAS score for urge at 28 mm Hg was reduced in patients: 2.4+/-0.5 cm vs 4.7+/-0.9 cm in controls (P < 0.05). The postprandial decrease in intra-bag volume was more pronounced in patients (44+/-11%) than in controls (9+/-6%, P < 0.01). Postprandial phasic contractions were also more pronounced in patients. In conclusion, compliance is not significantly different between ileoanal pouch and rectum; differences in sensitivity reach significance only at high pressure. Significant differences were especially observed in the postprandial state with an increase in tone and frequency of phasic contractions in pouch patients.

Metallothionein in human gastrointestinal cancer

Metallothionein (MT) is a small thiol-rich metalloprotein with antioxidant properties, involved in tumour pathophysiology and therapy resistance. In order to assess the contribution of MT in gastrointestinal carcinogenesis, this study examined both the MT content by radioimmunoassay and the MT localization by immunohistochemistry in pairs of neoplastic and normal-appearing human gastrointestinal tissues. In addition, the relationship between MT expression and major clinicopathological parameters was assessed. The MT concentration of gastric carcinomas and of colorectal adenomas, carcinomas, and liver metastases was found to be significantly lower than that of corresponding normal-appearing tissue. A relatively high MT content, however, was found to be associated with the villous character of colorectal adenomas and with the Dukes' stage of colorectal carcinomas, indicating a relationship between MT level and malignant potential. Immunohistochemical evaluation showed a fairly good correlation with these quantitative data. MT was found to be expressed at a low level and in a patchy pattern in the gastrointestinal neoplastic and metastatic tissues, whereas in normal-appearing gastrointestinal mucosa MT was uniformly distributed in the cytoplasm and/or nucleus of apical cells. Although in the gastric cancer patients no association was found between the MT concentration and the clinicopathological parameters, the strong MT expression in areas with intestinal metaplasia, known to have neoplastic potential, further points to a relationship between this antioxidant metalloprotein and the malignant character of cells. Gastrointestinal neoplasms are apparently accompanied by a low level and decreased expression of MT, but those with a relatively high level seem to have an increased malignant potential. Further studies will be required to determine the clinical relevance of these observations.

Nucleocytoplasmic distribution of budding yeast protein kinase A regulatory subunit Bcy1 requires Zds1 and is regulated by Yak1-dependent phosphorylation of its targeting domain

In Saccharomyces cerevisiae the subcellular distribution of Bcy1 is carbon source dependent. In glucose-grown cells, Bcy1 is almost exclusively nuclear, while it appears more evenly distributed between nucleus and cytoplasm in carbon source-derepressed cells. Here we show that phosphorylation of its N-terminal domain directs Bcy1 to the cytoplasm. Biochemical fractionation revealed that the cytoplasmic fraction contains mostly phosphorylated Bcy1, whereas unmodified Bcy1 is predominantly present in the nuclear fraction. Site-directed mutagenesis of two clusters (I and II) of serines near the N terminus to alanine resulted in an enhanced nuclear accumulation of Bcy1 in ethanol-grown cells. In contrast, substitutions to Asp led to a dramatic increase of cytoplasmic localization in glucose-grown cells. Bcy1 modification was found to be dependent on Yak1 kinase and, consequently, in ethanol-grown yak1 cells the Bcy1 remained nuclear. A two-hybrid screen aimed to isolate genes encoding proteins that interact with the Bcy1 N-terminal domain identified Zds1. In ethanol-grown zds1 cells, cytoplasmic localization of Bcy1 was largely absent, while overexpression of ZDS1 led to increased cytoplasmic Bcy1 localization. Zds1 does not regulate Bcy1 modification since this was found to be unaffected in zds1 cells. However, in zds1 cells cluster II-mediated, but not cluster I-mediated, cytoplasmic localization of Bcy1 was found to be absent. Altogether, these results suggest that Zds1-mediated cytoplasmic localization of Bcy1 is regulated by carbon source-dependent phosphorylation of cluster II serines, while cluster I acts in a Zds1-independent manner.

Metallothionein in human gastrointestinal cancer

Metallothionein (MT) is a small thiol-rich metalloprotein with antioxidant properties, involved in tumour pathophysiology and therapy resistance. In order to assess the contribution of MT in gastrointestinal carcinogenesis, this study examined both the MT content by radioimmunoassay and the MT localization by immunohistochemistry in pairs of neoplastic and normal-appearing human gastrointestinal tissues. In addition, the relationship between MT expression and major clinicopathological parameters was assessed. The MT concentration of gastric carcinomas and of colorectal adenomas, carcinomas, and liver metastases was found to be significantly lower than that of corresponding normal-appearing tissue. A relatively high MT content, however, was found to be associated with the villous character of colorectal adenomas and with the Dukes' stage of colorectal carcinomas, indicating a relationship between MT level and malignant potential. Immunohistochemical evaluation showed a fairly good correlation with these quantitative data. MT was found to be expressed at a low level and in a patchy pattern in the gastrointestinal neoplastic and metastatic tissues, whereas in normal-appearing gastrointestinal mucosa MT was uniformly distributed in the cytoplasm and/or nucleus of apical cells. Although in the gastric cancer patients no association was found between the MT concentration and the clinicopathological parameters, the strong MT expression in areas with intestinal metaplasia, known to have neoplastic potential, further points to a relationship between this antioxidant metalloprotein and the malignant character of cells. Gastrointestinal neoplasms are apparently accompanied by a low level and decreased expression of MT, but those with a relatively high level seem to have an increased malignant potential. Further studies will be required to determine the clinical relevance of these observations.

Laparoscopic-assisted vs. open ileocolic resection for Crohn's disease. A comparative study

BACKGROUND

The objective of this study was to compare laparoscopic-assisted ileocolic resection for Crohn's disease of the distal ileum with open surgery in two consecutive groups of patients.

METHODS

From 1995 until 1998, 48 patients underwent open ileocolic resection at the Academic Medical Center (AMC) in Amsterdam, while 30 patients had laparoscopic-assisted ileocolic resection at the Leiden University Medical Center (LUMC). Patient characteristics, perioperative course, and recovery were compared. Differences between the groups were tested using Student's t-test for independent groups and chi-square tests when appropriate.

RESULTS

The open and the laparoscopic patient groups were comparable for age, gender, body mass index (BMI), prior abdominal surgery, and length of resected bowel. The conversion rate was 6.6%. Laparoscopic operating times (138+/-SD 36 min) were significantly longer than those observed in the open group (104+/-SD 34 min). Discharge was significantly earlier in the laparoscopic group than the open group (5.7 vs 10.2 postoperative days, p<0.007). Postoperative morbidity did not differ significantly between the patients treated traditionally (14.6%) and laparoscopically (10%).

CONCLUSION

Compared to open surgery, laparoscopic ileocolic resection for Crohn's disease is associated with similar morbidity rates, a shorter hospital stay, and improved cosmetic results, justifying the laparoscopic approach as the procedure of choice.

Superoxide dismutases in gastric and esophageal cancer and the prognostic impact in gastric cancer

The oxidant-antioxidant balance is thought to be important in the initiation, promotion, and therapy resistance of cancer. In the present study, we assessed the expression of the antioxidants manganese superoxide dismutase (Mn-SOD) and copper/zinc superoxide dismutase in gastric and esophageal carcinomas and their relation with clinical outcome. Adenocarcinomas of the stomach (n = 81) as well as squamous cell carcinomas of the esophagus (n = 10) showed an enhanced immunohistochemical expression of Mn-SOD, which was accompanied by a significantly higher tissue level (P < or = 0.007) compared with their corresponding normal mucosa. In contrast, copper/zinc superoxide dismutase was found to be marginally lower in these malignant tissues in comparison with the normal tissues. The superoxide dismutase levels were not found to be associated with major clinicopathological features of the gastric cancer patients. Univariate analysis revealed, however, that a high Mn-SOD level in gastric carcinomas, a low level in the normal gastric mucosa, and a high ratio of these two levels in gastric cancer patients are indicative of a poor overall survival. Multivariate analysis, including all clinicopathological parameters, revealed that the Mn-SOD ratio in particular is an independent prognostic parameter in gastric cancer patients.

Familial adenomatous polyposis: from bedside to bench and vice versa. A tribute to the somatic cell geneticist P. Meera Khan

Familial adenomatous polyposis (FAP) is characterized by the presence of numerous adenomatous polyps in the colorectum, as well as an autosomal dominant mode of inheritance. This syndrome will inevitably lead to colorectal cancer when left untreated, and it is estimated that 1% of all colorectal cancer cases are due to it. Over the past 20 years molecular genetic studies on FAP patients have laid down the basis for the elucidation of the genetic phenomena that ultimately result in the development of colorectal cancer. Professor P. Meera Khan was one of the leading authorities in the world of molecular genetics of colorectal cancer in general and of FAP in particular. His scientific contributions from the pre-DNA era up to the recent implementation of molecular genetic research in daily clinical practice have helped revolutionize our approach and management of FAP patients and their relatives.

Limited influence of pouch function on quality of life after ileal pouch-anal anastomosis

BACKGROUND/AIMS

Despite a high frequency of pouch function disorders, most patients are satisfied with the outcome of ileo-anal pouch surgery. Aims of this study were: 1) To assess the influence of pouch function on quality of life and, 2) to determine which aspects of pouch dysfunction affect quality of life the most.

METHODOLOGY

Questionnaires, addressing current pouch function and quality of life (Rand-36, GIQLI), were sent to all (53) patients with intact ileo-anal pouches, operated on between 1987 and 1997 in our center.

RESULTS

Thirty-six of 53 patients responded. Compared to reference data, Rand-36 scores for role-limitations based on a physical problem, vitality and general health perception were significantly diminished (P < 0.01). Physical and social functioning were normal. The GIQLI score was slightly decreased (111.7 vs. 125.8, P < 0.01). Overall pouch function did not correlate with the overall Rand-36 score, but correlated well with the overall GIQLI score (r = -0.47). Both quality of life scores were diminished mainly by the night-time stool frequency.

CONCLUSIONS

1) Quality of life after IPAA, as measured with validated questionnaires, is only slightly decreased; 2) the GIQLI questionnaire is more sensitive to pouch dysfunction than the Rand-36; 3) night-time stool frequency influences quality of life the most.

Nutritional control of nucleocytoplasmic localization of cAMP-dependent protein kinase catalytic and regulatory subunits in Saccharomyces cerevisiae

In budding yeast, cAMP-dependent protein kinase (PKA) plays a central role in the nutritional control of metabolism, cell cycle, and transcription. This study shows that both the regulatory subunit Bcy1p and the catalytic subunit Tpk1p associated with it are predominantly localized in the nucleus of rapidly growing cells. Activation of nuclear PKA by cAMP leads to fast entry of a significant part of Tpk1p into the cytoplasm, while the regulatory subunit remains nuclear. In contrast to rapidly proliferating cells, both Bcy1p and Tpk1p are distributed over nucleus and cytoplasm in cells growing on a nonfermentable carbon source or in stationary phase cells. These results demonstrate that at least two different mechanisms determine the subcellular localization of PKA; cAMP controls the localization of Tpk1p, and the carbon source determines that of Bcy1p. The N-terminal domain of Bcy1p serves to target it properly during logarithmic and stationary phase. Studies with Bcy1p mutant versions unable to concentrate in the nucleus revealed that cells producing them are less viable in stationary phase than wild type cells, display delayed reproliferation following transfer to fresh growth medium, and, as diploids, exhibit reduced efficiency of sporulation.

Mesalazine-induced apoptosis of colorectal cancer: on the verge of a new chemopreventive era?

BACKGROUND

It is an accepted fact that non-steroidal anti-inflammatory drugs (NSAIDs) are potent inhibitors of colorectal carcinogenesis. However, the major disadvantages of NSAIDs are gastrointestinal and renal toxicity. We conducted a prospective pilot study on the effects of the safe salicylic acid derivative, mesalazine, on apoptosis and proliferation of tumour cells and on normal tissue in colorectal cancer patients.

METHODS

Patients with colorectal cancer were asked to take mesalazine enemas for 14 days. Biopsies from malignant and normal tissue were taken prior to and after this treatment. Apoptosis was scored on haematoxylin/eosin-stained tissue sections, and cell proliferation was assessed by the proliferation marker Ki-67.

RESULTS

Ten out of 14 patients completed the study. The apoptotic score increased significantly in the tumour samples (pre-treatment 14.6 +/- 1.3 vs. post-treatment 19.4 +/- 0.8; P < 0.03). The apoptotic index in the normal mucosa was unchanged (pre-treatment 3.1 +/- 0.4 vs. post-treatment 2.9 +/- 0.3; N.S.). The cell proliferation in malignant tissue, according to the Ki-67 score, was hardly affected by mesalazine (pre-treatment 522 +/- 38 vs. post-treatment 493 +/- 39; N.S.). There was no effect on the Ki-67 index of normal mucosa (pre-treatment 24.2 +/- 2.0 vs. post-treatment 28.3 +/- 2.0; N.S.).

CONCLUSIONS

This pilot study conducted in patients with colorectal cancer clearly shows that mesalazine selectively induces apoptosis of tumour cells. On the basis of these findings, which need to be confirmed in larger studies, it may be speculated that 5-ASA could be useful in the chemoprevention of colorectal cancer.

Treatment of mesenteric desmoid tumours with the anti-oestrogenic agent toremifene: case histories and an overview of the literature

Desmoid tumours are histologically benign but due to their infiltration and compression of surrounding structures potentially life-threatening fibromatous lesions of unknown aetiology. The annual incidence rate is 2-4 per million people. The mesenteric variant constitutes about 10% of all desmoid tumours, although in familial adenomatous polyposis (FAP) patients this may be up to 70%. Due to the small number of patients with mesenteric desmoids the therapy is mainly empirical. This report describes the rationale as well as the value of the short- and long-term treatment (up to 6 years) with the anti-oestrogenic agent toremifene in combination with sulindac in two patients suffering from such a mesenteric desmoid tumour. These patients did not respond to sulindac alone and previous treatment with tamoxifen together with this non-steroidal anti-inflammatory drug had also failed. An overview of the literature on the management of these dismal tumours is presented.

Azathioprine: an update on clinical efficacy and safety in inflammatory bowel disease

BACKGROUND

The approval of azathioprine (AZA) for the long-term therapy of patients with Crohn's disease in The Netherlands.

METHODS

Review and update of the literature on clinical efficacy and safety of AZA in inflammatory bowel disease.

RESULTS

AZA and its metabolite 6-mercaptopurine (6-MP) are effective in the treatment of active Crohn's disease. However, the onset of the clinical response is delayed, requiring combination with other active medication in the early phase of treatment. Maintenance therapy with AZA/6-MP is also effective in the prevention of relapses in patients with Crohn's disease in remission. Indications for AZA/6-MP therapy further include refractory, fistulizing and steroid-dependent Crohn's disease. It is not known whether or when AZA/6-MP can be withdrawn in patients in long-term remission, but most clinicians discontinue therapy after 3-5 years. Although fewer data are available, AZA/6-PM appears to be effective also in the therapy of patients with ulcerative colitis. Side effects of AZA/6-MP occur in about 15% of patients and include skin rash, pancreatitis and hepatitis, dose-related neutropenia and thrombocytopenia, and risk of increased occurrence and severity of infections. Recent data suggest that the risk of malignancy, other than colorectal cancer, is not increased. Safety in pregnancy has not been studied extensively, but no increased prevalence of birth defects has been reported.

CONCLUSIONS

AZA/6-MP therapy is efficacious in patients with active Crohn's disease, but the drug is especially valuable in the long-term treatment of patients with Crohn's disease and ulcerative colitis. Drug-related side effects are frequent and require discontinuation or dose-reduction of the AZA/6-MP therapy. Due to an increased risk of infections secondary to myelosuppression, careful follow-up is mandatory. Insufficient data are available on safety in pregnancy and on the risk of malignancies, but the limited data available in patients with inflammatory bowel disease appear to be reassuring.

Laparoscopically assisted bowel surgery for inflammatory bowel disease. The combined experiences of two academic centers

BACKGROUND

Laparoscopic bowel surgery was evaluated in 44 consecutive patients who underwent surgery for inflammatory bowel disease (IBD). We studied feasibility, results, and final outcome.

METHODS

At two academic institutes, 44 laparoscopically assisted colectomies and laparoscopic ileostomies or colostomies were attempted. All patients had histologically proven IBD and no prior surgery for IBD. Loop ileostomy (n = 4), end colostomy (n = 1), ileocecal resection (n = 26) and (procto)colectomy (n = 13) were performed. All resections were laparoscopically assisted with extracorporal resection and anastomosis.

RESULTS

Only in two patients (ileocecal resection in both) was conversion to open surgery necessary. Two patients with laparoscopic ileocolic resection had intra-abdominal abscesses, which were drained percutaneously in both. One patient in the laparoscopically assisted colectomy group had a subphrenic abscess that was drained percutaneously, and one patient had a generalized candidiasis.

CONCLUSIONS

Laparoscopically assisted colectomies can be performed safely in treating IBD. The laparoscopic method with use of a small vertical umbilical or Pfannenstiel's incision seems acceptable with regard to operating time and overall costs, also allowing superior cosmesis to be maintained.

Superoxide dismutases in the human colorectal cancer sequence

PURPOSE

The oxidant-antioxidant balance within tissues is thought to contribute to the development and progression of cancer. Previous investigations have indicated changes in this balance during the colorectal oncogenic process that merit further investigation. The aim of the present study was to evaluate whether the human colorectal cancer sequence is accompanied by changes in the protein and activity levels of the antioxidant enzymes manganese- and copper/zinc-superoxide dismutase (Mn-SOD and Cu/Zn-SOD).

PATIENTS AND METHODS

SOD levels were assessed in colorectal adenomas, carcinomas, and liver metastases and were compared with those in the corresponding normal tissues (n = 35 in each group). Mn- and Cu/Zn-SOD expression was first evaluated semiquantitatively by electrophoretic activity analysis, immunoblotting, and immunohistochemistry and was subsequently quantified by enzyme-linked immunosorbent assays (ELISAs) and spectrophotometric activity assays.

RESULTS

The semiquantitative analyses showed enhanced Mn-SOD levels, primarily localized in (neoplastic) epithelial cells, in carcinomas, and in liver metastases as compared with adenomas and normal mucosa, whereas no consistent pattern was observed for Cu/Zn-SOD. Normal liver tissue expressed the highest levels of both SODs. The quantitative SOD analyses confirmed these observations and revealed that carcinomas and liver metastases expressed 2-4 times more Mn-SOD protein and enzymatic activity (0.0005 < P < 0.01) than did the normal mucosa. Adenomas expressed intermediate Mn-SOD levels, which increased significantly with the diameter and tended to increase with the grade of dysplasia and presence of a villous component. In contrast, adenomas, carcinomas, and the corresponding normal mucosa were found to have a similar Cu/Zn-SOD content, whereas liver metastases contained significantly (P < 0.02) more Cu/Zn-SOD as compared with these tissues. In addition, the Cu/Zn-SOD content was not related to any histopathological characteristic of the carcinomas or adenomas.

CONCLUSIONS

Our study indicates that the development of neoplasia in the human colorectum is accompanied by major changes in the level and activity of Mn-SOD. This observation illustrates that Mn-SOD might have a functional role in human colorectal carcinogenesis.