Erik Hertervig

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

Aliment Pharmacol Ther 2010; 32: 984–989

Alkaline sphingomyelinase activity is decreased in human colorectal carcinoma

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.

Distribution of alkaline sphingomyelinase activity in human beings and animals : Tissue and species differences

The alkaline sphingomyelinase (SMase) was first found in rat intestinal brush border. The important roles of this enzyme in digestion of sphingomyelin and in mucosal cell proliferation have been suggested. In the present work, the distribution of the alkaline SMase in the tissues of human beings and animals have been studied. By assaying the enzyme activity in human biopsy samples, we found that the alkaline SMase activity was absent in the stomach, increased in the duodenum, present at high levels in the small intestine, and slightly declined in the colon and rectum. High activities were found similarly in the intestinal contents of the healthy adults and infants. The activities were also found in the intestinal mucosa of rats, normal and germ-free mice, and hamsters with the same distribution pattern as in humans, but not in the intestinal mucosa of guinea pigs. Apart from the intestinal tract, a SMase activity preferring alkaline pH was identified in human and guinea pig bile, but not in the bile of rat, pig, sheep, and cow. No activity was found in either pancreatic tissue or pancreatic juice in all species tested, and none was detected in human urine and milk. In conclusion, alkaline SMase exists predominantly in the digestive system with considerable tissue and species differences.

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.

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.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.

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

SummaryThe 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.

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

Background and AimsThe 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. MethodsAlkaline 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. ResultsAlkaline 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). ConclusionsReduction 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.

Anti-neutrophil cytoplasmic antibodies in chronic inflammatory bowel disease. Prevalence and diagnostic role

BACKGROUND Anti-neutrophil cytoplasmic antibodies (ANCA), originally found to be associated with vasculitis, have been reported to be present in chronic inflammatory bowel disease. Most often the ANCA staining pattern is of the perinuclear type (p-ANCA), although nuclear and cytoplasmic stainings are seen. Single studies have shown some of the antibodies to react with lactoferrin or cathepsin G; however, most studies have not been able to determine a main antigenic specificity. We studied the prevalence of ANCA in sera from 155 patients with ulcerative colitis, 128 patients with Crohns disease, and 51 patients with coeliac disease. The presence of ANCA was correlated to disease activity, extent, and age of onset of the diseases. Furthermore, we tried to characterize the antigen specificity by enzyme-linked immunosorbent assay (ELISA), using elastase, lactoferrin, myeloperoxidase, proteinase 3, and cathepsin G as antigens. METHODS The sera were screened for ANCA by indirect immunofluorescence. Anti-nuclear antibodies (ANA) were analysed on HEp2 cells, and ELISA for specific ANCA was performed using the antigens mentioned. RESULTS Most of the sera with positive immunofluorescence had the p-ANCA type of pattern. Seventy-eight of 155 (50.3%) of the patients with ulcerative colitis were ANCA-positive, compared with 31 of 128 (24.2%) of patients with Crohns disease (p < 0.001). However, in the subgroup with Crohns colitis, 16 of 44 (36.4%) were ANCA-positive. Only 4 of 51 patients (7.7%) with coeliac disease showed positive immunofluorescence (p < 0.001 compared with ulcerative colitis). Less than 10% of the samples were positive in the specific ELISA assays; thus other than the most well known granule proteins can be the target for ANCA in ulcerative colitis. CONCLUSION ANCA occur significantly more often in ulcerative colitis than in Crohns disease. However, the prevalence of ANCA is rather high in Crohns colitis. ANCA are thus of limited value in differentiating Crohns colitis from ulcerative colitis. ANCA found in inflammatory bowel disease are different from those associated with vasculitis. The antigen(s) responsible remain to be determined.

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.

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

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.