Karen Lammers - Academia.edu (original) (raw)

Papers by Karen Lammers

The Netherlands Journal of Medicine, 1996

PloS one, 2015

Gliadin, the immunogenic component within gluten and trigger of celiac disease, is known to induc... more Gliadin, the immunogenic component within gluten and trigger of celiac disease, is known to induce the production of Interleukin-8, a potent neutrophil-activating and chemoattractant chemokine. We sought to study the involvement of neutrophils in the early immunological changes following gliadin exposure. Utilizing immunofluorescence microscopy and flow cytometry, the redistribution of major tight junction protein, Zonula occludens (ZO)-1, and neutrophil recruitment were assessed in duodenal tissues of gliadin-gavaged C57BL/6 wild-type and Lys-GFP reporter mice, respectively. Intravital microscopy with Lys-GFP mice allowed monitoring of neutrophil recruitment in response to luminal gliadin exposure in real time. In vitro chemotaxis assays were used to study murine and human neutrophil chemotaxis to gliadin, synthetic alpha-gliadin peptides and the neutrophil chemoattractant, fMet-Leu-Phe, in the presence or absence of a specific inhibitor of the fMet-Leu-Phe receptor-1 (FPR1), cyclo...

ChemistryOpen, Mar 1, 2018

Gluten-related disorders are a complex group of diseases that involve the activation of the immun... more Gluten-related disorders are a complex group of diseases that involve the activation of the immune system triggered by the ingestion of gluten. Among these, celiac disease, with a prevalence of 1 %, is the most investigated, but recently, a new pathology, named nonceliac gluten sensitivity, was reported with a general prevalence of 7 %. Finally, there other less-prevalent gluten-related diseases such as wheat allergy, gluten ataxia, and dermatitis herpetiformis (with an overall prevalence of less than 0.1 %). As mentioned, the common molecular trigger is gluten, a complex mixture of storage proteins present in wheat, barley, and a variety of oats that are not fully degraded by humans. The most-studied protein related to disease is gliadin, present in wheat, which possesses in its sequence many pathological fragments. Despite a lot of effort to treat these disorders, the only effective method is a long-life gluten-free diet. This Review summarizes the actual knowledge of gluten-relat...

World Journal of Gastroenterology, 2006

AIM: To evaluate the intestinal motility changes evoked by 8 bacterial strains belonging to Bifid... more AIM: To evaluate the intestinal motility changes evoked by 8 bacterial strains belonging to Bifidobacterium , Lactobacillus and Streptococcus genera within the probiotic preparation VSL#3. METHODS: Ileum and proximal colon segments isolated from guinea-pigs were used as a study model. Entire cells and cell fractions (cell debris, cell wall fraction, cytoplasmatic fraction, proteinaceous and nonproteinaceous cytoplasmatic components) of VSL#3 strains and, as controls, Escherichia coli, Salmonella aboni and Bacillus licheniformis were tested in this in vitro model. RESULTS: Among the bacterial cell fractions tested, only the cytoplasmatic fraction modified intestinal motility. Lactobacillus strains stimulated the contraction of ileum segment, whereas all probiotic strains tested induced proximal colon relaxation response. The non-proteinaceous cytoplasmatic components were responsible for the colon relaxation. CONCLUSION: The results obtained in this study suggest that the proximal colon relaxation activity showed by the probiotic bacteria could be one of the possible mechanisms of action by which probiotics exert their positive effects in regulating intestinal motility.

World Journal of Gastroenterology, 2006

AIM: To investigate whether the stimulation of peripheral blood mononuclear cells (PBMNC) with th... more AIM: To investigate whether the stimulation of peripheral blood mononuclear cells (PBMNC) with the cell debris and cell extraction of different probiotic strains is similar or species specific. METHODS: Three strains of bifidobacteria , 4 strains of lactobacilli , and E. coli nissle were sonicated and centrifuged in order to divide them into cell extract and cell debris. PBMNC were separated by density gradient and incubated for 36 h with either the cell debris or the cell extract of single strains of probiotic bacteria in doses from 10 2 to 10 8 CFU/mL. Cell supernatants were taken and interleukin (IL)-10, IL-1β, and tumor necosis factor (TNF)-α were determined by ELISA. RESULTS: Depending on the species super-family, the strains had different stimulation patterns. Except for both L. casei strains, the cell extract of bifidobacteria and lactobacilli had less stimulating capacity than cell debris, whereas the cell extract of E. coli nissle had similar stimulating properties to that of the cell debris of the strain and significantly more stimulating capacity than that of bifidobacteria and lactobacilli. The cell debris of bifidobacteria stimulated more cytokine release than the cell debris of lactobacilli. The cell debris of lactobacilli did not have a stimulating capacity when lower concentrations were used. Neither cell extraction nor cell debris had an inhibitory effect on the production of the tested cytokines by stimulated PBMNC. CONCLUSION: The incubation of probiotic strains, which have been used in clinical trials for inflammatory diseases, with immunocompetent cells leads to different species specific reactions. High IL-10 response to cell debris of bifidobacteria and E. coli nissle can be found. This corresponds to positive effects of bifidobacteria and E. coli nissle in clinical trials for inflammatory bowel disease compared to negative outcomes obtained with lactobacilli .

The American journal of gastroenterology, 2002

Promising results from clinical studies on the effect of probiotics as maintenance therapy in inf... more Promising results from clinical studies on the effect of probiotics as maintenance therapy in inflammatory bowel disease and in the prevention of onset of pouchitis ask for studies to unravel the still poorly understood mechanism of action of probiotics. To evaluate whether the probiotic bacteria that were used in the clinical studies (VSL#3, Escherichia coli Nissle 1917, and Lactobacillus GG) are able to induce chemokine production in epithelial cells, HT29/19A monolayers were incubated with cell debris and cell extract fractions of single strains of the probiotic bacteria in doses ranging from 10(3) to 10(9) colony-forming units/ml for 32 h. Supernatants were measured for interleukin 8 by ELISA. Lactobacilli and bifidobacteria strains from VSL#3 and Lactobacillus GG did not induce interleukin 8, whereas both cell debris and cell extracts from E. coli Nissle 1917 induced interleukin 8 production in a dose-dependent way. Cell extracts from streptococcal strains induced interleukin 8...

Immunology, 1994

Interaction of CD28 with its ligand B7 plays an important role in the initiation of immune respon... more Interaction of CD28 with its ligand B7 plays an important role in the initiation of immune responses. The co-stimulatory signal generated by cross-linking of CD28 molecules results in enhanced T-cell proliferation and augmentation of cytokine production. In particular, mRNA levels of T-helper 1 (Th1)-type cytokines, such as interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) are reported to be strongly increased. We investigated the effect of CD28 co-stimulation on the production of Th2-type cytokines. CD28 mAb induced a strong augmentation of IL-2 secretion in activated T-cell clones. Production of IFN-gamma was also enhanced, but the increase in IL-4 secretion was generally moderate. Augmentation of IL-4 production by CD28 was most pronounced in clones that produced low amounts of IL-2, compared to clones producing high levels of IL-2. It was found that the up-regulation of IL-4 by CD28 co-stimulation was mainly controlled indirectly via an increase of IL-2. Some clones could pr...

Frontiers in Immunology, 2013

Typhoid fever, caused by S. Typhi, is responsible for approximately 200,000 deaths per year world... more Typhoid fever, caused by S. Typhi, is responsible for approximately 200,000 deaths per year worldwide. Little information is available regarding epithelium-bacterial interactions in S. Typhi infection. We have evaluated in vitro the effects of wild-type S. Typhi, the licensed Ty21a typhoid vaccine and the leading strains CVD 908-htrA and CVD 909 vaccine candidates on intestinal barrier function and immune response. Caco2 monolayers infected with wild-type S.Typhi exhibited alterations in the organization of tight junctions, increased paracellular permeability, and a rapid decrease in Trans-Epithelial Electrical Resistance as early as 4 h post-exposure. S. Typhi triggered the secretion of interleukin (IL)-8 and IL-6. Caco2 cells infected with the attenuated strains exhibited a milder pro-inflammatory response with minimal disruption of the barrier integrity. We conclude that wild-type S. Typhi causes marked transient alterations of the intestinal mucosa that are more pronounced than those observed with Ty21a or new generation attenuated typhoid vaccine candidates.

C36. LUNG EPITHELIUM, SUBMUCOSAL GLANDS AND SMOOTH MUSCLE, 2012

Gastroenterology, 2011

ponding to subdivisions of the 33mer based on the ability of ALV001 to cut several times within t... more ponding to subdivisions of the 33mer based on the ability of ALV001 to cut several times within this gluten epitope. RESULTS: Mass spectrometry detected 33mer and all five peptide fragments resulting from degradation of the 33mer by ALV001. A large linear range was observed, with detection as low as 1 ng/ml of the peptides of interest. Intraday coefficient of variability was typically less than 5%. ALV001 cut within the 33mer epitope in the context of wheat gluten, releasing all five fragments that initially rose in concentration but plateaued as ALV001-mediated degradation slows. Using a clinical dose (150 mg, 0.3 mg/ml), ALV001 degraded 98% (10 minutes) and 99.5% (30 minutes) of the 33mer epitope. ALV001 and ALV002 functioned cooperatively; ALV002 degraded the five relatively stable peptide fragments as ALV001 activity plateaued. SUMMARY: A mass spectrometry assay was established to quantify the ability of ALV003 to degrade 33mer within wheat bread gluten in the context of a complex meal. Using this methodology, it was possible to distinguish separate but complementary contributions of ALV001 and ALV002 to 33mer degradation. The data support a model for ALV003-mediated gluten degradation in which ALV001 rapidly cleaves gluten adjacent to glutamine residues, releasing small proline-rich peptide fragments that serve as substrates for the prolyl endopeptidase ALV002. Data from a simulated gastric environment suggest that ALV003 should degrade ingested gluten in patients with celiac disease.

Journal of Pediatric Gastroenterology and Nutrition, 2006

International Journal of Colorectal Disease, 2003

International Journal of Antimicrobial Agents, 2009

Inflammatory Bowel Diseases, 2005

Immunology, 2010

The autoimmune enteropathy, coeliac disease (CD), is triggered by ingestion of gluten-containing ... more The autoimmune enteropathy, coeliac disease (CD), is triggered by ingestion of gluten-containing grains. We recently reported that the chemokine receptor CXCR3 serves as a receptor for specific gliadin peptides that cause zonulin release and subsequent increase in intestinal permeability. To explore the role of CXCR3 in the immune response to gliadin, peripheral blood mononuclear cells from both patients with CD and healthy controls were incubated with either pepsin-trypsin-digested gliadin or 11 a-gliadin synthetic peptides in the presence or absence of a blocking anti-CXCR3 monoclonal antibody. Supernatants were analysed for interleukin-6 (IL-6), IL-8, IL-10, IL-13, IP-10 (CXCL10), tumour necrosis factor-a and interferon-c. Gliadin broadly induced cytokine production irrespective of the clinical condition. However, IL-8 production occurred only in a subgroup of individuals and cells of the phagocytic lineage were the main source. Induction of IL-8 was reproduced by one of a comprehensive panel of synthetic a-gliadin peptides and was abrogated when CXCR3 was blocked before stimulation with either gliadin or this peptide in the CD group but not in the control group, suggesting that gliadin-induced IL-8 production was CXCR3-dependent gliadin induced IL-8 production only in CD.

Gut, 2000

DiVerential expression of cyclooxygenase 2 in human colorectal cancer EDITOR,-We were puzzled by ... more DiVerential expression of cyclooxygenase 2 in human colorectal cancer EDITOR,-We were puzzled by the recent paper by Dimberg and colleagues (Gut 1999;45:730-732) which reported that upregulation of cyclooxygenase 2 (COX-2) protein expression was prominent in rectal adenocarcinomas compared with that in adenocarcinomas arising from the colon. "Low or undetectable levels of COX-2 protein expression" were demonstrated in 15 of 19 colonic adenocarcinomas located proximal to the rectum. Overall, upregulation of COX-2 protein expression was reported in only 56% of colorectal cancers. Previous reports, 1-7 which include one by the current authors on a not dissimilar case series, 1 and two in the joint authorship of the accompanying commentary writer, 2 3 have shown consistent upregulation of COX-2 expression in colonic and rectal adenocarcinomas (in 85-90% of cases) compared with matched normal colonic mucosa using diVerent techniques, including northern blot analysis, RT-PCR, western blot analysis, and immunohistochemistry. Furthermore, four of these studies refer to the distribution of adenocarcinomas throughout the colon without showing evidence of diVerential COX-2 expression between rectal and more proximal tumours. 1 2 4 5 In the one previous study which analysed COX-2 protein expression in human colorectal cancers by western blot analysis, 7 immunoreactive COX-2 was detected in 76% of cases with a 10-fold increase in median tissue COX-2 concentration compared with normal colonic mucosa. In our view, the authors should attempt to explain the discrepancy between their results and previously published data. It is interesting to note that, in the study of Kargman et al, five of six patients taking NSAIDs had low or undetectable COX-2 protein expression. 7 Moreover, aspirin has recently been shown to suppress induction of COX-2 mRNA and protein in interleukin-1 and phorbol ester stimulated human endothelial cells and fibroblasts. 8 Do the authors have data on NSAID use in their cohort of patients prior to surgery?

Gastroenterology, 2014

Intestinal villi provide an enormous surface area for nutrient absorption. Significant loss of in... more Intestinal villi provide an enormous surface area for nutrient absorption. Significant loss of intestinal surface area can compromise intestinal function, causing intestinal failure. Though short-term treatments for this life-threatening condition are available, all patients need lifelong monitoring for growth and nutritional status, and would benefit from treatments that can directly increase intestinal surface area. In mice, a large increase in surface area occurs with villus development, which begins at embryonic day (E)14.5, when the thick pseudostratified epithelium with a flat luminal surface is converted to a columnar epithelium covering a field of emerging villi. Though it has long been thought that epithelial remodeling occurs by formation and fusion of secondary lumina, recent work in our laboratory showed that secondary lumina do not exist (Grosse et al., Development 138:4423, 2011). Seeking an alternative mechanism for luminal expansion, we found a unique type of cell division that is triggered specifically at E14.5, which we have named an e-division (lumen extending division). We propose that in an e-division, new apical surface is deposited at the cytokinetic plane such that the two daughter cells segregate onto adjacent villi. The e-division is distinct from cell divisions occurring before E14.5, which we have named g-divisions (girth building divisions); g-divisions do not involve deposition of new apical surface between daughter cells. Our data (lineage tracing, 3D reconstruction, and SEM) suggest that in mice deficient in the apical surface protein Ezrin, e-divisions fail stochastically, resulting in fused villi. We are modeling e-divisions in vitro using MDCK and Caco2 cell lines, which form luminal surfaces during the first cell division when plated in a 3D matrix. Using RNA interference, we have found that reducing Ezrin expression compromises lumen formation in our 3D cyst assay, providing a mechanistic explanation for the presence of fused villi in vivo. Further understanding of the process of villus development will improve in vitro bioengineering of intestinal surface, potentially yielding novel therapies for those with intestinal failure.

The Netherlands Journal of Medicine, 1996

PloS one, 2015

Gliadin, the immunogenic component within gluten and trigger of celiac disease, is known to induc... more Gliadin, the immunogenic component within gluten and trigger of celiac disease, is known to induce the production of Interleukin-8, a potent neutrophil-activating and chemoattractant chemokine. We sought to study the involvement of neutrophils in the early immunological changes following gliadin exposure. Utilizing immunofluorescence microscopy and flow cytometry, the redistribution of major tight junction protein, Zonula occludens (ZO)-1, and neutrophil recruitment were assessed in duodenal tissues of gliadin-gavaged C57BL/6 wild-type and Lys-GFP reporter mice, respectively. Intravital microscopy with Lys-GFP mice allowed monitoring of neutrophil recruitment in response to luminal gliadin exposure in real time. In vitro chemotaxis assays were used to study murine and human neutrophil chemotaxis to gliadin, synthetic alpha-gliadin peptides and the neutrophil chemoattractant, fMet-Leu-Phe, in the presence or absence of a specific inhibitor of the fMet-Leu-Phe receptor-1 (FPR1), cyclo...

ChemistryOpen, Mar 1, 2018

Gluten-related disorders are a complex group of diseases that involve the activation of the immun... more Gluten-related disorders are a complex group of diseases that involve the activation of the immune system triggered by the ingestion of gluten. Among these, celiac disease, with a prevalence of 1 %, is the most investigated, but recently, a new pathology, named nonceliac gluten sensitivity, was reported with a general prevalence of 7 %. Finally, there other less-prevalent gluten-related diseases such as wheat allergy, gluten ataxia, and dermatitis herpetiformis (with an overall prevalence of less than 0.1 %). As mentioned, the common molecular trigger is gluten, a complex mixture of storage proteins present in wheat, barley, and a variety of oats that are not fully degraded by humans. The most-studied protein related to disease is gliadin, present in wheat, which possesses in its sequence many pathological fragments. Despite a lot of effort to treat these disorders, the only effective method is a long-life gluten-free diet. This Review summarizes the actual knowledge of gluten-relat...

World Journal of Gastroenterology, 2006

AIM: To evaluate the intestinal motility changes evoked by 8 bacterial strains belonging to Bifid... more AIM: To evaluate the intestinal motility changes evoked by 8 bacterial strains belonging to Bifidobacterium , Lactobacillus and Streptococcus genera within the probiotic preparation VSL#3. METHODS: Ileum and proximal colon segments isolated from guinea-pigs were used as a study model. Entire cells and cell fractions (cell debris, cell wall fraction, cytoplasmatic fraction, proteinaceous and nonproteinaceous cytoplasmatic components) of VSL#3 strains and, as controls, Escherichia coli, Salmonella aboni and Bacillus licheniformis were tested in this in vitro model. RESULTS: Among the bacterial cell fractions tested, only the cytoplasmatic fraction modified intestinal motility. Lactobacillus strains stimulated the contraction of ileum segment, whereas all probiotic strains tested induced proximal colon relaxation response. The non-proteinaceous cytoplasmatic components were responsible for the colon relaxation. CONCLUSION: The results obtained in this study suggest that the proximal colon relaxation activity showed by the probiotic bacteria could be one of the possible mechanisms of action by which probiotics exert their positive effects in regulating intestinal motility.

World Journal of Gastroenterology, 2006

AIM: To investigate whether the stimulation of peripheral blood mononuclear cells (PBMNC) with th... more AIM: To investigate whether the stimulation of peripheral blood mononuclear cells (PBMNC) with the cell debris and cell extraction of different probiotic strains is similar or species specific. METHODS: Three strains of bifidobacteria , 4 strains of lactobacilli , and E. coli nissle were sonicated and centrifuged in order to divide them into cell extract and cell debris. PBMNC were separated by density gradient and incubated for 36 h with either the cell debris or the cell extract of single strains of probiotic bacteria in doses from 10 2 to 10 8 CFU/mL. Cell supernatants were taken and interleukin (IL)-10, IL-1β, and tumor necosis factor (TNF)-α were determined by ELISA. RESULTS: Depending on the species super-family, the strains had different stimulation patterns. Except for both L. casei strains, the cell extract of bifidobacteria and lactobacilli had less stimulating capacity than cell debris, whereas the cell extract of E. coli nissle had similar stimulating properties to that of the cell debris of the strain and significantly more stimulating capacity than that of bifidobacteria and lactobacilli. The cell debris of bifidobacteria stimulated more cytokine release than the cell debris of lactobacilli. The cell debris of lactobacilli did not have a stimulating capacity when lower concentrations were used. Neither cell extraction nor cell debris had an inhibitory effect on the production of the tested cytokines by stimulated PBMNC. CONCLUSION: The incubation of probiotic strains, which have been used in clinical trials for inflammatory diseases, with immunocompetent cells leads to different species specific reactions. High IL-10 response to cell debris of bifidobacteria and E. coli nissle can be found. This corresponds to positive effects of bifidobacteria and E. coli nissle in clinical trials for inflammatory bowel disease compared to negative outcomes obtained with lactobacilli .

The American journal of gastroenterology, 2002

Promising results from clinical studies on the effect of probiotics as maintenance therapy in inf... more Promising results from clinical studies on the effect of probiotics as maintenance therapy in inflammatory bowel disease and in the prevention of onset of pouchitis ask for studies to unravel the still poorly understood mechanism of action of probiotics. To evaluate whether the probiotic bacteria that were used in the clinical studies (VSL#3, Escherichia coli Nissle 1917, and Lactobacillus GG) are able to induce chemokine production in epithelial cells, HT29/19A monolayers were incubated with cell debris and cell extract fractions of single strains of the probiotic bacteria in doses ranging from 10(3) to 10(9) colony-forming units/ml for 32 h. Supernatants were measured for interleukin 8 by ELISA. Lactobacilli and bifidobacteria strains from VSL#3 and Lactobacillus GG did not induce interleukin 8, whereas both cell debris and cell extracts from E. coli Nissle 1917 induced interleukin 8 production in a dose-dependent way. Cell extracts from streptococcal strains induced interleukin 8...

Immunology, 1994

Interaction of CD28 with its ligand B7 plays an important role in the initiation of immune respon... more Interaction of CD28 with its ligand B7 plays an important role in the initiation of immune responses. The co-stimulatory signal generated by cross-linking of CD28 molecules results in enhanced T-cell proliferation and augmentation of cytokine production. In particular, mRNA levels of T-helper 1 (Th1)-type cytokines, such as interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) are reported to be strongly increased. We investigated the effect of CD28 co-stimulation on the production of Th2-type cytokines. CD28 mAb induced a strong augmentation of IL-2 secretion in activated T-cell clones. Production of IFN-gamma was also enhanced, but the increase in IL-4 secretion was generally moderate. Augmentation of IL-4 production by CD28 was most pronounced in clones that produced low amounts of IL-2, compared to clones producing high levels of IL-2. It was found that the up-regulation of IL-4 by CD28 co-stimulation was mainly controlled indirectly via an increase of IL-2. Some clones could pr...

Frontiers in Immunology, 2013

Typhoid fever, caused by S. Typhi, is responsible for approximately 200,000 deaths per year world... more Typhoid fever, caused by S. Typhi, is responsible for approximately 200,000 deaths per year worldwide. Little information is available regarding epithelium-bacterial interactions in S. Typhi infection. We have evaluated in vitro the effects of wild-type S. Typhi, the licensed Ty21a typhoid vaccine and the leading strains CVD 908-htrA and CVD 909 vaccine candidates on intestinal barrier function and immune response. Caco2 monolayers infected with wild-type S.Typhi exhibited alterations in the organization of tight junctions, increased paracellular permeability, and a rapid decrease in Trans-Epithelial Electrical Resistance as early as 4 h post-exposure. S. Typhi triggered the secretion of interleukin (IL)-8 and IL-6. Caco2 cells infected with the attenuated strains exhibited a milder pro-inflammatory response with minimal disruption of the barrier integrity. We conclude that wild-type S. Typhi causes marked transient alterations of the intestinal mucosa that are more pronounced than those observed with Ty21a or new generation attenuated typhoid vaccine candidates.

C36. LUNG EPITHELIUM, SUBMUCOSAL GLANDS AND SMOOTH MUSCLE, 2012

Gastroenterology, 2011

ponding to subdivisions of the 33mer based on the ability of ALV001 to cut several times within t... more ponding to subdivisions of the 33mer based on the ability of ALV001 to cut several times within this gluten epitope. RESULTS: Mass spectrometry detected 33mer and all five peptide fragments resulting from degradation of the 33mer by ALV001. A large linear range was observed, with detection as low as 1 ng/ml of the peptides of interest. Intraday coefficient of variability was typically less than 5%. ALV001 cut within the 33mer epitope in the context of wheat gluten, releasing all five fragments that initially rose in concentration but plateaued as ALV001-mediated degradation slows. Using a clinical dose (150 mg, 0.3 mg/ml), ALV001 degraded 98% (10 minutes) and 99.5% (30 minutes) of the 33mer epitope. ALV001 and ALV002 functioned cooperatively; ALV002 degraded the five relatively stable peptide fragments as ALV001 activity plateaued. SUMMARY: A mass spectrometry assay was established to quantify the ability of ALV003 to degrade 33mer within wheat bread gluten in the context of a complex meal. Using this methodology, it was possible to distinguish separate but complementary contributions of ALV001 and ALV002 to 33mer degradation. The data support a model for ALV003-mediated gluten degradation in which ALV001 rapidly cleaves gluten adjacent to glutamine residues, releasing small proline-rich peptide fragments that serve as substrates for the prolyl endopeptidase ALV002. Data from a simulated gastric environment suggest that ALV003 should degrade ingested gluten in patients with celiac disease.

Journal of Pediatric Gastroenterology and Nutrition, 2006

International Journal of Colorectal Disease, 2003

International Journal of Antimicrobial Agents, 2009

Inflammatory Bowel Diseases, 2005

Immunology, 2010

The autoimmune enteropathy, coeliac disease (CD), is triggered by ingestion of gluten-containing ... more The autoimmune enteropathy, coeliac disease (CD), is triggered by ingestion of gluten-containing grains. We recently reported that the chemokine receptor CXCR3 serves as a receptor for specific gliadin peptides that cause zonulin release and subsequent increase in intestinal permeability. To explore the role of CXCR3 in the immune response to gliadin, peripheral blood mononuclear cells from both patients with CD and healthy controls were incubated with either pepsin-trypsin-digested gliadin or 11 a-gliadin synthetic peptides in the presence or absence of a blocking anti-CXCR3 monoclonal antibody. Supernatants were analysed for interleukin-6 (IL-6), IL-8, IL-10, IL-13, IP-10 (CXCL10), tumour necrosis factor-a and interferon-c. Gliadin broadly induced cytokine production irrespective of the clinical condition. However, IL-8 production occurred only in a subgroup of individuals and cells of the phagocytic lineage were the main source. Induction of IL-8 was reproduced by one of a comprehensive panel of synthetic a-gliadin peptides and was abrogated when CXCR3 was blocked before stimulation with either gliadin or this peptide in the CD group but not in the control group, suggesting that gliadin-induced IL-8 production was CXCR3-dependent gliadin induced IL-8 production only in CD.

Gut, 2000

DiVerential expression of cyclooxygenase 2 in human colorectal cancer EDITOR,-We were puzzled by ... more DiVerential expression of cyclooxygenase 2 in human colorectal cancer EDITOR,-We were puzzled by the recent paper by Dimberg and colleagues (Gut 1999;45:730-732) which reported that upregulation of cyclooxygenase 2 (COX-2) protein expression was prominent in rectal adenocarcinomas compared with that in adenocarcinomas arising from the colon. "Low or undetectable levels of COX-2 protein expression" were demonstrated in 15 of 19 colonic adenocarcinomas located proximal to the rectum. Overall, upregulation of COX-2 protein expression was reported in only 56% of colorectal cancers. Previous reports, 1-7 which include one by the current authors on a not dissimilar case series, 1 and two in the joint authorship of the accompanying commentary writer, 2 3 have shown consistent upregulation of COX-2 expression in colonic and rectal adenocarcinomas (in 85-90% of cases) compared with matched normal colonic mucosa using diVerent techniques, including northern blot analysis, RT-PCR, western blot analysis, and immunohistochemistry. Furthermore, four of these studies refer to the distribution of adenocarcinomas throughout the colon without showing evidence of diVerential COX-2 expression between rectal and more proximal tumours. 1 2 4 5 In the one previous study which analysed COX-2 protein expression in human colorectal cancers by western blot analysis, 7 immunoreactive COX-2 was detected in 76% of cases with a 10-fold increase in median tissue COX-2 concentration compared with normal colonic mucosa. In our view, the authors should attempt to explain the discrepancy between their results and previously published data. It is interesting to note that, in the study of Kargman et al, five of six patients taking NSAIDs had low or undetectable COX-2 protein expression. 7 Moreover, aspirin has recently been shown to suppress induction of COX-2 mRNA and protein in interleukin-1 and phorbol ester stimulated human endothelial cells and fibroblasts. 8 Do the authors have data on NSAID use in their cohort of patients prior to surgery?

Gastroenterology, 2014

Intestinal villi provide an enormous surface area for nutrient absorption. Significant loss of in... more Intestinal villi provide an enormous surface area for nutrient absorption. Significant loss of intestinal surface area can compromise intestinal function, causing intestinal failure. Though short-term treatments for this life-threatening condition are available, all patients need lifelong monitoring for growth and nutritional status, and would benefit from treatments that can directly increase intestinal surface area. In mice, a large increase in surface area occurs with villus development, which begins at embryonic day (E)14.5, when the thick pseudostratified epithelium with a flat luminal surface is converted to a columnar epithelium covering a field of emerging villi. Though it has long been thought that epithelial remodeling occurs by formation and fusion of secondary lumina, recent work in our laboratory showed that secondary lumina do not exist (Grosse et al., Development 138:4423, 2011). Seeking an alternative mechanism for luminal expansion, we found a unique type of cell division that is triggered specifically at E14.5, which we have named an e-division (lumen extending division). We propose that in an e-division, new apical surface is deposited at the cytokinetic plane such that the two daughter cells segregate onto adjacent villi. The e-division is distinct from cell divisions occurring before E14.5, which we have named g-divisions (girth building divisions); g-divisions do not involve deposition of new apical surface between daughter cells. Our data (lineage tracing, 3D reconstruction, and SEM) suggest that in mice deficient in the apical surface protein Ezrin, e-divisions fail stochastically, resulting in fused villi. We are modeling e-divisions in vitro using MDCK and Caco2 cell lines, which form luminal surfaces during the first cell division when plated in a 3D matrix. Using RNA interference, we have found that reducing Ezrin expression compromises lumen formation in our 3D cyst assay, providing a mechanistic explanation for the presence of fused villi in vivo. Further understanding of the process of villus development will improve in vitro bioengineering of intestinal surface, potentially yielding novel therapies for those with intestinal failure.