Small Bowel Crypt Research Articles

Correlation between intestinal stem cell niche changes and small bowel crypt failure in patients with treatment-naïve celiac disease.

We hypothesized that crypt failure in the small bowel results in villous flattening in patients with celiac disease (CeD). We investigated whether alterations in the stem cell niche (ISC) are responsible for this phenomenon. We included 92 duodenal (D2/3) biopsies from treatment-naive patients of CeD and 37 controls. All underwent screening for serum anti-tissue transglutaminase and endoscopic upper small bowel biopsy. Immunohistochemical markers were used to investigate ISC niche alterations, including LGR5 for crypt basal cells (CBC), Bmi1 for position 4+ cells, β-Defensin for Paneth cells, R-spondin1 as WNT activator, transcription factor-4 as WNT transcription factor, BMP receptor1A as WNT inhibitor, fibronectin-1 as periepithelial stromal cell marker, H2AX as apoptosis marker, and Ki67 as proliferation marker. We also analyzed IgA anti-tTG2 antibody deposits by using dual-color immunofluorescence staining. We found that in biopsies from patients with treatment-naive CeD with modified Marsh grade 3a-3c changes, the epithelial H2AX apoptotic index was upregulated than in controls. LGR5+ crypt basal cells were upregulated in all modified Marsh grades compared to controls. However, the Ki67 proliferation index, expressions of WNT-activator RSPO1, and position-4 cell marker Bmi1 did not significantly alter in patients' biopsies as compared to controls ( P = 0.001). We also observed depletion of pericrypt stromal fibronectin-1 in patients with CeD compared to controls. In addition, we identified IgA anti-TG2 antibody deposits in pericrypt stroma. Our data suggests that ISC niche failure is a plausible hypothesis for villous flattening in patients with CeD, resulting from pericrypt IgA anti-TG2 antibody complex-mediated stromal depletion.

In vivo gene expression profiling of human intestinal epithelial cells: analysis by laser microdissection of formalin fixed tissues

BackgroundThe small intestinal epithelium mediates vital functions of nutrient absorption and host defense. The spatial organization of the epithelial cells along the crypt-villus axis segregates them into regions of specialized function. However, the differences in transcriptional programming and the molecular machinery that governs the migration, adhesion, and differentiation of intestinal epithelial cell lineages in humans remain under-explored. To increase our understanding of these mechanisms, we have evaluated gene expression patterns of ileal epithelial cells isolated by laser capture microdissection from either the villus epithelial or crypt cell regions of healthy human small intestinal mucosa. Expression profiles in villus and crypt epithelium were determined by DNA microarray, quantitative real-time PCR, and immunohistochemistry based methods. The expression levels of selected epithelial biomarkers were also compared between gastrointestinal tissues.ResultsPreviously established biomarkers as well as a novel and distinct set of genes believed to be linked to epithelial cell motility, adhesion, and differentiation were found to be enriched in each of the two corresponding cell populations (GEO accession: GSE10629). Additionally, high baseline expression levels of innate antimicrobials, alpha defensin 5 (HD5) and regenerating islet-derived 3 alpha (Reg3A), were detected exclusively within the small bowel crypt, most notably in the ileum in comparison to other sites along the gastrointestinal tract.ConclusionThe elucidation of differential gene expression patterns between crypt and villus epithelial cell lineages in human ileal tissue provides novel insights into the molecular machinery that mediates their functions and spatial organization. Moreover, our findings establish an important framework of knowledge for future investigations of human gastrointestinal diseases.

CEACAM-1 Is Involved in Graft-Versus-Host-Disease in Murine Allogeneic Bone Marrow Transplantation Models.

Carcinoembryonic antigen associated cell adhesion molecule 1 (CEACAM-1) belongs to a family of carcinoembryonic antigen-associated glycoproteins. It is expressed on leukocytes, endothelium, and epithelium. Microarray analysis showed that CEACAM-1 mRNA is increased in the small bowel during gut graft-versus-host-disease (GVHD) after allogeneic bone marrow transplantation (allo-BMT). Using CEACAM-1−/− mice as recipients or sources of donor bone marrow or T cells caused significantly worse GVHD mortality (p<0.05) compared to wildtype (WT) controls. Histopathological analysis of GVHD target organs from CEACAM-1−/− recipients of WT T cells or WT recipients of CEACAM-1−/− T cells revealed increased GVHD of the large bowel (p<0.05) but not liver or small bowel compared to WT control. Alloreactive splenic CD8 CEACAM-1−/− T cells from recipients with GVHD had increased levels of α4β7 integrin compared to WT controls. We also found increased numbers of small bowel intraepithelial lymphocytes and mesenteric lymph node cellularity in CEACAM-1−/− recipients of WT T cells and WT recipients of CEACAM-1−/− T cells, with a corresponding decrease of cellularity in peripheral lymph nodes and the liver. Adoptive transfer of CFSEhi CEACAM-1−/− T cells into WT hosts, or of WT T cells into CEACAM 1−/− hosts revealed more profound activation of T cells in CEACAM-1 deficient settings, shown by increased early CD25 expression and CD62L down-regulation on splenic CFSEdim alloreactive T cells. We found no significant differences in serum levels of TNF or IFNγ, T cell proliferation kinetics upon adoptive transfer, percentages of alloactivated CD4 or CD8 cells, intracellular levels of T-bet or IFNγ, CD8 T cell cytolytic efficiency, percentages of splenic regulatory T cells, or levels of T cell apoptosis in WT recipients of CEACAM-1−/− T cells or CEACAM-1−/− recipients of WT T cells with GVHD as compared with controls. Finally, irradiation of non-transplanted CEACAM-1−/− mice revealed increased radiation sensitivity, shown by earlier and greater lethality and increased small bowel crypt apoptosis, suggesting a role for CEACAM-1 in conditioning-related toxicity and subsequent GVHD amplification. We conclude that CEACAM-1 deficiency on donor T cells or transplant recipients results in increased gut and systemic GVHD due to increased T cell activation and elevated expression of the gut homing integrin α4β7. This suggests that the use of CEACAM-1 agonists could be a novel theraputic strategy for ameliorating acute intestinal and systemic graft-versus-host-disease.

The long-term effect of pinealectomy on the crypts of the rat gastrointestinal tract.

Previously it has been found that rat small bowel crypt cell hyperplasia occurred several weeks after pinealectomy. To determine if this effect was longer-lasting (because of the possible role of the pineal in bowel malignancy) the crypt cell proliferation rate was determined in rat small bowel and colon 6 months after pinealectomy, using a stathmokinetic technique. Although the hyperproliferative effect of pinealectomy was well maintained in the small bowel crypts after 6 months, the hyperproliferative effect in the colonic crypts was much less marked. There is no obvious explanation for these findings, although it is possible that regional differences in levels of gut neuropeptides or melatonin are involved. The mechanism of the effect of pinealectomy on the crypts remains unexplained--in particular, why the effect is so prolonged.

Variation in the Enteric Distribution of Cryptosporidia in Acquired Immunodeficiency Syndrome

Clinical observation suggests that the natural history of intestinal cryptosporidiosis in patients with acquired immunodeficiency syndrome varies greatly. The relation between clinical, small-bowel functional, and nutritional status and the intestinal distribution of the organism was studied in 41 patients who had acquired immunodeficiency syndrome and cryptosporidiosis and who had undergone both proximal small-bowel and colonic biopsies. Two patterns of enteric cryptosporidiosis were identified: severe clinical disease with malabsorption in patients with cryptosporidia in proximal small-bowel biopsy specimens (61% of cases) and less severe clinical disease in patients with cryptosporidia only in the colon or stool (39% of cases). Patients with cryptosporidia in proximal small-bowel biopsy specimens had small-bowel crypt hyperplastic villous atrophy, lamina propria inflammatory infiltrates, poorer D-xylose absorption, greater weight loss, and shorter survival and more often needed intravenous hydration or hyperalimentation. Patients with cryptosporidia in the small-bowel villi only had less severe disease than those with cryptosporidia in the small-bowel crypts. In conclusion, the anatomic distribution of intestinal cryptosporidia in patients with acquired immunodeficiency syndrome varies, and this variation may explain differences in clinical course. Cryptosporidial infection of the proximal small bowel correlates with mucosal injury, malabsorption, dehydration, weight loss, and shortened survival.

The effect of pinealectomy and autonomic denervation on crypt cell proliferation in the rat small intestine

Previously it has been found that pinealectomy in rats was associated with increased small bowel crypt cell proliferation. The hypothalamus is thought to play a role in the neural control of crypt cell proliferation and the pineal gland is known to be functionally connected with this component of the autonomic nervous system. Consequently, the effect on crypt cell mitotic rate of pinealectomy with autonomic denervation of the rat small bowel (local sympathectomy and truncal vagotomy) was observed to determine the possible importance of the autonomic nervous system in the mediation of the effects of pinealectomy on the crypts. It was found that interruption of either the vagal or sympathetic nerve supply to the small intestine both significantly decreased the usual hyperproliferative effect on the crypt cells observed after pinealectomy. It is suggested that the overall effect of the pineal gland is to suppress the crypt cell proliferation rate and that this effect is mediated, at least to some extent, by (1) the direct connections between the pineal gland and the hypothalamus, (2) the connections between the hypothalamus and the vagal and sympathetic innervation of the gut, and (3) the influence of the autonomic innervation on the activity of the enteric plexuses in relationship to the crypts. The pineal may have a role in modulating the local control mechanism of crypt cell proliferation. Its exact role in the control of crypt cell proliferation has not yet been defined.

Effect of Septal and Fornix Lesions on Rat Small Bowel Crypt Cell Kinetics

The septum and fornix are known to modulate the functional activity of the hypothalamus. Since the hypothalamus has been shown to influence crypt cell mitotic rate, it was considered possible that the septum and fornix might have a similar influence. Using a stathmokinetic technique, bilateral fornix and septal lesions were found to be associated with a marked increase in rat small bowel crypt cell mitotic rate. There was no associated significant change in food intake. It appears possible that the effects of the septal and fornix lesions may have been mediated via their influence over the functions of the hypothalamus.

The effect of bilateral amygdaloid nucleus lesions on rat small bowel crypt cell kinetics

Previous investigators have found that central nervous system lesions, in particular lesions of the hypothalamus, may increase the crypt cell mitotic rate in the rat small bowel. Since the amygdaloid nuclei form part of the limbic system (the "visceral brain") and have functional neural connections with the hypothalamus the effect of bilateral electrocoagulation lesions of the amygdaloid nuclei on crypt cell mitotic rate in the rat small bowel was investigated, using a stathmokinetic technique. Bilateral amygdaloid lesions were found to be associated with a marked increase in crypt cell mitotic rate in the proximal jejunum and distal ileum. Consideration of the neural connections of the amygdaloid nuclei suggests that these effects may possibly be mediated via the hypothalamus and the autonomic nervous system. The effects of lesions of other parts of the limbic system on crypt cell mitotic rate will be published subsequently.

The effect of pinealectomy and jejunal loop diversion on rat small bowel crypt cell kinetics

Previously, it was found that diversion of an isolated loop of jejunum into the colon was associated with a significantly diminished crypt cell proliferation rate in the isolated loop, probably principally because of the diminished amount of nutrient available to the diverted mucosa. It has also been shown previously that removal of the pineal gland is associated with a considerable increase in the jejunal crypt cell mitotic rate. In the present investigation it was found that following pinealectomy, whilst the rise in crypt cell proliferation elsewhere in the rat small intestine was maintained at the expected level, the mitotic rate in the crypts of an isolated jejunal loop attached to the colon was also increased to a similar level, despite the fact that this isolated loop was in contact with a considerably diminished level of luminal nutrients. Thus, the expected hypoproliferative effects of jejunal isolation were overridden by the hyperproliferative effects of pinealectomy and the effects of pinealectomy appeared to be independent of the particular changes in luminal environment produced in this experiment. The significance of these findings is discussed in the light of the available literature.