Effect of Helicobacter pylori Eradication Therapy on the Incidence of Noncardia Gastric Adenocarcinoma in a Large Diverse Population in the United States.

BACKGROUND & AIMS: High-quality data regarding the effect of Helicobacter pylori eradication on the risk of noncardia gastric adenocarcinoma (NCGA) remain limited in the United States. We investigated the incidence of NCGA after H pylori eradication therapy in a large, community-based US population. METHODS: We performed a retrospective cohort study of Kaiser Permanente Northern California members who underwent testing and/or treatment for H pylori between 1997 and 2015 and were followed through December 31, 2018. The risk of NCGA was evaluated using the Fine-Gray subdistribution hazard model and standardized incidence ratios. RESULTS: Among 716,567 individuals with a history of H pylori testing and/or treatment, the adjusted subdistribution hazard ratios and 95% confidence intervals of NCGA for H pylori-positive/untreated and H pylori-positive/treated individuals were 6.07 (4.20-8.76) and 2.68 (1.86-3.86), respectively, compared with H pylori-negative individuals. When compared directly with H pylori-positive/untreated individuals, subdistribution hazard ratios for NCGA in H pylori-positive/treated were 0.95 (0.47-1.92) at <8 years and 0.37 (0.14-0.97) ≥8 years of follow-up. Compared with the Kaiser Permanente Northern California general population, standardized incidence ratios (95% confidence interval) of NCGA steadily decreased after H pylori treatment: 2.00 (1.79-2.24) ≥1 year, 1.01 (0.85-1.19) ≥4 years, 0.68 (0.54-0.85) ≥7 years, and 0.51 (0.38-0.68) ≥10 years. CONCLUSION: In a large, diverse, community-based population, H pylori eradication therapy was associated with a significantly reduced incidence of NCGA after 8 years compared with no treatment. The risk among treated individuals became lower than the general population after 7 to 10 years of follow-up. The findings support the potential for substantial gastric cancer prevention in the United States through H pylori eradication.

Risk stratification for colorectal cancer in individuals with subtypes of serrated polyps.

OBJECTIVE: The longitudinal risk of colorectal cancer (CRC) associated with subtypes of serrated polyps (SPs) remains incompletely understood. DESIGN: This community-based, case-control study included 317 178 Kaiser Permanente Northern California members who underwent their first colonoscopy during 2006-2016. Nested within this population, we identified 695 cases of CRC and 3475 CRC-free controls (matched 5:1 to cases for age, sex and year of colonoscopy). Two expert pathologists reviewed the tissue slides of all SPs identified on the first colonoscopy and reclassified them to sessile serrated lesions (SSLs), hyperplastic polyps (HPs) and traditional serrated adenomas. SPs with borderline characteristics of SSLs but insufficient to make a definitive diagnosis were categorised as unspecified SPs. The association with development of CRC was assessed using multivariable logistic regression. RESULTS: Compared with individuals with no polyp, the adjusted ORs (aORs) for SSL alone or with synchronous adenoma were 2.9 (95% CI: 1.8 to 4.8) and 4.4 (95% CI: 2.7 to 7.2), respectively. The aORs for SSL with dysplasia, large proximal SSL,and small proximal SSL were 10.3 (95% CI: 2.1 to 50.3), 12.8 (95% CI: 3.5 to 46.9) and 1.9 (95% CI: 0.8 to 4.7), respectively. Proximal unspecified SP also conferred an increased risk (aOR: 5.8, 95% CI: 2.2 to 15.2). Women with SSL were associated with higher risk (aOR: 4.4; 95% CI: 2.3 to 8.2) than men (aOR: 1.7; 95% CI: 0.8 to 3.8). CONCLUSION: Increased risk of CRC was observed in individuals with SSLs, particularly large proximal ones or with dysplasia, supporting close endoscopic surveillance. Proximal unspecified SPs were also associated with increased risk of CRC and should be managed as SSLs.

Comparison of Surgical and Cadaveric Intestine as a Source of Crypt Culture in Humans.

Human small intestinal crypts are the source of intestinal stem cells (ISCs) that are capable of undergoing self-renewal and differentiation to an epithelial layer. The development of methods to expand the ISCs has provided opportunities to model human intestinal epithelial disorders. Human crypt samples are usually obtained from either endoscopic or discarded surgical samples, and are thereby exposed to warm ischemia, which may impair their in vitro growth as three-dimensional culture as spheroids or enteroids. In this study we compared duodenal samples obtained from discarded surgical samples to those isolated from whole-body preserved cadaveric donors to generate in vitro cultures. We also examined the effect of storage solution (phosphate-buffered saline or University of Wisconsin [UW] solution) as well as multiple storage times on crypt isolation and growth in culture. We found that intestinal crypts were successfully isolated from cadaveric tissue stored for up to 144 h post-procurement and also were able to generate enteroids and spheroids in certain media conditions. Surgical samples stored in UW after procurement were sufficiently viable up to 24 h and also allowed the generation of enteroids and spheroids. We conclude that surgical samples stored for up to 24 h post-procurement in UW solution allowed for delayed crypt isolation and viable in vitro cultures. Furthermore, in situ, hypothermic preservation in cadaveric duodenal samples permitted crypt/ISC isolation, and successful culture of spheroids and enteroids from tissues held for up to 6 days post-procurement.

Bioengineering functional smooth muscle with spontaneous rhythmic contraction in vitro.

Oriented smooth muscle layers in the intestine contract rhythmically due to the action of interstitial cells of Cajal (ICC) that serve as pacemakers of the intestine. Disruption of ICC networks has been reported in various intestinal motility disorders, which limit the quality and expectancy of life. A significant challenge in intestinal smooth muscle engineering is the rapid loss of function in cultured ICC and smooth muscle cells (SMC). Here we demonstrate a novel approach to maintain the function of both ICC and SMC in vitro. Primary intestinal SMC mixtures cultured on feeder cells seeded electrospun poly(3-caprolactone) scaffolds exhibited rhythmic contractions with directionality for over 10 weeks in vitro. The simplicity of this system should allow for wide usage in research on intestinal motility disorders and tissue engineering, and may prove to be a versatile platform for generating other types of functional SMC in vitro.

A novel culture system for adult porcine intestinal crypts.

Porcine models are useful for investigating therapeutic approaches to short bowel syndrome and potentially to intestinal stem cell (ISC) transplantation. Whereas techniques for the culture and genetic manipulation of ISCs from mice and humans are well established, similar methods for porcine stem cells have not been reported. Jejunal crypts were isolated from murine, human, and juvenile and adult porcine small intestine, suspended in Matrigel, and co-cultured with syngeneic intestinal subepithelial myofibroblasts (ISEMFs) or cultured without feeder cells in various culture media. Media containing epidermal growth factor, noggin, and R-spondin 1 (ENR medium) were supplemented with various combinations of Wnt3a- or ISEMF-conditioned medium (CM) and with glycogen synthase kinase 3 inhibitor (GSK3i), and their effects were studied on cultured crypts. Cell lineage differentiation was assessed by immunohistochemistry and quantitative polymerase chain reaction. Cultured porcine cells were serially passaged and transduced with a lentiviral vector. Whereas ENR medium supported murine enteroid growth, it did not sustain porcine crypts beyond 5 days. Supplementation of Wnt3a-CM and GSK3i resulted in the formation of complex porcine enteroids with budding extensions. These enteroids contained a mixture of stem and differentiated cells and were successfully passaged in the presence of GSK3i. Crypts grown in media supplemented with porcine ISEMF-CM formed spheroids that were less well differentiated than enteroids. Enteroids and spheroids were transfected with a lentivirus with high efficiency. Thus, our method maintains juvenile and adult porcine crypt cells long-term in culture. Porcine enteroids and spheroids can be successfully passaged and transduced by using lentiviral vectors.

Development of Functional Microfold (M) Cells from Intestinal Stem Cells in Primary Human Enteroids.

BACKGROUND & AIMS: Intestinal microfold (M) cells are specialized epithelial cells that act as gatekeepers of luminal antigens in the intestinal tract. They play a critical role in the intestinal mucosal immune response through transport of viruses, bacteria and other particles and antigens across the epithelium to immune cells within Peyer's patch regions and other mucosal sites. Recent studies in mice have demonstrated that M cells are generated from Lgr5+ intestinal stem cells (ISCs), and that infection with Salmonella enterica serovar Typhimurium increases M cell formation. However, it is not known whether and how these findings apply to primary human small intestinal epithelium propagated in an in vitro setting. METHODS: Human intestinal crypts were grown as monolayers with growth factors and treated with recombinant RANKL, and assessed for mRNA transcripts, immunofluorescence and uptake of microparticles and S. Typhimurium. RESULTS: Functional M cells were generated by short-term culture of freshly isolated human intestinal crypts in a dose- and time-dependent fashion. RANKL stimulation of the monolayer cultures caused dramatic induction of the M cell-specific markers, SPIB, and Glycoprotein-2 (GP2) in a process primed by canonical WNT signaling. Confocal microscopy demonstrated a pseudopod phenotype of GP2-positive M cells that preferentially take up microparticles. Furthermore, infection of the M cell-enriched cultures with the M cell-tropic enteric pathogen, S. Typhimurium, led to preferential association of the bacteria with M cells, particularly at lower inoculum sizes. Larger inocula caused rapid induction of M cells. CONCLUSIONS: Human intestinal crypts containing ISCs can be cultured and differentiate into an epithelial layer with functional M cells with characteristic morphological and functional properties. This study is the first to demonstrate that M cells can be induced to form from primary human intestinal epithelium, and that S. Typhimurium preferentially infect these cells in an in vitro setting. We anticipate that this model can be used to generate large numbers of M cells for further functional studies of these key cells of intestinal immune induction and their impact on controlling enteric pathogens and the intestinal microbiome.

Primary Myofibroblasts Maintain Short-Term Viability following Submucosal Injection in Syngeneic, Immune-Competent Mice Utilizing Murine Colonoscopy.

The myofibroblast is an important stromal cell of the gastrointestinal tract. Current in vitro and in vivo models either do not accurately recreate stromal-epithelial interactions or are not specific to myofibroblasts. We sought to create an animal model that would allow the study of myofibroblast-epithelial interactions. We isolated and cultured colonic myofibroblasts from FVB mice. Cells were α-SMA and vimentin positive but desmin negative on immunoblot analysis. We injected the myofibroblasts into the colonic submucosa of syngeneic adult mice (n = 8) via a miniendoscopic system. We then isolated green fluorescent protein (GFP) positive colonic myofibroblasts from C57BL/6-Tg(CAG-EGFP)1Osb/J mice and injected them into the colonic lamina propria of C57BL/6J mice at 1x10(5) (n = 14), 1x10(6) (n = 9), or 5x10(6) cells/mL (n = 4). A subset of mice were injected with serum-free media and ink without cells (n = 3). Mice underwent repeat endoscopy and euthanasia one or 7 days after injection. Colons were isolated and either fixed in 10% formalin or the inked sites were individually excised and lysed for DNA. We assessed the injection sites via histology and immunohistochemical stains for α-SMA and GFP. We used qPCR to quantify GFP DNA transcripts at the lamina propria injection sites. Submucosal injection of myofibroblasts resulted in the formation of a subepithelial wheal on endoscopy, which persisted to day 7. Myofibroblasts injected either into the submucosa or lamina propria maintained viability on post-injection day 7 as evidenced by positive α-SMA staining. qPCR of lamina propria injections showed a dose-dependent increase in GFP DNA transcripts on post-injection day 1, whereas the number of transcripts on day 7 was equivalent for the concentrations injected. We demonstrate short-term survival of primary cultured colonic myofibroblasts in syngeneic mice. This may prove to be a valuable model for studying the role of myofibroblasts in states of health and disease.

Isolation and characterization of intestinal stem cells based on surface marker combinations and colony-formation assay.

BACKGROUND & AIMS: Identification of intestinal stem cells (ISCs) has relied heavily on the use of transgenic reporters in mice, but this approach is limited by mosaic expression patterns and difficult to directly apply to human tissues. We sought to identify reliable surface markers of ISCs and establish a robust functional assay to characterize ISCs from mouse and human tissues. METHODS: We used immunohistochemistry, real-time reverse-transcription polymerase chain reaction, and fluorescence-activated cell sorting (FACS) to analyze intestinal epithelial cells isolated from mouse and human intestinal tissues. We compared different combinations of surface markers among ISCs isolated based on expression of Lgr5-green fluorescent protein. We developed a culture protocol to facilitate the identification of functional ISCs from mice and then tested the assay with human intestinal crypts and putative ISCs. RESULTS: CD44(+)CD24(lo)CD166(+) cells, isolated by FACS from mouse small intestine and colon, expressed high levels of stem cell-associated genes. Transit-amplifying cells and progenitor cells were then excluded based on expression of GRP78 or c-Kit. CD44(+)CD24(lo)CD166(+) GRP78(lo/-) putative stem cells from mouse small intestine included Lgr5-GFP(hi) and Lgr5-GFP(med/lo) cells. Incubation of these cells with the GSK inhibitor CHIR99021 and the E-cadherin stabilizer Thiazovivin resulted in colony formation by 25% to 30% of single-sorted ISCs. CONCLUSIONS: We developed a culture protocol to identify putative ISCs from mouse and human tissues based on cell surface markers. CD44(+)CD24(lo)CD166(+), GRP78(lo/-), and c-Kit(-) facilitated identification of putative stem cells from the mouse small intestine and colon, respectively. CD44(+)CD24(-/lo)CD166(+) also identified putative human ISCs. These findings will facilitate functional studies of mouse and human ISCs.

Use of collagen gel as an alternative extracellular matrix for the in vitro and in vivo growth of murine small intestinal epithelium.

Methods for the in vitro culture of primary small intestinal epithelium have improved greatly in recent years. A critical barrier for the translation of this methodology to the patient's bedside is the ability to grow intestinal stem cells using a well-defined extracellular matrix. Current methods rely on the use of Matrigel(™), a proprietary basement membrane-enriched extracellular matrix gel produced in mice that is not approved for clinical use. We demonstrate for the first time the capacity to support the long-term in vitro growth of murine intestinal epithelium in monoculture, using type I collagen. We further demonstrate successful in vivo engraftment of enteroids co-cultured with intestinal subepithelial myofibroblasts in collagen gel. Small intestinal crypts were isolated from 6 to 10 week old transgenic enhanced green fluorescent protein (eGFP+) mice and suspended within either Matrigel or collagen gel; cultures were supported using previously reported media and growth factors. After 1 week, cultures were either lysed for DNA or RNA extraction or were implanted subcutaneously in syngeneic host mice. Quantitative real-time polymerase chain reaction (qPCR) was performed to determine expansion of the transgenic eGFP-DNA and to determine the mRNA gene expression profile. Immunohistochemistry was performed on in vitro cultures and recovered in vivo explants. Small intestinal crypts reliably expanded to form enteroids in either Matrigel or collagen in both mono- and co-cultures as confirmed by microscopy and eGFP-DNA qPCR quantification. Collagen-based cultures yielded a distinct morphology with smooth enteroids and epithelial monolayer growth at the gel surface; both enteroid and monolayer cells demonstrated reactivity to Cdx2, E-cadherin, CD10, Periodic Acid-Schiff, and lysozyme. Collagen-based enteroids were successfully subcultured in vitro, whereas pure monolayer epithelial sheets did not survive passaging. Reverse transcriptase-polymerase chain reaction demonstrated evidence of Cdx2, villin 1, mucin 2, chromogranin A, lysozyme 1, and Lgr5 expression, suggesting a fully elaborated intestinal epithelium. Additionally, collagen-based enteroids co-cultured with myofibroblasts were successfully recovered after 5 weeks of in vivo implantation, with a preserved immunophenotype. These results indicate that collagen-based techniques have the capacity to eliminate the need for Matrigel in intestinal stem cell culture. This is a critical step towards producing neo-mucosa using good manufacturing practices for clinical applications in the future.

Intestinal subepithelial myofibroblasts support in vitro and in vivo growth of human small intestinal epithelium.

The intestinal crypt-niche interaction is thought to be essential to the function, maintenance, and proliferation of progenitor stem cells found at the bases of intestinal crypts. These stem cells are constantly renewing the intestinal epithelium by sending differentiated cells from the base of the crypts of Lieberkühn to the villus tips where they slough off into the intestinal lumen. The intestinal niche consists of various cell types, extracellular matrix, and growth factors and surrounds the intestinal progenitor cells. There have recently been advances in the understanding of the interactions that regulate the behavior of the intestinal epithelium and there is great interest in methods for isolating and expanding viable intestinal epithelium. However, there is no method to maintain primary human small intestinal epithelium in culture over a prolonged period of time. Similarly no method has been published that describes isolation and support of human intestinal epithelium in an in vivo model. We describe a technique to isolate and maintain human small intestinal epithelium in vitro from surgical specimens. We also describe a novel method to maintain human intestinal epithelium subcutaneously in a mouse model for a prolonged period of time. Our methods require various growth factors and the intimate interaction between intestinal sub-epithelial myofibroblasts (ISEMFs) and the intestinal epithelial cells to support the epithelial in vitro and in vivo growth. Absence of these myofibroblasts precluded successful maintenance of epithelial cell formation and proliferation beyond just a few days, even in the presence of supportive growth factors. We believe that the methods described here can be used to explore the molecular basis of human intestinal stem cell support, maintenance, and growth.

Controlled release of vascular endothelial growth factor enhances intestinal adaptation in rats with extensive small intestinal resection.

BACKGROUND: Vascular endothelial growth factor (VEGF) has been shown to be an essential factor in the intestinal adaption after extensive bowel resection. The present study investigates the controlled release of VEGF as a way to improve intestinal adaptation. MATERIALS AND METHODS: Biodegradable microspheres with or without VEGF were made using a double emulsion technique. Approximately 80% of the small intestine was removed, leaving the entire duodenum, 10 cm of jejunum, and 7 cm of ileum. The microspheres were distributed on the anastomosed small bowel. The animals were sacrificed after 14 days, and the adapted jejunum and ileum were analyzed for sucrase activity and histologic parameters. RESULTS: The average villus lengths of the adapted jejunum and ileum were 680 and 350 µm in rats that received blank microspheres, compared to 810 and 720 µm in rats that received VEGF microspheres. The average sucrase activity of the adapted jejunum and ileum was 0.0202 and 0.0073 µmol/mg protein/min in rats that received blank microspheres, compared with 0.0236 and 0.0232 µmmol/mg protein/min in rats that received VEGF microspheres. CONCLUSION: The data suggest that the controlled delivery of VEGF from microspheres enhances the adaptation of the small intestine in rats. The controlled delivery of VEGF over time can potentially be used in patients following extensive intestinal resection.