Human lens cells have an in vitro proliferative capacity inversely proportional to the donor age

Human epithelial lens cells (HEL) from embryos and 40–89-year-old donors were studied in vitro to evaluate their role in the maintenance and aging of the lens. Cells from young and old donors were cultured in MEM 199 with 15% fetal calf serum (FCS). While, like many other normal human epithelial cells, HEL cells have a low population doubling capacity, several of their properties could be studied. As a function of age a huge enlargement of the cytoplasm was observed. Cell surfaces of 60-year-old donors were on the average 3 times or more larger than embryo cells. With serial passages, they kept enlarging with accumulation in the cytoplasm of large vacuoles and bundles of filaments. Nuclei polyploidisation and fragmentation were frequent. Determination of the labelling index of these cells after the first subculture showed a clearly progressive age-related decline of their growth capacity. These results suggest an intrinsic progressive aging of this pure population of differentiated cells.     

Nuclear heterogeneity and proliferative capacity of human adipose derived MSC-like cells

Adipose derived stem cells (ADSCs) are MSC-like cells which could be easily used for regenerative medicine. Here, the morphology and proliferative capacity of human ADSCs is discribed. ADSCs were analyzed after one month of cultivation at a density of 10 cells/cm2. 21 colonies were counted. Few atypical cells (huge nuclei and cytoplasm) were found in 9 out of 17 colonies analyzed. ANOVA demonstrated that colonies also differed (P = 0.0025) in nuclei dimensions and scatter in the dimensions in each colony. Nuclei dimensions and cell density logarithms correlated in reverse proportion (-0.7; P = 0.002). Thus, ADSCs were heterogeneous and represented two types of cells: small highly proliferative and large low proliferative cells. Cell heterogeneity observed in some colonies might be due to cells registered at different cell cycle phases. Stable and typical morphology, colony-formation capability and high proliferative capacity of cells indicate visceral adipose tissue as a rich source of ADSCs.     

Mechanical properties of the human gastrointestinal tract

The tensile properties of the human esophagus, stomach, small and large bowel were examined on an Instron 1221 tensiometer. The values of maximal stress and destructive strain were the following: for esophagus-1.2 MPa and 140%, respectively, for stomach axial specimens-0.7 MPa and 190%, for stomach transversal specimens-0.5 MPa and 190%, for small bowel transversal specimens-0.9 MPa and 140% and for large bowel transversal specimens-0.9 MPa and 180%. Tests conducted on small and large bowel axial specimens permitted examination of the intestinal wall as a multi-layered structure. The mechanical properties of tested bowels in axial and transversal directions were qualitatively different. The submucosa and muscular layers condition the mechanical strength of bowel wall, while the serosa and mucosa showed no significant strength. Reproducible results were generated for cadaveric and surgically removed stomach and small intestine, which showed their mechanical properties similar under certain storage conditions. The data received could be used for monitoring of the mechanical properties of bowel wall layers under different conditions and for checking of bowel distension sequences.     

Damaged epithelia regenerated by bone marrow-derived cells in the human gastrointestinal tract

Studies have shown that bone marrow cells have the potential to differentiate into a variety of cell types. Here we show that bone marrow cells can repopulate the epithelia of the human gastrointestinal tract. Epithelial cells of male donor origin were distributed in every part of the gastrointestinal tract of female bone marrow transplant recipients. Donor-derived epithelial cells substantially repopulated the gastrointestinal tract during epithelial regeneration after graft-versus-host disease or ulcer formation. Regeneration of gastrointestinal epithelia with donor-derived cells in humans shows a potential clinical application of bone marrow-derived cells for repairing severely damaged epithelia, not only in the gastrointestinal tract but also in other tissues.     

Bacterial biofilms in the human gastrointestinal tract

Microbial biofilms were first described in 1936 and subsequent research has unveiled their ubiquity and physiological distinction from free-living (planktonic) microorganisms. In light of their emerging significance this review examines the bacterial biofilms within the human gastrointestinal tract. Attention is paid to the nature of these mucosally- associated populations, focusing on the protected environment afforded by the continual secretion of mucus by host epithelial cells. It also examines the attributes possessed by various bacterial species that facilitate habitation of this microenvironment. Additionally, contrasts are drawn between planktonic bacteria of the lumen and sessile (biofilm) bacteria growing in close association with host cells and food particles. In particular the different fermentation profiles exhibited by these two fractions are discussed. The potential role of these communities in host health and disease, as well as the stabilisation of the lumenal population, is also considered. Reference is made to the state of mutualism that exists between these little understood populations and the host epithelia, thus highlighting their ecological significance in terms of gastrointestinal health.     

Microbial biofilms in the human gastrointestinal tract

The human gastrointestinal tract contains rich and diverse microbiotas along its length. However, while extensive studies have been made on lumenal bacterial communities in the gut, less work has been carried out on organisms growing in biofilms, where individual groups of bacteria exist in a multiplicity of different microhabitats and metabolic niches associated with the mucosa, the mucus layer and particulate surfaces in the gut lumen. Bacteria and yeasts also occur in biofilms attached to artificial surfaces and devices implanted in the host, such as in patients being fed via enteral tubes. Although we are just beginning to investigate the composition and metabolic activities of these structures, increasing evidence suggests that they are important to the host in both health and disease. There is mounting interest in mucosal biofilms in the colon, especially with respect to their role in inflammatory bowel disease. Because bacteria growing in biofilms are more resistant to antibiotics than unattached organisms, it is often difficult to modify the structure and composition of these communities, or to eradicate them from the body. However, recent work has shown that there is considerable potential to alter the species composition of mucosal biofilms in a beneficial way using synbiotics.     

Interstitial cells in the primate gastrointestinal tract

Kit immunohistochemistry and confocal reconstructions have provided detailed 3-dimensional images of ICC networks throughout the gastrointestinal (GI) tract. Morphological criteria have been used to establish that different classes of ICC exist within the GI tract and physiological studies have shown that these classes have distinct physiological roles in GI motility. Structural studies have focused predominately on rodent models and less information is available on whether similar classes of ICC exist within the GI tracts of humans or non-human primates. Using Kit immunohistochemistry and confocal imaging, we examined the 3-dimensional structure of ICC throughout the GI tract of cynomolgus monkeys. Whole or flat mounts and cryostat sections were used to examine ICC networks in the lower esophageal sphincter (LES), stomach, small intestine and colon. Anti-histamine antibodies were used to distinguish ICC from mast cells in the lamina propria. Kit labeling identified complex networks of ICC populations throughout the non-human primate GI tract that have structural characteristics similar to that described for ICC populations in rodent models. ICC-MY formed anastomosing networks in the myenteric plexus region. ICC-IM were interposed between smooth muscle cells in the stomach and colon and were concentrated within the deep muscular plexus (ICC-DMP) of the intestine. ICC-SEP were found in septal regions of the antrum that separated circular muscle bundles. Spindle-shaped histamine⁺ mast cells were found in the lamina propria throughout the GI tract. Since similar sub-populations of ICC exist within the GI tract of primates and rodents and the use of rodents to study the functional roles of different classes of ICC is warranted.     

Endocrine cells of the human gastric mucosa

Summary By light and electron microscopy investigation of the human gastric mucosa five types of ultrastructurally different endocrine cells have been detected: 5-hydroxytryptamine storing enterochromaffin (EC) cells, gastrin storing G cells, and functionally undefined ECL, D and D₁ cells. By direct application of Masson's argentaffin reaction as well as of Sevier-Munger's and Grimelius' argyrophil method to electron microscopy specimens, selective deposition of silver grains upon the endocrine granules of such cells was obtained. In particular, only EC cell granules reacted to the argentaffin method, granules of both EC and ECL cells heavily reacted to Sevier-Munger's technique, granules of EC, ECL, G and D₁ cells reacted to Grimelius' technique, while D cell granules failed to react either to argentaffin or argyrophil methods. By the application of the same silver methods to paraffin sections as well as by other selective staining methods for endocrine granules (5-hydroxytryptamine techniques, lead-haematoxylin, HCl-basic dye method), at least four of the above cell types were also identified under light microscope. This opens the way for extensive studies of such cells in conventional histologie specimens.This investigation was supported in part by grant N.70.01022.04 from the Italian Consiglio Nazionale delle Ricerche.     

Biomarkers of human gastrointestinal tract regions

Dysregulation of intestinal epithelial cell performance is associated with an array of pathologies whose onset mechanisms are incompletely understood. While whole-genomics approaches have been valuable for studying the molecular basis of several intestinal diseases, a thorough analysis of gene expression along the healthy gastrointestinal tract is still lacking. The aim of this study was to map gene expression in gastrointestinal regions of healthy human adults and to implement a procedure for microarray data analysis that would allow its use as a reference when screening for pathological deviations. We analyzed the gene expression signature of antrum, duodenum, jejunum, ileum, and transverse colon biopsies using a biostatistical method based on a multivariate and univariate approach to identify region-selective genes. One hundred sixty-six genes were found responsible for distinguishing the five regions considered. Nineteen had never been described in the GI tract, including a semaphorin probably implicated in pathogen invasion and six novel genes. Moreover, by crossing these genes with those retrieved from an existing data set of gene expression in the intestine of ulcerative colitis and Crohn’s disease patients, we identified genes that might be biomarkers of Crohn’s and/or ulcerative colitis in ileum and/or colon. These include CLCA4 and SLC26A2, both implicated in ion transport. This study furnishes the first map of gene expression along the healthy human gastrointestinal tract. Furthermore, the approach implemented here, and validated by retrieving known gene profiles, allowed the identification of promising new leads in both healthy and disease states.     

Diversity of the human gastrointestinal tract microbiota revisited

Since the early days of microbiology, more than a century ago, representatives of over 400 different microbial species have been isolated and fully characterized from human gastrointestinal samples. However, during the past decade molecular ecological studies based on ribosomal RNA (rRNA) sequences have revealed that cultivation has been able only to access a small fraction of the microbial diversity within the gastrointestinal tract. The increasing number of deposited rRNA sequences calls for the setting up a curated database that allows handling of the excessive degree of redundancy that threatens the usability of public databases. The integration of data from cultivation-based studies and molecular inventories of small subunit (SSU) rRNA diversity, presented here for the first time, provides a systematic framework of the microbial diversity in the human gastrointestinal tract of more than 1000 different species-level phylogenetic types (phylotypes). Such knowledge is essential for the design of high-throughput approaches such as phylogenetic DNA microarrays for the comprehensive analysis of gastrointestinal tract microbiota at multiple levels of taxonomic resolution. Development of such approaches is likely to be pivotal to generating novel insights in microbiota functionality in health and disease.     

Activity of phenolsulfotransferases in the human gastrointestinal tract

Sulfate conjugation by sulfotransferase enzymes is an important pathway for the detoxication of xenobiotics and endogenous compounds. The large surface area of the gastrointestinal tract exposes the body to a range of potential toxins, and hence local metabolism is likely to be important. The ability of different regions of the gut to sulfate micromolar concentrations of simple phenols and catecholamines has been determined throughout the gut using 4-nitrophenol and dopamine as standard substrates. The pattern of sulfation of both compounds was similar, with activity highest in the small bowel >right colon >left colon >rectum >stomach >esophagus. High concentrations of sulfotransferases in the reservoir areas of the right and left colon indicate possible importance in detoxication by sulfation and also perhaps in activating mutagens in the same areas. Nutritional factors, such as a high-fat diet may, however, alter sulfotransferase activity.     

Immunocytochemical identification of polypeptide YY (PYY) cells in the human gastrointestinal tract

Various parts of the human gastrointestinal tract were investigated immunocytochemically for the occurrence of polypeptide YY (PYY) and pancreatic polypeptide (PP). PYY-immunoreactive cells were observed in the lower part of the ileum, in the colon and in the rectum, and PP-immunoreactive cells were found in the colon and rectum. Both cell types were of the open type, i.e. they extended from the basal lamina to the gut lumen. PYY-immunoreactive cells were seen to emit cytoplasmic processes to the neighbouring goblet cells. This latter observation suggests that PYY cells may exert a paracrine action on the mucus-secreting goblet cells. Staining of consecutive thin plastic sections and staining of the same section simultaneously for two peptides showed that PYY-immunoreactivity did not occur in PP- or enteroglucagon-immunoreactive cells. On the ultrastructural level PYY-immunoreactivity was localized in basal granulated endocrine cells. These cells contained round or slightly oval electron dense granules with a mean diameter of 150 nm (range 100-300 nm).     

Bombesin-like immunoreactivity in human gastrointestinal tract

In the present study the distribution and molecular characteristics of bombesin-like immunoreactivity (BLI) were studied in acid extracts of human gastrointestinal tract. The highest levels were found in the fundus, antrum, pylorus and pancreas with lower levels in the duodenum, jejunum, terminal ileum and colon. BLI was also detected in both the muscle and mucosal layers of the antrum and colon. Sephadex G-50 gel chromatography under acid dissociating conditions revealed two peaks of immunoreactivity, one in the position of synthetic porcine gastrin releasing peptide (GRP) and the second eluting with synthetic amphibian bombesin. Variations in the proportions of the two molecular forms were seen in different regions of the gut. In the stomach and pancreas greater than 70% of the BLI eluted with the GRP marker while in pylorus, jejunum and terminal ileum only 20% was present in this form. Reverse-phase ODS silica HPLC of the major antral BLI peak, utilising a methanol/trifluoroacetic acid gradient indicated that this peptide was similar to porcine GRP. We have therefore (1) demonstrated the presence and heterogeneity of bombesin-like immunoreactivity throughout the human gastrointestinal tract and (2) shown for the first time that a proportion of this BLI closely resembles porcine GRP.     

Oxytocin is expressed throughout the human gastrointestinal tract

BACKGROUND/AIM: Several studies have described that oxytocin exerts stimulatory or inhibitory effects on gut functions. Recently, mRNA for oxytocin and its receptor was found throughout the entire human gastrointestinal (GI) tract. The aim of this study was to examine the cellular localization and distribution of the corresponding proteins. MATERIAL AND METHODS: Full-thickness biopsies from 24 patients, covering the entire GI tract, were collected during operations at the Department of Surgery in Malm? and Lund. The biopsies were taken from non_affected margins. The biopsies were fixed by immersion, rinsed in buffered sucrose, and kept frozen at 70 degrees C. Indirect immunofluorescence with primary antibodies to oxytocin and its receptor was used. RESULTS: Oxytocin was expressed in nerve cell bodies and nerve fibres in the myenteric and submucous ganglia all along the GI tract. Immunoreactive nerve cell bodies in myenteric ganglia predominated in the proximal (antrum and duodenum) and distal gut, while those in the submucous ganglia were more numerous in the ileum and colon. The oxytocin receptor was not detectable by two different antibodies in any tissue in the GI tract. CONCLUSION: Oxytocin is expressed in the myenteric and submucous ganglia and nerve fibres along the entire human GI tract. The role for oxytocin in the physiology and pathophysiology of the bowel remains to be settled.     

Identification of gastrin-secreting cells and cholecystokinin-secreting cells in the gastrointestinal tract of the human fetus and adult man

Summary Gastrin-and cholecystokinin (C.C.K.)-containing cells were detected by using anti-gastrin and anti-C.C.K. sera in the gastrointestinal tract of human fetuses and premature infants and in the stomach and duodenum of adult man obtained by biopsy from eight patients with normal gastro-duodenal endoscopy. The specificity of immunocytological reactions was ascertained by studying the inhibition of the reaction by gastrin, C.C.K., secretin, somatostatin, glucagon, insulin, serotonin, histamin, caerulein and octapeptide of C.C.K. In adult man, the gastrin cells are located only in the antrum and juxtapyloric region; C.C.K. was detected in the duodenum. In the human fetus, the first gastrin cells are seen in the antrum at 14 weeks of age and in the duodenum as early as 10 weeks; the C.C.K. cells are seen in the small intestine at 10 weeks of age. Acknowledgements. The authors should like to thank Professors Magnin and Liaras, Hôpital Edouard Herriot, M. Dumont, Hôpital de la Croix-Rousse, Notter et Garmier, Hôtel-Dieu, Bethenod, Hôpital Debrousse, Lyon, for their cooperation. We also thank Professor R. Guillemin, the Salk Institute, La Jolla, California, Doctor M.P. Dubois, I.N.R.A., Station de Physiologie de la Reproduction, Nouzilly, Mme Vagne, U. 45, I.N.S.E.R.M. and Professor Y. Minaire, Hôpital Edouard Herriot, Lyon, for their donations. This work was supported by a grant from the Institut National de la Santé et de la Recherche Médicale