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Philosophical Transactions of the Royal... Dec 2022The amnion is an extraembryonic tissue that evolutionarily allowed embryos of all amniotes to develop in a transient and local aquatic environment. Despite the... (Review)
Review
The amnion is an extraembryonic tissue that evolutionarily allowed embryos of all amniotes to develop in a transient and local aquatic environment. Despite the importance of this tissue, very little is known about its formation and its molecular characteristics. In this review, we have compared the basic organization of the extraembryonic membranes in amniotes and describe the two types of amniogenesis, folding and cavitation. We then zoom in on the atypical development of the amnion in mice that occurs via the formation of a single posterior amniochorionic fold. Moreover, we consolidate lineage tracing data to better understand the spatial and temporal origin of the progenitors of amniotic ectoderm, and visualize the behaviour of their descendants in the extraembryonic-embryonic junctional region. This analysis provides new insight on amnion development and expansion. Finally, using an online-available dataset of single-cell transcriptomics during the gastrulation period in mice, we provide bioinformatic analysis of the molecular signature of amniotic ectoderm and amniotic mesoderm. The amnion is a tissue with unique biomechanical properties that deserves to be better understood. This article is part of the theme issue 'Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom'.
Topics: Amnion; Animals; Gastrulation; Mesoderm; Mice
PubMed: 36252226
DOI: 10.1098/rstb.2021.0258 -
Current Opinion in Gastroenterology Nov 2015To highlight recent developments in the field of gastroduodenal mucosal defense with emphasis on lumen-gut interactions. (Review)
Review
PURPOSE OF REVIEW
To highlight recent developments in the field of gastroduodenal mucosal defense with emphasis on lumen-gut interactions.
RECENT FINDINGS
There has been a growing interest in the physiological functions of luminal chemosensors present from tongue to colon that detect organic molecules in the luminal content associated with nutrient ingestion, usually associated with specialized cells, in particular the enteroendocrine cells. These receptors transduce the release of peptide hormones, in particular proglucagon-derived products such as the glucagon-like peptides (GLPs), which have profound effects on gut function and on metabolism. Luminal chemosensors transduce GLP release in response to changes in the cellular environment, as part of the mechanism of nutrient chemosensing. GLP-2 has important trophic effects on the intestinal mucosa, including increasing the proliferation rate of stem cells and reducing transmucosal permeability to ions and small molecules, in addition to increasing the rate of duodenal bicarbonate secretion. GLP-1, although traditionally considered an incretin that enhances the effect of insulin on peripheral tissues, also has trophic effects on the intestinal epithelium.
SUMMARY
A better understanding of the mechanisms that mediate GLP release can further illuminate the importance of nutrient chemosensing as an important component of the mechanism that mediates the trophic effects of luminal nutrients. GLP-1 and GLP-2 are already in clinical use for the treatment of diabetes and intestinal failure. Improved understanding of the control of their release and their end-organ effects will identify new clinical indications and interventions that enhance their release.
Topics: Bile Acids and Salts; Chemoreceptor Cells; Duodenum; Gastric Mucosa; Gastrointestinal Diseases; Glucagon-Like Peptides; Humans; Intestinal Mucosa; Nutritional Physiological Phenomena; Receptors, G-Protein-Coupled
PubMed: 26376476
DOI: 10.1097/MOG.0000000000000211 -
The Cochrane Database of Systematic... Feb 2016A pterygium is a fleshy, wing-shaped growth from the conjunctiva, crossing over the limbus onto the cornea. Prevalence ranges widely around the world. Evidence suggests... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
A pterygium is a fleshy, wing-shaped growth from the conjunctiva, crossing over the limbus onto the cornea. Prevalence ranges widely around the world. Evidence suggests that ultraviolet light is a major contributor in the formation of pterygia. Pterygia impair vision, limit eye movements, and can cause eye irritation, foreign body sensation, and dryness. In some susceptible patients, the pterygium can grow over the entire corneal surface, blocking the visual axis.Surgery is the only effective treatment for pterygium, though recurrences are common. With simple excision techniques (that is, excising the pterygium and leaving bare sclera), the risk of recurrence has been reported to be upwards of 80%. Pterygium excision combined with a tissue graft has a lower risk of recurrence. In conjunctival autograft surgery, conjunctival tissue from another part of the person's eye along with limbal tissue is resected in one piece and used to cover the area from which the pterygium was excised. Another type of tissue graft surgery for pterygium is amniotic membrane graft, whereby a piece of donor amniotic membrane is fixed to the remaining limbus and bare sclera area after the pterygium has been excised.
OBJECTIVES
The objective of this review was to assess the safety and effectiveness of conjunctival autograft (with or without adjunctive therapy) compared with amniotic membrane graft (with or without adjunctive therapy) for pterygium. We also planned to determine whether use of MMC yielded better surgical results and to assess the direct and indirect comparative costs of these procedures.
SEARCH METHODS
We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (Issue 10, 2015), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to November 2015), EMBASE (January 1980 to November 2015), PubMed (1948 to November 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to November 2015), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (last searched 21 November 2014), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 23 November 2015.
SELECTION CRITERIA
We included in this review randomized controlled trials that had compared conjunctival autograft surgery (with or without adjunctive therapy) with amniotic membrane graft surgery (with or without adjunctive therapy) in people with primary or recurrent pterygium.
DATA COLLECTION AND ANALYSIS
Two review authors independently screened search results and assessed full-text reports from among the potentially eligible trials. Two review authors independently extracted data from the included trials and assessed the trial characteristics and risk of bias. The primary outcome was the risk of recurrence of pterygium at 3 months and 6 months after surgery. We combined results from individual studies in meta-analyses using random-effects models. Risk of recurrence of pterygium was reported using risk ratios to compare conjunctival autograft with amniotic membrane transplant.
MAIN RESULTS
We identified 20 studies that had analyzed a total of 1947 eyes of 1866 participants (individual studies ranged from 8 to 346 participants who were randomized). The studies were conducted in eight different countries: one in Brazil, three in China, three in Cuba, one in Egypt, two in Iran, two in Thailand, seven in Turkey, and one in Venezuela. Overall risk of bias was unclear, as many studies did not provide information on randomization methods or masking to prevent performance and detection bias.The risk ratio for recurrence of pterygium using conjunctival autograft versus amniotic membrane transplant was 0.87 (95% confidence interval (CI) 0.43 to 1.77) and 0.53 (95% CI 0.33 to 0.85) at 3 months and 6 months, respectively. These estimates include participants with primary and recurrent pterygia. We performed a subgroup analysis to compare participants with primary pterygia with participants with recurrent pterygia. For participants with primary pterygia, the risk ratio was 0.92 (95% CI 0.37 to 2.30) and 0.58 (95% CI 0.27 to 1.27) at 3 months and 6 months, respectively. We were only able to estimate the recurrence of pterygia at 6 months for participants with recurrent pterygia, and the risk ratio comparing conjunctival autograft with amniotic membrane transplant was 0.45 (95% CI 0.21 to 0.99). One included study was a doctoral thesis and did not use allocation concealment. When this study was excluded in a sensitivity analysis, the risk ratio for pterygium recurrence at 6 months' follow-up was 0.43 (95% CI 0.30 to 0.62) for participants with primary and recurrent pterygium. One of the secondary outcomes, the proportion of participants with clinical improvement, was analyzed in only one study. This study reported clinical outcome as the risk of non-recurrence, which was seen in 93.8% of participants in the conjunctival limbal autograft group and 93.3% in the amniotic membrane transplant group at 3 months after surgery.We did not analyze data on the need for repeat surgery, vision-related quality of life, and direct and indirect costs of surgery due to an insufficient number of studies reporting these outcomes.Thirteen studies reported adverse events associated with conjunctival autograft surgery and amniotic membrane transplant surgery. Adverse events that occurred in more than one study were granuloma and pyogenic granuloma and increased intraocular pressure. None of the included studies reported that participants had developed induced astigmatism.
AUTHORS' CONCLUSIONS
In association with pterygium excision, conjunctival autograft is associated with a lower risk of recurrence at six months' after surgery than amniotic membrane transplant. Participants with recurrent pterygia in particular have a lower risk of recurrence when they receive conjunctival autograft surgery compared with amniotic membrane transplant. There are few studies comparing the two techniques with respect to visual acuity outcomes, and we identified no studies that reported on vision-related quality of life or direct or indirect costs. Comparison of these two procedures in such outcome measures bears further investigation. There were an insufficient number of studies that used adjunctive mitomycin C to estimate the effects on pterygium recurrence following conjunctival autograft or amniotic membrane transplant.
Topics: Amnion; Autografts; Conjunctiva; Humans; Pterygium; Randomized Controlled Trials as Topic; Recurrence; Time Factors
PubMed: 26867004
DOI: 10.1002/14651858.CD011349.pub2 -
Annual Review of Immunology 2015The diverse microbial populations constituting the intestinal microbiota promote immune development and differentiation, but because of their complex metabolic... (Review)
Review
The diverse microbial populations constituting the intestinal microbiota promote immune development and differentiation, but because of their complex metabolic requirements and the consequent difficulty culturing them, they remained, until recently, largely uncharacterized and mysterious. In the last decade, deep nucleic acid sequencing platforms, new computational and bioinformatics tools, and full-genome characterization of several hundred commensal bacterial species facilitated studies of the microbiota and revealed that differences in microbiota composition can be associated with inflammatory, metabolic, and infectious diseases, that each human is colonized by a distinct bacterial flora, and that the microbiota can be manipulated to reduce and even cure some diseases. Different bacterial species induce distinct immune cell populations that can play pro- and anti-inflammatory roles, and thus the composition of the microbiota determines, in part, the level of resistance to infection and susceptibility to inflammatory diseases. This review summarizes recent work characterizing commensal microbes that contribute to the antimicrobial defense/inflammation axis.
Topics: Adaptive Immunity; Animals; Autoimmune Diseases; Computational Biology; Diet; Disease Resistance; Disease Susceptibility; Gastroenteritis; Gastrointestinal Microbiome; Host-Pathogen Interactions; Humans; Immunity, Innate; Immunity, Mucosal; Intestinal Mucosa; Metabolome; Neoplasms; Vitamins
PubMed: 25581310
DOI: 10.1146/annurev-immunol-032713-120238 -
Biochimica Et Biophysica Acta Feb 2015The liver is able to regenerate itself in response to partial hepatectomy or liver injury. This is accomplished by a complex network of different cell types and signals... (Review)
Review
The liver is able to regenerate itself in response to partial hepatectomy or liver injury. This is accomplished by a complex network of different cell types and signals both inside and outside the liver. Bile acids (BAs) are recently identified as liver-specific metabolic signals and promote liver regeneration by activating their receptors: Farnesoid X Receptor (FXR) and G-protein-coupled BA receptor 1 (GPBAR1, or TGR5). FXR is a member of the nuclear hormone receptor superfamily of ligand-activated transcription factors. FXR promotes liver regeneration after 70% partial hepatectomy (PHx) or liver injury. Moreover, activation of FXR is able to alleviate age-related liver regeneration defects. Both liver- and intestine-FXR are activated by BAs after liver resection or injury and promote liver regeneration through distinct mechanism. TGR5 is a membrane-bound BA receptor and it is also activated during liver regeneration. TGR5 regulates BA hydrophobicity and stimulates BA excretion in urine during liver regeneration. BA signaling thus represents a novel metabolic pathway during liver regeneration. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
Topics: Animals; Bile Acids and Salts; Humans; Intestinal Mucosa; Liver; Liver Regeneration; Receptors, Cytoplasmic and Nuclear; Receptors, G-Protein-Coupled; Signal Transduction
PubMed: 24878541
DOI: 10.1016/j.bbagrm.2014.05.021 -
Multimedia Manual of Cardiothoracic... Dec 2020Chronic constrictive pericarditis results from inflammation and fibrosis of the pericardium. This situation eventually leads to impairment of diastolic filling and right...
Chronic constrictive pericarditis results from inflammation and fibrosis of the pericardium. This situation eventually leads to impairment of diastolic filling and right heart failure. Once the diagnosis is made, because the disease is basically irreversible, a pericardiectomy is the mandatory treatment. The standard surgical treatment has been extensively described. The goal of this video tutorial is to render a visual explanation of the described techniques and to provide tips to help make the procedure easier to perform. The standard technique is performed through a median sternotomy, preferably without cardiopulmonary bypass if feasible. The procedure includes the complete removal of the anterior pericardium from phrenic nerve to phrenic nerve and the removal of the diaphragmatic pericardium and of part of the pericardium posterior to both phrenic nerves. Before starting the actual pericardiectomy procedure, it is useful to separate the pericardial rigid shell from the pleurae and from the diaphragm; this step allows the operator to see both phrenic nerves clearly and to give clear boundaries between the pericardium and the diaphragm, which are not often as clear as desirable due to fat, edema, inflammation, and scarring. Once a portion of the pericardium has been detached from the myocardium, it can be excised, making the portion yet to be removed more visible.
Topics: Adult; Cardiopulmonary Bypass; Heart Failure; Humans; Male; Pericardiectomy; Pericarditis, Constrictive; Pericardium; Sternotomy; Treatment Outcome
PubMed: 33399281
DOI: 10.1510/mmcts.2020.076 -
Terminal differentiation of villus tip enterocytes is governed by distinct Tgfβ superfamily members.EMBO Reports Sep 2023The protective and absorptive functions of the intestinal epithelium rely on differentiated enterocytes in the villi. The differentiation of enterocytes is orchestrated...
The protective and absorptive functions of the intestinal epithelium rely on differentiated enterocytes in the villi. The differentiation of enterocytes is orchestrated by sub-epithelial mesenchymal cells producing distinct ligands along the villus axis, in particular Bmps and Tgfβ. Here, we show that individual Bmp ligands and Tgfβ drive distinct enterocytic programs specific to villus zonation. Bmp4 is expressed from the centre to the upper part of the villus and activates preferentially genes connected to lipid uptake and metabolism. In contrast, Bmp2 is produced by villus tip mesenchymal cells and it influences the adhesive properties of villus tip epithelial cells and the expression of immunomodulators. Additionally, Tgfβ induces epithelial gene expression programs similar to those triggered by Bmp2. Bmp2-driven villus tip program is activated by a canonical Bmp receptor type I/Smad-dependent mechanism. Finally, we establish an organoid cultivation system that enriches villus tip enterocytes and thereby better mimics the cellular composition of the intestinal epithelium. Our data suggest that not only a Bmp gradient but also the activity of individual Bmp drives specific enterocytic programs.
Topics: Enterocytes; Ligands; Intestinal Mucosa; Transforming Growth Factor beta; Bone Morphogenetic Proteins; Cell Differentiation
PubMed: 37493498
DOI: 10.15252/embr.202256454 -
Immunological Reviews Sep 2021Most antibodies produced in the body are of the IgA class. The dominant cell population producing them are plasma cells within the lamina propria of the gastrointestinal... (Review)
Review
Most antibodies produced in the body are of the IgA class. The dominant cell population producing them are plasma cells within the lamina propria of the gastrointestinal tract, but many IgA-producing cells are also found in the airways, within mammary tissues, the urogenital tract and inside the bone marrow. Most IgA antibodies are transported into the lumen by epithelial cells as part of the mucosal secretions, but they are also present in serum and other body fluids. A large part of the commensal microbiota in the gut is covered with IgA antibodies, and it has been demonstrated that this plays a role in maintaining a healthy balance between the host and the bacteria. However, IgA antibodies also play important roles in neutralizing pathogens in the gastrointestinal tract and the upper airways. The distinction between the two roles of IgA - protective and balance-maintaining - not only has implications on function but also on how the production is regulated. Here, we discuss these issues with a special focus on gut and airways.
Topics: Friends; Humans; Immunity, Mucosal; Immunoglobulin A; Intestinal Mucosa; Mucous Membrane; Plasma Cells
PubMed: 34331314
DOI: 10.1111/imr.13014 -
Tissue Engineering and Regenerative... Oct 2021Vaccination has been recently attracted as one of the most successful medical treatments of the prevalence of many infectious diseases. Mucosal vaccination has been... (Review)
Review
Vaccination has been recently attracted as one of the most successful medical treatments of the prevalence of many infectious diseases. Mucosal vaccination has been interested in many researchers because mucosal immune responses play part in the first line of defense against pathogens. However, mucosal vaccination should find out an efficient antigen delivery system because the antigen should be protected from degradation and clearance, it should be targeted to mucosal sites, and it should stimulate mucosal and systemic immunity. Accordingly, mucoadhesive polymeric particles among the polymeric particles have gained much attention because they can protect the antigen from degradation, prolong the residence time of the antigen at the target site, and control the release of the loaded vaccine, and results in induction of mucosal and systemic immune responses. In this review, we discuss advances in the development of several kinds of mucoadhesive polymeric particles for mucosal vaccine delivery.
Topics: Drug Delivery Systems; Immunity, Mucosal; Mucous Membrane; Polymers; Vaccines
PubMed: 34304387
DOI: 10.1007/s13770-021-00373-w -
Biomedicine & Pharmacotherapy =... May 2023Nanodrug delivery systems have been widely used in disease treatment. However, weak drug targeting, easy to be cleared by the immune system, and low biocompatibility are... (Review)
Review
Nanodrug delivery systems have been widely used in disease treatment. However, weak drug targeting, easy to be cleared by the immune system, and low biocompatibility are great obstacles for drug delivery. As an important part of cell information transmission and behavior regulation, cell membrane can be used as drug coating material which represents a promising strategy and can overcome these limitations. Mesenchymal stem cell (MSC) membrane, as a new carrier, has the characteristics of active targeting and immune escape of MSC, and has broad application potential in tumor treatment, inflammatory disease, tissue regeneration and other fields. Here, we review recent progress on the use of MSC membrane-coated nanoparticles for therapy and drug delivery, aiming to provide guidance for the design and clinical application of membrane carrier in the future.
Topics: Membranes; Drug Delivery Systems; Cell Membrane; Nanoparticles; Mesenchymal Stem Cells; Excipients
PubMed: 36870279
DOI: 10.1016/j.biopha.2023.114451