Morphological and pathological changes of Eustachian tube mucosa in an animal model of eosinophilic otitis media.

INTRODUCTION: Eosinophilic otitis media is an intractable otitis media and a fairly common middle ear disease. However, the pathogenesis of eosinophilic otitis media is obscure. OBJECTIVE: To observe the pathological and ultrastructural changes of the Eustachian tube mucosal epithelium in rats with eosinophilic otitis media and further explore the pathogenesis of eosinophilic otitis media. METHODS: Animals were intraperitoneally injected with 2000 mg ovalbumin and 100 mg aluminum hydroxide (alum) on day 0, followed by 100 mg ovalbumin and 100 mg alum injection on days 7 and 14. Next they were topically boosted by daily application of 100 mg ovalbumin solution via nasal drip and intratympanic injection of 0.1 mL ovalbumin (1000 mg/mL) in the right ear (group A, n = 80) and 0.1 mL saline in the left ear as control (group B, n = 80) starting on day 21 and continuing for 14 days. The temporal bones were dissected on the 35th, 38th, 41st and 43rd day separately under anesthesia. Scanning electron microscopy, hematoxylin-eosin and toluidine blue staining were used to observe the pathological and morphological changes of Eustachian tube mucosa stained samples. Moreover, inflammatory cells and cilia were counted. RESULTS: The epithelium of the Eustachian tube in group A was swollen and thickened. The cilia were arranged in a disorderly manner and partially detached. Eosinophils infiltrated the submucosal layer of the Eustachian tube, and their number increased significantly compared with that in group B (p < 0.05). Simultaneously, mast cell degranulation was observed in group A. Scanning electron microscopy revealed that the cilia were lodged and gathered along the whole length of Eustachian tube in group A. Ciliated cell density was significantly lower than that in Group B (p < 0.01). CONCLUSION: In the eosinophilic otitis media model, allergy caused significant changes in pathology and morphology of the Eustachian tube mucosa, affecting the normal function of the Eustachian tube which played an important role in the occurrence and development of eosinophilic otitis media.

Transcriptome analyses to reveal the dynamic change mechanism of pigeon magnum during one egg-laying cycle.

We analyzed the transcriptome of pigeon magnum in three stages (C1: pre-ovulation, C2: post-ovulation, C3: 5-6 days after ovulation) to elucidate the molecular and cellular events associated with morphological changes during the laying cycle. We observed that C1 was highly developed, apoptosis rate was highest in C2, and C3 attained the smallest size. Through RNA-sequencing, we obtained 54,764,938 (97.2%) high-quality clean reads that aligned to 20,767 genes. Gene expression profile analysis showed the greatest difference between C1 and C3; 3966 differentially expressed genes (DEGs) were identified, of which 2250 genes were upregulated and 1716 genes were downregulated in C1. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed that protein processing and transport activities were prominent in C1, and upregulated genes included those related to signal recognition particle (SRP), signal recognition particle receptor (SRPR), translocon, GRP78, RRBP1, TRAP, TRAM1, and OST. Egg white protein-related gene expression was highest, with OVALY being the most highly expressed. In C2, apoptosis-related gene expression was higher than in C1, and fatty acid metabolism was active, which may be correlated with magnum tissue regression. Collagen- and laminin-related gene expression was prominent in C1 and C3, indicating roles in egg white protein generation and magnum reconstruction. PR gene expression was highest and exhibited drastic change in the three groups, indicating that PR and its regulation may be involved in changes in magnum morphology and function. Through the identification and functional analysis of DEGs and other crucial genes, this may contribute to understand the egg white protein production, magnum tissue regression, and magnum regeneration mechanisms.

Colitis nucleomigrans: The third type of microscopic colitis (part 2). An ultrastructural study.

In the preceding article (part 1), we proposed the third type of microscopic colitis: colitis nucleomigrans (CN). Microscopically, the nuclei of surface-lining columnar cells were migrated in chain to the middle part of the cells, and apoptotic nuclear debris was scattered in the cytoplasm beneath the nuclei. For ultrastructural analysis, buffered formalin-fixed biopsy tissue of CN (n = 2) was dug out of paraffin blocks. After deparaffinization, tissue blocks were prepared with conventional sequences. Ultrathin sections were stained with uranyl acetate and lead citrate. Fine morphological preservation was satisfactory even after paraffin embedding. Apoptotic nuclear debris was localized within the cytoplasm beneath the migrated nuclei of the surface-lining columnar cells. Abnormality of cytoskeletal filaments (actin, cytokeratin and tubulin) was scarcely recognized in the epithelial cytoplasm. Macrophages located in the uppermost part of the lamina propria phagocytized electron-dense globular materials. Intraepithelial lymphocytes with scattered dense bodies were observed among the columnar cells. We suppose that altered apoptotic processes in the colorectal surface-lining epithelial cells may be involved in the pathogenesis of CN. Mechanisms of nuclear migration to the unusual position or impairment of nuclear anchoring to the basal situation in the surface-lining epithelial cells remain unsettled, because cytoskeletal components showed little ultrastructural abnormality.

Morphological studies on the gills of the European hake (Merluccius merluccius, Linnaeus, 1758).

The current work gives concern to study the morphology of the Merluccius merluccius gills by using gross morphology, scanning electron microscopy (SEM), and light microscopy. The findings of the present study revealed that the gill system consisted of four pairs of gill arches which carry the gill filaments on the convex border and gill rakers on the concave border of them. SEM results revealed that the rakers and the spines distribution on the first gill arch differed from that of the other three gill arches on the lateral and medial surfaces. On the surface the gill filaments, there were longitudinal ridges that carried pores of chloride cells and mucous cells. The histological examination revealed that, the gill arch composed of hyaline cartilage that presented in the form of cups. Each cup consisted of central cartilagenous core and peripheral cartilagenous matrix. The gill filaments composed of cartilaginous bar of peripheral cartilaginous matrix and central cartilaginous core extended from the gill arches and covered by an epithelial layers with a few mucous cells permeate it, and chloride cells were straggly in the interlamellar epithelium. Each gill filament carried several leaves like secondary lamellae on both sides of it. The epithelium, which lined the secondary lamellae, composed of epithelial pavement cells, some mucous cells, and pillar cells.

Lamina propria: The connective tissue of rat urinary bladder mucosa.

To describe and illustrate the structure of the propria, the bladder of adult rats was fixed in controlled conditions of distension and examined by light and electron microscopy. The lamina propria, ~50 µm thick in the distended bladder, consists of a superficial part (the cellular component), adjacent to the urothelium, rich in nerves, capillaries, fibroblasts and thin bundles of collagen, and a deep, thicker part (the fibrous component), adjacent to the detrusor, rich in large collagen fibres and with few fibroblasts. In the cellular part there is an extensive plexus of afferent nerve fibers and a dense capillary network (with numerous pericytes), lying close to the urothelium, that is unique to the bladder. The main resident cells are fibroblasts, adhering to each other at the end of laminar extensions without forming specialized junctions. The deep part of the lamina propria is made of thick collagen fibers, interwoven and crisscrossing each other, with a few fibroblasts in the interstitial spaces between them. In summary, the superficial part of the lamina propria has most of the bladder afferent nerves, contains many fibroblasts and has a network of suburothelial capillaries. The deep part as a whole forms an ovoid balloon of woven fibrous material that is acted upon by the detrusor musculature attached to its outer surface. The lamina propria is a strong fibrous barrier between urothelium and musculature. The abundance of collagen points to the main role for its fibroblasts, that is, the production of collagen fibrils, assisting the mechanical role of the lamina propria.

The histopathological, cytopathological and ultrastructural effects of carbaryl on gills of Oreochromis niloticus (Linnaeus, 1758).

Ultrastructural and histopathological reponses in the organs of living organisms are important and useful tools to determine the health condition and the effects of pollutants, such as pesticides, on the organisms. The aim of this study is to determine possible histopathological, cytopathological and ultrastructural alterations in gills of Oreochromis niloticus individuals exposed to 850 µg/L carbaryl standart at 7th, 14th and 21st days with light and electron microscopes. The fish were exposed to carbaryl for 21 days and the histopatological, ultrastructural and cytopathological alterations occuring in the gill tissues of organisms were determined by light, Scanning and Transmission Electron Microscopes (SEM and TEM). At the end of the study, it was observed that carbaryl caused both histopathological and cytopathological changes in the gills of O. niloticus. It has been determined that the most of the pathological changes in the exposed organisms are the metabolic defence reactions.

The structure of the skin, types and distribution of mucous cell of yangtze sturgeon ( Acipenser dabryanus ) / La estructura de la piel, los tipos y distribución de las células mucosas del esturión yangtze ( Acipenser dabryanus )

The structural characteristics of the skin, types and distribution of mucous cells of Yangtze sturgeon (Acipenser dabryanus) were studied at the light microscope level, stained with Haematoxylin-eosin (HE) and Alcian blue-periodie acid Schiff (ABPAS). The skin of both was composed of epidermis and dermis. The dermis was divided into stratum spongiosum and stratum compactum. The stained color of stratum compactum was stained more deeply than that of stratum spongiosum. The skin thickness displayed differences in the fish at different body positions. The thickest of epidermis layer was on the dorsal region for Yangtze sturgeon, reversely, the thinnest was the mandibular region; Stratum spongiosum on the mandibular region was the thickest, the stratum spongiosum of the maxillary region was not obvious. In summary, keratinized spines, a kind of keratin derivative, are widely distributed in the mandibular, ventral, dorsal, and caudal peduncle skin surface for Yangtze sturgeon, and some pit organs mainly present in the skin surface of the maxillary and ventral regions. In short, the small amount of mucous cells in the skin of Yangtze sturgeon and the type of mucous cell were main Type IV, nevertheless there was a distribution of a few Type III.

Se estudiaron las características estructurales de la piel, los tipos y la distribución de las células mucosas del esturión Yangtze (Acipenser dabryanus) con microscopio de luz, teñidas con hematoxilina-eosina (HE) y azul alcián-ácido de Schiff (AB-PAS). La piel estaba compuesta por epidermis y dermis. La dermis se dividía en estrato esponjoso y estrato compacto. El grosor de la piel mostró diferencias en los peces en diferentes posiciones del cuerpo. La capa más gruesa de la epidermis se observó en la región dorsal del esturión Yangtze; a la inversa, la más delgada en la región mandibular. El estrato esponjoso en la región mandibular era el más grueso, el estrato esponjoso de la región maxilar no era visualizado. En resumen, las espinas queratinizadas, un tipo derivado de la queratina, estaban ampliamente distribuidas en la superficie de la piel del pedúnculo mandibular, ventral, dorsal y caudal en el esturión Yangtze, y algunos órganos en fosas, presentes principalmente en la superficie de la piel de las regiones mandibular y ventral. En resumen, la pequeña cantidad de células mucosas en la piel del esturión Yangtze y el tipo de célula mucosa eran células principales tipo IV, sin embargo, se observaron algunas células tipo III.

Biological properties of a bionic scaffold for esophageal tissue engineering research.

Polyurethane is a good matrix material with wide application prospects in tissue engineering because of its adjustable and mechanical properties. A novel biodegradable crosslinked poly(ester urethane) (CPU) with flexible poly(caprolactone) (PCL) and hydrophilic poly(ethylene glycol) (PEG) components has been synthesized using a ferric iron catalyst in our laboratory. In the present study, to promote the interaction between the CPU material and cells, the material was superficially modified by silk fibroin (SF) grafting using an aminolysis and glutaraldehyde crosslinking method to achieve a biocompatible material, CPU-SF. Considering the esophageal-specific architecture, three types of scaffolds were fabricated. S1 was a CPU-SF channel (200 µm in diameter and 30 µm in depth with 30 µm of wall thickness) to support muscle regeneration; S2 was the decellularized matrix of the esophageal mucosa/submucosa obtained by enzyme treatment; and S3 was a combination of S1 and S2, aiming to promote esophageal regeneration with histological structure and function. The biological properties and functions of the materials and scaffolds were investigated by qualitative and quantitative analyses using scanning electron microscopy, immunofluorescence staining, cell adhesion and proliferation measurements, and western blotting technology. The results showed that esophageal smooth muscle cells (SMCs) and epithelial cells (ECs) were very well supported by the scaffolds. In particular, SMCs exhibited guided directional growth and ECs infiltrated the acellular mucosa with retained biological functions when co-cultured on the composite scaffold S3. These findings suggest that the composite bionic scaffold will be a good alternative for esophageal replacement.

Dynamic changes in basal lamina fenestrations in rat intestinal villous epithelium under high-fat diet condition.

The basal lamina of the villous epithelium in the small intestine has numerous fenestrations, which are produced by leukocytes for their intraepithelial migration. We previously showed that these fenestrations change due to the dynamics of migrating leukocytes in response to dietary conditions and suggested the possibility that this change is related to the regulation of the absorption of large-sized nutrients such as chylomicrons. The present study was, thus, designed to investigate structural changes in basal lamina fenestrations in response to a high-fat diet. The ultrastructure of the intestinal villi in the rat upper jejunum was investigated by electron microscopy of tissue sections in both the normal and the high-fat diet groups, and the fenestrations in the villous epithelium of rat upper jejunum were studied by scanning electron microscopy of osmium macerated/ ultrasonicated tissues. The present study showed that free cells adhering to the fenestrations increased in the upper jejunum two hours after feeding high-fat diet and the size of the fenestrations in this region also increased after feeding high-fat diet for 2 days. This enlargement of fenestrations may play an important role in increasing the efficiency of lipid absorption by facilitating the movement of chylomicrons from the intercellular space to the lamina propria.

Early studies of airway submucosal glands.

This historical article provides a comprehensive review of early research on the structure and function of airway submucosal glands. The literature before 1950 or so, is virtually unknown, but in addition to being of historical interest it contains much of relevance to current research. Airway glands were first mentioned in 1602. The first description of their general form, size, and distribution was in 1712. Gland morphology was determined in 1827 by injecting mercury into their openings. Wax was later used. Detailed comparative information for all regions of the tracheobronchial tree was provided by Frankenhauser in 1879 (Untersuchungen uber den bau der Tracheo-Bronchial-Schleimhaut). Histological studies began in 1870, and by the end of the 19th century, all the major histological features had been described. The first physiological studies on airway mucous secretion were published in 1892. Kokin, in 1896 (Archiv für die gesamte Physiologie des Menschen und der Tiere 63: 622-630), was the first to measure secretion from individual glands. It was not, however, until 1933 that gland secretion was quantified. This early literature raises important questions as to the role of the collecting duct epithelium in modifying primary secretions. It also provides perhaps the most accurate measure of basal gland secretion in vivo.

Structure and Distribution of an Unrecognized Interstitium in Human Tissues.

Confocal laser endomicroscopy (pCLE) provides real-time histologic imaging of human tissues at a depth of 60-70 µm during endoscopy. pCLE of the extrahepatic bile duct after fluorescein injection demonstrated a reticular pattern within fluorescein-filled sinuses that had no known anatomical correlate. Freezing biopsy tissue before fixation preserved the anatomy of this structure, demonstrating that it is part of the submucosa and a previously unappreciated fluid-filled interstitial space, draining to lymph nodes and supported by a complex network of thick collagen bundles. These bundles are intermittently lined on one side by fibroblast-like cells that stain with endothelial markers and vimentin, although there is a highly unusual and extensive unlined interface between the matrix proteins of the bundles and the surrounding fluid. We observed similar structures in numerous tissues that are subject to intermittent or rhythmic compression, including the submucosae of the entire gastrointestinal tract and urinary bladder, the dermis, the peri-bronchial and peri-arterial soft tissues, and fascia. These anatomic structures may be important in cancer metastasis, edema, fibrosis, and mechanical functioning of many or all tissues and organs. In sum, we describe the anatomy and histology of a previously unrecognized, though widespread, macroscopic, fluid-filled space within and between tissues, a novel expansion and specification of the concept of the human interstitium.

Ultrastructural and Immunohistochemical Study on the Lamina Propria Cells Beneath Paneth Cells in the Rat Ileum.

Paneth cells secrete bactericidal substances in response to bacterial proliferation on the mucosal surface without directly contacting bacteria. However, the induction mechanism of this transient secretion has not been clarified, although nervous system and/or immunocompetent cells in the lamina propria (LP) might be involved. In this study, we ultrastructurally and immunohistochemically investigated which LP cells are localized beneath Paneth cells and examined the relationship between the Paneth cell-derived cellular processes which extended into the LP and the LP cells. The results showed that various cells-including blood capillary, subepithelial stromal cell, and nerve fiber-were present in the LP beneath Paneth cells. Endothelial cells of blood capillary were the cells most frequently found in this location; they were situated within 1 µm of the Paneth cells and possessed fenestration on the surfaces adjacent to Paneth cells. The Paneth cells rarely extended the cellular processes toward the LP across the basal lamina. Most of the cellular processes of Paneth cells contacted the subepithelial stromal cells. Immunohistochemistry revealed that the CD34+ CD31- αSMA- stromal cells preferentially localized in the LP beneath the intestinal crypt base, while PDGFRαhi αSMA+ stromal cells mainly localized around the lateral portions of the intestinal crypt and PDGFRαhi αSMA- stromal cells localized in the intestinal villus. From these findings, the existence of blood capillaries beneath Paneth cells might reflect the active exocrine function of Paneth cells. Furthermore, subepithelial stromal cells, probably with a CD34+ CD31- αSMA- PDGFRα-/lo phenotype, beneath the crypt base might affect Paneth cell activity by interacting with their cellular processes. Anat Rec, 301:1074-1085, 2018. © 2018 Wiley Periodicals, Inc.

Adaptive changes of telocytes in the urinary bladder of patients affected by neurogenic detrusor overactivity.

Urinary bladder activity involves central and autonomic nervous systems and bladder wall. Studies on the pathogenesis of voiding disorders such as the neurogenic detrusor overactivity (NDO) due to suprasacral spinal cord lesions have emphasized the importance of an abnormal handling of the afferent signals from urothelium and lamina propria (LP). In the LP (and detrusor), three types of telocytes (TC) are present and form a 3D-network. TC are stromal cells able to form the scaffold that contains and organizes the connective components, to serve as guide for tissue (re)-modelling, to produce trophic and/or regulatory molecules, to share privileged contacts with the immune cells. Specimens of full thickness bladder wall from NDO patients were collected with the aim to investigate possible changes of the three TC types using histology, immunohistochemistry and transmission electron microscopy. The results show that NDO causes several morphological TC changes without cell loss or network interruption. With the exception of those underlying the urothelium, all the TC display signs of activation (increase in Caveolin1 and caveolae, αSMA and thin filaments, Calreticulin and amount of cisternae of the rough endoplasmic reticulum, CD34, euchromatic nuclei and large nucleoli). In all the specimens, a cell infiltrate, mainly consisting in plasma cells located in the vicinity or taking contacts with the TC, is present. In conclusion, our findings show that NDO causes significant changes of all the TC. Notably, these changes can be interpreted as TC adaptability to the pathological condition likely preserving each of their peculiar functions.

3D-electron microscopic characterization of interstitial cells in the human bladder upper lamina propria.

AIMS: To explore the ultrastructure of interstitial cells in the upper lamina propria of the human bladder, to describe the spatial relationships and to investigate cell-cell contacts. METHODS: Focused ion beam scanning electron microscopy (FIB-SEM), 3-View SEM and confocal laser scanning microscopy were used to analyze the 3D ultrastructure of the upper lamina propria in male and female human bladders. RESULTS: 3View-SEM image stacks as large as 59 × 59 × 17 µm3 (xyz) at a resolution of 16 × 16 × 50 nm3 and high resolution (5 × 5 × 10 nm3 ) FIB-SEM stacks could be analyzed. Interstitial cells with myoid differentiation (mIC) and fibroblast like interstitial cells (fIC) were the major cell types in the upper lamina propria. The flat, sheet-like ICs were oriented strictly parallel to the urothelium. No spindle shaped cells were present. We furthermore identified one branched cell (bIC) with several processes contacting urothelial cells by penetrating the basal membrane. This cell did not make any contacts to other ICs within the upper lamina propria. We found no evidence for the occurrence of telocytes in the upper lamina propria. CONCLUSIONS: Comprehensive 3D-ultrastructural analysis of the human bladder confirmed distinct subtypes of interstitial cells. We provide evidence for a foremost unknown direct connection between a branched interstitial cell and urothelial cells of which the functional role has still to be elucidated. 3D-ultrastructure analyses at high resolution are needed to further define the subpopulations of lamina propria cells and cell-cell interactions.

Comparative study of the organisation and phenotypes of bladder interstitial cells in human, mouse and rat.

With most research on interstitial cells (IC) in the bladder being conducted on animal models, it remains unclear whether all structural and functional data on IC from animal models can be translated to the human context. This prompted us to compare the structural and immunohistochemical properties of IC in bladders from mouse, rat and human. Tissue samples were obtained from the bladder dome and subsequently processed for immunohistochemistry and electron microscopy. The ultrastructural properties of IC were compared by means of electron microscopy and IC were additionally characterized with single/double immunohistochemistry/immunofluorescence. Our results reveal a similar organization of the IC network in the upper lamina propria (ULP), the deep lamina propria (DLP) and the detrusor muscle in human, rat and mouse bladders. Furthermore, despite several similarities in IC phenotypes, we also found several obvious inter-species differences in IC, especially in the ULP. Most remarkably in this respect, ULP IC in human bladder predominantly displayed a myoid phenotype with abundant presence of contractile micro-filaments, while those in rat and mouse bladders showed a fibroblast phenotype. In conclusion, the organization of ULP IC, DLP IC and detrusor IC is comparable in human, rat and mouse bladders, although several obvious inter-species differences in IC phenotypes were found. The present data show that translating research data on IC in laboratory animals to the human setting should be carried out with caution.

New insights into the cellular makeup and progenitor potential of palatal connective tissues.

The present study investigated the regenerative potential of connective tissues harvested from two palatal areas widely used as donor sites for muco-gingival surgical approaches. Connective tissue grafts (CTGs) were obtained by de-epithelialisation of a free gingival graft (deCTG) and by a split flap approach from a previous donor site (reCTG). Two types of mesenchymal stem cell (MSCs) were isolated and were named de-epithelialised MSCs (deMSCs) and re-entry MSCs (reMSCs). The cells were characterised and cellular functionality was investigated. CTGs were evaluated using immunohistochemical and ultrastructural approaches. No significant differences were observed regarding the frequency of colony-forming unit- fibroblasts, migration potential, and population doubling time between the two cell lines (p > 0.05). Both cell lines showed positivity for CD105, CD73, CD90, and CD44 and negative expression for CD34/45, CD14, CD79a, and HLA-DR. MSCs from both cell lines successfully differentiated into osteogenic, adipogenic, and chondrogenic lineages. Cells expressing antigens characteristic of CD34+ stromal cells (CD34+, αSMA-, CD31-) were traced in both CTGs. Ultrastructural analysis highlighted the presence of putative progenitors, namely fibroblasts,-in the pericapillary regions and in remote regions of the lamina propria- and pericytes-surrounding the capillaries. This study provides supplementary arguments for the use of CTG grafts in clinical practice due to the presence of putative progenitor cell. However, results were inconclusive regarding clinical decision-making to determine optimal harvesting area. Prior harvesting in the donor area did not appear to alter the regenerative capabilities of the connective tissue.

Structural Reorganization of the Vaginal Mucosa in Stress Urinary Incontinence under Conditions of Er:YAG Laser Treatment.

Structural characteristics of the vaginal mucosa in stress incontinence and its correction by IncontiLase technology were studied. Studies of vaginal biopsy specimens before the exposure showed degenerative and atrophic changes in the stratified squamous epithelium, disorganization of fibrillar structures of the intercellular matrix, and microcirculatory disorders. Studies after Er:YAG laser exposure showed signs of neocollagenogenesis and elastogenesis, foci of neoangiogenesis, reduction of epithelial degeneration and atrophy, and an increase of the fibroblast population. Morphometry showed that the volume density of blood capillaries and the thickness of the epithelial layer increased by 61.1 and 64.5%, respectively. The use of IncontiLase technology in stress incontinence led to structural reorganization of the vaginal mucosa, improving its morphology and function and alleviating the symptoms of incontinence.

Human Three-Dimensional Endometrial Epithelial Cell Model To Study Host Interactions with Vaginal Bacteria and Neisseria gonorrhoeae.

Colonization of the endometrium by pathogenic bacteria ascending from the lower female reproductive tract (FRT) is associated with many gynecologic and obstetric health complications. To study these host-microbe interactions in vitro, we developed a human three-dimensional (3-D) endometrial epithelial cell (EEC) model using the HEC-1A cell line and the rotating wall vessel (RWV) bioreactor technology. Our model, composed of 3-D EEC aggregates, recapitulates several functional/structural characteristics of human endometrial epithelial tissue, including cell differentiation, the presence of junctional complexes/desmosomes and microvilli, and the production of membrane-associated mucins and Toll-like receptors (TLRs). TLR function was evaluated by exposing the EEC aggregates to viral and bacterial products. Treatment with poly(I·C) and flagellin but not with synthetic lipoprotein (fibroblast-stimulating lipoprotein 1 [FSL-1]) or lipopolysaccharide (LPS) significantly induced proinflammatory mediators in a dose-dependent manner. To simulate ascending infection, we infected EEC aggregates with commensal and pathogenic bacteria: Lactobacillus crispatus, Gardnerella vaginalis, and Neisseria gonorrhoeae All vaginal microbiota and N. gonorrhoeae efficiently colonized the 3-D surface, localizing to crevices of the EEC model and interacting with multiple adjacent cells simultaneously. However, only infection with pathogenic N. gonorrhoeae and not infection with the other bacteria tested significantly induced proinflammatory mediators and significant ultrastructural changes to the host cells. The latter observation is consistent with clinical findings and illustrated the functional specificity of our system. Additionally, we highlighted the utility of the 3-D EEC model for the study of the pathogenesis of N. gonorrhoeae using a well-characterized ΔpilT mutant. Overall, this study demonstrates that the human 3-D EEC model is a robust tool for studying host-microbe interactions and bacterial pathogenesis in the upper FRT.