The binding of peroxidase-labelled lectins to human endometrium in normal cyclical endometrium and endometrial adenocarcinoma

Ultrastructural analysis of the pathogenesis of Neisseria gonorrhoeae endometrial infection

We have studied gonococcal infection in human endometrium organ culture and in human primary endometrial epithelial cells using various microscopic techniques including scanning electron microscopy, transmission electron microscopy, bright field light microscopy and laser scanning confocal microscopy. Here we describe the interactions between Neisseria gonorrhoeae and human endometrial luminal epithelial cells at the ultrastructural levels. N. gonorrhoeae attached to cilia but were not observed associated with the plasma membrane of ciliated epithelial cells or internalized into ciliated epithelial cells. N. gonorrhoeae could be found in intracellular vacuoles in secretory epithelial cells. N. gonorrhoeae have diverse interactions with endometrial epithelium. These include intimate association and colocalization with asialoglycoprotein receptor (ASGP-R) and CEACAM, lamellipodia and ruffle formation and colocalization with CR3, and microvillus engagement. These studies indicate that N. gonorrhoeae utilize multiple mechanisms to associate with endometrial epithelial cells and can associate with both ciliated and secretory cells. This diversity is consistent with a role of the endometrium as a transition zone between frequently asymptomatic cervical gonorrhoea and symptomatic pelvic inflammatory disease.

Immunohistochemical detection of sepsis-induced lung injury in human autopsy material

This review addresses our present-day knowledge on the role of different cellular adhesion molecules, cytokines and glycoproteins for the detection of sepsis-induced injury in the microvasculature of the human lung using immunohistochemistry. Through the induction and modulation of endothelial cell adhesion molecules, such as E-selectin (CD 62E), the vascular endothelium controls leukocyte extravasation into tissue. E-Selectin, not expressed by unstimulated endothelium, is activated by cytokines and initiates neutrophil recruitment in sepsis-induced lung injury. Since E-selectin is strongly expressed in the pulmonary microvasculature in sepsis-associated fatalities, the immunohistochemical detection of an intense expression of E-selectin in lung tissue is a valuable diagnostic tool in the forensic postmortem elucidation of death due to sepsis. VLA-4 (CD49d/CD29) is strongly expressed on intravascular, interstitial and intra-alveolar leukocytes in sepsis-associated fatalities, whereas in non-septic fatalities an irregular weak immunoreactivity can be observed on interstitial leukocytes and no positive immunohistochemical expression can be observed on intravascular or intra-alveolar leukocytes. ICAM-1 (CD54) is strongly expressed on endothelial cells of the pulmonary microvasculature and on pulmonary macrophages and lymphocytes in sepsis-associated fatalities. In contrast, an infrequent weak immunohistochemical reaction for ICAM-1 is found on pulmonary endothelium and on perivascular leukocytes in non-septic fatalities. The up-regulation of both cellular adhesion molecules can be considered as an useful immunohistochemical postmortem marker of sepsis. Lactoferrin (LF) is an iron-binding glycoprotein located in specific (secondary) granules of leukocytes and plays a central role in the host response to infectious stimuli in providing both bacteriostatic and bactericidal protection. There is a statistically significant association between an enhanced expression of LF on pulmonary leukocytes in sepsis-related fatalities in contrast to non-septic controls. The immunohistochemical detection of an enhanced expression of LF can contribute to the postmortem discrimination between sepsis and non-septic fatalities. Application of carbohydrate-specific lectins (ConA, UEA, GSA I, GSA II, MPA, PNA, Jac, WGA, MAA, LPA, SNA) on deparaffinated lung tissue sections from sepsis-associated fatalities and control cases results to some extent in different staining patterns of alveolar epithelial cells and subepithelial seromucous glands of the bronchi. Apart from differences in binding sites for alpha-mannose, N-acetyl-neuraminic acid and alpha-(2-6)-galactose (as detected by different expression for ConA, MAA and SNA), the main finding is that no binding sites for alpha-N-acetyl-galactosamine (as investigated by MPA immunoreactivity) can be detected on alveolar epithelial cells and mucous parts of subepithelial seromucous glands in sepsis cases in contrast to the presence of such binding sites in controls. Since most intracellular pathogens persist in macrophages and epithelial cells during infection, it is likely that these pathogens contribute to a continual deprivation or consumption, respectively, of glycoproteins physiologically secreted by alveolar epithelial and glandular cells at different time points and stages of infection and may, among other mechanisms, by reducing pathogen clearance amplify the inflammatory response. Vascular endothelial growth factor (VEGF), an angiogenic and chemotactic peptide, is abundantly expressed in normal lung tissue, especially in alveolar and bronchial epithelium, glandular cells of the bronchi, and activated alveolar macrophages. Pulmonary VEGF immunostaining differs in sepsis when compared to healthy individuals. In the latter a preponderant strong VEGF immunoreaction can be found on alveolar epithelium (predominately type II pneumocytes), bronchial epithelium and glandular cells of the bronchi and bronchioli, and activated alveolar macrophages. In contrast, in sepsis no VEGF immunopositivity can beivity can be observed on bronchial epithelium or glandular cells of the bronchi and bronchioli, and no or relatively sparse VEGF immunoreactivity is found on alveolar epithelial cells. The precise mechanisms of the decreased pulmonary VEGF expression in septic patients under conditions of intensive care medicine are not clear at present. During the complex cascade of excessive pro-inflammatory and anti-inflammatory mediator release involved in the host's systemic inflammatory response in the development of sepsis-induced lung injury, VEGF expression may be suppressed in sepsis by a hitherto not identified agent or the interaction of different mediators of cellular inflammation. For the detection of sepsis-induced lung injury the aforementioned markers can be used sufficiently, e.g. to give immunohistochemical evidence of a previously undiagnosed sepsis and to confirm or rule out a presumed diagnosis of a sepsis-associated fatality. The employment of the presented immunohistochemical methods will be particularly helpful when macroscopical and routine histological autopsy findings in cases of suspected fatal sepsis are unspecific or unconvincing, respectively, and clinical data on the patient's previous history are not available. Referring to the forensic argumentation regarding causality on the subject of possibly fatal septic complications, e.g. in the sequel of diagnostic or therapeutic iatrogenic injection procedures or being relevant to pressure sore-associated fatalities, aetiopathogenetic conclusions can be optimized on the basis of the described micromorphological investigations.

The loss of lectin reactivity from human endometrium is a feature of malignant change

Changes in the cell surface glycoproteins were investigated in endometrial adenocarcinomas using eight biotin-labelled lectins (Con A, LCA, WGA, e-PHA, l-PHA, SBA, PNA, LTA) which select for the major classes of N-linked and O-linked oligosaccharides. The tissues studied were 14 normal endometria, 20 cases of simple hyperplasia and 30 endometrial adenocarcinomas. Sections were cut at 5 microns from formalin fixed paraffin embedded blocks and were stained with an avidin-peroxidase method. All normal and hyperplastic endometria contained the full range of expected saccharides (positive staining for Con A, LCA, WGA, SBA, PNA, LTA, e-PHA and l-PHA). By contrast, over half of the endometrial adenocarcinomas exhibited a loss of galactosamine (56.7%) and over a third of them failed to reveal galactose (36.7%) and fucose (30.0%) (negative staining for SBA, PNA and LTA, respectively). Interestingly, following neuraminidase treatment, galactose was identified in all adenocarcinomas studied, but the expression of galactosamine and fucose was unaffected. There was a discrete linear staining at the level of the basement membranes in a proportion of endometrial glands treated with e-PHA, l-PHA and LCA; this was continuous in normal and hyperplastic endometria, while it was fragmentary in endometrial adenocarcinomas. The loss of galactosamine reactivity from endometrial adenocarcinomas was significantly correlated with high grade differentiation, and also with the more frequent occurrence of a poor oestrogen (ER) and progesterone (PR) receptor status and with an unfavourable 5-year survival. No relationship was found between fucose reactivity and tumour differentiation, stage of disease, hormone receptor status or prognosis. It is concluded that galactosamine loss, together with reduced fucose expression, is a common feature of endometrial malignancy, and that galactosamine deficient tumours may reflect a more aggressive biological behaviour.

Aging of the human endometrium: peri-implantation phase endometrium does not show any age-dependent variation in lectin binding

OBJECTIVE

To evaluate if the peri-implantation endometrium shows age variations in lectin patterns, which suggest possible age variations in embryo-maternal recognition.

STUDY DESIGN

Peri-implantation endometria of younger ( < 30 years of age: n = 13) and older ( > 40 years of age: n = 17) normally menstruating women was studied. Endometrial specimens were routinely fixed in buffered formaline and embedded in paraffin. Sections (5 microns) were studied using seven lectins: DBA (Dolicus biflorus, binding specificity alpha-D-GalNAc), PNA (Arachis hypogea, binding specificity D-Gal (beta 1 --> 3)-D-GalNAc), SBA (Glycine max binding specificity alpha/beta-D-GalNAc > D-Gal), WGA (Triticum vulgare binding specificity (alpha-D-GlcNAc)n and sialic acid), ConA (Canavalia ensiformis binding specificity alpha-D-Man > alpha-D-Glc), LTA (Lotus tetragonolobus binding specificity alpha-L-fucose) and UEA 1 (Ulex europaeus binding specificity alpha-L-fucose).

RESULTS

No significant differences were found in the glycoconjugates sugar residue content and distribution between the endometria of women < 30 years of age and those of women > 40.

CONCLUSIONS

Our results suggest that human endometrium does not age, at least while cyclic hormonal stimulation and menstruation are present.

Assessment of lectin binding for prognosis in endometrial carcinoma

The binding of Ulex europeus agglutinin-I (UEA-I) and Peanut agglutinin (PNA) was studied in 56 endometrial carcinomas. The positive rates of UEA-I and PNA were 66%. Following neuraminidase treatment, the PNA positive rate increased from 66% to 98% and most tumors stained abundantly. UEA-I staining was unaffected. Using a combined grading system based on architectural and nuclear abnormalities, the PNA positive rates of grade 1, grade 2 and grade 3 tumors were 78%, 70% and 36%, respectively. There was no correlation between UEA-I binding and the grading systems. UEA-I binding correlated significantly with the presence of myometrial invasion and vessel permeation. Metastatic endometrial carcinomas showed a high affinity of tumor cells for UEA-I. Tissues that stained with UEA-I were those from patients with the worst prognosis. PNA and UEA-I reactivities relate to the biologic activity of endometrial carcinomas. UEA-I can serve as a prognostic marker for patients with endometrial carcinoma.

The use of lectins in histopathology

Lectins are proteins and glycoproteins extracted predominantly from plants which have the capacity to bind sugars specifically. This property makes them of interest for histopathology since they will bind to saccharides forming parts of glycoproteins and glycolipids of tissue constituents. Lectins have and can be used as reagents for mucin histochemistry, to identify specific cells, in the recognition of glycoprotein alterations in disease states, in studies of infectious diseases, and in the assessment of glycoconjugate alterations occurring with malignancy. They can be used for both light microscopic and ultrastructural localisation and various methods are available. It is important though, to consider the nature of the glycoconjugates under study and select lectins appropriately because of their varying specificities and binding characteristics. A panel of lectins should be used to study a particular configuration. Care should be taken with tissue fixation and processing. It must be remembered that an open and critical mind should be kept concerning interpretation of results. At the present time lectins have a limited value diagnostically, but the binding of Ulex europeus agglutinin to endothelium is certainly of value.