Lgr5 Does Not Vary Throughout the Menstrual Cycle in Endometriotic Human Eutopic Endometrium.

Endometriosis is characterized by the abnormal presence of endometrium outside of the uterus, resulting in pelvic pain and infertility. The leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) has been postulated to be a marker of stem cells in the endometrium. However, LGR5⁺ cells have a macrophage-like phenotype in this tissue, so it is unclear what role LGR5⁺ cells actually play in the endometrium. Macrophages serve an important function in the endometrium to maintain fertility, while LGR5⁺ cells generally have a role in tumor progression and are involved in invasion in some cancers. We sought to determine whether LGR5⁺ cells vary across the menstrual cycle in women with endometriosis and whether there are implications for LGR5 in the aggressiveness of endometriosis and reproductive outcomes. We performed immunofluorescence, flow cytometry, and primary culture in vitro experiments on eutopic and ectopic endometrium from healthy and endometriosis patients and observed that neither LGR5⁺ cells nor LGR5 expression varied throughout the cycle. Interestingly, we observed that LGR5⁺ cell percentage overexpressing CD163 (anti-inflammatory marker) was higher in healthy endometrium, suggesting that in endometriosis, endometrium presents a more pro-inflammatory phenotype that likely leads to poor obstetric outcomes. We also observed higher levels of LGR5⁺ cells in ectopic lesions compared to eutopic endometrium and specifically in deep infiltrating endometriosis, indicating that LGR5 could be involved in progression and aggressiveness of the disease.

Marked increase in rat red blood cell membrane protein glycosylation by one-month treatment with a cafeteria diet.

Background and Objectives. Glucose, an aldose, spontaneously reacts with protein amino acids yielding glycosylated proteins. The compounds may reorganize to produce advanced glycosylation products, which regulatory importance is increasingly being recognized. Protein glycosylation is produced without the direct intervention of enzymes and results in the loss of function. Glycosylated plasma albumin, and glycosylated haemoglobin are currently used as index of mean plasma glucose levels, since higher glucose availability results in higher glycosylation rates. In this study we intended to detect the early changes in blood protein glycosylation elicited by an obesogenic diet. Experimental Design. Since albumin is in constant direct contact with plasma glucose, as are the red blood cell (RBC) membranes, we analyzed their degree or glycosylation in female and male rats, either fed a standard diet or subjected to a hyper-energetic self-selected cafeteria diet for 30 days. This model produces a small increase in basal glycaemia and a significant increase in body fat, leaving the animals in the initial stages of development of metabolic syndrome. We also measured the degree of glycosylation of hemoglobin, and the concentration of glucose in contact with this protein, that within the RBC. Glycosylation was measured by colorimetric estimation of the hydroxymethylfurfural liberated from glycosyl residues by incubation with oxalate. Results. Plasma glucose was higher in cafeteria diet and in male rats, both independent effects. However, there were no significant differences induced by sex or diet in either hemoglobin or plasma proteins. Purified RBC membranes showed a marked effect of diet: higher glycosylation in cafeteria rats, which was more marked in females (not in controls). In any case, the number of glycosyl residues per molecule were higher in hemoglobin than in plasma proteins (after correction for molecular weight). The detected levels of glucose in RBC were lower than those of plasma, even when expressed in molal units, and were practically nil in cafeteria-diet fed rats compared with controls; there was no effect of sex. Conclusions. RBC membrane glycosylation is a sensitive indicator of developing metabolic syndrome-related hyperglycemia, more sensitive than the general measurement of plasma or RBC protein glycosylation. The extensive glycosylation of blood proteins does not seem to be markedly affected by sex; and could be hardly justified from an assumedly sustained plasma hyperglycemia. The low levels of glucose found within RBC, especially in rats under the cafeteria diet, could hardly justify the extensive glycosylation of hemoglobin and the lack of differences with controls, which contained sizeable levels of intracellular glucose. Additional studies are needed to study the dynamics of glucose in vivo in the RBC to understand how such extensive protein glycosylation could take place.