Galectin-10 Expression in Placentas of Women with Gestational Diabetes.

Galectins are known to play an important role in immunoregulatory processes and autoimmune diseases. Galectin-10 is a cytoplasmic protein of human eosinophils and is involved in various eosinophilic diseases. Since increased galectin expression is already detected in the placentas of mothers with gestational diabetes mellitus (GDM), this study focuses on the specific role of galectin-10 and hints at consequences for the diagnosis and therapeutic options of GDM. It is hypothesized that the difference in galectin-10 expression will raise the pathophysiological understanding of gestational diabetes. The study population consists of 80 women: 40 healthy mothers and 40 women suffering from gestational diabetes mellitus. The expression of galectin-10 was analyzed in the syncytiotrophoblast (SCT) and the decidua of the placenta via immunohistochemistry and immunofluorescence double staining. The immunoreactivity score (IRS) was used for evaluation. The results in this study were significant for an overexpression of galectin-10 in GDM placentas compared with the control group. The syncytiotrophoblast showed overexpression in the nucleus and the cytoplasm, whereas expression of galectin-10 in the decidua was significant in the cytoplasm only. This study identified the expression changes in galectin-10 in placental tissue between healthy and GDM mothers and intensified the understanding of gestational diabetes. Assuming that gestational diabetes mellitus is involved in inflammatory processes, galectin-10 might play a role in the development and maintenance of GDM. Further investigation is required to strengthen these findings.

Placental Galectin-2 Expression in Gestational Diabetes: A Systematic, Histological Analysis.

Gestational diabetes mellitus (GDM) is the most common pregnancy-associated metabolic disorder that negatively impacts on the health of both mothers and their offspring in the long-term. The molecular mechanisms involved are not fully understood. As in other states of insulin resistance, a disproportionate immune response in GDM leads to a state of chronic low-grade inflammation. Galectin-2 exerts regulatory effects on different immune cells. This study investigated galectin-2 expression in the placenta of 40 GDM patients and 40 controls, in a sex-specific manner. Immunohistochemistry was used for semi-quantitative analysis of expression strength. The phenotypes of galectin-2 expressing cells were characterized through double immunofluorescence. We found a significant up-regulation of galectin-2 in the fetal syncytiotrophoblast, as well as in the maternal decidua of GDM placentas. Double staining showed a strong galectin-2 expression in extra villous trophoblast cells and fetal endothelial cells in GDM. These findings present the first systematic investigation of galectin-2 in GDM. The findings contribute to the emerging understanding of the role of immunomodulation and inflammation in GDM and of galectin-2 itself. This might also have implications for the long-term cardiovascular health of the offspring.

Prototype and Chimera-Type Galectins in Placentas with Spontaneous and Recurrent Miscarriages.

Galectins are galactose binding proteins and, in addition, factors for a wide range of pathologies in pregnancy. We have analyzed the expression of prototype (gal-1, -2, -7, -10) and chimera-type (gal-3) galectins in the placenta in cases of spontaneous abortions (SPA) and recurrent abortions (RA) in the first trimester. Fifteen placental samples from healthy pregnancies were used as a control group. Nine placentas were examined for spontaneous abortions, and 12 placentas for recurrent abortions. For differentiation and evaluation of different cell types of galectin-expression in the decidua, immunofluorescence was used. For all investigated prototype galectins (gal-1, -2, -7, -10) in SPA and RA placenta trophoblast cells the expression is significantly decreased. In the decidua/extravillous trophoblast only gal-2 expression was significantly lowered, which could be connected to its role in angiogenesis. In trophoblasts in first-trimester placentas and in cases of SPA and RA, prototype galectins are altered in the same way. We suspect prototype galectins have a similar function in placental tissue because of their common biochemical structure. Expression of galectin 3 as a chimera type galectin was not found to be significantly altered in abortive placentas.

Getting too sweet: galectin-1 dysregulation in gestational diabetes mellitus.

Galectin-1 (gal-1) is a prototype carbohydrate-binding protein, whose dysregulation is associated with adverse pregnancy outcomes such as spontaneous abortion and pre-eclampsia. Furthermore, it is known that faulty gal-1 protein production or gene regulation can be caused by single-nucleotide polymorphisms in the LGALS1 gene. Gestational diabetes mellitus (GDM) is also an adverse pregnancy outcome and the most common metabolic disorder during gestation. However, gal-1 expression patterns during GDM remain largely unknown. Our aims were to define local and peripheral gal-1 expression patterns during pregnancy, and to investigate LGALS1 gene polymorphisms in GDM patients. Circulating gal-1 levels were determined by ELISA in GDM patients and normal pregnant controls, and LGALS1 gene polymorphisms were assessed for association with GDM. Placental tissues were collected from control and GDM term pregnancies to evaluate local gal-1 expression by immunofluorescence. Our results show that GDM is associated with a failure to increase circulating gal-1 levels during the second and third trimester, as well as overexpression of gal-1 in placental tissue. Additionally, the LGALS1 polymorphism rs4820294 was associated with the development of GDM. In pregnancies complicated by GDM, we observed gal-1 dysregulation both locally in the placenta and peripherally in the circulation. Furthermore, the association between the LGALS1 polymorphism and GDM may indicate a genetic contribution to this adverse pregnancy outcome.

Placental expression of inflammatory Galectin-12 is associated with gestational diabetes.

OBJECTIVES: Gestational diabetes mellitus (GDM) is a growing health concern. Since members of the galectin-family are identified to play a role in the pathogenesis of GDM, we determined galectin-12 as an essential protein due to its influence in lipolysis and inflammation processes. This study investigates the expression of galectin-12 in the placentas of women with GDM. STUDY DESIGN: The study population includes 40 expectant women suffering from GDM and 40 healthy controls. The expression of galectin-12 in the syncytiotrophoblast (SCT) and the extra villous trophoblast (EVT) of the placenta was analyzed by immunohistological staining and double immunofluorescence. Immunoreactivity Score (IRS) was used for evaluation. RESULTS: The results demonstrate a significant overexpression of galectin-12 in the nucleus of the SCT and the EVT of placentas with GDM compared to the healthy control group. Additionally, double immunofluorescence visualizes corresponding results with an overexpression of galectin-12 in the extra villous trophoblast of GDM placentas representing maternal cells. CONCLUSION: This study identifies galectin-12 to be associated with the process of gestational diabetes mellitus. These findings are in correspondence with the involvement of galectin-12 in inflammatory processes. Maternal BMI and male sex seem to be confounder for the expression of galectin-12 in the nuclear syncytiotrophoblast, but not in other parts of the investigated placental areas. Further investigations are necessary to verify the correlation between gestational diabetes mellitus and the expression of galectin-12 in the placenta and to further elucidate its distinct role.

Overexpression of galectin-4 in placentas of women with gestational diabetes.

OBJECTIVE: Galectins are known for their immunomodulatory functions in placentas. They are associated with pregnancy disorders such as preeclampsia, HELLP-Syndrome and intrauterine growth restriction (IUGR). In addition, galectins seem to be overexpressed in placentas of women with gestational diabetes mellitus (GDM). STUDY DESIGN: The collective consisted of 40 women diagnosed with GDM and 40 healthy expectant mothers. The expression of Gal-4 was investigated in syncytiotrophoblast (SCT), representing the fetal part of the placenta, and decidual tissues, representing the maternal part of the placenta, by immunohistochemistry and immunofluorescence double staining. Expression levels were evaluated using the immunoreactive score (IRS). RESULTS: Nuclear IRS of Gal-4 is significantly higher in SCT cells of placentas of expectant mothers diagnosed with GDM. Overexpression of Gal-4 observed in the decidua of women with GDM by significant higher nuclear and cytoplasmatic IRS of Gal-4. Multivariate regression showed that Gal-4 is significantly overexpressed in the nucleus of SCTs and cytoplasm of decidual cells of placentas with GDM. GDM could be identified as a significant predictor for both cases. CONCLUSION: The results of this study provide further evidence for the involvement of galectins in the processes of chronic inflammation throughout a pregnancy with GDM. These findings are also in line with the known overexpression of galectin-1 in placental tissues of GDM women. Further evaluation of the role of galectins in this process is warranted.

Comparative analyses on expression of galectins1-4, 7-10 and 12 in first trimester placenta, decidua and isolated trophoblast cells in vitro.

INTRODUCTION: Galectins are members of the mammalian ß-galactoside-binding proteins, which recognize Galß1-4GlcNAc sequences of several cell surface oligosaccharides. Plenty of galectins are already described in human tissue, especially in placenta. Here, gal-1-4, 7-10 and gal-12 were investigated systematically in trophoblast and decidua cells of first trimester placentas. MATERIAL AND METHODS: Within this study, 15 first trimester placentas after induced abortion (7th-14th week of gestation) were examined with immunohistology and immunofluorescence based on a scoring system. Moreover, isolated and cultivated trophoblast cells from the first trimester were analyzed and evaluated for expression of gal-1-4, gal-7-10 and gal-12 at mRNA and protein level with real-time RT-Polymerase chain Reaction/PCR (Taq-Man). Double immunofluorescence with trophoblast specific markers identified galectin expressing cells at the feto-maternal interface. RESULTS: We could detect immunohistochemical staining of galectins 1-4, 7-10 and 12 in first trimester placenta: all examined galectins were found in the cytotrophoblast (CTB) and syncytiotrophoblast (SCT). Gal-1, -2, -3, -4, -7, -8, -9, -10 and -12 were identified in extravillous trophoblast cells (EVT) in immunohistology and immunoflourescence. The expression of gal-1, -9, -10, and gal-12 increased after 96h incubation in vitro without stimulation at mRNA level, while gal-2, -3, -4, -7 and -8 were decreased. DISCUSSION AND CONCLUSION: This study describes a systematic analysis of the expression of gal-1-4, gal-7-10 and gal-12 in first trimester placentas and isolated trophoblast cells. Expression levels at mRNA level and the change within 96h cultivation in vitro indicate a possible influence on syncytium building of trophoblast cell on expression of galectins. Therefore, an interaction of galectins in vitro in syncytium building is possible.

Involvement of galectin-1 in reproduction: past, present and future.

BACKGROUND: After recognition of its pivotal contribution to fetomaternal tolerance, the study of galectin-1 (gal-1) functions in the context of pregnancy became an attractive topic in reproductive medicine. Despite considerable advances in the understanding of the immuno- and growth-regulatory properties of gal-1 at the fetal-maternal interface, many functional aspects of this lectin in reproduction are only emerging. METHODS: The published literature was searched using Pubmed focusing on gal-1 signalling and functional properties at the maternal-fetal interface, including data on its implication in pregnancy disorders and malignancies of the female reproductive system. Papers discussing animal and human studies were included. RESULTS: This review provides an overview of gal-1 functions during pregnancy, such as modulation of maternal immune responses and roles in embryo implantation and placentation. We also emphasize the role of gal-1 in key regulatory processes, including trophoblast migration, invasion, syncytium formation and expression of non-classical MHC class I molecules (HLA-G). In addition, we argue in favour of gal-1 pro-angiogenic properties, as observed in tumourigenesis and other pathological settings, and its implication in the angiogenesis process associated with early gestation. CONCLUSION: The involvement of gal-1 in the regulation of different processes during the establishment, development and maintenance of pregnancy could be described as unique. Gal-1 has emerged as an important lectin with major functions in pregnancy.