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The Role of Pregnancy-Associated Hormones in the Development and Function of Regulatory B Cells
(2014)
During mammalian pregnancy, highly specialized mechanisms of immune tolerance are triggered in order to allow the semi-allogeneic fetus to grow within the maternal uterus in harmony with the maternal immune system. Among other mechanisms, changes in the endocrine status have been proposed to be at least part of the machinery responsible for the induction of immune tolerance during pregnancy. Indeed, pregnancy-associated hormones, estradiol, progesterone, and human chorionic gonadotropin are known to confer immune suppressive capacity to innate as well as adaptive immune cells. Regulatory B cells, a subpopulation of B lymphocytes with strong immunosuppressive functions, were shown to expand during pregnancy. Furthermore, it is well-known that some women suffering from multiple sclerosis, significantly improve their symptoms during pregnancy and this was attributed to the effect of female sex hormones. Accordingly, estradiol protects mice from developing experimental autoimmune encephalomyelitis by triggering the expansion and activation of regulatory B cells. In this review, we discuss different mechanisms associated with the development, activation, and function of regulatory B cells with a special focus on those involving pregnancy-associated hormones.
Ziel: Das Ziel der Studie ist es, den Zusammenhang von maternalem Diabetes und fetalem und maternalem Schwangerschaftsoutcome zu beschreiben. Methode: Insgesamt wurden n=4593 Mütter und ihre Kinder in der populationsbasierten SNiP Studie, Survey of Neonates in Pomerania eingeschlossen. Die Datenerhebung erfolgte im Zeitraum vom 05/2002 – 11/2008 in Universitäts- und Kreiskrankenhäusern im Nordosten von Mecklenburg-Vorpommern durch face-to-face Interviews, Fragebögen und Einsicht in die Krankenakten und Labordaten. Der Vergleich erfolgte zwischen Diabetes-erkrankten Müttern mit präexistenter oder sich erstmanifestierender Blutglukoseintoleranz (n=243), die klinisch an Hand des oralen Glukosetoleranztest diagnostiziert sind und Non-Diabetes-erkrankten Müttern (n=4350). Ergebnisse: Die Prävalenz für eine maternale Blutglukoseintoleranz beträgt 5,3%. Als Komorbiditäten mit der maternalen Blutglukoseintoleranz sind ein höheres Alter, eine höhere Anzahl von vorausgegangenen Schwangerschaften (Parität der Mutter) und Übergewichtigkeit (Relative Risiko 1,97) assoziiert. Als fetale Risikoparameter kann eine gehäufte Makrosomie (OR=2,28) aufgezeigt werden. Als maternaler Risikoparameter zeigt sich ein gehäuft positiver Nachweis vaginaler Erreger (OR=1,97). Als negativer Outcome zeigt sich eine insgesamt gesteigerte Sectiorate und Einsatz geburtsmechanischer unterstützender Maßnahmen (OR=1,96) und eine Häufung pathologischer Geburtslagen (15,3%Diabetes/9,3%kein Diabetes) beim Kind, sowie ein nahezu viermal so hohes Risiko einer postnatalen stationären Aufnahme des Neugeborenen (OR=3,70) und Notwendigkeit einer präpartalen ärztlichen Behandlung (OR=4,78) bei der Mutter mit diabetischer Stoffwechsellage. Bei einem Drittel (32,2%) der Neugeborenen diabetischer Mütter findet sich eine Hypoglykämie gegenüber 2,3% der übrigen Neugeborenen. Trotz erhöhter Sectio-Rate findet sich keine erhöhte Inzidenz von Atemstörungen bei den Neugeborenen diabetischer Mütter. Keine Unterschiede finden sich beim Apgar, arteriellen Nabelschnur-pH und der Inzidenz einer Hyperbilirubinämie. Fazit: In der SNiP-Kohorte liegt die Prävalenz des Diabetes in der Schwangerschaft klar im oberen Bereich der in der Literatur berichteten Häufigkeiten. Der Gestationsdiabetes ist mit erhöhten Raten pathologischer Geburtslagen, Kaiserschnittentbindungen und neonataler Makrosomie assoziiert. Das Risiko für eine stationäre Behandlung ist für das Neugeborene einer diabetischen Mutter um den Faktor 4 erhöht. Die Hauptursache liegt in dem Auftreten neonataler Hypoglykämien bei einem Drittel dieser Kinder. Diese Ergebnisse zeigen, dass der Diabetes in der Schwangerschaft weiterhin, auch bei verbesserter Therapie und Überwachung, eine relevante Risikoerhöhung für Mutter und Kind mit sich bringt.
Interleukin-33 (IL-33) is a mucosal alarmin belonging to the IL-1 cytokine family and is now recognized to have a key role in innate and adaptive immunity, contributing to tissue homeostasis and response to environmental stresses. In addition, IL-33 has also been shown to work as a positive regulator that initiates and maintains a Th2 immune response. In the context of pregnancy, it has been recently demonstrated that upon certain stress conditions, such as an infection induced inflammation, IL-33 is released from the uterine mucosa and triggers decidual B cells to produce anti-inflammatory molecules, which in turn restore immune homeostasis and prevents the development of preterm birth. In this study we therefore performed a detailed characterization of IL-33 receptor (Il1rl1 or ST2) expression in B cells during normal pregnancy, as well as in a mouse model of preterm birth. We observed that splenic B cells significantly up-regulate the expression of Il1rl1 during pregnancy and identified the B1 B cell population as the main ST2-expressing B cell subset. A further kinetic analysis showed that percentages of ST2-expressing B1 B cells are significantly augmented on days 12 and 14 of pregnancy, both in the spleen and peritoneal cavity of pregnant mice, and then drop toward the end of pregnancy to the levels observed in non-pregnant animals. Furthermore, using a mouse model of LPS-induced preterm birth, we demonstrated that not only are the percentages of ST2-expressing B1 B cells significantly enlarged in the spleen during the acute phase of preterm birth, but decidual B cells also significantly up-regulate ST2 expression as compared to term-pregnant mice. Overall, our results suggest a functional role of ST2 expression in B cells during pregnancy and reinforce the importance of the IL-33/ST2 axis in B cells as a critical mechanism to control inflammation-induced preterm birth.
Colonic atresia (CA) is a rare disease with an incidence range between one of 20 000 and one of 66 000 live births. Most CA are located within the proximal colon; distal CA are even rarer. Because of its rarity, another case shall be described herewith. A 37th week of pregnancy born child was noticed occurring multiple vomiting, a distended abdomen and additional whitish-bloody stool shortly thereafter. In the first operation, a double-barrel stoma was created. After sufficient weight gain and alignment of the stoma ends, a secondary anastomosis was created in the child after 2 months. The diagnosis can be made reliably on the basis of an X-ray and leads to a good outcome with prompt surgical intervention. However, accompanying malformations should always be considered.
During pregnancy, the maternal immune system faces a double dilemma: tolerate the growing semi-allogeneic fetus and at the same time protect the mother and the progeny against pathogens. This requires a fine and extremely regulated equilibrium between immune activation and tolerance. As professional antigen presenting cells, B cells and in particular B-1a B cells, can activate or tolerize T cells and thus participate in the generation or regulation of the immune response. B-1a B cells were involved in the humoral immune response leading to pre-eclampsia, one of the main medical complications during pregnancy. Here we demonstrated that B-1a B cells are additionally involved in cellular immune mechanisms associated with pregnancy complications. Using a mouse model of pregnancy disturbances, we showed that B-1a B cells from animals suffering pregnancy disturbances but not from those developing normal pregnancies induce the differentiation of naïve T cells into Th17 and Th1 cells. This differential role of B-1a B cells during pregnancy seems to be associated with the co-stimulatory molecule CD86 as normal pregnant mice showed lower percentages of CD86 expressing B-1a B cells as compared to pregnant mice developing pregnancy disturbances or to non-pregnant animals. Our data bring to light a new and not explored role of B-1a B cells in the context of pregnancy.
Introduction:
The amniotic fluid – as the medium surrounding the fetus, it is holding a crucial role in the maintenance and development of a successful pregnancy. While providing mechanical protection to the fetus, it also offers considerable immunological defense. In fact, it is known that the amniotic fluid plays a significant role in the innate immune system, as many of its corresponding substances show substantial antimicrobial function. Also, components of the adaptive immune system, including B cells, have been described within the amniotic fluid. An increase of immune cells in the amniotic fluid in cases of intra-amniotic infection indicates their involvement in inflammation-related pathologies of pregnancy. However, especially B cells in the amniotic fluid have not yet been thoroughly investigated.
The aim of this work is a deeper examination of the B-lymphocytes within the amniotic fluid. Based on the analysis of surface molecules this includes their phenotype, origin and func-tion. In the long term this could substantiate our understanding of intraamniotic inflammation and or infection, which are casually linked with preterm birth, fetal inflammatory response syndrome and fetal morbidity.
This, in turn, could pave the way for potential diagnostic methods and treatments.
Methods:
For all experiments 8-12-weeks-old pregnant mice were sacrificed at day 14 of pregnancy. The amniotic fluid was collected and specific cell subsets were isolated using MACS cell separation. Cells were then co-cultured with a bone marrow stromal cell line and stimulated in vitro.
The analysis of the population distribution and cytokine production was performed by flow cytometry. To analyze IgM-levels in the supernatant of the co culture, ELISA was used. Statistical analysis was performed using GraphPad Prism software.
Results:
The amniotic fluid contains different developmental stages of B cells, which most likely are of fetal origin. This is supported by the expression of paternal surface markers. An extensive proliferation and switch towards a more mature phenotype upon co-culture shows that the immature subsets of amniotic fluid B cells are able to expand and mature in vitro. Amniotic
fluid B cells spontaneously produce IgM and show functional adaption upon in vitro stimula-tion as evidenced by the increase of cell activation markers.
Conclusion:
For the first time a deep investigation of B-cells within the amniotic fluid was performed, covering phenotype and cell functionality. This work shows that there is a B cell compartment within the amniotic fluid, which, to a certain extent, is able to mature and gain functionality when exposed to external stimuli. This supports the hypothesis of the amniotic fluid as crucial immunological line of defense against inflammatory and infectious challenges during pregnancy.
Background. The German maternity guidelines require regular medical checkup (MC) during pregnancy as a measure of prevention. Socioeconomic factors such as education, profession, income and origin, but also age and parity may influence the preventive and health behavior of pregnant women. The aim was to investigate the influence of these factors on the participation rate in MC of pregnant women. Method. The current analysis is based on the prospective population-based birth cohort study Survey of Neonates in Pomerania, which was conducted in Western Pomerania, Germany. The data of 4092 pregnant women from 2004 to 2008 were analyzed regarding the antenatal care and health behavior. Up to 12 MC were regularly offered; participation in 10 MC is defined as standard screening according to maternity guidelines. Results. Women participated in the first preventive MC on average in the 10th (±3.8 SD) week of pregnancy. 1343 (34.2%) women participated in standard screening and 2039 (51.9%) took a screening above standard. 547 (13.92%) women participated in less than the 10 standard MCs. In addition, about one-third of the pregnancies investigated in this study were unplanned. Bivariate analyses showed an association between better antenatal care behavior and higher maternal age, stabile partnerships and mother born in Germany, p < 0.05. On the contrary antenatal care below standard were more often found by women with unplanned pregnancies, less educational women and women with lower equivalent income, p < 0.001. Health behaviors also influenced antenatal care. Whereas the risk of antenatal care below standard increased by smoking during pregnancy (RRR 1.64; 95% CI 1.25, 2.14) and alcohol consumption (RRR 1.31; 95% CI 1.01, 1.69), supplementation intake was associated with decreased risk (iodine—RRR 0.66; 95% CI 0.53, 0.81; folic acid—RRR 0.56; 95% CI 0.44, 0.72). The health behavior of pregnant women also differs according to their social status. Higher maternal income was negatively correlated with smoking during pregnancy (OR 0.2; 95% CI 0.15, 0.24), but positively associated with alcohol consumption during pregnancy (OR 1.3; 95% CI 1.15, 1.48) and lower pre-pregnancy BMI (Coef. = 0.083, p < 0.001). Lower maternal education was positively correlated with smoking during pregnancy (OR 59.0; 95% CI 28.68, 121.23). Conclusions. Prenatal care according to maternity guidelines is well established with a high participation rate in MC during pregnancy of more than 85%. However, targeted preventive measures may address younger age, socioeconomic status and health-damaging behaviors (smoking, drinking) of the pregnant women because these factors were associated with antenatal care below standard.
Ziel:
Diese populationsbasierte Studie untersucht sowohl die Prävalenz adipöser Schwangerer und deren Geburtsoutcome als auch den Einfluss der Adipositas auf das Outcome des Neugeborenen. Sie beschreibt die Bedeutung der Gewichtsentwicklung in der Schwangerschaft für Mutter und Kind.
Material/Methode:
Insgesamt wurden n=4593 Mütter und ihre Kinder in der populationsbasierten SNiP Studie, Survey of Neonates in Pomerania untersucht. Die Datenerhebung erfolgte im Zeitraum von März 2003 bis November 2008 in Universitäts- und Kreiskrankenhäusern im Nordosten von Mecklenburg-Vorpommern nach standardisierten Fragebögen, Erhebung von Laborparametern und klinischer Dokumentationen. Zur Beurteilung der Schwangerschaftskomplikationen und des Schwangerschaftsausganges wurden die Schwangeren in einzelne BMI Gruppen eingeteilt. Die individuelle Gewichtzunahme wurde ermittelt. Als Outcomeparameter wurden prä- und perinatale Erkrankungen, Pathologien und Risiken bei der Schwangeren und dem Neugeborenen ermittelt und ausgewertet. Hierbei wurden auch sozioökonomischen Faktoren erhoben und ausgewertet.
Ergebnis:
Adipositas ist eine Volkskrankheit. Die mit dieser Volkskrankheit im Zusammenhang stehenden gesundheitlichen Risiken treten nicht nur im Alter auf, sondern es entstehen auch zunehmend Gefährdungen junger Menschen. Hier sind besonders schwangere Frauen mit ihren Neugeborenen betroffen. Mehr als ¼ der schwangeren Frauen im Studiengebiet OVP sind präadipös (BMI 25-29,9) oder adipös (BMI ≥ 30).
Adipöse Schwangere finden sich dem weltweiten Trend entsprechend in der unteren sozialen Bevölkerungsschicht.
Eine Adipositas der Mutter beinhaltet Risiken für Mutter und Kind. Das Risiko einer adipösen Mutter (BMI ≥ 30) an einem Gestationsdiabetes zu erkranken gegenüber einer normalgewichtigen Mutter (BMI 19-24,9) steigt auf das 4,5fache. Das Risiko, eine Gestose auszubilden, steigt auf das 3fache.
Das Risiko des Auftretens mehr als einer Schwangerschaftskomplikation verdoppelt sich bei adipösen Müttern gegenüber normalgewichtigen Müttern. Dies kann unter der Geburt zu höheren Komplikationsraten führen. Häufiger ist bei adipösen Müttern eine primäre oder sekundäre Sectio indiziert. Für die Mütter beinhaltet eine Sectio die allgemeinen Risiken einer Operation (Thrombose/Embolie- Risiko, Blutungen, Wundinfektionen und Bildungen von Verwachsungen) bis hin zur Unfruchtbarkeit.
Zusätzlich stellt sich negativ heraus, dass die Fruchtwasserqualität mit zunehmender Adipositas schlechter wird. Es zeigt sich häufiger Mekonium im Fruchtwasser als Ausdruck einer Hypoxie mit Hyperperistaltik des kindlichen Darms. Durch die Sauerstoffunterernährung kann es vor oder während der Geburt zur Meconiumaspiration kommen, die Obstruktionen und chemische Schädigungen der Lunge verursachen können.
Bei der Betrachtung der Ergebnisse stellt sich allerdings immer wieder heraus, dass die Gewichtszunahme während der Schwangerschaft bei der Beurteilung des Geburtsoutcomes eine untergeordnete Rolle spielt. Allenfalls ist sie ein Parameter zur Abschätzung der Körpermaße des Kindes.
Der BMI eignet sich besser zur Abwägung von Risiken für Mutter und Kind.
Zuletzt ist zu vermerken:
Dennoch sollten untergewichtige Frauen auch nicht außer Acht gelassen werden.
Untergewichtige Frauen haben häufiger Fehlgeburten oder gebären häufiger Frühgeborene mit fehlenden Reifezeichen.
Schlussfolgerung:
Schwangerschaften von adipösen Schwangeren sind mit deutlich erhöhten prä- und perinatalen Schwangerschaftsrisiken für Mutter und Kind behaftet. Daher ist es sinnvoll, schon frühzeitig (am besten vor der Schwangerschaft bei Kinderwunsch) die werdende Mutter bei bestehender Disposition über die Folgen einer Adipositas aufzuklären und durch geeignete Maßnahmen (Diätberatung, Ernährungsumstellung) der Adipositas entgegen zu wirken. Die Beratung sollte jedoch nicht mit der Geburt des Kindes enden. So sollte nach der Geburt das Stillen des Kindes für einen gewissen Zeitraum empfohlen werden, um das spätere Adipositasrisiko des Neugeborenen zu verringern.
Der soziale Status spielt bei der Bekämpfung der Adipositas eine besondere Rolle.
Bildung kann zu einem großen Teil das Auftreten von Adipositas vermeiden.
For the normal development of pregnancy, a balance between immune tolerance and defense is crucial. However, the mechanisms mediating such a balance are not fully understood. CD83 is a transmembrane protein whose expression has been linked to anti-inflammatory functions of T and B cells. The soluble form of CD83, released by cleavage of the membrane-bound protein, has strong anti-inflammatory properties and was successfully tested in different mouse models. It is assumed that this molecule contributes to the establishment of immune tolerance. Therefore, we postulated that the expression of CD83 is crucial for immune tolerance during pregnancy in mice. Here, we demonstrated that the membrane-bound form of CD83 was upregulated in T and B cells during allogeneic murine pregnancies. An upregulation was also evident in the main splenic B cell subtypes: marginal zone, follicular zone, and transitional B cells. We also showed that there was an augmentation in the number of CD83+ cells toward the end of pregnancy within splenic B and CD4+ T cells, while CD83+ dendritic cells were reduced in spleen and inguinal lymph nodes of pregnant mice. Additionally, B lymphocytes in late-pregnancy presented a markedly higher sensitivity to LPS in terms of CD83 expression and sCD83 release. Progesterone induced a dosis-dependent upregulation of CD83 on T cells. Our data suggest that the regulation of CD83 expression represents a novel pathway of fetal tolerance and protection against inflammatory threats during pregnancy.