Petra C. Arck

Depletion of CD8+ cells abolishes the pregnancy protective effect of progesterone substitution with dydrogesterone in mice by altering the Th1/Th2 cytokine profile

One of the most remarkable immunological regulations is the maternal immune tolerance toward the fetal semiallograft during pregnancy, which has been referred to as immunity’s pregnant pause. Rejection of the semiallogeneic trophoblast cells must be selectively inhibited and pathways presumably include Th2 cytokines unopposed by Th1 cytokines. Steroid hormones, including progesterone, have similar effects. Low levels of progesterone and Th2 cytokines and high levels of Th1 cytokines are attributable for increased abortions in mammalians, which may be triggered by psychoemotional stress. Thus, the aim of the present study was to provide experimental evidence for the mechanism involved in the mediation of immune responses by endocrine signals during pregnancy and stress-triggered pregnancy failure. DBA/2J-mated CBA/J female mice were randomized in three groups: 1) control females, 2) mice exposed to stress on gestation day 5.5, and 3) mice exposed to stress and substituted with dydrogesterone, a progestogen with a binding profile highly selective for the progesterone receptor on gestation day 5.5. On gestation days 7.5, 9.5, and 10.5, mice of each group were sacrificed, and the frequency of CD8+ cells and cytokine expression (IL-4, IL-12, TNF-α, IFN-γ) in blood and uterus cells was evaluated by flow cytometry. Additionally, some mice were depleted of CD8 cells by injection of mAb. We observed that progesterone substitution abrogated the abortogenic effects of stress exposure by decreasing the frequency of abortogenic cytokines. This pathway was exceedingly CD8-dependent, because depletion of CD8 led to a termination of the pregnancy protective effect of progesterone substitution.

Stress Inhibits Hair Growth in Mice by Induction of Premature Catagen Development and Deleterious Perifollicular Inflammatory Events via Neuropeptide Substance P-Dependent Pathways

It has been much disputed whether or not stress can cause hair loss (telogen effluvium) in a clinically relevant manner. Despite the paramount psychosocial importance of hair in human society, this central, yet enigmatic and controversial problem of clinically applied stress research has not been systematically studied in appropriate animal models. We now show that psychoemotional stress indeed alters actual hair follicle (HF) cycling in vivo, ie, prematurely terminates the normal duration of active hair growth (anagen) in mice. Further, inflammatory events deleterious to the HF are present in the HF environment of stressed mice (perifollicular macrophage cluster, excessive mast cell activation). This provides the first solid pathophysiological mechanism for how stress may actually cause telogen effluvium, ie, by hair cycle manipulation and neuroimmunological events that combine to terminate anagen. Furthermore, we show that most of these hair growth-inhibitory effects of stress can be reproduced by the proteotypic stress-related neuropeptide substance P in nonstressed mice, and can be counteracted effectively by co-administration of a specific substance P receptor antagonist in stressed mice. This offers the first convincing rationale how stress-induced hair loss in men may be pharmacologically managed effectively.

Lineage, maturity, and phenotype of uterine murine dendritic cells throughout gestation indicate a protective role in maintaining pregnancy.

Abstract Dendritic cells (DCs) are known to play a major role in the induction, maintenance, and regulation of immune responses. Recently, DCs have been described to be present at the feto-maternal interface in human decidua. However, only limited information is available about DC presence, phenotype, and—more importantly—function throughout gestation. Thus, we analyzed local (uterine) and systemic (blood) DCs in a murine model. DBA/2J mated CBA/J females with vaginal plugs were separated and killed on Gestation Days (GDs) 1.5, 3.5, 5.5, 6.5, 7.5, 8.5, 10.5, 13.5, 15.5, or 17.5. Frequency of uterine and blood CD11c+ DC, phenotype (coexpression of CD8α and major histocompatibility complex class II [MHC II] antigens), and presence of intracellular cytokines (interleukins 12 and 10) were determined by flow cytometry. The morphology of DC in the pregnant uterus was evaluated by immunohistochemistry. In uterus, the relative number of CD11c+ cells increased from GD 5.5, reaching a plateau on GD 9.5 until GD 17.5, while a transient peak of systemic CD11c+ cells was found on GD 8.5 and 10.5. The vast majority of uterine DCs were CD8α− and thus, belonged to the myeloid lineage. Interestingly, a significant peak of lymphoid DC was present on GD 1.5 and 5.5. Further, significantly more intracellular interleukin 10 than interleukin 12 was present in CD11c+ cells. Interestingly, mature DCs (MHC II+) were diminished from GD 5.5 to 8.5. Characterization of CD11c+ cell kinetics in uterus and blood reveals variation of phenotype during pregnancy, pointing toward an eminent immunoregulatory role of DCs throughout gestation at the feto-maternal interface.

The progesterone derivative dydrogesterone abrogates murine stress-triggered abortion by inducing a Th2 biased local immune response

Stress is known to induce abortions in mice and humans, putatively via increased levels of abortogenic Th1 cytokines and a decrease of progesterone. Adequate levels of progesterone exert an antiabortive response through binding to the progesterone-receptor, which induces the release of progesterone-induced blocking factor (PIBF) from lymphocytes. PIBF is highly pregnancy-protective by induction of a Th2 biased immune activity. The aim of this study was to investigate the effect of the progesterone derivative dydrogesterone (6-dehydro-retroprogesterone) in stress-triggered murine abortion. DBA/2J-mated CBA/J female mice were randomized in different groups: two groups were treated with different dydrogesterone dosages in a single injection before exposure to sound stress on Day 5 of pregnancy, one group was exposed to stress without dydrogesterone treatment, the fourth group received no stress and no dydrogesterone. On gestation Day 13, a highly elevated abortion rate was detected in stressed mice compared to control mice. Stressed animals presented lower levels of progesterone and PIBF in plasma and a reduced staining intensity of progesterone receptor at the feto-maternal interface. Injection of dydrogesterone abrogated the effect of stress on the abortion rate. Further, dydrogesterone increased levels of plasma PIBF in stressed mice, but did not affect progesterone levels. Interestingly, dydrogesterone dramatically increased the percentage of IL-4 positive decidual immune cells in stressed mice. Our data suggest that dydrogesterone abrogates stress-triggered abortion by inducing a Th2 biased local immune response.

Stress and pregnancy loss: role of immune mediators, hormones and neurotransmitters.

This review highlights recent studies investigating the impact of stress on pregnancy health or loss. Spontaneous abortion is the most common adverse pregnancy outcome, and stress has been suggested to be abortogenic in mice and humans. A wealth of information has been published on the effect of stress on the nervous, endocrine and immune systems during the past two decades. Stress‐ and/or pregnancy‐related hormones (corticotropin releasing hormone, adrenocorticotropin, prolactin, and progesterone) might interact with peripheral and local immuncompetent cells, such as certain T cell subsets, mast cells or NK cells, and result in changes of cytokine production. Since a well‐balanced interaction of nervous, endocrine and immune system is crucial for the maintenance of successful pregnancy, putative mechanisms and recent observations on stress‐triggered pregnancy failure have been reviewed.

Heme oxygenases in pregnancy II: HO-2 is downregulated in human pathologic pregnancies.

Problem:  We previously reported a diminished expression of the heme‐degrading enzymes heme oxygenases (HO)‐1 and HO‐2 in decidua and placenta from mice undergoing Th1‐mediated abortion, strongly indicating the protective effect of HO in murine pregnancy maintenance. Here we investigated whether the expression of HO‐1 and HO‐2 is also reduced at the feto‐maternal interface of pathologic human pregnancies.

Introducing a mouse model for pre-eclampsia: adoptive transfer of activated Th1 cells leads to pre-eclampsia-like symptoms exclusively in pregnant mice

Pre‐eclampsia (PE) is the most severe pregnancy‐related disease, leading to high maternal and fetal morbidity/mortality. Immunological imbalances associated with endothelial cell dysfunction have been hypothesized as a cause for the onset and perpetuation of PE. Valid and reliable animal models are urgently required to test this hypothesis and to better understand the mechanisms underlying PE. We developed a novel PE‐model by adoptively transferring activated BALB/c Th1‐like splenocytes into allogeneically pregnant BALB/c female mice during late gestation; the model mimicked the symptoms of PE, i.e. increased blood pressure and glomerulonephritis accompanied by proteinuria. Interestingly, these PE‐like symptoms were not detectable in non‐pregnant recipients of activated Th1‐like cells. Adoptive cell transfer adversely affected the outcome of pregnancy by increasing fetal rejection, with uterine immune cells showing an inflammatory profile. In conclusion, we have established a valid and reliable PE mouse model, which opens vast opportunities for therapeutic interventions.

Questioning the Th1/Th2 Paradigm in Reproduction: Peripheral Levels of IL-12 are Down-Regulated in Miscarriage Patients

Zenclussen AC, Fest S, Busse P, Joachim R, Klapp BF, Arck PC. Questioning the Th1/Th2 paradigm in reproduction: peripheral levels of IL‐12 are down‐regulated in miscarriage patients. AJRI 2002; 48:245–251

Murine stress-triggered abortion is mediated by increase of CD8+ TNF-α+ decidual cells via substance P

PROBLEM: Stress is known to induce abortions in mice and humans. Increased levels of abortogenic type 1 helper T‐cell cytokines and decreased levels of pregnancy protective cytokines could be linked to stress‐triggered embryonic loss. Stress promotes neurotransmitter substance P (SP) release in tissues. SP increases the production of decidual tumor necrosis factor (TNF)‐α, whereby the phenotype of these TNF‐α‐producing cells is hypothetical. The objective of the present study was to identify decidual TNF‐α‐producing cell populations that are involved in stress‐induced murine abortion. 
 METHOD: DBA/2J‐mated CBA/J female mice were exposed to ultrasonic sound stress on day 5.5 of pregnancy. The mice were randomized and half were treated with the SP NK1‐receptor antagonist (SP‐RA) RP 67580 (200 μg/mouse). Frequency and cytokine profile of CD8+ cells were evaluated by immunohistochemistry and flow cytometry. Degranulation of uterine mast cells was examined histologically.
 RESULTS: On day 13.5 of pregnancy, the uteri were removed and the resorption rate was calculated. A mean resorption rate of 38.4% was detected in stressed mice (n=10) compared to 13.1% in non‐stressed control mice (n=11, P<0.01). Injection of SP‐RA decreased the abortion rate to 18.4% in stressed mice (n=19, P<0.01). Flow cytometry revealed a stress‐related increase of TNF‐α+/CD8+ decidual T cells, which could be abrogated by SP‐RA (P<0.05). No significant differences could be observed in numbers of mast cells and total CD8+ cells in situ.
 CONCLUSION: Our data suggest that stress‐triggered abortion is mediated by SP, and SP receptor blockade abrogates stress‐triggered abortion via reduced production of TNF‐α by CD8+ T cells.

Nerve growth factor‐induced substance P in capsaicin‐insensitive vagal neurons innervating the lower mouse airway

Background Nerve growth factor (NGF) is elevated in allergic diseases such as bronchial asthma and can lead to an induction of substance P (SP) and related neuropeptides in guinea‐pigs large‐diameter, neurofilament‐positive airway neurons.