Yoko Hamai

Evidence for an Elevation in Serum Interleukin-2 and Tumor Necrosis Factor-α Levels Before the Clinical Manifestations of Preeclampsia

PROBLEM: The purpose of this study is to clarify whether the disruption of immune regulation occurs in early pregnancy before the clinical manifestations of preeclampsia.

Human leukocyte antigen-G-expressing cells differently modulate the release of cytokines from mononuclear cells present in the decidua versus peripheral blood

PROBLEM: To better understand the role of human leukocyte antigen (HLA)‐G in regulating the T helper (Th)1/Th2 cytokine balance, one of key conditions in determining the fate of pregnancy, we asked whether the presence of HLA‐G protein altered the release of cytokines from both decidual mononuclear cells and peripheral blood mononuclear cells (PBMCs).
 METHOD OF STUDY: The amounts of cytokines released from decidual mononuclear cells and PBMCs were compared in the presence or absence of HLA‐G‐expressing cells.
 RESULTS: When cocultured with HLA‐G‐expressing cells, the amounts of tumor necrosis factor‐α and interferon‐γ released from decidual mononuclear cells and PBMCs were decreased, while the amounts of interleukin (IL)‐4 from PBMCs was increased, with IL‐4 release from decidual mononuclear cells being unchanged.
 CONCLUSIONS: Upon contact with HLA‐G, decidual mononuclear cells, and PBMCs as well, modulate their ability to release cytokines in a way that may shift the Th1/Th2 balance towards relative Th2 dominance, suggesting a role for HLA‐G in maintaining pregnancy.

Early axonal and glial pathology in fetal sheep brains with leukomalacia induced by repeated umbilical cord occlusion

We conducted a chronic preparation experiment involving near term fetal sheep to evaluate the contribution of umbilical cord occlusion to fetal brain injury. In experimental groups (n = 11), complete cord occlusion for 3 min followed by 5 min release, repeated 5 times were performed at 3 days after initial surgery. Instrumental cases without cord occlusion (n = 3) and uninstrumental twins (n = 6) were also examined as controls. Multiple necrotic foci predominantly in the periventricular white matter were found in the fetal brains examined at 1-3 days after cord occlusion. To estimate the contribution of early axonal and glial reaction to brain injury the following immunohistochemical study was performed. In the lesions, coagulation necrosis, axonal swelling and microglial activation were demonstrated with amyloid precursor protein or ionized calcium binding adapter molecule 1 immunohistochemistry. The induction of tumor necrosis factor alpha and inducible nitric oxide synthase were also detected immunohistochemically in the microglia at 1 and 3 days after cord occlusion. In contrast, the reaction of glial fibrillary acidic protein positive astrocytes was faint at 1 day after occlusion, but the induction of cyclooxygenase-2 was observed. These findings suggest the glial reaction of cytokines and free radicals induced by fetal hypoxia may contribute to the occurrence of brain injury.

Analysis of human leukocyte antigen-G polymorphism including intron 4 in Japanese couples with habitual abortion.

PROBLEM: The purpose of this study was to clarify whether there is a difference between the allele frequency of human leukocyte antigen (HLA)‐G in healthy Japanese people and that of Japanese couples with habitual abortion.

Evidence for basic fibroblast growth factor as a crucial angiogenic growth factor, released from human trophoblasts during early gestation

The objective of this study was to clarify the possible angiogenesis-promoting factors from human trophoblasts in early stage gestation. The existence of angiogenic growth factors such as basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) in the condition medium from human villous trophoblasts was determined. Biological activity of angiogenic growth factors released by trophoblasts was examined using vascular endothelial cell lines. The condition medium from trophoblasts enhanced the growth of endothelial cells. Although cultured trophoblasts exhibited immunoreactive products for both bFGF and VEGF in the cytoplasm, only bFGF was detected in the condition medium by ELISA. The growth-enhancing activity of the condition medium was eliminated completely by the addition of anti-bFGF antibody but not with anti-VEGF antibody. Thus, trophoblastic cells seem to play an important role in extensive angiogenesis occurring in early gestation, mainly by releasing bFGF but not VEGF.

Pathogenetic implication of interleukin-2 expressed in preeclamptic decidual tissues : A possible mechanism of deranged vasculature of the placenta associated with preeclampsia

PROBLEM: The purpose of this study is to clarify whether IL‐2 expressed in the decidua in preeclampsia affects the angiogenesis of the placenta.

Generation of Periventricular Leukomalacia by Repeated Umbilical Cord Occlusion in Near-Term Fetal Sheep and Its Possible Pathogenetical Mechanisms

Periventricular leukomalacia (PVL) is a major cause of cerebral palsy. However, pathogenetic mechanisms of PVL have not been fully understood. Although it has been postulated that umbilical cord compression is related to the development of PVL, no animal experiments clearly demonstrated an association of umbilical cord occlusion with ‘periventricular’ white matter lesions. The purpose of this study is to determine whether umbilical cord occlusions could produce periventricular white matter lesions in fetal sheep and to examine how changes in fetal cardiovascular and metabolic variables are related to the induction of brain damage. Fourteen near-term fetal sheep underwent umbilical cord occlusion (3-min total cord occlusions 5 times at 5-min intervals). Dissections performed 24 h after cord occlusion revealed that periventricular white matter lesions were produced in 7 out of 14 sheep fetuses. According to the pattern of brain damage, we classified the fetal sheep into three groups: 5 fetuses with dominant lesions in the periventricular white matter (group I), 4 fetuses with brain lesions in the cerebral cortex and thalamus (group II) and 5 fetuses with no or minimal brain lesions (group III). Group I showed higher blood pressure and higher plasma lipid peroxide levels before cord occlusion compared to the other groups, while group II showed systemic hypotension during cord occlusion. No significant differences in changes in pH, PaCO2, PaO2 and heart rate were found between the three groups. It is speculated that PVL might be produced by an association of preexisting chronic circulatory instability with an acute episode of severe repetitive cord occlusion.

Peripheral blood mononuclear cells from women with recurrent abortion exhibit an aberrant reaction to release cytokines upon the direct contact of human leukocyte antigen-G-expressing cells.

PROBLEM: In search for pathogenesis of recurrent abortion, we examined whether lymphocytes/macrophages from women with recurrent abortion exhibited an aberrant ability to release cytokines upon the direct contact of human leukocyte antigen (HLA)‐G.

Theoretical Basis for Herbal Medicines, Tokishakuyaku-San and Sairei-To, in the Treatment of Autoimmunity-Related Recurrent Abortion by Correcting T Helper-1/T Helper-2 Balance

PROBLEM AND METHOD OF STUDY: To get insight into the basis for the empirical usage of herbal medicines in the treatment of recurrent abortion, we examined whether Tokishakuyaku‐san (Toki) and Sairei‐to (Sai) modulate T helper‐1 (Th1) and T helper‐2 (Th2) cytokine release from peripheral blood mononuclear cells (PBMCs). The effects of these medicines were investigated as related to human leukocyte antigen (HLA)‐G, a non‐classical HLA class I antigen expressed on trophoblasts and a putative crucial player involved in fetomaternal immune interplay.
 RESULTS: Toki and Sai increased the release of Th1 group cytokines, tumor necrosis factor (TNF)‐α and interferon (IFN)‐γ while preserving the inhibitory effect of HLA‐G on the release of these cytokines. As for Th2 group cytokine release, Toki was without effect in modulating interleukin (IL)‐4 release, regardless of the presence of HLA‐G, whereas Sai nullified the effect of the presence of HLA‐G to stimulate the release of IL‐4 without affecting its release in the absence of HLA‐G.
 CONCLUSION: Toki and Sai may have therapeutic potential, particularly in autoimmunity‐related recurrent abortion where Th2 response is pathologically enhanced, but not in recurrent abortion involving alloimmune fetomaternal derangement, a condition of, rather, an enhanced Th1 response.

Quantitative assessment of human leukocyte antigen-G protein in amniotic fluid by a double-determinant enzyme-linked immunosorbent assay using anti-human leukocyte antigen-G-specific antibody '87G'.

PROBLEM: The objective of this study was to establish an enzyme‐linked immunosorbent assay (ELISA) system, in an attempt to quantify the amount of human leukocyte antigen (HLA)‐G protein in amniotic fluid.