Terumasa Sugano

Platelet-Activating Factor Induces an Imbalance Between MatrixMetalloproteinase-1 and Tissue Inhibitor of Metalloproteinases-1 Expressionin Human Uterine Cervical Fibroblasts

Abstract Platelet-activating factor (PAF) is involved in such reproductive processes as parturition. We investigated the effect of PAF on the expression of matrix metalloproteinase-1 (MMP-1) and that of tissue inhibitor of metalloproteinases-1 (TIMP-1) in human uterine cervical fibroblasts. Uterine cervical tissue was obtained from patients who underwent cesarean section at term. Collagenase-dispersed fibroblasts were cultured and used in the experiments. PAF receptor was identified in the uterine cervical fibroblasts by use of reverse transcription-polymerase chain reaction and Southern blot analysis. Northern blot analysis showed that PAF increased the expression of MMP-1 mRNA in a time-dependent manner, whereas expression of TIMP-1 mRNA was not affected by PAF. Concentration of MMP-1 protein in the PAF-treated culture media significantly exceeded that in control cultures. The PAF-induced production of MMP-1 protein was abolished by treatment with WEB 2170, a specific PAF receptor antagonist. Results suggest that PAF may accelerate collagenolysis in the human uterine cervix by inducing an imbalance in the activity between MMP-1 and TIMP-1, thus contributing to the cervical ripening during parturition.

Rhabdomyolysis caused by tocolysis with oral ritodrine hydrochloride in a pregnant patient with myotonic dystrophy.

Drug-induced rhabdomyolysis during pregnancy is extremely rare. We report here a rare case of ritodrine-hydrochloride-induced rhabdomyolysis in a pregnant patient with myotonic dystrophy. A 32-year-old primigravida was admitted because of premature labor at 31 weeks of gestation. She had been diagnosed as having myotonic dystrophy by electromyographic investigations and abnormal serum creatinine phosphokinase (CPK) levels. Tocolysis was initiated with oral ritodrine hydrochloride (15 mg/day) alone. There was a prompt response to the ritodrine hydrochloride. Three days after administration began, serum CPK levels had become markedly elevated to 10,897 mg/dl and myoglobinuria was detected (1,800 ng/dl), suggesting the presence of rhabdomyolysis. There was no evidence of worsening of the myotonic symptoms. Tocolysis was stopped immediately, and the laboratory data improved gradually. At 37 weeks of gestation, she spontaneously delivered a healthy male baby. Rhabdomyolysis has been recognized as a complication of tocolytic therapy with ritodrine hydrochloride. Therefore, β-adrenergic agents should be used with great care, especially for patients with myotonic dystrophy, because of these agents’ tendency to aggravate or precipitate myotonia and to induce rhabdomyolysis.

Expression of collagen XVIII mRNA and protein in human umbilical vein and placenta

Endostatin is a potent angiogenic inhibitor that is derived from collagen XVIII by proteolytic cleavage. Localization of collagen XVIII has been reported in the basement membrane of blood vessels. To examine the involvement of collagen XVIII/endostatin during pregnancy, the distribution of collagen XVIII/endostatin protein in human umbilical vein was evaluated by immunohistochemistry. The expression of collagen XVIII/endostatin in cultured human umbilical vein endothelial cells (HUVEC) was also examined by immunocytochemistry and Northern blot analysis. To examine the release of endostatin in vivo and in vitro, concentrations of endostatin in umbilical venous blood and in HUVEC culture medium were determined using an enzyme-linked immunosorbent assay. Collagen XVIII/endostatin protein was localized to endothelial cells and their basement membrane in the umbilical vein. The expression of collagen XVIII mRNA and protein was detected in HUVEC. However, endostatin was not detected in umbilical venous blood or in HUVEC culture medium. The absence of endostatin release and the presence of its parental protein, collagen XVIII, suggest that the cleavage mechanisms of endostatin might be strongly inhibited under the physiological conditions present during pregnancy. It is therefore considered that vasculature in the feto-placental unit is highly angiogenic, even at the time of parturition.

Vertebral Bone Mineral Density in Postpartum Women

The purpose of this study was to measure the bone mineral density of the lumbar spine (L2-L4) in healthy postpartum women following term delivery, and to evaluate factors associated with bone mineral density. Using dual energy X-ray absorptiometry, the bone mineral density of the lumbar spine was determined during 1 year in 123 healthy postpartum Japanese women following term delivery. The mean bone mineral density of the lumbar spine was 1.007 +/- 0.108 g/cm2 (range 0.731-1.252 g/cm2). Thus, there were wide inter-individual differences. Also, this result was in agreement with the peak bone mass previously reported for other Japanese women. Multiple regression analysis and linear regression analysis showed that weight and body mass index were each significantly correlated with bone mineral density of the lumbar spine. Age, parity, height, and babys birth weight were not contributory.

The effect of epidermal growth factor on production of vascular endothelial growth factor by amnion-derived (WISH) cells

Our objective was to clarify the physiological role of vascular endothelial growth factor (VEGF) by amnion-derived (WISH) cells. WISH cells were cultured, and the effect of epidermal growth factor (EGF), mitogen-activated protein (MAP) kinase kinase or extracellular signal-regulated kinase (ERK) kinase (MEK) inhibitors (U0126) or phosphatidylinositol (PI) 3-kinase on the production of VEGF was examined. VEGF was assayed by ELISA. The activation of MAP kinase and akt, which is phosphorylated by PI 3-kinase, were detected by Western blot analysis using anti-phosphorylated MAP kinase antibody and anti-phosphorylated akt antibody. In the time course of VEGF production following EGF treatment, VEGF production showed a significant increase only after 16 (p < 0.01)–32 h (p < 0.01). EGF increased the production of VEGF by WISH cells in a dose-dependent manner. The MAP kinase and akt activity were determined by treatment with EGF. VEGF production was significantly decreased following pretreatment with U0126 or wortmannin for two hours before treatment with EGF (p < 0.01, p < 0.01). WISH cells appeared to produce VEGF via a mechanism involving tyrosine kinase activation of EGF receptor and MAP kinase or PI 3-kinase. It is suggested that VEGF may contribute to the neovascularization and proliferation of the placenta and gestational tissue, and EGF may play an important role in regulation of VEGF production in the placenta.

Effect of ceramide analogs on interleukin-1α-induced production of prostaglandin E2 by amnion-derived (WISH) cells

Background. Prostaglandin E2 (PGE2) is reportedly synthesized in the amnion, and its levels are increased during labor. Our objective was to measure the level of PGE2 induced by interleukin (IL)‐1α following treatment with ceramide analogs in amnion‐derived cells.

Platelet-activating factor mediated decidual cytokine network during term and preterm parturition — A review —

Summary PAF, a potent lipid mediator, has been implicated in a number of reproductive processes, including parturition. PAF has been shown to stimulate prostaglandin E 2 production in fetal membranes and to cause myometrial contraction. PAF metabolism in the decidua and its modulation by endotoxin or cytokines has been investigated. Decidual macrophages secrete PAF-AH activity of the plasma type that inactivates PAF. LPS, TNF-α, and IL-1β inhibited the PAF-AH secretion by decidual macrophages. The LPS-inhibition was partially reversed by IL-1ra or by neutralizing antibodies against TNF-α and IL-1β. The effect of IL-1β on the secretion was abolished by IL-1ra. IFN-γ, IL-6, and IL-8 also inhibited the PAF-AH secretion, while M-CSF increased the enzyme secretion. These observations lend additional support to the concept that PAF is pathophysiologically involved in parturition or preterm labor caused by chorioamnionitis, forming a PAF-mediated cytokine network at the fetal-maternal decidual interface.

The inhibitory effect of protein kinase C activation on the secretion of platelet-activating factor-acetylhydrolase by human decidual macrophages

Platelet-activating factor (PAF) metabolism in the maternal-fetal decidual interface has been investigated. Human decidua was obtained from patients at term and not in labor after cesarean section. The cells were isolated by enzymic digestion, followed by Ficoll-Paque centrifugation, or were purified further by discontinuous Percoll density gradient centrifugation. Cell populations were analyzed by flow cytometry after labeling with macrophage-specific antibodies. Twenty-seven percent of the cells obtained after enzymic digestion and Ficoll-Paque density gradient centrifugation had macrophage surface markers. The decidual cell population secreted PAF-acetylhydrolase (PAF-AH) activity. The secreted PAF-AH was the plasma-type isozyme. Synthesis and secretion was inhibited by actinomycin-D or cycloheximide. The PAF-AH activity secreted into the culture medium correlated positively with the number of macrophages. Flow cytometric purification yielded a 96% macrophage marker-positive population. The macrophages were shown to be the only cell types of decidual tissue that secreted PAF-AH. Treatment with anti-CD14 monoclonal antibody and complement specifically blocked PAF-AH secretion by collagenase-dispersed cells. It is concluded that decidual macrophages produce and secrete PAF-AH of the plasma type, and it is suggested that these cells may play an important role in PAF metabolism during parturition.