Noboru Matsuzaki

Production of interleukin-6 by normal human trophoblast.

The placenta plays a number of important roles during pregnancy, some of which might be mediated by cytokines with multiple activities such as IL-6. Using an IL-6-dependent cell line, MH6o.BSF2, we showed that the placenta released IL-6 into the culture supernatant. Analysis of single-cell suspensions of placental cells determined the major source of IL-6 to be trophoblast. Using a mouse monoclonal antibody specific for IL-6 (alpha BSF2-I66), immuno-histochemical analysis of placental specimens demonstrated the localization of IL-6 only in the trophoblast layer. Additional immunocytochemical studies with single-cell suspensions of trophoblasts demonstrated the preferential presence of IL-6 molecules in syncytiotrophoblasts rather than cytotrophoblasts. The evidence that a high titer of IL-6 is produced spontaneously by syncytiotrophoblasts indicates that IL-6 may play immunological roles in fetomaternal interactions by means of IL-6-driven multiple immunoregulatory activities.

The enhanced production of placental interleukin-1 during labor and intrauterine infection*

The purpose of this study was to determine the effect of labor and chorioamnionitis in interleukin-1 production by human placenta. We studied the activity of the placenta to produce interleukin-1 with an enzyme immunoassay by culturing tissue blocks. The placental tissue obtained after labor produced a larger amount of interleukin-1 than placental tissue obtained before labor. All the placental tissues produced more interleukin-1 beta than interleukin-1 alpha. The placentas with labor and chorioamnionitis produced about seventeenfold more interleukin-1 than placentas with labor only. We immunohistochemically identified interleukin-1--producing cells in the placenta and found that syncytiotrophoblasts produced both interleukin-1 alpha and interleukin-1 beta, while Hofbauer cells produced only interleukin-1 beta. In vitro analysis of the trophoblast activities to produce interleukin-1 revealed that microbial byproducts enhanced interleukin-1 production, possibly inducing accumulation of interleukin-1 receptor-positive cells at the sites of inflammation. In addition to stimulation of prostaglandin biosynthesis and labor, the placental interleukin-1 may act as an inflammatory mediator, leading to systemic and local changes at fetomaternal interface and activating fetomaternal immune systems against intrauterine infection.

Plasma Nitric Oxide Levels in Pregnant Patients with Preeclampsia and Essential Hypertension

Nitric oxide (NO) production may be an important causal factor in hypertensive disorders during pregnancy. The plasma concentrations of NO2-(+) NO3-, stable metabolites of NO, were measured in 70 nonpregnant women, 323 normotensive pregnant women, 23 pregnant patients with preeclampsia, and 7 pregnant patients with essential hypertension. The normotensive women had higher plasma concentrations (30.0 +/- 0.6 mumol/l) than nonpregnant women (18.3 +/- 1.0 mumol/l; p < 0.0001). The plasma concentrations in the patients with preeclampsia (45.6 +/- 2.3 mumol/l) were higher than in the normotensive women (30.3 +/- 1.0 mumol/l; p < 0.0001) and were correlated with the systolic blood pressure (r = 0.442; p < 0.05). However, pregnant patients with underlying essential hypertension had significantly lower plasma concentrations (19.1 +/- 3.0 mumol/l; p < 0.005). These findings suggest that NO contributes to maternal vasodilation, the maintenance of uterine quiescence, and the pathogenesis and clinical features of hypertensive disorders during pregnancy.

Binding Sites for Interleukin-6 in the Anterior Pituitary Gland

Interleukin-6 (IL-6) binding site in the rat anterior pituitary gland was characterized using radioiodinated human recombinant (hr) IL-6. Results showed that the anterior pituitary gland contained 170 binding sites per cell of a single class with a dissociation constant of 2.7 x 10(-9) M. The binding of 125I-hrIL-6 to the rat anterior pituitary gland was competitively inhibited by unlabeled hrIL-6, but not by hrIL-1 alpha, hrIL-1 beta, hrIL-2 or hr-interferon-gamma, indicating these binding sites are specific for IL-6. We also demonstrated mouse IL-6 receptor gene expression in the rat anterior pituitary gland by Northern blot analysis. Furthermore, the IL-6 receptor was detected on human gonadotrophs by the double immunofluorescence method. Our findings demonstrate the presence and expression of IL-6 binding site in the rat anterior pituitary gland and the presence of IL-6 binding site on human gonadotrophs, suggesting the important role of IL-6 binding site in pituitary hormone release in both species.

Detection of interleukin-8 (IL-8) in seminal plasma and elevated IL-8 in seminal plasma of infertile patients with leukospermia.

OBJECTIVE To determine if interleukin-8 (IL-8) is a normal constituent of seminal plasma and if leukospermia is a factor determining its elevation. DESIGN Seminal plasma from 58 men obtained by masturbation was examined for the presence of IL-8 using an IL-8 specific sandwich ELISA. Semen samples were obtained from 34 infertile men without leukospermia, 10 infertile men with leukospermia, and 14 proven fertile men. The correlation of amount of IL-8 in seminal plasma with some spermiogram parameters and the amount of polymorphonuclear (PMN) elastase was statistically evaluated. RESULTS Immunoreactive IL-8 was observed in the seminal plasma of all 58 subjects. The IL-8 titer in seminal plasma of patients with leukospermia (6.16 +/- 0.82 micrograms/L) was significantly higher than that in seminal plasma of patients without leukospermia (2.35 +/- 0.34 micrograms/L) and fertile men (1.64 +/- 0.29 micrograms/L). There was a high degree of correlation between PMN elastase and IL-8 levels in seminal plasma. CONCLUSIONS These findings demonstrate IL-8 to be in seminal plasma and elevated IL-8 levels in infertile patients with leukospermia.

Localization of three subtypes of Fcγ receptors in human placenta by immunohistochemical analysis

We investigated the localization of the three subtypes of (Fc gamma R) in the normal human placenta using immunohistochemical and immunocytochemical techniques with specific monoclonal antibodies. The analysis revealed that Fc gamma RI was expressed on Hofbauer cells, that Fc gamma RII was expressed on Hofbauer cells and endothelial cells of fetal vessels, while Fc gamma RIII was expressed on trophoblasts, especially syncytiotrophoblasts. Moreover, we demonstrated that the expression of Fc gamma RI and Fc gamma RII on Hofbauer cells and endothelial cells of the fetal vessels in the 1st trimester placenta was different from that in the 3rd trimester placenta. These results, therefore, indicate that the three subtypes of Fc gamma R in the human placenta may contribute to maintenance of placental functions, because each Fc gamma R molecule displays unique biological functions similar to those on leukocytes.

Elevated Nitric Oxide Concentration in the Seminal Plasma of Infertile Males: Nitric Oxide Inhibits Sperm Motility

PROBLEM: To evaluate the “effect of nitric oxide in the seminal plasma on sperm motility. METHOD: Seminal plasma concentrations of NO2—, a stable end product of nitric oxide, of 108 males of infertile couples and 15 proven fertile donors were measured and compared with spermatogram parameters. Motile sperm was incubated with a nitric oxide‐generating drug, sodium nitroprusside, for 6 hr in the absence or presence of oxyhemoglobin, an inhibitor of nitric oxide.

Placental interleukin-6 production is enhanced in intrauterine infection but not in labor

OBJECTIVE Because interleukin-6 is an important mediator in the host defense mechanism against infection and tissue damage, we studied the capacity of placentas with or without either labor or chorioamnionitis in the third trimester to produce interleukin-6. STUDY DESIGN The placental blocks were cultured, and their interleukin-6 titers were measured by a bioassay. RESULTS Placentas with labor produced a similar amount of interleukin-6 to placentas without labor. In contrast, placentas with chorioamnionitis produced much more interleukin-6 than the placentas with or without labor (p < 0.0001). CONCLUSION Placental interleukin-6 is thus surmised to participate in potentiation of the placental and fetomaternal defense mechanisms together with placental interleukin-1 during chorioamnionitis.

Alteration of p16 and p15 genes in common epithelial ovarian tumors

We have examined the roles of 2 putative tumor‐suppressor genes, the p16 and p15 inhibitor‐of‐cyclin‐dependent‐kinase genes, in the most commonly occurring epithelial tumors of the human ovary. Expression of p16 mRNA, examined by RT‐PCR, was significantly reduced in 15 of the 48 tumors. Aberrant expression of p16 protein, detected by immunohistochemistry, occurred in 22 of 60 tumors, more frequently in low‐grade tumors, and had significant correlation with low p16 mRNA expression. Hypermethylation of a site within the 5′‐CpG island of the p16 gene was significantly associated with loss of p16 mRNA and protein expression. Homozygous gene deletion, evaluated by differential PCR analysis, was found in 2 tumors for the p16 gene and in 1 tumor for the p15 gene among 70 ovarian tumors examined. PCR‐SSCP analysis detected point mutations in p16 in 4 tumors and in p15 in 1 tumor. One was a 38‐bp deletion, from codons 48 to 60, in a mucinous tumor of low malignant potential; another was a non‐sense mutation in codon 60 in a mucinous adenocarcinoma. The remaining 2 mutations were mis‐sense mutations, one in codon 58 and the other in codon 60, in 2 endometrioid adenocarcinomas. We conclude that inactivation of p16, by loss of p16 mRNA and protein expression as a consequence of hypermethylation of the 5′‐CpG island, rather than by gene deletion or point mutation, may play an important role in the genesis of human ovarian epithelial tumors. Int. J. Cancer 74:148‐155, 1997.

Human placental Fc receptors

Summary Human immunoglobulin G (IgG) Fc receptors are important in the materno—fetal relationship. Three classes of IgG Fc receptors are recognized which generate multiple isoforms, most of which are expressed in different cellular components of human placenta at different times during pregnancy. Although the distinct biological functions of FcγR phenotypes expressed in human placenta are still unknown, recent data provide evidence for an important association between the FcγR phenotype and transcytosis of IgG in the placenta. Selective transfer of maternal IgG across the placenta provides passive immunity to the fetus during the period when its own immune system is gaining protective potential. Furthermore, placenta-specific macrophages may contribute through FcγR-mediated phagocytosis to the protection of the fetus from either infection or maternal immune attack against paternally inherited fetal antigens. Ontogeny and expression of various isoforms of FcγR subtypes may be the key to the elucidation of the transport mechanism of maternal IgG to the fetus, in addition to the determination of the mechanisms of placental protection of the fetus against the maternal immune system.