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Background: Amniotic fluid contains a significant level of urinary trypsin inhibitor (UTI). Previously, we reported that UTI inhibits calcium influx of myometrium and it is effective in preventing uterine contraction. This study examined the effects of UTI upon potassium channels, which is important for membrane excitability., Methods: Whole-cell patch-clamp recordings were performed in fibroblasts derived from human fetal skin. Potassium currents were recorded and the effects of exogenous UTI and/or cadmium determined., Results: Tetraethylammonium sensitive potassium currents were elicited by step or ramp stimulations at depolarized membrane potentials (over +30 mV). Administration of 1 micro M UTI significantly increased these potassium currents by 16.9%. When calcium channels were blocked by the administration of cadmium, UTI increased the rest of the potassium currents by 4.8%. This indicates that UTI increased calcium-dependent potassium currents by 94.8% but only increased voltage-dependent potassium currents by 4.8%., Conclusions: Urinary trypsin inhibitor is a physiological substance of fetal origin that modulates calcium-dependent and voltage-dependent potassium channels. These data suggest that UTI is capable of regulating the membrane properties of the fetal and myometrial cells in contact with amniotic fluid.

Urinary trypsin inhibitor (UTI) forms membrane complexes with UTI-binding proteins (UTI-BPs) and initiates modulation of urokinase-type plasminogen activator (uPA) expression, which results in UTI-mediated suppression of cell invasiveness. It has been established that suppression of uPA expression and invasiveness by UTI is mediated through inhibition of protein kinase C-dependent signaling pathways and that human chondrosarcoma cell line HCS-2/8 expresses two types of UTI-BPs; a 40-kDa UTI-BP (UTI-BP(40)), which is identical to link protein (LP), and a 45-kDa UTI-BP (UTI-BP(45)). Here we characterize binding properties of UTI-BPs.UTI complexes in the cells. In vitro ligand blot, cell binding and competition assays, and Scatchard analyses demonstrate that both UTI-BP(40) and UTI-BP(45) bind (125)I-UTI. A deglycosylated form of UTI (NG-UTI), from which the chondroitin-sulfate side chain has been removed, binds only to UTI-BP(40). Additional experiments, using various reagents to block binding of (125)I-UTI and NG-UTI to the UTI-BP(40) and UTI-BP(45) confirm that the chondroitin sulfate side chain of UTI is required for its binding to UTI-BP(45). Analysis of binding of (125)I-UTI and NG-UTI to the cells suggests that low affinity binding sites are the UTI-BP(40) (which can bind NG-UTI), and the high affinity sites are the UTI-BP(45). In addition, UTI-induced suppression of phorbol ester stimulated up-regulation of uPA is inhibited by reagents that were shown to prevent binding of UTI to the 40- and 45-kDa proteins. We conclude that UTI must bind to both of the UTI-BPs to suppress uPA up-regulation.

Urinary trypsin inhibitor (UTI) has several roles other than protease inhibition. It is suggested that UTI inhibits calcium influx in cultured cells and that the chondroitin sulfate chain of UTI may play an important role. In order to clarify the mechanistic features of this phenomenon, the chondroitin sulfate chain of UTI was analyzed by (1)H-NMR. The samples were highly purified UTI dissolved in D(2)O in the presence or absence of Ca(2+), Mg(2+) and Na(+). 1D-spectra were obtained and T(1) values of detected signals were estimated from the inversion-recovery method. The addition of Ca(2+) to UTI caused a chemical shift to downfield, line broadening and a reduction of T(1) values at several signals from chondroitin sulfate moiety (especially at axial H-2 of GalNAc), whereas Mg(2+) and Na(+) had no significant effect. Some of the signals in the linkage region of chondroitin sulfate chain showed marked line broadening by Ca(2+). The reduction of T(1) values implies formation of a complex. It is suggested that Ca(2+) generates the sulfate salt and interacts with other polar groups in the chondroitin sulfate chain, thereby causing bridging between UTI molecules. Several properties of UTI may be related to this interaction of Ca(2+) with chondroitin sulfate chains.

The mechanisms by which urinary trypsin inhibitor (UTI) prevents preterm premature rupture of fetal membrane and premature cervical ripening were investigated. We, therefore, examined the effects of UTI on the production of matrix metalloproteinases (MMPs) which closely participate in the breakdown of extracellular matrix in cultured human uterine cervical fibroblasts and human chorionic cells. UTI suppressed specifically the production of interstitial procollagenase/proMMP-1 and prostromelysin 1/proMMP-3 from both cells in a dose-dependent manner (0.32-1.28 microM). This suppression was accompanied by a decrease in steady-state levels of their mRNAs. These results indicate for the first time that UTI down-regulates the production of proMMP-1 and proMMP-3 accompanying with the decrease in the expression of their mRNAs, and therefore UTI actually participates in the maintenance of fetal membranes and/or uterine cervix by overall suppression of MMP production along with the known inhibitory actions towards serine proteinases.

Preincubation of HL60 cells and HUVEC cells with urinary trypsin inhibitor (UTI) inhibited increase of cytosolic free Ca2+ induced by LPS. In contrast, an increase of cytosolic free Ca2+ induced by LPS was not inhibited by deglycosylated UTI, UTI treated with monoclonal antibody of chondroitin sulfate. 45Ca2+ binding showed that UTI binds 45Ca2+ dose-dependently. Scatchard plot analysis showed that UTI has two binding sites for Ca2+, a high affinity binding site (Kd=15 microM) and a low affinity site (Kd=150 microM), and that UTI has more than 70 Ca2+ binding sites per molecule. The Ca2+ binding capacity of deglycosylated UTI and UTI treated with monoclonal antibody of chondroitin sulfate was markedly depressed. Furthermore, UTI forms multi-polymers in the presence of Ca2+ as demonstrated by gel filtration and agarose gel electrophoresis. These results suggest that UTI is a physiological Ca2+ chelator on the cells and that the action is due to chondroitin sulfate chains of UTI., (Copyright 1997 Academic Press.)

Unlabelled: Prevention of preterm delivery is one of the difficult problems facing obstetricians. beta Adrenergic agonists, especially ritodrine, are commonly used in these cases., Objectives: The aim of this research was to study and compare the effect of urinary trypsin inhibitor (UTI) which has anti-inflammatory anti-cytokine effects with ritodrine in treating preterm labor., Study Design: Patients in preterm delivery were randomly selected to be treated either by ritodrine or UTI. In the ritodrine group, uterine contractions were initially suppressed by high doses of ritodrine (up to 300 micrograms/min) and then a maintenance dose was given until 35 weeks of gestation. In the UTI group one vaginal suppository (5000 U) was used daily for 2 weeks. Patients with recurrent preterm uterine contraction during the initial 14 days of treatment, who needed course of other drugs to suppress the contractions, were excluded from the study. Patients responding to the drugs were followed until delivery. Tocolytic index and elastase concentration in the cervical mucus was calculated. Recurrence rate of uterine contraction and time of elongation of pregnancy since the beginning of treatment was calculated., Results: UTI was more effective than ritodrine in inhibition of recurrent uterine contraction and elongation of pregnancy. No side effects could be observed after treatment with UTI for the mother or the fetus., Conclusion: UTI may be a new therapeutic method for the inhibition of preterm delivery through suppression of cytokines and inflammatory mediators.

The aim of this research was to study the concentration of urinary trypsin inhibitor in amniotic fluid (AF) and its effect on myometrial contraction in term and preterm deliveries. Urinary trypsin inhibitor was measured in AF of term and preterm labor. Immunohistochemical staining of amnion and myometrium was carried out. Isometric uterine contraction was studied to elucidate the effect of AF and urinary trypsin inhibitor on the contractile activity of term and preterm myometrium. The effect of urinary trypsin inhibitor on the production of prostaglandin E2 (PGE2) from myometrial cultures stimulated by IL-8, IL-1 and LPS was verified. Urinary trypsin inhibitor was significantly increased in AF of cases of preterm delivery (p < 0.0001). Amnion and myometrium of preterm deliveries were faintly stained for urinary trypsin inhibitor compared to term delivery. Amniotic fluid and urinary trypsin inhibitor could successfully inhibit-myometrial contraction. Also, urinary trypsin inhibitor could significantly inhibit the production of PGE2 in the myometrial cell cultures stimulated by IL-1 and LPS (p < 0.001 and 0.0005). IL-8 has no significant effect on PGE2 production from myometrial cell culture. Urinary trypsin inhibitor suppresses myometrial contraction in term and preterm deliveries. It may play a role in maintaining normal pregnancy and preventing preterm delivery.

Objective: The aim of this research was to elucidate the mechanism of action of urinary trypsin inhibitor, a Kunitz-type protease inhibitor, in suppressing uterine muscle contraction., Study Design: An isometric uterine contraction test was used to study this inhibitory effect of urinary trypsin inhibitor on the myometrium. Oxytocin, prostaglandin F2 alpha, and lipopolysaccharide were used to stimulate myometrial contraction. Prostaglandins F2 alpha and E2 were measured in the buffer solution. Influx of calcium into uterine smooth muscle cells was assessed by digital imaging microscopy., Results: After incubation with urinary trypsin inhibitor or fetal urine, myometrial contractions stimulated by oxytocin, prostaglandin F2 alpha or lipopolysaccharide were suppressed completely. The concentrations of prostaglandins F2 alpha and E2 in the buffer solution during the isometric contraction test were significantly increased by lipopolysaccharide stimulation, but when urinary trypsin inhibitor was present in the buffer solution the concentrations of prostaglandins F2 alpha or E2 did not change significantly. Preincubation with urinary trypsin inhibitor also inhibited calcium influx, resulting in no detectable change in the intracellular free calcium concentration of smooth muscle cells., Conclusion: We proposed that urinary trypsin inhibitor from fetal urine inhibits uterine muscle contraction by regulation of intracellular Ca++.

Unlabelled: Unknown signals from the fetus are thought to be involved in the onset of parturition. We recently discovered that urinary trypsin inhibitor (UTI) from fetal urine inhibits uterine muscle contraction., Objectives: The aim of this research was to elucidate the mechanism of action of UTI in suppressing cervical maturation., Study Design: Non-pregnant and pregnant rabbits pretreated with and without UTI suppositories containing 1000 U (400 micrograms) for 3 days were treated for 2 days with vaginal suppositories containing 100 ng of interleukin-8 (IL-8)., Results: IL-8 induced softening and dilatation of the rabbit cervices. In contrast UTI inhibited IL-8 induced cervical softening and dilatation. Water content, collagen content, neutrophil counts, elastase activity and collagenase activity of the cervix were increased by IL-8, but they did not increase by IL-8 with UTI., Conclusion: These results suggest that UTI inhibits cervical maturation induced by IL-8.

Urinary trypsin inhibitor (UTI) has a multipotent inhibitory effect on proteases such as trypsin, chymotrypsin, plasmin, human leukocyte elastase, or hyaluronidase. UTI can bind easily to its receptors on various types of tumor cells (human ovarian cancer HOC-I cells, human choriocarcinoma SMT-cc1 cells, and murine Lewis lung carcinoma 3LL cells). Our results show that the UTI receptors of some tumor cells have a possible role in modulating plasmin activity on the cell surface and prevention of tumor cell invasion and metastasis (H. Kobayashi et al., J. Biol. Chem., 269; 20642-20647, 1994). UTI interacts with tumor cells as a negative modulator of the invasive cells. We investigated whether this effect may be mediated by UTI binding to the cell surface receptors. In addition, the role of peptide sequences from each UTI domain and their interaction with tumor cells were investigated. UTI derivatized with biotin or FITC was taken up by tumor cells in a dose-dependent manner. This cell association was inhibited with a monoclonal antibody D1, which specifically recognizes NH2 terminus (domain I) of UTI. The binding was inhibited by fluid phase UTI, but not HI-8, COOH terminus (domain II) of UTI, suggesting that UTI binds to cells through a site in the UTI domain I. Furthermore, we found that UTI, HI-8 and a number of peptides containing Arg-Gly-Pro-Cys-Arg-Ala-Phe-Ile promoted the inhibition of tumor cell invasion. This site corresponds to the plasmin-inhibiting domain within HI-8. The possibility that UTI binding to tumor cells might be involved in the prevention of tumor cell invasion in vitro was excluded since HI-8, lacking domain I, promotes the inhibition of tumor cell invasion with essentially the same affinity as UTI. All these data allow us to conclude that inhibition of tumor cell invasion is mediated by domain II, which possesses anti-plasmin activity.

The protease inhibitor part of inter-alpha trypsin inhibitor is identical to urinary trypsin inhibitor (UTI). Preincubation of neutrophils and HUVEC cells with UTI inhibited increase of cytosolic free Ca2+ induced by LPS. Increase of cytosolic free Ca2+ induced by LPS in the presence of EGTA was also inhibited by UTI. In contrast, UTI did not inhibit increase of cytosolic free Ca2+ in cells stimulated by Ca2+ ionophore with or without EGTA. The effects of nine synthetic peptides of UTI on the concentration of cytosolic free Ca2+ in the neutrophils induced by LPS were examined. Preincubation with a peptide of UTI domain 2, NLPIVRGPCRAFIQL (83-97), was completely inhibited by the increase of cytosolic free Ca2+ in neutrophils. This region is identical to the trypsin inhibitor site of UTI. We propose that a function of UTI other than as a protease inhibitor is in regulation of intracellular Ca2+ and that this is due to its trypsin inhibitor region.

To determine the intrauterine defensive role of urinary trypsin inhibitor (UTI), we studied the effects of UTI in amniotic fluid, fetal membranes and myometrium. The level of UTI was 94 +/- 34 U/ml in neonatal urine (compared to adult urine 8.0 +/- 6.0 U/ml) and 88 +/- 37 U/ml in amniotic fluid. This may indicate that the main source of UTI in the amniotic fluid is the fetal urine. UTI was found to be concentrated in vernix, fetal intestine, amniotic membranes and uterine myometrium. Immunostaining of term amnion revealed a dark staining for UTI, whereas in premature deliveries UTI staining was markedly decreased. In myometrium, the concentration of UTI was found to be increased during pregnancy compared to non pregnant myometrium. Also, placentas were well stained for UTI in term pregnancy. Thus UTI has an important role in amniotic fluid, fetal membranes, placenta and uterine muscles. UTI has an inhibitory effect on several enzymes and cytokines. UTI was found to inhibit neutrophil elastase activity as well as trypsin activity. Its inhibitory activity was increased in the presence of lipid. LPS stimulated amnion cells trapped more UTI than unstimulated amnion cells. UTI in amnion cells was released after addition of 1% meconium solution. UTI was also found to inhibit the effect of IL-1, TNF and interleukin-8 on amnion. These results indicate that UTI localized in amnion is important in the protection of fetal membrane especially against bacterial infections and cytokines. It is known that endothelin (ET), prostaglandin F2 alpha (PGF2 alpha) and oxytocin can induce uterine contraction. UTI could inhibit uterine contractions stimulated by ET, PGF2 alpha and oxytocin in isometric contraction test. UTI could also inhibit cervical maturation induced by interleukin-8. Therefore UTI is essential for maintenance of pregnancy. From the isometric contraction tests, we assumed that UTI might works through regulation of calcium entry or availability in the cells. Initial increase in intracellular calcium was also inhibited by UTI pre incubation dose dependantly. We examined the change in intracellular calcium at single cell level by digital image analysis with Fura 2AM as a calcium probe. At resting level UTI incubation did not produce any significant changes in intracellular free calcium. Thrombin, LPS, interleukin-8 and ET-1, known calcium agonists could increase intracellular calcium in fibroblasts, amnion and uterine myocytes. Whereas as the same doses of those known calcium agonists could not change the intracellular free Ca2+ concentrations in UTI pre incubated fibroblasts, amnion cells and uterine smooth muscle cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Urinary trypsin inhibitor-related substance (UTI-R) was measured in the amniotic fluid (n = 30), first neonatal urine (n = 10), meconium (n = 10), and adult urine (n = 10). The concentration of UTI-R excreted in the neonatal urine was significantly higher than in adult urine and meconium. Positive immunostaining for UTI was observed in amnion, umbilical cord and placenta. The effect of UTI was studied on the amnion using fura-2-acetoxymethyl ester. Interleukin-1 beta (IL-1 beta) and tumor necrosis factor-beta (TNF-beta) led to a significant increase in relative fluorescence release (RFR) of fura-2 (p < 0.05 and p < 0.02, respectively) while endotoxin did not show significant changes of RFR of fura-2. The effect of IL-1 beta and TNF-beta was almost abolished after incubation of UTI with the amnion cells (p < 0.03). This suggests that UTI may have a protective effect on the amnion especially against IL-1 beta and TNF-beta.

Cervical maturation, dilatation and uterine contraction in imminent premature delivery are closely related to chemical mediators from activated granulocytes which infiltrate into the cervix. It is known that urinastatin (urinary trypsin inhibitor, UTI) inhibits many kinds of chemical mediators from granulocytes and macrophages such as granulocyte elastase (elastase) and interleukin 1. We examined the effect of a UTI suppository on uterine contraction and the elastase level in cervical mucus in cases of imminent premature delivery. We treated 43 cases of imminent premature delivery with tocolysis index 3 or 4 with 4 kinds of therapy: Group A (N = 12): ritodorine drop infusion therapy; Group B (N = 9): daily UTI suppository (1,000U) therapy; Group C (N = 14): daily UTI suppository + ritodorine drop infusion therapy; Group D: daily UTI suppository + ritodorine drop infusion + antibiotics (oral cepharosporine) therapy. The elastase level of cervical mucus before treatment was 0.76 +/- 0.40 micrograms/ml in group A, 0.93 +/- 0.43 micrograms/ml in group B, 0.85 +/- 0.40 micrograms/ml in group C and 0.90 +/- 0.41 micrograms/ml in group D. There was no significant difference between these groups. The elastase level in cervical mucus was 0.75 +/- 0.47 micrograms/ml in group A, 0.27 +/- 0.35 micrograms/ml in group B, 0.27 +/- 0.33 micrograms/ml in group C and 0.30 +/- 0.19 micrograms/ml in group D, respectively. The elastase level was decreased significantly in groups B, C and D. The time taken to depress uterine contraction was 65 +/- 66 min in group A, 375 +/- 336 min in group B, 70 +/- 64 min in group C and 58 +/- 53 min in group D, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)