Recombinant human lactoferrin inhibits matrix metalloproteinase (MMP-2, MMP-3, and MMP-9) activity in a rabbit preterm delivery model.

AIM: To investigate the effect of recombinant human lactoferrin (rh-LF) on the expression of matrix metalloproteinase as a marker of cervical maturation, using a rabbit preterm delivery model in which preterm labor was induced by bacteria. METHODS: We used cervical tissues that had been excised in a previous study in which rabbits were randomly assigned to receive either inoculation with Escherichia coli (E. coli) or saline solution and to receive pretreatment with or without rh-LF inserted into the cervix two hours before bacterial inoculation (Condition A: saline + saline; Condition B: rh-LF + E. coli; Condition C: saline +E. coli). E. coli, saline solution, and rh-LF were inserted into the cervix using a hysteroscope and a sterile polyethylene cannula. Both cervices of the rabbit uterus, which is bicorpus-bicolli, were taken out and preserved, and expression of matrix metalloproteinases MMP-2,-3, and -9 in the cervix was evaluated using Western blot. RESULTS: MMP-2,-3, and -9 levels in the cervix under Conditions A and B were significantly lower than that under Condition C. CONCLUSIONS: These results suggest that the prevention of preterm delivery by rh-LF in a rabbit model has been achieved through inhibition of cervical maturation promoted by matrix metalloproteinase activity.

Reduction of connexin 43 in human cumulus cells yields good embryo competence during ICSI.

PURPOSE: The purpose of this study was to predict developmental competence of human oocytes during ICSI via analysis of connexin 43 (Cx43) in cumulus cells surrounding mature oocytes. MATERIALS AND METHODS: Human cumulus cells were manually separated from the oocyte-cumulus complex under a microscope. Cx43 mRNA was expressed by real-time quantitative polymerase chain reaction (RT-PCR) measurement in cumulus cells. RESULTS: There was no significant relationship between expression of Cx43 and fertilisation or cleavage rate. However, Cx43 expression was lower in the good morphology group (blastomeres>7 cells with fragmentation<10% on day 3) when compared to the other groups (p=0.035). CONCLUSIONS: These results suggest that full reduction of Cx43 expression on cumulus cells at the time of oocyte collection during ICSI is essential for developmental competence of human oocytes.

High concentrations of lactoferrin in the follicular fluid correlate with embryo quality during in vitro fertilization cycles.

OBJECTIVE: To investigate the level of lactoferrin (LF) in follicular fluid (FF), as well as the correlation between the LF concentration of FF, fertilization rate, and embryo quality. DESIGN: Retrospective study. SETTING: In vitro fertilization program at the Showa University School of Medicine, Tokyo, Japan. PATIENT(S): Follicular fluid was obtained from 35 IVF patients, aged 25-34 years. INTERVENTION(S): In total, 70 FF and serum samples were collected at the time of oocyte harvesting (44 of the oocytes were fertilized, and 26 were not). The LF concentration in FF was assayed via ELISA. RESULT(S): The mean LF concentration in FF of the fertilized group (500.2 +/- 35.5 ng/mL) was significantly higher than that in the unfertilized group (379.7 +/- 45.1 ng/mL). A positive correlation between follicular size and LF concentration was not found (r = 0.214). However, a high LF concentration in FF was indicative of good embryo quality. CONCLUSION(S): High LF concentrations in FF correlate with both a high fertilization rate and good embryo quality.

Concentration of lactoferrin and interleukin-6 in cervical mucus from patients being treated for infertility.

Background: The concentrations of the iron-binding protein lactoferrin (LF) and interleukin-6 (IL-6) were measured in the cervical mucus of patients being treated for infertility throughout the menstrual cycle. Methods: A total of 251 cervical mucus samples were obtained from the patients throughout the menstrual cycle. One hundred and fifty samples were from primary infertility patients with unexplained infertility and 101 samples were from secondary infertility patients as a control. The concentrations of LF and IL-6 were measured by enzyme immunoassays. The standard curve of LF concentrations ranged from 1.6 to 50 ng/mL. Results: The mean LF and IL-6 concentrations in the cervical mucus of primary infertility patients were higher than that of the control patients (P= 0.04, P= 0.032, respectively) The LF and IL-6 concentrations were highly correlated (P < 0.0001). Conclusion: Elevated levels of IL-6 and LF in the cervical mucus were obtained from primary infertility patients. We speculate that LF might also be one of the causes of infertility and might play an important role in reproductive processes in the cervix. (Reprod Med Biol 2006; 5: 105-109).

Recombinant human lactoferrin has preventive effects on lipopolysaccharide-induced preterm delivery and production of inflammatory cytokines in mice.

OBJECTIVE: The following animal studies have been conducted to investigate whether recombinant human lactoferrin (rh-LF) has the same effect as bovine lactoferrin (b-LF) in the prevention of preterm delivery. STUDY DESIGN: Female C3H/HeNCrj mice were pair-mated with male Crj:B6D2F1 mice. On day 15 of gestation, as a model of preterm delivery, a 50 microg/kg intraperitoneal injection of lipopolysaccharide (LPS) was administered twice with a 3-h interval between injections (2:00 and 5:00 PM). One hour prior to each LPS injection (1:00 and 4:00 PM), an intraperitoneal injection of saline, b-LF, or rh-LF (1 mg/body) was administered. In non-LPS-treated controls, an intraperitoneal injection of saline was administered 4 times (1:00, 2:00, 4:00 and 5:00 PM). Body weights and delivery times were recorded. To compare plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) between experimental and other pregnant mice, prepared as above, were sacrificed 6 h after the second LPS injection, and then blood samples were obtained and analyzed. RESULTS: Preterm delivery occurred (16.2+/-0.4 days of gestation) in all LPS-treated mice that were not administered LF. LF significantly prolonged gestation of LPS-treated mice: b-LF+LPS, 17.8+/-0.3 days; rh-LF+LPS, 18.0+/-0.8 days (P<0.05). LF (1 mg/body) significantly suppressed plasma IL-6 in LPS-treated mice:b-LF+LPS, 1060+/-154; rh-LF+ LPSF, 244+/-59; LPS without LF, 1628+/-115 pg/mL (P<0.05). As well, LF (1 mg/body) significantly suppressed plasma TNF-alpha in LPS-treated mice: b-LF+LPS, 88+/-36; rh-LF+LPS, 37+/-30; LPS without LF, 114+/-49 pg/mL (P<0.05). CONCLUSIONS: Rh-LF may prolong gestation in LPS-induced preterm delivery in mice, by suppressing LPS-induced plasma IL-6 and TNF-alpha augmentation.

Preventive effect of recombinant human lactoferrin in a rabbit preterm delivery model.

OBJECTIVE: Lactoferrin, an iron-binding glycoprotein found in cervical mucus and amniotic fluid, plays a defensive role against mucosal infections. This study examined the effect of recombinant human lactoferrin on preterm delivery in a rabbit model. STUDY DESIGN: Anesthetized rabbits were randomly assigned to receive either inoculation with Escherichia coli or saline solution and to receive treatment with or without recombinant human lactoferrin inserted into the cervix 2 hours before bacterial inoculation (condition A: saline + saline; condition B: E coli + saline; condition C: E coli + recombinant human lactoferrin). E coli , saline solution, and recombinant human lactoferrin were inserted into the cervix using a hysteroscope and a sterile polyethylene cannula. Fetus survival rate and days to delivery after inoculation were monitored and tumor necrosis factor-alpha concentrations were measured in maternal serum and amniotic fluid. RESULTS: Fetus survival for conditions A, B, and C were 95.7%, 0%, and 32.6%, respectively, whereas pregnancy continuation was 7.00 +/- 0 days, 3.25 +/- 0.43 days, and 4.85 +/- 1.77 days, respectively. CONCLUSION: Cervical recombinant human lactoferrin administration increased fetal survival and extended pregnancy. Lactoferrin has an anti-inflammatory action as well as an antibacterial action, suggesting that recombinant human lactoferrin has the potential to prevent preterm delivery originating from cervical infection in the clinical setting.