A novel model of sensorineural hearing loss induced by repeated exposure to moderate noise in mice: the preventive effect of resveratrol

Sensorineural hearing loss (SNHL) induced by noise has increased in recent years due to personal headphone use and noisy urban environments. The study shows a novel model of gradually progressive SNHL induced by repeated exposure to moderate noise (8-kHz octave band noise, 90-dB sound pressure level) for 1 hr exposure per day in BALB/cCr mice. The results showed that the repeated exposure led to gradually progressive SNHL, which was dependent on the number of exposures, and resulted in permanent hearing loss after 5 exposures. Repeated exposure to noise causes a loss of synapses between the inner hair cells and the peripheral terminals of the auditory nerve fibers. Additionally, there is a reduction in the expression levels of c-fos and Arc, both of which are indicators of cochlear nerve responses to noise exposure. Oral administration of resveratrol (RSV, 50 mg/kg/day) during the noise exposure period significantly prevented the noise exposure-induced synapse loss and SNHL. Furthermore, the study found that RSV treatment prevented the noise-induced increase in the gene expression levels of the proinflammatory cytokine interleukin-1β in the cochlea. These results demonstrated the potential usefulness of RSV in preventing noise-induced SNHL in the animal model established as gradually progressive SNHL.

Prophylactic administration of human amniotic fluid stem cells suppresses inflammation-induced preterm birth via macrophage polarization

Ascending inflammation from the vagina is a major cause of preterm birth. Currently, this condition-especially when uncontrolled-has no effective treatment. Human amniotic fluid stem cells (hAFSCs) are mesenchymal stem cells known to exert potent anti-inflammatory effects in animal models of perinatal diseases, such as periventricular leukomalacia, myelomeningocele, and neonatal sepsis. However, hAFSC therapy for inflammation-induced preterm birth has not been tested. In order to determine the therapeutic effect of hAFSC transplantation, we employed a preterm mouse model of ascending infection; this model was constructed by administering lipopolysaccharide to pregnant mice. We investigated the preterm birth rate and evaluated the inflammation of tissues, which is related to progressive infections, such as those involving the cervix, placenta, and lavage cells, using real-time qPCR. Further, we tracked the fluorescence of fluorescently labeled hAFSCs using an in vivo imaging system, and hAFSC aggregation was evaluated using immunohistochemistry analysis. We also investigated the presence of multiple types of peritoneal macrophages via flow cytometry analysis. Finally, we performed sphere culturing and co-culturing to determine the therapeutic effects of hAFSCs, such as their anti-inflammatory effects and their potential to alter macrophage polarization. We found that hAFSC administration to the peritoneal cavity significantly reduced inflammation-induced preterm birth in the mouse model. The treatment also significantly suppressed inflammation of the placenta and cervix. Transplanted hAFSCs may have aggregated with peritoneal macrophages, switching them from an inflammatory to an anti-inflammatory type. This property has been reported in vivo previously, but here, we examined the effect in vitro. Our findings support the hypothesis that hAFSCs suppress inflammation and reduce preterm birth by switching macrophage polarity. This study is the first to demonstrate that hAFSCs are effective in the treatment and prevention of inflammation-induced preterm birth.

Effect of Resveratrol on Pregnancy, Prenatal Complications and Pregnancy-Associated Structure Alterations

Adverse pregnancy outcomes are considered significant health risks for pregnant women and their offspring during pregnancy and throughout their lifespan. These outcomes lead to a perturbated in-utero environment that impacts critical phases of the fetus's life and correlates to an increased risk of chronic pathological conditions, such as diabetes, obesity, and cardiovascular diseases, in both the mother's and adult offspring's life. The dietary intake of naturally occurring antioxidants promotes health benefits and disease prevention. In this regard, maternal dietary intake of polyphenolic antioxidants is linked to a reduced risk of maternal obesity and cardio-metabolic disorders, positively affecting both the fetus and offspring. In this work, we will gather and critically appraise the current literature highlighting the effect/s of the naturally occurring polyphenol antioxidant resveratrol on oxidative stress, inflammation, and other molecular and physiological phenomena associated with pregnancy and pregnancy conditions, such as gestational diabetes, preeclampsia, and preterm labor. The resveratrol impact on prenatal complications and pregnancy-associated structures, such as the fetus and placenta, will also be discussed. Finally, we will draw conclusions from the current knowledge and provide future perspectives on potentially exploiting resveratrol as a therapeutic tool in pregnancy-associated conditions.

Preterm Birth Therapies to Target Inflammation

Preterm birth (PTB; defined as delivery before 37 weeks of pregnancy) is the leading cause of morbidity and mortality in infants and children aged <5 years, conferring potentially devastating short‐ and long‐term complications. Despite extensive research in the field, there is currently a paucity of medications available for PTB prevention and treatment. Over the past few decades, inflammation in gestational tissues has emerged at the forefront of PTB pathophysiology. Even in the absence of infection, inflammation alone can prematurely activate the main components of parturition resulting in uterine contractions, cervical ripening and dilatation, membrane rupture, and subsequent PTB. Mechanistic studies have identified critical elements of the complex inflammatory molecular pathways involved in PTB. Here, we discuss therapeutic options that target such key mediators with an aim to prevent, postpone, or treat PTB. We provide an overview of more traditional therapies that are currently used or being tested in humans, and we highlight recent advances in preclinical studies introducing novel approaches with therapeutic potential. We conclude that urgent collaborative action is required to address the unmet need of developing effective strategies to tackle the challenge of PTB and its complications.

Uncaria tomentosa extract (AC-11) improves pregnancy hypertension together with suppression of sFlt-1 and sEng

Disruption of well-controlled reproductive functions leads to pregnancy complications such as hypertensive disorders of pregnancy (HDP). Uncaria tomentosa (Wild), known as cat's claw, is widely used for the treatment of a various types of health problems; AC-11 (AC-11®, hot-water extract of U. tomentosa) is unique phytochemical compound and has potential roles as anti-inflammatory or anti-oxidant processes. We investigated whether AC-11 has a protective effect on pathogenesis of HDP in vivo and production of anti-angiogenic factors (sFlt-1 and sEng, major factors for the onset of HDP) in in vitro. Non-pregnant or pregnant mice were administered AC-11 (4 mg/mL), then, angiotensin II (Ang II) was subcutaneously infused to increase blood pressure. Human placental tissues or human umbilical vein endothelial cells (HUVECs) were incubated with or without AC-11. Treatment with AC-11 significantly reduced blood pressure induced by Ang II infusion. The population of CD8⁺T cells, the ratio of CD8/CD4, and plasma interleukin-6 levels were increased by Ang II infusion, and were decreased by AC-11 both in pregnant and non-pregnant mice. In pregnant mice, plasma levels of sFlt-1 and sEng were decreased by AC-11. In in vitro cell culture of HUVECs or placental tissue culture, treatment with AC-11 significantly inhibited secretion of sFlt-1 and sEng. We suggest a novel role of AC-11 in regulating blood pressure by controlling the balance of T cell population and inflammatory cytokine production both in non-pregnant and pregnant conditions. In addition, AC-11 inhibits HDP-related factors, including sFlt-1 and sEng, suggesting that AC-11 may useful for relieving HDP.

Resveratrol prevents ISO-induced myocardial remodeling associated with regulating polarization of macrophages through VEGF-B/AMPK/NF-kB pathway

Macrophage expansion and inflammatory responses are involved in induction of cardiac remodeling. Resveratrol has strong anti-inflammatory effects, however its effect on macrophage infiltration and polarization is unknown. This study aimed to investigate the anti-inflammatory effects of RSV on ISO-induced myocardial remodeling in mice and its regulatory role in macrophage polarization. BALB/c mice were orally administered with RSV (100 mg/kg) daily for one week, then were subcutaneously injected with ISO (50 mg/kg) daily for another week. ISO injections to mouse caused cardiac dysfunction evidenced by cardiac hypertrophy and cardiomyocyte fibrosis. Meanwhile, macrophage M1 polarization was found in ISO treated mice, which was evidenced by increased percentage of Ly6C^low macrophages in the heart, levels of M1 cytokines and expression of CD68, and decreased percentage of Ly6C^high macrophage, levels of M2 cytokines and expression of CD206. All these changes in cardiac and macrophage M1 polarization were ameliorated when mice were pretreated with RSV. The effect of RSV on macrophage polarization was also tested in RAW264.7 cells. It was found that pre-treatment with RSV decreased the levels of M1 marker or proinflammatory cytokines, while increased the levels of M2 markers in ISO treated cells. In addition, it was found that RSV could upregulate the expression of VEGF-B and the activity of AMPK, while it downregulated the expression of phosphorylated NF-κB p65 both in RAW264.7 cells and in mice. Furthermore, pretreatment with VEGF-B siRNA greatly reversed changes in almost all above parameters evoked by RSV in RAW264.7 cells. Therefore, our findings suggest RSV has potential therapeutic effects in ISO-induced myocardial injury, which may be by inhibiting the M1 polarization of macrophages through VEGFB/AMPK/NF-кB pathway.

Experimental drugs for the inhibition of preterm labor

INTRODUCTION

Preterm birth is the leading cause of neonatal morbidity and mortality globally and poses a substantial economic burden. Consequently, there is a need for the identification of therapeutic targets and novel experimental drugs for the inhibition of preterm labor to improve neonatal outcomes.

AREAS COVERED

The authors review the pathophysiology of labor and the inflammatory pathways underpinning it. The interruption of these pathways forms the basis of therapeutic targets to inhibit preterm labor. Current drugs available for the treatment of preterm labor are reviewed, followed by experimental drugs including toll-like receptor 4 (TLR-4) antagonists, cytokine suppressive anti-inflammatory drugs (CSAIDs), N-acetyl cysteine (NAC), Sulfasalazine (SSZ), tumor necrosis factor-alpha (TNF-α) antagonists, interleukin-1 receptor (IL-1) inhibitors, omega-3 polyunsaturated fatty acids and lipid metabolites, and the polyphenols.

EXPERT OPINION

A number of new therapeutic strategies for the prevention of preterm labor are being investigated. These have the potential to improve neurodevelopmental outcomes and survival in babies born preterm, reducing the economic and healthcare costs of caring for the complex needs of these children in the immediate and long term. It is likely that over the next decade there will be a new treatment option that targets the pathological inflammatory processes involved in preterm labor.

ASK1 promotes uterine inflammation leading to pathological preterm birth

It is widely accepted that enhanced uterine inflammation associated with microbial infection is a main causative factor for preterm birth. However, little is known about the molecular basis by which inflammation is associated with preterm birth. Here, we demonstrate that apoptosis signal-regulating kinase 1 (ASK1), a member of the mitogen-activated protein 3-kinase family, facilitates inflammation-induced preterm birth and that inhibition of ASK1 activity is sufficient to suppress preterm birth. ASK1-deficient pregnant mice exhibited reduced incidence of lipopolysaccharide (LPS)-induced preterm birth. ASK1 was required for the induction of LPS-induced inflammatory responses related to preterm birth, including pro-inflammatory cytokine production in the uterus and peritoneal cavities. In addition, selective suppression of uterine ASK1 activity through a chemical genetic approach reduced the incidence of LPS-induced preterm birth. Moreover, translational studies with human choriodecidua demonstrated that ASK1 was required for LPS-induced activation of JNK and p38 and pro-inflammatory cytokine production. Our findings suggest that ASK1 activation is responsible for the induction of inflammation that leads to preterm birth and that the blockade of ASK1 signaling might be a promising therapeutic target for preventing preterm birth.

Systematic review: Impact of resveratrol exposure during pregnancy on maternal and fetal outcomes in animal models of human pregnancy complications-Are we ready for the clinic?

Resveratrol (RSV) has been reported to have potential beneficial effects in the complicated pregnancy. Various pregnancy complications lead to a suboptimal in utero environment that impacts fetal growth during critical windows of development. Detrimental structural changes to key organ systems in utero persist into adult life and predispose offspring to an increased risk of chronic non-communicable metabolic diseases such as cardiovascular disease, diabetes and obesity. The aim of this systematic review was to determine the effect of gestational RSV exposure on both maternal and fetal outcomes. Publicly available databases (n = 8) were searched for original studies reporting maternal and/or fetal outcomes after RSV exposure during pregnancy irrespective of species. Of the 115 studies screened, 31 studies were included in this review. RSV exposure occurred for different durations across a range of species (Rats n = 18, Mice n = 7, Japanese Macaques n = 3 and Sheep n = 3), models of complicated pregnancy (eg. maternal dietary manipulations, gestational diabetes, maternal hypoxia, teratogen exposure, etc.), dosages and administration routes. Maternal and fetal outcomes differed not only based on the model of complicated pregnancy assessed but also as a result of species. Given the heterogenic nature of these studies, further investigation assessing RSV exposure during the complicated pregnancy is warranted. In order to make an informed decision regarding the use of RSV to intervene in pregnancy complications, we suggest a minimum data set for consideration in future studies.

Inflammation-Induced Adverse Pregnancy and Neonatal Outcomes Can Be Improved by the Immunomodulatory Peptide Exendin-4

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide. Inflammation is causally linked to preterm birth; therefore, finding an intervention that dampens maternal and fetal inflammatory responses may provide a new strategy to prevent adverse pregnancy and neonatal outcomes. Using animal models of systemic maternal inflammation [intraperitoneal injection of lipopolysaccharide (LPS)] and fetal inflammation (intra-amniotic administration of LPS), we found that (1) systemic inflammation induced adverse pregnancy and neonatal outcomes by causing a severe maternal cytokine storm and a mild fetal cytokine response; (2) fetal inflammation induced adverse pregnancy and neonatal outcomes by causing a mild maternal cytokine response and a severe fetal cytokine storm; (3) exendin-4 (Ex4) treatment of dams with systemic inflammation or fetal inflammation improved adverse pregnancy outcomes by modestly reducing the rate of preterm birth; (4) Ex4 treatment of dams with systemic, but not local, inflammation considerably improved neonatal outcomes, and such neonates continued to thrive; (5) systemic inflammation facilitated the diffusion of Ex4 through the uterus and the maternal-fetal interface; (6) neonates born to Ex4-treated dams with systemic inflammation displayed a similar cytokine profile to healthy control neonates; and (7) treatment with Ex4 had immunomodulatory effects by inducing an M2 macrophage polarization and increasing anti-inflammatory neutrophils, as well as suppressing the expansion of CD8+ regulatory T cells, in neonates born to dams with systemic inflammation. Collectively, these results provide evidence that dampening maternal systemic inflammation through novel interventions, such as Ex4, can improve the quality of life for neonates born to women with this clinical condition.

Resveratrol protects from lipopolysaccharide-induced inflammation in the uterus and prevents experimental preterm birth

STUDY QUESTION

Is resveratrol able to prevent the lipopolysaccharide (LPS)-induced preterm labor in 15-day pregnant BALB/c mice?

SUMMARY ANSWER

Resveratrol prevented the LPS-induced onset of preterm labor in 64% of the cases and showed anti-inflammatory and tocolytic effects by downregulating COX-2 and iNOS expression and NOS activity, and by changing the uterine prostaglandin and endocannabinoid profiling.

WHAT IS KNOWN ALREADY

Genital tract infections by Gram-negative bacteria are a common complication in human pregnancy and have been shown to increase risk of preterm delivery. Bacterial LPS elicits a strong maternal inflammatory response that results in preterm delivery and fetal death in a murine model endotoxin-induced preterm labor.

STUDY DESIGN, SIZE, DURATION

An in vivo animal study was conducted. On Day 15 of pregnancy, mice received at 8:00 h a dose of vehicle (40% ethanol in saline solution) or resveratrol (3 mg/kg in vehicle) via oral gavage followed by two doses of LPS or vehicle administered intraperitoneally (i.p.), the first one at 10:00 h (0.17 mg/kg in 0.1 ml of sterile saline solution) and the second at 13:00 h (0.5 mg/kg in 0.1 ml of sterile saline solution). The mice were closely observed for any signs of morbidity (piloerection, decreased movement, and diarrhea), vaginal bleeding or preterm delivery. The beginning of preterm delivery was defined by early delivery of the first pup. Normal term labor occurs on Day 19 of gestation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Time of labor, pregnancy outcome and morphological features were evaluated after LPS and/or resveratrol administration. Uterine stripes were collected 5 h after the last LPS injection and prostaglandin and endocannabinoid profiling was analyzed by mass spectrometry. Nitric oxide synthase (NOS) activity was measured by radioconversion assay. Cyclooxygenase-2 (Cox-2) and 15-hydroxyprostaglandin dehydrogenase (15-Pgdh) mRNA levels were analyzed by RT-PCR whilst the protein expression of inducible nitric oxide synthase (iNOS), COX-1 and COX-2 were studied by western blot.

MAIN RESULTS AND THE ROLE OF CHANCE

In vivo treatment of 15-day pregnant BALB/c mice with resveratrol prevented the LPS-induced preterm birth in 64% of the cases, whereas only 15% of mice with LPS alone escaped preterm birth. Treatment with resveratrol resulted in a reduced NOS activity (P < 0.05) in the uterus of LPS-treated mice. Similarly, resveratrol reduced the expression of LPS-induced pro-inflammatory agents such as iNOS (P < 0.05), COX-2 (P < 0.05), prostaglandin E2 (PGE2) (P < 0.05) and anandamide (AEA) (P < 0.05). Moreover, resveratrol administration resulted in changes in the uterine endocannabinoid profiling altered by LPS.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Since our experimental design involves the use of mice, the extrapolation of the results presented here to humans is limited.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide evidence for the tocolytic effects of resveratrol.

STUDY FUNDING AND COMPETING INTEREST(S)

Dr Ana María Franchi was funded by Agencia Nacional para la Promoción Científica y Tecnológica (PICT 2013/0097) and by Consejo Nacional de Investigaciones Científicas y Técnicas (PIP 2012/0061). Dr Heather B. Bradshaw was funded by NIH (DA006668). The authors have no competing interests.

Advanced glycation end products and lipopolysaccharides stimulate interleukin-6 secretion via the RAGE/TLR4-NF-κB-ROS pathways and resveratrol attenuates these inflammatory responses in mouse macrophages

Macrophages are essential for regulating the physiology of pregnancy; however, excessive inflammatory responses to macrophages, induced by infection and/or endogenous danger signals, may potentially result in complications during pregnancy. Advanced glycation end-products (AGE) and lipopolysaccharides (LPS) are known to induce inflammation and are associated with adverse developmental outcomes. The aim of the present study was to examine the effect of AGE and LPS on cytokines in the J774 murine macrophage cell line and the potential effect of resveratrol on AGE- and LPS-induced inflammation in macrophages. AGE and LPS significantly increased IL-6 mRNA expression and secretion in J774 macrophages (P<0.05). Although AGE and LPS significantly stimulated IL-1β mRNA expression (P<0.05), they had no significant effect on IL-1β secretion. To assess the receptors for AGE and LPS, including receptor for AGE (RAGE) and Toll-like receptor (TLR4), blocking reagents (RAGE antagonist or TLR4 inhibitor) were added to the J774 macrophages. IL-6 secretion induced by AGE or LPS was significantly inhibited by pretreatment with RAGE antagonist (P<0.05) or TLR4 inhibitor (P<0.05). IL-6 secretion was dependent on nuclear factor (NF)-κB activation and the production of reactive oxygen species (ROS; P<0.05). Resveratrol suppressed mRNA expression and intracellular IL-6 production, resulting in significantly decreased IL-6 secretion after treatment with LPS or AGE (P<0.01). Furthermore, treatment with Ex527, which is a sirtuin-1 (SIRT1) inhibitor, significantly attenuated the anti-inflammatory effect of resveratrol (P<0.05), and treatment with 5-aminoimidazole-4-carboxamide ribonucleotide, which is a 5' adenosine monophosphate-activated protein kinase (AMPK) activator, resulted in a significant decrease in IL-6 secretion in J774 macrophages (P<0.05). The results of the present study indicated that AGE and LPS increase IL-6 secretion depending on NF-κB activation and ROS production through RAGE and/or TLR4 in the J774 murine macrophage cell line. Based on the present study, resveratrol appears to be an effective regulator of the inflammatory responses associated with SIRT1 and AMPK activation in macrophages. These results suggest that resveratrol may have therapeutic applications for controlling immune responses during pregnancy.

A Role for the Inflammasome in Spontaneous Labor at Term with Acute Histologic Chorioamnionitis

Inflammasomes are cytosolic signaling platforms that regulate the activation of caspase (CASP)-1, which induces the maturation of interleukin (IL)-1β and IL-18. Herein, we determined whether the chorioamniotic membranes from women in spontaneous labor at term with acute histologic chorioamnionitis express major inflammasome components and whether these changes are associated with the activation of CASP-1 and CASP-4 and the release of mature IL-1β and IL-18. When comparing the chorioamniotic membranes from women in spontaneous labor at term with acute histologic chorioamnionitis to those without this placental lesion, we found that (1) the messenger RNA (mRNA) abundance of NLR family pyrin domain containing 3 ( NLRP3), NLR family CARD domain containing 4 ( NLRC4), absent in melanoma 2 ( AIM2), and nucleotide binding oligomerization domain 2 ( NOD2) was higher; (2) the NLRP3 and NLRC4 protein quantities were increased; (3) the mRNA and protein expressions of CASP-1 and its active forms were greater; (4) CASP-4 was increased at the mRNA level only; (5) the mRNA and protein expressions of IL-1β and its mature form were higher; and (6) a modest increase in the total protein concentration and abundance of the mature form of IL-18 was observed. In vitro incubation of the chorioamniotic membranes with the CASP-1 inhibitor, VX765, decreased the release of endotoxin-induced IL-1β and IL-18 (2-fold) but not IL-6 or tumor necrosis factor α. In conclusion, spontaneous labor at term with acute histologic chorioamnionitis is characterized by an upregulation of inflammasome components which, in turn, may participate in the activation of CASP-1 and lead to the release of mature IL-1β by the chorioamniotic membranes. These results support a role for the inflammasome in the mechanisms responsible for spontaneous labor at term with acute histologic chorioamnionitis.