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The ongoing research focuses on exploring the potential of Careya arborea (CA) fiber, banana fiber (BF), and epoxy composites as sustainable alternatives to petroleum-based products and synthetic fibers. The aim is to enhance the interfacial bonding and overall performance of these composites while reducing reliance on traditional materials. The study investigates the adhesion between CA fiber, BF (both chemically treated), and epoxy with polylactic acid (PLA) coating. Specifically, it examined how the PLA coating affects the mechanical properties, including tensile strength, flexural strength, impact resistance, and water absorption behavior, of the fabricated composites. Mechanical characterizations of the composite specimens are conducted following ASTM standards. The PLA-coated and NaOH-treated specimens significantly improved their tensile strength (20.56%) and flexural strength (16.7%), and significantly reduced their water absorption capacity (by 47.6%) compared to the untreated ones. These findings highlight the promise of using treated natural fibers and PLA coatings to create more sustainable and high-performance composite materials.

Plasticizers improve polymeric materials' properties and processability as additives. Currently, a variety of liquid synthetic plasticizers derived from fossil fuels are available. The environmental unsuitability of these materials could potentially lead to adverse effects on the environment. When we compare solid and liquid plasticizers, we find an infinite variety of liquid plasticizers. As a result, our work focuses on the extraction of plasticizer from plant sources. Accordingly, the plasticizer is extracted from eucalyptus leaves via solvent purification and surface catalysis. Research was conducted utilizing X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Ultraviolet (UV) visible spectroscopy to determine the characteristics of plasticizer. The scanning electron microscopy (SEM) and energy dispersive spectrum (EDS) analysis are used to analyze the surface morphology of the isolated plasticizer. The plasticizer's UV examination reveals active absorption at 375.21 nm. The plasticizer was determined to have a lower density of 0.941 g/cm3. The plasticizer that was extracted had a low solubility in water and organic solvents while possessing an estimated molecular weight of 340. The glass transition temperature of plasticizer was also examined using differential scanning electron microscopy analysis and found to be 64.17 °C. The crystallinity index and size were found to be 34.08 % and 28.57 nm, respectively. The characteristic features obtained were well-suited for use as filler in polymer composite materials.

Acacia concinna is a climber shrub commonly found in the warm plains of central and south India, and it is an excellent herbal remedy for hair. In this investigation, fiber has been extracted from the stem portion of the Acacia concinna plant through the retting process; subsequently, the fibers were cut into 40 mm length. A part of extracted fibers were treated with 3% alkali concentration, and the remaining was kept as an untreated form. Composites were fabricated with raw and treated Acacia concinna fibers separately using a compression moudling process. During composite fabrication, five different fiber weight fraction was maintained, such as 10%, 20%, 30%, 40%, and 50%. Tensile, flexural, impact, hardness, moisture diffusion, and thermal properties were analyzed on the alkali-treated, and untreated fiber reinforced composites. The alkali-treated composite with 30% fiber weight fraction showed good tensile strength (129.38 ± 5.3 MPa), tensile modulus (1.986 GPa), flexural strength (137.31 MPa), flexural modulus (2.86 GPa), impact property (18.61 J/cm2), hardness property (95 HRRW) and water absorption characteristics (4.9%). SEM analysis confirms the improved surface of the alkali-treated composite material.

The physicochemical, thermal, and surface morphological properties of the Sida mysorensis fiber (SMF) were investigated first time in this article. From the chemical compositional analysis, higher cellulose (53.36 wt. %) and lower hemicelluloses (15.23 wt. %), lignin (9.46 wt. %), wax (0.86 wt), and ash content of (3.33 wt. %) SMF were acknowledged. The different functional groups of SMF were determined through the Fourier transform infrared spectrometer. The Crystallinity index (41.17%) and crystalline size (13.06 nm) of SMF were evidenced through the X-ray diffraction analysis. Atomic force microscopy investigation was used to study the surface morphology of SMF. Thermal stability (220°C) and kinetic activation energy (65.486 KJ/mol) of the SMF were determined through the thermogravimetric analysis. All the above findings ensured that SMF can be used as reinforcement in polymer composite.

The present work is planned to investigate the fundamental properties of the novel plant fiber extracted from the bark of Acacia nilotica L. tree. The various chemical compositions of the Acacia nilotica L. fiber (ANF) such as cellulose (56.46 wt. %), hemicelluloses (14.14 wt. %), lignin (8.33 wt. %) and ash content (4.95 wt. %) were identified through the chemical analysis. The maximum degradation temperature of ANF (339°C) was determined by the thermogravimetric analysis. The crystallinity index (44.82%) and crystalline size (3.21 nm) of the ANF were calculated by the X-ray diffraction analysis. The surface topography of ANF was estimated through the atomic force microscope. The density of ANF was identified as a value of 1165 kg/m3 which is comparatively lower than the other renowned fibers such as Acacia leucophloea (1385 kg/m3) and Jute (1460 kg/m3); this would be confirmed with all above characterization results that is an appropriate material to fabricate the green composites.

This investigation aimed at finding the effect of weight fraction (10 wt.%, 20 wt.% and 30 wt.%) and fiber orientation (0°, 45° and 90°) on mechanical properties (Tensile, Flexural and Impact) of Carica papaya fiber/epoxy (CPFE) composite. Totally nine composite samples were fabricated by hand layup followed by compression molding method. Testing results revealed that composites containing 20 wt.% and 0° fiber orientation exhibited better mechanical properties such as tensile strength (122 MPa), flexural strength (118.9 MPa) and impact strength (7.8 J) when compared to composite samples with other weight fraction and orientation. The scanning electron microscope (SEM) analysis was used to analyze the fractured surfaces of the composite specimens. The thermal stability of CPFE composites was evaluated by the Thermo Gravimetric (TG) and Differential Thermo Gravimetric (DTG) curves. All the findings led to the conclusion that the CPFE composites are suitable material to make the light weight industrial applications.

To overcome the environmental regulations adopted across the globe in polymer composites, a natural fiber extracted from the waste stem of Elettaria cardamomum plant (ECF) was investigated for its suitability in polymer composites. Fundamental properties such as chemical, physical, thermal and surface morphology of ECF were evaluated using chemical composition analysis, optical microscope test, X-ray diffraction, Thermo-gravimetric and scanning electron microscope analysis. The chemical analysis outcomes revealed that ECF has a comparatively higher amount of cellulose (63.12 wt. %), lignin (16.5 wt. %) and lower hemicelluloses (13.7 wt. %), wax (1.5 wt. %) which is expected property of a reinforcement. Thermal analysis results demonstrated that ECF has thermal stability (up to 230°C). Surface morphological analysis showed that non-cellulosic materials and impurities existed on the surface of the ECF. So, mild surface treatment was recommended. Higher tensile strength (294 ± 1.62 MPa) and lower density (1470 Kg/m3) of ECF defined this as an appropriate fiber for reinforced composites.

In this work, graphene was used as a filler for banyan aerial root fibers reinforced epoxy composites at various compositions. The synergetic effect of graphene and banyan fibers, on the physical and mechanical characteristics of the epoxy thermoset, was studied. The mechanical tests, hardness, water absorption behavior and morphology of the composites were studied. Significant improvement in tensile strength, flexural strength, shore D hardness and substantial reduction in the percentage of water absorption was observed. This paper also discusses the ideal proportion of banyan fibers with graphene powder for the development of the improved epoxy composites. The optimum concentration of the composites was observed at 4% of graphene powder in the 40% banyan fiber-reinforced hybrid epoxy composites. From the results, it is proved that graphene combined with 40% banyan fiber-reinforced epoxy hybrid composites will efficiently improve the strength of the composites.

This study was aimed at understanding the characteristics of Celosia argentea fiber (CAF) and its physicochemical properties. The physicochemical properties of CAF were analyzed by FT-IR, XRD, TGA, SEM, and AFM analysis. Cellulose content (64.34wt.%), density (843 kg/m3) and crystallinity index (52.54%) properties were identified in the CAF while the thermal studies performed by TG and DTG technique revealed that the maximum degradation temperature is 324°C with a kinetic activation energy of 61.393 kJ/mol. From the results, it is evident that the CAF could be one of the future reinforcement materials for green composites applications.

The present environmental regulations enforced by the government authorities have made the investigators around the globe to make use of more and more green materials particularly in composite systems. In this context, natural fibers play an important role and proven to be excellent reinforcements in polymer matrices. However, these natural fibers have got one major limitation: their incompatible hydrophilic behavior which affects their bonding with hydrophobic matrixes. Researchers over the years have come up with several fiber surface modification processes to overcome this defect. So, in this present study, the effect of various chemical treatments like alkaline, benzoyl peroxide, potassium permanganate, and stearic acid on Prosopis juliflora fibers has been discussed. These various chemical treatments on the fiber surfaces impacted on their structure, composition, and properties which were discovered through chemical analysis, Fourier transform-infrared, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and tensile testing.

This work examines the effects of processing parameters such as pressure and temperature on the tensile properties of plain woven jute fabric reinforced recycled polypropylene composite. The main objective of this study is to the utilization of recycled polypropylene in a better way. By recycling of this polypropylene will reduce the environmental impacts and preparation of composites by this recyclable plastic can be used for various applications. In this study, eight different composite laminates under varying pressure (1, 2, 3, 4 MPa) and temperature (190, 210, 230, 250 °C) were produced and they were found to have similar fiber weight fractions up to 62%. Tensile tests were carried out on these composites to optimize the processing parameters. From the static tensile, the various test specimens exposed that the variation in temperature and pressure levels during the performance have a significant effect on the tensile properties of the bio-composites. Keywords: Jute fabrics, Recycled PP, Laminated composites, Processing parameters, Tensile testing

Natural fiber polymer matrix composites occupy the major percentage in applications due to its ecofriendly and low-cost nature. This study investigates the mechanical properties of a polyester matrix nanocomposite reinforced by the NaOH-treated jute fabric mat (NJM) and untreated jute fabric mat (UJM). In addition, the effects of egg shell powder (ESP) and nanoclay (NC) to the above has also been studied. The matrices were prepared with different combinations of presence and absence of the ESP, NC, and both as well as different weight percentage using compression molding process. The mechanical and morphological properties of the composites were determined. The tensile strength, flexural strength, and impact strength of NJM with NC 1.5%wt and ESP 1.5%wt were found to be 29.28 MPa, 39.51 MPa and impact strength 3.03 J, respectively. This composition is superior to the other compositions. Morphological analysis of tensile fractured surface showed interfacial adhesion between UJM and NJM composites. NJM composites contained smaller amount of pullouts and the splits compared with the UJM composites, which hold up the better performance.

Composites were fabricated from Ramie cellulose microfibrils (RCMF) with cassava starch as matrix and glycerol as a plasticizer. Different composites were fabricated with microfibrils loadings of 0, 2, 4, 8, and 10 wt%. The Particle Size Analyzer results show the average size of RCMF as 1.573 μm. The addition of RCMF considerably influenced the physical, crystalline, thermal, and tensile properties of composites. The addition of RCMF enhanced the crystallinity index (CI) from 32% to 36.67%. Thermogravimetric analysis and tensile test results showed improvement in thermal stability and tensile strength of composite up to 6 wt% microfibrils addition.

Environmental friendly products are getting much attention nowadays because of their availability in abundance and their usability in many engineering applications. Natural fibers possess many unique properties which make them easily replaceable to man-made fibers. This review is envisioned to present the various extraction and chemical treatment methods and also focused on providing the information of the fibers in terms of their physical and chemical properties.

The present investigation aimed to understand the physicochemical properties of new natural fiber extracted from Albizia amara (AA) bark. The chemical composition and structural, thermal, and tensile properties of AA fibers (AAFs) were investigated. The results indicated that AAF had crystallinity index of 63.78%, cellulose of 64.54 wt%, hemicellulose of 14.32 wt%, lignin of 15.61 wt%, and low density of 1043 kg/m3. Thermogravimetric analysis shows that AAFs were thermally stable up to 330.6°C and the functional groups of the AAFs were identified by Fourier transform infrared analysis. The AAFs exhibited tensile strength of 640 ± 13.4 MPa with strain rate of 1.57 ± 0.04%. This investigation reveals that AAFs could be a suitable material as reinforce agent in natural fiber–polymer composites for different applications.

Characterization of new natural fibres from various parts of plants have become increasingly popular not only in textile industries, automotive sector, electrical applications, and construction industries, but in various industrial applications because of their versatile characteristics, availability, biodegradability and providing sustainable solutions to support technical innovation. This study aimed to determine the characterization and physicochemical properties of Phaseolus vulgaris fibers (PVF) by Thermo gravimetric analysis (TGA)/DTG, X-Ray Diffraction analysis (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Eventually, fourier transform analysis and XRD analysis of PVFs demonstrated the presence of cellulose with a crystallinity index of 43.01%. The surface morphological analysis was observed and reveals that PVFs contain rougher surfaces, which would be favourable to develop good bonding with the matrix for making composites.

Natural fiber-reinforced polymer composites (NRPCs) are replacing many synthetic fibers because of their cheap availability and their hygienic, ecological, biodegradable, and sustainable properties. This work involved extraction of new cellulosic fibers from red banana peduncle (RBP) plant and investigated its chemical composition, physical, structural, thermal, and tensile properties. RBP fibers (RBPFs) have high specific strength and good binding properties due to their light weight andpresence of high cellulose (72.9 wt%), low lignin (10.01 wt%), and wax (0.32 wt%). X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) determined that RBPFs are rich in cellulose content with a crystallinity index (CI) of 72.3%. The density and diameter of the fibers were found to be about 0.896 g/cm3 and 15–250 μm, respectively. The fiber was thermally stable up to 230°C. Based on the results of this work, it seems that the properties of the fiber are a suitable candidate as a natural reinforcing material for the development of the biocomposite for potential applications.

This research has been carried out to find better hybrid natural/glass fiber-reinforced composites for engineering applications. This research work studied the impact and inter-laminar strength of E-glass with jute/kenaf woven fabric epoxy composites with the aim of evaluating the hybridization effects on different laminate stacking sequences made with jute, kenaf, and E-glass fabrics by the vacuum bagging method. All the laminates were prepared in 300 × 300 mm2 with a total of five plies maintained at 3 mm thickness, by varying the number and position of jute, kenaf, glass layers so as to obtain nine different stacking sequences. Among them, one group of all pure jute, pure kenaf, and pure E-glass laminates were also fabricated for comparison purpose. The specimen preparation and testing were carried out as per ASTM standards. From the results, it is shown that the properties of jute/kenaf fabrics-reinforced epoxy composites can be enhanced by hybridization with the addition of glass fabrics. The hybridization of jute/kenaf fabrics with E-glass fabrics provides a method to improve the mechanical impact and inter-laminar strength over pure natural fiber-reinforced composites. The hybrid laminate having E-glass and kenaf fiber plies as skin layers and jute fiber plies as core layers showed better properties compared to other laminates.

The natural fiber Epipremnum aureum was extracted from its plant. E. aureum fibers (EAFs) were investigated by chemical analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and single fiber tensile test. Chemical analysis, FTIR, and X-ray analysis evidenced that these fibers has 66.34% cellulose content with crystallinity index of 49.33%. The thermogravimetric analysis reveals that EAFs can thermally withstand temperatures until 328.9°C. The morphology of the EAFs was observed by scanning electron microscope. It was established that the fiber can be utilized as reinforcement in polymer composites.

Owing to their low weight-to-high strength ratio and recyclable features, the natural fibers are the most potential choice in place of synthetic fibers and been used as reinforcement materials in polymer matrix composites. Characterization of Ceiba pentandra bark fibers (CPFs) such chemical analysis, Fourier Transform-Infrared Analysis (FTIR), X-ray diffraction, thermogravimetric analysis, and Differential thermogravimetric analysis (DTG) analysis has analyzed. CPFs contain 60.9% (w/w) of cellulose, 17.5% (w/w) of hemicellulose, and 23.5% (w/w) of lignin. Besides, its density and crystallinity index are 682 kg m−3 and 57.94%, respectively. TG and DTG analysis discovered that CPFs are thermally stable up to 342.1°C. Further, all the resources of CPFs ensured that it can be an excellent alternative for synthetic fibers in polymer matrix composites.

Natural fibers are the one worthy substitute for replacing synthetic fibers and used as a polymer reinforcement due to their eco-friendly nature. This investigation deals with the newly identified Sida cordifolia fibers (SCFs) characterized by chemical analysis, single fiber tensile test, thermogravimetric analysis (TGA/DTG), Fourier transform-infrared spectroscopy (FT-IR) analysis, X-ray diffraction (XRD), and atomic force microscopy (AFM). The chemical constituents of SCFs contains cellulose (69.52%), hemicellulose (17.63%), and lignin (18.02. %). The SCFs are thermally stable up to a temperature of 338.2°C evidenced by TGA analysis. The X-ray diffraction confirmed that SCFs were rich in cellulose fraction with a crystallinity index of 56.92%.

Natural swollen finger grass fibers being novel are botanically known as “Chloris barbata fibers (CBFs)” and are selected for this study in order to understand their morphological properties. The CBF has higher cellulose (65.37 wt%) content and lower density (634 kg/m3). Crystallinity Index (CI) of CBF was calculated from X-ray diffraction studies and is valued as 50.29%. The surface of CBF was examined using a Scanning Electron Microscope (SEM) for observing the surface morphology. Structural characterization and Chemical functional group were confirmed by Fourier transform infrared spectroscopy (FT-IR). The thermal behavior of CBFs was determined using TG and DTG curves from Thermo gravimetric (TG) analysis. Findings show that the fiber has a semi-elongated nearly circular cross-sectional shape, the fiber diameter is between 180 and 200 μm. TG analysis revealed that these fibers are thermally stable until 210°C. Thus the characterization results confirm the possibility of using CBF for the manufacture of sustainable fiber reinforced polymer composite.

Natural fibers are one of effective substitute for switching artificial fiber and concentrating to reinforce polymer matrixes due to their decomposable character. This study was implied to realize physico-chemical properties of bio fiber obtained from Heteropogon contortus (HC) plant. Heteropogon contortus fibers (HCFs) had cellulose (64.87 wt. %), hemicellulose (19.34 wt. %), lignin (13.56 wt. %), and low density (602 kg/m3). The chemical functional group of HCFs was established by Fourier transform infrared spectroscopy, thermal stability of the fiber up to 220°C discovered by thermogravimetric analysis. Further the assets of HCFs proved that it can act as an excellent reinforcement material as a bio composite. Finally, the tensile properties were carried out through single fiber tensile tests, such as tensile strength, tensile modulus and microfibrillar angle.

This research study was aimed at examining newly identified natural fiber from the bark of Azadirachta indica (AI). The various properties were analyzed and compared with other available bark fibers. The chemical composition of Azadirachta indica fibers (AIFs), high cellulose (68.42 wt.%) content, and low lignin (13.58 wt.%) were discovered. The lower density of 740 kg/m3, and crystallinity index of 65.04% properties were identified. The maximum peak temperature obtained was 321.2 °C in Differential thermogravimetry (DTG) curve. Taken together, all the properties of AIFs indicated that they could be suitable to make green composites for various types of applications.

The increasing environmental awareness has directed attention of the researchers towards the field of natural fiber composites. The aim of this investigation is to understand the physico-chemical properties of fibers extracted from the bark of the Dichrostachys Cinerea (DC) plant. Dichrostachys Cinerea fibers (DCFs) has cellulose (72.4 wt. %), hemicellulose (13.08 wt. %), lignin (16.89 wt. %), density (1240 kg/m3), crystallinity index (57.82%), and tensile strength (873 ± 14 MPa). Besides the cellulose degradation of DCFs at 359.3° vide by the thermo-gravimetric analysis and chemical groups are identified by Fourier transform analysis. Eventually the characterization results of DCFs strongly show the possibility of reinforcement in polymer matrices.

INTRODUCTION: IL6 signaling plays an important role in triggering labor and IL6 is an established biomarker of intrauterine infection/inflammation (IUI) driven preterm labor (PTL). The biology of IL6 during IUI at the maternal-fetal interface was investigated in samples from human subjects and non-human primates (NHP). METHODS: Pregnant women with histologic chorioamnionitis diagnosed by placenta histology were recruited (n=28 term, n=43 for preterm pregnancies from 26-36 completed weeks of gestation). IUI was induced in Rhesus macaque by intraamniotic injection of lipopolysachharide (LPS, n=23). IL1 signaling was blocked using Anakinra (human IL-1 receptor antagonist, n=13), and Tumor necrosis factor (TNF) signaling was blocked by anti TNF-antibody (Adalimumab n=14). The blockers were given before LPS. All animals including controls (intraamniotic injection of saline n=27), were delivered 16h after LPS/saline exposure at about 80% gestation. RESULTS: IUI induced a robust expression of IL6 mRNAs in the fetal membranes (chorion-amnion-decidua tissue) both in humans (term and preterm) and NHP. The major sources of IL6 mRNA expression were the amnion mesenchymal cells (AMC) and decidua stroma cells. Additionally, during IUI in the NHP, ADAM17 (a protease that cleaves membrane bound IL6 receptor (IL6R) to release a soluble form) and IL6R mRNA increased in the fetal membranes, and the ratio of IL6 and soluble forms of IL6R, gp130 increased in the amniotic fluid signifying upregulation of IL6 trans-signaling. Both IL1 and TNF blockade suppressed LPS-induced IL6 mRNAs in the AMC and variably decreased elements of IL6 trans-signaling. DISCUSSION: These data suggest that IL1 and TNF blockers may be useful anti-inflammatory agents via suppression of IL6 signaling at the maternal-fetal interface.

The study of polymer matrix composites had become an important topic for academic and industrial research. The current thrust for materials which are environmental friendly and biodegradable made researchers to focus on alternate options to synthetic materials. One major area of research in this direction is in the area composites of polymers with natural fibers. These composites exhibit moderate to good mechanical properties. This overview briefs about the use of polymers for different natural fiber composites. This review is expected to provide a general overview for the materials selection for the design of composite materials with improved properties.

Intrauterine infection/inflammation (IUI) is a frequent complication of pregnancy leading to preterm labor and fetal inflammation. How inflammation is modulated at the maternal-fetal interface is unresolved. We compared transcriptomics of amnion (a fetal tissue in contact with amniotic fluid) in a preterm Rhesus macaque model of IUI induced by lipopolysaccharide with human cohorts of chorioamnionitis. Bulk RNA sequencing (RNA-seq) amnion transcriptomic profiles were remarkably similar in both Rhesus and human subjects and revealed that induction of key labor-mediating genes such as IL1 and IL6 was dependent on nuclear factor κB (NF-κB) signaling and reversed by the anti-tumor necrosis factor (TNF) antibody Adalimumab. Inhibition of collagen biosynthesis by IUI was partially restored by Adalimumab. Interestingly, single-cell transcriptomics, flow cytometry, and immunohistology demonstrated that a subset of amnion mesenchymal cells (AMCs) increase CD14 and other myeloid cell markers during IUI both in the human and Rhesus macaque. Our data suggest that CD14+ AMCs represent activated AMCs at the maternal-fetal interface.

Up to 40% of preterm births are associated with histological chorioamnionitis (HCA), which leads to elevated levels of pro-inflammatory mediators and microbial products in the amniotic fluid, which come in contact with fetal lungs. Yet, fetal pulmonary immune responses to such exposure remain poorly characterized. To address this gap, we used our established HCA model, in which pregnant Rhesus macaques receive intraamniotic (IA) saline or LPS. IA LPS induced a potent and rapid myeloid cell response in fetal lungs, dominated by neutrophils and monocytes/macrophages. Infiltrating and resident myeloid cells exhibited transcriptional profiles consistent with exposure to TLR ligands, as well as cytokines, notably IL-1 and TNFα. Although simultaneous, in vivo blockade of IL-1 and TNFα signaling did not prevent the inflammatory cell recruitment, it blunted the lung overall inflammatory state reducing communication between, and activation of, infiltrating immune cells. Our data indicate that the fetal innate immune system can mount a rapid multi-faceted pulmonary immune response to in utero exposure to inflammation. These data provide mechanistic insights into the association between HCA and the postnatal lung morbidities of the premature infant and highlight therapeutic potential of inflammatory blockade in the fetus.

Intrauterine infection/inflammation (IUI) is a major contributor to preterm labor (PTL). However, IUI does not invariably cause PTL. We hypothesized that quantitative and qualitative differences in immune response exist in subjects with or without PTL. To define the triggers for PTL, we developed rhesus macaque models of IUI driven by lipopolysaccharide (LPS) or live Escherichia coli. PTL did not occur in LPS challenged rhesus macaques, while E. coli-infected animals frequently delivered preterm. Although LPS and live E. coli both caused immune cell infiltration, E. coli-infected animals showed higher levels of inflammatory mediators, particularly interleukin 6 (IL-6) and prostaglandins, in the chorioamnion-decidua and amniotic fluid (AF). Neutrophil infiltration in the chorio-decidua was a common feature to both LPS and E. coli. However, neutrophilic infiltration and IL6 and PTGS2 expression in the amnion was specifically induced by live E. coli. RNA sequencing (RNA-seq) analysis of fetal membranes revealed that specific pathways involved in augmentation of inflammation including type I interferon (IFN) response, chemotaxis, sumoylation, and iron homeostasis were up-regulated in the E. coli group compared to the LPS group. Our data suggest that the intensity of the host immune response to IUI may determine susceptibility to PTL.

Accumulation of activated neutrophils at the feto-maternal interface is a defining hallmark of intrauterine inflammation (IUI) that might trigger an excessive immune response during pregnancy. Mechanisms responsible of this massive neutrophil recruitment are poorly investigated. We have previously showed that intraamniotic injection of LPS in rhesus macaques induced a neutrophil predominant inflammatory response similar to that seen in human IUI. Here, we demonstrate that anti-TNF antibody (Adalimumab) inhibited ~80% of genes induced by LPS involved in inflammatory signaling and innate immunity in chorio-decidua neutrophils. Consistent with the gene expression data, TNF-blockade decreased LPS-induced neutrophil accumulation and activation at the feto-maternal interface. We also observed a reduction in IL-6 and other pro-inflammatory cytokines but not prostaglandins concentrations in the amniotic fluid. Moreover, TNF-blockade decreased mRNA expression of inflammatory cytokines in the chorio-decidua but not in the uterus, suggesting that inhibition of TNF-signaling decreased the inflammation in a tissue-specific manner within the uterine compartment. Taken together, our results demonstrate a predominant role for TNF-signaling in modulating the neutrophilic infiltration at the feto-maternal interface during IUI and suggest that blockade of TNF-signaling could be considered as a therapeutic approach for IUI, the major leading cause of preterm birth.

Zika virus (ZIKV) infection of pregnant women can cause fetal microcephaly and other neurologic defects. We describe the development of a non-human primate model to better understand fetal pathogenesis. To reliably induce fetal infection at defined times, four pregnant rhesus macaques are inoculated intravenously and intraamniotically with ZIKV at gestational day (GD) 41, 50, 64, or 90, corresponding to first and second trimester of gestation. The GD41-inoculated animal, experiencing fetal death 7 days later, has high virus levels in fetal and placental tissues, implicating ZIKV as cause of death. The other three fetuses are carried to near term and euthanized; while none display gross microcephaly, all show ZIKV RNA in many tissues, especially in the brain, which exhibits calcifications and reduced neural precursor cells. Given that this model consistently recapitulates neurologic defects of human congenital Zika syndrome, it is highly relevant to unravel determinants of fetal neuropathogenesis and to explore interventions.

Neutrophil infiltration of the chorioamnion-decidua tissue at the maternal-fetal interface (chorioamnionitis) is a leading cause of prematurity, fetal inflammation, and perinatal mortality. We induced chorioamnionitis in preterm rhesus macaques by intraamniotic injection of LPS. Here, we show that, during chorioamnionitis, the amnion upregulated phospho-IRAK1-expressed neutrophil chemoattractants CXCL8 and CSF3 in an IL-1-dependent manner. IL-1R blockade decreased chorio-decidua neutrophil accumulation, neutrophil activation, and IL-6 and prostaglandin E2 concentrations in the amniotic fluid. Neutrophils accumulating in the chorio-decidua had increased survival mediated by BCL2A1, and IL-1R blockade also decreased BCL2A1+ chorio-decidua neutrophils. Readouts for inflammation in a cohort of women with preterm delivery and chorioamnionitis were similar to findings in the rhesus macaques. IL-1 is a potential therapeutic target for chorioamnionitis and associated morbidities.