Trop2: from development to disease

BACKGROUND

Trop2 was first discovered as a biomarker of invasive trophoblast cells. Since then most research has focused on its role in tumourigenesis because it is highly expressed in the vast majority of human tumours and animal models of cancer. It is also highly expressed in stem cells and in many organs during development.

RESULTS

We review the multifaceted role of Trop2 during development and tumourigenesis, including its role in regulating cell proliferation and migration, self-renewal, and maintenance of basement membrane integrity. We discuss the evolution of Trop2 and its related protein Epcam (Trop1), including their distinct roles. Mutation of Trop2 leads to gelatinous drop-like corneal dystrophy, whereas over-expression of Trop2 in human tumours promotes tumour aggressiveness and increases mortality. Although Trop2 expression is sufficient to promote tumour growth, the surprising discovery that Trop2-null mice have an increased risk of tumour development has highlighted the complexity of Trop2 signaling. Recently, studies have begun to identify the mechanisms underlying TROP2’s functions, including regulated intramembrane proteolysis or specific interactions with integrin b1 and claudin proteins.

CONCLUSIONS

Understanding the mechanisms underlying TROP2 signaling will clarify its role during development, aid in the development of better cancer treatments and unlock a promising new direction in regenerative medicine.

Glucocorticoid regulation of lung development: lessons learned from conditional GR knockout mice

Glucocorticoid (GC) steroid hormones have well-characterized roles in the regulation of systemic homeostasis, yet less understood is their known role in utero to mature the developing respiratory system in preparation for birth. During late gestation, endogenously produced GCs thin the interstitial tissue of the lung, causing the vasculature and future airspaces to come into close alignment, allowing for efficient gas exchange at birth. More potent synthetic GCs are also used worldwide to reduce the severity of respiratory distress suffered by preterm infants; however, their clinical benefits are somewhat offset by potential detrimental long-term effects on health and development. Here, we review the recent literature studying both global and conditional gene-targeted respiratory mouse models of either GC deficiency or glucocorticoid receptor ablation. Although some discrepancies exist between these transgenic mouse strains, these models have revealed specific roles for GCs in particular tissue compartments of the developing lung and identify the mesenchyme as the critical site for glucocorticoid receptor-mediated lung maturation, particularly for the inhibition of cell proliferation and epithelial cell differentiation. Specific mesenchymal and epithelial cell-expressed gene targets that may potentially mediate the effect of GCs have also been identified in these studies and imply a GC-regulated system of cross talk between compartments during lung development. A better understanding of the specific roles of GCs in specific cell types and compartments of the fetal lung will allow the development of a new generation of selective GC ligands, enabling better therapeutic treatments with fewer side effects for lung immaturity at birth in preterm infants.

Mesenchymal glucocorticoid receptor regulates the development of multiple cell layers of the mouse lung

Endogenous glucocorticoid (GC) hormones, signaling via the GC receptor (GR), are essential for normal lung development, and synthetic GCs are routinely used to treat respiratory disorders of very preterm babies. Germline GR knockout (GR(-/-)) mice show immature lung morphology and severe lung cellular hyperplasia during embryogenesis and die at birth due to respiratory failure. Two recent studies have reported contradictory results regarding the necessity for GR expression in specific lung germ layers during respiratory maturation. We further investigate in detail the lung phenotype in mice with a conditional deletion of GR in the endothelium, mesenchyme, and lung epithelium. We show that loss of GR in the mesenchyme alone produces a retarded lung phenotype almost identical to that of germline GR(-/-) mice, including severe postnatal lethality and lung cell hyperplasia. Loss of GR in lung epithelial cells and the endothelium had no gross effect on survival or lung morphology, but loss of epithelial GR caused increased cell proliferation in multiple compartments. Mesenchymal GR loss also produced increased epithelial cell proliferation, implying the existence of GC-regulated germ layer cross-talk. Protein levels of GR-mediated cell cycle regulators, including the cyclin-dependent kinase inhibitor p21(CIP1) and the growth factor midkine, were unaffected by mesenchymal GR deletion, yet expression of the extracellular matrix proteoglycan versican was up-regulated in the distal lung on loss of mesenchymal GR. These results show that GR-mediated signaling from the mesenchyme regulates respiratory maturation and ultimately survival at birth and that a key GR-repressed transcriptional target in lung mesenchymal cells is versican.

Human Amnion Epithelial Cells Modulate Ventilation-Induced White Matter Pathology in Preterm Lambs

BACKGROUND

Preterm infants can be inadvertently exposed to high tidal volumes (VT) during resuscitation in the delivery room due to limitations of available equipment. High VT ventilation of preterm lambs produces cerebral white matter (WM) pathology similar to that observed in preterm infants who develop cerebral palsy. We hypothesized that human amnion epithelial cells (hAECs), which have anti-inflammatory and regenerative properties, would reduce ventilation-induced WM pathology in neonatal late preterm lamb brains.

METHODS

Two groups of lambs (0.85 gestation) were used, as follows: (1) ventilated lambs (Vent; n = 8) were ventilated using a protocol that induces injury (VT targeting 15 ml/kg for 15 min, with no positive end-expiratory pressure) and were then maintained for another 105 min, and (2) ventilated + hAECs lambs (Vent+hAECs; n = 7) were similarly ventilated but received intravenous and intratracheal administration of 9 × 10(7) hAECs (18 × 10(7) hAECs total) at birth. Oxygenation and ventilation parameters were monitored in real time; cerebral oxygenation was measured using near-infrared spectroscopy. qPCR (quantitative real-time PCR) and immunohistochemistry were used to assess inflammation, vascular leakage and astrogliosis in both the periventricular and subcortical WM of the frontal and parietal lobes. An unventilated control group (UVC; n = 5) was also used for qPCR analysis of gene expression. Two-way repeated measures ANOVA was used to compare physiological data. Student's t test and one-way ANOVA were used for immunohistological and qPCR data comparisons, respectively.

RESULTS

Respiratory parameters were not different between groups. Interleukin (IL)-6 mRNA levels in subcortical WM were lower in the Vent+hAECs group than the Vent group (p = 0.028). IL-1β and IL-6 mRNA levels in periventricular WM were higher in the Vent+hAECs group than the Vent group (p = 0.007 and p = 0.001, respectively). The density of Iba-1-positive microglia was lower in the subcortical WM of the parietal lobes (p = 0.010) in the Vent+hAECs group but not in the periventricular WM. The number of vessels in the WM of the parietal lobe exhibiting protein extravasation was lower (p = 0.046) in the Vent+hAECs group. Claudin-1 mRNA levels were higher in the periventricular WM (p = 0.005). The density of GFAP-positive astrocytes was not different between groups.

CONCLUSIONS

Administration of hAECs at the time of birth alters the effects of injurious ventilation on the preterm neonatal brain. Further studies are required to understand the regional differences in the effects of hAECs on ventilation-induced WM pathology and their net effect on the developing brain.

Single Sustained Inflation followed by Ventilation Leads to Rapid Cardiorespiratory Recovery but Causes Cerebral Vascular Leakage in Asphyxiated Near-Term Lambs

Background

A sustained inflation (SI) rapidly restores cardiac function in asphyxic, bradycardic newborns but its effects on cerebral haemodynamics and brain injury are unknown. We determined the effect of different SI strategies on carotid blood flow (CaBF) and cerebral vascular integrity in asphyxiated near-term lambs.

Methods

Lambs were instrumented and delivered at 139 ± 2 d gestation and asphyxia was induced by delaying ventilation onset. Lambs were randomised to receive 5 consecutive 3 s SI (multiple SI; n = 6), a single 30 s SI (single SI; n = 6) or conventional ventilation (no SI; n = 6). Ventilation continued for 30 min in all lambs while CaBF and respiratory function parameters were recorded. Brains were assessed for gross histopathology and vascular leakage.

Results

CaBF increased more rapidly and to a greater extent during a single SI (p = 0.01), which then decreased below both other groups by 10 min, due to a higher cerebral oxygen delivery (p = 0.01). Blood brain barrier disruption was increased in single SI lambs as indicated by increased numbers of blood vessel profiles with plasma protein extravasation (p = 0.001) in the cerebral cortex. There were no differences in CaBF or cerebral oxygen delivery between the multiple SI and no SI lambs.

Conclusions

Ventilation with an initial single 30 s SI improves circulatory recovery, but is associated with greater disruption of blood brain barrier function, which may exacerbate brain injury suffered by asphyxiated newborns. This injury may occur as a direct result of the initial SI or to the higher tidal volumes delivered during subsequent ventilation.

The oncogene Trop2 regulates fetal lung cell proliferation

The factors regulating growth of the developing lung are poorly understood, although the degree of fetal lung expansion is critical. The oncogene Trop2 (trophoblast antigen 2) is upregulated during accelerated fetal lung growth, and we hypothesized that it may regulate normal fetal lung growth. We investigated Trop2 expression in the fetal and neonatal sheep lung during accelerated and delayed lung growth induced by alterations in fetal lung expansion, as well as in response to glucocorticoids. Trop2 expression was measured using real-time PCR and localized spatially using in situ hybridization and immunofluorescence. During normal lung development, Trop2 expression was higher at 90 days gestational age (GA; 4.0 ± 0.8) than at 128 days GA (1.0 ± 0.1), decreased to 0.5 ± 0.1 at 142 days GA (full term ∼147 days GA), and was positively correlated to lung cell proliferation rates (r = 0.953, P < 0.005). Trop2 expression was regulated by fetal lung expansion, but not by glucocorticoids. It was increased nearly threefold by 36 h of increased fetal lung expansion (P < 0.05) and was reduced to ∼55% of control levels by reduced fetal lung expansion (P < 0.05). Trop2 expression was associated with lung cell proliferation during normal and altered lung growth, and the TROP2 protein colocalized with Ki-67-positive cells in the fetal lung. TROP2 was predominantly localized to fibroblasts and type II alveolar epithelial cells. Trop2 small interfering RNA decreased Trop2 expression by ∼75% in cultured fetal rat lung fibroblasts and decreased their proliferation by ∼50%. Cell viability was not affected. This study demonstrates that TROP2 regulates lung cell proliferation during development.

Intrauterine Growth Restriction Alters the Postnatal Development of the Rat Cerebellum

Intrauterine growth restriction (IUGR) is a major cause of antenatal brain injury. We aimed to characterize cerebellar deficits following IUGR and to investigate the potential underlying cellular and molecular mechanisms. At embryonic day 18, pregnant rats underwent either sham surgery (controls; n = 23) or bilateral uterine vessel ligation to restrict blood flow to fetuses (IUGR; n = 20). Offspring were collected at postnatal day 2 (P2), P7, and P35. Body weights were reduced at P2, P7, and P35 in IUGR offspring (p < 0.05) compared with controls. At P7, the width of the external granule layer (EGL) was 30% greater in IUGR than control rats (p < 0.05); there was no difference in the width of the proliferative zone or in the density of Ki67-positive cells in the EGL. Bergmann glia were disorganized at P7 and P35 in IUGR pups, and by P35, there was a 10% decrease in Bergmann glial fiber density (p < 0.05) compared with controls. At P7, trophoblast antigen-2 (Trop2) mRNA and protein levels in the cerebellum were decreased by 88 and 40%, respectively, and astrotactin 1 mRNA levels were increased by 20% in the IUGR rats (p < 0.05) compared with controls; there was no difference in ASTN1 protein. The expressions of other factors known to regulate cerebellar development (astrotactin 2, brain-derived neurotrophic factor, erb-b2 receptor tyrosine kinase 4, neuregulin 1, sonic hedgehog and somatostatin) were not different between IUGR and control rats at P7 or P35. These data suggest that damage to the migratory scaffold (Bergmann glial fibers) and alterations in the genes that influence migration (Trop2 and Astn1) may underlie the deficits in postnatal cerebellar development following IUGR.

Differential short-term regional effects of early high dose erythropoietin on white matter in preterm lambs after mechanical ventilation

Inadvertently injurious ventilation of preterm neonates in the delivery room can cause cerebral white matter (WM) inflammation and injury. We investigated the impact of an early high dose of recombinant human erythropoietin (EPO) on ventilation-induced WM changes in preterm lambs. Injurious ventilation, targeting a V(T) of 15 ml kg(-1) with no positive end-expiratory pressure, was initiated for 15 min in preterm lambs (0.85 gestation). Conventional ventilation was continued for a further 105 min. Lambs received either 5000 IU kg(-1) of EPO (EPREX®; Vent+EPO; n = 6) or vehicle (Vent; n = 8) via an umbilical vein at 4 ± 2 min. Markers of WM injury and inflammation were assessed using quantitative real-time PCR (qPCR) and immunohistochemistry and compared to a group of unventilated controls (UVC; n = 4). In Vent+EPO lambs compared to Vent lambs: (i) interleukin (IL)-1β and IL-6 mRNA levels in the periventricular WM and IL-8 mRNA levels in the subcortical WM were higher (P < 0.05 for all); (ii) the density of microglia within the aggregations was not different in the periventricular WM and was lower in the subcortical WM (P = 0.001); (iii) the density of astrocytes was lower in the subcortical WM (P = 0.002); (iv) occludin and claudin-1 mRNA levels were higher in the periventricular WM (P < 0.02 for all) and (vi) the number of blood vessels with protein extravasation was lower (P < 0.05). Recombinant human EPO had variable regional effects within the WM when administered during injurious ventilation. The adverse short-term outcomes discourage the use of early high dose EPO administration in preterm ventilated babies.

Trop2 regulates motility and lamellipodia formation in cultured fetal lung fibroblasts

Proliferation and migration of fibroblasts are vital for fetal lung development. However, the regulatory mechanisms are poorly understood. We have previously shown that TROP2 gene expression is closely associated with fetal lung cell proliferation in vivo and that TROP2 knockdown decreases proliferation of fetal lung fibroblasts in culture. We hypothesized that the Trop2 protein also regulates the morphology and motility of fetal lung fibroblasts. Fibroblasts isolated from fetal rat lungs (gestational age embryonic day 19) adopted a myofibroblast-like morphology in culture. Trop2 protein was localized to lamellipodia. TROP2 siRNA significantly decreased: TROP2 mRNA levels by 77%, the proportion of cells containing Trop2 protein by 70%, and cell proliferation by 50%. TROP2 siRNA also decreased the degree of motility as determined by the number of gridlines that cells moved across (2.2 ± 0.2 vs. 3.2 ± 0.2; P < 0.001). TROP2 knockdown altered cell morphology, causing a notable absence of lamellipodia and abnormal localization of components of the cell migration apparatus, and it reduced phosphorylated ERK1 and ERK2 levels. In contrast, TROP2 overexpression significantly increased: TROP2 mRNA levels by 40-fold, cell proliferation by 40%, the proportion of cells that were motile by 20%, and the number of gridlines that cells moved across (2.1 ± 0.2 vs. 1.6 ± 0.1; P < 0.001). Our data suggest that Trop2 regulates cell proliferation and motility and that it does so by regulating the ERK pathway and several critical components of the cell migration apparatus.

Erythropoietin Protects Against Lipopolysaccharide-Induced Microgliosis and Abnormal Granule Cell Development in the Ovine Fetal Cerebellum

Erythropoietin (EPO) ameliorates inflammation-induced injury in cerebral white matter (WM). However, effects of inflammation on the cerebellum and neuroprotective effects of EPO are unknown. Our aims were to determine: (i) whether lipopolysaccharide (LPS)-induced intrauterine inflammation causes injury to, and/or impairs development of the cerebellum; and (ii) whether recombinant human EPO (rhEPO) mitigates these changes. At 107 ± 1 days gestational age (DGA; ~0.7 of term), fetal sheep received LPS (~0.9 μg/kg; i.v.) or an equivalent volume of saline, followed 1 h later with 5000 IU/kg rhEPO (i.v.) or an equivalent volume of saline (i.v.). This generated the following experimental groups: control (saline + saline; n = 6), LPS (LPS + saline, n = 8) and LPS + rhEPO (n = 8). At necropsy (116 ± 1 DGA; ~0.8 of term) the brain was perfusion-fixed and stained histologically (H&E) and immunostained to identify granule cells (Neuronal Nuclei, NeuN), granule cell proliferation (Ki67), Bergmann glia (glial fibrillary acidic protein, GFAP), astrogliosis (GFAP) and microgliosis (Iba-1). In comparison to controls, LPS fetuses had an increased density of Iba-1-positive microglia (p < 0.005) in the lobular WM; rhEPO prevented this increase (p < 0.05). The thickness of both the proliferative (Ki67-positive) and post-mitotic zones (Ki67-negative) of the EGL were increased in LPS-exposed fetuses compared to controls (p < 0.05), but were not different between controls and LPS + rhEPO fetuses. LPS also increased (p < 0.001) the density of granule cells (NeuN-positive) in the internal granule layer (IGL); rhEPO prevented the increase (p < 0.01). There was no difference between groups in the areas of the vermis (total cross-section), molecular layer (ML), IGL or WM, the density of NeuN-positive granule cells in the ML, the linear density of Bergmann glial fibers, the areal density or somal area of the Purkinje cells, the areal coverage of GFAP-positive astrocytes in the lobular and deep WM, the density of Iba-1-positive microglia in the deep WM or the density of apopotic cells in the cerebellum. LPS-induced intrauterine inflammation caused microgliosis and abnormal development of granule cells. rhEPO ameliorated these changes, suggesting that it is neuroprotective against LPS-induced inflammatory effects in the cerebellum.

cAMP response element binding protein1 is essential for activation of steroyl co-enzyme a desaturase 1 (Scd1) in mouse lung type II epithelial cells

Cyclic AMP Response Element-Binding Protein 1 (Creb1) is a transcription factor that mediates cyclic adenosine 3′, 5′-monophosphate (cAMP) signalling in many tissues. Creb1^−/− mice die at birth due to respiratory failure and previous genome-wide microarray analysis of E17.5 Creb1^−/− fetal mouse lung identified important Creb1-regulated gene targets during lung development. The lipogenic enzymes stearoyl-CoA desaturase 1 (Scd1) and fatty acid synthase (Fasn) showed highly reduced gene expression in Creb1^−/− lungs. We therefore hypothesized that Creb1 plays a crucial role in the transcriptional regulation of genes involved in pulmonary lipid biosynthetic pathways during lung development. In this study we confirmed that Scd1 and Fasn mRNA levels were down regulated in the E17.5 Creb1^−/− mouse lung while the lipogenic-associated transcription factors SrebpF1, C/ebpα and Pparγ were increased. In vivo studies using germline (Creb1^−/−) and lung epithelial-specific (Creb1^EpiΔ/Δ) Creb1 knockout mice showed strongly reduced Scd1, but not Fasn gene expression and protein levels in lung epithelial cells. In vitro studies using mouse MLE-15 epithelial cells showed that forskolin-mediated activation of Creb1 increased both Scd1 gene expression and protein synthesis. Additionally, MLE15 cells transfected with a dominant-negative ACreb vector blocked forskolin-mediated stimulation of Scd1 gene expression. Lipid profiling in MLE15 cells showed that dominant-negative ACreb suppressed forskolin-induced desaturation of ether linked lipids to produce plasmalogens, as well as levels of phosphatidylethanolamine, ceramide and lysophosphatidylcholine. Taken together these results demonstrate that Creb1 is essential for the induction and maintenance of Scd1 in developing fetal mouse lung epithelial cells.

Identification of Betamethasone-Regulated Target Genes and Cell Pathways in Fetal Rat Lung Mesenchymal Fibroblasts

Preterm birth is characterized by severe lung immaturity that is frequently treated antenatally or postnatally with the synthetic steroid betamethasone. The underlying cellular targets and pathways stimulated by betamethasone in the fetal lung are poorly defined. In this study, betamethasone was compared with corticosterone in steroid-treated primary cultures of fetal rat lung fibroblasts stimulated for 6 hours and analyzed by whole-cell transcriptome sequencing and glucocorticoid (GC) receptor (GR) chromatin immunoprecipitation sequencing (ChIP-Seq) analysis. Strikingly, betamethasone stimulated a much stronger transcriptional response compared with corticosterone for both induced and repressed genes. A total of 483 genes were significantly stimulated by betamethasone or corticosterone, with 476 stimulated by both steroids, indicating a strong overlap in regulation. Changes in mRNA levels were confirmed by quantitative PCR for eight induced and repressed target genes. Pathway analysis identified cell proliferation and cytoskeletal/cell matrix remodeling pathways as key processes regulated by both steroids. One target, transglutaminase 2 (Tgm2), was localized to fetal lung mesenchymal cells. Tgm2 mRNA and protein levels were strongly increased in fibroblasts by both steroids. Whole-genome GR ChIP-Seq analysis with betamethasone identified GC response element-binding sites close to the previously characterized GR target genes Per1, Dusp1, Fkbp5, and Sgk1 and near the genes identified by transcriptome sequencing encoding Crispld2, Tgm2, Hif3α, and Kdr, defining direct genomic induction of expression in fetal lung fibroblasts via the GR. These results demonstrate that betamethasone stimulates specific genes and cellular pathways controlling cell proliferation and extracellular matrix remodeling in lung mesenchymal fibroblasts, providing a basis for betamethasone's treatment efficacy in preterm birth.

Glucocorticoids influence versican and chondroitin sulphate proteoglycan levels in the fetal sheep lung

BACKGROUND

Prenatal glucocorticoid treatment decreases alveolar tissue volumes and facilitates fetal lung maturation, however the mechanisms responsible are largely unknown. This study examines whether changes in versican levels or sulphation patterns of chondroitin sulphate (CS) side chains, are associated with glucocorticoid-induced reductions in peri-alveolar tissue volumes.

METHODS

Lung tissue was collected from 1) fetal sheep at 131 ± 0.1 days gestational age (GA) infused with cortisol (122-131d GA) to prematurely induce a pre-parturient-like rise in circulating cortisol, 2) fetal sheep at 143d GA bilaterally adrenalectomised (ADX) at 112d GA to remove endogenous cortisol and 3) fetal sheep at 124d GA in which bolus doses (2 × 11.4 mg) of betamethasone were administered to the pregnant ewe. The level and distribution of versican and CS glycosaminoglycans (GAG) were determined using immunohistochemistry (IHC). Fluorophore assisted carbohydrate electrophoresis (FACE) was used to determine changes in CS sulphation patterns.

RESULTS

Cortisol infusion significantly decreased chondrotin-6-sulphate levels (C-6-S) to 16.4 ± 0.7 AU, compared with saline-infused fetuses (18.9 ± 0.7 AU: p = 0.04) but did not significantly alter the level of versican or chondroitin-4-sulphate (C-4-S). ADX significantly increased the level of C-4-S (28.2 ± 2.2 AU), compared with sham-operated fetuses (17.8 ± 2.0 AU; p = 0.006) without altering versican or C-6-S levels. Betamethasone significantly decreased versican, C-4-S and C-6-S in the fetal sheep lung (19.2 ± 0.9 AU, 24.9 ± 1.4 AU and 23.2 ± 1.0 AU, respectively), compared with saline-exposed fetuses (24.3 ± 0.4 AU, p = 0.0004; 33.3±0.6 AU, p = 0.0003; 29.8±1.3 AU, 0.03, respectively).

CONCLUSIONS

These results indicate that glucocorticoids alter versican levels and CS side chain microstructure in alveolar lung tissue. Betamethasone appears to have a greater impact on versican and CS side chains than cortisol.

Innovations in the prevention and treatment of postpartum hemorrhage: Analysis of a novel medicines development pipeline database

Background

A significant barrier to improving prevention and treatment of postpartum hemorrhage (PPH) is a lack of innovative medicines that meet the needs of women and providers, particularly those in low‐and middle‐income countries (LMICs). The Accelerating Innovation for Mothers (AIM) project established a new database of candidate medicines under development for five pregnancy‐related conditions between 2000 and 2021.

Objective

To systematically identify and rank candidates for prevention and treatment of PPH.

Search Strategy

Adis Insight, Pharmaprojects, WHO ICTRP, PubMed, and grant databases were searched to develop the AIM database.

Selection Criteria

AIM database was searched for candidates being evaluated for PPH prevention and treatment, regardless of phase.

Data Collection and Analysis

Candidates were ranked as high, medium, or low potential based on prespecified criteria. Analysis was primarily descriptive, describing candidates and development potential.

Main Results

Of the 444 unique candidates, only 39 pertained to PPH. One was high potential (heat‐stable/inhaled oxytocin) and three were medium potential (melatonin, vasopressin and dofetilide via nanoparticle delivery).

Conclusion

The pipeline for new PPH medicines is concerningly limited, lacking diversity, and showing little evidence of novel technologies. Without significant investment in early‐phase research, it is unlikely that new products will emerge.

A new database of maternal medicine development shows few new PPH candidates are in the pipeline. Significant investment is needed, particularly in early‐phase research.

Analysis of a maternal health medicines pipeline database 2000-2021: New candidates for the prevention and treatment of fetal growth restriction

OBJECTIVE

The Accelerating Innovation for Mothers project established a new database of candidate medicines under development between 2000 and 2021 for five pregnancy-related conditions, including fetal growth restriction. The objective was to assess medicines for fetal growth restriction and their potential for clinical use globally.

DESIGN

Landscape analysis.

SETTING

Global (focus on low- and middle-income countries, LMICs).

SAMPLE

Drugs, dietary supplements and biologics under investigation for prevention or treatment of fetal growth restriction.

METHODS

A research pipeline database of medicines was created through searching AdisInsight, PubMed and various grant and clinical trial databases. Analysis of clinical and preclinical candidates were descriptive.

MAIN OUTCOMES MEASURES

Fetal growth restriction candidates in clinical development were identified and ranked as high, medium or low potential based on prespecified criteria, including efficacy, safety and accessibility.

RESULTS

Of the 444 unique candidates in the database across all five pregnancy-related conditions, 63 were for fetal growth restriction. Of these, 31 were in clinical development (phases I, II or III) and 32 were in preclinical development. Three candidates, aspirin, l-arginine and vitamin D, were ranked as having high potential as preventive agents. There were no high-potential candidates for treating fetal growth restriction, although five candidates were ranked as having medium potential: allylestrenol, dalteparin, omega-3 fatty acids, tadalafil, and United Nations International Multiple Micronutrient Antenatal Preparation (UNIMMAP).

CONCLUSIONS

l-Arginine, aspirin and vitamin D are promising, high-potential preventative agents for fetal growth restriction. Based on the medicines pipeline, new pharmacological agents for fetal growth restriction are unlikely to emerge in the near future.

Glucocorticoid signalling drives reduced versican levels in the fetal mouse lung

Glucocorticoid (GC) signaling via the glucocorticoid receptor (GR) is essential for lung maturation in mammals. Previous studies using global or conditional mouse model knockouts of the GR gene have established that GR-mediated signaling in the interstitial mesenchyme of the fetal lung is critical for normal lung development. Screens for downstream GC-targets in conditional mesenchymal GR deficient mouse lung (GRmesKO) identified Versican (Vcan), an important extracellular matrix component and cell proliferation regulator, as a potential GR-regulated target. We show that, of the five major VCAN isoforms, the VCAN-V1 isoform containing the GAGβ domain is the predominant VCAN isoform in the fetal mouse lung distal mesenchyme at both E16.5 and E18.5, whereas the GAGα-specific VCAN-V2 isoform was only localized to the smooth muscle surrounding proximal airways. Both Vcan-V1 mRNA and protein levels were strongly overexpressed in the GRmesKO lung at E18.5. Finally, we investigated the GC regulation of the ECM protease ADAMTS 12 and showed that Adamts 12 mRNA levels were markedly reduced at E18.5 in GRmesKO fetal mouse lung and were strongly induced by both cortisol and betamethasone in cultures of primary rat fetal lung fibroblasts. ADAMTS12 protein immunoreactivity was also strongly increased in the distal lung at E18.5, after dexamethasone treatment in utero. In summary, glucocorticoid signaling via GR represses GAGβ domain-containing VCAN isoforms in distal lung mesenchyme in vivo by repressing Vcan gene expression and, in part, by inducing the ECM protease ADAMTS12, thereby contributing to the control of ECM remodelling and lung cell proliferation prior to birth.

Factors influencing the participation of pregnant and lactating women in clinical trials: A mixed-methods systematic review

BACKGROUND

Poor representation of pregnant and lactating women and people in clinical trials has marginalised their health concerns and denied the maternal-fetal/infant dyad benefits of innovation in therapeutic research and development. This mixed-methods systematic review synthesised factors affecting the participation of pregnant and lactating women in clinical trials, across all levels of the research ecosystem.

METHODS AND FINDINGS

We searched 8 databases from inception to 14 February 2024 to identify qualitative, quantitative, and mixed-methods studies that described factors affecting participation of pregnant and lactating women in vaccine and therapeutic clinical trials in any setting. We used thematic synthesis to analyse the qualitative literature and assessed confidence in each qualitative review finding using the GRADE-CERQual approach. We compared quantitative data against the thematic synthesis findings to assess areas of convergence or divergence. We mapped review findings to the Theoretical Domains Framework (TDF) and Capability, Opportunity, and Motivation Model of Behaviour (COM-B) to inform future development of behaviour change strategies. We included 60 papers from 27 countries. We grouped 24 review findings under 5 overarching themes: (a) interplay between perceived risks and benefits of participation in women's decision-making; (b) engagement between women and the medical and research ecosystems; (c) gender norms and decision-making autonomy; (d) factors affecting clinical trial recruitment; and (e) upstream factors in the research ecosystem. Women's willingness to participate in trials was affected by: perceived risk of the health condition weighed against an intervention's risks and benefits, therapeutic optimism, intervention acceptability, expectations of receiving higher quality care in a trial, altruistic motivations, intimate relationship dynamics, and power and trust in medicine and research. Health workers supported women's participation in trials when they perceived clinical equipoise, had hope for novel therapeutic applications, and were convinced an intervention was safe. For research staff, developing reciprocal relationships with health workers, having access to resources for trial implementation, ensuring the trial was visible to potential participants and health workers, implementing a woman-centred approach when communicating with potential participants, and emotional orientations towards the trial were factors perceived to affect recruitment. For study investigators and ethics committees, the complexities and subjectivities in risk assessments and trial design, and limited funding of such trials contributed to their reluctance in leading and approving such trials. All included studies focused on factors affecting participation of cisgender pregnant women in clinical trials; future research should consider other pregnancy-capable populations, including transgender and nonbinary people.

CONCLUSIONS

This systematic review highlights diverse factors across multiple levels and stakeholders affecting the participation of pregnant and lactating women in clinical trials. By linking identified factors to frameworks of behaviour change, we have developed theoretically informed strategies that can help optimise pregnant and lactating women's engagement, participation, and trust in such trials.

New medicines for spontaneous preterm birth prevention and preterm labour management: landscape analysis of the medicine development pipeline

BACKGROUND

There are few medicines in clinical use for managing preterm labor or preventing spontaneous preterm birth from occurring. We previously developed two target product profiles (TPPs) for medicines to prevent spontaneous preterm birth and manage preterm labor. The objectives of this study were to 1) analyse the research and development pipeline of medicines for preterm birth and 2) compare these medicines to target product profiles for spontaneous preterm birth to identify the most promising candidates.

METHODS

Adis Insight, Pharmaprojects, WHO international clinical trials registry platform (ICTRP), PubMed and grant databases were searched to identify candidate medicines (including drugs, dietary supplements and biologics) and populate the Accelerating Innovations for Mothers (AIM) database. This database was screened for all candidates that have been investigated for preterm birth. Candidates in clinical development were ranked against criteria from TPPs, and classified as high, medium or low potential. Preclinical candidates were categorised by product type, archetype and medicine subclass.

RESULTS

The AIM database identified 178 candidates. Of the 71 candidates in clinical development, ten were deemed high potential (Prevention: Omega-3 fatty acid, aspirin, vaginal progesterone, oral progesterone, L-arginine, and selenium; Treatment: nicorandil, isosorbide dinitrate, nicardipine and celecoxib) and seven were medium potential (Prevention: pravastatin and lactoferrin; Treatment: glyceryl trinitrate, retosiban, relcovaptan, human chorionic gonadotropin and Bryophyllum pinnatum extract). 107 candidates were in preclinical development.

CONCLUSIONS

This analysis provides a drug-agnostic approach to assessing the potential of candidate medicines for spontaneous preterm birth. Research should be prioritised for high-potential candidates that are most likely to meet the real world needs of women, babies, and health care professionals.

Systematic evaluation of the pre-eclampsia drugs, dietary supplements and biologicals pipeline using target product profiles

BACKGROUND

The Accelerating Innovation for Mothers (AIM) project established a database of candidate medicines in research and development (R&amp;D) between 2000 and 2021 for five pregnancy-related conditions, including pre-eclampsia. In parallel, we published target product profiles (TPPs) that describe optimal characteristics of medicines for use in preventing/treating pre-eclampsia. The study objective was to use systematic double screening and extraction to identify all candidate medicines being investigated for pre-eclampsia prevention/treatment and rank their potential based on the TPPs.

METHODS

Adis Insight, Pharmaprojects, WHO international clinical trials registry platform (ICTRP), PubMed and grant databases were searched (Jan-May 2021). The AIM database was screened for all candidates being investigated for pre-eclampsia. Candidates in clinical development were evaluated against nine prespecified criteria from TPPs identified as key for wide-scale implementation, and classified as high, medium or low potential based on matching to the TPPs. Preclinical candidates were categorised by product type, archetype and medicine subclass.

RESULTS

The AIM database identified 153 candidates for pre-eclampsia. Of the 87 candidates in clinical development, seven were classified as high potential (prevention: esomeprazole, L-arginine, chloroquine, vitamin D and metformin; treatment: sulfasalazine and metformin) and eight as medium potential (prevention: probiotic lactobacilli, dalteparin, selenium and omega-3 fatty acid; treatment: sulforaphane, pravastatin, rosuvastatin and vitamin B3). Sixty-six candidates were in preclinical development, the most common being amino acid/peptides, siRNA-based medicines and polyphenols.

CONCLUSIONS

This is a novel, evidence-informed approach to identifying promising candidates for pre-eclampsia prevention and treatment - a vital step in stimulating R&amp;D of new medicines for pre-eclampsia suitable for real-world implementation.

Polyphenols for the Prevention or Management of Preeclampsia: A Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate the effects of polyphenol-containing products during pregnancy on preeclampsia-related maternal and neonatal outcomes.

DESIGN

Systematic review and meta-analysis.

SETTING

Nine databases and one trial registry, from inception to August 11th, 2023.

POPULATION/SAMPLE

Randomised controlled trials where women received polyphenolic-containing products (as standardised extracts or dietary supplements) compared to placebo or standard care.

METHODS

All review stages were conducted by two independent reviewers. Random-effects meta-analysis with the Hartung-Knapp-Sidik-Jonkman method using a framework for studies with few events.

MAIN OUTCOME MEASURES

Clinical outcomes combining the core outcome set for preeclampsia and WHO's priority outcomes.

RESULTS

Fourteen trials investigating six candidates were included. In women with preeclampsia, the addition of epigallocatechin gallate (EGCG) to nifedipine may reduce the time needed to achieve blood pressure control (mean difference (MD) = -14.10 min, 95% CI -18.46 to -9.74) and increase the time to the next hypertensive crisis (MD = 3.10 h, 95% CI 2.35 to 3.85) compared to nifedipine alone (1 trial, 349 women; low certainty). Similarly, the addition of resveratrol to nifedipine may reduce the time needed to achieve blood pressure control (MD = -15.50 min, 95% CI -19.83 to -11.17) and increase the time to the next hypertensive crisis (MD = 2.50 h, 95% CI 2.09 to 2.91) (1 trial, 349 women; low certainty). No differences were observed for other outcomes or candidates (Salvia miltiorrhiza, Bryophyllum pinnatum , raspberry and cranberry extracts).

CONCLUSIONS

ECGC and resveratrol supplements have been investigated for potential effects in managing clinical signs and symptoms of preeclampsia; however, evidence on the clinical and adverse effects of polyphenols is limited and uncertain.

Effectiveness of care bundles for prevention and treatment of postpartum hemorrhage: a systematic review

OBJECTIVE

Care bundles are a promising approach to reducing postpartum hemorrhage-related morbidity and mortality. We assessed the effectiveness and safety of care bundles for postpartum hemorrhage prevention and/or treatment.

DATA SOURCES

We searched MEDLINE, Embase, Cochrane CENTRAL, Maternity and Infant Care Database, and Global Index Medicus (inception to June 9, 2023) and ClinicalTrials.gov and the International Clinical Trials Registry Platform (last 5 years) using a phased search strategy, combining terms for postpartum hemorrhage and care bundles.

STUDY ELIGIBILITY CRITERIA

Peer-reviewed studies evaluating postpartum hemorrhage-related care bundles were included. Care bundles were defined as interventions comprising ≥3 components implemented collectively, concurrently, or in rapid succession. Randomized and nonrandomized controlled trials, interrupted time series, and before-after studies (controlled or uncontrolled) were eligible.

METHODS

Risk of bias was assessed using RoB 2 (randomized trials) and ROBINS-I (nonrandomized studies). For controlled studies, we reported risk ratios for dichotomous outcomes and mean differences for continuous outcomes, with certainty of evidence determined using GRADE. For uncontrolled studies, we used effect direction tables and summarized results narratively.

RESULTS

Twenty-two studies were included for analysis. For prevention-only bundles (2 studies), low-certainty evidence suggests possible benefits in reducing blood loss, duration of hospitalization, and intensive care unit stay, and maternal well-being. For treatment-only bundles (9 studies), high-certainty evidence shows that the E-MOTIVE intervention reduced risks of composite severe morbidity (risk ratio, 0.40; 95% confidence interval, 0.32-0.50) and blood transfusion for bleeding, postpartum hemorrhage, severe postpartum hemorrhage, and mean blood loss. One nonrandomized trial and 7 uncontrolled studies suggest that other postpartum hemorrhage treatment bundles might reduce blood loss and severe postpartum hemorrhage, but this is uncertain. For combined prevention/treatment bundles (11 studies), low-certainty evidence shows that the California Maternal Quality Care Collaborative care bundle may reduce severe maternal morbidity (risk ratio, 0.64; 95% confidence interval, 0.57-0.72). Ten uncontrolled studies variably showed possible benefits, no effects, or harms for other bundle types. Nearly all uncontrolled studies did not use suitable statistical methods for single-group pretest-posttest comparisons and should thus be interpreted with caution.

CONCLUSION

The E-MOTIVE intervention improves postpartum hemorrhage-related outcomes among women delivering vaginally, and the California Maternal Quality Care Collaborative bundle may reduce severe maternal morbidity. Other bundle designs warrant further effectiveness research before implementation is contemplated.

The drug drought in maternal health: an ongoing predicament

We developed a comprehensive database of medicines that are used or are being investigated for pre-eclampsia or eclampsia, preterm birth or labour, postpartum haemorrhage, intrauterine growth restriction, and fetal distress and that were in active development between 2000 and 2021. A total of 444 candidates were identified: approximately half of candidates were in active development, two-thirds had been repurposed after initially being used for another condition, and just under half were in preclinical studies. Only 64 candidates were in active late-stage (phase 3) development as of Oct 25, 2021, and given the slow pace of biomedical development, it could take years before any of these products eventually make it to market. A lack of innovation for maternal health medicines persists, and the market continues to fail pregnant individuals. There is a need for collective action from all relevant stakeholders to accelerate investment in the development of new or improved medicines for pregnancy-related conditions.

Expert consensus on novel medicines to prevent preterm birth and manage preterm labour: Target product profiles

OBJECTIVE

To develop target product profiles (TPPs) for new medicines for preterm birth prevention and preterm labour management that address the real-world need of women and healthcare providers, informed by views and agreement amongst globally diverse stakeholders.

DESIGN

Mixed methods.

SETTING

Global (with a focus on low- and middle-income countries, LMICs).

SAMPLE

Global stakeholders with diverse expertise in preterm labour/birth and drug development.

METHODS

Following an initial literature review, diverse stakeholders were invited to participate in an online international survey and in-depth interviews. The level of stakeholder agreement with TPPs was assessed, and findings from interviews were synthesised to inform the final TPPs.

MAIN OUTCOMES MEASURES

Level of stakeholder agreement on the minimum and preferred requirements for preterm labour/birth medicines.

RESULTS

We performed 21 interviews. Interview participants demonstrated strong agreement on room temperature stability, no additional drug-specific clinical monitoring, and affordability in LMICs being the minimal acceptable requirements. Points of discussion were raised around the target population. Survey respondents included clinicians, researchers, funding agency staff, international public organisation staff, programme implementers, policymakers, representatives of consumer advocacy organisations and other relevant stakeholders from maternal health systems. Survey results indicated strong agreement amongst stakeholders, with only one variable in each TPP not reaching consensus (i.e. 25% disagree or strongly disagree).

CONCLUSIONS

There is strong consensus within the preterm labour/birth community on the characteristics that new medicines for preterm birth prevention and preterm labour management must achieve. These TPPs provide necessary guidance to evaluate new candidates and their potential for implementation in a range of settings.

L-Arginine and L-Citrulline for Prevention and Treatment of Pre-Eclampsia: A Systematic Review and Meta-Analysis

BACKGROUND

Evidence suggests L-arginine may be effective at reducing pre-eclampsia and related outcomes. However, whether L-arginine can prevent or only treat pre-eclampsia, and thus the target population and timing of initiation, remains unknown.

OBJECTIVES

To evaluate the effects of L-arginine and L-citrulline (precursor of L-arginine) on the prevention and treatment of pre-eclampsia.

SEARCH STRATEGY

MEDLINE, Embase, CINAHL, Global Index Medicus and the Cochrane Library were searched through 7 February 2024.

SELECTION CRITERIA

Trials administering L-arginine or L-citrulline to pregnant women, with the comparison group receiving placebo or standard care, were included.

DATA COLLECTION AND ANALYSIS

Meta-analyses were conducted separately for prevention or treatment trials, using random-effects models.

MAIN RESULTS

Twenty randomised controlled trials (RCTs) (2028 women) and three non-randomised trials (189 women) were included. The risk of bias was 'high' in eight RCTs and showed 'some concerns' in 12. In prevention trials, L-arginine was associated with a reduced risk of pre-eclampsia (relative risk [RR] 0.52; 95% confidence interval [CI], 0.35, 0.78; low-certainty evidence, four trials) and severe pre-eclampsia (RR 0.23; 95% CI, 0.09, 0.55; low-certainty evidence, three trials). In treatment trials, L-arginine may reduce mean systolic blood pressure (MD -5.64 mmHg; 95% CI, -10.66, -0.62; very low-certainty evidence, three trials) and fetal growth restriction (RR 0.46; 95% CI, 0.26, 0.81; low-certainty evidence, two trials). Only one study (36 women) examined L-citrulline and reported no effect on pre-eclampsia or blood pressure.

CONCLUSIONS

L-arginine may be promising for pre-eclampsia prevention and treatment, but findings should be interpreted cautiously. More trials are needed to determine the optimal dose and time to commence supplementation and support clinical decision-making.