Long-Term Intracellular Tracking of Label-Free Nanoparticles in Live Cells and Tissues with Confocal Microscopy

The label-free imaging of inorganic nanoparticles (NPs) using confocal laser scanning microscopy (CLSM) provides a powerful and versatile tool for studying interactions between NPs and biological systems. Without the need for exogenous labels or markers, it simply benefits from the differential scattering of visible photons between biomaterials and inorganic NPs. Validation experiments conducted on fixed and living cells in real-time, as well as mouse tissue sections following parenteral administration of NPs. Additionally, by incorporating reporter fluorophores and utilizing both reflectance and fluorescence imaging modalities, the method enables high-resolution multiplex imaging of cellular structures and NPs. Different sizes and concentrations of Au NPs are tested as for Ag, Fe3O4, and CeO2 NPs, all with biological interest. Overall, the comprehensive study of NP imaging by confocal microscopy in reflectance mode provides valuable insights and tools for researchers interested in monitoring the nano-bio interactions.

Exploring the Long-Term Tissue Accumulation and Excretion of 3 nm Cerium Oxide Nanoparticles after Single Dose Administration

Nanoparticle (NP) pharmacokinetics significantly differ from traditional small molecule principles. From this emerges the need to create new tools and concepts to harness their full potential and avoid unnecessary risks. Nanoparticle pharmacokinetics strongly depend on size, shape, surface functionalisation, and aggregation state, influencing their biodistribution, accumulation, transformations, and excretion profile, and hence their efficacy and safety. Today, while NP biodistribution and nanoceria biodistribution have been studied often at short times, their long-term accumulation and excretion have rarely been studied. In this work, 3 nm nanoceria at 5.7 mg/kg of body weight was intravenously administrated in a single dose to healthy mice. Biodistribution was measured in the liver, spleen, kidney, lung, brain, lymph nodes, ovary, bone marrow, urine, and faeces at different time points (1, 9, 30, and 100 days). Biodistribution and urinary and faecal excretion were also studied in rats placed in metabolic cages at shorter times. The similarity of results of different NPs in different models is shown as the heterogeneous nanoceria distribution in organs. After the expectable accumulation in the liver and spleen, the concentration of cerium decays exponentially, accounting for about a 50% excretion of cerium from the body in 100 days. Cerium ions, coming from NP dissolution, are most likely excreted via the urinary tract, and ceria nanoparticles accumulated in the liver are most likely excreted via the hepatobiliary route. In addition, nanoceria looks safe and does not damage the target organs. No weight loss or apathy was observed during the course of the experiments.

Nanoceria dissolution at acidic pH by breaking off the catalytic loop

This manuscript proves the reproducibility and robustness of cerium oxide nanoparticles, nanoceria, employed as a chemical reagent with oxidizing capacity (as an electron sink) at acidic pH. Unlike nanoceria multi-enzyme-mimetic capabilities at neutral or high pH, nanoceria can behave as a stoichiometric reagent at low pH where insoluble Ce⁴⁺ ions transform into soluble Ce³⁺ in the nanocrystal that finally dissolves. This behaviour can be interpreted as enzyme-like when nanoceria is in excess with respect to the substrate. Under these conditions, the Ce³⁺/Ce⁴⁺ ratio in the NPs can easily be estimated by titration with ferrocyanide. This procedure could become a rapid assessment tool for evaluating nanoceria capacity in liquid environments.

How Does Immunomodulatory Nanoceria Works? ROS and Immunometabolism

Dysregulation of the immune system is associated with an overproduction of metabolic reactive oxygen species (ROS) and consequent oxidative stress. By buffering excess ROS, cerium oxide (CeO₂) nanoparticles (NPs) (nanoceria) not only protect from oxidative stress consequence of inflammation but also modulate the immune response towards inflammation resolution. Immunomodulation is the modulation (regulatory adjustment) of the immune system. It has natural and human-induced forms, and it is part of immunotherapy, in which immune responses are induced, amplified, attenuated, or prevented according to therapeutic goals. For decades, it has been observed that immune cells transform from relative metabolic quiescence to a highly active metabolic state during activation(1). These changes in metabolism affect fate and function over a broad range of timescales and cell types, always correlated to metabolic changes closely associated with mitochondria number and morphology. The question is how to control the immunochemical potential, thereby regulating the immune response, by administering cellular power supply. In this regard, immune cells show different general catabolic modes relative to their activation status, linked to their specific functions (maintenance, scavenging, defense, resolution, and repair) that can be correlated to different ROS requirements and production. Properly formulated, nanoceria is highly soluble, safe, and potentially biodegradable, and it may overcome current antioxidant substances limitations and thus open a new era for human health management.

Stable anchoring of bacteria-based protein nanoparticles for surface enhanced cell guidance

In tissue engineering, biological, physical, and chemical inputs have to be combined to properly mimic cellular environments and successfully build artificial tissues which can be designed to fulfill different biomedical needs such as the shortage of organ donors or the development of in vitro disease models for drug testing. Inclusion body-like protein nanoparticles (pNPs) can simultaneously provide such physical and biochemical stimuli to cells when attached to surfaces. However, this attachment has only been made by physisorption. To provide a stable anchoring, a covalent binding of lactic acid bacteria (LAB) produced pNPs, which lack the innate pyrogenic impurities of Gram-negative bacteria like Escherichia coli, is presented. The reported micropatterns feature a robust nanoscale topography with an unprecedented mechanical stability. In addition, they are denser and more capable of influencing cell morphology and orientation. The increased stability and the absence of pyrogenic impurities represent a step forward towards the translation of this material to a clinical setting.

Does the presence of placental basal plate myometrial fibres increase the risk of subsequent morbidly adherent placenta: a case-control study

OBJECTIVE

Antenatal diagnosis of morbidly adherent placenta has been shown to improve outcomes, but existing predictors lack sensitivity. Our objective was to determine whether the presence of myometrial fibres attached to the placental basal plate (BPMYO) in an antecedent pregnancy is associated with subsequent morbidly adherent placenta.

DESIGN

A case-control study.

SETTING

Departments of Obstetrics and Gynecology and Pathology, Northwestern University, Chicago, IL, USA.

SAMPLE

Women who had at least two pregnancies with placental pathological evaluation.

METHODS

Cases were defined as women with evidence of morbidly adherent placenta (both clinically and pathologically) in their most recent pregnancy whereas women without evidence of morbidly adherent placenta served as controls. Pathological specimens of placentas from previous pregnancies were evaluated for BPMYO. The presence of BPMYO on a previous placenta was evaluated to determine whether it could be used to improve the antenatal diagnosis of morbidly adherent placenta.

RESULTS

Of the 25 cases of morbidly adherent placenta, 19 (76%) had BPMYO present on their previous placenta compared with 41 (41%) of controls (odds ratio 4.8, 95% CI 1.8-13.0). Adding BPMYO to a regression including other risk factors for morbidly adherent placenta (i.e. maternal age, number of previous caesarean sections, placenta praevia, previous multiple gestation, any previous curettage, and ultrasonographic suspicion of placenta accreta) significantly improved the sensitivity of antenatal diagnosis of morbidly adherent placenta (61% versus 39%, P < 0.001) without a change in specificity (97% versus 97%, P = 1.00).

CONCLUSION

BPMYO on previous placental pathology is associated with an increased risk of morbidly adherent placenta in a subsequent pregnancy. These findings may shed light on the pathophysiology of accreta and inform future research on predictors of accreta.

TWEETABLE ABSTRACT

Previous basal plate myometrium improves the ability to detect subsequent morbidly adherent placenta.

Stillbirth: Genome-wide copy number variation profiling in archived placental umbilical cord samples with pathologic and clinical correlation

INTRODUCTION

Stillbirth remains a devastating health issue with 26,000 stillbirths occurring annually in the United States. Formalin-fixed, paraffin-embedded (FFPE) umbilical cord samples are available for many stillbirths. Our aim was to validate the use of these samples in identifying genetic variations in stillbirth through microarray analysis.

METHODS

This is a retrospective case-control study from a single institution of stillbirths ≥ 23 weeks gestational age and control liveborn infants. Fetal genomic DNA was extracted from FFPE umbilical cord samples of stillborn and control placentas, and genotyping was performed using the Illumina HumanOmniExpresss-12v1 Beadchip. Array results were verified with qPCR.

RESULTS

31 case-specific CNVs (17 deletions and 14 amplifications) with an average size of 294 kb for amplifications and 74 kb for deletions were identified among 94 FFPE samples (86 cases; 8 controls). In total 38 (44%) of the stillbirth samples had a CNV detected. Validation of a subset of microarray findings with qPCR confirmed deletions on 1p (2 cases), 11q (4 cases) and amplifications on 18 (1 case). Placental underperfusion changes were seen in stillborns with deletions on 1p, a region containing complement regulatory genes which have been shown to play a role in preeclampsia.

DISCUSSION

This study validated the use of archived FFPE umbilical cord samples for genome-wide copy number profiling in stillbirths, and demonstrates specific CNV deletions and amplifications. Microarray analysis in an expanded cohort of stillbirth FFPE samples has the potential to identify biomarkers involved in stillbirth pathogenesis.

Mutations in FAM20C are associated with lethal osteosclerotic bone dysplasia (Raine syndrome), highlighting a crucial molecule in bone development

The generation and homeostasis of bone tissue throughout development and maturity is controlled by the carefully balanced processes of bone formation and resorption. Disruption of this balance can give rise to a broad range of skeletal pathologies. Lethal osteosclerotic bone dysplasia (or, Raine syndrome) is an autosomal recessive disorder characterized by generalized osteosclerosis with periosteal bone formation and a distinctive facial phenotype. Affected individuals survive only days or weeks. We have identified and defined a chromosome 7 uniparental isodisomy and a 7p telomeric microdeletion in an affected subject. The extent of the deleted region at the 7p telomere was established by genotyping microsatellite markers across the telomeric region. The region is delimited by marker D7S2563 and contains five transcriptional units. Sequence analysis of FAM20C, located within the deleted region, in six additional affected subjects revealed four homozygous mutations and two compound heterozygotes. The identified mutations include four nonsynonymous base changes, all affecting evolutionarily conserved residues, and four splice-site changes that are predicted to have a detrimental effect on splicing. FAM20C is a member of the FAM20 family of secreted proteins, and its mouse orthologue (DMP4) has demonstrated calcium-binding properties; we also show by in situ hybridization its expression profile in mineralizing tissues during development. This study defines the causative role of FAM20C in this lethal osteosclerotic disorder and its crucial role in normal bone development.

Intraplacental smooth muscle tumor: a case report

We present the second reported case of a smooth muscle neoplasm involving the placental parenchyma. On gross examination, the tumor easily separated from the uterus and had a whorled cut surface with finger-like extensions into the villous parenchyma, very similar to the previously described case. The differential diagnosis included a primary smooth muscle tumor of the placenta (placental leiomyoma), a primary uterine neoplasm incorporated into the placenta, and a metastatic sarcoma. In this case, the infant was male, and the polymerase chain reaction technique demonstrated the presence of Y chromosome gene in the placental parenchyma and its absence in the placental neoplasm. Thus, this neoplasm, despite its gross appearance of a primary placental tumor, actually represented an incorporated benign uterine leiomyoma.

Cell populations in the bone marrow of guinea pig fetuses with intrauterine growth retardation

Bone marrow smears and blood samples were examined in guinea pig fetuses in which intrauterine growth retardation (IUGR) had been induced by uterine artery ligation and compared with those of control (well-grown) fetuses from uterine horns with intact circulation. Differential bone marrow cell counts were obtained from a count of 300 cells per smear and blood samples were assayed for hemoglobin concentration and 2,3-diphosphoglycerate (DPG). Results of blood assays showed no difference in hemoglobin concentration. DPG levels were reduced in the IUGR guinea pigs (P < .05), which could be a consequence of decreased glucose availability or represent an adaptation to reduced oxygen availability. Comparisons of bone marrow counts revealed an increase in total erythrocyte precursors (P < .05) and a decrease in total granulocytic precursors (P < .05) in IUGR fetuses. Within the erythroid lineage there was a significant increase in late (orthochromatic) erythroblasts (P < .005) in the IUGR animals compared with control animals. The granulocytic lineage of the IUGR fetuses showed a significant decrease in mature neutrophils (P < .05) and eosinophilic precursors (P < .05) compared with controls. These data suggest that the hypoxic stress of uterine artery ligation leads to an increase in medullary erythropoiesis. In concert with a previous study that showed a reduction in hepatic erythropoiesis, these data suggest a precocious shift of the anatomic site of erythropoiesis from the liver to the bone marrow under conditions of hypoxia.

The very low birthweight infant: maternal complications leading to preterm birth, placental lesions, and intrauterine growth

The placental lesions of the very low birthweight (VLBW) infant were investigated in relation to clinical complications leading to preterm birth and evidence of growth impairment. The 249 singleton gestations yielding infants less than 1500 g were grouped according to the clinical complications leading to preterm birth as premature membrane rupture (116/249, 47%) preterm labor (55/249, 22%), pregnancy-induced hypertension (PIH, 54/249, 22%), and normotensive abruption (ABR, 24/249, 10%). Specifically excluded from this data set were cases with greater than 2 weeks discordance, fetal congenital anomalies, placenta previa, and maternal medical or gestational diseases such as chronic hypertension and diabetes mellitus, and intrauterine growth retardation (IUGR) as a primary indication for delivery. Placental weight and lesions including decidual vasculopathy and related villous lesions, chronic villitis/intervillositis, and decidual plasmacytosis were considered as variables in analyses in which raw birthweight was the dependent variable and gestational age a confounder. Of the 195 VLBW, 79 (41%) infants from normotensive mothers had lesions of decidual vasculopathy or chronic inflammation. In the VLBW infants from hypertensive mothers, growth restriction was related to markers of decidual vasculopathy. In the absence of maternal hypertension the growth restriction was independently associated with chronic villitis. Decidual vasculopathy (characteristic of PIH) and chronic intrauterine inflammation underlie the complications of many normotensive VLBW infants. The placental lesions in VLBW-IUGR depend on the presence or absence of maternal hypertension. In the absence of maternal hypertension, VLBW-IUGR is associated with chronic inflammation and is independent of decidual vasculopathy. In the presence of maternal hypertension, VLBW-IUGR is directly related to decidual vasculopathy.

Hepatic histology in intrauterine growth retardation following uterine artery ligation in the guinea pig

Hepatic histology was examined in guinea pig fetuses in which intrauterine growth retardation (IUGR) was induced by unilateral uterine artery ligation and compared with that of control (well-grown) fetuses from uterine horns with intact circulations. From all animals, sections taken from the six lobes of the liver were prepared using hematoxylin and eosin stains. Periodic acid-Schiff and Prussian blue stains (both on fixed samples) and Oil Red O stains on frozen tissues were performed on a subset of samples. Comparisons revealed greater fat content in hepatocytes (P < .05) and decreased total hepatic hematopoiesis (P < .01) in IUGR animals than in controls. No differences in hepatocyte histology among lobes were observed in control animals. IUGR animals had increased fat content and decreased extramedullary hematopoiesis in the lobes receiving the portal circulation (P < .05). These data indicate significant abnormalities of hepatic lipid metabolism in IUGR animals following uterine artery ligation. An unexpected and counterintuitive finding was the decrease in hepatic hematopoiesis in the right side of the liver.