Time-course characterization of whole-transcriptome dynamics of HepG2/C3A spheroids and its toxicological implications

Physiologically relevant in vitro models are a priority in predictive toxicology to replace and/or reduce animal experiments. The compromised toxicant metabolism of many immortalized human liver cell lines grown as monolayers as compared to in vivo metabolism limits their physiological relevance. However, recent efforts to culture liver cells in a 3D environment, such as spheroids, to better mimic the in vivo conditions, may enhance the toxicant metabolism of human liver cell lines. In this study, we characterized the dynamic changes in the transcriptome of HepG2/C3A hepatocarcinoma cell spheroids maintained in a clinostat system (CelVivo) to gain insight into the metabolic capacity of this model as a function of spheroid size and culture time. We assessed morphological changes (size, necrotic core), cell health, and proliferation rate from initial spheroid seeding to 35 days of continuous culture in conjunction with a time-course (0, 3, 7, 10, 14, 21, 28 days) of the transcriptome (TempO-Seq, BioSpyder). The phenotypic characteristics of HepG2/C3A growing in spheroids were comparable to monolayer growth until ~Day 12 (Day 10-14) when a significant decrease in cell doubling rate was noted which was concurrent with down-regulation of cell proliferation and cell cycle pathways over this time period. Principal component analysis of the transcriptome data suggests that the Day 3, 7, and 10 spheroids are pronouncedly different from the Day 14, 21, and 28 spheroids in support of a biological transition time point during the long-term 3D spheroid cultures. The expression of genes encoding cellular components involved in toxicant metabolism and transport rapidly increased during the early time points of spheroids to peak at Day 7 or Day 10 as compared to monolayer cultures with a gradual decrease in expression with further culture, suggesting the most metabolically responsive time window for exposure studies. Overall, we provide baseline information on the cellular and molecular characterization, with a particular focus on toxicant metabolic capacity dynamics and cell growth, of HepG2/C3A 3D spheroid cultures over time.

Systematic evaluation of high-throughput PBK modelling strategies for the prediction of intravenous and oral pharmacokinetics in humans

Physiologically based kinetic (PBK) modelling offers a mechanistic basis for predicting the pharmaco-/toxicokinetics of compounds and thereby provides critical information for integrating toxicity and exposure data to replace animal testing with in vitro or in silico methods. However, traditional PBK modelling depends on animal and human data, which limits its usefulness for non-animal methods. To address this limitation, high-throughput PBK modelling aims to rely exclusively on in vitro and in silico data for model generation. Here, we evaluate a variety of in silico tools and different strategies to parameterise PBK models with input values from various sources in a high-throughput manner. We gather 2000 + publicly available human in vivo concentration-time profiles of 200 + compounds (IV and oral administration), as well as in silico, in vitro and in vivo determined compound-specific parameters required for the PBK modelling of these compounds. Then, we systematically evaluate all possible PBK model parametrisation strategies in PK-Sim and quantify their prediction accuracy against the collected in vivo concentration-time profiles. Our results show that even simple, generic high-throughput PBK modelling can provide accurate predictions of the pharmacokinetics of most compounds (87% of Cmax and 84% of AUC within tenfold). Nevertheless, we also observe major differences in prediction accuracies between the different parameterisation strategies, as well as between different compounds. Finally, we outline a strategy for high-throughput PBK modelling that relies exclusively on freely available tools. Our findings contribute to a more robust understanding of the reliability of high-throughput PBK modelling, which is essential to establish the confidence necessary for its utilisation in Next-Generation Risk Assessment.

Structure-specific variation in per- and polyfluoroalkyl substances toxicity among genetically diverse Caenorhabditis elegans strains

Background

There are >14,500 structurally diverse per- and polyfluoroalkyl substances (PFAS). Despite knowledge that these "forever chemicals" are in 99% of humans, mechanisms of toxicity and adverse health effects are incompletely known. Furthermore, the contribution of genetic variation to PFAS susceptibility and health consequences is unknown.

Objectives

We determined the toxicity of a structurally distinct set of PFAS in twelve genetically diverse strains of the genetic model system Caenorhabditis elegans.

Methods

Dose-response curves for four perfluoroalkyl carboxylic acids (PFNA, PFOA, PFPeA, and PFBA), two perfluoroalkyl sulfonic acids (PFOS and PFBS), two perfluoroalkyl sulfonamides (PFOSA and PFBSA), two fluoroether carboxylic acids (GenX and PFMOAA), one fluoroether sulfonic acid (PFEESA), and two fluorotelomers (6:2 FCA and 6:2 FTS) were determined in the C. elegans laboratory reference strain, N2, and eleven genetically diverse wild strains. Body length was quantified by image analysis at each dose after 48 hr of developmental exposure of L1 arrest-synchronized larvae to estimate effective concentration values (EC50).

Results

There was a significant range in toxicity among PFAS: PFOSA > PFBSA ≈ PFOS ≈ PFNA > PFOA > GenX ≈ PFEESA > PFBS ≈ PFPeA ≈ PFBA. Long-chain PFAS had greater toxicity than short-chain, and fluorosulfonamides were more toxic than carboxylic and sulfonic acids. Genetic variation explained variation in susceptibility to PFBSA, PFOS, PFBA, PFOA, GenX, PFEESA, PFPeA, and PFBA. There was significant variation in toxicity among C. elegans strains due to chain length, functional group, and between legacy and emerging PFAS.

Conclusion

C. elegans respond to legacy and emerging PFAS of diverse structures, and this depends on specific structures and genetic variation. Harnessing the natural genetic diversity of C. elegans and the structural complexity of PFAS is a powerful New Approach Methodology (NAM) to investigate structure-activity relationships and mechanisms of toxicity which may inform regulation of other PFAS to improve human and environmental health.

The Role of Nonhuman Primates in Neurotoxicology Research: Preclinical Models and Experimental Methods

Although noteworthy progress has been made in developing alternatives to animal testing, nonhuman primates still play a critical role in advancing biomedical research and will likely do so for many years. Core similarities between monkeys and humans in genetics, physiology, reproduction, development, and behavior make them excellent models for translational studies relevant to human health. This unit is designed to specifically address the role of nonhuman primates in neurotoxicology research and outlines the specialized assessments that can be used to measure exposure-related changes at the structural, chemical, cellular, molecular, and functional levels. © 2023 Wiley Periodicals LLC.

Development of an adverse outcome pathway network for breast cancer: a comprehensive representation of the pathogenesis, complexity and diversity of the disease

Adverse outcome pathways (AOPs), introduced in modern toxicology, intend to provide an evidence-based representation of toxicological effects and facilitate safety assessment of chemicals not solely based on laboratory animal in vivo experiments. However, some toxicological processes are too complicated to represent in one AOP. Therefore, AOP networks are developed that help understanding and predicting toxicological processes where complex exposure scenarios interact and lead to the emergence of the adverse outcome. In this study, we present an AOP network for breast cancer, developed after an in-depth survey of relevant scientific literature. Several molecular initiating events (MIE) were identified and various key events that link the MIEs with breast cancer were described. The AOP was developed according to Organization of Economic Co-Operation and Development (OECD) guidance, weight of evidence was assessed through the Bradford Hill criteria and confidence was tested by the OECD key questions. The AOP network provides a straightforward understanding of the disease onset and progression at different biological levels. It can be used to pinpoint knowledge gaps, identify novel therapeutic targets and act as a stepping stone for the development of novel in vitro test methods for hazard identification and risk assessment of newly developed chemicals and drugs.

Self-Emulsifying Drug Delivery Systems: An Alternative Approach to Improve Brain Bioavailability of Poorly Water-Soluble Drugs through Intranasal Administration

Efforts in discovering new and effective neurotherapeutics are made daily, although most fail to reach clinical trials. The main reason is their poor bioavailability, related to poor aqueous solubility, limited permeability through biological membranes, and the hepatic first-pass metabolism. Nevertheless, crossing the blood–brain barrier is the major drawback associated with brain drug delivery. To overcome it, intranasal administration has become more attractive, in some cases even surpassing the oral route. The unique anatomical features of the nasal cavity allow partial direct drug delivery to the brain, circumventing the blood–brain barrier. Systemic absorption through the nasal cavity also avoids the hepatic first-pass metabolism, increasing the systemic bioavailability of highly metabolized entities. Nevertheless, most neurotherapeutics present physicochemical characteristics that require them to be formulated in lipidic nanosystems as self-emulsifying drug delivery systems (SEDDS). These are isotropic mixtures of oils, surfactants, and co-surfactants that, after aqueous dilution, generate micro or nanoemulsions loading high concentrations of lipophilic drugs. SEDDS should overcome drug precipitation in absorption sites, increase their permeation through absorptive membranes, and enhance the stability of labile drugs against enzymatic activity. Thus, combining the advantages of SEDDS and those of the intranasal route for brain delivery, an increase in drugs’ brain targeting and bioavailability could be expected. This review deeply characterizes SEDDS as a lipidic nanosystem, gathering important information regarding the mechanisms associated with the intranasal delivery of drugs loaded in SEDDS. In the end, in vivo results after SEDDS intranasal or oral administration are discussed, globally revealing their efficacy in comparison with common solutions or suspensions.

Rapid Detection of Direct Compound Toxicity and Trailing Detection of Indirect Cell Metabolite Toxicity in a 96-Well Fluidic Culture Device for Cell-Based Screening Environments: Tactics in Six Sigma Quality Control Charts

Microfluidic screening tools, in vitro, evolve amid varied scientific disciplines. One emergent technique, simultaneously assessing cell toxicity from a primary compound and ensuing cell-generated metabolites (dual-toxicity screening), entails in-line systems having sequentially aligned culture chambers. To explore dual-tox screens, we probe the dissemination of nutrients involving 1-way transport with upstream compound dosing, midstream cascading flows, and downstream cessation. Distribution of flow gives rise to broad concentration ranges of dosing compound (0→ICcompound100) and wide-ranging concentration ranges of generated cell metabolites (0→ICmetabolites100). Innately, single-pass unidirectional flow retains 1st pass informative traits across the network, composed of nine interconnected culture wells, preserving both compound and cell-secreted byproducts as data indicators in each adjacent culture chamber. Thereafter, to assess effective compound hepatotoxicity (0→ECcompound100) and simultaneously classify for cell-metabolite toxicity (0→ECmetabolite100), we reveal utility by analyzing culture viability against ramping exposures of acetaminophen (APAP) and nefazodone (NEF), compounds of hepatic significance. We then discern metabolite generation with an emphasis on amplification across µchannel multiwell sites. Lastly, using conventional cell functions as indicator tools to assess dual toxicity, we investigate a non-drug induced liver injury (non-DILI) compound and DILI compound. The technology is for predictive evaluations of new compound formulations, new chemical entities (NCE), or drugs that have previously failed testing for unresolved reasons.

A decade of toxicological trends: what the papers say

Here we look at popular trends and concepts in toxicology over the decade 2009-2019. The top 10 concepts included methodological approaches such as zebrafish and genomics as well as broader concepts such as personalized medicine and adverse outcome pathways. The total number and rank order for each of the top 10 were tracked year by year via PubMed with >9500 papers contributing to the analysis. The data revealed a slow upward trend in the number of papers across all the concepts from 260 in 2009 to >1700 in 2019. Zebrafish, genomics and personalized medicine remained in the top four slots since 2009 with zebrafish dominating the rankings over the entire decade. Genomics was a strong second until 2013 when it was displaced first by the microbiome in 2014 and secondly by personalized medicine in 2015. Other notable trends were the ascendancy of the microbiome and adverse outcome pathways and the descendancy of hormesis and the 3Rs (replacement, reduction and refinement of animals in testing). The observation that the top four slots have been static over the past 4 years suggests that new ideas are introduced and increase in popularity until they find their place in scientific culture. This may suggest that relatively new concepts such as artificial intelligence and microphysiological systems have yet to find their steady state in the rankings. Similarly, as a relatively new player in toxicology, the full impact of the human microbiome on drug efficacy and safety remains to be seen.

Bioethics: a look at animal testing in medicine and cosmetics in the UK

Using animals for cosmetics and medical tests has contributed towards a debate based on conflicting interests. Despite the efforts in justifying the value of animals in conducting analyses, this study seeks to elaborate whether or not it is rational to use animals as test subjects in medical and cosmetics fields. The value of animal life is at the core of the emotional conflicts that arise when animals become experimental subjects in medical and cosmetics fields. The aim of this study is to determine if there are ethical differences in the use of animal testing in medicine versus cosmetics. The research, through review and content analysis of the existing literature, compares and provides the outcomes of using animals in medical and cosmetics tests by examining studies conducted in the UK. The findings of this research indicated that animal testing is considered acceptable in the medical field only if there are no other alternatives, but is completely unacceptable in the cosmetics field. The study also provides recommendations in the form of alternatives that protect animals from cruelty and may benefit the different stakeholders and the society at large.

Titanium dioxide nanoparticles via oral exposure leads to adverse disturbance of gut microecology and locomotor activity in adult mice

Titanium dioxide nanoparticles (TiO₂NPs) have been widely used as food additives in daily life. However, the impact of oral intake of TiO₂NPs on the nervous system is largely unknown. In this study, 7-week-old mice were treated with either vehicle or TiO₂NPs suspension solution at 150 mg/kg by intragastric administration for 30 days. Our results demonstrated that oral exposure to TiO₂NPs resulted in aberrant excitement of enteric neurons, although unapparent pathological changes were observed in gut. We also found the richness and evenness of gut microbiota were remarkably decreased and the gut microbial community compositions were significantly changed in the TiO₂NP-treated group as compared with vehicle controls. Interestingly, oral exposure to TiO₂NPs was capable to induce the inhibitory effects on locomotor activity, but it did not lead to significant change on the spatial learning and memory ability. We further revealed the mechanism that TiO₂NPs could specifically cause locomotor dysfunction by elevating the excitement of enteric neuron, which might spread to brain via gut-brain communication by vagal pathway. However, inflammation response, enteric neurotransmitter 5-HT and major gut peptides might not be involved in this pathological process. Together, these findings provide valuable insights into the novel mechanism of TiO₂NP-induced neurotoxicity. Understanding the microbiota-gut-brain axis will provide the foundation for potential therapeutic or prevention approaches against TiO₂NP-induced gut and brain-related disorders.

Deep Learning-Based Structure-Activity Relationship Modeling for Multi-Category Toxicity Classification: A Case Study of 10K Tox21 Chemicals With High-Throughput Cell-Based Androgen Receptor Bioassay Data

Deep learning (DL) has attracted the attention of computational toxicologists as it offers a potentially greater power for in silico predictive toxicology than existing shallow learning algorithms. However, contradicting reports have been documented. To further explore the advantages of DL over shallow learning, we conducted this case study using two cell-based androgen receptor (AR) activity datasets with 10K chemicals generated from the Tox21 program. A nested double-loop cross-validation approach was adopted along with a stratified sampling strategy for partitioning chemicals of multiple AR activity classes (i.e., agonist, antagonist, inactive, and inconclusive) at the same distribution rates amongst the training, validation and test subsets. Deep neural networks (DNN) and random forest (RF), representing deep and shallow learning algorithms, respectively, were chosen to carry out structure-activity relationship-based chemical toxicity prediction. Results suggest that DNN significantly outperformed RF (p < 0.001, ANOVA) by 22–27% for four metrics (precision, recall, F-measure, and AUPRC) and by 11% for another (AUROC). Further in-depth analyses of chemical scaffolding shed insights on structural alerts for AR agonists/antagonists and inactive/inconclusive compounds, which may aid in future drug discovery and improvement of toxicity prediction modeling.

Identification of aldo-keto reductase (AKR7A1) and glutathione S-transferase pi (GSTP1) as novel renal damage biomarkers following exposure to mercury

The kidney is one of the main targets for toxicity induced by xenobiotics. Sensitive detection of early impairment is critical to assess chemical-associated renal toxicity. The aim of this study was to identify potential nephrotoxic biomarkers in rat kidney tissues after exposure to mercury (Hg), a representative nephrotoxicant, and to evaluate these new biomarkers employing in vivo and in vitro systems. Mercuric chloride was administered orally to Sprague-Dawley rats for 2 weeks. Proteomic analysis revealed that aldo-keto reductase (AKR7A1) and glutathione S-transferase pi (GSTP1) were significantly elevated in kidney after Hg exposure. While the levels of conventional nephrotoxic clinical markers including blood urea nitrogen and serum creatinine were not elevated, the mRNA and protein levels of AKR7A1 and GSTP1 were increased upon Hg exposure in a dose-dependent manner. The increases in AKR7A1 and GSTP1 were also observed in rat kidneys after an extended exposure for 6 weeks to low-dose Hg. In in vitro rat kidney proximal tubular cells, changes in AKR7A1 and GSTP1 levels correlated well with the extent of cytotoxicity induced by Hg, cadmium, or cisplatin. AKR7A1 and GSTP1 were identified as new candidates for Hg-induced nephrotoxicity, suggesting that these biomarkers have potential for evaluating or predicting nephrotoxicity.

Upregulation of calprotectin in mild IgE-mediated ovalbumin hypersensitivity

Calprotectin, also known as S100A8/A9, has been linked to gut inflammation caused by IgE-mediated food hypersensitivities, but the pathophysiologic abnormalities it causes remain to be determined. We created a mild food hypersensitivity model through oral gavage of ovalbumin in Norway brown rats without using immune adjuvant. Changes in the levels of calprotectin and inflammation-associated cytokines were then observed over time. We found that fecal calprotectin as well as jejunal and liver TLR4, TNF-α, NF-κB, IL-1β, and IL-6 were upregulated in hypersensitive rats. Additionally, the influence of calprotectin on CD4⁺ T and dendritic cells was observed by co-culturing CD4⁺ T cells with dendritic cells, which revealed a shift toward increased Th2 T cells in calprotectin-treated cultures. These results suggest that calprotectin, along with other inflammatory factors, promotes the inflammation seen in mild food allergy.

Abuse liability assessment for biologic drugs - All molecules are not created equal

The development of novel drug candidates involves the thorough evaluation of potential efficacy and safety. To facilitate the safety assessment in light of global increases in prescription drug misuse/abuse, health authorities have developed guidance documents which provide a framework for evaluating the abuse liability of candidate therapeutics. The guidances do not distinguish between small molecules and biologics/biotherapeutics; however, there are key differences between these classes of therapeutics which are important drivers of concern for abuse. An analysis of these properties, including ability to distribute to the central nervous system, pharmacokinetic properties (e.g., half-life and metabolism), potential for off-target binding, and the physiochemical characteristics of biologic drug products suggests that the potential for abuse of a biologic is limited. Many marketed antibodies and recombinant proteins have been associated with adverse effects such as headache and dizziness. However, biologics have not historically engendered the rapid-onset psychoactive effects typically present for drugs of abuse, thus further underscoring their low risk for abuse potential. The factors to be taken into consideration before conducting nonclinical abuse liability studies with biologics are described herein; importantly, the aggregate assessment of these factors leads to the conclusion that abuse liability studies are unlikely to be necessary for this class of therapeutics.

Amniotic fluid stem cell models: A tool for filling the gaps in knowledge for human genetic diseases

Induced pluripotent stem (iPS) cells have attracted attention in recent years as a model of human genetic diseases. Starting from the diseased somatic cells isolated from an affected patient, iPS cells can be created and subsequently differentiated into various cell types that can be used to gain a better understanding of the disease at a cellular and molecular level. There are limitations of iPS cell generation, however, due to low efficiency, high costs, and lengthy protocols. The use of amniotic fluid stem cells (AFS) presents a worthy alternative as a stem cell source for modeling of human genetic diseases. Prenatal identification of chromosomal or Mendelian diseases may require the collection of amniotic fluid which is not only useful for the sake of diagnosis but also from this, AFS cells can be isolated and cultured. Since AFS cells show some characteristics of pluripotency, having the capacity to differentiate into various cell types derived from all three germ layers in vitro, they are a well-suited model for investigations regarding alterations in the molecular biology of a cell due to a specific genetic disease. This readily accessible source of stem cells can replace the necessity for generating iPS cells. Here, we expand on the applicability and importance of AFS cells as a model for discovery in the field of human genetic disease research. This paper is a review article. Referred literature in this paper has been listed in the references section. The data sets supporting the conclusions of this article are available online by searching various databases, including PubMed. Some original points in this article come from the laboratory practice in our research center and the authors’ experiences.

Development of bioluminescent chick chorioallantoic membrane (CAM) models for primary pancreatic cancer cells: a platform for drug testing

The aim of the present study was to develop chick-embryo chorioallantoic membrane (CAM) bioluminescent tumor models employing low passage cell cultures obtained from primary pancreatic ductal adenocarcinoma (PDAC) cells. Primary PDAC cells transduced with lentivirus expressing Firefly-luciferase (Fluc) were established and inoculated onto the CAM membrane, with >80% engraftment. Fluc signal reliably correlated with tumor growth. Tumor features were evaluated by immunohistochemistry and genetic analyses, including analysis of mutations and mRNA expression of PDAC pivotal genes, as well as microRNA (miRNA) profiling. These studies showed that CAM tumors had histopathological and genetic characteristic comparable to the original tumors. We subsequently tested the modulation of key miRNAs and the activity of gemcitabine and crizotinib on CAM tumors, showing that combination treatment resulted in 63% inhibition of tumor growth as compared to control (p < 0.01). These results were associated with reduced expression of miR-21 and increased expression of miR-155. Our study provides the first evidence that transduced primary PDAC cells can form tumors on the CAM, retaining several histopathological and (epi)genetic characteristics of original tumors. Moreover, our results support the use of these models for drug testing, providing insights on molecular mechanisms underlying antitumor activity of new drugs/combinations.

Meloxicam medication reduces orthodontically induced dental root resorption and tooth movement velocity: a combined in vivo and in vitro study of dental-periodontal cells and tissue

Non-steroidal anti-inflammatory drugs (NSAID) are used to alleviate pain sensations during orthodontic therapy but are also assumed to interfere with associated pseudo-inflammatory reactions. In particular, the effects of partially selective COX-2 inhibition over the constitutively expressed COX-1 (11:1) on periodontal cells and tissue, as induced by the NSAID meloxicam, remain unclear. We investigate possible adverse side-effects and potentially useful beneficial effects during orthodontic therapy and examine underlying cellular and tissue reactions. We randomly assigned 63 male Fischer344 rats to three consecutive experiments of 21 animals each (cone-beam computed tomography; histology/serology; reverse-transcription quantitative real-time polymerase chain reaction) in three experimental groups (n = 7; control; orthodontic tooth movement [OTM] of the first/second upper left molars [NiTi coil spring, 0.25 N]; OTM with a daily oral meloxicam dose of 3 mg/kg). In vitro, we stimulated human periodontal ligament fibroblasts (hPDL) with orthodontic pressure (2 g/cm²) with/without meloxicam (10 μM). In vivo, meloxicam significantly reduced serum C-reactive protein concentration, tooth movement velocity, orthodontically induced dentine root resorption (OIRR), osteoclast activity and the relative expression of inflammatory/osteoclast marker genes within the dental-periodontal tissue, while presenting good gastric tolerance. In vitro, we observed a corresponding significant decrease of prostaglandin E₂/interleukin-6/RANKL(-OPG) expression and of hPDL-mediated osteoclastogenesis. By inhibiting prostaglandin synthesis, meloxicam seems to downregulate hPDL-mediated inflammation, RANKL-induced osteoclastogenesis and, consequently, tooth movement velocity by about 50%, thus limiting its suitability for analgesia during orthodontic therapy. However, its protective effects regarding OIRR and good tolerance profile suggest future prophylactic application, which merits its further investigation.

Interactive effects of periodontitis and orthodontic tooth movement on dental root resorption, tooth movement velocity and alveolar bone loss in a rat model

BACKGROUND

Many adult orthodontic patients suffer from chronic periodontitis with recurrent episodes of active periodontal inflammation. As their number is steadily increasing, orthodontists are more and more frequently challenged by respective treatment considerations. However, little is currently known regarding interactive effects on undesired dental root resorption (DRR), tooth movement velocity, periodontal bone loss and the underlying cellular and tissue reactions.

MATERIAL AND METHODS

A total of 63 male Fischer344 rats were used in three consecutive experiments employing 21 animals each (A/B/C), randomly assigned to 3 experimental groups (n=7, 1/2/3), respectively: (A) CBCT; (B) histology/serology; (C) RT-qPCR-(1) control; (2) orthodontic tooth movement (OTM) of the first/second upper left molars (NiTi coil spring, 0.25N); (3) OTM with experimentally induced periodontitis (cervical silk ligature). After 14days of OTM, we quantified blood leukocyte level, DRR, osteoclast activity and relative gene expression of inflammatory and osteoclast marker genes within the dental-periodontal tissue as well as tooth movement velocity and periodontal bone loss after 14 and 28 days.

RESULTS

The experimentally induced periodontal bone loss was significantly increased by concurrent orthodontic force application. Periodontal inflammation during OTM on the other hand significantly augmented the extent of DRR, relative expression of inflammatory/osteoclast marker genes, blood leukocyte level and periodontal osteoclast activity. In addition, contrary to previous studies, we observed a significant increase in tooth movement velocity.

CONCLUSIONS

Although accelerated tooth movement would be favourable for orthodontic treatment, our results suggest that orthodontic interventions should only be performed after successful systematic periodontal therapy and paused in case of recurrent active inflammation.

Amniotic Fluid Stem Cells: A Novel Source for Modeling of Human Genetic Diseases

In recent years, great interest has been devoted to the use of Induced Pluripotent Stem cells (iPS) for modeling of human genetic diseases, due to the possibility of reprogramming somatic cells of affected patients into pluripotent cells, enabling differentiation into several cell types, and allowing investigations into the molecular mechanisms of the disease. However, the protocol of iPS generation still suffers from technical limitations, showing low efficiency, being expensive and time consuming. Amniotic Fluid Stem cells (AFS) represent a potential alternative novel source of stem cells for modeling of human genetic diseases. In fact, by means of prenatal diagnosis, a number of fetuses affected by chromosomal or Mendelian diseases can be identified, and the amniotic fluid collected for genetic testing can be used, after diagnosis, for the isolation, culture and differentiation of AFS cells. This can provide a useful stem cell model for the investigation of the molecular basis of the diagnosed disease without the necessity of producing iPS, since AFS cells show some features of pluripotency and are able to differentiate in cells derived from all three germ layers “in vitro”. In this article, we describe the potential benefits provided by using AFS cells in the modeling of human genetic diseases.