Ascorbate enhances elastin synthesis in 3D tissue-engineered pulmonary fibroblasts constructs

A roadmap for developing and engineering in vitro pulmonary fibrosis models

Idiopathic pulmonary fibrosis (IPF) is a severe form of pulmonary fibrosis. IPF is a fatal disease with no cure and is challenging to diagnose. Unfortunately, due to the elusive etiology of IPF and a late diagnosis, there are no cures for IPF. Two FDA-approved drugs for IPF, nintedanib and pirfenidone, slow the progression of the disease, yet fail to cure or reverse it. Furthermore, most animal models have been unable to completely recapitulate the physiology of human IPF, resulting in the failure of many drug candidates in preclinical studies. In the last few decades, the development of new IPF drugs focused on changes at the cellular level, as it was believed that the cells were the main players in IPF development and progression. However, recent studies have shed light on the critical role of the extracellular matrix (ECM) in IPF development, where the ECM communicates with cells and initiates a positive feedback loop to promote fibrotic processes. Stemming from this shift in the understanding of fibrosis, there is a need to develop in vitro model systems that mimic the human lung microenvironment to better understand how biochemical and biomechanical cues drive fibrotic processes in IPF. However, current in vitro cell culture platforms, which may include substrates with different stiffness or natural hydrogels, have shortcomings in recapitulating the complexity of fibrosis. This review aims to draw a roadmap for developing advanced in vitro pulmonary fibrosis models, which can be leveraged to understand better different mechanisms involved in IPF and develop drug candidates with improved efficacy. We begin with a brief overview defining pulmonary fibrosis and highlight the importance of ECM components in the disease progression. We focus on fibroblasts and myofibroblasts in the context of ECM biology and fibrotic processes, as most conventional advanced in vitro models of pulmonary fibrosis use these cell types. We transition to discussing the parameters of the 3D microenvironment that are relevant in pulmonary fibrosis progression. Finally, the review ends by summarizing the state of the art in the field and future directions.

The identification of metabolism-related subtypes and potential treatments for idiopathic pulmonary fibrosis

Background: Idiopathic pulmonary fibrosis (IPF) is caused by aberrant repair because of alveolar epithelial injury and can only be effectively treated with several compounds. Several metabolism-related biomolecular processes were found to be involved in IPF. We aimed to identify IPF subtypes based on metabolism-related pathways and explore potential drugs for each subtype. Methods: Gene profiles and clinical information were obtained from the Gene Expression Omnibus (GEO) database (GSE70867 and GSE93606). The enrichment scores for 41 metabolism-related pathways, immune cells, and immune pathways were calculated using the Gene Set Variation Analysis (GSVA) package. The ConsensusClusterPlus package was used to cluster samples. Novel modules and hub genes were identified using weighted correlation network analysis (WGCNA). Receiver operating characteristic (ROC) and calibration curves were plotted, and decision curve analysis (DCA) were performed to evaluate the model in the training and validation cohorts. A connectivity map was used as a drug probe. Results: Two subtypes with significant differences in prognosis were identified based on the metabolism-related pathways. Subtype C1 had a poor prognosis, low metabolic levels, and a unique immune signature. CDS2, LCLAT1, GPD1L, AGPAT1, ALDH3A1, LAP3, ADH5, AHCYL2, and MDH1 were used to distinguish between the two subtypes. Finally, subtype-specific drugs, which can potentially treat IPF, were identified. Conclusion: The aberrant activation of metabolism-related pathways contributes to differential prognoses in patients with IPF. Collectively, our findings provide novel mechanistic insights into subtyping IPF based on the metabolism-related pathway and potential treatments, which would help clinicians provide subtype-specific individualized therapeutic management to patients.

Colorectal Cancer Bioengineered Microtissues as a Model to Replicate Tumor-ECM Crosstalk and Assess Drug Delivery Systems In Vitro

Current 3D cancer models (in vitro) fail to reproduce complex cancer cell extracellular matrices (ECMs) and the interrelationships occurring (in vivo) in the tumor microenvironment (TME). Herein, we propose 3D in vitro colorectal cancer microtissues (3D CRC μTs), which reproduce the TME more faithfully in vitro. Normal human fibroblasts were seeded onto porous biodegradable gelatin microbeads (GPMs) and were continuously induced to synthesize and assemble their own ECMs (3D Stroma μTs) in a spinner flask bioreactor. Then, human colon cancer cells were dynamically seeded onto the 3D Stroma μTs to achieve the 3D CRC μTs. Morphological characterization of the 3D CRC μTs was performed to assess the presence of different complex macromolecular components that feature in vivo in the ECM. The results showed the 3D CRC μTs recapitulated the TME in terms of ECM remodeling, cell growth, and the activation of normal fibroblasts toward an activated phenotype. Then, the microtissues were assessed as a drug screening platform by evaluating the effect of 5-Fluorouracil (5-FU), curcumin-loaded nanoemulsions (CT-NE-Curc), and the combination of the two. When taken together, the results showed that our microtissues are promising in that they can help clarify complex cancer–ECM interactions and evaluate the efficacy of therapies. Moreover, they may be combined with tissue-on-chip technologies aimed at addressing further studies in cancer progression and drug discovery.

Extracellular Matrix Profiling and Disease Modelling in Engineered Vascular Smooth Muscle Cell Tissues

Aortic smooth muscle cells (SMCs) have an intrinsic role in regulating vessel homeostasis and pathological remodelling. In two-dimensional (2D) cell culture formats, however, SMCs are not embedded in their physiological extracellular matrix (ECM) environment. To overcome the limitations of conventional 2D SMC cultures, we established a 3D in vitro model of engineered vascular smooth muscle cell tissues (EVTs). EVTs were casted from primary murine aortic SMCs by suspending a SMC-fibrin master mix between two flexible silicon-posts at day 0 before prolonged culture up to 14 days. Immunohistochemical analysis of EVT longitudinal sections demonstrated that SMCs were aligned, viable and secretory. Mass spectrometry-based proteomics analysis of murine EVT lysates was performed and identified 135 matrisome proteins. Proteoglycans, including the large aggregating proteoglycan versican, accumulated within EVTs by day 7 of culture. This was followed by the deposition of collagens, elastin-binding proteins and matrix regulators up to day 14 of culture. In contrast to 2D SMC controls, accumulation of versican occurred in parallel to an increase in versikine, a cleavage product mediated by proteases of the A Disintegrin and Metalloproteinase with Thrombospondin motifs (ADAMTS) family. Next, we tested the response of EVTs to stimulation with transforming growth factor beta-1 (TGFβ-1). EVTs contracted in response to TGFβ-1 stimulation with altered ECM composition. In contrast, treatment with the pharmacological activin-like kinase inhibitor (ALKi) SB 431542 suppressed ECM secretion. As a disease stimulus, we performed calcification assays. The ECM acts as a nidus for calcium phosphate deposition in the arterial wall. We compared the onset and extent of calcification in EVTs and 2D SMCs cultured under high calcium and phosphate conditions for 7 days. Calcified EVTs displayed increased tissue stiffness by up to 30 % compared to non-calcified controls. Unlike the rapid calcification of SMCs in 2D cultures, EVTs sustained expression of the calcification inhibitor matrix Gla protein and allowed for better discrimination of the calcification propensity between independent biological replicates. In summary, EVTs are an intuitive and versatile model to investigate ECM synthesis and turnover by SMCs in a 3D environment. Unlike conventional 2D cultures, EVTs provide a more relevant pathophysiological model for retention of the nascent ECM produced by SMCs.

Hypoxia Induced Heparan Sulfate Primes the Extracellular Matrix for Endothelial Cell Recruitment by Facilitating VEGF-Fibronectin Interactions

Vascular endothelial growth factor-A (VEGF) is critical for the development, growth, and survival of blood vessels. Retinal pigmented epithelial (RPE) cells are a major source of VEGF in the retina, with evidence that the extracellular matrix (ECM)-binding forms are particularly important. VEGF associates with fibronectin in the ECM to mediate distinct signals in endothelial cells that are required for full angiogenic activity. Hypoxia stimulates VEGF expression and angiogenesis; however, little is known about whether hypoxia also affects VEGF deposition within the ECM. Therefore, we investigated the role of hypoxia in modulating VEGF-ECM interactions using a primary retinal cell culture model. We found that retinal endothelial cell attachment to RPE cell layers was enhanced in cells maintained under hypoxic conditions. Furthermore, we found that agents that disrupt VEGF-fibronectin interactions inhibited endothelial cell attachment to RPE cells. We also found that hypoxia induced a general change in the chemical structure of the HS produced by the RPE cells, which correlated to changes in the deposition of VEGF in the ECM, and we further identified preferential binding of VEGFR2 over VEGFR1 to VEGF laden-fibronectin matrices. Collectively, these results indicate that hypoxia-induced HS may prime fibronectin for VEGF deposition and endothelial cell recruitment by promoting VEGF-VEGFR2 interactions as a potential means to control angiogenesis in the retina and other tissues.

Efficacy of dermal redensification in chronoaged face: Quantitative volumetric assessment

BACKGROUND

Mesotherapy for chronoaged skin shows heterogeneous results.

OBJECTIVES

The aim of the study was to assess the efficacy of dermal redensification on the face and neck.

METHODS

Patients with mild-moderate-severe chronoaging of face and neck were included and, every 14 days, treated with four sessions of dermal redensification, consisting of 1 mL of hyaluronic acid (15 mg/mL) plus a dermo-restructuring complex. Skin improvements were analyzed at 8 weeks for amelioration by Wrinkle Severity Rating Scale and quantification of superficial wrinkles and texture by high-resolution 3D camera. All patients underwent a self-assessment questionnaire and Global Aesthetic Improvement Scale.

RESULTS

Thirty-six patients were enrolled (median age 55 [42-67] years). Eight weeks after treatment all patients reported a significant improvement, being Global Aesthetic Improvement Scale ≥2 in 69% of the subjects. Patients' perception of improvement of their skin quality was highly satisfactory in all items explored on the self-assessment questionnaire relating to radiance, elasticity, texture, and smoothness. Subjects with fine and moderate/deep wrinkles had an improvement >25% and 50%, respectively. Quantification of wrinkles with filters for superficial plane (1 mm) showed a statistically significant median decrease, both in width (1.53 [1.41-1.72] mm vs 1.27 [1.12-1.34] P < 0.001) and depth (0.46 [0.27-0.61] vs 0.12 [0.6-0.18] P < 0.001). Indentation decreased by a median of 20%.

CONCLUSIONS

The synergic effects of hyaluronic acid and dermo-restructuring complex show an objective amelioration of skin texture, wrinkles, and self-evaluation of skin appearance.

Engineered cell and tissue models of pulmonary fibrosis

Pulmonary fibrosis includes several lung disorders characterized by scar formation and Idiopathic Pulmonary Fibrosis (IPF) is a particularly severe form of pulmonary fibrosis of unknown etiology with a mean life expectancy of 3years' post-diagnosis. Treatments for IPF are limited to two FDA approved drugs, pirfenidone and nintedanib. Most lead candidate drugs that are identified in pre-clinical animal studies fail in human clinical trials. Thus, there is a need for advanced humanized in vitro models of the lung to improve candidate treatments prior to moving to human clinical trials. The development of 3D tissue models has created systems capable of emulating human lung structure, function, and cell and matrix interactions. The specific models accomplish these features and preliminary studies conducted using some of these systems have shown potential for in vitro anti-fibrotic drug testing. Further characterization and improvements will enable these tissue models to extend their utility for in vitro drug testing, to help identify signaling pathways and mechanisms for new drug targets, and potentially reduce animal models as standard pre-clinical models of study. In the current review, we contrast different in vitro models based on increasing dimensionality (2D, 2.5D and 3D), with added focus on contemporary 3D pulmonary models of fibrosis.

Differential Regulation of Extracellular Matrix Components Using Different Vitamin C Derivatives in Mono- and Coculture Systems

Vascular tissue engineering strategies using cell-seeded scaffolds require uniformly distributed vascular cells and sufficient extracellular matrix (ECM) production. However, acquiring sufficient ECM deposition on synthetic biomaterial scaffolds during the in vitro culture period prior to tissue implantation still remains challenging for vascular constructs. Two forms of vitamin C derivatives, ascorbic acid (AA) and sodium ascorbate (SA), are commonly supplemented in cell culture to promote ECM accumulation. However, the literature often refers to AA and SA interchangeably, and their differential effects on cell growth and ECM molecule (glycosaminoglycan, collagen, elastin) accumulation have never been reported when used in monoculture or coculture systems developed with synthetic three-dimensional (3D) scaffolds. In this study, it was found that 200 μM AA stimulated an increase in cell number, whereas SA (50, 100, and 200 μM) supported more calponin expression (immunostaining) and higher ECM accumulation from vascular smooth muscle cells (VSMCs) after 1 week in the degradable polar hydrophobic ionic polyurethane scaffold. The influence of AA and SA on ECM deposition was also studied in VSMC-monocyte cocultures to replicate some aspects of a wound healing environment in vitro and compared to their effects in respective VSMC monocultures after 4 weeks. Although 100 μM SA promoted ECM deposition in coculture, the condition of 100 μM AA + 100 μM SA was more effective toward enhancing ECM accumulation in VSMC monoculture after 4 weeks. The results demonstrated that AA and SA are not interchangeable, and the different effects of AA and/or SA on ECM deposition were both culture system (co- vs monoculture) and culture period (1 vs 4 week) dependent. This study provides further insight into practical vascular tissue engineering strategies when using 3D synthetic biomaterial-based constructs.

Longitudinal Stretching for Maturation of Vascular Tissues Using Magnetic Forces

Cellular spheroids were studied to determine their use as “bioinks” in the biofabrication of tissue engineered constructs. Specifically, magnetic forces were used to mediate the cyclic longitudinal stretching of tissues composed of Janus magnetic cellular spheroids (JMCSs), as part of a post-processing method for enhancing the deposition and mechanical properties of an extracellular matrix (ECM). The purpose was to accelerate the conventional tissue maturation process via novel post-processing techniques that accelerate the functional, structural, and mechanical mimicking of native tissues. The results of a forty-day study of JMCSs indicated an expression of collagen I, collagen IV, elastin, and fibronectin, which are important vascular ECM proteins. Most notably, the subsequent exposure of fused tissue sheets composed of JMCSs to magnetic forces did not hinder the production of these key proteins. Quantitative results demonstrate that cyclic longitudinal stretching of the tissue sheets mediated by these magnetic forces increased the Young’s modulus and induced collagen fiber alignment over a seven day period, when compared to statically conditioned controls. Specifically, the elastin and collagen content of these dynamically-conditioned sheets were 35- and three-fold greater, respectively, at seven days compared to the statically-conditioned controls at three days. These findings indicate the potential of using magnetic forces in tissue maturation, specifically through the cyclic longitudinal stretching of tissues.

Clinical effects of an oral supplement rich in antioxidants on skin radiance in women

Background

Environmental factors impact the skin aging resulting in decrease of skin radiance. Nutrition and particularly antioxidants could help to fight against skin degradation.

Objective

The aim of this study was to evaluate the effects of an oral supplement rich in specific antioxidants, SkinAx^2TM, on the improvement of the skin radiance in women.

Methods

The open-label clinical study enrolled 35 women, aged 40–70, with facial dull complexion. Subjects were supplemented orally with a daily dosage of 150 mg of an antioxidant-rich formulation containing superoxide dismutase-rich melon concentrate, grape seed extract rich in monomers of flavanols, vitamin C, and zinc for 8 weeks. Each subject served as her own control. The C.L.B.T.^™ test has been used to evaluate facial skin coloring (C), luminosity (L), brightness (B), and transparency (T) involved in skin radiance. Facial skin imperfections have been assessed by clinical assessment. Firmness has been evaluated by clinical assessment and cutometer measurement. Finally, an auto-questionnaire has been carried out in order to evaluate the satisfaction of the subjects concerning different parameters involved in skin radiance and the global efficacy of the supplement.

Results

Skin “red pink” and “olive” colors were significantly improved after supplementation (P<0.0001). Luminosity was increased by 25.9% (P<0.0001) whereas brightness and transparency were not affected by the supplementation. Facial skin imperfections were significantly reduced after the antioxidant-rich formulation intake (global reduction: −18.0%; P<0.0001). Indeed, dark circles, redness, and spots significantly diminished after oral treatment. Firmness and elasticity have been shown to be improved. Subjects were globally satisfied by the product (82.4%) and have found improvements on their facial skin. Furthermore, 64.7% reported to look better at the end of the supplementation.

Conclusion

The oral supplement containing the antioxidant-rich formulation was found to improve skin radiance by reducing skin coloring, increasing face luminosity, reducing imperfections, and improving skin firmness in women with dull complexion.