Fibrin and Marine-Derived Agaroses for the Generation of Human Bioartificial Tissues: An Ex Vivo and In Vivo Study.

Development of an ideal biomaterial for clinical use is one of the main objectives of current research in tissue engineering. Marine-origin polysaccharides, in particular agaroses, have been widely explored as scaffolds for tissue engineering. We previously developed a biomaterial based on a combination of agarose with fibrin, that was successfully translated to clinical practice. However, in search of novel biomaterials with improved physical and biological properties, we have now generated new fibrin-agarose (FA) biomaterials using 5 different types of agaroses at 4 different concentrations. First, we evaluated the cytotoxic effects and the biomechanical properties of these biomaterials. Then, each bioartificial tissue was grafted in vivo and histological, histochemical and immunohistochemical analyses were performed after 30 days. Ex vivo evaluation showed high biocompatibility and differences in their biomechanical properties. In vivo, FA tissues were biocompatible at the systemic and local levels, and histological analyses showed that biointegration was associated to a pro-regenerative process with M2-type CD206-positive macrophages. These results confirm the biocompatibility of FA biomaterials and support their clinical use for the generation of human tissues by tissue engineering, with the possibility of selecting specific agarose types and concentrations for applications requiring precise biomechanical properties and in vivo reabsorption times.

Environmental Exposure during Pregnancy: Influence on Prenatal Development and Early Life: A Comprehensive Review.

Preconception and prenatal exposure to environmental contaminants may affect future health. Pregnancy and early life are critical sensitive windows of susceptibility. The aim of this review was to summarize current evidence on the toxic effects of environment exposure during pregnancy, the neonatal period, and childhood. Alcohol use is related to foetal alcohol spectrum disorders, foetal alcohol syndrome being its most extreme form. Smoking is associated with placental abnormalities, preterm birth, stillbirth, or impaired growth and development, as well as with intellectual impairment, obesity, and cardiovascular diseases later in life. Negative birth outcomes have been linked to the use of drugs of abuse. Pregnant and lactating women are exposed to endocrine-disrupting chemicals and heavy metals present in foodstuffs, which may alter hormones in the body. Prenatal exposure to these compounds has been associated with pre-eclampsia and intrauterine growth restriction, preterm birth, and thyroid function. Metals can accumulate in the placenta, causing foetal growth restriction. Evidence on the effects of air pollutants on pregnancy is constantly growing, for example, preterm birth, foetal growth restriction, increased uterine vascular resistance, impaired placental vascularization, increased gestational diabetes, and reduced telomere length. The advantages of breastfeeding outweigh any risks from contaminants. However, it is important to assess health outcomes of toxic exposures via breastfeeding. Initial studies suggest an association between pre-eclampsia and environmental noise, particularly with early-onset pre-eclampsia. There is rising evidence of the negative effects of environmental contaminants following exposure during pregnancy and breastfeeding, which should be considered a major public health issue.

Evaluation of Marine Agarose Biomaterials for Tissue Engineering Applications.

Five agarose types (D1LE, D2LE, LM, MS8 and D5) were evaluated in tissue engineering and compared for the first time using an array of analysis methods. Acellular and cellular constructs were generated from 0.3-3%, and their biomechanical properties, in vivo biocompatibility (as determined by LIVE/DEAD, WST-1 and DNA release, with n = 6 per sample) and in vivo biocompatibility (by hematological and biochemical analyses and histology, with n = 4 animals per agarose type) were analyzed. Results revealed that the biomechanical properties of each hydrogel were related to the agarose concentration (p < 0.001). Regarding the agarose type, the highest (p < 0.001) Young modulus, stress at fracture and break load were D1LE, D2LE and D5, whereas the strain at fracture was higher in D5 and MS8 at 3% (p < 0.05). All agaroses showed high biocompatibility on human skin cells, especially in indirect contact, with a correlation with agarose concentration (p = 0.0074 for LIVE/DEAD and p = 0.0014 for WST-1) and type, although cell function tended to decrease in direct contact with highly concentrated agaroses. All agaroses were safe in vivo, with no systemic effects as determined by hematological and biochemical analysis and histology of major organs. Locally, implants were partially encapsulated and a pro-regenerative response with abundant M2-type macrophages was found. In summary, we may state that all these agarose types can be safely used in tissue engineering and that the biomechanical properties and biocompatibility were strongly associated to the agarose concentration in the hydrogel and partially associated to the agarose type. These results open the door to the generation of specific agarose-based hydrogels for definite clinical applications such as the human skin, cornea or oral mucosa.

Optimization of human skin keratinocyte culture protocols using bioactive molecules derived from olive oil.

Skin damage due to severe burns can compromise patient life. Current tissue engineering methods allow the generation of human skin substitutes for clinical use. However, this process is time-consuming, as the keratinocytes required to generate artificial skin have a low proliferation rate in culture. In this study, we evaluated the pro-proliferative effects of three natural biomolecules isolated from olive oil: phenolic extract (PE), DL-3,4-dihydroxyphenyl glycol (DHFG), and oleuropein (OLP), on cultured human skin keratinocytes. The results showed that PE and OLP increased the proliferation of immortalized human skin keratinocytes, especially at concentrations of 10 and 5 µg/mL, respectively, without altering cell viability. In contrast, DHFG did not produce a significant improvement in keratinocyte proliferation. In normal human skin keratinocytes obtained from skin biopsies, we found that PE, but not OLP, could increase the number of keratinocyte colonies and the area occupied by these cells. Furthermore, this effect was associated with increased KI-67 and Proliferating cell nuclear antigen (PCNA) gene expression. Thus, we propose that PE positively affects keratinocyte proliferation and could be used in culture protocols to improve bioartificial skin generation by tissue engineering.

Biological Effects of Maslinic Acid on Human Epithelial Cells Used in Tissue Engineering.

In the present work, we evaluated the potential of maslinic acid (MA) to improve currently available keratinocyte culture methods for use in skin tissue engineering. Results showed that MA can increase cell proliferation and WST-1 activity of human keratinocytes after 24, 48, and 72 h, especially at the concentration of 5 µg/ml, without affecting cell viability. This effect was associated to a significant increase of KI-67 protein expression and upregulation of several genes associated to cell proliferation (PCNA) and differentiation (cytokeratins, intercellular junctions and basement membrane related genes). When human keratinocytes were isolated from skin biopsies, we found that MA at the concentration of 5 µg/ml significantly increased the efficiency of the explant and the cell dissociation methods. These results revealed the positive effects of MA to optimize human keratinocyte culture protocols for use in skin tissue engineering.

Generation and Evaluation of Novel Biomaterials Based on Decellularized Sturgeon Cartilage for Use in Tissue Engineering.

Because cartilage has limited regenerative capability, a fully efficient advanced therapy medicinal product is needed to treat severe cartilage damage. We evaluated a novel biomaterial obtained by decellularizing sturgeon chondral endoskeleton tissue for use in cartilage tissue engineering. In silico analysis suggested high homology between human and sturgeon collagen proteins, and ultra-performance liquid chromatography confirmed that both types of cartilage consisted mainly of the same amino acids. Decellularized sturgeon cartilage was recellularized with human chondrocytes and four types of human mesenchymal stem cells (MSC) and their suitability for generating a cartilage substitute was assessed ex vivo and in vivo. The results supported the biocompatibility of the novel scaffold, as well as its ability to sustain cell adhesion, proliferation and differentiation. In vivo assays showed that the MSC cells in grafted cartilage disks were biosynthetically active and able to remodel the extracellular matrix of cartilage substitutes, with the production of type II collagen and other relevant components, especially when adipose tissue MSC were used. In addition, these cartilage substitutes triggered a pro-regenerative reaction mediated by CD206-positive M2 macrophages. These preliminary results warrant further research to characterize in greater detail the potential clinical translation of these novel cartilage substitutes.

Study of the fetal and maternal microbiota in pregnant women with intrauterine growth restriction and its relationship with inflammatory biomarkers: A case-control study protocol (SPIRIT compliant).

In general terms, fetal growth restriction (FGR) is considered the impossibility of achieving the genetically determined potential size. In the vast majority of cases, it is related to uteroplacental insufficiency. Although its origin remains unknown and causes are only known in 30% of cases, it is believed to be related to an interaction of environmental and genetic factors with either a fetal or maternal origin. One hypothesis is that alterations in the gastrointestinal microbiota composition, and thus alteration in the immune response, could play a role in FGR development. We performed an observational, prospective study in a subpopulation affected with FGR to elucidate the implications of this microbiota on the FGR condition.A total of 63 fetuses with FGR diagnosed in the third trimester as defined by the Delphi consensus, and 63 fetuses with fetal growth appropriate for gestational age will be recruited. Obstetric and nutritional information will be registered by means of specific questionnaires. We will collect maternal fecal samples between 30 to 36 weeks, intrapartum samples (maternal feces, maternal and cord blood) and postpartum samples (meconium and new-born feces at 6 weeks of life). Samples will be analyzed in the Department of Biochemistry and Molecular Biology II, Nutrition and Food Technology Institute of the University of Granada (UGR), for the determination of the gastrointestinal microbiota composition and its relationship with inflammatory biomarkers.This study will contribute to a better understanding of the influence of gastrointestinal microbiota and related inflammatory biomarkers in the development of FGR.Trial registration: NCT04047966. Registered August 7, 2019, during the recruitment stage. Retrospectively registered. Ongoing research.