Changes in the levels of free sialic acid during ex vivo lung perfusion do not correlate with pulmonary function. Experimental model.

BACKGROUND: Ex vivo lung perfusion (EVLP) constitutes a tool with great research potential due to its advantages over in vivo and in vitro models. Despite its important contribution to lung reconditioning, this technique has the disadvantage of incurring high costs and can induce pulmonary endothelial injury through perfusion and ventilation. The pulmonary endothelium is made up of endothelial glycocalyx (EG), a coating of proteoglycans (PG) on the luminal surface. PGs are glycoproteins linked to terminal sialic acids (Sia) that can affect homeostasis with responses leading to edema formation. This study evaluated the effect of two ex vivo perfusion solutions on lung function and endothelial injury. METHODS: We divided ten landrace swine into two groups and subjected them to EVLP for 120 min: Group I (n = 5) was perfused with Steen® solution, and Group II (n = 5) was perfused with low-potassium dextran-albumin solution. Ventilatory mechanics, histology, gravimetry, and sialic acid concentrations were evaluated. RESULTS: Both groups showed changes in pulmonary vascular resistance and ventilatory mechanics (p < 0.05, Student's t-test). In addition, the lung injury severity score was better in Group I than in Group II (p < 0.05, Mann-Whitney U); and both groups exhibited a significant increase in Sia concentrations in the perfusate (p < 0.05 t-Student) and Sia immunohistochemical expression. CONCLUSIONS: Sia, as a product of EG disruption during EVLP, was found in all samples obtained in the system; however, the changes in its concentration showed no apparent correlation with lung function.

Pluripotent Stem Cells as a Model for Human Embryogenesis.

Pluripotent stem cells (PSCs; embryonic stem cells and induced pluripotent stem cells) can recapitulate critical aspects of the early stages of embryonic development; therefore, they became a powerful tool for the in vitro study of molecular mechanisms that underlie blastocyst formation, implantation, the spectrum of pluripotency and the beginning of gastrulation, among other processes. Traditionally, PSCs were studied in 2D cultures or monolayers, without considering the spatial organization of a developing embryo. However, recent research demonstrated that PSCs can form 3D structures that simulate the blastocyst and gastrula stages and other events, such as amniotic cavity formation or somitogenesis. This breakthrough provides an unparalleled opportunity to study human embryogenesis by examining the interactions, cytoarchitecture and spatial organization among multiple cell lineages, which have long remained a mystery due to the limitations of studying in utero human embryos. In this review, we will provide an overview of how experimental embryology currently utilizes models such as blastoids, gastruloids and other 3D aggregates derived from PSCs to advance our understanding of the intricate processes involved in human embryo development.

Recent advances in the use of CRISPR/Cas for understanding the early development of molecular gaps in glial cells.

Glial cells are non-neuronal elements of the nervous system (NS) and play a central role in its development, maturation, and homeostasis. Glial cell interest has increased, leading to the discovery of novel study fields. The CRISPR/Cas system has been widely employed for NS understanding. Its use to study glial cells gives crucial information about their mechanisms and role in the central nervous system (CNS) and neurodegenerative disorders. Furthermore, the increasingly accelerated discovery of genes associated with the multiple implications of glial cells could be studied and complemented with the novel screening methods of high-content and single-cell screens at the genome-scale as Perturb-Seq, CRISP-seq, and CROPseq. Besides, the emerging methods, GESTALT, and LINNAEUS, employed to generate large-scale cell lineage maps have yielded invaluable information about processes involved in neurogenesis. These advances offer new therapeutic approaches to finding critical unanswered questions about glial cells and their fundamental role in the nervous system. Furthermore, they help to better understanding the significance of glial cells and their role in developmental biology.

The human amniotic epithelium confers a bias to differentiate toward the neuroectoderm lineage in human embryonic stem cells.

Human embryonic stem cells (hESCs) derive from the epiblast and have pluripotent potential. To maintain the conventional conditions of the pluripotent potential in an undifferentiated state, inactivated mouse embryonic fibroblast (iMEF) is used as a feeder layer. However, it has been suggested that hESC under this conventional condition (hESC-iMEF) is an artifact that does not correspond to the in vitro counterpart of the human epiblast. Our previous studies demonstrated the use of an alternative feeder layer of human amniotic epithelial cells (hAECs) to derive and maintain hESC. We wondered if the hESC-hAEC culture could represent a different pluripotent stage than that of naïve or primed conventional conditions, simulating the stage in which the amniotic epithelium derives from the epiblast during peri-implantation. Like the conventional primed hESC-iMEF, hESC-hAEC has the same levels of expression as the 'pluripotency core' and does not express markers of naïve pluripotency. However, it presents a downregulation of HOX genes and genes associated with the endoderm and mesoderm, and it exhibits an increase in the expression of ectoderm lineage genes, specifically in the anterior neuroectoderm. Transcriptome analysis showed in hESC-hAEC an upregulated signature of genes coding for transcription factors involved in neural induction and forebrain development, and the ability to differentiate into a neural lineage was superior in comparison with conventional hESC-iMEF. We propose that the interaction of hESC with hAEC confers hESC a biased potential that resembles the anteriorized epiblast, which is predisposed to form the neural ectoderm.

Endothelin-Converting Enzyme 1 and Vascular Endothelial Growth Factor as Potential Biomarkers during Ex Vivo Lung Perfusion with Prolonged Hypothermic Lung-Sparing.

Lung transplantation requires optimization of donor's organ use through ex vivo lung perfusion (EVLP) to avoid primary graft dysfunction. Biomarkers can aid in organ selection by providing early evidence of suboptimal lungs during EVLP and thus avoid high-risk transplantations. However, predictive biomarkers of pulmonary graft function such as endothelin-converting enzyme (ECE-1) and vascular endothelial growth factor (VEGF) have not been described under EVLP with standard prolonged hypothermic preservation, which are relevant in situations where lung procurement is difficult or far from the transplantation site. Therefore, this study is aimed at quantifying ECE-1 and VEGF, as well as determining their association with hemodynamic, gasometric, and mechanical ventilatory parameters in a swine model of EVLP with standard prolonged hypothermic preservation. Using a protocol with either immediate (I-) or delayed (D-) initiation of EVLP, ECE-1 levels over time were found to remain constant in both study groups (p > 0.05 RM-ANOVA), while the VEGF protein was higher after prolonged preservation, but it decreased throughout EVLP (p > 0.05 RM-ANOVA). Likewise, hemodynamic, gasometric, mechanical ventilatory, and histological parameters had a tendency to better results after 12 hours of hypothermic preservation in the delayed infusion group.

Prolactin from Pluripotency to Central Nervous System Development.

Prolactin (PRL) is a versatile hormone that exerts more than 300 functions in vertebrates, mainly associated with physiological effects in adult animals. Although the process that regulates early development is poorly understood, evidence suggests a role of PRL in the early embryonic development regarding pluripotency and nervous system development. Thus, PRL could be a crucial regulator in oocyte preimplantation and maturation as well as during diapause, a reversible state of blastocyst development arrest that shares metabolic, transcriptomic, and proteomic similarities with pluripotent stem cells in the naïve state. Thus, we analyzed the role of the hormone during those processes, which involve the regulation of its receptor and several signaling cascades (Jak/Mapk, Jak/Stat, and PI3k/Akt), resulting in either a plethora of physiological actions or their dysregulation, a factor in developmental disorders. Finally, we propose models to improve the knowledge on PRL function during early development.

Improvement of the wound healing properties of hydrogels with N-acetylcysteine through their modification with methacrylate-containing polymers.

Hydrogels with antioxidant activity have shown to significantly improve the standard of care, because they promote efficient wound healing, i.e. regeneration. N-Acetylcysteine (NAC) is an antioxidant amino acid derivative that promotes complete tissue restoration. However, NAC has anticoagulant properties that may also hinder blood coagulation, which is crucial for hydrogels for wound healing applications. To take advantage of the regenerative activity of NAC while avoiding hampering the hemostasis stage during wound healing, we modified gelatin-NAC with the methacrylate-containing polymers 2-hydroxyethyl methacrylate (H) and poly(ethylene glycol) methyl ether methacrylate (P) to produce Gel-HP-NAC. These hydrogels clotted more blood and faster than Gel and Gel-NAC hydrogels, while maintaining fluid absorption properties adequate to promote wound healing. Similarly, there were more viable human skin fibroblasts after 10 days cultured in Gel-HP-NAC compared with Gel and Gel-NAC. A mouse full-thickness skin wound model demonstrated that Gel-HP-NAC hydrogels improved the wound healing process as compared to the untreated group as proved by the increased wound closure rates and re-epithelialization. Histology of the biopsied tissues indicated more organized collagen deposits on the wounds treated with either Gel-HP-NAC or Gel-NAC than untreated wounds. Our results show that modification of NAC-containing hydrogels through methacrylate-containing polymers improved their wound healing properties, including blood-clotting, and demonstrate the potential of Gel-HP-NAC hydrogels for wound treatment and tissue regeneration.

Gastroprotective activity and pharmacological safety evaluation of Eupatorium aschenbornianum.

Eupatorium aschenbornianum has been widely used in traditional Mexican and folk medicine for the treatment of wounds, skin lesions, hemorrhages and gastric ulcers in humans. Phytochemical studies have indicated that hexane extracts of E. aschenbornianum have anti-microbial and anti-fungal activities. In the present study, an accurate and reliable approach using a murine model was pursued to evaluate the anti-ulcer activity, lipid peroxidation properties and acute toxicity of powdered dried stem of E. aschenbornianum. The results indicated that administration of E. aschenbornianum exerted an anti-ulcerative effect and decreased lipid peroxidation in gastric ulcers induced by acetylsalicylic acid. An acute toxicity assay indicated normal behavior and no significant variations in the weight and food consumption of animals. In addition, quantitative analysis of biochemical parameters did not indicate any liver or kidney damage. The results indicated that E. aschenbornianum may be a safe therapeutic agent for the prevention of gastric ulcers.

Establishment of human embryonic stem cell line Amicqui-2 using poor-quality embryos from Mexican population.

Although investigation with human embryonic stem cells (HESC) is not decreasing, the derivation of new lines has been diminished. The preeminence of only a few HESC lines in research is accompanied by lack of universal applicability of results as well as by genetic under-representation. We previously reported the derivation of one line with male karyotype from Mexican population. Here, we derived one HESC line (Amicqui-2) with female karyotype from poor-quality embryos. These line comply the pluripotent requirements (normal karyotype, detection of pluripotency-associated markers, mycoplasma test and teratoma formation) and could be a valuable model for studying diseases specific to under-represented population.

Pluripotency markers in tissue and cultivated cells in vitro of different regions of human amniotic epithelium.

Studies have described the presence of pluripotent markers in vivo and in vitro in human amnion. However, the amnion can be divided into reflected, placental and umbilical regions that are anatomically and functionally heterogeneous. Here, we evaluated the expression of pluripotency markers in tissue and cultivated cells in vitro of different regions of human amnion. To this end, we determined the presence of the core pluripotency factors OCT-4, NANOG and SOX-2 by immunofluorescence and RT-PCR and also performed transcriptome analysis of the different regions of amnion tissue. We identified the mRNA and protein of the pluripotency factors in the different regions of human amnion tissue. However, the OCT-4 and NANOG immunolocalization was cytoplasmic, whereas SOX-2 immunolocalization was nuclear regardless of the region analyzed. Moreover, we found three subpopulations of cells in the in vitro cultures of reflected and placental amnion: cells with immunostaining only in the nucleus, only in the cytoplasm, or in both compartments. Yet no statistically significant differences were found between the reflected and placental amnion. These results suggest a homogeneous distribution of the pluripotency transcription factors of the different regions of human amnion to isolate stem cells that can be used in regenerative medicine.

In vitro and In vivo Postprandial Glycemic Activity of Citrus limetta Peel Flour.

BACKGROUND: Previous studies of Citrus spp. peel have shown hypoglycemic and antioxidant activities. Citrus limetta has been studied for its therapeutic properties. Diabetes mellitus (DM) is a health problem in Mexico and worldwide, that takes a vital importance due to its high incidence. Recently, scientists have searched natural sources to control the disease. MATERIALS AND METHODS: In this study, we evaluated the in vitro hypoglycemic activity and in vivo postprandial glycemic effect of C. limetta peel flour by glucose adsorption and retardation assays as well as postprandial serum glucose levels using a group of female Balb-c mice, respectively. RESULTS: C. limetta peel flour showed a glucose adsorption capacity of 16.58 mM, having a similar effect regarding the positive control. The glucose diffusion in the dialysate was elevated, with a glucose dialysis retardation index of 33.79% in a period of 3 h, showing similar results to positive control. Postprandial serum glucose levels in the animal group treated with C. limetta peel flour showed a glucose level of 41.4 mg/dL, being this value significantly lower than negative control group and similar to positive control. Toxicity tests showed good tolerance to the dose of 2000 mg/kg. CONCLUSION: C. limetta peel flour could act as a source of functional compounds for the control of DM. SUMMARY: Citrus limetta peel flour showed a glucose adsorption capacity similar to the positive controlThe glucose diffusion in the dialysate was elevated, showing similar results to positive controlPostprandial serum glucose levels in the animal group treated with C. limetta peel flour showed a glucose level significantly lower than negative control group and similar to positive controlToxicity tests showed good toleranceC. limetta peel flour could act as a source of functional compounds for the control of diabetes mellitus. Abbreviations used: CIATEJ: Center for Research and Assistance in Technology and Design of Jalisco; DM: Diabetes mellitus; FGC: Final glucose concentration; GDRI: Glucose dialysis retardation index; IGC: Initial glucose concentration; OECD: Organization for Economic Cooperation and Development.

Human amniotic epithelial cells as feeder layer to derive and maintain human embryonic stem cells from poor-quality embryos.

Data from the literature suggest that human embryonic stem cell (hESC) lines used in research do not genetically represent all human populations. The derivation of hESC through conventional methods involve the destruction of viable human embryos, as well the use of mouse embryonic fibroblasts as a feeder layer, which has several drawbacks. We obtained the hESC line (Amicqui-1) from poor-quality (PQ) embryos derived and maintained on human amniotic epithelial cells (hAEC). This line displays a battery of markers of pluripotency and we demonstrated the capacity of these cells to produce derivates of the three germ layers.

[Axonal growth inhibition by chondroitin sulfate proteoglycans in the central nervous system]. / Inhibición del crecimiento axonal por proteoglicanos de condroitin sulfato en el sistema nervioso central.

Chondroitin sulphate proteoglycans (CSPG) are components of the extracellular matrix, consisting of peptides chemically attached covalently to chains of glycosaminoglycans. There are 4 families of CSPG including lecticans, which are found mainly in the central nervous system (CNS) of vertebrates. In vitro studies have shown a negative effect of these proteoglycans on axonal growth, mediated by depolymerization of actin filaments in the neuronal cytoskeleton. In some neurodegenerative diseases, and especially after traumatic injuries of adult CNS, there are increased levels of CSPG expression. Axonal growth inhibition by CSPG has been observed also in vivo, and therefore a strategy aimed to counteract the inhibition of axonal growth might lead to new therapies designed to restore neural circuits. There is compelling in vivo evidence that CSPG degradation by Chondroitinase ABC allows both axonal growth and functional recovery in models of injury in the mammalian CNS. These data suggest that manipulation of the response to damage could result in effective ways to promote recovery of nerve functions in neurological disorders that affect humans, such as spinal cord lesions or Parkinson disease.