Iron Metabolism, Calcium, Magnesium and Trace Elements: A Review.

Iron (Fe) is fundamental to life on earth. In the human body, it is both essential and harmful if above threshold. A similar balance applies to other elements: calcium (Ca), magnesium (Mg), and trace elements including copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), mercury (Hg), and nickel (Ni). These elements share some proteins involved in the absorption and transport of Fe. Cu and Cd can inhibit Fe absorption, while excess of Fe may antagonize Cu metabolism and reduce ceruloplasmin (Cp). Excessive Fe can hinder Zn absorption and transferrin (Trf) can bind to both Zn and Ni. Ca is able to inhibit the divalent metal transporter 1 (DMT1) in a dose-dependent manner to reduce Fe absorption and low Mg concentrations can exacerbate Fe deficiency. Pb competitively inhibits Fe distribution and elevated Cd absorption reduces Fe uptake. Exposure to Hg is associated with higher ferritin concentrations and Ni alters intracellular Fe metabolism. Fe removal by phlebotomy in hemochromatosis patients has shown to increase the levels of Cd and Pb and alter the concentrations of trace elements in some types of anemia. Yet, the effects of chronic exposure of most trace elements remain poorly understood.

Response of human oral mucosal epithelial cells to different storage temperatures: A structural and transcriptional study.

PURPOSE: Seeking to improve the access to regenerative medicine, this study investigated the structural and transcriptional effects of storage temperature on human oral mucosal epithelial cells (OMECs). METHODS: Cells were stored at four different temperatures (4°C, 12°C, 24°C and 37°C) for two weeks. Then, the morphology, cell viability and differential gene expression were examined using light and scanning electron microscopy, trypan blue exclusion test and TaqMan gene expression array cards, respectively. RESULTS: Cells stored at 4°C had the most similar morphology to non-stored controls with the highest viability rate (58%), whereas the 37°C group was most dissimilar with no living cells. The genes involved in stress-induced growth arrest (GADD45B) and cell proliferation inhibition (TGFB2) were upregulated at 12°C and 24°C. Upregulation was also observed in multifunctional genes responsible for morphology, growth, adhesion and motility such as EFEMP1 (12°C) and EPHA4 (4°C-24°C). Among genes used as differentiation markers, PPARA and TP53 (along with its associated gene CDKN1A) were downregulated in all temperature conditions, whereas KRT1 and KRT10 were either unchanged (4°C) or downregulated (24°C and 12°C; and 24°C, respectively), except for upregulation at 12°C for KRT1. CONCLUSIONS: Cells stored at 12°C and 24°C were stressed, although the expression levels of some adhesion-, growth- and apoptosis-related genes were favourable. Collectively, this study suggests that 4°C is the optimal storage temperature for maintenance of structure, viability and function of OMECs after two weeks.

Intense pulsed light treatment in meibomian gland dysfunction: A concise review.

PURPOSE: To review the published literature related to application of intense pulsed light (IPL) for treating meibomian gland dysfunction (MGD). METHODS: The literature search included the PubMed database and used the keywords "Intense Pulsed Light and Meibomian Gland Dysfunction". RESULTS: IPL is a new instrumental treatment modality for MGD. This treatment modality was originally developed for use in dermatology and was later adopted in ophthalmology for treating MGD. IPL therapy for MGD can improve tear film stability, meibomian gland functionality, as well as subjective feeling of ocular dryness. However, in the reviewed literature, there was great variability in patient selection, evaluation criteria, and treatment protocols and durations. CONCLUSION: Numerous studies report that IPL is effective for treating MGD and a safe procedure. There is great potential for further improvements to the procedure, as large comparative studies employing different treatment modalities are lacking.

Distinct Subsets of Noncoding RNAs Are Strongly Associated With BMD and Fracture, Studied in Weight-Bearing and Non-Weight-Bearing Human Bone.

We investigated mechanisms resulting in low bone mineral density (BMD) and susceptibility to fracture by comparing noncoding RNAs (ncRNAs) in biopsies of non-weight-bearing (NWB) iliac (n = 84) and weight bearing (WB) femoral (n = 18) postmenopausal bone across BMDs varying from normal (T-score > -1.0) to osteoporotic (T-score ≤ -2.5). Global bone ncRNA concentrations were determined by PCR and microchip analyses. Association with BMD or fracture, adjusted by age and body mass index, were calculated using linear and logistic regression and least absolute shrinkage and selection operator (Lasso) analysis. At 10% false discovery rate (FDR), 75 iliac bone ncRNAs and 94 femoral bone ncRNAs were associated with total hip BMD. Eight of the ncRNAs were common for the two sites, but five of them (miR-484, miR-328-3p, miR-27a-5p, miR-28-3p, and miR-409-3p) correlated positively to BMD in femoral bone, but negatively in iliac bone. Of predicted pathways recognized in bone metabolism, ECM-receptor interaction and proteoglycans in cancer emerged at both sites, whereas fatty acid metabolism and focal adhesion were only identified in iliac bone. Lasso analysis and cross-validations identified sets of nine bone ncRNAs correlating strongly with adjusted total hip BMD in both femoral and iliac bone. Twenty-eight iliac ncRNAs were associated with risk of fracture (FDR < 0.1). The small nucleolar RNAs, RNU44 and RNU48, have a function in stabilization of ribosomal RNAs (rRNAs), and their association with fracture and BMD suggest that aberrant processing of rRNAs may be involved in development of osteoporosis. Cis-eQTL (expressed quantitative trait loci) analysis of the iliac bone biopsies identified two loci associated with microRNAs (miRNAs), one previously identified in a heel-BMD genomewide association study (GWAS). In this comprehensive investigation of the skeletal genetic background in postmenopausal women, we identified functional bone ncRNAs associated to fracture and BMD, representing distinct subsets in WB and NWB skeletal sites. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

A Hyaluronan Hydrogel Scaffold for Culture of Human Oral Mucosal Epithelial Cells in Limbal Stem-Cell Therapy.

Hyaluronan (HA), a major component of the extracellular matrix, plays a key role in cell proliferation, growth, survival, polarization and differentiation. We investigated the optimization of a HA hydrogel scaffold for culture of human oral mucosal epithelial cells (OMECs) for potential application in limbal stem cell therapy. The effect of the optimized scaffold on OMEC cell sheet morphology, cell metabolic activity and expression of genes associated with stemness, adherence and cell damage was studied. The results indicate that HA hydrogels crosslinked with polyethylene glycol diacrylate (PEGDA) failed to support OMEC attachment and growth. However, HA hydrogel scaffolds dried for three days and coated with 1 mg/mL collagen IV produced a full OMEC sheet. Cell morphology was comparable to control after three weeks culture, maintaining 76% metabolic activity. Of apoptosis-related genes, the pro-apoptotic markers CASP3 and BAX2 were upregulated and downregulated, respectively, compared to control whereas the anti-apoptotic marker BCL2 was downregulated. The expression level of stemness genes ΔNp63α and ABCG2 was significantly higher than control. Genes associated with improved scar-less wound healing (integrin-V) and protection of the ocular surface (cadherin-1) had ~3-fold increased expression. These data suggest that our optimized HA-hydrogel scaffold could enhance culture of OMEC cell sheets for use in ocular reconstruction.

Hyaluronan-Based Hydrogel Scaffolds for Limbal Stem Cell Transplantation: A Review.

Hyaluronan (HA), also termed hyaluronic acid or hyaluronate, is a major component of the extracellular matrix. This non-sulfated glycosaminoglycan plays a key role in cell proliferation, growth, survival, polarization, and differentiation. The diverse biological roles of HA are linked to the combination of HA's physicochemical properties and HA-binding proteins. These unique characteristics have encouraged the application of HA-based hydrogel scaffolds for stem cell-based therapy, a successful method in the treatment of limbal stem cell deficiency (LSCD). This condition occurs following direct damage to limbal stem cells and/or changes in the limbal stem cell niche microenvironment due to intrinsic and extrinsic insults. This paper reviews the physical properties, synthesis, and degradation of HA. In addition, the interaction of HA with other extracellular matrix (ECM) components and receptor proteins are discussed. Finally, studies employing HA-based hydrogel scaffolds in the treatment of LSCD are reviewed.

Fibrous shape underlies the mutagenic and carcinogenic potential of nanosilver while surface chemistry affects the biosafety of iron oxide nanoparticles.

Nowadays engineered nanomaterials (ENMs) are increasingly used in a wide range of commercial products and biomedical applications. Despite this, the knowledge of human potential health risk as well as comprehensive biological and toxicological information is still limited. We have investigated the capacity of two frequently used metallic ENMs, nanosilver and magnetite nanoparticles (MNPs), to induce thymidine kinase (Tk +/-) mutations in L5178Y mouse lymphoma cells and transformed foci in Bhas 42 cells. Two types of nanosilver, spherical nanoparticles (AgNM300) and fibrous (AgNM302) nanorods/wires, and MNPs differing in surface modifications [MNPs coated with sodium oleate (SO-MNPs), MNPs coated with SO + polyethylene glycol (SO-PEG-MNPs) and MNPs coated with SO + PEG + poly(lactide-co-glycolic acid) SO-PEG-PLGA-MNPs] were included in this study. Spherical AgNM300 showed neither mutagenic nor carcinogenic potential. In contrast, silver nanorods/wires (AgNM302) increased significantly the number of both gene mutations and transformed foci compared with the control (untreated) cells. Under the same treatment conditions, neither SO-MNPs nor SO-PEG-PLGA-MNPs increased the mutant frequency compared with control cells though an equivocal mutagenic effect was estimated for SO-PEG-MNPs. Although SO-MNPs and SO-PEG-MNPs did not show any carcinogenic potential, SO-PEG-PLGA-MNPs increased concentration dependently the number of transformed foci in Bhas 42 cells compared with the control cells. Our results revealed that fibrous shape underlies the mutagenic and carcinogenic potential of nanosilver while surface chemistry affects the biosafety of MNPs. Considering that both nanosilver and MNPs are prospective ENMs for biomedical applications, further toxicological evaluations are warranted to assess comprehensively the biosafety of these nanomaterials.

A Kinetic Study of Reactive Oxygen Species in Rainbow Trout Hepatocytes by Fluorometry.

The kinetics of reactive oxygen species (ROS) formation in a primary culture of rainbow trout hepatocytes was investigated using three fluorescent probes: 5-,6-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H2DCFDA), dihydrorhodamine 123 (DHR 123), and dihydroethidium (DHE). The cell cultures were loaded with the three probes, separately. Hepatocytes were then exposed to Cu (0.15-10 mM) in serum-free Leibovitz's medium for 30 min before being quantified by a fluorescence plate reader during 30 min. Membrane integrity and glutathione (GSH) content were quantified using the fluorescent probes 5-carboxyfluorescein diacetate-acetoxymethyl ester (CFDA-AM) and monochlorobimane. Increasing ROS formation with increasing concentrations of Cu was shown using CM-H2DCFDA, whereas DHR 123 fluorescence decreased. Significant differences between control and treatment groups were observed at the highest concentrations (2.5 and 10 mM) for both probes. DHE fluorescence was lower than that of the other two probes and did not appear to be affected by any exposure. Additionally, a dose-dependent depletion of GSH and decreasing membrane integrity with increasing Cu concentrations were demonstrated, with significant effects observed at 2.5 and 10 mM for both endpoints. The results showed that both CMH2DCFDA and DHR 123 detected the development of their target Cu-induced ROS in trout hepatocytes but did so in opposite fashions. DHE was found to be unsuitable for detecting kinetics of ROS formation in this model system.