Mechanisms of Phototoxic Effects of Cationic Porphyrins on Human Cells In Vitro.

The toxic effects of four cationic porphyrins on various human cells were studied in vitro. It was found that, under dark conditions, porphyrins are almost nontoxic, while, under the action of light, the toxic effect was observed starting from nanomolar concentrations. At a concentration of 100 nM, porphyrins caused inhibition of metabolism in the MTT test in normal and cancer cells. Furthermore, low concentrations of porphyrins inhibited colony formation. The toxic effect was nonlinear; with increasing concentrations of various porphyrins, up to about 1 µM, the effect reached a plateau. In addition to the MTT test, this was repeated in experiments examining cell permeability to trypan blue, as well as survival after 24 h. The first visible manifestation of the toxic action of porphyrins is blebbing and swelling of cells. Against the background of this process, permeability to porphyrins and trypan blue appears. Subsequently, most cells (even mitotic cells) freeze in this swollen state for a long time (24 and even 48 h), remaining attached. Cellular morphology is mostly preserved. Thus, it is clear that the cells undergo mainly necrotic death. The hypothesis proposed is that the concentration dependence of membrane damage indicates a limited number of porphyrin targets on the membrane. These targets may be any ion channels, which should be considered in photodynamic therapy.

Characterizing and Quenching Autofluorescence in Fixed Mouse Adrenal Cortex Tissue.

Tissue autofluorescence of fixed tissue sections is a major concern of fluorescence microscopy. The adrenal cortex emits intense intrinsic fluorescence that interferes with signals from fluorescent labels, resulting in poor-quality images and complicating data analysis. We used confocal scanning laser microscopy imaging and lambda scanning to characterize the mouse adrenal cortex autofluorescence. We evaluated the efficacy of tissue treatment methods in reducing the intensity of the observed autofluorescence, such as trypan blue, copper sulfate, ammonia/ethanol, Sudan Black B, TrueVIEWTM Autofluorescence Quenching Kit, MaxBlockTM Autofluorescence Reducing Reagent Kit, and TrueBlackTM Lipofuscin Autofluorescence Quencher. Quantitative analysis demonstrated autofluorescence reduction by 12-95%, depending on the tissue treatment method and excitation wavelength. TrueBlackTM Lipofuscin Autofluorescence Quencher and MaxBlockTM Autofluorescence Reducing Reagent Kit were the most effective treatments, reducing the autofluorescence intensity by 89-93% and 90-95%, respectively. The treatment with TrueBlackTM Lipofuscin Autofluorescence Quencher preserved the specific fluorescence signals and tissue integrity, allowing reliable detection of fluorescent labels in the adrenal cortex tissue. This study demonstrates a feasible, easy-to-perform, and cost-effective method to quench tissue autofluorescence and improve the signal-to-noise ratio in adrenal tissue sections for fluorescence microscopy.

In situ transduction of cells in human corneal limbus using adeno-associated viruses: an ex vivo study.

This study aimed to evaluate the efficacy of in situ adeno-associated virus (AAV)-mediated gene delivery into the human corneal limbal region via targeted sub-limbal injection technique. Human cadaveric corneal tissues were fixed on an artificial anterior chamber. Feasibility of sub-limbal injection technique was tested using trypan blue and black India ink. An enhanced green fluorescent protein (eGFP) encoding AAV DJ was injected into sub-limbal region. After AAV injection, corneal tissues were incubated in air-lift culture and prepared for immunohistochemical analysis. Cell survivial and expression of eGFP, stem cell markers (p63α and cytokeratin 19 (KRT19)), and differentiation marker cytokeratin 3 (KRT3) were evaluated using confocal microscopy. Both trypan blue and black India ink stained and were retained sub-limbally establishing specificity of the injection technique. Immunohistochemical analysis of corneas injected with AAV DJ-eGFP indicated that AAV-transduced cells in the limbal region co-express eGFP, p63α, and KRT19 and that these transduced cells were capable of differentiating to KRT3 postitive corneal epithelial cells. Our sub-limbal injection technique can target cells in the human limbus in a reproducible and efficient manner. Thus, we demonstrate that in situ injection of corneal limbus may provide a feasible mode of genetic therapy for corneal disorders with an epithelial etiology.

Simple Staining of Cells on a Chip.

Simple staining of cells is a widely used method in basic medical diagnostics, education, and research laboratories. The stains are low-cost, but the extensive consumption results in excessive toxic waste generation. Thus, to decrease the amount of toxic waste resulting from the cell staining procedure is a need. In this study, we developed a magnetically driven and compartmentalized passive microfluidic chip to perform simple staining of human eukaryotic cells, K562 cells, and lymphocyte cells derived from patients. We demonstrated simple staining on cells with trypan blue, methylene blue, crystal violet, and safranin for high, medium, and low cell densities. The stained cells were imaged using a bright field optical microscope and a cell phone to count cells on the focal plane. The staining improved the color signal of the cell by 25-135-pixel intensity changes for the microscopic images. The validity of the protocol was determined using Jurkat and MDA-MB-231 cell lines as negative controls. In order to demonstrate the practicality of the system, lymphocyte cells derived from human blood samples were stained with trypan blue. The color intensity changes in the first and last compartments were analyzed to evaluate the performance of the chip. The developed method is ultra-low cost, significantly reduces the waste generated, and can be integrated with mobile imaging devices in terms of portability. By combining microfabrication technology with cell staining, this study reported a novel contribution to the field of microfluidic biosensors. In the future, we expect to demonstrate the detection of pathogens using this method.

Low-Dose X-Ray Increases Paracellular Permeability of Human Renal Glomerular Endothelial Cells.

Objective: Glomerular endothelium functions as a filtration barrier of metabolites in the kidney. Although X-ray irradiation modulated the permeability of the vascular endothelium, the response of human renal glomerular endothelial cells (HRGECs) to low-dose X-ray irradiation has not been investigated. We evaluated the impacts of low-dose X-ray irradiation on HRGECs and revealed the underlying mechanism. Methods: HRGECs were exposed to X-ray with doses of 0, 0.1, 0.5, 1.0, and 2.0 Gy. The proliferation, viability, and apoptosis of HRGECs were examined by MTT assay, trypan blue staining assay, and TUNEL staining, respectively. The paracellular permeability was assessed by paracellular permeability assay. The expression of VE-cadherin was investigated via immunofluorescence assay. Western blot and qRT-PCR detected the expression levels of VE-cadherin and CLDN5. Besides, the expression levels of pVE-cadherin (pY658), TGF-ß, TGF-ßRI, Src, p-Src, Smad2, p-Smad2, Smad3, p-Smad3, SNAIL, SLUG, and apoptosis-related proteins were tested by Western blot. Results: The proliferation, viability, and apoptosis of HRGECs were not affected by low-dose (<2.0 Gy) X-ray irradiation. X-ray irradiation dose-dependently reduced the level of VE-cadherin, and VE-cadherin and CLDN5 levels were reduced with X-ray irradiation. The levels of pY658, p-Src, p-Smad2, and p-Smad3 were upregulated with the increase in X-ray dose. Besides, the paracellular permeability of HRGECs was increased by even low-dose (<2.0 Gy) X-ray irradiation. Therefore, low-dose X-ray irradiation reduced the cumulative content of VE-cadherin and increased the level of pY658 via activation of the TGF-ß signaling pathway. Conclusion: Even though low-dose X-ray exposure had no impact on proliferation, viability, and apoptosis of HRGECs, it increased the paracellular permeability by deterioration and downregulation of VE-cadherin through stimulating the TGF-ß signaling pathway. This study built the framework for kidney response to low-dose irradiation exposure.

Selecting Multitarget Peptides for Alzheimer's Disease.

Alzheimer's disease (AD) is a multifactorial disease with a complex pathogenesis. Developing multitarget drugs could be a powerful strategy to impact the progressive loss of cognitive functions in this disease. The purpose of this study is to select a multitarget lead peptide candidate among a series of peptide variants derived from the neutrophil granule protein cathepsin G. We screened eight peptide candidates using the following criteria: (1) Inhibition and reversion of amyloid beta (Aß) oligomers, quantified using an enzyme-linked immunosorbent assay (ELISA); (2) direct binding of peptide candidates to the human receptor for advanced glycation end-products (RAGE), the Toll-like receptor 4 (TLR4) and the S100 calcium-binding protein A9 (S100A9), quantified by ELISA; (3) protection against Aß oligomer-induced neuronal cell death, using trypan blue to measure cell death in a murine neuronal cell line; (4) inhibition of TLR4 activation by S100A9, using a human TLR4 reporter cell line. We selected a 27-mer lead peptide that fulfilled these four criteria. This lead peptide is a privileged structure that displays inherent multitarget activity. This peptide is expected to significantly impact cognitive decline in mouse models of Alzheimer's disease, by targeting both neuroinflammation and neurodegeneration.

Isolation of Small Preantral Follicles from the Bovine Ovary Using a Combination of Fragmentation, Homogenization, and Serial Filtration.

Understanding the full process of mammalian folliculogenesis is crucial for improving assisted reproductive technologies in livestock, humans, and endangered species. Research has been mostly limited to antral and large preantral follicles due to difficulty in the isolation of smaller preantral follicles, especially in large mammals such as bovine species. This work presents an efficient approach to retrieve large numbers of small preantral follicles from a single bovine ovary. The cortex of individual bovine ovaries was sliced into 500 µm cubes using a tissue chopper and homogenized for 6 min at 9,000-11,000 rpm using a 10 mm probe. Large debris was separated from the homogenate using a cheese cloth, followed by serial filtration through 300 µm and 40 µm cell strainers. The contents retained in the 40 µm strainer were rinsed into a search dish, where follicles were identified and collected into a drop of medium. The viability of the collected follicles was tested via trypan blue staining. This method enables the isolation of a large number of viable small preantral follicles from a single bovine ovary in approximately 90 min. Importantly, this method is entirely mechanical and avoids the use of enzymes to dissociate the tissue, which may damage the follicles. The follicles obtained using this protocol can be used for downstream applications such as isolation of RNA for RT-qPCR, immunolocalization of specific proteins, and in vitro culture.

Multiplexed Single-Nucleus RNA Sequencing Using Lipid-Oligo Barcodes.

This protocol describes a robust pipeline for simultaneously analyzing multiple samples by single-nucleus (sn)RNA-seq. cDNA obtained from each single sample are labeled with the same lipid-coupled oligonucleotide barcode (10X Genomics). Nuclei from as many as 12 individual samples can be pooled together and simultaneously processed for cDNA library construction and subsequent DNA sequencing. While previous protocols using lipid-coupled oligonucleotide barcodes were optimized for analysis of samples consisting of viable cells, this protocol is optimized for analyses of quick-frozen cell samples. The protocol ensures efficient recovery of nuclei both by incorporating high sucrose buffered solutions and by including a tracking dye (trypan blue) during nuclei isolation. The protocol also describes a procedure for removing single nuclei 'artifacts' by removing cell debris prior to single nuclear fractionation. This protocol informs the use of computational tools for filtering poorly labeled nuclei and assigning sample identity using barcode unique molecular identifier (UMI) read counts percentages. The computational pipeline is applicable to either cultured or primary, fresh or frozen cells, regardless of their cell types and species. Overall, this protocol reduces batch effects and experimental costs while enhancing sample comparison. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Labeling cells with lipid oligo barcodes and generating multiplexed single-nucleus RNA-seq libraries Basic Protocol 2: Bioinformatic deconvolution of the multiplexed snRNAseq libraries.

Effects of 2-methoxyestradiol on hydrogen peroxide induced neuronal cell death and tau hyperphosphorylation.

AIMS: Alzheimer's Disease (AD) is characterized by progressive cognitive impairment, and memory loss. It has been shown that depletion of estrogens renders women vulnerable to AD with menopause women presenting higher risk for AD development than men. However, women under hormone replacement therapy (HRT) with 17ß-estradiol (E2) show lower risk for AD, implying that E2 may be protective. It has been shown that E2 exerts its effects through the estrogen receptor (ER) but also via its biologically active metabolites, 2-hydroxyestradiol (2OH), and 2-methoxyestradiol (2ME). We hypothesized that the neuroprotective effects of E2 are partly attributed to its metabolites. MATERIALS AND METHODS: SH-SY5Y neuronal cells were subjected oxidative stress (OS) cell death by hydrogen peroxide (H2O2), in the presence or absence of E2, 2ME and 2OH. Viability was assessed by trypan blue and thiazolyl blue tetrazolium bromide assays, intracellular OS with the Dichlorodihydrofluorescein Diacetate (DCFDA) assay, and Bax, p53 and PUMA quantified by RT-PCR. Tau hyperphosphorylation was studied by western blot. KEY FINDINGS: E2 and its metabolites 2OH and 2ME protect from cell death as assessed by the viability assays. Their effect was partly attributed to their antioxidant properties evidenced by the reduction of intracellular OS. Treatment with 2ME resulted in a reduction of Bax, but not p53 or PUMA in cells challenged with OS. Finally, 2ME was able to inhibit tau hyperphosphorylation as well. SIGNIFICANCE: E2 protects neuron cells partly through its metabolites. Further studies are needed to fully delineate the mechanism for this protection.

Quantitative analysis of cornea endothelial cell damage from enucleation, corneal buttoning, and storage in donor corneas using trypan blue dye staining.

We aimed to quantitatively analyze the corneal endothelial cell damage by measuring the area stained with trypan blue dye, and to confirm the degree of corneal endothelial cell damage resulting from enucleation, corneal buttoning, and storage in donor corneas intended for use in human corneal transplantation. This study was a retrospective analysis of medical records and videos recorded during keratoplasty. Twenty-one corneal buttons of 21 donors that underwent endothelial cell staining using trypan blue for the donor preparation during DALK or DMEK were included in the study. The percentage of stained area in entire corneal endothelia and the percentage of the stained area in the 8-mm diameter circle were quantitatively analyzed using Adobe Photoshop. The mean percentage of the stained area in the entire corneal endothelia in 13 corneas was 8.1 ±â€…13.3% (range, 0.0-56.1%), and the mean percentage of the stained area in a circle with a diameter of 8 mm in 21 corneas was 3.4 ±â€…5.2% (range, 0.0-18.9%). The correlations between the death-to-preservation time, the training duration of the residents who performed donor corneal buttoning, and the percentage of the stained area in the 8-mm diameter circle were not significant(P = .441, P = .495, respectively). Cornea thickness and endothelial cell density did not differ between 10 eyes in the group with the percentage of the stained area in a circle with a diameter of 8 mm <5% and 5 eyes in the group with the percentage more than 5% damage (P = .854, P = .358). The corneal endothelial cell damage could be quantitatively analyzed using trypan blue staining before keratoplasty in donor cornea. The amount of corneal endothelial cell damage in the central 8-mm circle was mostly acceptable, but some cases showed significantly severe endothelial cell damage. The corneal thickness and endothelial cell density did not differ between 10 eyes in the group with the percentage of the stained area in a circle with a diameter of 8 mm <5% and 5 eyes in the group with the percentage more than 5% damage. Therefore, pachymetry and specular microscopy are not sufficient for evaluating donor corneas before keratoplasty.

Involvement of Met receptor pathway in aggressive behavior of colorectal cancer cells induced by parathyroid hormone-related peptide.

BACKGROUND: Parathyroid hormone-related peptide (PTHrP) plays a key role in the development and progression of many tumors. We found that in colorectal cancer (CRC) HCT116 cells, the binding of PTHrP to its receptor PTHR type 1 (PTHR1) activates events associated with an aggressive phenotype. In HCT116 cell xenografts, PTHrP modulates the expression of molecular markers linked to tumor progression. Empirical evidence suggests that the Met receptor is involved in the development and evolution of CRC. Based on these data, we hypothesized that the signaling pathway trigged by PTHrP could be involved in the transactivation of Met and consequently in the aggressive behavior of CRC cells. AIM: To elucidate the relationship among PTHR1, PTHrP, and Met in CRC models. METHODS: For in vitro assays, HCT116 and Caco-2 cells derived from human CRC were incubated in the absence or presence of PTHrP (1-34) (10-8 M). Where indicated, cells were pre-incubated with specific kinase inhibitors or dimethylsulfoxide, the vehicle of the inhibitors. The protein levels were evaluated by Western blot technique. Real-time polymerase chain reaction (RT-qPCR) was carried out to determine the changes in gene expression. Wound healing assay and morphological monitoring were performed to evaluate cell migration and changes related to the epithelial-mesenchymal transition (EMT), respectively. The number of viable HCT116 cells was counted by trypan blue dye exclusion test to evaluate the effects of irinotecan (CPT-11), oxaliplatin (OXA), or doxorubicin (DOXO) with or without PTHrP. For in vivo tests, HCT116 cell xenografts on 6-wk-old male N:NIH (S)_nu mice received daily intratumoral injections of PTHrP (40 µg/kg) in 100 µL phosphate-buffered saline (PBS) or the vehicle (PBS) as a control during 20 d. Humanitarian slaughter was carried out and the tumors were removed, weighed, and fixed in a 4% formaldehyde solution for subsequent treatment by immunoassays. To evaluate the expression of molecular markers in human tumor samples, we studied 23 specimens obtained from CRC patients which were treated at the Hospital Interzonal de Graves y Agudos Dr. José Penna (Bahía Blanca, Buenos Aires, Argentina) and the Hospital Provincial de Neuquén (Neuquén, Neuquén, Argentina) from January 1990 to December 2007. Seven cases with normal colorectal tissues were assigned to the control group. Tumor tissue samples and clinical histories of patients were analyzed. Paraffin-embedded blocks from primary tumors were reviewed by hematoxylin-eosin staining technique; subsequently, representative histological samples were selected from each patient. From each paraffin block, tumor sections were stained for immunohistochemical detection. The statistical significance of differences was analyzed using proper statistical analysis. The results were considered statistically significant at P < 0.05. RESULTS: By Western blot analysis and using total Met antibody, we found that PTHrP regulated Met expression in HCT116 cells but not in Caco-2 cells. In HCT116 cells, Met protein levels increased at 30 min (P < 0.01) and at 20 h (P < 0.01) whereas the levels diminished at 3 min (P < 0.05), 10 min (P < 0.01), and 1 h to 5 h (P < 0.01) of PTHrP treatment. Using an active Met antibody, we found that where the protein levels of total Met decreased (3 min, 10 min, and 60 min of PTHrP exposure), the status of phosphorylated/activated Met increased (P < 0.01) at the same time, suggesting that Met undergoes proteasomal degradation after its phosphorylation/activation by PTHrP. The increment of its protein level after these decreases (at 30 min and 20 h) suggests a modulation of Met expression by PTHrP in order to improve Met levels and this idea is supported by our observation that the cytokine increased Met mRNA levels at least at 15 min in HCT116 cells as revealed by RT-qPCR analysis (P < 0.05). We then proceeded to evaluate the signaling pathways that mediate the phosphorylation/ activation of Met induced by PTHrP in HCT116 cells. By Western blot technique, we observed that PP1, a specific inhibitor of the activation of the proto-oncogene protein tyrosine kinase Src, blocked the effect of PTHrP on Met phosphorylation (P < 0.05). Furthermore, the selective inhibition of the ERK 1/2 mitogen-activated protein kinase (ERK 1/2 MAPK) using PD98059 and the p38 MAPK using SB203580 diminished the effect of PTHrP on Met phosphorylation/activation (P < 0.05). Using SU11274, the specific inhibitor of Met activation, and trypan blue dye exclusion test, Western blot, wound healing assay, and morphological analysis with a microscope, we observed the reversal of cell events induced by PTHrP such as cell proliferation (P < 0.05), migration (P < 0.05), and the EMT program (P < 0.01) in HCT116 cells. Also, PTHrP favored the chemoresistance to CPT-11 (P < 0.001), OXA (P < 0.01), and DOXO (P < 0.01) through the Met pathway. Taken together, these findings suggest that Met activated by PTHrP participates in events associated with the aggressive phenotype of CRC cells. By immunohistochemical analysis, we found that PTHrP in HCT116 cell xenografts enhanced the protein expression of Met (0.190 ± 0.014) compared to tumors from control mice (0.110 ± 0.012; P < 0.05) and of its own receptor (2.27 ± 0.20) compared to tumors from control mice (1.98 ± 0.14; P < 0.01). Finally, assuming that the changes in the expression of PTHrP and its receptor are directly correlated, we investigated the expression of both Met and PTHR1 in biopsies of CRC patients by immunohistochemical analysis. Comparing histologically differentiated tumors with respect to those less differentiated, we found that the labeling intensity for Met and PTHR1 increased and diminished in a gradual manner, respectively (P < 0.05). CONCLUSION: PTHrP acts through the Met pathway in CRC cells and regulates Met expression in a CRC animal model. More basic and clinical studies are needed to further evaluate the PTHrP/Met relationship.

[Establishment and preliminary clinical application of human intestinal fluid transplantation].

Objective: To explore and establish the preparation system of human intestinal fluid transplantation (HIFT) and HIFT capsule, and to preliminarily apply it to clinic. Methods: Strict standards for donor screening and management were established. The nasojejunal tube was catheterized into the distal jejunum, and then it was connected with an improved disposable sterile negative pressure collection device for the collection of human intestinal fluid. After that, it was prepared into capsules by filtering, adding 10% glycerin protectant and freeze-drying method. The amount of living bacteria was used as the standard of therapeutic dose. The living bacteria amount in fluid is ≥ 5.0×108 /mL and the living bacteria proportion is ≥ 83%; the living bacteria amount in powder is ≥ 2.0×106 /g and the living bacteria proportion is ≥ 81%; The observational indicators included: (1) the basic information of the donor, the amount of living bacteria in the HIF and powder. (2) Preliminary analysis of the treatment for ASD, which combined HIFT capsule with standard FMT capsule, from February to December 2021 (Clinical trial Registration Number: ChiCTR2100043929). Evaluation criteria: Trypan blue staining method was used to detect the living bacteria amount in fluid and powder. The Autism Behavior Checklist (ABC) and Childhood Autism Rating Scale (CARS) were used to evaluate the efficacy. Results: Compared with the parent donor, the standard donor was younger [(25.4±0.9) y vs. (30.7±3.2) y, t=-19.097, P=0.001] and had a lower body mass index [(19.7±0.5) kg/m2 vs. (20.8±1.3) kg/m2, t=-8.726, P=0.001], more in the living bacteria amount in powder [(7.47±1.52)×106/g vs. (5.03±1.38)×106/g, t=11.331, P=0.031], Chao index (205.4±6.8 vs. 194.2±7.2, t=10.415, P=0.001), and Shannon index (3.25±0.14 vs 2.72±0.27, t=19.465, P=0.001). The differences were statistically significant (all P<0.05). However, there were no significant differences in gender, drainage volume and total number of bacterial liquid colonies between the two groups (all P>0.05). Both the standard donor and the parent donor met the donor screening criteria, and the preparation fluid and powder met the treatment criteria. Eight patients received the treatment of HIFT combined with fecal microbiota transplantation (FMT). Preliminary statistical results showed that HIFT combined with FMT improved ABC and CARS at the 1st, 2nd, 3rd and 4th months. The differences were statistically significant (all P<0.05). No severe adverse reaction occurred. Conclusion: Based on the previous research on FMT preparation system and the clinical technology in our center, this study developed a high standard HIFT preparation system, and explored the clinical study of HIFT combined with FMT, in order to provide an innovative therapy for the treatment of diseases.

Excessive Zinc Ion Caused PC12 Cell Death Correlating with Inhibition of NOS and Increase of RAGE in Cells.

Zinc ion (Zn2+) is an important functional factor; however, excessive Zn2+ can be toxic. To understand the neurotoxicity of excessive Zn2+ and the underlying mechanism, PC12 cells were treated with excessive Zn2+ and Zn2+ plus N, N, N', N'-Tetrakisethylenediamine (TPEN), a zinc ion chelator agent. Trypan blue and 3-(4,5-dimethyl-2- thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, thiazolyl blue tetrazolium bromide (MTT) assays were used to test cell viability; the relative kits were used to detect the activity of NOS synthase and the content of the receptor for advanced glycation end product (RAGE) in cells. We observed that excessive zinc caused PC12 cell damage and that TPEN partially reversed cell damage caused by excessive zinc. In addition, excessive zinc decreased total nitric oxide synthase (TNOS) activity in cells, in which constitutive nitric oxide synthase (cNOS) activity was significantly reduced; however, inducible nitric oxide synthase (iNOS) activity was extremely promoted. Moreover, excessive zinc upregulated the expression of RAGE, and TPEN effectively reversed the increase in RAGE induced by excessive zinc ions. Therefore, we concluded that excessive zinc caused PC12 cell damage, correlating with the inhibition of NOS and increase of RAGE induced in cells.

Subconjunctival Lymphatics Respond to VEGFC and Anti-Metabolites in Rabbit and Mouse Eyes.

Purpose: To characterize and pharmacologically influence subconjunctival lymphatics in rabbit and mouse eyes. Methods: Rabbits received subconjunctival injections of trypan blue or fixable fluorescent dextrans. Bleb-related outflow pathways were quantified. Immunofluorescence for vessel-specific markers (lymphatics [podoplanin and LYVE-1] and blood vessels [CD31]) were performed in native rabbit conjunctiva and after fixable fluorescent dextran injection. Vascular endothelial cell growth factor-C (VEGFC) was injected subconjunctivally in rabbits. mRNA and protein were assessed for the above markers using RT-PCR and Western blot. Alternatively, mouse studies used Prox1-tdTomato transgenic reporter mice. Subconjunctival injection conditions included: no injection, balanced salt solution (BSS), VEGFC, 5-fluorouracil (5FU) and two concentrations of mitomycin-C (MMC). Two mouse injection protocols (short and long) with different follow-up times and number of injections were performed. Mouse eyes were enucleated, flat mounts created, and subconjunctival branching and length assessed. Results: Rabbit eyes demonstrated clear bleb-related subconjunctival outflow pathways that were distinct from blood vessels and were without nasal/temporal predilection. Immunofluorescence against vessel-specific markers showed lymphatics and blood vessels in rabbit conjunctiva, and these lymphatics overlapped with bleb-related subconjunctival outflow pathways. Subconjunctival VEGFC increased lymphatic (P = 0.004-0.04) but not blood vessel (P = 0.77-0.84) mRNA or protein in rabbits. Prox1-tdTomato transgenic reporter mice demonstrated natively fluorescent lymphatics. Subconjunctival VEGFC increased murine lymphatic branching and length (P ≤ 0.001-0.004) while antimetabolites (P ≤ 0.001-0.043) did the opposite for the long protocol. Discussion: Subconjunctival lymphatics are pharmacologically responsive to both VEGFC and antimetabolites in two animal models studied using different methodologies. These results may be important for bleb-forming glaucoma surgeries or ocular drug delivery.

Simvastatin Coadministration Modulates the Electrostatically Driven Incorporation of Doxorubicin into Model Lipid and Cell Membranes.

Understanding the interactions between drugs and lipid membranes is a prerequisite for finding the optimal way to deliver drugs into cells. Coadministration of statins and anticancer agents has been reported to have a positive effect on anticancer therapy. In this study, we elucidate the mechanism by which simvastatin (SIM) improves the efficiency of biological membrane penetration by the chemotherapeutic agent doxorubicin (DOX) in neutral and slightly acidic solutions. The incorporation of DOX, SIM, or a combination of them (DOX:SIM) into selected single-component lipid membranes, zwitterionic unsaturated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), neutral cholesterol, and negatively charged 1,2-dimyristoyl-sn-glycero-3-phospho-l-serine (DMPS) was assessed using the Langmuir method. The penetration of neutral lipid monolayers by the codelivery of SIM and DOX was clearly facilitated at pH 5.5, which resembles the pH conditions of the environment of cancer cells. This effect was ascribed to partial neutralization of the DOX positive charge as the result of intermolecular interactions between DOX and SIM. On the other hand, the penetration of the negatively charged DMPS monolayer was most efficient in the case of the positively charged DOX. The efficiency of the drug delivery to the cell membranes was evaluated under in vitro conditions using a panel of cancer-derived cell lines (A172, T98G, and HeLa). MTS and trypan blue exclusion assays were performed, followed by confocal microscopy and spheroid culture tests. Cells were exposed to either free drugs or drugs encapsulated in lipid carriers termed cubosomes. We demonstrated that the viability of cancer cells exposed to DOX was significantly impaired in the presence of SIM, and this phenomenon was greatly magnified when DOX and SIM were coencapsulated in cubosomes. Overall, our results confirmed the utility of the DOX:SIM combination delivery, which enhances the interactions between neutral components of cell membranes and positively charged chemotherapeutic agents.

P-15†Utilising endothelial migration to perform deep anterior lamellar keratoplasty in eyes with deep posterior corneal scarring typically treated with penetrating keratoplasty.

*Correspondence - Luis García-Onrubia: luis.garciaonrubia@gstt.nhs.uk PURPOSE: To describe a novel technique for deep anterior lamellar keratoplasty (DALK) in patients central corneal perforation and deep scarring making conventional DALK (Melles or Big Bubble) unviable. A posterior Descemet's membrane (DM) skirt has provided an adequate scaffold for the migration of the host endothelial cells. METHODS AND ANALYSIS: A case report. A 32-year-old male with previous hydrops developed severe corneal scarring with a break in DM visible on OCT scanning. A modified DALK procedure was perform consisting of a 400µm, 8.5mm Anterior lamellar cap with a 4.5mm posterior lamellar disc, denuded of endothelial cells and containing a DM skirt.Initially, manual dissection of the and anterior 400µm of corneal stroma was performed using a modified Melles technique. The residual posterior lamellar was assessed and found to have significant residual scarring. A central 4mm optical window was performed through the posterior lamellar over the visual axis.The donor tissue was cut using a 350µm microkeratome head. The anterior cap was trephined to 8.5mm and set aside. The posterior lamellar was placed in a punch block, and the endothelial was removed using a silicone tipped cannula. The removal of endothelial cells was confirmed using trypan blue dye. A posterior lamellar graft with a 4.0mm stromal bed and a 4.5mm DM skirt was fashion using a peeling and double punch technique. The posterior lamellar graft was inserted into the optical window such that the DM skirt provided a bridge to the donor corneal endothelium. The anterior cap was sutured with a double continuous suture of 10-0 monofilament nylon. An inferior peripheral iridotomy was created, and an air bubble filling the anterior chamber was left at the end of the case. RESULTS: The preoperative visual acuity (VA) was hand movements. Full attachment of the posterior lamellar was seen at all time-points from week one onwards. Central corneal pachymetry continued to reduce for 12 weeks. One year after the operation, with sutures in, the best spectacle-corrected VA was 6/12. The corneal graft was clear, and no rejection episodes occurred. Endothelial cell repopulation of the donor DM could be observed with specular microscopy. CONCLUSION: The presence of DM promotes endothelial migration and healing. Modifications to traditional DALK surgery, in which DM is used to promote endothelial healing, are a viable alternative to penetrating keratoplasty. This method eliminates the risk of allograft endothelial rejection and allows a 'regenerative' for DALK to be used, offering a new modality of treatment in patients with healthy reserves of endothelial cells and deep posterior lamellar scarring.

New dual dye for vitreoretinal surgery with increased transparency.

OBJECTIVES: To develop a new dye formulation for vitreoretinal surgery, which shows increased transparency for better intraoperative handling with better parameters important for use. METHODS AND ANALYSIS: A new blue dye, DDG, was synthesised and tested for toxicity and staining. Diglycerol as new density-increasing additive was identified, and its toxicity and lack of influence of the staining with trypan blue (TB) on a collagen membrane as model for the epiretinal membrane was determined. Transparency of the dye solution was evaluated. RESULTS: DDG is as alternative to Brilliant Blue G (BBG), with good staining properties for interna limitans models, and a good safety profile. Diglycerol is a new non-toxic additive replacing PEG3350, with reduced viscosity and no reduction in staining, allowing the reduction of TB to achieve the same staining level of the collagen membrane by 40%, with greater transparency of the dye solution and reduced viscosity. Both factors should facilitate a safe removal during surgery. CONCLUSION: A new dye preparation with improved performance in comparison to marketed combinations of BBG and TB was developed. Its reduced TB concentration and viscosity with maintained density allow better tolerance and handling.

MSC-Derived exosomes suppress colorectal cancer cell proliferation and metastasis via miR-100/mTOR/miR-143 pathway.

Exosomes derived from mesenchymal stem cells (MSCs) are mostly responsible for the therapeutic effects of MSCs. To show the therapeutic effects of the human bone marrow MSC-derived exosomes (MSC-Exos) on colorectal cancer (CRC) and explore the molecular cross-talks between them, CRC cells were treated with the MSC-Exos. We found that MSC-Exos were enriched with miR-100 and miR-143, which effectively downregulated mTOR, Cyclin D1, K-RAS, HK2 while upregulated p-27 expression. All these effects were reversed by concurrent treatment with MSC-Exos and antagomiR-100, confirming that they were caused by exosomal transfer of miR-100 into recipient CRC cells. Moreover, exosomal miR-100 promoted endogenous miR-143 expression. The flow cytometry, MTT and trypan blue assays revealed that MSC-Exos could efficiently suppress proliferation and induce apoptosis of the CRC cells. Furthermore, wound healing, transwell migration and invasion assays confirmed their inhibitory effects on the migration and invasiveness of SW480 cells. We further confirmed these effects by analyzing the expression levels of epithelial to mesenchymal transition (EMT) factors and metastasis-related genes. Results showed that MSC-Exos significantly suppressed the expression of MMP2 and MMP9 (metastasis-related genes), SNAIL and TWIST (EMT-inducing transcription factors), Vimentin and N-cadherin (mesenchymal cell markers), whereas E-cadherin (epithelial cell marker) was remarkably up-regulated. Collectively, our data indicated that MSC-Exos could suppress proliferation, migration, invasion and metastasis while inducing the apoptosis of the CRC cells via miR-100/mTOR/miR-143 axis. Our findings highlight that MSC-Exo treatment as well as miR-100 restoration might be considered as potential therapeutic strategies for CRC.