Exploring Stem-Cell-Based Therapies for Retinal Regeneration.

The escalating prevalence of retinal diseases-notably, age-related macular degeneration and hereditary retinal disorders-poses an intimidating challenge to ophthalmic medicine, often culminating in irreversible vision loss. Current treatments are limited and often fail to address the underlying loss of retinal cells. This paper explores the potential of stem-cell-based therapies as a promising avenue for retinal regeneration. We review the latest advancements in stem cell technology, focusing on embryonic stem cells (ESCs), pluripotent stem cells (PSCs), and mesenchymal stem cells (MSCs), and their ability to differentiate into retinal cell types. We discuss the challenges in stem cell transplantation, such as immune rejection, integration into the host retina, and functional recovery. Previous and ongoing clinical trials are examined to highlight the therapeutic efficacy and safety of these novel treatments. Additionally, we address the ethical considerations and regulatory frameworks governing stem cell research. Our analysis suggests that while stem-cell-based therapies offer a groundbreaking approach to treating retinal diseases, further research is needed to ensure long-term safety and to optimize therapeutic outcomes. This review summarizes the clinical evidence of stem cell therapy and current limitations in utilizing stem cells for retinal degeneration, such as age-related macular degeneration, retinitis pigmentosa, and Stargardt's disease.

Biomarkers of ocular allergy and dry eye disease.

The most common disorders of the ocular surface are dry eye disease (DED) and ocular allergy (OA). These conditions are frequently coexisting with or without a clinical overlap and can cause a severe impact on the patient's quality of life. Therefore, it can sometimes be hard to distinguish between DED and OA because similar changes and manifestations may be present. Atopic patients can also develop DED, which can aggravate their manifestations. Moreover, patients with DED can develop ocular allergies, so these two pathological entities of the ocular surface can be considered as mutual conditions that share the same background. Nowadays, by using different techniques to collect tissue from ocular surfaces, the changes in molecular homeostasis can be detected and this can lead to a precise diagnosis. The article provides an up-to-date review of the various ocular surface biomarkers that have been identified in DED, OA, or both conditions. Abbreviations: DED = dry eye disease, OA = ocular allergy, SS = Sjogren syndrome, TBUT = tear break up time, TFO = tear film osmolarity, AKC = Atopic keratoconjunctivitis, ANXA1 = Annexin 1, ANXA11 = Annexin 11, CALT = Conjunctival associated lymphoid tissue, CCL2/MIP-1 = Chemokine (C-C motif) ligand2/Monocyte chemoattractant protein 1, CCL3/MIP-1α = Chemokine (C-C motif) ligand 3/Macrophage inflammatory protein 1 alpha, CCL4/MIP-1ß = Chemokine (C-C motif) ligand 4/Macrophage inflammatory protein 1 beta, CCL5/RANTES = Chemokine (C-C motif) ligand 5 /Regulated on Activation, Normal T cell Expressed and Secreted, CCR2 = Chemokine (C-C motif) receptor 2, CCR5 = Chemokine (C-C motif) receptor 5, CD3+ = Cluster of differentiation 3 positive, CD4+ = Cluster of differentiation 4 positive, CD8+ = Cluster of differentiation 8 positive, CGRP = Calcitonin-gene-related peptide, CX3CL1 C-X3 = C motif -chemokine ligand 1 /Fractalkine, CXCL8 = Chemokine (C-X-C motif) ligand 8, CXCL9 = Chemokine (C-X-C motif) ligand 9, CXCL10 = Chemokine (C-X-C motif) ligand 10, CXCL11 = Chemokine (C-X-C motif) ligand 11, CXCL12 = Chemokine (C-X-C motif) ligand 12, CXCR4 = Chemokine (C-X-C motif) receptor 4, EGF = Epidermal growth factor, HLA-DR = Human leukocyte antigen-D-related, ICAM-1 = Intercellular adhesion molecule 1, IFN-γ = Interferon-gamma, IgG = Immunoglobulin G, IgE = Immunoglobulin E, IL-1 = Interleukin-1, IL-1α = Interleukin-1 alpha, IL-1ß = Interleukin-1 beta, CGRP = Calcitonin-Gene-Related Peptide, IL-3 = Interleukin-3, IL-4 = Interleukin-4, IL-6 = Interleukin-6, IL-8 = Interleukin-8, IL-10 = Interleukin-10, IL-17 = Interleukin-17, IL-17A = Interleukin-17A, LPRR3 = Lacrimal proline-rich protein 3, LPRR4 = Lacrimal proline-rich protein 4, MUC5AC = Mucin 5 subtype AC, oligomeric mucus/gel-forming, MUC16 = Mucin 16, OCT = Optical coherence tomography, OGVHD = Ocular graft versus host disease, PAX6 = Paired-box protein 6, VKC = Vernal keratoconjunctivitis, TGF-ß = Transforming growth factor ß, S100 = proteins Calcium activated signaling proteins, Th1 = T helper 1 cell, Th17 = T helper 17 cell, MGD = Meibomian gland dysfunction, TFOS = Tear film and ocular surface society, SS-KCS = Keratoconjunctivitis Sicca, MMP-9 = Matrix metalloproteinase 9, MMP-1 = Matrix metalloproteinase 1, ZAG = Zinc alpha glycoprotein, CBA = Cytometric bead array, MALDI TOF-MS = matrix assisted laser desorption ionization-time of flight, SELDI TOF-MS = surface-enhanced laser desorption ionization-time of flight, IVCM = in vivo confocal microscopy, AS-OCT = anterior segment optical coherence tomography, iTRAQ = Isobaric tags for relative and absolute quantitation, LC-MS = Liquid chromatography-mass spectrometry, LCN-1 = lipocalin 1, PIP = prolactin induced protein, NGF = Nerve growth factor, PRR4 = proline rich protein 4, VIP = Vasoactive intestinal peptide, ELISA = enzyme linked immunoassay, TNF-α = tumor necrosis factor alpha, PAC = perennial allergic conjunctivitis, SAC = seasonal allergic conjunctivitis, IC = impression cytology, RT-PCR = reverse transcription polymerase chain reaction, PCR = polymerase chain reaction, APCs = antigen-presenting cells, NK cells = natural killer cells, HEL = hexanoyl-lysine, 4-HNE = 4-hydroxy-2-nonenal, MDA = malondialdehyde.

Controlled Electronic and Magnetic Landscape in Self-Assembled Complex Oxide Heterostructures.

Complex oxide heterointerfaces contain a rich playground of novel physical properties and functionalities, which give rise to emerging technologies. Among designing and controlling the functional properties of complex oxide film heterostructures, vertically aligned nanostructure (VAN) films using a self-assembling bottom-up deposition method presents great promise in terms of structural flexibility and property tunability. Here, the bottom-up self-assembly is extended to a new approach using a mixture containing a 2Dlayer-by-layer film growth, followed by a 3D VAN film growth. In this work, the two-phase nanocomposite thin films are based on LaAlO3 :LaBO3 , grown on a lattice-mismatched SrTiO3001 (001) single crystal. The 2D-to-3D transient structural assembly is primarily controlled by the composition ratio, leading to the coexistence of multiple interfacial properties, 2D electron gas, and magnetic anisotropy. This approach provides multidimensional film heterostructures which enrich the emergent phenomena for multifunctional applications.

Intrastromal Injections in the Management of Infectious Keratitis.

Infectious keratitis is a major global cause of vision loss and blindness. Prompt diagnosis and targeted antibiotic treatment are crucial for managing the condition. Topical antimicrobials are the most effective therapy for bacterial keratitis, but they can lead to unsatisfactory results due to ocular perforation, scarring, and melting. Intrastromal injection is a newer technique for delivering antimicrobials directly to the site of infection and has been successful in treating severe, treatment-resistant infectious keratitis, especially when surgery is not recommended. In cases where deep stromal disease is resistant to topical treatment, intrastromal antimicrobial injections may be necessary to achieve higher drug concentration at the infection site. However, the use of intrastromal antibiotics is limited, as topical antibacterial agents have better penetration than antifungal agents. Bacterial and fungal keratitis have been extensively researched for intrastromal medication injections, while there is limited evidence for viral keratitis. This review emphasizes the potential of intrastromal antimicrobial injections as an alternative for managing severe refractory infectious keratitis. The technique offers direct targeting of the infection site and faster resolution in some cases compared to topical therapy. However, further research is needed to determine the safest antimicrobials options, minimal effective doses, and concentrations for various pathogens. Intrastromal injections may serve as a non-surgical treatment option in high-risk cases, with benefits including direct drug delivery and reduced epithelial toxicity. Despite promising findings, more studies are required to confirm the safety and efficacy of this approach.

Ocular Complications of Radiotherapy in Uveal Melanoma.

Uveal melanoma is the most common primary malignant intraocular tumor in adults. Radiation therapy has replaced enucleation and is now the preferred treatment in most cases. Nonetheless, around 70% of patients develop radiation-related complications, some of which are vision-threatening. The objective of this review is to present the most important complications associated with radiotherapy in the treatment of uveal melanoma and their pathogenesis, incidence, risk factors, and available preventive and therapeutic measures. The most common complications are cataracts, with a reported incidence ranging from 4% to 69%, and radiation retinopathy, reported in 5-68% of cases. Radiation-related complications are responsible for approximately half of secondary enucleations, the leading cause being neovascular glaucoma. A poor visual outcome is mainly associated with the presence of radiation retinopathy and radiation optic neuropathy. Therapeutic options are available for the majority of complications with the notable exception of optic neuropathy. However, many studies report a final visual acuity of less than 20/200 in more than 60% of treated eyes. Reducing complication rates can be achieved by lowering the dose of radiation, with the use of eccentric, customized plaques and careful planning of the irradiation delivery in order to protect structures vital to vision and by associating radiation therapy with other methods with the aim of reducing tumor volume.

Diagnostic difficulties in giant benign phyllodes tumor.

Phyllodes tumors (PTs) are rare tumors of the breast, which encompass both stromal and epithelial components. The maximum incidence is in the fourth decade of life. Most of these tumors are benign, but about one third can be malignant acting as sarcomas. Due to their rarity and atypical clinical behavior (especially for the giant ones), the management of these tumors is usually difficult. We report a case of a 24-year-old woman who presented in the Department of Oncology for rapid increase in volume of the left breast. She had no personal pathological or family history. Initial clinical exam showed a large irregular mass in the left breast of approximately 30 cm and palpable lymph nodes in the ipsilateral axilla. A core needle biopsy for the tumor was performed with histopathological (HP) result that revealed an aspect suggesting fibroadenoma/PT. Contrast-enhanced computed tomography (CT) scan identified lymph node enlargement in the left axilla and a peripheral nodule in the lung about 5.5/3.4 mm with no specific features. The patient was then transferred to the Department of Surgery, where left mastectomy and axillary lymph node sampling were performed. HP result of the surgical specimens confirmed the presence of both fibroadenoma and PT, with clear margins above 1 cm, but recommended immunohistochemistry (IHC) to clearly specify benign versus borderline type. Five lymph nodes out of six resected presented microscopic reactive changes. We performed a search of literature using the keywords "giant", "benign" and "phyllodes". The results were used to summarize and discuss some of the main features of this type of tumors as well as diagnostic and therapeutic difficulties.

Retroperitoneal Functioning Paraganglioma--A Rare Case of Secondary Diabetes.

INTRODUCTION: Paragangliomas are rare neuroendocrine tumors that arise from the extra-adrenal autonomic paraganglia, which can derive from either parasympathetic or sympathetic paraganglia and are closely related to pheochromocytomas. CASE REPORT: We present the case of a young male patient of 37 years old, who was admitted for hypertensive crisis and palpitations. His medical history included medically controlled type 2 diabetes mellitus, (diagnosed 10 months ago), Hepatitis A. Hormonal evaluation revealed elevated urinary metanephrines and normetanephrines, with mainly increased normetanephrines (2330 ug/24 h). Plasmatic metanephrins were in normal range, but levels of plasmatic normetanephrins were elevated (952 pg/ml). The assessment of pituitary and aldosterone-renin axis values were within normal limits. Abdominal computed tomography showed left adrenal nodular lesion on the external arm, bilobulated, size 32/33 mm with maximum axial and cranio-caudal diameter of approx. 45 cm, suggestive of a benign lesion, keeping the cleavage plane to vecinatate structures. Left adrenalectomy was performed by laparoscopic approach. We mention that immediately after induction of anesthesia were recorded blood pressures of 298/143 mmHg. Histopathologic and immunohistochemical examination diagnose paraganglioma, without invasion of adjacent tissues. The patient evolution was favorable, with the remission of the symptoms and normalization of hormonal markers. It is imperative to note the remission of diabetes in the postoperative period. DISCUSSION: This is the case of a young patient with functional retroperitoneal paraganglioma, who presented with symptoms of pheochromocytoma. Compared to pheochromocytomas, paragangliomas are rarely symptomatic and functional. Association with diabetes is even more rare. Specialized investigations allowed the proper diagnosis and the therapeutic approach above was the result of a multidisciplinary cooperation.

Subliminal perception of complex visual stimuli.

Rationale: Unconscious perception of various sensory modalities is an active subject of research though its function and effect on behavior is uncertain. Objective: The present study tried to assess if unconscious visual perception could occur with more complex visual stimuli than previously utilized. Methods and Results: Videos containing slideshows of indifferent complex images with interspersed frames of interest of various durations were presented to 24 healthy volunteers. The perception of the stimulus was evaluated with a forced-choice questionnaire while awareness was quantified by self-assessment with a modified awareness scale annexed to each question with 4 categories of awareness. At values of 16.66 ms of stimulus duration, conscious awareness was not possible and answers regarding the stimulus were random. At 50 ms, nonrandom answers were coupled with no self-reported awareness suggesting unconscious perception of the stimulus. At larger durations of stimulus presentation, significantly correct answers were coupled with a certain conscious awareness. Discussion: At values of 50 ms, unconscious perception is possible even with complex visual stimuli. Further studies are recommended with a focus on a range of interest of stimulus duration between 50 to 16.66 ms.

Fingolimod, a sphingosine-1 phosphate receptor modulator, increases BDNF levels and improves symptoms of a mouse model of Rett syndrome.

The functional relevance of brain-derived neurotrophic factor (BDNF) is beginning to be well appreciated not only in mice, but also in humans. Because reduced levels typically correlate with impaired neuronal function, increasing BDNF levels with well-tolerated drugs diffusing into the central nervous system may help in ameliorating functional deficits. With this objective in mind, we used the sphingosine-1 phosphate receptor agonist fingolimod, a drug that crosses the blood-brain barrier. In addition, fingolimod has recently been introduced as the first oral treatment for multiple sclerosis. In cultured neurons, fingolimod increases BDNF levels and counteracts NMDA-induced neuronal death in a BDNF-dependent manner. Ongoing synaptic activity and MAPK signaling is required for fingolimod-induced BDNF increase, a pathway that can also be activated in vivo by systemic fingolimod administration. Mice lacking Mecp2, a gene frequently mutated in Rett syndrome, show decreased levels of BDNF, and fingolimod administration was found to partially rescue these levels as well as the size of the striatum, a volumetric sensor of BDNF signaling in rodents. These changes correlate with increased locomotor activity of the Mecp2-deficient animals, suggesting that fingolimod may improve the functional output of the nervous system, in addition to its well-documented effects on lymphocyte egress from lymph nodes.

BDNF and its pro-peptide are stored in presynaptic dense core vesicles in brain neurons.

Although brain-derived neurotrophic factor (BDNF) regulates numerous and complex biological processes including memory retention, its extremely low levels in the mature central nervous system have greatly complicated attempts to reliably localize it. Using rigorous specificity controls, we found that antibodies reacting either with BDNF or its pro-peptide both stained large dense core vesicles in excitatory presynaptic terminals of the adult mouse hippocampus. Both moieties were ~10-fold more abundant than pro-BDNF. The lack of postsynaptic localization was confirmed in Bassoon mutants, a seizure-prone mouse line exhibiting markedly elevated levels of BDNF. These findings challenge previous conclusions based on work with cultured neurons, which suggested activity-dependent dendritic synthesis and release of BDNF. They instead provide an ultrastructural basis for an anterograde mode of action of BDNF, contrasting with the long-established retrograde model derived from experiments with nerve growth factor in the peripheral nervous system.

Hippocampal enlargement in Bassoon-mutant mice is associated with enhanced neurogenesis, reduced apoptosis, and abnormal BDNF levels.

Mice mutant for the presynaptic protein Bassoon develop epileptic seizures and an altered pattern of neuronal activity that is accompanied by abnormal enlargement of several brain structures, with the strongest size increase in hippocampus and cortex. Using manganese-enhanced magnetic resonance imaging, an abnormal brain enlargement was found, which is first detected in the hippocampus 1 month after birth and amounts to an almost 40% size increase of this structure after 3 months. Stereological quantification of cell numbers revealed that enlargement of the dentate gyrus and the hippocampus proper is associated with larger numbers of principal neurons and of astrocytes. In search for the underlying mechanisms, an approximately 3-fold higher proportion of proliferation and survival of new-born cells in the dentate gyrus was found to go hand in hand with similarly larger numbers of doublecortin-positive cells and reduced numbers of apoptotic cells in the dentate gyrus and the hippocampus proper. Enlargement of the hippocampus and of other forebrain structures was accompanied by increased levels of brain-derived neurotrophic factor (BDNF). These data show that hippocampal overgrowth in Bassoon-mutant mice arises from a dysregulation of neurogenesis and apoptosis that might be associated with unbalanced BDNF levels.

The 10q25.3-26.1 G protein-coupled receptor gene GPR26 is epigenetically silenced in human gliomas.

Loss of heterozygosity (LOH) of the entire chromosome 10 is the most frequent genetic alteration in human glioblastoma (GBM). In addition to PTEN/MMAC1 on 10q23.3, clustering of partial deletion break-points on 10q25.3-26.1 points to a second suppressor locus. The proposed target gene DMBT1 was not confirmed. By somatic deletion mapping of this region, we identified the complementary DNA encoding the human homologue of rat orphan G protein-coupled receptor GPR26. GPR26 is highly expressed in fetal and adult brain, but frequently reduced or absent in glioma cells and biopsies, due to de novo methylation of its 5' CpG island. Silencing of GPR26 was reversed with 5-aza-deoxycytidine and the histone deacetylase inhibitor trichostatin A. Furthermore, overexpression of GPR26 in HEK and in U87 glioma cells increased intracellular cAMP concentration which is considered to induce astrocytic differentiation. Interestingly, we observed concomitant silencing of GPR26 with O6-methylguanine-DNA methyl transferase (MGMT), a DNA repair gene co-localized on 10q25.3-26.1 (p=0.0001). We conclude that epigenetic silencing is a common mechanism in malignant gliomas that simultaneously inactivates MGMT and GPR26. The 10q25.3-26.1 region may contain an important epigenetic pathway in brain tumorigenesis.

Tenascin-C is a novel RBPJkappa-induced target gene for Notch signaling in gliomas.

Tenascin-C (TNC) expression is known to correlate with malignancy in glioblastoma (GBM), a highly invasive and aggressive brain tumor that shows limited response to conventional therapies. In these malignant gliomas as well as in GBM cell lines, we found Notch2 protein to be strongly expressed. In a GBM tumor tissue microarray, RBPJk protein, a Notch2 cofactor for transcription, was found to be significantly coexpressed with TNC. We show that the TNC gene is transactivated by Notch2 in an RBPJk-dependent manner mediated by an RBPJk binding element in the TNC promoter. The transactivation is abrogated by a Notch2 mutation, which we detected in the glioma cell line Hs683 that does not express TNC. This L1711M mutation resides in the RAM domain, the site of interaction between Notch2 and RBPJk. In addition, transfection of constructs encoding activated Notch2 or Notch1 increased endogenous TNC expression identifying TNC as a novel Notch target gene. Overexpression of a dominant negative form of the transcriptional coactivator MAML1 or knocking down RBPJk in LN319 cells led to a dramatic decrease in TNC protein levels accompanied by a significant reduction of cell migration. Because addition of purified TNC stimulated glioma cell migration, this represents a mechanism for the invasive properties of glioma cells controlled by Notch signaling and defines a novel oncogenic pathway in gliomagenesis that may be targeted for therapeutic intervention in GBM patients.

Local targeting of malignant gliomas by the diffusible peptidic vector 1,4,7,10-tetraazacyclododecane-1-glutaric acid-4,7,10-triacetic acid-substance p.

PURPOSE: Malignant glial brain tumors consistently overexpress neurokinin type 1 receptors. In classic seed-based brachytherapy, one to several rigid (125)I seeds are inserted, mainly for the treatment of small low-grade gliomas. The complex geometry of rapidly proliferating high-grade gliomas requires a diffusible system targeting tumor-associated surface structures to saturate the tumor, including its margins. EXPERIMENTAL DESIGN: We developed a new targeting vector by conjugating the chelator 1,4,7,10-tetraazacyclododecane-1-glutaric acid-4,7,10-triacetic acid to Arg(1) of substance P, generating a radiopharmaceutical with a molecular weight of 1,806 Da and an IC(50) of 0.88 +/- 0.34 nmol/L. Cell biological studies were done with glioblastoma cell lines. neurokinin type-1 receptor (NK1R) autoradiography was done with 58 tumor biopsies. For labeling, (90)Y was mostly used. To reduce the "cross-fire effect" in critically located tumors, (177)Lut and (213)Bi were used instead. In a pilot study, we assessed feasibility, biodistribution, and early and long-term toxicity following i.t. injection of radiolabeled 1,4,7,10-tetraazacyclododecane-1-glutaric acid-4,7,10-triacetic acid substance P in 14 glioblastoma and six glioma patients of WHO grades 2 to 3. RESULTS: Autoradiography disclosed overexpression of NK1R in 55 of 58 gliomas of WHO grades 2 to 4. Internalization of the peptidic vector was found to be specific. Clinically, the radiopharmeutical was distributed according to tumor geometry. Only transient toxicity was seen as symptomatic radiogenic edema in one patient (observation period, 7-66 months). Disease stabilization and/or improved neurologic status was observed in 13 of 20 patients. Secondary resection disclosed widespread radiation necrosis with improved demarcation. CONCLUSIONS: Targeted radiotherapy using diffusible peptidic vectors represents an innovative strategy for local control of malignant gliomas, which will be further assessed as a neoadjuvant approach.

Ligands for natural killer cell-activating receptors are expressed upon the maturation of normal myelomonocytic cells but at low levels in acute myeloid leukemias.

Natural killer (NK) cell-mediated cytolytic activity against tumors requires the engagement of activating NK receptors by the tumor-associated ligands. Here, we have studied the role of NKG2D and natural cytotoxicity receptors (NCRs) in the recognition of human leukemia. To detect as-yet-unknown cell-surface molecules recognized by NCRs, we developed soluble forms of NKp30, NKp44, and NKp46 as staining reagents binding the putative cognate ligands. Analysis of UL16-binding protein-1 (ULBP1), ULBP2, and ULBP3 ligands for NKG2D and of potential ligands for NKp30, NKp44, and NKp46 in healthy hematopoietic cells demonstrated the ligand-negative phenotype of bone marrow-derived CD34(+) progenitor cells and the acquisition of cell-surface ligands during the course of myeloid differentiation. In acute myeloid leukemia (AML), leukemic blasts from approximately 80% of patients expressed very low levels of ULBPs and NCR-specific ligands. Treatment with differentiation-promoting myeloid growth factors, together with interferon-gamma, upregulated cell-surface levels of ULBP1 and putative NCR ligands on AML blasts, conferring an increased sensitivity to NK cell-mediated lysis. We conclude that the ligand-negative/low phenotype in AML is a consequence of cell maturation arrest on malignant transformation and that defective expression of ligands for the activating NKG2D and NCR receptors may compromise leukemia recognition by NK cells.