“Melanoma inhibitory activity” (MIA): a promising serological tumour marker in metastatic uveal melanoma

Purpose To assess the role of “melanoma inhibitory activity” (MIA) as a potential serum marker for screening and detection of metastatic uveal melanoma. Design Prospective, clinical study. Material and methods Serum samples of 305 patients with uveal melanoma were collected. Serum samples were analysed by a one-step enzyme-linked immunosorbent assay (ELISA) to quantify the MIA serum levels. All patients underwent a standardized echography of the globe to evaluate maximum tumour height and were checked for systemic metastasis of the tumour by liver enzyme tests and ultrasonography of the liver. Results Twenty patients (6.6%) had proven metastatic disease; eight of them developed it during follow-up. The mean serum concentration of MIA in the 285 patients without metastasis was 6.72 ng/ml, whereas the mean serum concentration of MIA in the 20 patients with metastasis was 13.03 ng/ml (P<0.001). The eight patients who developed metastatic disease during follow-up showed an MIA of 5.92 ng/ml before detection of metastasis and 12.21 ng/ml afterwards (P<0.001). MIA serum levels did neither correlate with the tumour height or to whether local therapy had been applied. Conclusion The elevation of MIA serum levels in patients with metastatic disease from melanoma supports its promising role as a serum marker for monitoring patients with uveal melanoma. The results from this study were presented at the Annual Meeting of the German Society of Ophthalmology (102. Tagung der DOG - Deutsche Ophthalmologische Gesellschaft)     

Age-related decrease of potassium currents in glial (Müller) cells of the human retina

BACKGROUND: Age-dependent alterations have been investigated far less in retinal glial cells than in retinal neurons. We investigated age-dependent alterations of inwardly rectifying potassium (Kir) currents in Müller glial cells of the human retina. METHODS: Müller cells were isolated immediately post mortem from donors without a reported history of eye disease, and the amplitudes of Kir currents and of currents through high-voltage-activated (HVA) calcium channels were measured by whole-cell patch clamping. RESULTS: The amplitude of the Kir currents was lower in the cells from donors older than 50 years than in the cells of younger donors; the decrease was strongly correlated with the donor's age (p < 0.001). The current amplitude in the cells from donors older than 60 years was about 40% lower than the amplitude in the cells from donors younger than 50 years. The amplitude of the HVA currents was greater in the cells from donors older than 55 years than in the cells from younger donors; the increase, up to about 500%, was strongly age-dependent (p < 0.001). INTERPRETATION: The age-related decrease in Kir-current amplitude in Müller cells may reflect the neuron loss in the aged retina. Our findings also indicate that retinal glial cells have enhanced cytoplasmic calcium signals in the course of aging.     

The role of amniotic membrane extract eye drop (AMEED) in in vivo cultivation of limbal stem cells

Background

Limbal stem cell transplantation (LSCT) is the definitive treatment for total limbal stem cell deficiency (LSCD). This study evaluates the anatomical and visual outcomes of a surgical technique supplemented by amniotic membrane extract eye drop (AMEED) for in vivo cultivation of limbal stem cells (LSCs).

Na(+) currents through Ca(2+) channels in human retinal glial (Müller) cells

PURPOSE: To detect the presence of voltage-gated Ca(2+) channels in the plasma membranes of freshly isolated Müller glial cells from the human retina and their modulation by GABA(B) receptor agonists. METHODS: Whole cell voltage-clamp recordings were made to study Ca( 2+), Ba(2+), and Na(+) currents through voltage-gated Ca(2+) channels. RESULTS: The vast majority of the investigated cells displayed no resolvable currents through Ca(2+) channels when Ca(2+) ions (2 mM) were present in the extracellular solution. Small-amplitude inwardly directed currents ( approximately 0.6 pA/pF) were detected when Ba(2+) ions (20 mM) were used as charge carrier. However, when Na(+) ions were used as charge carrier in divalent cation-free external solution, currents of large amplitudes ( approximately 7.5 pA/pF) through voltage-gated Ca(2+) channels were detected. Human Müller cells displayed currents through both transient, low voltage-activated Ca(2+) channels and long-lasting, high voltage-activated channels. The Na(+) fluxes through low voltage-activated Ca( 2+) channels were inhibited in a voltage-independent manner in the presence of GABA(B) receptor agonists. CONCLUSIONS: Human Müller glial cells express different kinds of voltage-gated Ca(2+) channels in their plasma membranes that can be activated only under certain physiological or pathophysiological conditions. The record of Na(+) fluxes in divalent cation-free solutions may be a technique to detect the presence of "hidden" voltage-gated Ca(2+) channels in Müller glial cells.     

Packages of vitreous collagen (type II) in the human retina: an indication of postnatal collagen turnover?

The purpose of this study was to evaluate the vitreoretinal border in the (pre-)equatorial area in nonpathologic human donor eyes, because the majority of retinal defects induced by posterior vitreous detachment (PVD) are located there. Nine eyes (24-80 years) were fixed and embedded in Technovit 8100. After evaluation by light microscope, areas of interest were selected for immunotransmission electron microscope. Anti-type II collagen antibody was used to stain vitreous fibrils and lamellae; anti-type IV collagen antibody was used to identify the internal limiting lamina (ILL); anti-vimentin and anti-CD-68 antibodies stained retinal Muller cells and macrophages, respectively. Observations included fusing of lamellae with the ILL, an intravitreal course of the ILL, and clear focal interruptions in the ILL. In addition, an obvious finding was the presence of intraretinal packages of type II collagen. Interestingly these collagen packages were closely related to Muller cells and, in several eyes, also to macrophages, cell debris and interruptions in the ILL. In our opinion, the collagen packages can reflect the net result of a process of interactive remodelling, in which both breakdown and synthesis of vitreous and ILL collagens take place. Connections between vitreous and intraretinal collagen networks can make the (pre-)equatorial area more vulnerable to tearing and retinal detachment in the case of liquefaction and PVD.     

Arachidonic acid-induced inhibition of Ca2+ channel currents in retinal glial (Müller) cells

BACKGROUND: Arachidonic acid is a second messenger that has been implicated in several pathological conditions in nervous tissues. The present study was carried out to determine whether the second messenger arachidonic acid modulates currents through voltage-gated Ca2+ channels in freshly isolated Müller glial cells. METHODS: Whole-cell voltage-clamp recordings were made in human Muller cells to investigate Ba2+ and Na+ currents through high-voltage-activated (HVA) channels, and in rabbit Muller cells to study Na+ currents through low-voltage-activated (LVA) channels. RESULTS: Extracellular application of arachidonic acid reversibly and dose-dependently depressed the amplitude of both LVA (rabbit cells) and HVA currents (human cells). 10 microM arachidonic acid reduced the peak LVA and HVA currents by approximately 70%. A 50% reduction of LVA currents was achieved at 4.7 microM. The block of HVA and LVA currents was not accompanied by alterations in the voltage dependences of current activation and inactivation. A similar reduction of the currents was achieved by 20 microM eicosatetraynoic acid. CONCLUSION: Since eicosatetraynoic acid mimics the effects of arachidonic acid, it is assumed that arachidonic acid itself rather than its degradation products modulates glial Ca2+ channel activity. This Ca2+ channel inhibition may stabilize Muller cell function during pathological conditions in which arachidonic acid levels are elevated and may participate in the cellular action of neurotransmitters.     

Upregulation of P2X(7) receptor currents in Müller glial cells during proliferative vitreoretinopathy

PURPOSE. Müller glial cells from the human retina express purinergic P2X(7) receptors. Because extracellular adenosine triphosphate (ATP) is assumed to be a mediator of the induction or maintenance of gliosis, this study was undertaken to determine whether the expression of these receptors is different in human Müller cells obtained from retinas of healthy donors and of patients with choroidal melanoma and proliferative vitreoretinopathy (PVR). METHODS. Human Müller cells were enzymatically isolated from donor retinas, and whole-cell patch-clamp recordings were made to characterize the density of the P2X(7) currents and the activation of currents through Ca2+-activated K+ channels of big conductance (I:(BK)) that reflects the increase of the intracellular Ca2+ concentration. RESULTS. Stimulation by external ATP or by benzoylbenzoyl ATP (BzATP) evoked both release of Ca2+ from thapsigargin-sensitive intracellular stores and opening of Ca2+ -permeable P2X(7) channels. These responses caused transient and sustained increases in I:(BK). In Müller cells from patients with PVR, the mean density of the BzATP-evoked cation currents was significantly greater compared with cells from healthy donors. As a consequence, such cells displayed an enlarged I:(BK) during application of purinergic agonists. ATP and BzATP increased the DNA synthesis rate of cultured cells. This effect could be reversed by blocking the I:(BK). CONCLUSIONS. The increased density of P2X(7) receptor channels may permit a higher level of entry of extracellular Ca2+ into cells from patients with PVR. Enhanced Ca2+ entry and the subsequent stronger activation of I:(BK) may contribute to the induction or maintenance of proliferative activity in gliotic Müller cells during PVR.     

TNF-α inhibitor tanfanercept (HBM9036) improves signs and symptoms of dry eye in a phase 2 trial in the controlled adverse environment in China

International Ophthalmology - This study evaluated the clinical safety and efficacy of tanfanercept (HBM9036) ophthalmic solution as a novel treatment for dry eye disease (DED) in a controlled...     

Minor influence of the immunosuppressive cytokines IL-10 and TGF-ß on the proliferation and apoptosis of human retinal pigment epithelial (RPE) cells in vitro

Undesirable immune reactions such as uveitis or graft rejection after corneal and subretinal transplantations are serious inflammations in the eye. Minimizing this process by means of physiological suppressors, either through systemic or intraocular administration with or without gene therapy, is a future therapeutic possibility. In our study, we used different concentrations of transforming growth factor-ß (TGF-ß; 5, 10, and 50 ng/ml) and interleukin-10 (IL-10; 100, 200, and 500 U/ml), both known as modulators of the suppression process, to treat human retinal pigment epithelium (RPE) cells in vitro. The influence of both cytokines on the viability and proliferation of the RPE cells was measured. Furthermore, the secretion of typical markers of the apoptosis process, such as Fas, soluble Fas ligand, and bcl-2, was investigated. Our results show that the concentrations of TGF-ß and IL-10 used have only a slight influence on RPE cells. Cell proliferation under the influence of TGF-ß was significantly reduced, whereas more Fas protein could be found in the cell lysate of the IL-10 samples. In general, IL-10 seemed to have less effect on the physiology of RPE cells. The discussion of the therapeutic use of an immunosuppressive factor in the eye should therefore be focused more on this cytokine.     

Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) – Report 2: Pattern of Uveitis Investigations in Singapore

ABSTRACT

Purpose: To analyze the pattern of laboratory investigations of uveitis at a tertiary referral eye care center in Singapore.

Methods: Retrospective analysis of 2040 uveitis cases from the Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) database over a 12-year period (2004 – 2015).

Results: Patients with retinal vasculitis (RV) had the most tests utilized per patient (6.79), followed by intermediate uveitis (IU) (5.25), panuveitis (Pan) (5.12), posterior uveitis (PU) (4.17), anterior uveitis (AU) (2.75), and keratouveitis (KU) (1.10). The most frequently utilized test for infective etiology were the VDRL (41.3%), Syphilis IgG (29.5%), and T-SPOT.TB (24.6%). For autoimmune tests, ANA was most utilized (18.2%), followed by anti-dsDNA (14.8%), and HLA-B27 (12.4%).

Conclusion: There was high utilization of autoimmune tests such as ANA, anti-dsDNA, RF, and ANCA, despite its limited yield. Rationalization of investigations in patients with ocular inflammation via a stepladder approach may help optimize the use of limited resources.