Mina Massaro-Giordano

Iron homeostasis and toxicity in retinal degeneration

Iron is essential for many metabolic processes but can also cause damage. As a potent generator of hydroxyl radical, the most reactive of the free radicals, iron can cause considerable oxidative stress. Since iron is absorbed through diet but not excreted except through menstruation, total body iron levels buildup with age. Macular iron levels increase with age, in both men and women. This iron has the potential to contribute to retinal degeneration. Here we present an overview of the evidence suggesting that iron may contribute to retinal degenerations. Intraocular iron foreign bodies cause retinal degeneration. Retinal iron buildup resulting from hereditary iron homeostasis disorders aceruloplasminemia, Friedreichs ataxia, and panthothenate kinase-associated neurodegeneration cause retinal degeneration. Mice with targeted mutation of the iron exporter ceruloplasmin have age-dependent retinal iron overload and a resulting retinal degeneration with features of age-related macular degeneration (AMD). Post mortem retinas from patients with AMD have more iron and the iron carrier transferrin than age-matched controls. Over the past 10 years much has been learned about the intricate network of proteins involved in iron handling. Many of these, including transferrin, transferrin receptor, divalent metal transporter-1, ferritin, ferroportin, ceruloplasmin, hephaestin, iron-regulatory protein, and histocompatibility leukocyte antigen class I-like protein involved in iron homeostasis (HFE) have been found in the retina. Some of these proteins have been found in the cornea and lens as well. Levels of the iron carrier transferrin are high in the aqueous and vitreous humors. The functions of these proteins in other tissues, combined with studies on cultured ocular tissues, genetically engineered mice, and eye exams on patients with hereditary iron diseases provide clues regarding their ocular functions. Iron may play a role in a broad range of ocular diseases, including glaucoma, cataract, AMD, and conditions causing intraocular hemorrhage. While iron deficiency must be prevented, the therapeutic potential of limiting iron-induced ocular oxidative damage is high. Systemic, local, or topical iron chelation with an expanding repertoire of drugs has clinical potential.

Amniotic membrane transplantation in ocular surface disorders

Chronic ocular surface disorders, which can result in severe functional impairment, have been viewed for decades as untreatable diseases. In 1995, the reintroduction of amniotic membrane transplantation (AMT), either alone or associated with limbal stem cell transplantation, has offered new hope of using tissue and cell therapy strategies to repair ocular surface disorders. Amniotic membrane (AM) has been found to exert its effects by acting as a substrate for the growth of ocular surface epithelia, by suppressing inflammation and scarring and by serving as an anti‐microbial barrier. Moreover, AM has recently been used as a substrate for ex vivo expansion of corneal epithelial cells for ocular surface reconstruction. Notwithstanding the substantial agreement among Authors regarding its clinical efficacy, there are still many uncertainties regarding the fate of grafted AM and consequently the mechanisms through which it exerts its long‐term effects. Further studies including controlled clinical trials with numerous cases are required to understand which ocular surface conditions are certain to benefit from AM transplantation and how its mechanical properties interact with the mediators produced to favor ocular surface reconstruction.

The cellular mechanisms of dry eye: From pathogenesis to treatment

Dry eye is a complex disease characterized by changes in the ocular surface epithelia related to reduced quality and/or quantity of tears, inflammatory reaction, and impairment of ocular surface sensitivity. It has recently been proposed that increased tear osmolarity represents a main trigger to the altered cellular mechanisms leading to epithelial damage in dry eye. However, dry eye pathogenesis is multifactorial, with cytotoxic inflammatory mediators, altered lacrimal gland secretion and nerve function, squamous metaplasia of the conjunctival epithelium and decrease of goblet cells density, all playing a role in a detrimental loop that perpetuates and worsens damage to the corneal and conjunctival epithelia. Current topical treatments for dry eye patients include the use of lubricants and anti‐inflammatory drugs. However, lubricants only improve symptoms temporarily, and chronic use of topical steroids is associated to severe ocular side effects such as cataract and glaucoma. The deeper understanding of the cellular mechanisms that are altered in dry eye is opening novel perspectives for patients and physicians, who are seeking treatments capable not only of improving symptoms but also of restoring the homeostasis of the ocular surface. In this review, we will focus on novel anti‐inflammatory agents and on nerve growth factor, a neurotrophin that is altered in dry eye and has been suggested as a main player in the neuroimmune cross‐talk of the ocular surface as well as in the stimulation of corneal sensitivity, epithelial proliferation and differentiation, and stimulation of mucin production by goblet cells. J. Cell. Physiol. 228: 2253–2256, 2013.

Variability of Tear Osmolarity in Patients With Dry Eye

IMPORTANCE Knowledge about the variability of measurements using the TearLab Osmolarity System is necessary when evaluating the clinical utility of readings. OBJECTIVE To examine the variability of tear osmolarity measured by the TearLab Osmolarity System in patients with Sjögren syndrome (SS), patients with blepharitis, and control participants. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study at a tertiary care academic center from June 13, 2012, to March 21, 2013. Participants included 74 eyes of 37 patients from a volunteer sample (18 patients with SS, 11 patients with blepharitis, and 8 control participants) who were evaluated using the TearLab Osmolarity System, with 3 consecutive osmolarity measurements taken at 1-minute intervals in a session; 15 of these patients had the same measurements taken by the same examiner in 2 additional sessions on the same day (9 AM-10 AM, 12 PM-1 PM, or 3 PM-4 PM). Most patients with SS and patients with blepharitis were taking systemic or topical dry eye medications at the time of enrollment. MAIN OUTCOMES AND MEASURES Mean osmolarity and its variability calculated from a linear mixed model for each disease group that accounts for the variations attributable to different patients, eyes, and sessions and measurement error specific to each disease group. RESULTS Mean tear osmolarity was 307 mOsm/L, 304 mOsm/L, and 301 mOsm/L in the SS, blepharitis, and control groups, respectively (P = .46). The error associated with repeated measurements within a session in the patients without dry eye (10.5 mOsm/L [95% CI, 9.0-12.4]) was significantly lower than in the patients with blepharitis (14.6 mOsm/L [95% CI, 12.5-17.5]; P = .006) and patients with SS (15.8 mOsm/L [95% CI, 14.2-17.8]; P < .001) but a difference in the error of repeated measurements between patients with blepharitis and patients with SS was not identified (P = .46). CONCLUSIONS AND RELEVANCE There was increased variability attributable to error in repeated measurements in patients with SS and patients with blepharitis compared with control participants. The high variability of TearLab osmolarity readings in all groups makes the clinical interpretation of measurements unclear.

Genetic and epigenetic alterations of RB2/p130 tumor suppressor gene in human sporadic retinoblastoma: implications for pathogenesis and therapeutic approach.

Human retinoblastoma occurs in two forms (familial and sporadic) both due to biallelic mutation of the RB1/p105 gene even if its loss is insufficient for malignancy. We have recently reported that loss of expression of the retinoblastoma-related protein pRb2/p130 correlates with low apoptotic index, suggesting that RB2/p130 gene could be involved in retinoblastoma. Mutational analysis of RB2/p130 in primary tumors showed a tight correlation between Exon 1 mutations and pRb2/p130 expression level in sporadic retinoblastoma. These mutations are located within a CpG-enriched region prone to de novo methylation. Analysis of RB2/p130 methylation status revealed that epigenetic events, most probably consequent to the Exon 1 mutations, determined the observed phenotype. Treatment of Weri-Rb1 cell line by 5-Aza-dC induced an increase in expression level of pRb2/p130, E2F1, p73 and p53. Overall, our results highlight a crucial role of epigenetic events in sporadic retinoblastoma, which opens a perspective for new therapeutic approaches.

Bilateral optic nerve infiltration in central nervous system leukemia

PURPOSE To report the case of a 58-year-old man with sequential bilateral retrolaminar leukemic infiltration of the optic nerves who presented with normal-appearing optic nerves and no optic nerve enhancement. DESIGN Interventional case report. METHODS A 58-year-old man with chronic myelogenous leukemia (CML) developed progressive vision loss to no light perception in both eyes over four days. The patient received 14 doses of external beam irradiation and 10 cycles of intrathecal cytarabine. Despite treatment, he developed optic nerve pallor, and visual acuity remained no light perception in both eyes. CONCLUSIONS In a patient with leukemia, leukemic optic nerve infiltration may occur even with normal-appearing optic nerves and a normal magnetic resonance image. It is important to maintain a high clinical suspicion for optic nerve infiltration so that prompt local irradiation may be initiated.

Amniotic membrane graft: Histopathological findings in five cases

Amniotic membrane transplantation (AMT) is an effective treatment for ocular surface reconstruction; however, the mechanisms through which amniotic membrane (AM) exerts its effects as well as its fate after transplantation have not been entirely elucidated and have been investigated only in part. We evaluate the integration of AM in the host cornea in five patients who underwent AMT as the result of Bowens disease, band keratopathy, radio‐ or cryotherapy‐induced keratopathy, chemical burn or post‐herpetic deep corneal ulcer with descemetocele. Due to persistent opacification in four cases and a progressing tumor in one case, penetrating keratoplasty (PK) and enucleation were performed as early as 2 months and up to 20 months after AMT. The corneas were analyzed histopathologically. To evaluate AM remnants, corneas were stained with periodic acid Schiffs reaction (PAS), Alcian blue, and Gomory and Masson trichrome; immunostaining including collagens III and IV antibodies was also performed. None of the corneas showed remnants of AM. In all cases, we observed discontinuity of Bowmans membrane. In three cases, the corneal epithelium was completely restored, ranging from three to six cell layers. In the other two cases, we detected an intense inflammatory reaction with rich neovascularization; the epithelial surface of the central cornea was completely restored, while at the periphery of the cornea goblet mucus‐producing cells were present. Although clinically useful in all cases, restoration of a stable corneal epithelium through AMT is limited by the extent and severity of limbal stem cell deficiency (LSCD). The lack of histologically documented AM remnants in our cases seems to explain the efficacy of AMT more through its biological properties than through its mechanical properties.

The SSB-positive/SSA-negative antibody profile is not associated with key phenotypic features of Sjögren's syndrome

Objective To determine whether the Sjögrens syndrome B (SSB)-positive/Sjögrens syndrome A (SSA)-negative antibody profile is associated with key phenotypic features of SS. Methods Among registrants in the Sjögrens International Collaborative Clinical Alliance (SICCA) with possible or established SS, we compared anti-SSA/anti-SSB reactivity profiles against concurrent phenotypic features. We fitted logistic regression models to explore the association between anti-SSA/anti-SSB reactivity profile and each key SS phenotypic feature, controlling for potential confounders. Results Among 3297 participants, 2061 (63%) had negative anti-SSA/anti-SSB, 1162 (35%) had anti-SSA with or without anti-SSB, and 74 (2%) anti-SSB alone. Key SS phenotypic features were more prevalent and had measures indicative of greater disease activity in those participants with anti-SSA, either alone or with anti-SSB, than in those with anti-SSB alone or negative SSA/SSB serology. These between-group differences were highly significant and not explained by confounding by age, race/ethnicity or gender. Participants with anti-SSB alone were comparable to those with negative SSA/SSB serology in their association with these key phenotypic features. Among SICCA participants classified with SS on the basis of the American-European Consensus Group or American College of Rheumatology criteria, only 2% required the anti-SSB-alone test result to meet these criteria. Conclusions The presence of anti-SSB, without anti-SSA antibodies, had no significant association with SS phenotypic features, relative to seronegative participants. The solitary presence of anti-SSB antibodies does not provide any more support than negative serology for the diagnosis of SS. This serological profile should thus be interpreted cautiously in clinical practice and potentially eliminated from future classification criteria.

Tear osmolarity and dry eye symptoms in diabetics

Purpose To assess the relationship between tear osmolarity and dry eye symptoms in patients with diabetes. Patients and methods Fifty patients with diabetes were enrolled. Demographic information and past medical history were recorded. Symptoms were assessed using the ocular surface disease index (OSDI). Tear osmolarity of each eye was measured with the TearLab® Osmolarity System. Results The majority of the subjects were female (76%), African American (56%), and/or had a diagnosis of type 2 diabetes (82%). The mean ± standard deviation (SD) for age was 54.6±13.4, and maximum tear osmolarity was 304.6±12.7 mOsm/L. Men had higher osmolarity than women (mean ± standard error (SE) 311.8±4.0 mOsm/L versus 302.3±1.9 mOsm/L, P=0.02). Age, race, use of artificial tears, years of diabetes, and hemoglobin A1c did not have a statistically significant association with tear osmolarity. Longer duration of diabetes was associated with lower (less severe) OSDI scores (r=−0.35, P=0.01). Higher tear osmolarity was associated with lower (less severe) OSDI scores (r=−0.29, P=0.04). Conclusion Approximately half of the diabetic subjects in our study had elevated tear osmolarity, and half of our population also reported symptoms consistent with dry eye disease. However, the two were slightly inversely related in that those with higher osmolarity reported fewer symptoms. Subjects with a longer duration of diabetes also reported fewer dry eye symptoms. Therefore, health care providers should be aware that patients who are most likely to have ocular surface disease, including those with long-standing diabetes, may not experience symptoms and seek care in a timely manner.

Blood derived stem cells: an ameliorative therapy in veterinary ophthalmology.

Stem cell technology has evoked considerable excitement among people interested in the welfare of animals, as it has suggested the potential availability of new tools for several pathologies, including eye disease, which in many cases is considered incurable. One such example is ulcerative keratitis, which is very frequent in horses. Because some of these corneal ulcers can be very severe, progress rapidly and, therefore, can be a possible cause of vision loss, it is important to diagnose them at an early stage and administer an appropriate treatment, which can be medical, surgical, or a combination of both. The therapeutic strategy should eradicate the infection in order to reduce or stop destruction of the cornea. In addition, it should support the corneal structures and control the uveal reaction, and the pain associated with it, in order to minimize scarring. In this study, we address how stem cells derived from peripheral blood can be used also in ophthalmological pathologies. Our results demonstrate that this treatment protocol improved eye disease in four horse cases, including corneal ulcers and one case of retinal detachment. In all cases, we detected a decrease in the intense inflammatory reaction as well as the restoration of the epithelial surface of the central cornea. J. Cell. Physiol. 227: 1250–1256, 2012.