Retinal pigment epithelium tears after intravitreal injection of ranibizumab for predominantly classic neovascular membranes secondary to age-related macular degeneration.

PURPOSE: Retinal pigment epithelium (RPE) tear is an extremely rare complication in patients with classic neovascular membranes without RPE detachment. We evaluate their incidence and functional outcome following treatment with intravitreal ranibizumab. METHODS: Observational study of 72 consecutive patients (74 eyes) treated at Jules Gonin University Eye Hospital, Lausanne, with intravitreal ranibizumab 0.5 mg for classic choroidal neovascularization (CNV) between March 2006 and February 2008. Best-corrected visual acuity (BCVA), fundus examination and optical coherence tomography were recorded monthly; fluorescein angiography was performed at baseline and repeated at least every 3 months. RESULTS: RPE tears occurred in four (5.4%) eyes temporal to the fovea, after a mean of four injections (range 3-6). Mean baseline BCVA was 0.25 decimal equivalent (logMAR 0.67) and improved despite the RPE tear to 0.6 decimal equivalent (logMAR 0.22). CONCLUSION: RPE tears following intravitreal ranibizumab injections for classic CNV can occur in about 5% of patients, even in the absence of baseline RPE detachment. Nevertheless, vision may improve provided the fovea is not involved.

Transport of methotrexate by the in vitro isolated rabbit proximal tubule.

The tubular transport of [3H]methotrexate was studied in isolated nonperfused and perfused superficial proximal tubular segments of rabbit kidneys. Reabsorption represented only 5% of perfused methotrexate, and appeared to be mostly of passive nature inasmuch as it was not modified by reducing the temperature or by ouabain. Cellular accumulation in nonperfused segments and secretion in perfused tubules were highest in the S2 segment and lower in the S3 and S1 segments. Secretion against a bath-to-lumen concentration gradient was observed only in S2 segments (with a maximum methotrexate secretory rate of 478 +/- 48 fmol/mm.min and an apparent Km of transport of 363 +/- 32 microM), and was inhibited by probenecid and folate. The low capacity for methotrexate secretion may be explained by a low capacity of transport across the basolateral membrane of the proximal cell as methotrexate was accumulated only to a low extent in nonperfused tubules (tissue water to medium concentration ratio of 8.2 +/- 1 in S2 segments). During secretion a small amount of methotrexate was metabolized; the nature of the metabolite(s) remains to be defined.

Sodium and potassium balance depends on αENaC expression in connecting tubule.

Mutations in α, β, or γ subunits of the epithelial sodium channel (ENaC) can downregulate ENaC activity and cause a severe salt-losing syndrome with hyperkalemia and metabolic acidosis, designated pseudohypoaldosteronism type 1 in humans. In contrast, mice with selective inactivation of αENaC in the collecting duct (CD) maintain sodium and potassium balance, suggesting that the late distal convoluted tubule (DCT2) and/or the connecting tubule (CNT) participates in sodium homeostasis. To investigate the relative importance of ENaC-mediated sodium absorption in the CNT, we used Cre-lox technology to generate mice lacking αENaC in the aquaporin 2-expressing CNT and CD. Western blot analysis of microdissected cortical CD (CCD) and CNT revealed absence of αENaC in the CCD and weak αENaC expression in the CNT. These mice exhibited a significantly higher urinary sodium excretion, a lower urine osmolality, and an increased urine volume compared with control mice. Furthermore, serum sodium was lower and potassium levels were higher in the genetically modified mice. With dietary sodium restriction, these mice experienced significant weight loss, increased urinary sodium excretion, and hyperkalemia. Plasma aldosterone levels were significantly elevated under both standard and sodium-restricted diets. In summary, αENaC expression within the CNT/CD is crucial for sodium and potassium homeostasis and causes signs and symptoms of pseudohypoaldosteronism type 1 if missing.

The retinoid-related orphan receptor RORα promotes keratinocyte differentiation via FOXN1.

RORα is a retinoid-related orphan nuclear receptor that regulates inflammation, lipid metabolism, and cellular differentiation of several non-epithelial tissues. In spite of its high expression in skin epithelium, its functions in this tissue remain unclear. Using gain- and loss-of-function approaches to alter RORα gene expression in human keratinocytes (HKCs), we have found that this transcription factor functions as a regulator of epidermal differentiation. Among the 4 RORα isoforms, RORα4 is prominently expressed by keratinocytes in a manner that increases with differentiation. In contrast, RORα levels are significantly lower in skin squamous cell carcinoma tumors (SCCs) and cell lines. Increasing the levels of RORα4 in HKCs enhanced the expression of structural proteins associated with early and late differentiation, as well as genes involved in lipid barrier formation. Gene silencing of RORα impaired the ability of keratinocytes to differentiate in an in vivo epidermal cyst model. The pro-differentiation function of RORα is mediated at least in part by FOXN1, a well-known pro-differentiation transcription factor that we establish as a novel direct target of RORα in keratinocytes. Our results point to RORα as a novel node in the keratinocyte differentiation network and further suggest that the identification of RORα ligands may prove useful for treating skin disorders that are associated with abnormal keratinocyte differentiation, including cancer.

Distribution of the human intracellular serpin protease inhibitor 8 in human tissues.

Ovalbumin-like serine protease inhibitors are mainly localized intracellularly and their in vivo functions are largely unknown. To elucidate their physiological role(s), we studied the expression of one of these inhibitors, protease inhibitor 8 (PI-8), in normal human tissues by immunohistochemistry using a PI-8-specific monoclonal antibody. PI-8 was strongly expressed in the nuclei of squamous epithelium of mouth, pharynx, esophagus, and epidermis, and by the epithelial layer of skin appendages, particularly by more differentiated epithelial cells. PI-8 was also expressed by monocytes and by neuroendocrine cells in the pituitary gland, pancreas, and digestive tract. Monocytes showed nuclear and cytoplasmic localization of PI-8, whereas neuroendocrine cells showed only cytoplasmic staining. In vitro nuclear localization of PI-8 was confirmed by confocal analysis using serpin-transfected HeLa cells. Furthermore, mutation of the P(1) residue did not affect the subcellular distribution pattern of PI-8, indicating that its nuclear localization is independent of the interaction with its target protease. We conclude that PI-8 has a unique distribution pattern in human tissues compared to the distribution patterns of other intracellular serpins. Additional studies must be performed to elucidate its physiological role.

Loss of Cutaneous TSLP-Dependent Immune Responses Skews the Balance of Inflammation from Tumor Protective to Tumor Promoting.

Inflammation can promote or inhibit cancer progression. In this study we have addressed the role of the proinflammatory cytokine thymic stromal lymphopoietin (TSLP) during skin carcinogenesis. Using conditional loss- and gain-of-function mouse models for Notch and Wnt signaling, respectively, we demonstrate that TSLP-mediated inflammation protects against cutaneous carcinogenesis by acting directly on CD4 and CD8 T cells. Genetic ablation of TSLP receptor (TSLPR) perturbs T-cell-mediated protection and results in the accumulation of CD11b(+)Gr1(+) myeloid cells. These promote tumor growth by secreting Wnt ligands and augmenting β-catenin signaling in the neighboring epithelium. Epithelial specific ablation of β-catenin prevents both carcinogenesis and the accumulation of CD11b(+)Gr1(+) myeloid cells, suggesting tumor cells initiate a feed-forward loop that induces protumorigenic inflammation.

Monocyte differentiation toward regulatory dendritic cells is not affected by respiratory syncytial virus-induced inflammatory mediators.

Airway epithelial cells were shown to drive the differentiation of monocytes into dendritic cells (DCs) with a suppressive phenotype. In this study, we investigated the impact of virus-induced inflammatory mediator production on the development of DCs. Monocyte differentiation into functional DCs, as reflected by the expression of CD11c, CD123, BDCA-4, and DC-SIGN and the capacity to activate T cells, was similar for respiratory syncytial virus (RSV)-infected and mock-infected BEAS-2B and A549 cells. RSV-conditioned culture media resulted in a partially mature DC phenotype, but failed to up-regulate CD80, CD83, CD86, and CCR7, and failed to release proinflammatory mediators upon Toll-like receptor (TLR) triggering. Nevertheless, these DCs were able to maintain an antiviral response by the release of Type I IFN. Collectively, these data indicate that the airway epithelium maintains an important suppressive DC phenotype under the inflammatory conditions induced by infection with RSV.

IB1/JIP-1 controls JNK activation and increased during prostatic LNCaP cells neuroendocrine differentiation.

The scaffold protein Islet-Brain1/c-Jun amino-terminal kinase Interacting Protein-1 (IB1/JIP-1) is a modulator of the c-Jun N-terminal kinase (JNK) activity, which has been implicated in pleiotrophic cellular functions including cell differentiation, division, and death. In this study, we described the presence of IB1/JIP-1 in epithelium of the rat prostate as well as in the human prostatic LNCaP cells. We investigated the functional role of IB1/JIP-1 in LNCaP cells exposed to the proapoptotic agent N-(4-hydroxyphenyl)retinamide (4-HPR) which induced a reduction of IB1/JIP-1 content and a concomittant increase in JNK activity. Conversely, IB1/JIP-1 overexpression using a viral gene transfer prevented the JNK activation and the 4-HPR-induced apoptosis was blunted. In prostatic adenocarcinoma cells, the neuroendocrine (NE) phenotype acquisition is associated with tumor progression and androgen independence. During NE transdifferentiation of LNCaP cells, IB1/JIP-1 levels were increased. This regulated expression of IB1/JIP-1 is secondary to a loss of the neuronal transcriptional repressor neuron restrictive silencing factor (NRSF/REST) function which is known to repress IB1/JIP-1. Together, these results indicated that IB1/JIP-1 participates to the neuronal phenotype of the human LNCaP cells and is a regulator of JNK signaling pathway.

Expression of SCG10 and stathmin proteins in the rat olfactory system during development and axonal regeneration.

The membrane-associated protein SCG10 is expressed specifically by neuronal cells. Recent experiments have suggested that it promotes neurite outgrowth by increasing microtubule dynamics in growth cones. SCG10 is related to the ubiquitous but neuron-enriched cytosolic protein stathmin. To better understand the role played by SCG10 and stathmin in vivo, we have analyzed the expression and localization of these proteins in both the olfactory epithelium and the olfactory bulb in developing and adult rats, as well as in adult bulbectomized rats. The olfactory epithelium is exceptional in that olfactory receptor neurons constantly regenerate and reinnervate the olfactory bulb throughout animal life-span. SCG10 and stathmin expression in the olfactory receptor neurons was found to be regulated during embryonic and postnatal development and to correlate with neuronal maturation. Whereas SCG10 expression was restricted to immature olfactory receptor neurons (GAP-43-positive, olfactory marker protein-negative), stathmin was also expressed by the basal cells. In the olfactory bulb of postnatal and adult rats, a moderate to strong SCG10 immunoreactivity was present in the olfactory nerve layer, whereas no labeling was detected in the glomerular layer. Olfactory glomeruli also showed no apparent immunoreactivity for several cytoskeletal proteins such as tubulin and microtubule-associated proteins. In unilaterally bulbectomized rats, SCG10 and stathmin were seen to be up-regulated in the regenerating olfactory epithelium at postsurgery stages corresponding to olfactory axon regeneration. Our data strongly suggest that, in vivo, both SCG10 and stathmin may play a role in axonal outgrowth during ontogenesis as well as during axonal regeneration.

Images in clinical urology. Nail of glans penis.

A 56-year-old man presented with a "nail" growing at the base of his glans penis. The tumor was locally excised, and microscopic examination revealed papillomatosis and hyperkeratosis of the malpighian epithelium, with a strong inflammatory reaction of the chorion and signs of local microinvasion, as well as the presence of well-differentiated squamous epithelial cells. The surgical margins were negative. The differential diagnosis was made between a benign papillomatous proliferation and verrucous carcinoma.

Autofluorescence Findings Of A Novel Maculopathy In Patient With Spinocerebellar Ataxia Type 1 And Of A Cone - Rod Type Retinal Dysfunction In Three Generation Family With Spinocerebellar Ataxia Type 7

Purpose: To report a novel maculopathy in a patient with SCA1. To describe autofluorescence findings in family with SCA7 and associated cone-rod retinal dysfunction.Methods: 4 affected patients from two families were assessed to investigate a progressive loss of visual acuity (VA). Examinations included fundus photography, autofluorescence (AF) fundus fluorescein angiogragraphy (FFA) and optical coherence tomography. Electroretinogram (full-field) was performed in 2 affected patients. All patients had color vision testing using Ishihara pseudoisochromatic plates. Molecular analysis was performed in family 2.Results: The patient with known diagnosis of SCA1 had a visual acuity of 20/200 bilaterally and dyschromatopsia. He had saccadic pursuit. Fundus examination showed mild retinal pigment epithelium (RPE) changes at the macula. OCT showed bilateral macular serous detachment, which was not obvious at the FFA and explained his VA. AF imaging showed a central hyperfluorescence. The 45 year old proband from family 2 had a visual acuity of 200/20 and dyschromatopsia. ERG testing showed cone type dysfunction of photoreceptors. Her daughter affected at a younger age had the same ERGs findings. Fundus examination showed mild RPE changes in proband, normal findings in her daughter. AF imaging of both patients showed a ring of high density AF around the fovea. The ring was also obvious on near infrared AF. Later onset of gait imbalance led to the diagnosis of SCA7Conclusions: Within the group of spinocerebellar ataxias, only the type 7 is associated with retinal dysfunction. We present the first report of maculopathy associated with SCA1 causing severe vision loss. The ring of high density AF in SCA7 confirmed an early retinal photoreceptor dysfunction in patient with normal fundus.

MFGE8 does not influence chorio-retinal homeostasis or choroidal neovascularization in vivo.

PURPOSE: Milk fat globule-epidermal growth factor-factor VIII (MFGE8) is necessary for diurnal outer segment phagocytosis and promotes VEGF-dependent neovascularization. The prevalence of two single nucleotide polymorphisms (SNP) in MFGE8 was studied in two exsudative or "wet" Age-related Macular Degeneration (AMD) groups and two corresponding control groups. We studied the effect of MFGE8 deficiency on retinal homeostasis with age and on choroidal neovascularization (CNV) in mice. METHODS: The distribution of the SNP (rs4945 and rs1878326) of MFGE8 was analyzed in two groups of patients with "wet" AMD and their age-matched controls from Germany and France. MFGE8-expressing cells were identified in Mfge8(+/-) mice expressing ß-galactosidase. Aged Mfge8(+/-) and Mfge8(-/-) mice were studied by funduscopy, histology, electron microscopy, scanning electron microscopy of vascular corrosion casts of the choroid, and after laser-induced CNV. RESULTS: rs1878326 was associated with AMD in the French and German group. The Mfge8 promoter is highly active in photoreceptors but not in retinal pigment epithelium cells. Mfge8(-/-) mice did not differ from controls in terms of fundus appearance, photoreceptor cell layers, choroidal architecture or laser-induced CNV. In contrast, the Bruch's membrane (BM) was slightly but significantly thicker in Mfge8(-/-) mice as compared to controls. CONCLUSIONS: Despite a reproducible minor increase of rs1878326 in AMD patients and a very modest increase in BM in Mfge8(-/-) mice, our data suggests that MFGE8 dysfunction does not play a critical role in the pathogenesis of AMD.

Secretory IgA's complex roles in immunity and mucosal homeostasis in the gut.

Secretory IgA (SIgA) serves as the first line of defense in protecting the intestinal epithelium from enteric toxins and pathogenic microorganisms. Through a process known as immune exclusion, SIgA promotes the clearance of antigens and pathogenic microorganisms from the intestinal lumen by blocking their access to epithelial receptors, entrapping them in mucus, and facilitating their removal by peristaltic and mucociliary activities. In addition, SIgA functions in mucosal immunity and intestinal homeostasis through mechanisms that have only recently been revealed. In just the past several years, SIgA has been identified as having the capacity to directly quench bacterial virulence factors, influence composition of the intestinal microbiota by Fab-dependent and Fab-independent mechanisms, promote retro-transport of antigens across the intestinal epithelium to dendritic cell subsets in gut-associated lymphoid tissue, and, finally, to downregulate proinflammatory responses normally associated with the uptake of highly pathogenic bacteria and potentially allergenic antigens. This review summarizes the intrinsic biological activities now associated with SIgA and their relationships with immunity and intestinal homeostasis.

Airway surface liquid volume regulation determines different airway phenotypes in liddle compared with betaENaC-overexpressing mice.

Studies in cystic fibrosis patients and mice overexpressing the epithelial Na(+) channel beta-subunit (betaENaC-Tg) suggest that raised airway Na(+) transport and airway surface liquid (ASL) depletion are central to the pathogenesis of cystic fibrosis lung disease. However, patients or mice with Liddle gain-of-function betaENaC mutations exhibit hypertension but no lung disease. To investigate this apparent paradox, we compared the airway phenotype (nasal versus tracheal) of Liddle with CFTR-null, betaENaC-Tg, and double mutant mice. In mouse nasal epithelium, the region that functionally mimics human airways, high levels of CFTR expression inhibited Liddle epithelial Nat channel (ENaC) hyperfunction. Conversely, in mouse trachea, low levels of CFTR failed to suppress Liddle ENaC hyperfunction. Indeed, Na(+) transport measured in Ussing chambers ("flooded" conditions) was raised in both Liddle and betaENaC-Tg mice. Because enhanced Na(+) transport did not correlate with lung disease in these mutant mice, measurements in tracheal cultures under physiologic "thin film" conditions and in vivo were performed. Regulation of ASL volume and ENaC-mediated Na(+) absorption were intact in Liddle but defective in betaENaC-Tg mice. We conclude that the capacity to regulate Na(+) transport and ASL volume, not absolute Na(+) transport rates in Ussing chambers, is the key physiologic function protecting airways from dehydration-induced lung disease.