A tryptophan metabolite prevents depletion of circulating endothelial progenitor cells in systemic low-grade inflammation

Background

Chronic systemic inflammation reduces the bioavailability of circulating endothelial progenitor cells (EPCs). Indoleamine 2,3-dioxygenase 1 (IDO1), a key enzyme of immune tolerance catalyzing the initial step of tryptophan degradation along the so-called l-kynurenine (l-kyn) pathway, that is induced by inflammatory stimuli and exerts anti-inflammatory effects. A specific relationship between IDO1 activity and circulating EPC numbers has not yet been investigated.

Methods

In this study, circulating EPCs were examined in mice treated with low doses of lipopolysaccharide (LPS) to mimic low-grade inflammation. Moreover, the association between IDO1 activity and circulating EPCs was studied in a cohort of 277 patients with variable systemic low-grade inflammation.

Results

Repeated low doses of LPS caused a decrease in circulating EPCs and l-kyn supplementation, mimicking IDO1 activation, significantly increased EPC numbers under homeostatic conditions preventing EPC decline in low-grade endotoxemia. Accordingly, in patients with variable systemic low-grade inflammation, there was a significant interaction between IDO1 activity and high-sensitivity C-reactive protein (hs-CRP) in predicting circulating EPCs, with high hs-CRP associated with significantly lower EPCs at low IDO1 activity but not at high IDO1 activity.

Interpretation

Overall, these findings demonstrate that systemic low-grade inflammation reduces circulating EPCs. However, high IDO1 activity and l-kyn supplementation limit circulating EPC loss in low-grade inflammation.

Microbiota-Associated HAF-EVs Regulate Monocytes by Triggering or Inhibiting Inflammasome Activation

In pregnancy, human amniotic fluid extracellular vesicles (HAF-EVs) exert anti-inflammatory effects on T cells and on monocytes, supporting their immunoregulatory roles. The specific mechanisms are still not completely defined. The aim of this study was to investigate the ability of HAF-EVs, isolated from pregnant women who underwent amniocentesis and purified by gradient ultracentrifugation, to affect inflammasome activation in the human monocytes. Proteomic studies revealed that HAF-EV samples expressed several immunoregulatory molecules as well as small amounts of endotoxin. Surprisingly, metagenomic analysis shows the presence of specific bacterial strain variants associated with HAF-EVs as potential sources of the endotoxin. Remarkably, we showed that a single treatment of THP-1 cells with HAF-EVs triggered inflammasome activation, whereas the same treatment followed by LPS and ATP sensitization prevented inflammasome activation, a pathway resembling monocyte refractories. A bioinformatics analysis of microbiota-HAF-EVs functional pathways confirmed the presence of enzymes for endotoxin biosynthesis as well as others associated with immunoregulatory functions. Overall, these data suggest that HAF-EVs could serve as a source of the isolation of a specific microbiota during early pregnancy. Moreover, HAF-EVs could act as a novel system to balance immune training and tolerance by modulating the inflammasome in monocytes or other cells.

Endotoxin-Tolerance Mimicking to Study TLR in Promotion of Tolerogenic DCs and Tr1 Cells

Dendritic cells (DCs) are key regulators of immunogenic and tolerogenic immune responses. Both these immune responses require DCs respectively to activate effector T cells or to induce their anergy and T regulatory activity. Modifications of DCs in the laboratory and several pharmacological agents can enhance and stabilize their tolerogenic properties. Recent evidences demonstrate that activation of specific toll-like receptors (TLRs) can be involved in induction of DCs with tolerogenic properties able to initiate T regulatory cell responses.In the present chapter, we show a detail protocol to obtain in vitro regulatory conventional DCs (cDCs) in response to repeated exposure to lipopolysaccharide (LPS), a ligand of TLR4, by mimicking the mechanism of endotoxin tolerance. Subsequently, the protective effect of cDCs' conditionate with LPS will be describe in in vivo inflammatory model of endotoxemia. Finally, we illustrate the method to study the ability of LPS-conditionate cDCs to promote T regulatory cells in ex vivo system.

Indoleamine 2,3-dioxygenase 1 activation in mature cDC1 promotes tolerogenic education of inflammatory cDC2 via metabolic communication

Conventional dendritic cells (cDCs), cDC1 and cDC2, act both to initiate immunity and maintain self-tolerance. The tryptophan metabolic enzyme indoleamine 2,3-dioxygenase 1 (IDO1) is used by cDCs in maintaining tolerance, but its role in different subsets remains unclear. At homeostasis, only mature CCR7⁺ cDC1 expressed IDO1 that was dependent on IRF8. Lipopolysaccharide treatment induced maturation and IDO1-dependent tolerogenic activity in isolated immature cDC1, but not isolated cDC2. However, both human and mouse cDC2 could induce IDO1 and acquire tolerogenic function when co-cultured with mature cDC1 through the action of cDC1-derived l-kynurenine. Accordingly, cDC1-specific inactivation of IDO1 in vivo exacerbated disease in experimental autoimmune encephalomyelitis. This study identifies a previously unrecognized metabolic communication in which IDO1-expressing cDC1 cells extend their immunoregulatory capacity to the cDC2 subset through their production of tryptophan metabolite l-kynurenine. This metabolic axis represents a potential therapeutic target in treating autoimmune demyelinating diseases.

Liver gene therapy with intein-mediated F8 trans-splicing corrects mouse haemophilia A

Liver gene therapy with adeno‐associated viral (AAV) vectors is under clinical investigation for haemophilia A (HemA), the most common inherited X‐linked bleeding disorder. Major limitations are the large size of the F8 transgene, which makes packaging in a single AAV vector a challenge, as well as the development of circulating anti‐F8 antibodies which neutralise F8 activity. Taking advantage of split‐intein‐mediated protein trans‐splicing, we divided the coding sequence of the large and highly secreted F8‐N6 variant in two separate AAV‐intein vectors whose co‐administration to HemA mice results in the expression of therapeutic levels of F8 over time. This occurred without eliciting circulating anti‐F8 antibodies unlike animals treated with the single oversized AAV‐F8 vector under clinical development. Therefore, liver gene therapy with AAV‐F8‐N6 intein should be considered as a potential therapeutic strategy for HemA.

Amniotic fluid stem cell-derived extracellular vesicles are independent metabolic units capable of modulating inflammasome activation in THP-1 cells

An immunoregulatory role of stem cells, often mediated by their secretome, has been claimed by several studies. Stem cell-derived extracellular vesicles (EVs) are crucial components of the secretome. EVs, a heterogeneous group of membranous vesicles released by many cell types into the extracellular space, are now considered as an additional mechanism for intercellular communication. In this study, we aimed at investigating whether human amniotic stem cell-derived extracellular vesicles (HASC-EVs) were able to interfere with inflammasome activation in the THP-1 cell line. Two subsets of HASC-EVs were collected by sequential centrifugation, namely HASC-P10 and HASC-P100. We demonstrated that HASC-EVs were neither internalized into nor undertake a direct interaction with THP-1 cells. We showed that HASC-P10 and P100 were able to intrinsically produce ATP, which was further converted to adenosine by 5'-nucleotidase (CD73) and ectonucleoside triphosphate diphosphohydrolase-1 (CD39). We found that THP-1 cells conditioned with both types of HASC-EVs failed to activate the NLRP3/caspase-1/inflammasome platform in response to LPS and ATP treatment by a mechanism involving A2a adenosine receptor activation. These results support a role for HASC-EVs as independent metabolic units capable of modifying the cellular functions, leading to anti-inflammatory effects in monocytic cells.

Anakinra restores cellular proteostasis by coupling mitochondrial redox balance to autophagy

Autophagy selectively degrades aggregation-prone misfolded proteins caused by defective cellular proteostasis. However, the complexity of autophagy may prevent the full appreciation of how its modulation could be used as a therapeutic strategy in disease management. Here we define a molecular pathway through which recombinant interleukin-1 receptor antagonist (IL-1Ra, anakinra) affects cellular proteostasis independently from the IL-1 receptor (IL-1R1). Anakinra promoted H2O2-driven autophagy through a xenobiotic sensing pathway involving the aryl hydrocarbon receptor that, activated through the indoleamine 2,3-dioxygenase 1-kynurenine pathway, transcriptionally activates NADPH Oxidase 4 independent of the IL-1R1. By coupling the mitochondrial redox balance to autophagy, anakinra improved the dysregulated proteostasis network in murine and human cystic fibrosis. We anticipate that anakinra may represent a therapeutic option in addition to its IL-1R1 dependent anti-inflammatory properties by acting at the intersection of mitochondrial oxidative stress and autophagy with the capacity to restore conditions in which defective proteostasis leads to human disease.

Hops/Tmub1 Heterozygous Mouse Shows Haploinsufficiency Effect in Influencing p53-Mediated Apoptosis

HOPS is a ubiquitin-like protein implicated in many aspects of cellular function including the regulation of mitotic activity, proliferation, and cellular stress responses. In this study, we focused on the complex relationship between HOPS and the tumor suppressor p53, investigating both transcriptional and non-transcriptional p53 responses. Here, we demonstrated that Hops heterozygous mice and mouse embryonic fibroblasts exhibit an impaired DNA-damage response to etoposide-induced double-strand breaks when compared to wild-type genes. Specifically, alterations in HOPS levels caused significant defects in the induction of apoptosis, including a reduction in p53 protein level and percentage of apoptotic cells. We also analyzed the effect of reduced HOPS levels on the DNA-damage response by examining the transcript profiles of p53-dependent genes, showing a suggestive deregulation of the mRNA levels for a number of p53-dependent genes. Taken together, these results show an interesting haploinsufficiency effect mediated by Hops monoallelic deletion, which appears to be enough to destabilize the p53 protein and its functions. Finally, these data indicate a novel role for Hops as a tumor-suppressor gene in DNA damage repair in mammalian cells.

Tryptophan Metabolites at the Crossroad of Immune-Cell Interaction via the Aryl Hydrocarbon Receptor: Implications for Tumor Immunotherapy

The Aryl hydrocarbon receptor (AhR) is a critical regulator of both innate and adaptive immune responses, with potent immunomodulatory effects that makes this receptor an attractive molecular target for novel therapeutics. Accumulating evidence indicates that diverse—both host’s and microbial—tryptophan metabolites profoundly regulate the immune system in the host via AhR, promoting either tolerance or immunity, largely as a function of the qualitative and quantitative nature of the metabolites being contributed by either source. Additional findings indicate that host and microbiota-derived tryptophan metabolic pathways can influence the outcome of immune responses to tumors. Here, we review recent studies on the role and modalities of AhR activation by various ligands, derived from either host-cell or microbial-cell tryptophan metabolic pathways, in the regulation of immune responses. Moreover, we highlight potential implications of those ligands and pathways in tumor immunotherapy, with particular relevance to checkpoint-blockade immune intervention strategies.

An objective, markerless videosystem for staging facial palsy

Purpose

To propose a new objective, video recording method for the classification of unilateral peripheral facial palsy (UPFP) that relies on mathematical algorithms allowing the software to recognize numerical points on the two sides of the face surface that would be indicative of facial nerve impairment without positioning of markers on the face.

Methods

Patients with UPFP of different House–Brackmann (HB) degrees ranging from II to V were evaluated after video recording during two selected facial movements (forehead frowning and smiling) using a software trained to recognize the face points as numbers. Numerical parameters in millimeters were obtained as indicative values of the shifting of the face points, of the shift differences of the two face sides and the shifting ratio between the healthy (denominator) and the affected side (numerator), i.e., the asymmetry index for the two movements.

Results

For each HB grade, specific asymmetry index ranges were identified with a positive correlation for shift differences and negative correlation for asymmetry indexes.

Conclusions

The use of the present objective system enabled the identification of numerical ranges of asymmetry between the healthy and the affected side that were consistent with the outcome from the subjective methods currently in use.

The cellular prion protein beyond prion diseases

The cellular prion protein (PrPC), a cell surface glycoprotein originally identified for its central role in prion diseases (also called transmissible spongiform encephalopathies), has recently been implicated in the pathogenesis of other neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases, by acting as a toxicity-transducing receptor for different misfolded protein isoforms, or in some case by exerting neuroprotective effects. Interestingly, PrPC has also been reported to play unexpected functions outside the nervous system, for example by contributing to myelin homeostasis, regulating specific processes of the immune system and participating in various aspects of cancer progression. Collectively, these observations point to a much broader role for PrPC in physiological and disease processes than originally assumed. In this manuscript, we provide an overview of what is known about the role of PrPC beyond prion disorders and discuss the potential implications of targeting this protein in different diseases.

Pharmacologic Induction of Endotoxin Tolerance in Dendritic Cells by L-Kynurenine

Endotoxin tolerance aims at opposing hyperinflammatory responses to lipopolysaccharide (LPS) exposure. The aryl hydrocarbon receptor (AhR) participates in protection against LPS-mediated tissue damage, as it plays a necessary role in restraining the proinflammatory action of IL-1β and TNF-α while fostering the expression of protective TGF-β. TGF-β, in turn, promotes durable expression of the immune regulatory enzyme indoleamine 2,3-dioxygenase 1 (IDO1). IDO1 degrades L-tryptophan to L-kynurenine-an activating ligand for AhR-thus establishing a feed-forward loop. In this study, we further demonstrate that L-kynurenine also promotes the dissociation of the Src kinase-AhR cytosolic complex, leading to the activation of both genomic and non-genomic events in conventional dendritic cells (cDCs) primed with LPS. Specifically, the Src kinase, by phosphorylating the downstream target IDO1, triggers IDO1's signaling ability, which results in enhanced production of TGF-β, an event key to establishing full endotoxin tolerance. We demonstrated that exogenous L-kynurenine can substitute for the effects of continued or repeated LPS exposure and that the AhR-Src-IDO1 axis represents a critical step for the transition from endotoxin susceptibility to tolerance. Moreover, much like fully endotoxin-tolerant dendritic cells (DCs) (i.e., treated twice with LPS in vitro), DCs-treated once with LPS in vitro and then with kynurenine-confer resistance on naïve recipients to an otherwise lethal LPS challenge. This may have clinical implications under conditions in which pharmacologically induced onset of endotoxin tolerance is a therapeutically desirable event.

Engagement of Nuclear Coactivator 7 by 3-Hydroxyanthranilic Acid Enhances Activation of Aryl Hydrocarbon Receptor in Immunoregulatory Dendritic Cells

Indoleamine 2,3-dioxygenase 1 (IDO1) catalyzes the first step in the kynurenine pathway of tryptophan (Trp) degradation that produces several biologically active Trp metabolites. L-kynurenine (Kyn), the first byproduct by IDO1, promotes immunoregulatory effects via activation of the Aryl hydrocarbon Receptor (AhR) in dendritic cells (DCs) and T lymphocytes. We here identified the nuclear coactivator 7 (NCOA7) as a molecular target of 3-hydroxyanthranilic acid (3-HAA), a Trp metabolite produced downstream of Kyn along the kynurenine pathway. In cells overexpressing NCOA7 and AhR, the presence of 3-HAA increased the association of the two molecules and enhanced Kyn-driven, AhR-dependent gene transcription. Physiologically, conventional (cDCs) but not plasmacytoid DCs or other immune cells expressed high levels of NCOA7. In cocultures of CD4⁺ T cells with cDCs, the co-addition of Kyn and 3-HAA significantly increased the induction of Foxp3⁺ regulatory T cells and the production of immunosuppressive transforming growth factor β in an NCOA7-dependent fashion. Thus, the co-presence of NCOA7 and the Trp metabolite 3-HAA can selectively enhance the activation of ubiquitary AhR in cDCs and consequent immunoregulatory effects. Because NCOA7 is often overexpressed and/or mutated in tumor microenvironments, our current data may provide evidence for a new immune check-point mechanism based on Trp metabolism and AhR.

Discovery of potent p38α MAPK inhibitors through a funnel like workflow combining in silico screening and in vitro validation

This work describes the rational discovery of novel chemotypes of p38α MAPK inhibitors using a funnel approach consisting of several computer-aided drug discovery methods and biological experiments. Among the identified hits, four compounds belonging to different chemical families showed IC₅₀ values lower than 10 μM. In particular, the 1,4-benzodioxane derivative 5 turned out to be a potent and efficient p38α MAPK inhibitor having IC₅₀ = 0.07 μM, and LE_exp and LipE values of 0.38 and 4.8, respectively; noteworthy, the compound had also a promising kinase selectivity profile and the capability to suppress p38α MAPK effects in human immune cells. Overall, the collected findings highlight that the applied strategy has been successful in generating chemical novelty in the inhibitor kinase field, providing suitable chemical candidates for further inhibitor optimization.

S1P promotes migration, differentiation and immune regulatory activity in amniotic-fluid-derived stem cells

Stem cells have high potential for cell therapy in regenerative medicine. We previously isolated stem cell types from human amniotic fluid, derived from prenatal amniocentesis. One type, characterized by a fast doubling time, was designated as fast human amniotic stem cells (fHASCs). These cells exhibited high differentiation potential and immunoregulatory properties. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid metabolite that influences stem-cell pluripotency, differentiation, mobility, and regulates immune functions. In this study, we investigated the influence of S1P on fHASC migration, proliferation, differentiation and immune regulatory functions. We found that fHASC stimulation with S1P potentiated their migratory and proliferative activity in vitro. Notably, short fHASC exposure to S1P enhanced their differentiation towards multiple lineages, including adipocytes, osteocytes and endothelial cells, an effect that was associated with downregulation of the main transcription factors involved in the maintenance of a stem-cell undifferentiated state. A specific crosstalk between S1P and tumor growth factor β1 (TGF-β1) has recently been demonstrated. We found that fHASC exposure to S1P in combination with TGF-β1 promoted the expression of the immune regulatory pathway of indoleamine 2,3-dioxygenase 1 (IDO1). In addition, human peripheral blood mononuclear cells, co-cultured with fHASCs treated with S1P and TGF-β1, expanded regulatory T-cells, via a mechanism requiring IDO1. Overall, this study demonstrates that S1P potentiates several properties in fHASCs, an effect that may be critical for exploiting the therapeutic potential of fHASCs and might explain the specific effects of S1P on stem cells during pregnancy.

A novel kynurenine-dependent circuit in DC1 promote IDO1 expression in DC2 leading to experimental autoimmune encephalomyelitis suppression

Classical dendritic cells (cDCs) are professional antigen-presenting cells that play a key role in shaping appropriate immune responses. DCs are a potent T cell activators but they are also involved in maintaining immune homeostasis and self-tolerance. DCs can be classified into three major types: pDC, DC1 and DC2. One mechanism by which DCs regulate tolerance involves indoleamine 2,3-dioxygenase 1 (IDO1) a tryptophan (Trp) metabolizing enzyme. In this study, we analyzed the ability of L-Kyn to induce tolerogenic IDO1 pathway in different DCs subsets in vitro and in vivo model of experimental autoimmune encephalomyelitis (EAE). We show that inflammatory stimuli, like LPS, was able to induce IDO1 only in DC1, but not in DC2 or pDC, when DCs were treated as isolated cultures. In contrast, when LPS was added to cultures containing all three DC subsets, LPS could also induce IDO1 expression in DC2, which acquired tolerogenic function. Induction of IDO1 in DC2 involved a novel DC1-DC2 communication pathway mediated by a Kyn-AhR-RelB axis. Kynurenine produced by DC1 activates AhR in DC2 inducing IDO1 in a RelB-dependent manner. In vitro L-Kyn treatment impaired DC2 T cells priming ability causing suppression of MOG-specific reactivity with an increment of Foxp3+ CD4+ T cells. In vivo, oral administration of L-Kyn induces functional Treg cells that suppress EAE and this effect is completely abrogated in Ahrflox/floxCD11C Cre+ mice. These data suggest that in specific microenvironments, small numbers of IDO1-expressing DC1 may spread tolerogenic activity to DC2 cells through a kynurenine-AhR axis and L-Kyn could constituting a unique endogenous molecule for therapeutic immunomodulation of inflammatory and autoimmune diseases.

Statins regulates inflammatory macrophage phenotype through the activation of AhR

Statins are 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase competitive inhibitors, that lower blood cholesterol, but also exert potent anti-inflammatory effects. The xenobiotic receptor, aryl hydrocarbon receptor (AhR), plays crucial role in the control of inflammatory responses. Evidences suggest that selected statins promote the transcription of the main AhR target gene, cytochrome P450 family 1 (Cyp1a1). Macrophages are essential components of innate and adaptive immunity, characterized by AhR expression and activity. Based on these evidences, we investigated potential AhR-mediated immune regulatory properties of statins in Bone Marrow Derived Macrophages (BMDM).

We found that BMDM activation with the pro-inflammatory cytokine TNFa induced the inflammatory marker, inducible nitric oxide synthase (iNOS), which was completely prevented in BMDMs treated with TNFa in combination with specific statins, namely, atorvastatin and rosuvastatin. We confirmed high AhR expression in BMDM that was increased upon treatment with TNFa. We investigated the ability of different statins to activate AhR using a luciferase reporter assay cell lines and in BMDCs. We found that selected statins, such as atorvastatin and rosuvastatin, activated AhR in a dose dependent manner, an activation prevented in cells expressing selected AhR mutants. Notably, AhR deficient BMDMs, expressed undetectable levels of the main statin target protein HMG-CoA, which was instead highly expressed in wild type BMDMs.

These data demonstrate that natural or synthetic statins can play regulatory roles in macrophages. Moreover, our results suggest a potential involvement of AhR in statin-mediated anti-inflammatory effects in macrophages.

Small molecule modulators of prion protein (PrpC) in Dendritic cells regulate inflammatory responses in a model of Multiple Sclerosis

Experimental autoimmune encephalomyelitis (EAE) is the most commonly used experimental model for human multiple sclerosis, an autoimmune disease driven by differentiated Th1 and Th17 cells, and inflammatory dendritic cells (DCs). Recent data show that EAE is worsened in mice lacking PrPC protein and disease exacerbation has been attributed to T cells, which would differentiate into more aggressive effectors, when deprived of PrPC.

Novel compounds, modulating PrPC activity, have been recently developed, although not tested in EAE models yet. Interestingly, by specific gene array studies, we found that PrPC was highly expressed in DCs and differentially expressed among selected DC subsets. Moreover, by using a series of computational, and biochemical assays we identified novel small molecules, able to modulate PrPC function in specific cell lines overexpressing PrPC. By employing such tools, we studied the impact of PrPC modulation in promoting regulatory DC subsets. To this aim, DCs were treated either with novel PrPC modulators or a reference PrPC binding molecule Fe (III)-TMPyP. Then, they were co-cultured with sorted naïve CD4+ T cells in vitro. Notably, we found a significant expansion of FOXP3+CD4+ T regulatory (Treg) cells in cultures containing DC subsets, which were pre-treated with the specific PrPC modulators. Moreover, in a EAE model, we showed that systemic administration of such PrPC regulators, resulted in significant reduction of disease severity, compared to untreated controls. Overall, our results suggest that PrPC modulation in selected DC subsets may represent a novel means to restrain inflammatory T cell effectors, resulting in reduced inflammation, demyelination, and axonal injury in a model of EAE.

The engagement of the aryl hydrocarbon receptor by tryptophan derivatives can prevent the development of anti-FVIII antibodies in an experimental model of hemophilia A

Patients affected by haemophilia A require treatment with factor VIII (FVIII) protein. The most relevant complication is the development of neutralizing FVIII-specific antibodies or “inihibitors”. We reported that the inhibitor-positive status was associated with reduced activity of the immune-regulatory enzyme indoleamine 2,3-dioxygenase 1 (IDO1), that promotes regulatory effects via the production of tryptophan catabolites, known as kynurenines. Some of those tryptophan derivatives are endogenous ligands for the Aryl hydrocarbon receptor (AhR). In this study we tested the potential of tryptophan-related AhR ligands for inhibiting the development of anti-FVIII antibodies in hemophilic (F8 KO) mice. To this aim, F8 KO mice were treated with recombinant human FVIII (rhFVIII) alone or in combination with selected AhR ligands once weekly for four weeks. Antibody titers were tested by specific ELISA and Bethesda test. All mice treated with rhFVIII developed high-titer anti-FVIII antibodies after 4 weeks of treatment. Administration of a specific tryptophan metabolite prevented the generation of anti-FVIII antibodies in almost 80% of F8 KO mice. The protective effect of these AhR ligands was negated by co-administration of the AhR antagonist CH-223191 or in AhR KO mice. Similar results were obtained by administration of engineered gold nanoparticles loaded with the same tryptophan metabolite and rhFVIII. These results suggest that the engagement of AhR, by specific tryptophan derivatives, may be a possible new strategy to control the immune response to rhFVIII. Our findings might lead to the development of novel immunomodulatory interventions for preventing or eradicating inhibitors in hemophilia A patients.

Ocular Symptoms and Signs with Preserved and Preservative-Free Glaucoma Medications

PURPOSE

To compare the prevalence of side effects between eyedrops with or without preservatives, in terms of subjective symptoms and objective signs in patients with open-angle glaucoma.

METHODS

In a multicenter cross-sectional epidemiologic survey in four European countries, ophthalmologists in private practice enrolled 9658 nonconsecutive patients using preservative (P) or preservative-free (PF) beta-blocking eyedrops between June 1997 and December 2003. Subjective symptoms, conjunctival and palpebral signs, and superficial punctate keratitis were explored before and after a change in therapy. For statistical analysis, a Chi-square test was used to calculate the differences in the prevalence of symptoms and signs with or without preservatives.

RESULTS

A total of 74% of the patients used P, 12% PF, 10% a P-PF combination, and in 4% the type of medication was unknown. Each recorded symptom and all the palpebral, conjunctival, and corneal signs were significantly more frequent (p<0.0001) in the P-group than in the PF-group, such as pain or discomfort during instillation (48 vs 19%), foreign body sensation (42 vs 15%), stinging or burning (48 vs 20%), and dry eye sensation (35 vs 16%). A total of 68% of the patients had a sec-ond visit performed, of whom 63% (6083) had been evaluated on treatment difference. A significant decrease (p<0.0001) of all ocular symptoms and signs was observed in patients in whom the preserved eyedrops were diminished in number or altered into preservative free drops.

CONCLUSIONS

Compared to preserved eyedrops, preservative free eyedrops are significantly less associated with ocular symptoms and signs of irritation.

Efficacy of the Fixed Combinations of Bimatoprost or Latanoprost plus Timolol in Patients Uncontrolled with Prostaglandin Monotherapy: A Multicenter, Randomized, Investigator-Masked, Clinical Study

Purpose

To compare the efficacy and tolerability of a once-daily evening dose of bimatoprost/timolol fixed combination (BTFC) with that of a once-daily evening dose of latanoprost/timolol fixed combination (LTFC) in patients not controlled with prostaglandins analogues monotherapy.

Methods

A total of 82 patients on prostaglandin analogues monotherapy were enrolled in this prospective, multicenter, investigator masked, clinical study and were randomized to either BTFC (n=47) or LTFC (n=35) topical therapy once at night for 12 weeks. The primary endpoint of the study was to compare the mean daily intraocular pressure (IOP) reduction from baseline between the two treatment arms. Secondary endpoints included the mean daily IOP at 1 and 3 months compared to baseline and the percentage of patients showing a mean IOP reduction from baseline greater than or equal to 15% or 20%.

Results

Mean IOP at baseline was 22.7±2.0 and 22.1±2.6 mmHg in the BTFC and LTFC groups, respectively (p=0.23). Both treatments were effective in reducing the IOP from baseline. The mean IOP reduction was significantly greater in the BTFC group than in the LTFC group (–21.4% vs −13.7%, p<0.001). A higher percentage of patients in the BTFC group showed a mean IOP reduction from baseline ≥ 15% (72.3% vs 40.0%) and ≥ 20% (61.7% vs 17.1%) compared to patients in the LTFC group.

Conclusions

Both BTFC and LTFC were more effective versus the monotherapy with prostaglandin analogues. BTFC demonstrated higher performance than LTFC in terms of relative IOP reduction.

Demographic and Clinical Factors associated with Brimonidine-Induced Ocular Allergy

Purpose.

Ocular allergy induced by brimonidine tartrate 0.2% is a common adverse event that is associated with poor compliance and therefore treatment failure. The authors investigated the demographic and clinical characteristics associated with development of this allergy.

Methods.

In total, 133 patients with ocular hypertension or open angle glaucoma and treated with brimonidine tartrate 0.2% were retrospectively divided into two groups: allergic and nonallergic to brimonidine tartrate 0.2%. Demographic, local, and systemic ocular variables were compared in the two groups.

Results.

Altogether, 13.5% of patients (18 of 133) developed brimonidine ocular allergy, generally within 2 weeks of beginning treatment (mean time 14.8±17.9 days). Compared with the nonallergic group, the allergic group was significantly more likely to have a history of ocular allergy to eyedrops (p=0.048) and to topical beta blockers (p=0.019). Moreover, the allergic group showed decreased tear film production (p=0.044).

Conclusions.

Patients with a history of eyedrop allergy or with reduced tear film production are more likely to develop brimonidine-associated allergy. Brimonidine may therefore not be suitable for patients with a history of allergy.

CpG type-A induction of an early protective environment in experimental multiple sclerosis

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory, demyelinating disease of the CNS that mimics human multiple sclerosis (MS), and it is thought to be driven by Th1 and Th17 myelin-reactive cells. Although adaptive immununity is clearly pivotal in the pathogenesis of EAE – with an essential role of CD4+ T cells – little is known of early, innate responses in this experimental setting. CpG-rich oligodeoxynucleotides (ODNs), typically found in microbial genomes, are potent activators of TLR9 in plasmacytoid dendritic cells (pDCs). In this study, we compared the effects of two types of CpG, namely, type A and type B, on EAE. We found that treatment with CpG type-A ODN (CpG-A) – known to induce high amounts of IFN-α in pDCs – significantly reduced disease severity in EAE, relative to controls (12.63 ± 1.86 vs. 23.49 ± 1.46, respectively; p = 0.001). Treatment also delayed onset of neurological deficits and reduced spinal cord demyelination, while increasing the percentage of splenic regulatory (Foxp3+CD4+) T cells. CpG-A likewise reduced the levels of IL-17 and IFN-γ in the CNS. Mechanistic insight into those events showed that CpG-A promoted a regulatory phenotype in pDCs. Moreover, adoptive transfer of pDCs isolated from CpG-A–treated mice inhibited CNS inflammation and induced disease remission in acute-phase EAE. Our data thus identify a link between TLR9 activation by specific ligands and the induction of tolerance via innate immunity mechanisms.

RhoA signaling through platelet P2Y₁ receptor controls leukocyte recruitment in allergic mice

BACKGROUND

Clinical studies reveal platelet activation in patients with asthma, allergic rhinitis, and eczema. This is distinct from platelet aggregation, which is critical for the maintenance of hemostasis and in which a role for platelet purinergic receptors is well documented. However, purines are also essential for inflammatory cell trafficking in animal models of allergic lung inflammation, which are known to be platelet dependent, yet the role of purines in the platelet activation accompanying inflammation is unknown.

OBJECTIVES

We investigated whether the involvement of purine activation of platelets during allergic inflammation is distinct from purine involvement in platelet aggregation.

METHODS

BALB/c mice were sensitized to ovalbumin and subsequent airway ovalbumin challenge. Bronchoalveolar lavage fluid was analyzed for inflammatory cells, and blood samples were assessed for platelet activation. The role of platelet purinergic receptors and associated signaling mechanisms (RhoA) were assessed.

RESULTS

P2Y₁, but not P2Y₁₂ or P2X₁, antagonism inhibited pulmonary leukocyte recruitment. The formation of platelet-leukocyte complexes in vivo and platelet/P-selectin-dependent polymorphonuclear cell migration in vitro were exclusively platelet P2Y₁ receptor dependent. Furthermore, platelet P2Y₁ activation resulted in RhoA activity in vivo after allergen challenge, and RhoA signaling in platelets through P2Y₁ stimulation was required for platelet-dependent leukocyte chemotaxis in vitro. Leukocyte recruitment in thrombocytopenic mice remained suppressed after reinfusion of platelets pretreated with a P2Y₁ antagonist or a Rho-associated kinase 1 inhibitor, confirming the crucial role of platelet P2Y₁ receptor and subsequent activation of RhoA.

CONCLUSION

RhoA signaling downstream of platelet P2Y₁, but not P2Y₁₂, represents a clear dichotomy in platelet activation during allergic inflammation versus hemostasis.

Near-Field Chemical Composition of Porewaters in a Near-Surface Low-Level Radioactive Waste Vault

A long-term waste degradation experiment has been performed with actual low-level radioactive wastes (LLRW) at the Chalk River Laboratories (CRL), to support the licensing and modelling efforts for near-surface disposal. The wastes consist of paper, mop heads, paper towels, used clothing, etc. The wastes were compacted into bales and sealed into separate steel containers, which were connected to leachate collection systems for sampling. The leachates collected had a composition typical of landfill leachates. The major inorganic ions were Na, Ca, Cl, and Fe, and the ionic strength was ∼0.05 M. The relative distribution of inorganic ions in the leachates was remarkably similar between bales. Volatile fatty acids (VFA) were the major species of dissolved organic carbon (DOC, total DOC up to 7000 mg/L). A typical composition of leachates is proposed, which can be used in geochemical and source term modelling.

The role of Humphrey Matrix testing in the early diagnosis of retinopathy in type 1 diabetes

AIM

The aim of the study was to investigate the role of Humphrey Matrix threshold testing in the detection of early functional retinal impairment in subjects with type 1 diabetes mellitus (DM1) without any signs of retinal vasculopathy, and to investigate the relationship between both functional and structural retinal parameters and metabolic control.

METHODS

Thirty eyes of 30 subjects with DM1, with no sign of retinal vasculopathy, and 30 eyes of 30 age- and sex-matched healthy subjects were enrolled in this cross-sectional clinical study. Functional testing included Humphrey Matrix perimetry and white-on-white Humphrey visual field perimetry (HFA), while retinal nerve fibre layer (RNFL) thickness was measured by scanning laser polarimetry with variable corneal birefringence compensator (GDx VCC).

RESULTS

Matrix mean deviation (MD) was found to be significantly reduced in subjects with DM1 compared with controls (-1.10 (SD 2.98; 95% CI -2.21 to 0.01) vs 1.37 (SD 2.11; 95% CI 0.58 to 2.16), p = 0.0005). HFA MD and pattern standard deviation (PSD) were significantly worse in subjects with DM1 compared with controls (p = 0.010 and p = 0.013 respectively). Among structural parameters, average peripapillary RNFL thickness was reduced in DM1 subjects (p = 0.006). Matrix MD and HFA MD and PSD, and average peripapillary and superior RNFL, were significantly reduced in subjects with DM1 with HbA(1c) > or = 7% compared with controls.

CONCLUSIONS

Functional and structural retinal testing by Humphrey Matrix and GDx VCC could be useful for the identification of early retinal impairment in people with DM1 with no sign of retinal vasculopathy.

Corneal birefringence changes after laser assisted in situ keratomileusis and their influence on retinal nerve fibre layer thickness measurement by means of scanning laser polarimetry

AIM

To evaluate changes in corneal polarisation properties and their influence on peripapillary retinal nerve fibre layer (RNFL) thickness measurements after laser assisted in situ keratomileusis (LASIK) by means of scanning laser polarimetry (SLP) with variable corneal polarisation compensator (VCC) in normal white subjects.

METHODS

SLP was performed by means of GDx VCC on 32 eyes of 32 normal subjects who underwent LASIK for ametropia correction. Corneal polarisation axis and magnitude and RNFL thickness were measured before and 8 days after LASIK. RNFL thickness data and corneal polarimetric data of one randomly selected eye per subject were analysed by the Wilcoxon signed ranks test. Correlations between corneal ablation depth, corneal polarimetric changes, and RNFL thickness changes were investigated using Spearman's rho test.

RESULTS

The corneal polarisation axis significantly shifted from 15.1 degrees (17.0 degrees ) to 6.9 degrees (12.9 degrees ) (p = 0.00006) after LASIK and this change showed a strong correlation with corneal ablation depth (rho = -0.7, p = 0.00002). Among GDx parameters, TSNIT, SUP, and SD showed significant changes after LASIK and for SUP and SD these changes were well correlated with the shift in corneal polarisation axis (rho = 0.54, p = 0.03 and rho = 0.45, p = 0.01, respectively). SUP and SD changes were neutralised after compensating for corneal polarimetric changes but not TSNIT changes. NFI, a discriminating parameter, was found to be affected after LASIK only after compensating for corneal polarimetric changes.

CONCLUSIONS

LASIK induces a shift in corneal polarisation axis which is responsible for inaccuracies in RNFL thickness measurements. A customised compensation for corneal polarimetric changes after LASIK allows normalisation of some of the thickness parameters except for TSNIT and NFI.

Pulsatile ocular blood flow during pregnancy

PURPOSE

To study pulsatile ocular blood flow (POBF) throughout pregnancy.

METHODS

We enrolled twenty-seven healthy women in the first trimester of gestation, only ten of which were followed through the second trimester, and fourteen non pregnant healthy women. In each subject we measured POBF with the POBF pneumotonometer (OBF Ltd. UK), IOP, blood pressure (BP) and heart rate (HR). An unpaired Student t-test was used to compare pregnant women with non-pregnant women, and a two-tailed paired Student t-test was used to compare the same women in the first and second trimester of pregnancy. p <0.05 is considered statistically significant.

RESULTS

Results are presented as means +/- SD. In the first trimester of pregnancy the age was 32 +/- 6, POBF 1516.4 +/- 382 ml/min, IOP 13 +/- 3 mmHg, BP 92 +/- 6 mmHg, and HR 86 +/- 14 beats/min. In the second trimester POBF was 1629.11 +/- 352.4 ml/min, intraocular pressure (IOP) 12 +/- 3 mmHg, BP 96 +/- 3 mmHg, and HR 93 +/- 10 beats/min. In the control group the age was 27 +/- 9, POBF 972.23 +/- 329.3 ml/min, BP 88 +/- 4.3 mmHg, and HR 80 +/- 14 beats/min. POBF increases during the first trimester (p = 0.00008). In the second trimester POBF was higher compared to the first trimester (p = 0.0008). Non significant differences were observed for the other parameters.

CONCLUSIONS

The POBF increases throughout gestation. During pregnancy there is an increase in estrogen which induces endothelial-dependent vasodilatation in several tissues. The estrogen changes may influence POBF.

Correlation between optical coherence tomography, pattern electroretinogram, and visual evoked potentials in open-angle glaucoma patients

OBJECTIVE

[corrected] To correlate the nerve fiber layer (NFL) thickness and the visual function evaluated by electrophysiologic retinal and cortical responses assessed in open-angle glaucoma (OAG) eyes.

DESIGN

Prospective case-control study.

PARTICIPANTS

Thirty glaucoma patients (mean age, 47.1 +/- 7.15 years; refractive error range, +/- 2 spherical equivalent) with a mean deviation of computerized static perimetry (24/2 Humphrey, Dublin, CA) from -5 to -28 dB and intraocular pressure less than 21 mmHg on pharmacologic treatment and 14 age-matched control participants.

METHODS

Nerve fiber layer thickness was measured by optical coherence tomography. Retinal and visual pathway function was assessed by simultaneously recording pattern electroretinograms (PERGs) and visual evoked potentials (VEPs) using high-contrast (80%) checkerboard stimuli (the single check edges subtend 15 minutes of the visual arc) reversed at the rate of two reversals per second. Linear regression analyses were adopted to establish the correlation between NFL thickness and PERG and VEP parameters.

MAIN OUTCOME MEASURES

Nerve fiber layer thickness measurements in each quadrant (superior, inferior, nasal, and temporal) were taken and then averaged (12 values averaged) and identified as NFL overall, whereas the data obtained in the temporal quadrant only (three values averaged) were identified as NFL temporal. PERG P50 implicit time and P50-N95 amplitude and VEP P100 implicit time and N75-P100 amplitude were also measured.

RESULTS

In OAG eyes, we found a significant (P < 0.01) reduction in NFL thickness in both NFL overall and NFL temporal evaluations with respect to the values observed in control eyes. PERG and VEP parameters showed a significant (P < 0.01) delay in implicit time and a reduction in peak-to-peak amplitude. In OAG eyes, the NFL overall and NFL temporal values were significantly correlated (P < 0.01) with the PERG P50 implicit time and P50-95 peak-to-peak amplitude. No correlations (P > 0.01) between NFL values and VEP parameters were found.

CONCLUSIONS

There is a correlation between PERG changes and NFL thickness, but there is no correlation between VEP changes and NFL thickness in patients affected by OAG.

Do sex and hormonal status influence choroidal circulation?

AIMS

To investigate the relation between pulse amplitude (PA), pulsatile ocular blood flow (POBF), and sex and hormonal status.

METHODS

Measurements of POBF and PA were obtained by ocular blood flow tonography in 76 healthy subjects: 32 males and 44 females (age range 17-77 years). Females were divided into two age groups: group 1 (premenopausal) 17-42 years, and group 2 (post-menopausal) 55 years old and over. Two groups of age matched males served as controls.

RESULTS

Premenopausal females demonstrated a significantly higher rate of POBF and PA than age matched males and post-menopausal females.

CONCLUSION

Sex and hormonal status were shown to influence choroidal circulation.

Comparative acute effects of brimonidine 0.2% versus dorzolamide 2% combined with beta-blockers in glaucoma

PURPOSE

To assess the acute intraocular hypotensive efficacy of brimonidine tartrate 0.2% (a highly selective alpha2-adrenergic agonist) compared with dorzolamide 2% (a topical carbonic anhydrase inhibitor) as adjunct therapy to topical beta-blockers in patients with primary open-angle glaucoma.

METHODS

A randomized cross-over masked study was performed. We enrolled one eye of each of 28 patients who were on different beta-blocker therapy. We measured the intraocular pressure (IOP) 2 h after the beta-blocker instillation; we then randomly administered one of the two drugs and we compiled an IOP diurnal curve. One month later we repeated the same procedures with the second drug. Unpaired Mann-Whitney U-test was used to compare decreases in IOP between the two drugs (P<0.05).

RESULTS

Both brimonidine 0.2% and dorzolamide 2% have good ocular hypotensive efficacy, significantly lowering IOP when compared to beta-blocker therapy alone, for the whole diurnal curve. Maximum mean percent IOP decrease from baseline was 22.0+/-15.7% (4.0+/-2.9 mmHg) for dorzolamide 2% 6 h after instillation and 35.5+/-16.4% (7.0+/-4.1 mmHg) for brimonidine 0.2% 8 h after administration of the drug. When we compared the two treatments, brimonidine 0.2% showed a higher hypotensive effect than 2% dorzolamide after 4 h (28.4+/-16.8% vs 17.6 +/-9.3%; P=0.04) and 8 h (35.5+/-16.4% vs 21.6 +/-10.8%; P=0.04).

CONCLUSION

This study indicates that 0.2% brimonidine acutely associated with beta-blockers is an interesting new combination treatment useful in the management of glaucoma.

Correlation between morphological and functional retinal impairment in multiple sclerosis patients

PURPOSE

To assess whether a correlation exists between optic nerve fiber layer (NFL) thickness and the retinal or visual pathway function in multiple sclerosis (MS) patients previously affected by optic neuritis.

METHODS

Fourteen patients with a diagnosis of definite MS were examined. All had been affected by optic neuritis (MSON) with complete recovery of visual acuity (14 eyes included in study). These were compared with 14 eyes from 14 age-matched control subjects. NFL thickness was measured by optical coherence tomography (OCT). Three different measurements in each quadrant (superior, inferior, nasal, and temporal) were taken and averaged. The data in all quadrants (12 values averaged) were identified as NFL Overall, whereas the data obtained in the temporal quadrant only (3 values averaged) were identified as NFL Temporal. Retinal and visual pathway function was assessed by simultaneously recording pattern electroretinograms (PERGs) and visual evoked potentials (VEPs) using high-contrast (80%) checkerboard stimuli subtending 15 minutes and 60 minutes of the visual arc (min arc) and reversed at the rate of two reversals per second.

RESULTS

In MSON eyes there was a significant (P < 0.01) reduction in NFL thickness in both NFL Overall and NFL Temporal evaluations compared with the values observed in control eyes. PERG, (15-min arc checks) and VEP (15-min arc and 60-min arc checks), showed a significant (P < 0.01) delay in latency and reduction in amplitude. NFL Overall and NFL Temporal values were significantly correlated (P < 0.01) to the PERG P50 latency and P50 to N95 amplitude recorded with 15-min arc checks. No correlations (P > 0.01) between NFL values and the other electrophysiological data (PERG recorded with 60-min arc checks and VEP recorded with 15-min arc and 60-min arc checks) were found.

CONCLUSIONS

There is a correlation between PERG changes and NFL thickness in MS patients previously affected by optic neuritis, but there is no correlation between VEP changes and NFL thickness.

Effects of nicergoline on the retinal and cortical electrophysiological responses in glaucoma patients: a preliminary open study

PURPOSE

The retinal dysfunction and the delayed visual cortex responses shown by patients affected by glaucoma can be objectively assessed by Pattern Electroretinogram (PERG) and Visual Evoked Potentials (VEP) recordings. The present study aims to evaluate the effects of nicergoline on the retinal function and on the visual cortical responses in glaucoma patients.

METHODS

Sixty patients (mean age 44.6+/-3.7) with open angle glaucoma were enrolled. The patients were divided into two groups: NG Group, where 30 patients were treated with nicergoline (Cebran((R)), 2 cps day) for 30 days; and CG Group, where 30 patients were not treated. Simultaneous recordings of PERG and VEP were performed in NG patients at the baseline, at 30 days after treatment with nicergoline (day 30), and at 45 days from the end of the treatment (day 75). PERG and VEP were recorded in CG patients at the baseline and after 30 and 75 days. The visual stimulus for recording PERGs and VEPs was a checkerboard whose elements subtended a visual arc of 60' and 15' with a 70% contrast, and alternated at a frequency of 2 Hz.

RESULTS

At the baseline none of the electrophysiological parameters observed in NG Group patients differed (P>0.05) from those of CG Group patients. At days 30 and 75, in CG Group patients the values of the PERG and VEP parameters were unmodified (P>0.05) with respect to the baseline. In NG Group patients, the 30-day treatment period with nicergoline induced a significant (P<0.01) improvement of the PERG and VEP parameters. At day 75 all the electrophysiological parameters of NG Group did not differ significantly (P>0.05) from those at the baseline.

CONCLUSION

Treatment with nicergoline induces an improvement of the retinal function and of the visual cortical responses in patients affected by glaucoma. This effect disappears within 45 days after the suspension of the treatment.

Visual function correlates with nerve fiber layer thickness in eyes affected by ocular hypertension

PURPOSE

To test whether the high variability observed when measuring pattern electroretinogram (PERG), visual evoked potentials (VEP), and spatial contrast sensitivity (SCS) in eyes with ocular hypertension is associated with variation in nerve fiber layer thickness, as measured by optical coherence tomography (OCT).

METHODS

The study involved 32 untreated eyes (32 patients; age range, 29-64 years) showing a normal whiteon-white 24/2 Humphrey (San Leandro, CA) perimetry, IOP between 23 and 28 mm Hg, best corrected acuity of 20/20 or better, and none of the following papillary signs on conventional color stereo slides: rim notch(es), peripapillary splinter hemorrhages, or increased vertical-to-horizontal cup-to-disc ratio. On recruitment, each eye underwent SCS testing, OCT, PERG, and VEP recordings. Linear regression (Pearson's test) or Spearman's rank regression was adopted for the analysis of the data.

RESULTS

The 95% confidence limits of the electrophysiological data were: PERG P50 latency, 59.3 to 63 msec; PERG P50 to N95 amplitude, 0.74 to 1.15 cmV; VEP P100 latency, 113 to 118 msec; VEP N75 to P100 amplitude, 3.81 to 4.90 micromV. The 360 degrees nerve fiber layer thickness overall (NFLO) ranged between 113 and 169 microm (145+/-16 microm; mean+/-SD) and significantly correlated with PERG P50 to N95 amplitude (r: 0.518; P = 0.002), PERG P50 latency (r: -0.470; P = 0.007), VEP N75 to P100 amplitude (r: 0.460; P = 0.008), VEP P100 latency (r = -0.422; P = 0.016) and SCS at 3 cyc/deg (r: -0.358; P = 0.044).

CONCLUSIONS

The variability of PERG, VEP, and SCS testing observed in eyes with ocular hypertension is associated with differences in NFL thickness (the thinner the layer, the worse the visual function).

Cytidine-5'-diphosphocholine (citicoline) improves retinal and cortical responses in patients with glaucoma

PURPOSE

To evaluate the effects of cytidine-5'-diphosphocholine (citicoline) on retinal function and on cortical responses in patients with glaucoma.

DESIGN

Randomized clinical trial.

PARTICIPANTS

Forty patients with open-angle glaucoma were randomly divided into two age-matched groups: citicoline group ([GC] n = 25) and placebo group ([GP] n = 15).

METHODS

The GC patients were treated with Neuroton (citicoline, 1000 mg/day intramuscularly) for 60 days; GP patients were treated with placebo (physiologic solution with additives) for 60 days. After 120 days of washout (day 180), the GC patients were divided into two age-matched groups: in 10 patients (GC1 group) the washout was prolonged for a further 120 days; in 15 patients (GC2 group) a second 60-day period of citicoline treatment was followed by a second 120-day period of washout. At day 180, the washout was extended for another 180 days in GP patients. In all subjects, retinal and cortical responses were evaluated by simultaneous recordings of visual evoked potentials (VEPs) and pattern-electroretinograms (PERGs) at baseline, after 60 days, and after 180 days. At day 300, VEPs and PERGs were also evaluated in GC1 patients, and at 240 and 360 days in GC2 and GP patients.

MAIN OUTCOME MEASURES

Visual evoked potential parameters (P100 latency and N75-P100 amplitude); PERG parameters (P50 latency and P50-N95 amplitude); and intraocular pressure.

RESULTS

The GP patients displayed similar VEP and PERG parameters in all examinations performed. In GC patients, the treatment with citicoline induced a significant (P < 0.01) improvement of VEP and PERG parameters, and their values were significantly different (P < 0.01) with respect to those of GP patients (P < 0.01). Visual evoked potentials and PERGs, recorded in GC patients after washout, revealed that although there was a worsening trend, the electrophysiologic improvement was still maintained. After a second period of washout, GC1 patients had VEP and PERG parameters similar (P > 0.05) to baseline ones and to those of GP patients. In GC2 patients, a second period of citicoline treatment induced a further (P < 0.01) improvement of VEP and PERG parameters

CONCLUSION

Citicoline may induce an improvement of the retinal and of the visual pathway function in patients with glaucoma.

Neural conduction in visual pathways in newly-diagnosed IDDM patients

OBJECTIVES

Visual evoked potentials (VEPs) show abnormal responses in newly-diagnosed insulin-dependent diabetic (IDDM) patients. Electrophysiological methods allow one to dissect and explore different structures contributing to neural conduction in the visual pathways. The aim of our work was to assess whether the VEP abnormalities are due to impaired function of the retinal layers and/or a delayed conduction in the postretinal visual pathways.

METHODS

Simultaneous recordings of VEP and pattern-electroretinogram (PERG) were performed at two intervals (at entry of the study and after 3 months) in 14 newly-diagnosed IDDM patients (age: 24.8+/-6.8 years; duration of disease: 3+/-1.5 months), and in 14 age-matched control subjects.

RESULTS

In comparison with control subjects, IDDM patients showed: VEP P100 latencies significantly delayed (P < 0.01), a significant impairment of all PERG parameters (P < 0.01) and retinocortical time (RCT, difference between VEP P100 and PERG P50 latencies) and latency window (LW, difference between VEP N75 and PERG P50 latencies) also significantly increased (P < 0.01). All electrophysiological parameters were not significantly changed when retested after 3 months. No correlations were found between VEP P100 latency, RCT, LW and PERG parameters.

CONCLUSIONS

Impaired PERG indicates an involvement of the innermost retinal layers; increased values of RCT and LW represent an index of delayed neural conduction in the postretinal visual pathways. Therefore two sources, one retinal (impaired PERG) and one postretinal (delayed RCT and LW), may independently contribute in to the abnormal responses of VEP observed in newly-diagnosed IDDM patients. Three months of relatively-stable metabolic control have not normalized the VEP and PERG impairment.

Electrophysiological assessment of visual function in IDDM patients

Various electrophysiological tests have been employed to reveal functional abnormalities at different levels of the visual system in insulin-dependent diabetic (IDDM) patients. The aim of our work was to assess, with a comprehensive neurophysiological protocol evaluating the retinal, macular and visual pathways functions, whether and when such electrophysiological abnormalities do appear in IDDM patients free of any fluorangiographic sign of retinopathy with various disease duration. Flash-electroretinogram (ERG), oscillatory potentials (OPs), pattern-electroretinogram (PERG), and visual evoked potentials (VEPs) in basal condition and after photostress were assessed in 12 control subjects (C) and 42 aged-matched IDDM patients without clinical retinopathy (DR-) divided, on the basis of the disease duration, into 4 groups (1-5, 6-10, 11-15, 16-20 years). In addition another age-matched group of IDDM patients with a background retinopathy (DR+; n = 12; duration of disease 18 +/- 49 years) was evaluated. In all IDDM DR-patients PERG and VEP were significantly impaired. In addition, groups 11-15 and 16-20 years displayed impaired OPs. All electrophysiological parameters were further impaired in DR+ patients. In conclusion, retinal, macular and visual pathways functions are differently impaired in IDDM (DR-) patients with different disease duration. Electrophysiological impairment starts in the nervous conduction of the visual pathways with an early involvement, goes on in the innermost retinal layers and in the macula and ends in the middle and outer retinal layers.

Histopathological evaluation of retinal damage during intraocular hypertension in rabbit: involvement of ganglion cells and nerve fiber layer

BACKGROUND

Current clinical tests do not detect glaucomatous signs until the onset of substantial retinal damage. Therefore animal models are required to investigate the very early histopathological alterations in glaucoma disease. We used an experimental model of intraocular hypertension to compare early changes in retinal ganglion cell (RGC) density with the thickness of the nerve fiber layer (NFL).

METHODS

Methylcellulose 2% was injected into the anterior chamber of 18 eyes of 18 New Zealand albino rabbits. Intraocular pressure was measured 6 h after the injection and thenceforth once a day using a Shiötz tonometer. Histopathological analysis was performed on days 4, 10, and 15 following the induction of hypertension (six eyes for each group). Sections from the upper temporal retina were stained with hematoxylin-eosin and immunohistochemically using a polyclonal antibody PGP 9.5 to identify RGC. An image analysis system was used to evaluate the RGC and the thickness of the NFL.

RESULTS

We observed a significant increase in intraocular pressure until the end of the experiment. Histological analysis showed, after 10 days of ocular hypertension, a significant decrease in RGC density (P < 0.05) and a significant increase (P < 0.05) in glial cell density. We found a significant correlation between RGC loss and cell area at 4 days (P < 0.01; Cc = 0.86) and at 10 days (P < 0.002; Cc = 0.91) of intraocular hypertension. We did not observe a significant decrease in the NFL thickness until 10 days of intraocular hypertension.

CONCLUSIONS

Our study confirms the size-dependent RGC loss during intraocular hypertension and shows no early decrease in NFL thickness.

Analgesic effect of topical diclofenac versus betamethasone after posterior segment surgery

BACKGROUND

In clinical use, topical diclofenac, a nonsteroidal antiinflammatory, was found to be remarkably effective as an analgesic. A trial was therefore conducted to quantify and compare this effect with that of other drugs commonly used after posterior segment surgery.

METHODS

A single-blind, randomized study of 37 patients undergoing posterior segment surgery was conducted. On the day of surgery and for 30 days thereafter, one group received topical diclofenac 0.1% and one group received topical betamethasone 0.1%. Pain intensity was assessed by two standard psychologic tests, the McGill Pain Questionnaire (MPQ) and Scott's Visual Analogic Scale (VAS).

RESULTS

The group receiving diclofenac had significantly lower pain scores on the MPQ at days 1 and 15 (P < 0.05 and P < 0.03, respectively). The VAS scores were also statistically lower for this group on day 15 (P < 0.03).

CONCLUSION

Topical diclofenac 0.1% has greater analgesic action than topical betamethasone 0.1% without the side effects of steroids, and may be useful after posterior segment surgery.

The effect of increased intraocular pressure on pulsatile ocular blood flow in low tension glaucoma

In the present study the relationship between intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) in low tension glaucoma (LTG) has been investigated. The POBF was measured using the Ocular Blood Flow system of Langham in undisturbed eyes and repeated at IOP increments of about 5 and 10 mmHg in 20 patients affected with bilateral LTG and in 25 healthy subjects matched for age, IOP, refractive error, arterial blood pressure and heart rate. The POBFs were 740.1 (SD 58.83) and 667 (SD 108) microliters/minute (microliter/min) in the control and LTG groups, respectively and statistically significantly different. The POBFs at an IOP increased by 5 mmHg were 658.1 (SD 60.2) and 457.3 (SD 74.8) microliter/min in the control and LTG groups, respectively; in the control group the mean POBF at an IOP increment of 10 mmHg was 552.1 microliters/min (SD 66.9), and in the LTG group was 317.7 microliters/min (SD 85.2). Statistical analysis of the data showed a significant difference of POBFs in the two groups either at an IOP increment of 5 or 10 mmHg (p < 0.0001). The substantial decrease of POBF with increased IOP in LTG eyes compared with normals shows an altered response of the vascular system in LTG. These findings are probably consistent with a lack of the myogenic autoregulation in reply to IOP-induced modifications of the perfusion pressure.