Determinants of impairment in lung diffusing capacity in patients with systemic sclerosis.

OBJECTIVES: Lung diffusing capacity for carbon monoxide (DLCO) is impaired in interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) associated to systemic sclerosis (SSc), but the mechanism of DLCO reduction remains controversial. We hypothesised that the determinants of DLCO impairment differ in interstitial or vascular involvement of the lung of SSc patients. METHODS: DLCO was partitioned into alveolar-capillary membrane conductance (Dm) and pulmonary capillary blood volume (Vc) using combined single-breath DLNO and DLCO measurements. Seventeen SSc patients without pulmonary involvement (SSc), 20 SSc patients with ILD (SSc-ILD), with and without PAH, and 21 healthy controls were included. RESULTS: DLNO and Dm were reduced in SSc patients as compared with controls, whereas Vc was not significantly different. SSc-ILD patients showed a highly significant decrease in Dm and Vc as compared with SSc patients and controls. Vc tended to be more reduced than Dm in SSc-ILD patients with PAH. Dm and Vc were negatively correlated with PAPs and HCRT scores, but the relationship with the HRCT score was stronger. CONCLUSIONS: DLNO is more sensitive than DLCO in detecting functional impairment in SSc without radiologic or haemodynamic alterations. A disproportional reduction of Dm relative to Vc suggests a thickening of the blood-gas diffusion barrier in these patients. In SSc patients with detectable ILD, the gas exchange impairment is due to both components of lung diffusing capacity, and partitioning of DLCO in Dm and Vc is of little use in distinguishing the patients with only ILD from those with ILD complicated by PAH.

Blood-aqueous barrier integrity in patients with Graves' ophthalmopathy (GO), before and after rehabilitative surgery.

PURPOSE: The study was conducted to analyze aqueous flare and its correlations in patients with Graves' ophthalmopathy (GO) undergoing orbital decompression, extraocular muscle, and eyelid surgery. Prospective interventional case series. PATIENTS AND METHODS: Forty-eight eyes of 27 patients (20 female and 7 male, aged 54.4 ± 5.7) undergoing surgical treatment for GO. Eighteen eyes of nine patients (aged 55.3 ± 3.6) undergoing orbital decompression. Nineteen eyes of 11 patients (aged 54.7 ± 5.6) undergoing extraocular muscle surgery and 13 eyes of 7 patients (aged 53.9 ± 4.9) undergoing eyelid surgery and control group (34 patients aged 53.9 ± 5.1). Laser flare analysis and clinical assessment were performed before surgery and at 1 day, 7 days, and 3 months following surgery. RESULTS: Aqueous flare was significantly higher in patients with GO (14.03 ± 8.45) before intervention than in the control group (7.89 ± 3.56) (P<0.001), and correlated with Clinical Activity Score and intraocular pressure. In the patients undergoing orbital decompression, flare increased from 17.77 ± 10.63 pc/ms to 38.32 ± 13.56 pc/ms on the first day and 41.31 ± 17.19 pc/ms on the seventh day and returned to 16.01 ± 8.58 pc/ms in 3 months. In patients undergoing extraocular muscle surgery flare increased from 13.05 ± 6.50 to 23.04 ± 11.53 pc/ms (P<0.001) on the first day and returned to 18.02 ± 14.09 pc/ms on the seventh day. Eyelid surgery did not change flare values. CONCLUSIONS: Orbital decompression disrupts blood-aqueous barrier (BAB). The integrity of BAB returns to preoperative status within 3 months. Extraocular muscle surgery mildly affects BAB integrity, and the effect subsides within 7 days. Eyelid surgery does not affect BAB.

Effects of repeated Cr(VI) intratracheal instillation on club (Clara) cells and activation of nuclear factor-kappa B pathway via oxidative stress.

Hexavalent chromium [Cr(VI)] exposure is known to induce respiratory inflammation and contribute to lung cancer development, but little is known about its target cell type in lung. In the current study, we investigated the effects of repeated Cr(VI) intratracheal instillation on club (Clara) cells and club (Clara) cell secretory protein (CC16) in rats and explored whether the nuclear factor-kappa B (NF-κB) related pathway was involved. We also studied the role of orally delivered Zn against Cr-induced adverse health effects. For four weeks, sixty Sprague-Dawley male rats received weekly intratracheal instillation of potassium dichromate (K2Cr2O7) at 0, 0.063 and 0.630mgCr/kg with or without daily intragastric administration of zinc sulfate (ZnSO4) at 10mg Zn/kg. Results showed that exposure to Cr(VI) significantly increased the organ coefficient of lung (organ weight as a percentage of body weight), albumin and total protein level in bronchoalveolar lavage fluid (BALF), indicating lung injury and compromised bronchoalveolar/blood barrier (BA/BB) integrity. With increasing Cr(VI) dose, the secretion of CC16 decreased in a dose-dependent manner, suggesting that CC16 can serve as a peripheral biomarker for club cell damage during early lung injury induced by Cr(VI). Increased expression of NF-κB were observed in club cells in both Cr-exposed groups, indicating upregulation of NF-κB, which can be induced by reactive oxygen species (ROS) generated by club cells during Cr reduction with repetitive Cr(VI) exposure. Cr-induced DNA damage was also observed, as significant increase of 8-OHdG was found with Cr exposure at 0.630mg/kg week. Oral Zn supplementation did not alleviate changes in serum CC16 level under Cr(VI) exposure, indicating its failure in protecting against Cr(VI)-induced club cell damage.

Effects of benzalkonium chloride on the blood-aqueous and blood-retinal barriers of pseudophakic eyes.

PURPOSE: To evaluate the effects of benzalkonium chloride (BAK) on the blood-aqueous (BAB) and blood-retinal barriers (BRB) of pseudophakic eyes. METHODS: Prospective, randomized, investigator-masked, comparative study. Patients were randomly assigned to preservative-free artificial tears or BAK-preserved artificial tears. One drop of artificial tears was instilled 4 times a day in the study eye, starting the day after randomization for 30 days. Anterior chamber flare was assessed by a laser flare meter (LFM) and macular thickness measurements were obtained with optical coherence tomography, before, 15, and 30 days after randomization. RESULTS: A total of 44 healthy eyes of 44 pseudophakic volunteers were recruited. There were no significant differences regarding demographics (age, gender, and race distributions) and clinical characteristics (eye, mean intraocular pressure, and mean best-corrected visual acuity) between the 2 groups (P>0.05). No significant differences in baseline mean LFM values were observed (P=0.262). However, we detected a statistically significant increase in mean LFM measurements in the BAK-preserved group (11.4 ± 5.1 ph/ms) (P=0.017) after 15 days. After 30 days, the BAK-preserved group maintained significantly higher flare values (11.9 ± 5.9 ph/ms) compared with baseline (P=0.043). On the other hand, the preservative-free group showed mean flare values of 8.4 ± 2.5 ph/ms, not significantly different from those obtained at baseline (P=1.00). We observed no statistically significant change in macular thickness measurements at days 15 and 30 in either group (P>0.05). Cystoid macular edema was not detected in this series. CONCLUSIONS: Our results suggest that a short-term exposure to BAK can cause disruption of the BAB, without altering the BRB in pseudophakic eyes.

Disruption of the blood-aqueous barrier and lens abnormalities in mice lacking lysyl oxidase-like 1 (LOXL1).

PURPOSE: Exfoliation syndrome (ES) is commonly associated with glaucoma, premature cataracts, and other ocular and systemic pathologies. LOXL1 gene variants are significantly associated with ES; however, the role of the protein in ES development remains unclear. The purpose of this study was to characterize the ocular phenotype in Loxl1(-/-) (null) mice. METHODS: Loxl1 null mice and strain-matched controls (C57BL) were evaluated by clinical and histologic analyses. RESULTS: Anterior segment histology showed a pronounced vesiculation of the anterior lens in the null mice. The lesions were subcapsular and in direct apposition with the posterior iris surface. Fluorescein angiography showed increased diffusion of fluorescein into the anterior chamber of the null mice compared with age-matched controls (P = 0.003, two-tailed, unequal variance t-test), suggesting compromise of the blood-aqueous barrier. Intraocular pressure measurements were within the normal range (16.5 ± 2.0 mm Hg) in null mice up to 1 year of age. Immunohistochemistry showed decreased elastin in the iris and ciliary body in the null mouse compared with controls. CONCLUSIONS: Elimination of LOXL1 in mice impairs the blood-aqueous humor barrier in the ocular anterior segment and causes lens abnormalities consistent with cataract formation, but does not result in deposition of macromolecular material or glaucoma. These results show that mice lacking LOXL1 have some ES features but that complete disease manifestation requires other factors that could be genetic and/or environmental.

Disorder of blood-aqueous barrier following Ahmed Glaucoma Valve implantation.

BACKGROUND: Ahmed Glaucoma Valve implantation (AGVI) is used to treat refractory glaucoma. Breakdown of the blood-aqueous barrier (BAB) has been noted after some surgical techniques. The current study was designed to assess BAB disruption after AGVI. METHODS: Anterior chamber protein content was measured by the laser flare cell photometry in 22 eyes of 22 patients with refractory glaucoma before AGVI and at each postoperative visit up to 1 month. RESULTS: Before AGVI the mean aqueous flare values in all eyes were (15.17 ± 9.84) photon counts/ms. After AGVI, the values significantly increased at day 1, day 3, and week 1 compared to those before AGVI (all P < 0.05) with a peak at day 3. They returned to pre-operative levels at week 2, and were lower than preoperative level at month 1. Eyes with previous intraocular surgery history had greater aqueous flare values than those without previous intraocular surgery history, but there were no significant differences at all time points postoperatively (all P > 0.05). Furthermore, eyes with shallow anterior chambers had greater aqueous flare values at day 3 and week 1 (all P < 0.05). When comparing eyes with other refractory glaucoma conditions, neovascular glaucoma combined with intravitreal bevacizumab injection resulted in lower aqueous flare values after AGVI, but no significant differences were observed at all time points, postoperatively (all P > 0.05). CONCLUSIONS: The BAB was impaired and inflammation was present in the anterior chamber in refractory glaucomatous eyes following AGVI. However, such conditions were resolved within 1 month postoperatively. Intravitreal bevacizumab treatment in neovascular glaucoma eyes before AGVI may prevent BAB breakdown.

The effects of anthrax lethal toxin on host barrier function.

The pathological actions of anthrax toxin require the activities of its edema factor (EF) and lethal factor (LF) enzyme components, which gain intracellular access via its receptor-binding component, protective antigen (PA). LF is a metalloproteinase with specificity for selected mitogen-activated protein kinase kinases (MKKs), but its activity is not directly lethal to many types of primary and transformed cells in vitro. Nevertheless, in vivo treatment of several animal species with the combination of LF and PA (termed lethal toxin or LT) leads to morbidity and mortality, suggesting that LT-dependent toxicity is mediated by cellular interactions between host cells. Decades of research have revealed that a central hallmark of this toxicity is the disruption of key cellular barriers required to maintain homeostasis. This review will focus on the current understanding of the effects of LT on barrier function, highlighting recent progress in establishing the molecular mechanisms underlying these effects.

Alterations in the aqueous humor proteome in patients with a glaucoma shunt device.

PURPOSE: To investigate whether implantation of a glaucoma shunt device leads to inappropriate accumulation of plasma derived proteins in the aqueous humor. METHODS: Aqueous humor samples were collected from 11 patients (study group) with a glaucoma shunt device undergoing either cataract surgery or a corneal transplant and 11 patients (control) with senile cataract undergoing routine cataract extraction. Of the study group, 9 had an Ahmed valve implant and 2 eyes had a Baerveldt implant. Tryptic digests of the mixture of proteins in aqueous humor (AH) were analyzed using Liquid Chromatography/Mass Spectrometry (LC-MS/MS). Proteins were identified with high confidence using stringent criteria and compared quantitatively using a label-free platform (IdentiQuantXL™). RESULTS: We identified 135 proteins in the albumin-depleted fraction in both the study and control group AH. Using stringent criteria, 13 proteins were detected at a significantly higher level compared to controls. These proteins are known to play a role in oxidative stress, apoptosis, inflammation and/or immunity and include gelsolin (p=0.00005), plasminogen (p=0.00009), angiotensinogen (p=0.0001), apolipoprotein A-II (p=0.0002), beta-2-microglobulin (p=0.0002), dickkopf-3 (DKK-3; p=0.0002), pigment epithelium-derived factor (p=0.0002), RIG-like 7-1 (p=0.0002), afamin (p=0.0003), fibronectin 1 (FN1; p=0.0003), apolipoprotein A-I (p=0.0004), activated complement C4 protein (C4a; p=0.0004) and prothrombin (p=0.0004). Many of the identified proteins were novel proteins that have not been associated with glaucoma in prior studies. All but C4a (complement C4 is a plasma protein but not in an activated form) are known plasma proteins and the elevated levels of these proteins in the aqueous humor suggests a breach in the blood-aqueous barrier with passive influx into the anterior chamber of the eye. CONCLUSIONS: The presence of these proteins in the aqueous humor suggests that glaucoma shunt device causes either a breach in blood-aqueous barrier or chronic trauma, increasing influx of oxidative, apoptotic and inflammatory proteins that could potentially cause corneal endothelial damage.

Damage to the blood-aqueous barrier in eyes with primary angle closure glaucoma.

PURPOSE: This study investigates the inflammation in the anterior chamber in eyes with primary angle closure glaucoma (PACG) and evaluates the effect of intraocular pressure (IOP) elevation on the blood-aqueous barrier (BAB). METHODS: Thirty-five patients (35 eyes) with acute primary angle closure glaucoma (APACG), 42 patients (42 eyes) with chronic primary angle closure glaucoma (CPACG), and 50 age-matched healthy controls (50 eyes) were included in this study. The flare value and cell counts were quantified using laser flare cell photometry. Statistical analysis was performed to compare differences in flare value and cell counts between different groups and explore the relation between the inflammation and IOP. RESULTS: The mean flare value (photon counts per millisecond, ph/ms) in the APACG, CPACG, and healthy control group was 141.4±123.1, 7.7±4.1, and 4.5±1.1, respectively. The mean cell counts (cells/0.5 mm(3)) in the three groups were 126.0±67.8, 5.2±5.8, and 0.8±0.7, respectively. The flare value and cell counts in both the APACG group and the CPACG group were significantly higher than those in the healthy control group (p<0.001). Furthermore, the flare value and cell counts in the APACG group were significantly higher than those in the CPACG group (p<0.001). There were positive correlations between the IOP level and flare value (r=0.527, p<0.001), and cell counts(r=0.775, p<0.001), respectively, in the APACG group. CONCLUSIONS: Disrupted BAB and inflammation in the anterior chamber were found in eyes with both kinds of PACG. The damage of BAB was more severe in eyes with APACG than those with CPACG. The IOP elevation, especially a dramatic IOP elevation, might be the factor responsible for the change of BAB in eyes with PACG.

An essential role for RPE-derived soluble VEGF in the maintenance of the choriocapillaris.

Clinical and experimental observations indicate a role for VEGF secreted by the retinal pigment epithelium (RPE) in the maintenance of the choriocapillaris (CC). VEGF in mice is produced as three isoforms, VEGF120, VEGF164, and VEGF188, that differ in their ability to bind heparan sulfate proteoglycan. RPE normally produces the more soluble isoforms, VEGF120 and VEGF164, but virtually no VEGF188, reflecting the fact that molecules secreted by the RPE must diffuse across Bruch's membrane (BrM) to reach the choriocapillaris. To determine the role of RPE-derived soluble VEGF on the choriocapillaris survival, we used mice that produce only VEGF188. VEGF188/188 mice exhibited normal choriocapillaris development. However, beginning at 7 months of age, we observed a progressive degeneration characterized by choriocapillaris atrophy, RPE and BrM abnormalities, culminating in areas of RPE loss and dramatic choroidal remodeling. Increased photoreceptor apoptosis in aged VEGF188/188 mice led to a decline in visual acuity as detected by electroretinogram (ERG). These changes are reminiscent of geographic atrophy (GA) and point to a role for RPE-derived VEGF in the maintenance of the choriocapillaris.

Aqueous flare and cells in Fuchs syndrome.

PURPOSE: To quantitatively evaluate aqueous flare and cells in patients with Fuchs syndrome. METHODS: The medical records of 40 patients (47 eyes) diagnosed with Fuchs syndrome between February 2006 and January 2007 at the Uveitis Study Center of Sun Yat-sen University were retrospectively reviewed. Aqueous flare and cells were clinically evaluated and quantified with laser flare-cell meter. Statistical analysis was performed to investigate the relationship between flare values and cell counts, and clinical parameters including patients' age, sex, duration of disease, best-corrected visual acuity, keratic precipitate, iris depigmentation, intraocular pressure, and posterior subcapsular lens opacities. RESULTS: Aqueous flare values (photon counts/ms) were significantly higher in Fuchs syndrome (9.40+/-5.85) than in normal controls (5.77+/-1.89, P=0.000). Aqueous cell counts (cells/0.5 mm(3)) were also significantly higher in Fuchs syndrome (5.09+/-4.84) than in normal controls (1.14+/-1.03, P=0.000). The flare values were positively correlated with the cell counts (r=0.331, P=0.001). Both flare values and cell counts were higher in eyes with keratic precipitates scored 2+ or 3+ as compared to those with a 1+ score. Higher flare values and cell counts were also observed in eyes with a 2+ or 3+ iris depigmentation score as compared to those with a 1+ score. No difference was found between flare values and cell counts and other parameters. CONCLUSION: Breakdown of blood-aqueous barriers and increased cell counts are present in the affected eyes in patients with Fuchs syndrome. These changes are positively associated with the degree of keratic precipitates and iris depigmentation.

[Disorders of the blood-aqueous barrier after phacoemulsification].

OBJECTIVE: To determine the status of blood-aqueous barrier after small incision phacoemulsification with implantation of foldable intraocular lens. METHODS: The blood-aqueous barrier status in 64 eyes of 60 patients who underwent cataract surgery was examined using a laser flare cell meter. The protein level of anterior chamber aqueous humor was evaluated by measurement of the flare value preoperatively and postoperatively. RESULTS: The mean preoperative flare intensity was (6.94 +/- 0.34) photon counts/ms, which increased to (26.27 +/- 1.37), (13.96 +/- 1.05), (9.07 +/- 0.43) and (7.16 +/- 0.27) photon counts/ms on days 1, 7, 30 and 90 after the surgery, respectively. Significantly statistical differences on flare values were found between preoperative data and those on days 1, 7 and 30 after surgery. The blood-aqueous barrier was recovered on day 90 postoperatively. The variables such as age, gender, eye (left/right) had no influence on the flare value. Patients with iris prolapse had a higher flare value at day 1 and day 7 after the surgery. CONCLUSIONS: Blood-aqueous barrier after phacoemulsification with implantation of intraocular lens can be measured quantitatively by the laser flare cell meter. The blood-aqueous barrier disorders can be recovered shortly after phacoemulsification.

Changes of blood aqueous barrier after phacoemulsification in rabbits.

PURPOSE: To evaluate the function and the morphological changes of the blood aqueous barrier (BAB) after phacoemulsification and to provide the physiological mechanism of BAB dysfunction. METHODS: Phacoemulsification was performed on 12 rabbit eyes. Aqueous humor was abstracted and the concentrations of aqueous humor protein were examined preoperatively and on postoperative days 1, 7, 14, 21, 30 with Lowry. After the iris and the ciliary body were removed from the rabbit eyes, we selected lanthanum nitrate as a tracer, then ultrastructural changes of BAB were investigated with transmission electron microscopy. RESULTS: Highly statistically significant differences (P < 0.05) were found between preoperative aqueous humor protein concentration and those measured on days 1, 7, 14, 21 and 30 after surgery. Under transmission electron microscopy, a part of the endothelial cells and BAB damaged as shown by the leakage of lanthanum tracing into intravessels through the broad space were observed. CONCLUSION: The results suggest that there is a blood aqueous barrier breakdown after phacoemulsification. The morphological basis of BAB damage is the reversible opening of tight junctions between endothelial cells.