Association of Intermediate-Stage Age-Related Macular Degeneration with Plasma Inflammatory Biomarkers in Persons with AIDS

Purpose

To evaluate associations of plasma levels of inflammatory biomarkers with age-related macular degeneration (AMD) and cataract in persons with AIDS.

Design

Nested case-control study (analysis 1) and nested cohort study (analysis 2).

Participants

Analysis 1: persons with AIDS and incident intermediate-stage AMD (n = 26) and controls without AMD matched for age, race/ethnicity, and gender (n = 49) from The Longitudinal Study of Ocular Complications of AIDS. Analysis 2: 475 persons from LSOCA with baseline plasma biomarker levels followed prospectively for cataract.

Methods

In both analyses, cryopreserved plasma specimens obtained at baseline were assayed for monocyte chemoattractant protein (MCP)-1 (CC motif chemokine ligand [CCL] 2), macrophage inflammatory protein (MIP)-1β (CCL4), soluble tumor necrosis factor receptor (sTNFR) 2, interleukin (IL)-18, and fractalkine (CX3 motif chemokine ligand 1 [CX3CL1]).

Main Outcome Measures

Analysis 1: mean difference (cases - controls) in plasma biomarker levels. Analysis 2: incident cataract.

Results

After adjusting for plasma human immunodeficiency virus RNA level, CD4+ T-cell count, and smoking, elevated baseline plasma levels of sTNFR2 and IL-18 (mean differences [cases - controls] 0.11 log10[pg/mL]; 95% confidence interval [CI], 0.01-0.20; P = 0.024 and 0.13 log10[pg/mL]; 95% CI, 0.01-0.24; P = 0.037, respectively) each were associated with incident AMD. In a competing risk (with mortality) analysis, elevated baseline standardized log10 plasma levels of MCP-1, sTNFR2, IL-18, and fractalkine each were associated with a decreased cataract risk.

Conclusions

When combined with previous data suggesting that AMD is associated with elevated plasma levels of C-reactive protein, soluble CD14, and possibly IL-6, the association of elevated plasma levels of sTNFR2 and IL-18 with incident AMD, but not with incident cataract, suggests that innate immune system activation, and possibly NLRP3 inflammasome activation, may play a role in the pathogenesis of AMD in this population.

Financial Disclosures

The authors have no proprietary or commercial interest in any materials discussed in this article.

Association of elevated plasma inflammatory biomarker levels with age-related macular degeneration but not cataract in persons with AIDS

OBJECTIVE

To evaluate the relationship between plasma biomarkers of systemic inflammation and incident age-related macular degeneration (AMD) in persons with the AIDS.

DESIGN

Case-control study.

METHODS

Participants with incident intermediate-stage AMD (N = 26) in the Longitudinal Study of the Ocular Complications of AIDS (LSOCA) and controls (N = 60) without AMD. Cryopreserved baseline plasma specimens were assayed for biomarkers of inflammation, including high-sensitivity C-reactive protein (CRP), interleukin (IL)-6, interferon-γ inducible protein (IP)-10, soluble CD14 (sCD14), soluble CD163 (sCD163), and intestinal fatty acid-binding protein (I-FABP).

RESULTS

After adjustment for age, sex, and race/ethnicity, baseline mean ± standard deviation (SD) log10(mg/ml) plasma levels of CRP (0.52 ± 0.60 vs. 0.20 ± 0.43; P = 0.01) and mean ± SD log10(pg/ml) plasma levels of sCD14 (6.31 ± 0.11 vs. 6.23 ± 0.14; P = 0.008) were significantly higher among cases (incident AMD) than among controls (no AMD). There was a suggestion that mean ± SD baseline log10(pg/ml) plasma IL-6 levels (0.24 ± 0.33 vs. 0.11 ± 0.29; P = 0.10) might be higher among cases than controls. In a separate analysis of 548 participants in LSOCA, elevated baseline levels of plasma inflammatory biomarkers were associated with a greater risk of mortality but not with an increased risk of incident cataract.

CONCLUSION

These data suggest that systemic inflammatory biomarkers are associated with incident AMD but not incident cataract in persons with AIDS, and that systemic inflammation may play a role in the pathogenesis of AMD.

Association of Systemic Inflammation With Retinal Vascular Caliber in Patients With AIDS

Purpose

To evaluate relationships among retinal vascular caliber and biomarkers of systemic inflammation in patients with AIDS.

Methods

A total of 454 participants with AIDS had retinal vascular caliber (central retinal artery equivalent and central retinal vein equivalent) determined from enrollment retinal photographs by reading center graders masked to clinical and biomarker information. Cryopreserved plasma specimens were assayed for inflammatory biomarkers, including C-reactive protein (CRP), IL-6, interferon-γ inducible protein (IP)-10, kynurenine/tryptophan (KT) ratio, and intestinal fatty acid binding protein (I-FABP).

Results

In the simple linear regression of retinal vascular caliber on plasma biomarkers, elevated CRP, IL-6, and IP-10 were associated with retinal venular dilation, and elevated KT ratio with retinal arteriolar narrowing. In the multiple linear regression, including baseline characteristics and plasma biomarkers, AMD was associated with dilation of retinal arterioles (mean difference: 9.1 μm; 95% confidence interval [CI] 5.2, 12.9; P < 0.001) and venules (mean difference, 10.9 μm; 95% CI, 5.3, 16.6; P < 0.001), as was black race (P < 0.001). Hyperlipidemia was associated with retinal venular narrowing (mean difference, -7.5 μm; 95% CI, -13.7, -1.2; P = 0.02); cardiovascular disease with arteriolar narrowing (mean difference, -5.2 μm; 95% CI, -10.3, -0.1; P = 0.05); age with arteriolar narrowing (slope, -0.26 μm/year; 95% CI, -0.46, -0.06; P = 0.009); and IL-6 with venular dilation (slope, 5.3 μm/standard deviation log10[plasma IL-6 concentration]; 95% CI, 2.7, 8.0; P < 0.001).

Conclusions

These data suggest that retinal vascular caliber is associated with age, race, AMD, hyperlipidemia, cardiovascular disease, and selected biomarkers of systemic inflammation.

Association of Retinal Vascular Caliber and Age-Related Macular Degeneration in Patients With the Acquired Immunodeficiency Syndrome

Purpose

To evaluate the relationship between retinal vascular caliber and AMD in patients with AIDS.

Methods

Participants enrolled in the Longitudinal Study of the Ocular Complications of AIDS had retinal photographs taken at enrollment. Retinal vascular caliber (central retinal artery equivalent [CRAE] and central retinal vein equivalent [CRVE]) and intermediate-stage AMD were determined from these retinal photographs. Photographs were evaluated by graders at a centralized reading center, using the Age-Related Eye Disease Study grading system for AMD and semiautomated techniques for evaluating retinal vascular caliber.

Results

Of the 1171 participants evaluated, 110 (9.4%) had AMD and 1061 (90.6%) did not. Compared with participants without AMD, participants with AMD had larger mean CRAEs (151 ± 16 μm versus 147 ± 16 μm; P = 0.009) and mean CRVEs (228 ± 24 μm versus 223 ± 25 μm; P = 0.02). The unadjusted differences were: CRAE, 4.3 μm (95% confidence interval [CI] 1.1-7.5; P = 0.009) and CRVE, 5.5 μm (95% CI 0.7-10.3; P = 0.02). After adjustment for age, race/ethnicity, sex, human immunodeficiency syndrome (HIV) transmission category, smoking, enrollment and nadir CD4+ T cells, and enrollment and maximum HIV load, the differences between patients with and without AMD were as follows: CRAE, 5.4 μm (95% CI 2.3-8.5; P = 0.001) and CRVE, 6.0 μm (95% CI 1.4-10.6; P = 0.01).

Conclusions

In patients with AIDS, AMD is associated with greater retinal arteriolar and venular calibers, suggesting a role for shared pathogenic mechanisms, such as persistent systemic inflammation.

Incidence of Intermediate-stage Age-related Macular Degeneration in Patients With Acquired Immunodeficiency Syndrome

PURPOSE

To evaluate the incidence of intermediate-stage age-related macular degeneration (AMD) in patients with acquired immunodeficiency syndrome (AIDS).

DESIGN

Cohort study.

METHODS

Patients enrolled in the Longitudinal Study of the Ocular Complications of AIDS (LSOCA) underwent 5- and 10-year follow-up retinal photographs. Intermediate-stage AMD (AREDS stage 3) was determined from these photographs by graders at a centralized Reading Center, using the Age-Related Eye Disease Study-2 grading system. The incidence of AMD in LSOCA was compared with that in the Multi-Ethnic Study of Atherosclerosis (MESA), a Human Immunodeficiency Virus (HIV)-uninfected cohort, which used a similar photographic methodology.

RESULTS

The incidence of AMD in LSOCA was 0.65/100 person-years (PY). In a multivariate analysis the only significant risk factor for AMD in LSOCA was smoking; the relative risk vs never-smokers was 3.4 for former smokers (95% confidence interval [CI] 1.3, 9.5; P = .02) and 3.3 for current smokers (95% CI 1.1, 9.7; P = .03). Compared with the MESA cohort, the race/ethnicity- and sex-adjusted risk of AMD in LSOCA was 1.75 (95% CI 1.16, 2.64; P = .008), despite the fact that the mean age of the MESA cohort was 17 years greater than the LSOCA cohort (61 ± 9 years vs 44 ± 8 years).

CONCLUSIONS

Patients with AIDS have a 1.75-fold increased race- and sex-adjusted incidence of intermediate-stage AMD compared with that found in an HIV-uninfected cohort. This increased incidence is consistent with the increased incidence of other age-related diseases in antiretroviral-treated, immune-restored, HIV-infected persons when compared with HIV-uninfected persons.

Immune reconstitution inflammatory syndrome in a HIV-infected patient with disseminated tuberculosis

Immune reconstitution inflammatory syndrome (IRIS) is the paradoxical worsening of pre-existing infectious processes after commencement of anti-retroviral therapy (ART) in HIV-infected patients. Its manifestations are dependent on the underlying opportunistic infections. We report a case of an HIV-infected patient with disseminated tuberculosis, who responded to anti-tuberculosis therapy but suffered from paradoxical worsening after commencement of ART.

Dissociations of the Fluocinolone Acetonide Implant: The Multicenter Uveitis Steroid Treatment (MUST) Trial and Follow-up Study

PURPOSE

To describe fluocinolone acetonide implant dissociations in the Multicenter Uveitis Steroid Treatment (MUST) Trial.

DESIGN

Randomized clinical trial with extended follow-up.

METHODS

Review of data collected on the first implant in the eye(s) of participants. Dissociation was defined as the drug pellet no longer being affixed to the strut and categorized as spontaneous or surgically related.

RESULTS

A total of 250 eyes (146 patients) had at least 1 implant placed. Median follow-up time after implant placement was 6 years (range 0.5-9.2 years). Thirty-four dissociations were reported in 30 participants. There were 22 spontaneous events in 22 participants; 6-year cumulative risk of a spontaneous dissociation was 4.8% (95% confidence interval [CI]: 2.4%-9.1%). The earliest event occurred 4.8 years after placement. Nine of 22 eyes with data had a decline in visual acuity ≥5 letters temporally related to the dissociation. Thirty-nine implant removal surgeries were performed, 33 with replacement. Twelve dissociations were noted during implant removal surgeries in 10 participants (26%, 95% CI 15%-48%); 5 of these eyes had a decline in visual acuity ≥5 letters after surgery. The time from implant placement to removal surgery was longer for the surgeries at which dissociated implants were identified than for those without one (5.7 vs 3.7 years, P < .001). Overall, visual acuity declined 15 or more letters from pre-implant values in 22% of affected eyes; declines were frequently associated with complications of uveitis or its treatment.

CONCLUSION

There is an increasing risk of dissociation of Retisert implants during follow-up; the risk is greater with removal/exchange surgeries, but the risk of both spontaneous and surgically related events increases with longevity of the implants. In 22% of affected eyes visual acuity declined by 15 letters. In the context of eyes with moderate to severe uveitis for years, this rate is not unexpected.

Relationship of retinal vascular calibre and diabetic retinopathy in Chinese patients with type 2 diabetes mellitus: the Desheng Diabetic Eye Study

AIMS

To describe the relationship of retinal arteriolar and venular calibre with diabetic retinopathy (DR) and related risk factors, including glucose levels and other biomarkers in a Chinese population with type 2 diabetes mellitus (T2DM).

METHODS

A cross-sectional study. Patients with T2DM were recruited from a local community in urban Beijing. Seven fields 30° colour fundus photographs were taken and examined for the presence and severity of DR using a standardised grading system. Retinal vascular calibres were measured and expressed as average central retinal arteriolar and venular equivalent using a computer-based program.

RESULTS

A total of 1340 patients with T2DM were included for analysis. Of these, 472 (35.22%) had DR. Wider retinal venular calibre, but not arteriolar calibre, was associated with increasing glucose and glycosylated haemoglobin A1c levels (p<0.006) and dyslipidaemia (p for trend <0.05). After adjusting for possible covariates, the higher quartile of retinal venular calibre was associated with higher prevalence of any DR (OR 2, 95% CI 1.36 to 2.95). Venular calibre increased from 224.33 μm in those without retinopathy to 231.21 μm in those with mild, 241.01 μm in those with moderate and 235.65 μm in those with severe retinopathy (p for trend <0.001). Arteriolar calibre was not associated with DR.

CONCLUSIONS

In the current study, wider venular calibre, but not arteriolar calibre, was shown to be associated with development and increased severity of DR independently from other risk factors in a Chinese diabetic population.

Prevalence of intermediate-stage age-related macular degeneration in patients with acquired immunodeficiency syndrome

PURPOSE

To evaluate the prevalence of intermediate-stage age-related macular degeneration (AMD) in patients with acquired immunodeficiency syndrome (AIDS).

DESIGN

Cross-sectional study of patients with AIDS enrolled in the Longitudinal Study of the Ocular Complications of AIDS.

METHODS

Intermediate-stage AMD was determined from enrollment retinal photographs by graders at a centralized Reading Center, using the Age-Related Eye Disease Study grading system. Graders were masked as to clinical data.

RESULTS

Of 1825 participants with AIDS and no ocular opportunistic infections, 9.9% had intermediate-stage AMD. Risk factors included age, with an odds ratio (OR) of 1.9 (95% confidence interval [CI] 1.6, 2.3, P < .001) for every decade of age; the prevalence of AMD ranged from 4.0% for participants 30-39 years old to 24.3% for participants ≥60 years old. Other risk factors included the human immunodeficiency virus (HIV) risk groups of injection drug use (OR = 2.4, 95% CI 1.5, 3.9, P < .001) or heterosexual contact (OR = 1.9, 95% CI 1.3, 2.8, P = .001). Compared with the HIV-uninfected population in the Beaver Dam Offspring Study, there was an approximate 4-fold increased age-adjusted prevalence of intermediate-stage AMD.

CONCLUSIONS

Patients with AIDS have an increased age-adjusted prevalence of intermediate-stage AMD compared with that found in a non-HIV-infected cohort evaluated with similar methods. This increased prevalence is consistent with the increased prevalence of other age-related diseases in antiretroviral-treated, immune-restored, HIV-infected persons when compared to non-HIV-infected persons.

Affinity selection of DNA-binding proteins from yeast genomic DNA libraries by improved lambda phage display vector

Phage display is a useful means of identifying and selecting proteins of interest that bind specific targets. In order to examine the potential of phage display for the genome-wide screening of DNA-binding proteins, we constructed yeast genomic libraries using lambda foo-based vectors devised in this work. After affinity selection using GAL4 UAS(G) as a probe, phages expressing GAL4 were enriched approximately 5 x 10(5)-fold from the library. Approximately 90% of polypeptides encoded in correct translation reading frames by the selected phages were known or putative polynucleotide-binding proteins. This result clearly indicates that the modified lambda phage display vector in combination with our enrichment technique has great potential for the enrichment of DNA-binding proteins in a sequence-specific manner.

Transformation of 2,4,6-trinitrotoluene by purified xenobiotic reductase B from Pseudomonas fluorescens I-C

The enzymatic transformation of 2,4,6-trinitrotoluene (TNT) by purified XenB, an NADPH-dependent flavoprotein oxidoreductase from Pseudomonas fluorescens I-C, was evaluated by using natural abundance and [U-(14)C]TNT preparations. XenB catalyzed the reduction of TNT either by hydride addition to the aromatic ring or by nitro group reduction, with the accumulation of various tautomers of the protonated dihydride-Meisenheimer complex of TNT, 2-hydroxylamino-4,6-dinitrotoluene, and 4-hydroxylamino-2, 6-dinitrotoluene. Subsequent reactions of these metabolites were nonenzymatic and resulted in predominant formation of at least three dimers with an anionic m/z of 376 as determined by negative-mode electrospray ionization mass spectrometry and the release of approximately 0.5 mol of nitrite per mol of TNT consumed. The extents of the initial enzymatic reactions were similar in the presence and in the absence of O(2), but the dimerization reaction and the release of nitrite were favored under aerobic conditions or under anaerobic conditions in the presence of NADP(+). Reactions of chemically and enzymatically synthesized and high-pressure liquid chromatography-purified TNT metabolites showed that both a hydroxylamino-dinitrotoluene isomer and a tautomer of the protonated dihydride-Meisenheimer complex of TNT were required precursors for the dimerization and nitrite release reactions. The m/z 376 dimers also reacted with either dansyl chloride or N-1-naphthylethylenediamine HCl, providing evidence for an aryl amine functional group. In combination, the experimental results are consistent with assigning the chemical structures of the m/z 376 species to various isomers of amino-dimethyl-tetranitrobiphenyl. A mechanism for the formation of these proposed TNT metabolites is presented, and the potential enzymatic and environmental significance of their formation is discussed.

Affinity selection of DNA-binding proteins displayed on bacteriophage lambda

Two transcription factors, human ATF1, its DNA-binding domain (ATF1BD), and the DNA-binding domain (GAL4BD) of the yeast GAL4 protein, were displayed on the surface of bacteriophage lambda vectors and efficiently selected by DNA fragments immobilized in microtiter wells. The DNA-binding proteins are fused to the carboxy terminus of the tail protein gpV and head protein gpD of the vectors, lambdafoo and lambdafooDc, respectively. After a single round of affinity selection, the fusion phages were successfully enriched 60- to 4,000-fold over the vector phages. Further, the GAL4BD fusion phages were enriched 5- and 15-fold by affinity selection using specific DNA as probes over nonspecific DNA when expressed on lambdafooDc and lambdafoo, respectively. The ATF1BD fusion phages were also sequence-specifically enriched greater than 4-fold when displayed on lambdafoo. These results suggest that the lambdafoo display system is useful for in vitro studying of protein-DNA interactions and may be applied to screening of DNA-binding protein from complex cDNA libraries through DNA-binding affinity.

A symbiont-produced protein and bacterial symbiosis in Amoeba proteus

Gram symbiotic X-bacteria present in the xD strain of Amoeba proteus as required cell components, synthesize and export a large amount of a 29-kDa protein (S29x) into the host's cytoplasm across bacterial and symbiosome membranes. The S29x protein produced by E. coli transformed with the s29x gene is also rapidly secreted into the culture medium. Inside amoebae, S29x enters the host's nucleus as detected by confocal and immunoelectron microscopy, although it is not clear if S29x is selectively accumulated inside the nucleus. The deduced amino-acid sequence of S29x has a stretch of basic amino acids that could act as a nuclear localization signal, but there is no signal peptide at the N-terminus and the transport of S29x is energy independent. The functions of S29x are not known, but in view of its prominent presence inside the amoeba's nucleus, S29x is suspected to be involved in affecting the expression of amoeba's nuclear gene(s).

The s29x gene of symbiotic bacteria in Amoeba proteus with a novel promoter

Gram-symbiotic bacteria (called X-bacteria), present in the xD strain of Amoeba proteus as required cell components, synthesize and export a large amount of a 29-kDa protein, S29x. S29x is exported into the host's cytoplasm across the bacterial membranes and the symbiosome membrane. The complete nucleotide (nt) sequence of the s29x gene of X-bacteria has been determined, and the promoter sequence and tsp have also been identified. The gene has a nonconventional promoter with putative nt sequences different from the known consensus sequences. When Escherichia coli cells are transformed with s29x, the gene is expressed and the product is secreted into the culture medium. Functions of S29x are not fully known, but it is suspected that S29x plays an important role in the symbiotic relationship between amoebae and X-bacteria.