METformin for the MINimization of Geographic Atrophy Progression (METforMIN): A Randomized Trial.

Purpose: Metformin use has been associated with a decreased risk of age-related macular degeneration (AMD) progression in observational studies. We aimed to evaluate the efficacy of oral metformin for slowing geographic atrophy (GA) progression. Design: Parallel-group, multicenter, randomized phase II clinical trial. Participants: Participants aged ≥ 55 years without diabetes who had GA from atrophic AMD in ≥ 1 eye. Methods: We enrolled participants across 12 clinical centers and randomized participants in a 1:1 ratio to receive oral metformin (2000 mg daily) or observation for 18 months. Fundus autofluorescence imaging was obtained at baseline and every 6 months. Main Outcome Measures: The primary efficacy endpoint was the annualized enlargement rate of the square root-transformed GA area. Secondary endpoints included best-corrected visual acuity (BCVA) and low luminance visual acuity (LLVA) at each visit. Results: Of 66 enrolled participants, 34 (57 eyes) were randomized to the observation group and 32 (53 eyes) were randomized to the treatment group. The median follow-up duration was 13.9 and 12.6 months in the observation and metformin groups, respectively. The mean ± standard error annualized enlargement rate of square root transformed GA area was 0.35 ± 0.04 mm/year in the observation group and 0.42 ± 0.04 mm/year in the treatment group (risk difference = 0.07 mm/year, 95% confidence interval = -0.05 to 0.18 mm/year; P = 0.26). The mean ± standard error decline in BCVA was 4.8 ± 1.7 letters/year in the observation group and 3.4 ± 1.1 letters/year in the treatment group (P = 0.56). The mean ± standard error decline in LLVA was 7.3 ± 2.5 letters/year in the observation group and 0.8 ± 2.2 letters/year in the treatment group (P = 0.06). Fourteen participants in the metformin group experienced nonserious adverse events related to metformin, with gastrointestinal side effects as the most common. No serious adverse events were attributed to metformin. Conclusions: The results of this trial as conducted do not support oral metformin having effects on reducing the progression of GA. Additional placebo-controlled trials are needed to explore the role of metformin for AMD, especially for earlier stages of the disease. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Vitreous Biomarkers for Proliferative Vitreoretinopathy Prognostication in Patients Undergoing Primary Retinal Detachment Repair.

Purpose: To compare baseline levels of exploratory biomarkers in the vitreous fluid of patients with primary retinal detachment who subsequently develop proliferative vitreoretinopathy (PVR) versus those who do not. Methods: In this exploratory case-control study, we evaluated the baseline protein biomarker levels from a biobank containing the vitreous fluid of patients who had undergone primary pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment. Undiluted samples were collected at the time of PPV and stored at -80°C. Samples from 13 patients who developed PVR within 6 months (PVR group) and 13 age- and gender-matched controls who did not develop PVR (control group) were included. Protein abundance levels were evaluated using a proximity extension assay, and a confirmatory enzyme-linked immunosorbent assay (ELISA) was used to measure the concentration of vimentin. Results: Baseline vimentin (Normalized Protein eXpression [NPX], 8.6 vs. 6.4, P < 0.0001) and heme oxygenase 1 (NPX 8.9 vs. 7.0, P < 0.001) levels were found to be elevated in vitreous fluid of patients who subsequently developed PVR compared to those who did not. Confirmatory analysis using ELISA demonstrated mean vimentin concentrations of 7254 vs. 2727 ng/mL in the PVR versus control groups (P = 0.0152). The odds ratio for developing PVR was 14 (confidence interval, 1.4-168; P = 0.03), assuming a baseline vimentin threshold of 7500 ng/mL. Conclusions: Vimentin is an intermediate filament protein expressed by retinal glial cells, and our data combined with prior evidence suggest that it may serve as an early vitreous biomarker for subsequent PVR formation and reactive gliosis. Furthermore, we found, for the first time, elevated baseline levels of heme oxygenase 1, a measurable indicator of oxidative stress. Translational Relevance: Our positive findings could impact clinical care for retinal detachment patients by facilitating risk stratification for targeted interventions or closer monitoring in those at the highest risk of developing PVR.

Association of Male Sex and Microvascular Alterations on Optical Coherence Tomography Angiography in Diabetes.

Purpose: Epidemiologically, men have a higher incidence, severity, and progression of diabetic retinopathy (DR) than women. We investigated microvascular differences between men and women with diabetes on optical coherence tomography angiography (OCTA). Methods: Three × 3 mm OCTA macula scans of non-diabetic and patients with diabetes were obtained. Vascular parameters included parafoveal vessel density (VD), vessel length density (VLD), and flow index (FI) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) as well as foveal avascular zone (FAZ) area and perimeter. Multivariable linear regression was used for statistical analysis. Results: There were 1809 patients with diabetes and 217 non-diabetic participants that were included in this study. Diabetic individuals included those with no DR (n = 1356), mild non-proliferative DR (NPDR; n = 286), moderate NPDR (n = 126), and severe NPDR/proliferative DR (PDR; n = 41). Male sex was significantly associated with smaller FAZ area/perimeter and lower DCP VLD in both non-diabetic subjects and patients with diabetes. Male sex in the diabetic group was additionally associated with lower SCP VD/VLD and DCP VD. Addition of an interaction between male sex and diabetes status in the interaction analysis showed that being male and diabetic conferred increased reduction in DCP VD and VLD compared to sex-based changes in non-diabetics. Larger FAZ perimeter, lower SCP VD/VLD, and lower DCP VLD were associated with poorer visual acuity in diabetics. Conclusions: On OCTA, male patients with diabetes may have more severe microvascular disease especially in the DCP compared to women. Translational Evidence: Sex-based alterations in diabetic microvascular disease has the potential to influence future basic and clinical studies as well as the implementation of OCTA disease markers.

Aqueous Fluid Transcriptome Profiling Differentiates Between Non-Neovascular and Neovascular AMD.

Purpose: Early and intermediate non-neovascular AMD (NN-AMD) has the potential to progress to either advanced NN-AMD with geographic atrophy, or to neovascular AMD (N-AMD) with CNV. This exploratory study performed an unbiased analysis of aqueous humor transcriptome in patients with early or intermediate NN-AMD vs. treatment-naïve N-AMD to determine the feasibility of using this method in future studies investigating pathways and triggers for conversion from one form to another. Methods: Aqueous humor samples were obtained from 20 patients with early or intermediate NN-AMD and 20 patients with untreated N-AMD, graded on clinical examination and optical coherence tomography. Transcriptome profiles were generated using next-generation sequencing methods optimized for ocular samples. Top-ranked transcripts were compared between groups, and pathway enrichment analysis was performed. Results: Seventy-eight differentially expressed transcripts were identified. Unsupervised clustering of differentially expressed transcripts was able to successfully differentiate between the two groups based on aqueous transcriptome alone. Pathway analysis highlighted changes in expression of genes associated with mitochondrial respiration, oxidative stress, ubiquitination, and neurogenesis between the two groups. Conclusions: This pilot study compared the aqueous fluid transcriptome of patients with early or intermediate NN-AMD and untreated N-AMD. Differences in transcripts and transcriptome pathways identified in the aqueous of patients with early or intermediate NN-AMD compared with patients with N-AMD are consistent with those previously implicated in the pathogenesis of these distinct AMD subtypes. The findings from this exploratory study warrant further investigation using a larger, prospective study design, with the inclusion of a control group of eyes without AMD.

Duration of Diabetes as a Risk Factor for Retinal Microvasculature Alterations Detected with Optical Coherence Tomography Angiography in Patients without Clinical Retinopathy.

In this study, we examined the impact of diabetes mellitus (DM) disease duration on optical coherence tomography angiography (OCTA) parameters in diabetic patients without diabetic retinopathy (DR). A total of 1118 eyes from 1118 DM patients without DR were divided into three groups by DM duration: 0−5 years (short cohort; n = 571), 6−10 years (medium cohort; n = 306), and >10 years (long cohort; n = 241). Ultra-widefield fundus photography and nine OCTA parameters derived from the superficial retinal capillary plexus were analyzed. Perfusion density (PD) and vessel length density (VD) were significantly decreased within the 1 mm patch in patient OCTAs from the medium cohort compared to the short cohort. Conversely, PD and VD were significantly decreased within the 6 mm patch and inner ring among the long cohort compared to the short and medium cohorts. These findings remained consistent after controlled analysis. Patients in the medium cohort had the largest FAZ area, while patients in the long cohort had the smallest FAZ area, with a statistically significant difference between the two groups. Superficial PD and VD significantly decreased among the medium and long cohorts compared to the short cohort, confirming that subclinical, progressive macular vasculature change is associated with longer DM duration. However, while FAZ area significantly increased in the medium cohort, the long cohort exhibited decreased FAZ area, suggesting the latter may possess protective factors that decrease overall risk of DR development.

Male sex increases the risk of diabetic retinopathy in an urban safety-net hospital population without impacting the relationship between axial length and retinopathy.

This study sought to assess the association between axial length (AL) and diabetic retinopathy (DR) in a diverse cohort of patients and to investigate the impact of sex on this relationship. An urban safety net hospital database was used for this cross-sectional observational study. Diabetic patients who underwent fundus photography and AL measurement between March 2017 and June 2020 were included. The fundus photographs were graded following the Early Treatment of Diabetic Retinopathy Study criteria. The study enrolled 1843 patients with diabetes (mean age: 56.9 ± 12.1 years; AL: 23.56 ± 1.12 mm), including 931 men and 912 women. Male sex was a risk factor for diabetic retinopathy (P = 0.001; odds ratio [OR] 1.5, 95% confidence interval [CI] 1.18-1.98). A higher DR prevalence was associated with shorter AL both in men (P = 0.003; OR 0.77; 95% CI 0.66-0.91) and women (P = 0.02; OR 0.83; 95% CI 0.71-0.97) after adjusting for systemic risk factors using multivariable logistic regression. There was no significant impact of sex on the relationship between AL and DR (P = 0.56). In the subset of patients with asymmetric DR, the percentage of patients whose shorter eye had a higher stage of DR was not significantly different between men and women (P = 0.20). Male sex is a risk factor for DR in a diverse safety-net hospital population. Longer AL is associated with a lower risk of DR, and this relationship is not affected by sex.

Validation of a Multi-Sensor-Based Kiosk in the Use of the Short Physical Performance Battery in Older Adults Attending a Fall and Balance Clinic.

BACKGROUND: The Short Physical Performance Battery (SPPB) is a well-established functional assessment tool used for the screening and assessment of frailty and sarcopenia. However, the SPPB requires trained staff experienced in conducting the standardized protocol, which may limit its widespread use in clinical settings. The automated SPPB (eSPPB) was developed to address this potential barrier; however, its validity among frail older adults remains to be established. Therefore, this exploratory study compared the eSPPB and manual SPPB in patients attending a tertiary fall clinic in relation to their construct validity, reliability, and agreement. METHODS: We studied 37 community-dwelling older adults (mean age, 78.5±6.8 years; mean FRAIL score, 1.2±1.0; 65% pre-frail) attending a tertiary falls clinic. The participants used the mSPPB and eSPPB simultaneously. We evaluated the convergent validity, discriminatory ability, reliability, and agreement using partial correlation adjusted for age and sex, an SPPB cutoff of ≤8 to denote sarcopenia, intraclass correlation coefficients (ICC), and Bland-Altman plots, respectively. RESULTS: The eSPPB showed strong correlations with the mSPPB (r=0.933, p<0.01) and Berg Balance Scale (r=0.869, p<0.01), good discriminatory ability for frailty and balance, and good to excellent reliability (ICC=0.94; 95% confidence interval, 0.88-0.97). The Bland-Altman plots indicated good agreement with the mSPPB (mean difference, -0.2; 95% confidence interval, -3.2-2.9) without evidence of systematic or proportional biases. CONCLUSION: The results of our exploratory study corroborated the construct validity, reliability, and agreement of the eSPPB with the mSPPB in a small sample of predominantly pre-frail older adults with increased fall risk. Future studies should examine the scalability and feasibility of the widespread use of the eSPPB for frailty and sarcopenia assessment.

Association between smoking history and optical coherence tomography angiography findings in diabetic patients without diabetic retinopathy.

PURPOSE: To investigate any associations between cigarette smoking and retinal microvascular changes in diabetic patients without visible retinopathy. DESIGN: Retrospective, cross-sectional study. PARTICIPANTS: 1099 eyes from 1099 diabetic patients with no clinical evidence of diabetic retinopathy (DR) were included in this study. METHODS: Diabetic patients underwent optical coherence tomography angiography (OCTA) scanning at Zuckerberg San Francisco General Hospital and Trauma Center between April 2018 and September 2019. Patient demographic and clinical information was collected. Standard bivariate statistics and multivariate linear regression were performed. MAIN OUTCOME MEASURES: OCTA parameters included metrics related to the foveal avascular zone (FAZ; area, perimeter, circularity), perfusion density (PD; full, center, inner), and vessel length density (VLD; full, center, inner). RESULTS: The study population included 750 non-smokers and 349 smokers. FAZ perimeter was the only OCTA parameter that was significantly different between the two groups on uncontrolled analysis (P = 0.033). Multivariate regression analyses revealed significant associations between lower VLD full (ß = -0.31, P = 0.048), lower VLD inner (ß = -0.35, P = 0.046) and a history of smoking. No significant associations between cigarette smoking and either FAZ or PD were detected. CONCLUSIONS: Our results suggest that smoking is likely associated with deleterious changes in the retinal microvasculature of patients with a history of diabetes and no visible DR. Based on these findings, diabetic patients with a history of smoking may benefit from higher prioritization in terms of ophthalmic screening.

Identification of 22 susceptibility loci associated with testicular germ cell tumors.

Testicular germ cell tumors (TGCT) are the most common tumor in young white men and have a high heritability. In this study, the international Testicular Cancer Consortium assemble 10,156 and 179,683 men with and without TGCT, respectively, for a genome-wide association study. This meta-analysis identifies 22 TGCT susceptibility loci, bringing the total to 78, which account for 44% of disease heritability. Men with a polygenic risk score (PRS) in the 95th percentile have a 6.8-fold increased risk of TGCT compared to men with median scores. Among men with independent TGCT risk factors such as cryptorchidism, the PRS may guide screening decisions with the goal of reducing treatment-related complications causing long-term morbidity in survivors. These findings emphasize the interconnected nature of two known pathways that promote TGCT susceptibility: male germ cell development within its somatic niche and regulation of chromosomal division and structure, and implicate an additional biological pathway, mRNA translation.

Sex-Based Analysis of Potential Inflammation-Related Protein Biomarkers in the Aqueous Humor of Patients With Diabetes Mellitus.

Purpose: To investigate whether men have higher inflammatory protein biomarker concentrations in their aqueous humor (AH) compared with women in groups of patients with varying levels of diabetic disease. Methods: This cross-sectional study included AH specimens from 59 adult patients comprised of three groups: no diabetes mellitus (DM), DM without diabetic retinopathy (DR), and DM with proliferative diabetic retinopathy (PDR). Protein biomarker concentration values were quantified using a commercial proximity extension assay-based technique. Results: Intersex comparisons of concentration values for each protein biomarker revealed no discoveries in patients with no DM or with PDR. In contrast, 24 discoveries were detected in patients with DM without DR. The mean concentration value for all 24 protein biomarkers was higher in men compared with women. Of these 24 proteins, 12 demonstrated a significant association with sex on multivariate linear regression analysis. The ß coefficient results demonstrated a positive association between male sex and concentration value for all 12 of these proteins. Conclusions: Higher AH concentration levels of several potential biomarkers, including chemokines, proteases, proteins involved in programmed cell death, and a T-cell surface protein, were detected in men with DM with no DR. These findings suggest that men may have a more inflammatory disease phenotype compared with women in this group of patients. Translational Relevance: The findings of this study help explain differences in epidemiologic patterns of diabetic retinopathy development between men and women.

Discordant vascular parameter measurements in diabetic and non-diabetic eyes detected by different optical coherence tomography angiography devices.

PURPOSE: To compare quantitative changes in macular parameters in diabetic patients detected by two optical coherence tomography angiography (OCTA) instruments. METHODS: 80 phakic eyes were classified as no diabetes, diabetes without diabetic retinopathy (DR), mild non-proliferative diabetic retinopathy (NPDR), and severe NPDR or proliferative DR (PDR). OCTA was performed using devices from two manufacturers (Zeiss and Heidelberg). Superficial and deeper vascular skeleton density (SVSD, DVSD), superficial and deeper vessel area density (SVAD, DVAD), choriocapillaris flow voids (CCFV), and choroidal flow voids (CFV) were calculated. Inter-device comparisons were performed using the size comparison index (SCI) and the discrepancy index (DI). RESULTS: The two devices were inconsistent in SVSD, DVSD, DVAD, CCFV and CFV parameters (all P < 0.05). In addition, the SCI was positive for DVAD (all P < 0.001) and negative for SVSD, DVSD, CCFV and CFV in all groups (all P <0.001), except for DVSD in severe NPDR or PDR. The discrepancy index was not significantly different among groups for SVD, SPD, DVD, DPD and CFV (all P> 0.05). The mean DI of CCFV was statistically different between the four groups (P < 0.001). CONCLUSIONS: The two instruments were largely inconsistent in the measurement of macular parameters relevant to DR. The choice of imaging device can impact OCTA analytics and should be taken into account when drawing conclusions about DR-related changes.

PolyC-binding proteins enhance expression of the CDK2 cell cycle regulatory protein via alternative splicing.

The PolyC binding proteins (PCBPs) impact alternative splicing of a subset of mammalian genes that are enriched in basic cellular functions. Here, we focus our analysis on PCBP-controlled cassette exon-splicing within the cell cycle control regulator cyclin-dependent kinase-2 (CDK2) transcript. We demonstrate that PCBP binding to a C-rich polypyrimidine tract (PPT) preceding exon 5 of the CDK2 transcript enhances cassette exon inclusion. This splice enhancement is U2AF65-independent and predominantly reflects actions of the PCBP1 isoform. Remarkably, PCBPs' control of CDK2 ex5 splicing has evolved subsequent to mammalian divergence via conversion of constitutive exon 5 inclusion in the mouse CDK2 transcript to PCBP-responsive exon 5 alternative splicing in humans. Importantly, exclusion of exon 5 from the hCDK2 transcript dramatically represses the expression of CDK2 protein with a corresponding perturbation in cell cycle kinetics. These data highlight a recently evolved post-transcriptional pathway in primate species with the potential to modulate cell cycle control.

Recombinant thrombomodulin improves the visceral microcirculation by attenuating the leukocyte-endothelial interaction in a rat LPS model.

INTRODUCTION: Abnormalities in vascular endothelial function play an important role in the development of septic organ dysfunction. The aim of this study was to examine the effect of recombinant thrombomodulin (rTM) on leukocyte-endothelial interaction and subsequent malcirculation in endotoxemia. MATERIALS AND METHODS: Wistar rats were administered with either low, medium or high dose of rTM (n=7 each) 2hours after lipopolysaccharide (LPS) infusion. Mesenteric microcirculation after the treatment was observed under the intravital microscopy. In another series (n=5 each), plasma levels of high-mobility group box 1 (HMGB1) levels were measured at 5hours after LPS infusion. RESULTS: Microscopic findings revealed suppression in leukocyte adhesion, thrombus formation and endothelial damage with the treatment by rTM. However, high-dose rTM tended to increase the bleeding events. Thus, blood flow was better maintained with medium-dose rTM (P<0.05). The increase in HMGB1 level was significantly suppressed by medium and high-dose rTM (P<0.05, respectively). CONCLUSIONS: rTM demonstrated a protective effect on microcirculation through the inhibition of leukocyte-endothelial interaction and suppression of HMGB1.