Isolation of three different sizes of exosomes in an Asian population with different retinal diseases before and after treatment: preliminary results

Exosomes are membranous structures measuring between 40-120 nm that are secreted by various cells of the human body into the body fluid system. Exosomes contain proteins, mRNA, miRNA, and signaling molecules, and physiologically they assist in the intercellular transport of proteins and RNA molecules. In this study, we used an immunoaffinity filter paper platform combined with scanning electron microscopy and microfluidic systems to detect the size of exosomes within the aqueous humor. Eight aqueous humor samples showed three distinct sizes of exosomes that were significantly different on scanning electron microscopy(P < 0.01). We further used nanoparticle tracking analysis to assess the size distribution of exosomes within the aqueous humor. We found significantly different distributions of exosomes between patients with three different ocular diseases and patients with normal cataracts as controls. An obvious peak of exomeres(size around 35 nm)was found in the patients with central retinal vein occlusion and vitreous hemorrhage. Flare-ups of large exosomes(size 90-120 nm)were found in the patients with the inflammatory ocular disease pars planitis. No obvious peaks in exomeres or large exosomes were found in the control group. There was a high association between the distribution of exosomes and the pathogenesis of ocular diseases. After intravitreal anti-vascular endothelial growth factor treatment, the aqueous humor from the patients with neovascular diseases showed a significant reduction in exosomes in nanoparticle tracking analysis. These findings suggest that at least three distinct sizes of exosomes exist in the aqueous humor:(1)exomeres:<35 nm;(2)small exosomes:60-80 nm; and (3)large exosomes:90-120 nm. Different sizes of exosomes may have different implications in normal or diseased eyes.

The protective effects of beta-mangostin against sodium iodate-induced retinal ROS-mediated apoptosis through MEK/ERK and p53 signaling pathways

Previous studies have indicated that NaIO3 induces intracellular reactive oxygen species (ROS) production and has been used as a model for age-related macular degeneration (AMD) due to the selective retinal pigment epithelium (RPE) cell damage it induces. Beta-mangostin (BM) is a xanthone-type natural compound isolated from Cratoxylum arborescens. The influence of BM on NaIO3-induced oxidative stress damage in ARPE-19 cells has not yet been elucidated. In this study, we investigated how BM protects ARPE-19 cells from NaIO3-induced ROS-mediated apoptosis. Our results revealed that BM notably improved cell viability and prevented ARPE-19 cell mitochondrial dysfunction mediated-apoptosis induced by NaIO3; it was mediated by significantly reduced NaIO3-upregulated ROS, cellular H2O2 production and improved downregulated glutathione and catalase activities. Furthermore, we found that BM could suppress the expression of Bax, cleaved PARP, and cleaved caspase-3 by decreasing phosphorylation of MEK/ERK and p53 expression in NaIO3-induced ARPE-19 cells. At the same time, we also used MEK inhibitors (PD98059) to confirm the above phenomenon. Moreover, our animal experiments revealed that BM prevented NaIO3 from causing retinal deformation; it led to thicker outer and inner nuclear layers and downregulated cleaved caspase-3 expression compared to the group receiving NaIO3 only. Collectively, these results suggest that BM can protect the RPE and retina from NaIO3-induced apoptosis through ROS-mediated mitochondrial dysfunction involving the MEK/ERK and p53 signaling pathways.

Tinnitus as a Potential Risk Factor for Uveitis: A 14-Year Nationwide Population-Based Cohort Study in Taiwan

BACKGROUND

Tinnitus and uveitis have shared commonality in pathophysiology in terms of autoimmunity. However, no studies that have linked any association between the conditions of tinnitus and uveitis.

METHODS

This is a retrospective study conducted from the Taiwan National Health Insurance database in order to investigate whether tinnitus patients are at increased risk of uveitis. Patients newly diagnosed with tinnitus between 2001 and 2014 were recruited and followed up until 2018. The endpoint of interest was a diagnosis of uveitis.

RESULTS

A total of 31,034 tinnitus patients and 124,136 matched comparisons were analyzed. Tinnitus patients were found to have a significantly higher cumulative incidence for uveitis than those without the diagnosis of tinnitus with incidence rate of 1.68 (95% CI 1.55-1.82) per 10 000 person-months for tinnitus group and 1.48 (95% CI 1.42-1.54) per 10 000 person-months for non-tinnitus group.

CONCLUSION

Tinnitus patients were found to have increased risk of developing uveitis.

Small intestine submucosa as a growth factor attractor promotes peripheral nerve regeneration by enhancing syndecan-3/glial cell line-derived neurotrophic factor (GDNF) signalling: in vivo study

Peripheral nerve regeneration (PNR) following trauma requires the reconstruction of the extracellular matrix (ECM) and the proper stimulation of growth factors. Decellularized small intestine submucosa (SIS) has been extensively used as an ECM scaffold for tissue repair, but its potential to enhance the effects of exogenous growth factors on PNR is not well understood. In this study, we evaluated the effects of SIS implantation combined with glial cell-derived growth factor (GDNF) treatment on PNR in a rat neurorrhaphy model. We found that both SIS and regenerating nerve tissue expressed syndecan-3 (SDC3), one of major heparan sulphate proteoglycans (HSPG) in nerve tissue, and that SDC3 interacted with GDNF in the regenerating nerve tissue. Importantly, the SIS-GDNF combined treatment enhanced the recovery of neuromuscular function and β3-tubulin-positive axonal outgrowth, indicating an increase in the number of functioning motor axons connecting to the muscle after neurorrhaphy. Our findings suggest that the SIS membrane offers a new microenvironment for neural tissue and promotes neural regeneration based on SDC3-GDNF signaling, providing a potential therapeutic approach for PNR.

Targeting Chondroitin Sulphate Synthase 1 (Chsy1) Promotes Axon Growth Following Neurorrhaphy by Suppressing Versican Accumulation

Versican is a chondroitin sulfate proteoglycan (CSPG), which deposits in perineurium as a physical barrier and prevents the growth of axons out of the fascial boundary. Several studies have indicated that the chondroitin sulfate (CS) chains on versican have several possible functions beyond the physical barrier, including the ability to stabilize versican core protein in the extracellular matrix. As chondroitin sulfate synthase 1 (Chsy1) is a crucial enzyme for CS elongation, we hypothesized that in vivo knockdown of Chsy1 at peripheral nerve lesion site may decrease CS and versican accumulation, and result in accelerating neurite regeneration. In the present study, end-to-side neurorrhaphy (ESN) in Wistar rats was used as an in vivo model of peripheral nerve injury to evaluate nerve regeneration after surgical intervention. The distribution and expression of versican and Chsy1 in regenerating axons after ESN was studied using confocal microscopy and western blotting. Chsy1 was silenced at the nerve lesion (surgical) site using in vivo siRNA transfection. The results indicated that Chsy1 was successfully silenced in nerve tissue, and its downregulation was associated with functional recovery of compound muscle action potential. Silencing of Chsy1 also decreased the accumulation of versican core protein, suggesting that transient treating of Chsy1-siRNA may be an alternative and an effective strategy to promote injured peripheral nerve regeneration.

Corneal Biomechanical Characteristics in Osteogenesis Imperfecta With Collagen Defect

Purpose

To identify the characteristic corneal biomechanical properties of osteogenesis imperfecta (OI), and to compare the corneal biomechanical properties between OI and keratoconus.

Methods

We included 46 eyes of 23 patients with OI, 188 eyes of 99 keratoconus patients, and 174 eyes of 92 normal controls to compare corneal biomechanical parameters between OI corneas, keratoconus, and normal controls by using Corneal Visualization Scheimpflug Technology (Corvis ST).

Results

Patients with OI had significantly higher Corvis biomechanical index (CBI) (P < 0.001), higher tomographic and biomechanical index (TBI) (P = 0.040), lower Corvis Biomechanical Factor (CBiF) (P = 0.034), and lower stiffness parameter at first applanation (SP-A1) (P < 0.001) compared with normal controls. In contrast, OI group showed lower CBI (P < 0.001), lower TBI (P < 0.001), higher CBiF (P < 0.001), and higher SP-A1 (P = 0.020) than keratoconus group. Notably, the stress-strain index (SSI) was not significantly different between the OI and normal controls (P = 1.000), whereas keratoconus showed the lowest SSI compared with OI group (P = 0.025) and normal controls (P < 0.001).

Conclusions

Although the corneal structures of OI patients are less stable and easier to deform as compared to those of the control group, there is no significant difference in material stiffness observed between the OI and normal controls. In contrast, the corneas of keratoconus showed not only lower structural stability and higher deformability but also lower material stiffness compared with those of OI cornea and normal controls.

Translational Relevance

The biomechanical alterations are different between OI corneas and keratoconus.

Impact of Long Noncoding RNA LINC00673 Genetic Variants on Susceptibility to Diabetic Retinopathy

Long noncoding RNAs (lncRNAs) have been proven to play critical roles in diabetic retinopathy (DR). This study investigated whether the single nucleotide polymorphism (SNP) of long intergenic noncoding RNA 00673 (LINC00673) affects the clinical characteristics of diabetic retinopathy (DR). A total of three loci of LINC00673 SNPs (rs6501551, rs9914618, and rs11655237) were genotyped using TaqMan allelic discrimination in 276 and 454 individuals with and without DR, respectively. Our results revealed that LINC00673 SNP rs11655237 CT genotype (AOR: 1.592, 95% CI: 1.059–2.395, p = 0.026), CT + TT genotype (AOR: 1.255, 95% CI: 1.029–1.531, p = 0.025), and allele T (AOR: 1.185, 95% CI: 1.004–1.397, p = 0.044) yielded higher ratios in the non-proliferative diabetic retinopathy (NPDR) subgroup than in the non-DR group. Furthermore, the interval of diabetes mellitus (DM) was significantly shorter in the LINC00673 SNP rs11655237 CT + TT variant than that in the LINC00673 SNP rs11655237 wild type (10.44 ± 7.10 vs. 12.98 ± 8.34, p = 0.009). In conclusion, the LINC00673 SNP rs11655237 T allele is associated with a higher probability of NPDR development. Patients with the LINC00673 SNP rs11655237 CT + TT variant exhibited a short DM interval.

Association of Long Non-Coding RNA Growth Arrest-Specific 5 Genetic Variants with Diabetic Retinopathy

The aim of this work was to appraise the potential associations of single nucleotide polymorphisms (SNPs) of long non-coding RNA growth arrest-specific 5 (GAS5) with diabetic retinopathy (DR) in a diabetes mellitus (DM) population. Two loci of the GAS5 SNPs (rs55829688 and rs145204276) were genotyped via TaqMan allelic discrimination in 449 non-DR patients and 273 DR subjects. The SNP rs145204276 Del/Del showed a significantly higher distribution in the DR group compared to the non-DR group (AOR: 2.487, 95% CI: 1.424–4.344, p = 0.001). During subgroup analyses, the non-proliferative diabetic retinopathy (NPDR) subgroup demonstrated a significantly higher ratio of the SNP rs145204276 Del/Del (AOR: 2.917, 95% CI: 1.574–5.406, p = 0.001) and Ins/Del + Del/Del (AOR: 1.242, 95% CI: 1.016–1.519, p = 0.034) compared to the non-DR population, while the proliferative diabetic retinopathy (PDR) subgroup did not reveal significant differences in either SNP rs145204276 or rs55829688 distributions compared to the non-DR group. Furthermore, patients with a GAS5 SNP rs145204276 Del/Del showed a significantly shorter DM duration than the wild type (Ins/Ins) (p = 0.021). In conclusion, our findings demonstrate that the GAS5 SNP rs145204276 Del/Del variant is associated with an increased susceptibility to DR in DM patients, particularly in those patients with NPDR.

The incidence of uveitis after systemic lymphoma in Taiwan: An 18-year nationwide population-based cohort study

Although uveitis can be an intraocular presentation of systemic lymphoma, it may be associated with direct lymphomatous infiltration and immune-mediated alterations. There have been no published studies describing the incidence of uveitis after systemic lymphoma. We conducted a nationwide cohort study to investigate the incidence of uveitis after systemic lymphoma diagnosis in Taiwan. Data were collected from the Taiwan National Health Insurance system and included patients newly diagnosed with systemic lymphoma between 2000 and 2017. We observed the risk of uveitis among study population since the index date until December 2017. The 1:8 of systemic lymphoma patient and paired comparison was identified by time distribution matching and individual paired with sex and age. Subsequent propensity score matching (PSM) was used to select the 1:1 of systemic lymphoma patient and paired comparison by greedy algorism with caliper of 0.05. The multiple Cox proportional hazard regression model was used to compare the developmental risk of uveitis (time-to-uveitis) between the systemic lymphoma and non-systemic lymphoma, while controlling for selected covariates. After time distribution matching, we selected 6846 patients with systemic lymphoma, and 54,768 comparisons. Among patients with systemic lymphoma groups, there were more men than women (52.94% vs 47.06%) and the mean age was 53.32 ± 21.22 years old. Systemic lymphoma incidence rates (per 10,000 person-months) of uveitis were 1.94 (95% confidence interval [CI], 1.60-2.35) in the systemic lymphoma cohort and 1.52 (95% CI, 1.42-1.63) in the non-systemic lymphoma cohort. Compared with the non-systemic lymphoma cohort, adjusted hazard ratio (aHR) of developing uveitis were 1.24 (95% CI, 1.00-1.52) in people with systemic lymphoma. But not significant in after PSM, aHR of developing uveitis were 1.17 (95% CI, 0.90-1.53). This 18-year nationwide population-based cohort study in Taiwan, showed that the risk of uveitis in patients' systemic lymphoma was not significantly higher than non-systemic lymphoma after PSM. In elderly and rheumatic patients with intraocular inflammation, it is important to first exclude uveitis masquerade syndrome, which could be a harbinger of intraocular involvement from systemic lymphoma. Further large-scale prospective clinical studies to investigate whether systemic lymphoma influences the incidence of uveitis are warranted.

Association Between Subconjunctival Hemorrhage and Acute Coronary Syndrome: A 14-Year Nationwide Population-Based Cohort Study

Purpose: Subconjunctival hemorrhage (SCH) is usually a benign ocular disorder that causes painless, redness under the conjunctiva. However, since SCH and acute coronary syndrome (ACS) share many vascular risk factors, studies have suggested that these two disorders may be significantly associated with each other, and evaluate the concomitance of ACS in patients with SCH.

Methods: This population-based cohort study, enrolled 35,260 Taiwanese patients, and used the Taiwan National Health Insurance Research Database to identify patients with ACS and SCH. Outcomes were compared between the with and without SCH groups. The study population was followed until the date of ACS onset, the date of withdrawal, death, or December 31st 2013, whichever came first.

Results: Of the 85,925 patients identified with SCH between 1996 and 2013, 68,295 were excluded based on the study's exclusion criteria, and a total of 17,630 patients with SCH who were diagnosed by ophthalmologists between 2000 and 2012 were eligible for analysis. After 1:1 propensity score matching for 5-year age groups, gender, and the index year, the results showed that SCH was more common in the 40–59 age group (53.82%) and females (58.66%). As for the ACS-related risk factors, patients with diabetes mellitus (aHR = 1.58, 95% CI = [1.38, 1.81]), hypertension (aHR = 1.71, 95% CI = [1.49, 1.96]) and patients taking aspirin (aHR = 1.67, 95% CI = [1.47, 1.90]) had a notably higher risk of ACS. However, it was found that there were no significant differences in the occurrence of ACS between the non-SCH and SCH patients.

Conclusion: This results of this study regarding the risk factors and epidemiology of SCH and ACS were in keeping with previously reported findings. However, the results revealed no significant association between SCH and ACS.

Deep Learning for Automated Diabetic Retinopathy Screening Fused With Heterogeneous Data From EHRs Can Lead to Earlier Referral Decisions

Purpose

Fundus images are typically used as the sole training input for automated diabetic retinopathy (DR) classification. In this study, we considered several well-known DR risk factors and attempted to improve the accuracy of DR screening.

Metphods

Fusing nonimage data (e.g., age, gender, smoking status, International Classification of Disease code, and laboratory tests) with data from fundus images can enable an end-to-end deep learning architecture for DR screening. We propose a neural network that simultaneously trains heterogeneous data and increases the performance of DR classification in terms of sensitivity and specificity. In the current retrospective study, 13,410 fundus images and their corresponding nonimage data were collected from the Chung Shan Medical University Hospital in Taiwan. The images were classified as either nonreferable or referable for DR by a panel of ophthalmologists. Cross-validation was used for the training models and to evaluate the classification performance.

Results

The proposed fusion model achieved 97.96% area under the curve with 96.84% sensitivity and 89.44% specificity for determining referable DR from multimodal data, and significantly outperformed the models that used image or nonimage information separately.

Conclusions

The fusion model with heterogeneous data has the potential to improve referable DR screening performance for earlier referral decisions.

Translational Relevance

Artificial intelligence fused with heterogeneous data from electronic health records could provide earlier referral decisions from DR screening.

Changes in the Systemic Expression of Sirtuin-1 and Oxidative Stress after Intravitreal Anti-Vascular Endothelial Growth Factor in Patients with Retinal Vein Occlusion

OBJECTIVES

Retinal vein occlusions (RVO) are associated with systemic risk factors. However, the ocular occlusive events might also influence a patient's systemic condition. This study tried to investigate serum biomarkers associated with oxidative stress, before and after intravitreal anti-vascular endothelial growth factor (aVEGF) therapy in patients with RVOs.

METHODS

Newly-onset RVO patients were categorized into two groups: comorbid with macular edema requiring aVEGF therapy (treatment group) and no edema (observation group). Age and sex-matched patients (who received cataract surgery) were included as the control group. Intravitreal ranibizumab with a pro-re-nata regimen were administered. Serum samples were collected prior to treatment, at 6 and 12 months after therapy/observation and were collected once before controls who received cataract surgery. mRNA expression of sirtuin-1, its downstream genes, anti-oxidative biomarkers, and proinflammatory cytokines were measured.

RESULTS

There were 32, 26, and 34 patients enrolled in the treatment, observation, and control groups, respectively. The expressions of sirtuin-1 and its downstream genes were significantly lower in patients with RVO compared with the control group. Sirtuin-1 gene expression increased after 1 year of aVEGF therapy in the treatment group but remained unchanged in the observation group. Biomarkers of oxidative stress and proinflammatory cytokines were reduced after 1 year of aVEGF therapy. These biomarkers remained with no changes in the observation group.

CONCLUSIONS

Our study showed that the systemic oxidative stress increased in RVO patients. The aVEGF therapy could alter the gene expression of anti-oxidative proteins and reduce systemic oxidative stress in these patients.

Home Sample Self-Collection for COVID-19 Patients

Real‐time reverse transcription‐polymerase chain reaction (qRT‐PCR) using specimens collected from nasopharyngeal and/or oropharyngeal swabs is the standard screening approach for coronavirus disease 2019 (COVID‐19). While PCR is rapid and highly accurate, it requires costly laboratory equipment and healthcare professionals that limit its use for large‐scale screening of mild or asymptomatic patients. Self‐collection kits for use in the home could remedy this and have consequently received great attention. In April, 2020, a self‐collection kit from LapCorp was the first such kit to be approved by the FDA. In the following month, May 2020, another kit developed by Everlywell received FDA approval, and more kits are evidently on their way to the market in the United Kingdom and elsewhere. Because these home‐based, self‐collection kits are easy to use and may be more acceptable for patients, they provide a superior screening option for mild or asymptomatic patients under self‐quarantine. These kits conserve personal protective equipment and healthcare manpower already in short supply. The primary issues affecting the efficacy of this approach are the potential for inappropriate sampling and insufficient clinical examination. A detailed review of the commercially available kits currently available is provided and their prospective impact is noted during the current pandemic.

The Global Leadership Mentoring Community: building capacity across seven global regions

AIM

The purpose of this paper is to report on the evaluation of the online Global Leadership Mentoring Community, a programme designed to build relationships across seven global regions and promote leadership development for emerging nurse leaders.

BACKGROUND

There is a pressing need and opportunity for sustainable global leadership mentoring programmes. This programme of Sigma Theta Tau International (Sigma) brought mentors and mentees together from across the world to build leadership capacity, understand global leadership issues and build networks. Community coordinators purposively selected mentors from each of Sigma's seven Global Regions, and mentees were chosen through a process of snowball sampling. Mentors and mentees met monthly with quarterly group calls.

METHODS

The study followed a programme evaluation, outcomes-focused approach. All eleven pairs of mentors-mentees were invited to complete online surveys at the outset and end of programme capturing both quantitative and qualitative data. Quantitative data were analysed using descriptive statistics and for qualitative data, a thematic analysis.

FINDINGS

Quantitative data confirmed that all 22 participants gained from the experience. From qualitative analysis, themes emerged illustrating the scope of achievements: 1. facilitation of successful outcomes for both mentors and mentees, 2. challenges of global mentoring and 3. strategies for successful global mentoring.

DISCUSSION/CONCLUSION

Participants reported that creating global leadership is a longitudinal process that needs sustained attention to effect change. This evaluation identified many strengths of the programme and recommended its continuation to help further development of global leaders, particularly through focusing more purposefully on policy issues.

IMPLICATIONS FOR NURSING POLICY

Empowerment of nurses globally through a Global Leadership Mentoring Community can improve leadership at all levels, thus emboldening their voices to influence nursing and health policy and ultimately improve patient care.

Impact of the Severities of Glaucoma on the Incidence of Subsequent Dementia: A Population-Based Cohort Study

The aim of the present study was to survey the relationship between the severity of glaucoma and subsequent dementia using the National Health Insurance Research Database (NHIRD) in Taiwan. Subjects with glaucoma were selected into the study group after an exclusion process, and each subject in the study group was propensity score-matched to another non-glaucoma patient that constituted the control group. The Cox proportional hazard regression that considered multiple potential risk factors of dementia was used to yield the adjusted hazard ratios (aHR) of dementia in different severities of glaucoma. There were 1185 (5.63 percent) subjects in the study group and 1119 (5.32 percent) patients in the control group that developed dementia. After adjusting for multiple confounders, there were no differences in the rate of any dementia (aHR: 0.961, 95% CI: 0.886–1.043, p = 0.3443), vascular dementia (aHR: 0.928, 95% CI: 0.846–1.018, p = 0.1154), Alzheimer’s disease (aHR: 1.018, 95% CI: 0.761–1.362, p = 0.9025) or Parkinson’s disease (aHR: 1.021, 95% CI: 0.886–1.176, p = 0.7744) between the study and the control groups. Regarding the disease severity of glaucoma, no difference was found in any type of dementia whether the glaucoma patients received less than two medical treatments, received more than two medical treatments, received drainage surgeries or received destructive surgeries. In conclusion, the different severities of glaucoma do not alter the incidence of subsequent dementia.

A Murine Model of Acute Allergic Conjunctivitis Induced by Continuous Exposure to Particulate Matter 2.5

Purpose

Several pieces of epidemiologic evidence have indicated PM2.5 (particulate matter with a diameter of 2.5 μm or less) as a causing factor of allergic conjunctivitis, but without experimental elucidation of mechanism. In the present study, PM2.5 in solution was directly applied to the mouse ocular surface to elucidate whether PM2.5 might cause allergic conjunctivitis, and its underlying mechanisms were analyzed.

Methods

ICR mice were challenged for 18 consecutive days with eye drops containing PM2.5 at 3.2, 6.4, and 12.8 mg/mL in 0.9% NaCl saline, along with the controls prepared in parallel without PM2.5 and another control group treated with both PM2.5 at 12.8 mg/mL and artificial tears. On day 19, the whole eyes and meibomian glands were harvested for histopathological analyses and assessment of clinical scoring, tear volume, tear breakup time, and tear ferning. Furthermore, goblet cells by periodic acid Schiff stain and infiltrated eosinophils by Giemsa stain were quantified and compared among study groups.

Results

Clinical scoring showed more eyelid edema, tearing, and scratching behaviors, with longer tear breakup time under the influence of increased PM2.5 concentrations. Tear ferning assay showed less tear crystal formation and decreased crystal branches after exposure to PM2.5. In addition, higher goblet cell density in the upper palpebral conjunctiva and extensive eosinophil infiltration in the entire conjunctiva and in the meibomian glands were induced by PM2.5.

Conclusions

These results demonstrate that PM2.5 can induce symptoms similar to clinical allergic conjunctivitis and that the murine acute allergic conjunctivitis model can be induced by direct exposure to PM2.5.

2420Effects of a selective small-molecule formyl peptide receptor 2 agonist on post myocardial inflammation and left ventricular structure-function relationships

Background/Introduction

Dysregulated inflammation following myocardial infarction (MI) can lead to maladaptive infarct healing, myocardial damage and heart failure. Formyl peptide receptor 2 (FPR2) plays an important role in the ligand-dependent regulation of inflammation resolution. Stimulation of resolution via FPR2 activation is hypothesized to preserve left ventricular (LV) structure-function relationships thereby preventing pathological cardiac remodeling, and heart failure.

Purpose

We evaluated a selective 4-phenylpyrrolidinone FPR2 agonist in rodent MI models by assessing the impact on LV and infarct scar remodeling and cardiac function.

Methods

The FPR2 agonist was evaluated in phagocytosis, chemotaxis and cytokine response assays. In vivo, following permanent occlusion of the left anterior descending (LAD) artery, C57BL/6 mice or Sprague-Dawley rats were treated with the FPR2 agonist or vehicle; PO gavage, QD. Treatment began 24 hours after occlusion (0.3 and 3 mg/kg) and continued for three days to assess early inflammation or four weeks to evaluate LV and infarct structure and function. Rats subjected to permanent MI were treated 48 hours after occlusion (0.01, 0.1. 1, 10 mg/kg) for six weeks to assess structure-function relationships. A parallel study in rats evaluated compound treatment (0.01, 0.1. 1, 10 mg/kg) following 60 minutes occlusion and reperfusion of the LAD artery.

Results

The FPR2 agonist enhanced cellular phagocytosis and chemotaxis, and stimulated IL-10 and MCP-1 gene expression in isolated human whole blood. In mice, FPR2 agonist treatment improved survival post MI, reduced LV chamber area and infarct size (26% and 55% vs. vehicle, respectively, P<0.05) and preserved infarct wall thickness (59% vs. vehicle, P<0.05). Treatment increased macrophage arginase 1 levels three days post-MI in the infarct border zone and CD206 levels in the whole heart, indicating a shift towards a pro-resolution phenotype. In rats, FPR2 agonist treatment preserved infarct wall thickness (maximal at 10 mg/kg, 96% vs. vehicle, P<0.05) and increased LV ejection fraction at all doses (+9% vs. vehicle, P<0.05). Following occlusion and reperfusion of the LAD artery, treatment preserved viable myocardium across the infarct wall at multiple doses (25–41%, P<0.05) resulting in increased ejection fraction (14% and 19% vs vehicle at 0.01 and 1 mg/kg, respectively, P<0.05).

Conclusion(s)

Improvements in cardiac structure-function versus vehicle treated animals support the concept that agonism of FPR2 improves post-MI wound healing, limiting adverse post-MI LV remodeling, thereby preserving cardiac function. These preclinical results suggest targeting FPR2 may present an innovative approach towards development of effective drug therapies to prevent heart failure post-MI.

Acknowledgement/Funding

Bristol-Myers Squibb Company

Risk of developing open-angle glaucoma in patients with carotid artery stenosis: A nationwide cohort study

Whether carotid artery stenosis (CAS) is an independent risk factor for open-angle glaucoma remains unclear. In this study, we investigated the association between CAS and the development of open-angle glaucoma in the Taiwanese population-based cohort derived from a longitudinal database containing claims data from the Taiwan National Health Insurance (NHI) program; this study enrolled 2093 patients with CAS and 8372 patients without CAS matched by age and sex from 1999 to 2010. Diagnoses of open-angle glaucoma (OAG) were identified during a follow-up period lasting through December 31, 2013. A Cox proportional hazards model was applied to evaluate the hazard ratio (HR) for OAG in the CAS cohort compared with the matched cohort. We found that the HR for open-angle glaucoma in the CAS cohort compared with the matched cohort. The adjusted HR for OAG in the CAS cohort was 1.50 (95% confidence interval, 1.11-2.02, P = .008). The Kaplan-Meier analysis revealed that the CAS cohort had a higher cumulative incidence of OAG than did the matched cohort during the follow-up period (log-rank test, P < .001). We concluded that CAS is a significantly independent risk factor for the development of OAG. Our finding is clinically important for the aging population, which has an increasing prevalence of CAS.

Association between antipsychotic drug use and cataracts in patients with bipolar disorder: A population-based, nested case-control study

BACKGROUND

No previous study has focused on the association between use of antipsychotic drugs and the development of cataracts in patients with bipolar disorder (BD); hence, we aimed to examine this association in the present study.

METHODS

We conducted a retrospective nested case-control study using data from the National Health Insurance Database of Taiwan between 2000 and 2011. A total of 3292 BD patients, 1684 with cataracts and 1608 controls matched for age, sex, and index date, were included. Antipsychotic drug exposure was categorized by type of drug and duration of use. A conditional logistic regression analysis was used to analyze the association.

RESULTS

Among BD patients, we found significantly reduced odds ratio (OR) of cataract development among past (adjusted OR (AOR), 0.74; 95% confidence interval (CI), 0.62-0.89; p=0.001) and continuous users (AOR, 0.71; 95% CI, 0.59-0.85; p<0.001) of atypical antipsychotics. No association was found between the odds of cataract development and typical antipsychotics. Besides, concomitant use of antidepressants (AOR, 1.23; 95% CI, 1.06-1.43; p=0.007) and mood stabilizers (AOR, 1.23; 95% CI, 1.06-1.42; p=0.007) were associated with increased odds of cataract development.

LIMITATIONS

Some important contributors to cataract development such as family history of cataract, smoking and alcohol exposure could not be measured from the claims data and this may confound the results.

CONCLUSIONS

Reduced odds of cataract were found in patients with BD taking atypical antipsychotics. However, given that BD patients often have risk factors for developing cataract, regular ocular evaluations are recommended for those treated with antipsychotics drugs.

Paper-based CRP Monitoring Devices

Here, we discuss the development of a paper-based diagnostic device that is inexpensive, portable, easy-to-use, robust, and capable of running simultaneous tests to monitor a relevant inflammatory protein for clinical diagnoses i.e. C-reactive protein (CRP). In this study, we first attempted to make a paper-based diagnostic device via the wax printing method, a process that was used in previous studies. This device has two distinct advantages: 1) reduced manufacturing and assay costs and operation duration via using wax printing method to define hydrophobic boundaries (for fluidic devices or general POC devices); and, 2) the hydrophilicity of filter paper, which is used to purify and chromatographically correct interference caused by whole blood components with a tiny amount of blood sample (only 5 μL). Diagnosis was based on serum stain length retained inside the paper channels of our device. This is a balanced function between surface tension and chromatographic force following immune reactions (CRP assays) with a paper-embedded biomarker.

Fabricating Cotton Analytical Devices

A robust, low-cost analytical device should be user-friendly, rapid, and affordable. Such devices should also be able to operate with scarce samples and provide information for follow-up treatment. Here, we demonstrate the development of a cotton-based urinalysis (i.e., nitrite, total protein, and urobilinogen assays) analytical device that employs a lateral flow-based format, and is inexpensive, easily fabricated, rapid, and can be used to conduct multiple tests without cross-contamination worries. Cotton is composed of cellulose fibers with natural absorptive properties that can be leveraged for flow-based analysis. The simple but elegant fabrication process of our cotton-based analytical device is described in this study. The arrangement of the cotton structure and test pad takes advantage of the hydrophobicity and absorptive strength of each material. Because of these physical characteristics, colorimetric results can persistently adhere to the test pad. This device enables physicians to receive clinical information in a timely manner and shows great potential as a tool for early intervention.

Paper-based ELISA to rapidly detect Escherichia coli

Escherichia coli is a generic indicator of fecal contamination, and certain serotypes cause food- and water-borne illness such as O157:H7. In the clinic, detection of bacteriuria, which is often due to E. coli, is critical before certain surgical procedures or in cases of nosocomial infection to prevent further adverse events such as postoperative infection or sepsis. In low- and middle-income countries, where insufficient equipment and facilities preclude modern methods of detection, a simple, low-cost diagnostic device to detect E. coli in water and in the clinic will have significant impact. We have developed a simple paper-based colorimetric platform to detect E. coli contamination in 5h. On this platform, the mean color intensity for samples with 10(5)cells/mL is 0.118±0.002 (n=4), and 0.0145±0.003 (P<0.01⁎⁎) for uncontaminated samples. This technique is less time-consuming, easier to perform, and less expensive than conventional methods. Thus, paper-based ELISA is an innovative point-of-care diagnostic tool to rapidly detect E. coli, and possibly other pathogens when customized as appropriate, especially in areas that lack advanced clinical equipment.

Monitoring VEGF levels with low-volume sampling in major vision-threatening diseases: age-related macular degeneration and diabetic retinopathy

The purpose of this article is to demonstrate the capacity of paper-based ELISA (P-ELISA) to monitor VEGF in patients requiring treatment for vision-threatening diseases. The most commonly encountered vision-threatening diseases are age-related macular degeneration (AMD) and diabetic retinopathy (DR), both of which may require short-term or life-long anti-VEGF injection treatment therapy. Accurate measurement of VEGF concentration in aqueous humor can provide significant and timely information to diagnose the disease state. Adequate and precise therapy may consequently be provided. At odds with conventional diagnostic approaches is the fact that a maximum of only 200 microliters of aqueous humor can be safely removed from the eye for testing. Fortunately, new diagnostic platforms, such as P-ELISA, require only minute volumes, i.e., approximately 2 microliters per test "well" and approximately 40 microliters total to quantify VEGF levels, and the testing process takes less than an hour. Thus, point-of-care (POC) diagnostics, such as P-ELISA, should be examined and improved upon as needed in order to develop an efficient tool for outpatient clinics and others to obtain semi-quantitative results that might facilitate accurate dosing of anti-VEGF treatment and delay or prevent the progression of AMD and DR.

Evaluating organophosphate poisoning in human serum with paper

This manuscript describes the development and clinical testing of a paper-based, metabolic assay designed for rapid, semi-quantitative measurement of organophosphate poisoning. Paper-based platforms, including point-of-care devices and 96-well plates, provided semi-quantitative information regarding the concentration of AchE (a biomarker for organophosphate poisoning). The paper-based 96-well-plate developed and implemented in this study was used to measure the level of organophosphate poisoning in three different clinical patients. Results were comparable to those obtained using conventional hospital methods currently considered the "gold standard". This diagnostic device offers several advantages over conventional methods, including short operating time (twice as fast as conventional methods), procedure simplicity, and reduced fabrication cost. With further commercialization efforts, the methods described in this manuscript could be applied to a wide range of potential diagnostic applications in the field.

Paper-based devices for isolation and characterization of extracellular vesicles

Extracellular vesicles (EVs), membranous particles released from various types of cells, hold a great potential for clinical applications. They contain nucleic acid and protein cargo and are increasingly recognized as a means of intercellular communication utilized by both eukaryote and prokaryote cells. However, due to their small size, current protocols for isolation of EVs are often time consuming, cumbersome, and require large sample volumes and expensive equipment, such as an ultracentrifuge. To address these limitations, we developed a paper-based immunoaffinity platform for separating subgroups of EVs that is easy, efficient, and requires sample volumes as low as 10 μl. Biological samples can be pipetted directly onto paper test zones that have been chemically modified with capture molecules that have high affinity to specific EV surface markers. We validate the assay by using scanning electron microscopy (SEM), paper-based enzyme-linked immunosorbent assays (P-ELISA), and transcriptome analysis. These paper-based devices will enable the study of EVs in the clinic and the research setting to help advance our understanding of EV functions in health and disease.

Kosmotrope-like hydration behavior of polyethylene glycol from microcalorimetry and binding isotherm measurements

Polyethylene glycol (PEG) at various molecular weights (MWs) has been regarded as a wonder molecule in biomedical applications. For instance, PEG serves as a unique moiety for pegylation of "biobetter" drug development, PEG provides controlled-release and preserved activity of biologics, and PEG modified surface works as an antibiofouling surface. The primary characteristics of PEG molecules used in relevant applications have been attributed mainly to the hydration behavior in aqueous solutions. However, the effects on the solvation of solutes in solution caused by presenting PEG molecules as a cosolvent, as well as the thermodynamics aspect of the hydration behavior of PEG in solution, have not been well documented. The solvation behavior of solutes, such as protein, with PEG as a cosolvent, indicates the success of PEG applications, such as biofouling and controlled release. In this investigation, we examined the effects of a buffer solution containing PEG molecules on the solution behavior of solute and the interactions between solid surfaces with solutes. We adapted the study by selecting a lysozyme as a solute in a buffer solution with either ammonium sulfate (kosmotrope) or sodium chloride (chaotrope) and anionic resin (SP-Sepharose) as solid surfaces. The experiments primarily involved binding equilibrium measurements and thermodynamics analysis. The results revealed that, in both saline buffers, adding PEG increases the binding affinity between the lysozyme and the resin, similar to kosmotropic salt in the examined salt concentrations. The thermodynamics analyses involving microcalorimetric measurements show that the bindings are mainly driven by enthalpy, indicating that electrostatic interaction was the primary binding force under these experimental conditions. The variations of the enthalpy and entropy of the binding thermodynamics when adding PEG to different salt types in the buffer solution showed opposite behavior, and the results support the concept of kosmotrope-like behavior of PEG. The equilibrium and thermodynamics data demonstrate that PEG has a kosmotrope-like hydration behavior, and the extent of kosmotrope-like behavior depends on the molecular weight of PEG with the outcomes of various molecular weights of PEG being added to the binding solution. The results of this study provide essential knowledge for PEG as an additive (or cosolvent) in various research applications.

Alpha5 and alpha2 integrin gene transfers mimic the PDGF-B-induced transformed phenotype of fibroblasts in human skin

Platelet-derived growth factor (PDGF)-B is a proto-oncogene capable of transforming fibroblasts. Using adenoviral vectors, we tested whether endogenous PDGF-B expression in human skin xenotransplants leads to changes in the expression of alpha5 and alpha2 integrin subunits and whether integrin overexpression leads to PDGF-related changes in the skin. In vitro, transduction of fibroblasts with PDGF-B or the integrin alpha5 subunit stimulated multilayered growth and spindle-type morphology, both markers of mesenchymal cell transformation. In vivo, PDGF-B transduction of the human dermis was associated with up-regulation of collagen and fibronectin synthesis, increases in alpha5 and alpha2 integrin subunit expression, vessel formation, and proliferation of fibroblasts, keratinocytes, and pericytes. A similar stromal response was induced when alpha5 and alpha2 integrin subunits were overexpressed in the human dermis, suggesting that integrins play a major role in the induction of a transformed phenotype of fibroblasts by PDGF-B.

A large family of eukaryotic-like protein Ser/Thr kinases of Myxococcus xanthus, a developmental bacterium

Myxococcus xanthus is a gram-negative bacterium that forms multicellular fruiting bodies upon starvation. Here, we demonstrate that it contains at least 13 eukaryotic-like protein Ser/Thr kinases (Pkn1 to Pkn13) individually having unique features. All contain the kinase domain of approximately 280 residues near the N-terminal end, which share highly conserved features in eukaryotic Ser/Thr kinases. The kinase domain is followed by a putative regulatory domain consisting of 185 to 692 residues. These regulatory domains share no significant sequence similarities. The C-terminal regions of 11 kinases contain at least 1 transmembrane domain, suggesting that they function as transmembrane sensor kinases. From the recent genomic analysis, protein Ser/Thr kinases were found in various pathogenic bacteria and coexist with protein His kinases. Phylogenetic analysis of these Ser/Thr kinases reveals that all bacterial Ser/Thr kinases were evolved from a common ancestral kinase together with eukaryotic Tyr and Ser/Thr kinases. Coexistence of both Ser/Thr and His kinases in some organisms may be significant in terms of functional differences between the two kinases. We argue that both kinases are essential for some bacteria to adapt optimally to severe environmental changes.

E-cadherin expression in melanoma cells restores keratinocyte-mediated growth control and down-regulates expression of invasion-related adhesion receptors

In human epidermis, functional symbiosis requires homeostatic balance between keratinocytes and melanocytes. Compelling evidence from co-culture studies demonstrated a sophisticated, multileveled regulation of normal melanocytic phenotype orchestrated by undifferentiated, basal-type keratinocytes. Keratinocytes control cell growth and dendricity, as well as expression of melanoma-associated cell surface molecules of normal melanocytes. In contrast, melanoma cells are refractory to the keratinocyte-mediated regulation. The loss of regulatory dominance by keratinocytes occurs in concert with down-regulation of E-cadherin expression in melanoma cells. To investigate the potential role of E-cadherin in melanoma-keratinocyte interaction, we transduced E-cadherin-negative melanoma cells with full-length E-cadherin cDNA using an adenoviral vector. Our results show that functional E-cadherin expression in melanoma cells leads to cell adhesion to keratinocytes rendering them susceptible for keratinocyte-mediated control. In a skin reconstruction model, ectopic E-cadherin expression inhibits invasion of melanoma cells into dermis by down-regulating invasion-related adhesion receptors, MelCAM/MUC18 and beta3 integrin subunit, and by induction of apoptosis. Thus, disruption of the E-cadherin-mediated, normal regulatory control from keratinocytes may represent one of the mechanisms accounting for melanocyte transformation.

Human xenografts, human skin and skin reconstructs for studies in melanoma development and progression

Melanoma develops from a series of architectural and phenotypically distinct stages and becomes progressively aggressive. Considerable progress has been made in understanding the biological, pathological, and immunological aspects of human melanoma. Genetic and cytogenetic studies have revealed broad chromosomal abnormalities and wide mutational spectra. Precise biological and molecular determinants responsible for melanoma progression are not yet known. This is in part due to lack of experimental models that mimic human melanomas. Experimental models in melanoma should not only identify cause and origin of malignancy, but also should represent the ordered progression steps that culminate in metastasis to distant organs. Currently, there are several mouse and other vertebrate melanoma models under investigation; several of them promise to shed light on mechanisms of melanomagenesis. However, many of them suffer from lack of context to human skin architecture and hence, are of basic interest. The lack of appropriate models impeded the efforts to understand origin, etiology, progression and ultimately therapeutic benefits to humans. Development of human skin-mouse chimeric models has appeal because it mimics human diseases. In addition, human artificial skin constructs in vitro promises to be a versatile and efficient model to study not only origin and mechanisms of melanoma, but also progression. This review will focus on the recent progress in establishing tumor models in melanoma in general and their relevance to human melanoma as molecular determinants of tumor progression.

Determination of cyclamate in low-calorie foods by high-performance liquid chromatography with indirect visible photometry

A rapid and simple method using reversed-phase high-performance liquid chromatography combined with indirect visible photometry at 433 nm was developed to determine cyclamate in some food samples. Cyclamate was not detected in these chosen samples as its use is banned in Hong Kong. Cyclamate can easily be detected in spiked samples using a mobile phase consisting of 30 mumol dm-3 Methyl Red and 0.02 mol dm-3 phosphate buffer (pH 7.0)-methanol in a volume ratio of 3:2. The column temperature was set at 23 degrees C. The detection limit was 0.14 mmol dm-3 and the relative standard deviation of the peak area response was 0.58% for a solution containing 5.0 mmol dm-3 of cyclamate (n = 8). This method was successfully applied to the analysis of eight spiked food samples and the cyclamate recoveries for these samples ranged from 93 to 99%.

Human melanoma progression in skin reconstructs : biological significance of bFGF

Human skin reconstructs are three-dimensional in vitro models consisting of epidermal keratinocytes plated onto fibroblast-contracted collagen gels. Cells in skin reconstructs more closely recapitulate the in situ phenotype than do cells in monolayer culture. Normal melanocytes in skin reconstructs remained singly distributed at the basement membrane which separated the epidermis from the dermis. Cell lines derived from biologically early primary melanomas of the radial growth phase proliferated in the epidermis and the basement membrane was left intact. Growth and migration of the radial growth phase melanoma cells in the dermal reconstruct and tumorigenicity in vivo were only observed when cells were transduced with the basic fibroblast growth factor gene, a major autocrine growth stimulator for melanomas. Primary melanoma cell lines representing the more advanced stage vertical growth phase invaded the dermis in reconstructs and only an irregular basement membrane was formed. Metastatic melanoma cells rapidly proliferated and aggressively invaded deep into the dermis, with each cell line showing typical invasion and growth characteristics. Our results demonstrate that the growth patterns of melanoma cells in skin reconstructs closely correspond to those in situ and that basic fibroblast growth factor is critical for progression.

Basic fibroblast growth factor induces a transformed phenotype in normal human melanocytes

Basic fibroblast growth factor (bFGF or FGF-2) is produced by nearly all melanomas in vitro and in vivo but not by normal melanocytes, which require exogenous bFGF for growth. In this study, we transduced normal human melanocytes to overexpress two forms of bFGF: (bFGF-Long and bFGF-Short) using replication-deficient adenovirus 5 vectors. bFGF-Long induced the 17.8, 22.5, 23.1 and 24.2 kDa forms of bFGF, whereas bFGF-Short induced only the 17.8 kDa mature form. Growth of cultured melanocytes transduced with either vector was similar to that of nevus and melanoma cells and was independent of exogenous bFGF and of insulin/insulin-like growth factor 1, and cyclic AMP enhancers, requiring only phorbol ester as an exogenous mitogen. Like primary melanoma cells, transduced normal melanocytes grew anchorage independently in soft agar. When injected into the dermis of human skin grafted to mice, bFGF-transduced melanocytes proliferated for at least 20 days, whereas cells from control cultures showed poor survival and no proliferation. These results demonstrate that bFGF upregulation is a critical component in melanoma progression.

Heparin/endothelial cell growth supplement regulates matrix gene expression and prolongs life span of vascular smooth muscle cells through modulation of interleukin-1

Vascular smooth muscle cells produce and respond to interleukin-1, a cytokine which modifies inflammation-associated vascular activities including the synthesis of extracellular matrix proteins. We have established vascular smooth muscle cells culture conditions in which heparin, in the presence of endothelial cell growth supplement, promotes cell proliferation and inhibits interleukin-1 and matrix protein expression. To test whether interleukin-1 mediates growth and matrix modulation by heparin/endothelial cell growth supplement, vascular smooth muscle cells were transfected with an Epstein-Barr virus-derived expression vector designed to express interleukin-1 antisense transcripts. RNase protection and ELISA assays demonstrated a complete block of interleukin-1 transcription and protein synthesis. Northern blot analysis also showed that interleukin-1 antisense decreased the expression of matrix genes such as type I collagen, fibronectin, and decorin similar to downregulation after heparin/endothelial cell growth supplement treatment. In contrast, the expression of versican was not affected, indicating a selective suppression of matrix proteins. In addition, interleukin-1 antisense significantly prolonged the life span of vascular smooth muscle cells in culture. Our data suggest that heparin/endothelial cell growth supplement induces matrix remodeling and controls growth and senescence of vascular smooth muscle cells through down-regulation of interleukin-1.

Highly specific recognition of primer RNA structures for 2'-OH priming reaction by bacterial reverse transcriptases

A minor population of Escherichia coli contains retro-elements called retrons, which encode reverse transcriptases (RT) to synthesize peculiar satellite DNAs called multicopy single-stranded DNA (msDNA). These RTs recognize specific RNA structures in their individual primer-template RNAs to initiate cDNA synthesis from the 2'-OH group of a specific internal G residue (branching G residue). The resulting products (msDNA) consist of RNA and single-stranded DNA, sharing hardly any sequence homology. Here, we investigated how RT-Ec86 recognizes the specific RNA structure in its primer-template RNA. On the basis of structural comparison with HIV-1 RT, domain exchanges were carried out between two E. coli RTs, RT-Ec86 and RT-Ec73. RT-Ec86 (320 residues) and RT-Ec73 (316 residues) share only 71 identical residues (22%). From the analysis of 10 such constructs, the C-terminal 91-residue sequence of RT-Ec86 was found to be essential for the recognition of the unique stem-loop structure and the branching G residue in the primer-template RNA for retron-Ec86. Using the SELEX (systematic evolution of ligands by exponential enrichment) method with RT-Ec86 and primer RNAs containing random sequences, the identical stem-loop structure (including the 3-U loop) to that found in the retron-Ec86 primer-template RNA was enriched. In addition, the highly conserved 4-base sequence (UAGC), including the branching G residue, was also enriched. These results indicate that the highly diverse C-terminal region recognizes specific stem-loop structures and the branching G residue located upstream of the stem-loop structure. The present results with seemingly primitive RNA-dependent DNA polymerases provide insight into the mechanisms for specific protein RNA recognition.

Up-regulation of ephrin-A1 during melanoma progression

Ephrin-A1, formerly called B61, is a new melanoma growth factor; it is angiogenic and chemoattractant for endothelial cells. EPH-A2, or ECK (a receptor for ephrin-A1), is ectopically expressed in most melanoma cell lines; the pathology where this expression is first manifested and the possible role of the receptor in tumor progression are unknown. To determine these, we studied the expression of this ligand and receptor in biopsies of benign and malignant melanocytic lesions. EPH-A2 was not detected in normal melanocytes, benign compound nevi or advanced melanomas, though it was found in 2 of 9 biopsies of malignant melanoma in situ. Ephrin-A1 was present in occasional early lesions and in advanced primary melanomas (43%) and metastatic melanomas (67%). Expression of ephrin-A1 was induced in melanoma cells by pro-inflammatory cytokines. Our findings are consistent with 2 possible roles for ephrin-A1 in melanoma development: it may promote melanocytic cell growth or survival and induce vascularization in advanced melanomas. Both effects may be potentiated by inflammatory responses. Our data are consistent with earlier observations that an inflammatory infiltrate is associated with poor prognosis in thin primary melanomas.

Up-regulation of ephrin-A1 during melanoma progression

Ephrin-A1, formerly called B61, is a new melanoma growth factor; it is angiogenic and chemoattractant for endothelial cells. EPH-A2, or ECK (a receptor for ephrin-A1), is ectopically expressed in most melanoma cell lines; the pathology where this expression is first manifested and the possible role of the receptor in tumor progression are unknown. To determine these, we studied the expression of this ligand and receptor in biopsies of benign and malignant melanocytic lesions. EPH-A2 was not detected in normal melanocytes, benign compound nevi or advanced melanomas, though it was found in 2 of 9 biopsies of malignant melanoma in situ. Ephrin-A1 was present in occasional early lesions and in advanced primary melanomas (43%) and metastatic melanomas (67%). Expression of ephrin-A1 was induced in melanoma cells by pro-inflammatory cytokines. Our findings are consistent with 2 possible roles for ephrin-A1 in melanoma development: it may promote melanocytic cell growth or survival and induce vascularization in advanced melanomas. Both effects may be potentiated by inflammatory responses. Our data are consistent with earlier observations that an inflammatory infiltrate is associated with poor prognosis in thin primary melanomas.

Up-regulation of ephrin-A1 during melanoma progression

Ephrin-A1, formerly called B61, is a new melanoma growth factor; it is angiogenic and chemoattractant for endothelial cells. EPH-A2, or ECK (a receptor for ephrin-A1), is ectopically expressed in most melanoma cell lines; the pathology where this expression is first manifested and the possible role of the receptor in tumor progression are unknown. To determine these, we studied the expression of this ligand and receptor in biopsies of benign and malignant melanocytic lesions. EPH-A2 was not detected in normal melanocytes, benign compound nevi or advanced melanomas, though it was found in 2 of 9 biopsies of malignant melanoma in situ. Ephrin-A1 was present in occasional early lesions and in advanced primary melanomas (43%) and metastatic melanomas (67%). Expression of ephrin-A1 was induced in melanoma cells by pro-inflammatory cytokines. Our findings are consistent with 2 possible roles for ephrin-A1 in melanoma development: it may promote melanocytic cell growth or survival and induce vascularization in advanced melanomas. Both effects may be potentiated by inflammatory responses. Our data are consistent with earlier observations that an inflammatory infiltrate is associated with poor prognosis in thin primary melanomas.

Adenoviral gene transfer of beta3 integrin subunit induces conversion from radial to vertical growth phase in primary human melanoma

Expression of the beta3 subunit of the alphavbeta3 vitronectin receptor on melanoma cells is associated with tumor thickness and the ability to invade and metastasize. To address the role of alphavbeta3 in the complex process of progression from the nontumorigenic radial to the tumorigenic vertical growth phase of primary melanoma, we examined the biological consequences of overexpressing alphavbeta3 in early-stage melanoma cells using an adenoviral vector for gene transfer. Overexpression of functional alphavbeta3 in radial growth phase primary melanoma cells 1) promotes both anchorage-dependent and -independent growth, 2) initiates invasive growth from the epidermis into the dermis in three-dimensional skin reconstructs, 3) prevents apoptosis of invading cells, and 4) increases tumor growth in vivo. Thus, alphavbeta3 serves diverse biological functions during the progression from the nontumorigenic radial growth phase to the tumorigenic and-invasive vertical growth phase primary melanoma.

Molecular events in melanoma development and progression

Based on clinical and histopathological features, five steps of melanoma progression have been proposed: common acquired and congenital nevi with structurally normal melanocytes, dysplastic nevus with structural and architectural atypia, early radial growth phase (RGP) primary melanoma, advanced vertical growth phase primary melanoma (VGP) with competence for metastasis, and metastatic melanoma. Despite a wealth of research resources (tissues, cell lines, and antibodies), the genetic alterations responsible for the development and stepwise progression of melanoma are still unclear. Cytogenetic analyses have failed to identify consistent gene deletions, mutations, translocations, or amplifications in sporadic cases. However, in vitro characterization of melanoma cells has revealed fundamental differences from normal melanocytes. Earlier work using monoclonal antibodies has defined a variety of melanoma-associated antigens that mediate cell-cell or cell-substratum adhesion, growth regulation, proteolysis, and modulation of immune responses. Functional studies of these individual candidate molecules will lead to a better understanding of the pathogenesis of melanoma and of potential targets for rational therapy.

The cell-cell adhesion receptor Mel-CAM acts as a tumor suppressor in breast carcinoma

Mel-CAM (MUC18 or CD146) is a cell adhesion molecule sharing sequence homology with members of the immunoglobulin gene superfamily. Mel-CAM was originally described as a marker associated with invasion and metastasis in melanoma. We determined here the distribution and biological significance of Mel-CAM in normal, benign proliferative, and neoplastic breast ductal epithelium. Using a Mel-CAM-specific monoclonal antibody, we, immunohistochemically demonstrate Mel-CAM expression in 14 of 14 (100%) normal breast epithelia and benign proliferative ductal epithelial lesions, whereas Mel-CAM expression can only be focally detected in 12 of 72 (17%) breast carcinomas. Solid-phase cell adhesion assay revealed that breast carcinoma cells in culture express the ligand for Mel-CAM. Transfection of Mel-CAM cDNA into breast carcinoma cells induces a more cohesive cell growth pattern and establishes smaller tumors in immunocompromised mice than mock transfectants. In conclusion, Mel-CAM is distributed throughout normal and benign proliferative mammary ductal epithelium, but it is frequently lost in carcinomas; it functions as a heterophilic cell-cell adhesion molecule in breast epithelium, and loss of Mel-CAM expression in breast carcinoma may be an important step for tumor progression.

Melanoma cell-cell interactions are mediated through heterophilic Mel-CAM/ligand adhesion

Mel-cell adhesion molecule (CAM), also known as MUC18 and CD146, is a novel member of the immunoglobulin supergene family. Mel-CAM was first identified as an integral membrane glycoprotein in human melanoma and is also abundantly expressed by endothelial cells of various origins. In a previous study (I. M. Shih et al., Cancer Res., 54: 2514-2520, 1994), we showed that Mel-CAM is a cell-cell adhesion molecule with a possible role in melanoma invasion and metastasis. Here, we define the molecular mechanism responsible for cell-cell adhesion of Mel-CAM and demonstrate its role in melanoma-endothelial cell interactions. Most of human melanoma cells, including Mel-CAM-negative SBcl-2 cells, adhered to nitrocellulose-immobilized Mel-CAM produced by baculovirus recombinants. This adhesion can be blocked by full-length Mel-CAM or polyclonal antiserum against Mel-CAM. Adhesion is not affected by the presence of EDTA, truncated Mel-CAM extracellular domain, or heparan sulfate proteoglycan. In cell aggregation assays, Mel-CAM-negative SBcl-2 cells cluster with U937TM cells (U937 transfected with Mel-CAM cDNA) but not with control nontransfectants, suggesting that SBcl-2 cells express the ligand for Mel-CAM. SBcl-2 cells also form heterotypic aggregates with Mel-CAM-positive human endothelial cells but not with Mel-CAM-negative but ligand-positive smooth muscle cells. Taken together, our results show that Mel-CAM mediates cell-cell adhesion through heterophilic adhesion to an as yet unidentified ligand present on melanoma but not on endothelial cells. Thus, melanoma-endothelial interactions during metastasis may occur through this novel mechanism.

Shifts in cadherin profiles between human normal melanocytes and melanomas

Direct contacts between keratinocytes and melanocytes play an important role in conserving the characteristic phenotype and biologic behavior of melanocytic cells. Although the mechanisms involved remain unclear, given the role of adhesion molecules in controlling cellular interactions, disturbances in normal keratinocyte-melanocyte adhesion mediated by cadherin may contribute to malignant transformation by releasing melanocytes from a variety of contact-mediated regulatory controls. To determine the potential clinical relevance of cadherin profiles in melanomas and to study their possible involvement in the phenotypic plasticity of melanocytic cells, we used immunostaining, biochemical, and co-culture techniques. Double immunofluorescence demonstrated expression of cadherins and their associating proteins, alpha- and beta-catenin, in melanocytes in situ. Melanomas were heterogeneous when evaluated immunohistochemically, with positive rates of four of 14, eight of 12, and 12 of 16 to anti-E-, anti-P-, and anti-N-cadherin monoclonal antibodies, respectively. Flow cytometry indicated abundant expression of E-cadherin but marginal P- and N-cadherin in cultured melanocytes. In contrast, only one (WM1232) of 16 melanoma cell lines tested was positive for E-cadherin, none was positive for P-cadherin, and all but one were positive for N-cadherin. Western blot confirmed E-cadherin expression in melanocytic cells. Immunoprecipitation further revealed complexes of E-cadherin with catenins in WM1232 melanoma cells. Co-culture studies indicated that only melanoma cells expressing E-cadherin (WM1232) were susceptible to keratinocyte-mediated control of the expression of the melanoma cell adhesion molecule, Mel-CAM. The results suggest downregulation of E-cadherin but upregulation of N-cadherin in melanoma cells. Such a shift in cadherin profiles may endow melanocytic cells with new adhesive properties and altered spatial relations that favor uncontrolled proliferation, migration, and invasion.

Two recA genes in Myxococcus xanthus

Two recA genes, recA1 and recA2, in Myxococcus xanthus were cloned by using the recA gene of Escherichia coli, and their DNA sequences were determined. On the basis of deduced amino acid sequences, RecA1 and RecA2 have 67.0% identity to each other and 60.5 and 60.9% identities to E. coli RecA, respectively. Expression of recA2 was detected in both vegetative and developmental cells by Northern blot (RNA) analysis, and a threefold induction was observed when cells were treated with nalidixic acid. Repeated attempts to isolate a recA2 disruption mutant have failed, while a recA1 disruption mutant was readily isolated. Both the recA1 and recA2 genes expressed in E. coli complement the UV sensitivity of an E. coli recA strain.

Regulation of Mel-CAM/MUC18 expression on melanocytes of different stages of tumor progression by normal keratinocytes

The cell-cell adhesion receptor, Mel-CAM/MUC18, is highly expressed on metastatic melanoma cells and is also detectable on primary melanomas but not on normal melanocytes. Previous studies have shown that increased Mel-CAM/MUC18 expression correlates with tumor thickness and metastatic potential. We show here that normal melanocytes and nevus cells in culture express Mel-CAM/MUC18, but expression is down-regulated when cells are co-cultured with keratinocytes. Such keratinocyte-mediated regulation of Mel-CAM/MUC18 expression on melanocytes, nevus cells, and early melanomas can also be demonstrated in situ in patients' specimens. On the other hand, melanoma cells from primary and metastatic lesions constitutively express Mel-CAM/MUC18, and keratinocytes have no modulatory effect. These results suggest that contact between keratinocytes and human melanocytic cells modulates Mel-CAM/MUC18 expression, raising the possibility that escape from keratinocyte control during melanoma development leads to expression of antigens that contribute to the malignant phenotype.