Vascular Cellular Adhesion Molecule-1 (VCAM-1) Expression in Mice Retinal Vessels Is Affected by Both Hyperglycemia and Hyperlipidemia

BACKGROUND: Inflammation has been proposed to be important in the pathogenesis of diabetic retinopathy. An early feature of inflammation is the release of cytokines leading to increased expression of endothelial activation markers such as vascular cellular adhesion molecule-1 (VCAM-1). Here we investigated the impact of diabetes and dyslipidemia on VCAM-1 expression in mouse retinal vessels, as well as the potential role of tumor necrosis factor-α (TNFα). METHODOLOGY/PRINCIPAL FINDINGS: Expression of VCAM-1 was examined by confocal immunofluorescence microscopy in vessels of wild type (wt), hyperlipidemic (ApoE(-/-)) and TNFα deficient (TNFα(-/-), ApoE(-/-)/TNFα(-/-)) mice. Eight weeks of streptozotocin-induced diabetes resulted in increased VCAM-1 in wt mice, predominantly in small vessels (<10 µm). Diabetic wt mice had higher total retinal TNFα, IL-6 and IL-1β mRNA than controls; as well as higher soluble VCAM-1 (sVCAM-1) in plasma. Lack of TNFα increased higher basal VCAM-1 protein and sVCAM-1, but failed to up-regulate IL-6 and IL-1β mRNA and VCAM-1 protein in response to diabetes. Basal VCAM-1 expression was higher in ApoE(-/-) than in wt mice and both VCAM-1 mRNA and protein levels were further increased by high fat diet. These changes correlated to plasma cholesterol, LDL- and HDL-cholesterol, but not to triglycerides levels. Diabetes, despite further increasing plasma cholesterol in ApoE(-/-) mice, had no effects on VCAM-1 protein expression or on sVCAM-1. However, it increased ICAM-1 mRNA expression in retinal vessels, which correlated to plasma triglycerides. CONCLUSIONS/SIGNIFICANCE: Hyperglycemia triggers an inflammatory response in the retina of normolipidemic mice and up-regulation of VCAM-1 in retinal vessels. Hypercholesterolemia effectively promotes VCAM-1 expression without evident stimulation of inflammation. Diabetes-induced endothelial activation in ApoE(-/-) mice seems driven by elevated plasma triglycerides but not by cholesterol. Results also suggest a complex role for TNFα in the regulation of VCAM-1 expression, being protective under basal conditions but pro-inflammatory in response to diabetes

Frequency and examples of code breaches found by the IGM or NBL in antidepressant advertisements in the Swedish Medical Journal in 1994–2003.

<p>See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062609#pone.0062609.s003" target="_blank">Table S2</a> for complete list of relevant articles.</p>1<p>Refers to IGM/NBL cases. Note that some cases revealed more than one type of article breach: see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0062609#pone.0062609.s002" target="_blank">Table S1</a>.</p>2<p>A few ads had contents ruled in violation in multiple cases.</p>3<p>Case numbers in the IGM/NBL database are indicated.</p>4<p>Percentage in cell of total, e.g. 13% of IGM/NBL cases, 4.8% of unique ads, and 5.1% of total ads breached article 1.</p

Statements in antidepressant advertisements advancing general or comparative efficacy in depression treatment, or professing monoamine theories.

1<p>Number of ads containing claims or theories/number of ads found in breach by the IGM/NBL for this, e.g. 16 unique ads professed general efficacy claims; zero were found to be in violation for this.</p>2<p>Percentage of ads containing claims or theories of total, e.g. 12.9% of 124 unique advertisements professed general efficacy claims.</p>3<p>Percentage of ads found in breach by the IGM/NBL of ads containing claims or theories, e.g. 16 unique ads professed general efficacy claims; zero percent were found to be in violation for this.</p>4<p>Italicized statements were found to breach the code by the IGM/NBL. Case number in the IGM/NBL database is indicated.</p

Lags in the system allowed for extended and substantial exposure to unethical antidepressant advertising.

<p>The instigator of each IGM/NBL case is indicated; HP (health professionals), MPA (Medical Products Agency). (A) Scatter plot of reaction times (i.e. the elapsed time between original publication date and date of ruling against wrongful claims) among IGM/NBL cases concerning antidepressant advertising in the Swedish Medical Journal in 1994–2003. Linear regression analysis shows that reaction times increased over the ten-year period (p = 0.041; β = 6.9 weeks/year; n = 23). (B) Scatter plot of the total number of violative advertisements in the Swedish Medical Journal per IGM/NBL case prior to date of ruling. Linear regression analysis shows that there was a borderline significant increase in the number of advertisements allowed in print over the period (p = 0.063; β = 1.4 ads/year; n = 23). (C) Reaction times and (D) number of violative advertisements among cases instigated by the IGM (i.e. via active monitoring of promotional material) and non-IGM (i.e. following voluntary complaints from industry, HP or the MPA), respectively. The median of each group is indicated by the bar. Differences between groups were analyzed with two-tailed Mann-Whitney test. There was a significant difference in reaction time between IGM and non-IGM cases (p = 0.007) (in C).</p

Flow through the Swedish complaints system for medicines promotion.

<p>(A) Outline of the Swedish self-regulatory system. The Pharmaceutical Industry’s Information Examiner (IGM) monitors industry promotional material for potential code breaches. The IGM also handles complaints from health professionals (HP), pharmaceutical companies and the general public. Offending companies are sanctioned by the IGM. Besides handling appeals of IGM decisions, the Information Practices Committee (NBL) considers complaints from public authorities, such as the Medical Products Agency (MPA), and sanctions code breaches. (B) Overview of the flow of cases concerning antidepressant advertising in the Swedish Medical Journal in 1994–2003 including number of cases instigated by various actors. Of the 24 cases considered by the IGM/NBL, 23 were found to be in violation.</p

Antidepressant sales in Sweden and advertising dynamics in the Swedish Medical Journal.

<p>(A) Graphs show antidepressant sales (in EUR million) (dotted line) in Sweden in 1991–2011 and total antidepressant advertisements (red unbroken line) in the Swedish Medical Journal in 1994–2003. Spending on antidepressants rose steeply between 1993 and 1996, as well as between 1999 and 2001, but subsequently plateaued and started falling, coinciding with a drop in antidepressant advertising. (B) Declining antidepressant spending (dotted line) and advertising did not coincide with a drop in prescriptions (unbroken line), but instead coincided with price cuts due to major patent expiries. (C) Graphs show total (red line) and violative (black line) antidepressant advertising in the Swedish Medical Journal in 1994–2003.</p

Type and frequency of serious violation rulings: diabetes drugs and urologics.

<p>^aCase number ID: see <a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001785#pmed.1001785.s006" target="_blank">S5</a>–<a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001785#pmed.1001785.s009" target="_blank">S8</a> Tables for additional information.</p><p>ADR, adverse drug reaction; IGT, impaired glucose tolerance.</p><p>Type and frequency of serious violation rulings: diabetes drugs and urologics.</p

Sweden rulings of breach of selected clauses 2004–2012.

<p>^aPercentages indicate cell portion of total breaches. E.g., 16% of breaches pertained to §2.</p><p>^bPercentages indicate cell portion of total cases. E.g., 29% of cases involved one or more §2 ruling.</p><p>^cPercentages indicate cell portion of total serious violation cases. E.g., 49% of serious violation cases involved one or more §2 ruling.</p><p>Sweden rulings of breach of selected clauses 2004–2012.</p

Complaints, rulings of breach, and complainants in the United Kingdom and Sweden 2004–2012.

<p>(A) and (B) show the number of registered complaints and cases ruled in breach in the UK and Sweden, respectively (total registered complaints: <i>n</i> = 933 in UK, <i>n</i> = 916 Sweden; total cases ruled in breach: <i>n</i> = 597 in UK, <i>n</i> = 536 in Sweden). (A) also shows matters in breach in the UK (<i>n</i> = 1368). (C) Statutory copies of drug promotion sent by companies in Sweden to the IGM for scrutiny in 1998–2012 (<i>n</i> = 59,158). Dashed line indicates year 2004. (D) shows mosaic plot of registered complaints by type of complainant in each country.</p