RAGE Staining Research Articles

Blocking RAGE expression after injury reduces inflammation in mouse model of acute lung injury

BackgroundReceptor for Advanced Glycated Endproducts (RAGE) plays a major role in the inflammatory response to infectious and toxin induced acute lung injury. We tested the hypothesis that a RAGE blocking antibody when administered after the onset of injury can reduce lung inflammation compared to control antibody.MethodsMale and female C57BL/6 (WT) mice were used. Forty-six received lipopolysaccharide (LPS) and 26 PBS by nasal instillation on day one, repeated on day three. On day 2, 36 mice receiving LPS were divided into two groups of 18, one treated with 200 μg of non-immune isotype control IgG and the second group treated with 200 μg of anti-RAGE Ab, each dose divided between IV and IP. Ten of the 46 were not treated. On day 4, before euthanasia, mice were injected with fluorescein isothiocyanate (FITC) labelled albumen. BALF and serum samples were collected as well as lung tissue for immunohistochemistry (IHC). BALF was analyzed for cell (leukocyte) counts, for FITC BALF/serum ratios indicating pulmonary vascular leak, and for cytokines/chemokines using bead based multiplex assays. Quantitative IHC was performed for MPO and RAGE.ResultsTen LPS mice showed minimal inflammation by all measures indicating poor delivery of LPS and were excluded from analysis leaving n = 11 in the LPS + IgG group and n = 12 in the LPS + anti-RAGE group. BALF cell counts were low in the PBS administered mice (4.9 ± 2.1 × 105/ml) and high in the LPS injured untreated mice (109 ± 34) and in the LPS + IgG mice (91 ± 54) while in comparison, LPS + anti-RAGE ab mice counts were significantly lower (51.3 ± 18 vs. LPS + IgG, P = 0.03). The BALF/serum FITC ratios were lower for the LPS + anti-RAGE mice than for the LPS + IgG mice indicating less capillary leakiness. Quantitative IHC RAGE staining was lower in the LPS + anti-RAGE ab mice than in the LPS + IgG treated mice (P = 0.02).ConclusionsThese results describe a four-day LPS protocol to sustain lung injury and allow for treatment and suggests that treatment aimed at blocking RAGE when given after onset of injury can reduce lung inflammation.

Polydatin Alleviates Diabetes-Induced Hyposalivation through Anti-Glycation Activity in db/db Mouse.

Polydatin (resveratrol-3-O-β-mono-D-glucoside) is a polyphenol that can be easily accessed from peanuts, grapes, and red wine, and is known to have antiglycation, antioxidant, and anti-inflammatory effects. Diabetes mellitus is a very common disease, and diabetic complications are very common complications. The dry mouth symptom is one of the most common oral complaints in patients with diabetes mellitus. Diabetes mellitus is thought to promote hyposalivation. In this study, we aimed to investigate the improvement effect of polydatin on diabetes-induced hyposalivation in db/db mouse model of type 2 diabetes. We examined salivary flow rate, TUNEL assay, PAS staining, and immunohistochemical staining for AGEs, RAGE, HMGB1, 8-OHdG, and AQP5 to evaluate the efficacy of polydatin in the submandibular salivary gland. Diabetic db/db mice had a decreased salivary flow rate and salivary gland weight. The salivary gland of the vehicle-treated db/db mice showed an increased apoptotic cell injury. The AGEs were highly accumulated, and its receptor, RAGE expression was also enhanced. Expressions of HMGB1, an oxidative cell damage marker, and 8-OHdG, an oxidative DNA damage marker, increased greatly. However, polydatin ameliorated this hypofunction of the salivary gland and inhibited diabetes-related salivary cell injury. Furthermore, polydatin improved mucin accumulation, which is used as a damage marker for salivary gland acinar cells, and decreased expression of water channel AQP5 was improved by polydatin. In conclusion, polydatin has a potent protective effect on diabetes-related salivary gland hypofunction through its antioxidant and anti-glycation activities, and its AQP5 upregulation. This result suggests the possibility of the use of polydatin as a therapeutic drug to improve hyposalivation caused by diabetes.

Novel Receptor for Advanced Glycation End Products-Blocking Antibody to Treat Diabetic Peripheral Artery Disease.

BackgroundExpression of receptor for advanced glycation end products (RAGE) plays an important role in diabetic peripheral artery disease. We proposed to show that treatment with an antibody blocking RAGE would improve hind limb perfusion and muscle viability in diabetic pig with femoral artery (FA) ligation.Methods and ResultsPurpose‐bred diabetic Yucatan minipigs with average fasting blood sugar of 357 mg/dL on insulin to maintain a glucose range of 300 to 500 mg/dL were treated with either a humanized monoclonal anti‐RAGE antibody (CR‐3) or nonimmune IgG. All pigs underwent intravascular occlusion of the anterior FA. Animals underwent (201Tl) single‐photon emission computed tomography/x‐ray computed tomography imaging on days 1 and 28 after FA occlusion, angiogenesis imaging with [99mTc]dodecane tetra‐acetic acid–polyethylene glycol–single chain vascular endothelial growth factor (scVEGF), muscle biopsies on day 7, and contrast angiogram day 28. Results showed greater increases in perfusion to the gastrocnemius from day 1 to day 28 in CR‐3 compared with IgG treated pigs (P=0.0024), greater uptake of [99mTc]dodecane tetra‐acetic acid‐polyethylene glycol‐scVEGF (scV/Tc) in the proximal gastrocnemius at day 7, confirmed by tissue staining for capillaries and vascular endothelial growth factor A, and less muscle loss and fibrosis at day 28. Contrast angiograms showed better reconstitution of the distal FA from collaterals in the CR‐3 versus IgG treated diabetic pigs (P=0.01). The gastrocnemius on nonoccluded limb at necropsy had higher 201Tl uptake (percentage injected dose per gram) and reduced RAGE staining in arterioles in CR‐3 treated compared with IgG treated animals (P=0.04).ConclusionsA novel RAGE‐blocking antibody improved hind limb perfusion and angiogenesis in diabetic pigs with FA occlusion. Contributing factors are increased collaterals and reduced vascular RAGE expression. CR‐3 shows promise for clinical treatment in diabetic peripheral artery disease.

Lung adenocarcinoma expressing receptor for advanced glycation end-products with primary systemic AL amyloidosis: a case report and literature review

BackgroundReceptor for advanced glycation end-products (RAGE), a receptor for amyloids, is constitutively expressed in lungs and generally observed to be downregulated in lung cancer tissues. However, increasing levels of RAGE or serum amyloids is associated with poor outcome in lung cancer patients. We report a rare case of primary systemic amyloid light-chain (AL) amyloidosis in biopsy-proven multiple organs with early-stage non-small cell lung cancer (NSCLC) that displayed strong staining for RAGE in the tumour tissue. Interestingly, compared with randomly selected lung cancer biopsy samples, including all representative histological subtypes of NSCLC and small-cell lung cancer, only the NSCLC in the present case showed strong expression for RAGE that can bind amyloids.Case presentationA 71-year-old woman was admitted to our hospital for comprehensive investigation of nephrotic syndrome. Computed tomography showed a small nodule in the right upper lung lobe with hilar mediastinal lymph node enlargement. Pathological examination of transbronchial biopsy samples of the nodule yielded a diagnosis of lung adenocarcinoma. Furthermore, the pathological detection of amyloid deposition in biopsy samples of a subcarinal lymph node, gastric and duodenal mucosa, cardiac muscle, and bone marrow led to a diagnosis of primary systemic AL amyloidosis with nephrotic syndrome and cardiomyopathy. In addition, RAGE was detected in lung tumour tissues surrounded by normal lung tissues with amyloid deposition.ConclusionThe RAGE positivity of the lung cancer cells in this case suggests an interaction between amyloid-containing tissues and RAGE-expressing cancer cells. Lung adenocarcinoma with RAGE expression may be a complication of underlying amyloidosis.

Dietary glycotoxins induce RAGE and VEGF up-regulation in the retina of normal rats

Exogenous intake of glycotoxins present in western diet accelerates the accumulation of advanced glycation end products (AGEs) in multiple organs leading to potential tissue damage. Advanced ageing and diabetic conditions have been associated with AGEs deposition in multiple eye compartments including Bruch's membrane, optic nerve, lens and cornea. However, the impact of dietary AGEs in ocular physiology has not been extensively studied. The present study investigates the direct effects of a high AGE content diet in the ocular tissues of normal rats of different age. Two groups of baby (4 weeks of age) and adult (12 weeks of age) female Wistar rats (n = 73) were allocated to high- or low-AGE diet for 3 months. Upon completion of experimental protocol, somatometric, hormonal and biochemical parameters were evaluated in all groups. Circulating and tissue AGE levels were estimated along with their signaling receptor (receptor for AGEs, RAGE) and vascular endothelial growth factor A (VEGF-A) expression in ocular tissues of the different subgroups. High AGE intake was associated with elevated serum AGEs (p = 0.0001), fructosamine (p = 0.0004) and CRP levels (p = 0.0001) compared to low AGE. High peripheral AGE levels were positively correlated with significant increased tissue immunoreactivity of AGEs and RAGE in retinal and uveal tissues as well as retinal VEGF-A expression. Up-regulation of RAGE and VEGF-A expression was observed in the ocular tissue of both baby and adult animals fed with high-AGE diet. Co-localization of AGEs and RAGE staining was observed mainly in the inner retinal layers and the retinal pigment epithelium (RPE) of all groups. VEGF-A expression was elevated in the RPE, the inner nuclear layer and the retinal ganglion cell layer of the animals exposed to high-AGE diet. In conclusion, dietary AGEs intake affects the physiology of ocular tissues by up-regulating RAGE and VEGF-A expression contributing to enhanced inflammatory responses and pathologic neovascularization in normal organisms independent of ageing.

Advanced glycation end-product expression is upregulated in the gastrointestinal tract of type 2 diabetic rats.

To investigate changes in advanced glycation end products (AGEs) and their receptor (RAGE) expression in the gastrointestinal (GI) tract in type 2 diabetic rats. Eight inherited type 2 diabetic rats Goto-Kakizak (GK) and ten age-matched normal rats were used in the study. From 18 wk of age, the body weight and blood glucose were measured every week and 2 wk respectively. When the rats reached 32 wk, two-centimeter segments of esophagus, duodenum, jejunum, ileum, and colon were excised and the wet weight was measured. The segments were fixed in 10% formalin, embedded in paraffin and five micron sections were cut. The layer thickness was measured in Hematoxylin and Eosin-stained slides. AGE [N epsilon-(carboxymethyl) lysine and N epsilon-(carboxyethyl)lysine] and RAGE were detected by immunohistochemistry staining and image analysis was done using Sigmascan Pro 4.0 image analysis software. The blood glucose concentration (mmol/L) at 18 wk age was highest in the GK group (8.88 ± 1.87 vs 6.90 ± 0.43, P < 0.001), a difference that continued to exist until the end of the experiment. The wet weight per unit length (mg/cm) increased in esophagus, jejunum and colon from the normal to the GK group (60.64 ± 9.96 vs 68.56 ± 11.69, P < 0.05 for esophagus; 87.01 ± 9.35 vs 105.29 ± 15.45, P < 0.01 for jejunum; 91.37 ± 7.25 vs 97.28 ± 10.90, P < 0.05 for colon). Histologically, the layer thickness of the GI tract was higher for esophagus, jejunum and colon in the GK group [full thickness (μm): 575.37 ± 69.22 vs 753.20 ± 150.41, P < 0.01 for esophagus; 813.51 ± 44.44 vs 884.81 ± 45.31, P < 0.05 for jejunum; 467.12 ± 65.92 vs 572.26 ± 93.60, P < 0.05 for colon]. In esophagus, the AGE and RAGE mainly distributed in striated muscle cells and squamous epithelial cells. The AGE distribution was much stronger in the GK group compared to the normal group both in the striated muscle layer and mucosa layer (immuno-positive area/ total measuring area %: 4.52 ± 0.89 vs 10.96 ± 1.34, P < 0.01 for muscle; 8.90 ± 2.62 vs 22.45 ± 1.26, P < 0.01 for mucosa). No visible difference was found for RAGE distribution between the two groups. In the intestine AGE and RAGE distributed in epithelial cells of villi and crypt. RAGE was also found in neurons in the myenteric and submucosal plexus. The intensity of AGE staining in mucosa of all segments and RAGE staining in neurons in all segments were strongest in the diabetes group. Significant difference for AGE was found in the epithelial cells of villi and crypt in duodenum (immuno-positive area/total measuring area %: 13.37 ± 3.51 vs 37.48 ± 8.43, P < 0.05 for villi; 0.38 ± 0.12 vs 1.87 ± 0.53, P < 0.05 for crypt) and for RAGE in neurons of all segments (e.g., for jejunum: no staining neurons% 0 vs 0, mild 36.0 ± 5.2 vs 28.7 ± 3.5, moderate 53.2 ± 4.8 vs 55.8 ± 5.4, strong 10.7 ± 1.1 vs 15.4 ± 2.0, P < 0.05). In the colon, RAGE was primarily found in neurons in the myenteric and submucosal plexus. It was stronger in the diabetes group than in the normal group (no staining neurons% 6.2 ± 0.2 vs 0.3 ± 0.04, mild 14.9 ± 2.1 vs 17.6 ± 1.5, moderate 53.1 ± 4.6 vs 44.7 ± 4.4, strong 25.6 ± 18 vs 43.6 ± 4.0, P < 0.05). In the rectum, RAGE was primarily found in the mucosa epithelial cells. The AGE and RAGE expression was up-regulated in the GI tract of GK diabetic rats and may contribute to GI dysfunction in type 2 diabetic patients.

Imaging RAGE expression in atherosclerotic plaques in hyperlipidemic pigs.

BackgroundReceptor for advanced glycated end product (RAGE) expression is a prominent feature of atherosclerosis. We have previously shown in apoE null mice uptake of a radiolabeled anti-RAGE antibody in atherosclerotic plaque and now evaluate RAGE-directed imaging to identify advanced plaques in a large animal model.MethodsNine hyperlipidemic (HL) pigs were injected with 603.1 ± 129.5 MBq of 99mTc-anti-RAGE F(ab′)2, and after 6 h (blood pool clearance), they underwent single-photon emission computed tomography/computed tomography (SPECT/CT) imaging of the neck, thorax, and hind limbs. Two HL pigs received 99mTc non-immune IgG F(ab′)2, and three farm pigs were injected with 99mTc-anti-RAGE F(ab′)2. After imaging, the pigs were euthanized. The aorta from the root to bifurcation was dissected, and the innominates, proximal carotids, and coronaries were dissected and counted, stained for H&E and RAGE, and AHA-classified.ResultsOn pathology, 24% of the arterial segments showed AHA class III or IV lesions, and these lesions were confined almost exclusively to coronaries and carotids with % stenosis from 15% to 65%. Scatter plots of %ID/g for class III/IV vs. I/II lesions showed almost complete separation. Focal vascular uptake of tracer visualized on SPECT scans corresponded to class III/IV lesions in the coronary and carotid vessels. In addition, uptake in the hind limbs was noted in the HL pigs and corresponded to RAGE staining of small arteries in the muscle sections. Correlations for the vascular lesions were r = 0.747, P = 0.001 for %ID vs. %ID/g and r = 0.83, P = 0.002 for %ID/g vs. % RAGE staining.ConclusionsUptake of radiolabeled anti-RAGE antibody in coronary and carotid fibroatheroma and in the small arteries of the hind limbs in a relevant large animal model of atherosclerosis supports the important role of RAGE in atherosclerosis and peripheral artery disease as a target for imaging and treatment.

Histology of liver oxidative stress in an obese mouse model of nonalcoholic fatty liver disease treated with Ω3 fatty acids, TNFα‐receptor blocker, or curcumin (1116.1)

Nonalcoholic fatty liver disease (NAFLD) origins are unclear but progression involves inflammation and correlation with obesity and insulin resistance. Advanced glycation end products (AGEs) are oxidative stress markers that induce inflammation and release reactive oxygen species. AGEs play key roles in the development of vascular inflammation of many types. Tissue accumulation of AGEs is identified by receptor staining (RAGE) . This study evaluated dietary and drug intervention to interrupt RAGE staining in a model of NAFLD. OB/OB leptin knock‐out mice (10/group) received clinical levels of curcumin, Ω3 fatty acids, TNF‐α receptor blocker or control chow for 8 wk. Liver steatosis was scored at 400x. Liver was also stained with PAS for glycoproteins and RAGE antibody. The Image J program was used for quantification of RAGE stain percentage. By H&amp;E, significant reduction of liver fat was seen in groups receiving curcumin or Ω‐3 fatty acids compared to controls. By RAGE stain, interventions reduced AGES from 38.1% (untreated) to 26.4% (TNF blocker) and 26.8% (Ω3). p value, 0.15. This pilot experiment suggests that AGEs contribute to the development of nonalcoholic fatty liver disease and/or the progression of NAFLD to nonalcoholic steatohepatitis. The progression, in our model, is interrupted by food additives or an anti‐inflammatory. Studies to expand this approach to interrupt NAFLD are planned.Grant Funding Source: Funding: St Luke’s Hospital Foundation grant to LA

Up-regulation of the receptor for advanced glycation end products in the skin biopsy specimens of patients with severe diabetic neuropathy.

Background and PurposeThe receptor for advanced glycation end products (RAGE) may contribute to the development of diabetic neuropathy. To assess its relevance in humans, this study examined the expression of RAGE in the skin biopsy samples of patients with diabetes mellitus, and investigated its correlation with intraepidermal nerve-fiber density (IENFD) and clinical measures of neuropathy severity.MethodsForty-four patients who either had type 2 diabetes or were prediabetes underwent clinical evaluation and a 3-mm skin punch biopsy. The clinical severity of their neuropathy was assessed using the Michigan Diabetic Neuropathy Score. IENFD was measured along with immunohistochemical staining for RAGE in 29 skin biopsy samples. The expression of RAGE was also quantified by real-time reverse-transcription PCR in the remaining 15 patients.ResultsRAGE was localized mostly in the dermal and subcutaneous vascular endothelia. The staining was more intense in patients with a lower IENFD (p=0.004). The quantity of RAGE mRNA was significantly higher in patients with severe neuropathy than in those with no or mild neuropathy (p=0.003). The up-regulation of RAGE was related to dyslipidemia and diabetic nephropathy. There was a trend toward decreased sural nerve action-potential amplitude and slowed peroneal motor-nerve conduction with increasing RAGE expression.ConclusionsThe findings of this study demonstrate up-regulation of RAGE in skin biopsy samples from patients with diabetic neuropathy, supporting a pathogenic role of RAGE in the development of diabetic neuropathy.

Abstract 422: Atherosclerosis and Rage Expression by Histology and Imaging in Hyperlipidemic Pigs

Purpose and methods To characterize atherosclerotic lesions and RAGE expression in a large animal model and investigate targeting RAGE for in-vivo imaging. Nine hyperlipidemic pigs at 12 mo of age were studied. LDL averaged 513 ± 74 mg/dL and final wt was 63.3 ± 12.4 kg. Pigs were injected with 16.3 ± 3.5 mCi of 99m Tc anti-RAGE F(ab’) 2 and after 8 hr (blood pool clearance) underwent SPECT/CT imaging of the neck and thorax and then euthanized, the aorta including innominate, proximal carotids, and proximal ileofemoral branches and coronaries were dissected. Vascular tissue was divided into 36 anatomical segments: coronaries: 4 each x 3 = 12, aortic root: 3, aortic arch: 4, thoracic aorta: 3 and abdominal aorta: 3, each carotid and femoral: 2. Sections from each segment were counted and stained for H&amp;E and RAGE. Scans were analyzed for tracer uptake in organs and vascular structures and counts converted in %ID. All sections were classified according to AHA criteria, % stenosis, and % RAGE staining was quantified. One HL pig received non-immune control antibody and 2 farm pigs were injected for blood pool clearance and SPECT imaging. Results On pathological examination 75/324 segments or 23% showed class 2 lesion or greater. All class III or IV lesions were in the coronaries, carotids, and femoral arteries and % stenosis ranged from 16 to 65%. In vivo biodistribution showed intense uptake of the antibody in the lungs (15 %ID) indicating high constitutive expression of RAGE and precluded visualizing the thoracic aorta. Heart uptake was low (1.3 x 10 -4 %ID) providing visualization of focal coronary uptake and the carotids were well seen. Focal tracer uptake was visualized on SPECT scans in these 2 vascular territories for all vessels with class III or IV lesions and uptake ranged from 4 -22 %ID x 10 -4 . Correlations were R = 0.85, P = 0.002 for %ID vs. %ID/g and R = 0.83, P = 0.002 for %ID/g vs. % RAGE staining. Conclusions There is variability in extent and severity of atherosclerotic disease in HL pigs at one year. RAGE staining is found in all class II-IV lesions and correlated with uptake of radiolabeled antibody targeting RAGE. High RAGE expression in lungs limited imaging the aorta but carotid and coronary artery uptake was seen on SPECT scans.

Role of the advanced glycation end products receptor in Crohn’s disease inflammation

To investigate the level of mucosal expression and the involvement of the receptor for the advanced glycation end products (RAGE) in delayed apoptosis and tumor necrosis factor (TNF)-α production in Crohn's disease (CD). Surgical and endoscopic specimens from both inflamed and non-inflamed areas of the ileum and/or colon were collected from 20 and 14 adult CD patients, respectively, and used for the assessment of RAGE expression by means of immunohistochemistry and western blotting analysis. Normal tissues from 21 control subjects were used for comparison. The same polyclonal anti-human RAGE antibody (R and D System) was used in all experimental conditions. RAGE staining was quantized by a score including both the amount of positive cells and intensity of immunoreactivity; cellular pattern was also described. The effects of RAGE blocking on apoptotic rate and TNF-α production were investigated on immune cells freshly isolated from CD mucosa and incubated both with and without the muramyl dipeptide used as antigenic stimulus. Statistical analysis was performed via the test for trend, with regression models to account for intra-patient correlations. A 2-sided P < 0.05 was considered significant. In inflamed areas, RAGE expression in both the epithelial and lamina propria compartments was higher than control tissues (P = 0.001 and 0.021, respectively), and a cluster of positive cells were usually found in proximity of ulcerative lesions. Similar results were obtained in the lamina propria compartment of non-inflamed areas (P = 0.025). The pattern of staining was membranous and granular cytosolic at the epithelial level, while in the lamina propria it was diffuse cytosolic. When evaluating the amount of protein expression by immunoblotting, a significant increase of both surface area and band intensity (P < 0.0001 for both) was observed in CD inflamed areas compared to control tissue, while in non-inflamed areas a significant increase was found only for band intensity (P < 0.005). Moreover, a significantly lower expression in non-inflamed areas in comparison with inflamed areas was found for both surface area and band intensity (P < 0.0006 for both). Finally, RAGE blocking largely affects both the apoptotic rate of mucosal cells (towards an increase in both non-inflamed and inflamed areas of P < 0.001 and < 0.0001, respectively) and TNF-α secretion (towards a decrease in both non-inflamed and inflamed areas of P < 0.05 and < 0.01, respectively), mainly in the presence of antigenic stimulation. RAGE is up-regulated in CD, especially in inflamed areas, and it appears to play a role in the mechanisms involved in chronic inflammation.

Imaging of Receptors for Advanced Glycation End Products in Experimental Myocardial Ischemia and Reperfusion Injury

The aim of this study was to image expression of receptor for advanced glycation end products (RAGE) in a mouse model of myocardial reperfusion injury. RAGE and its ligands are implicated in the pathogenesis of ischemia/reperfusion injury and infarction. We hypothesized that RAGE-directed quantitative imaging of myocardial uptake of technetium-99m ((99m)Tc)-anti-RAGE F(ab')(2) in a mouse model of myocardial ischemic injury can detect RAGE expression and show quantitative differences between early (18 to 20 h) and later times (48 h) after reperfusion. Twenty-five wild-type (WT) mice underwent left anterior descending coronary artery occlusion for 30 min. Mice were injected with 19.98 ± 1.78 MBq of (99m)Tc anti-RAGE F(ab')(2) at 2 time points after reperfusion (at 18 to 20 h [n = 8] and at 48 h [n = 12]) and 5 h later with 6.14 ± 2.0 MBq of thallium-201 ((201)Tl). Five WT mice were injected with nonspecific F(ab')(2) and (201)Tl 18 to 20 h after reperfusion. Six WT mice underwent sham operation without coronary intervention. After injection with (201)Tl, all mice immediately underwent dual isotope single-photon emission computed tomography/computed tomography. At completion of imaging, hearts were counted and sectioned. The uptake of (99m)Tc-anti-RAGE F(ab')(2) in the ischemic zone from the scans as mean percentage injected dose was significantly greater at 18 to 20 h (5.7 ± 2.1 × 10(-3)%) as compared with at 48 h (1.4 ± 1.1 × 10(-3)%; p < 0.001) after reperfusion. Disease and antibody controls showed no focal uptake in the infarct. Gamma well counting of the myocardium supported the quantitative scan data. By immunohistochemical staining there was greater caspase-3 and RAGE staining at 18 to 20 h versus at 48 h (p = 0.04 and p = 0.01, respectively). On dual immunofluorescence, RAGE colocalized mainly with injured cardiomyocytes undergoing apoptosis. RAGE expression in myocardial ischemic injury can be imaged in vivo using a novel (99m)Tc-anti-RAGE F(ab')(2). RAGE plays a role in several cardiovascular diseases and is a potential target for clinical imaging.

Development of pulmonary arterial hypertension in mice over-expressing S100A4/Mts1 is specific to females

BackgroundIdiopathic and familial forms of pulmonary arterial hypertension (PAH) occur more frequently in women than men. However, the reason for this remains unknown. Both the calcium binding protein S100A4/Mts1 (Mts1) and its endogenous receptor (receptor for advanced glycosylation end products; RAGE) have been implicated in the development of PAH. We wished to investigate if the Mts1/RAGE pathway may play a role in the gender bias associated with PAH.MethodsWe investigated the effects of gender on development of PAH in mice over-expressing Mts1 (Mts1+ mice) via measurement of pulmonary arterial remodeling, systolic right ventricular pressure (sRVP) and right ventricular hypertrophy (RVH). Gender differences in pulmonary arterial Mts1 and RAGE expression were assessed by qRT-PCR and immunohistochemistry. Western blotting and cell counts were used to investigate interactions between 17β-estradiol, Mts1 and RAGE on proliferation of human pulmonary artery smooth muscle cells (hPASMCs). Statistical analysis was by one-way analysis of variance with Dunnetts post test or two-way analysis of variance with Bonferronis post test, as appropriate.ResultsFemale Mts1+ mice developed increased sRVP and pulmonary vascular remodeling, whereas male Mts1+ mice remained unaffected. The development of plexiform-like lesions in Mts1+ mice was specific to females. These lesions stained positive for both Mts1 and RAGE in the endothelial and adventitial layers. Expression of pulmonary arterial Mts1 was greater in female than male Mts1+ mice, and was localised to the medial and adventitial layers in non plexiform-like pulmonary arteries. RAGE gene expression and immunoreactivity were similar between male and female Mts1+ mice and RAGE staining was localised to the endothelial layer in non plexiform-like pulmonary arteries adjacent to airways. In non-plexiform like pulmonary arteries not associated with airways RAGE staining was present in the medial and adventitial layers. Physiological concentrations of 17β-estradiol increased Mts1 expression in hPASMCs. 17β-estradiol-induced hPASMC proliferation was inhibited by soluble RAGE, which antagonises the membrane bound form of RAGE.ConclusionsMts1 over-expression combined with female gender is permissive to the development of experimental PAH in mice. Up-regulation of Mts1 and subsequent activation of RAGE may contribute to 17β-estradiol-induced proliferation of hPASMCs.

Fixed Weight Based Thiopurine Dosing Lowers Steroid Free Remission Rates in Crohn's Disease

G A A b st ra ct s 2008;20:629). We hypothesized effectiveness of GMA and LMA might be dependent on depletion of granulocyte and monocytes. S100A12 was reported to be exclusively expressed in neutrophils and up-regulated by TNF α. The aim of this study was to investigate the changes of serum S100 A12 concentration in the GMA treatments and whether S100A12 increases the expression of adhesion molecules, CXCL and CCL chemokines. Methods; 24 patients with ulcerative colitis were treated with GMA. Serum S100A12 was estimated by ELISAmethods. Clinical activity index (CAI) and serumCRP concentrationwere also checked. Immunohistochemical staining of S100A12 and receptor for advanced glication end products (RAGE) were performed in the operated specimens of patients with ulcerative colitis and with colonic carcinoma (control). HUVEC were seeded into 12 well plates and confluent plates were used to experiments. Each experiment was performed in triplicate. HUVEC were treated with human recombinant S100A12 protein. RNA was extracted by RNeasy Mini Kit. 1.5μg RNA was reverse-transcriptated into cDNA. ICAM-1, VCAM-1, IL-8, CCL-2 (MCP1), CCL5 (RANTES), CXCL9 (IP-10) and CXCL10 (Mig) mRNA was quantitated by realtime PCR. Results; S100A12 staining was faintly recognized in the mucosal layer of normal control. S100A12 staining was increased in infiltrating cells in inflamed colon in patients with ulcerative colitis. Strong staining was also recognized in crypt abscess. RAGE staining was also faintly recognized in the epithelial cells in nornmal control. However, RAGE staining was increased in the inflamed epithelial cells. Significantly serum S100A12 concentration was positively correlated with CAI (n=34, p=0.02, rs=0.404). 16 patients were able to estimate S100A12 concentration in the points of preand post-GMA treatment. 13 patients were GMA-responders and 3 patients were non GMA-responders. Serum S100A12 concentration was significantly decreased in GMA responders (prevs postGMA, 1.34±1.08 vs 0.60±0.50, p<0.05). However, Serum S100A12 concentration of non GMAresponders was gradually increased with GMA treatments. ICAM-1, VCAM-1, IL-8, IP-10, Mig, MCP-1 and RANTES mRNA expressions were increased by S100A12 in HUVEC cell lines in time and dose-dependent manners. Conclusion; one of the mechanisms of GMA effect might be correlated with depletion of S100A12 by adsorption of activated neutrophils. S100A12 might aggravate acute and chronic inflammation by up-regulation of adhesion molecules, CXCL and CCL chemokines.

Peroxisome proliferator-activated receptor-γ activation attenuates cardiac fibrosis in type 2 diabetic rats: the effect of rosiglitazone on myocardial expression of receptor for advanced glycation end products and of connective tissue growth factor

Receptor for advanced glycation end products (RAGE) and connective tissue growth factor (CTGF) play a key role in diabetic myocardial fibrosis, and peroxisome proliferator-activated receptor-gamma (PPAR-gamma) activation has been reported to reduce RAGE and CTGF expression. This study investigated the effects of the PPAR-gamma agonist, rosiglitazone, on myocardial expression of RAGE and CTGF, extent of cardiac fibrosis, and left ventricular (LV) diastolic function in type 2 diabetic (T2D) rats. Twenty-week-old T2D rats were randomized to treatment with either 20 weeks of rosiglitazone (20 mg/kg) or saline (n = 10 in each group). Serial echocardiographic examinations were performed just before randomization (20 weeks) and at study completion (40 weeks). Fibrosis extent and RAGE and CTGF expression were assessed in previously imaged hearts by picrosirius red staining, and by real-time reverse transcriptase-coupled polymerase chain reaction (RT-PCR) and immunoblotting, respectively. Results of the latter assessments were further validated by immunohistochemical staining. Rosiglitazone treatment significantly improved E/A ratio in serial echocardiography assessment, and reduced LV collagen volume fraction as demonstrated by picrosirius red staining. Real-time RT-PCR and immunoblots of myocardial tissue from rosiglitazone-treated rats revealed reduced RAGE and CTGF mRNA and protein signals compared to those of saline-treated T2D rats, which were consistent with reduced proportions of myocardial RAGE and CTGF staining in the hearts of T2D rats. PPAR-gamma agonist therapy reduces cardiac fibrosis and improves LV diastolic dysfunction as assessed by serial echocardiographic imaging. Suppression of RAGE and CTGF expression in the diabetic myocardium appears to contribute to the antifibrotic effect of rosiglitazone. These results support the potential of PPAR-gamma agonists as antifibrotic agents in diabetic cardiomyopathy.

Development of Receptor for Advanced Glycation End Products–Directed Imaging of Atherosclerotic Plaque in a Murine Model of Spontaneous Atherosclerosis

The receptor for advanced glycation end products (RAGE) is implicated in the development and progression of atherosclerosis. We tested the hypothesis that (99m)Tc-labeled anti-RAGE F(ab')(2) can be used as a noninvasive tool to image atherosclerotic lesions in apolipoprotein E-deficient (apoE(-/-)) mice. A sequence in the V-type Ig extracellular domain of RAGE was used to develop a peptide injected into rabbits; serum was retrieved, IgG prepared and affinity-purified, and pepsin-digested into F(ab')(2). Thirteen 6-week apoE(-/-) mice were fed a Western diet. At 20 weeks, 6 were injected with 15.2+/-1.9 MBq (350 to 411 microCi) (99m)Tc-labeled anti-RAGE F(ab')(2), 6 were injected with (99m)Tc-labeled control nonspecific IgG F(ab')(2), and 1 was injected with dual-labeled (99m)Tc and rhodamine anti-RAGE F(ab')(2). Four 20-week C57BL/6 mice were injected with (99m)Tc-labeled anti-RAGE F(ab')(2). All mice were imaged on a high resolution mini-gamma camera 4 hours after injection and euthanized. The aortic tree was dissected and photographed, and the proximal aorta was sectioned for staining after gamma scintillation counting. All 6 apoE(-/-) mice injected with (99m)Tc-labeled anti-RAGE F(ab')(2) fragments showed focal tracer uptake in the proximal aorta (mean %ID/g, 1.98%). Disease and antibody controls showed no focal tracer uptake in the thorax (%ID/g, <1.0%). Histological sections of the proximal aorta showed American Heart Association class III lesions with lipid laden macrophages, smooth muscle cells, and positive staining for RAGE. On immunofluorescence, RAGE colocalized with macrophages. These data show the feasibility of noninvasively imaging RAGE in atherosclerotic lesions in a murine model and confirm levels of RAGE expression sufficient to allow detection on in vivo imaging.

The expression of advanced glycation endproduct receptors in rpe cells associated with basal deposits in human maculas

Basal deposits within Bruch's membrane are associated with aging and age-related macular degeneration (AMD) although the factors causing their formation are incompletely understood. Advanced glycation endproducts (AGEs) accumulate in Bruch's membrane including basal deposits and drusen with aging. One mechanism by which AGEs alter a cell's phenotype is via AGE receptors. The purpose of this study was to immunolocalize and quantify the expression of AGE receptors by RPE cells associated with basal deposits or normal Bruch's membrane that were microdissected from human maculas. Postmortem eyes from 14 aged control donors and five donors with non-neovascular AMD were cryopreserved. RPE cells associated with normal Bruch's membrane or basal deposits were laser capture microdissected. The RNA was extracted and used for RT-qPCR to quantify the expression of RAGE, AGE R1, AGE R2, and AGE R3. Streptavidin alkaline phosphatase immunohistochemistry for these receptors was also performed and sections were bleached from 14 normal and nine AMD donors. RT-qPCR showed significant upregulation of RAGE, AGE R1, and AGE R3 in RPE cells overlying basal deposits compared to cells attached to morphologically normal Bruch's membrane. Immunohistochemical analysis for RAGE, AGER1, R2, and R3 showed diffuse, light staining of RPE cells and strong choriocapillaris staining in areas of normal Bruch's membrane. In areas of basal deposits, the RPE had more intense staining for RAGE and AGER1 compared to regions of normal Bruch's membrane. These results suggest that AGE receptors could influence the formation of basal deposits during aging and AMD.

Evidence for participation of rage (receptor for advanced glycation end products), soluble rage (sRAGE) and S100A12 proteins, in control of the inflammatory response of amniotic cavity during pregnancy

END PRODUCTS), SOLUBLE RAGE (SRAGE) AND S100A12 PROTEINS, IN CONTROL OF THE INFLAMMATORY RESPONSE OF AMNIOTIC CAVITY DURING PREGNANCY IRINA A. BUHIMSCHI, GUOMAO ZHAO, CHRISTIAN PETTKER, MERT BAHTIYAR, LISSA MAGLOIRE, CATALIN S. BUHIMSCHI, Yale University, Obstetrics, Gynecology, and Reprod. Sciences, New Haven, Connecticut OBJECTIVE: RAGE (NF-B activator) is a novel membrane cell-surface receptor with role in inflammation. S100A12 (proteomic biomarker of inflammation) is a ligand for RAGE. sRAGE competitively inhibits RAGE ligands. Studies were conducted to understand the relationships among RAGE, sRAGE and S100A12 in the amniotic fluid (AF) and fetal tissues of women with PTL in the presence or absence of intra-AF infection/inflammation (IAI/I). STUDY DESIGN: AF was retrieved by amniocentesis in 93 consecutive women stratified as follows: i) CAFC: positive AF culture, n=20, GA=27.1G0.7wks; ii) AFC: negative AF culture, n=30, GA=28.7G0.9 wks; iii) 2nd trim. control, n=15, GA=18.5G0.4wks; iv) 3rd trim. control, n=28, GA=36.7G0.4wks. sRAGE and IL-6 levels were measured by highly specific immunoassay. Each sample was subjected to mass spectrometry (SELDI) for detection of S100A12. Fetal membranes, cord and placenta were stained for RAGE and S100A12 protein. RESULTS: The S100A12 [10.4kDa] biomarker was present in 70%(14/20) of women withCAFC but only in 10%(3/30) of women with –AFC(p!0.001). Its presence correlated with AF levels of IL-6 (r=0.63, p!0.001) and AF WBC count (r=0.71, p!0.001). No control had the S100A12 SELDI biomarker peak. Levels of the inhibitor sRAGE were not influenced by presence or absence of IAI/I but increased directly with increasing GA (r=0.67, p!0.001) [Figure]. Staining for RAGE was present in all fetal membranes, and did not vary with IAI/I. Staining for S100A12 was selectively and markedly increased in the amnion and chorio-decidua of patients with IAI/I.

The Receptor for Advanced Glycation End Products (RAGE) Is Elevated in Women with Preeclampsia

A leading theory of the pathophysiology of preeclampsia is that oxidative stress induces vascular endothelial cell dysfunction. Advanced glycation end products (AGEs) form when aldose sugars react nonenzymatically with proteins under conditions of oxidative stress. AGEs are circulating molecules and can generate reactive oxygen species and vascular dysfunction (in diabetes and atherosclerosis) through an association with cell surface receptors (RAGE). RAGE is a multiligand receptor, expressed in vascular tissue, which is upregulated by its own ligands. Insulin resistance and obesity are risk factors for developing preeclampsia, as well as being conditions that would increase RAGE levels. Thus, we hypothesized that women with preeclampsia will have elevated levels of RAGE protein compared with normal pregnant women. Biopsies of nonlaboring myometrium as well as omentum were taken from normal pregnant and preeclamptic women. Nonpregnant samples were obtained at the time of hysterectomy. Tissue sections were immunostained with anti‐RAGE as well as anti‐α‐actin and anti‐von Willebrand factor (to identify blood vessels and intact endothelial cells). Staining intensity was qualitatively described as well as given an intensity score, with the identity of the section concealed. Nonpregnant myometrial and omental vessels showed very low to undetectable levels of RAGE staining. Pregnancy induced a significant increase in RAGE protein levels in both myometrium and omental vasculature. Blood vessels from women with preeclampsia consistently had intense staining for RAGE in both vessel beds. Thus, our data suggest that since RAGE activation can induce similar pathophysiologic changes to those observed in women with preeclampsia (including NFκB activation, increased TNFα and endothelin), elevated RAGE protein may be contributing to the vascular dysfunction in preeclampsia.

The receptor for advanced glycation end products (RAGE) is a central mediator of the interaction of AGE-beta2microglobulin with human mononuclear phagocytes via an oxidant-sensitive pathway. Implications for the pathogenesis of dialysis-related amyloidosis.

An important component of amyloid fibrils in dialysis-related amyloidosis is a form of beta2microglobulin modified with advanced glycation end products (AGEs) of the Maillard reaction, known as AGE-beta2M. We demonstrate here that the interaction of AGE-beta2M with mononuclear phagocytes (MPs), cells important in the pathogenesis of the inflammatory arthropathy of dialysis-related amyloidosis, is mediated by the receptor for AGEs, or RAGE. 125I-AGE-beta2M bound to immobilized RAGE or to MPs in a specific, dose-dependent manner (Kd approximately 53.5 and approximately 81.6 nM, respectively), a process inhibited in the presence of RAGE blockade. AGE-beta2M-mediated monocyte chemotaxis was prevented by excess sRAGE or anti-RAGE IgG. Induction of tumor necrosis factor-alpha (TNF) expression by MPs exposed to AGE-beta2M resulted from engagement of RAGE, as appearances of TNF transcripts and TNF antigen release into culture supernatants were prevented by addition of sRAGE, a process mediated, at least in part, by oxidant stress. AGE-beta2M reduced cytochrome c and the elaboration of TNF by MPs was inhibited by N-acetylcysteine. Consistent with these data, immunohistochemical studies of AGE-laden amyloid deposits of a long-term hemodialysis patient revealed positive staining for RAGE in the MPs infiltrating these lesions. These data indicate that RAGE is a central binding site for AGEs formed in vivo and suggest that AGE-beta2M-MP-RAGE interaction likely contributes to the initiation of an inflammatory response in amyloid deposits of long-term hemodialysis patients, a process which may ultimately lead to bone and joint destruction.