GPIHBP1 is responsible for the entry of lipoprotein lipase into capillaries

The lipolytic processing of triglyceride-rich lipoproteins by lipoprotein lipase (LPL) is the central event in plasma lipid metabolism, providing lipids for storage in adipose tissue and fuel for vital organs such as the heart. LPL is synthesized and secreted by myocytes and adipocytes, but then finds its way into the lumen of capillaries, where it hydrolyzes lipoprotein triglycerides. The mechanism by which LPL reaches the lumen of capillaries has remained an unresolved problem of plasma lipid metabolism. Here, we show that GPIHBP1 is responsible for the transport of LPL into capillaries. In Gpihbp1-deficient mice, LPL is mislocalized to the interstitial spaces surrounding myocytes and adipocytes. Also, we show that GPIHBP1 is located at the basolateral surface of capillary endothelial cells and actively transports LPL across endothelial cells. Our experiments define the function of GPIHBP1 in triglyceride metabolism and provide a mechanism for the transport of LPL into capillaries.

Optimization of L-malic acid production by Aspergillus flavus in a stirred fermentor

Effects of various nutritional and environmental factors on the accumulation of organic acids (mainly L-malic acid) by the filamentous fungus Aspergillus flavus were studied in a 16-L stirred fermentor. Improvement of the molar yield (moles acid produced per moles glucose consumed) of L-malic acid was obtained mainly by increasing the agitation rate (to 350 rpm) and the Fe(z+) ion concentration (to 12 mg/L) and by lowering the nitrogen (to 271 mg/L) and phosphate concentrations (to 1.5 mM) in the medium. These changes resulted in molar yields for L-malic acid and total C(4) acids (L-malic, succinic, and fumaric acids) of 128 and 155%, respectively. The high molar yields obtained (above 100%) are additional evidence for the operation of part of the reductive branch of the tricarboxylic acid cycle in L-malic acid accumulation by A. flavus. The fermentation conditions developed using the above mentioned factors and 9% CaCO(3) in the medium resulted in a high concentration (113 g/L L-malic acid from 120 g/L glucose utilized) and a high overall productivity (0.59 g/L h) of L-malic acid. These changes in acid accumulation coincide with increases in the activities of NAD(+)-malate dehydrogenase, fumarase, and citrate synthase.

Neuronatin: a new inflammation gene expressed on the aortic endothelium of diabetic mice

OBJECTIVE

Identification of arterial genes and pathways altered in obesity and diabetes.

RESEARCH DESIGN AND METHODS

Aortic gene expression profiles of obese and diabetic db/db, high-fat diet-fed C57BL/6J, and control mice were obtained using mouse Affymetrix arrays. Neuronatin (Nnat) was selected for further analysis. To determine the function of Nnat, a recombinant adenovirus (Ad-Nnat) was used to overexpress the Nnat gene in primary endothelial cells and in the mouse aorta in vivo.

RESULTS

Nnat, a gene of unknown vascular function, was upregulated in the aortas of db/db and high-fat diet-fed mice. Nnat gene expression was increased in db/db mouse aorta endothelial cells. Nnat protein was localized to aortic endothelium and was selectively increased in the endothelium of db/db mice. Infection of primary human aortic endothelial cells (HAECs) with Ad-Nnat increased expression of a panel of nuclear factor-kappaB (NF-kappaB)-regulated genes, including inflammatory cytokines, chemokines, and cell adhesion molecules. Infection of mouse carotid arteries in vivo with the Ad-Nnat increased expression of vascular cell adhesion molecule 1 protein. Nnat activation of NF-kappaB and inflammatory gene expression in HAECs was mediated through pathways distinct from tumor necrosis factor-alpha. Nnat expression stimulated p38, Jun NH(2)-terminal kinase, extracellular signal-related kinase, and AKT kinase phosphorylation. Phosphatidylinositol 3-kinase and p38 inhibitors prevented Nnat-mediated activation of NF-kappaB-induced gene expression.

CONCLUSIONS

Nnat expression is increased in endothelial cells of obese and diabetic mouse blood vessels. The effects of Nnat on inflammatory pathways in vitro and in vivo suggest a pathophysiological role of this new gene in diabetic vascular diseases.

Comparison of objective diagnostic tests in glaucoma: Heidelberg retinal tomography and multifocal visual evoked potentials

PURPOSE

To compare sensitivity and specificity of functional and structural changes in glaucoma using two objective tests: the multifocal visual evoked potential (m-VEP) and Heidelberg retinal tomography II (HRT).

PATIENTS AND METHODS

41 glaucoma patients and 25 normal individuals participated in the study. One eye per individual was included in the study. Individuals were evaluated with Humphrey visual field (HVF) perimetry, m-VEP, and HRT. Moorfield regression analysis findings of HRT were compared with presence of scotoma on m-VEP. Linear regression analysis of quantitative variables, such as HVF mean deviation (MD), m-VEP discriminant score (Accumap Severity Index) and, global HRT parameters was also performed.

RESULTS

m-VEP sensitivity and specificity were 93% and 96% respectively. HRT sensitivity and specificity were 79% and 92% respectively. The area under the receiver operating characteristic curve (ROC) for m-VEP was 0.96 and for HRT varied from 0.79 to 0.86 depending on the parameters used. Linear correlation between MD and Accumap Severity Index score was -77%, while that between HRT global parameters, Accumap Severity Index and MD were at best around 50%. Topographic comparison of the presence of scotoma on HVF and m-VEP in different areas of the visual field showed good agreement. Comparison of optic nerve head structural abnormality with corresponding areas of field defects on HVF and m-VEP showed poor to moderate agreement.

CONCLUSION

The objective test of optic nerve function (m-VEP) and structure (HRT) can detect glaucomatous damage, with limited correlation. The 2 functional tests, HVF and m-VEP correlate better with each other than with HRT. It remains important to look for both functional and structural changes in order to detect all glaucoma cases.

Novel Anti-inflammatory Role for Glycogen Synthase Kinase-3β in the Inhibition of Tumor Necrosis Factor-α- and Interleukin-1β-induced Inflammatory Gene Expression

Glycogen synthase kinase-3beta (GSK-3beta) is a serine/threonine kinase with a broad array of cellular targets, such as cytoskeletal proteins and transcription factors. Recent studies with GSK-3beta-null mice showed impaired NFkappaB-mediated survival responses. Because NFkappaB serves a dual role as a key regulator of cytokine-induced inflammatory gene expression and apoptosis, we investigated whether modulation of GSK-3beta expression affects cytokine-induced and NFkappaB-mediated inflammatory gene expression. We observed that tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) treatment of primary cultures of human microvascular cells reduced net endogenous active GSK-3beta protein levels while inducing inflammatory cytokine (IL-6 and monocyte chemoattractant protein-1 (MCP-1)) expression. Interestingly, inhibition of GSK-3beta by antisense oligonucleotides or pharmacological agent (10 mm lithium) potentiated TNF-induced expression of IL-6 and MCP-1 by 2-6-fold suggesting that inhibition of GSK-3beta under inflammatory conditions (exposure to TNF-alpha and IL-1beta) may contribute to enhanced cytokine expression. Overexpression of GSK-3beta in endothelial cells, in contrast, significantly inhibited (by 70%, p < 0.01) both TNF-alpha and IL-1beta-induced expression of IL-6, MCP-1, and vascular cell adhesion molecule-1. Using adenoviruses in lipopolysaccharide-stimulated mice, overexpression of GSK-3beta significantly decreased TNF-alpha expression in lung and heart tissues (38 and 15%, respectively), further confirming the anti-inflammatory role of GSK-3beta. Overexpression of GSK-3beta did not affect the TNF-alpha-induced nuclear translocation of NFkappaB but reduced the nuclear half-life of TNF-alpha-induced NFkappaB considerably (by as much as 9 h) and enhanced phosphorylation (by as much as 33%). Interestingly, neither endothelial cell survival nor NFkappaB-mediated expression of anti-apoptotic genes was affected by GSK-3beta overexpression. We conclude that GSK-3beta selectively regulates NFkappaB-mediated inflammatory gene expression by controlling the flow of NFkappaB activity between transcription of inflammatory and survival genes.

Topography of the frequency doubling perimetry visual field compared with that of short wavelength and achromatic automated perimetry visual fields

BACKGROUND

Traquair described the topography of visual field sensitivity as a "hill" or "island" of vision. Achromatic automated perimetry (AAP) demonstrates this shape of the visual field in photopic conditions. Techniques claimed to target the magnocellular pathway (frequency doubling perimetry, FDP) and those using a stimulus targeting the koniocellular pathway (short wavelength (or blue on yellow) automated perimetry, SWAP), might produce one that is different. The authors compared the visual field topography from FDP with those of SWAP and AAP, to investigate whether there were significant differences in their shape.

METHOD

A sample of 51 patients with previously confirmed normal perimetry were recruited; either low risk glaucoma suspects or normal controls. AAP, SWAP, and FDP perimetry was performed in random order on the same day. The topography of each field was analysed to determine its average shape and to compare results in the same individuals.

RESULTS

The topography of the visual field produced by each perimeter differed significantly. While all three had maximal sensitivity centrally, over the 24 degrees from the centre to the periphery, mean sensitivities decreased by 4.9 decibels (dB) for AAP and 7.3 dB for SWAP, while FDP sensitivities by just 1.8 dB over 20 degrees (the extent of the FDP field). FDP mean sensitivities decreased by approximately 0.3 dB with every 10 year increase in age, compared with 1 dB for AAP and 2 dB for SWAP.

CONCLUSION

While the topography of the SWAP (koniocellular) field is steeper than corresponding AAP fields, that of the FDP (magnocellular) visual field was considerably flatter. The difference in this shape may reflect retinotopic or cortical mechanisms, which are specific to the magnocellular pathways.

Overexpression of 15-lipoxygenase in the vascular endothelium is associated with increased thymic apoptosis in LDL receptor-deficient mice

BACKGROUND

15-Lipoxygenase (15-LO) is a nonheme iron-containing enzyme that catalyzes the peroxidation of fatty acids. Herein, we studied the effect of 15-LO overexpression in the vascular endothelium on thymocyte apoptosis by evaluating thymuses from low-density lipoprotein receptor-deficient (LDL-RD) mice and LDL-RD/15-LO mice. Thymuses were evaluated by immunohistochemistry and by TUNEL whereas in vitro studies were carried out by employing freshly isolated thymocytes from the respective mice and evaluation of apoptosis by propidium iodide and annexin V cytometry.

METHODS AND RESULTS

The apoptotic index in LDL-RD/15-LO mice was significantly higher than in the LDL-RD mice. In the thymic medulla the difference was smaller, although still significant. Freshly isolated thymus cells from LDL-RD/15-LO mice exhibited a higher rate of spontaneous cell death than controls. Incubation of thymus cells in the presence of the cell-permeable caspase-3 inhibitor DEVD-CMK resulted in a decrease in the frequency of apoptotic cells in LDL-RD/15-LO thymocytes, whereas no effect was evident in control thymocytes. The antioxidant N-acetylcysteine causes the increase in apoptosis in both groups.

CONCLUSION

LDL-RD/15-LO mice exhibit increased thymocyte apoptosis both in vivo and in vitro. These findings may suggest a role for 15-LO in the natural selection of thymocytes.

ErbB2 is a tumor associated antigen and a suitable therapeutic target in Wilms tumor

PURPOSE

The modern multimodality therapeutic approach to Wilms tumor (WT), combining surgery with radiotherapy and chemotherapy results in high cure rates even for high stage disease. However, the combination of radiotherapy and chemotherapy is associated with severe early and late complications such as neutropenic sepsis, growth retardation and secondary malignancies. Therefore, novel therapeutic strategies, which would decrease the treatment burden, are required. We studied the expression of erbB2 growth factor receptor in WT cells as well as its role as a tumor therapeutic target in an in vivo xenograft model of Wilms tumor.

MATERIALS AND METHODS

Paraffin embedded pathological samples from 14 different WT cases as well as xenografts derived thereof were immunostained with anti-erbB2 monoclonal antibody. The immunostaining was graded in comparison to a known positive control (breast cancer) and was scored by the intensity of staining (0 to +3) multiplied by the percentage of cells expressing the antigen. The expression of erbB2 in the human WT xenograft was verified also by fluorescence activated cell sorter analysis. In addition, nude mice bearing established subcutaneous human WT xenografts were treated with either 3 intraperitoneal injections of N29 anti-erbB2 monoclonal antibody or irrelevant antibody.

RESULTS

All of the authentic human pathological samples, except 1 anaplastic WT as well the WT xenografts (at different stages), expressed erbB2. Expression was also observed in WT metastasis and in tumors which out grew chemotherapy. Systemic administration of anti-erbB2 monoclonal antibody inhibited and even prevented the growth of WT xenograft in vivo.

CONCLUSIONS

ErbB2 is a tumor associated antigen in WT. Being expressed in almost all tumor stages, our in vivo model suggests that erbB2 may serve as a WT therapeutic target. Further work is needed to establish the role of erbB2 in the disease and its potential use in decreasing current treatment burden.

Common ancestral origin of pemphigus vulgaris in Jews and Spaniards: a study using microsatellite markers

Pemphigus is a group of autoimmune blistering diseases of the skin and mucous membranes. The association of pemphigus with human leukocyte antigen (HLA) is widely accepted. It was described in many ethnic groups and in most countries of the world. Studies showed that the associated HLA haplotype in Jewish pemphigus vulgaris (PV) patients is HLA-B38, DRB1*0402, and DQB1*0302; or HLA-B35, DRB1*0402, and DQB1*0302. Similar associations with class II genes were found in Spanish non-Jewish PV patients. As Jews lived in Spain for hundreds of years and many converted to Christianity, the presence of the same HLA haplotype in the Jewish and Spanish PV suggests that they may share the same founder. Microsatellite markers which span the entire major histocompatibility complex (MHC) locus were used as genetic probes. They were utilized to dissect the MHC region in the search for possible common haplotypes, besides HLA, which may provide an answer to this question. It was found that in both cohorts, in addition to HLA class II genes, there are probably genes in the class I region which are associated with PV. Alleles belonging to the associated markers were used to construct haplotypes and to estimate genetic distances. The distance between the two PV cohorts is relatively short, but the distance between the Jewish patients and the Jewish controls is greater compared to the distance between Spanish patients and Spanish controls. In both PV populations, the same microsatellite haplotypes in addition to a common class II haplotype were found, suggesting that both patient populations originated from the same genetic stock and, therefore, share the same ancestral disease gene.

The loss of calretinin expression indicates aganglionosis in Hirschsprung's disease

BACKGROUND

Hirschsprung's disease (HD) is a congenital disorder characterised by the absence of ganglion cells in the large bowel, leading to functional obstruction and colonic dilatation proximal to the affected segment. A subclass of nerve cell bodies in both submucosa and myenteric ganglia of the human gastrointestinal tract were found to show immunopositivity for calretinin, a calcium binding protein, which plays an important role in the organisation and functioning of the central nervous system.

AIM

To investigate calretinin immunostaining in ganglionic and aganglionic HD colon specimens, and compare it with staining for S100, neurone specific enolase, and c-kit.

METHODS

Ten large bowel, full thickness specimens from patients with classic rectosigmoid HD were selected from the pathology repository. In total, 54 paraffin wax blocks-24 from the ganglionic zone, 17 from the aganglionic zone, and 13 from the transitional zone-were processed.

RESULTS

Calretinin was not expressed in aganglionic segments of HD and associated nerve fibres, whereas in ganglionic HD segments and in normal colon both ganglion cells and nerve fibres were immunopositive. In addition, c-kit showed an altered distribution in the interstitial cells of Cajal. The transitional zone showed a broad spectrum of histomorphological and immunohistochemical patterns of both calretinin and c-kit expression.

CONCLUSION

The absence of calretinin expression may serve as a diagnostic aid in identifying aganglionic segments in HD.

Analyses of p53 expression pattern and BRCA mutations in patients with double primary breast and ovarian cancer

OBJECTIVE

To analyze the somatic pattern of p53 expression and BRCA germline mutation status in Israeli patients with both ovarian (OvCa) and breast cancer (BrCa).

METHODS

The study group comprised 43 Israeli patients with OvCa, all of whom had previous primary BrCa. p53 immunohistochemistry (IHC) on all available archival tissues and genotyping for the three predominant Jewish germline BRCA1-2 mutations were carried out. Samples from 64 patients with solitary OvCa and 61 with solitary BrCa were similarly analyzed as controls.

RESULTS

p53 expression pattern and the immunopositivity rate were similar in the ovarian and breast tumors within the study group and in the two control groups: positive p53 staining was detected in 68% of ovarian tumors in the study group compared with 71.9% in the controls, and in 19.4% of the BrCa tissues versus 21.3% in the controls. Within the study group, advanced stage OvCa had a higher rate of p53 expression (84%) compared to early stage disease (38.5%) (P = 0.006). This difference was not apparent in the solitary OvCa control group. OvCa in BRCA1-2 mutation carriers from the study group were more likely to display positive p53 staining (79%), especially in tumors diagnosed before the age of 60 (90%) compared with the OvCa of noncarriers (60%), but this difference was statistically insignificant. The p53 expression rate in BrCa samples from the study group was not associated with BRCA1-2 mutation status.

CONCLUSIONS

Positive p53 expression, detected by IHC, in OvCa patients with previous primary BrCa is significantly higher in advanced stage disease in BRCA1-2 mutation carriers. There is a higher positive p53 expression somatically in OvCa in BRCA1-2 carriers in whom OvCa was diagnosed before the age of 60 years, although this trend is not statistically significant. These observations suggest that somatic p53 inactivation may be an important event in ovarian tumorigenesis in this subset of patients.

Analyses of p53 expression pattern and BRCA mutations in patients with double primary breast and ovarian cancer

Objective

To analyze the somatic pattern of p53 expression and BRCA germline mutation status in Israeli patients with both ovarian (OvCa) and breast cancer (BrCa).

Methods

The study group comprised 43 Israeli patients with OvCa, all of whom had previous primary BrCa. p53 immunohistochemistry (IHC) on all available archival tissues and genotyping for the three predominant Jewish germline BRCA1–2 mutations were carried out. Samples from 64 patients with solitary OvCa and 61 with solitary BrCa were similarly analyzed as controls.

Results

p53 expression pattern and the immunopositivity rate were similar in the ovarian and breast tumors within the study group and in the two control groups: positive p53 staining was detected in 68% of ovarian tumors in the study group compared with 71.9% in the controls, and in 19.4% of the BrCa tissues versus 21.3% in the controls. Within the study group, advanced stage OvCa had a higher rate of p53 expression (84%) compared to early stage disease (38.5%) (P = 0.006). This difference was not apparent in the solitary OvCa control group. OvCa in BRCA1–2 mutation carriers from the study group were more likely to display positive p53 staining (79%), especially in tumors diagnosed before the age of 60 (90%) compared with the OvCa of noncarriers (60%), but this difference was statistically insignificant. The p53 expression rate in BrCa samples from the study group was not associated with BRCA1–2 mutation status.

Conclusions

Positive p53 expression, detected by IHC, in OvCa patients with previous primary BrCa is significantly higher in advanced stage disease in BRCA1–2 mutation carriers. There is a higher positive p53 expression somatically in OvCa in BRCA1–2 carriers in whom OvCa was diagnosed before the age of 60 years, although this trend is not statistically significant. These observations suggest that somatic p53 inactivation may be an important event in ovarian tumorigenesis in this subset of patients.

Libman–Sacks endocarditis associated with antiphospholipid syndrome and infection

INTRODUCTION

Antiphospholipid syndrome (APS) is a systemic autoimmune disease, associated not only with a hypercoagulable state and recurrent fetal loss but with many diverse clinical manifestations including heart involvement, neurological manifestations, as well as skin, kidney and hematologic abnormalities. Cardiac manifestations include coronary by-pass graft and angioplasty occlusions, cardiomyopathy, cyanotic congenital heart disease, intracardiac thrombus and complications of cardiovascular surgery. The valvular heart disease was defined as Libman-Sacks nonbacterial endocarditis. Previously, we have shown a linear subendothelial deposition of anti-cardiolipin/beta2 glycoprotein I (beta2GPI) antibodies in the valve specimens derived from APS patients. The involvement of complement C3c in the pathogenesis was documented. We assessed the beta2GPI-related target epitope recognized by the anti-beta2GPI Abs on the valves.

MATERIALS AND METHODS

In order to find the beta2GPI-related target epitopes recognized by the anti-beta2GPI antibodies on the valves, we used beta2GPI-related synthetic peptides. The presence of anti-beta2GPI Abs on the studied valves was detected by anti-idiotypic antibody, followed by immunoperoxidase analysis. Biotin attached to the N-terminal of beta2GPI-related synthetic peptides and control peptide were used to identify the epitope addressed by the anti-beta2GPI Abs deposited on the patient's valve. The binding was probed by streptavidin-peroxidase and appropriate substrate. The specificity was confirmed by competition assays with control peptide and anti-idiotypic antibody.

RESULTS

Among the beta2GPI-related synthetic peptides, two peptides were found in previous studies to mimic common pathogens either bacteriae or viruses, which raised a possible infectious origin for APS. One of these peptides, TLRVYK, is a specific target for anti-beta2GPI Abs deposited on the APS valves. This synthetic peptide was able to displace the anti-anti-beta2GPI anti-idiotypic Abs for binding the anti-beta2GPI Abs on the valve by a competition assay.

CONCLUSION

We point to the possibility that Libman-Sacks nonbacterial endocarditis may have an infectious origin.

Relation of preexisting anti-beta2GPI antibodies to infarct size in a rat model

BACKGROUND

Anti-beta2-glycoprotein I (beta2GPI) antibodies (a subpopulation of antiphospholipid (aPL) antibodies) are associated with a procoagulant state in humans and with enhanced atherosclerosis in experimental animal models. Moreover, the presence of high titers of aPL antibodies in relatively young patients is associated with higher incidence of subsequent myocardial infarction. Herein, we evaluated the role of preexisting high levels of aPL antibodies in determining the size of the infarct induced by permanent ligation of the left anterior descending artery (LAD) in a rat model.

METHODS AND RESULTS

A total of 11 Wistar rats were immunized and boosted with 10 microg of the phospholipid binding protein -beta2GPI (a method commonly applied for induction of aPL antibodies). Rats in the control group (n=9) were immunized and boosted with a Freund's adjuvant. Upon development of high anti-beta2GPI antibodies levels, myocardial infarction was induced by ligation of the LAD coronary artery. Rats were sacrificed 7 days later, their lymph nodes were collected for evaluation of cellular immunity to beta2GPI and their hearts were removed for assessment of infarct size and for immunohistochemical stains for iNOS and TGF-beta. beta2GPI-immunized rats exhibited high levels of aPL antibodies (mean optical density of 1.3+/-0.3) as compared with the control group (mean optical density of 0.12+/-0.03; P<.0001). Cellular immunity to beta2GPI was also pronounced as evident by an increased thymidine uptake and by increased interferon gamma secretion by the lymph node cells from beta2GPI-immunized rats. Myocardial infarct size has shown a tendency to be increased in rats induced to develop anti-beta2GPI antibodies (mean size 23+/-9%) as compared with controls (17+/-12%; P<.23). iNOS positive cells in the infarct area of beta2GPI-immunized rats were significantly increased in comparison to the control group (P<.01). Similarly, TGF-beta cell expression was significantly increased in the infarct area of the immunized rats in comparison to the control group (22.6+/-5.1 and 7+/-2.1 per 100 mononuclear inflammatory cells, respectively; P=.01).

CONCLUSION

The presence of high levels of aPL antibodies is associated with higher expression of iNOS and TGF-beta and may contribute to myocardial damage.