Heparan sulfates, the carbohydrate chains of heparan sulfate proteoglycans, play an important role in basement membrane organization and endothelial barrier function. We explored whether endothelial cells secrete a heparan sulfate degrading heparanase under inflammatory conditions and what pathways were responsible for heparanase expression. Heparanase mRNA and protein by Western blot were induced when cultured endothelial cells were treated with cytokines, oxidized low-density lipoprotein (LDL) or fatty acids. Heparanase protein in the cell media was induced 2-10-fold when cells were treated with tumor necrosis factor alpha (TNFalpha) or interleukin 1beta (IL-1beta). Vascular endothelial growth factor (VEGF), in contrast, decreased heparanase secretion. Inhibitors to nuclear factor-kappaB (NFkappaB), PI3-kinase, MAP kinase, or c-jun kinase (JNK) did not affect TNFalpha-induced heparanase secretion. Interestingly, inhibition of caspase-8 completely abolished heparanase secretion induced by TNFalpha. Fatty acids also induced heparanase, and this required an Sp1 site in the heparanase promoter. Immunohistochemical analyses of cross sections of aorta showed intense staining for heparanase in the endothelium of apoE-null mice but not wild-type mice. Thus, heparanase is an inducible inflammatory gene product that may play an important role in vascular biology.

Lipoprotein lipase (LPL), the rate-limiting enzyme for hydrolysis of plasma lipoprotein triglycerides, is a normal constituent of the arterial wall. We explored whether LPL affects (a) lipoprotein transport across bovine aortic endothelial cells or (b) lipoprotein binding to subendothelial cell matrix (retention). When bovine milk LPL was added to endothelial cell monolayers before addition of "2'I-labeled LDL, LDL transport across the monolayers was unchanged; but, at all concentrations of LDL tested (1-100 jig), LDL retention by the monolayers increased more than fourfold. '251-labeled LDL binding to extracellular matrix increased when LPL was added directly to the matrix or was added to the basolateral side ofthe endothelial cell monolayers. Increased LDL binding required the presence of LPL and was not associated with LDL aggregation. LPL also increased VLDL, but not HDL, retention. Monoclonal anti-LPL IgG decreased both VLDL and LDL retention in the presence of LPL. Lipoprotein transport across the monolayers increased during hydrolysis of VLDL triglyceride (TG). In the presence of LPL and VLDL, VLDL transport across the monolayers increased 18% and LDL transport increased 37%. High molar concentrations of oleic acid to bovine serum albumin (3:1) in the medium increased VLDL transport 30%.LDL transport increased 42% when oleic acid was added to the media. Therefore, LPL primarily increased retention of LDL and VLDL. A less remarkable increase in lipoprotein transport was found during hydrolysis of TG-containing lipoproteins. We hypothesize that LPL-mediated VLDL and LDL retention within the arterial wall potentiates conversion of these lipoproteins to more atherogenic forms. (J. Clin. Invest. 1992.89:373-380.)

Purpose of ReviewNutritional rickets and osteomalacia are common in dark-skinned and migrant populations. Their global incidence is rising due to changing population demographics, failing prevention policies and missing implementation strategies. The calcium deprivation spectrum has hypocalcaemic (seizures, tetany and dilated cardiomyopathy) and late hypophosphataemic (rickets, osteomalacia and muscle weakness) complications. This article reviews sustainable prevention strategies and identifies areas for future research.Recent FindingsThe global rickets consensus recognises the equal contribution of vitamin D and dietary calcium in the causation of calcium deprivation and provides a three stage categorisation for sufficiency, insufficiency and deficiency. For rickets prevention, 400 IU daily is recommended for all infants from birth and 600 IU in pregnancy, alongside monitoring in antenatal and child health surveillance programmes.SummaryHigh-risk populations require lifelong supplementation and food fortification with vitamin D or calcium. Future research should identify the true prevalence of rickets and osteomalacia, their role in bone fragility and infant mortality, and best screening and public health prevention tools.

BackgroundNutritional rickets is a growing global public health concern despite existing prevention programmes and health policies. We aimed to compare infant and childhood vitamin D supplementation policies, implementation strategies and practices across Europe and explore factors influencing adherence.MethodsEuropean Society for Paediatric Endocrinology Bone and Growth Plate Working Group members and other specialists completed a questionnaire on country-specific vitamin D supplementation policy and child health care programmes, socioeconomic factors, policy implementation strategies and adherence. Factors influencing adherence were assessed using Kendall’s tau-b correlation coefficient.ResultsResponses were received from 29 of 30 European countries (97%). Ninety-six per cent had national policies for infant vitamin D supplementation. Supplements are commenced on day 1–5 in 48% (14/29) of countries, day 6–21 in 48% (14/29); only the UK (1/29) starts supplements at 6 months. Duration of supplementation varied widely (6 months to lifelong in at-risk populations). Good (≥80% of infants), moderate (50–79%) and low adherence (<50%) to supplements was reported by 59% (17/29), 31% (9/29) and 10% (3/29) of countries, respectively. UK reported lowest adherence (5–20%). Factors significantly associated with good adherence were universal supplementation independent of feeding mode (P = 0.007), providing information at neonatal unit (NNU) discharge (P = 0.02), financial family support (P = 0.005); monitoring adherence at surveillance visits (P = 0.001) and the total number of factors adopted (P < 0.001).ConclusionsGood adherence to supplementation is a multi-task operation that works best when parents are informed at birth, all babies are supplemented, and adherence monitoring is incorporated into child health surveillance visits. Implementation strategies matter for delivering efficient prevention policies.

These suppression-release effects of high-dose denosumab on bone remodeling raise questions about safety of fixed dosing and treatment duration. In young people, weight-adjusted dosing and safety monitoring during and after antiresorptive therapy is required.

To explore the therapeutic efficacy and potential mechanisms of action of a new class of antiatherosclerotic drugs, AGI-1067 [mono[4-[[1-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]thio]-1-methylethyl]thio]-2,6-bis(1,1-dimethylethyl)phenyl] ester] (butanedioc acid) was tested in several animal models of atherosclerosis. AGI-1067, a novel phenolic antioxidant, was well tolerated in a 1-year study in hypercholesterolemic cynomolgus monkeys. It lowered low-density lipoprotein cholesterol (LDLc) by 41 and 90% at oral doses of 50 and 150 mg/kg, respectively and increased high-density lipoprotein cholesterol (HDLc) by 107% at the higher dose. In contrast, another phenolic antioxidant, probucol, had a modest LDLc-lowering effect (15% at 250 mg/kg) while decreasing HDLc (37% at 150 mg/kg). Histopathology of the aortas and coronary arteries revealed no atherosclerosis in the AGI-1067 (150 mg/kg) group and minimal-to-moderate atherosclerosis in the vehicle and probucol (150 mg/kg) groups. AGI-1067 also inhibited atherosclerosis in LDL receptor-deficient (LDLr Ϫ/Ϫ) mice and apolipoprotein E-deficient (ApoE Ϫ/Ϫ) mice even in the absence of a lipid-lowering effect. In LDLr Ϫ/Ϫ mice, AGI-1067 reduced aortic atherosclerosis by 49%. In ApoE Ϫ/Ϫ mice, AGI-1067 reduced atherosclerosis by 25, 41, and 49% in the arch, thoracic, and abdominal regions of the aorta. AGI-1067 also reduced vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) mRNA levels in lungs of lipopolysaccharide-stimulated mice. At the cellular level, AGI-1067 inhibited tumor necrosis factor-␣-inducible expression of VCAM-1, MCP-1, and E-selectin in human aortic endothelial cells (IC 50 values ϭ 6, 10, and 25 M, respectively). These data show that AGI-1067 can inhibit atherosclerosis not only via its lipid-lowering effects but also by having direct anti-inflammatory effects on the vessel wall and suggest that it may be a novel therapeutic agent for coronary artery disease.

OBJECTIVE-Lipoic acid synthase (LASY) is the enzyme that is involved in the endogenous synthesis of lipoic acid, a potent mitochondrial antioxidant. The aim of this study was to study the role of LASY in type 2 diabetes.RESEARCH DESIGN AND METHODS-We studied expression of LASY in animal models of type 2 diabetes. We also looked at regulation of LASY in vitro under conditions that exist in diabetes. Additionally, we looked at effects of LASY knockdown on cellular antioxidant status, inflammation, mitochondrial function, and insulin-stimulated glucose uptake.RESULTS-LASY expression is significantly reduced in tissues from animal models of diabetes and obesity compared with ageand sex-matched controls. In vitro, LASY mRNA levels were decreased by the proinflammatory cytokine tumor necrosis factor (TNF)-␣ and high glucose. Downregulation of the LASY gene by RNA interference (RNAi) reduced endogenous levels of lipoic acid, and the activities of critical components of the antioxidant defense network, increasing oxidative stress. Treatment with exogenous lipoic acid compensated for some of these defects. RNAi-mediated downregulation of LASY induced a significant loss of mitochondrial membrane potential and decreased insulinstimulated glucose uptake in skeletal muscle cells. In endothelial cells, downregulation of LASY aggravated the inflammatory response that manifested as an increase in both basal and TNF-␣-induced expression of the proinflammatory cytokine, monocyte chemoattractant protein-1 (MCP-1). Overexpression of the LASY gene ameliorated the inflammatory response.CONCLUSIONS-Deficiency of LASY results in an overall disturbance in the antioxidant defense network, leading to increased inflammation, insulin resistance, and mitochondrial dysfunction. Diabetes 58:600-608, 2009 T ype 2 diabetes is the most prevalent chronic metabolic disease in the world. In the past decade, considerable evidence has accumulated implicating oxidative stress as a key factor that accelerates the onset and progression of type 2 diabetes. Chronic oxidative stress causes inflammation and mitochondrial dysfunction and culminates in insulin resistance, which ultimately progresses to diabetes. Oxidative stress also promotes cellular dysfunction and damage, leading to the development of secondary complications of diabetes. The underlying cause of redox imbalance is a deficiency in the endogenous antioxidant network. This deficiency would result in an inability to combat excessive amounts of reactive oxygen species (ROS) and tip the balance in favor of oxidative stress.Redox balance is maintained by an antioxidant defense network within mitochondria, consisting of stress-responsive enzymes such as superoxide dismutase (SOD), catalase and reduced glutathione (GSH), and antioxidants. The antioxidant defense network is activated in response to excessive production of ROS in the mitochondria, thereby neutralizing the ROS before they inflict damage on cellular molecules. Lipoic acid is a potent mitochondrial antioxidant that plays a central role in...

Apolipoprotein E (apoE) is known to inhibit cell proliferation; however, the mechanism of this inhibition is not clear. We recently showed that apoE stimulates endothelial production of heparan sulfate (HS) enriched in heparin-like sequences. Because heparin and HS are potent inhibitors of smooth muscle cell (SMC) proliferation, in this study we determined apoE effects on SMC HS production and cell growth. In confluent SMCs, apoE (10 g/ml) increased 35 SO 4 incorporation into PG in media by 25-30%. The increase in the medium was exclusively due to an increase in HSPGs (2.2-fold), and apoE did not alter chondroitin and dermatan sulfate proteoglycans. In proliferating SMCs, apoE inhibited [ 3 H]thymidine incorporation into DNA by 50%; however, despite decreasing cell number, apoE increased the ratio of 35 SO 4 to [ 3 H]thymidine from 2 to 3.6, suggesting increased HS per cell. Purified HSPGs from apoE-stimulated cells inhibited cell proliferation in the absence of apoE. ApoE did not inhibit proliferation of endothelial cells, which are resistant to heparin inhibition. Analysis of the conditioned medium from apoE-stimulated cells revealed that the HSPG increase was in perlecan and that apoE also stimulated perlecan mRNA expression by >2-fold. The ability of apoE isoforms to inhibit cell proliferation correlated with their ability to stimulate perlecan expression. An anti-perlecan antibody completely abrogated the antiproliferative effect of apoE. Thus, these data show that perlecan is a potent inhibitor of SMC proliferation and is required to mediate the antiproliferative effect of apoE. Because other growth modulators also regulate perlecan expression, this may be a key pathway in the regulation of SMC growth.