Laura Schreier

University of Buenos Aires, Buenos Aires, Buenos Aires F.D., Argentina

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Publications (97)263.11 Total impact

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    ABSTRACT: Background Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9, have been identified in atherosclerotic plaques and have been directly associated with plaque remodeling and vulnerability. Cardiovascular disease is related to insulin-resistance (IR) and obesity, characterized by changes in plasma levels of inflammatory markers, such as adiponectin and C reactive protein (CRP). Our aim was to evaluate the impact of both proteins on MMP-2 and MMP-9 behavior in individuals with IR.Materials and methodsPlasma MMP-2 and MMP-9 activity, adiponectin and hs-CRP concentration and lipoprotein profile were determined in 52 patients with Metabolic Syndrome (MS) and 27 controls.ResultsPatients with MS presented significantly higher MMP-2 activity than controls: 0.95 ± 0.12 vs 0.77 ± 0.15 relative units (RU) (p<0.001), while MMP-9 activity was no detectable MMP-2 activity decreased across quartiles of adiponectin, being significantly reduced in individuals with the highest levels of adiponectin in compared with the lowest levels (0.75±0.17 vs 0.93±0.09 RU, p<0.005). This difference persisted significant after adjusting by obesity markers. MMP-2 activity was significantly increased in individuals with the highest levels (G3) compared with those with the lowest levels (G1) of hs-CRP (0.94±0.12 vs 0.86±0.12, p=0.041)Conclusion In this study we observed that adiponectin levels predicted MMP-2 plasma activity independently of obesity. This finding suggests that the inflammatory process, associated with the highest CVD risk, would be involved in MMPs vascular production.This article is protected by copyright. All rights reserved.
    European Journal of Clinical Investigation 08/2014; · 3.37 Impact Factor
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    ABSTRACT: Abstract Background: Type 2 diabetes (T2DM) and chronic renal disease constitute important risk factors of atherosclerotic cardiovascular disease, associated with lipid abnormalities, and proinflammatory states. Advances in renal replacement therapy such as hemodialysis (HD) have not reduced morbi-mortality. It has not been elucidated if the concomitant presence of T2DM or metabolic syndrome with end-stage renal disease further impairs the atherogenic profiles. Methods: We studied 122 HD patients, among which 44 presented with T2DM (HD-T2DM) and 30 with metabolic syndrome (HD-MS); 48 had neither T2DM nor metabolic syndrome (HD-C). Lipoprotein profile, including atherogenic remnant lipoproteins (RLP), and inflammation markers-high sensitivity C-reactive protein (hsCRP), adiponectin, and interleukin-6 (IL-6)-were measured. Results: In all HD patients, triglycerides, free fatty acids, and RLP showed no differences between HD groups, whereas high-density lipoprotein cholesterol (HDL-C) was decreased, particularly in HD-T2DM and HD-MS, with respect to HD-C (P<0.01). Regarding inflammatory parameters, both IL-6 and hsCRP were found to be similar between HD groups. Adiponectin paradoxically shows higher values in relation to those expected for insulin resistance situations showing no differences between HD groups. Conclusions: The presence of T2DM or metabolic syndrome did not worsen atherogenic lipoprotein levels, but did reduce HDL-C. Neither was the proinflammatory profile further altered in HD patients in the presence of insulin resistance conditions.
    Metabolic syndrome and related disorders 03/2014; · 1.92 Impact Factor
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    ABSTRACT: Abstract Matrix metalloproteinases (MMPs) play an important role during physiological tissue remodeling in embryonic development and angiogenesis, as well as in pathophysiological conditions such as obesity and development and vulnerability of atherosclerotic plaque. Moreover, MMP circulating levels have emerged as potential biomarkers of cardiovascular disease. MMP expression and activity are regulated by different factors such as insulin resistance and obesity. Expanded fat tissue has been demonstrated to be an active organ, where MMPs also exert a role in adipogenesis, angiogenesis, and proliferation of extracellular matrix (ECM). However, the lack of association between adipose tissue and plasma levels of some MMPs, specifically MMP-2 and MMP-9, suggests that this tissue is not a major contributor to circulating gelatinases. MMPs are also co-expressed or co-repressed in response to inflammatory adipocytokines, like adiponectin and leptin. Adiponectin may also play a protective role in plaque rupture through selectively increasing the tissue inhibitor of metalloproteinase (TIMP) expression. Leptin induces the expression of MMP-2 activators as well as the expression of MMP-2, MMP-9, and TIMP-1 in different human cells. Furthermore, sex hormones also participate in MMP regulation. In postmenopausal women, hormone replacement therapy produces an increase in MMP activity, leading to a breakdown in ECM homeostasis and accelerated progression of vascular pathologies. Besides, in men, an inverse relationship between testosterone levels and MMP-2 activity has been described. It is still necessary to go forward in the study of MMPs in different metabolic situations to corroborate their role as vulnerable plaque biomarkers.
    Hormone molecular biology and clinical investigation 02/2014; 17(2):79-87.
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    ABSTRACT: To assess the phospholipase activity of endothelial (EL) and hepatic lipase (HL) in postheparin plasma of subjects with metabolic syndrome (MS)/obesity and their relationship with atherogenic and antiatherogenic lipoproteins. Additionally, to evaluate lipoprotein lipase (LPL) and HL activity as triglyceride (TG)-hydrolyses to complete the analyses of SN1 lipolytic enzymes in the same patient. Plasma EL, HL, and LPL activities were evaluated in 59 patients with MS and 36 controls. A trend toward higher EL activity was observed in MS. EL activity was increased in obese compared with normal weight group (P=0.009) and was negatively associated with high-density lipoprotein-cholesterol (P=0.014 and P=0.005) and apoA-I (P=0.045 and P=0.001) in control and MS group, respectively. HL activity, as TG-hydrolase, was increased in MS (P=0.025) as well as in obese group (P=0.017); directly correlated with low-density lipoprotein-cholesterol (P=0.005) and apolipoprotein B (P=0.003) and negatively with high-density lipoprotein-cholesterol (P=0.021) in control group. LPL was decreased in MS (P<0.001) as well as in overweight and obese compared with normal weight group (P=0.015 and P=0.004, respectively); inversely correlated %TG-very low-density lipoproteins (P=0.04) and TG/apolipoprotein B index (P=0.013) in control group. These associations were not found in MS. We describe for the first time EL and HL activity as phospholipases in MS/obesity, being both responsible for high-density lipoprotein catabolism. Our results elucidate part of the remaining controversies about SN1 lipases activity in MS and different grades of obesity. The impact of insulin resistance on the activity of the 3 enzymes determines the lipoprotein alterations observed in these states.
    Arteriosclerosis Thrombosis and Vascular Biology 01/2014; · 6.34 Impact Factor
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    ABSTRACT: Adipose tissue produces different metalloproteinases (MMPs), involved in adipogenesis and angiogenesis. Different studies have shown that in obesity the behavior of different MMPs may be altered. However there are scarce data about the effect of insulin-resistance (IR) on MMP-2 and MMP-9 activity in adipose tissue. Our aim was to determine whether sucrose induced IR modifies MMP-2 and MMP-9 behavior in expanded visceral adipose tissue and the contribution of this tissue to circulating activity of these gelatinases. Male Wistar rats were fed with standard diet (Control) or standard diet plus 30% sucrose in the drinking water throughout 12 weeks (SRD). In epididymal adipose tissue vascular density, size and adipocyte density, PPARγ expression and MMP-2 and -9 were measured. Adipose tissue from SRD presented higher adipocyte size (6.32 ± 8.71 vs 4.33 ± 2.17 × 10(3) μm(2), p = 0.001) lower adipocyte density (164 (130-173) vs 190 (170-225) number/mm(2), p = 0.046) and lower vascular density (16.2 (12.8-23.5) vs 28.1 (22.3-46.5) blood vessels/mm(2), p = 0.002) than Control. MMP-2 and MMP-9 activity was decreased in SRD (1.93 ± 0.7 vs 3.92 ± 0.9 relative units, p = 0.048 and 1.80 ± 0.8 vs 5.13 ± 1.7 relative units, p = 0.004 respectively) in accordance with lower protein expression (0.35 ± 0.20 vs 2.71 ± 0.48 relative units, p = 0.004 and 1.12 ± 0.21 vs 1.52 ± 0.05 relative units, p = 0.036 respectively). There were no differences in PPARγ expression between groups. Insulin resistance induced by SRD decreases MMP-2 and MMP-9 activity in adipose tissue which would not represent an important source for circulating MMP-2 and -9. In this state of IR, PPARγ would not be involved in the negative regulation of adipose tissue gelatinases.
    Nutrition, metabolism, and cardiovascular diseases: NMCD 01/2014; · 3.52 Impact Factor
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    Pablo Corral, Laura Schreier
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    ABSTRACT: There is irrefutable evidence that statins reduce the risk of cardiovascular events in a magnitude proportional to the intensity of the decrease in cholesterol transport by the low density lipoproteins. Despite this great advance there is still a residual risk of cardiovascular events. For this reason, an increase in the levels of high density lipoprotein is considered in order to boost the main action of this lipoprotein, which is reverse cholesterol transport. Distinct classes of evidence (epidemiological, genetic, and pathophysiological) show that the inhibition and/or modulation of cholesterol ester transfer protein increases plasma high density lipoprotein-cholesterol levels. The main reason for presenting this review is to look at the physiology of cholesterol ester transfer protein, its interrelationship with high density lipoproteins, and to give an update on the development of different cholesterol ester transfer protein inhibitor/modulator molecules.
    Clinica e Investigacion en Arteriosclerosis 10/2013;
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    ABSTRACT: OBJECTIVE: It has been reported that LDL inhibits endothelium-dependent relaxation (EDR) and that HDL can neutralize this effect. However, the atherogenic properties of VLDL have been so far difficult to demonstrate. Studies on VLDL are controversial, and nothing is known about the role of HDL on potential VLDL vascular actions. We examined the effect of human VLDLs on EDR, and the role of HDL in this system. METHODS: VLDL (n=14) and LDL (n=6) were isolated from volunteer subjects. Normal HDL was obtained from one healthy donor. VLDL ability to inhibit ACh-induced vasorelaxation (10(-9)-10(-5)mM) on aortic rings previously precontracted by noradrenaline (10(-8)mM) was measured in presence and absence of HDL. RESULTS: ACh-induced maximal relaxation (R%) was mildly, but not significantly attenuated in the presence of VLDL (72±7%), while LDL caused a significant inhibition (60±10%, p<0.05) when compared to incubation in absence of lipoproteins. VLDLs were subdivided into 2 groups depending on their cholesterol/triglyceride ratio: 0.18-0.22 (n=8) was considered typical and 0.10-0.15, rich in triglycerides (VLDLRT, n=6). Typical VLDL had no effect on EDR (p=0.38), however R% from VLDLRT was lower (54±7%, p<0.01) similar to the one obtained with LDL (p=0.32). HDL showed favorable effects on EDR inhibition induced by the presence of VLDLRT (p<0.05.). CONCLUSION: Although typical VLDL did not cause endothelial dysfunction, triglyceride-enriched VLDL had inhibitory effect on EDR. It is proposed that alterations in VLDL composition would increase its atherogenic capacity. Moreover HDL appears to protect endothelium from VLDL action.
    Microvascular Research 06/2013; · 2.43 Impact Factor
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    ABSTRACT: The decrease in LDL-cholesterol (LDL-Chç) is consideredd the main gol in the treatment of patients with atherosclerotic cardiovascular risk: However, patients with chronic kidney disease ( CKD) on hemodialysis have LDL.C below 100 mg/dL, moderate increases in triglycerides and low frequency of HDL cholesterol values below desirable. This condition fits into the phenomenon known "reverse epidemiology" in which the normal relationship among hypercholesterolemia, high blood pressure, obesity and cardiovascular morbidity and mortality is not found.; contrary, there is a reversal in the close relationship of these parameters with cardiovascular events typical of non-hemodyalized patients. On the one hand, 35% of CKD patients have Type 2 diabetes mellitus and on the other hand, there are other lesser known pathogenic factors such as lipoprotein-associated phospholipase A2,,C reactive protein,, remnant lipoproteins, Lp(a) and enzymes and proteins associated to HDL such paraoxonase and Apo -A1. The set of factors described could replace, in CKD patients on hemodialysis, LDL-C, a typical analyte that, in other patientes, acts as a risk or pathogenic factor of atherosclerosis and not only as a circulating marker. A likely explanation for decreased LDL-C is a qualitative modification of LDL as a result of oxidation, glycation, carbamylation, ocurrence of small and dense LDL, inflammatory phenomena and malnutrition.
    Acta bioquímica clínica latinoamericana 04/2013; Acta Bioq Clin Latinoam(47(1)):95-100. · 0.09 Impact Factor
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    Laura Schreier, Regina Wikinski, Graciela López
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    Regina Wikinski, Graciela López, Laura Schreier
  • Regina Wikinski, Graciela López, Laura Schreier
  • Regina Wikinski, Graciela López, Laura Schreier
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    ABSTRACT: Resumen La disminución de colesterol-LDL (c-LDL) se considera meta principal del tratamiento de pacientes con riesgo cardiovascular. Sin embargo, pacien-tes con Enfermedad Renal Crónica (ERC) en hemodiálisis presentan c-LDL menor de 100 mg/dL, aumentos moderados de triglicéridos y baja frecuen-cia de colesterol-HDL por debajo de valores deseables. Esta condición se encuadra dentro del fenómeno conocido como "epidemiología inversa", en la cual la conocida asociación prevalente entre hipercolesterolemia, hiper-tensión arterial, obesidad y morbimortalidad por eventos cardiovasculares no se encuentra y, por el contrario se invierte la estrecha relación de estos parámetros con eventos cardiovasculares propia de los pacientes no hemo-dializados. Por un lado el 35% de los pacientes con ERC presentan diabe-tes mellitus tipo 2 y por otra parte, existen otros factores patogénicos menos conocidos como la Lipoproteína asociada a Fosfolipasa A2, la Proteína C Reactiva, los remanentes lipoproteicos, la Lp(a) y enzimas y proteínas aso-ciadas a la HDL, como la Paraoxonasa y Apo A-I. El conjunto de factores descritos podrían reemplazar, en pacientes con ERC en hemodiálisis, al colesterol-LDL (c-LDL), típico analito que en otros pacientes actúa como factor de riesgo y/o patogénico de aterosclerosis y no sólo como marcador circulante. Una explicación plausible respecto al c-LDL disminuído es la modificación cualitativa de LDL por oxidación, glicación, carbamilación, la presencia de LDL pequeñas y densas, fenómenos inflamatorios y mal-nutrición.
    Acta bioquímica clínica latinoamericana ISSN 0325,2957. 01/2013; 47(1):95:100.
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    Pablo Corral, Laura Schreier
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    ABSTRACT: There is irrefutable evidence that statins reduce the risk of cardiovascular events in a magnitude proportional to the intensity of the decrease in cholesterol transport by the low density lipoproteins. Despite this great advance there is still a residual risk of cardiovascular events. For this reason, an increase in the levels of high density lipoprotein is considered in order to boost the main action of this lipoprotein, which is reverse cholesterol transport. Distinct classes of evidence (epidemiological, genetic, and pathophysiological) show that the inhibition and/or modulation of cholesterol ester transfer protein increases plasma high density lipoprotein-cholesterol levels. The main reason for presenting this review is to look at the physiology of cholesterol ester transfer protein, its interrelationship with high density lipoproteins, and to give an update on the development of different cholesterol ester transfer protein inhibitor/modulator molecules.
    Clínica e Investigación en Arteriosclerosis 01/2013;
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    ABSTRACT: OBJECTIVE: A novel phospholipase assay was used to measure for the first time the behavior of endothelial and hepatic phospholipase activities in postheparin human plasma of hemodialyzed patients and its relationship with atherogenic and antiatherogenic lipoprotein levels. METHODS AND RESULTS: Endothelial and hepatic phospholipase activity was assessed in a total SN1-specific phospholipase assay, using (1-decanoylthio-1-deoxy-2-decanoyl-sn-glycero-3-phosphoryl) ethylene glycol as the substrate. Hemodialyzed patients presented lower values of total and hepatic phospholipase activity than controls: 4.4 (1.9-9.0) versus 7.5 (3.6-18.0) and 2.6 (0.7-6.2) versus 6.6 (1.3-15.2) μmol of fatty acid released per milliliter of postheparin plasma per hour, respectively (P<0.001); however, endothelial lipase (EL) phospholipase activity was increased in patients: 1.7 (0.8-3.0) versus 1.1 (0.1-2.7) μmol of fatty acid released per milliliter of postheparin plasma per hour (P=0.008). EL was negatively associated with high-density lipoprotein (HDL)-cholesterol (r=-0.427; P=0.001), and apolipoprotein A-I levels, total phospholipase, and hepatic lipase activity were directly associated with low-density lipoprotein-cholesterol and apolipoprotein B. The association of EL and HDL-cholesterol remained significant when adjusting for waist circumference (β=-0.26; P=0.05), and the effect of hepatic lipase on low-density lipoprotein-cholesterol continued after adjusting for age (β=0.46; P= 0.001). CONCLUSIONS: Our results support the hypothesis that EL is the predominant enzyme responsible for lipolytic catabolism of HDLs in hemodialyzed patients and resolve the apparent paradox observed between low hepatic lipase activity and decreased HDL-cholesterol levels observed in these patients. In addition, the ability to assess total hepatic lipase and EL phospholipase activity in plasma will increase our knowledge of the mechanisms involved in controlling HDL levels and cardiovascular risk in hemodialyzed patients, as well as other populations with low levels of HDL-cholesterol.
    Arteriosclerosis Thrombosis and Vascular Biology 10/2012; · 6.34 Impact Factor
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    ABSTRACT: BACKGROUND: HDL antiatherogenic effects would not only depend on its concentration but also on its biological quality. Hepatic lipase (HL) action on HDL acts in one of the last steps of reverse cholesterol transport. Cardiovascular risk increases after menopause, however HDL does not decrease even when HL is increased. We evaluated HDL capacity as a substrate of HL in healthy postmenopausal women (PMW). METHODS: We studied 20 PMW (51-60y) and 20 premenopausal (PreMW) (26-40y). In fasting serum, lipid-lipoprotein profile and HDL composition were assessed. Optimal assay conditions for HDL/HL ex vivo incubation were established. Increasing HDL-triglyceride concentrations (0.015 to 0.20mmol/l) were incubated with post-heparin plasma obtained from a single healthy donor as a source of HL. Free fatty acids were measured and kinetic parameters calculated: K(m)(app), inverse to enzyme affinity, and V(max). RESULTS: HDL composition in PMW exhibits triglyceride enrichment (p<0.001). Kinetic analysis revealed higher K(m)(app) in PMW [130 (40-380) vs 45 (20-91) mmol/l, p<0.0001)] correlating directly with HDL-triglycerides (r=0.7, p=0.0001). Catalytic efficiency, V(max)/K(m)(app) was reduced when compared to controls (p=0.0001). CONCLUSION: Triglyceride-enriched HDL from PMW constitutes a poor substrate for HL suggesting that this particle may not exert efficiently its antiatherogenic function, regardless of plasma concentration.
    Clinica chimica acta; international journal of clinical chemistry 09/2012; 414C:142-145. · 2.54 Impact Factor
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    ABSTRACT: It has been hypothesized that deviations in glucocorticoid secretion and/or action may contribute to somatic and biochemical changes observed in patients with and animal models of insulin resistance (IR). In this study, we analyzed changes in rat adrenocortical function and morphology associated with the development of IR, generated in male adult rats by the addition of 30% sucrose to the drinking water. Caloric intake, body and adipose tissue weights, and biochemical parameters associated with IR were determined. Expression levels of Star, Cyp11A1, Mc2r, Pparγ (Pparg), and Cd36 were evaluated by real-time PCR, histochemical analysis of the adrenal cortex was performed using Masson's trichrome and Sudan III staining, and corticosterone levels were measured by RIA. After 7 weeks of sucrose administration, higher serum glucose, insulin, and triglyceride levels and an altered glycemic response to an i.p. insulin test were detected. Adrenal glands showed a neutral lipid infiltration. An increase in Star, Cyp11A1, Mc2r, Pparg and Cd36 and a decrease in Mc2r levels were also found. Furthermore, sucrose-treated animals exhibited higher basal corticosterone levels and a blunted response to ACTH injection. Noteworthy, the adrenocortical (functional and histological) abnormalities were prevented in sucrose-treated rats by the simultaneous administration of an insulin-sensitizing PPARγ agonist. In conclusion, sucrose-induced IR affects adrenocortical morphology and function possibly via the generation of adipokines or lipid metabolites within the adrenal gland. These abnormalities are prevented by the administration of a PPARγ agonist by mechanisms involving both extra- and intra-adrenal effects.
    Journal of Endocrinology 06/2012; 214(3):267-76. · 3.59 Impact Factor

Publication Stats

680 Citations
263.11 Total Impact Points

Institutions

  • 1995–2014
    • University of Buenos Aires
      • • Clinical Biochemistry Department
      • • Institute of Pathophysiology and Clinical Biochemistry (INFIBIOC)
      • • Faculty of Pharmacy and Biochemistry
      Buenos Aires, Buenos Aires F.D., Argentina
  • 2011
    • Administración Nacional de Laboratorios e Institutos de Salud (Argentina)
      Buenos Aires, Buenos Aires F.D., Argentina
  • 2007
    • Hospital Español de Buenos Aires
      Buenos Aires, Buenos Aires F.D., Argentina