Boel Wallin

University of Gothenburg, Goeteborg, Västra Götaland, Sweden

Are you Boel Wallin?

Claim your profile

Publications (9)23.09 Total impact

  • Atherosclerosis Supplements 06/2007; 8(1):10-10. DOI:10.1016/S1567-5688(07)70984-4 · 2.29 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The dyslipidemia of insulin resistance, with high levels of albumin-bound fatty acids, is a strong cardiovascular disease risk. Human arterial smooth muscle cell (hASMC) matrix proteoglycans (PGs) contribute to the retention of apoB lipoproteins in the intima, a possible key step in atherogenesis. We investigated the effects of high NEFA levels on the PGs secreted by hASMCs and whether these effects might alter the PG affinity for low-density lipoprotein. hASMC exposed for 72 hours to high concentrations (800 micromol/L) of linoleate (LO) or palmitate upregulated the core protein mRNAs of the major PGs, as measured by quantitative PCR. Insulin (1 nmol/L) and the PPARgamma agonist rosiglitazone (10 micromol/L) blocked these effects. In addition, high LO increased the mRNA levels of enzymes required for glycosaminoglycan (GAG) synthesis. Exposure to NEFA increased the chondroitin sulfate:heparan sulfate ratio and the negative charge of the PGs. Because of these changes, the GAGs secreted by LO-treated cells had a higher affinity for human low-density lipoprotein than GAGs from control cells. Insulin and rosiglitazone inhibited this increase in affinity. The response of hASMC to NEFA could induce extracellular matrix alterations favoring apoB lipoprotein deposition and atherogenesis.
    Arteriosclerosis Thrombosis and Vascular Biology 02/2006; 26(1):130-5. DOI:10.1161/01.ATV.0000191659.94059.62 · 6.00 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Insulin resistance, impaired glucose tolerance, high circulating levels of free fatty acids (FFA), and postprandial hyperlipidemia are associated with the metabolic syndrome, which has been linked to increased risk of cardiovascular disease. We studied the metabolic responses to an oral glucose/triglyceride (TG) (1.7/2.0 g/kg lean body mass) load in three groups of conscious 7-h fasted Zucker rats: lean healthy controls, obese insulin-resistant/dyslipidemic controls, and obese rats treated with the dual peroxisome proliferator-activated receptor alpha/gamma agonist, tesaglitazar, 3 for 4 wk. Untreated obese Zucker rats displayed marked insulin resistance, as well as glucose and lipid intolerance in response to the glucose/TG load. The 2-h postload area under the curve values were greater for glucose (+19%), insulin (+849%), FFA (+53%), and TG (+413%) compared with untreated lean controls. Treatment with tesaglitazar lowered fasting plasma glucose, improved glucose tolerance, substantially reduced fasting and postload insulin levels, and markedly lowered fasting TG and improved lipid tolerance. Fasting FFA were not affected, but postprandial FFA suppression was restored to levels seen in lean controls. Mechanisms of tesaglitazar-induced lowering of plasma TG were studied separately using the Triton WR1339 method. In anesthetized, 5-h fasted, obese Zucker rats, tesaglitazar reduced hepatic TG secretion by 47%, increased plasma TG clearance by 490%, and reduced very low-density lipoprotein (VLDL) apolipoprotein CIII content by 86%, compared with obese controls. In conclusion, the glucose/lipid tolerance test in obese Zucker rats appears to be a useful model of the metabolic syndrome that can be used to evaluate therapeutic effects on impaired postprandial glucose and lipid metabolism. The present work demonstrates that tesaglitazar ameliorates these abnormalities and enhances insulin sensitivity in this animal model.
    AJP Regulatory Integrative and Comparative Physiology 11/2005; 289(4):R938-46. DOI:10.1152/ajpregu.00252.2005 · 3.11 Impact Factor

  • Atherosclerosis Supplements 04/2005; 6(1):16-16. DOI:10.1016/S1567-5688(05)80061-3 · 2.29 Impact Factor

  • G Camejo · B Wallin · M Enojärvi ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Measurement of thiobarbituric acid reacting substances (TBARS), diene derivatives, and hydroperoxides are probably the most widely used procedures for evaluation of free radical-mediated oxidation of biological or model systems containing polyunsaturated fatty acids (PUFA). It is possible to write a sequence of rational reactions in which dienes formation comes first, followed by lipid hydroperoxides (LOOHs) production, and that terminates with fragmentation of the PUFA chains to carbonyl compounds that are TBARS. However, it appears that after the first few min, species of the three types co-exist even in simple suspensions of linoleic acid (1,2). These compounds are very reactive, especially in biological systems, and follow different rates of formation and conversion. Therefore, it is more informative to follow their kinetics of appearance and disappearance than to measure single time-points (3–5).
    Methods in Molecular Biology 02/1998; 108:377-87. DOI:10.1385/0-89603-472-0:377 · 1.29 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The atherogenicity of low density lipoproteins (LDL) may be modulated by its serum levels, structure and affinity for components of the intima, all properties that can be altered by diet. Linoleic acid-rich diets (n-G, 18:2) reduce the levels of LDL whereas those rich in oleic (n-9,18:1) are considered 'neutral'. However, LDL enriched in linoleic acid have been reported to be more vulnerable to free radical-mediated oxidation than those enriched in oleic, a potentially atherogenic property. The effect of dietary fats on other properties of LDL that may also modulate atherogenesis, such as size and capacity to interact with intima components, are not well established. We explored here how a change from an olive oil-rich diet (OO) to a sunflower oil-rich one (SFO) affects these parameters in a community with a traditional Mediterranean diet. Eighteen free-living volunteers were placed for 3 weeks on a diet with 31% of caloric intake as sunflower oil and then shifted for an additional 3 weeks to a diet in which OO provided 30.5% of the calories. The LDL after SFO had a fatty acids ratio of (18:2 + 18:3 + 20:4) to (16:0 + 16:1 + 18:0 + 18:1) of 1.06 +/- 0.11 compared to 0.73 +/- 0.06 after the OO period. Serum LDL was significantly lower after SFO than after OO. Unexpectedly, copper-catalyzed oxidation of LDL from the SFO period was significantly less than that of the particles from the OO period. The resistance to oxidation of LDL of the SFO and OO period related to alterations in content of the antioxidants alpha-tocopherol, beta-carotene and retinol, in addition to changes in size and fatty acids composition. In vitro binding of LDL to human arterial proteoglycans was also significantly lower for the SFO-LDL than the OO-LDL, a result that can also be attributed to the larger size of the SFO-LDL. Therefore, three properties of LDL: circulating levels, oxidizability, and affinity with intima proteoglycans, that may modulate its atherogenicity, were shifted in a favorable direction by diets rich in linoleic acid and natural antioxidants.
    Atherosclerosis 10/1996; 125(2):243-55. DOI:10.1016/S0021-9150(96)05882-0 · 3.99 Impact Factor
  • B Wallin · G Camejo ·
    [Show abstract] [Hide abstract]
    ABSTRACT: The oxidative modification of lipoproteins is of clinical importance because of potential contribution to atherogenesis [1, 2, 3]. An early step in the complex process of oxidation is the peroxidation of polyunsaturated fatty acids. We describe here a method for the Cu(II)-catalyzed oxidation of human low density lipoproteins with the subsequent analysis of hydroperoxides formation in a single microtitre plate. The procedure includes a modification of an iodometric peroxide assay for test tubes using a commercially available reagent. The microtitre plate method correlated well with the test tube procedure (r = 0.99) and showed comparable sensitivity and reproducibility. It was sensitive down to 0.5 nmol hydroperoxides/well and linear up to at least 20 nmol well-1. The method can handle several hundreds of samples a day with considerably less labour than the test tube procedure. It was well suited to monitor the kinetics of lipoprotein oxidation. The method was also used to test the potency of antioxidants, however, some antioxidants may interfere with the iodometric reaction and should be tested in the assay before use.
    Scandinavian Journal of Clinical and Laboratory Investigation 08/1994; 54(4):341-6. DOI:10.3109/00365519409087532 · 1.90 Impact Factor
  • B Wallin · B Rosengren · H G Shertzer · G Camejo ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Transition metals catalyze free radical-mediated oxidation of lipids and lipoproteins. This process is currently studied because of its potential relevance to pathological processes like atherosclerosis. Formation of thiobarbituric acid-reacting substances from polyenoic fatty acids is frequently used to follow oxidation of lipids and plasma lipoproteins. We describe here how Cu(II)- and Fe(III)-catalyzed oxidation of human low density lipoprotein or soy bean phospholipids and the photometric evaluation of the thiobarbituric acid-reaching substances formed can be conducted in the same 96-well microtiter plate. The procedure showed a correlation of 0.98 with conventional two-stage fluorimetric and spectrophotometric methods and also showed better reproducibility. The plate method can handle up to one plate per hour with considerably less labor than the test tube assays. The plate procedure required small volumes of diluted samples of lipoproteins lipids and reagents. The method was suitable for testing the concentration-dependent antioxidant potency of substances like probucol, butylated hydroxytoluene, and alpha-tocopherol. The method can also be used to follow the kinetics of oxidation of lipoproteins.
    Analytical Biochemistry 02/1993; 208(1):10-5. DOI:10.1006/abio.1993.1002 · 2.22 Impact Factor