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M Kus

Publications and source records attributed to M Kus.

At least 19 recordsLinked to original sources
PubMed1996

Hydroxypropyl-beta-cyclodextrin-mediated efflux of 7-ketocholesterol from macrophage foam cells.

Atherosclerosis involves the arterial accumulation of lipid-laden "foam cells" containing oxidized and unoxidized sterols and their esters (Mattsson-Hulten, L., Lindmark, H., Diczfalusy, U., Bjorkhem, I., Ottosson, M., Liu, Y., Bondjers, G., and Wiklund, O. (1996) J. Clin. Invest. 97, 461-8). Oxidized sterols are probably critical to atherogenesis because they inhibit cholesterol removal from cells and are cytotoxic. We recently reported that there is deficient induction of cellular cholesterol efflux by apolipoprotein A-I, the main initial acceptor of cellular cholesterol from macrophages loaded in vitro with oxidized low density lipoprotein (Kritharides, L., Jessup, W., Mander, E., and Dean, R. T. (1995) Arterioscler. Thromb. 15, 276-289). There was an even more marked impairment of the release of 7-ketocholesterol which is a major oxysterol in these cells and in human atherosclerotic lesions. Here we show that hydroxypropyl-beta-cyclodextrin can induce selective efflux of 7-ketocholesterol. Efflux of 7-ketocholesterol was time and concentration dependent, and the rate of its removal was 50-fold greater for hydroxypropyl-beta-cyclodextrin than for apolipoprotein A-I. Over a defined range of concentrations (0-5 mg/ml), efflux of 7-ketocholesterol was preferred over that of cholesterol and occurred without cell toxicity. Efflux of free 7-ketocholesterol was associated with decreased intracellular free and esterified 7-ketocholesterol. Hydroxypropyl-beta-cyclodextrin also enhanced efflux of other oxysterols. The physical solubilization of 7-ketocholesterol by the cyclodextrin was much greater than that of cholesterol, in accordance with its differential effects on efflux. These data highlight the importance of extracellular sterol solubilization in the efflux of cellular oxysterols and the mobilization of intracellular free and esterified oxysterol pools in macrophages loaded with oxidized low density lipoprotein. Synthetic sterol-solubilizing agents such as hydroxypropyl-beta-cyclodextrin are thus potential prototypes for the further development of oxysterol-removing agents.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1994

Effect of duration of ischaemia on reduction of myocardial infarct size by inhibition of neutrophil accumulation using an anti-CD18 monoclonal antibody.

1. Neutrophil accumulation is a characteristic feature of the inflammatory response in myocardial tissue which has undergone a period of ischaemia. The aim of this study was to examine whether inhibition of myocardial neutrophil infiltration, using an antibody to the CD18 leukocyte adhesion molecule, was effective in reducing infarct size in anaesthetized rabbits. 2. Anaesthetized rabbits underwent coronary artery occlusion (CAO) for periods of 30 or 45 min followed by reperfusion for 3 h. Animals were treated intravenously 10 min prior to reperfusion with IB4, a monoclonal antibody to CD18 (1 mg kg-1) or saline (1 ml kg-1). In one group undergoing 45 min CAO, a control antibody, OKMI (1 mg kg-1) was given. 3. Following either 30 or 45 min of CAO, administration of IB4 resulted in a < 75% inhibition in neutrophil accumulation in the area at risk myocardium (AR) compared with control animals. 4. With the 30 min occlusion period, IB4 significantly reduced myocardial infarct size, 27.2 +/- 3.2% vs 67.4 +/- 5.6% in the saline control group (n = 5 P < 0.01). In contrast, IB4 did not reduce infarct size following a 45 min period of ischaemia. 5. In the same animals administration of IB4 significantly inhibited oedema formation in skin elicited by intradermal administration of the neutrophil chemoattractant f-Met-Leu-Phe, but had no effect on coronary microvascular plasma protein leakage in the AR. 6. Our results indicate that infiltrating neutrophils exacerbate tissue injury following a relatively short, 30 min period of myocardial ischaemia in the rabbit. However, protection with IB4 was no longer seen if the period of CAO was extended to 45 min. The results in this model suggest neutrophils are not a major determinant of tissue injury following more than a very short period of ischaemia.

Animals↗
PubMed1993

Trimetazidine inhibits neutrophil accumulation after myocardial ischaemia and reperfusion in rabbits.

Interventions that inhibit neutrophil infiltration into myocardial tissue after ischaemia and reperfusion are reported to reduce the size of the infarct. We examined whether administration of trimetazidine, which is reported to reduce myocardial infarct size, affects this process. [111In]Neutrophils and [125I]albumin were administered intravenously (i.v.) to anaesthetized rabbits to allow measurement of cell accumulation and changes in microvascular plasma protein leakage. A 30-min period of coronary artery occlusion followed by 3-h reperfusion was used, and the area at risk (AR) myocardium was defined by dye exclusion. Twelve rabbits received 2.5 mg/kg trimetazidine i.v., 10 min before coronary artery occlusion; the 13 controls received saline. In the control group, the number of [111In]neutrophils/g tissue in the AR (30,591 +/- 6,725) was significantly greater than in the normal zone (NZ, 11,519 +/- 1,605, p < 0.01). In the trimetazidine-treated group, the number of [111In]neutrophils in the AR was significantly lower than in the control group (12,717 +/- 1,958 [111In]neutrophils/g, p < 0.01). There was no significant difference in neutrophil content of the NZ (7,832 +/- 1,117 [111In]neutrophils/g) in treated animals as compared with that in control. Accumulation of [111In]neutrophils in response to intradermal administration of leukotriene B4, interleukin-8 (IL-8), or zymosan-activated plasma was not affected by the drug. The effect of trimetazidine on neutrophil accumulation into post-ischaemic reperfused myocardium therefore does not appear to result from a direct action on the neutrophil.

Animals↗
PubMed1992

Alpha-tocopherol, lipids and lipoproteins in knee-joint synovial fluid and serum from patients with inflammatory joint disease.

1. We have determined the antioxidant status of synovial fluid and serum of patients with inflammatory joint disease in terms of the biologically active lipid-soluble antioxidant, alpha-tocopherol. Synovial fluid concentrations of alpha-tocopherol were significantly lower relative to those of paired serum samples (P < 0.001). Serum levels of alpha-tocopherol in these patients did not differ significantly from those in control serum. 2. Lower concentrations of cholesterol, triacylglycerol and low-density lipoprotein were also observed in patients' synovial fluid compared with matched serum samples. However, multiple regression analysis of the data indicated that there remained a significant depletion of alpha-tocopherol, which was largely independent of these co-variables, in inflammatory synovial fluid. These findings are consistent with the consumption of alpha-tocopherol within the inflamed joint via its role in terminating the process of lipid peroxidation. 3. Nuclear magnetic resonance spectroscopic analysis of matched inflammatory synovial fluid and serum confirmed lower concentrations of triacylglycerol in synovial fluid together with evidence of a shortened mean triacylglycerol chain length. The latter metabolic difference suggests an increased utilization of triacylglycerols for energy within the inflamed joint.

Arthritis↗