Yair Galili, MD and Arie Bass, MD
Peter C. Harpel, MD and Nasreen S. Haque, PhD
Chemokines and their receptors play regulatory roles in inflammatory reactions. Lipoprotein(a) is an atherogenic lipoprotein, however the mechanisms of its actions are not defined. Our interest in chemokines and their receptors was stimulated by the finding that incubation of Lp(a) with human umbilical vein endothelial cells produced a conditioned medium that was chemotactic for human monocytes. Since infiltration of monocytes into the vessel wall is an early lesion in atherosclerosis, this finding provided a novel mechanism to explain the relationship between Lp(a) and atherosclerosis. The chemoattractant produced by HUVEC was identified as CCL1/I-309, a CC chemokine previously reported to be secreted by stimulated monocytes/macrophages and T lymphocytes. CCR8, the CCL1 receptor, was identified on endothelial cells, and CCL1 was found to be a chemoattractant for these cells. Most recently we demonstrated functional CCR8 on human vascular smooth muscle cells and found that the Lp(a)-HUVEC conditioned medium is a chemoattractant for these cells. CCL1 increased metalloproteinase-2 production by HUVEC, an activity that enables these cells to remodel the vascular matrix. These studies suggest that CCR8 may play an important role in arterial wall pathology.
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Lp(a) = lipoprotein(a)
HUVEC = human umbilical vein endothelial cells
Seth J. Corey, MD and Quan-Sheng Zhu, MD
Philip Vaughan, MBBS, Jeremy Gardner, MBBS, Francesca Peters, MBBS, MRCP and Rosalind Wilmott, RGN
Htwe. M. Zaw, MBBS, MRCS, Ian. C. Osborne, MBBS, Philip. N. Pettit, MBBS, MRCS, and Alexander. T. Cohen, MBBS, MSc, MD, FRACP
Tomas Ganz, PhD, MD
Systemic infection or inflammation causes a decrease in intestinal iron absorption and impairs the release of recycled iron from macrophages. Decreased availability of iron may deny this essential element to invading pathogens and may inhibit their multiplication and other metabolic processes but also results in anemia of chronic disease. This article reviews recent discoveries that shed light on the regulation of iron metabolism during infection and iron overload, and point to the central role of a newly discovered peptide, hepcidin. Evidence to date indicates that hepcidin is a negative regulator of intestinal iron absorption, placental iron transport, and the release of iron from macrophages that recycle iron from senescent red cells. It may also be the central mediator of iron sequestration during infections and inflammatory states and the mediator of anemia of chronic disease. Rapid progress in this area is a good example of the beneficial effects of improvements in peptide analysis and chemistry, advances in genomics, and the increasing use of transgenic mice to determine the function of newly discovered genes and proteins.
Liat Nadav, MD, Benjamin Geiger, PhD and Ben-Zion Katz, PhD
Avinoam Shuper, MD, Batia Stark, MD, Liora Kornreich, MD, Ian J. Cohen, MBChB, Gali Avrahami, MD and Isaac Yaniv, MD
The addition of methotrexate to treatment protocols in children with acute lymphoblastic leukemia has been found beneficial in preventing central nervous system relapse. However, MTX itself may be associated with neurologic morbidities, the most significant of which is leukoencephalopathy. The present study describes the clinical spectrum of leukoencephalopathy, which ranges from a subclinical disease manifested only radiologically to a progressive, devastating encephalopathy. The interaction of MTX with other components of the treatment protocol is discussed, as is the effect of leucovorin. A summary is presented of the metabolic pathways that may be involved in the development of MTX toxicity. Researchers are still seeking a biochemical marker to aid in the determination of the amount of MTX that may be safely administered.
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Arnon Blum, MD, Julia Sheiman, MD and Yonathan Hasin, MD
Joseph D. Rosenblatt, MD, Seung-Uon Shin, PhD, Hovav Nechustan, MD, PhD, Kyung Hee Yi, BSc and Khaled Tolba, MD
Pesach. J. Shteper, MSc and Dina Ben-Yehuda, MD
Jacob Cohen, MSc, Lia Supino-Rosin, MSc, Eran Barzilay, BSc, Ronit Eisen-Lev, DMD, Moshe Mittelman, MD and Drorit Neumann, PhD