Haptoglobin expression and activity during coronary collateralization

Abstract

Coronary collateral development relies on the coordinated secretion of growth factors. However, alone they are insufficient for permanent collateral growth. We utilized proteomics to identify other important proteins in the extracellular environment that could facilitate collateralization. Chronically instrumented dogs developed coronary collaterals by the repetitive occlusion method. Subendocardial (0.19 Ϯ 0.04, 0.27 Ϯ 0.06, 0.48 Ϯ 0.10, and 0.81 Ϯ 0.11 ml ⅐ min Ϫ1 ⅐ g Ϫ1 on days 1, 7, 14, and 21, respectively) and subepicardial (0.14 Ϯ 0.01, 0.36 Ϯ 0.06, 0.51 Ϯ 0.07, and 0.71 Ϯ 0.08 ml ⅐ min Ϫ1 ⅐ g Ϫ1 on days 1, 7, 14, and 21, respectively) blood flow increased in animals subjected to repetitive occlusion. Sham animals exhibited no changes in blood flow. Myocardial interstitial fluid (MIF) from both groups was analyzed by two-dimensional electrophoresis with matrix-assisted laser desorption/ionization time-of-flight identification. The acute-phase protein haptoglobin was identified in the group subjected to repetitive occlusion. ELISA of MIF showed haptoglobin to be elevated at all time points of collateral development compared with sham, with maximal production on day 7. Purified haptoglobin dose dependently stimulated endothelial cells to form tubes and vascular smooth muscle cells to migrate. Purified haptoglobin did not stimulate proliferation of either cell type. The relative contribution of haptoglobin to the chemotactic properties of MIF was tested using a neutralizing antibody. Neutralized MIF could not stimulate smooth muscle cells to migrate at any time during collateral development. Endothelial cell tube formation was inhibited after the midpoint of collateralization. Therefore, the acute-phase protein haptoglobin plays a critical role during coronary collateralization.angiogenesis; coronary circulation; inflammation; proteins CORONARY ARTERY DISEASE is characterized by plaque deposition, which ultimately reduces blood flow and leads to the pathophysiological sequelae of ischemic heart disease. Clinical data demonstrate that development of the coronary collateral circulation can ameliorate complications of coronary disease. Perez-Castellano et al. (33) associated reduced patient mortality from myocardial infarction with the extent of collateral development. Coronary collaterals can also reduce infarct size, preserve myocardial architecture, and improve cardiac function (5, 19).Coronary collaterals are preexisting arterial anastomoses between coronary arteries. These vessels cannot conduct blood flow sufficient to prevent ischemia in the event of coronary occlusion because of their small caliber and high resistance in their native state (10). However, collaterals can dramatically increase in diameter and muscularity when stimulated (10). Vascular endothelial growth factor (VEGF) has been identified as important in collateralization, and administration of VEGF or transfection in vivo enhances angiogenesis and collateral growth in many models (4,23,24,26). Basic fibroblast growth factor (bFGF), a mitog...

Acute phase proteins activation in subjects with coronary atherosclerosis and micro-vessel coronary circulation impairment

“…Schalkwijk et al detected raised A1GP levels in patients with indirect signs of endothelial activation [32]. Involvement of iron metabolism in conditioning endothelial function has been documented [33] and an APP acting on iron levels such as HG has been reported as connected with development of collateral coronary flow [2,34].…”

Myocardial interstitial fluid inhibits proliferation and cardiomyocyte differentiation in pluripotent embryonic stem cells

“…For each experiment, pools representing 3 consecutive days of collection of iMIF or sMIF, termed "MIF collection pools," were used to supplement RPMI/B27 at a concentration of 10% vol/vol, the level of which was selected based on previous experiments evaluating the effects of iMIF on vascular cell lines (36). Most experiments used the following MIF collection pools: days 1-3, 7-9, 13-15, and 22-24. The selection of these pools was based on findings from previous studies (22,23,36).…”

“…iMIF was collected over 24 consecutive days by injecting 4 ml lactated Ringer solution into the catheter while simultaneously harvesting 4 ml MIF from the effluent end. It is estimated that this procedure causes a 20-fold dilution of the iMIF as calculated from the catheter volume (22). A control sham-operated dog that was identically instrumented was not occluded; sham-operated MIF (sMIF) was collected in parallel with iMIF.…”

“…As a first step, we have used a model wherein the effects of ischemic myocardial interstitial fluid (iMIF), harvested from myocardium during a 24-day period of transient ischemia, can be evaluated on the in vitro behavior of pluripotent stem cells. Previous work has shown that iMIF induces an angiogenic response, inducing the proliferation of vascular smooth muscle and endothelial cell lines (22,23,36). However, the effects of iMIF on pluripotent stem cells have not been assessed.…”

Coronary collaterals—insights in molecular determinants and prognostic relevance

“…Indeed, our own preliminary data in patients suggest that polymorphisms of the tumor necrosis factor-alpha promotor region are related to the extent of collateral circulation as visible by angiography. Interestingly, a study in dogs revealed that upregulation of the acute phase protein haptoglobin in the myocardial interstitial fluid could stimulate migration of vascular smooth muscle cells and collateral formation [34]. Earlier, Hochberg et al had suggested haptoglobin 2-2 in diabetics [35] as a genetic determinant of the extent of coronary collaterals.…”