[Show abstract][Hide abstract] ABSTRACT: Complement inhibition by C1-inhibitor has been shown to reduce myocardial ischaemia-reperfusion injury in animal models. We therefore studied the effects of intravenous C1-inhibitor, following reperfusion therapy, in patients with acute myocardial infarction.
C1-inhibitor therapy was started not earlier than 6h after acute myocardial infarction, in order to prevent interference with thrombolytic therapy. A loading dose of C1-inhibitor was followed by a continuous infusion for 48 h, using three escalating dosage schemes. Efficacy of complement inhibition was estimated from C4 activation fragments. Plasma concentrations of myocardial proteins were compared to values measured in matched control patients. In 22 patients, C1-inhibitor was well tolerated and drug-related adverse events were not observed. Target plasma levels of C1-inhibitor were reached, with values of 48.2 ml.kg(-1) for distribution space and 35.5h for the half-life time of C1-inhibitor. A dose-dependent reduction of C4 fragments was found P=0.005). In 13 patients who received early thrombolytic therapy, release of troponin T and creatine kinase-MB(mass) was reduced by 36% and 57%P =0.001), compared to 18 controls.
Continuous 48-h treatment with C1-inhibitor provides safe and effective inhibition of complement activation after reperfused acute myocardial infarction and may reduce myocardial injury.
Full-text · Article · Dec 2002 · European Heart Journal
[Show abstract][Hide abstract] ABSTRACT: We studied a possible effect of the extent of the acute phase response after acute myocardial infarction on the cumulative release of troponin T. The height of the acute phase response might influence the cumulative release of troponin T, bound to the myofibrillar structures of the heart, in a different way compared to the free cytoplasmic cardiac marker hydroxybutyrate dehydrogenase (EC 188.8.131.52). To investigate this, the cumulative amount of C-reactive protein in plasma, i.e. the quantified acute phase response, was related to the cumulative plasma release of hydroxybutyrate dehydrogenase (an established method for infarct sizing) on the one hand and to that of troponin T on the other hand. The study was performed in patients receiving (n=16) and in patients not receiving (n=6) thrombolytic therapy. Cumulative protein release was calculated using a two-compartment model for circulating proteins. Conclusions: The cumulative amount of plasma C-reactive protein is significantly higher in the patients not receiving thrombolytic therapy, as is in accordance with earlier studies. The cumulative amount of troponin T released is significantly related to the cumulated concentration of C-reactive protein, especially in patients not receiving thrombolytic therapy. The intensity of the acute phase response, estimated from cumulative plasma C-reactive protein response, has no effect on the relative proportions of troponin T and hydroxybutyrate dehydrogenase released into plasma.
No preview · Article · Nov 2000 · Clinical Chemistry and Laboratory Medicine
[Show abstract][Hide abstract] ABSTRACT: Myoglobin and fatty acid-binding protein (FABP) each are useful as early biochemical markers of muscle injury. We studied whether the ratio of myoglobin over FABP in plasma can be used to distinguish myocardial from skeletal muscle injury.
Myoglobin and FABP were assayed immunochemically in tissue samples of human heart and skeletal muscle and in serial plasma samples from 22 patients with acute myocardial infarction (AMI), from 9 patients undergoing aortic surgery (causing injury of skeletal muscles), and from 10 patients undergoing cardiac surgery. In human heart tissue, the myoglobin/FABP ratio was 4.5 and in skeletal muscles varied from 21 to 73. After AMI, the plasma concentrations of both proteins were elevated between approximately 1 and 15 to 20 hours after the onset of symptoms. In this period, the myoglobin/FABP ratio was constant both in subgroups of patients receiving and those not receiving thrombolytics and amounted to 5.3 +/- 1.2 (SD). In serum from aortic surgery patients, both proteins were elevated between 6 and 24 hours after surgery; the myoglobin/FABP ratio was 45 +/- 22 (SD), which is significantly different from plasma values in AMI patients (P < .001). In patients with cardiac surgery, the ratio increased from 11.3 +/- 4.7 to 32.1 +/- 13.6 (SD) during 24 hours after surgery, indicating more rapid release of protein from injured myocardium than from skeletal muscles.
The ratio of the concentrations of myoglobin over FABP in plasma from patients with muscle injury reflects the ratio found in the affected tissue. Since this ratio is different between heart (4.5) and skeletal muscle (20 to 70), its assessment in plasma allows the discrimination between myocardial and skeletal muscle injury in humans.
[Show abstract][Hide abstract] ABSTRACT: Cellular fatty acid-binding proteins (FABP) are a highly conserved family of proteins consisting of several subtypes, among them the mammary-derived growth inhibitor (MDGI) which is quite homologous to or even identical with the heart-type FABP (H-FABP). The FABPs and MDGI have been suggested to be involved in intracellular fatty acid metabolism and trafficking. Recently, evidence for growth and differentiation regulating properties of MDGI and H-FABP was provided. Using four affinity-purified polyclonal antibodies against bovine and human antigen preparations, the cellular localization of MDGI/H-FABP in human and mouse tissues and organs was studied. The antibodies were weakly cross-reactive with adipose tissue extracts known to lack H-FABP, but failed to react by Western blot analysis with liver-type FABP (L-FABP) and intestinal-type FABP (I-FABP). MDGI/H-FABP protein was mainly detected in myocardium, skeletal and smooth muscle fibres, lipid and/or steroid synthesising cells (adrenals, Leydig cells, sebaceous glands, lactating mammary gland) and terminally differentiated epithelia of the respiratory, intestinal and urogenital tracts. The results provide evidence that expression of H-FABP is associated with an irreversibly postmitotic and terminally differentiated status of cells. Since all the antisera employed showed spatially identical and qualitatively equal immunostaining, it is suggested that human, bovine and mouse MDGI/H-FABP proteins share highly homologous epitopes.
[Show abstract][Hide abstract] ABSTRACT: There are substantial amounts of cytoplasmic heart-type fatty-acid-binding protein (FABP) (15 kDa) in myocardial tissue. The rapid release of FABP into plasma during ischaemia indicates the possibility of using this protein as a biochemical marker for ischaemic myocardial injury.
To study the completeness of the release of FABP from damaged tissue in patients with acute myocardial infarction (AMI) and the suitability of serial plasma FABP concentrations for estimation of myocardial infarct size.
Immunochemically assayed FABP and enzymatically assayed creatine kinase isoenzyme MB (CK-MB) and alpha-hydroxybutyrate dehydrogenase (HBDH) were determined serially in plasma samples from 49 patients with AMI who had been treated with thrombolytic agents within six hours after the onset of AMI. Previously validated circulatory models and a value of 2.6 h-1 for the fractional clearance rate of FABP from plasma were used to calculate cumulative protein release into plasma.
Release of FABP was completed earlier (24-36 h) after AMI than that of CK-MB (50-70 h) and that of HBDH (> 70 h). However, infarct size estimated from the cumulative release of the proteins and expressed as gram equivalents of healthy myocardium per litre of plasma yielded a comparable value of 4-6 for both FABP and the two enzymes.
The data indicate that FABP released from the heart after AMI is quantitatively recovered in plasma and that FABP is a useful biochemical plasma marker for the estimation of myocardial infarct size in humans.
[Show abstract][Hide abstract] ABSTRACT: The release of cytoplasmic heart fatty acid-binding protein (H-FABP) into the plasma of cardiac patients up to 38 hr after the onset of the first clinical symptoms of acute myocardial infarction (AMI) was studied, using a sensitive direct and noncompetitive Enzyme Linked Immunosorbent Assay of the antigen capture type (sandwich ELISA), newly developed for the measurement of small amounts of human H-FABP in plasma samples. Plasma levels of H-FABP were compared with plasma activity levels of the myocardial cytoplasmic enzymes creatine kinase MB (CK-MB) and alpha-hydroxybutyrate dehydrogenase (alpha-HBDH). Upper normal levels of H-FABP (19 micrograms/l), CK-MB (10 U/l) and alpha-HBDH (160 U/l) as determined in plasma from 72 blood donors served as threshold levels. H-FABP levels were significantly elevated above their threshold level within 3 hr after AMI. Peak levels of H-FABP, CK-MB and alpha-HBDH were reached 4.1 +/- 0.9 hr, 8.4 +/- 1.4 hr and 25.0 +/- 9.5 hr (means +/- S.D., n = 10) after acute myocardial infarction, respectively. Serial time curves of the plasma contents of H-FABP reveal that after myocardial infarction H-FABP is released in substantial amounts from human hearts. In 18 out of 22 patients with established AMI the plasma FABP level was at or above the threshold level in blood-samples taken within 3.5 hr after the first onset of symptoms of AMI, while for CK-MB this applied to 9 patients and for alpha-HBDH to 6 patients. These findings suggest that for an early indication of acute myocardial infarction in man cytoplasmic heart fatty acid-binding protein is more suitable than heart type creatine kinase MB and/or alpha-hydroxybutyrate dehydrogenase.
No preview · Article · Nov 1992 · Molecular and Cellular Biochemistry
[Show abstract][Hide abstract] ABSTRACT: A high-yield procedure for the purification of cytoplasmic fatty acid-binding protein from human heart (H-FABP) is described. H-FABP was purified by gel permeation chromatography on a Sephacryl S-200 column followed by anion-exchange chromatography on a Sepharose Q fast-flow column at pH 7.0. At this pH H-FABP binds strongly to the column and can be selectively eluted with a salt gradient. The two-step procedure showed a high degree of reproducibility. On average 50 mg of H-FABP was obtained from 150 g of human heart tissue, which corresponds to a recovery of about 50%. Purity was confirmed by gel electrophoresis and isoelectric focusing. Binding of oleic acid to purified H-FABP, using the Lipidex 1000 assay, revealed a maximal binding of 0.75 +/- 0.01 mol fatty acid/mol protein and a dissociation constant of 0.19 +/- 0.01 microM.
No preview · Article · Oct 1991 · Journal of Chromatography A