Tissue Release of Cardiac Markers: from Physiology to Clinical Applications
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Johannes Mair
Abstract
The early release of cardiac markers is influenced by a variety of factors, the most important influence being their intracellular compartmentation. In contrast to the release of cytosolic proteins, the release of structurally bound proteins requires both a leaky plasma membrane and a dissociation or degradation of the subcellular structure, which is a slower process. Another major impact is the susceptibility to the degradation by cytosolic proteases, such as the calpains. The lysosomes are stable within the first 3–4 hours after onset of ischemia, and, therefore, their enzymes are not involved in the early degradation of structurally bound proteins. Troponin I and troponin T are substrates of μ-calpain. Current experimental as well as clinical results suggest that the molecular mass seems to be of minor importance for the pattern of appearance of myocardial proteins in blood after myocardial infarction. However, within the family of molecules with a certain intracellular compartmentation, the molecular mass is an influence on the appearance in blood, because heavier molecules diffuse at a slower rate, and particularly smaller molecules, such as myoglobin, may enter the vascular system to an even larger extent directly via the microvascular endothelium. The higher the concentration gradient of a marker between the cardiomyocytes and the interstitial space, the faster a parameter will translocate from sarcoplasma to the interstitial space as soon as the plasma membrane permeability is increased. Another influence is local blood and lymphatic flow. Recent experimental studies showed that reperfusion causes a true acceleration of cellular protein leakage by an acute manifestation of plasmalemmal disruptions and not just an enhanced wash out. Marker protein time-courses after myocardial damage are also markedly influenced by their disappearance rate from blood. Most proteins appear to be catabolized in organs with a high metabolic rate, such as liver, pancreas, kidneys, and the reticuloendothelial system. Smaller molecules, such as myoglobin, also pass the glomerular membranes of the kidneys and are reabsorbed and subsequently metabolized in tubular epithelial cells.
Copyright © 1999 by Walter de Gruyter GmbH & Co. KG
Articles in the same Issue
- Author Index
- Contents
- Subject Index
- Strategies for Cardiac Marker Measurement
- Statistical Techniques for Evaluating the Diagnostic Utility of Laboratory Tests
- Magnesium in Disease: a Review with Special Emphasis on the Serum Ionized Magnesium
- Methods for Improving Clinical Trials
- Infrared Analysis of Urinary Stones: a Trial of Automated Identification
- Evaluation of a Direct α-Amylase Assay Using 2-Chloro-4-nitrophenyl-α-D-maltotrioside
- Accurate Platelet Counting in an Insidious Case of Pseudothrombocytopenia
- A New Liquid Homogeneous Assay for HDL Cholesterol Determination Evaluated in Seven Laboratories in Europe and the United States
- Tissue Release of Cardiac Markers: from Physiology to Clinical Applications
- The Specificity of Biochemical Markers of Cardiac Damage: a Problem Solved
- Biochemical Factors Influencing Measurement of Cardiac Troponin I in Serum
- The Sensitivity of Cardiac Markers: an Evidence-based Approach
- Risk Stratification and Therapeutic Decision Making in Patients with Acute Coronary Syndromes the Role of Cardiac Troponin T
- Cardiac Markers: Centralized or Decentralized Testing?
- EC4 European Syllabus for Post-Graduate Training in Clinical Chemistry. Version 2 – 1999
- Plasma Malondialdehyde and Obesity: Is there a Relationship?
- Reference Intervals: Are Interlaboratory Differences Appropriate?
- Lipoprotein Protocols. By J.M. Ordovas, editor
- Tietz Textbook of Clinical Chemistry. By C.A. Burtis and E.R. Ashwood, editors
Articles in the same Issue
- Author Index
- Contents
- Subject Index
- Strategies for Cardiac Marker Measurement
- Statistical Techniques for Evaluating the Diagnostic Utility of Laboratory Tests
- Magnesium in Disease: a Review with Special Emphasis on the Serum Ionized Magnesium
- Methods for Improving Clinical Trials
- Infrared Analysis of Urinary Stones: a Trial of Automated Identification
- Evaluation of a Direct α-Amylase Assay Using 2-Chloro-4-nitrophenyl-α-D-maltotrioside
- Accurate Platelet Counting in an Insidious Case of Pseudothrombocytopenia
- A New Liquid Homogeneous Assay for HDL Cholesterol Determination Evaluated in Seven Laboratories in Europe and the United States
- Tissue Release of Cardiac Markers: from Physiology to Clinical Applications
- The Specificity of Biochemical Markers of Cardiac Damage: a Problem Solved
- Biochemical Factors Influencing Measurement of Cardiac Troponin I in Serum
- The Sensitivity of Cardiac Markers: an Evidence-based Approach
- Risk Stratification and Therapeutic Decision Making in Patients with Acute Coronary Syndromes the Role of Cardiac Troponin T
- Cardiac Markers: Centralized or Decentralized Testing?
- EC4 European Syllabus for Post-Graduate Training in Clinical Chemistry. Version 2 – 1999
- Plasma Malondialdehyde and Obesity: Is there a Relationship?
- Reference Intervals: Are Interlaboratory Differences Appropriate?
- Lipoprotein Protocols. By J.M. Ordovas, editor
- Tietz Textbook of Clinical Chemistry. By C.A. Burtis and E.R. Ashwood, editors
