Generality
Aldolase is an enzyme normally found in many tissues and organs (skeletal muscle, myocardium, liver and brain). In these districts, it participates in the production of energy from glucose .
The circulating amount of aldolase can be detected with a blood test. An increase in enzyme values is indicative of some diseases related to skeletal muscle, including Duchenne muscular dystrophy and polymyositis. The aldolase can also increase during myocardial infarction and during some chronic liver diseases.
What's this
The aldolase is a ubiquitous enzyme (that is, it is found everywhere in the body). However, it is found in high concentrations especially in muscle tissue, in the form of three different isoforms (aldolase A, B and C).
The aldolase is involved in glycolysis, ie in the utilization of glucose as an energy substrate.
Biological role
The aldolase ( ALD or ALS ) is a glycolytic enzyme that catalyzes the transformation of fructose-1-6-diphosphate into two molecules of triosis (glyceraldehyde-3-phosphate and dihydroxyacetone phosphate) in the fourth reaction of glycolysis (energy-producing metabolic pathway) starting from glucose).
Also from the biochemical point of view, aldolase activity is important in fructose metabolism.
The aldolase has a ubiquitous distribution, which means that it is distributed in all the tissues of the body, especially where glycolysis provides the greatest response to energy needs, therefore in skeletal muscle, in the liver and in the brain. Since it abounds particularly at the level of these tissues, in the presence of an aldolase high in the blood, the presence of cellular (cytolysis) hepatic or muscular damage is probable.
The aldolase is formed by two subunits; four isoforms are recognized consisting of three distinct subunits (A, B and C): the A4 molecular form prevails in skeletal muscle, B4 in the liver and C4 in the brain and in other tissues.
Why do you measure
The aldolase concentrations in the blood maintain a certain diagnostic importance in muscular diseases such as progressive dystrophies, and in the monitoring of the therapy undertaken.
Its determination can be recommended in the rare cases of suspected myositis with normal CK. The main utility of aldolase, in particular of the CK / aldolase ratio, appears to be the differentiation between myopathy and muscular atrophy.
Normal values
The reference values for aldolase are in the range 0.5-3.0 IU / L.
Note : the reference interval of the exam can change according to age, sex and instrumentation used in the analysis laboratory. For this reason, it is preferable to consult the ranges listed directly on the report. It should also be remembered that the results of the analyzes must be assessed as a whole by the general practitioner who knows the patient's medical history.
High Aldolase - Causes
Aldolase values are increased in case of Duchenne muscular dystrophy, in dermatomyositis, in polymyositis, but not in neurogenic atrophies (such as multiple sclerosis or myasthenia gravis).
The aldolase may increase in the course of chronic and especially acute liver diseases (correlated by a parallel elevation of ALT), while it remains unchanged in biliary tract diseases.
High aldolases are also found in the presence of:
- Muscular trauma,
- Myocardial infarction,
- Some tumors (stomach, lung, breast, myeloblastic leukemia),
- Hemorrhagic pancreatitis,
- Hemolytic diseases
- Gangrene.
Hepatotoxic drugs, helminthians and insecticides can cause increased aldolase levels.
Low Aldolase - Causes
Low aldolase values are not usually associated with medical problems and / or pathological consequences. Therefore, these are not considered clinically relevant.
How to measure it
The aldolase test is performed after a normal peripheral blood test, performed on an empty stomach.
Preparation
Before undergoing the useful extraction to determine aldolase, it is necessary to observe a fast of at least 8 hours. During this period, a small amount of water can be taken. Furthermore, before the exam, you must be in an upright position for at least 30 minutes.
The aldolase analysis can be altered after taking some drugs, including pesticides and drugs that have some hepatotoxicity as possible side effects. Even intense and recent physical and muscular activity can influence the outcome of the investigation.
Interpretation of Results
The aldolase examination was required especially in the past, for the diagnosis and monitoring of some diseases related to skeletal muscle.
Currently, this analysis has been largely replaced by the evaluation of markers of muscle damage, such as CK (creatine kinase). However, his determination may still be useful:
- In cases of suspected myositis with normal CK;
- In the evaluation of cellular damage in myopathies (muscular dystrophies, necrotizing myositis, etc.);
- In supporting the diagnostic hypothesis related to muscle diseases, including Duchenne muscular dystrophy and polymyositis.
