HES (hydroxyethyl starch)
Information on HES February 19, 2001 - (Reason: positive doping cases at the World Ski Championships in Lahti, Finland)
For the first time since April 1, 2000, the IOC Medical Commission has banned the use of plasma expanders such as HES (hydroxyethyl starch)
Plasma expanders are substances that increase total blood volume (volume expansion). The following four groups are used as plasma expanders:
- Human albumin
- Dextrans
- Hydroxyethyl starch
- Gelatin preparations
Dextrans are polysaccharides composed of glucose molecules as their basic building blocks. Modified starch, produced by reacting the basic glucose molecules with hydroxyethyl groups (“ethanol”), is also used as a plasma expander (Fig. 1). This product is marketed under the name hydroxyethyl starch (HES).
Plasma expanders are medically used in cases of peripheral circulatory failure (shock, collapse) and are injected into the bloodstream. The cause of this is usually persistent hypotension (low blood pressure), which arises as a result of an imbalance between the circulating blood volume and the capacity of the vascular space.
The injection of electrolyte solutions (crystalloid volume expanders) has the disadvantage that they leave the bloodstream relatively quickly and thus have a short-lived effect. In principle, electrolyte solutions should only be used in cases of electrolyte imbalance.
Significance as a Doping Agent
Plasma expanders were placed on the IOC’s prohibited list after it became known that athletes were using them to lower their hematocrit levels (as a countermeasure to EPO doping). Another use is to compensate for fluid loss during endurance exercise.
Side effects
Side effects following HES infusion are described as follows (product information):
- Skin reactions: severe itching that is difficult to treat
- Rapid heartbeat (tachycardia), drop in blood pressure, dizziness, nausea, vomiting
- Shock, asthma-like conditions (bronchospasm)
- Respiratory and circulatory arrest
In the event of these adverse reactions, the infusion must be stopped immediately and the physician must initiate standard emergency measures.
Evidence
The following publications on the detection of HES were published by the Institute of Biochemistry at the German Sport University Cologne:
Dtsch. Z. Sportmed. 52, 11 (2001) 316-320
Nachweis des Plasmavolumenexpanders Hydroxyethlstärke in Humanurin.
Thevis M, Opfermann G, Schänzer W
German Sport University Cologne, Institute of Biochemistry, Carl-Diem-Weg 6, 50933 Cologne, Germany m.thevis@biochem.dshs-koeln.de
Since January 2000, plasma volume expanders such as hydroxyethyl starch (HES) have been banned in sports by the International Olympic Committee. Therapeutically, these are used to treat hypovolemic shock and to promote blood circulation; in sports, however, they are used to unphysiologically increase intravenous body fluid volume and to lower hematocrit and hemoglobin levels.
The detection of HES administration in doping analysis is performed using two methods based on the degradation of the polymer and the subsequent derivatization of the monomers. In a rapid screening procedure, the per-trimethylsilyl derivatives of glucose and hydroxyethylated glucose (HEG) are generated and detected using gas chromatography and mass spectrometry.
In this process, the endogenously non-occurring 2- and 3-HEG are identified using the characteristic fragment ions m/z 235, 248, and 261. The detection of a polysaccharide structure in the metabolites of hydroxyethyl starch is subsequently confirmed in a confirmatory method through the formation of partially methylated alditol acetates (PMAAs).
To this end, the polymer is methylated at all free hydroxyl groups, hydrolyzed, reduced to alditols, and subsequently acetylated at the remaining hydroxyl groups. The resulting products were identified using mass spectrometry. Using these methods, six athletes were found guilty of doping at the 2001 Nordic World Ski Championships in Lahti (Finland).
J Chromatogr B Biomed Sci Appl 2000 Jul 21;744(2):345-50
Detection of the plasma volume expander hydroxyethyl starch in human urine
Thevis M, Opfermann G, Schänzer W
Institute of Biochemistry, German Sports University Cologne, Germany, m.thevis@biochem.dshs-koeln.de
The plasma volume expander hydroxyethyl starch (HES) is usually administered in cases of hypovolemic shock, but in 1998 the press reported its misuse in endurance sports. Since January 2000, it has been placed on the International Olympic Committee’s (IOC) list of prohibited substances, and its misuse is subject to sanctions through doping controls. Therefore, a rapid method enabling the screening for HES in human urine was developed, which can be easily adopted by IOC laboratories to analyze routine urine samples for this substance. Urine samples obtained from patients treated with HES, blank urine specimens, and reference standards were hydrolyzed with hydrochloric acid, and without any further purification of the resulting monosaccharides, their per-timethylsilylated derivatives were prepared. Using gas chromatography-mass spectrometry, the products were separated, and the alpha- and beta-isomers of glucose, as well as 2-, 3-, and 6-hydroxyethyl glucose derivatives, were identified. Typical ion traces of 2- and 3-substituted glucose (m/z 248, m/z 261, and m/z 235, m/z 248, respectively) support the rapid determination of the substances, whose electron impact mass spectra are presented and discussed.
J Mass Spectrom 2000 Jan;35(1):77-84
Mass spectrometry of partially methylated alditol acetates derived from hydroxyethyl starch.
Thevis M, Opfermann G, Schänzer W
German Sport University Cologne, Institute of Biochemistry, Carl-Diem-Weg 6, 50933 Cologne, Germany m.thevis@biochem.dshs-koeln.de
The degradation and derivatization of hydroxyethyl starch to partially methylated alditol acetates (PMAAs) allows its detection by gas chromatography/mass spectrometry. The derivatization was performed by permethylation of the carbohydrate, hydrolysis of the permethylated polysaccharide, reduction of the resulting monosaccharides to alditoles, and finally acetylation. A close similarity in the fragmentation of the obtained PMAAs was observed in both electron ionization (EI) and chemical ionization (CI) mass spectra due to the comparable structures of the derivatives. CI measurements allowed the identification of introduced hydroxyethyl groups in the glucose residues through the detection of [M(+)+1]-60 signals. Investigations into the EI fragmentation patterns allowed for the reliable identification of monohydroxyethyl monosaccharides and the differentiation between the possible positions (C-2, C-3, and C-6) of the substituted hydroxyethyl groups. Proposed origins of the main fragment ions are presented.
German Sport University Cologne, Institute of Biochemistry, last updated December 16, 2001