Roles of Innate Instability Characteristic of Hemoglobin Molecule to Hemichrome and Subsequent Heinz Body Formation within Normal Human Erythrocytes

Author(s): Yoshiaki Sugawara, Yoko Abe, Ikumi Ohgushi, Eriko Ueno and Fumio Shimamoto

Heinz bodies are intraerythrocytic inclusions of hemichrome that result from oxidized or denatured hemoglobin. In normal human erythrocytes, Heinz bodies are typically formed in aged red cells and involved in recognitionmechanisms for the removal of non-functional erythrocytes fromthe circulation. In this review, given the hypothesis that hemichrome formation is an innate characteristic of physiologically normal hemoglobinmolecules, two studies deserve emphasis. One study assessed hemichrome formation of human adult hemoglobin (HbO2 A) by spectrophotometry; the other study evaluated possible hemichrome formation and subsequent Heinz body clustering in erythrocytes. In the latter study, aliquots of freshly drawn venous blood fromhealthy donorswere subjected to mild heating at each desired temperature over 37oC for 30 min. Heinz bodies were then visualized by exposing blood smears to acetylphenylhydrazine and stained with crystal violet. The changes that occurred within erythrocytes were followed by light microscopy under oil-immersion. The number of Heinz bodies formed in red cells increased with increasing temperature. These findings combined with the results obtained by the former study that HbO2 A prepared from healthy donors possesses a propensity of instability to hemichrome even in close to physiological temperature and pH suggest that Hb molecules delicately control the fate of red blood corpuscles in the removal of non-functional erythrocytes from the circulation by causing hemichrome formation and subsequent Heinz body clustering.

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