Glycated calmodulin from platelets as an index of glycemic control

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 39; no. 5; pp. 815 - 819
• Main Authors: Muruganandam, A, Romsa, GJ, Thibert, RJ, Cheung, RM, Draisey, TF, Mutus, B
• Format: Journal Article
• Language: English
• Published: Washington, DC Am Assoc Clin Chem 01.05.1993; American Association for Clinical Chemistry
• Subjects: Adolescent; Adult; Biological and medical sciences; Blood Glucose - metabolism; Blood Platelets - metabolism; Calmodulin - blood; Child; Chromatography, Affinity; Diabetes Mellitus, Type 1 - blood; Endocrinology; Enzyme-Linked Immunosorbent Assay; Fructosamine; Glycated Hemoglobin A - metabolism; Glycosylation; Hexosamines - blood; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Endocrinopathy; Human; Correlation; Diabetes mellitus; Biological marker; Serum protein; Assay; Binding protein; Platelet; Affinity chromatography; Laboratory investigations; Clinical biology; ELISA assay; Calmodulin; Glycemia
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1093/clinchem/39.5.815

In an effort to test whether a significant fraction of calmodulin would become glycated within the life span of the platelet (10-14 days), we monitored the kinetics of calmodulin glycation in vitro. Under the conditions we used, the fraction of glycated calmodulin reached a maximum (approximately 21%) within 10 days. We then extended the studies to human subjects. The intraplatelet concentrations of calmodulin and glycated calmodulin from age-matched type I diabetic subjects were monitored by a combination of m-aminophenylboronate affinity chromatography and enzyme-linked immunosorbent assay. The results indicate that the concentrations of total intraplatelet calmodulin (nonglycated plus glycated) were not dependent on the glycemic state of the subjects. Data from control and diabetic subjects showed a poor correlation between the concentrations of glycohemoglobin and of glycated calmodulin. However, a better correlation was obtained when glycated calmodulin concentrations were compared with those of serum fructosamine. The fraction of glycated calmodulin in the control population (7.71% +/- 0.75%) was significantly (P < 0.05) different from that of the diabetic population (21.6% +/- 1.26%). Given that the clinical role of the fructosamine assay remains controversial, estimation of glycated calmodulin in platelets might be useful as a short time-window index of glycemic control.