Abstract 2991

Poster Board II-967

Background.

The natural function of ACTH in blood is not well defined. However elevated plasma level was reported in patients with chronic inflammation, suggesting as one of inflammatory markers. Erythrocytes possess membrane-bound acetylcholinesterase (AChE) while plasma contains a less specific cholinesterase (ChE). We reported at a previous meeting [Blood 2008, 112(11) Abst #3849] that AChE activity of RBC-derived microparticles (RMP) is 6 times higher than those in PMP. In this study we measured plasma ACTH levels in several groups and encountered unexpectedly high plasma ChE activities in patients with TIA and other thrombosis.

Methods.
(i) Patient population.

A series of n=108 consenting patients were recruited sequentially having various disorders For purpose of analysis, they were divided in 2 main groups: n=53 with thrombosis (TBS), F/M 27/26; and n=55 non-TBS, F/M 24/31. Thrombosis group consists of venous and arterial thrombosis including those with TIA. Non TBS group consists of anemias, thrombocytopenias including ITP, MDS.

(ii) Assay

was essentially by Ellman's method. In our system, milli-absorbance units/min (mA/min) x 0.065 = umols substrate cleaved/min. Values reported here are in unitsof mA/min per mL plasma. Normal controls (NC, n=14) had a cutoff of 3000 mA/min per mL plasma, = mean +2SD.

(iii) Sample handling.

Platelet-poor plasma (PPP) was prepared by centrifuging 10 min at 1800 xg, then frozen in aliquots. For assay, it was diluted 1:20 with saline, then 5 uL and 10 uL were used in 96-well microtiter plate.

Results:

(i) Significantly higher ChE activity was observed in thrombosis (TBS) patients compared to non-TBS. Mean value ±SD in TBS was 2928 ±773, and in Non-TBS was 1897 ±713 (units as above). This difference was significant, p<0.001. (ii) When analyzed elevated levels of ACTH above 2SD of normal controls (n=26) between 2 groups, the TBS group had elevated ChE (>3000) in 30% of patients, while the Non-TBS had elevated ChE in 7.8%. (iii) Further analysis among thrombosis group revealed that the subgroup with neurological TBS (TIA, minor strokes) had the most consistent elevations of ACTH; 10 of15 with TIA group (66%) had ChE activities >3000.

Summary/ Discussion.

Although ChE and AChE in blood has long been studied, to our knowledge, this is the first report to show a relation between plasma ChE and thrombosis. Its elevation is very pronounce in thrombosis of the CNS, manifesting as TIA. Further study is warranted to elucidate how ChE is related to AChE of the CNS and on red cells.

Disclosures:

No relevant conflicts of interest to declare.

Topics:
butyrylcholinesterase, cholinesterases, pseudocholinesterase, thrombosis, transient ischemic attack, acetylcholinesterase, corticotropin, megestrol acetate, migraine disorders, mitral atresia

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2009 by The American Society of Hematology
2009
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