Erythrocyte Plasmalogens

The most logical material for the analysis of PUFA and plasmalogens are the erythrocytes. Fatty acids can also be quantitated in plasma. The plasmalogens are also easily detectable in homogenates of cultured fibroblasts and may add to the definitive diagnosis of patients with a generalised or isolated peroxisomal dysfunction. 

A so-called plasmalogen extract. This is a pool of extracted and derivatised erythrocyte samples. It is used solely to check for the detector response of the plasmalogens, thereby identifying active spots in the injection system. 

Fig. 3.3.2 Gas chromatography trace of essential fatty acid methyl esters and plasmalogen di-methylacetals in control erythrocytes. The plasmalogens are eluted adjacent to their corresponding fatty acid methyl esters...

Increased plasmalogen levels have not been observed. Erroneously low red cell levels can be encountered when the transmethylation process has not been completed. Breaking the ether lipid bond of the plasmalogens requires more energy than hydrolysis of the fatty acid esters. Evaluation of the plasmalogen levels should not be done after a blood transfusion. Donor erythrocytes will be present for up to 120 days following a transfusion. 

Patients with Refsum disease may have extremely high phytanic acid levels, up to 1500 pmol/1, whereas pristanic acid is low (< 1 pmol/1) as a consequence of the phytanoyl-CoA hydroxylase deficiency. Less pronounced phytanic acid elevations will be observed in RCDP type 1 patients, which applies to both the classical form as well as the variant forms. Values may range from 200 to 900 pmol/1, somewhat depending on age. There is some discussion on the time of onset of phytanic acid accumulation in the classical neonatal RCDP-patients. Normal plasma phytanic acid levels (0.7-5.8 pmol/1) were recorded in the authors laboratory in patients aged less than 1 week. Two- to three-week-old RCDP patients had increased phytanic acid levels of 9.1 -13.2 pmol/1. Classical patients invariably had undetectable plasmalogen levels of the erythrocytes at any age. 

Human Erythrocyte Phosphoglycerides. I. Quantitation of Plasmalogens, Fatty Acids and Fatty Glycerides Biochim. et Biophys. Acta 60 80-89 (1962) Biol. Abstr. 40 21989... 

In the meantime plasmalogen levels should be measured in erythrocytes, using the method described by Bjorkhem et al [18] or another established method like the one described by Vreken et al. [19]. If plasmalogens are decreased, a peroxisome biogenesis defect is established. If plasmalogens are normal, however, it probably is a POD but it may also be a peroxisome biogenesis defect simply because in milder PDB forms, notably infantile Refsum disease patients, plasmalogens may be completely normal. 

Very-long-chain fatty acids (VLCFA), trihydroxycholestanoic acid (THCA), phytanic acid and pristanic acid can all be measured in plasma/serum (> 1 ml). From the same blood sample erythrocytes, platelets and/or leukocytes can be prepared for determination of plasmalogens and dihydroxyacetone-phosphate acyltransferase (DHAPAT), respectively. 

Plasmalogens Erythrocytes from Room tempera- None... 

Farquhar, J. W. Human erythrocyte phosphoglycerides. I. Quantification of plasmalogens, fatty acids and fatty aldehydes. Biochim. biophys. Acta (Amst.) 60, 80 (1962). 

It is of considerable interest that human erythrocyte phosphoglycerides have a similar distribution of plasmalogens and fatty acids to that of platelets (Farquhar, 1962). Although the fatty add composition of PS in the red cell resembles that of the platelet, there is about twice as much PS in the erythrocyte. This may account for the marked clot-promoting effects of lipids and lipoproteins derived from red cells after damage or hemolysis (O Brien, 1959a Shinowara, 1951, 1957, 1961). 

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