Influence of plasma phytanic acid levels in Refsum's disease on the behaviour of the erythrocyte membrane sodium-lithium countertransporter.
BACKGROUND
Abnormal behaviour of the erythrocyte membrane sodium-lithium countertransporter (SLC) is associated with plasma triglyceride concentrations. Refsum's disease is characterized by progressive neurological dysfunction and accumulation of phytanic acid, an isoprenoid fatty acid, in fat-containing tissues.


METHODS
This study explored the effects of plasma phytanic acid on SLC kinetics in nine Caucasian patients with Refsum's disease and in age- and sex-matched Caucasian control subjects.


RESULTS
A dose-dependent association was seen between countertransporter maximal velocity and phytanic acid content of low-density lipoprotein (LDL)-cholesterol (r = -0.61, r = -0.65 respectively; P = 0.05, P = 0.04) and high-density lipoprotein (HDL)-cholesterol (r = -0.81, -0.82 respectively; P = 0.005, P = 0.003). No significant association was seen with the sodium affinity of the transporter (r = -0.44, P = 0.20, for LDL; and -0.43, P = 0.21, for high-density lipoprotein).


CONCLUSIONS
These findings suggest that phytanic acid may alter the behaviour of the sodium-lithium countertransporter.
Wierzbicki
A S
AS
St Thomas Hospital, London, UK. A.Wierzbicki@umds.ac.uk
Hardman
T C
TC
Lumb
P
P
Sankaralingam
A
A
Morrish
Z
Z
Patel
F
F
Sidey
M C
MC
Gibberd
F B
FB
D017920:Antiporters / Q000097:blood*; D016632:Apolipoprotein A-I / Q000097:blood; D016633:Apolipoprotein A-II / Q000097:blood; D001055:Apolipoproteins B / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D007700:Kinetics; D008074:Lipoproteins / Q000097:blood*; D008094:Lithium / Q000097:blood; D008297:Male; D010831:Phytanic Acid / Q000097:blood*; D012016:Reference Values; D012035:Refsum Disease / Q000097:blood*; D012044:Regression Analysis; D012964:Sodium / Q000097:blood; D014280:Triglycerides / Q000097:blood
D017920:Antiporters; D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001055:Apolipoproteins B; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D005230:Fatty Acids, Nonesterified; D008074:Lipoproteins; D014280:Triglycerides; C045885:sodium-lithium countertransporter; D010831:Phytanic Acid; D008094:Lithium; D012964:Sodium