Omega-3 fatty acids improve postprandial lipaemia in patients with nephrotic range proteinuria.
BACKGROUND
Patients with nephrotic range proteinuria have a marked increase in the risk of cardiovascular disease. Qualitative and quantitative changes in lipids and lipoproteins contribute to this increased risk with an abundance of atherogenic triglyceride (TG) rich apolipoprotein B containing lipoproteins. TG rich lipoproteins predominate postprandially and are associated with increased risk of coronary heart disease (CHD). Omega-3 fatty acids derived from fish oils have been shown to have beneficial effects on lipids and lipoproteins in patients without proteinuria.


METHODS
17 patients with nephrotic range proteinuria and 17 age and sex matched controls were studied. Postprandial lipaemia was assessed in patients and controls, before and after 8 weeks treatment with 4 g daily of omega-3 fatty acids (Omacor). A standard fat load (90 g) was administered and blood sampling was performed in the fasting state and at 2, 4, 6 and 8h after the fat load. Chylomicrons and VLDL(1) density fraction was isolated from plasma by density ultracentrifugation. Postprandial chylomicron and VLDL(1) triglyceride concentrations were measured and quantified using the incremental area under the curve (AUC) method.


RESULTS
Baseline postprandial chylomicron TG AUC was greater in patients compared with controls: median 18.5 mmol/lh (interquartile range 8.9-32.6) vs 9.3 mmol/lh (4.8-14.4) p=0.05. Following treatment patient chylomicron AUC fell [mean reduction 6.8 mmol/lh (95% CI 0.1-13.6) p=0.05]. No significant reduction in chylomicron AUC was observed in the controls [mean reduction 3.9 mmol/lh (95% CI -3.6 to 11.5)]. As a result, following 8 weeks treatment with omega-3 fatty acids, patient and control chylomicron AUC were no longer significantly different [patients 13.5 mmol/lh (7.4-22.9), controls 7.2 mmol/lh (4.6-14.5) both median and IQR, p=nsd]. VLDL(1) TG AUC did not differ at baseline between patients and controls. Furthermore, there was no significant effect on VLDL(1) AUC following treatment in either group.


CONCLUSIONS
We have shown that there is an excess of postprandial chylomicron density fraction in patients with nephrotic range proteinuria, which is reduced by treatment with omega-3 fatty acids. We suggest that this would be an ideal therapy in combination with statins for this high risk group of patients.
Bell
Samira
S
Renal Unit, Glasgow Royal Infirmary, Glasgow, United Kingdom. samira.bell@nhs.net
Cooney
Josephine
J
Packard
Christopher J
CJ
Caslake
Muriel
M
Deighan
Christopher J
CJ
D000368:Aged; D019540:Area Under Curve; D002318:Cardiovascular Diseases / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D005260:Female; D005395:Fish Oils; D006801:Humans; D006949:Hyperlipidemias / Q000175:diagnosis*; D007674:Kidney Diseases / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D008074:Lipoproteins / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D011507:Proteinuria / Q000628:therapy*; D012306:Risk
D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D008055:Lipids; D008074:Lipoproteins