On the interrelationship between hepatic carnitine, fatty acid oxidation, and triglyceride biosynthesis in nephrosis

Free carnitine levels in children with steroid-sensitive nephrotic syndrome

BACKGROUND

Carnitine transports long-chain fatty acids across the inner mitochondrial membrane. Carnitine metabolism is disturbed in some renal diseases, such as chronic renal failure. Previous studies have shown that children had normal serum free carnitine (FC) and total carnitine levels in idiopathic nephrotic syndrome, IgA nephropathy, non-IgA nephropathy and focal segmental glomerulosclerosis. The aim of the present study was to determine FC concentrations in plasma and urine during acute and remission periods of steroid-sensitive nephrotic syndrome (SSNS) and its association with hyperlipidemia.

METHODS

Plasma and urinary FC concentrations were assayed in 15 children with SSNS in acute and in 16 children in remission period. Six of them were followed-up longitudinally in both periods.

RESULTS

Plasma FC concentrations were significantly higher in the acute period of the disease than in the remission period and of the controls. The patients had lower FC levels in the remission period as compared to the controls. Urinary FC concentration was decreased in acute disease period when compared to the remission period and the controls. The FC concentrations in plasma and urine did not correlate with each other. Plasma FC exhibited significant positive correlation with low-density lipoprotein cholesterol, total cholesterol and trygliceride, but negative correlation with high-density lipoprotein cholesterol.

CONCLUSIONS

The present study showed disturbed FC concentration in SSNS. Increased plasma and decreased urinary FC levels in acute disease might be associated with its altered renal handling or some extrarenal factors such as hyperlipidemia.

Effect of the lipoprotein lipase activator NO-1886 on adriamycin-induced nephrotic syndrome in rats

Hyperlipidemia associated with nephrotic syndrome may play a role in the deterioration of renal function. Tsutsumi et al have previously reported that the novel compound NO-1886 increases lipoprotein lipase (LPL) activity, resulting in a reduction of plasma triglycerides and an elevation of high-density lipoprotein (HDL) cholesterol in normal rats. The aim of this study was to ascertain whether NO-1886 suppresses the renal injury by treatment of the hyperlipidemia in an Adriamycin (Kyowa Hakko Kogyo, Tokyo, Japan) induced nephrosis rat model fed a high-protein diet that induced renal dysfunction and tubulointerstitial injury. Administration of Adriamycin caused hyperlipidemia, proteinuria, and edema with ascites in rats in 4 weeks. Furthermore, a combination of Adriamycin and a high-protein diet increased plasma creatinine and blood urea nitrogen (BUN) and decreased plasma albumin. Histologically, in Adriamycin-treated rats, marked interstitial cellular infiltration, tubular lumen dilation, and tubular cast formation in the kidney were observed. NO-1886 decreased plasma triglyceride and increased HDL cholesterol in Adriamycin-induced nephrotic rats. NO-1886 treatment reduced plasma creatinine and BUN levels and increased plasma albumin in Adriamycin-treated rats; it also ameliorated the ascites and proteinuria. Histologically, NO-1886-treated rats showed a quantitatively significant preservation of tubulointerstitial lesions. These data suggest that NO-1886 may have a protective effect against Adriamycin-induced nephrosis with tubulointerstitial nephritis in rats by a modification of the plasma lipid disorder.