Serum Carnitine Levels Research Articles

450 SERIAL MEASUREMENTS OF SERUM CARNITINE IN REYE'S SYNDROME(RS)

Serum carnitine was determined in 3 children with stage III RS and 1 child with stage II RS during the acute phase of their illness. Normal levels(.037 ± .014 μmol/ml) occurred on admission followed by a 1.5-2.5 fold elevation(.072,.086 μmol/ml) 8-24 hours later. Serum carnitine in 2 children with stage III RS peaked just prior to or shortly after exchange transfusion. One child with stage II RS exhibited normal carnitine values in the first 4 days, as did one child with stage III RS. Forty children from 2-15 years with no liver or muscle disease served as controls. A 6-year-old girl with acute viral hepatitis (non A,non B) demonstrated normal-subnormal levels(.042-.004 μmol/ml) during the acute phase of her illness (>2 SD below the mean). Elevation of lactic acid (normal 20 mg/dl), blood ammonia (up to 100 μg/dl) AST, ALT(up to 35 u/ml), CPK(50 Iu/1) and stage of coma (Hutten-locher staging) did not correlate with serum carnitine values. All RS patients received similar intensive medical support and ICP monitors. The RS children survived and serum carnitine levels returned to normal on recovery. Elucidation of the contribution of carnitine to the pathogenesis of generalized mitochondrial dysfunction in RS remains to be determined. Further studies are in progress to define the role of carnitine aside from its previously described function for transport of acyl long chain fatty acids across outer and inner mitochondrial membranes.

The relationship between serum carnitine levels and the nutritional status of patients with schistosomiasis

Serum carnitine levels were investigated in a group of normal adults and two groups of patients with active schistosomiasis who also showed signs of malnutrition and vitamin deficiency. The first group consisted of 16 patients with Schistosoma mansoni and/or Schistosoma haematobium infection. They received an adequate diet supplemented with vitamin and iron therapy and received no treatment for their parasitic infection till their hemoglobin levels were restored to normal. The second group consisted of 12 patients with schistosomiasis as well as intestinal polyposis. They received the same diet as the first group but because of their poor condition were immediately treated for parasitic infection. Results showed that both groups of patients had subnormal levels of serum carnitine with the polyps patients (Group II) having a significantly lower level than patients with simple schistosomiasis (Group I). After nutritional repletion a significant increase was observed in the carnitine levels of most patients in group I indicating a relationship between the nutritional status of the patients and their serum camitine levels. The patients with polyps also showed considerably increased camitine levels after treatment and dietary repletion. The usefulness of serum camitine measurement as an index of protein malnutrition in man is discussed.

Lipid storage myopathy with normal carnitine levels

A 28-year-old female, who showed a floppy baby syndrome during early infancy, had a non-progressive proximal muscle weakness with easy fatiguability since childhood. Two muscle specimens biopsied at the age of 28 years revealed myriads of 1–3-μm wide abnormal spaces containing neutral fat in type I and type II fibers. Both biopsies demonstrated a type I fiber preponderance. Electron microscopy demonstrated lipid excess and normal mitochondria by simple inspection. The mitochondrial area and sarcotubular membrane profile concentration in morphometry of longitudinal sections were also normal. Cross-sections, however, revealed a slight decrease of the individual mitochondrial size and of the sarcotubular membrane profile concentration. Serum and muscle carnitine levels and the muscle carnitine palmityltransferase level were all within normal range. Besides carnitine deficiency other biochemical defects can occur in lipid storage myopathy, which represents a syndrome rather than a unique disease entity.

Carnitine levels in human serum in health and disease

The level of carnitine in serum was examined in a control group and in different patient groups. A radiometric assay of carnitine with carnitine acetyltransferase and radioactively labeled acetyl-CoA was used. By the addition of dithionitrobenzoic acid (DTNB) to the incubation mixture to trap the CoASH released, the formation of radioactive acetylcarnitine was proportional to the carnitine concentration over a wide range. Carnitine was extracted from plasma after ethanol addition and the recovery of [ Me- 3H] carnitine added to serum was 102%. The serum level of carnitine was reduced in patients with myotonia congenita, Crohn's disease in some patients with malabsorption and in cases of anorexia nervosa. During hemodialysis the carnitine concentration was reduced to 25% of the value occurring before dialysis. Normal levels of carnitine were found in ulcerative colitis patients, most patients with malabsorption, in liver cirrhosis, in right-sided heart failure with liver stasis, in juvenile and adult onset diabetes, and in cardiomyopathies. Two patients with progressive cardiac failure with icterus and oliguria showed an eight-fold increase in serum carnitine levels.