J.L. Periago

Malnutrition-related polyunsaturated fatty acid changes in plasma lipid fractions of cirrhotic patients

Cirrhotic patients have both impaired liver function and nutritional derangement. In fact, the prevalence of protein-energy malnutrition (PEM) is very high in these patients. The aim of the present study was to elucidate whether the nutritional status in cirrhosis could be an additional factor that would affect levels of plasma lipids. Plasma lipid phosphorus, cholesterol, and triglycerides (TG), and fatty acid profiles in plasma and plasma fractions were determined in 50 healthy subjects and 92 patients with liver cirrhosis. The cirrhotic patients were prospectively included in three groups according to the result of nutritional assessment: group 1 (n = 38), acceptable nutritional status (including well-nourished and mildly malnourished patients); group 2 (n = 29), moderate PEM; and group 3 (n = 25), severe PEM. The main findings of this study were that the decrease in plasma cholesterol and linoleic, dihomo-gamma-linolenic, and arachidonic acid levels of cirrhotic patients was related to the degree of PEM. Cholesteryl esters (CE) appeared to be the most sensitive indicator of lipid changes in cirrhosis. We consider that the role of malnutrition in the changes observed for polyunsaturated fatty acid (PUFA) profiles in plasma lipids of cirrhotic patients may be of major importance, since severe malnourished subjects exhibited the lowest levels of those compounds. Dietary supplementation of both essential fatty acids (EFA) and long-chain PUFA in adequate amounts to the cirrhotic patient might be of importance in the management of the disease.

Effect of dietary (n–9), (n–6) and (n–3) fatty acids on membrane lipid composition and morphology of rat erythrocytes

Studies focused on the intake of different dietary fats have shown changes in membrane lipid composition and, as a result, alterations in membrane physical properties. These changes affect erythrocyte morphology, receptor activity and oxygen transport, among others. Here, we compare the effects of diets exclusively differing in the type of fat (olive oil rich in monounsaturates, sunflower oil rich in n-6 polyunsaturates and fish oil rich in n-3 polyunsaturates) on fatty acid composition of plasma and erythrocyte membranes and erythrocyte morphology under scanning electron microscopy in rats. Monounsaturates are highest in animals fed olive oil diets; as are linoleic and arachidonic acids in sunflower oil-fed animals and n-3 PUFAs in fish oil-fed animals. The lowest levels of arachidonic acid are found in fish oil-fed animals and so are n-3 PUFAs in sunflower oil-fed animals. Our results show that sunflower oil-fed animals present lower discocyte, the major cell shape related to tissue oxygen supply, and higher codocyte percentages than olive oil- and fish oil-fed groups. Echinocyte percentage is higher in fish oil-fed animals with respect to the other two groups. The collective data indicate that olive oil elevates monounsaturates and the number of discocytes, pointing out a possible beneficial aspect of this dietary fat.

Influences of Diet and Postnatal Age on the Lipid Composition of Red Blood Cell Membrane in Newborn Infants

The fatty acid and cholesterol contents of tissue membranes are determinants of their stability and functionality. This study was designed to evaluate the influences of diet and postnatal age on the polyunsaturated fatty acid (PUFA) composition of erythrocyte membrane phospholipid fractions and on the red blood cell membrane cholesterol and phosphorus contents in newborn infants during the 1st month of life. A group of infants was fed on human milk and another group on adapted milk formula. Blood samples were obtained at birth, from cord blood, and at 7 and 30 days of age. Long-chain w6 PUFA declined with advancing age in all membrane phosphoglycerides and sphingomyelin (SM) in those infants fed formula. w6 PUFA also decreased in phosphatidylcholine (PC) and phosphatidylserine (PS) in infants fed human milk and were maintained constant in phosphatidylethanolamine (PE) and SM. w3 PUFA were less affected by postnatal age. PE and SM showed significantly higher percentages of w6 and w3 long-chain PUFA in infants fed human milk than in those fed formula. Membrane cholesterol content increased in all infants from birth to 1 month of life but phosphorus levels were unaffected by diet and postnatal age. These results suggest that diets with a low content of long-chain PUFA, such as adapted cows milk formulas, may induce changes in membrane functionality and that incorporation of PUFA to the diet in amounts similar to those found in human milk should be considered at least in early life.

Effect of dietary olive and sunflower oils on the lipid composition of the aorta and platelets and on blood eicosanoids in rats.

The effects on aortic and platelet fatty acid compositions and on blood levels of prostacyclin and thromboxane A2 of low- and high-fat diets containing olive oil or sunflower oil were studied. For 4 weeks, four groups of weanling rats were fed a basal diet containing 5% or 25% olive oil or sunflower oil. Rats fed olive oil diets showed higher levels of 18:1(n-9) and polyunsaturated fatty acids of the n-3 series and lower percentages of 18:0 and 18:2(n-6) in aortic and platelet phosphatidylcholine and phosphatidylethanolamine than those fed the sunflower oil diets. Arachidonic acid increased in platelet phosphatidylethanolamine and aortic phosphatidylcholine of rats fed the diet containing 5% sunflower oil compared with those fed 5% olive oil. Plasma 6-ketoprostaglandin F1 alpha increased in both groups of animals fed olive oil while these rats also showed the lowest levels of serum thromboxane B2 and plasma cholesterol. Olive oil feeding leads to changes in lipid metabolism of the vascular compartment that could be favorable in the prevention of thrombosis and atherosclerosis.

Effects of dietary fatty acids on lipid metabolism in streptozotocin-induced diabetic rats

We measured the activity of liver delta9- and delta6-desaturases and examined plasma and liver microsome phospholipid fatty acid composition in control and diabetic rats fed a basal diet supplemented with 5% (by weight) olive oil (OO), sunflower oil (SO), or fish oil (FO), respectively. Plasma glucose, cholesterol, triacylglyceride, and phospholipid levels were also measured. An increase in plasma and liver microsome oleic acid and a decrease in arachidonic acid were found in diabetes. In the liver, docosahexaenoic acid levels were higher in diabetic versus control rats. Diabetes increased liver delta9-desaturase in OO-fed rats and did not modify delta6-desaturase activity in OO- or SO-fed rats. Both enzymatic activities were decreased in diabetic rats fed the FO diet. As a main conclusion, it appears that diet-induced alterations in membrane composition provide a mechanism for improving the diabetic condition in animals and overcoming the effect of insulin deficiency on desaturase activities. Plasma cholesterol was not modified either by diabetes or by diet. In diabetes, OO-fed rats showed the lowest levels of triglycerides. Plasma phospholipids were significantly higher in OO-fed versus FO-fed rats. These findings suggest that OO contributes to a better control of the hypertriglyceridemia accompanying diabetes as compared with the other two diets in this rat model.

Modulation of hepatic and intestinal glutathione S-transferases and other antioxidant enzymes by dietary lipids in streptozotocin diabetic rats.

Antioxidant enzymes in liver and small intestine were investigated using control and streptozotocin diabetic rats fed diets with 5% olive, sunflower or fish oil for five weeks. In liver, Glutathione Peroxidase and Superoxide Dismutase decreased and in intestine Glutathione-S-transferase (GST) increased by diabetes. In isolated jejunum and ileum, this increase in GST activity was due to an increase in GST-alpha and -mu isoenzymes in jejunum and GST-alpha, mu and -pi in ileum. Since GST plays an important role in protecting tissues from oxidative damage, our results highlight the role of the intestine against free radicals in physiological or pathological situations.

Effects of dietary polyunsaturated fatty acids and nucleotides on tissue fatty acid profiles of rats with carbon tetrachloride-induced liver damage

The deficiency of polyunsaturated fatty acids (PUFA) that occurs in plasma of patients with liver cirrhosis has been assessed in rats with severe steatosis and mild liver necrosis induced by repeated administration of low doses of carbon tetrachloride (CCl(4)). The contribution of both dietary (n-3) long-chain PUFA and nucleotides to the recovery of the altered fatty acid profiles of tissue lipids of these rats has also been studied. Two groups of rats were used. The first was intraperitoneally injected 0.15 ml of a 10% (v/v) CCl(4)solution in paraffin per 100 g of body weight, three times a week for 9 weeks; the second received paraffin alone. After the treatment, six rats of each group were killed. Afterwards, the remaining controls were fed a semipurified diet (SPD) for 3 weeks, and the remaining rats in the CCl(4)group were divided into three new groups: the first was fed the SP diet; the second was fed the SP diet supplemented with 1% (n-3) polyunsaturated fatty acids (PUFA diet); and the third was fed the SP diet supplemented with 250 mg nucleotides per 100 g diet (NT diet). Fatty acids of plasma, erythrocyte membranes and liver microsomes were analyzed. Decreases in linoleic and arachidonic acids in both total plasma lipids and liver microsomal phospholipids were the main findings due to CCl(4)treatment. The rats that received CCl(4)and the PUFA diet showed the lowest levels of (n-6) PUFA and the highest levels of (n-3) PUFA in liver microsomal phospholipids, as well as a significant increase of (n-3) PUFAs in total plasma lipids. The animals that received the NT diet showed no signs of fatty infiltration and exhibited the highest levels of (n-6) PUFAs in liver microsomal phospholipids. These results show that CCl(4)affects fatty acid metabolism which is accordingly reflected in altered tissue fatty acid profiles, and that balanced diets containing PUFA and nucleotides are important for the recovery of the damaged liver in rats.

Serum and Urine Amino Acid Patterns during the First Month of Life in Small-for-Date Infants

Prenatal nutrition is impaired in small-for-gestational-age infants. Serum amino acids may show some biochemical features related to the nutritional state of these children. We have carried out a study on serum and urine amino acids in 12 small-for-date infants (SFD) and 14 healthy newborns from birth to 1 month of life. SFD infants showed a high serum level of alanine and decreased concentrations of branched chain amino acids, aspartate, cystine and tryptophan at birth. The results are compatible with a protein malnutrition state. Levels of serum amino acids in SFD infants showed no differences in relation to normal infants after 1 month of rehabilitation with a diet consisting of an adapted milk formula.

Differences in the Serum Amino Acid Pattern of Injured and Infected Children Promoted by Two Parenteral Nutrition Solutions

The effects of two parenteral nutrition (PN) amino acid solutions (FreAmine II and F080) on the serum amino acid levels of 51 children, 27 affected by multiple trauma and 24 by bacterial sepsis, and aged from 1 month to 12 years, were studied. Serum amino acids were determined on day 1 immediately before administrating PN, and on day 5 during PN. Trauma patients on F080 exhibited higher levels of alanine, aspartate, asparagine, leucine, isoleucine, valine, total branched-chain amino acids (BCAA) and total essential amino acids than those on FreAmine II; in contrast septic children showed similar levels of serum amino acids on both PN solutions. BCAA were lower in septics than in trauma patients, probably as a consequence of an increased utilization of these amino acids in sepsis because of the higher organ protein synthesis typical of this situation. The phenylalanine/tyrosine ratio was found elevated both in septic and trauma children, but it decreased after PN in the latter when using an enriched BCAA solution. Utilization of this solution, partly corrects the metabolic disturbances induced by stress, but the metabolical responses induced either by sepsis or trauma are partially different which may have important implications for patient care.