Role of Oral Nutritional Supplements Enriched with ß-Hydroxy-ß-Methylbutyrate in Maintaining Muscle Function and Improving Clinical Outcomes in Various Clinical Settings.

Aging and disease-related malnutrition are well associated with loss of muscle mass and function. Muscle mass loss may lead to increased health complications and associated increase in health care costs, especially in hospitalized individuals. High protein oral nutritional supplements enriched with ß-hydroxy-ß-methylbutyrate (HP-ONS+HMB) have been suggested to provide benefits such as improving body composition, maintaining muscle mass and function and even decreasing mortality rates. The present review aimed to examine current evidence on the effect of HP-ONS+HMB on muscle-related clinical outcomes both in community and peri-hospitalization patients. Overall, current evidence suggests that therapeutic nutrition such as HP-ONS+HMB seems to be a promising tool to mitigate the decline in muscle mass and preserve muscle function, especially during hospital rehabilitation and recovery.

Quantification of ß-hydroxymethylbutyrate and leucine by ultrahigh performance liquid chromatography tandem mass spectrometry at different situations and stages of a rodent life.

The main objective of this work was to develop a method to measure Leucine (Leu) and ß-hydroxymethylbutyrate (HMB) at basal levels in serum, urine, milk and brain microdialysates in rats. Ultrahigh performance liquid chromatography-electrospray-tandem mass spectrometry (UHPLC-ESI-MS/MS) was used as analytical technique. The sample treatment was simple and consisted of dilution with methanol and centrifugation for serum and urine, dilution with water and filtration with an Amicon filter for milk, and treatment with formic acid with no further dilution for microdialyzates. The procedures for sampling and the UHPLC-MS/MS parameters were accurately optimized to achieve the highest recoveries and to enhance the analytical characteristics of the method. For chromatographic separation, an Acquity UPLC BEH Amide column using acetonitrile-water gradient with formic acid as additive was used. The total run time was 4min. The analytical characteristics (accuracy, selectivity and sensitivity) of the proposed method were evaluated. The limits of detection (LODs) obtained ranged from 0.4 to 7ngmL(-1) and the limits of quantification (LOQs) from 1 to 22ngmL(-1). Precision, expressed as relative standard deviation (% RSD), was lower than 15% in all cases, and the determination coefficient (R(2)) was equal or higher than 99.0% with a residual deviation for each calibration point lower than ±25%. Mean recoveries were between 85 and 115%. The method was successfully applied to these matrices being able to detect significant differences between physiological situations, strains and stages of life.

Intestinal toxicity induced by 5-fluorouracil in pigs: a new preclinical model.

BACKGROUND: The goal of this study was to develop an animal model of intestinal injury induced by 5-fluorouracil (5-FU) in pigs. METHODS: Six domestic pigs were used as control (healthy group) and another 6 malnourished pigs orally received 5-FU (treated group). After 4 weeks of treatment, pigs were sacrificed and jejunum, ileum and colon were isolated for histological, immunological and biochemical analyses. RESULTS: 5-FU caused a decrease in the intestinal mass. Disaccharidase, and phosphate alkaline activities, and glutathione redox cycle were disrupted by 5-FU. Histopathological alterations in the crypts and villous were greater in the small intestine than in the colon. 5-FU decreased the number of peripheral and intestinal leukocytes, promoting an increase in T-cytotoxic cells and a decrease in T-helper and B cells. CONCLUSION: This pig model of intestinal dysfunction closely mimics the common side effects of cancer chemotherapy in humans, and provides a useful tool for evaluating novel antimucotoxic agents.

Exogenous nucleosides modulate the expression of rat liver extracellular matrix genes in single cultures of primary hepatocytes and a liver stellate cell line and in their co-culture.

BACKGROUND & AIMS: We have previously reported the antifibrotic effect of dietary nucleotides in cirrhotic rats. In this work, we used primary rat hepatocytes, a liver stellate cell line (CFSC-2G) and co-cultures of both cell types to investigate the effects of exogenous nucleosides on the gene expression of various extracellular matrix components and on markers of liver function, and to ascertain whether the effects found in vivo are due to CFSC-2G, hepatocytes, or are the consequence of cell-cell interactions. RESULTS: Nucleosides enhanced fibronectin, laminin, and alpha1(I) procollagen levels in CFSC-2G and hepatocytes, as well as collagen synthesis and secretion in CFSC-2G. In contrast, nucleosides lowered fibronectin, laminin and alpha1(I) procollagen levels, and decreased collagen synthesis in co-cultures. Matrix metalloproteinase-13 content and collagen secretion increased in co-cultures incubated with nucleosides. Albumin increased in hepatocytes and co-cultures incubated in the presence of nucleosides. CONCLUSIONS: Nucleosides modulate the production of extracellular matrix in single cultures of hepatocytes and of CFSC-2G, and in co-cultures. This effect seems to be regulated at the translational level. The opposite behavior of single cultures and co-cultures is probably due to the fact that the latter model reproduces many of the physical and functional relationships observed in vivo between hepatocytes and stellate cells.

Exogenous nucleosides alter the intracellular nucleotide pool in hepatic cell cultures. Implications in cell proliferation and function.

BACKGROUND & AIMS: Dietary nucleotides are reported to influence the growth and functioning of the liver. The objective of the study was to evaluate the uptake and incorporation of exogenous nucleosides by hepatic cells, and the potential implications for cell proliferation and function. METHODS: Liver stellate cell line CFSC-2G and primary hepatocytes in single and mixed cultures were exposed to mixtures of nucleosides and the concentrations of nucleoside derivatives were determined in the cultures, by high-performance liquid chromatography. Cell proliferation (DNA synthesis, cell cycle) and function (adenylate charge, albumin content, mitochondrial succinate dehydrogenase activity) were also evaluated. RESULTS: The exogenous nucleosides increased the intracellular concentrations of UTP, UDP-glucose, CDP-choline and NAD(+), in the single cultures of CFSC-2G and hepatocytes. Modification of the intracellular nucleotide pool paralleled changes in cell functional status, as indicated by increased adenylate charge and albumin content in hepatocyte cultures and in their co-cultures with CFSC-2G, and by increased succinate dehydrogenase activity in hepatocytes. CONCLUSION: Exogenous nucleosides were taken up by CFSC-2G and hepatocytes, which modified the intracellular concentrations of nucleotides, improved the functional status of hepatocytes, and partially restored the impaired adenylate charge of the co-cultures.

Chronic diarrhea impairs intestinal antioxidant defense system in rats at weaning.

The aim of the present study was to evaluate the influence of severe protein-energy malnutrition on the antioxidant defense system in the small and large intestine in rats at weaning. Chronic diarrhea and the subsequent malnutrition were induced by oral intake of a lactose-enriched diet. Twenty rats were weaned at 21 days of age, and the control group was fed a semipurified synthetic diet for two weeks. The malnourished group was fed the same diet but carbohydrates were replaced by lactose, and they developed diarrhea one day after. Rats were killed, and macroscopic and histological features were analyzed, DNA content was measured, and alkaline phosphatase, myeloperoxidase, and gamma-glutamyltranspeptidase activities were determined to assess the degree of intestinal injury. Glutathione levels as well as the activities of intestinal glutathione transferase, glutathione reductase, total glutathione peroxidase, selenium-dependent glutathione peroxidase, superoxide dismutase, and catalase were measured to study the antioxidant defense system. Malnourished rats showed loss of body weight and an increase in length and weight in jejunum and ileum, while no significant changes were observed in colon. Epithelial cells showed fewer and shorter microvilli, larger mitochondria with low inner density and loss of cristae, dilated endoplasmic reticulum, and Golgi apparatus. The protein-to-DNA ratio was higher in the jejunum, ileum, and colon of malnourished rats. Glutathione levels decreased 40% in jejunum and 50% in colon of malnourished rats. A 40-50% decrease in the activity of all the enzymes of the antioxidant defense system was observed in the jejunum and ileum of malnourished rats, while only catalase and glutathione transferase activities decreased 50% in colon. These results suggest that early chronic diarrhea and severe protein-energy malnutrition impair the antioxidant defense system in both the small and large intestine, which may have a role in the pathogenesis and maintenance of the vicious circle of malabsorption-diarrhea-malnutrition in infancy.

Apoptotic response to TGF-beta in fetal hepatocytes depends upon their state of differentiation.

Transforming growth factor-beta (TGF-beta1) induces death of fetal hepatocytes by an apoptotic mechanism. However, even when very high concentrations and/or long-term exposure to the cytokine is used, 40-50% of cells always survive. The process of cell survival is coincident with changes in morphology and phenotype, with cells showing a fibroblastic appearance and eliciting an epithelial-fibroblastic transition. Surviving cells continue responding to TGF-beta in terms of growth control. Expression of liver-specific genes is very low in these cells; this effect is due to the decrease in their rate of transcription as soon as 2 h after the addition of the factor. Surviving cells present a decreased DNA binding activity for liver-enriched transcription factors, an increased DNA binding activity for AP-1, and a high expression of protooncogenes. These cells are immature hepatocytes since in the presence of the appropriate signal (i.e., epidermal growth factor), they can differentiate, organizing in cell clusters and increasing both liver-specific mRNA expression and liver-enriched transcription factor activity. In accord with these results, TGF-beta, secreted at high concentrations during liver carcinogenesis, might induce death of normal cells while providing a selective advantage for the survival of cells that are "partially transformed" or "less differentiated" and unresponsive to the factor.

Dietary phospholipids rich in long-chain polyunsaturated fatty acids improve the repair of small intestine in previously malnourished piglets.

Malnourished piglets were studied to establish how a diet containing long-chain polyunsaturated fatty acids (LC-PUFA) of the (n-6) and (n-3) series, esterified in the form of phospholipids, affects intestinal recovery after severe malnutrition. Piglets (7-d-old) were randomly assigned to two groups. One group was fed a piglet milk formula and the other was malnourished by protein-energy restriction for 30 d. Healthy and malnourished piglets were then divided into two subgroups fed for 10 d either an adapted milk formula (C and M) or the same diet supplemented with LC-PUFA phospholipids (C-P and M-P). The M-P group had greater protein, DNA, cholesterol and phospholipid levels and a lower triglyceride level in the jejunal segment than did the M group. The fatty acid composition of the jejunal mucosa and microsomes of the M-P piglets did not differ from that of healthy piglets (C). However, in jejunal mucosa, microsomes and phospholipids from malnourished piglets that did not receive LC-PUFA (group M) had significantly lower percentages of (n-6) LC-PUFA than those in healthy piglets (C). The (n-3) LC-PUFA percentages of jejunal mucosa were also lower in the M group than in the C group. The small intestine of piglets fed the LC-PUFA-supplemented formula recovered more completely from histologic lesions and biochemical alterations caused by the malnutrition process than the small intestine of piglets fed the control formula without LC-PUFA.

Olive oil- and fish oil-enriched diets modify plasma lipids and susceptibility of LDL to oxidative modification in free-living male patients with peripheral vascular disease: the Spanish Nutrition Study.

The present study describes a clinical trial in which Spanish patients suffering from peripheral vascular disease (Fontaine stage II) were given specific lipid supplements. Designed as a longitudinal intervention study, patients were provided with olive oil for 3 months, followed by a 3 month wash-out period, then supplemented with a combination of fish oil and olive oil for the final 3 months. Changes in plasma and lipoprotein fatty acid composition and susceptibility of LDL to in vitro oxidation were examined. Furthermore, lipid-supplement-induced changes in LDL properties were measured as relative electrophoretic mobility and macrophage uptake. In addition, thirteen patients not provided with olive oil and fish oil were included as a control group and twenty healthy age-matched individuals were used as a reference group. A complete clinical study and a nutritional survey concerning food habits and lifestyle were performed every 3 months. Yao indices and claudicometry did not change significantly with dietary intervention although changes in plasma lipid composition suggested an improvement in the condition of the patients. The intake of the fish-oil supplement resulted in significantly increased plasma levels of eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3) in comparison with baseline concentrations, olive-oil and control groups. Fish-oil consumption significantly decreased plasma triacylglycerol levels compared with the olive-oil period, control and reference groups. The susceptibility of LDL to Cu-mediated oxidation was lower in the patients consuming olive oil and the fish-oil supplement than in the control group, and the uptake of LDL by macrophages was significantly lower in the group supplemented with fish oil. In conclusion, consumption of olive oil together with a dietary supplement of fish oil may be useful in the nutritional management of patients suffering from peripheral vascular disease in terms of increasing plasma n-3 long-chain polyunsaturated fatty acids and decreasing susceptibility of LDL to oxidation.

Severe malnutrition alters lipid composition and fatty acid profile of small intestine in newborn piglets.

The goal of this study was to evaluate the influence of severe protein-energy malnutrition (PEM) on lipid composition and fatty acid profile in the small intestinal mucosa of lactating pigs. Malnutrition was achieved by 80% protein-energy restriction for 30 d (20% of the food intake in the control group) in 7-d-old newborn piglets. Malnourished piglets had significantly lower concentrations of cholesterol, phospholipid and triglycerides in the jejunum and ileum compared with freely fed controls. Fatty acid composition of the intestinal mucosa was severely affected by malnutrition. A sharp decline in the relative percentages of (n-3) and (n-6) long-chain polyunsaturated fatty acids (LC-PUFA) in malnourished piglets paralleled higher (n-9) fatty acid proportions in the total mucosa, microsomes and phospholipids of the jejunum. The structure of the small intestine was severely affected as assessed by light and electron microscopy, and alkaline phosphatase and disaccharidase activities in the intestinal mucosa were also significantly impaired. Plasma from malnourished piglets had significantly lower concentrations of (n-3) and (n-6) LC-PUFA than that of control piglets; however, the fatty acid composition of red blood cell membrane was unaffected. Our results suggest that early severe PEM dramatically modifies intestinal membrane lipid composition. Changes in the lipid composition of the small intestinal mucosa and in phospholipid distribution as well as in the fatty acid profile may alter membrane fluidity and organization. These alterations appear to affect the activity of membrane-bound hydrolytic enzymes.