Immune-enhancing enteral diet increases blood flow and proinflammatory cytokines in the rat ileum

Enteral ecoimmunonutrition reduced enteral permeability and serum ghrelin activity in severe cerebral stroke patients with lung infection

The study analyzed how enteral ecoimmunonutrition, which comprises probiotics, glutamine, fish oil, and Enteral Nutritional Suspension (TPF), can impact on the enteral permeability and serum Ghrelin activity in severe cerebral stroke patients with lung infection. Among 190 severe cerebral stroke patients with tolerance to TPF, they were randomized into control and treatment groups after antibiotics treatment due to lung infections. There were 92 patients in the control group and 98 patients in treatment group. The control group was treated with TPF and the treatment group was treated with enteral ecoimmunonutrition, which comprises probiotics, glutamine, fish oil, and Enteral Nutritional Suspension. All patients received continuous treatments through nasoenteral or nasogastric tubes. 7, 14, and 21 days after the treatments, the enteral tolerance to nutrition was observed in both groups. The tests included abdominal pain, bloating, diarrhea, and lactulose/mannitol (L/M) ratio. Serum Ghrelin levels were determined by ELISA. The incidence of abdominal pain, bloating, diarrhea was lower in the treatment group and enteral tolerance to nutrition was also superior to the control group. No difference in serum Ghrelin level was observed between the control and treatment groups with enteral intolerance to nutrition. However, in patients with enteral tolerance to nutrition, the treatment group showed lower enteral nutrition and lower enteral permeability compared to the control group. In severe cerebral stroke patients with lung infection, enteral ecoimmunonutrition after antibiotics treatment improved enteral tolerance to nutrition and reduced enteral permeability; meanwhile, it lowered the serum Ghrelin activity, which implied the high serum Ghrelin reduces enteral permeability.

Fish oil increases blood flow in the ileum during chronic feeding in rats

Benefits of enteral feeding with immune-enhancing diets (IEDs) depend on route, timing, and composition. We hypothesized that chronic enteral feeding with certain individual immunonutrients would enhance gastrointestinal blood flow. Male rats were fed a standard enteral diet supplemented with immunonutrients for 5 days before study. Groups were (1) standard rat chow, (2) liquid control diet (CD) alone (CD), (3) CD + fish oil, (4) CD + L-arginine, and (5) CD + RNA fragments. Whole organ blood flow distribution was measured by colorimetric microsphere technique in antrum, small intestine (in thirds), colon, liver, spleen, pancreas, and kidneys. Chronic feeding for 5 days with CD + fish oil increased blood flow in the distal third of the small intestine compared with CD alone, whereas feeding with CD + L-arginine decreased blood flow in the small intestine (all segments) compared with CD alone. Acute gavage of CD + L-arginine or CD + fish oil increased blood flow in the proximal and middle third of the small intestine compared with CD alone. Control diet + RNA increased blood flow in the proximal small intestine compared with CD alone. These findings support prior acute feeding studies with CD, CD + individual immunonutrients, or IED. Our current data suggest that blood flow benefits associated with fish oil persist during chronic feeding in rats. Enhanced gastrointestinal perfusion might partially explain the benefits of early enteral feeding with IEDs not seen with regular enteral diets and parenteral immunonutrient delivery.

The role of nucleotides in the immune and gastrointestinal systems: potential clinical applications

Nucleotides are low molecular weight biological molecules key to biochemical processes. Sources include de novo synthesis, recovery via salvage mechanisms, and dietary intakes. Although endogenous production serves as the main nucleotide source, evidence suggests that exogenous sources are essential to immune competence, intestinal development, and recovery. Dietary nucleotides serve a marked role in rapidly proliferating cells where they are necessary for optimal function. Accordingly, dietary nucleotides are deemed conditionally essential in the presence of various physiological stresses, including growth and development, recovery from injury, infection, and certain disease states. Clinical studies that evaluated nutrition formulations of nucleotides in combination with other specific nutrient substances demonstrated improved clinical outcomes in patients characterized as critically ill, injured, immune suppressed, or with chronic gastrointestinal conditions. However, conclusions regarding specific benefits of nucleotides are limited. Scientific substantiation of nucleotide supplementation in infant formula has been reported to improve the maturation and development of the intestinal tract as well as immune function. All medical nutrition products except for one immune-modulating formulation are devoid of nucleotides. In an effort to build on this, the current review presents the data to support potential clinical applications for nucleotides in enteral nutrition that may contribute to improved outcomes in physiologically stressed patients.

Obesity, inflammation, and the potential application of pharmaconutrition

Obesity is an emerging problem worldwide. Hospitalized obese patients often have a worse outcome than patients of normal weight, particularly in the setting of trauma and critical care. Obesity creates a low-grade systemic inflammatory response syndrome (SIRS) that is similar (but on a much smaller scale) to gram-negative sepsis. This process involves up-regulation of systemic immunity, is characterized clinically by insulin resistance and the metabolic syndrome, and puts the patient at increased risk for organ failure, infectious morbidity, and mortality. Through lipotoxicity and cytokine dysregulation, obesity may act to prime the immune system, predisposing to an exaggerated subsequent immune response when a second clinical insult occurs (such as trauma, burns, or myocardial infarction). Specialized nutrition therapy for such patients currently consists of a hypocaloric, high-protein diet. However, this approach does not address the putative pathophysiologic mechanisms of inflammation and altered metabolism associated with obesity. A number of dietary agents such as arginine, fish oil, and carnitine may correct these problems at the molecular level. Pharmaconutrition formulas may provide exciting innovations for the nutrition therapy of the obese patient.

Enteric neural pathways mediate the anti-inflammatory actions of glucagon-like peptide 2

Glucagon-like peptide-2 (GLP-2) is an important regulator of nutritional absorptive capacity with anti-inflammatory actions. We hypothesized that GLP-2 reduces intestinal mucosal inflammation by activation of vasoactive intestinal polypeptide (VIP) neurons of the submucosal plexus. Ileitis or colitis was induced in rats by injection of trinitrobenzene sulfonic acid (TNBS), or colitis was induced by administration of dextran sodium sulfate (DSS) in drinking water. Subsets of animals received (1-33)-GLP-2 (50 mug/kg sc bid) either immediately or 2 days after the establishment of inflammation and were followed for 3-5 days. The involvement of VIP neurons was assessed by concomitant administration of GLP-2 and the VIP antagonist [Lys(1)-Pro(2,5)-Arg(3,4)-Tyr(6)]VIP and by immunohistochemical labeling of GLP-2-activated neurons. In all models, GLP-2 treatment, whether given immediately or delayed until inflammation was established, resulted in significant improvements in animal weights, mucosal inflammation indices (myeloperoxidase levels, histological mucosal scores), and reduced levels of inflammatory cytokines (IFN-gamma, TNF-alpha, IL-1beta) and inducible nitric oxide synthase, with increased levels of IL-10 in TNBS ileitis and DSS colitis. Reduced rates of crypt cell proliferation and of apoptosis within crypts in inflamed tissues were also noted with GLP-2 treatment. These effects were abolished with coadministration of GLP-2 and the VIP antagonist. GLP-2 was shown to activate neurons and to increase the number of cells expressing VIP in the submucosal plexus of the ileum. These findings suggest that GLP-2 acts as an anti-inflammatory agent through activation of enteric VIP neurons, independent of proliferative effects. They support further studies to examine the role of neural signaling in the regulation of intestinal inflammation.

Use of serum leptin levels for determination of nutritional status and the effects of different enteral nutrients on intestinal mucosa after minor surgery: an experimental study

BACKGROUND

We planned to evaluate the effects of different enteral nutrients on the levels of serum leptin, protein and albumin changes and also to compare their effects on mucosal morphology of small intestine.

METHODS

Rats were randomly divided into 5 groups each including 10 animals. Group I rats were given rat chow and water. Group II rats were fed with standard enteral nutrient. Group III rats were fed with calorie enriched enteral nutrient. Group IV rats were given enteral nutrition supplemented with fiber. Group V rats were fed with immunonutrient. Serum albumin, protein, leptin levels were measured. Terminal ileum of each rat was scored.

RESULTS

We found no difference in serum leptin, protein and albumin levels. The average mucosal atrophy of rats fed with standard chow was significantly different than that of rats fed with standard and calorie enriched nutrients. Feeding with nutrients supplemented with fiber and immunonutrient did not cause significant distortion in mucosal integrity when compared with feeding with standard chow.

CONCLUSION

Low levels of leptin may show malnutrition but for determination of nutritional status of a patient receiving enteral nutrition, studies with long duration are required.

Fish oil in the critically ill: from experimental to clinical data

PURPOSE OF REVIEW

The aim of this paper is to describe recent relevant literature concerning the role of n-3 lipids derived from fish oil in clinical nutrition in an intensive care setting.

RECENT FINDINGS

N-3 fatty acids compete with arachidonic acid for metabolism to lipid mediators and exert profound effects on second mediator generation and dependent cellular functions. In experimental models, dietary and parenteral use of fish oil was shown to protect the gut by increasing its perfusion. In contrast, use of immunonutrition including fish oil in critical ill patients or patients with severe sepsis may exert an excess mortality. Using parenteral fish oil in surgical patients promising data became available. In septic patients, immunologic effects of fish oil-based lipid emulsions have been found and intravenous supplementation with fish oil may have a beneficial impact on mortality and length of stay. For both patient groups, however, prospective data from randomized trials are lacking.

SUMMARY

N-3 lipids exhibit strong immunologic properties. They offer the possibility to counterbalance the negative effects of conventional n-6 fatty acids. Recent studies exhibit positive effects of intravenous use of fish oil on immunologic functions and clinical parameters in surgical and septic patients.

The role of macronutrients in gastrointestinal blood flow

PURPOSE OF REVIEW

The presence of luminal nutrients after a meal increases gastrointestinal blood flow in a phenomenon called postprandial hyperemia. In many conditions related to splanchnic hypoperfusion, enteral nutrition may play a role in counterbalancing the installed splanchnic low-flow state by producing intestinal hyperemia. However, when the gut is hypoperfused there is a chance of enteral nutrition producing a mismatch of the oxygen demand: supply ratio with subsequence gut ischemia. This article aims to review the effects of macronutrients on gastrointestinal blood flow in both health and critical conditions, especially those related to hepatosplanchnic hypoperfusion.

RECENT FINDINGS

Splanchnic blood flow is related not only to the route (intravenous or enteral) and timing of nutritional support (during the course of the insult) but also to the composition of the formula. Critically ill patients with gut hypoperfusion may tolerate enteral nutrition, but this effect may be restricted to the early post-injury phase. During ischaemia reperfusion injury, immune nutrients may promote different outcomes: glutamine may protect whereas arginine may deteriorate the mucosal barrier and enhance permeability.

SUMMARY

Understanding the relationship between macronutrients and gastrointestinal blood flow is a major challenge. Ongoing research in nutritional support in hypoperfused, catecholamine-dependent patients will open the door to optimize the recovery of patients in critical care.

Dietary nucleotides and intestinal blood flow velocity in term infants

OBJECTIVES

Two previous studies have shown that the addition of nucleotides to single feedings of formula is associated with increased 90-minute postprandial superior mesenteric artery (SMA) blood flow velocity (BFV). To assess the effect of chronic feeding of nucleotide-supplemented formula, we measured pre- and postprandial SMA BFV in term infants fed formula with or without added nucleotides for 4 weeks.

METHODS

At 1 week of age, healthy, term infants were randomized to receive formula with added nucleotides (NT+), or formula without added nucleotides (NT-) from age 1 to 5 weeks. When the infants were 5 weeks of age, SMA BFV was measured by Doppler ultrasound 15 minutes before the assigned feeding (baseline) and 30, 60, and 90 minutes after the start of feeding. A reference group of human milk-fed infants was studied before and after breast feeding.

RESULTS

Thirty formula-fed (NT+ = 17; NT- = 13) and 10 human milk-fed infants were studied. Baseline BFV was similar among the three groups. BFV increased in each group from baseline to 30 minutes after initiation of feeding and progressively declined from 30 to 90 minutes in infants fed NT- formula or human milk. In infants fed NT+ formula, BFV decreased between 30 and 60 minutes. However, from 60 to 90 minutes, velocity was unchanged or increased. At 90 minutes, mean and peak systolic velocities were significantly greater in the NT+ group than the NT- group (P < 0.001).

CONCLUSIONS

These data agree with those of previous studies showing increased 90-minute postprandial SMA BFV after a feeding with nucleotide-supplemented formula. The clinical significance of these findings is unknown.

Effects of different operations on cirrhotic portal hypertensive liver in rats

AIM: To evaluate respectively the effects of portaazygous disconnection (PAD), mesocaval shunt (MCS) and distal splenocaval shunt (DSCS) on the portasytemic shunting (PSS), hepatic function (HF), hepatic mitochondrial respiratory function (HMRF) and its ultrastructure, anti-oxidation ability (HAOA) and lipoperoxide (LPO), so as to provide theoretical basis to select a suitable operation.

METHODS: Using the cirrhotic portal hypertensive model induced by CCl₄/ethanol in Wristar rats, we investigated PSS, HF, HMRF and its HAOA and LPO during three wks after MCS, DSCS and PAD.

RESULTS: After MCS, the PSS were further increased, HF, HMRF and HAOA were significantly decreased, and LPO increased. Hepatic mitochondrial ultrastructure showed severely damaged. Only a little improvement was found on the third wk. After DSCS and PAD, above mentioned indexes were less influenced, and they were restored a little more quickly in DSCS groups than that in PAD groups. During the first postoperative wk, the PAD group showed the highest mortality.

CONCLUSION: DSCS may be a desirable operation among the three kinds of operation.