The role of macronutrients in gastrointestinal blood flow

New insights into the role of dietary triglyceride absorption in obesity and metabolic diseases

The incidence of obesity and associated metabolic diseases is increasing globally, adversely affecting human health. Dietary fats, especially triglycerides, are an important source of energy for the body, and the intestine absorbs lipids through a series of orderly and complex steps. A long-term high-fat diet leads to intestinal dysfunction, inducing obesity and metabolic disorders. Therefore, regulating dietary triglycerides absorption is a promising therapeutic strategy. In this review, we will discuss diverse aspects of the dietary triglycerides hydrolysis, fatty acid uptake, triglycerides resynthesis, chylomicron assembly, trafficking, and secretion processes in intestinal epithelial cells, as well as potential targets in this process that may influence dietary fat-induced obesity and metabolic diseases. We also mention the possible shortcomings and deficiencies in modulating dietary lipid absorption targets to provide a better understanding of their administrability as drugs in obesity and related metabolic disorders.

Roasted Barley Extract Affects Blood Flow in the Rat Tail and Increases Cutaneous Blood Flow and Skin Temperature in Humans

Roasted barley extract (RBE, "Mugicha") is a traditional Japanese beverage reported to improve blood viscosity and affect food functionality. RBE is suggested to contain 2,5-diketopiperazines, which are the functional component with neuroprotective and immunostimulatory effects that are produced in food through roasting. In this study, we investigated the effects of RBE on blood circulation, both clinically and in rats. At first, we confirmed five 2,5-diketopiperazine derivatives in RBE by LC-MS analysis. Secondarily, we revealed that RBE affects blood flow in the rat tail and compared the efficacy on rat tail blood flow among five 2,5-diketopiperazines in RBE. Especially, cyclo(d-Phe-l-Pro) was the most effective in increasing blood flow in the rat tail. We also researched the mechanism of cyclo(d-Phe-l-Pro) with rat aorta study. As a result, we confirmed that cyclo(d-Phe-l-Pro) has an effect on vasodilatation through the release of nitric oxide in the vascular endothelium. Finally, we also confirmed that RBE affects cutaneous blood flow and increases skin temperature in humans.

2-Ethylpyrazine Induces Vasodilatation by Releasing Nitric Oxide in the Endothelium

Oxygen transportation and regulation of some physiological processes are facilitated by blood flow. Furthermore, blood flow is regulated by various factors such as nitric oxide (NO) and the autonomic nerve system. In modern life, many people suffer from chilliness (hiesho) because of mental stress and an excessive use air-conditioning systems, which induces vasoconstriction in the peripheral skin. In this study, we focused on pyrazine derivatives, particularly compounds that are used as food flavoring materials, and investigated their effects on vascular function and blood flow. We examined the vasodilatory effect of pyrazine derivatives in the rat thoracic aorta and found 2-ethylpyrazine (2-EP) to be the most active pyrazine compound. Additionally, we found that 2-EP induces vasodilatation through the activities of endothelium-derived relaxing factors. 2-EP activates NO synthesis through the effect of endothelial NO synthase in the endothelium. As a result, cyclic GMP levels rise in smooth muscle cells and vasodilatation is induced. We also confirmed that 2-EP increases peripheral blood flow in rats. From these results, we concluded that 2-EP induces vasodilatation by inducing the release of NO and increasing peripheral blood flow.

Lymphatic diamine oxidase secretion stimulated by fat absorption is linked with histamine release

Diamine oxidase (DAO) is abundantly expressed in mammalian small intestine catalyzing the oxidative breakdown of polyamines and histamine. The aim of this study was to determine the relationship between stimulation of intestinal diamine oxidase secretion with intestinal fat absorption and histamine release. Conscious intestinal lymph fistula rats were used. The mesenteric lymph ducts were cannulated and intraduodenal tubes were installed for the infusion of Liposyn II 20% (an intralipid emulsion). Lymphatic DAO activity and protein secretion were analyzed by radiometric assay and Western blot, respectively. Lymphatic histamine concentration was measured by ELISA. Infusion of Liposyn II (4.43 kcal/3 ml) resulted in a ~3.5-fold increase in lymphatic DAO protein secretion and DAO activity, peaking at 1 h and lasting for 3 h. Liposyn II infusion also increased the lymphatic histamine release, a substrate for DAO. To determine the relationship of DAO release with histamine release, histamine was administered intraperitoneally (10 mg/kg) in fasting rats and resulted in a significant doubling in lymphatic DAO activity, supporting a link between histamine and DAO. In addition, ip administration of the histamine H4 receptor antagonist JNJ7777120 significantly reduced the Liposyn II-induced DAO output by 65.9%, whereas H(1) (pyrilamine maleate), H(2) (ranitidine), and H(3) (thioperamide maleate) receptor antagonists had little effect. We conclude that DAO secretion may contribute to the catabolism of histamine released during fat absorption and this is probably mediated through the histamine H(4) receptor.

Disease-specific nutrition therapy: one size does not fit all

INTRODUCTION

The delivery of adequate nutrition is an integral part of the care of the critically ill surgical patient, and the provision of nutrition may have a greater impact on outcome than many other therapies commonly employed in the treatment of certain disease states.

METHODS

A review of the existing literature was performed to summarize the evidence for utilizing disease-specific nutrition in critically ill surgical patients.

RESULTS

Enteral nutrition, unless specifically contraindicated, is always preferable to parenteral nutrition. Methodological heterogeneity and conflicting results plague research in immunonutrition, and routine use is not currently recommended in critically ill patients.

CONCLUSION

There is currently insufficient evidence to recommend the routine initial use of most disease-specific formulas, as most patients with the disease in question will tolerate standard enteral formulas. However, the clinician should closely monitor for signs of intolerance and utilize disease-specific formulas when appropriate.

Association between illness severity and timing of initial enteral feeding in critically ill patients: a retrospective observational study

Background

Early enteral nutrition is recommended in cases of critical illness. It is unclear whether this recommendation is of most benefit to extremely ill patients. We aim to determine the association between illness severity and commencement of enteral feeding.

Methods

One hundred and eight critically ill patients were grouped as “less severe” and “more severe” for this cross-sectional, retrospective observational study. The cut off value was based on Acute Physiology and Chronic Health Evaluation II score 20. Patients who received enteral feeding within 48 h of medical intensive care unit (ICU) admission were considered early feeding cases otherwise they were assessed as late feeding cases. Feeding complications (gastric retention/vomiting/diarrhea/gastrointestinal bleeding), length of ICU stay, length of hospital stay, ventilator-associated pneumonia, hospital mortality, nutritional intake, serum albumin, serum prealbumin, nitrogen balance (NB), and 24-h urinary urea nitrogen data were collected over 21 days.

Results

There were no differences in measured outcomes between early and late feedings for less severely ill patients. Among more severely ill patients, however, the early feeding group showed improved serum albumin (p = 0.036) and prealbumin (p = 0.014) but worsened NB (p = 0.01), more feeding complications (p = 0.005), and prolonged ICU stays (p = 0.005) compared to their late feeding counterparts.

Conclusions

There is a significant association between severity of illness and timing of enteral feeding initiation. In more severe illness, early feeding was associated with improved nutritional outcomes, while late feeding was associated with reduced feeding complications and length of ICU stay. However, the feeding complications of more severely ill early feeders can be handled without significantly affecting nutritional intake and there is no eventual difference in length of hospital stay or mortality between groups. Consequently, early feeding shows to be a more beneficial nutritional intervention option than late feeding in patients with more severe illness.

Nutrient-induced inflammation in the intestine

PURPOSE OF REVIEW

To review our current understanding of the relationship between absorption of nutrients and intestinal inflammatory response.

RECENT FINDINGS

There is increasing evidence linking gut local inflammatory events with the intake of nutrients. Our recent studies, using the conscious lymph fistula rat model, demonstrate that fat absorption activates the intestinal mucosal mast cells. This is accompanied by a dramatic increase in the lymphatic release of mast cell mediators including histamine, rat mucosal mast cell protease II (RMCPII), as well as the lipid mediator prostaglandin D2 (PGD2). Clinical studies suggest that increased consumption of animal fat may play a role in the pathogenesis of inflammatory bowel disease. This impact of dietary fat may not be restricted to the gut but may extend to the whole body. There is evidence linking a high-fat diet-induced metabolic syndrome, with a low-grade chronic inflammatory state. In this review, we hope to convince the readers that fat absorption can have far reaching physiological and pathophysiological consequences.

SUMMARY

Understanding the relationship between nutrient absorption and intestinal inflammation is important. We need a better understanding of the interaction between enterocytes and the intestinal immune cells in nutrient absorption and the gut inflammatory responses.

Focal ischemic necrosis in advanced biliary atresia cirrhosis

This report correlates the clinical and biological findings, liver hemodynamics and histological features of focal INL in an infant with BA cirrhosis. An eight month old boy with BA, with previous successful porto-enterostomy, was admitted with signs of cholangitis and ascites. He was treated with antibiotics and diuretics with subsequent clinical improvement. Eight days later, while being fed with hyper-osmolar milk, he became febrile again: ASAT/ALAT climbed (9000/2300 IU/L), liver function deteriorated. Infectious work-up was negative. Liver-ultrasound showed reversed portal flow and a negative arterial diastolic flow. The patient recovered within five days under supportive treatment. A similar event recurred five days later. INL was suspected and semi-urgent living-related liver transplantation was performed, with uneventful post-operative course. Histology of the explanted liver showed extensive foci of INL of different ages. This report illustrates how the association of reversed portal and arterial diastolic flows, with subsequent liver hypoperfusion, may repeatedly cause foci of INL in BA cirrhosis, and lead to rapid progression to liver failure. Because of precarious hepatic blood supply in such patients, close monitoring of portal and diastolic arterial flows is recommended.

Comparison of hormonal and metabolic markers after a high-fat, Western meal versus a low-fat, high-fiber meal in women with polycystic ovary syndrome

OBJECTIVE

To determine the effect of meal composition on postprandial T levels in women with polycystic ovary syndrome (PCOS).

DESIGN

Randomized, crossover design.

SETTING

Academic research center.

PATIENT(S)

Fifteen women with PCOS.

INTERVENTION(S)

We evaluated changes in T, sex hormone binding globulin (SHBG), DHEAS, cortisol, glucose, and insulin for 6 hours after a high-fat, Western meal (HIFAT) (62% fat, 24% carbohydrate, 1 g fiber) and an isocaloric low-fat, high-fiber meal (HIFIB) (6% fat, 81% carbohydrate, 27 g fiber).

MAIN OUTCOME MEASURE(S)

Change in T levels.

RESULT(S)

Testosterone decreased 27% within 2 hours after both meals. However, T remained below premeal values for 4 hours after the HIFIB meal and 6 hours after the HIFAT meal. Insulin was twofold higher for 2 hours after the HIFIB meal compared with the HIFAT meal. Glucose was higher for 1 hour after the HIFIB meal compared with the HIFAT meal. DHEAS decreased 8%-10% within 2-3 hours after both meals, then increased during the remainder of the study period. Cortisol decreased during the 6-hour period after both meals.

CONCLUSIONS

Diet plays a role in the regulation of T levels in women with PCOS. Further studies are needed to determine the role of diet composition in the treatment of PCOS.

Early nutrition support in the intensive care unit: a US perspective

PURPOSE OF REVIEW

Early nutrition support, defined as within the first 24-48 h of ICU care, is recommended by clinical practice guidelines. The purpose of this paper is to provide an evidence-based US perspective on early nutrition support in critical illness, explain its mechanism of action, and describe its implementation using combined enteral and parenteral nutrition support.

RECENT FINDINGS

Recent American and Canadian guidelines recommend starting enteral nutrition within the first 24-48 h of ICU care. This is mainly due to accrued 'energy debt' from underfeeding in certain patients. This energy debt leads to increased risks of complications and longer lengths of stay. Strong clinical evidence, however, in the form of prospective, randomized, controlled intervention studies of early nutrition support in the setting of routine intensive insulin therapy, is lacking.

SUMMARY

Early enteral nutrition should be first-line therapy in the ICU. If a caloric goal of 20-25 kcal/kg/day is not possible, then combined enteral and parenteral nutrition should be started. In the new age of intensive insulin therapy, parenteral nutrition has not been shown to confer significant additional infective risk. There are many unanswered questions, but a proactive posture for metabolic support in the ICU is advocated.

Associação de glutamina e probióticos no trofismo mucoso do cólon na peritonite experimental

OBJETIVO: O objetivo deste estudo foi investigar o efeito da associação da glutamina e probióticos sobre a mucosa intestinal em ratos submetidos à peritonite experimental. MÉTODO: 16 ratos Wistar (250-350g) com peritonite experimental criada pelo método da punção dupla do ceco foram randomizados para receber diariamente no pós-operatório em conjunto com a dieta, a adição por gavagem de 0,500g de glutamina e leite reconstituído, contendo probióticos (10(6) unidades formadoras de colônias/g de Bifidobacterium lactis BL e Streptococcus thermophilus) (grupo glutamina-probióticos; n=8) ou 0,495g de caseína e leite reconstituído sem probióticos (grupo controle; n=8). O conteúdo das duas dietas foi isonitrogenado e isocalórico. Todos os animais foram sacrificados 120 horas após a peritonite experimental. A profundidade de criptas e espessura de parede da mucosa do cólon foram medidas em biopsias realizadas 2 cm acima da reflexão peritoneal. O restante da mucosa colônica foi pesado e nela mensurou-se o conteúdo de DNA. RESULTADOS: Os animais que receberam glutamina e probióticos apresentaram mucosa mais pesada (0,49±0,12 vs. 0,42±0,07g; p=0,02), maior conteúdo de DNA (0,31±0,07 vs. 0,22±0,05 mg/g de tecido; p<0,01) e criptas mais profundas (272±51 vs. 311±39µ; p=0,04) que o grupo controle. CONCLUSÃO: A associação da glutamina e probióticos confere um maior trofismo na mucosa colônica em ratos submetidos à peritonite experimental.

An evaluation of the effect of a gastric ischemia-reperfusion model with laser Doppler blood perfusion imaging

The objectives of this study are to establish a gastric ischemia-reperfusion model and test it using the laser Doppler blood perfusion imaging (LDPI) method and to evaluate the role of the LDPI technique in the measure of gastric blood circulation. The right gastric artery of the rat was clamped for 30 min and then reperfused. The LDPI was used to display the blood circulation of the whole gastric surface during this process. The blood flow perfusion image of the gastric surface was displayed clearly. After the right gastric artery was clamped, the blood flow perfusion on the gastric surface decreased very significantly until the clamp was loosened. Following reperfusion, the blood flow suddenly increased. Within the first 10 min, the blood-flow perfusion exceeded the level before the clamping and then gradually became smooth and steady. The right gastric artery is a main pathway for gastric blood supply. LDPI can display successfully the blood circulation state of the stomach and the course of ischemia-reperfusion of a large area with an image.