Arginine-enriched total parenteral nutrition improves survival in peritonitis by normalizing NFkappaB activation in peritoneal resident and exudative leukocytes

An Immune-Regulating Polysaccharide Hybrid Hydrogel with Mild Photothermal Effect and Anti-Inflammatory for Accelerating Infected Wound Healing

Bacterial infections and excessive inflammation present substantial challenges for clinical wound healing. Hydrogels with mild photothermal (PTT) effects have emerged as promising agents owing to their dual actions: positive effects on cells and negative effects on bacteria. Here, an injectable self-healing hydrogel of oxidized konjac glucomannan/arginine-modified chitosan (OKGM/CS-Arg, OC) integrated with protocatechualdehyde-@Fe (PF) nanoparticles capable of effectively absorbing near-infrared radiation is synthesized successfully. The OC/PF hydrogels exhibit excellent mechanical properties, biocompatibility, and antioxidant activity. Moreover, in synergy with PTT, OC/PF demonstrates potent antibacterial effects while concurrently stimulating cell migration and new blood vessel formation. In methicillin-resistant Staphylococcus aureus-infected full-thickness mouse wounds, the OC/PF hydrogel displays remarkable antibacterial and anti-inflammatory activities, and accelerates wound healing by regulating the wound immune microenvironment and promoting M2 macrophage polarization. Consequently, the OC/PF hydrogel represents a novel therapeutic approach for treating multidrug-resistant bacterial infections and offers a technologically advanced solution for managing infectious wounds in clinical settings.

Role of nutrition in gastroenterological surgery

Nutrition plays important roles in recovery after gastroenterological surgery. Severe surgical stress increases muscle breakdown and lipolysis, thereby accelerating wound healing and enhancing host defense against microbes. Malnourished patients have insufficient amounts of muscle and body fat. Therefore, they may not appropriately respond to surgical stress. Perioperative nutritional therapy maintaining nutritional status reduces postoperative complications and accelerates recovery after surgery, particularly for malnourished patients. In addition, perioperative oral or enteral nutrition is now recommended for preserving host defense mechanisms against microbes. Lack of enteral nutrition impairs gut and hepatic immunity, systemic mucosal defense and peritoneal host defense, even when nutrient amounts supplied by parenteral nutrition are adequate. Thus, surgeons should avoid no oral or enteral nutrition periods. Supplemental administration of specific nutrients such as glutamine, arginine and ω-3 fatty acids is termed "immunonutrition", and is expected to reduce the morbidity of infectious complications and length of hospital stay. Nutritional therapy is important even after discharge to maintain body weight and compensate for abnormalities in the digestion and absorption of nutrients. Understanding the significance of nutrition in gastroenterological patients leads to better outcomes.

Enteral immunonutrition versus enteral nutrition for gastric cancer patients undergoing a total gastrectomy: a systematic review and meta-analysis

Background

Nutrition support is a common means for patients with gastric cancer, especially for those undergoing elective surgery. Recently, enteral immunonutrition (EIN) was increasingly found to be more effective than enteral nutrition (EN) in enhancing the host immunity and eventually improving the prognosis of gastric cancer patients undergoing gastrectomy. However, the results reported were not consistent. This meta-analysis aimed to assess the impact of EIN for patients with GC on biochemical, immune indices and clinical outcomes.

Methods

Four electronical databases (Medline, EMBASE, Scopus and Cochrane library) were used to search articles in peer-reviewed, English-language journals. Mean difference (MD), Relative risk (RR), or standard mean difference (SMD) with 95% confidence interval (CI) were calculated. Heterogeneity was assessed by Cochrane Q and I² statistic combined with corresponding P-value. The analysis was carried out with RevMan 5.3.

Results

Seven studies involving 583 patients were eligible for the pooled analysis. EIN, when beyond a 7-day time-frame post-operatively (D ≥ 7), increased level of CD4⁺ (SMD = 0.99; 95% CI, 0.65–1.33; P < 0.00001), CD4⁺/ CD8⁺ (SMD = 0.34; 95% CI, 0.02–0.67; P = 0.04), the IgM (SMD = 1.15; 95% CI, 0.11–2.20; P = 0.03), the IgG (SMD = 0.98; 95% CI, 0.55–1.42; P < 0.0001), the lymphocyte (SMD = 0.69; 95% CI, 0.32–1.06; P = 0.0003), and the proalbumin (SMD = 0.73; 95% CI, 0.33–1.14; P = 0.0004). However, those increased effects were not obvious within a 7-day time-frame post-operatively (D < 7). The levels of CD8⁺ and other serum proteins except proalbumin were not improved both on D ≥ 7 and D < 7. Clinical outcomes such as systemic inflammatory response syndrone (SIRS) (MD, - 0.89 days; 95% CI, - 1.40 to - 0.39; P = 0.005), and postoperative complications (RR, 0.29; 95% CI, 0.14–0.60; P = 0.001) were significantly reduced in EIN group. Pulmonary infection and length of hospitalization (LHS) were not improved no matter what time after surgery.

Conclusions

EIN was found to improve the cellular immunity, modulate inflammatory reaction and reduce postoperative complication for GC patients undergoing radical gastrointestinal surgery. Exclusion of grey literature and non-English language studies was the key limitation in this study.

Enteral nutrient deprivation in patients leads to a loss of intestinal epithelial barrier function

OBJECTIVE

To investigate the effect of nutrient withdrawal on human intestinal epithelial barrier function (EBF). We hypothesized that unfed mucosa results in decreased EBF. This was tested in a series of surgical small intestinal resection specimens.

DESIGN

Small bowel specifically excluding inflamed tissue, was obtained from pediatric patients (aged 2 days to 19 years) undergoing intestinal resection. EBF was assessed in Ussing chambers for transepithelial resistance (TER) and passage of fluorescein isothiocyanate (FITC)-dextran (4 kD). Tight junction and adherence junction proteins were imaged with immunofluorescence staining. Expression of Toll-like receptors (TLR) and inflammatory cytokines were measured in loop ileostomy takedowns in a second group of patients.

RESULTS

Because TER increased with patient age (P < .01), results were stratified into infant versus teenage groups. Fed bowel had significantly greater TER versus unfed bowel (P < .05) in both age populations. Loss of EBF was also observed by an increase in FITC-dextran permeation in enteral nutrient-deprived segments (P < .05). Immunofluorescence staining showed marked declines in intensity of ZO-1, occludin, E-cadherin, and claudin-4 in unfed intestinal segments, as well as a loss of structural formation of tight junctions. Analysis of cytokine and TLR expression showed significant increases in tumor necrosis factor (TNF)-α and TLR4 in unfed segments of bowel compared with fed segments from the same individual.

CONCLUSION

EBF declined in unfed segments of human small bowel. This work represents the first direct examination of EBF from small bowel derived from nutrient-deprived humans and may explain the increased incidence of infectious complications seen in patients not receiving enteral feeds.

Immunonutrition stimulates immune functions and antioxidant defense capacities of leukocytes in radiochemotherapy-treated head & neck and esophageal cancer patients: A double-blind randomized clinical trial

BACKGROUND

Immunonutrition has been reported to improve the immune status of perioperative cancer patients, thereby reducing complications and length of hospital stay.

AIM

This study aimed to assess whether immunonutrition enriched in arginine, EPA & DHA and nucleotides could impact the immune cells responses in head & neck and esophageal cancer patients treated by radiochemotherapy (RCT).

METHODS

A double-blind clinical trial was carried out in 28 patients randomized into two groups, receiving either an immunomodulating enteral nutrition formula (IEN, n = 13, Impact(®), Nestlé) or an isoenergetic isonitrogenous standard enteral nutrition formula (SEN, n = 15) throughout RCT (5-7 weeks). After isolation from whole blood, immune cells metabolism and functions were assessed at the beginning (Db) and at the end (De) of RCT.

RESULTS

Immunonutrition maintained CD4(+)/CD8(+) T-lymphocyte counts ratio and CD3 membrane expression between Db and De. Polymorphonuclear cells CD62L and CD15 densities and ROS production were increased in IEN patients. Peripheral blood mononuclear cells (PBMC) production of pro-inflammatory prostaglandin-E2 was stable in IEN patients and lower than in SEN patients at De. Genes coding for immune receptors, antioxidant enzymes and NADPH oxidase subunits were overexpressed in the PBMC of IEN vs SEN patients at De.

CONCLUSION

Immunonutrition can enhance immune cell responses through the modulation of their phenotypes and functions. By modulating the gene expression of immune cells, immunonutrition could make it easier for the organism to adapt to the systemic inflammation and oxidative stress induced by RCT.

CLINICAL TRIAL REGISTRATION

This clinical trial has been registered on ClinicalTrial.gov website: NCT00333099.

Lack of preoperative enteral nutrition reduces gut-associated lymphoid cell numbers in colon cancer patients: a possible mechanism underlying increased postoperative infectious complications during parenteral nutrition

OBJECTIVE

To examine preoperative dietary influences on gut-associated lymphoid tissue (GALT) cell number in the context of postoperative infectious complications.

BACKGROUND

There is little clinical evidence regarding whether nutritional routes affect GALT size and/or phenotype. The influence of GALT atrophy on clinical outcomes is also unclear.

METHOD

Patients with complete obstruction of the colon due to a tumor were excluded from this study. Study 1. Resected terminal ileum specimens, from 62 patients [preoperative parenteral nutrition (PN): n = 15, preoperative oral feeding (OF): n = 47] who underwent right colectomy during the period from 1997 to 2004 at our department, were immunohistochemically stained for counting numbers of T, IgA-producing, and mature and immature dendritic cells (DCs) in the lamina propria (LP) and intraepithelial space.Study 2. We reviewed 341 patients (PN: n = 99, OF: n = 242) with colon cancer who underwent colectomy during this period for postoperative complications.

RESULTS

Study 1. T cell numbers in the LP and intraepithelial space and IgA-producing cell number in the LP were significantly lower in the PN than in the OF group. Mature DC number in the LP was significantly lower in the PN than in the OF group, whereas total DC numbers (both mature and immature DC) were similar in the 2 groups.Study 2. The PN group had significantly higher rates of total infectious complications, surgical site infection, pneumonia, infectious colitis, and central venous catheter infection.

CONCLUSIONS

Lack of enteral delivery of nutrients reduces numbers of T and IgA-producing cells, as well as mature DCs, in GALT of colon cancer patients, as it does in animal models. A close association between GALT changes and infectious complication morbidity was confirmed.

Immunonutrition: Role in Wound Healing and Tissue Regeneration

Significance: The role of immunonutrition in wound healing has been an area of both interest and controversy for many years. Although deficiencies in certain nutrients have long been known to impair healing, supplementation of specific immune modulating nutrients has not consistently yielded improvements in wound healing. Still, the prospect of optimizing nutrition to assist the immune system in wound repair bears great significance in both medical and surgical fields, as the costs of wound care and repair cannot be ignored. Recent Advances: Recent studies have rekindled efforts to elucidate the roles of specific immunonutrients, and we now have a better understanding of the conditionally essential role of various nutrients such as arginine, which becomes essential in certain clinical situations such as for the trauma patient or patients at high risk for malnutrition. Immunonutrition in its current formulation usually includes supplementation with arginine, glutamine, omega-3 fatty acids, vitamins, and trace minerals, and its use has often been associated with decreased infectious complications and sometimes with improvements in wound healing. Critical Issues: A key to understanding the role of immunonutrition in wound healing is recognizing the distinct contributions and importance of the various elements utilized. Future Directions: Critical areas for future study include identifying the specific populations, timing, and ideal composition of immunomodulating diets in order to optimize the wound healing process.

A systems biology approach to nutritional immunology - focus on innate immunity

Innate immunity and nutrient metabolism are complex biological systems that must work in concert to sustain and preserve life. The effector cells of the innate immune system rely on essential nutrients to generate energy, produce metabolic precursors for macromolecule biosynthesis and tune their responses to infectious agents. Thus disruptions to nutritional status have a substantial impact on immune competence and can result in increased susceptibility to infection in the case of nutrient deficiency, or chronic inflammation in the case of over-nutrition. The traditional, reductionist methods used in the study of nutritional immunology are incapable of exploring the extremely complex interactions between nutrient metabolism and innate immunity. Here, we review a relatively new analytical approach, systems biology, and highlight how it can be applied to nutritional immunology to provide a comprehensive view of the mechanisms behind nutritional regulation of the innate immune system.

Nutrition and gut immunity

The human intestine contains huge amounts of nonpathologic bacteria surviving in an environment that is beneficial to both the host and the bacterial populations. When short pauses in oral intake occur with minimal alterations in the mucosa-microbial interface, critical illness, with its attendant acidosis, prolonged gastrointestinal tract starvation, exogenous antibiotics, and breakdown in mucosal defenses, renders the host vulnerable to bacterial challenge and also threatens the survival of the bacteria. This review examines the altered innate and adaptive immunologic host defenses that occur as a result of altered oral or enteral intake and/or injury.

Dose effects of chronically infused nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester on anabolic response and arginine metabolism in rats with subacute peritonitis

Nitric oxide synthase (NOS) inhibitors alleviate the adverse effects of nitric oxide (NO) overproduction that occurs during peritonitis, a clinical condition that is accompanied by arginine deficiency. However, the variations in the disease severity and the dosage, route, and period of NOS inhibitor administration are debatable. Therefore, we investigated the dose effects of chronically infused NOS inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME) on the anabolism, inflammatory responses, and arginine metabolism in parenterally fed rats with cecal puncture-induced subacute peritonitis. Male Wistar rats were divided into 4 groups and were administered total parenteral nutrition solutions with 0, 5 (low dose), 25 (medium dose), or 50 (high dose) mg·kg(-1)·d(-1) of L-NAME for 7 d. Sham-operated rats administered total parenteral nutrition solution and normal healthy rats fed chow diet were also included. Our results showed that parenteral infusion significantly decreased body weight gain and plasma citrulline concentrations. In rats with subacute peritonitis, the parenteral infusion-induced increases in circulating white blood cells and NO were significantly decreased, whereas the decrease in serum albumin levels was significantly increased. Rats with subacute peritonitis that were administered chronic infusion of L-NAME had a significantly reduced nitrogen balance. In addition, rats administered the medium dose of L-NAME had significantly increased plasma arginine, ornithine, glutamate, and proline. In conclusion, chronic infusion of NOS inhibitors may not alter systemic NO homeostasis and inflammatory response but may facilitate the production of arginine-associated amino acids and nitrogen excretion in cases of subacute peritonitis.