Impact of the feeding route on gut mucosal immunity

PURPOSE OF REVIEW

Enteral nutrition is recommended as a standard nutritional therapy in clinical settings. The rationale behind enteral nutrition may be decreased infectious morbidities compared with parenteral nutrition. However, the mechanism may not be well understood.

RECENT FINDINGS

Animal studies have revealed that enteral nutrition, compared with parenteral nutrition, preserves the gut-associated lymphoid tissue mass and function with well controlled gut cytokine milieu and intracellular signaling pathway, leading to the maintenance of intestinal and extraintestinal acquired mucosal immunity. Moreover, enteral nutrition can enhance the gut innate immunity by increasing the antimicrobial peptides, such as secretory phospholipase A2. More importantly, a recent clinical study demonstrated preoperative parenteral nutrition without enteral nutrition to decrease the number of T cells, IgA-producing cells, and mature dendritic cells in human terminal ileum, which are consistent with the data obtained from animal studies. Investigation of the mechanism has given us some surrogates of enteral nutrition during parenteral nutrition, such as glutamine, butyric acid, cytokines, and other mediators. However, to date, no surrogates can restore parenteral-nutrition-induced impairment of host defense completely.

SUMMARY

Because enteral nutrition is a practical way to preserve gut immunity, clinicians should make any efforts to shorten the period of enteral nutrition absence and increase the dose according to the degree of tolerance.

Influence of fish to soybean oil ratio on hepatic mononuclear cell function and survival after intraportal bacterial challenge in parenterally fed mice

BACKGROUND

Parenteral nutrition (PN) is indispensable for meeting the caloric and substrate needs of patients who cannot receive adequate amounts of enteral nutrition. However, PN decreases hepatic mononuclear cell (MNC) numbers and impairs their functions. We examined the effects of various ratios of ω-3 to ω-6 polyunsaturated fatty acids on hepatic MNC number and function in a murine model. We focused on serum liver enzymes, lipid metabolism, cytokine production, histopathology, and the outcomes of an intraportal bacterial challenge.

MATERIAL AND METHODS

In experiment 1, male Institute of Cancer Research mice were randomized to CHOW, 67%, 33%, 16%, 8%, 4%, and 0% fish oil (FO)-PN groups. After receiving their respective diets for 5 days, 1.0 × 10(7) Pseudomonas aeruginosa were delivered by intraportal injection. Survival was observed ≤ 7 days after injection. Liver histologies after intraportal bacterial challenge were examined in the CHOW, 33%, 8%, and 0% FO-PN groups. In experiment 2, the mice were divided into 4 groups: CHOW, 33%, 8%, and 0% FO-PN. After the mice had been fed for 5 days, MNC were isolated. Hepatic MNC were counted and cytokine productions (tumor necrosis factor [TNF]-α and interleukin [IL]-10) by MNC in response to lipopolysaccharide (LPS) were measured. Blood samples were analyzed for lipid metabolism and hepatobiliary biochemical parameters. Liver histologies were also examined.

RESULTS

In experiment 1, survival times were significantly shorter in the 4% and 0% FO-PN groups than in the CHOW group. Survival rates at 168 hours were 100%, 64%, 86%, 73%, 67%, 11%, and 13% in the CHOW, 67%, 33%, 16%, 8%, 4%, and 0% FO-PN groups, respectively. At 72 hours after intraportal bacterial challenge, the 0% FO-PN group showed severe tissue damage, whereas such damage was reduced in the 8% and 33% FO-PN groups. In experiment 2, the CHOW, 33%, 8%, and 0% FO-PN groups showed LPS dose-dependent increases in TNF-α levels. IL-10 levels were also LPS dose-dependently increased in the CHOW and 33% FO-PN groups. However, no marked changes were observed in response to LPS stimulation in either the 8% or the 0% FO-PN group. There were no differences in serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, or total bilirubin among these 4 groups. In the 0% FO-PN group, serum total cholesterol levels were greater than those in the 8% and 33% FO-PN groups. Without bacterial challenge, livers from the 0% FO-PN group showed steatosis, but these changes were attenuated in the 8% and 33% FO-PN groups.

CONCLUSION

The 30-40% ratio of FO to soybean oil with 20% of total calories supplied by lipid seems to be the best PN for preservation of hepatic MNC number and function.

Truncal vagotomy temporarily decreases the pro- and anti-inflammatory cytokine levels in the small intestine

PURPOSE

The vagus nerve exerts immunomodulatory functions by inhibiting pro-inflammatory cytokine overproduction. Because vagotomy is a standard procedure during the radical operation for esophageal or gastric cancer, the postoperative clinical course might be related to vagotomy-associated changes in the cytokine milieu. We herein examined the gut cytokine kinetics after vagotomy in mice.

METHODS

Thirty-eight male Institute of Cancer Research mice underwent sham or sub-diaphragmatic truncal vagotomy. The whole small intestine was harvested on postoperative day (POD) 14 (sham: vagotomy, n = 9:10) or 20 (n = 9:10). The pro- and anti-inflammatory cytokine levels in the plasma, jejunum, ileum and whole small intestine were evaluated.

RESULTS

The plasma cytokine levels were similar in the vagotomy and sham groups on POD 14 and 20. However, both the pro- and anti-inflammatory cytokine levels tended to be lower on POD 14 and higher on POD 20 in the vagotomy group than in the sham group. With regard to the cytokine kinetics, the jejunal IL-12p70, TNF-α, MCP-1 and IL-10, ileal IL-12p70, TNF-α, IL-6, MCP-1 and IL-10, and whole small intestinal IL-12p70, TNF-α, IFN-γ, MCP-1 and IL-10 of the vagotomy group all significantly increased on POD 20 as compared to POD 14.

CONCLUSION

Vagotomy has a major impact on the gut cytokine milieu. Vagotomy may initially inhibit both pro- and anti-inflammatory cytokine production, while both later increase.

Prevention of medical accidents caused by defective surgical instruments

BACKGROUND

The malfunctioning of surgical instruments may lead to serious medical accidents. Limited information is available on the risk of defective instruments. The purpose of these study is to demonstrate the features of defective surgical instruments, to establish a strategy to reduce the risk of medical accidents.

METHODS

We studied 19,474 consecutive operations during 2007 to 2009 at our hospital. The data on defective instruments were collected based on the orders for repair of broken instruments and reports of near-miss incidents. Adverse events caused by defective instruments were also identified from reports of near-miss incidents.

RESULTS

A total of 1,775 nonfunctioning instruments were identified during the study period. Of these, 112 were found during operation. More than half of the defective instruments were tissue-grasping instruments, bone-boring/gnawing instruments, and instruments for endoscopic surgery. Wearing out and inappropriate use of instruments were 2 major causes of defects. The rest of the causes consisted of inadequate inspection and factory defects. Two near-miss incidents (incidence 10 per 100,000 operations) in endoscopic surgery were potentially critical, but the postoperative course was uneventful in each patient. The incidence of defects adjusted by the number of operations demonstrated that bone-boring/gnawing instruments and instruments for endoscopic surgery tend to be broken during surgery. Without inspection by the manufacturer, the incidence would be much higher for endoscopic instruments.

CONCLUSION

Our data suggest that the appropriate use and adequate inspection of particular types of instruments are key for reducing the risk of medical accidents caused by defective surgical instruments.

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.

Effects of adding butyric acid to PN on gut-associated lymphoid tissue and mucosal immunoglobulin A levels

BACKGROUND

Parenteral nutrition (PN) causes intestinal mucosal atrophy, gut-associated lymphoid tissue (GALT) atrophy and dysfunction, leading to impaired mucosal immunity and increased susceptibility to infectious complications. Therefore, new PN formulations are needed to maintain mucosal immunity. Short-chain fatty acids have been demonstrated to exert beneficial effects on the intestinal mucosa. We examined the effects of adding butyric acid to PN on GALT lymphocyte numbers, phenotypes, mucosal immunoglobulin A (IgA) levels, and intestinal morphology in mice.

METHODS

Male Institute of Cancer Research mice (n = 103) were randomized to receive either standard PN (S-PN), butyric acid-supplemented PN (Bu-PN), or ad libitum chow (control) groups. The mice were fed these respective diets for 5 days. In experiment 1, cells were isolated from Peyer's patches (PPs) to determine lymphocyte numbers and phenotypes (αβTCR(+), γδTCR(+), CD4(+), CD8(+), B220(+) cells). IgA levels in small intestinal washings were also measured. In experiment 2, IgA levels in respiratory tract (bronchoalveolar and nasal) washings were measured. In experiment 3, small intestinal morphology was evaluated.

RESULTS

Lymphocyte yields from PPs and small intestinal, bronchoalveolar, and nasal washing IgA levels were all significantly lower in the S-PN group than in the control group. Bu-PN moderately, but significantly, restored PP lymphocyte numbers, as well as intestinal and bronchoalveolar IgA levels, as compared with S-PN. Villous height and crypt depth in the small intestine were significantly decreased in the S-PN group vs the control group, however Bu-PN restored intestinal morphology.

CONCLUSIONS

A new PN formula containing butyric acid is feasible and would ameliorate PN-induced impairment of mucosal immunity.

A new immune-modulating diet enriched with whey-hydrolyzed peptide, fermented milk, and isomaltulose attenuates gut ischemia-reperfusion injury in mice

BACKGROUND & AIMS

Gut ischemia-reperfusion (I/R) is considered an important mechanism underlying multiple organ failure after severe surgical insults. We previously demonstrated an enteral diet enriched with whey-hydrolyzed peptide, fermented milk, and isomaltulose to have anti-inflammatory effects in a concanavalin A-induced hepatitis model. Here, we investigated whether the immune-modulating diet (IMD), could prevent systemic inflammation, thereby improving survival in a gut I/R model.

METHODS

Mice were randomized into control enteral diet (n = 58) or IMD (n = 56) for 2 weeks' feeding. In experiment 1, 39 mice underwent 45 min of gut ischemia, and were sacrificed at 3 h after reperfusion to collect blood samples. Plasma IL-6 and glucose levels were measured. In experiment 2, 75 mice underwent 60 min of ischemia, and their survival was observed until 48 h.

RESULTS

Plasma IL-6 and glucose levels of the IMD group were significantly lower than those of control mice. In association with these changes, the IMD improved survival rate at early time points (12 and 30 h) after gut I/R (p < 0.05, χ(2) test).

CONCLUSIONS

Nutritional management with the IMD may be useful for preventing systemic inflammatory response after gut I/R.

Neutrophil elastase inhibitor restores gut ischemia reperfusion-induced impairment of gut immunity with reduced plasma interleukin-6 concentrations in mice

BACKGROUND AND PURPOSE

Gut-associated lymphoid tissue (GALT) is regarded as central mucosa-associated lymphoid tissue that influences systemic mucosal immunity. Our previous study revealed that gut ischemia and reperfusion (I/R) reduces GALT lymphocyte numbers. Because gut hypoperfusion frequently occurs in trauma, shock, and surgery patients, establishment of a therapeutic method to preserve GALT mass after gut I/R may be important for the prevention of infections. We examined the effects of sivelestat sodium hydrate, a selective inhibitor of neutrophil elastase, on GALT mass and plasma cytokine concentrations in a murine gut I/R model.

METHODS

Seventy male ICR mice were randomized to the control (n = 34) or the sivelestat (n = 36) group. After intravenous cannulation of the animals, the superior mesenteric artery was occluded for 60 min. After reperfusion, physiologic saline or sivelestat 5 mg/kg hourly was infused for 24 h. Sixteen mice in the control and 22 in the sivelestat group were alive at 24 h. Twenty-six mice (n = 13 in each group) were chosen randomly for harvest of the small intestine. Lymphocytes from Peyer patches (PP), the intraepithelial space (IE), and the lamina propria (LP) were counted; and their phenotypes (αβT-cell receptor (TCR), γδTCR, CD4, CD8, B cell) were determined by flow cytometry. Cytokine concentrations (interleukin [IL]-6, IL-1β, IL-10) in the plasma and bronchoalveolar lavage fluid were measured by enzyme-linked immunosorbent assay.

RESULTS

Sivelestat treatment did not improve survival but increased PP and IE lymphocyte numbers significantly and reduced the LP CD8(+) cell percentage and plasma IL-6 concentration compared with controls. There were no significant differences between the two groups in other cell phenotypes or cytokine concentrations.

CONCLUSION

Sivelestat treatment after gut I/R may be useful for maintaining gut immunity and preventing systemic inflammatory responses.

[A case of giant advanced ulcerative breast cancer managed with epirubicin and cyclophosphamide followed by weekly paclitaxel]

We report a case of giant advanced breast cancer with skin ulceration and bleeding (T4cN3M0, Stage IIIC) in which a significant QOL improvement was achieved with epirubicin and cyclophosphamide (EC) followed by weekly paclitaxel. A 63- year-old postmenopausal woman presented in May 2008 with a giant ulcerated right breast tumor and extensive erythema of the involved skin. She had discovered the tumor the previous year, but had not sought medical advice or treatment. A core needle biopsy of the breast mass led to a diagnosis of an invasive ductal carcinoma negative for estrogen receptor, progester-one receptor, and HER2/neu protein expression. She received q3w 4 cycles of EC(E: 60 mg/m(2), C: 600 mg/m(2))and 12 cycles of weekly paclitaxel (80 mg/m(2)). Upon completion of this chemotherapy, the breast tumor and skin erythema had nearly disappeared. A mastectomy was then performed with partial resection of the muscle and axillary lymph node dissection. Pathological examination showed only focal residual tumor cells and complete disappearance of cancer cells in the lymph nodes (Grade 2). EC followed by weekly paclitaxel therapy was effective for the locally advanced ulcerative breast tumor, and significantly improved QOL in this patient with Stage III C advanced breast cancer.

Enteral refeeding rapidly restores PN-induced reduction of hepatic mononuclear cell number through recovery of small intestine and portal vein blood flows

BACKGROUND

Absence of enteral nutrition (EN) reduces hepatic mononuclear cell (MNC) numbers and impairs their functions. However, enteral refeeding (ER) for as little as 12 hours following parenteral nutrition (PN) rapidly restores hepatic MNC numbers. We hypothesized that changes in small intestine and portal vein blood flows related to feeding route might be responsible for this phenomenon.

METHODS

In experiment 1, mice (n = 19) were randomized to Chow (n = 5), PN (n = 7) or ER (n = 7) groups. The Chow group was given chow ad libitum with intravenous (IV) saline for 5 days. The PN group was fed parenterally for 5 days, while the ER group was re-fed with chow for 12 hours following 5 days of PN. Then, small intestine and portal vein blood flows were monitored and hepatic MNCs were isolated and counted. In experiment 2, the effects of intravenous administration of prostaglandin E(1) (PGE(1)) on hepatic MNC numbers were examined in fasted mice for 12 hours. Mice (n = 28) were randomized to Control (n = 8), PG0 (n = 10), or PG1 (n = 10) groups. The Control group was fed chow ad libitum with IV saline, while the PG0 and PG1 groups were fasted for 12 hours with infusions, respectively, of saline and PGE(1) at 1 microg/kg/minute. Blood flows and hepatic MNC numbers were examined.

RESULTS

Experiment 1: ER restored PN-induced reductions in small intestine and portal vein blood flows and hepatic MNC number to the levels in the Chow group. Small intestine and portal vein blood flows correlated positively with hepatic MNC number. Experiment 2: Fasting decreased small intestine and portal vein blood flows and hepatic MNC number. However, PGE(1) restored portal vein blood flow to the level of the Control group, and moderately increased hepatic MNC number. There was a positive correlation between portal blood flow and hepatic MNC number.

CONCLUSIONS

Reduced small intestine and portal vein blood flows may contribute to impaired hepatic immunity in the absence of EN. ER quickly restores hepatic MNC number through recovery of blood flow in both the small intestine and the portal vein.

Enteral nutrition rapidly reverses total parenteral nutrition-induced impairment of hepatic immunity in a murine model

BACKGROUND & AIMS

Total parenteral nutrition (TPN) impairs host immunocompetence, a mechanism possibly underlying the high morbidity of infectious complications in critically ill patients. Our recent study demonstrated TPN to reduce the number and function of hepatic mononuclear cells (MNCs) and to worsen survival after intraportal Pseudomonas challenge in mice. The present study examined the duration of enteral nutrition (EN) needed to reverse TPN-induced changes in hepatic MNCs in a murine model.

METHODS

Male ICR mice (6 weeks) received 5 days of TPN followed by 0 (TPN), 12 (EN12), 24 (EN24), 48 (EN48) or 72 (EN72)h of chow feeding. Control mice (Control) were given chow with intravenous saline infusions for 5 days. After nutritional support, hepatic MNCs were isolated and counted. Lipopolysaccharide (LPS) receptor expressions (CD14 and TLR4/MD2) on Kupffer cells were analyzed by flowcytometry. In addition, TPN, EN12, EN48 and control mice were given intraportal Pseudomonas challenge and survival was monitored.

RESULTS

The TPN group was significantly lower in hepatic MNC number and LPS receptor expressions than the Control group. However, EN quickly reversed TPN-induced hepatic impairments in MNC loss within 12h, CD14 expression within 48 h and TLR4/MD2 expression within 24h. Survival of the EN48 group was significantly improved as compared with the TPN and EN12 groups.

CONCLUSIONS

EN rapidly reverses TPN-induced impairment of hepatic immunity along with increased hepatic MNC numbers and LPS receptor expressions on Kupffer cells.

Expression of centromere protein F (CENP-F) associated with higher FDG uptake on PET/CT, detected by cDNA microarray, predicts high-risk patients with primary breast cancer

BACKGROUND

Higher standardized uptake value (SUV) detected by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) correlates with proliferation of primary breast cancer. The purpose of this study is to identify specific molecules upregulated in primary breast cancers with a high SUV and to examine their clinical significance.

METHODS

We compared mRNA expression profiles between 14 tumors with low SUVs and 24 tumors with high SUVs by cDNA microarray. We identified centromere protein F (CENP-F) and CDC6 were upregulated in tumors with high SUVs. RT-PCR and immunohistochemical analyses were performed to validate these data. Clinical implication of CENP-F and CDC6 was examined for 253 archival breast cancers by the tissue microarray.

RESULTS

The relative ratios of CENP-F and CDC6 expression levels to beta-actin were confirmed to be significantly higher in high SUV tumors than in low SUV tumors (p = 0.027 and 0.025, respectively) by RT-PCR. In immunohistochemical analysis of 47 node-negative tumors, the CENP-F expression was significantly higher in the high SUV tumors (74%) than the low SUV tumors (45%) (p = 0.04), but membranous and cytoplasmic CDC6 expressions did not significantly differ between both groups (p = 0.9 each). By the tissue microarray, CENP-F (HR = 2.94) as well as tumor size (HR = 4.49), nodal positivity (HR = 4.1), and Ki67 (HR = 2.05) showed independent impact on the patients' prognosis.

CONCLUSION

High CENP-F expression, correlated with high SUV, was the prognostic indicators of primary breast cancer. Tumoral SUV levels may serve as a pretherapeutic indicator of aggressiveness of breast cancer.

Utility of 18F-fluoro-deoxyglucose emission tomography/computed tomography fusion imaging (18F-FDG PET/CT) in combination with ultrasonography for axillary staging in primary breast cancer

Background

Accurate evaluation of axillary lymph node (ALN) involvement is mandatory before treatment of primary breast cancer. The aim of this study is to compare preoperative diagnostic accuracy between positron emission tomography/computed tomography with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG PET/CT) and axillary ultrasonography (AUS) for detecting ALN metastasis in patients having operable breast cancer, and to assess the clinical management of axillary ¹⁸F-FDG PET/CT for therapeutic indication of sentinel node biopsy (SNB) and preoperative systemic chemotherapy (PSC).

Methods

One hundred eighty-three patients with primary operable breast cancer were recruited. All patients underwent ¹⁸F-FDG PET/CT and AUS followed by SNB and/or ALN dissection (ALND). Using ¹⁸F-FDG PET/CT, we studied both a visual assessment of ¹⁸F-FDG uptake and standardized uptake value (SUV) for axillary staging.

Results

In a visual assessment of ¹⁸F-FDG PET/CT, the diagnostic accuracy of ALN metastasis was 83% with 58% in sensitivity and 95% in specificity, and when cut-off point of SUV was set at 1.8, sensitivity, specificity, and accuracy were 36, 100, and 79%, respectively. On the other hand, the diagnostic accuracy of AUS was 85% with 54% in sensitivity and 99% in specificity. By the combination of ¹⁸F-FDG PET/CT and AUS to the axilla, the sensitivity, specificity, and accuracy were 64, 94, and 85%, respectively. If either ¹⁸F-FDG PET uptake or AUS was positive in allixa, the probability of axillary metastasis was high; 50% (6 of 12) in ¹⁸F-FDG PET uptake only, 80% (4 of 5) in AUS positive only, and 100% (28 of 28) in dual positive. By the combination of AUS and ¹⁸F-FDG PET/CT, candidates of SNB were more appropriately selected. The axillary ¹⁸F-FDG uptake was correlated with the maximum size and nuclear grade of metastatic foci (p = 0.006 and p = 0.03).

Conclusion

The diagnostic accuracy of ¹⁸F-FDG PET/CT was shown to be nearly equal to ultrasound, and considering their limited sensitivities, the high radiation exposure by ¹⁸F-FDG PET/CT and also costs of the examination, it is likely that AUS will be more cost-effective in detecting massive axillary tumor burden. However, when we cannot judge the axillary staging using AUS alone, metabolic approach of ¹⁸F-FDG PET/CT for axillary staging would enable us a much more confident diagnosis.

Influence of adding fish oil to parenteral nutrition on gut-associated lymphoid tissue

BACKGROUND

Lack of enteral nutrition reduces gut-associated lymphoid tissue (GALT) mass and function, a mechanism underlying the increased morbidity of infectious complications in severely injured or critically ill patients. Strategies to restore parenteral nutrition (PN)-induced changes of GALT mass and function have been pursued. However, the influences of adding fish oil to PN on gut immunity remain to be clarified.

METHODS

Male Institute of Cancer Research (ICR) mice (n = 50) were randomized to 4 groups: ad libitum chow (chow), fat free PN (fat (-)-PN), PN + fish oil (FO-PN), and PN + safflower oil (SO-PN). The PN groups were given isocaloric and isonitrogenous PN solutions. The FO- and SO-PN groups received 20% of total calories from fat emulsions. After 5 days of feeding, lymphocytes from Peyer's patches (PPs), the intraepithelial space (IE), and the lamina propria (LP) of the entire small intestine were isolated. GALT lymphocyte numbers and phenotypes (CD4+, CD8+, alphabetaTCR+, gammadeltaTCR+, B220+ cells) were determined. Immunoglobulin A (IgA) levels of small intestinal washings were also measured by enzyme-linked immunosorbent assay. Another set of mice (n = 24) was used to determine plasma fatty acid compositions after feeding.

RESULTS

Lymphocyte numbers from PPs and the LP and intestinal IgA levels were significantly lower in the PN groups than in the chow group, with no significant differences between any 2 PN groups. The FO- and SO-PN groups showed moderate recovery of IE cell numbers compared with the fat (-)-PN group. Omega-3 and omega-6 fatty acid levels were increased with fish and safflower oil additions, respectively, compared with the fat (-)-PN group.

CONCLUSIONS

Adding fish oil to PN does not exacerbate PN-induced GALT changes but rather partially reverses these changes, with increased plasma omega-3 fatty acid levels.

Intraluminal Glutamine Administration During Ischemia Worsens Survival After Gut Ischemia-Reperfusion

BACKGROUND

Glutamine (GLN) treatment prior to gut ischemia-reperfusion (I/R) reportedly preserves gut glutathione levels and gut barrier function. We hypothesized that intraluminal GLN during ischemia would also protect against gut I/R.

MATERIAL AND METHODS

After randomization to control and GLN groups, mice were exposed to 75 min (Exp 1) or 50 min (Exp 2 and 3) gut I/R. One mL of 2% GLN solution was injected into the duodenal lumen at the onset of ischemia in the GLN group, whereas controls were given normal saline. In experiment 1, survival was monitored for 120 h (n = 38). In experiment 2, blood, small intestine, and liver samples were collected at 4 h after reperfusion (n = 13). Expressions of CD11a and CD11b on myeloid cells were measured. Reactive oxygen intermediate production by myeloid cells was determined with or without phorbol myristate acetate stimulation. Glutathione levels in the small intestine and liver were also evaluated. In experiment 3, hemodynamic parameters were measured before and after I/R (n = 6).

RESULTS

In experiment 1, survival time in the GLN group was reduced compared with the control group. In experiment 2, GLN increased expression of CD11b and reactive oxygen intermediate with phorbol myristate acetate, compared with controls. There were no significant differences in gut or liver glutathione levels between the two groups. In experiment 3, the GLN group showed a transient but significant reduction in systolic blood pressure after reperfusion compared with the control group.

CONCLUSION

Intraluminal GLN during severe gut ischemia worsens outcomes, possibly by enhancing circulating myeloid cell priming and activation, and by disturbing hemodynamics, without increasing organ glutathione levels.

Nutritional route affects ERK phosphorylation and cytokine production in hepatic mononuclear cells

OBJECTIVE

To clarify the influence of nutritional route on hepatic immunity in a murine model.

SUMMARY BACKGROUND DATA

Parenteral nutrition is disadvantageous for preventing infectious complications in critically ill and/or severely injured patients as compared with enteral nutrition. To date, lack of enteral nutrition has been demonstrated to impair mucosal immunity, gut barrier function, and the peritoneal defense system. However, influences of nutritional route on hepatic immunity, another important defense system against infection, have not been well studied.

METHODS

Male ICR mice were randomized to 3 groups: ad libitum chow (chow), intravenous (IV)-TPN and intragastric (IG)-TPN groups. The TPN groups were given isocaloric and isonitrogenous TPN solutions. After the mice had been fed for 5 days, hepatic mononuclear cells (MNCs) were isolated. Hepatic MNC numbers and functions (cytokine production, intracellular signaling, and LPS receptor expression) were determined. Moreover, 1.0 x 10 Pseudomonas aeruginosa were delivered by intraportal injection. Survival and histology were examined.

RESULTS

Hepatic MNC numbers were significantly lower in the IV-TPN group than in the chow and IG-TPN groups, without subpopulation changes. As compared with enterally fed mice, cytokine production (TNF-alpha, IFN-gamma, and IL-10) by hepatic MNCs in response to LPS was impaired in parenterally fed mice in association with blunted phosphorylation of ERK1/2, a MAPK. Hepatic MNCs from IV-TPN mice showed decreased expressions of CD14 and TLR4/MD2, as compared with enterally fed mice. Survival times were reduced in the IV-TPN group as compared with the chow and IG-TPN groups.

CONCLUSION

Preservation of hepatic immunity with enteral feeding is important for prevention of infectious complications in severely injured and/or critically ill patients.

LACK OF ENTERAL NUTRITION BLUNTS EXTRACELLULAR-REGULATED KINASE PHOSPHORYLATION IN GUT-ASSOCIATED LYMPHOID TISSUE

The mitogen-activated protein kinase (MAPK) family (extracellular-regulated kinase [ERK], p38, etc.) of signal transduction proteins includes important intracellular mediators of inflammation, playing critical roles in host defense. Phosphorylations of ERK and p38 are responsible for cell proliferation, cell differentiation, and cell death. We hypothesized that impaired gut-associated lymphoid tissue (GALT) function in the absence of enteral nutrition is associated with reduced MAPK phosphorylation in GALT cells. Fifty-three male Institute of Cancer Research mice were randomized into 3 groups; ad libitum chow, intragastric (i.g.)-TPN, and intravenous (i.v.)-TPN. TPN groups were administered a standard TPN solution. After 5 days of feeding, lymphocytes from Peyer patches (PPs), the lamina propria (LP) cells, and intraepithelial (IE) spaces in the small intestine were isolated. GALT lymphocyte numbers were determined. The lymphocytes were incubated with or without 50 ng/mL of phorbol myristate acetate (PMA) for 15 min, and phosphorylated ERK (p-ERK) and p38 (p-p38) levels were determined using laser scanning cytometry. In PP (GALT inductive site) lymphocytes, p-ERK was increased after PMA in all three groups. However, ERK phosphorylation in GALT effector sites (IE and LP) was enhanced only in the enteral groups. p38 phosphorylation was not increased in any GALT sites, in any of the three groups, in response to PMA. In another set of mice (n = 33), in vitro LP lymphocyte proliferation was assessed with BrdU with or without PMA. Cell proliferation was increased or maintained at high level with PMA in the i.g.-TPN and chow group, but remained low in the i.v.-TPN group. In conclusion, lack of enteral feeding blunts ERK activation and cell proliferation in response to PMA stimulation in GALT effector sites, which may be an important mechanism underlying reduced GALT function. The influence of nutrition on GALT p38 phosphorylation must be assessed with other types and dosages of stimulants.

Influences of long-term antibiotic administration on Peyer's patch lymphocytes and mucosal immunoglobulin A levels in a mouse model

BACKGROUND

Long-term antibiotic administration is sometimes necessary to control bacterial infections during the perioperative period. However, antibiotic administration may alter gut bacterial flora, possibly impairing gut mucosal immunity. We hypothesized that 1 week of subcutaneous (SC) antibiotic injections would affect Peyer's patch (PP) lymphocyte numbers and phenotypes, as well as mucosal immunoglobulin A (IgA) levels.

METHODS

Sixty-one male Institute of Cancer Research mice were randomized to CMZ (cefmetazole 100 mg/kg, administered SC twice a day), IPM (imipenem/cilastatin 50 mg/kg x 2), and control (saline 0.1 mL x 2) groups. After 7 days of treatment, the mice were killed and their small intestines removed. Bacterial numbers in the small intestine were determined using sheep blood agar plates under aerobic conditions (n = 21). PP lymphocytes were isolated to determine cell numbers and phenotypes (CD4, CD8, alphabetaTCR, gammadeltaTCR, B220; n = 40). IgA levels in the small intestinal and bronchoalveolar washings were also measured with ELISA.

RESULTS

Antibiotic administration decreased both bacterial number and the PP cell yield compared with the control group. There were no significant differences in either phenotype percentages or IgA levels at any mucosal sites among the 3 groups.

CONCLUSIONS

Long-term antibiotic treatment reduces PP cell numbers while decreasing bacterial numbers in the small intestine. It may be important to recognize changes in gut mucosal immunity during long-term antibiotic administration.

Albumin infusion after reperfusion prevents gut ischemia-reperfusion-induced gut-associated lymphoid tissue atrophy

BACKGROUND

Our recent study clarified that gut ischemia-reperfusion (I/R) causes gut-associated lymphoid tissue (GALT) mass atrophy, a possible mechanism for increased morbidity of infectious complications after severe surgical insults. Because albumin administration reportedly reduces hemorrhagic shock-induced lung injury, we hypothesized that albumin treatment prevents GALT atrophy due to gut I/R.

METHODS

Male mice (n = 37) were randomized to albumin, normal saline, and sham groups. All groups underwent jugular vein catheter insertion. The albumin and normal saline groups underwent 75-minute occlusion of the superior mesenteric artery. During gut ischemia, all mice received normal saline infusions at 1.0 mL/h. The albumin group was given 5% bovine serum albumin in normal saline at 1.0 mL/h for 60 minutes after reperfusion, whereas the normal saline group received 0.9% sodium chloride at 1.0 mL/h. The sham group underwent laparotomy only. Mice were killed on day 1 or 7, and the entire small intestine was harvested. GALT lymphocytes were isolated and counted. Their phenotypes (alphabetaTCR, gammadeltaTCR, CD4, CD8, B220) were determined by flow cytometry.

RESULTS

On day 1, the gut I/R groups showed significantly lower total lymphocyte and B cell numbers in Peyer's patches and the lamina propria than the sham group. However, the albumin infusion partially but significantly restored these cell numbers. On day 7, there were no significant differences in any of the parameters measured among the 3 groups.

CONCLUSIONS

Albumin infusion after a gut ischemic insult may maintain gut immunity by preventing GALT atrophy.

Potential crosstalk between insulin-like growth factor receptor type 1 and epidermal growth factor receptor in progression and metastasis of pancreatic cancer

The insulin-like growth factor receptor type 1 (IGF1R) and epidermal growth factor receptor (EGFR) are reportedly overexpressed in pancreatic cancer. However, the correlation between activated EGFR and IGF1R and their clinicopathological implications still remain unclear. The cellular localization and overexpression of IGF1R and EGFR were investigated immunohistochemically in primary invasive ductal pancreatic carcinomas obtained from 74 patients who underwent radical surgical resection. We also compared the status of IGF1R and EGFR overexpression between primary tumors and hepatic metastatic tumors obtained from 44 autopsied patients. Among the 74 surgically resected primary tumors, cytoplasm- and membrane-dominant EGFR overexpression was detected in 22 (30%) and 7 (9%), respectively, whereas cytoplasm- and membrane-dominant IGF1R overexpression was detected in 8 (11%) and 28 (38%), respectively. Membrane-dominant EGFR and cytoplasm-dominant IGF1R were more frequent in lower-grade tumors and correlated with favorable prognosis, whereas cytoplasm-dominant EGFR and membrane-dominant IGF1R were more frequent in higher-grade tumors and correlated with poor prognosis. In 36 autopsy specimens of pancreatic tumor with concurrent overexpression of IGF1R and EGFR, there was an inverse correlation between the IGF1R and EGFR localization patterns (P = 0.001). In the hepatic metastatic tumors obtained by autopsy, the incidences of both IGF1R and EGFR overexpression were much higher than in the surgically resected primary tumors. More than half of the autopsy cases consistently showed membrane-dominant EGFR expression in both the primary tumor and hepatic metastases, whereas IGF1R expression showed considerable variation. Crosstalk between differently localized IGF1R and EGFR might play a role in determining the biological aggressiveness of pancreatic cancer, although their cellular localization may often alter during the process of metastasis.

High-level Skp2 expression in pancreatic ductal adenocarcinoma: correlation with the extent of lymph node metastasis, higher histological grade, and poorer patient outcome

OBJECTIVES

Recent studies have shown that overexpression of S-phase kinase-associated protein 2 (Skp2) occurs in many cancers at an advanced stage. We examined the clinicopathologic significance and prognostic implication of Skp2 expression in pancreatic invasive ductal carcinoma.

METHODS

Tissue samples from 46 pancreatic carcinomas were examined immunohistochemically for Skp2. The proportion of constituent tumor cells with Skp2 expression was analyzed and classified as high-level nuclear expression when more than 20% of the cancer cells were positive, or low-level nuclear expression otherwise.

RESULTS

High-level Skp2 overexpression was detected in 13 (28.3%) of the 46 tumors. The incidence of high-level Skp2 was correlated with higher histological grade (P = 0.0056), the extent of lymph node metastasis (P = 0.0086), the level of lymphatic permeation (P = 0.0024), and poorer patient outcome (P = 0.0189). Multivariate analysis showed that high-level Skp2 expression was an independent predictor of overall patient survival (P = 0.0140).

CONCLUSIONS

It is suggested that examination of Skp2 expression might be clinically useful for prognostication in patients with pancreatic carcinoma and that Skp2 protein might be a novel therapeutic molecular target.

Dietary restriction compromises resistance to gut ischemia-reperfusion, despite reduction in circulating leukocyte activation

BACKGROUND

Gut ischemia-reperfusion (gut I/R) accompanying severe surgical insults leads to neutrophil-mediated injury and is regarded as a triggering event in early multiple-organ failure. Our previous study demonstrated dietary restriction to down-regulate leukocyte activation. Therefore, we hypothesized dietary restriction might be beneficial in terms of surviving I/R. We also evaluated leukocyte activation and the level of organ glutathione, an antioxidative substance.

METHODS

Institute of Cancer Research mice received chow, 170 (ad libitum), 119 (MR: mild restriction) or 68 (SR: severe restriction) g/kg per day for 7 days. Exp. 1: The mice (n = 59) underwent 15 or 45 minutes of gut ischemia and survival was observed. Exp. 2: The mice (n = 73) were killed before or 60 or 120 minutes after 15-minute ischemia. Reactive oxygen intermediate (ROI) production by circulating myeloid cells and CD11b expression was determined. Some mice were assessed for nuclear factor kappa B (NFkappaB) activation. Glutathione levels were measured in some of the small intestine and liver samples from each group.

RESULTS

Dietary restriction decreased survival. Circulating myeloid cell priming and activation, in terms of ROI production and CD11b expression, were enhanced in the ad libitum group but not in the restricted groups. NFkappaB was activated only in the ad libitum group. Gut and hepatic glutathione levels were lower in the SR than in the ad libitum group. Dietary restriction caused histologic damages in gut, liver, and lung 120 minutes after reperfusion.

CONCLUSIONS

Dietary restriction blunts leukocyte priming and activation after gut ischemic insult but worsens the outcome by, at least in part, decreasing antioxidative activities. Clinically, nutrition replenishment may be required to improve the outcome of gut hypoperfusion.

Route and type of nutrition influence nuclear factor kappaB activation in peritoneal resident cells

Morbidity of intra-abdominal abscess is increased when severely injured patients are fed parenterally. Lack of enteral nutrition appears to impair peritoneal cavity host defense. Because the transcription factor nuclear factor kappaB (NFkappaB) regulates various genes involved in inflammatory responses and its activation is important for host defense, we hypothesized that enteral nutrition would preserve appropriate NFkappaB activation in peritoneal resident cells (PRCs), the first defense line against peritoneal contamination. Mice (n = 105) were randomized to chow (n = 38), intravenous (IV)-total parenteral nutrition (TPN) (n = 34), or intragastric (IG)-TPN (n = 33) for 5 days' feeding. In experiment 1, PRCs were harvested for measurement of intranuclear NFkappaB activity with or without in vitro lipopolysaccharide (LPS) stimulation using laser scanning cytometry and enzyme-linked immunoabsorbant assay. PRC numbers tended to be higher in enterally fed mice than in IV-TPN mice. The main PRC subpopulation was macrophages in all groups. NFkappaB activation was increased in response to LPS in chow mice, whereas there was no increase in the IV-TPN group. IG-TPN mice demonstrated moderate NFkappaB activation. In experiment 2, mice underwent cecal ligation and puncture (CLP). Survival was observed up to 5 days. In another set of mice, tumor necrosis factor (TNF) alpha levels of peritoneal lavaged fluid were measured 4 h after CLP. Survival times after CLP improved in the chow and IG-TPN groups compared with the IV-TPN group. TNFalpha levels were significantly higher in the chow than in the IV-TPN group. In conclusion, parenteral nutrition decreases PRC number and blunts NFkappaB activation in PRCs. These changes may impair host defense in the peritoneal cavity.

Gut ischemia-reperfusion affects gut mucosal immunity: A possible mechanism for infectious complications after severe surgical insults*

OBJECTIVE

To examine influences of gut ischemia/reperfusion (I/R) on gut-associated lymphoid tissue (GALT) mass and function.

DESIGN

Prospective, randomized controlled study.

SETTING

Research laboratory.

SUBJECTS

Male Institute of Cancer Research mice.

INTERVENTIONS

Ninety mice were randomized to three groups: I/R (60-min gut ischemia), sham (laparotomy only), and control (no operation). On days 1, 2, 4, 7, and 10, mice were killed to harvest lymphocytes from Peyer patches, the intraepithelial space, and the lamina propria (LP) of the small intestine. Respiratory tract and small intestinal washings were also obtained.

MEASUREMENTS AND MAIN RESULTS

Gut I/R significantly reduced lymphocyte numbers in Peyer patches, the intraepithelial space, and the LP. The reduction was prominent in GALT effector sites, that is, the intraepithelial space and LP, but numbers recovered quickly in LP. Changes in cell numbers in Peyer patches, GALT inductive sites, were subtle but persistent. Gut I/R reduced B cell numbers in Peyer patches; alphabeta T cell receptor (TCR)+, gammadeltaTCR+, CD8+, and B cell numbers in the intraepithelial space; and gammadeltaTCR+, CD8+, and B cell numbers in the LP, in comparison with the sham or control group. There were no significant differences in respiratory tract immunoglobulin A levels between the I/R and sham groups. Intestinal immunoglobulin A was elevated on day 1 in the I/R group, with no significant difference after day 2 in comparison with the sham group.

CONCLUSIONS

Despite the maintained mucosal immunoglobulin A level, gut I/R markedly reduces GALT cell numbers, with changes in lymphocyte phenotypes. These alterations may be associated with increased morbidity due to infectious complications after severe surgical insults.

EXOGENOUS INTERLEUKIN 7 AFFECTS GUT-ASSOCIATED LYMPHOID TISSUE IN MICE RECEIVING TOTAL PARENTERAL NUTRITION

In the absence of enteral nutrient delivery, gut-associated lymphoid tissue (GALT) mass and function are reduced. The purpose of this study was to examine whether exogenous interleukin (IL)-7 treatment reverses intravenous (IV)-total parenteral nutrition (TPN)-induced changes in GALT, immunoglobulin (Ig) A levels, and gut barrier function. Eighty-nine mice were randomized to chow, TPN, or TPN + IL-7 (1 microg/kg, administered IV twice a day) and treated for 5 days. The entire small intestine was harvested and lymphocytes were isolated from Peyer's patches (PPs), intraepithelial (IE) spaces, and the lamina propria (LP). Small intestinal and bronchoalveolar IgA levels were measured. Proximal and distal small intestinal levels of IgA-stimulating (IL-10) and IgA-inhibiting (IFNgamma) cytokines were determined with enzyme-linked immunoabsorbant assay. Moreover, 1 x 10 live Pseudomonas aeruginosa were delivered by gavage and survival was observed. TPN decreased total cell yields from PPs, IE spaces, and the LP compared with the chow group. IL-7 treatment restored cell numbers. PP CD4+, PP CD8+, IE gammadeltaTCR+, and LP CD4+ cell numbers were higher in the TPN + IL-7 group than in the TPN group. Secretory IgA levels were lower in the TPN and TPN + IL-7 than in the chow group. In the distal small intestine, IFNgamma levels were similar in the three groups, whereas IL-10 levels were reduced in the TPN and TPN + IL-7 groups relative to the chow group. Survival times were reduced in the TPN compared with the chow group, but IL-7 treatment significantly improved survival. Thus, exogenous IL-7 does not improve secretory IgA levels, nor are there any remarkable effects on levels of gut IgA-mediating cytokines. However, IL-7 treatment during TPN reverses TPN-induced GALT atrophy and improves survival in a gut-derived sepsis model.

T lymphocyte numbers in human gut associated lymphoid tissue are reduced without enteral nutrition

BACKGROUND

Clinically, in the absence of enteral nutrition, the morbidity of infectious complication is high. Although experiments using mice have shown alterations in gut-associated lymphoid tissue (GALT) to be an important mechanism underlying impaired host defense, there are no clinical studies on the effects of nutritional routes on GALT.

METHODS

A total of 27 colon cancer cases who underwent right colectomy or hemicolectomy were reviewed. Six patients did not receive enteral nutrition for 4 to 28 days before surgery because of bowel obstruction (parenteral nutrition [PNI group). Twenty-one patients were enterally fed before surgery (enteral nutrition [EN] group). The terminal ileum from resected specimens was examined microscopically. T-cell numbers in intraepithelial spaces (IE) and the lamina propria (LP) were determined immunohistochemically in blinded fashion.

RESULTS

There were no significant differences in baseline characteristics between the 2 groups. T-cell number in the LP was significantly lower in the PN group than in the EN group, with no difference in IE cell numbers.

CONCLUSIONS

Lack of enteral delivery of nutrients reduces GALT cell number in patients with colon cancer, as is the case in mice.

L-arginine-enriched parenteral nutrition affects lymphocyte phenotypes of gut-associated lymphoid tissue

BACKGROUND

Experimentally, total parenteral nutrition (TPN) diminishes gut-associated lymphoid tissue (GALT) cell numbers and function. Although glutamine supplementation is known to reverse TPN-induced changes in GALT, effects of another conditionally essential amino acid, L-arginine (ARG), on GALT remain unclear.

METHODS

Twenty-two male Institute of Cancer Research mice were randomized to standard TPN (0.3% arginine, STD-total parenteral nutrition) or 1% ARG-enriched TPN (ARG-total parenteral nutrition). After 5 days of feeding, lymphocytes were harvested from Peyer's patches (PP), the lamina propria, and intraepithelial (IE) spaces of the small intestine to determine cell yields. Lymphocyte phenotypes (alphabetaTCR, gammadeltaTCR, CD4, CD8, and B220 as a B cell marker) were determined using flow cytometry. IgA levels in washings of the small intestine, upper respiratory tract, and lungs were measured with ELISA.

RESULTS

ARG-total parenteral nutrition did not affect lymphocyte yields. The percentages of CD4+ cells in PP and IE, and alphabetaTCR+ cells in PP, were significantly higher in the ARG-total parenteral nutrition than in the STD-total parenteral nutrition mice, without marked differences in other phenotypes examined. There were no significant differences in intestinal and respiratory tract IgA levels between the 2 groups of mice.

CONCLUSIONS

One percent ARG supplementation of TPN does not improve GALT cell number or mucosal IgA level but benefits to increase CD4+ cell percentages in GALT.

Effects of L-arginine infusion during ischemia on gut blood perfusion, oxygen tension, and circulating myeloid cell activation in a murine gut ischemia/reperfusion model

BACKGROUND

Gut hypoperfusion is considered to be a mechanism for early multiple-organ failure after severe surgical insults. L-Arginine (ARG) may preserve gut microcirculation as a substrate of nitric oxide synthase, but simultaneously may enhance immune cell response. It remains unknown if ARG infusion during gut ischemia improves the outcome after gut ischemia-reperfusion (I/R).

METHODS

Male Institute of Cancer Research mice were randomized to control and ARG groups. After i.v. cannulation, mice underwent 90 (Exp. 1) or 60 (Exp. 2 and 3) minutes of gut I/R. Control mice received normal saline infusion at 1 mL/h for 60 minutes during ischemia, whereas the ARG group was given 1% ARG hydrochloride solution. In Exp. 1, survival was observed for 72 hours (n = 35). In Exp. 2, blood perfusion and oxygen tension of the small intestine were measured (n = 9). In Exp. 3, peripheral blood was obtained at 2 or 4 hours after reperfusion (n = 22). Reactive oxygen intermediate (ROI) production by myeloid cells with or without phorbol myristate acetate (PMA) stimulation and expression of CD11a and CD11b on myeloid cells were examined using flow cytometry.

RESULTS

Exp. 1: There was no significant difference in survival times (log rank test, p = .2). However, survival rates at 12 hours were 72% (13/18) for the control group and 35% (6/17) for the ARG group (p < .05 Fisher). Exp. 2: ARG infusion significantly improved gut blood perfusion ratio during ischemia but had no effect on oxygen tension. Exp. 3: In the ARG group, ROI production with PMA and CD11b expression at 4 hours were higher than those at 2 hours, whereas there were no significant changes in the control mice.

CONCLUSIONS

ARG infusion improves intestinal blood perfusion during ischemia but primes and activates circulating myeloid cells excessively. Consequently, i.v. infusion of ARG during ischemia reduces survival rate.

Vascular endothelial growth factor synthesis by human omental mesothelial cells is augmented by fibroblast growth factor-2: possible role of mesothelial cell on the development of peritoneal metastasis

Although peritoneal metastasis is an important factor determining the prognosis of patients with gastrointestinal cancer, the mechanisms have not yet been clearly defined. Human peritoneal mesothelial cells (HPMC) are the first line against disseminated tumor cells. Recent reports have shown that mesothelial cells are capable of secreting various cytokines and growth factors. In this study, we isolated human mesothelial cells from surgically resected omental tissue and examined the production and interaction of two major angiogenic factors, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2). Quiescent HPMC produced a considerable amount of VEGF at almost the same level as tumor cells. Interestingly, addition of FGF-2 to the culture significantly increased the mRNA synthesis and protein secretion of VEGF in a dose-dependent manner, as determined by Northern blot and ELISA. The addition of 0.5 ng/mL FGF-2 was enough to stimulate VEGF production, and the effect reached a plateau at 5 ng/mL. Reverse-transcribed polymerase chain reaction (RT-PCR) method clarified that the HPMC-derived VEGF consisted mostly of VEGF(121) and VEGF(165), which are both predominantly soluble forms. These data suggest that HPMC contribute to the development of metastases and the accumulation of malignant ascites due to the production of VEGF, especially in cancers that do not express enough amount of VEGF.

[Role of polymorphonuclear neutrophils and macrophages in the prevention of postoperative infections]

Polymorphonuclear neutrophils (PMNs) and macrophages are recognized to serve as the first line of defense against bacterial contamination during the perioperative period. Chemoattractants produced by macrophages cause PMN accumulation at the inflammatory site. Proinflammatory cytokines released by macrophages increase adhesion molecule expression on the surface of endothelial cells. P- and E-selectins produce leukocyte rolling, whereas beta 2-integrin-ICAM-1 interaction causes firm adhesion of leukocytes to the endothelium, followed by migration to the interstitium. Thus appropriate activation of the inflammatory cascade leads to leukocyte migration to the infectious focus. In particular, during the first several hours after the onset of bacterial contamination, massive exudation of PMNs is generally observed. PMNs and macrophages phagocytose the bacteria via opsonization and kill them with oxygen products or proteolytic enzymes. Malnutrition and the lack of enteral nutrition are assumed to impair PMN-macrophage-dependent host defense by derangement of adhesion molecule expression and the cytokine milieu. Recently, sticky PMNs before surgery have been reported to increase infectious morbidity after surgery. In addition, augmented alpha 4-integrin-VCAM-1 interaction has been demonstrated during sepsis, which is possibly a mechanism for increased PMN adhesion and resultant organ injury. Further study is needed to clarify the mechanisms of the disturbed function of PMNs and macrophages under various conditions.

Patients with postoperative infections have sticky neutrophils before operation

Appropriate polymorphonuclear neutrophil (PMN) recruitment is essential for host defense against infection. We investigated the significance of the preoperative PMN adhesion-migration process, as assessed by the flow chamber method, on postoperative infectious complications. Thirty-one consecutive patients with gastrointestinal malignancies, 21 colorectal and 10 gastric, who were undergoing elective surgery were enrolled. PMNs, isolated preoperatively from each patient's venous blood, were perfused onto a tumor necrosis factor alpha-stimulated human umbilical vein endothelial cell (HUVEC) monolayer through the flow chamber. We evaluated the adherent PMN number, the migrated PMN number, and the stuck PMN number by directly inspecting PMN interactions with a HUVEC monolayer under continuous shear flow simulating postcapillary venules. The expression of adhesion molecules on circulating PMNs was also measured. Patients were grouped into an infectious and a noninfectious group according to the occurrence of postoperative infectious complications defined by the Centers for Disease Control criteria. Eleven patients developed postoperative infectious complications. Although the number of preoperative in vitro adherent PMNs in patients with postoperative infection was significantly higher than in those without postoperative infection (P = 0.01), migrated PMN number was similar in both groups. Stuck PMN number tended to be higher in the infectious group than in the noninfectious group. The migrated PMN number showed a significant positive correlation with the adherent PMN number in the noninfectious group but not in the infectious group. Preoperative CD31 expression on circulating PMNs was significantly lower in the infectious group than in the noninfectious group. Preoperative in vitro derangement of the PMN adhesion-migration process is closely associated with postoperative infectious complications.

Brief refeeding rapidly reverses dietary restriction-induced nuclear factor-kappaB downregulation in peritoneal resident cells

BACKGROUND

Malnutrition impairs host immunity, resulting in high mortality and morbidity, secondary to infections. Nuclear factor kappaB (NFkappaB) plays a critical role in host defense, but how quickly refeeding normalizes the impaired NFkappaB activity in peritoneal resident cells (PRCs) is unknown. Our aim was to investigate the effects of 1-day ad libitum refeeding on severe diet restriction-induced NFkappaB activity in PRCs.

METHODS

Mice received chow, 146 g/kg per day (ad libitum) or 36.5 g/kg per day (severe diet restriction), for 7 days. One-half the mice in the diet-restricted group were then fed ad libitum for 1 day (refeeding). PRCs were harvested by peritoneal lavage. After incubation with tumor necrosis factor-alpha (TNF-alpha), nuclear translocation of NFkappaB in PRCs was investigated using laser scanning cytometry.

RESULTS

The main subpopulation of PRCs was macrophages in all groups. Mean fluorescence intensity over the nuclear area at 0 or 100 ng/mL of TNF-alpha was 16 +/- 2 or 31 +/- 8* in the ad libitum, 20 +/- 4 or 19 +/- 3 in the severe diet-restricted, and 20 +/- 4 or 30 +/- 5* in the refeeding group, respectively (*p < .05 versus 0 ng/mL of TNF-alpha in each group versus 100 ng/mL of TNF-alpha in diet-restricted group). Cytoplasmic accumulation of NFkappaB was significantly increased after TNF-alpha stimulation in the refed group but not in the ad libitum group.

CONCLUSIONS

The blunted NFkappaB activity in PRCs, after exposure to inflammatory stimuli, was restored after 1 day of refeeding, with increased accumulation of NFkappaB in the cytoplasm. Even brief nutritional replenishment in malnutrition may improve host defense by restoring NFkappaB activity and thereby improving macrophage functions.

Enteral feeding preserves mucosal immunity despite in vivo MAdCAM-1 blockade of lymphocyte homing

OBJECTIVE

To determine the influence of route of nutrition on gut mucosal addressin cellular adhesion molecule-1 (MAdCAM-1) expression and the effect of MAdCAM-1 blockade on gut-associated lymphoid tissue (GALT) lymphocyte populations and established respiratory antibacterial immunity.

SUMMARY BACKGROUND DATA

Lymphocytes, sensitized to antigens in Peyer's patches, migrate via mesenteric lymph nodes and home to intestinal lamina propria. MAdCAM-1 located on endothelial cells regulates this trafficking. Experimentally, parenteral nutrition (PN) decreases GALT cell mass and mucosal immunity when compared with enteral feeding.

METHODS

In experiment 1, MAdCAM-1 expression was quantified in 32 mice after 4 days of feeding chow, a complex diet, intragastric (IG)-PN, or PN. In experiment 2, MAdCAM-1 was measured in 102 mice 0, 4, 8, 12, 24, 48, or 72 hours after starting PN and at 0, 4, 8, 12, 24, or 48 hours after reinstituting chow following 5 days of PN. In experiment 3, 56 mice received chow, PN, chow + MECA-367 (anti-MAdCAM-1 mAb), or chow + Isotype control Ab (IsoAb) for 5 days, followed by Peyer's patches, lamina propria, and intraepithelial lymphocyte yield with respiratory and intestinal IgA levels. In experiment 4, 10 days after Pseudomonas immunization, mice received chow + MECA-367 or chow + IsoAb for 4 days followed by 1.2 x 108 Pseudomonas intratracheally.

RESULTS

Diet and route affect MAdCAM-1 expression (chow > complex diet > IG-PN > PN). Decreased MAdCAM-1 expression occurred within hours of starting PN in Peyer's patches, but not mesenteric lymph nodes or the intestine, and recovered quickly with enteral refeeding. MAdCAM-1 blockade reduced all GALT populations. Blockade had little effect on IgA levels and partially impaired the late response of established respiratory immunity.

CONCLUSIONS

Enteral feeding affects MAdCAM-1 expression. Complete MAdCAM-1 blockade reduces GALT lymphocytes to PN levels, but the chow feeding stimulus preserves IgA and early antibacterial resistance, implying the existence of non-MAdCAM-1 mechanisms to preserve mucosal immunity.