Inflammatory mediators and immune function are altered in home parenteral nutrition patients

Host-Gut Microbiota Crosstalk in Intestinal Adaptation

Short-bowel syndrome represents the most common cause of intestinal failure and occurs when the remaining intestine cannot support fluid and nutrient needs to sustain adequate physiology and development without the use of supplemental parenteral nutrition. After intestinal loss or damage, the remnant bowel undergoes multifactorial compensatory processes, termed adaptation, which are largely driven by intraluminal nutrient exposure. Previous studies have provided insight into the biological processes and mediators after resection, however, there still remains a gap in the knowledge of more comprehensive mechanisms that drive the adaptive responses in these patients. Recent data support the microbiota as a key mediator of gut homeostasis and a potential driver of metabolism and immunomodulation after intestinal loss. In this review, we summarize the emerging ideas related to host-microbiota interactions in the intestinal adaptation processes.

Home Parenteral Nutrition Support in Adults: Experience of a Medical Center in Asia

BACKGROUND

Parenteral nutrition (PN) support is mandatory in patients with gut failure. Short bowel syndrome is a term used for symptoms and pathophysiological disorders brought about by the removal or malfunction of a large portion of the small bowel. Inflammatory bowel disease, vascular disease, and malignancy are the most common causes of short bowel syndrome in adults. There are many complications associated with chronic use of PN. Cholestasis, nutrient deficiency, small bowel bacterial overgrowth, and catheter-related infections were noted in these patients. Due to the various etiologies, we tried to find the optimal method to manage these patients.

METHODS

We reviewed all patients over 16 years old, from 1989 to 2002, who required home PN support for at least 30 days. Charts were reviewed to obtain information regarding demographics, nutrition management, outcome, and complications related to PN. Survival was estimated by using the Kaplan-Meier method. The association of survival with primary disease, length of small bowel, age, and gender was assessed by proportional hazard regression analysis.

RESULTS

There were 31 patients who needed home PN support during this period, 14 male and 17 female. The average age was 55 (median age, 53; range, 28-88); the average period of PN administration was 19 months (median, 7; range, 1-115 months). The most common indications for home PN were alimentary tract obstruction and short bowel syndrome. Most deaths were related to their original diseases and catheter-related sepsis. Malignant diseases were a major indication for home PN (HPN). However, 20% of these patients with incurable diseases lived longer than 1 year. The disease patterns were different from those in western societies. Most patients had malignancies and vascular insults in our series. There was much less inflammatory bowel disease in our patients than in western countries; catheter-related infections were frequent and caused 25% of mortality.

CONCLUSIONS

HPN is very important to patients with intestinal failure or who are waiting for recovery from temporal intestine insufficiency. Even in malignant diseases, a significant number of patients survived for >1 year with treatment of HPN. Most complications related to their underlying diseases and associated infections. Improving patient education and treatment might improve the prognosis of these patients and expand the application of this technique to help more patients with small intestine failure.

Systemic Inflammatory Mediators and Bone Homeostasis in Intestinal Failure

BACKGROUND

A proinflammatory state has been described in patients with intestinal failure. The prevalence of metabolic bone disease in this group is considerable. It is not known whether this proinflammatory state is related to bone parameters, though bone disease is recognized as a proinflammatory process in postmenopausal women. The purpose of this study was to examine whether inflammation was related to bone disease.

METHODS

Eight patients with parenteral nutrition (PN)-dependent intestinal failure but no recent infections or immunosuppressive medications had serum assayed for interleukin-6 (IL-6), tumor necrosis factor (TNF)-alpha, and its receptors (TNFR-I and TNFR-II), C-reactive protein, and whole blood for lymphocyte proliferation. Routine clinical laboratory measures of vitamin D, parathyroid hormone, serum calcium, and phosphorus within 3 months of the inflammatory measures were compared by Pearson's correlation to the inflammatory measures.

RESULTS

Mean values for calcium, phosphorus, and albumin were normal, but 25-hydroxy vitamin D was reduced and parathyroid hormone and alkaline phosphatase elevated. Serum total calcium was negatively related to TNFR-II, TNF-alpha and positively to T-helper cells. Longer PN dependence was associated with inflammation and negatively with T-helper cells.

CONCLUSIONS

These preliminary findings are hypothesis generating only but support an association of low calcium and longer duration of PN with inflammation in patients with intestinal failure. Whether the inflammation results from vitamin D deficiency or the vitamin D deficiency develops secondary to excessive use of activated vitamin D to modulate inflammation from some other cause, such as a component of PN or repeated infectious challenge, requires further study.

A consideration of biomarkers to be used for evaluation of inflammation in human nutritional studies

To monitor inflammation in a meaningful way, the markers used must be valid: they must reflect the inflammatory process under study and they must be predictive of future health status. In 2009, the Nutrition and Immunity Task Force of the International Life Sciences Institute, European Branch, organized an expert group to attempt to identify robust and predictive markers, or patterns or clusters of markers, which can be used to assess inflammation in human nutrition studies in the general population. Inflammation is a normal process and there are a number of cells and mediators involved. These markers are involved in, or are produced as a result of, the inflammatory process irrespective of its trigger and its location and are common to all inflammatory situations. Currently, there is no consensus as to which markers of inflammation best represent low-grade inflammation or differentiate between acute and chronic inflammation or between the various phases of inflammatory responses. There are a number of modifying factors that affect the concentration of an inflammatory marker at a given time, including age, diet and body fatness, among others. Measuring the concentration of inflammatory markers in the bloodstream under basal conditions is probably less informative compared with data related to the concentration change in response to a challenge. A number of inflammatory challenges have been described. However, many of these challenges are poorly standardised. Patterns and clusters may be important as robust biomarkers of inflammation. Therefore, it is likely that a combination of multiple inflammatory markers and integrated readouts based upon kinetic analysis following defined challenges will be the most informative biomarker of inflammation.

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.

How immunocompromised are short bowel patients receiving home parenteral nutrition? Apropos a case of disseminated Fusarium oxysporum sepsis

BACKGROUND

Catheter-related sepsis is the most frequent complication in patients receiving home parenteral nutrition (HPN) for short bowel syndrome (SBS). A low-grade systemic inflammatory state and an altered mucosal immune response, as well as diminished intestinal barrier function have been characterized in these patients. The possibility of systemic immunocompromise has only recently been suggested.

CASE DESCRIPTION

A 45-year-old female with traumatic SBS was admitted for possible catheter-related sepsis. She was asplenic and had insulin-dependent diabetes mellitus as a result of a pancreatic resection. A large skin ulceration was present on her left calf, which appeared unusual for a disseminated bacterial infection. Chest x-ray and computed tomography scan revealed multiple subpleural pulmonary infiltrates consistent with bacterial or fungal dissemination. Blood cultures from the port system and from the peripheral blood grew Staphylococcus haemolyticus and Fusarium oxysporum. The port system was removed, and flucloxacillin and voriconazole were given for 33 and 35 days, respectively. Clinical signs of disseminated sepsis resolved slowly. Bone marrow biopsy ruled out primary hematologic disease.

CONCLUSIONS

(1) Catheter-related sepsis in patients on HPN is usually caused by Gram-positive or Gram-negative bacteria or by Candida species. Identification of molds in blood cultures strongly suggests Fusarium species, which should be treated appropriately with voriconazole or amphotericin B. (2) HPN and SBS aggravated by asplenism and diabetes mellitus can cause severe immunocompromise. (3) Fusaria have a strong tendency to persist or reappear after bone marrow transplantation, which is therefore relatively contraindicated in these patients.

An evaluation of the model for end-stage liver disease and serum C-reactive protein as prognostic markers in intestinal failure patients on parenteral nutrition

BACKGROUND

Intestinal failure (IF) patients require parenteral nutrition (PN) to avoid malnutrition and death. However, they face complications of recurrent sepsis and liver failure. By the time liver failure is discovered, it is often too late for intervention and prognosis on the waiting list is grim. The Model for End-Stage Liver Disease (MELD) has traditionally been used to predict mortality in patients with liver failure but has never been analyzed in IF patients who are at risk for liver complications. C-reactive protein (CRP) is an acute inflammatory marker that has been shown to reflect disease progression in nonalcoholic steatohepatitis, a disease that in many ways resembles PN-associated liver disease. MELD and CRP are promising clinical markers of disease progression in IF patients on PN.

METHODS

The authors performed a retrospective, case-control study to compare levels of MELD and CRP within the entire population of 133 adult patients referred to Northwestern Memorial Hospital for IF from 1999 to 2006.

RESULTS

Elevated MELD score is strongly predictive of increased mortality over the subsequent 6 months. Elevated CRP is strongly predictive over a smaller 3-month window. One-year mortality was significantly greater in patients who have either elevated MELD scores or serum CRP levels.

CONCLUSIONS

In this study, the authors evaluated for the first time use of MELD and serum CRP as predictive markers of mortality in IF patients. Both seem to be promising clinical tools to identify which patients are at highest risk for complication.

Detectable serum flagellin and lipopolysaccharide and upregulated anti-flagellin and lipopolysaccharide immunoglobulins in human short bowel syndrome

Gut barrier dysfunction may occur in short bowel syndrome (SBS). We hypothesized that systemic exposure to flagellin and lipopolysaccharide (LPS) in SBS might regulate specific immune responses. We analyzed serial serum samples obtained from parenteral nutrition (PN)-dependent patients with SBS versus non-SBS control serum. Serum from 23 adult SBS patients was obtained at baseline and 4, 8, 12, 16, 20, and 24 wk in a trial of modified diet with or without growth hormone. Control serum was obtained from 48 healthy adults and 37 adults requiring PN during critical illness. Serum flagellin was detected by an ELISA recognizing an array of gram-negative flagellins, and LPS was detected by limulus assay. Serum flagellin- and LPS-specific immunoglobulin levels (IgM, IgA, and IgG) were determined by ELISA. Serum flagellin and LPS were undetectable in control subjects. In contrast, serum flagellin, LPS, or both were detected in 14 SBS patients (61%) during one or more time points [flagellin alone, 5/23 (22%); LPS alone, 6/23 (26%); or flagellin + LPS, 3/23 (13%)]. Flagellin-specific serum IgM, IgA, and IgG levels were markedly increased in SBS patients compared with both control populations and remained elevated during the 6-mo study period. LPS-specific IgA was significantly higher in SBS patients compared with healthy controls; LPS-specific IgM, IgA, and IgG levels each decreased over time in association with PN weaning. We conclude that adults with PN-dependent SBS are systemically exposed to flagellin and LPS, presumably from the gut lumen. This likely regulates innate and adaptive immune responses to these specific bacterial products.

Metabolic bone disease in gastrointestinal illness

Metabolic bone disease is often silent, often undiagnosed, and occurs frequently in patients with chronic gastrointestinal illnesses. Potentially modifiable risk factors, such as malnutrition, malabsorption, prolonged use of glucocorticoids, and a sedentary lifestyle, can lead to low bone mass, an increased rate of bone loss, and debilitating bone disease. This article explores common gastrointestinal illnesses that place patients at risk for developing metabolic bone disease. Concepts are presented to assist the practitioner in identifying patients at risk; clinical evaluation and diagnostic test selection are discussed, and therapeutic options for the prevention and treatment of metabolic bone disease in gastrointestinal illness are presented.

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.