Low serum citrulline concentration correlates with catheter-related bloodstream infections in children with intestinal failure

Current short bowel syndrome management: An era of improved outcomes and continued challenges

Prior to the late 1960s, pediatric short bowel syndrome was a frequently fatal disease. Currently, pediatric interdisciplinary bowel rehabilitation centers report very high survival rates. The mortality trends, up-to-date definitions, incidence, causes, and clinical manifestations of short bowel syndrome are reviewed. Emphasis is placed upon the nutritional, medical, and surgical advances that have contributed to the dramatic improvement in outcomes for pediatric short bowel syndrome patients. Recent findings and remaining challenges are highlighted.

Free amino acid composition of saliva in patients with healthy periodontium and periodontitis

OBJECTIVES

To identify and compare the free amino acids in the saliva of periodontitis patients and healthy individuals and to assess their levels in different periodontal disease types.

MATERIALS AND METHODS

There were three groups: healthy individuals (control (C); n = 20), Stage III Grade B generalized periodontitis (GP-B; n = 20), and Stage III Grade C generalized periodontitis (GP-C; n = 20). Clinical periodontal parameters were measured. Amino acid analysis of the saliva was accomplished by liquid chromatography-mass spectrometry (LC MS/MS), taking the mean concentration.

RESULTS

Citrulline and carnosine concentrations were significantly higher in patients with periodontitis than in the control group (p < 0.017). Methionine, glutamic acid, and arginine showed significantly higher concentrations in GP-C, whereas proline and tryptophan showed higher concentrations in the GP-B group (p < 0.017). There was a significant correlation between methionine, citrulline, arginine, and carnosine and clinical periodontal parameters.

CONCLUSIONS

Our results demonstrate that periodontal status and disease type can result in variations in salivary amino acid (AA) content in correlation with clinical inflammatory signs. The significant correlation of methionine, citrulline, carnosine, and arginine with clinical parameters, regardless of systemic status, suggests that the levels of different salivary free AAs play roles in periodontitis.

CLINICAL RELEVANCE

Salivary free AAs may be suggested as a potential diagnostic compound in patients with periodontitis.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT04642716.

Biomarkers of sepsis: time for a reappraisal

INTRODUCTION

Sepsis biomarkers can have important diagnostic, therapeutic, and prognostic functions. In a previous review, we identified 3370 references reporting on 178 different biomarkers related to sepsis. In the present review, we evaluate the progress in the research of sepsis biomarkers.

METHODS

Using the same methodology as in our previous review, we searched the PubMed database from 2009 until September 2019 using the terms "Biomarker" AND "Sepsis." There were no restrictions by age or language, and all studies, clinical and experimental, were included.

RESULTS

We retrieved a total of 5367 new references since our previous review. We identified 258 biomarkers, 80 of which were new compared to our previous list. The majority of biomarkers have been evaluated in fewer than 5 studies, with 81 (31%) being assessed in just a single study. Apart from studies of C-reactive protein (CRP) or procalcitonin (PCT), only 26 biomarkers have been assessed in clinical studies with more than 300 participants. Forty biomarkers have been compared to PCT and/or CRP for their diagnostic value; 9 were shown to have a better diagnostic value for sepsis than either or both of these biomarkers. Forty-four biomarkers have been evaluated for a role in answering a specific clinical question rather than for their general diagnostic or prognostic properties in sepsis.

CONCLUSIONS

The number of biomarkers being identified is still increasing although at a slower rate than in the past. Most of the biomarkers have not been well-studied; in particular, the clinical role of these biomarkers needs to be better evaluated.

Risk Factors of Ambulatory Central Line-Associated Bloodstream Infection in Pediatric Short Bowel Syndrome

BACKGROUND

Children with short bowel syndrome (SBS) receiving home parenteral nutrition (HPN) are predisposed to ambulatory central line-associated bloodstream infection (A-CLABSI). Data describing risk factors of this infection in children are limited.

METHODS

Retrospective cohort, single-center, case-crossover study of children ≤18 years old with SBS receiving HPN from January 2012 to December 2016. Univariate and multivariate mixed effect Poisson regression identified the relative risk (RR) of A-CLABSI with proposed risk factors.

RESULTS

Thirty-five children were identified; median follow-up was 30 months. A-CLABSI rate was 4.2 per 1000 central line (CL) days. Univariate analysis identified younger age (RR: 0.92 per 12-month increase [95% confidence interval {CI}: 0.85-0.99; P = 0.036]), shorter small intestine length (RR: 0.96 per 10-cm increase [95% CI: 0.92-0.99; P = 0.008]), lower citrulline level (RR: 0.86 per 5-nmol/mL increase [95% CI: 0.75-0.99; P = 0.036]), and recent CL break (RR: 1.55 [95% CI: 1.06-2.28; P = 0.024]) as risk factors for A-CLABSI. Multivariate analysis showed increased A-CLABSI with clinical diagnosis of small intestine bacterial overgrowth (SIBO) (RR: 1.87 [95% CI: 1.1-3.17; P = 0.021]) and CL breaks (RR: 1.49 [95% CI: 1-2.22; P = 0.024]).

CONCLUSIONS

Factors influencing gut integrity increase A-CLABSI rate, supporting translocation as an important mechanism and target for prevention. Clinical diagnosis of SIBO increases A-CLABSI rate, but whether dysbiosis or diarrhea is responsible is an area for future research. CL maintenance is crucial, and prevention of breaks would likely decrease A-CLABSI rate.

Nutritional therapy complications in children with ultra-short bowel syndrome include growth deficiency but not cholestasis

Aim

Children with ultra‐short bowel syndrome (USBS) have not been extensively studied to date because the condition is rare. The aim of the study was to assess the nutritional status of children with USBS receiving home parenteral nutrition, using citrulline serum concentration and cholestasis.

Methods

We studied 17 patients with USBS, with a median age of 6.6 years and median duration of parenteral nutrition of 6.6 years. The study was carried out at The Children's Memorial Health Institute, Warsaw, from January 2014 to January 2015.

Results

The median standard deviation score (SDS) was −1.2 for body mass according to chronological age, −1.72 according to height and −0.59 according to height for age. Patients requiring seven days per week parenteral nutrition had a citrulline concentration below 10 μmol/L. Decreased bone‐mineral density was observed in 87% of the patients. Low values of 25‐hydroxyvitamin D were found in 53% of the children. None of the patients had elevated conjugated bilirubin levels above 34.2 μmol/L.

Conclusion

Children with USBS were growth deficient according to their chronological age, with frequent abnormal bone mineralisation and vitamin D deficiency. Children requiring parenteral nutrition seven days a week had citrulline concentrations below 10 μmol/L. Cholestasis was not seen.

Markers of Environmental Enteric Dysfunction Are Associated With Neurodevelopmental Outcomes in Tanzanian Children

BACKGROUND

Chronic exposure to enteropathogens may result in environmental enteric dysfunction (EED), a subclinical condition associated with poor child growth. Growth faltering is strongly associated with poor neurodevelopment, and occurs during sensitive periods of postnatal brain development. We investigated the role of novel EED biomarkers, systemic inflammation, and micronutrient status on neurodevelopment in Tanzanian children.

METHODS

Non-stunted subjects with 6-week and 6-month blood samples and neurodevelopmental measures (n = 107) were included in this study. Samples were tested for biomarkers of gastrointestinal function (citrulline, antibodies to lipopolysaccharide, and flagellin), micronutrient status (iron, retinol binding protein [RBP], and vitamin D), systemic inflammation (C-reactive protein [CRP] and alpha-1-acid glycoprotein), and growth (insulin-like growth factor and insulin-like growth factor binding protein 3).

RESULTS

Cognitive scores at 15 months were associated with higher concentrations of 6-month anti-lipopolysaccharide IgG (β = 1.95, P = 0.02), anti-flagellin IgA (β = 2.41, P = 0.04), and IgG (β = 2.99, P = 0.009). Higher receptive language scores were positively associated with anti-flagellin IgG (β = 0.95, P = 0.05), and receptive language and gross motor scores were positively associated with citrulline at 6 months (β = 0.09, P = 0.02; β = 0.10, P = 0.03, respectively). Gross motor scores were positively associated with RBP at 6 months (β = 1.70, P = 0.03). Markers of systemic inflammation were not significantly associated with neurodevelopment.

CONCLUSIONS

Plasma citrulline, a marker of gastrointestinal mucosal surface area, and vitamin A status were associated with higher gross motor development scores. Novel markers for EED, but not inflammation, were positively associated with cognitive scores, suggesting a possible mechanistic pathway involving immune response and neuroprotection.

Necrotizing enterocolitis is associated with earlier achievement of enteral autonomy in children with short bowel syndrome

PURPOSE

Necrotizing enterocolitis (NEC) remains one of the most common underlying diagnoses of short bowel syndrome (SBS) in children. The relationship between the etiology of SBS and ultimate enteral autonomy has not been well studied. This investigation sought to evaluate the rate of achievement of enteral autonomy in SBS patients with and without NEC.

METHODS

Following IRB approval, 109 patients (2002-2014) at a multidisciplinary intestinal rehabilitation program were reviewed. The primary outcome evaluated was achievement of enteral autonomy (i.e. fully weaning from parenteral nutrition). Patient demographics, primary diagnosis, residual small bowel length, percent expected small bowel length, median serum citrulline level, number of abdominal operations, status of the ileocecal valve (ICV), presence of ileostomy, liver function tests, and treatment for bacterial overgrowth were recorded for each patient.

RESULTS

Median age at PN onset was 0 weeks [IQR 0-0]. Median residual small bowel length was 33.5 cm [IQR 20-70]. NEC was present in 37 of 109 (33.9%) of patients. 45 patients (41%) achieved enteral autonomy after a median PN duration of 15.3 [IQR 7.2-38.4]months. Overall, 64.9% of patients with NEC achieved enteral autonomy compared to 29.2% of patients with a different primary diagnosis (p=0.001, Fig. 1). Patients with NEC remained more likely than those without NEC to achieve enteral autonomy after two (45.5% vs. 12.0%) and four (35.7% vs. 6.3%) years on PN (Fig. 1). Logistic regression analysis demonstrated the following parameters as independent predictors of enteral autonomy: diagnosis of NEC (p<0.002), median serum citrulline level (p<0.02), absence of a jejunostomy or ileostomy (p=0.013), and percent expected small bowel length (p=0.005).

CONCLUSIONS

Children with SBS because of NEC have a significantly higher likelihood of fully weaning from parenteral nutrition compared to children with other causes of SBS. Additionally, patients with NEC may attain enteral autonomy even after long durations of parenteral support.

Catheter-related blood stream infection caused by Dermacoccus barathri, representing the first case of Dermacoccus infection in humans

A 7-year-old boy undergoing home parenteral nutrition with totally implantable central venous access device for chronic intestinal pseudo-obstruction experienced repeated episodes of fever with a temperature above 39.0 °C despite the antibiotic treatment. The fever was considered to be catheter-related blood stream infections, as no other etiology could be justified. Repeated blood culture tests revealed negative after 1-week incubation, whereas some samples of blood collected from the central venous catheter yielded positive and gram-positive rods were detected. These bacteria were detected repeatedly, then the central venous access device was removed with consideration for the possibility of this bacteria being a pathogen. Thereafter, the fever did not recur and the blood culture tests were negative. The causative agent was identified as Dermacoccus barathri based on the 16S rRNA gene sequence and phylogenetic analysis of 6118-bp concatenated sequences of 4 housekeeping genes. Genus Dermacoccus are one form of Actinomycetes isolated from human skin and water, but human infection with Dermacoccus spp. has not been previously reported and the pathogenicity of the bacteria remains unclear. To our knowledge, this is the first reported case of Dermacoccus infection in humans.

Central line-associated bloodstream infections in neonates with gastrointestinal conditions: developing a candidate definition for mucosal barrier injury bloodstream infections

OBJECTIVE

To develop a candidate definition for central line-associated bloodstream infection (CLABSI) in neonates with presumed mucosal barrier injury due to gastrointestinal (MBI-GI) conditions and to evaluate epidemiology and microbiology of MBI-GI CLABSI in infants.

DESIGN

Multicenter retrospective cohort study.

SETTING

Neonatal intensive care units from 14 US children's hospitals and pediatric facilities.

METHODS

A multidisciplinary focus group developed a candidate MBI-GI CLABSI definition based on presence of an MBI-GI condition, parenteral nutrition (PN) exposure, and an eligible enteric organism. CLABSI surveillance data from participating hospitals were supplemented by chart review to identify MBI-GI conditions and PN exposure.

RESULTS

During 2009-2012, 410 CLABSIs occurred in 376 infants. MBI-GI conditions and PN exposure occurred in 149 (40%) and 324 (86%) of these 376 neonates, respectively. The distribution of pathogens was similar among neonates with versus without MBI-GI conditions and PN exposure. Fifty-nine (16%) of the 376 initial CLABSI episodes met the candidate MBI-GI CLABSI definition. Subsequent versus initial CLABSIs were more likely to be caused by an enteric organism (22 of 34 [65%] vs 151 of 376 [40%]; P = .009) and to meet the candidate MBI-GI CLABSI definition (19 of 34 [56%] vs 59 of 376 [16%]; P < .01).

CONCLUSIONS

While MBI-GI conditions and PN exposure were common, only 16% of initial CLABSIs met the candidate definition of MBI-GI CLABSI. The high proportion of MBI-GI CLABSIs among subsequent infections suggests that infants with MBI-GI CLABSI should be a population targeted for further surveillance and interventional research.

Serum citrulline as a biomarker of gastrointestinal function during hematopoietic cell transplantation in children

OBJECTIVES

We sought to determine whether serum citrulline (CIT), an amino acid produced by small bowel enterocytes, was associated with clinical and biochemical markers of gastrointestinal function in children undergoing hematopoietic cell transplantation (HCT).

METHODS

We conducted a multicenter, prospective cohort study of 26 children to define time-related changes in serum CIT during the course of HCT. Markers of gastrointestinal function including oral energy intake, emesis, stool volume, presence of graft-versus-host disease (GVHD), oral mucositis severity, and cytokine and neurohormone levels were measured. Weekly serum CIT concentrations were obtained from 10 days prior until 30 days after HCT.

RESULTS

Mean baseline CIT concentration was 22.7 μmol/L (95% confidence interval [CI] 17.7-27.6) on day -10, which decreased to a nadir of 7.5 μmol/L (95% CI 3.1-18.0, P = 0.017) on day 8 following HCT before returning to baseline by day 30. After adjustment for IL-6 level (1.0% lower CIT per 10% increase in interleukin-6, P = 0.004), presence of acute GVHD (27% lower CIT, P = 0.025), and oral energy intake (2.1% lower CIT per 10% decrease in energy intake, P = 0.018), the nadir shifted to day 10, when mean CIT concentration was lower in patients with severe oral mucositis (6.7 μmol/L, 95% CI 3.4-13.1) than in those without severe mucositis (11.9 μmol/L, 95% CI 5.8-24.4, P = 0.003). Change in CIT was not correlated with stool volume, C-reactive protein, tumor necrosis factor-α, leptin, or ghrelin.

CONCLUSIONS

In children undergoing HCT, serum CIT correlates with measures of gastrointestinal function (oral mucositis severity, dietary intake, acute GVHD) and may reflect mucosal injury to the gastrointestinal tract.

Citrulline levels following proximal versus distal small bowel resection

PURPOSE

Citrulline, a nonprotein amino acid synthesized by enterocytes, is a biomarker of bowel length and the capacity to wean from parenteral nutrition. However, the potentially variant effect of jejunal versus ileal excision on plasma citrulline concentration [CIT] has not been studied. This investigation compared serial serum [CIT] and mucosal adaptive potential after proximal versus distal small bowel resection.

METHODS

Enterally fed Sprague-Dawley rats underwent sham operation or 50% small bowel resection, either proximal (PR) or distal (DR). [CIT] was measured at operation and weekly for 8 weeks. At necropsy, histologic features reflecting bowel adaptation were evaluated.

RESULTS

By weeks 6-7, [CIT] in both resection groups significantly decreased from baseline (P<0.05) and was significantly lower than the concentration in sham animals (P<0.05). There was no difference in [CIT] between PR and DR at any point. Villus height and crypt density were higher in the PR than in the DR group (P≤0.02).

CONCLUSION

[CIT] effectively differentiates animals undergoing major bowel resection from those with preserved intestinal length. The region of intestinal resection was not a determinant of [CIT]. The remaining bowel in the PR group demonstrated greater adaptive potential histologically. [CIT] is a robust biomarker for intestinal length, irrespective of location of small intestine lost.

Reduced plasma citrulline levels in low birth weight infants with necrotizing enterocolitis

BACKGROUND

Citrulline, a nonprotein amino acid, is an intermediate of the urea cycle and synthesized in small intestine. Lower plasma citrulline levels were associated with reduced function of enterocytes. Necrotizing enterocolitis (NEC) causes high morbidity and mortality, and leads impaired intestinal functions.

METHODS

Plasma citrulline levels of neonates with a gestational age <32 weeks and ≤1,500 gm who developed NEC stage II/III were measured by high-performance liquid chromatography.

RESULTS

We enrolled 36 preterm infants including 20 with NEC and 16 controls. Median citrulline levels of NEC and control groups were 8.6 and 20.18 μmol/l (P < 0.05), and cut off level of citrulline was 13.15 μmol/l with a sensitivity of 80% and a specificity of 82%. Median arginine levels of NEC and control groups were 22.02 and 39.89 μmol/l (P < 0.05), and cut off level of arginine was 28.52 μmol/l with a sensitivity of 70% and a specificity of 75%. Blood sampling day, gender, parenteral, and enteral nutrition did not affect the amino acid levels.

CONCLUSION

We found lower plasma citrulline and arginine levels in preterm infants with NEC. Further studies are needed to determine most appropriate levels to predict recovery and prognosis of NEC, and treatment options with these amino acids in preterm infants.

Management of short bowel syndrome

Most intestinal failure in children is due to short bowel syndrome (SBS) where congenital or acquired lesions have led to an extensive loss of intestinal mass. The vast majority of morbidity and mortality of patients with SBS is due to complications secondary to their long term dependence on parenteral nutrition. In response to SBS, the intestine undergoes a process of remodeling termed adaptation. Principles guiding the medical management of SBS include providing adequate parenteral nutrition, fluids and electrolytes for growth and normal development, promoting small bowel adaptation, and preventing and treating complications related to the patient's underlying disease and their parenteral nutrition. Catheter associated blood stream infection (CABSI) is major source of morbidity and mortality in patients with intestinal failure from SBS. Intestinal failure associated liver disease (IFALD)is another major source of morbidity and mortality in patients with SBS. IFALD is the most consistent negative predictor of outcome including death and continued parenteral nutrition dependence. Enteral nutrition is critical for intestinal adaptation and preventing IFALD. Patients with SBS who develop dilated dysmotile segments may benefit from autologous intestinal reconstruction surgery (AIRS) with the goal of decreasing stasis and disordered motility through intestinal narrowing and lengthening. Patients with SBS should be referred for transplantation if they have failed intestinal rehabilitation including AIRS, have no reasonable chance for enteral feeding tolerance, develop irreversible IFALD, have recurrent sepsis, or have exhausted their central venous access sites. With improvements in medical and surgical care, overall survival of patients with SBS now exceeds 90%.

Medical update and potential advances in the treatment of pediatric intestinal failure

Short bowel syndrome (SBS) and intestinal failure are chronic malabsorption disorders with considerable nutritional and growth consequences in children. Intestinal failure occurs when the functional gastrointestinal mass is reduced even if there is normal anatomical gastrointestinal length. A number of management strategies are often utilized to achieve successful intestinal rehabilitation and maintain adequate nutrition to avoid intestinal transplant. These strategies include minimizing the effect of parenteral associated liver disease, limiting catheter complications, and treating bacterial overgrowth in the remaining small intestine. In addition, there continues to be significant research interest in enhancing intestinal adaptation with targeted therapies. The purpose of this review is to discuss current perspectives and to highlight recent medical advances in novel investigational therapies.

Plasma citrulline concentration as a biomarker for bowel loss and adaptation in hospitalized pediatric patients requiring parenteral nutrition

BACKGROUND

Citrulline is a nonessential amino acid produced solely in the enterocyte. Plasma citrulline concentration has been proposed as a noninvasive biomarker for bowel length, function, and dependency on parenteral nutrition (PN). The purpose of this study was to determine if citrulline concentrations differed between pediatric patients with and without small bowel loss requiring specialized nutrition support.

METHODS

This was a retrospective categorical analysis of citrulline concentrations from previously published studies. Patients were included if they were receiving PN, more than 30 days of age, and if they had at least 2 plasma citrulline concentrations. Patients with renal insufficiency and who received outpatient PN treatment were excluded. Patients were categorized as either having or not having small bowel loss.

RESULTS

Thirty-six patients were included for analysis (18 per category). The median citrulline concentration was significantly lower in the group with bowel loss, 8.4 µmol/L vs 10.5 µmol/L (P < .0005), and undetectable citrulline concentrations occurred more often in the bowel loss group, 40% vs 8% (P < .0005). In 13 patients who received enteral nutrition during the study periods, plasma citrulline concentrations increased only in patients without bowel loss.

CONCLUSIONS

These data confirm previous studies and identify decreased citrulline concentrations in pediatric patients with bowel dysfunction in the absence of bowel loss. These data also represent the first serial citrulline concentrations over a 21-day period. The increase in citrulline concentrations only in fed patients without bowel loss suggests that citrulline concentrations could provide a biomarker for bowel function and adaptation.