Clinical significance of FABP2 expression in newborns with necrotizing enterocolitis

Values of serum intestinal fatty acid-binding protein, fecal calprotectin, and fecal human β-defensin 2 for predicting necrotizing enterocolitis

BACKGROUND

This study aimed to assess the diagnostic potential of serum intestinal fatty acid-binding protein (I-FABP), fecal calprotectin (FC), and fecal human β-defensin 2 (hBD2) in predicting necrotizing enterocolitis (NEC) in preterm infants.

METHODS

A prospective cohort of neonates with a gestational age < 32 weeks, suspected of NEC, was enrolled between June 2021 and December 2022. Serum I-FABP, FC, and fecal hBD2 levels were measured upon NEC suspicion, and diagnosis was confirmed through radiological examination or surgical intervention. Diagnostic precision of serum I-FABP, FC, and fecal hBD2 was assessed using a logistic regression model with multiple variables.

RESULTS

The study included 70 neonates (45 males, 25 females), with 30 developing NEC (40% Stage III, n = 12; 60% Stage II, n = 18) and 40 in the control group. NEC patients exhibited significantly higher serum I-FABP and FC levels (4.76 ng/mL and 521.56 µg/g feces, respectively) than those with other diagnoses (1.38 ng/mL and 213.34 µg/g feces, respectively; p ˂ 0.05 for both biomarkers). Stage II NEC neonates showed elevated fecal hBD2 levels (376.44 ng/g feces) than Stage III NEC neonates and controls (336.87 ng/g and 339.86 ng/g feces, respectively; p ˂ 0.05). No such increase was observed in infants progressing to Stage III NEC. Using a serum I-FABP threshold of > 2.54 ng/mL yielded 76.7% sensitivity, 87.5% specificity, 82.1% positive predictive value (PPV), and 83.3% negative predictive value (NPV). For FC (cutoff > 428.99 µg/g feces), corresponding values were 76.7% sensitivity, 67.5% specificity, 63.9% PPV, and 79.4% NPV.

CONCLUSION

Serum I-FABP and FC levels are valuable for early NEC detection and provide insights into disease severity. Low fecal hBD2 levels suggest an inadequate response to luminal bacteria, potentially rendering these infants more susceptible to NEC development or exacerbation.

Integrated Transcriptome and 16S rDNA Analyses Reveal That Transport Stress Induces Oxidative Stress and Immune and Metabolic Disorders in the Intestine of Hybrid Yellow Catfish (Tachysurus fulvidraco♀ × Pseudobagrus vachellii♂)

Live fish are often transported in aquaculture. To explore the effects of transport stress, hybrid yellow catfish (Tachysurus fulvidraco♀ × Pseudobagrus vachellii♂) were subjected to simulated transport treatments (0–16 h) with 96 h of recovery after the 16-h transport treatment, and intestinal biochemical parameters, the transcriptome, and gut microbiota were analyzed. Transportation affected the number of mucus cells and led to oxidative stress in the intestine, which activated immune responses. Changes in lipid metabolism reflected metabolic adaptation to oxidative stress. Toll-like receptor signaling, peroxisome proliferator-activated receptor signaling, and steroid biosynthesis pathways were involved in the transport stress response. Gene expression analyses indicated that transport-induced local immune damage was reversible, whereas disordered metabolism recovered more slowly. A 16S rDNA analysis revealed that transport stress decreased the alpha diversity of the gut microbiota and disrupted its homeostasis. The dominant phyla (Fusobacteria, Bacteroidetes) and genera (Cetobacterium, Barnesiellaceae) were involved in the antioxidant, immune, and metabolic responses of the host to transportation stress. Correlation analyses suggested that gut microbes participate in the transport stress response and the host–microbiota interaction may trigger multiple events in antioxidant, immune, and metabolic pathways. Our results will be useful for optimizing transport processes.

Association between glial fibrillary acidic protein, glial-derived neurotrophic factor, and fatty acid-binding protein-2 at birth in the incidence of necrotizing enterocolitis in preterm infants

BACKGROUND

This study aimed to analyze the relationship between glial fibrillary acidic protein (GFAP), glial-derived neurotrophic factor (GDNF), and fatty acid-binding protein-2 (FABP-2) in preterm infants on the incidence of NEC.

METHODS

Preterm infants with a birth weight <1,500 g and gestational age <34 weeks were included in this study. Biomarker examination was performed using the umbilical vein blood at birth (first sample). Biomarker examination was repeated if the infant developed symptoms of NEC using peripheral vein blood (second sample). Infants were observed for 14 days. If NEC did not exist, a biomarker examination was performed at 14 days.

RESULTS

This study included 30 preterm infants, nine infants experienced NEC. The values of GFAP, GDNF, and FABP-2 (median and range) in the group with NEC were higher than those in the group without NEC in both the first samples {GFAP [1.40 (0.20-6.50) vs. 0.30 (0.10-1.30) P = 0.014], GDNF [2.84 (1.05-14.11) vs. 1.56 (1.07-3.48) P = 0.050], and FABP-2 [621.70 (278.40-2,207.00) vs. 294.20 (211.40-597.50) P = 0.002]} and second samples {GFAP [2.40 (0.30-3.10) vs. 0.30 (0.10-0.60) P = 0.003], GDNF [2.99 (0.56-10.30) vs. 1.46 (0.85-2.24) P = 0.019], and FABP-2 [646.8 (179.20-1,571.00) vs. 314.90 (184.70-521.60) P = 0.040]}. In infants with NEC, the median values of GFAP [2.40 (0.30-3.10) vs. 1.40 (0.20-6.50) P = 0.767], GDNF [2.99 (0.56-10.30) vs. 2.84 (1.05-14.11) P = 0.859], and FABP-2 [646.80 (179.20-1,571.00) vs. 621.70 (278.40-2,207.00) P = 0.953] in the second sample were higher than those in the first sample. Logistic regression demonstrated that GFAP at birth (Odds Ratio [OR] = 15.629, 95% Confidence Interval [CI] = 1.697-143.906, P = 0.015) and FABP-2 levels at birth (OR = 1.008, 95% CI = 1.001-1.015, P = 0.033) were significantly associated with an increased risk of NEC.

CONCLUSION

Increased GFAP, GDNF, and FABP-2 at birth are associated with NEC occurrence within two weeks of birth. These findings suggest that early-onset NEC is associated with intestinal injury that occurs during the perinatal or even prenatal period.

Potential Role of Serum Intestinal Fatty Acid-Binding Protein as a Marker for Early Prediction and Diagnosis of Necrotizing Enterocolitis in Preterm Neonates

Introduction:

Intestinal fatty acid-binding protein (I-FABP) is located in the apex of mature enterocytes and released into circulation; once the injury of enterocyte happens, its circulating levels are considered an early and sensitive marker of intestinal ischemia as in necrotizing enterocolitis (NEC); because of its small molecular weight, it can be detected in urine.

Aims:

The aim was to study the usefulness of both serum and urine I-FABP in early diagnosis of NEC and to correlate the serum and urinary levels.

Settings and Design:

This study was case–control design.

Methods:

Simultaneous serum and urine samples obtained at the onset of symptoms, in 40 preterms with suspected NEC, with gestational age ± 27.70 weeks and birth weight ± 1.11 kg, i.e., 20 preterms diagnosed at Stage I, 12 preterms at Stage II, and 8 preterms at Stage III, were compared with age- and weight-matched preterms with no NEC.

Statistical Analysis:

The collected data were tabulated, coded, and then analyzed using the computer program Statistical Package for the Social Science (SPSS version 22).

Results:

Serum levels of I-FABP in NEC cases were significantly higher than the control group, with a mean of 6005.77 ± 6384.77 and 1480.79 ± 1276.48 pg/ml, respectively (P < 0.001). Urine levels of I-FABP in NEC cases were significantly higher than the control group, with a mean of 5009.22 ± 3941.64 and 2677.62 ± 2257.29 pg/ml, respectively (P = 0.04). Both serum and urine I-FABP levels not only in Stage II are significantly higher than Stage I but also in Stage III are significantly higher than Stage I and II (P < 0.001, P = 0.03, respectively), which showed significant positive correlation with stages of NEC (r = 0.618; P < 0.001; r = 0.306; P = 0.049, respectively). Both serum and urine I-FABP levels had a highly significant positive correlation with each other (r = 0.406 P < 0.0001). Receiving operating characteristic curve showed an area under the curve of 0.92 and 0.81 for serum and urine I-FABP, respectively.

Conclusions:

Whether serum or urinary I-FABP is valuable in the diagnosis and prediction of NEC and strongly correlated with the disease severity and with each other.

The Role of Gastrointestinal-Related Fatty Acid-Binding Proteins as Biomarkers in Gastrointestinal Diseases

The fatty acid-binding proteins play a major role in intracellular transportation of long-chain fatty acids. Nine fatty acid-binding proteins have been identified, with each having individual tissue-specific functions in addition to regulation of fatty acids. This review focuses on the three fatty acid-binding proteins found in the gastrointestinal tract and discusses their role as diagnostic or disease monitoring markers in neonatal necrotizing enterocolitis, acute mesenteric ischemia, celiac disease, and inflammatory bowel disease. Of these three fatty acid-binding proteins, intestinal fatty acid-binding protein is of the most interest due to its exclusive expression in the gastrointestinal tract. The elevation of intestinal fatty acid-binding protein in blood and urine reflects enterocyte damage, regardless of the underlying cause. The short half-life of intestinal fatty acid-binding protein also means it is a relatively sensitive marker. In contrast, there is currently less evidence to support liver fatty acid-binding protein and ileal bile acid-binding protein as sensitive biomarkers in these conditions. More extensive studies with specific endpoints are required to validate the roles of these fatty acid-binding proteins in gastrointestinal diseases.