Noninvasive Fecal Cytokine and Microbiota Profiles Predict Commencement of Necrotizing Enterocolitis in a Proof-of-Concept Study

Background and Aims

Necrotizing enterocolitis (NEC) is a life-threatening disease and the most common gastrointestinal emergency in premature infants. Accurate early diagnosis is challenging. Modified Bell's staging is routinely used to guide diagnosis, but early diagnostic signs are nonspecific, potentially leading to unobserved disease progression, which is problematic given the often rapid deterioration observed. We investigated fecal cytokine levels, coupled with gut microbiota profiles, as a noninvasive method to discover specific NEC-associated signatures that can be applied as potential diagnostic markers.

Methods

Premature babies born below 32 weeks of gestation were admitted to the 2-site neonatal intensive care unit (NICU) of Imperial College hospitals (St. Mary's or Queen Charlotte's & Chelsea) between January 2011 and December 2012. During the NICU stay, expert neonatologists grouped individuals by modified Bell's staging (healthy, NEC1, NEC2/3) and fecal samples from diapers were collected consecutively. Microbiota profiles were assessed by 16S rRNA gene amplicon sequencing and cytokine concentrations were measured by V-Plex multiplex assays.

Results

Early evaluation of microbiota profiles revealed only minor differences. However, at later time points, significant changes in microbiota composition were observed for Bacillota (adj. P = .0396), with Enterococcus being the least abundant in Bell stage 2/3 NEC. Evaluation of fecal cytokine levels revealed significantly higher concentrations of IL-1α (P = .045), IL-5 (P = .0074), and IL-10 (P = .032) in Bell stage 1 NEC compared to healthy individuals.

Conclusion

Differences in certain fecal cytokine profiles in patients with NEC indicate their potential use as diagnostic biomarkers to facilitate earlier diagnosis. Additionally, associations between microbial and cytokine profiles contribute to improving knowledge about NEC pathogenesis.

Recent advances in understanding and managing pediatric nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of disease that can range from isolated macrovesicular hepatocellular steatosis to nonalcoholic steatohepatitis (NASH) with or without fibrosis to cirrhosis. The prevalence of NAFLD has increased over several decades, mirroring the global obesity pandemic. NAFLD currently represents the most common etiology of chronic liver disease in children and adolescents worldwide. Disease presentation in childhood strongly suggests that these children may have unique susceptibilities and more severe long-term consequences. Emerging data demonstrate that the pathogenesis of early-onset NAFLD is secondary to a complex interplay involving genetic, metabolic, environmental, and microbiological factors. Such influences may begin in utero. Dietary and lifestyle modifications remain the primary effective therapeutic interventions, although long-term efficacy is limited by poor adoption or adherence. Advances in the development and validation of non-invasive biomarkers and imaging modalities will facilitate diagnosis for affected children and adolescents and facilitate long-term natural history studies and the development of therapeutic interventions.

Mechanisms of Fibrosis Development in Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease is the most prevalent liver disease worldwide, affecting 20%-25% of the adult population. In 25% of patients, nonalcoholic fatty liver disease progresses to nonalcoholic steatohepatitis (NASH), which increases the risk for the development of cirrhosis, liver failure, and hepatocellular carcinoma. In patients with NASH, liver fibrosis is the main determinant of mortality. Here, we review how interactions between different liver cells culminate in fibrosis development in NASH, focusing on triggers and consequences of hepatocyte-macrophage-hepatic stellate cell (HSC) crosstalk. We discuss pathways through which stressed and dead hepatocytes instigate the profibrogenic crosstalk with HSC and macrophages, including the reactivation of developmental pathways such as TAZ, Notch, and hedgehog; how clearance of dead cells in NASH via efferocytosis may affect inflammation and fibrogenesis; and insights into HSC and macrophage heterogeneity revealed by single-cell RNA sequencing. Finally, we summarize options to therapeutically interrupt this profibrogenic hepatocyte-macrophage-HSC network in NASH.

Clinically Significant Fibrosis Is Associated With Longitudinal Increases in Fibrosis-4 and Nonalcoholic Fatty Liver Disease Fibrosis Scores

BACKGROUND & AIMS

There is limited knowledge regarding the longitudinal utility of biomarkers of fibrosis, such as the nonalcoholic fatty liver disease (NAFLD) fibrosis score (NFS) or the fibrosis-4 score (FIB-4) score. We examined longitudinal changes in the NFS and the FIB-4 score in patients with NAFLD, with and without clinically significant fibrosis (CSF).

METHODS

We performed a retrospective study of 230 patients with NAFLD, collecting clinical and laboratory records to calculate NFS and FIB-4 scores at 6 monthly intervals for 5 years before hepatology assessment of fibrosis. Linear mixed models with random intercept and slope and adjusted for age at baseline were used to assess the progression of NFS and log-transformed FIB-4 scores over time in subjects with and without CSF, determined by liver stiffness measurements of 8.2 kPa or greater.

RESULTS

Patients had a median of 11 (minimum, 10; maximum, 11) retrospective observations over a median time period of 5 years (minimum, 4.5 y; maximum, 5 y). Of patients with low baseline NFS and FIB-4 scores, 31.11% and 37.76%, respectively, had CSF at the time of hepatology assessment. There was a correlation between NFS and log₁₀ FIB-4 over time (repeated measure r = 0.55; 95% CI, 0.52-0.59). The rate of increase in NFS and log₁₀ FIB-4 was significantly higher in patients with than without CSF (both P < .001). Predicted NFS increased by 0.17 and 0.06 units per year in subjects with and without CSF, respectively. Predicted log₁₀ FIB-4 score increased by 0.032 and 0.0003 units per year in subjects with and without CSF, respectively.

CONCLUSIONS

Noninvasively measured fibrosis scores increase progressively in patients with NAFLD and CSF. Further studies are needed to determine whether repeated measurements can identify patients at risk for CSF.