Gas chromatography-mass spectrometry based serum metabolic analysis for premature infants and the relationship with necrotizing enterocolitis: a cross-sectional study

Probiotic, Postbiotic, and Paraprobiotic Effects of Lactobacillus rhamnosus as a Modulator of Obesity-Associated Factors

Obesity is a pandemic currently affecting the world's population that decreases the quality of life and promotes the development of chronic non-communicable diseases. Lactobacillus rhamnosus is recognized for multiple positive effects on obesity and overall health. In fact, such effects may occur even when the microorganisms do not remain alive (paraprobiotic effects). This raises the need to elucidate the mechanisms by which obesity-associated factors can be modulated. This narrative review explores recent findings on the effects of L. rhamnosus, particularly, its postbiotic and paraprobiotic effects, on the modulation of adiposity, weight gain, oxidative stress, inflammation, adipokines, satiety, and maintenance of intestinal integrity, with the aim of providing a better understanding of its mechanisms of action in order to contribute to streamlining its clinical and therapeutic applications. The literature shows that L. rhamnosus can modulate obesity-associated factors when analyzed in vitro and in vivo. Moreover, its postbiotic and paraprobiotic effects may be comparable to the more studied probiotic actions. Some mechanisms involve regulation of gene expression, intracellular signaling, and enteroendocrine communication, among others. We conclude that the evidence is promising, although there are still multiple knowledge gaps that require further study in order to fully utilize L. rhamnosus to improve human health.

Mathematical modeling and comparative metabolomics analyses of interactions between Lactiplantibacillus plantarum and Morganella morganii

Morganella morganii is a spoilage microorganism in fish products that produces harmful biogenic amines (BAs). It has been discovered that Lactiplantibacillus plantarum His6 can inhibit the growth of this bacterium. The aim of this study was to quantitatively assess the inhibitory impact of the bioprotective culture Lpb. plantarum His6 on M. morganii YC16 in the matrix (fish and rice) using predictive microbiology models, and elucidate the interaction mechanism through untargeted metabolomics. The mathematical model results showed the inhibition effect of Lpb. plantarum His6 on M. morganii YC16 was dependent on temperature and inoculation concentration. In addition, the simultaneous growth of Lpb. plantarum His6 and M. morganii YC16 could be well simulated with the Lotka-Volterra model. Furthermore, significant decreased in histamine levels was observed in co-(1:3) at 25 °C. Finally, based on the metabolomics data, it was speculated that Lpb. plantarum His6 may enhance bacteriocin production while reducing the yield of glycerophospholipids and fatty acids associated with outer membrane formation, thereby inhibiting the growth of M. morganii YC16. These findings provide valuable insights into the interaction behavior and mechanism of Lpb. plantarum His6 and M. morganii YC16 in co-culture, facilitating the design of the biopreservation strategies for fish products.

High-Resolution and Multidimensional Phenotypes Can Complement Genomics Data to Diagnose Diseases in the Neonatal Population

Advances in genomic medicine have greatly improved our understanding of human diseases. However, phenome is not well understood. High-resolution and multidimensional phenotypes have shed light on the mechanisms underlying neonatal diseases in greater details and have the potential to optimize clinical strategies. In this review, we first highlight the value of analyzing traditional phenotypes using a data science approach in the neonatal population. We then discuss recent research on high-resolution, multidimensional, and structured phenotypes in neonatal critical diseases. Finally, we briefly introduce current technologies available for the analysis of multidimensional data and the value that can be provided by integrating these data into clinical practice. In summary, a time series of multidimensional phenome can improve our understanding of disease mechanisms and diagnostic decision-making, stratify patients, and provide clinicians with optimized strategies for therapeutic intervention; however, the available technologies for collecting multidimensional data and the best platform for connecting multiple modalities should be considered.

Analysis of serum metabolism in premature infants before and after feeding using GC-MS and the relationship with necrotizing enterocolitis

Preterm birth and enteral feeding are two main factors leading to necrotizing enterocolitis (NEC). The metabolomics of preterm infants before and after feeding can provide a basis for the prediction of NEC. Using the method of cross-sectional study, the mode was established with the serum samples of 19 premature infants at birth and after feeding as the control group. The serum was analyzed using GC-MS. Chemometric analysis includes principal component analysis, partial least squares-discriminant analysis, and orthogonal partial least squares-discriminant analysis. Spectral separation of serum metabolites occurred in premature infants before and after feeding. The levels of xylose, d-talose, phosphoglycolic acid, maleimide, l-gulonolactone, maleic acid, β-hydroxypyruvate, itaconic acid, and pantothenic acid in the serum of premature infants after feeding were significant in both multidimensional and single-dimensional modes (variable importance in projection >2, P < 0.01). There was a moderate correlation between total bilirubin and l-gulonolactone and β-hydroxypyruvate (0.8 > r > 0.5). Maleimide, maleic acid, and itaconic acid have diagnostic value (area under the curve >0.9). The results indicated that serum metabolism of preterm infants changes significantly after feeding. Some metabolites have potential value in predicting NEC.

The Metabolome and the Gut Microbiota for the Prediction of Necrotizing Enterocolitis and Spontaneous Intestinal Perforation: A Systematic Review

Necrotizing enterocolitis (NEC) is the most devastating gastrointestinal emergency in preterm neonates. Research on early predictive biomarkers is fundamental. This is a systematic review of studies applying untargeted metabolomics and gut microbiota analysis to evaluate the differences between neonates affected by NEC (Bell’s stage II or III), and/or by spontaneous intestinal perforation (SIP) versus healthy controls. Five studies applying metabolomics (43 cases, 95 preterm controls) and 20 applying gut microbiota analysis (254 cases, 651 preterm controls, 22 term controls) were selected. Metabolomic studies utilized NMR spectroscopy or mass spectrometry. An early urinary alanine/histidine ratio >4 showed good sensitivity and predictive value for NEC in one study. Samples collected in proximity to NEC diagnosis demonstrated variable pathways potentially related to NEC. In studies applying untargeted gut microbiota analysis, the sequencing of the V3−V4 or V3 to V5 regions of the 16S rRNA was the most used technique. At phylum level, NEC specimens were characterized by increased relative abundance of Proteobacteria compared to controls. At genus level, pre-NEC samples were characterized by a lack or decreased abundance of Bifidobacterium. Finally, at the species level Bacteroides dorei, Clostridium perfringens and perfringens-like strains dominated early NEC specimens, whereas Clostridium butyricum, neonatale and Propionibacterium acnei those at disease diagnosis. Six studies found a lower Shannon diversity index in cases than controls. A clear separation of cases from controls emerged based on UniFrac metrics in five out of seven studies. Importantly, no studies compared NEC versus SIP. Untargeted metabolomics and gut microbiota analysis are interrelated strategies to investigate NEC pathophysiology and identify potential biomarkers. Expression of quantitative measurements, data sharing via biorepositories and validation studies are fundamental to guarantee consistent comparison of results.

A Prospective, Case-Control Study of Serum Metabolomics in Neonates with Late-Onset Sepsis and Necrotizing Enterocolitis

Late-onset sepsis (LOS) and necrotizing enterocolitis (NEC) are major causes of neonatal morbidity and mortality. In this prospective, case-control study, we evaluated the metabolic profile of neonates with LOS and NEC. Blood samples were collected from 15 septic neonates and 17 neonates with NEC at the clinical suspicion of the specific diseases. Sixteen gestational and postnatal age-matched neonates without sepsis/NEC served as controls. Serum metabolic profiles were assessed using liquid chromatography–quadrupole time-of-flight mass spectrometry. Metabolomic analysis revealed significant differences in the metabolic profile of neonates with LOS or NEC compared to controls. More specifically, a number of molecules possibly identified as phosphatidylcholines or lysophosphatidylcholines were found to be significantly reduced both in neonates with LOS and those with NEC compared to controls. Additionally, L-carnitine could efficiently discriminate NEC cases from controls. The results of the current study suggest that certain phospholipids and their derivatives could possibly be used as biomarkers for the early detection of LOS and NEC.

Exploring functional metabolites in preterm infants

AIM

Metabolomics is the study of small molecules that represent the functional end points of cellular reactions that can impact health. Necrotising enterocolitis (NEC) and late onset sepsis (LOS) are the main cause of death in preterm infants surviving the initial days of life.

METHODS

This review will explore and summarise the current literature exploring metabolomics in preterm infants.

RESULTS

There are a relatively limited number of studies investigating metabolomics in preterm infants with NEC and/or LOS and matched controls. Nonetheless, it is evident across longitudinally age-related metabolomic studies that there are significant changes in metabolite profiles post-partum and over the first year of life. Existing studies have reported associations between the metabolite profiles of serum, urine and stool in health and disease in preterm infants. Although some studies have found selected metabolites are associated with disease, the specific metabolites vary from study to study, and larger studies are required. Excitingly, recent work has also begun to untangle how microbially produced metabolites can impact immunoregulation of the infant.

CONCLUSION

Metabolic exploration is an emerging research area with huge potential for developing novel biomarkers and better understanding disease processes in preterm infants.

Urine NMR Metabolomics Profile of Preterm Infants With Necrotizing Enterocolitis Over the First Two Months of Life: A Pilot Longitudinal Case-Control Study

Objective: To investigate changes in the urine metabolome of very low birth weight preterm newborns with necrotizing enterocolitis (NEC) and feed intolerance, we conducted a longitudinal study over the first 2 months of life. The metabolome of NEC newborns was compared with two control groups that did not develop NEC: the first one included preterm babies with feed intolerance, while the second one preterm babies with good feed tolerance.

Methods: Newborns developing NEC within the 3 weeks of life were identified as early onset NEC, while the remaining as late onset NEC. Case-control matching was done according to the gestational age (±1 week), birth weight (± 200 g), and postnatal age. A total of 96 urine samples were collected and analyzed. In newborns with NEC, samples were collected before, during and after the diagnosis over the first 2 months of life, while in controls samples were collected as close as possible to the postnatal age of newborns with NEC. Proton nuclear magnetic resonance (¹H NMR) spectroscopy was used for metabolomic analysis. Data were analyzed by univariate and multivariate statistical analysis.

Results: In all the preterm newborns, urine levels of betaine, glycine, succinate, and citrate positively correlated with postnatal age. Suberate and lactate correlated with postnatal age in preterms with NEC and in controls with food intolerance, while N,N-dimethylglycine (N,N-DMG) correlated only in controls with good digestive tolerance. Preterm controls with feed intolerance showed a progressive significant decrease of N-methylnicotinamide and carnitine. Lactate, betaine, myo-inositol, urea, creatinine, and N,N-dimethylglycine discriminated late-onset NEC from controls with good feed tolerance.

Conclusion: Our findings are discussed in terms of contributions from nutritional and clinical managements of patients and gut microbiota.