Gut Microbiota as a Target for Preventive and Therapeutic Intervention against Food Allergy

The gut microbiota plays a pivotal role in immune system development and function. Modification in the gut microbiota composition (dysbiosis) early in life is a critical factor affecting the development of food allergy. Many environmental factors including caesarean delivery, lack of breast milk, drugs, antiseptic agents, and a low-fiber/high-fat diet can induce gut microbiota dysbiosis, and have been associated with the occurrence of food allergy. New technologies and experimental tools have provided information regarding the importance of select bacteria on immune tolerance mechanisms. Short-chain fatty acids are crucial metabolic products of gut microbiota responsible for many protective effects against food allergy. These compounds are involved in epigenetic regulation of the immune system. These evidences provide a foundation for developing innovative strategies to prevent and treat food allergy. Here, we present an overview on the potential role of gut microbiota as the target of intervention against food allergy.

Cow's milk and rice fermented with Lactobacillus paracasei CBA L74 prevent infectious diseases in children: A randomized controlled trial

BACKGROUND & AIM

Fermented foods have been proposed for the prevention of infectious diseases. We evaluated the efficacy of fermented foods in reducing common infectious diseases (CIDs) in children attending daycare.

METHODS

Prospective randomized, double-blind, placebo-controlled trial (registered under Clinical Trials.gov identifier NCT01909128) on healthy children (aged 12-48 months) consuming daily cow's milk (group A) or rice (group B) fermented with Lactobacillus paracasei CBA L74, or placebo (group C) for three months during the winter season. The main study outcome was the proportion of children who experienced at least one CID. All CIDs were diagnosed by family pediatricians. Fecal concentrations of innate (α- and β-defensins and cathelicidin LL-37) and acquired immunity biomarkers (secretory IgA) were also evaluated.

RESULTS

377 children (193 males, 51%) with a mean (SD) age of 32 (10) months completed the study: 137 in group A, 118 in group B and 122 in group C. Intention-to-treat analysis showed that the proportion of children who experienced at least one CID was lower in group A (51.8%) and B (65.9%) compared to group C (80.3%). Per-protocol analysis showed that the proportion of children presenting upper respiratory tract infections was lower in group A (48.2%) and group B (58.5%) compared with group C (70.5%). The proportion of children presenting acute gastroenteritis was also lower in group A (13.1%) and group B (19.5%) compared with group C (31.1%). A net increase of all fecal biomarkers of innate and acquired immunity was observed for groups A and B compared to group C. Moreover, there was a negative association between fecal biomarkers and the occurrence of CID.

CONCLUSION

Dietary supplementation with cow's milk or rice fermented with L. paracasei CBA L74 prevents CIDs in children attending daycare possibly by means of a stimulation of innate and acquired immunity.

Polyunsaturated Fatty Acids Attenuate Diet Induced Obesity and Insulin Resistance, Modulating Mitochondrial Respiratory Uncoupling in Rat Skeletal Muscle

Objectives

Omega (ω)-3 polyunsaturated fatty acids (PUFA) are dietary compounds able to attenuate insulin resistance. Anyway, the precise actions of ω-3PUFAs in skeletal muscle are overlooked. We hypothesized that PUFAs, modulating mitochondrial function and efficiency, would ameliorate pro-inflammatory and pro-oxidant signs of nutritionally induced obesity.

Study Design

To this aim, rats were fed a control diet (CD) or isocaloric high fat diets containing either ω-3 PUFA (FD) or lard (LD) for 6 weeks.

Results

FD rats showed lower weight, lipid gain and energy efficiency compared to LD-fed animals, showing higher energy expenditure and O₂ consumption/CO₂ production. Serum lipid profile and pro-inflammatory parameters in FD-fed animals were reduced compared to LD. Accordingly, FD rats exhibited a higher glucose tolerance revealed by an improved glucose and insulin tolerance tests compared to LD, accompanied by a restoration of insulin signalling in skeletal muscle. PUFAs increased lipid oxidation and reduced energy efficiency in subsarcolemmal mitochondria, and increase AMPK activation, reducing both endoplasmic reticulum and oxidative stress. Increased mitochondrial respiration was related to an increased mitochondriogenesis in FD skeletal muscle, as shown by the increase in PGC1-α and -β.

Conclusions

our data strengthened the association of high dietary ω3-PUFA intake with reduced mitochondrial energy efficiency in the skeletal muscle.

Zinc supplementation reduces morbidity and mortality in very-low-birth-weight preterm neonates: a hospital-based randomized, placebo-controlled trial in an industrialized country

BACKGROUND

Zinc plays a pivotal role in the pathogenesis of many diseases and in body growth. Preterm neonates have high zinc requirements.

OBJECTIVE

The objective of the study was to investigate the efficacy of zinc supplementation in reducing morbidity and mortality in preterm neonates and to promote growth.

DESIGN

This was a prospective, double-blind, randomized controlled study of very-low-birth-weight preterm neonates randomly allocated on the seventh day of life to receive (zinc group) or not receive (control group) oral zinc supplementation. Total prescribed zinc intake ranged from 9.7 to 10.7 mg/d in the zinc group and from 1.3 to 1.4 mg/d in the placebo control group. The main endpoint was the rate of neonates with ≥ 1 of the following morbidities: late-onset sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, periventricular leucomalacia, and retinopathy of prematurity. Secondary outcomes were mortality and body growth.

RESULTS

We enrolled 97 neonates in the zinc group and 96 in the control group. Morbidities were significantly lower in the zinc group (26.8% compared with 41.7%; P = 0.030). The occurrence of necrotizing enterocolitis was significantly higher in the control group (6.3% compared with 0%; P = 0.014). Mortality risk was higher in the placebo control group (RR: 2.37; 95% CI: 1.08, 5.18; P = 0.006). Daily weight gain was similar in the zinc (18.2 ± 5.6 g · kg⁻¹ · d⁻¹) and control (17.0 ± 8.7 g · kg⁻¹ · d⁻¹) groups (P = 0.478).

CONCLUSION

Oral zinc supplementation given at high doses reduces morbidities and mortality in preterm neonates. This trial was registered in the Australian New Zealand Clinical Trial Register as ACTRN12612000823875.

Polymorphisms of tumor necrosis factor-alpha but not MDR1 influence response to medical therapy in pediatric-onset inflammatory bowel disease

AIM

We investigated the contribution of variants of tumour necrosis factor (TNF)-alpha and MDR1 genes in the predisposition and response to medical therapy in a large pediatric cohort of patients with Crohn disease (CD) and ulcerative colitis (UC).

PATIENTS AND METHODS

In this study, 200 patients with CD, 186 patients with UC, 434 parents (217 trios), and 347 healthy unrelated controls were investigated. Single-nucleotide polymorphisms -G308A and -C857T of the TNF-alpha gene and C3435T of the MDR1 gene were investigated and correlated with clinical subphenotypes and efficacy of medical therapy.

RESULTS

The frequency of the -308A allele of the TNF-alpha gene was significantly increased in both patients with CD (15%; odds ratio [OR] = 2.79; P < 0.01) and patients with UC (11%; OR = 1.96; P < 0.003) compared with controls (6%). Carriers of this allele were 27% in CD (OR = 2.94; P < 0.01) and 19% in UC (OR = 1.86; P = 0.015) compared with 11% in healthy controls. No significant difference was found for both the -C857T and C3435T single-nucleotide polymorphisms. With the genotype/phenotype analysis, no correlation in patients with UC with the MDR1 gene was found. CD carriers of the -308A allele had a higher frequency of surgical resection (35% vs 20%; OR = 2.1; P = 0.035) and more frequent resistance to steroids (22% vs 8%; OR = 0.29; P = 0.032) compared with noncarriers. These findings were confirmed by stepwise logistic regression.

CONCLUSIONS

In our pediatric cohort, the promoter -308A polymorphism of TNF-alpha but not the MDR1 gene is significantly involved in the predisposition to both CD and UC. This polymorphism carries a significant reduction in response to steroid therapy, probably leading to a more frequent need for surgical resection.

Differences in DNA methylation profile of Th1 and Th2 cytokine genes are associated with tolerance acquisition in children with IgE-mediated cow's milk allergy

BACKGROUND

Epigenetic changes in DNA methylation could regulate the expression of several allergy-related genes. We investigated whether tolerance acquisition in children with immunoglobulin E (IgE)-mediated cow's milk allergy (CMA) is characterized by a specific DNA methylation profile of Th2 (IL-4, IL-5) and Th1 (IL-10, IFN-γ)-associated cytokine genes.

RESULTS

DNA methylation of CpGs in the promoting regions of genes from peripheral blood mononuclear cells and serum level of IL-4, IL-5, IL-10 and INF-γ were assessed in children with active IgE-mediated CMA (group 1), in children who acquired tolerance to cow's milk proteins (group 2) and in healthy children (group 3). Forty children (24 boys, aged 3 to 18 months) were enrolled: 10 in group 1, 20 in group 2, and 10 in the control group. The DNA methylation profiles clearly separated active CMA patients from healthy controls. We observed an opposite pattern comparing subjects with active IgE-mediated CMA with healthy controls and group 2 children who outgrew CMA. The IL-4 and IL-5 DNA methylation was significantly lower, and IL-10 and INF-γ DNA methylation was higher in active IgE-mediated CMA patients. Gene promoter DNA methylation rates of all cytokines and respective serum levels were strongly correlated. Formula selection significantly influenced cytokine DNA methylation profiles in group 2.

CONCLUSIONS

Tolerance acquisition in children with IgE-mediated CMA is characterized by a distinct Th1 and Th2 cytokine gene DNA methylation pattern. These results suggest that DNA methylation may be a target for CMA prevention and treatment.

Human, donkey and cow milk differently affects energy efficiency and inflammatory state by modulating mitochondrial function and gut microbiota

Different nutritional components are able, by modulating mitochondrial function and gut microbiota composition, to influence body composition, metabolic homeostasis and inflammatory state. In this study, we aimed to evaluate the effects produced by the supplementation of different milks on energy balance, inflammatory state, oxidative stress and antioxidant/detoxifying enzyme activities and to investigate the role of the mitochondrial efficiency and the gut microbiota in the regulation of metabolic functions in an animal model. We compared the intake of human milk, gold standard for infant nutrition, with equicaloric supplementation of donkey milk, the best substitute for newborns due to its nutritional properties, and cow milk, the primary marketed product. The results showed a hypolipidemic effect produced by donkey and human milk intake in parallel with enhanced mitochondrial activity/proton leakage. Reduced mitochondrial energy efficiency and proinflammatory signals (tumor necrosis factor α, interleukin-1 and lipopolysaccharide levels) were associated with a significant increase of antioxidants (total thiols) and detoxifying enzyme activities (glutathione-S-transferase, NADH quinone oxidoreductase) in donkey- and human milk-treated animals. The beneficial effects were attributable, at least in part, to the activation of the nuclear factor erythroid-2-related factor-2 pathway. Moreover, the metabolic benefits induced by human and donkey milk may be related to the modulation of gut microbiota. In fact, milk treatments uniquely affected the proportions of bacterial phyla and genera, and we hypothesized that the increased concentration of fecal butyrate in human and donkey milk-treated rats was related to the improved lipid and glucose metabolism and detoxifying activities.

Butyrate as an effective treatment of congenital chloride diarrhea

BACKGROUND & AIMS

Many therapeutic attempts have demonstrated to be ineffective in reducing the severity of congenital chloride diarrhea and its long-term complications. The short-chain fatty acid butyrate stimulates intestinal water and ion absorption through a variety of mechanisms, including the activation of a parallel Cl-/butyrate and Na+/H+ exchanger. In this case report, we report the therapeutic efficacy of butyrate on an 11-year-old patient affected by congenital chloride diarrhea.

METHODS

The efficacy of increasing doses of oral butyrate (from 50 to 100 mg/kg/day) was investigated through the daily evaluation of stool volume, bowel movements, fecal incontinence, serum, and stool electrolytes concentrations. The modifications in transepithelial intestinal ion transport elicited by butyrate were examined by rectal dialysis study.

RESULTS

A butyrate dose of 100 mg/kg/day induced a normalization of stool pattern and of serum and fecal electrolytes concentration. The rectal dialysis study demonstrated a proabsorptive effect induced by butyrate on Na+, Cl-, and K+ intestinal transport. Butyrate therapy was well tolerated during the entire 12-month observation period, and the stool pattern and fecal and serum ion concentrations remained stable within the normal ranges. No clinical adverse events or episodes of dehydration requiring hospital care were observed.

CONCLUSIONS

Butyrate could be effective in treating congenital chloride diarrhea. It is easily administered, useful in preventing severe dehydration episodes, and may be a promising therapeutic approach for a long-term treatment in this rare and severe condition.

Effects of a Lactobacillus paracasei B21060 based synbiotic on steatosis, insulin signaling and toll-like receptor expression in rats fed a high-fat diet

Insulin resistance (IR) has been identified as crucial pathophysiological factor in the development and progression of non-alcoholic fatty liver disease (NAFLD). Although mounting evidence suggests that perturbation of gut microflora exacerbates the severity of chronic liver diseases, therapeutic approaches using synbiotic has remained overlooked. Here, we show that a synbiotic composed by Lactobacillus paracasei B21060 plus arabinogalactan and fructo-oligosaccharides lessens NAFLD progression in a rat model of high fat feeding. IR and steatosis were induced by administration of high fat diet (HFD) for 6 weeks. Steatosis and hepatic inflammation, Toll-like receptor (TLR) pattern, glucose tolerance, insulin signaling and gut permeability were studied. Liver inflammatory markers were down-regulated in rats receiving the synbiotic, along with an increased expression of nuclear peroxisome proliferator-activated receptors and expression of downstream target genes. The synbiotic improved many aspects of IR, such as fasting response, hormonal homeostasis and glycemic control. Indeed it prevented the impairment of hepatic insulin signaling, reducing the phosphorylation of insulin receptor substrate-1 in Ser 307 and down-regulating suppressor of cytokine signaling 3. Gene expression analysis revealed that in the liver the synbiotic reduced cytokines synthesis and restored the HFD-dysregulated TLR 2, 4 and 9 mRNAs toward a physiological level of expression. The synbiotic preserved gut barrier integrity and reduced the relative amount of Gram-negative Enterobacteriales and Escherichia coli in colonic mucosa. Overall, our data indicate that the L. paracasei B21060 based synbiotic is effective in reducing the severity of liver injury and IR associated with high fat intake, suggesting its possible therapeutic/preventive clinical utilization.

Congenital diarrhoeal disorders: advances in this evolving web of inherited enteropathies

Congenital diarrhoeal disorders (CDDs) represent an evolving web of rare chronic enteropathies, with a typical onset early in life. In many of these conditions, severe chronic diarrhoea represents the primary clinical manifestation, whereas in others diarrhoea is only a component of a more complex multi-organ or systemic disorder. Typically, within the first days of life, diarrhoea leads to a life-threatening condition highlighted by severe dehydration and serum electrolyte abnormalities. Thus, in the vast majority of cases appropriate therapy must be started immediately to prevent dehydration and long-term, sometimes severe, complications. The number of well-characterized disorders attributed to CDDs has gradually increased over the past several years, and many new genes have been identified and functionally related to CDDs, opening new diagnostic and therapeutic perspectives. Molecular analysis has changed the diagnostic scenario in CDDs, and led to a reduction in invasive and expensive procedures. Major advances have been made in terms of pathogenesis, enabling a better understanding not only of these rare conditions but also of more common diseases mechanisms.

Gut Microbiome as Target for Innovative Strategies Against Food Allergy

The dramatic increase in food allergy prevalence and severity globally requires effective strategies. Food allergy derives from a defect in immune tolerance mechanisms. Immune tolerance is modulated by gut microbiota function and structure, and microbiome alterations (dysbiosis) have a pivotal role in the development of food allergy. Environmental factors, including a low-fiber/high-fat diet, cesarean delivery, antiseptic agents, lack of breastfeeding, and drugs can induce gut microbiome dysbiosis, and have been associated with food allergy. New experimental tools and technologies have provided information regarding the role of metabolites generated from dietary nutrients and selected probiotic strains that could act on immune tolerance mechanisms. The mechanisms are multiple and still not completely defined. Increasing evidence has provided useful information on optimal bacterial species/strains, dosage, and timing for intervention. The increased knowledge of the crucial role played by nutrients and gut microbiota-derived metabolites is opening the way to a post-biotic approach in the stimulation of immune tolerance through epigenetic regulation. This review focused on the potential role of gut microbiome as the target for innovative strategies against food allergy.

Zinc Inhibits Cholera Toxin–Induced, but NotEscherichia coliHeat‐Stable Enterotoxin–Induced, Ion Secretion in Human Enterocytes

BACKGROUND

Because zinc deficiency in malnourished children is associated with severe diarrhea, use of zinc supplementation has been proposed as an adjunct to oral rehydration. However, the effects of zinc on enterocyte ion transport are largely unknown. The objective of the present study was to investigate the effects of zinc on transepithelial ion transport under basal conditions and under conditions of enterotoxin-induced ion secretion.

METHODS

Ion transport was investigated by monitoring electrical parameters in human intestinal Caco-2 cells that were mounted in Ussing chambers and exposed to increasing concentrations of zinc, both in the absence and presence of either cholera toxin (CT) or Escherichia coli heat-stable enterotoxin (ST). Intracellular cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) concentrations were also determined.

RESULTS

The addition of zinc to the luminal or basolateral side of enterocytes induced a chloride-dependent, dose-related decrease in short-circuit current, indicating ion absorption. It also resulted in a substantial reduction in CT-induced ion secretion and in cAMP concentration. E. coli ST-induced ion secretion and cGMP concentration were not affected. Ion absorption peaked at 35 mu mol/L zinc, whereas excess zinc load induced active ion secretion.

CONCLUSIONS

By causing a decrease in cAMP concentration, zinc directly promotes ion absorption and substantially reduces CT-induced, but not E. coli ST-induced, ion secretion.

Dietary Interventions to Modulate the Gut Microbiome-How Far Away Are We From Precision Medicine

The importance of the gut microbiome in human health and disease is fully acknowledged. A perturbation in the equilibrium among the different microbial populations living in the gut (dysbiosis) has been associated with the development of several types of diseases. Modulation of the gut microbiome through dietary intervention is an emerging therapeutic and preventive strategy for many conditions. Nevertheless, interpersonal differences in response to therapeutic treatments or dietary regimens are often observed during clinical trials, and recent research has suggested that subject-specific features of the gut microbiota may be responsible. In this review, we summarize recent findings in personalized nutrition, highlighting how individualized characterization of the microbiome may assist in designing ad hoc tailored dietary intervention for disease treatment and prevention. Moreover, we discuss the limitations and challenges encountered in integrating patient-specific microbial data into clinical practice.

Human intestinal cryptosporidiosis: secretory diarrhea and enterotoxic activity in Caco-2 cells

A cell line model to detect enterotoxic effect was used to test fecal specimens of patients with enteric cryptosporidiosis. Fecal samples were obtained from 11 patients with Cryptosporidium diarrhea, and osmotic gap was determined. Caco-2 cell monolayers grown on filters were mounted in Ussing chambers, and electrical parameters were measured before and after the addition of fecal supernatant. A significant increase in short-circuit current was seen in 9 of 11 specimens. The enterotoxic effect was time- and dose-dependent, saturable, and Cl(-)- and Ca(2+)-dependent. Fecal osmotic gap was consistent with secretory diarrhea in the 9 enterotoxin-positive but not in the 2 enterotoxin-negative samples. In conclusion, a cell line model for studying the pathophysiology of enteric cryptosporidiosis was established. Enterotoxic activity was observed in most patients with enteric cryptosporidiosis and was strictly associated with secretory diarrhea.

Results from the pediatric European register for treatment of Helicobacter pylori (PERTH)

BACKGROUND AND AIM

Data on the eradication treatment for childhood Helicobacter pylori are scanty. A register was established on the European Society for Pediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) website to collect data on treatment performed by European pediatricians to ascertain what is practiced in the field.

SUBJECTS

From January 2001 to December 2002, information on 597 children were entered by 23 European Centers, but only data of 518 treated children were completed and analyzed (86.7%, 262 male subjects, median age 9 years, range 1-14). According to their nationality, 226 children were from Southern Europe, 132 from Eastern Europe, 68 from Western Europe, and 4 from northern Europe, 68 from North Africa, and 20 from Asia. At endoscopy, 454 children had gastritis and 64 had ulcer (12.3%). Antibiotic sensitivity, tested in 361 cases, revealed 18% clarithromycin-resistant and 19% metronidazole-resistant H. pylori strains.

RESULTS

Treatment was performed for 1 week in 388 and for 2 weeks in 130 children. Antibiotics were associated with proton pump inhibitors (PPI) in 345 and with bismuth in 121 children. Triple therapy was given to 485 children, dual therapy to 26, quadruple to 7. Follow-up data, by (13)C-Urea-Breath Test or histology or both, were available for 480 children. Overall eradication rate was 65.6%, significantly higher in children with ulcer (79.7%) than without (63.9%, p = .001). When given as first treatment, bismuth-containing triple therapies were more efficacious than PPI-containing ones (77% versus 64%, p = .02, OR 1.88, 95% CI 1.1-3.3). Twenty-seven different treatment regimens were used, but only six were administered to at least 18 children (range 18-157). There was no difference between treatments given for 1 or 2 weeks, or given as first or second therapies.

CONCLUSION

European pediatricians entering data in the register used 27 different regimens. Bismuth-containing therapies resulted in higher eradication rate. Omeprazole-containing triple therapies were the most used although their efficacy was low. Therapies recommended for adults do not appear to be suitable for children.

Faecal calprotectin in suspected paediatric inflammatory bowel disease

OBJECTIVES

The diagnostic accuracy of faecal calprotectin (FC) concentration for paediatric inflammatory bowel disease (IBD) is well described at the population level, but not at the individual level. We reassessed the diagnostic accuracy of FC in children with suspected IBD and developed an individual risk prediction rule using individual patient data.

METHODS

MEDLINE, EMBASE, DARE, and MEDION databases were searched to identify cohort studies evaluating the diagnostic performance of FC in paediatric patients suspected of having IBD. A standard study-level meta-analysis was performed. In an individual patient data meta-analysis, we reanalysed the diagnostic accuracy on a merged patient dataset. Using logistic regression analysis we investigated whether and how the FC value and patient characteristics influence the diagnostic precision. A prediction rule was derived for use in clinical practice and implemented in a spreadsheet calculator.

RESULTS

According to the study-level meta-analysis (9 studies, describing 853 patients), FC has a high overall sensitivity of 0.97 (95% confidence interval [CI] 0.92-0.99) and a specificity of 0.70 (0.59-0.79) for diagnosing IBD. In the patient-level pooled analysis of 742 patients from 8 diagnostic accuracy studies, we calculated that at an FC cutoff level of 50 μg/g there would be 17% (95% CI 15-20) false-positive and 2% (1-3) false-negative results. The final logistic regression model was based on individual data of 545 patients and included both FC level and age. The area under the receiver operating characteristic curve of this derived prediction model was 0.92 (95% CI 0.89-0.94).

CONCLUSIONS

In high-prevalence circumstances, FC can be used as a noninvasive biomarker of paediatric IBD with only a small risk of missing cases. To quantify the individual patients' risk, we developed a simple prediction model based on FC concentration and age. Although the derived prediction rule cannot substitute the clinical diagnostic process, it can help in selecting patients for endoscopic evaluation.

Minimal enteral feeding reduces the risk of sepsis in feed-intolerant very low birth weight newborns

AIMS

To evaluate the efficacy and safety of minimal enteral feeding (MEF) nutritional practice in feed-intolerant very low birth weight (VLBW) infants.

METHODS

A retrospective design using data reported in the clinical charts of VLBW newborns consecutively observed in neonatal intensive care units (NICU) that presents feed intolerance. During the study period, two feeding strategies were adopted: total parenteral nutrition (PN) (group 1) or PN plus MEF (group 2), for at least 24 h. Primary outcome was the time to reach full enteral feeding; secondary outcomes were the occurrence of sepsis, the time to regain birth weight, the length of hospitalization, the occurrence of necrotizing enterocolitis (NEC) Bell stage >II and death.

RESULTS

In total, 102 newborns were evaluated: 51 in group 1, and 51 in group 2. Neonates in group 2 achieved full enteral nutrition earlier (8 days, interquartile range [IQR] 5) compared with subjects receiving total PN (11 days, IQR 5, p < 0.001). A reduction of sepsis episodes was observed in group 2 (15.7%) compared with group 1 (33.3%, p = 0.038). Additionally, subjects in group 2 regained their birth weight and were discharged earlier. The occurrence of NEC and death were similar in the two groups.

CONCLUSION

Minimal enteral feeding in very low birth weight infants presenting feed intolerance reduces the time to reach full enteral feeding and the risk of sepsis. This feeding practice does not increase the risk of necrotizing enterocolitis and death.

Effects of HIV-1 Tat protein on ion secretion and on cell proliferation in human intestinal epithelial cells

BACKGROUND & AIMS

Severe diarrhea and enteropathy of unknown origin are frequent in patients infected with human immunodeficiency type 1 virus (HIV-1). The HIV-1 transactivating factor protein (Tat) is a key factor in the pathogenesis of acquired immunodeficiency syndrome. We investigated whether Tat could directly induce ion secretion and cell damage in enterocytes.

METHODS

Electrical parameters (ion transport studies) were measured in Caco-2 cell monolayers and in human colonic mucosa specimens mounted in Ussing chambers. The effect of Tat on intestinal mucosa integrity was determined by monitoring the transepithelial electrical resistance of Caco-2 cell monolayers. (3)H-thymidine incorporation and cell count were used to evaluate the effect of Tat on cell growth. Intracellular calcium concentrations were measured at the single-cell level using microfluorometry technique.

RESULTS

Tat protein induced ion secretion in Caco-2 cells and in human colonic mucosa similar to that induced by bacterial enterotoxins. It also significantly prevented enterocyte proliferation. In both instances, the effect of Tat was maximum at concentrations within the range detected in the sera of HIV-1-infected patients. Anti-Tat antibodies inhibited both effects. Ion secretion and the antiproliferative effects were mediated by L-type Ca(2+) channels. An increase in intracellular calcium concentration in Caco-2 cells was found after addition of Tat.

CONCLUSIONS

These results indicate that Tat may be involved in HIV-1-related intestinal disease through direct interaction with enterocytes.

Enterotoxic effect of stool supernatant of Cryptosporidium-infected calves on human jejunum

BACKGROUND/AIMS

The clinical pattern of cryptosporidial diarrhea suggests an enterotoxic mechanism. No evidence for this mechanism has been reported thus far. This study aimed to look for enterotoxic effect elaborated by Cryptosporidium.

METHODS

The effects on human intestinal transport of stool supernatant of diarrheal calves infected with Cryptosporidium parvum were examined. Aliquots of centrifuged and filtered stools were added to the mucosal or serosal side of human jejunum obtained from patients undergoing surgery and mounted in Ussing chambers. Electrical parameters were recorded. Stool supernatants of uninfected calves served as a control.

RESULTS

The mucosal addition of 2.5 mg protein of fecal supernatant from diarrheal calves induced a prompt and significant increase in short circuit current with no effects on tissue conductance. The serosal addition of this material and the addition of control supernatant to either side did not induce modifications of electrical parameters. The enterotoxic effect was dose-dependent and saturable. It was reversible by withdrawing the supernatant from the incubation medium. The electrical effect was chloride- and calcium-dependent and was sensitive to heating.

CONCLUSIONS

An enterotoxic activity is present in the stools of Cryptosporidium-infected calves. This activity may be responsible for secretory diarrhea in humans.

Preventive Effect of Cow's Milk Fermented with Lactobacillus paracasei CBA L74 on Common Infectious Diseases in Children: A Multicenter Randomized Controlled Trial

Background: Fermented foods have been proposed to prevent common infectious diseases (CIDs) in children attending day care or preschool.

OBJECTIVES

To investigate the efficacy of dietary supplementation with cow's skim milk fermented with the probiotic Lactobacillus paracasei CBA L74 in reducing CIDs in children attending day care or preschool. Methods: Multicenter, randomized, double-blind, placebo-controlled trial on healthy children (aged 12-48 months) consuming daily 7 grams of cow's skim milk fermented with L. paracasei CBA L74 (group A), or placebo (maltodextrins group B) attending day care or preschool during the winter season. The main outcome was the proportion of children who experienced ≥1 episode of CID during a 3-month follow-up. Fecal biomarkers of innate (α- and β-defensins, cathelicidin) and acquired immunity (secretory IgA) were also monitored. Results: A total of 126 children (71 males, 56%) with a mean (SD) age of 33 (9) months completed the study, 66 in group A and 60 in group B. At intention to treat analysis, the proportion of children presenting ≥1 CID was 60% in group A vs. 83% in group B, corresponding to an absolute risk difference (ARD) of -23% (95% CI: -37% to -9%, p < 0.01). At per-protocol-analysis (PPA), the proportion of children presenting ≥1 CID was 18% in group A vs. 40% in group B, corresponding to an absolute risk difference (ARD) of -22% (95% CI: -37% to -6%, p < 0.01). PPA showed that the proportion of children presenting ≥1 acute gastroenteritis (AGE) was significantly lower in group A (18% vs. 40%, p < 0.05). The ARD for the occurrence of ≥1 AGE was -22% (95% CI: -37% to -6%, p < 0.01) in group A. Similar findings were obtained at PPA regarding the proportion of children presenting ≥1 upper respiratory tract infection (URTI), which was significantly lower in group A (51% vs. 74%, p < 0.05), corresponding to an ARD of -23% (95% CI: -40% to -7%, p < 0.01). Significant changes in innate and acquired immunity biomarkers were observed only in subjects in group A. Conclusions: Dietary supplementation with cow's skim milk fermented with L. paracasei CBA L74 is an efficient strategy in preventing CIDs in children.

Polyphenol-rich virgin olive oil reduces insulin resistance and liver inflammation and improves mitochondrial dysfunction in high-fat diet fed rats

SCOPE

Virgin olive oil is an essential component of the Mediterranean diet. Its antioxidant and anti-inflammatory properties are mainly linked to phenolic contents. This study aims to evaluate the beneficial effects of a polyphenol-rich virgin olive oil (HPCOO) or olive oil without polyphenols (WPOO) in rats fed high-fat diet (HFD).

METHODS AND RESULTS

Male Sprague-Dawley rats were divided into four groups based on the different types of diet: (I) standard diet (STD); (II) HFD; (III) HFD containing WPOO, and (IV) HFD containing HPCOO. HPCOO and WPOO induced a significant improvement of HFD-induced impaired glucose homeostasis (by hyperglycemia, altered oral glucose tolerance, and HOMA-IR) and inflammatory status modulating pro- and anti-inflammatory cytokines (TNF-α, IL-1, and IL-10) and adipokines. Moreover, HPCOO and less extensively WPOO, limited HFD-induced liver oxidative and nitrosative stress and increased hepatic fatty acid oxidation. To study mitochondrial performance, oxidative capacity and energy efficiency were also evaluated in isolated liver mitochondria. HPCOO, but not WPOO, reduced H₂ O₂ release and aconitase activity by decreasing degree of coupling, which plays a major role in the control of mitochondrial reactive oxygen species emission.

CONCLUSION

HPCOO limits HFD-induced insulin resistance, inflammation, and hepatic oxidative stress, preventing nonalcoholic fatty liver disease progression.

The therapeutic efficacy of Bifidobacterium animalis subsp. lactis BB-12® in infant colic: A randomised, double blind, placebo-controlled trial

BACKGROUND

The pathogenesis of infant colic is poorly defined. Gut microbiota seems to be involved, supporting the potential therapeutic role of probiotics.

AIMS

To assess the rate of infants with a reduction of ≥50% of mean daily crying duration after 28 days of intervention with the probiotic Bifidobacterium animalis subsp. lactis BB-12® (BB-12). Secondary outcomes were daily number of crying episodes, sleeping time, number of bowel movements and stool consistency.

METHODS

Randomized controlled trial (RCT) on otherwise healthy exclusively breastfed infants with infant colic randomly allocated to receive BB-12 (1 × 109  CFU/day) or placebo for 28 days. Gut microbiota structure and butyrate, beta-defensin-2 (HBD-2), cathelicidin (LL-37), secretory IgA (sIgA) and faecal calprotectin levels were assessed.

RESULTS

Eighty infants were randomised, 40/group. The rate of infants with reduction of ≥50% of mean daily crying duration was higher in infants treated with BB-12, starting from the end of 2nd week. No infant relapsed when treatment was stopped. The mean number of crying episodes decreased in both groups, but with a higher effect in BB-12 group (-4.7 ± 3.4 vs -2.3 ± 2.2, P < 0.05). Mean daily stool frequency decreased in both groups but the effect was significantly higher in the BB-12 group; stool consistency was similar between the two groups. An increase in Bifidobacterium abundance (with significant correlation with crying time reduction), butyrate and HBD-2, LL-37, sIgA levels associated with a decrease in faecal calprotectin level were observed in the BB-12 group.

CONCLUSIONS

Supplementation with BB-12 is effective in managing infant colic. The effect could derive from immune and non-immune mechanisms associated with a modulation of gut microbiota structure and function.

The role of the commensal microbiota in the regulation of tolerance to dietary allergens

PURPOSE OF REVIEW

We review the evidence that environmental stimuli that perturb naturally selected host-microbe interactions are driving the increasing prevalence of food allergy and examine the mechanisms by which commensal bacteria regulate tolerance to dietary allergens.

RECENT FINDINGS

Antibiotic use and the consumption of a high-fat/low-fiber diet have a major and rapid impact on gut bacterial populations, with long-term consequences for both overall microbial community structure and the regulation of host immunity. Recent work emphasizes the role of mucosa-associated commensal bacteria in eliciting a barrier-protective response critical to preventing allergic sensitization to food. Murine model studies are informing the development of novel live biotherapeutic approaches as an adjunctive therapy to enhance antigen-specific oral desensitization and to promote lasting tolerance in patients with food allergy.

SUMMARY

Strategies based on modulating the composition and/or functionality of the gut microbiome hold promise for the treatment of food allergy.

Therapeutic Effects of Butyrate on Pediatric Obesity: A Randomized Clinical Trial

Importance

The pediatric obesity disease burden imposes the necessity of new effective strategies.

Objective

To determine whether oral butyrate supplementation as an adjunct to standard care is effective in the treatment of pediatric obesity.

Design, Setting, and Participants

A randomized, quadruple-blind, placebo-controlled trial was performed from November 1, 2020, to December 31, 2021, at the Tertiary Center for Pediatric Nutrition, Department of Translational Medical Science, University of Naples Federico II, Naples, Italy. Participants included children aged 5 to 17 years with body mass index (BMI) greater than the 95th percentile.

Interventions

Standard care for pediatric obesity supplemented with oral sodium butyrate, 20 mg/kg body weight per day, or placebo for 6 months was administered.

Main Outcomes and Measures

The main outcome was the decrease of at least 0.25 BMI SD scores at 6 months. The secondary outcomes were changes in waist circumference; fasting glucose, insulin, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, ghrelin, microRNA-221, and interleukin-6 levels; homeostatic model assessment of insulin resistance (HOMA-IR); dietary and lifestyle habits; and gut microbiome structure. Intention-to-treat analysis was conducted.

Results

Fifty-four children with obesity (31 girls [57%], mean [SD] age, 11 [2.91] years) were randomized into the butyrate and placebo groups; 4 were lost to follow-up after receiving the intervention in the butyrate group and 2 in the placebo group. At intention-to-treat analysis (n = 54), children treated with butyrate had a higher rate of BMI decrease greater than or equal to 0.25 SD scores at 6 months (96% vs 56%, absolute benefit increase, 40%; 95% CI, 21% to 61%; P < .01). At per-protocol analysis (n = 48), the butyrate group showed the following changes as compared with the placebo group: waist circumference, -5.07 cm (95% CI, -7.68 to -2.46 cm; P < .001); insulin level, -5.41 μU/mL (95% CI, -10.49 to -0.34 μU/mL; P = .03); HOMA-IR, -1.14 (95% CI, -2.13 to -0.15; P = .02); ghrelin level, -47.89 μg/mL (95% CI, -91.80 to -3.98 μg/mL; P < .001); microRNA221 relative expression, -2.17 (95% CI, -3.35 to -0.99; P < .001); and IL-6 level, -4.81 pg/mL (95% CI, -7.74 to -1.88 pg/mL; P < .001). Similar patterns of adherence to standard care were observed in the 2 groups. Baseline gut microbiome signatures predictable of the therapeutic response were identified. Adverse effects included transient mild nausea and headache reported by 2 patients during the first month of butyrate intervention.

Conclusions and Relevance

Oral butyrate supplementation may be effective in the treatment of pediatric obesity.

Trial Registration

ClinicalTrials.gov Identifier: NCT04620057.