Induction of increased permeability of polarized enterocyte monolayers by enterotoxigenic Escherichia coli heat-labile enterotoxin

Validation of a Human Challenge Model Using an LT-Expressing Enterotoxigenic E. coli Strain (LSN03-016011) and Characterization of Potential Amelioration of Disease by an Investigational Oral Vaccine Candidate (VLA1701)

Controlled human infection models are important tools for the evaluation of vaccines against diseases where an appropriate correlate of protection has not been identified. Enterotoxigenic Escherichia coli (ETEC) strain LSN03-016011/A (LSN03) is an LT enterotoxin and CS17-expressing ETEC strain useful for evaluating vaccine candidates targeting LT-expressing strains. We sought to confirm the ability of the LSN03 strain to induce moderate-to-severe diarrhea in a healthy American adult population, as well as the impact of immunization with an investigational cholera/ETEC vaccine (VLA-1701) on disease outcomes. A randomized, double-blinded pilot study was conducted in which participants received two doses of VLA1701 or placebo orally, one week apart; eight days after the second vaccination, 30 participants (15 vaccinees and 15 placebo recipients) were challenged with approximately 5 × 109 colony-forming units of LSN03. The vaccine was well tolerated, with no significant adverse events. The vaccine also induced serum IgA and IgG responses to LT. After challenge, 11 of the placebo recipients (73.3%; 95%CI: 48.0-89.1) and 7 of the VLA1701 recipients (46.7%; 95%CI: 24.8-68.8) had moderate-to-severe diarrhea (p = 0.26), while 14 placebo recipients (93%) and 8 vaccine recipients (53.3%) experienced diarrhea of any severity, resulting in a protective efficacy of 42.9% (p = 0.035). In addition, the vaccine also appeared to provide protection against more severe diarrhea (p = 0.054). Vaccinees also tended to shed lower levels of the LSN03 challenge strain compared to placebo recipients (p = 0.056). In addition, the disease severity score was lower for the vaccinees than for the placebo recipients (p = 0.046). In summary, the LSN03 ETEC challenge strain induced moderate-to-severe diarrhea in 73.3% of placebo recipients. VLA1701 vaccination ameliorated disease severity, as observed by several parameters, including the percentage of participants experiencing diarrhea, as well as stool frequency and ETEC severity scores. These data highlight the potential value of LSN03 as a suitable ETEC challenge strain to evaluate LT-based vaccine targets (NCT03576183).

Effects of Catecholamine Stress Hormones Norepinephrine and Epinephrine on Growth, Antimicrobial Susceptibility, Biofilm Formation, and Gene Expressions of Enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli (ETEC) is a significant contributor to diarrhea. To determine whether ETEC-catecholamine hormone interactions contribute to the development of diarrhea, we tested the effects of catecholamine hormones acting on ETEC in vitro. The results showed that in the presence of norepinephrine (NE) and epinephrine (Epi), the growth of 9 out of 10 ETEC isolates was promoted, the MICs of more than 60% of the isolates to 6 antibiotics significantly increased, and the biofilm formation ability of 10 ETEC isolates was also promoted. In addition, NE and Epi also significantly upregulated the expression of the virulence genes feaG, estA, estB, and elt. Transcriptome analysis revealed that the expression of 290 genes was affected by NE. These data demonstrated that catecholamine hormones may augment the diarrhea caused by ETEC.

Circulation of enterotoxigenic Escherichia coli (ETEC) isolates expressing CS23 from the environment to clinical settings

IMPORTANCE

The importance of clean water cannot be overstated. It is a vital resource for maintaining health and well-being. Unfortunately, water sources contaminated with fecal discharges from animal and human origin due to a lack of wastewater management pose a significant risk to communities, as they can become a means of transmission of pathogenic bacteria like enterotoxigenic E. coli (ETEC). ETEC is frequently found in polluted water in countries with a high prevalence of diarrheal diseases, such as Bolivia. This study provides novel insights into the circulation of ETEC between diarrheal cases and polluted water sources in areas with high rates of diarrheal disease. These findings highlight the Choqueyapu River as a potential reservoir for emerging pathogens carrying antibiotic-resistance genes, making it a crucial area for monitoring and intervention. Furthermore, the results demonstrate the feasibility of a low-cost, high-throughput method for tracking bacterial pathogens in low- and middle-income countries, making it a valuable tool for One Health monitoring efforts.

Controlled Human Infection Models To Accelerate Vaccine Development

The timelines for developing vaccines against infectious diseases are lengthy, and often vaccines that reach the stage of large phase 3 field trials fail to provide the desired level of protective efficacy. The application of controlled human challenge models of infection and disease at the appropriate stages of development could accelerate development of candidate vaccines and, in fact, has done so successfully in some limited cases. Human challenge models could potentially be used to gather critical information on pathogenesis, inform strain selection for vaccines, explore cross-protective immunity, identify immune correlates of protection and mechanisms of protection induced by infection or evoked by candidate vaccines, guide decisions on appropriate trial endpoints, and evaluate vaccine efficacy. We prepared this report to motivate fellow scientists to exploit the potential capacity of controlled human challenge experiments to advance vaccine development. In this review, we considered available challenge models for 17 infectious diseases in the context of the public health importance of each disease, the diversity and pathogenesis of the causative organisms, the vaccine candidates under development, and each model's capacity to evaluate them and identify correlates of protective immunity. Our broad assessment indicated that human challenge models have not yet reached their full potential to support the development of vaccines against infectious diseases. On the basis of our review, however, we believe that describing an ideal challenge model is possible, as is further developing existing and future challenge models.

The role of CFA/I in adherence and toxin delivery by ETEC expressing multiple colonization factors in the human enteroid model

Enterotoxigenic Escherichia coli (ETEC) is a primary causative agent of diarrhea in travelers and young children in low-to-middle-income countries (LMICs). ETEC adhere to intestinal epithelia via colonization factors (CFs) and secrete heat-stable toxin (ST) and/or heat-labile toxin (LT), causing dysregulated cellular ion transport and water secretion. ETEC isolates often harbor genes encoding more than one CF that are targets as vaccine antigens. CFA/I is a major CF that is associated with ETEC that causes moderate-to-severe diarrhea and plays an important role in pathogenesis. The Global Enteric Multicenter Study finding that 78% of CFA/I-expressing ETEC also encode the minor CF CS21 prompted investigation of the combined role of these two CFs. Western blots and electron microscopy demonstrated growth media-dependent and strain-dependent differences in CFA/I and CS21 expression. The critical role of CFA/I in adherence by ETEC strains expressing CFA/I and CS21 was demonstrated using the human enteroid model and a series of CFA/I- and CS21-specific mutants. Furthermore, only anti-CFA/I antibodies inhibited adherence by global ETEC isolates expressing CFA/I and CS21. Delivery of ST and resulting cGMP secretion was measured in supernatants from infected enteroid monolayers, and strain-specific ST delivery and time-dependent cGMP production was observed. Interestingly, cGMP levels were similar across wildtype and CF-deficient strains, reflecting a limitation of this static aerobic infection model. Despite adherence by ETEC and delivery of ST, the enteroid monolayer integrity was not disrupted, as shown by the lack of decrease in transepithelial electrical resistance and the lack of IL-8 cytokines produced during infection. Taken together, these data demonstrate that targeting CFA/I in global clinical CFA/I-CS21 strains is sufficient for adherence inhibition, supporting a vaccine strategy that focuses on blocking major CFs. In addition, the human enteroid model has significant utility for the study of ETEC pathogenesis and evaluation of vaccine-induced functional antibody responses.

Lentils and Yeast Fibers: A New Strategy to Mitigate Enterotoxigenic Escherichia coli (ETEC) Strain H10407 Virulence?

Dietary fibers exhibit well-known beneficial effects on human health, but their anti-infectious properties against enteric pathogens have been poorly investigated. Enterotoxigenic Escherichia coli (ETEC) is a major food-borne pathogen that causes acute traveler’s diarrhea. Its virulence traits mainly rely on adhesion to an epithelial surface, mucus degradation, and the secretion of two enterotoxins associated with intestinal inflammation. With the increasing burden of antibiotic resistance worldwide, there is an imperious need to develop novel alternative strategies to control ETEC infections. This study aimed to investigate, using complementary in vitro approaches, the inhibitory potential of two dietary-fiber-containing products (a lentil extract and yeast cell walls) against the human ETEC reference strain H10407. We showed that the lentil extract decreased toxin production in a dose-dependent manner, reduced pro-inflammatory interleukin-8 production, and modulated mucus-related gene induction in ETEC-infected mucus-secreting intestinal cells. We also report that the yeast product reduced ETEC adhesion to mucin and Caco-2/HT29-MTX cells. Both fiber-containing products strengthened intestinal barrier function and modulated toxin-related gene expression. In a complex human gut microbial background, both products did not elicit a significant effect on ETEC colonization. These pioneering data demonstrate the promising role of dietary fibers in controlling different stages of the ETEC infection process.

Enterotoxigenic Escherichia coli (ETEC) vaccines: Priority activities to enable product development, licensure, and global access

Diarrhoeal disease attributable to enterotoxigenic Escherichia coli (ETEC) causes substantial morbidity and mortality predominantly in paediatric populations in low- and middle-income countries. In addition to acute illness, there is an increasing appreciation of the long-term consequences of enteric infections, including ETEC, on childhood growth and development. Provision of potable water and sanitation and appropriate clinical care for acute illness are critical to reduce the ETEC burden. However, these interventions are not always practical and may not achieve equitable and sustainable coverage. Vaccination may be the most cost-effective and equitable means of primary prevention; however, additional data are needed to accelerate the investment and guide the decision-making process for ETEC vaccines. First, to understand and quantify the ETEC disease burden, additional data are needed on the association between ETEC infection and physical and cognitive stunting as well as delayed educational attainment. Furthermore, the role of inappropriate or inadequate antibiotic treatment of ETEC-attributable diarrhoea may contribute to the development of antimicrobial resistance (AMR) and needs further elucidation. An ETEC vaccine that mitigates acute diarrhoeal illness and minimizes the longer-term disease manifestations could have significant public health impact and be a cost-effective countermeasure. Herein we review the ETEC vaccine pipeline, led by candidates compatible with the general parameters of the Preferred Product Characteristics (PPC) recently developed by the World Health Organization. Additionally, we have developed an ETEC Vaccine Development Strategy to provide a framework to underpin priority activities for researchers, funders and vaccine manufacturers, with the goal of addressing globally unmet data needs in the areas of research, product development, and policy, as well as commercialization and delivery. The strategy also aims to guide prioritization and co-ordination of the priority activities needed to minimize the timeline to licensure and use of ETEC vaccines, especially in in low- and middle-income countries, where they are most urgently needed.

Critical Role of Zinc in a New Murine Model of Enterotoxigenic Escherichia coli Diarrhea

Enterotoxigenic Escherichia coli (ETEC) is a major cause of traveler's diarrhea as well as of endemic diarrhea and stunting in children in developing areas. However, a small-mammal model has been badly needed to better understand and assess mechanisms, vaccines, and interventions. We report a murine model of ETEC diarrhea, weight loss, and enteropathy and investigate the role of zinc in the outcomes. ETEC strains producing heat-labile toxins (LT) and heat-stable toxins (ST) that were given to weaned C57BL/6 mice after antibiotic disruption of normal microbiota caused growth impairment, watery diarrhea, heavy stool shedding, and mild to moderate intestinal inflammation, the latter being worse with zinc deficiency. Zinc treatment promoted growth in zinc-deficient infected mice, and subinhibitory levels of zinc reduced expression of ETEC virulence genes cfa1, cexE, sta2, and degP but not of eltA in vitro Zinc supplementation increased shedding and the ileal burden of wild-type (WT) ETEC but decreased shedding and the tissue burden of LT knockout (LTKO) ETEC. LTKO ETEC-infected mice had delayed disease onset and also had less inflammation by fecal myeloperoxidase (MPO) assessment. These findings provide a new murine model of ETEC infection that can help elucidate mechanisms of growth, diarrhea, and inflammatory responses as well as potential vaccines and interventions.

Enterotoxigenic Escherichia coli and probiotics in swine: what the bleep do we know?

The concept of certain microorganisms conferring direct benefits to the host relates to the term "probiotic". Probiotics are microorganisms, bacteria, or yeast that when administered orally in sufficient quantity can counteract the effect of pathogenic microorganisms. The gastrointestinal (GI) tract is the site where probiotics are believed to play the most important role. The proposed effects of probiotics include antagonism of pathogens, interference with adherence, competition for nutrients, enterotoxin inactivation, modulation of the immune response, and strengthening of the intestinal barrier. From birth to postweaning, piglets are very sensitive to gut colonisation by pathogens. Enterotoxigenic Escherichia coli represents one of the most common agents of swine diarrhoea. The enterotoxins produced by this E. coli virotype are responsible for the loss of electrolytes and water observed following infection. This review addresses more specifically the studies done during the last 10 years deciphering the molecular mechanisms at play between host cell and probiotic interactions in the swine GI tract.

L-Glutamine and L-arginine protect against enterotoxigenic Escherichia coli infection via intestinal innate immunity in mice

Dietary glutamine (Gln) or arginine (Arg) supplementation is beneficial for intestinal health; however, whether Gln or Arg may confer protection against Enterotoxigenic Escherichia coli (ETEC) infection is not known. To address this, we used an ETEC-infected murine model to investigate the protective effects of Gln and Arg. Experimentally, we pre-treated mice with designed diet of Gln or Arg supplementation prior to the oral ETEC infection and then assessed mouse mortality and intestinal bacterial burden. We also determined the markers of intestinal innate immunity in treated mice, including secretory IgA response (SIgA), mucins from goblet cells, as well as antimicrobial peptides from Paneth cells. ETEC colonized in mouse small intestine, including duodenum, jejunum, and ileum, and inhibited the mRNA expression of intestinal immune factors, such as polymeric immunoglobulin receptor (pIgR), cryptdin-related sequence 1C (CRS1C), and Reg3γ. We found that dietary Gln or Arg supplementation decreased bacterial colonization and promoted the activation of innate immunity (e.g., the mRNA expression of pIgR, CRS1C, and Reg3γ) in the intestine of ETEC-infected mice. Our results suggest that dietary arginine or glutamine supplementation may inhibit intestinal ETEC infection through intestinal innate immunity.

Animal Enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli (ETEC) is the most common cause of E. coli diarrhea in farm animals. ETEC are characterized by the ability to produce two types of virulence factors: adhesins that promote binding to specific enterocyte receptors for intestinal colonization and enterotoxins responsible for fluid secretion. The best-characterized adhesins are expressed in the context of fimbriae, such as the F4 (also designated K88), F5 (K99), F6 (987P), F17, and F18 fimbriae. Once established in the animal small intestine, ETEC produce enterotoxin(s) that lead to diarrhea. The enterotoxins belong to two major classes: heat-labile toxins that consist of one active and five binding subunits (LT), and heat-stable toxins that are small polypeptides (STa, STb, and EAST1). This review describes the disease and pathogenesis of animal ETEC, the corresponding virulence genes and protein products of these bacteria, their regulation and targets in animal hosts, as well as mechanisms of action. Furthermore, vaccines, inhibitors, probiotics, and the identification of potential new targets by genomics are presented in the context of animal ETEC.

Proteome analysis for the global proteins in the jejunum tissues of enterotoxigenic Escherichia coli -infected piglets

Enterotoxigenic Escherichia coli (ETEC) is a common cause of diarrhea in humans and livestock. In this study, isobaric tags for relative and absolute quantitation (iTRAQ) combined with multidimensional liquid chromatography (LC) and MS analysis was used for screening the differentially expressed proteins in piglet jejunum after ETEC infection. Totally 1,897 proteins were identified with quantitative information in piglet jejunum. We identified 92 differentially expressed proteins in ETEC-induced diarrhea, of which 30 were up regulated and 62 down regulated. Most of the differentially expressed proteins were involved in intestinal function of binding, metabolic process, catalytic activity and immune responses. The inhibition of intestinal immune responses in the jejunum in ETEC-induced diarrhea was also validated by immunobloting and RT-PCR. Our study is the first attempt to analyze the protein profile of ETEC-infected piglets by quantitative proteomics, and our findings could provide valuable information with respect to better understanding the host response to ETEC infection.

Colostrum whey down-regulates the expression of early and late inflammatory response genes induced byEscherichia coliandSalmonella entericaTyphimurium components in intestinal epithelial cells

Pathogenic invasion byEscherichia coliandSalmonellaeremains a constant threat to the integrity of the intestinal epithelium and can rapidly induce inflammatory responses. At birth, colostrum consumption exerts numerous beneficial effects on the properties of intestinal epithelial cells and protects the gastrointestinal tract of newborns from pathogenic invasion. The present study aimed to investigate the effect of colostrum on the early and late inflammatory responses induced by pathogens. The short-term (2 h) and long-term (24 h) effects of exposure to heat-killed (HK)E. coliandSalmonella entericaTyphimurium on gene expression in the porcine intestinal epithelial cell (IPEC-J2) model were first evaluated by microarray and quantitative PCR analyses. Luciferase assays were performed using a NF-κB-luc reporter construct to investigate the effect of colostrum whey treatment on the activation of NF-κB induced by HK bacteria. Luciferase assays were also performed using NF-κB-luc, IL-8-luc and IL-6-luc reporter constructs in human colon adenocarcinoma Caco-2/15 cells exposed to dose–response stimulations with HK bacteria and colostrum whey. Bovine colostrum whey treatment decreased the expression of early and late inflammatory genes induced by HK bacteria in IPEC-J2, as well as the transcriptional activation of NF-κB-luc induced by HK bacteria. Unlike that with colostrum whey, treatment with other milk fractions failed to decrease the activation of NF-κB-luc induced by HK bacteria. Lastly, the reduction of the HK bacteria-induced activation of NF-κB-luc, IL-8-luc and IL-6-luc by colostrum whey was dose dependent. The results of the present study indicate that bovine colostrum may protect and preserve the integrity of the intestinal mucosal barrier in the host by controlling the expression levels of early and late inflammatory genes following invasion by enteric pathogens.

Escherichia coli STb enterotoxin dislodges claudin-1 from epithelial tight junctions

Enterotoxigenic Escherichia coli produce various heat-labile and heat-stable enterotoxins. STb is a low molecular weight heat-resistant toxin responsible for diarrhea in farm animals, mainly young pigs. A previous study demonstrated that cells having internalized STb toxin induce epithelial barrier dysfunction through changes in tight junction (TJ) proteins. These modifications contribute probably to the diarrhea observed. To gain insight into the mechanism of increased intestinal permeability following STb exposure we treated human colon cells (T84) with purified STb toxin after which cells were harvested and proteins extracted. Using a 1% Nonidet P-40-containing solution we investigated the distribution of claudin-1, a major structural and functional TJ protein responsible for the epithelium impermeability, between membrane (NP40-insoluble) and the cytoplasmic (NP-40 soluble) location. Using immunoblot and confocal microscopy, we observed that treatment of T84 cell monolayers with STb induced redistribution of claudin-1. After 24 h, cells grown in Ca⁺⁺-free medium treated with STb showed about 40% more claudin-1 in the cytoplasm compare to the control. Switching from Ca⁺⁺-free to Ca⁺⁺-enriched medium (1.8 mM) increased the dislodgement rate of claudin-1 as comparable quantitative delocalization was observed after only 6 h. Medium supplemented with the same concentration of Mg⁺⁺ or Zn⁺⁺ did not affect the dislodgement rate compared to the Ca⁺⁺-free medium. Using anti-phosphoserine and anti-phosphothreonine antibodies, we observed that the loss of membrane claudin-1 was accompanied by dephosphorylation of this TJ protein. Overall, our findings showed an important redistribution of claudin-1 in cells treated with STb toxin. The loss of phosphorylated TJ membrane claudin-1 is likely to be involved in the increased permeability observed. The mechanisms by which these changes are brought about remain to be elucidated.

Recent advances in understanding enteric pathogenic Escherichia coli

Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.

Escherichia coli heat-stable toxin b impairs intestinal epithelial barrier function by altering tight junction proteins

Escherichia coli heat-stable toxin b (STb) causes diarrhea in animals. STb binds to sulfatide, its receptor, and is then internalized. In the cytoplasm, through a cascade of events, STb triggers the opening of ion channels, allowing ion secretion and water loss and leading to diarrhea. Tight junctions (TJs) are well known for controlling paracellular traffic of ions and water by forming a physical intercellular barrier in epithelial cells, and some bacterial toxins are known to affect adversely TJs. The present study aimed at determining the effect of STb on TJs. T84 cells were treated for 24 h with purified STb and a nontoxic STb mutant (D30V). Transepithelial resistance (TER), paracellular flux marker, and confocal microscopy were used to analyze the effect of STb on TJs. Purified STb caused a significant reduction of TER parallel to an increase in paracellular permeability compared to the results seen in untreated cells or mutant D30V. The increased paracellular permeability was associated with a marked alteration of F-actin stress fibers. F-actin filament dissolution and condensation were accompanied by redistribution and/or fragmentation of ZO-1, claudin-1, and occludin. These changes were also observed following treatment of T84 cells with an 8-amino-acid peptide found in the STb sequence corresponding to a consensus sequence of Vibrio cholerae Zot toxin. These effects were not observed with a scrambled peptide or mutant D30V. Our findings indicate that STb induces epithelial barrier dysfunction through changes in TJ proteins that could contribute to diarrhea.

The B subunit of an AB5 toxin produced by Salmonella enterica serovar Typhi up-regulates chemokines, cytokines, and adhesion molecules in human macrophage, colonic epithelial, and brain microvascular endothelial cell lines

The principal function of bacterial AB5 toxin B subunits is to interact with glycan receptors on the surfaces of target cells and mediate the internalization of holotoxin. However, B subunit-receptor interactions also have the potential to impact cell signaling pathways and, in so doing, contribute to pathogenesis independently of the catalytic (toxic) A subunits. Various Salmonella enterica serovars, including Salmonella enterica serovar Typhi, encode an AB5 toxin (ArtAB), the A subunit of which is an ADP-ribosyltransferase related to the S1 subunit of pertussis toxin. However, although the A subunit is able to catalyze ADP-ribosylation of host G proteins, a cytotoxic phenotype has yet to be identified for the holotoxin. We therefore examined the capacity of the purified B subunit (ArtB) from S. Typhi to elicit cytokine, chemokine, and adhesion molecule responses in human macrophage (U937), colonic epithelial (HCT-8) cell, and brain microvascular endothelial cell (HBMEC) lines. Secretion of the chemokines monocyte chemotactic protein 1 (MCP-1) and interleukin 8 (IL-8) was increased in all three tested cell lines, with macrophage inflammatory protein 1α (MIP-1α), MIP-1β, and granulocyte colony-stimulating factor (G-CSF) also significantly increased in U937 cells. ArtB also upregulated the cytokines tumor necrosis factor alpha (TNF-α) and IL-6 in HBMECs and HCT-8 cells, but not in U937 cells, while intercellular adhesion molecule 1 (ICAM-1) was upregulated in HCT-8 and U937 cells and vascular cell adhesion molecule 1 (VCAM-1) was upregulated in HBMECs. Thus, ArtB may contribute to pathogenesis independently of the A subunit by promoting and maintaining a strong inflammatory response at the site of infection.

Supplementation with 200 mg/day docosahexaenoic acid from mid-pregnancy through lactation improves the docosahexaenoic acid status of mothers with a habitually low fish intake and of their infants

BACKGROUND/AIMS

The supply of docosahexaenoic acid (DHA, 22:6omega-3), important for fetal/infant neurodevelopment, depends on the maternal fatty acid (FA) status, which may be marginal in central Europe. Therefore, we investigated the effect of a daily vitamin/mineral supplement with and without 200 mg DHA from mid-pregnancy through lactation on the DHA concentrations in maternal and infant red blood cell phospholipids (RBC%), and in breast milk FA (%).

METHODS

At 21 weeks' gestation, 144 women were enrolled into a randomised, double-blind clinical trial receiving daily: (1) a basic vitamin-mineral supplement (Vit/Min group), (2) Vit/Min plus 4.5 g fructo-oligosaccharide (FOS group), or (3) Vit/Min plus 4.5 g FOS plus 200 mg fish oil-derived DHA (DHA-FOS group). FAs were determined by capillary gas-liquid chromatography.

RESULTS

While maternal RBC-DHA% at enrolment was not different, at 37 weeks gestation, and 3 months after delivery RBC-DHA% were significantly higher in the DHA-FOS group. The breast milk DHA% was twice as high in the DHA-FOS group (0.50%) than in the two others (0.25 %) (p < 0.001), and the ratio ARA/DHA in the DHA-FOS group was 1.0 +/- 0.43, in the others 2.1 +/- 0.43 (p < 0.001). The RBC-DHA% of the infants in the DHA-FOS group was also significantly higher, and correlated significantly with maternal RBC-DHA% before and 3 months after delivery.

CONCLUSIONS

In central Europe, a dose of 200 mg/day DHA from mid-pregnancy through lactation seems appropriate to improve the DHA status of mothers and infants.