Kirsi Laitinen

Host remodeling of the gut microbiome and metabolic changes during pregnancy.

Many of the immune and metabolic changes occurring during normal pregnancy also describe metabolic syndrome. Gut microbiota can cause symptoms of metabolic syndrome in nonpregnant hosts. Here, to explore their role in pregnancy, we characterized fecal bacteria of 91 pregnant women of varying prepregnancy BMIs and gestational diabetes status and their infants. Similarities between infant-mother microbiotas increased with childrens age, and the infant microbiota was unaffected by mothers health status. Gut microbiota changed dramatically from first (T1) to third (T3) trimesters, with vast expansion of diversity between mothers, an overall increase in Proteobacteria and Actinobacteria, and reduced richness. T3 stool showed strongest signs of inflammation and energy loss; however, microbiome gene repertoires were constant between trimesters. When transferred to germ-free mice, T3 microbiota induced greater adiposity and insulin insensitivity compared to T1. Our findings indicate that host-microbial interactions that impact host metabolism can occur and may be beneficial in pregnancy.

The human milk microbiome changes over lactation and is shaped by maternal weight and mode of delivery

BACKGROUND Breast milk is recognized as the most important postpartum element in metabolic and immunologic programming of health of neonates. The factors influencing the milk microbiome and the potential impact of microbes on infant health have not yet been uncovered. OBJECTIVE Our objective was to identify pre- and postnatal factors that can potentially influence the bacterial communities inhabiting human milk. DESIGN We characterized the milk microbial community at 3 different time points by pyrosequencing and quantitative polymerase chain reaction in mothers (n = 18) who varied in BMI, weight gain, and mode of delivery. RESULTS We found that the human milk microbiome changes over lactation. Weisella, Leuconostoc, Staphylococcus, Streptococcus, and Lactococcus were predominant in colostrum samples, whereas in 1- and 6-mo milk samples the typical inhabitants of the oral cavity (eg, Veillonella, Leptotrichia, and Prevotella) increased significantly. Milk from obese mothers tended to contain a different and less diverse bacterial community compared with milk from normal-weight mothers. Milk samples from elective but not from nonelective mothers who underwent cesarean delivery contained a different bacterial community than did milk samples from individuals giving birth by vaginal delivery, suggesting that it is not the operation per se but rather the absence of physiological stress or hormonal signals that could influence the microbial transmission process to milk. CONCLUSIONS Our results indicate that milk bacteria are not contaminants and suggest that the milk microbiome is influenced by several factors that significantly skew its composition. Because bacteria present in breast milk are among the very first microbes entering the human body, our data emphasize the necessity to understand the biological role that the milk microbiome could potentially play for human health.

The impact of perinatal probiotic intervention on the development of overweight and obesity: follow-up study from birth to 10 years

Background:The achievements in combating the increasing trend of overweight and obesity have thus far been inadequate. The recently discovered instrumental role of the gut microbiota in host metabolism may offer a novel target in the prevention and management of obesity.Objective:To evaluate the impact of perinatal probiotic intervention on childhood growth patterns and the development of overweight during a 10-year follow-up.Patients and methods:Altogether 159 women were randomized and double-blinded to receive probiotics (1 × 1010 colony-forming units of Lactobacillus rhamnosus GG, ATCC 53103) or placebo 4 weeks before expected delivery; the intervention extending for 6 months postnatally. Anthropometric measurements of the children were taken at the ages of 3, 6, 12 and 24 months and at 4, 7 and 10 years in 113 (72%) children.Results:The excessive weight gain was detected to be two-parted; the initial phase of excessive weight gain initiating during fetal period and continuing until 24–48 months of age and a second phase of excessive weight gain starting after the age of 24–48 months. The perinatal probiotic intervention appeared to moderate the initial phase of excessive weight gain, especially among children who later became overweight, but not the second phase of excessive weight gain, the impact being most pronounced at the age of 4 years (P=0.063, analysis of variance for repeated measures). The effect of intervention was also shown as a tendency to reduce the birth-weight-adjusted mean body mass index at the age of 4 years (P=0.080, analysis of covariance).Conclusions:Early gut microbiota modulation with probiotics may modify the growth pattern of the child by restraining excessive weight gain during the first years of life. This novel observation calls for further epidemiological and clinical trials, with precise data on early growth patterns and on confounding factors influencing weight development.

Maternal breast‐milk and intestinal bifidobacteria guide the compositional development of the Bifidobacterium microbiota in infants at risk of allergic disease

Background The sources and the impact of maternal bacteria on the initial inoculum of the intestinal microflora of newborn infants remain elusive.

Breast Milk: A Source of Bifidobacteria for Infant Gut Development and Maturation?

Background: The establishment of gut microbiota is a stepwise process contributing to gut development and maturation of the immune system. Aberrant gut microbiota at an early age may predispose to disease later in life. Breast-fed infants harbor a characteristic intestinal microbiota dominated by bifidobacteria. Objectives: To assess, using molecular techniques (PCR), whether human milk contains bifidobacteria and to determine the bifidobacterial species present. Methods: The presence of bifidobacteria in breast milk samples (n = 20) was qualitatively and quantitatively determined by using PCR and real-time PCR, respectively. Results: Breast milk samples contained bifidobacteria. Bifidobacterium longum was the most widely found species followed by Bifidobacterium animalis, Bifidobacterium bifidum and Bifidobacterium catenulatum. Conclusion: Breast milk contains bifidobacteria and specific Bifidobacterium species that may promote healthy microbiota development.

Bifidobacterium and Lactobacillus DNA in the human placenta.

Aims:  Bifidobacteria and lactobacilli are part of the human normal intestinal microbiota and may possibly be transferred to the placenta. It was hypothesized that intestinal bacteria or their components are present in the placenta and that the foetus may be exposed to them. We investigated the presence of bifidobacteria and lactobacilli and their DNA in the human placenta.

Impact of maternal atopy and probiotic supplementation during pregnancy on infant sensitization: a double‐blind placebo‐controlled study

Background The effects of breastfeeding and probiotics on infant sensitization still remain discrepant.

Impact of dietary counselling on nutrient intake during pregnancy: a prospective cohort study

The aim of this study was to assess the impact of dietary counselling combined with the provision of food products on food and nutrient intake in pregnant women. We carried out a prospective cohort study of healthy and atopic pregnant women (n 209), who were randomized into dietary intervention and control groups. The intervention group received dietary counselling and food products to modify the fat composition of their diet to meet current recommendations. Three-day food records were collected during each trimester of pregnancy. Women in the intervention group consumed more vegetables, fruits, soft margarines and vegetable oils and less butter than those in the control group during the course of pregnancy (P<0.05). The main distinction between the groups in nutrient intake over the pregnancy was attributable to a higher energy intake (% energy) of PUFA by 0.5%energy (95% CI 0.1, 0.8) and to a lower intake of SFA by 0.8 % energy (95% CI -1.4, -0.4) in the intervention group. Dietary intake of vitamin E was 1.4 mg (95% CI 0.6, 2.2), folate 20.9 microg (95% CI 0.8, 41.0) and ascorbic acid 19.8 mg (95 % CI 3.5, 36.0) higher in the intervention group compared to the controls, while no differences in other nutrients were detected. Dietary counselling combined with the provision of food products during pregnancy is of importance in modifying food and nutrient intake, with potential health benefits.

Maternal weight and excessive weight gain during pregnancy modify the immunomodulatory potential of breast milk.

Introduction:Breast milk is an optimal source of nutrition for infants. It contains bioactive components including bacteria that support the microbial colonization and immune system development of the infant. The determinants of human milk composition remain poorly understood, although maternal nutritional and immunological status as well as lifestyle and dietary habits seem to have an impact.Methods:The subjects selected were women from a prospective follow-up study categorized by BMI. Milk samples were taken after delivery and at 1 and 6 mo later for analysis of composition in regard to transforming growth factor (TGF)-β2, soluble CD14 (sCD14), cytokines, and microbiota.Results:TGF-β2 and sCD14 levels in the breast milk of overweight mothers tended to be lower than the levels in that of normal-weight mothers. Also, higher levels of Staphylococcus group bacteria and lower levels of Bifidobacterium group bacteria were detected in overweight mothers as compared with normal-weight ones. The prevalence of Akkermansia muciniphila–type bacteria was also higher in overweight mothers, and the numbers of these bacteria were related to the interleukin (IL)-6 concentration in the colostrum, which was in turn related to lower counts of Bifidobacterium group bacteria in the breast milk of overweight women.Discussion:Complex interactions of cytokines and microbiota in breast milk guide the microbiological, immunological, and metabolic programming of infant health. Our data may indicate the presence of an additional mechanism that may explain the heightened risk of obesity for infants of overweight and excessive weight gain mothers.

Distinct gut microbiota in southeastern African and northern European infants.

Background and Objective: The intestinal microbiota composition in infants reflects the early environment. Our objective was to compare the gut microbiota in 6-month-old infants living in rural Malawi with children of the same age living in urban Finland, both being breast-fed and having an age-appropriate diet typical for each area. Methods: Malawian 6-month-old infants (n = 44) were compared with Finnish infants (n = 31) of the same age. In both cohorts, infant stool samples were available for microbiota characterization by flow cytometry-fluorescent in situ hybridization and quantitative polymerase chain reaction methods. Results: Bifidobacteria were dominant at 6 months of age in all of the infants, although in greater proportions in Malawian (70.8%) than in Finnish infants (46.8%; P < 0.001). Additional distinctions in bacterial group composition comprised Bacteroides-Prevotella (17.2% vs 4.7%; P < 0.001) and Clostridium histolyticum (4.4% vs 2.8%; P = 0.01), respectively. The species Bifidobacterium adolescentis, Clostridium perfringens, and Staphylococcus aureus were absent in Malawian but detected in Finnish infants. Conclusions: The gut microbiota of 6-month-old infants in a low-income country differs significantly from that in a high-income country. This may have an effect on both the energy harvest from the diet typifying malnutrition and diarrheal diseases in low-income countries and Western lifestyle diseases in high-income countries.