Bovine lactoferrin inhibits SARS-CoV-2 and SARS-CoV-1 by targeting the RdRp complex and alleviates viral infection in the hamster model.

Breast milk has been found to inhibit coronavirus infection, while the key components and mechanisms are unknown. We aimed to determine the components that contribute to the antiviral effects of breastmilk and explore their potential mechanism. Lactoferrin (Lf) and milk fat globule membrane inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related coronavirus GX_P2V and transcription- and replication-competent SARS-CoV-2 virus-like particles in vitro and block viral entry into cells. We confirmed that bovine Lf (bLf) blocked the binding between human angiotensin-converting enzyme 2 and SARS-CoV-2 spike protein by combining receptor-binding domain (RBD). Importantly, bLf inhibited RNA-dependent RNA polymerase (RdRp) activity of both SARS-CoV-2 and SARS-CoV in vitro in the nanomolar range. So far, no biological macromolecules have been reported to inhibit coronavirus RdRp. Our result indicated that bLf plays a major role in inhibiting viral replication. bLf treatment reduced viral load in lungs and tracheae and alleviated pathological damage. Our study provides evidence that bLf prevents SARS-CoV-2 infection by combining SARS-CoV-2 spike protein RBD and inhibiting coronaviruses' RdRp activity, and may be a promising candidate for the treatment of coronavirus disease 2019.

Congenitally underdeveloped intestine drives autism-related gut microbiota and behavior.

Autism spectrum disorder (ASD) is a neurological and developmental disorder accompanied by gut dysbiosis and gastrointestinal symptoms in most cases. However, the development of the autism-related gut microbiota and its relationship with intestinal dysfunction in ASD remain unclear. Using a valproic acid (VPA)-induced ASD mouse model, we showed a congenitally immature intestine of VPA-exposed mice accompanied by prominent oxidative stress and inflammation. Of note, the gut microbiota composition of VPA-exposed mice resembled that of control mice within 24 h after birth; however, their gut microbiota compositions differed on postnatal days 7 and 21. Oral administration of superoxide dismutase (SOD) to attenuate intestinal oxidative stress either before weaning or during juvenile restored the autism-associated gut microbiota, leading to the amelioration of autism-related behaviors. These findings collectively suggest the congenitally underdeveloped intestine as an early driving force shaping the autism-associated gut microbiota and host neurodevelopment through enhancing oxidative stress.

Gastro-Intestinal Digested Bovine Milk Osteopontin Modulates Gut Barrier Biomarkers In Vitro.

SCOPE: Osteopontin (OPN) is a multifunctional protein naturally present in mammals' milk, associated with immune homeostasis and intestinal maturation. This study aims to investigate the protein digestion pattern and the cellular bioactivity of bovine milk OPN digesta in vitro. METHODS AND RESULTS: A modified INFOGEST static in vitro infant digestion protocol and a Caco-2/HT-29 co-culture cell model are employed to evaluate the digestion properties and the anti-inflammatory effects of OPN. OPN is resistant to gastric hydrolysis but degraded into large peptides during intestinal digestion. Its 10 kDa digesta permeate with predicted extensive bioactivities protects the co-culture cell model from the inflammation-induced dysfunction by dose-dependently recovering the expression of occludin, claudin-3, and ZO-1. Low dosage of OPN significantly decreases the production of IL-8 and IL-6, and downregulates the mRNA and protein expression of MyD88, NF-κB p65, and IκB-α, whereas a high dose evokes a mild pro-inflammatory response. Interestingly, anti-inflammatory effect of OPN digesta is stronger than lactoferrin and whey protein concentrate counterparts. CONCLUSION: The findings demonstrate that the bioactive peptides released from in vitro infant gastrointestinal digestion of bovine milk OPN alleviates intestinal epithelial cell inflammation by inhibiting NF-κB pathway activation and potentiates the barrier function of the intestinal epithelium.

Alterations of milk oligosaccharides in mothers with gestational diabetes mellitus impede colonization of beneficial bacteria and development of RORγt+ Treg cell-mediated immune tolerance in neonates.

Gestational diabetes mellitus (GDM) is an increasing public health concern that significantly increases the risk of early childhood allergic diseases. Altered maternal milk glycobiome may strongly affect gut microbiota and enteric-specific Treg cell-mediated development of immune tolerance in GDM infants. In this study, we found that, compared with healthy Chinese mothers, mothers with GDM had significantly lower levels of total and specific human milk oligosaccharides (HMOs) in their colostrum that subsequently increased with extension of lactation. This alteration in HMO profiles significantly delayed colonization of Lactobacillus and Bifidobacterium spp. in their breast-fed infants, resulting in a distinct gut microbial structure and metabolome. Further experiments in GDM mouse models indicated that decreased contents of milk oligosaccharides, mainly 3'-sialyllactose (3'-SL), in GDM maternal mice reduced colonization of bacteria, such as L. reuteri and L. johnsonii, in the neonatal gut, which impeded development of RORγt+ regulatory T (Treg) cell-mediated immune tolerance. Treatment of GDM neonates with 3'-SL, Lactobacillus reuteri (L. reuteri) and L. johnsonii promoted the proliferation of enteric Treg cells and expression of transcription factor RORγt, which may have contributed to compromising ovalbumin (OVA)-induced allergic responses. In vitro experiments showed that 3'-SL, metabolites of L. johnsonii, and lysates of L. reuteri stimulated differentiation of mouse RORγt+ Treg cells through multiple regulatory effects on Toll-like receptor, MAPK, p53, and NOD-like receptor signaling pathways. This study provides new ideas for the development of gut microbiota and immune tolerance in GDM newborns.

Curated and harmonized gut microbiome 16S rRNA amplicon data from dietary fiber intervention studies in humans.

Next generation amplicon sequencing has created a plethora of data from human microbiomes. The accessibility to this scientific data and its corresponding metadata is important for its reuse, to allow for new discoveries, verification of published results, and serving as path for reproducibility. Dietary fiber consumption has been associated with a variety of health benefits that are thought to be mediated by gut microbiota. To enable direct comparisons of the response of the gut microbiome to fiber, we obtained 16S rRNA sequencing data and its corresponding metadata from 11 fiber intervention studies for a total of 2,368 samples. We provide curated and pre-processed genetic data and common metadata for comparison across the different studies.

Human milk oligosaccharides and infant gut microbiota: Molecular structures, utilization strategies and immune function.

Human milk oligosaccharides (HMOs) are a unique class of non-digestible carbohydrates present in the mother milk, which play a key role in the development of infant gut microbiota, epithelial barrier and immune function. The deficiency of HMOs in the bovine milk-based infant formula has been widely recognized as a major culprit for the much higher incidence of immune disorders of formula-fed infants. This report was to give an up-to-date review on the structure characteristics of HMOs and the possible mechanisms, and strategies for their cellular uptake, and metabolism by the gut bacteria and the associated effects on the infant gut microbiome, and immune function. Most previous studies have been carried out in animals or in vitro model systems on the utilization strategies for HMOs in infant bacteria and their roles in infant microbiome, and gut immune function. A few HMO molecules have been synthesized artificially and applied in infant formulas.

In Vitro Infant Fecal Fermentation Characteristics of Human Milk Oligosaccharides Were Controlled by Initial Microbiota Composition More than Chemical Structure.

SCOPE: Human milk oligosaccharides (HMOs), multifunctional glycans naturally present in human milk, are known to contribute to the infant's microbiota and immune system development. However, the molecular specificity of HMOs on microbiota and associated fermentation is not yet fully understood, and is important for the development of infant formula optimum functionality. METHODS AND RESULTS: In vitro fermentation is carried out on structurally different HMOs with infant fecal inocula dominated by Bifidobacterium longum, Bifidobacterium breve, and Bacteroides. The gas, metabolite (SCFA, lactate, and succinate) profiles, and microbiota responses differ between individual microbiota inocula patterns regardless of HMO structure. In terms of HMO pairs with same sugar composition but different glycosidic bonds, gas and metabolite profiles are similar with the B. longum- and B. breve-dominated inocula. However, large individual variations are observed with the Bacteroides-dominated inocula. The microbial communities at the end of fermentation are closely related to the initial microbiota composition. CONCLUSION: The findings demonstrate that short-term in vitro fermentation outcomes largely depend on the initial gut microbiota composition more than the impact of HMO molecular specificity. These results advance the current understanding for the design of personalized infant nutritional solutions and therapies in future.

In vitro fermentation of human milk oligosaccharides by individual Bifidobacterium longum-dominant infant fecal inocula.

This study investigated the fermentation characteristics and microbial responses of human milk oligosaccharides (HMOs) by individual Bifidobacterium longum-dominant infant fecal microbiota. Fucosylated neutral HMOs (2'-fucosyllactose, 2'-FL; 3-fucosyllactose, 3-FL), sialylated HMOs (3'-sialyllactose, 3'-SL; 6'-sialyllactose, 6'-SL), and non-fucosylated neutral HMOs (Lacto-N-tetraose, LNT; Lacto-N-neotetraose, LNnT) were fermented in vitro, with fructooligosaccharides (FOS) and galactooligosaccharides (GOS) as positive controls. The fermentation rate was not affected by the molecular specificity of HMOs. Acetate (98-104 mM) and lactate (9-19 mM) were the primary metabolites at the end of fermentation. All six HMOs showed the same levels of acetate production, but sialylated HMOs produced significantly less lactate than neutral HMOs. HMOs and GOS could maintain the dominance or increase the relative abundance of Bifidobacterium longum, while FOS remarkably promote Klebsiella pneumoniae with the highest gas production and the least acetate and lactate yield. The findings are supportive to optimize infant nutrition strategies for enhanced functions.

Overview of Breastfeeding Under COVID-19 Pandemic.

During the global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), pregnant and lactating women are at higher risk of infection. The potential of viral intrauterine transmission and vertical transmission by breastfeeding has raised wide concerns. Breastmilk is rich in nutrients that contribute to infant growth and development, and reduce the incidence rate of infant illness and death, as well as inhibit pathogens significantly, and protect infants from infection. Although it is controversial whether mothers infected with COVID-19 should continue to breastfeed, many countries and international organizations have provided recommendations and guidance for breastfeeding. This review presents the risks and benefits of breastfeeding for mothers infected with COVID-19, and the reasons for the absence of SARS-CoV-2 active virus in human milk. In addition, the antiviral mechanisms of nutrients in breastmilk, the levels of SARS-CoV-2 specific antibodies in breastmilk from COVID-19 infected mothers and vaccinated mothers are also summarized and discussed, aiming to provide some support and recommendations for both lactating mothers and infants to better deal with the COVID-19 pandemic.

Xiang Study: an association of breastmilk composition with maternal body mass index and infant growth during the first 3 month of life.

BACKGROUND/OBJECTIVES: This study aimed to establish a mother and child cohort in the Chinese population, and investigate human breastmilk (HBM) composition and its relationship with maternal body mass index (BMI) and infant growth during the first 3 mon of life. SUBJECTS/METHODS: A total of 101 Chinese mother and infant pairs were included in this prospective cohort. Alterations in the milk macronutrients of Chinese mothers at 1 mon (T1), 2 mon (T2), and 3 mon (T3) lactation were analyzed. HBM fatty acid (FA) profiles were measured by gas chromatography (GC), and HBM proteomic profiling was achieved by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). RESULTS: During the first 3 mon of lactation (P < 0.05), significant decreases were determined in the levels of total energy, fat, protein, and osteopontin (OPN), as well as ratios of long-chain saturated FA (including C16:0, C22:0 and C24:0), monounsaturated FA (including C16:1), and n-6 poly unsaturated FA (PUFA) (including C20:3n-6 and C20:4n-6, and n-6/n-3). Conversely, butyrate, C6:0 and n-3 PUFA C18:3n-3 (α-linolenic acid, ALA) were significantly increased during the first 3 mon (P < 0.05). HBM proteomic analyses distinguished compositional protein differences over time (P = 0.001). Personalized mother-infant analyses demonstrated that HBM from high BMI mothers presented increased total energy, fat, protein and OPN, and increased content of n-6 PUFA (including C18:3n-6, C20:3n-6 and n-6/n-3 ratio) as compared with low BMI mothers (P < 0.05). Furthermore, BMI of the mothers positively correlated with the head circumference (HC) of infants as well as the specific n-6 PUFA C20:3n-6 over the 3 time points examined. Infant HC was negatively associated with C18:0. CONCLUSION: This study provides additional evidence to the Chinese HBM database, and further knowledge of FA function. It also helps to establish future maternal strategies that support the healthy growth and development of Chinese infants.

Cell wall permeability of pinto bean cotyledon cells regulate in vitro fecal fermentation and gut microbiota.

Processing induced structural changes of whole foods for the regulation of the colonic fermentation rate and microbiota composition are least understood and often overlooked. In the present study, intact cotyledon cells from pinto beans were isolated as a whole pulse food model and subjected to a series of processing temperatures to modulate the structure, most dominantly the cell wall permeability. The cell wall permeability, observed with the diffusion of fluorescently labeled dextran (FITC-dextran), was increased as a function of the hydrothermal temperature, which is in line with the rise in the in vitro fecal fermentation rate and production of short-chain fatty acids (SCFAs) from the pinto bean cells. Further, the abundance of beneficial microbiota, such as Roseburia, Lachnospiraceae, Bacteroides, and Coprococcus, were significantly higher for cells processed at 100 °C compared to the 60 °C-treated ones. We conclude that cell wall provides an effective barrier for the microbial fermentation of intact cells. With an increase in cell wall permeability, microbes and/or microbial enzymes have easier access to intracellular starch for fermentation, leading to an increase in the production of metabolites and the abundance of beneficial microbes. Thus, desired colonic fermentation profiles can be achieved with the controlled processing of whole foods for enhanced gut health.

In vitro colonic fermentation profiles and microbial responses of propionylated high-amylose maize starch by individual Bacteroides-dominated enterotype inocula.

The concept of "enterotype" has been proposed to differentiate the gut microbiota between individual humans, and different dominant bacteria utilize fiber substrates with different fermentation properties and microbial changes. In this study, we made propionylated high-amylose maize starch and investigated both in vitro fecal fermentation properties and microbial responses by individual Bacteroides-dominated enterotype inocula. Propionyl group substitution of HAMS did not significantly change gas production profiles, suggesting that the gas production during fermentation is independent of propionylation. The final concentration of released propionate significantly increased (10.26-12.60 mM) as a function of propionylation degree, suggesting that the introduced propionyl groups can increase the concentration of short-chain fatty acids (SCFA) during colonic fermentation. At the genus level, Bacteroides was obviously promoted for all donors with the final abundance in the range of 0.1-0.24, indicating that propionylated high-amylose maize starch changed the structure and abundance of microbiota compared to unmodified starch. Besides, the non-metric dimensional scoring (NMDS) plots showed that those changes were related to the initial microbiota composition. The results may offer useful information for the design of personalized food products and relevant therapies at least within Bacteroides-dominated enterotype.

Cell Wall Integrity of Pulse Modulates the in Vitro Fecal Fermentation Rate and Microbiota Composition.

The physical structure of type 1 resistant starch (RS 1) could influence the metabolite production and stimulate the growth of specific bacteria in the human colon. In the present study, we isolated intact cotyledon cells from pinto bean seeds as whole pulse food and RS 1 model and obtained a series of cell wall integrities through controlled enzymolysis. In vitro human fecal fermentation performance and microbiota responses were tested, and we reported that the cell wall integrity controls the in vitro fecal fermentation rate of heat-treated pinto bean cells. The concentration of butyrate produced by pinto bean cell fermentation enhanced with weakened cell wall integrity, and certain beneficial bacterial groups such as Blautia and Roseburia genera were remarkably promoted by pinto bean cells with damaged cell wall integrity. However, the intact cell sample had a shape more similar to microbiota composition with the purified cell wall polysaccharides, rather than the damaged cells.

Altered composition and function of intestinal microbiota in autism spectrum disorders: a systematic review.

At present, the pathophysiology of autism spectrum disorder (ASD) remains unclear. Increasing evidence suggested that gut microbiota plays a critical role in gastrointestinal symptoms and behavioral impairment in ASD patients. The primary aim of this systematic review is to investigate potential evidence for the characteristic dysbiosis of gut microbiota in ASD patients compared with healthy controls (HCs). The MEDLINE, EMBASE, Web of Science and Scopus were systematically searched before March 2018. Human studies that compared the composition of gut microbiota in ASD patients and HCs using culture-independent techniques were included. Independent data extraction and quality assessment of studies were conducted according to PRISMA statement and Newcastle-Ottawa Scale. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was used to infer biological functional changes of the shifted microbiota with the available data in four studies. Sixteen studies with a total sample size of 381 ASD patients and 283 HCs were included in this systematic review. The quality of the studies was evaluated as medium to high. The overall changing of gut bacterial community in terms of ß-diversity was consistently observed in ASD patients compared with HCs. Furthermore, Bifidobacterium, Blautia, Dialister, Prevotella, Veillonella, and Turicibacter were consistently decreased, while Lactobacillus, Bacteroides, Desulfovibrio, and Clostridium were increased in patients with ASD relative to HCs in certain studies. This systematic review demonstrated significant alterations of gut microbiota in ASD patients compared with HCs, strengthen the evidence that dysbiosis of gut microbiota may correlate with behavioral abnormality in ASD patients. However, results of inconsistent changing also existed and further big-sampled well-designed studies are needed. Generally, as a potential mediator of risk factors, the gut microbiota could be a novel target for ASD patients in the future.

[A machine learning model based on initial gut microbiome data for predicting changes of Bifidobacterium after prebiotics consumption].

OBJECTIVE: To investigate the effects of prebiotics supplementation for 9 days on gut microbiota structure and function and establish a machine learning model based on the initial gut microbiota data for predicting the variation of Bifidobacterium after prebiotic intake. METHODS: With a randomized double-blind self-controlled design, 35 healthy volunteers were asked to consume fructo-oligosaccharides (FOS) or galacto-oligosaccharides (GOS) for 9 days (16 g per day). 16S rRNA gene high-throughput sequencing was performed to investigate the changes of gut microbiota after prebiotics intake. PICRUSt was used to infer the differences between the functional modules of the bacterial communities. Random forest model based on the initial gut microbiota data was used to identify the changes in Bifidobacterium after 5 days of prebiotic intake and then to build a continuous index to predict the changes of Bifidobacterium. The data of fecal samples collected after 9 days of GOS intervention were used to validate the model. RESULTS: Fecal samples analysis with QIIME revealed that FOS intervention for 5 days reduced the intestinal flora alpha diversity, which rebounded on day 9; in GOS group, gut microbiota alpha diversity decreased progressively during the intervention. Neither FOS nor GOS supplement caused significant changes in ß diversity of gut microbiota. The area under the curve (AUC) of the prediction model was 89.6%. The continuous index could successfully predict the changes in Bifidobacterium (R=0.45, P=0.01), and the prediction accuracy was verified by the validation model (R=0.62, P=0.01). CONCLUSION: Short-term prebiotics intervention can significantly decrease α-diversity of the intestinal flora. The machine learning model based on initial gut microbiota data can accurately predict the changes in Bifidobacterium, which sheds light on personalized nutrition intervention and precise modulation of the intestinal flora.

Fructooligosaccharide (FOS) and Galactooligosaccharide (GOS) Increase Bifidobacterium but Reduce Butyrate Producing Bacteria with Adverse Glycemic Metabolism in healthy young population.

The gut microbiota has been implicated in glucose intolerance and its progression towards type-2 diabetes mellitus (T2DM). Relevant randomized clinical trial with prebiotic intervention was inadequate. We sought to evaluate the impact of fructooligosaccharides (FOS) and galactooligosaccharides (GOS) on glycemia during oral glucose tolerance test (OGTT) and intestinal microbiota. A randomized double-blind cross-over study was performed with 35 adults treated with FOS and GOS for 14 days (16 g/day). Faeces sampling, OGTT and anthropometric parameters were performed. Short-term intake of high-dose prebiotics had adverse effect on glucose metabolism, as in FOS intervention demonstrated by OGTT (P < 0.001), and in GOS intervention demonstrated by fasting glucose (P < 0.05). A significant increase in the relative abundance of Bifidobacterium was observed both in FOS and GOS group, while the butyrate-producing bacteria like Phascolarctobacterium in FOS group and Ruminococcus in GOS group were decreased. A random forest model using the initial microbiota was developed to predict OGTT levels after prebiotic intervention with relative success (R = 0.726). Our study alerted even though FOS and GOS increased Bifidobacterium, they might have adverse effect on glucose metabolism by reducing butyrate-producing microbes. Individualized prebiotics intervention based on gut microbiome needs to be evaluated in future.

Dysbiosis of Gut Microbiota With Reduced Trimethylamine-N-Oxide Level in Patients With Large-Artery Atherosclerotic Stroke or Transient Ischemic Attack.

BACKGROUND: Gut microbiota has been suggested to play a role in almost all major diseases including cardio- and cerebrovascular diseases. A possible mechanism is the transformation of dietary choline and l-carnitine into trimethylamine by gut bacteria. This metabolite is further oxidized into trimethylamine-N-oxide (TMAO) in liver and promotes atherogenesis. Nevertheless, little is known about gut microbial diversity and blood TMAO levels in stroke patients. METHODS AND RESULTS: We performed a case-control study of patients with large-artery atherosclerotic ischemic stroke and transient ischemic attack. TMAO was determined with liquid chromatography tandem mass spectrometry. Gut microbiome was profiled using Illumina sequencing of the 16S rRNA V4 tag. Within the asymptomatic control group, participants with and without carotid atherosclerotic plaques showed similar levels of TMAO without a significant difference in gut microbiota; however, the gut microbiome of stroke and transient ischemic attack patients was clearly different from that of the asymptomatic group. Stroke and transient ischemic attack patients had more opportunistic pathogens, such as Enterobacter, Megasphaera, Oscillibacter, and Desulfovibrio, and fewer commensal or beneficial genera including Bacteroides, Prevotella, and Faecalibacterium. This dysbiosis was correlated with the severity of the disease. The TMAO level in the stroke and transient ischemic attack patients was significantly lower, rather than higher, than that of the asymptomatic group. CONCLUSIONS: Participants with asymptomatic atherosclerosis did not exhibit an obvious change in gut microbiota and blood TMAO levels; however, stroke and transient ischemic attack patients showed significant dysbiosis of the gut microbiota, and their blood TMAO levels were decreased.

Identification and typing of respiratory adenoviruses in Guangzhou, Southern China using a rapid and simple method.

Human adenoviruses (HAdVs), especially HAdV-B3, -E4 and -B7, are associated with Acute Respiratory Disease in Chinese children, and occasionally in adults. In order to establish and document the profiles of the respiratory adenovirus pathogen among children in Guangzhou, Southern China, a rapid, simple and practical method for identification and typing of respiratory adenoviruses was developed and evaluated. One pair of universal PCR primers was designed according to the conserved region of the hexon gene, which can detect not only HAdV-B3, -E4 and -B7, but also HAdV-B14, -F40 and -F41, with a specific 300bp PCR product. Three pairs of type-specific PCR primers were also designed according to the hypervariable regions of the hexon gene to type HAdV-B3, -E4 and -B7 by three independent PCR reactions, making it easy to optimize the PCR conditions. By using this method, one hundred throat swab specimens collected during Oct 2010 to Dec 2011 and suspected of being positive for adenoviral infection were identified and typed for adenoviruses. Of these samples, fifty-five were adenovirus-positive. The most common HAdV type was HAdV-B3, identified in 92.7% of samples, which is not only consistent with the data reported in 2004-2006, but also consistent with the recent report in Hangzhou, eastern China, indicating that HAdV-B3 has been circulating in Guangzhou, and maybe in eastern China, for many years. The method for the respiratory adenovirus identification and typing we developed is rapid, simple and practical, which has a potential in the real-time surveillance of circulating adenovirus strains and also to provide etiological evidence for the adenovirus-relative disease control and prevention in China.