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The Role of Genetically Engineered Probiotics for Treatment of Inflammatory Bowel Disease: A Systematic Review.
Zhang, T, Zhang, J, Duan, L
Nutrients. 2023;15(7)
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Plain language summary
Inflammatory bowel disease (IBD), largely classified as Crohn’s disease (CD) or ulcerative colitis (UC), is a chronic intestinal inflammatory disorder mediated by genetic, immune, microbial, and environmental factors. The aim of this study was to summarise the efficacy of different genetically modified probiotics compared to wild-type probiotics in the treatment of IBD in animal models and patients and to investigate the specific effects and main mechanisms involved. This study was a systematic review of forty-five preclinical studies and one clinical study. Results showed a protective effect of genetically modified organisms (gm) probiotics in colitis. Several protective mechanisms have been identified: reduction of the pro- to anti-inflammatory cytokine ratio in colonic tissue and plasma, modulation of the activity of oxidative stress in the colon, improvement of intestinal barrier integrity, modulation of the diversity and composition of gut microbiota, and production of favourable metabolites, including short-chain fatty acids, by beneficial bacteria. Authors concluded that gm probiotics are more effective and safer than wild-type probiotics, to facilitate clinical translation.
Expert Review
Conflicts of interest:
None
Take Home Message:
Conclusions of this review were largely based on mouse models and although treatment using probiotics is generally considered safe in humans, with only minor side-effects (flatulence), practitioners need to be aware that in an IBD population the use of GM formulations might not be completely without risk.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
This paper summarises the efficacy of specific genetically modified (GM) probiotic formulations for Inflammatory Bowel Disease (IBD) when compared to wild type probiotics. The aim was to ascertain what specific effects and mechanisms such probiotics have on IBD symptomatology.
Methods
- A total of 46 published articles were included; 45 mouse experimental models (induced acute or chronic colitis) (n=15-130) and 1 human IBD population clinical trial (n=10)
- The effect of GM probiotics were compared to placebo and wild-type probiotics in trials including preclinical studies, randomised controlled trials and cohort studies
- Animals received probiotics via gastric gavage (105 - 4 x 1012 CFU) for 3-6 weeks
- The human placebo-uncontrolled trial lasted 7 days and patients received 10 GM capsules of L.lactis (1 x 1010 CFU) twice daily.
Results
- GM probiotics that secrete immunoregulatory cytokines such as IL-10 appear to reduce intestinal damage
- The human trial using GM L.lactis resulted in 5 patients who went into complete clinical remission (CDAI, <150) with 3 patients exhibiting a clinical response (decrease in CDAI, >70). with only minor adverse events (flatulence)
- However, human cytokines that promote intestinal barrier function and epithelial restitution were not enhanced with oral administration of probiotics
- Two studies concluded that GM L.lactis and S.boulardii, that secrete atrial natriuretic peptide, might be the most effective options in supporting colitis
- GM L.casei resulted in faster recovery from weight loss in acute colitis models
- Superoxide dismutase (SOD) producing GM L.fermentum increased SOD activity by almost eightfold compared to the wild type
- GM Lact. fermentum furthermore showed a higher survival rate and lower disease activity index (P <0·05) in colitis models
- GM L.lactis improved gut microbial composition and GM S.cerevisiae improved microbial diversity whilst reducing the Firmicutes to Bacteroides ratio
- GM E.coli significantly reduced weight loss, colon shortening plus lower disease activity and histological changes (P < 0.05).
Conclusion
Despite the heterogeneity of the trials, GM probiotics appear to play a notable part in ameliorating IBD symptomatology and disease severity when compared to wild-type probiotics. Human efficacy and potential adverse effects require more in-depth trials to ascertain safety and optimal dosages.
Clinical practice applications:
- Probiotics species used in the trials included S.thermophilus, E.coli, L.lactis, B.ovatus, S.boulardii, L.fermentum, B.longhum, L.casei, L.plantarum, and S.cerevisiae. Wild-types of some of these are already available to use in clinical practice
- Note that oral administration in the human trial showed no significant health outcome, therefore efficacy and safety need to be ascertained on an individual patient level
- Colonisation of beneficial bacteria in the gut of IBD patients might be difficult and any form of supplementation therefore needs to be closely monitored.
Considerations for future research:
- More evidence is needed to demonstrate that GM probiotic formulations result in significantly improved outcomes when compared to wild-types
- Future randomised placebo-controlled trials need to include larger cohorts to determine supplement efficacy
- Longer periods of intervention are needed to confirm efficacy, safety, and tolerance for both Crohn’s Disease and Colitis
- Optimal GM probiotic formulation, doses, and means of application need to be identified.
Abstract
BACKGROUND Many preclinical studies have demonstrated the effectiveness of genetically modified probiotics (gm probiotics) in animal models of inflammatory bowel disease (IBD). OBJECTIVE This systematic review was performed to investigate the role of gm probiotics in treating IBD and to clarify the involved mechanisms. METHODS PubMed, Web of Science, Cochrane Library, and Medline were searched from their inception to 18 September 2022 to identify preclinical and clinical studies exploring the efficacy of gm probiotics in IBD animal models or IBD patients. Two independent researchers extracted data from the included studies, and the data were pooled by the type of study; that is, preclinical or clinical. RESULTS Forty-five preclinical studies were included. In these studies, sodium dextran sulfate and trinitrobenzene sulfonic acid were used to induce colitis. Eleven probiotic species have been genetically modified to produce therapeutic substances, including IL-10, antimicrobial peptides, antioxidant enzymes, and short-chain fatty acids, with potential therapeutic properties against colitis. The results showed generally positive effects of gm probiotics in reducing disease activity and ameliorating intestinal damage in IBD models; however, the efficacy of gm probiotics compared to that of wild-type probiotics in many studies was unclear. The main mechanisms identified include modulation of the diversity and composition of the gut microbiota, production of regulatory metabolites by beneficial bacteria, reduction of the pro- to anti-inflammatory cytokine ratio in colonic tissue and plasma, modulation of oxidative stress activity in the colon, and improvement of intestinal barrier integrity. Moreover, only one clinical trial with 10 patients with Crohn's disease was included, which showed that L. lactis producing IL-10 was safe, and a decrease in disease activity was observed in these patients. CONCLUSIONS Gm probiotics have a certain efficacy in colitis models through several mechanisms. However, given the scarcity of clinical trials, it is important for researchers to pay more attention to gm probiotics that are more effective and safer than wild-type probiotics to facilitate further clinical translation.
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B-vitamins, related vitamers, and metabolites in patients with quiescent inflammatory bowel disease and chronic fatigue treated with high dose oral thiamine.
Bager, P, Hvas, CL, Hansen, MM, Ueland, P, Dahlerup, JF
Molecular medicine (Cambridge, Mass.). 2023;29(1):143
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IBD is characterised by chronic inflammation of the gastrointestinal tract with periodic inactive (quiescent disease) and periodic active inflammation. Chronic fatigue is regarded as elevated fatigue levels with duration of more than 6 months. Malnutrition in patients with IBD is well known and this study assessed changes in B-vitamins and their related metabolites directly after high dose oral thiamine, vitamin B1. 40 adult patients with quiescent IBD and chronic fatigue were randomised compared to a control group of 20 patients without fatigue. In total, 52 females and 8 men took part in the trial. Half of the patients had Crohn’s disease and half had ulcerative colitis. Blood samples were taken and patients answered questionnaires regarding fatigue at each study visit. The researchers found low levels of Flavin mononucleotide (FMN), a biomolecule produced from riboflavin (vitamin B2) in patients with chronic fatigue in comparison to patients without fatigue. The researchers also observed that fatigued IBD patients had a less diverse microbiome with reduced numbers of butyrate-producing bacterial species compared to non-fatigued patients, highlighting the importance of vitamin B1 for the growth of gut bacteria. The oral dose of vitamin B1 administered is unclear and other factors influencing fatigue such as diet, sleep and physical activity were not investigated. The researchers conclude the mechanisms of B-vitamins in IBD in relation to fatigue does require further exploration along with assessing vitamin B2’s effect on IBD fatigue.
Abstract
BACKGROUND High doses of oral thiamine improve clinical fatigue scores in patients with quiescent inflammatory bowel disease (IBD) and chronic fatigue. In this study we analysed plasma samples obtained in a randomised clinical trial and aimed compare levels of vitamins B1, B2, B3 and B6, and their related vitamers and metabolites in patients with IBD, with or without chronic fatigue and with or without effect of high dose oral thiamine for chronic fatigue. METHODS Blood samples from patients with fatigue were drawn prior and after thiamine exposure and only once for patients without fatigue. A wide panel of analysis were done at Bevital AS Lab. RESULTS Concentration of flavin mononucleotide (FMN) was lower in patients with chronic fatigue compared to patients without fatigue (p = 0.02). Patients with chronic fatigue who reported a positive effect on fatigue after 4 weeks of high dose thiamine treatment had a statistically significantly lower level of riboflavin after thiamine treatment (p = 0.01). CONCLUSION FMN and Riboflavin were associated with chronic fatigue in patients with quiescent IBD. Levels of other B vitamins and metabolites were not significantly different between the investigated groups or related to effect of the thiamine intervention. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov study identifier NCT036347359. Registered 15 August 2018, https://clinicaltrials.gov/study/NCT03634735?cond=Inflammatory%20Bowel%20Diseases&intr=Thiamine&rank=1.
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Functional response to a microbial synbiotic in the gastrointestinal system of children: a randomized clinical trial.
Tierney, BT, Versalovic, J, Fasano, A, Petrosino, JF, Chumpitazi, BP, Mayer, EA, Boetes, J, Smits, G, Parkar, SG, Voreades, N, et al
Pediatric research. 2023;93(7):2005-2013
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The composition of the human gut microbiome has been identified as playing a role in regulating bowel movements in children. This includes functional constipation, which is characterised by infrequent bowel movements and associated phenotypes such as stool consistency, pain when defecating and bloating. The aim of this study was to determine the impact of a nine-strain (eight species) synbiotic (a prebiotic and defined microbial consortium) formulation (with the prebiotic comprising mixed-chain length oligosaccharides) on ameliorating constipation. This study was a multicentre, randomised, double-blind, and placebo-controlled with two parallel arms. Ninety-one healthy male/female subjects were recruited and randomly assigned to one of the two arms; treatment or placebo group. Results showed that: - compared to placebo, synbiotic use increased weekly bowel movements (WBMs) in constipated children. - there was an increased abundance of the administered probiotic species (bifidobacteria) in the treatment arm. - baseline microbial richness demonstrated potential as a predictive biomarker for response to intervention. Authors conclude that a synbiotic formulation may increase weekly WBMs in children who have low-frequency WBMs.
Abstract
BACKGROUND Oral microbial therapy has been studied as an intervention for a range of gastrointestinal disorders. Though research suggests that microbial exposure may affect the gastrointestinal system, motility, and host immunity in a pediatric population, data have been inconsistent, with most prior studies being in neither a randomized nor placebo-controlled setting. The aim of this randomized, placebo-controlled study was to evaluate the efficacy of a synbiotic on increasing weekly bowel movements (WBMs) in constipated children. METHODS Sixty-four children (3-17 years of age) were randomized to receive a synbiotic (n = 33) comprising mixed-chain length oligosaccharides and nine microbial strains, or placebo (n = 31) for 84 days. Stool microbiota was analyzed on samples collected at baseline and completion. The primary outcome was a change from baseline of WBMs in the treatment group compared to placebo. RESULTS Treatment increased (p < 0.05) the number of WBMs in children with low baseline WBMs, despite broadly distinctive baseline microbiome signatures. Sequencing revealed that low baseline microbial richness in the treatment group significantly anticipated improvements in constipation (p = 0.00074). CONCLUSIONS These findings suggest the potential for (i) multi-species-synbiotic interventions to improve digestive health in a pediatric population and (ii) bioinformatics-based methods to predict response to microbial interventions in children. IMPACT Synbiotic microbial treatment improved the number of spontaneous weekly bowel movements in children compared to placebo. Intervention induced an increased abundance of bifidobacteria in children, compared to placebo. All administered probiotic species were enriched in the gut microbiome of the intervention group compared to placebo. Baseline microbial richness demonstrated potential as a predictive biomarker for response to intervention.
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Efficacy of a Synbiotic Containing Lactobacillus paracasei DKGF1 and Opuntia humifusa in Elderly Patients with Irritable Bowel Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial.
Oh, JH, Jang, YS, Kang, D, Kim, HS, Kim, EJ, Park, SY, Kim, CH, Min, YW, Chang, DK
Gut and liver. 2023;17(1):100-107
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Irritable bowel syndrome (IBS) affects 1 in 10 people globally and is a common health problem for the elderly. Recent studies have shown that changes in the gut microbiome may play an important part in IBS and there is evidence that using pre and pro biotics have positive effects on IBS. The aim of this randomized, double-blind, placebo-controlled trial was to determine the effects of a new synbiotic formulation (L. paracasei DKGF1 and prebiotics extracted from O. humifusa) on GI symptoms in elderly patients with IBS. 67 participants were randomly divided into 2 groups. For 4 weeks one group took the synbiotic and the other group took a placebo. Symptoms were recorded via questionnaires. The consumption of the synbiotic combination was associated with overall relief of IBS symptoms in elderly patients. In particular, abdominal pain and psychological well-being noticeably improved. In conclusion this synbiotic is effective and safe to use in elderly patients with global IBS symptoms.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The management of IBS in elderly people is more complicated than in younger populations.
- Synbiotic formulations containing both probiotics and prebiotics have reported gastrointestinal health benefits.
- This randomized controlled trial indicated that the synbiotic containing L. paracasei DKGF1 and Optuntia humifusa extracts might be effective and safe for treating IBS symptoms in elderly patients.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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X
B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
This study involved a randomized, double-blind, placebo-controlled trial to investigate the impact of a synbiotic combination, comprising of L. paracasei DKGF1 and prebiotics extracted from Optuntia humifusa, on Irritable Bowel Syndrome (IBS) in elderly patients.
Method
Sixty-seven IBS patients (mean age: 64 years) were randomly assigned to either a synbiotic group (n=33) or a placebo group (n=34) for a 4-week intervention. The synbiotic group received a daily sachet containing one billion colony-forming units of L. paracasei DKGF1, 0.2g of O. humifusa extract and 1.59 grams of maltodextrin, while the placebo group received an identical sachet containing only maltodextrin.
During the study period
- Participants recorded the degree of symptom improvement using a Subject Global Assessment (SGA) scale.
- IBS symptoms, abdominal pain, gas, bloating, and psychological well-being were recorded using a Visual Analogue Scale (VAS).
- Stool form and consistency were assessed using a Bristol Stool Chart (BSC).
Results
The primary findings from the study were as follows:
- There was significant improvement in IBS symptoms as measured by the SGA score, in the synbiotic group versus the placebo group (+50.5% vs +23.5%, p=0.017). The synbiotic group consistently demonstrated improved response rates.
The secondary findings were as follows:
- Participants also reported an improvement in psychological well-being in the synbiotic group (from 1.3 to 1.0) compared to the placebo group (from 3.0 to 2.0) (p=0.003).
- Responders reported a significant improvement in stool form and consistency in the synbiotic group (+85.7%) compared to the placebo group (+22.2%) (p=0.04).
- Among the patients with IBS constipation, patients in the synbiotic group reported a positive response compared to the placebo group (0% and +100%, p=0.029).
- . However, there was no significant improvement among the patients with IBS diarrhoea in the synbiotic group compared to the placebo group (+33.3% and +66.6%,, p=0.52).
Conclusion:
This randomized, double-blind, placebo-controlled trial, reported that the synbiotic combination of L. paracasei DKGF1 and Optuntia humifusa, may be associated with the relief of IBS symptoms in elderly patients, particularly in terms of abdominal pain and psychological well-being.
Clinical practice applications:
- The human microbiota undergoes changes in diversity and variation with age, emphasising the importance of understanding age-specific interventions.
- Managing IBS in the elderly is challenging, and synbiotics, containing both probiotics and prebiotics, have reported gastrointestinal health benefits.
- Most clinical trials have excluded elderly patients, and there has been uncertainty about whether synbiotic use is safe for the elderly.
- This study focused exclusively on elderly patients with IBS, indicating the potential safety and effective use of a synbiotic containing L. paracasei DKGF1 and Optuntia humifusa in improving IBS symptoms.
Considerations for future research:
- Only elderly patients were included in this study, therefore further investigation is needed to explore the effects of synbiotics on participants of different age groups.
- Microbial analysis was not done in this study. It would be useful to include this in future research to gain more insight into the microbiome’s diversity in elderly patients with IBS.
- The study did not quantify food intake or variety which might have impacted the results, therefore future research needs to consider the impact diet has on the microbiome and IBS.
- Since patient reports are subjective, future research should consider involving researchers during patient-reported assessments to enhance the accuracy and reliability of the data.
Abstract
BACKGROUND/AIMS: There is increasing evidence that supplementation with pre- and probiotics appears to have positive effects on irritable bowel syndrome (IBS). The aim of this study was to determine the effects of a new synbiotic formulation on gastrointestinal symptoms in elderly patients with IBS. METHODS Sixty-seven IBS patients aged ≥60 years were randomly assigned to either a placebo group (n=34) or a synbiotic group (n=33). During a 4-week intervention, subjects used a placebo or a synbiotic containing Lactobacillus paracasei DKGF1 and extracts of Opuntia humifusa once a day. Patients were evaluated with the subject global assessment, visual analog scale, and Bristol stool chart. The primary outcome was the overall responder rate and the secondary outcome was the responder rates for abdominal symptom reduction at week 4. RESULTS Overall, responder rates were significantly higher in the synbiotic group (51.5%) than in the placebo group (23.5%) (p=0.017). Abdominal pain (58.8% vs 81.8%) and psychological well-being (26.4% vs 60.6%) were noticeably improved in the synbiotic group (p=0.038 and p=0.004, respectively). However, there were no significant differences in gas and bloating symptoms (p=0.88 and p=0.88, respectively). In patients with constipation-dominant and diarrhea-dominant IBS (n=16), the synbiotic significantly improved abdominal pain and defecation symptoms (responder rates for the placebo vs the synbiotic: 22.2% vs 85.7%, p=0.04). There were no adverse events in either group. CONCLUSIONS The results indicate that this new synbiotic supplement can potentially relieve abdominal symptoms in elderly IBS patients.
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Early life gut microbiota profiles linked to synbiotic formula effects: a randomized clinical trial in European infants.
Lagkouvardos, I, Intze, E, Schaubeck, M, Rooney, JP, Hecht, C, Piloquet, H, Clavel, T
The American journal of clinical nutrition. 2023;117(2):326-339
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Plain language summary
Microbial colonisation of the intestine after birth is a central event that influences infant health with life-long consequences. Although improvement of hygienic conditions reduces infant mortality due to infections, environments with low microbial biomass counteract natural colonisation by commensal microbes. The aim of this study was to assess the effects of a synbiotic intervention formula (IF) on faecal microbiota. This study was a multicentre, randomised, controlled, double-blind intervention trial which enrolled 540 infants. Infants whose parents had chosen not to breastfeed or were not able to breastfeed prior to study inclusion were allocated randomly to 1 of 2 formula groups (n = 230 control formula, n = 230 IF). The infants in the breastfed reference group (n = 80) were mainly fed human milk. Results showed that synbiotic intervention influenced the gut microbiota and milieu parameters during early life to resemble some major characteristics found in breastfed infants (higher relative abundances of bifidobacteria, lower richness, lower faecal pH and butyrate concentrations), and effects depended on the ecosystem profile of the infants. Authors conclude that specific randomised, controlled studies that focus on infants born by Caesarean section and how early nutrition can support the beneficial development of their microbiota are needed.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Infant gut colonisation differs in vaginal versus cesarean section deliveries and between breastfed and infant formula practices.
- Both enriched strain-specific probiotic and standard infant formula were shown to have a marked effect on microbiota colonisation in infants at age 4 months.
- By the age of 2 years, however, there is no significant difference between breastfed and formula fed infants.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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X
B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
This randomised controlled intervention study compared gut health parameters with the use of a synbiotic pre- and probiotic strain enriched infant formula with human milk and standard formula at three intervals over a period of 2 years.
Methods
This was a double-blinded controlled study of 540 infants from France and Belgium. Participants were randomly allocated to 2 formula groups (n = 230 Control Formula (CF), n = 230 Intervention Formula (IF)) and the breastfed reference group (n = 80) as well as delivery mode (Cesarean and vaginal delivery). The synbiotic IF was a standard infant formula enriched with prebiotic GOS (0.02 g/g) and the probiotic strain L. fermentum CECT5716 (at least 1.0 × 106 cfu/g).
Stool analysis was conducted at three time intervals, 4, 12, and 24 months (infant age). Biomarkers included short chain fatty acids, pH, secretory IgA, calprotectin, and various bacterial phyla via microbiota analysis.
Results
- At 4 months, the IF group tested higher for Bifidobacterium spp., and Lactobacillaceae and lower occurrence of Blautia spp., as well as Ruminoccocus gnavus and relatives compared to CF. They also had lower fecal pH and butyrate levels
- Both the formula cohorts had lower SigA and more basic pH values than the human milk cohort, as well as higher prevalence of anaerobes belonging to the bacterial genera Akkermansia, Collinsella, and Faecalibacterium.
- By age 24 months, the IF cohort exhibited increased levels of Akkermansia, Escherichia-Shigella, and R.gnavus. However there were no significant differences between the formula fed and human milk cohort at this time interval.
- The differences observed at 4 months disappeared over time, except for a significantly higher relative abundance of bifidobacteria and Faecalibacterium spp. in IF infants at 12 months compared with CF infants.
Conclusion:
Although prominent differences between the cohorts were observed at 4 months, it appears that by the age of 2 years, there is little observable difference. This is most likely due to gut ecosystem maturation. The paper draws attention to the fact that changes to microbiota following treatment were more pronounced in infants who tested lower in occurrences of Bacteroides spp at age 4 months. Of note is the prevalence of cesarean birth deliveries in this cohort thereby indicating potential improved alternative feeding options when breastfeeding is not possible for these infants.
Clinical practice applications:
- Probiotic L.fermentum and prebiotic galacto-oligosaccharide enriched infant formula appears to the improve infant microbiome, when compared to that of breastfed infants.
- The most receptive infants were those born via cesarean section.
Limitations to consider:
- The sample groups were from France and Belgium, with no indication as to culture, socio-economic, or sex distribution.
- The two infant formula groups were n=230 each with only 80 infants in the breastfed reference group.
- There was no indication of maternal diet practices pre-, during, and post- pregnancy.
- Stool samples were not collected from the infants at baseline visit prior to formula intervention.
Considerations for future research:
- Future studies need to include more diverse cultural and socio-economic cohorts to ascertain the potential influence of parental diet in baseline infant microbiome.
- It is imperative to establish what role solid food choices, generally introduced at 6 months, might have on gut ecosystem maturation.
- It would be useful to have a larger cesarean section birth cohort to compare to vaginal deliveries for more definitive results.
Abstract
BACKGROUND Microbial colonization of the gastrointestinal tract after birth is an essential event that influences infant health with life-long consequences. Therefore, it is important to investigate strategies to positively modulate colonization in early life. OBJECTIVES This randomized, controlled intervention study included 540 infants to investigate the effects of a synbiotic intervention formula (IF) containing Limosilactobacillus fermentum CECT5716 and galacto-oligosaccharides on the fecal microbiome. METHODS The fecal microbiota from infants was analyzed by 16S rRNA amplicon sequencing at 4, 12, and 24 months of age. Metabolites (e.g., short-chain fatty acids) and other milieu parameters (e.g., pH, humidity, and IgA) were also measured in stool samples. RESULTS Microbiota profiles changed with age, with major differences in diversity and composition. Significant effects of the synbiotic IF compared with control formula (CF) were visible at month 4, including higher occurrence of Bifidobacterium spp. and Lactobacillaceae and lower occurrence of Blautia spp., as well as Ruminoccocus gnavus and relatives. This was accompanied by lower fecal pH and concentrations of butyrate. After de novo clustering at 4 months of age, overall phylogenetic profiles of the infants receiving IF were closer to reference profiles of those fed with human milk than infants fed CF. The changes owing to IF were associated with fecal microbiota states characterized by lower occurrence of Bacteroides compared with higher levels of Firmicutes (valid name Bacillota), Proteobacteria (valid name Pseudomonadota), and Bifidobacterium at 4 months of age. These microbiota states were linked to higher prevalence of infants born by Cesarean section. CONCLUSIONS The synbiotic intervention influenced fecal microbiota and milieu parameters at an early age depending on the overall microbiota profiles of the infants, sharing a few similarities with breastfed infants. This trial was registered at clinicaltrials.gov as NCT02221687.
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The role of gut microbiome in inflammatory skin disorders: A systematic review.
Widhiati, S, Purnomosari, D, Wibawa, T, Soebono, H
Dermatology reports. 2022;14(1):9188
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Plain language summary
Gut-skin axis refers to the complex cross-talk between gut bacteria and skin. Although the exact mechanism underlying chronic inflammatory skin conditions is unknown, imbalances in the composition of gut microbes are believed to play a role. Twenty-three studies were included in this systematic review to assess whether gut microbial imbalance may contribute to inflammatory skin conditions such as Psoriasis, Acne Vulgaris, Atopic Dermatitis, and Urticaria. According to this systematic review, immune stimulation, inflammation, and disruption of bacterial composition are common mechanisms in all these skin disorders. A western diet and environmental exposures are found to be contributing to the disruption of bacteria and the pathology of these skin disorders. It has been observed that friendly gut bacteria such as Bifidobacterium are reduced in people with inflammatory skin conditions, whereas elevated levels of pathogenic bacteria such as E. coli and Proteobacteria are present in the gut of patients with inflammatory skin conditions. The abundance of anti-inflammatory bacteria such as Akkermansia muciniphila, Faecalibacterium prausnitzii, Clostridium leptum, Lactobacillus, and Bifidobacterium may protect against inflammatory skin conditions. Further robust studies are required to evaluate the pathogenesis behind inflammatory skin conditions as well as the involvement of gut bacteria in the development and progression of the disease. Healthcare professionals can gain a deeper understanding of gut bacteria that contribute to the pathology of inflammatory diseases as well as how clinically using anti-inflammatory bacterial species may improve the condition of individuals suffering from inflammatory skin conditions.
Abstract
The close relationship between the intestine and the skin has been widely stated, seen from gastrointestinal (GI) disorders often accompanied by skin manifestations. Exactly how the gut microbiome is related to skin inflammation and influences the pathophysiology mechanism of skin disorders are still unclear. Many studies have shown a two-way relationship between gut and skin associated with GI health and skin homeostasis and allostasis. This systematic review aimed to explore the associations between the gut microbiome with inflammatory skin disorders, such as acne, psoriasis, atopic dermatitis, and urticaria, and to discover the advanced concept of this relationship. The literature search was limited to any articles published up to December 2020 using PubMed and EBSCOHost. The review followed the PRISMA guidelines for conducting a systematic review. Of the 319 articles screened based on title and abstract, 111 articles underwent full-text screening. Of these, 23 articles met our inclusion criteria, comprising 13 atopic dermatitis (AD), three psoriasis, four acne vulgaris, and four chronic urticaria articles. Acne vulgaris, atopic dermatitis, psoriasis, and chronic urticaria are inflammation skin disorders that were studied recently to ascertain the relationship of these disorders with dysbiosis of the GI microbiome. All acne vulgaris, psoriasis, and chronic urticaria studies stated the association of gut microbiome with skin manifestations. However, the results in atopic dermatitis are still conflicting. Most of the articles agree that Bifidobacterium plays an essential role as anti-inflammation bacteria, and Proteobacteria and Enterobacteria impact inflammation in inflammatory skin disorders.
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The vaginal microbiome and the risk of preterm birth: a systematic review and network meta-analysis.
Gudnadottir, U, Debelius, JW, Du, J, Hugerth, LW, Danielsson, H, Schuppe-Koistinen, I, Fransson, E, Brusselaers, N
Scientific reports. 2022;12(1):7926
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Plain language summary
Preterm birth is a major cause of neonatal mortality and morbidity. Many factors can trigger premature labour onset, including preterm premature rupture of membranes, infections and microbial invasion of the amniotic cavity. The vaginal microbiome is thought to protect from such infections. The aim of this study was to assess the association between the vaginal microbiome and the risk of preterm birth. This study is a systematic review and meta-analysis of 17 cohort studies. The number of pregnancies per study ranged between 38 and 539, with 8 and 107 preterm births. Results show that women with a “low-lactobacilli” vaginal microbiome composition were at higher risk of preterm birth (spontaneous and overall) compared to women with L. crispatus (microbiome) dominant microbiome compositions. Authors conclude that the diversity of the vaginal microbiome seems to play a part in the risk of preterm birth.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The diversity of the vaginal microbiome is reported to play a part in the risk of preterm births.
- Practitioners could consider testing the virginal microbiome for low Lactobacilli or the dominance of Gardnerella and Prevotella and then recommending a probiotic supplement to pregnant patients who have low Lactobacilli vaginal microbiome.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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X
B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
A systematic review and network meta-analysis was conducted to investigate the association between vaginal microbiome and risk of preterm births.
Methodology
- Seventeen longitudinal cohort studies were included. Seven originated from North America, three from Europe, two from South America, three from Asia, and two from Africa. The number of pregnancies per study ranged between 38 and 539, with 8 and 107 preterm births. 16S Sequencing techniques were used to identify the microbial species. Preterm birth was defined as birth before 37 weeks of gestation.
- Microbiome community state types (CSTs) were grouped into five categories based on dominating species: L. crispatus, L. gasseri, L. iners,“low-lactobacilli” and L. jensenii. “Low-lactobacilli” was defined as an increased diversity of anaerobic or mixture of aerobe and facultative anaerobe bacteria (such as Gardnerella and Prevotella) based on the cut-offs and categorization used in the individual studies.
Results
Primary clinical outcomes were:
- Among women who delivered preterm, the pooled proportion with “low-lactobacilli” was 0.41 (95% CI 0.30-0.53) compared to 0.29 (95% CI 0.20-0.38) of women with full-term deliveries.
- The risk of preterm births was higher among women with “low-lactobacilli” compared to L. crispatus (OR 1.69, 95%CI 1.15 -2.49).”Low-lactobacilli” included Garnerella and Provotella, both of which are known to promote inflammatory cytokines and are commonly found in vaginal microbiome just before preterm premature rupture of membranes (PPROM).
Clinical practice applications:
- The diversity of the vaginal microbiome is reported to play an important role in the risk of preterm births.
- Women with low Lactobacilli seem to be at a greater risk of delivering preterm compared to women with L. crispatus dominant microbiome.
- Based on this study, practitioners could therefore consider testing the vaginal microbiome of their patients for low Lactobacilli and/or the dominance of Gardnerella and Prevotella.
- Practitioners may also consider recommending specific probiotic supplementation during pregnancy to increase the dominance of Lactobacilli and L. crispatus vaginal microbiome.
Considerations for future research:
- In the past, researchers have grouped the microbiome into categories based on dominating species, which is not ideal. Therefore, further studies are needed where individual microbiome sequencing data is used to make comparisons.
- Additionally, longitudinal studies are needed with higher sample sizes to investigate the natural changes of the vaginal microbiome during pregnancy and the physiological mechanisms underlying these apparent different risk profiles.
- Furthermore, randomized-controlled trials are needed to establish if pregnant women could benefit from specific probiotic supplementation during pregnancy.
Abstract
Preterm birth is a major cause of neonatal morbidity and mortality worldwide. Increasing evidence links the vaginal microbiome to the risk of spontaneous preterm labour that leads to preterm birth. The aim of this systematic review and network meta-analysis was to investigate the association between the vaginal microbiome, defined as community state types (CSTs, i.e. dominance of specific lactobacilli spp, or not (low-lactobacilli)), and the risk of preterm birth. Systematic review using PubMed, Web of Science, Embase and Cochrane library was performed. Longitudinal studies using culture-independent methods categorizing the vaginal microbiome in at least three different CSTs to assess the risk of preterm birth were included. A (network) meta-analysis was conducted, presenting pooled odds ratios (OR) and 95% confidence intervals (CI); and weighted proportions and 95% CI. All 17 studies were published between 2014 and 2021 and included 38-539 pregnancies and 8-107 preterm births. Women presenting with "low-lactobacilli" vaginal microbiome were at increased risk (OR 1.69, 95% CI 1.15-2.49) for delivering preterm compared to Lactobacillus crispatus dominant women. Our network meta-analysis supports the microbiome being predictive of preterm birth, where low abundance of lactobacilli is associated with the highest risk, and L. crispatus dominance the lowest.
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8.
Adverse pregnancy and birth outcomes associated with Mycoplasma hominis, Ureaplasma urealyticum and Ureaplasma parvum: a systematic review and meta-analysis.
Jonduo, ME, Vallely, LM, Wand, H, Sweeney, EL, Egli-Gany, D, Kaldor, J, Vallely, AJ, Low, N
BMJ open. 2022;12(8):e062990
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Plain language summary
Mycoplasma hominis, Ureaplasma parvum and Ureaplasma urealyticum, referred to together as genital mycoplasmas, commonly colonise the urogenital tract in women, and are often found together. These species do not appear to cause symptoms or harmful effects in non-pregnant women. However, studies have reported that colonisation with a genital mycoplasma has been associated with several adverse pregnancy outcomes. The main objective of this study was to investigate the associations between M. hominis, U. urealyticum and/or U. parvum and the risk of pre-term birth, alone and in combination with bacterial vaginosis (BV). This study is a systematic review and meta-analysis of fifty-seven studies. Results show that genital mycoplasmas are associated with several different adverse pregnancy outcomes in univariable analysis only. Authors conclude that since only six of the fifty-seven studies reported multivariable analysis, the current available literature does not allow conclusions about the role of mycoplasmas in adverse pregnancy and birth outcomes, alone or with coexisting BV.
Abstract
OBJECTIVES Mycoplasma hominis, Ureaplasma urealyticum and Ureaplasma parvum (genital mycoplasmas) commonly colonise the urogenital tract in pregnant women. This systematic review aims to investigate their role in adverse pregnancy and birth outcomes, alone or in combination with bacterial vaginosis (BV). METHODS We searched Embase, Medline and CINAHL databases from January 1971 to February 2021. Eligible studies tested for any of the three genital mycoplasmas during pregnancy and reported on the primary outcome, preterm birth (PTB) and/or secondary outcomes low birth weight (LBW), premature rupture of membranes (PROM), spontaneous abortion (SA) and/or perinatal or neonatal death (PND).Two reviewers independently screened titles and abstracts, read potentially eligible full texts and extracted data. Two reviewers independently assessed risks of bias using published checklists. Random effects meta-analysis was used to estimate summary ORs (with 95% CIs and prediction intervals). Multivariable and stratified analyses were synthesised descriptively. RESULTS Of 57/1194 included studies, 39 were from high-income countries. In meta-analysis of unadjusted ORs, M. hominis was associated with PTB (OR 1.87, 95% CI 1.49 to 2.34), PROM, LBW and PND but not SA. U. urealyticum was associated with PTB (OR 1.84, 95% CI 1.34 to 2.55), PROM, LBW, SA and PND. U. parvum was associated with PTB (1.60, 95% CI 1.12 to 2.30), PROM and SA. Nine of 57 studies reported any multivariable analysis. In two studies, analyses stratified by BV status showed that M. hominis and U. parvum were more strongly associated with PTB in the presence than in the absence of BV. The most frequent source of bias was a failure to control for confounding. CONCLUSIONS The currently available literature does not allow conclusions about the role of mycoplasmas in adverse pregnancy and birth outcomes, alone or with coexisting BV. Future studies that consider genital mycoplasmas in the context of the vaginal microbiome are needed. PROSPERO REGISTRATION NUMBER CRD42016050962.
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Interaction of cervical microbiome with epigenome of epithelial cells: Significance of inflammation to primary healthcare.
Holubekova, V, Kolkova, Z, Kasubova, I, Samec, M, Mazurakova, A, Koklesova, L, Kubatka, P, Rokos, T, Kozubik, E, Biringer, K, et al
Biomolecular concepts. 2022;13(1):61-80
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A female health is one medical area of the framework strategies in predictive, preventive, and personalized (3P) medicine. Cervical cancer is preventable and successfully treatable at early stages that makes the disease as an ideal candidate applicable in the context of 3P medicine. The aim of this study was to examine the interaction of the cervical microbiome with epithelial cells in relation to inflammation, and to assess direct evidence of epigenetic changes related to the cervical microbiome. This study is a systematic review of publications in the field of cervical cancer research. This review shows that: - cervical cancer screening in future integration of precision cancer prevention regimes should match an individual’s risk of cancer in context with genomic and environmental factors. - identification of microbiome population might be one of the key aspects of precision medicine in the future. Microbial composition may early identify the potential risk of precancerous lesion formation or permanent bacterial vaginosis. - the composition of the microbiome can be influenced by dietary composition, which will also affect the epigenetic background of the microbiome. However, food forms the microbiome through epigenetic mechanisms, and it is thus necessary to clarify how cancer risk is increased due to food-related microbially produced metabolites. - an examination of the metabolites during inflammation of the cervical epithelium and bacterial vaginosis may improve the precise identification of inflammatory-induced biomarkers that could aid in the precision medicine in prediction of the risk of cervical dysplasia development. - cancer-associated inflammation pathways can be influenced by phytochemicals with anti-inflammatory effects on immune cells, suppression of proinflammatory transcription factors, cytokines, and chemokines. The biological balance between uncontrolled chronic inflammation and controlled inflammation is essential for cancer prevention, prediction, and prognostication. Authors conclude that their review highlighted the pivotal contribution of cervical microbiome, epigenetic changes, and inflammation to the formation of cervical intraepithelial lesion and progression to cervical cancer.
Abstract
One pillar of the predictive, preventive, and personalized medicine framework strategies is the female health. The evaluation of women's lifestyle and dietary habits in context with genetic and modifiable risk factors may reflect the prevention of cervical cancer before the occurrence of clinical symptoms and prediction of cervical lesion behavior. The main aim of this review is to analyze publications in the field of precision medicine that allow the use of research knowledge of cervical microbiome, epigenetic modifications, and inflammation in potential application in clinical practice. Personalized approach in evaluating patient's risk of future development of cervical abnormality should consider the biomarkers of the local microenvironment characterized by the microbial composition, epigenetic pattern of cervical epithelium, and presence of chronic inflammation. Novel sequencing techniques enable a more detailed characterization of actual state in cervical epithelium. Better understanding of all changes in multiomics level enables a better assessment of disease prognosis and selects the eligible targeted therapy in personalized medicine. Restoring of healthy vaginal microflora and reversing the outbreak of cervical abnormality can be also achieved by dietary habits as well as uptake of prebiotics, probiotics, synbiotics, microbial transplantation, and others.
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A Deep Look at the Vaginal Environment During Pregnancy and Puerperium.
Severgnini, M, Morselli, S, Camboni, T, Ceccarani, C, Laghi, L, Zagonari, S, Patuelli, G, Pedna, MF, Sambri, V, Foschi, C, et al
Frontiers in cellular and infection microbiology. 2022;12:838405
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In healthy reproductive-aged women, the vaginal microbiome is generally dominated by members of the Lactobacillus genus. Lactobacilli promote the maintenance of the vaginal health, preventing the colonization and growth of adverse microorganisms through various mechanisms. The composition of the vaginal bacterial communities and related metabolites play a crucial role in maternal-foetal health. The aim of this study was to deepen the characteristics of the vaginal environment in a cohort of Caucasian women with a normal pregnancy throughout their different gestational ages (i.e., first, second, third trimester) and puerperium. This study is a prospective study of sixty-three Caucasian pregnant women. Participants were enrolled and sampled during all gestational ages; for 30 of them, clinical and microbiological data were also available for the puerperium. Additionally, 9 women who had a spontaneous miscarriage at the first trimester of pregnancy (gestational age: 11-13 weeks) during the study were included. Results show that: - irrespective of the period and type of pregnancy, bacterial vaginosis cases were characterised by a dramatic reduction of Lactobacillus and an increase of anaerobic bacteria. - the vaginal microbiome becomes more stable throughout the entire pregnancy, being less diverse and mainly dominated by lactobacilli. - women receiving an intrapartum antibiotic prophylaxis for Group B Streptococcus were characterized by a vaginal abundance of Prevotella compared to untreated women. - at the puerperium, a significantly lower content of Lactobacillus and higher levels of Gardnerella, Prevotella, Atopobium, and Streptococcus were observed. Authors conclude that their findings may help implement ‘prognostic’ criteria (e.g., evaluation of the risk of spontaneous miscarriage based on the microbiome/metabolome profiles), as well as strategies for the prevention of early pregnancy loss, based on the ‘manipulation’ of the vaginal bacterial inhabitants.
Abstract
A deep comprehension of the vaginal ecosystem may hold promise for unraveling the pathophysiology of pregnancy and may provide novel biomarkers to identify subjects at risk of maternal-fetal complications. In this prospective study, we assessed the characteristics of the vaginal environment in a cohort of pregnant women throughout their different gestational ages and puerperium. Both the vaginal bacterial composition and the vaginal metabolic profiles were analyzed. A total of 63 Caucasian women with a successful pregnancy and 9 subjects who had a first trimester miscarriage were enrolled. For the study, obstetric examinations were scheduled along the three trimester phases (9-13, 20-24, 32-34 gestation weeks) and puerperium (40-55 days after delivery). Two vaginal swabs were collected at each time point, to assess the vaginal microbiome profiling (by Nugent score and 16S rRNA gene sequencing) and the vaginal metabolic composition (1H-NMR spectroscopy). During pregnancy, the vaginal microbiome underwent marked changes, with a significant decrease in overall diversity, and increased stability. Over time, we found a significant increase of Lactobacillus and a decrease of several genera related to bacterial vaginosis (BV), such as Prevotella, Atopobium and Sneathia. It is worth noting that the levels of Bifidobacterium spp. tended to decrease at the end of pregnancy. At the puerperium, a significantly lower content of Lactobacillus and higher levels of Gardnerella, Prevotella, Atopobium, and Streptococcus were observed. Women receiving an intrapartum antibiotic prophylaxis for Group B Streptococcus (GBS) were characterized by a vaginal abundance of Prevotella compared to untreated women. Analysis of bacterial relative abundances highlighted an increased abundance of Fusobacterium in women suffering a first trimester abortion, at all taxonomic levels. Lactobacillus abundance was strongly correlated with higher levels of lactate, sarcosine, and many amino acids (i.e., isoleucine, leucine, phenylalanine, valine, threonine, tryptophan). Conversely, BV-associated genera, such as Gardnerella, Atopobium, and Sneathia, were related to amines (e.g., putrescine, methylamine), formate, acetate, alcohols, and short-chain fatty-acids (i.e., butyrate, propionate).