Caesarean section and infant formula feeding are associated with an earlier age of onset of multiple sclerosis

Pregnancy complications and autoimmune diseases in women: systematic review and meta-analysis

BACKGROUND

Pregnancy complications might lead to the development of autoimmune diseases in women. This review aims to summarise studies evaluating the association between pregnancy complications and the development of autoimmune diseases in women.

METHODS

Medline, CINAHL, and Cochrane databases were searched up to January 2024. Nineteen pregnancy complications and 15 autoimmune conditions were included. Title, abstract, full-text screening, data extraction, and quality assessment were performed by two reviewers independently. Data were synthesised using narrative and quantitative methods. Results were presented using odds ratios (OR), relative risks (RR), incidence rate ratios (IRR), and 95% confidence intervals (CI).

RESULTS

Thirty studies were included. One study reported composite exposure to pregnancy complications had a risk of any autoimmune disease RR 3.20 (2.90-3.51) compared to women without pregnancy complications. Women with hyperemesis gravidarum had a higher risk of developing coeliac disease (n = 1) IRR 1.98 (1.27-2.94), Crohn's disease (n = 1) IRR 1.61 (1.25-2.04), psoriasis (n = 1) IRR 1.33 (1.01-1.71), and rheumatoid arthritis (n = 2) IRR 1.35 (1.09-1.64). Miscarriage associated with subsequent diagnosis of Sjogren syndrome (n = 2) IRR 1.33 (1.06-2.81) and rheumatoid arthritis (n = 4) OR 1.11 (1.04-1.20). Gestational hypertension/preeclampsia was linked with the development of systemic sclerosis (n = 2) IRR 2.60 (1.10-4.60) and T1DM (n = 2) IRR 2.37 (2.09-2.68). Stillbirth associated with composite autoimmune conditions (n = 2) RR 5.82 (95% CI 4.87-6.81) and aIRR 1.25 (1.12-1.40). Postpartum psychosis was associated with autoimmune thyroid disease (n = 1) aIRR2.26 (1.61-2.90).

CONCLUSIONS

Women with pregnancy complications subsequently had a higher risk of being diagnosed with autoimmune conditions. Whether this is due to pre-existing undiagnosed health conditions or being causally linked to pregnancy complications is not known.

The Translational Future of Stress Neurobiology and Psychosis Vulnerability: A Review of the Evidence

Psychosocial stress is a well-established risk factor for psychosis, yet the neurobiological mechanisms underlying this relationship have yet to be fully elucidated. Much of the research in this field has investigated hypothalamic-pituitary-adrenal (HPA) axis function and immuno-inflammatory processes among individuals with established psychotic disorders. However, as such studies are limited in their ability to provide knowledge that can be used to develop preventative interventions, it is important to shift the focus to individuals with increased vulnerability for psychosis (i.e., high-risk groups). In the present article, we provide an overview of the current methods for identifying individuals at high-risk for psychosis and review the psychosocial stressors that have been most consistently associated with psychosis risk. We then describe a network of interacting physiological systems that are hypothesised to mediate the relationship between psychosocial stress and the manifestation of psychotic illness and critically review evidence that abnormalities within these systems characterise highrisk populations. We found that studies of high-risk groups have yielded highly variable findings, likely due to (i) the heterogeneity both within and across high-risk samples, (ii) the diversity of psychosocial stressors implicated in psychosis, and (iii) that most studies examine single markers of isolated neurobiological systems. We propose that to move the field forward, we require well-designed, largescale translational studies that integrate multi-domain, putative stress-related biomarkers to determine their prognostic value in high-risk samples. We advocate that such investigations are highly warranted, given that psychosocial stress is undoubtedly a relevant risk factor for psychotic disorders.

Feeding the gut microbiome: impact on multiple sclerosis

Multiple sclerosis (MS) is a multifactorial neurological disease characterized by chronic inflammation and immune-driven demyelination of the central nervous system (CNS). The rising number of MS cases in the last decade could be partially attributed to environmental changes, among which the alteration of the gut microbiome driven by novel dietary habits is now of particular interest. The intent of this review is to describe how diet can impact the development and course of MS by feeding the gut microbiome. We discuss the role of nutrition and the gut microbiota in MS disease, describing preclinical studies on experimental autoimmune encephalomyelitis (EAE) and clinical studies on dietary interventions in MS, with particular attention to gut metabolites-immune system interactions. Possible tools that target the gut microbiome in MS, such as the use of probiotics, prebiotics and postbiotics, are analyzed as well. Finally, we discuss the open questions and the prospects of these microbiome-targeted therapies for people with MS and for future research.

Is Early Initiation of Maternal Lactation a Significant Determinant for Continuing Exclusive Breastfeeding up to 6 Months?

BACKGROUND

The World Health Organization (WHO) recommends early initiation of breastfeeding (EIBF) within the first hour after birth. However, certain perinatal factors, namely caesarean section, may prevent this goal from being achieved. The aim of our study was to examine the relationship between EIBF (maternal lactation in the first hours and degree of latching before hospital discharge) and the maintenance of exclusive breastfeeding (MBF) up to the recommended 6 months of age (as advocated by the WHO).

METHODS

This observational, retrospective cohort study included a random sample of all births between 2018 and 2019, characterising the moment of breastfeeding initiation after birth and the infant's level of breast latch (measured by LATCH assessment tool) prior to hospital discharge. Data were collected from electronic medical records and from follow-up health checks of infants up to 6 months postpartum.

RESULTS

We included 342 women and their newborns. EIBF occurred most often after vaginal (p < 0.001) and spontaneous births with spontaneous amniorrhexis (p = 0.002). LATCH score <9 points was associated with a 1.4-fold relative risk of abandoning MBF (95%CI: 1.2-1.7) compared with a score of 9-10 points.

CONCLUSIONS

Although we were unable to find a significant association between EIBF in the first 2 h after birth and MBF at 6 months postpartum, low LATCH scores prior to discharge were associated with low MBF, indicating the importance of reinforcing the education and preparation efforts of mothers in the first days after delivery, prior to the establishment of an infant feeding routine upon returning home.

Involvement of the Intestinal Microbiota in the Appearance of Multiple Sclerosis: Aloe vera and Citrus bergamia as Potential Candidates for Intestinal Health

Multiple sclerosis (MS) is a neurological and inflammatory autoimmune disease of the Central Nervous System in which selective activation of T and B lymphocytes prompts a reaction against myelin, inducing demyelination and axonal loss. Although MS is recognized to be an autoimmune pathology, the specific causes are many; thus, to date, it has been considered a disorder resulting from environmental factors in genetically susceptible individuals. Among the environmental factors hypothetically involved in MS, nutrition seems to be well related, although the role of nutritional factors is still unclear. The gut of mammals is home to a bacterial community of about 2000 species known as the “microbiota”, whose composition changes throughout the life of each individual. There are five bacterial phylas that make up the microbiota in healthy adults: Firmicutes (79.4%), Bacteroidetes (16.9%), Actinobacteria (2.5%), Proteobacteria (1%) and Verrucomicrobia (0.1%). The diversity and abundance of microbial populations justifies a condition known as eubiosis. On the contrary, the state of dysbiosis refers to altered diversity and abundance of the microbiota. Many studies carried out in the last few years have demonstrated that there is a relationship between the intestinal microflora and the progression of multiple sclerosis. This correlation was also demonstrated by the discovery that patients with MS, treated with specific prebiotics and probiotics, have greatly increased bacterial diversity in the intestinal microbiota, which might be otherwise reduced or absent. In particular, natural extracts of Aloe vera and bergamot fruits, rich in polyphenols and with a high percentage of polysaccharides (mostly found in indigestible and fermentable fibers), appear to be potential candidates to re-equilibrate the gut microbiota in MS patients. The present review article aims to assess the pathophysiological mechanisms that reveal the role of the microbiota in the development of MS. In addition, the potential for supplementing patients undergoing early stages of MS with Aloe vera as well as bergamot fibers, on top of conventional drug treatments, is discussed.

Risk Factors from Pregnancy to Adulthood in Multiple Sclerosis Outcome

Multiple sclerosis (MS) is an autoimmune disease characterized by a robust inflammatory response against myelin sheath antigens, which causes astrocyte and microglial activation and demyelination of the central nervous system (CNS). Multiple genetic predispositions and environmental factors are known to influence the immune response in autoimmune diseases, such as MS, and in the experimental autoimmune encephalomyelitis (EAE) model. Although the predisposition to suffer from MS seems to be a multifactorial process, a highly sensitive period is pregnancy due to factors that alter the development and differentiation of the CNS and the immune system, which increases the offspring’s susceptibility to develop MS. In this regard, there is evidence that thyroid hormone deficiency during gestation, such as hypothyroidism or hypothyroxinemia, may increase susceptibility to autoimmune diseases such as MS. In this review, we discuss the relevance of the gestational period for the development of MS in adulthood.

Exposure to breastfeeding and risk of developing multiple sclerosis

BACKGROUND

Early-life factors are reported to modulate the risk of developing multiple sclerosis (MS) among adults. The association between exposure to breastfeeding and the risk of MS is debated. We aimed to disclose whether past exposure to breastfeeding and its duration are associated with the risk of developing MS.

METHODS

We used a cohort design linking prospectively collected information on breastfeeding from the Cohort of Norway community-based surveys on health status (CONOR) with the Norwegian MS Registry and the population-based Medical Birth Registry of Norway that includes information on all births in Norway since 1967. MS clinical onset was collected throughout 2016. A total of 95 891 offspring born between 1922 and 1986 to mothers participating in CONOR were included. We identified 215 offspring within this cohort who developed adult-onset MS. Associations between breastfeeding and MS risk were estimated as hazard ratios using Cox proportional hazard models adjusting for maternal factors including education.

RESULTS

We found no association between having been breastfed for ≥4 months and MS risk, also after adjusting for various maternal factors (hazard ratio = 0.90; 95% confidence interval 0.68-1.19). The estimates did not change for different durations of breastfeeding. The results were similar when adjusting for other perinatal factors.

CONCLUSION

Our study could not confirm previous findings of an association between breastfeeding and risk of MS. Breastfeeding information was less likely to be biased by knowledge of disease compared with case-control studies.

Nutritional and ecological perspectives of the interrelationships between diet and the gut microbiome in multiple sclerosis: Insights from marmosets

Studies in experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis, have shown potential links between diet components, microbiome composition, and modulation of immune responses. In this review, we reanalyze and discuss findings in an outbred marmoset EAE model in which a yogurt-based dietary supplement decreased disease frequency and severity. We show that although diet has detectable effects on the fecal microbiome, microbiome changes are more strongly associated with the EAE development. Using an ecological framework, we further show that the dominant factors influencing the gut microbiota were marmoset sibling pair and experimental time point. These findings emphasize challenges in assigning cause-and-effect relationships in studies of diet-microbiome-host interactions and differentiating the diet effects from other environmental, stochastic, and host-related factors. We advocate for animal experiments to be designed to allow causal inferences of the microbiota's role in pathology while considering the complex ecological processes that shape microbial communities.

The Potential Preventive Effect of Pregnancy and Breastfeeding on Multiple Sclerosis

BACKGROUND

Multiple sclerosis (MS) is an inflammatory demyelinating chronic neurological disease that affects the central nervous system of young adults and their quality of life. Several studies have investigated the effects of pregnancy and breastfeeding on MS. However, the evidence regarding the influence of pregnancy and breastfeeding on MS is still accumulating. This review aimed to summarize the current evidence regarding the effects of pregnancy and breastfeeding on MS.

SUMMARY

A systematic electronic literature search of the PubMed and Embase databases was conducted to determine relevant published articles. The eligible studies were summarized and evaluated in tables. Key Messages: The majority of the studies indicated that pregnancy appears to lower the rate of MS relapses, particularly in the third trimester. The evidence regarding the effect of breastfeeding on MS remains inconsistent. Despite reports of negative obstetric outcomes in some pregnant women with MS, pregnancies in women with MS should not be categorized as high-risk pregnancies.

Delivery Modality Affect Neonatal Levels of Inflammation, Stress, and Growth Factors

Introduction: As part of the study CODIBINE, Correlations and Diagnoses for Biomarkers in New-borns, the main objective of the study was to explore neonatal inflammation, stress, neurodevelopment, and growth factors after in-labor and pre-labor cesarean section compared to vaginal delivery. Increasing evidence has shown that birth delivery mode has an impact on imminent and long-term child health. However, the effect of the timing of cesarean section is insufficiently elucidated. The main objective of the study was to explore the effect of different delivery modes, vaginal delivery compared to cesarean section with or without initiation of labor, on the infants. Methods: We designed a retrospective cohort study, including dried blood spot samples from mature (gestational age ≥ 37) newborns delivered in the years 2009-2011. The newborns were divided into three groups after delivery mode: (1) pre-labor cesarean section (n = 714), i.e., cesarean delivery without initiation of labor, (2) in-labor cesarean section (n = 655), i.e., cesarean section after initiation of labor, and (3) vaginal delivery (n = 5,897). We measured infant levels of inflammatory (IL-18, MCP-1, CRP, sTNF RI), stress (HSP-70), growth (EGF, VEGF-A), and neurotrophic factors (BDNF, NT-3, S100B) 2-4 days after birth. Results: The neonatal levels of inflammatory and stress markers were significantly lower, while the levels of growth factors were higher after pre-labor cesarean section compared to vaginal delivery. The biomarker levels were similar after in-labor cesarean section and vaginal delivery. Removing cases with pre-labor rupture of membranes and artificial rupture of membranes in the calculations did not change the results. The levels of neurotrophic factors were unaffected by delivery form. Males had generally higher levels of inflammation and lower levels of growth and neurotrophic factors. Overall, the levels of inflammatory markers increased, and the growth factors decreased with increasing gestational age. Conclusion: The present study of the biomarker levels after birth suggests that the labor process has an important effect on the fetal immune system and level of stress, regardless if the delivery ends with cesarean section or vaginal birth.

Gut-brain communication in demyelinating disorders

Multiple Sclerosis (MS) is an autoimmune demyelinating disorder resulting from the interplay of genetic predisposition and environmental variables, including gut microbiota, diet and life style factors. Here, we first discuss the evidence supporting the effect of early life events, diet and body mass index on the composition of the microbiota, and then review studies on gut dysbiosis conducted in MS patients and in animal models. We address the effect of disease, immunomodulatory therapies, diet and probiotics on enrichment or depletion of gut microbial species. Finally, we discuss the ability of gut bacteria to produce toxins and metabolites which serve as signals for the cross-talk between the gut and the brain.

Does the gut microbiota contribute to the oligodendrocyte progenitor niche?

The past decade has seen a growing number of studies on the relationship between the gut microbiota and the brain. This mini-review will focus on the unexpected findings linking the microbiome to myelination. We first address the temporal correlation between the acquisition of a gut microbiota in the developing organism and developmental myelination. We then review the factors impacting the composition of the child's gut microbiota, ranging from maternal stress to modality of delivery and from breastfeeding and diet composition to antibiotic treatment early in life. We discuss the topic of gut-brain communication with an emphasis on myelination, and propose the concept that gut microbes produce metabolites which may constitute a "metabolic" niche. Distinct bacterial communities may create very different "niches", some permissive and others inhibitory for myelin generation or maintenance. We speculate that this concept of "gut dysbiosis" may also in part explain the reduced myelin content detected in several neurological and psychiatric disorders. We conclude by envisioning intervention with probiotics and prebiotics to favor the formation of a microbial metabolic "niche" favoring myelin production to promote brain health.