Immunoglobulin A is the dominant antibody isotype found in mucosal secretions and enforces host-microbiota symbiosis in mice, yet selective IgA-deficiency (sIgAd) in humans is often described as ...asymptomatic. Here, we determined the effects of IgA deficiency on human gut microbiota composition and evaluated the possibility that mucosal secretion of IgM can compensate for a lack of secretory IgA. We used 16S rRNA gene sequencing and bacterial cell sorting to evaluate gut microbiota composition and taxa-specific antibody coating of the gut microbiota in 15 sIgAd subjects and matched controls. Despite the secretion of compensatory IgM into the gut lumen, sIgAd subjects displayed an altered gut microbiota composition as compared to healthy controls. These alterations were characterized by a trend towards decreased overall microbial diversity as well as significant shifts in the relative abundances of specific microbial taxa. While secretory IgA in healthy controls targeted a defined subset of the microbiota via high-level coating, compensatory IgM in sIgAd subjects showed less specificity than IgA and bound a broader subset of the microbiota. We conclude that IgA plays a critical and non-redundant role in controlling gut microbiota composition in humans and that secretory IgA has evolved to maintain a diverse and stable gut microbial community.
A mutual impact of gastrointestinal tract (GIT) and central nervous system (CNS) functions has been recognized since the mid-twentieth century. It is accepted that the so-called gut-brain axis ...provides a two-way homeostatic communication, through immunological, hormonal and neuronal signals. A dysfunction of this axis has been associated with the pathogenesis of some diseases both within and outside the GIT, that have shown an increase in incidence over the last decades. Studies comparing germ-free animals and animals exposed to pathogenic bacterial infections, probiotics or antibiotics suggest the participation of the microbiota in this communication and a role in host defense, regulation of immunity and autoimmune disease appearance. The GIT could represent a vulnerable area through which pathogens influence all aspects of physiology and even induce CNS neuro-inflammation. All those concepts may suggest the modulation of the gut microbiota as an achievable strategy for innovative therapies in complex disorders. Moving from this background, the present review discusses the relationship between intestinal microbiota and CNS and the effects in health and disease. We particularly look at how the commensal gut microbiota influences systemic immune response in some neurological disorders, highlighting its impact on pain and cognition in multiple sclerosis, Guillain-Barrè Syndrome, neurodevelopmental and behavioral disorders and Alzheimer's disease. In this review we discuss recent studies showing that the potential microbiota-gut-brain dialogue is implicated in neurodegenerative diseases. Gaining a better understanding of the relationship between microbiota and CNS could provide an insight on the pathogenesis and therapeutic strategies of these disorders.
It has been suggested that low thyroid hormones levels may be associated with increased mortality in patients with cardiovascular disease.
To evaluate the prognostic role of thyroid function ...deficiency in patients with chronic heart failure (CHF).
We evaluated 338 consecutive outpatients with stable CHF receiving conventional therapy, all of whom underwent a physical examination, electrocardiography and echocardiography. Blood samples were drawn to assess renal function, and Na+, hemoglobin, NT-proBNPs, fT3, fT4 and TSH levels. Patients with hyperthyroidism were excluded.
During the follow-up (15+/-8 months), heart failure progression was observed in 79 patients (including 18 who died of heart failure after hospitalisation and six who underwent transplantation). Univariate regression analysis showed that TSH (p<0.0001), fT3 (p<0.0001), fT4 (p=0.016) and fT3/fT4 (p<0.0001) were associated with heart failure progression but multivariate analysis showed that only TSH considered as a continuous variable (p = 0.001) as well as subclinical hypothyroidism (TSH > 5.5 mUI/l; p=0.014) remained significantly associated with the events.
In CHF patients TSH levels even slightly above normal range are independently associated with a greater likelihood of heart failure progression. This supports the need for prospective studies aimed at clarifying the most appropriate therapeutic approach to sub-clinical hypothyroidism in such patients.
Pathogenic fungi reside in the intestinal microbiota but rarely cause disease. Little is known about the interactions between fungi and the immune system that promote commensalism. Here we ...investigate the role of adaptive immunity in promoting mutual interactions between fungi and host. We find that potentially pathogenic Candida species induce and are targeted by intestinal immunoglobulin A (IgA) responses. Focused studies on Candida albicans reveal that the pathogenic hyphal morphotype, which is specialized for adhesion and invasion, is preferentially targeted and suppressed by intestinal IgA responses. IgA from mice and humans directly targets hyphal-enriched cell-surface adhesins. Although typically required for pathogenesis, C. albicans hyphae are less fit for gut colonization
and we show that immune selection against hyphae improves the competitive fitness of C. albicans. C. albicans exacerbates intestinal colitis
and we demonstrate that hyphae and an IgA-targeted adhesin exacerbate intestinal damage. Finally, using a clinically relevant vaccine to induce an adhesin-specific immune response protects mice from C. albicans-associated damage during colitis. Together, our findings show that adaptive immunity suppresses harmful fungal effectors, with benefits to both C. albicans and its host. Thus, IgA uniquely uncouples colonization from pathogenesis in commensal fungi to promote homeostasis.
During the menopause women may experience increased oxidative stress and decreased antioxidant capacity and, together with the decline of neurosteroids, this represents a risk factor for Alzheimer's ...disease. The aim of the present study was to test a functional food (FPP-ORI, Osato Research Institute, Gifu, Japan) on redox and mitochondrial efficiency in post-menopausal women. The study population consisting of 69 untreated post-menopausal women were given supplements as follows: Group A was given a multivitamin (MV) 1c 2 times a day, and group B was given FPP 4.5 g 2 times a day. Group C consisted of 23 fertile premenopausal women as the control group. The tests carried out on entry, and at 3 and 6 months were erythrocyte redox parameters, plasma oxidated proteins, brain-derived neurotrophic factor (BDNF) and peripheral blood mononuclear cell (PBMC) mitochondria cytochrome c oxidase Vmax activity. Menopausal women showed an increased malondialdehyde (MDA) (p<0.05 vs control) which was normalized by both treatments (p<0.05), but MV failed to do so in the BMI ≥26 subgroup (p<0.05). All other redox enzymes and BDNF were significantly lower in menopausal women and they responded only to FPP (p<0.05). Carbonyl protein level was higher in "BMI ≥ 26" subgroup (p<0.05) and reduced only by FPP (p<0.05). The PBMC cyclooxygenase to citrate synthase activity was reduced (<40%) in the menopausal group (p<0.01) and only FPP caused a significant restoration (p<0.05). Although preliminary, these data confirm the redox and mitochondrial dysfunction occurring in post-menopause and responsive to FPP but very poorly to high dosage antioxidants. This may lead to potential preventive opportunities in menopause-associated neurodegenerative disease.
Methods A retrospective chart review was performed on two patients referred from Hematology clinic for an immunodeficiency evaluation following diagnosis and treatment of thymoma.
A comparative study was carried out between cinnamon oil and clove oil on the oral micro-biota causing dental caries. Cinnamon oil was found to be more effective than clove oil exhibiting broad ...spectrum of antibacterial activity inhibiting all the ten test bacterial species involved in dental caries. Cinnamon oil produced maximum inhibition zone of diameter (IZD) of 24.0 mm against Streptococcus mutans (major causative bacteria of dental plaque) as compared to clove oil (IZD = 13.0mm). This is contrary to the popular belief that clove oil is effective in tooth decay and dental plaque. This study shows the potential of cinnamon oil over clove oil in the treatment of dental caries. (www.actabiomedica.it).
The impacts of individual commensal microbes on immunity and disease can differ dramatically depending on the surrounding microbial context; however, the specific bacterial combinations that dictate ...divergent immunological outcomes remain largely undefined. Here, we characterize an immunostimulatory Allobaculum species from an inflammatory bowel disease patient that exacerbates colitis in gnotobiotic mice. Allobaculum inversely associates with the taxonomically divergent immunostimulatory species Akkermansia muciniphila in human-microbiota-associated mice and human cohorts. Co-colonization with A. muciniphila ameliorates Allobaculum-induced intestinal epithelial cell activation and colitis in mice, whereas Allobaculum blunts the A.muciniphila-specific systemic antibody response and reprograms the immunological milieu in mesenteric lymph nodes by blocking A.muciniphila-induced dendritic cell activation and T cell expansion. These studies thus identify a pairwise reciprocal interaction between human gut bacteria that dictates divergent immunological outcomes. Furthermore, they establish a generalizable framework to define the contextual cues contributing to the “incomplete penetrance” of microbial impacts on human disease.
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•Allobaculum isolates from ulcerative colitis patients exacerbate colitis in mice•Immunostimulatory Allo. sp. are inversely correlated with Akkermansia muciniphila•Co-colonization uniquely alters immune responses elicited by Allo. or A. muc. alone•“Epistatic” interspecies interactions have nonlinear impacts on host immunity
Microbial community context can critically alter commensal-induced immune responses. Here, Rice et al. describe a reciprocal interaction between a novel colitogenic human Allobaculum species and Akkermansia muciniphila that uniquely reprograms the immune responses elicited by either microbe alone, revealing nonlinear impacts of interspecies interactions on host immunity.
An increase in serum levels of pancreatic enzymes is a well-known manifestation of pancreatic disease, especially of inflammatory or neoplastic nature, even if several extrapancreatic diseases can ...equally cause that increase. In addition to this pathological type of hyperenzymemia, different "non-pathological" forms have also been identified, including macroamylasemia, salivary, and mixed salivary and pancreatic hyperamylasemia, in all of which only amylase elevations are seen. Nevertheless, in 1996 a new syndrome characterized by an abnormal, chronic, benign increase in levels of serum amylase, pancreatic isoamylase, lipase and trypsin, asymptomatic and usually discovered incidentally, was described for the first time by Lucio Gullo et al. Hyperamylasemia/hyperlipasemia's observation is nowadays on the increase because general practitioners tend to include more frequently amylase and lipase in routine blood tests and, moreover, because the constant evaluation of this biochemical alteration in the Emergency Unit: for this reason, this syndrome was clearly identified only recently. Therefore, it's characterized by serum elevation of all pancreatic enzymes in the absence of underlying diseases; it occurs in either sporadic or familial form and it persists over time with considerable fluctuation in serum enzyme concentrations, including frequent normalizations. Proper diagnosis of this form of hyperenzymemia is important because it reassures the subjects having this anomaly that the syndrome is benign, and because it can prevent multiple and expensive diagnostic tests or useless hospitalizations or therapies.
ImmunoglobulinA (IgA) is the predominant antibody isotype in the gut, where it regulates commensal flora and neutralizes toxins and pathogens. The function of food-specific IgA in the gut is unknown ...but is presumed to protect from food allergy. Specifically, it has been hypothesized that food-specific IgA binds ingested allergens and promotes tolerance by immune exclusion; however, the evidence to support this hypothesis is indirect and mixed. Although it is known that healthy adults have peanut-specific IgA in the gut, it is unclear whether children also have gut peanut-specific IgA. We found in a cohort of non-food-allergic infants (
= 112) that there is detectable stool peanut-specific IgA that is similar to adult quantities of gut peanut-specific IgA. To investigate whether this peanut-specific IgA is associated with peanut tolerance, we examined a separate cohort of atopic children (
= 441) and found that gut peanut-specific IgA does not predict protection from development of future peanut allergy in infants nor does it correlate with concurrent oral tolerance of peanut in older children. We observed higher plasma peanut-specific IgA in those with peanut allergy. Similarly, egg white-specific IgA was detectable in infant stools and did not predict egg tolerance or outgrowth of egg allergy. Bead-based epitope assay analysis of gut peanut-specific IgA revealed similar epitope specificity between children with peanut allergy and those without; however, gut peanut-specific IgA and plasma peanut-specific IgE had different epitope specificities. These findings call into question the presumed protective role of food-specific IgA in food allergy.
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