Influence of the Gut Microbiota on Blood Acute-Phase Proteins

Biomarkers of cardiometabolic complications in survivors of childhood acute lymphoblastic leukemia

Survivors of childhood acute lymphoblastic leukemia (cALL) are at higher risk of developing cardiometabolic complications. We aimed at exploring the associations between biomarkers of inflammation, oxidative stress, endothelial function, endotoxemia and cardiometabolic risk factors. We conducted a cross-sectional analysis in 246 cALL survivors (mean age, 22.1 ± 6.3 years; mean time since diagnosis, 15.5 ± 5.2 years) and evaluated the associations using a series of logistic regressions. Using structural equation models, we also tested if the relationship between endotoxemia and cardiometabolic complications was mediated by the latent (unobserved) variable inflammation inferred from the observed biomarkers CRP, TNF-α and IL-6. High leptin-adiponectin ratio was associated with obesity [adjusted OR = 15.7; 95% CI (6.2–39.7)], insulin resistance [20.6 (5.2–82.1)] and the metabolic syndrome [11.2 (2.6–48.7)]. Higher levels of plasminogen activator inhibitor-1 and tumor necrosis factor-α were associated with obesity [3.37 (1.6–7.1) and 2.34 (1.3–4.2), respectively] whereas high C-reactive protein levels were associated with insulin resistance [3.3 (1.6–6.8)], dyslipidemia [2.6 (1.4–4.9)] and MetS [6.5 (2.4–17.9)]. Our analyses provided evidence for a directional relationship between lipopolysaccharide binding protein, related to metabolic endotoxemia, inflammation and cardiometabolic outcomes. Identification of biomarkers and biological mechanisms could open new avenues for prevention strategies to minimize the long-term sequelae, improve follow-up and optimize the quality of life of this high-risk population.

Effects of Saccharomyces cerevisiae supplementation on growth performance, plasma metabolites and hormones, and rumen fermentation in Holstein calves during pre- and post-weaning periods

This study aimed to evaluate the effects of supplementing Saccharomyces cerevisiae (SC) during the pre- and post-weaning periods on growth, metabolic and hormonal responses, and rumen fermentation in calves. Three-week-old Holstein calves were assigned to either control (n = 12) or SC group (n = 12), the latter of which received 2 × 10⁹  cfu/day of SC. The experiment was conducted over a period of 7 weeks around weaning. Daily gain (DG) in the SC group was higher (p < .05) than that in the control group. In the SC group, plasma glucose, insulin, and growth hormone (GH) concentrations were higher (p < .05) and concentrations of glucagon and insulin-like growth factor 1 (IGF-1) tended to be higher (p < .1) than in the control group. Proportion of rumen propionate and concentration of rumen ammonia nitrogen at 10 weeks of age were greater (p < .05) in the SC group than that in the control group. Supplementation of SC around weaning may improve dietary nutrient and energy availability and increase plasma GH and IGF-1 concentrations. These changes observed in SC-supplemented calves could be closely related to the improvement of DG.

Heightened Levels of Antimicrobial Response Factors in Patients With Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic progressive autoimmune disease leading to considerable disability over time. The disease can be characterized by the presence of multiple autoantibodies in the serum and synovial fluid. Microbial dysbiosis is proposed to play a role in the pathogenesis of RA. Increased systemic bacterial exposure leads to elevated levels of antimicrobial response factors (ARFs) in the circulation. In the present study, we tested whether RA patients have increased levels of ARFs by analyzing the levels of multiple ARFs in serum from RA patients and healthy age and sex-matched controls. The levels of soluble CD14 (sCD14), lysozyme, and CXCL16 were significantly elevated in RA patients compared to healthy controls. Lipopolysaccharide binding protein (LBP) levels remained unchanged in RA patients compared to healthy controls. A positive correlation of LBP with rheumatoid factor (RF) was also found in RA subjects. Interestingly, the levels of anti-endotoxin core antibodies (EndoCAb) IgM, total IgM, EndoCAb IgA, and total IgA were significantly elevated in RA patients compared to healthy controls. No significant changes in the levels of EndoCAb IgG and total IgG were observed in RA patients compared to healthy controls. Furthermore, lysozyme and CXCL16 levels were positively correlated with disease severity among RA subjects. Increases in the levels of several ARFs and their correlations with clinical indices suggest systemic microbial exposure in the RA cohort. Modulation of microbial exposure may play an important role in disease pathogenesis in individuals with RA.

C-Reactive Protein Causes Adult-Onset Obesity Through Chronic Inflammatory Mechanism

Obesity is characterized by low-grade chronic inflammation. As an acute-phase reactant to inflammation and infection, C-reactive protein (CRP) has been found to be the strongest factor associated with obesity. Here we show that chronic elevation of human CRP at baseline level causes the obesity. The obesity phenotype is confirmed by whole-body magnetic resonance imaging (MRI), in which the total fat mass is 6- to 9- fold higher in the CRP rats than the control rats. Univariate linear regression analysis showed different growth rates between the CRP rats and the control rats, and that the difference appears around 11 weeks old, indicating that they developed adult-onset obesity. We also found that chronic elevation of CRP can prime molecular changes broadly in the innate immune system, energy expenditure systems, thyroid hormones, apolipoproteins, and gut flora. Our data established a causal role of CRP elevation in the development of adult-onset obesity.

Blood protein polymorphisms and the gut bacteria: impact of probiotic Lactobacillus acidophilus Narine on Salmonella carriage in sheep

Related to previous reports on correlations between an animal's genotype, its commensal microbiota, and the ability to resist infections, the aim of the current study was to investigate the associations between sheep genotype and 5-methylcytosine (5-mC) DNA methylation patterns, sheep genotype and cell surface hydrophobicity of sheep gut commensal bacteria. In addition, the effect of the probiotic Lactobacillus acidophilus strain INMIA 9602 Er 317/402 (probiotic formulation Narine) on Salmonella carriage in sheep at Armenian farms was also investigated. Allelotypes and genotypes of different pathogen-sensitive sheep breeds from Armenian farms were studied based on genetic markers of blood transferrin, albumin, and ceruloplasmin. Additionally, the differences between the breeds of Mazekh, Balbas, and Mazekh/Balbas hybrids were reported. The relationship between host sheep blood transferrin and albumin polymorphisms and cell surface hydrophobicity/5-mC DNA methylation patterns from the predominant gut commensal bacteria was shown. The Narine probiotic eliminates Salmonella from the sheep gut microbiota. At the same time, no significant changes in the percentage of 5-mC DNA methylation of predominant gut bacteria after probiotic administration were observed. The evaluation of bacterial cell surface hydrophobicity, the most significant factor affecting bacterial adhesion, as well as 5-mC DNA methylation, might be used for specific sheep husbandry/breeding programs. This study suggests that the commercial probiotic Narine could potentially be used to reduce Salmonella carriage in sheep.

First steps towards combining faecal immunochemical testing with the gut microbiome in colorectal cancer screening

Objectives

Many countries use faecal immunochemical testing (FIT) to screen for colorectal cancer. There is increasing evidence that faecal microbiota play a crucial role in colorectal cancer carcinogenesis. We assessed the possibility of measuring faecal microbial features in FIT as potential future biomarkers in colorectal cancer screening.

Methods

Bacterial stability over time and the possibility of bacterial contamination were evaluated using quantitative polymerase chain reaction analysis. Positive FIT samples (n = 200) of an average-risk screening cohort were subsequently analysed for universal 16S, and bacteria. Escherichia coli (E. coli), Fusobacterium nucleatum (F. nucleatum), Bacteroidetes and Faecalibacterium prausnitzii (F. prausnitzii) by qPCR. The results were compared with colonoscopy findings.

Results

Faecal microbiota in FIT were stably measured up to six days for E. coli (p = 0.53), F. nucleatum (p = 0.30), Bacteroidetes (p = 0.05) and F. prausnitzii (p = 0.62). Overall presence of bacterial contamination in FIT controls was low. Total bacterial load (i.e. 16S) was significantly higher in patients with colorectal cancer and high-grade dysplasia (p = 0.006). For the individual bacteria tested, no association was found with colonic lesions.

Conclusions

These results show that the faecal microbial content can be measured in FIT samples and remains stable for six days. Total bacterial load was higher in colorectal cancer and high-grade dysplasia. These results pave the way for further research to determine the potential role of microbiota assessment in FIT screening.

Testing an infection model to explain excess risk of preterm birth with long-term iron supplementation in a malaria endemic area

Background

In view of recent evidence from a randomized trial in Burkina Faso that periconceptional iron supplementation substantially increases risk of spontaneous preterm birth (< 37 weeks) in first pregnancies (adjusted relative risk = 2.22; 95% CI 1.39–3.61), explanation is required to understand potential mechanisms, including progesterone mediated responses, linking long-term iron supplementation, malaria and gestational age.

Methods

The analysis developed a model based on a dual hit inflammatory mechanism arising from simultaneous malaria and gut infections, supported in part by published trial results. This model is developed to understand mechanisms linking iron supplementation, malaria and gestational age. Background literature substantiates synergistic inflammatory effects of these infections where trial data is unavailable. A path modelling exercise assessed direct and indirect paths influencing preterm birth and gestation length.

Results

A dual hit hypothesis incorporates two main pathways for pro-inflammatory mechanisms, which in this model, interact to increase hepcidin expression. Trial data showed preterm birth was positively associated with C-reactive protein (P = 0.0038) an inflammatory biomarker. The malaria pathway upregulates C-reactive protein and serum hepcidin, thereby reducing iron absorption. The enteric pathway results from unabsorbed gut iron, which induces microbiome changes and pathogenic gut infections, initiating pro-inflammatory events with lipopolysaccharide expression. Data from the trial suggest that raised hepcidin concentration is a mediating catalyst, being inversely associated with shorter gestational age at delivery (P = 0.002) and positively with preterm incidence (P = 0.007). A segmented regression model identified a change-point consisting of two segments before and after a sharp rise in hepcidin concentration. This showed a post change hepcidin elevation in women with increasing C-reactive protein values in late gestation (post-change slope 0.55. 95% CI 0.39–0.92, P < 0.001). Path modelling confirmed seasonal malaria effects on preterm birth, with mediation through C-reactive protein and (non-linear) hepcidin induction.

Conclusions

Following long-term iron supplementation, dual inflammatory pathways that mediate hepcidin expression and culminate in progesterone withdrawal may account for the reduction in gestational age observed in first pregnancies in this area of high malaria exposure. If correct, this model strongly suggests that in such areas, effective infection control is required prior to iron supplementation to avoid increasing preterm births.

Trial registration NCT01210040. Registered with Clinicaltrials.gov on 27th September 2010

Review: Proteomic approaches to control lactational parameters in dairy cows

The use of a proteomic approach to investigate changes in the milk proteome is growing and has parralleled the increasing technological developments in proteomics moving from early investigation using a gel-based two-dimensional separation approach to more quantitative method of current focus applying chromatography and mass spectrometry. Proteomic approaches to investigate lactational performance have made substantial findings especially in the alterations in lactation during mastitis. An experimental model of Streptococcus uberis infection of the mammary gland has been used as a means to determine change not only in the milk proteome, but also in the peptidome and in the metabolome caused by the infection. Examination of the peptidome, that is the peptides of less than 25 kDa in molecular weight, demonstrated an increase in small peptides most of which were casein degradation products but also included small bioactive peptides such as mammary-associated serum amyloid A3 (MSAA3). The peptidome has also been shown to differ depending on the causative bacteria of naturally occuring mastitis. The use of a non-gel-based relative quantitative proteomic methodology has revealed major changes in the protein component of milk in mastitis. The S. uberis infection lead to increases in the concentrations of proteins such as cathelicidins, haptoglobin, MSAA3 and decreases milk content of proteins such as xanthine oxidase, butyrophilin and β-1,4-galactosyltransferase. Analysis of all protein change data identified the acute phase, coagulation and complement pathways as well as proteins related to bile acid metabolism as being most modified. Examination of the small molecular weight organic molecules of milk using a metabolomic approach identified an increase in the content in milk during mastitis of bile acids such as taurochenodeoxycholic acid. Notable changes were also found in metabolites responding to infection of the mammary gland. Carbohydrate and nucleic acid metabolites were reduced, whereas lipid and nitrogen containing metabolites were increased. The latter included increases in amino acids along with di and tri peptides, likely to be the result of casein degradation. The use of proteomics and other omic technology is in its infancy in investigation of lactational parameters, but can already provide additional insight into the changes involved in disease and will have further value in physiological and nutritional investigation of lactation.

Evaluation of Acute Phase Proteins in Clinically Healthy Dairy Cows in Perinatal Period and During Lactation

The estimation of acute phase proteins (APP), which are recognized as inflammation markers is a good method for animal health monitoring. Several factors such as obesity, age and sex are also known to modulate APP status. We evaluated the influence of pregnancy and lactation in 65 clinically healthy dairy Holstein-Friesian dairy cows, 2nd÷4th lactation, chosen from 3 different dairy farms located in South West part of Poland. Bovine C-reactive protein (CRP), haptoglobin and fibrinogen were assayed using commercial ELISA kits. The highest values of CRP and haptoglobin were observed in cows during the first month after calving. The highest concentrations of fibrinogen was found in a group of cows prior to expected date of parturition and the level of this protein in blood plasma was decreasing during lactation. The significant differences of analyzed APPs among cows before delivery, during first month after calving and in lactation (1-3 months after delivery) suggested that factors like pregnancy and stage of lactation would have an influence on their concentration.

Acute phase proteins as promising biomarkers: Perspectives and limitations for human and veterinary medicine

Acute phase proteins (APPs) are highly conserved plasma proteins that are increasingly secreted by the liver in response to a variety of injuries, independently of their location and cause. APPs favor the systemic regulation of defense, coagulation, proteolysis, and tissue repair. Various APPs have been applied as general diagnostic parameters for a long time. Through proteomic techniques, more and more APPs have been discovered to be differentially altered. Since they are not consistently explainable by a stereotypic hepatic expression of sets of APPs, most of these results have unfortunately been neglected or attributed to the nonspecificity of the acute phase reaction. Moreover, it appears that various extrahepatic tissues are also able to express APPs. These extrahepatic APPs show focally specific roles in tissue homeostasis and repair and are released primarily into interstitial and distal fluids. Since these focal proteins might leak into the circulatory system, mixtures of hepatic and extrahepatic APP species can be expected in blood. Hence, a selective alteration of parts of APPs might be expected. There are several hints on multiple molecular forms and fragments of tissue-derived APPs. These differences offer the chance for multiple selective determinations. Thus, specific proteoforms might indeed serve as tissue-specific disease indicators.

Antibiotic Treatment Affects Intestinal Permeability and Gut Microbial Composition in Wistar Rats Dependent on Antibiotic Class

Antibiotics are frequently administered orally to treat bacterial infections not necessarily related to the gastrointestinal system. This has adverse effects on the commensal gut microbial community, as it disrupts the intricate balance between specific bacterial groups within this ecosystem, potentially leading to dysbiosis. We hypothesized that modulation of community composition and function induced by antibiotics affects intestinal integrity depending on the antibiotic administered. To address this a total of 60 Wistar rats (housed in pairs with 6 cages per group) were dosed by oral gavage with either amoxicillin (AMX), cefotaxime (CTX), vancomycin (VAN), metronidazole (MTZ), or water (CON) daily for 10-11 days. Bacterial composition, alpha diversity and caecum short chain fatty acid levels were significantly affected by AMX, CTX and VAN, and varied among antibiotic treatments. A general decrease in diversity and an increase in the relative abundance of Proteobacteria was observed for all three antibiotics. Additionally, the relative abundance of Bifidobacteriaceae was increased in the CTX group and both Lactobacillaceae and Verrucomicrobiaceae were increased in the VAN group compared to the CON group. No changes in microbiota composition or function were observed following MTZ treatment. Intestinal permeability to 4 kDa FITC-dextran decreased after CTX and VAN treatment and increased following MTZ treatment. Plasma haptoglobin levels were increased by both AMX and CTX but no changes in expression of host tight junction genes were found in any treatment group. A strong correlation between the level of caecal succinate, the relative abundance of Clostridiaceae 1 family in the caecum, and the level of acute phase protein haptoglobin in blood plasma was observed. In conclusion, antibiotic-induced changes in microbiota may be linked to alterations in intestinal permeability, although the specific interactions remain to be elucidated as changes in permeability did not always result from major changes in microbiota and vice versa.