Plasma lipopolysaccharide-binding protein and colorectal cancer risk: a nested case-control study in the Multiethnic Cohort

Probiotics, gut microbiome, and cardiovascular diseases: An update

Cardiovascular diseases (CVD) are one of the most challenging diseases and many factors have been demonstrated to affect their pathogenesis. One of the major factors that affect CVDs, especially atherosclerosis, is the gut microbiota (GM). Genetics play a key role in linking CVDs with GM, in addition to some environmental factors which can be either beneficial or harmful. The interplay between GM and CVDs is complex due to the numerous mechanisms through which microbial components and their metabolites can influence CVDs. Within this interplay, the immune system plays a major role, mainly based on the immunomodulatory effects of microbial dysbiosis and its resulting metabolites. The resulting modulation of chronic inflammatory processes was found to reduce the severity of CVDs and to maintain cardiovascular health. To better understand the specific roles of GM-related metabolites in this interplay, this review presents an updated perspective on gut metabolites related effects on the cardiovascular system, highlighting the possible benefits of probiotics in therapeutic strategies.

Circulating markers of microbial translocation and host response to bacteria with risk of colorectal cancer: a prospective, nested case-control study in men

BACKGROUND

Gut microbial dysbiosis contributes to colorectal cancer (CRC) pathogenesis, possibly mediated in part by increased intestinal permeability to endotoxin lipopolysaccharide (LPS), microbial translocation, and subsequent endotoxemia and inflammation. However, epidemiologic evidence linking circulating markers of microbial translocation with CRC risk is limited.

METHODS

We conducted a prospective, nested case-control study of 261 incident CRC cases and 261 controls (matched on age and time of blood draw) among 18,159 men with pre-diagnostic blood specimens in the Health Professionals Follow-Up Study (1993-2009). We examined three complementary markers of microbial translocation and host response to bacteria, including LPS-binding protein (LBP), soluble CD14 (sCD14), and endotoxincore antibody (EndoCAb) immunoglobulin M (IgM), with subsequent risk of CRC. Unconditional logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

FINDINGS

Pre-diagnostic circulating levels of sCD14 were associated with a higher risk of incident CRC. Compared to men in the lowest quartile, the multivariable OR was 1.90 (95% CI, 1.13-3.22) for men in the highest quartile (OR _{per standard deviation [SD] increase}, 1.28; 95%CI 1.06-1.53; P_trend = 0.01). This positive association remained similar after adjusting for C-reactive protein, interleukin-6, and soluble tumor necrosis factor receptor-2, and within strata of putative CRC risk factors. We also observed a suggestive inverse association between EndoCAb IgM and risk of CRC (OR _{per SD increase}, 0.84; 95%CI 0.69-1.02; P_trend = 0.09).

INTERPRETATION

Microbial translocation and host response to bacteria, as reflected by sCD14, is associated with risk of incident CRC in men.

FUNDING

US National Institutes of Health.

Associations of the Dietary Inflammatory Index with total adiposity and ectopic fat through the gut microbiota, LPS, and C-reactive protein in the Multiethnic Cohort-Adiposity Phenotype Study

BACKGROUND

Mechanisms linking a proinflammatory diet to obesity remain under investigation. The ability of diet to influence the gut microbiome (GM) in creating chronic low-grade systemic inflammation provides a plausible connection to adiposity.

OBJECTIVES

Assess whether any associations seen between the Energy-Adjusted Dietary Inflammatory Index (E-DII score), total fat mass, visceral adipose tissue (VAT), or liver fat (percentage volume) operated through the GM or microbial related inflammatory factors, in a multiethnic cross-sectional study.

METHODS

In the Multiethnic Cohort-Adiposity Phenotype Study (812 men, 843 women, aged 60-77 y) we tested whether associations between the E-DII and total adiposity, VAT, and liver fat function through the GM, LPS, and high-sensitivity C-reactive protein (hs-CRP). DXA-derived total fat mass, MRI-measured VAT, and MRI-based liver fat were measured. Participants provided stool and fasting blood samples and completed an FFQ. Stool bacterial DNA was amplified and the 16S rRNA gene was sequenced at the V1-V3 region. E-DII score was computed from FFQ data, with a higher E-DII representing a more proinflammatory diet. The associations between E-DII score, GM (10 phyla, 28 genera, α diversity), and adiposity phenotypes were examined using linear regression and mediation analyses, adjusting for confounders.

RESULTS

There were positive total effects (c) between E-DII and total fat mass (c = 0.68; 95% CI: 0.47, 0.90), VAT (c = 4.61; 95% CI: 2.95, 6.27), and liver fat (c = 0.40; 95% CI: 0.27, 0.53). The association between E-DII score and total fat mass was mediated by LPS, Flavonifractor, [Ruminococcus] gnavus group, and Tyzzerella. The association between E-DII score and ectopic fat occurred indirectly through Fusobacteria, Christensenellaceae R-7 group, Coprococcus 2, Escherichia-Shigella, [Eubacterium] xylanophilum group, Flavonifractor, Lachnoclostridium, [Ruminococcus] gnavus group, Tyzzerella, [Ruminococcus] gnavus group (VAT only), and α diversity (liver fat only). There was no significant association between E-DII score and adiposity phenotype through hs-CRP.

CONCLUSIONS

Associations found between E-DII and adiposity phenotypes occurred through the GM and LPS.

Lipopolysaccharide-binding protein as a risk factor for development of infectious and inflammatory postsurgical complications in colorectal cancer paients

Aim of the study

In this pilot study lipopolysaccharide-binding protein (LBP) levels were assessed as a possible risk factor for development of systemic inflammatory response syndrome (SIRS) and infectious and inflammatory complications in colorectal cancer (CRC) patients after surgery.

Material and methods

For LBP determination venous blood was taken 1 hour before the surgery and 72 hours after it. All patients were stratified by the presence or absence of acute bowel obstruction (ABO), SIRS and complications.

Results

36 patients with CRC participated in the study. The LBP level before surgery was 879.8 ± 221.8 ng/ml (interquartile range (IQR) 749.3-1028.8); on the 3^rd day it was 766.5 ± 159.4 ng/ml (IQR 669.5-847.6), which was a statistically significant decrease (p = 0.004). A decrease in LBP level by more than 280 ng/ml increases the probability of SIRS and complications in operated CRC patients (OR 6.6, 95% CI: 1.1-40.9 and OR 12.0, 95% CI: 1.8-80.4, respectively). In patients with ABO in the presence of SIRS, the LBP value decreased more than in those without SIRS (p = 0.046).

Conclusions

This study demonstrated that the LBP level in the operated CRC patients tends to decrease on the 3^rd day after surgery. A bigger decrease in LBP level increases the probability of SIRS and postoperative infectious and inflammatory complications. Therefore, further studies with larger numbers of patients are required.

Influence of the Gut Microbiome, Diet, and Environment on Risk of Colorectal Cancer

Researchers have discovered associations between elements of the intestinal microbiome (including specific microbes, signaling pathways, and microbiota-related metabolites) and risk of colorectal cancer (CRC). However, it is unclear whether changes in the intestinal microbiome contribute to the development of sporadic CRC or result from it. Changes in the intestinal microbiome can mediate or modify the effects of environmental factors on risk of CRC. Factors that affect risk of CRC also affect the intestinal microbiome, including overweight and obesity; physical activity; and dietary intake of fiber, whole grains, and red and processed meat. These factors alter microbiome structure and function, along with the metabolic and immune pathways that mediate CRC development. We review epidemiologic and laboratory evidence for the influence of the microbiome, diet, and environmental factors on CRC incidence and outcomes. Based on these data, features of the intestinal microbiome might be used for CRC screening and modified for chemoprevention and treatment. Integrated prospective studies are urgently needed to investigate these strategies.

Consumption of pomegranate decreases plasma lipopolysaccharide-binding protein levels, a marker of metabolic endotoxemia, in patients with newly diagnosed colorectal cancer: a randomized controlled clinical trial

Gut microbiota dysbiosis alters the intestinal barrier function, increases plasma lipopolysaccharide (LPS) levels, which promotes endotoxemia, and contributes to the onset and development of colorectal cancer (CRC). We report here for the first time the reduction of plasma LPS-binding protein (LBP) levels, a marker of endotoxemia, after pomegranate consumption in newly diagnosed CRC patients.