Significance of Markers of Monocyte Activation (CD163 and sCD14) and Inflammation (IL-6) in Patients Admitted for Alcohol Use Disorder Treatment

Inflammation, oxidative stress and gut microbiome perturbation: A narrative review of mechanisms and treatment of the alcohol hangover

Alcohol is the most widely abused substance in the world, the leading source of mortality in 15-49-year-olds, and a major risk factor for heart disease, liver disease, diabetes, and cancer. Despite this, alcohol is regularly misused in wider society. Consumers of excess alcohol often note a constellation of negative symptoms, known as the alcohol hangover. However, the alcohol hangover is not considered to have long-term clinical significance by clinicians or consumers. We undertook a critical review of the literature to demonstrate the pathophysiological mechanisms of the alcohol hangover. Hereafter, the alcohol hangover is re-defined as a manifestation of sickness behavior secondary to alcohol-induced inflammation, using the Bradford-Hill criteria to demonstrate causation above correlation. Alcohol causes inflammation through oxidative stress and endotoxemia. Alcohol metabolism is oxidative and increased intake causes relative tissue hypoxia and increased free radical generation. Tissue damage ensues through lipid peroxidation and the formation of DNA/protein adducts. Byproducts of alcohol metabolism such as acetaldehyde and congeners, sleep deprivation, and the activation of nonspecific inducible CYP2E1 in alcohol-exposed tissues exacerbate free radical generation. Tissue damage and cell death lead to inflammation, but in the intestine loss of epithelial cells leads to intestinal permeability, allowing the translocation of pathogenic bacteria to the systemic circulation (endotoxemia). This leads to a well-characterized cascade of systemic inflammation, additionally activating toll-like receptor 4 to induce sickness behavior. Considering the evidence, it is suggested that hangover frequency and severity may be predictors of the development of later alcohol-related diseases, meriting formal confirmation in prospective studies. In light of the mechanisms of alcohol-mediated inflammation, research into gut permeability and the gut microbiome may be an exciting future therapeutic avenue to prevent alcohol hangover and other alcohol-related diseases.

Gut-liver axis: Recent concepts in pathophysiology in alcohol-associated liver disease

The growing recognition of the role of the gut microbiome's impact on alcohol-associated diseases, especially in alcohol-associated liver disease, emphasizes the need to understand molecular mechanisms involved in governing organ-organ communication to identify novel avenues to combat alcohol-associated diseases. The gut-liver axis refers to the bidirectional communication and interaction between the gut and the liver. Intestinal microbiota plays a pivotal role in maintaining homeostasis within the gut-liver axis, and this axis plays a significant role in alcohol-associated liver disease. The intricate communication between intestine and liver involves communication between multiple cellular components in each organ that enable them to carry out their physiological functions. In this review, we focus on novel approaches to understanding how chronic alcohol exposure impacts the microbiome and individual cells within the liver and intestine, as well as the impact of ethanol on the molecular machinery required for intraorgan and interorgan communication.

Predominantly Pro-Inflammatory Phenotype with Mixed M1/M2 Polarization of Peripheral Blood Classical Monocytes and Monocyte-Derived Macrophages among Patients with Excessive Ethanol Intake

Excessive alcohol consumption impairs the immune system, induces oxidative stress, and triggers the activation of peripheral blood (PB) monocytes, thereby contributing to alcoholic liver disease (ALD). We analyzed the M1/M2 phenotypes of circulating classical monocytes and macrophage-derived monocytes (MDMs) in excessive alcohol drinkers (EADs). PB samples from 20 EADs and 22 healthy controls were collected for isolation of CD14+ monocytes and short-term culture with LPS/IFNγ, IL4/IL13, or without stimulation. These conditions were also used to polarize MDMs into M1, M2, or M0 phenotypes. Cytokine production was assessed in the blood and culture supernatants. M1/M2-related markers were analyzed using mRNA expression and surface marker detection. Additionally, the miRNA profile of CD14+ monocytes was analyzed. PB samples from EADs exhibited increased levels of pro-inflammatory cytokines. Following short-term culture, unstimulated blood samples from EADs showed higher levels of soluble TNF-α and IL-8, whereas monocytes expressed increased levels of surface TNF-α and elevated mRNA expression of pro-inflammatory cytokines and inducible nitric oxide synthase. MDMs from EADs showed higher levels of TNF-α and CD206 surface markers and increased IL-10 production. LPS/IFNγ induced higher mRNA expression of Nrf2 only in the controls. miRNA analysis revealed a distinctive miRNA profile that is potentially associated with liver carcinogenesis and ALD through inflammation and oxidative stress. This study confirms the predominantly pro-inflammatory profile of PB monocytes among EADs and suggests immune exhaustion features in MDMs.

Fungal plasma biomarkers in patients admitted for inpatient treatment of alcohol use disorder

BACKGROUND

Fungal plasma biomarkers have not been studied in patients with unhealthy alcohol use and no apparent end-stage liver disease.

METHODS

We examined the prevalence of fungal plasma biomarkers, assessed by the presence of anti-Saccharomyces cerevisiae antibodies (ASCA; IgA and IgM), and its disease correlates in patients with alcohol use disorder (AUD). We performed logistic regression analyses to detect the association between clinical and laboratory characteristics and the presence of fungal plasma biomarkers.

RESULTS

We included 395 patients (75.9% male, median age of 49 years, and median body mass index of 25.6) who drank a median of 150 g of alcohol daily and had a median duration of AUD of 20 years. ASCA IgA and IgG were present in 34.4% and 14.9%, respectively, and 9.9% had both ASCA IgA and ASCA IgG. The presence of ASCA IgA was associated with male sex (p < 0.01); values of serum aspartate transferase (AST) (p = 0.02), gamma-glutamyl transferase (GGT) (p < 0.01), alkaline phosphatase (ALP) (p < 0.01), and bilirubin in the highest quartile (p < 0.01); Fibrosis-4 Index (FIB-4) values suggestive of advanced liver fibrosis (p < 0.01); and values of the macrophage activation factors sCD163 (p < 0.01) and sCD14 (p < 0.01), the cytokine IL-6 (p = 0.01), and lipopolysaccharide-binding protein in the highest quartile (p < 0.01). The presence of ASCA IgG was associated with omeprazole use (p = 0.04); values of AST (p = 0.04) and GGT (p = 0.04) in the highest quartile; FIB-4 values suggestive of advanced liver fibrosis (p < 0.01); and values of sCD163 (p < 0.01) in the highest quartile. The variables associated with the presence of both ASCA IgA and IgG were male sex (p = 0.04) and values of GGT (p = 0.04) and sCD163 in the highest quartile (p < 0.01).

CONCLUSIONS

In AUD patients, the presence of fungal biomarkers in plasma was common and associated with FIB-4 values suggestive of advanced liver fibrosis and with markers of liver damage, monocyte activation, and microbial translocation, male gender, and omeprazole use. These findings suggest that the presence of plasma anti-Saccharomyces cerevisiae antibodies could be used as a biomarker for an elevated risk of progressive liver disease in patients with AUD.

Cumulative life-course victimization and inflammation in a U.S. national sample: Comparing intersections based on sexual orientation, gender, race/ethnicity, and education

Violence victimization has been associated with low-grade inflammation. Lesbian, Gay, and Bisexual (LGB) individuals are at greater risk for victimization in childhood and young adulthood compared to heterosexuals. Moreover, the intersection of LGB identity with gender, race/ethnicity, and educational attainment may be differentially associated with victimization rates. However, no previous study has examined the role of cumulative life-course victimization during childhood and young adulthood in the association between 1) LGB identity and low-grade inflammation during the transition to midlife, and 2) intersection of LGB identity with gender, race/ethnicity, and educational attainment and low-grade inflammation during the transition to midlife. We utilized multi-wave data from a national sample of adults entering midlife in the United States- the National Longitudinal Study of Adolescent to Adult Health (Add Health; n = 4573) - and tested four bootstrapped mediation models. Results indicate LGB identity, LGB and White, and LGB and Black identities were indirectly associated with low-grade inflammation during the transition to midlife via higher levels of cumulative life-course victimization. Moreover, among LGB adults, the association between 1) less than college education and 2) some college education, and low-grade inflammation was mediated by cumulative life-course victimization. For LGB females, there was a direct association between identity and low-grade inflammation and this association was mediated by cumulative life-course victimization . Reducing accumulation of victimization could be critical for preventing biological dysregulation and disease onset among LGB individuals, particularly for those with multiple marginalized identities.

C-Reactive Protein (CRP): A Potent Inflammation Biomarker in Psychiatric Disorders

An increasing number of studies have investigated the role of inflammation in psychiatric disorders, by demonstrating how an altered/dysfunctional immunological and inflammatory system may underpin a psychiatric condition. Particularly, several studies specifically investigated the role of a neuroinflammatory biomarker, named C-reactive protein (CRP), in psychiatric disorders. Overall, even though scientific literature so far published still does not appear definitive, CRP is more likely reported to be elevated in several psychiatric disorders, including schizophrenia, mood disorders, anxiety disorders and post-traumatic stress disorder. Moreover, a low-grade inflammation (CRP >3 mg/L) has been more likely observed in a subgroup of patients affected with a more severe psychopathological symptomatology, more treatment resistance and worst clinical mental illness course, strengthening the hypothesis of the need for a different clinical and prognostic characterization based on this concomitant neuroinflammatory predisposition. However, even though further research studies are needed to confirm this preliminary evidence, CRP may represent a potential clinical routine biomarker which could be integrated in the clinical routine practice to better characterize clinical picture and course as well as address clinicians towards a personalized treatment.

Markers of Monocyte Activation, Inflammation, and Microbial Translocation Are Associated with Liver Fibrosis in Alcohol Use Disorder

BACKGROUND

The association between markers of inflammation (interleukin (IL)-6 and IL-10), monocyte activation (sCD163 and sCD14), and microbial translocation (lipopolysaccharide (LPS) and LPS binding protein) and liver fibrosis in patients with alcohol use disorder (AUD) and no overt liver disease is not well established.

METHODS

We studied patients admitted for treatment of AUD at two hospitals in Barcelona. Advanced liver fibrosis (ALF) was defined as FIB-4 > 3.25.

RESULTS

A total of 353 participants (76.3% male) were included and 94 (26.5%) had ALF. In adjusted correlation analyses, sCD163, sCD14, IL-6, IL-10, and LPS binding protein levels directly correlated with FIB-4 values (adjusted correlation coefficients 0.214, 0.452, 0.317, 0.204, and 0.171, respectively). However, LPS levels were inversely associated with FIB-4 (-0.283). All plasma marker levels in the highest quartile, except LPS, were associated with ALF (sCD163, sCD14, IL-6, IL-10, and LPS binding protein: adjusted odds ratio (aOR) 11.49 (95% confidence interval 6.42-20.56), 1.87 (1.11-3.16), 2.99 (1.79-5.01), 1.84 (1.11-3.16), and 2.13 (1.30-3.50), respectively). Conversely, LPS levels in the lowest quartile were associated with ALF (aOR 2.58 (1.48-4.58), p < 0.01).

CONCLUSION

In AUD patients, plasma levels of the markers of inflammation, monocyte activation, and microbial translocation are associated with ALF.

The Immune System through the Lens of Alcohol Intake and Gut Microbiota

The human gut is the largest organ with immune function in our body, responsible for regulating the homeostasis of the intestinal barrier. A diverse, complex and dynamic population of microorganisms, called microbiota, which exert a significant impact on the host during homeostasis and disease, supports this role. In fact, intestinal bacteria maintain immune and metabolic homeostasis, protecting our organism against pathogens. The development of numerous inflammatory disorders and infections has been linked to altered gut bacterial composition or dysbiosis. Multiple factors contribute to the establishment of the human gut microbiota. For instance, diet is considered as one of the many drivers in shaping the gut microbiota across the lifetime. By contrast, alcohol is one of the many factors that disrupt the proper functioning of the gut, leading to a disruption of the intestinal barrier integrity that increases the permeability of the mucosa, with the final result of a disrupted mucosal immunity. This damage to the permeability of the intestinal membrane allows bacteria and their components to enter the blood tissue, reaching other organs such as the liver or the brain. Although chronic heavy drinking has harmful effects on the immune system cells at the systemic level, this review focuses on the effect produced on gut, brain and liver, because of their significance in the link between alcohol consumption, gut microbiota and the immune system.

Cannabis use is associated with monocyte activation (sCD163) in patients admitted for alcohol use disorder treatment

BACKGROUND

The effect of concomitant cocaine and cannabis use on monocyte activation and inflammation in patients with alcohol use disorder (AUD) is unknown.

METHODS

To analyze the impact of cocaine and cannabis use on levels of markers of monocyte activation (sCD163 and sCD14) and systemic inflammation (interleukin-6 [IL-6]) in AUD patients admitted for hospital treatment between 2013 and 2018. Clinical and laboratory parameters were obtained upon admission. IL-6, sCD163, and sCD14 were measured in frozen plasma samples. We performed logistic regression to detect associations between cocaine and cannabis use and markers of monocyte activation and inflammation in the highest quartile.

RESULTS

A total of 289 patients (77.5 % male) were included (median age = 50 years). The median alcohol intake upon admission was 142 g/day. The median duration of AUD was 20 years. Of the 289 patients with AUD, 76 % were active smokers, 23.1 % and 22.1 % concomitantly used cocaine and cannabis, respectively The median levels of IL-6, sCD163, and sCD14 were 4.37 pg/mL, 759 ng/mL, and 1.68 × 10⁶ pg/mL, respectively. We did not detect associations between cocaine use and inflammation or monocyte activation. Cannabis use was associated with a higher odds of having sCD163 levels in the highest quartile (adjusted odds ratio = 2.34, 95 % confidence interval = 1.07-5.15, p = 0.03). Cannabis use was not associated with inflammation.

CONCLUSION

In this series of AUD patients the concomitant use of cannabis use was associated with sCD163 levels that were in the highest quartile, consistent with monocyte activation.