Elevated peripheral blood monocyte fraction in nonalcoholic fatty liver disease

Neutrophils: tissue and circulating signatures of pediatric non-alcoholic fatty liver disease

The recent rise in non-alcoholic fatty liver disease (NAFLD) among children and adolescents led to a thorough investigation of the peculiarities of the cellular infiltrate which characterize the disease at young ages. This review aims to highlight the key involvement of neutrophils in the pathogenesis of pediatric NAFLD and the potential biomarker role of neutrophil-to-lymphocyte ratio (NLR) in the same pediatric disorder. Neutrophils, which are first responders to inflammation, constitute an abundant component of an infiltrate which is particularly disposed within the portal area of children with NAFLD. The involvement of neutrophils in triggering liver fibrosis has been related amongst others to reactive oxygen species (ROS) production, to the stimulation of hepatic stellate cells, and to their synthesis of neutrophil elastase. As immune imbalance characterizes NAFLD, potentially emerging non-invasive biomarkers such as NLR have been proposed for the detection and prognosis of NAFLD. In adults, several studies asserted the role of NLR in the prediction of advancing liver fibrosis and mortality in subjects with NAFLD. In children, data is scarce with contradicting findings, as some studies failed to identify significant shifting in NLR values in children with NAFLD when compared with obese controls without liver impairment. However, NLR seems to significantly increase in children with obesity and different degrees of NAFLD when compared to healthy counterparts and their changes seem to be reversible with weight loss. Still, paucity of pediatric studies calls for future research addressing the role of NLR in predicting NAFLD development and progression in children with obesity.

Overview of Cellular and Soluble Mediators in Systemic Inflammation Associated with Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is currently the most prevalent chronic liver disease in Western countries, affecting approximately 25% of the adult population. This condition encompasses a spectrum of liver diseases characterized by abnormal accumulation of fat in liver tissue (non-alcoholic fatty liver, NAFL) that can progress to non-alcoholic steatohepatitis (NASH), characterized by the presence of liver inflammation and damage. The latter form often coexists with liver fibrosis which, in turn, may progress to a state of cirrhosis and, potentially, hepatocarcinoma, both irreversible processes that often lead to the patient's death and/or the need for liver transplantation. Along with the high associated economic burden, the high mortality rate among NAFLD patients raises interest, not only in the search for novel therapeutic approaches, but also in early diagnosis and prevention to reduce the incidence of NAFLD-related complications. In this line, an exhaustive characterization of the immune status of patients with NAFLD is mandatory. Herein, we attempted to gather and compare the current and relevant scientific evidence on this matter, mainly on human reports. We addressed the current knowledge related to circulating cellular and soluble mediators, particularly platelets, different leukocyte subsets and relevant inflammatory soluble mediators.

2019 Global NAFLD Prevalence: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The increasing rates of obesity and type 2 diabetes mellitus may lead to increased prevalence of nonalcoholic fatty liver disease (NAFLD). We aimed to determine the current and recent trends on the global and regional prevalence of NAFLD.

METHODS

Systematic search from inception to March 26, 2020 was performed without language restrictions. Two authors independently performed screening and data extraction. We performed meta-regression to determine trends in NAFLD prevalence.

RESULTS

We identified 17,244 articles from literature search and included 245 eligible studies involving 5,399,254 individuals. The pooled global prevalence of NAFLD was 29.8% (95% confidence interval [CI], 28.6%-31.1%); of these, 82.5% of included articles used ultrasound to diagnose NAFLD, with prevalence of 30.6% (95% CI, 29.2%-32.0%). South America (3 studies, 5716 individuals) and North America (4 studies, 18,236 individuals) had the highest NAFLD prevalence at 35.7% (95% CI, 34.0%-37.5%) and 35.3% (95% CI, 25.4%-45.9%), respectively. From 1991 to 2019, trend analysis showed NAFLD increased from 21.9% to 37.3% (yearly increase of 0.7%, P < .0001), with South America showing the most rapid change of 2.7% per year, followed by Europe at 1.1%.

CONCLUSIONS

Despite regional variation, the global prevalence of NAFLD is increasing overall. Policy makers must work toward reversing the current trends by increasing awareness of NAFLD and promoting healthy lifestyle environments.

The Effects of Pathogen-Associated Molecular Patterns on Peripheral Blood Monocytes in Patients with Non-alcoholic Fatty Liver Disease

BACKGROUND

Innate immune responses to gut-derived pathogen-associated molecular patterns (PAMPs) have been implicated in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Whether NAFLD patients have increased sensitivity to PAMP exposure has yet to be reported.

METHODS

Peripheral blood mononuclear cell (PBMC)/monocytes were exposed to lipopolysaccharide (LPS), Pam3CSK4, or BSA conjugated palmitate in vitro. Changes in toll-like receptors (TLR), cytokines, and chemokine receptors (CR) expressions were documented by flow cytometry and/or enzyme-linked immunoabsorbent assays (ELISAs).

RESULTS

TLR2 and TLR4 expression were similar at baseline and increased to a similar extent (TLR2) or remained unchanged (TLR4) following PAMP exposure in NAFLD and healthy control (HC) monocytes. Proinflammatory IL-1β and IL-6 levels were similar at baseline but increased in a concentration-dependent manner to a greater extent in NAFLD PBMCs. CCR1 and CCR2 expressions at baseline were similar and decreased to a similar extent in NAFLD and HC monocytes. The extent of PAMP-induced proinflammatory cytokine release correlated with evidence of hepatocyte injury (CK18M30 levels).

DISCUSSION

NAFLD patients have increased proinflammatory cytokine responses following exposure to PAMPs relative to HC subjects. This response is concentration-dependent and correlates with the extent of hepatic injury.

Peripheral immune cells in NAFLD patients: A spyhole to disease progression

Nonalcoholic fatty liver disease (NAFLD) is a worldwide leading cause of chronic liver disease, but we still lack ideal non-invasive tools for diagnosis and evaluation of nonalcoholic steatohepatitis (NASH) and related liver fibrosis in NAFLD population. Systemic immune dysregulations such as metabolic inflammation are believed to play central role in the development of NAFLD, signifying the hope of utilizing quantitative and phenotypic changes in peripheral immune cells among NAFLD patients as a diagnostic tool of NASH and fibrosis. In this review, we summarize the known changes in peripheral immune cells from NAFLD/NASH patients and their potential relationship with NAFLD and NASH progression. Potential challenges and possible solutions for further clinical translation are also discussed.

Controversies and Opportunities in the Use of Inflammatory Markers for Diagnosis or Risk Prediction in Fatty Liver Disease

In the Western society, non-alcoholic fatty liver disease (NAFLD), characterized by the excessive accumulation of fat in the liver, represents the most common cause of chronic liver disease. If left untreated, approximately 15%-20% of patients with NAFLD will progress to non-alcoholic steatohepatitis (NASH), in which lobular inflammation, hepatocyte ballooning and fibrogenesis further contribute to a distorted liver architecture and function. NASH initiation has significant effects on liver-related mortality, as even the presence of early stage fibrosis increases the chances of adverse patient outcome. Therefore, adequate diagnostic tools for NASH are needed, to ensure that relevant therapeutic actions can be taken as soon as necessary. To date, the diagnostic gold standard remains the invasive liver biopsy, which is associated with several drawbacks such as high financial costs, procedural risks, and inter/intra-observer variability in histology analysis. As liver inflammation is a major hallmark of disease progression, inflammation-related circulating markers may represent an interesting source of non-invasive biomarkers for NAFLD/NASH. Examples for such markers include cytokines, chemokines or shed receptors from immune cells, circulating exosomes related to inflammation, and changing proportions of peripheral blood mononuclear cell (PBMC) subtypes. This review aims at documenting and critically discussing the utility of such novel inflammatory markers for NAFLD/NASH-diagnosis, patient stratification and risk prediction.

Dyslipidemic Diet Induces Mobilization of Peripheral Neutrophils and Monocytes That Exacerbate Hemorrhagic Brain Injury and Neuroinflammation

Background: Non-alcoholic fatty liver disease (NAFLD) is a common liver condition characterized by a significant accumulation of lipids in the liver without excessive alcohol consumption. Accumulating evidence suggests a significantly increased risk of intracerebral hemorrhage (ICH) in NAFLD patients. However, it remains poorly understood whether and how NAFLD affects the outcome of hemorrhagic brain injury. Here, we examined the effects of diet-induce NAFLD on ICH injury and neuroinflammation in mice.

Methods: NAFLD was induced in C57BL/6 mice by feeding with a methionine-choline deficient (MCD) diet for 4 weeks. Collagenase and autologous blood models were used to evaluate the effects of NAFLD on ICH injury and neuroinflammation.

Results: MCD diet for 4 weeks induces NAFLD and hyperlipidemia in mice. Mice receiving the MCD diet have aggravated neurological deficits and brain edema after ICH. The augmentation of ICH injury was accompanied by brain infiltration of neutrophils and monocytes and increased production of pro-inflammatory factors. Before ICH, MCD diet-induced mobilization of neutrophils and monocytes in the periphery. Notably, the detrimental effects of NAFLD on ICH injury was ablated in mice receiving antibody depletion of neutrophils and monocytes.

Conclusions: These results suggest that NAFLD exacerbates neuroinflammation and ICH injury.

Blackcurrant (Ribes nigrum) Prevents Obesity-Induced Nonalcoholic Steatohepatitis in Mice

OBJECTIVE

With increasing prevalence of nonalcoholic steatohepatitis (NASH), effective strategies to prevent NASH are needed. This study investigated whether the consumption of blackcurrant (Ribes nigrum) can prevent the development of obesity-induced NASH in vivo.

METHODS

Male C57BL/6J mice were fed a low-fat control diet, a low-fat diet with 6% whole blackcurrant powder, an obesogenic high-fat/high-sucrose control diet (HF), or a high-fat/high-sucrose diet containing 6% whole blackcurrant powder (HF-B) for 24 weeks.

RESULTS

HF significantly increased, whereas HF-B markedly decreased, liver weights and triglyceride. Furthermore, blackcurrant attenuated obesity-induced infiltration of macrophages in the liver, in particular, the M1 type, and also suppressed the hepatic expression of fibrogenic genes and fibrosis. Flow cytometric analysis showed that HF significantly increased the percentages of monocytes of total splenocytes, which was markedly attenuated by blackcurrant. HF-B decreased lipopolysaccharide-stimulated mRNA expression of interleukin 1β and tumor necrosis factor α in splenocytes, compared with those from HF controls. Moreover, the levels of circulating and hepatic miR-122-5p and miR-192-5p, known markers for nonalcoholic fatty liver disease, were significantly increased by HF but decreased by HF-B.

CONCLUSIONS

The study's findings indicate that blackcurrant consumption prevents obesity-induced steatosis, inflammation, and fibrosis in the liver.

Increased intermediate monocyte fraction in peripheral blood is associated with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) currently represents the most common hepatic disease worldwide and is closely linked to cardiovascular disease, obesity and diabetes mellitus. This study aimed to investigate NAFLD and its influence on different monocyte subpopulations to determine the presence of significant associations. A total of 3 monocyte subpopulations were investigated, i.e. classical (CD14++CD16-), intermediate (CD14++CD16+) and non-classical (CD14+CD16++). Of the participants 261 were included in this study (n = 53 with NAFLD, n = 208 controls). Ultrasonography was used to diagnose NAFLD and exclude other morphologic causes of liver diseases and other tests (including medical history inquiries and detection of hepatitis virus) were performed to exclude other causes of parenchymal liver disease. Classical inflammatory and metabolic-related NAFLD biomarkers were also determined. In contrast to the healthy control group, the intermediate monocyte fraction was increased in NAFLD patients (p = 0.032), while the classical monocyte fraction was decreased (p = 0.025). Intermediate monocyte fraction, body mass index (BMI) and tumor necrosis factor alpha (TNF-α) were independent risk factors for NAFLD. Classical, non-classical and intermediate monocytes fraction were strongly associated with age, triglyceride, and waist circumference. This study suggests that the intermediate monocyte fraction in peripheral blood is likely related to the aggravation of NAFLD.

Serum ferritin as a non-invasive marker in the prediction of hepatic fibrosis among Egyptian patients with non-alcoholic fatty liver disease

Background and Aim

Many studies have found a relationship between hepatic iron, serum ferritin, and non‐alcoholic fatty liver disease (NAFLD) or its progress. The aim of this study is to assess the value of serum ferritin as a non‐invasive marker in the prediction of hepatic fibrosis in NAFLD.

Methods

This study included 113 subjects who were classified into three groups. Group I included 30 healthy subjects as control with no clinical, radiological, and histological features of NAFLD. Group II included 31 NAFLD patients without hepatic fibrosis. Group III included 52 patients with hepatic fibrosis on top of NAFLD.

Results

Serum ferritin was determined using ferritin ELISA kit. Fibrosis 4 score was calculated. Liver biopsy was conducted for included patients. Significantly higher levels of serum ferritin were found in patients with hepatic fibrosis on top of NAFLD than controls. Receiver operating characteristic curve analysis revealed that an optimum cutoff level of 51.95 ng/mL was the best to predict fibrosis on top of NAFLD with diagnostic sensitivity and specificity of 65% and 60%, respectively, and area under the curve = 0.658.

Conclusion

Higher serum ferritin was found in patients with hepatic fibrosis on top of NAFLD. Serum ferritin was found to be a predictor of fibrosis on top of NAFLD with moderate sensitivity and specificity.

Associations between White Blood Cell Count and the Development of Incidental Nonalcoholic Fatty Liver Disease

Aims. Chronic low-grade inflammation is thought to be associated with the pathogenesis of nonalcoholic fatty liver disease (NAFLD). This study aimed to determine the association between serum white blood cell (WBC) counts and the development of incidental NAFLD. Methods. In this retrospective longitudinal cohort study, we recruited participants who underwent abdominal ultrasonography and blood samplings during medical checkups in both 2005 and 2010. A total of 2,216 subjects were included in our analyses. Results. The prevalence of NAFLD in 2010 increased steadily in conjunction with increasing WBC counts in 2005 after adjustment for body mass index (BMI) [odds ratio (OR) 2.44, 95% confidence interval (CI) = 1.49–4.00 for women and OR 2.42, 95% CI = 1.61–3.63 for men, lowest quartile versus highest quartile]. Multivariate regression analysis after adjusting for age, BMI, hypertension, smoking, triglycerides, HDL cholesterol, and glucose levels revealed that NAFLD was significantly associated with the highest WBC quartile compared to the lowest quartile [OR 1.85, 95% CI, 1.10−3.10 for women and OR 1.68, 95% CI, 1.08−2.61 for men]. Conclusions. We demonstrated that the risk of developing NAFLD was significantly associated with WBC counts independently of metabolic factors. This finding provides novel evidence indicating that serum WBC counts may be potential surrogate markers of NAFLD.

Neutrophil-to-lymphocyte ratio is not a predictor of liver histology in patients with nonalcoholic fatty liver disease

OBJECTIVES

It has been reported that the neutrophil-to-lymphocyte ratio (NLR) can be measured relatively easily and can serve as a valuable index for much clinical pathology. The aim of this study was to investigate the association between NLR and hepatic histological findings in patients with nonalcoholic fatty liver disease (NAFLD).

DESIGN AND METHODS

A total of 226 consecutive patients with biopsy-proven NAFLD [nonalcoholic steatohepatitis (NASH, n=105), borderline-NASH (n=74), and simple steatosis (n=47)] were enrolled. NASH and fibrosis were diagnosed histologically using the NAFLD Clinical Research Network criteria.

RESULTS

Significant differences were found in aspartate aminotransferase (P<0.001), alanine aminotransferase (P<0.001) levels, and white blood cell (P=0.007) and neutrophil counts (P=0.042) between the three groups of patients. In addition, significantly higher BMI (P=0.024), waist circumference (P=0.011), aspartate aminotransferase (P=0.003), alanine aminotransferase (P=0.005), insulin (P=0.008), and homeostasis model assessment-insulin resistance (P=0.009) levels were found in patients with fibrosis (n=133) in comparison with those without fibrosis (n=93). There was no correlation between NLR and glucose, homeostasis model assessment-insulin resistance, lipid parameters, and the NAFLD activity score. Analysis of the NLR in relation to histological findings also showed no association between these parameters.

CONCLUSION

To the best of our knowledge, this is the largest study that has investigated these relationships in this clinically relevant condition. The findings of the present study show that NLR is not associated with the severity of hepatic inflammation or fibrosis and thus cannot be recommended as a surrogate marker of liver injury in patients with NAFLD.

Association of peripheral total and differential leukocyte counts with obesity-related complications in young adults

OBJECTIVE

Obesity has been demonstrated to be associated with elevated leukocytes in adults and children. This study assessed the associations between peripheral total and differential leukocyte counts and obesity-related complications in young adults.

METHODS

12 obese (median age 21.5 (range 19-28) years, median BMI 35.7 (range 32.0-44.9) kg/m(2)) and 11 normal (median age 23 (range 18-27) years, median BMI 19.5 (range 18.1-21.7) kg/m(2)) adults were enrolled. Complete blood count and serum levels of liver enzymes, fasting blood glucose, insulin and lipids were measured, and the homeostasis model assessment of insulin resistance was calculated. Fat mass was calculated using a bioimpedance analysis device, and ultrasonography was performed to measure fat thickness and to detect fatty change of the liver.

RESULTS

Total leukocyte and monocyte counts were significantly increased in obese young adults. Total leukocyte count was associated with liver enzyme levels, insulin resistance as well as visceral and subcutaneous fat thickness. Neutrophil count was associated with insulin resistance. Lymphocyte count was associated with serum liver enzymes, insulin resistance, and dyslipidemia. Monocyte count was associated with serum liver enzyme, insulin resistance, visceral and subcutaneous fat thickness, body fat mass, and percentage body fat.

CONCLUSION

The results of this study suggest that chronic low-grade systemic inflammation is associated with obesity-related complications such as nonalcoholic fatty liver disease, insulin resistance, and dyslipidemia in young adults.