NAFLD is related to Post-prandial Triglyceride-enrichment of HDL Particles in Association with Endothelial and HDL Dysfunction

Association between circulating biomarkers and non-alcoholic fatty liver disease: An integrative Mendelian randomization study of European ancestry

BACKGROUND AND AIM

Circulating biomarkers provide potential diagnostic or prognostic information on disease presentation, progression or both. Early detection of circulating risk biomarkers is critical for non-alcoholic fatty liver disease (NAFLD) prevention. We aimed to systematically assess the potential causal relationship of genetically predicted 60 circulatory biomarkers with NAFLD using a two-sample Mendelian randomization (MR) design.

METHODS AND RESULTS

We extracted instrumental variables for 60 circulating biomarkers, and obtained genome-wide association data for NAFLD from 3 sources [(including Anstee, FinnGen and UK Biobank (N ranges: 19264-377988)] among individuals of European ancestry. Our primary method was inverse-variance weighted (IVW) MR, with a series of additional and sensitivity analyses to test the hypothesis of MR. MR results showed that genetically predicted higher density lipoprotein-cholesterol (odds ratio (OR) = 0.86, 95% confidence interval (CI): 0.77-0.96) and vitamin D (OR = 0.39, 95% CI: 0.19-0.78) levels decreased the risk of NAFLD, whereas genetically predicted higher alanine (OR = 1.68, 95% CI: 1.21-2.33), histidine (OR = 1.21, 95% CI: 1.00-1.46), lactate (OR = 2.64, 95% CI: 1.09-6.39), triglycerides (OR = 1.16, 95% CI: 1.05-1.13), ferritin (OR = 1.17, 95% CI: 1.01-1.37), serum iron (OR = 1.23, 95% CI: 1.07-1.41) and transferrin saturation (OR = 1.16, 95% CI: 1.05-1.29), component 4 (OR = 1.10, 95% CI: 1.01-1.20), interleukin-1 receptor antagonist (OR = 1.12, 95% CI: 1.04-1.21) and interleukin-6 (OR = 1.62, 95% CI: 1.14-2.30) levels increased the risk of NAFLD.

CONCLUSIONS

The findings might aid in elucidating the underlying processes of these causal relationships and provide strong evidence for focusing on high-risk populations and the therapeutic management of specific biomarkers.

A decreased level of high-density lipoprotein is a possible risk factor for type 2 diabetes mellitus: A review

Introduction

Type 2 diabetes mellitus (T2DM) is characterized primarily by dyslipidemia and hyperglycemia due to insulin resistance. High-density lipoprotein (HDL) play a significant role in preventing the incidence of dyslipidemia and its complications. HDL has different protective functions, such as reducing oxidation, vascular inflammation, and thrombosis; additionally, its anti-diabetic role is one of the most significant recent discoveries about HDL and some of its constituent lipoproteins.

Methods

This research reviews ongoing studies and preliminary investigations into the assessment of relation between decreased level of HDL and T2DM.

Results

The levels of HDL and its functions contribute to glucose hemostasis and the development of T2DM through four possible mechanisms, including insulin secretion by beta cells, peripheral insulin sensitivity, non-insulin-dependent glucose uptake, and adipose tissue metabolic activity. Additionally, the anti-oxidant properties of HDL protect beta cells from apoptosis caused by oxidative stress and inflammation induced by low-density lipoprotein, which facilitate insulin secretion.

Conclusion

Therefore, HDL and its compositions, especially Apo A-I, play an important role in regulating glucose metabolism, and decreased levels of HDL can be considered a risk factor for DM. Different factors, such as hypoalphalipoproteinemia that manifests as a consequence of genetic factors, such as Apo A-I deficiency, as well as secondary causes arising from lifestyle choices and underlying medical conditions that decrease the level of HDL, could be associated with DM. Moreover, intricate connections between HDL and diabetic complications extend beyond glucose metabolism to encompass complications like cardiovascular disease and kidney disease. Therefore, the exact interactions between HDL level and DM should be evaluated in future studies.

Relationship between Uric Acid to High Density Lipoprotein Cholesterol Ratio and Nonalcoholic Fatty Liver Disease in Nonoverweight/Obese Patients with Type 2 Diabetes

AIMS

To investigate the relationship between uric acid to high-density lipoprotein cholesterol ratio (UHR) levels and nonalcoholic fatty liver disease (NAFLD) in nonoverweight/obese patients with type 2 diabetes.

METHODS

A retrospective study was designed including a total of 343 inpatients with type 2 diabetes whose BMI<24 kg/m2. The population was divided into three groups as the UHR tertiles. Logistic regression analysis was performed to estimate odds ratios (ORs) of UHR for NAFLD. ROC curve analysis was used to estimate the diagnostic value of UHR for NAFLD.

RESULTS

The prevalence rat of NAFLD enhanced progressively from the tertile 1 to tertile 3 of UHR (30.70% vs. 56.52% vs. 73.68%). Logistic regression analysis showed that participants in the higher UHR groups, compared with those in the first tertile group, had higher occurrence risks for NAFLD. The positive association between UHR and NAFLD was independent of age, BMI, blood pressure, hepatic enzymes, and other components of metabolic disorders. ROC curve analysis showed that the area under curve (AUC), sensitivity, and specificity for UHR were 0.697, 0.761, and 0.553, respectively.

CONCLUSIONS

In type 2 diabetic patients without overweight or obesity, UHR is significantly associated with NAFLD and can be used as a novel and useful predictor for NAFLD onset.

Postprandial triglycerides and fibroblast growth factor 19 as potential screening tools for paediatric non-alcoholic fatty liver disease

BACKGROUND

Better screening tools for paediatric NAFLD are needed. We tested the hypothesis that the postprandial triglyceride (TG) and fibroblast growth factor 19 (FGF19) response to an abbreviated fat tolerance test (AFTT) could differentiate adolescents with NAFLD from peers with obesity and normal weight.

METHODS

Fifteen controls with normal weight (NW), 13 controls with obesity (OB) and 9 patients with NAFLD completed an AFTT. Following an overnight fast, participants consumed a high-fat meal. TG and FGF19 were measured at baseline and 4 h post-meal. Liver steatosis and fibrosis were measured via Fibroscan.

RESULTS

Fasting TG and FGF19 did not differ among groups; 4 h TG in the NAFLD and OB groups were greater (197 ± 69 mg/dL; 157 ± 72 mg/dL, respectively) than NW (105 ± 45 mg/dL; p < 0.05) and did not differ from one another. Within the entire cohort, 4 h TG were stratified by high and low steatosis. Adolescents with high steatosis had 98% greater 4 h TG than adolescents with low steatosis. 4 h FGF19, but not fasting FGF19, was higher in children with low steatosis compared with high steatosis (p < 0.05). Using area under the receiver operating curve (AUROC), the only biochemical outcome with diagnostic accuracy for NAFLD was 4 h TG (0.77 [95% CI: 0.60-0.94; p = 0.02]).

CONCLUSIONS

The postprandial TG response is increased in adolescents with obesity with hepatic steatosis, with or without NAFLD. Our preliminary analysis demonstrates 4 h TG differentiate patients with NAFLD from those without, supporting a role for the AFTT as a screening tool for paediatric NAFLD.

A prolonged fast improves overnight substrate oxidation without modulating hepatic glycogen in adults with and without nonalcoholic fatty liver: A randomized crossover trial

OBJECTIVE

Increasing overnight fasting time seems a promising strategy to improve metabolic health in individuals with nonalcoholic fatty liver (NAFL). Mechanisms underlying the beneficial effects of fasting may be related to larger fluctuations in hepatic glycogen and higher fat oxidation. This study investigated whether prolonging an overnight fast depletes hepatic glycogen stores and improves substrate metabolism in individuals with NAFL and healthy lean individuals.

METHODS

Eleven individuals with NAFL and ten control individuals participated in this randomized crossover trial. After a 9.5-hour or 16-hour fast, hepatic glycogen was measured by using carbon-13 magnetic resonance spectroscopy, and a meal test was performed. Nocturnal substrate oxidation was measured with indirect calorimetry.

RESULTS

Extending fasting time led to lower nocturnal carbohydrate oxidation and higher fat oxidation in both groups (intervention × time, p < 0.005 for carbohydrate and fat oxidation). In both arms, the respiratory exchange ratio measured during the night remained higher in the group with NAFL compared with the control group (population p < 0.001). No changes were observed in hepatic glycogen depletion with a prolonged overnight fast in the group with NAFL or the control group.

CONCLUSIONS

These results suggest that acutely prolonging the overnight fast can improve overnight substrate oxidation and that these alterations are not mediated by changes in hepatic glycogen depletion.

Associations between Endothelial Lipase, High-Density Lipoprotein, and Endothelial Function Differ in Healthy Volunteers and Metabolic Syndrome Patients

Metabolic syndrome (MS) is characterized by endothelial- and high-density lipoprotein (HDL) dysfunction and increased endothelial lipase (EL) serum levels. We examined the associations between EL serum levels, HDL (serum levels, lipid content, and function), and endothelial function in healthy volunteers (HV) and MS patients. Flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), serum levels of HDL subclasses (measured by nuclear magnetic resonance (NMR) spectroscopy), and EL serum levels differed significantly between HV and MS patients. The serum levels of triglycerides in large HDL particles were significantly positively correlated with FMD and NMD in HV, but not in MS patients. Cholesterol (C) and phospholipid (PL) contents of large HDL particles, calculated as HDL1-C/HDL1-apoA-I and HDL1-PL/HDL1-apoA-I, respectively, were significantly negatively correlated with FMD in HV, but not in MS patients. Cholesterol efflux capacity and arylesterase activity of HDL, as well as EL, were correlated with neither FMD nor NMD. EL was significantly negatively correlated with HDL-PL/HDL-apoA-I in HV, but not in MS patients, and with serum levels of small dense HDL containing apolipoprotein A-II in MS patients, but not in HV. We conclude that MS modulates the association between HDL and endothelial function, as well as between EL and HDL. HDL cholesterol efflux capacity and arylesterase activity, as well as EL serum levels, are not associated with endothelial function in HV or MS patients.

The Role of Non-Alcoholic Fatty Liver Disease in Infections

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease, affecting one third of the Western population. The hallmark of the disease is excessive storage of fat in the liver. Most commonly, it is caused by metabolic syndrome (or one of its components). Even though the development of NAFLD has multiple effects on the human organism resulting in systemic chronic low-grade inflammation, this review is focused on NAFLD as a risk factor for the onset, progression, and outcomes of infectious diseases. The correlation between NAFLD and infections is still unclear. Multiple factors (obesity, chronic inflammation, altered immune system function, insulin resistance, altered intestinal microbiota, etc.) have been proposed to play a role in the development and progression of infections in people with NAFLD, although the exact mechanism and the interplay of mentioned factors is still mostly hypothesized. In this article we review only the selection of well-researched topics on NAFLD and infectious diseases (bacterial pneumonia, COVID, H. pylori, urinary tract infections, C. difficile, bacteremia, hepatitis B, hepatitis C, HIV, and periodontitis).

Correlation between Component Factors of Non-Alcoholic Fatty Liver Disease and Metabolic Syndrome in Nurses: An Observational and Cross-Sectional Study

This study aimed to understand the correlation between non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome in nurses. Questionnaires were used to eliminate individuals with a daily drinking habit, hepatitis B or C, or incomplete data. A total of 706 valid samples were obtained. The prevalence of NAFLD among nurses was 36.8%. Nurses with a greater age (OR = 1.08, 95% CI: 1.01-1.16), obese BMI (OR = 23.30, 95% CI: 8.88-61.10), overweight BMI (OR = 3.89, 95% CI: 2.15-7.04), waist circumference exceeding the standard (OR = 2.10, 95% CI: 1.14-3.87), fasting blood glucose 100-125 mg/dL (OR = 4.09, 95% CI: 1.19-14.03), and overly low HDL-C (OR = 2.01, 95% CI: 1.05-3.85) were at greater risk of NAFLD. Furthermore, male nurses (OR = 6.42, 95% CI: 1.07-38.70), nurses with triglycerides over 150 mg/dL (OR = 4.80; 95% CI: 1.05-21.95), and nurses with HDL-C lower than the standard (OR = 5.63, 95% CI: 1.35-23.49) were at greater risk of moderate/severe NAFLD. Among younger nurses, those of greater age, male nurses, obese and overweight nurses, and those with a waist circumference exceeding the standard, 100-125 mg/dL, overly low HDL-C, and triglycerides over 150 mg/dL should consider the possibility that they have NAFLD.

Assessing the longitudinal association between the GGT/HDL-C ratio and NAFLD: a cohort study in a non-obese Chinese population

BACKGROUND

A cross-sectional association between the combination indicator of high-density lipoprotein cholesterol (HDL-C) and gamma-glutamyl transferase (GGT) and fatty liver has been described in several recent studies, and this study aims to further evaluate the longitudinal relationship between the ratio of GGT to HDL-C (GGT/HDL-C ratio) and nonalcoholic fatty liver disease (NAFLD).

METHODS

This cohort study included 12,126 individuals without NAFLD at baseline, followed prospectively for 5 years, and the endpoint of interest was new-onset NAFLD. The relationship of the GGT/HDL-C ratio with new-onset NAFLD and the shape of the association was assessed by Cox regression models and restricted cubic spline (RCS) regression, respectively. Time-dependent receiver operator characteristics (ROC) curves were constructed to evaluate the predictive value of GGT, HDL-C, GGT/HDL-C ratio and BMI for the occurrence of NAFLD at different time points in the future.

RESULTS

The prevalence of NAFLD was 72.46/1000 person-years during the 5-year follow-up period. Results of multivariate Cox regression analysis showed a positive association of the GGT/HDL-C ratio with new-onset NAFLD after adequate adjustment of the related confounding factors, and the degree of correlation was slightly higher than that of GGT, and further subgroup analysis found that this association was more significant in the population with elevated systolic blood pressure (SBP). In addition, we also found a nonlinear relationship of the GGT/HDL-C ratio with the risk of new-onset NAFLD using the RCS regression, where the saturation threshold was about 31.79 U/mmol. Time-dependent ROC analysis results showed that the GGT/HDL-C ratio was increasingly valuable in predicting NAFLD over time, and was better than HDL-C in predicting NAFLD in the early stage (1-3 years), but was not superior to BMI and GGT.

CONCLUSIONS

In this large longitudinal cohort study based on a Chinese population, our results supported that the GGT/HDL-C ratio was positively and nonlinearly associated with the risk of new-onset NAFLD in a non-obese population. In the assessment of future NAFLD risk, the GGT/HDL-C ratio was slightly better than GGT alone; However, the GGT/HDL-C ratio did not appear to have a significant advantage over GGT and BMI alone in predicting NAFLD.

Banting memorial lecture 2022: 'Type 2 diabetes and nonalcoholic fatty liver disease: Partners in crime'

Nonalcoholic fatty liver disease (NAFLD) was first described in the 1980s, but in the 21st century, NAFLD has become a very common condition. The explanation for this relatively recent problem is in large part due to the recent epidemic of obesity and type 2 diabetes (T2DM) increasing the risk of NAFLD. NAFLD is a silent condition that may not become manifest until severe liver damage (fibrosis or cirrhosis) has occurred. Consequently, NAFLD and its complications often remain undiagnosed. Research evidence shows that NAFLD is extremely common and some estimates suggest that it occurs in up to 70% of people with T2DM. In the last 5 years, it has become evident that NAFLD not only increases the risk of cirrhosis, primary liver cancer and end-stage liver disease, but NAFLD is also an important multisystem disease that has major implications beyond the liver. NAFLD increases the risk of incident T2DM, cardiovascular disease, chronic kidney disease and certain extra-hepatic cancers, and NAFLD and T2DM form part of a vicious spiral of worsening diseases, where one condition affects the other and vice versa. Diabetes markedly increases the risk of liver fibrosis and liver fibrosis is the most important risk factor for hepatocellular carcinoma. It is now possible to diagnose liver fibrosis with non-invasive tools and therefore it is important to have clear care pathways for the management of NAFLD in patients with T2DM. This review summarises key recent research that was discussed as part of the Banting lecture at the annual scientific conference in 2022.

A single, high-fat meal adversely affects postprandial endothelial function: a systematic review and meta-analysis

BACKGROUND

Endothelial dysfunction is a predictive risk factor for the development of atherosclerosis and is assessed by flow-mediated dilation (FMD). Although it is known that NO-dependent endothelial dysfunction occurs after consuming a high-fat meal, the magnitude of the effect and the factors that affect the response are unquantified.

OBJECTIVES

We conducted a systematic review and meta-analysis exploring the quantitative effects of a single high-fat meal on endothelial function and determined the factors that modify the FMD response.

METHODS

Six databases were systematically searched for original research published up to January 2022. Eligible studies measured fasting and postprandial FMD following consumption of a high-fat meal. Meta-regression was used to analyze the effect of moderator variables.

RESULTS

There were 131 studies included, of which 90 were suitable for quantitative meta-analysis. A high-fat meal challenge transiently caused endothelial dysfunction, decreasing postprandial FMD at 2 hours [-1.02 percentage points (pp); 95% CI: -1.34 to -0.70 pp; P < 0.01; I2 = 93.3%], 3 hours [-1.04 pp; 95% CI: -1.48 to -0.59 pp; P < 0.001; I2 = 84.5%], and 4 hours [-1.19 pp; 95% CI: -1.53 to -0.84 pp; P < 0.01; I2 = 94.6%]. Younger, healthy-weight participants exhibited a greater postprandial reduction in the FMD percentage change than older, heavier, at-risk groups after a high-fat meal ( P < 0.05). The percentage of fat in the meals was inversely associated with the magnitude of postprandial changes in FMD at 3 hours (P < 0.01).

CONCLUSIONS

A single, high-fat meal adversely impacts endothelial function, with the magnitude of the impact on postprandial FMD moderated by the fasting FMD, participant age, BMI, and fat content of the meal. Recommendations are made to standardize the design of future postprandial FMD studies and optimize interpretation of results, as high-fat meals are commonly used in clinical studies as a challenge to assess endothelial function and therapeutics. This trial was registered at PROSPERO as CRD42020187244.

Ficus hirta Vahl. Ameliorates Nonalcoholic Fatty Liver Disease through Regulating Lipid Metabolism and Gut Microbiota

Nonalcoholic fatty liver disease (NAFLD) has gradually become one of the most serious liver diseases threatening human health in the world. Currently, Chinese herbal medicine is a potentially important treatment option for NAFLD, and the development of effective Chinese herbal medicine has a good prospect. Previous studies have suggested that Ficus hirta Vahl. (FV) has various protective effects on the liver. In this study, we investigated the therapeutic outcomes of FV treatment for the liver disease and its underlying mechanism using HepG2 cell lines induced by palmitate (PA) and mouse model fed with high-fat diet (HFD). FV mainly exerts pharmacological effects by mediating lipid metabolism and inflammation. During the lipid metabolism regulation process, CD36, SREBP-1, SCD1, PPAR γ, ACOX1, and CPT1α are the key factors related to the healing effects of FV on NAFLD. During the inflammation process, the downregulation of IL-6, IL-1β, and TNF-α is involved in alleviation of NAFLD. Furthermore, CD36 overexpression promotes lipid abnormal metabolism and inflammation in PA-induced HepG2 cells, while CD36 knockdown and FV supplementation reverse these responses. In addition, FV also modulates gut microbiota composition, such as Allobaculum, Faecalibaculum, and Butyricicoccus in HFD-fed mice. In summary, our findings demonstrated that FV exerted a beneficial preventive and therapeutic effect on NAFLD by improving lipid metabolism and inflammation as well as regulating the structure of gut microbiota, and therefore, FV may be a candidate for the treatment of NAFLD.

Effective, disease-modifying, clinical approaches to patients with mild-to-moderate hypertriglyceridaemia

Plasma triglyceride concentration is easily, inexpensively, and accurately measured, and when elevated is a highly informative disease marker that identifies individuals who frequently have a host of underlying metabolic, inflammatory, and atherogenic risk factors. Although this concept aligns with much that has been discussed regarding the metabolic syndrome, individuals identified with mild-to-moderate hypertriglyceridaemia on a screening lipid profile are not necessarily recognised as having features of the metabolic syndrome and frequently do not receive definitive, meaningful, disease-modifying therapy. This treatment would include (1) lifestyle modification; (2) LDL-lowering therapies to aggressively treat elevated apolipoprotein B-containing particles; (3) antihypertensive therapies that have optimal therapeutic profiles for those individuals with metabolic syndrome; (4) icosapent ethyl for those individuals at high risk, particularly patients with established atherosclerotic cardiovascular disease who have residual hypertriglyceridaemia despite treatment with appropriate LDL-lowering therapies; (5) preferential use of cardiovascular protective diabetes therapies, in individuals with diabetes; and (6) antithrombotic therapies for secondary prevention of atherosclerotic cardiovascular disease in the context of high vascular disease risk and diabetes. Several emerging therapies, such as novel weight reducing, anti-inflammatory, lipid-modifying therapies, and therapies targeting the progression of non-alcoholic fatty liver disease, could also soon enter the clinical arena for patients with mild-to-moderate hypertriglyceridaemia and associated metabolic syndrome.

Hepatic Lipid Metabolism Disorder and Atherosclerosis

Lipid metabolism disorder plays a fundamental role in the pathogenesis of atherosclerosis. As the largest metabolic organ of the human body, liver has a key role in lipid metabolism by influencing fat production, fat decomposition, and the intake and secretion of serum lipoproteins. Numerous clinical and experimental studies have indicated that the dysfunction of hepatic lipid metabolism is closely tied to the onset of atherosclerosis. However, the identity and functional role of hepatic lipid metabolism responsible for these associations remain unknown. This review presented that cholesterol synthesis, cholesterol transport, and the metabolism of triglyceride, lipoproteins, and fatty acids are all associated with hepatic lipid metabolism and atherosclerosis. Moreover, we also discussed the roles of gut microbiota, inflammatory response, and oxidative stress in the pathological association between hepatic lipid metabolism and atherosclerosis. These significant evidences support strongly that hepatic lipid metabolism disorders may increase the risk of atherosclerosis.

Lipotoxicity: a driver of heart failure with preserved ejection fraction?

Heart failure with preserved ejection fraction (HFpEF) is a growing public health concern, with rising incidence alongside high morbidity and mortality. However, the pathophysiology of HFpEF is not yet fully understood. The association between HFpEF and the metabolic syndrome (MetS) suggests that dysregulated lipid metabolism could drive diastolic dysfunction and subsequent HFpEF. Herein we summarise recent advances regarding the pathogenesis of HFpEF in the context of MetS, with a focus on impaired lipid handling, myocardial lipid accumulation and subsequent lipotoxicity.

Comparisons of the effects of different flaxseed products consumption on lipid profiles, inflammatory cytokines and anthropometric indices in patients with dyslipidemia related diseases: systematic review and a dose-response meta-analysis of randomized controlled trials

BACKGROUND

Flaxseed is widely used as a functional food for its rich sources of linolenic acid, lignans and dietary fibers in the world. This systematic review and dose-response meta-analysis on randomized controlled trials (RCTs) is first to evaluate effects of different flaxseed products (whole flaxseed, oil and lignans) on lipid profiles, inflammatory and anthropometric parameters in patients with dyslipidemia related diseases.

METHODS

Literature search was performed in PubMed, Embase, Cochrane Central, Scopus, and Web of Science from the inception dates to January, 2020. Weighted mean differences with the 95% confidence interval (CI) were pooled using fix or random-effects models.

RESULTS

Thirty-one RCTs involving 1,698 participants were included. The present meta-analysis revealed that flaxseed consumption had an overall beneficial effect on serum TC, LDL-C, TG, apo B and IL-6 in patients with dyslipidemia related diseases, but not on apo A, HDL-C, hs-CRP, CRP and anthropometric indices. However, different flaxseed products showed obviously different effects. Whole flaxseed supplementation significantly reduced TC (- 11.85 mg/dl, 95% CI - 20.12 to - 3.57, P = 0.005), LDL-C (- 10.51 mg/dl, 95% CI - 14.96 to - 6.06, P < 0.001), TG (- 19.77 mg/dl, 95% CI - 33.61 to - 5.94, P = 0.005), apolipoprotein B (- 5.73 mg/dl, 95% CI - 7.53 to - 3.93, P < 0.001), TC/HDL-C (- 0.10, 95% CI - 0.19 to - 0.003, P = 0.044) and weight (- 0.40 kg, 95% CI - 0.76 to - 0.05, P = 0.027); Lignans supplementation significantly reduced TC (- 17.86 mg/dl, P = 0.004), LDL-C (- 15.47 mg/dl, P < 0.001) and TC/HDL-C (- 0.45, P = 0.04). Although flaxseed oil supplementation had no such lowering-effect on lipid, meta-analysis revealed its lowering-effect on IL-6 (- 0.35 pg/ml, P = 0.033) and hs-CRP (- 1.54 mg/l, P = 0.004). Subgroup analysis revealed that whole flaxseed decreased TC, LDL-C and TG levels irrespective of country and the intervention time prescribed, but was more pronounced when the dose of whole flaxseed was ≤ 30 g/day (TC: WMD - 13.61 mg/mL; LDL-C: WMD - 10.52 mg/mL; TG: WMD - 23.52 mg/mL), rather not a dose > 30 g/day. Moreover, a linear relationship between dose of whole flaxseed and absolute changes in C-reactive protein (P = 0.036) and a nonlinear relationship between with IL-6 (P < 0.001) were detected.

CONCLUSIONS

Flaxseed intervention suggested the positive effects on lipid profiles, inflammatory cytokines and anthropometric indices in patients with dyslipidemia related diseases. Of these, whole flaxseed and lignans play an important role in reducing blood lipid, while flaxseed oil mainly plays in anti-inflammatory. Lipid- and weight-lowering was significant when whole flaxseed was consumed at doses < 30 mg/d, for lipid status with mixed dyslipidemia and patients with BMI > 25.

A Novel Identified Peptide Hormone "Metabolitin" Attenuates Lipid Absorption in the Small Intestine of Diabetic Mice with Nonalcoholic Fatty Liver Disease by Regulating Neurotensin and AMPK Signaling Pathway

AIM

The purpose of this study was to explore the effect of a novel identified peptide hormone "metabolitin" on lipid absorption in the small intestine of mice with type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD) and potential mechanisms.

METHODS

T2DM was induced in mice by 4-6 weeks of high-fat diets followed by intraperitoneal injection of 35 mg/kg STZ. NAFLD was induced in diabetic mice by a month of high-fat diets. Oral administration of 4 pmol/g or 12 pmol/g metabolitin every two days was performed during one-month high-fat diets. Triglyceride (TG) and total cholesterol (TC) detection and Oil Red O staining were performed to evaluate lipid absorption. The neurotensin (NT) levels in the intestinal tissues and serum were determined by ELISA. Lipogenesis- and lipolysis-related proteins, AMP-activated protein kinase (AMPK), and p-AMPK were examined by Western blot analysis.

RESULTS

It was found that glucose tolerance test (GTT), insulin tolerance test (ITT), TG, and TC indicated lower levels in the serum of NAFLD/T2DM mice receiving 4 pmol/g and 12 pmol/g metabolitin compared to the mice receiving normal saline (P < 0.05). No significant difference was noted in the TC level of the feces among mice with different diets (P > 0.05), but compared to NAFLD/T2DM mice with normal saline, the mice administrated with 4 pmol/g and 12 pmol/g metabolitin revealed much higher TG levels in the feces (P < 0.05). The results of Oil Red O staining revealed that the intestinal epithelial cells of NAFLD/T2DM mice receiving 12 pmol/g metabolitin indicated resistance to lipid absorption and the area of staining was smaller than that of NAFLD/T2DM mice with normal saline (P < 0.05). The NAFLD/T2DM mice receiving 4 pmol/g and 12 pmol/g metabolitin showed a higher extent of p-AMPK concomitant with lower levels of NT in the serum and small intestine than the mice with normal saline (P < 0.05). Western blot analysis also suggested that NAFLD/T2DM mice receiving 4 pmol/g and 12 pmol/g metabolitin revealed lower expressions in fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), stearoyl-CoA desaturase-1 (SCD-1), and sterol regulatory element-binding transcription factor-1 (SREBP1) proteins and higher expressions in carnitine palmitoyltransferase 1 (CPT1), peroxisome proliferator-activated receptor alpha (PPARα), and fatty acid translocase (CD36) proteins than NAFLD/T2DM mice with normal saline (P < 0.05).

CONCLUSION

According to the data we observed, oral administration of metabolitin could attenuate lipid absorption in the small intestine of NAFLD/T2DM mice, which may be a novel therapeutic approach for NAFLD/T2DM.

Mechanisms of Atherosclerosis Induced by Postprandial Lipemia

Postprandial lipemia plays an important role in the formation, occurrence, and development of atherosclerosis, and it is closely related to coronary heart disease and other diseases involving endothelial dysfunction, oxidative stress, inflammation, and other mechanisms. Therefore, it has become a focus area for further research. The studies on postprandial lipemia mainly include TG, TRL, VLDL, CM, and remnant cholesterol. Diurnal triglyceride patterns and postprandial hyperlipidemia are very relevant and are now insufficiently covered. The possible mechanisms between postprandial lipemia and cardiovascular disease have been reviewed in this article by referring to relevant literature in recent years. The research progress on the effects of postprandial lipemia on endothelial function, oxidative stress, and inflammation is highlighted. The intervention of postprandial lipemia is discussed. Non-medicinal intervention such as diet and exercise improves postprandial lipemia. As medicinal intervention, statin, fibrate, ezetimibe, omega-3 fatty acids, and niacin have been found to improve postprandial lipid levels. Novel medications such as pemafibrate, PCSK9, and apoCIII inhibitors have been the focus of research in recent years. Gut microbiota is closely related to lipid metabolism, and some studies have indicated that intestinal microorganisms may affect lipid metabolism as environmental factors. Whether intervention of gut microbiota can reduce postprandial lipemia, and therefore against AS, may be worthy of further study.

Varied Relationship of Lipid and Lipoprotein Profiles to Liver Fat Content in Phenotypes of Metabolic Associated Fatty Liver Disease

BACKGROUND

Progressive overloads of intrahepatic triglycerides are related to metabolic dysregulation of multiple lipid and lipoprotein profiles, but whether similar dose effects are found in each subtype of metabolic associated fatty liver disease (MAFLD) remains unclear. We aimed to characterize the lipid profiles associated with liver fat content (LFC) in MAFLD patients who were overweight, lean/normal weight, or had diabetes.

METHODS

We conducted a cross-sectional study enrolling 1,182 consecutive participants (144 non-MAFLD and 1,038 MAFLD) who underwent MRI proton density fat fraction measurement (MRI-PDFF) from 2011 to 2020. Lipid and apolipoprotein profiles, free fatty acid (FFA), liver and metabolism parameters, and anthropometric measurements were also assessed.

RESULTS

MAFLD patients with type 2 diabetes or overweight/obesity had a higher proportion of abnormal lipid and lipoprotein profiles than those who were lean/normal weight. The degree of LFC had a positive correlation with total cholesterol, triglyceride, ApoB, and ApoE in patients with overweight/obesity and type 2 diabetes. In those with overweight/obesity, there were dose-response relationships between moderate-to-severe steatosis and total cholesterol, triglyceride, HDL-c, LDL-c, ApoB, ApoE, and Lp(a). A similar trend was observed for triglyceride in those with type 2 diabetes and for HDL-c in patients who were lean/normal weight (all p for trend <0.05). The combined model of relative lipid-related markers performed well in the prediction of moderate-to-severe steatosis (AUC: 0.762 for overweight/obesity; 0.742 for lean/normal weight).

CONCLUSION

LFC was associated with lipid profiles, including triglyceride, LDL-c, ApoB, ApoE, and FFA. These relationships were varied by the phenotype of MAFLD according to its diagnostic flow.