Correlation Between Fatty Liver and Lipidemia in Taiwanese

Impact of Inflammatory Bowel Disease (IBD) and IBD Medications on Risk of Hyperlipidemia and in vitro Hepatic Lipogenic-Related Gene Expression: A Population-Based Cohort Study

Patients with inflammatory bowel disease (IBD) present a higher risk of developing cardiovascular diseases (CVDs) due to chronic inflammation, which plays an essential role in atherogenesis. Hyperlipidemia is another risk factor for CVDs; however, the association between IBD, IBD medications, and hyperlipidemia remains controversial. We conducted a nationwide, population-based, retrospective, cohort study to examine the effect of IBD and IBD medications on the risk of developing hyperlipidemia. The effects of IBD medications on the expression of lipogenesis-related hepatic genes were also evaluated. We obtained data from the Longitudinal Health Insurance Database of Taiwan from patients with new-onset IBD and a comparison cohort of patients without IBD. A Cox proportional hazards regression model was used to analyze the difference in the risk of developing hyperlipidemia between the two cohorts. We also examined the influence of IBD medications on the expression of lipogenesis-related hepatic genes. After adjusting for comorbidities and confounding factors, the case group (N = 14,524) had a higher risk for hyperlipidemia than the control group (N = 14,524) [adjusted hazards ratio (aHR), 2.18]. Patients with IBD that did not receive IBD medications exhibited a significantly higher risk of hyperlipidemia (aHR, 2.20). In those treated with IBD medications, the risk of developing hyperlipidemia was significantly lowered than those without such medications (all aHR ≤ 0.45). Gene expression analysis indicated that IBD medications downregulated the expression of lipogenesis-related genes. Screening blood lipids in IBD patients is needed to explore the specific role and impact of IBD medications in the development of CVD.

Influences of antidepressant medications on the risk of developing hyperlipidemia in patients with depression by a population-based cohort study and on in vitro hepatic lipogenic-related gene expression

BACKGROUND

Depression increases the risk of cardiovascular disease (CVD). The association between antidepressant medications (ADMs) and CVD remains controversial. Hyperlipidemia is a risk factor for CVD. We conducted a nationwide population-based retrospective cohort study to examine depression and ADM use on the risk of developing hyperlipidemia. The effects of ADMs on the expression of lipogenesis-related hepatic genes were also evaluated.

METHODS

We obtained data from the Longitudinal Health Insurance Database of Taiwan on patients with new-onset depression and a comparison cohort without depression. A Cox proportional hazards regression model was used to analyze the differences in the risk of developing hyperlipidemia between these two cohorts. We also examined the influence of ADMs on the expression of lipogenesis-related hepatic genes.

RESULTS

After adjustment for comorbidities and confounding factors, the case group (N = 38,322) had a higher risk for hyperlipidemia than that of the control cohort (N = 38,322) [adjusted hazards ratio (aHR) =1.16]. Patients with depression who did not receive ADM therapy exhibited a significantly higher risk of hyperlipidemia (aHR = 1.61). However, in patients with depression treated with ADMs, the risk of developing hyperlipidemia was significantly lowered compared to the patients without ADMs (all aHR < 0.81). Gene expression analysis indicated that ADMs downregulated the expression of lipogenesis-related hepatic genes.

LIMITATIONS

Unmeasured confounding risk factors for hyperlipidemia might not have been included in the study.

CONCLUSIONS

ADMs reduced hyperlipidemia risk in patients with depression, partly by downregulating the expression of lipogenesis-related genes and improving the patients' lipid profiles. Early diagnosis and management of hyperlipidemia would further facilitate the prevention of CVD.

Effects of Urate-Lowering Therapy on Risk of Hyperlipidemia in Gout by a Population-Based Cohort Study and on In Vitro Hepatic Lipogenesis-Related Gene Expression

Patients with gout are at a higher risk of cardiovascular disease, which is associated with hyperlipidemia. Management of gout in Taiwan is poor, and the association between urate-lowering therapy (ULT) among gout patients and hyperlipidemia is unclear. We conducted a retrospective cohort study using data from the Longitudinal Health Insurance Database (LHID) of Taiwan on new-onset gout patients and a comparison cohort without gout. A Cox proportional hazards model was used to analyze differences in the risk of hyperlipidemia between patients with and without gout after considering related comorbidities. We also examined the ULT medications on the hepatic expression of lipogenesis-related genes. After adjusting for potential confounders, the case group (44,413 patients) was found to have a higher risk of hyperlipidemia than the control cohort (177,652 patients) [adjusted hazards ratio (aHR) = 2.55]. Gout patients without antigout treatment had significantly higher risk of hyperlipidemia than the control cohort (aHR = 3.10). Among gout patients receiving ULT, except those receiving probenecid (aHR = 0.80), all had significantly lower risk of hyperlipidemia than gout patients without ULT (all aHR < 0.90). Using real-time polymerase chain reaction, we found that most of the antigout drugs decreased the expression of hepatic genes related to lipogenesis in differentiated HepaRG cells. These data indicate that these antigout drugs reduce hyperlipidemia in gout patients, partly via the reduction in expression of lipogenesis-related genes, leading to improved blood lipid profiles. We provide evidence of the strong association between gout and hyperlipidemia and highlight the need for appropriate treatment guidelines.

A Population-Based Cohort Study on the Association of Hyperthyroidism With the Risk of Hyperlipidemia and the Effects of Anti-thyroid Drugs on Hepatic Gene Expression

There have been no reports on the association of hyperthyroidism with hyperlipidemia in patients undergoing treatment especially in Asia. To determine the association between hyperthyroidism and the risk of hyperlipidemia in patients, we conducted a retrospective cohort study using Longitudinal Health Insurance Database (LHID) from Taiwan, R.O.C. We also evaluate the influence of 6-n-propyl-2-thiouracil (PTU) and methimazole (MMI) on hepatic genes to explain changes in blood lipid levels in a hepatic cell line model. The cohort study involved 13,667 patients with hyperthyroidism, and the corresponding comparison cohort had four times as many patients. Using Kaplan-Meier analysis method, the results showed that, compared to patients without hyperthyroidism, the overall incidence of hyperlipidemia was significantly higher in the hyperthyroidism patients (18.7 vs. 11.8 cases/1,000 persons-years; adjusted HR 1.5; 95% CI, 1.41–1.59). With only PTU or MMI/carbimazole (CBM) treatment, patients with hyperthyroidism showed a 1.78-fold (95% CI, 1.50–2.11) and 1.43-fold (95% CI, 1.27–1.60) higher risk of hyperlipidemia than those without hyperthyroidism, respectively. Additionally, hyperthyroidism patients that received surgery only or surgery with I¹³¹ therapy tended to have a higher risk of hyperlipidemia. Although PTU and MMI treatment decreased the expression levels of genes responsible for circulating remnant lipoproteins, they increased the levels of lipogenic gene expression in hepatic cells. Thus, treatment of hyperthyroid patients with anti-thyroid drugs (ATDs), I¹³¹, or surgery is likely to induce hyperlipidemia. ATDs downregulate the expression of genes involved in lipoproteins clearance; increases lipogenic genes expression, which may partly contribute to abnormal blood lipid profiles.

Sesamin, a Naturally Occurring Lignan, Inhibits Ligand-Induced Lipogenesis through Interaction with Liver X Receptor Alpha (LXRα) and Pregnane X Receptor (PXR)

Liver X receptor (LXR) is a nuclear receptor that regulates various biological processes, including de novo lipogenesis, cholesterol metabolism, and inflammation. Selective inhibition of LXR may aid the treatment of nonalcoholic fatty liver disease (NAFLD). Sesamin is a naturally occurring lignan in many dietary plants and has a wide range of beneficial effects on metabolism. The mechanism underlying sesamin action especially on the regulation of LXR remains elusive. Reporter assays, mRNA and protein expression, and in silico modeling were used to identify sesamin as an antagonist of LXRα. Sesamin was applied to the hepatic HepaRG and intestinal LS174T cells and showed that it markedly ameliorated lipid accumulation in the HepaRG cells, by reducing LXRα transactivation, inhibiting the expression of downstream target genes. This effect was associated with the stimulation of AMP-activated protein kinase (AMPK) signaling pathway, followed by decreased T0901317-LXRα-induced expression of SREBP-1c and its downstream target genes. Mechanistically, sesamin reduced the recruitment of SRC-1 but enhanced that of SMILE to the SREBP-1c promoter region under T0901317 treatment. It regulated the transcriptional control exerted by LXRα by influencing its interaction with coregulators and thus decreased mRNA and protein levels of genes downstream of LXRα and reduced lipid accumulation in hepatic cells. Additionally, sesamin reduced valproate- and rifampin-induced LXRα and pregnane X receptor (PXR) transactivation. This was associated with reduced expression of target genes and decreased lipid accumulation. Thus, sesamin is an antagonist of LXRα and PXR and suggests that it may alleviate drug-induced lipogenesis via the suppression of LXRα and PXR signaling.

Ursolic Acid, a Novel Liver X Receptor α (LXRα) Antagonist Inhibiting Ligand-Induced Nonalcoholic Fatty Liver and Drug-Induced Lipogenesis

Nonalcoholic fatty liver disease (NAFLD) is a very common liver disease, and its incidence has significantly increased worldwide. The liver X receptor α (LXRα) is a multifunctional nuclear receptor that controls lipid homeostasis. Inhibition of LXRα transactivation may be beneficial for NAFLD and hyperlipidemia treatment. Ursolic acid (UA) is a plant triterpenoid with many beneficial effects; however, the mechanism of its action on LXRα remains elusive. We evaluated the effects of UA on T0901317 (T090)-induced LXRα activation and steatosis. UA significantly decreased the LXR response element and sterol regulatory element-binding protein-1c ( SREBP-1c) gene promoter activities, mRNA, protein expression of LXRα target genes, and hepatic cellular lipid content in a T090-induced mouse model. A molecular docking study indicated that UA bound competitively with T090 at the LXRα ligand binding domain. UA stimulated AMP-activated protein kinase (AMPK) phosphorylation in hepatic cells and increased corepressor, small heterodimer partner-interacting leucine zipper protein (SMILE) but decreased coactivator, steroid receptor coactivator-1 (SRC-1) recruitment to the SREBP-1c promoter region. In contrast, UA induced SRC-1 binding but decreased SMILE binding to reverse cholesterol transport-related gene promoters in intestinal cells, increasing lipid excretion from intestinal cells. Additionally, UA reduced valproate-induced LXRα mediated and rifampin-induced pregnane X receptor mediated lipogenesis, offering potential treatments for drug-induced hepatic steatosis. Thus, UA displays liver specificity and can be selectively repressed while RCT stimulation by LXRα is preserved and enhanced. This is a novel therapeutic option to treat NAFLD and may be helpful in developing LXR agonists to prevent atherosclerosis.

Oleanolic Acid Inhibits Liver X Receptor Alpha and Pregnane X Receptor to Attenuate Ligand-Induced Lipogenesis

Liver X receptor α (LXRα) controls important biological and pathophysiological processes such as lipid homeostasis. Inhibiting LXRα transactivation may beneficial in the treatment of nonalcoholic fatty liver disease (NAFLD), which is one of the main causes of liver diseases and hyperlipidemia. Oleanolic acid (OA) is a naturally occurring triterpenoid found in many plants. It has several beneficial effects on biological pathways; however, the mechanisms underlying its effects on LXRα are unclear. Therefore, we evaluated the effects of OA on T0901317-induced LXRα activation and explored whether OA can attenuate hepatic lipogenesis. The results showed that OA significantly decreased the promoter activities of LXR response element and sterol regulatory element binding protein-1c (SREBP-1c). It also decreased the mRNA and protein expression of LXRα target genes. These resulted in reduced hepatocellular lipid content. Our results also revealed that the overall binding pose of OA is similar to the X-ray pose of T0901317. Furthermore, OA stimulated AMP-activated protein kinase phosphorylation in hepatic cells. Additionally, it increased small heterodimer partner-interacting leucine zipper protein (SMILE) but decreased steroid receptor coactivator-1 (SRC-1) recruitment to the SREBP-1c promoter region. OA also enhanced LXRα-mediated induction of reverse cholesterol transport (RCT)-related gene, ATP-binding cassette transporter (ABC) A1, and ABCG1 expression in intestinal cells. It was found that OA increased the binding of SRC-1 but decreased SMILE recruitment to the ABCG1 gene promoter region. Furthermore, it reduced valproate- and rifampin-induced LXRα- and pregnane X receptor-mediated lipogenesis, respectively, which indicates its potential benefit in treating drug-induced hepatic steatosis. The results also show that OA is liver-specific and can be selectively repressed of lipogenesis. Moreover, it preserves and enhances LXRα-induced RCT stimulation. The results show that OA may be a promising treatment for NAFLD. Additionally, it can be used in the development of LXRα agonists to prevent atherosclerosis.