Capparis spinosa improves non-alcoholic steatohepatitis through down-regulating SREBP-1c and a PPARα-independent pathway in high-fat diet-fed rats

Triglycerides: A Sensitizer but Not a Trigger for Hypertriglyceridemic Acute Pancreatitis

BACKGROUND

The incidence of hypertriglyceridemic acute pancreatitis (HTG-AP) is increasing. Although the guideline defines the diagnostic criteria as triglyceride (TG) greater than 11.3 mmol/L, there is actually no specific threshold. Many people with hypertriglyceridemia (HTG) or obvious chyloid blood do not develop acute pancreatitis (AP).

AIMS

To explore the role of HTG in the pathogenesis of AP.

METHODS

Thirty-six male SD rats were randomly assigned into normal control, AP, HTG, HTG-AP, low-dose fenofibrate and high-dose fenofibrate groups. Serum indices and cytokine levels in serum, and pathological changes in pancreatic tissues were observed. The expression levels of TLR4 and NF-κBp65 in pancreatic tissues were detected by immunohistochemistry and Western blot.

RESULTS

In normal rats, HTG alone did not induce AP. However, after establishing the HTG-AP model with Poloxam 407 and L-arginine, serum-free fatty acid and TG levels were positively correlated with the levels of lipase, amylase, IL-1β, IL-6, pancreatic inflammation scores, and the expressions of TLR4 and NF-κBp65 (all P < 0.001). Expressions of TLR4 and NF-κBp65 were significantly increased in the pancreatic tissues of HTG-AP rats. Fenofibrate effectively decreased TG levels in HTG-AP rats and reduced the expression of TLR4 and NF-κBp65 (all P < 0.001).

CONCLUSIONS

HTG does not directly cause AP, but rather increases the susceptibility to AP or aggravates the inflammatory response. It is more like a sensitizer of inflammation rather than an activator.

Examining the Pathogenesis of MAFLD and the Medicinal Properties of Natural Products from a Metabolic Perspective

Metabolic-associated fatty liver disease (MAFLD), characterized primarily by hepatic steatosis, has become the most prevalent liver disease worldwide, affecting approximately two-fifths of the global population. The pathogenesis of MAFLD is extremely complex, and to date, there are no approved therapeutic drugs for clinical use. Considerable evidence indicates that various metabolic disorders play a pivotal role in the progression of MAFLD, including lipids, carbohydrates, amino acids, and micronutrients. In recent years, the medicinal properties of natural products have attracted widespread attention, and numerous studies have reported their efficacy in ameliorating metabolic disorders and subsequently alleviating MAFLD. This review aims to summarize the metabolic-associated pathological mechanisms of MAFLD, as well as the natural products that regulate metabolic pathways to alleviate MAFLD.

The Role of SCAP/SREBP as Central Regulators of Lipid Metabolism in Hepatic Steatosis

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is rapidly increasing worldwide at an alarming pace, due to an increase in obesity, sedentary and unhealthy lifestyles, and unbalanced dietary habits. MASLD is a unique, multi-factorial condition with several phases of progression including steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Sterol element binding protein 1c (SREBP1c) is the main transcription factor involved in regulating hepatic de novo lipogenesis. This transcription factor is synthesized as an inactive precursor, and its proteolytic maturation is initiated in the membrane of the endoplasmic reticulum upon stimulation by insulin. SREBP cleavage activating protein (SCAP) is required as a chaperon protein to escort SREBP from the endoplasmic reticulum and to facilitate the proteolytic release of the N-terminal domain of SREBP into the Golgi. SCAP inhibition prevents activation of SREBP and inhibits the expression of genes involved in triglyceride and fatty acid synthesis, resulting in the inhibition of de novo lipogenesis. In line, previous studies have shown that SCAP inhibition can resolve hepatic steatosis in animal models and intensive research is going on to understand the effects of SCAP in the pathogenesis of human disease. This review focuses on the versatile roles of SCAP/SREBP regulation in de novo lipogenesis and the structure and molecular features of SCAP/SREBP in the progression of hepatic steatosis. In addition, recent studies that attempt to target the SCAP/SREBP axis as a therapeutic option to interfere with MASLD are discussed.