desmosterol and Inflammation

High-risk subjects with elevated C-reactive protein (CRP) are at high risk for cardiovascular events and frequently require potent statins or combined lipid-lowering therapy to achieve lipid targets and decrease inflammation. Our study aimed at evaluating the effects of three lipid-modifying therapies on LDL-cholesterol, CRP levels and markers of cholesterol absorption and synthesis.. A prospective intervention study was performed in high cardiovascular risk individuals receiving atorvastatin 10mg daily for four weeks. Those with CRP≥2.0mg/L were randomized to another four-week treatment period with atorvastatin 40mg, ezetimibe 10mg or the combination of atorvastatin 40mg / ezetimibe 10mg. Lipids, markers of cholesterol absorption (campesterol and β-sitosterol), and synthesis (desmosterol), as well as CRP were quantified at baseline and end of study.. One hundred and twenty two individuals were included. Atorvastatin alone or combined with ezetimibe reduced both LDL-cholesterol and CRP (P<0.002 vs. baseline; Wilcoxon); ezetimibe did not modify CRP. Ezetimibe-based therapies reduced absorption markers and their ratios to cholesterol (P<0.0001 vs. baseline, for all; Wilcoxon), whereas atorvastatin alone increased campesterol/cholesterol and β-sitosterol/cholesterol ratios (P<0.05 vs. baseline; Wilcoxon). In addition, ezetimibe also increased desmosterol and desmosterol/cholesterol ratio (P<0.0001 vs. baseline; Wilcoxon).. These results contribute to understanding the link between cellular cholesterol homeostasis, inflammation and lipid-modifying therapies. Our findings highlight the broader benefit of combined therapy with a potent statin and ezetimibe decreasing inflammation, and preventing increase in cholesterol biosynthesis, an effect not observed with ezetimibe alone.

Topics: Aged; Anticholesteremic Agents; Atorvastatin; Azetidines; C-Reactive Protein; Cardiovascular Diseases; Cholesterol; Desmosterol; Ezetimibe; Female; Heptanoic Acids; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inflammation; Male; Middle Aged; Phytosterols; Prospective Studies; Pyrroles; Risk Factors; Sitosterols; Statistics, Nonparametric

Liver X receptor (LXR) agonism has theoretical potential for treating NAFLD/NASH, but synthetic agonists induce hyperlipidemia in preclinical models. Desmosterol, which is converted by Δ24-dehydrocholesterol reductase (DHCR24) into cholesterol, is a potent endogenous LXR agonist with anti-inflammatory properties. We aimed to investigate the effects of DHCR24 inhibition on NAFLD/NASH development. Here, by using APOE*3-Leiden. CETP mice, a well-established translational model that develops diet-induced human-like NAFLD/NASH characteristics, we report that SH42, a published DHCR24 inhibitor, markedly increases desmosterol levels in liver and plasma, reduces hepatic lipid content and the steatosis score, and decreases plasma fatty acid and cholesteryl ester concentrations. Flow cytometry showed that SH42 decreases liver inflammation by preventing Kupffer cell activation and monocyte infiltration. LXRα deficiency completely abolishes these beneficial effects of SH42. Together, the inhibition of DHCR24 by SH42 prevents diet-induced hepatic steatosis and inflammation in a strictly LXRα-dependent manner without causing hyperlipidemia. Finally, we also showed that SH42 treatment decreased liver collagen content and plasma alanine transaminase levels in an established NAFLD model. In conclusion, we anticipate that pharmacological DHCR24 inhibition may represent a novel therapeutic strategy for treatment of NAFLD/NASH.

Topics: Animals; Desmosterol; Humans; Inflammation; Liver; Mice; Mice, Inbred C57BL; Nerve Tissue Proteins; Non-alcoholic Fatty Liver Disease; Oxidoreductases; Oxidoreductases Acting on CH-CH Group Donors

Topics: Animals; Atherosclerosis; Cholesterol; Coronary Vessels; Desmosterol; Foam Cells; Humans; Inflammasomes; Inflammation; Lipid Metabolism; Liver X Receptors; Macrophage Activation; Macrophages; Male; Mice; Nerve Tissue Proteins; Oxidoreductases Acting on CH-CH Group Donors; Plaque, Atherosclerotic; Sterols

The repair of inflamed, demyelinated lesions as in multiple sclerosis (MS) necessitates the clearance of cholesterol-rich myelin debris by microglia/macrophages and the switch from a pro-inflammatory to an anti-inflammatory lesion environment. Subsequently, oligodendrocytes increase cholesterol levels as a prerequisite for synthesizing new myelin membranes. We hypothesized that lesion resolution is regulated by the fate of cholesterol from damaged myelin and oligodendroglial sterol synthesis. By integrating gene expression profiling, genetics and comprehensive phenotyping, we found that, paradoxically, sterol synthesis in myelin-phagocytosing microglia/macrophages determines the repair of acutely demyelinated lesions. Rather than producing cholesterol, microglia/macrophages synthesized desmosterol, the immediate cholesterol precursor. Desmosterol activated liver X receptor (LXR) signaling to resolve inflammation, creating a permissive environment for oligodendrocyte differentiation. Moreover, LXR target gene products facilitated the efflux of lipid and cholesterol from lipid-laden microglia/macrophages to support remyelination by oligodendrocytes. Consequently, pharmacological stimulation of sterol synthesis boosted the repair of demyelinated lesions, suggesting novel therapeutic strategies for myelin repair in MS.

Topics: Animals; Cholesterol; Demyelinating Diseases; Desmosterol; Encephalomyelitis, Autoimmune, Experimental; Female; Gene Expression Profiling; Humans; Inflammation; Lipid Metabolism; Liver X Receptors; Mice; Mice, Inbred C57BL; Microglia; Middle Aged; Multiple Sclerosis; Oligodendroglia; Phagocytosis; Squalene; Sterols

The inflammatory component of non-alcoholic steatohepatitis (NASH) can lead to irreversible liver damage. Therefore there is an urgent need to identify novel interventions to combat hepatic inflammation. In mice, omitting cholesterol from the diet reduced hepatic inflammation. Considering the effects of plant sterol/stanol esters on cholesterol metabolism, we hypothesized that plant sterol/stanol esters reduces hepatic inflammation. Indeed, adding plant sterol/stanol esters to a high-fat-diet reduced hepatic inflammation as indicated by immunohistochemical stainings and gene expression for inflammatory markers. Finally, adding sterol/stanol esters lowered hepatic concentrations of cholesterol precursors lathosterol and desmosterol in mice, which were highly elevated in the HFD group similarly as observed in severely obese patients with NASH. In vitro, in isolated LPS stimulated bone marrow derived macrophages desmosterol activated cholesterol efflux whereas sitostanol reduced inflammation. This highly interesting observation that plant sterol/stanol ester consumption leads to complete inhibition of HFD-induced liver inflammation opens new venues in the treatment and prevention of hepatic inflammation.

Topics: Animals; Cholesterol; Desmosterol; Dietary Fats; Female; Humans; Inflammation; Liver; Macrophages; Mice; Mice, Knockout; Non-alcoholic Fatty Liver Disease; Phytosterols