Liproxstatin-1 attenuates acute hypertriglyceridemic pancreatitis through inhibiting ferroptosis in rats.

Ferroptosis is closely associated with inflammatory diseases, including acute pancreatitis (AP); however, the involvement of ferroptosis in hypertriglyceridemic pancreatitis (HTGP) remains unclear. In the present study, we aimed to explore the relationship between lipid metabolism and ferroptosis in HTGP and the alleviating effect of liproxstatin-1 (Lip-1) in vivo. This study represents the first exploration of lipid metabolism and endoplasmic reticulum stress (ERS) in HTGP, targeting ferroptosis as a key factor in HTGP. Hypertriglyceridemia (HTG) was induced under high-fat diet conditions. Cerulein was then injected to establish AP and HTGP models. Lip-1, a specific ferroptosis inhibitor, was administered before the induction of AP and HTGP in rats, respectively. Serum triglyceride, amylase, inflammatory factors, pathological and ultrastructural structures, lipid peroxidation, and iron overload indicators related to ferroptosis were tested. Moreover, the interaction between ferroptosis and ERS was assessed. We found HTG can exacerbate the development of AP, with an increased inflammatory response and intensified ferroptosis process. Lip-1 treatment can attenuate pancreatic injury by inhibiting ferroptosis through lipid metabolism and further resisting activations of ERS-related proteins. Totally, our results proved lipid metabolism can promote ferroptosis in HTGP by regulating ACSL4/LPCAT3 protein levels. Additionally, ERS may participate in ferroptosis via the Bip/p-EIF2α/CHOP pathway, followed by the alleviating effect of Lip-1 in the rat model.

ANGPTL3 and ApoC-III inhibitors for treating hypertriglyceridemia in context: horses for courses?

PURPOSE OF REVIEW: Hypertriglyceridemia (HTG) is an independent and casual risk factor for atherosclerotic cardiovascular disease (ASCVD). There is an unmet need for more effective treatments for patients with HTG. Angiopoietin-like protein 3 (ANGPTL3) and apolipoprotein C-III (apoC-III) are key regulators of triglyceride-rich lipoprotein (TRL) metabolism. We review recent clinical trials targeting ANGPTL3 and apoC-III with monoclonal antibody and nucleic acid therapies, including antisense oligonucleotides and small interfering RNA. RECENT FINDINGS: ANGPTL3 and apoC-III inhibitors are effective in lowering plasma triglycerides and TRLs, with possibly greater efficacy with the inhibition of apoC-III. By contrast to ANGPTL3 inhibition that has the advantage of greater lowering of plasma low-density lipoprotein (LDL)-cholesterol and apoB levels, apoC-III inhibition only has a modest or no effect in lowering plasma LDL-cholesterol and apoB concentrations. Therapeutic inhibition of ANGPTL3 and apoC-III can correct HTG possibly by reducing production and increasing catabolism of TRL particles, but this remains to be formally investigated in patients with HTG. SUMMARY: Novel agents targeting ANGPTL3 and apoC-III can correct HTG and potentially lower risk of ASCVD in patients with HTG. The long-term safety and cost-effectiveness of these agents await confirmation in ongoing and future studies.

The Role of Triglycerides in Atherosclerosis: Recent Pathophysiologic Insights and Therapeutic Implications.

Triglycerides have long been recognized as a cardiovascular disease risk factor. However, their precise role in atherosclerosis and potential utility as a therapeutic target remains debated topics. This review aims to shed light on these aspects by exploring the complex relationship between triglycerides and atherosclerosis from pathophysiological and pharmacological perspectives. Triglycerides, primarily carried by chylomicrons and very low-density lipoproteins, play an essential role in energy storage and utilization. Dysregulation of triglyceride homeostasis and triglyceride- rich lipoproteins metabolism often leads to hypertriglyceridemia and subsequently increases atherosclerosis risk. Triglyceride-rich lipoproteins remnants interact with arterial wall endothelial cells, get retained in the subendothelial space, and elicit inflammatory responses, thereby accelerating atherogenesis. Despite the clear association between high triglyceride levels and increased cardiovascular disease risk, intervention trials targeting triglyceride reduction have produced mixed results. We discuss a range of triglyceride-lowering agents, from fibrates to omega-3 fatty acids, with a focus on their mechanism of action, efficacy, and major clinical trial outcomes. Notably, the role of newer agents, such as angiopoietin-like protein 3 and apolipoprotein C3 inhibitors, is also explored. We highlight the challenges and controversies, including the ongoing debate on the causal role of triglyceride in atherosclerosis and the discordant outcomes of recent clinical trials. The potential confounding effects of associated risk factors, such as elevated apolipoprotein B, insulin resistance, and metabolic syndrome, are considered. In conclusion, this review underscores the importance of a nuanced approach to understanding the role of triglycerides in atherosclerosis and their potential as a therapeutic target. Further research is needed to unravel the complex interplay between triglycerides, triglyceride-rich lipoproteins, and associated factors in atherosclerosis pathogenesis and refine triglyceride-targeted therapeutic strategies.

A Very-Low-Calorie Diet Can Cause Remission of Diabetes Mellitus and Hypertriglyceridemia in Familial Partial Lipodystrophy.

There is no strong evidence that any specific diet is the preferred treatment for lipodystrophy syndromes. Here we remark on the benefits of a very-low-calorie diet (VLCD) in a patient with familial partial lipodystrophy type 2 (FPLD2). A 38-year-old female diagnosed with FPLD2, with a history of multiple comorbidities, underwent 16 weeks of VLCD with a short-term goal of improving her metabolic state rapidly to achieve pregnancy by in vitro fertilization (IVF). We observed a reduction of 12.3 kg in body weight and 1.4% in hemoglobin A1c. The decrease in the area under the curves of insulin (-33.2%), triglycerides (-40.7%), and free fatty acids (-34%) were very remarkable. Total body fat was reduced by 16%, and liver fat by 80%. Her egg retrieval rate and quality during IVF were far superior to past hyperstimulation. Our data encourage the use of this medical approach for other patients with similar metabolic and reproductive abnormalities due to adipose tissue insufficiency.

Inhibition of Angiopoietin-Like Protein 3 or 3/8 Complex and ApoC-III in Severe Hypertriglyceridemia.

PURPOSE OF REVIEW: The role of the inhibition of ANGPTL3 in severe or refractory hypercholesterolemia is well documented, less in severe hyperTG. This review focuses on the preclinical and clinical development of ApoC-III inhibitors and ANGPTL3, 4, and 3/8 complex inhibitors for the treatment of severe or refractory forms of hypertriglyceridemia to prevent cardiovascular disease or other morbidities. RECENT FINDINGS: APOC3 and ANGPTL3 became targets for drug development following the identification of naturally occurring loss of function variants in families with a favorable lipid profile and low cardiovascular risk. The inhibition of ANGPTL3 covers a broad spectrum of lipid disorders from severe hypercholesterolemia to severe hypertriglyceridemia, while the inhibition of ApoC-III can treat hypertriglyceridemia regardless of the severity. Preclinical and clinical data suggest that ApoC-III inhibitors, ANGPTL3 inhibitors, and inhibitors of the ANGPTL3/8 complex that is formed postprandially are highly effective for the treatment of severe or refractory hypertriglyceridemia. Inhibition of ANGPTL3 or the ANGPTL3/8 complex upregulates LPL and facilitates the hydrolysis and clearance of triglyceride-rich lipoproteins (TRL) (LPL-dependent mechanisms), whereas ApoC-III inhibitors contribute to the management and clearance of TRL through both LPL-dependent and LPL-independent mechanisms making it possible to successfully lower TG in subjects completely lacking LPL (familial chylomicronemia syndrome). Most of these agents are biologicals including monoclonal antibodies (mAb), antisense nucleotides (ASO), small interfering RNA (siRNA), or CRISPR-cas gene editing strategies.

[The role of apolipoprotein C3 in the regulation of nonalcoholic fatty liver disease, glucose and lipid metabolism, and islet ß cell function].

As a member of the apolipoprotein C (ApoC) family with a relatively high content, ApoC3 plays a major role in the regulation of triglyceride metabolism, and plays an important role in the occurrence and development of cardiovascular diseases, glucose and lipid metabolism disorders. Nonalcoholic fatty liver disease (NAFLD) refers to the accumulation of a large amount of fat in the liver in the absence of a history of chronic alcohol consumption or other damage to the liver. A large number of previous studies have shown that there is a correlation between the gene polymorphism and high expression of ApoC3 and NAFLD. In the context of hypertriglyceridemia (HTG), this article reviews the relationship between ApoC3 and NAFLD, glucose and lipid metabolism, and islet ß cell function, showing that ApoC3 can not only inhibit lipoprotein lipase (LPL) and hepatic lipase (HL) activity, delay the decomposition of triglyceride in plasma to maintain the body's energy metabolism during fasting, but also be significantly increased under insulin resistance, prompting the liver to secrete a large amount of very low-density lipoprotein (VLDL) to induce HTG. Therefore, targeting and inhibiting ApoC3 might become a new approach to treat HTG. Increasing evidence suggests that ApoC3 does not appear to be an independent "contributor" to NAFLD. Similarly, our previous studies have shown that ApoC3 is not an independent factor triggering islet ß cell dysfunction in ApoC3 transgenic mice, but in a state of excess nutrition, HTG triggered by ApoC3 high expression may exacerbate the effects of hyperglycemia and insulin resistance on islet ß cell function, and the underlying mechanism remains to be further discussed.

Hypertriglyceridemia in Apoa5-/- mice results from reduced amounts of lipoprotein lipase in the capillary lumen.

Why apolipoprotein AV (APOA5) deficiency causes hypertriglyceridemia has remained unclear, but we have suspected that the underlying cause is reduced amounts of lipoprotein lipase (LPL) in capillaries. By routine immunohistochemistry, we observed reduced LPL staining of heart and brown adipose tissue (BAT) capillaries in Apoa5-/- mice. Also, after an intravenous injection of LPL-, CD31-, and GPIHBP1-specific mAbs, the binding of LPL Abs to heart and BAT capillaries (relative to CD31 or GPIHBP1 Abs) was reduced in Apoa5-/- mice. LPL levels in the postheparin plasma were also lower in Apoa5-/- mice. We suspected that a recent biochemical observation - that APOA5 binds to the ANGPTL3/8 complex and suppresses its capacity to inhibit LPL catalytic activity - could be related to the low intracapillary LPL levels in Apoa5-/- mice. We showed that an ANGPTL3/8-specific mAb (IBA490) and APOA5 normalized plasma triglyceride (TG) levels and intracapillary LPL levels in Apoa5-/- mice. We also showed that ANGPTL3/8 detached LPL from heparan sulfate proteoglycans and GPIHBP1 on the surface of cells and that the LPL detachment was blocked by IBA490 and APOA5. Our studies explain the hypertriglyceridemia in Apoa5-/- mice and further illuminate the molecular mechanisms that regulate plasma TG metabolism.

Differential effects on renal function and glucose metabolism of renal dependent bezafibrate and non-renal dependent pemafibrate in patients with hypertriglyceridemia.

OBJECTIVE: Among fibrates as triglyceride-lowering agents, bezafibrate and fenofibrate are predominantly renally excreted, while pemafibrate is mainly hepatically metabolized and biliary excreted. To elucidate possible different properties among fibrates, this retrospective observational study examined the changes in clinical laboratory parameters, including indices of renal function and glucose metabolism, in cases of switching from bezafibrate to pemafibrate. MATERIALS AND METHODS: In 93 patients with hypertriglyceridemia, the average values of laboratory parameters including serum creatinine, estimated glomerular filtration rate (eGFR), plasma glucose, and hemoglobin A1c on respective two occasions before and after switching from bezafibrate to pemafibrate were evaluated. RESULTS: Triglycerides, low-density and high-density lipoprotein cholesterol, creatine kinase, and uric acid did not change before and after switching from bezafibrate to pemafibrate. Serum creatinine significantly decreased and eGFR significantly increased after switching from bezafibrate to pemafibrate (p < 0.001, respectively). Plasma glucose tended to increase (p = 0.070) and hemoglobin A1c significantly increased (p < 0.001) after switching to pemafibrate. The degrees of changes in creatinine, eGFR, glucose, and hemoglobin A1c before and after drug switching were not affected by the presence or absence of coexisting disease, and with or without drug treatment including statin and renin-angiotensin system inhibitor. CONCLUSION: Our findings indicate that switching from bezafibrate to pemafibrate produces a significant decrease in serum creatinine and increases in eGFR and hemoglobin A1c in patients with hypertriglyceridemia, suggesting that the effects on renal function and glucose metabolism differ among fibrates.

Role of glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 in hypertriglyceridemia and diabetes.

In diabetes, the impairment of insulin secretion and insulin resistance contribute to hypertriglyceridemia, as the enzymatic activity of lipoprotein lipase (LPL) depends on insulin action. The transport of LPL to endothelial cells and its enzymatic activity are maintained by the formation of lipolytic complex depending on the multiple positive (glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 [GPIHBP1], apolipoprotein C-II [APOC2], APOA5, heparan sulfate proteoglycan [HSPG], lipase maturation factor 1 [LFM1] and sel-1 suppressor of lin-12-like [SEL1L]) and negative regulators (APOC1, APOC3, angiopoietin-like proteins [ANGPTL]3, ANGPTL4 and ANGPTL8). Among the regulators, GPIHBP1 is a crucial molecule for the translocation of LPL from parenchymal cells to the luminal surface of capillary endothelial cells, and maintenance of lipolytic activity; that is, hydrolyzation of triglyceride into free fatty acids and monoglyceride, and conversion from chylomicron to chylomicron remnant in the exogenous pathway and from very low-density lipoprotein to low-density lipoprotein in the endogenous pathway. The null mutation of GPIHBP1 causes severe hypertriglyceridemia and pancreatitis, and GPIGBP1 autoantibody syndrome also causes severe hypertriglyceridemia and recurrent episodes of acute pancreatitis. In patients with type 2 diabetes, the elevated serum triglyceride levels negatively correlate with circulating LPL levels, and positively with circulating APOC1, APOC3, ANGPTL3, ANGPTL4 and ANGPTL8 levels. In contrast, circulating GPIHBP1 levels are not altered in type 2 diabetes patients with higher serum triglyceride levels, whereas they are elevated in type 2 diabetes patients with diabetic retinopathy and nephropathy. The circulating regulators of lipolytic complex might be new biomarkers for lipid and glucose metabolism, and diabetic vascular complications.

Hepatic mTORC2 compensates for loss of adipose mTORC2 in mediating energy storage and glucose homeostasis.

Mammalian target of rapamycin complex 2 (mTORC2) is a protein kinase complex that plays an important role in energy homeostasis. Loss of adipose mTORC2 reduces lipogenic enzyme expression and de novo lipogenesis in adipose tissue. Adipose-specific mTORC2 knockout mice also display triglyceride accumulation in the liver. However, the mechanism and physiological role of hepatic triglyceride accumulation upon loss of adipose mTORC2 are unknown. Here, we show that loss of adipose mTORC2 increases the expression of de novo lipogenic enzymes in the liver, thereby causing accumulation of hepatic triglyceride and hypertriglyceridemia. Simultaneous inhibition of lipogenic enzymes in adipose tissue and liver by ablating mTORC2 in both tissues prevented accumulation of hepatic triglycerides and hypertriglyceridemia. However, loss of adipose and hepatic mTORC2 caused severe insulin resistance and glucose intolerance. Thus our findings suggest that increased hepatic lipogenesis is a compensatory mechanism to cope with loss of lipogenesis in adipose tissue, and further suggest that mTORC2 in adipose tissue and liver plays a crucial role in maintaining whole body energy homeostasis.NEW & NOTEWORTHY Loss of adipose and hepatic mTORC2 causes diabetes.

Strawberry, Blueberry, and Strawberry-Blueberry Blend Beverages Prevent Hepatic Steatosis in Obese Rats by Modulating Key Genes Involved in Lipid Metabolism.

There is an increasing interest in developing natural herb-infused functional beverages with health benefits; therefore, in this study, we aimed to evaluate the effect of strawberry, blueberry, and strawberry-blueberry blend decoction-based functional beverages on obesity-related metabolic alterations in high-fat and high-fructose diet-fed rats. The administration of the three berry-based beverages for eighteen weeks prevented the development of hypertriglyceridemia in obese rats (1.29-1.78-fold) and hepatic triglyceride accumulation (1.38-1.61-fold), preventing the development of hepatic steatosis. Furthermore, all beverages significantly down-regulated Fasn hepatic expression, whereas the strawberry beverage showed the greatest down-regulation of Acaca, involved in fatty acid de novo synthesis. Moreover, the strawberry beverage showed the most significant up-regulation of hepatic Cpt1 and Acadm (fatty acid ß-oxidation). In contrast, the blueberry beverage showed the most significant down-regulation of hepatic Fatp5 and Cd36 (fatty acid intracellular transport). Nevertheless, no beneficial effect was observed on biometric measurements, adipose tissue composition, and insulin resistance. On the other hand, several urolithins and their derivatives, and other urinary polyphenol metabolites were identified after the strawberry-based beverages supplementation. In contrast, enterolactone was found significantly increase after the intake of blueberry-based beverages. These results demonstrate that functional beverages elaborated with berry fruits prevent diet-induced hypertriglyceridemia and hepatic steatosis by modulating critical genes involved in fatty acid hepatic metabolism.

The Association between the Differential Expression of lncRNA and Type 2 Diabetes Mellitus in People with Hypertriglyceridemia.

Compared with diabetic patients with normal blood lipid, diabetic patients with dyslipidemia such as high triglycerides have a higher risk of clinical complications, and the disease is also more serious. For the subjects with hypertriglyceridemia, the lncRNAs affecting type 2 diabetes mellitus (T2DM) and the specific mechanisms remain unclear. Transcriptome sequencing was performed on peripheral blood samples of new-onset T2DM (six subjects) and normal blood control (six subjects) in hypertriglyceridemia patients using gene chip technology, and differentially expressed lncRNA profiles were constructed. Validated by the GEO database and RT-qPCR, lncRNA ENST00000462455.1 was selected. Subsequently, fluorescence in situ hybridization (FISH), real-time quantitative polymerase chain reaction (RT-qPCR), CCK-8 assay, flow cytometry, and enzyme-linked immunosorbent assay (ELISA) were used to observe the effect of ENST00000462455.1 on MIN6. When silencing the ENST00000462455.1 for MIN6 in high glucose and high fat, the relative cell survival rate and insulin secretion decreased, the apoptosis rate increased, and the expression of the transcription factors Ins1, Pdx-1, Glut2, FoxO1, and ETS1 that maintained the function and activity of pancreatic ß cells decreased (p < 0.05). In addition, we found that ENST00000462455.1/miR-204-3p/CACNA1C could be the core regulatory axis by using bioinformatics methods. Therefore, ENST00000462455.1 was a potential biomarker for hypertriglyceridemia patients with T2DM.

APOC-III: a Gatekeeper in Controlling Triglyceride Metabolism.

PURPOSE OF REVIEW: Apolipoprotein C-III (ApoC-III) is a widely known player in triglyceride metabolism, and it has been recently recognized as a polyhedric factor which may regulate several pathways beyond lipid metabolism by influencing cardiovascular, metabolic, and neurological disease risk. This review summarizes the different functions of ApoC-III and underlines the recent findings related to its multifaceted pathophysiological role. RECENT FINDINGS: The role of ApoC-III has been implicated in HDL metabolism and in the development of atherosclerosis, inflammation, and ER stress in endothelial cells. ApoC-III has been recently considered an important player in insulin resistance mechanisms, lipodystrophy, diabetic dyslipidemia, and postprandial hypertriglyceridemia (PPT). The emerging evidence of the involvement of ApoC-III in the in the pathogenesis of Alzheimer's disease open the way to further study if modification of ApoC-III level slows disease progression. Furthermore, ApoC-III is clearly linked to cardiovascular disease (CVD) risk, and progression of coronary artery disease (CAD) as well as the calcification of aortic valve and recent clinical trials has pointed out the inhibition of ApoC-III as a promising approach to manage hypertriglyceridemia and prevent CVD. Several evidences highlight the role of ApoC-III not only in triglyceride metabolism but also in several cardio-metabolic pathways. Results from recent clinical trials underline that the inhibition of ApoC-III is a promising therapeutical strategy for the management of severe hypertriglyceridemia and in CVD prevention.

Omega-3-fatty acids: Do they prevent cardiovascular disease?

Despite cardiovascular disease (CVD) reductions with high-intensity statins, there remains residual risk among patients with metabolic disorders. Alongside low-density lipoproteins (LDL-C), elevated triglycerides (TG) are associated with incident CVD events. Omega-3 fatty acids (n3-FAs), specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), lower TG levels, but their ability to reduce CV risk has been highly inconsistent. Trials using icosapent ethyl (IPE), a purified EPA ethyl ester, produced reductions in CVD events and atherosclerotic plaque regression compared with mixed EPA/DHA formulations despite similar TG-reductions. The separate effects of EPA and DHA on tissue distribution, oxidative stress, inflammation, membrane structure and endothelial function may contribute to these discordant outcomes. Additional mechanistic trials will provide further insights into the role of n3-FAs in reducing CVD risk beyond TG lowering.

The role of apolipoprotein C3 in the regulation of nonalcoholic fatty liver disease, glucose and lipid metabolism, and islet β cell function / 生理学报

As a member of the apolipoprotein C (ApoC) family with a relatively high content, ApoC3 plays a major role in the regulation of triglyceride metabolism, and plays an important role in the occurrence and development of cardiovascular diseases, glucose and lipid metabolism disorders. Nonalcoholic fatty liver disease (NAFLD) refers to the accumulation of a large amount of fat in the liver in the absence of a history of chronic alcohol consumption or other damage to the liver. A large number of previous studies have shown that there is a correlation between the gene polymorphism and high expression of ApoC3 and NAFLD. In the context of hypertriglyceridemia (HTG), this article reviews the relationship between ApoC3 and NAFLD, glucose and lipid metabolism, and islet β cell function, showing that ApoC3 can not only inhibit lipoprotein lipase (LPL) and hepatic lipase (HL) activity, delay the decomposition of triglyceride in plasma to maintain the body's energy metabolism during fasting, but also be significantly increased under insulin resistance, prompting the liver to secrete a large amount of very low-density lipoprotein (VLDL) to induce HTG. Therefore, targeting and inhibiting ApoC3 might become a new approach to treat HTG. Increasing evidence suggests that ApoC3 does not appear to be an independent "contributor" to NAFLD. Similarly, our previous studies have shown that ApoC3 is not an independent factor triggering islet β cell dysfunction in ApoC3 transgenic mice, but in a state of excess nutrition, HTG triggered by ApoC3 high expression may exacerbate the effects of hyperglycemia and insulin resistance on islet β cell function, and the underlying mechanism remains to be further discussed.

Recent Apolipoprotein CIII trials.

PURPOSE OF REVIEW: This review will briefly revise the evidence concerning the pharmacological inhibition of Apolipoprotein CIII (ApoCIII) in patients with hypertriglyceridemia. RECENT FINDINGS: ApoCIII is a plasma apolipoprotein playing a major role in the metabolism of triglyceride-rich lipoproteins, namely chylomicrons and very-low-density lipoproteins as well as in the pathological processes involved in atherosclerosis. Therefore, ApoCIII is a potential new target for reducing plasma levels of TRLs and, thereby, cardiovascular risk. In recent years, there have been extensive preclinical and clinical pharmacological studies aimed at testing drugs directed against ApoCIII. SUMMARY: In this review, firstly we will summarize the molecular function of ApoCIII in lipoprotein metabolism. Then, we will examine the lipid-lowering potential of the pharmacological inhibition of ApoCIII based on the results of clinical trial employing Volansesorsen, the first approved antisense therapeutic oligonucleotide against ApoCIII mRNA. The future perspectives for ApoCIII inhibition will be also revised.

Lipoprotein Lipase: Is It a Magic Target for the Treatment of Hypertriglyceridemia.

High levels of triglycerides (TG) and triglyceride-rich lipoproteins (TGRLs) confer a residual risk of cardiovascular disease after optimal low-density lipoprotein cholesterol (LDL-C)-lowering therapy. Consensus has been made that LDL-C is a non-arguable primary target for lipid lowering treatment, but the optimization of TGRL for reducing the remnant risk of cardiovascular diseases is urged. Omega-3 fatty acids and fibrates are used to reduce TG levels, but many patients still have high TG and TGRL levels combined with low high-density lipoprotein concentration that need to be ideally treated. Lipoprotein lipase (LPL) is a key regulator for TGs that hydrolyzes TGs to glycerol and free fatty acids in lipoprotein particles for lipid storage and consumption in peripheral organs. A deeper understanding of human genetics has enabled the identification of proteins regulating the LPL activity, which include the apolipoproteins and angiopoietin-like families. Novel therapeutic approach such as antisense oligonucleotides and monoclonal antibodies that regulate TGs have been developed in recent decades. In this article, we focus on the biology of LPL and its modulators and review recent clinical application, including genetic studies and clinical trials of novel therapeutics. Optimization of LPL activity to lower TG levels could eventually reduce incident atherosclerotic cardiovascular disease in conjunction with successful LDL-C reduction.

Evaluation of circulating extracellular vesicles and miRNA in neutered and obese female dogs.

Adipose tissue is a metabolic and endocrine organ, and its adipocytes can synthesize and secrete extracellular vesicles (EVs), thus allowing intercellular communication. EVs are nanoparticles that transport lipids, proteins, metabolites, and nucleic acids (mRNA and microRNAs). MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression. miR-132, miR-26b, and miR-155 are associated with obesity, lipid metabolism and adipogenesis. The aim of this study was to evaluate the enriched EVs fraction containing miRNAs (miR-132, miR-26b, and miR-155) in serum from obese female dogs. Thirty-two neutered females in good general condition were recruited, including 21 obese and 11 healthy controls. The initial evaluation of the females included a general physical examination and laboratory tests. Small EVs (sEVs) were isolated from whole blood by serial centrifugation and ultracentrifugation, and nanoparticle analysis was used to determine the size and concentration of serum sEVs. miRNAs were extracted from sEVs enriched fraction and analyzed by real-time polymerase chain reaction. Obese female dogs with hypertriglyceridemia showed an increase in the sEVs concentration and in the expression of miR-132 and miR-26b in sEVs enriched fraction. No changes were observed in the group of obese female dogs with normal serum biochemical profile and in relation to miR-155 expression. These results suggest that obese female dogs with hypertriglyceridemia may present alterations in sEVs and in the expression of miRNAs related to lipid metabolism and adipogenesis.

A protein of capillary endothelial cells, GPIHBP1, is crucial for plasma triglyceride metabolism.

GPIHBP1, a protein of capillary endothelial cells (ECs), is a crucial partner for lipoprotein lipase (LPL) in the lipolytic processing of triglyceride-rich lipoproteins. GPIHBP1, which contains a three-fingered cysteine-rich LU (Ly6/uPAR) domain and an intrinsically disordered acidic domain (AD), captures LPL from within the interstitial spaces (where it is secreted by parenchymal cells) and shuttles it across ECs to the capillary lumen. Without GPIHBP1, LPL remains stranded within the interstitial spaces, causing severe hypertriglyceridemia (chylomicronemia). Biophysical studies revealed that GPIHBP1 stabilizes LPL structure and preserves LPL activity. That discovery was the key to crystallizing the GPIHBP1-LPL complex. The crystal structure revealed that GPIHBP1's LU domain binds, largely by hydrophobic contacts, to LPL's C-terminal lipid-binding domain and that the AD is positioned to project across and interact, by electrostatic forces, with a large basic patch spanning LPL's lipid-binding and catalytic domains. We uncovered three functions for GPIHBP1's AD. First, it accelerates the kinetics of LPL binding. Second, it preserves LPL activity by inhibiting unfolding of LPL's catalytic domain. Third, by sheathing LPL's basic patch, the AD makes it possible for LPL to move across ECs to the capillary lumen. Without the AD, GPIHBP1-bound LPL is trapped by persistent interactions between LPL and negatively charged heparan sulfate proteoglycans (HSPGs) on the abluminal surface of ECs. The AD interrupts the HSPG interactions, freeing LPL-GPIHBP1 complexes to move across ECs to the capillary lumen. GPIHBP1 is medically important; GPIHBP1 mutations cause lifelong chylomicronemia, and GPIHBP1 autoantibodies cause some acquired cases of chylomicronemia.

Hypertriglyceridemia in Preterm Infants.

Preterm and critically ill infants are at risk for hypertriglyceridemia (HTG). Common risk factors for HTG include prematurity, intravenous lipid emulsion dose and oil composition, reduced lipoprotein lipase activity, fetal growth restriction, sepsis, and renal failure. Despite these risk factors, clinicians lack a universally agreed upon definition for HTG and evidence-based approach to HTG management. This review provides a detailed overview of triglyceride and intravenous lipid emulsion metabolism and how this relates to specific HTG risk factors, along with some practical considerations for managing HTG in the neonatal population.