Lipid signaling and lipotoxicity in metaflammation: indications for metabolic disease pathogenesis and treatment

Silencing the FABP3 gene in insulin-secreting cells reduces fatty acid uptake and protects against lipotoxicity

BACKGROUND

Long-term exposure of pancreatic islets to fatty acids (FAs), common in obesity, metabolic syndrome, and type 2 diabetes, leads to a compensatory hyperactivity followed by inflammation, apoptosis, dysfunctional beta cells, and results in insulin dependence of the patient. Restriction of fatty uptake by islet beta cells may protect them from lipotoxicity.

PURPOSE

Pancreatic islet beta cells express the fatty acid binding protein 3 (FABP3) to bind FAs and to orchestrate lipid signals. Based on this, we investigated whether downregulation of FABP3, by Fabp3 silencing, might slow lipid metabolism and protect against lipotoxicity in insulin-secreting cells.

RESULTS

Neither Fabp3 silencing, nor overexpression affected the glucose-stimulated insulin secretion in absence of FAs. Fabp3 silencing decreased FA-uptake, lipid droplets formation, and the expression of the lipid accumulation-regulating gene Dgat1 in Ins1E cells. It reduced FA-induced inflammation by deactivation of NF-κB, which was associated with upregulation of IκBα and deactivation of the NF-κB p65 nuclear translocation, and the downregulation of the cytokines ILl-6, IL-1β, and TNFα. Ins1E cells were protected from the FA-induced apoptosis as assessed by different parameters including DNA degradation and cleaved caspase-3 immunoblotting. Furthermore, FABP3 silencing improved the viability, Pdx1 gene expression, and the insulin-secreting function in cells long-term cultured with palmitic acid. All results were confirmed by the opposite action rendered by FABP3 overexpression.

CONCLUSION

The present data reveals that pancreatic beta cells can be protected from lipotoxicity by inhibition of FA-uptake, intracellular utilization and accumulation. FABP3 inhibition, hence, may be a useful pharmaceutical approach in obesity, metabolic syndrome, and type 2 diabetes.

Obesity, dyslipidemia, and cardiovascular disease: A joint expert review from the Obesity Medicine Association and the National Lipid Association 2024

Background

This joint expert review by the Obesity Medicine Association (OMA) and National Lipid Association (NLA) provides clinicians an overview of the pathophysiologic and clinical considerations regarding obesity, dyslipidemia, and cardiovascular disease (CVD) risk.

Methods

This joint expert review is based upon scientific evidence, clinical perspectives of the authors, and peer review by the OMA and NLA leadership.

Results

Among individuals with obesity, adipose tissue may store over 50% of the total body free cholesterol. Triglycerides may represent up to 99% of lipid species in adipose tissue. The potential for adipose tissue expansion accounts for the greatest weight variance among most individuals, with percent body fat ranging from less than 5% to over 60%. While population studies suggest a modest increase in blood low-density lipoprotein cholesterol (LDL-C) levels with excess adiposity, the adiposopathic dyslipidemia pattern most often described with an increase in adiposity includes elevated triglycerides, reduced high density lipoprotein cholesterol (HDL-C), increased non-HDL-C, elevated apolipoprotein B, increased LDL particle concentration, and increased small, dense LDL particles.

Conclusions

Obesity increases CVD risk, at least partially due to promotion of an adiposopathic, atherogenic lipid profile. Obesity also worsens other cardiometabolic risk factors. Among patients with obesity, interventions that reduce body weight and improve CVD outcomes are generally associated with improved lipid levels. Given the modest improvement in blood LDL-C with weight reduction in patients with overweight or obesity, early interventions to treat both excess adiposity and elevated atherogenic cholesterol (LDL-C and/or non-HDL-C) levels represent priorities in reducing the risk of CVD.

MASLD/MASH and type 2 diabetes: Two sides of the same coin? From single PPAR to pan-PPAR agonists

Type 2 diabetes (T2D) and metabolic dysfunction-associated steatotic liver disease (MASLD), mainly related to nutrition and lack of physical activity, are both very common conditions, share several disease pathways and clinical manifestations, and increasingly co-occur with disease progression. Insulin resistance is an upstream node in the biology of both conditions and triggers liver parenchymal injury, inflammation and fibrosis. Peroxisome proliferator-activated receptor (PPAR) nuclear transcription factors are master regulators of energy homeostasis - insulin signaling in liver, adipose and skeletal muscle tissue - and affect immune and fibrogenesis pathways. Among distinct yet overlapping effects, PPARα regulates lipid metabolism and energy expenditure, PPARβ/δ has anti-inflammatory effects and increases glucose uptake by skeletal muscle, while PPARγ improves insulin sensitivity and exerts direct antifibrotic effects on hepatic stellate cells. Together PPARs thus represent pharmacological targets across the entire biology of MASH. Single PPAR agonists are approved for hypertriglyceridemia (PPARα) and T2D (PPARγ), but these, as well as dual PPAR agonists, have shown mixed results as anti-MASH treatments in clinical trials. Agonists of all three PPAR isoforms have the potential to improve the full disease spectrum from insulin resistance to fibrosis, and correspondingly to improve cardiometabolic and hepatic health, as has been shown (phase II data) with the pan-PPAR agonist lanifibranor.

Plant- and Animal-Derived Dietary Sources of Phosphatidylcholine Have Differential Effects on Immune Function in The Context of A High-Fat Diet in Male Wistar Rats

BACKGROUND

Phosphatidylcholine (PC) derived from eggs has been shown to beneficially modulate T cell response and intestinal permeability under the context of a high-fat diet.

OBJECTIVES

The objective of this study was to determine whether there is a differential effect of plant and animal-derived sources of PC on immune function.

METHODS

Four-week-old male Wistar rats were randomly assigned to consume 1 of 4 diets (n = 10/group) for 12 wk, all containing 1.5 g of total choline/kg of diet but differing in choline forms: 1-Control Low-Fat [CLF, 20% fat, 100% free choline (FC)]; 2-Control High-Fat (CHF, 50% fat, 100% FC); 3-High-Fat Egg-derived PC (EPC, 50% fat, 100% Egg-PC); 4-High-Fat Soy-derived PC (SPC, 50% fat, 100% Soy-PC). Immune cell functions and phenotypes were measured in splenocytes by ex vivo cytokine production after mitogen stimulation and flow cytometry, respectively.

RESULTS

The SPC diet increased splenocyte IL-2 production after PMA+I stimulation compared with the CHF diet. However, the SPC group had a lower proportion of splenocytes expressing the IL-2 receptor (CD25+, P < 0.05). After PMA+I stimulation, feeding EPC normalized splenocyte production of IL-10 relative to the CLF diet, whereas SPC did not (P < 0.05). In mesenteric lymph node lymphocytes, the SPC diet group produced more IL-2 and TNF-α after PMA+I stimulation than the CHF diet, whereas the EPC diet group did not.

CONCLUSIONS

Our results suggest that both egg- and soy-derived PC may attenuate high-fat diet-induced T cell dysfunction. However, egg-PC enhances, to a greater extent, IL-10, a cytokine involved in promoting the resolution phase of inflammation, whereas soy-PC appears to elicit a greater effect on gut-associated immune responses.

Obesity, dyslipidemia, and cardiovascular disease: A joint expert review from the Obesity Medicine Association and the National Lipid Association 2024

BACKGROUND

This joint expert review by the Obesity Medicine Association (OMA) and National Lipid Association (NLA) provides clinicians an overview of the pathophysiologic and clinical considerations regarding obesity, dyslipidemia, and cardiovascular disease (CVD) risk.

METHODS

This joint expert review is based upon scientific evidence, clinical perspectives of the authors, and peer review by the OMA and NLA leadership.

RESULTS

Among individuals with obesity, adipose tissue may store over 50% of the total body free cholesterol. Triglycerides may represent up to 99% of lipid species in adipose tissue. The potential for adipose tissue expansion accounts for the greatest weight variance among most individuals, with percent body fat ranging from less than 5% to over 60%. While population studies suggest a modest increase in blood low-density lipoprotein cholesterol (LDL-C) levels with excess adiposity, the adiposopathic dyslipidemia pattern most often described with an increase in adiposity includes elevated triglycerides, reduced high-density lipoprotein cholesterol (HDL-C), increased non-HDL-C, elevated apolipoprotein B, increased LDL particle concentration, and increased small, dense LDL particles.

CONCLUSIONS

Obesity increases CVD risk, at least partially due to promotion of an adiposopathic, atherogenic lipid profile. Obesity also worsens other cardiometabolic risk factors. Among patients with obesity, interventions that reduce body weight and improve CVD outcomes are generally associated with improved lipid levels. Given the modest improvement in blood LDL-C with weight reduction in patients with overweight or obesity, early interventions to treat both excess adiposity and elevated atherogenic cholesterol (LDL-C and/or non-HDL-C) levels represent priorities in reducing the risk of CVD.

Tigilanol tiglate is an oncolytic small molecule that induces immunogenic cell death and enhances the response of both target and non-injected tumors to immune checkpoint blockade

BACKGROUND

Tigilanol tiglate (TT) is a protein kinase C (PKC)/C1 domain activator currently being developed as an intralesional agent for the treatment of various (sub)cutaneous malignancies. Previous work has shown that intratumoral (I.T.) injection of TT causes vascular disruption with concomitant tumor ablation in several preclinical models of cancer, in addition to various (sub)cutaneous tumors presenting in the veterinary clinic. TT has completed Phase I dose escalation trials, with some patients showing signs of abscopal effects. However, the exact molecular details underpinning its mechanism of action (MoA), together with its immunotherapeutic potential in oncology remain unclear.

METHODS

A combination of microscopy, luciferase assays, immunofluorescence, immunoblotting, subcellular fractionation, intracellular ATP assays, phagocytosis assays and mixed lymphocyte reactions were used to probe the MoA of TT in vitro. In vivo studies with TT used MM649 xenograft, CT-26 and immune checkpoint inhibitor refractory B16-F10-OVA tumor bearing mice, the latter with or without anti-programmed cell death 1 (PD-1)/anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) mAb treatment. The effect of TT at injected and non-injected tumors was also assessed.

RESULTS

Here, we show that TT induces the death of endothelial and cancer cells at therapeutically relevant concentrations via a caspase/gasdermin E-dependent pyroptopic pathway. At therapeutic doses, our data demonstrate that TT acts as a lipotoxin, binding to and promoting mitochondrial/endoplasmic reticulum (ER) dysfunction (leading to unfolded protein responsemt/ER upregulation) with subsequent ATP depletion, organelle swelling, caspase activation, gasdermin E cleavage and induction of terminal necrosis. Consistent with binding to ER membranes, we found that TT treatment promoted activation of the integrated stress response together with the release/externalization of damage-associated molecular patterns (HMGB1, ATP, calreticulin) from cancer cells in vitro and in vivo, characteristics indicative of immunogenic cell death (ICD). Confirmation of ICD in vivo was obtained through vaccination and rechallenge experiments using CT-26 colon carcinoma tumor bearing mice. Furthermore, TT also reduced tumor volume, induced immune cell infiltration, as well as improved survival in B16-F10-OVA tumor bearing mice when combined with immune checkpoint blockade.

CONCLUSIONS

These data demonstrate that TT is an oncolytic small molecule with multiple targets and confirms that cell death induced by this compound has the potential to augment antitumor responses to immunotherapy.

Overnutrition and Lipotoxicity: Impaired Efferocytosis and Chronic Inflammation as Precursors to Multifaceted Disease Pathogenesis

Overnutrition, driven by the consumption of high-fat, high-sugar diets, has reached epidemic proportions and poses a significant global health challenge. Prolonged overnutrition leads to the deposition of excessive lipids in adipose and non-adipose tissues, a condition known as lipotoxicity. The intricate interplay between overnutrition-induced lipotoxicity and the immune system plays a pivotal role in the pathogenesis of various diseases. This review aims to elucidate the consequences of impaired efferocytosis, caused by lipotoxicity-poisoned macrophages, leading to chronic inflammation and the subsequent development of severe infectious diseases, autoimmunity, and cancer, as well as chronic pulmonary and cardiovascular diseases. Chronic overnutrition promotes adipose tissue expansion which induces cellular stress and inflammatory responses, contributing to insulin resistance, dyslipidemia, and metabolic syndrome. Moreover, sustained exposure to lipotoxicity impairs the efferocytic capacity of macrophages, compromising their ability to efficiently engulf and remove dead cells. The unresolved chronic inflammation perpetuates a pro-inflammatory microenvironment, exacerbating tissue damage and promoting the development of various diseases. The interaction between overnutrition, lipotoxicity, and impaired efferocytosis highlights a critical pathway through which chronic inflammation emerges, facilitating the development of severe infectious diseases, autoimmunity, cancer, and chronic pulmonary and cardiovascular diseases. Understanding these intricate connections sheds light on potential therapeutic avenues to mitigate the detrimental effects of overnutrition and lipotoxicity on immune function and tissue homeostasis, thereby paving the way for novel interventions aimed at reducing the burden of these multifaceted diseases on global health.

D-Allulose Reduces Hypertrophy and Endoplasmic Reticulum Stress Induced by Palmitic Acid in Murine 3T3-L1 Adipocytes

Natural rare sugars are an alternative category of sweeteners with positive physiologic and metabolic effects both in in vitro and animal models. D-allulose is a D-fructose epimer that combines 70% sucrose sweetness with the advantage of an extremely low energy content. However, there are no data about the effect of D-allulose against adipose dysfunction; thus, it remains to be confirmed whether D-allulose is useful in the prevention and in treatment of adipose tissue alterations. With this aim, we evaluated D-allulose's preventive effects on lipid accumulation in 3T3-L1 murine adipocytes exposed to palmitic acid (PA), a trigger for hypertrophic adipocytes. D-allulose in place of glucose prevented adipocyte hypertrophy and the activation of adipogenic markers C/EBP-β and PPARγ induced by high PA concentrations. Additionally, D-allulose pretreatment inhibited the NF-κB pathway and endoplasmic reticulum stress caused by PA, through activation of the Nrf2 pathway. Interestingly, these effects were also observed as D-allulose post PA treatment. Although our data need to be confirmed through in vivo models, our findings suggest that incorporating D-allulose as a glucose substitute in the diet might have a protective role in adipocyte function and support a unique mechanism of action in this sugar as a preventive or therapeutic compound against PA lipotoxicity through the modulation of pathways connected to lipid transport and metabolism.

Triglyceride Glucose Index as an Indicator of Cardiovascular Risk in Syrian Refugees

Background

The triglyceride glucose (TyG) index is a quick and inexpensive approach to measure insulin resistance. The aim of this study was to evaluate the TyG index's ability to predict cardiovascular risk and determine the TyG index cutoff values in Syrian refugees.

Methods

A retrospective research study was conducted with 756 Syrian refugees. Data on demographics and clinical laboratory assessments were obtained from refugee's files. The formula Ln [fasting triglycerides (mg/dL) × fasting plasma glucose (mg (dL)/2] was used to calculate the TyG index. The Framingham risk score was used to calculate ten-year cardiovascular risk. The TyG index cutoff point was determined using the receiver operating characteristic curve (ROC).

Results

Included participants had a mean age of 56.76 ± 10.78 years and a mean body mass index (BMI) of 27.42 ± 4.03 kg/m2. 28.57% of the subjects were smokers, and the majority were female (56.75%). A significant moderate correlation was observed between TyG index and Framingham score (r = 0.428, p < 0.001). ROC curve analysis for TyG index and Framingham score showed an area under the curve (AUC) of 0.741 (95% CI = 0.691-0.791; p < 0.001). The cutoff value of the TyG index to recognize intermediate/high risk Framingham risk score was 9.33, with a sensitivity of 64.3%, and specificity of 75.0%.

Conclusion

Our findings determine that, given a TyG index cutoff value of 9.33, the TyG index has a predictive ability to assess ten-year cardiovascular risk by comparison to the Framingham risk score in a high-risk group of Syrian refugees and can be used as an independent indicator of cardiovascular risk.

Expression of immune related genes and possible regulatory mechanisms in different stages of non-alcoholic fatty liver disease

Background

Non-alcoholic fatty liver disease (NAFLD), which includes simple steatosis (SS) and non-alcoholic steatohepatitis (NASH), is a significant contributor to liver disease on a global scale. The change of immunity-related genes (IRGs) expression level leads to different immune infiltrations. However, the expression of IRGs and possible regulatory mechanisms involved in NAFLD remain unclear. The objective of our research is to investigate crucial genes linked to the development of NAFLD and the transition from SS to NASH.

Methods

Dataset GSE89632, which includes healthy controls, SS patients, and NASH patients, was obtained using the GEO database. To examine the correlation between sets of genes and clinical characteristics, we employed weighted gene co-expression network analysis (WGCNA) and differential expression analysis. Hub genes were extracted using a network of protein-protein interactions (PPI) and three different machine learning algorithms. To validate the findings, another dataset that is publicly accessible and mice that were subjected to a high-fat diet (HFD) or MCD diet were utilized. Furthermore, the ESTIMATE algorithm and ssGSEA were employed to investigate the immune landscape in the normal versus SS group and SS versus NASH group, additionally, the relationship between immune infiltration and the expression of hub genes was also examined.

Results

A total of 28 immune related key genes were selected. Most of these genes expressed reverse patterns in the initial and progressive stages of NAFLD. GO and KEGG analyses showed that they were focused on the cytokine related pathways and immune cell activation and chemotaxis. After screening by various algorithms, we obtained two hub genes, including JUN and CCL20. Validation of these findings was confirmed by analyzing gene expression patterns in both the validation dataset and the mouse model. Ultimately, two hub genes were discovered to have a significant correlation with the infiltration of immune cells.

Conclusion

We proposed that there were dynamic changes in the expression levels of IRGs in different stages of NAFLD disease, which led to different immune landscapes in SS and NASH. The findings of our research could serve as a guide for the accurate management of various phases of NAFLD.

The metabolic load-capacity model and cardiometabolic health in children and youth with obesity

BACKGROUND

The metabolic load-capacity index (LCI), which represents the ratio of adipose to skeletal muscle tissue-containing compartments, is potentially associated with cardiometabolic diseases.

OBJECTIVES

To examine the associations between the LCI and cardiometabolic risk factors in children and youth with obesity.

METHODS

This is a cross-sectional study including 10-18 years-old participants with a BMI of ≥95th . LCI by air-displacement plethysmography (ADP) was calculated as fat mass divided by fat-free mass, and LCI by ultrasound (US) as subcutaneous adipose tissue divided by skeletal muscle thickness. Sex-specific medians stratified participants into high versus low LCI. Single (inflammation, insulin resistance, dyslipidemia and hypertension) and clustered cardiometabolic risk factors were evaluated. Linear and logistic regression models tested the associations between these variables, adjusted for sexual maturation.

RESULTS

Thirty-nine participants (43.6% males; 59% mid-late puberty) aged 12.5 (IQR: 11.1-13.5) years were included. LCI by ADP was positively associated with markers of inflammation and dyslipidemia; having a higher LCI predicted dyslipidemia in logistic regression. Similarly, LCI by US was positively associated with markers of dyslipidemia and blood pressure. In mid-late pubertal participants, LCI by US was positively associated with markers of insulin resistance and inflammation.

CONCLUSIONS

Participants with unfavourable cardiometabolic profile had higher LCI, suggesting its potential use for predicting and monitoring cardiometabolic health in clinical settings.

The chemical and biological characteristics of fatty acid esters of hydroxyl fatty acids

With the continuous advancements in detection methods and the exploration of unknown substances, an increasing number of bioactive compounds are being discovered. Fatty acid esters of hydroxyl fatty acids (FAHFAs), a class of endogenous lipids found in 2014, exhibit various physiological activities, such as improving glucose tolerance and insulin sensitivity, stimulating insulin secretion, and demonstrating broad anti-inflammatory effects. Moreover, some FAHFAs are closely linked to intestinal health and can serve as potential biomarkers for gut health. Various FAHFAs have been observed in food, including palmitic acid esters of hydroxy stearic acids (PAHSA), oleic acid esters of hydroxy stearic acids (OAHSA), linoleic acid esters of hydroxy linoleic acid (LAHLA). As a type of lipid regularly consumed in the daily diet, it is highly important to ascertain the types and quantities of FAHFAs present in the diet. This article, based on existing research, provides a review of the analysis methods for FAHFAs, particularly focusing on the separation of chiral isomers. It also summarizes the sources and contents of dietary FAHFAs, emphasizing their bioavailability and impact on the gut. Understanding the beneficial effects of these lipids in the diet can serve as a valuable reference for the development of specific functional foods.

Increased fatty acid synthesis and disturbed lipid metabolism in Neuro2a cells after repeated cocaine exposure: A preliminary study

Chronic use of cocaine prompts neurodegeneration and neuroinflammation. Lipids play pivotal roles in neuronal function and pathology. Although evidence correlates cocaine use with the alteration of lipid metabolism in blood and brain, the precise mechanism remains to be elucidated. In this study, we explore the effect of cocaine on neuronal fatty acid profiles in vitro. Neuro2a cells following seven days of repeated exposure to cocaine (0, 600, 800, 1000 μM) showed apoptosis-irrelevant cell death, dysregulated autophagy, activation of atypical endoplasmic reticulum stress response, increased saturated and unsaturated fatty acid synthesis, and disrupted lipid metabolism. These preliminary findings indicated the association between lipid metabolism and cocaine-induced neurotoxicity, which should be beneficial for understanding the neurotoxicity of cocaine.

Interesterified palm oil promotes insulin resistance and altered insulin secretion and signaling in Swiss mice

Interesterified fats have been used to replace trans-fat in ultra-processed foods. However, their metabolic effects are not completely understood. Hence, this study aimed to investigate the effects related to glucose homeostasis in response to interesterified palm oil or refined palm oil intake. Four-week-old male Swiss mice were randomly divided into four experimental groups and fed the following diets for 8 weeks: a normocaloric and normolipidic diet containing refined palm oil (PO group) or interesterified palm oil (IPO group); a hypercaloric and high-fat diet containing refined PO (POHF group) or interesterified PO (IPOHF group). Metabolic parameters related to body mass, adiposity and food consumption showed no significant differences. As for glucose homeostasis parameters, interesterified palm oil diets (IPO and IPOHF) resulted in higher glucose intolerance than unmodified palm oil diets (PO and POHF). Euglycemic-hyperinsulinemic clamp assessment showed a higher endogenous glucose production in the IPO group compared with the PO group. Moreover, the IPO group showed significantly lower p-AKT protein content (in the muscle and liver tissues) when compared with the PO group. Analysis of glucose-stimulated static insulin secretion (11.1 mmol/L glucose) in isolated pancreatic islets showed a higher insulin secretion in animals fed interesterified fat diets (IPO and IPOHF) than in those fed with palm oil (PO and POHF). Interesterified palm oil, including in normolipidic diets, can impair insulin signaling in peripheral tissues and increase insulin secretion by β-cells, characterizing insulin resistance in mice.

A Plasma Exosomal Metabolic Profiling of Nonalcoholic Fatty Liver Disease Patients Complicated with Impaired Fasting Glucose

BACKGROUND/AIMS

Nonalcoholic fatty liver disease is considered as the hepatic manifestation of metabolic syndrome. Detection of circulating exosomes together with metabolomic analysis of their cargo would provide early signals for metabolic derangements and complications associated with nonalcoholic fatty liver disease. Therefore, this study profiled exosomal metabolome of patients with nonalcoholic fatty liver disease and impaired fasting glucose.

MATERIALS AND METHODS

Plasma exosomes were extracted from nonalcoholic fatty liver disease patients with or without impaired fasting glucose through differential ultracentrifugation. Their metabolite profiles were examined by ultrahigh-performance liquid chrom atography-quadrupole time-of-flight mass spectrometry. Pathway analysis was carried out on platform MetaboAnalyst 4.0.

RESULTS

Thirty-nine patients were enrolled, including nonalcoholic fatty liver disease-alone group (n = 26) and age-and gender-comparable nonalcoholic fatty liver disease plus impaired fasting glucose group (n = 13). Although less than and different from their plasma counterparts, a total of 10 significantly differential exosomal metabolites were identified. Nonalcoholic fatty liver disease plus impaired fasting glucose group had higher concentrations of linoleic acid, palmitamide, stearamide, and oleamide, as well as a lower concentration of phosphatidylethanolamine [20:5(5Z,8Z,11Z,14Z,17Z)/20:5(5Z,8Z,11Z,14Z,17Z)]. Pathway analysis showed an obviously changed metabolism of linoleic acid.

CONCLUSION

Metabolomic analysis of plasma exosomes revealed a distinct change in fatty acids and related pathways in nonalcoholic fatty liver disease patients with impaired fasting glucose. These preliminary results provide a metabolomic snapshot and basis for further investigation of exosome biology for these patients.

New Therapeutic Approaches for the Treatment of Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) and Increased Cardiovascular Risk

Metabolic dysfunction-associated steatotic liver disease (MASLD) was previously known as nonalcoholic fatty liver disease (NAFLD). The main characteristic of the disease is the process of long-term liver inflammation, which leads to hepatocyte damage followed by liver fibrosis and eventually cirrhosis. Additionally, these patients are at a greater risk for developing cardiovascular diseases (CVD). They have several pathophysiological mechanisms in common, primarily lipid metabolism disorders and lipotoxicity. Lipotoxicity is a factor that leads to the occurrence of heart disease and the occurrence and progression of atherosclerosis. Atherosclerosis, as a multifactorial disease, is one of the predominant risk factors for the development of ischemic heart disease. Therefore, CVD are one of the most significant carriers of mortality in patients with metabolic syndrome. So far, no pharmacotherapy has been established for the treatment of MASLD, but patients are advised to reduce their body weight and change their lifestyle. In recent years, several trials of different drugs, whose basic therapeutic indications include other diseases, have been conducted. Because it has been concluded that they can have beneficial effects in the treatment of these conditions as well, in this paper, the most significant results of these studies will be presented.

Association Between Nutrients and Cardiovascular Diseases

Cardiovascular diseases (CVD) constitute a leading cause of global mortality. Inflammation and oxidative stress are key molecular underpinnings of CVD pathogenesis. This comprehensive review explores the multifaceted role of nutrients in cardiovascular health beyond their impact on cardiac events. The manuscript examines the influence of macronutrients such as fats and carbohydrates, as well as micronutrients including vitamins and folate, on CVD. Additionally, the interplay between dietary supplements and CVD risk reduction is investigated. The purpose of this manuscript is to provide a comprehensive overview of the diverse mechanisms through which nutrients contribute to cardiovascular well-being, addressing both cardioprotective effects and their broader implications. Through an analysis of pertinent studies, we illuminate the complex relationship between nutrition, lifestyle, and cardiovascular health, underscoring the significance of a holistic approach to CVD prevention and management.

6-Gingerol regulates triglyceride and cholesterol biosynthesis to improve hepatic steatosis in MAFLD by activating the AMPK-SREBPs signaling pathway

Excessive synthesis of triglycerides and cholesterol accelerates the progression of hepatic steatosis in metabolic-associated fatty liver disease (MAFLD). However, the precise mechanism by which 6-gingerol mitigates hepatic steatosis in MAFLD model mice has yet to be fully understood. The present study observed that 6-gingerol administration exhibited significant protective effects against obesity, insulin resistance, and hepatic steatosis in mice subjected to a high-fat diet (HFD), and mitigated lipid accumulation in HepG2 cells treated with palmitate (PA). Following the hepatic lipidomic analysis, we confirmed that the AMPK-SREBPs signaling pathway as the underlying molecular mechanism by which 6-gingerol inhibited triglyceride and cholesterol biosynthesis, both in vivo and in vitro, through Western blot and immunofluorescence assay. Additionally, the application of an AMPK agonist/inhibitor further validated that 6-gingerol promoted AMPK activation by increasing the phosphorylation level of AMPK in vitro. Notably, the inhibitory effect of 6-gingerol on cholesterol biosynthesis, rather than triglyceride biosynthesis, was significantly diminished after silencing SREBP2 using a lentiviral plasmid shRNA in HepG2 cells. Our study demonstrates that 6-gingerol mitigates hepatic triglyceride and cholesterol biosynthesis to alleviate hepatic steatosis by activating the AMPK-SREBPs signaling pathway, indicating that 6-gingerol may be a potential candidate in the therapy of MAFLD.

Mitochondrial electron transport chain, ceramide, and coenzyme Q are linked in a pathway that drives insulin resistance in skeletal muscle

Insulin resistance (IR) is a complex metabolic disorder that underlies several human diseases, including type 2 diabetes and cardiovascular disease. Despite extensive research, the precise mechanisms underlying IR development remain poorly understood. Previously we showed that deficiency of coenzyme Q (CoQ) is necessary and sufficient for IR in adipocytes and skeletal muscle (Fazakerley et al., 2018). Here, we provide new insights into the mechanistic connections between cellular alterations associated with IR, including increased ceramides, CoQ deficiency, mitochondrial dysfunction, and oxidative stress. We demonstrate that elevated levels of ceramide in the mitochondria of skeletal muscle cells result in CoQ depletion and loss of mitochondrial respiratory chain components, leading to mitochondrial dysfunction and IR. Further, decreasing mitochondrial ceramide levels in vitro and in animal models (mice, C57BL/6J) (under chow and high-fat diet) increased CoQ levels and was protective against IR. CoQ supplementation also rescued ceramide-associated IR. Examination of the mitochondrial proteome from human muscle biopsies revealed a strong correlation between the respirasome system and mitochondrial ceramide as key determinants of insulin sensitivity. Our findings highlight the mitochondrial ceramide-CoQ-respiratory chain nexus as a potential foundation of an IR pathway that may also play a critical role in other conditions associated with ceramide accumulation and mitochondrial dysfunction, such as heart failure, cancer, and aging. These insights may have important clinical implications for the development of novel therapeutic strategies for the treatment of IR and related metabolic disorders.

PP2Ac knockdown attenuates lipotoxicity‑induced pancreatic β‑cell dysfunction and apoptosis

Protein phosphatase 2A (PP2A) is one of the most common serine/threonine phosphatases in mammalian cells, and it primarily functions to regulate cell signaling, glycolipid metabolism and apoptosis. The catalytic subunit of PP2A (PP2Ac) plays an important role in the functions of the protein. However, there are few reports on the regulatory role of PP2Ac in pancreatic β-cells under lipotoxic conditions. In the present study, mouse insulinoma 6 (MIN6) pancreatic cells were transfected with short hairpin RNAs to generate PP2Ac knockdown cells and incubated with palmitate (PA) to establish a lipotoxicity model. Serine/threonine phosphatase assay system, Cell Counting Kit-8, flow cytometry, enzyme-linked immunosorbent assay and western blotting were used to measure PP2A activity, cell viability, apoptosis, oxidative stress and insulin secretion in the cells. In addition, a mouse model of lipotoxicity was established with a high-fat diet (HFD) and the knockdown of PP2Ac using adeno-associated viruses to interfere with PP2Ac expression in the pancreatic tissues. The activity of PP2A in the mouse pancreatic tissue and the serum insulin level were measured. Furthermore, the proliferation of mouse pancreatic β-cells was assessed using pancreatic tissue immunofluorescence. PP2Ac knockdown inhibited lipotoxicity-induced PP2A hyperactivation, increased the resistance of pancreatic β-cells to lipotoxicity and attenuated PA-induced apoptosis in MIN6 cells. It also protected the endoplasmic reticulum and mitochondria, and ameliorated insulin secretion. The results of mRNA sequencing and western blotting analysis suggested that the protective effects of PP2Ac knockdown in MIN6 cells may be mediated via the MAPK pathway. Moreover, the results of the animal experiments suggested that specific knockdown of pancreatic PP2Ac effectively attenuated HFD-induced insulin resistance and reduced the compensatory proliferation of pancreatic β-cells in mice. In summary, the present study revealed the effects of interfering with PP2Ac gene expression on pancreatic β-cells in vivo and in vitro and the underlying mechanisms, which may provide insights for the treatment of type 2 diabetes mellitus in the clinic.

ABHD6 suppression promotes anti-inflammatory polarization of adipose tissue macrophages via 2-monoacylglycerol/PPAR signaling in obese mice

OBJECTIVE

Pro-inflammatory polarization of adipose tissue macrophages (ATMs) plays a critical role in the pathogenesis of obesity-associated chronic inflammation. However, little is known about the role of lipids in the regulation of ATMs polarity and inflammation in response to metabolic stress. Deletion of α/β-hydrolase domain-containing 6 (ABHD6), a monoacylglycerol (MAG) hydrolase, has been shown to protect against diet-induced obesity and insulin resistance.

METHODS

Here we investigated the immunometabolic role of macrophage ABHD6 in response to nutrient excess using whole-body ABHD6-KO mice and human and murine macrophage cell-lines treated with KT203, a selective and potent pharmacological ABHD6 inhibitor.

RESULTS

KO mice on high-fat diet showed lower susceptibility to systemic diet-induced inflammation. Moreover, in the setting of overnutrition, stromal vascular cells from gonadal fat of KO vs. control mice contained lower number of M1 macrophages and exhibited enhanced levels of metabolically activated macrophages (MMe) and M2 markers, oxygen consumption, and interleukin-6 (IL-6) release. Likewise, under in vitro nutri-stress condition, inhibition of ABHD6 in MMe-polarized macrophages attenuated the expression and release of pro-inflammatory cytokines and M1 markers and induced the upregulation of lipid metabolism genes. ABHD6-inhibited MMe macrophages showed elevated levels of peroxisome proliferator-activated receptors (PPARs) and 2-MAG species. Notably, among different MAG species, only 2-MAG treatment led to increased levels of PPAR target genes in MMe macrophages.

CONCLUSIONS

Collectively, our findings identify ABHD6 as a key component of pro-inflammatory macrophage activation in response to excess nutrition and implicate an endogenous macrophage lipolysis/ABHD6/2-MAG/PPARs cascade, as a lipid signaling and immunometabolic pathway, which favors the anti-inflammatory polarization of ATMs in obesity.

Echo time optimization for in-vivo measurement of unsaturated lipid resonances using J-difference-edited MRS

PURPOSE

Measuring lipid composition provides more information than just total lipid content. Hence, the non-invasive measurement of unsaturated lipid protons with both high efficiency and precision is of pressing need. This study was to optimize echo time (TE) for the best resolving of J-difference editing of unsaturated lipid resonances.

METHODS

The TE dependence of J-difference-edited (JDE) MRS was verified in the density-matrix simulation, soybean oil phantom, in-vivo experiments of white adipose tissue (WAT), and skeletal muscles using single-voxel MEGA-PRESS sequence at 3T. The peak SNRs and Cramér-Rao lower bounds (CRLBs) acquired at the proposed TE of 45 ms and previously published TE of 70 ms were compared (eight pairs) in WAT, extramyocelluar lipids (EMCLs), and intramyocellular lipids (IMCLs). The lipid composition in skeletal muscles was compared between healthy males (n = 7) and females (n = 7).

RESULTS

The optimal TE was suggested as 45 ms. Compared to 70 ms, the mean signal gains at TE of 45 ms were 151% in WAT, 168% in EMCL, 204% in IMCL for allylic resonance, and 52% in EMCL for diallylic resonance. CRLBs were significantly reduced at TE of 45 ms in WAT, EMCL, IMCL for allylic resonance and in EMCL for diallylic resonance. With TE of 45 ms, significant gender differences were found in the lipid composition in EMCL pools, while no difference in IMCL pools.

CONCLUSION

The JDE-MRS protocol with TE of 45 ms allows improved quantification of unsaturated lipid resonances in vivo and future lipid metabolism investigations.

Garcinia cambogia Extract Increased Hepatic Levels of Lipolysis-Stimulated Lipoprotein Receptor and Lipids in Mice on Normal Diet

Garcinia cambogia extract (GCE) is a popular weight-loss supplement that also lowers plasma triglyceride (TG) levels. We hypothesized that GCE-mediated inhibition of ATP citrate lyase and thereby hepatic TG production could lead to compensatory mechanisms, including increased hepatic TG uptake via lipoprotein receptors. GCE (20 mg/day) administered 40 days orally to female C57BL/6Rj mice on a standard chow diet led to a decrease in both plasma fasting and post-prandial TG-rich lipoprotein levels, but with no significant change in body weight gain. Lipolysis stimulated lipoprotein receptor (LSR) protein levels, but not those of LDL-receptor, were increased as compared to controls. Mouse Hepa1-6 cells treated with the GCE active ingredient, hydroxycitrate, also led to increased LSR protein levels. Hepatic total cholesterol, TG, and muscle TG contents were higher in GCE-treated animals as compared to controls, whereas adipose TG levels were unchanged. LSR and LDL-receptor protein levels were correlated with liver total cholesterol, but only LDL-receptor was associated with liver TG. These results show that GCE treatment in mice on a standard chow diet led to significantly increased liver and muscle lipids, with no significant change in adipose tissue TG levels, which should be considered in the long-term use of GCE.

Oral Porphyromonas gingivalis infection affects intestinal microbiota and promotes atherosclerosis

AIM

The link between periodontitis and intestinal dysbiosis, two factors that contribute to atherosclerosis, has not been clearly defined. We investigated the integrative effects of oral infection with Porphyromonas gingivalis (PG), the major pathogen for periodontitis, on intestinal microbiota and atherosclerosis.

MATERIALS AND METHODS

ApoE-/- mice were fed a normal chow diet (NC), a Western diet (WD) or a WD with oral PG infection (PG). The PG infection was investigated by placing a total of 109 CFUs of live PG into the oral cavity of each mouse using a feeding needle five times a week for 3 weeks. Atherosclerotic lesions of the aortae were measured, and blood lipoproteins and the expression of molecules related to lipid metabolism in the liver were analysed. We also performed 16S RNA sequencing and a microbiome analysis using faeces.

RESULTS

En face bloc preparation of the aortae showed that the PG group had a 1.7-fold increase in atherosclerotic lesions compared with the WD group (p < .01). Serum analyses showed that oral PG infection induced a significant decrease in high-density lipoprotein (HDL) and triglyceride. Western blots of hepatic tissue lysates revealed that PG infection reduced the expression of scavenger receptor class B type 1 (SR-B1) in the liver by 50%. Faecal microbiota analysis revealed that species richness estimates (Chao1, ACE) decreased immediately after PG infection. PG infection also induced a significant decrease in Shannon diversity and an increase in Simpson's indices in the WD-fed mice. PG infection significantly increased the phyla Actinobacteria and Deferribacteres, along with the species Mucispirillum schaedleri and Lactobacillus gasseri, in the mice. The functional study showed that PG infection increased the expression of proteins that function in carbohydrate and glucose metabolism, including phosphotransferase system (PTS) proteins and the GntR family transcriptional regulator.

CONCLUSIONS

Oral PG infection promotes atherosclerosis and induces significant metabolic changes, including reduced serum HDL and reduced hepatic SR-B1 and ABCA1 expression, as well as changes in intestinal microbiota. Our study suggests that intestinal dysbiosis accompanies periodontitis and could play a role in atherosclerosis.

Oridonin restores hepatic lipid homeostasis in an LXRα-ATGL/EPT1 axis-dependent manner

Hepatosteatosis is characterized by abnormal accumulation of triglycerides (TG), leading to prolonged and chronic inflammatory infiltration. To date, there is still a lack of effective and economical therapies for hepatosteatosis. Oridonin (ORI) is a major bioactive component extracted from the traditional Chinese medicinal herb Rabdosia rubescens. In this paper, we showed that ORI exerted significant protective effects against hepatic steatosis, inflammation and fibrosis, which was dependent on LXRα signaling. It is reported that LXRα regulated lipid homeostasis between triglyceride (TG) and phosphatidylethanolamine (PE) by promoting ATGL and EPT1 expression. Therefore, we implemented the lipidomic strategy and luciferase reporter assay to verify that ORI contributed to the homeostasis of lipids via the regulation of the ATGL gene associated with TG hydrolysis and the EPT1 gene related to PE synthesis in a LXRα-dependent manner, and the results showed the TG reduction and PE elevation. In detail, hepatic TG overload and lipotoxicity were reversed after ORI treatment by modulating the ATGL and EPT1 genes, respectively. Taken together, the data provide mechanistic insights to explain the bioactivity of ORI in attenuating TG accumulation and cytotoxicity and introduce exciting opportunities for developing novel natural activators of the LXRα-ATGL/EPT1 axis for pharmacologically treating hepatosteatosis and metabolic disorders.

Oat bran prevents high-fat-diet induced muscular dysfunction, systemic inflammation and oxidative stress through reconstructing gut microbiome and circulating metabolome

Western-type diet characterized by high fat emerges a promoter of skeletal muscle dysfunctions. Oat bran was typically considered a healthy food of premium quality for its abundant dietary fiber. The present study comprehensively explored the effects of a diet rich in oat bran on skeletal muscle disfunctions in high-fat diet (HFD) fed mice. Dietary-fiber-rich oat bran significantly ameliorated HFD-induced skeletal muscle function abnormalities, as evidenced by a phenotype improvement in mice grip strength and endurance treadmill running distance, accompanied with the regulation of muscle functions related gene expressions, namely Fis1, Cytc, Mhy2 and Mhy4. Oat bran suppressed the production of systemic inflammatory cytokines while promoted superoxide dismutase and glutathione. Furthermore, oat bran significantly impacted gut microbiota composition by promoting short chain fatty acids (SCFAs) producers and certain probiotic genera, along with the enhancement of SCFAs. Oat bran also significantly decreased the circulating levels of inflammation-related metabolites and played roles in MAPK signaling, thereafter influencing skeletal muscle functions. Collectively, benefits from integration of biomedical indicators, microbiomics, and metabolomics demonstrates the benefits of oat bran consumption on prevention of HFD-related muscular dysfunctions via alleviating HFD-induced inflammation, gut dysbiosis, and systemic metabolism, pinpointing a novel mechanism underlying the muscle-promoting property of oat bran.

A Physiologically Relevant Dose of 50% Egg-Phosphatidylcholine Is Sufficient in Improving Gut Permeability while Attenuating Immune Cell Dysfunction Induced by a High-Fat Diet in Male Wistar Rats

BACKGROUND

Obesity is associated with increased intestinal permeability and a diminished immune response. Phosphatidylcholine (PC), a form of choline found in eggs, has been shown to beneficially modulate T-cell response in the context of obesity when provided as the sole form of choline in the diet.

OBJECTIVE

This study aimed to determine the impact of varying doses of PC as part of a high-fat diet (HFD) on immune cell function and intestinal permeability.

METHODS

Male Wistar rats 4 wk of age were randomly assigned to consume 1 of 6 diets for 12 wk containing the same amount of total choline but differing in the forms of choline: 1-control low-fat (CLF, 20% fat, 100% free choline [FC]); 2-control high-fat (CHF, 50% fat, 100% FC); 3-100% PC (100PC, 50% fat, 100% egg-PC); 4-75% PC (75PC, 50% fat, 75% egg-PC+25% FC); 5-50% PC (50PC, 50% fat, 50% egg-PC+50% FC); and 6-25% PC (25PC; 50% fat, 25% egg-PC+75% FC). Intestinal permeability was measured by fluorescein isothiocyanate-dextran. Immune function was assessed by ex vivo cytokine production of splenocytes and cells isolated from the mesenteric lymph node (MLN) after stimulation with different mitogens.

RESULTS

Feeding the CHF diet increased intestinal permeability compared with the CLF diet, and doses of PC 50% or greater returned permeability to levels similar to that of the CLF diet. Feeding the CHF diet lowered splenocyte production of interleukin (IL)-1β, IL-2, IL-10, and tumor necrosis factor-alpha, and MLN production of IL-2 compared with the CLF group. The 50PC diet most consistently significantly improved cytokine levels (IL-2, IL-10, tumor necrosis factor-alpha) compared with the CHF diet.

CONCLUSIONS

Our results show that a dose of 50% of total choline derived from egg-PC can ameliorate HFD-induced intestinal permeability and immune cell dysfunction.

Mitochondrial electron transport chain, ceramide and Coenzyme Q are linked in a pathway that drives insulin resistance in skeletal muscle

Insulin resistance (IR) is a complex metabolic disorder that underlies several human diseases, including type 2 diabetes and cardiovascular disease. Despite extensive research, the precise mechanisms underlying IR development remain poorly understood. Here, we provide new insights into the mechanistic connections between cellular alterations associated with IR, including increased ceramides, deficiency of coenzyme Q (CoQ), mitochondrial dysfunction, and oxidative stress. We demonstrate that elevated levels of ceramide in the mitochondria of skeletal muscle cells results in CoQ depletion and loss of mitochondrial respiratory chain components, leading to mitochondrial dysfunction and IR. Further, decreasing mitochondrial ceramide levels in vitro and in animal models (under chow and high fat diet) increased CoQ levels and was protective against IR. CoQ supplementation also rescued ceramide-associated IR. Examination of the mitochondrial proteome from human muscle biopsies revealed a strong correlation between the respirasome system and mitochondrial ceramide as key determinants of insulin sensitivity. Our findings highlight the mitochondrial Ceramide-CoQ-respiratory chain nexus as a potential foundation of an IR pathway that may also play a critical role in other conditions associated with ceramide accumulation and mitochondrial dysfunction, such as heart failure, cancer, and aging. These insights may have important clinical implications for the development of novel therapeutic strategies for the treatment of IR and related metabolic disorders.

Retrospective study: risk assessment model for osteoporosis-a detailed exploration involving 4,552 Shanghai dwellers

Background

Osteoporosis, a prevalent orthopedic issue, significantly influences patients' quality of life and results in considerable financial burden. The objective of this study was to develop and validate a clinical prediction model for osteoporosis risk, utilizing computer algorithms and demographic data.

Method

In this research, a total of 4,552 residents from Shanghai were retrospectively included. LASSO regression analysis was executed on the sample's basic characteristics, and logistic regression was employed for analyzing clinical characteristics and building a predictive model. The model's diagnostic capacity for predicting osteoporosis risk was assessed using R software and computer algorithms.

Results

The predictive nomogram model for bone loss risk, derived from the LASSO analysis, comprised factors including BMI, TC, TG, HDL, Gender, Age, Education, Income, Sleep, Alcohol Consumption, and Diabetes. The nomogram prediction model demonstrated impressive discriminative capability, with a C-index of 0.908 (training set), 0.908 (validation set), and 0.910 (entire cohort). The area under the ROC curve (AUC) of the model was 0.909 (training set), 0.903 (validation set), and applicable to the entire cohort. The decision curve analysis further corroborated that the model could efficiently predict the risk of bone loss in patients.

Conclusion

The nomogram, based on essential demographic and health factors (Body Mass Index, Total Cholesterol, Triglycerides, High-Density Lipoprotein, Gender, Age, Education, Income, Sleep, Alcohol Consumption, and Diabetes), offered accurate predictions for the risk of bone loss within the studied population.

Interleukin-13 (IL-13)-A Pleiotropic Cytokine Involved in Wound Healing and Fibrosis

The liver, as a central metabolic organ, is systemically linked to metabolic-inflammatory diseases. In the pathogenesis of the metabolic syndrome, inflammatory and metabolic interactions between the intestine, liver, and adipose tissue lead to the progression of hepatic steatosis to metabolic-dysfunction-associated steatohepatitis (MASH) and consecutive MASH-induced fibrosis. Clinical and animal studies revealed that IL-13 might be protective in the development of MASH through both the preservation of metabolic functions and Th2-polarized inflammation in the liver and the adipose tissue. In contrast, IL-13-associated loss of mucosal gut barrier function and IL-13-associated enhanced hepatic fibrosis may contribute to the progression of MASH. However, there are only a few publications on the effect of IL-13 on metabolic diseases and possible therapies to influence them. In this review article, different aspects of IL-13-associated effects on the liver and metabolic liver diseases, which are partly contradictory, are summarized and discussed on the basis of the recent literature.

HILPDA-mediated lipidomic remodelling promotes radiotherapy resistance in nasopharyngeal carcinoma by accelerating mitophagy

Radiotherapy resistance is a major obstacle to nasopharyngeal carcinoma (NPC) therapy and contributes to tumour recurrence and metastasis. Lipid metabolism is a key regulatory mechanism in cancer biology; however, its role in NPC radiotherapy resistance remains unclear. In this study, we identified hypoxia-inducible lipid droplet-associated protein (HILPDA) as a newly discovered regulator of radioresistance that induces not only lipid droplet (LD) formation but also intracellular lipid remodelling, notably changing mitochondrial cardiolipin (CL) levels. Additionally, we found that the upregulation of CL promotes mitophagy in response to irradiation exposure. Mechanistically, HILPDA inhibits PINK1-mediated CLS1 ubiquitination and degradation. The combination of a mitophagy inhibitor and irradiation significantly increases the radiosensitivity of NPC cells. Human cancer-derived data confirmed that the HILPDA-CLS1 pathway promotes NPC radioresistance. Collectively, these findings suggest that HILPDA plays a critical role in promoting NPC radioresistance and might be targeted to overcome radiotherapeutic resistance in NPC patients in the clinic.

Defensive-lipid droplets: Cellular organelles designed for antimicrobial immunity

Microbes have developed many strategies to subvert host organisms, which, in turn, evolved several innate immune responses. As major lipid storage organelles of eukaryotes, lipid droplets (LDs) are an attractive source of nutrients for invaders. Intracellular viruses, bacteria, and protozoan parasites induce and physically interact with LDs, and the current view is that they "hijack" LDs to draw on substrates for host colonization. This dogma has been challenged by the recent demonstration that LDs are endowed with a protein-mediated antibiotic activity, which is upregulated in response to danger signals and sepsis. Dependence on host nutrients could be a generic "Achilles' heel" of intracellular pathogens and LDs a suitable chokepoint harnessed by innate immunity to organize a front-line defense. Here, we will provide a brief overview of the state of the conflict and discuss potential mechanisms driving the formation of the 'defensive-LDs' functioning as hubs of innate immunity.

Early ART reduces viral seeding and innate immunity in liver and lungs of SIV-infected macaques

Identifying immune cells and anatomical tissues that contribute to the establishment of viral reservoirs is of central importance in HIV-1 cure research. Herein, we used rhesus macaques (RMs) infected with SIVmac251 to analyze viral seeding in the liver and lungs of either untreated or early antiretroviral therapy-treated (ART-treated) RMs. Consistent with viral replication and sensing, transcriptomic analyses showed higher levels of inflammation, pyroptosis, and chemokine genes as well as of interferon-stimulating gene (ISG) transcripts, in the absence of ART. Our results highlighted the infiltration of monocyte-derived macrophages (HLA-DR+CD11b+CD14+CD16+) in inflamed liver and lung tissues associated with the expression of CD183 and CX3CR1 but also with markers of tissue-resident macrophages (CD206+ and LYVE+). Sorting of myeloid cell subsets demonstrated that CD14+CD206-, CD14+CD206+, and CD14-CD206+ cell populations were infected, in the liver and lungs, in SIVmac251-infected RMs. Of importance, early ART drastically reduced viral seeding consistent with the absence of ISG detection but also of genes related to inflammation and tissue damage. Viral DNA was only detected in CD206+HLA-DR+CD11b+ cells in ART-treated RMs. The observation of pulmonary and hepatic viral rebound after ART interruption reinforces the importance of early ART implementation to limit viral seeding and inflammatory reactions.

Raman Imaging Reveals Insights into Membrane Phase Biophysics in Cells

Cellular membranes are essential components of all living organisms. They are composed of a complex mixture of lipids with diverse chemical structures and crucial biological functions. The dynamic and heterogeneous nature of cellular membranes presents a challenge for studying their biophysical properties and organization in vivo. Raman imaging, particularly coherent Raman scattering techniques such as stimulated Raman scattering (SRS) microscopy, have emerged as powerful tools for studying cellular membranes with high spatial and temporal resolution and minimal perturbation. In this Review, we discuss the scientific importance and technical challenges of characterizing membrane composition in cellular contexts and how the advances of Raman imaging can provide unique insights into membrane phase behavior and organization. We also highlight recent applications of Raman imaging in studying cellular membranes and implications in diseases. In particular, the discovery of phase separation and a solid-phase intracellular membrane on endoplasmic reticulum is reviewed in detail, shedding light on the biology of lipotoxicity.

Effect of Omega-3 Rich High-Fat Diet on Markers of Tissue Lipid Metabolism in Glucocorticoid-Treated Mice

Glucocorticoids (GCs) are some of the most widely prescribed therapies for treating numerous inflammatory diseases and multiple cancer types. With chronic use, GCs' therapeutic benefits are concurrent with deleterious metabolic side effects, which worsen when combined with a high-fat diet (HFD). One characteristic of the common Western HFD is the presence of high omega-6 polyunsaturated fatty acids (PUFAs) and a deficiency in omega-3 PUFAs. The aim of this experiment was to determine whether fat composition resulting from HFD affects glucocorticoid-induced alterations in lipid-handling by the liver and skeletal muscle. Male wild-type C57BL/6 mice were randomized into two groups: n-6 (45% fat 177.5 g lard) and n-3 (45% fat 177.5 g Menhaden oil). After 4 weeks on their diets, groups were divided to receive either daily injections of dexamethasone (3 mg/kg/day) or sterile PBS for 1 week while continuing diets. The n-3 HFD diet attenuated adipose and hepatic fatty accumulation and prevented GC-induced increases in liver lipid metabolism markers Cd36 and Fabp. N-3 HFD had little effect on markers of lipid metabolism in oxidative and glycolytic skeletal muscle and was unable to attenuate GC-induced gene expression in the muscle. The present study's result demonstrated that the change of fat composition in HFD could beneficially alter the fatty acid accumulation and associated lipid metabolism markers in mice treated with dexamethasone.

The relationship and interaction between triglyceride glucose index and obesity in the risk of prehypertension population: a cross-sectional study from a survey in Anhui, Eastern China

BACKGROUND

The triglyceride glucose (TyG) index has been regarded as an effective proxy of Insulin resistance (IR). Studies on the TyG index, obesity and the risk of prehypertension (PHT) in elderly people are not apparent currently. The study sought to investigate the predictive value of TyG index and the associations with PHT risk and obesity.

METHODS

A community-based cross-sectional study was conducted in Bengbu City, Anhui province, China. Participants older than 65 years accepted questionnaire surveys, physical examinations and blood biochemistry tests. Based on the testing results, indicators including BMI (body mass index), WC (waist circumference), WHtR (waist-to-height-ratio), LAP(Lipid accumulation products) and TyG were calculated. Residents were classified into quartiles by their TyG indexes. Receiver operating characteristic curve (ROC) analysis was carried out to predict obesity indices for PHT. The three additive interaction indicators, RERI (relative excess risk due to interaction), AP (attributable proportion due to interaction) and S (synergy index) were used to assess the interaction impacts.

RESULTS

Two thousand six hundred sixty-six eligible elderly people were included in study and the prevalence of PHT was 71.04% (n = 1894). With increasing TyG index quartile, PHT became more prevalent. After adjusting for confounding factors, the prevalence of PHT risk with TyG levels in the fourth quartile (Q4, male: 2.83, 95%CI: 1.77-4.54; female: 2.75, 95%CI:1.91-3.97) was greater than that in the first quartile (Q1:ref). TyG index (AUC: 0.626, 95%CI: 0.602 to 0.650) was superior than BMI (AUC: 0.609, 95%CI: 0.584 to 0.633) in predicting PHT among females. Eventually, there were significant interactions of TyG index with obesity in males (General obesity: AP = 0.87, 95%CI: 0.72 to 1.02, S = 10.48, 95%CI: 3.43 to 31.97; Abdominal obesity: AP = 0.60,95%CI: 0.38 to 0.83, S = 3.53, 95%CI: 1.99 to 6.26) and females (General obesity: AP = 0.89, 95%CI: 0.79 to 0.98, S = 12.46, 95%CI: 5.61 to 27.69; Abdominal obesity: AP = 0.66, 95%CI: 0.51 to 0.82, S = 3.89, 95%CI:2.54 to 5.98).

CONCLUSION

TyG index and PHT risk are tightly correlated. The risk of chronic disease in the elderly can be decreased by early detection of PHT utilizing the TyG index. In this research, the TyG index was more predictable than other indicators of obesity.

FUNDC1 modulates mitochondrial defects and pancreatic β-cell dysfunction under lipotoxicity

Insulin resistance and many metabolic disorders are causally linked to mitochondrial dysfunction or defective mitochondrial quality control. Mitophagy is a highly selective mechanism that recognizes and removes damaged mitochondria to maintain mitochondrial homeostasis. Here, we addressed the potential role of FUNDC1, a mediator of mitophagy, in pancreatic β-cell dysfunction under lipotoxicity. In pancreatic MIN6 cells, FUNDC1 deficiency aggravated palmitate-induced mitochondrial dysfunction, which led to cell death and insulin insensitivity. Interestingly, FUNDC1 overexpression prevented these cellular harms brought on by palmitate. In mice models, pancreatic-specific FUNDC1 overexpression alleviated high-fat diet (HFD)-induced insulin resistance and obesity. Mechanistically, pancreatic-specific overexpression of FUNDC1 ameliorated mitochondrial defects and endoplasmic reticulum (ER) stress upon HFD. Our research indicates that FUNDC1 plays an essential role in apoptosis and dysfunction of pancreatic β-cells via modulating lipotoxicity-induced mitochondrial defects.

Obesity, non-alcoholic fatty liver disease and hepatocellular carcinoma: current status and therapeutic targets

Obesity is a global epidemic and overwhelming evidence indicates that it is a risk factor for numerous cancers, including hepatocellular carcinoma (HCC), the third leading cause of cancer-related deaths worldwide. Obesity-associated hepatic tumorigenesis develops from nonalcoholic fatty liver disease (NAFLD), progressing to nonalcoholic steatohepatitis (NASH), cirrhosis and ultimately to HCC. The rising incidence of obesity is resulting in an increased prevalence of NAFLD and NASH, and subsequently HCC. Obesity represents an increasingly important underlying etiology of HCC, in particular as the other leading causes of HCC such as hepatitis infection, are declining due to effective treatments and vaccines. In this review, we provide a comprehensive overview of the molecular mechanisms and cellular signaling pathways involved in the pathogenesis of obesity-associated HCC. We summarize the preclinical experimental animal models available to study the features of NAFLD/NASH/HCC, and the non-invasive methods to diagnose NAFLD, NASH and early-stage HCC. Finally, since HCC is an aggressive tumor with a 5-year survival of less than 20%, we will also discuss novel therapeutic targets for obesity-associated HCC and ongoing clinical trials.

Targeting HMG-CoA synthase 2 suppresses tamoxifen-resistant breast cancer growth by augmenting mitochondrial oxidative stress-mediated cell death

AIMS

In this study, we aimed to investigate previously unrecognized lipid metabolic perturbations in tamoxifen-resistant breast cancer (BC) by conducting comprehensive metabolomics and transcriptomics analysis. We identified the role of 3-hydroxy-3-methylglutary-coenzyme-A-synthase 2 (HMGCS2), a key enzyme responsible for ketogenesis, in tamoxifen-resistant BC growth.

MAIN METHODS

Comprehensive metabolomics (CE-TOFMS, LC-TOFMS) and transcriptiomics analysis were performed to characterize metabolic pathways in tamoxifen-resistant BC cells. The upregulation of HMGCS2 were verified thorugh immunohistochemistry (IHC) in clinical samples obtained from patients with recurrent BC. HMGCS2 inhibitor was discovered through surface plasmon resonance analysis, enzyme assay, and additional molecular docking studies. The effect of HMGCS2 suppression on tumor growth was studied thorugh BC xenograft model, and intratumoral lipid metabolites were analyzed via MALDI-TOFMS imaging.

KEY FINDINGS

We revealed that the level of HMGCS2 was highly elevated in both tamoxifen-resistant T47D sublines (T47D/TR) and clinical refractory tumor specimens from patients with ER+ breast cancer, who had been treated with adjuvant tamoxifen. Suppression of HMGCS2 in T47D/TR resulted in the accumulation of mitochondrial reactive oxygen species (mtROS) and apoptotic cell death. Further, we identified alphitolic acid, a triterpenoid natural product, as a novel HMGCS2-specific inhibitor that elevated mtROS levels and drastically retarded the growth of T47D/TR in in vitro and in vivo experiments.

SIGNIFICANCE

Enhanced ketogenesis with upregulation of HMGCS2 is a potential metabolic vulnerability of tamoxifen-resistant BC that offers a new therapeutic opportunity for treating patients with ER+ BC that are refractory to tamoxifen treatment.

Association of triglyceride/high-density lipoprotein cholesterol ratio with severe complications of COVID-19

Background

The coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 virus can lead to serious complications such as respiratory failure, requiring mechanical ventilation or ICU care, and can even result in death, especially in older patients with comorbidities. The ratio of triglyceride to high-density lipoprotein cholesterol (TG/HDL), a biomarker of atherosclerotic dyslipidemia and insulin resistance, is related to cardiovascular mortality and morbidity. We aimed to evaluate the link between serious complications of COVID-19 and TG/HDL in the general population.

Methods

We conducted a comprehensive analysis of 3,933 COVID-19 patients from a nationwide cohort in Korea spanning from January 1 to June 4, 2020. TG/HDL ratio was calculated from the national health screening examination data underwent before the COVID-19 infection. Serious complications of COVID-19 were defined as a composite of high-flow oxygen therapy, mechanical ventilation, admission to the intensive care unit (ICU), and mortality. We employed logistic regression analysis to investigate the relationship between the TG/HDL ratio and the likelihood of developing severe complications within 2 months of the diagnosis. To visualize this association, we used a smoothing spline plot based on the generalized additive regression model. Multivariate analysis was performed with adjustment for age, gender, body mass index, lifestyle measures, and comorbidities.

Results

Among the 3,933 COVID-19 patients, the proportion of serious complications was 7.53%. Regarding individual outcomes, the number of patients who received high-flow oxygen therapy, mechanical ventilation, ICU care, and died was 84 (2.14%), 122 (3.10%), 173 (4.40%), and 118 (3.00%), respectively. In the multivariable logistic regression, a positive association was found between TG/HDL ratio and serious complications of COVID-19 (adjusted OR, 1.09; 95% CI [1.03-1.15], p = 0.004).

Conclusion

Our study revealed a significant positive association between TG/HDL ratio and the risk of developing severe complications in COVID-19-infected patients. While this finding provides valuable insight into the potential prognostic role of TG/HDL ratio in COVID-19, further studies are needed to fully elucidate the underlying mechanisms behind this relationship.

Linking the unfolded protein response to bioactive lipid metabolism and signalling in the cell non-autonomous extracellular communication of ER stress

The endoplasmic reticulum (ER) organelle is the key intracellular site of both protein and lipid biosynthesis. ER dysfunction, termed ER stress, can result in protein accretion within the ER and cell death; a pathophysiological process contributing to a range of metabolic diseases and cancers. ER stress leads to the activation of a protective signalling cascade termed the Unfolded Protein Response (UPR). However, chronic UPR activation can ultimately result in cellular apoptosis. Emerging evidence suggests that cells undergoing ER stress and UPR activation can release extracellular signals that can propagate UPR activation to target tissues in a cell non-autonomous signalling mechanism. Separately, studies have determined that the UPR plays a key regulatory role in the biosynthesis of bioactive signalling lipids including sphingolipids and ceramides. Here we weigh the evidence to combine these concepts and propose that during ER stress, UPR activation drives the biosynthesis of ceramide lipids, which are exported and function as cell non-autonomous signals to propagate UPR activation in target cells and tissues.

Ormdl3 regulation of specific ceramides is dispensable for mouse β-cell function and glucose homeostasis under obesogenic conditions

Chronic elevation of sphingolipids contributes to β-cell failure. ORMDL3 has been identified as a key regulator of sphingolipid homeostasis, however, its function in pancreatic β-cell pathophysiology remains unclear. Here, we generated a mouse model lacking Ormdl3 within pancreatic β-cells (Ormdl3 β-/-). We show that loss of β-cell Ormdl3 does not alter glucose tolerance, insulin sensitivity, insulin secretion, islet morphology, or cellular ceramide levels on standard chow diet. When challenged with a high fat diet, while Ormdl3 β-/- mice did not exhibit any alteration in metabolic parameters or islet architecture, lipidomics analysis revealed significantly higher levels of very long chain ceramides in their islets. Taken together, our results reveal that loss of Ormdl3 alone is not sufficient to impinge upon β-cell function or whole-body glucose and insulin homeostasis, however, β-cell-specific loss of Ormdl3 does significantly alter levels of specific sphingolipid species in islets upon high fat feeding.

Saturated fatty acids increase LPI to reduce FUNDC1 dimerization and stability and mitochondrial function

Ectopic lipid deposition and mitochondrial dysfunction are common etiologies of obesity and metabolic disorders. Excessive dietary uptake of saturated fatty acids (SFAs) causes mitochondrial dysfunction and metabolic disorders, while unsaturated fatty acids (UFAs) counterbalance these detrimental effects. It remains elusive how SFAs and UFAs differentially signal toward mitochondria for mitochondrial performance. We report here that saturated dietary fatty acids such as palmitic acid (PA), but not unsaturated oleic acid (OA), increase lysophosphatidylinositol (LPI) production to impact on the stability of the mitophagy receptor FUNDC1 and on mitochondrial quality. Mechanistically, PA shifts FUNDC1 from dimer to monomer via enhanced production of LPI. Monomeric FUNDC1 shows increased acetylation at K104 due to dissociation of HDAC3 and increased interaction with Tip60. Acetylated FUNDC1 can be further ubiquitinated by MARCH5 for proteasomal degradation. Conversely, OA antagonizes PA-induced accumulation of LPI, and FUNDC1 monomerization and degradation. A fructose-, palmitate-, and cholesterol-enriched (FPC) diet also affects FUNDC1 dimerization and promotes its degradation in a non-alcoholic steatohepatitis (NASH) mouse model. We thus uncover a signaling pathway that orchestrates lipid metabolism with mitochondrial quality.

[Role of metaflammation as a systemic manifestation of metabolic diseases]

Visceral obesity as a component of the metabolic syndrome is characterized by systemic and local inflammation, which can be quantified in organs (metaflammation). This process can be regarded as a chronic, sterile, and low-grade state of inflammation without infection, trauma, tumor or autoimmunity. It is caused by an inflammation of the visceral adipose tissue (adipose inflammation or adipoflammation) due to adipocyte hypertrophy and hyperplasia with increased infiltration by monocytes and macrophages. Important is the presence of proinflammatory, so-called polarized M1 macrophages that are induced by interferon gamma (IFN-γ) and lipopolysaccharides (LPS) with secretion of interleukin (IL)-6, tumor necrosis factor (TNF) and IL‑1. In contrast, the anti-inflammatory, so-called polarized M2 macrophages induced by IL‑4 and IL-13 with secretion of IL‑8 and IL-10 decrease. In addition, the secreted adipokine pattern changes from anti-inflammatory to proinflammatory. Adipocyte necrosis, local hypoxia, dysregulated autophagy, activation of inflammasomes, modulation of toll-like receptors, and epigenetic factors play a complex role. This mechanism results in local insulin resistance and subsequently a systemic insulin resistance of peripheral organs as well as a spillover of local mediators of inflammation into the systemic circulation (measured as obesity C‑reactive protein, CRP). The activation of inflammatory signal transduction cascades leads to inhibitory phosphorylation of the insulin signaling pathway and a weakening of the effect of insulin. In parallel, ectopic lipid accumulation occurs in the liver, musculature, pancreas, pericardium and lungs. Diacylglycerol (DAG) activates specific isoforms of protein kinase C (ε in the liver and τ in the musculature), which in turn lead to inhibition of the insulin signaling pathway. Insulin resistance in obesity and type 2 diabetes mellitus is an inflammatory disease. The aim of future translational approaches is an anti-inflammatory, molecularly individualized (precision medicine) treatment in adipose tissue (targeted therapy) and in organs of insulin resistance.

A role of STING signaling in obesity-induced lung inflammation

BACKGROUND

It is established that pulmonary disorders are comorbid with metabolic disorders such as obesity. Previous studies show that the stimulator of interferon genes (STING) signaling plays crucial roles in obesity-induced chronic inflammation via TANK-binding kinase 1 (TBK1) pathways. However, it remains unknown whether and how the STING signaling is implicated in the inflammatory processes in the lung in obesity.

METHODS

Human lung tissues were obtained from obese patients (n = 3) and controls (n = 3). Mice were fed with the high-fat diet or regular control diet to establish the diet-induced obese (DIO) and lean mice, and were treated with C-176 (a specific STING inhibitor) or vehicle respectively. The lung macrophages were exposed to palmitic acid (PA) in vitro. The levels of STING singaling and metabolic inflammation factors were detected and anlyzed.

RESULTS

We find that STING+/CD68+ macrophages are increased in lung tissues in patients with obesity. Our data also show that the expressions of STING and the levels of proinflammatory cytokines are increased both in lung tissues and bronchoalveolar lavage fluid (BALF) in obesity compared to controls, and inhibition of the STING blunted the obesity-induced lung inflammation. Mechanistically, our data demonstrate that the STING signaling pathway is involved in the PA-induced inflammation through the STING-TBK1-IRF3 (interferon regulatory factor 3)/NF-κB (nuclear factor kappa B) pathways in the lung macrophages.

CONCLUSIONS

Our results collectively suggest that the STING signaling contributes to obesity-associated inflammation by stimulating proinflammatory processes in lung macrophages, one that may serve as a therapeutic target in ameliorating obesity-related lung dysfunctions.

Lipid Aldehydes 4-Hydroxynonenal and 4-Hydroxyhexenal Exposure Differentially Impact Lipogenic Pathways in Human Placenta

Long chain polyunsaturated fatty acids (LCPUFAs), such as the omega-6 (n-6) arachidonic acid (AA) and n-3 docosahexanoic acid (DHA), have a vital role in normal fetal development and placental function. Optimal supply of these LCPUFAs to the fetus is critical for improving birth outcomes and preventing programming of metabolic diseases in later life. Although not explicitly required/recommended, many pregnant women take n-3 LCPUFA supplements. Oxidative stress can cause these LCPUFAs to undergo lipid peroxidation, creating toxic compounds called lipid aldehydes. These by-products can lead to an inflammatory state and negatively impact tissue function, though little is known about their effects on the placenta. Placental exposure to two major lipid aldehydes, 4-hydroxynonenal (4-HNE) and 4-hydroxyhexenal (4-HHE), caused by peroxidation of the AA and DHA, respectively, was examined in the context of lipid metabolism. We assessed the impact of exposure to 25 μM, 50 μM and 100 μM of 4-HNE or 4-HHE on 40 lipid metabolism genes in full-term human placenta. 4-HNE increased gene expression associated with lipogenesis and lipid uptake (ACC, FASN, ACAT1, FATP4), and 4-HHE decreased gene expression associated with lipogenesis and lipid uptake (SREBP1, SREBP2, LDLR, SCD1, MFSD2a). These results demonstrate that these lipid aldehydes differentially affect expression of placental FA metabolism genes in the human placenta and may have implications for the impact of LCPUFA supplementation in environments of oxidative stress.

A Longitudinal Study in Turkiye of Host Ability to Produce Antibodies following a Third Homologous BNT162b2 Vaccination

Obesity is a multifaceted, complex condition that has negative impacts on one's health. There are conflicting reports regarding the COVID-19 vaccine's ability to induce antibody formation in obese people. Our study aimed to determine anti-S-RBD IgG and surrogate neutralizing antibody (snAb) levels before and after the third Pfizer-BioNTech (BNT162b2) vaccination (at 15, 60, 90, and 120 days) in normal-weight adults, overweight, and obese individuals without any comorbidity or previous SARS-CoV-2 infection history, but it did not evaluate the response to the first two doses. In this longitudinal prospective study in Istanbul, Turkey, a total of 323 consecutive adult individuals (141 normal weight, 108 overweight, and 74 patients with obesity) were included. Peripheral blood samples were collected. Anti-S-RBD IgG and surrogate neutralizing antibody levels were detected using the ELISA method. After the third dose of BNT162b2 vaccination, obese patients had significantly lower levels of snAb against SARS-CoV-2 compared with normal-weight controls, but the levels otherwise did not differ between the study groups. Across all individuals in our cohort, titers peaked about a month after this third vaccination and then gradually faded. Anti-S-RBD IgG and snAb IH% levels against SARS-CoV-2 were not correlated with IL-6 and TNF-α levels. In conclusion, anti-S-RBD IgG titers and snAb IH% levels against SARS-CoV-2 were determined longitudinally for 120 days after the third homologous BNT162b2 vaccination. Although there were no significant differences in anti-S-RBD IgG, we found significant differences in the snAb IH% levels against SARS-CoV-2 between obese and healthy control subjects.

Role of immune responses for development of NAFLD-associated liver cancer and prospects for therapeutic modulation

The liver is the central metabolic organ of the body regulating energy and lipid metabolism and at the same time has potent immunological functions. Overwhelming the metabolic capacity of the liver by obesity and sedentary lifestyle leads to hepatic lipid accumulation, chronic necro-inflammation, enhanced mitochondrial/ER-stress and development of non-alcoholic fatty liver disease (NAFLD), with its pathologic form nonalcoholic steatohepatitis (NASH). Based on knowledge on pathophysiological mechanisms, specifically targeting metabolic diseases to prevent or slow down progression of NAFLD to liver cancer will become possible. Genetic/environmental factors contribute to development of NASH and liver cancer progression. The complex pathophysiology of NAFLD-NASH is reflected by environmental factors, particularly the gut microbiome and its metabolic products. NAFLD-associated HCC occurs in most of the cases in the context of a chronically inflamed liver and cirrhosis. Recognition of environmental alarmins or metabolites derived from the gut microbiota and the metabolically injured liver create a strong inflammatory milieu supported by innate and adaptive immunity. Several recent studies indicate that the chronic hepatic microenvironment of steatosis induces auto-aggressive CD8+CXCR6+PD1+ T cells secreting TNF and upregulating FasL to eliminate parenchymal and non-parenchymal cells in an antigen independent manner. This promotes chronic liver damage and a pro-tumorigenic environment. CD8+CXCR6+PD1+ T cells possess an exhausted, hyperactivated, resident phenotype and trigger NASH to HCC transition, and might be responsible for a less efficient treatment response to immune-check-point inhibitors - in particular atezolizumab/bevacizumab. Here, we provide an overview of NASH-related inflammation/pathogenesis focusing on new discoveries on the role of T cells in NASH-immunopathology and therapy response. This review discusses preventive measures to halt disease progression to liver cancer and therapeutic strategies to manage NASH-HCC patients.

Immunometabolic rewiring in long COVID patients with chronic headache

Almost 20% of patients with COVID-19 experience long-term effects, known as post-COVID condition or long COVID. Among many lingering neurologic symptoms, chronic headache is the most common. Despite this health concern, the etiology of long COVID headache is still not well characterized. Here, we present a longitudinal multi-omics analysis of blood leukocyte transcriptomics, plasma proteomics and metabolomics of long COVID patients with chronic headache. Long COVID patients experienced a state of hyper-inflammation prior to chronic headache onset and maintained persistent inflammatory activation throughout the progression of chronic headache. Metabolomic analysis also revealed augmented arginine and lipid metabolisms, skewing towards a nitric oxide-based pro-inflammation. Furthermore, metabolisms of neurotransmitters including serotonin, dopamine, glutamate, and GABA were markedly dysregulated during the progression of long COVID headache. Overall, these findings illustrate the immuno-metabolomics landscape of long COVID patients with chronic headache, which may provide insights to potential therapeutic interventions.

Challenges and opportunities in NASH drug development

Nonalcoholic fatty liver disease (NAFLD) and its more severe form, nonalcoholic steatohepatitis (NASH), represent a growing worldwide epidemic and a high unmet medical need, as no licensed drugs have been approved thus far. Currently, histopathological assessment of liver biopsies is mandatory as a primary endpoint for conditional drug approval. This requirement represents one of the main challenges in the field, as there is substantial variability in this invasive histopathological assessment, which leads to dramatically high screen-failure rates in clinical trials. Over the past decades, several non-invasive tests have been developed to correlate with liver histology and, eventually, outcomes to assess disease severity and longitudinal changes non-invasively. However, further data are needed to ensure their endorsement by regulatory authorities as alternatives to histological endpoints in phase 3 trials. This Review describes the challenges of drug development in NAFLD-NASH trials and potential mitigating strategies to move the field forward.