Plasma lipidomic analysis reveals strong similarities between lipid fingerprints in human, hamster and mouse compared to other animal species

The adipocyte apolipoprotein M is negatively associated with inflammation

Obesity is associated with the development of local adipose tissue (AT) and systemic inflammation. Most adipokines are upregulated with obesity and have pro-inflammatory properties. Few are downregulated and possess beneficial anti-inflammatory effects. The apolipoprotein M (APOM) is an adipokine whose expression is low during obesity and associated with a metabolically healthy AT. Here, the role of adipose-derived APOM on obesity-associated AT inflammation was investigated by measuring the expression of pro-inflammatory genes in human and mouse models. In 300 individuals with obesity, AT APOM mRNA level was negatively associated with plasma hs-CRP. The inflammatory profile was assessed in Apom-/- and WT mice fed a normal chow diet (NCD), or a high-fat diet (HFD) to induce AT inflammation. After HFD, mice had a higher inflammatory profile in AT and liver, and a 50% lower Apom gene expression compared with NCD-fed mice. Apom deficiency was associated with a higher inflammatory signature in AT compared with WT mice but not in the liver. Adeno-associated viruses encoding human APOM were used to induce APOM overexpression: in vivo, in WT mice AT prior to HFD; in vitro, in human adipocytes which conditioned media was applied to ThP-1 macrophages. The murine AT overexpressing APOM gene had a reduced inflammatory profile. The macrophages treated with APOM-enriched media from adipocytes exhibited lower IL6 and MCP1 gene expression compared with macrophages treated with control media, independently of S1P. Our study highlights the protective role of adipocyte APOM against obesity-induced AT inflammation.

Sphingolipids and Chronic Kidney Disease

Sphingolipids (SLs) are bioactive signaling molecules essential for various cellular processes, including cell survival, proliferation, migration, and apoptosis. Key SLs such as ceramides, sphingosine, and their phosphorylated forms play critical roles in cellular integrity. Dysregulation of SL levels is implicated in numerous diseases, notably chronic kidney disease (CKD). This review focuses on the role of SLs in CKD, highlighting their potential as biomarkers for early detection and prognosis. SLs maintain renal function by modulating the glomerular filtration barrier, primarily through the activity of podocytes. An imbalance in SLs can lead to podocyte damage, contributing to CKD progression. SL metabolism involves complex enzyme-catalyzed pathways, with ceramide serving as a central molecule in de novo and salvage pathways. Ceramides induce apoptosis and are implicated in oxidative stress and inflammation, while sphingosine-1-phosphate (S1P) promotes cell survival and vascular health. Studies have shown that SL metabolism disorders are linked to CKD progression, diabetic kidney disease, and glomerular diseases. Targeting SL pathways could offer novel therapeutic approaches for CKD. This review synthesizes recent research on SL signaling regulation in kidney diseases, emphasizing the importance of maintaining SL balance for renal health and the potential therapeutic benefits of modulating SL pathways.

Parallel Evolution at the Regulatory Base-Pair Level Contributes to Mammalian Interspecific Differences in Polygenic Traits

Parallel evolution occurs when distinct lineages with similar ancestral states converge on a new phenotype. Parallel evolution has been well documented at the organ, gene pathway, and amino acid sequence level but in theory, it can also occur at individual nucleotides within noncoding regions. To examine the role of parallel evolution in shaping the biology of mammalian complex traits, we used data on single-nucleotide polymorphisms (SNPs) influencing human intraspecific variation to predict trait values in other species for 11 complex traits. We found that the alleles at SNP positions associated with human intraspecific height and red blood cell (RBC) count variation are associated with interspecific variation in the corresponding traits across mammals. These associations hold for deeper branches of mammalian evolution as well as between strains of collaborative cross mice. While variation in RBC count between primates uses both ancient and more recently evolved genomic regions, we found that only primate-specific elements were correlated with primate body size. We show that the SNP positions driving these signals are flanked by conserved sequences, maintain synteny with target genes, and overlap transcription factor binding sites. This work highlights the potential of conserved but tunable regulatory elements to be reused in parallel to facilitate evolutionary adaptation in mammals.

Comparative studies between humans and golden Syrian hamsters via thromboelastography

BACKGROUND

Thromboelastography (TEG) is a widely utilized clinical testing method for real-time monitoring of platelet function and the thrombosis process. Lipid metabolism disorders are crucial risk factors for thrombosis. The lipid metabolism characteristics of hamsters resemble those of humans more closely than mice and rats, and their relatively large blood volume makes them suitable for studying the mechanisms of thrombosis related to plasma lipid mechanisms. Whole blood samples from golden Syrian hamsters and healthy humans were obtained following standard clinical procedures. TEG was employed to evaluate coagulation factor function, fibrinogen (Fib) function, platelet function, and the fibrinolytic system.

METHODS

The whole blood from hamster or healthy human was isolated following the clinical procedure, and TEG was employed to evaluate the coagulation factor function, Fib function, platelet function, and fibrinolytic system. Coagulation analysis used ACLTOP750 automatic coagulation analysis pipeline. Blood routine testing used XN-2000 automatic blood analyzer.

RESULTS

TEG parameters revealed that hamsters exhibited stronger coagulation factor function than humans (reaction time [R], p = 0.0117), with stronger Fib function (alpha angle, p < 0.0001; K-time [K], p < 0.0001). Platelet function did not differ significantly (maximum amplitude [MA], p = 0.077). Hamsters displayed higher coagulation status than humans (coagulation index [CI], p = 0.0023), and the rate of blood clot dissolution in hamsters differed from that in humans (percentage lysis 30 min after MA, p = 0.02). Coagulation analysis parameters indicated that prothrombin time (PT) and activated partial thromboplastin time (APTT) were faster in hamsters than in humans (PT, p = 0.0014; APTT, p = 0.03), whereas the Fib content was significantly lower in hamsters than in humans (p < 0.0001). No significant difference was observed in thrombin time (p = 0.1949).

CONCLUSIONS

In summary, TEG could be used to evaluate thrombosis and bleeding parameters in whole blood samples from hamsters. The platelet function of hamsters closely resembled that of humans, whereas their coagulation function was significantly stronger.

A hamster model for stress-induced weight gain

This review addresses the translational relevance of animal models of stress and their effects on body weight. In humans, stress, whether chronic or acute, has often been associated with increased food intake and weight gain. In view of the current obesity epidemic, this phenomenon is especially relevant. Such observations contrast with reports with commonly used laboratory animals, especially rats and mice. In these species, it is common to find individuals gaining less weight under stress, even with potent social stressors. However, there are laboratory species that present increased appetite and weight gain under stress, such as golden hamsters. Furthermore, these animals also include metabolic and behavioral similarities with humans, including hoarding behavior which is also enhanced under stress. Consequently, we propose that our comparative perspective provides useful insights for future research on the development of obesity in humans as a consequence of chronic stress exposure.

Extracellular Vesicle and Lipoprotein Interactions

Extracellular vesicles and lipoproteins are lipid-based biological nanoparticles that play important roles in (patho)physiology. Recent evidence suggests that extracellular vesicles and lipoproteins can interact to form functional complexes. Such complexes have been observed in biofluids from healthy human donors and in various in vitro disease models such as breast cancer and hepatitis C infection. Lipoprotein components can also form part of the biomolecular corona that surrounds extracellular vesicles and contributes to biological identity. Potential mechanisms and the functional relevance of extracellular vesicle-lipoprotein complexes remain poorly understood. This Review addresses the current knowledge of the extracellular vesicle-lipoprotein interface while drawing on pre-existing knowledge of liposome interactions with biological nanoparticles. There is an urgent need for further research on the lipoprotein-extracellular vesicle interface, which could return important mechanistic, therapeutic, and diagnostic findings.

Effect of combined administration of Acyl-CoA: Cholesterol acyltransferase 1 inhibitor and glucagon-like peptide 1 receptor agonist on a rodent model of diet-induced obesity

A glucagon-like peptide 1 receptor agonist (GLP-1 RA) semaglutide was approved for the treatment of obesity by the Food and Drug Administration. However, it can cause gastrointestinal events at high doses, limiting its broader use. Combining drugs with multiple mechanisms of action could enhance the weight-reducing effects while minimizing side effects. To this end, we investigated the combined effects of semaglutide and avasimibe, an acyl-CoA:cholesterol acyltransferase 1 (ACAT1) inhibitor, on weight reduction in diet-induced obesity mice. Two cohorts of mice were used: In cohort 1, mice were fed a high-fat (HF) diet for 12 weeks and then randomly assigned to the vehicle, avasimibe [10 mg/kg body weight (BW)], semaglutide (0.4 mg/kg BW), or combination groups. The drugs were administered via subcutaneous (sc) injections on a daily basis. In cohort 2, mice were fed an HF diet for 8 weeks and randomly assigned to the same four groups, but avasimibe was administered at a dose of 20 mg/kg BW, and the drugs were administered every 3 days. In cohort 1, semaglutide initially reduced food intake initially, but this effect was diminished with prolonged administration. Avasimibe, on the other hand, did not affect food intake but prevented weight gain to a lesser extent than semaglutide. Importantly, the combination treatment resulted in the greatest percentage of body weight reduction, along with lower plasma glucose and leptin levels compared to the semaglutide single-treatment group. Cohort 2 confirmed that the superior weight loss in the combination group compared to the other three groups was largely due to a significant reduction in fat mass. Histological analysis of inguinal adipose tissue showed smaller adipocyte size across all treatment groups compared to the vehicle group, with no significant differences among the treatment groups. Collectively, these findings suggest combining semaglutide and avasimibe could be an effective approach to weight management.

Raman Spectroscopy Spectral Fingerprints of Biomarkers of Traumatic Brain Injury

Traumatic brain injury (TBI) affects millions of people of all ages around the globe. TBI is notoriously hard to diagnose at the point of care, resulting in incorrect patient management, avoidable death and disability, long-term neurodegenerative complications, and increased costs. It is vital to develop timely, alternative diagnostics for TBI to assist triage and clinical decision-making, complementary to current techniques such as neuroimaging and cognitive assessment. These could deliver rapid, quantitative TBI detection, by obtaining information on biochemical changes from patient's biofluids. If available, this would reduce mis-triage, save healthcare providers costs (both over- and under-triage are expensive) and improve outcomes by guiding early management. Herein, we utilize Raman spectroscopy-based detection to profile a panel of 18 raw (human, animal, and synthetically derived) TBI-indicative biomarkers (N-acetyl-aspartic acid (NAA), Ganglioside, Glutathione (GSH), Neuron Specific Enolase (NSE), Glial Fibrillary Acidic Protein (GFAP), Ubiquitin C-terminal Hydrolase L1 (UCHL1), Cholesterol, D-Serine, Sphingomyelin, Sulfatides, Cardiolipin, Interleukin-6 (IL-6), S100B, Galactocerebroside, Beta-D-(+)-Glucose, Myo-Inositol, Interleukin-18 (IL-18), Neurofilament Light Chain (NFL)) and their aqueous solution. The subsequently derived unique spectral reference library, exploiting four excitation lasers of 514, 633, 785, and 830 nm, will aid the development of rapid, non-destructive, and label-free spectroscopy-based neuro-diagnostic technologies. These biomolecules, released during cellular damage, provide additional means of diagnosing TBI and assessing the severity of injury. The spectroscopic temporal profiles of the studied biofluid neuro-markers are classed according to their acute, sub-acute, and chronic temporal injury phases and we have further generated detailed peak assignment tables for each brain-specific biomolecule within each injury phase. The intensity ratios of significant peaks, yielding the combined unique spectroscopic barcode for each brain-injury marker, are compared to assess variance between lasers, with the smallest variance found for UCHL1 (σ2 = 0.000164) and the highest for sulfatide (σ2 = 0.158). Overall, this work paves the way for defining and setting the most appropriate diagnostic time window for detection following brain injury. Further rapid and specific detection of these biomarkers, from easily accessible biofluids, would not only enable the triage of TBI, predict outcomes, indicate the progress of recovery, and save healthcare providers costs, but also cement the potential of Raman-based spectroscopy as a powerful tool for neurodiagnostics.

"Humanizing" mouse environments: Humidity, diurnal cycles and thermoneutrality

Thermoneutral housing has been shown to promote more accurate and robust development of several pathologies in mice. Raising animal housing temperatures a few degrees may create a relatively straightforward opportunity to improve translatability of mouse models. In this commentary, we discuss the changes of physiology induced in mice housed at thermoneutrality, and review techniques for measuring systemic thermogenesis, specifically those affecting storage and mobilization of lipids in adipose depots. Environmental cues are a component of the information integrated by the brain to calculate food consumption and calorie deposition. We show that relative humidity is one of those cues, inducing a rapid sensory response that is converted to a more chronic susceptibility to obesity. Given high inter-institutional variability in the regulation of relative humidity, study reproducibility may be improved by consideration of this factor. We evaluate a "humanized" environmental cycling protocol, where mice sleep in warm temperature housing, and are cool during the wake cycle. We show that this protocol suppresses adaptation to cool exposure, with consequence for adipose-associated lipid storage. To evaluate systemic cues in mice housed at thermoneutral temperatures, we characterized the circulating lipidome, and show that sera are highly depleted in some HDL-associated phospholipids, specifically phospholipids containing the essential fatty acid, 18:2 linoleic acid, and its derivative, arachidonic acid (20:4) and related ether-phospholipids. Given the role of these fatty acids in inflammatory responses, we propose they may underlie the differences in disease progression observed at thermoneutrality.

Allium macrostemon whole extract ameliorates obesity-induced inflammation and endoplasmic reticulum stress in adipose tissue of high-fat diet-fed C57BL/6N mice

Background

Obesity is a major risk factor for metabolic syndrome and a serious health concern worldwide. Various strategies exist to treat and prevent obesity, including dietary approaches using bioactive ingredients from natural sources.

Objective

This study aimed to investigate the anti-obesity effect of whole-plant Allium macrostemon (also called as long-stamen chive) extract (AME) as a potential new functional food.

Design

C57BL/6N mice were divided into three groups and fed either a control diet (CD), high-fat diet (HFD), or HFD with AME treatment (200 mg/kg BW daily) for 9 weeks. The mice in the CD and HFD groups were treated with vehicle control.

Results

AME supplementation reduced HFD-induced body weight gain, fat mass, and adipocyte size. AME suppressed peroxisome proliferator-activated receptor γ and fatty acid synthase mRNA expression, indicating reduced adipogenesis and lipogenesis in adipose tissue. In addition, AME lowered inflammation in adipose tissue, as demonstrated by the lower number of crown-like structures, mRNA, and/or protein expression of macrophage filtration markers, as well as pro-inflammatory cytokines, including F4/80 and IL-6. Endoplasmic reticulum stress was also alleviated by AME administration in adipose tissue. Several phenolic acids known to have anti-obesity effects, including ellagic acid, protocatechuic acid, and catechin, have been identified in AME.

Conclusion

By suppressing adipose tissue expansion and inflammation, AME is a potential functional food for the prevention and/or treatment of obesity and its complications.

Mild hypercholesterolemia impacts achilles sub-tendon mechanical properties in young rats

BACKGROUND

Hypercholesterolemia is associated with tendon pathology, but the reasons underpinning this relationship are not well understood. Cholesterol can accumulate in the tendon non-collagenous matrix which may affect both global and local tissue mechanics. Changes to the local strain environment within tendon may have significant implications for mechanosensitive tenocytes. Here, we investigated the association between elevated blood cholesterol and presence of tendon lipids in the Achilles tendon. We expected lipids to be localised in the proteoglycan-rich inter-sub-tendon matrix (ISTM), therefore we also sought to examine the impact of this on the biomechanical and viscoelastic properties of the ISTM.

METHODS

The Achilles tendons of 32 young wild-type (SD) and 32 apolipoprotein E knock-out rats (ApoE^-/-) were harvested at 15.6 ± 2.3 weeks of age. 32 specimens underwent histological examination to assess the distribution of lipids throughout sub-tendons and ISTM. The remaining specimens were prepared for biomechanical testing, where the ISTM between the gastrocnemius and soleus sub-tendons was subjected to shear load mechanical testing. A sub-set of tests were video recorded to enable a strain analysis.

RESULTS

ApoE^-/- serum cholesterol was double that of SD rats (mean 2.25 vs. 1.10 mg/ml, p < 0.001) indicating a relatively mild hypercholesterolemia phenotype. Nonetheless, we found histological evidence of esterified lipids in the ISTM and unesterified lipids in the sub-tendons, although the location or intensity of staining was not appreciably different between rat strains. Despite a lack of observable histological differences in lipid content between groups, there were significant differences in the mechanical and viscoelastic behaviour of the Achilles sub-tendon matrix.

CONCLUSION

Even slightly elevated cholesterol may result in subtle changes to tendon biomechanical properties and hence injury risk. The young age of our cohort and the mild phenotype of our ApoE^-/- rats are likely to have limited our findings and so we also conclude that the ApoE^-/- rat model is not well suited for investigating the biomechanical impact of tendon xanthomas on Achilles sub-tendon function.

Interspecies and regional variability of alcohol action on large cerebral arteries: regulation by KCNMB1 proteins

Alcohol intake leading to blood ethanol concentrations (BEC) ≥ legal intoxication modifies brain blood flow with increases in some regions and decreases in others. Brain regions receive blood from the Willis' circle branches: anterior, middle (MCA) and posterior cerebral (PCA), and basilar (BA) arteries. Rats and mice have been used to identify the targets mediating ethanol-induced effects on cerebral arteries, with conclusions being freely interchanged, albeit data were obtained in different species/arterial branches. We tested whether ethanol action on cerebral arteries differed between male rat and mouse and/or across different brain regions and identified the targets of alcohol action. In both species and all Willis' circle branches, ethanol evoked reversible and concentration-dependent constriction (EC50s ≈ 37-86 mM; below lethal BEC in alcohol-naïve humans). Although showing similar constriction to depolarization, both species displayed differential responses to ethanol: in mice, MCA constriction was highly sensitive to the presence/absence of the endothelium, whereas in rat PCA was significantly more sensitive to ethanol than its mouse counterpart. In the rat, but not the mouse, BA was more ethanol sensitive than other branches. Both interspecies and regional variability were ameliorated by endothelium. Selective large conductance (BK) channel block in de-endothelialized vessels demonstrated that these channels were the effectors of alcohol-induced cerebral artery constriction across regions and species. Variabilities in alcohol actions did not fully matched KCNMB1 expression across vessels. However, immunofluorescence data from KCNMB1-/- mouse arteries electroporated with KCNMB1-coding cDNA demonstrate that KCNMB1 proteins, which regulate smooth muscle (SM) BK channel function and vasodilation, regulate interspecies and regional variability of brain artery responses to alcohol.

Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs

In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57-73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.

The impact of mild hypercholesterolemia on injury repair in the rat patellar tendon

Hypercholesterolemia is associated with tendon pathology and injury prevalence. Lipids can accumulate in the tendon's extracellular spaces, which may disrupt its hierarchical structure and the tenocytes physicochemical environment. We hypothesized that the tendon's ability to repair after injury would be attenuated with elevated cholesterol levels, leading to inferior mechanical properties. Fifty wild-type (sSD) and 50 apolipoprotein E knock-out rats (ApoE^{-/ -} ) were given a unilateral patellar tendon (PT) injury at 12 weeks old; the uninjured limb served as a control. Animals were euthanized at 3-, 14,- or 42-days postinjury and PT healing was investigated. ApoE^{-/ -} serum cholesterol was double that of SD rats (mean: 2.12 vs. 0.99 mg/mL, p < 0.001) and cholesterol level was related to the expression of several genes after injury; notably rats with higher cholesterol demonstrated a blunted inflammatory response. There was little physical evidence of tendon lipid content or differences in injury repair between groups, therefore we were not surprised that tendon mechanical or material properties did not differ between strains. The young age and the mild phenotype of our ApoE^{-/ -} rats might explain these findings. Hydroxyproline content was positively related to total blood cholesterol, but this result did not translate to observable biomechanical differences, perhaps due to the narrow range of cholesterol levels observed. Tendon inflammatory and healing activity is modulated at the mRNA level even with a mild hypercholesterolemia. These important initial impacts need to be investigated as they may contribute to the known consequences of cholesterol on tendons in humans.

Insulin-like growth factor 1 reduces coronary atherosclerosis in pigs with familial hypercholesterolemia

Although murine models of coronary atherosclerotic disease have been used extensively to determine mechanisms, limited new therapeutic options have emerged. Pigs with familial hypercholesterolemia (FH pigs) develop complex coronary atheromas that are almost identical to human lesions. We reported previously that insulin-like growth factor 1 (IGF-1) reduced aortic atherosclerosis and promoted features of stable plaque in a murine model. We administered human recombinant IGF-1 or saline (control) in atherosclerotic FH pigs for 6 months. IGF-1 decreased relative coronary atheroma in vivo (intravascular ultrasound) and reduced lesion cross-sectional area (postmortem histology). IGF-1 increased plaque's fibrous cap thickness, and reduced necrotic core, macrophage content, and cell apoptosis, consistent with promotion of a stable plaque phenotype. IGF-1 reduced circulating triglycerides, markers of systemic oxidative stress, and CXCL12 chemokine levels. We used spatial transcriptomics (ST) to identify global transcriptome changes in advanced plaque compartments and to obtain mechanistic insights into IGF-1 effects. ST analysis showed that IGF-1 suppressed FOS/FOSB factors and gene expression of MMP9 and CXCL14 in plaque macrophages, suggesting possible involvement of these molecules in IGF-1's effect on atherosclerosis. Thus, IGF-1 reduced coronary plaque burden and promoted features of stable plaque in a pig model, providing support for consideration of clinical trials.

Effects of extender filtration and egg yolk concentration on canine semen cryopreservation

The semen cooling and freezing extenders commonly contain the chicken egg yolk (EY) as the main sperm cryoprotectant. Besides its advantages, the EY has large lipoprotein granules that cause several physical and biological interferences. The previous studies have proposed several methods to resolve the problems with the EY-based semen extenders, including mechanical agitation, EY fractionation, replacing the EY with purified EY LDL, and ultrasonication. In the current research, we aimed to evaluate the syringe filtration (220 nm) of an EY-based canine semen freezing extender as a simple and cheap method to remove the EY granules. We also studied the possibility of re-aggregation of EY granules after cooling, freeze/thawing, and lyophilization/rehydration of the filtered extenders. Additionally, we compared the effects of the filtration on lipid profile, turbidity, EY particle size distribution, and osmolality of the EY-based extenders. Next, we examined the effects of filtered extenders containing different levels of EY (5%, 10%, 15%, 20%, and 25%) versus the control extender (20% EY, unfiltered) on post-thaw sperm quality traits. We collected the semen samples from seven clinically healthy mixed-breed adult dogs and pooled them for sperm freezing procedures. Samplings were repeated at least five times, independently. Our results indicated that the syringe filtration could remove the large EY particles and reduce the extender turbidity without affecting the lipid profile of the whole extender solution. The filtered extender supplemented with 25% (v/v) EY led to the best post-thaw canine spermatozoa quality markers. The frozen-thawed spermatozoa evaluations included motility parameters (computer-assisted semen analysis system), membrane and acrosome integrity (hypo-osmotic swelling test, chlortetracycline binding assay), DNA fragmentation (sperm chromatin dispersion assay), membrane lipid peroxidation (MDA levels), apoptosis (Annexin V/propidium iodide assay), and fertility-associated sperm mRNA transcript abundance (protamine 2 and 3). In conclusion, the syringe filtration of the EY-based semen extenders was a simple and cheap method that could effectively remove large EY lipoprotein granules and possibly prevent EY-origin bacterial contamination of the final extender solution. The EY at 25% (v/v) concentration in the filtered extenders resulted in the highest canine spermatozoa cryo-tolerance.

Graduate Student Literature Review: A scoping review on the impact of consumption of dairy products on phosphatidylcholine and lysophosphatidylcholine in circulation and the liver in human studies and animal models

Dairy consumption is inversely related to the risk of developing type 2 diabetes in epidemiological research. One proposed hypothesis is that phospholipid (PL) species associated with dairy consumption mediate this relationship. This scoping review aimed to identify the existing literature in animal and human trials investigating the impact of dairy products, including milk, yogurt, and cheese as well as dairy-derived PL supplementation on PL and its species in the circulation, summarizing the characteristics of these studies and identifying research gaps. A systematic search was conducted across 3 databases (PubMed, Scopus, and Web of Science) in March 2021. Of 2,427 identified references, 15 studies (7 humans and 8 animal studies) met the eligibility criteria and were included in the final narrative synthesis. The evidence base was heterogeneous, involving a variety of clinical and preclinical studies, metabolically healthy or obese/diabetic participants or animal models, and displayed mixed findings. Circulating postprandial concentrations of total PL were elevated acutely but unchanged after longer intervention with dairy products. The PL concentration remained stable even after a high dosage of milk supplemented with dairy-derived PL, which may be related to increased fecal excretion; however, certain phosphatidylcholine (PC) or lysophosphatidylcholine species were increased in circulation by interventions. These include several PC species with 32 to 38 total carbons in addition to the dairy biomarkers C15:0 and C17:0. The results of this scoping review demonstrate a small body of literature indicating that dairy products can influence blood concentrations of PC and lysophosphatidylcholine species in both rodents and humans without alteration of total PL and PC. There is a lack of well-designed trials in humans and animals that explore the potential differences between individual dairy foods on PL species. In addition, trials to understand the bioactive properties of PC and lysophosphatidylcholine species on cardiometabolic risk are needed.

Transport Form and Pathway from the Intestine to the Peripheral Tissues and the Intestinal Absorption and Metabolism Properties of Oleamide

This study aimed to obtain information on the transport form and pathway from the intestine to the peripheral tissues and on the intestinal absorption and metabolism properties of oleamide (cis-9-octadecenamide). Oleamide was primarily transported via the portal vein. Density gradient centrifugation indicated that plasma oleamide was enriched in the fractions containing albumin in the portal and peripheral blood. Oleamide formed a complex with albumin in an endothermic reaction (apparent K_d = 4.4 μM). The CD36 inhibitor inhibited the oleamide uptake into the intestinal epithelial Caco-2 cells, and oleamide decreased the cell surface CD36 level. The fatty acid amide hydrolase (FAAH) inhibitor increased the transepithelial transport of oleamide across Caco-2 cells and the plasma oleamide concentration in mice intragastrically administered with oleamide. These results indicate that oleamide is transported primarily via the portal vein as a complex with albumin. Furthermore, we suggest that oleamide is taken up via CD36 in the small intestine and degraded intracellularly by FAAH.

Dietary sinapic acid attenuated high-fat diet-induced lipid metabolism and oxidative stress in male Syrian hamsters

The current study investigated the effects of sinapic acid on high-fat diet (HFD)-induced lipid metabolism and oxidative stress in male Syrian hamsters. Sinapic acid treatment significantly reduced body weight, epididymal fat, and perirenal fat mass in HFD hamsters. Sinapic acid also improved dyslipidemia levels (reducing the serum levels of total cholesterol, triglycerides, and low-density lipoprotein cholesterol, and increasing the high-density lipoprotein cholesterol) and increased T-AOC levels to mitigate oxidative stress injury. Moreover, sinapic acid intervention increased the activations of PPAR-γ, CPT-1, and CYP7A1 and decreased the activations of FAS, ACC1, SREBP1, SREBP2, and HMGCR in the livers of HFD hamsters. In addition, sinapic acid intervention also significantly inhibited the intestinal mRNA levels of Srebp2 and Npc1l1 in HFD hamsters. In conclusion, sinapic acid can significantly attenuate abnormal lipid metabolism in the development of HFD-induced obesity and reduce the level of oxidative stress to exert its anti-obesity effect. PRACTICAL APPLICATIONS: Obesity is the main cause of some chronic metabolic syndromes, such as dyslipidemia, nonalcoholic fatty liver disease, diabetes, and hyperuricemia. Searching for new, safe, and effective natural products in weight loss and fat reduction has become one of the hot research topics. As a natural source of simple phenolic acids, sinapic acid is present in fruits, vegetables, and grains and has been indicated to have anti-inflammatory, antioxidant, antihyperuricemic, lipid homeostasis regulation, and anticancer activities. However, the lipid metabolism- and oxidative stress-regulating activities of sinapic acid are not clear. Here, the current study investigated the lipid metabolism and oxidative stress regulating activities of sinapic acid in male Syrian hamsters fed a high-fat diet.

Lipoprotein interactions with water-soluble NIR-II emitting aza-BODIPYs boost the fluorescence signal and favor selective tumor targeting

Following intravenous administration, the interaction of fluorescent exogenous molecules with circulating endogenous transporters can influence their photophysical properties as well as their fate and distribution, and possibly their recognition by different cell types. This type of interaction can be used to optimize the drug delivery but also the imaging properties of a compound of interest. In this study, we investigated the behavior of SWIR-WAZABY-01 fluorophore, a water-soluble aza-BODIPY dye emitting in the NIR-II region, both in vitro and in vivo. While the fluorescence emission of SWIR-WAZABY-01 was weak in aqueous solutions, it was intensely magnified in plasma (∼ ×30). Further analyses using lipoprotein gel electrophoresis and ultracentrifugation revealed interactions between SWIR-WAZABY-01 and plasma lipoproteins in vitro and ex vivo, in particular with LDL. The tumor uptake mechanism of SWIR-WAZABY-01 was investigated based on the presence of low-density lipoprotein (LDL) receptors and passive tumor uptake. Overall, we found that SWIR-WAZABY-01 interacts with lipoproteins enhancing their NIR-II fluorescence emission, and driving the tumor accumulation with regards to the expression of lipoprotein receptors (LDLR, SR-BI). Moreover, SWIR-WAZABY-01, by exploiting endogenous lipoproteins, arises as a new, potent and relevant tool to efficiently label LDL involved in pathologies.

Identifying cell receptors for the nanoparticle protein corona using genome screens

Nanotechnology provides platforms to deliver medical agents to specific cells. However, the nanoparticle's surface becomes covered with serum proteins in the blood after administration despite engineering efforts to protect it with targeting or blocking molecules. Here, we developed a strategy to identify the main interactions between nanoparticle-adsorbed proteins and a cell by integrating mass spectrometry with pooled genome screens and Search Tool for the Retrieval of Interacting Genes analysis. We found that the low-density lipoprotein (LDL) receptor was responsible for approximately 75% of serum-coated gold nanoparticle uptake in U-87 MG cells. Apolipoprotein B and complement C8 proteins on the nanoparticle mediated uptake through the LDL receptor. In vivo, nanoparticle accumulation correlated with LDL receptor expression in the organs of mice. A detailed understanding of how adsorbed serum proteins bind to cell receptors will lay the groundwork for controlling the delivery of nanoparticles at the molecular level to diseased tissues for therapeutic and diagnostic applications.

Maternal high-cholesterol diet negatively programs offspring bone development and downregulates hedgehog signaling in osteoblasts

Cholesterol is one of the essential intrauterine factors required for fetal growth and development. Maternal high cholesterol levels are known to be detrimental for offspring health. However, its long-term effect on offspring skeletal development remains to be elucidated. We performed our studies in two strains of mice (C57BL6/J and Swiss Albino) and human subjects (65 mother-female newborn dyads) to understand the regulation of offspring skeletal growth by maternal high cholesterol. We found that mice offspring from high-cholesterol-fed dams had low birth weight, smaller body length, and delayed skeletal ossification at the E18.5 embryonic stage. Moreover, we observed that the offspring did not recover from the reduced skeletal mass and exhibited a low bone mass phenotype throughout their life. We attributed this effect to reduced osteoblast cell activity with a concomitant increase in the osteoclast cell population. Our investigation of the molecular mechanism revealed that offspring from high-cholesterol-fed dams had a decrease in the expression of ligands and proteins involved in hedgehog signaling. Further, our cross-sectional study of human subjects showed a significant inverse correlation between maternal blood cholesterol levels and cord blood bone formation markers. Moreover, the bone formation markers were significantly lower in the female newborns of hypercholesterolemic mothers compared with mothers with normal cholesterolemic levels. Together, our results suggest that maternal high cholesterol levels deleteriously program offspring bone mass and bone quality and downregulate the hedgehog signaling pathway in their osteoblasts.

Untargeted lipidomic analysis of plasma from obese women submitted to combined physical exercise

This study aimed to determine the changes of lipidome in obese women undergoing combined physical exercise training. Fourteen adult women with obesity (mean BMI and age, 33 kg/m² and 34 ± 5 years), were submitted to combined physical training (aerobic and strength exercises, alternately, 55 min at 75–90% of the maximum heart rate, 3 times a week) for 8 weeks. All participants were evaluated before and after the training intervention for lipidome, anthropometric measurements, muscle strength, and maximum oxygen consumption (VO₂max). Untargeted liquid chromatography-mass spectrometry analyses allowed the identification of 1252 variables, of which 160 were significant (p < 0.05), and 61 were identified as molecular species of lipids. Volcano plot analysis revealed LPC(16:0p), LPC(18:0p), LPC(20:2), and arachidonic acid upregulated and PC(38:1p), PC(40:4), PC(40:4p) downregulated after combined physical exercise. From the results of the overall Principal component analysis (PCA), the major finding was SM(d18:1/20:0), arachidonic acid, and PC(40:6) species. Other changes included a reduction in waist circumference (Δ = − 2 cm) (p < 0.05), with no weight loss. In conclusion, 8-week of combined exercise training in obese women brought changes in different classes of lipids. This study provides further information to understand the effect of combined physical exercise on lipids related to obesity.

A Divergent Selection on Breast Meat Ultimate pH, a Key Factor for Chicken Meat Quality, is Associated With Different Circulating Lipid Profiles

Background: Chicken meat has become a major source of protein for human consumption. However, the quality of the meat is not yet under control, especially since pH values that are too low or too high are often observed. In an attempt to get a better understanding of the genetic and biochemical determinants of the ultimate pH, two genetic lines of broilers were divergently selected for low (pHu−) or high (pHu+) breast meat pHu. In this study, the serum lipidome of 17-day-old broilers from both lines was screened for pHu markers using liquid-chromatography coupled with mass spectrometry (LC-HRMS).

Results: A total of 185 lipids belonging to 4 groups (glycerolipids, glycerophospholipids, sterols, sphingolipids) were identified in the sera of 268 broilers from the pHu lines by targeted lipidomics. The glycerolipids, which are involved in energy storage, were in higher concentration in the blood of pHu− birds. The glycerophospholipids (phosphatidylcholines, phosphatidylethanolamines) with long and polyunsaturated acyl chains were more abundant in pHu+ than in pHu− while the lysophosphatidylcholines and lysophosphatidylethanolamines, known to be associated with starch, were observed in higher quantity in the serum of the pHu− line. Finally, the concentration of the sterols and the ceramides, belonging to the sphingolipids class, were higher in the pHu+ and pHu−, respectively. Furthermore, orthogonal partial least-squares analyses highlighted a set of 68 lipids explaining 77% of the differences between the two broilers lines (R²Y = 0.77, Q² = 0.67). Among these lipids, a subset of 40 predictors of the pHu value was identified with a Root Mean Squared Error of Estimation of 0.18 pH unit (R²Y = 0.69 and Q² = 0.62). The predictive model of the pHu value was externally validated on 68 birds with a Root Mean Squared Error of Prediction of 0.25 pH unit.

Conclusion: The sets of molecules identified will be useful for a better understanding of relationship between serum lipid profile and meat quality, and will contribute to define easily accessible pHu biomarkers on live birds that could be useful in genetic selection.

Considerations for extracellular vesicle and lipoprotein interactions in cell culture assays

With an exponential increase in extracellular vesicle (EV) studies in the past decade, focus has been placed on standardization of experimental design to ensure inter‐study comparisons and validity of conclusions. In the case of in vitro assays, the composition of cell culture media is important to consider for EV studies. In particular, levels of lipoproteins, which are critical components of the interstitial fluid, should be taken into consideration. Results from this study reveal that lipoprotein levels in cell culture medium impact the effects that EVs have on recipient cells. Additionally, evidence of EV binding and fusion to lipoprotein‐like structures in plasma is provided. However, it is unclear whether the impact of lipoproteins in cell culture is due to direct interactions with EVs, indirect effects, or a combination of both mechanisms. Taken together, cell culture studies performed in the absence of physiological levels of lipoproteins are unlikely to reflect interactions that occur between EVs and recipient cells in an in vivo environment.

Lipid-based strategies used to identify extracellular vesicles in flow cytometry can be confounded by lipoproteins: Evaluations of annexin V, lactadherin, and detergent lysis

Flow cytometry (FCM) is a popular method used in characterisation of extracellular vesicles (EVs). Circulating EVs are often identified by FCM by exploiting the lipid nature of EVs by staining with Annexin V (Anx5) or lactadherin against the membrane phospholipid phosphatidylserine (PS) and evaluating the specificity of the labels by detergent lysis of EVs. Here, we investigate whether PS labelling and detergent lysis approaches are confounded by lipoproteins, another family of lipid-based nanoparticles found in blood, in both frozen and fresh blood plasma. We demonstrated that Anx5 and lactadherin in addition to EVs stained ApoB-containing lipoproteins, identified by the use of fluorophore-labelled polyclonal ApoB-antibody, and that Anx5 had a significantly larger tendency for labelling lipoprotein-bound PS than lactadherin. Furthermore, detergent lysis resulted in a decrease in both EV and lipoprotein events and especially lipoproteins positive for either Anx5 or lactadherin. Taken together, our findings pose concerns to the use of lipid-based strategies in identifying EVs by FCM and support the use of transmembrane proteins such as tetraspannins to distinguish EVs from lipoproteins.

Exercise training worsens cardiac performance in males but does not change ejection fraction and improves hypertrophy in females in a mouse model of metabolic syndrome

BACKGROUND

Metabolic syndrome (MetS) refers to a cluster of co-existing cardio-metabolic risk factors, including visceral obesity, dyslipidemia, hyperglycemia with insulin resistance, and hypertension. As there is a close link between MetS and cardiovascular diseases, we aimed to investigate the sex-based differences in MetS-associated heart failure (HF) and cardiovascular response to regular exercise training (ET).

METHODS

High-fat diet-fed male and female APOB-100 transgenic (HFD/APOB-100, 3 months) mice were used as MetS models, and age- and sex-matched C57BL/6 wild-type mice on standard diet served as healthy controls (SD/WT). Both the SD/WT and HFD/APOB-100 mice were divided into sedentary and ET groups, the latter running on a treadmill (0.9 km/h) for 45 min 5 times per week for 7 months. At month 9, transthoracic echocardiography was performed to monitor cardiac function and morphology. At the termination of the experiment at month 10, blood was collected for serum low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol measurements and homeostatic assessment model for insulin resistance (HOMA-IR) calculation. Cardiomyocyte hypertrophy and fibrosis were assessed by histology. Left ventricular expressions of selected genes associated with metabolism, inflammation, and stress response were investigated by qPCR.

RESULTS

Both HFD/APOB-100 males and females developed obesity and hypercholesterolemia; however, only males showed insulin resistance. ET did not change these metabolic parameters. HFD/APOB-100 males showed echocardiographic signs of mild HF with dilated ventricles and thinner walls, whereas females presented the beginning of left ventricular hypertrophy. In response to ET, SD/WT males developed increased left ventricular volumes, whereas females responded with physiologic hypertrophy. Exercise-trained HFD/APOB-100 males presented worsening HF with reduced ejection fraction; however, ET did not change the ejection fraction and reversed the echocardiographic signs of left ventricular hypertrophy in HFD/APOB-100 females. The left ventricular expression of the leptin receptor was higher in females than males in the SD/WT groups. Left ventricular expression levels of stress response-related genes were higher in the exercise-trained HFD/APOB-100 males and exercise-trained SD/WT females than exercise-trained SD/WT males.

CONCLUSIONS

HFD/APOB-100 mice showed sex-specific cardiovascular responses to MetS and ET; however, left ventricular gene expressions were similar between the groups except for leptin receptor and several stress response-related genes.

Research-Relevant Clinical Pathology Resources: Emphasis on Mice, Rats, Rabbits, Dogs, Minipigs, and Non-Human Primates

Clinical pathology testing for investigative or biomedical research and for preclinical toxicity and safety assessment in laboratory animals is a distinct specialty requiring an understanding of species specific and other influential variables on results and interpretation. This review of clinical pathology principles and testing recommendations in laboratory animal species aims to provide a useful resource for researchers, veterinary specialists, toxicologists, and clinical or anatomic pathologists.

Acoustofluidic dynamic interfacial tensiometry

The interfacial tension (IFT) of fluids plays an essential role in industrial, biomedical, and synthetic chemistry applications; however, measuring IFT at ultralow volumes is challenging. Here, we report a novel method for sessile drop tensiometry using surface acoustic waves (SAWs). The IFT of the fluids was determined by acquiring the silhouette of an axisymmetric sessile drop and applying iterative fitting using Taylor's deformation equation. Owing to physiochemical differences, upon interacting with acoustic waves, each microfluid has a different streaming velocity. This streaming velocity dictates any subsequent changes in droplet shape (i.e., height and width). We demonstrate the effectiveness of the proposed SAW-based tensiometry technique using blood plasma to screen for high leptin levels. The proposed device can measure the IFT of microscale liquid volumes (up to 1 μL) with an error margin of only ±5% (at 25 °C), which deviates from previous reported results. As such, this method provides pathologists with a solution for the pre-diagnosis of various blood-related diseases.

Heukcha, naturally post-fermented green tea extract, ameliorates diet-induced hypercholesterolemia and NAFLD in hamster

Hypercholesterolemia, characterized by an increase in plasma low-density lipoprotein (LDL) cholesterol and total cholesterol (TC), is the leading cause of non-alcoholic fatty liver disease (NAFLD). The present study examined the effect of Heukcha extract (HCE), a naturally post-fermented green tea extract, on diet-induced hypercholesterolemia and related NAFLD in hamsters that metabolize lipids in a similar fashion to humans. The 10-week-old golden Syrian hamsters were fed a normal diet (ND) or a high cholesterol diet (HCD) containing 0.2% cholesterol and 10% lard, and some were also given HCE (200 or 500 mg/kg/day) orally for 12 weeks. The HCE did not affect the body weight gain, food intake, or the calorie intake. HCD significantly (p < 0.05) increased LDL (0.9 to 2.1 mmol/L), TC (2.7 to 7.8 mmol/L), and triglyceride (TG; 2.3 to 4.0 mmol/L), which was significantly decreased by 27.7%, 17.3%, and 60%, respectively, by HCE. HDL was significantly increased by HCD (0.6 to 1.6 mmol/L), but it was not affected by HCE administration. Furthermore, HCE suppressed HCD-induced liver oxidative stress, fibrosis, and lipid accumulation almost to control levels. Interestingly, HCE significantly increased the protein level of cholesterol 7 alpha-hydroxylase (CYP7A1), the rate-limiting enzyme for bile acid synthesis, by 1.5-fold in the liver. The present data suggest that HCE could be a functional food ingredient that can suppress the occurrence of diet-induced hypercholesterolemia and NAFLD, possibly by increasing the expression of CYP7A1.

Inhibition of Extracellular Cathepsin D Reduces Hepatic Lipid Accumulation and Leads to Mild Changes in Inflammationin NASH Mice

Background & Aims

The lysosomal enzyme, cathepsin D (CTSD) has been implicated in the pathogenesis of non-alcoholic steatohepatitis (NASH), a disease characterised by hepatic steatosis and inflammation. We have previously demonstrated that specific inhibition of the extracellular CTSD leads to improved metabolic features in Sprague-Dawley rats with steatosis. However, the individual roles of extracellular and intracellular CTSD in NASH are not yet known. In the current study, we evaluated the underlying mechanisms of extracellular and intracellular CTSD fractions in NASH-related metabolic inflammation using specific small-molecule inhibitors.

Methods

Low-density lipoprotein receptor knock out (Ldlr-/-) mice were fed a high-fat, high cholesterol (HFC) diet for ten weeks to induce NASH. Further, to investigate the effects of CTSD inhibition, mice were injected either with an intracellular (GA-12) or extracellular (CTD-002) CTSD inhibitor or vehicle control at doses of 50 mg/kg body weight subcutaneously once in two days for ten weeks.

Results

Ldlr-/- mice treated with extracellular CTSD inhibitor showed reduced hepatic lipid accumulation and an associated increase in faecal bile acid levels as compared to intracellular CTSD inhibitor-treated mice. Furthermore, in contrast to intracellular CTSD inhibition, extracellular CTSD inhibition switched the systemic immune status of the mice to an anti-inflammatory profile. In line, label-free mass spectrometry-based proteomics revealed that extra- and intracellular CTSD fractions modulate proteins belonging to distinct metabolic pathways.

Conclusion

We have provided clinically translatable evidence that extracellular CTSD inhibition shows some beneficial metabolic and systemic inflammatory effects which are distinct from intracellular CTSD inhibition. Considering that intracellular CTSD inhibition is involved in essential physiological processes, specific inhibitors capable of blocking extracellular CTSD activity, can be promising and safe NASH drugs.

Changes in Key Mitochondrial Lipids Accompany Mitochondrial Dysfunction and Oxidative Stress in NAFLD

Nonalcoholic fatty liver disease (NAFLD) is a dysmetabolic hepatic damage of increasing severity: simple fat accumulation (steatosis), nonalcoholic steatohepatitis (NASH), and hepatic fibrosis. Oxidative stress is considered an important factor in producing hepatocyte injury associated with NAFLD progression. Studies also suggest a link between the accumulation of specific hepatic lipid species, mitochondrial dysfunction, and the progression of NAFLD. However, it is unclear whether mitochondrial lipid modifications are involved in NAFLD progression. To gain insight into the relationship between mitochondrial lipids and disease progression through different stages of NAFLD, we performed lipidomic analyses on mouse livers at different stages of western diet-induced NAFLD, with or without hepatic fibrosis. After organelle separation, we studied separately the mitochondrial and the “nonmitochondrial” hepatic lipidomes. We identified 719 lipid species from 16 lipid families. Remarkably, the western diet triggered time-dependent changes in the mitochondrial lipidome, whereas the “nonmitochondrial” lipidome showed little difference with levels of hepatic steatosis or the presence of fibrosis. In mitochondria, the changes in the lipidome preceded hepatic fibrosis. In particular, two critical phospholipids, phosphatidic acid (PA) and cardiolipin (CL), displayed opposite responses in mitochondria. Decrease in CL and increase in PA were concurrent with an increase of coenzyme Q. Electron paramagnetic resonance spectroscopy superoxide spin trapping and Cu²⁺ measurement showed the progressive increase in oxidative stress in the liver. Overall, these results suggest mitochondrial lipid modifications could act as an early event in mitochondrial dysfunction and NAFLD progression.

Plasma lipidomic analysis shows a disease progression signature in mdx mice

Duchenne muscular dystrophy (DMD) is a rare genetic disorder affecting paediatric patients. The disease course is characterized by loss of muscle mass, which is rapidly substituted by fibrotic and adipose tissue. Clinical and preclinical models have clarified the processes leading to muscle damage and myofiber degeneration. Analysis of the fat component is however emerging as more evidence shows how muscle fat fraction is associated with patient performance and prognosis. In this article we aimed to study whether alterations exist in the composition of lipids in plasma samples obtained from mouse models. Analysis of plasma samples was performed in 4 mouse models of DMD and wild-type mice by LC–MS. Longitudinal samplings of individual mice covering an observational period of 7 months were obtained to cover the different phases of the disease. We report clear elevation of glycerolipids and glycerophospholipids families in dystrophic mice compared to healthy mice. Triacylglycerols were the strongest contributors to the signatures in mice. Annotation of individual lipids confirmed the elevation of lipids belonging to these families as strongest discriminants between healthy and dystrophic mice. A few sphingolipids (such as ganglioside GM2, sphingomyelin and ceramide), sterol lipids (such as cholesteryl oleate and cholesteryl arachidonate) and a fatty acyl (stearic acid) were also found to be affected in dystrophic mice. Analysis of serum and plasma samples show how several lipids are affected in dystrophic mice affected by muscular dystrophy. This study sets the basis to further investigations to understand how the lipid signature relates to the disease biology and muscle performance.

Apolipoprotein C3 aggravates diabetic nephropathy in type 1 diabetes by activating the renal TLR2/NF-κB pathway

OBJECTIVE

Apolipoprotein C3 (ApoC3) is a regulator of triglyceride metabolism and inflammation, and its plasma levels are positively correlated with the progression of diabetic nephropathy (DN) in patients. However, the role and underlying mechanism of ApoC3 in DN remain unclear.

METHODS

Diabetes was induced in ApoC3 transgenic (Tg) and knockout (KO) mice by injection of streptozotocin. We studied the effect of ApoC3 on type 1 DN after 4 months of diabetes. Plasma glucose and lipid levels, renal function parameters and inflammation- and fibrogenesis-related gene and protein expression levels were studied. In vitro, human mesangial cells (HMCs) were incubated with high levels of glucose or/and triglyceride-rich lipoproteins (TRLs) with a high or low ApoC3 content isolated from Tg or wild-type (WT) mice, respectively, to explore the mechanisms of ApoC3 on development of DN.

RESULTS

We found that compared to WT mice, Tg mice exhibited hypertriglyceridemia (HTG), aggravated early renal function injury and inflammation, enlarged glomerular and mesangial surface areas, renal lipid deposition and elevated fibrogenesis-related gene expression levels after 4 months of diabetes. ApoC3 overexpression activated the renal Toll-like receptor 2 (TLR2) and nuclear factor-κB (NF-κB) signaling pathways and increased the renal gene and protein expression levels of the downstream inflammatory factors TNF-α, VCAM-1 and MCP-1. Unfortunately, we did not find that ApoC3 deficiency had an obvious protective effect against DN. In vitro, we found that TRLs with a high ApoC3 content increased the gene and protein expression levels of inflammation- and fibrogenesis-related factors in HMCs compared to those following administration of the same concentration of TRLs with a low ApoC3 content. These effects of ApoC3 were inhibited by blockade of TLR2 or NF-κB.

CONCLUSIONS

These findings suggest that ApoC3 aggravates early-stage DN by activating the renal TLR2/NF-κB pathway which is partially independent of HTG.

Systemic PFOS and PFOA exposure and disturbed lipid homeostasis in humans: what do we know and what not?

Associations between per- and polyfluoroalkyl substances (PFASs) and increased blood lipids have been repeatedly observed in humans, but a causal relation has been debated. Rodent studies show reverse effects, i.e. decreased blood cholesterol and triglycerides, occurring however at PFAS serum levels at least 100-fold higher than those in humans. This paper aims to present the main issues regarding the modulation of lipid homeostasis by the two most common PFASs, PFOS and PFOA, with emphasis on the underlying mechanisms relevant for humans. Overall, the apparent contrast between human and animal data may be an artifact of dose, with different molecular pathways coming into play upon exposure to PFASs at very low versus high levels. Altogether, the interpretation of existing rodent data on PFOS/PFOA-induced lipid perturbations with respect to the human situation is complex. From a mechanistic perspective, research on human liver cells shows that PFOS/PFOA activate the PPARα pathway, whereas studies on the involvement of other nuclear receptors, like PXR, are less conclusive. Other data indicate that suppression of the nuclear receptor HNF4α signaling pathway, as well as perturbations of bile acid metabolism and transport might be important cellular events that require further investigation. Future studies with human-relevant test systems would help to obtain more insight into the mechanistic pathways pertinent for humans. These studies shall be designed with a careful consideration of appropriate dosing and toxicokinetics, so as to enable biologically plausible quantitative extrapolations. Such research will increase the understanding of possible perturbed lipid homeostasis related to PFOS/ PFOA exposure and the potential implications for human health.

The plasma lipidome of the Quaker parrot (Myiopsitta monachus)

Dyslipidemias and lipid-accumulation disorders are common in captive parrots, in particular in Quaker parrots. Currently available diagnostic tests only measure a fraction of blood lipids and have overall problematic cross-species applicability. Comprehensively analyzing lipids in the plasma of parrots is the first step to better understand their lipid metabolism in health and disease, as well as to explore new lipid biomarkers. The plasma lipidome of 12 Quaker parrots was investigated using UHPLC-MS/MS with both targeted and untargeted methods. Targeted methods on 6 replicates measured 432 lipids comprised of sterol, cholesterol ester, bile acid, fatty acid, acylcarnitine, glycerolipid, glycerophospholipid, and sphingolipid panels. For untargeted lipidomics, precursor ion mass-to-charge ratios were matched to corresponding lipids using the LIPIDMAPS structure database and LipidBlast at the sum composition or acyl species level of information. Sterol lipids and glycerophospholipids constituted the majority of plasma lipids on a molar basis. The most common lipids detected with the targeted methods included free cholesterol, CE(18:2), CE(20:4) for sterol lipids; PC(36:2), PC(34:2), PC(34:1) for glycerophospholipids; TG(52:3), TG(54:4), TG(54:5), TG(52:2) for glycerolipids; SM(d18:1/16:0) for sphingolipids; and palmitic acid for fatty acyls. Over a thousand different lipid species were detected by untargeted lipidomics. Sex differences in the plasma lipidome were observed using heatmaps, principal component analysis, and discriminant analysis. This report presents the first comprehensive database of plasma lipid species in psittacine birds and paves the way for further research into blood lipid diagnostics and the impact of diet, diseases, and drugs on the parrot plasma lipidome.

Mouse models of atherosclerosis and their suitability for the study of myocardial infarction

Atherosclerotic plaques impair vascular function and can lead to arterial obstruction and tissue ischaemia. Rupture of an atherosclerotic plaque within a coronary artery can result in an acute myocardial infarction, which is responsible for significant morbidity and mortality worldwide. Prompt reperfusion can salvage some of the ischaemic territory, but ischaemia and reperfusion (IR) still causes substantial injury and is, therefore, a therapeutic target for further infarct limitation. Numerous cardioprotective strategies have been identified that can limit IR injury in animal models, but none have yet been translated effectively to patients. This disconnect prompts an urgent re-examination of the experimental models used to study IR. Since coronary atherosclerosis is the most prevalent morbidity in this patient population, and impairs coronary vessel function, it is potentially a major confounder in cardioprotective studies. Surprisingly, most studies suggest that atherosclerosis does not have a major impact on cardioprotection in mouse models. However, a major limitation of atherosclerotic animal models is that the plaques usually manifest in the aorta and proximal great vessels, and rarely in the coronary vessels. In this review, we examine the commonly used mouse models of atherosclerosis and their effect on coronary artery function and infarct size. We conclude that none of the commonly used strains of mice are ideal for this purpose; however, more recently developed mouse models of atherosclerosis fulfil the requirement for coronary artery lesions, plaque rupture and lipoprotein patterns resembling the human profile, and may enable the identification of therapeutic interventions more applicable in the clinical setting.

Inclusion of endophenotypes in a standard GWAS facilitate a detailed mechanistic understanding of genetic elements that control blood lipid levels

Dyslipidemia is the primary cause of cardiovascular disease, which is a serious human health problem in large parts of the world. Therefore, it is important to understand the genetic and molecular mechanisms that regulate blood levels of cholesterol and other lipids. Discovery of genetic elements in the regulatory machinery is often based on genome wide associations studies (GWAS) focused on end-point phenotypes such as total cholesterol level or a disease diagnosis. In the present study, we add endophenotypes, such as serum levels of intermediate metabolites in the cholesterol synthesis pathways, to a GWAS analysis and use the pig as an animal model. We do this to increase statistical power and to facilitate biological interpretation of results. Although the study population was limited to ~ 300 individuals, we identify two genome-wide significant associations and ten suggestive associations. Furthermore, we identify 28 tentative associations to loci previously associated with blood lipids or dyslipidemia associated diseases. The associations with endophenotypes may inspire future studies that can dissect the biological mechanisms underlying these previously identified associations and add a new level of understanding to previously identified associations.

Chemerin enhances the adhesion and migration of human endothelial progenitor cells and increases lipid accumulation in mice with atherosclerosis

Background

The role of adipokines in the development of atherosclerosis (AS) has received increasing attention in recent years. This study aimed to explore the effects of chemerin on the functions of human endothelial progenitor cells (EPCs) and to investigate its role in lipid accumulation in ApoE-knockout (ApoE−/−) mice.

Methods

EPCs were cultured and treated with chemerin together with the specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB 203580 in a time- and dose-dependent manner. Changes in migration, adhesion, proliferation and the apoptosis rate of EPCs were detected. ApoE−/− mice with high-fat diet-induced AS were treated with chemerin with or without SB 203580. Weights were recorded, lipid indicators were detected, and tissues sections were stained.

Results

The data showed that chemerin enhanced the adhesion and migration abilities of EPCs, and reduced the apoptosis ratio and that this effect might be mediated through the p38 MAPK pathway. Additionally, chemerin increased the instability of plaques. Compared with the control group and the inhibitor group, ApoE−/− mice treated with chemerin protein had more serious arterial stenosis, higher lipid contents in plaques and decreased collagen. Lipid accumulation in the liver and kidney and inflammation in the hepatic portal area were enhanced by treatment with chemerin, and the size of adipocytes also increased after chemerin treatment. In conclusion, chemerin can enhance the adhesion and migration abilities of human EPCs and reduce the apoptosis ratio. In animals, chemerin can increase lipid accumulation in atherosclerotic plaques and exacerbate plaques instability. At the same time, chemerin can cause abnormal lipid accumulation in the livers and kidneys of model animals. After specifically blocking the p38 MAPK pathway, the effect of chemerin was reduced.

Conclusions

In conclusion, this study showed that chemerin enhances the adhesion and migration abilities of EPCs and increases the instability of plaques and abnormal lipid accumulation in ApoE−/− mice. Furthermore, these effects might be mediated through the p38 MAPK pathway.

Age-related and atherosclerosis-related erythropathy in ApoE/LDLR-/- mice

In this work we applied a multimodal approach to define the age- and atherosclerosis-related biochemical and functional alterations in red blood cells (RBCs) in ApoE/LDLR^-/- mice. Our results revealed that age-related changes in RBCs, such as decreases in RBC deformability and mean height, were more pronounced in ApoE/LDLR^-/- mice than in age-matched control mice (C57BL/6J). The decreases in phospholipid content and level of lipid unsaturation were accompanied by an increase in cholesterol esters and esterified lipids in RBC membranes in aged C57BL/6J mice. The age-related decrease in the phospholipid content was more pronounced in ApoE/LDLR^-/- mice. In contrast, the increase in the total lipid content in RBC membranes occurred only in ApoE/LDLR^-/- mice with advanced atherosclerosis. The age-related alterations also included a decrease in the ratio of turns to α-helices in the secondary structure of hemoglobin (Hb) inside intact RBCs. On the other hand, an increase in the ratio of unordered conformations to α-helices of Hb was observed only in ApoE/LDLR^-/- mice and occurred already at the age of 5-weeks. This was related to hypercholesterolemia and resulted in an increased oxygen-carrying capacity. In conclusion, progressive mechanical and functional alterations of RBCs in aged ApoE/LDLR^-/- mice were more pronounced than in age-matched C57BL/6J mice. Although, several biochemical changes in RBCs in aged ApoE/LDLR^-/- mice recapitulated age-dependent changes observed in control mice, some biochemical features of RBC membranes attributed to hypercholesterolemia were distinct and could contribute to the accelerated deterioration of RBC function in ApoE/LDLR^-/- mice.

Direct differentiation of whole blood for forensic serology analysis by thread spray mass spectrometry

Direct analysis of whole blood on bloodstained textiles is achieved with thread spray mass spectrometry (MS). This capability satisfies investigators' first priority in crime scene investigations, which is determining if a stain is blood. This thread spray method explores the use of evidentiary fabric threads for rapid determination of hemoglobin directly from whole blood within textiles without prior extraction steps. The multiplicity of information that can be derived from the thread spray MS method distinguishes it from the current presumptive Bluestar® method, by enabling the detection of hemoglobin (both α- and β-chains), the heme co-factor and lipids all from a single blood sample. Lipid composition was found to differ for blood samples originating from human, canine, and horse species. The robustness of the thread spray MS method as a forensic analytical platform was evaluated in three ways: (1) its successful applicability to samples previously tested by the Bluestar® presumptive method, offering a confirmatory test without prior sample pre-treatment, (2) successful detection of heme from previously washed fabrics, which demonstrated the unprecedented sensitivity of the thread spray method, and (3) the ability to analyze samples stored under ambient conditions for up to 30 days. These results attest to the potential capabilities of the thread spray MS platform in forensic serology, and its application for direct analysis of evidentiary garments, which confer the advantages of rapid analysis and the reduction of the false positive and negative identification rates for blood on textiles.

Small rodent models of atherosclerosis

The ease of breeding, low cost of maintenance, and relatively short period for developing atherosclerosis make rodents ideal for atherosclerosis research. However, none of the current models accurately model human lipoprotein profile or atherosclerosis progression since each has its advantages and disadvantages. The advent of transgenic technologies much supports animal models' establishment. Notably, two classic transgenic mouse models, apoE-/- and Ldlr-/-, constitute the primary platforms for studying underlying mechanisms and development of pharmaceutical approaches. However, there exist crucial differences between mice and humans, such as the unhumanized lipoprotein profile, and the different plaque progression and characteristics. Among rodents, hamsters and guinea pigs might be the more realistic models in atherosclerosis research based on the similarities in lipoprotein metabolism to humans. Studies involving rat models, a rodent with natural resistance to atherosclerosis, have revealed evidence of atherosclerotic plaques under dietary induction and genetic manipulation by novel technologies, notably CRISPR-Cas9. Ldlr-/- hamster models were established in recent years with severe hyperlipidemia and atherosclerotic lesion formation, which could offer an alternative to classic transgenic mouse models. In this review, we provide an overview of classic and innovative small rodent models in atherosclerosis researches, including mice, rats, hamsters, and guinea pigs, focusing on their lipoprotein metabolism and histopathological changes.

Porcine models for studying complications and organ crosstalk in diabetes mellitus

The worldwide prevalence of diabetes mellitus and obesity is rapidly increasing not only in adults but also in children and adolescents. Diabetes is associated with macrovascular complications increasing the risk for cardiovascular disease and stroke, as well as microvascular complications leading to diabetic nephropathy, retinopathy and neuropathy. Animal models are essential for studying disease mechanisms and for developing and testing diagnostic procedures and therapeutic strategies. Rodent models are most widely used but have limitations in translational research. Porcine models have the potential to bridge the gap between basic studies and clinical trials in human patients. This article provides an overview of concepts for the development of porcine models for diabetes and obesity research, with a focus on genetically engineered models. Diabetes-associated ocular, cardiovascular and renal alterations observed in diabetic pig models are summarized and their similarities with complications in diabetic patients are discussed. Systematic multi-organ biobanking of porcine models of diabetes and obesity and molecular profiling of representative tissue samples on different levels, e.g., on the transcriptome, proteome, or metabolome level, is proposed as a strategy for discovering tissue-specific pathomechanisms and their molecular key drivers using systems biology tools. This is exemplified by a recent study providing multi-omics insights into functional changes of the liver in a transgenic pig model for insulin-deficient diabetes mellitus. Collectively, these approaches will provide a better understanding of organ crosstalk in diabetes mellitus and eventually reveal new molecular targets for the prevention, early diagnosis and treatment of diabetes mellitus and its associated complications.