Lipidology, Volume 2, Issue 1 (March 2025) – 6 articles

Background: Genetic selection and improved nutrition and management practices have transformed the Holstein cow. Objectives: This study examined the impacts of 50 years of selection on milk composition during early lactation by comparing milk from contemporary Holsteins (CH) and a unique population of unselected Holsteins (UH) that produce less than half as much milk as their CH herdmates. Methods: Multiparous UH and CH cows (n = 12/genotype) were housed in the same facility, fed the same diets and subjected to the same management procedures. Milk samples were collected weekly through to week 9 of lactation. The proximate composition of milk was determined by infrared spectroscopy and its lipidome by liquid chromatography–mass spectrometry and structural analysis. Data were analyzed as repeated measures using mixed-model procedures with the week of lactation as the repeated effect. Results: An energy balance nadir occurred at week 1 for UH and CH cows but was more severe (−4.5 vs. −14.8 Mcal net energy per day, respectively) for the CH cows. Lipidomic comparison of the 50 most abundant triacylglycerols (TAGs) revealed that CH milk had more TAGs with at least two preformed fatty acids and fewer TAGs with at least two de novo synthesized fatty acids than UH milk. Fatty acid analysis revealed that the increase in preformed fatty acids in CH cows was responsible for the different TAG profiles in UH and CH milk. Furthermore, CH milk contained less free carnitine, short-chain acylcarnitines and lactic acid but more butyric and 3-hydroxybutyric acid than UH milk in early lactation. Conclusions: These results demonstrate that differences in energy balance were primarily responsible for the differences in milk composition between the UH and CH genotypes in early lactation. Full article

Background/Objectives: Gonad histological analysis (GHA) is the traditional method for assessing the gonad maturation status of blue mussels (Mytilus edulis). GHA has some operational disadvantages, such as limited processing outputs, subjectivity in the assessment of transitional stages of gonadal maturation and the need for experienced and trained operators. Lipids could become important indicators of gonadal maturation as they cover many essential functions during such processes in mussels. In this work, blue mussel ovary (BMO) ultrastructure is integrated with liquid chromatography coupled with mass spectrometry (LC-MS) lipidomics fingerprinting to identify suitable markers for ovarian maturation through the application of chemometrics and machine learning approaches. Methods: BMOs are classified here as ripe or non-ripe by means of GHA and the gamete volume fraction (GVF). Receiving operating characteristic (ROC) curves were used to classify the results of the different statistics according to their area under the curve (AUC), and the functional role of important lipids was assessed by lipid ontology enrichment (LiOn) analysis. Results: This approach allowed for the selection of a panel of 35 lipid molecules (AUC > 0.8) that can distinguish non-ripe from ripe BMOs. Ceramide phosphoethanolamine (CerPE) 40:2 was the molecule with the highest classification ability (AUC 0.905), whereas glycerophosphoserine (PS) was the class mostly changing between the two groups. LiOn analysis indicated significant differences in the functional roles of these lipids, highlighting enrichment terms associated with membrane lipids, lysosomes and highly unsaturated triglycerides (TGs) in non-ripe ovaries, whereas terms associated with storage lipids and low-saturated TG characterised ripe BMOs. Full article

Heterozygous familial hypercholesterolaemia is one of the most common genetic conditions leading to premature atherosclerotic cardiovascular disease. It can be diagnosed using a combination of clinical, biochemical, and genetic tools. Most guidelines recommend screening during childhood and treatment from the age of 8–10 years. However, screening remains sporadic in most countries and the majority of individuals remain undiagnosed. Registry studies have highlighted the ongoing delayed and low percentage of detection of FH in children. Universal early childhood screening models utilising a combination of biomarker-based and genetic testing have been trialled and are in practice in some countries. Newborn screening is a public health success story and one of the most effective public health measures. It offers universal screening for conditions that can result in significant morbidity or even death if left untreated. There has been renewed interest in including familial hypercholesterolaemia in newborn screening programmes. Using cord blood to identify familial hypercholesterolaemia has not yielded convincing results. However, novel screening approaches on dried blood spots that include biomarker-based lipid profile testing alone, in combination with confirmatory genetic testing, or first-line genetic testing have shown promising results. This provides the opportunity of early diagnosis and treatment of infants and their extended families. However, challenges are associated with the inclusion of familial hypercholesterolaemia in newborn screening programmes with significant impacts on the newborn, family members, and public health. Full article

In this review paper, we will evaluate LRP4, a low-density lipoprotein receptor-related protein, and its many roles involving myasthenia gravis (MG), Wnt signaling, bone formation and craniofacial development. In MG, LRP4 is critical to the formation of the neuromuscular junction (NMJ) and the key function is to allow for controlled muscle contraction. LRP4 works in combination with agrin and MuSK to form the functional complex. In Wnt signaling, LRP4 was recently identified as a critical player in the pathway for both bone and tooth development and function. Its ability to act as an inhibitor sheds new light on bone formation and resorption. LRP4 binds sclerostin to LRP5 and LRP6, facilitating inhibitory effects important for bone homeostasis and remodeling. In this review paper, we will summarize the known roles of LRP4 as well as explore future directions for research surrounding LRP4 functionality. Full article

Background/Objectives: Firefighters have an elevated risk of developing cardiovascular disease (CVD). Thus, it is vital to determine areas of health associated with the development of CVD that need improvement in the firefighter population, such as circulating lipids and arterial stiffness. The purpose of this study was to assess the potential relationship of lipid and lipoprotein metrics with measures of arterial stiffness in full-time firefighters in the southeastern United States. Methods: Twenty male full-time firefighters underwent a fasted blood draw to assess circulating lipids. Resting arterial stiffness was then assessed via pulse wave velocity (PWV) using an aortic measure. To determine the linear relationships between arterial stiffness and lipid measures of interest, a series of bivariate correlations were conducted as appropriate. The outcome variable was PWV measured continuously in m/s. The predictor variables were total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), small dense LDL-C (sdLDL-C), and triglycerides (TG) measured in mg/dL. All analyses were carried out using SPSS version 29 (α = 0.05). Results: TG levels were positively and moderately correlated with PWV (r_s = 0.497, p = 0.026). No other significant relationships were detected between PWV and the remaining variables TC (r_s = 0.104, p = 0.664), HDL-C (r_s = −0.328, p = 0.158), LDL-C (r_s = 0.184, p = 0.436), or sdLDL-C (r_s = 0.330, p = 0.155). Conclusion: Higher TG levels are associated with higher PWV and thus, arterial stiffness. Management of circulating TG may be an important consideration in maximizing arterial health and minimizing CVD risk. Full article

Background/Objectives: Metabolic diseases in humans, such as obesity or type 2 diabetes, arise from defects in the body’s ability to take in and store nutrients such as carbohydrates and triglycerides. Previous studies in the fruit fly, Drosophila melanogaster, have identified SR proteins, mRNA splicing factors that regulate splice-site selection, as regulating lipid storage in the fly fat body. However, whether SR proteins function in other tissues to regulate nutrient metabolism is not known. Methods: We focused on studying the role of SR proteins in intestines by decreasing their levels in the fly gut and measuring the concentrations of lipids and glycogen. Results: We further characterized the intestinal functions of 9G8, an SR protein, which displayed an increase in organismal lipid levels when knocked down in the intestine but had less triglyceride storage in isolated intestines. Interestingly, decreasing 9G8 in the intestine resulted in increased intestinal expression of five fatty acid synthesis/elongation enzyme genes, as well as four triglyceride lipase genes, which may contribute to the triglyceride phenotypes we observed in 9G8-RNAi flies. Conclusions: These data suggest that 9G8 regulates whole body and intestinal lipid homeostasis by altering the expression of lipid metabolic enzyme genes in the fly intestine. Full article