Every year around 800 000 people commit suicide, this represents one death every 40 seconds. In the search for possible biological biomarkers associated with suicide and/or psychiatric disorders, serum cholesterol levels have been extensively explored. Several studies have indicated that cholesterol and associated proteins, especially apolipoproteins (Apos), may play an important role in the diagnosis, prognosis, and susceptibility of suicide. Here, we describe the current knowledge and findings in the relationship between apolipoproteins and suicide.

Familial dysbetalipoproteinemia (FD) is a highly atherogenic genetically-based lipid disorder with the underestimated actual prevalence. In the recent years, several biochemical algorithms have been developed to diagnose FD using available laboratory tests. However, there is not enough data on their use in real-world clinical implementation. We studied the applicability of the most accessible biochemical algorithms to diagnose FD in clinical practice. We also investi-gated the prevalence of FD in one of the European regions of Russia based on a population sample. In this study there was detected a high prevalence of FD: 1 in 151. We demonstrated that the diagnostic algorithms of FD including a diagnostic apoB levels require correction, taking into account the characteristics of the distribution of apoB levels in the population. At the same time a triglycerides cutoff ≥1.5 mmol/L may be a useful tool in identifying subjects with FD. We also analyzed the presence and pathogenicity of APOE variants associated with the autosomal dominant FD in a large research sample.

The circadian clock is a 24-hour cycle within the body that regulates various factors, including sleep, body temperature, and hormone secretion. It allows the body to adjust to the light and dark cycle. Disruptions to the circadian rhythm are important risk factors for many diseases, including neurodegenerative illnesses. The central clock is controlled by the clock genes in the suprachiasmatic nucleus (SCN) of the brain, and one of the main functions of the circadian clock is to regulate lipid metabolism. There has been a lack of investigation on the circadian regulation of lipid metabolism-related apolipoprotein genes in the brain; thus, this study sought to summarize the rhythmic expression of clock genes and lipid metabolism-related apolipoprotein genes within the SCN of Mus musculus. Out of the 20 apolipoprotein genes that were studied by the published database, all 9 genes were highly expressed in the SCN. Most of the 6 genes showed rhythmic expression in the brain of mice, suggesting that the master clock might regulate them. The results, therefore, reveal a potential target for preventing and treating circadian disorders. We summarized most studies of lipid-related apolipoprotein genes within limited locations of the SCN and brain to further understand how disordered cerebral lipid metabolism causes multiple brain diseases and disorders. We reviewed recent studies, determined the unexplored questions, and identified a potential direction for further research.

Cardiovascular disease (CVD) places a heavy burden on older patients and the global healthcare system. A large body of evidence suggests that exercise training is essential in preventing and treating cardiovascular disease, but the underlying mechanisms are not well understood. Here, we used the Drosophila melanogaster animal model to study the effects of early-life exercise training (ELET) on the aging heart and lifespan. We found in flies that age-induced arrhythmias are conserved across different genetic backgrounds. The fat body is the primary source of circulating lipoproteins in flies. Inhibition of fat body apoLpp (the flies apoB homolog) demonstrated that low expression of apoLpp reduced the development of arrhythmias in aged flies but did not affect average lifespan. At the same time, ELET can also reduce the expression of apoLpp mRNA in aged flies and have a protective effect on the heart, which is similar to the inhibition of apoLpp mRNA. Although treatment of apoLppRNAi and ELET alone had no significant effect on lifespan, the combination of apoLppRNAi and ELET extended the average lifespan of flies. Therefore, we conclude that apoLppRNAi and ELET are sufficient to resist age-induced arrhythmias, which may be related to the decreased expression of apoLpp mRNA, and that apoLppRNAi and ELET have a combined effect on prolonging the average lifespan.

Atherogenic lipoproteins may impair vascular reactivity, leading to tissue damage in various organs, including the eye. This study aimed to investigate whether ophthalmic artery reactivity is affected in mice lacking the apolipoprotein E gene (ApoE-/-), a model for hypercholesterolemia and atherosclerosis. Twelve-month-old male ApoE-/- mice and age-matched wild-type controls were used to assess vascular reactivity using videomicroscopy. Moreover, vascular mechanics, lipid content, levels of reactive oxygen species (ROS), expression of pro-oxidant redox enzymes and of the lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) were determined in vascular tissue. Unlike the aorta, the ophthalmic artery of ApoE-/- mice developed no signs of endothelial dysfunction and no signs of excessive lipid deposition. Remarkably, levels of ROS, nicotinamide adenine dinucleotide phosphate oxidase 1 (NOX1), NOX2, NOX4, and of LOX-1 were increased in the aorta but not in the ophthalmic artery of ApoE-/- mice. Our findings suggest that ApoE-/- mice develop endothelial dysfunction in the aorta by increased oxidative stress via involvement of LOX-1, NOX1 and NOX2, whereas NOX4 may participate in media remodeling. In contrast, the ophthalmic artery appears to be resistant to chronic apolipoprotein E deficiency. Lack of LOX-1 expression/overexpression in response to increased ox-LDL levels may be a possible mechanism of action.

Background: The Apolipoprotein E4 (ApoE4) genotype is strongly associated with Alzheimer’s disease (AD), although the presence of the ApoE4 allele alone is not sufficient to explain AD. The pathophysiology of amnestic mild cognitive impairment (aMCI) remains unclear. This study aims to examine associations between peripheral blood biomarkers coupled with ApoE4 and episodic and semantic memory. Methods: The CERAD battery was completed and various biomarkers were assayed in 60 subjects with aMCI, 60 with AD and 62 healthy controls. Results: Deficits in semantic and episodic memory were significantly predicted by anion gap and bicarbonate, albumin and glucose coupled with Apo E4. Furthermore, these peripheral biomarkers interacted with ApoE to predict greater memory impairments. Conclusions: Peripheral blood biomarkers may interact with pathways related to ApoE4 to predict greater semantic and episodic memory impairments, thus contributing to the pathophysiology of aMCI and AD. Our data suggest that the transition from aMCI to AD could at least in some cases be associated with significant interactions between ApoE4 and those peripheral blood biomarkers.

End-stage heart failure (ESHF) leads to hypoperfusion and edema formation in the whole body and is accompanied by neurohormonal and immunological alterations. Orthotopic heart transplantation (HTX) has been used as a beneficial option for ESHF. Due to the shortage of donor hearts, the ideal matching and timing of donors and recipients has become more important. Our aim was to explore the relationship between the clinical outcome of HTX and the cytokine and apolipoprotein profiles of the recipient pericardial fluid obtained at transplantation after opening the pericardial sac. The clinical data and the interleukin, adipokine and lipoprotein levels in the pericardial fluid of twenty recipients were investigated. Outcome variables included primer graft dysfunction (PGD), need for posttransplantation mechanical cardiac support (MCS), International Society for Heart and Lung Transplantation grade ≥ 2R rejection and mortality. Recipient risk scores were also investigated. Leptin levels were significantly lower in patients with PGD than in those without PGD (median: 6.36 [IQR: 5.55-6.62]; versus 7.54 [IQR=6.71-10.44]; p = 0.029). Higher ApoCII levels (median: 14.91 [IQR: 11.55-21.30] versus 10.31 [IQR=10.02-13.07]; p = 0.042) and ApoCIII levels (median: 60.32 [IQR: 43.00-81.66] versus 22.84 [IQR=15.84-33.39]; p=0.005) were found in patients (n=5) who died in the first 5 years after HTX. In patients who had rejection (n=4) in the first month after transplantation, the levels of adiponectin (median: 74.48 [IQR: 35.51-131.70] versus 29.96 [IQR: 19.86-42.28]; p=0.039), ApoCII (median: 20.11 [IQR: 13.06-23.54] versus 10.32 [IQR: 10.02-12.84]; p=0.007) and ApoCIII (median: 70.97 [IQR: 34.72-82.22] versus 26.33 [IQR: 17.18-40.17; p=0.029) were higher than those in the nonrejection group. Moreover, the pericardial thyroxine (T4) levels (median: 3.96 [IQR: 3.49-4.46] versus 4.69 [IQR: 4.23-5.77]; p=0.022) were lower in patients with rejection than in patients who did not develop rejection. Our results indicate that apolipoproteins can facilitate the monitoring of rejection and could be a useful tool in the forecast of early and late complications.

Background: Biomarkers are essential for identification of individuals at high risk of mild cognitive impairment (MCI) for potential prevention of dementia. We investigated DNA methylation in the ApoE gene and plasmatic apolipoprotein E (ApoE) levels as MCI biomarkers in Colombian subjects with MCI and controls. Methods: 100 participants were included (71% women, average age, 70 yrs., range 43-91). MCI was diagnosed by neuropsychological testing, medical and social history, activities of daily living, cognitive symptoms and neuroimaging. Multivariate logistic regression models adjusted by age and gender were performed to examine the risk association of MCI with plasma ApoE and APOE methylation Results: MCI was diagnosed in 41 subjects (average age, 66.5±9.6 yrs.) and compared with 59 controls. Elevated plasma ApoE and APOE methylation of CpGs 165, 190, and 198 were risk factors for MCI (P<0.05). Higher CpG-227 methylation correlated with lower risk for MCI (P=0.002). Only CpG-227 was significantly correlated with plasmatic ApoE levels (correlation coefficient=-0.665; P=0.008). Conclusion: Differential APOE methylation and increased plasma ApoE levels were correlated with MCI. These epigenetic patterns can be used as potential biomarkers to identify early stages of MCI.

Glycated hemoglobin (HbA1c) is used to assess glycemic control in Type 1 diabetes (DM1) patients. Apolipoproteins play an essential role in DM1 pathophysiology and may be associated with complications, as well as HbA1c. This cross-sectional observational study consisting of 81 children and adolescents of both sexes diagnosed with DM1 investigated the relationship between body fat distribution and lean mass with HbA1C and apolipoprotein values analyzing biochemical and body composition measurements. Shapiro-Wilk test with Lilliefors correction, non-parametric Mann-Whitney test, and others were used with a significance level of 5%. The sample had a diagnosis time of 4.32 years and high blood glucose levels (mean 178.19 mg/dL) and HbA1c (mean 8.57%). Subjects also had a moderate level of adiposity, as indicated by arm and thigh fat areas. The study also found significant differences in the distribution of patients concerning levels of apolipoproteins A and B, with a smaller proportion of patients having undesirable levels. Finally, the study found a significant difference in the distribution of patients with estimated cardiovascular risk based on the ApoB/ApoA-1 ratio. Conclusively, visceral fat in children and adolescents with DM1 may increase the risk of DM1 long-term complications owing to its association with elevated HbA1C and apolipoprotein values.

Obesity and overweight are associated with many metabolic diseases, such as hypertension, diabetes, and dyslipidemia, which are closely related to a sedentary lifestyle and lack of exercise. Aerobic exercise effectively increases the high-density lipoproteins-cholesterol (HDL-C) levels and decreases the triglyceride (TG) levels. The consumption of Cuban policosanol (Raydel®) is also effective in enhancing the HDL-C quantity and HDL functionality to treat dyslipidemia and hypertension. On the other hand, no study has examined the effects of a combination of high-intensity exercise and policosanol consumption in obese subjects to improve metabolic disorders. In the current study, 17 obese subjects (average BMI 30.0±1.1 kg/m2, eight male and nine female) were recruited to participate in a program combining exercise and policosanol (20 mg) consumption for 12 weeks. After completion, their BMI, waist circumference, total fat mass, systolic blood pressure (SBP), and diastolic blood pressure (DBP) decreased by approximately 15% (p=0.022), 12.7% (p=0.008), 33% (p=0.006), 11% (p<0.046), and 13% (p=0.007), respectively. In the serum lipid profile, at week 12, they showed a remarkable decrease in the total cholesterol (TC) and triglyceride (TG) levels, up to 17% (p<0.019) and 54% (p<0.002) from the baseline, respectively. Although the serum HDL-C was increased by approximately +12% from the baseline, the percentage of HDL-C in TC, HDL-C/TC (%), was increased by up to +32% (p=0.007) at week 12. The serum coenzyme Q10 (CoQ10) level was increased 1.2-fold in all participants at week 12 from the baseline. In particular, the male participants showed a 1.4-fold increase (p=0.027) from the baseline. The larger increase in serum CoQ10 was correlated with the larger increase in the serum HDL-C during 12 weeks. The hepatic function parameters were improved; the serum -glutamyl transferase decreased at week 12 by up to 55% (p<0.007), while the aspartate aminotransferase and alanine transaminase levels decreased within the normal range. In the lipoprotein level, the extent of oxidation and glycation were reduced significantly in VLDL and LDL, with a remarkable decrease in the TG content in particles. The antioxidant abilities of HDL2 and HDL3, such as paraoxonase (PON) and ferric ion reduction ability (FRA), were enhanced significantly by up to 1.8-fold (p<0.001) and 1.6-fold (p<0.001) at week 12. The particle size and number of HDL2 were increased up to +10% during the 12 weeks with a remarkable decrease in the TG content, glycation extent, oxidation up to 32% (p=0.032), 18% (p=0.043), and 11% (p=0.023), respectively. The particle number and diameter of HDL3 were increased by up to +9% with a remarkable increase in the PON activity, FRA activity, and TC content of +82% (p<0.001), +56% (p<0.001), and +32% (p=0.009), respectively. Expression of apolipoproteinA-I in HDL2 and HDL3 were significantly elevated more in both gender around 30~48% with more distinct band intensity and less glycation at week 12. These improvements in HDL quality and functionality were linked to the higher survivability of adult zebrafish and their embryos. Under the co-presence of carboxymethyllysine (CML), a microinjection of HDL2 to zebrafish embryo from week 0 resulted in approximately 47% survivability with developmental defects and attenuated speed. On the other hand, the HDL2 microinjection from week 12 resulted in remarkably higher survivability (~ 70%). In conclusion, 12 weeks of Cuban policosanol (Raydel®, 20 mg) consumption with high-intensity exercise showed significant improvement in blood pressure, body fat mass, blood lipid profile without liver damage, CoQ10 metabolism, and renal impairment. At week 12, all participants showed a remarkable decrease in oxidation and glycation extent in the VLDL and LDL with a decrease in the TC and TG content. Significant enhancement of the qualities and functionalities in HDL2 and HDL3 by the policosanol consumption were also detected: increase in apoA-I content, TC content, particle size, and particle numbers along with antioxidant abilities, such as PON and FRA.

Sporadic Alzheimer’s disease (AD) derives from an interplay among environmental factors and genetic variants, while epigenetic modifications have been expected to affect the onset and progression of its complex etiopathology. Heterozygous carriers of the apolipoprotein E gene (APOE)4 allele have a 4-fold increased risk of developing AD, while APOE 4/4-carriers have a 12-fold increased risk in comparison with the APOE 3-carriers. The main longevity factor is the homozygous APOE ε3/ε3 genotype. In the present narrative review article, we summarized and described the role of APOE epigenetics in aging and AD pathophysiology. It is not fully understood how APOE variants may increase or decrease AD risk, but this gene is known to affect amyloid- and tau-mediated neurodegeneration directly or indirectly, also by affecting lipid metabolism and inflammation. For sporadic AD, epigenetic regulatory mechanisms may control and influence APOE expression in response to external insults. Diet, a major environmental factor, has been significant associated with physical exercise, cognitive function, and the methylation level of several cytosine-phosphate-guanine (CpG) dinucleotides sites of APOE.

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of death worldwide and the risk of a major cardiovascular event is highest among those with established disease. Ongoing management of these patients relies on the accurate assessment of their response to any prescribed therapy, and their residual risk, in order to optimize treatment. Recent international guidelines and position statements concur that the plasma concentration of apolipoprotein B (apoB) is the most accurate measure of lipoprotein associated ASCVD risk. This is especially true for the growing number of individuals with diabetes, obesity or the metabolic syndrome, and those on statin therapy. Most guidelines, however, continue to promote LDL-C as the primary risk marker due to uncertainty as to whether the greater accuracy of apoB is sufficient to warrant a paradigm shift. Recommendations regarding apoB measurement vary, and the information provided on how to interpret apoB results is sometimes insufficient, particularly for the non-lipid specialist. Misinformation regarding the reliability of the assays is also frequently repeated despite its equivalent or better standardization than many other diagnostic assays. Thus, demand for apoB testing is relatively low, which means there is little incentive to increase its availability or reduce its cost. In this review, we examine the results of recent clinical outcomes studies and meta-analyses on the relative values of apoB, LDL-C and non-HDL-C as markers of ASCVD risk. Although there is seemingly minimal difference among these markers when only population-based metrics are considered, it is evident from our analysis that, from a personalized or precision medicine standpoint, a great many individuals would benefit, at a negligible total cost, if apoB measurement were better integrated into the diagnosis and treatment of ASCVD.

Infertility affects millions worldwide, posing a significant global health challenge. The proteomic analysis of follicular fluid provides a comprehensive view of the complex molecular landscape within ovarian follicles, offering valuable information on the factors influencing oocyte development and on the overall reproductive health. The follicular fluid is derived from the plasma and contains various proteins that can have different roles in oocyte health and infertility and this fluid is a critical microenvironment for the developing oocytes as well. Using HPLC/MS method we investigated the protein composition of the follicular fluid and after classification we did relative quantification of the identified proteins in the pregnant (P) and non-pregnant (NP) groups. Based on the protein-protein interaction analysis ALB and ApoA1 was found to be hub proteins and the quantitative comparison of the P and NP groups resulted significantly lower concentration of ApoA1 and HDL-cholesterol in the P group. As both molecules are involved in the cholesterol transport, we also investigated their role in the development of oocytes and in the prediction of fertility.

Background: Studies exploring the possible protective effect of coffee and tea consumption on dementia showed inconsistent results so far. We aimed to investigate whether consumption of tea and different types of coffee at midlife are associated with dementia later in life and, whether sex or ApoE4 influence such association. Methods: We included 7381 participants from the Norwegian HUNT Study. Self-reported questionnaires assessed daily consumption of coffee and tea at baseline. After 22 years, individuals 70 years or older were screened on cognitive impairment. Results: General coffee consumption and tea consumption was not associated with dementia risk. Compared to daily consumption of 0-1 cups of coffee, daily consumption of ≥8 cups of boiled coffee was associated with increased dementia risk in women (OR:1.83, 95% CI: 1.10-3.04, p-value for trend=0.03) and daily consumption of 4-5 cups of other types of coffee was associated with a decrease in dementia risk in only men (OR 0.48, 95% CI: 0.32-0.72, p-value for trend =0.05). Furthermore, the association between boiled coffee and increased dementia risk was only found in ApoE4 non-carriers. Differences by sex or ApoE4 carrier status were not supported by strong statistical evidence for interaction. Conclusion: Type of coffee may play a role in the direction of the association between coffee-drinking habits and dementia later in life.

In the present study, we studied the effect of apolipoprotein A-1 (APOA1) on the spatial and molecular characteristics of bone marrow adipocytes, using well-characterized ApoA1 knockout mice. APOA1 is a central regulator of high-density lipoprotein cholesterol (HDL-C) metabolism, and thus HDL; our recent work showed that deficiency of APOA1 increases bone marrow adiposity in mice. We found that ApoA1 deficient mice have greatly elevated adipocytes within their bone marrow compared to wild type counterparts. Morphologically, the increased adipocytes were similar to white adipocytes, and displayed proximal tibial-end localization. Marrow adipocytes from wild type mice were significantly fewer and did not display bone-end distribution pattern. The mRNA levels of the brown/beige adipocyte-specific markers Ucp1, Dio2, Pat2, Pgc1a, and the expression of leptin were greatly reduced in the ApoA1 knock-out in comparison to the wild-type mice. In the knock-out mice adiponectin was remarkably elevated. In keeping with the close ties of hematopoietic stem cells and marrow adipocytes, we found that the elevated adiposity in the ApoA1 knock out mice is associated with a significant reduction of the hematopoietic stem cells and common myeloid, but not common lymphoid, progenitors. Moreover, the “beiging”-related marker osteopontin and the angiogenic factor VEGF were also reduced in the ApoA1 knock-out mice, further supporting the notion that APOA1, and most probably HDL-C, regulate bone marrow microenvironment, favouring beige/brown adipocyte characteristics.

Genetic variations at the Apolipoprotein E (ApoE) and microtubule-associated protein tau (MAPT) loci have been implicated in multiple neurogenerative diseases, but their exact molecular mechanisms are unclear. In this study we performed transcript level linear modelling using the blood whole transcriptome data and genotypes of the 570 subjects in the Parkinson’s progression markers initiative (PPMI) cohort. ApoE, MAPT haplotypes and two SNPs at the SNCA locus (rs356181, rs3910105) were used to detect expression quantitative trait loci eQTLs associated with the transcriptome and differential usage of transcript isoforms. As a result, we identified 151 genes associated with the genotypic variations, 29 cis and 122 trans eQTL positions. Profound effect with genome-wide significance of ApoE e4 haplotype on the expression of TOMM40 transcripts was identified. This finding potentially explain in part the frequently established genetic association with the APOE e4 haplotypes in neurodegenerative diseases. Moreover, MAPT haplotypes had significant differential impact on 23 transcripts from the 17q21.31 and 17q24.1 loci. MAPT haplotypes had also the largest (256) and smallest (-178) effect sizes measured as beta values on two different transcripts from the same gene (LRRC37A2). Intronic SNP in the SNCA gene, rs3910105, differentially induces expression of three SNCA isoforms. In conclusion, this study established clear association between well-known haplotypic variance and transcript specific regulation in the blood. APOE e4 and MAPT H1/H2 haplotypic variants are associated with the expression of several genes related to the neurodegeneration.

Myr47 lipopeptide consisting of hepatitis B virus (HBV) pre-S1 domain (myristoylated 2-48 peptide) is a commercialized effective anti-HBV drug, preventing the interaction of HBV with sodium taurocholate cotransporting polypeptide (NTCP) on human hepatocytes, of which the activity requires both N-myristoylation residue and specific amino acid sequence. Meanwhile, we recently reported that Myr47 reduces the cellular uptake of HBV surface antigen (HBsAg, subviral particle of HBV) in the absence of NTCP expression (Somiya; et al. Virology 2016, 497, 23–32). In this study, we analyzed how Myr47 reduces the cellular uptake of lipid nanoparticles (including liposomes (LPs) and HBsAg) without NTCP expression. By using Myr47 mutants lacking the HBV infection inhibitory activity, they could reduce the cellular uptake of LPs in an N-myristoylation-dependent manner whereas in an amino acid sequence-independent manner. Moreover, Myr47 and its mutants could reduce the interaction of LPs with apolipoprotein E3 (ApoE3) in an N-myristoylation-dependent manner regardless of their amino acid sequences. From these results, N-myristoyl residue of lipopeptides generally could interfere the LPs/HBsAg-ApoE3 complex formation, thereby reducing the cellular uptake of LPs/HBsAg. When lipid nanoparticles are used as a DDS (drug delivery system) nanocarrier, the surface modification with lipopeptides may be a new method to inhibit unwanted cellular uptake of DDS nanocarriers by non-target cells.