Apolipoproteins AI and E are associated with neuroaxonal injury to gray matter in multiple sclerosis

Lipid and brain volumetric measures in multiple sclerosis patients: findings from a large observational study

OBJECTIVES

This study aimed to investigate relationships between cholesterol profile, brain volumetric MRI, and clinical measures in a large observational cohort of multiple sclerosis (MS) patients.

MATERIALS AND METHODS

We included 1.505 patients with 4.966 time points including complete lipid, clinical, and imaging data. The time among lipid, brain MRI and clinical measures was under 90 days. Cross-sectional statistical analysis at baseline was performed using an adjusted linear regression and analysis of longitudinal lipid and MRI measures data was performed using adjusted linear mixed models.

RESULTS

We found associations between higher high-density lipoprotein cholesterol (HDL-C) and lower brain parenchymal fraction (BPF) at cross-sectional analysis at baseline (B = -0.43, CI 95%: -0.73, -0.12, p = 0.005), as well as in longitudinal analysis over follow-up (B = -0.32 ± 0.072, χ2 = 36.6; p = < 0.001). Higher HDL-C was also associated with higher T2-lesion volume in longitudinal analysis (B = 0.11 ± 0.023; χ2 = 23.04; p = < 0.001). We observed a weak negative association between low-density lipoprotein cholesterol (LDL-C) levels and BPF at baseline (B = -0.26, CI 95%: -0.4, -0.11, p = < 0.001) as well as in longitudinal analysis (B = -0.06 ± 0.03, χ2 = 4.46; p = 0.03). T2-LV did not show an association with LDL-C. We did not find any association between lipid measures and disability. The effect of lipid levels on MRI measures and disability was minimal (Cohen f2 < 0.02).

CONCLUSIONS

Our results contradict the previously described exclusively positive effect of HDL-C on brain atrophy in patients with MS. Higher LDL-C was weakly associated with higher brain atrophy but not with higher lesion burden.

Prospective outcome analysis of multiple sclerosis cases reveals candidate prognostic cerebrospinal fluid markers

BACKGROUND

Predicting the long-term disability outcomes of multiple sclerosis (MS) cases is challenging.

OBJECTIVE

We prospectively analysed our previous MS cohort with initial cerebrospinal fluid (CSF) proteomics data to reveal disability markers after 8.2±2.2 years of follow-up.

METHODS

Patients with regular follow-up visits were assigned into two groups: those with an age-related MS severity (ARMSS) score ≥5 (unfavourable course group, N = 27) and ARMSS score <5 (favourable course group, N = 67). A machine learning-based algorithm was applied to reveal candidate poor prognosis-associated initial CSF proteins, which were measured in an independent MS cohort (verification group, N = 40) by ELISA. Additionally, the correlation of initial clinical and radiological parameters with long-term disability was analysed.

RESULTS

CSF alpha-2-macroglobulin (P = 0.0015), apo-A1 (P = 0.0016), and haptoglobin (P = 0.0003) protein levels, as well as cerebral lesion load (>9 lesions) on magnetic resonance imaging, gait disturbance (P = 0.04), and bladder/bowel symptoms (P = 0.01) were significantly higher in the unfavourable course group than in the favourable course group. Optic nerve involvement evident on initial magnetic resonance imaging (P = 0.002) and optic neuritis (P = 0.01) were more frequent in the favourable course group.

CONCLUSION

The herein identified initial CSF protein levels, in addition to the clinical and radiological parameters at disease onset, have predictive value for long-term disability in MS cases.

Cholesterol pathway biomarkers are associated with neuropsychological measures in multiple sclerosis

BACKGROUND

Cognitive impairment (CI) is frequent in persons with multiple sclerosis (PwMS) and is linked to neurodegeneration. Cholesterol pathway biomarkers (CPB) are associated with blood-brain barrier breakdown, lesions, and neurodegeneration in multiple sclerosis (MS). CPB could influence CI.

METHODS

This cross-sectional study (n = 163) included 74 relapsing-remitting MS (RR-MS), 48 progressive MS (P-MS) and 41 healthy control (HC) subjects. The assessed physical disability and cognitive measures were: Nine-hole Peg Test (NHPT), Timed 25-Foot Walk, Symbol Digit Modalities Test (SDMT), Paced Auditory Serial Addition Test-3, and Beck Depression Inventory-Fast Screen. CPB panel included plasma total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and the apolipoproteins (Apo), ApoA-I, ApoA-II, ApoB, ApoC-II and ApoE. Disability and cognitive measures were assessed as dependent variables in regression analyzes with age, sex, body mass index, years of education, HC vs. RR-MS vs. P-MS status, CPB, and a HC vs. RR-MS vs. P-MS status × CPB interaction term as predictors.

RESULTS

SDMT was associated with the interaction terms for HDL-C (p = 0.045), ApoA-I (p = 0.032), ApoB (p = 0.032), TC/HDL-C (p = 0.013), and ApoB/ApoA-I (p = 0.008) ratios. CPB associations of SDMT were not abrogated upon adjusting for brain parenchymal volume. NHPT performance was associated with the interaction terms for TC (p = 0.047), LDL-C (p = 0.017), ApoB (p = 0.001), HDL-C (p = 0.035), ApoA-I (p = 0.032), ApoC-II (p = 0.049) and ApoE (p = 0.037), TC/HDL-C (p < 0.001), and ApoB/ApoA-I ratios (p < 0.001).

CONCLUSIONS

The LDL to HDL proportion is associated with SDMT and NHPT in MS. The findings are consistent with a potential role for CPB in CI.

Fingolimod treatment modulates PPARγ and CD36 gene expression in women with multiple sclerosis

Fingolimod is an oral immunomodulatory drug used in the treatment of multiple sclerosis (MS) that may change lipid metabolism. Peroxisome proliferator-activated receptors (PPAR) are transcription factors that regulate lipoprotein metabolism and immune functions and have been implicated in the pathophysiology of MS. CD36 is a scavenger receptor whose transcription is PPAR regulated. The objective of this study was to evaluate whether fingolimod treatment modifies PPAR and CD36 gene expression as part of its action mechanisms. Serum lipoprotein profiles and PPAR and CD36 gene expression levels in peripheral leukocytes were analysed in 17 female MS patients before and at 6 and 12 months after fingolimod treatment initiation. Clinical data during the follow-up period of treatment were obtained. We found that fingolimod treatment increased HDL-Cholesterol and Apolipoprotein E levels and leukocyte PPARγ and CD36 gene expression. No correlations were found between lipid levels and variations in PPARγ and CD36 gene expression. PPARγ and CD36 variations were significantly correlated during therapy and in patients free of relapse and stable disease. Our results suggest that PPARγ and CD36-mediated processes may contribute to the mechanisms of action of fingolimod in MS. Further studies are required to explore the relation of the PPARγ/CD36 pathway to the clinical efficacy of the drug and its involvement in the pathogenesis of the disease.

New Insights into Multiple Sclerosis Mechanisms: Lipids on the Track to Control Inflammation and Neurodegeneration

Multiple sclerosis (MS) is a central nervous system disease with complex pathogenesis, including two main processes: immune-mediated inflammatory demyelination and progressive degeneration with axonal loss. Despite recent progress in our understanding and management of MS, availability of sensitive and specific biomarkers for these both processes, as well as neuroprotective therapeutic options targeted at progressive phase of disease, are still being sought. Given their abundance in the myelin sheath, lipids are believed to play a central role in underlying immunopathogenesis in MS and seem to be a promising subject of investigation in this field. On the basis of our previous research and a review of the literature, we discuss the current understanding of lipid-related mechanisms involved in active relapse, remission, and progression of MS. These insights highlight potential usefulness of lipid markers in prediction or monitoring the course of MS, particularly in its progressive stage, still insufficiently addressed. Furthermore, they raise hope for new, effective, and stage-specific treatment options, involving lipids as targets or carriers of therapeutic agents.

Disease biomarkers in multiple sclerosis: current serum neurofilament light chain perspectives

The continuous neuroinflammatory and neurodegenerative pathology in multiple sclerosis (MS) results in irreversible accumulation of physical and cognitive disability. Reliable early detection of MS disease processes can aid in the diagnosis, monitoring and treatment management of MS patients. Recent assay technological advancements now allow reliable quantification of serum-based neurofilament light chain (sNfL) levels, which provide temporal information regarding the degree of neuroaxonal damage. The relationship and predictive value of sNfL with clinical and cognitive outcomes, other paraclinical measures and treatment response is reviewed. sNfL measurement is an emerging, noninvasive and disease-responsive MS biomarker that is currently utilized in research and clinical trial settings. Understanding sNfL confounders and further assay standardization will allow clinical implementation of this biomarker.

The cholesterol autoxidation products, 7-ketocholesterol and 7β-hydroxycholesterol are associated with serum neurofilaments in multiple sclerosis

BACKGROUND

Serum neurofilament light chain (sNfL) is an established marker of neuroaxonal injury in multiple sclerosis (MS).

OBJECTIVES

To investigate if oxysterols produced from non-enzymatic and enzymatic cholesterol oxidation are differentially associated with sNfL measurements in MS.

METHODS

This longitudinal study included 62 relapsing-remitting (RR-MS) and 36 progressive MS (PMS) patients with baseline and 5-year follow-up measures of serum levels of 6 oxysterols, sNfL and lipids. The oxysterols, 24-hydroxycholesterol (24HC), 25HC, 27HC, 7αHC, 7βHC and 7-ketocholesterol (7KC), were measured using liquid chromatography-mass spectrometry. sNfL was measured using single molecular array assay. Serum high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels were obtained from a lipid profile.

RESULTS

The enzymatically produced oxysterols 24HC, 25HC, 27HC and 7αHC were not associated with sNfL. However, baseline levels of reactive oxygen species (ROS) produced oxysterols, 7KC (p = 0.032) and 7βHC (p = 0.0025), were positively associated with sNfL levels at follow-up. Follow-up 7KC (p = 0.038) levels were also associated with follow-up sNfL levels. The associations of 7KC or 7βHC with sNfL remained significant after adjusting for LDL-C or HDL-C.

CONCLUSIONS

7KC and 7βHC, produced by ROS-mediated cholesterol oxidation are associated with neuroaxonal injury as assessed by sNfL in MS.

Association of Gene Polymorphisms in APOE and BIN1 With Dementia of Alzheimer's Type Susceptibility in Chinese Han Population

Objectives: Dementia of the Alzheimer's type (DAT) is the most common chronic neurodegenerative disease. At present, the pathogenesis of DAT is not completely clear, and there are no drugs that can cure the disease. Once an individual is diagnosed with DAT, the survival time is only 3 to 9 years. Therefore, there is an urgent need to determine the etiology of DAT and the associated influencing factors to find a breakthrough in the treatment of DAT. Methods: We studied the relationship between polymorphisms in several genes (including BIN1 and APOE) and DAT susceptibility and the effects of sex differences on DAT. Our study included 137 patients with DAT and 509 healthy controls (HCs). Results: The APOE rs429358 polymorphism CC and CT genotypes were associated with an increased risk of DAT in women. We found a significant association between APOE ε4 and DAT. The frequency of the ε4 allele in the DAT group (15.5%) was higher than that in the HC group (8.7%). The BIN1 rs7561528 polymorphism was associated with a decreased risk of DAT in men. Conclusions: APOE gene rs429358 and BIN1 gene 7561528 genes may affect the susceptibility to DAT in a Chinese Han population.

Paraoxonase Role in Human Neurodegenerative Diseases

The human body has biological redox systems capable of preventing or mitigating the damage caused by increased oxidative stress throughout life. One of them are the paraoxonase (PON) enzymes. The PONs genetic cluster is made up of three members (PON1, PON2, PON3) that share a structural homology, located adjacent to chromosome seven. The most studied enzyme is PON1, which is associated with high density lipoprotein (HDL), having paraoxonase, arylesterase and lactonase activities. Due to these characteristics, the enzyme PON1 has been associated with the development of neurodegenerative diseases. Here we update the knowledge about the association of PON enzymes and their polymorphisms and the development of multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD) and Parkinson's disease (PD).

High density lipoprotein cholesterol and apolipoprotein A-I are associated with greater cerebral perfusion in multiple sclerosis

BACKGROUND

The pathophysiological mechanisms underlying the associations of multiple sclerosis (MS) neurodegeneration serum cholesterol profiles is currently unknown.

OBJECTIVE

To determine associations between lipid profile measures and cerebral perfusion-based indices in MS patients.

METHODS

Seventy-seven MS patients underwent 3 T MRI. Cerebral blood volume (CBV), time-to-peak (TTP) and mean transit time (MTT) measures were computed from dynamic susceptibility contrast (DSC) perfusion-weighted imaging (PWI) for normal-appearing brain tissue (NABT), GM, cortex, deep gray matter (DGM) and thalamus. Total cholesterol, low and high-density lipoprotein cholesterol (LDL-C and HDL-C) and the apolipoproteins (Apo), ApoA-I, ApoA-II, ApoB, ApoC-II and ApoE levels were measured in plasma. Age and body mass index (BMI)-adjusted correlations were used to assess the associations between PWI and lipid profile measures.

RESULTS

Higher HDL-C levels were associated with shorter MTT, which are indicative of greater perfusion, in NABT (p = 0.012), NAWM (p = 0.021), GM (p = 0.009), cortex (p = 0.014), DGM p = 0.015; and thalamus p = 0.015). The HDL-C-associated apolipoproteins, ApoA-I and ApoA-II, were associated with shorter MTT of the same brain regions (all p < 0.028). HDL-C and ApoA-I levels were also associated with shorter TTP, indicative of faster cerebral blood delivery. ApoC-II was associated with lower nCBV of the GM and cortex (p = 0.035 and p = 0.014, respectively).

CONCLUSION

The HDL pathway is associated with better global brain perfusion and faster cerebral blood delivery as measured by shorter MTT and TTP, respectively. ApoC-II may be associated with lower cortical and DGM perfusion.

Increased Pro-Thrombotic Platelet Activity Associated with Thrombin/PAR1-Dependent Pathway Disorder in Patients with Secondary Progressive Multiple Sclerosis

Epidemiological studies confirm the high risk of ischemic events in multiple sclerosis (MS) that are associated with increased pro-thrombotic activity of blood platelets. The most potent physiological platelet agonist is thrombin, which activates platelets via cleavage of specific protease-activated receptors (PARs). Our current study is aimed to determine the potential genetics and proteomic abnormalities of PAR1 in both platelets and megakaryocytes, which may have thromboembolic consequences in the course of MS. The obtained results were correlated with the expression level of platelet and megakaryocyte transcripts for APOA1 and A2M genes encoding atherosclerosis biomarkers: apolipoprotein A1 (ApoA1) and α-2-macroglobulin (α2M), respectively. Moreover, PAR1 functionality in MS platelets was assessed by flow cytometry, determining the level of platelet–platelet and platelet–leukocyte aggregates, platelet microparticles and surface expression of P-selectin. As a PAR1 agonist, the synthetic TRAP-6 peptide was used, which made it possible to achieve platelet activation in whole blood without triggering clotting. Comparative analyses showed an elevated level of platelet activation markers in the blood of MS patients compared to controls. The mRNA expression of gene coding α2M was upregulated, whilst ApoA1 was down-regulated, both in platelets and megakaryocytes from MS patients. Furthermore, we observed an increase in both mRNA expression and surface density of PAR1 in platelets and megakaryocytes in MS compared to controls. Both the level of platelet activation markers and PAR1 expression showed a high correlation with the expression of transcripts for APOA1 and A2M genes.