Transcriptomic changes in oligodendrocyte lineage cells during the juvenile to adult transition in the mouse corpus callosum.

The corpus callosum, a major white matter tract in the brain, undergoes age-related functional changes. To extend our investigation of age-related gene expression dynamics in the mouse corpus callosum, we compared RNA-seq data from 2 week-old and 12 week-old wild-type C57BL/6 J mice and identified the differentially expressed genes (e.g., Marcksl1, Chst3, C4b, Neat1, Ndrg1, Emid1, etc.) between these ages. Interestingly, we found that genes highly expressed in myelinating oligodendrocytes were upregulated in 12 week-old mice compared to 2 week-old mice, while genes highly expressed in oligodendrocyte precursor cells (OPCs) and newly formed oligodendrocytes were downregulated. Furthermore, by comparing these genes with the datasets from 20 week-old and 96 week-old mice, we identified novel sets of genes with age-dependent variations in the corpus callosum. These gene expression changes potentially affect key biological pathways and may be closely linked to age-related neurological disorders, including dementia and stroke. Therefore, our results provide an additional dataset to explore age-dependent gene expression dynamics of oligodendrocyte lineage cells in the corpus callosum.

White matter hyperintensity genetic risk factor TRIM47 regulates autophagy in brain endothelial cells.

White matter hyperintensity (WMH) is strongly correlated with age-related dementia and hypertension, but its pathogenesis remains obscure. Genome-wide association studies identified TRIM47 at the 17q25 locus as a top genetic risk factor for WMH formation. TRIM family is a class of E3 ubiquitin ligase with pivotal functions in autophagy, which is critical for brain endothelial cell (ECs) remodeling during hypertension. We hypothesize that TRIM47 regulates autophagy and its loss-of-function disturbs cerebrovasculature. Based on transcriptomics and immunohistochemistry, TRIM47 is found highly expressed by brain ECs in human and mouse, and its transcription is upregulated by artificially induced autophagy while downregulated in hypertension-like conditions. Using in silico simulation, immunocytochemistry and super-resolution microscopy, we predicted a highly conserved binding site between TRIM47 and the LIR (LC3-interacting region) motif of LC3B. Importantly, pharmacological autophagy induction increased Trim47 expression on mouse ECs (b.End3) culture, while silencing Trim47 significantly increased autophagy with ULK1 phosphorylation induction, transcription, and vacuole formation. Together, we demonstrate that TRIM47 is an endogenous inhibitor of autophagy in brain ECs, and such TRIM47-mediated regulation connects genetic and physiological risk factors for WMH formation but warrants further investigation.

Transcriptomic Profiles of AKAP12 Deficiency in Mouse Corpus Callosum.

A-kinase anchor protein 12 (AKAP12), a scaffold protein, has been implicated in the central nervous system, including blood-brain barrier (BBB) function. Although its expression level in the corpus callosum is higher than in other brain regions, such as the cerebral cortex, the role of AKAP12 in the corpus callosum remains unclear. In this study, we investigate the impact of AKAP12 deficiency by transcriptome analysis using RNA-sequencing (RNA-seq) on the corpus callosum of AKAP12 knockout (KO) mice. We observed minimal changes, with only 13 genes showing differential expression, including Akap12 itself. Notably, Klf2 and Sgk1, genes potentially involved in BBB function, were downregulated in AKAP12 KO mice and expressed in vascular cells similar to Akap12. These changes in gene expression may affect important biological pathways that may be associated with neurological disorders. Our findings provide an additional data set for future research on the role of AKAP12 in the central nervous system.

In vitro cytotoxicity assessment of ruxolitinib on oligodendrocyte precursor cell and neural stem/progenitor cell populations.

JAK-STAT signaling cascade has emerged as an ideal target for the treatment of myeloproliferative diseases, autoimmune diseases, and neurological disorders. Ruxolitinib (Rux), is an orally bioavailable, potent and selective Janus-associated kinase (JAK) inhibitor, proven to be effective to target activated JAK-STAT pathway in the diseases previously described. Unfortunately, limited studies have investigated the potential cytotoxic profile of Rux on other cell populations within the heterogenous CNS microenvironment. Two stem and progenitor cell populations, namely the oligodendrocyte precursor cells (OPCs) and neural stem/progenitor cells (NSPCs), are important for long-term maintenance and post-injury recovery response of the CNS. In light of the limited evidence, this study sought to investigate further the effect of Rux on proliferating and differentiating OPCs and NSPCs populations. In the present study, cultured rat OPCs and NSPCs were treated with various concentrations of Rux, ranging from 2 µM to 20 µM. The effect of Rux on proliferating OPCs (PDGF-R-α+) and proliferating NSPCs (nestin+) was assessed via a 3-day Rux treatment, whereas its effect on differentiating OPCs (MBP+/PDGF-R-α+) and differentiating NSPCs (neurofilament+) was assessed after a 7-day treatment. Cytotoxicity of Rux was also assessed on OPC populations by examining its influence on cell death and DNA synthesis via YO-PRO-1/PI dual-staining and BrdU assay, respectively. The results suggest that Rux at a dosage above 10 µM reduces the number proliferating OPCs, likely via the induction of apoptosis. On the other hand, Rux treatment from 2.5 µM to 20 µM significantly reduces the number of differentiating OPCs by inducing necrosis. Meanwhile, Rux treatment has no observable untoward impact on NSPC cultures within the dosage range tested. Taken together, OPCs appears to be more vulnerable to the dosage effect of Rux, whereas NSPCs are not significantly impacted by Rux, suggesting a differential mechanism of actions of Rux on the cell types.

White matter hyperintensity genetic risk factor TRIM47 regulates autophagy in brain endothelial cells.

White matter hyperintensity (WMH) is strongly correlated with age-related dementia and hypertension, but its pathogenesis remains obscure. GWAS identified TRIM47 at 17q25 locus as a top genetic risk factor for WMH formation. TRIM family is a class of E3 ubiquitin ligase with pivotal functions in autophagy, which is critical for brain endothelial cell (ECs) remodeling during hypertension. We hypothesize that TRIM47 regulates autophagy and its loss-of-function disturbs cerebrovasculature. Based on transcriptomics and immunohistochemistry, TRIM47 is found selectively expressed by brain ECs in human and mouse, and its transcription is upregulated by artificially-induced autophagy while downregulated in hypertension-like conditions. Using in silico simulation, immunocytochemistry and super-resolution microscopy, we identified the highly conserved binding site between TRIM47 and the LIR (LC3-interacting region) motif of LC3B. Importantly, pharmacological autophagy induction increased Trim47 expression on mouse ECs (b.End3) culture, while silencing Trim47 significantly increased autophagy with ULK1 phosphorylation induction, transcription and vacuole formation. Together, we confirm that TRIM47 is an endogenous inhibitor of autophagy in brain ECs, and such TRIM47-mediated regulation connects genetic and physiological risk factors for WMH formation but warrants further investigation. SUMMARY STATEMENT: TRIM47, top genetic risk factor for white matter hyperintensity formation, is a negative regulator of autophagy in brain endothelial cells and implicates a novel cellular mechanism for age-related cerebrovascular changes.

Transcriptomic Profiling Reveals Neuroinflammation in the Corpus Callosum of a Transgenic Mouse Model of Alzheimer's Disease.

BACKGROUND: Alzheimer's disease (AD) is a widespread neurodegenerative disorder characterized by progressive cognitive decline, affecting a significant portion of the aging population. While the cerebral cortex and hippocampus have been the primary focus of AD research, accumulating evidence suggests that white matter lesions in the brain, particularly in the corpus callosum, play an important role in the pathogenesis of the disease. OBJECTIVE: This study aims to investigate the gene expression changes in the corpus callosum of 5xFAD transgenic mice, a widely used AD mouse model. METHODS: We conducted behavioral tests for spatial learning and memory in 5xFAD transgenic mice and performed RNA sequencing analyses on the corpus callosum to examine transcriptomic changes. RESULTS: Our results show cognitive decline and demyelination in the corpus callosum of 5xFAD transgenic mice. Transcriptomic analysis reveals a predominance of upregulated genes in AD mice, particularly those associated with immune cells, including microglia. Conversely, downregulation of genes related to chaperone function and clock genes such as Per1, Per2, and Cry1 is also observed. CONCLUSIONS: This study suggests that activation of neuroinflammation, disruption of chaperone function, and circadian dysfunction are involved in the pathogenesis of white matter lesions in AD. The findings provide insights into potential therapeutic targets and highlight the importance of addressing white matter pathology and circadian dysfunction in AD treatment strategies.

Assessment of Residual Vasospasm in Patients with Plaque Rupture or Plaque Erosion using Optical Coherence Tomography.

AIMS: Coronary vasospasm is associated with acute coronary syndrome (ACS) and may persist during primary percutaneous coronary intervention (PCI). We aimed to elucidate the incidence, morphological characteristics, and prognostic impact of residual vasospasm in plaque rupture (PR) and plaque erosion (PE) lesions using optical coherence tomography (OCT). METHODS: We enrolled 142 patients with ACS who underwent OCT-guided primary PCI. All patients received intracoronary vasodilators before OCT examination. Residual vasospasm was identified as intimal gathering and categorised as polygonal- or wavy- patterned depending on the luminal shape. A wavy pattern was defined as a curved intimal surface line. A polygonal pattern was defined as a lumen with multiple angles. The incidence of major cardiovascular events, defined as death, non-fatal myocardial infarction, stroke, and any revascularization, within 1-year of PCI was identified. RESULTS: The prevalence of residual vasospasm in PR and PE was 15.1% (13 of 86) and 21.4% (12 of 56), respectively. Wavy pattern was the major shape of the residual vasospasm. Polygonal-patterned lumen was more frequently observed in PR than in PE (38.5 vs. 8.3 %). The polygonal-patterned lumens had significantly larger lipid arcs (257.9 vs. 78.0 °; P＜0.01), and significantly smaller areas (1.27 vs. 1.88 mm2; P=0.05) than wavy patterned lumens. Residual vasospasm had a prognostic impact on PR but not PE at 1-year of successful primary PCI. CONCLUSION: Considerable proportion of ACS including both PR and PE had residual vasospasm with variable morphological feature and different prognostic impact.

Myelination- and migration-associated genes are downregulated after phagocytosis in cultured oligodendrocyte precursor cells.

In the central nervous system, microglia are responsible for removing infectious agents, damaged/dead cells, and amyloid plaques by phagocytosis. Other cell types, such as astrocytes, are also recently recognized to show phagocytotic activity under some conditions. Oligodendrocyte precursor cells (OPCs), which belong to the same glial cell family as microglia and astrocytes, may have similar functions. However, it remains largely unknown whether OPCs exhibit phagocytic activity against foreign materials like microglia. To answer this question, we examined the phagocytosis activity of OPCs using primary rat OPC cultures. Since innate phagocytosis activity could trigger cell death pathways, we also investigated whether participating in phagocytosis activity may lead to OPC cell death. Our data shows that cultured OPCs phagocytosed myelin-debris-rich lysates prepared from rat corpus callosum, without progressing to cell death. In contrast to OPCs, mature oligodendrocytes did not show phagocytotic activity against the bait. OPCs also exhibited phagocytosis towards lysates of rat brain cortex and cell membrane debris from cultured astrocytes, but the percentage of OPCs that phagocytosed beta-amyloid was much lower than the myelin debris. We then conducted RNA-seq experiments to examine the transcriptome profile of OPC cultures and found that myelination- and migration-associated genes were downregulated 24 h after phagocytosis. On the other hand, there were a few upregulated genes in OPCs 24 h after phagocytosis. These data confirm that OPCs play a role in debris removal and suggest that OPCs may remain in a quiescent state after phagocytosis.

Aerobic exercise reverses aging-induced depth-dependent decline in cerebral microcirculation.

Aging is a major risk factor for cognitive impairment. Aerobic exercise benefits brain function and may promote cognitive health in older adults. However, underlying biological mechanisms across cerebral gray and white matter are poorly understood. Selective vulnerability of the white matter to small vessel disease and a link between white matter health and cognitive function suggests a potential role for responses in deep cerebral microcirculation. Here, we tested whether aerobic exercise modulates cerebral microcirculatory changes induced by aging. To this end, we carried out a comprehensive quantitative examination of changes in cerebral microvascular physiology in cortical gray and subcortical white matter in mice (3-6 vs. 19-21 months old), and asked whether and how exercise may rescue age-induced deficits. In the sedentary group, aging caused a more severe decline in cerebral microvascular perfusion and oxygenation in deep (infragranular) cortical layers and subcortical white matter compared with superficial (supragranular) cortical layers. Five months of voluntary aerobic exercise partly renormalized microvascular perfusion and oxygenation in aged mice in a depth-dependent manner, and brought these spatial distributions closer to those of young adult sedentary mice. These microcirculatory effects were accompanied by an improvement in cognitive function. Our work demonstrates the selective vulnerability of the deep cortex and subcortical white matter to aging-induced decline in microcirculation, as well as the responsiveness of these regions to aerobic exercise.

Role of A-Kinase Anchoring Protein 12 in the Central Nervous System.

A-kinase anchoring protein (AKAP) 12 is a scaffolding protein that anchors various signaling proteins to the plasma membrane. These signaling proteins include protein kinase A, protein kinase C, protein phosphatase 2B, Src-family kinases, cyclins, and calmodulin, which regulate their respective signaling pathways. AKAP12 expression is observed in the neurons, astrocytes, endothelial cells, pericytes, and oligodendrocytes of the central nervous system (CNS). Its physiological roles include promoting the development of the blood-brain barrier, maintaining white-matter homeostasis, and even regulating complex cognitive functions such as long-term memory formation. Under pathological conditions, dysregulation of AKAP12 expression levels may be involved in the pathology of neurological diseases such as ischemic brain injury and Alzheimer's disease. This minireview aimed to summarize the current literature on the role of AKAP12 in the CNS.

Differential reductions in the capillary red-blood-cell flux between retina and brain under chronic global hypoperfusion.

Significance: It has been hypothesized that abnormal microcirculation in the retina might predict the risk of ischemic damages in the brain. Direct comparison between the retinal and the cerebral microcirculation using similar animal preparation and under similar experimental conditions would help test this hypothesis. Aim: We investigated capillary red-blood-cell (RBC) flux changes under controlled conditions and bilateral-carotid-artery-stenosis (BCAS)-induced hypoperfusion, and then compared them with our previous measurements performed in the brain. Approach: We measured capillary RBC flux in mouse retina with two-photon microscopy using a fluorescence-labeled RBC-passage approach. Key physiological parameters were monitored during experiments to ensure stable physiology. Results: We found that under the controlled conditions, capillary RBC flux in the retina was much higher than in the brain (i.e., cerebral cortical gray matter and subcortical white matter), and that BCAS induced a much larger decrease in capillary RBC flux in the retina than in the brain. Conclusions: We demonstrated a two-photon microscopy-based technique to efficiently measure capillary RBC flux in the retina. Since cerebral subcortical white matter often exhibits early pathological developments due to global hypoperfusion, our results suggest that retinal microcirculation may be utilized as an early marker of brain diseases involving global hypoperfusion.

Rhythms in barriers and fluids: Circadian clock regulation in the aging neurovascular unit.

The neurovascular unit is where two very distinct physiological systems meet: The central nervous system (CNS) and the blood. The permeability of the barriers separating these systems is regulated by time, including both the 24 h circadian clock and the longer processes of aging. An endogenous circadian rhythm regulates the transport of molecules across the blood-brain barrier and the circulation of the cerebrospinal fluid and the glymphatic system. These fluid dynamics change with time of day, and with age, and especially in the context of neurodegeneration. Factors may differ depending on brain region, as can be highlighted by consideration of circadian regulation of the neurovascular niche in white matter. As an example of a potential target for clinical applications, we highlight chaperone-mediated autophagy as one mechanism at the intersection of circadian dysregulation, aging and neurodegenerative disease. In this review we emphasize key areas for future research.

Association between Eicosapentaenoic Acid to Arachidonic Acid Ratio and Characteristics of Plaque Rupture.

AIMS: Eicosapentaenoic acid (EPA) has shown beneficial effects on coronary plaque stabilization. Based on our previous study, we speculated that EPA might be associated with the development of healed plaques and might limit thrombus size. This study aimed to elucidate the association between EPA and arachidonic acid (AA) ratios and various plaque characteristics in patients with plaque rupture. METHODS: A total of 95 patients with acute coronary syndrome (ACS) caused by plaque rupture who did not take lipid-lowering drugs and underwent percutaneous coronary intervention using optical coherence tomography (OCT) were included. Clinical characteristics, lipid profiles, and OCT findings were compared between patients with lower and higher EPA/AA ratios (0.41) according to the levels in the Japanese general population. RESULTS: In the high EPA/AA (n=29, 30.5%) and low EPA/AA (n=66, 69.5 %) groups, the high EPA/AA group was significantly older (76.1 vs. 66.1 years, P＜0.01) and had lower peak creatine kinase (556 vs. 1651 U/L, P=0.03) than those with low EPA/AA. Similarly, patients with high EPA/AA had higher prevalence of layered and calcified plaque (75.9 vs. 39.4 %, P＜0.01; 79.3 vs. 50.0 %, P＜0.01, respectively) than low EPA/AA group. Multivariate logistic regression analysis demonstrated that a high EPA/AA ratio was an independent factor in determining the development of layered and calcified plaques. CONCLUSION: A high EPA/AA ratio may be associated with the development of layered and calcified plaques in patients with plaque rupture.

A brief overview of a mouse model of cerebral hypoperfusion by bilateral carotid artery stenosis.

Vascular cognitive impairment (VCI) refers to all forms of cognitive disorder related to cerebrovascular diseases, including vascular mild cognitive impairment, post-stroke dementia, multi-infarct dementia, subcortical ischemic vascular dementia (SIVD), and mixed dementia. Among the causes of VCI, more attention has been paid to SIVD because the causative cerebral small vessel pathologies are frequently observed in elderly people and because the gradual progression of cognitive decline often mimics Alzheimer's disease. In most cases, small vessel diseases are accompanied by cerebral hypoperfusion. In mice, prolonged cerebral hypoperfusion is induced by bilateral carotid artery stenosis (BCAS) with surgically implanted metal micro-coils. This cerebral hypoperfusion BCAS model was proposed as a SIVD mouse model in 2004, and the spreading use of this mouse SIVD model has provided novel data regarding cognitive dysfunction and histological/genetic changes by cerebral hypoperfusion. Oxidative stress, microvascular injury, excitotoxicity, blood-brain barrier dysfunction, and secondary inflammation may be the main mechanisms of brain damage due to prolonged cerebral hypoperfusion, and some potential therapeutic targets for SIVD have been proposed by using transgenic mice or clinically used drugs in BCAS studies. This review article overviews findings from the studies that used this hypoperfused-SIVD mouse model, which were published between 2004 and 2021.

Aerobic exercise reverses aging-induced depth-dependent decline in cerebral microcirculation.

Aging is a major risk factor for cognitive impairment. Aerobic exercise benefits brain function and may promote cognitive health in older adults. However, underlying biological mechanisms across cerebral gray and white matter are poorly understood. Selective vulnerability of the white matter to small vessel disease and a link between white matter health and cognitive function suggests a potential role for responses in deep cerebral microcirculation. Here, we tested whether aerobic exercise modulates cerebral microcirculatory changes induced by aging. To this end, we carried out a comprehensive quantitative examination of changes in cerebral microvascular physiology in cortical gray and subcortical white matter in mice (3-6 vs. 19-21 months old), and asked whether and how exercise may rescue age-induced deficits. In the sedentary group, aging caused a more severe decline in cerebral microvascular perfusion and oxygenation in deep (infragranular) cortical layers and subcortical white matter compared with superficial (supragranular) cortical layers. Five months of voluntary aerobic exercise partly renormalized microvascular perfusion and oxygenation in aged mice in a depth-dependent manner, and brought these spatial distributions closer to those of young adult sedentary mice. These microcirculatory effects were accompanied by an improvement in cognitive function. Our work demonstrates the selective vulnerability of the deep cortex and subcortical white matter to aging-induced decline in microcirculation, as well as the responsiveness of these regions to aerobic exercise.

Impact of triglyceride-rich lipoproteins on early in-stent neoatherosclerosis formation in patients undergoing statin treatment.

BACKGROUND: Neoatherosclerosis (NA), which refers to neointimal atherosclerosis within a stent, is considered one of the underlying causes of late-phase stent failure following a newer generation drug-eluting stent (DES) placement procedure. Even contemporary guideline-directed medical therapy may be insufficient to prevent NA. OBJECTIVE: This study aimed to investigate how intricately lipid markers are associated with NA formation in the early phase of treatment with well-maintained low-density lipoprotein cholesterol (LDL-C) levels. METHODS: We enrolled 114 consecutive patients undergoing statin treatment and percutaneous coronary intervention (PCI) with current-generation DES for coronary artery disease. At a median 12 months after PCI, optical coherence tomography (OCT) was performed. Various lipid markers, including LDL-C, triglyceride (TG), triglyceride-rich lipoprotein cholesterol (TRL-C), non-high-density lipoprotein cholesterol (non-HDL-C), malondialdehyde-modified LDL (MDA-LDL), and several apolipoproteins, were also evaluated. RESULTS: NA was observed in 17 (14.9%) patients. The LDL-C level was equivalent in patients with or without NA (77.2 vs. 69.8 mg/dL; p=0.15). However, the levels of TG, apolipoprotein C3 (apoC3), TRL-C, non-HDL-C, and apolipoprotein B (apoB), and MDA-LDL were significantly higher in the patients with NA. Furthermore, multivariate logistic regression adjusting for HbA1c and stent duration revealed apoC3, TRL-C, non-HDL-C, apoB, and MDA-LDL levels as risk factors for NA. However, when apoB was included as a covariate, other factors became nonsignificant. CONCLUSIONS: Abnormal triglyceride-rich lipoprotein metabolism and high atherogenic apoB-containing lipoprotein particle numbers are associated with the formation of NA in patients undergoing statin treatment at a median 12 months post-PCI.

Fingolimod Does Not Reduce Infarction After Focal Cerebral Ischemia in Mice During Active or Inactive Circadian Phases.

BACKGROUND: It has been reported that the S1P (sphingosine 1-phosphate) receptor modulator fingolimod reduces infarction in rodent models of stroke. Recent studies have suggested that circadian rhythms affect stroke and neuroprotection. Therefore, this study revisited the use of fingolimod in mouse focal cerebral ischemia to test the hypothesis that efficacy might depend on whether experiments were performed during the inactive sleep or active wake phases of the circadian cycle. METHODS: Two different stroke models were implemented in male C57Bl/6 mice-transient middle cerebral artery occlusion and permanent distal middle cerebral artery occlusion. Occlusion occurred either during inactive or active circadian phases. Mice were treated with 1 mg/kg fingolimod at 30- or 60-minute postocclusion and 1 day later for permanent and transient middle cerebral artery occlusion, respectively. Infarct volume, brain swelling, hemorrhagic transformation, and behavioral outcome were assessed at 2 or 3 days poststroke. Three independent experiments were performed in 2 different laboratories. RESULTS: Fingolimod decreased peripheral lymphocyte number in naive mice, as expected. However, it did not significantly affect infarct volume, brain swelling, hemorrhagic transformation, or behavioral outcome at 2 or 3 days after transient or permanent focal cerebral ischemia during inactive or active circadian phases of stroke onset. CONCLUSIONS: Outcomes were not improved by fingolimod in either transient or permanent focal cerebral ischemia during both active and inactive circadian phases. These negative findings suggest that further testing of fingolimod in clinical trials may not be warranted unless translational studies can identify factors associated with fingolimod's efficacy or lack thereof.

Clinical features and lipid profiles of plaque erosion over lipid-rich plaque versus fibrous plaque in patients with acute coronary syndrome.

BACKGROUND AND AIMS: Pathological reports have shown that plaque erosion (PE), a common cause of acute coronary syndrome (ACS), can form in both fibrous plaque and lipid-rich plaque (LRP). In plaque rupture (PR), which is the main cause of ACS, the underlying plaque is LRP with a thin fibrous cap. In this study, we aimed to investigate the clinical features and lipid profiles of PE with or without LRP in comparison with those of PR. METHODS: A total of 166 patients with ACS, who underwent percutaneous coronary intervention using optical coherence tomography (OCT) and met the criteria for PR or PE, were included. LRP was defined as plaque with a maximal lipid arc (>180°). Culprit lesions were categorized into PR and PE with/without LRP [PE(Lipid) or PE(Fibrous)]. RESULTS: The prevalence of PR, PE(Lipid), and PE(Fibrous) was 104 (62.7%), 43 (25.9%), and 19(11.4%), respectively. The patients with PR and PE(Lipid) had a significantly higher peak creatine kinase level (1338 and 1584U/L, respectively, p < 0.01) and prevalence of ST-elevation myocardial infarction (71.2% and 79.1%, respectively, p < 0.01) than those with PE(Fibrous) (214U/L and 21.1%, respectively). The various lipid profiles were mostly comparable between the patients with PE(Lipid) and PR, but different in those with PE(Fibrous). The levels of small dense low-density lipoprotein cholesterol were significantly higher in the patients with PR and PE(Lipid) than in those with PE(Fibrous) (39.0, 35.3, and 25.7 mg/dL, respectively, p = 0.02). CONCLUSIONS: The clinical features and lipid profiles are substantially different between PE(Lipid) and PE(Fibrous), but are somewhat similar between PE(Lipid) and PR.