Inhibitory effects of naringenin on estrogen deficiency-induced obesity via regulation of mitochondrial dynamics and AMPK activation associated with white adipose tissue browning.

AIMS: Post-ovariectomy (OVX) changes in hormones induce obesity and white adipose tissue (WAT) inflammation. Increased energy expenditure via WAT browning is a novel therapeutic strategy for treating obesity. Naringenin (NAR) reduces inflammation and lipogenesis in obesity and attenuates estrogen deficiency-associated metabolic disorders; however, its role in WAT browning remains unclear. MATERIALS AND METHODS: We investigated NAR ability to inhibit estrogen deficiency-associated obesity in vivo using a rat model and in vitro using 3T3-L1 adipocytes. KEY FINDINGS: NAR significantly decreased the body weight and WAT mass of rats. O2 consumption, CO2 production, and energy expenditure were significantly lower in the OVX group than in the sham group, but NAR treatment reversed these effects of OVX. NAR treatment markedly improved glucose intolerance and lipid profiles as well as leptin, adiponectin, and irisin levels. NAR upregulated markers of browning and mitochondrial biogenesis in inguinal WAT. Moreover, it enhanced markers of mitochondrial fusion and inhibited fission via activating the AMP-activated protein kinase pathway. Similar results were observed in 3T3-L1 adipocytes. Moreover, NAR-induced mitochondrial biogenesis and fusion were suppressed by dorsomorphin (an AMP-activated protein kinase inhibitor). SIGNIFICANCE: NAR alleviates obesity and metabolic dysfunction through the induction of WAT browning achieved via the modulation of AMP-activated protein kinase-regulated mitochondrial dynamics in WATs. NAR supplementation may therefore represent a potential intervention for preventing postmenopausal adipose tissue dysregulation.

PGC-1α-mediated angiogenesis prevents pulmonary hypertension in mice.

Pulmonary hypertension (PH) is a life-threatening disease characterized by a progressive narrowing of pulmonary arterioles. Although VEGF is highly expressed in lung of patients with PH and in animal PH models, the involvement of angiogenesis remains elusive. To clarify the pathophysiological function of angiogenesis in PH, we compared the angiogenic response in hypoxia (Hx) and SU5416 (a VEGFR2 inhibitor) plus Hx (SuHx) mouse PH models using 3D imaging. The 3D imaging analysis revealed an angiogenic response in the lung of the Hx-PH, but not of the severer SuHx-PH model. Selective VEGFR2 inhibition with cabozantinib plus Hx in mice also suppressed angiogenic response and exacerbated Hx-PH to the same extent as SuHx. Expression of endothelial proliferator-activated receptor γ coactivator 1α (PGC-1α) increased along with angiogenesis in lung of Hx-PH but not SuHx mice. In pulmonary endothelial cell-specific Ppargc1a-KO mice, the Hx-induced angiogenesis was suppressed, and PH was exacerbated along with increased oxidative stress, cellular senescence, and DNA damage. By contrast, treatment with baicalin, a flavonoid enhancing PGC-1α activity in endothelial cells, ameliorated Hx-PH with increased Vegfa expression and angiogenesis. Pulmonary endothelial PGC-1α-mediated angiogenesis is essential for adaptive responses to Hx and might represent a potential therapeutic target for PH.

Paving the Way for Memory Enhancement: Development and Examination of a Neurofeedback System Targeting the Medial Temporal Lobe.

Neurofeedback (NF) shows promise in enhancing memory, but its application to the medial temporal lobe (MTL) still needs to be studied. Therefore, we aimed to develop an NF system for the memory function of the MTL and examine neural activity changes and memory task score changes through NF training. We created a memory NF system using intracranial electrodes to acquire and visualise the neural activity of the MTL during memory encoding. Twenty trials of a tug-of-war game per session were employed for NF and designed to control neural activity bidirectionally (Up/Down condition). NF training was conducted with three patients with drug-resistant epilepsy, and we observed an increasing difference in NF signal between conditions (Up-Down) as NF training progressed. Similarities and negative correlation tendencies between the transition of neural activity and the transition of memory function were also observed. Our findings demonstrate NF's potential to modulate MTL activity and memory encoding. Future research needs further improvements to the NF system to validate its effects on memory functions. Nonetheless, this study represents a crucial step in understanding NF's application to memory and provides valuable insights into developing more efficient memory enhancement strategies.

Intracranial Neurofeedback Modulating Neural Activity in the Mesial Temporal Lobe During Memory Encoding: A Pilot Study.

Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seizure freedom in patients with intractable MTL epilepsy; however, it carries the potential risk of memory damage. Neurofeedback (NF), which regulates brain function by converting brain activity into perceptible information and providing feedback, has attracted considerable attention in recent years for its potential as a novel complementary treatment for many neurological disorders. However, no research has attempted to artificially reorganize memory functions by applying NF before resective surgery to preserve memory functions. Thus, this study aimed (1) to construct a memory NF system that used intracranial electrodes to feedback neural activity on the language-dominant side of the MTL during memory encoding and (2) to verify whether neural activity and memory function in the MTL change with NF training. Two intractable epilepsy patients with implanted intracranial electrodes underwent at least five sessions of memory NF training to increase the theta power in the MTL. There was an increase in theta power and a decrease in fast beta and gamma powers in one of the patients in the late stage of memory NF sessions. NF signals were not correlated with memory function. Despite its limitations as a pilot study, to our best knowledge, this study is the first to report that intracranial NF may modulate neural activity in the MTL, which is involved in memory encoding. The findings provide important insights into the future development of NF systems for the artificial reorganization of memory functions.

Perivascular adipose tissue in vascular pathologies-a novel therapeutic target for atherosclerotic disease?

Most blood vessels are surrounded by adipose tissues known as perivascular adipose tissue (PVAT). Emerging experimental data have implicated the potential involvement of PVAT in the pathogenesis of cardiovascular disease: PVAT might be a source of inflammatory mediators under pathological conditions such as metabolic disorders, chronic inflammation, and aging, leading to vascular pathologies, while having vasculo-protective roles in a healthy state. PVAT has been also gaining attention in human disease conditions. Recent integrative omics approaches have greatly enhanced our understanding of the molecular mechanisms underlying the diverse functions of PVAT. This review summarizes recent progress in PVAT research and discusses the potential of PVAT as a target for the treatment of atherosclerosis.

The emerging role of estrogen's non-nuclear signaling in the cardiovascular disease.

Sexual dimorphism exists in the epidemiology of cardiovascular disease (CVD), which indicates the involvement of sexual hormones in the pathophysiology of CVD. In particular, ample evidence has demonstrated estrogen's protective effect on the cardiovascular system. While estrogen receptors, bound to estrogen, act as a transcription factor which regulates gene expressions by binding to the specific DNA sequence, a subpopulation of estrogen receptors localized at the plasma membrane induces activation of intracellular signaling, called "non-nuclear signaling" or "membrane-initiated steroid signaling of estrogen". Although the precise molecular mechanism of non-nuclear signaling as well as its physiological impact was unclear for a long time, recent development of genetically modified animal models and pathway-selective estrogen receptor stimulant bring new insights into this pathway. We review the published experimental studies on non-nuclear signaling of estrogen, and summarize its role in cardiovascular system, especially focusing on: (1) the molecular mechanism of non-nuclear signaling; (2) the design of genetically modified animals and pathway-selective stimulant of estrogen receptor.

Novel AGL variants in a patient with glycogen storage disease type IIIb and pulmonary hypertension caused by pulmonary veno-occlusive disease: A case report.

Glycogen storage disease type III (GSD-III) is an autosomal recessive metabolic disorder caused by mutations in the AGL gene, and may develop various types of pulmonary hypertension (PH). Here, we report a case of 24-year-old man with GSD-IIIb with two novel null variants in AGL (c.2308 + 2T>C and c.3045_3048dupTACC). He developed multi-drug-resistant pulmonary veno-occlusive disease (PVOD) and was registered as a candidate for lung transplantation. No pathogenic variants were detected in previously known causative genes for pulmonary hypertension and the underlying mechanism of coincidence of two rare diseases was unknown. We discuss the association of the loss of glycogen-debranching enzyme with incident PVOD.

Tie2-Cre-Induced Inactivation of Non-Nuclear Estrogen Receptor-α Signaling Abrogates Estrogen Protection Against Vascular Injury.

Using the Cre-loxP system, we generated the first mouse model in which estrogen receptor-α non-nuclear signaling was inactivated in endothelial cells. Estrogen protection against mechanical vascular injury was impaired in this model. This result indicates the pivotal role of endothelial estrogen receptor-α non-nuclear signaling in the vasculoprotective effects of estrogen.

Effects of inhaling essential oils of Citrus limonum L., Santalum album, and Cinnamomum camphora on human brain activity.

INTRODUCTION: Essential oil inhalation has various effects on the human body. However, its effects on cognitive function and the neural basis remain unclear. We aimed to investigate the effects of inhaling lemon, sandalwood, and kusunoki essential oils on human brain activity and memory function using multichannel electroencephalography and brain source activity estimation. METHODS: Participants performed a letter 2-back working memory task during electroencephalography measurements before and after essential oil inhalation. Brain activation, task difficulty, concentration degree, and task performance were compared among the essential oils and a fragrance-free control. RESULTS: Task performance significantly improved after lemon essential oil inhalation. Lemon essential oil inhalation resulted in delta and theta band activation in the prefrontal cortex, including the anterior cingulate gyrus and orbitofrontal cortex, superior temporal gyrus, parahippocampal gyrus, and insula. During inhalation, persistent alpha band activation was observed in the prefrontal cortex, including the anterior cingulate gyrus. Sandalwood essential oil inhalation led to beta and gamma band activation in the prefrontal cortex, including the anterior cingulate gyrus. CONCLUSION: Our findings demonstrate that different essential oils have specific effects on brain activity related to emotion and memory processing.

Free energy model of emotional valence in dual-process perceptions.

An appropriate level of arousal induces positive emotions, and a high arousal potential may provoke negative emotions. To explain the effect of arousal on emotional valence, we propose a novel mathematical framework of arousal potential variations in the dual process of human cognition: automatic and controlled. A suitable mathematical formulation to explain the emotions in the dual process is still absent. Our model associates free energy with arousal potential and its variations to explain emotional valence. Decreasing and increasing free energy consequently induce positive and negative emotions, respectively. We formalize a transition from the automatic to the controlled process in the dual process as a change of Bayesian prior. Further, we model emotional valence using free energy increase (FI) when one tries changing one's Bayesian prior and its reduction (FR) when one succeeds in recognizing the same stimuli with a changed prior and define three emotions: "interest," "confusion," and "boredom" using the variations. The results of our mathematical analysis comparing various Gaussian model parameters reveals the following: (1) prediction error (PR) increases FR (representing "interest") when the first prior variance is greater than the second prior variance, (2) PR decreases FR when the first prior variance is less than the second prior variance, and (3) the distance between priors' means always increases FR. We also discuss the association of the outcomes with emotions in the controlled process. The proposed mathematical model provides a general framework for predicting and controlling emotional valence in the dual process that varies with viewpoint and stimuli, as well as for understanding the contradictions in the effects of arousal on the valence.

Vertebral osteomyelitis secondary to infective endocarditis detected by repeated magnetic resonance imaging: a case report.

Background: Patients with infective endocarditis (IE) experience various symptoms, a major one being back pain, which is occasionally caused by concomitant vertebral osteomyelitis (VO). Magnetic resonance imaging (MRI) is generally used to detect VO; however, the sensitivity of detection using MRI is very low in the early stages of VO. Case summary: A 60-year-old man visited our hospital with complaints of fever and persistent back pain over the past 7 days. A holosystolic heart murmur was auscultated, and an echocardiography revealed a vegetation on the posterior mitral leaflet. Blood cultures were positive for Streptococcus sanguinis. He was diagnosed with IE and treated with antimicrobials. A lumbar spine MRI on Day 1 showed no clear signs of vertebral infection, but the back pain continued and gradually worsened. Magnetic resonance imaging retest on Day 8 showed high signal intensity within the lumbar vertebral bodies and the disk on T2-weighted sequences, indicating VO. Intravenous antimicrobial therapy was extended, followed by oral antimicrobials, and a corset was put on to protect the lumbar spine to prevent bone degradation. Discussion: For persistent back pain in IE patients, repeat MRIs at regular intervals of time can detect possible vertebral infection even if signs of vertebral infection were absent on the initial MRI.

Beiging of perivascular adipose tissue regulates its inflammation and vascular remodeling.

Although inflammation plays critical roles in the development of atherosclerosis, its regulatory mechanisms remain incompletely understood. Perivascular adipose tissue (PVAT) has been reported to undergo inflammatory changes in response to vascular injury. Here, we show that vascular injury induces the beiging (brown adipose tissue-like phenotype change) of PVAT, which fine-tunes inflammatory response and thus vascular remodeling as a protective mechanism. In a mouse model of endovascular injury, macrophages accumulate in PVAT, causing beiging phenotype change. Inhibition of PVAT beiging by genetically silencing PRDM16, a key regulator to beiging, exacerbates inflammation and vascular remodeling following injury. Conversely, activation of PVAT beiging attenuates inflammation and pathological vascular remodeling. Single-cell RNA sequencing reveals that beige adipocytes abundantly express neuregulin 4 (Nrg4) which critically regulate alternative macrophage activation. Importantly, significant beiging is observed in the diseased aortic PVAT in patients with acute aortic dissection. Taken together, vascular injury induces the beiging of adjacent PVAT with macrophage accumulation, where NRG4 secreted from the beige PVAT facilitates alternative activation of macrophages, leading to the resolution of vascular inflammation. Our study demonstrates the pivotal roles of PVAT in vascular inflammation and remodeling and will open a new avenue for treating atherosclerosis.

A pacing-controlled protocol for frequency-diastolic relations distinguishes diastolic dysfunction specific to a mouse HFpEF model.

Heart failure with preserved ejection fraction (HFpEF), characterized by diastolic dysfunction and insufficient exercise capacity, is a growing health problem worldwide. One major difficulty with experimental research on HFpEF is the lack of methods to consistently detect diastolic dysfunction in mouse models. We developed a pacing-controlled pressure-volume (PV) loop protocol for the assessment of diastolic function at different heart rates in mice and tested if the protocol could detect diastolic dysfunction specific to a HFpEF model. A HFpEF model was generated by high-fat diet (HFD) feeding with concomitant NG-nitro-l-arginine methyl ester administration, and a pressure-overload hypertrophy (PO) model was produced by surgical constriction of the transverse aorta (TAC). Heart rate (HR) was slowed below 400 beats/min by intraperitoneal injection of ivabradine. PV loop data were acquired and analyzed at HR incrementing from 400 to 700 beats/min via atrial pacing using a miniature pacing catheter inserted into the esophagus, and comparisons were made among control, HFpEF, and PO mice. At baseline without pacing, no diastolic abnormalities were detected in either PO or HFpEF models. Frequency-diastolic relations, however, revealed the significant diastolic impairment specific to the HFpEF model; both relaxation time constant (Tau) and end-diastolic pressure-volume relationship (EDPVR) were worsened as heart rate increased. Peak positive first derivative of left ventricular pressure (dP/dtmax) was significantly lower in HFpEF versus controls only at a high HR of 700 beats/min. A pacing-controlled protocol would be a feasible and potent method to detect diastolic dysfunction specific to a mouse HFpEF model.NEW & NOTEWORTHY We developed a pacing-controlled PV loop protocol for the assessment of diastolic function at different heart rates in mice, which is a feasible and potent method for the characterization of diastolic dysfunction in a murine HFpEF model whose diastolic dysfunction might be difficult to be detected under resting conditions without pacing.

An Unusual Case of Left Ventricular Outflow Tract Obstruction after Aortic Valve Replacement.

Surgical valve replacement improves the symptoms and prognosis of patients with valvular heart diseases. Aortic regurgitation elicits volume overload that causes enlargement of the left ventricle (LV), while the LV size often shrinks to near normal after aortic valve replacement (AVR), which is referred to as "reverse remodeling". We experienced a case in which LV outflow tract (LVOT) obstruction became apparent after AVR, resulting in worsening of heart failure. A 65-year-old man who had undergone surgical AVR for aortic valve regurgitation 15 months previously exhibited dyspnea on effort accompanied with severe LVOT obstruction. With double pressure catheters, we directly recorded an augmented pressure gradient in the LVOT and rapid relief of the obstruction by intravenous administration of the anti-arrhythmic drug cibenzoline. Since the considerable LV hypertrophy had been indicated by an electrocardiogram and echocardiography before AVR, we suspected that dilation of the LV chamber due to aortic valve regurgitation could have masked the subclinical LVOT obstruction, which became clinically evident after LV size reduction due to reverse remodeling after AVR.

The mitochondrial regulator PGC1α is induced by cGMP-PKG signaling and mediates the protective effects of phosphodiesterase 5 inhibition in heart failure.

Phosphodiesterase 5 inhibition (PDE5i) activates cGMP-dependent protein kinase (PKG) and ameliorates heart failure; however, its impact on cardiac mitochondrial regulation has not been fully determined. Here, we investigated the role of the mitochondrial regulator peroxisome proliferator-activated receptor γ co-activator-1α (PGC1α) in the PDE5i-conferred cardioprotection, utilizing PGC1α null mice. In PGC1α+/+ hearts exposed to 7 weeks of pressure overload by transverse aortic constriction, chronic treatment with the PDE5 inhibitor sildenafil improved cardiac function and remodeling, with improved mitochondrial respiration and upregulation of PGC1α mRNA in the myocardium. By contrast, PDE5i-elicited benefits were abrogated in PGC1α-/- hearts. In cultured cardiomyocytes, PKG overexpression induced PGC1α, while inhibition of the transcription factor CREB abrogated the PGC1α induction. Together, these results suggest that the PKG-PGC1α axis plays a pivotal role in the therapeutic efficacy of PDE5i in heart failure.

Sex Differences and Regulatory Actions of Estrogen in Cardiovascular System.

Great progress has been made in the understanding of the pathophysiology of cardiovascular diseases (CVDs), and this has improved the prevention and prognosis of CVDs. However, while sex differences in CVDs have been well documented and studied for decades, their full extent remains unclear. Results of the latest clinical studies provide strong evidence of sex differences in the efficacy of drug treatment for heart failure, thereby possibly providing new mechanistic insights into sex differences in CVDs. In this review, we discuss the significance of sex differences, as rediscovered by recent studies, in the pathogenesis of CVDs. First, we provide an overview of the results of clinical trials to date regarding sex differences and hormone replacement therapy. Then, we discuss the role of sex differences in the maintenance and disruption of cardiovascular tissue homeostasis.

How predictability affects habituation to novelty.

One becomes accustomed to repeated exposures, even for a novel event. In the present study, we investigated how predictability affects habituation to novelty by applying a mathematical model of arousal that we previously developed, and through the use of psychophysiological experiments to test the model's prediction. We formalized habituation to novelty as a decrement in Kullback-Leibler divergence from Bayesian prior to posterior (i.e., information gain) representing arousal evoked from a novel event through Bayesian update. The model predicted an interaction effect between initial uncertainty and initial prediction error (i.e., predictability) on habituation to novelty: the greater the initial uncertainty, the faster the decrease in information gain (i.e., the sooner habituation occurs). This prediction was supported by experimental results using subjective reports of surprise and event-related potential (P300) evoked by visual-auditory incongruity. Our findings suggest that in highly uncertain situations, repeated exposure to stimuli can enhance habituation to novel stimuli.

Factors associated with left ventricular reverse remodelling after percutaneous coronary intervention in patients with left ventricular systolic dysfunction.

Percutaneous coronary intervention (PCI) is sometimes considered as an alternative therapeutic strategy to surgical revascularization in patients with coronary artery disease (CAD) and reduced left ventricular ejection fraction (LVEF). However, the types or conditions of patients that receive the clinical benefit of left ventricular reverse remodelling (LVRR) remain unknown. The purpose of this study was to investigate the determinants of LVRR following PCI in CAD patients with reduced LVEF. From 4394 consecutive patients who underwent PCI, a total of 286 patients with reduced LV systolic function (LVEF < 50% at initial left ventriculography) were included in the analysis. LVRR was defined as LV end-systolic volume reduction ≥ 15% and improvement of LVEF ≥ 10% at 6 months follow-up left ventriculography. Patients were divided into LVRR (n = 63) and non-LVRR (n = 223) groups. Multivariate logistic regression analysis revealed that unprotected left main coronary artery (LMCA) intervention was significantly associated with LVRR (P = 0.007, odds ratios [OR] 4.70, 95% confidence interval [CI] 1.54-14.38), while prior PCI (P = 0.001, OR 0.35, 95% CI 0.19-0.66), presence of in-stent restenosis (P = 0.016, OR 0.32, 95% CI 0.12-0.81), and presence of de-novo stenosis (P = 0.038, OR 0.36, 95% CI 0.14-0.95) were negatively associated with LVRR. These data suggest the potential prognostic benefit of unprotected LMCA intervention for LVRR and importance of angiographic follow-up in patients with CAD and LV systolic dysfunction.

Effects of Transcranial Direct Current Stimulation on Brain Networks Related to Creative Thinking.

Human creative thinking is unique and capable of generating novel and valuable ideas. Recent research has clarified the contribution of different brain networks (default mode network, DN; executive control network; salience network) to creative thinking. However, the effects of brain stimulation on brain networks during creative thinking and on creative performance have not been clarified. The present study was designed to examine the changes in functional connectivity (FC) and effective connectivity (EC) of the large-scale brain network, and the ensuing changes in creative performance, induced by transcranial direct current stimulation (tDCS). Fourteen healthy male students underwent two tDCS sessions, one with actual stimulation and one with sham stimulation, on two separate days. Participants underwent tDCS (anode over the left dorsolateral prefrontal cortex, DLPFC; cathode over the right inferior parietal lobule, IPL) for 20 min. Before and after the tDCS session, electroencephalography signals were acquired from 32 electrodes over the whole head during the creative thinking task. On FC analysis, the delta band FC between the posterior cingulate cortex and IPL significantly increased only after real stimulation. We also found that the change of flexibility score was significantly correlated with the change in: (i) delta band FC between mPFC and left lateral temporal cortex (LTC) and (ii) alpha band FC between IPL and right LTC. On EC analysis, decreased flow within the DN (from left LTC to right IPL) was observed. Our results reveal that tDCS could affect brain networks, particularly the DN, during creative thinking and modulate key FC in the generation of flexible creative ideas.