Yogurt Supplementation Attenuates Insulin Resistance in Obese Mice by Reducing Metabolic Endotoxemia and Inflammation.

BACKGROUND: Inflammation is an underlying mechanism for the development of obesity-related health complications. Yogurt consumption inhibits obesity-associated inflammation, but the tissue-specific mechanisms have not been adequately described. OBJECTIVES: We aimed to determine the tissue-specific responses by which yogurt supplementation inhibits inflammation. METHODS: C57BL/6 male mice (5 wk old) were fed a Teklad Global 14% Protein Rodent Maintenance diet as a control or a high-fat diet (60% calories from fat) to induce obesity for 11 wk, followed by feeding a Western diet (WD; 43% carbohydrate and 42% fat) or WD supplemented with 5.6% lyophilized yogurt powder for 3 wk to test for the impact of yogurt supplementation. Markers of metabolic endotoxemia and inflammation were assessed in plasma and tissues. Cecal and fecal microbiota were profiled by 16S rRNA sequencing. RESULTS: In obese mice, relative to the WD control group, yogurt supplementation attenuated HOMA-IR by 57% (P = 0.020), plasma TNF-α by 31% (P < 0.05) and colonic IFN-γ by 46% (P = 0.0034), which were accompanied by a 40% reduction in plasma LPS binding protein (LBP) (P = 0.0019) and 45% less colonic Lbp expression (P = 0.037), as well as alteration in the beta diversity of cecal microbiota (P = 0.0090) and relative abundance of certain cecal microbes (e.g., Lachnospiraceae Dorea longicatena with P = 0.049). There were no differences in the LBP, Lbp, and Cd14 levels in the liver and small intestine between obese mice with and without yogurt supplementation (P > 0.05). CONCLUSIONS: Yogurt consumption inhibits obesity-induced inflammation in mice by modulating colonic endotoxin detoxification, changing the gut microbiota, and improving glucose metabolism. This work helps to establish the underlying mechanisms by which yogurt consumption affects markers of metabolic and immune health.

Pretreatment with Clodronate Improved Neurological Function by Preventing Reduction of Posthemorrhagic Cerebral Blood Flow in Experimental Subarachnoid Hemorrhage.

BACKGROUND: Brain perivascular macrophages (PVMs) are potential treatment targets for subarachnoid hemorrhage (SAH), and previous studies revealed that their depletion by clodronate (CLD) improved outcomes after experimental SAH. However, the underlying mechanisms are not well understood. Therefore, we investigated whether reducing PVMs by CLD pretreatment improves SAH prognosis by inhibiting posthemorrhagic impairment of cerebral blood flow (CBF). METHODS: In total, 80 male Sprague-Dawley rats received an intracerebroventricular injection of the vehicle (liposomes) or CLD. Subsequently, the rats were categorized into the prechiasmatic saline injection (sham) and blood injection (SAH) groups after 72 h. We assessed its effects on weak and severe SAH, which were induced by 200- and 300-µL arterial blood injections, respectively. In addition, neurological function at 72 h and CBF changes from before the intervention to 5 min after were assessed in rats after sham/SAH induction as the primary and secondary end points, respectively. RESULTS: CLD significantly reduced PVMs before SAH induction. Although pretreatment with CLD in the weak SAH group provided no additive effects on the primary end point, rats in the severe SAH group showed significant improvement in the rotarod test. In the severe SAH group, CLD inhibited acute reduction of CBF and tended to decrease hypoxia-inducible factor 1α expression. Furthermore, CLD reduced the number of PVMs in rats subjected to sham and SAH surgery, although no effects were observed in oxidative stress and inflammation. CONCLUSIONS: Our study proposes that pretreatment with CLD-targeting PVMs can improve the prognosis of severe SAH through a candidate mechanism of inhibition of posthemorrhagic CBF reduction.

Central sympathetic nerve activation in subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a life-threatening condition, and although its two main complications-cerebral vasospasm (CVS)/delayed cerebral ischemia (DCI) and early brain injury (EBI)-have been widely studied, prognosis has not improved over time. The sympathetic nerve (SN) system is important for the regulation of cardiovascular function and is closely associated with cerebral vessels and the regulation of cerebral blood flow and cerebrovascular function; thus, excessive SN activation leads to a rapid breakdown of homeostasis in the brain. In the hyperacute phase, patients with SAH can experience possibly lethal conditions that are thought to be associated with SN activation (catecholamine surge)-related arrhythmia, neurogenic pulmonary edema, and irreversible injury to the hypothalamus and brainstem. Although the role of the SN system in SAH has long been investigated and considerable evidence has been collected, the exact pathophysiology remains undetermined, mainly because the relationships between the SN system and SAH are complicated, and many SN-modulating factors are involved. Thus, research concerning these relationships needs to explore novel findings that correlate with the relevant concepts based on past reliable evidence. Here, we explore the role of the central SN (CSN) system in SAH pathophysiology and provide a comprehensive review of the functional CSN network; brain injury in hyperacute phase involving the CSN system; pathophysiological overlap between the CSN system and the two major SAH complications, CVS/DCI and EBI; CSN-modulating factors; and SAH-related extracerebral organ injury. Further studies are warranted to determine the specific roles of the CSN system in the brain injuries associated with SAH.

Enhanced oxidative stress contributes to worse prognosis and delayed neurofunctional recovery after striatal intracerebral hemorrhage in 5XFAD mice.

Although Alzheimer's disease (AD) is associated with an increased risk of intracerebral hemorrhage (ICH) caused by hypertension and cerebral amyloid angiopathy, the precise clinical course after hypertensive ICH in AD patients is still unknown. In this study, we investigated how striatal ICH, a frequent site for hypertensive ICH, affected the prognosis of AD. We employed 17- and 18-month-old male 5XFAD (5X) mice and littermate (LT) controls, and striatal ICH was induced by collagenase injection. First, to address the acute effects of ICH on 5X mice, hemorrhagic volume and brain edema were evaluated 3 days after ICH. Next, to address the long-term effects of ICH on 5X mice, morbidity, mortality, neurological function (beam-walking and rotarod tests), and cognitive function (Y-maze and nest-building tests) were monitored. Twenty-eight days later, the animals were euthanized, their brains were isolated, and the cytotoxic alterations were investigated. The results revealed that the acute effects of ICH were not significantly different between 5X and LT mice. In contrast, 5X mice showed significantly higher morbidity and mortality in response to ICH, as well as delayed neurological function recovery, compared to LT mice through 28 days. ICH did not affect cognitive function in either group. Infiltrated macrophages in the perihemorrhagic cortex, gp91phox , p67phox , and COX-2 were significantly increased in 5X mice in response to ICH. We demonstrated that striatal ICH deteriorated prognosis and delayed neurofunctional recovery in 5X mice, which might be associated with enhanced oxidative stress in the presence of AD-like pathology.

Predictors for Functional Outcome in Patients with Aneurysmal Subarachnoid Hemorrhage Who Completed In-Hospital Rehabilitation in a Single Institution.

BACKGROUND: Although many studies evaluated independent prognosis factors of functional outcome in patients with subarachnoid hemorrhage (SAH) at a suitable time point, some patients take a long time to get functional improvement. The purpose of this study is to evaluate predictors for functional outcome in SAH patients who underwent surgical clipping and in-hospital rehabilitation in our single institution using Modified Rankin Scale (MRS) and Barthel Index (BI). METHODS: Two-hundred fifty-one SAH patients were admitted to our hospital from January 2008 to December 2017. Of them, 144 patients who diagnosed aneurysmal SAH, underwent surgical clipping within 72 hours, and completed subsequent in-hospital rehabilitation were included in this study. We explored their clinical variables and evaluated the relationships between those factors and functional outcome using MRS and BI. RESULTS: In multivariate analysis, independent prognostic factors of both MRS and BI were age, World Federation of Neurologic Surgeons grade, and symptomatic vasospasm. CONCLUSIONS: We suggest that age, SAH severity, and symptomatic vasospasm are associated with functional outcome in patients with aneurysmal SAH who completed surgical clipping and in-hospital rehabilitation.

Variability of Gene Expression Identifies Transcriptional Regulators of Early Human Embryonic Development.

An analysis of gene expression variability can provide an insightful window into how regulatory control is distributed across the transcriptome. In a single cell analysis, the inter-cellular variability of gene expression measures the consistency of transcript copy numbers observed between cells in the same population. Application of these ideas to the study of early human embryonic development may reveal important insights into the transcriptional programs controlling this process, based on which components are most tightly regulated. Using a published single cell RNA-seq data set of human embryos collected at four-cell, eight-cell, morula and blastocyst stages, we identified genes with the most stable, invariant expression across all four developmental stages. Stably-expressed genes were found to be enriched for those sharing indispensable features, including essentiality, haploinsufficiency, and ubiquitous expression. The stable genes were less likely to be associated with loss-of-function variant genes or human recessive disease genes affected by a DNA copy number variant deletion, suggesting that stable genes have a functional impact on the regulation of some of the basic cellular processes. Genes with low expression variability at early stages of development are involved in regulation of DNA methylation, responses to hypoxia and telomerase activity, whereas by the blastocyst stage, low-variability genes are enriched for metabolic processes as well as telomerase signaling. Based on changes in expression variability, we identified a putative set of gene expression markers of morulae and blastocyst stages. Experimental validation of a blastocyst-expressed variability marker demonstrated that HDDC2 plays a role in the maintenance of pluripotency in human ES and iPS cells. Collectively our analyses identified new regulators involved in human embryonic development that would have otherwise been missed using methods that focus on assessment of the average expression levels; in doing so, we highlight the value of studying expression variability for single cell RNA-seq data.

Renal Denervation in the Acute Phase of Ischemic Stroke Provides Brain Protection in Hypertensive Rats.

BACKGROUND AND PURPOSE: Renal denervation (RD) may protect against cardiovascular diseases regardless of blood pressure (BP)-lowering effect. We hypothesized that RD can improve the outcome of acute ischemic stroke (AIS) in hypertensive rats. METHODS: An AIS model of spontaneously hypertensive stroke-prone rats (SHRSPs) was prepared by 90-minute middle cerebral artery occlusion followed by reperfusion. At 30 minutes poststroke, the SHRSPs were subjected to (1) sham operation or (2) RD to determine the beneficial effects of RD posttreatment. In addition, we evaluated the neuroprotective effects of RD posttreatment in Wistar Kyoto rats and RD pretreatment in SHRSPs with AIS. RESULTS: RD significantly ameliorated neurological deficit and infarct volume at 1 and 7 days after middle cerebral artery occlusion. RD immediately and continuously normalized elevated BP during 24 hours. This normalization of BP by RD was associated with the reduction of cerebral blood flow during both middle cerebral artery occlusion and reperfusion periods. Thus, RD-induced BP normalization seems to ameliorate cerebrovascular overperfusion in SHRSPs with AIS. On the contrary, RD did not affect cerebral vascular resistance or cerebral vasoreactivity and did not increase Akt and endothelial NO synthase phosphorylation, thereby indicating no apparent change of cerebrovascular function. RD significantly attenuated cerebral oxidative stress as estimated by dihydroethidium staining and gp91phox expression. The beneficial effects were not seen in Wistar Kyoto rats, whereas RD pretreatment improved neurological function in SHRSPs. CONCLUSIONS: RD posttreatment improved outcome in the hypertensive AIS rat model. Therefore, we suggest that BP normalization by RD may be a promising therapeutic strategy for AIS.

Ion-sensitive photonic-crystal nanolaser sensors.

In general, biochemical sensors based on photonic cavities are used to detect changes in the refractive index of the environment. In this study, however, a GaInAsP semiconductor photonic-crystal nanolaser sensor that we recently developed was found to detect not only the environmental refractive index but also the surface charge. In contrast to the pH sensitivity we reported previously, this is an ultra-sensitive detection mechanism capable of identifying proteins and deoxyribonucleic acids (DNA) at a femtomolar-order or lower concentrations. When the device is exposed to plasma or DNA solutions, the laser wavelength simultaneously changes with the zeta potential and the flat-band potential of the semiconductor surface. This indicates that the charged functional groups on the surface, which are formed by these treatments, modify the Schottky barrier near the semiconductor surface, trap the excited carriers in the barrier, and change the refractive index of the semiconductor via the carrier effects. These findings also suggest that some other photonic sensors may also exhibit similar electrochemical and optoelectronic effects.

DPP-4 inhibition with linagliptin ameliorates the progression of premature aging in klotho-/- mice.

BACKGROUND: The potential of anti-aging effect of DPP-4 inhibitors is unknown. This study was performed to determine whether linagliptin, a DPP-4 inhibitor, could protect against premature aging in klotho-/- mice. METHODS: Klotho-/- mice exhibit multiple phenotypes resembling human premature aging, including extremely shortened life span, cognitive impairment, hippocampal neurodegeneration, hair loss, muscle atrophy, hypoglycemia, etc. To investigate the effect of linagliptin on these aging-related phenotypes, male klotho-/- mice were divided into two groups: (1) control group fed the standard diet, and (2) linagliptin group fed the standard diet containing linagliptin. Treatment with linagliptin was performed for 4 weeks. The effect of linagliptin on the above mentioned aging-related phenotypes was examined. RESULTS: Body weight of klotho-/- mice was greater in linagliptin group than in control group (11.1 ± 0.3 vs 9.9 ± 0.3 g; P < 0.01), which was associated with greater gastrocnemius muscle weight (P < 0.01) and greater kidney weight (P < 0.05) in linagliptin group. Thus, linagliptin significantly prevented body weight loss in klotho-/- mice. Survival rate of klotho-/- mice was greater in linagliptin group (93%) compared to control group (67%), although the difference did not reach statistical significance (P = 0.08). None of linagliptin-treated klotho-/- mice had alopecia during the treatment (P < 0.05 vs control klotho-/- mice). Latency of klotho-/- mice in passive avoidance test was larger in linagliptin group than in control group (P < 0.05), indicating the amelioration of cognitive impairment by linagliptin. Cerebral blood flow of klotho-/- mice was larger in linagliptin group than in control group (P < 0.01), being associated with greater cerebral phospho-eNOS levels (P < 0.05) in linagliptin group. Neuronal cell number in hippocampal CA1 region was greater in linagliptin group than in control group (P < 0.05). Linagliptin group had greater cerebral phospho-Akt (P < 0.05) and phospho-CREB (P < 0.05) than control group. Thus, linagliptin ameliorated brain aging in klotho-/- mice. The degree of hypoglycemia in klotho-/- mice was less in linagliptin group than in control group, as estimated by the findings of OGTT. CONCLUSIONS: Out work provided the evidence that DPP-4 inhibition with linagliptin slowed the progression of premature aging in klotho-/- mice, and provided a novel insight into the potential role of DPP-4 in the mechanism of premature aging.

Empagliflozin lessened cardiac injury and reduced visceral adipocyte hypertrophy in prediabetic rats with metabolic syndrome.

BACKGROUND: The potential benefit of SGLT2 inhibitors in metabolic syndrome is with prediabetic stage unclear. This work was undertaken to investigate the non-glycemic effect of empagliflozin on metabolic syndrome rats with prediabetes. METHODS: SHR/NDmcr-cp(+/+) rats (SHRcp), a model of metabolic syndrome with prediabetes, were given empagliflozin for 10 weeks to examine the effects on urinary sodium and water balance, visceral and subcutaneous adipocyte, and cardiac injury. Further, the effect of empagliflozin on blood pressure and autonomic nervous system was continuously investigated by using radiotelemetry system. RESULTS: Empagliflozin significantly reduced urinary sodium and water balance of SHRcp only within 1 week of the treatment, but later than 1 week did not alter them throughout the treatment. Empagliflozin significantly reduced body weight of SHRcp, which was mainly attributed to the significant reduction of subcutaneous fat mass. Empagliflozin significantly reduced the size of visceral adipocytes and increased the number of smaller size of adipocytes, which was associated with the attenuation of oxidative stress. Empagliflozin ameliorated cardiac hypertrophy and fibrosis of SHRcp, in association with the attenuation of cardiac oxidative stress and inflammation. However, empagliflozin did not significantly change blood pressure, heart rate, sympathetic activity, or baroreceptor function, as evidenced by radiotelemetry analysis. CONCLUSIONS: Our present work provided the evidence that SGLT2 inhibition reduced visceral adipocytes hypertrophy and ameliorated cardiac injury in prediabetic metabolic syndrome rat, independently of diuretic effect or blood pressure lowering effect. Thus, SGLT2 inhibition seems to be a promising therapeutic strategy for prediabetic metabolic syndrome.

Assessment of the Correlations Between Brain Weight and Brain Edema in Experimental Subarachnoid Hemorrhage.

Because brain edema is correlated with poor outcome in clinical subarachnoid hemorrhage (SAH), appropriate evaluation methods for brain edema are important in experimental SAH studies. Although brain water content (BWC) is widely used to evaluate brain edema in stroke research, the usefulness of brain weight is undetermined. In this study, we examined the role of brain weight in the evaluation of brain edema in experimental SAH. The endovascular perforation model of SAH was used, and rats were assessed by neurological scoring (NS). The brains were quickly removed at 24 h after the operation, and the weights of wet cerebrum (WWC) and dry cerebrum (WDC) were measured to determine the brain water content (BWC). The correlations of those values with each other and to body weight (BW) were then examined to reveal the significance of brain weight. The rats were assigned to sham-operated (n = 8) and SAH (n = 16) groups. There were no significant differences in WWC between the groups (p = 0.61). WWC was correlated with BWC but not with NS in all rats. In addition, WWC was clearly correlated with BW and WDC, which is thought to substitute for the original brain weight. From these results, we suggest that the measurement of brain weight as an evaluation of brain edema is limited and that BW and original brain volume can be confounding factors in evaluation.

Effects of Low-Dose Unfractionated Heparin Pretreatment on Early Brain Injury after Subarachnoid Hemorrhage in Mice.

Heparin is a pleiotropic drug that antagonizes many pathophysiological mechanisms. In this study, we evaluated whether heparin prevents early brain injury (EBI) after subarachnoid hemorrhage (SAH) in mice. SAH was induced by endovascular perforation in mice randomly assigned to sham-operated (n = 8), SAH + vehicle (n = 12), SAH + 10 U heparin pretreatment (n = 11), and SAH + 30 U heparin pretreatment (n = 14) groups. At 24 h post-SAH, severity of SAH, neurological scores, and brain water content were evaluated. Low-dose heparin pretreatment improved neurobehavioral function, and decreased brain edema in the ipsilateral cerebral hemisphere to the perforation side. High-dose heparin had a tendency for increased SAH, which obscured the neuroprotective effects by heparin. Low-dose heparin pretreatment may decrease the development of post-SAH EBI.

Transcatheter Arterial Embolization with Ethanol Injection in Symptomatic Patients with Enlarged Polycystic Kidneys.

PURPOSE: To evaluate the safety and effectiveness of transcatheter arterial embolization (TAE) with ethanol in symptomatic patients with enlarged polycystic kidney disease. MATERIALS AND METHODS: This prospective study was institutional review board approved and was planned for patients with symptoms related to enlarged polycystic kidney disease, such as a markedly distended abdomen, gastroesophageal reflux, and abdominal pain. At the time of TAE, all patients were undergoing dialysis therapy for chronic renal failure, and their urinary volume had decreased to less than 500 mL per day. Bilateral renal TAE with absolute ethanol was performed, and changes in kidney volume, clinical symptoms, laboratory data, and complications were evaluated after TAE. The differences in patients' kidney volumes, clinical symptoms, abdominal circumference, and dry weights before and after TAE were analyzed with a mixed effect model. RESULTS: Fifteen patients (seven men and eight women; mean age, 57.7 years ± 5.3 [standard deviation]) were treated. Among the 15 patients, the follow-up period was 24 months in 13 patients, 6 months in one patient, and 3 months in one patient. The mean kidney volume was 3380 mL before renal TAE, and at 3, 12, and 24 months after TAE, it significantly decreased to 60.9%, 39.8%, and 32.1% of the pretherapeutic value, respectively (P < .001). All patients reported improved clinical symptoms within 3 months after TAE (P < .001). Abdominal circumferences were significantly decreased after TAE (P < .001). The dry weights also continued to significantly decreased until 6 months after TAE (P < .001), at which point they began to slightly increase until 24 months after TAE. Abdominal pain, nausea, and inflammatory response developed in all patients after TAE, but these symptoms improved with conservative treatment. Abscess formation was found in one kidney, and drainage catheter placement was performed. No major complications related to TAE occurred in the remaining patients. CONCLUSION: Renal contraction therapy by TAE with ethanol injection appears to be a safe and effective treatment in patients with symptomatic enlarged polycystic kidney disease.

DPP-4 inhibition with linagliptin ameliorates cognitive impairment and brain atrophy induced by transient cerebral ischemia in type 2 diabetic mice.

BACKGROUND: It is unclear whether dipeptidylpeptidase-4 (DPP-4) inhibition can counteract the impairment of cognitive function and brain injury caused by transient cerebral ischemia in type 2 diabetes. The present study was undertaken to test our hypothesis that linagliptin, a DPP-4 inhibitor, administration following transient cerebral ischemia can ameliorate cognitive impairment and brain injury in diabetic mice. METHODS: db/db mice, a model of obese type 2 diabetes, were subjected to transient cerebral ischemia by 17 min of bilateral common carotid artery occlusion (BCCAO), and were administered (1) vehicle or (2) linagliptin for 8 weeks or 1 week. For the long-term experiment on 8 weeks of linagliptin treatment, cognitive function, and volume and neuronal cell number of hippocampus and cortex were estimated in each group of mice. For the short-term experiment on 1 week of linagliptin treatment, cerebral IgG extravasation, Iba-1 positive cell number (reactive microglia), oxidative stress, and claudin-5 and gp91phox protein levels were measured in each group of mice. RESULTS: Linagliptin administration almost completely suppressed the circulating DPP-4 activity in db/db mice, but did not significantly reduce blood glucose or ameliorate glucose intolerance in db/db mice. Linagliptin administration following transient cerebral ischemia significantly counteracted cognitive impairment in diabetic mice, as estimated by water maze test and passive avoidance test. Linagliptin administration ameliorated the decrease in cerebral volume and neuronal cell number in hippocampus and cortex of diabetic mice. Linagliptin administration significantly reduced the increase in cerebral IgG extravasation and the increase in reactive microglia caused by transient cerebral ischemia in diabetic mice. Furthermore, linagliptin significantly suppressed the increase in cerebral oxidative stress in transient cerebral ischemia-subjected diabetic mice. Furthermore, linagliptin significantly increased cerebral claudin-5 and significantly decreased gp91phox in diabetic mice subjected to transient cerebral ischemia. CONCLUSIONS: DPP-4 inhibition with linagliptin counteracted cognitive impairment and brain atrophy induced by transient cerebral ischemia in diabetic mice, independently of blood glucose lowering effect. This cerebroprotective effect of linagliptin was associated with the suppression of blood-brain barrier disruption and the attenuation of cerebral oxidative stress. Thus, our present work highlights DPP-4 inhibition as a promising therapeutic strategy for cognitive impairment and cerebral vascular complications in type 2 diabetes.

Apoptosis signal-regulating kinase 1 is a novel target molecule for cognitive impairment induced by chronic cerebral hypoperfusion.

OBJECTIVE: There are currently no specific strategies for the treatment or prevention of vascular dementia. White matter lesions, a common pathology in cerebral small vessel disease, are a major cause of vascular dementia. We investigated whether apoptosis signal-regulating kinase 1 (ASK1) might be a key molecule in cerebral hypoperfusion, associated with blood-brain barrier breakdown and white matter lesions. APPROACH AND RESULTS: A mouse model of cognitive impairment was developed by inducing chronic cerebral hypoperfusion in white matter including the corpus callosum via bilateral common carotid artery stenosis (BCAS) surgery. BCAS-induced white matter lesions caused cognitive decline in C57BL/6J (wild-type) mice but not in ASK1-deficient (ASK1(-/-)) mice. Phosphorylated ASK1 increased in wild-type mouse brains, and phosphorylated p38 and tumor necrosis factor-α expression increased in corpus callosum cerebral endothelial cells after BCAS in wild-type mice but not in ASK1(-/-) mice. BCAS decreased claudin-5 expression and disrupted blood-brain barrier in the corpus callosum of wild-type but not ASK1(-/-) mice. Cerebral nitrotyrosine was increased in wild-type and ASK1(-/-) BCAS mice. Cerebral phosphorylated ASK1 did not increase in wild-type mice treated with NADPH-oxidase inhibitor. A p38 inhibitor and NADPH-oxidase inhibitor mimicked the protective effect of ASK1 deficiency against cognitive impairment. Specific ASK1 inhibitor prevented cognitive decline in BCAS mice. In vitro oxygen-glucose deprivation and tumor necrosis factor-α stimulation caused the disruption of endothelial tight junctions from wild-type mice but not ASK1(-/-) mice. CONCLUSIONS: Oxidative stress-ASK1-p38 cascade plays a role in the pathogenesis of cognitive impairment, through blood-brain barrier breakdown via the disruption of endothelial tight junctions. ASK1 might be a promising therapeutic target for chronic cerebral hypoperfusion-induced cognitive impairment.

Isoflurane on brain inflammation.

Brain inflammation may play an important role in the pathophysiology of early brain injury after subarachnoid hemorrhage (SAH). Our aim was to demonstrate brain inflammation development and to determine whether isoflurane, a clinically available volatile anesthetic agent, prevents brain inflammation after SAH. This study used 162 8-week-old male CD-1 mice. We induced SAH with endovascular perforation in mice and randomly assigned animals to sham-operated (n=21), SAH+vehicle-air (n=35) and SAH+2% isoflurane (n=31). In addition to the evaluation of brain injury (neurological scores, brain edema and Evans blue dye extravasation), brain inflammation was evaluated by means of expression changes in markers of inflammatory cells (ionized calcium binding adaptor molecule-1, myeloperoxidase), cytokines (tumor necrosis factor [TNF]-α, interleukin-1ß), adhesion molecules (intercellular adhesion molecule [ICAM]-1, P-selectin), inducers of inflammation (cyclooxygenase-2, phosphorylated c-Jun N-terminal kinase [p-JNK]) and endothelial cell activation (von Willebrand factor) at 24h post-SAH. Sphingosine kinase inhibitor (N, N-dimethylsphingosine [DMS]) and sphingosine-1-phosphate receptor-1/3 antagonist (VPC23019) were used to block isoflurane's effects (n=22, each). SAH caused early brain injury, which was associated with inflammation so that all evaluated markers of inflammation were increased. Isoflurane significantly inhibited both brain injury (P<0.001, respectively) and inflammation (myeloperoxidase, P=0.022; interleukin-1ß, P=0.002; TNF-α, P=0.015; P-selectin, P=0.010; ICAM-1, P=0.016; p-JNK, P<0.001; cyclooxygenase-2, P=0.003, respectively). This beneficial effect of isoflurane was abolished with DMS and VPC23019. Isoflurane may suppress post-SAH brain inflammation possibly via the sphingosine-related pathway.

Glycemic control with empagliflozin, a novel selective SGLT2 inhibitor, ameliorates cardiovascular injury and cognitive dysfunction in obese and type 2 diabetic mice.

BACKGROUND: There has been uncertainty regarding the benefit of glycemic control with antidiabetic agents in prevention of diabetic macrovascular disease. Further development of novel antidiabetic agents is essential for overcoming the burden of diabetic macrovascular disease. The renal sodium glucose co-transporter 2 (SGLT2) inhibitor is a novel antihyperglycemic agent for treatment of type 2 diabetes. This work was performed to determine whether empagliflozin, a novel SGLT2 inhibitor, can ameliorate cardiovascular injury and cognitive decline in db/db mouse, a model of obesity and type 2 diabetes. METHODS: (1) Short-term experiment: The first experiment was performed to examine the effect of 7 days of empagliflozin treatment on urinary glucose excretion and urinary electrolyte excretion in db/db mice. (2) Long-term experiment: The second experiment was undertaken to examine the effect of 10 weeks of empagliflozin treatment on cardiovascular injury, vascular dysfunction, cognitive decline, and renal injury in db/db mice. RESULTS: (1) Short-term experiment: Empagliflozin administration significantly increased urinary glucose excretion, urine volume, and urinary sodium excretion in db/db mice on day 1, but did not increase these parameters from day 2. However, blood glucose levels in db/db mice were continuously decreased by empagliflozin throughout 7 days of the treatment. (2) Long-term experiment: Empagliflozin treatment caused sustained decrease in blood glucose in db/db mice throughout 10 weeks of the treatment and significantly slowed the progression of type 2 diabetes. Empagliflozin significantly ameliorated cardiac interstitial fibrosis, pericoronary arterial fibrosis, coronary arterial thickening, cardiac macrophage infiltration, and the impairment of vascular dilating function in db/db mice, and these beneficial effects of empagliflozin were associated with attenuation of oxidative stress in cardiovascular tissue of db/db mice. Furthermore, empagliflozin significantly prevented the impairment of cognitive function in db/db mice, which was associated with the attenuation of cerebral oxidative stress and the increase in cerebral brain-derived neurotrophic factor. Empagliflozin ameliorated albuminuria, and glomerular injury in db/db mice. CONCLUSIONS: Glycemic control with empagliflozin significantly ameliorated cardiovascular injury and remodeling, vascular dysfunction, and cognitive decline in obese and type 2 diabetic mice. Thus, empagliflozin seems to be potentially a promising therapeutic agent for diabetic macrovascular disease and cognitive decline.

DPP-4 inhibitor linagliptin ameliorates cardiovascular injury in salt-sensitive hypertensive rats independently of blood glucose and blood pressure.

BACKGROUND: It remains to be elucidated whether dipeptidylpeptidase-4 (DPP-4) inhibitor can ameliorate cardiovascular injury in salt-sensitive hypertension. The present study was undertaken to test our hypothesis that linagliptin, a DPP-4 inhibitor, administration initiated after onset of hypertension and cardiac hypertrophy can ameliorate cardiovascular injury in Dahl salt-sensitive hypertensive rats (DS rats). METHODS: High-salt loaded DS rats with established hypertension and cardiac hypertrophy were divided into two groups, and were orally given (1) vehicle or (2) linagliptin (3 mg/kg/day) once a day for 4 weeks, and cardiovascular protective effects of linagliptin in DS rats were evaluated. RESULTS: Linagliptin did not significantly affect blood pressure and blood glucose levels in DS rats. Linagliptin significantly lessened cardiac hypertrophy in DS rats, as estimated by cardiac weight and echocardiographic parameters. Linagliptin significantly ameliorated cardiac fibrosis, cardiac macrophage infiltration, and coronary arterial remodeling in DS rats. Furthermore, linagliptin significantly mitigated the impairment of vascular function in DS rats, as shown by the improvement of acetylcholine-induced or sodium nitroprusside-induced vascular relaxation by linagliptin. These cardiovascular protective effects of linagliptin were associated with the attenuation of oxidative stress, NADPH oxidase subunits, p67phox and p22 phox, and angiotensin-converting enzyme (ACE). CONCLUSIONS: Our results provided the experimental evidence that linagliptin treatment initiated after the appearance of hypertension and cardiac hypertrophy protected against cardiovascular injury induced by salt-sensitive hypertension, independently of blood pressure and blood glucose. These beneficial effects of linagliptin seem to be attributed to the reduction of oxidative stress and ACE.

Rosuvastatin ameliorates early brain injury after subarachnoid hemorrhage via suppression of superoxide formation and nuclear factor-kappa B activation in rats.

BACKGROUND: Statins, or 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, have been suggested to possess pleiotropic effects, including antioxidant and anti-inflammatory properties. We investigated the protective effects of pretreatment with rosuvastatin, a relatively hydrophilic statin, on early brain injury (EBI) after a subarachnoid hemorrhage (SAH), using the endovascular perforation SAH model. METHODS: Eighty-six male Sprague-Dawley rats were randomly divided into 3 groups: (1) sham operation, (2) SAH+vehicle, and (3) SAH+10 mg/kg rosuvastatin. Rosuvastatin or vehicle was orally administered to rats once daily from 7 days before to 1 day after the SAH operation. After SAH, we examined the effects of rosuvastatin on the neurologic score, brain water content, neuronal cell death estimated by terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate nick end labeling staining, blood-brain barrier disruption by immunoglobulin G (IgG) extravasation, oxidative stress, and proinflammatory molecules. RESULTS: Compared with the vehicle group, rosuvastatin significantly improved the neurologic score and reduced the brain water content, neuronal cell death, and IgG extravasation. Rosuvastatin inhibited brain superoxide production, nuclear factor-kappa B (NF-κB) activation, and the increase in activated microglial cells after SAH. The increased expressions of tumor necrosis factor-alpha, endothelial matrix metalloproteinase-9, and neuronal cyclooxygenase-2 induced by SAH were prevented by rosuvastatin pretreatment. CONCLUSIONS: The present study demonstrates that rosuvastatin pretreatment ameliorates EBI after SAH through the attenuation of oxidative stress and NF-κB-mediated inflammation.

Perivascular macrophages in cerebrovascular diseases.

Cerebrovascular diseases are a major cause of stroke and dementia, both requiring long-term care. These diseases involve multiple pathophysiologies, with mitochondrial dysfunction being a crucial contributor to the initiation of inflammation, apoptosis, and oxidative stress, resulting in injuries to neurovascular units that include neuronal cell death, endothelial cell death, glial activation, and blood-brain barrier disruption. To maintain brain homeostasis against these pathogenic conditions, brain immune cells, including border-associated macrophages and microglia, play significant roles as brain innate immunity cells in the pathophysiology of cerebrovascular injury. Although microglia have long been recognized as significant contributors to neuroinflammation, attention has recently shifted to border-associated macrophages, such as perivascular macrophages (PVMs), which have been studied based on their crucial roles in the brain. These cells are strategically positioned around the walls of brain vessels, where they mainly perform critical functions, such as perivascular drainage, cerebrovascular flexibility, phagocytic activity, antigen presentation, activation of inflammatory responses, and preservation of blood-brain barrier integrity. Although PVMs act as scavenger and surveillant cells under normal conditions, these cells exert harmful effects under pathological conditions. PVMs detect mitochondrial dysfunction in injured cells and implement pathological changes to regulate brain homeostasis. Therefore, PVMs are promising as they play a significant role in mitochondrial dysfunction and, in turn, disrupt the homeostatic condition. Herein, we summarize the significant roles of PVMs in cerebrovascular diseases, especially ischemic and hemorrhagic stroke and dementia, mainly in correlation with inflammation. A better understanding of the biology and pathobiology of PVMs may lead to new insights on and therapeutic strategies for cerebrovascular diseases.