Spatial memory requires hypocretins to elevate medial entorhinal gamma oscillations.

The hypocretin (Hcrt) (also known as orexin) neuropeptidic wakefulness-promoting system is implicated in the regulation of spatial memory, but its specific role and mechanisms remain poorly understood. In this study, we revealed the innervation of the medial entorhinal cortex (MEC) by Hcrt neurons in mice. Using the genetically encoded G-protein-coupled receptor activation-based Hcrt sensor, we observed a significant increase in Hcrt levels in the MEC during novel object-place exploration. We identified the function of Hcrt at presynaptic glutamatergic terminals, where it recruits fast-spiking parvalbumin-positive neurons and promotes gamma oscillations. Bidirectional manipulations of Hcrt neurons' projections from the lateral hypothalamus (LHHcrt) to MEC revealed the essential role of this pathway in regulating object-place memory encoding, but not recall, through the modulation of gamma oscillations. Our findings highlight the significance of the LHHcrt-MEC circuitry in supporting spatial memory and reveal a unique neural basis for the hypothalamic regulation of spatial memory.

Bufalin Inhibits Tumorigenesis and SREBP-1-Mediated Lipogenesis in Hepatocellular Carcinoma via Modulating the ATP1A1/CA2 Axis.

Altered lipid metabolism is a hallmark of hepatocellular carcinoma (HCC), a common malignancy with a dismal prognosis against which there is a lack of effective therapeutic strategies. Bufalin, a classical Na[Formula: see text]-K[Formula: see text]-ATPase (NKA) inhibitor, shows a potent antitumor effect against HCC. However, the role of bufalin in regulating lipid metabolism-related pathways of HCC remains unclear. In this study, we examined the interaction between bufalin and its target molecule, ATP1A1/CA2, in vitro and in vivo and explored the intersected downstream pathways in silico. A multi-omics analysis of transcriptomics and metabolomics was employed to screen for potential action targets. The results were verified and correlated with the downstream lipid de novo synthesis pathway and the bufalin/ATP1A1/CA2 axis. We found that bufalin suppressed the ATP1A1/CA2 ratio in the treated HCC cells and showed a negative correlation with bufalin drug sensitivity. Functionally, ATP1A1 overexpression and CA2 down-regulation inhibited the bufalin-suppressed HCC proliferation and metastasis. Furthermore, down-regulation of CA2 induced epithelial-mesenchymal transition and bufalin resistance in HCC cells by up-regulating ATP1A1. Mechanistically, lipid metabolism-related signaling pathways were enriched in low ATP1A1 and high CA2 expression subgroups in GSEA. The multi-omics analysis also showed that bufalin was closely related to lipid metabolism. We demonstrated that bufalin inhibits lipogenesis and tumorigenesis by down-regulating SREBP-1/FASN/ACLY via modulating the ATP1A1/CA2 axis in HCC.

Advances in Single-component inorganic nanostructures for photoacoustic imaging guided photothermal therapy.

Phototheranostic based on photothermal therapy (PTT) and photoacoustic imaging (PAI), as one of avant-garde medical techniques, have sparked growing attention because it allows noninvasive, deeply penetrative, and highly selective and effective therapy. Among a variety of phototheranostic nanoagents, single-component inorganic nanostructures are found to be novel and attractive PAI and PTT combined nanotheranostic agents and received tremendous attention, which not only exhibit structural controllability, high tunability in physiochemical properties, size-dependent optical properties, high reproducibility, simple composition, easy functionalization, and simple synthesis process, but also can be endowed with multiple therapeutic and imaging functions, realizing the superior therapy result along with bringing less foreign materials into body, reducing systemic side effects and improving the bioavailability. In this review, according to their synthetic components, conventional single-component inorganic nanostructures are divided into metallic nanostructures, metal dichalcogenides, metal oxides, carbon based nanostructures, upconversion nanoparticles (UCNPs), metal organic frameworks (MOFs), MXenes, graphdiyne and other nanostructures. On the basis of this category, their detailed applications in PAI guide PTT of tumor treatment are systematically reviewed, including synthesis strategies, corresponding performances, and cancer diagnosis and therapeutic efficacy. Before these, the factors to influence on photothermal effect and the principle of in vivo PAI are briefly presented. Finally, we also comprehensively and thoroughly discussed the limitation, potential barriers, future perspectives for research and clinical translation of this single-component inorganic nanoagent in biomedical therapeutics.

Hydrogen Sulfide-Induced Vasodilation: The Involvement of Vascular Potassium Channels.

Hydrogen sulfide (H2S) has been highlighted as an important gasotransmitter in mammals. A growing number of studies have indicated that H2S plays a key role in the pathophysiology of vascular diseases and physiological vascular homeostasis. Alteration in H2S biogenesis has been reported in a variety of vascular diseases and H2S supplementation exerts effects of vasodilation. Accumulating evidence has shown vascular potassium channels activation is involved in H2S-induced vasodilation. This review aimed to summarize and discuss the role of H2S in the regulation of vascular tone, especially by interaction with different vascular potassium channels and the underlying mechanisms.

Homocysteine-Induced Disturbances in DNA Methylation Contribute to Development of Stress-Associated Cognitive Decline in Rats.

Chronic stress is generally accepted as the main risk factor in the development of cognitive decline; however, the underlying mechanisms remain unclear. Previous data have demonstrated that the levels of homocysteine (Hcy) are significantly elevated in the plasma of stressed animals, which suggests that Hcy is associated with stress and cognitive decline. To test this hypothesis, we analyzed the cognitive function, plasma concentrations of Hcy, and brain-derived neurotropic factor (BDNF) levels in rats undergoing chronic unpredicted mild stress (CUMS). The results showed that decreased cognitive behavioral performance and decreased BDNF transcription and protein expression were correlated with hyperhomocysteinemia (HHcy) levels in stressed rats. Diet-induced HHcy mimicked the cognitive decline and BDNF downregulation in the same manner as CUMS, while Hcy reduction (by means of vitamin B complex supplements) alleviated the cognitive deficits and BDNF reduction in CUMS rats. Furthermore, we also found that both stress and HHcy disturbed the DNA methylation process in the brain and induced DNA hypermethylation in the BDNF promoter. In contrast, control of Hcy blocked BDNF promoter methylation and upregulated BDNF levels in the brain. These results imply the possibility of a causal role of Hcy in stress-induced cognitive decline. We also used ten-eleven translocation (TET1), an enzyme that induces DNA demethylation, to verify the involvement of Hcy and DNA methylation in the regulation of BDNF expression and the development of stress-related cognitive decline. The data showed that TET1-expressing viral injection into the hippocampus inhibited BDNF promoter methylation and significantly mitigated the cognitive decline in HHcy rats. Taken together, novel evidence from the present study suggests that Hcy is likely involved in chronic stress-induced BDNF reduction and related cognitive deficits. In addition, the negative side-effects of HHcy may be associated with Hcy-induced DNA hypermethylation in the BDNF promoter. The results also suggest the possibility of Hcy as a target for therapy and the potential value of vitamin B intake in preventing stress-induced cognitive decline.

Association of Tai Chi exercise with physical and neurocognitive functions, frailty, quality of life and mortality in older adults: Singapore Longitudinal Ageing Study.

BACKGROUND: real-world observations on the long-term benefits of Tai Chi (TC) exercise, in terms of physical and cognitive functioning, frailty, quality of life (QOL) and mortality are lacking. METHODS: prospective cohort study participants were community-dwelling adults aged 55+, including 5,407 non-frequent TC participants (<1x/week) and 572 frequent TC participants (≥1x/week). Outcome measures at baseline and 3-5 years follow-up included physical performance (Knee Extension Strength, POMA Balance and Gait, Timed-up-and-go, Gait Speed) and neurocognitive performance (attention and working memory, visual-motor tracking and mental flexibility, verbal learning and memory, visual memory, spatial and constructional ability), Frailty Index ≥0.10, impaired QOL (SF12 physical and mental component) and all-cause mortality from mean 13 years follow-up. Effect estimates were adjusted for socio-demographics, other physical activities, nutritional risk and presence of cardiometabolic diseases. RESULTS: frequent TC participation was associated with 0.7-fold lower prevalence of impaired physical QOL [95% confidence interval (CI) = 0.57-0.91], decreased 0.4-fold odds of incident prefrailty/frailty among robust participants at baseline and 0.7-fold odds of impaired mental QOL at follow-up among participants with normal mental QOL at baseline. Lower odds of mortality risk (HR = 0.89, 95%CI = 0.72-1.09) were not significant after controlling for socioeconomic, behavioural and health factors. Composite indexes of physical functional and neurocognitive performance were maintained at high level or increased at follow-up among frequent TC participants. CONCLUSION: TC exercise practised among community-dwelling older adults is associated with better physical, cognitive and functional wellbeing.

Soilless revegetation: An efficient means of improving physicochemical properties and reshaping microbial communities of high-salty gold mine tailings.

Soilless revegetation is a cost-effective and eco-friendly method for the ecological restoration of gold mine tailings. However, due to gold mine tailings are high-salty, alkaline and low-nutrient, little research has been done on soilless revegetation of gold mine tailings. The aim of study was to apply soilless revegetation to gold mine tailings, and investigate the changes of physicochemical properties and microbial communities of tailings after soilless revegetation. Six selected herbaceous plants (Melilotus officinalis, Xanthium sibiricum, Festuca elata, Zoysia japonica, Amaranthus tricolor L., Artemisia desertorum) grew well on the bare tailings, and their heights reached as high as 16.28 cm after 90 days. After soilless revegetation, tailings salinity dramatically dropped from 547.15 to 129.24 µS cm-1, and pH went down from 8.68 to 7.59 at most. The content of available phosphorus (AP), available nitrogen (AN) and organic matter (OM) in tailings gradually improved, especially the content of AP and OM increased 53.36% and 52.58%, respectively. Furthermore, microbial metabolic activity and diversity in tailings obviously increased 70.33-264.70% and 1.64-13.97% respectively. The relative abundance of potential plant growth-promoting bacteria increased 1.40-3.05%, while the relative abundance of opportunistic pathogens and halophilic bacteria decreased 10.58-17.03% and 2.98-6.52% respectively. Such variations of microbial communities were beneficial for tailings restoration. This study provided insight into soilless revegetation and its impact on tailings microorganisms, which could be a new strategy for ecological restoration of gold mine tailings.

Immunomodulatory effects of ablation therapy on tumors: Potentials for combination with immunotherapy.

As a promising area of tumor treatment, immunotherapies, such as immune checkpoint inhibitors, have been applied to various types of cancer. However, many patients do not respond to such therapies. Increasing application of tumor ablation therapy, a minimally invasive treatment, has been observed in the clinic. Although it can boost the anti-tumor immune response of patients in many ways, ablation alone is not sufficient to remove the tumor completely or stop tumor recurrence in the long term. Currently, there is emerging research focusing on ablation in combination with immunotherapy, aiming to confirm the therapeutic value of this treatment for cancer patients. Hence, in this article, we review the classification, guideline recommendations, and immunomodulatory effects of ablation therapy, as well as the pre-clinical and clinical research of this combination therapy.

Targeted and NIR light-controlled delivery of nitric oxide combined with a platinum(iv) prodrug for enhanced anticancer therapy.

This study reports a strategy of combining a Pt(iv) prodrug and a ruthenium nitrosyl (Ru-NO) donor into a single nanoplatform {N-GQDs@Ru-NO-Pt@FA} in which the platinum(iv) prodrug is conjugated onto a photoactivatable NO donor (Ru-NO) through a covalent bond and the nitric oxide-releasing platinum prodrug and folate groups are decorated on N-doped graphene quantum dots (N-GQDs). After cellular uptake of the nanoplatform, the platinum(iv) prodrug was reduced to an active anti-cancer Pt(ii) species inside the cancerous cells, and simultaneously, near-infrared (NIR) light illumination induced the release of NO, accompanied by a prominent photothermal effect. This nanoplatform is capable of targeting intracellular co-delivery of Pt(ii) and NO under 808 nm NIR light irradiation, accompanied by photothermal therapy, thereby leading to a significant synergistic therapeutic effect.

[Protective effect of notoginsenoside R1 on neuron injury induced by OGD/R through ATF6/Akt signaling pathway].

Notoginsenoside R1(NGR1),a critical compound in traditional herb Panax notoginseng, is a kind of estrogen receptor agonist.It is reported to exhibit anti-apoptotic,anti-oxidative and anti-inflammatory properties activity, so it is widely used for treatment of various diseases.In order to investigate the potential neuroprotective effect of NGR1 in hypoxic-ischemic brain damage(HIBD), primary cortical neurons were used in this study to establish oxygen-glucose deprivation/reoxygenation(OGD/R) injury models. They were treated with NGR1 and estrogen receptor inhibitor ICI-182780 respectively, then the neuronal survival, cell membrane integrity and apoptosis were assessed by MTT assay,lactate dehydrogenase test(LDH) and Hoechst 33342 stain respectively, while the protein expression levels of ATF6α,p-Akt,Akt,Bax and Cleaved Caspase-3 were measured by Western blotting. Results indicated that as compared with the blank control group,OGD/R could induce cell injury and apoptosis(P<0.05), reduce relative integrity of cell membrane(P<0.05), decrease protein expression of ATF6α,p-Akt(P<0.05), and increase protein expression of Bax and Cleaved Caspase-3(P<0.05) in the primary cortical cells. After NGR1 treatment, the expression levels of ATF6α,p-Akt were obviously increased, and the expression levels of Bax and Cleaved Caspase-3 and the apoptosis of neuron were decreased(P<0.05). However, these neuroprotective properties of NGR1 against ODG/R-induced cell damage could be blocked by ICI-182780. This finding indicated that NGR1 may protect the primary cortical neurons against OGD/R induced injury,and the mechanism may be associated with accelerating the activation of the ATF6/Akt signaling pathway via estrogen receptors.

Inhibition of HDAC3 prevents diabetic cardiomyopathy in OVE26 mice via epigenetic regulation of DUSP5-ERK1/2 pathway.

Inhibition of total histone deacetylases (HDACs) was phenomenally associated with the prevention of diabetic cardiomyopathy (DCM). However, which specific HDAC plays the key role in DCM remains unclear. The present study was designed to determine whether DCM can be prevented by specific inhibition of HDAC3 and to elucidate the mechanisms by which inhibition of HDAC3 prevents DCM. Type 1 diabetes OVE26 and age-matched wild-type (WT) mice were given the selective HDAC3 inhibitor RGFP966 or vehicle for 3 months. These mice were then killed immediately or 3 months later for cardiac function and pathological examination. HDAC3 activity was significantly increased in the heart of diabetic mice. Administration of RGFP966 significantly prevented DCM, as evidenced by improved diabetes-induced cardiac dysfunction, hypertrophy, and fibrosis, along with diminished cardiac oxidative stress, inflammation, and insulin resistance, not only in the mice killed immediately or 3 months later following the 3-month treatment. Furthermore, phosphorylated extracellular signal-regulated kinases (ERK) 1/2, a well-known initiator of cardiac hypertrophy, was significantly increased, while dual specificity phosphatase 5 (DUSP5), an ERK1/2 nuclear phosphatase, was substantially decreased in diabetic hearts. Both of these changes were prevented by RGFP966. Chromatin immunoprecipitation (ChIP) assay showed that HDAC3 inhibition elevated histone H3 acetylation on the DUSP5 gene promoter at both two time points. These findings suggest that diabetes-activated HDAC3 inhibits DUSP5 expression through deacetylating histone H3 on the primer region of DUSP5 gene, leading to the derepression of ERK1/2 and the initiation of DCM. The present study indicates the potential application of HDAC3 inhibitor for the prevention of DCM.

A ruthenium-nitrosyl-functionalized nanoplatform for the targeting of liver cancer cells and NIR-light-controlled delivery of nitric oxide combined with photothermal therapy.

The development of light-controlled nitric oxide (NO)-releasing nanoplatforms that are capable of specifically targeting liver cancer cell lines and delivering an optimal amount of NO can significantly affect liver cancer therapy. In this study, a multifunctional nanoplatform {N-GQDs@Ru-NO@Gal} (1) for the near-infrared (NIR) light-responsive release of NO, consisting of a NO donor (Ru-NO) and a liver-targeting galactose derivative (Gal) covalently attached to N-doped graphene quantum dots (N-GQDs), was reported. Nanoplatform 1 preferentially targeted liver cancer cells over normal cells and instantly released NO as well as exhibited a prominent photothermal effect upon NIR irradiation at 808 nm, thereby leading to efficient anti-tumor efficacy. {N-GQDs@Ru-NO@Gal} with a small size (<10 nm), good biocompatibility, and fluorescent-tracing properties represents a unique example of a multifunctional NO-releasing nanoplatform that combines photodynamic and photothermal therapies for the targeted treatment of liver cancer. Hence, the developed nanoplatform demonstrates potential for applications in NO-mediated multimodal phototherapy in the near future.

The involvement of homocysteine in stress-induced Aß precursor protein misprocessing and related cognitive decline in rats.

Chronic stress is a risk factor in the development of cognitive decline and even Alzheimer's disease (AD), although its underlying mechanism is not fully understood. Our previous data demonstrated that the level of homocysteine (Hcy) was significantly elevated in the plasma of stressed animals, which suggests the possibility that Hcy is a link between stress and cognitive decline. To test this hypothesis, we compared the cognitive function, plasma concentrations of Hcy, and the brain beta-amyloid (Aß) level between rats with or without chronic unexpected mild stress (CUMS). A lower performance by rats in behavioral tests indicated that a significant cognitive decline was induced by CUMS. Stress also disturbed the normal processing of Aß precursor protein (APP) and resulted in the accumulation of Aß in the brains of rats, which showed a positive correlation with the hyperhomocysteinemia (HHcy) that appeared in stressed rats. Hcy-targeting intervention experiments were used to verify further the involvement of Hcy in stress-induced APP misprocessing and related cognitive decline. The results showed that diet-induced HHcy could mimic the cognitive impairment and APP misprocessing in the same manner as CUMS, while Hcy reduction by means of vitamin B complex supplements and betaine could alleviate the cognitive deficits and dysregulation of Aß metabolism in CUMS rats. Taken together, the novel evidence from our present study suggests that Hcy is likely to be involved in chronic stress-evoked APP misprocessing and related cognitive deficits. Our results also suggested the possibility of Hcy as a target for therapy and the potential value of vitamin B and betaine intake in the prevention of stress-induced cognitive decline.

Comparative effectiveness and tolerance of treatments for Helicobacter pylori: systematic review and network meta-analysis.

OBJECTIVE: To determine the most efficacious treatment for eradication of Helicobacter pylori with the lowest likelihood of some common adverse events among pre-recommended and newer treatment regimens. DESIGN: Systematic review and network meta-analysis. DATA SOURCES: Cochrane Library, PubMed, and Embase without language or date restrictions. STUDY SELECTION: Full text reports of randomised controlled trials that compared different eradication treatments for H pylori among adults. RESULTS: Of the 15,565 studies identified, 143 were eligible and included. Data on 14 kinds of treatments were available. Of 91 possible comparisons for the efficacy outcome, 34 were compared directly and the following treatments performed better: seven days of concomitant treatment (proton pump inhibitor and three kinds of antibiotics administered together), 10 or 14 days of concomitant treatment, 10 or 14 days of probiotic supplemented triple treatment (standard triple treatment which is probiotic supplemented), 10 or 14 days of levofloxacin based triple treatment (proton pump inhibitor, levofloxacin, and antibiotic administered together), 14 days of hybrid treatment (proton pump inhibitor and amoxicillin used for seven days, followed by a proton pump inhibitor, amoxicillin, clarithromycin, and 5-nitroimidazole for another seven days), and 10 or 14 days of sequential treatment (five or seven days of a proton pump inhibitor plus amoxicillin, followed by five or seven additional days of a proton pump inhibitor plus clarithromycin and 5-nitroimidazole or amoxicillin). In terms of tolerance, all treatments were considered tolerable, but seven days of probiotic supplemented triple treatment and seven days of levofloxacin based triple treatment ranked best in terms of the proportion of adverse events reported. CONCLUSION: Comparison of different eradication treatments for H pylori showed that concomitant treatments, 10 or 14 days of probiotic supplemented triple treatment, 10 or 14 days of levofloxacin based triple treatment, 14 days of hybrid treatment, and 10 or 14 days of sequential treatment might be better alternatives for the eradication of H pylori.

Critical role of YY1 in cardiac morphogenesis.

BACKGROUND: Yin Yang 1 (YY1), the only DNA binding polycomb group protein, was reported to regulate cardiomyocyte differentiation during early cardiac mesoderm development. However, whether it contributes to cardiac morphogenesis at later developmental stage(s) during embryogenesis is unknown. RESULTS: We excised YY1 in murine hearts during embryogenesis using two temporal-spatially controlled cre activation approaches, and revealed critical roles of YY1 in cardiac structural formation. Alpha-myosin heavy chain-cre (α-MHC-cre)-mediated cardiomyocyte-specific ablation of YY1 (MHC-YY1) resulted in perinatal death of mutant mice, and Nkx2.5-cre-mediated YY1 null embryos (Nkx2.5-YY1) died embryonically. In the Nkx2.5-YY1 mutants, the endocardial cushions (ECs) of both atrioventricular canal (AVC) and outflow tract (OFT) were hypoplastic due to decreased proliferation and increased apoptosis. Endothelial-to-mesenchymal transition (EMT) progress was also compromised in ECs. Nkx2.5-YY1 mutant hearts had normal formation of extracellular matrix, suggesting that the impaired EMT resulted from the direct loss of YY1. We further uncovered that a number of factors that are involved in normal cardiogenesis were downstream targets of YY1. CONCLUSIONS: YY1 plays a critical role in cardiac development and occupies a high-level position within the hierarchy of the cardiac transcriptional network that governs normal cardiogenesis.

Endothelium-dependent and -independent vasorelaxant actions and mechanisms induced by total flavonoids of Elsholtzia splendens in rat aortas.

Elsholtzia splendens (ES) is, rich in flavonoids, used to repair copper contaminated soil in China, which has been reported to benefit cardiovascular systems as folk medicine. However, few direct evidences have been found to clarify the vasorelaxation effect of total flavonoids of ES (TFES). The vasoactive effect of TFES and its underlying mechanisms in rat thoracic aortas were investigated using the organ bath system. TFES (5-200mg/L) caused a concentration-dependent vasorelaxation in endothelium-intact rings, which was not abolished but significantly reduced by the removal of endothelium. The nitric oxide synthase (NOS) inhibitor N(ω)-nitro-l-arginine methyl ester (100µM) and the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,2-α]quinoxalin-1-one (30µM) significantly blocked the endothelium-dependent vasorelaxation of TFES. Meanwhile, NOS activity in endothelium-intact aortas was concentration-dependently elevated by TFES. However, indomethacin (10µM) did not affect TFES-induced vasorelaxation. Endothelium-independent vasorelaxation of TFES was significantly attenuated by KATP channel blocker glibenclamide. The accumulative Ca(2+)-induced contraction in endothelium-denuded aortic rings primed with KCl or phenylephrine was markedly weakened by TFES. These results revealed that the NOS/NO/cGMP pathway is likely involved in the endothelium-dependent vasorelaxation induced by TFES, while activating KATP channel, inhibiting intracellular Ca(2+) release, blocking Ca(2+) channels and decreasing Ca(2+) influx into vascular smooth muscle cells might contribute to the endothelium-independent vasorelaxation conferred by TFES.

Ventricular hypertrophy abrogates intralipid-induced cardioprotection by alteration of reperfusion injury salvage kinase/glycogen synthase kinase 3ß signal.

Recent studies have demonstrated that intralipid (ILP) conferred myocardial protection against ischemia-reperfusion (IR) injury through activation of reperfusion injury salvage kinase (RISK) pathway. As RISK signal has been shown to be impaired in hypertrophied myocardium, we investigated whether ILP-induced cardiac protection was maintained in hypertrophied rat hearts. Transverse aortic constriction was performed on male Sprague-Dawley rats to induce left ventricular hypertrophy, then sham-operated or hypertrophied rat hearts were isolated and perfused retrogradely by the Langendorff for 30 min (equilibration) followed by 40 min of ischemia and then 120 min of reperfusion. The isolated hearts received 15-min episode of 1% ILP separated by 15 min of washout or three episodes of 5-min ischemia followed by 5-min reperfusion before ischemia. The hemodynamics, infarct size, apoptosis, phosphorylated protein kinase B (p-Akt), phosphorylated extracellular regulated protein kinase 1/2 (ERK1/2), phosphorylated glycogen synthase kinase 3ß (GSK3ß), Bcl-2, phosphorylated Bad, and Bax were determined. We found that ILP significantly improved left ventricular hemodynamics and reduced infarct size and the number of TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling)-positive cells in the sham-operated rat hearts exposed to IR. However, such myocardial infarct-sparing effect of ILP was completely blocked by phosphatidylinositol-3-kinase inhibitor wortmannin, but only partially by mitogen-activated protein kinase kinase inhibitor PD98059 in sham-operated hearts. Intralipd upregulated the phosphorylation of Akt, extracellular regulated protein kinase 1/2 (ERK1/2), and their downstream target of GSK3ß and antiapoptotic Bcl-2 expression in healthy rat hearts. Nonetheless, ILP failed to improve left ventricular hemodynamics and reduced infarct size and apoptosis and increase the phosphorylated Akt, ERK1/2, GSK3ß, and antiapoptotic Bcl-2 in hypertrophied myocardium. In contrast, ischemic preconditioning increased the phosphorylation of Akt, ERK1/2 and GSK3ß, improved heart pump function, and reduced myocardial necrosis in sham-operated hearts, a phenomenon partially attenuated by ventricular hypertrophy. Interestingly, GSK inhibitor SB216763 conferred cardioprotection against IR injury in sham-operated hearts, but failed to exert cardioprotection in hypertrophied myocardium. Our results indicated that ventricular hypertrophy abrogated ILP-induced cardioprotection against IR injury by alteration of RISK/GSK3ß signal.

Hemodynamic contribution of stem cell scaffolding in acute injured myocardium.

Tissue-engineered scaffolds may improve experimental outcomes in cardiac cell therapy by targeted delivery of stem cells and mechanically support an infarcted left ventricular (LV) wall. We transplanted cardiomyocyte-like cells (5×10(5)) with scaffolding via epicardial patching (cell patch, n=17) or a low-dose intramyocardial hydrogel (LD hydrogel, n=18), a high-dose (5×10(6)) intramyocardial hydrogel (HD hydrogel, n=18) or transplanting a serum-free medium control (control, n=13), a blank patch (n=14), and a blank gel (n=16) for targeted cardiomyoplasty in a myocardial infarcted rat model. LV real-time hemodynamics were assessed using a 1.9-F pressure-volume catheter 7 weeks after stem cell transplantation. All mode of scaffold transplantation protected diastolic function by preserving LV wall integrity that resulted in a lower end diastolic pressure-volume relationship (EDPVR) as compared to a control medium-injected group. Moreover, epicardial patching, but not hydrogel injection, reduced ventricular wall stress with a significantly better LV end diastolic pressure (EDP: 5.3±2.4 mmHg vs. 9.6±6.9 mmHg, p<0.05) as compared to control. Furthermore, epicardial patching additionally preserved systolic function by modulating negative remodeling through restricting dilatation of the LV chamber. In comparison to control, an improved ejection fraction in the cell patch group (80.1%±5.9% vs. 67.9%±3.2%, p<0.01) was corroborated by load-independent enhancement of the end systolic pressure-volume relationship (ESPVR: 0.88±0.61 mmHg/uL vs. 0.29±0.19 mmHg/uL, p<0.05) and preload recruitable stroke work (PRSW: 68.7±26.4 mmHg vs. 15.6±16.2 mmHg, p<0.05) in systolic function. Moreover, the cell patch group (14.2±1.7 cells/high-power field vs. 7.4±1.6 cells/high power field, p<0.05) was significantly better in myocardial retention of transplanted stem cells as compared to the LD hydrogel group. Collectively, myocardial transplantation of compliant scaffolding materials alone may physically improve wall mechanics, largely independent of stem cells. However, epicardially grafted cell patch conferred added systolic contractility by improving stem cell retention and cellular alignment leading to improved LV remodeling and geometric preservation postinfarction.

Betulinic acid ameliorates endothelium-dependent relaxation in L-NAME-induced hypertensive rats by reducing oxidative stress.

Zizyphi Spinosi semen (ZSS) is one of the most widely used traditional Chinese herbs with protective effects on the cardiovascular system. It is not clear whether betulinic acid (BA), the key active constituent of ZSS, has beneficial cardiovascular effects on N(ω)-nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats. The objective of this study was to investigate the effect of BA on endothelium-dependent vasorelaxation in isolated aortic rings from L-NAME-induced hypertensive rats and its underlying mechanisms. Male Sprague-Dawley rats were injected with L-NAME (15 mg/kg/d, i.p.) for 4 weeks to induce hypertension. After treatment with L-NAME for 2 weeks, rats with mean blood pressure >120 mm Hg measured by tail-cuff method were considered hypertensive and then injected with BA (0.8, 4, 20 mg/kg/d, i.p.) for the last 2 weeks. The effect of BA on the tension of rat thoracic aortic rings was measured in an organ bath system. The levels of nitric oxide (NO), reactive oxygen species (ROS), and the activity of superoxide dismutase (SOD) and nitric oxide synthase (NOS) in aortas were assayed. We found that BA (0.1-100 µM) evoked a concentration-dependent vasorelaxation in endothelium-intact normal rat aortic rings, which was significantly attenuated by pretreatment with L-NAME (100 µM) or methylene blue (MB, 10 µM), but not by indomethacin (10 µM). Pretreatment with EC(50) (1.67 µM) concentration of BA enhanced the acetylcholine (ACh)-induced vasorelaxation, which was also markedly reversed by both L-NAME and MB. The blood pressure in hypertensive rats increased to 135.22±5.38 mm Hg (P<0.01 vs. control group), which was markedly attenuated by high dose of BA. The ACh-induced vasorelaxation in hypertensive rat aortic rings was impaired, which was markedly improved by chronic treatment with BA (20 mg/kg/d) for 2 weeks. The increase of ROS level and the decrease of NO level, SOD and eNOS activities in hypertensive rat aortas were all markedly inhibited by BA. These results indicate that BA decreased blood pressure and improved ACh-induced endothelium-dependent vasorelaxation in L-NAME-induced hypertension rats, which may be mediated by reducing oxidative stress and retaining the bioavailability of NO in the cardiovascular system.