Research Progress on Insomnia and Microarousal / 中国医学科学院学报

Insomnia is a subjective experience of difficulty in falling asleep and/or maintaining sleep accompanied by the impairment of daytime social functioning due to insufficient sleep quality or quantity to meet normal physiological needs.It has chronic damage to all the human body systems and is the most common sleep disorder.The main mechanism for the occurrence and maintenance of insomnia is the hyperarousal hypothesis,and microarousal,as a cortical arousal,is also involved in the formation of the hyperarousal mechanism.The mechanism and clinical significance of microarousal were reviewed and summarized in this paper in order to guide the clinical work.

Polarized activation affects iron metabolism in macrophages / 生理学报

The aim of this study was to investigate the effects of polarization program on the ability of macrophages to regulate iron metabolism. M1 and M2 macrophages were propagated in vitro from porcine alveolar macrophages 3D4/2 and polarized by cytokines. The 3D4/2 macrophages were treated with 20 ng/mL interferon gamma (IFN-γ) and 10 ng/mL interleukin-4 (IL-4) combined with 10 ng/mL macrophage colony-stimulating factor (M-CSF) to induce polarization to M1 and M2, respectively. After incubation for 24 h, the expression levels of inflammatory factors and iron-metabolism genes were determined using real-time qPCR, Western bot and immunofluorescence. The M1/M2 macrophages culture media supernatant was collected and used to treat porcine intestinal epithelial cells IPEC-J2. The proliferation ability of IPEC-J2 was detected using CCK-8 assay kit. Following exogenous addition of ammonium ferric citrate (FAC) to M1/M2 macrophages, the phagocytic function of macrophages was detected using fluorescein isothiocyanate-dextran (FITC-dextran) and flow cytometry. The results showed that, compared with control, M1 macrophages had higher mRNA levels of iron storage proteins (ferritin heavy and light polypeptide, i.e. FtH and FtL), hepcidin and lipocalin-2, as well as iron content. Moreover, iron enhanced the ability of M1 macrophages to phagocytize FITC-dextran. There was no significant change in these mRNA expression levels in M2 macrophages, but the mRNA expression levels of ferroportin and transferrin receptor were up-regulated. In addition, the conditioned media supernatant from M2 macrophages promoted cell proliferation of IPEC-J2. These findings indicate that M1 macrophages tend to lock iron in the cell and reduce extracellular iron content, thereby inhibiting the proliferation of extracellular bacteria. While M2 macrophages tend to excrete iron, which contributes to the proliferation of surrounding cells and thus promotes tissue repair.

Research status and recent advances of nanophthalmos / 中华眼底病杂志

Nanophthalmos is a congenital disorder, which is characterized by small eye without any ocular or systemic malformation. It has autosomal-dominant and recessive forms of inheritance. It manifests as reduced total axial length, high hyperopia and thickened sclera. Nanophthalmos is relatively rare, but at high risk of secondary angle-closure glaucoma, uveal effusion syndrome. It can be spontaneous remission or recurrent, and responses poorly to medication. The effect of systemic glucocorticoid treatment is not ideal. The surgery challenges with very high rate of intra- and post-operative complications such as hemorrhage, choroidal and retinal detachment, malignum glaucoma and uveal effusion, so that the prognosis is poor. It is of great instructive significance to further understand the clinical features, complications and treatment progress and to avoid the missed diagnosis and misdiagnosisi of its complications, and thus choose the right management.

Advance in morphological measurement and functional test for atrophic age-related macular degeneration / 眼科新进展

Age-related macular degeneration (AMD) is the main cause of blindness in the people older than 50 years old,and atrophic age-related macular degeneration accounts for 85％-90％ patients of AMD.Following the application of multi-spectral imaging,fundus autofluorescence,optical coherence tomography,microperimetry,multifocal electroretinogram and other new methods in ophthalmic clinical,the morphological and functional changes of atrophic AMD lesions have been more in-depth and comprehen sive,so this article will give a review on the relevant progress of examination techniques in recent years.

Advance in morphological measurement and functional test for atrophic age-related macular degeneration / 眼科新进展

Age-related macular degeneration (AMD) is the main cause of blindness in the people older than 50 years old,and atrophic age-related macular degeneration accounts for 85％-90％ patients of AMD.Following the application of multi-spectral imaging,fundus autofluorescence,optical coherence tomography,microperimetry,multifocal electroretinogram and other new methods in ophthalmic clinical,the morphological and functional changes of atrophic AMD lesions have been more in-depth and comprehen sive,so this article will give a review on the relevant progress of examination techniques in recent years.

Extracellular Matrix Disarray as a Mechanism for Greater Abdominal Versus Thoracic Aortic Stiffness With Aging in Primates.

OBJECTIVE: Increased vascular stiffness is central to the pathophysiology of aging, hypertension, diabetes mellitus, and atherosclerosis. However, relatively few studies have examined vascular stiffness in both the thoracic and the abdominal aorta with aging, despite major differences in anatomy, embryological origin, and relation to aortic aneurysm. APPROACH AND RESULTS: The 2 other unique features of this study were (1) to study young (9±1 years) and old (26±1 years) male monkeys and (2) to study direct and continuous measurements of aortic pressure and thoracic and abdominal aortic diameters in conscious monkeys. As expected, aortic stiffness, ß, was increased P<0.05, 2- to 3-fold, in old versus young thoracic aorta and augmented further with superimposition of acute hypertension with phenylephrine. Surprisingly, stiffness was not greater in old thoracic aorta than in young abdominal aorta. These results can be explained, in part, by the collagen/elastin ratio, but more importantly, by disarray of collagen and elastin, which correlated best with vascular stiffness. However, vascular smooth muscle cell stiffness was not different in thoracic versus abdominal aorta in either young or old monkeys. CONCLUSIONS: Thus, aortic stiffness increases with aging as expected, but the most severe increases in aortic stiffness observed in the abdominal aorta is novel, where values in young monkeys equaled, or even exceeded, values of thoracic aortic stiffness in old monkeys. These results can be explained by alterations in collagen/elastin ratio, but even more importantly by collagen and elastin disarray.

Effects of traditional Tibetan drug Liu Tea on proliferation and chemotherapeutic sensitivity of drug-resistant human gastric cancer cell BGC823/5-FU / 中国中药杂志

To investigate the effects of Liu Tea extracts(LTE) on proliferation, apoptosis and drug sensitivity of drug-resistant gastric cancer cell BGC823/5-FU. MTT assay was used to analyze effect of LTE on cell growth and sensitivity chemotherapeutic drugs, and synergistic effect of the combination of LTE with 5-FU on BGC823/5-FU cells. Combination index (CI) was calculated by CompuSyn. Cell apoptosis was measured by flow cytometry (FCM). Protein expressions of P-gp, Bcl-2, Bax and Caspase-3 (17KD) were detected by Western blot at different concentrations of LTE in BGC823/5-FU cells (100, 200, 400 mg•L⁻¹). The results showed that LTE had an inhibitory effect on growth of BGC823/5-FU cell in a dose-time-dependent manner and significantly reduced IC₅₀ of 5-FU, CDDP, PTX and ADM to BGC823/5-FU cells(P<0.05), indicating it could reverse tolerance of drug resistant cells to chemotherapeutic drugs, with reversion multiples of 2.35, 1.68, 1.96, 0.52. The combination of LTE with 5-FU had positive synergistic effect on the BGC-823 cell line. FCM assay suggested that LTE could induce BGC823/5-FU apoptosis. The apoptosis rate was up to 46.2% when the cells were treated with 800 mg•L⁻¹ LTE after 24 h(P<0.01). According to the protein detection results, with the increase in concentration of LTE, the protein expression of Bcl-2 was gradually decreased(P<0.01), the expression of Bax and Caspase-3 were extremely increased(P<0.01), with statistical significance in difference(P<0.01) but no difference in the expression of P-gp between experiment group and control group. LTE can inhibit the growth of drug-resistant human gastric cancer cell BGC823/5-FU and reverse its chemotherapeutic tolerance to some extent. Inhibition of antiapoptotic proteins, activation of proapoptotic proteins and induction of apoptosis of resistant cells may be its main mechanisms.

GLP-1 (7-36) amide restores myocardial insulin sensitivity and prevents the progression of heart failure in senescent beagles.

BACKGROUND: We previously demonstrated that older beagles have impaired whole body and myocardial insulin responsiveness (MIR), and that glucagon-like peptide-1 (GLP-1 [7-36] amide) improves MIR in young beagles with dilated cardiomyopathy (DCM). Here, we sought to determine if aging alone predisposes to an accelerated course of DCM, and if GLP-1 [7-36] amide would restore MIR and impact the course of DCM in older beagles. METHODS: Eight young beagles (Young-Control) and sixteen old beagles underwent chronic left ventricle (LV) instrumentation. Seven old beagles were treated with GLP-1 (7-36) amide (2.5 pmol/kg/min) for 2 weeks prior to instrumentation and for 35 days thereafter (Old + GLP-1), while other 9 served as control (Old-Control). All dogs underwent baseline metabolic determinations and LV biopsy for mitochondria isolation prior to the development of DCM induced by rapid pacing (240 min-1). Hemodynamic measurements were performed routinely as heart failure progressed. RESULTS: At baseline, all old beagles had elevated non-esterifed fatty acids (NEFA), and impaired MIR. GLP-1 reduced plasma NEFA (Old-Control: 853 ± 34; Old + GLP-1: 531 ± 33 µmol/L, p < 0.02), improved MIR (Old-Control: 289 ± 54; Old + GLP-1: 512 ± 44 mg/min/100 mg, p < 0.05), and increased uncoupling protein-3 (UCP-3) expression in isolated mitochondria. Compared to the Young-Control, the Old-Controls experienced an accelerated course of DCM (7 days versus 29 days, p < 0.005) and excess mortality, while the Old + GLP-1 experienced increased latency to the onset of DCM (7 days versus 23 days, p < 0.005) and reduced mortality. CONCLUSION: Aging is associated with myocardial insulin resistance, which predispose to an accelerated course of DCM. GLP-1 treatment is associated with increased MIR and protection against an accelerated course of DCM in older beagles.

Establishment of a high metastatic potential human hepatocellular carcinoma orthotopic transplantation model with palliative liver resection in nude mice / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To construct a high metastatic potential human hepatocellular carcinoma (HCC) orthotopic transplantation model with palliative liver resection in nude mice.</p><p><b>METHODS</b>A human HCC orthotopic nude mice model was established by administering a single inoculation of the highly metastatic MHCC97H tumor tissue (size 2 mm * 2 mm * 2 mm) into the left liver lobe. At day 14 post-inoculation, a random group of the mice received palliative liver resection; the unresected mice served as controls. Changes in expression levels of 113 genes with metastasis-related functions were evaluated in the residual HCC tissues. At day 35 post-resection, a random group of the mice were sacrificed by cervical dislocation and a comprehensive metastases examination was performed. The remaining mice were used to observe life span. All statistical analyses were performed by the SPSS v17.0 software, and significance was defined as P less than 0.05.</p><p><b>RESULTS</b>The nude mouse model of highly metastatic HCC with palliative liver resection was successfully established. Incidences of intrahepatic and abdominal metastases were higher in the palliative resected group (vs. unresected group: 11.7+/-4.7 vs. 6.3+/-2.8, t = -2.412, P less than 0.05 and 9.8+/-3.4 vs. 5.2+/-2.6, t = -2.641, P less than 0.05 respectively). In addition, the palliative resected group showed significantly enhanced pulmonary metastasis (vs. unresected group: 14.3+/-4.7 vs. 8.7+/-4.7, t = -2.348, P less than 0.05). Differential gene expression levels were found for MTSS1, TGFbl, SMAD2, IL-1b, and MMP7, and were situated in the central position of gene function net of residual HCC. The life-span of the palliative resected group was significantly longer than that of the unresected group (60.8+/-2.7 vs. 51.3+/-1.4 days, x2 = 12.850, P less than 0.01).</p><p><b>CONCLUSION</b>The highly metastatic human HCC nude mouse model with palliative liver resection that was successfully constructed in this study represents a useful investigational tool to assess the biological characteristics of residual cancer and to screen therapeutic strategies.</p>

Effects of the Chinese herbal extract Songyou Yin on the residual hepatocellular carcinoma after chemotherapy in nude mice / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effects of a Chinese herbal extract Songyou Yin on residual hepatocellular carcinoma after chemotherapy in nude mice and the relevant mechanisms.</p><p><b>METHODS</b>Orthotopic nude mouse models bearing residual hepatocellular carcinoma after chemotherapy was established using human liver carcinoma MHCC97L cells. Three different doses of Songyon Yin (2.1 g/kg, 4.2 g/kg and 8.4 g/kg) were administered to the mice in the trial groups by intragastric gavage, respectively. The mice in the control group were administered physiological saline. The tumor growth, metastasis and survival in the mice of each group were recorded. The corresponding mechanisms were studied.</p><p><b>RESULTS</b>The pulmonary metastasis rates of the control group and 2.1g/kg, 4.2g/kg, 8.4g/kg Songyou Yin treatment group were 86.7%, 73.3%, 40.0%, and 20.0%, respectively, and the survivals of these groups were 53.83 ± 4.71, 56.50 ± 6.09, 66.67 ± 5.61, 81.17 ± 7.36 days, respectively. Compared with the mice in the control group, mice in the 4.2 g/kg, 8.4 g/kg Songyou Yin treatment groups had a lower pulmonary metastasis rate (P = 0.021 and P = 0.001, respectively) and longer survival (P = 0.002 and P = 0.001, respectively). A restoration of E-cadherin expression and a concomitant reduction of N-cadherin expression were detected in the tumors of the 4.2 g/kg and 8.4 g/kg Songyou Yin treatment groups.</p><p><b>CONCLUSIONS</b>Songyou Yin effectively inhibits the invasion and metastasis of the residual hepatocellular carcinoma after chemotherapy in nude mice through attenuating the epithelia-mesenchymal transition and prolongs the survival. Songyon Yin may have potential to promote the efficacy of chemotherapy in hepatocellular carcinoma.</p>

Local injection of lentivirus-delivered livinshRNA suppresses lung adenocarcinoma growth by inducing a G0/G1 phase cell cycle arrest.

The inhibitor of apoptosis protein (IAP) plays an important role in tumorigenesis and may be a potential target for cancer therapy. Livin, which belongs to this family, is highly expressed in various tumors. The previous study demonstrated that silencing Livin gene promoted lung cancer cell apoptosis; however, the effects on tumor growth suppression by targeting this gene in vivo, to thereby determine the efficacy of targeting Livin for patient therapy, have not been determined. This study injected lentivirus-delivered livinshRNA into established xenograft tumors derived from the lung adenocarcinoma cell line SPC-A-1 in BALB/C nude mice, the result showed that LivinshRNA down-regulated Livin expression effectively, induced tumor cell apoptosis, reduced tumor cell proliferation, and suppressed tumor growth dramatically, with a tumor volume inhibitory rate of (58.65±4.82)% and a tumor weight inhibitory rate of (47.44±1.64)%, but with less severe adverse reaction to the mouse. This study further demonstrated that Livin gene silencing induced a G0/G1-phase cell cycle arrest and cyclin D1 downregulation, which is a key regulator of the G0/G1- to S-phase transition. These findings suggest that LivinshRNA local injection may serve as a therapeutic method for patient treatment, and that LivinshRNA may suppress tumor growth by arresting the cell cycle in the G0/G1-phase.

Smooth muscle myosin inhibition: a novel therapeutic approach for pulmonary hypertension.

OBJECTIVE: Pulmonary hypertension remains a major clinical problem despite current therapies. In this study, we examine for the first time a novel pharmacological target, smooth muscle myosin, and determine if the smooth muscle myosin inhibitor, CK-2019165 (CK-165) ameliorates pulmonary hypertension. MATERIALS AND METHODS: Six domestic female pigs were surgically instrumented to measure pulmonary blood flow and systemic and pulmonary vascular dynamics. Pulmonary hypertension was induced by hypoxia, or infusion of the thromboxane analog (U-46619, 0.1 µg/kg/min, i.v.). In rats, chronic pulmonary hypertension was induced by monocrotaline. RESULTS: CK-165 (4 mg/kg, i.v.) reduced pulmonary vascular resistance by 22±3 and 28±6% from baseline in hypoxia and thromboxane pig models, respectively (p<0.01 and 0.01), while mean arterial pressure also fell and heart rate rose slightly. When CK-165 was delivered via inhalation in the hypoxia model, pulmonary vascular resistance fell by 17±6% (p<0.05) while mean arterial pressure and heart rate were unchanged. In the monocrotaline model of chronic pulmonary hypertension, inhaled CK-165 resulted in a similar (18.0±3.8%) reduction in right ventricular systolic pressure as compared with sildenafil (20.3±4.5%). CONCLUSION: Inhibition of smooth muscle myosin may be a novel therapeutic target for treatment of pulmonary hypertension.

Changes of metastatic potential of residual hepatocellular carcinoma in nude mice after in vivo chemotherapy and the corresponding mechanisms / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the changes of metastatic potential of residual hepatocellular carcinoma (HCC) after in vivo chemotherapy and its mechanism.</p><p><b>METHODS</b>Nude mouse models of orthotopic HCC in the nude mouse livers was established using human hepatocellular carcinoma cell line MHCC97L cells. Oxaliplatin (10 mg/kg, once per week) was administered intraperitoneally (i.p.) to mice in the trial group. Mice in the control group received 0.2 ml of 0.9% sodium chloride on the same days. On day 7 after the third injection, all mice were sacrificed and tumor fragments of equal volume (2 mm×2 mm×2 mm) from each mouse of the oxaliplatin-treated and untreated groups were reinoculated into the livers of each new recipient mouse correspondingly. The growth, metastasis and molecular phenotype of the reinoculated tumors in both groups were determined.</p><p><b>RESULTS</b>In the new recipient mice, compared with untreated tumors, oxaliplatin pre-treated tumors grew significantly slower [(2624.59 ± 491.60) mm(3) vs. (3849.72 ± 827.09) mm(3), P < 0.001], but gave more spontaneous metastasis to the lung (10/12 vs. 3/12, P = 0.012). A decreased expression of E-cadherin and increased expression of N-cadherin, vimentin and transcription factor Snail were detected in the oxaliplatin pre-treated tumors by immunohistochemistry, which provided the evidence of epithelial mesenchymal transition (EMT) in these tumors.</p><p><b>CONCLUSION</b>Residual hepatocellular carcinomas after in vivo chemotherapy grow slower but gain enhanced metastatic potential to the lung, associated with epithelial mesenchymal transition.</p>

[Mineral information extraction for hyperspectral image based on modified spectral feature fitting algorithm].

Spectral feature fitting (SFF) algorithm has been frequently used since 1990s. A modified spectral feature fitting method is introduced here, which can solve some drawback of the general algorithm. The method mentioned here combines SFF with user-defined constraints in spectral absorption feature to extract more accurate target information from hyperspectral image. Two experiments are presented herein, in which three algorithms are used to obtain mineral information from hyperspectral data with different space resolution and SNR. Muscovite, calcite and chlorite etc. are extracted by general SFF, modified SFF and spectral angle mapping (SAM) respectively, and the result indicates that modified SFF algorithm is more effective in differentiating subtle spectral feature and obtaining accurate mineral information. The experiments also demonstrate that the algorithm mentioned here is validated in mineral information extraction.

Cardiac myosin activation: a potential therapeutic approach for systolic heart failure.

Decreased cardiac contractility is a central feature of systolic heart failure. Existing drugs increase cardiac contractility indirectly through signaling cascades but are limited by their mechanism-related adverse effects. To avoid these limitations, we previously developed omecamtiv mecarbil, a small-molecule, direct activator of cardiac myosin. Here, we show that it binds to the myosin catalytic domain and operates by an allosteric mechanism to increase the transition rate of myosin into the strongly actin-bound force-generating state. Paradoxically, it inhibits adenosine 5'-triphosphate turnover in the absence of actin, which suggests that it stabilizes an actin-bound conformation of myosin. In animal models, omecamtiv mecarbil increases cardiac function by increasing the duration of ejection without changing the rates of contraction. Cardiac myosin activation may provide a new therapeutic approach for systolic heart failure.

[Effects of human Livin gene down-regulation by RNA interference on xenograft of transplantation tumor induced by SPC-A1 in nude mice].

OBJECTIVE: To explore the in vivo inhibitory effect of Livin gene silencing by RNA interference on xenograft of lung adenocarcinoma SPC-A-1 cells in BALB/C nude mice. METHODS: Three different BALB/C nude mice models were established by subcutaneously inoculating differently treated SPC-A-1 cells into 3 nude mice groups: the blank control group was inoculated with blank SPC-A-1 cells, while the negative group was inoculated with cells transfected with lentivirus-delivered negative shRNA, the experimental group was inoculated with cells with lentivirus-delivered Livin shRNA. Then the growth of tumors was observed, and the volume and weight of the tumors were measured at different time points. The curve of tumor growth was then described, and the inhibition rate was calculated. Livin gene expression in the tumor tissues was determined by RT-PCR and Immunohistochemistry. Cell apoptosis of tumor tissues was detected by TUNEL. RESULTS: Slower tumor growth, smaller tumor volume and lighter tumor weight were observed in the experimental group as compared to the blank and negative groups (F = 70.509, P < 0.01; F = 12.821, P < 0.01). The inhibition rate of tumor volume was (59.5 ± 3.4)%, and the inhibition rate of tumor weight was (71.1 ± 5.6)%. Livinα mRNA and Livinß mRNA expressions in the experimental group were significantly lower than the 2 control groups [(37.2 ± 1.6)% versus (63.3 ± 3.8)%, (66.1 ± 2.6)%; (29.4 ± 1.1)% versus (53.2 ± 3.4)%, (52.3 ± 3.1)% (F(α) = 45.309, P < 0.01; F(ß) = 30.076, P < 0.01)]. Livin protein expression level was also significantly lower than the blank and the negative groups [(15.3 ± 2.8)% versus (51.3 ± 2.1)%, (52.5 ± 2.5)%, F = 78.92, P < 0.01]. The apoptosis rate in the experimental group was significantly higher than that in the 2 control groups [(35.4 ± 3.2)% versus (5.4 ± 1.3)%, (8.6 ± 1.5)%, F = 14.509, P < 0.01]. CONCLUSION: The lentivirus-delivered Livin shRNA was shown to inhibit the proliferation of transplantation tumor of lung carcinoma effectively, and Livin may be a target for gene therapy in lung cancer.

Preemptive conditioning of the swine heart by H11 kinase/Hsp22 provides cardiac protection through inducible nitric oxide synthase.

The second window of ischemic preconditioning (SWOP) provides maximal protection against ischemia through regulation of the inducible nitric oxide synthase (iNOS), yet its application is limited by the inconvenience of the preliminary ischemic stimulus required for prophylaxis. Overexpression of H11 kinase/Hsp22 (Hsp22) in a transgenic mouse model provides cardioprotection against ischemia that is equivalent to that conferred by SWOP. We hypothesized that short-term, prophylactic overexpression of Hsp22 would offer an alternative to SWOP in reducing ischemic damage through a nitric oxide (NO)-dependent mechanism. Adeno-mediated overexpression of Hsp22 was achieved in the area at risk of the left circumflex (Cx) coronary artery in chronically instrumented swine and compared with LacZ controls (n = 5/group). Hsp22-injected myocardium showed an average fourfold increase in Hsp22 protein expression compared with controls and a doubling in iNOS expression (both P < 0.05). Four days after ischemia-reperfusion, regional wall thickening was reduced by 58 ± 2% in the Hsp22 group vs. 82 ± 7% in the LacZ group, and Hsp22 reduced infarct size by 40% (both P < 0.05 vs. LacZ). Treatment with the NOS inhibitor N(G)-nitro-L-arginine (L-NNA) before ischemia suppressed the protection induced by Hsp22. In isolated cardiomyocytes, Hsp22 increased iNOS expression through the transcription factors NF-κB and STAT, the same effectors activated by SWOP, and reduced by 60% H(2)O(2)-mediated apoptosis, which was also abolished by NOS inhibitors. Therefore, short-term, prophylactic conditioning by Hsp22 provides NO-dependent cardioprotection that reproduces the signaling of SWOP, placing Hsp22 as a potential alternative for preemptive treatment of myocardial ischemia.

Primate models for cardiovascular drug research and development.

One of the primary impediments to successful drug R&D is the frequent failure of successfully translating positive results obtained in animal models to human disease. To a large degree, this discrepancy is secondary to the substantial biological differences between species. Non-human primate models have the advantage of significant physiological, metabolic, biochemical and genetic similarity to humans. Despite this advantage, there has been a relative paucity of non-human primate models used in the study of disease states that currently underlie the most common causes of morbidity and mortality, such as chronic myocardial ischemia leading to heart failure. This review describes a primate model of heart failure that closely mimics the cardiomyopathic process observed in humans. The primary advantage of this non-human primate model is that, unlike existing heart failure models, it allows for continuous study during progressive stages of heart failure, including myocardial ischemia, progressive left ventricular remodeling and end-stage congestive heart failure. In addition to this model of heart failure, other non-human primate models for cardiovascular drug R&D are also reviewed.

Molecular mechanisms mediating preconditioning following chronic ischemia differ from those in classical second window.

A major difference between experimental ischemic preconditioning (IPC), induced by brief ischemic episodes, and the clinical situation is that patients generally have repetitive episodes of ischemia. We used a swine model to examine differences in genes regulated by classical second-window IPC (SWOP) [two 10-min episodes of coronary artery occlusion (CAO) followed by 24 h reperfusion] compared with repetitive CAO/reperfusion (RCO), i.e., two 10-min CAO 12 h apart, and to repetitive coronary stenosis (RCS), six episodes of 90 min coronary stenosis 12 h apart (n = 5/group). All three models reduced infarct size by 60-85%, which was mediated by nitric oxide in SWOP but not in the other two models. We employed microarray analyses to discover additional molecular pathways intrinsic to models of repetitive ischemia and different from classical SWOP. There was an 85% homology in gene response between the RCO and RCS models, whereas SWOP was qualitatively different. Both RCO and RCS, but not SWOP, showed downregulation of genes encoding proteins involved in oxidative metabolism and upregulation of genes involved in protein synthesis, unfolded protein response, autophagy, heat shock response, protein secretion, and an activation of the NF-kappaB signaling pathway. Therefore, the regulated genes mediating IPC with repetitive ischemia differ radically from SWOP both quantitatively and qualitatively, showing that a repetitive pattern of ischemia, rather than the difference between no-flow vs. low-flow ischemia, dictates the genomic response of the heart. These findings illustrate new cardioprotective mechanisms developed by repetitive IPC, which are potentially more relevant to patients with chronic ischemic heart disease, who are subjected to repetitive episodes of ischemia.

Glucagon-like peptide-1 increases myocardial glucose uptake via p38alpha MAP kinase-mediated, nitric oxide-dependent mechanisms in conscious dogs with dilated cardiomyopathy.

BACKGROUND: We have shown that glucagon-like peptide-1 (GLP-1[7-36] amide) stimulates myocardial glucose uptake in dilated cardiomyopathy (DCM) independent of an insulinotropic effect. The cellular mechanisms of GLP-1-induced myocardial glucose uptake are unknown. METHODS AND RESULTS: Myocardial substrates and glucoregulatory hormones were measured in conscious, chronically instrumented dogs at control (n=6), DCM (n=9) and DCM after treatment with a 48-hour infusion of GLP-1 (7-36) amide (n=9) or vehicle (n=6). GLP-1 receptors and cellular pathways implicated in myocardial glucose uptake were measured in sarcolemmal membranes harvested from the 4 groups. GLP-1 stimulated myocardial glucose uptake (DCM: 20+/-7 nmol/min/g; DCM+GLP-1: 61+/-12 nmol/min/g; P=0.001) independent of increased plasma insulin levels. The GLP-1 receptors were upregulated in the sarcolemmal membranes (control: 98+/-2 density units; DCM: 256+/-58 density units; P=0.046) and were expressed in their activated (65 kDa) form in DCM. The GLP-1-induced increases in myocardial glucose uptake did not involve adenylyl cyclase or Akt activation but was associated with marked increases in p38alpha MAP kinase activity (DCM+vehicle: 97+/-22 pmol ATP/mg/min; DCM+GLP-1: 170+/-36 pmol ATP/mg/min; P=0.051), induction of nitric oxide synthase 2 (DCM+vehicle: 151+/-13 density units; DCM+GLP-1: 306+/-12 density units; P=0.001), and GLUT-1 translocation (DCM+vehicle: 21+/-3% membrane bound; DCM+GLP-1: 39+/-3% membrane bound; P=0.005). The effects of GLP-1 on myocardial glucose uptake were blocked by pretreatment with the p38alpha MAP kinase inhibitor or the nonspecific nitric oxide synthase inhibitor nitro-l-arginine. CONCLUSIONS: GLP-1 stimulates myocardial glucose uptake through a non-Akt-1-dependent mechanism by activating cellular pathways that have been identified in mediating chronic hibernation and the late phase of ischemic preconditioning.