Role of glucagon-like peptide-1 and its agonists on early prevention of cardiac remodeling in type 1 diabetic rat hearts

Glucagon-like peptide-1 (GLP-1) is an incretin hormone secreted from intestinal L cells upon nutrients ingestion, and is currently used for treating diabetes mellitus. It plays an important role in receptor modulation and cross talk with insulin at the coronary endothelium (CE) and cardiomyocytes (CM) in diabetic type 1 rat heart model. We studied the effects of insulin, GLP-1 analogues (exendin-4), and dipeptidyl peptidase-IV (DPP-IV) inhibitor on GLP-1 cardiac receptor modulation. The binding affinity of GLP-1 to its receptor on CE and CM was calculated using a rat heart perfusion model with [(125)I]-GLP-1(7-36). Tissue samples from the heart were used for immunostaining and Western blot analyses. GLP-1 systemic blood levels were measured using ELISA. GLP-1 binding affinity (τ) increased on the CE (0.33 ± 0.01 vs. 0.25 ± 0.01 min; p < 0.001) and decreased on the CM (0.29 ± 0.02 vs. 0.43 ± 0.02 min; p < 0.001) in the diabetic non-treated rats when compared to normal. There was normalization of τ back to baseline on the CE and CM levels with insulin and DPP-IV inhibitor treatment, respectively. Histological sections and immunofluorescence showed receptor up-regulation in diabetic rats with significant decrease and even normalization with the different treatment strategies. Systemic GLP-1 levels increased after 14 days of diabetes induction (10 ± 3.7 vs. 103 ± 58 pM; p = 0.0005). In conclusion, there is a significant GLP-1 receptor affinity modulation on the CE and CM levels in rats with diabetes type 1, and a cross talk with GLP-1 analogues in early prevention of cardiac remodeling.     

High throughput and rapid screening of marine protein hydrolysates enriched in peptides with angiotensin-I-converting enzyme inhibitory activity by capillary electrophoresis

Twelve kinds of marine protein materials, including fish, shrimp, seashell, algae and seafood wastes were selected for the hydrolysis using four different proteases. The IC(50) values for angiotensin-converting enzyme (ACE) inhibitory activity of 48 hydrolysates were rapidly determined by capillary electrophoresis (CE). The values ranged from 0.17 to 501.7mg/ml, and were affected by both the marine protein resources and the selected proteases. Hydrolysates of the lowest IC(50) values were from shrimp (Acetes chinensis), shark meat, mackerel bone, Polysiphonia urceolata and Spirulina platensis, indicating these five kinds of marine food proteins contained beneficial materials for the production of ACE inhibitory peptides by proteolysis. The hydrolysates obtained using proteases Protamex and SM98011 had lower IC(50) values, showing these two proteases were superior to others. The CE method achieved the same sensitivity as the high performance liquid chromatography (HPLC) method. However, the CE method was faster and, as a result, more economical. Therefore, CE had potential for rapid screening of marine protein hydrolysates enriched in ACE inhibitory peptides.     

右心声学造影联合血清cTnI、NT-proBNP对心源性脑梗死的预测价值

摘要 目的：探讨右心声学造影联合血清心肌肌钙蛋白I（cTnI）、N-末端脑利钠肽前体（NT-proBNP）对心源性脑梗死（CE）的预测价值。方法：选择2020年7月至2023年6月湖南中医药高等专科学校附属第一医院收治的急性脑梗死患者128例,根据是否发生CE分为CE组（n=31）和非CE组（n=97）。两组均行右心声学造影检查,检测两组血清cTnI、NT-proBNP水平,比较两组右心声学造影参数及血清cTnI、NT-proBNP水平。受试者工作特征（ROC）曲线分析右心声学造影联合血清cTnI、NT-proBNP对CE的预测价值。结果：右心声学造影显示CE组卵圆孔未闭阳性率、右向左分流分级（1级+2级+3级）构成比、卵圆孔长径均显著高于非CE组（P<0.05）。CE组卵圆孔未闭患者活动性房间隔构成比显著高于非CE组卵圆孔未闭患者（P<0.05）。CE组血清cTnI、NT-proBNP水平显著高于非CE组。ROC曲线分析结果显示,卵圆孔未闭、右向左分流分级1级+2级+3级、卵圆孔长径、活动性房间隔、cTnI、NT-proBNP对CE具有一定的预测价值,其中联合检验对CE的预测效能最高,曲线下面积（AUC）为0.867（0.812～0.928）。结论：右心声学造影联合血清cTnI、NT-proBNP检查可用于CE的预测。     

Some proposals in cardiac muscle mechanics and energetics

Based on A. V. Hill's three-component model, mechanical properties of the contractile element (CE), such as velocity and tension, were determined as muscle shortening and loads in quick-release or afterloaded isotonic contraction. The method is applicable for studying cardiac mechanics, to obtain force-velocity data of the same CE length at varous afterloads. Analysis of the energetics of cardiac muscle was based on simulation studies of cardiac mechanics (Wong 1971, 1972). By proper derivation, the conventional contractile element work (CEW) was found to be a minor energy determinant. The tension-time integral and tension-independent heat (Ricchiuti and Gibbs, 1965) represent energy utilization for activation and maintenance of tension, the primary energy determinant.     

Chicken extract affects colostrum protein compositions in lactating women

This study investigated the effect of supplementation with chicken extract on plasma and colostrum protein compositions in lactating women. Thirty healthy pregnant women were evenly divided into the control (n = 15) or chicken extract (CE) group (n = 15). The CE group was given one bottle (70 mL/bottle) of chicken extract three times a day to provide 18 g protein from the 37th week pregnancy to 3 days postpartum. All women in the CE group consumed chicken extract at least for 2 weeks (18 +/- 5 days). High protein supplement was restricted in the control group. Blood samples were collected during the 37th week pregnancy and 3-day postpartum, and milk was collected during 3-day postpartum. The results showed that plasma total protein was significantly lower by 14% in the CE group compared with that in the control group during 3-day postpartum. Plasma epidermal growth factor (EGF) significantly elevated by 236% during 3-day postpartum compared with those during the 37th week pregnancy in the CE group. The levels of lactoferrin, EGF, and transforming growth factor-beta2 (TGF-beta2) in colostrum significantly increased by 34%, 62%, and 196%, respectively, in the CE group compared with those in the control group. However, the levels of total protein, casein, lactalbumin, and secretory immunoglobulin A in colostrum did not significantly differ between two groups. Therefore, supplementation with chicken extract increased colostrum levels of lactoferrin, EGF, and TGF-beta2, which are important for the growth and immune functions of the infants, in lactating women.     

Mass spectrometric proteome analysis for profiling temperature-dependent changes of protein expression in wild-type Caenorhabditis elegans

We investigated the effect of cultivation temperatures on the protein expression levels in the fourth larval stage of the postembryonic development of wild-type Caenorhabditis elegans by mass spectrometric proteome analysis. From the 64 protein spots that were investigated, 5 spots were found reproducibly differently expressed when proteome maps derived from animals kept at 15 degrees C and at 25 degrees C, respectively, were compared. Spots of heat shock proteins HSP 70 (CE18679 or CE09682) and HSP 16 (CE14249) were present only in gels from protein extracts when worms were grown at 15 degrees C. Spots of two metabolic enzymes, the isocitrate dehydrogenase (CE10345) and the aspartic proteinase (CE21681) were detected only in cultures grown at the lower temperature as well. A protein with still unknown function (CE05036) was present only in gels from worm samples grown at 25 degrees C. We show for the first time by proteome analyses that cultivation of worms at the lowest temperature of the known physiological range (15 degrees C) already triggers a (weak) stress response in wild-type animals. This work led to the identification of "internal control proteins" in the wild-type strain for further characterization of temperature-sensitive strains using a proteomics approach.     

Identification of a Tetrahydroquinoline Analog as a Pharmacological Inhibitor of the cAMP-binding Protein Epac

The cAMP-binding protein Epac is a therapeutic target for the treatment of various diseases such as cardiac hypertrophy and tumor invasion. This points out the importance to develop Epac inhibitors to better understand the involvement of these cAMP sensors in physiology and pathophysiology. Here, we have developed a functional fluorescence-based high-throughput assay with a Z′ value around 0.7 for screening Epac-specific antagonists. We identified an Epac1 inhibitor compound named CE3F4 that blocked Epac1 guanine nucleotide exchange activity toward its effector Rap1 both in cell-free systems and in intact cells. CE3F4 is a tetrahydroquinoline analog that fails to influence protein kinase A holoenzyme activity. CE3F4 inhibited neither the interaction of Rap1 with Epac1 nor directly the GDP exchange on Rap1. The kinetics of inhibition by CE3F4 indicated that this compound did not compete for binding of agonists to Epac1 and suggested an uncompetitive inhibition mechanism with respect to Epac1 agonists. A structure-activity study showed that the formyl group on position 1 and the bromine atom on position 5 of the tetrahydroquinoline skeleton were important for CE3F4 to exert its inhibitory activity. Finally, CE3F4 inhibited Rap1 activation in living cultured cells, following Epac activation by either 8-(4-chlorophenylthio)-2′-O-methyl-cAMP, an Epac-selective agonist, or isoprenaline, a non-selective β-adrenergic receptor agonist. Our study shows that CE3F4 and related compounds may serve as a basis for the development of new therapeutic drugs.     

Postoperative changes in serum cytokines profile and nitric oxide levels in patients with cystic echinococcosis

The aim of the present study was to examine serum cytokines and nitric oxide (NO) levels in patients with cystic echinococcosis (CE). 28 patients with CE were studied and all underwent surgery. Serum levels of tumour necrosis factor-alpha (TNF-alpha), interleukin IL-1beta, receptor of soluble IL-2R (sIL-2R), IL-6, IL-8, nitrate/nitrite, and C-reactive protein (CRP) were determined before and after induction of treatment. Data were compared with those obtained from 28 healthy volunteers. IL-6 was elevated in all CE patients (100%). IL-8 was increased in 11/28 (39.3%). Increased levels of IL-2R and TNF-alpha were found in a limited number of them particularly those showing cysts in the central area of the liver (5/28, 6/28). IL-1beta level was not elevated in any patient except in secondary severe CE. CRP and nitrate/nitrite levels were also increased. A positive correlation between CRP and IL-6 (r = 0.74; p < 0.001) was found confirming the link between inflammation due to CE and activation of monocytes. All patients completely recovered and the levels of the studied parameters reverted to normal levels except one patient in whom severe recurrent disease occurred two years after the first operation. These results suggest that there are different immunoregulatory events and cytokines response during CE and may be in part related to slight monocytosis and in part to Th2 activation. IL-6, NO and CRP were unambiguously involved in the host parasite interaction and therefore may be useful markers in monitoring CE management and evaluating surgical stress.     

Management and outcome of cardiac and endovascular cystic echinococcosis

Background

Cystic echinococcosis (CE) can affect the heart and the vena cava but few cases are reported.

Methods

A retrospective case series of 11 patients with cardiac and/or endovascular CE, followed-up over a period of 15 years (1995–2009) is reported.

Results

Main clinical manifestations included thoracic pain or dyspnea, although 2 patients were asymptomatic. Cysts were located mostly in the right atrium and inferior vena cava. Nine patients were previously diagnosed with disseminated CE. Echocardiography was the diagnostic method of choice, although serology, electrocardiogram, chest X-ray, computed tomography/magnetic resonance imaging and histology aided with diagnosis and follow-up. Nine patients underwent cardiac surgery and nine received long-term antiparasitic treatment for a median duration of 25 months (range 4–93 months). One patient died intra-operatively due to cyst rupture and endovascular dissemination. Two patients died 10 and 14 years after diagnosis, due to pulmonary embolism (PE) and cardiac failure, respectively. One patient was lost to follow-up. Patients who had cardiac involvement exclusively did not have complications after surgery and were considered cured. There was only one recurrence requiring a second operation. Patients with vena cava involvement developed PEs and presented multiple complications.

Conclusions

Cardiovascular CE is associated with a high risk of potentially lethal complications. Clinical manifestations and complications vary according to cyst location. Isolated cardiac CE may be cured after surgery, while endovascular extracardiac involvement is associated with severe chronic complications. CE should be included in the differential diagnosis of cardiovascular disease in patients from endemic areas.     

Dark proteins: effect of inclusion body formation on quantification of protein expression

Plasmid-borne gene expression systems have found wide application in the emerging fields of systems biology and synthetic biology, where plasmids are used to implement simple network architectures, either to test systems biology hypotheses about issues such as gene expression noise or as a means of exerting artificial control over a cell's dynamics. In both these cases, fluorescent proteins are commonly applied as a means of monitoring the expression of genes in the living cell, and efforts have been made to quantify protein expression levels through fluorescence intensity calibration and by monitoring the partitioning of proteins among the two daughter cells after division; such quantification is important in formulating the predictive models desired in systems and synthetic biology research. A potential pitfall of using plasmid-based gene expression systems is that the high protein levels associated with expression from plasmids can lead to the formation of inclusion bodies, insoluble aggregates of misfolded, nonfunctional proteins that will not generate fluorescence output; proteins caught in these inclusion bodies are thus "dark" to fluorescence-based detection methods. If significant numbers of proteins are incorporated into inclusion bodies rather than becoming biologically active, quantitative results obtained by fluorescent measurements will be skewed; we investigate this phenomenon here. We have created two plasmid constructs with differing average copy numbers, both incorporating an unregulated promoter (P(LtetO-1) in the absence of TetR) expressing the GFP derivative enhanced green fluorescent protein (EGFP), and inserted them into Escherichia coli bacterial cells (a common model organism for work on the dynamics of prokaryotic gene expression). We extracted the inclusion bodies, denatured them, and refolded them to render them active, obtaining a measurement of the average number of EGFP per cell locked into these aggregates; at the same time, we used calibrated fluorescent intensity measurements to determine the average number of active EGFP present per cell. Both measurements were carried out as a function of cellular doubling time, over a range of 45-75 min. We found that the ratio of inclusion body EGFP to active EGFP varied strongly as a function of the cellular growth rate, and that the number of "dark" proteins in the aggregates could in fact be substantial, reaching ratios as high as approximately five proteins locked into inclusion bodies for every active protein (at the fastest growth rate), and dropping to ratios well below 1 (for the slowest growth rate). Our results suggest that efforts to compare computational models to protein numbers derived from fluorescence measurements should take inclusion body loss into account, especially when working with rapidly growing cells.     

Physical conditioning modulates rat cardiac vascular endothelial growth factor gene expression in nitric oxide-deficient hypertension

Many individuals with cardiac diseases undergo periodic physical conditioning with or without medication to improve cardiovascular health. Therefore, this study investigated the interaction of physical training and chronic nitric oxide synthase (NOS) inhibitor (nitro-L-arginine methyl ester, L-NAME) treatment on blood pressure (BP), cardiac vascular endothelial factor (VEGF) gene expression, and nitric oxide (NO) systems in rats. Fisher 344 rats were divided into four groups and treated as follows: (1) sedentary control, (2) exercise training (ET) for 8 weeks, (3) L-NAME (10mg/kg, s.c. for 8 weeks), and (4) ET+L-NAME. BP was monitored with tail-cuff method. The animals were sacrificed 24h after last treatments and hearts were isolated and analyzed. Physical conditioning significantly increased respiratory exchange ratio, cardiac NO levels, NOS activity, endothelial eNOS, and inducible iNOS protein expression as well as VEGF gene expression. Training also caused depletion of cardiac malondialdehyde (MDA) levels indicating the beneficial effects of the training. Chronic L-NAME administration resulted in a depletion of cardiac NO level, NOS activity, and eNOS, nNOS, and iNOS protein expressions, as well as VEGF gene expression (2-fold increase in VEGF mRNA). Chronic L-NAME administration also enhanced cardiac MDA levels indicating cardiac oxidative injury. These biochemical changes were accompanied by increases in BP after L-NAME administration. Interaction of training and NOS inhibitor treatment resulted in normalization of BP and up-regulation of cardiac VEGF gene expression. The data suggest that physical conditioning attenuated the oxidative injury caused by chronic NOS inhibition by up-regulating the cardiac VEGF and NO levels and lowering the BP in rats.     

Quantification of fluorescence in thick specimens, with an application to cyclin B-GFP expression in starfish oocytes

BACKGROUND INFORMATION: Fluorescence imaging of living cells is widely used in cell biology. It is now being extended to thick specimens such as large cells or tissues where it is important to establish methods for obtaining quantitative fluorescence data due to the increasing importance of computational and systems biology approaches. RESULTS: Fluorescent solutions were used as a calibration standard for determining cellular fluorescence concentrations from z series image sequences. The accuracy of the measurements was evaluated using quantitatively injected cells. Different fluorescence attenuation rates of the cytoplasm and nucleoplasm were documented, and autofluorescence levels were determined. This method was used to characterize the effect of cyclin B overexpression on cell-cycle timing in starfish oocytes. The time interval between application of maturation hormone and germinal vesicle breakdown decreased with increasing cyclin B-GFP (green fluorescent protein) concentration to a level of 100-300 nM, beyond which there was no effect. CONCLUSIONS: Conditions for determining fluorescent probe concentrations in large cells or multicellular tissues were established, which will facilitate the collection of data for quantitative studies. This method was used to characterize the effect of cyclin B-GFP expression levels on cell-cycle timing in starfish oocytes.     

Oxidative injury due to chronic nitric oxide synthase inhibition in rat: effect of regular exercise on the heart

Many individuals with cardiac diseases undergo periodic physical conditioning with or without medication. Therefore, this study investigated the interaction of physical training and chronic nitric oxide synthase (NOS) inhibitor (nitro-L-arginine methyl ester, L-NAME) treatment on blood pressure (BP), heart rate (HR) and cardiac oxidant/antioxidant systems in rats. Fisher 344 rats were divided into four groups and treated as follows: (1) sedentary control (SC), (2) exercise training (ET) for 8 weeks, (3) L-NAME (10 mg/kg, s.c. for 8 weeks) and (4) ET+L-NAME. BP and HR were monitored with tail-cuff method. The animals were sacrificed 24 h after last treatments and hearts were isolated and analyzed. Physical conditioning significantly increased respiratory exchange ratio (RER), cardiac nitric oxide (NO) levels, NOS activity and endothelial (eNOS) and inducible (iNOS) protein expression. Training significantly enhanced cardiac glutathione (GSH) levels, GSH/GSSG ratio and up-regulation of cardiac copper/zinc-superoxide dismutase (CuZn-SOD), manganese (Mn)-SOD, catalase (CAT), glutathione peroxidase (GSH-Px) activity and protein expression. Training also caused depletion of cardiac malondialdehyde (MDA) and protein carbonyls. Chronic L-NAME administration resulted in depletion of cardiac NO level, NOS activity, eNOS, nNOS and iNOS protein expression, GSH/GSSG ratio and down-regulation of cardiac CuZn-SOD, Mn-SOD, CAT, GSH-PX, glutathione-S-transferase (GST) activity and protein expression. Chronic L-NAME administration enhanced cardiac xanthine oxidase (XO) activity, MDA levels and protein carbonyls. These biochemical changes were accompanied by increases in BP and HR after L-NAME administration. Interaction of training and NOS inhibitor treatment resulted in normalization of BP, HR and up-regulation of cardiac antioxidant defense system. The data suggest that physical conditioning attenuated the oxidative injury caused by chronic NOS inhibition by up-regulating the cardiac antioxidant defense system and lowering the BP and HR in rats.     

Cardioselective dominant-negative thyroid hormone receptor (Delta337T) modulates myocardial metabolism and contractile efficiency

Dominant-negative thyroid hormone receptors (TRs) show elevated expression relative to ligand-binding TRs during cardiac hypertrophy. We tested the hypothesis that overexpression of a dominant-negative TR alters cardiac metabolism and contractile efficiency (CE). We used mice expressing the cardioselective dominant-negative TRbeta(1) mutation Delta337T. Isolated working Delta337T hearts and nontransgenic control (Con) hearts were perfused with (13)C-labeled free fatty acids (FFA), acetoacetate (ACAC), lactate, and glucose at physiological concentrations for 30 min. (13)C NMR spectroscopy and isotopomer analyses were used to determine substrate flux and fractional contributions (Fc) of acetyl-CoA to the citric acid cycle (CAC). Delta337T hearts exhibited rate depression but higher developed pressure and CE, defined as work per oxygen consumption (MVo(2)). Unlabeled substrate Fc from endogenous sources was higher in Delta337T, but ACAC Fc was lower. Fluxes through CAC, lactate, ACAC, and FFA were reduced in Delta337T. CE and Fc differences were reversed by pacing Delta337T to Con rates, accompanied by an increase in FFA Fc. Delta337T hearts lacked the ability to increase MVo(2). Decreases in protein expression for glucose transporter-4 and hexokinase-2 and increases in pyruvate dehydrogenase kinase-2 and -4 suggest that these hearts are unable to increase carbohydrate oxidation in response to stress. These data show that Delta337T alters the metabolic phenotype in murine heart by reducing substrate flux for multiple pathways. Some of these changes are heart rate dependent, indicating that the substrate shift may represent an accommodation to altered contractile protein kinetics, which can be disrupted by pacing stress.     

Role of the season and of the nutritonnal state on the distribution of tissular fatty acids in the hibernating dormouse (Eliomys quercinus L.)]

Seasonal changes were observed in fatty acid composition of plasma, liver and cardiac muscle. During hibernation unsaturated fatty acids levels increase in plasma cholesterol esters (CE), glycerides (GL) and phospholipids. After spring arousal, the oleic acid content decreases in total fatty acids of liver and cardiac muscle. In summer fasting induces lipid changes similar to that occuring in natural hibernation. Desaturation observed in winter can be explained by the accumulation of unsaturated GL and CE in the tissues.     

New analysis technique for multistability detection

Systems with counter-clockwise input-output (I-O) dynamics were recently introduced in order to study the convergence of positive feedback loops (possibly to many different equilibrium states). The author shows how this notion can be used to perform bifurcation analysis and globally predict multistability of a closed-loop feedback interconnection just by using the knowledge of steady-state I-O responses of the systems. To illustrate the theory, this method is then applied to a recently published model of mitogen activated protein kinase (MAPK) cascade. Furthermore, some examples (mainly motivated by molecular biology) of systems that enjoy the property are presented and discussed.     

Hand-carried ultrasound performed at bedside in cardiology inpatient setting – a comparative study with comprehensive echocardiography

Background

Hand-carried ultrasound (HCU) devices have been demonstrated to improve the diagnosis of cardiac diseases over physical examination, and have the potential to broaden the versatility in ultrasound application. The role of these devices in the assessment of hospitalized patients is not completely established. In this study we sought to perform a direct comparison between bedside evaluation using HCU and comprehensive echocardiography (CE), in cardiology inpatient setting.

Methods

We studied 44 consecutive patients (mean age 54 ± 18 years, 25 men) who underwent bedside echocardiography using HCU and CE. HCU was performed by a cardiologist with level-2 training in the performance and interpretation of echocardiography, using two-dimensional imaging, color Doppler, and simple calliper measurements. CE was performed by an experienced echocardiographer (level-3 training) and considered as the gold standard.

Results

There were no significant differences in cardiac chamber dimensions and left ventricular ejection fraction determined by the two techniques. The agreement between HCU and CE for the detection of segmental wall motion abnormalities was 83% (Kappa = 0.58). There was good agreement for detecting significant mitral valve regurgitation (Kappa = 0.85), aortic regurgitation (kappa = 0.89), and tricuspid regurgitation (Kappa = 0.74). A complete evaluation of patients with stenotic and prosthetic dysfunctional valves, as well as pulmonary hypertension, was not possible using HCU due to its technical limitations in determining hemodynamic parameters.

Conclusion

Bedside evaluation using HCU is helpful for assessing cardiac chamber dimensions, left ventricular global and segmental function, and significant valvular regurgitation. However, it has limitations regarding hemodynamic assessment, an important issue in the cardiology inpatient setting.     

VIP down-regulates the inflammatory potential and promotes survival of dying (neural crest-derived) corneal endothelial cells ex vivo: necrosis to apoptosis switch and up-regulation of Bcl-2 and N-cadherin

The neuropeptide vasoactive intestinal peptide (VIP) is anti-inflammatory and protective in the immune and nervous systems, respectively. This study demonstrated in corneal endothelial (CE) cells injured by severe oxidative stress (1.4 mM H₂O₂) in bovine corneal organ cultures that VIP pre-treatment (0, 10⁻¹⁰, 10⁻⁸, and 10⁻⁶ M; 15 min), in a VIP concentration-dependent manner, switched the inflammation-causing necrosis to inflammation-neutral apoptosis (showing annexin V-binding, chromatin condensation, and DNA fragmentation) and upheld ATP levels in a VIP antagonist (SN)VIPhyb-sensitive manner, while up-regulated mRNA levels of the anti-apoptotic Bcl-2 and the differentiation marker N-cadherin in a kinase A inhibitor-sensitive manner. As a result, VIP, in a concentration-dependent and VIP antagonist-sensitive manners, promoted long-term CE cell survival. ATP levels, a determining factor in the choice of apoptosis versus necrosis, measured after VIP pre-treatment and 0.5 min post-H₂O₂ were 39.6 ± 3.3, 50.8 ± 6.2, 60.1 ± 4.8, and 53.6 ± 5.3 pmoles/μg protein (mean ± SEM), respectively ( p  < 0.05, anova ). VIP treatment alone concentration-dependently increased levels of N-cadherin ( Koh et al. 2008 ), the phosphorylated cAMP-responsive-element binding protein and Bcl-2, while10⁻⁸ M VIP, in a VIP antagonist (SN)VIPhyb-sensitive manner, increased ATP level by 38% ( p  < 0.02) and decreased glycogen level by 32% ( p  < 0.02). VPAC1 (not VPAC2) receptor was expressed in CE cells. Thus, CE cell VIP/VPAC1 signaling is both anti-inflammatory and protective in the corneal endothelium.