The Melanocortin MC5R as a New Target for Treatment of High Glucose-Induced Hypertrophy of the Cardiac H9c2 Cells.

The study explored the anti-hypertrophic effect of the melanocortin MC5R stimulation in H9c2 cardiac myocytes exposed to high glucose. This has been done by using α-MSH and selective MC5R agonists and assessing the expression of GLUT4 and GLUT1 transporters, miR-133 and urotensin receptor levels as a marker of cardiac hypertrophy. The study shows for the first time an up-regulation of MC5R expression levels in H9c2 cardiomyocytes exposed to high glucose medium (33 mM D-glucose) for 48 h, compared to cells grown in normal glucose medium (5.5 mM D-glucose). Moreover, H9c2 cells exposed to high glucose showed a significant reduction in cell viability (-40%), a significant increase in total protein per cell number (+109%), and an increase of the urotensin receptor expression levels as an evidence of cells hypertrophy. The pharmacological stimulation of MC5R with α-MSH (90 pM)of the high glucose exposed H9c2 cells increased the cell survival (+50,8%) and reduced the total protein per cell number (-28,2%) with respect to high glucose alone, confirming a reduction of the hypertrophic state as per cell area measurement. Similarly, PG-901 (selective agonist, 10-10 M) significantly increased cell viability (+61,0 %) and reduced total protein per cell number (-40,2%), compared to cells exposed to high glucose alone. Interestingly, the MC5R agonist reduced the GLUT1/GLUT4 glucose transporters ratio on the cell membranes exhibited by the hypertrophic H9c2 cells and increased the intracellular PI3K activity, mediated by a decrease of the levels of the miRNA miR-133a. The beneficial effects of MC5R agonism on the cardiac hypertrophy caused by high glucose was also observed also by echocardiographic evaluations of rats made diabetics with streptozotocin (65 mg/kg i.p.). Therefore, the melanocortin MC5R could be a new target for the treatment of high glucose-induced hypertrophy of the cardiac H9c2 cells.

Inhibition of aldose-reductase-2 by a benzofuroxane derivative bf-5m increases the expression of kcne1, kcnq1 in high glucose cultured H9c2 cardiac cells and sudden cardiac death.

Long QT syndrome (LQTS) is characterized by prolonged QT interval, leading to sudden cardiac death. Hyperglycemia is an important risk factor for LQTS, inhibiting the cardiac rapid component delayed rectifier K+ current (Iks), responsible for QT interval. We previously showed that the new ALR2 inhibitor BF-5m supplies cardioprotection from QT prolongation induced by high glucose concentration in the medium, reducing QT interval prolongation and preserving morphology. Here we investigated the effects of BF-5m on cell cytotoxicity and viability in H9c2 cells, and on cellular potassium ion channels expression. H9c2 cells were grown in medium with high glucose and high glucose plus the BF-5m by assessing the cytotoxic effects and the cell survival rate. In addition, KCNE1 and KCNQ1 expression in plasma and mitochondrial membranes were monitored. Also, the expression levels of miR-1 proved to suppress KCNQ1 and KCNE1, were analyzed. BF-5m treatment reduced the cytotoxic effects of high glucose on H9c2 cells by increasing cell survival rate and improving H9c2 morphology. Plasmatic KCNE1 and KCNQ1 expression levels were restored by BF-5m in H9c2 exposed to high glucose, down-regulating miR-1. These results suggest that BF-5m exerts cardioprotection from high glucose in rat heart ventricle H9c2 cells exposed to high glucose.

Intraperitoneal Administration of Oxygen/Ozone to Rats Reduces the Pancreatic Damage Induced by Streptozotocin.

Background: The rat model of streptozotocin (STZ)-induced pancreatic damage was used to examine whether a systemic oxygen/ozone mixture could be beneficial for the pancreas by reducing the machinery of the local detrimental mediators released by STZ. Results: The results showed that oxygen/ozone administration (150 µg/Kg i.p.) for ten days in STZ rats increased the endogenous glutathione-s-transferase (GST) enzyme and nuclear factor-erythroid 2-related factor 2 (Nrf2) into the pancreatic tissue, together with reduction of 4-hydroxynonenal (4-HNE) and PARP-1 compared to STZ rats receiving O2 only. Interestingly, these changes resulted in higher levels of serum insulin and leptin, and pancreatic glucagon immunostaining. Consequently, glucose metabolism improved as evidenced by the monitoring of glycemia throughout. Conclusions: This study provides evidence that systemic administration of oxygen/ozone reduces the machinery of detrimental mediators released by STZ into the pancreas with less local damage and better functionality.

Characterizing the anti-inflammatory and tissue protective actions of a novel Annexin A1 peptide.

Inflammation in now appreciated to be at the centre of may diseases that affect Western civilization. Current therapeutics for managing these conditions may interfere with the host response leading to immune suppression. We recently developed an annexin (Anx) A1-derived peptide, coined CR-AnxA12-50, which displays potent pro-resolving and tissue protective actions. Herein, we designed a novel peptide using CR-AnxA12-50 as a template that was significantly more resistant to neutrophil-mediated degradation. This peptide, termed CR-AnxA12-48, retained high affinity and specificity to the pro-resolving Lipoxin A4 receptor (ALX) with an IC50 of ~20nM. CR-AnxA12-48 dose dependently (100fM-10nM) promoted the efferocytosis of apoptotic neutrophils, an action that was mediated by the murine orthologue of human ALX. The neutrophil-directed actions were also retained with human primary cells were CR-AnxA12-48 reduced human neutrophil recruitment to activated endothelial cells at concentrations as low as 100 pM. This protective action was mediated by human ALX, since incubation of neutrophils with an anti-ALX antibody reversed this anti-inflammatory actions of CR-AnxA12-48. Administration of this peptide to mice during dermal inflammation led to a significant and dose dependent decrease in neutrophil recruitment. This reduction in neutrophil numbers was more pronounced than that displayed by the parent peptide CR-AnxA12-50. CR-AnxA12-48 was also cardioprotecitve reducing infarct size and systemic chemokine (C-C motif) ligand 5 concentration following ischemia reperfusion injury. These findings identify CR-AnxA12-48 as a new ALX agonist that regulates phagocyte responses and displays tissue-protective actions.

High Levels of Serum Ubiquitin and Proteasome in a Case of HLA-B27 Uveitis.

In this paper, the authors describe a case of high serum levels of ubiquitin and proteasome in a woman under an acute attack of autoimmune uveitis. The woman was 52 years old, diagnosed as positive for the Human leukocyte antigen-B27 gene, and came to our observation in January 2013 claiming a severe uveitis attack that involved the right eye. During the acute attack of uveitis, this woman had normal serum biochemical parameters but higher levels of serum ubiquitin and proteasome 20S subunit, with respect to a healthy volunteer matched for age and sex. These levels correlated well with the clinical score attributed to uveitis. After the patient was admitted to therapy, she received oral prednisone in a de-escalation protocol (doses from 50 to 5 mg/day) for four weeks. Following this therapy, she had an expected reduction of clinical signs and score for uveitis, but concomitantly she had a reduction of the serum levels of ubiquitin, poliubiquitinated proteins (MAb-FK1) and proteasome 20S activity. Therefore, a role for ubiquitin and proteasome in the development of human autoimmune uveitis has been hypothesized.

Melanocortin receptor agonists MCR1-5 protect photoreceptors from high-glucose damage and restore antioxidant enzymes in primary retinal cell culture.

Retinal photoreceptors are particularly vulnerable to local high-glucose concentrations. Oxidative stress is a risk factor for diabetic retinopathy development. Melanocortin receptors represent a family of G-protein-coupled receptors classified in five subtypes and are expressed in retina. Our previous data indicate that subtypes 1 and 5 receptor agonists exert a protective role on experimental diabetic retinopathy. This study focuses on their role in primary retinal cell cultures in high-glucose concentrations. After eye enucleation from wild-type male C57BL/6 mice, retinal cells were isolated, plated in high-glucose concentration and treated with melanocortin receptors 1 and 5 agonists and antagonists. Immunocytochemical and biochemical analysis showed that treatment with melanocortin receptors 1 and 5 agonists reduced anti-inflammatory cytokines and chemokines and enhanced manganese superoxide dismutase and glutathione peroxidase levels, preserving photoreceptor integrity. According with these evidences, we propose a major role of melanocortin receptors 1 and 5 on primary retinal cell response against high glucose or oxidative insults.

Circulating microRNA changes in heart failure patients treated with cardiac resynchronization therapy: responders vs. non-responders.

AIMS: MicroRNAs (miRNAs) play an important role in the pathogenesis of structural alterations of the failing heart through their ability to regulate negatively the expression levels of genes that govern the process of adaptive and maladaptive cardiac remodelling. We studied whether LV reverse remodelling after CRT was associated with changes of circulating miRNAs in patients with heart failure (HF) and dyssynchrony. METHODS AND RESULTS: A prospective, non-randomized self-control trial was performed in 81 patients with HF eligible for CRT. At baseline, to select the HF miRNA profile, we evaluated the expression of 84 miRNAs (implicated in the pathogenesis of structural alterations of the failing heart) in three groups of patients: healthy subjects (healthy group, n = 15); patients with HF (HF group, n = 81); and patients without HF matched for age, sex, and concomitant disease with HF patients (control group, n = 60). At 12 months, the selected miRNA profile was evaluated in plasma from responder (n = 55) and non-responder HF patients (n = 26) to CRT. In the test cohort, the HF patients were characterized by lower expression of 48 miRNAs (all P < 0.04) as compared with healthy subjects. In the validation cohort, the HF patients were characterized by lower expression of 24 miRNAs (all P < 0.03) as compared with control patients. At 12 months, 55 patients (68%) were considered responders and 26 non-responders to CRT (32%). Responders showed an increase in expression of 19 miRNAs (all P < 0.03) compared with baseline expression, whereas in the non-responders we observed an increase of six miRNAs (all P < 0.05) compared with baseline expression. At follow-up, miRNAs were differentially expressed between responders and non-responders. The responders were characterized by higher expression of five miRNAs (miRNA-26b-5p, miRNA-145-5p, miRNA-92a-3p, miRNA-30e-5p, and miRNA-29a-3p; P < 0.01 for all) as compared with non-responders. CONCLUSIONS: In responders, reverse remodelling is associated with favourable changes in miRNAs that regulate cardiac fibrosis, apoptosis, and hypertrophy.

Proresolving and tissue-protective actions of annexin A1-based cleavage-resistant peptides are mediated by formyl peptide receptor 2/lipoxin A4 receptor.

Endogenous mechanisms regulating the host response during inflammation resolution are critical in ensuring disposal of noxious stimuli and return to homeostasis. In this article, we engineered novel Annexin A1 (AnxA1)-based peptides, AnxA1(2-50), that displayed specific binding to the AnxA1 receptor (formyl peptide receptor 2/Lipoxin A4 receptor [FPR2/ALX]; IC50 ∼4 nM). Intravenous administration of AnxA1(2-50) markedly reduced (>60%) leukocyte adhesion to postcapillary venules in wild type and Fpr1(-/-), but not Fpr2/Alx(-/-), mice. Generation of a metabolically stable form of this peptide (CR-AnxA1(2-50)), engineered by substituting a cleavage site shared by human proteinase 3 and neutrophil elastase, yielded an agonist that was resistant to neutrophil-mediated cleavage and displayed enhanced proresolving actions: accelerated resolution of self-limited inflammation and enhanced macrophage efferocytosis after sterile injury, when compared with AnxA1(2-50). These actions were retained with human primary leukocytes where CR-AnxA1(2-50) decreased neutrophil-endothelial interactions (∼25-45%), and stimulated neutrophil apoptosis and macrophage efferocytosis (∼45%). In murine cardiac ischemia/reperfusion injury, CR-AnxA1(2-50) elicited tissue-protective actions reducing infarct size (∼60%) and incidence of 24-h death. These results identify AnxA1(2-50) and CR-AnxA1(2-50) as FPR2/ALX agonists that harness the proresolving actions of AnxA1, and thus may represent therapeutic tools for treatment of inflammatory conditions.

Effects of PPARs agonists on cardiac metabolism in littermate and cardiomyocyte-specific PPAR-γ-knockout (CM-PGKO) mice.

Understanding the molecular regulatory mechanisms controlling for myocardial lipid metabolism is of critical importance for the development of new therapeutic strategies for heart diseases. The role of PPARγ and thiazolidinediones in regulation of myocardial lipid metabolism is controversial. The aim of our study was to assess the role of PPARγ on myocardial lipid metabolism and function and differentiate local/from systemic actions of PPARs agonists using cardiomyocyte-specific PPARγ -knockout (CM-PGKO) mice. To this aim, the effect of PPARγ, PPARγ/PPARα and PPARα agonists on cardiac function, intra-myocyte lipid accumulation and myocardial expression profile of genes and proteins, affecting lipid oxidation, uptake, synthesis, and storage (CD36, CPT1MIIA, AOX, FAS, SREBP1-c and ADPR) was evaluated in cardiomyocyte-specific PPARγ-knockout (CM-PGKO) and littermate control mice undergoing standard and high fat diet (HFD). At baseline, protein levels and mRNA expression of genes involved in lipid uptake, oxidation, synthesis, and accumulation of CM-PGKO mice were not significantly different from those of their littermate controls. At baseline, no difference in myocardial lipid content was found between CM-PGKO and littermate controls. In standard condition, pioglitazone and rosiglitazone do not affect myocardial metabolism while, fenofibrate treatment significantly increased CD36 and CPT1MIIA gene expression. In both CM-PGKO and control mice submitted to HFD, six weeks of treatment with rosiglitazone, fenofibrate and pioglitazone lowered myocardial lipid accumulation shifting myocardial substrate utilization towards greater contribution of glucose. In conclusion, at baseline, PPARγ does not play a crucial role in regulating cardiac metabolism in mice, probably due to its low myocardial expression. PPARs agonists, indirectly protect myocardium from lipotoxic damage likely reducing fatty acids delivery to the heart through the actions on adipose tissue. Nevertheless a direct non-PPARγ mediated mechanism of PPARγ agonist could not be ruled out.

Involvement of the ubiquitin-proteasome system in the formation of experimental postsurgical peritoneal adhesions.

We investigated the Ubiquitin-Proteasome System (UPS), major nonlysosomal intracellular protein degradation system, in the genesis of experimental postsurgical peritoneal adhesions. We assayed the levels of UPS within the adhered tissue along with the development of peritoneal adhesions and used the specific UPS inhibitor bortezomib in order to assess the effect of the UPS blockade on the peritoneal adhesions. We found a number of severe postsurgical peritoneal adhesions at day 5 after surgery increasing until day 10. In the adhered tissue an increased values of ubiquitin and the 20S proteasome subunit, NFkB, IL-6, TNF-α and decreased values of IkB-beta were found. In contrast, bortezomib-treated rats showed a decreased number of peritoneal adhesions, decreased values of ubiquitin and the 20S proteasome, NFkB, IL-6, TNF-α, and increased levels of IkB-beta in the adhered peritoneal tissue. The UPS system, therefore, is primarily involved in the formation of post-surgical peritoneal adhesions in rats.

Intraperitoneal oxygen/ozone treatment decreases the formation of experimental postsurgical peritoneal adhesions and the levels/activity of the local ubiquitin-proteasome system.

We have investigated whether an oxygen/ozone (95%O2/5%O3) mixture would have potential against the formation of experimental postsurgical peritoneal adhesions. In two groups of rats, one control intraperitoneally injected with 3 mL/rat of O2 and one intraperitoneally injected with oxygen/ozone mixture (3 mL/rat equivalent to 300 µg/kg ozone), we induced a midline laparotomy and an enterotomy at the level of the ileum to encourage the formation of peritoneal adhesions. Samples were taken from the parietal peritoneal tissue to assess the formation of adhesions 0 and 10 days after the surgical procedure and to assess the levels of ubiquitin and 20S proteasome. We found decreased formation of postsurgical peritoneal adhesions after treatment of the rats with 300 µg/kg ozone associated with a decreased levels of ubiquitin and 20S proteasome subunit within the adhered tissue. Oxygen/ozone mixture is potentially useful for approaching the post-surgical peritoneal adhesions, and the UPS system is involved in this.

Synthesis and Antihypertensive Action of New Imidazo[1,2-a]pyridine Derivatives , non Peptidic Angiotensin II Receptor Antagonists.

The synthesis and antihypertensive activity of a group of imidazo[1,2-a]pyridine is described. New synthesized compound have been tested both in vivo and in vitro as antagonists on Angiotensin AT1 receptor, and compared to Losartan, used as reference drug. Binding assay an Angiotensin AT1 receptor were carried on as well. Compounds 6b and 6g showed a potent antihypertensive activity and an high affinity on AT1 receptor.

Oxygen/ozone protects the heart from acute myocardial infarction through local increase of eNOS activity and endothelial progenitor cells recruitment.

The purpose of this study is to investigate whether an oxygen/ozone (O(2)/O(3)) mixture protects the heart from acute myocardial infarction through local involvement of endothelial nitric oxide synthase (eNOS) and endothelial progenitor cells (EPCs). Male Sprague-Dawley rats were subject to 25-min occlusion and 2-h reperfusion of the left descending coronary artery. O(2)/O(3) mixture was insufflated i.p. 30 min prior to ischemia/reperfusion (I/R) procedure at doses of 100, 150, and 300 microg/kg. Myocardial infarct size (IS) measurement and myocardial immunohistochemistry for EPCs were done. For these latter cells, immunoreactivities for CD34, and CD117/c-kit were assessed within the infarcted tissue. Moreover, cardiac eNOS was monitored. I/R in rats treated with O(2) produced an IS as a percentage of the area at risk (IS/AR) equal to 51 +/- 5%. I/R in rats treated with the O(2)/O(3) mixture showed reduced IS (for example, IS/AR for 150 microg/kg O(2)/O(3) was 35 +/- 2.1%; P < 0.01 vs. O(2)). The O(2)/O(3) cardio-protection was paralleled by an increased number of immunopositive particles per area for CD34 and CD117/c-kit. The increase of these markers was associated with an increase of cardiac eNOS expression as assayed by immunohistochemistry. Interestingly, N5-(1-Iminoethyl)-L-ornithine dihydrochloride (L-NIO), a selective eNOS activity inhibitor (30 mg/kg s.c.), prior to O(2)/O(3) and I/R almost abolished the cardio-protection exerted by the O(2)/O(3) mixture. L-NIO also abolished the increase in immunostaining for CD-34 and CD117/c-kit as compared with the rats receiving O(2)/O(3) and I/R only. O(2)/O(3) mixture protects the heart from acute myocardial infarction through local increase of eNOS expression/activity and consequent EPCs recruitment.

The cardio-protective properties of Ncx-6550, a nitric oxide donating pravastatin, in the mouse.

OBJECTIVE: Determine the cardio-protective properties of a nitric oxide-releasing pravastatin (Ncx-6550), in comparison to pravastatin. METHODS: A mouse model of myocardial infarct was used assessing tissue damage both at 2 and 24 hour post-reperfusion, administering compounds both prophylactically and therapeutically. RESULTS: Ncx-6550 induced a significant dose-dependent (2.24-22.4 micromol/kg i.p.) cardioprotection in the two hour reperfusion protocol. In vehicle-treated mice, infarct size (expressed as fraction of area at risk; IS/AR) was 41.2 +/- 1%, and it was reduced to 22.2 +/- 0.9% and 32.6 +/- 0.9% following 22.4 and 6.72 micromol/kg Ncx-6550 (p < 0.05). 22.4 micromol/kg Ncx-6550 also increased cardiac levels of the enzyme heme oxygenase-1. Treatment of mice with pravastatin induced significant reduction of myocardial injury only at 22.4 micromol/kg (IS/AR value: 33.7 +/- 0.9%). In a 24 hour reperfusion protocol, Ncx-6550 and pravastatin were tested only at 22.4 micromol/kg i.p. being given either one hour prior to ischemia (prophylactic protocol) or one hour into reperfusion (therapeutic protocol). With either treatment scheme, Ncx-6550 produced higher cardioprotection compared to pravastatin, as reflected also by a reduction in the incidence of lethality as well as in circulating troponin I and interleukin-1beta levels. CONCLUSIONS: These results indicate Ncx-6550 as a novel therapeutic agent with a potential for the treatment of myocardial infarct.

Antiarrhythmic effect of acute oxygen-ozone administration to rats.

The antiarrhythmic effects of 100; 150; and 300microg/kg i.p. oxygen/ozone mixture were tested on arrhythmias induced by i) ischemia; ii) ischemia/reperfusion; iii) aconitine (15microg/kg/i.v.); potassium chloride (1.5% i.v.) in rats. 25min of cardiac left descending coronary artery ischemia caused severe incidence of ventricular tachycardia, ventricular fibrillation and mortality. These were significantly reduced by pre-treatment of rats with oxygen/ozone mixture at doses of 150 and 300microg/kg. In separate experiments using a protocol of 5min ischemia followed by 8min reperfusion this caused arrhythmias starting within 6+/-1s. The incidence of ventricular tachycardia was 100%, while ventricular fibrillation occurred in 75% of the animals and lasted 85+/-14s. The mortality was 62.5%. These figures were significantly (P<0.01) reduced in animals treated with 150microg/kg oxygen/ozone and a substantial increase observed with 300microg/kg, whilst not affected by the lower dose of 100microg/kg. 150 and 300microg/kg oxygen/ozone prolonged the onset time for the appearance of arrhythmias induced by aconitine (300microg/kg oxygen/ozone, approximately 81% longer). Oxygen/ozone also reduced the ventricular tachycardia duration, ventricular fibrillation incidence, arrhythmia score, and increased the rat's survival rate. As for example, this latter was increased from 25% (aconitine) to 50% (aconitine+oxygen/ozone 150microg/kg). 100microg/kg oxygen/ozone was without effect. None of the oxygen/ozone doses affected the arrhythmias caused by potassium chloride 1.5% i.v. All the oxygen/ozone antiarrhythmic effects were similar to those observed with lidocaine (1.5mg/kg i.v.). In conclusion, oxygen/ozone has antiarrhythmic effects against arrhythmias caused by aconitine, myocardial ischemia and ischemia/reperfusion.

Long-term inhibition of dipeptidyl peptidase-4 in Alzheimer's prone mice.

We tested here the impact of a long-term inhibition of dipeptidyl peptidase-4 (DPP-4) with sitagliptin on the deposition of amyloid-beta within the brain and deficits in memory-related behavioral paradigms in a model of Alzheimer's disease (AD): double transgenic mice B6*Cg-Tg(APPswe,PSEN1dE9)85Dbo/J. Mice began to receive sitagliptin at 7 months of age. Three different dose of sitagliptin (5, 10 and 20 mg/kg), were administered daily for 12 weeks by gastric gavage. The treatments counteracted: (i) the memory impairment in the contextual fear conditioning test; (ii) increased the brain levels of GLP-1; (iii) produced significant reductions of nitrosative stress and inflammation hallmarks within the brain, as well as (iv) a significant diminution in the ultimate number and total area of betaAPP and Abeta deposits. All these effects much more evident for the dose of 20 mg/kg sitagliptin. The long-term inhibition of the endogenous DPP-4 enzymes with sitagliptin can significantly delay some forms of AD pathology, including amyloid deposition, when administered early in the disease course of a transgenic mouse model of AD.

Myocardial lipid accumulation in patients with pressure-overloaded heart and metabolic syndrome.

We evaluated the role of sterol-regulatory element binding protein (SREBP)-1c/peroxisome proliferator activated receptor-gamma (PPARgamma) pathway on heart lipotoxicity in patients with metabolic syndrome (MS) and aortic stenosis (AS). Echocardiographic parameters of heart function and structural alterations of LV specimens were studied in patients with (n = 56) and without (n = 61) MS undergoing aortic valve replacement. Tissues were stained with hematoxylin-eosin (H and E) and oil red O for evidence of intramyocyte lipid accumulation. The specimens were also analyzed with PCR, Western blot, and immunohistochemical analysis for SREBP-1c and PPARgamma. Ejection fraction (EF) was lower in MS compared with patients without MS (P < 0.001); no difference was found in aortic orifice surface among the groups. H and E and oil red O staining of specimens from MS patients revealed several myocytes with intracellular accumulation of lipid, whereas these alterations were not detected in biopsies from patients without MS. Patients without MS have low levels and weak immunostaining of SREBP-1c and PPARgamma in heart specimens. In contrast, strong immunostaining and higher levels of SREBP-1c and PPARgamma were seen in biopsies from the MS patients. Moreover, we evidenced a significative correlation between both SREBP-1c and PPARgamma and EF and intramyocyte lipid accumulation (P < 0.001). SREBP-1c may contribute to heart dysfunction by promoting lipid accumulation within myocytes in MS patients with AS; SREBP-1c may do it by increasing the levels of PPARgamma protein.

Tight glycemic control reduces heart inflammation and remodeling during acute myocardial infarction in hyperglycemic patients.

OBJECTIVES: We analyzed the molecular mechanisms evoked by tight glycemic control during post-infarction remodeling in human hearts. BACKGROUND: The molecular mechanisms by which tight glycemic control improves heart remodeling during acute myocardial infarction (AMI) are still largely unknown. METHODS: Eighty-eight patients with first AMI undergoing coronary bypass surgery were studied: 38 normoglycemic patients served as the control group; hyperglycemic patients (glucose >or=140 mg/dl) were randomized to intensive glycemic control (IGC) (n = 25; glucose 80 to 140 mg/dl) or conventional glycemic control (CGC) (n = 25; glucose 180 to 200 mg/dl) for almost 3 days before surgery, with insulin infusion followed by subcutaneous insulin treatment. Echocardiographic parameters were investigated at admission and after treatment period. During surgery, oxidative stress (nitrotyrosine, superoxide anion [O(2)(-)] production, inducible nitric oxide synthase [iNOS]), inflammation (nuclear factor kappa B [NFkappaB], tumor necrosis factor [TNF]-alpha, and apoptosis (caspase-3) were analyzed in biopsy specimens taken from the peri-infarcted area. RESULTS: Compared with normoglycemic patients, hyperglycemic patients had higher myocardial performance index (MPI) (p < 0.05), reduced ejection fraction (p < 0.05), more nitrotyrosine, iNOS, and O(2)(-) production, more macrophages, T-lymphocytes, and HLA-DR (Dako, Milan, Italy) cells, and more NFkappaB-activity, TNF-alpha, and caspase-3 levels (p < 0.01) in peri-infarcted specimens. After the treatment period, plasma glucose reduction was greater in the IGC than in the CGC group (p < 0.001). Compared with IGC patients, CGC patients had higher MPI (p < 0.02), had lower ejection fraction (p < 0.05), and had more markers of oxidative stress, more inflammation and apoptosis (p < 0.01) in peri-infarcted specimens. CONCLUSIONS: Tight glycemic control, by reducing oxidative stress and inflammation, might reduce apoptosis in peri-infarcted areas and remodeling in AMI patients.

The ubiquitin-proteasome system contributes to the inflammatory injury in ischemic diabetic myocardium: the role of glycemic control.

BACKGROUND: Because the ubiquitin-proteasome pathway (UPS) is required for activation of nuclear factor kappa beta (NFkB), a transcription factor that regulates inflammatory genes, we evaluated the UPS activity, NFkB activation, and tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, in ischemic specimens of diabetic myocardium and relate them to the glycemic control (HbA(1c)), oxidative stress (nitrotyrosine, a modified amino acid produced by reactive O(2)), and cardiac outcome (echocardiographic parameters). Moreover, the role of UPS, NFkB, and TNF-alpha in the cardiac tissue injury of acute ischemia/reperfusion (I/R) was evaluated in streptozotocin (STZ)-hyperglycemic rats. Finally, this study aimed to elucidate whether an intervention on UPS with bortezomib, an inhibitor of UPS, may counteract the extensive myocardial infarction and increased inflammatory reaction into the hyperglycemic myocardium. METHODS: Ventricular biopsy specimens from 16 nondiabetic and 18 type 2 diabetic patients presenting with unstable angina who underwent coronary artery bypass were collected during coronary bypass surgery. Ejection fraction (EF); myocardial performance index (MPI), which measures both systolic and diastolic function, immunostaining, and cardiac levels of nitrotyrosine; UPS activity; NFkB; and TNF-alpha were investigated in both ischemic human myocardium and heart tissue from STZ-hyperglycemic rats subject to a myocardial ischemia/reperfusion procedure. RESULTS: We found that diabetic patients had higher MPI (P<.041) and reduced EF (P<.008) compared with nondiabetic patients. Diabetic specimens had higher nitrotyrosine, UPS activity, NFkB, and TNF-alpha levels compared with nondiabetic patients (P<.001). This was mirrored by consistently high levels of UPS and inflammatory markers in STZ-infarcted hearts, associated with high myocardial damage. In contrast, lesions from normoglycemic animals as well as from hyperglycemic rats treated with bortezomib showed low levels of ubiquitin-proteasome activity, inflammation, and myocardial damage (P<.01). CONCLUSIONS: By contributing to the increased inflammation, the UPS overactivity may enhance the risk of complication during myocardial ischemia in diabetic patients.