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Introduction:The purine analog 6-thioguanine (6TG), an old drug approved in the 60s to treat acute myeloid leukemia (AML), was tested in the diabetic retinopathy (DR) experimental in vivo setting along with a molecular modeling approach.Methods:A computational analysis was performed to investigate the interaction of 6TG with MC1R and MC5R. This was confirmed in human umbilical vein endothelial cells (HUVECs) exposed to high glucose (25 mM) for 24 h. Cell viability in HUVECs exposed to high glucose and treated with 6TG (0.05–0.5–5 µM) was performed. To assess tube formation, HUVECs were treated for 24 h with 6TG 5 µM and AGRP (0.5–1–5 µM) or PG20N (0.5–1–5–10 µM), which are MC1R and MC5R antagonists, respectively. For the in vivo DR setting, diabetes was induced in C57BL/6J mice through a single streptozotocin (STZ) injection. After 2, 6, and 10 weeks, diabetic and control mice received 6TG intravitreally (0.5–1–2.5 mg/kg) alone or in combination with AGRP or PG20N. Fluorescein angiography (FA) was performed after 4 and 14 weeks after the onset of diabetes. After 14 weeks, mice were euthanized, and immunohistochemical analysis was performed to assess retinal levels of CD34, a marker of endothelial progenitor cell formation during neo-angiogenesis.Results:The computational analysis evidenced a more stable binding of 6TG binding at MC5R than MC1R. This was confirmed by the tube formation assay in HUVECs exposed to high glucose. Indeed, the anti-angiogenic activity of 6TG was eradicated by a higher dose of the MC5R antagonist PG20N (10 µM) compared to the MC1R antagonist AGRP (5 µM). The retinal anti-angiogenic effect of 6TG was evident also in diabetic mice, showing a reduction in retinal vascular alterations by FA analysis. This effect was not observed in diabetic mice receiving 6TG in combination with AGRP or PG20N. Accordingly, retinal CD34 staining was reduced in diabetic mice treated with 6TG. Conversely, it was not decreased in diabetic mice receiving 6TG combined with AGRP or PG20N.Conclusion:6TG evidenced a marked anti-angiogenic activity in HUVECs exposed to high glucose and in mice with DR. This seems to be mediated by MC1R and MC5R retinal receptors.

Objective: We evaluated sodium-glucose co-transporter2 (SGLT2) expression and the effect of SGLT2 inhibitor (SGLT2i) therapies on carotid plaques of asymptomatic diabetic and non-diabetic patients. Methods: Plaques were obtained from 296 non-diabetic patients and 227 patients with type 2 diabetes undergoing carotid endarterectomy. 97 patients with type 2 diabetes were treated with SGLT2 inhibitors for 16 ± 4 months before endarterectomy. After propensity score matching analysis, patients with type 2 diabetes were categorized without (n = 87) and with SGLT2i therapy (n = 87). To investigate SGLT2 expression levels' effects on major adverse endpoints (MACE = stroke, transient ischemic attack, myocardial infarction, and death), we evaluated MACE outcomes at a 2-year follow-up. Results: Compared to plaques from patients without diabetes, plaques from patients with diabetes had higher SGLT2 expression, inflammation, and oxidative stress, along with lower SIRT6 expression and collagen content. Compared with plaques from patients with diabetes, SGLT2i-treated patients with type 2 diabetes presented increased SIRT6 expression and collagen content and lowered inflammation and ion and oxidative stress, thus indicating a more stable plaque phenotype. These results supported in vitro observations on human aorta endothelial cells (EC) (TeloHAEC-cells). Indeed, EC treated with high glucose (25 mM) in the presence of SGLT2i (100 nM canagliflozin) presented higher SIRT6 expression and decreased mRNA and protein SGLT2 levels, nuclear factor-kappa B (NF-B(NF-κB), and matrix metallopeptidase 9 (MMP-9) expression compared to cells treated only with high glucose. After two years following endarterectomy, a multivariable Cox regression analysis showed significantly higher 2-year overall survival from MACE in patients without diabetes (P

Moderate exercise training may not be sufficient to exert beneficial effects on the cardiovascular system because of the long-term multifactorial etiology of diabetic complications. The addition of a proper pharmacological tool to the physical exercise should improve the outcomes of the diabetic damage. Here it is shown that 8 weeks exercise training of type 1 diabetic Sprague-Dawley (SD) rats resulted in a significantly increased heart rate, a 14% increase in the left ventricular ejection fraction (LVEF) increased plasma insulin levels and a 13% decrease in plasma glucose with respect to sedentary animals. The training also resulted in a 22% reduction in cardiac QT interval from a diabetic sedentary value of 185 ± 19 ms. Treatment of trained rats with the new antioxidant and NO-releasing aldose reductase 2 inhibitor 5(6)-(benzo[d]thiazol-2-ylmethoxy) benzofuroxane BF-5m, 20 mg/kg/day, added a further and significant (P < 0.01 vs. sedentary) increase of the LVEF up to 38% at 8 week time point. The long QT interval recorded in trained rats was reduced to further 12% by addition to the training of pharmacological treatment with 20 mg/kg/day BF-5m. At this time, the association of the two treatments improved the expression into the cardiac tissue of sarcoplasmic reticulum Ca2+ ATPase 2 (SERCA2) and manganese superoxide dismutase (MnSOD), and reduced the fibrosis.

Background and purpose: pericoronary fat over-inflammation might lead to the development and destabilization of coronary plaque in patients with pre-diabetes (PDM). Notably, pericoronary fat could over-express the sodium-glucose cotransporter 2 (SGLT2) and leptin, along with decreased sirtuin 6 (SIRT6) expression in PDM vs. normoglycemic (NG) patients undergoing coronary artery bypass grafting (CABG) for acute myocardial infarction (AMI). However, in the current study, we evaluated inflammatory markers, SGLT2, SIRT6, and leptin levels in pericoronary fat and, subsequently, 12-month prognosis comparing PDM to NG subjected to CABG for AMI. In addition, we evaluated in PDM patients the effects of metformin therapy on SIRT6 expression, leptin, and SGLT2 levels, and assessed its beneficial effect on nitrotyrosine and inflammatory cytokine levels. Methods: we studied AMI patients referred for CABG, divided into PDM and NG-patients. PDM patients were divided into never-metformin users and metformin users. Finally, we evaluated major adverse cardiac events (MACE) at a 12-month follow-up. Results: the MACE was 9.1% in all PDM and 3% in NG patients (p < 0.05). Metformin users presented a significantly lower MACE rate in PDM than never-metformin users (p < 0.05). PDM showed higher inflammatory cytokines, 3-nitrotyrosine levels, SGLT2, and leptin content, and decreased SIRT6 protein levels in pericoronary fat compared to NG-patients (p < 0.05). PDM never-metformin-users showed higher SGLT2 and leptin levels in pericoronary fat than current-metformin-users (p < 0.05). Conclusions: metformin therapy might ameliorate cardiovascular outcomes by reducing inflammatory parameters, SGLT2, and leptin levels, and finally improving SIRT6 levels in AMI-PDM patients treated with CABG.

Objectives: In obese patients the superficial adipose tissue expresses cytokines, and sirtuins, that may affect myocardial function. In this study, we investigated the effect of metformin therapy added to a hypocaloric diet on the inflammatory pattern and cardiac performance (MPI) in obese patients with pre-diabetic condition.Materials and Methods: Fifty-eight obese patients that were enrolled for abdominoplastic surgery were divided into patients with pre-diabetic condition (n 40) and normo-glycemic patients (n18). Patients with pre-diabetic condition were randomly assigned to metformin therapy added to a hypocaloric diet (group 1, n 20) or to a hypocaloric diet therapy alone (group 2, n20). Patients with normo-glycemic condition were assigned to a hypocaloric diet therapy.Results: During enrollment, obese patients with a pre-diabetic condition (group 1 and 2) presented higher glucose values, lower values of insulin, and higher values of the homeostasis model for the assessment of insulin resistance (HOMA-IR) than obese patients with normo-glycemic condition(group 3). In addition, they had higher values of C Reactive protein (CRP), interleukin 6 (IL6), and lower values of sirtuin 1(SIRT1). In the 12th month of the follow-up, metformin therapy induced in patients with pre-diabetic condition (group 1) a significant reduction of glucose values, HOMA-IR, and inflammatory markers such as CRP (1.04 ± 0.48 vs. 0.49 ± 0.02 mmol/L, p < 0.05), IL6 (4.22 ± 0.45 vs. 3.33 ± 0.34 pg/ml, p < 0.05), TNFα (6.95 ± 0.59 vs. 5.15 ± 0.44 pg/ml, p < 0.05), and Nitrotyrosine (5,214 ± 0,702 vs. 2,151 ± 0,351 nmol/l, p < 0.05). This was associated with a significant reduction of Intima-media thickness (1.01 ± 0.15 vs. 0.86 ± 0.15 mm, p < 0.05), Septum (14 ± 2.5 vs. 10.5 ± 2 mm, p < 0.05), Posterior wall (11 ± 1.5 vs. 8 ± 1 mm, p < 0.05), LV mass (192.5 ± 49.5 vs. 133.2 ± 37.6 g, p < 0.05) and of MPI (0.58 ± 0.03 vs. 0.38 ± 0.02, p < 0.05). At 12 months of follow-up, group 2 experienced only a reduction of cholesterol (4.15 ± 0.94 vs. 4.51 ± 0.88 mmol/L, p < 0.05) and triglycerides (1.71 ± 1.18 vs. 1.83 ± 0.54 mmol/L, p < 0.05). At 12 months of follow-up, group 3 experienced a significant reduction of inflammatory markers, and also of echographic parameters, associated with amelioration of myocardial performance. To date, IL6 expression was related to higher values of left ventricle mass (R-value 0.272, p-value 0.039), and to higher IMT (R-value 0.272, p-value 0.039), such as those observed for CRP (R-value 0.308, p-value 0.021), for glucose blood values (R-value 0.449, p-value 0.001), and for HOMA-IR (R-value 0.366, p-value 0.005). An inverse correlation was found between subcutaneous fat expression of SIRT1 and myocardial performance index (R-value−0.236, p-value 0.002).Conclusion: In obese patients with pre-diabetic condition a metformin therapy may reduce inflammation and oxidative stress, and this may be associated with the amelioration of the cardiac performance.Clinical research trial number: NCT03439592.

We evaluated the role of sterol-regulatory element binding protein (SREBP)-1c/peroxisome proliferator activated receptor-γ (PPARγ) 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 PPARγ. 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 PPARγ in heart specimens. In contrast, strong immunostaining and higher levels of SREBP-1c and PPARγ were seen in biopsies from the MS patients. Moreover, we evidenced a significative correlation between both SREBP-1c and PPARγ 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 PPARγ protein.

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.

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.

This study investigated whether the administration of resolvin D1 to rats with endotoxininduced uveitis (EIU) ameliorates the immuno-inflammatory profile of the eye. 24 h after the administration of 200 μg LPS into the footpad of Sprague-Dawley rats, severe changes of the structure of the eye occurred concomitantly with a severe inflammatory and immune response. These latter included strong infiltration of PMN leukocytes CD11b+ T-lymphocytes CD4+ and CD8+ within the eye and a significant release of the cytokines/chemokines TNF-alpha, CXCL8, and RANTES too. Bolus of resolvin D1 (RvD1; 10-100-1000 ng/kg in 200 μL of sterile saline via the tail vein) significantly and dose-dependently (i) reduced the development of the ocular derangement caused by LPS; (ii) reduced the clinical score attributed to EIU; (iii) reduced the protein concentration and myeloperoxidase activity (MPO) in aqueous humor (AqH); and (iv) reduced neutrophils, T-lymphocytes, and cytokines within the eye. [ABSTRACT FROM AUTHOR]