The prevention of diabetic cardiomyopathy by non-mitogenic acidic fibroblast growth factor is probably mediated by the suppression of oxidative stress and damage

Anti-inflammatory, Antioxidant, and Wound-Healing Effects of Photobiomodulation on Type-2 Diabetic Rats

Introduction: In the current study, the effects of photobiomodulation (PBM) treatments were examined based on biomechanical and histological criteria and mRNA levels of catalase (CAT), superoxide dismutase (SOD), and NADPH oxidase (NOX) 1 and 4 in a postponed, ischemic, and infected wound repair model (DIIWHM) in rats with type 2 diabetes (DM2) during the inflammation (day 4) and proliferation (day 8) stages. Methods: To study ischemic wound repair in a diabetic rat model (DIIWHM), 24 rats with type-2 diabetes were randomly divided into four groups and infected with methicillin-resistant Staphylococcus aureus (MRSA). The control groups consisted of CG4 (control group on day 4) and CG8 (control group on day 8), while the PBM groups comprised PBM4 (PBM treatment group on day 4) and PBM8 (PBM treatment group on day 8). These group assignments allowed for comparisons between the control groups and the PBM-treated groups at their respective time points during the study. Results: On days 4 and 8 of wound restoration, the PBM4 and PBM8 groups showed substantially modulated inflammatory responses and improved formation of fibroblast tissue compared with the CG groups (P<0.05). Concurrently, the effects of PBM8 were significantly superior to those of PBM4 (P<0.05). The antioxidant results on days 4 and 8 revealed substantial increases in CAT and SOD in the PBM groups compared with the CGs (P<0.05). Substantial decreases were observed in the antioxidant agents NOX1 and NOX4 of the PBM4 and PBM8 groups compared with both CGgroups (P<0.05). Conclusion: PBM treatments significantly sped up the inflammatory and proliferating processes in a DHIIWM in DM2 animals by modifying the inflammatory reaction and boosting fibroblast proliferation. Overall, the current findings indicated substantially better results in the PBM groups than in the CG groups.

Bibliometric analysis of the inflammation in diabetic cardiomyopathy

Background

Maladaptive inflammation is implicated in the development of diabetic cardiomyopathy (DCM). This study aimed to visually analyze the global scientific output over the past two decades regarding research on inflammation associated with DCM.

Methods

All relevant articles and reviews were retrieved in the Web of Science (WOS) Core Collection (limited to SCIE) using "inflammation" and "diabetic cardiomyopathy" as search terms. Articles and reviews published from 1 January 2001 to 28 February 2021 were collected. Visualization analysis and statistical analysis were conducted by Microsoft 365 Excel and VOSviewer 1.6.18.

Results

A total of 578 documents were finally selected for further analysis. The publications regarding inflammation and DCM increased gradually over approximately 20 years. The most prolific country was China, with 296 documents and the most citations (9,366). The most influential author groups were Lu Cai and Yihui Tan who were from the United States. The bibliometric analysis of co-occurrence keywords showed that inflammation in DCM is composed of numerous molecules (NF-κB, NLRP3 inflammasome, Nrf-2, TNF-α, protein kinase C, PPARα, TLR4, p38 mitogen-activated protein kinase, TGF-β, Sirt1, and AKT), a variety of cardiac cell types (stem cell, fibroblast, and cardiomyocyte), physiological processes (apoptosis, oxidative stress, autophagy, endoplasmic reticulum stress, hypertrophy, mitochondrion dysfunction, and proliferation), and drugs (sulforaphane, metformin, empagliflozin, and rosuvastatin).

Conclusion

Our bibliometric analysis presents the characteristics and trends of inflammation in DCM and shows that research on inflammation in DCM will continue to be a hotspot.

Nanoparticles application as a therapeutic strategy for diabetes mellitus management

The prevalence of diabetes, as reported by the World Health Organization and the International Diabetes Federation, has raised many eyebrows about the dangers of diabetes mellitus to society, leading to the development of various therapeutic techniques, including nanotechnological, in the management of this disease. This review discusses silver, gold, ceramic, alloy, magnetic, silica, polymeric nanoparticles and their various applications in diabetes management which may help to reduce the incidence of diabetes and its complication.

Emerging Theranostic Nanomaterials in Diabetes and Its Complications

Diabetes mellitus (DM) refers to a group of metabolic disorders that are characterized by hyperglycemia. Oral subcutaneously administered antidiabetic drugs such as insulin, glipalamide, and metformin can temporarily balance blood sugar levels, however, long-term administration of these therapies is associated with undesirable side effects on the kidney and liver. In addition, due to overproduction of reactive oxygen species and hyperglycemia-induced macrovascular system damage, diabetics have an increased risk of complications. Fortunately, recent advances in nanomaterials have provided new opportunities for diabetes therapy and diagnosis. This review provides a panoramic overview of the current nanomaterials for the detection of diabetic biomarkers and diabetes treatment. Apart from diabetic sensing mechanisms and antidiabetic activities, the applications of these bioengineered nanoparticles for preventing several diabetic complications are elucidated. This review provides an overall perspective in this field, including current challenges and future trends, which may be helpful in informing the development of novel nanomaterials with new functions and properties for diabetes diagnosis and therapy.

Establishing F1A-CreERT2 Mice to Trace Fgf1 Expression in Adult Mouse Cardiomyocytes

Fibroblast growth factor 1 (FGF1) regulates many biological and physiological processes. In mice, Fgf1 gene contains at least three upstream promoters and are alternatively spliced to the first protein coding exon, giving rise to different Fgf1 mRNA variants (1A, 1B and 1G). Among them, the Fgf1A transcript is predominantly expressed in the heart. FGF1 can induce cardiomyocyte regeneration and cardiogenesis in vitro and in vivo. Here, we generated a novel mouse line using the Fgf1A promoter (F1A) driving the expression of the inducible Cre recombinase (CreER^T2). We firstly demonstrated that the highest mRNA expression of CreER^T2 were detected in the heart specifically of F1A-CreER^T2 mice, similar to that of Fgf1A mRNA. The F1A-CreER^T2 mice were crossed with ROSA26 mice, and the F1 mice were analyzed. The LacZ-positive signals were detected exclusively in the heart after tamoxifen administration. The CreER^T2-mediated recombination in the tissues is monitored through LacZ-positive signals, indicating the in situ localization of F1A-positive cells. Consistently, these F1A-positive cells with RFP-positive signals or LacZ-positive blue signals were co-localized with cardiomyocytes expressing cardiac troponin T, suggesting cardiomyocyte-specific activation of Fgf1A promoter. Our data suggested that the F1A-CreER^T2 mouse line could be used for time-dependent and lineage tracing of Fgf1A-expressing cells in vivo.

Fibroblast Growth Factor Type 1 Ameliorates High-Glucose-Induced Oxidative Stress and Neuroinflammation in Retinal Pigment Epithelial Cells and a Streptozotocin-Induced Diabetic Rat Model

Diabetic retinopathy (DR) is a common complication of diabetes that causes severe visual impairment globally. The pathogenesis of DR is related to oxidative stress and chronic inflammation. The fibroblast growth factor type 1 (FGF-1) mitogen plays crucial roles in cell function, development, and metabolism. FGF-1 is involved in blood sugar regulation and exerts beneficial antioxidative and anti-inflammatory effects on various organ systems. This study investigated the antioxidative and anti-inflammatory neuroprotective effects of FGF-1 on high-glucose-induced retinal damage. The results revealed that FGF-1 treatment significantly reversed the harmful effects of oxidative stress and inflammatory mediators in retinal tissue in a streptozotocin-induced diabetic rat model. These protective effects were also observed in the in vitro model of retinal ARPE-19 cells exposed to a high-glucose condition. We demonstrated that FGF-1 attenuated p38 mitogen-activated protein kinase and nuclear factor-κB pathway activation under the high-glucose condition. Our results indicated that FGF-1 could effectively prevent retinal injury in diabetes. The findings of this study could be used to develop novel treatments for DR that aim to reduce the cascade of oxidative stress and inflammatory signals in neuroretinal tissue.

aFGF Targeted Mediated by Novel Nanoparticles-Microbubble Complex Combined With Ultrasound-Targeted Microbubble Destruction attenuates Doxorubicin-Induced Heart Failure via Anti-Apoptosis and Promoting Cardiac Angiogenesis

The purpose of this study was to evaluate the protective effect of acidic fibroblast growth factor targeted mediated by novel nanoparticles–cationic lipid microbubbles complex (aFGF–NP + CPMBs) combined with ultrasound targeted microbubble destruction (UTMD)on doxorubicin–induced heart failure (HF)and its mechanism. Heart failure rats induced by intraperitoneal injection with doxorubicin (DOX) to achieve cummulative dose of 15mg/kg for continuous 6 weeks showed left ventricular dysfunction, seriously oxidative stress, cardiomyocyte apoptosis, and decrease of myocardial vascular density. In contrast, aFGF–NP + CPMBs combined with UTMD therapy (3ug/kg, caudal vein injection, twice a week, 6weeks)prominently ameliorated left ventricular dysfunction by increased ejection fraction (EF) and fractional shortening (FS), decreased brain natriuretic peptide (BNP); strengthened the ability of antioxidant stress confirmed by increasing the activity of SOD and reducing the production of MDA; exerted the effect of anti–cardiomyocyte apoptosis and promotion angiogenesis by inhibited Bax expression and increased Bcl–2 expression and platelet endothelial cell adhesion molecule (CD31) expression. Taken together, the research suggested that aFGF targeted mediated by novel nanoparticles–cationic lipid microbubbles complex combined with UTMD should be a promising targeted treatment for heart failure.

Acidic fibroblast growth factor attenuates type 2 diabetes-induced demyelination via suppressing oxidative stress damage

Prolonged type 2 diabetes mellitus (T2DM) produces a common complication, peripheral neuropathy, which is accompanied by nerve fiber disorder, axon atrophy, and demyelination. Growing evidence has characterized the beneficial effects of acidic fibroblast growth factor (aFGF) and shown that it relieves hyperglycemia, increases insulin sensitivity, and ameliorates neuropathic impairment. However, there is scarce evidence on the role of aFGF on remodeling of aberrant myelin under hyperglycemia condition. Presently, we observed that the expression of aFGF was rapidly decreased in a db/db T2DM mouse model. Administration of exogenous aFGF was sufficient to block acute demyelination and nerve fiber disorganization. Furthermore, this strong anti-demyelinating effect was most likely dominated by an aFGF-mediated increase of Schwann cell (SC) proliferation and migration as well as suppression of its apoptosis. Mechanistically, the beneficial biological effects of aFGF on SC behavior and abnormal myelin morphology were likely due to the inhibition of hyperglycemia-induced oxidative stress activation, which was most likely activated by kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid-derived-like 2 (Nrf2) signaling. Thus, this evidence indicates that aFGF is a promising protective agent for relieving myelin pathology through countering oxidative stress signaling cascades under diabetic conditions.

Nanotechnology in the Treatment of Diabetic Complications: A Comprehensive Narrative Review

In today's society, the prevention and treatment of diabetes mellitus and its subsequent complications have brought trouble to human beings. Complications caused by diabetes bring not only physical and mental pain to patients but also a heavy economic burden to families. And once diabetic complications occur, they are often irreversible and very difficult. At present, some studies suggest that nanotechnology can treat some diabetic complications. This paper reviews the application of nanotechnology in the repair of diabetic segmental bone injury, the healing of diabetic skin ulcers, the therapeutic effect, and improvement strategies and deficiencies of nanotechnology in diabetic complications.

Fibroblast Growth Factor 21 Attenuates Diabetes-Induced Renal Fibrosis by Negatively Regulating TGF-β-p53-Smad2/3-Mediated Epithelial-to-Mesenchymal Transition via Activation of AKT

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is required for renal fibrosis, which is a characteristic of diabetic nephropathy (DN). Our previous study demonstrated that fibroblast growth factor 21 (FGF21) prevented DN associated with the suppressing renal connective tissue growth factor expression, a key marker of renal fibrosis. Therefore, the effects of FGF21 on renal fibrosis in a DN mouse model and the underlying mechanisms were investigated in this study.

METHODS

Type 1 diabetes mellitus was induced in C57BL/6J mice by intraperitoneal injections of multiple low doses of streptozotocin. Then, diabetic and non-diabetic mice were treated with or without FGF21 in the presence of pifithrin-α (p53 inhibitor) or 10-[4'-(N,N-Diethylamino)butyl]-2-chlorophenoxazine hydrochloride (10-DEBC) hydrochloride (Akt inhibitor) for 4 months.

RESULTS

DN was diagnosed by renal dysfunction, hypertrophy, tubulointerstitial lesions, and glomerulosclerosis associated with severe fibrosis, all of which were prevented by FGF21. FGF21 also suppressed the diabetes-induced renal EMT in DN mice by negatively regulating transforming growth factor beta (TGF-β)-induced nuclear translocation of Smad2/3, which is required for the transcription of multiple fibrotic genes. The mechanistic studies showed that FGF21 attenuated nuclear translocation of Smad2/3 by inhibiting renal activity of its conjugated protein p53, which carries Smad2/3 into the nucleus. Moreover pifithrin-α inhibited the FGF21-induced preventive effects on the renal EMT and subsequent renal fibrosis in DN mice. In addition, 10-DEBC also blocked FGF21-induced inhibition of renal p53 activity by phosphorylation of mouse double minute-2 homolog (MDM2).

CONCLUSION

FGF21 prevents renal fibrosis via negative regulation of the TGF-β/Smad2/3-mediated EMT process by activation of the Akt/MDM2/p53 signaling pathway.

Assessment of the Preventive Effect Against Diabetic Cardiomyopathy of FGF1-Loaded Nanoliposomes Combined With Microbubble Cavitation by Ultrasound

Acidic fibroblast growth factor (FGF1) has great potential in preventing diabetic cardiomyopathy. This study aimed to evaluate the preventive effect of FGF1-loaded nanoliposomes (FGF1-nlip) combined with ultrasound-targeted microbubble destruction (UTMD) on diabetic cardiomyopathy (DCM) using ultrasound examination. Nanoliposomes encapsulating FGF1 were prepared by reverse phase evaporation. DM model rats were established by intraperitoneal injection of streptozotocin (STZ), and different forms of FGF1 (FGF1 solution, FGF1-nlip, and FGF1-nlip+UTMD) were used for a 12-week intervention. According to the transthoracic echocardiography and velocity vector imaging (VVI) indexes, the LVEF, LVFS, and VVI indexes (Vs, Sr, SRr) in the FGF1-nlip+UTMD group were significantly higher than those in the DM model group and other FGF1 intervention groups. From the real-time myocardial contrast echocardiography (RT-MCE) indexes, the FGF1-nlip+UTMD group A and A×β showed significant differences from the DM model group and other FGF1 intervention groups. Cardiac catheter hemodynamic testing, CD31 immunohistochemical staining, and electron microscopy also confirmed the same conclusion. These results confirmed that the abnormalities, including myocardial dysfunction and perfusion impairment, could be suppressed to different extents by the twice weekly FGF1 treatments for 12 consecutive weeks (free FGF1, FGF1-nlip, and FGF1-nlip+UTMD), with the strongest improvements observed in the FGF1-nlip+UTMD group. In conclusion, the VVI and RT-MCE techniques can detect left ventricular systolic function and perfusion changes in DM rats, providing a more effective experimental basis for the early detection and treatment evaluation of DCM, which is of great significance for the prevention of DCM.

Curcumin Analogs Reduce Stress and Inflammation Indices in Experimental Models of Diabetes

Chronic inflammation and oxidative stress lead to a multitude of adverse cellular responses in target organs of chronic diabetic complications. Curcumin, a highly investigated phytochemical, has been shown to exhibit both anti-inflammatory and antioxidant activities. However, the clinical application of curcumin has been greatly limited due to a poor pharmacokinetic profile. To overcome these limitations, we have generated analogs of curcumin to enhance bioavailability and offer a preferable pharmacokinetic profile. Here, we explored the effects of two mono-carbonyl curcumin analogs, L2H21 and L50H46, in alleviating indices of inflammation and oxidative stress in cell culture and mouse model of diabetic complications. Our results show that L2H21 and L50H46 normalize inflammatory mediators (IL-6 and TNF-α), extracellular matrix proteins (FN and COL4α1), vasoactive factors (VEGF and ET-1) and a key transcriptional coactivator (p300) in cultured human retinal microvascular endothelial cells (HRECs) and dermal-derived microvascular endothelial cells (HMVECs) challenged with high levels of glucose. These curcumin analogs also reduced glucose-induced oxidative DNA damage as evidenced by 8-OHdG labeling. We further show that treatment of streptozotocin-induced diabetic mice with curcumin analogs prevents cardiac and renal dysfunction. The preservation of target tissue function was associated with normalization of pro-inflammatory cytokines and matrix proteins. Collectively, our results show that L2H21 and L50H46 offer the anti-inflammatory and antioxidant activities as has been reported for curcumin, and may provide a clinically applicable therapeutic option for the treatment of diabetic complications.

Reduction of cellular stress is essential for Fibroblast growth factor 1 treatment for diabetic nephropathy

Diabetic nephropathy (DN) is one of general and common complication of diabetes, which severely affects the physical and mental health of diabetic patients. Fibroblast growth factor 1 (FGF1), an effective control agent of blood glucose, plays an effective treatment role on diabetes-induced renal injury. But the specific molecule mechanism underlying it is still unclear. Since induction of cellular stress is the main and common mechanism of diabetes-induced complication, we hypothesized that reduction of cellular stress is also the molecular mechanism of FGF1 treatment for DN. Here, we have further confirmed that FGF1 significantly ameliorated the diabetes-induced renal interstitial fibrosis and glomerular damage. The expression levels of collagen and α-smooth muscle actin (α-SMA) also dramatically induced in kidney from db/db mice, but these effects were blocked by FGF1 administration. Our mechanistic investigation had further revealed that diabetes significantly induced oxidative stress, nitrosative stress, and endoplasmic reticulum (ER) stress with upregulation of malondialdehyde (MDA), nitrotyrosine level, ER stress makers and downregulation of antioxidant capacity (AOC). FGF1 treatment significantly attenuated the effect of diabetes on cellular stress. We conclude that FGF1-associated glucose decreases and subsequent reduction of cellular stress is the another potential molecule mechanism underlying FGF1 treatment for DN.

Antiremodeling Effect of Xanthine Oxidase Inhibition in a Canine Model of Atrial Fibrillation

In a canine rapid atrial stimulation model of atrial fibrillation (AF), we have demonstrated an increased production of reactive oxygen species (ROS) along with electrical and structural remodeling. In the present study, we hypothesized that antioxidants can suppress atrial remodeling canines with AF. We therefore evaluated the effect of febuxostat, a xanthine oxidase (XO) inhibitor and a pure antioxidant, on atrial remodeling.AF was produced by performing a 3-week rapid atrial pacing (400 bpm) in 13 dogs divided into three groups: pacing + febuxostat group (n = 5; atrial pacing with 50 mg/day of febuxostat (administration); pacing control group (n = 5; atrial pacing without any drug administration); and non-pacing group (n = 3). Electrophysiological studies were conducted in the first 2 groups every week. Atrial tissue fibrosis was evaluated by Azan and immunofluorescent staining of fibronectin. Oxidative stress was evaluated by DHE and FCF-DA staining.Shortening of the refractory period and increase in AF inducibility appeared gradually in the pacing control group, but such changes were suppressed in the pacing + febuxostat group (P = 0.05). The pacing control group showed increase in fibrosis, which was suppressed in the febuxostat group. In DHE and DCF-DA staining, the pacing control group showed an increase in oxidative stress, which was suppressed in the pacing + febuxostat group. The pacing control group exhibited fibronectin expression, which was suppressed in the pacing + febuxostat group.The antioxidant effect of febuxostat may achieve an inhibition of new-onset AF in canines.

L-Carnitine: An Antioxidant Remedy for the Survival of Cardiomyocytes under Hyperglycemic Condition

BACKGROUND

Metabolic alterations as hyperglycemia and inflammation induce myocardial molecular events enhancing oxidative stress and mitochondrial dysfunction. Those alterations are responsible for a progressive loss of cardiomyocytes, cardiac stem cells, and consequent cardiovascular complications. Currently, there are no effective pharmacological measures to protect the heart from these metabolic modifications, and the development of new therapeutic approaches, focused on improvement of the oxidative stress condition, is pivotal. The protective effects of levocarnitine (LC) in patients with ischemic heart disease are related to the attenuation of oxidative stress, but LC mechanisms have yet to be fully understood.

OBJECTIVE

The aim of this work was to investigate LC's role in oxidative stress condition, on ROS production and mitochondrial detoxifying function in H9c2 rat cardiomyocytes during hyperglycemia.

METHODS

H9c2 cells in the hyperglycemic state (25 mmol/L glucose) were exposed to 0.5 or 5 mM LC for 48 and 72 h: LC effects on signaling pathways involved in oxidative stress condition were studied by Western blot and immunofluorescence analysis. To evaluate ROS production, H9c2 cells were exposed to H₂O₂ after LC pretreatment.

RESULTS

Our in vitro study indicates how LC supplementation might protect cardiomyocytes from oxidative stress-related damage, preventing ROS formation and activating antioxidant signaling pathways in hyperglycemic conditions. In particular, LC promotes STAT3 activation and significantly increases the expression of antioxidant protein SOD2. Hyperglycemic cardiac cells are characterized by impairment in mitochondrial dysfunction and the CaMKII signal: LC promotes CaMKII expression and activation and enhancement of AMPK protein synthesis. Our results suggest that LC might ameliorate metabolic aspects of hyperglycemic cardiac cells. Finally, LC doses herein used did not modify H9c2 growth rate and viability.

CONCLUSIONS

Our novel study demonstrates that LC improves the microenvironment damaged by oxidative stress (induced by hyperglycemia), thus proposing this nutraceutical compound as an adjuvant in diabetic cardiac regenerative medicine.

Resveratrol attenuates high glucose-induced cardiomyocytes injury via interfering ROS-MAPK-NF-κB signaling pathway

Cardiomyocyte inflammatory injury is likely required for cardiomyocytes death under hyperglycemia condition. Resveratrol (Res) is famous for its anti-inflammatory effect. However, there are few reports about the anti-inflammatory effect of Res induced by high glucose in cardiomyocytes. The aim of the present study is to investigate the inflammatory effect of high glucose and the anti-inflammatory effect of Res induced by high glucose in cardiomyocytes. Primary cardiomyocytes were isolated from new born SD rats and high glucose (30 mmol/L) was used as a stimulant for cell injury. Cell viability was assayed by CCK-8 method; protein expression was identified by Western blot or ELISA, respectively. The production of reactive oxygen species (ROS) was observed under a fluorescence microscope. The results indicated that High glucose (30 mmol/L) significantly decreased the cell viability of cardiomyocytes after co-cultivated for 12 h and had a time-dependent manner, and increased IL-1β, IL-6 and TNF-α secretion in cardiomyocytes. The injury effect of high glucose involved in ROS-MAPK-NF-κB signaling pathway. For the reason that antioxidant NAC, ERK1/2, p38 MAPK and NF-κB specific pathway inhibitors was able to abolish the secretion of this inflammatory factors; pretreatment with antioxidant NAC significantly decreased the level of phosphorylated ERK1/2, p38 MAPK and nuclear NF-κB; pretreatment of PD98059 and SB203580 can significantly decrease NF-κB level in nuclei. After treatment with Res 20 μmol/L for 12 h, IL-1β, IL-6 and TNF-α secretion were markedly decreased, and the phosphorylation of ERK1/2, p38 MAPK and NF-κB level were also decreased. All the results showed that Res attenuates high glucose-induced inflammatory injury through ROS-ERK1/2/p38-NF-κB signaling pathway in cardiomyocytes.

Prevention of doxorubicin-induced cardiomyopathy using targeted MaFGF mediated by nanoparticles combined with ultrasound-targeted MB destruction

The present study seeks to observe the preventive effects of doxorubicin-induced cardiomyopathy (DOX-CM) in rats using targeted non-mitogenic acidic fibroblast growth factor (MaFGF) mediated by nanoparticles (NP) combined with ultrasound-targeted MB destruction (UTMD). DOX-CM rats were induced by intraperitoneally injected doxorubicin. Six weeks after intervention, the indices from the transthoracic echocardiography and velocity vector imaging showed that the left ventricular function in the MaFGF-loaded NP (MaFGF-NP) + UTMD group was significantly improved compared with the DOX-CM group. The increased malondialdehyde and decreased superoxide dismutase were observed in the DOX-CM group, while a significant increase in superoxide dismutase and a decrease in malondialdehyde were detected in the groups treated with MaFGF-NP + UTMD. From the Masson staining, the MaFGF-NP + UTMD group showed a significant difference from the DOX-CM group. The cardiac collagen volume fraction and the ratio of the perivascular collagen area to the luminal area number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling positive cells in the MaFGF-NP + UTMD group decreased to 8.9%, 0.55-fold, compared with the DOX-CM group (26.5%, 1.7-fold). From terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling staining, the results showed the strongest inhibition of apoptosis progress in MaFGF-NP + UTMD group. The immunohistochemical staining of the TGF-β1 in MaFGF-NP + UTMD group reached 3.6%, which was much lower than that of the DOX-CM group (12.6%). These results confirmed that the abnormalities, including left ventricular dysfunction, myocardial fibrosis, cardiomyocytes apoptosis and oxidative stress, could be suppressed by twice weekly MaFGF treatments for 6 consecutive weeks (free MaFGF or MaFGF-NP+/UTMD), with the strongest improvements observed in the MaFGF-NP + UTMD group. Western blot analyses of the heart tissue further revealed the highest pAkt levels, highest anti-apoptosis protein (Bcl-2) levels and strongest reduction in proapoptosis protein (Bax) levels in the MaFGF-NP + UTMD group. This study confirmed the preventive effects of DOX-CM in the rats with MaFGF-NP and UTMD by retarding myocardial fibrosis, inhibiting oxidative stress, and decreasing cardiomyocyte apoptosis.

Azilsartan ameliorates diabetic cardiomyopathy in young db/db mice through the modulation of ACE-2/ANG 1-7/Mas receptor cascade

Hyperglycemia up-regulates intracellular angiotensin II (ANG-II) production in cardiac myocytes. This study investigated the hemodynamic and metabolic effects of azilsartan (AZL) treatment in a mouse model of diabetic cardiomyopathy and whether the cardioprotective effects of AZL are mediated by the angiotensin converting enzyme (ACE)-2/ANG 1-7/Mas receptor (R) cascade. Control db/+ and db/db mice (n=5 per group) were treated with vehicle or AZL (1 or 3mg/kg/d oral gavage) from the age of 8 to 16weeks. Echocardiography was then performed and myocardial protein levels of ACE-2, Mas R, AT₁R, AT₂R, osteopontin, connective tissue growth factor (CTGF), atrial natriuretic peptide (ANP) and nitrotyrosine were measured by Western blotting. Oxidative DNA damage and inflammatory markers were assessed by immunofluorescence of 8-hydroxy-2'-deoxyguanosine (8-OHdG), tumor necrosis factor (TNF)-α and interleukin 6 (IL-6). Compared with db/+ mice, the vehicle-treated db/db mice developed obesity, hyperglycemia, hyperinsulinemia and diastolic dysfunction along with cardiac hypertrophy and fibrosis. AZL treatment lowered blood pressure, fasting blood glucose and reduced peak plasma glucose during an oral glucose tolerance test. AZL-3 treatment resulted in a significant decrease in the expression of cytokines, oxidative DNA damage and cardiac dysfunction. Moreover, AZL-3 treatment significantly abrogated the downregulation of ACE-2 and Mas R protein levels in db/db mice. Furthermore, AZL treatment significantly reduced cardiac fibrosis, hypertrophy and their marker molecules (osteopontin, CTGF, TGF-β1 and ANP). Short-term treatment with AZL-3 reversed abnormal cardiac structural remodeling and partially improved glucose metabolism in db/db mice by modulating the ACE-2/ANG 1-7/Mas R pathway.

Oleanolic acid protects against diabetic cardiomyopathy via modulation of the nuclear factor erythroid 2 and insulin signaling pathways

Oleanolic acid (OL) is a pentacyclic triterpene compound used for the treatment of hepatitis, liver fibrosis and liver cirrhosis. In China, there is no published research on the effect or biological utilization of OL on liver diseases. The aim of the present study was to investigate the protective effects of OL against diabetic cardiomyopathy and its possible mechanism. A rat model of diabetes was established using streptozotocin and the effect of OL on diabetic cardiomyopathy (DCM) was evaluated. The results demonstrated that OL significantly reversed the DCM-induced changes to body weight, heart rate, echocardiography and hemodynamics, phosphorylated-glycogen synthase (GS) and glycogen phosphorylase (GP) activity in diabetic rats (all P<0.01). Treatment of diabetic rats with OL significantly inhibited oxidative stress and activated heme oxygenase (HO)-1/nuclear factor erythroid 2 (Nrf2) signaling in a rat model of diabetes (both P<0.01). The results of the present study indicate that OL protects against DCM through the HO-1/Nrf2 and insulin modulating GS/GP signaling pathways.

The Role of p38 MAPK in the Development of Diabetic Cardiomyopathy

Diabetic cardiomyopathy (DCM) is a major complication of diabetes that contributes to an increase in mortality. A number of mechanisms potentially explain the development of DCM including oxidative stress, inflammation and extracellular fibrosis. Mitogen-activated protein kinase (MAPK)-mediated signaling pathways are common among these pathogenic responses. Among the diverse array of kinases, extensive attention has been given to p38 MAPK due to its capacity for promoting or inhibiting the translation of target genes. Growing evidence has indicated that p38 MAPK is aberrantly expressed in the cardiovascular system, including the heart, under both experimental and clinical diabetic conditions and, furthermore, inhibition of p38 MAPK activation in transgenic animal model or with its pharmacologic inhibitor significantly prevents the development of DCM, implicating p38 MAPK as a novel diagnostic indicator and therapeutic target for DCM. This review summarizes our current knowledge base to provide an overview of the impact of p38 MAPK signaling in diabetes-induced cardiac remodeling and dysfunction.

Dynamic monitoring of oxidative DNA double-strand break and repair in cardiomyocytes

DNA double-strand breaks (DSBs) are most dangerous lesions. To determine whether oxidative stress can induce DSBs and how they are repaired in cardiomyocytes (CMs), cultured neonatal rat CMs were treated with different doses of H2O2 and followed for up to 72 h for monitoring the spatiotemporal dynamics of DNA repair protein assembly/disassembly at DSB foci. The protein levels and foci numbers of histone H2AX phosphorylated at serine 139 (γ-H2AX) increased proportionally to 50, 100, and 200 μmol/L H2O2 after 30 min treatment. When H2O2 was at or above 400 μmol/L, γ-H2AX became predominantly pannuclear. After 30 min, 200 μmol/L of H2O2 treatment, γ-H2AX levels were highest within the first hour and then gradually declined during the recovery and returned to basal levels at 48 h. Among DNA damage transducer kinases, ataxia telangiectasia mutated (ATM) was significantly activated by H2O2 in contrast to mild activation of ATR (ATM and Rad3-related). A DSB binding protein, p53 binding protein 1, formed distinct nuclear foci that colocalized with γ-H2AX foci and phosphorylated ATM. Our findings indicate that DSBs can be induced by H2O2 and ATM is the main kinase to mediate DSB repair in CMs. Therefore, monitoring DSB repair can assess oxidative injury and response in CMs.

miR-30c Mediates Upregulation of Cdc42 and Pak1 in Diabetic Cardiomyopathy

AIM

Cardiac hypertrophy and myocardial fibrosis significantly contribute to the pathogenesis of diabetic cardiomyopathy (DCM). Altered expression of several genes and their regulation by microRNAs has been reported in hypertrophied failing hearts. This study aims to examine the role of Cdc42, Pak1, and miR-30c in the pathogenesis of cardiac hypertrophy in DCM.

METHODS

DCM was induced in Wistar rats by low-dose streptozotocin-high-fat diet for 12 weeks. Cardiac expression of Cdc42, Pak1 and miR-30c, and hypertrophy markers (ANP and β-MHC) was studied in DCM vs control rats and in high-glucose (HG)-treated H9c2 cardiomyocytes.

RESULTS

Diabetic rats showed cardiomyocyte hypertrophy, increased heart-to-body weight ratio, and an increased expression of ANP and β-MHC. Cardiac expression of Cdc42 and Pak1 genes was increased in diabetic hearts and in HG-treated cardiomyocytes. miR-30c was identified to target Cdc42 and Pak1 genes, and cardiac miR-30c expression was found to be decreased in DCM rats, patients with DCM, and in HG-treated cardiomyocytes. miR-30c overexpression decreased Cdc42 and Pak1 genes and attenuated HG-induced cardiomyocyte hypertrophy, whereas miR-30c inhibition increased Cdc42 and Pak1 gene expression and myocyte hypertrophy in HG-treated cardiomyocytes.

CONCLUSION

Downregulation of miR-30c mediates prohypertrophic effects of hyperglycemia in DCM by upregulation of Cdc42 and Pak1 genes.

Erythropoietin and diabetes mellitus

Erythropoietin (EPO) is a 30.4 kDa growth factor and cytokine that governs cell proliferation, immune modulation, metabolic homeostasis, vascular function, and cytoprotection. EPO is under investigation for the treatment of variety of diseases, but appears especially suited for the treatment of disorders of metabolism that include diabetes mellitus (DM). DM and the complications of this disease impact a significant portion of the global population leading to disability and death with currently limited therapeutic options. In addition to its utility for the treatment of anemia, EPO can improve cardiac function, reduce fatigue, and improve cognition in patients with DM as well as regulate cellular energy metabolism, obesity, tissue repair and regeneration, apoptosis, and autophagy in experimental models of DM. Yet, EPO can have adverse effects that involve the vasculature system and unchecked cellular proliferation. Critical to the cytoprotective capacity and the potential for a positive clinical outcome with EPO are the control of signal transduction pathways that include protein kinase B, the mechanistic target of rapamycin, Wnt signaling, mammalian forkhead transcription factors of the O class, silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae), and AMP activated protein kinase. Therapeutic strategies that can specifically target and control EPO and its signaling pathways hold great promise for the development of new and effective clinical treatments for DM and the complications of this disorder.

New Insights for Oxidative Stress and Diabetes Mellitus

The release of reactive oxygen species (ROS) and the generation of oxidative stress are considered critical factors for the pathogenesis of diabetes mellitus (DM), a disorder that is growing in prevalence and results in significant economic loss. New therapeutic directions that address the detrimental effects of oxidative stress may be especially warranted to develop effective care for the millions of individuals that currently suffer from DM. The mechanistic target of rapamycin (mTOR), silent mating type information regulation 2 homolog 1 (S. cerevisiae) (SIRT1), and Wnt1 inducible signaling pathway protein 1 (WISP1) are especially justified to be considered treatment targets for DM since these pathways can address the complex relationship between stem cells, trophic factors, impaired glucose tolerance, programmed cell death pathways of apoptosis and autophagy, tissue remodeling, cellular energy homeostasis, and vascular biology that greatly impact the biology and disease progression of DM. The translation and development of these pathways into viable therapies will require detailed understanding of their proliferative nature to maximize clinical efficacy and limit adverse effects that have the potential to lead to unintended consequences.

Novel applications of trophic factors, Wnt and WISP for neuronal repair and regeneration in metabolic disease

Diabetes mellitus affects almost 350 million individuals throughout the globe resulting in significant morbidity and mortality. Of further concern is the growing population of individuals that remain undiagnosed but are susceptible to the detrimental outcomes of this disorder. Diabetes mellitus leads to multiple complications in the central and peripheral nervous systems that include cognitive impairment, retinal disease, neuropsychiatric disease, cerebral ischemia, and peripheral nerve degeneration. Although multiple strategies are being considered, novel targeting of trophic factors, Wnt signaling, Wnt1 inducible signaling pathway protein 1, and stem cell tissue regeneration are considered to be exciting prospects to overcome the cellular mechanisms that lead to neuronal injury in diabetes mellitus involving oxidative stress, apoptosis, and autophagy. Pathways that involve insulin-like growth factor-1, fibroblast growth factor, epidermal growth factor, and erythropoietin can govern glucose homeostasis and are intimately tied to Wnt signaling that involves Wnt1 and Wnt1 inducible signaling pathway protein 1 (CCN4) to foster control over stem cell proliferation, wound repair, cognitive decline, β-cell proliferation, vascular regeneration, and programmed cell death. Ultimately, cellular metabolism through Wnt signaling is driven by primary metabolic pathways of the mechanistic target of rapamycin and AMP activated protein kinase. These pathways offer precise biological control of cellular metabolism, but are exquisitely sensitive to the different components of Wnt signaling. As a result, unexpected clinical outcomes can ensue and therefore demand careful translation of the mechanisms that govern neural repair and regeneration in diabetes mellitus.

mTOR: Driving apoptosis and autophagy for neurocardiac complications of diabetes mellitus

The World Health Organization estimates that diabetes mellitus (DM) will become the seventh leading cause of death during the next two decades. DM affects approximately 350 million individuals worldwide and additional millions that remain undiagnosed are estimated to suffer from the complications of DM. Although the complications of DM can be seen throughout the body, the nervous, cardiac, and vascular systems can be significantly affected and lead to disorders that include cognitive loss, stroke, atherosclerosis, cardiac failure, and endothelial stem cell impairment. At the cellular level, oxidative stress is a significant determinant of cell fate during DM and leads to endoplasmic reticulum stress, mitochondrial dysfunction, apoptosis, and autophagy. Multiple strategies are being developed to combat the complications of DM, but it is the mechanistic target of rapamycin (mTOR) that is gaining interest in drug development circles especially for protective therapies that involve cytokines and growth factors such as erythropoietin. The pathways of mTOR linked to mTOR complex 1, mTOR complex 2, AMP activated protein kinase, and the hamartin (tuberous sclerosis 1)/tuberin (tuberous sclerosis 2) complex can ultimately influence neuronal, cardiac, and vascular cell survival during oxidant stress in DM through a fine interplay between apoptosis and autophagy. Further understanding of these mTOR regulated pathways should foster novel strategies for the complications of DM that impact millions of individuals with death and disability.

FoxO Transcription Factors and Regenerative Pathways in Diabetes Mellitus

Mammalian forkhead transcription factors of the O class (FoxO) are exciting targets under consideration for the development of new clinical entities to treat metabolic disorders and diabetes mellitus (DM). DM, a disorder that currently affects greater than 350 million individuals globally, can become a devastating disease that leads to cellular injury through oxidative stress pathways and affects multiple systems of the body. FoxO proteins can regulate insulin signaling, gluconeogenesis, insulin resistance, immune cell migration, and cell senescence. FoxO proteins also control cell fate through oxidative stress and pathways of autophagy and apoptosis that either lead to tissue regeneration or cell demise. Furthermore, FoxO signaling can be dependent upon signal transduction pathways that include silent mating type information regulation 2 homolog 1 (S. cerevisiae) (SIRT1), Wnt, and Wnt1 inducible signaling pathway protein 1 (WISP1). Cellular metabolic pathways driven by FoxO proteins are complex, can lead to variable clinical outcomes, and require in-depth analysis of the epigenetic and post-translation protein modifications that drive FoxO protein activation and degradation.

Programming apoptosis and autophagy with novel approaches for diabetes mellitus

According to the World Health Organization, diabetes mellitus (DM) in the year 2030 will be ranked the seventh leading cause of death in the world. DM impacts all systems of the body with oxidant stress controlling cell fate through endoplasmic reticulum stress, mitochondrial dysfunction, alterations in uncoupling proteins, and the induction of apoptosis and autophagy. Multiple treatment approaches are being entertained for DM with Wnt1 inducible signaling pathway protein 1 (WISP1), mechanistic target of rapamycin (mTOR), and silent mating type information regulation 2 homolog) 1 (S. cerevisiae) (SIRT1) generating significant interest as target pathways that can address maintenance of glucose homeostasis as well as prevention of cellular pathology by controlling insulin resistance, stem cell proliferation, and the programmed cell death pathways of apoptosis and autophagy. WISP1, mTOR, and SIRT1 can rely upon similar pathways such as AMP activated protein kinase as well as govern cellular metabolism through cytokines such as EPO and oral hypoglycemics such as metformin. Yet, these pathways require precise biological control to exclude potentially detrimental clinical outcomes. Further elucidation of the ability to translate the roles of WISP1, mTOR, and SIRT1 into effective clinical avenues offers compelling prospects for new therapies against DM that can benefit hundreds of millions of individuals throughout the globe.

β-Blocker carvedilol protects cardiomyocytes against oxidative stress-induced apoptosis by up-regulating miR-133 expression

Oxidative stress is a causal factor and key promoter of a variety of cardiovascular diseases associated with apoptotic cell death by causing deregulation of related genes. Though carvedilol, a β-adrenergic blocker, has been shown to produce cytoprotective effects against cardiomyocyte apoptosis, the mechanisms are not fully understood. The present study was designed to investigate whether the beneficial effects of carvedilol are related to microRNAs which have emerged as critical players in cardiovascular pathophysiology via post-transcriptional regulation of protein-coding genes. In vivo, we demonstrated that carvedilol ameliorated impaired cardiac function of infarct rats and restored miR-133 expression. In vitro, carvedilol protected cardiomyocytes from H2O2 induced apoptosis detected by TUNEL staining and MTT assays, and increased miR-133 expression in cardiomyocytes. Overexpression of miR-133, a recognized anti-apoptotic miRNA, produced similar effects to carvedilol: reduction of reactive oxygen species (ROS) and malondialdehyde (MDA) content and increment of superoxide dismutase (SOD) activity and glutathione peroxidase (GPx) level, so as to protect cardiomyocytes from apoptosis by downregulating caspase-9 and caspase-3 expression in the presence of H2O2. Transfection with AMO-133 (antisense inhibitor oligodeoxyribonucleotides) alone abolished the beneficial effects of carvedilol. Caspase-9-specific inhibitor z-LEHD-fmk, caspase-3-specific inhibitor z-DEVD-fmk, caspase-9 siRNA and caspase-3 siRNA were used to establish caspase-3 as a downstream target of miR-133. In conclusion, our data indicated that carvedilol protected cardiomyocytes by increasing miR-133 expression and suppressing caspase-9 and subsequent apoptotic pathways.