Application of Nanomaterials in Stem Cell-Based Therapeutics for Cardiac Repair and Regeneration.

Cardiovascular disease is a leading cause of disability and death worldwide. Although the survival rate of patients with heart diseases can be improved with contemporary pharmacological treatments and surgical procedures, none of these therapies provide a significant improvement in cardiac repair and regeneration. Stem cell-based therapies are a promising approach for functional recovery of damaged myocardium. However, the available stem cells are difficult to differentiate into cardiomyocytes, which result in the extremely low transplantation efficiency. Nanomaterials are widely used to regulate the myocardial differentiation of stem cells, and play a very important role in cardiac tissue engineering. This study discusses the current status and limitations of stem cells and cell-derived exosomes/micro RNAs based cardiac therapy, describes the cardiac repair mechanism of nanomaterials, summarizes the recent advances in nanomaterials used in cardiac repair and regeneration, and evaluates the advantages and disadvantages of the relevant nanomaterials. Besides discussing the potential clinical applications of nanomaterials in cardiac therapy, the perspectives and challenges of nanomaterials used in stem cell-based cardiac repair and regeneration are also considered. Finally, new research directions in this field are proposed, and future research trends are highlighted.

Profilin-1 promotes the development of hypertension-induced cardiac hypertrophy.

OBJECTIVE: Cardiac hypertrophy is a major cause of heart failure and sudden cardiac death among hypertensive individuals. The present study examined the effects of profilin-1 on hypertension-induced cardiac hypertrophy. METHODS: We used adenovirus injection to knockdown or overexpress profilin-1 in spontaneous hypertensive rats (SHRs). As a control, blank adenovirus was injected into age-matched SHRs and Wistar-Kyoto rats (WKYs). SBP and cardiac mass index were measured. Cardiac tissues were stained with hematoxylin-eosin and sirius red, and cardiac ultrastructure was imaged using transmission electron microscopy. Actin filament was quantified by staining with TRIC-tagged phalloidin. Caveolin-3 abundance and endothelial nitric oxide synthase (eNOS) activity were measured using real-time quantitative PCR, Western blot or immunofluorescence staining. RESULTS: Endogenous profilin-1 was highly expressed in hypertrophic myocardium of SHRs compared with WKYs. Lowering profilin-1 expression in SHRs significantly attenuated hypertension-induced cardiac hypertrophy and fibrosis and displayed a significant preservation of myofibrils, sarcolemmal caveolae, abundance of caveolin-3 protein, activity of eNOS and production of nitric oxide (NO). In contrast, transgenic overexpression of profilin-1 in SHRs induced more serious cardiac hypertrophy and fibrosis with significant reduction of sarcolemmal caveolae, caveolin-3 protein, eNOS activity, and production of NO when compared with SHR controls. CONCLUSION: Profilin-1 promotes cardiac hypertrophy partly through interfering with the formation of sarcolemmal caveolae and attenuating the eNOS/NO pathway. These results demonstrate a crucial role for profilin-1 in hypertensive cardiac hypertrophy.

Effect of ouabain on myocardial ultrastructure and cytoskeleton during the development of ventricular hypertrophy.

The aim of this work is to study cytoskeletal impairment during the development of ouabain-induced ventricular hypertrophy. Male Sprague-Dawley rats were treated with either ouabain or saline. Systolic blood pressure (SBP) was recorded weekly. At the end of the 3rd and 6th week, the rats were killed and cardiac mass index were measured. Hematoxylin-eosin and Sirius red staining were carried out and cardiac ultrastructure were studied using transmission electron microscopy. The mRNA level of Profilin-1, Desmin, PCNA, TGF-ß(1) and ET-1 in the left ventricle were measured using real-time quantitative PCR while their protein levels were examined by Western blot or immunohistochemistry. After 3 weeks, there was no significant difference in the mean SBP, cardiac mass index, mRNA and protein expression of PCNA, TGF-ß(1) and ET-1 between the two groups. However, ouabain-treated rats showed disorganized cardiac cytoskeleton with abnormal expression of Profilin-1 and Desmin. After 6 weeks, the cardiac mass index remained the same in the two groups while PCNA, TGF-ß(1), and ET-1 have been upregulated in ouabain-treated rats. The cardiac cytoskeletal impairment was more severe in ouabain-treated rats with further changes of Profilin-1 and Desmin. Cytoskeletal abnormality is an ultra-early change during ouabain-induced ventricular hypertrophy, before the release of hypertrophic factors. Therapy for prevention of ouabain-induced hypertrophy should start at the early stage by preventing the cytoskeleton from disorganization.

Effects of phlorizin on vascular complications in diabetes db/db mice.

BACKGROUND: Diabetic macrovascular complications are important causes of cardiovascular and cerebrovascular diseases and also one of the major causes of morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). Phlorizin has been reported to be effective in reducing the blood glucose level in diabetic mellitus, while little is known about its effects on vascular complications. This study aimed to observe the effects of phlorizin on the aorta of diabetes db/db mice and explore its mechanism. METHODS: Diabetic db/db mice (n = 16) and age-matched db/m mice (n = 8) were divided into three groups: normal control group (CC group, db/m mice, n = 8), untreated diabetic group (DM group, db/db mice, n = 8) and diabetic group treated by phlorizin (DMT group, db/db mice, n = 8). Phlorizin (20 mg/kg body weight) was given in normal saline solution intragastrically for 10 weeks. Animals were weighed weekly. At the 10th weekend, all mice were fasted overnight and then sacrificed. Fasting blood was collected, and the aortas were dissected. The blood samples were analyzed for fasting blood glucose (FBG), serum advanced glycation end products (AGEs), malondialdehyde (MDA) and superoxide dismutase (SOD) activity, the aortic ultrastructure was studied. RESULTS: The weight and serum concentration of FBG, AGEs, and MDA in the DM group were higher than that in the CC group (P < 0.01), and they were significantly lower in the DMT group (P < 0.05). Serum SOD activity was lower than that in the CC group (P < 0.01), and it is significantly higher in the DMT group (P < 0.05). The severity of aorta damage in the DMT group was less than that in the DM group. CONCLUSIONS: Phlorizin protected the db/db mice from diabetic macrovascular complications, attributed to the decreasing of blood glucose and AGEs level, and its antioxidant potential. This study may provide a new natural medicine for treating diabetic macrovascular complications.

The correlation between carotid-femoral pulse wave velocity and composition of the aortic media in CAD patients with or without hypertension.

OBJECTIVES: To investigate the influence of hypertension on large artery elasticity and the microstructure of the ascending aortic media in patients with coronary artery disease (CAD), and the association between arterial compliance and composition of the ascending aorta. METHODS: 60 patients with CAD who underwent coronary artery bypass graft surgery were divided into two groups: 30 patients in a hypertension group and 30 patients in a non-hypertension group. Carotid-femoral pulse wave velocity (cfPWV) was measured by an automatic device (Complior, Artech, France). The severity of coronary atherosclerosis was assessed after selective coronary angiography using the Gensini score system. A quantitative study was conducted on ascending aorta specimens by histological and computer image analysis. RESULTS: cfPWV of the hypertension group was higher than that of the non-hypertension group. The relative content of collagen in the ascending aortic media of the hypertension group was higher than that of the non-hypertension group, while the relative content of elastin in the ascending aortic media of the hypertension group was lower than that of the non-hypertension group. cfPWV showed a positive correlation with relative contents of collagen in the ascending aorta and a negative correlation with relative contents of elastin in the ascending aorta in the two groups. CONCLUSIONS: Hypertension may raise the contents of collagen and decrease the contents of elastin in the ascending aortic media of patients with CAD, which in turn may decrease the patients' large artery compliance. cfPWV may reflect the quantitative changes of collagen and elastin in the ascending aortic media in CAD patients independently of hypertension.

[Roles of monocyte chemoattractant protein-1, RANTES and Fractalkine on promoting vulnerability of atherosclerotic plaques].

OBJECTIVE: To elucidate the roles of monocyte chemotactic factors (MCP-1, RANTES and Fractalkine) on the vulnerability of atherosclerotic plaques in patients with stable (SAP) and unstable angina pectoris (UAP). METHODS: Patients with SAP (n = 50) and UAP (n = 50) underwent coronary angiography (CAG) and intravenous ultrasound (IVUS) were included in the study. Monocyte chemotaxis was assayed by the transwell chamber. Concentrations of hs-CRP, MCP-1, RANTES and Fractalkine were measured by Enzyme-linked-immunosorbent assay (ELISA). mRNA expression of MCP-1, RANTES and Fractalkine in the monocytes was detected by RT-PCR. RESULTS: IVUS evidenced soft lipid plaques in 48% UAP patients and in 16% SAP patients (P < 0.05). SAP patients had mainly fibrous and mixed plaques. Plaque burden and vascular remodeling index were significantly higher in UAP patients than in SAP patients (P < 0.01). The averaged number of migrated monocytes in the UAP patients were higher than that in patients with SAP (P < 0.01). Concentration of hs-CRP, MCP-1, RANTES and Fractalkine were significantly higher in UAP patients than those of SAP patients (P < 0.05 or P < 0.01). mRNA expression of MCP-1, RANTES and Fractalkine in patients with UAP was significantly higher than those of SAP patients (P < 0.05). CONCLUSION: Upregulated monocyte chemotactic factors (MCP-1, RANTES and Fractalkine) might promote coronary plaque vulnerability in UAP patients.

Vascular compliance is reduced in geriatric people with angiographic coronary atherosclerosis.

This study investigated the value of arterial elasticity measurement in the early diagnosis of angiographic coronary artery atherosclerosis in 105 consecutive elderly patients. They were divided into two groups according to the results of selective coronary angiography: 55 with coronary atherosclerosis and 50 with a normal coronary angiogram. The Gensini score of the coronary artery was acquired and capacitive arterial compliance (C1) and oscillatory arterial compliance (C2) were measured. An independent-sample t-test was used to evaluate the difference in C1 and C2 between the two groups. Bivariate analyses were performed to study the association between the Gensini score and C1 and C2. A significant difference between the two groups in C2 was found and the Gensini score of the coronary artery was significantly correlated with C2. Identification of early coronary atherosclerosis in geriatrics may be aided by the prognostic value of C2.

Safety and efficacy of transcatheter closure of atrial septal defects guided by transthoracic echocardiography: a prospective study from two Chinese Medical Centers.

The purpose of this study was to evaluate the safety and efficacy of transcatheter atrial septal defect (ASD) closure guided by transthoracic echocardiography (TTE). A total of 191 patients with ASD were recruited from two Chinese medical centers and TTE was carefully performed in multiple views to observe ASD number, position, diameter and relation with adjacent cardiac structures. All patients were divided into three groups based on their largest ASD diameters: 66 subjects with ASD diameter 5-14 mm (group A); 60 subjects with ASD diameter 15-20 mm (group B); and 65 subjects with ASD diameter 21-38 mm (group C). Atrial septal occluders (ASOs) were successfully deployed in 188 patients (98.4%) and ASD was successfully closed at 6-mo follow-up in 185 patients (96.9%). The difference between diameters of ASO and ASD (ASO-ASD) in groups A, B and C were 3.9 +/- 2.4 (0-7) mm, 5.0 +/- 2.6 (3-8) mm and 6.2 +/- 3.8 (5-11) mm, respectively. In group A, no complications occurred. In group B, only four patients had mild complications such as sinus bradycardia, transient hematuria and migraine, all of which disappeared after treatment. In group C, one patient developed ASO migration into the right atrium and two patients had their ASO migrated into the right ventricular outflow tract. Immediately after the closure, 60 (90.9%), 53 (88.3%) and 53 (82.8%) patients had complete ASD closure; 2, 4 and 6 patients had trivial residual shunts; 4, 3 and 2 patients had small residual shunts; and 0, 0 and 2 patients had moderate residual shunts in groups A, B and C, respectively. Most of the residual shunts were persistent at 6-mo follow-up. No embolism or death at procedure and 6-mo follow-up occurred. In conclusion, TTE is a reliable technique for measurement of ASD diameter, guidance of transcatheter ASD closure and evaluation of residual shunts. Transcatheter ASD closure guided by TTE is safe and effective, especially in patients with ASD

Reliability of transthoracic echocardiography in estimating the size of Amplatzer septal occluder and guiding percutaneous closure of atrial septal defects.

BACKGROUND: In China, transthoracic echocardiography (TTE) is popularly used for pre-intervention examination for atrial septal defect (ASD) and for guiding ASD closure. However, the ability to determine ASD size and the safety and efficacy of TTE for guiding ASD closure still has not been widely accepted. This study aimed to evaluate the efficacy and safety of TTE used before, during and after transcatheter ASD closure with Amplatzer septal occluders (ASO). METHODS: Sixty-eight subjects (15 men and 53 women; mean age (33.7 +/- 17.3) years) were enrolled. TTE was used to measure the diameters and guide transcatheter closure of ASD. The ASD was examined by long-axis view, basal short-axis view, apical four-chamber view and the subcostal view to observe position, diameter and relation with neighbouring structures. The largest diameter was selected as the reference diameter. Patients were divided into 3 groups according to the ASD reference diameter: 22 subjects with ASD diameter 4 - 14 mm (group A); 21 subjects with ASD diameter 15 - 20 mm (group B); and 25 subjects with ASD diameter 21 - 33 mm (group C). RESULTS: ASD was occluded successfully in groups A and B. In group C, occlusion failed in 2 cases; 1 case remained with a 3-mm residual shunt sustained until 6-month follow-up. However, at 6-month follow-up, no case of thromboembolism, ASO dislocation or death occurred in the three groups. The diameter of ASD measured by TTE could accurately predict the ASO size that could successfully occlude the ASD, especially in patients with ASD < 20 mm. The ASD diameter measured by TTE correlated well with ASO size (r = 0.925, P < 0.001; r = 0.976, P < 0.001; r = 0.929, P < 0.001 respectively). CONCLUSIONS: ASD diameter measured by TTE can accurately estimate the size of the ASO needed for successful closure of ASD. The larger the ASD, the much larger the ASO needed. TTE is a satisfactory guiding imaging tool for ASD closure.

Back-regulation of six oxidative stress proteins with grape seed proanthocyanidin extracts in rat diabetic nephropathy.

Diabetic nephropathy (DN) is a major cause of morbidity and mortality in diabetic patients. To prevent the development of this disease and to improve advanced kidney injury, effective therapies directed toward the key molecular target are required. Grape seed proanthocyanidin extracts (GSPE) have been reported to be effective in treating DN, while little is known about the functional protein changes. In this study, we used streptozotocin (STZ) to induce diabetic rats. GSPE (250 mg/kg body weight/day) were administrated to diabetic rats for 24 weeks. Serum glucose, glycated hemoglobin, and advanced glycation end products were determined. Consequently, 2-D difference gel electrophoresis and mass spectrometry were used to investigate kidney protein profiles among the control, untreated and GSPE treated diabetic rats. Twenty-five proteins were found either up-regulated or down-regulated in the kidneys of untreated diabetic rats. Only nine proteins in the kidneys of diabetic rats were found to be back-regulated to normal levels after GSPE therapy. These back-regulated proteins are involved in oxidative stress, glycosylation damage, and amino acids metabolism. Our findings might help to better understanding of the mechanism of DN, and provide novel targets for estimating the effects of GSPE therapy.

Grape seed proanthocyanidin extracts inhibit vascular cell adhesion molecule expression induced by advanced glycation end products through activation of peroxisome proliferators-activated receptor gamma.

Although evidence has shown that grape seed proanthocyanidin extracts (GSPE) can selectively inhibit cell adhesion molecule expression induced by advanced glycation end products (AGEs), the underlying molecular mechanism has not been extensively characterized. To study the antiinflammation mechanism of GSPE, we investigated the effect of GSPE on Von Willebrand factor (vWF) content and the expression of vascular cell adhesion molecule-1 (VCAM-1) induced by AGEs and the effect of GSPE on peroxisome proliferators-activated receptor gamma (PPAR gamma) and receptor for AGEs (RAGE) expression in human umbilical vein endothelial cells (HUVEC). HUVEC were preincubated with or without GSPE of different concentrations (10 mg/L, 50 mg/L, and 100 mg/L) for 4 hours before being treated with 200 mg/L AGEs or unmodified bovine serum albumin (BSA) for 24 hours. The expression of RAGE and PPAR gamma was investigated by Western blot. VCAM-1 expression was measured by flow cytometry and vWF content by enzyme-linked immunosorbent assay (ELISA). Results showed that GSPE significantly inhibited the expression of VCAM-1 in HUVEC and reduced the content of vWF in culture fluid induced by AGEs in a dose-dependent manner. AGEs activated the expression of RAGE and inhibited PPAR gamma expression in HUVEC, whereas GSPE inhibited the expression of RAGE through activation of PPAR gamma in HUVEC simultaneously. These findings indicated that GSPE inhibited the cell inflammatory factor expression and protected the function of endothelial cell through activation of PPAR gamma expression and inhibition of RAGE expression.

Proteomics analysis of the proliferative effect of low-dose ouabain on human endothelial cells.

Digitalis has been used to treat congestive heart failure for more than 200 years, although the dual effects (proliferation and death) induced by digitalis on cell growth have been known for many years, the mechanisms by which digitalis causes the actions were not completely known. The aim of this work was to characterize the proliferative effect of ouabain on cell growth in endothelial cells, and, to do the differential proteomic analysis of human umbilical vein endothelial cells (HUVEC) in response to ouabain and examine changes in protein expression. HUVEC were exposed to different concentrations (0.1-100 nM) of ouabain at 12-48 h intervals. Cell growth and morphological changes of HUVEC treated with ouabain were compared with cells under nontreated conditions. Ouabain stimulated HUVEC cell proliferation at low concentrations and induced cell death at higher concentrations. Using proteomics study, we identified 32 proteins of HUVEC with various important cellular functions and revealed 8 proteins such as Annexin A1, Annexin A2, Malate dehydrogenase, Myosin regulatory light chain 2 (MRLC2), Profilin-1, S100 calcium-binding protein A13, Triosephosphate isomerase and Translationally controlled tumor protein, regulated by low-dose ouabain treatment and MRLC2 was subsequently confirmed by Western blot. Our results give new insights into the cellular and molecular mechanisms of the proliferation action of low-dose ouabain on HUVEC and provide new avenues for the treatment of cardiovascular diseases.

Selective inhibition by grape seed proanthocyanidin extracts of cell adhesion molecule expression induced by advanced glycation end products in endothelial cells.

The interaction of advanced glycation end products (AGE) with their cell surface receptors for AGEs (RAGE) has been causally implicated in the pathogenesis of diabetic vascular complications and has been shown to stimulate cell adhesion molecule expression in endothelial cells via induction of reactive oxygen species (ROS). Alternatively, grape seed proanthocyanidin extracts (GSPE), which are naturally occurring polyphenolic compounds, have been reported to possess potent radical scavenging and antioxidant properties and to display significant cardiovascular protective action. In this study, we investigated whether GSPE could inhibit AGE-induced cell adhesion molecule expression through interference with ROS generations in human umbilical vein endothelial cells. AGE-modified bovine serum albumin (AGE-BSA) was prepared by incubating BSA with a high concentration of glucose. Stimulation of cultured human umbilical vein endothelial cells with 200 microg/mL of AGE-BSA significantly enhanced intracellular ROS formation and subsequently upregulated the expression of vascular cell adhesion molecule-1 (VCAM) and intercellular adhesion molecule-1 (ICAM-1), whereas both unmodified BSA and GSPE alone were without effect. However, preincubation of different concentrations of GSPE markedly downregulated AGE-BSA-induced VCAM-1 expression at the surface protein and mRNA level in a concentration-dependent manner, but the increased ICAM-1 expression was not affected by GSPE treatment. Meanwhile, the inhibition by GSPE of intracellular ROS generation was also observed at defined time periods. These results demonstrate that GSPE can inhibit the enhanced VCAM-1 expression but not ICAM-1 in AGE-exposed endothelial cells by suppressing ROS generation. Hence, GSPE may have therapeutic potential in the prevention and treatment of vascular complications in patients with diabetes.