Correction: Ultrasensitive fluorescent aptasensor for CRP detection based on the RNase H assisted DNA recycling signal amplification strategy.

[This corrects the article DOI: 10.1039/C9RA01352K.].

Ultrasensitive fluorescent aptasensor for CRP detection based on the RNase H assisted DNA recycling signal amplification strategy.

An aptamer-based method for the ultrasensitive fluorescence detection of C-reactive protein (CRP) was developed using the ribonuclease H (RNase H) assisted DNA recycling signal amplification strategy. In this assay, CRP can specifically bind to the aptamer of CRP and the DNA chain of P1 is released from the aptamer/P1 (Ap/P1) complexes. After the addition of the fluorescence labeled (5-FAM) RNA, P1 hybridizes with fluorescence labeled RNA to form a P1/RNA double strand. When RNase H is added, the RNA with fluorescence labeling in the double strand is specifically cut into nucleotide fragments, which cannot be adsorbed on the surface of the GO, so as to generate a fluorescence signal. In the absence of CRP, fluorescence labeled RNA cannot hybridize with P1 to form double strands, which is able to directly adsorb on the surface of GO, resulting in no fluorescence signal. The detection limit is as low as 0.01 ng mL-1, with a linear dynamic range from 50 pg mL-1 to 100 ng mL-1. This sensor is able to detect CRP in spiked human serum, urine and saliva. Thus, it shows a great application prospect in disease diagnosis and prognosis.

Promoter DNA demethylation of Keap1 gene in diabetic cardiomyopathy.

Researches have shown that the onset of diabetes is closely associated with oxidative stress and the chronic exposure leads to the development of complications such as diabetic cardiomyopathy. One of the central adaptive responses against the oxidative stresses is the activation of the nuclear transcriptional factor, NF-E2-related factor 2 (Nrf2), which then activates more than 20 different antioxidative enzymes. Kelch-like ECH associated protein 1 (Keap1) targets and binds to Nrf2 for proteosomal degradation. The aim of the present study was to investigate the status of Nrf2 mediated antioxidant system in myocardial biopsies of non-diabetic (NDM) and type-2 diabetic (DM-T2) cardiomyopathy patients. The western blot analysis of antioxidant proteins, real-time PCR analysis of Nrf2/Keap1 gene and bisulphate DNA sequencing analysis to study the methylation status of the CpG islands of Keap1 promoter DNA were performed. The immunoblot analysis showed the decreased level of antioxidant proteins other than Keap1 in the diabetic cardiopathy patients. Similarly, mRNA levels of Keap1 showed 5-fold increase in diabetic patients. Further analysis on promoter region of Keap1 gene revealed 80% demethylation in diabetic patients. Altogether, our results indicated that demethylation of the CpG islands in the Keap1 promoter will activate the expression of Keap1 protein, which then increases the targeting of Nrf2 for proteosomal degradation. Decreased Nrf2 activity represses the transcription of many antioxidant enzyme genes and alters the redox-balance up on diabetes. Thus, our study clearly demonstrates the failure of Nrf2 mediated antioxidant system revealed in biopsies of diabetic cardiomyopathy.

Ischemic postconditioning decreases matrix metalloproteinase-2 expression during ischemia-reperfusion of myocardium in a rabbit model: A preliminary report.

OBJECTIVE: To investigate the effect of ischemic postconditioning on the expression of matrix metalloproteinase (MMP)-2 during ischemia-reperfusion of myocardium in a rabbit model. METHODS: Thirty-six male New Zealand white rabbits were randomly divided into sham, ischemia-reperfusion and ischemic postconditioning groups. Myocardial ischemia-reperfusion was created by ligating the left anterior descending coronary artery for 30 min followed by 3 h of reperfusion. Myocardial infarction sizes were determined by dual staining with triphenyltetrazolium chloride and trypan blue. Plasma levels of MMP-2 were measured using ELISA. Myocardial MMP-2 messenger RNA was analyzed by reverse transcription polymerase chain reaction. RESULTS: The mean (± SD) infarct size in the ischemic postconditioning group was significantly smaller compared with the ischemia-reperfusion group (37.1±3.8% versus 57.5±1.9%; P=0.02). The incidence of ventricular tachycardia in the ischemic postconditioning group was also lower than in the ischemia-reperfusion group (8.5% versus 75%; P=0.003). MMP-2 messenger RNA expression in the ischemic postconditioning group was significantly lower compared with the ischemia-reperfusion group (0.4944±0.0476 versus 0.6989±0.0694; P=0.02). CONCLUSION: Ischemic postconditioning reduces myocardial ischemia-reperfusion injury, possibly by inhibiting the expression of MMP-2.

Combination of fluvastatin and losartan relieves atherosclerosis and macrophage infiltration in atherosclerotic plaques in rabbits.

AIM: To investigate whether the combination of fluvastatin and losartan synergistically relieve atherosclerosis and plaque inflammation induced by a high-cholesterol diet in rabbits. METHODS: Atherosclerosis was induced with a high-cholesterol diet for 3 months in 36 New Zealand white rabbits. The animals were randomly divided into model group, fluvastatin (10 mg·kg(-1)·d(-1)) group, losartan (25 mg·kg(-1)·d(-1)) group, and fluvastatin plus losartan group. After the 16-week treatments, the blood samples the animals were collected, and the thoracic aortas were examined immunohistochemically. The mRNA and protein expression levels of monocyte chemotactic protein-1 (MCP-1) were measured using RT-PCR and Western blot. RESULTS: Compared to the treatment with losartan or fluvastatin alone, the combined treatment did not produce higher efficacy in reduction of blood cholesterol level. However, the combination did synergistically decrease the intimal and media thickness of thoracic aortas with significantly reduced macrophage infiltration and MCP-1 expression in the plaques. CONCLUSION: The combined treatment with losartan and fluvastatin significantly inhibited atherosclerotic progress and reduced inflammation associated with atherosclerotic plaques.

[Early intervention on atherosclerosis by fluvastatin and lectin-like oxidized low-density lipoprotein receptor-1 expression in atherosclerotic arteries in immature rabbits].

OBJECTIVE: The present study was designed to investigate the preventive and therapeutic effect of 3-hydroxy-3-methylglutanyl coenzyme A (HMG-CoA) reductase inhibitor fluvastatin on the development of atherosclerosis (AS) in immature rabbits and its possible mechanism by detecting the expression level of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in the abdominal aorta. METHODS: A model of hypercholesterolemia (HC) was established by high-cholesterol diet and 24 immature rabbits were divided randomly and equally into control group, HC-diet group and fluvastatin group. At the beginning of the study and after 12 weeks, the body height (BH) and body weight (BW) of the rabbits were measured and their body mass index (BMI) was calculated. At the end of 12 weeks, serum total cholesterol (TC) and low-density lipoprotein (LDL) levels were examined. The intima-medial thickness of the abdominal aorta (aIMT) was measured by using non-invasive high-resolution (14 MHz) B-mode ultrasound imaging. Histological changes in abdominal arteries were studied by H&E-staining and histomorphometric analysis. The gene expression of LOX-1 in abdominal aorta was evaluated by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and its protein expression was examined by immunohistochemistry. RESULTS: High cholesterol diet induced hypercholesterolemia and early AS in immature rabbits. In HC-diet group serum TC and LDL levels in rabbits elevated. B mode echocardiography showed that aIMT was thickened and pathomorphology indicated that extensive aortic intima (I) and intima and media (I + M) became thickened and the ratio of the area of intima to media (S(I)/S(M)) was increased. Aortic intimal proliferation in HC-diet group was associated with a marked increase in LOX-1 expression (protein and mRNA) in endothelium and neointima of the abdominal aorta. Treatment with fluvastatin at a dosage of 10 mg/(kg.d) deduced serum lipid, attenuated artery intimal proliferation and markedly decreased the enhanced LOX-1 expression level in endothelium and neointima in immature rabbits. There were no significant differences of BH, BW or BMI among the three groups. CONCLUSIONS: These findings suggested that early treatment with fluvastatin not only induced a significant regression of arterial lesions of HC and early AS in immature rabbits, but also had a crucial endothelial protective effect by down-regulating LOX-1 expression level in atherosclerotic arteries in early AS.

Fluvastatin prevents renal injury and expression of lactin-like oxidized low-density lipoprotein receptor-1 in rabbits with hypercholesterolemia.

BACKGROUND: Lipid abnormalities are often complicated by renal dysfunction. 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are the first-line choice for lowering cholesterol levels. The present study was designed to investigate whether statins could prevent and invert the development of renal injury in cholesterol-fed rabbits and to find the possible mechanism of their effects by detecting gene and protein expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in the renal artery. METHODS: Twenty-four male New Zealand white rabbits were divided into three groups: (1) control group, regular granules chow; (2) HC-diet group, granules chow with 1% cholesterol and 5% lard oil; and (3) fluvastatin group, 1% cholesterol and 5% lard oil diet plus fluvastatin [10 mg.kg(-1).d(-1)]. After 16 weeks, serum total cholesterol (TC), low-density lipoprotein (LDL) and creatinine (Cr) levels were measured. Renal hemodynamics and function, mainly including glomerular filtration rate (GFR) in vivo were quantified using (99m)Tc-DTPA single photon emission computed tomograph ((99m)Tc-DTPA SPECT). The thickness of the renal artery intima was quantitated in HE-stained segments by histomorphometry. Gene expression of LOX-1 in the renal artery was examined by semi-quantitative RT-PCR and its protein expression was evaluated by immunohistochemistry. RESULTS: High cholesterol diet induced hypercholesterolemia (HC) complicated by renal dysfunction with increased levels of serum lipid and Cr, decreased GFR and delayed excretion and extensively thickened renal arterial intima in the HC-diet group. Rabbits in the control group showed a minimal LOX-1 expression (mRNA and protein) in the endothelium and neointima of the renal artery. Intimal proliferation of the renal artery in the HC-diet group was associated with a marked increase of LOX-1 expression (protein and mRNA). Treatment with fluvastatin improved renal function, attenuated intimal proliferation of the renal artery and markedly decreased the enhanced LOX-1 expression in the endothelium and neointima of the renal artery in rabbits. CONCLUSIONS: Fluvastatin treatment could prevent the development of renal injury in patients with HC and early atherosclerosis (AS). This beneficial effect might be mediated by its pleiotropic effects including a decrease in total cholesterol exposure level and prevention of LOX-1 expression in atherosclerotic arteries.