Neuroprotective strategies, including free radical scavengers, ion channel modulators, and anti-inflammatory agents, have been extensively explored in the last 2 decades for the treatment of neurological diseases. Unfortunately, none of the neuroprotectants has been proved effective in clinical trails. In the current study, we demonstrated that methylene blue (MB) functions as an alternative electron carrier, which accepts electrons from NADH and transfers them to cytochrome c and bypasses complex I/III blockage. A de novo synthesized MB derivative, with the redox center disabled by N-acetylation, had no effect on mitochondrial complex activities. MB increases cellular oxygen consumption rates and reduces anaerobic glycolysis in cultured neuronal cells. MB is protective against various insults in vitro at low nanomolar concentrations. Our data indicate that MB has a unique mechanism and is fundamentally different from traditional antioxidants. We examined the effects of MB in two animal models of neurological diseases. MB dramatically attenuates behavioral, neurochemical, and neuropathological impairment in a Parkinson disease model. Rotenone caused severe dopamine depletion in the striatum, which was almost completely rescued by MB. MB rescued the effects of rotenone on mitochondrial complex I-III inhibition and free radical overproduction. Rotenone induced a severe loss of nigral dopaminergic neurons, which was dramatically attenuated by MB. In addition, MB significantly reduced cerebral ischemia reperfusion damage in a transient focal cerebral ischemia model. The present study indicates that rerouting mitochondrial electron transfer by MB or similar molecules provides a novel strategy for neuroprotection against both chronic and acute neurological diseases involving mitochondrial dysfunction.

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Ator treatment may protect the myocardium undergoing acute infarction and reperfusion by creating a better environment for the survival and differentiation of implanted MSCs. The benefit of the Ator/stem cell combined therapy may result from the statin-mediated inhibition of apoptosis, oxidative stress, and inflammation in the infarcted myocardium.

The objective of the present study was to investigate whether pretreatment with single low loading dose of tongxinluo (TXL), a traditional Chinese medicine, 1 h before myocardial ischemia could attenuate no-reflow and ischemia-reperfusion injury by regulating endothelial nitric oxide synthase (eNOS) via the PKA pathway. In a 90-min ischemia and 3-h reperfusion model, minipigs were randomly assigned to the following groups: sham, control, TXL (0.05 g/kg, gavaged 1 h before ischemia), TXL + H-89 (a PKA inhibitor, intravenously infused at a dose of 1.0 μg·kg(-1)·min(-1) 30 min before ischemia), and TXL + N(ω)-nitro-L-arginine (L-NNA; an eNOS inhibitor, intravenously administered at a dose of 10 mg/kg 30 min before ischemia). TXL decreased creatine kinase (CK) activity (P < 0.05) and reduced the no-reflow area from 48.6% to 9.5% and infarct size from 78.5% to 59.2% (P < 0.05), whereas these effects of TXL were partially abolished by H-89 and completely reversed by L-NNA. TXL elevated PKA activity and the expression of PKA, Thr(198) phosphorylated PKA, Ser(1179) phosphorylated eNOS, and Ser(635) phosphorylated eNOS in the ischemic myocardium. H-89 repressed the TXL-induced enhancement of PKA activity and phosphorylation of eNOS at Ser(635), and L-NNA counteracted the phosphorylation of eNOS at Ser(1179) and Ser(635) without an apparent influence on PKA activity. In conclusion, pretreatment with a single low loading dose of TXL 1 h before ischemia reduces myocardial no-reflow and ischemia-reperfusion injury by upregulating the phosphorylation of eNOS at Ser(1179) and Ser(635), and this effect is partially mediated by the PKA pathway.

BackgroundIn a swine model of acute myocardial infarction (AMI), Statins can enhance the therapeutic efficacy of mesenchymal stem cell (MSCs) transplantation. However, the mechanisms remain unclear. This study aims at assessing whether atorvastatin (Ator) facilitates the effects of MSCs through activation of nitric oxide synthase (NOS), especially endothelial nitric oxide synthase (eNOS), which is known to protect against ischemic injury.Methods and Results42 miniswines were randomized into six groups (n = 7/group): Sham operation; AMI control; Ator only; MSC only, Ator+MSCs and Ator+MSCs+NG-nitrol-L-arginine (L-NNA), an inhibitor of NOS. In an open-heart surgery, swine coronary artery ligation and reperfusion model were established, and autologous bone-marrow MSCs were injected intramyocardium. Four weeks after transplantation, compared with the control group, Ator+MSCs animals exhibited decreased defect areas of both “perfusion” defined by Single-Photon Emission Computed Tomography (−6.2±1.8% vs. 2.0±5.1%, P = 0.0001) and “metabolism” defined by Positron Emission Tomography (−3.00±1.41% vs. 4.20±4.09%, P = 0.0004); Ejection fraction by Magnetic Resonance Imaging increased substantially (14.22±12.8% vs. 1.64±2.64%, P = 0.019). In addition, indices of inflammation, fibrosis, and apoptosis were reduced and survivals of MSCs or MSC-derived cells were increased in Ator+MSCs animals. In Ator or MSCs alone group, perfusion, metabolism, inflammation, fibrosis or apoptosis were reduced but there were no benefits in terms of heart function and cell survival. Furthermore, the above benefits of Ator+MSCs treatment could be partially blocked by L-NNA.ConclusionsAtorvastatin facilitates survival of implanted MSCs, improves function and morphology of infarcted hearts, mediated by activation of eNOS and alleviated by NOS inhibitor. The data reveal the cellular and molecular mechanism for anti-AMI therapy with a combination of statin and stem cells.

Aims Cardiac complications are common and associated with mortality in critically ill patients with COVID-19; however, the diagnostic and prognostic implications of critical care echocardiography (CCE) have not been studied. Methods and results A cohort of 43 patients with COVID-19 who were in the intensive care unit (ICU) underwent bedside CCE during their disease course. Demographic, clinical, and survival data were collected. The echocardiographic analyses revealed high frequencies of pericardial effusion (90.7%), increased left ventricular mass index (60.5%), elevated relative wall thickness (76.7%), and reduced left ventricular stroke volume index (LVSVi; 53.5%) and cardiac index (51.2%). Twenty-two (51.2%) patients died in the ICU. In multivariate Cox regression, the strongest predictor of in-ICU death was decreased cardiac index [hazard ratio (HR), 0.67, 95% confidence interval (CI), 0.45-0.98; P = 0.041], after adjusting for male sex, shock status, high-sensitivity cardiac troponin I, and N-terminal pro-B-type natriuretic peptide. Negative associations with mortality were observed for LVSVi (HR, 0.91, 95% CI 0.85-0.96; P = 0.002), tricuspid annular plane systolic excursion (HR, 0.74, 95% CI 0.64-0.84; P < 0.001), and S′ (HR, 0.78, 95% CI 0.69-0.88; P < 0.001). Kaplan-Meier analyses indicated that reductions in LVSVi, cardiac index, TAPSE, and S′ were associated with a shorter survival time. Conclusions Pericardial effusion and increased ventricular mass in COVID-19 might indicate a swollen heart. Both left and right heart dysfunction and a reduced cardiac index may lead to an increased risk of mortality. Clinicians should pay special attention to cardiac haemodynamic disorders in critical patients with COVID-19.

Objective-Widespread death of implanted cells hampers stem cell therapy for acute myocardial infarction (AMI). Based on the pleiotropic beneficial effects of statins, we examined whether simvastatin (SIMV) increased the efficacy of mesenchymal stem cell (MSC) transplantation after AMI. Methods and Results-Chinese miniswine (nϭ28) were randomized to 1 of 4 groups (nϭ7 per group): control, SIMV (0.25 mg/kg ⅐ d), MSC transplantation, and SIMVϩMSCs. AMI was created by ligating the left anterior descending coronary artery; MSCs were injected immediately into the cyanotic myocardium. At 6 weeks, MRI showed the number of dyskinetic segments and the infarct size were significantly decreased in the SIMV group. Cardiac function improved and the perfusion defect decreased significantly in the SIMVϩMSC group but not in the MSC-only group (PϽ0.05, versus control group). MSC survival and differentiation were significantly better in the combination group than in the MSC-only group (PϽ0.01). Cell apoptosis decreased significantly in both the SIMV and the SIMVϩMSC groups but not in the MSC-only group when compared with controls (PϽ0.05). Furthermore, oxidative stress and inflammatory response was significantly reduced in the infarcted regions in both the SIMV and the SIMVϩMSCs groups. Conclusions-SIMV treatment improves the therapeutic efficacy of MSC transplantation in acutely infarcted hearts by promoting cell survival and cardiovascular differentiation.

Coronavirus disease-2019 (COVID-19), caused by SARS-CoV-2, has rapidly spread to most of countries in the world, threatening the health and lives of many people. Unfortunately, information regarding the immunological characteristics in COVID-19 patients remains limited. Here we collected the blood samples from 18 healthy donors (HD) and 38 COVID-19 patients to analyze changes in the adaptive immune cell populations and phenotypes. In comparison to HD, the lymphocyte percentage was slightly decreased, the percentages of CD4 and CD8 T cells in lymphocytes are similar, whereas B cell percentage increased in COVID-19 patients. T cells, especially CD8 T cells, showed an enhanced expression of late activation marker CD25 and exhaustion marker PD-1. Importantly, SARS-CoV-2 induced an increased percentage of T follicular helpher (Tfh)- and germinal center B-like (GCB-like) cells in the blood. However, the parameters in COVD-19 patients remained unchanged across various age groups. Therefore, we demonstrated that the T and B cells can be activated normally and exhibit functional features. These data provide a clue that the adaptive immunity in most people could be primed to induce a significant immune response against SARS-CoV-2 infection upon receiving standard medical care.