Since December 2019, the outbreak of pneumonia caused by a new coronavirus [1], which was later identified as coronavirus disease 2019 (COVID19), has infected more than 410,000 patients globally according to the situation report of World Health Organization. Lung ultrasound is an important tool for the diagnosis and follow-up of pneumonia in neonates, children, and adults [2][3][4]. Recent CT reports demonstrated that most of the lesions were distributed peripherally in the lung, which facilitates detection by lung ultrasound [5,6]. In this study, we characterize the lung ultrasound findings COVID-19 pneumonia, and study the relationship between the ultrasound findings and clinical severity and the time-course of disease progress. Bedside lung ultrasound was performed to detect B-lines, lung consolidation, and pleural line abnormalities at 5 areas in each lung. Vascular ultrasound was also performed to detect potential deep vein thrombosis.A total of 20 patients of COVID-19 pneumonia (12 males and 8 females) were categorized as 4 moderate, 5 severe, and 11 critical cases according to the current diagnosis and treatment program. All patients showed abnormal lung ultrasound findings, including 100% (20) pleural line abnormalities, 100% (20) B-lines, and 50% (10) consolidation. Most of the moderate and severe cases could show both separated B-lines and confluent B-lines during admission. All critical patients showed confluent Blines, and 18% (2) of them had compact B-lines. Bilateral involvement was observed in all patients. The predominate involved areas in moderate patients were on the back, i.e., the interscapular and infrascapular areas. For severe and critical patients, all 5 areas could be involved. Consolidations were not detected in moderate cases, and distributed mainly on the posterior areas in severe and critical cases. Pleural effusion (18%, 2 cases), pericardial effusion (9%, 1 case), and deep vein thrombosis (64%, 5 cases) were only found in critical patients. (Table 1).A total of 36 ultrasound examinations were categorized to four groups based on the time interval between onset of symptoms and ultrasound examinations (1st to 4th week). All of the examinations showed abnormal lung ultrasound findings, including 100% (36) pleural line abnormalities, 100% (36) B-lines, and 64% (23) consolidation. The separate B-lines were found more than half of the examinations after the 2nd week. The majority of examinations during the 2nd and 3rd weeks showed confluent B-lines. The involvement of anterior areas with B-lines decreased along with the infected time course. The lateral and back areas were always involved in all stages for B-lines. Consolidations were found in more than half examinations after the 1st week. Most of consolidation lesions confined within unilateral lung except at the 2nd week. The anterior and lateral areas were not involved of consolidations during 1st and 4th week. Consolidations were

Rationale: Exosomes are emerging as a promising drug delivery carrier. However, rapid uptake of exosomes by the mononuclear phagocyte system (MPS) remains an obstacle for drug delivery into other targeted organs, including the heart. We hypothesized that prior blocking of uptake of exosomes by the MPS would improve their delivery to the targeted organs.Methods: Exosomes were isolated from the cell culture medium. Fluorescence-labeled exosomes were tracked in vitro and in vivo by fluorescence imaging. The expression of clathrin heavy chain (Cltc), cavolin1, Pak1 and Rhoa, known genes for endocytosis, were profiled in various cell lines and organs by qPCR. The knockdown efficiency of siRNA against Cltc was analyzed by Western blotting. Exosomecontrol and exosomeblocking were constructed by encapsulating isolated exosomes with siControl or siClathrin via electroporation, while exosometherapeutic was constructed by encapsulating isolated exosomes with miR-21a. Doxorubicin-induced cardiotoxicity model was used to verify the therapeutic efficiency of the exosome-based miR-21a delivery by echocardiography.Results: Exosomes were preferentially accumulated in the liver and spleen, mainly due to the presence of abundant macrophages. Besides the well-known phagocytic effect, efficient endocytosis also contributes to the uptake of exosomes by macrophages. Cltc was found to be highly expressed in the macrophages compared with other endocytosis-associated genes. Accordingly, knockdown of Cltc significantly decreased the uptake of exosomes by macrophages in vitro and in vivo. Moreover, prior injection of exosomeblocking strikingly improved the delivery efficiency of exosomes to organs other than spleen and liver. Consistently, compared with the direct injection of exosometherapeutic, prior injection of exosomeblocking produced a much better therapeutic effect on cardiac function in the doxorubicin-induced cardiotoxicity mouse model.Conclusions: Prior blocking of endocytosis of exosomes by macrophages with exosomeblocking successfully and efficiently improves the distribution of following exosometherapeutic in targeted organs, like the heart. The established two-step exosome delivery strategy (blocking the uptake of exosomes first followed by delivery of therapeutic exosomes) would be a promising method for gene therapy.

A widely accepted dogma is that about 15-20% of cardiac output is received by the brain in healthy adults under resting conditions. However, it is unclear if the distribution of cardiac output directed to the brain alters across the adult lifespan and is modulated by sex or other hemodynamic variables. We measured cerebral blood flow/cardiac output ratio index in 139 subjects (88 women, age 21-80 years) using phase-contrast magnetic resonance imaging and echocardiography. Body mass index, cardiac systolic function (eject fraction), central arterial stiffness (carotid-femoral pulse wave velocity), arterial pressure, heart rate, physical fitness (VO max), and total brain volume were measured to assess their effects on the cardiac output-cerebral blood flow relationship. Cerebral blood flow/cardiac output ratio index decreased by 1.3% per decade associated with decreases in cerebral blood flow ( P < 0.001), while cardiac output remained unchanged. Women had higher cerebral blood flow, lower cardiac output, and thus higher cerebral blood flow/cardiac output ratio index than men across the adult lifespan. Age, body mass index, carotid-femoral pulse wave velocity, and arterial pressure all had negative correlations with cerebral blood flow and cerebral blood flow/cardiac output ratio index ( P < 0.05). Multivariable analysis adjusted for sex, age showed that only body mass index was negatively associated with cerebral blood flow/cardiac output ratio index (β = -0.33, P < 0.001). These findings demonstrated that cardiac output distributed to the brain has sex differences and decreases across the adult lifespan and is inversely associated with body mass index.

Age-related alterations in systemic and cerebral hemodynamics are not well understood. The purpose of this study is to characterize age-related alterations in beat-to-beat oscillations in arterial blood pressure (BP), heart rate (HR), cerebral blood flow (CBF), cardiac baroreflex sensitivity (BRS) and dynamic cerebral autoregulation (dCA) across the adult life span. We studied 136 healthy adults aged 21–80 years (60% women). Beat-to-beat BP, HR and CBF velocity were measured at rest and during sit-stand maneuvers to mimic effects of postural changes on BP and CBF. Transfer function analysis was used to assess BRS and dCA. Carotid-femoral pulse wave velocity (cfPWV) was measured to assess central arterial stiffness. Advanced aging was associated with elevated cfPWV, systolic and pulse BP, cerebrovascular resistance and CBF pulsatility, but reduced mean CBF velocity. Compared to the young and middle-aged, older adults had lower beat-to-beat BP, HR and CBF variability in the low frequency ranges (LF) at rest, but higher BP and CBF variability during sit-stand maneuvers. BRS was reduced, while dCA gain was elevated at rest in older adults. Multiple linear regression analysis indicated that systolic BP variability is correlated positively with cfPWV independent of HR variability. In conclusion, advanced aging is associated with elevated pulsatility in BP and CBF, reduced beat-to-beat LF oscillations in BP, HR and CBF, and impaired BRS and dCA at rest. The augmented BP and CBF variability in older adults during sit-stand maneuvers indicate diminished cardiovascular regulatory capability and increased hemodynamic stress on the cerebral circulation with aging.

BackgroundDiabetic cardiomyopathy is one of the leading causes of death in diabetes mellitus (DM) patients. This study aimed to explore the therapeutic implication of N-acetyl-L-cysteine (NAC, an antioxidant and glutathione precursor) and the possible underlying mechanism.MethodsThirty five 12-week-old male C57BL/6 mice were included. Twenty-five diabetic mice were induced by intraperitoneal injection of streptozocin (STZ, 150 mg/kg, Sigma-Aldrich) dissolved in a mix of citrate buffer after overnight fast. Mice with a blood glucose level above 13.5 mmol/L were considered diabetic. As a non-DM (diabetic) control, mice were injected with equal volume of citrate buffer. The 25 diabetic mice were divided into 5 groups with 5 animals in each group: including DM (diabetes without NAC treatment), and 4 different NAC treatment groups, namely NAC1, NAC3, NAC5 and NAC7, with the number defining the start time point of NAC treatment. In the 10 non-DM mice, mice were either untreated (Ctrl) or treated with NAC for 5 weeks (NAC only). Echocardiography was performed 12 weeks after STZ injection. Heart tissue were collected after echocardiography for Hematoxylin Eosin (HE) and Trichrome staining and ROS staining. Cardiac fibroblast cells were isolated, cultured and treated with high glucose plus NAC or the vehicle. qPCR analysis and CCK-8 assay were performed to observe fibrotic gene expression and cell proliferation.ResultsWe found that both cardiac systolic function and diastolic function were impaired, coupled with excessive reactive oxygen stress and cardiac fibrosis 12 weeks after STZ induction. NAC significantly reduced ROS generation and fibrosis, together with improved cardiac systolic function and diastolic function. Strikingly, NAC1 treatment, which had the earlier and longer treatment, produced significant improvement of cardiac function and less fibrosis. In the cardiac fibroblasts, NAC blocked cardiac fibroblast proliferation and collagen synthesis induced by hyperglycemia.ConclusionsOur study indicates that NAC treatment in diabetes effectively protects from diabetic cardiomyopathy, possibly through inhibiting the ROS production and fibrosis, which warrants further clarification.Electronic supplementary materialThe online version of this article (doi:10.1186/s12872-015-0076-3) contains supplementary material, which is available to authorized users.

Evidence suggests that various forms of α-synuclein- (αSyn-) mediated microglial activation are associated with the progression of Parkinson’s disease. MicroRNA-155-5p (miR155-5p) is one of the most important microRNAs and enables a robust inflammatory response. Triptolide (T10) is a natural anti-inflammatory component, isolated from a traditional Chinese herb. The objective of the current study was to identify the role and potential regulatory mechanism of T10 in αSyn-induced microglial activation via the miR155-5p mediated SHIP1 signaling pathway. Mouse primary microglia were exposed to monomers, oligomers, and preformed fibrils (PFFs) of human wild-type αSyn, respectively. The expressions of TNFα and IL-1β, measured by enzyme-linked immunosorbent assay (ELISA) and qPCR, demonstrated that PFFs initiated the strongest immunogenicity in microglia. Application of inhibitors of toll-like receptor (TLR) 1/2, TLR4, and TLR9 indicated that PFFs activated microglia mainly via the NF-κB pathway by binding TLR1/2 and TLR4. Treatment with T10 significantly suppressed PFF-induced microglial activation and attenuated the release of proinflammatory cytokines including TNFα and IL-1β. Levels of IRAK1, TRAF6, IKKα/β, p-IKKα/β, NF-κB, p-NF-κB, PI3K, p-PI3K, t-Akt, p-Akt and SHIP1 were measured via Western blot. Levels of miR155-5p were measured by qPCR. The results demonstrated that SHIP1 acted as a downstream target molecule of miR155-5p. Treatment with T10 did not alter the expression of IRAK1 and TRAF6, but significantly decreased the expression of miR155-5p, resulting in upregulation of SHIP1 and repression of NF-κB activity, suggesting inhibition of inflammation and microglial activation. The protective effects of T10 were abolished by the use of SHIP1 siRNA and its inhibitor, 3AC, and miR155-5p mimics. In conclusion, our results demonstrated that treatment with T10 suppressed microglial activation and attenuated the release of proinflammatory cytokines by suppressing NF-κB activity via targeting the miR155-5p/SHIP1 pathway in PFFs-induced microglial activation.

Rapid alterations of gravitational stress during high-performance aircraft push-pull manoeuvres induce dramatic shifts in volume and pressure within the circulation system, which may result in loss of consciousness due to the rapid and significant reduction in cerebral perfusion. There are still no specific and effective countermeasures so far. r We found that lower body negative pressure (LBNP), applied prior to and during −Gz and released at the subsequent transition to +Gz, could effectively counteract gravitational haemodynamic stress induced by a simulated push-pull manoeuvre and improve cerebral diastolic perfusion in human subjects. r We developed a LBNP strategy that effectively protects cerebral perfusion at rapid −Gz to +Gz transitions via improving cerebral blood flow and blood pressure during push-pull manoeuvres and highlight the importance of the timing of the intervention. r Our findings provide a systemic link of integrated responses between the peripheral and cerebral haemodynamic changes during push-pull manoeuvres.

Exosome-mediated nucleic acids delivery has been emerging as a promising strategy for gene therapy. However, the intrinsic offtarget effects due to non-specific uptake of exosomes by other tissues remain the big hurdle for clinical application. In this study, we aimed to enhance the efficacy and minimize the off-target effects by simultaneously encapsulating engineered mRNA translationally activated by tissue-specific microRNA (miRNA) and increasing targeted delivery efficiency via ultrasound-targeted microbubble destruction (UTMD). Briefly, the upstream of interest transcript was engineered to harbor an internal ribosome entry site (IRES) modified with two miRNA recognition sites. In vitro reporter experiments revealed that the engineered mRNA could be encapsulated into exosomes and can be translationally activated by corresponding miRNAs in the recipient cells. By a proof-of-principle in vivo experiment, we encapsulated miR-148a (an adipose relatively specific miRNA)-responsive PGC1a mRNA into exosomes and delivered the exosomes into the adipose tissue with the aid of UTMD. Efficient PGC1a translation was activated in the adipose tissue, together with obvious browning induction. Moreover, there was much lower off-target translation of PGC1 a in lungs and other tissues. Taken together, our study establishes a novel adipose-specific exosome delivery strategy to enhance efficacy and minimize off-target effects simultaneously.