Vesicle formation and trafficking in endothelial cells and regulation of endothelial barrier function

Nanocurcumin prevents memory impairment, hippocampal apoptosis, Akt and CaMKII-α signaling disruption in the central STZ model of Alzheimer's disease in rat

The central route of streptozotocin (STZ) administration has been introduced as a rat model of sporadic Alzheimer's disease (AD). Curcumin was suggested to possess possible neuroprotective effects, which may be profitable in AD. However, the low bioavailability of curcumin hinders its beneficial effects in clinical studies. Earlier studies suggested that a bovine serum albumin-based nanocurcumin, produces superior neuroprotective effects compared to natural curcumin. In the present study, the protective effect of nanocurcumin in rat model of central STZ induced memory impairment was assessed. In addition, due to the importance of the hippocampus in memory, the amounts of hippocampal active caspase-3, Akt, and CaMKII-α were evaluated. Adult male Wistar rats weighing 250-300g were used. STZ (icv) was injected during days 1 and 3 (3mg/kg in divided), and nanocurcumin or curcumin 50mg/kg/oral gavage was administered daily during days 4-14. Morris water maze training was performed on days 15-17, and the retention memory test was achieved on the 18th day. Following memory assessment, the rats were sacrificed and the hippocampi were used to assess caspase-3 cleavage, Akt, and CaMKII-α signaling. The findings revealed that nanocurcumin ingestion (but not natural curcumin) in the dose of 50mg/kg was capable to prevent the impairment of water maze learning and memory induced by central STZ. Molecular assessments indicated that STZ treatment increased the caspase-3 cleavage in the hippocampus while deactivating Akt and CaMKII-α. Nanocurcumin reduced caspase-3 cleavage to a non-significant level compared to control group and restored Akt and CaMKII-α within the hippocampus while natural curcumin exerted no significant effect. These findings might suggest that nanocurcumin can restore memory deficit, hippocampal apoptosis as well as Akt and CaMKII-α signaling disruption associated with brain insulin resistance.

Lipid sulfoxide polymers as potential inhalable drug delivery platforms with differential albumin binding affinity

Inhalable nanomedicines are increasingly being developed to optimise the pharmaceutical treatment of respiratory diseases. Large lipid-based nanosystems at the forefront of the inhalable nanomedicines development pipeline, though, have a number of limitations. The objective of this study was, therefore, to investigate the utility of novel small lipidated sulfoxide polymers based on poly(2-(methylsulfinyl)ethyl acrylate) (PMSEA) as inhalable drug delivery platforms with tuneable membrane permeability imparted by differential albumin binding kinetics. Linear PMSEA (5 kDa) was used as a hydrophilic polymer backbone with excellent anti-fouling and stealth properties compared to poly(ethylene glycol). Terminal lipids comprising single (1C2, 1C12) or double (2C12) chain diglycerides were installed to provide differing affinities for albumin and, by extension, albumin trafficking pathways in the lungs. Albumin binding kinetics, cytotoxicity, lung mucus penetration and cellular uptake and permeability through key cellular barriers in the lungs were examined in vitro. The polymers showed good mucus penetration and no cytotoxicity over 24 h at up to 1 mg ml-1. While 1C2-showed no interaction with albumin, 1C12-PMSEA and 2C12-PMSEA bound albumin with KD values of approximately 76 and 10 μM, respectively. Despite binding to albumin, 2C12-PMSEA showed reduced cell uptake and membrane permeability compared to the smaller polymers and the presence of albumin had little effect on cell uptake and membrane permeability. While PMSEA strongly shielded these lipids from albumin, the data suggest that there is scope to tune the lipid component of these systems to control membrane permeability and cellular interactions in the lungs to tailor drug disposition in the lungs.

Hematopoietic growth factors Regulate Entry of Monocytes into the Adult Brain via Chemokine Receptor CCR5

Monocytes are circulating macrophage precursors and are generated from bone marrow hematopoietic stem cells. In the adults, monocytes continuously replenish cerebral border-associated macrophages under a physiological condition. Monocytes also rapidly infiltrate into the brain in the settings of pathological conditions. The mechanisms of recruiting monocyte-derived macrophages into the brain under pathological conditions have been extensively studied. However, it remains unclear how monocytes enter the brain for renewal of border-associated macrophages under the physiological condition. Using both in vitro and in vivo approaches, this study reveals that the combination of two hematopoietic growth factors, stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF), complementarily and synergistically enhances adhesion of monocytes to cerebral endothelial cells in a dose dependent manner. Cysteine-cysteine chemokine receptor 5 (CCR5) in brain endothelial cells, but not cell adhesion molecules mediating neuroinflammation-related infiltration of monocyte-derived macrophages, modulates the SCF+G-CSF-enhanced monocyte-endothelial cell adhesion. Blocking CCR5 or genetically deleting CCR5 reduces monocyte-endothelial cell adhesion induced by SCF+G-CSF. SCF+G-CSF-enhanced recruitment of bone marrow-derived monocytes/macrophages in cerebral perivascular space is also reduced in adult CCR5 knockout mice. This study demonstrates the contribution of SCF and G-CSF in regulating the entry of monocytes into the adult brain to replenish perivascular macrophages.

Evaluating the clinical efficacy and safety of concurrent chemoradiotherapy with cisplatin and nab-paclitaxel in postoperative early-stage cervical cancer

OBJECTIVE

A preclinical study showed that nab-paclitaxel acted as a radiosensitizer and improved tumor radiotherapy in a supra-additive manner. In this study, we aimed to evaluate the clinical efficacy and safety of concurrent chemoradiotherapy (CCRT) with cisplatin and nab-paclitaxel in postoperative early-stage cervical cancer with an unfavorable prognosis.

METHODS

Eligible patients with stage IB1-IIA2 (FIGO 2009) cervical carcinoma were recruited retrospectively between August 2018 to May 2021. Patients in both the cisplatin and nab-paclitaxel groups received postoperative radiotherapy and weekly intravenous cisplatin 40 mg/m2 or nab-paclitaxel 100 mg concurrently. An analysis of overall survival, progression-free survival, and adverse reactions was conducted.

RESULTS

A total of 105 early-stage cervical cancer patients were included into our study. The median follow-up time was 38.7 months. The 3-year overall survival and progression-free survival in both group was similar. The cycles of chemotherapy in the cisplatin group were less than those in the nab-paclitaxel group (4.5 vs. 5.0; p = 0.001). Patients in the cisplatin group had a significantly higher frequency of hematological adverse events than patients in the nab-paclitaxel group (P < 0.05). Patients in the cisplatin group had a significantly higher frequency of grade 3-4 leukopenia (46.1% vs. 18.9%; P = 0.03), grade 1-2 thrombocytopenia (32.7% vs. 9.5%; P = 0.014) than patients in the nab-paclitaxel group. Gastrointestinal reactions, such as vomiting, nausea, and anorexia were significantly reduced in the nab-paclitaxel group compared with those in the cisplatin group. Regarding the effects on alopecia, the incidence rate of the nab-paclitaxel group was higher than that of the cisplatin group (P = 0.001). There were no differences between the groups in terms of other adverse reactions.

CONCLUSION

The results of this study indicate that nab-paclitaxel-based concurrent radiotherapy is tolerable and effective, and can be considered an alternative to cisplatin chemotherapy.

Shear Stress and Sub-Femtomolar Levels of Ligand Synergize to Activate ALK1 Signaling in Endothelial Cells

Endothelial cells (ECs) respond to concurrent stimulation by biochemical factors and wall shear stress (SS) exerted by blood flow. Disruptions in flow-induced responses can result in remodeling issues and cardiovascular diseases, but the detailed mechanisms linking flow-mechanical cues and biochemical signaling remain unclear. Activin receptor-like kinase 1 (ALK1) integrates SS and ALK1-ligand cues in ECs; ALK1 mutations cause hereditary hemorrhagic telangiectasia (HHT), marked by arteriovenous malformation (AVM) development. However, the mechanistic underpinnings of ALK1 signaling modulation by fluid flow and the link to AVMs remain uncertain. We recorded EC responses under varying SS magnitudes and ALK1 ligand concentrations by assaying pSMAD1/5/9 nuclear localization using a custom multi-SS microfluidic device and a custom image analysis pipeline. We extended the previously reported synergy between SS and BMP9 to include BMP10 and BMP9/10. Moreover, we demonstrated that this synergy is effective even at extremely low SS magnitudes (0.4 dyn/cm2) and ALK1 ligand range (femtogram/mL). The synergistic response to ALK1 ligands and SS requires the kinase activity of ALK1. Moreover, ALK1's basal activity and response to minimal ligand levels depend on endocytosis, distinct from cell-cell junctions, cytoskeleton-mediated mechanosensing, or cholesterol-enriched microdomains. However, an in-depth analysis of ALK1 receptor trafficking's molecular mechanisms requires further investigation.

Symptom-oriented network pharmacology revealed the mechanism of HuangQi-DanShen herb pair against cerebral ischemia coupled with comprehensive chemical characterization

ETHNOPHARMACOLOGICAL RELEVANCE

In the clinical practice of traditional Chinese medicine, HuangQi-DanShen (HD) is an important drug pair for the treatment of cerebral ischemia (CI).

AIM OF THE STUDY

Elucidate the mechanism of HD against CI based on symptom-oriented network pharmacology coupled with comprehensive chemical characterization.

MATERIALS AND METHODS

UHPLC-Q-Exactive Orbitrap-MS technology was firstly used to obtain the chemical profile of HD constituents. A comprehensive strategy combining in-house library, diagnostic ions, Compound Discover software and network databases was then established to identify its chemical constitutes. Symptomatic treatment is a treatment aimed at relieving or eliminating symptoms which is often characterized as a stop-gap measure due to its inability to cure the disease fundamentally. Nevertheless, symptomatic treatment is an indispensable part of clinical practice and has an important place in medical therapeutics. Therefore, network pharmacology technique were used to elucidate molecular mechanisms from the symptoms of CI. Finally, some literatures were further mined to support our conclusions.

RESULTS

A total of 190 ingredients were identified in HD. Symptom-oriented network pharmacology analysis indicated that compounds of HD relieved "blood" through the regulation of ADORA2A, ADORA1, PTPN11, MMP9 and EGFR, relieved "qi" via the regulation of ADORA2A, EGFR, MMP9 and CA2. The therapeutic effect of HD on "faint" was linked to PTPN11 and MMP9, while the regulation of "dyskinesia" was related to ADORA2A and EGFR, and ADORA1, PTPN11 and MMP9 were associated withe its effect on "speech disorder". ADORA1, ADORA2A and MMP9 were key to the HD component in treating "visual disturbance".

CONCLUSION

The approach of symptom-oriented network pharmacology coupled with comprehensive chemical characterization proposed a further orientation for exploring the mechanisms of HD against CI.

Pharmacological functions of salidroside in renal diseases: facts and perspectives

Rhodiola rosea is a valuable functional medicinal plant widely utilized in China and other Asian countries for its anti-fatigue, anti-aging, and altitude sickness prevention properties. Salidroside, a most active constituent derived from Rhodiola rosea, exhibits potent antioxidative, hypoxia-resistant, anti-inflammatory, anticancer, and anti-aging effects that have garnered significant attention. The appreciation of the pharmacological role of salidroside has burgeoned over the last decade, making it a beneficial option for the prevention and treatment of multiple diseases, including atherosclerosis, Alzheimer's disease, Parkinson's disease, cardiovascular disease, and more. With its anti-aging and renoprotective effects, in parallel with the inhibition of oxidative stress and inflammation, salidroside holds promise as a potential therapeutic agent for kidney damage. This article provides an overview of the microinflammatory state in kidney disease and discuss the current therapeutic strategies, with a particular focus on highlighting the recent advancements in utilizing salidroside for renal disease. The potential mechanisms of action of salidroside are primarily associated with the regulation of gene and protein expression in glomerular endothelial cells, podocytes, renal tubule cells, renal mesangial cells and renal cell carcinoma cell, including TNF-α, TGF-β, IL-1β, IL-17A, IL-6, MCP-1, Bcl-2, VEGF, ECM protein, caspase-3, HIF-1α, BIM, as well as the modulation of AMPK/SIRT1, Nrf2/HO-1, Sirt1/PGC-1α, ROS/Src/Cav-1, Akt/GSK-3β, TXNIP-NLRP3, ERK1/2, TGF-β1/Smad2/3, PI3K/Akt, Wnt1/Wnt3a β-catenin, TLR4/NF-κB, MAPK, JAK2/STAT3, SIRT1/Nrf2 pathways. To the best of our knowledge, this review is the first to comprehensively cover the protective effects of salidroside on diverse renal diseases, and suggests that salidroside has great potential to be developed as a drug for the prevention and treatment of metabolic syndrome, cardiovascular and cerebrovascular diseases and renal complications.

Adiposomes from Obese-Diabetic Individuals Promote Endothelial Dysfunction and Loss of Surface Caveolae

Glycosphingolipids (GSLs) are products of lipid glycosylation that have been implicated in the development of cardiovascular diseases. In diabetes, the adipocyte microenvironment is characterized by hyperglycemia and inflammation, resulting in high levels of GSLs. Therefore, we sought to assess the GSL content in extracellular vesicles derived from the adipose tissues (adiposomes) of obese-diabetic (OB-T2D) subjects and their impact on endothelial cell function. To this end, endothelial cells were exposed to adiposomes isolated from OB-T2D versus healthy subjects. Cells were assessed for caveolar integrity and related signaling, such as Src-kinase and caveolin-1 (cav-1) phosphorylation, and functional pathways, such as endothelial nitric oxide synthase (eNOS) activity. Compared with adiposomes from healthy subjects, OB-T2D adiposomes had higher levels of GSLs, especially LacCer and GM3; they promoted cav-1 phosphorylation coupled to an obvious loss of endothelial surface caveolae and induced eNOS-uncoupling, peroxynitrite generation, and cav-1 nitrosylation. These effects were abolished by Src kinase inhibition and were not observed in GSL-depleted adiposomes. At the functional levels, OB-T2D adiposomes reduced nitric oxide production, shear response, and albumin intake in endothelial cells and impaired flow-induced dilation in healthy arterioles. In conclusion, OB-T2D adiposomes carried a detrimental GSL cargo that disturbed endothelial caveolae and the associated signaling.

Endothelial tissue remodeling induced by intraluminal pressure enhances paracellular solute transport

The endothelial layers of the microvasculature regulate the transport of solutes to the surrounding tissues. It remains unclear how this barrier function is affected by blood flow-induced intraluminal pressure. Using a 3D microvessel model, we compare the transport of macromolecules through endothelial tissues at mechanical rest or with intraluminal pressure, and correlate these data with electron microscopy of endothelial junctions. On application of an intraluminal pressure of 100 Pa, we demonstrate that the flow through the tissue increases by 2.35 times. This increase is associated with a 25% expansion of microvessel diameter, which leads to tissue remodeling and thinning of the paracellular junctions. We recapitulate these data with the deformable monopore model, in which the increase in paracellular transport is explained by the augmentation of the diffusion rate across thinned junctions under mechanical stress. We therefore suggest that the deformation of microvasculatures contributes to regulate their barrier function.

Deciphering albumin-directed drug delivery by imaging

Albumin is the most abundant plasma protein, exhibits extended circulating half-life, and its properties have long been exploited for diagnostics and therapies. Many drugs intrinsically bind albumin or have been designed to do so, yet questions remain about true rate limiting factors that govern albumin-based transport and their pharmacological impacts, particularly in advanced solid cancers. Imaging techniques have been central to quantifying - at a molecular and single-cell level - the impact of mechanisms such as phagocytic immune cell signaling, FcRn-mediated recycling, oncogene-driven macropinocytosis, and albumin-drug interactions on spatial albumin deposition and related pharmacology. Macroscopic imaging of albumin-binding probes quantifies vessel structure, permeability, and supports efficiently targeted molecular imaging. Albumin-based imaging in patients and animal disease models thus offers a strategy to understand mechanisms, guide drug development and personalize treatments.

Serum albumin and nucleic acids biodistribution: from molecular aspects to biotechnological applications

Serum albumin (SA) is the most abundant protein in plasma and represents the main carrier of endogenous and exogenous compounds. Several evidence supports the notion that SA binds single and double stranded deoxy- and ribonucleotides at two sites, with values of the dissociation equilibrium constant (i.e., K_d ) ranging from micromolar to nanomolar values. This can be relevant from a physiological and pathological point of view as in human plasma circulate cell-free nucleic acids (cfNAs), which are single and double stranded NAs released by different tissues via apoptosis, necrosis, and secretions. Albeit SA shows low hydrolytic reactivity toward DNA and RNA, the high plasma concentration of this protein and the occurrence of several SA receptors may be pivotal for sequestering and hydrolyzing cfNAs. Therefore, pathological conditions like cancer, characterized by altered levels of human SA or by altered SA post-translational modifications, may influence cfNAs distribution and metabolism. Besides, the stability, solubility, biocompatibility, and low immunogenicity make SA a golden share for biotechnological applications related to the delivery of therapeutic NAs (TNAs). Indeed, pre-clinical studies report the therapeutic potential of SA:TNAs complexes in precision cancer therapy. Here, the molecular and biotechnological implications of SA:NAs interaction are discussed, highlighting new perspectives into SA plasmatic functions. This article is protected by copyright. All rights reserved.

Endothelial Progenitor Cells Dysfunctions and Cardiometabolic Disorders: From Mechanisms to Therapeutic Approaches

Metabolic syndrome (MetS) is a cluster of several disorders, such as hypertension, central obesity, dyslipidemia, hyperglycemia, insulin resistance and non-alcoholic fatty liver disease. Despite health policies based on the promotion of physical exercise, the reduction of calorie intake and the consumption of healthy food, there is still a global rise in the incidence and prevalence of MetS in the world. This phenomenon can partly be explained by the fact that adverse events in the perinatal period can increase the susceptibility to develop cardiometabolic diseases in adulthood. Individuals born after intrauterine growth restriction (IUGR) are particularly at risk of developing cardiovascular diseases (CVD) and metabolic disorders later in life. It has been shown that alterations in the structural and functional integrity of the endothelium can lead to the development of cardiometabolic diseases. The endothelial progenitor cells (EPCs) are circulating components of the endothelium playing a major role in vascular homeostasis. An association has been found between the maintenance of endothelial structure and function by EPCs and their ability to differentiate and repair damaged endothelial tissue. In this narrative review, we explore the alterations of EPCs observed in individuals with cardiometabolic disorders, describe some mechanisms related to such dysfunction and propose some therapeutical approaches to reverse the EPCs dysfunction.

Evaluation of Blood-Brain Barrier Integrity Using Vascular Permeability Markers: Evans Blue, Sodium Fluorescein, Albumin-Alexa Fluor Conjugates, and Horseradish Peroxidase

The blood-brain barrier (BBB) constituted by endothelial cells of brain microvessels is a dynamic interface, which controls and regulates the transport of various substances including peptides, proteins, ions, vitamins, hormones, and immune cells from the circulation into the brain parenchyma. Certain diseases/disorders such as Alzheimer's disease, sepsis, and hypertension can lead to varying degrees of BBB disruption. Moreover, impairment of BBB integrity has been implicated in the pathogenesis of various neurodegenerative diseases like epilepsy. In attempts to explore the wide spectrum of pathophysiologic mechanisms of these diseases/disorders, a variety of experimental insults targeted to the BBB integrity in vitro in cell culture models and in vivo in laboratory animals have been shown to alter BBB permeability causing enhanced transport of certain tracers such as sodium fluorescein, cadaverine-Alexa fluor, horseradish peroxidase, FITC-dextran, albumin-Alexa fluor conjugates, and Evans blue dye across the barrier. The permeability changes in barrier-type endothelial cells can be assessed by intravascular infusion of exogenous tracers and subsequent detection of the extravasated tracer in the brain tissue, which enable functional and structural analysis of BBB integrity. In this chapter, we aimed to highlight the current knowledge on the use of four most commonly performed tracers, namely, Evans blue, sodium fluorescein, albumin-Alexa fluor conjugates, and horseradish peroxidase. The experimental methodologies that we use in our laboratory for the detection of these tracers by macroscopy, spectrophotometry, spectrophotofluorometry, confocal laser scanning microscopy, and electron microscopy are also discussed. Tracing studies at the morphological level are mainly aimed at the identification of the tracers both in the barrier-related cells and brain parenchyma. In addition, BBB permeability to the tracers can be quantified using spectrophotometric and spectrophotofluorometric assays and image analysis by confocal laser scanning microscopy and electron microscopy. The results of our studies conducted under various experimental settings using the mentioned tracers indicate that barrier-type endothelial cells in brain microvessels orchestrate the paracellular and/or transcellular trafficking of substances across BBB. These efforts may not only contribute to designing approaches for the management of diseases/disorders associated with BBB breakdown but may also provide new insights for developing novel brain drug delivery strategies.

Albumin-based nanoparticles as contrast medium for MRI: vascular imaging, tissue and cell interactions, and pharmacokinetics of second-generation nanoparticles

This multidisciplinary study examined the pharmacokinetics of nanoparticles based on albumin-DTPA-gadolinium chelates, testing the hypothesis that these nanoparticles create a stronger vessel signal than conventional gadolinium-based contrast agents and exploring if they are safe for clinical use. Nanoparticles based on human serum albumin, bearing gadolinium and designed for use in magnetic resonance imaging, were used to generate magnet resonance images (MRI) of the vascular system in rats ("blood pool imaging"). At the low nanoparticle doses used for radionuclide imaging, nanoparticle-associated metals were cleared from the blood into the liver during the first 4 h after nanoparticle application. At the higher doses required for MRI, the liver became saturated and kidney and spleen acted as additional sinks for the metals, and accounted for most processing of the nanoparticles. The multiple components of the nanoparticles were cleared independently of one another. Albumin was detected in liver, spleen, and kidneys for up to 2 days after intravenous injection. Gadolinium was retained in the liver, kidneys, and spleen in significant concentrations for much longer. Gadolinium was present as significant fractions of initial dose for longer than 2 weeks after application, and gadolinium clearance was only complete after 6 weeks. Our analysis could not account quantitatively for the full dose of gadolinium that was applied, but numerous organs were found to contain gadolinium in the collagen of their connective tissues. Multiple lines of evidence indicated intracellular processing opening the DTPA chelates and leading to gadolinium long-term storage, in particular inside lysosomes. Turnover of the stored gadolinium was found to occur in soluble form in the kidneys, the liver, and the colon for up to 3 weeks after application. Gadolinium overload poses a significant hazard due to the high toxicity of free gadolinium ions. We discuss the relevance of our findings to gadolinium-deposition diseases.

Circulating GFAP and Iba-1 levels are associated with pathophysiological sequelae in the thalamus in a pig model of mild TBI

Serum biomarkers are promising tools for evaluating patients following traumatic brain injury (TBI). However, their relationship with diffuse histopathology remains unclear. Additionally, translatability is a focus of neurotrauma research, however, studies using translational animal models are limited. Here, we evaluated associations between circulating biomarkers and acute thalamic histopathology in a translational micro pig model of mTBI. Serum samples were collected pre-injury, and 1 min-6 h following mTBI. Markers of neuronal injury (Ubiquitin Carboxy-terminal Hydrolase L1 [UCH-L1]), microglial/macrophage activation (Ionized calcium binding adaptor molecule-1 [Iba-1]) and interleukin-6 [IL-6]) and astrogliosis/astrocyte damage (glial fibrillary acidic protein [GFAP]) were measured. Axonal injury and histological features of neurons and glia were also investigated using immunofluorescent labeling and correlated to serum levels of the associated biomarkers. Consistent with prior experimental and human studies, GFAP, was highest at 6 h post-injury, while no substantial changes were observed in UCH-L1, Iba-1 or IL-6 over 6 h. This study also found promising associations between thalamic glial histological signatures and ensuing release of Iba-1 and GFAP into the circulation. Our findings suggest that in diffuse injury, monitoring serum Iba-1 and GFAP levels can provide clinically relevant insight into the underlying acute pathophysiology and biomarker release kinetics following mTBI, providing previously underappreciated diagnostic capability.

Targeting drug delivery in the vascular system: Focus on endothelium

The bloodstream is the main transporting pathway for drug delivery systems (DDS) from the site of administration to the intended site of action. In many cases, components of the vascular system represent therapeutic targets. Endothelial cells, which line the luminal surface of the vasculature, play a tripartite role of the key target, barrier, or victim of nanomedicines in the bloodstream. Circulating DDS may accumulate in the vascular areas of interest and in off-target areas via mechanisms bypassing specific molecular recognition, but using ligands of specific vascular determinant molecules enables a degree of precision, efficacy, and specificity of delivery unattainable by non-affinity DDS. Three decades of research efforts have focused on specific vascular targeting, which have yielded a multitude of DDS, many of which are currently undergoing a translational phase of development for biomedical applications, including interventions in the cardiovascular, pulmonary, and central nervous systems, regulation of endothelial functions, host defense, and permeation of vascular barriers. We discuss the design of endothelial-targeted nanocarriers, factors underlying their interactions with cells and tissues, and describe examples of their investigational use in models of acute vascular inflammation with an eye on translational challenges.

Lung Endothelial Transcytosis

Transcytosis of macromolecules through lung endothelial cells is the primary route of transport from the vascular compartment into the interstitial space. Endothelial transcytosis is mostly a caveolae-dependent process that combines receptor-mediated endocytosis, vesicle trafficking via actin-cytoskeletal remodeling, and SNARE protein directed vesicle fusion and exocytosis. Herein, we review the current literature on caveolae-mediated endocytosis, the role of actin cytoskeleton in caveolae stabilization at the plasma membrane, actin remodeling during vesicle trafficking, and exocytosis of caveolar vesicles. Next, we provide a concise summary of experimental methods employed to assess transcytosis. Finally, we review evidence that transcytosis contributes to the pathogenesis of acute lung injury. © 2020 American Physiological Society. Compr Physiol 10:491-508, 2020.

Photodynamic therapy mediated by aluminium-phthalocyanine nanoemulsion eliminates primary tumors and pulmonary metastases in a murine 4T1 breast adenocarcinoma model

Photodynamic therapy (PDT) is effective in the treatment of different types of cancer, such as basal cell carcinoma and other superficial cancers. However, improvements in photosensitizer delivery are still needed, and the use of PDT against more deeply located tumors has been the subject of many studies. Thus, the goal of this study was to evaluate the efficacy of a nanoemulsion containing aluminium-phthalocyanine (AlPc-NE) as a mediator of photodynamic therapy (PDT-AlPc-NE) against grafted 4T1 breast adenocarcinoma tumors in mice (BALB/c). Short after the appearance of the tumor, the animals were divided into groups (n = 5) as follows: untreated; only AlPc-NE and treated with PDT-AlPc-NE. The tumor volume was measured with a digital calliper at specific times. The presence of metastasis in the lungs was evaluated by microtomography and histopathological analyses. The results show that the application of PDT-AlPc-NE eradicated the transplanted tumors in all the treated animals, while the animals from control groups presented a robust increase in the tumor volume. Still more significantly, microtomography showed the animals submitted the PDT-AlPc-NE to be free of detectable metastasis in the lungs. The histological analysis of the lungs further confirmed the results verified by the microtomography. Therefore, this study suggests that PDT-AlPc-NE is effective in the elimination of experimentally grafted breast tumors in mice and also in preventing the formation of metastasis in the lungs.

3D rotational motion of an endocytic vesicle on a complex microtubule network in a living cell

The transport dynamics of endocytic vesicles in a living cell contains essential biomedical information. Although the movement mechanism of a vesicle by motor proteins has been revealed, understanding the precise movement of vesicles on the cytoskeleton in a living cell has been considered challenging, due to the complex 3D network of cytoskeletons. Here, we specify the shape of the 3D interaction between the vesicle and microtubule, based on the theoretically estimated location of the microtubule and the vesicle trajectory data acquired at high spatial and temporal precision. We detected that vesicles showed more frequent direction changes with either in very acute or in obtuse angles than right angles, on similar time scales in a microtubule network. Interestingly, when a vesicle interacted with a relatively longer (> 400 nm) microtubule filament, rotational movement along the axis of the microtubule was frequently observed. Our results are expected to give in-depth insight into understanding the actual 3D interactions between the intracellular molecule and complex cytoskeletal network.

Apolipoprotein M-bound sphingosine-1-phosphate regulates blood-brain barrier paracellular permeability and transcytosis

The blood-brain barrier (BBB) is formed by the endothelial cells lining cerebral microvessels, but how blood-borne signaling molecules influence permeability is incompletely understood. We here examined how the apolipoprotein M (apoM)-bound sphingosine 1-phosphate (S1P) signaling pathway affects the BBB in different categories of cerebral microvessels using ApoM deficient mice (Apom-/-). We used two-photon microscopy to monitor BBB permeability of sodium fluorescein (376 Da), Alexa Fluor (643 Da), and fluorescent albumin (45 kDA). We show that BBB permeability to small molecules increases in Apom-/- mice. Vesicle-mediated transfer of albumin in arterioles increased 3 to 10-fold in Apom-/- mice, whereas transcytosis in capillaries and venules remained unchanged. The S1P receptor 1 agonist SEW2871 rapidly normalized paracellular BBB permeability in Apom-/- mice, and inhibited transcytosis in penetrating arterioles, but not in pial arterioles. Thus, apoM-bound S1P maintains low paracellular BBB permeability in all cerebral microvessels and low levels of vesicle-mediated transport in penetrating arterioles.

Altered expression of caveolin-1 in the colon of patients with Hirschsprung's disease

BACKGROUND/PURPOSE

The pathogenesis of Hirschsprung's disease-associated enterocolitis (HAEC) is unclear. Caveolin-1 (Cav-1) regulates the functions of different nitric oxide synthase (NOS) isoforms, which play critical roles in inflammation and intestinal epithelial barrier function. We designed this study to investigate the hypothesis that Cav-1 expression is altered in the bowel of patients with Hirschsprung's disease (HSCR).

METHODS

HSCR tissue specimens (n = 10) were collected at the time of pull-through surgery and control samples were obtained at the time of colostomy closure in patients with imperforate anus (n = 10). qRT-PCR analysis was undertaken to quantify Cav-1 gene expression, and Western blot analysis was undertaken to determine Cav-1 protein quantification. Immunolabelling of Cav-1 proteins was visualized using confocal microscopy.

RESULTS

qRT-PCR and Western blot analysis revealed that Cav-1 was significantly downregulated in the aganglionic and ganglionic colon of patients with HSCR compared to controls (p < 0.01). Confocal microscopy revealed a markedly decreased expression of Cav-1 in colonic epithelium of aganglionic and ganglionic bowel of patients with HSCR compared to controls.

CONCLUSION

To our knowledge, this is the first report of significantly decreased Cav-1 expression in patients with HSCR. Decreased expression of Cav-1 in the bowel of HSCR may increase susceptibility to HAEC in HSCR.

Curcumin-Loaded BSA Nanoparticles Protect More Efficiently Than Natural Curcumin Against Scopolamine-Induced Memory Retrieval Deficit

Introduction:

There is evidence indicating that the rate of AD is lower in curry consuming populations. Then, there is an effort to elucidate if curcumin -as the main ingredient of turmeric-might affect the process of AD. However, in clinical trials of AD, a six-month curcumin treatment failed to show any progress, which might be attributable to its low bioavailability. In this line, a recent human study revealed that a more bioavailable solid lipid curcumin enhances cognition in aged adults. By the application of Bovine Serum Albumin (BSA), the current study aimed at converting curcumin to nano sizes and assessing its protective effects against scopolamine-induced passive avoidance memory retrieval deficit.

Methods:

Nanocurcumin was prepared via dissolution method. Male NMRI mice (20–25 g body weight) were used. The effective doses of nanocurcumin were selected according to the initial pilot test. The mice were treated with nanocurcumin 15 or 20 mg/kg/p.o or distilled water for 10 days. The animals were habituated and trained in passive avoidance apparatus on the day 10. The retention test was performed 24 hours later. Scopolamine (1 mg/kg/i.p.) or saline was injected 30 minutes before memory retention trial.

Results:

The findings indicated that nanocurcumin in doses 15 or 20 mg/kg/p.o prevented the retrieval deficit induced by scopolamine while natural curcumin in its equivalent doses did not have such an effect. Furthermore, nanocurcumin by itself improved memory retention comparing with the control group.

Conclusion:

These findings implied that the potential anti-amnesic effects of curcumin might be observed by producing and using its nanoformulation form.

Acute pain alters P-glycoprotein-containing protein complexes in rat cerebral microvessels: Implications for P-glycoprotein trafficking

P-glycoprotein (PgP) is the major drug efflux pump in human cerebral microvessels. PgP prevents pathogens, toxins and therapeutic drugs from entering the CNS. Understanding the molecular regulation of PgP activity will suggest novel mechanisms to improve CNS drug delivery. Previously, we found that during peripheral inflammatory pain (PIP) (3 h after λ carrageenan injection in the rat paw), PgP traffics to the cortical microvessel endothelial cell plasma membrane concomitant with increased PgP activity. In the current study, we measured the changes in composition of PgP-containing protein complexes after PIP in rat microvessel isolates. We found that a portion of the PgP is contained in a multi-protein complex that also contains the caveolar proteins CAV1, SDPR, PTRF and PRKCDBP. With PIP, total CAV1 bound to PgP was unchanged; however, phosphorylated CAV1 (Y14P-CAV1) in the complex increased. There were few PgP/CAV1 complexes relative to total PgP and CAV1 in the microvessels suggesting CAV1 bound to PgP is unlikely to affect total PgP activity. However, both PgP and CAV1 trafficked away from the nucleus in response to PIP. These data suggest that P-CAV1 bound to PgP potentially regulates PgP trafficking and contributes to the acute PgP activity increase after a PIP stimulus.

Roles of fibronectin isoforms in neonatal vascular development and matrix integrity

Fibronectin (FN) exists in two forms—plasma FN (pFN) and cellular FN (cFN). Although the role of FN in embryonic blood vessel development is well established, its function and the contribution of individual isoforms in early postnatal vascular development are poorly understood. Here, we employed a tamoxifen-dependent cFN inducible knockout (cFN iKO) mouse model to study the consequences of postnatal cFN deletion in smooth muscle cells (SMCs), the major cell type in the vascular wall. Deletion of cFN influences collagen deposition but does not affect life span. Unexpectedly, pFN translocated to the aortic wall in the cFN iKO and in control mice, possibly rescuing the loss of cFN. Postnatal pFN deletion did not show a histological aortic phenotype. Double knockout (dKO) mice lacking both, cFN in SMCs and pFN, resulted in postnatal lethality. These data demonstrate a safeguard role of pFN in vascular stability and the dispensability of the individual FN isoforms in postnatal vascular development. Complete absence of FNs in the dKOs resulted in a disorganized tunica media of the aortic wall. Matrix analysis revealed common and differential roles of the FN isoforms in guiding the assembly/deposition of elastogenic extracellular matrix (ECM) proteins in the aortic wall. In addition, we determined with two cell culture models that that the two FN isoforms acted similarly in supporting matrix formation with a greater contribution from cFN. Together, these data show that pFN exerts a critical role in safeguarding vascular organization and health, and that the two FN isoforms function in an overlapping as well as distinct manner to maintain postnatal vascular matrix integrity.

Fibronectin is a protein that exists in vertebrates in two distinct forms: one present in the blood and the other in blood vessel walls. In mammals, fibronectin is important for the development of blood vessels before birth, but whether it is continuously required for blood vessel homeostasis from birth to adulthood is unknown. We present important results from three genetically modified mouse models, which show that at least one form of fibronectin is required for the proper function and integrity of blood vessels during this period. We show that fibronectin can be transferred from the blood into the vessel wall, where it can rescue the integrity of blood vessels in the absence of the vessel form. This represents an important biological mechanism to maintain the health of blood vessels. Our data also highlight the importance of both fibronectin forms in producing and organizing the microenvironment of cells, with a higher contribution from the fibronectin form residing in the blood vessel walls. Together, our findings show that fibronectin from the blood acts as a safeguard to maintain the health of blood vessels, and both fibronectin forms play crucial roles in development and support of the blood vessel microenvironment.

Arginase upregulation and eNOS uncoupling contribute to impaired endothelium-dependent vasodilation in a rat model of intrauterine growth restriction

Individuals born after intrauterine growth restriction (IUGR) are at increased risk of developing cardiovascular diseases in adulthood, notably hypertension (HTN). Alterations in the vascular system, particularly impaired endothelium-dependent vasodilation, may play an important role in long-term effects of IUGR. Whether such vascular dysfunction precedes HTN has not been fully established in individuals born after IUGR. Moreover, the intimate mechanisms of altered endothelium-dependent vasodilation remain incompletely elucidated. We therefore investigated, using a rat model of IUGR, whether impaired endothelium-dependent relaxation precedes the development of HTN and whether key components of the l-arginine-nitric oxide (NO) pathway are involved in its pathogenesis. Pregnant rats were fed with a control (CTRL, 23% casein) or low-protein diet (LPD, 9% casein) to induce IUGR. Systolic blood pressure (SBP) was measured by tail-cuff plethysmography in 5- and 8-wk-old male offspring. Aortic rings were isolated to investigate relaxation to acetylcholine, NO production, endothelial NO synthase (eNOS) protein content, arginase activity, and superoxide anion production. SBP was not different at 5 wk but significantly increased in 8-wk-old offspring of maternal LPD (LP) versus CTRL offspring. In 5-wk-old LP versus CTRL males, endothelium-dependent vasorelaxation was significantly impaired but restored by preincubation with l-arginine or the arginase inhibitor S-(2-boronoethyl)-l-cysteine; NO production was significantly reduced but restored by l-arginine pretreatment; total eNOS protein, dimer-to-monomer ratio, and arginase activity were significantly increased; superoxide anion production was significantly enhanced but normalized by pretreatment with the NO synthase inhibitor N^ω-nitro-l-arginine. In this model, IUGR leads to early-impaired endothelium-dependent vasorelaxation, resulting from arginase upregulation and eNOS uncoupling, which precedes the development of HTN.

Transcytosis Involvement in Transport System and Endothelial Permeability of Vascular Leakage during Dengue Virus Infection

The major role of endothelial cells is to maintain homeostasis of vascular permeability and to preserve the integrity of vascular vessels to prevent fluid leakage. Properly functioning endothelial cells promote physiological balance and stability for blood circulation and fluid components. A monolayer of endothelial cells has the ability to regulate paracellular and transcellular pathways for transport proteins, solutes, and fluid. In addition to the paracellular pathway, the transcellular pathway is another route of endothelial permeability that mediates vascular permeability under physiologic conditions. The transcellular pathway was found to be associated with an assortment of disease pathogeneses. The clinical manifestation of severe dengue infection in humans is vascular leakage and hemorrhagic diatheses. This review explores and describes the transcellular pathway, which is an alternate route of vascular permeability during dengue infection that corresponds with the pathologic finding of intact tight junction. This pathway may be the route of albumin transport that causes endothelial dysfunction during dengue virus infection.

Biomacromolecules as carriers in drug delivery and tissue engineering

Natural biomacromolecules have attracted increased attention as carriers in biomedicine in recent years because of their inherent biochemical and biophysical properties including renewability, nontoxicity, biocompatibility, biodegradability, long blood circulation time and targeting ability. Recent advances in our understanding of the biological functions of natural-origin biomacromolecules and the progress in the study of biological drug carriers indicate that such carriers may have advantages over synthetic material-based carriers in terms of half-life, stability, safety and ease of manufacture. In this review, we give a brief introduction to the biochemical properties of the widely used biomacromolecule-based carriers such as albumin, lipoproteins and polysaccharides. Then examples from the clinic and in recent laboratory development are summarized. Finally the current challenges and future prospects of present biological carriers are discussed.

Role of the Protein Corona Derived from Human Plasma in Cellular Interactions between Nanoporous Human Serum Albumin Particles and Endothelial Cells

The presence of a protein corona on various synthetic nanomaterials has been shown to strongly influence how they interact with cells. However, it is unclear if the protein corona also exists on protein particles, and if so, its role in particle-cell interactions. In this study, pure human serum albumin (HSA) particles were fabricated via mesoporous silica particle templating. Our data reveal that various serum proteins adsorbed on the particles, when exposed to human blood plasma, forming a corona. In human umbilical vein endothelial cells (HUVECs), the corona was shown to decrease particle binding to the cell membrane, increase the residence time of particles in early endosomes, and reduce the amount of internalized particles within the first hours of exposure to particles. These findings reveal important information regarding the mechanisms used by vascular endothelial cells to internalize protein-based particulate materials exposed to blood plasma. The ability to control the cellular recognition of these organic particles is expected to aid the advancement of HSA-based materials for intravenous drug delivery.

Endothelial dysfunction in individuals born after fetal growth restriction: cardiovascular and renal consequences and preventive approaches

Individuals born after intrauterine growth restriction (IUGR) have an increased risk of perinatal morbidity/mortality, and those who survive face long-term consequences such as cardiovascular-related diseases, including systemic hypertension, atherosclerosis, coronary heart disease and chronic kidney disease. In addition to the demonstrated long-term effects of decreased nephron endowment and hyperactivity of the hypothalamic-pituitary-adrenal axis, individuals born after IUGR also exhibit early alterations in vascular structure and function, which have been identified as key factors of the development of cardiovascular-related diseases. The endothelium plays a major role in maintaining vascular function and homeostasis. Therefore, it is not surprising that impaired endothelial function can lead to the long-term development of vascular-related diseases. Endothelial dysfunction, particularly impaired endothelium-dependent vasodilation and vascular remodeling, involves decreased nitric oxide (NO) bioavailability, impaired endothelial NO synthase functionality, increased oxidative stress, endothelial progenitor cells dysfunction and accelerated vascular senescence. Preventive approaches such as breastfeeding, supplementation with folate, vitamins, antioxidants, L-citrulline, L-arginine and treatment with NO modulators represent promising strategies for improving endothelial function, mitigating long-term outcomes and possibly preventing IUGR of vascular origin. Moreover, the identification of early biomarkers of endothelial dysfunction, especially epigenetic biomarkers, could allow early screening and follow-up of individuals at risk of developing cardiovascular and renal diseases, thus contributing to the development of preventive and therapeutic strategies to avert the long-term effects of endothelial dysfunction in infants born after IUGR.

Intravenously Transplanted Human Bone Marrow Endothelial Progenitor Cells Engraft Within Brain Capillaries, Preserve Mitochondrial Morphology, and Display Pinocytotic Activity Toward Blood-Brain Barrier Repair in Ischemic Stroke Rats

Stroke is a life-threatening disease with limited therapeutic options. Cell therapy has emerged as an experimental stroke treatment. Blood-brain barrier (BBB) impairment is a key pathological manifestation of ischemic stroke, and barrier repair is an innovative target for neurorestoration in stroke. Here, we evaluated via electron microscopy the ability of transplanted human bone marrow endothelial progenitor cells (hBMEPCs) to repair the BBB in adult Sprague-Dawley rats subjected to transient middle cerebral artery occlusion (tMCAO). β-galactosidase prelabeled hBMEPCs were intravenously transplanted 48 hours post-tMCAO. Ultrastructural analysis of microvessels in nontransplant stroke rats revealed typical BBB pathology. At 5 days post-transplantation with hBMEPCs, stroke rats displayed widespread vascular repair in bilateral striatum and motor cortex, characterized by robust cell engraftment within capillaries. hBMEPC transplanted stroke rats exhibited near normal morphology of endothelial cells (ECs), pericytes, and astrocytes, without detectable perivascular edema. Near normal morphology of mitochondria was also detected in ECs and perivascular astrocytes from transplanted stroke rats. Equally notable, we observed numerous pinocytic vesicles within engrafted cells. Robust engraftment and intricate functionality of transplanted hBMEPCs likely abrogated stroke-altered vasculature. Preserving mitochondria and augmenting pinocytosis in cell-based therapeutics represent a new neurorestorative mechanism in BBB repair for stroke. Stem Cells 2017;35:1246-1258.

Modulation of long-term endothelial-barrier integrity is conditional to the cross-talk between Akt and Src signaling

Although numerous studies have implicated Akt and Src kinases in vascular endothelial growth factor (VEGF) and Angiopoietin-1 (Ang-1)-induced endothelial-barrier regulation, a link between these two pathways has never been demonstrated. We determined the long-term effects of Akt inhibition on Src activity and vice versa, and in turn, on the human microvascular endothelial cell (HMEC) barrier integrity at the basal level, and in response to growth factors. Our data showed that Akt1 gene knockdown increases gap formation in HMEC monolayer at the basal level. Pharmacological inhibition of Akt, but not Src resulted in exacerbated VEGF-induced vascular leakage and impaired Ang-1-induced HMEC-barrier protection in vitro at 24 hr. Whereas inhibition of Akt had no effect on VEGF-induced HMEC gap formation in the short term, inhibition of Src blunted this process. In contrast, inhibition of Akt disrupted the VEGF and Ang-1 stabilized barrier integrity in the long-term while inhibition of Src did not. Interestingly, both long-term Akt inhibition and Akt1 gene knockdown in HMECs resulted in increased Tyr416 phosphorylation of Src. Treatment of HMECs with transforming growth factor-β1 (TGFβ1) that inhibited Akt Ser473 phosphorylation in the long-term, activated Src through increased Tyr416 phosphorylation and decreased HMEC-barrier resistance. The effect of TGFβ1 on endothelial-barrier breakdown was blunted in Akt1 deficient HMEC monolayers, where endothelial-barrier resistance was already impaired compared to the control. To our knowledge, this is the first report demonstrating a direct cross-talk between Akt and Src in endothelial-barrier regulation.

Complete response to azacitidine priming and nab-paclitaxel in non-Hodgkin lymphoma resistant to biochemotherapy

The standard of care for first-line therapy in diffuse large B-cell lymphoma (DLBCL) is the rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) regimen. For patients who fail to respond, have an incomplete response or relapse, numerous effective options exists besides salvage cisplatin-based regimen and autologous stem cell therapy. Even with this approach, the outcome remains very poor for this group of patients. The present case illustrates a 55-year-old woman diagnosed with DLBCL, who experienced an early incomplete response, later progression during treatment with the R-CHOP regimen. The patient received salvage therapy with rituximab, cisplatin and gemcitabine, again with an incomplete response. The patient declined consideration for stem cell therapy. Her disease progressed and she enrolled in the present phase I trial using azacitadine priming and nanoalbumin-bound (nab)-paclitaxel. After three cycles, follow-up positron emission tomography/computed tomography revealed a complete response for the first time since her initial diagnosis and the patient has remained disease-free for >6 years. Azacitadine and nab-paclitaxel combination appeared to be an effective regimen for the treatment of this patient with refractory DLBCL.

A phase 2 study of nanoparticle albumin-bound paclitaxel plus nedaplatin for patients with advanced, recurrent, or metastatic cervical carcinoma

BACKGROUND

Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) and nedaplatin (NDP) are used for the treatment of patients with cervical cancer. However, to the authors' knowledge, the use of this combination regimen among patients with advanced, recurrent, or metastatic cervical cancer has rarely been reported.

METHODS

Patients with pathologically confirmed, stage IVB (FIGO staging 2009), recurrent or metastatic cervical cancer were eligible. Nab-paclitaxel at a dose of 175 mg/m² plus NDP at a dose of 80 mg/m² was administered intravenously every 3 weeks. The primary endpoint of the current study was the objective response rate (ORR). The secondary endpoints were progression-free survival, overall survival, and safety.

RESULTS

A total of 27 patients were included (5 with late-stage and 22 with recurrent or metastatic disease). The mean age of the patients was 48.26 ± 9.21 years. Of these 27 patients, 25 had squamous cell carcinoma (92.6%). A total of 26 patients completed 92 cycles of chemotherapy, with an average of 3.4 cycles per patient. The ORR was 50.0% (13 of 26 patients). The overall survival was 16.6 months (95% confidence interval, 12.6-20.6 months) and the progression-free survival was 9.1 months (95% confidence interval, 2.4-15.8 months).The ORR of patients with an interval of >12 months from receipt of prior chemotherapy was significantly higher than that of those with a shorter interval (71.4% vs 25.0%; P = .034). The most common adverse effects reported were myelosuppression, gastrointestinal reactions, fatigue, and peripheral neuropathy. The incidence of grade 3 neutropenia was 33.3% (adverse effects were graded on a scale from 0 to 4 according to the National Cancer Institute's Common Terminology Criteria for Adverse Events [version 3.0]). The incidence of grade 3 thrombocytopenia and anemia was 7.4% and 18.5%, respectively. The incidence of grade 1 to 2 peripheral neuropathy was reported to be as high as 51.9%. No case of hypersensitivity was observed.

CONCLUSIONS

The combination of nab-paclitaxel plus NDP for the treatment of patients with late-stage, recurrent, or metastatic cervical cancer appears to be active and tolerable. Cancer 2017;123:420-425. © 2016 American Cancer Society.

A novel mechanism of action for salidroside to alleviate diabetic albuminuria: effects on albumin transcytosis across glomerular endothelial cells

Salidroside (SAL) is a phenylethanoid glycoside isolated from the medicinal plant Rhodiola rosea. R. rosea has been reported to have beneficial effects on diabetic nephropathy (DN) and high-glucose (HG)-induced mesangial cell proliferation. Given the importance of caveolin-1 (Cav-1) in transcytosis of albumin across the endothelial barrier, the present study was designed to elucidate whether SAL could inhibit Cav-1 phosphorylation and reduce the albumin transcytosis across glomerular endothelial cells (GECs) to alleviate diabetic albuminuria as well as to explore its upstream signaling pathway. To assess the therapeutic potential of SAL and the mechanisms involved in DN albuminuria, we orally administered SAL to db/db mice, and the effect of SAL on the albuminuria was measured. The albumin transcytosis across GECs was explored in a newly established in vitro cellular model. The ratio of albumin to creatinine was significantly reduced upon SAL treatment in db/db mice. SAL decreased the albumin transcytosis across GECs in both normoglycemic and hyperglycemic conditions. SAL reversed the HG-induced downregulation of AMP-activated protein kinase and upregulation of Src kinase and blocked the upregulation Cav-1 phosphorylation. Meanwhile, SAL decreased mitochondrial superoxide anion production and moderately depolarized mitochondrial membrane potential. We conclude that SAL exerts its proteinuria-alleviating effects by downregulation of Cav-1 phosphorylation and inhibition of albumin transcytosis across GECs. These studies provide the first evidence of interference with albumin transcytosis across GECs as a novel approach to the treatment of diabetic albuminuria.

Cardiopulmonary bypass increases pulmonary microvascular permeability through the Src kinase pathway: Involvement of caveolin-1 and vascular endothelial cadherin

Changes in pulmonary microvascular permeability following cardiopulmonary bypass (CPB) and the underlying mechanisms have not yet been established. Therefore, the aim of the present study was to elucidate the alterations in pulmonary microvascular permeability following CPB and the underlying mechanism. The pulmonary microvascular permeability was measured using Evans Blue dye (EBD) exclusion, and the neutrophil infiltration and proinflammatory cytokine secretion was investigated. In addition, the activation of Src kinase and the phosphorylation of caveolin-1 and vascular endothelial cadherin (VE-cadherin) was examined. The results revealed that CPB increased pulmonary microvascular leakage, neutrophil count and proinflammatory cytokines in the bronchoalveolar lavage fluid, and activated Src kinase. The administration of PP2, an inhibitor of Src kinase, decreased the activation of Src kinase and attenuated the increase in pulmonary microvascular permeability observed following CPB. Two important proteins associated with vascular permeability, caveolin-1 and VE-cadherin, were significantly activated at 24 h in the lung tissues following CPB, which correlated with the alterations in pulmonary microvascular permeability and Src kinase. PP2 administration inhibited their activation, suggesting that they are downstream factors of Src kinase activation. The data indicated that the Src kinase pathway increased pulmonary microvascular permeability following CPB, and the activation of caveolin-1 and VE-cadherin may be involved. Inhibition of this pathway may provide a potential therapy for acute lung injury following cardiac surgery.

Effects of beta-hydroxybutyrate on brain vascular permeability in rats with traumatic brain injury

This study investigates the effect of beta-hydroxybutyrate (BHB) on blood-brain barrier (BBB) integrity during traumatic brain injury (TBI) in rats. Evans blue (EB) and horseradish peroxidase (HRP) were used as determinants of BBB permeability. Glutathione (GSH) and malondialdehyde (MDA) levels were estimated in the right (injury side) cerebral cortex of animals. The gene expression levels for occludin, glucose transporter (Glut)-1, aquaporin4 (AQP4) and nuclear factor-kappaB (NF-κB) were performed, and Glut-1 and NF-κB activities were analyzed. BHB treatment decreased GSH and MDA levels in intact animals and in those exposed to TBI (P<0.05). Glut-1 protein levels decreased in sham, BHB and TBI plus BHB groups (P<0.05). NF-κB protein levels increased in animals treated with BHB and/or exposed to TBI (P<0.05). The expression levels of occludin and AQP4 did not significantly change among experimental groups. Glut-1 expression levels increased in BHB treated and untreated animals exposed to TBI (P<0.05). While NF-κB expression levels increased in animals in TBI (P<0.01), a decrease was noticed in these animals upon BHB treatment (P<0.01). In animals exposed to TBI, EB extravasation was observed in the ipsilateral cortex regardless of BHB treatment. Ultrastructurally, BHB attenuated but did not prevent the presence of HRP in brain capillary endothelial cells of animals with TBI; moreover, the drug also led to the observation of the tracer when used in intact rats (P<0.01). Altogether, these results showed that BHB not only failed to provide overall protective effects on BBB in TBI but also led to BBB disruption in healthy animals.

Targeted endothelial nanomedicine for common acute pathological conditions

Endothelium, a thin monolayer of specialized cells lining the lumen of blood vessels is the key regulatory interface between blood and tissues. Endothelial abnormalities are implicated in many diseases, including common acute conditions with high morbidity and mortality lacking therapy, in part because drugs and drug carriers have no natural endothelial affinity. Precise endothelial drug delivery may improve management of these conditions. Using ligands of molecules exposed to the bloodstream on the endothelial surface enables design of diverse targeted endothelial nanomedicine agents. Target molecules and binding epitopes must be accessible to drug carriers, carriers must be free of harmful effects, and targeting should provide desirable sub-cellular addressing of the drug cargo. The roster of current candidate target molecules for endothelial nanomedicine includes peptidases and other enzymes, cell adhesion molecules and integrins, localized in different domains of the endothelial plasmalemma and differentially distributed throughout the vasculature. Endowing carriers with an affinity to specific endothelial epitopes enables an unprecedented level of precision of control of drug delivery: binding to selected endothelial cell phenotypes, cellular addressing and duration of therapeutic effects. Features of nanocarrier design such as choice of epitope and ligand control delivery and effect of targeted endothelial nanomedicine agents. Pathological factors modulate endothelial targeting and uptake of nanocarriers. Selection of optimal binding sites and design features of nanocarriers are key controllable factors that can be iteratively engineered based on their performance from in vitro to pre-clinical in vivo experimental models. Targeted endothelial nanomedicine agents provide antioxidant, anti-inflammatory and other therapeutic effects unattainable by non-targeted counterparts in animal models of common acute severe human disease conditions. The results of animal studies provide the basis for the challenging translation endothelial nanomedicine into the clinical domain.

Abrogated cardioprotective effect of ischemic preconditioning in ovariectomized rat heart

BACKGROUND

Ischemic heart disease is the leading cause of death in postmenopausal women. The expression of caveolin, a membrane protein and a negative regulator of nitric oxide (NO), increases after menopause. The present study was designed to determine the effect of daidzein (DDZ), a phytoestrogen in attenuated cardioprotective effect of ischemic preconditioning (IPC) in ovariectomized rat heart.

METHODS

Heart was isolated from ovariectomized rat and mounted on Langendorff's apparatus, subjected to 30 min ischemia and 120 min reperfusion. IPC was mediated by four cycles of 5 min ischemia and 5 min reperfusion. The infarct size was estimated using triphenyltetrazolium chloride stain, and coronary effluent was analyzed for lactate dehydrogenase and creatine kinase MB (CK-MB) release to assess the degree of myocardial injury. The release of NO was estimated indirectly by measuring the release of nitrite in coronary effluent.

RESULTS

IPC-induced cardioprotection was significantly attenuated in ovariectomized rats as compared to normal rats, which was restored by treatment of DDZ, a caveolin inhibitor (0.2 mg/kg subcutaneously) for 1 week. However, this observed cardioprotection was significantly attenuated by perfusion of l-nitroarginine methyl ester, an endothelial nitric oxide synthase (eNOS) inhibitor (100 µM/L) and glibenclamide, an adenosine triphosphate-sensitive potassium ion channel blocker (10 µM/L) alone or in combination, noted in terms of increase in myocardial infarct size, release of LDH and CK-MB, and also decrease in the release of NO.

CONCLUSION

Thus, it is suggested that DDZ restores the attenuated cardioprotective effect in ovariectomized rat heart, which may be due to downregulation of caveolin and subsequent increase in the activity of eNOS.

Caveolae, caveolin-1 and cavin-1: Emerging roles in pulmonary hypertension

Caveolae are flask-shaped invaginations of cell membrane that play a significant structural and functional role. Caveolae harbor a variety of signaling molecules and serve to receive, concentrate and transmit extracellular signals across the membrane. Caveolins are the main structural proteins residing in the caveolae. Caveolins and another category of newly identified caveolae regulatory proteins, named cavins, are not only responsible for caveolae formation, but also interact with signaling complexes in the caveolae and regulate transmission of signals across the membrane. In the lung, two of the three caveolin isoforms, i.e., cav-1 and -2, are expressed ubiquitously. Cavin protein family is composed of four proteins, named cavin-1 (or PTRF for polymerase I and transcript release factor), cavin-2 (or SDPR for serum deprivation protein response), cavin-3 (or SRBC for sdr-related gene product that binds to-c-kinase) and cavin-4 (or MURC for muscle restricted coiled-coiled protein or cavin-4). All the caveolin and cavin proteins are essential regulators for caveolae dynamics. Recently, emerging evidence suggest that caveolae and its associated proteins play crucial roles in development and progression of pulmonary hypertension. The focus of this review is to outline and discuss the contrast in alteration of cav-1 (cav-1),-2 and cavin-1 (PTRF) expression and downstream signaling mechanisms between human and experimental models of pulmonary hypertension.

Blood cells and endothelial barrier function

The barrier properties of endothelial cells are critical for the maintenance of water and protein balance between the intravascular and extravascular compartments. An impairment of endothelial barrier function has been implicated in the genesis and/or progression of a variety of pathological conditions, including pulmonary edema, ischemic stroke, neurodegenerative disorders, angioedema, sepsis and cancer. The altered barrier function in these conditions is often linked to the release of soluble mediators from resident cells (e.g., mast cells, macrophages) and/or recruited blood cells. The interaction of the mediators with receptors expressed on the surface of endothelial cells diminishes barrier function either by altering the expression of adhesive proteins in the inter-endothelial junctions, by altering the organization of the cytoskeleton, or both. Reactive oxygen species (ROS), proteolytic enzymes (e.g., matrix metalloproteinase, elastase), oncostatin M, and VEGF are part of a long list of mediators that have been implicated in endothelial barrier failure. In this review, we address the role of blood borne cells, including, neutrophils, lymphocytes, monocytes, and platelets, in the regulation of endothelial barrier function in health and disease. Attention is also devoted to new targets for therapeutic intervention in disease states with morbidity and mortality related to endothelial barrier dysfunction.