Hypertonic Treatment Research Articles

A novel tonicity-responsive microRNA miR-23a-5p modulates renal cell survival under osmotic stress through targeting heat shock protein 70 HSPA1B.

There is growing evidence that microRNAs (miRNAs) are implicated in cellular adaptation to osmotic stress, but the underlying osmosignaling pathways are still not completely understood. In this study, we found that a passenger strand miRNA, miR-23a-5p, was significantly downregulated in response to high NaCl treatment in mouse inner medullary collecting duct cells (mIMCD3) through an miRNA profiling assay. The decrease of miR-23a-5p is hypertonicity-dependent and osmotolerant cell type-specific. Knockdown of miR-23a-5p increased cellular survival and proliferation in mIMCD3. In contrast, miR-23a-5p overexpression repressed cell viability and proliferation under hypertonic stress. RNA deep-sequencing revealed that a heat shock protein 70 (HSP70) isoform, HSP70 member 1B (HSPA1B), was significantly increased under hypertonic treatment. Based on the prediction analysis by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and TargetScan, and a further validation via a dual-luciferase assay, HSPA1B was identified as a potential target of miR-23a-5p. Overexpressed miR-23a-5p suppressed HSPA1B, whereas downregulated miR-23a-5p promoted HSPA1B expression in mIMCD3. In addition, an in vivo study demonstrated that there is a reverse correlation between the levels of miR-23a-5p and HSPA1B in mouse renal inner medulla (papilla) that is exposed to extremely high osmolality. In summary, this study elucidates that passenger strand miR-23a-5p is a novel tonicity-responsive miRNA. The downregulation of miR-23a-5p facilitates cellular adaptation to hypertonic stress in mammalian renal cells through modulating HSPA1B.

Hypertonic glucose inhibits growth and attenuates virulence factors of multidrug-resistant Pseudomonas aeruginosa

BackgroundPseudomonas aeruginosa is the most common Gram-negative pathogen responsible for chronic wound infections, such as diabetic foot infections, and further exacerbates the treatment options and cost of such conditions. Hypertonic glucose, a commonly used prolotherapy solution, can accelerate the proliferation of granulation tissue and improve microcirculation in wounds. However, the action of hypertonic glucose on bacterial pathogens that infect wounds is unclear. In this study, we investigated the inhibitory effects of hypertonic glucose on multidrug-resistant P. aeruginosa strains isolated from diabetic foot infections. Hypertonic glucose represents a novel approach to control chronic wound infections caused by P. aeruginosa.ResultsFour multidrug-resistant P. aeruginosa clinical strains isolated from diabetic foot ulcers from a tertiary hospital in China and the reference P. aeruginosa PAO1 strain were studied. Hypertonic glucose significantly inhibited the growth, biofilm formation, and swimming motility of P. aeruginosa clinical strains and PAO1. Furthermore, hypertonic glucose significantly reduced the production of pyocyanin and elastase virulence factors in P. aeruginosa. The expression of major quorum sensing genes (lasI, lasR, rhlI, and rhlR) in P. aeruginosa were all downregulated in response to hypertonic glucose treatment. In a Galleria mellonella larvae infection model, the administration of hypertonic glucose was shown to increase the survival rates of larvae infected by P. aeruginosa strains (3/5).ConclusionsHypertonic glucose inhibited the growth, biofilm formation, and swimming motility of P. aeruginosa, as well as reduced the production of virulence factors and quorum sensing gene expression. Further studies that investigate hypertonic glucose therapy should be considered in treating chronic wound infections.

Calcium-Free and Cytochalasin B Treatment Inhibits Blastomere Fusion in 2-Cell Stage Embryos for the Generation of Floxed Mice via Sequential Electroporation.

The generation of conditional knockout mice using the Cre-loxP system is advantageous for the functional analysis of genes. Flanked by two loxP sites (floxed) mice can be directly obtained from fertilized eggs by the CRISPR/Cas9 genome editing system. We previously reported that sequential knock-in (KI) of each loxP site by electroporation (EP) at the 1- and 2-cell embryonic stages increases the number of mice with floxed alleles compared with simultaneous KI. However, EP at the 2-cell stage frequently induced blastomere fusion. These fused embryos cannot develop to term because they are tetraploidized. In this study, we examined the following three conditions to inhibit blastomere fusion by EP at the 2-cell stage: (1) hypertonic treatment, (2) Calcium (Ca2+)-free treatment, and (3) actin polymerization inhibition. Hypertonic treatment of 2-cell stage embryos prevented blastomere fusion and facilitated blastocyst development; however, KI efficiency was decreased. Ca2+-free treatment and actin polymerization inhibition by cytochalasin B (CB) reduced fusion rate, and did not have negative effects on development and KI efficiency. These results suggest that Ca2+-free and CB treatment at the 2-cell stage is effective to generate floxed mice in combination with a sequential EP method.

Serum Sodium Concentration and Tonicity in Hyperglycemic Crises: Major Influences and Treatment Implications.

Maintenance of the volume of all cells, particularly those of the central nervous system, is critical for their function and survival.1, 2, 3, 4, 5, 6 Tonicity (ie, effective osmolarity) of a solution refers to its property to cause osmotic fluid shifts into or out of cells suspended in it. Direct determination of serum tonicity is not readily available for clinical applications.6 Serum sodium concentration ([Na]S) is the main parameter used as a surrogate value for serum tonicity.5, 6, 7 The only direct information provided by [Na]S is whether serum tonicity is normal (the volume of cells exposed to a serum with normal [Na]S is not affected), low (the volume of cells exposed to a serum with low [Na]S increases by osmotic intracellular transfer of water), or high (the volume of cells exposed to a serum with high [Na]S decreases by osmotic transfer of water out of the cells).6, 7 In a pivotal study, Edelman and coinvestigators identified total body sodium, total body potassium, and total body water as the universal determinants of [Na]S in patients with various states potentially associated with extracellular volume disturbances.8 Abnormalities in [Na]S usually result from changes in the external balance of one of its 3 determinants or a combination thereof. The relations between [Na]S and total body sodium, total body potassium, and total body water have been expressed by various formulas. The original Edelman formula expresses sodium concentration in plasma water.8 The Nguyen and Kurtz formula expresses sodium concentration in plasma, which is essentially equal to [Na]S.9 Nguyen and Kurtz developed their formula by multiplying the components of the Edelman formula by a correction coefficient equal to 0.93, which represents the normal plasma water fraction. The Rose formula, which represents a simplified version of the Edelman formula, expresses [Na]S as the fraction (total body sodium plus total body potassium) over total body water.10 Formulas calculating the tonicity of replacement solutions for correction of dysnatremias applied in clinical practice11, 12, 13, 14 are based on the Rose formula, which will also be the basis of the calculations in this review. The principle that underlies the distribution of body water in the 2 major body‐fluid compartments states that the intracellular/extracellular volume ratio is equal to the intracellular/extracellular solute ratio.15 This relationship is a direct consequence of Peter's osmotic principle, which states that in the steady state, solute concentration (osmolality) is equal in the intracellular and extracellular fluids.16 Total body sodium and potassium represent the major solutes in body fluids: sodium is essentially restricted in the extracellular compartment and potassium in the intracellular compartment. Consequently, total body sodium is a measure of effective extracellular solutes, whereas total body potassium represents the effective intracellular solutes. Hyperglycemic crises create complex disturbances in body water and its distribution between the intracellular and extracellular compartments, in addition to tonicity problems not reflected directly in [Na]S. This review analyzes the pathogenesis and treatment of hyperglycemic hypertonicity.

Ascorbic acid and calcium uptake in pineapple tissue through different sucrose concentrations of impregnation solution

Incorporation of ascorbic acid and calcium in pineapple slices through impregnation processes in isotonic (∼14 °Bx) and hypertonic (50 °Bx) aqueous solution of sucrose was studied. Changes in water content, soluble solids, pH, mechanical and structural properties, ascorbic acid and calcium content in fruit in function of dipping time and impregnation syrup concentration were evaluated. Isotonic treatment was more effective than hypertonic treatment for the calcium and ascorbic acid incorporation in the plant tissue. Under same conditions, the ascorbic acid uptake was greater than calcium uptake. The fruit firmness was reduced during isotonic treatment and increased by osmotic dehydration, without significant effect of the nutrients addition to the impregnation solution. Additionally, changes in some physicochemical properties of impregnation solution in function of the time have been studied. Nutrient content in impregnation solutions did not register significant changes, which would allow its reuse with some conditioning of the soluble solids concentration.

Real-World Data on the Use of Hypertonic Saline Nasal Spray in ENT Practice

Hypertonic saline solutions are in broad medicinal use for treatment of various disorders of nose and paranasal sinuses. This trial aimed at the evaluation of safety and efficacy of a hypertonic saline nasal spray within the scope of routine care in an otorhinolaryngological outpatient setting. One hundred and thirty-six patients were included into this uncontrolled clinical trial and received 2.7% saline solution nasal spray. Symptoms and clinical signs were documented on an ordinal scale of 0–4 during initial and final examination, and both individual symptoms and the sum of symptom scores (clinical sum score) were assessed. Participating patients and physicians furthermore evaluated the clinical benefit of the therapy. Clinical sum score decreased from 13.63 ± 6.65 to 7.85 ± 6.79 (p < 0.001) between initial and final examination, and significant improvements were observed for 10 out of 12 individual symptoms. A clinical benefit was attributed to hypertonic saline treatment by both patients and physicians in more than 50% of the documented cases. Seventy percent of the patients noticed improvement of nasal breathing, and 50% of the patients considered hypertonic saline an alternative to the use of α-sympathomimetics. One adverse event (epistaxis) was reported, whereas 95% of the patients rated the treatment as flawless. Eleven pregnant women and one nursing mother participated in the trial without the occurrence of any negative effect on mother and child. This study substantiates the safe and efficacious use of hypertonic saline nasal spray. Reduction in use of classical decongestants constitutes a valuable and safe therapeutic option for patients for whom use of these drugs is contraindicated.Clinical Trial Register: DRKS-ID: DRKS00010825

Low-chloride versus high-chloride hypertonic solution for the treatment of subarachnoid hemorrhage-related complications (The ACETatE trial): study protocol for a pilot randomized controlled trial

BackgroundAneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening condition that results from a ruptured cerebral vessel. Cerebral edema and vasospasm are common complications and frequently require treatment with hypertonic solutions, in particular hypertonic sodium chloride (NaCl). We have previously shown that hyperchloremia in patients with aSAH given hypertonic NaCl is associated with the development of acute kidney injury (AKI), which leads to higher morbidity and mortality. Our current trial aims to study the effect of two hypertonic solutions with different chloride content on serum chloride concentrations in patients with aSAH who are at risk for AKI.MethodsA low ChloridE hyperTonic solution for brain Edema (ACETatE) is a single center, double-blinded, double-dummy pilot trial comparing bolus doses of 23.4% NaCl and 16.4% NaCl/Na-Acetate for the treatment of cerebral edema in patients with aSAH. All patients will be enrolled within 36 h following admission. Randomization will occur once patients who receive hypertonic treatment for cerebral edema develop hyperchloremia (serum Cl− concentration ≥ 109 mmol/L). Subsequent treatment will consist of either NaCl 23.4% or NaCl/Na-Acetate 16.4%. The primary outcome of this study will be the change in serum Cl− concentrations during treatment. Secondary outcomes will include incidence of AKI, mortality, changes in intracranial pressure, and extent of hypernatremia.DiscussionIn patients with aSAH, hyperchloremia is a known risk factor for subsequent development of AKI. The primary goal of this pilot study is to determine the effect of two hypertonic solutions with different Cl− content on serum Cl− concentrations in patients with aSAH who have already developed hyperchloremia. Data will be collected prospectively to determine the extent to which the choice of hypertonic saline solution affects subsequent serum Cl− concentrations and the occurrence of AKI. This approach will allow us to obtain preliminary data to design a large randomized trial assessing the effects of chloride-sparing hypertonic solutions on development of AKI in patients with SAH. This pilot study is the first to prospectively evaluate the relationship between hypertonic solution chloride content and its effect on serum electrolytes and renal function in aSAH patients at risk of AKI due to hyperchloremia.Trial registrationClinicaltrials.gov, NCT03204955. Registered on 28 June 2017.

Effects of Thickness on Corneal Biomechanical Properties Using Optical Coherence Elastography.

Measured corneal biomechanical properties are driven by intraocular pressure, tissue thickness, and inherent material properties. We demonstrate tissue thickness as an important factor in the measurement of corneal biomechanics that can confound short-term effects due to UV riboflavin cross-linking (CXL) treatment. We isolate the effects of tissue thickness on the measured corneal biomechanical properties using optical coherence elastography by experimentally altering the tissue hydration state and stiffness. Dynamic optical coherence elastography was performed using phase-sensitive optical coherence tomography imaging to quantify the tissue deformation dynamics resulting from a spatially discrete, low-force air pulse (150-μm spot size; 0.8-millisecond duration; <10 Pa [<0.08 mmHg]). The time-dependent surface deformation is characterized by a viscoelastic tissue recovery response, quantified by an exponential decay constant-relaxation rate. Ex vivo rabbit globes (n = 10) with fixed intraocular pressure (15 mmHg) were topically instilled every 5 minutes with 0.9% saline for 60 minutes and 20% dextran for another 60 minutes. Measurements were made after every 20 minutes to determine the central corneal thickness (CCT) and the relaxation rates. Cross-linking treatment was performed on another 13 eyes, applying isotonic riboflavin (n = 6) and hypertonic riboflavin (n = 7) every 5 minutes for 30 minutes, followed by UV irradiation (365 nm, 3 mW/cm) for 30 minutes while instilling riboflavin. Central corneal thickness and relaxation rates were obtained before and after CXL treatment. Corneal thickness was positively correlated (R = 0.9) with relaxation rates. In the CXL-treated eyes, isotonic riboflavin did not affect CCT and showed a significant increase in relaxation rates (+10%; P = .01) from 2.29 ms to 2.53 ms. Hypertonic riboflavin showed a significant CCT decrease (-31%; P = .01) from 618 μm to 429 μm but showed little change in relaxation rates after CXL treatment. Corneal thickness and stiffness are correlated positively. A higher relaxation rate implied stiffer material properties after isotonic CXL treatment. Hypertonic CXL treatment results in a stiffness decrease that offsets the stiffness increase with CXL treatment.

Osmotic Compounds Enhance Antibiotic Efficacy against Acinetobacter baumannii Biofilm Communities.

Biofilm-associated infections are a clinical challenge, in part because a hydrated matrix protects the bacterial community from antibiotics. Herein, we evaluated how different osmotic compounds (maltodextrin, sucrose, and polyethylene glycol [PEG]) enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities. Established (24-h) test tube biofilms (strain ATCC 17978) were treated with osmotic compounds in the presence or absence of 10× the MIC of different antibiotics (50 μg/ml tobramycin, 20 μg/ml ciprofloxacin, 300 μg/ml chloramphenicol, 30 μg/ml nalidixic acid, or 100 μg/ml erythromycin). Combining antibiotics with hypertonic concentrations of the osmotic compounds for 24 h reduced the number of biofilm bacteria by 5 to 7 log (P < 0.05). Increasing concentrations of osmotic compounds improved the effect, but there was a trade-off with increasing solution viscosity, whereby low-molecular-mass compounds (sucrose, 400-Da PEG) worked better than higher-mass compounds (maltodextrin, 3,350-Da PEG). Ten other A. baumannii strains were similarly treated with 400-Da PEG and tobramycin, resulting in a mean 2.7-log reduction in recoverable bacteria compared with tobramycin treatment alone. Multivariate regression models with data from different osmotic compounds and nine antibiotics demonstrated that the benefit from combining hypertonic treatments with antibiotics is a function of antibiotic mass and lipophilicity (r2 > 0.82; P < 0.002), and the relationship was generalizable for biofilms formed by A. baumannii and Escherichia coli K-12. Augmenting topical antibiotic therapies with a low-mass hypertonic treatment may enhance the efficacy of antibiotics against wound biofilms, particularly when using low-mass hydrophilic antibiotics.IMPORTANCE Biofilms form a barrier that protects bacteria from environmental insults, including exposure to antibiotics. We demonstrated that multiple osmotic compounds can enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities, but viscosity is a limiting factor, and the most effective compounds have lower molecular mass. The synergism between osmotic compounds and antibiotics is also dependent on the hydrophobicity and mass of the antibiotics. The statistical models presented herein provide a basis for predicting the optimal combination of osmotic compounds and antibiotics against surface biofilms communities.

The curative effect observation of nasal irrigation by hypertonic salinein treatment of infant acute rhinosinusitis

The curative effect observation of nasal irrigation by hypertonic salinein treatment of infant acute rhinosinusitis

Impact of Moderate Hyperchloremia on Clinical Outcomes in Intracerebral Hemorrhage Patients Treated With Continuous Infusion Hypertonic Saline: A Pilot Study.

Hyperchloremia has been associated with increased morbidity and mortality in critically ill patients. While previous research has demonstrated an association between hypertonic saline and hyperchloremia, limited data exist in neurocritical care patients. The objective of this study is to determine the impact of moderate hyperchloremia (chloride ≥ 115 mmol/L) on clinical outcomes in intracerebral hemorrhage patients treated with continuous IV infusion 3% hypertonic saline. Multicenter, retrospective, propensity-matched cohort study. Neurocritical care units at two academic medical centers with dedicated neurocritical care teams and comprehensive stroke center designation. Intracerebral hemorrhage patients discharged between September 2011 and September 2015 were evaluated and matched 1:1 based on propensity scoring. Continuous IV infusion 3% hypertonic saline. A total of 219 patients were included in the unmatched cohort (143 moderate hyperchloremia and 76 nonhyperchloremia) and 100 patients in the propensity-matched cohort. In-hospital mortality was significantly higher in those who developed moderate hyperchloremia in a propensity-matched cohort (34% vs 14%; p = 0.02). Moderate hyperchloremia independently predicted in-hospital mortality in multivariable logistic regression analysis (odds ratio, 4.4 [95% CI, 1.4-13.5]; p = 0.01). We observed higher rates of in-hospital mortality in patients who developed moderate hyperchloremia during treatment with continuous IV infusion 3% hypertonic saline, with moderate hyperchloremia independently predicting in-hospital mortality. These results suggest that chloride values should be monitored closely during hypertonic saline treatment as moderate elevations may impact outcomes in intracerebral hemorrhage patients.

Effect of Nebulized Hypertonic Saline Treatment in Emergency Departments on the Hospitalization Rate for Acute Bronchiolitis

Acute bronchiolitis is the leading cause of hospitalization among infants. Previous studies, underpowered to examine hospital admission, have found a limited benefit of nebulized hypertonic saline (HS) treatment in the pediatric emergency department (ED). To examine whether HS nebulization treatment would decrease the hospital admission rate among infants with a first episode of acute bronchiolitis. The Efficacy of 3% Hypertonic Saline in Acute Viral Bronchiolitis (GUERANDE) study was a multicenter, double-blind randomized clinical trial on 2 parallel groups conducted during 2 bronchiolitis seasons (October through March) from October 15, 2012, through April 15, 2014, at 24 French pediatric EDs. Among the 2445 infants (6 weeks to 12 months of age) assessed for inclusion, 777 with a first episode of acute bronchiolitis with respiratory distress and no chronic medical condition were included. Two 20-minute nebulization treatments of 4 mL of HS, 3%, or 4 mL of normal saline (NS), 0.9%, given 20 minutes apart. Hospital admission rate in the 24 hours after enrollment. Of the 777 infants included in the study (median age, 3 months; interquartile range, 2-5 months; 468 [60.2%] male), 385 (49.5%) were randomized to the HS group and 387 (49.8%) to the NS group (5 patients did not receive treatment). By 24 hours, 185 of 385 infants (48.1%) in the HS group were admitted compared with 202 of 387 infants (52.2%) in the NS group. The risk difference for hospitalizations was not significant according to the mixed-effects regression model (adjusted risk difference, -3.2%; 95% CI, -8.7% to 2.2%; P = .25). The mean (SD) Respiratory Distress Assessment Instrument score improvement was greater in the HS group (-3.1 [3.2]) than in the NS group (-2.4 [3.3]) (adjusted difference, -0.7; 95% CI, -1.2 to -0.2; P = .006) and similarly for the Respiratory Assessment Change Score. Mild adverse events, such as worsening of cough, occurred more frequently among children in the HS group (35 of 392 [8.9%]) than among those in the NS group (15 of 384 [3.9%]) (risk difference, 5.0%; 95% CI, 1.6%-8.4%; P = .005), with no serious adverse events. Nebulized HS treatment did not significantly reduce the rate of hospital admissions among infants with a first episode of acute moderate to severe bronchiolitis who were admitted to the pediatric ED relative to NS, but mild adverse events were more frequent in the HS group. clinicaltrials.gov Identifier: NCT01777347.

Hyperosmotic stress induces ATP release and changes in P2X7 receptor levels in human corneal and conjunctival epithelial cells.

Tear hyperosmolarity is a key event in dry eye. In this work, we analyzed whether hyperosmolar challenge induces ATP release on the ocular surface. Moreover, as extracellular ATP can activate P2X7 receptor, the changes in P2X7 protein levels and its involvement in pathological process triggered by hypertonic treatment were also examined. High-performance liquid chromatography analysis revealed that ATP levels significantly increased in human corneal and conjunctival epithelial cells exposed to hyperosmotic challenge as well as in dry eye patients as compared to control subjects. A significant reduction in cell viability was detected after hyperosmolar treatment, indicating that the rise in ATP release was mainly due to cell lysis/death. Additionally, vesicular nucleotide transporter was identified in both cell lines and their protein expression was upregulated in hypertonic media. P2X7 receptor truncated form together with the full-length form was identified in both cell lines, and experiments using specific antagonist and agonist for P2X7 indicated that this receptor did not mediate cell death induced by hyperosmolar stress. In conclusion, hyperosmotic stress induces ATP release. Extracellular ATP can activate P2X7 receptor leading to cytotoxicity in many cells/tissues; however, this does not occur in human corneal and conjunctival epithelial cells. In these cells, the presence of P2X7 receptor truncated form together with the full-length form hinders a P2X7 apoptotic behavior on the ocular surface.

Liposomal internal viscosity affects the fate of membrane deformation induced by hypertonic treatment.

Artificial lipid membranes have been utilized to understand the physical mechanisms of the deformation patterns of live cells. However, typical artificial membrane systems contain only dilute components compared to those in the cytoplasm of live cells. By using giant unilamellar liposomes containing dense protein solutions similar to those in live cells, we here reveal that viscosity derived from internal crowding affects the deformation patterns of lipid membranes. After hypertonic treatment, liposome deformation patterns transitioned from budding to tubing when the initial internal macromolecular concentrations were increased. Remarkably, instead of observing different transition concentrations between two species of macromolecules, the viscosity at the transition concentration was found to be similar. Further analyses clearly demonstrated that the internal viscosity affects the deformation patterns of lipid membranes induced by hypertonic treatment. These results indicate that the viscosity of the cytoplasm is a key factor in determining cell deformation, and suggest the association of a process involving dynamic instability, such as a viscous fingering phenomenon, during the determination of deformation patterns by hypertonic treatment.

Direct monitoring of pulmonary disease treatment biomarkers using plasmonic gold nanorods with diffusion-sensitive OCT.

The solid concentration of pulmonary mucus (wt%) is critical to respiratory health. In patients with respiratory disease, such as Cystic Fibrosis (CF) and Chronic Obstructive Pulmonary Disorder (COPD), mucus hydration is impaired, resulting in high wt%. Mucus with high wt% is a hallmark of pulmonary disease that leads to obstructed airways, inflammation, and infection. Methods to measure mucus hydration in situ and in real-time are needed for drug development and personalized therapy. We employed plasmonic gold nanorod (GNR) biosensors that intermittently collide with macromolecules comprising the mucus mesh as they self-diffuse, such that GNR translational diffusion (DT) is sensitive to wt%. GNRs are attractive candidates for bioprobes due to their anisotropic optical scattering that makes them easily distinguishable from native tissue using polarization-sensitive OCT. Using principles of heterodyne dynamic light scattering, we developed diffusion-sensitive optical coherence tomography (DS-OCT) to spatially-resolve changing DT in real-time. DS-OCT enables, for the first time, direct monitoring of changes in nanoparticle diffusion rates that are sensitive to nanoporosity with spatial and temporal resolutions of 4.7 μm and 0.2 s. DS-OCT therefore enables us to measure spatially-resolved changes in mucus wt% over time. In this study, we demonstrate the applicability of DS-OCT on well-differentiated primary human bronchial epithelial cells during a clinical mucus-hydrating therapy, hypertonic saline treatment (HST), to reveal, for the first time, mucus mixing, cellular secretions, and mucus hydration on the micrometer scale that translate to long-term therapeutic effects.

Intravital microscopy of mucus transport in mice provides mechanistic insight into hypertonic saline treatment of Cystic Fibrosis

In clinical studies of cystic fibrosis (CF) patients, inhalation of 7% NaCl was found to be superior compared to 0.9%, which is attributed to increased hydration of mucus. However, mechanistic insight has been hampered by the inability to visualize mucus transport in vivo with microscopic resolution.

Towards automated evaluation of mucus transport measured by microscopic OCT (mOCT) during hypertonic saline treatment of Cystic Fibrosis

Towards automated evaluation of mucus transport measured by microscopic OCT (mOCT) during hypertonic saline treatment of Cystic Fibrosis

Osmotherapy With Hypertonic Saline Attenuates Global Cerebral Edema Following Experimental Cardiac Arrest via Perivascular Pool of Aquaporin-4.

We tested the hypothesis that osmotherapy with hypertonic saline attenuates cerebral edema following experimental cardiac arrest and cardiopulmonary resuscitation by exerting its effect via the perivascular pool of aquaporin-4. We used mice with targeted disruption of the gene encoding α-syntrophin (α-Syn) that demonstrate diminished perivascular aquaporin-4 pool but retain the non-endfoot and ependymal pools. Laboratory animal study. University animal research laboratory. Isoflurane-anesthetized adult male wild-type C57B/6 or α-Syn mice were subjected to cardiac arrest/cardiopulmonary resuscitation and treated with either a continuous IV infusion of 0.9% saline or various concentrations of hypertonic saline. Serum osmolality, regional brain water content, blood-brain barrier disruption, and aquaporin-4 protein expression were determined at 24 hours after cardiac arrest/cardiopulmonary resuscitation. Hypertonic saline (7.5%) treatment significantly attenuated water content in the caudoputamen complex and cortex compared with 0.9% saline treatment in wild-type mice subjected to cardiac arrest/cardiopulmonary resuscitation. In contrast, in α-Syn mice subjected to cardiac arrest/cardiopulmonary resuscitation, 7.5% hypertonic saline treatment did not attenuate water content. Treatment with 7.5% hypertonic saline attenuated blood-brain barrier disruption at 24 hours following cardiac arrest/cardiopulmonary resuscitation in wild-type mice but not in α-Syn mice. Total aquaporin-4 protein expression was not different between 0.9% saline and hypertonic saline-treated wild-type mice. Following experimental cardiac arrest/cardiopulmonary resuscitation: 1) continuous hypertonic saline therapy maintained to achieve serum osmolality of ≈ 350 mOsm/L is beneficial for the treatment of cerebral edema; 2) perivascular pool of aquaporin-4 plays a critical role in water egress from brain; and 3) hypertonic saline attenuates blood-brain barrier disruption via perivascular aquaporin-4 pool.

Prophylactic Use of Nebulized Hypertonic Saline in Mechanically Ventilated Children: A Randomized Blinded Pilot Study.

Mucolytic agents, such as nebulized hypertonic saline, may improve airway clearance and shorten the duration of mechanical ventilation, but prospective blinded studies in children undergoing mechanical ventilation are lacking. Children <18 y old who had been intubated for <12 h and had an expected duration of mechanical ventilation of >48 additional h were prophylactically given 3 mL of either nebulized hypertonic saline or placebo (0.9% saline) 4 times/d. The primary outcome was duration of mechanical ventilation. Ventilator parameters and the presence of wheezing were recorded before and after study drug administration. The duration of mechanical ventilation was significantly longer in children treated with hypertonic saline (208.1 [interquartile range 136.3-319.8] h) versus those treated with placebo (129.5 [interquartile range 74.4-146.1] h) (P = .03 by Wilcoxon rank-sum test). After adjusting for baseline levels of PEEP, the duration of mechanical ventilation did not differ between groups. Mechanical ventilation parameters, including dead space and dynamic compliance, did not differ between measurements taken before study drug administration versus measurements taken after. New onset wheezing following study drug administration was rare (1.0% with hypertonic saline vs 3.0% with placebo, P = .36 by chi-square test). Administering prophylactic nebulized hypertonic saline to mechanically ventilated children did not improve clinically relevant outcomes, including duration of mechanical ventilation. Wheezing after hypertonic saline treatment was rare.

Brivaracetam augments short-term depression and slows vesicle recycling.

Brivaracetam (BRV) decreases seizure activity in a number of epilepsy models and binds to the synaptic vesicle glycoprotein 2A (SV2A) with a higher affinity than the antiepileptic drug levetiracetam (LEV). Experiments were performed to determine if BRV acted similarly to LEV to induce or augment short-term depression (STD) under high-frequency neuronal stimulation and slow synaptic vesicle recycling. Electrophysiologic field excitatory postsynaptic potential (fEPSP) recordings were made from CA1 synapses in rat hippocampal slices loaded with BRV or LEV during intrinsic activity or with BRV actively loaded during hypertonic stimulation. STD was examined in response to 5 or 40 Hz stimulus trains. Presynaptic release of FM1-43 was visualized using two-photon microscopy to assess drug effects upon synaptic vesicle mobilization. When hippocampal slices were incubated in 0.1-30 μm BRV or 30 μm-1 mm LEV for 3 h, the relative CA1 field EPSPs decreased over the course of a high-frequency train of stimuli more than for control slices. This STD was frequency- and concentration-dependent, with BRV being 100-fold more potent than LEV. The extent of STD depended on the length of the incubation time for both drugs. Pretreatment with LEV occluded the effects of BRV. Repeated hypertonic sucrose treatments and train stimulation successfully unloaded BRV from recycling vesicles and reversed BRVs effects on STD, as previously reported for LEV. At their maximal concentrations, BRV slowed FM1-43 release to a greater extent than in slices loaded with LEV during prolonged stimulation. BRV, similar to LEV, entered into recycling synaptic vesicles and produced a frequency-dependent decrement of synaptic transmission at 100-fold lower concentrations than LEV. In addition, BRV slowed synaptic vesicle mobilization more effectively than LEV, suggesting that these drugs may modify multiple functions of the synaptic vesicle protein SV2A to curb synaptic transmission and limit epileptic activity.