Randomized controlled study of aerosolized hypertonic xylitol versus hypertonic saline in hospitalized patients with pulmonary exacerbation of cystic fibrosis

Natural intestinal metabolite xylitol reduces BRD4 levels to mitigate renal fibrosis

Renal fibrosis is a typical pathological change from chronic kidney disease (CKD) to end-stage renal failure, which presents significant challenges in prevention and treatment. The progression of renal fibrosis is closely associated with the "gut-kidney axis," therefore, although clinical intervention to modulate the "gut-kidney axis" imbalance associated with renal fibrosis brings hope for its treatment. In this study, we first identified the close relationship between renal fibrosis development and the intestinal microenvironment through fecal microtransplantation and non-absorbable antibiotics experiments. Then, we analyzed the specific connection between the intestinal microenvironment and renal fibrosis using microbiomics and metabolomics, screening for the differential intestinal metabolite. Potential metabolite action targets were initially identified through network simulation of molecular docking and further verified by molecular biology experiment. We used flow cytometry, TUNEL apoptosis staining, immunohistochemistry, and Western blotting to assess renal injury and fibrosis extent, exploring the potential role of gut microbial metabolite in renal fibrosis development. We discovered that CKD-triggered alterations in the intestinal microenvironment exacerbate renal injury and fibrosis. When metabolomic analysis was combined with experiments in vivo, we found that the differential metabolite xylitol delays renal injury and fibrosis development. We further validated this hypothesis at the cellular level. Mechanically, bromodomain-containing protein 4 (BRD4) protein exhibits strong binding with xylitol, and xylitol alleviates renal fibrosis by inhibiting BRD4 and its downstream transforming growth factor-β (TGF-β) pathway. In summary, our findings suggest that the natural intestinal metabolite xylitol mitigates renal fibrosis by inhibiting the BRD4-regulated TGF-β pathway.

Nebulised hypertonic saline for cystic fibrosis

BACKGROUND

Hypertonic saline enhances mucociliary clearance and may lessen the destructive inflammatory process in the airways. This is an update of a previously published review.

OBJECTIVES

To investigate efficacy and tolerability of nebulised hypertonic saline treatment in people with cystic fibrosis (CF) compared to placebo or other treatments that enhance mucociliary clearance.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Cystic Fibrosis Trials Register, comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. We also searched ongoing trials databases. Most recent search: 25 April 2022.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials assessing hypertonic saline compared to placebo or other mucolytic therapy, for any duration or dose regimen in people with CF (any age or disease severity).

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed all identified trials and data, and assessed trial quality. We assessed the certainty of the evidence using GRADE. For cross-over trials we stipulated a one-week washout period. We planned to use results from a paired analysis in the review, but this was only possible in one trial. For other cross-over trials, we chose to treat the trials as if they were parallel.

MAIN RESULTS

We included 24 trials (1318 participants, aged one month to 56 years); we excluded 29 trials, two trials are ongoing and six are awaiting classification. We judged 15 of the 24 included trials to have a high risk of bias due to participants' ability to discern the taste of the solutions. Hypertonic saline 3% to 7% versus placebo (stable disease) We are uncertain whether the regular use of nebulised hypertonic saline in stable lung disease leads to an improvement in forced expiratory volume in one second (FEV1) % predicted at four weeks, (mean difference (MD) 3.30%, 95% confidence interval (CI) 0.71 to 5.89; 4 trials, 246 participants; very low-certainty evidence). In preschool children we found no difference in lung clearance index (LCI) at four weeks, but a small improvement after 48 weeks of treatment with hypertonic saline compared to isotonic saline (MD -0.60, 95% CI -1.00 to -0.19; 2 trials, 192 participants). We are also uncertain whether hypertonic saline made a difference to mucociliary clearance, pulmonary exacerbations or adverse events compared to placebo. Hypertonic saline versus control (acute exacerbation) Two trials compared hypertonic saline to control, but only one provided data. There may be little or no difference in lung function measured by FEV1 % predicted after hypertonic saline compared to isotonic saline (MD 5.10%, 95% CI -14.67 to 24.87; 1 trial, 130 participants). Neither trial reported any deaths or measures of sputum clearance. There were no serious adverse events. Hypertonic saline versus rhDNase Three trials compared a similar dose of hypertonic saline to recombinant deoxyribonuclease (rhDNase); two trials (61 participants) provided data for inclusion in the review. We are uncertain whether there was an effect of hypertonic saline on FEV1 % predicted after three weeks (MD 1.60%, 95% CI -7.96 to 11.16; 1 trial, 14 participants; very low-certainty evidence). At three months, rhDNase may lead to a greater increase in FEV1 % predicted than hypertonic saline (5 mL twice daily) at 12 weeks in participants with moderate to severe lung disease (MD 8.00%, 95% CI 2.00 to 14.00; low-certainty evidence). We are uncertain whether adverse events differed between the two treatments. No deaths were reported. Hypertonic saline versus amiloride One trial (12 participants) compared hypertonic saline to amiloride but did not report on most of our outcomes. The trial found that there was no difference between treatments in measures of sputum clearance (very low-certainty evidence). Hypertonic saline compared with sodium-2-mercaptoethane sulphonate (Mistabron®) One trial (29 participants) compared hypertonic saline to sodium-2-mercaptoethane sulphonate. The trial did not measure our primary outcomes. There was no difference between treatments in any measures of sputum clearance, courses of antibiotics or adverse events (very low-certainty evidence). Hypertonic saline versus mannitol One trial (12 participants) compared hypertonic saline to mannitol, but did not report lung function at relevant time points for this review; there were no differences in sputum clearance, but mannitol was reported to be more 'irritating' (very low-certainty evidence). Hypertonic saline versus xylitol Two trials compared hypertonic saline to xylitol, but we are uncertain whether there is any difference in FEV1 % predicted or median time to exacerbation between groups (very low-certainty evidence). No other outcomes were reported in the review. Hypertonic saline 7% versus hypertonic saline 3% We are uncertain whether there was an improvement in FEV1 % predicted after treatment with 7% hypertonic saline compared with 3% (very low-certainty evidence).

AUTHORS' CONCLUSIONS

We are very uncertain if regular use of nebulised hypertonic saline by adults and children over the age of 12 years with CF results in an improvement in lung function after four weeks (three trials; very low-certainty evidence); there was no difference seen at 48 weeks (one trial; low-certainty evidence). Hypertonic saline improved LCI modestly in children under the age of six years. Evidence from one small cross-over trial in children indicates that rhDNase may lead to better lung function than hypertonic saline at three months; qualifying this, we highlight that while the study did demonstrate that the improvement in FEV1 was greater with daily rhDNase, there were no differences seen in any of the secondary outcomes. Hypertonic saline does appear to be an effective adjunct to physiotherapy during acute exacerbations of lung disease in adults. However, for the outcomes assessed, the certainty of the evidence ranged from very low to low at best, according to the GRADE criteria. The role of hypertonic saline in conjunction with cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy now needs to be considered, and future research needs to focus on this aspect.

Endotracheal nebulization of gold nanoparticles for noninvasive pulmonary drug delivery

Background & aims: Gold nanoparticles (AuNPs) are useful tools for noninvasive drug delivery. AuNP nebulization has shown poor deposition results, and AuNP tracking postadministration has involved methods inapplicable to clinical settings. The authors propose an intratracheal delivery method for minimal AuNP loss and computed tomography scans for noninvasive tracking. Materials & methods: Through high-frequency and directed nebulization postendotracheal intubation, the authors treated rats with AuNPs. Results & conclusion: The study showed a dose-dependent and bilateral distribution of AuNPs causing no short-term distress to the animal or risk of airway inflammation. The study demonstrated that AuNPs do not deposit in abdominal organs and show targeted delivery to human lung fibroblasts, offering a specific and noninvasive strategy for respiratory diseases requiring long-term therapies.

Anti-Pseudomonas aeruginosa Vaccines and Therapies: An Assessment of Clinical Trials

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes high morbidity and mortality in cystic fibrosis (CF) and immunocompromised patients, including patients with ventilator-associated pneumonia (VAP), severely burned patients, and patients with surgical wounds. Due to the intrinsic and extrinsic antibiotic resistance mechanisms, the ability to produce several cell-associated and extracellular virulence factors, and the capacity to adapt to several environmental conditions, eradicating P. aeruginosa within infected patients is difficult. Pseudomonas aeruginosa is one of the six multi-drug-resistant pathogens (ESKAPE) considered by the World Health Organization (WHO) as an entire group for which the development of novel antibiotics is urgently needed. In the United States (US) and within the last several years, P. aeruginosa caused 27% of deaths and approximately USD 767 million annually in health-care costs. Several P. aeruginosa therapies, including new antimicrobial agents, derivatives of existing antibiotics, novel antimicrobial agents such as bacteriophages and their chelators, potential vaccines targeting specific virulence factors, and immunotherapies have been developed. Within the last 2-3 decades, the efficacy of these different treatments was tested in clinical and preclinical trials. Despite these trials, no P. aeruginosa treatment is currently approved or available. In this review, we examined several of these clinicals, specifically those designed to combat P. aeruginosa infections in CF patients, patients with P. aeruginosa VAP, and P. aeruginosa-infected burn patients.

Combination and nanotechnology based pharmaceutical strategies for combating respiratory bacterial biofilm infections

Respiratory infections are one of the major global health problems. Among them, chronic respiratory infections caused by biofilm formation are difficult to treat because of both drug tolerance and poor drug penetration into the complex biofilm structure. A major part of the current research on combating respiratory biofilm infections have been focused on destroying the matrix of extracellular polymeric substance and eDNA of the biofilm or promoting the penetration of antibiotics through the extracellular polymeric substance via delivery technologies in order to kill the bacteria inside. There are also experimental data showing that certain inhaled antibiotics with simple formulations can effectively penetrate EPS to kill surficially located bacteria and centrally located dormant bacteria or persisters. This article aims to review recent advances in the pharmaceutical strategies for combating respiratory biofilm infections with a focus on nanotechnology-based drug delivery approaches. The formation and characteristics of bacterial biofilm infections in the airway mucus are presented, which is followed by a brief review on the current clinical approaches to treat respiratory biofilm infections by surgical removal and antimicrobial therapy, and also the emerging clinical treatment approaches. The current combination of antibiotics and non-antibiotic adjuvants to combat respiratory biofilm infections are also discussed.

State-of-the-Art Review of The Application and Development of Various Methods of Aerosol Therapy

Aerosol therapy is a rapidly developing field of science. Due to a number of advantages, the administration of drugs to the body with the use of aerosol therapy is becoming more and more popular. Spraying drugs into the patient's lungs has a significant advantage over other methods of administering drugs to the body, including injection and oral methods. In order to conduct proper and effective aerosol therapy, it is necessary to become familiar with the basic principles and applications of aerosol therapy under various conditions. The effectiveness of inhalation depends on many factors, but most of all on: the physicochemical properties of the sprayed system, the design of the medical inhaler and its correct application, the dynamics of inhalation (i.e. the frequency of breathing and the volume of inhaled air). It is worth emphasizing that respiratory system diseases are one of the most frequently occurring and fastest growing diseases in the world. Accordingly, in recent years, a significant increase in the number of new spraying devices and pharmaceutical drugs for spraying has appeared on the market. It should also be remembered that the process of spraying a liquid is a complicated and complex process, and its efficiency is very often characterized by the use of micro- and macro parameters (including average droplet diameters or the spectrum of droplet diameter distribution). In order to determine the effectiveness of the atomization process and in the delivery of drugs to the patient's respiratory tract, the analysis of the size of the generated aerosol droplets is most often performed. Based on the proposed literature review, it has been shown that many papers dealt with the issues related to aerosol therapy, the selection of an appropriate spraying device, the possibility of modifying the spraying devices in order to increase the effectiveness of inhalation, and the possibility of occurrence of certain discrepancies resulting from the use of various measurement methods to determine the characteristics of the generated aerosol. The literature review presented in the paper was prepared in order to better understand the spraying process. Moreover, it can be helpful in choosing the right medical inhaler for a given liquid with specific rheological properties. The experimental data contained in this study are of great cognitive importance and may be of interest to entities involved in pharmaceutical product engineering (in particular in the case of the production of drugs containing liquids with complex rheological properties).

Rheological effects of hypertonic saline and sodium bicarbonate solutions on cystic fibrosis sputum in vitro

BACKGROUND

Cystic fibrosis (CF) is a life-threatening multiorgan genetic disease, particularly affecting the lungs, where recurrent infections are the main cause of reduced life expectancy. In CF, mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein impair transepithelial electrolyte and water transport, resulting in airway dehydration, and a thickening of the mucus associated with abnormal viscoelastic properties. Our aim was to develop a rheological method to assess the effects of hypertonic saline (NaCl) and NaHCO₃ on CF sputum viscoelasticity in vitro, and to identify the critical steps in sample preparation and in the rheological measurements.

METHODS

Sputum samples were mixed with hypertonic salt solutions in vitro in a ratio of either 10:4 or 10:1. Distilled water was applied as a reference treatment. The rheological properties of sputum from CF patients, and the effects of these in vitro treatments, were studied with a rheometer at constant frequency and strain, followed by frequency sweep tests, where storage modulus (G'), loss modulus (G″) and loss factor were determined.

RESULTS

We identified three distinct categories of sputum: (i) highly elastic (G' > 100,000 Pa), (ii) elastic (100,000 Pa > G' > 1000 Pa), and (iii) viscoelastic (G' < 1000). At the higher additive ratio (10:4), all of the added solutions were found to significantly reduce the gel strength of the sputum, but the most pronounced changes were observed with NaHCO₃ (p < 0.001). Samples with high elasticity exhibited the greatest changes while, for less elastic samples, a weakening of the gel structure was observed when they were treated with water or NaHCO₃, but not with NaCl. For the viscoelastic samples, the additives did not cause significant changes in the parameters. When the lower additive ratio (10:1) was used, the mean values of the rheological parameters usually decreased, but the changes were not statistically significant.

CONCLUSION

Based on the rheological properties of the initial sputum samples, we can predict with some confidence the treatment efficacy of each of the alternative additives. The marked differences between the three categories suggest that it is advisable to evaluate each sample individually using a rheological approach such as that described here.