Controlling the Release of Proteins from Therapeutic Nanofibers: The Effect of Fabrication Modalities on Biocompatibility and Antimicrobial Activity of Lysozyme.

Therapeutic application of pharmacologically active proteins requires advanced drug delivery systems for stabilizing their activity and preventing denaturation during storage and patient treatment. Depending on their clinical target, controlled drug release is often required to achieve the intended therapeutic effect. In this context, electrospun nanofibers gained considerable attention. However, even though immediate drug release from such fibers can easily be realized, fiber mat fabrication providing long-term controlled protein release still bares challenges.In this study, lysozyme was encapsulated in poly(vinyl alcohol) fibers followed by post-modification with MeOH, glutaraldehyde vapor, or UV light. Subsequently, a systematic investigation of the effect of these post-modification treatments on the physicochemical properties of the fibers and the stability and release kinetics of lysozyme was performed. MeOH treatment did not affect lysozyme release kinetics compared to untreated fibers, whereas glutaraldehyde vapor and UV light treatment prolonged the drug release. Infrared spectroscopy revealed cross-linking of the polymer by glutaraldehyde vapor, which reduced the lysozyme release from the fibers. Further, protein activity was significantly reduced for fibers treated with glutaraldehyde vapor and UV light. In addition, reduced viability was identified for cells in contact with glutaraldehyde vapor-treated fibers and, to a lesser extent, for UV light-treated fibers, whereas MeOH-treated fibers did not affect cell viability. These results elucidated the effects of fiber post-modification on the release kinetics, activity, and biocompatibility of protein drugs and can serve as guidance for rational development of nanomedicines for safe and effective therapeutic delivery of natural proteins.

Delivery of Therapeutic Proteins Using Electrospun Fibers-Recent Developments and Current Challenges.

Proteins play a vital role within the human body by regulating various functions and even serving as structural constituent of many body parts. In this context, protein-based therapeutics have attracted a lot of attention in the last few decades as potential treatment of different diseases. Due to the steadily increasing interest in protein-based therapeutics, different dosage forms were investigated for delivering such complex macromolecules to the human body. Here, electrospun fibers hold a great potential for embedding proteins without structural damage and for controlled release of the protein for therapeutic applications. This review provides a comprehensive overview of the current state of protein-based carrier systems using electrospun fibers, with special emphasis on discussing their potential and key challenges in developing such therapeutic strategies, along with a prospective view of anticipated future directions.

Molecular epidemiology of COVID-19 in Oman: A molecular and surveillance study for the early transmission of COVID-19 in the country.

BACKGROUND: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been proven to be lethal to human health, which affects almost every corner of the world. The objectives of this study were to add context to the global data and international genomic consortiums, and to give insight into the efficiency of the contact tracing system in Oman. METHODS: We combined epidemiological data and whole-genome sequence data from 94 samples of SARS-CoV-2 in Oman to understand the origins, genetic variation, and transmissibility. The whole-genome size of sequence data was obtained through a customized SARS-COV-2 research panel. Amplifier methods ranged from 26 Kbp to 30 Kbp and were submitted to GISAID. FINDINGS: The study found that P323L (94.7%) is the most common mutation, followed by D614G (92.6%) Spike protein mutation. A unique mutation, I280V, was first reported in Oman and was associated with a rare lineage, B.1.113 (10.6%). In addition, the study revealed a good agreement between genetic and epidemiological data. INTERPRETATION: Oman's robust surveillance system was very efficient in guiding the outbreak investigation processes in the country, the study illustrates the future importance of molecular epidemiology in leading the national response to outbreaks and pandemics.

Seroprevalence of SARS-CoV-2 antibodies in the general population of Oman: results from four successive nationwide sero-epidemiological surveys.

OBJECTIVE: To assess the seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in Oman and longitudinal changes in antibody levels over time within the first 11 months of the coronavirus disease 2019 (COVID-19) pandemic. METHODS: This nationwide cross-sectional study was conducted as a four-cycle serosurvey using a multi-stage stratified sampling method from July to November 2020. A questionnaire was used and included demographics, history of acute respiratory infection and list of symptoms, COVID-19 contact, previous diagnosis or admission, travel history and risk factors. RESULTS: In total, 17,457 participants were surveyed. Thirty percent were female and 66.3% were Omani. There was a significant increase in seroprevalence throughout the study cycles, from 5.5% (4.8-6.2%) in Cycle 1 to 22% (19.6-24.6%) in Cycle 4. There was no difference in seroprevalence between genders, but significant differences were found between age groups. There was a transition of seroprevalence from being higher in non-Omanis than Omanis in Cycle 1 [9.1% (7.6-10.9%) vs 3.2% (2.6-3.9%)] to being higher in Omanis than non-Omanis in Cycle 4 [24.3% (21.0-27.9%) vs 16.8% (14.9-18.9%)]. There was remarkable variation in the seroprevalence of SARS-CoV-2 according to governorate. Close contacts of people with COVID-19 had a 96% higher risk of having the disease [adjusted odds ratio (AOR) 1.96, 95% confidence intervals (CI) 1.64-2.34]. Labourers had 58% higher risk of infection compared with office workers (AOR 1.58, 95% CI 1.04-2.35). CONCLUSION: This study showed a wide variation in the spread of SARS-CoV-2 across governorates in Oman, with higher estimated seroprevalence in migrants in the first two cycles. Prevalence estimates remain low and are insufficient to provide herd immunity.

Three-dimensional hierarchical cultivation of human skin cells on bio-adaptive hybrid fibers.

The human skin comprises a complex multi-scale layered structure with hierarchical organization of different cells within the extracellular matrix (ECM). This supportive fiber-reinforced structure provides a dynamically changing microenvironment with specific topographical, mechanical and biochemical cell recognition sites to facilitate cell attachment and proliferation. Current advances in developing artificial matrices for cultivation of human cells concentrate on surface functionalizing of biocompatible materials with different biomolecules like growth factors to enhance cell attachment. However, an often neglected aspect for efficient modulation of cell-matrix interactions is posed by the mechanical characteristics of such artificial matrices. To address this issue, we fabricated biocompatible hybrid fibers simulating the complex biomechanical characteristics of native ECM in human skin. Subsequently, we analyzed interactions of such fibers with human skin cells focusing on the identification of key fiber characteristics for optimized cell-matrix interactions. We successfully identified the mediating effect of bio-adaptive elasto-plastic stiffness paired with hydrophilic surface properties as key factors for cell attachment and proliferation, thus elucidating the synergistic role of these parameters to induce cellular responses. Co-cultivation of fibroblasts and keratinocytes on such fiber mats representing the specific cells in dermis and epidermis resulted in a hierarchical organization of dermal and epidermal tissue layers. In addition, terminal differentiation of keratinocytes at the air interface was observed. These findings provide valuable new insights into cell behaviour in three-dimensional structures and cell-material interactions which can be used for rational development of bio-inspired functional materials for advanced biomedical applications.

Overcoming drug crystallization in electrospun fibers--Elucidating key parameters and developing strategies for drug delivery.

For the development of novel therapeutics, uncontrolled crystallization of drugs within delivery systems represents a major challenge. Especially for thin and flexible polymeric systems such as oral films or dermal wound dressings, the formation and growth of drug crystals can significantly affect drug distribution and release kinetics as well as physical storage stability. In this context, electrospinning was introduced as a fabrication technique with the potential to encapsulate drugs within ultrafine fibers by rapid solvent evaporation overcoming drug crystallization during fabrication and storage. However, these effects could so far only be shown for specific drug-polymer combinations and an in-depth understanding of the underlying processes of drug-loaded fiber formation and influencing key parameters is still missing. In this study, we systematically investigated crystal formation of caffeine as a model drug in electrospun fibers comparing different polymers. The solvent polarity was found to have a major impact on the drug crystal formation, whereas only a minor effect was attributed to the electrospinning process parameters. Based on an in-depth understanding of the underlying processes determining drug crystallization processes in electrospun fibers, key parameters could be identified which allow for the rational development of drug-loaded electrospun fibers overcoming drug crystallization.

The epidemiology and outcomes of infective endocarditis in a tertiary care hospital in Oman.

OBJECTIVES: We undertook this study to describe the epidemiological and clinical features of infective endocarditis (IE) and to study the complications and management of IE in a tertiary care hospital in Oman. METHODS: This is a retrospective study of 58 adult patients (>13 years of age) admitted to the Royal Hospital with IE from June 2006 to June 2011. RESULTS: Of the 58 patients, 40 (69%) were males, and 18 (31%) were females (ratio 2.2). The median age was 43.6 years (range: 14-85). Forty-eight cases (82.7%) had native valves, nine patients (15.6%) had prosthetic valves, and one case (1.7%) had a pacemaker. The most commonly involved valves were mitral (33, 56.9%) and aortic (23, 39.7%). The blood cultures were positive in 47 (81%) patients, and the most commonly isolated organisms were Streptococci spp., which were found in 20 (34.5%) patients, and Staphylococci spp., which were found in 19 (32.8%) patients. The complication rate was 21%. A total of 15 (25.9%) patients underwent surgical intervention, and the in-hospital mortality rate was 27.6%. CONCLUSIONS: Native-valve IE is the predominant type of endocarditis and is more of an acute disease. The prevalence of Staphylococci spp. IE is similar to that of Streptococci spp. IE, and its associated mortality remains high.

Measuring the stratum corneum reservoir: desorption kinetics from keratin.

High keratin binding and slow desorption kinetics are assumed to be responsible for the formation of the stratum corneum (SC) reservoir. We measured equilibrium binding coefficients (K(b)) and desorption rate constants (k(off)) with bovine hoof/horn keratin and six solutes with similar molecular weight (180-288 Da) and varying lipophilicities [expressed as octanol-water distribution coefficient, i.e., a partition coefficient corrected for pH (log K(pH))-0.13 to 3.8]. Two ionizable solutes within this set were tested at different pH values as degree of ionization and lipophilicity were expected to influence equilibrium binding and desorption kinetics. The unbound fraction at equilibrium varied between 18% and 93%. All solutes exhibited linear binding isotherms within the investigated concentration range. Equilibrium binding and the rate of desorption are both functions of solute lipophilicity [log K(b) = 1.23 + 0.32 log K(pH); log k(off) = 1/(25.75 + 8.35 K(pH) (0.34))]. Our results prove that slow desorption from keratin may be a major contributor to the SC reservoir. Also, they prove that reservoir formation is relevant for lipophilic solutes independent of drug class, thus allowing new options for topical pharmacotherapy.

An audit of inpatient management of community-acquired pneumonia in Oman: a comparison with regional clinical guidelines.

OBJECTIVE: Community-acquired pneumonia (CAP) is a major cause of morbidity and mortality worldwide. Herein, we present the findings from an audit of CAP management at a tertiary hospital in Oman. The main objective was to evaluate the quality of care given to patients and compare it with the standards in the Gulf Cooperation Council (GCC) CAP guidelines. METHODS: A retrospective case study of all patients admitted with CAP from June 2006 to September 2008 examined the adherence to standards for the diagnosis, investigation, and management of CAP, including the documentation of illness severity. RESULTS: The case notes of 342 patients were reviewed. Of these, 170 patients were excluded from the study, and 172 patients met the diagnostic criteria for inclusion. A CURB-65 severity score was documented for only 4 (2.3%) patients, and a smoking history was documented for 56 (32.6%) patients. Although 17 different antibiotic regimens were used, 115 (67%) patients received co-amoxiclav and clarithromycin, which is the standard of care. Additionally, 139 (81%) patients received their first dose of antibiotics within four hours of hospital admission. There was no documentation of offering influenza or pneumococcal vaccine to high risk patients. CONCLUSION: The clinical coding of CAP diagnosis was poor. There was very poor adherence to the CAP severity assessment and the provision of preventive measures upon hospital discharge. The development and implementation of a local hospital-based integrated care pathway may lead to more successful implementation of the guidelines.