Chitosan-based biocompatible dressing for treatment of recalcitrant lesions of cutaneous leishmaniasis: A pilot clinical study

Nanomaterial-Based Drug Delivery Systems for Ischemic Stroke

Ischemic stroke is a leading cause of death and disability in the world. At present, reperfusion therapy and neuroprotective therapy, as guidelines for identifying effective and adjuvant treatment methods, are limited by treatment time windows, drug bioavailability, and side effects. Nanomaterial-based drug delivery systems have the characteristics of extending half-life, increasing bioavailability, targeting drug delivery, controllable drug release, and low toxicity, thus being used in the treatment of ischemic stroke to increase the therapeutic effects of drugs. Therefore, this review provides a comprehensive overview of nanomaterial-based drug delivery systems from nanocarriers, targeting ligands and stimulus factors of drug release, aiming to find the best combination of nanomaterial-based drug delivery systems for ischemic stroke. Finally, future research areas on nanomaterial-based drug delivery systems in ischemic stroke and the implications of the current knowledge for the development of novel treatment for ischemic stroke were identified.

Efficacy and safety of chitosan-based bio-compatible dressing versus Nano-silver (Acticoat) dressing in treatment of recalcitrant diabetic wounds: A randomized clinical trial

BACKGROUND

Chitosan has a biocompatible, biodegradable, and nontoxic nature. The effectiveness of Nano-chitosan films in the field of wound healing has been confirmed previously.

AIMS

To compare the clinical efficacy and safety of two dressings (chitosan and Nano-silver dressings) in the treatment of refractory diabetic wounds.

METHODS

A total of 25 eligible patients with chronic diabetic wound were included and randomly assigned to receive chitosan (13 patients) or nanosilver (12 cases) dressing. The dressings were applied on the wounds based on their protocols and patients were visited and examined by an experienced dermatologist every week. The clinical assessments and healing rates were recorded using diabetic-foot-infection (DFI) score at the 2^nd , 4^th ,and6^th weeks during treatment. The study endpoint, safety and tolerability profile were also documented.

RESULTS

The patterns of change in total 10-item-DFI wound scores didn't differ significantly over time between the two groups. In both groups, the total 10-item-DFI wound score reduced continuously through the course of study. The mean percentage reduction of this score from baseline was 78.1% and 74.1% in the chitosan and nanosilver dressing groups, respectively. Both dressings were well tolerated and there were no adverse events.

LIMITATIONS

The relatively small sample size in both groups was the main limitation of the study.

CONCLUSIONS

Our findings confirmed that chitosan may be safely and effectively used for the treatment of diabetic wounds just like the nanosilver (acticoat) dressing. Further studies are recommended with more volunteers and a longer follow up period. This article is protected by copyright. All rights reserved.

Nanomedicine in leishmaniasis: A promising tool for diagnosis, treatment and prevention of disease - An update overview

Leishmaniasis is a neglected tropical disease that has a wide spectrum of clinical manifestations, ranging from visceral to cutaneous, with millions of new cases and thousands of deaths notified every year. The severity of the disease and its various clinical forms are determined by the species of the causative agent, Leishmania, as well as the host's immune response. Major challenges still exist in the diagnosis and treatment of leishmaniasis, and there is no vaccine available to prevent this disease in humans. Nanotechnology has emerged as a promising tool in a variety of fields. In this review, we highlight the main and most recent advances in nanomedicine to improve the diagnosis and treatment, as well as for the development of vaccines, for leishmaniasis. Nanomaterials are nanometric in size and can be produced by a variety of materials, including lipids, polymers, ceramics, and metals, with varying structures and morphologies. Nanotechnology can be used as biosensors to detect antibodies or antigens, thus improving the sensitivity and specificity of such immunological and molecular diagnostic tests. While in treatment, nanomaterials can act as drug carriers or, be used directly, to reduce any toxic effects of drug compounds to the host and to be more selective towards the parasite. Furthermore, preclinical studies show that different nanomaterials can carry different Leishmania antigens, or even act as adjuvants to improve a Th1 immune response in an attempt to produce an effective vaccine.

Emerging treatment strategies in wound care

Wound healing is a complex process in tissue regeneration through which the body responds to the dissipated cells as a result of any kind of severe injury. Diabetic and non-healing wounds are considered an unmet clinical need. Currently, different strategic approaches are widely used in the treatment of acute and chronic wounds which include, but are not limited to, tissue transplantation, cell therapy and wound dressings, and the use of an instrument. A large number of literatures have been published on this topic; however, the most effective clinical treatment remains a challenge. The wound dressing involves the use of a scaffold, usually using biomaterials for the delivery of medication, autologous stem cells, or growth factors from the blood. Antibacterial and anti-inflammatory drugs are also used to stop the infection as well as accelerate wound healing. With an increase in the ageing population leading to diabetes and associated cutaneous wounds, there is a great need to improve the current treatment strategies. This research critically reviews the current advancement in the therapeutic and clinical approaches for wound healing and tissue regeneration. The results of recent clinical trials suggest that the use of modern dressings and skin substitutes is the easiest, most accessible, and most cost-effective way to treat chronic wounds with advances in materials science such as graphene as 3D scaffold and biomolecules hold significant promise. The annual market value for successful wound treatment exceeds over $50 billion US dollars, and this will encourage industries as well as academics to investigate the application of emerging smart materials for modern dressings and skin substitutes for wound therapy.

The use of chitosan as a skin-regeneration agent in burns injuries: A review

Chitosan is an amino-polysaccharide, traditionally obtained by the partial deacetylation of chitin from exoskeletons of crustaceans. Properties such as biocompatibility, hemostasis, and the ability to absorb physiological fluids are attributed to this biopolymer. Chitosan’s biological properties are regulated by its origin, polymerization degree, and molecular weight. In addition, it possesses antibacterial and antifungal activities. It also has been used to prepare films, hydrogels, coatings, nanofibers, and absorbent sponges, all utilized for the healing of skin wounds. In in vivo studies with second-degree burns, healing has been achieved in at least 80% of the cases between the ninth and twelfth day of treatment with chitosan coatings. The crucial steps in the treatment of severe burns are the early excision of damaged tissue and adequate coverage to minimize the risk of infection. So far, partial-thickness autografting is considered the gold standard for the treatment of full-thickness burns. However, the limitations of donor sites have led to the development of skin substitutes. Therefore, the need for an appropriate dermal equivalent that functions as a regeneration template for the growth and deposition of new skin tissue has been recognized. This review describes the properties of chitosan that validate its potential in the treatment of skin burns.

Engineering Polysaccharides for Tissue Repair and Regeneration

The success of repair or regeneration depends greatly on the architecture of 3D scaffolds that finely mimic natural extracellular matrix to support cell growth and assembly. Polysaccharides have excellent biocompatibility with intrinsic biological cues and they have been extensively investigated as scaffolds for tissue engineering and regenerative medicine (TERM). The physical and biochemical structures of natural polysaccharides, however, can barely meet all the requirements of tissue-engineered scaffolds. To take advantage of their inherent properties, many innovative approaches including chemical, physical, or joint modifications have been employed to improve their properties. Recent advancement in molecular and material building technology facilitates the fabrication of advanced 3D structures with desirable properties. This review focuses on the latest progress of polysaccharide-based scaffolds for TERM, especially those that construct advanced architectures for tissue regeneration.

Chitosan Contribution to Therapeutic and Vaccinal Approaches for the Control of Leishmaniasis

The control of leishmaniases, a complex parasitic disease caused by the protozoan parasite Leishmania, requires continuous innovation at the therapeutic and vaccination levels. Chitosan is a biocompatible polymer administrable via different routes and possessing numerous qualities to be used in the antileishmanial strategies. This review presents recent progress in chitosan research for antileishmanial applications. First data on the mechanism of action of chitosan revealed an optimal in vitro intrinsic activity at acidic pH, high-molecular-weight chitosan being the most efficient form, with an uptake by pinocytosis and an accumulation in the parasitophorous vacuole of Leishmania-infected macrophages. In addition, the immunomodulatory effect of chitosan is an added value both for the treatment of leishmaniasis and the development of innovative vaccines. The advances in chitosan chemistry allows pharmacomodulation on amine groups opening various opportunities for new polymers of different size, and physico-chemical properties adapted to the chosen routes of administration. Different formulations have been studied in experimental leishmaniasis models to cure visceral and cutaneous leishmaniasis, and chitosan can act as a booster through drug combinations with classical drugs, such as amphotericin B. The various architectural possibilities given by chitosan chemistry and pharmaceutical technology pave the way for promising further developments.

Nanoparticles: New agents toward treatment of leishmaniasis

Leishmaniasis is a widespread disease that causes 20,000 to 30,000 deaths annually, making it a major health problem in endemic areas. Because of low-performance medications, drug delivery poses a great challenge for better treatment of leishmaniasis. The present study's purpose was to review the application of nanoparticles as a new method in leishmaniasis treatment. To identify all relevant literature, we searched Web of Sciences, Scopus, PubMed, NCBI, Scielo, and Google Scholar, and profiled studies published between 1986 and 2019. In the present study, we tried to identify different research efforts in different conditions that examined the influence of various nanoparticles on different forms of leishmaniasis. In this way, we could compare their results and obtain a reliable conclusion from the most recent studies on this subject. Our review's results indicate that incorporating nanoparticles with chemical drugs improves the quality, efficiency, and sustainability of drugs and reduces their costs. Finally, considering the use of nanoparticles in the destruction of parasites, their inhibitory effect (making drugs more effective and less harmful), and their utility in making effective vaccines to prevent and fight against parasites, further research on this issue is highly recommended.

Chitosan-based particulate systems for drug and vaccine delivery in the treatment and prevention of neglected tropical diseases

Neglected tropical diseases (NTDs) are a diverse group of infections which are difficult to prevent or control, affecting impoverished communities that are unique to tropical or subtropical regions. In spite of the low number of drugs that are currently used for the treatment of these diseases, progress on new drug discovery and development for NTDs is still very limited. Therefore, strategies on the development of new delivery systems for current drugs have been the main focus of formulators to provide improved efficacy and safety. In recent years, particulate delivery systems at micro- and nanosize, including polymeric micro- and nanoparticles, liposomes, solid lipid nanoparticles, metallic nanoparticles, and nanoemulsions, have been widely investigated in the treatment and control of NTDs. Among these polymers used for the preparation of such systems is chitosan, which is a marine biopolymer obtained from the shells of crustaceans. Chitosan has been investigated as a delivery system due to the versatility of its physicochemical properties as well as bioadhesive and penetration-enhancing properties. Furthermore, chitosan can be also used to improve treatment due to its bioactive properties such as antimicrobial, tissue regeneration, etc. In this review, after giving a brief introduction to neglected diseases and particulate systems developed for the treatment and control of NTDs, the chitosan-based systems will be described in more detail and the recent studies on these systems will be reviewed. Graphical abstract.