Chitosan-sodium percarbonate-based hydrogels with sustained oxygen release potential stimulated angiogenesis and accelerated wound healing.

The prolonged hypoxic conditions hinder chronic wounds from healing and lead to severe conditions such as delayed re-epithelialization and enhanced risk of infection. Multifunctional wound dressings are highly required to address the challenges of chronic wounds. Herein, we report polyurethane-coated sodium per carbonate-loaded chitosan hydrogel (CSPUO2 ) as a multifunctional dressing. The hydrogels (Control, CSPU, and CSPUO2 ) were prepared by freeze gelation method and the developed hydrogels showed high porosity, good absorption capacity, and adequate biodegradability. The release of oxygen from the CSPUO2 hydrogel was confirmed by the increase in pH and a sustained oxygen release was observed over the period of 21 days, due to polyurethane (CSPU) coating. The CSPUO2 hydrogel exhibited around 2-fold increased angiogenic potential in CAM assay when compared with Control and CSPU dressing. CSPUO2 also showed good level of antibacterial efficacy against E. coli and S. aureus. In a full-thickness rat wound model, CSPUO2 hydrogel considerably accelerated wound healing with exceptional re-epithelialization granulation tissue formation less inflammatory cells and improved skin architecture highlighting the tremendous therapeutic potential of this hydrogel when compared with control and CSPU to treat chronic diabetic and burn wounds.

Next-generation whole exome sequencing to delineate the genetic basis of primary congenital glaucoma.

To delineate the genetic bases of primary congenital glaucoma (PCG), we ascertained a large cohort consisting of 48 consanguineous families. Of these, we previously reported 26 families with mutations in CYP1B1 and six families with LTBP2, whereas the genetic bases responsible for PCG in 16 families remained elusive. We employed next-generation whole exome sequencing to delineate the genetic basis of PCG in four of these 16 familial cases. Exclusion of linkage to reported PCG loci was established followed by next-generation whole exome sequencing, which was performed on 10 affected individuals manifesting cardinal systems of PCG belonging to four unresolved families along with four control samples consisting of genomic DNAs of individuals harboring mutations in CYP1B1 and LTBP2. The analyses of sequencing datasets failed to identify potential causal alleles in the 10 exomes whereas c.1169G > A (p. Arg390His) in CYP1B1 and c.3427delC (p.Gln1143Argfs*35) in LTBP2 were identified in the control samples. Taken together, next-generation whole exome sequencing failed to delineate the genetic basis of PCG in familial cases excluded from mutations in CYP1B1 and LTBP2. These data strengthen the notion that compound heterozygous coding variants or non-coding variants might contribute to PCG.

Design and development of thyroxine/heparin releasing affordable cotton dressings to treat chronic wounds.

This research on a thyroxine/heparin-based cotton wound dressing tests angiogenic and wound healing ability of thyroxine/heparin in a chick chorionic allantoic membrane bioassay and in skin wounds in healthy rats. Commercially available cotton dressings were simply loaded with thyroxine/heparin solutions and coated with wax. Prior to undertaking the animal study, we assessed in vitro release of thyroxine/heparin from coated and uncoated cotton dressings. Both showed more than 85% release of drug over 14 days, though the lesser release was observed in wax-coated thyroxine/heparin dressing as compared to uncoated thyroxine/heparin dressing. Testing of angiogenesis through CAM assay proved good angiogenic potential of heparin and thyroxin, but the thyroxine found more angiogenic than heparin. In animal study, full-thickness skin wounds of 20 mm diameter showed good healing in both heparin and thyroxine-treated groups. But the most striking result was seen in the thyroxine-treated group where thyroxine showed significant difference with heparin-treated group and completely healed the wounds in 23 days. Thus, the study suggest that thyroxine possesses greater angiogenic and wound healing potential than heparin, and the use of thyroxine/heparin-loaded wax-coated cotton dressing could be a cost-effective option for the management of chronic wounds.

Developing sulfur-doped titanium oxide nanoparticles loaded chitosan/cellulose-based proangiogenic dressings for chronic ulcer and burn wounds healing.

Development of biomaterials supporting angiogenesis are highly desired in medical applications. In current work, chitosan and cellulose were cross-linked by using triethyl orthoformate and loaded with sulfur-doped titanium oxide nanoparticles. A readily available and inexpensive titanium oxide was added as a potential proangiogenic agent based on our group findings and other reports on metal oxide nanoparticles activity to stimulate angiogenesis. A simple freeze gelation method led to the development of flexible, foldable, and porous membranes. To investigate the chemical characteristics of the synthesized membranes, Fourier-transform infrared spectroscopy was used. Scanning electron microscopy equipped with energy-dispersive X-ray microanalysis was employed for surface morphological investigations. The cross-linked membranes showed higher degree of swelling capacity compared to the same material with titania-loaded nanoparticles in vitro. The synthesized materials showed higher degree of degradation in H2 O2 as compared to phosphate-buffered saline and lysozyme. Chorioallantoic membrane assay was done to investigate the angiogenic potential. Titanium oxide nanoparticles loaded membranes (CLHTS-5 wt%) exhibited the best degree of angiogenesis in comparison to the other tested materials. In CLHTS-5 wt% experimental group, a good level of attachment and ingrowth of several blood vessels was observed. Interestingly, the same tested group (CLHTS-5 wt%) had shown the increasing trend of cellular metabolic rate of the seeded cells from Day 0 to Day 7 in vitro. These findings were further confirmed by the decline in lactate dehydrogenase enzyme release which was monitored until 72 h, indicating the promising ability of this biomaterial in wound healing applications.

Development of NSAID-loaded nano-composite scaffolds for skin tissue engineering applications.

Scar free healing together with pain management is one of the major considerations in full thickness wound healing. Extensive wounds take longer to heal without any clinical intervention and, hence, need natural or artificial extracellular matrix support for quick skin regeneration. To address these issues, medicated 3D porous biomimetic scaffolds were developed with a unique combination of biopolymers, that is, chitosan, sodium alginate, and elastin, supplemented with a non-steroidal anti-inflammatory drug (NSAID). Scaffolds were physically characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), swelling ratio analysis, and degradation studies. Findings of the performed analyses proved that these skin substitutes suitable for skin tissue engineering applications attributable to their nano-microporous structures (pore size in range of 0.085-256 µm) allowing cell infiltration and high-water absorption capacity for management of wound exudates. Optimal dose of the loaded ibuprofen was estimated by evaluating effect of variable concentrations of ibuprofen (control, ILM-10, ILM-15, and ILM-20) on adipose tissue-derived mesenchymal stem cells (ASCs) proliferation rate. Out of all experimental groups, ILM-20 constructs were found to accelerate the proliferation rate of seeded ASCs confirming their non-cytotoxic characteristics as well potential to be used for translational scaffold-based therapies.

Oxygen Generating Polymeric Nano Fibers That Stimulate Angiogenesis and Show Efficient Wound Healing in a Diabetic Wound Model.

INTRODUCTION: Diabetic wounds are challenging to treat due to a wide range of pathophysiological changes. Hypoxia is one of the predominant contributing factors of poor vascularization and chronicity in diabetic wounds. This study was designed to develop polycaprolactone (PCL)-based oxygen-releasing electrospun wound dressings and evaluate their efficacy for improved full thickness wound healing in diabetic rats. METHODS: PCL-based oxygen releasing wound dressings were made using electrospinning technology. The developed dressings were characterized in terms of physical as well as biological properties both in vitro and in vivo. E-spun nanofibrous dressings were physically characterized with scanning electron microscopy, Fourier-transform infrared spectroscopy, and Energy-dispersive X-ray spectroscopy. To study the likely impact of the fabricated wound dressings in hypoxic conditions, HIF-1α expression analysis was carried out both at gene and protein levels. Wound dressings were further evaluated for their healing potential for extensive wounds in diabetic rat models. RESULTS: The experimental results showed that the developed dressings were capable of continuously generating oxygen for up to 10 days. Cell studies further confirmed pronounced expression of HIF-1α at gene and protein levels in cells seeded on PCL-sodium percarbonate (SPC) and PCL scaffolds compared with the cells cultured on a tissue culture plate. Chorioallantoic membrane assay revealed the supportive role of oxygen releasing dressings on angiogenesis compared to the control group. Histological assessment of the regenerated skin tissues proved that full thickness wounds covered with SPC loaded PCL dressings had a comparatively better vascularized and compact extracellular matrix with completely covered thick epithelium. DISCUSSION: The developed oxygen generating polymeric nanofibrous wound dressings could potentially be used as an envisioned approach for the efficient recovery of chronic diabetic wounds.

Thyroxine impregnated chitosan-based dressings stimulate angiogenesis and support fast wounds healing in rats: Potential clinical candidates.

This research paper demonstrates efficacy of chitosan and thyroxine loaded chitosan (CS) dressings for their angiogenic and wound healing potential. The dressings were prepared by freeze gelation method. Thyroxine was loaded by physical adsorption into chitosan membranes. The porosity was analyzed by scanning electron microscopy (SEM) and chemical structures were investigated by Fourier transform infra-red spectroscopy (FTIR). Cell culture studies showed materials were non-toxic and chorioallantoic membranes assay (CAM) confirmed that the thyroxine loaded chitosan stimulated angiogenesis much higher than simple chitosan dressings. In addition, thyroxine loaded dressings showed excellent wound healing potential when tested on full thickness rats wounds. A good epithelialization was obtained along with robust wound closure. Overall, as compared to chitosan, thyroxine containing membranes showed high level of angiogenesis and fast wound healing.