Intracorneal Amphotericin B Injection in a Case of Indolent Candidal Keratitis

Collagen-binding peptides for the enhanced imaging, lubrication and regeneration of osteoarthritic articular cartilage

Treatments for osteoarthritis would benefit from the enhanced visualization of injured articular cartilage and from the targeted delivery of disease-modifying drugs to it. Here, by using ex vivo human osteoarthritic cartilage and live rats and minipigs with induced osteoarthritis, we report the application of collagen-binding peptides, identified via phage display, that are home to osteoarthritic cartilage and that can be detected via magnetic resonance imaging when conjugated with a superparamagnetic iron oxide. Compared with the use of peptides with a scrambled sequence, hyaluronic acid conjugated with the collagen-binding peptides displayed enhanced retention in osteoarthritic cartilage and better lubricated human osteoarthritic tissue ex vivo. Mesenchymal stromal cells encapsulated in the modified hyaluronic acid and injected intra-articularly in rats showed enhanced homing to osteoarthritic tissue and improved its regeneration. Molecular docking revealed WXPXW as the consensus motif that binds to the α1 chain of collagen type XII. Peptides that specifically bind to osteoarthritic tissue may aid the diagnosis and treatment of osteoarthritic joints.

Recent Perspectives in the Management of Fungal Keratitis

Mycotic keratitis is common in warm, humid regions with a varying profile of pathogenic fungi according to geographical origin, socioeconomic status, and climatic condition. Clinical diagnosis can be challenging in difficult cases and those refractory to treatment. Fungal hyphae on microscopic examination and culture isolation have been the gold standard in the laboratory diagnosis of fungal keratitis. A culture isolate of the aetiological fungus is essential to perform antifungal susceptibility testing. As the culture isolation of fungi is time-consuming, causing delays in the initiation of treatment, newer investigative modalities such as in vivo confocal microscopy and molecular diagnostic methods have recently gained popularity. Molecular diagnostic techniques now help to obtain a rapid diagnosis of fungal keratitis. Genomic approaches are based on detecting amplicons of ribosomal RNA genes, with internal transcribed spacers being increasingly adopted. Metagenomic deep sequencing allows for rapid and accurate diagnosis without the need to wait for the fungus to grow. This is also helpful in identifying new emerging strains of fungi causing mycotic keratitis. A custom-tear proteomic approach will probably play an important diagnostic role in future in the management of mycotic keratitis. Positive repeat cultures are being suggested as an important gauge indicative of a poor prognosis. Positive repeat fungal cultures help to modify a treatment regimen by increasing its frequency, providing the addition of another topical and oral antifungal agent along with close follow-up for perforation and identifying need for early therapeutic keratoplasty. The role of collagen crosslinking in the treatment of fungal keratitis is not convincingly established. Rapid detection by multiplex PCR and antifungal susceptibility testing of the pathogenic fungi, adopted into a routine management protocol of fungal keratitis, will help to improve treatment outcome. Early therapy is essential in minimizing damage to the corneal tissue, thereby providing a better outcome. The role of conventional therapy with polyenes, systemic and targeted therapy of antifungal agents, newer azoles and echinocandins in fungal keratitis has been widely studied in recent times. Combination therapy can be more efficacious in comparison to monotherapy. Given the diversity of fungal aetiology, the emergence of new corneal pathogenic fungi with varying drug susceptibilities, increasing the drug resistance to antifungal agents in some genera and species, it is perhaps time to adopt recent molecular methods for precise identification and incorporate antifungal susceptibility testing as a routine.