Systemic application of bone-targeting peptidoglycan hydrolases as a novel treatment approach for staphylococcal bone infection

IMPORTANCE

The rising prevalence of antimicrobial resistance in S. aureus has rendered treatment of staphylococcal infections increasingly difficult, making the discovery of alternative treatment options a high priority. Peptidoglycan hydrolases, a diverse group of bacteriolytic enzymes, show high promise as such alternatives due to their rapid and specific lysis of bacterial cells, independent of antibiotic resistance profiles. However, using these enzymes for the systemic treatment of local infections, such as osteomyelitis foci, needs improvement, as the therapeutic distributes throughout the whole host, resulting in low concentrations at the actual infection site. In addition, the occurrence of intracellularly persisting bacteria can lead to relapsing infections. Here, we describe an approach using tissue-targeting to increase the local concentration of therapeutic enzymes in the infected bone. The enzymes were modified with a short targeting moiety that mediated accumulation of the therapeutic in osteoblasts and additionally enables targeting of intracellularly surviving bacteria.

Biomaterial strategies for improved intra-articular drug delivery

Osteoarthritis (OA) is a joint degenerative disease that has become one of the leading causes of disability in the world. It is estimated that OA affects 50 million adults in the United States. Currently, there are no FDA-approved treatments that slow OA progression and its treatment is limited to pain management strategies and life style changes. Despite the discovery of several disease-modifying OA drugs (DMOADs) and promising results in preclinical studies, their clinical translation has been significantly limited because of poor intra-articular (IA) bioavailability and challenges in delivering these compounds to tissues of interest within the joint. Here, we review current OA treatments and their effectiveness at reducing joint pain, as well as novel targets for OA treatment and the challenges related to their clinical translation. Moreover, we discuss intra-articular (IA) drug delivery as a promising route of administration, describe its inherent challenges, and review recent advances in biomaterial-based IA drug delivery for OA treatment. Finally, we highlight the potential of tissue targeting in the development of effective IA drug delivery systems.