Promising applications of D-amino acids in periprosthetic joint infection

Due to the rise in our aging population,a disproportionate demand for total joint arthroplasty(TJA)in the elderly is forecast.Periprosthetic joint infection(PJI)represents one of the most challenging complications that can occur following TJA,and as the number of primary and revision TJAs continues to rise,an increasing PJI burden is projected.Despite advances in operating room sterility,antiseptic protocols,and surgical techniques,approaches to prevent and treat PJI remain difficult,primarily due to the formation of microbial biofilms.This difficulty motivates researchers to continue searching for an effective antimicrobial strategy.The dextrorotatory-isoforms of amino acids(D-AAs)are essential components of peptidoglycan within the bacterial cell wall,providing strength and structural integrity in a diverse range of species.Among many tasks,D-AAs regulate cell morphology,spore germination,and bacterial survival,evasion,subversion,and adhesion in the host immune system.When administered exogenously,accumulating data have demonstrated that D-AAs play a pivotal role against bacterial adhesion to abiotic surfaces and subsequent biofilm formation;furthermore,D-AAs have substantial efficacy in promoting biofilm disassembly.This presents D-AAs as promising and novel targets for future therapeutic approaches.Despite their emerging antibacterial efficacy,their role in disrupting PJI biofilm formation,the disassembly of established TJA biofilm,and the host bone tissue response remains largely unexplored.This review aims to examine the role of D-AAs in the context of TJAs.Data to date suggest that D-AA bioengineering may serve as a promising future strategy in the prevention and treatment of PJI.

Changes in interstitial fluid flow,mass transport and the bone cell response in microgravity and normogravity

In recent years,our scientific interest in spaceflight has grown exponentially and resulted in a thriving area of research,with hundreds of astronauts spending months of their time in space.A recent shift toward pursuing territories farther afield,aiming at near-Earth asteroids,the Moon,and Mars combined with the anticipated availability of commercial flights to space in the near future,warrants continued understanding of the human physiological processes and response mechanisms when in this extreme environment.Acute skeletal loss,more severe than any bone loss seen on Earth,has significant implications for deep space exploration,and it remains elusive as to why there is such a magnitude of difference between bone loss on Earth and loss in microgravity.The removal of gravity eliminates a critical primary mechano-stimulus,and when combined with exposure to both galactic and solar cosmic radiation,healthy human tissue function can be negatively affected.An additional effect found in microgravity,and one with limited insight,involves changes in dynamic fluid flow.Fluids provide the most fundamental way to transport chemical and biochemical elements within our bodies and apply an essential mechano-stimulus to cells.Furthermore,the cell cytoplasm is not a simple liquid,and fluid transport phenomena together with viscoelastic deformation of the cytoskeleton play key roles in cell function.In microgravity,flow behavior changes drastically,and the impact on cells within the porous system of bone and the influence of an expanding level of adiposity are not well understood.This review explores the role of interstitial fluid motion and solute transport in porous bone under two different conditions:normogravity and microgravity.