ABSTRACT
Pre-exposure prophylaxis (PrEP) is pivotal in curbing HIV transmission and is integral to the national plan to end the HIV epidemic in the United States (US). Nonetheless, widespread PrEP adoption faces barriers. Telehealth delivery models for PrEP, or telePrEP, can enhance PrEP access and adherence by providing flexible care remotely. This study presents a systematic review of telePrEP programs in the US, aiming to describe model characteristics and summarize clinical, implementation, and equity outcomes. We reviewed studies published from 2012 to 2023. We included articles that described telePrEP systems in the US and measured PrEP care continuum outcomes (awareness, initiation, uptake, adherence) or acceptability of the intervention by program users. Eight articles describing six distinct telePrEP initiatives met our inclusion criteria. Studies described models implemented in community-based, academic, and commercial settings, with most programs using a direct-to-client telePrEP model. Across studies, clients reported high acceptability of the telePrEP programs, finding them easy to use, convenient, and helpful as a tool for accessing HIV prevention services. No programs were offering injectable PrEP at the time these studies were conducted. Data was limited in measuring PrEP retention rates and the reach of services to underserved populations, including Black and Latinx communities, transgender individuals, and cis-gender women. Findings underscore the potential of telePrEP to bolster the reach of PrEP care and address structural barriers to access. As telehealth models for PrEP care gain prominence, future research should concentrate on refining implementation strategies, enhancing equity outcomes, and expanding services to include injectable PrEP.
ABSTRACT
RPE cells are the most actively phagocytic cells in the human body. In the eye, RPE cells face rod and cone photoreceptor outer segments at all times but contribute to shedding and clearance phagocytosis of distal outer segment tips only once a day. Analysis of RPE phagocytosis in situ has succeeded in identifying key players of the RPE phagocytic mechanism. Phagocytic processes comprise three distinct phases, recognition/binding, internalization, and digestion, each of which is regulated separately by phagocytes. Studies of phagocytosis by RPE cells in culture allow specifically analyzing and manipulating these distinct phases to identify their molecular mechanisms. Here, we compare similarities and differences of primary, immortalized, and stem cell-derived RPE cells in culture to RPE cells in situ with respect to phagocytic function. We discuss in particular potential pitfalls of RPE cell culture phagocytosis assays. Finally, we point out considerations for phagocytosis assay development for future studies.
