Osteopontin (OPN) is abundantly expressed in human calcified arteries. To examine the role of OPN in vascular calcification, OPN mutant mice were crossed with matrix Gla protein (MGP) mutant mice. Mice deficient in MGP alone (MGP−/− OPN+/+) showed calcification of their arteries as early as 2 weeks (wk) after birth (0.33 ± 0.01 mmol/g dry weight), and the expression of OPN in the calcified arteries was greatly up-regulated compared with MGP wild-types. OPN accumulated adjacent to the mineral and colocalized to surrounding cells in the calcified media. Cells synthesizing OPN lacked smooth muscle (SM) lineage markers, SM α-actin and SM22α. However, most of them were not macrophages. Importantly, mice deficient in both MGP and OPN had twice as much arterial calcification as MGP−/− OPN+/+ at 2 wk, and over 3 times as much at 4 wk, suggesting an inhibitory effect of OPN in vascular calcification. Moreover, these mice died significantly earlier (4.4 ± 0.2 wk) than MGP−/− OPN+/+ counterparts (6.6 ± 1.0 wk). The cause of death in these animals was found to be vascular rupture followed by hemorrhage, most likely due to enhanced calcification. These studies are the first to demonstrate a role for OPN as an inducible inhibitor of ectopic calcification in vivo.
Background National guidelines for the provision of HIV pre-exposure prophylaxis (PrEP) to reduce a person’s risk of acquiring HIV were made available in 2014. We created a pharmacist-managed HIV PrEP clinic in a community pharmacy setting at Kelley-Ross Pharmacy in Seattle, WA, USA. Methods: The clinic operates under a collaborative drug therapy agreement based on these guidelines. This allows pharmacists to initiate and manage tenofovir disoproxil fumarate/emtricitabine under the supervision of a physician medical director. Results: Between March 2015 and February 2018, 714 patients were evaluated and 695 (97.3%) initiated PrEP. Five hundred and thirteen (74%) patients began medication the same day as their initial appointment. Of the prescriptions filled in our pharmacy, 90% of patients had a mean proportion of days covered (PDC) greater than 80%, and 98% had a zero-dollar patient responsibility per month, including uninsured individuals. 19% of patients were lost to follow up, with an effective drop-out rate of 25%. Two hundred and seven diagnoses of sexually transmissible infections were made. There were no HIV seroconversions in the service. Conclusion: The pharmacist-managed PrEP clinic proved to be a successful alternative model of PrEP care, with high initiation rates and low drop-out and lost-to-follow-up rates. This may benefit individuals who do not access PrEP in traditional health care settings or where PrEP access is scarce. Financial sustainability of the model was dependent on the ability of pharmacists in the clinic to bill insurance plans for their services in accordance with Washington State legislative changes requiring commercial insurances to recognise pharmacists as providers.
Ectopic calcification is a major cause of bioprosthetic heart valve failure. New therapeutic opportunities are offered by the growing understanding that ectopic calcification is an actively regulated process involving several key gene products. One of these products, osteopontin (OPN), is a glycosylated phosphoprotein previously shown to inhibit apatite crystal formation, induce carbonic anhydrase II, and promote mineral resorption. In this study, OPN-deficient mice (OPN-/-) were utilized as an in vivo model to stimulate the ectopic calcification of glutaraldehyde-fixed bovine pericardium (GFBP) tissue and to examine OPN delivery and structure-function relationships with respect to its anti-calcific activity. Significant calcification of GFBP tissue was obtained within 7 days of subcutaneous implantation in OPN-/- mice. Direct rescue of the calcification phenotype was achieved by the administration of exogenous recombinant rat, histidine-fused OPN (rat His-OPN) to the implant site via soluble injection (up to 72% mitigation achieved) or adsorption onto the implant materials (up to 91% mitigation achieved). Effects were specific, since neither fibronectin nor polyhistidine alone could mitigate calcification of GFBP. The maximum anti-calcific effect was achieved only when rat His-OPN was adequately phosphorylated and contained a functional arginine-glycine-aspartate (RGD) cell adhesive domain. Furthermore, CAII levels in host cells surrounding GFBP were greatest when phosphorylated, RGD-containing rat His-OPN was adsorbed. These data suggest that both physical inhibition, mediated by phosphorylation sites in OPN, as well as the induction of CAII and mineral regression, mediated by the RGD domain, contribute to the unique ability of OPN to mitigate ectopic calcification of bioprosthetic valve tissue.
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