Association Between the Affordable Care Act Medicaid Expansion and Receipt of Cardiac Resynchronization Therapy by Race and Ethnicity

BACKGROUND: Black and Hispanic patients are less likely to receive cardiac resynchronization therapy (CRT) than White patients. Medicaid expansion has been associated with increased access to cardiovascular care among racial and ethnic groups with higher prevalence of underinsurance. It is unknown whether the Medicaid expansion was associated with increased receipt of CRT by race and ethnicity. METHODS AND RESULTS: Using Healthcare Cost and Utilization Project Data State Inpatient Databases from 19 states and Washington, DC, we analyzed 1061 patients from early-adopter states (Medicaid expansion by January 2014) and 745 patients from nonadopter states (no implementation 2013–2014). Estimates of change in census-adjusted rates of CRT with or without defibrillator by race and ethnicity and Medicaid adopter status 1 year before and after January 2014 were conducted using a quasi-Poisson regression model. Following the Medicaid expansion, the rate of CRT did not significantly change among Black individuals from early-adopter states (1.07 [95% CI, 0.78–1.48]) or nonadopter states (0.79 [95% CI, 0.57–1.09]). There were no significant changes in rates of CRT among Hispanic individuals from early-adopter states (0.99 [95% CI, 0.70–1.38]) or nonadopter states (1.01 [95% CI, 0.65–1.57]). There was a 34% increase in CRT rates among White individuals from early-adopter states (1.34 [95% CI, 1.05–1.70]), and no significant change among White individuals from nonadopter states (0.77 [95% CI, 0.59–1.02]). The change in CRT rates among White individuals was associated with the timing of the Medicaid implementation (P=0.003). CONCLUSIONS: Among states participating in Healthcare Cost and Utilization Project Data State Inpatient Databases, implementation of Medicaid expansion was associated with increase in CRT rates among White individuals residing in states that adopted the Medicaid expansion policy. Further work is needed to address disparities in CRT among Black and Hispanic patients. © 2022 The Authors.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Biogenesis of Nanotubular Network in Toxoplasma Parasitophorous Vacuole Induced by Parasite Proteins

The intracellular parasite Toxoplasma gondii develops within a nonfusogenic vacuole containing a network of elongated nanotubules that form connections with the vacuolar membrane. Parasite secretory proteins discharged from dense granules (known as GRA proteins) decorate this intravacuolar network after invasion. Herein, we show using specific gene knockout mutants, that the unique nanotubule conformation of the network is induced by the parasite secretory protein GRA2 and further stabilized by GRA6. The vacuolar compartment generated by GRA2 knockout parasites was dramatically disorganized, and the normally tubular network was replaced by small aggregated material. The defect observed in Δgra2 parasites was evident from the initial stages of network formation when a prominent cluster of multilamellar vesicles forms at a posterior invagination of the parasite. The secretory protein GRA6 failed to localize properly to this posterior organizing center in Δgra2 cells, indicating that this early conformation is essential to proper assembly of the network. Construction of a Δgra6 mutant also led to an altered mature network characterized by small vesicles instead of elongated nanotubules; however, the initial formation of the posterior organizing center was normal. Complementation of the Δgra2 knockout with mutated forms of GRA2 showed that the integrity of both amphipathic alpha-helices of the protein is required for correct formation of the network. The induction of nanotubues by the parasite protein GRA2 may be a conserved feature of amphipathic alpha-helical regions, which have also been implicated in the organization of Golgi nanotubules and endocytic vesicles in mammalian cells

A Dynamin–Cortactin–Arp2/3 Complex Mediates Actin Reorganization in Growth Factor-stimulated Cells

The mechanisms by which mammalian cells remodel the actin cytoskeleton in response to motogenic stimuli are complex and a topic of intense study. Dynamin 2 (Dyn2) is a large GTPase that interacts directly with several actin binding proteins, including cortactin. In this study, we demonstrate that Dyn2 and cortactin function to mediate dynamic remodeling of the actin cytoskeleton in response to stimulation with the motogenic growth factor platelet-derived growth factor. On stimulation, Dyn2 and cortactin coassemble into large, circular structures on the dorsal cell surface. These “waves” promote an active reorganization of actin filaments in the anterior cytoplasm and function to disassemble actin stress fibers. Importantly, inhibition of Dyn2 and cortactin function potently blocked the formation of waves and subsequent actin reorganization. These findings demonstrate that cortactin and Dyn2 function together in a supramolecular complex that assembles in response to growth factor stimulation and mediates the remodeling of actin to facilitate lamellipodial protrusion at the leading edge of migrating cells