Splenic monocytes drive pathogenic subretinal inflammation in age-related macular degeneration.

Age-related macular degeneration (AMD) is invariably associated with the chronic accumulation of activated mononuclear phagocytes in the subretinal space. The mononuclear phagocytes are composed of microglial cells but also of monocyte-derived cells, which promote photoreceptor degeneration and choroidal neovascularization. Infiltrating blood monocytes can originate directly from bone marrow, but also from a splenic reservoir, where bone marrow monocytes develop into angiotensin II receptor (ATR1)+ splenic monocytes. The involvement of splenic monocytes in neurodegenerative diseases such as AMD is not well understood. Using acute inflammatory and well-phenotyped AMD models, we demonstrate that angiotensin II mobilizes ATR1+ splenic monocytes, which we show are defined by a transcriptional signature using single-cell RNA sequencing and differ functionally from bone marrow monocytes. Splenic monocytes participate in the chorio-retinal infiltration and their inhibition by ATR1 antagonist and splenectomy reduces the subretinal mononuclear phagocyte accumulation and pathological choroidal neovascularization formation. In aged AMD-risk ApoE2-expressing mice, a chronic AMD model, ATR1 antagonist and splenectomy also inhibit the chronic retinal inflammation and associated cone degeneration that characterizes these mice. Our observation of elevated levels of plasma angiotensin II in AMD patients, suggests that similar events take place in clinical disease and argue for the therapeutic potential of ATR1 antagonists to inhibit splenic monocytes for the treatment of blinding AMD.

Targeting CD38 with Daratumumab in Refractory Systemic Lupus Erythematosus.

Daratumumab, a human monoclonal antibody that targets CD38, depletes plasma cells and is approved for the treatment of multiple myeloma. Long-lived plasma cells are implicated in the pathogenesis of systemic lupus erythematosus because they secrete autoantibodies, but they are unresponsive to standard immunosuppression. We describe the use of daratumumab that induced substantial clinical responses in two patients with life-threatening lupus, with the clinical responses sustained by maintenance therapy with belimumab, an antibody to B-cell activating factor. Significant depletion of long-lived plasma cells, reduction of interferon type I activity, and down-regulation of T-cell transcripts associated with chronic inflammation were documented. (Supported by the Deutsche Forschungsgemeinschaft and others.).

Cost-Effectiveness of Medication Therapy Management Program Across Racial and Ethnic Groups Among Medicare Beneficiaries.

OBJECTIVES: Equity and effectiveness of the medication therapy management (MTM) program in Medicare has been a policy focus since its inception. The objective of this study was to evaluate the cost-effectiveness of the Medicare MTM program in improving medication utilization quality across racial and ethnic groups. METHODS: This study analyzed 2017 Medicare data linked to the Area Health Recourses File. A propensity score was used to match MTM enrollees and nonenrollees, and an incremental cost-effectiveness ratio between the 2 groups was calculated. Effectiveness was measured as the proportion of appropriate medication utilization based on medication utilization measures developed by Pharmacy Quality Alliance. Net monetary benefits were compared across racial and ethnic groups at various societal willingness-to-pay (WTP) thresholds. The 95% confidence intervals were obtained by nonparametric bootstrapping. RESULTS: MTM dominated non-MTM among the total sample (N = 699 992), as MTM enrollees had lower healthcare costs ($31 135.89 vs $32 696.69) and higher proportions of appropriate medication utilization (87.47% vs 85.31%) than nonenrollees. MTM enrollees had both lower medication costs ($10 681.21 vs $11 003.08) and medical costs ($20 454.68 vs $21 693.61) compared with nonenrollees. The cost-effectiveness of MTM was higher among Black patients than White patients across the WTP thresholds. For instance, at a WTP of $3006 per percentage point increase in effectiveness, the net monetary benefit for Black patients was greater than White patients by $2334.57 (95% confidence interval $1606.53-$3028.85). CONCLUSIONS: MTM is cost-effective in improving medication utilization quality among Medicare beneficiaries and can potentially reduce disparities between Black and White patients. Expansion of the current MTM program could maximize these benefits.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition).

The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer-reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state-of-the-art handbook for basic and clinical researchers.

Structural and functional distinctions of co-resident microglia and monocyte-derived macrophages after retinal degeneration.

BACKGROUND: Both resident microglia and invading peripheral immune cells can respond to injury and degeneration in the central nervous system. However, after dead and dying neurons have been cleared and homeostasis is re-established, it is unknown whether resident immune cells fully resume normal functions and to what degree the peripheral immune cells take up residence. METHODS: Using flow cytometry, in vivo retinal imaging, immunohistochemistry, and single-cell mRNA sequencing, we assess resident microglia and monocyte-derived macrophages in the retina during and after the loss of photoreceptors in the Arr1-/- mouse model of inducible degeneration. RESULTS: We find that photoreceptor loss results in a small, sustained increase in mononuclear phagocytes and, after degeneration wanes, these cells re-establish a spatial mosaic reminiscent of healthy retinas. Transcriptomic analysis revealed the population remained unusually heterogeneous, with several subpopulations expressing gene patterns consistent with mildly activated phenotypes. Roughly a third of "new resident" cells expressed markers traditionally associated with both microglial and monocytic lineages, making their etiology ambiguous. Using an inducible Cre-based fluorescent lineage tracing paradigm to confirm the origins of new resident immune cells, we found approximately equal numbers of microglia and monocyte-derived macrophages after degeneration had subsided. In vivo retinal imaging and immunohistochemical analysis showed that both subpopulations remained functionally responsive to sites of local damage, though on average the monocyte-derived cells had less morphological complexity, expressed higher levels of MHCII, and had less migratory activity than the native resident population. CONCLUSIONS: Monocytic cells that infiltrate the retina during degeneration differentiate into monocyte-derived macrophages that can remain in the retina long-term. These monocyte-derived macrophages adopt ramified morphologies and microglia-like gene expression. However, they remain distinguishable in morphology and gene expression from resident microglia and appear to differ functionally, showing less responsiveness to subsequent retinal injuries. These findings support the idea that persistent changes in the local immune population that occur in response to cell loss in aging and progressive retinal diseases may include the establishment of subpopulations of bone marrow-derived cells whose ability to respond to subsequent insults wanes over time.

Evaluation of SIGLEC1 in the diagnosis of suspected systemic lupus erythematosus.

OBJECTIVES: To evaluate and compare the diagnostic accuracy of SIGLEC1, a surrogate marker of type I IFN, with established biomarkers in an inception cohort of systemic lupus erythematosus (SLE). METHODS: SIGLEC1 was analysed by flow cytometry in 232 patients referred to our institution with suspected SLE between October 2015 and September 2020. RESULTS: SLE was confirmed in 76 of 232 patients (32.8 %) according to the 2019 EULAR/ACR classification criteria and their SIGLEC1 values were significantly higher compared with patients without SLE (P <0.0001). A sensitivity of 98.7 %, a specificity of 82.1 %, a negative predictive value (NPV) of 99.2 % and a positive predictive value (PPV) of 72.8 % were calculated for SIGLEC1. Adjusted to the highest reported prevalence of SLE, the NPV and PPV were >99.9 % and 0.1 %, respectively. Using receiver operating characteristic (ROC) analysis and DeLong testing, the area under the curve (AUC) for SIGLEC1 (AUC = 0.95) was significantly higher than for ANA (AUC = 0.88, P = 0.031), C3 (AUC = 0.83, P = 0.001) and C4 (AUC = 0.83, P = 0.002) but not for anti-dsDNA antibodies (AUC = 0.90, P = 0.163). CONCLUSION: IFN-I pathway activation is detectable in almost all newly diagnosed SLE patients. Thus, a negative test result for SIGLEC1 is powerful to exclude SLE in suspected cases.

Effects of Medicare comprehensive medication review on racial/ethnic disparities in nonadherence to statin medications among patients with Alzheimer's Disease: an observational analysis.

BACKGROUND: Alzheimer's Disease (AD) is the mostcommon cause of dementia, a neurological disorder characterized by memory loss and judgment impairment. Hyperlipidemia, a commonly co-occurring condition, should be treated to prevent associated complications. Medication adherence may be difficult for individuals with AD due to the complexity of AD management. Comprehensive Medication Reviews (CMRs), a required component of Medicare Part D Medication Therapy Management (MTM), have been shown to improve medication adherence. However, many MTM programs do not target AD. Additionally, racial/ethnic disparities in MTM eligibility have been revealed. Thus, this study examined the effects of CMR receipt on reducing racial/ethnic disparities in the likelihood of nonadherence to hyperlipidemia medications (statins) among the AD population. METHODS: This retrospective study used 2015-2017 Medicare data linked to the Area Health Resources Files. The likelihood of nonadherence to statin medications across racial/ethnic groups was compared between propensity-score-matched CMR recipients and non-recipients in a ratio of 1 to 3. A difference-in-differences method was utilized to determine racial/ethnic disparity patterns using a logistic regression by including interaction terms between dummy variables for CMR receipt and each racial/ethnic minority group (non-Hispanic Whites, or Whites, as reference). RESULTS: The study included 623,400 Medicare beneficiaries. Blacks and Hispanics had higher statin nonadherence than Whites: Compared to Whites, Blacks' nonadherence rate was 4.53% higher among CMR recipients and 7.35% higher among non-recipients; Hispanics' nonadherence rate was 2.69% higher among CMR recipients and 7.38% higher among non-recipients. Differences in racial/ethnic disparities between CMR recipients and non-recipients were significant for each minority group (p < 0.05) except Others. The difference between Whites and Hispanics in the odds of statin nonadherence was 11% lower among CMR recipients compared to non-recipients (OR = 0.89; 95% Confidence Interval = 0.85-0.94 for the interaction term between dummy variables for CMR and Hispanics). Interaction terms between dummy variables for CMR and other racial/ethnic minorities were not significant. CONCLUSIONS: Receiving a CMR was associated with a disparity reduction in nonadherence to statin medications between Hispanics and Whites among patients with AD. Strategies need to be explored to increase the number of MTM programs that target AD and promote CMR completion.

In vivo imaging reveals transient microglia recruitment and functional recovery of photoreceptor signaling after injury.

Microglia respond to damage and microenvironmental changes within the central nervous system by morphologically transforming and migrating to the lesion, but the real-time behavior of populations of these resident immune cells and the neurons they support have seldom been observed simultaneously. Here, we have used in vivo high-resolution optical coherence tomography (OCT) and scanning laser ophthalmoscopy with and without adaptive optics to quantify the 3D distribution and dynamics of microglia in the living retina before and after local damage to photoreceptors. Following photoreceptor injury, microglia migrated both laterally and vertically through the retina over many hours, forming a tight cluster within the area of visible damage that resolved over 2 wk. In vivo OCT optophysiological assessment revealed that the photoreceptors occupying the damaged region lost all light-driven signaling during the period of microglia recruitment. Remarkably, photoreceptors recovered function to near-baseline levels after the microglia had departed the injury locus. These results demonstrate the spatiotemporal dynamics of microglia engagement and restoration of neuronal function during tissue remodeling and highlight the need for mechanistic studies that consider the temporal and structural dynamics of neuron-microglia interactions in vivo.

PRCD is essential for high-fidelity photoreceptor disc formation.

Progressive rod-cone degeneration (PRCD) is a small protein residing in the light-sensitive disc membranes of the photoreceptor outer segment. Until now, the function of PRCD has remained enigmatic despite multiple demonstrations that its mutations cause blindness in humans and dogs. Here, we generated a PRCD knockout mouse and observed a striking defect in disc morphogenesis, whereby newly forming discs do not properly flatten. This leads to the budding of disc-derived vesicles, specifically at the site of disc morphogenesis, which accumulate in the interphotoreceptor matrix. The defect in nascent disc flattening only minimally alters the photoreceptor outer segment architecture beyond the site of new disc formation and does not affect the abundance of outer segment proteins and the photoreceptor's ability to generate responses to light. Interestingly, the retinal pigment epithelium, responsible for normal phagocytosis of shed outer segment material, lacks the capacity to clear the disc-derived vesicles. This deficiency is partially compensated by a unique pattern of microglial migration to the site of disc formation where they actively phagocytize vesicles. However, the microglial response is insufficient to prevent vesicular accumulation and photoreceptors of PRCD knockout mice undergo slow, progressive degeneration. Taken together, these data show that the function of PRCD is to keep evaginating membranes of new discs tightly apposed to each other, which is essential for the high fidelity of photoreceptor disc morphogenesis and photoreceptor survival.

Racial and ethnic disparities associated with the measure for drug-drug interactions among Medicare beneficiaries.

BACKGROUND: Drug-drug interactions (DDIs) cause many preventable hospitalizations and admissions. Efforts have been made to raise DDI awareness and reduce DDI occurrence; for example, Medicare Part D Star Ratings, a health plan quality assessment program, included a DDI measure. Previous research reported racial and ethnic disparities in health services utilization and that racial and ethnic minorities, compared with non-Hispanic whites (whites), may be less likely to be targeted for a similar measure, a Star Ratings adherence measure for diabetes medications. OBJECTIVE: This study aimed to investigate whether any racial and ethnic disparities are associated with the DDI measure in Part D Star Ratings among Medicare populations with diabetes, hypertension, and hyperlipidemia. METHODS: This cross-sectional study analyzed a 2017 Medicare Part D data sample, including 3,960,813 beneficiaries. Because the inclusion in the denominator of the Star Ratings DDI measure was determined by the use of a list of target medications, the likelihood of using a listed target medication was compared between racial and ethnic minorities and whites. Individuals with diabetes, hypertension, and hyperlipidemia were included in the analysis owing to the high prevalence of these conditions. Patient- and community-level characteristics were adjusted by logistic regression. RESULTS: Of the entire study sample, 26.2% used a target medication. Compared with whites, most racial and ethnic minorities were less likely to use a target medication. For example, among individuals with diabetes, blacks, Hispanics, Asians/Pacific Islanders, and others had, respectively, 14% (odds ratio 0.86 [95% CI 0.84-0.88]), 5% (0.95 [0.93-0.98]), 12% (0.88 [0.84-0.92]), and 10% (0.90 [0.87-0.93]) lower odds compared with whites. Findings were similar among hypertension and hyperlipidemia cohorts, except that Hispanics had similar odds of use as whites. CONCLUSION: Most racial and ethnic minorities may have lower likelihood of being targeted for the DDI measure compared with whites. Future studies should examine whether these disparities affect health outcomes and devise new DDI measures for racial and ethnic minorities.

A social media microinfluencer intervention to reduce coronavirus disease 2019 vaccine hesitancy in underserved Tennessee communities: A protocol paper.

BACKGROUND: Central to effective public health policy and practice is the trust between the population served and the governmental body leading health efforts, but that trust has eroded in the years preceding the pandemic. Vaccine hesitancy among adults is also a growing concern across the United States. Recent data suggest that the trustworthiness of information about the coronavirus 2019 (COVID-19) vaccine was a larger concern than the vaccine's adverse effects or risks. OBJECTIVE: This study aims to describe the methods used to create a public health microinfluencer social media vaccine confidence campaign for the COVID-19 vaccine in underserved Tennessee communities. A secondary objective is to describe how the Social-Ecological Model (SEM) and Social Cognitive Theory may address vaccine hesitancy using community pharmacies. METHODS: In late 2020, 50 independent community pharmacies in underserved communities across Tennessee were involved in a public health project with the State of Tennessee Department of Health and the University of Tennessee Health Science Center College of Pharmacy. The project involved a 3-pronged, pharmacy-based COVID-19 vaccination outreach project, including (1) social media messaging (i.e., microinfluencer approach), (2) community partner collaboration, and (3) in-pharmacy promotion. Quantitative and qualitative data will assess the quality and effectiveness of the program. Social media outcomes will also be assessed to measure the impact of the microinfluencer social media training. RESULTS: Project implementation is planned for 6 months (January 2021 to June 2021) after an initial month of planning by the research team (December 2020) and preceding several months of assessment (July 2021 and beyond). CONCLUSIONS: Novel, theory-based approaches will be necessary to improve vaccine confidence. One approach to promoting public health, derived from the SEM, may be to use trusted microinfluencers on social media platforms, such as local community pharmacists and community leaders.

Biological Role of Arrestin-1 Oligomerization.

Members of the arrestin superfamily have great propensity of self-association, but the physiological significance of this phenomenon is unclear. To determine the biological role of visual arrestin-1 oligomerization in rod photoreceptors, we expressed mutant arrestin-1 with severely impaired self-association in mouse rods and analyzed mice of both sexes. We show that the oligomerization-deficient mutant is capable of quenching rhodopsin signaling normally, as judged by electroretinography and single-cell recording. Like wild type, mutant arrestin-1 is largely excluded from the outer segments in the dark, proving that the normal intracellular localization is not due the size exclusion of arrestin-1 oligomers. In contrast to wild type, supraphysiological expression of the mutant causes shortening of the outer segments and photoreceptor death. Thus, oligomerization reduces the cytotoxicity of arrestin-1 monomer, ensuring long-term photoreceptor survival.SIGNIFICANCE STATEMENT Visual arrestin-1 forms dimers and tetramers. The biological role of its oligomerization is unclear. To test the role of arrestin-1 self-association, we expressed oligomerization-deficient mutant in arrestin-1 knock-out mice. The mutant quenches light-induced rhodopsin signaling like wild type, demonstrating that in vivo monomeric arrestin-1 is necessary and sufficient for this function. In rods, arrestin-1 moves from the inner segments and cell bodies in the dark to the outer segments in the light. Nonoligomerizing mutant undergoes the same translocation, demonstrating that the size of the oligomers is not the reason for arrestin-1 exclusion from the outer segments in the dark. High expression of oligomerization-deficient arrestin-1 resulted in rod death. Thus, oligomerization reduces the cytotoxicity of high levels of arrestin-1 monomer.

RBX2 maintains final retinal cell position in a DAB1-dependent and -independent fashion.

The laminated structure of the retina is fundamental for the organization of the synaptic circuitry that translates light input into patterns of action potentials. However, the molecular mechanisms underlying cell migration and layering of the retina are poorly understood. Here, we show that RBX2, a core component of the E3 ubiquitin ligase CRL5, is essential for retinal layering and function. RBX2 regulates the final cell position of rod bipolar cells, cone photoreceptors and Muller glia. Our data indicate that sustained RELN/DAB1 signaling, triggered by depletion of RBX2 or SOCS7 - a CRL5 substrate adaptor known to recruit DAB1 - causes rod bipolar cell misposition. Moreover, whereas SOCS7 also controls Muller glia cell lamination, it is not responsible for cone photoreceptor positioning, suggesting that RBX2, most likely through CRL5 activity, controls other signaling pathways required for proper cone localization. Furthermore, RBX2 depletion reduces the number of ribbon synapses and disrupts cone photoreceptor function. Together, these results uncover RBX2 as a crucial molecular regulator of retina morphogenesis and cone photoreceptor function.

Tracking distinct microglia subpopulations with photoconvertible Dendra2 in vivo.

BACKGROUND: The ability to track individual immune cells within the central nervous system has revolutionized our understanding of the roles that microglia and monocytes play in synaptic maintenance, plasticity, and neurodegenerative diseases. However, distinguishing between similar subpopulations of mobile immune cells over time during episodes of neuronal death and tissue remodeling has proven to be challenging. METHODS: We recombineered a photoconvertible fluorescent protein (Dendra2; D2) downstream of the Cx3cr1 promoter commonly used to drive expression of fluorescent markers in microglia and monocytes. Like the popular Cx3cr1-GFP line (Cx3cr1+/GFP), naïve microglia in Cx3cr1-Dendra2 mice (Cx3cr1+/D2) fluoresce green and can be noninvasively imaged in vivo throughout the CNS. In addition, individual D2-expressing cells can be photoconverted, resulting in red fluorescence, and tracked unambiguously within a field of green non-photoconverted cells for several days in vivo. RESULTS: Dendra2-expressing retinal microglia were noninvasively photoconverted in both ex vivo and in vivo conditions. Local in vivo D2 photoconversion was sufficiently robust to quantify cell subpopulations by flow cytometry, and the protein was stable enough to survive tissue processing for immunohistochemistry. Simultaneous in vivo fluorescence imaging of Dendra2 and light scattering measurements (Optical Coherence Tomography, OCT) were used to assess responses of individual microglial cells to localized neuronal damage and to identify the infiltration of monocytes from the vasculature in response to large scale neurodegeneration. CONCLUSIONS: The ability to noninvasively and unambiguously track D2-expressing microglia and monocytes in vivo through space and time makes the Cx3cr1-Dendra2 mouse model a powerful new tool for disentangling the roles of distinct immune cell subpopulations in neuroinflammation.

Systematic review of noncognitive factors influence on health professions students' academic performance.

Increased importance has been placed on noncognitive skills in professional development and by accrediting bodies of health professions programs in recent years. Therefore, the purpose of this study was to conduct a comprehensive systematic review of evidence examining effects of academic resilience, grit, perceived stress, locus of control, and Big Five Personality Traits on academic performance of health professions students. A literature search of peer-reviewed, English-language articles describing select noncognitive factors was performed using seven databases. Searches were performed from the earliest index date through May 2020. The following data from included studies were extracted and summarized: research design hierarchy, hierarchy of study outcomes (modified from Kirkpatrick), association between noncognitive factors and academic outcomes, and quality assessment criteria. 149 articles met inclusion criteria. Almost 80% of studies were Level III (observational). Medical students were the most frequently studied population (n = 73 articles). The most studied academic outcome was grade point average (n = 61). Perceived stress and Big Five Personality Traits accounted for greater than 50% of studies. Most studies were rated as fair to good quality. Associations between noncognitive factors and academic outcomes were largely inconsistent, although greater perceived stress was generally associated with poorer academic performance outcomes, while higher conscientiousness, academic resilience, and grit were generally associated with better outcomes. This systematic review represents a large body of evidence concerning select noncognitive factors and their association with academic performance of health professions students. Support services addressing noncognitive factors should be deliberated and tailored for specific health professions education programs and student populations.

Dysregulated CD38 Expression on Peripheral Blood Immune Cell Subsets in SLE.

Given its uniformly high expression on plasma cells, CD38 has been considered as a therapeutic target in patients with systemic lupus erythematosus (SLE). Herein, we investigate the distribution of CD38 expression by peripheral blood leukocyte lineages to evaluate the potential therapeutic effect of CD38-targeting antibodies on these immune cell subsets and to delineate the use of CD38 as a biomarker in SLE. We analyzed the expression of CD38 on peripheral blood leukocyte subsets by flow and mass cytometry in two different cohorts, comprising a total of 56 SLE patients. The CD38 expression levels were subsequently correlated across immune cell lineages and subsets, and with clinical and serologic disease parameters of SLE. Compared to healthy controls (HC), CD38 expression levels in SLE were significantly increased on circulating plasmacytoid dendritic cells, CD14++CD16+ monocytes, CD56+ CD16dim natural killer cells, marginal zone-like IgD+CD27+ B cells, and on CD4+ and CD8+ memory T cells. Correlation analyses revealed coordinated CD38 expression between individual innate and memory T cell subsets in SLE but not HC. However, CD38 expression levels were heterogeneous across patients, and no correlation was found between CD38 expression on immune cell subsets and the disease activity index SLEDAI-2K or established serologic and immunological markers of disease activity. In conclusion, we identified widespread changes in CD38 expression on SLE immune cells that highly correlated over different leukocyte subsets within individual patients, but was heterogenous within the population of SLE patients, regardless of disease severity or clinical manifestations. As anti-CD38 treatment is being investigated in SLE, our results may have important implications for the personalized targeting of pathogenic leukocytes by anti-CD38 monoclonal antibodies.

Disrupted Blood-Retina Lysophosphatidylcholine Transport Impairs Photoreceptor Health But Not Visual Signal Transduction.

Retinal photoreceptor cells contain the highest concentration of docosahexaenoic acid (DHA) in our bodies, and it has been long assumed that this is critical for supporting normal vision. Indeed, early studies using DHA dietary restriction documented reduced light sensitivity by DHA-deprived retinas. Recently, it has been demonstrated that a major route of DHA entry in the retina is the delivery across the blood-retina barrier by the sodium-dependent lipid transporter, Mfsd2a. This discovery opened a unique opportunity to analyze photoreceptor health and function in DHA-deprived retinas using the Mfsd2a knock-out mouse as animal model. Our lipidome analyses of Mfsd2a-/- retinas and outer segment membranes corroborated the previously reported decrease in the fraction of DHA-containing phospholipids and a compensatory increase in phospholipids containing arachidonic acid. We also revealed an increase in the retinal content of monounsaturated fatty acids and a reduction in very long chain fatty acids. These changes could be explained by a combination of reduced DHA supply to the retina and a concomitant upregulation of several fatty acid desaturases controlled by sterol regulatory element-binding transcription factors, which are upregulated in Mfsd2a-/- retinas. Mfsd2a-/- retinas undergo slow progressive degeneration, with ∼30% of photoreceptor cells lost by the age of 6 months. Despite this pathology, the ultrastructure Mfsd2a-/- photoreceptors and their ability to produce light responses were essentially normal. These data demonstrate that, whereas maintaining the lysophosphatidylcholine route of DHA supply to the retina is essential for long-term photoreceptor survival, it is not important for supporting normal phototransduction.SIGNIFICANCE STATEMENT Phospholipids containing docosahexaenoic acid (DHA) are greatly enriched in the nervous system, with the highest concentration found in the light-sensitive membranes of photoreceptor cells. In this study, we analyzed the consequences of impaired DHA transport across the blood-retina barrier. We have found that, in addition to a predictable reduction in the DHA level, the affected retinas undergo a complex, transcriptionally-driven rebuilding of their membrane lipidome in a pattern preserving the overall saturation/desaturation balance of retinal phospholipids. Remarkably, these changes do not affect the ability of photoreceptors to produce responses to light but are detrimental for the long-term survival of these cells.

Racial and Regional Disparities in Outcomes Among Veterans Initially Adherent to Oral Antidiabetic Therapies: an Observational Cohort Study.

BACKGROUND: Adherence to prescribed medications is connected with, but is not a guarantee of, improved disease management and health outcomes. It remains unclear whether underlying health disparities exist among patients adherent to therapy and whether differences in outcomes vary by race and residential areas of the country. OBJECTIVE: To determine the extent of racial and regional variation in outcomes within 5 years of oral antidiabetic drug initiation among veterans adherent to therapy. DESIGN: Retrospective cohort study of 83,265 US Veterans Health Administration data, 2002-2014 PATIENTS: US veterans with uncomplicated diabetes and taking oral antidiabetic agents MAIN MEASURES: Veterans initially adherent to oral antidiabetic therapy were followed for up to 5 years, and comparisons focused on differences between non-Hispanic White and non-Hispanic Black veterans across geographic region and residential type (urban or rural). Outcomes included composite cardiovascular events, composite cerebrovascular events, or all-cause mortality using Poisson and adjusted Cox proportional hazards models. KEY RESULTS: Cardiovascular event and all-cause mortality rates differed by race and region, while urban/rural differences were evident for cerebrovascular events and all-cause mortality. For non-Hispanic Blacks, the mortality rate was half that compared to non-Hispanic Whites (6.5 [95% CI 5.8-7.2] versus 13.3 [95% CI 12.9-13.8], p < 0.0001). Compared to the Northeast, all other regions had higher adjusted hazards for cardiovascular or cerebrovascular events (with a single exception), but no regional differences in all-cause mortality were observed. Models with interactions demonstrated that racial differences in cardiovascular events and all-cause mortality were isolated to the Midwest (HR 1.99 [95% CI 1.301-3.06; HR 1.64 [95% CI 1.210-2.215]) and South (HR 1.69 [85% CI 1.347-2.131]; HR 1.27 [95% CI 1.095-1.470]). CONCLUSIONS: Despite adherence to therapy, differences in outcomes are likely among veterans with diabetes based on race and geography. Localized analyses may uncover specific social determinants contributing to differences in outcomes.

In vivo optophysiology reveals that G-protein activation triggers osmotic swelling and increased light scattering of rod photoreceptors.

The light responses of rod and cone photoreceptors have been studied electrophysiologically for decades, largely with ex vivo approaches that disrupt the photoreceptors' subretinal microenvironment. Here we report the use of optical coherence tomography (OCT) to measure light-driven signals of rod photoreceptors in vivo. Visible light stimulation over a 200-fold intensity range caused correlated rod outer segment (OS) elongation and increased light scattering in wild-type mice, but not in mice lacking the rod G-protein alpha subunit, transducin (Gαt), revealing these responses to be triggered by phototransduction. For stimuli that photoactivated one rhodopsin per Gαt the rod OS swelling response reached a saturated elongation of 10.0 ± 2.1%, at a maximum rate of 0.11% s-1 Analyzing swelling as osmotically driven water influx, we find the H2O membrane permeability of the rod OS to be (2.6 ± 0.4) × 10-5 cm⋅s-1, comparable to that of other cells lacking aquaporin expression. Application of Van't Hoff's law reveals that complete activation of phototransduction generates a potentially harmful 20% increase in OS osmotic pressure. The increased backscattering from the base of the OS is explained by a model combining cytoplasmic swelling, translocation of dissociated G-protein subunits from the disc membranes into the cytoplasm, and a relatively higher H2O permeability of nascent discs in the basal rod OS. Translocation of phototransduction components out of the OS may protect rods from osmotic stress, which could be especially harmful in disease conditions that affect rod OS structural integrity.

Evaluation of naloxone access, pricing, and barriers to dispensing in Tennessee retail community pharmacies.

OBJECTIVES: Tennessee has one of the highest rates of opioid prescribing in the United States; therefore, the objectives of this study were to examine availability, pricing, and pharmacist-initiated recommendations of naloxone in retail community pharmacies in Eastern and Western Tennessee; to identify the most common barriers to naloxone dispensing and strategies to improve access; and to determine regional differences in access to naloxone. DESIGN: A cross-sectional survey conducted via telephone. SETTING AND PARTICIPANTS: All retail community pharmacies located in the most populous counties in the eastern and western regions of Tennessee were eligible for inclusion, as were all retail community pharmacies in the 5 counties in each region that had the highest rates of opioid prescriptions (316 pharmacies identified in 12 counties). OUTCOME MEASURES: Outcome measures included availability, price, and pharmacist-initiated recommendations of naloxone products, barriers to dispensing, and suggestions to improve naloxone access. Survey responses were summarized as descriptive statistics. Chi-square, independent samples t test, and inductive content analysis were conducted. RESULTS: Response rate was 56.3%. Most participants (92.7%) reported that naloxone (Narcan) was available from their pharmacies at a mean cash price of $132.49, with no statistically significant differences between regions. The most commonly reported barrier was cost (70.2%). When queried about recommendations to various groups at a high risk of overdose, as advised by the U.S. Department of Health and Human Services, 42.1% to 69.1% of pharmacies reported recommending naloxone to at least 50% of high-risk patients. Suggestions to increase naloxone access included lowering the cost and improving naloxone-related education for patients, pharmacists, and other providers. CONCLUSION: Although Narcan was widely available, cost was a frequently cited barrier to dispensing. Pharmacist-initiated recommendations for coprescribing and dispensing naloxone to patients at a high risk of overdose were limited. Addressing cost issues in addition to increasing patient and pharmacist education concerning the use and benefit of naloxone were suggested to improve naloxone access.