Chemically induced cone degeneration in the 13-lined ground squirrel.

Animal models of retinal degeneration are critical for understanding disease and testing potential therapies. Inducing degeneration commonly involves the administration of chemicals that kill photoreceptors by disrupting metabolic pathways, signaling pathways, or protein synthesis. While chemically induced degeneration has been demonstrated in a variety of animals (mice, rats, rabbits, felines, 13-lined ground squirrels (13-LGS), pigs, chicks), few studies have used noninvasive high-resolution retinal imaging to monitor the in vivo cellular effects. Here, we used longitudinal scanning light ophthalmoscopy (SLO), optical coherence tomography, and adaptive optics SLO imaging in the euthermic, cone-dominant 13-LGS (46 animals, 52 eyes) to examine retinal structure following intravitreal injections of chemicals, which were previously shown to induce photoreceptor degeneration, throughout the active season of 2019 and 2020. We found that iodoacetic acid induced severe pan-retinal damage in all but one eye, which received the lowest concentration. While sodium nitroprusside successfully induced degeneration of the outer retinal layers, the results were variable, and damage was also observed in 50% of contralateral control eyes. Adenosine triphosphate and tunicamycin induced outer retinal specific damage with varying results, while eyes injected with thapsigargin did not show signs of degeneration. Given the variability of damage we observed, follow-up studies examining the possible physiological origins of this variability are critical. These additional studies should further advance the utility of chemically induced photoreceptor degeneration models in the cone-dominant 13-LGS.

Quantifying optic nerve axons in a cat glaucoma model by a semi-automated targeted counting method.

PURPOSE: To describe and validate a semi-automated targeted sampling (SATS) method for quantifying optic nerve axons in a feline glaucoma model. METHODS: Optic nerve cross sections were obtained from 15 cats, nine with mild to severe glaucoma and six with normal eyes. Optic nerves were dissected, fixed in paraformaldehyde and glutaraldehyde, and processed for light microscopy by resin embedding, sectioning, and staining of axon myelin sheaths with 1% p-phenylenediamine before axon quantification. Commercially available image analysis software was used as a semi-automated axon counting tool (SCT) and was first validated by comparison with a manual axon count (MAC). This counting tool was then used in a SATS method performed by three masked raters and in a semi-automated full count (SAFC) method performed by a single observer. Correlation was assessed between the SCT and MAC using a linear model and analysis of covariance (ANCOVA). Correlation between the SATS and SAFC methods was calculated and the bias, systematic errors, and variance component assessed. The intraclass correlation coefficient (ICC) was determined to establish inter-rater agreement. In addition, the time required to perform the SATS and SAFC methods was evaluated. RESULTS: Correlation between the axon counts obtained by the SCT and MAC was strong (r = 0.9985). There was evidence of an overcounting of axons by the SCT compared to the MAC with a percentage error rate of 13.0% (95% confidence interval [CI] 11.0%, 15.1%). Both the correlation of SATS count (average per rater) to SAFC (r = 0.9891) and inter-rater agreement (ICC = 0.986) were high. The SATS method presented an overall positive counting error (p<0.001) when compared to the SAFC, consistent with a fixed percentage overestimation of 11.2% (95% CI 8.3%, 14.2%) of the full count. The average time required to quantify axons by the SATS method was 10.9 min, only 27% of that required to conduct the SAFC. CONCLUSIONS: Our data demonstrate that the SATS method provides a practical, rapid, and reliable means of estimating axon counts in the optic nerves of cats with glaucoma.

Human iPSC-derived photoreceptor transplantation in the cone dominant 13-lined ground squirrel.

Several retinal degenerations affect the human central retina, which is primarily comprised of cones and is essential for high acuity and color vision. Transplanting cone photoreceptors is a promising strategy to replace degenerated cones in this region. Although this approach has been investigated in a handful of animal models, commonly used rodent models lack a cone-rich region and larger models can be expensive and inaccessible, impeding the translation of therapies. Here, we transplanted dissociated GFP-expressing photoreceptors from retinal organoids differentiated from human induced pluripotent stem cells into the subretinal space of damaged and undamaged cone-dominant 13-lined ground squirrel eyes. Transplanted cell survival was documented via noninvasive high-resolution imaging and immunohistochemistry to confirm the presence of human donor photoreceptors for up to 4 months posttransplantation. These results demonstrate the utility of a cone-dominant rodent model for advancing the clinical translation of cell replacement therapies.

Social determinants of health correlations and resource usefulness at a Milwaukee free clinic for uninsured individuals: A cross-sectional study.

Introduction: Addressing social determinants of health (SDOH) is fundamental to improving health outcomes. At a student-run free clinic, we developed a screening process to understand the SDOH needs and resource utilization of Milwaukee's uninsured population. Methods: In this cross-sectional study, we screened adult patients without health insurance (N = 238) for nine traditional SDOH needs as well as their access to dental and mental health care between October 2021 and October 2022. Patients were surveyed at intervals greater than or equal to 30 days. We assessed correlations between SDOH needs and trends in patient-reported resource usefulness. Results: Access to dental care (64.7%) and health insurance (51.3%) were the most frequently endorsed needs. We found significant correlations (P ≤ 0.05) between various SDOH needs. Notably, mental health access needs significantly correlated with dental (r = 0.41; 95% CI = 0.19, 0.63), medications (r = 0.51; 95% CI = 0.30, 0.72), utilities (r = 0.39; 95% CI = 0.17, 0.61), and food insecurity (r = 0.42; 95% CI = 0.19, 0.64). Food-housing (r = 0.55; 95% CI = 0.32, 0.78), housing-medications (r = 0.58; 95% CI = 0.35, 0.81), and medications-food (r = 0.53; 95% CI = 0.32, 0.74) were significantly correlated with each other. Longitudinal assessment of patient-reported usefulness informed changes in the resources offered. Conclusions: Understanding prominent SDOH needs can inform resource offerings and interventions, addressing root causes that burden under-resourced patients. In this study, patient-reported data about resource usefulness prompted the curation of new resources and volunteer roles. This proof-of-concept study shows how longitudinally tracking SDOH needs at low-resource clinics can inform psychosocial resources.

Exploring Mechanisms of Action in Exposure-Based Cognitive Behavioral Therapy for Eating Disorders: The Role of Eating-Related Fears and Body-Related Safety Behaviors.

Evidence-based cognitive behavioral therapy for eating disorders includes a component of exposure therapy, which involves patients confronting feared eating and body-related stimuli while preventing safety behaviors. With recent research demonstrating that eating-related fears and safety behaviors are central to eating disorder pathology, there is increased emphasis on improving the efficacy of exposure therapy in eating disorders. Doing so will require a better understanding of important mechanisms of action in this treatment. The present study explored how changes during treatment in eating-related fears and avoidance as well as body-related safety behaviors influence overall treatment outcomes. Individuals with eating disorders (N = 71) receiving exposure-based treatment completed measures of global eating disorder severity at admission and discharge. Hypothesized mechanisms of action were also assessed at admission and discharge as well as at a 2-week time point after beginning treatment. Path modeling analyses showed that decreased eating-related cognitions (feared concerns about eating) and emotions (anxiety about eating) at the 2-week time point were prospectively predictive of lowered global eating disorder symptom severity at discharge. Additionally, reduced body checking and avoidance behaviors after 2 weeks of treatment were also associated with lower eating disorder severity at discharge. These findings highlight the importance of exposure-based therapy in eating disorders and the need to uniquely address eating-related fears and safety behaviors.

Patient Barriers for Weight Management Among African American Women.

PURPOSE: The primary aim of this study was to assess the perceptions of local African American women who are overweight or obese using semi-structured focus groups to identify barriers to weight management and factors that support strategy success. The secondary aim of this study was to determine recommendations for patient-centered weight management interventions established specifically for African American women in the Milwaukee-area community. METHODS: Three semi-structured focus groups to explore barriers to weight management were performed among women patients. Participants (N=41) were recruited via email, postal mail, and phone as available from an academic medical center in Milwaukee, Wisconsin. Focus group discussions were transcribed verbatim, reviewed by the study team, and coded based on recurring themes within and across interviews. Responses were analyzed by frequency of occurrence using qualitative computer software. RESULTS: Five primary barriers to weight management were identified from focus groups: food choices, lifestyle changes, social support, locus of control, and health education. Based on participant reports, improvements to present practice and health literacy for patients may be merited. There was expressed interest by patients for being involved in future research and development of patient-centered interventions. CONCLUSIONS: This study provides support for the use of a community-based participatory research approach in determining appropriate considerations for weight management interventions suitable for this patient population. Future research should include stakeholders not included in this study, such as community organization leaders, and primary care physicians to develop a refined intervention targeting the primary barriers to weight management.