The role of extended reality in optometry education: a narrative review.

The evolution of digitally based pedagogies, such as extended reality (XR) - a group of simulated learning environments that include virtual simulation, virtual reality, and augmented reality - has prompted optometry educators to seek evidence to guide the implementation of these teaching and learning activities within their curricula. Looking more broadly across the medical and allied health fields, there is a wealth of evidence to guide the incorporation of XR, as it is increasingly being integrated into the curricula of other select health professions disciplines. Educators from these disciplines continue to explore and embed XR in practice. This narrative review summarises the findings and appraises the literature on the use of XR in optometry education. It identifies the learning domains in which XR has been implemented in optometry education and proposes areas for further investigation. The review questions the technology-focused approach that has driven the literature within the review and calls for richer pedagogical foundations with suggestions for future research agendas. As such, this narrative review provides optometry educators with new ways of understanding XR and its relationship with the curriculum.

Ocular Biometry Percentile Curves and Their Relation to Myopia Development in Indian Children.

Background: The aim of the present study was to provide ocular biometry percentile values for Indian children between the ages of 6 and 12 and to validate the usefulness of centiles in predicting myopia development. Methods: The study was part of a longitudinal study-the Sankara Nethralaya Tamil Nadu Essilor Myopia Study (STEM), where objective refraction and ocular biometry were measured for children studying in grades 1, 4, and 6 at baseline (2019-2020). These data were used to generate ocular biometry percentile curves (both for axial length (AL) and AL/corneal curvature (AL/CR) ratios). The usefulness of percentile values in predicting myopia development was estimated from follow-up data (2022). Results: The total number of children in the three grades at baseline was 4514 (age range 6 to 12). Boys represented 54% (n = 2442) of the overall sample. The prevalence of myopia at baseline was 11.7% (95% CI from 10.8 to 12.7%) in these three grades. Both the AL and AL/CR ratio centiles showed a linear trend with an increase in AL and AL/CR with increasing grades (p < 0.001) for all percentiles (2, 5, 10, 25, 50, 75, 90, 95, 98, and 99) when stratified by sex. In the follow-up data (n = 377), the 75th and 50th percentiles of the AL/CR ratio had an area under the curve (AUC) of 0.79 and 0.72 to predict myopia onset for grade 4 and 6 children at baseline. Combining baseline AL with the centile shift in follow-up as a predictor increased the AUC to 0.83. Conclusions: The present study has provided centile values specific for Indian children between the ages of 6 and 12 to monitor and intervene where children are at a higher risk of myopia development.

Programmatically Localizing Diabetic Retinopathy Features in 45-Degree Retinal Photographs Using Anatomical Colocation.

Background: The aim in this study was to investigate the localization of diabetic retinopathy features at the posterior pole. Methods: This study extracted diabetic retinopathy feature locations from 757 macula-centered 45-degree fundus photographs in the publicly available DDR dataset. Arteriole and venule locations were also extracted from the RITE (n = 35) and IOSTAR (n = 29) datasets. Images were normalized to collocate optic disc and macula positions, and feature positions were collated to generate a frequency distribution matrix. Sørensen-Dice coefficients were calculated to compare the location of different features. Results: Arterioles occurred in two main, distinct arcuate patterns. Venules showed a more diffuse distribution. Microaneurysms were diffusely located around the posterior pole. Hemorrhages and exudates occurred more frequently at the temporal aspect of the macula. Cotton wool spots occurred in a region approximating the radial peripapillary capillaries. Intraretinal microvascular abnormalities and neovascularization were seen throughout the posterior pole, with neovascularization at the disc (n = 65) being more common than neovascularization elsewhere (n = 46). Venous beading occurred primarily between the first and third bifurcations of the venules. Diabetic retinopathy overall was more frequent in the temporal aspect of the macula. The location of cotton wool spots and exudates showed moderate similarity (0.52) when all data were considered, reducing to low similarity (0.18) when areas of low frequency were removed. Conclusions: Diabetic retinopathy occurs throughout the posterior pole but is more frequent in the temporal aspect of the macula. Understanding the location of diabetic retinopathy features may help inform visual search strategies for diabetic retinopathy screening.

A guide to optometrists for appraising and using artificial intelligence in clinical practice.

Artificial intelligence systems are becoming increasingly available as diagnostic aids for optometric practice. These perform well but are often 'black-box' systems offering little or no insight into how a decision was reached. While there is potential for artificial intelligence to improve patient outcomes, clinicians without training in computer science may find it difficult to ascertain whether these technologies are suitable for their practice, or how they should be used. This review provides an overview of how artificial intelligence systems work in optometry, their strengths, weaknesses, and regulatory considerations. A checklist is provided for appraising a system, covering regulatory approvals, ascertaining what the system can and cannot do, how it can be used in practice, whether it is suitable for the clinical population, and whether the outputs can be explained. Artificial intelligence has the potential to improve accuracy and efficiency in many areas of optometry if used correctly, and should be embraced by clinicians as an assistive tool.

Virtual simulated international placements as an innovation for internationalisation in undergraduate programs: a mixed methods study.

BACKGROUND: Inherent features in virtual simulation could be utilised to deliver collaborative global education that is inclusive, accessible, and valued by students and facilitators. The aim of this study was to evaluate the impact of the International Eyecare Community (IEC) platform's virtual simulated international placements (VSIP) in optometric education. METHODS: An international, multi-center, cross-sectional mixed methods study with Deakin University, Australia, and the Elite School of Optometry, India, was used to evaluate the impact of VSIP in the IEC using pre-existing deidentified data collected from teaching and learning activities within the optometry course curriculum. Data on students and facilitators perceptions of the VSIP were collected through deidentified transcripts from focus group discussions. The data were interpreted using descriptive statistics and qualitative analysis using constant comparison for thematic analysis. RESULTS: A total of 64 out of 167 student participants completed survey responses (39%) and 46 out of 167 (28%) completed self-reflective inventories. Focus groups with 6 student participants and 6 facilitator participants were recorded and analysed. Student participants reported the IEC was relevant (98% agreement) and motivated them to apply theoretical knowledge to a clinical context (97% agreement). The themes identified through qualitative analysis were: factors inherent to the virtual simulation that enabled learning through VSIP, the VSIP supported cognitive apprenticeship, VSIP enabled clinical learning for optometric education, VSIP' role in cross-cultural professional identity development in optometry students. CONCLUSION: The study found that the VSIP platform helped to motivate students to learn and improve their clinical skills. The VSIP was considered a potential supplement to physical clinical placements and could revolutionize global optometric education by offering co-learning across cultures.

Cardiovascular and renal profiles in rat offspring that do not undergo catch-up growth after exposure to maternal protein restriction.

Maternal protein restriction is often associated with structural and functional sequelae in offspring, particularly affecting growth and renal-cardiovascular function. However, there is little understanding as to whether hypertension and kidney disease occur because of a primary nephron deficit or whether controlling postnatal growth can result in normal renal-cardiovascular phenotypes. To investigate this, female Sprague-Dawley rats were fed either a low-protein (LP, 8.4% protein) or normal-protein (NP, 19.4% protein) diet prior to mating and until offspring were weaned at postnatal day (PN) 21. Offspring were then fed a non 'growth' (4.6% fat) which ensured that catch-up growth did not occur. Offspring growth was determined by weight and dual energy X-ray absorptiometry. Nephron number was determined at PN21 using the disector-fractionator method. Kidney function was measured at PN180 and PN360 using clearance methods. Blood pressure was measured at PN360 using radio-telemetry. Body weight was similar at PN1, but by PN21 LP offspring were 39% smaller than controls (Pdiet < 0.001). This difference was due to proportional changes in lean muscle, fat, and bone content. LP offspring remained smaller than NP offspring until PN360. In LP offspring, nephron number was 26% less in males and 17% less in females, than NP controls (Pdiet < 0.0004). Kidney function was similar across dietary groups and sexes at PN180 and PN360. Blood pressure was similar in LP and NP offspring at PN360. These findings suggest that remaining on a slow growth trajectory after exposure to a suboptimal intrauterine environment does not lead to the development of kidney dysfunction and hypertension.

Myopia and Its Association with Near Work, Outdoor Time, and Housing Type among Schoolchildren in South India.

SIGNIFICANCE: In this comprehensive assessment of environmental associations with refractive status among schoolchildren in India, outdoor time was the key modifiable risk factor associated with myopia rather than time spent on near work. PURPOSE: This study aimed to investigate the environmental risk factors associated with myopia among adolescent schoolchildren in South India. METHODS: Children in grades 8 to 10 from 11 schools in Tamil Nadu, South India, underwent eye examination and risk factor assessments through a modified version of the Sydney myopia questionnaire. Time spent on near work and outdoors was analyzed after division into three groups based on tertiles. Mixed-effects logistic regression was performed to assess the factors associated with myopia. RESULTS: A total of 3429 children (response rate, 78.4%) provided both questionnaire and refraction data. The mean (standard deviation) age was 14 (0.93) years with an equal distribution of sexes. Myopia was present among 867 children (noncycloplegic spherical equivalent refraction, ≤-0.75 D). Refraction was not associated with near work tertiles ( P = .22), whereas less time outdoors was associated with higher myopic refractions ( P = .01). Refraction shifted toward increased myopia with an increase in the near-work/outdoor time ratio ( P = .005). Children living in apartment housing had a higher prevalence of myopia compared with other types of housing ( P < .001). In multivariate analysis, increased time outdoors was a protective factor against myopia (odds ratio, 0.79; 95% confidence interval, 0.63 to 0.99; P = .04), whereas living in apartment housing (odds ratio, 1.27; 95% confidence interval, 1.04 to 1.55; P = .02) was a significant risk factor. CONCLUSIONS: In this cohort of Indian children, outdoor time, increased near-work/outdoor time ratio, and type of housing were the factors associated with myopia. Policies should target implementing a balance between near-work and outdoor time among children.

Developing culturally safe education practices in optometry schools across Australia and Aotearoa New Zealand.

Access to culturally safe health services is a basic human right, however through the lasting effects of colonisation, oppression, and systemic racism, the individual and community health of Indigenous peoples in Australia and Aotearoa New Zealand have been severely impacted. The Aboriginal and Torres Strait Islander Health and Cultural Safety Strategy of the Australian Health Practitioners Regulation Agency, and the Standards of Cultural Competence and Cultural Safety of the Optometrists and Dispensing Opticians Board of New Zealand, recognise the importance of access to safe health care for Aboriginal, Torres Strait Islander and Maori patients, which encompasses both clinical competency and cultural safety. Universities have an ongoing responsibility to ensure their learning and teaching activities result in graduates being able to provide culturally safe practice. This article highlights the emergence of culturally safe practices in the Australian and Aotearoa New Zealand optometry curricula over the last five years incorporating Indigenous ways of knowing, being and doing into the curricula, understanding the local Indigenous histories and contexts, the adoption of online cultural education modules, and clinical placement partnerships with local Indigenous communities. Whilst there is still much work to do to achieve the goal of graduating culturally safe optometrists, this paper focuses on features that enable or impede progress in the development of culturally safe practices within the optometry programmes to improve eye health equity for Indigenous recognise the diversity of Indigenous cultures across Australia and NZ.

Supervisor experiences of extended clinical placements in optometry: a mixed methods study.

BACKGROUND: In Australia, optometry students have traditionally undertaken their clinical training in short-block rotations at University-led teaching clinics in metropolitan locations. Demand for clinical placements is growing as the number of optometry students steadily increases. As such, universities and clinical education providers must look for more diverse methods of student placement. Extended clinical placements in community-based settings are one alternative: a model similar to the longitudinal clerkships in medicine. This study aimed to explore the experience of extended clinical placements from the perspective of the optometrists who supervised students. It also sought to determine whether there were differences in views between metropolitan and rural practitioners. METHODS: This mixed methods study included a survey and interviews with optometrists who had previously supervised Deakin University optometry students on an extended 26-week (2 x 13-weeks) clinical placement. Lines of enquiry focused on; the benefits and challenges associated with extended placements; areas for improvement; duration of the placement; and willingness to supervise further students. Interviews were transcribed verbatim and analysed using Braun and Clarke's 6 step method of thematic analysis with a qualitative descriptive approach. RESULTS: Supervisors felt that hosting a student prompted greater reflective practice and critical appraisal of clinical decisions. The extended nature of the placement was thought to foster greater immersion in the clinical setting and community for the students and establish a stronger relationship between supervisor and student. Supervisors recognised the importance of role-modelling and mentoring the next generation of optometrists however noted that taking on a student was a sizeable commitment. Willingness to host a student was not dependent on the supervisor's location (rural vs metropolitan) p = 0.57. However, interviews uncovered motivations that were unique to supervisors residing in rural locations, such as succession planning. CONCLUSION: Overall, supervisors were positive about the value of student extended clinical placement in optometry and felt that it was a fulfilling and professionally beneficial experience. Lack of time and financial remuneration were the key downsides highlighted. Schools of optometry might carefully consider engaging in discussion about the duration of such placements, but 26 weeks was considered appropriate by supervisors.

The perceived value and impact of virtual simulation-based education on students' learning: a mixed methods study.

BACKGROUND: Virtual simulations are used throughout healthcare training programs to enable development of clinical skills, however the potential for virtual simulation to enhance cognitive and affective skills is less well understood. This study explored pre-clinical optometry students' perceptions of the impact of virtual simulation on the development of core competency skills including patient-centred care, communication, scientific literacy, and evidence-based practice. METHODS: A mixed methods study was conducted using pre-existing anonymized data from an electronic survey distributed to pre-clinical optometry students enrolled in the double degree Bachelor of Vision Science/Master of Optometry at Deakin University, Australia. The data were interpreted using descriptive statistics and qualitative analysis using constant comparison for thematic analysis. RESULTS: A total of 51 responses were analyzed. Students reported that virtual simulation motivated them to become an optometrist (93%) and to learn beyond the course material (77%). Students reported that after participating in the virtual simulation, their core competency skills improved: patient-centered care (100%) evidence-based practice (93%) and clinical reasoning (93%). The themes identified through qualitative analysis were: enablers to cognitive experience in virtual simulation in optometry education, realism of the virtual simulation design, dimensions of fidelity in virtual simulations design replicated the complexity of the optometric environment, virtual simulation as an enabler for learning and assessment in optometry education, a place to develop cognitive and affective skills and application of learning in the virtual simulation developed an appreciation of future roles and professional identity. CONCLUSION: Optometry students perceived virtual simulation in optometric education as a valuable training and assessment strategy enabled by qualities that generate contextual, cognitive, functional, task and psychological fidelity. The data provide insight to inform how optometry educators can incorporate simulation into the curriculum.

Effects of tracker location on the accuracy and precision of the Gazepoint GP3 HD for spectacle wearers.

Remote view eye-tracking systems are prone to errors when used on spectacle wearers due to reflections from the lenses and frame that result in inaccurate tracking. Traditionally, these trackers are situated below a computer monitor and the viewer's eye moments are recorded while they view the screen. Reflections may be influenced by the pantoscopic tilt of the spectacles, whereby the tilt angle causes incident light to be reflected to the camera. To overcome this problem, we propose mounting the tracker above the monitor to avoid these reflections and test the accuracy and precision of subjects with single vision spectacles, multifocals, and no correction, using both mounting positions. Experimental results showed that this alternate position had overall worse accuracy (4.06° ± 0.13) and precision (0.67° ± 0.05) compared to the standard configuration (2.15° ± 0.06 vs. 0.50° ± 0.03), with more invalid readings (5.91 vs. 19.19%) for single vision lens wearers. Multifocals performed better for the top-mounting position for the top portion of the monitor, suggesting higher-order aberrations from the bottom portion of the lens negatively impact data quality. Higher pantoscopic tilt angles displayed an improved accuracy for this alternate position (r(9) = - 0.69, p = 0.02), with superior accuracy for tilt angles greater than 14° compared to the standard configuration. This study quantifies the impact of spectacle wear on eye-tracking performance and suggests other alternate mounting positions may be viable in certain situations.

A cohort study for the development and validation of a reflective inventory to quantify diagnostic reasoning skills in optometry practice.

BACKGROUND: Diagnostic reasoning is an essential skill for optometry practice and a vital part of the curriculum for optometry trainees but there is limited understanding of how diagnostic reasoning is performed in optometry or how this skill is best developed. A validated and reliable self-reflective inventory for diagnostic reasoning in optometry, would enable trainees and registered practitioners to benchmark their diagnostic reasoning skills, identify areas of strength and areas for improvement. METHODS: A 41 item self-reflective inventory, the Diagnostic Thinking Inventory, used extensively in the medical field was adapted for use in optometry and called the Diagnostic Thinking Inventory for Optometry (DTI-O). The inventory measures two subdomains of diagnostic reasoning, flexibility in thinking and structured memory. Context based changes were made to the original inventory and assessed for face and content validity by a panel of experts. The inventory was administered to two groups, experienced (qualified) optometrists and second-year optometry students to establish validity and reliability of the self-reflective tool in optometry. RESULTS: Exploratory Factor Analysis uncovered 13 domain specific items were measuring a single construct, diagnostic reasoning. One misfitting item was removed following Rasch analysis. Two unidimensional subdomains were confirmed in the remaining 12 items: Flexibility in Thinking (χ2 = 12.98, P = 0.37) and Structured Memory (χ2 = 8.74, P = 0.72). The 'Diagnostic Thinking Inventory for Optometry Short' (DTI-OS) tool was formed from these items with the total and subdomain scores exhibiting strong internal reliability; Total score Cα = 0.92. External reliability was established by test-retest methodology (ICC 0.92, 95% CI 0.83-0.96, P < .001) and stacked Rasch analysis (one-way ANOVA, F = 0.07, P = 0.80). Qualified optometrists scored significantly higher (P < .001) than students, demonstrating construct validity. CONCLUSION: This study showed that the DTI-O and DTI-OS are valid and reliable self-reflective inventories to quantify diagnostic reasoning ability in optometry. With no other validated tool to measure this metacognitive skill underpinning diagnostic reasoning a self-reflective inventory could support the development of diagnostic reasoning in practitioners and guide curriculum design in optometry education.

Prevalence of myopia among urban and suburban school children in Tamil Nadu, South India: findings from the Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) Study.

PURPOSE: To report the baseline prevalence of myopia among school children in Tamil Nadu, South India from a prospective cohort study. METHODS: Children between the ages of 5 and 16 years from 11 schools in two districts of Tamil Nadu underwent vision screening. All children underwent visual acuity assessment using a Pocket Vision Screener followed by non-cycloplegic open-field autorefraction (Grand Seiko WAM-5500). Myopia was defined as a spherical equivalent (SE) refraction of ≤-0.75 D and high myopia was defined as SE ≤ -6.00 D. Distribution of refraction, biometry and factors associated with prevalence of myopia were the outcome measures. RESULTS: A total of 14,699 children completed vision screening, with 2% (357) of them having ocular abnormalities other than refractive errors or poor vision despite spectacle correction. The remaining 14,342 children (7557 boys; 52.69%) had a mean age of 10.2 (Standard Deviation [SD] 2.8) years. A total of 2502 had myopia in at least one eye, a prevalence of 17.5% (95% CI: 14.7-20.5%), and 74 (0.5%; 95% CI: 0.3-0.9%) had high myopia. Myopia prevalence increased with age (p < 0.001), but sex was not associated with myopia prevalence (p = 0.24). Mean axial length (AL; 23.08 (SD = 0.91) mm) and mean anterior chamber depth (ACD; 3.45 (SD = 0.27) mm) positively correlated with age (p < 0.001). The mean flat (K1; 43.37 (SD = 1.49) D) and steep (K2; 44.50 (SD = 1.58) D) corneal curvatures showed negative correlation with age (p = 0.02 and p < 0.001, respectively). In the multivariable logistic regression, older age and urban school location had higher odds for prevalence of myopia. CONCLUSION: The baseline prevalence of myopia among 5- to 16-year-old children in South India is larger than that found in previous studies, indicating that myopia is becoming a major public health problem in this country.

Student perspectives of extended clinical placements in optometry: a qualitative study.

BACKGROUND: The number of students enrolled in health courses at Australian universities is rising, increasing demand for clinical placements. Optometry students have historically undertaken clinical training in short-block rotations at university-led teaching clinics in metropolitan locations. This is changing, with some optometry programs adopting extended placements. These placements are conducted in community-based practices, with many incorporating a rural component to the training. This study explored factors which influence placement success and satisfaction from the perspective of optometry students. METHODS: Nine focus groups were undertaken with 42 final year optometry students upon completion of a 26-week placement (of which at least half was undertaken in a non-metropolitan area, or area where a shortage of optometrists has been identified). Focus groups were audio recorded and transcribed verbatim. Thematic analysis was conducted according to Braun and Clarke's 6 step method. RESULTS: Four key themes were identified during analysis. 'Changing identity', related to how the students grew both personally and professionally, with the extended placement being considered the vital component that allowed students to begin thinking of themselves as clinicians. The theme 'Dealing with complex dynamics and circumstances' predominantly described instances where the student-supervisor relationship was strained, resulting in high levels of anxiety made worse by a perceived lack of university support. 'Optometrist under instruction', related to students feeling that the placement was an ideal opportunity to trial the everyday reality of work without the obligation of an ongoing commitment or employment contract. Finally, the theme 'Rural practice is more rewarding', was about a chance to seek different experiences, meet new people and challenge themselves professionally. CONCLUSION: While the majority of students enjoyed their placement and felt that it was the key component of their training that equipped them for future practice, it is clear that universities and placement providers must provide both students and supervisors thorough and explicit guidance covering placement expectations. Furthermore, student support systems should be embedded into placement programs to ensure where issues arise, they are dealt with promptly and successfully. It is vital that ongoing professional development and pedagogical training for supervisors underpins continued accreditation.

The Equivalency of the Binocular Indirect Ophthalmoscope Simulator to Peer Practice: A Pilot Study.

SIGNIFICANCE: Optometric educators are constantly looking for learning and teaching approaches to improve clinical skills training. In addition, the COVID-19 pandemic has made educators scrutinize the time allocated to face-to-face teaching and practice. Simulation learning is an option, but its use must first be evaluated against traditional learning methods. PURPOSE: The purpose of this study was to compare the training of binocular indirect ophthalmoscopy skills achieved by students and optometrists through deliberate practice on the Eyesi Indirect Ophthalmoscope simulator with deliberate practice using a peer. METHODS: Students and optometrists were randomly allocated to practice on either the simulator or a peer. Binocular indirect ophthalmoscopy performance was assessed using a peer and the simulator as the patients at different time points. Knowledge and confidence were examined before and following all practice sessions using a quiz and survey. RESULTS: Significant improvements in binocular indirect ophthalmoscopy performance using either a peer or the simulator as the patient for assessment were seen after 8 hours of student practice (P < .001) and after a half-hour practice time for optometrists (P < .001). There was no significant difference in performance overall between those practicing on a simulator and those practicing on a peer (P > .05). Confidence in ability to perform the technique was lower for students who had practiced on the simulator. CONCLUSIONS: The simulator has similar efficacy to peer practice for teaching binocular indirect ophthalmoscopy to students and maintenance of this clinical skill for optometrists. Simulation does not replace the need for peer practice but may be a useful adjunct reducing the face-to-face hours required. These findings present a need for further research regarding diverse applications of the Eyesi Indirect Ophthalmoscope simulator in the curriculum for training optometry students and as a continuing professional development offering for optometrists, given the short exposure duration required to observe a significant improvement in skill.

Leptin and Melanocortin Signaling Mediates Hypertension in Offspring From Female Rabbits Fed a High-Fat Diet During Gestation and Lactation.

Maternal high-fat diet in rabbits leads to hypertension and elevated renal sympathetic nerve activity (RSNA) in adult offspring but whether this is due to adiposity or maternal programming is unclear. We gave intracerebroventricular (ICV) and ventromedial hypothalamus (VMH) administration of leptin-receptor antagonist, α-melanocyte-stimulating hormone (αMSH), melanocortin-receptor antagonist (SHU9119), or insulin-receptor (InsR) antagonist to conscious adult offspring from mothers fed a high-fat diet (mHFD), control diet (mCD), or mCD offspring fed HFD for 10d (mCD10d, to deposit equivalent fat but not during development). mHFD and mCD10d rabbits had higher mean arterial pressure (MAP, +6.4 mmHg, +12.1 mmHg, p < 0.001) and RSNA (+2.3 nu, +3.2 nu, p < 0.01) than mCD, but all had similar plasma leptin. VMH leptin-receptor antagonist reduced MAP (-8.0 ± 3.0 mmHg, p < 0.001) in mCD10d but not in mHFD or mCD group. Intracerebroventricular leptin-receptor antagonist reduced MAP only in mHFD rabbits (p < 0.05). Intracerebroventricular SHU9119 reduced MAP and RSNA in mHFD but only reduced MAP in the mCD10d group. VMH αMSH increased RSNA (+85%, p < 0.001) in mHFD rabbits but ICV αMSH increased RSNA in both mHFD and mCD10d rabbits (+45%, +51%, respectively, p < 0.001). The InsR antagonist had no effect by either route on MAP or RSNA. Hypothalamic leptin receptor and brain-derived neurotrophic factor (BDNF) mRNA were greater in mHFD compared with mCD rabbits and mCD10d rabbits. In conclusion, the higher MAP in mHFD and mCD10d offspring was likely due to greater central leptin signaling at distinct sites within the hypothalamus while enhanced melanocortin contribution was common to both groups suggesting that residual body fat was mainly responsible. However, the effects of SHU9119 and αMSH on RSNA pathways only in mHFD suggest a maternal HFD may program sympatho-excitatory capacity in these offspring and that this may involve increased leptin receptor and BDNF expression.

Podocyte endowment and the impact of adult body size on kidney health.

Low birth weight is a risk factor for chronic kidney disease, whereas adult podocyte depletion is a key event in the pathogenesis of glomerulosclerosis. However, whether low birth weight due to poor maternal nutrition is associated with low podocyte endowment and glomerulosclerosis in later life is not known. Female Sprague-Dawley rats were fed a normal-protein diet (NPD; 20%) or low-protein diet (LPD; 8%), to induce low birth weight, from 3 wk before mating until postnatal day 21 (PN21), when kidneys from some male offspring were taken for quantitation of podocyte number and density in whole glomeruli using immunolabeling, tissue clearing, and confocal microscopy. The remaining offspring were fed a normal- or high-fat diet until 6 mo to induce catch-up growth and excessive weight gain, respectively. At PN21, podocyte number per glomerulus was 15% lower in low birth weight (LPD) than normal birth weight (NPD) offspring, with this deficit greater in outer glomeruli. Surprisingly, podocyte number in LPD offspring increased in outer glomeruli between PN21 and 6 mo, although an overall 9% podocyte deficit persisted. Postnatal fat feeding to LPD offspring did not alter podometric indexes or result in glomerular pathology at 6 mo, whereas fat feeding in NPD offspring was associated with far greater body and fat mass as well as podocyte loss, reduced podocyte density, albuminuria, and glomerulosclerosis. This is the first report that maternal diet can influence podocyte endowment. Our findings provide new insights into the impact of low birth weight, podocyte endowment, and postnatal weight on podometrics and kidney health in adulthood.NEW & NOTEWORTHY The present study shows, for the first time, that low birth weight as a result of maternal nutrition is associated with low podocyte endowment. However, a mild podocyte deficit at birth did not result in glomerular pathology in adulthood. In contrast, postnatal podocyte loss in combination with excessive body weight led to albuminuria and glomerulosclerosis. Taken together, these findings provide new insights into the associations between birth weight, podocyte indexes, postnatal weight, and glomerular pathology.

Impact of in vitro embryo culture and transfer on blood pressure regulation in the adolescent lamb.

Nutrition during the periconceptional period influences postnatal cardiovascular health. We determined whether in vitro embryo culture and transfer, which are manipulations of the nutritional environment during the periconceptional period, dysregulate postnatal blood pressure and blood pressure regulatory mechanisms. Embryos were either transferred to an intermediate recipient ewe (ET) or cultured in vitro in the absence (IVC) or presence of human serum (IVCHS) and a methyl donor (IVCHS+M) for 6 days. Basal blood pressure was recorded at 19-20 weeks after birth. Mean arterial pressure (MAP) and heart rate (HR) were measured before and after varying doses of phenylephrine (PE). mRNA expression of signaling molecules involved in blood pressure regulation was measured in the renal artery. Basal MAP did not differ between groups. Baroreflex sensitivity, set point, and upper plateau were also maintained in all groups after PE stimulation. Adrenergic receptors alpha-1A (αAR1A), alpha-1B (αAR1B), and angiotensin II receptor type 1 (AT1R) mRNA expression were not different from controls in the renal artery. These results suggest there is no programmed effect of ET or IVC on basal blood pressure or the baroreflex control mechanisms in adolescence, but future studies are required to determine the impact of ET and IVC on these mechanisms later in the life course when developmental programming effects may be unmasked by age.