PURPOSE: Previous studies have reported an increased prevalence of ocular diseases in patients with obstructive sleep apnea. The purpose of this study was to examine the link between such ocular diseases as diabetic retinopathy, diabetic macular edema, retinal vein occlusion, central serous chorioretinopathy, age-related macular degeneration, non-arteritic anterior ischemic optic neuropathy, and glaucoma. METHODS: This meta-analysis was conducted through a search using PubMed, Web of Science, Scopus and EMBASE. We identified both retrospective and prospective studies. RESULTS: The final meta-analysis looked at 30 studies and 7 ocular diseases. The data showed a high prevalence of obstructive sleep apnea for diabetic retinopathy and diabetic macular edema patients. Data for glaucoma and non-arteritic anterior ischemic optic neuropathy patients did not show a statistical increase. There was not enough data for retinal vein occlusion, central serous chorioretinopathy and age-related macular degeneration to calculate statistical significance. CONCLUSION: These data suggests that patient populations with diabetic retinopathy and macular edema show increased rates of obstructive sleep apnea. Data suggest that hypoxia is an important part of the pathophysiology of diabetic retinopathy and diabetic macular edema. Because obstructive sleep apnea has been shown to affect the progression of the ocular diseases included in this study, ophthalmologists should screen for the presence of obstructive sleep apnea to better help their patients. / 2021-06-14T00:00:00Z

No description available.

Diabetic retinopathy (DR) is an incurable, chronic disease that is the leading cause of blindness in working-age adults. A prominent characteristic of DR is the extensive dysfunction within the retina microvasculature. Specialized vascular cells known as pericytes (PCs) are lost or become dysfunctional during disease progression; a thickening of the extracellular matrix (ECM) composing the vascular basement membrane (vBM) and endothelial cell (EC) tight junction disruption are also key features of this disease and contribute to its pathogenesis. PC loss is believed to be a central cue for disease initiation. However, studies inducing PC loss and observing acute changes in the vasculature did not report severe vessel damage or vBM thickening, suggesting that the effects of PC loss occur over a longer period of time. Because the chronic effects of PC loss are more difficult to ascertain, especially in a complex condition such as DR, the mechanisms underlying microvascular defects in DR remain poorly understood. The work presented in this dissertation focuses on pericyte-endothelial cell interactions and their interplay with the ECM/vBM during a variety of physiological and pathological conditions. First, we isolated and functionally validated a primary mouse embryonic PC cell line that we then applied to a co-culture model with ECs to better understand the dynamic interactions between these two critical components of the capillary wall. In the co-culture model, we found that primary PCs promoted EC organization into vessel-like structures and enhanced EC-EC junctions. To complement these in vitro studies, we analyzed animal models and human tissue for the PC-EC interactions and ECM/vBM remodeling under different conditions (physiological and pathological). Moreover, we analyzed microglia and astrocytes to enhance our understanding of the tissue-vessel interface, bolstering our experimental results and facilitating the generation of more hypotheses for future research. Overall, our work suggests that PC-EC interactions in diabetic scenarios play a crucial role in ECM/vBM remodeling; engagement with the ECM/vBM in turn impacted PC behaviors including migration away from the endothelium and induced EC loss of tight junctions, key changes in the onset and progression of DR. / Doctor of Philosophy / Diabetic retinopathy is a group of eye diseases occurring in patients suffering from diabetes and is the leading cause of adult blindness among the working-aged. About one in three people with diabetes over the age of 40 have overt signs of DR. The primary cause for this disease is long-term, high blood sugar levels that damages blood vessels systemically as well as in the eye. Current treatments for DR can prevent the condition from getting worse, but no treatment exists that results in a complete cure. This work described in this dissertation focuses on the interactions between vascular pericytes and endothelial cells, two of the main cell types that compose capillaries (i.e. the smallest blood vessels important for oxygen delivery). The studies presented herein also focus on the response of these cells to the extracellular matrix, a scaffold of proteins that surround pericytes and endothelial cells to stabilize blood vessels. We found that extracellular matrix components dramatically increase as a result of the interactions between pericytes and endothelial cells exposed to diabetic conditions. These changes in the extracellular matrix also had important effects on pericytes and endothelial cells and their engagement with their environment and other cells. Taken together, our work suggests that pericyte-endothelial cell interactions and their crosstalk with the ECM play an important role in blood vessel formation and in the accumulation of microvascular defects that fuel diabetic retinopathy progression.

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy

Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1571. Adviser: Craig L. Hanis. Includes bibliographical references.

Magister Public Health - MPH / BACKGROUND AND RATIONALE: The Cape Town Metro District Health Service (MDHS) has introduced a Diabetic RetinopathyScreening (DRS) programme incorporating retinal fundal photography in diabetic services at primary health care (PHC) facilities. Hitherto, coverage of the DRS programme has been less than optimal in part due to volumes of diabetic patients attending PHC facilities. The aim of this study was to identify possible sub-groups of patients, attending the Cape Town DRS Programme, who are at most risk of diabetic retinopathy and might be prioritised for early diabetic retinopathy detection and subsequent sight-saving treatment. METHODOLOGY: A case-control study of risk factors for treatment-requiring diabetic retinopathy was conducted. This research sampled participants from the DRS programme provided by the MDHS eye care team to Type II diabetics attending public PHC facilities within the Klipfontein and Mitchells Plain Sub-Districts. Based on fundal images, cases were selected as those requiring ophthalmological treatment; and controls (three matched per case by area of residence) as those judged as not requiring ophthalmological treatment for diabetic retinopathy. Data on possible risk factors (clinical, laboratory) were extracted from the patients' folders. RESULT: The study included 453 participants, of whom 113 (24.9%) were cases and 340 (75.1%) were controls. Three factors were significantly associated with treatment-requiring diabetic retinopathy on multivariate analysis: Insulin dependency (OR of 2.96, 95% CI: 1.75 – 5.00); duration of diabetes of more than 10 years (OR of 3.44, 95% CI: 2.06 – 5.74) and sustained hyperglycaemia over the past six months (OR of 3.73, 95% CI: 1.69 – 8.22). A screening algorithm combining these criteria had a sensitivity of 61.2% (95% CI: 51.9 – 70.5). CONCLUSION: The findings indicate that a sub-set of patients attending the DRS programme in the Klipfontein and Mitchells Plain Sub-Districts have a greater likelihood of presenting with treatment-requiring diabetic retinopathy. Further research is required to develop a tool that is sufficiently sensitive to safely prioritise patients for fundal screening. / National Research Foundation (NRF)

Thesis (MPH.) -- University of Limpopo, 2021 / Background: Diabetes mellitus (DM) is a major public health problem, and it remains one of the global epidemics of non-communicable diseases. Diabetic retinopathy (DR) is a micro-vascular complication of DM due to a prolonged hyperglycaemia, and it is the most common cause of a visual loss in people living with DM. The global increase in the prevalence of DM has led to an increase in prevalence of diabetic complications, such as DR. The primary aim of this study was to investigate the prevalence and determinants of DR among the DM patients receiving treatment from Maruleng public healthcare facilities, Mopani District in the Limpopo Province. Methodology: A quantitative cross-sectional survey was used as a primary source data from the DM patients who were readily available at the selected public healthcare facilities to collect a chronic treatment during the time of the study. Selection of eligible DM patients was done through a convenient sampling technique for those who were readily available or willing to take part of the study after receiving all information about the study for them to consent freely without any form of coercion by researcher or any other person. All selected respondents had undergone face-to-face interviews and basic clinical screening for DR to collect a primary source data using piloted structured researcher-administered questionnaire to record data collected from respondents, and calibrated medical equipment were used to measure a clinical variables during clinical screening. Data analysis was carried out using Statistics and Data Analysis (STATA) version 15 software for windows. The characteristics of DM patients were summarised and analysed using a descriptive statistics. Inferential statistics were performed on dependent variable and independent variables using a logistic regression analysis to determine the strength of association between variables, where a potential predictors of DR among DM patients were identified at significant level of less than 0.05 (p<0.05). Results: Out of the 416 DM patients who participated in the study, the majority were females (n=315; 76%) and all DM patients were above the age of 18 years, with a mean age of 61 years (standard deviation [SD] =11.5). The overall prevalence of DR was 35.4% comprising 32% mild non-proliferative DR (NPDR) and 3.4% moderate NPDR. DR was found to be slightly more prevalent in females, at 35.9%, than in males, at 34.6%; particularly in those females with type 2 DM, at 35.1%, comprising 32.1% mild NPDR and 3% moderate NPDR. DR was more prevalent in older females, at 77.8%, comprising 55.6% mild NPDR and 22.2% moderate NPDR. The DM patients aged 55 years and above were found to be 2.7 times more likely to develop DR, at p<0.001, and DM patients with higher systolic blood pressure of 140 mmHg or more were found to be 1.4 times more likely to develop DR as compared to DM patients with a systolic blood pressure of 139 mmHg or less (≤139 mmHg), at p<0.05. Employed DM patients were 1.4 times more likely to develop DR as compared to unemployed DM patients, at p<0.001. Age of the DM patients, high systolic blood pressure (SBP) or a hypertension of 140 mmHg or more (≥ 140 mmHg), and employment status were significantly associated with higher risk of developing DR among DM patients. Gender, hyperglycaemic state, poor glycaemic control, smoking and high BMI were found to be associated with DR but this association was not statistically significant. Conclusion and recommendations: Slightly more than one third of the DM patients receiving treatment during the study period from the public healthcare facilities in the Maruleng sub-district had some form of DR, which means that nearly four in ten DM patients had some form of DR. Diabetic retinopathy was more prevalent in females, and in older DM patients. Age of the DM patient, employment status, and high systolic blood pressure were significantly associated with an increased risk of developing DR among the DM patients. There is an urgent need to implement a health promotional programmes to educate people about the complications of a diabetes mellitus such as DR, and also to establish a coordinated screening programme for DR among DM patients receiving a chronic treatment, which must be supported by the Department of Health in all public healthcare facilities. Keywords: Diabetes Mellitus, Diabetic Retinopathy, Prevalence, Determinants / Health and Welfare Sector Education and Training Authority (HWSETA)

Approved for public release; distribution is unlimited / The connection between eye disease and diabetes is proven and is no longer a point of conjecture. In focusing attention on the retina, profound inroads have been made in the fight against this dreaded disorder of the blood. By carefully imaging the blood vessels in the eye, medical professionals can make accurate diagnoses based upon the changes and abnormalities observed. In addition, because the vasculature in the retina is extremely sensitive to fluctuations in normal bodily processes, often the first indication of diabetes and many other diseases manifest themselves here and are found during routine eye examinations. This thesis will explore the possibilities of a new method of retinal imaging by the blending and application of existing technologies. With the use of an automated, infrared-based imaging system, problems related to human error and the limitations of existing methods can be readily resolved and the groundwork can be laid for a new standard of accuracy in retinal imaging. Most importantly, it will automate the entire procedure providing medical specialists heretofore unavailable accuracy in their diagnoses. / http://archive.org/details/functionalspecif00domb / Lieutenant, United States Navy

This thesis reports an investigation from the “bedside” back to the “bench”. That is, from the economic evaluation of a medical intervention to basic research and development of a contractility assay. The underlying theme of this thesis is cellular contractility, which was stimulated from our laboratory’s work in the microvascular complications of Diabetic Retinopathy (DR). The health economic perspective of this thesis evaluates the cost effectiveness and cost utility of DR prognosis using the prog-DR test. This novel prognostic test developed in our laboratory relies on the contractile response of blood vessels to detect subjects with high risk of developing DR. Markov modeling based on information in the literature was used to estimate the outcomes of a hypothetical population. The costs, health and utility outcomes of DR were compared to the potential outcomes if the prog-DR test was used. The model show that the prog-DR test can improve the health of the hypothetical population as measured in the number of life years (LY), sight years (SY) and quality-adjusted life years (QALY). The prog-DR test was more cost effective than the benchmark of annual or bi-annual screening and the incremental cost effectiveness ratio (ICER) appears to be at an acceptable level. Scenario and sensitivity analysis also show that the cost effectiveness of the prog-DR test can be improved by (i) better blood glucose management post prog-DR test, (ii) targeted screening (as opposed to population-wide screening) and (iii) reduced costs of both screening and management of DM and DR. The physiological perspective of the thesis aimed to develop a contractility assay for DR that was based on a 3D scaffold, which was affordable, easy to make and mimicked the three dimensional physiological environment of blood vessels. The contractility assay was developed using a 3D, hollow scaffold (PE-PAH capsule) and involved (i) the selection of the optimal core material, (ii) optimisation of the manufacturing process, (iii) characterisation of the scaffold and (iv) ensuring that cells can be grown on it. The cyto-biocompatibility of the candidate polyelectrolyte Poly(Sodium 4-Styrene Sulfonate) (PSS) and Poly(Allylamine Hydrochloride) (PAH) in the thin films format were investigated using three different cell lines and the effects of these thin films were also compared to titanium and titanium nitride thin films. In essence, PSS and PAH are not cytotoxic and was used to develop the contractile scaffold, PE-PAH capsule. This scaffold is relative elastic and the contractile force exerted by the 3T3-L1 cells was calculated based on the deformation of the PE-PAH capsule. The contractility assay was sufficiently sensitive to detect the nano-Newton magnitude of force developed by individual cells and discriminated the change in force due to disruption of the F-actin cytoskeleton by forskolin and cytochalasin D.

Thesis (M.A.S.), Memorial University of Newfoundland, 2000. / Bibliography: leaves 70-71.