Diabetic retinopathy screening with confocal fundus camera and artificial intelligence - assisted grading.

PURPOSE: Screening for diabetic retinopathy (DR) by ophthalmologists is costly and labour-intensive. Artificial Intelligence (AI) for automated DR detection could be a clinically and economically alternative. We assessed the performance of a confocal fundus imaging system (DRSplus, Centervue SpA), coupled with an AI algorithm (RetCAD, Thirona B.V.) in a real-world setting. METHODS: 45° non-mydriatic retinal images from 506 patients with diabetes were graded both by an ophthalmologist and by the AI algorithm, according to the International Clinical Diabetic Retinopathy severity scale. Less than moderate retinopathy (DR scores 0, 1) was defined as non-referable, while more severe stages were defined as referable retinopathy. The gradings were then compared both at eye-level and patient-level. Key metrics included sensitivity, specificity all measured with a 95% Confidence Interval. RESULTS: The percentage of ungradable eyes according to the AI was 2.58%. The performances of the AI algorithm for detecting referable DR were 97.18% sensitivity, 93.73% specificity at eye-level and 98.70% sensitivity and 91.06% specificity at patient-level. CONCLUSIONS: DRSplus paired with RetCAD represents a reliable DR screening solution in a real-world setting. The high sensitivity of the system ensures that almost all patients requiring medical attention for DR are referred to an ophthalmologist for further evaluation.

Feasibility and accuracy of the screening for diabetic retinopathy using a fundus camera and an artificial intelligence pre-evaluation application.

AIMS: Periodical screening for diabetic retinopathy (DR) by an ophthalmologist is expensive and demanding. Automated DR image evaluation with Artificial Intelligence tools may represent a clinical and cost-effective alternative for the detection of retinopathy. We aimed to evaluate the accuracy and reliability of a machine learning algorithm. METHODS: This was an observational diagnostic precision study that compared human grader classification with that of DAIRET®, an algorithm nested in an electronic medical record powered by Retmarker SA. Retinal images were taken from 637 consecutive patients attending a routine annual diabetic visit between June 2021 and February 2023. They were manually graded by an ophthalmologist following the International Clinical Diabetic Retinopathy Severity Scale and the results were compared with those of the AI responses. The main outcome measures were screening performance, such as sensitivity and specificity and diagnostic accuracy by 95% confidence intervals. RESULTS: The rate of cases classified as ungradable was 1.2%, a figure consistent with the literature. DAIRET® sensitivity in the detection of cases of referable DR (moderate and above, "sight-threatening" forms of retinopathy) was equal to 1 (100%). The specificity, that is the true negative rate of absence of DR, was 80 ± 0.04. CONCLUSIONS: DAIRET® achieved excellent sensitivity for referable retinopathy compared with that of human graders. This is undoubtedly the key finding of the study and translates into the certainty that no patient in need of the ophthalmologist is misdiagnosed as negative. It also had sufficient specificity to represent a cost-effective alternative to manual grade alone.

Ectopic secretion of LH by an endocrine pancreatic tumor.

Ectopic production of biologically active glycoprotein hormones other than hCG has been reported in exceptional cases. A 61-yr-old man came to our Unit complaining of weakness, fatigue and reduced libido with erectile dysfunction. There was also a history of polycythemia, known for about 10 yr and never further investigated. The physical examination showed acne and redness of facial skin and upper chest; no other significant abnormalities were detected. Serum levels of LH were very high, whereas alpha-subunit and hCG were only slightly increased. Testosterone and 17beta-estradiol levels were increased too. Abdominal computed tomography (CT) scan revealed a large hypervascularized mass within the pancreatic tail, which was surgically removed by distal splenopancreatectomy. Diffuse immunoreactivity for LH was detected in more than 70% of the tumor cells. The alpha-subunit was also positive, while chorionic gonadotropin had only a focal reactivity. Reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern Blot analysis confirmed the synthesis of LH by the tumor. Four weeks after surgery, serum levels of LH, alpha-subunit, testosterone, hCG and 17beta-estradiol were all undetectable. The redness of facial skin and upper chest had disappeared, but libido was still reduced. At a further control, 3 months after surgery, serum levels of LH, FSH, hCG, alpha-subunit and 17beta-estradiol were all within the normal range, as well as hemoglobin concentration and the red blood cells count. Testosterone was slightly below normal, but the patient reported an increase of libido. This is an unusual case of ectopic secretion of LH from an endocrine tumor of the pancreas.

Oxidative stress and eicosanoids in the kidneys of hyperglycemic rats treated with dehydroepiandrosterone.

Oxidative stress plays a crucial role in the pathogenesis of chronic diabetic complications. Normoglycemic and streptozotocin-diabetic rats were treated with dehydroepiandrosterone (DHEA) (4 mg/d per rat) for 3 weeks. At the end of treatment, hydroxynonenal, hydroperoxyeicosatetraenoic acids and antioxidant levels, as well as Na/K-ATPase activity and membrane fatty acids composition were evaluated in kidney homogenates. Chronic hyperglycemia caused a marked increase of both hydroxynonenal and lipoxygenase pathway products and a drop in both GSH levels and membrane Na/K-ATPase activity. DHEA treatment restored the antioxidant levels to close to the control value and considerably reduced hydroxynonenal and hydroperoxyeicosatetraenoic acid levels. Moreover, DHEA counteracted the detrimental effect of hyperglycemia on membrane function: the drop of Na/K-ATPase activity in diabetic animals was significantly inhibited by DHEA treatment. These results show that DHEA reduces oxidative stress and the consequent increase of lipoxygenase pathway products induced by experimental diabetes in rat kidney; they also suggest that, by reducing the inflammatory response to oxidative stress, DHEA treatment might delay the progression of diabetic kidney disease.

Dehydroepiandrosterone prevents oxidative injury induced by transient ischemia/reperfusion in the brain of diabetic rats.

Both chronic hyperglycemia and ischemia/reperfusion (IR) cause an imbalance in the oxidative state of tissues. Normoglycemic and streptozotocin (STZ)-diabetic rats were subjected to bilateral carotid artery occlusion for 30 min followed by reperfusion for 60 min. Rats had either been treated with dehydroepiandrosterone (DHEA) for 7, 14, or 21 days (2 or 4 mg/day per rat) or left untreated. Oxidative state, antioxidant balance, and membrane integrity were evaluated in isolated synaptosomes. IR increased the levels of reactive species and worsened the synaptic function, affecting membrane Na/K-ATPase activity and lactate dehydrogenase release in all rats. The oxidative imbalance was much severer when transient IR was induced in STZ-diabetic rats. DHEA treatment restored H2O2, hydroxyl radical, and reactive oxygen species to close to control levels in normoglycemic rats and significantly reduced the level of all reactive species in STZ-diabetic rats. Moreover, DHEA treatment counteracted the detrimental effect of IR on membrane integrity and function: the increase of lactate dehydrogenase release and the drop in Na/K-ATPase activity were significantly prevented in both normoglycemic and STZ-diabetic rats. The results confirm that DHEA, an adrenal steroid that is synthesized de novo by brain neurons and astrocytes, possesses a multitargeted antioxidant effect. They also show that DHEA treatment is effective in preventing both derangement of the oxidative state and neuronal damage induced by IR in experimental diabetes.

Dehydroepiandrosterone prevents lipid peroxidation and cell growth inhibition induced by high glucose concentration in cultured rat mesangial cells.

The oxidative stress induced by high glucose concentration contributes to tissue damage associated with diabetes, including renal injury. Dehydroepiandrosterone (DHEA), the major secretory product of the human adrenal gland, has been shown to possess a multi-targeted antioxidant activity which is also effective against lipid peroxidation induced by high glucose. In this study we evaluated the effect of DHEA on the growth impairment which high glucose concentration induces in cultured rat mesangial cells. Primary cultures of rat mesangial cells were grown for 10 days in media containing either normal (i.e. 5.6 mmol/l) or high (i.e. 30 mmol/l) concentrations of glucose, without or with DHEA at different concentrations. The impairment of cell growth induced by high glucose was reversed by 100 nmol/l and 500 nmol/l DHEA, which had no effect on mesangial cells cultured in media containing glucose at the normal physiological concentration (5.6 mmol/l). In high-glucose cultured mesangial cells, DHEA also attenuated the lipid peroxidation, as measured by thiobarbituric acid reactive substances (TBARS) generation and 4-hydroxynonenal (HNE) concentration, and preserved the cellular content of reduced glutathione as well as the membrane Na+/K+ ATPase activity. The data further support the protective effect of DHEA against oxidative damage induced by high glucose concentrations, and bring into focus its possible effectiveness in preventing chronic complications of diabetes.

Oxidative derangement in rat synaptosomes induced by hyperglycaemia: restorative effect of dehydroepiandrosterone treatment.

Central nervous system damage in diabetes is caused by both cerebral atherosclerosis and the detrimental effect of chronic hyperglycaemia on nervous tissue. Hyperglycaemia is the primer of a series of cascade reactions causing overproduction of free radicals. There is increasing evidence that these reactive molecules contribute to neuronal tissue damage. Dehydroepiandrosterone (DHEA) has been reported to possess antioxidant properties. This study evaluates the oxidative status in the synaptosomal fraction isolated from the brain of streptozotocin-treated rats and the antioxidant effect of DHEA treatment on diabetic rats. Hydroxyl radical generation, hydrogen peroxide content, and the level of the reactive oxygen species was increased (P<0.05) in synaptosomes isolated from streptozotocin-treated rats. The derangement of the oxidative status was confirmed by a low level of reduced glutathione and alpha-tocopherol. DHEA treatment (4 mg per day for 3 weeks, per os) protected the synaptosomes against oxidative damage: synaptosomes from diabetic DHEA-treated rats showed a significant decrease in reactive species (P<0.05) and in the formation of end products of lipid peroxidation, evaluated in terms of fluorescent chromolipid (P<0.01). Moreover, DHEA treatment restored the unsaturated fatty acid content of the membrane and the reduced glutathione and alpha-tocopherol levels to normal levels and restored membrane NaK-ATPase activity close to control levels. The results demonstrate that DHEA supplementation greatly reduces oxidative damage in synaptosomes isolated from diabetic rats and suggest that this neurosteroid may participate in protecting the integrity of synaptic membranes against hyperglycaemia-induced damage.

Protective effect of dehydroepiandrosterone against lipid peroxidation in a human liver cell line.

OBJECTIVE: Dehydroepiandrosterone (DHEA) is a widely studied steroid hormone with multi-functional properties. Reports suggest that some of the many activities of DHEA are due to its protective effect against lipid peroxidation. Nevertheless, the antioxidant properties of DHEA are still the subject of debate. The aim was to evaluate whether its two opposed effects on lipid peroxidation reported in the literature may be dependent on schedule and doses used. METHODS: Chang liver cells, a line derived from normal human liver, were grown in media containing either no steroids (control) or DHEA at concentrations ranging from 0.1 micromol/l to 50 micromol/l. At specific times, cultures were halted and cells received a pro-oxidant stimulus (cumene (CuOOH) 0.5 mmol/l), at which time cell viability (by trypan blue staining and lactate dehydrogenase (LDH) release) and thiobarbituric acid reactive substances (TBARS) concentration (spectrophotometrical assay) were evaluated. RESULTS: At concentrations ranging from 0.1 micromol/l to 1 micromol/l, DHEA protects Chang liver cells against lipid peroxidation and/or death induced by cumene. This effect disappears if the concentration is increased to 10 micromol/l; at higher concentrations (50 micromol/l) a pro-oxidant/cytotoxic effect of DHEA appears. CONCLUSIONS: DHEA exhibits two opposed effects on lipid peroxidation; depending on its concentration it acts either to limit or to induce oxidative stress. The threshold concentration at which the pro-oxidant activity of DHEA prevails is not far in excess of that having an antioxidant effect. Either effect of DHEA on lipid peroxidation is only evident after a 'lag-phase'.