Postmortem Ultrastructural Analysis of the Retina from COVID-19 Deceased Patients.

PURPOSE: COVID-19 (coronavirus disease 2019) is an infectious disease caused by SARS-CoV-2, first reported in 2019 in Wuhan, China. Among the common complications is a pro-inflammatory and hypercoagulative response that compromises the vasculature among various organs. METHODS: In this report, we present the postmortem retinal findings of five patients observed by means of optical microscopy and transmission and scanning electron microscopy techniques. RESULTS: Clinical manifestations such as retinal hemorrhages and exacerbated inflammatory infiltrate, altered ultra structure with swollen mitochondria and pyknotic cells in both layers of the retina were observed in all analyzed eyes. CONCLUSION: Our data point to the fragility of this tissue in cases of severe COVID-19.

SGLT2 Inhibition with Empagliflozin as a Possible Therapeutic Option for Postprandial Hypoglycemia After Bariatric Surgery.

PURPOSE: Since SGLT2 inhibitors may reduce postprandial hyperglycemia, this study aimed to evaluated whether empagliflozin might be useful in the treatment of postprandial hypoglycemia (PPH) postbariatric surgery (BS). PATIENTS AND METHODS: Fourteen patients who underwent BS, nine without type 2 diabetes and five with diabetes before surgery and in remission after surgery, were included. Seven of them presented symptoms of PPH (hypoglycemic group; HG) and seven were asymptomatic (nonhypoglycemic group (NHG)). A meal tolerance test was performed before and after administration of a daily dose of empagliflozin (EMPA) 25 mg for 3 days. Plasma glucose and serum insulin levels were measured. RESULTS: In HG, compared with NHG, in the basal test, the area under the curve (AUC) of plasma glucose levels (AUCgly) was smaller (158.3 ± 25.3 vs 276.6 ± 79.2 mg h dL-1; p = 0.001) while the AUC of insulin levels (AUCins) did not differ, leading to a higher AUCins/AUCgly ratio (0.79 ± 0.46 vs 0.38 ± 0.20; p = 0.055) and a lower HOMA-IR (0.92 ± 0.22 vs 1.75 ± 0.77; p = 0.030). The HG after EMPA, but not the NHG, showed significant increases in glycemia leading to greater AUCgly (158.0 ± 25.3 to 197.2 ± 51.6 mg h dL-1; p = 0.043) without significant changes in AUCins. HOMA-IR increased only in the HG (0.92 ± 0.20 vs 1.61 ± 0.30; p = 0.025) and, when both groups were analyzed together, both before and post EMPA, a significant correlation was found between HOMA-IR and AUCgly values (r = 0.594; p = 0.002). CONCLUSION: Our results suggest that empagliflozin increased glycemic levels in patients with PPH possibly through increases in hepatic glucose production.

Retinal autofluorescence findings after COVID-19.

The main purpose of this study was to investigate the presence of retinal autofluorescence findings in COVID-19 patients. Observational study conducted in São Paulo in 2020. Demographic, medical history, and concomitant events, as well as medications used, hospitalization details, and laboratory test results, were obtained. Patients underwent eye examination and multimodal imaging, including color, red-free, autofluorescence fundus photography and optical coherence tomography. Eighteen patients had autofluorescence findings (6 females; average age 54 years, range 31 to 86 years; 26 eyes). Hyper-autofluorescence findings were present in 6 patients, Hypo-autofluorescence in 14 patients, and 6 patients had mixed pattern lesions. Retinal autofluorescence abnormalities were present in COVID-19 patients and may be secondary to primary or secondary changes caused by the SARS-CoV-2.

COVID-19 Retinal Findings in Patients Admitted to Intensive Care Units and Wards.

The main purpose of this study was to investigate ocular clinical findings in patients with confirmed COVID-19 infection, of various levels of disease severity, who required mechanical ventilation and admission to intensive care units or specialized wards. Longitudinal, observational study conducted from March 2020 to June 2020. Color fundus and red-free photography were performed in both eyes following pupillary dilation. 104 participants were recruited from 2 different centers: 60 (58%) from the Hospital Municipal de Barueri intensive care unit (ICU) and 44 (42%) from specialized wards for patients with COVID-19 at the Hospital São Paulo. 21.9% presented with eye lesions, in 3% these lesions were vision compromising. Our results have shown similar rate of intraocular lesions in patients in both the ward or intensive care unit, regardless of medication use, including anticoagulant drugs.

[Major histocompatibility complex (MHC) class II: are lipid rafts the missing link?]. / Complexe majeur d'histocompatibilité de classe II : diversité fonctionnelle.

Aside from their crucial roles in the presentation of nominal antigen to CD4+ T cells and susceptibility to autoimmune diseases, substantial evidences suggest that MHC class II molecules act as signal transducer receptors as well. The signals transmitted affect diverse biological functions. Paradoxically, the cytoplasmic and transmembrane domains of these molecules are devoid of classic signaling motifs. The recent discovery of the presence of membrane microdomains, also called lipid rafts, that are enriched in kinases and adaptor molecules, may contribute to the elucidation of the mechanisms by which MHC class II molecules transmit their signals.

CD154 and its receptors in inflammatory vascular pathologies.

CD154, a member of the tumor necrosis factor-alpha family, has recently been implicated in the pathophysiology of vascular diseases. Indeed, blockade of CD154 by neutralizing antibodies or genetic disruption in mice prevents atherosclerosis and atherothrombosis. CD154 is believed to interact mainly via the CD40 receptor, however, it has also been found to bind with alphaIIbbeta3 integrin and so induces platelet activation. Moreover, we (and others) have recently identified the integrins alpha5beta1 and Mac-1 as novel CD154 receptors expressed on many cell types. Here, we illustrate the various functional features of these molecules, while describing the increasingly important role of CD40 in CD154-associated vascular pathologies such as atherosclerosis and atherothrombosis.