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The nephron segments in the inner medulla are part of the urine concentrating mechanism. Depending on the diuretic state, they are facing a large range of extracellular osmolality. We investigated whether water homeostasis affects tubular transport and permeability properties in inner medullary descending thin limb (IMdTL) and ascending thin limb (IMaTL). Three experimental groups of rats under different diuretic states were investigated on metabolic cages: waterload, furosemide-induced diuresis, and control (antidiuresis). Urine production and osmolalities reflected the 3-day treatment. To functionally investigate tubular epithelial properties, we performed experiments in freshly isolated inner medullary thin limbs from these animals. Tubular segments were acutely dissected and investigated for trans- and paracellular properties by in vitro perfusion and electrophysiological analysis. IMdTL and IMaTL were distinguished by morphological criteria. We confirmed absence of transepithelial electrogenic transport in thin limbs. Although diffusion potential measurements showed no differences between treatments in IMdTLs, we observed increased paracellular cation selectivity under waterload in IMaTLs. NaCl diffusion potential was -5.64 ± 1.93 mV under waterload, -1.99 ± 1.72 mV under furosemide-induced diuresis, and 0.27 ± 0.40 mV under control. The corresponding permeability ratio PNa/Cl was 1.53 ± 0.21 (waterload), 1.22 ± 0.18 (furosemide-induced diuresis), and 0.99 ± 0.02 (control), respectively. Claudins are main constituents of the tight junction responsible for paracellular selectivity; however, immunofluorescence did not show qualitative differences in claudin 4, 10, and 16 localization. Our results show that IMaTLs change tight junction properties in response to diuretic state to allow adaptation of NaCl reabsorption. [ABSTRACT FROM AUTHOR]

Background: Microinvasive procedures have become established in glaucoma surgery and are preferred for patients with target pressure values that are not too low. Excimer laser trabeculotomy (ELT) represents such a minimally invasive approach and can easily be combined with cataract surgery., Objective: Over 12 months the reduction in intraocular pressure (IOP), the number of antiglaucoma drugs and the incidence of adverse events were evaluated using the new Elios TM method (Elios Vision GmbH, Germering, Germany) for real-life data from a heterogeneous patient population undergoing ELT in combination with cataract surgery (phaco-ELT)., Material and Methods: In this study 20 eyes of 13 patients who underwent phaco-ELT were retrospectively analyzed. After standard phacoemulsification with posterior chamber lens implantation, 10 microchannels were created using the excimer laser. The patients were followed for 12 months and the intraocular pressure (IOP), number of antiglaucoma drugs and the occurrence of adverse events were analyzed., Results: The average age was 65 years. The preoperative IOP was 17.5 (± 5.3) mm Hg. The mean IOP reduction was 4.8 mm Hg (27.4%, p < 0.001) on the first postoperative day, 3.2 mm Hg (18.3%, p = 0.22) after 6 months and 2.5 mm Hg (14.3%, p = 0.14) at 12 months. The number of antiglaucoma drugs decreased from an average of 3.2 (± 1.3) preoperatively to 0.5 (± 0.9) on day 1 (p < 0.001), 1.9 (± 1.2) after 6 months (p = 0.008) and 2.2 (± 1.3) after 12 months (p = 0.013)., Discussion: In our cohort ELT in combination with cataract surgery is a safe minimally invasive procedure leading to an IOP reduction of 14.3% and a reduction of pressure-lowering medication by 1 active ingredient in patients with low initial pressure at 1‑year follow-up. As no implant is used in ELT and the conjunctiva remains untouched, subsequent procedures, including bleb-related surgery, are not negatively affected., (© 2024. The Author(s).)

Background: Intraocular metastases arising from solid tumors are found in approximately 2% of patients with metastatic tumor diseases and are therefore more frequent than originally assumed. They often affect the uvea and are associated with a poor prognosis. Due to the difficult diagnosis and an inconsistent treatment regimen, ophthalmologists have a special responsibility here., Objective: This article gives a summary of the various types of intraocular metastases with respect to clinical features, diagnostics, treatment and prognosis as well as recommendations for follow-up care., Methods: A selective literature search was carried out on the topic of intraocular metastases using PubMed and Google Scholar., Results: Intraocular metastases most frequently affect the uvea, specifically the choroid. In most cases the underlying disease is breast or lung cancer, but other rarer primary tumors have also been reported in the literature. Metastatic lesions can show very different morphological manifestations but can be distinguished based on the corresponding structure of manifestation in the eye and with the aid of targeted staging, thus providing valid information on the type of primary tumor. The treatment is partly experimental and usually depends on the primary tumor and leading symptoms of the patient. A differentiation between a curative or palliative treatment situation must always be made., Conclusion: Intraocular metastases are the most frequent intraocular tumor and are usually associated with a poor prognosis. Accurate diagnostics for finding the treatment as well as interdisciplinary collaboration and the presentation of the patient on the tumor board are essential., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Purpose: To investigate fluorescence lifetime of mouse models of age-related macular degeneration (AMD) by fluorescence lifetime imaging ophthalmoscopy (FLIO)., Methods: Two AMD mouse models, apolipoprotein E knockout (ApoE-/-) mice and NF-E2-related factor-2 knockout (Nrf2-/-) mice, and their wild-type mice underwent monthly ophthalmic examinations including FLIO from 3 months of age. After euthanasia at the age of 6 or 11 months, blood plasma was collected to determine total antioxidant capacity and eyes were enucleated for Oil red O (ORO) lipid staining of chorioretinal tissue., Results: In FLIO, the mean fluorescence lifetime (τm) of wild type shortened with age in both spectral channels. In short spectral channel, τm shortening was observed in both AMD models as well, but its rate was more pronounced in ApoE-/- mice and significantly different from the other strains as months of age progressed. In contrast, in long spectral channel, both model strains showed completely opposite trends, with τm becoming shorter in ApoE-/- and longer in Nrf2-/- mice than the others. Oil red O staining at Bruch's membrane was significantly stronger in ApoE-/- mice at 11 months than the other strains. Plasma total antioxidant capacity was highest in ApoE-/- mice at both 6 and 11 months., Conclusions: The two AMD mouse models exhibited largely different fundus fluorescence lifetime, which might be related to the different systemic metabolic state. FLIO might be able to indicate different metabolic states of eyes at risk for AMD., Translational Relevance: This animal study may provide new insights into the relationship between early AMD-associated metabolic changes and FLIO findings.