Effects of water chestnut (Tarpa bispinosa Roxb.) extract/lutein on fingertip-measured advanced glycation endproduct/carotenoid levels.

This pilot study tested the effects of the supplements containing water chestnut extract and carotenoids on antiglycation and carotenoid levels. Twenty Japanese subjects (mean age, 67 ± 7 years; 13 men) ingested 200 mg of Tarpa bispinosa Roxb. extract (containing >50 mg of polyphenols), 20 mg of lutein, and 3 mg of zeaxanthin daily for 3 months. Advanced glycation end product (AGEs) levels were estimated by fingertip skin autofluorescence using the AGEs Sensor; carotenoid levels were estimated by pressure-mediated reflection spectroscopy of the fingertips using the Veggie Meter. Compared to baseline, the mean AGEs score decreased significantly (0.55 ± 0.04 arbitrary units (AU) vs. 0.52 ± 0.07 AU, p = 0.03); the mean carotenoid score increased significantly (256 ± 68 optical density (OD) vs. 302 ± 109 OD, p = 0.02) at 3 months. Blood pressure, body weight, visual acuity, refractive error, and intraocular pressure were equivalent between baseline and 3 months. Compared to baseline, 13 (65%) patients had decreased AGEs scores, and 14 (70%) had increased carotenoid scores at 3 months; 9 (45%) subjects had both decreased AGEs scores and increased carotenoid scores, and two (10%) subjects had an inverse response. Co-administration of water chestnut extract and lutein for 3 months decreased the AGEs and increased the carotenoids estimated in the fingertip skin of humans.

Bilateral Optic Disc Swelling with Preserved Visual Function Associated with Giant Cell Arteritis.

A 68-year-old Japanese man was introduced to our hospital for optic disc swelling (ODS) in his both eyes (OU). Other than floaters in his right eye, he did not report any symptoms including blurred vision, visual field defect, and ocular pain. Light reflex was prompt and complete OU, and critical flicker frequency was within the normal range OU. By fluorescein angiography, hyperfluorescence was detected on optic discs OU; however, no fluorescein leakage or filling defect was observed. By Goldmann perimetry, enlargement of the Mariotte blind spot was revealed OU, while no central scotoma or remarkable visual field defects were detected. By neuroimaging and lumbar puncture, papilledema due to intracranial pressure elevation was denied. Based on the reassessment of fundus findings, narrowing and segmental whitening/sheathing of peripapillary vessels predominantly to arterioles were realized, and systemic arteritis was suspected. Based on the subject age, elevation of erythrocyte sedimentation rate, positron emission tomography findings in the aorta, and MRI findings in temporal arteries, underlying giant cell arteritis (GCA) was diagnosed. After the start of systemic and local steroid therapies, ODS improved OU. Although rare, bilateral ODS with no visual disturbance can occur in patients with GCA. This case emphasizes the importance of careful assessment of ocular findings to reach the correct diagnosis of even a rare cause of ODS.

Conjunctival Chemosis and Annular Ciliochoroidal Detachments Detected by Anterior-Segment Optical Coherence Tomography in a Case of Systemic Lupus Erythematosus.

A 61-year-old Japanese woman presented to our hospital for treatment of systemic serositis associated with systemic lupus erythematosus (SLE). At the initial ophthalmologic examination, her best-corrected visual acuity was 1.2 and 0.6 in her right and left eyes, respectively. Slit-lamp examination showed marked chemosis in both eyes (OU). Swept source-based, anterior-segment optical coherence tomography (AS-OCT) clearly showed conjunctival elevations corresponding to the chemosis in all scan directions OU. In some scans, hyporeflective spaces with luminal structures corresponding to dilated lymphatic channels and nonluminal structures corresponding to interstitial fluid accumulation were seen clearly under the conjunctival epithelium and/or in the parenchyma. In all scan directions, the supraciliary space was seen clearly, suggesting the presence of an annular ciliochoroidal detachment. Fundus examinations showed retinal edema temporal to the optic nerve head and subfoveal serous retinal detachments OU. Ocular effusions resolved by 2 weeks after the start of steroid pulse therapy, and pleural effusions and ascites resolved and pericardial effusion decreased by 2 months. AS-OCT can be useful for understanding the mechanism(s) of the less common anterior-segment ocular manifestations of SLE.

Orm protein phosphoregulation mediates transient sphingolipid biosynthesis response to heat stress via the Pkh-Ypk and Cdc55-PP2A pathways.

Sphingoid intermediates accumulate in response to a variety of stresses, including heat, and trigger cellular responses. However, the mechanism by which stress affects sphingolipid biosynthesis has yet to be identified. Recent studies in yeast suggest that sphingolipid biosynthesis is regulated through phosphorylation of the Orm proteins, which in humans are potential risk factors for childhood asthma. Here we demonstrate that Orm phosphorylation status is highly responsive to sphingoid bases. We also demonstrate, by monitoring temporal changes in Orm phosphorylation and sphingoid base production in cells inhibited for yeast protein kinase 1 (Ypk1) activity, that Ypk1 transmits heat stress signals to the sphingolipid biosynthesis pathway via Orm phosphorylation. Our data indicate that heat-induced sphingolipid biosynthesis in turn triggers Orm protein dephosphorylation, making the induction transient. We identified Cdc55-protein phosphatase 2A (PP2A) as a key phosphatase that counteracts Ypk1 activity in Orm-mediated sphingolipid biosynthesis regulation. In total, our study reveals a mechanism through which the conserved Pkh-Ypk kinase cascade and Cdc55-PP2A facilitate rapid, transient sphingolipid production in response to heat stress through Orm protein phosphoregulation. We propose that this mechanism serves as the basis for how Orm phosphoregulation controls sphingolipid biosynthesis in response to stress in a kinetically coupled manner.

Identification of Ypk1 as a novel selective substrate for nitrogen starvation-triggered proteolysis requiring autophagy system and endosomal sorting complex required for transport (ESCRT) machinery components.

Nitrogen starvation-mediated reduction of Ypk1 is suggested to suppress translational initiation, possibly in parallel with the target of rapamycin complex 1 (TORC1) signaling. However, the molecular mechanism that regulates Ypk1 in nitrogen-starved cells is poorly understood. Here we report that Ypk1 is a novel selective substrate for nitrogen starvation-triggered proteolysis requiring autophagy system. Among various nutrient starvation methods used to elicit autophagy, rapid Ypk1 degradation was specific to nitrogen starvation. In screening genes required for such nitrogen starvation-specific vacuolar proteolysis, we found that autophagy-related degradation of Ypk1 depended on the endosomal sorting complex required for transport (ESCRT) machinery, which is conventionally thought to function in endosomal trafficking. In microscopic analyses, the disruption of ESCRT subunits resulted in the accumulation of both Ypk1 and autophagosomal Atg8 at a perivacuolar site that was distinct from conventional endosomes. ESCRT machinery was not involved in autophagic flux induced by the TORC1 inhibitor rapamycin, thus suggesting that ESCRT represents an exclusive mechanism of nitrogen starvation-specific proteolysis of Ypk1. Overall, we propose a novel regulation of Ypk1 that is specific to nitrogen limitation.

Radixin deficiency causes conjugated hyperbilirubinemia with loss of Mrp2 from bile canalicular membranes.

The ezrin-radixin-moesin (ERM) family of proteins crosslink actin filaments and integral membrane proteins. Radixin (encoded by Rdx) is the dominant ERM protein in the liver of wildtype mice and is concentrated at bile canalicular membranes (BCMs). Here we show that Rdx(-/-) mice are normal at birth, but their serum concentrations of conjugated bilirubin begin to increase gradually around 4 weeks, and they show mild liver injury after 8 weeks. This phenotype is similar to human conjugated hyperbilirubinemia in Dubin-Johnson syndrome, which is caused by mutations in the multidrug resistance protein 2 (MRP2, gene symbol ABCC2), although this syndrome is not associated with overt liver injury. In wildtype mice, Mrp2 concentrates at BCMs to secrete conjugated bilirubin into bile. In the BCMs of Rdx(-/-) mice, Mrp2 is decreased compared with other BCM proteins such as dipeptidyl peptidase IV (CD26) and P-glycoproteins. In vitro binding studies show that radixin associates directly with the carboxy-terminal cytoplasmic domain of human MRP2. These findings indicate that radixin is required for secretion of conjugated bilirubin through its support of Mrp2 localization at BCMs.