Ninety percent of glucose filtered by the glomerulus is reabsorbed by a sodium-glucose cotransporter 2 (SGLT2), which is mainly expressed on S1 and S2 segment of renal proximal tubules. Since ...SGLT-2-mediated glucose reabsorption is increased under diabetic conditions, selective inhibition of SGLT2 is a potential therapeutic target for the treatment of diabetes. We have recently shown that an inhibitor of SGLT2 has anti-inflammatory and antifibrotic effects on experimental diabetic nephropathy partly by suppressing advanced glycation end products formation and oxidative stress generation in the kidney. However, the direct effects of SGLT2 inhibitor on tubular cell damage remain unclear. In this study, we investigated the effects of tofogliflozin, a highly selective inhibitor of SGLT2 on oxidative stress generation, inflammatory and proapoptotic reactions in cultured human proximal tubular cells exposed to high glucose. Tofogliflozin dose-dependently suppressed glucose entry into tubular cells. High glucose exposure (30 mM) for 4 and 24 h significantly increased oxidative stress generation in tubular cells, which were suppressed by the treatment of tofogliflozin or an antioxidant N-acetylcysteine (NAC). Monocyte chemoattractant protein-1 (MCP-1) gene expression and apoptotic cell death were induced by 4 h- and 8 day-exposure to high glucose, respectively, both of which were also blocked by tofogliflozin or NAC. The present study suggests that SGLT2-mediated glucose entry into tubular cells could stimulate oxidative stress and evoke inflammatory and proapoptotic reactions in this cell type. Blockade of glucose reabsorption in tubular cells by SGLT2 inhibitor might exert beneficial effects on tubulointerstitial damage in diabetic nephropathy.
Functional evaluation assays using human induced pluripotent stem cell (hiPSC)-derived neurons can predict the convulsion toxicity of new drugs and the neurological effects of antiepileptic drugs. ...However, differences in responsiveness depending on convulsant type and antiepileptic drugs, and an evaluation index capable of comparing in vitro responses with in vivo responses are not well known. We observed the difference in synchronized burst patterns in the epileptiform activities induced by pentylentetrazole (PTZ) and 4-aminopryridine (4-AP) with different action mechanisms using multi-electrode arrays (MEAs); we also observed that 100 µM of the antiepileptic drug phenytoin suppressed epileptiform activities induced by PTZ, but increased those induced by 4-AP. To compare in vitro results with in vivo convulsive responses, frequency analysis of below 250 Hz, excluding the spike component, was performed. The in vivo convulsive firing enhancement of the high γ wave and β wave component were observed remarkably in in vitro hiPSC-derived neurons with astrocytes in co-culture. MEA measurement of hiPSC-derived neurons in co-culture with astrocytes and our analysis methods, including frequency analysis, appear effective for predicting convulsion toxicity, side effects, and their mechanism of action as well as the comparison of convulsions induced in vivo.
Abstract
Screening for drug discovery targeting the central nervous system requires the establishment of efficient and highly accurate toxicity test methods that can reduce costs and time while ...maintaining high throughput using the function of an in vitro neural network. In particular, an evaluation system using a human-derived neural network is desirable in terms of species difference. Despite the attention, the microelectrode array (MEA) is attracting among the evaluation systems that can measure in vitro neural activity, an effective analysis method for evaluation of toxicity and mechanism of action has not yet been established. Here we established analytical parameters and multivariate analysis method capable of detecting seizure liability of drugs using MEA measurement of human iPS cell-derived neurons. Using the spike time series data of all drugs, we established periodicity as a new analytical parameter. Periodicity has facilitated the detection of responses to seizurogenic drugs, previously difficult to detect with conventional analytical parameters. By constructing a multivariate analytical method that identifies a parameter set that achieves an arbitrary condition, we found that the parameter set comprising total spikes, maximum frequency (MF), inter- MF interval (IMFI), coefficient of variance of IMFI, and periodicity can uniformly detect the seizure liability of seizurogenic drugs with different mechanisms of action. Seizurogenic drugs were suggested to increase the regularity of the network burst in MEA measurements in human iPS cell-derived neurons.
The reflectance spectra of the most abundant meteorites, ordinary chondrites, are different from those of the abundant S-type (mnemonic for siliceous) asteroids. This discrepancy has been thought to ...be due to space weathering, which is an alteration of the surfaces of airless bodies exposed to the space environment. Here we report evidence of space weathering on particles returned from the S-type asteroid 25143 Itokawa by the Hayabusa spacecraft. Surface modification was found in 5 out of 10 particles, which varies depending on mineral species. Sulfur-bearing Fe-rich nanoparticles exist in a thin (5 to 15 nanometers) surface layer on olivine, low-Ca pyroxene, and plagioclase, which is suggestive of vapor deposition. Sulfur-free Fe-rich nanoparticles exist deeper inside (<60 nanometers) ferromagnesian silicates. Their texture suggests formation by metamictization and in situ reduction of Fe2+.
Background/Objectives
Depression and hopelessness are frequently experienced in chronic kidney disease (CKD) and are generally associated with lessened physical activity. The aim of this study was to ...quantify the associations between sarcopenia as determined by SARC-F with both depression and hopelessness.
Design and Setting
This multicenter cohort study involving cross-sectional and longitudinal analyses was conducted in a university hospital and four general hospitals, each with a nephrology center, in Japan.
Participants
Participants consisted of 314 CKD patients (mean age 67.6), some of whom were receiving dialysis (228, 73%).
Measurements
The main exposures were depression, measured using the Center for Epidemiologic Studies Depression (CES-D) questionnaire, and hopelessness, measured using a recently developed 18-item health-related hope scale (HR-Hope). The outcomes were sarcopenia at baseline and one year after, measured using the SARC-F questionnaire. Logistic regression models were applied.
Results
The cross-sectional and longitudinal analyses included 314 and 180 patients, respectively. Eighty-nine (28.3%) patients experienced sarcopenia at baseline, and 44 (24.4%) had sarcopenia at the one-year follow-up. More hopelessness (per 10-point lower, adjusted odds ratio AOR: 1.33, 95% confidence interval 95% CI 1.12–1.58), depression (AOR: 1.87, 95% CI 1.003–3.49), age (per 10-year higher, AOR: 1.70, 95% CI 1.29–2.25), being female (AOR: 2.67, 95% CI 1.43–4.98), and undergoing hemodialysis (AOR, 2.92; 95% CI, 1.41–6.05) were associated with a higher likelihood of having baseline sarcopenia. More hopelessness (per 10-point lower, AOR: 1.69, 95% CI 1.14–2.51) and depression (AOR: 4.64, 95% CI: 1.33–16.2) were associated with a higher likelihood of having sarcopenia after one year.
Conclusions
Among patients with different stages of CKD, both hopelessness and depression predicted sarcopenia. Provision of antidepressant therapies or goal-oriented educational programs to alleviate depression or hopelessness can be useful options to prevent sarcopenia.
Methodical screening of safe and efficient drug candidate compounds is crucial for drug development. A high-throughput and accurate compound evaluation method targeting the central nervous system can ...be developed using in vitro neural networks. In particular, an evaluation system based on a human-derived neural network that can act as an alternative to animal experiments is desirable to avoid interspecific differences. A microelectrode array (MEA) is one such evaluation system, and can measure in vitro neural activity; however, studies on compound evaluation criteria and in vitro to in vivo extrapolation are scarce. In this study, we identified the parameters that can eliminate the effects of solvents from neural activity data obtained using MEA allow for accurate compound evaluation. Additionally, we resolved the issue associated with compound evaluation criteria during MEA using principal component analysis by considering the neuronal activity exceeding standard deviation (SD) of the solvent as indicator of seizurogenic potential. Overall, 10 seizurogenic compounds and three negative controls were assessed using MEA-based co-cultured human-induced pluripotent stem cell–derived neurons and astrocytes, and primary rat cortical neurons. In addition, we determined rat cerebrospinal fluid (CSF) concentrations during tremor and convulsion in response to exposure to test compounds. To characterize the in vitro to in vivo extrapolation and species differences, we compared the concentrations at which neuronal activity exceeding the SD range of the solvent was detectable using the MEA system and rat CSF concentration.
•Proposed prediction method for seizure liability based on in vitro MEA data in cultured neurons.•Verified correlations between in vitro MEA assay and in vivo CSF concentration of convulsants for IVIVE.•In vitro MEA assay with neurons have the potential to replace animal experiments.
Advanced glycation end products (AGEs) and their receptor (RAGE) play a role in tubulointerstitial damage in diabetic nephropathy. Recently, metformin has been shown to ameliorate tubular injury both ...in cell culture and diabetic animal model. However, effects of metformin on AGEs-induced tubular cell apoptosis and damage remain unknown. We examined here whether and how metformin could block the AGEs-RAGE-elicited tubular cell injury in vitro. Gene expression level was evaluated by real-time reverse-transcription polymerase chain reactions. Reactive oxygen species (ROS) generation was measured with dihydroethidium staining. Apoptosis was evaluated by DNA fragmentation and annexin V expression level. AGEs upregulated RAGE mRNA levels and subsequently increased ROS generation and intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and transforming growth factor-β gene expression in human renal proximal tubular cells, all of which were significantly blocked by the treatment of 0.01 and 0.1 mM metformin. Compound C, an inhibitor of AMP-activated protein kinase significantly blocked the effects of metformin on RAGE gene expression and ROS generation in AGEs-exposed tubular cells. Furthermore, metformin dose-dependently inhibited the AGEs-induced apoptotic cell death of tubular cells; 1 mM metformin completely suppressed the pro-apoptotic effects of AGEs in 2 different assay systems. Our present study suggests that metformin could inhibit the AGEs-induced apoptosis and inflammatory and fibrotic reactions in tubular cells probably by reducing ROS generation via suppression of RAGE expression through AMP-activated protein kinase activation. Metformin may protect against tubular cell injury in diabetic nephropathy by blocking the AGEs-RAGE-ROS axis.
Metformin use has been reported to decrease breast cancer incidence and mortality in diabetic patients. We have previously shown that advanced glycation end products (AGEs) and their receptor (RAGE) ...interaction stimulate growth and/or migration of pancreatic cancer and melanoma cells. However, effects of metformin on AGEs-RAGE axis in breast cancers remain unknown. We examined here whether and how metformin could block the AGEs-induced growth and vascular endothelial growth factor (VEGF) expression in MCF-7 breast cancer cells. Cell proliferation was measured with an electron coupling reagent WST-1 based colorimetric assay. Gene expression level was evaluated by real-time reverse-transcription polymerase chain reactions. AGEs significantly increased cell proliferation of MCF-7 cells, which was completely prevented by the treatment with 0.01 or 0.1 mM metformin or anti-RAGE antibodies. Furthermore, metformin at 0.01 mM completely suppressed the AGEs-induced upregulation of RAGE and VEGF mRNA levels in MCF-7 cells. An inhibitor of AMP-activated protein kinase, compound C significantly blocked the growth-inhibitory and RAGE and VEGF suppressing effects of metformin in AGEs-exposed MCF-7 cells. Our present study suggests that metformin could inhibit the AGEs-induced growth and VEGF expression in MCF-7 breast cancer cells by suppressing RAGE gene expression via AMP-activated protein kinase pathway. Metformin may protect against breast cancer expansion in diabetic patients by blocking the AGEs-RAGE axis.
“Why are the tin isotopes soft?” has remained, for the past decade, an open problem in nuclear structure physics: models which reproduce the isoscalar giant monopole resonance (ISGMR) in the ...“doubly-closed shell” nuclei, 90Zr and 208Pb, overestimate the ISGMR energies of the open-shell tin and cadmium nuclei, by as much as 1 MeV. In an effort to shed some light onto this problem, we present results of detailed studies of the ISGMR in the molybdenum nuclei, with the goal of elucidating where–and how–the softness manifests itself between 90Zr and the cadmium and tin isotopes. The experiment was conducted using the 94,96,98,100Mo(α,α′) reaction at Eα=386 MeV. A comparison of the results with relativistic, self-consistent Random-Phase Approximation calculations indicates that the ISGMR response begins to show softness in the molybdenum isotopes beginning with A=92.
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