Effects to cerebral oxygenation by arteriovenous fistula creation in patients with chronic kidney disease.

BACKGROUND: Vascular access, including arteriovenous fistula (AVF), is essential in patients undergoing hemodialysis (HD). However, the presence of AVF is non-physiological in humans and could pose a burden to the systemic circulation or tissue microcirculation, potentially affecting tissue oxygenation, including in the brain. Recently, near-infrared spectroscopy has been used to measure regional oxygen saturation (rSO2) as a marker of cerebral oxygenation in various settings, including in patients undergoing HD. Thus far, no studies have reported changes in cerebral rSO2 before and after AVF creation. This study aimed to monitor the differences in cerebral oxygenation before and after AVF creation and to clarify the clinical factors affecting the changes in cerebral rSO2. METHODS: Forty-eight patients (34 men, 14 women) with chronic kidney disease (CKD) who were not undergoing dialysis and newly created AVF were recruited. Cerebral rSO2 values before and after AVF creation were evaluated using near-infrared spectroscopy (INVOS 5100c). RESULTS: Cerebral rSO2 values were significantly changed from 60.3% ± 7.5% to 58.4% ± 6.8% before and after AVF creation in all patients (p < 0.001). Cerebral rSO2 were also lower in patients with diabetes mellitus (DM) than in those without DM (57.5 ± 7.1 vs 63.7 ± 6.5, p = 0.003) before surgery; however, no differences of changes in cerebral rSO2 were observed between the two groups after AVF creation. Additionally, multivariate regression analysis identified changes in HR (standardized coefficient: 0.436) as independent factors associated with changes in cerebral rSO2. CONCLUSION: Surgically created AVF was associated with the deterioration of cerebral rSO2 in patients with CKD not undergoing dialysis. Notably, AVF could cause cerebral hypoxia, and thus further studies are needed to clarify the clinical factors influencing changes in cerebral oxygenation after AVF creation.

Hepatic Oxygenation Changes and Symptomatic Intradialytic Hypotension.

INTRODUCTION: Clinical studies on differences among changes in cerebral and hepatic oxygenation during hemodialysis (HD) in patients with and without intradialytic hypotension (IDH) are limited. We investigated changes in intradialytic cerebral and hepatic oxygenation before systolic blood pressure (SBP) reached the nadir during HD and compared these differences between patients with and without symptomatic IDH. METHODS: We analyzed data from 109 patients with (n = 23) and without (n = 86) symptomatic IDH who were treated with HD. Cerebral and hepatic regional oxygen saturation (rSO2), as a marker of tissue oxygenation and circulation, was monitored during HD using an INVOS 5100c oxygen saturation monitor. Changes in cerebral or hepatic rSO2 when SBP reached the nadir during HD were compared between the groups of patients. RESULTS: The cerebral rSO2 before HD in patients with and without symptomatic IDH was 49.7 ± 11.2% and 51.3 ± 9.1% (p = 0.491). %Changes in cerebral rSO2 did not significantly differ between the two groups from 60 min before the SBP nadir during HD. Hepatic rSO2 before HD in patients with and without symptomatic IDH was 58.5 ± 15.4% and 57.8 ± 15.9% (p = 0.869). The %changes in hepatic rSO2 were significantly lower in patients with symptomatic IDH than in those without throughout the observational period (p < 0.001). We calculated the area under the receiver operating characteristic curve (AUC) and estimated cutoff values for changes in hepatic rSO2 as a symptomatic IDH predictor. The predictive ability at 5 and 40 min before symptomatic IDH onset was excellent, with AUCs and cutoff values of 0.847 and 0.841, and -10.9% and -5.0%, respectively. CONCLUSIONS: Hepatic oxygenation significantly decreased more in patients with symptomatic IDH before its onset, than in those without symptomatic IDH, whereas changes in cerebral oxygenation did not differ. Evaluating changes in hepatic oxygenation during HD might help to predict symptomatic IDH.

Improved Reliability of Electromyography-Based Neuromuscular Monitoring During Laparoscopic Surgery Achieved by the Modified Attachment Method for Nihon-Kohden NM-345Y™ Stimulating Electrodes: A Case Report.

Neuromuscular monitoring is crucial during the administration of neuromuscular blocking agents owing to individual variations in their effects. In electromyography (EMG)-based neuromuscular monitoring using the EMG electrodes (NM-345Y™, Nihon-Kohden Corporation, Tokyo, Japan) following the manufacturer-recommended attachment method, the accuracy of neuromuscular monitoring may be reduced when forearm limb position is changed. We previously devised a novel attachment method for NM-345Y™ stimulating electrodes in adult volunteers to maintain stable monitoring accuracy despite changes in forearm position. Its effectiveness in clinical practice was evaluated by conducting a descriptive study on a 52-year-old woman undergoing laparoscopic uterine surgery. NM-345Y™ electrodes were attached to each forearm following the manufacturer's recommendations (Pattern N) and our novel method (Pattern C). In Pattern C, NM-345Y™ was attached without ultrasound guidance so that the ulnar nerve crossed the line connecting the centers of the anode and cathode of the stimulating electrode. Pattern C exhibited consistent EMG-based monitoring accuracy even with changes in forearm position despite a smaller stimulus current value at calibration. Additionally, Pattern C displayed reliable recovery of the train-of-four (TOF) response after sugammadex administration in the original forearm position, with no observed adverse events. In contrast, Pattern N showed unstable monitoring accuracy after forearm position changes, highlighting the danger of imprecise EMG-based neuromuscular monitoring during the administration of neuromuscular blocking agents. The study's strength lies in identifying Pattern C, where the ulnar nerve crosses the line connecting the anode and cathode, significantly enhancing monitoring accuracy. This novel attachment method holds promise to improve EMG-based neuromuscular monitoring precision in surgery involving forearm limb position changes, although further research is required to assess its utility comprehensively.

Identification of Messenger RNA Signatures in Age-Dependent Renal Impairment.

In general populations, age-dependent renal impairment contributes to the progression of renal dysfunction. It has not been known which molecules are involved in age-dependent renal impairment. Messenger RNA (mRNA) has been reported to modulate various renal diseases, and we therefore investigated mRNA signatures in age-dependent renal impairment. We performed an initial microarray-profiling analysis to screen mRNAs, the expression levels of which changed in the kidneys of 50-week-old senescence-accelerated prone (SAMP1) mice (which have accelerated age-dependent renal impairments) compared with those of 50 wk old senescence-accelerated-resistant (SAMR1) mice (which have normal aged kidneys) and with younger (10 wk old) SAMP1 and SAMR1 mice. We next assessed the expressions of mRNAs that were differentially expressed in the kidneys of SAMP1-50wk mice by conducting a quantitative real-time polymerase chain reaction (qRT-PCR) and compared the expressions among the SAMP1-10wk, SAMR1-10wk, and SAMR1-50wk mice. The results of the microarray together with the qRT-PCR analysis revealed five mRNAs whose expression levels were significantly altered in SAMP1-50wk mouse kidneys versus the control mice. The expression levels of the five mRNAs were increased in the kidneys of the mice with age-dependent renal impairment. Our findings indicate that the five mRNAs might be related and could become therapeutic targets for age-dependent renal impairment.

The Efficacy and Safety of Dotinurad on Uric Acid and Renal Function in Patients with Hyperuricemia and Advanced Chronic Kidney Disease: A Single Center, Retrospective Analysis.

Objective: We investigated the efficacy and safety of dotinurad, a selective urate reabsorption inhibitor, in hyperuricemic patients with advanced chronic kidney disease (CKD) (stage G3-5). Patients and Methods: We retrospectively analyzed the cases of 34 patients (mean age, 68.6 ± 13.3 years; 17 men and 17 women) after 12 months of dotinurad treatment based on the changes in uric acid (UA) and the urine protein-to-creatinine ratio (UPCR) plus the annual change in estimated glomerular filtration rate (eGFR). Hyperuricemia (UA ≥6.0 mg/dL) and advanced CKD (mean eGFR: 32.0 ± 13.3 mL/min/1.73m2; stage G3, n=17; G4, n=13; G5, n=4) were present in all of the patients. The cases of 34 matched individuals with similar propensity scores (who were not taking dotinurad) were analyzed as a control group. Results: UA values decreased significantly in the dotinurad group (7.1 ± 0.8 mg/dL to 5.9 ± 1.0 mg/dL, p<0.05) but those did not change in the control group. UPCR did not change in either group. Low-density lipoprotein cholesterol also decreased significantly in the dotinurad group (98.8 ± 43.4 mg/dL to 82.9 ± 33.1 mg/dL, p<0.05). With the 12-month dotinurad treatment, the annual change in the patients' eGFR was significantly improved from -6.0 ± 12.9 mL/min/1.73 m2/year to -0.9 ± 4.6 mL/min/1.73 m2/year (p<0.05), but there was no change in the control group. Conclusion: Dotinurad can decrease UA levels and might attenuate renal function decline in individuals with hyperuricemia and advanced CKD.

Effects of the attachment method of the stimulating electrodes Nihon-Kohden NM-345Y™ and changes in forearm position on stimulus current values during calibration in electromyography-based neuromuscular monitoring: a single-center experimental study.

PURPOSE: The traditionally recommended method for attaching electromyography (EMG) electrodes (NM-345Y™) during EMG-based neuromuscular monitoring developed by Nihon-Kohden may decrease the monitoring accuracy when forearm limb position changes. This study investigated methods for attaching stimulating electrodes that maintained stable EMG-based neuromuscular monitoring accuracy, regardless of forearm limb position changes. METHODS: This single-center experimental study recruited 28 healthy adults from October 2022 to December 2022. The NM-345Y™ was attached to the forearm using three patterns: Pattern N, electrodes attached according to the attachment pattern recommended by Nihon-Kohden; Pattern U, electrodes attached along the ulnar nerve identified using an ultrasound device; Pattern C, electrodes attached where the ulnar nerve crosses the line connecting the centers of the anode and cathode of the stimulating electrodes. The stimulus current values during calibration were measured at three forearm positions for each attachment pattern: supination 90 degrees; pronation 0 degrees; pronation 90 degrees. The differences in stimulus current values caused by forearm position changes were calculated as the difference between values at supination 90 degrees and pronation 0 degrees and between values at supination 90 degrees and pronation 90 degrees. RESULTS: Pattern C showed significantly smaller differences than Pattern N between the stimulus current values at supination 90 degrees and pronation 0 degrees (p = 0.018) and between the stimulus current values at supination 90 degrees and pronation 90 degrees (p = 0.008). CONCLUSION: Crossing the ulnar nerve with the line connecting the anode and cathode of the stimulating electrodes may stabilize EMG-based neuromuscular monitoring accuracy.

Differences between Hepatic and Cerebral Regional Tissue Oxygen Saturation at the Onset of Intradialytic Hypotension.

BACKGROUND: Intradialytic hypotension (IDH) is a critical pathological condition associated with all-cause mortality in patients undergoing hemodialysis (HD). However, few studies have investigated IDH-related changes in hepatic and cerebral regional tissue oxygen saturation (rSO2). This study investigated IDH-induced changes in hepatic and cerebral rSO2. METHODS: Hepatic and cerebral rSO2 during HD were measured using an INVOS 5100C oxygen saturation monitor, and their percentage (%) changes during the development of IDH were analyzed. Ninety-one patients undergoing HD were investigated, including twenty with IDH. RESULTS: In patients with IDH, % changes in hepatic and cerebral rSO2 decreased at the onset of IDH. Additionally, the % change in hepatic rSO2 was significantly larger than that in cerebral rSO2 (p < 0.001). In patients without IDH, no significant differences were found between the % changes in hepatic and cerebral rSO2 at the time of the lowest systolic blood pressure during HD. Multivariable linear regression analysis showed that the difference between the % changes in cerebral and hepatic rSO2 was significantly associated with the development of IDH (p < 0.001) and the ultrafiltration rate (p = 0.010). CONCLUSIONS: Hepatic and cerebral rSO2 significantly decreased during the development of IDH, and hepatic rSO2 was more significantly decreased than cerebral rSO2 at the onset of IDH.

Modifications of peripheral perfusion in patients with vasopressor-dependent septic shock treated with polymyxin B-direct hemoperfusion.

Abnormal peripheral perfusion (PP) worsens the prognosis of patients with septic shock. Polymyxin B-direct hemoperfusion (PMX-DHP) increases blood pressure and reduces vasopressor doses. However, the modification of PP following administration of PMX-DHP in patients with vasopressor-dependent septic shock have not yet been elucidated. A retrospective exploratory observational study was conducted in patients with septic shock treated with PMX-DHP. Pulse-amplitude index (PAI), vasoactive inotropic score (VIS), and cumulative fluid balance data were extracted at PMX-DHP initiation (T0) and after 24 (T24) and 48 (T48) h. Changes in these data were analyzed in all patients and two subgroups (abnormal PP [PAI < 1] and normal PP [PAI ≥ 1]) based on the PAI at PMX-DHP initiation. Overall, 122 patients (abnormal PP group, n = 67; normal PP group, n = 55) were evaluated. Overall and in the abnormal PP group, PAI increased significantly at T24 and T48 compared with that at T0, with a significant decrease in VIS. Cumulative 24-h fluid balance after PMX-DHP initiation was significantly higher in the abnormal PP group. PMX-DHP may be an effective intervention to improve PP in patients with abnormal PP; however, caution should be exercised as fluid requirements may differ from that of patients with normal PP.

Factors affecting intradialytic hepatic oxygenation: Associations between ultrafiltration rate and changes in systemic blood pressure.

INTRODUCTION: Hepato-splanchnic circulation influences the oxygenation of abdominal organs and is important in preventing a reduction in intradialytic blood volume. However, the association between changes in intradialytic hepato-splanchnic circulation and clinical factors remain unknown. METHODS: We enrolled 91 hemodialysis (HD) patients (20 with intradialytic hypotension (IDH) and 71 without IDH). During HD, hepatic regional oxygen saturation (rSO2), a marker of hepatic oxygenation reflecting hepato-splanchnic circulation and oxygenation, was monitored. Changes in hepatic rSO2 at the lowest systolic blood pressure (BP) during HD were analyzed to identify associations with clinical factors. RESULTS: Hepatic rSO2 levels were 55.8 ± 15.3% before HD and 53.8 ± 14.9% at the lowest systolic BP; therefore, % changes in hepatic rSO2 were -2.7 ± 11.3%. These values were significantly lower in patients with IDH than in those without IDH (-13.8 ± 9.3% vs 0.4 ± 9.8%, p < 0.001). Multivariable regression analysis showed that % changes in hepatic rSO2 were independently associated with % changes in systolic BP (standardized coefficient: 0.416) and ultrafiltration rate (-0.206). Furthermore, % changes in mean BP (0.304) were identified as affecting % changes in hepatic rSO2 instead of those in systolic BP. CONCLUSIONS: Changes in intradialytic hepatic oxygenation is associated with ultrafiltration rate and changes in systemic BP. Further studies are required to clarify the directionality of the association between changes in hepatic oxygenation and changes in systemic BP during HD.

Relationship between perfusion index and central temperature before and after induction of anesthesia in laparoscopic gastrointestinal surgery: A prospective cohort study.

The perfusion index (PI) cutoff value before anesthesia induction and the ratio of PI variation after anesthesia induction remain unclear. This study aimed to clarify the relationship between PI and central temperature during anesthesia induction, and the potential of PI in individualized and effective control of redistribution hypothermia. This prospective observational single center study analyzed 100 gastrointestinal surgeries performed under general anesthesia from August 2021 to February 2022. The PI was measured as peripheral perfusion, and the relationship between central and peripheral temperature values was investigated. Receiver operating characteristic curve analysis was performed to identify baseline PI before anesthesia, which predicts a decrease in central temperature 30 minutes after anesthesia induction, and the rate of change in PI that predicts the decrease in central temperature 60 minutes after anesthesia induction. In cases with a central temperature decrease of ≥ 0.6°C after 30 minutes, the area under the curve was 0.744, Youden index was 0.456, and the cutoff value of baseline PI was 2.30. In cases with a central temperature decrease of ≥ 0.6°C after 60 minutes, the area under curve was 0.857, Youden index was 0.693, and the cutoff value of the PI ratio of variation after 30 minutes of anesthesia induction was 1.58. If the baseline PI is ≤ 2.30 and the PI 30 minutes after anesthesia induction is at least 1.58-fold the PI ratio of variation, there is a high probability of a central temperature decrease of at least 0.6°C within 30 minutes after 2 time points.

Effects of roxadustat on anemia, iron metabolism, and lipid metabolism in patients with non-dialysis chronic kidney disease.

Background: We determined the effects of roxadustat on the values of anemia, iron metabolism, renal function, proteinuria, and lipid metabolism and identified the associated factors of the change in hemoglobin levels after roxadustat administration in non-dialysis chronic kidney disease (CKD) patients who were receiving an erythropoietin-stimulating agent (ESA). Methods: We conducted retrospective analysis of the changes in hemoglobin, serum ferritin, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride levels; transferrin saturation; the estimated glomerular filtration rate; and the urinary protein/creatinine ratio over 24 weeks after the change from an ESA to roxadustat in 50 patients with non-dialysis CKD and anemia (roxadustat group). Seventy-two patients with non-dialysis CKD and anemia who proceeded ESA therapy were used as the control (ESA) group. Results: We observed no significant between-group differences in clinical parameters at baseline except for the significantly lower hemoglobin concentration and lower proportion of diabetes mellitus in the roxadustat group. The hemoglobin concentration was significantly higher in the roxadustat group after 24 weeks (11.3 ± 1.2 versus 10.3 ± 1.0 g/dL; value of p < 0.05), whereas the transferrin saturation, ferritin concentration, estimated glomerular filtration rate, and urinary protein/creatinine ratio were not different between the two groups. TC (135.9 ± 40.0 versus 165.3 ± 38.4 mg/dL; value of p < 0.05), LDL-C (69.1 ± 28.3 versus 87.2 ± 31.5 mg/dL; value of p < 0.05), HDL-C (41.4 ± 13.5 versus 47.2 ± 15.3 mg/dL; value of p < 0.05), and triglyceride concentrations (101.5 ± 52.7 versus 141.6 ± 91.4 mg/dL, value of p < 0.05) were significantly lower in the roxadustat group compared with the ESA group at 24 weeks. Multiple linear regression analysis showed that the roxadustat dose at baseline (standard coefficient [ß] = 0.280, value of p = 0.043) was correlated with the change in the hemoglobin levels during the first 4 weeks of roxadustat treatment, whereas age (ß = 0.319, value of p = 0.017) and the roxadustat dose at 24 weeks (ß = -0.347, value of p = 0.010) were correlated with the hemoglobin concentration after 24 weeks of roxadustat administration. Conclusion: Roxadustat can improve anemia and reduce serum cholesterol and triglyceride levels in non-dialysis CKD patients after the patients' treatment was switched from an ESA without affecting renal function or proteinuria. These results indicate that roxadustat has superior effects to ESAs regarding anemia and lipid metabolism at the dose selected for the comparison in patients with non-dialysis CKD.

Effect of remimazolam on the incidence of delirium after transcatheter aortic valve implantation under general anesthesia: a retrospective exploratory study.

PURPOSE: Delirium after transcatheter aortic valve implantation (TAVI) should be prevented because it is associated with worse patient outcomes. Perioperative administration of benzodiazepines is a risk factor for postoperative delirium; however, the association between remimazolam, a newer ultrashort-acting benzodiazepine for general anesthesia, and postoperative delirium remains unclear. This study aimed to evaluate whether remimazolam administration during TAVI under general anesthesia affected the incidence of postoperative delirium. METHODS: This single-center retrospective study recruited all adult patients who underwent transfemoral TAVI (TF-TAVI) under general anesthesia between March 2020 and May 2022. Patients were divided into the remimazolam (R) and propofol (P) groups according to the sedative used for anesthesia. In the R group, all patients received flumazenil after surgery. The primary endpoint was the incidence of delirium within 3 days after surgery. Factors associated with delirium after TF-TAVI were examined by multiple logistic regression analysis. RESULTS: Ninety-eight patients were included in the final analysis (R group, n = 40; P group, n = 58). The incidence of postoperative delirium was significantly lower in the R group than in the P group (8% vs. 26%, p = 0.032). Multiple logistic regression analysis revealed that remimazolam (odds ratio 0.17, 95% CI 0.04-0.80, p = 0.024) was independently associated with the incidence of postoperative delirium, even after adjustment for age, sex, preoperative cognitive function, history of stroke, and TF-TAVI approach. CONCLUSION: Remimazolam may benefit TF-TAVI in terms of postoperative delirium; however, its usefulness must be further evaluated in extensive prospective studies.

miR-122-5p Regulates Renal Fibrosis In Vivo.

The role of exogenous microRNAs (miRNAs) in renal fibrosis is poorly understood. Here, the effect of exogenous miRNAs on renal fibrosis was investigated using a renal fibrosis mouse model generated by unilateral ureteral obstruction (UUO). miRNA microarray analysis and quantitative reverse-transcription polymerase chain reaction showed that miR-122-5p was the most downregulated (0.28-fold) miRNA in the kidneys of UUO mice. The injection of an miR-122-5p mimic promoted renal fibrosis and upregulated COL1A2 and FN1, whereas an miR-122-5p inhibitor suppressed renal fibrosis and downregulated COL1A2 and FN1. The expression levels of fibrosis-related mRNAs, which were predicted targets of miR-122-5p, were evaluated. The expression level of TGFBR2, a pro-fibrotic mRNA, was upregulated by the miR-122-5p mimic, and the expression level of FOXO3, an anti-fibrotic mRNA, was upregulated by the miR-122-5p inhibitor. The protein expressions of TGFBR2 and FOXO3 were confirmed by immunohistochemistry. Additionally, the expression levels of LC3, downstream anti-fibrotic mRNAs of FOXO3, were upregulated by the miR-122-5p inhibitor. These results suggest that miR-122-5p has critical roles in renal fibrosis.

Systemic injection of nicotinic acetylcholine receptor antagonist mecamylamine affects licking, eyelid size, and locomotor and autonomic activities but not temporal prediction in male mice.

Nicotinic acetylcholine receptors are thought to be associated with a wide range of phenomena, such as movement, learning, memory, attention, and addiction. However, the causal relationship between nicotinic receptor activity and behavior remains unclear. Contrary to the studies that examined the functions of muscarinic acetylcholine receptors, the role of the nicotinic acetylcholine receptors on behavior has not been examined as extensively. Here, we examined the effects of intraperitoneal injection of mecamylamine, a nicotinic acetylcholine receptor antagonist, on the performance of male mice in a head-fixed temporal conditioning task and a free-moving open-field task. The head-fixed experimental setup allowed us to record and precisely quantify the licking response while the mice performed the behavioral task with no external cues. In addition, by combining the utility of the head-fixed experimental design with computer vision analysis based on deep learning algorithms, we succeeded in quantifying the eyelid size of awake mice. In the temporal conditioning task, we delivered a 10% sucrose solution every 10 s using a blunt-tipped needle placed within the licking distance of the mice. After the training, the mice showed increased anticipatory licking toward the timing of sucrose delivery, suggesting that the mice could predict the timing of the reward. Systemic injection of mecamylamine decreased licking behavior and caused eye closure but had no effect on learned conditioned predictive behavior in the head-fixed temporal conditioning task. In addition, the injection of mecamylamine decreased spontaneous locomotor activity in a dose-dependent manner in the free-moving open-field task. The results in the open-field experiments further revealed that the effect of mecamylamine on fecal output and urination, suggesting the effects on autonomic activities. Our achievement of successful eyelid size recording has potential as a useful approach in initial screening for drug discovery. Our study paves a way forward to understanding the role of nicotinic acetylcholine receptors on learning and behavior.

MicroRNA Expression Profiling in Age-Dependent Renal Impairment.

Background: Age-dependent renal impairment contributes to renal dysfunction in both the general population and young and middle-aged patients with renal diseases. Pathological changes in age-dependent renal impairment include glomerulosclerosis and tubulointerstitial fibrosis. The molecules involved in age-dependent renal impairment are not fully elucidated. MicroRNA (miRNA) species were reported to modulate various renal diseases, but the miRNA species involved in age-dependent renal impairment are unclear. Here, we investigated miRNAs in age-dependent renal impairment, and we evaluated their potential as biomarkers and therapeutic targets. Methods: We conducted an initial microarray profiling analysis to screen miRNAs whose expression levels changed in kidneys of senescence-accelerated resistant (SAMR1)-10-week-old (wk) mice and SAMR1-50wk mice and senescence-accelerated prone (SAMP1)-10wk mice and SAMP1-50wk mice. We then evaluated the expressions of differentially expressed miRNAs in serum from 13 older patients (>65 years old) with age-dependent renal impairment (estimated glomerular filtration ratio <60 mL/min/1.73 m2) by a quantitative real-time polymerase chain reaction (qRT-PCR) and compared the expressions with those of age-matched subjects with normal renal function. We also administered miRNA mimics or inhibitors (5 nmol) with a non-viral vector (polyethylenimine nanoparticles: PEI-NPs) to SAMP1-20wk mice to investigate the therapeutic effects. Results: The qRT-PCR revealed a specific miRNA (miRNA-503-5p) whose level was significantly changed in SAMP1-50wk mouse kidneys in comparison to the controls. The expression level of miRNA-503-5p was upregulated in the serum of the 13 patients with age-dependent renal impairment compared to the age-matched subjects with normal renal function. The administration of a miRNA-503-5p-inhibitor with PEI-NPs decreased the miRNA-503-5p expression levels, resulting in the inhibition of renal fibrosis in mice via an inhibition of a pro-fibrotic signaling pathway and a suppression of glomerulosclerosis in mice by inhibiting intrinsic signaling pathways. Conclusion: The serum levels of miRNA-503-5p were decreased in patients with age-dependent renal impairment. However, inhibition of miRNA-503-5p had no effect on age-dependent renal impairment, although inhibition of miRNA-503-5p had therapeutic effects on renal fibrosis and glomerulosclerosis in an in vivo animal model. These results indicate that miRNA-503-5p might be related to age-dependent renal impairment.

Clinical Factors Associated with Serum Magnesium Concentration in Patients Undergoing Peritoneal Dialysis: A Single-Center Observational Study.

Purpose: Magnesium (Mg) is an essential element that is associated with various physiological functions, such as maintenance of blood pressure, muscle contraction, and nerve function. In patients undergoing hemodialysis, hypomagnesemia is associated with cardiovascular and all-cause mortality. However, in patients undergoing peritoneal dialysis (PD), clinical factors associated with Mg have not been fully investigated. Patients and Methods: Clinical factors including anthropometric data, comorbidities, laboratory data, medications, and dialysis methods were collected from the medical records of patients undergoing PD. The associations of these factors with the serum Mg concentration were investigated by univariate and multivariate analyses. Results: Sixty patients undergoing PD were investigated. The univariate analysis showed that the serum Mg concentration was significantly associated with treatment by hybrid PD (daily PD + once-weekly hemodialysis) (ß = 0.264, P = 0.04), administration of phosphate binders (ß = 0.294, P = 0.02), the serum C-reactive protein concentration (ß = -0.318, P = 0.01), the serum potassium (K) concentration (ß = 0.451, P < 0.01), and the serum intact parathormone concentration (ß = -0.333, P = 0.01). The multivariate analysis using these factors showed an independent association between the serum Mg and K concentrations (ß = 0.333, P = 0.01). Conclusion: The serum Mg concentration was independently associated with the serum K concentration in patients undergoing PD.

Delivery of Exogenous Artificially Synthesized miRNA Mimic to the Kidney using Polyethylenimine Nanoparticles in Several Kidney Disease Mouse Models.

microRNSa (miRNAs), small noncoding RNAs (21-25 bases) that are not translated into proteins, inhibit lots of target messenger RNAs (mRNAs) by destabilizing and inhibiting their translation in various kidney diseases. Therefore, alternation of miRNA expression by exogenous artificially synthesized miRNA mimics is a potentially useful treatment option for inhibiting the development of many kidney diseases. However, because serum RNAase immediately degrades systematically administered exogenous miRNA mimics in vivo, delivery of miRNA to the kidney remains a challenge. Therefore, vectors that can protect exogenous miRNA mimics from degradation by RNAase and significantly deliver them to the kidney are necessary. Many studies have used viral vectors to deliver exogenous miRNA mimics or inhibitors to the kidney. However, viral vectors may cause an interferon response and/or genetic instability. Therefore, the development of viral vectors is also a hurdle for the clinical use of exogenous miRNA mimics or inhibitors. To overcome these concerns regarding viral vectors, we developed a nonviral vector method to deliver miRNA mimics to the kidney using tail vein injection of polyethylenimine nanoparticles (PEI-NPs), which led to significant overexpression of target miRNAs in several mouse models of kidney disease.

Quantitative Real-time Polymerase Chain Reaction Evaluation of MicroRNA Expression in Kidney and Serum of Mice with Age-dependent Renal Impairment.

MicroRNAs (miRNAs) are small, noncoding RNAs consisting of 21-25 bases. They are not translated into proteins but rather work to impede the functioning of their target messenger RNAs (mRNAs) by destabilizing them and disrupting their translation. Although the miRNA expression profiles in various mouse organs and tissues have been investigated, there have been no standard methods for purifying and quantifying mouse kidney and serum miRNAs. We have established an effective and reliable method for extracting and evaluating the miRNA expression in the serum and kidney of mice with age-dependent renal impairment. The method uses quantitative reverse-transcription-polymerase chain reaction (qRT-PCR), and the protocol requires six steps: (1) preparing senescence-accelerated mouse resistance 1 (SAMR1) mice and senescence-accelerated mouse prone (SAMP1) mice; (2) extracting serum samples from these mice; (3) extracting a kidney sample from each mouse; (4) extracting total RNA (including miRNA) from kidney and serum samples from each mouse; (5) the synthesis of complementary DNA (cDNA) with reverse transcription from the miRNA; (6) conducting a qRT-PCR using the cDNA obtained. This protocol was used to confirm that, compared to the controls, the expression of miRNA-7218-5p and miRNA-7219-5p was significantly changed in the kidney and serum of a mouse model of age-dependent renal impairment. This protocol also clarified the relationship between the kidney and serum of the mouse model of age-dependent renal impairment. This protocol can be used to determine miRNA expression in the kidney and serum of mice with age-dependent renal impairment.

MicroRNA expression profiling in acute kidney injury.

The aim of this study was to identify miRNAs that regulate AKI and develop their applications as diagnostic biomarkers and therapeutic agents. First, kidney tissues from two different AKI mouse models, namely, AKI induced by the administration of lipopolysaccharide (LPS) causing sepsis (LPS-AKI mice) and AKI induced by renal ischemia-reperfusion injury (IRI-AKI mice), were exhaustively screened for their changes of miRNA expression compared with that of control mice by microarray analysis followed by quantitative RT-PCR. The initial profiling newly identified miRNA-5100, whose expression levels significantly decreased in kidneys in both LPS-AKI mice and IRI-AKI mice. Next, the administration of miRNA-5100-mimic conjugated with a nonviral vector, polyethylenimine nanoparticles (PEI-NPs), via the tail vein significantly induced miRNA-5100 overexpression in the kidney and prevented the development of IRI-AKI mice by inhibiting several apoptosis pathways in vivo. Furthermore, serum levels of miRNA-5100 in patients with AKI were identified as significantly lower than those of healthy subjects. ROC analysis showed that the serum expression level of miRNA-5100 can identify AKI (cut-off value 0.14, AUC 0.96, sensitivity 1.00, specificity 0.833, p<0.05). These results suggest that miRNA-5100 regulates AKI and may be useful as a novel diagnostic biomarker and therapeutic target for AKI.