MicroRNAs in Podocyte Injury in Diabetic Nephropathy

Diabetic nephropathy is one of the major complications of diabetes mellitus and is the leading cause of end-stage renal disease worldwide. Podocyte injury contributes to the development of diabetic nephropathy. However, the molecules that regulate podocyte injury in diabetic nephropathy have not been fully clarified. MicroRNAs (miRNAs) are small non-coding RNAs that can inhibit the translation of target messenger RNAs. Previous reports have described alteration of the expression levels of many miRNAs in cultured podocyte cells stimulated with a high glucose concentration and podocytes in rodent models of diabetic nephropathy. The associations between podocyte injury and miRNA expression levels in blood, urine, and kidney in patients with diabetic nephropathy have also been reported. Moreover, modulation of the expression of several miRNAs has been shown to have protective effects against podocyte injury in diabetic nephropathy in cultured podocyte cells in vitro and in rodent models of diabetic nephropathy in vivo. Therefore, this review focuses on miRNAs in podocyte injury in diabetic nephropathy, with regard to their potential as biomarkers and miRNA modulation as a therapeutic option.

MicroRNAs in Sarcopenia: A Systematic Review

Sarcopenia, which is characterized by the loss of skeletal muscle, has been reported to contribute to development of physical disabilities, various illnesses, and increasing mortality. MicroRNAs (miRNAs) are small non-coding RNAs that inhibit translation of target messenger RNAs. Previous studies have shown that miRNAs play pivotal roles in the development of sarcopenia. Therefore, this systematic review focuses on miRNAs that regulate sarcopenia.

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.

Association of cerebral oxygenation with estimated glomerular filtration rate and cognitive function in chronic kidney disease patients without dialysis therapy

Background

A decline in estimated glomerular filtration rate (eGFR) is reportedly associated with increased prevalence rates of cognitive impairment. However, data concerning the association between the cerebral saturation of oxygen (rSO₂) and cognitive function of patients with chronic kidney disease (CKD) is limited. This study aimed to (i) elucidate the clinical factors associating with cerebral rSO₂ and (ii) investigate the association between cerebral rSO2 and cognitive assessment in CKD patients.

Methods

A total of 40 CKD patients not requiring dialysis (26 men and 14 women; mean age, 61.0 ± 2.7 years) were recruited. The numbers of patients at each CKD stage were as follows: G1, 5; G2, 8; G3a, 6; G3b, 5; G4, 11; and G5, 5. Cerebral rSO₂ was monitored at the forehead using the oxygen saturation monitor INVOS 5100C. The cognitive function of each patient was confirmed using the Mini-Mental State Examination (MMSE).

Results

Cerebral rSO₂ levels were significantly higher in CKD patients than in hemodialysis patients (63.8 ± 1.5% vs. 44.9 ± 2.2%, p < 0.001). Multiple regression analysis showed that cerebral rSO₂ was independently associated with eGFR (standardized coefficient: 0.530), serum albumin concentration (standardized coefficient: 0.365), and serum sodium concentration (standardized coefficient: 0.224). Furthermore, MMSE showed a significantly positive correlation with cerebral rSO₂ (r = 0.624, p < 0.001).

Conclusions

Cerebral rSO₂ was affected by eGFR and serum albumin and sodium concentrations in CKD patients. Furthermore, cerebral rSO₂ monitoring, which reflected MMSE scores, might be a useful method for assessing cognitive function in CKD patients.

MicroRNA Expression Profiling in Diabetic Kidney Disease

The microRNAs (miRNAs) that can regulate diabetic kidney disease (DKD) have not been fully characterized. The aim of this study was to identify the miRNAs that affect DKD and could be used as specific biomarkers or therapeutic agents. First, kidney tissues from two DKD mouse models and control mice were screened for differences in miRNA expression by microarray analysis followed by quantitative real-time reverse transcription-PCR. Six miRNAs were differentially expressed from controls in both DKD mouse models. Among them, miRNA-125b-5p and miRNA-181b-5p were exclusively downregulated in the DKD mouse model. Next, we administered miRNA-181b-5p-mimic to DKD mice, which reduced the albuminuria and abnormal mesangial expansion. Pathway analysis and database research revealed that overexpression of miRNA-181b-5p significantly altered the expression of seven mRNAs in six known signaling pathways in the kidneys of DKD mice. Furthermore, the serum level of miRNA-125b-5p was significantly higher in patients with DKD (1.89±0.40-fold, P<0.05) compared with patients with other kidney diseases (0.94±0.13-fold) and healthy subjects (1.00±0.19-fold). Serum levels of miRNA-181b-5p were lower in patients with DKD (0.30±0.06-fold, P<0.05) compared with patients with other kidney diseases (1.06±0.20-fold) and healthy subjects (1.00±0.16-fold). These results suggest that miRNA-125b-5p and miRNA-181b-5p may represent novel diagnostic biomarkers and that miRNA-181b-5p may represent a therapeutic target for DKD.

Effects of Roxadustat on the Anemia and Iron Metabolism of Patients Undergoing Peritoneal Dialysis

Background: We investigated the effects of roxadustat on the anemia, iron metabolism, peritoneal membrane function, and residual renal function; and determined the factors associated with the administration of roxadustat in patients who were undergoing peritoneal dialysis.

Methods: We retrospectively analyzed the changes in hemoglobin, serum ferritin, transferrin saturation (TSAT), 4-h dialysate/plasma creatinine, and renal weekly urea clearance over the 24 weeks following the change from an erythropoiesis-stimulating agent (ESA) to roxadustat in 16 patients who were undergoing peritoneal dialysis and had anemia (Roxadustat group). Twenty-three peritoneal dialysis patients who had anemia and continued ESA served as a control group (ESA group).

Results: There were no significant differences in hemoglobin, serum ferritin, TSAT, 4-h dialysate/plasma creatinine, or renal weekly urea clearance between the two groups at baseline. The hemoglobin concentration was significantly higher in the Roxadustat group than in the ESA group after 24 weeks (11.6 ± 1.0 g/dL vs. 10.3 ± 1.1 g/dL, p < 0.05), whereas the ferritin concentration and TSAT were significantly lower (139.5 ± 102.0 ng/mL vs. 209.2 ± 113.1 ng/mL, p < 0.05; and 28.1 ± 11.5% vs. 44.8 ± 10.4%, p < 0.05, respectively). The changes in 4-h dialysate/plasma creatinine and renal weekly urea clearance did not differ between the two groups. Linear regression analysis revealed that the serum potassium concentration correlated with the dose of roxadustat at 24 weeks (standard coefficient = 0.580, p = 0.019).

Conclusion: Roxadustat may improve the anemia and reduce the serum ferritin and TSAT of the peritoneal dialysis patients after they were switched from an ESA, without association with peritoneal membrane function or residual renal function.

Idiopathic hypereosinophilic syndrome in hemodialysis patients: Case reports

RATIONALE

Herein, we report 3 hemodialysis patients with idiopathic hypereosinophilic syndrome who were successfully treated using corticosteroid therapy.

PATIENT CONCERNS

Case 1 was a 63-year-old man who was undergoing hemodialysis because of bilateral nephrectomy and developed hypereosinophilia with digestive symptoms, myocardial injury, and intradialytic hypotension. Case 2 was an 83-year-old man who was undergoing hemodialysis because of nephrosclerosis and developed hypereosinophilia with pruritus, myocardial injury, and intradialytic hypotension. Case 3 was a 59-year-old man who was undergoing hemodialysis because of diabetic nephropathy and developed hypereosinophilia with pruritus, myocardial injury, and intradialytic hypotension.

DIAGNOSES

All 3 patients presented with hypereosinophilia (eosinophil count ≥1500 /μL for more than 1 month) and multiple-organ involvement (intradialytic hypotension, cardiac injury, digestive symptoms, and allergic dermatitis). A specific cause for the hypereosinophilia was not identified by systemic computed tomography, electrocardiography, echocardiography, bone marrow examination, or blood tests. Furthermore, Case 2 and 3 had not recently started taking any new drugs and drug-induced lymphocyte stimulation tests were negative in Case 1. Therefore, they were diagnosed with idiopathic hypereosinophilic syndrome.

INTERVENTIONS

All 3 patients received corticosteroid therapy with prednisolone at a dose of 40 mg/d, 30 mg/d, and 60 mg/d in Case 1, 2, and 3, respectively.

OUTCOMES

Their digestive symptoms, pruritus, intradialytic hypotension, and serum troponin I concentrations were immediately improved alongside reductions in their eosinophil counts.

LESSONS

There have been few case reports of idiopathic hypereosinophilic syndrome in patients undergoing hemodialysis. We believe that recording of the clinical findings and treatments of such patients is mandatory to establish the optimal management of idiopathic hypereosinophilic syndrome.

Factors Associated with Uremic Pruritus in Patients Undergoing Peritoneal Dialysis

Aim

The aim of this study was to investigate different intensities of uremic pruritus in the daytime and nighttime, as well as contributing factors, in patients undergoing peritoneal dialysis (PD).

Methods

A total of 46 patients (31 males, 15 females) with a mean age of 59.4±14.7 years and mean PD vintage of 29.2±25.2 months were enrolled in this single-center, prospective, cross-sectional study. The intensity of uremic pruritus in the daytime and nighttime was assessed using a visual analog scale (VAS). The relationships between intensity and various clinical and laboratory parameters were analyzed using multiple linear regression analyses.

Results

The most common site of uremic pruritus was on the back (70%), followed by lower limbs (67%), chest and abdomen (59%), upper limbs (28%), and head and neck (22%). Mean VAS scores were higher in the nighttime compared with the daytime (4.5±3.3 vs. 3.5±2.7, P=0.02). Only male sex was correlated with higher uremic pruritus intensity in the daytime (standard coefficient [β]=0.310, P=0.036). PD vintage (β=0.415, P=0.004) and topical medicines, including moisturizer and topical corticosteroid use (β=0.345, P=0.019), were independently correlated with higher uremic pruritus intensity in the nighttime.

Conclusion

Uremic pruritus intensity was greater in the nighttime than in the daytime in PD patients. Male sex was associated with higher uremic pruritus intensity in the daytime, whereas PD vintage and topical medicine use were associated with higher uremic pruritus intensity in the nighttime.

Effect of Transcatheter Aortic Valve Implantation on the Immune Response Associated With Surgical Aortic Valve Replacement

The immune response after transcatheter aortic valve implantation (TAVI) in comparison to that after surgical aortic valve replacement (SAVR) remains to be fully elucidated. In a 2-part study, we assessed laboratory data obtained before, immediately after, and 24 and 48 hours after SAVR (128 patients; age ≥80 [mean 82] years) or transfemoral TAVI (102 patients; age ≥80 [mean 86] years) performed for aortic stenosis. In-hospital mortalities were similar (3% vs 0%), but leukocyte counts and aspartate aminotransferase and creatine kinas concentrations were decreased immediately and 24 hours after surgery (all, p <0.001). We performed cytokine profiling in a SAVR group (11 patients; mean age, 77 years) and transfemoral TAVI group (12 patients; mean age, 84 years). By measuring normalized concentrations of 71 cytokines at 3 time points, we found a significant difference (defined as fold change >1.7 and p <0.05 [by Mann-Whitney U-test]) in 23 cytokines. The differentially expressed cytokines fell into 3 hierarchical clusters: cluster A (high increase after SAVR and suppressed increase after TAVI only immediately after surgery [CCL2, CCL4, and 2 others]), cluster B (high increase after SAVR and suppressed increase after TAVI at 2 time points [IL-1Ra, IL-6, IL-8, IL-10, and 5 others]), and cluster C (various patterns [TRAIL, CCL11, and 8 others]). Gene enrichment analysis identified multiple pathways associated with the inflammatory responses in SAVR and altered responses in TAVI, including cellular responses to tumor necrosis factor (p = 0.0035) and interleukin-1 (p = 0.0062). In conclusion, a robust inflammatory response follows SAVR, and a comparatively attenuated response follows TAVI.

Serum Zinc Concentration Correlates With Ferritin Concentration in Patients Undergoing Peritoneal Dialysis: A Cross-Sectional Study

Background: Zinc deficiency is common and is associated with erythropoietin resistant anemia, dysgeusia, and hypogonadism in patients undergoing hemodialysis. However, the prevalence and clinical effects of zinc deficiency in patients undergoing peritoneal dialysis (PD) have not been determined. Methods: This was a retrospective, cross-sectional study. The prevalence of serum zinc deficiency and the clinical factors related to serum zinc concentration were determined in 49 patients undergoing PD [mean age 59.5 years (±14.8 years), 38/49 were men (78.6%), median PD period 24.0 months (12.5-45.0 months)]. A serum zinc concentration <60 μg/dL was defined as serum zinc deficiency, and a serum zinc concentration between 60 and 80 μg/dL as possible serum zinc deficiency. Results: Serum zinc deficiency was present in 51% (25/49) of the patients, and possible serum zinc deficiency was present in 45% (22/49) of patients undergoing PD. Multivariate analysis showed that serum zinc concentration significantly correlated with serum ferritin concentration (β = 0.357, P < 0.01). Conclusions: The prevalences of serum zinc deficiency and possible serum deficiency are high and serum zinc concentration correlates with serum ferritin concentration in patients undergoing PD.

Quantitative Real-Time PCR Evaluation of microRNA Expressions in Mouse Kidney with Unilateral Ureteral Obstruction

MicroRNAs (miRNAs) are single stranded, non-coding RNA molecules that typically regulate gene expression at the post-transcriptional level by binding to partially complementary target sites in the 3' untranslated region (UTR) of messenger RNA (mRNA), which reduces the mRNA's translation and stability. The miRNA expression profiles in various organs and tissues of mice have been investigated, but standard methods for the purification and quantification of miRNA in mouse kidney have not been available. We have established an effective and reliable method for extracting and evaluating miRNA expression in mouse kidney with renal interstitial fibrosis by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The protocol required five steps: (1) creation of sham and unilateral ureteral obstruction (UUO) mice; (2) extraction of kidney samples from the UUO mice; (3) extraction of total RNA, which includes miRNA, from the kidney samples; (4) complementary DNA (cDNA) synthesis with reverse transcription from miRNA; and (5) qRT-PCR using the cDNA. Using this protocol, we successfully confirmed that compared to the controls, the expression of miRNA-3070-3p was significantly increased and those of miRNA-7218-5p and miRNA-7219-5p were significantly decreased in the kidneys of a mouse model of renal interstitial fibrosis. This protocol can be used to determine the miRNA expression in the kidneys of mice with UUO.

Collapsibility of the Right Internal Jugular Vein Predicts Responsiveness to Fluid Administration in Patients Receiving Pressure Support Ventilation: A Prospective Cohort Study

Background

The aim of this study was to evaluate the utility of collapsibility of the internal jugular veins (IJVs) and subclavian veins (SCVs) in comparison with collapsibility of the inferior vena cava (IVC) in patients receiving pressure support ventilation.

Methods

Patients receiving pressure support ventilation were prospectively enrolled when fluid bolus administration was clinically indicated. The antero-posterior diameters of IJVs, SCVs and IVC were measured. Fluid responsiveness was defined as an 8% increase in stroke volume calculated with arterial pulse contour analysis after a passive leg raising maneuver.

Results

Twenty-seven patients (34 measurements) were included. Eighteen measurements were deemed fluid responsive. The area under the receiver operating characteristic curve of collapsibility of the right IJV antero-posterior diameter was 0.88 (95% confidence interval (CI): 0.75 - 0.99), while the area under the ROC curves for the antero-posterior diameter of the left IJV, right SCV, left SCV and the IVC were 0.57 (95% CI: 0.37 - 0.77), 0.61 (95% CI: 0.41 - 0.80), 0.55 (95% CI: 0.35 - 0.76) and 0.57 (95% CI: 0.37 - 0.77), respectively.

Conclusions

These results suggest that collapsibility of the right IJV is a useful predictor of fluid responsiveness in patients receiving pressure support ventilation. Collapsibility of the IVC did not predict fluid responsiveness in these patients.

Protective Effects of Diuretics Against the Development of Cardiovascular Disease in Patients with Chronic Kidney Disease: A Systematic Review

Cardiovascular disease is one of the most important risk factors for mortality and morbidity in patients with Chronic Kidney Disease (CKD). This systematic review focuses on the protective effects of diuretics against the development of cardiovascular disease in patients with CKD. Among various kinds of diuretics, spironolactone, a mineralocorticoid receptor antagonist, has been shown to have protective effects against cardiovascular disease in patients with all stages of CKD, including predialysis, hemodialysis, and peritoneal dialysis. Low-dose loop diuretics have also been shown to have cardioprotective effects in patients with CKD during the pre-dialysis and hemodialysis stages; however, high-dose loop diuretics have failed to show these cardioprotective effects. The protective effects of other classes of diuretics, including thiazide and tolvaptan, against cardiovascular diseases in patients with CKD remain unclear.

The Efficacy and Safety of Sodium-Glucose Cotransporter-2 Inhibitors in Patients with Advanced-Stage Diabetic Kidney Disease Taking Renin-Angiotensin System Blockers

INTRODUCTION AND OBJECTIVES

We investigated the efficacy and safety of sodium-glucose cotransporter-2 (SGLT-2) inhibitors as an add-on therapy in patients with advanced-stage diabetic kidney disease taking renin-angiotensin system (RAS) blockers.

MATERIALS AND METHODS

Changes in glycated hemoglobin (HbA1c), urine protein-to-creatinine ratio (UACR), body weight, systolic blood pressure, and annual change in estimated glomerular filtration rate (eGFR) were retrospectively analyzed in 20 patients after 12 months of SGLT-2 inhibitor administration (mean eGFR: 22.8 ± 9.7 mL/min/1.73 m2). All patients had advanced-stage diabetic kidney disease and were taking RAS blockers. Twenty patients matched with similar propensity scores who were not taking SGLT-2 inhibitors served as the control group.

RESULTS

The annual change in eGFR improved significantly from -8.6 ± 12.5 mL/min/1.73 m2/year to -2.6 ± 5.0 mL/min/1.73 m2/year after 12 months by SGLT-2 inhibitor administration (p < 0.05), but did not change in the control group. Other clinical parameters, such as HbA1c, UACR, body weight, blood pressure, serum lipids, and electrolytes did not change in either group. No adverse effects were observed by taking SGLT-2 inhibitors.

CONCLUSION

Using SGLT-2 inhibitors as an add-on therapy may have beneficial effects on renal function in patients with advanced-stage diabetic kidney disease taking RAS blockers without any adverse effects.

Successful treatment of cholesterol crystal embolism with anti-proprotein convertase subtilisin/kexin type 9 (PCSK9) antibody: a case report

Background

We report a unique case of renal cholesterol crystal embolism (CCE) induced by carotid artery stenting that was successfully treated with evolocumab, a fully human monoclonal antibody against proprotein convertase subtilisin kexin type 9 (PCSK9).

Case presentation

A 77-year-old man with hypertension, hyperlipidemia, and chronic kidney disease was referred to our department for decreased estimated glomerular filtration rate (eGFR)—from 32.0 to 13.9 mL/min/1.73 m²—5 weeks after carotid artery stenting. Further examination revealed livedo reticularis in the bilateral toes and eosinophilia (723/μL). Skin biopsy from livedo reticularis tissue in the bilateral toes showed cholesterol clefts in the small arteries. The patient was therefore diagnosed with CCE. After 25 weeks’ administration of evolocumab at a dose of 140 mg subcutaneously administered every 2 weeks, his eGFR had improved from 10.7 to 18.1 mL/min/1.73 m².

Conclusion

Evolocumab may have a beneficial effect on renal involvement in patients with CCE.

A case of posterior reversible encephalopathy syndrome in a patient undergoing automated peritoneal dialysis

A 44-year-old man undergoing automated peritoneal dialysis (PD) developed headache and dizziness with truncal ataxia and ataxic gait. Severe hypertension (systolic blood pressure/diastolic pressure: 193/83 mm Hg) and lower extremity edema were present, and his PD efficiency (weekly KT/V: 1.49) was inadequate. Magnetic resonance imaging revealed diffuse hyperintensities in the brain stem and bilateral cerebellar hemispheres on fluid-attenuated inversion recovery and apparent diffusion coefficient mapping imaging. Based on these findings, the patient was diagnosed with posterior reversible encephalopathy syndrome due to hypertension and uremia. He was treated with antihypertensive agents, and we changed the PD prescription to improve PD efficiency. Thereafter, his symptoms gradually improved, and abnormal findings on brain magnetic resonance imaging disappeared in accordance with lowering blood pressure.

Detection of microRNA Expression in the Kidneys of Immunoglobulin a Nephropathic Mice

Immunoglobulin A (IgA) nephropathy is a type of primary glomerulonephritis characterized by the abnormal deposition of IgA, leading to the end-stage renal failure. In recent years, the involvement of microRNAs (miRNAs) has been reported in the pathogenesis of IgA nephropathy. However, there is no established method for profiling miRNAs in IgA nephropathy using small animal models. Therefore, we developed a reliable method for analyzing miRNA in the kidney of an IgA mouse model (HIGA mouse). The goal of this protocol is to detect the altered expression levels of miRNAs in the kidneys of HIGA mice when compared with the levels in kidneys of control mice. In brief, this method consists of four steps: 1) obtaining kidney samples from HIGA mice; 2) purifying total RNA from kidney samples; 3) synthesizing complementary DNA from total RNA; and 4) quantitative reverse transcription polymerase chain reaction (qRT-PCR) of miRNAs. Using this method, we successfully detected the expression levels of several miRNAs (miR-155-5p, miR-146a-5p, and miR-21-5p) in the kidneys of HIGA mice. This new method can be applied to other studies profiling miRNAs in IgA nephropathy.

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 (&gt;65 years old) with age-dependent renal impairment (estimated glomerular filtration ratio &lt;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.

Cerebral oxygenation improvement is associated with hemoglobin increase after hemodialysis initiation

INTRODUCTION

Near-infrared spectroscopy has been used to measure the regional oxygen saturation (rSO₂) of the brain, and decreases in cerebral rSO₂ have been reported to lead to cognitive impairment in patients undergoing hemodialysis. However, reports about the association between changes in cerebral oxygenation and clinical parameters at hemodialysis initiation, including hemoglobin level, are lacking.

METHODS

This study included 33 patients at the hemodialysis initiation phase. Cerebral rSO2 was monitored using an INVOS 5100C. Included patients were assessed twice (at hemodialysis initiation and 42.7 ± 20.8 days after the first measurement), and changes in cerebral rSO2 were compared with changes in clinical parameters.

RESULTS

Cerebral rSO2 at the second measurement significantly increased compared with that at hemodialysis initiation (57.2 ± 6.8% vs 54.4 ± 8.8%, p < 0.05). Changes in cerebral rSO2 represented a significant correlation with changes in hemoglobin level, pulse rate, and serum albumin level. Multivariate linear regression analysis was performed using significant factors in simple linear regression analysis. Changes in hemoglobin (standardized coefficient: 0.37) and serum albumin (standardized coefficient: 0.45) levels were identified as independent factors influencing the changes in cerebral rSO2.

CONCLUSION

Cerebral rSO2 was low in the presence of low hemoglobin levels at hemodialysis initiation and improved in response to hemoglobin increase in addition to changes in serum albumin levels. Attention should be paid to changes in hemoglobin levels even at hemodialysis initiation to prevent the deterioration of cerebral oxygenation, and this might contribute to the maintenance of cognitive function in patients undergoing hemodialysis.

Longer-Period Effects of Bicarbonate/Lactate-Buffered Neutral Peritoneal Dialysis Fluid in Patients Undergoing Peritoneal Dialysis

High concentrations of lactate are considered to contribute to impairment of the peritoneal membrane. We investigated the longer-period effects of bicarbonate/lactate-buffered neutral peritoneal dialysis fluid (PDF) in patients undergoing PD for about 2 years. Patients undergoing PD were changed from a lactate-buffered neutral PDF to a bicarbonate/lactate-buffered neutral PDF. We then investigated the patients' clinical outcomes and peritoneal membrane functions as well as the surrogate markers in the drained dialysate. Fourteen patients undergoing PD were enrolled. Peritonitis was observed in one patient. No other adverse events were observed. Peritoneal function did not change as the ultrafiltration volume decreased. Fibrin degradation products and vascular endothelial growth factor in the drained dialysate decreased while the interleukin level increased. These results suggest that bicarbonate/lactate-buffered neutral PDF may have beneficial effects in terms of peritoneal preservation and can be safely used in patients undergoing PD.

Successful treatment of nonocclusive mesenteric ischemia after aortic valve replacement with continuous arterial alprostadil infusion: A case report

INTRODUCTION

Nonocclusive mesenteric ischemia (NOMI) after surgery has an extremely poor prognosis with a mortality rate of 30-100%. We report a patient with NOMI following aortic valve replacement who failed to improve despite continuous intra-arterial infusion of papaverine, but was successfully treated with alprostadil (prostaglandin E1 [PGE1]) infusion.

PRESENTATION OF CASE

The patient is a 77-year-old man who underwent aortic valve replacement. Due to elevated serum lactate levels five hours after intensive care unit admission, superior mesenteric arteriography was performed, establishing the diagnosis of NOMI. Although continuous intra-arterial infusion of papaverine was begun, lactate levels remained elevated. Repeat angiography and laparotomy revealed extensive ischemic changes of the intestine. The vasodilator was changed to PGE1, which improved arterial spasm. The patient ultimately needed an ileocecal resection, but the extent of the resection was limited with concomitant PGE1 administration.

DISCUSSION

In the present patient, although NOMI was unresponsive to appropriate treatment including intra-arterial infusion of papaverine, continuous intra-arterial infusion of PGE1 salvaged most of the intestine.

CONCLUSIONS

In a patient with recurrent NOMI despite appropriate treatment including intra-arterial infusion of papaverine, continuous intra-arterial infusion of PGE1 may limit the extent of intestinal resection needed. Continuous intra-arterial infusion of PGE1 may be a useful treatment for patients with refractory NOMI.

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.

A Quantitative Detection Method for MicroRNAs in the Kidney of an Ischemic Kidney Injury Mouse Model

MicroRNAs (miRNAs) are involved in various disease states and are effective biomarkers for the early diagnosis of diseases and treatment in mice. However, standard protocols for the purification of miRNAs and detection of their expression in the kidneys of acute kidney injury (AKI) mice have not been well established. This study developed an effective and simple protocol to purify and quantify miRNAs in the kidneys of an AKI mouse model induced by renal ischemia-reperfusion using quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR). This protocol comprises five steps: 1) induction of AKI by renal ischemia-reperfusion, 2) harvesting of kidneys, 3) purification of total RNA, including miRNAs, from kidneys, 4) cDNA synthesis by reverse transcription of miRNA, and 5) qRT-PCR to detect miRNA expression. Using this protocol, the renal ischemia-reperfusion injury model can be generated with mild to severe forms of AKI. Additionally, if the procedure is followed properly, a consistent AKI model with minimal individual differences can be obtained. This qRT-PCR assay shows a very wide dynamic range and enables the discrimination of mature miRNAs, which can be accurately quantified with high specificity. This protocol can be used to study the miRNA expression profile in AKI kidneys.