A comparison of the utility of the urine dipstick and urine protein-to-creatinine ratio for predicting microalbuminuria in patients with non-diabetic lifestyle-related diseases -a comparison with diabetes.

BACKGROUND: The utility of dipstick proteinuria for predicting microalbuminuria in non-diabetic lifestyle-related diseases compared with the urine protein-to-creatinine ratio (uPCR) and the effect of dipstick proteinuria on the cut-off value (CO) and accuracy of uPCR are unclear. METHODS: The subjects included Japanese patients ≥ 18 years old with lifestyle-related diseases who had an estimated glomerular filtration rate of ≥ 15 ml/min/1.73 m2 and uPCR of < 0.5 g/gCr at initiation. Urine dipstick, uPCR and urine albumin-to-creatinine ratio (uACR) were measured three times per case. Microalbuminuria was defined as uACR of 30-299 mg/gCr for at least 2 of 3 measurements. Youden's Index was used as the optimal CO. Factors associated with microalbuminuria were analyzed using a logistic regression model. RESULTS: In 313 non-diabetic cases (median 70.8 years old), 3 dipstick proteinuria measurements were independently useful for detecting microalbuminuria, and the CO was set when a trace finding was obtained at least 1 of 3 times (sensitivity 0.56, specificity 0.80, positive predictive value [PPV] 0.73, negative predictive value [NPV] 0.65). A single uPCR measurement was more useful than 3 dipstick measurements, and was useful for detecting microalbuminuria even in cases with three consecutive negative proteinuria findings, indicating that the CO of the second uPCR with G1-3a (n = 136) was 0.06 g/gCr (sensitivity 0.76, specificity 0.84. PPV 0.68, NPV 0.89), while that with G3-b4 (n = 59) was 0.10 g/gCr (sensitivity 0.56, specificity 0.91. PPV 0.83, NPV 0.71). The sum of 3 uPCRs was useful for detecting microalbuminuria in cases with G1-3a (sensitivity 0.67, specificity 0.94, PPV 0.82, NPV 0.86) and G3b-4 (sensitivity 0.78, specificity 0.94, PPV 0.91 NPV 0.83), with both COs being 0.23 g/gCr. These COs of microalbuminuria did not change when trace or more proteinuria was included, although the sensitivity increased. A high uPCR and low urine specific gravity or creatinine level were independent factors for uACR ≥ 30 mg/gCr in cases with negative proteinuria, although the uPCR was a major predictive factor of a uACR ≥ 30 mg/gCr. CONCLUSIONS: The uPCR (preferably determined using early-morning urine), including in dipstick-negative proteinuria cases with non-diabetic lifestyle-related diseases, can aid in the early detection of microalbuminuria. TRIAL REGISTRATION: Retrospectively registered.

Prediction of microalbuminuria from proteinuria in chronic kidney disease due to non-diabetic lifestyle-related diseases: comparison with diabetes.

BACKGROUND: To suppress increases in kidney failure and cardiovascular disease due to lifestyle-related diseases other than diabetes, early intervention is desirable. We examined whether microalbuminuria could be predicted from proteinuria. METHODS: The participants consisted of adults who exhibited a urinary protein-to-creatinine ratio (uPCR) of < 0.5 g/gCr and an eGFR of ≥ 15 ml/min/1.73 m2 in their spot urine at their first examination for lifestyle-related disease. Urine was tested three times for each case, with microalbuminuria defined as a urinary albumin-to-creatinine ratio (uACR) of 30-299 mg/gCr, at least twice on three measurements. Youden's Index was used as an index of the cut-off value (CO) according to the ROC curve. RESULTS: A single uPCR was useful for differentiating normoalbuminuria and micro- and macroalbuminuria in patients with non-diabetic lifestyle-related diseases. Regarding the GFR categories, the CO of the second uPCR was 0.09 g/gCr (AUC 0.89, sensitivity 0.76, specificity 0.89) in G1-4 (n = 197) and 0.07 g/gCr (AUC 0.92, sensitivity 0.85, specificity 0.88) in G1-3a (n = 125). Using the sum of two or three uPCR measurements was more useful than a single uPCR for differentiating microalbuminuria in non-diabetic lifestyle disease [CO, 0.16 g/gCr (AUC 0.91, sensitivity 0.85, specificity 0.87) and 0.23 g/gCr (AUC 0.92, sensitivity 0.88, specificity 0.84), respectively]. CONCLUSION: Microalbuminuria in Japanese individuals with non-diabetic lifestyle-related diseases can be predicted from the uPCR, wherein the CO of the uPCR that differentiates normoalbuminuria and micro- and macroalbuminuria was 0.07 g/gCr for G1-3a, while that in G3b-4 was 0.09 g/gCr.

Effect of AST-120 on Endothelial Dysfunction in Adenine-Induced Uremic Rats.

Aim. Chronic kidney disease (CKD) represents endothelial dysfunction. Monocyte adhesion is recognized as the initial step of arteriosclerosis. Indoxyl sulfate (IS) is considered to be a risk factor for arteriosclerosis in CKD. Oral adsorbent AST-120 retards deterioration of renal function, reducing accumulation of IS. In the present study, we determined the monocyte adhesion in the adenine-induced uremic rats in vivo and effects of AST-120 on the adhesion molecules. Methods. Twenty-four rats were divided into control, control+AST-120, adenine, and adenine+AST-120 groups. The number of monocytes adherent to the endothelium of thoracic aorta by imaging the entire endothelial surface and the mRNA expressions of adhesion and atherosclerosis-related molecules were examined on day 49. The mRNA expressions of ICAM-1 and VCAM-1 in human umbilical vein endothelial cells were also examined. Results. Adenine increased the number of adherent monocytes, and AST-120 suppressed the increase. The monocyte adhesion was related to serum creatinine and IS in sera. Overexpression of VCAM-1 and TGF- ß 1 mRNA in the arterial walls was observed in uremic rats. IS induced increase of the ICAM-1 and VCAM-1 mRNA expressions in vitro. Conclusion. It appears that uremic condition introduces the monocyte adhesion to arterial wall and AST-120 might inhibit increasing of the monocyte adherence with CKD progression.

Suppressive effects of iron overloading on vascular calcification in uremic rats.

BACKGROUND: Medial vascular calcification is a specific complication in chronic kidney disease (CKD) patients although its pathogenesis is poorly understood. The administration of iron (Fe), generally used for the treatment of anemia in CKD patients, induces oxidative stress. Fe loading possibly affects the progress of vascular calcification in uremia. We investigated the effect of Fe on vascular calcification and its mechanism in uremic rats. METHOD: Thirty-two rats were divided into four groups: untreated rats (controls), rats fed a standard diet with Fe administration (Fe group), rats fed an adenine-enriched diet (uremic group), and rats fed an adenine-enriched diet with Fe administration (uremic + Fe group). Iron dextran was administered once a week for 5 weeks intraperitoneally. Morphological alterations and vascular calcification-associated factors in the aortic wall were evaluated. RESULTS: No aortic calcification was observed in the control group although uremic rats developed severe vascular calcification. Fe loading suppressed vascular calcification in the uremic groups. Expressions of runt-related transcription factor 2 (Runx2), single-strand (ss)DNA and phosphate transporter (Pit)-1 were increased in the uremic rats compared to the control rats. In the uremic group, Fe administration did not show any effect on ssDNA expression, but reduced Runx2 and Pit-1 expressions. CONCLUSION: Fe suppressed the development of vascular calcification through the prevention of Pit-1 and vascular smooth muscle cell osteoblastic transdifferentiation.

Predictive factors associated with change rates of LV hypertrophy and renal dysfunction in CKD patients.

BACKGROUND: This longitudinal study is the first report on the factors associated with change rates of the estimated glomerular filtration rate (eGFR) and left ventricular mass index (LVMI) using echocardiography in chronic kidney disease (CKD) patients. METHODS: Measurements of biochemical and physical values, and LVMI evaluated by echocardiography were performed twice (baseline and follow-up period) in pre-dialysis CKD patients. Blood and urine samples were collected at the time of the echocardiographic study. RESULTS: The change rates of hemoglobin (Hb) and transferrin saturation (TSAT: (serum iron/total iron binding capacity)) were identified as independent risk factors for changes in eGFR by multivariate regression analysis. In the LVMI improvement group, the change rate of systolic blood pressure (sBP) was identified as an independent factor for change in LVMI. In the LVMI worsening group, the change rates of sBP, proteinuria and Hb were identified as independent risk factors for changes in LVMI. CONCLUSIONS: It appears that treatment of renal and iron deficiency anemia might prevent progression of renal dysfunction. To prevent LV hypertrophy in CKD patients, renal anemia, hypertension and proteinuria should be treated.

Risk factors associated with increased left ventricular mass index in chronic kidney disease patients evaluated using echocardiography.

BACKGROUND: It is still not clear which factors are associated with left ventricular mass index (LVMI) in chronic kidney disease (CKD) patients, based on the patient's physical and biochemical parameters at the time of echocardiography. The objective of the present study was to identify factors associated with LVMI in CKD patients (predialysis patients), using echocardiography. METHODS: Physical, biochemical and LVMI data evaluated by echocardiography were retrospectively analyzed in 930 CKD patients in Juntendo University Hospital, Tokyo, Japan. RESULTS: Levels of systolic blood pressure (SBP) and hemoglobin (Hb) were independent risk factors for increased LVMI in multivariate regression analysis. SBP was significantly correlated with LVMI (r=0.314, p<0.0001). The level of Hb was inversely correlated with LVMI (r=-0.372, p<0.0001). LVMI increased with decreasing renal function. SBP was significantly higher in patients with left ventricular hypertrophy (LVH) in CKD stages 2 and 5, and Hb was significantly lower in patients with LVH in stages 4 and 5 than in the group without LVH. CONCLUSIONS: It is important to treat hypertension and anemia to prevent LVH in CKD patients. These findings have some therapeutic implications for treatment strategies for predialysis patients.

Autophosphorylation profiling of Arabidopsis protein kinases using the cell-free system.

Protein phosphorylation is one of the main process in the signal transduction pathway. In recent years, there has been increasing attention to plant phosphorylation signaling and many laboratories are trying to elucidate pathways using various approaches. Although more than 1000 protein kinase (PK) genes have been annotated in the Arabidopsis genome, biochemical characterization of those PKs is limited. In this work, we demonstrate high-throughput profiling of serine/threonine autophosphorylation activity by a combination of the 759N-terminal biotinylated proteins library, produced using a wheat germ cell-free protein production system, and a commercially available luminescence system. Luminescent analysis revealed that 179 of the 759 PKs had autophosphorylation activity. From these 179 PKs, 67 of the most active PKs were analyzed to determine their function using the PlantP database. This analysis revealed that 35 (53%) of the proteins were classified as non-transmembrane protein kinases, and 15 (23%) were receptor-like protein kinases. Additionally, PKs from Group 4.4-MAP3K, Group 1.6, Group 4.5-MAPK/CDC/CK2/GSK kinases and Group 1.10-receptor like cytoplasmic kinases contained the highest percentage of autophosphorylated activity. Next, to get a better overview of the annotated 67 PKs, we used the gene ontology annotation search on the TAIR website to classify the 67 PKs into functional category. As a result, some of these PKs may be involved in phospho-signaling pathways such as signal transduction, stress response, and the regulation of cell division. Information from this study may shed light on many unknown plant PKs. This study will be a basis for understanding the function of PKs in phosphorylation network for future research.