Sodium-glucose cotransporter-2 inhibitors increase urinary tract infections?-a cross sectional analysis of a nationwide Japanese claims database.

Sodium-glucose cotransporter-2 (SGLT2) inhibitors are a novel class of antidiabetic drugs. Guidelines for the proper use of SGLT2 inhibitors recommend caution regarding urinary tract infections (UTIs). However, little evidence has been reported on the relationship between SGLT2 inhibitors and UTIs in large epidemiological studies. We investigated (1) the relationship between diabetes mellitus (DM) and UTIs and (2) the relationship between SGLT2 inhibitor prescriptions and the likelihood of developing UTIs in patients with DM, using a nationwide Japanese health insurance claims database by MDV analyzer®. We found that the incidence of UTIs was significantly higher among patients with DM than among those without DM (odds ratio (OR), 1.71; 95% confidence interval (CI), 1.69-1.72, for male; OR, 1.90; 95% CI, 1.89-1.92 for female). In contrast, in male patients with DM, the prescription of SGLT2 inhibitors was negatively associated with the likelihood of developing UTIs (OR, 0.74; 95% CI, 0.72-0.75). Among female patients with DM, there was no significant difference in the incidence of UTIs with or without an SGLT2 inhibitor prescription (OR, 0.99; 95% CI, 0.96-1.01). Subgroup analyses by age confirmed similar relationships between SGLT2 inhibitor prescriptions and UTIs, except for female patients aged ≤39 years, in whom SGLT2 inhibitor prescription was negatively associated with the likelihood of developing UTIs. In conclusion, our analysis of a nationwide claims database found no evidence that SGLT2 inhibitors increase UTIs in Japanese patients with DM, regardless of sex or age.

Inhibition of sodium-glucose cotransporter 2 suppresses renal stone formation.

BACKGROUND AND AIMS: Nephrolithiasis is a common renal disease with no effective medication. Sodium-glucose cotransporter-2 (SGLT2) inhibitors, an anti-diabetic agent, have diuretic and anti-inflammatory properties and could prevent nephrolithiasis. Here, we investigated the potential of SGLT2 inhibition against nephrolithiasis using large-scale epidemiological data, animal models, and cell culture experiments. METHODS: This study included the data of diabetic patients (n = 1,538,198) available in the Japanese administrative database and divided them according to SGLT2 inhibitor prescription status. For animal experiments, renal calcium oxalate stones were induced by ethylene glycol in Sprague-Dawley rats, and phlorizin, an SGLT1/2 inhibitor, was used for the treatment. The effects of SGLT2-specific inhibition for renal stone formation were assessed in SGLT2-deficient mice and a human proximal tubular cell line, HK-2. RESULTS: Nephrolithiasis prevalence in diabetic men was significantly lower in the SGLT2 inhibitor prescription group than in the non-SGLT2 inhibitor prescription group. Phlorizin attenuated renal stone formation and downregulated the kidney injury molecule 1 (Kim1) and osteopontin (Opn) expression in rats, with unchanged water intake and urine volume. It suppressed inflammation and macrophage marker expression, suggesting the role of the SGLT2 inhibitor in reducing inflammation. SGLT2-deficient mice were resistant to glyoxylic acid-induced calcium oxalate stone formation with reduced Opn expression and renal damages. High glucose-induced upregulation of OPN and CD44 and cell surface adhesion of calcium oxalate reduced upon SGLT2-silencing in HK-2 cells. CONCLUSION: Overall, our findings identified that SGLT2 inhibition prevents renal stone formation and may be a promising therapeutic approach against nephrolithiasis.

Safety of peritoneal dialysis catheter surgery under dexmedetomidine and local anesthesia for elderly patients in Japan: a single-center prospective cohort study.

BACKGROUND: The number of patients aged ≥ 75 years and who need renal replacement therapy is steadily increasing. The study aimed to determine the safety of open surgery for peritoneal dialysis (PD) catheter placement in such patients. METHODS: This prospective cohort study included patients who underwent PD catheter placement by open surgery under dexmedetomidine (DEX) and local anesthesia at our institution from January 2015 to February 2021. Patients were divided into the following two groups according to age at the time of surgery: ≥ 75 years (group A) and < 75 years (group B). We compared the perioperative and postoperative complications (i.e., time to the first PD-related peritonitis and catheter obstruction requiring surgical intervention within 1 year) between the groups. RESULTS: A total of 118 patients were categorized into groups A (n = 65) and B (n = 53). No significant intergroup differences were observed in the postoperative fever, total duration of surgery, perioperative hemoglobin decrease, changes in the white blood cell count and C-reactive protein, postoperative catheter leakage, postoperative hospital stay, time to the first PD-related peritonitis, and catheter obstruction requiring surgical intervention within 1 year. CONCLUSIONS: The surgery for PD catheter placement by open surgery under DEX and local anesthesia in elderly patients is safe and effective.

Impact of preoperative factors on catheter position in peritoneal dialysis: a prospective cohort study.

BACKGROUND: Peritoneal dialysis (PD) catheter malposition is one of the complications of renal replacement therapy. This study aimed to determine the preoperative factors that cause PD catheter malposition. METHODS: The prospective cohort study included patients who underwent PD catheter insertion surgery and had preoperative and postoperative computed tomography scans. We compared preoperative and intraoperative factors between the lower depth catheter group (group L) and upper depth catheter group (group U), and preoperative and intraoperative factors between the posterior catheter group (group P) and anterior catheter group (group A). In addition, PD catheter obstruction requiring surgical intervention in each group was followed up for 1 year. RESULTS: A total of 150 patients were categorized into groups L (n = 77) and U (n = 73), or groups P (n = 107) and A (n = 43). Body mass index (BMI; P = 0.02), subcutaneous fat area (P = 0.02), and rate of previous abdominal surgery (P = 0.01) were significantly lower in group L than in group U. In terms of anterior catheter position, females had more-anterior catheter positions. The time to PD catheter obstruction requiring surgical intervention (P = 0.03) was significantly lower in group U than in group L. CONCLUSIONS: High BMI, high subcutaneous fat area, high subcutaneous fat thickness, and previous abdominal surgery were identified as preoperative factors that cause the PD catheter to have an upper depth. Female sex was a preoperative influencing factor for the anterior PD catheter position.

The Impact of Preoperative Risk Factors on Peritoneal Dialysis-Related Peritonitis: A Single-Center Prospective Study in Japan.

Background and Objectives: Peritoneal dialysis (PD)-related peritonitis is a critical problem. However, preoperative risk factors for PD-related peritonitis have not been established. Thus, we aimed to determine the preoperative risk factors for PD-related peritonitis. Materials and Methods: This is a single-center prospective observational study. All peritonitis episodes during the study period were recorded, and preoperative and intraoperative clinical parameters were compared between patients with and without peritonitis to examine risk factors for PD-related peritonitis. Furthermore, subcutaneous and abdominal fat volumes were evaluated using computed tomography. Results: Among a total of 118 patients, 24 patients developed peritonitis. The proportion of male patients (83% vs. 61%, p = 0.04), body mass index (25 vs. 22 kg/m2, p = 0.04), and subcutaneous fat area (120 vs. 102 cm2, p = 0.01) were significantly higher and the proportion of patients living with family members (75% vs. 94%, p = 0.02) was significantly lower in the peritonitis group than in the non-peritonitis group. There were no significant differences in age, operation method, surgeon experience, previous abdominal surgery, medical history of diabetic nephropathy, serum albumin level, and renal function between the two groups. Conclusions: Male patients with high subcutaneous fat who are living alone might be at higher risk of PD-related peritonitis. These characteristics might be useful in risk assessment and patient education before PD induction.

Elevated (Pro)renin Receptor Expression by Anti-Cancer Drugs, Carboplatin and Paclitaxel, in Cultured Cancer Cells: Possible Involvement of Apoptosis and Autophagy.

(Pro)renin receptor [(P)RR] is a component of the renin-angiotensin system and plays an essential role in the activity of vacuolar H+-ATPase and autophagy. (P)RR is expressed in cancer cells. However, the relationship among (P)RR, apoptosis and autophagy in the treatment of anti-cancer drugs has not been clarified. The aim of this study was to clarify the effects of anti-cancer drugs with autophagy-promoting activity on (P)RR expression in cancer cells. MCF-7 breast cancer cells and A549 lung cancer cells were treated with carboplatin or paclitaxel, and the expression of (P)RR, apoptosis markers and autophagy markers were assessed by RT-qPCR, western blot analysis and immunocytochemistry. Expression levels of (P)RR mRNA and soluble (P)RR protein were increased by carboplatin or paclitaxel in a dose-dependent manner. Immunofluorescence staining of (P)RR was increased in both MCF-7 and A549 cells treated by carboplatin or paclitaxel. Apoptosis induction was shown by elevated BAX/BCL2 mRNA levels and increased active caspase3-positive cells. Moreover, autophagy induction was confirmed by increased levels of autophagy-associated mRNAs and LC3B-II proteins. (P)RR knockdown by (P)RR-specific siRNA suppressed the cell viability in MCF-7 cells and A549 cells under the treatment of carboplatin or paclitaxel, suggesting that (P)RR deficiency inhibits the proliferation of cancer cells in a pathway different from carboplatin or paclitaxel. The present study showed that the expression of (P)RR mRNA and soluble (P)RR was increased by anti-cancer drugs with autophagy-promoting activity. Upregulated (P)RR and autophagy may constitute a stress adaptation that protects cancer cells from apoptosis.

Low-energy extracorporeal shock wave ameliorates ischemic acute kidney injury in rats.

BACKGROUND: Low-energy extracorporeal shock wave (SW) improves ventricular function in ischemic cardiomyopathy through the upregulation of vascular endothelial growth factor (VEGF). VEGF is known to play important roles in acute kidney injury (AKI), and the present study investigates the efficacy of SW for AKI by renal ischemia-reperfusion (I/R) injury. METHODS: Male 8-week-old Sprague-Dawley rats were divided into the following groups: SW-treated I/R group (I/R-SW), untreated I/R group (I/R), and Sham group. To induce I/R, the left renal pedicles were clamped for 45 min. The I/R-SW group was treated with SW to both kidneys on the immediate postoperative period (day 0), days 1, 2, 7, 8, 9, 14, 15, and 16. Rats were killed on day 2 and day 20 to determine histology, renal function, and Vegf family mRNA expression. RESULTS: Plasma creatinine on day 2 was significantly lower in the I/R-SW group than in the I/R group. Light microscopy revealed significantly lower tubular injury scores for the outer medulla in the I/R-SW group than in the I/R group. Podoplanin-positive lymphatic vessels were significantly increased in the left (affected side) outer medulla in the I/R-SW group on day 20. The expression levels of Vegf in the right (intact side) cortex were significantly higher in the I/R-SW group than in the I/R group on day 2. CONCLUSION: Shock wave ameliorated renal tubular injury and renal function in AKI model, through the stimulation of Vegf family expression and lymphangiogenesis. SW may be effective as a non-invasive treatment for ischemic AKI.

Hydrochlorothiazide ameliorates polyuria caused by tolvaptan treatment of polycystic kidney disease in PCK rats.

BACKGROUND: Tolvaptan is an effective treatment for polycystic kidney disease (PKD), but also causes unfortunate polyuria. Hydrochlorothiazide (HCTZ) has been shown to reduce urine volume in nephrogenic diabetes insipidus, raising the possibility that HCTZ could also be effective in reducing tolvaptan-induced polyuria. In this study, we examined the combined administration of HCTZ and tolvaptan. METHODS: Male PCK rats were divided into four groups of normal chow (Cont), normal chow plus tolvaptan, gavage HCTZ treatment, and tolvaptan + HCTZ. Biochemical examinations of the plasma and urine were performed as well as histological and molecular (mRNA and protein expression) analyses. RESULTS: Groups treated with tolvaptan had significantly higher 24 h urine excretion, which was significantly reduced in the tolvaptan + HCTZ group after 2 weeks. Cyst size, pERK protein expression, and Cyclin D1 mRNA expression were all significantly reduced in both the tolvaptan and tolvaptan + HCTZ groups, indicating that HCTZ did not affect the beneficial functions of tolvaptan. Notably, aquaporin 2 redistribution from the apical to intracellular domains was observed in tolvaptan-treated rats and was partially reversed in the tolvaptan + HCTZ group. The renal glomerular filtration rate was reduced in the tolvaptan + HCTZ group. Significantly lowered mRNA expression of neuronal nitric oxide synthase, prostaglandin E synthase 2 and renin were also found in the medulla, but not in the cortex. CONCLUSION: HCTZ reduces tolvaptan-induced polyuria without altering its beneficial effects on PKD. This novel therapeutic combination could potentially lead to better PKD treatments and improved quality of life for the affected patients.

Better Healing of the Exit Site with Negative-Pressure Wound Therapy.

Exit-site infection poses a risk for peritonitis and can shorten peritoneal dialysis (PD) vintage. A loose fit of the skin around the catheter at the exit site can push bacteria surrounding the catheter into the subcutaneous tunnel. Negative-pressure wound therapy (NPWT) has been used to hasten healing of the wound after an operation or to treat pressure ulcers. We hypothesized that NPWT could speed the healing of the exit site and tighten the fit of the skin around the catheter. Using a V.A.C. Therapy system [vacuum-assisted closure (KCI, San Antonio, TX, U.S.A.)], NPWT was therefore applied in 9 patients for 1 - 2 weeks after the PD catheter insertion operation. Results in those patients were compared with results in patients who did not receive NPWT.The healed exit site was classified as either tightly fitted (when the skin was tightly connected around the PD catheter) or loosely fitted (when the skin was not tightly connected around the catheter). The relevant data were retrieved from the medical record and analyzed retrospectively.Patients who received NPWT had a tight exit site after 1 - 2 weeks. Those who did not receive NPWT did not have a tight exit site after 1 - 2 weeks. No bleeding was observed in patients receiving NPWT. Bleeding from the exit site after the catheter insertion operation was observed in 3 patients not receiving NPWT.Because we use a fine trocar to make the subcutaneous catheter tunnel, bleeding from the vasculature can often be observed. That bleeding could be minimized with the application of NPWT. Negative pressure could also hasten wound healing and result in a tight fit of the skin around the catheter within in 1 - 2 weeks compared with the 1 month typically required with the use of conventional film dressings.Negative-pressure wound therapy is beneficial for creating a tight fit of the skin to the catheter within 1 - 2 weeks and might reduce the number of exit-site and tunnel infections, which could result in a reduction in the peritonitis rate.

Diuretic usage for protection against end-organ damage in liver cirrhosis and heart failure.

Volume overload is common in liver cirrhosis, heart failure, and chronic kidney disease, being an independent risk factor for mortality. Loop diuretics have been widely used for treating volume overload in these patients. However, there is a tendency to increase the dose of loop diuretics partly because of diuresis resistance. Neurohormonal factors are also enhanced in these patients, which play a role in volume overload and organ ischemia. Loop diuretics cannot improve neurohormonal factors and could result in end-organ damage. The water diuretic tolvaptan has been approved for use for volume overload in heart failure and liver cirrhosis. Despite causing similar increases in urine volume, its characteristics differ from those of loop diuretics. Renal blood flow is maintained with tolvaptan but decreased with furosemide in heart failure patients. Neurohormonal factors and blood pressure are not markedly altered by tolvaptan administration. It is expected that these mechanisms of tolvaptan can protect against worsening renal function by volume overload diseases compared with loop diuretics. It has also been reported that some patients do not respond well to tolvaptan. Loop diuretics and tolvaptan share the same mechanism with regard to decreasing renal interstitial osmolality, which plays a fundamental role in water diuresis. Thus, a high dose of loop diuretics could result in resistance to tolvaptan, so tolvaptan should be administered before increasing the loop diuretic dose. Therefore, volume control without enhancing end-organ damage can be achieved by adding tolvaptan to a tolerable dose of Na-sparing diuretics.

Urinary angiotensinogen excretion is associated with blood pressure in obese young adults.

Intrarenal RAS has been suggested to be involved in the pathogenesis of hypertension. It was recently reported that urinary angiotensinogen excretion levels are associated with intrarenal RAS. However, few markers predicting intrarenal RAS have been investigated in obese young subjects. The present study evaluated the association between blood pressure and intrarenal RAS activity, inflammation and oxidative stress in obese young adults. Urinary angiotensinogen excretion and urinary monocyte chemotactic protein (MCP)-1, and urinary thiobarbituric acid reaction substance (TBARS) as markers of intrarenal RAS activity, inflammation, and oxidative stress, respectively, were determined from morning urine of 111 young male adults. Participants were divided into two groups based on the body mass index (BMI). Natural log-transformed urinary angiotensinogen excretion level was significantly associated with blood pressure, MCP-1 excretion, and TBARS excretion elevation in the obese group (BMI ≥25 kg/m(2)). Multivariable analyses showed that every 1 standard deviation increase in natural-log transformed urinary angiotensinogen and MCP-1 excretion, but not TBARS excretion level was associated with elevated blood pressure in the obese group. These results indicate that urinary angiotensinogen and MCP-1 excretion were associated with blood pressure elevation in this population of obese young adults. It suggested that inappropriate RAS activity and inflammation precedes hypertension in obese young subjects and urinary angiotensinogen could be a screening maker for hypertension in young obese subjects.

Efficacy and Biocompatibility of Neutral Icodextrin Peritoneal Dialysis Fluid.

Neutral icodextrin peritoneal dialysis (PD) fluid (n-ICO) has become available for use in Japan. However, removal of water and solutes remains to be elucidated in detail. The present study was designed to determine removal of water, electrolytes, and small, middle, and large molecules in a period of 16 hours. In addition, biocompatibility with respect to peritoneal mesothelial cells was determined.Three stable patients undergoing PD at Tohoku University Hospital were administered n-ICO. Water removal was monitored every 2 hours. Sodium, urea nitrogen [molecular weight (MW): 28 Da], uric acid (MW: 168 Da), ß2-microglobulin [ß2M (MW: 11,800 Da)], α1-microglobulin [α1M (MW: 33,000 Da)], albumin (MW: 66,000 Da), and immunoglobulin G (MW: 160,000 Da) were measured in plasma and dialysate.Primary human peritoneal mesothelial cells were collected from 6 patients. Equal numbers of cells were seeded into 96-well culture plates and cultured for 12 hours. Culture medium was then replaced with dialysate, and 24-hour cell proliferation was determined by WST-1 assay.Water removal was sustained for 16 hours with n-ICO. The Na concentration in effluent did not change over that time. Small molecules such as urea nitrogen and uric acid were rapidly removed. Thus, their dialysate-to-plasma concentration ratio (D/P) approached 1.0 (equilibrium) in 2 - 4 hours. The D/P values for the larger molecules ß2M and α1M were 0.4 and less than 0.1 respectively at 16 hours. However, larger molecules were removed in a time-dependent manner.Cell proliferation with n-ICO PD fluid was not different from that with lactate-buffered glucose PD fluid, but was increased from that with acidic icodextrin PD fluid (a-ICO).Water and solute removal with the new n-ICO is not much different from that with a-ICO. However, biocompatibility as reflected by cell proliferation was superior under n-ICO than under a-ICO and equal to proliferation under glucose PD fluid.

Role of Chronic Use of Tolvaptan in Patients with Heart Failure Undergoing Peritoneal Dialysis.

In the present study, we assessed the effect of chronic tolvaptan treatment and compared it with the effect of conventional treatment without tolvaptan. In addition, changes in cardiac load and body fluid composition were compared.The study enrolled 22 patients undergoing peritoneal dialysis who had been receiving tolvaptan for more than 1 year and 10 patients undergoing peritoneal dialysis who had been treated with conventional diuretics. Left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF), and E/e' index were measured by echocardiography at baseline and after 12 months of tolvaptan treatment (or an equivalent period). Body composition was analyzed by bioimpedance monitoring (BIM).In the tolvaptan group, LVMI was significantly reduced after 12 months of treatment; in the conventional-treatment group, it was significantly increased. The measured LVEF did not change in the tolvaptan group, but it increased significantly in the conventional-treatment group. The E/e' index was not altered in either group; however, it was reduced in patients receiving tolvaptan whose initial E/e' was greater than 15. Although urine volume was not significantly increased in either group, renal creatinine clearance increased significantly in tolvaptan group; no change was observed in the conventional-treatment group. Renal and peritoneal Kt/V did not significantly change during the study. In both groups, ß2-microglobulin was significantly and similarly increased. Extracellular water (ECW) and intracellular water (ICW) as determined by BIM were both reduced after 12 months of tolvaptan treatment. We observed a significant correlation between the ratio of ECW to total body water at the initiation of tolvaptan and the reduction in ECW after 12 months.Our results indicate that chronic tolvaptan treatment has a beneficial role in body fluid control without a reduction in cardiac and renal function. Volume control depends on an equal reduction in ECW and ICW, which can also have a benefit in avoiding hyponatremia.

Reactive oxygen species as important determinants of medullary flow, sodium excretion, and hypertension.

The physiological evidence linking the production of superoxide, hydrogen peroxide, and nitric oxide in the renal medullary thick ascending limb of Henle (mTAL) to regulation of medullary blood flow, sodium homeostasis, and long-term control of blood pressure is summarized in this review. Data obtained largely from rats indicate that experimentally induced elevations of either superoxide or hydrogen peroxide in the renal medulla result in reduction of medullary blood flow, enhanced Na(+) reabsorption, and hypertension. A shift in the redox balance between nitric oxide and reactive oxygen species (ROS) is found to occur naturally in the Dahl salt-sensitive (SS) rat model, where selective reduction of ROS production in the renal medulla reduces salt-induced hypertension. Excess medullary production of ROS in SS rats emanates from the medullary thick ascending limbs of Henle [from both the mitochondria and membrane NAD(P)H oxidases] in response to increased delivery and reabsorption of excess sodium and water. There is evidence that ROS and perhaps other mediators such as ATP diffuse from the mTAL to surrounding vasa recta capillaries, resulting in medullary ischemia, which thereby contributes to hypertension.

A functional (pro)renin receptor is expressed in human lymphocytes and monocytes.

The renin-angiotensin system (RAS) is involved in inflammation. The signaling via the ANG II type 1 receptor in human lymphocytes and monocytes, which play key roles in pathophysiology of glomerulonephritis (GN), can enhance inflammation. However, the role of the (pro)renin receptor [(P)RR], a component of the RAS, in inflammatory reactions is unknown. We assessed whether (P)RR is expressed in human lymphocytes and monocytes by RT-PCR, Western blotting, flow cytometry, and immunohistochemistry, and whether (P)RR functions in inflammation. (P)RR mRNA and protein were expressed in human peripheral blood mononuclear cells (PBMCs). Flow cytometric analysis revealed high expression of (P)RR on monocytes. (P)RR was present on PBMCs, infiltrating lymphocytes, and macrophages around glomeruli with a crescent in anti-neutrophil cytoplasmic antibody (ANCA)-associated GN. Renin stimulation of PBMCs from healthy subjects in the presence of the ANG II type 1 receptor and ANG II type 2 receptor blockers induced ERK1/2 phosphorylation and release of IL-6 and expression of cyclooxygenase-2 (COX-2). The increases in cytokine release and COX-2 expression were inhibited in the presence of an ERK1/2 inhibitor. (P)RR knockdown by small interfering RNA in U937 cells, a human leukemic monocyte lymphoma cell line, significantly decreased ERK1/2 phosphorylation after renin stimulation. Thus (P)RR expressed in human inflammatory cells might contribute to inflammation in ANCA-associated GN.

Elucidation of the etiology and characteristics of pink urine in young healthy subjects.

BACKGROUND: Pink urine syndrome (PUS) is attributed to the precipitation of uric acid caused by low urinary pH (U-pH). However, the reasons for the lower U-pH are unclear. OBJECTIVES: To investigate the occurrence of PUS and verified the cause of U-pH reduction. METHODS: Participants comprised 4,940 students who had undergone a physical examination. Data on the presence [PUS (+)] or absence [PUS (-)] of PUS, as well as age, gender, body mass index (BMI), blood pressure (BP), heart rate (HR), and U-pH were collected. Of these participants, 300 randomly selected individuals were evaluated for their waist circumference, as well as their levels of urinary C-peptide, angiotensinogen, methylglyoxal, thiobarbituric acid-reactive substances (TBARS), and Na(+) excretion. Independent risk factors of lower U-pH were decided by a multiple-regression analysis. RESULTS: PUS was observed in 216 students (4.4 %). A greater number of men comprised the PUS (+) group compared with the PUS (-) group, and subjects in this group had high BMI, BP, and HR values, as well as low U-pH. A logistic regression analysis revealed that the BMI and U-pH were independent risk factors for PUS (+). The decrease of U-pH was closely related to the progress of chronic kidney disease (CKD). BMI value was related to PUS (+) in the CKD (-) subjects. On the other hand, low U-pH was related to PUS (+) in the CKD (+) subjects. All factors other than HR showed a significant negative correlation with U-pH. However, multiple-regression analysis revealed that TBARS and angiotensinogen were independent risk factors. CONCLUSION: Obesity and lower U-pH were each independently related to PUS, whereas increased intrarenal oxidative stress and exacerbation of the renin-angiotensin system activation were associated with the lowering of U-pH. U-pH low value is related to potential CKD.

Association Between Home Blood Pressure and Body Composition by Bioimpedance Monitoring in Patients Undergoing Peritoneal Dialysis.

Home blood pressure (HBP) is an independent predictor of cardiovascular and renal function. However, no particular guidelines have been established for optimal HBP in peritoneal dialysis (PD) patients. Bioelectrical impedance analysis (BIA) is a beneficial tool for determining body composition. In the present study, we used BIA to determine body composition parameters that might play a role in the regulation of HBP in PD patients, and we compared HBP with office blood pressure (BP). Our study enrolled 15 patients (11 men, 4 women) receiving PD at Tohoku University Hospital, who, for 1 year, agreed to monitor HBP and to undergo body composition analysis. Patients were requested to measure HBP twice daily (morning, night) using a home BP device. A bioimpedance monitor was used to monitor body composition each month. Blood and urine samples were also analyzed each month. The relationships of average morning systolic HBP (sMHBP) with parameters of body composition and of blood and urine analyses were evaluated. The enrolledpatients were 66.3 ± 7.7 years of age and had a PD vintage of 28.3 ± 6.4 months. Overall, their sMHBP was 128 ± 13 mmHg and their office systolic BP was 126 ± 15 mmHg. Although office systolic BP and sMHBP both correlated with body fluid parameters [total body water (TBW)/height2], renal function (renal Kt/V serum creatinine), and heart function (left ventricular mass index), the correlation coefficient for sMHBP and TBW/height2 was highest, with sMHBP being the only independent predictor. Sodium intake was associated only with sMHBP. Our results suggest that body fluid status determined by BIA, heart and renal function, and sodium intake show better associations with sMHBP than with office systolic BP. Monitoring HBP and body composition by BIA are beneficial for the maintenance of volume status in PD patients.

Glucose and Insulin Response to Peritoneal Dialysis Fluid in Diabetic and Nondiabetic Peritoneal Dialysis Patients.

A postprandial increase in blood glucose in peritoneal dialysis (PD) patients with diabetes was observed in our previous study using continuous blood glucose monitoring. The response was observed in diabetic but not in nondiabetic PD patients. In addition, the response was reduced when patients used icodextrin; glucose absorbed from the peritoneum was responsible for the postprandial increase in blood glucose. Because our PD patients often change their PD fluid before meals, the present study aimed to determine the blood glucose and insulin responses to PD fluid. The 26 patients who agreed to participate in the study protocol [16 with diabetes (12 men, 4 women; 11 receiving insulin; 5 being controlled with oral antidiabetic drugs; average duration from diagnosis with diabetes: 16.4 ± 11 years); 10 without diabetes (4 men, 6 women)] had an average age of 60.5 ± 13.0 years. Average PD vintage was 578.7 ± 352.9 days. Blood samples were taken during a peritoneal equilibration test (PET) with 2.5% glucose solution at baseline and at 0.5, 2, and 4 hours. Levels of blood glucose and insulin were analyzed. A rapid increase in blood glucose (peak at 0.5 hours, 23.5 ± 22.2 mg/dL increase from baseline) was observed in nondiabetic patients. A delayed but higher peak response was observed in diabetic patients (peak at 1 hour, 54.9 ± 38.3 mg/dL increase from baseline). Peak response of insulin occurred at 0.5 hours in nondiabetic patients; in diabetic patients it occurred at 2 hours. No differences in the average insulin level during the PET were observed in the two groups (nondiabetic: 35.3 ± 15.6 µU/mL; diabetic: 38.9 ± 7.6 µU/mL). The study results suggest that a delayed insulin response after a PD fluid exchange could participate in the exaggerated postprandial increase in blood glucose in diabetic PD patients, particularly when the PD fluid exchange is performed before food intake.