The impact of a remote monitoring system of healthcare resource consumption in patients on automated peritoneal dialysis (APD): A simulation study
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AIMS: Remote monitoring (RM) can improve management of chronic diseases. We evaluated the impact of RM in automated peritoneal dialysis (APD) in a simulation study. MATERIALS AND METHODS: We simulated 12 patient scenarios with common clinical problems and estimated the likely healthcare resource consumption with and without the availability of RM (RM+ and RM- groups, respectively). Scenarios were evaluated 4 times by randomly allocated nephrologist-nurse teams or nephrologist-alone assessors. RESULTS: The RM+ group was assessed as having significantly lower total healthcare resource consumption compared with the RM- group (36.8 vs. 107.5 total episodes of resource consumption, p = 0.002). The RM+ group showed significantly lower "unplanned hospital visits" (2.3 vs. 11.3, p = 0.005), "emergency room visits" (0.5 vs. 5.3, p = 0.003), "home visits" (0.5 vs. 5.8, p = 0.016), "exchanges over the telephone" (18.5 vs. 57.8, p = 0.002), and "change to hemodialysis" (0.5 vs. 2.5, p = 0.003). Evaluations did not differ between nephrologist-nurse teams vs. nephrologist-alone assessors. CONCLUSION: RM can be expected to reduce healthcare resource consumption in APD patients.
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The role of adipose tissue asymmetric dimethylarginine/dimethylarginine dimethylaminohydrolase pathway in adipose tissue phenotype and metabolic abnormalities in subtotally nephrectomized rats.

BACKGROUND: The lipodystrophy-like phenotype has been suggested in early chronic kidney disease (CKD). It includes adipose tissue atrophy, systemic insulin resistance (IR), dyslipidemia and ectopic lipid accumulation. To elucidate its pathogenesis, we investigated the role of two uremic toxins that affect insulin sensitivity: an endogenous nitric oxide synthase inhibitor, and asymmetric dimethylarginine (ADMA) and indoxyl sulfate (IS). METHODS: Six-week-old Sprague-Dawley rats were rendered CKD by subtotal nephrectomy (Nx) and compared with sham-operated rats. Cultured 3T3-L1 fibroblasts were differentiated into mature adipocytes with or without ADMA. Transgenic (Tg) mice overexpressing each isoform of ADMA degrading enzyme, dimethylarginine dimethylaminohydrolase 1 (DDAH1) and DDAH2 were subject to Nx and their phenotypes were investigated. RESULTS: In Nx rats, IR was evident and insulin stimulation failed to activate insulin signaling in adipose tissues. Adipose tissue weight, adipocyte size and adipocyte differentiation marker expressions decreased as a consequence of IR in Nx. Tissue lipid content in the liver and muscle increased in Nx rats. Tissue levels of ADMA, IS and oxidative stress increased in the adipose tissue of Nx rats. Both DDAH1 and DDAH2 expressions decreased, and a putative IS receptor, aryl hydrocarbon receptor, expression increased in the adipose tissue of Nx rats. ADMA inhibited adipocyte differentiation, triglyceride accumulation and insulin signaling, which were reversed by pretreatment with cGMP. In each type of Tg mice overexpressing DDAH1 or DDAH2, all lipodystrophy-like phenotypes induced by Nx were reversed. CONCLUSIONS: In mild CKD, dysregulation of the ADMA/DDAH pathway in adipose tissue triggers lipodystrophy-like phenotype changes, including ectopic fat depositions.

Insulin resistance in chronic kidney disease is ameliorated by spironolactone in rats and humans.

In this study, we examined the association between chronic kidney disease (CKD) and insulin resistance. In a patient cohort with nondiabetic stages 2-5 CKD, estimated glomerular filtration rate (eGFR) was negatively correlated and the plasma aldosterone concentration was independently associated with the homeostasis model assessment of insulin resistance. Treatment with the mineralocorticoid receptor blocker spironolactone ameliorated insulin resistance in patients, and impaired glucose tolerance was partially reversed in fifth/sixth nephrectomized rats. In these rats, insulin-induced signal transduction was attenuated, especially in the adipose tissue. In the adipose tissue of nephrectomized rats, nuclear mineralocorticoid receptor expression, expression of the mineralocorticoid receptor target molecule SGK-1, tissue aldosterone content, and expression of the aldosterone-producing enzyme CYP11B2 increased. Mineralocorticoid receptor activation in the adipose tissue was reversed by spironolactone. In the adipose tissue of nephrectomized rats, asymmetric dimethylarginine (ADMA; an uremic substance linking uremia and insulin resistance) increased, the expression of the ADMA-degrading enzymes DDAH1 and DDAH2 decreased, and the oxidative stress increased. All of these changes were reversed by spironolactone. In mature adipocytes, aldosterone downregulated both DDAH1 and DDAH2 expression, and ADMA inhibited the insulin-induced cellular signaling. Thus, activation of mineralocorticoid receptor and resultant ADMA accumulation in adipose tissue has, in part, a relevant role in the development of insulin resistance in CKD.

Impact of Peritoneal Dialysis Catheter Insertion by a Nephrologist: Results of a Questionnaire Survey of Patients and Nurses.

Peritoneal dialysis (PD) is an excellent dialysis mo- dality, but it is underutilized in the United States and Japan. In the present study, we evaluated the impact of interventional nephrology in PD on the impres- sions held by patients and nurses about selection of a renal replacement therapy and the complications associated with PD therapy. Over aperiod of 7 years, PD catheter insertion in 120 patients with end-stage renal disease (age: 63.0 ± 13.3 years) was performed by nephrologists at Keio University Hospital or Saitama Medical Center. A questionnaire survey evaluating the advantages and disadvantages of this interventional nephrology approach in PD was distributed to 72 PD patients and to 53 nurses in charge of those patients. After interventional nephrology in PD was adopted, the number of patients selecting PD therapy increased. The incidence of peritonitis was relatively low (1 episode in 101.1 patient-months). Responses to the questionnaire survey showed that neither patients nor nurses were concerned about catheter insertion by physicians, and no communication problems between the patients, nurses, and physicians were reported. Approximately 60% of the nurses specializing in PD therapy showed higher motivation with interventional nephrology, which might have a favorable effect on the selection of PD therapy, on the incidence of peritonitis, and on the tripartite communication between patients, nurses, and physicians.

A Case Report of Autosomal Dominant Polycystic Kidney Disease Under Peritoneal Dialysis With Cyst Infection and Culture-Positive Peritoneal Fluid.

BACKGROUND: Cyst infection is a complication sometimes seen in patients with autosomal dominant polycystic kidney disease (ADPKD) and often shows through a positive blood culture. However, there have been no reports of ADPKD patients whose cyst infection propagate to peritoneal fluid leading to positive peritoneal fluid culture. CASE PRESENTATION: A 74-year-old Japanese man with ADPKD under peritoneal dialysis (PD) was presented with left flank pain, fever, and chills at our hospital. He did not show any symptoms or signs suggestive of peritonitis. There were no elevated cell counts or polymorphonuclear leucocytes in his PD fluid. There were some complicated cysts found in computed tomography and magnetic resonance imaging examinations. We clinically diagnosed him as having a renal cyst infection rather than PD-related peritonitis. We initiated treatment by administering ceftriaxone with an immediate favorable response. As the possibility of accompanying prostatitis still remained, we switched to intravenous levofloxacin on the second day. On the 10th day, Helicobacter cinaedi was detected in 2 sets of blood culture as well as in PD fluid. We switched back to ceftriaxone and this treatment was entirely successful. CONCLUSIONS: This is the first report of H cinaedi cyst infection which propagates to peritoneal fluid in a patient with ADPKD.

Non-Tuberculous Mycobacterial Infections Related to Peritoneal Dialysis.

Most infections related to peritoneal dialysis (PD) are caused by common bacteria, and non-tuberculous mycobacteria are rare. The clinical characteristics and prognosis of PD patients with non-tuberculous mycobacterial infections were investigated at our hospital. Non-tuberculous mycobacteria were detected in 11 patients (exit-site infection, tunnel infection, and peritonitis in 3, 5, and 3 patients, respectively). Mycobacterium fortuitum, Mycobacterium chelonae, and Mycobacterium abscessus were identified in 4, 2, and 2 patients, respectively. Most patients with peritonitis or tunnel infection required catheter removal. During the study period (2007 - 2017), peritonitis occurred in 44 patients, including 3 patients (6.8%) with non-tuberculous mycobacterial peritonitis. When non-tuberculous mycobacterial infection occurs, multi-agent antibiotic therapy, unroofing surgery, and/or catheter replacement should be performed to prevent peritonitis.

Penile calciphylaxis in a patient on combined peritoneal dialysis and hemodialysis.

Calciphylaxis presents with painful purpura and intractable skin ulcers on the trunk and particularly the distal extremities, and it mainly occurs in patients on chronic dialysis. A 66-year-old man with renal failure due to diabetic nephropathy was on peritoneal dialysis alone for 1 year, followed by peritoneal dialysis combined with hemodialysis for 3 years. He developed calciphylaxis of the penis, which was diagnosed from the skin biopsy findings and clinical observation. To treat this condition, PD was stopped and HD was performed three times a week. In addition, warfarin therapy was discontinued and infusion of sodium thiosulfate was performed. The penile ulcers decreased in size and pain was markedly improved, so the patient was discharged from hospital. Following discharge, PD was resumed after changing the peritoneal dialysis fluid to bicarbonate-buffered dialysate. The penile ulcers eventually resolved completely. There have been very few reports about calciphylaxis in patients on combined dialysis modalities. In our patient, penile calciphylaxis progressed when lactate-buffered peritoneal dialysis fluid was used and resolved after switching to bicarbonate-buffered fluid together with cessation of warfarin therapy and infusion of sodium thiosulfate.

Communication from Tubular Epithelial Cells to Podocytes through Sirt1 and Nicotinic Acid Metabolism.

We have recently published that tubular epithelial cells affect the podocyte epigenome though nicotinic acid metabolism in diabetic nephropathy (DN), and we have named this relationship "proximal tubule-podocyte communication". In this review, we describe this novel mechanism in the early stage of DN, focusing on the function of renal tubular Sirt1 and Sirt1-related nicotinic acid metabolism. Mainly, we discuss the following three findings. First, we described the details of proximal tubule-podocyte communication. Second, we explained how Sirt1 regulates albuminuria via epigenetic mechanisms. This means that repeated high glucose stress triggers the initial changes in proximal tubules, which lead to the epigenetically irreversible glomerular damages. However, proximal tubular Sirt1 overexpression can rescue these changes. Our previous data indicated that the decrease in Sirt1 expression in proximal tubules caused the reduction in glomerular Sirt1 and the subsequent increase in glomerular Claudin-1. It seemed plausible that some humoral mediator is released from proximal tubules, migrates to podocytes and glomeruli, and affects Sirt1 expression in podocytes. Third, we mentioned a mediator connecting this communication, nicotinamide mononucleotide (NMN). We suggest the potential of Sirt1 or NMN as not only a therapeutic target but also as a prognostic marker of very early stage DN.

Impact of Switching From Darbepoetin Alfa to Epoetin Beta Pegol on Iron Utilization and Blood Pressure in Peritoneal Dialysis Patients.

New erythropoiesis-stimulating agents with a longer half-life have been developed for the treatment of anemia in patients with end-stage renal disease. This study evaluated the efficacy of darbepoetin alfa (DA) and long-acting epoetin beta pegol (continuous erythropoietin receptor activator, CERA) in patients on peritoneal dialysis (PD). Twenty-nine patients who had undergone PD for at least 6 months and were iron replacement-naïve and negative for inflammatory parameters were enrolled. Hemoglobin (Hgb) levels and blood pressure were evaluated before and after switching from DA to CERA. Percent transferrin saturation (TSAT), serum ferritin levels and blood pressure were also assessed. Twenty-eight patients were subject to the analysis, excluding one patient with a decrease in Hgb by ≥10%. Switching from DA to CERA did not alter Hgb levels. The doses of DA and CERA after 12 month treatment of each agent were 118.48 ± 79.63 and 89.88 ± 47.50 µg/4 weeks, respectively (conversion ratio, 1:0.76). The CERA dose administered during the final 6 months was abated, compared with that given during the initial 6 months (P = 0.035). The frequency of CERA injection over a 12-month period was less than that of DA (10.0 ± 3.0 vs. 16.4 ± 5.0, P < 0.01). The conversion from DA to CERA did not alter TSAT, but decreased serum ferritin levels (from 202.69 ± 132.57 to 150.15 ± 110.07 ng/mL, P = 0.012) and systolic blood pressure (from 133.8 ± 17.3 to 129.5 ± 11.3 mm Hg, P = 0.024). In PD patients, lower doses and less frequent injection of CERA are sufficient to maintain Hgb at levels similar to those achieved by DA therapy, with improved iron utilization and reduced blood pressure.

Ghrelin protects against renal damages induced by angiotensin-II via an antioxidative stress mechanism in mice.

We explored the renal protective effects by a gut peptide, Ghrelin. Daily peritoneal injection with Ghrelin ameliorated renal damages in continuously angiotensin II (AngII)-infused C57BL/6 mice as assessed by urinary excretion of protein and renal tubular markers. AngII-induced increase in reactive oxygen species (ROS) levels and senescent changes were attenuated by Ghrelin. Ghrelin also inhibited AngII-induced upregulations of transforming growth factor-ß (TGF-ß) and plasminogen activator inhibitor-1 (PAI-1), ameliorating renal fibrotic changes. These effects were accompanied by concomitant increase in mitochondria uncoupling protein, UCP2 as well as in a key regulator of mitochondria biosynthesis, PGC1α. In renal proximal cell line, HK-2 cells, Ghrelin reduced mitochondria membrane potential and mitochondria-derived ROS. The transfection of UCP2 siRNA abolished the decrease in mitochondria-derived ROS by Ghrelin. Ghrelin ameliorated AngII-induced renal tubular cell senescent changes and AngII-induced TGF-ß and PAI-1 expressions. Finally, Ghrelin receptor, growth hormone secretagogue receptor (GHSR)-null mice exhibited an increase in tubular damages, renal ROS levels, renal senescent changes and fibrosis complicated with renal dysfunction. GHSR-null mice harbored elongated mitochondria in the proximal tubules. In conclusion, Ghrelin suppressed AngII-induced renal damages through its UCP2 dependent anti-oxidative stress effect and mitochondria maintenance. Ghrelin/GHSR pathway played an important role in the maintenance of ROS levels in the kidney.