Junichiro James Kazama

Clinical practice guideline for the management of chronic kidney disease-mineral and bone disorder

Masafumi Fukagawa, Keitaro Yokoyama, Fumihiko Koiwa, Masatomo Taniguchi, Tetsuo Shoji, Junichiro James Kazama, Hirotaka Komaba, Ryoichi Ando, Takatoshi Kakuta, Hideki Fujii, Msasaaki Nakayama, Yugo Shibagaki, Seiji Fukumoto, Naohiko Fujii, Motoshi Hattori, Akira Ashida, Kunitoshi Iseki, Takashi Shigematsu, Yusuke Tsukamoto, Yoshiharu Tsubakihara, Tadashi Tomo, Hideki Hirakata, and Tadao Akizawa for CKD-MBD Guideline Working Group, Japanese Society for Dialysis Therapy

Sevelamer hydrochloride and calcium bicarbonate reduce serum fibroblast growth factor 23 levels in dialysis patients.

Abstract:  Fibroblast growth factor 23 (FGF23) is a member of the fibroblast growth factor superfamily which displays a strong phosphaturic action and an inhibition of vitamin D 1‐α hydroxylase activity. Fourty‐six patients undergoing maintenance hemodialysis therapy participated in the study. They were randomly divided into 2 groups, and treated with either 3 g sevelamer hydrochloride + 3 g of calcium bicarbonate (CaCO3), or 3 g of CaCO3 alone. Serum FGF23 levels were determined by a sandwich enzyme‐linked immunosorbent assay (ELISA) system that detects the intact form of FGF23 molecules. Although the serum inorganic phosphate (Pi) levels were comparable before treatment, the levels were significantly lower in the patients treated with sevelamer hydrochloride + CaCO3 than those with CaCO3 alone after 4 weeks of treatment (P < 0.05). Serum FGF23 levels significantly decreased after 4 weeks of the treatment with sevelamer hydrochloride + CaCO3 from the pretreatment levels (P < 0.05), while no changes were found in the patients treated with CaCO3 alone. Thus, the use of sevelamer hydrochloride and CaCO3 reduced serum FGF23 levels in dialysis patients presumably through inhibiting phosphate load into the intestine.

An Overview of Regular Dialysis Treatment in Japan (As of 31 December 2010)

A nationwide statistical survey of 4226 dialysis facilities was conducted at the end of 2010, and 4166 facilities (98.6%) responded. The number of new patients introduced into dialysis was 37 512 in 2010. This number has decreased for two consecutive years since it peaked in 2008. The number of patients who died in 2010 was 28 882, which has been increasing every year. The number of patients undergoing dialysis at the end of 2010 was 298 252, which is an increase of 7591 (2.6%) compared with that at the end of 2009. The number of dialysis patients per million at the end of 2010 was 2329.1. The crude death rate of dialysis patients in 2010 was 9.8%, and has been gradually increasing. The mean age of the new patients introduced into dialysis was 67.8 years and the mean age of the entire dialysis patient population was 66.2 years. Regarding the primary disease of the new patients introduced into dialysis, the percentage of patients with diabetic nephropathy was 43.6%, which is a slight decrease from that in the previous year (44.5%). Patients with diabetic nephropathy as the primary disease accounted for 35.9% of the entire dialysis patient population, which approaches the percentage of patients with chronic glomerulonephritis as the primary disease (36.2%). The percentage of patients who had undergone carpal tunnel release surgery (CTx) was 4.3%, which is a slight decrease from that at the end of 1999 (5.5%). The decrease in the percentage of patients who had undergone CTx was significant among the patients with dialysis durations of 20–24 years (1999, 48.0%; 2010, 23.2%). A total weekly Kt/V attributable to peritoneal dialysis and their residual functional kidney was 1.7 or higher for 59.4% of patients who underwent peritoneal dialysis.

Short-term use of continuous positive airway pressure ameliorates glomerular hyperfiltration in patients with obstructive sleep apnoea syndrome.

Patients with OSAS (obstructive sleep apnoea syndrome) demonstrate renal signs such as proteinuria, glomerular hypertrophy and focal glomerular sclerosis. We performed a clinical study to investigate the glomerular function in OSAS patients and the short-term effect of CPAP (continuous positive airway pressure) on it. OSAS patients underwent a sodium thiosulphate and p-aminohippurate double clearance test, polysomnography and ambulatory blood pressure monitoring before and a week after the induction of CPAP. Twenty-seven consecutive patients (24 males) with moderate-to-severe OSAS admitted to our hospital for the induction of CPAP, and 32 healthy donors for renal transplantation as controls participated in the study. Before treatment, the glomerular filtration rate, estimated by the sodium thiosulphate clearance test, was within normal range, and the renal plasma flow was significantly lower than normal in the OSAS patients, thus the FF (filtration fraction) value was much higher than normal. FF before CPAP was not significantly correlated with age, body mass index or blood pressure; however, indices of increased hypoxaemia correlated with increased FF values. Polysomnographic variables after CPAP showed significant improvements in all patients, and only the nocturnal blood pressures were slightly lower than before CPAP. In 21 patients who underwent the clearance test after CPAP, FF significantly decreased from 0.26 +/- 0.04 to 0.23 +/- 0.03 (P < 0.001). OSAS patients were generally in a glomerular-hyperfiltrating condition that appeared to cause the renal findings associated with OSAS. CPAP might prevent nephropathy by ameliorating the glomerular hyperfiltration in OSAS patients.

Continuous Erythropoietin Delivery by Muscle-Targeted Gene Transfer Using in Vivo Electroporation

It has been demonstrated that gene transfer by in vivo electroporation of mouse muscle increases the level of gene expression by more than 100-fold over simple plasmid DNA injection. We tested continuous rat erythropoietin (Epo) delivery by this method in normal rats, using plasmid DNA expressing rat Epo (pCAGGS-Epo) as the vector. A pair of electrodes was inserted into the thigh muscles of rat hind limbs and 100 microg of pCAGGS-Epo was injected between the electrodes. Eight 100-V, 50-msec electric pulses were delivered through the electrodes. Each rat was injected with a total of 400 microg of pCAGGS-Epo, which was delivered to the medial and lateral sides of each thigh. The presence of vector-derived Epo mRNA at the DNA injection site was confirmed by RT-PCR. The serum Epo levels peaked at 122.2 +/- 33.0 mU/ml on day 7 and gradually decreased to 35.9 +/- 18.2 mU/ml on day 32. The hematocrit levels increased continuously, from the preinjection level of 49.5 +/- 1.1 to 67.8 +/- 2.2% on day 32 (p < 0.001). In pCAGGS-Epo treated rats, endogenous Epo secretion was downregulated on day 32. In a control experiment, intramuscular injection of pCAGGS-Epo without subsequent electroporation did not significantly enhance the serum Epo levels. These results demonstrate that muscle-targeted pCAGGS-Epo transfer by in vivo electroporation is a useful procedure for the continuous delivery of Epo.

Serum cystatin C reliably detects renal dysfunction in patients with various renal diseases.

A clinical investigation was conducted to clarify the reliability and efficacy of serum cystatin C measurement for estimation of the glomerular filtration rate (GFR). Two hundred twelve patients with various renal diseases enrolled in the study. All patients were evaluated for 24-hour creatinine clearance (24 h CCr) and the standard sodium thiosulfate clearance test (CThio) within a week of blood sample collection. Serum cystatin C concentration was determined by a particle-enhanced immunonephelometry method. CThio and 1/cystatin C, 24 h CCr, 1/β2-microglobulin and 1/creatinine were well correlated. The correlation coefficients for CThio obtained by 24 h CCr and 1/cystatin C were comparable to each other (0.701 vs. 0.679). Receiver-operated characteristic (ROC) analysis revealed that 24 h CCr showed the highest area under the curve when CThio = 60 ml/min or CThio = 100 ml/min were applied as the discrimination point. However, the ROC value obtained by cystatin C was slightly greater than 24 h CCr when CThio = 80 ml/min was used as the discrimination point. Patient age, gender, glucose tolerance, presence of proteinuria, systemic inflammation, lupus, or systemic use of steroids did not interfere in the relationship between CThio and 1/cystatin C. In conclusion, serum cystatin C measurement is an excellent diagnostic test for detecting patients with subclinical renal dysfunction.

An Overview of Regular Dialysis Treatment in Japan (as of 31 December 2012)

A nationwide statistical survey of 4279 dialysis facilities was conducted at the end of 2012, among which 4238 responded (99.0%). The number of new dialysis patients was 38 055 in 2012. Since 2008, the number of new dialysis patients has remained almost the same without any marked increase or decrease. The number of dialysis patients who died in 2012 was 30 710; a slight decrease from 2011 (30 743). The dialysis patient population has been growing every year in Japan; it was 310 007 at the end of 2012, which exceeded 310 000 for the first time. The number of dialysis patients per million at the end of 2012 was 2431.2. The crude death rate of dialysis patients in 2012 was 10.0%, a slight decrease from that in 2011 (10.2%). The mean age of new dialysis patients was 68.5 years and the mean age of the entire dialysis patient population was 66.9 years. The most common primary cause of renal failure among new dialysis patients was diabetic nephropathy (44.2%). The actual number of new dialysis patients with diabetic nephropathy has been approximately 16 000 for the last few years. Diabetic nephropathy was also the most common primary disease among the entire dialysis patient population (37.1%), followed by chronic glomerulonephritis (33.6%). The percentage of dialysis patients with diabetic nephropathy has been continuously increasing, whereas not only the percentage but also the actual number of dialysis patients with chronic glomerulonephritis has decreased. The number of patients who underwent hemodiafiltration (HDF) at the end of 2012 was 21 725, a marked increase from that in 2011 (14 115). In particular, the number of patients who underwent on‐line HDF increased threefold from 4890 in 2011 to 14 069 in 2012. From the results of the facility survey, the number of patients who underwent peritoneal dialysis (PD) was 9514 and that of patients who did not undergo PD despite having a PD catheter in the abdominal cavity was 347. From the results of the patient survey, among the PD patients, 1932 also underwent another dialysis method using extracorporeal circulation, such as hemodialysis (HD) and HDF. The number of patients who underwent HD at home in 2012 was 393, a marked increase from that in 2011 (327).

Overview of Regular Dialysis Treatment in Japan (as of 31 December 2011)

A nationwide statistical survey of 4255 dialysis facilities was conducted at the end of 2011. Responses were submitted by 4213 facilities (99.0%). The number of new patients started on dialysis was 38 613 in 2011. Although the number of new patients decreased in 2009 and 2010, it increased in 2011. The number of patients who died each year has been increasing; it was 30 743 in 2011, which exceeded 30 000 for the first time. The number of patients undergoing dialysis has also been increasing every year; it was 304 856 at the end of 2011, which exceeded 300 000 for the first time. The number of dialysis patients per million at the end of 2011 was 2385.4. The crude death rate of dialysis patients in 2011 was 10.2%, which exceeded 10% for the first time in the last 20 years. The mean age of new dialysis patients was 67.84 years and the mean age of the entire dialysis patient population was 66.55 years. The most common primary cause of renal failure among new dialysis patients was diabetic nephropathy (44.3%). Diabetic nephropathy was also the most common primary disease among the entire dialysis patient population (36.7%), exceeding chronic glomerulonephritis (34.8%) which had been the highest until last year. The survey included questions related to the Great East Japan Earthquake, which occurred on 11 March 2011. The results on items associated with the Great East Japan Earthquake were reported separately from this report. The mean uric acid levels of the male and female patients were 7.30 and 7.19 mg/dL, respectively. Certain drugs for hyperuricemia were prescribed for approximately 17% of patients. From the results of the facility survey, the number of patients who underwent peritoneal dialysis (PD) was 9642 and the number of patients who did not undergo PD despite having a peritoneal dialysis catheter was 369. A basic summary of the results on the survey items associated with PD is included in this report and the details were reported separately.

Evidence for megalin-mediated proximal tubular uptake of L-FABP, a carrier of potentially nephrotoxic molecules.

Liver-type fatty acid binding protein (L-FABP) binds with high affinity to hydrophobic molecules including free fatty acid, bile acid and bilirubin, which are potentially nephrotoxic, and is involved in their metabolism mainly in hepatocytes. L-FABP is released into the circulation, and patients with liver damage have an elevated plasma L-FABP level. L-FABP is also present in renal tubules; however, the precise localization of L-FABP and its potential role in the renal tubules are not known. In this study, we examined the cellular and subcellular localization of L-FABP in the rat kidney and tried to determine from where the L-FABP in kidney tissues had originated. Immunohistochemical studies of kidney sections localized L-FABP in the lysosomes of proximal tubule cells (PTC). In rats with carbon tetrachloride (CCl4)-induced acute liver injury, we detected high levels of L-FABP in the circulation and in the kidney compared with those in the control rat by immunoblotting, while reverse transcription-polymerase chain reaction showed that the level of L-FABP mRNA expression in the kidney of CCl4-treated rats was low and did not differ from that in the control rat. When 35S-L-FABP was intravenously administered to rats, the kidneys took up 35S-L-FABP more preferentially than the liver and heart, and histoautoradiography of kidney sections revealed that 35S-L-FABP was internalized via the apical domains of PTC. Quartz-crystal microbalance analysis revealed that L-FABP bound to megalin, a multiligand endocytotic receptor on PTC, in a Ca2+-dependent manner. Degradation assays using megalin-expressing rat yolk sac tumor-derived L2 cells demonstrated that megalin mediated the cellular uptake and catabolism of 125I-L-FABP. In conclusion, circulatory L-FABP was found to be filtered by glomeruli and internalized by PTC probably via megalin-mediated endocytosis. These results suggest a novel renal uptake pathway for L-FABP, a carrier of hydrophobic molecules, some of which may exert nephrotoxic effects.

Overview of Regular Dialysis Treatment in Japan (as of 31 December 2009)

A nationwide statistical survey of 4196 dialysis facilities was conducted at the end of 2009, and 4133 facilities (98.5%) responded. The number of patients undergoing dialysis at the end of 2009 was determined to be 290 661, an increase of 7240 patients (2.6%) compared with that of 2008. The number of dialysis patients per million at the end of 2009 was 2279.5. The crude death rate of dialysis patients from the end of 2008 to the end of 2009 was 9.6%. The mean age of the new patients introduced into dialysis was 67.3 years old and the mean age of the entire dialysis patient population was 65.8 years old. Primary diseases such as diabetic nephropathy and chronic glomerulonephritis for new dialysis patients, showed a percentage of 44.5% and 21.9%, respectively. Based on the facilities surveyed, 84.2% of the facilities that responded to the questionnaire satisfied the microbiological quality standard for dialysis fluids for the Japanese Society for Dialysis Therapy (JSDT), with an endotoxin concentration of less than 0.05 EU/mL in the dialysis fluid. Similarly, 98.2% of the facilities surveyed satisfied another standard of the society of a bacterial count of less than 100 cfu/mL in the dialysis fluid. The facility survey indicated that the number of patients who were treated by blood purification by both peritoneal dialysis and extracorporeal circulation, such as hemodialysis, was 1720. Among the total number of patients, 24.8% were satisfied with the management target recommended in the treatment guidelines for secondary hyperparathyroidism. These standards are set by the JSDT, based on the three parameters, i.e. serum calcium concentration, serum phosphorus concentration, and serum intact parathyroid hormone concentration. According to the questionnaire, 9.8% of the patients were considered to have a complication of dementia.