Association between Serum 25-Hydroxyvitamin D Levels and Sarcopenia in Patients Undergoing Chronic Haemodialysis.

INTRODUCTION: Sarcopenia and vitamin D deficiency are highly prevalent among patients undergoing haemodialysis. Although vitamin D deficiency, assessed using serum 25-hydroxyvitamin D (25(OH)D) levels, is known to be associated with sarcopenia in the general population, whether serum 25(OH)D levels are associated with sarcopenia in patients undergoing haemodialysis with suppressed renal activation of 25(OH)D remains unclear. This study aimed to examine the association between serum 25(OH)D levels and sarcopenia in patients undergoing haemodialysis. METHODS: Serum 25(OH)D level measurements and assessment of sarcopenia using the Asian Working Group for Sarcopenia criteria were conducted in 95 stable outpatients undergoing maintenance haemodialysis therapy. RESULTS: Sarcopenia was observed in 22 (23.1%) patients. In multiple logistic regression analysis, serum 25(OH)D levels were associated with sarcopenia (odds ratio [OR] 0.87, 95% confidence interval [CI] 0.77-0.99, p = 0.039) independent of traditional risk factors for sarcopenia. In multiple linear regression analyses, serum 25(OH)D levels were associated with parameters of skeletal muscle mass and strength (ß = 0.145, p = 0.046, and ß = 0.194, p = 0.020, respectively). The adjusted OR for sarcopenia was 5.60 (95% CI 1.52-20.57, p = 0.009) in the vitamin D deficiency group categorized based on the cut-off serum 25(OH)D level of 10 ng/mL. Regarding model discrimination, adding vitamin D deficiency to the traditional risk factors significantly improved the integrated discrimination improvement score (0.093, p = 0.007). CONCLUSION: Lower serum 25(OH)D levels were associated with sarcopenia independent of traditional risk factors in patients undergoing haemodialysis with suppressed vitamin D activation in the kidney. This finding implies that circulating 25(OH)D may have an important relationship with the skeletal muscle function of patients undergoing haemodialysis, and its measurement may be recommended to identify patients at high risk for sarcopenia among those undergoing haemodialysis.

Coexistence of Low Muscle Mass and Osteoporosis as a Predictor of Fragility Fractures in Long-Term Kidney Transplant Recipients.

INTRODUCTION: Sarcopenia and osteoporosis are highly prevalent among kidney transplant recipients (KTRs). Although osteoporosis is known to increase fracture risk in KTRs, it is unclear whether sarcopenia or osteosarcopenia is associated with this increased risk. Thus, we aimed to investigate the association of the coexistence of low muscle mass (LMM) and osteoporosis with the risk of fracture in long-term KTRs. METHODS: Exactly 342 stable KTRs underwent dual-energy X-ray absorptiometry and skeletal muscle mass index (SMI) measurement using bioelectrical impedance analysis. RESULTS: LMM and osteoporosis were observed in 109 (31.9%) and 93 patients (27.2%), respectively. During a follow-up period of 5.1 years, 48 (14.0%) fractures occurred. KTRs with LMM had a higher fracture risk, but this was not significant (adjusted hazard ratio [aHR] 1.82, 95% confidence interval [CI] 0.94-3.50, p = 0.073). Similar results were obtained in KTRs with osteoporosis (aHR 1.84, 95% CI 0.96-3.47, p = 0.063). We divided the KTRs into four groups according to the presence of LMM and/or osteoporosis. The cumulative incidence rates of fractures were 13.0%, 11.1%, 10.5%, and 31.3% in the KTRs without both LMM and osteoporosis, those with LMM alone, those with osteoporosis alone, and those with both, respectively. The KTRs with both LMM and osteoporosis had a 2.92fold higher risk of fractures (95% CI 1.29-6.49; p = 0.010) than those without both LMM and osteoporosis. CONCLUSION: Long-term KTRs with the coexistence of LMM and osteoporosis had an independently higher risk of fragility fractures than those without both LMM and osteoporosis. The combination of SMI and osteoporosis definitions can be used to identify KTRs with a high fracture risk.

Lateral spine dual-energy X-ray absorptiometry and the risk of fragility fractures in long-term kidney graft recipients.

BACKGROUND: Although the prevalence of osteoporosis and fractures in the first 6-12 months post-renal transplantation is high, little is known about the utility of bone mineral density (BMD) to predict fractures in long-term kidney graft recipients. Lateral spine dual-energy X-ray absorptiometry (DXA) scanning is a reliable tool for measuring glucocorticoid-induced and age-related bone loss in the elderly population. However, little is known about the utility of lateral spine DXA for patients with chronic kidney diseases. This study aimed to analyze the utility of lateral spine BMD for fragility fractures in long-term kidney graft recipients. METHODS: A total of 357 stable kidney transplant recipients for a minimum of 1 year after kidney transplantation underwent DXA measurements at several sites, including the lateral spine between January 2017 and December 2018. We collected data on new incident fractures from the patients' medical records. RESULTS: The median post-transplantation time at baseline DXA measurement was 12.6 years. During the median follow-up period of 3.5 years, 41 (11.4%) fractures occurred. The lateral spine BMDs were independently associated with fractures (adjusted hazard ratio 0.076; 95% confidence interval 0.012-0.42, p = 0.003). The cumulative incidence rate of fractures was significantly higher in the lower lateral spine BMD group (< 0.471 g/cm2, optimal cut-off value by receiver operating characteristic curve) than in the higher lateral spine BMD group (23.4 vs. 7.4%, adjusted hazard ratio 4.92; 95% confidence interval 2.33-10.74, p < 0.001). CONCLUSION: Lateral lumbar spine BMD can be used to predict the risk of fragility fractures in long-term kidney graft recipients.

The importance of kidney volume as a marker in the assessment of living-donor kidney transplantation in Japan.

BACKGROUND: In living kidney transplantation, predicting the risk of end-stage kidney disease in the organ donors though crucial remains to be resolved. Thus, any useful biomarker to predict kidney outcome would be highly desirable to safeguard donors. METHODS: This retrospective study was conducted at Nagoya Daini Red Cross Hospital to confirm whether an increase in preserved kidney volume (PKV) was a predict marker of proteinuria. A change of PKV before and 1 year after kidney donation was measured, and its association with proteinuria 3 years after the donation was analyzed. RESULTS: A total of 119 kidney donors who met the Japanese donor guideline were enrolled. The mean age was 57.4 years, 46.2% were male. The mean values of the variables before kidney donation (baseline) were: BMI levels: 23.4 kg/m2, BSA-adjusted PKV: 132.9 cm3/1.73 m2, and estimated glomerular filtration rate (eGFRave): 82.9 mL/min/1.73 m2. A positive correlation was noted between BSA-adjusted PKV and eGFRave (r = 0.61, p < 0.001). BSA-adjusted PKV increased by 19.5% 1 year after donation, and the median urine protein was 0.04 g/gCre. Linear regression analyses showed that change of PKV and BSA-adjusted PKV before the donation were significantly associated with proteinuria 3 years after donation. CONCLUSION: Change of PKV and BSA-adjusted PKV before donation is important factors for proteinuria after donation under the Japanese donor guidelines. Further studies are needed to confirm whether these factors are associated with renal survival after donation.

Two-year retrospective study of the effect of preemptive kidney transplantation and pretransplant mineral bone factors on calcium in post-kidney transplant recipients.

BACKGROUND: Preemptive kidney transplantation (PEKT) incidence has recently increased in Japan. The effect of PEKT and mineral bone factors before kidney transplantation (KTx) on long-term calcium (Ca) levels remains unknown. METHODS: Eighty-one consecutive patients at Nagoya Daini Red Cross Hospital were included in this study (PEKT group with 41 patients and non PEKT group with 40 patients). Ca metabolism, including intact fibroblast growth factor 23 (iFGF23), were measured before KTx and intact parathyroid hormone (iPTH), and corrected Ca (cCa) were measured before KTx and 6 months (M), 12 M, and 24 M after KTx. RESULTS: In PEKT group, cCa levels at 24 M were higher from the baseline level. At baseline, cCa levels had a positive correlation with iFGF23 levels (r = 0.51; p < 0.001) and a negative correlation with iPTH levels (r = 0.51; p < 0.001). The cCa difference between baseline and 24 M was 0.8 ± 0.6 mg/dL in PEKT group and 0.3 ± 0.7 mg/dL in non-PEKT group (p = 0.001). A multivariate linear regression analysis showed iFGF23 and iPTH at baseline in entire groups were useful markers on calcium levels at 24 M. However, in PEKT group, both markers were found to be not associated with Ca at 24 M, whereas in non PEKT group, iPTH was the only effective marker. CONCLUSIONS: This study suggested that iFGF23 and iPTH may be useful markers of the calcium status after KTx. However, no correlation was noted in PEKT group.

Incidence of remission and relapse of proteinuria, end-stage kidney disease, mortality, and major outcomes in primary nephrotic syndrome: the Japan Nephrotic Syndrome Cohort Study (JNSCS).

BACKGROUND: Despite recent advances in immunosuppressive therapy for patients with primary nephrotic syndrome, its effectiveness and safety have not been fully studied in recent nationwide real-world clinical data in Japan. METHODS: A 5-year cohort study, the Japan Nephrotic Syndrome Cohort Study, enrolled 374 patients with primary nephrotic syndrome in 55 hospitals in Japan, including 155, 148, 38, and 33 patients with minimal change disease (MCD), membranous nephropathy (MN), focal segmental glomerulosclerosis (FSGS), and other glomerulonephritides, respectively. The incidence rates of remission and relapse of proteinuria, 50% and 100% increases in serum creatinine, end-stage kidney disease (ESKD), all-cause mortality, and other major adverse outcomes were compared among glomerulonephritides using the Log-rank test. Incidence of hospitalization for infection, the most common cause of mortality, was compared using a multivariable-adjusted Cox proportional hazard model. RESULTS: Immunosuppressive therapy was administered in 339 (90.6%) patients. The cumulative probabilities of complete remission within 3 years of the baseline visit was ≥ 0.75 in patients with MCD, MN, and FSGS (0.95, 0.77, and 0.79, respectively). Diabetes was the most common adverse events associated with immunosuppressive therapy (incidence rate, 71.0 per 1000 person-years). All-cause mortality (15.6 per 1000 person-years), mainly infection-related mortality (47.8%), was more common than ESKD (8.9 per 1000 person-years), especially in patients with MCD and MN. MCD was significantly associated with hospitalization for infection than MN. CONCLUSIONS: Patients with MCD and MN had a higher mortality, especially infection-related mortality, than ESKD. Nephrologists should pay more attention to infections in patients with primary nephrotic syndrome.

Better remission rates in elderly Japanese patients with primary membranous nephropathy in nationwide real-world practice: The Japan Nephrotic Syndrome Cohort Study (JNSCS).

BACKGROUND: The aim of the present study was to clarify the prevalence of immunosuppressive drug use and outcomes in elderly and non-elderly patients with primary membranous nephropathy (MN) in nationwide real-world practice in Japan. PATIENTS AND METHODS: Between 2009 and 2010, 374 patients with primary nephrotic syndrome were enrolled in the cohort study (The Japan Nephrotic Syndrome Cohort Study, JNSCS), including 126 adult patients with MN. Their clinical characteristics were compared with those of nephrotic patients with primary MN registered in a large nationwide registry (The Japan Renal Biopsy Registry, J-RBR). Outcomes and predictors in the elderly (≥ 65 years) and non-elderly groups were identified. RESULTS: Similar clinical characteristics were observed in JNSCS patients and J-RBR patients (n = 1808). At the early stage of 1 month, 84.1% of patients were treated with immunosuppressive therapies. No significant differences were observed in therapies between age groups. However, elderly patients achieved complete remission (CR) more frequently than non-elderly patients, particularly those treated with therapies that included corticosteroids. No significant differences were noted in serum creatinine (sCr) elevations at 50 or 100%, end-stage kidney disease, or all-cause mortality between age groups. Corticosteroids were identified as an independent predictor of CR (HR 2.749, 95%CI 1.593-4.745, p = 0.000) in the multivariate Cox's model. sCr levels, hemoglobin levels, immunosuppressants, clinical remission, and relapse after CR were independent predictors of sCr × 1.5 or × 2.0. CONCLUSION: Early immunosuppressive therapy including corticosteroids for primary MN showed better remission rates in elderly patients in a nationwide cohort study.

The effect of maintaining high hemoglobin levels on long-term kidney function in kidney transplant recipients: a randomized controlled trial.

BACKGROUND: Posttransplant anemia may be a major determinant of chronic allograft nephropathy. However, the impact of correcting anemia on graft function remains controversial. METHODS: A 3-year follow-up of an open-label, multicenter, randomized controlled trial involving kidney transplantation recipients examined whether sustained maintenance of target hemoglobin (Hb) concentrations at a high level (12.5-13.5 g/dL, n = 64) with either darbepoetin alfa or epoetin beta pegol would slow the graft function decline rate as the primary efficacy endpoint, compared with maintenance of a low Hb concentration (10.5-11.5 g/dL, n = 63). RESULTS: The mean blood pressures in the two groups were well controlled throughout the study. In the high Hb group, mean Hb concentrations increased to >12 g/dL at 3 months, reaching the target range at 18 months. At the end of this study (36 months), the mean Hb concentration was 12.8 ± 0.7 g/dL in the high Hb group and 11.5 ± 1.2 g/dL in the low Hb group. The decline rate of the estimated glomerular filtration (eGFR) rate was considerably greater in the low Hb group (ΔeGFR, -5.1 ± 9.5 mL/min/1.73 m2) than in the high Hb group (-1.0 ± 8.4 mL/min/1.73 m2) (P = 0.02). Of note, only a few high Hb patients developed cardiovascular events and returned to hemodialysis, but the low Hb patients did not. CONCLUSION: This prospective study suggests that correcting anemia to the target Hb level range (12.5-13.5 g/dL) slows renal function deterioration by >3 years in the chronic phase of allograft nephropathy.

Regional variations in immunosuppressive therapy in patients with primary nephrotic syndrome: the Japan nephrotic syndrome cohort study.

BACKGROUND: The lack of high-quality clinical evidences hindered broad consensus on optimal therapies for primary nephrotic syndromes. The aim of the present study was to compare prevalence of immunosuppressive drug use in patients with primary nephrotic syndrome across 6 regions in Japan. METHODS: Between 2009 and 2010, 380 patients with primary nephrotic syndrome in 56 hospitals were enrolled in a prospective cohort study [Japan Nephrotic Syndrome Cohort Study (JNSCS)], including 141, 151, and 38 adult patients with minimal change disease (MCD), membranous nephropathy (MN), and focal segmental glomerulosclerosis (FSGS), respectively. Their clinical characteristics were compared with those of patients registered in a large nationwide registry of kidney biopsies [Japan Renal Biopsy Registry (J-RBR)]. The regional prevalence of use of each immunosuppressive drug was assessed among adult MCD, MN, and FSGS patients who underwent immunosuppressive therapy in the JNSCS (n = 139, 127, and 34, respectively). Predictors of its use were identified using multivariable-adjusted logistic regression models. RESULTS: The clinical characteristics of JNSCS patients were comparable to those of J-RBR patients, suggesting that the JNSCS included the representatives in the J-RBR. The secondary major immunosuppressive drugs were intravenous methylprednisolone [n = 33 (24.6%), 24 (19.7%), and 9 (28.1%) in MCD, MN, and FSGS, respectively] and cyclosporine [n = 25 (18.7%), 62 (50.8%), and 16 (50.0%), respectively]. The region was identified as a significant predictor of use of intravenous methylprednisolone in MCD and MN patients. CONCLUSION: Use of intravenous methylprednisolone for MCD and MN differed geographically in Japan. Its efficacy should be further evaluated in a well-designed trial.

Two novel APOA1 gene mutations in a Japanese renal transplant recipient with recurrent apolipoprotein A-I related amyloidosis.

Apolipoprotein A-I amyloidosis is a rare, autosomal dominant disorder of APOA-1 gene characterized by the deposition of apolipoprotein A-I in various organs and can be classified into either hereditary or nonhereditary form in the absence of a family history. Renal disease caused by Apolipoprotein A-I amyloidosis commonly manifested as slowly progressive renal function impairment without heavy proteinuria. Apolipoprotein A-I-related amyloidosis of kidney is of pathogenetic interest because the renal failure is due to peritubular and interstitial amyloid deposits without glomerular deposits. Tubulointerstitial lesion of amyloid deposits was diagnosed in half of carriers of APOA1 gene mutation, only 13% of patients progressed to renal failure requiring hemodialysis or kidney transplantation. Recurrence of apolipoprotein A-I-related amyloidosis after kidney transplantation is very rare. We report a case of a 63-year-old Japanese female without a family history of kidney and/or liver disease who showed slowly progressive renal graft dysfunction without overt proteinuria. Graft biopsy revealed characteristic Congo red stain positive amyloid deposits localized in the renal interstitial area. No glomerular, vascular and tubular amyloid deposits were noted. Laser microdissection-liquid chromatography tandem mass spectrometry-based proteomic analysis elucidated the type of amyloidosis as apolipoprotein A-I amyloidosis. Genetic analysis of DNA sequence study revealed two novel APOA1 gene mutations of Leu202Arg and Lys262Asn. This is a first and very rare case report of the recurrence of non-familial hereditary apolipoprotein A-I amyloidosis in Japanese transplant recipient.

Favorable results in ABO-incompatible renal transplantation without B cell-targeted therapy: Advantages and disadvantages of rituximab pretreatment.

The effectiveness of desensitization with rituximab in ABO-incompatible renal transplantation (ABO-I) has been widely reported. However, ABO-I outcomes are still worse than those of ABO-identical or ABO-compatible renal transplantation (ABO-Id/C). We retrospectively examined the outcomes in consecutive living donor ABO-Id/C (n = 412) and ABO-I (n = 205) cases to elucidate the causes of inferiority in ABO-I. ABO-I cases included recipients treated with rituximab (RIT, n = 131), splenectomy (SPX, n = 21), or neither because of low anti-A/B antibody titers (NoR/S, n = 53). Graft survival, infection, and de novo HLA antibody production were compared for ABO-I and ABO-Id/C, followed by stratification into RIT and NoR/S groups. Propensity score-based methods were employed to limit selection bias and potential confounders. Overall graft survival for ABO-I was significantly lower than that for ABO-Id/C (92.8% vs 97.2% after 5 years, P = .0037). Graft loss due to infection with ABO-I was significantly more frequent than that with ABO-Id/C, whereas acute antibody-mediated rejection (AMR) caused no graft failure in ABO-I recipients. Stratified analysis demonstrated significantly higher infection risk with RIT than with NoR/S. Safe reduction or avoidance of rituximab in desensitization protocols might contribute to further improvement of ABO-I outcome.

Results of a multicenter prospective clinical study in Japan for evaluating efficacy and safety of desensitization protocol based on rituximab in ABO-incompatible kidney transplantation.

BACKGROUND: Deceased organ donations are rare in Japan, with most kidney transplants performed from a limited number of living donors. Researchers have thus developed highly successful ABO-incompatible transplantation procedures, emphasizing preoperative desensitization and postoperative immunosuppression. A recent open-label, single-arm, multicenter clinical study prospectively examined the efficacy and safety of rituximab/mycophenolate mofetil desensitization in ABO-incompatible kidney transplantation without splenectomy. METHODS: Mycophenolate mofetil and low dose steroid were started 28 days pretransplant, followed by two doses of rituximab 375 mg/m2 at day -14 and day -1, and postoperative immunosuppression with tacrolimus or ciclosporin and basiliximab. The primary endpoint was the non-occurrence rate of acute antibody-mediated rejection. Patient survival and graft survival were monitored for 1 year posttransplant. RESULTS: Eighteen patients received rituximab and underwent ABO-incompatible kidney transplantation. CD19-positive peripheral B cell count decreased rapidly after the first rituximab infusion and recovered gradually after week 36. The desensitization protocol was tolerable, and most rituximab-related infusion reactions were mild. No anti-A/B antibody-mediated rejection occurred with this series. One patient developed anti-HLA antibody-mediated rejection (Banff 07 type II) on day 2, which was successfully managed. Patient and graft survival were both 100 % after 1 year. CONCLUSION: Our desensitization protocol was confirmed to be clinically effective and with acceptable toxicities for ABO-I-KTx (University Hospital Medical Information Network Registration Number: UMIN000006635).

High Ferritin Level and Malnutrition Predict High Risk of Infection-Related Hospitalization in Incident Dialysis Patients: A Japanese Prospective Cohort Study.

AIMS: The aim of the study was to clarify the relationship between serum ferritin and infectious risks. METHODS: We evaluated all hospital admissions due to infections, clinical biomarkers and nutrition status in 129 incident Japanese dialysis patients during a median follow-up of 38 months. RESULTS: Kaplan-Meier analysis revealed that the period without infections requiring hospitalization was significantly shorter in ferritin > median (82.0 ng/ml) group than in the ferritin < median group (log-rank test 4.44, p = 0.035). High ferritin was associated with significantly increased relative risk of hospitalization for infection (Cox hazard model 1.52, 95% CI 1.06-2.17). The number of hospitalization days was gradually longer in patients with high ferritin levels and malnutrition. CONCLUSION: Although serum ferritin levels were low, and doses of iron administered to dialysis patients in Japan are generally lower than in Western countries, an elevated ferritin level was associated with increased risk of infection, particularly in patients with poor nutritional status.

Reviewing the pathogenesis of antibody-mediated rejection and renal graft pathology after kidney transplantation.

The clinicopathological context of rejection after kidney transplantation was well recognized. Banff conferences greatly contributed to elucidate the pathogenesis and to establish the pathologic criteria of rejection after kidney transplantation. The most important current problem of renal transplantation is de novo donor-specific antibody (DSA) production leading chronic rejection and graft loss. Microvascular inflammation is considered as a reliable pathological marker for antibody-mediated rejection (AMR) in the presence of DSA. Electron microscopic study allowed us to evaluate early changes in peritubular capillaries in T-lymphocyte mediated rejection and transition to antibody-mediated rejection. Severe endothelial injuries with edema and activated lymphocyte invaded into subendothelial space with early multi-layering of peritubular capillary basement membrane suggest T-lymphocyte mediated rejection induce an unbounded chain of antibody-mediated rejection. The risk factors of AMR after ABO-incompatible kidney transplantation are important issues. Anti-ABO blood type antibody titre of IgG excess 32-fold before transplant operation is the only predictable factor for acute AMR. Characteristics of chronic active antibody-mediated rejection (CAAMR) are one of the most important problems. Light microscopic findings and C4d stain of peritubular capillary and glomerular capillary are useful diagnostic criteria of CAAMR. Microvascular inflammation, double contour of glomerular capillary and thickening of peritubular capillary basement are good predictive factors of the presence of de novo DSA. C4d stain of linear glomerular capillary is a more sensitive marker for CAAMR than positive C4d of peritubular capillary. Early and sensitive diagnostic attempts of diagnosing CAAMR are pivotal to prevent chronic graft failure.

Ability of vitamin D receptor activator to prevent pulmonary congestion in advanced chronic kidney disease.

BACKGROUND: Vitamin D deficiency is common among patients with chronic kidney disease (CKD). However, the benefits of vitamin D supplementation versus vitamin D receptor activator (VDRA) administration have yet to be established. Recently, an association between activated vitamin D and cardiovascular factors was reported. To evaluate the benefits of VDRA in advanced CKD, we analyzed the association between VDRA administration and the prevalence of pulmonary congestion. METHODS: This retrospective, cross-sectional analysis included patients initiated on dialysis between October 2011 and September 2013 at 17 Japanese institutions. Data from 952 participants were analyzed using a multivariate logistic regression model and a linear regression model. We also analyzed subgroup data for groups classified by selection of peritoneal dialysis or hemodialysis. RESULTS: Of the 952 participants, 303 patients received VDRA. VDRA administration was associated with a low prevalence of pulmonary congestion in the multivariate logistic regression model (odds ratio [OR], 0.64; 95 % confidence interval [CI], 0.44-0.94; P = 0.02). There was no significant association between VDRA administration and systolic blood pressure, diastolic blood pressure, or pulse pressure. Subgroup analysis revealed a tendency that VDRA administration was associated with low prevalence of pulmonary congestion in both groups. CONCLUSIONS: In this study, VDRA administration was associated with a low prevalence of pulmonary congestion in patients initiated on dialysis. Appropriate VDRA administration may prevent pulmonary congestion.

Beneficial effects of preemptive kidney transplantation on calcium and phosphorus disorders in early post-transplant recipients.

BACKGROUND: Recently, preemptive kidney transplantation (PKT) has increased in Japan; however, the effects of PKT on calcium (Ca) and phosphorus (Pi) metabolism are poorly understood. METHODS: Thirty-two consecutive patients were enrolled in this study at Nagoya Daini Red Cross Hospital. Fifteen patients were in the PKT group and 17 patients were in the non-PKT group. Parameters of Ca and Pi metabolism, including fibroblast growth factor (FGF) 23 and intact parathyroid hormone, were measured before transplantation and 1, 3, and 24 weeks after transplantation. RESULTS: FGF 23 decreased dramatically in both groups after transplantation; however, FGF 23 before transplantation and at 1 and 3 weeks after transplantation was significantly lower in the PKT group than in the non-PKT group (p < 0.05). Although iPTH levels were higher in the PKT group than in the non-PKT group before transplantation, these levels were lower in the PKT group at 24 weeks after transplantation (p < 0.05). Corrected Ca was lower at 24 weeks in the PKT group (p < 0.05), whereas Pi was lower in the non-PKT group at 1 and 3 weeks (p < 0.05), but not significantly different at 24 weeks. Multivariate linear regression analysis revealed that FGF 23 before transplantation was the strongest predictor of Ca and Pi disorders in early post-transplant recipients. CONCLUSIONS: This study suggests that PKT has beneficial effects on Ca and Pi metabolism and pre-transplant FGF 23 levels are a good marker of post-transplant Ca and Pi metabolism disorders.

How to estimate kidney function in kidney transplant recipients with mild to moderate kidney impairment: comparison of estimated glomerular filtration (eGFR) values between creatinine-based GFR equations and cystatin C-based GFR equations for Japanese population.

BACKGROUND: With the recent increase in renal transplantations in Japan, accurate assessment of renal function is required. METHODS: This study included 73 patients who had undergone renal transplantation at Nagoya Daini Red Cross Hospital at least 6 months previously and had stable renal function for >3 months. Glomerular filtration rates (GFRs) were measured by inulin clearance (mGFR) and compared with estimated cystatin C-based GFRs (eGFRcys), estimated creatinine-based GFRs (eGFRcre) and their average values (eGFRave). RESULTS: mGFR was 43.3 ± 14.1 mL/min/1.73 m(2), eGFRcre was 39.6 ± 11.7, eGFRcys was 56.0 ± 17.1, and eGFRave was 47.8 ± 13.7 mL/min/1.73 m(2). Serum cystatin C was 1.39 ± 0.37 mg/L and serum creatinine was 1.58 ± 0.51 mg/dL. The correlation coefficients between mGFR and eGFRcre, eGFRcys, and eGFRave were 0.768, 0.831, and 0.841, respectively (P < 0.001, for all).The intraclass correlation coefficients were 0.754, 0.816, and 0.840, respectively (P < 0.001, for all).The mean differences between measured and estimated GFR values were 3.74 mL/min/1.73 m(2) with a root-mean square error (RMSE) of 9.06 for eGFRcre, +12.64 with RMSE of 9.48 for eGFRcys, and +4.45 with RMSE of 7.86 for eGFRave. Bland-Altman plots showed that eGFRcys overestimated GFR values compared with mGFR values in most cases and that eGFRave overestimated GFR values in 53 of 73 cases, whereas eGFRcre underestimated the values in 53 of 73 cases. CONCLUSION: eGFRave may be the best marker to estimate kidney function in Japanese renal transplant recipients with mildly reduced or normal kidney function.

Recurrent glomerular disease after kidney transplantation: an update of selected areas and the impact of protocol biopsy.

Recurrence of native kidney disease following kidney transplantation affects between 10% and 20% of patients, and accounts for up to 8% of graft failures. In a considerable number of recipients with transplant glomerulopathy, it is impossible to distinguish between recurrent and de novo types. An accurate estimate of the incidence of recurrence is difficult due to limitations in the diagnosis of recurrent glomerulonephritis. De novo glomerular lesions may be misclassified if histological confirmation of the patient's native kidney disease is lacking. Asymptomatic histological recurrence in renal allografts may be missed if protocol biopsies are not available. Studies based on protocol biopsy are pivotal to accurately estimate the incidence of recurrence. Many factors are known to influence recurrence of kidney disease after transplantation, including the type and severity of the original disease, age at onset, interval from onset to end-stage renal disease, and clinical course of the previous transplantation. Early recognition of recurrence is possible in several glomerular diseases. Factors such as the existence of circulating permeability factors, circulating urokinase receptor and anti-phospholipase A2 receptor antibody, as well as disorders of complement regulatory proteins like factor I mutation and factor H mutation factors are expected to be useful predictors of recurrence. Peculiar clinical course of atypical haemolytic uremic syndrome after kidney transplantation is an informative sign of recurrent glomerular disease. These factors play pivotal roles in the development of recurrence of certain types of glomerulopathies. Understanding the pathogenesis of recurrent glomerulonephritis is critical to optimize prevention as well as treat individual cases of recurrent glomerulonephritis. Subclinical recurrence of IgA nephropathy after kidney transplantation is well recognized. Only protocol biopsies of clinically silent recipient can provide the accurate prevalence of recurrent IgA nephropathy. The study of recurrent glomerulonephritis will contribute not only to improving long-term graft survival, but also to clarifying the pathogenesis of glomerulonephritis. Protocol biopsy is one the most effective methods for elucidating the pathogenesis of recurrent glomerulonephritis.

Early recurrence of active IgA nephropathy after kidney transplantation.

IgA nephropathy (IgAN) is recurrent after transplantation; however, its time of recurrence is unpredictable. To date, factors influencing IgAN recurrence have not been elucidated. We present a case of a 23-year-old man with end-stage renal disease (ESRD) who underwent living-related ABO-identical pre-emptive kidney transplantation (PEKT) using his 57-year-old mother as a donor. IgAN started when the patient was 19 years old, and renal biopsy revealed the usual pathological findings of IgAN. In spite of steroid therapy including steroid pulse and tonsillectomy, the patient developed nephrotic syndrome and progressed to ESRD in 4 years. Protocol biopsy on day 19 following PEKT revealed active recurrent IgAN. Nephrotic-range proteinuria and mild deterioration of kidney function developed regardless of strong immunosuppressive therapy such as steroid pulse, double filtration plasmapheresis and rituximab. We report a case of refractory IgAN that recurred 19 days after transplantation. This case is considered of value to elucidate factors leading to active IgAN recurrence.

A case of IgG4-positive plasma cell-rich tubulointerstitial nephritis in a kidney allograft mimicking IgG4-related kidney disease.

A 51-year-old woman received an ABO blood type-incompatible renal transplant. She was administered rituximab and basiliximab and underwent plasma exchanges for induction therapy, followed by administration of tacrolimus, mycophenolate mofetil and methylprednisolone as maintenance immunosupression therapy. A planned renal biopsy 2 years after transplantation revealed infiltration of plasma cells in the renal interstitium, although there was no 'storiform' fibrosis surrounding these cells. There were also no findings of rejection, BK virus nephropathy, or atypical plasma cells. Immunohistochemical stainings showed a large number of IgG4-positive plasma cells, most of which expressed kappa-type light chains. A CT scan showed a mass at the renal hilum. The serum IgG4 level was high. Based on these findings, the patient was suspected of having IgG4-related kidney disease. Nine months after the biopsy, her serum creatinine level increase to 1.56 mg/dL and the dose of methylprednisolone was therefore increased to 16 mg/day. Three months after this increase in steroid, a CT scan showed the hilum mass had disappeared. A follow-up biopsy 5 months later showed that infiltration of plasma cells in the renal interstitium had decreased markedly, although focal and segmental severely fibrotic lesions with IgG4-positive plasma cells were observed. Serum IgG4 levels decreased immediately after the increase in steroid dose and remained <100 mg/dL despite a reduction in methylprednisolone to 6 mg/day. Serum creatinine levels also remained stable at around 1.6 mg/dL. To our knowledge, this is the first report of IgG4-positive plasma cell-rich tubulointerstitial nephritis mimicking IgG4-related kidney disease after kidney transplantation.