Yuta Matsukuma

A J-shaped association between serum uric acid levels and poor renal survival in female patients with IgA nephropathy

Recently, low serum uric acid (SUA) levels and high SUA levels, have emerged as risk factors for cardiovascular disease, as well as for the incidence of acute kidney injury and chronic kidney disease (CKD). However, the effect of low SUA on the progression of CKD remains unclear. To evaluate the association between SUA and renal prognosis in patients with immunoglobulin A nephropathy (IgAN), one of the most common causes of CKD, we retrospectively followed 1218 patients who were diagnosed with primary IgAN by kidney biopsy between October 1979 and December 2010. Patients were divided into three groups on the basis of SUA level tertiles: low (L group), middle (M group) and high (H group) tertiles (<6.1, 6.1–7.0, and >7.0 mg dl−1, respectively, for men and <4.4, 4.4–5.3, and >5.3 mg dl−1, respectively, for women). The risk factors for developing end-stage renal disease (ESRD) were estimated using a Cox proportional hazards model. After a median follow-up of 5.1 years, 142 patients (11.7%) developed ESRD. The hazard ratio (95% confidence interval) showed a J-shaped trend with the tertiles in both men (1.18 (0.55–2.54), 1.00 (reference), and 1.80 (1.01–3.10) in L, M and H groups, respectively) and women (2.73 (1.10–6.76), 1.00 (reference) and 2.49 (1.16–5.34) in L, M and H groups, respectively). Notably, low SUA was significantly associated with incident ESRD in women. This finding suggests that SUA has a J-shaped association with ESRD in patients with IgAN, especially women.

Temporal serum creatinine increase and exacerbation of tubulointerstitial inflammation during the first two months in resolving polyomavirus BK nephropathy

Polyomavirus BK nephropathy (BKVN) is an important complication in kidney transplantation. After immunosuppressive agents are reduced, some patients experience a temporal increase in serum creatinine (sCr) before viral clearance. The histological characteristics of re‐biopsies were therefore investigated to evaluate the time course of remission.

Early Disappearance of Urinary Decoy Cells in Successfully Treated Polyomavirus BK Nephropathy

BACKGROUND Polyomavirus BK nephropathy (BKVN) is an important infectious complication in kidney transplant patients. Regular screening using polymerase chain reaction for BK virus DNA in plasma and urinary cytology is effective for early diagnosis of BKVN. However, methods of follow-up and therapeutic targets are not well described. METHODS Ten patients with BKVN who received biweekly urinary cytology and repeat biopsies after diagnosis were retrospectively studied. Histological remission of BKVN was determined when biopsy revealed negative SV40 large T-antigen (TAg) staining. Results of urinary cytology and repeat biopsy findings were compared. RESULTS Urinary decoy cells disappeared in 8 of 10 patients 55 ± 25 (range 13-79) days after index biopsies. In those cases, allograft function was preserved and the final serum creatinine level was 2.14 ± 1.19 (0.80-4.55) mg/dL after 962 ± 393 (325-1563) days of follow-up. Two cases with persistent urinary decoy cells shedding lost their graft 195 and 362 days later. Amongst 29 repeat biopsies, there were 13 TAg-positive and 16 negative biopsies. In 12 of 13 TAg-positive biopsies (92%), urinary decoy cells were still positive, whereas at the same time in 15 TAg-negative biopsies, decoy cells had already disappeared (94%). CONCLUSIONS Cytology testing is advantageous because of its cost effectiveness. Clearance of decoy cells from urine was closely related to histological remission of BKVN, and may possibly be a therapeutic target in BKVN.

Light chain deposition disease in an older adult patient successfully treated with long-term administration of bortezomib, melphalan and prednisone

A 70-year-old woman was admitted to our hospital because of fatigue and renal dysfunction and was diagnosed with light chain deposition disease (LCDD) with multiple organ involvement (kidney, thyroid gland, heart and eyes). After chemotherapy with bortezomib, cyclophosphamide and dexamethasone, hepatobiliary enzyme levels increased abruptly. A liver biopsy showed light chain deposition in Disse spaces. After two years of treatment with bortezomib, melphalan and prednisone (VMP) administered at shorter intervals relative to regular cycles, the patient showed a hematological and organ response. This case indicates that a relatively low dose intensity VMP regimen is preferable for elderly patients with LCDD with multiple organ involvement.

Study on Dialysis Session Length and Mortality in Maintenance Hemodialysis Patients: The Q-Cohort Study

Objectives: Hemodialysis (HD) time has been recognized as an important factor in dialysis adequacy. However, few studies have reported on associations between HD time and prognosis among maintenance HD patients. We present some findings from a prospective cohort study, the Q-Cohort Study, which was set up to explore risk factors for mortality in Japanese HD patients. We hypothesized that HD ≥5 h was associated with a significant survival advantage compared with HD < 5 h. The present study examined association between HD time and mortality in Japanese HD patients. Methods: The prospective multicenter Q-Cohort Study was conducted between December 2006 and December 2010, following 3,456 Japanese HD patients for 4 years. We examined the association between HD time and prognosis using Cox proportional hazards modeling. Propensity scores were calculated using logistic regression. Results: During follow-up, 566 patients died from any cause. Patients with HD ≥5 h (n = 2,141) showed significantly lower risk of all-cause death (hazards ratio = 0.82; 95% CI 0.68–0.99) than those with HD < 5 h (n = 1,315), after adjusting for confounding risk factors. This association remained significant using a propensity score-based approach. After stratifying the analysis by patient age in 10-year increments, this finding remained significant only in patients who were ≥80 years of age. Conclusion: Our results suggest that HD ≥5 h has a more favorable effect on mortality than HD < 5 h.

Effect of steroid pulse therapy on post-transplant immunoglobulin A nephropathy.

Recent studies have suggested that patients with post‐transplant immunoglobulin A nephropathy have poor graft survival. There is limited research on the therapeutic effectiveness for post‐transplant immunoglobulin A nephropathy, especially steroid pulse therapy. The present study evaluated the efficacy of steroid pulse therapy on post‐transplant immunoglobulin A nephropathy.

A case of bacterial peritonitis caused by Roseomonas mucosa in a patient undergoing continuous ambulatory peritoneal dialysis

Bacterial peritonitis remains a life-threatening complication of peritoneal dialysis (PD). Roseomonas is a bacterial genus of pink-pigmented, oxidized, gram-negative coccobacilli that was first named in 1993. Importantly, Roseomonas mucosa exhibits antibiotic resistance, with significant resistance to cephalosporin, which is often selected as an empirical antibiotic regimen for peritonitis in PD patients. We herein report the case of a PD patient with bacterial peritonitis caused by Roseomonas mucosa that was fortunately identified using 16S rRNA gene sequencing and successfully treated with ciprofloxacin. Given that Roseomonas demonstrates resistance to a variety of antibiotics. The administration of empiric antibiotic therapy based on the recommendation of the International Society of Peritoneal Dialysis guidelines occasionally fails, leading to the aggravation of bacterial peritonitis. Hence, nephrologists should consider Roseomonas as one of the potential causative organisms of peritonitis, especially when gram-negative bacilli are resistant to cephalosporin and cannot be identified using standard laboratory methods.