We present the first report of a case of fibrillary glomerulonephritis (FGN) associated with thrombotic microangiopathy (TMA) and anti-glomerular basement membrane antibody (anti-GBM antibody). A 54-year-old man was admitted to our hospital for high fever and anuria. On the first hospital day, we initiated hemodialysis for renal dysfunction. Laboratory data revealed normocytic-normochromic anemia with schistocytes in the peripheral smear, thrombocytopenia, increased serum lactate dehydrogenase, decreased serum haptoglobin, and negative results for both direct and indirect Coombs tests. Based on these results, we diagnosed TMA. Assays conducted several days later indicated a disintegrin-like and metalloprotease with a thrombospondin motif 13 (ADAMTS13) activity of 31.6%, and ADAMTS13 inhibitors were negative. We started plasma exchange using fresh frozen plasma and steroid pulse therapy. Anti-GBM antibody was found to be positive. Renal biopsy showed FGN. Blood pressure rose on the 46th hospital day, and mild convulsions developed. Based on magnetic resonance imaging of the head, the patient was diagnosed with reversible posterior leukoencephalopathy syndrome. Hypertension persisted despite administration of multiple antihypertensive agents, and the patient experienced a sudden generalized seizure. Computed tomography of the head showed multiple cerebral hemorrhages. However, his blood pressure subsequently decreased and the platelet count increased. TMA remitted following 36 plasma exchange sessions, but renal function was not restored, and maintenance hemodialysis was continued. The patient was discharged on the 119th day of hospitalization. In conclusion, it was shown that TMA, FGN and anti-GBM antibody were closely related.
Background/aims: Tumor necrosis factor (TNF)-α is believed to play a role in diabetic kidney disease. This study explores the specific effects of TNF-α with regard to nephropathy-relevant parameters in the podocyte.
Methods: Cultured mouse podocytes were treated with recombinant TNF-α and assayed for production of monocyte chemoattractant protein-1 (MCP-1) by enzyme-linked immunosorbent assay (ELISA). TNF-α signaling of MCP-1 was elucidated by antibodies against TNF receptor (TNFR) 1 or TNFR2 or inhibitors of nuclear factor-kappaB (NF-κB), phosphatidylinositol 3-kinase (PI3K) or Akt. In vivo studies were done on male db/m and type 2 diabetic db/db mice. Levels of TNF-α and MCP-1 were measured by RT-qPCR and ELISA in the urine, kidney and plasma of the two cohorts and correlated with albuminuria.
Results: Podocytes treated with TNF-α showed a robust increase (∼900%) in the secretion of MCP-1, induced in a dose- and time-dependent manner. Signaling of MCP-1 expression occurred through TNFR2, which was inducible by TNF-α ligand, but did not depend on TNFR1. TNF-α then proceeded via the NF-κB and the PI3K/Akt systems, based on the effectiveness of the inhibitors of those pathways. For in vivo relevance to diabetic kidney disease, TNF-α and MCP-1 levels were found to be elevated in the urine of db/db mice but not in the plasma.
Conclusion: TNF-α potently stimulates podocytes to produce MCP-1, utilizing the TNFR2 receptor and the NF-κB and PI3K/Akt pathways. Both TNF-α and MCP-1 levels were increased in the urine of diabetic db/db mice, correlating with the severity of diabetic albuminuria.
Background: Little is known about the effect of low-density lipoprotein (LDL) cholesterol, triglyceride (TG), and high-density lipoprotein (HDL) cholesterol levels on renal function decline in patients receiving specialized pre-dialysis care.
Methods: In the prospective PREPARE-2 study, incident patients starting pre-dialysis care were included when referred to one of the 25 participating Dutch specialized pre-dialysis outpatient clinics (2004-2011). Clinical and laboratory data were collected every 6 months. A linear mixed model was used to compare renal function decline between patients with LDL cholesterol, TG, or HDL cholesterol levels above and below the target goals (LDL cholesterol: <2.50 mmol/l, TG: <2.25 mmol/l, and HDL cholesterol: ≥1.00 mmol/l). Additionally the HDL/LDL cholesterol ratio was investigated (≥0.4).
Results: In our study population (n = 306), the median age was 69 years and 70% were male. Patients with LDL cholesterol levels above the target of 2.50 mmol/l experienced an accelerated renal function decline compared to patients with levels below the target (crude additional decline: 0.10 ml/min/1.73 m(2)/month, 95% CI 0.00-0.20; p < 0.05). A similar trend was found for TG levels above the target of 2.25 mmol/l (0.05 ml/min/1.73 m(2)/month, 95% CI -0.06 to 0.16) and for a HDL/LDL cholesterol ratio below 0.4 (0.06 ml/min/1.73 m(2)/month, 95% CI -0.05 to 0.18). Adjustment for potential confounders resulted in similar results, and the exclusion of patients who were prescribed lipid-lowering medication (statin, fibrate, or cholesterol absorption inhibitor) resulted in a slightly larger estimated effect.
Conclusion: High levels of LDL cholesterol were associated with an accelerated renal function decline, independent of the prescription of lipid-lowering medication.
Background: Few studies have examined if infectious arteriovenous access complications vary with the cannulation technique and whether this is modified by dialysis frequency. We compared the infection rate between fistulas cannulated using buttonhole versus stepladder techniques for patients treated with short daily (SDH) or nocturnal hemodialysis at home (NHD). We also compared patients receiving conventional intermittent hemodialysis (CIHD) using stepladder cannulation.
Methods: Data were prospectively collected from 631 patients dialyzed with a fistula from 2001 to 2010 (Toronto and Ottawa, Canada). We compared the person-time incidence rate of bacteremia and local fistula infections using the exact binomial test.
Results: Forty-six (7.3%) patients received SDH (≥5 sessions/week, 2-4 h/session), 128 (20.3%) NHD (≥4 sessions/week, ≥5 h/session) and 457 (72%) CIHD (3 sessions/week, ≤4 h/session). Fifty percent of SDH and 72% of NHD patients used the buttonhole technique. There were 39 buttonhole-related bacteremias (rate: 0.196/1,000 fistula days) and at least 2 local buttonhole site infections. Staphylococcus aureus accounted for 85% of the bacteremias. There were 5 (13%) infection-related hospitalizations and 3 (10%) serious metastatic infections, including fistula loss. In comparison, there was 1 possible fistula-related infection in CIHD during follow-up (rate: 0.002/1,000 fistula days).
Conclusions: The rate of buttonhole-related infections was high among patients on frequent hemodialysis and more than 50 times greater than that among patients on CIHD with the stepladder technique. Most bacteremias were due to S. aureus - with serious consequences. The risks and benefits of buttonhole cannulation require individual consideration with careful monitoring, prophylaxis and management.
Bisphosphonates are commonly used for the treatment of osteoporosis, Paget's disease, multiple myeloma and hypercalcemia. Collapsing focal segmental glomerulosclerosis (FSGS) is known to occur uncommonly with exposure to bisphosphonates, specifically pamidronate and alendronate; it has rarely and equivocally been reported with zoledronate therapy. We describe the case of a 36-year-old African American female with metastatic breast cancer who presented with nephrotic-range proteinuria and acute kidney injury within 2 weeks of exposure to a single dose of zoledronate. The patient had a partial recovery of her renal function and showed improved proteinuria to a subnephrotic level after discontinuing zoledronate. In contrast to 2 prior reports of zoledronate-induced collapsing FSGS, the causative role of the exposure described here is certain. Our case necessitates the addition of zoledronate to the list of known causes of collapsing FSGS. Furthermore, it highlights the importance of periodically monitoring renal function and urine protein excretion with the use of zoledronate, which allows prompt diagnosis and withdrawal of the drug to increase the probability of renal recovery.
Background: Arteriovenous fistula is an uncommon complication of central venous catheterization that often requires invasive repair.
Case report: We report the case of an arteriovenous fistula that presented as ongoing pain following removal of a tunneled central venous catheter. The fistula resolved spontaneously following a period of compression and observation.
Conclusion: Our study highlights the etiology of this uncommon complication as well as suggesting a role for conservative management.
Background/aims: The transmembrane proteins Neph1 and nephrin form a complex in the slit diaphragm (SD) of podocytes. As recent studies indicate an involvement of this complex in the polymerization of the actin cytoskeleton and proteinuria, we wanted to study the subcellular localization of Neph1 in the normal human kidney and its expression in focal segmental glomerulosclerosis (FSGS), minimal change nephrotic syndrome (MCNS), and the corresponding experimental models of Adriamycin-induced nephropathy (ADR) and puromycin aminonucleoside nephrosis (PAN). All these disorders are characterized by substantial foot process effacement (FPE) and proteinuria.
Materials and methods: Kidney biopsies from patients with primary FSGS (perihilar type) and MCNS were compared to normal renal tissue. Mouse and rat kidney cortices from days 7 and 14 after Adriamycin injection and days 2 and 4 after puromycin aminonucleoside injection, respectively, were compared to control mouse and rat kidney. Polyclonal antibodies against Neph1 and nephrin were used for immunoelectron microscopy, and semiquantification was performed.
Results: We localized Neph1 mainly to, and in close proximity to, the SD. Double staining of Neph1 and nephrin showed the proteins to be in close connection in the SD. The total amount of Neph1 in the podocytes was significantly reduced in FSGS, MCNS, ADR, and PAN. The reduction of Neph1 was also seen in areas with and without FPE. Nephrin was reduced in MCNS and PAN but unchanged in FSGS.
Conclusion: With nephrin (but not Neph1) unchanged in FSGS, there might be a disruption of the complex and an involvement of Neph1 in its pathogenesis.
Uremic platelet dysfunction rarely causes significant bleeding in adequately dialyzed patients. When encountered, the management is complicated by a lack of well-supported treatment modalities. Estrogen use in uremic platelet dysfunction has been described, but enthusiasm for the treatment has been dampened by the risk of thrombotic events in vasculopathic dialysis patients. We present a patient on long-term peritoneal dialysis with coronary disease who developed recurrent life-threatening bleeding episodes secondary to uremia, where treatment with transdermal estrogen was used safely and effectively for a 24-month period.
Background/aims: Metabolic syndrome (MetS) may have an independent impact on the development of chronic kidney disease. This study examines the prevalence of MetS in subjects with IgA glomerulonephritis (IgAGN) and its impact on disease progression in a retrospective fashion.
Patients and methods: Altogether, 174 subjects (104 males) were examined 11 years (first visit) after IgAGN diagnosis and again after 16 years (second visit; 144 subjects responded). Different glomerular filtration markers were utilized. The MetS criteria by Alberti et al. [Circulation 2009;120:1640-1645] were applied, in which the presence of any three of five risk factors (elevated waist circumference, triglycerides, glucose, existence of hypertension, or reduced high-density lipoprotein cholesterol) constitutes the diagnosis.
Results: The prevalence of MetS at the first visit was 39%, corresponding to that of the general Finnish population. In univariate analyses, MetS was significantly associated with the progression of IgAGN at the second visit. However, in multivariate analyses, the existence of MetS was not a significant prognostic determinant.
Conclusion: The number of subjects with MetS among IgAGN patients and the general population is equal in Finland. MetS does not seem to be an independent prognostic variable.