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Renal AND Proteinuria [keywords]
- Inhibition of Thrombin-Activated Fibrinolysis Inhibitor Increases Survival in Experimental Kidney Fibrosis. [JOURNAL ARTICLE]
- J Am Soc Nephrol 2014 Nov 19.
Uncontrolled diabetes, inflammation, and hypertension are key contributors to progressive renal fibrosis and subsequent loss of renal function. Reduced fibrinolysis appears to be a feature of ESRD, but its contribution to the fibrotic program has not been extensively studied. Here, we show that in patients with CKD, the activity levels of serum thrombin-activated fibrinolysis inhibitor and plasmin strongly correlated with the degree of renal function impairment. We made similar observations in rats after subtotal nephrectomy and tested whether pharmacologic inhibition of thrombin-activated fibrinolysis inhibitor with UK-396082 could reduce renal fibrosis and improve renal function. Compared with untreated animals, UK-396082-treated animals had reduced glomerular and tubulointerstitial fibrosis after subtotal nephrectomy. Renal function, as measured by an increase in creatinine clearance, was maintained and the rate of increase in proteinuria was reduced in UK-396082-treated animals. Furthermore, cumulative survival improved from 16% to 80% with inhibition of thrombin-activated fibrinolysis inhibitor. Taken together, these data support the importance of the fibrinolytic axis in regulating renal fibrosis and point to a potentially important therapeutic role for suppression of thrombin-activated fibrinolysis inhibitor activity.
- A case of endocapillary proliferative glomerulonephritis with macrophages phagocytosing monoclonal immunoglobulin lambda light chain. [JOURNAL ARTICLE]
- Pathol Int 2014 Nov 19.
Multiple myeloma (MM) is a plasma-cell neoplasm that can cause renal disorders. Renal lesions in MM can present with a very rare pathological manifestation involving a specific monoclonal immunoglobulin (Ig). We report the case of a 33-year-old woman who had edema, fatigue, elevated serum creatinine levels, hypoalbuminemia, and hypercholesterolemia. She had persistent hematuria and proteinuria lasting 3 years. Serum protein electrophoresis showed an M-spike, and serum immunofixation demonstrated the presence of monoclonal IgG λ. She had proteinuria in the nephrotic range, and a monoclonal λ fragment was present on urine immunofixation. Renal biopsy showed proliferative glomerulonephritis with λ light chain and C3c deposition and inflammatory cell infiltration with CD68. Macrophage lysosomes contained λ light chains, suggesting their partial phagocytosis. She was diagnosed with symptomatic MM and was treated with bortezomib and dexamethasone and an autologous peripheral stem cell transplant conditioned with intravenous melphalan. She achieved a partial response with decreased serum monoclonal protein and improved renal function. This case may be categorized as a monoclonal gammopathy-associated proliferative glomerulonephritis. The biopsy finding of partially phagocytosed Ig λ light chains by macrophages is very rare; this pathological condition is similar to crystal-storing histiocytosis.
- BDNF repairs podocyte damage by microRNA-mediated increase of actin polymerization. [JOURNAL ARTICLE]
- J Pathol 2014 Nov 19.
Idiopathic Focal Segmental Glomerulosclerosis (FSGS) is a progressive and proteinuric kidney disease that starts with podocyte injury. Podocytes cover the external side of the glomerular capillary by a complex web of primary and secondary ramifications. Similar to dendritic spines of neuronal cells, podocyte processes rely on a dynamic actin-based cytoskeletal architecture to maintain shape and function. Brain Derived Neurotrophic Factor (BDNF) is a pleiotropic neurotrophin that binds to the tropomyosin-related kinase B receptor (TrkB) and has crucial roles in neuron maturation, survival, and activity. In neuronal cultures, exogenously added BDNF increases number and size of dendritic spines. In animal models, BDNF administration is beneficial in both central and peripheral nervous system disorders. Here we show that BDNF has a TrkB-dependent trophic activity on podocyte cell processes; by affecting microRNA-134 and microRNA-132 signaling, BDNF upregulates Limk1 translation and phosphorylation, and increases cofilin phosphorylation which results in actin polymerization. Importantly, BDNF effectively repairs podocyte damage "in vitro", and contrasts proteinuria and glomerular lesions in "in vivo" models of FSGS, opening a potential new perspective to the treatment of podocyte disorders.
- Neph1 is reduced in primary focal segmental glomerulosclerosis, minimal change nephrotic syndrome, and corresponding experimental animal models of adriamycin-induced nephropathy and puromycin aminonucleoside nephrosis. [Journal Article]
- Nephron Extra 2014 Sep; 4(3):146-54.
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.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.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.With nephrin (but not Neph1) unchanged in FSGS, there might be a disruption of the complex and an involvement of Neph1 in its pathogenesis.
- Gastrointestinal Inhibition of Sodium-Hydrogen Exchanger 3 Reduces Phosphorus Absorption and Protects against Vascular Calcification in CKD. [JOURNAL ARTICLE]
- J Am Soc Nephrol 2014 Nov 17.
In CKD, phosphate retention arising from diminished GFR is a key early step in a pathologic cascade leading to hyperthyroidism, metabolic bone disease, vascular calcification, and cardiovascular mortality. Tenapanor, a minimally systemically available inhibitor of the intestinal sodium-hydrogen exchanger 3, is being evaluated in clinical trials for its potential to (1) lower gastrointestinal sodium absorption, (2) improve fluid overload-related symptoms, such as hypertension and proteinuria, in patients with CKD, and (3) reduce interdialytic weight gain and intradialytic hypotension in ESRD. Here, we report the effects of tenapanor on dietary phosphorous absorption. Oral administration of tenapanor or other intestinal sodium-hydrogen exchanger 3 inhibitors increased fecal phosphorus, decreased urine phosphorus excretion, and reduced [(33)P]orthophosphate uptake in rats. In a rat model of CKD and vascular calcification, tenapanor reduced sodium and phosphorus absorption and significantly decreased ectopic calcification, serum creatinine and serum phosphorus levels, circulating phosphaturic hormone fibroblast growth factor-23 levels, and heart mass. These results indicate that tenapanor is an effective inhibitor of dietary phosphorus absorption and suggest a new approach to phosphate management in renal disease and associated mineral disorders.
- Decrease in Urinary Creatinine Excretion in Early Stage Chronic Kidney Disease. [JOURNAL ARTICLE]
- PLoS One 2014; 9(11):e111949.
Little is known about muscle mass loss in early stage chronic kidney disease (CKD). We used 24-hour urinary creatinine excretion rate to assess determinants of muscle mass and its evolution with kidney function decline. We also described the range of urinary creatinine concentration in this population.We included 1072 men and 537 women with non-dialysis CKD stages 1 to 5, all of them with repeated measurements of glomerular filtration rate (mGFR) by 51Cr-EDTA renal clearance and several nutritional markers. In those with stage 1 to 4 at baseline, we used a mixed model to study factors associated with urinary creatinine excretion rate and its change over time.Baseline mean urinary creatinine excretion decreased from 15.3±3.1 to 12.1±3.3 mmol/24 h (0.20±0.03 to 0.15±0.04 mmol/kg/24 h) in men, with mGFR falling from ≥60 to <15 mL/min/1.73 m2, and from 9.6±1.9 to 7.6±2.5 (0.16±0.03 to 0.12±0.03) in women. In addition to mGFR, an older age, diabetes, and lower levels of body mass index, proteinuria, and protein intake assessed by urinary urea were associated with lower mean urinary creatinine excretion at baseline. Mean annual decline in mGFR was 1.53±0.12 mL/min/1.73 m2 per year and that of urinary creatinine excretion rate, 0.28±0.02 mmol/24 h per year. Patients with fast annual decline in mGFR of 5 mL/min/1.73 m2 had a decrease in urinary creatinine excretion more than twice as big as in those with stable mGFR, independent of changes in urinary urea as well as of other determinants of low muscle mass.Decrease in 24-hour urinary creatinine excretion rate may appear early in CKD patients, and is greater the more mGFR declines independent of lowering protein intake assessed by 24-hour urinary urea. Normalizing urine analytes for creatininuria may overestimate their concentration in patients with reduced kidney function and low muscle mass.
- Systemic lupus erythematosus as the concomitant manifestation of angioimmunoblastic T-cell lymphoma. [JOURNAL ARTICLE]
- Mod Rheumatol 2014 Nov 17.:1-4.
Herein we report a case of the simultaneous occurrence of angioimmunoblastic T-cell lymphoma (AITL) and systemic lupus erythematosus (SLE) in a 76-year-old woman. She presented with fever, night sweats, and general malaise. A laboratory examination revealed leukopenia, anemia, polyclonal hypergammaglobulinemia, hypocomplementemia, positive results for anti-nuclear antibodies and anti-double strand DNA (anti-dsDNA) antibodies, and mild proteinuria. A computed tomography scan of the abdominal cavity showed multiple swollen intra-abdominal and intra-pelvic lymph nodes. A biopsy specimen obtained from the peri-iliac lymph node confirmed the diagnosis of AITL, while renal biopsy results were consistent with lupus nephritis, International Society of Nephrology and Renal Pathology Society class V. These results indicated that our patient developed SLE concomitantly with AITL. These findings will lead to further understanding of the pathogenic mechanism of SLE.
- IgA-dominant Postinfectious Glomerulonephritis Associated with Escherichia coli Infection Caused by Cholangitis. [Journal Article]
- Intern Med 2014; 53(22):2619-24.
A 76-year-old man with a history of type 2 diabetes mellitus was admitted with cholangitis caused by cholangiocarcinoma. Cholangitis with Escherichia coli (E. coli) bacteremia recurred due to the unstable bile drainage. At 1 month after recurrence, rapidly progressive glomerulonephritis with nephrotic syndrome was manifested. Renal biopsy findings were consistent with immunoglobulin A (IgA)-dominant postinfectious glomerulonephritis (PIGN). After ensuring that the recurrent cholangitis was controlled by drainage and antibiotic therapy, oral prednisolone was initiated, and the patient's renal function and proteinuria subsequently gradually improved. This is the first case report of IgA-dominant PIGN associated with cholangitis caused by E. coli infection.
- The kinetics of urinary shedding of BK virus in children with renal disease. [JOURNAL ARTICLE]
- Microbiol Immunol 2014 Nov 14.
Children with renal diseases are typically treated with immunosuppressive drugs, which place them at high risk for reactivation of the BK virus (BKV). Currently, not much is known about the impact of immunosuppressive drugs on the kinetics of urinary shedding of BKV and viral reactivation in pediatric patients with renal diseases. Urine samples were collected monthly for one year from twenty children (median age: 9 years, range: 4-15 years) with renal diseases and subjected to real-time PCR. Urinary shedding of BKV was detected in 35% (7/20) of the patients, with three patients having persistent viral DNA excretion (2 cases, 12 times; 1 case, 4 times) and four patients having intermittent viral DNA excretion. Thirty-four of the 240 urine samples contained BKV DNA (median copy numbers: 5.66 log copies/ml; range: 2.45 to 7.69 log copies/ml). In the two cases with persistent viral shedding, high copy numbers (range: 4.57 to 7.69 log copies/ml) of BKV DNA were detected in all 12 urine samples collected. In the other case with persistent viral excretion, a certain extent amount (range: 2.45 to 3.98 log copies/ml) of BKV DNA were detected in the four urine samples collected between the 9(th) and 12(th) sampling time points. Additionally, high copy numbers (range: 3.12 to 4.36 log copies/ml) of BKV DNA were detected intermittently in the urine samples of the four cases. No remarkable correlation was found between the kinetics of BKV DNA loads and urinary findings such as proteinuria and hematuria. The present data demonstrates the kinetics of urinary BKV shedding in pediatric patients with renal diseases. Additionally, no pathogenic role for BKV infection was identified.
- Glomerular Autoimmune Multicomponents of Human Lupus Nephritis In Vivo (2): Planted Antigens. [JOURNAL ARTICLE]
- J Am Soc Nephrol 2014 Nov 14.
Glomerular planted antigens (histones, DNA, and C1q) are potential targets of autoimmunity in lupus nephritis (LN). However, the characterization of these antigens in human glomeruli in vivo remains inconsistent. We eluted glomerular autoantibodies recognizing planted antigens from laser-microdissected renal biopsy samples of 20 patients with LN. Prevalent antibody isotypes were defined, levels were determined, and glomerular colocalization was investigated. Renal and circulating antibodies were matched, and serum levels were compared in 104 patients with LN, 84 patients with SLE without LN, and 50 patients with rheumatoid arthritis (RA). Autoantibodies against podocyte antigens (anti-α-enolase/antiannexin AI) were also investigated. IgG2 autoantibodies against DNA, histones (H2A, H3, and H4), and C1q were detected in 50%, 55%, and 70% of biopsy samples, respectively. Anti-DNA IgG3 was the unique non-IgG2 anti-DNA deposit, and anti-C1q IgG4 was mainly detected in subepithelial membranous deposits. Anti-H3, anti-DNA, and anti-C1q IgG2 autoantibodies were also prevalent in LN serum, which also contained IgG3 against the antigen panel and anti-C1q IgG4. Serum and glomerular levels of autoantibodies were not strictly associated. High serum levels of all autoantibodies detected, including anti-α-enolase and antiannexin AI, identified LN versus SLE and RA. Anti-H3 and anti-α-enolase IgG2 levels had the most remarkable increase in LN serum and represented a discriminating feature of LN in principal component analysis. The highest levels of these two autoantibodies were also associated with proteinuria>3.5 g/24 hours and creatinine>1.2 mg/dl. Our findings suggest that timely autoantibody characterization might allow outcome prediction and targeted therapies for patients with nephritis.