Rui Toledo Barros

FGF-23 as a Predictor of Renal Outcome in Diabetic Nephropathy

BACKGROUND AND OBJECTIVES Fibroblast growth factor 23 (FGF-23) has emerged as a new factor in mineral metabolism in chronic kidney disease (CKD). An important regulator of phosphorus homeostasis, FGF-23 has been shown to independently predict CKD progression in nondiabetic renal disease. We analyzed the relation between FGF-23 and renal outcome in diabetic nephropathy (DN). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS DN patients participating in a clinical trial (enalapril+placebo versus enalapril+losartan) had baseline data collected and were followed until June 2009 or until the primary outcome was reached. Four patients were lost to follow-up. The composite primary outcome was defined as death, doubling of serum creatinine, and/or dialysis need. RESULTS At baseline, serum FGF-23 showed a significant association with serum creatinine, intact parathyroid hormone, proteinuria, urinary fractional excretion of phosphate, male sex, and race. Interestingly, FGF-23 was not related to calcium, phosphorus, 25OH-vitamin D, or 24-hour urinary phosphorus. Mean follow-up time was 30.7±10 months. Cox regression showed that FGF-23 was an independent predictor of the primary outcome, even after adjustment for creatinine clearance and intact parathyroid hormone (10 pg/ml FGF-23 increase = hazard ratio, 1.09; 95% CI, 1.01 to 1.16, P=0.02). Finally, Kaplan-Meier analysis showed a significantly higher risk of the primary outcome in patients with FGF-23 values of >70 pg/ml. CONCLUSIONS FGF-23 is a significant independent predictor of renal outcome in patients with macroalbuminuric DN. Further studies should clarify whether this relation is causal and whether FGF-23 should be a new therapeutic target for CKD prevention.

Urinary MCP-1 and RBP: independent predictors of renal outcome in macroalbuminuric diabetic nephropathy.

BACKGROUND Albuminuria has been considered a sine qua non condition for the diagnosis of diabetic nephropathy (DN) and has been widely used as a surrogate outcome of chronic kidney disease (CKD). However, recent data suggest that albuminuria may fail as a biomarker in a subset of patients, and the search for novel markers is intense. METHODS We analyzed the role of urinary RBP and of serum and urinary cytokines (TGF-beta, MCP-1 and VEGF) as predictors of the risk of dialysis, doubling of serum creatinine or death (primary outcome, PO) in 56 type 2 diabetic patients with macroalbuminuric DN. RESULTS Mean follow-up time was 30.7±10 months. Urinary RBP and MCP-1 were significantly higher in patients presenting the PO, whereas no difference was shown for TGF-β or VEGF. In the Cox regression, urinary RBP, MCP-1 and VEGF were positively associated and serum VEGF was inversely related to the risk of the PO. However, after adjustments for creatinine clearance, proteinuria, and blood pressure only urinary RBP (OR 11.6; 95% CI 2.7-49.2, p=0.001 for log RBP) and urinary MCP-1 (OR 11.0; 95% CI 1.6-76.4, p=0.02 for log MCP-1) remained as significant independent predictors of the PO. CONCLUSION Urinary RBP and MCP-1 are independently related to the risk of CKD progression in patients with macroalbuminuric DN. Whether these biomarkers have a role in the setting of normoalbuminuria and microalbuminuria in DN should be further investigated.

Association of the MCP-1 −2518 A/G Polymorphism and No Association of Its Receptor CCR2 −64 V/I Polymorphism with Lupus Nephritis

Objective. To evaluate whether the A/G polymorphism at position −2518 in the regulatory region of the monocyte chemoattractant protein-1 (MCP-1) or the V/I polymorphism at position −64 of the receptor, CCR2, are associated with lupus nephritis (LN) or any clinical characteristics of the disease or with renal survival in a patient population. Methods. We selected 197 patients with lupus nephritis and 220 matched healthy controls for study. MCP-1 and CCR2 genotyping was performed by polymerase chain reaction. Clinical and laboratory data were compiled from patients’ charts over followup that ranged from 6 months to 10 years. Results. The G/G genotype of MCP-1 was more common in LN patients (p = 0.019), while the A allele was associated with healthy controls (p = 0.007) as was the V allele of CCR2 (p = 0.046) compared to LN patients. Clinical index measures [SLE Disease Activity Index (SLEDAI)], immunological markers, renal histology, renal function at enrollment, and renal survival were not influenced by these polymorphisms. A less aggressive renal disease, measured by renal SLEDAI index, was associated with the V allele of the CCR2 gene polymorphism. Conclusion. These findings support that MCP-1 −2518 G/G is associated with LN but there was no association of this genotype with renal function or renal survival. When studying CCR2 −64 V/I polymorphism we showed a positive association of the V allele with healthy controls but no association of the genotype with LN patients.

Antibodies to ribosomal P proteins in lupus nephritis: a surrogate marker for a better renal survival?

OBJECTIVE To define if antibodies to ribosomal P proteins disclose a better lupus nephritis long-term survival. METHODS Sixty consecutive SLE patients with biopsy-proven nephritis (2004 ISN/RPS) were evaluated for renal survival parameters. Inclusion criteria were at least one serum sample at: renal flares, biopsy, and last follow-up until 2008. Anti-P was detected by ELISA/immunoblot and anti-dsDNA by indirect immunofluorescence/ELISA. RESULTS Eleven patients (18%) with anti-P+ (without anti-dsDNA) during renal flare were compared to 49 (82%) persistently negative for anti-P throughout the study. At the final follow-up post-biopsy (6.3±2.5 vs. 6.8±2.4 years, p=0.36), the comparison of anti-P+/anti-dsDNA- with anti-P- group revealed a trend to lower mean creatinine levels (0.9±0.3 vs. 2.3±2.1 mg/dl, p=0.07), lower frequency of dialysis (0% vs. 35%, p=0.025), and higher frequency of normal renal function (91% vs. 53%, p=0.037). The overall renal survival was significantly higher in anti-P+/anti-dsDNA- compared to anti-P- (11.0±4.5 vs. 9.2±4.5 years, p=0.033), anti-dsDNA+/anti-P- (vs. 8.7±4.7 years, p=0.017), and anti-P-/anti-dsDNA- (vs. 9.8±4.3 years, p=0.09) groups. CONCLUSION Our data supports the notion that anti-P antibody in the absence of anti-dsDNA during nephritis flares is a valuable marker to predict a better long-term renal outcome in lupus patients.

Biopsy Proven Acute Tubular Necrosis Due to Rhabdomyolysis in a Dengue Fever Patient: a Case Report and Review of Literature

Renal histology results are very scarce in dengue-associated rhabdomyolysis patients developing acute kidney injury (AKI). We report a case of dengue fever-induced AKI associated to rhabdomyolysis with a renal biopsy showing acute tubular necrosis (ATN) and renal deposition of myoglobin. A 28-year-old patient who presented dengue fever (DF) complicated by severe AKI and rhabdomyolysis is described. The patient required hemodialysis for three weeks. A renal biopsy revealed ATN with positive staining for myoglobin in the renal tubuli. The patient was discharged with recovered renal function. In conclusion, this case report described a biopsy proven ATN associated to DF-induced rhabdomyolysis, in which renal deposition of myoglobin was demonstrated. We suggest that serum creatine phosphokinase should be monitored in DF patients to allow for an early diagnosis of rhabdomyolysis and the institution of renal protective measures.

MYH9 and APOL1 Gene Polymorphisms and the Risk of CKD in Patients with Lupus Nephritis from an Admixture Population

MYH9 polymorphisms have been described to be associated with the risk of CKD in non-diabetic nephropathy, HIV nephropathy and FSGS. Predominating in black descendants, MHY9 genetic variants could partially explain the excess risk of CKD associated with African ancestry. However, recent data suggests that APOL1 gene co-segregate with MYH9, and could be the gene truly associated with CKD risk. In this study, we evaluated the role of MYH9 and APOL1 gene polymorphisms in the risk of CKD in Brazilian patients with lupus nephritis (LN). A retrospective analysis of 196 LN patients was done. MYH9 rs4821480, rs2032487, rs4821481 and rs3752462, APOL 1rs73885319, rs16996616, rs60910145, rs71785313, and APOL3 rs11089781 gene polymorphisms were determined. Genetic ancestry was ascertained both by autossomal ancestry and mitochondrial haplogroup. Primary outcome was defined as doubling of serum creatinine (DC) or end stage renal disease (ESRD). Sixty-two patients presented the PO. In our population, MYH9 and APOL1 were not in LD. None APOL polymorphism was associated with the PO, whereas rs3752462 MYH9 polymorphism showed a positive association (HR3.72, 95%CI 1.47–9.38, p = 0.005). When we analyzed the MYH9 E1 haplotype, the GCCT carriers (1 or 2 alelles present in 29.7% in the PO group vs. 18.5% in controls) showed a significant association to the risk of PO, even after adjustments for baseline estimated creatinine clearance and autossomal ancestry (HR 2.0, 95%CI 1.2–3.4, p = 0.01). Our results show that in our population MYH9, but not APOL1, gene polymorphisms confer an increased risk of CKD in LN patients, independently of race.

Uso da internet como um ambiente para discussão de casos clínicos

An environment was built on the Internet for discussing clinical cases on the website of the Brazilian Society of Nephrology (http://www.sbn.org.br). The aim of this work is to present the operation of this system and the improvements made since its introduction in September 2001. Up to the present moment, 62 cases have been published and diagnosed. All of them are stored in the website for consultation without any previous registration. The Internet also proved to be a promising environment for clinical-pathological discussion for allowing the participation of professionals from distant centers and without local conditions for this kind of activity of great importance for continuing education in Medicine.

Proteinuria predicts relapse in adolescent and adult minimal change disease

OBJECTIVE: This study sought to outline the clinical and laboratory characteristics of minimal change disease in adolescents and adults and establish the clinical and laboratory characteristics of relapsing and non-relapsing patients. METHODS: We retrospectively evaluated patients with confirmed diagnoses of minimal change disease by renal biopsy from 1979 to 2009; the patients were aged >13 years and had minimum 1-year follow-ups. RESULTS: Sixty-three patients with a median age (at diagnosis) of 34 (23-49) years were studied, including 23 males and 40 females. At diagnosis, eight (12.7%) patients presented with microscopic hematuria, 17 (27%) with hypertension and 17 (27%) with acute kidney injury. After the initial treatment, 55 (87.3%) patients showed complete remission, six (9.5%) showed partial remission and two (3.1%) were nonresponders. Disease relapse was observed in 34 (54%) patients who were initial responders (n = 61). In a comparison between the relapsing patients (n = 34) and the non-relapsing patients (n = 27), only proteinuria at diagnosis showed any significant difference (8.8 (7.1-12.0) vs. 6.0 (3.6-7.3) g/day, respectively, p = 0.001). Proteinuria greater than 7 g/day at the initial screening was associated with relapsing disease. CONCLUSIONS: In conclusion, minimal change disease in adults may sometimes present concurrently with hematuria, hypertension, and acute kidney injury. The relapsing pattern in our patients was associated with basal proteinuria over 7 g/day.

Tuberculosis-Associated Collapsing Glomerulopathy: Remission after Treatment

Collapsing glomerulopathy (CG) is a severe form of nephrotic syndrome and has been mostly associated with human immunodeficiency virus (HIV) infection. Treatment response is poor, and the disease frequently leads to end-stage renal disease. More recently, CG has been described in association with other conditions, such as drug exposure and other infections, but renal prognosis remains unfavorable. This paper reports an interesting case of an HIV-negative patient with tuberculosis-related CG who needed dialysis for five months but presented full renal recovery after tuberculosis (TB) treatment and corticotherapy.

Lúpus eritematoso sistêmico: tratamento do acometimento sistêmico

DESCRICAO DO METODO DE COLETA DE EVIDENCIAS: Oito reumatologistas que trabalham em servicos que atendem grande numero de pacientes com lupus eritematoso sistemico, alguns dos quais tem pesquisa e publicacoes cientificas nesta area, foram convidados a participar do grupo de trabalho. Tambem foram convidados um nefrologista e uma dermatologista que atuam em grandes centros universitarios, com grande experiencia no atendimento destes pacientes. Todos se reuniram para discutir o tratamento das diferentes manifestacoes da doenca, subdivididos em quatro grupos de trabalho, cada qual ficando responsavel por buscar a melhor evidencia para o tratamento de um ou mais comprometimentos da doenca. A ultima edicao de Duboiss lupus erythematosus, editado por Wallace D e Hahn B, em 2001, foi utilizada como base da discussao. Trabalhos publicados nos ultimos cinco anos foram pesquisados no banco de dados do Medline. Devido a frequencia e a heterogeneidade de manifestacoes da doenca, a maioria dos trabalhos terapeuticos nao contempla grande casuistica, e nem sao randomicos e controlados. Como as manifestacoes e a gravidade da doenca variam em diferentes grupos populacionais, devemos avaliar com cuidado os estudos realizados em grupos populacionais distintos. GRAU DE RECOMENDACAO E FORCA DE EVIDENCIA: A: Estudos experimentais e observacionais de melhor consistencia. B: Estudos experimentais e observacionais de menor consistencia. C: Relatos de casos (estudos nao controlados). D: Opiniao desprovida de avaliacao critica, baseada em consensos, estudos fisiologicos ou modelos animais. OBJETIVOS: Elaborar recomendacao baseada na melhor evidencia cientifica para o tratamento das diversas manifestacoes sistemicas do lupus eritematoso sistemico. CONFLITO DE INTERESSE: Nenhum conflito de interesse declarado.