Podocyte-associated mRNA profiles in kidney tissue and in urine of patients with active lupus nephritis.

AIM: Glomerular deposition of immune complexes and inflammation induce podocyte injury in lupus nephritis (LN). This study hypothesized that the severity of the histological lesions of LN affects podocyte-associated mRNAs profiles in kidney tissue and in urine. METHODS: Thirty-three patients with LN were grouped according to the presence of mild mesangial (classes I and II) or moderate-to-severe immune complex deposition, proliferation and/or inflammation (classes III, IV and V) in kidney biopsy. Tissue and urine mRNA of nephrin, podocin, podocalyxin, α-actinin-4, transient receptor potential cation channel 6, and of growth factors VEGF-A and TGF-ß1 and the transcription factor FOXP3 were measured using real time polymerase chain reaction. These mRNAs were correlated with histological severity of LN, extent of glomerular immune deposits, and tissue infiltrating cells. RESULTS: Podocyte-associated mRNAs were inhibited in renal tissue of patients with LN irrespective of histological class when compared to controls. However, significantly higher expression of podocyte mRNAs in urine, including those of growth factors and FOXP3, were found in patients with moderate-to-severe nephritis, mostly in class III and IV proliferative forms. The number of invading CD8+ T cells, B cells and macrophages correlated positively with urine podocyte-associated mRNAs. Urine podocyte mRNAs also correlated with proteinuria. CONCLUSIONS: Inhibition of podocyte-associated mRNAs in kidney tissue suggests that podocyte injury occurs regardless of class severity of LN. Increased urinary excretion of podocyte mRNAs, mostly in patients with moderate-to-severe lesions, may reflect a greater burden of glomerular damage with detachment of podocytes into the urine.

Messenger RNA levels of podocyte-associated proteins in subjects with different degrees of glucose tolerance with or without nephropathy.

BACKGROUND: To investigate gene expression of podocyte-specific proteins in urine of diabetes and prediabetes subjects and the association of these proteins with albuminuria. METHODS: Fifteen controls, 19 prediabetes, and 67 diabetes subjects were included. Messenger RNA of nephrin, podocin, podocalyxin, synaptopodin, TRPC6, alpha-actinin-4, and TGF-ß1 were measured using RT-PCR. Podocyte marker expression was correlated with albuminuria, glycemic control, and renal function. The diagnostic performance of the genes used to detect increased albuminuria was assessed using ROC curves and Poisson regressions. RESULTS: Podocyte marker expression was significantly higher in diabetic subjects. Urinary nephrin was correlated with increasing levels of albuminuria; risk of albuminuria increased by 20% for every one-unit increase in the log10 of nephrin mRNA. Nephrinuria was found in 53%, 71%, and 90% of normo-, micro-, and macroalbuminuric diabetes subjects, respectively (p = 0.023). Urinary nephrin, podocalyxin, TRPC6, podocin, and alpha actinin-4 were correlated with glycemic control and albuminuria but not with renal function. CONCLUSIONS: Diabetes subjects had higher urinary mRNA levels of podocyte proteins than nondiabetic subjects, even the normoalbuminuric patients. Nephrinuria was correlated with diabetic nephrophathy stage and predicted pathological albuminuria. Urinary mRNA levels of podocyte markers of prediabetic subjects did not differ from controls.

Expression of fibrosis-related genes in human renal allografts with interstitial fibrosis and tubular atrophy.

BACKGROUND: Gene expression analysis of fibrosis-related genes may became useful for the early identification of fibrosis processes. We quantitatively assessed messenger RNA transcripts of the CTGF, TGF-ß and KIM-1 genes, in biopsy samples from renal transplant recipients with graft dysfunction, to test the hypothesis that in patients with chronic disease of the renal transplant, these molecules could be markers of the development and severity of graft fibrosis. METHODS: Ninety-six kidney transplant recipients who undertook 121 indication graft biopsies between January 2008 and December 2009 were included. Patients and biopsies were classified into 4 major diagnostic groups according to the Banff 2007 classification: acute tubular necrosis (ATN; n = 20), acute rejection (AR; n = 58), acute calcineurin inhibitor nephrotoxicity (CIN; n = 13) and interstitial fibrosis and tubular atrophy (IF/TA; n = 30). RESULTS: Messenger RNA transcripts of the CTGF and TGF-ß genes were significantly higher in IF/TA compared with all other conditions. Messenger RNA transcripts of the KIM-1 gene in the IF/TA group were higher than in the CIN group. In addition, it was observed that gene expression of CTGF, TGF-ß and KIM-1 increased with severity of fibrosis observed in the pathological examinations. CONCLUSIONS: Gene expression evaluation of the kidney graft tissue may be used to improve pathological diagnosis and perhaps for the future development of noninvasive biomarkers.

Effect of peripheral and respiratory muscle training on the functional capacity of hemodialysis patients.

Patients on hemodialysis (HD) show changes in muscle structure and function reducing their functional capacity. This study was conduted to assess the effects of respiratory muscle training (RMT) and peripheral muscle training (PMT) during dialysis on functional parameters, inflammatory state, and quality of life (QoL) in patients on HD. Randomized controlled trial included 39 patients on HD, and they were divided into three groups: RMT (n = 11), PMT (n = 14), and controls (C, n = 14). Training was performed during the HD session for 10 weeks. Maximal inspiratory pressure (PI(max)), maximal expiratory pressure (PE(max)), forced vital capacity (FVC), six-minute walk test (6MWT), Kt/V(sp), biochemical parameters, and inflammatory state (i.e., level of high sensitivity C-reactive protein) were evaluated. Variation from baseline was calculated by Analysis of Covariance (ANCOVA). The ΔPI(max) was 22.5 ± 3.2, 9.1 ± 2.9, and -4.9 ± 2.8 cmH(2)O in the RMT, PMT and C, respectively (p < 0.001); ΔPE(max) was 10.8 ± 6.6, 3.7 ± 5.9, and -15.6 ± 5.9 cmH(2)O respectively (p = 0.014). The Δ6MWT was significantly greater in RMT and PMT (65.5 ± 9; 30.8 ± 8 m) than in C (-0.5 ± 8.1 m), p < 0.001. Although biochemical parameters decreased after training, Kt/V remained unchanged. CRP decreased only in the RMT and PMT groups. There was a significant increase in QoL scores in the training groups (vs. C) in energy/fatigue (p = 0.002), sleep (p < 0.001), pain (p < 0.001), and list of symptoms/problems (p = 0.014). A short period of RMT or PMT during HD significantly improved functional capacity, with RMT showing greater effect than PMT. Muscle training improved biochemical and inflammatory markers, but a direct cause and effect relationship could not be established by this study.

Acute effect of simvastatin on inflammation and oxidative stress in chronic kidney disease.

BACKGROUND: Inflammation and oxidative stress (OS) are risk factors for cardiovascular disease in chronic kidney disease (CKD). This study assessed the acute effect of simvastatin on inflammatory and OS markers in stage 3 and 4 CKD patients. METHODS: Randomized, placebo-controlled, double-blind, cross-over study comprising 66 patients who were randomized to simvastatin (20 mg/day) or placebo for two 8-week periods. Glomerular filtration rate (GFR), lipid profile, C-reactive protein (CRP), fibrinogen, carbonyls and total radical-trapping antioxidant potential (TRAP) were measured. Interactions between potential confounding factors, such as diabetes mellitus, malnutrition, drug use, hypercholesterolemia and treatment response were assessed through the course of inflammatory and OS levels. RESULTS: Thirty-three patients were randomized to simvastatin/placebo (S-P), and 33 to placebo/simvastatin (P-S). Simvastatin significantly reduced total and LDL cholesterol (pretreatment vs. posttreatment: p=0.0001 and p=0.0001, respectively) in both periods. No differences were seen in CRP, fibrinogen, carbonyls and TRAP levels between S-P and P-S groups at the end of the 2 study periods. GFR was similar in both groups and negatively correlated to fibrinogen (r=-0.25, p=0.04) and TRAP (r=-0.27, p=0.03). No interactions were found between confounding factors and response to simvastatin. There was no interference of either a period effect or any carryover effect on study results. CONCLUSIONS: The use of simvastatin in CKD patients acutely did not reduce serum inflammation or OS markers. Possibly higher doses and/or longer treatment course of statin are required to produce drug pleiotropic effects in nondialysis CKD patients.

Prevalence and immunohistochemical findings of subclinical kidney allograft rejection and its association with graft outcome.

Subclinical acute rejection (SAR) occurs in about 30% of stable renal transplant patients and may be a risk factor for a poor allograft outcome. In the present study, the prevalence and clinical features of subclinical rejection, and the expression of immune activation markers in surveillance graft biopsies were assessed and correlated with late graft outcomes. Protocol biopsies were obtained at 2 and 12 months post-transplant in 32 and 26 patients, respectively, with stable renal function. The Banff 1997 criteria were used for histological diagnosis. Graft function and survival and proteinuria were assessed during the 36 months of follow-up. Immunohistochemical evaluation of cell subpopulations and immunoactivation markers were performed on protocol biopsies. The prevalence of SAR at 2 months and of chronic allograft nephropathy (CAN) at 12 months in representative biopsies was 55 and 50%, respectively. Patients with SAR presented mononuclear cell infiltration with an increased expression of CD3, CD4, CD68, IL-2R and granzyme B. Kidney graft function was significantly worse in patients with SAR at 2 months who had chronic rejection on biopsy at 12 months, but SAR was not associated with a worse graft function, greater proteinuria or a lower graft survival in 3 yr of follow-up. In conclusion, we found an elevated prevalence of SAR at 2 months after transplantation with an increased expression of activation markers. Although an association of SAR with poor graft outcome was not observed, our results suggest that SAR is an immunologically active process and underscore the importance of protocol biopsies in the surveillance of transplanted kidneys.

Hipercalciúria Idiopática; Fisiopatologia e diagnóstico diferencial / Idiopathic hypercalciuria: pathophysiology and diferential diagnosis

A hipercalciúria idiopática é a normalidade metabólica mais prevalente na litíase do cálcio. É caracterizada por hipercalciúria persistente e normocalcemia. Existem quatro mecanismos envolvidos em sua fisiopatogênese: hiperabsorçäo intestinal de cálcio, hipercalciúria renal, perda tubular primária de fosfato e distúrbio na regulaçäo da vitamina D. O método diagnóstico mais empregado para diferenciar as formas absortiva e renal é o teste de sobrecarga oral de cálcio. O tratamento adequado e específico dos diferentes tipos pode prevenir ou diminuir a recorrência de cálculos. É possível que a produçäo excessiva de vitamina D3 pelo rim seja o fator inicial na gênese da hipercalciúria idiopática