Pharmacologic Blockade of αvß1 Integrin Ameliorates Renal Failure and Fibrosis In Vivo.

Activated fibroblasts are deemed the main executors of organ fibrosis. However, regulation of the pathologic functions of these cells in vivo is poorly understood. PDGF receptor ß (PDGFRß) is highly expressed in activated pericytes, a main source of fibroblasts. Studies using a PDGFRß promoter-driven Cre system to delete αv integrins in activated fibroblasts identified these integrins as core regulators of fibroblast activity across solid organs, including the kidneys. Here, we used the same PDGFRß-Cre line to isolate and study renal fibroblasts ex vivo We found that renal fibroblasts express three αv integrins, namely αvß1, αvß3, and αvß5. Blockade of αvß1 prevented direct binding of fibroblasts to the latency-associated peptide of TGF-ß1 and prevented activation of the latent TGF-ß complex. Continuous administration of a recently described potent small molecule inhibitor of αvß1, compound 8, starting the day of unilateral ureteral obstruction operation, inhibited collagen deposition in the kidneys of mice 14 days later. Compound 8 also effectively attenuated renal failure, as measured by BUN levels in mice fed an adenine diet known to cause renal injury followed by fibrosis. Inhibition of αvß1 integrin could thus hold promise as a therapeutic intervention in CKD characterized by renal fibrosis.

Kidney function and 24-hour proteinuria in patients with Fabry disease during 36 months of agalsidase alfa enzyme replacement therapy: a Brazilian experience.

BACKGROUND: Prior to the introduction of enzyme replacement therapy (ERT), management of Fabry disease (FD) consisted of symptomatic and palliative measures. ERT has been available for several years using recombinant human agalsidase alfa, an analogue of alpha-galactosidase A (GALA). However, the limitations of ERT in improving kidney function have not been established. This study evaluates the safety and therapeutic effect of agalsidase alfa replacement in terms of kidney function and reduction in 24-hour proteinuria. METHODS: During the period between January 1, 2002, and August 1, 2005, nine Fabry patients (7 male, 2 female) were treated according to protocol, receiving 0.2 mg/kg agalsidase alfa IV every two weeks. Kidney function was evaluated by measuring the glomerular filtration rate (GFR) using chromium ethylene diamine tetra-acetate clearance ((51)Cr-EDTA mL/min/ 1.73 m(2)) at baseline, 12, 24, and 36 months. 24-hour proteinuria was measured at baseline, 3, 6, 12, 18, 24, and 36 months of ERT. Kidney disease was classified according to National Kidney Foundation Disease Outcome Quality Initiative (NKF/DOQI) Advisory Board criteria, which define stage I chronic kidney disease (CKD) as GFR >or= 90 mL/min/1.73 m(2), stage II as 60-89 mL/min/1.73 m(2), stage III as 30-59 mL/min/1.73 m(2), stage IV as 15-29 mL/min/1.73 m(2), and stage V as < 15 mL/min/1.73 m(2). RESULTS: Six patients completed 36 months of therapy, 2 patients completed 18 months, and 1 patient completed 12 months. Mean patient age at baseline was 34.6 +/- 11.3 years. During the study period, kidney function remained stable in patients with stages I, II, or III CKD. One patient, who entered the study with stage IV CKD, progressed to end-stage chronic kidney disease, beginning hemodialysis after 7 months and receiving a kidney transplant after 12 months of ERT. Proteinuria also remained stable in the group of patients with pathologic proteinuria. The use of agalsidase alfa was well tolerated in 99.5% of the infusions administered. CONCLUSION: Over the course of 36 months of ERT, there was no change in kidney function and 24-hour proteinuria. This suggests that agalsidase alfa may slow or halt the progression of kidney disease when used before extensive kidney damage occurs. No significant side effects were observed with ERT during the course of the study.

Fabry disease in hemodialysis patients in southern Brazil: prevalence study and clinical report.

BACKGROUND: Fabry disease (FD) is a lysosomal storage disorder caused by a deficiency of alpha-Galactosidase A (alpha-Gal A). Fabry nephropathy typically progresses throughout the fifth decade to end-stage renal disease (ESRD), requiring hemodialysis and/or kidney transplantation. OBJECTIVE: To estimate the prevalence of FD among ESRD males on hemodialysis treatment in Rio Grande do Sul, the southernmost state of Brazil. METHODS: Screening for alpha-Gal A activity was performed by a dried blood spot (normal reference value: >1.5 nmoles/hour/mL). Positive screening results were confirmed by plasma alpha-Gal A activity assay (reference value: >3.3 nmoles/hour/mL). RESULTS: Five hundred fifty-eight male patients on hemodialysis were evaluated. Of these, only two had low alpha-Gal A activity and were diagnosed with Fabry disease (0.36%). One of these, age 42, had left ventricular hypertrophy and renal manifestations of Fabry disease without the classic symptoms. The other, age 46, had the classical manifestations of angiokeratomas, acroparesthesias, hypohidrosis, and ocular opacities. CONCLUSIONS: Although the prevalence of Fabry disease was very low in our study (0.36%), routine screening of male hemodialysis patients would enable earlier identification of many other affected relatives in their families who might benefit from specific clinical treatment.

Frequency and clinical profile of patients with polycystic kidney disease in southern Brazil.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic nephropathies, affecting one in every 800-1000 individuals in the worldwide general population and 5-10% of hemodialysis patients. Little data concerning the prevalence of ADPKD in Brazil are available. Thus, the aim of the present study was to investigate both the frequency and clinical profile of ADPKD among hemodialysis patients in south of Brazil. METHODS: This cross-sectional study consisted of patients from 24 hemodialysis centers. Patients were screened for ADPKD by clinical, laboratorial, and image examination in medical records. RESULTS: Of 1326 patients on hemodialysis in the south of Brazil that composed this study, 99 (7.5%) had polycystic kidney as primary cause for chronic renal failure. Comparisons between ADPKD and non-ADPKD patients revealed no differences regarding mean age, gender, and ethnicity. CONCLUSIONS: Our data revealed that ADPKD is prevalent among patients on hemodialysis in the south of Brazil. In addition, the clinical profile of ADPKD is similar to reported data from North America and Europe, putatively due to the similar ethnic composition mainly based on European descents.

Prevalence of 4977bp deletion in mitochondrial DNA from patients with chronic kidney disease receiving conservative treatment or hemodialysis in southern Brazil.

BACKGROUND: Damage to mitochondrial DNA (mtDNA) has been described in patients with chronic kidney disease (CKD). The presence of mtDNA 4977bp deletion in many different tissues can serve as a marker of this damage. However, no attempt has been made to detect the presence of mtDNA 4977bp in blood cells of patients with CKD. METHODS: Polymerase chain reaction techniques (PCR) were used to detect mtDNA 4977bp deletion in blood samples of 94 CKD patients. RESULTS: The prevalence of 4977bp deletion in mtDNA was 73.1% (38/52) in patients with CKD undergoing hemodialysis, 57.1% (27/42) in patients with CKD receiving conservative treatment, and 27.8% (15/54) in control samples (p < 0.001). Higher prevalence of this mutation was not associated with patient age (p = 0.54) or time on hemodialysis (p = 0.70). CONCLUSION: The higher prevalence of mtDNA 4977bp deletion in patients in this study indicates that the CKD can induce damage to mtDNA in blood cells and could be exacerbated by hemodialysis.

Influence of ACE I/D gene polymorphism in the progression of renal failure in autosomal dominant polycystic kidney disease: a meta-analysis.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is a renal disease characterized by an important variability in clinical course, which cannot be fully explained by the genetic heterogeneity of the disease. Although the role for the angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) polymorphism as a modifier factor in ADPKD renal deterioration has been suggested, direct evidence from genetic association studies remain inconclusive. To provide a more robust estimate of the putative effect of the ACE I/D polymorphism on the renal progression in ADPKD, we performed a meta-analysis pooling data from all relevant studies in which the role of the ACE I/D variant in ADPKD clinical features was evaluated. METHODS: We applied a random-effects model to combine odds ratio and 95% confidence intervals. Q-statistic was used to evaluate the homogeneity, and both Egger's and Begg-Mazumdar tests were used to assess publication bias. RESULTS: Altogether, three distinct meta-analyses were generated using data from 13 studies. Despite the absence of publication bias and the presence of homogeneity among study results, the DD genotype failed to show an influence on risk of end-stage renal disease (ESRD), mean age at ESRD or risk of hypertension in ADPKD patients when compared with I-allele carriers (DD vs ID+II). Likewise, meta-analyses carried out separately for Caucasian and Asian studies showed no indication of an association between the DD genotype and a faster renal deterioration in ADPKD. CONCLUSION: These findings do not support the hypothesis that the enhanced ACE activity associated with the D allele might promote a significantly worse prognosis in patients with ADPKD.

Danos moleculares em pacientes urêmicos submetidos à hemodiálise / Molecular damage in uremic patients on hemodialysis

Os efeitos tóxicos decorrentes do estado urêmico e do tratamento através de hemodiálise vêmsendo sugeridos como responsáveis por danos no DNA em pacientes com insuficiência renal crônica.Dessa forma, muitos trabalhos têm desenvolvido marcadores capazes de identificar esses danosatravés da análise cromossômica, teste de micronúcleos, teste do cometa, teste eletroquímico e,mais recentemente, análise do DNA mitocondrial. Considerando que esses danos podem aumentara incidência de câncer, mais estudos devem continuar sendo desenvolvidos nesse sentido.

The toxic effects caused by the uremic state and hemodialysis have been suggested asbeing responsible for DNA damage in patients with chronic renal failure. Thus, many researchershave developed markers capable of identifying these damages using chromosome analysis,micronucleus test, comet assay, electrochemical test and, more recently, mitochondrial DNA analysis.Further studies must be undertaken, since these damages can increase the incidence of cancer.

Genes envolvidos no controle do desenvolvimento inicial do rim / Genes involved in the control of early kidney development

As doenças renais humanas são uns dos maiores problemas de saúde, e vários genes quecontrolam a nefrogênese estão associados com essas doenças. Os principais genes envolvidosno desenvolvimento inicial do rim são PAX2, EYA1, SIX1 E 2, SALL1, FOXC1, WT1, HOX11, e amaioria dos fatores transcricionais desses genes é importante na regulação do gene GDNF. Essesgenes interagem uns com os outros, formando uma espécie de rede genética. O estudo dessasinterações genéticas é essencial para o entendimento das bases moleculares das malformaçõesdo desenvolvimento renal, que é necessário para a prevenção e tratamento dessas desordens.

Renal human diseases are among the leading health problems and many genes that controlnephrogenesis are associated with these diseases. The main genes involved in early kidneydevelopment are PAX2, EYA1, SIX1 and 2, SALL1, FOXC1, WT1, HOX11, and the majority oftheir transcriptional factors are relevant to the regulation of GDNF. Those genes interact with oneanother to create a genetic network. The study of such genetic interactions is crucial forunderstanding the molecular basis of kidney development malformations, which is necessary forthe prevention and treatment of these disorders.

Principais malformações congênitas macroscópicas do trato urinário superior / Major macroscopic congenital malformations of the upper urinary tract

Praticamente um terço de todas as malformações congênitas é encontrado no sistemaurogenital. A grande maioria das anormalidades do trato urinário tem pouco efeito no feto dentro doútero. Mesmo malformações letais para os neonatos não comprometem os fetos, uma vez que aplacenta e a mãe administram a função hidrostática renal. As principais malformações do tratourogenital são: agenesia renal, persistência de lobação fetal, fusão renal ou rim em ferradura,duplicação de ureter, obstrução ureteral ou ectopia dos ureteres, rim supranumerário e rim ectópico.Em termos de clínica médica, as ferramentas mais usadas na investigação das malformações dotrato urinário são os exames de imagem. A identificação desses distúrbios é importante para amanutenção dos pacientes. Esta revisão busca descrever as principais malformações renais,contribuindo para o desenvolvimento da nefrogenética.

Almost 1/3 of all congenital malformations are found in the urogenital tract. Most urinary tractabnormalities have little impact on fetus development. Even newborn lethal malformations do notrepresent a difficulty for the fetus, since the placenta and the mother manage the renal hydrostaticfunction. Major urogenital tract anomalies are renal agenesia, persistent fetal lobation, horseshoekidney, ureteral duplication, ureteral obstruction or ectopic ureter, supernumerary kidney and ectopickidney. Imaging examinations are the most common tools used in the clinical investigation of urinarytract malformations. The identification of these disorders is important for patient maintenance. Thisreview reports the major renal anomalies, thus contributing to the development of nephrogenetics.