Urinary DPP4 correlates with renal dysfunction, and DPP4 inhibition protects against the reduction in megalin and podocin expression in experimental CKD

This study investigated the molecular mechanisms underlying the antiproteinuric effect of DPP4 inhibition in 5/6 renal ablation rats and tested the hypothesis that the urinary activity of DPP4 correlates with chronic kidney disease (CKD) progression. Experiments were conducted in male Wistar rats who underwent 5/6 nephrectomy (Nx) or sham operation followed by 8 wk of treatment with the DPP4 inhibitor (DPP4i) sitagliptin or vehicle. Proteinuria increased progressively in Nx rats throughout the observation period. This increase was remarkably mitigated by sitagliptin. Higher levels of proteinuria in Nx rats compared to control rats were accompanied by higher urinary excretion of retinol-binding protein 4, a marker of tubular proteinuria, as well as higher urinary levels of podocin, a marker of glomerular proteinuria. Retinol-binding protein 4 and podocin were not detected in the urine of Nx + DPP4i rats. Tubular and glomerular proteinuria was associated with the reduced expression of megalin and podocin in the renal cortex of Nx rats. Sitagliptin treatment partially prevented this decrease. Besides, the angiotensin II renal content was significantly reduced in the Nx rats that received sitagliptin compared to vehicle-treated Nx rats. Interestingly, both urinary DPP4 activity and abundance increased progressively in Nx rats. Additionally, urinary DPP4 activity correlated positively with serum creatinine levels, proteinuria, and blood pressure. Collectively, these results suggest that DPP4 inhibition ameliorated both tubular and glomerular proteinuria and prevented the reduction of megalin and podocin expression in CKD rats. Furthermore, these findings suggest that urinary DPP4 activity may serve as a biomarker of renal disease and progression.

[Imerslund-Gräsbeck syndrome: report of two cases]

INTRODUCTION: The Imerslund-Gräsbeck syndrome is a rare hereditary autosomal recessive disease, characterized by the onset of megaloblastic anemia and asymptomatic proteinuria during the first 2 years of life. OBJECTIVE: To emphasize the importance of early detection of this disorder, due to high morbidity when not correctly treated, in addition to the necessity of screening and genetic counseling of the asymptomatic family members. METHODS: The authors report two patients, male and female, 8 and 10 years old, respectively. Their past history revealed anemia and multiple blood transfusions since their infancy. They evolved with pancytopenia during childhood and diagnosis of Severe Aplastic Anemia or Fanconi Syndrome was suspected. They were referred to the Bone Marrow Transplantation Section -HC- UFPR. RESULTS: Laboratory investigations revealed pancytopenia in peripheral blood. Bone marrow aspiration showed a marked megaloblastic erythropoiesis. Twenty-four-hour urine collection revealed proteinuria (3.0 and 5.8 g/dl respectively). Cytogenetic analysis was normal. Resolution of symptoms followed replacement therapy with parenteral vitamin B12. CONCLUSIONS: The presence of megaloblastic anemia in children should be followed by investigation of proteinuria, due to the existence of this rare disorder, that has a simple diagnosis and an effective treatment.

[A myoelectric prosthesis for the forearm amputee]

The authors make a revision of the principles of action of the myoelectric prosthesis for the forearm amputees and describe their components. The indications and contra-indications (French law) are also referred. We can say as a conclusion that the great progress made in prosthesis in the last years were possible on account of synthetic materials and the use of electronics and miniaturised computers. However, their functional possibilities are remote when compared with the human hand. The high costs of this prosthesis are one limitation to its prescription.