Urinary exosomes and diabetic nephropathy: a proteomic approach

Urinary exosomes (UE) are nanovesicles released by every epithelial cell facing the urinary space and they are considered a promising source of molecular markers for renal dysfunction and structural injury. Exosomal proteomics has emerged as a powerful tool for understanding the molecular composition of exosomes and has potential to accelerate biomarker discovery. We employed this strategy in the study of diabetic nephropathy (DN) and the consequent end stage renal disease, which represent the dramatic evolution of diabetes, often leading the patients to dialysis or kidney transplantation. The identification of DN biomarkers is likely to help monitoring the disease onset and progression. A label free LC-MS/MS approach was applied to investigate the alteration of the proteome of urinary exosomes isolated from the Zucker diabetic fatty rats (ZDF), as a model of type 2 DN. We collected 24 hour urine samples from 7 ZDF and from 7 control rats at different ages (6, 12 and 20 weeks old) to monitor the development of DN. Exosomes were isolated by ultracentrifugation and their purity assessed by immunoblotting for known exosomal markers. Exosomal proteins from urine samples of 20 week old rats were pooled and analyzed by nLC-ESI-UHR-QToF-MS/MS after pre-filtration and tryptic digestion, leading to the identification and label free quantification of 286 proteins. Subcellular localization and molecular functions were assigned to each protein by UniprotKB, showing that the majority of identified proteins were membrane-associated or cytoplasmic and involved in transport, signalling and cellular adhesion, typical functions of exosomal proteins. We further validated label free mass spectrometry results by immunoblotting, as exemplified by: Xaa-Pro dipeptidase, Major Urinary Protein 1 and Neprilysin, which resulted increased, decreased and not different, respectively, in exosomes isolated from diabetic urine samples compared to controls, by both techniques. In conclusion we show the potential of exosome proteomics for DN biomarker discovery.

Use of the BasGan algorithm for [123I]FP-CIT SPECT quantification: a phantom study

AIM

The BasGan algorithm has been specifically developed for semi-automatic quantification of [123I]FP-CIT SPECT studies. The aim of this work was to evaluate the software linearity and its dependence on the main acquisition parameters of the SPECT study.

METHODS

The anthropomorphic Striatal Phantom filled with different striatal to background activity concentration ratios was used to verify software linearity. The software response was studied with different acquisition parameters and system configurations. For this purpose, phantom studies were performed with varying radius of rotation, pixel size, number of projections and with different collimator types. For each configuration the tomographic spatial resolution was also determined using the Triple Line Source Phantom. The reconstructed SPECT images were corrected for attenuation and scatter.

RESULTS

The BasGan outcome highly correlates with the real Specific Binding Ratio when fixed gamma camera configuration and reconstruction method are used. However, the software quantification depends on system configuration and decreases with increasing partial volume effect. A comparison of the BasGan output with tomographic spatial resolution data for each configuration shows that the software response highly correlates with this quantity.

CONCLUSION

The BasGan algorithm is a free, easy-to-use and solid tool for quantification of [123I]FP-CIT images. The software outcome depends on system configuration, but highly correlates with tomographic spatial resolution. Then, the measurement of this quantity turns out to be a simple method to normalize the BasGan quantification for different imaging devices, making it possible the use of available reference values for normal subjects and multicentre studies.

Effects of N,N-dimethylglycine sodium salt on apparent digestibility, vitamin E absorption, and serum proteins in broiler chickens fed a high- or low-fat diet

The objective of this study was to assess the effect of supplementation with sodium salt of N,N-dimethylglycine (DMG-Na) on apparent digestibility (AD) in broiler chickens fed low- and high-fat diets. Twenty-eight 1-d-old broiler chickens were fed one of the dietary treatments: a low-fat diet (LF) or a high-fat diet (HF) supplemented with or without 1,000 mg/kg of DMG-Na. Body weight and feed consumption were recorded at 14 and 35 d of age. Average daily growth, daily feed intake, and feed conversion ratio were calculated. The AD of DM, organic matter (OM), CP, total fat (TF), and α-tocopheryl-acetate were assessed by 2 digestibility trials (at 18-21 and 32-35 d, respectively). Serum protein and plasma α-tocopherol concentrations were assessed at 35 d of age. Final BW, feed intake, carcass, breast, and spleen weight were higher in groups fed LF than HF diets (P = 0.048, P = 0.002, P = 0.039, P < 0.001, P = 0.007, respectively). Liver weight was increased in DMG-Na-unsupplemented groups (P = 0.011) for both fat levels. During the first digestibility trial (18-21 d), the AD of DM (P = 0.023), OM (P = 0.033), CP (P = 0.030), and α-tocopheryl-acetate (P = 0.036) was higher in the DMG-Na-supplemented group than control. Digestibility of total fat was increased by DMG-Na supplementation in the LF groups (P = 0.038). A trend for improvement of digestibility was observed during the second digestibility trial (32-35 d) for DM (P = 0.089), OM (P = 0.051), and CP (P = 0.063) in DMG-Na groups. Total serum proteins (and relative fractions) were positively influenced by DMG-Na supplementation both in LF and HF diets (P = 0.029). Plasma α-tocopherol concentration was higher in groups fed LF than HF diets (P < 0.001).

[A model of intervention on company canteens to promote healthy diet]

The Workplace Health Promotion project, operating in the precinct of the Local Health Authority of Bergamo, contemplates that the partaking Companies should develop specific activities ("good practices") in the thematic area of proper nutrition. Six best practices have been defined on the basis of: contextual data, actions deemed most effective by the scientific publications, the "Guidelines for a healthy diet for the Italian, population" released by the Italian National Research Institute for Food and Nutrition the "Directions for healthy snacks for adults" elaborated by the Italian Association of Dietetics and Clinical Nutrition, and the national project "Gaining Health". Twenty-six Companies have chosen to implement good practices in the area of proper nutrition. The results of the undertaken actions have been measured at the first Company which participated in this program, and have been obtained through the administration of a pre- and postintervention questionnaire. The collected data show the efficacy of the proposed practices in modifying some incorrect dietary habits.