p-Cresol and Cardiovascular Risk in Kidney Transplant Recipients.

p-Cresol Sulphate (pCS) is a uremic toxin that originates exclusively from dietary sources and has a high plasma level related to chronic kidney disease (CKD) and cardiovascular disease (CVD). The aim of our study was to evaluate the plasma levels of pCS in kidney transplant recipients (KTRs) related to estimated glomerular filtration rate (eGFR), traditional risk factors, cardiovascular clinical events and endothelial progenitor cells (EPCs), bone marrow-derived cells for the vascular repair system. We considered 51 KTRs and 25 healthy blood donors (HBDs). pCs levels were analyzed using high-performance liquid chromatography (HPLC) coupled with mass spectrometry with an electrospray ionization (ESI) (LC/ESI-MS/MS) on a triple-quadrupole; EPCs were analyzed using flow cytometric analysis. eGFR was 52.61 ± 19.9 mL/min/1.73 m(2) in KTRs versus 94 ± 21 mL/min/1.73 m(2) in HBDs. We did not find differences in pCS levels between KTRs and HBDs. Levels of pCS were inversely related with eGFR in KTRs and pCS levels were significantly lower in KTRs with eGFR <30 mL/min/1.73 m(2) versus eGFR >30 mL/min/1.73 m(2). Furthermore, there was a difference in pCS levels between eGFR <30 mL/min/1.73 m(2) of KTRs compared with HBDs. Levels of pCS were almost significantly influenced by the presence of a previous vascular event and were inversely related with mature EPCs. These findings suggest that KTRs should not have higher CVD risk than HBDs and their physiological vascular repair system appears to be intact. In KTRs the reduction of eGFR also increased pCS levels and reduced EPCs numbers and angiogenesis capacity. In summary, pCS acts as an emerging marker of a uremic state, helping assess the global vascular competence in KTRs.

New horizon in dialysis depuration: Characterization of a polysulfone membrane able to break the 'albumin wall'.

The uremic syndrome is attributed to the progressive retention of a large number of toxins, which under normal conditions are excreted by the healthy kidneys. Standard dialytic membranes do not purify middle-high molecular weight toxins. Haemodiafiltration with endogenous reinfusion coupled with a highly permeable membrane could break the limit of the 'albumin wall' improving the dialytic depuration without loss of important nutrients. The aim of this study was to evaluate the performance of a new polysulfone membrane, Synclear 0.2, to remove uremic molecules. Surface Enhanced Laser Desorption Ionization-Time of Flight was employed to evaluate the proteomic profile of ultrafiltrate and Electrospray Ionization-Quadruple-ToF coupled with on-chip elution was used for proteins identification. A high and specific permeability for middle-high molecular weight molecules was revealed by mass spectrometry for the investigated membrane. The identified proteins are mostly uremic toxins: their relative abundance, estimated in the ultrafiltrate by exponentially modified protein abundance index, showed a high purification efficiency of the new membrane when compared with conventional ones. In conclusion, Synclear 0.2, used as convective membrane in hemodiafiltration with endogenous reinfusion treatment, permits to break the 'albumin wall', clearing middle-high molecular weight uremic toxins, improving the dialytic treatment purification efficiency.

The effect of chronic kidney disease on the urine proteome in the domestic cat (Felis catus).

Chronic kidney disease (CKD) is a major cause of mortality in cats, but sensitive and specific biomarkers for early prediction and monitoring of CKD are currently lacking. The present study aimed to apply proteomic techniques to map the urine proteome of the healthy cat and compare it with the proteome of cats with CKD. Urine samples were collected by cystocentesis from 23 healthy young cats and 17 cats with CKD. One-dimensional sodium-dodecyl-sulfate polyacrylamide gel electrophoresis (1D-SDS-PAGE) was conducted on 4-12% gels. Two-dimensional electrophoresis (2DE) was applied to pooled urine samples from healthy cats (n = 4) and cats with CKD (n = 4), respectively. Sixteen protein bands and 36 spots were cut, trypsin-digested and identified by mass spectrometry. 1D-SDS-PAGE yielded an overall view of the protein profile and the separation of 32 ± 6 protein bands in the urine of healthy cats, while CKD cats showed significantly fewer bands (P < 0.01). 2-DE was essential in fractionation of the complex urine proteome, producing a reference map that included 20 proteins. Cauxin was the most abundant protein in urine of healthy cats. Several protease inhibitors and transport proteins that derive from plasma were also identified, including alpha-2-macroglobulin, albumin, transferrin, haemopexin and haptoglobin. There was differential expression of 27 spots between healthy and CKD samples (P < 0.05) and 13 proteins were unambiguously identified. In particular, increased expression of retinol-binding protein, cystatin M and apolipoprotein-H associated with decreased expression of uromodulin and cauxin confirmed tubular damage in CKD cats suggesting that these proteins are candidate biomarkers.

Immunoglobulin gene mutations and frequent use of VH1-69 and VH4-34 segments in hepatitis C virus-positive and hepatitis C virus-negative nodal marginal zone B-cell lymphoma.

Nodal marginal zone B-cell lymphoma (NMZL) is actually considered as a distinct entity that must be distinguished from extra-nodal and splenic marginal zone lymphomas. To define the cell origin and the role of antigen stimulation we determined the nucleotide sequence of the tumor-related immunoglobulin heavy chain variable genes in 10 cases of NMZL. The results were also evaluated on the basis of the presence of chronic hepatitis C virus (HCV) infection. All 10 cases harbored VH somatic mutations with a sequence homology compared to the closest germline gene, ranging from 83.33 to 98.28%. Interestingly, different VH segments were preferentially used in HCV-positive and HCV-negative patients: three of five HCV-negative NMZLs used a VH4-34 segment joined with different D and JH segments whereas three of five HCV-positive NMZLs used a VH1-69 gene joined with a D3-22 and a JH4 segment, with very strong similarities in the CDR3s among the three different cases. These data indicate: 1) NMZL is derived from B cells that have experienced the germinal center reaction; 2) the preferential usage of a VH1-69 segment in the majority of the HCV-positive NMZL cases with similar CDR3s suggests the presence of a common antigen, probably a HCV antigen epitope, involved in the B-cell selection; and 3) the use of a VH4-34 segment suggests a role of yet unknown B-cell superantigen(s) in the selection of tumor B-cell precursors in HCV-negative NMZL.