M. Giubbolini

Comparative determination of purine compounds in carotid plaque by capillary zone electrophoresis and high-performance liquid chromatography

Allantoin, uric acid (UA), hypoxanthine (Hx) and xanthine (X) were determined on carotid plaque by capillary zone electrophoresis (CZE) and high-performance liquid chromatography (HPLC). Comparison of the results showed that capillary zone electrophoresis may have similar or even superior analytical performance to HPLC, especially for the determination of allantoin in biological samples.

Proteomic analysis of atherosclerotic plaque.

Proteins play a fundamental role in the formation and progression of plaque, but proteomic analysis of plaque as a whole is difficult, due to its heterogeneous cellular composition and an abundance of plasma proteins. Several approaches to this problem are reported in the literature; they include proteomic analysis of vascular tissues, analysis of proteins released by normal and pathological arterial walls, proteomic analysis of vascular cells and proteomic analysis of blood. In a previous study, we proposed a new strategy for studying of proteome of plaque, which permits to select the proteins exclusive to plaque by the constructing of a reference synthetic gel. In the present work, we matched the spots of the reference synthetic gel with the spots of a pool of carotid plaque, in order to select only spots exclusive to plaque from the 2-dimensional electrophoresis of the pool of plaque. We selected some spots between those exclusive and identified them by mass spectrometry. Some proteins identified are involved in transport, others take part in elimination of toxic radicals, others are metabolic enzymes or structural proteins. This study represents an example of application of the new approach which we have proposed: the reference gel of proteome of plaque permits to select, on every sample of interest, only the spots exclusive to plaque; once selected, spots can be identified by mass spectrometry and, being typical of plaque composition, could represent novel markers of lesions and vascular risk.

Purine Catabolism in Advanced Carotid Artery Plaque

This study was carried out on carotid artery plaque and plasma of 50 patients. We analyzed uric acid, hypoxanthine, xanthine, and allantoin levels to verify if enzymatic purine degradation occurs in advanced carotid plaque; we also determined free radicals and sulphydryl groups to check if there is a correlation between oxidant status and purine catabolism. Comparing plaque and plasma we found higher levels of free radicals, hypoxanthine, xanthine, and a decrease of some oxidant protectors, such as sulphydryl groups and uric acid, in plaque. We also observed a very important phenomenon in plaque, the presence of allantoin due to chemical oxidation of uric acid, since humans do not have the enzyme uricase. The hypothetical elevated activity of xanthine oxidase in atherosclerosis could be reduced by specific therapies using its inhibitors, such as oxypurinol or allopurinol.

Fistula first, graft on arterialized vein second:

Objectives Arterovenous grafts (AVGs) present a feasible solution for creating a vascular access in patients who are unsuitable for autogenous fistula (AVF). The aim of this study is to assess the prevention rate of vein stenosis, placing a graft on an arterialized vein (GAV) instead of an anastomized AVG in a native vein (GNV). Methods This was a cohort study conducted from January 2009 to November 2012. All consecutive patients who underwent AVG in our institution were included. All patients requiring a secondary intervention were also referred to our centre. Patients underwent ultrasound follow up at first and the every month. A Kaplan–Meier method was used; a Log-rank test was used to identify whether significant difference existed between GAV and GNV (p < 0.05). Results Forty-six grafts were placed. Twenty patients had arterialized receiving veins (group A), while 26 patients received an AVG immediately because they lacked autogenous veins suitable for fistula (group B).The average follow-up period was 16.1 months (range 0–41). The group A 41 months-patency rate was 84.3%, while group B was 43.7% (p = 0.06). Secondary patency was similar in the two groups. Conclusions Vein arterialization seems to prevent venous stenosis improving AVG-patency rate. More data are needed; however, the borderline p value encourages new studies.