Gianfranco Lisi

Capillary electrophoresis in the evaluation of ischemic injury: simultaneous determination of purine compounds and glutathione.

An understanding of tissue energy metabolism and antioxidant status is of major interest in the field of organ preservation for transplantation. Nucleotide and glutathione are indicators of cell damage occurring during ischemia and reperfusion. A high performance capillary electrophoresis (HPCE) method with UV detection (185 nm) for the simultaneous analysis of intracellular free ribonucleotides, nucleosides, bases and glutathione (oxidized and reduced form) in myocardial tissues is described. The method does not involve thiol derivatization. The separations were carried out in an uncoated fused‐silica capillary, 60 cm long, 52.5 cm to detector, 75 μm ID, with 20 mM Na‐borate buffer, pH 10.00, at 20 kV voltage and reading at 185 nm. Injection was hydrostatic for 12 s and total analysis time was 20 min. The technique enables optimum separation of all the compounds examined and has a resolution similar to that of HPLC analysis, with the advantage of fast simultaneous measurement of cell nucleotide metabolism and redox state, not possible with HPLC.

Predictive role of pretransplant serum CXCL10 for cardiac acute rejection.

Background. The detection of acute rejection in heart transplantation remains an important feature of transplant management, especially in the early phase. Frequent surveillance with endomyocardial biopsy is necessary, even though it is an invasive procedure and carries a certain risk. Hence, noninvasive biomarkers able to predict acute rejection could be a further helpful tool in patient management. The interferon-&ggr;-inducible chemokine CXCL10 is required for initiation and development of graft failure caused by acute or chronic rejection. It has been reported that CXCL10 serum level is predictive of graft loss in kidney graft recipients. In the present study, we investigated whether pretransplant CXCL10 serum level may be a predictive noninvasive biomarker in heart transplant (HTx) recipients, as well. Methods. Sera from 143 patients undergoing orthotopic heart transplantation were collected before surgery and tested for CXCL10 and CCL22 and compared with serum samples from healthy subjects. Results. We found that basal CXCL10 serum levels in HTx recipients were significantly higher than in healthy subjects, whereas no difference was seen in CCL22 levels. Among HTx recipients, CXCL10 serum levels of rejectors were significantly higher than in nonrejectors. Our results showed that CXCL10 was a significant independent risk factor of several variables and had the highest predictive value for early acute heart rejection, with 160 pg/mL cutoff value. Conclusions. In HTx recipients, measurement of pretransplant CXCL10 serum levels could be a clinically useful tool for predicting cardiac acute rejection, especially in the early posttransplant period.

Endothelin receptors in adult human and swine isolated ventricular cardiomyocytes

The present study aimed to investigate endothelin-1 (ET-1) receptors in human and swine cardiomyocytes with binding studies using ET(A) and ET(B) selective receptor antagonists (BMS-182874 and BQ-788, respectively). Cell distribution of mRNA expression for ET(A) and ET(B) subtypes was investigated by in situ hybridization using specific cDNA probes. The 1251-ET-1 binding, which reached equilibrium in about 120 min (Kobs = 0.051+/-0.003 min(-1)), was only partially displaceable by the addition of a large excess of ET-1 (about 15% with a half-life of 20 min). In equilibrium binding studies, 125I-ET-1 had a Kd of 0.43+/-0.08 nM and a maximum binding (Bmax) of 42.8+/-6.6 fmol/mg protein. ET(A) and ET(B) receptors are represented in human and swine cardiomyocytes with an 85:15 ratio as indicated by the biphasic pattern of competition of both BMS-182874 and BQ-788. In situ hybridization studies confirmed that myocytes mainly expressed mRNA for ET(A), whereas expression of mRNA for the ET(B) subtype was documented in non-myocyte cells. These results showed that ET-1 binds with high affinity and poor reversibility to specific receptors, in both human and swine isolated ventricular cardiomyocytes, without significant species differences.

Reduction of oxidative stress does not affect recovery of myocardial function: warm continuous versus cold intermittent blood cardioplegia.

OBJECTIVE: To compare oxidative stress after cardiac surgery in patients treated with two different methods of myocardial protection: warm continuous versus cold intermittent blood cardioplegia. To correlate oxidative stress with postoperative myocardial dysfunction. DESIGN: Prospective, randomised, double blind, trial. SETTING: Institutional centre of cardiovascular surgery. PATIENTS: 20 patients were selected for coronary artery bypass surgery (CABG) on the following basis: stable angina, ejection fraction > 50%, double or triple vessel disease, no previous CABG or associated disease. Patients were randomised to two groups of 10 patients each. INTERVENTIONS: Patients underwent CABG with one of two different methods of myocardial protection and cardiopulmonary bypass. CBC group: intermittent cold blood antegrade-retrograde cardioplegia with moderate hypothermic cardiopulmonary bypass; WBC group: continuous warm blood antegrade-retrograde cardioplegia with mild hypothermic cardiopulmonary bypass. MAIN OUTCOME MEASURE: The index of oxidative stress used was the alteration of whole blood and plasma glutathione redox status. Samples were collected from the coronary sinus and peripheral vein before anaesthesia (T1), before aortic unclamping (T2), 15 minutes (T3), and 30 minutes (T4) after unclamping. Haemodynamic parameters were measured with thermodilution techniques. RESULTS: Oxidised glutathione and glutathione-cysteine mixed disulphide significantly increased in the coronary sinus plasma in the CBC group, and the overall redox balance of glutathione was decreased (P < 0.01) at T2-T4 versus T1, and compared with the WBC group. Comparable results were obtained for coronary sinus blood. There was no correlation between postoperative haemodynamic measurements and oxidative stress markers. CONCLUSIONS: Oxidative stress was significant in patients undergoing CABG using cold blood cardioplegia, while the warm technique minimised the effects of ischaemia. However, oxidative stress was not correlated with myocardial dysfunction following CABG.

Left ventricular twist in clinically stable heart transplantation recipients: A speckle tracking echocardiography study

BACKGROUND AND AIM Cavity twist is an integral part of LV function and its pattern in transplanted hearts is not well known. This study aimed at exploring LV twist in clinically stable heart transplant (HT) recipients with no evidence for rejection. METHODS We studied 32 HT patients (54 ± 24 months after HT), 34 other cardiac surgery (CS) patients and compared them with 35 health controls using speckle tracking echocardiography, measuring peak twist angle, time-to-peak twist, and untwist rate. RESULTS LV twist angle was smaller in the HT group (6.2 ± 3.3°) in comparison with the CS group and controls (13.2 ± 3.5° and 13.1 ± 4.5°, respectively; p<0.0001 for all) and untwist rate was reduced (HT group: -74 ± 30°/s; CS group: -118 ± 43°/s; controls: -116 ± 39°/s; p<0.0001 for all). Time-to-peak twist was not different between groups. Time after HT was the main independent predictor of both LV twist angle and untwist rate (β=0.8, p<0.0001). CONCLUSION Though clinically stable, LV twist dynamics are significantly impaired in HT recipients, even in comparison with patients who underwent other cardiac surgery.

Mitral regurgitation severity correlates with symptoms and extent of left atrial dysfunction: Effect of mitral valve repair

We aimed to assess the relationship between mitral regurgitation (MR) severity, symptoms, and left atrial (LA) structure and function, before and after mitral valve repair (MVR).

Total arterial myocardial revascularization without cardiopulmonary bypass

The risks associated with cardiopulmonary bypass have led to an interest in coronary surgery without the use of such a bypass. Six patients of mean(s.d.) age 62.0(8.0) (range 52-71) years were selected for elective coronary surgery without cardiopulmonary bypass. In five cases a midline sternotomy and in one case a small anterolateral thoracotomy were performed; in the latter case the harvesting of the proximal end of the left internal mammary artery was video-assisted by thoracoscopy. The left internal mammary artery was used in all cases; the right internal mammary artery was used in one case, the radial artery in four, the inferior epigastric artery in two and the right gastroepiploic artery inn one. No patient died or had a stroke. There were no postoperative episodes of low cardiac output syndrome or perioperative myocardial infarction. All patients were extubated within a few hours after surgery. The mean(s.d.) intensive care unit and hospital stays were 1.3(0.5) and 5.0(0.9) days, respectively. Total arterial myocardial revascularization without cardiopulmonary bypass using composite grafts, is a new and promising technique that is feasible with low risks and good early results in selected cases.