Does asymmetric dimethylarginine (ADMA) plasma concentration predict esophageal varices in patients with cirrhosis?

BACKGROUND: In previous studies elevated Asymmetric NG, NG - dimethylarginine (ADMA) plasma levels, an endogenous nitric oxide synthase inhibitor, correlated with the severity of hepatic venous pressure gradient measurement, both in peripheral and in hepatic veins. The aim of this study was to explore whether elevated ADMA plasma levels were able to predict the presence of esophageal varices (EV) and/or large EV in patients with cirrhosis. METHODS: 74 cirrhotic patients who had undergone elective upper gastrointestinal endoscopy in order to assess the presence of portal hypertension and predictors of EV and/or large EV. ADMA levels were assayed by an ELISA test (Immundiagnostik AG, Germany). RESULTS: 53 patients had EV (26/53 had large EV). Univariate analysis of low hemoglobin (p = 0.045), PT-INR (p = 0.003), albumin (p = 0.024), bilirubin (p = 0.036), Child-Pugh score (p = 0.026), and ascites (p = 0.036) predicted the presence of EV. Multivariate analysis predicted EV for only PT-INR. The presence of large EV was predicted with univariate analysis of ADMA plasma levels (p = 0.013), low hemoglobin (p < 0.001), PT-INR (p = 0.001), albumin (p = 0.001), bilirubin (p = 0.026), Child-Pugh score (p < 0.001), ascites (p = 0.004). Sensitivity, specificity, predictive positive and negative values of ADMA plasma level > 0.5 micromol/L(-1) in predicting large EV were 0.69 (95% CI 0.53 - 0.82), 0.51 (95% CI 0.40 - 0.62), 0.43 (95% CI 0.31 - 0.56), 0.76 (95% CI 0.62 - 0.86), while the area under the ROC curve was 0.65 (95% CI 0.51 - 0.79). CONCLUSIONS: ADMA plasma levels were increased in cirrhotics with more advanced liver failure but did not prove to be a useful clinical tool for predicting the presence of esophageal varices or large esophageal varices.

Molecular characterization and sequence analysis of polyomavirus BKV-strain in a renal-allograft recipient.

The significance of polyomavirus (PV) infection was investigated in a 53-year-old patient who underwent renal transplantation and was treated with triple immunosuppressive therapy (tacrolimus, prednisone, and azathioprine). A renal biopsy taken because of the suspicion of acute rejection showed focal inflammatory interstitial infiltration, tubulitis, and tubular cell nuclear changes consistent with the hypothesis of viral infection. Both the tubular and decoy cells identified by means of urinalysis positively stained for anti-SV40 antibody. Polymerase chain reaction performed on the DNA extracted from renal tissue and isolated from urine showed the presence of an antigenic variant (AS) of the BKV archetype after sequence analysis of the transcription control region (TCR). On the basis of the diagnosis of BKV infection, immunosuppressive therapy was reduced. The patient's renal function improved and was still stable 8 months later when urinalysis showed only a few decoy cells, which were found to be infected by JC but not BK virus. These data suggest that only the BKV, probably favoured by immunosuppressive therapy (tacrolimus), causes renal damage. It is worth underlining that even small and sporadic viral genome mutations may lead to pathologic effects.

Molecular characterization and sequence analysis of polyomavirus strains isolated from needle biopsy specimens of kidney allograft recipients.

We retrospectively examined 29 renal allograft biopsy specimens from 42 kidney transplant recipients by means of molecular biologic techniques (nested polymerase chain reaction), immunohistochemical analysis (anti-SV40 antibody), and histologic examination to evaluate the presence of polyomaviruses (PVs), viral genotypes, genomic mutations, and their pathologic significance. PV genomes were found in six cases (21%); restriction fragment length polymorphism analysis characterized 4 as JC virus (JCV) and 2 as BK virus (BKV). The latter also were positively stained immunohistochemically and showed histologically typical intranuclear viral inclusions; JCV cases were negative. DNA sequence analysis revealed only minor changes in the 4 JCV cases (3 archetypes and 1 JCV type 3, not associated with a known pathogenic genotype) but identified 2 specific variants in the BKV isolates (AS and WW strains). Given the different histologic findings (mixed inflammatory infiltration in the AS and no inflammation in the WW strain), we speculate that different BKV strains may cause differential damage in transplanted kidneys. Finally, the negative histologic and immunohistochemical JCV results, as well as the absence of viral mutations, indicate that JCV renal infection is latent in transplant recipients.