Serum Gamma-Glutamyltransferase Levels Predict Clinical Outcomes in Hemodialysis Patients

Elevated liver enzymes and cardiovascular mortality: a systematic review and dose-response meta-analysis of more than one million participants

Gamma glutamyl transferase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) are commonly used liver function markers. We performed a dose-response meta-analysis to investigate the association between liver enzymes and cardiovascular disease (CVD) mortality in prospective cohort studies. We conducted a systematic search up to April 2018 in Medline/PubMed, Scopus, Cochrane, and Embase databases. Combined hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using a random-effects model as described by DerSimonian and Laird. Dose-response analysis was also carried out. Twenty-three studies with 1 067 922 participants reported association between GGT and CVD mortality and were included in our analysis. Pooled results showed a significant association between GGT and risk of CVD mortality (HR: 1.62; 95% CI: 1.47-1.78, P=0.001, P-heterogeneity=0.001) and it was HR: 0.87; 95% CI: 0.73-1.07; P=0.221, P-heterogeneity=0.028, for ALT. There was a direct association between baseline levels of ALP and AST/ALT ratio with CVD mortality (HR: 1.45; 95% CI: 1.11-1.89; P=0.005, P-heterogeneity=0.026, and HR: 2.20; 95% CI: 1.60-3.04; P=0.001, P-heterogeneity=0.540, respectively). Pooled results did not show any significant association between AST and the risk of CVD mortality (HR: 1.20; 95% CI: 0.83-1.73; P=0.313, P-heterogeneity=0.024). Moreover, there was a significant nonlinear association between GGT and ALP levels and the risk of CVD mortality (P=0.008 and 0.016, respectively). Our dose-response meta-analysis revealed a direct relationship between GGT and ALP levels and the risk of CVD mortality. High levels of GGT, ALP and AST/ALT were associated with an increased CVD mortality rate.

Oxidative stress in hemodialysis: Causative mechanisms, clinical implications, and possible therapeutic interventions

Oxidative stress (OS) is the result of prooxidant molecules overwhelming the antioxidant defense mechanisms. Hemodialysis (HD) constitutes a state of elevated inflammation and OS, due to loss of antioxidants during dialysis and activation of white blood cells triggering production of reactive oxygen species. Dialysis vintage, dialysis methods, and type and condition of vascular access, biocompatibility of dialyzer membrane and dialysate, iron administration, and anemia all can play a role in aggravating OS, which in turn has been associated with increased morbidity and mortality. Oral or intravenous administration of antioxidants may detoxify the oxidative molecules and at least in part repair OS-mediated tissue damage. Lifestyle interventions and optimization of a highly biocompatible HD procedure might ameliorate OS development in dialysis.

norUrsodeoxycholic acid improves cholestasis in primary sclerosing cholangitis

BACKGROUND & AIM

Primary sclerosing cholangitis (PSC) represents a devastating bile duct disease, currently lacking effective medical therapy. 24-norursodeoxycholic acid (norUDCA) is a side chain-shortened C₂₃ homologue of UDCA and has shown potent anti-cholestatic, anti-inflammatory and anti-fibrotic properties in a preclinical PSC mouse model. A randomized controlled trial, including 38 centers from 12 European countries, evaluated the safety and efficacy of three doses of oral norUDCA (500mg/d, 1,000mg/d or 1,500mg/d) compared with placebo in patients with PSC.

METHODS

One hundred sixty-one PSC patients without concomitant UDCA therapy and with elevated serum alkaline phosphatase (ALP) levels were randomized for a 12-week treatment followed by a 4-week follow-up. The primary efficacy endpoint was the mean relative change in ALP levels between baseline and end of treatment visit.

RESULTS

norUDCA reduced ALP levels by -12.3%, -17.3%, and -26.0% in the 500, 1,000, and 1,500mg/d groups (p=0.029, p=0.003, and p<0.0001 when compared to placebo), respectively, while a +1.2% increase was observed in the placebo group. Similar dose-dependent results were found for secondary endpoints, such as ALT, AST, γ-GT, or the rate of patients achieving ALP levels <1.5× ULN. Serious adverse events occurred in seven patients in the 500mg/d, five patients in the 1,000mg/d, two patients in the 1500mg/d group, and three in the placebo group. There was no difference in reported pruritus between treatment and placebo groups.

CONCLUSIONS

norUDCA significantly reduced ALP values dose-dependently in all treatment arms. The safety profile of norUDCA was excellent and comparable to placebo. Consequently, these results justify a phase III trial of norUDCA in PSC patients. Lay summary: Effective medical therapy for primary sclerosing cholangitis (PSC) is urgently needed. In this phase II clinical study in PSC patients, a side chain-shortened derivative of ursodeoxycholic acid, norursodeoxycholic acid (norUDCA), significantly reduced serum alkaline phosphatase levels in a dose-dependent manner during a 12-week treatment. Importantly, norUDCA showed a favorable safety profile, which was similar to placebo. The use of norUDCA in PSC patients is promising and will be further evaluated in a phase III clinical study. ClinicalTrials.gov number: NCT01755507.