Plasma endothelin-1 concentrations in children with cirrhosis and their relationship to renal function and the severity of portal hypertension

Biliary Atresia Is Associated With Hypertension

OBJECTIVES

The improved survival of pediatric liver transplant recipients is accompanied by an increase in long-term comorbidities. A recently highlighted concern, hypertension, is associated with chronic kidney disease (CKD) in this population and can result in other target-organ damage during childhood. The prevalence of hypertension in pediatric liver transplantation is imprecisely known. In addition, individual etiologies of liver failure may convey different risks of hypertension. We sought to study the effect of liver transplantation on the prevalence of hypertension and CKD in patients with biliary atresia (BA).

METHODS

We conducted a retrospective chart review of 160 patients with BA followed at the Mount Sinai Medical Center, New York, from 1987 to 2012. Data were accumulated from the initial and subsequent visits at approximately 6 months, 1, 3, 5, 10, and 15 years of age. Hypertension was defined as systolic blood pressure >95th percentile for age, sex, height, and/or use of antihypertensive medication. Renal function was examined over time. Data were stratified by liver transplantation status at the time of visit.

RESULTS

A high prevalence of hypertension was observed from the initial visit through age 10, independent of transplant status (transplanted: 48% initial visit and 13% after 10 years vs nontransplanted: 55% initial visit and 17% after 10 years [P = ns for transplant status]). Mean estimated glomerular filtration rate (eGFR) was lower among liver transplant patients as compared with nontransplant patients and declined posttransplant. The incidence of CKD was higher among transplant patients.

CONCLUSIONS

Hypertension is common among children with BA, independent of liver transplant status. Transplant patients had significantly reduced renal function, which continued to decline over time. Hypertension was not associated with reduced eGFR.

Bosentan treatment of portopulmonary hypertension related to liver cirrhosis owing to hepatitis C

Pulmonary arterial hypertension (PAH) with coexisting portal hypertension has been defined as portopulmonary hypertension (PPHTN). It is often related to liver cirrhosis of various aetiologies and is associated with a high mortality rate. Endothelin-1 (ET) is supposed to play an important role in the pathogenesis of PAH as well as portal hypertension. Therefore, therapy with an ET(A)/ET(B) receptor antagonist might be of use in the treatment of PPHTN. We report the case of a 76-year-old male with liver cirrhosis owing to chronic hepatitis C virus infection and PPHTN who was treated with the dual ET(A)/ET(B) receptor antagonist bosentan. The patient showed remarkable improvement of 6-min walking distance from 300 to 480 m after 2 weeks and to 540 m after 14 weeks, respectively. In addition, a significant decline of N-terminal pro B-type natriuretic peptide fraction (NT-proBNP) from 4928 ng mL(-1) to 640 ng mL(-1) was observed. Bosentan might be a promising new therapeutical option for patients suffering from PPHTN.

Pharmacokinetics and pharmacodynamics of the ETA-selective endothelin receptor antagonist SPP301 in healthy human subjects

SPP301 is a competitive antagonist of ET-1 with a high selectivity for the ETA receptor. A double-blind, placebo-controlled study was performed to investigate the tolerability, pharmacokinetics, and pharmacodynamics of SPP301 after single oral doses in male healthy subjects; doses of 5, 20, 50, 100, and 200 mg were given to different groups of 4 or 8 subjects each. The effect of food on the pharmacokinetics of SPP301 was assessed for the 50-mg dose according to a sequential design in the same subjects. At regular intervals, blood pressure and pulse rate, plasma levels of ET-1 and of SPP301 and its hydroxymethyl metabolite, and urinary excretion of the parent drug and its metabolite were determined. SPP301 was generally well tolerated. At doses >20 mg, adverse events that are typical for vasodilating agents-namely, headache, nausea and vomiting, dizziness, and postural hypotension-were observed. Maximum plasma levels of SPP301 were reached within 4.5 hours. Cmax and AUC values increased linearly with doses up to 100 mg. The apparent terminal half-life was quite constant over the whole dose range and ranged from 7.5 to 15.2 hours. Urinary excretion of SPP301 was below 0.1% of any dose. Cmax and AUC of the metabolite amounted only to about 5% of the values for SPP301. Concomitant food intake had no effect on the overall exposure but increased average peak plasma concentrations of SPP301 by around 50%. Plasma ET-1 increased nearly twofold at the 5-mg SPP301 dose, with no further relevant increase at higher doses. In conclusion, SPP301 is an active ET-1 antagonist and is well tolerated. The pharmacokinetics of the drug and its metabolite are linear up to 100 mg. Food does not affect overall exposure of SPP301 but increases Cmax. Urinary excretion of SPP301 is below 0.1% of the dose administered.