The effects of immunosuppressive agents on the function of human hepatocytes in vitro

How important is donor age in liver transplantation?

The age of liver donors has been increasing in the past several years because of a donor shortage. In the United States, 33% of donors are age 50 years or older, as are more than 50% in some European countries. The impact of donor age on liver transplantation (LT) has been analyzed in several studies with contradictory conclusions. Nevertheless, recent analyses of the largest databases demonstrate that having an older donor is a risk factor for graft failure. Donor age is included as a risk factor in the more relevant graft survival scores, such as the Donor Risk Index, donor age and Model for End-stage Liver Disease, Survival Outcomes Following Liver Transplantation, and the Balance of Risk. The use of old donors is related to an increased rate of biliary complications and hepatitis C virus-related graft failure. Although liver function does not seem to be significantly affected by age, the incidence of several liver diseases increases with age, and the capacity of the liver to manage or overcome liver diseases or external injuries decreases. In this paper, the importance of age in LT outcomes, the role of donor age as a risk factor, and the influence of aging on liver regeneration are reviewed.

Mycophenolic acid affects basic functions of human keratinocytes in the IMPDH-dependent manner

Clinical studies suggest that the immunosuppressant MPA is associated with impaired wound healing. It is believed that the main cause of impairment is the inhibition of inflammatory response. However, it is unknown whether MPA may directly affect epidermal cells. The aim of our study was to examine the direct influence of mycophenolic acid, the selective blocker of de novo purine synthesis, on human epidermal keratinocyte morphology, proliferation, motile activity, and differentiation in in vitro culture. The number of keratinocytes cultured in the presence of MPA was counted and cell motility was measured by a time-lapse computer-aided method. Cell morphology was determined by flow and image cytometry methods. Real-time RT-PCR analysis was employed to investigate the expression of markers of differentiation. We showed that MPA induces irreversible inhibition of cell proliferation, causes cell enlargement and impairs cell locomotion in a time-dependent manner. The level of expression of differentiation markers was significantly reduced by MPA treatment. All these effects were reversed by the addition of guanine. Our results indicated that MPA impairs basic functions of human skin keratinocytes via intracellular guanosine nucleotide depletion, which may be directly reflected in wound healing problems in patients treated with this immunosuppressant.

Acute liver toxicity due to methylprednisolone: consider this diagnosis in the context of autoimmunity

The occurrence of corticosteroid-induced hepatitis is a rare event that has been recently described in the literature. We report the case of an acute cytolytic hepatitis in a patient treated with methylprednisolone for multiple sclerosis associated with an autoimmune thyroid dysfunction. After ruling out other etiologies, we concluded that the acute liver injury was due to steroids, and we analyzed the specific circumstances in the literature where methylprednisolone may have been responsible for acute hepatitis.

Mechanisms behind local immunosuppression using inhaled tacrolimus in preclinical models of lung transplantation

Inhaled immunosuppression with tacrolimus (TAC) is a novel strategy after lung transplantation. Here we investigate the feasibility of tacrolimus delivery via aerosol, assess its immunosuppressive efficacy, reveal possible mechanisms of action, and evaluate its airway toxicity. Rats received 4 mg/kg TAC via oral or inhaled (AER) administration. Pharmacokinetic properties were compared, and in vivo airway toxicity was assessed. Full-thickness human airway epithelium (AE) was grown in vitro at an air-liquid interface. Equal TAC doses (10-1,000 ng) were either added to the bottom chamber (MED) or aerosolized for gas-phase exposure (AER). Airway epithelium TAC absorption, cell toxicity, and interactions of TAC with NFκB activation were studied. Single-photon emission computed tomography demonstrated a linear tracer accumulation within the lungs during TAC inhalation. The AER TAC generated higher lung-tissue concentrations, but blood concentrations that were 11 times lower. Airway histology and gene expression did not reveal drug toxicity after 3 weeks of treatment. In vitro AE exposed to TAC at 10-1,000 ng, orally or AER, maintained its pseudostratified morphology, did not show cell toxicity, and maintained its epithelial integrity, with tight junction formation. The TAC AER-treated AE absorbed the drug from the apical surface and generated lower-chamber TAC concentrations sufficient to suppress activated lymphocytes. Tacrolimus AER was superior to TAC MED at preventing AE IFN-γ, IL-10, IL-13, monocyte chemoattractant protein-1 chemokine (C-C motif) ligand 5 (RANTES) and TNF-α up-regulation. Tacrolimus inhibited airway epithelial cell NFκB activation. In conclusion, TAC can be delivered easily and effectively into the lungs without causing airway toxicity, decreases inflammatory AE cytokine production, and inhibits NFκB activation.

The impact on biochemical profiles and allograft function for patients converted from cyclosporine to tacrolimus after clinical heart transplantation

OBJECTIVE

Tacrolimus, a potent calcineurin inhibitor, is a widely used immunosuppressant. This study sought to determine whether conversion from cyclosporine to tacrolimus afforded benefits on biochemical profiles and graft function among Chinese heart transplantation recipients.

METHODS

Forty-nine patients (44 men and 5 women) among 252 heart transplantations performed from 1995 to 2005 were converted from cyclosporine to tacrolimus due to rejection (69%) or to cyclosporine intolerance (31%). The median age of these recipients at transplantation was 46.4 years (range, 5 months to 68 years). Their median body weight was 60 kg (range, 4-84 kg). The allograft median ischemic time was 145 minutes (range, 52-300 minutes). We compared the biochemical markers, rejection episodes and allograft function.

RESULTS

The mean duration from heart transplantation to conversion was 419 days. After conversion, the serum bilirubin and alanine transaminase levels were significantly improved at 1 year. The lipid profiles, including triglycerides, total cholesterol, and low-density lipoprotein were nonsignificantly changed. The rejection episodes significantly decreased from 1.53 to 0.15 per patient per year (P < .001). The left ventricular ejection fraction significantly improved from 54.3 +/- 17.9% to 63.2 +/- 10.9% (P < .01). The right atrial pressure significantly decreased from 9.1 +/- 5.8 mmHg to 6.3 +/- 4.3 mm Hg (P < .01). The pulmonary capillary wedge pressure significantly decreased from 15.3 +/- 9.5 mm Hg to 10.8 +/- 5.3 mm Hg (P = .04).

CONCLUSION

In heart transplantation, conversion to tacrolimus owing to rejection or cyclosporine intolerance showed better liver profiles with fewer rejection episodes and improved graft function.

Liver cell transplantation for Crigler-Najjar syndrome type I: Update and perspectives

Liver cell transplantation is an attractive technique to treat liver-based inborn errors of metabolism. The feasibility and efficacy of the procedure has been demonstrated, leading to medium term partial metabolic control of various diseases. Crigler-Najjar is the paradigm of such diseases in that the host liver is lacking one function with an otherwise normal parenchyma. The patient is at permanent risk for irreversible brain damage. The goal of liver cell transplantation is to reduce serum bilirubin levels within safe limits and to alleviate phototherapy requirements to improve quality of life. Preliminary data on Gunn rats, the rodent model of the disease, were encouraging and have led to successful clinical trials. Herein we report on two additional patients and describe the current limits of the technique in terms of durability of the response as compared to alternative therapeutic procedures. We discuss the future developments of the technique and new emerging perspectives.