Effects of methylprednisolone on inflammatory activity and oxidative stress in the lungs of brain-dead rats

OBJECTIVE:

To evaluate the effects that early and late systemic administration of methylprednisolone have on lungs in a rat model of brain death.

METHODS:

Twenty-four male Wistar rats were anesthetized and randomly divided into four groups (n = 6 per group): sham-operated (sham); brain death only (BD); brain death plus methylprednisolone (30 mg/kg i.v.) after 5 min (MP5); and brain death plus methylprednisolone (30 mg/kg i.v.) after 60 min (MP60). In the BD, MP5, and MP60 group rats, we induced brain death by inflating a balloon catheter in the extradural space. All of the animals were observed and ventilated for 120 min. We determined hemodynamic and arterial blood gas variables; wet/dry weight ratio; histological score; levels of thiobarbituric acid reactive substances (TBARS); superoxide dismutase (SOD) activity; and catalase activity. In BAL fluid, we determined differential white cell counts, total protein, and lactate dehydrogenase levels. Myeloperoxidase activity, lipid peroxidation, and TNF-α levels were assessed in lung tissue.

RESULTS:

No significant differences were found among the groups in terms of hemodynamics, arterial blood gases, wet/dry weight ratio, BAL fluid analysis, or histological score-nor in terms of SOD, myeloperoxidase, and catalase activity. The levels of TBARS were significantly higher in the MP5 and MP60 groups than in the sham and BD groups (p < 0.001). The levels of TNF-α were significantly lower in the MP5 and MP60 groups than in the BD group (p < 0.001).

CONCLUSIONS:

In this model of brain death, the early and late administration of methylprednisolone had similar effects on inflammatory activity and lipid peroxidation in lung tissue.

Pharmacotherapy of Lung Transplantation

Lung transplantation has become a viable treatment therapy for end-stage lung disease patients. The most common etiologies of end-stage lung disease, which can require a transplant are chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), pulmonary arterial hypertension (PAH), and pulmonary fibrosis (PF). Listing criteria are institution and program specific. Approximately 1500 lung transplants were performed in 2008; and at 5 years post transplant, one-half are expected to survive. The surgery itself is associated with various complications, including surgical, infectious, and mechanical. Immunosuppression is paramount to the management of these patients, the goal being prevention of T cell activation to prevent rejection of the new organ. The patients commonly receive an induction agent with a T cell depleting antibody and high-dose corticosteroids. Maintenance immunosuppression begins immediately after the surgery, consisting of a combination of a calcineurin inhibitor, antimetabolite, and corticosteroids. Side effect profiles from the various agents will determine the choice of agents, and patients may have modifications throughout the therapy. The role of the pharmacist spans the inpatient management of acute complications to medication selection, management of maintenance immunosuppression, as well as monitoring for adverse drug reactions and drug–drug interactions. A multidisciplinary collaborative approach must be taken to ensure the best outcomes for this patient population.

Critical care aspects of lung transplantation

Lung transplantation currently is the preferred treatment option for a variety of end-stage pulmonary diseases. Remarkable progress has occurred through refinements in technique and improved understanding of transplant immunology and microbiology. As a result, recipients are surviving longer after their transplant. Despite improvements in short- and intermediate-term survival, long-term success with lung transplantation remains limited by chronic allograft rejection, also known as bronchiolitis obliterans syndrome. Despite its long-term limitations, lung transplantation remains the only hope for many with end-stage pulmonary disease, and during the past 20 years, it has become increasingly accepted and used. As a result, clinicians working in an intensive care unit (ICU) are more likely to be exposed to these patients both in the immediate postoperative period as well as throughout their remaining lives. It is thus important that the ICU team have a working knowledge of the common complications, when these complications are most likely to occur, and how best to treat them when they do arise. The main focus of this review is to address the variety of potential graft and life-threatening problems that may occur in lung transplant recipients. Because the ICU is also the most common setting where a potential donor is identified, donor issues will briefly be addressed.