Examination of the Ability of N-acetylcysteine Administration during Anesthesia to Prevent Perioperative Deterioration of Pulmonary Function in Patients Undergoing Nephrectomy.

BACKGROUND: Postoperative pulmonary complications are associated with significant morbidity and mortality in patients undergoing major surgeries. Acetylcysteine is a known antioxidant and is also used as a mucolytic agent to reduce hypersecretion and the viscosity of mucus secretions by the lung. Several studies have revealed that high doses of N-acetylcysteine can significantly prevent pulmonary complications. However, it has not yet been established whether low doses of N-acetylcysteine are also of clinical benefit. Here, we investigated the efficacy of a low dose of N-acetylcysteine, which was administered intravenously to patients under general anesthesia, in preventing perioperative deterioration of pulmonary function. METHODS: A total of 52 patients who were scheduled for nephrectomy were randomly assigned to receive either 600 mg of intravenous N-acetylcysteine or the same volume of normal saline. Patient hemodynamic and pulmonary parameters and the incidence of pulmonary complications were recorded and compared between the groups. RESULTS: No significant pulmonary complications occurred in either group. Moreover, no significant differences were observed regarding either patient characteristics or hemodynamic parameters between the two groups. Contrary to our expectations, the pulmonary parameters were also not significantly different between the two groups. CONCLUSION: A low dose of N-acetylcysteine appears to have only limited value in preventing perioperative pulmonary complications.

Identification of a new functional domain in angiopoietin-like 3 (ANGPTL3) and angiopoietin-like 4 (ANGPTL4) involved in binding and inhibition of lipoprotein lipase (LPL).

Angiopoietin-like 3 (ANGPTL3) and angiopoietin-like 4 (ANGPTL4) are secreted proteins that regulate triglyceride (TG) metabolism in part by inhibiting lipoprotein lipase (LPL). Recently, we showed that treatment of wild-type mice with monoclonal antibody (mAb) 14D12, specific for ANGPTL4, recapitulated the Angptl4 knock-out (-/-) mouse phenotype of reduced serum TG levels. In the present study, we mapped the region of mouse ANGPTL4 recognized by mAb 14D12 to amino acids Gln(29)-His(53), which we designate as specific epitope 1 (SE1). The 14D12 mAb prevented binding of ANGPTL4 with LPL, consistent with its ability to neutralize the LPL-inhibitory activity of ANGPTL4. Alignment of all angiopoietin family members revealed that a sequence similar to ANGPTL4 SE1 was present only in ANGPTL3, corresponding to amino acids Glu(32)-His(55). We produced a mouse mAb against this SE1-like region in ANGPTL3. This mAb, designated 5.50.3, inhibited the binding of ANGPTL3 to LPL and neutralized ANGPTL3-mediated inhibition of LPL activity in vitro. Treatment of wild-type as well as hyperlipidemic mice with mAb 5.50.3 resulted in reduced serum TG levels, recapitulating the lipid phenotype found in Angptl3(-/-) mice. These results show that the SE1 region of ANGPTL3 and ANGPTL4 functions as a domain important for binding LPL and inhibiting its activity in vitro and in vivo. Moreover, these results demonstrate that therapeutic antibodies that neutralize ANGPTL4 and ANGPTL3 may be useful for treatment of some forms of hyperlipidemia.