N-Acetylcysteine attenuates tumor necrosis factor alpha levels in autoimmune inner ear disease patients

Autoimmune inner ear disease (AIED) is a poorly understood disease marked by bilateral, rapidly progressive hearing loss triggered by unknown stimuli, which is corticosteroid responsive in 60 % of patients. Although the mechanism of the disease is not precisely understood, a complex interaction of cytokines is believed to contribute toward the inflammatory disease process and hearing loss. Previously, we showed the role of TNF-alpha in steroid-sensitive and IL-1beta in steroid-resistant immune-mediated hearing loss. N-Acetylcysteine (NAC), a broad spectrum antioxidant, has been effective in other autoimmune disorders. Other studies have shown NAC to have a protective adjunct role in human idiopathic sudden hearing loss, where the addition of NAC resulted in better hearing recovery than with steroids alone, although the mechanism of this protection was not elucidated. In the present study, we observed PBMCs from AIED patients exhibited higher baseline TNF-alpha and MPO levels compared with normal healthy controls. NAC effectively abrogates LPS-mediated TNF-alpha release from PBMC of both AIED patients and controls. We demonstrated that in AIED patients, the TNF-alpha downstream signaling pathway appears aberrantly regulated, influencing both MPO and IL-8 expression. Given that NAC effectively abrogated LPS-mediated TNF-alpha release and exerted minimal effects on the downstream targets of this pathway, we feel NAC may be a rational adjunct therapy for this enigmatic disease, worthy of clinical exploration

Anti-septic effects of pelargonidin on HMGB1-induced responses in vitro and in vivo

A certain nucleosomal protein-high mobility group box-1 (HMGB1)-has recently been established as a late mediator of sepsis, with a relatively wide therapeutic window for pharmacological intervention. Pelargonidin (PEL) is a well-known red pigment found in plants; it has important biological activities that are potentially beneficial for human health. In the present study, we investigated whether PEL can modulate HMGB1-mediated inflammatory responses in human umbilical vein endothelial cells (HUVECs) and in mice. The anti-inflammatory activities of PEL were determined by measuring permeability, leukocyte adhesion and migration, and activation of pro-inflammatory proteins in HMGB1-activated HUVECs and mice, as well as the beneficial effects of PEL on survival rate in the mouse sepsis model. The data showed that PEL had effectively inhibited lipopolysaccharide (LPS)-induced release of HMGB1 and suppressed HMGB1-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. Furthermore, PEL inhibited the HMGB1-mediated production of tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6), as well as the activation of nuclear factor-kappa B (NF-kappa B) and extracellular signal-regulated kinases 1 and 2 (ERK1/2). Collectively, these results indicate that PEL could be used to treat various severe vascular inflammatory diseases via the inhibition of the HMGB1 signaling pathway.close