Biphasic Modulation of NOS Expression, Protein and Nitrite Products by Hydroxocobalamin Underlies Its Protective Effect in Endotoxemic Shock: Downstream Regulation of COX-2, IL-1β, TNF-α, IL-6, and HMGB1 Expression

Abstract

Background. NOS/•NO inhibitors are potential therapeutics for sepsis, yet they increase clinical mortality. However, there has been no in vivo investigation of the (in vitro) •NO scavenger, cobalamin's (Cbl) endogenous effects on NOS/•NO/inflammatory mediators during the immune response to sepsis. Methods. We used quantitative polymerase chain reaction (qPCR), ELISA, Western blot, and NOS Griess assays, in a C57BL/6 mouse, acute endotoxaemia model. Results. During the immune response, pro-inflammatory phase, parenteral hydroxocobalamin (HOCbl) treatment partially inhibits hepatic, but not lung, iNOS mRNA and promotes lung eNOS mRNA, but attenuates the LPS hepatic rise in eNOS mRNA, whilst paradoxically promoting high iNOS/eNOS protein translation, but relatively moderate •NO production. HOCbl/NOS/•NO regulation is reciprocally associated with lower 4 h expression of TNF-α, IL-1β, COX-2, and lower circulating TNF-α, but not IL-6. In resolution, 24 h after LPS, HOCbl completely abrogates a major late mediator of sepsis mortality, high mobility group box 1 (HMGB1) mRNA, inhibits iNOS mRNA, and attenuates LPS-induced hepatic inhibition of eNOS mRNA, whilst showing increased, but still moderate, NOS activity, relative to LPS only. experiments (LPS+D-Galactosamine) HOCbl afforded significant, dose-dependent protection in mice Conclusions. HOCbl produces a complex, time- and organ-dependent, selective regulation of NOS/•NO during endotoxaemia, corollary regulation of downstream inflammatory mediators, and increased survival. This merits clinical evaluation.

Anti‐inflammatory and anti‐insulin resistance activities of aqueous extract from Anoectochilus burmannicus

“…The overproduction of these mediators has been related in several diseases caused by inflammation, such as obesity‐related insulin resistance (Xu et al., 2003), rheumatoid arthritis (Shrivastava et al., 2015), cancer (Chua, Chong, Liauw, Zhao, & Morris, 2012), atherosclerosis (Hamirani et al., 2014), and hepatitis (Connoy, Turner, & Nunez, 2011). Increasing in NO in the activated macrophages could induce a host‐defense mechanism and cellular or tissues damages leading to an inflammation (Ialenti, Ianaro, Moncada, & Di Rosa, 1992; Sampaio et al., 2013; Sharma, Al‐Omran, & Parvathy, 2007). Moreover, the level of NO has been used as a marker for the diagnosis and monitoring of response to anti‐inflammatory therapy (Zitt, 2005).…”

A Prospective, Randomized Trial of Intravenous Hydroxocobalamin Versus Whole Blood Transfusion Compared to No Treatment for Class III Hemorrhagic Shock Resuscitation in a Prehospital Swine Model

“…Whereas experiments using nitric oxide synthase inhibitors have had mixed results because the compounds inhibit both inducible and constitutive nitric oxide synthase, [33][34][35][36] nitric oxide scavengers have shown promise. 13,37,38 In this study, cardiac output in the IV hydroxocobalamin group was significantly lower compared to whole blood group, but not the control group. We speculate that cardiac output was decreased in the IV hydroxocobalamin group because hydroxocobalamin produced an increase in systemic vascular resistance via nitric oxide scavenging.…”

“…16 Animal models suggest that hydroxocobalamin scavenges nitric oxide and regulates nitric oxide and nitric oxide synthase selectively. 13,16 Hence, in our model, hydroxocobalamin increased systemic vascular resistance significantly compared to whole blood or no treatment and produced a concomitant decrease in cardiac output. This outcome was not unexpected and may be beneficial when blood products are unavailable.…”

“…Although IV hydroxocobalamin produced a significant increase in systemic vascular resistance compared to the control group, but not the whole blood group, this may be attributed to its nitric oxide scavenging properties. 13,16 Nitric oxide synthase has been shown to be upregulated in hemorrhagic shock 31 and septic shock, 32 resulting in a large release of nitric oxide, hence the scientific interest in nitric oxide scavengers or nitric oxide synthase inhibitors for the treatment of shock. Whereas experiments using nitric oxide synthase inhibitors have had mixed results because the compounds inhibit both inducible and constitutive nitric oxide synthase, [33][34][35][36] nitric oxide scavengers have shown promise.…”

“…10 Hydroxocobalamin has been shown to effectively increase blood pressure in cyanide-induced cardiac arrest and endotoxin-induced hypotension. [11][12][13] In previous studies examining the efficacy of hydroxocobalamin to treat cyanide toxicity in a swine model of acute severe cyanide toxicity, it also improved blood pressure, heart rate, and lactate levels. 14,15 Hydroxocobalamin has been shown to improve blood pressure likely through nitric oxide scavenging, when administered in a small volume, and may be an ideal resuscitation treatment prior to the availability of blood.…”