Systemic administration of a centrally acting acetylcholinesterase inhibitor improves outcome from hemorrhagic shock during acute alcohol intoxication

Therapeutic effects of physostigmine during systemic inflammation

Introduction

Usually, physostigmine is used as antidote for anticholinergic poisons in order to improve hemodynamics and cardiac output. In addition, it causes beneficial effects during sepsis when added timely. Here, we studied whether physostigmine improves hemodynamics when treatment during systemic inflammation was delayed.

Methods

Two series of randomized studies with overall 44 rats were conducted. Systemic inflammation was induced by lipopolysaccharide (LPS) infusion (0.5 mg LPS/kg×h). Physostigmine (PHY) was intravenously applied after an LPS infusion period of 90 minutes (50 µg PHY/kg within 10 minutes) with (series 1) and without (series 2) additional volume loading. Hemodynamic parameters, blood gases, and parameters for tissue damage were periodically determined for up to 180 minutes.

Results

Even though volume was additionally administered (series 1), LPS caused a reduction of peripheral blood flow. Treatment with PHY improved hemodynamics in macrocirculation (mean arterial blood pressure) and microcirculation (peripheral blood flow). PHY neither affected alterations in blood gases, electrolyte homeostasis, and glucose metabolism nor prevented intestinal damage induced by LPS. In series 2, without any additional volume loading, PHY likewise resulted in an improvement of the LPS-induced alterations in macro- and microcirculation, but finally worsened the LPS-mediated effects on plasma parameters for tissue damage such as creatine kinase, probably due to the lack of volume and a further damage to the heart.

Conclusion

The present results demonstrated that hemodynamic responses to PHY may not only be visible in patients with anticholinergic drug overdose but also be visible in septic patients, provided that fluid intake of these patients is adequate.

Free radical production and antioxidant status in brain cortex non-synaptic mitochondria and synaptosomes at alcohol hangover onset

Alcohol hangover (AH) is the pathophysiological state after a binge-like drinking. We have previously demonstrated that AH induced bioenergetics impairments in a total fresh mitochondrial fraction in brain cortex and cerebellum. The aim of this work was to determine free radical production and antioxidant systems in non-synaptic mitochondria and synaptosomes in control and hangover animals. Superoxide production was not modified in non-synaptic mitochondria while a 17.5% increase was observed in synaptosomes. A similar response was observed for cardiolipin content as no changes were evidenced in non-synaptic mitochondria while a 55% decrease in cardiolipin content was found in synaptosomes. Hydrogen peroxide production was 3-fold increased in non-synaptic mitochondria and 4-fold increased in synaptosomes. In the presence of deprenyl, synaptosomal H₂O₂ production was 67% decreased in the AH condition. Hydrogen peroxide generation was not affected by deprenyl addition in non-synaptic mitochondria from AH mice. MAO activity was 57% increased in non-synaptic mitochondria and 3-fold increased in synaptosomes. Catalase activity was 40% and 50% decreased in non-synaptic mitochondria and synaptosomes, respectively. Superoxide dismutase was 60% decreased in non-synaptic mitochondria and 80% increased in synaptosomal fractions. On the other hand, GSH (glutathione) content was 43% and 17% decreased in synaptosomes and cytosol. GSH-related enzymes were mostly affected in synaptosomes fractions by AH condition. Acetylcholinesterase activity in synaptosomes was 11% increased due to AH. The present work reveals that AH provokes an imbalance in the cellular redox homeostasis mainly affecting mitochondria present in synaptic terminals.

Acute alcohol exposure has an independent impact on C-reactive protein levels, neutrophil CD64 expression, and subsets of circulating white blood cells differentiated by flow cytometry in nontrauma patients

Acute and massive alcohol exposure (blood alcohol concentration of ≥1 g/L) is a common way to consume alcohol. In a prospective study performed in critically ill nontrauma patients, we compared C-reactive protein (CRP) values, circulating subsets of white blood cells, and neutrophil CD64 indexes recorded at admission to the intensive care unit between abstinent or moderate drinkers (n = 173), patients with acute or chronic alcohol exposure (n = 32), and patients with acute exposure but not chronically exposed to alcohol (n = 27). Values for CRP (P < 0.001), circulating neutrophils (P < 0.001), and neutrophil CD64 indexes (P < 0.001) were significantly lower in patients acutely exposed compared with the other patients, whereas values for B lymphocytes (P < 0.001) and cytotoxic (P < 0.001) and noncytotoxic T lymphocytes (P < 0.001) were significantly higher. After multiple regression analysis, alcohol exposure remained independently associated with values of CRP, neutrophils CD4 indexes, cytotoxic and noncytotoxic T lymphocytes, and CD16-negative and -positive monocytes. These results were not affected by the presence or absence of infection at admission. Our results suggest that in nontrauma critically ill patients, acute alcohol exposure diminishes inflammation and increases numbers of circulating B and T lymphocytes.

Alcohol abuse and the injured host: dysregulation of counterregulatory mechanisms review

Traumatic injury ranks as the number one cause of death for the younger than 44 years age group and fifth leading cause of death overall (www.nationaltraumainstitute.org/home/trauma_statistics.html). Although improved resuscitation of trauma patients has dramatically reduced immediate mortality from hemorrhagic shock, long-term morbidity and mortality continue to be unacceptably high during the postresuscitation period particularly as a result of impaired host immune responses to subsequent challenges such as surgery or infection. Acute alcohol intoxication (AAI) is a significant risk factor for traumatic injury, with intoxicating blood alcohol levels present in more than 40% of injured patients. Severity of trauma, hemorrhagic shock, and injury is higher in intoxicated individuals than that of sober victims, resulting in higher mortality rates in this patient population. Necessary invasive procedures (surgery, anesthesia) and subsequent challenges (infection) that intoxicated trauma victims are frequently subjected to are additional stresses to an already compromised inflammatory and neuroendocrine milieu and further contribute to their morbidity and mortality. Thus, dissecting the dynamic imbalance produced by AAI during trauma is of critical relevance for a significant proportion of injured victims. This review outlines how AAI at the time of hemorrhagic shock not only prevents adequate responses to fluid resuscitation but also impairs the ability of the host to overcome a secondary infection. Moreover, it discusses the neuroendocrine mechanisms underlying alcohol-induced hemodynamic dysregulation and its relevance to host defense restoration of homeostasis after injury.

Hypertonic saline resuscitation enhances blood pressure recovery and decreases organ injury following hemorrhage in acute alcohol intoxicated rodents

BACKGROUND

Acute alcohol intoxication (AAI) impairs the hemodynamic and arginine vasopressin (AVP) counter-regulation to hemorrhagic shock (HS) and lactated Ringer's solution (LR) fluid resuscitation (FR). The mechanism of AAI-induced suppression of AVP release in response to HS involves accentuated nitric oxide (NO) inhibitory tone. In contrast, AAI does not prevent AVP response to increased osmolarity produced by hypertonic saline (HTS) infusion. We hypothesized that FR with HTS during AAI would enhance AVP release by decreasing periventricular nucleus NO inhibitory tone, subsequently improving mean arterial blood pressure (MABP) and organ perfusion.

METHODS

Male Sprague-Dawley rats received a 15-hour alcohol infusion (2.5 g/kg + 0.3 g/kg/h) or dextrose (DEX) before HS (40 mm Hg × 60 minutes) and FR with HTS (7.5%, 4 ml/kg) or LR (2.4 × blood volume removed). Organ blood flow was determined, and brains were collected for NO content at 2 hours after FR.

RESULTS

HTS improved MABP recovery in AAI (109 vs. 80 mm Hg) and DEX (114 vs. 83 mm Hg) animals compared with LR. This was associated with higher (>60%) circulating AVP levels at 2 hours after FR compared with those detected in LR animals in both groups. Neither AAI alone nor HS in DEX animals resuscitated with LR altered organ blood flow. In AAI animals, HS and FR with LR reduced blood flow to the liver (72%), small intestine (65%), and large intestine (67%) compared with shams. FR with HTS improved liver (threefold) and small intestine (twofold) blood flow compared with LR in AAI-HS animals. The enhanced MABP response to HTS was prevented by pretreatment with a systemic AVP V1a receptor antagonist. HTS decreased periventricular nucleus NO content in both groups 2 hours after FR.

CONCLUSION

These results suggest that FR with HTS in AAI results in the removal of central NO inhibition of AVP, restoring AVP levels and improving MABP and organ perfusion in AAI-HS.

Ethanol consumption impairs the hemodynamic response to hemorrhagic shock in rats

Alcohol intoxication can exacerbate hemodynamic instability following hemorrhagic shock. Impairment of hormonal, neurohumoral, and immune responses can contribute to such instability; however, the relationship between blood alcohol levels and the progression of hemorrhagic shock accompanied with these responses has not been clearly demonstrated. Herein, we examined this relationship in rats treated with various dose of alcohol. After oral administration of alcohol and then hemorrhage, the recovery of mean blood pressure (MBP); increase in plasma level of norepinephrine, epinephrine, and vasopressin; and survival interval decreased in a dose-dependent manner as the blood alcohol level increased. There were no significant differences in the production of proinflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β among the groups. The present results demonstrated alcohol aggravates hemorrhagic shock in a dose-dependent manner not by alerting the immune response, but by suppressing hormonal and neurohumoral responses, thereby inhibiting hemodynamic autoregulation and shortening the survival interval.

Combined administration of anisodamine and neostigmine produces anti-shock effects: involvement of α7 nicotinic acetylcholine receptors

AIM

To evaluate the anti-effects of anisodamine and neostigmine in animal models of endotoxic and hemorrhagic shock.

METHODS

Kunming mice were injected with lipopolysaccharide (LPS 30 mg/kg, ip) to induce endotoxic shock. Anisodamine (12.5, 25, and 50 mg/kg, ip) and neostigmine (12.5, 25, and 50 μg/kg, ip) were administered immediately after LPS injection. Survival rate was monitored, and the serum levels of TNF-α and IL-1β were analyzed using ELISA assays. The effects of anisodamine and neostigmine were also examined in α7 nicotinic acetylcholine receptor (α7 nAChR) knockout mice with endotoxic shock and in Beagle dogs with hemorrhagic shock.

RESULTS

In mice with experimental endotoxemia, combined administration of anisodamine and neostigmine significantly increased the survival rate and decreased the serum levels of inflammatory cytokines, as compared to those produced by either drug alone. The anti-shock effect of combined anisodamine and neostigmine was abolished in α7 nAChR knockout mice. On the other hand, intravenous injection of the combined anisodamine and neostigmine, or the selective α7 nAChR agonist PNU282987 exerted similar anti-shock effects in dogs with hemorrhagic shock.

CONCLUSION

The results demonstrate that combined administration of anisodamine and neostigmine produces significant anti-shock effects, which involves activation of α7 nAChRs.

Delayed resuscitation with physostigmine increases end organ damage in alcohol intoxicated rats

Previous studies from our laboratory have identified a role for blunted central sympathetic activation in the acute alcohol intoxication (AAI)-induced impairment of the counterregulatory response to hemorrhagic shock (HS). Immediate fluid resuscitation (FR) with acetylcholinesterase inhibitors restores the neuroendocrine and pressor responses to FR in AAI + HS. We hypothesized this intervention would remain beneficial after delay and that restoration of mean arterial blood pressure (MABP) during FR would attenuate organ damage. Male Sprague-Dawley rats received a primed constant alcohol infusion (2.5 g · kg + 0.3 g · kg · h for 15 h) or isocaloric dextrose (DEX) before HS (40 mmHg for 60 min) and FR with lactated Ringer's (LR) solution ± physostigmine (PHYS; 100 µg · kg) immediately or after a 60-min delay after HS. Immediate LR solution elevated MABP in DEX + HS. Acute alcohol intoxication delayed the initial MABP recovery. Delayed LR solution did not further increase MABP in DEX- or AAI + HS. LR solution + PHYS increased MABP in DEX- and AAI + HS after immediate and delayed FR. No differences were noted in markers of organ dysfunction (alanine aminotransferase [ALT], aspartate aminotransferase, blood urea nitrogen, creatinine) after DEX + HS, and this was unaltered by immediate or delayed LR solution + PHYS. Acute alcohol intoxication + HS increased ALT, which was attenuated by immediate LR solution + PHYS. In contrast, delayed LR solution + PHYS exacerbated tissue injury in AAI + HS, as reflected by increased ALT, aspartate aminotransferase, blood urea nitrogen, creatinine, and liver protein carbonylation over time-matched LR solution. In conclusion, PHYS enhanced blood pressure recovery independent of time of FR and presence of AAI. However, in AAI + HS, delayed LR solution + PHYS accentuated organ damage and dysfunction. These findings suggest that although enhancing the sympathetic response can improve hemodynamic recovery during AAI, it may compromise tissue perfusion and enhance tissue injury.