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

Cellular and molecular mechanisms of hepatic ischemia-reperfusion injury: The role of oxidative stress and therapeutic approaches

Ischemia-reperfusion (IR) or reoxygenation injury is the paradoxical exacerbation of cellular impairment following restoration of blood flow after a period of ischemia during surgical procedures or other conditions. Acute interruption of blood supply to the liver and subsequent reperfusion can result in hepatocyte injury, apoptosis, and necrosis. Since the liver requires a continuous supply of oxygen for many biochemical reactions, any obstruction of blood flow can rapidly lead to hepatic hypoxia, which could quickly progress to absolute anoxia. Reoxygenation results in the increased generation of reactive oxygen species and oxidative stress, which lead to the enhanced production of proinflammatory cytokines, chemokines, and other signaling molecules. Consequent acute inflammatory cascades lead to significant impairment of hepatocytes and nonparenchymal cells. Furthermore, the expression of several vascular growth factors results in the heterogeneous closure of numerous hepatic sinusoids, which leads to reduced oxygen supply in certain areas of the liver even after reperfusion. Therefore, it is vital to identify appropriate therapeutic modalities to mitigate hepatic IR injury and subsequent tissue damage. This review covers all the major aspects of cellular and molecular mechanisms underlying the pathogenesis of hepatic ischemia-reperfusion injury, with special emphasis on oxidative stress, associated inflammation and complications, and prospective therapeutic approaches.

Early Hypocalcemia in Severe Trauma: An Independent Risk Factor for Coagulopathy and Massive Transfusion

The rapid identification of patients at risk for massive blood transfusion is of paramount importance as uncontrolled exsanguination may lead to death within 2 to 6 h. The aim of this study was to analyze a cohort of severe trauma patients to identify risk factors associated with massive transfusion requirements and hypocalcemia. All major trauma (ISS > 16) presented directly from the scene to the Niguarda hospital between 1 January 2015 and 31 December 2021 were analyzed. A total of 798 patients were eligible out of 1586 screened. Demographic data showed no significant difference between hypocalcemic (HC) and normocalcemic (NC) patients except for the presence of crush trauma, alcohol intake (27% vs. 15%, p < 0.01), and injury severity score (odds ratio 1.03, p = 0.03). ISS was higher in the HC group and was an independent, even if weak, predictor of hypocalcemia (odds ratio 1.03, p = 0.03). Prehospital data showed a lower mean systolic arterial pressure (SAP) and a higher heart rate (HR) in the HC group (105 vs. 127, p < 0.01; 100 vs. 92, p < 0.001, respectively), resulting in a higher shock index (SI) (1.1 vs. 0.8, p < 0.001). Only retrospective studies such as ours are available, and while hypocalcemia seems to be an independent predictor of mortality and massive transfusion, there is not enough evidence to support causation. Therefore, randomized prospective studies are suggested.

Spontaneously hypertensive rats exhibit higher sensitivity to ethanol-induced hypotensive effects: Role of NMDA receptors and nitric oxide in rostral ventrolateral medulla

Intake of ethanol (alcohol) affects cardiovascular function. Acute ethanol intake has been shown to lower blood pressure (BP) in hypertensive patients. The present study was undertaken to examine the effects and mechanisms of acute administration of ethanol on BP in hypertensive and normotensive rats. Ethanol was given by intraperitoneal (i.p.) injection in male spontaneously hypertensive rats (SHRs) and the normotensive Wistar-Kyoto rats (WKYs). BP responses were measured in free-moving conscious rats or in urethane-anesthetized rats. Inhibitors were applied by bilateral microinjection into the rostral ventrolateral medulla (RVLM). Nitric oxide (NO•) levels and glutamate levels were determined by nitrate and nitrite (NOx) analyzer and HPLC-ECD, respectively. Intraperitoneal (i.p.) injection of ethanol (1.6 g/kg) caused a significant decrease in BP in free-moving or in anesthetized SHRs but not in WKYs. A higher dose (3.2 g/kg) of ethanol decreased BP in both SHRs and WKYs, although the depressor responses in SHRs occurred significantly earlier than those in WKYs. The blood ethanol concentrations 60 min after injection were similar in SHRs and WKYs. Bilateral microinjection of nitric oxide synthase (NOS) inhibitors or glutamatergic NMDA receptor antagonists into the RVLM 5 min after administration of ethanol significantly inhibited the ethanol-induced depressor effects in SHRs. The levels of NOx and glutamate release in the RVLM following ethanol administration and the NOx content in the RVLM areas 30 min after administration were significantly increased in SHRs, but not in WKYs. Our results showed that SHRs were more sensitive to ethanol-induced hypotensive effects than WKYs because of augmentation of ethanol-induced expression of the glutamatergic NMDA receptor/NO• signal in the RVLM of SHRs.

Binge Drinking's Effects on the Body

Studies have focused on the effects of chronic alcohol consumption and the mechanisms of tissue injury underlying alcoholic hepatitis and cirrhosis, with less focus on the pathophysiological consequences of binge alcohol consumption. Alcohol binge drinking prevalence continues to rise, particularly among individuals ages 18 to 24. However, it is also frequent in individuals ages 65 and older. High blood alcohol levels achieved with this pattern of alcohol consumption are of particular concern, as alcohol can permeate to virtually all tissues in the body, resulting in significant alterations in organ function, which leads to multisystemic pathophysiological consequences. In addition to the pattern, amount, and frequency of alcohol consumption, additional factors, including the type of alcoholic beverage, may contribute differentially to the risk for alcohol-induced tissue injury. Preclinical and translational research strategies are needed to enhance our understanding of the effects of binge alcohol drinking, particularly for individuals with a history of chronic alcohol consumption. Identification of underlying pathophysiological processes responsible for tissue and organ injury can lead to development of preventive or therapeutic interventions to reduce the health care burden associated with binge alcohol drinking.

Mitochondrial dysfunction in rat splenocytes following hemorrhagic shock

The regulation of mitochondrial function is critical in cellular homeostasis following hemorrhagic shock. Hemorrhagic shock results in fluid loss and reduced availability of oxygen and nutrients to tissues. The spleen is a secondary lymphoid organ playing a key role in 'filtering the blood' and in the innate and adaptive immune responses. To understand the molecular basis of hemorrhagic shock, we investigated the changes in splenocyte mitochondrial respiration, and concomitant immune and metabolic alterations. The hemorrhagic injury (HI) in our rat model was induced by bleeding 60% of the total blood volume followed by resuscitation with Ringers lactate. Another group of animals was subjected to hemorrhage, but did not receive fluid resuscitation. Oxygen consumption rate of splenocytes were determined using a Seahorse analyzer. We found a significantly reduced oxygen consumption rate in splenocytes following HI compared to sham operated rats. The mitochondrial stress test revealed a decreased basal oxygen consumption rate, ATP production, maximal respiration and spare respiratory capacity. The mitochondrial membrane potential, and citrate synthase activity, were also reduced in the splenocytes following HI. Hypoxic response in the splenocyte was confirmed by increased gene expression of Hif1α. Elevated level of mitochondrial stress protein, hsp60 and induction of high mobility group box1 protein (HMGB1) were observed in splenocytes following HI. An increased inflammatory response was demonstrated by significantly increased expression of IL-6, IFN-β, Mip-1α, IL-10 and NFκbp65. In summary, we conclude that splenocyte oxidative phosphorylation and metabolism were severely compromised following HI.

Alcohol use disorder increases the risk of necrotizing fasciitis: A nationwide retrospective cohort study

This nationwide retrospective cohort study determined the association between alcohol use disorder (AUD) and the risk of necrotizing fasciitis (NF).This study used health insurance claims data of 52,212 in-patients with AUD and 208,848 controls randomly frequency-matched by age and sex at a 1:4 ratio. The AUD cohort included patients newly diagnosed with AUD between January 1, 2000 and December 31, 2008. The NF event occurrence was observed until December 31, 2011. We used the Kaplan-Meier method to present the cumulative incidence curve and Cox proportional hazard models to depict the risk of NF in patients with AUD.The incidence of NF was 19.4 per 10,000 person-years in the AUD cohort, which was nearly 7.73-fold higher than that in the comparison cohort (2.54 per 10,000 person-years). After adjustment for age, sex, and comorbidities, the patients with AUD exhibited a 3.55-fold higher risk of NF than did the controls (hazard ratio [HR] = 3.55, 95% confidence interval [CI] = 3.00-4.20). Nevertheless, in the AUD groups without any comorbidity, patients with AUD exhibited a significant 15.2-fold higher risk of NF than did the comparison cohort (HR = 15.2, 95% CI = 10.9-21.3). Moreover, the adjusted HRs of NF risk with respect to the severity of AUD were 2.15 (95% CI = 1.76-2.62), 4.54 (95% CI = 3.67-5.62), and 10.7 (95% CI = 8.66-13.2) for mild, moderate, and severe AUD, respectively.This study indicated that AUD should be considered an independent and significant risk factor for NF.

Alcohol and mortality after moderate to severe traumatic brain injury: a meta-analysis of observational studies

OBJECT

Experimental studies have shown numerous neuroprotective properties of alcohol (“ethanol”) after TBI, but clinical studies have provided conflicting results. The authors aimed to assess the relationship between positive blood alcohol concentration (BAC) on hospital admission and mortality after moderate to severe traumatic brain injury (TBI).

METHODS

The authors searched 8 databases for observational studies reported between January 1, 1990, and October 7, 2013, and investigated the effect of BAC on mortality after moderate to severe TBI. Reviews of each study were conducted, and data were extracted according to the MOOSE and PRISMA guidelines. Study quality was assessed using the Newcastle-Ottawa scale. The Mantel-Haenszel fixed effect methodology was used to generate pooled estimates. Heterogeneity was dealt with by multiple sensitivity analyses.

RESULTS

Eleven studies with a total of 95,941 patients (42% BAC positive and 58% BAC negative) were identified for the primary analysis (overall mortality 12%). Primary analysis showed a significantly lower risk of death for BAC-positive patients compared with BAC-negative patients (crude mortality 11.0% vs 12.3%, pooled OR 0.84 [95% CI 0.81–0.88]), although flawed by heterogeneity (I2 = 68%). Multiple sensitivity analyses, including 55,949 and 51,772 patients, yielded similar results to the primary analysis (crude mortality 12.2% vs 14.0%, pooled OR 0.87 [95% CI 0.83–0.92] and crude mortality 8.7% vs 10.7%, pooled OR 0.78 [95% CI 0.74–0.83]) but with good study homogeneity (I2 = 36% and 14%).

CONCLUSIONS

Positive BAC was significantly associated with lower mortality rates in moderate to severe TBI. Whether this observation is due to selection bias or neuroprotective effects of alcohol remains unknown. Future prospective studies adjusting for TBI heterogeneity is advocated to establish the potential favorable effects of alcohol on outcome after TBI.

Intestine immune homeostasis after alcohol and burn injury

Traumatic injury remains one of the most prevalent reasons for patients to be hospitalized. Burn injury accounts for 40,000 hospitalizations in the United States annually, resulting in a large burden on both the health and economic system and costing millions of dollars every year. The complications associated with postburn care can quickly cause life-threatening conditions including sepsis and multiple organ dysfunction and failure. In addition, alcohol intoxication at the time of burn injury has been shown to exacerbate these problems. One of the biggest reasons for the onset of these complications is the global suppression of the host immune system and increased susceptibility to infection. It has been hypothesized that infections after burn and other traumatic injury may stem from pathogenic bacteria from within the host's gastrointestinal tract. The intestine is the major reservoir of bacteria within the host, and many studies have demonstrated perturbations of the intestinal barrier after burn injury. This article reviews the findings of these studies as they pertain to changes in the intestinal immune system after alcohol and burn injury.

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.

Acute immunomodulatory effects of binge alcohol ingestion

BACKGROUND

Blood alcohol is present in a third of trauma patients and has been associated with organ dysfunction. In both human studies and in animal models, it is clear that alcohol intoxication exerts immunomodulatory effects several hours to days after exposure, when blood alcohol is no longer detectable. The early immunomodulatory effects of alcohol while blood alcohol is still elevated are not well understood.

METHODS

Human volunteers achieved binge alcohol intoxication after high-dose alcohol consumption. Blood was collected for analysis prior to alcohol ingestion, and 20 min, 2 h, and 5 h after alcohol ingestion. Flow cytometry was performed on isolated peripheral blood mononuclear cells, and cytokine generation in whole blood was measured by enzyme-linked immunosorbent assay (ELISA) after 24-h stimulation with lipopolysaccharide (LPS) and phytohemagglutinin-M (PHA) stimulation.

RESULTS

An early pro-inflammatory state was evident at 20 min when blood alcohol levels were ∼130 mg/dL, which was characterized by an increase in total circulating leukocytes, monocytes, and natural killer cells. During this time, a transient increase in LPS-induced tumor necrosis factor (TNF)-α levels and enhanced LPS sensitivity occurred. At 2 and 5 h post-alcohol binge, an anti-inflammatory state was shown with reduced numbers of circulating monocytes and natural killer cells, attenuated LPS-induced interleukin (IL)-1β levels, and a trend toward increased interleukin (IL)-10 levels.

CONCLUSIONS

A single episode of binge alcohol intoxication exerted effects on the immune system that caused an early and transient pro-inflammatory state followed by an anti-inflammatory state.

Acute alcohol intoxication and long-term outcome in patients with traumatic brain injury

The effect of blood alcohol concentration (BAC) on outcome after traumatic brain injury (TBI) is controversial. We sought to assess the independent effect of positive BAC on long-term outcome in patients with TBI treated in the intensive care unit (ICU). We performed a retrospective analysis of 405 patients with TBI, admitted to the ICU of a large urban Level 1 trauma center between January 2009 and December 2012. Outcome was six-month mortality and unfavorable neurological outcome (defined as a Glasgow Outcome Scale score of 1 [death], 2, [vegetative state], or 3 [severe disability]). Patients were categorized by admission BAC into: no BAC (0.0‰; n=99), low BAC (<2.3‰; n=140) and high BAC (≥2.3‰; n=166). Logistic regression analysis, adjusting for baseline risk and severity of illness, was used to assess the independent effect of BAC on outcome (using the no BAC group as the reference). Overall six-month mortality was 25% and unfavorable outcome was 46%. Multivariate analysis showed low BAC to independently reduce risk of six-month mortality compared with no BAC (low BAC adjusted odds ratio [AOR] 0.41, 95% confidence interval [CI] 0.19-0.88, p=0.021) and high BAC (AOR 0.58, 95% CI 0.29-1.15, p=0.120). Furthermore, a trend towards reduced risk of six-month unfavorable neurological outcome for patients with positive BAC, compared to patients with negative BAC, was noted, although this did not reach statistical significance (low BAC AOR 0.65, 95% CI 0.34-1.22, p=0.178, and high BAC AOR 0.59, 95% CI 0.32-1.09, p=0.089). In conclusion, low admission BAC (<2.3‰) was found to independently reduce risk of six-month mortality for patients with TBI, and a trend towards improved long-term neurological outcome was found for BAC-positive patients. The role of alcohol as a neuroprotective agent warrants further studies.

Alcohol's Burden on Immunity Following Burn, Hemorrhagic Shock, or Traumatic Brain Injury

Alcohol consumption contributes to increased incidence and severity of traumatic injury. Compared with patients who do not consume alcohol, alcohol-consuming patients have higher rates of long-term morbidity and mortality during recovery from injury. This can be attributed in part to an impaired immune response in individuals who consume alcohol. Acute and chronic alcohol use can affect both the innate and adaptive immune defense responses within multiple organ systems; the combination of alcohol use and injury results in increased susceptibility to bacterial and viral pathogens. This review examines the major deleterious effects of alcohol on immunity following tissue damage or traumatic injury, with a focus on alcohol's influence on the ability of the immune and major organ systems to fight disease and to repair damaged tissues following injury.

The First Line of Defense: The Effects of Alcohol on Post-Burn Intestinal Barrier, Immune Cells, and Microbiome

Alcohol (ethanol) is one of the most globally abused substances, and is one of the leading causes of premature death in the world. As a result of its complexity and direct contact with ingested alcohol, the intestine represents the primary source from which alcohol-associated pathologies stem. The gut is the largest reservoir of bacteria in the body, and under healthy conditions, it maintains a barrier preventing bacteria from translocating out of the intestinal lumen. The intestinal barrier is compromised following alcohol exposure, which can lead to life-threatening systemic complications including sepsis and multiple organ failure. Furthermore, alcohol is a major confounding factor in pathology associated with trauma. Experimental data from both human and animal studies suggest that alcohol perturbs the intestinal barrier and its function, which is exacerbated by a "second hit" from traumatic injury. This article highlights the role of alcohol-mediated alterations of the intestinal epithelia and its defense against bacteria within the gut, and the impact of alcohol on intestinal immunity, specifically on T cells and neutrophils. Finally, it discusses how the gut microbiome both contributes to and protects the intestines from dysbiosis after alcohol exposure and trauma.

Alcohol-related road traffic injuries in Al-Ain City, United Arab Emirates

OBJECTIVE

We aimed to prospectively study the demography, severity of injury and outcome of alcohol-related road traffic collision (RTC) injuries in the United Arab Emirates.

METHODS

Data of RTC Registry of Al-Ain City were prospectively collected from Al-Ain and Tawam hospitals during the period of April 2006 to October 2007. It included all RTC trauma patients who were admitted or those who died after arrival to these hospitals. Car occupants with complete data on alcohol use were included in the study. Patients were divided into two groups, those who reported using alcohol and those who did not.

RESULTS

Out of the 771 car occupants, sixteen (16) used alcohol (2.1%), 15 (94%) of them were males. The median (range) age of the alcohol group was significantly higher than those without alcohol (35 (15-53) years compared with 26 (1-78) years, p = 0.02). The UAE nationals were significantly more (P = 0.01) and the revised trauma score was significantly less in the alcohol group (P = 0.03). Head/face was the most commonly injured region in the alcohol group (94%).

CONCLUSION

Self reported alcohol-related car collisions in Al-Ain City had a low incidence. It affected older Emirati male nationals and was associated with lower revised trauma score, mainly due to head injury. There is a need for a national registry with data on alcohol abuse so as to assess its effects and strategies for its prevention.

Risk score to predict hospital-acquired pneumonia after spontaneous intracerebral hemorrhage

BACKGROUND AND PURPOSE

We aimed to develop a risk score (intracerebral hemorrhage-associated pneumonia score, ICH-APS) for predicting hospital-acquired stroke-associated pneumonia (SAP) after ICH.

METHODS

The ICH-APS was developed based on the China National Stroke Registry (CNSR), in which eligible patients were randomly divided into derivation (60%) and validation (40%) cohorts. Variables routinely collected at presentation were used for predicting SAP after ICH. For testing the added value of hematoma volume measure, we separately developed 2 models with (ICH-APS-B) and without (ICH-APS-A) hematoma volume included. Multivariable logistic regression was performed to identify independent predictors. The area under the receiver operating characteristic curve (AUROC), Hosmer-Lemeshow goodness-of-fit test, and integrated discrimination index were used to assess model discrimination, calibration, and reclassification, respectively.

RESULTS

The SAP was 16.4% and 17.7% in the overall derivation (n=2998) and validation (n=2000) cohorts, respectively. A 23-point ICH-APS-A was developed based on a set of predictors and showed good discrimination in the overall derivation (AUROC, 0.75; 95% confidence interval, 0.72-0.77) and validation (AUROC, 0.76; 95% confidence interval, 0.71-0.79) cohorts. The ICH-APS-A was more sensitive for patients with length of stay >48 hours (AUROC, 0.78; 95% confidence interval, 0.75-0.81) than those with length of stay <48 hours (AUROC, 0.64; 95% confidence interval, 0.55-0.73). The ICH-APS-A was well calibrated (Hosmer-Lemeshow test) in the derivation (P=0.20) and validation (P=0.66) cohorts. Similarly, a 26-point ICH-APS-B was established. The ICH-APS-A and ICH-APS-B were not significantly different in discrimination and reclassification for SAP after ICH.

CONCLUSION

The ICH-APSs are valid risk scores for predicting SAP after ICH, especially for patients with length of stay >48 hours.

Acute alcohol intoxication prolongs neuroinflammation without exacerbating neurobehavioral dysfunction following mild traumatic brain injury

Traumatic brain injury (TBI) represents a leading cause of death and disability among young persons with ∼1.7 million reported cases in the United States annually. Although acute alcohol intoxication (AAI) is frequently present at the time of TBI, conflicting animal and clinical reports have failed to establish whether AAI significantly impacts short-term outcomes after TBI. The objective of this study was to determine whether AAI at the time of TBI aggravates neurobehavioral outcomes and neuroinflammatory sequelae post-TBI. Adult male Sprague-Dawley rats were surgically instrumented with gastric and vascular catheters before a left lateral craniotomy. After recovery, rats received either a primed constant intragastric alcohol infusion (2.5 g/kg+0.3 g/kg/h for 15 h) or isocaloric/isovolumic dextrose infusion followed by a lateral fluid percussion TBI (∼1.4 J, ∼30 ms). TBI induced apnea and a delay in righting reflex. AAI at the time of injury increased the TBI induced delay in righting reflex without altering apnea duration. Neurological and behavioral dysfunction was observed at 6 h and 24 h post-TBI, and this was not exacerbated by AAI. TBI induced a transient upregulation of cortical interleukin (IL)-6 and monocyte chemotactic protein (MCP)-1 mRNA expression at 6 h, which was resolved at 24 h. AAI did not modulate the inflammatory response at 6 h but prevented resolution of inflammation (IL-1, IL-6, tumor necrosis factor-α, and MCP-1 expression) at 24 h post-TBI. AAI at the time of TBI did not delay the recovery of neurological and neurobehavioral function but prevented the resolution of neuroinflammation post-TBI.

Heavy ethanol intoxication increases proinflammatory cytokines and aggravates hemorrhagic shock-induced organ damage in rats

Hemorrhagic shock (HS) following acute alcohol intoxication can increase proinflammatory cytokine production and induce marked immunosuppression. We investigated the effects of ethanol on physiopathology and cytokine levels following HS in acutely alcohol-intoxicated rats. Rats received an intravenous injection of 5 g/kg ethanol over 3 h followed by HS induced by withdrawal of 40% of total blood volume from a femoral arterial catheter over 30 min. Mean arterial pressure (MAP) and heart rate (HR) were monitored continuously for 48 h after the start of blood withdrawal. Biochemical parameters, including hemoglobin, ethanol, glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), blood urea nitrogen (BUN), creatinine (Cre), lactic dehydrogenase (LDH), and creatine phosphokinase (CPK), were measured at 30 min before induction of HS and 0, 1, 3, 6, 9, 12, 18, 24, and 48 h after HS. Serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were measured at 1 and 12 h after HS. The liver, kidneys, and lungs were removed for pathology at 48 h later. HS significantly increased HR, blood GOT, GPT, BUN, Cre, LDH, CPK, TNF-α, and IL-6 levels and decreased hemoglobin and MAP in rats. Acute ethanol intoxication further increased serum levels of GOT, GPT, BUN, Cre, LDH, CPK, TNF-α and IL-6 elevation following HS. Acutely intoxicated rats exacerbated the histopathologic changes in the liver, kidneys, and lungs following HS.