Alcohol Modulation of the Postburn Hepatic Response

Acute ethanol exposure stimulates microvesicle particle generation in keratinocytes

Ethanol has been demonstrated to exert profound effects upon cells and tissues via multiple mechanisms. One recently appreciated means by which cells can communicate with other cells is via the production and release of extracellular vesicles. Though smaller exosomes have been demonstrated to be released in response to ethanol exposure, the ability of ethanol to modulate the generation and release of larger microvesicle particles (MVP) is lesser studied. The present studies examined the ability of exogenous ethanol to generate MVP with a focus on skin cells. Acute ethanol exposure resulted in augmented MVP release in keratinocytes and in the skin and blood of mice. Unlike other stimuli such as ultraviolet B radiation or thermal burn injury, ethanol-mediated MVP release was independent of the Platelet-activating Factor receptor (PAFR). However, ethanol pretreatment was found to augment thermal burn injury-induced MVP in a PAFR-dependent manner. These studies provide a novel mechanism for ethanol-mediated effects, that could be relevant in the significant toxicity associated with thermal burn injury in the setting of alcohol intoxication.

Association Between Alcohol, Substance Use, and Inpatient Burn Outcomes

The use of alcohol and illicit substances has been associated with impaired judgment and health, but the effect on inpatient outcomes after burn injury remains unsettled. Our objective was to evaluate the effect of alcohol and illicit substance use on our inpatient burn outcomes. Adult patients admitted with burn injury-including inhalation injury only-between January 1, 2014 and June 30, 2019 were eligible for inclusion. Alcohol use and illicit drug use were identified on admission. Outcomes of interest included requiring mechanical ventilation, admission to the intensive care unit, length of stay, and inpatient mortality. Multivariable linear and logistic regression models were used to estimate the effects of use on inpatient outcomes. A total of 3476 patients were included in our analyses; 8% (n = 284) tested positive for alcohol, 10% (n = 364) tested positive for cocaine, and 27% (n = 930) tested positive for marijuana and at admission. Two hundred and eighty adults (18% of all positive patients) tested positive for at least two substances. Patients who tested positive for alcohol had longer lengths of stay and were more likely to be admitted to the intensive care unit. Patients who tested positive for cocaine had longer overall and intensive care unit lengths of stay. No differences in inpatient outcomes were seen among patients who tested positive for marijuana. Neither alcohol nor illicit substance use appears to affect inpatient mortality after burns. Alcohol and cocaine use significantly increased overall length of stay. Marijuana use had no impact on inpatient outcomes.

Multiorgan Metabolomics and Lipidomics Provide New Insights Into Fat Infiltration in the Liver, Muscle Wasting, and Liver-Muscle Crosstalk Following Burn Injury

Burn injury mediated hypermetabolic syndrome leads to increased mortality among severe burn victims, due to liver failure and muscle wasting. Metabolic changes may persist up to 2 years following the injury. Thus, understanding the underlying mechanisms of the pathology is crucially important to develop appropriate therapeutic approaches. We present detailed metabolomic and lipidomic analyses of the liver and muscle tissues in a rat model with a 30% body surface area burn injury located at the dorsal skin. Three hundred and thirty-eight of 1587 detected metabolites and lipids in the liver and 119 of 1504 in the muscle tissue exhibited statistically significant alterations. We observed excessive accumulation of triacylglycerols, decreased levels of S-adenosylmethionine, increased levels of glutamine and xenobiotics in the liver tissue. Additionally, the levels of gluconeogenesis, glycolysis, and tricarboxylic acid cycle metabolites are generally decreased in the liver. On the other hand, burn injury muscle tissue exhibits increased levels of acyl-carnitines, alpha-hydroxyisovalerate, ophthalmate, alpha-hydroxybutyrate, and decreased levels of reduced glutathione. The results of this preliminary study provide compelling observations that liver and muscle tissues undergo distinctly different changes during hypermetabolism, possibly reflecting liver-muscle crosstalk. The liver and muscle tissues might be exacerbating each other's metabolic pathologies, via excessive utilization of certain metabolites produced by each other.

Bias in alcohol and drug screening in adult burn patients

Alcohol and illicit drug use are common among burn-injured patients. Urine toxicology and alcohol screens are a part of our admission order sets and automatically ordered for all adult patients. Our objective was to determine the impact of bias in screening compliance and compare those results to patients who test positive. All adult patients admitted between January 1^st, 2014 and December 31^st, 2018 were eligible for inclusion. Multivariable logistic regression was used to identify potential predictors for compliance in obtaining samples for screens, and patient characteristics associated with testing positive. Four thousand nine hundred ninety-eight patients were included in the study. The biggest predictors for compliance in obtaining samples for screens were inhalation injury, intensive care unit stay, length of stay, burn size, and current smoking status. No differences in compliance with screens were seen across age, race, or ethnicity. Current smokers and patients with a history of major psychiatric illness were more likely to test positive for alcohol and illicit drugs. Non-Hispanic Black patients were more likely to test positive for illicit drugs. Male sex and pre-existing psychiatric conditions were significant predictors for compliance for alcohol screens, and, positive tests. Implicit bias based on age, race, or ethnicity played no predictive role in compliance for either screen, however, non-Hispanic Blacks were more likely to test positive for illicit drugs. More studies are needed to understand the effect of selection bias related to sample collection, and the significance of positive test results.

The role of concomitant alcohol and drug use in increased risk for burn mortality outcomes

BACKGROUND

Burn injuries are a major cause of mortality and morbidity in low- and middle-income countries, with high rates in Sub-Saharan Africa. The risks may be heightened for persons who present with concomitant use of alcohol and illicit substances, which increase the risk for injury and severely compromise prognosis following injury.

METHODS

This study utilised a national dataset on hospitalised burns in South Africa to explore the risk for mortality relative to morbidity. To assess the influence of alcohol and drugs in mortality outcomes, the analysis was restricted to adult cases, 18 years and older (N = 918). The primary statistical procedures used in the analysis were logistic regression models.

FINDINGS

The results indicate that burn victims with full thickness and partial thickness burn degree and more than 30% TBSA had a significantly increased risk of mortality. In addition, the risk for mortality was increased ten times when concomitant alcohol and drugs were indicated compared to cases where these were absent. The length of stay in hospital diminished the risk for mortality by about 10%.

INTERPRETATION

The findings may be explained by the role of skin as the main barrier against infections and the concurrent increase in risk of infection based on the degree and extent of any damage. The combined presence of both alcohol and drugs may predispose towards more severe burns and greatly compromise liver function with heightened risk for sepsis and death.